ESE's works engine tuner

[teriks]

Frits...

There is a very simple non conventional 2 stroke mechanical fuel injection patented by a Barry Holtzman. Its concept may be applicable for your project...
The unit I had was very compact, yet able to feed a 125cc on methanol. It was roughly the dia of an ink pen and somewhere around 20 mm long. It screwed into a 3mm hole drilled
in the cylinder wall, which was located so the piston uncovered it about 60 degrees atdc. Output of the injector pump was plumbed into the crankcase. Engine compression was sufficient to operate the pump for starting purposes.
In operation each injection pulse is directly proportional to the pressure of the previous power stroke. It functioned remarkably well. I ended up sending it to a customer for testing and never got it back.

The patent number is US 6725845 B2

Here is a link to Google patents.... https://www.google.com/patents/US672...zDBhsQ6AEIIzAB

Kermit Buller

Now that looks like it has some potential!

[Flettner]

Crank case pressure driven diaphragm pumps, pretty common in chainsaw type applications.

I'm struggling to remember details of a fueling system for a 2T rock drill which had to run at any angle...

I had the occasion to be out the back of Siberia some years ago. The Russians had chainsaws with Villiers type engines. I was interested to see that the way the chainsaw was tilted was to tilt the carburetor as well. Butterfly screws and a revolving connecting angle manifold, wow!
Can't remember how the fuel tank worked?



Wonder what thats used for, relieving friction around the houes? Clearly I'm bored

[Frits Overmars]

Frits...There is a very simple non conventional 2 stroke mechanical fuel injection patented by a Barry Holtzman. Its concept may be applicable for your project... The unit I had was very compact, yet able to feed a 125cc on methanol. It was roughly the dia of an ink pen and somewhere around 20 mm long. It screwed into a 3mm hole drilled. in the cylinder wall, which was located so the piston uncovered it about 60 degrees atdc. Output of the injector pump was plumbed into the crankcase. Engine compression was sufficient to operate the pump for starting purposes. In operation each injection pulse is directly proportional to the pressure of the previous power stroke. It functioned remarkably well. The patent number is US 6725845 B2.Here is a link to Google patents.... https://www.google.com/patents/US672...zDBhsQ6AEIIzAB

I love the simplicity of this idea. I fear that the resonant frequency of the spring-piston-spring system (46-50-44 in the patent drawing) may be too low for our 600 Hz (36000 rpm) model engines but I will certainly give it some more thought.

[MotleyCrue]

Crank case pressure driven diaphragm pumps, pretty common in chainsaw type applications.

I'm struggling to remember details of a fueling system for a 2T rock drill which had to run at any angle...

The Holtzman set up uses pressure in the cylinder above the piston so the amount of fuel squirted in is directly related to the load on the engine or at least that is what I remember from 15 or 20 years ago. The magazine tests seemed favorable at the time but I don't think it has been in use for years (could be wrong) so it must not have been all that great.

[Tim Ey]

Hello everyone!

I have a question concerning auxiliary exhaustports:
If you have plugged your wristpin and are on the quest for more exhaust TA - why not make the ports wider than 100% of the Bore?
I have the picture of Frits in mind where the auxiliary ports do not aim directyl to the bore center but more to the C-Port.

I can imagine that the scavenging will not work properly as the A Ports will shoot straight in the auxiliary ports, also the returning fresh gas mixture might swirl the cylinder a lot more than in an "conventional" engine...

So... Has anyone made an computer fluid dynamic of this and it seems to be bullshit? Or why was it never (?) done before?

cheers!
Tim

[teriks]

I love the simplicity of this idea. I fear that the resonant frequency of the spring-piston-spring system (46-50-44 in the patent drawing) may be too low for our 600 Hz (36000 rpm) model engines but I will certainly give it some more thought.

My main concern is what happens if, or rather when, you end up on the lean side of peak power/cylinder pressure.
I'm fairly confident that the resonance frequency can be raised enough with clever design though.

[MotleyCrue]

I think the Holtzman mechanical feedback loop could be tricked into the wrong mixture under certain conditions. The idea of a simple mechanically controlled injection is intriguing though.

Thing is carbs are always a compromise in one way or another yet they do a very good job and in such a simple way.

[SwePatrick]

Mended the dyno today.
Did a couple of pulls.
Brand new sparkplug to read out mixture, really spot on.
Tested a couple of times to se if it was happy with more ingnition, no.
The setting that broke the shaft seems best.
And,, this is the end of the road with this engine, now just racing it left to do.

What about the power then?
Yes!!, i reached 44hp on sprocket.
And at 11400 there is above 27Nm
Only thing i´m not happy with is the dip at ~7500rpm, but I designed the pipe not to build any lowdown torque so i guess i have to deal with it.
Ignitech can sort it out.

screenshot:

Well...

Today i did a couple of pulls.
First i made the clutch not being able to slip cause i found that it was correct that dyno slipped.

Attachment 317666

Then i mounted pvl ignition instead as ignitech is still bugging me.
Made a pull with mild ignition, therefor peak torque is lower.


Attachment 317667

Then i though i´d aim for 42hp at sprocket.
Adjusted ignition a little bit tougher, well..
The engine sounded really nice, really really nice i should say.

Made one more pull,,, *BAM*!!!
Dynoshaft broke *lol*

Attachment 317668

Is this the baddest mt5 engine ever or what?

[wobbly]

Re the idea of increasing the Aux ports wider than 100% of the bore.
This was tested even better than CFD - Jan did it with the RSA on the dyno, lost power.
I believe due to any advantage gained from the extra blowdown area is offset by the much longer path length for the Ex wave
when its past 1/2 way in the bore, and this smears out the pulse amplitude entering the header.

I was asked about Aux ports and spigot design in a PM, and as I cant add pics to a PM, here is the welded duct on a KTM250
with 75% area at the face - 52mm wide by 32mm high, considerably reducing the duct volume in the cylinder just short
of going sonic in EngMod ( PS the floor is 4mm above BDC ).
I added the male spigot, so that the oval to round transition could be made smoothly before entering the pipe header.

[FastFred]

Mended the dyno today. Did a couple of pulls. Brand new sparkplug to read out mixture, really spot on. Yes!!, i reached 44hp on sprocket. And at 11400 there is above 27Nm

44hp, well done, party time ...

[MotleyCrue]

SwePatrick,

Cool. Did you ever post any pics showing your ports? Maybe you did but this thread is so big I have only read a fraction of it. If you did please point us to that for a refresher.

[2005bully]

My main concern is what happens if, or rather when, you end up on the lean side of peak power/cylinder pressure.
I'm fairly confident that the resonance frequency can be raised enough with clever design though.

Very good observation. My intended use of the Holtzman injector was on a clutched fixed gear race kart engine. Unlike most 2 strokes with a transmission, these engines typically operate in an rpm range starting at the torque peak, (point of clutch engagement) followed with all the overwind one can generate. The injector worked remarkably well at all points before torque peak. Then it abruptly stopped pulling with virtually no overwind. After much trial and error I reasoned that since the amount of fuel supplied for each power stroke was determined by the previous combustion event, once the resonances became out of phase and the cylinder pressure dropped a down-ward spiral of lower pressure combustion events followed. Kind of became self governed at the point of peak power.... After quite a bit of trial and error with springs and Bellevue's I moved on to other projects. But kept it in the back of my mind for an application where the engine was operated at rpm's before the power peak.. Current emissions standards have changed everything 2 stroke,, But imagine if you could go back to the early days of chainsaws and weed-eaters, WOW what a slick solution. Self governed, Self compensating for any altitude, and much simpler than any carburetor. Hats off to Barry Holtzman.

One other question raised from working with this unit I hope to answer in due time.... Would it work to use the input from a pressure sensor located in the same position as the Holtzmans injector, as the main input for EFI fuel mapping? Kermit Buller

[TZ350]

Honda MT5 engine 5speed.(6speed breakes very easily i noticed), 132cc, 6 disc clutch, MT8 crankshaft with 110mm samarin rod.(stroked to 50mm), Kawasaki KX 125 -86 cylinder bored to 58mm (Woessner CR144 piston), A lot of porting (199/138/138/140 durations), Derbi design reed. Keihin PWM 40mm, slightly modded. Ignitech ignition, homemade combustionchamber insert. Homemade pipe, Actually built just with 'feeling', no calculations at all.A lot of welding has been done to the crankcase to accept crankshaft and cylinder, Finally coated crankcase to block out some heat from gearbox.

44hp on sprocket, and at 11400 there is above 27Nm Only thing i´m not happy with is the dip at ~7500rpm, but I designed the pipe not to build any lowdown torque so i guess i have to deal with it.

44hp from 135cc with a good usable spread of power, congratulations.

The power dip, we get that too with our different engines, I think it is where the pipe is working against the cylinder and messing up the carburation, we can sometimes improve it with tuning.

[MotleyCrue]

I am looking at removing the aluminum divider entirely, between A and B ports in a cast iron sleeve engine bore 75mm. Does the aluminum divider do anything other than direct and guide the air ? That is, does it also provide any important strengthening/stiffening to the cast iron liner or the aluminum that forms the inside radius of the transfers ? Essentially if I remove the divider will it cause any harm when the engine is run other than mess up the airflow ? I know this is kind of a novice question but I have never needed to remove the entire aluminum divider before, I have always just reshaped dividers.


I will need to replace the divider entirely because its all wrong but its replacement will be epoxy until I get what I want shapewise and I was also going to run it without any divider before doing the epoxy divider just for curiosity's sake, but I'm not curious enough to want to risk damage.

[wobbly]

The ring will probably pop out into the huge transfer holes, and wreak havoc - as there will be no guide radi to ease the ring back into the piston groove.
With no support due to the Ex port hole, as well as the huge transfers, the small areas actually holding the ring in a roundish shape, will be worn very quickly - tears will follow.