hello,
Ive been read about people trying to turbo there peds and was woundering, if you could run fuel injection on a 2 stoke. I think this make sence since you could inject the fuel in right before the piston closes, thus getting more in? I wouldnt mind hear peoples thoughts about it.
thanks
How is the bottom lubricated? Jim.
One problem with fuel injection above the piston is pressure control..
Fuel is pushed through a fuel injector under some amount of fuel pressure. This amount of pressure PLUS the time the injector is open regulates exactly how much fuel is delivered.
Now if some opposing pressure is pushing against the injector, the injector needs more fuel pressure behind it (or it needs a longer open-time) to provide that correct amount of fuel.
Pressure in the chamber above the piston is high and it constantly varys.. and this pressure resists the fuel pressure.. so fuel delivery is very difficult to control.
Another stumbling block is the tip of the injector cannot withstand the heat of combustion. Wherever it's mounted must be behind some protective barrier.
Honda and a few others have experimented with it.. but by the time the system is working, it's so complex and so expensive it makes the main advantage of a 2-stroke (simplicity) pointless..
oil injector, vespa uses them
how did honda and other get around this?
http://www.motorcycle.com/mo/mcvespa/et2.htmlFYI. Really simple. Jim.
By "it" i was refferring to fuel injection of any kind and i really doubt Honda would go in that direction.. (inject above the piston).
If i recall they did build and sell a 2-stroke that intakes only fresh air directly into the transfer ports.. Air:fuel mix is introduced into the crankcase as normal.. (It has two "carbs" or something like that)
This pure air in the transfers purges the cylinder of exhaust. The point is that this air carrys no fuel.. and any that escapes into the exhaust system doesn't carry fresh fuel with it.
They do have a working throttle body injection system for 2-strokes but again, its complex .. The objective of the system is to regulate fuel precisely and waste as little as possible.. (an emmissions thing.. Its not about fuel economy or a performance enhancing thing)
Search the nets for odd 2-stroke engines.. lots of things have been tried and succeeded.. some are worthy of study especially on older bikes or on other applications.. The newer vehicle stuff is too technologically advanced for practical application by tinkerers, imo.
Trying to put fuel injection and catalytic converters on a 2-stroke put Bimota out of business.If you think you can do it,go ahead.Just keep in mind that a company with the best engineers in the world,and millions of dollars couldn't do it.Things like superchargers,turbochargers,fuel injection,nitrous,and catalytic converters simply don't work on 2-strokes.Everything that can reasonably be done to make a 2-stroke faster and/or cleaner has already been done.Thats why 2-strokes are all being replaced with 4-srtokes.
Steamboat -
Great link!!
Did anyone actually read it?
Looks like Vespa did all this in 1997.
Simply put, the 50cc ET2 has the most sophisticated two-stroke engine ever mass-produced. Period---- Cyberian, This is what I didn't like. Sophistication = expensive. Less expensive than a 4-stroke? Lets wait and see. Jim.
that is very ingenius how they did that.
The real action happens in the cylinder head where a tiny crankshaft drives a small piston.
uh huh .. well.. not exactly the kinda thing you just whip up in the kitchen..
get a bike with oil injection (batavus super sport for example) leave the gas tank empty and put pre mixed fuel in the oil tank
that actually seems dumb enough to work
Hows that pump supposed to know the engine is just starting up (need a 2:1 mixture) or idling (need a 8:1 mix) or running at high speed (need a 13:1 mix) .. it can't .. it delivers the same quantity of liquid at all rpms.
without some feedback sensors and other tricks, the simplest way to adjust delivery of the correct air:fuel mix according to an engine's needs is a carburetor.
uh huh .. well.. not exactly the kinda thing you just whip up in the kitchen..
Absolutely not, but it's nice to see a known maker of two-stroke engines give it a shot and have it work.
May give some incentive to other manufacturers to develop even more systems.
i have a positive outlook on life in general, but from the look of things the 2-stroke is doomed to be crushed under the environmental steam roller .. There is so much money to be made and so much power to be wielded with environmentalism that nothing will stop it.
I'm gonna jump on the bandwagon as soon as i can see a way to make some dough.. maybe get a piece of the contract to recycle that huge moutain of confiscated mopeds and snowmobiles and marine engines..
Wouldnt it make sense just to bore it out and put a bigger piston in it? im just a nub-stick.. but that seems to be a logical solution...
yeah yer right... i was just lookin for a KISS solution to the issue.
joew -
Looks like Aprila has done a lot of R&D on this also.
http://www.speed-sports.com/motorscooters/scooter_models/aprilia_scooters/scarabeo50.html
If you are waiting for the Messiah, I think he/she may have gotten delayed, and we're gonna have to work with what we have for now.
very nice .. $2,600 isn't too bad.
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