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Josh Rowe

2 Stroke That Does NOT Burn Oil

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1 hour ago, Josh Rowe said:

Have you seen anyone try to use direct injection?

As in high pressure directly into combustion chamber like the spark plug.

KTM spent millions of Euros trying this first before settling on the much simpler and almost as effective, TPI. 

Edited by uniflow
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Just to get back to the main point here, if power:weight ratio has to decrease...... so be it. The biggest thing is to reduce toxic emissions whilst keeping the simple and cheap to maintain platform. Anything that gets away from simple and inexpensive maintenance is going to wrong direction. For me anyways.

More power would be great, but that's not the point. It takes about as long to shim a 4 stroke as it takes to replace the whole top end on a 2 stroke. 

FYI, I consider computers and fuel injection something that simplifies things. 

I'll take a 20% loss of power to get a clean 2 stroke enduro bike. Competition use no one cares about emissions. I do care when my family or friends is breathing that shit every weekend we go riding. Let's do what we can, where we can.

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1 hour ago, Josh Rowe said:

I am also wondering how the atomization time of fuel is affected by fuel temperature. AKA, add heat to the fuel prior to injection to reduce the time required for atomization. 

Spare a thought for injection at the transfer port, by this time the air is quite hot, with heat transfer from the crank and such also the heat from compressing this air in the crankcase. Once again win win, better for fuel atomization and good for cooling the charge. 

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26 minutes ago, Josh Rowe said:

Just to get back to the main point here, if power:weight ratio has to decrease...... so be it. The biggest thing is to reduce toxic emissions whilst keeping the simple and cheap to maintain platform. Anything that gets away from simple and inexpensive maintenance is going to wrong direction. For me anyways.

More power would be great, but that's not the point. It takes about as long to shim a 4 stroke as it takes to replace the whole top end on a 2 stroke. 

FYI, I consider computers and fuel injection something that simplifies things. 

I'll take a 20% loss of power to get a clean 2 stroke enduro bike. Competition use no one cares about emissions. I do care when my family or friends is breathing that shit every weekend we go riding. Let's do what we can, where we can.

Why suffer a power loose? If you do it right you can have the best of both worlds. 

Here is an engine I built years ago, nearly another lifetime infact. Uniflow scavenge, fuel air in one end of the cylinder, exhaust out the other, with an air buffer in between. This had high efficiency, (used bugger all fuel) and was able to do this with simple carburetors. Just another solution. 

 

Edited by uniflow

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2 minutes ago, uniflow said:

Why suffer a power loose? If you do it right you can have the best of both worlds. 

Here is an engine I built years ago, nearly another lifetime infact. Uniflow scavenge, fuel air in one end of the cylinder, exhaust out the other, with an air buffer in between. This had high efficiency, (used bugger all fuel) and was able to do this with simple carburetors. Just another solution. 

 

What I'm saying is, while race engines sacrifice fuel efficiency, emissions, and component lifespan for maximum performance...... I am willing to sacrifice performance to reduce toxic emissions.

I agree that assuming it is a zero sum game is flawed. I am just making my personal constraints clear. The primary goal is clean burning.

I am down the ol' rabbit hole.....

 

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Or pull the fuel air somewhere else during transfer, like my HCCI engine, piston in the head creates a volume when needed to stop fuel air spilling out the exhaust, pulls it up into the head area instead. 

With the HCCI the intake needs to be 'open all hours'. 

Edited by uniflow
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15 minutes ago, Josh Rowe said:

Lower emissions, longer engine life, more power, less oil consumption, more reliable, less maintenance. 

I need to figure out how to get in touch with some engineers at BRP

KTM spent millons on DI. 

KTM design engineers own words

" if this is the future of the twostroke, I'd rather ride a fourstroke" he hated fourstrokes. This was reguarding the ridability of the DI engine. 

I think we can do better than this. 

 

Edited by uniflow

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Problem with skidoo style Di on a dirt bike is packaging, producing the electrical power to run it, and the rpm limit.  All that could be overcome but at a cost and compromise.   Manufactures like KTM also want to design and patent their own systems  vs. paying royalty's to BRP on a per bike basis.     Other sled manufactures gave in and just paid them for their RER technology .    

 

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More or less developed for 50cc scooter motors, easy to fuel a small motor that runs wide open all the time.  Little harder to make one run at varied loads and throttle settings .    Simplest FI system I've seen is is inventor Holtzman Acoustic fuel injecton. Same kind of deal, worked good on small motors.  The actual "honk" of  intake tract sound when the throttle opened pushed on a diaphragm attached to a fuel metering needle and jet.  Pure mechanical, it worked pretty good.

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15 hours ago, highmarker said:

More or less developed for 50cc scooter motors, easy to fuel a small motor that runs wide open all the time.  Little harder to make one run at varied loads and throttle settings .    

That is what I have been thinking about. Wondering how responsive it would be.

Really wish I could get my hands on one of KTMs DI test mules. 

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