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New 2 stroke design

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Posted by: jaguar---------------------

Check out my design of an exhaust valved 2 stroke at http://www.geocities.com/a57ngel/moto/index.html and let me know what you think. The only drawback I can see is that the exhaust valves would get hotter since they are open every cycle instead of every other cycle. But then again they wouldn't be exhausting as much heat because the piston port intake wouldn't allow as much gas/air as a 4 stroke would. If this is a good design then hopefully it will be made use of in order to save the 2 stroke from 4 stroke domination.


Posted by: _JOE_---------------------

I would like to see the cylinder head. 4 ports all going into 1 exhaust pipe? How do you pump the tranny oil to the head?


Posted by: spark250---------------------

It's a good idea and unfortunately it's been done. I have a two stroke engineering book around here somewhere. I think there is a german design from the 30's that had exhaust valves.

I'll see if I can find it.


Posted by: Rich Rohrich---------------------

Some basic research on two-stroke diesel engines will provide you with a number of designs that use exhaust valves with conventional two-stroke port in wall intake passages.

Take heart, lots of great inventors have been forced back to the drawing board when they find they re-invented something. It shouldn't stop you from trying again.


Posted by: _JOE_---------------------

Hey Rich, any idea what the name of these engines are? I'd be interested in doing some research and try and dig up some pics!


Posted by: Cabot---------------------

http://auto.howstuffworks.com/diesel-two-stroke1.htm

Interesting stuff


Posted by: XRpredator---------------------

Quote:
Originally Posted by _JOE_
Hey Rich, any idea what the name of these engines are? I'd be interested in doing some research and try and dig up some pics!

Detroit Diesel. The Screamin' Jimmies (so called because they started out as GM Diesel back in the day). I think they might have quit the 2-strokes back when Penske bought DD, but maybe not, because it was a desirable marine engine.

They were referred to by the number of cylinders and the displacement of one cylinder. i.e. 6-71 or 8V-92 (a V8)

another thing to note: Notice the name "6-71"? Hot rodders should recognize it because that's one of the designations of a supercharger, because most all screamin' jimmies had a blower along with a turbo for fuel scavenging.


Posted by: jaguar---------------------

That page on 2 stroke diesels has the great idea of injecting the fuel after the piston colses the exhaust port on the compression stroke. I think that would be the ideal 2 stroke. Too bad KTM doesn't make one like that.


Posted by: _JOE_---------------------

Looks like the necessity of forced induction to push air into the cylinder makes it quite unpractical for a dirt bike. I'de imagine those engines aren't as responsive as we all expect a bike to be either.

Why couldn't we just inject fuel into a high compression engine? Would it not lite off like detonation?


Posted by: jaguar---------------------

That would make it basically a diesel engine which I believe makes it not too suitable for high rev's because you can't advance the fuel ignition. Rich, please correct me if I'm wrong.


Posted by: dirt bike dave---------------------

Honda won their clsas at Baja on what was basically a 400cc 2 stroke diesel a few years ago. It's interesting stuff. I'm sure there is a lof of info on the web about this mostly forgotten bike.

They devleoped it mainly to be clean burning.

Here is a write up on the Honda EXP2,
http://www.motorcycle.com/manufactu...exp2-14293.html

And a 1998 ride report http://www.motorcycle.com/manufactu...-exp2-15170.htm


Posted by: Rich Rohrich---------------------

Quote:
Originally Posted by jaguar
That would make it basically a diesel engine which I believe makes it not too suitable for high rev's


Audi seems to have worked around a few of the inherent flaws in high speed diesel engines with the V12 TDI engine in the R10. It won't spin like an F1 engine, but it's not too shabby.

http://www.audiusa.com/audi/us/en2/...tdi_engine.html


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Posted by: whenfoxforks-ruled---------------------

Knock it down to a 250, lower the compression a tad, race gas and 927!


Posted by: _JOE_---------------------

I don't know about that, it sounds funny. Nothing like 15k rpm to get the heart rate up.


Posted by: Core87---------------------

interesting theory, I think that having valves in the ports will impeade the flow back or pressure wave from the expansion chamber of 2 stroke design. It would need to have higher compression and a four stroke style pipe as a result. It may be something to look at. Good luck.



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