Direct Injection Two Strokes

[nimblemotors]

I've been looking into the engine to power my hybrid Porsche Boxster.
The latest and greatest idea is to use a direct injection two stroke motor from a Kawasaki 1100stx DI.
They are rather awesome engines. They fix the majority of problems with 2 strokes. Rather than mix the oil and fuel, they directly inject the fuel once the piston has closed the exhaust port so no fuel goes out the exhaust.
And then spray only oil to lubricate the bearings. This makes the engine 30% more fuel efficient and uses 50% less oil.
The 1.1L 3-cylinder engine puts out 130hp! and is very lightweight, and very small. Compare that to the 55hp metro engine, and it is almost 1/3 the size and 3 times the power.

I don't really need 130hp, and I'm thinking about how I can put the fuel injectors and cylinder head on the 550cc 2-cylinder engine, so it is even smaller and lighter, and still get 80hp.

I'm wondering why they stopped making these, it seems Kawasaki went to a 4-stroke engine after 2004. I know a 4-stroke lets you use a supercharger so you can get even more power from a small package, is that it, or is there something else problematic with the direct injected 2 stroke??
I think they are still used in outboards today.

[Frank Lee]

The snowmobile industry has quite a variety of injected 2-strokers to choose from.

[serialk11r]

I don't know about how bike emissions controls are but I'd get one of those engines! DI 2 stroke is extremely nifty.

For cars at least I think the biggest challenge is knowing how much air is going through the cylinder. Since the exhaust and intake ports are blowing gases through simultaneously you either have really crap scavenging and a lot of exhaust gas leftover, or you don't know how much fresh air is blowing out the exhaust pipe and thus you don't know how much fuel to meter. Certainly there can be some temperature/pressure readings or something used to help the engine decide but they'll never be as accurate as having oxygen sensors giving feedback.

Of course, if you don't give a crap about NOx emissions this is a nonissue

[arcosine]

They use snowmobile engines in Metros at Bonneville.

2 strokes have more emissions and there are new federal standards for off road vehicles like snowmobiles.

[nimblemotors]

Originally Posted by Frank Lee

The snowmobile industry has quite a variety of injected 2-strokers to choose from.

they are air cooled, which makes sense for a snowmobile but not so much for a car, but possible. the jetskis motors are water cooled which I'd prefer.

The interesting thing is they are using turbos on the 2strokes,
AEROCHARGER | Turbo Kits - Ski-doo 800 ETEC
I didn't think it possible, but with direct injection it can work much better.

so a turbo 2-cyl 2-stroke can make quite a lot of power!
So even a 1-cyl with turbo can make 60hp theoretically..

[Frank Lee]

Most are liquid cooled.

[slowmover]

Don't forget the two stroke Detroit Diesel. Several cylinder displacements with from two to sixteen cylinders in those different series. Supercharged, turbocharged, etc.

(Sorry, couldn't resist. A conversation the other day about how awesome were those motors, mounted any which way. Post WWII America sprawl is almost unimaginable without DD powered equipment, from reefer cars to earthmovers to well drilling)

A good thread topic. I can see where this motor type has a wide range of applicability.

.

[cRiPpLe_rOoStEr]

Take a look at the Evinrude E-Tec outboard motors range. You might find something that would serve to your purpose.