the clean two-stroke thread [Archive]

Haufen

13th July 2020, 08:34

As our beloved two-strokes are likely to disappear in the not so distant future, this thread shall serve as pool a for anything clean two-stroke related.

The goal of this thread is to provide information, share the latest news and publications on two-stroke technology and discuss possible ways and technologies which would make for a clean yet still rather simple engine, especially:

- found an interesting link or engine or new tech on a two-stroke? Post it here.

- basics: why are two-strokes 'dirty' in comparison to four strokes (no, it's not the oil burning)

- brainstorming: what would a clean two-stroke ideally look like? Which technology / features would it use?

- bonus: if we find our brainstorming to be successful and maybe worth looking at more indepth, we might as well forward and / or publish our ideas or just build something by ourselves.

-----------------

Basics:
why two-strokes are 'dirty' and most four strokes are not that clean either. An excursion into emissions and legislation.

This is a work in progress, I will fill in further bits soon and try to keep it as compact as possible.

1) there are different kinds of emissions
NOx, CO2, HC, PPM etc. --> what is it, where does it come from and do we really need to know all of this?

2) main reason why two-strokes are referred to as 'dirty' (still not the oil burning)

3) legislation --> how clean do you need to be?

4) let me know if there is a special topic of interest you would like me to focus on, also. I have accompanied the development of a clean two-stroke engine in the past where I was responsible for performance and emissions. Due to an NDA I can not get too specific on that particular engine, but there are many general aspects which can be focused on.

---------------

I am looking forward to many interesting discussions!

ceci

13th July 2020, 10:55

I do not know if it is a mistake of mine or the less gray smoke I see coming out the more flame comes out when the lighter close

https://www.facebook.com/calaganne.dx/videos/288873407815868/

Flettner

13th July 2020, 17:34

Uniflow block, opposed piston, 640cc. Differential piston sizing, larger transfer piston, smaller exhaust piston. Utilizes squish as a cosiquence of these differnt piston diameters. Two plugs per cylinder. I might have gone a bit too extreme on this one I think.

Flettner

13th July 2020, 19:00

I guess Im allowed to insert this image?

WilDun

13th July 2020, 20:12

Good to see you have this thread under way and I hope it brings a lot of ideas online! - I won't launch into any big discussions (just yet).:laugh:

As you no doubt know, I believe the "visible" pollution ('smoke') as seen by the general public (consumers) has a huge impact on sales these days - I acknowledge they are only seeing the tip of the iceberg of course, but that alone will contribute to a change in course, (ie using four strokes instead) to keep consumers happy! - the smoke alone is a bad look today and (rightly or wrongly) it is seen as the culprit and puts people off two strokes!

Good luck and thanks for starting the thread Haufen. :niceone:

ceci

13th July 2020, 20:28

Good to see you have this thread under way and I hope it brings a lot of ideas online! - I won't launch into any big discussions (just yet).:laugh:

As you no doubt know, I believe the "visible" pollution, seen as 'smoke' by the general public (consumers) has a huge impact on sales these days - I acknowledge they are only seeing the tip of the iceberg of course, but that alone is/has contributed to a change of course, to keep the consumers happy!.

Good luck and thanks for starting the thread.

The double rule of the game allows these types of solutions, which are only commercial solutions.
With them the Euro4 homologation standards are met and the majority of the population that demands that they are met is satisfied.
And the owner is allowed, if he wishes, to manipulate the system according to his own criteria.

BMWST?

13th July 2020, 20:36

Pursang

14th July 2020, 00:40

a good portion of the new intake charge is lost out the ehaust port.One of the most promising ideas in my mind would be a fuel injected two stroke where the fuel is injected AFTER the exhaust port is closed

Sounds Simple doesn't it? :yes:

Issues include the need for a fully vaporized fuel air mixture, before ignition.
One of the advantages of crankcase induction is that the mixture enters at say 20C. then thrashes around in there for around 15 cycles, absorbing heat from the crank & rod & bearings & Piston & cylinder wall, to finally be transferred to the cylinder at up to 100C. Hopefully thoroughly mixed and no longer Wet and hard to completely burn. (Not guaranteed, in my experience).

Some of the Direct Injection techniques include Very High pressure, to maximise atomisation, or injecting fuel pre-mixed with air.
Mahle's "new" process with pre-combustion in a pre-injection chamber will need to prove to be commercially successful in Automobiles (again) before it ever gets applied to 2 Strokes.

Flettners TPI uses injection against the transfer air flow to good effect, but afaik, this is not timed to EPC.

Another technical/mechanical problem is the very short time period available between EPC & ignition as rpm increases.

Cheers, Daryl

Niels Abildgaard

14th July 2020, 02:01

Make a side-exhaust valve and inject fuel directly on valve

https://i.imgur.com/Iz3tD97.jpg

WilDun

14th July 2020, 12:20

As our beloved two-strokes are likely to disappear in the not so distant future, this thread shall serve as pool a for anything clean two-stroke related.................
- bonus: if we find our brainstorming to be successful and maybe worth looking at more indepth, we might as well forward and / or publish our ideas or just build something by ourselves.

-----------------

Basics:
why two-strokes are 'dirty' and most four strokes are not that clean either. An excursion into emissions and legislation .......

1) there are different kinds of emissions
NOx, CO2, HC, PPM etc. --> what is it, where does it come from and do we really need to know all of this?

2) main reason why two-strokes are referred to as 'dirty' (still not the oil burning)

3) legislation --> how clean do you need to be?

4) let me know if there is a special topic of interest you would like me to focus on, .......

---------------

I am looking forward to many interesting discussions!

We understand that you will be a little restricted and not be able to disclose specific things - but hopefully you will still be able to provide some interesting stuff here (otherwise you wouldn't have started the thread) - patents are a totally separate subject and tend to take away a lot of pleasure from those people who just like to invent things, but unfortunately they are reality!

A slightly modified excerpt from a post I made on "Oddball" thread ;-
In a road going machine it has to cope with constantly being used throughout the rev range from idle to full revs ( it is not good at doing that!) - it prefers to be efficient at a certain part of the rev range! I'm not a fan of chambers as some of you might know, but ironical as it might be, expansion chambers could possibly be excellent in that rev band!! - however I still see the mixing of incoming and outgoing gases as a problem and this will cancel out its usefulness - that, along with both the Schneurle transfer system and squish combustion chambers!

Burning oil emissions, although apparently not the real culprit, still needs to be addressed though, it is highly visible and it matters to the general public who, no matter what, will still percieve it as being bad and go for a four stroke instead - and they are the potential customers who can keep it all going!

O.P. engines using HCCI style combustion and the use of hybrid type transmission (without huge battery packs) could help to cure many of the above problems .....but of course, they do have their drawbacks as well! - All this may be only my theory, but I believe in it, and will do till someone proves me wrong!

Norman

15th July 2020, 08:32

I guess Im allowed to insert this image?

Flettner, do you have an idea how good the TPI system is to avoid fuel short cutting out the exhaust? That is to lower emissions. Is there a need for a Direct Injector in addition to the TPI to optimize for emissions you think?

Flettner

15th July 2020, 10:32

Flettner, do you have an idea how good the TPI system is to avoid fuel short cutting out the exhaust? That is to lower emissions. Is there a need for a Direct Injector in addition to the TPI to optimize for emissions you think?

Well, this TPI bike delivered 14 / 21 % fuel savings over my carburetor YZ, depending on how much 'on pipe' work. Same day, same track, alternating riders. Over many events. Dyno test showed similar top end power between the two bikes.
DI is a sledge hammer to crack a nut, expensive and complicated.
All this just because the exhaust port is too close to the transfers. Thats why my new engine devlopment has gone back to opposed piston. I believe I could get similar or better emmissions using a carburetor (with uniflow) as a DI engine. In saying that I will be using a form of TPI on my new Uniflow.

Murray

15th July 2020, 18:40

The big come back

https://www.stuff.co.nz/motoring/122124935/twostroke-motorcycles-might-be-coming-back

TZ350

15th July 2020, 19:02

Flettners TPI uses injection against the transfer air flow to good effect, but afaik, this is not timed to EPC

346443

A lot of the air that short circuits out a two strokes exhaust port comes from the A transfer ports.

With the injectors in the B ports you lose mostly clean air through short circuiting. The injectors should be timed to finish somewhere between BDC and TPC where the pipe should be sucking its hardest.

Not all the air transferred gets fuel injected into it. Some is lost to the exhaust system. Hopefully mostly clean air from the A ports. It is the last bit of air drawn into the cylinder around BDC and before TPC is what we hope to keep trapped in the cylinder. Hopefully most of the air from the B ports with the fuel in it.

This end point timing can also minimize the amount of fuel expelled back out through the carburetor. Proper timing of the injection end point can noticeably help with fuel efficiency and exhaust cleanliness.

Well, this TPI bike delivered 14 / 21 % fuel savings over my carburetor YZ, depending on how much 'on pipe' work. Same day, same track, alternating riders. Over many events. Dyno test showed similar top end power between the two bikes.

ken seeber

15th July 2020, 23:26

Firstly, good on you Haufen for creating this page.

Ceci, that’s beautiful. At Orbital we used FID (flame ionization detection) instruments (Beckman and Horiba) for HC detection. Lots of explanations of these, here’s just one: https://www.youtube.com/watch?v=BJzqdzLY2KU The one in the vid is a superb example of the issue, unburnt HC’s aplenty.

This confirms the main issue with 2 strokes: unburnt HCs.

NOx levels are inherently low. These are created by high pressures and temperatures. A 4 stroke only fires every second rev, so, power for power, its pressures and temps are higher. A win for 2 strokes.

Norman suggested fuel injection after EPC. Getting the fuel into the cylinder before EPC and therefore mechanically prevent fuel loss out the exhaust was exactly what Orbital and ETEC were doing. Mind you, certainly the Orbital system injected well before EPC at high speeds and loads, but this took into account the transportation time of the fuel charge.

Neil’s pursuance of the OP principle is sound, essentially putting the fuel charge into the working chamber some distance away from the exhaust port(s).

The goal of getting 2 strokes to be clean is to complete the combustion process within the engine, not in the exhaust or never.….

ceci

16th July 2020, 04:23

This forum brings together the two best systems used to inject into the commercial 2S (DiTech & TPI).
The solution may be found in a fusion of both?

Niels Abildgaard

16th July 2020, 05:54

A imoral combination of fuel injektor and exhaust valve
346464

WilDun

16th July 2020, 11:53

All very good ideas of course and most are actual reality through 'in field' experimentation - all good so far.

Just a couple of questions from an armchair (wannabe) engineer, - Is it true that NOx is formed in the squish clearance gap between the head and piston of current two strokes??

When we say that the transfer charge going into the exhaust from the 'A' ports is pure, what about the oil in that air? - I'm always rabbiting on about it I know - but after all, this is the cause of two stroke smoke (which no one seems to think is important) and some point out that you don't see it when going at speed.

Racing isn't the problem, it's puttering around the streets and taking off from an idle where the problem lies! so I believe it is very important - that's mainly why the two stroke has become the enemy.
Just about everything it puts out will be opposed by the "Greenies" and the general public (whose opinion is very important in all this) will see smoke as being obnoxious and will back them up! - smoke from the exhaust is often perceived by some to be 'smelly', but (significally) it is highly visible and not a good look these days!

Vannik

16th July 2020, 18:27

ceci

16th July 2020, 19:41

A lot of the air that short circuits out a two strokes exhaust port comes from the A transfer ports.

With the injectors in the B ports you lose mostly clean air through short circuiting. The injectors should be timed to finish somewhere between BDC and TPC where the pipe should be sucking its hardest.

Not all the air transferred gets fuel injected into it. Some is lost to the exhaust system. Hopefully mostly clean air from the A ports. It is the last bit of air drawn into the cylinder around BDC and before TPC is what we hope to keep trapped in the cylinder. Hopefully most of the air from the B ports with the fuel in it.

.
The TPI to be effective there has to be a strong countercurrent that vaporizes the spray (otherwise it only deposits in the crankcase) and this only occurs in the mid-high RPM zone.
The transfer & admission at low RPM is only a smooth movement of gaseous masses with few inertias.

I
A standard Ditech runs up to about 8,000 rpm and surprisingly, un restricted to about 10,000 which is good but I think about their limit. A single injector also limits things to 10,000 RPM or less. Simply because an injector small enough to allow good low speed tuning becomes to small to get things done in the limited "Time" available at higher RPM. .

This is an attempt to fix that problem you describe

https://dirtbiketest.com/wp-content/uploads/2017/05/early-Direct-Injection.jpg

What is suggested is to use the DiTech as a main jet and the TPI as a power jet

TZ350

16th July 2020, 20:41

What is suggested is to use the DiTech as a main jet and the TPI as a power jet

Yes, I like that idea.

WilDun

17th July 2020, 00:25

NOxes are formed above a certain temperature which is what the squish is trying to avoid, to prevent detonation. This does lead to unburnt hydrocarbons.

With a modern controlled oiling system the low speed smoke can be almost eliminated by supplying the oil required by the load and not just a function of rpm.

Thanks Vannik,
I lived and rode bikes from the early sixties and started using this wonderful new "ashless" two stroke oil - all designed in the interest of reducing smoke and pollution!
A little later (late sixties) I had a 250cc Suzuki twin - it had a pump oiling system with the oil guided into main and big end bearings (hailed as a breakthrough then), then it disappeared and only now (50 something years later) I have seen it being hailed as a breakthrough - in these pages!
The pump could be adjusted and was controlled from the throttle position - it still smoked like hell, no matter how you set it! and after moving away from bikes for around 40 years, I have come back to study them again and have found that not a helluva lot has changed except 'band aid' additions to prop up its failings! - any real improvement was biased toward improving the horsepower and levelling the torque curve! - this was all happening when the 2 stroke was disappearing fast from our roads! - so that is why I am very sceptical (yes that's how we spell it here :yes: ) about all the "new innovations"!

Perhaps I'm wrong, but I'm just not seeing any real moves toward a clean machine - I do hope there are some convincing attempts in the pipeline!
:scooter:

Norman

17th July 2020, 09:33

Well, this TPI bike delivered 14 / 21 % fuel savings over my carburetor YZ, depending on how much 'on pipe' work. Same day, same track, alternating riders. Over many events. Dyno test showed similar top end power between the two bikes.
DI is a sledge hammer to crack a nut, expensive and complicated.
All this just because the exhaust port is too close to the transfers. Thats why my new engine devlopment has gone back to opposed piston. I believe I could get similar or better emmissions using a carburetor (with uniflow) as a DI engine. In saying that I will be using a form of TPI on my new Uniflow.

That is quite an improvement! Up to 21%..same power. Much less fuel escapes out the exhaust.

BRP has a solution on their 850 ETEC machines with an extra "boost" injector at the inlet. I was thinking with two TPI injectors the DI injector could be made with smaller finer spray for low load up to "medium" rpm. And as mentioned above use the TPI as "power jet".

Pursang

17th July 2020, 10:50

Firstly, good on you Haufen for creating this page.......

........Neil’s pursuance of the OP principle is sound, essentially putting the fuel charge into the working chamber some distance away from the exhaust port(s).

The goal of getting 2 strokes to be clean is to complete the combustion process within the engine, not in the exhaust or never.….

Ken, your pursuit of Squishband Reed transfer is sound too, for the same reason. This is the ideal place for an update...Please!

Cheers, Daryl.

Flettner

17th July 2020, 12:35

That is quite an improvement! Up to 21%..same power. Much less fuel escapes out the exhaust.
".

The 21% was achieved on a very tight slow trail ride track with bugger all on pipe work. That appears to be where the worst area is for a carburetor bike. Even though the transfer steams aren't high inertia, the B port injector placement and timing have a big part to play in TPI efficiency.

husaberg

17th July 2020, 18:35

it may have been discussed but why not let time and overlap be your friend rather than enemy
why do we need a bike that revs to 14000 RPM?
We are not talking competition here where a engine of 125cc or whatever is ran to the extreme.

What about an extreme long stroke engine.
say 65mm bore and 105mm strioke
For no better reason than this gives 350cc and arround about 25ms at a max of 7000rpm

a 4T dirt bike of around that size would be 30-35 HP at the wheel.
As a KTM300 is more than fast enough for a non expert they make about 50HP
40 is likely what a CR500 made.

So somewhere in between maybe 40HP
if someone plugs in these bore and stroke into the Sim
with 180 duration a very mild pipe 30mm carb and a RGV250 reed valve
What does it look like?
With a long stroke and little little overlap i am picking it would be pretty clean.
Also with a low rev ceiling it would have the time to run DI.

Neils Sleeve i wager could be very clean if it was tuned for it

Pursang

18th July 2020, 10:37

it may have been discussed but why not let time and overlap be your friend rather than enemy.......

.......if someone plugs in these bore and stroke into the Sim
with 180 duration a very mild pipe 30mm carb and a RGV250 reed valve
What does it look like?
With a long stroke and little little overlap i am picking it would be pretty clean.
Also with a low rev ceiling it would have the time to run DI.

Ah Ha!, the KISS approach:p......maybe add in a big 'step' at the exhaust port and work on the A transfers for shortcut proofing rather than Max HP.

Cheers, Daryl.

husaberg

18th July 2020, 10:50

Ah Ha!, the KISS approach:p......maybe add in a big 'step' at the exhaust port and work on the A transfers for shortcut proofing rather than Max HP.

Cheers, Daryl.

A ex dam yes
a Deflector piston well i would not rule that out either ;)
But yes.

The long stroke does give some obvious advantages if not chasing the nth degree of performance.

If i was being serious the CRM250 would be the starting point i guess.
Anyone ever rode or seen one.
I have posted the trapping valve before which was something Lotus were believe working on maybe for GM

WilDun

18th July 2020, 13:00

Husa, you are seeing things from the right perspective rather than from a competition/racing perspective only and that's refreshing!
I also do think we should rewind a little!

Toyota (and maybe others) did that - ie they made their bore/stroke 'under square' way back in the late eighties - they were four strokes of course but reaped great benefits with torque - they were good or better in that department than engines with fancy VVT etc and perfectly good for the average guy on the roads!

I feel that with the old 'split single' two strokes (championed by Puch) there was a great opportunity to keep the charges separate, but I felt that 'squish' and it's problems might be an obstacle there
However, Haufen indicated that it is probably not the problem I believed it might be - so I'll listen to him and consider the split single.

Pursang

19th July 2020, 11:37

a Deflector piston well i would not rule that out either ;)

I'm impressed by Mr Scott's solution to creating efficient, compact combustion chamber(s), with squish, while using a deflector piston.:clap:

He did this over 100 years ago! A modern update of this configuration would not be difficult!

Maybe 3 or 4 chambers with 10mm plugs instead of the 19's or 22's that Scotty used. But, he could change the compression ratio by changing the plug reach!::msn-wink:

Note the decompressor valve 1/2 way up the cylinder wall (above Ex port). Similar one in the 490 Maico I'm working on (but in the back wall).
Kick starting with it engaged is like kicking over a 175! Thank Goodness!

Fact: Scott patented the Kickstarter (as we know it) in 1908

Cheers, Daryl

190mech

19th July 2020, 12:00

Husa's long stroke idea interested me,as I have no fancy calculator gizmo stuff,decided to do it by hand/mind..Tried to find the longest stroke 2stroke motorcycle engine,found the KX500(86x86),has a 145mm rod,scaled that up for a 105 stroke =177mm,went to torqsoft and plugged in 180 and 120 degree for a 105 stroke/177 rod motor,got the numbers and made a full scale drawing,looks quite strange compared to the normal race stuff we see..346490

Perhaps this is all wrong,but it is interesting to see how bore to stroke ratio alters port dimensions for a set degree angle..

WilDun

20th July 2020, 10:37

Husa's long stroke idea interested me,as I have no fancy calculator gizmo stuff,.........................
Perhaps this is all wrong,but it is interesting to see how bore to stroke ratio alters port dimensions for a set degree angle..

Sometimes the "suck it and see/trial and error" approach is the best way to go! - guess it depends on what the goal for the machine is! - This thread is not only for high performance machinery, but for finding out how we can save the two stroke before it disappears completely!

I believe that it would take a massive shift from the norm to get the two stroke back to where it should be! (maybe not impossible), but it's future is really controlled by ignorant people in high places and their "greenie" supporters, so first off we need to look for something to change their minds! (like NO visible smoke), -
It probably isn't the main problem, but how it is "seen to be" by a lot of people, does matter and will also affect its chances of survival,
(whether we like it or not!).

ceci

21st July 2020, 21:49

The success of the TPI as an anti-pollution system establishes the future of the 2S within the semi-direct fuel injection system.
And how can TPI be improved? My opinion is that it must be transformed to meet the requirements described in the first photo, lower price and weight (framed), and only then can it reach the continents (framed) in the second photo.
What transformation ?:
fewer components is less weight and less price.
How can that be done ?:
changing the way it is controlled (setting aside the electronics)
changing the way fuel is pumped (no energy consumption to perform it)
changing the way of injecting (with exclusive injectors)

Flettner

22nd July 2020, 14:44

No real interest in opposed piston uniflow?

ken seeber

22nd July 2020, 15:51

Ceci, on Page 1 of this thread you posted a pic of a Derbi that clearly has a catalyst. I looked up Derbi and, yes, it is real and it meets Euro4 and it looks to have a carb. One would think that TPI plus the cat would be pretty good.
Can't deny the incremental cost of incorporating TPI though.

Niels Abildgaard

22nd July 2020, 16:54

No real interest in opposed piston uniflow?

Interest yes,but not enough to invest.
We are dreaming one or two cylindered engines and when synchronized by gears we get noise and trouble in great amounts.
Having piston controlled exhaust is reason for demise of normal small two strokes.Having one piston doing nothing else is not improving chances much.
Many many years ago I wrote that the Junkers problem was best solved by using power symetrical from the two cranks be it either driving two propellers or generators.
I closed my eyes to the fact that this does not solve the piston rings over exhaust ports problem.
The two AC generator scheme worked first try but do not solve the ring problem

https://web.archive.org/web/20080501215400/http://www.iet.aau.dk/sec2/junkers.htm

ken seeber

22nd July 2020, 17:25

Flettner

22nd July 2020, 17:33

Interest yes,but not enough to invest.
We are dreaming one or two cylinderebd engines and when synchronized by gears we get noise and trouble in great amounts.
Having piston controlled exhaust is reason for demise of normal small two strokes.Having one piston doing nothing else is not improving chances much.
Many many years ago I wrote that the Junkers problem was best solved by using power symetrical from the two cranks be it either driving two propellers or generators.
I closed my eyes to the fact that this does not solve the piston rings over exhaust ports problem.
The two AC generator scheme worked first try but do not solve the ring problem

https://web.archive.org/web/20080501215400/http://www.iet.aau.dk/sec2/junkers.htm

This one seems to go alright, Neils. It did a lot of work in this boat, until the boat hull owner wanted it back. Still got the engine tucked under my bench.
https://youtu.be/uiXsPkP9jvw

husaberg

22nd July 2020, 17:40

Niels,

"I closed my eyes to the fact that this does not solve the piston rings over exhaust ports problem.
The two AC generator scheme worked first try but do not solve the ring problem"

What specifically do you mean by the ring problem.

i assumed he meant the oil needing to lubricate it and getting passed into the combustion chamber.

Husa's long stroke idea interested me,as I have no fancy calculator gizmo stuff,decided to do it by hand/mind..Tried to find the longest stroke 2stroke motorcycle engine,found the KX500(86x86),has a 145mm rod,scaled that up for a 105 stroke =177mm,went to torqsoft and plugged in 180 and 120 degree for a 105 stroke/177 rod motor,got the numbers and made a full scale drawing,looks quite strange compared to the normal race stuff we see..346490

Perhaps this is all wrong,but it is interesting to see how bore to stroke ratio alters port dimensions for a set degree angle..

The idea with the super long stroke is we dont need to rev it to the moon for non GP
and the port area will be made up with height rather than width and overlap %?
less rev less need for overlap anyway. Smaller bore less squish width less so less emissions
smaller bore tighter and smaller combustion chamber
The Conrod length on MX bike especially big bore ones were in my opinion dictated not by engine performance, but ability to fit into the same or similar chassis as a 125 and 250
The rod ratio should be at least 2x stroke min
but we can play with this and the pin offset esp with very long strokes.
IN HINDSIGHT MAYBE 180 DEGREES IS TO MUCH EX DURATION

On your picture i think the lower part of the EX port needs to be blocked off about 10mm from the bottom
346515346490
Some of the Trails bikes had either direct or throttle body injection
I will dig up some EXP stuff
but basically it was a trapping valve that allowed it to autoignite when it would be 4 stroking.
although the racer was originally EFI Honda said it could be run as a carb they designed it to be emissions friendly 400cc but the power of a 650 4t

ken seeber

22nd July 2020, 18:41

At Orbital, we also did 2 versions of an externally scavenged engine: 3 cyl 1.0 litre and 6 cyl 2.0 l. Both were externally scavenged with a blower and both had a pressure fed plain bearing crank and rods; ala 4 stroke wet sump.

Pistons incorporated the same combustion bowl as per the other 2 stroke injected engines that we were working on at the time. The prime reasons for the engines were to demonstrate a reduced cost of mfg and improve the NVH, more specifically the noise (mechanical clatter). The latter was achieved.

The pistons were full skirted with an oil ring at the base of the skirt, this stopped a few mm below the bottom of the exh port.

Obviously there was shitloads of oil on the bores, but this did not cause any perceived smoke issues. I am pretty sure we used 2 stroke oil as this does not have the zinc and phosphorous additives (that are necessary for 4 strokes due to the extreme pressures of the cam lobes), these causing problems with poisoning the catalysts.

Downsides are a heavier piston and more friction.

This pic shows a piston we did for a customer (86 * 86), very similar in style to the ones we used.

346516

Niels Abildgaard

22nd July 2020, 18:51

This one seems to go alright, Neils. It did a lot of work in this boat, until the boat hull owner wanted it back. Still got the engine tucked under my bench.
https://youtu.be/uiXsPkP9jvw

Somewhat noissy.
I have seen a Junkers engine like that in Dessau made by a mr Heintz running HCCI on LPG ( no mean feat )and it made less noise and sired no ofsprings either.

Norman

22nd July 2020, 19:04

Flettner

22nd July 2020, 19:40

Regarding emissions. The following preview of a SAE paper is interesting, the last two pages not in the preview is not necessary to get the picture. Proposals to counteract Particle emission (PM) is not presented in detail (EURO5 demand if using DI but not PI, Flettner-TPI for example).

https://www.sae.org/publications/technical-papers/content/2018-32-0042/preview/

BRP has filed for PCT patent with one solution for rotating exhaust valves. Filed end of 2017. WO2019101981 (A1). To me it looks as if it will be granted at some point.

Flettner, you could maybe consider to apply patent on some of your inventions, I think. You can check, often countries have programs to help inventors to finalize their applications/designs and to get help from for example a Patent Attorney. You are obviously working on solutions that can be used in for example hybrid solutions. Solutions aiming for decreasing pollution and/or having the potential to give job opportunities, in the end, is interesting for the governments.

HaHa, sadly not ours. Talk talk talk but no do, thats New Zealand for you, I have approached two universities now, not interested. The only person I could intetest years ago was John Britten but he wanted OP uniflow to get around the number of cylinders rules for GP racing not emissions.
Patent Attorneys are not efficent, financially, personal experiance.
Who is seriously intetested? There are a lot of talkers.

NZ has now stopped selling E85, I talked to the Green party about what they might do to fix this, they just said we all need to be electric, with seemingly not a thought to where that 'magic' might come from.
Boy do I sound like and angry old man.

I'm in this for the challenge, but I will be keeping my OP developments to myself this time. My problem is I enjoy this kind of work, pitty It doesn't pay.

husaberg

22nd July 2020, 20:09

HaHa, sadly not ours. Talk talk talk but no do, thats New Zealand for you, I have approached two universities now, not interested. The only person I could intetest years ago was John Britten but he wanted OP uniflow to get around the number of cylinders rules for GP racing not emissions.
Patent Attorneys are not efficent, financially, personal experiance.
Who is seriously intetested? There are a lot of talkers.

NZ has now stopped selling E85, I talked to the Green party about what they might do to fix this, they just said we all need to be electric, with seemingly not a thought to where that 'magic' might come from.
Boy do I sound like and angry old man.

I'm in this for the challenge, but I will be keeping my OP developments to myself this time. My problem is I enjoy this kind of work, pitty It doesn't pay.

Hondas original NR had 8 pistons but 4 combustion chambers it was ruled to be legal but Honda didnt want to be accused of cheating so went oval pistons.
You need to get get a Elon musk or Bedos to sponsor you.
The guy that did the Modern scott Silk had non Schnuerle porting
they were deflector and gave good MPG and power.
but were hamstrung with certain Scott designs like the overhung crank.
Something like these would be great light agile and a spondon chassis.
target a R6 performance i guess.
https://www.pressreader.com/australia/old-bike-australasia/20161001/282385513988156

Some pre war Villiers they were 4 transfers and two exhausts with one exhaust over the inlet. 9D.
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i cant find a decent pic but they are described as 4 transfer so i assume its 2 front and 2 rear.

WilDun

22nd July 2020, 22:11

I don't think that a guy with a home workshop ( even coming up with radical and successful stuff would really stand a chance in the patent scene today without a big company (with smart lawyers) backing him and shouldering the costs !

Then there are big and influential people in this world, using politics and financial clout to twist a patent to suit themselves or in some cases just ignoring it altogether!

So yeah, a good idea to carry on as enthusiasts and just keep our little victories to ourselves! - I'm getting to an age now where I can not see any point in guys trying to successfully develop a product, just to have it snatched from under their noses and being unable to do a thing about it!

Life's too short to put yourself through all that stress - I watched a guy from Europe (not too long ago) trying to be big time in the international scene and who more or less went down still kicking and fighting and finally getting nowhere - very very sad to see!) - but still, the sense of achievement you would get from beating the big boys from home must be fantastic!

I will never achieve even that, but I'm just as enthusiastic as I was 54 years ago when I first arrived in NZ - and way before that!!

husaberg

22nd July 2020, 22:36

Pursang

23rd July 2020, 00:43

Norman

23rd July 2020, 04:56

HaHa, sadly not ours. Talk talk talk but no do, thats New Zealand for you, I have approached two universities now, not interested. The only person I could intetest years ago was John Britten but he wanted OP uniflow to get around the number of cylinders rules for GP racing not emissions.
Patent Attorneys are not efficent, financially, personal experiance.
Who is seriously intetested? There are a lot of talkers.

NZ has now stopped selling E85, I talked to the Green party about what they might do to fix this, they just said we all need to be electric, with seemingly not a thought to where that 'magic' might come from.
Boy do I sound like and angry old man.

I'm in this for the challenge, but I will be keeping my OP developments to myself this time. My problem is I enjoy this kind of work, pitty It doesn't pay.

Yes, to take help from Attorney can be painfully expensive for a private person. A lot you can do yourself (with the right Attorney) but It is however shit difficult to write the patent completely on your own. If I had a good Idea, I wish I had a retired Attorney friend or family member.. Then you have the filing cost. But some countries/regions encourage patents. For example Canada seems to try and keep filing costs down to a number of $100. Quite cheap also to get a representative there (must have) to file it for you. Also interesting when EU late 2021, hopefully, get the "EU unity patent" in place. With one application you get a patent automatically granted in about 30 countries. The yearly fees will be "reasonable".

Your work is for sure appreciated by many and it is for sure fascinating!

So they do not sell E85..? As I understand, it is now possible to easier convert CO2 to ethanol (don't ask me the very details), let's see if it soon can be developed into a fully industrial scale.

I believe the combustion engine in different forms is here to stay for a long time yet. Plenty of time for you to come across future new possibilities.

Flettner

23rd July 2020, 08:06

Thankyou, all well considered responses.

Cost of patenting is one thing, defending it is another. Years ago a patent attorney told me I would need at least $100,000 USD to defend a patent on my orginal Uniflow design. I did provisionally patent it but in those days no one was interested in taking up OP uniflow.

My new design is quite different and will work as a single cylinder, old one relied on pairs of cylinders.

Anyway no use even thinking that far ahead yet, lets see how well it works first. If you have been looking at Bucket Foundry you will see I've been having some manufacturing issues. This will be rectified shortly as Im in the process of converting my CO2 wood core boxes to metal dies, shell sand process. This will solve the problem. What did I read recently, Ken, 'success is the ability to move from one failure to the next, without losing enthusiasm'. So jolly true.

WilDun

23rd July 2020, 09:38

So, Lets use the only Power we little guys have and Stick it to the MAN!....:finger:

Public disclosure renders your/any Brilliant Idea no longer 'novel'....:Oops:

A patented invention must be novel. Exposure in a 'public forum' such as this renders it 'common knowledge' :yawn: and no longer eligible for patent.:nono:

So a major European company cannot patent the brilliant idea of someone who develops something special and allows info about it to be published on the other side of the world. :violin:

Nice outline of the process here from PhoenixIP , or they might be very helpful if you Do want to protect your invention:
http://www.phoenixip.com.au/patents/keep-secret-public-disclosure-patent-validity/

Fortunately, we have a worldwide group of clever people, "knowledgeable in the art", to keep a look out for Pricks who think the rules don't apply to them.:2guns:

Cheers, Daryl

Looks like we have to decide whether we are in it for the hobby, or make it a serious business and if we do decide that we're serious about patenting there will be a quantum leap! and very quickly our happy little hobby will become our "back in the happy old days" and our new all consuming hobby will be in defending ourselves, consuming all our time and money and at the same time destroying any inventive ability (through lack of time) in doing so! (example the Wright brothers, and many many others).

Harry Ferguson and Henry Ford were a strange case, they were good mates it would seem till Ford's son took over and then there was turmoil when he took control of Ferguson's patent being used on Ford tractors (it had all started with only a "handshake agreement).

In the end Ferguson (supposedly) won and it continued for a while as the Ford Ferguson, then Ferguson started to produce his "Ferguson" (basically a copy of the Ford tractor but now fitted with the excellent (Standard designed) engine and of course fitted with his hydraulic system. - didn't do a lot of good though - Ferguson, who even though he was a success, eventually took his own life.
So the moral is :- "success" doesn't always guarantee happiness in life!

Generally though, I think that we all believe that a clean two stroke engine could bring happiness!....... Eh! :msn-wink:

Pursang

23rd July 2020, 15:03

Generally though, I think that we all believe that a clean two stroke engine could bring happiness!....... Eh! :msn-wink:

I'm with you Bill!:niceone:

30 years ago I was arrogant enough to think I could improve the world AND be handsomely rewarded for it.:nya:

Now, I'm just happy to be here to witness the efforts and progress of some Very Clever, Capable, people and add my encouragement & 0c worth, when I can!:wavey:

Cheers, Daryl.

ceci

23rd July 2020, 21:29

Sorry again for casting another video in Spanish.
This video is only 3 months old, it is not a video of decades ago, with which the motorcycles that are from past decades.
The video is the recording of the motorcycle refueling authorized by the Venezuelan government for a single day and a certain amount of motorcycle fuel.
In these circumstances, the motorcycle it suits more: a simple 4S carburettor or a sophisticated 2S TPI
The TPI can make the consumption equal to the 4S, but its price is a brake.

https://youtu.be/TkghVdvZenA

ceci

24th July 2020, 03:41

The true technological advance is the one that reaches the whole world, and not the one that reaches the lucky few

Flettner

24th July 2020, 07:58

The true technological advance is the one that reaches the whole world, and not the one that reaches the lucky few

Cost, imagine the cost if KTM had stuck to their DI.
TPI should be no more expensive ( cheaper in fact ) than a fuel injected fourstroke.

Norman

24th July 2020, 10:29

Cost, imagine the cost if KTM had stuck to their DI.
TPI should be no more expensive ( cheaper in fact ) than a fuel injected fourstroke.

I see that TM-Racing is using F-TPI on some of their 2-stroke enduros. And claims meeting EURO4 emissions.

Flettner

24th July 2020, 12:57

I see that TM-Racing is using F-TPI on some of their 2-stroke enduros. And claims meeting EURO4 emissions.
All things being equal, I should have one of those soon. I will report on its efficiency.

WilDun

24th July 2020, 20:51

All things being equal, I should have one of those soon. I will report on its efficiency.

So I guess we should just wait and see ..... if we are all patient, things will become much clearer as to what is actually happening and speculation will no longer be necessary!- whatever the answer really is, I hope it'll eventually be a step in the right direction towards making the two stroke respectable again!

Pursang

25th July 2020, 11:25

Now that Ken has posted pictures of the new version of the head for his UHV System (Well done Ken!:niceone:) I want to post my thoughts on reverse uniflow.

After my rejection of poppet valves on the grounds of weight & complexity, Ken's working demonstration of reeds in the squish was a Revelation.:eek5:
Engine speed, cam driven valves might offer significant efficiency improvement over 4 strokes, but with a high level of mechanical complexity.
A real 2 Stroke (even a Clean, Modern one) should have a minimum of moving parts.

Many reverse uniflow engines use external pumps to 'push' the exhaust out of the cylinder, with the risk of over scavenging and allowing fresh charge to escape.
Others have attempted to create a Uniform Slug of fresh mixture to do the same, with the same result of charge escape.

My proposal is: Rather than trying to 'push' the exhaust out with the fresh charge, concentrate on directing charge Into the combustion chamber.

Advantages:
A) Purest (undiluted) charge for next ignition, (At all engine speeds, and throttle openings), so no 4 stroking, failed cycles.
B) Coolest chamber temp, so can run higher comp & engine operating temp (aiming for as adiabatic as possible)
C) Stratification of the charge (allows High comp / lean Burn / fast combustion) see F) below.
D) The chamber overflow can just 'follow' the exhaust down the cylinder. Exhaust porting configured for 'even escape' (3 or more ports)
E) Depending on throttle opening, engine speed and cylinder bore/stroke and exhaust config, reed area & rate, charging could be timed to Stop (just) before EPC,
F) Compression stroke will compress and mix the diluted & heated charge and any residual exhaust up against the 'full' chamber (C)for 'enhanced' ignition by A).

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Undoubtably, there will be significant Flaws in my reasoning! :bs: But this is the best forum to thrash them out.:girlfight: or Discuss like Gentlemen!

Cheers, Daryl.

WilDun

25th July 2020, 13:53

Now that Ken has posted pictures of the new version of the head for his UHV System (Well done Ken!:niceone:) I want to post my thoughts on reverse uniflow. .........................
Many reverse uniflow engines use external pumps to 'push' the exhaust out of the cylinder, with the risk of over scavenging and allowing fresh charge to escape.................

There are a few ways of controlling this by things like asymmetric timing of the exhaust (talking uniflow here of course)

Others have attempted to create a Uniform Slug of fresh mixture to do the same, with the same result of charge escape.

Not so sure that the slug pushes it out, as its momentum (when it is released will continue to drag everything out through a (straight) pipe!
This could make a hybrid type transmission become feasibile with an engine remaining in a narrow rev band and not requiring any changes in port timing,( once they are established) - ironically, this layout would also be suitable for a chamber too (designed to suit this particular rev band) - but as many of you know, I despise any chance of the two charges mixing - and chambers are good at that!!

there will be significant Flaws in my reasoning! :bs: But this is the best forum to thrash them out.:girlfight: or Discuss like Gentlemen!

Well, we are all gentlemen here! - and I don't think there are any girls! - (yes, yes I know, - "sexist bastard" ..... "armchair engineer").:rolleyes:

Pursang

25th July 2020, 15:15

Not so sure that the slug pushes it out, as its momentum (when it is released will continue to drag everything out through a (straight) pipe!

Yes, saying the transfer slug pushes the exhaust out was 'Pushing it'. Displacing residual combustion products might be a more accurate term.

Cheers,Daryl

breezy

25th July 2020, 18:32

maybe kens reed head could be configured to be used as exhaust port . like the opposed piston set up, keeping the exhaust phase away from the fresh charge.

WilDun

25th July 2020, 19:57

Yes, saying the transfer slug pushes the exhaust out was 'Pushing it'. Displacing residual combustion products might be a more accurate term.

Cheers,Daryl

Ok, let's just call it "chasing" !

husaberg

25th July 2020, 20:17

Yes, saying the transfer slug pushes the exhaust out was 'Pushing it'. Displacing residual combustion products might be a more accurate term.

Cheers,Daryl

Are you suggesting there is REPLACEMENT FOR DISPLACEMENT?

Pursang

25th July 2020, 20:59

Ok, let's just call it "chasing" !

'Chasing' sounds a little undignified and uncontrolled. :chase:

How about Herding...or Scavenging.

Cheers, Daryl.

Pursang

25th July 2020, 21:15

Are yo suggesting there is REPLACEMENT FOR DISPLACEMENT?

Mass Transfer by Volumetric Displacement is the Solution! (for those who don't believe that there is enough crankcase pressure to achieve transfer)

For those addicted to Displacement... there is always one of these----> 3 X 490!

346548

Cheers, Daryl

Flettner

25th July 2020, 21:16

A step closer to realising the 175cc single cylinder OP uniflow, in real hardwear.
Even if they do 'make a lot of noise', allegedly.
Notice the injector lugs on the cold end transfers, TPI.

Pursang

25th July 2020, 21:20

https://media1.tenor.com/images/2290cadd2f952ccd35abe5e6f7406c9c/tenor.gif?itemid=8934620

WilDun

25th July 2020, 23:27

Mass Transfer by Volumetric Displacement is the Solution! (for those who don't believe that there is enough crankcase pressure to achieve transfer)

For those addicted to Displacement... there is always one of these----> 3 X 490!

346548

Cheers, Daryl

Yep,
I see things starting to come together and work in harmony here - ie ideas, but also exhausts and transfers working in harmony ..........a few key pieces have now been placed in the jigsaw puzzle to make the big picture of the future two stroke a bit clearer! - hope that there's no lost pieces!

As for that monster engine in the picture - if you want to be a showman, just do it in a car!- things can be hidden under the bonnet! - great dirt track car! - would blow them all away, but check the gearbox often!

Neil - that is sure looking good, but I'll reserve judgment till (as I said above) the picture becomes clearer and there is some understanding of what to judge! ........... and there's Ken's project too - all looking good!

BUT ........... where is Haufen? - we haven't heard from him since he started the thread !!..... is he ok?

ken seeber

26th July 2020, 16:02

That’s Dazzling Dazza

I do like the basics of you proposal and I think we’re all talking the same language here:

Getting the fresh charge into the combustion chamber, but, in whatever way we want to describe it, get a descending slug of the remaining mixture, to pass down the cylinder, displacing exhaust gas and also not getting lost out the exh port. Or at least, if it does pass out, then it is returned (by wave action).

Neil’s OP has a fundamental advantage in that he has effectively a cylinder which is twice as long as the UHV. Giving him a greater possibility of maintaining the magical slug. Another advantage is that the porting is asymmetric, lots of radial transfers and, also the 3 exh ports, whereas I am currently dealing with just one exhaust port.
Fundamentally, I think a more undersquare layout with symmetrical exhausts could only be beneficial.

Certainly wish Fletto the best with his OP, he has put a shitload of hard work & passion into it.

For me on the case with the next version of UHV. In this case, I am trying to create a flow towards the comb chamber, but also across and downwards, essentially in the opposite direction of the usual Schnurle flow direction. Also hopefully with the two outer tangential flows colliding and cancelling out some downwards velocity.

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For all these UHV valves to date, I am using a 0.2 thick material over a Ø5 hole with a 2 wide perimeter, so therefore each blade cannot be less that 9. As I cast up a few blank heads, I intend to try a squishless version, ie a single flat & circular combustion chamber of bore diameter.

But back to Dazza’s concept. I actually love it and did consider some form of individual petals, radially disposed, but only on a flat head face. One issue being achieving enough lift without overstraining the flexure part of the petal attachment.

346562.

But angling the petal sealing surface, say at a conventional squish angle, directing the charge to the bowl is really nice. How this is done is the issue. Spherically shaped petals or a series of angled flats. And then tolerancing the petals to seal. Lots of clever guys out there.

Pursang

27th July 2020, 01:20

Thanks for the kind words Ken, really I'm just looking over you shoulder.

I like your new head, years ago I spent some time investigating improvements to Flathead 4 strokes.
They can be way better than most people expect.

In my proposal, the radial reeds and exhaust ports are an attempt to eliminate or minimise any Schnuerley flows.

For a prototype, build at home, I would be machining flats in the head for each reed to seat on.

Compound curved reeds? spoons? might be a way down the track.
There is also a possibility that actual reeds aren't required.
Flow & pressure differential controlled 'flap valves' might be an option.

Re: bore and stroke ratios, I think there will be a balancing act between these.
A narrow bore reduces your transfer area (A high tapered squish angle gets some back).

I think exhaust duration will be a key factor as the transfer obviously cant begin until sufficient blowdown is achieved.
It will be possible though for it to continue until around EPC.

Cheers, Daryl.

Frits Overmars

27th July 2020, 01:42

A narrow bore reduces your transfer area.You may want to give this a bit more thought Daryl.
If you wish to maintain the original cylinder capacity, halving the bore will require quadrupling the stroke, which will double the transfer area as well as the transfer area per cc.

If you want to maintain the original stroke, halving the bore will mean dividing the cylinder capacity by four, and since the transfer area is proportional to the halved bore, multiplied by the original stroke, this transfer area will only be halved and the transfer area per cc will once again be doubled.

WilDun

27th July 2020, 08:42

You may want to give this a bit more thought Daryl.
If you wish to maintain the original cylinder capacity, halving the bore will require quadrupling the stroke, which will double the transfer area as well as the transfer area per cc.

If you want to maintain the original stroke, halving the bore will mean dividing the cylinder capacity by four, and since the transfer area is proportional to the halved bore, multiplied by the original stroke, this transfer area will only be halved and the transfer area per cc will once again be doubled.

Ok, but does the introduction of a supercharger make any difference to this already complicated (to some of us) scenario?

ceci

27th July 2020, 10:14

If you want to maintain the original stroke, halving the bore will mean dividing the cylinder capacity by four, and since the transfer area is proportional to the halved bore, multiplied by the original stroke, this transfer area will only be halved and the transfer area per cc will once again be doubled.

This is applicable in the opposite direction.
"Schnuerley". It allowed machines that started in 1945 with a bore of 45.6 mm and a stroke of 60 mm = 98cc, due to the use of a piston with baffle and limitation of the transfer area.
They will increase their capacity at the same time as their performance B 60 mm and S 60 mm = 174.77 cc, increasing up to B 72.5 mm and S 60 mm = 247.69 cc.
It was not only an increase in capacity, but also an increase in the transfer area.

https://upload.wikimedia.org/wikipedia/commons/b/bf/Bore_Stroke_Ratio_Animation.gif

Pursang

27th July 2020, 11:30

Hi Frits, thanks for your input in this less Racey section.

You may want to give this a bit more thought Daryl.
If you wish to maintain the original cylinder capacity, halving the bore will require quadrupling the stroke, which will double the transfer area as well as the transfer area per cc.

If you want to maintain the original stroke, halving the bore will mean dividing the cylinder capacity by four, and since the transfer area is proportional to the halved bore, multiplied by the original stroke, this transfer area will only be halved and the transfer area per cc will once again be doubled.

For regular transfer ports, for sure!

But, Under Head or Squish Reed transfers are limited to the Squish area.
Halving the bore reduces the available area by factor of 4
So, 4 times Stroke for same cc = 4 times transfer velocity. Is this a Good or Bad thing? I don't know, testing required.

Cheers, Daryl.

Pursang

27th July 2020, 12:55

Ok, but does the introduction of a supercharger make any difference to this already complicated (to some of us) scenario?

Well, Ken has already demonstrated a Reverse Uni-flow 2 Stroke running without an external pump.

So, at this point a supercharger is just additional 'complication'. Boost would raise the HP potential, but also increase the likelihood of fresh charge escaping via the exhaust.

Plenty of development opportunity to create a 'clean' burning, case transfer, RUF engine by optimisation of bore/stroke, transfer port area, reed orientation and flex rate, exhaust configuration & duration, etc, etc. (Plenty of scope for TPI too!)

Of course, not all solutions are Mechanical!
If someone develops a smokeless 2 stroke Oil, that smells like fresh cooked donuts And extracts CO2 from the atmosphere we could all be riding Kwaka H1 Mach L's.:laugh:

Cheers, Daryl.

Norman

27th July 2020, 19:58

Well, Ken has already demonstrated a Reverse Uni-flow 2 Stroke running without an external pump.

So, at this point a supercharger is just additional 'complication'. Boost would raise the HP potential, but also increase the likelihood of fresh charge escaping via the exhaust.

Plenty of development opportunity to create a 'clean' burning case transfer RU engine by optimisation of bore/stroke, transfer port area, reed orientation and flex rate, exhaust configuration & duration, etc, etc. (Plenty of scope for TPI too!)

Of course, not all solutions are Mechanical!
If someone develops a smokeless 2 stroke Oil, that smells like fresh cooked donuts And extracts CO2 from the atmosphere we could all be riding Kwaka H1 Mach L's.:laugh:

Cheers, Daryl.

Triboron two stroke "oil" concentrate/oil injection. Might be an option? I still find that there are more independent test needed. Looking into for example on how it affects engine parts in the long run. But, find it interesting as much of the oil is taken out from the lubrication fluid. It is still too expensive but if used more widespread price should drop. This article gives an introduction by someone else than the company: https://www.zundappveteranenclub.nl/triboron/. However it does not smell fresh donuts :no:

ken seeber

27th July 2020, 20:49

Another top down approach, on the Fazebook "2 stroke R & D thread"

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Flettner

27th July 2020, 20:53

Another top down approach, on the Fazebook "2 stroke R & D thread"

346574

Interesting concept, mmm, fresh doughnuts.

Frits Overmars

27th July 2020, 23:16

Hi Frits, thanks for your input in this less Racey section. For regular transfer ports, for sure! But, Under Head or Squish Reed transfers are limited to the Squish area. Halving the bore reduces the available area by factor of 4. So, 4 times Stroke for same cc = 4 times transfer velocity. Is this a Good or Bad thing? I don't know, testing required.You're right about that Daryl, my mind got stuck at 'regular' piston-controlled transfer ports. For Ken's head-mounted transfer flippers, doubling the bore means quadrupling their cross-flow area, same as with the valves in the previous pre-turbo Formula 1 engines, which led to a bore of 98 mm, a stroke of 39,75 mm and a pancake-shaped combustion chamber that required over 50° ignition advance - not the best way to promote thermal efficiency...

If someone develops a smokeless 2 stroke Oil, that smells like fresh cooked donuts And extracts CO2 from the atmosphere we could all be riding Kwaka H1 Mach I's.Some time ago, when I was 15 years old, I greased my moped petrol with salad oil (freely obtainable when mum wasn't looking) for that lovely racy smell. Since then, smart entrepreneurs marketed two-stroke oil smelling of strawberries, so your donut smell shouldn't be a problem either. But why should it need to extract CO2 from the atmosphere. That's a job for trees, isn't it?

Another top down approach, on the Fazebook "2 stroke R & D thread"I haven't visited Fakebook yet today. As always, that will have to wait until I've studied all there is to study on Kiwibiker. But maybe you already took a peek here:
https://www.kiwibiker.co.nz/forums/showthread.php/171300-Oddball-engines-and-prototypes?p=1131167093#post1131167093
https://www.kiwibiker.co.nz/forums/showthread.php/171300-Oddball-engines-and-prototypes?p=1131167176#post1131167176

Pursang

28th July 2020, 00:46

Triboron two stroke "oil" concentrate/oil injection. Might be an option? I still find that there are more independent test needed. Looking into for example on how it affects engine parts in the long run. But, find it interesting as much of the oil is taken out from the lubrication fluid. It is still too expensive but if used more widespread price should drop. This article gives an introduction by someone else than the company: https://www.zundappveteranenclub.nl/triboron/. However it does not smell fresh donuts :no:

No smell at All! Sounds like a good idea. Has anybody out there had any practical experience with this or other non-oil alternatives?
50 euro/litre seem a bit expensive, but at 100:1 the Premium Petrol is still the major cost.
(Or compare with say, Castrol TTS at half the price, but double+ the mix)
Need a couple of manufacturers, in competition, to get the price down. Perhaps a patent or licensing agreement needs to lapse first!

Some time ago, when I was 15 years old, I greased my moped petrol with salad oil (freely obtainable when mum wasn't looking) for that lovely racy smell. Since then, smart entrepreneurs marketed two-stroke oil smelling of strawberries, so your donut smell shouldn't be a problem either. But why should it need to extract CO2 from the atmosphere. That's a job for trees, isn't it?

Yes Frits, CO2 consumption is a job for trees. If only we would let them grow faster than we cut & bulldoze them down.

I just like the idea of getting a 'green grant' and being subsidised to save the world by riding big, old, 2 stokers about! Win Win :ride:

Cheers, Daryl.

Niels Abildgaard

28th July 2020, 04:10

Another top down approach, on the Fazebook "2 stroke R & D thread"

346574

It is a Schliha scavenge system used in motorbikes 1929 and an aircraft 1935 (Erla6)
It had the eternal two stroke problem of using piston for controling exhaust,but in this case it is at least symmetrical around cylinder.
The only two-strokes still being best for job today has one exhaust valve per cylinder.

WilDun

28th July 2020, 09:07

I'm told that the Chainsaw wielding lumberjacks in Oregon, Canada etc. actually use cooking oil exclusively in their chainsaws - can't remember for sure what kind (might've been Canola) - someone here will know! (possibly only for chainbar lubrication though!).

Update:- Ok. have a look here anyway, this guy seems sensible - Scroll forward to 25 or so and get to the Canola (Rapeseed oil) part.
https://www.youtube.com/watch?v=UqbjQ2DOlIo

But ..... burnt oil, (vegetable or whatever!), is pollution!

Norman

28th July 2020, 10:00

WilDun

28th July 2020, 10:51

Nice new retro street legal two stroke bike on the market. EURO 4 emission approval..just in time.!?
The injectors are positioned right in the center of the reed valves. The 250cc Vins engine.

https://langenmotorcycles.co.uk/the2stroke/

Looks good! - and it is a two stroke!! - seems like one step in the right direction.
If it's as good as the website, it is good! - and now, how good is the price?
Should be cheaper than a four stroke, shouldn't it?? - (much more simple and cheaper to make ??)..... well, no maybe not ..... "cool" ...."sports".

How about a nice little commuter version based on that and sell them (X 10)? and re-establish the two stroke on the roads! (all in the interest of keeping 2T bucket racing on the track and consequently ESE thread of course)!!!

Pursang

28th July 2020, 11:05

Nice Spec, I would ride that......Except I'm obviously Way Not Cool enough!:(

I just cant possibly bring myself to ride without my helmet fastened.

https://langenmotorcycles.co.uk/wp-content/uploads/2020/06/Biker-Helmet-Retro-GK4RFG.jpg

Cheers Daryl.

Pursang

28th July 2020, 11:57

Update:- Ok. have a look here anyway, this guy seems sensible - Scroll forward to 25 or so and get to the Canola (Rapeseed oil) part.
https://www.youtube.com/watch?v=UqbjQ2DOlIo

But ..... burnt oil, (vegetable or whatever!), is pollution!

That saw was certainly working hard. It would be interesting to see some long term testing of 2 strokes on Canola.
Of course, at Au$2.40/L ( that's like 2c US or EU 0 ), there is no money in it for any real business to bother with. :oi-grr:

Burnt oil is pollution, but you get lots of 'Green Points' for burning renewables and not dinosaurs. Bio Diesel, Biogas, Bio 2-stroke!:innocent:

Cheers, Daryl.

Flettner

28th July 2020, 12:00

Pursang

28th July 2020, 12:03

Interesting concept, mmm, fresh doughnuts.

Double ended donut punch?....;)

Flettner

28th July 2020, 12:04

Daryl, I agree, Ethanol fuel for me too, no more petrol in my new builds.
My F9 runs so well on E85 why bother with anything else, whats detonation?

Pursang

28th July 2020, 12:06

Cylinder bolted up to the old set of cases.

Your Productivity is Embarrassing to mere mortals!:o

WilDun

28th July 2020, 12:09

Cylinder bolted up to the old set of cases.
Yes it going to be a tall engine alright, but it will fit in the YZF 250 frame. Good enough to be a technology demonstrator. Next one will lay much flatter with the gearbox and clutch wrapped around the cylinder.

Yes, we'll let you off regarding the height - we understand!
The transfers do intrigue me but seem quite sensible, especially if there is no longer any "Schneurle" involved! - but the injector bill is going to be colossal! .... unless you settle for every other port! ?? (of course I could have totally got the wrong end of the stick!).

Flettner

28th July 2020, 12:13

Your Productivity is Embarrassing to mere mortals!:o

Ive got something to prove and this is the only way I know how.
And I gave my YZ away to my daughter so now all I've got is a big old TT500 to ride, or it rides me. So its hell for leather to get another trail bike up and running. Just it will be a bit different.
Could always get the mk2 TPI 360 running, its still just sitting on the dyno. With a cover over it. I am suitably ashamed of myself.

Flettner

28th July 2020, 12:16

Yes, we'll let you off regarding the height - we understand!
The transfers do intrigue me but seem quite sensible, especially if going straight across (ie not raised, - 0 deg and not tangential) but the injector bill is going to be colossal! .... unless you settle for every other port! ??

The transfers are one of the key elements of this new design, three will have injectors, three not.

WilDun

28th July 2020, 13:38

The transfers are one of the key elements of this new design, three will have injectors, three not.

:niceone: ..........

BTW, as you appear to be still going to use crankcase pumping, how will you be transferring air from the exhaust cylinder ("pump") to the cylinder "transfer" ports - I mean, will it be pumped into the other crankcase first? ..... or is that classified info?

Flettner

28th July 2020, 15:24

:niceone: ..........

BTW, as you appear to be still going to use crankcase pumping, how will you be transferring air from the exhaust cylinder ("pump") to the cylinder "transfer" ports - I mean, will it be pumped into the other crankcase first? ..... or is that classified info?

It is, Will D.

Flettner

28th July 2020, 19:14

On to the pistons next, special shape and composite construction. 48mm dia.
Im just useing two times AG 100 cranks and KT 100 rods, as I have them. 48mm stroke.

WilDun

28th July 2020, 19:38

On to the pistons next, special shape and composite construction. 48mm dia.
Im just useing two times AG 100 cranks and KT 100 rods, as I have them. 48mm stroke.

Both pistons the same construction? - guess they'll be designed able to stand combustion heat better! - no doubt it'll all become clear soon!

Flettner

28th July 2020, 21:11

Both pistons the same construction? - guess they'll be designed able to stand combustion heat better! - no doubt it'll all become clear soon!

Um, no. Hot piston and cold piston will be different construction. Cold one will be semi traditional, hot one, space age. To not accept heat, help transfer heat that does get in, not expand unfavorably and not glow red hot to promote detonation.
Although some control of this may help HCCI in the future.

WilDun

28th July 2020, 21:29

Um, no. Hot piston and cold piston will be different construction. Cold one will be semi traditional, hot one, space age. To not accept heat, help transfer heat that does get in, not expand unfavorably and not glow red hot to promote detonation.
Although some control of this may help HCCI in the future.

That's great, but I won't bug you about all the details - glad to hear that HCCI is still somewhere around though - I was just thinking the other day and wondering if it had been tossed in the "too hard basket" (by everyone).
Mazda's effort doesn't seem to be raising peoples' enthusiasm much and anyway most people who buy vehicles wouldn't notice, care or even be slightly interested if it was powering their vehicles or not - they'd be much more interested in looking cool and checking whether the seat colours matched the steering wheel! - what the bloody hell are we becoming?

Pursang

29th July 2020, 00:36

hot one, space age. To not accept heat, help transfer heat that does get in, not expand unfavorably and not glow red hot to promote detonation.
Although some control of this may help HCCI in the future.

In the interest of Green, Environmentally Sensitive & Responsible 2 strokes, are you going to be Sequestering some Carbon in the hot piston structure?...:shifty:

Cheers, Daryl.

ceci

29th July 2020, 09:37

Is it a step forward or is it a step back?
Peugeot already marketed the TSDI that used Orbital technology.
Because now it changes to Low Pressure Direct Injection system (LPDI)

https://www.motoservices.com/actualite-50/Gamme-Peugeot-2019-les-scooters-50-cm3-2-temps-injection-sont-la-oct-2018.htm

https://media.motoservices.com/media/cache/fullscreen_gallery/media/gallery/12353/IMG_3796.JPG

Pursang

29th July 2020, 11:43

Is it a step forward or is it a step back?
Peugeot already marketed the TSDI that used Orbital technology.
Because now it changes to Low Pressure Direct Injection system (LPDI)

Slippery Step Sideways!

Large manufactures are always looking for the lowest cost solution that will achieve whatever minimum standard is required by legislators.

Save $a per unit x bb,bbb units = More $ for Directors bonuses!....:msn-wink:

On a technical note, they are injecting into/across the boost port flow, to get it up the top and keep well away from the exhaust. Good idea.
Hard to tell, but they could also inject back into the crankcase through a boost window in the piston??...perhaps for Maximum rpm, high demand situations.
A really cynical person might think it's a duel compliance system (ala VW). None of those people around here!

Cheers, Daryl.

ceci

29th July 2020, 19:47

Slippery Step Sideways!

Large manufactures are always looking for the lowest cost solution that will achieve whatever minimum standard is required by legislators.

Save $a per unit x bb,bbb units = More $ for Directors bonuses!....:msn-wink:

On a technical note, they are injecting into/across the boost port flow, to get it up the top and keep well away from the exhaust. Good idea.
Hard to tell, but they could also inject back into the crankcase through a boost window in the piston??...perhaps for Maximum rpm, high demand situations.
A really cynical person might think it's a duel compliance system (ala VW). None of those people around here!

Cheers, Daryl.

Hi Daryl.

The LPDI may be a rival to the TPI?.
Sherco and Beta have shown interest in this type of injection, they will get to market it now that Peugeot is going to do it

https://e-l.unifi.it/pluginfile.php/440948/mod_resource/content/1/SI-2T_LPDI.pdf

Norman

29th July 2020, 23:40

Hi Daryl.

The LPDI may be a rival to the TPI?.
Sherco and Beta have shown interest in this type of injection, they will get to market it now that Peugeot is going to do it

https://e-l.unifi.it/pluginfile.php/440948/mod_resource/content/1/SI-2T_LPDI.pdf

Interesting presentation!
LPDI Injection under the piston can give a stratified push through the boost port, if that works it is quite an advantage if it really works. Can also increase the application to really high performance/RPM applications?
As I understand it PFI will not get the PM emssions legislation under EURO5, but DI will. So maybe TPI is still competitive not at least only for this reason, if the HC can be kept under control.
What is the best solution or combination of solutions, for the highest performance applications using +9-1000k RPM? To avoid injecting fuel into crankcase that then ends up in the A-ports? Because a tuned exhaust will not be able to push all the short cut air-fuel bacK? If we look at EURO 5 it is very tough on HC emissions..

Pursang

30th July 2020, 00:13

Yes Interesting Presentation,
Much more of a Sales Brochure than a technical paper.

The Peugeot FI seems to be based on the Graz design rather than the Forentina

346597

Cheers, Daryl

Pursang

30th July 2020, 00:21

LPDI Injection under the piston can give a stratified push through the boost port, if that works it is quite an advantage if it really works. Can also increase the application to really high performance/RPM applications?

Yes, looks like that. Depending on the volume of fuel injected under the piston, much of it might remain there, trapped by the down stroke. It could cool the piston and small end and return back through the window into the boost port.

Cheers, Daryl.

Norman

30th July 2020, 04:16

Yes, looks like that. Depending on the volume of fuel injected under the piston, much of it might remain there, trapped by the down stroke. It could cool the piston and small end and return back through the window into the boost port.

Cheers, Daryl.

Have a feeling that F-TPI, if injected during transfer flow, have more time and is better splitting up the fuel into smaller droplets using the transfer counterflow.

Vannik

30th July 2020, 06:43

Neil,

Your YZ250 is mentioned in this video but they do not know what became of it - maybe somebody should put them straight on where TPI comes from?

https://www.youtube.com/watch?v=R1yLUF3aHxQ

Flettner

30th July 2020, 08:51

He's too hard to get hold of. I've left a comment so lets see what happens? I have commented in the past but never had a reply.

Anyway TPI is old news now, OP uniflow is where it's at now. Id fit an emoji here but my phone doesn't seem to allow it. Smiley face.

WilDun

30th July 2020, 09:55

Yeah, it's pretty soul destroying to see your baby being swept up and carried away in a flood of hype and bullshit and becoming something of a novelty when it is suddenly "discovered" by someone else (not always in a malicious way - sometimes just in ignorance) and developed further!

A typical case is John Dunlop (actually a Vet) who thought he had come up with something new (pneumatic tyre) when in fact someone else, a countryman of his, had already tried it fifty years or so earlier! - his reply was that if he had known that, he wouldn't have bothered! - however, as we all know today he was successful - he then sold his company early and lived a very comfortable life!

Guess that is why we have patents, but then maintaining those patents becomes a separate mission in itself and needs a lot of specialist people around and so it balloons way out of the enthusiast's reach and ends up in the arms of some rich patent collector, who either puts it up for sale or stores it in his back room to wait for the right moment to re-introduce it!

I believe that many true inventors have experienced the same thing.

And then ..... I could be talking crap! :rolleyes:

Flettner

30th July 2020, 16:39

https://youtu.be/MuvJIoUTA8k

ceci

30th July 2020, 19:40

A typical case is John Dunlop (actually a Vet) who thought he had come up with something new (pneumatic tyre) when in fact someone else, a countryman of his, had already tried it fifty years or so earlier! - his reply was that if he had known that, he wouldn't have bothered! - however, as we all know today he was successful - he then sold his company early and lived a very comfortable life! :

Is wrong with evolving or developing projects abandoned by others?.

Guess that is why we have patents, but then maintaining those patents becomes a separate mission in itself and needs a lot of specialist people around and so it balloons way out of the enthusiast's reach and ends up in the arms of some rich patent collector, who either puts it up for sale or stores it in his back room to wait for the right moment to re-introduce it! :

Even the most ridiculous of projects carried out by simple inventor, ends up being patented by large companies that have no relationship with the inventor

WilDun

31st July 2020, 00:45

Is wrong with evolving or developing projects abandoned by others?.

No, that's how it is!

Even the most ridiculous of projects carried out by simple inventor, ends up being patented by large companies that have no relationship with the inventor

Yep - sad but true!

Neil, It's much bigger than I thought it was going to be! and I thought it was going to take longer to do! ......... do you really think you can get it in a bike? - all those years of hard slog in your workshop have sure taken a toll on you! ;)

katinas

31st July 2020, 04:33

Some time ago, when I was 15 years old, I greased my moped petrol with salad oil (freely obtainable when mum wasn't looking) for that lovely racy smell. Since then, smart entrepreneurs marketed two-stroke oil smelling of strawberries, so your donut smell shouldn't be a problem either. But why should it need to extract CO2 from the atmosphere. That's a job for trees, isn't it?

This fun story is reminiscent me youthful times too, when it was very difficult to find proper oil for 2t in Soviet land. Only rarely, I don't know how, it was possible to find an aviation synthetic oil MC 20.
But once, by accident, I read that red drum brake fluid BSK, consists of 50 percent butyl alcohol and 50 percent refined castor oil and it was sold in all auto stores in packs of 1 liter!!! The smell of butanol was awful, but exhaust ..........
Nowadays, it is still used in tractors, but in plastic package.

Add pic of 1982 patent very similar to DiTech and other............most complicated two stroke piston.

ceci

31st July 2020, 05:47

Add pic of 1982 patent very similar to DiTech and other............most complicated two stroke piston.

Hi Katinas

You can put more images of the patent of the pneumatic injection system. Thank you

Flettner

31st July 2020, 08:07

Neil, It's much bigger than I thought it was going to be! ;)[/QUOTE]

HA HA, yes, not something Im proud of.

I've used 100mm rods for a 48 stroke and the cranks are just standard AG 100 units. If I got serious I'd optimise all these components for size and I've got plenty of room to drop the bottom crankshaft lower, next time. I just want it up and running for evaluation. There is also plenty of room up top as the frame is a perimeter type. It will fit.

Flettner

31st July 2020, 08:14

Katinas, those spherical sealing rings intetest me, last picture. On the outside pushing in to seal. I wonder how much real world work has been done on this.

WilDun

31st July 2020, 09:55

Sure is complicated! - and throwing a rod would be a major catastrophe!! - there are so many problems already with small end bearings and conrod failure, it's hard to imagine how all those parts would fare at 10,000 revs!
But nevertheless, its clear that there has been a lot of thought gone into it! - and the cam idea - great!
(what the hell is it anyway? :blink: :confused:) ......... :msn-wink:

Katinas - That stuff sounds almost drinkable! - if they changed it to Ethanol instead, sales would go up by 100%! - but I must say that way back in the day, half of the enthusiasm for racing machinery came from the beautiful aroma of burnt Castor oil!

TZ350

31st July 2020, 11:20

Neil,

Your YZ250 is mentioned in this video but they do not know what became of it - maybe somebody should put them straight on where TPI comes from?

https://www.youtube.com/watch?v=R1yLUF3aHxQ

I have added a few links on their YouTube page to Flettners EFI bikes.

<ytd-expander id="expander" max-number-of-lines="4" class="style-scope ytd-comment-renderer" should-use-number-of-lines="" style="display: block; --ytd-expander-button-margin: 4px 0 0 0; --ytd-expander-max-lines:4;"><yt-formatted-string id="content-text" slot="content" split-lines="" class="style-scope ytd-comment-renderer" style="white-space: pre-wrap; --yt-endpoint-color: var(--yt-spec-call-to-action); --yt-endpoint-hover-color: var(--yt-spec-call-to-action); --yt-endpoint-visited-color: var(--yt-spec-call-to-action); color: var(--yt-spec-text-primary); font-size: var(--ytd-user-comment_-_font-size); font-weight: var(--ytd-user-comment_-_font-weight); letter-spacing: var(--ytd-user-comment_-_letter-spacing); line-height: 2rem;">First startup 7 years ago. Well before KTM:- https://youtu.be/hOGZ5llowoU
On the Dyno:- https://youtu.be/UEQli7nuak4
And an old F5 Kawasaki converted to EFI:- https://youtu.be/eleqBGvOM4M</yt-formatted-string>
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husaberg

31st July 2020, 18:46

This fun story is reminiscent me youthful times too, when it was very difficult to find proper oil for 2t in Soviet land. Only rarely, I don't know how, it was possible to find an aviation synthetic oil MC 20.
But once, by accident, I read that red drum brake fluid BSK, consists of 50 percent butyl alcohol and 50 percent refined castor oil and it was sold in all auto stores in packs of 1 liter!!! The smell of butanol was awful, but exhaust ..........
Nowadays, it is still used in tractors, but in plastic package.

Add pic of 1982 patent very similar to DiTech and other............most complicated two stroke piston.

Lkely sold the rest of the hulls to the KGB .

Flettner

31st July 2020, 19:17

katinas

31st July 2020, 22:49

Ceci, there is no other scheme, only that one. I can add a translation, but I think everything is clear form scheme.

Flettner, there is no any explanation about spherical sealing rings construction.
Add simpler working example, with piston reed type and head reed type engine. Reed type piston test, shows poor organization and direction of the fresh charge flow in the working space of the engine cylinder. Surprisingly, steel reed petals not overheat, because of fresh mix flow.
And another complicated type, with exhaust in head.

WilDun, this red is breathable, even now, as I remember this red liquid, I immediately feel dizzy.

ceci

1st August 2020, 00:38

Ceci, there is no other scheme, only that one. I can add a translation, but I think everything is clear form scheme.

Thanks Katinas , you don't need to translate the text, the outline is already vastly explicit

Norman

1st August 2020, 06:38

A pair of cases just cast. I cheated, I took the molds to a foundry in town and got them to just pour them for me. I've run out of E85 for my furnace. I have some more fuel turning up next, old, car race fuel, that will do me.

Looks good. So we are looking at the base parts for an OP engine with F-TPI, Variable Rotary inlet valve, good control over exhaust and scavening flows and maybe an RPM range with potential HCCI..Well, is that not a good base for a clean efficient two stroker..!?
Some good exhaust after treatment solutions from the experts from that side and you have a good concept there, very good I think..And from there on some tweeking with space optimization.

ken seeber

2nd August 2020, 14:51

So much fun so long ago.
Wasn't 25 cars, it was 100.

https://www.whichcar.com.au/features/why-the-australian-orbital-two-stroke-engine-never-took-off

One positive fall out from the programme was that there were 100 brand new engines and gearboxes stored away on pallets. Shortly after, there were only 99. Still got it.

346630346631346632

Now, back to 2 strokes.

ken seeber

2nd August 2020, 15:05

Surprisingly, steel reed petals not overheat, because of fresh mix flow. .

Katinas, lots of amazing stuff. Just confirms yet again, whatever you think of, someone almost certainly has done it before.

Have to agree with you on reed petals not overheating, but have to admit only with limited running.

346633346634

husaberg

2nd August 2020, 15:14

Katinas, lots of amazing stuff. Just confirms yet again, whatever you think of, someone almost certainly has done it before.

Have to agree with you on reed petals not overheating, but have to admit only with limited running.

346633346634

Some pulse jets used Reeds. I am pretty sure the operating temp will be lower than a pulse jet. Although the intake air as well wil cool these too.
although they original ones only needed to run long enough to go from France across the channel.
here is some ocker.
punching.......................................... .................................................. ................................. Electrochemical etching

https://www.youtube.com/watch?v=g31CE-1AZgo
https://www.youtube.com/watch?v=jEnNMTMZadw

WilDun

2nd August 2020, 17:13

[QUOTE=husaberg;1131167512]Some pulse jets used Reeds. I am pretty sure the operating temp will be lower than a pulse jet. Although the intake air as well wil cool these too............................
Electrochemical etching/QUOTE]

Think that guy demonstrating how to make reeds is a (pretty feisty) Kiwi from Tokoroa! - well up in the model aircraft scene!

Ken,
I am interested in seeing how your scheme works and I don't think that the reeds will overheat but could they possibly hit the piston at certain revs?

Guess you won't be giving back the "lost" property you found anytime soon? - ;)

ken seeber

2nd August 2020, 19:37

Flettner

2nd August 2020, 20:03

Katinas,
My intetest is spherical seals. I did purchase some cast iron to make a housing but this project is way down the line.

husaberg

2nd August 2020, 20:06

Some pulse jets used Reeds. I am pretty sure the operating temp will be lower than a pulse jet. Although the intake air as well will cool these too............................
Electrochemical etching

Think that guy demonstrating how to make reeds is a (pretty feisty) Kiwi from Tokoroa! - well up in the model aircraft scene! ;)

Hoosa,
Dunno whether old mate is a kiwi or an ozzie (well, he had the right Tee shirt), but it was pretty good info. Especially so as my mate, who does the wire cutting, finishes up at the end of Nov. Thank you C19. Just a bit of Saxa salt, a 12V charger, cuppla light bulbs and 20 hours and you're done. Cheers for that one.

first guy is the ocker second one sounds like he's a Kiwi.
It seem like a pretty good way to cut fiddly stuff.

katinas

2nd August 2020, 20:32

Ken, anyway, it would be good to use high temp resistant chrome-moly steel (A387- 16Mo3 or VDM® Alloy 120) for petals, of course if it’s possible to get.
Remember old study days spending in library with all types of magazines and books, with every info about two stroke. One of the magazines was an East German KFT, sometimes with a lot of information from other world.
Still remember picture of MZ cylinder with additional exhaust port located on the opposite side of main exhaust, but connected through long channels around cylinder with main exhaust.

breezy

2nd August 2020, 21:18

how opposed do the pistons have to be? with the height issue? https://oldmachinepress.com/2014/02/24/michel-opposed-piston-diesel-engines/

WilDun

2nd August 2020, 21:34

Hoosa,
Dunno whether old mate is a kiwi or an ozzie (well, he had the right Tee shirt), but it was pretty good info. Especially so as my mate, who does the wire cutting, finishes up at the end of Nov. Thank you C19. Just a bit of Saxa salt, a 12V charger, cuppla light bulbs and 20 hours and you're done. Cheers for that one.
Wil,
We have this thing in Oz called the "statute of limitations" where paperwork, tax receipts etc don't have to be withheld for longer than 7 years = safe.

KEN,
Think this is what I was remembering, :- http://www.stuff.co.nz/waikato-times/10224044/Drone-testing-at-airfield-shot-down

OK, if you can prove that you've had it more than 7 years, we'll OK it! :niceone:

ken seeber

3rd August 2020, 19:58

One doesn't feel too bad when you might consider adding a few injectors or a valve onto a 2 stroke :weird:

346647346648

ceci

4th August 2020, 01:40

One doesn't feel too bad when you might consider adding a few injectors or a valve onto a 2 stroke :weird:

346647346648

Instead, I think the opposite, which should not be added, what should be done is to simplify what is already there. What there is is good, but if it is simplified we will do it twice as good.
That is why I have dismissed the DI concept as the only solution and start focusing on SDI.
I want to evolve the QUB Hill and Blair concept (it's like a TPI but without the electronics)

Flettner

4th August 2020, 21:27

Instead, I think the opposite, which should not be added, what should be done is to simplify what is already there. What there is is good, but if it is simplified we will do it twice as good.
That is why I have dismissed the DI concept as the only solution and start focusing on SDI.
I want to evolve the QUB Hill and Blair concept (it's like a TPI but without the electronics)

Is having an ecu on board such a bad thing?
Ecu with injectors can do a lot that a carburetor can not, way more fuel control and some interesting engine control too.

Frits Overmars

4th August 2020, 21:44

Is having an ecu on board such a bad thing? Ecu with injectors can do a lot that a carburetor can not, way more fuel control and some interesting engine control too.I remember the last carbureted Honda cars. In order to make those carburetors behave as required under all circumstances, they had become incredibly complicated.
Yet their ECU-controlled injected successors were better in every way and possibly cheaper as well. Mechanically-controlled injection certainly wouldn't have been...

ceci

4th August 2020, 23:15

Is having an ecu on board such a bad thing?
.

It is expensive and heavy, since it is not only the ECU but also the sensors, pump, injectors, battery and others.

Mechanically-controlled injection certainly wouldn't have been...

Not to be necessarily mechanical

Frits Overmars

4th August 2020, 23:26

Not to be necessarily mechanicalIf you do not control the injection electronically and not mechanically, then what else is there? Just a pump coupled to engine rpm? Surely that won't do.
(With 'mechanically' I meant 'with moving parts' , like a centrifugal governor, a pressure-sensitive bellow, a springloaded hinge moved by air flow, etc.)

ken seeber

4th August 2020, 23:31

Ceci,

I do like the Blair simplicity as much as I do like the Husqvarna X-Torq. Essentially incorporating some clever separation and re-routing of the scavenge system without much extra hardware. However, I just don't know if, for instance, this was applied to a bike, could this get anywhere near Euro 4 or 5.

I posted the BMW cylinder head as an example of the lengths that manufacturers are going to meet driveability, performance and also meet emission goals. I was just amazed at the complexity and number of fiddly components in the design. Yep, I'd hate to see that the 2 stroke has to go to such lengths to become clean, may just as well just go with volts and amps.

Personally, I do (unfortunately) think that we have to accept a greater level of complexity to become clean.

No misfiring for us.

ceci

5th August 2020, 04:53

If you do not control the injection electronically and not mechanically, then what else is there? Just a pump coupled to engine rpm? Surely that won't do.
(With 'mechanically' I meant 'with moving parts' , like a centrifugal governor, a pressure-sensitive bellow, a springloaded hinge moved by air flow, etc.)

You refer to this employee a century ago in Goliath CP 700 engine which is from Bosch.

https://media.springernature.com/full/springer-static/image/art%3A10.1007%2Fs35146-016-0133-1/MediaObjects/35146_2016_133_Fig3_HTML.jpg

In exchange I mean this Spanish (I know you understand Spanish, but I don't know if you know how to read it, that's why I will try to translate it "googletraslate" (The system is made up of three parts: two pumps, one of membranes (with carbon fiber sheets) and another line, and an injector.
The first is located behind the rear transfer of the cylinder and through a hole made in it sucks the gasoline from the tank taking advantage of the upward stroke of the piston. When it goes down, it creates a compression in the crankcase, from which a fitting emerges that drives the piston pump, located after the first pump and sends the mixture to the injector. This, coming from a kart carburettor with a carbon fiber guillotine, thus receives an injection of constant fuel, self-regulated by the engine rotation speed.
The whole secret of the operation of such a simple and ingenious system lies in the adequate calculation of the surfaces and diameters of the two pumps, to take advantage of the internal pressure and depression effects of the two-stroke engine.) )

https://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=346659&d=1538209875

It doesn't have to be a very bad idea when big companies have copied it,

https://patents.google.com/patent/US5197418?oq=Low+Pressure+Direct+Injection+two+str oke+engine

https://patentimages.storage.googleapis.com/fd/19/e1/bd32b0275dbf5e/US5197418-drawings-page-2.png

https://patents.google.com/patent/FR2737258A1/en?oq=Low+Pressure+Direct+Injection+two+stroke+eng ine

https://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=346660&d=1596559787

ceci

5th August 2020, 07:00

WilDun

5th August 2020, 10:05

I do agree that some complexity will be necessary for a clean machine, but when everything is established and working properly, then it isn't "complex" anymore! (only when it is new and and needing development).

Sure, go for simplicity if it is going to make a quantum leap, but even if it is a quantum leap, there will always be attempts at development to improve it further - and you have to keep up to survive ..... and so on it goes!

Of course, on the other hand, I have to admit that I've always been saying, the two stroke engine needs to be kept simple as possible, (using hybrid type transmission) which will then do away with the need for an incredibly flexible engine having to work perfectly over the whole rev range, but I'm not meaning a "spartan" thing without good fuel / charge management etc etc.!

My next crusade? get rid of Schneurle type transfer, expansion chamber and crankcase pumping! ........ OP? - Yes, (already proven to be efficient) - Turbo? - yes, I think so, (initially being spooled up by a motor for startup) - turbos are small and fast becoming a dime a dozen !

Yes we are matching emission requirements today, but they are continually raising the bar and one day our good old "normal" two stroke won't be able to keep up! - remember that realistically the two stroke in it's present form is hanging on by it's fingertips!

BTW, these suggestions are not all only my ideas, a lot of them come from ideas which I have gleaned from others here!

Anyway, that's how I see it! :rolleyes:

Then, last but not least ..... what has happened to Haufen? - the originator of the thread!

ceci

5th August 2020, 12:25

You will wonder why these types of injection systems were unsuccessful.

The Martin Clerch is an INDIRECT injection with which the short circuit and the loss of hydrocarbons by the exhaust are not avoided, it is also injected when there is no current, since when the piston falls if compression is created in the crankcase, but Yes No suck intake.

Stihl and Bosch are DI, which is not compatible with this type of pump as it pumps before TPO, and DI requires pumping after EPC.

In drawing 2, Bosch is more suitable for DI as it uses suction from the crankcase to pump

lohring

6th August 2020, 02:27

A long time ago the Rolls Royce Crecy used Bosh direct injection mechanical pumps like those used in diesel engines. The injection was timed to spray into the intake flow with a dribble into a prechamber to give a rich mixture at the plug. Throttling was bu varying the amount of fuel in the primary injection. It worked for aircraft applications but wouldn't have the power band for road applications. Mechanical injection pumps might be simple, but they require high precision manufacturing. Integrated circuits are complicated internally, but are made with much lower cost methods today. They have proved to be reliable and adaptable in automotive applications. Mass produced injectors and engine management electronics are readily available. Why not use them?

Lohring Miller

WilDun

6th August 2020, 21:06

A long time ago the Rolls Royce Crecy used Bosh direct injection mechanical pumps like those used in diesel engines. The injection was timed to spray into the intake flow with a dribble into a prechamber to give a rich mixture at the plug. ......................... Mechanical injection pumps might be simple, but they require high precision manufacturing. .................. Integrated circuits are complicated internally, but are made with much lower cost methods today. engine management electronics are readily available. Why not use them?

Lohring Miller

Electronics is here to stay, things which 20 years ago were an advanced idea, are now something which everybody uses (ho hum) - they do a good job and are seriously cheap - (but are we any happier?).

Let's look at a good example, the 3D printer, essentially a very simple machine which any engineer could construct easily.
This did not come into it's own till sophisticated electronic controllers and software to control the control hardware itself came into being, then suddenly it all blossomed and now every man and his dog has one - and what do they use them for ? - printing skulls and other grotesque "childlike" ornaments.
These things complete can currently cost under NZ $400!! - now they moan about these "crap machines" and expect perfection to be handed up on a plate! - this all being the sort of stuff we would have given our left arm for just a few years ago!

It's the same for motorcycles, use the old unsophisticated basic engine and adorn it with electronics to make it good to take on the road - but I think we have been caught napping this time and now have to work out a complete new design of "unsophisticated" engine to get going again!
Later on, the old "Ho Hum' thing and criticism if it's not doing what it's supposed to do will start all over again - (nobody really with any idea of what it's actually supposed to do, or how it works of course!), but that's how it is and only a few of us actually have any interest in or know how things work!

What I am saying is essentially what Lohring is saying, if it's been developed and it works well, it will get cheaper, it will serve us well (ie if we can adapt it for our uses) - all to our advantage!

Building a very (mechanically simple) machine however will get us in the ballpark!

lohring

7th August 2020, 03:48

Niels Abildgaard

7th August 2020, 07:01

ceci

7th August 2020, 07:53

Sorry, I forget that we are already in the 21st century and that we are in the middle of the space age.

The electronics can bring us infinity of advantages.

I forgot that Álex Debóm was a test pilot of the aprilia RS250 and in the preseason he tuned the carburetion (electronic carburetion with "powerjet" injection map for each section using GPS)

WilDun

7th August 2020, 10:41

Does this mean I need to get my dog a 3D printer. LOL I love mine for prototyping off the wall ideas. With the current (at least here) opposed piston two stroke fever, I'm inspired to join two of our RC engines into an opposed piston twin. The compact design will make a great speed record engine. I doubt that I'll worry about emissions, though.

Lohring Miller

Yes Lohring - get one for your dog as well, why not? at least it won't complain if it doesn't work perfectly!

When there's OP two stroke fever, then there's still life in the old dog (the two stroke) - so it aint dead yet!! ......... otherwise what else is there? :laugh:

Flettner

7th August 2020, 11:24

ceci, trouble is electronics are so accurite, both sensors and delivery. A box of infinitely adjustable electronic parts (ECU) are so cheap compared to the manufacture of mechanical injection parts. As well as the ability to pull 'tricks' that nothing mechanical can do.
Surrender to the dark side, you will. Smile Emoji.

Pursang

7th August 2020, 14:41

Ken,
I am interested in seeing how your scheme works and I don't think that the reeds will overheat but could they possibly hit the piston at certain revs?

Head mounted intake reeds have been used in millions of reciprocating compressors for over a hundred years.
As they are the major component affecting the units performance, efficiency & reliability, quite a bit of serious scientific study has been done on their dynamics.

Under normal circumstances the intake reeds must close when the pressure above the (rising) piston exceeds the static & dynamic pressure of the transfer flow.

If the engine speed was to exceed the design range by Very significant amounts, harmonics could mess up their behavior a bit.

346686

The above illustration does not include the damping effect of the sealing face or any travel limiter, if used.

Cheers, Daryl.

Frits Overmars

7th August 2020, 16:35

You refer to this employee a century ago in Goliath CP 700 engine which is from Bosch.
In exchange I mean this Spanish (I know you understand Spanish, but I don't know if you know how to read it, that's why I will try to translate it "googletraslate" .
The system is made up of three parts: two pumps, one of membranes (with carbon fiber sheets) and another line, and an injector.
The first is located behind the rear transfer of the cylinder and through a hole made in it sucks the gasoline from the tank taking advantage of the upward stroke of the piston. When it goes down, it creates a compression in the crankcase, from which a fitting emerges that drives the piston pump, located after the first pump and sends the mixture to the injector. This, coming from a kart carburettor with a carbon fiber guillotine, thus receives an injection of constant fuel, self-regulated by the engine rotation speed.
The whole secret of the operation of such a simple and ingenious system lies in the adequate calculation of the surfaces and diameters of the two pumps, to take advantage of the internal pressure and depression effects of the two-stroke engine.Thanks for the translation Ceci. I understand spoken and written Spanish (and Italian, French, English, German and even some Dutch) but not everyone will, so translations are always welcome. Of course we have Google Translator, but its capacities are limited; it still thinks a stroke is a medical condition.
The Martin Clerch system of using the crankcase pressure fluctuation reminds me of a Tillotson pumper carb. I cannot see a real difference. Am I missing something?

WilDun

7th August 2020, 19:04

Please enjoy my more than twenty year old proposal for the ultimate ligthweight two stroke genset.

https://archive.vn/s7gTY/49bac5b7a1bbba2a56273fb368fa9509943819dd.jpg

Two wheel drive with an electric motor in front and rearwheel is within reach.

Neils,
Glad to see you have been toying with this idea for so long!
Next we have to convince people that the present two stroke design will not be able to cope with what is expected of it (by the powers that be) as the bar continues to rise!
But will any manufacturer want to take the risk? (they have more or less given up except in the area of simple scooters or in certain sporting areas such as Snowmobiles or Karting!).
Will a driven front wheel ever be necessary?

ceci

8th August 2020, 04:49

The Martin Clerch system of using the crankcase pressure fluctuation reminds me of a Tillotson pumper carb. I cannot see a real difference. Am I missing something?

The three indicated systems (Martin Clerch, Stihl and Bosch) are not valid to be used in TPI ?.

The fluctuation in crankcase pressure may not be sufficient to pump at the proper pressure for the present-day injection (Spray creation), which implies that a suitable injector must be developed for this system.

The pumping pressure can also be increased, interacting with effects that occur in other parts of the 2S process.

Flettner

8th August 2020, 16:17

Progress, but slow.
It will fit but it will be tight.
Building the top crankcase pattern next.

ceci, this one could run carburetors, rival DI?

breezy

10th August 2020, 05:09

ceci

10th August 2020, 19:46

ceci, this one could run carburetors, rival DI?

If the OP system can be the future of 2S

ken seeber

10th August 2020, 23:23

Possibly not directly related to this thread, but something about some more bits for the cause.

In this case, the next version of the UHV, which will feature an assymetric layout, this needed new head and reeds. So, you can see the unfinished head (no combustion bowl as yet), the reed valve to suit and the "waste" piece which is a leftover from the wire cutting process. The very thin arms are only 0.5 radially wide.

346730

Frits Overmars

11th August 2020, 00:10

Ken, if you ever need a UHV logo:
346732 346731
(maybe a bit prickly)

Flettner

11th August 2020, 09:01

Niel, any chance of a simple pencil drawing of the cylinder piston crank set up you have in mind..im thinking of alternatives to bolting to an existing engine with your casting expertise.. and room for the set up....are there pulley wheels and belts involved for the drive off the crank/cranks?

Do you want last weeks layout, or next weeks layout?
Surprisingly the design is still in a state of revision, even at this late stage. Ill draw up a general layout if you like and post it.

Flettner

11th August 2020, 09:10

If the OP system can be the future of 2S

Perhaps,
But Im going to have a go anyway and have a bit of fun trail riding it, if it runs well enough. I am confident I will get some track time.

ken seeber

11th August 2020, 12:09

Ken, if you ever need a UHV logo:

(maybe a bit prickly)

Hahaha Frits, you're right. I often think it is a prick of a thing and what am I doing...:facepalm::facepalm:

WilDun

11th August 2020, 15:17

Hahaha Frits, you're right. I often think it is a prick of a thing and what am I doing...:facepalm::facepalm:

Just keep plugging on ......... Proof of the pudding is in the eating!

ken seeber

11th August 2020, 17:06

husaberg

11th August 2020, 19:09

ceci

11th August 2020, 23:25

A compression ratio question. For my initial phase UHV project where:
-106 cc aircooled
-test rpm of around 3800 rpm
-power level around 2 hp (low I know, but gotta start somewhere and if it 2 strokes at light load then that is a good thing)

Hi Ken
His work together with that of Katinas, are very useful if you want to make a pump driven by crankcase fluctuation.
Thank you

Frits Overmars

12th August 2020, 23:42

A compression ratio question. For my initial phase UHV project where:
-106 cc aircooled
-test rpm of around 3800 rpm
-power level around 2 hp (low I know, but gotta start somewhere and if it 2 strokes at light load then that is a good thing)
Just wonder what CR I should be looking at. Have been using 15:1 (total), but thought it may be wise to get some opinions.Two-stroking at light load is a good thing indeed. The two-stroking means no unburned HC emission due to misfiring caused by insufficient mixture quantity, purity or igniteability, and the light load means no NOx-production and low thermal stresses for the engine. In the case of Ken's UHV it specifically means low thermal and pressure stresses for the reeds.

A low compression ratio would contribute to reducing these stresses, but it would also reduce the engine's thermal efficiency. Its specific fuel consumption would go up and the environment would suffer (I remember the times when we did't yet have an environment and petrol cost 40 cents a liter. Those were the days).

As in any engine, combustion should be rapid, which requires squish and a compact combustion chamber. Or Homogeneous Charge Compression Ignition, but HCCI requires a high BMEP, which could be detrimental to the reeds, so unfortunately I cannot see a combination of UHV and HCCI.

Squish then. The present UHV layout seems to permit a fairly tight squish gap; the reeds only need room to move when the piston is away from TDC. And anyway, if the reeds were closing too slowly, the piston would help them, like it would 'help' the exhausts valves in a four-stroke.

The reed layout that Ken showed us the other day, might produce something other than squish, namely tumble. In a four-stroke, tumble is a welcome substitute for squish. But for a two-stroke I'm not so sure, because tumble will give a thorough mixing of fresh charge and exhaust gases. Four-strokes nowadays thrive on Exhaust Gas Recycling. In a two-stroke it would rather be Exhaust Gas Retention and I've always tried to avoid that. But then I've always tried to find power, while Ken's goal is to save the environment. Maybe it's time to reconsider my goals.

WilDun

13th August 2020, 11:28

Two-stroking at light load is a good thing indeed. The two-stroking means no unburned HC emission due to misfiring caused by insufficient mixture quantity, purity or igniteability, and the light load means no NOx-production and low thermal stresses for the engine. ................................................. But then I've always tried to find power, while Ken's goal is to save the environment. Maybe it's time to reconsider my goals.

FRITS
Although I have not mentioned the word "tumble" ( only found it when I started delving into what other people were thinking and found that was what it was being called!), so now I realize I have been an advocate for "tumble" for quite some time -maybe a couple of years, to be more precise!.

However, you are discussing it in terms of the "normal" two stroke operation ( Schnurle transfer, tuned exhaust, expansion chamber, squish etc etc) where I feel it will only introduce more problems. - but contrary to your view as encouraging mixing of fresh and used gases. In the OP engine layout I see it also as a means of peventing mixing, by forming a slower self contained moving plug - could that be considered a possibility??

So for quite a while I have been proposing OP type despite its PAL (potentially awkward layout) but suitable for using HCCI, combined with my own ideas on how to introduce a "tumble" type fresh charge to the cylinder, also variable compression for startup, no more crankcase pumping (to give it the chance of proper lubrication), using a turbocharger etc. - this whole layout being (to my mind) much more useful than the "mixing pot" that the common (successful till now) Schnurle system tends to produce by swirling at high speed through the used charge still in the cylinder! - some people may make claims to the contrary!

Not at all meaning to decry other peoples' ideas and efforts of course - all ideas valid for rearranging the two stroke for its survival do need to be considered!

My big problem of course is that relatively speaking, I am a layman here (and not trying to compete with anyone) - I realize that most of you guys could shoot me down in flames if you felt like it! - (if you do feel that way, do so - then I'll have learnt a bit more!) ............ I'm willing to take that risk, but it sometimes feels like.....:brick: and then sometimes, am I right or wrong? ..... :shit:

ken seeber

13th August 2020, 14:10

Two-stroking at light load is a good thing indeed. The two-stroking means no unburned HC emission due to misfiring caused by insufficient mixture quantity, purity or igniteability, and the light load means no NOx-production and low thermal stresses for the engine. In the case of Ken's UHV it specifically means low thermal and pressure stresses for the reeds.

A low compression ratio would contribute to reducing these stresses, but it would also reduce the engine's thermal efficiency. Its specific fuel consumption would go up and the environment would suffer (I remember the times when we did't yet have an environment and petrol cost 40 cents a liter. Those were the days).

As in any engine, combustion should be rapid, which requires squish and a compact combustion chamber. Or Homogeneous Charge Compression Ignition, but HCCI requires a high BMEP, which could be detrimental to the reeds, so unfortunately I cannot see a combination of UHV and HCCI.

Squish then. The present UHV layout seems to permit a fairly tight squish gap; the reeds only need room to move when the piston is away from TDC. And anyway, if the reeds were closing too slowly, the piston would help them, like it would 'help' the exhausts valves in a four-stroke.

The reed layout that Ken showed us the other day, might produce something other than squish, namely tumble. In a four-stroke, tumble is a welcome substitute for squish. But for a two-stroke I'm not so sure, because tumble will give a thorough mixing of fresh charge and exhaust gases. Four-strokes nowadays thrive on Exhaust Gas Recycling. In a two-stroke it would rather be Exhaust Gas Retention and I've always tried to avoid that. But then I've always tried to find power, while Ken's goal is to save the environment. Maybe it's time to reconsider my goals.

Good stuff Frits,

Yes, there is a bit of a dichotomy between power and emissions. Interestingly, in some situations, the improvements of one can benefit the other.

At the end of the day, one just doesn’t want to lose any unburnt fuel out the exhaust, unless for some obscure reason like post combustion heating up of the exhaust for tuning or catalyst reasons.

Not sure at all what pressure the reeds will take under running conditions, but time will tell. It will also tell of the “asymmetric “ layout (the cactus) that I am currently preparing will also be of any benefit. When completed, I intend to do a proper back to back shootout, on same day, of all the combinations and lay bare the results.

One possibly secondary benefit of the UHV is that it will allow additional cylinder charging after exhaust port closure, say using a blower or turbo.

Vannik

13th August 2020, 18:55

FRITS
Although I have not mentioned the word "tumble" ( only found it when I started delving into what other people were thinking and found that was what it was being called!), so now I realize I have been an advocate for "tumble" for quite some time -maybe a couple of years, to be more precise!.

However, you are discussing it in terms of the "normal" two stroke operation ( Schneurle transfer, tuned exhaust, expansion chamber, squish etc etc) where I feel it will only introduce more problems. - but contrary to your view as encouraging mixing of fresh and used gases, in the OP engine layout I see it also as a means of peventing mixing, by forming a slower self contained moving plug - could that be considered a possibility??

Two things:
1. A loop scavenged engine is using tumble - the loop flow by its very nature is the tumble motion, the trick is to control the tumbling speed.
2. OP engine has a serious issue with scavenging, you pretty much have to choose between swirling flow and plug flow or come up with something new.

Swirling flow by its centrifugal motion displaces the fresh charge to the outside and can create a down flowing central column of burn gas, leading to low scavenging efficiencies. There are a large number of publications available on this topic.

Plug flow in an OP engine seems to be a neglected topic.

Frits Overmars

13th August 2020, 20:48

Flettner

13th August 2020, 21:13

Thank you Neels. I was contemplating a response to WilDun's remarks, but you said it all. I would try to avoid swirl in any engine that has circumferential exhaust ports.
I think swirl only makes sense in engines like the giant marine diesels with overhead exhaust valves that offer a way out for the trapped central column of burnt gas.

I try to approach plug flow in our conventional two-strokes and I use proper plug flow in my symmetric scavenging FOS system. By the way, Neil Hintz has cylinders with this same scavenging suystem layout about :D.

And I have a new cylinder with a new layout.

I'm desperately trying to find time finish and test this new concept, but work keeps getting in the way bugger it. We might be in for another Covid lock down here in NZ shortly,
What Im really missing is a heat treating oven, then Im largely self sufficient, trade me time.

Frits Overmars

13th August 2020, 21:28

I would try to avoid swirl in any engine that has circumferential exhaust ports. I think swirl only makes sense in engines like the giant marine diesels with overhead exhaust valves that offer a way out for the trapped central column of burnt gas.Come to think of it, with scavenging ports at one end of a cylinder and circumferential exhaust ports far, far away at the other end, swirl might not be quite so bad. Still, I think I'd prefer plug scavenging.

WilDun

13th August 2020, 23:55

I'll have to sit down and digest all that properly! - well, after all, I did ask for it really! - now you guys have gone and upset my rythm! :facepalm:

Frits, on your FOS cylinder - could it be that the (normal) curvature of the transfer ports creates something akin to "swirl" like situation, causing the oil, petrol and air to separate in the passage with the oil and petrol being introduced perilously close to the outgoing exhaust gases? - the oil then becoming (as it were ) the "boundary layer" between the fresh and spent gases moving in opposite directions?

Anyway, as I said I guess I'll have to sit down and ponder everything in the last few posts a bit more! - but tomorrow - it's bedtime here!

BTW. we are in stage 3 lockdown in Auckland ..... again!

Frits Overmars

14th August 2020, 01:21

Frits, on your FOS cylinder - could it be that the (normal) curvature of the transfer ports creates something akin to "swirl" like situation, causing the oil, petrol and air to separate in the passage with the oil and petrol being introduced perilously close to the outgoing exhaust gases? - the oil then becoming (as it were ) the "boundary layer" between the fresh and spent gases moving in opposite directions?For clarity: swirl is a gas rotation around the longitudinal cylinder bore axis. Generating swirl would require tangentially-aimed ports, but I took great care in aiming all six of my transfer ducts radially, so I don't think there is any swirl in the FOS cylinder; at least I hope not.

Because of the curvature of just about every transfer duct there will be a tendency to fling the heavy petrol and oil droplets to the duct's outer walls. Lubricating the opposite gas movements in the boundary layer is an amusing thought, I must say Will. It's one of those things that I hadn't thought of until you pointed me at it :D.

OopsClunkThud

14th August 2020, 06:31

If the OP has a smaller exhaust piston then the swirl would be contained somewhat from flowing out of the radial exhaust.

Flettner

14th August 2020, 07:25

If the OP has a smaller exhaust piston then the swirl would be contained somewhat from flowing out of the radial exhaust.

My boat uniflow engine utilized differential size pistons, exhaust smaller. 50 against 56, so made for a small squish area, also makes the combustion chamber a less awkward shape. This engine would run to 9500 rpm under load, non tuned pipe.
It has six transfers, two from one crankcase creating a small amount of swirl with the other four creating a central plume. Interestingly the central plume fuel was overly rich, 66%, outside swirl at 33%. This was to help fuel cool the exhaust pistons.
This was all done 25 years ago.

OopsClunkThud

14th August 2020, 09:00

This was all done 25 years ago.

and still seems highly relevant

WilDun

14th August 2020, 09:21

For clarity: swirl is a gas rotation around the longitudinal cylinder bore axis. Generating swirl would require tangentially-aimed ports, but I took great care in aiming all six of my transfer ducts radially, so I don't think there is any swirl in the FOS cylinder; at least I hope not.

Because of the curvature of just about every transfer duct there will be a tendency to fling the heavy petrol and oil droplets to the duct's outer walls. Lubricating the opposite gas movements in the boundary layer is an amusing thought, I must say Will. It's one of those things that I hadn't thought of until you pointed me at it :D.

Frits,
I find it difficult to get my message across in 'written only' conversations and so I tend to use 1000 words to describe even the simplest thing properly! so forgive me !

I guess you answered the question in the second part also, - I wasn't actually trying to describe swirl in the cylinder.
What I was meaning really was the 'centrifuge effect' (not swirl) caused by the curvature of the ports just before it enters the cylinder- obviously you get that in any curved duct (depending on the speed of the flow), but due to the fact that in your FOS system the opposing flows of the 'in and out' gasses would actually come in contact and the transfer flow (now in a in a vulnerable "stratified" ?? form) would be a sitting duck for being dragged into the exhaust especially the outer layers consisting of oil and petrol.

Regarding the situation in the cylinder ie in a normal Schnurle type engine, whatever flow type (either swirl or tumble) is being employed, it surely must be a confused and cramped situation! and there can be no escaping the fact that the two charges will mix!

Whereas in the OP engine, there is room for separation of the charges and even a puff of air in between them. as Neil suggested a long time ago!

So, in the case of OP, (using 'tumble flow') - Is there the possibility of a slower moving 'slug' of mixture, maintaining its integrity as it moves down the cylinder to push out the remaining exhaust gas without actually mixing with it?

And yes, my "statements/questions" could be seen as amusing of course (and I don't mind that at all) - but question is, can you see any validity in them? :laugh:

Flettner

14th August 2020, 09:41

Probably combustion chamber shape and exhaust piston thermal control are the worst features of the OP uniflow.
Differential piston size, exhaust being smaller and with a flat top, means a reduction in surface area to absorb heat but ultimately a different piston makeup / design is needed also.In my single cylinder OP Im running E85, total fuel supply through the exhaust crankcase for best piston cooling I can get. Other end is just air at higher loads. Low load running fuel will be only from the cold end via TPI. So a a lot going on, computer will be busy.

In saying this my new engine has same size pistons, partly to do with the fact that if its cast as one continuous bore size its seen as a single cylinder as far as plating cost goes, as good a reason as any.

WilDun

14th August 2020, 11:10

Probably combustion chamber shape and exhaust piston thermal control are the worst features of the OP uniflow.

Have you abandoned the thought of using HCCI? - I had thought that it might've been a good way around poor CC shape! also I thought that overall combustion temperature would be lower (my understanding). - I guess HCCI is't completely developed as yet!?

Differential piston size, exhaust being smaller and with a flat top, means a reduction in surface area to absorb heat but ultimately a different piston makeup / design is needed also.In my single cylinder OP ..............

Not all that clear on the significance of the use of squish or not using squish - how does it affect keeping it 'clean' ?- opinion seems a bit varied on this!- could HCCI totally bypass this dilemma?

In saying this my new engine has same size pistons, partly to do with the fact that if its cast as one continuous bore size its seen as a single cylinder as far as plating cost goes, as good a reason as any.

Good reason! but will the combustion chamber shape be a big handicap (in your design?) I realize that the more over square the bore/stroke ratio, the worse the CC shape will become!

Having said all that, just have a look at a high performance four stroke engine - could the combustion area on that be called a good shape?

Flettner

14th August 2020, 15:08

Got to start somewhere, spark ignition initially. Three plugs too, or was it two and one glow plug, or one and two glowplugs. Or three compression intensifiers, or a radio active isotope that pops into combustion chamber at just the right time, or .... there are many possibilities, some more real than others.

All kidding aside, my first OP 100cc started out with just a single plug per cylinder. About 40 degrees advance to get it to run anywhere near normal. I fitted two model airplane glow plugs opposite the spark plugs in the combustion plate. Instant retard to 20 drgrees. So thats when I sat down and jolly well learnt to build my own DC CDI's, what I wanted was not available, in NZ and if it was I couldn't afford it anyway. Also intetesting to see the light carbon build up on this combustion plate down wind of the direction of swirl from the sparkplug. This engine just had six ports creating a swirl pattern. Pistons were same size with domes, so combustion chamber shape was ugly. Zenoa weed eater pistons.

WilDun

14th August 2020, 15:38

Got to start somewhere, spark ignition initially. ............This engine just had six ports creating a swirl pattern. Pistons were same size with domes, so combustion chamber shape was ugly. Zenoa weed eater pistons.

Just the same there was a lot of stuff you learnt from that experiment which you will know to avoid this time!

Yes there are a lot of different scenarios to investigate which points to the possibility of eventually finding some interesting innovation for the future.

That is more than you could do with present day layouts - in my opinion, only cosmetic and tiny changes possible anymore (ie after TPI of course!)
Although perhaps Ken's idea will prove me wrong! - but whatever, I think something drastic needs to be done!

Flettner

14th August 2020, 16:17

Probably the wrong place for this but,
Building the top crankcase pattern, shes got that lovely black number on again. Somehow have to fit a rotary disc valve housing to this. 3D modeling on the fly.

ceci

15th August 2020, 19:50

25 years ago they already worked on the same approach as me

Flettner

15th August 2020, 20:35

https://youtu.be/lHWsjeCznm0

Motobacane, 1974, electronic fuel injection. Injecting into the boost port.

ceci

16th August 2020, 02:55

I do not think that any type of injection will be superior to the electronic one, but for what reason there cannot be one less effective, but also more economical.
The whole world is not just Europe. North America or Australia

Flettner

16th August 2020, 08:52

Or New Zealand.

I still find it hard to believe mechanical can be cheaper. If you go to any car wreakers yard in the world you will find all the nessasery componentry to build your own TPI.
You might need to be a bit of an electronic wizard to make a car ecu do what you want but the hardware is already in there. Stuff sooo cheap its just being sent off for recycling or just trampled into the mud.

WilDun

16th August 2020, 11:29

The 'whole world' (as far as everyday common commuter motorcycles are concerned) is mainly SE Asia and India etc and the profits will come from there as well - these guys will still manage to adapt things to suit themselves for any purpose,whatever they are dished up though!!!

The two stroke still has a chance, but it needs to hurry, because time is fast running out so it'll have to be cheap to beat the dreaded four stroke and so needs to remain simple (and the two stroke still has the edge on simplicity, but not in clean running) - and yes, there is (surplus, well proven) electronic technology, turbos etc. around these days so we need to make use of it all, instead of trying to re-invent the old mechanically simple stuff!

190mech

16th August 2020, 12:13

I read an article in 'Motocross Action' some years back that stated EFI(4stroke) was cheaper to build than a carbed bike ,,as carbs have many small passages and precise dimensions,an EFI setup has an in tank pump/regulator,throttle body,injector,and program box..I know from reading here a piped racing 2stroke engine is hard to EFI,but there are quite a few examples of lower revving engines that work well with a simple EFI system..

ceci

16th August 2020, 20:57

https://youtu.be/lHWsjeCznm0

Motobacane, 1974, electronic fuel injection. Injecting into the boost port.

Sorry to forget about New Zealand, if I have bothered someone excuse me.

Motobecane OK, the patent for this system expired on 1992-05-06,
https://patents.google.com/patent/US3881454A/en?inventor=Eric+Jaulmes
because being free the technology was not used by other brands? using these the EV-6 injectors

Why is it that the TPI is more successful than Motobecane ?: the use of the EV-14 injector, since with the EV-1 it would not work.
The success of the TPI is in the way of using the injectors and not in what type of injector is

https://patentimages.storage.googleapis.com/cd/da/e4/d6a34f05c79fb3/US3881454-drawings-page-2.png

ceci

17th August 2020, 23:33

It must be recognized that regardless of functionality, the issue of electronics on the motorcycle is something very beautiful, from the times when the Game Boy was used until today when smartphones are used.
In addition to what I already mentioned with the topic GPS smart injection
https://pbs.twimg.com/media/ED0PvTCWwAU98yf?format=jpg&name=small

https://centromotopalma.es/storage/app/uploads/public/5ca/4b0/8d3/thumb_1323_750_500_0_0_crop.jpg

WilDun

18th August 2020, 09:45

Why has HAUFEN started this thread and never been heard from since - is he no longer with us? ........... I have asked this twice before and there has been no reply - so third time lucky?

Vannik

18th August 2020, 18:12

Why has HAUFEN started this thread and never been heard from since - is he no longer with us? ........... I have asked this twice before and there has been no reply - so third time lucky?

Maybe on summer holiday - he is from that part of the globe.

husaberg

18th August 2020, 19:25

https://www.researchgate.net/publication/278345605_Exhaust_gas_emissions_of_small_capacity_ 2_4_stroke_engines

WilDun

18th August 2020, 20:04

https://www.researchgate.net/publication/278345605_Exhaust_gas_emissions_of_small_capacity_ 2_4_stroke_engines

A lot of interesting stuff there!

mr bucketracer

19th August 2020, 21:17

Will the 2 stroke engine do the same k's as a four stroke before rebuilds?

WilDun

20th August 2020, 08:57

Will the 2 stroke engine do the same k's as a four stroke before rebuilds?

No, it won't if it doesn't make a comeback on the roads! ........
To have any chance of ever coming back, first we have to accept the fact that it has already gone!

It will need proper (positive) lubrication, not mixing oil with petrol, smaller individual ports, instead of great gaping (racing style) holes in the cylinder wall, (think of the rings) and instead of reaching for the sky in peak horsepower we need to focus on a clean exhaust (totally necessary today - no longer any room for debate there), also maybe a need for the great fuel injection debate to be resolved, it will need to be a very different two stroke!

Also we have to think of the Bucket Racer boys, stuck with the prospect of no more road bikes to modify anymore! (the only alternative being the four stroke!) :laugh:

That's what I believe anyway - we can't bury our heads in the sand any longer!

ken seeber

20th August 2020, 13:39

No, it won't if it doesn't make a comeback on the roads! ........
To have any chance of ever coming back, first we have to accept the fact that it has already gone!

It will need proper (positive) lubrication, not mixing oil with petrol, smaller individual ports, instead of great gaping (racing style) holes in the cylinder wall, (think of the rings) and instead of reaching for the sky in peak horsepower we need to focus on a clean exhaust (totally necessary today - no longer any room for debate there), also maybe a need for the great fuel injection debate to be resolved, it will need to be a very different two stroke!

Also we have to think of the Bucket Racer boys, stuck with the prospect of no more road bikes to modify anymore! (the only alternative being the four stroke!) :laugh:

That's what I believe anyway - we can't bury our heads in the sand any longer!

I think you're right, but maybe there are other application opportunities where it might see a return.

Basically agree, with maybe longer skirt pistons. Now here is a question: Back in their day, what was the life of Trabants, DKWs, SAAABs, BSA Bantams etc? When I was a post pimple kid when we had bikes, Jawas, Bultacos, T20 Suzukis, etc I just don't remember anyone really boring out cylinder etc to replace pistons, maybe cos we were too broke to afford them.

Have made the suggestion here before, recognising this is a looming issue, that maybe they could consider the use of 125 cc TAG style kart engines. They are clutched, water cooled, durable, around 28 hp, relatively cheap and available. Would require a mounting system and a jackshaft in the drive train, but provided endless possibilities for class structures; eg standard, modified, really modified, CVT, etc etc.

WilDun

20th August 2020, 15:09

I think you're right, but maybe there are other application opportunities where it might see a return.

Basically agree, with maybe longer skirt pistons. Now here is a question: Back in their day, what was the life of Trabants, DKWs, SAAABs, BSA Bantams etc? When I was a post pimple kid when we had bikes, Jawas, Bultacos, T20 Suzukis, etc I just don't remember anyone really boring out cylinder etc to replace pistons, maybe cos we were too broke to afford them.

KEN,
That was way before they invented the environment and we accepted all the failings of the ones you mention (cos we didn't know any better!) and no, they never did the mileages you would have expected of a car (in those days a car engine wouldn't last nearly as long as today either!) but we just accepted that - we believed in them and only wanted to modify them (including the Bantam and the T20 in my case).

Now, all that carefree attitude has come to haunt us! and we need to admit that the present day two stroke has had its chips as far as being a common sight on the roads is concerned! and even with a completely redesigned two stroke we would still have to face an uphill battle to ever get it back!

I have often talked about this (and I need to admit that unlike you, that's mainly all I do these days :laugh:), and have wondered what else it can be used for - but same old answer, it's mainly only for use in poxy little scooters, (a lot of guys get a lot of pleasure out of modifying these too!) garden tools etc. however, more sophisticated two stroke engines are used in snowmobiles and light aircraft. - and of course, motocross/enduro! (sometimes).
Karting, above all, does most to keep it on the planet of course!

Have made the suggestion here before, recognising this is a looming issue, that maybe they could consider the use of 125 cc TAG style kart engines. They are clutched, water cooled, durable, around 28 hp, relatively cheap and available. Would require a mounting system and a jackshaft in the drive train, but provided endless possibilities for class structures; eg standard, modified, really modified, CVT, etc etc.

Not sure if you're referring to Bucket Racing here (guess you are) - but that does sound like a good idea in the meantime anyway! - not really suitable for everyday road motorcycles of course!....... keep plugging on with your latest idea and climb another step up and try to rescue this thing! :niceone:

mr bucketracer

20th August 2020, 18:32

This guy is on it at 16.30 https://youtu.be/3eozooUOhco

Flettner

20th August 2020, 19:36

This guy is on it at 16.30 https://youtu.be/3eozooUOhco

Whats your point?

mr bucketracer

20th August 2020, 19:58

Whats your point?the point been . Hes on it ?predicted the future? What more do i say lol. Up to you to guys change it I guess

WilDun

20th August 2020, 20:24

This guy is on it at 16.30 https://youtu.be/3eozooUOhco

I think that guy was actually looking back though!

All very depressing stuff of course - and I know that many believe that "Elvis aint dead" but he is! - also Greg Hansford ..... and Pat Hennen only just escaped death in the IOM TT!

I guess we will all be the same to a certain extent, but maybe just thinking and acknowledging, rather than denying the truth, accepting it how it really is and trying to do something about it will bring some happiness back - it is possible but things WILL need to change somewhat - trying to stay rooted in the past and becoming bitter is what kills old men (like me!).

Taking on change is the most difficult thing we have to do!

mr bucketracer

20th August 2020, 20:36

All very depressing stuff of course - and I know that many believe that "Elvis aint dead" but he is! - also Greg Hansford ..... and Pat Hennen only just escaped death in the IOM TT!

I guess we will all be the same to a certain extent, but maybe just thinking and acknowledging, rather than denying the truth, accepting it how it really is and trying to do something about it will bring some happiness back - it is possible but things WILL need to change somewhat - trying to stay rooted in the past and becoming bitter is what kills old men (like me!).

Taking on change is the most difficult thing we have to do!yes . I love all engines 4 2 stroke or wankels. And of course anything made out the ordernealy. I'm a engineer that's it . Love it . Hate me if you like. Good video wildun ah ?

husaberg

20th August 2020, 20:36

the point been . Hes on it ?predicted the future? What more do i say lol. Up to you to guys change it I guess

It looks like Kel Curuthers who went on for another 20 years with two strokes after that.......he retired from 2 strokes in 1998.
when i was growing up two strokes had forced out the 4 strokes from MX it took a rule change givin 4t a 100% advantage to change it
The 2t's running cost per hour is a tiny percentage of a competition 4t for MX or MotoGP.
Funny enough his world tittle while riding was on a 250 4 cylinder 4t Benelli after all the other works teams pulled out a season early due to the change in the rules limiting the cylinders for the next season.

mr bucketracer

20th August 2020, 20:46

It looks like Kel Curuthers who went on for another 20 years with two strokes after that.......he retired from 2 strokes in 1998.
when i was growing up two strokes had forced out the 4 strokes from MX it took a rule change givin 4t a 100% advantage to change it
The 2t's running cost per hour is a tiny percentage of a competition 4t for MX or MotoGP.
Funny enough his world tittle while riding was on a 250 4 cylinder 4t Benelli after all the other works teams pulled out a season early due to the change in the rules limiting the cylinders for the next season.it is like that's lots of guys would rather got 2 stroke for mx I know . For me i can can pull i top of a 4 stroke and put back on pretty dam fast . So dont bother me . Have you got a link to the 2 stroke with the guide to piston that runs like a banana. Stops a lot on piston wear. New Zealand built?

Flettner

20th August 2020, 21:05

it is like that's lots of guys would rather got 2 stroke for mx I know . For me i can can pull i top of a 4 stroke and put back on pretty dam fast . So dont bother me . Have you got a link to the 2 stroke with the guide to piston that runs like a banana. Stops a lot on piston wear. New Zealand built?

You got something to offer, here?

mr bucketracer

20th August 2020, 21:19

You got something to offer, here?have you ? I have ideas but because I don't like been knocked down. I dont offer I just get on with it.

husaberg

20th August 2020, 22:25

Condyn

20th August 2020, 22:53

The technology is already out there. Find a way around the patents and two strokes shall live on.

ken seeber

21st August 2020, 00:13

The technology is already out there. Find a way around the patents and two strokes shall live on.

Condyn,

The ETEC technology is successful, well known and is evolving it seems, but the big test is whether BRP pursue it to an automotive / motorcycle application. ETEC, a derivative of the Ficht that sent OMC broke, has been around for many years, possibly enough for many key patent claims to be now expired.

Love to see any additional clean ideas here though.

Unburnt fuel being the #1 objective.

WilDun

21st August 2020, 01:37

yes . I love all engines 4 2 stroke or wankels. And of course anything made out the ordernealy. I'm a engineer that's it . Love it . Hate me if you like. Good video wildun ah ?

All the same applies to me except that I'm an ex "hands on engineer" more commonly known as "armchair engineer"- retired a long time ago - maybe even a 'wanker' too, like yourself!). ..... well, you said it! :laugh:.

Liked the video, took me right back to all the smoke and rattles on the overrun etc. That guy was probably right of course at the time he put the video online but we don't have to listen to his miserable predictions!

I like all engines as well, but I was always very keen on two strokes, ie when I found that they were used on bikes (as well as model aircraft)!.
Still, the beautiful smell of Castrol R was was engraved on my brain from the very early sixties (from the days of Manx Nortons, Goldies, 7R etc.) - pity it used to gum up the rings on my T20 so I had to change!

Always been a two stroke fan of course and I don't think we should give up on it just yet, it's still got potential - but it's got to change big time and also needs sales in order to make a comeback, and those sales will come from all the millions of commuters in third world countries.

We need to change it to be less race orientated,- a little more subdued, flexible, clean running and economical machine to suit that category.
When the market is filling up with that type of bike, then racing will again grow out of that! - and you can guarantee there will be a lot of guys wanting to modify and improve them (so Bucket Racing will be saved).

These classes may not have the traditional type transmission of course - but the guys who do scooter racing seem to be enjoying them just the same!

WilDun

21st August 2020, 01:52

The technology is already out there.

Find a way around the patents and two strokes shall live on.

That's probably more difficult than designing something revolutionary from scratch! - at least you could just go ahead and do that in your garage without employing a lawyer!

Condyn

21st August 2020, 03:26

If you have never been around an etec fueled engine, its something amazing. They take the “ purr like a kitten “ phrase to a new level. Modifying an existing engine however is a challenge. I plan on adding a turbocharger to my etec injected snowmobile and will have to add supplementary fuel injectors which will surely short circuit some, reducing the huge advantage of the direct injectors. BRP released a Factory turbocharged two stroke etec fueled snowmobile in 2019 being sold now. I really dont see a death to that market in the near future. There are a few manufacturers selling loads of two strokes that arent direct injection. The etec system really could be the future! Though it should be noted to never underestimate the power of greed

Its nice to see different ideas that are more practical for the masses. Personally I would rather ride a wet fart 4 stroke than have an exhaust valve on a 2 stroke. That takes the fun right out of it.

ceci

21st August 2020, 07:18

The ETEC technology is successful, well known and is evolving it seems, but the big test is whether BRP pursue it to an automotive / motorcycle application. ETEC, a derivative of the Ficht that sent OMC broke, has been around for many years, possibly enough for many key patent claims to be now expired.

Common rail is only equipped by Fiat cars, not of course they sold the patent to Bosch and now all car manufacturers use it.
DiTech the same as the common rail but scooter

Flettner

21st August 2020, 07:37

have you ? I have ideas but because I don't like been knocked down. I dont offer I just get on with it.

In fact I do, I believe I've contributed my fair share.
Contribute away.

WilDun

21st August 2020, 10:18

Flettner is correct in what he says .....
You could say he has cracked it, because I'm told that KTM have (unsuccessfully so far) tried to patent his injection system (if that's not proof of concept what is?).
Everyone in the sport here knows it works, - its in his (enduro) Kawasaki Bighorn ) and he has been using that for quite some time! - This machine also uses many other important and successful improvements and innovations that he has developed over the years!

Condyn
I know it's hard to change, this is seen as fun in your sport (and rightly so - it is fun) Etec sure seems to be one way to go and it is certainly a huge step forward, although at the moment it seems to be primarily used in competition and the never ending search for more BHP/litre!
I'm sure it could be adapted for use in a more humble two stroke (too expensive at the moment I'm sure).

Mr Bucketracer, ....... everyone who comes up with new ideas (or even working concepts) and tries to explain them to others will get knocked back!

Flettner just gets on with it and accepts the concept of a high failure rate in order to eliminate the stuff which won't work (tries every avenue)! :niceone:

Ken's quote at the end of all his posts, is very inspirational!

ken seeber

21st August 2020, 15:02

WilDun

21st August 2020, 15:19

I wasnt meaning speed just $$$$$

PIston like a banana no idea
this guy speed of cheese was doing pistons

Yep, that video was clever and interesting stuff of course, but I see it as last ditch efforts to keep a dying traditional design still in circulation (but does it really make sense?).

That cylinder looks like a kitchen grater, doing a good job on the piston and rings) - then, a (lightweight for sure) piston which doubles as a crosshead, rocks like hell and doesn't really cope well with side thrust it's being asked to take! - all lubricated by some oily petrol! - that's not progress, it's clutching at straws!

We need to move on and take a quantum leap and totally redesign things.

husaberg

21st August 2020, 17:36

Common rail is only equipped by Fiat cars, not of course they sold the patent to Bosch and now all car manufacturers use it.
DiTech the same as the common rail but scooter

Ceci,
I'm a little confused. DiTech is the application (by Aprilia for their 50 cc scooter) of Orbital's injection system. This is not common rail in that the fuel is not injected through an injector by a very high system pressure. In the Ditech, the fuel is injected and atomised by the use of air pressure supplied by a small compressor driven by a cam on a crank web. From memory it might have had a 6 mm stroke with a 25 bore.

Bosch had 2 stroke Direct injection in the 1950's on the Gutbrod Superior 600 and Goliath GP 700.
it was mechanical but
Alfa Romeo 6C had electronic fuel injection in 1940

https://autouniversum.wordpress.com/2010/09/25/the-advent-of-fuel-injection/

As was typical of Carl F. W. Borgward, he didn't stop there, but instead worked together with Bosch to make the very promising carburation system fit for series production. After three years of development work, BORGWARD's Goliath brand became the first automaker besides Gutbrod to present a vehicle with direct petrol injection. The automobile in question, a Goliath sports coupé, was unveiled at the IAA motor show in Frankfurt in April 1951. It was another technical milestone from BORGWARD. The new two-stroke engine consumed just 5.9 litres of fuel per 100 kilometres. Moreover, at 29 hp, its output was 10 per cent higher than its predecessor's. Specific fuel consumption declined from 330 grams per hp and hour to 225 grams. This decrease was actually slightly greater than the 30 per cent that the technicians had forecast.
https://www.prnewswire.com/news-releases/borgwards-petrol-saving-marvel-direct-petrol-injection-made-its-debut-in-1951-at-the-iaa-motor-show---in-the-sleek-goliath-sports-coupe-551317231.html

Mazada new HCI engine i think has some ideas that can be pilfered
https://www.youtube.com/watch?time_continue=4&v=9KhzMGbQXmY&feature=emb_logo

or this
https://www.sae.org/publications/technical-papers/content/2012-32-0119/

Multi-Layer Stratified (MuLS) Two-Stroke Engine 2012-32-0119
The mandatory emission regulations coupled with market demands have resulted in the development of innovative engine technologies at lower costs for consumer applications. For example, the low cost two-stroke engines for hand-held applications have evolved from high specific output, high emission designs to lower emission engine architectures that meet today's EPA and CARB emission standards. Emissions and fuel consumption have reduced significantly, particularly in non-catalyzed engines. This paper highlights the design features of a Multi-Layered Stratified (MuLS) engine that has demonstrated the ability to meet the current emission standards without the catalyst. The Multi-Layer scavenging system consists of stratified layers of pure air, lean air-fuel mixture, and rich air-fuel mixture that are inducted separately and delivered in sequence into the combustion chamber through ports for minimizing the scavenging loss of the unburned fuel. A 25.4cc production two-stroke engine was modified to demonstrate the proof of the concept.

tpi 2012
https://www.sae.org/publications/technical-papers/content/2012-32-0115/

ceci

21st August 2020, 20:02

Ceci,
I'm a little confused. DiTech is the application (by Aprilia for their 50 cc scooter) of Orbital's injection system. This is not common rail in that the fuel is not injected through an injector by a very high system pressure. In the Ditech, the fuel is injected and atomised by the use of air pressure supplied by a small compressor driven by a cam on a crank web. From memory it might have had a 6 mm stroke with a 25 bore.

I was referring to the fact that the common rail and the DiTech do not work the same, they are equal in success, because both systems prevailed in their sector over the rest.
the ETEC system (Ficht) assimilated it (in commercial success, and somewhat similar in mechanical design) to the Volkswagen diesel pump injector.
When a system is successful, it is easily extended since commercial agreements are reached that immediately make them sell.

Frits Overmars

21st August 2020, 20:41

I was referring to the fact that the common rail and the DiTech do not work the same, they are equal in success.I was under the impression that DiTech almost drove Aprilia into bankruptcy when they mass-marketed a version that was still underdeveloped.

husaberg

21st August 2020, 20:58

I was under the impression that DiTech almost drove Aprilia into bankruptcy when they mass-marketed a version that was still underdeveloped.

Sounds a lot like the story of the other Italian manufacturer that marketed a Di 2 stroke in the 1990's.
346846

eldog

21st August 2020, 21:42

Mr Bucketracer, ....... everyone who comes up with new ideas (or even working concepts) and tries to explain them to others will get knocked back, because there are a lot of (wooses?) in this world who will not venture past the textbook or rulebook, (timid people who would never ever venture outside the square in anything) but who are prepared to ridicule those with enough courage to try, - often without actually having anything to offer instead!

Every inventor worth his salt has had to test the boundaries (at least to some extent and within the boundaries of common sense of course) in order to become successful
The biggest barriers are ..... the usual opposition from those who will not change and ..... the fear of failure or ridicule. - When you get past those barriers and don't give a stuff if others criticise you or your (reasonably sensible) ideas, then you're on your way!

Flettner just gets on with it and accepts the concept of a high failure rate in order to eliminate the stuff which won't work (tries every avenue)! :niceone:

Ken's quote at the end of all his posts, is very inspirational!

this is all to familiar to me.

I have found over the years, no matter what or how you explain something, you cannot get through to those you are trying to communicate with. Often because they cannot believe what you propose will work. Then you get someone else or you do it, there will never be any recognition when it works.

great to see, different ideas and actual testing, being conducted here.

ceci

21st August 2020, 21:50

I was under the impression that DiTech almost drove Aprilia into bankruptcy when they mass-marketed a version that was still underdeveloped.

The DiTech has been used in four different engines: Peugeot (France), Gilera and Aprilia (Italy) and Suzuki (Japan), if that is not be successful, you will tell me.
Tell me what other system has been used in various brands of vehicles (apart from the creator)

breezy

22nd August 2020, 02:21

breezy

22nd August 2020, 08:21

346857.... whats required..

Norman

22nd August 2020, 09:13

346857.... whats required..

As a range extender for a serial hybrid, what about a "Ryger" type with two optimized rpms, just as an example, optimized at 5000 and 7500 rpms (could engine design and so on be adopted for lower rpm?) And, using FTPI and catalyst with HC trap before main catalyst up in temp. As it is FTPI and not DI we can rule out PM. Pros AND cons, challenges with such a solution? Think 20-40 kW is needed..I do however feel a little bad about neglecting PM that is a problem in urban areas..In the background we are of course awaiting Flettners work and findings with his OP engine which I think must develop in the way and time Flettner has resources and time to do all the work required. Other developments that are interesting is of course if BRP is trying to develop an engine with rotating exhaust valves as per their patent, and also results from the Strange Developments two stroke engine. Other projects going on?

Norman

22nd August 2020, 09:27

As a range extender for a serial hybrid, what about a "Ryger" type with two optimized rpms, just as an example, optimized at 5000 and 7500 rpms (could engine design and so on be adopted for lower rpm?) And, using FTPI and catalyst with HC trap before main catalyst up in temp. As it is FTPI and not DI we can rule out PM. Pros AND cons, challenges with such a solution? Think 20-40 kW is needed..I do however feel a little bad about neglecting PM that is a problem in urban areas..In the background we are of course awaiting Flettners work and findings with his OP engine which I think must develop in the way and time Flettner has resources and time to do all the work required. Other developments that are interesting is of course if BRP is trying to develop an engine with rotating exhaust valves as per their patent, and also results from the Strange Developments two stroke engine. Other projects going on?

Just wanted to add that one application for a range extender is BMW i3, and others..And yes, it mighy be a side track of what we usually like to discuss here..

husaberg

22nd August 2020, 10:01

husaberg,
, are the emissions in the 2 stroke engine always beyond the allowable current rules? does an engine ever comply within its usual rev range? any graphs or reliable figures available to show this visually?

The rules are ever changing but as far as i know most emission are accelerating and decelerating and off powerband.
This is a brief overview i think.
https://www.tandfonline.com/doi/full/10.1080/027868290910224

WilDun

22nd August 2020, 11:36

this is all to familiar to me.

I have found over the years, no matter what or how you explain something, you cannot get through to those you are trying to communicate with. Often because they cannot believe what you propose will work. Then you get someone else or you do it, there will never be any recognition when it works.

great to see, different ideas and actual testing, being conducted here.

Uderstand? - UDERSTAND?

Anyway, - fact is, most people don't care! ..... they do not give a stuff about engines, motorcycles or any dirty smelly common rubbish like that - when there are much more important things in life. (like being seen and being fashionable!)

So is it any wonder that in (our NZ) sports news we get all the glitz and glamour of F1 (with the race details and results somewhere in there as well) ..... the only time bikes ever get a mention in the sports news is when there is an almighty crash! - like last weekend in Austria.

No one gives a stuff, or knows the difference between a two stroke and a four stroke - so we, or our opinions are not really relevant to this world! - only relevant here!....... it's all about today's "sensational" world unfortunately!

HUSA,
Why bother with all these boring details? - when tomorrow it'll be different - they will just keep raising the bar! - as soon as they see us catching up, then up it will go again - We are dealing with unreasonable "people" here who do not understand us or care! - they are really just "computers" programmed to stay ahead - they are not people! ...... but they are our masters!

Here is a compelling reason why two strokes should not be abandoned, or have to shoulder so much responsiblity for air pollution on roads, streets and waterways! (as they are having to do at the moment!). - nor should motorcycles in general have to share the blame to the same extent as the bloody boneheaded morons doing burnouts in cars!

[ “The latest research is indicating that non-tailpipe PM emissions are now 55-60% of vehicle emissions and this proportion will continue to grow with electrification of the fleet,” said Professor Frank Kelly of King’s College London, chair of the UK government’s Committee on the Medical Effects of Air Pollutants.

The committee estimates that between 28,000 and 36,000 deaths are caused by air pollution each year in the UK. Strong correlations between air pollution and increased mortality mean that this figure can be given with some confidence, although the uncertainty is reflected in the range of values. ]

But here is the whole thing - sorry, I've gone and got myself into the details after all! :facepalm: :-
https://www.imeche.org/news/news-article/this-is-why-electric-cars-won't-stop-air-pollution

eldog

22nd August 2020, 15:01

Uderstand? - UDERSTAND?

you have been the only one who has READ it. :facepalm::yawn:

It also shows that the brain is quite adept at 'guessing' what it sees and creates shortcuts to get us through.

Great to see the effort being made to 2S evolution

WilDun

22nd August 2020, 16:06

you have been the only one who has READ it. :facepalm::yawn:

It also shows that the brain is quite adept at 'guessing' what it sees and creates shortcuts to get us through.

Great to see the effort being made to 2S evolution

Yes, ......All except mine!! :laugh:

Oh and "evolution" isn't enough ....... needs to be "revolution"!

husaberg

22nd August 2020, 16:35

HUSA,
Why bother with all these boring details? - when tomorrow it'll be different - they will just keep raising the bar! - as soon as they see us catching up, then up it will go again - We are dealing with unreasonable "people" here who do not understand us or care! - they are really just "computers" programmed to stay ahead - they are not people! ...... but they are our masters!

but i love details...........
i agree with the premise that the emoissions need to be sorted just not the targeting of the fun bikes and competition bikes where the polution caused is minimal.
Also some stufff like the remivalal of lead likely resulted in more noxious and harmfull pollution from the witches brews that followed it.

WilDun

22nd August 2020, 18:08

We don't need fine details here right now - that's for, lawyers, nit-pickers, bean counters etc - maybe even ESE guys! (and Husa!) - but really, any half baked clown (including me) can see that there needs to be radical change first!

Fact is,we overdid the BHP/Speed thing, so let's turn back, get the basic changes set in the ball park first - lets forget about high power and racing (just for a little while).

When we have achieved that, set those finicky detail guys loose to get everything just right and we might end up with something useable on our roads!

Remember the old steam guys (when they lost their pride and joy to diesels) - they died muttering "won't work if it aint driven by steam" ..... lets not go that way - lets just move on!

Frits Overmars

23rd August 2020, 04:51

Just wanted to add that one application for a range extender is BMW i3, and others.And others, indeed Norman.
346873 346871 346872
Seriously, I would buy an E-car today if I could have an 800 km range, and charging points without waiting lists everywhere.

WilDun

23rd August 2020, 09:54

And others, indeed Norman.
Seriously, I would buy an E-car today if I could have an 800 km range, and charging points without waiting lists everywhere.

Yes, times change.

Flettner

23rd August 2020, 11:42

husaberg

23rd August 2020, 12:04

2020
https://www.cycleworld.com/story/motorcycle-news/kawasaki-to-design-supercharged-two-stroke-hybrid/

https://www.sae.org/publications/technical-papers/content/260039/

it took me 1/2 to find this in Drapers book it was described as having a rotary valve in the transfer port
so as best as i can figure out it had a disc valve controlled inlet air only port situated where a transfer port would normally be.

ISSN: 0148-7191, e-ISSN: 2688-3627
DOI: https://doi.org/10.4271/260039
Published January 01, 1926 by SAE International in United States
Annotation ability available

Sector:Automotive
Event:Pre-1964 SAE Technical Papers
Language:English
Abstract
Development of the two-cycle high-speed supercharged engine used in the Duesenberg racing cars that competed in the 1926 500-mile Indianapolis race is described. Excessive trouble in starting the engine, which requires considerably higher supercharger pressure than does the four-cycle engine, inclined the designer and builder to abandon the idea of using this type of engine in the race. The supercharger gear-ratio was not laid out for the extreme speeds and, as the engine speed is directly proportional to the supercharger pressure, the pressure was too low to give the desired speed. The speed and efficiency of the engine were increased by increasing the width of the cylinder intake-ports, but the author believes a supercharger pressure of 15 lb. per sq. in. is necessary for good operation. Best results were obtained when the rotary valve opened the intake valve after the exhaust ports had been opened about 3/16 in. As the pressure of the supercharger increased, better results were secured by setting the rotary valve to open the intake ports still later.
Although a number of piston-rings broke and pulled pieces out of the pistons when the car was first run on the Indianapolis Speedway, the engine continued to run, and the author concludes that, even in its imperfect state, the engine is not so delicate as a four-cycle engine and will run better, even though many things may be wrong with it, than will a four-cycle engine with only minor things wrong. The timing was unexpectedly sensitive, resulting in “popping-back” when the intake valve was opened a little too soon and in insufficient mixture charge in the cylinder when the valve was opened a little too late. It is believed this trouble can be controlled by the pressure of the supercharger.
By admitting cooling water around the exhaust port and then circulating it around the spark-plugs, steam pockets were avoided, the engine ran cooler, and the spark-plugs were much cooler than in the four-cycle engine.
Discussion of the paper concerns the amount of engine power required to drive the supercharger, speed of the supercharger, number of piston-rings used on the pistons, the maximum engine-speed, the gear-ratio of the car, the cylinder compression-ratio, the engine idling-speed, the ignition firing order, spark-advance, type of spark-plug used, relative size of supercharger used on the two-cycle and the four-cycle engine, lubrication of the two-cycle engine, location of the rotary valve in the cylinder-head instead of on the side, flexibility or efficient speed-range of the engine, the use of high-speed engines in future private passenger-cars, type of crankshaft used in the Miller racing-car engine, maximum speed of the Miller engine and supercharger, the supercharger drive, probable future of front-wheel drive in passenger-cars, unsprung front-end weight with this type of drive, experiments with worm-drive in racing cars, the use of “doped” fuels, battery versus magneto ignition, steel used in the steering-arms and steering-knuckles, and the like.

i will scan the description from Draper book

https://imagearchive.com/proxy.php?image=http%3A%2F%2Fwww.pattakon.com%2Fte mpman%2FRotary_Valve_Ralf_Watson_2.jpg&hash=007985860988636d3ad38b0a8ae71910
in hindsight i think it is a open disc like a aspin as above rather than a disc valve like a MZ or Kawaski

Flettner

23rd August 2020, 12:05

husaberg

23rd August 2020, 12:42

Bastard Gull.
Stopped selling E85.
So now what, even getting ethanol in 200L drums its $4 per L.
Covid19 hand cleaner is the reason.
Barstards, do I have to brew my own after all bugger it.
I want to run my 'special' engine on this stuff.

from memory most of the ethanol in NZ comes from lactose co
Which will be owned by Fontera
https://nzic.org.nz/app/uploads/2017/10/3H.pdf

this might be what its called now
https://www.lactanol.com/

WilDun

23rd August 2020, 17:17

I assume this thread is more about disscusion on concepts, evaluating running prototypes and theory.
I can show the occasional pictures of my uniflow here but the build pictures I'll take back to the Bucket Foundry, yes?

Yep, good idea, I also had planned to add some stuff there (at the lower end of the scale!) - but too much other stuff going on at the moment.
The foundry thread is a little starved just at the moment and all your info I'm sure would be welcome there - occasionally some people here may need to be directed there when new and interesting foundry stuff and photos come in.

BTW, I believe that our "methylated spirits" is now methanol free and is 100% ethanol now - but I'm sure you know that! - Ethylated Spirits??

Norman

23rd August 2020, 19:27

And others, indeed Norman.
346873 346871 346872
Seriously, I would buy an E-car today if I could have an 800 km range, and charging points without waiting lists everywhere.

I like the pictures there Frits, makes my morning even better!

Personally, I like HEVs better, have a problem with a car filled with 5-600 kg of batteries. The latest I heard was that Cobalt is still needed to make them, and a lot of that comes from Kongo. I do not think even the car manufacturers have the full picture how this is taken up from the ground and subsequent steps. But the process is accepted as long as a signed paper could be shown to them that everything is quite ok..Well, to their defence, the purchasing departments have, since some time, got instructions to dig deeper into their supplier chains, and we will see where that leads.

I famous swedish girl said some time ago that we do not have so much time left to save the planet and we need to do something now! Some think BEVs is the answer to her call. For city environment, it can be good, but to save the planet? I am not too sure. I think BEVs with 500 kg batteries should not be used for example by people having 15 km to work and definitely not be bought to be put in the garage only for Sunday afternoon rides.
Maybe it even should be regulated somehow. Another interesting question is where our older vehicles are ending up? Well, a fact is that a lot of them will live on in Africa for many many years.