Oddball engines and prototypes

[WilDun]

Attachment 343890

Cheers, Daryl.

Get a life - I've got 9 - ( 8 after this indignity)!

[ken seeber]

Attachment 343890

Cheers, Daryl.

It's leaning to one side.

Does that make it a CATALIST ????

[Frits Overmars]

Frits, here's the Parsons 2T patent document:
https://patentimages.storage.googlea.../US4924824.pdf

Thanks Michael. This is great reading for the upcoming holidays: nice and scary. Read and shiver.

I have rarely come across a patent with so many ... I try to think of a polite expression, but nothing comes to mind.
To seal the exhaust port, left open when the tilting piston passes over it, there is also a cylindrical piston skirt, hanging from its tilting brother.
But it does not seal sufficiently, so the next step, figure 3, is two semi-cylindrical skirts.
And do these cylindrical skirts take care of the crosshead forces? No, those forces can concentrate entirely on the extremely narrow contact area of the tilting piston.
The seal between cylinder and crankcase is also of an unprecedented ingenious level. As if the required distance between the 'sealing means #42' in figure 3 does not vary considerably with the connecting rod angle. That's not just wishful thinking, it's blatantly ignoring reality.
It seems somebody did not want to design an engine, they just wanted to get a patent. This ain't KISS, it's WHYMISIYCAMIC
(why make it simple if you can make it complicated).

[ceci]

This is great reading for the upcoming holidays: nice and scary. Read and shiver.
.

Everyone has their tastes in reading, mine are the gluttony (supercharging)

https://patents.google.com/patent/US2702533

https://worldwide.espacenet.com/pate...pn%3DGB430490A

[WilDun]

Thanks Michael. This is great reading for the upcoming holidays: nice and scary. Read and shiver.

I have rarely come across a patent with so many ... I try to think of a polite expression, but nothing comes to mind....................

No Frits - it's still "KISS" - (keep inventing silly shit) !

[Frits Overmars]

No Frits - it's still "KISS" - (keep inventing silly shit) !

........

[lohring]

I can't believe the things that have been tried to complicate a very simple engine. The NACA translated a German survey of some of the better attempts. See below. Of course DKW is the poster child for complicated two stroke designs. Today's tuned pipe engines only suffer from packaging issues. Otherwise, they can't be beat for high performance in a low cost and size package. Our 26 cc race engines cost less than $200 out of the box and can produce 4.5 hp stock with the right pipe. Modified they produce over 7 hp. How's that for your hot weedeater?

Lohring Miller

[Pursang]

It's leaning to one side.

Does that make it a CATALIST ????

CATEGORICALLY !!!

Cheers, Daryl.

[WilDun]

Yes,
There is no doubt that chambers are essential in two strokes today and Neil Hintz has more or less proved that with a bit of thought they can be packaged almost as neatly as your average four stroke exhaust, (Neil fiddles with fuel injection and rotary valve inlet timing as well). but chambers, ......... they are mainly all designed to give a better performance and to be most efficient at a certain point in the rev range and everywhere else there has to be compromise! - mostly carried out by mechanisms which "fiddle" with exhaust timing etc.

Chambers are all very good but they do not get us around the mixing of exhaust charge and fresh incoming charge containing oil (whatever we say, or think about that), it is still the reason that two strokes are disappearing fast! ie by legislation produced by ill advised politicians who have no clues about two strokes - their advisers not being familiar with the real 2 stroke facts either!

If we want better performance in the two strokes (for everyday use), then forced charging has to be better in this area (chambers after all are really supercharging using exhaust pulses) and if a properly designed supercharger is integral with the design of the engine (as opposed to a bolted on extra) what is the problem? - cost you say?
I say cheaper than the exotic 4 strokes we have today! - It's only the fear of breaking racing rules lodged in our brains that has prevented this happening!

Also there is the problem of the fresh charge mixing with the outgoing exhaust charge as it enters the cylinder ..... not to mention the uneven cooling effect of the fresh charge and the hot exhaust on the other side of the cylinder, producing distortion and consequently requiring greater clearances.

Again I believe Neil has an answer here - my feeling is, he hasn't had to time to carry on experiments with the opposed piston arrangement he started out with (apparently quite successful)!
I believe that layout, combined with some other innovations I have come up with - (don't want to mention them till I have filtered out some of my more ridiculous notions), which possibly could address some of the problems I mentioned above.

As always I could be wrong and I'm relying on you guys to advise me or point out any obvious blunders with my thinking! ....... but.... explain your thinking! - make it stick!

[Pursang]

I can't believe the things that have been tried to complicate a very simple engine. The NACA translated a German survey of some of the better attempts. See below. Of course DKW is the poster child for complicated two stroke designs. Today's tuned pipe engines only suffer from packaging issues. Otherwise, they can't be beat for high performance in a low cost and size package. Our 26 cc race engines cost less than $200 out of the box and can produce 4.5 hp stock with the right pipe. Modified they produce over 7 hp. How's that for your hot weedeater?

Lohring Miller

That is an Amazing Document!

Every issue clearly defined and described, back in 1934.
Including "the important effect of the exhaust pipes on the process of charging and scavenging"

Pretty much all that has happened since is improvement by refinements in details & metallurgy.
(With some outstanding results)

Cheers, Daryl.

[ceci]

If we want better performance in the two strokes (for everyday use), then forced charging has to be better in this area (chambers after all are really supercharging using exhaust pulses) and if a properly designed supercharger is integral with the design of the engine (as opposed to a bolted on extra) what is the problem? - cost you say?

I agree with you because life has shown me that what you say is true.
This year I made a mistake when acquiring a four-cylinder car with an atmospheric 1200cc. Months later a relative bought another but three-cylinder 900cc supercharged, this is a third more powerful than mine

[Pursang]

OK Will, accepting the Challenge!
(and incorporating what has been know & achieved previously)



Our 'Ideal' 2 stroke Could have a 4 stroke sump, separated from the combustion.

Supercharged fresh air scavenging with turbocharged boost for mid to upper RPM enhancement.

Exhaust by peripheral ports to achieve sufficient STA with maximum working stroke.

Scavenging through 4 poppet valves in the cylinder head, incorporating swirl and/or tumble to fully clear the cylinder.

Electronically controlled direct fuel injection monitoring Throttle position, Head, exhaust & ambient temperature, compression pressure rise, atmos pressure, density & humidity, gradient, braking, cycle "attitude", suspension compression/extension (magnitude and rate of change), front and rear wheel relative rotation, etc. etc.

Could be considered that we are converting the fabulous, but sadly retired, Detroit Diesel into a 'modern' spark ignition engine.

Equivalent power to a 4 stroke at half the rpm (or around 2X at the same rpm)

Cheers, Daryl.

[WilDun]

DARYL & LOHRING
Yes I agree with what you say about the German commentary on two stroke engines - very futuristic thinking for the time.
Most of those predictions actually came to pass and worked well (for many years) - but, although their predictions regarding design were correct, they forgot to consider what people of later generations might be like! - they didn't consider the fickleness of fashionable people or that fashion might play any part at all! .......... but it has done and has just about sunk the two stroke! - sorry to sound like a pessimist, but really that's how it actually is today, not a negative rant about the future!

CECI,
My wife bought a 4 cylinder 1500 Mazda in preference to a turbocharged 3 cylinder turbo charged Suzuki Swift (and it was swift it accelerated like you wouldn't believe!) However we bought the Mazda which was well proven (old school really) but it's good for my wife!
Those tiny turbocharged engines are under too much stress, and it will be interesting to see which lasts longest without attention!

[ken seeber]

That is an Amazing Document!

Every issue clearly defined and described, back in 1934.
Including "the important effect of the exhaust pipes on the process of charging and scavenging"

Cheers, Daryl.

What a good read...…..

[Pursang]

Might work out a little like this!



Easy conversion of an sl/xl air cooled honda single for a 2 or 4 valve proof of concept.
Regrind or cut & weld cam (all inlet) with engine speed (1:1) drive sprocket.

Converted Smog pump or similar for Supercharger driven by the cam, need to source a tiny Turbo.

EFI will probably take me far too long to conquer, maybe i would just use LPG, triggered at exhaust closing position.

Cheers, Daryl.