Suggestions for Fuel Injector

[UVsaturated]

I am considering designing an EFI replacement for my ChinaGirl© carburetor. Does anyone have any suggestions of an OEM injector that is already being used on a small engines for motorcycles, mowers, etc? I'm thinking something small and cheap, and abundant.

Anyone?


Anyone?

 

[Barnfresh]

This company claims to have a plug n play kit for a single cylinder 50cc - 110cc. I don't have any first hand experience with this kit but the price is right. Forum-News-ECOTRONS

 

[Tohri]

I'm keen on something like this as well, but I'd want to run direct injection. And oil injection.

Basically make a super Duper happytime.

 

[UVsaturated]

I'm keen on something like this as well, but I'd want to run direct injection. And oil injection.

Basically make a super Duper happytime.

If one wanted to, they could add a small oil tank anyway and put a metering valve in the system to mix the oil automatically. That way, it would be as convenient as using a 4 stroke and just having to fill the fuel tank with gas.

Are you saying have the injector somehow installed directly in the cylinder head? I know they make those, but I am sure they are different than a standard injector because of the operating temp range.

I was thinking of just making an electronic control circuit with several adjustable parameters; a base/idle mixture setting, a pulse width modulated throttle position sensor, and another sensor for lean/rich depending on engine load (measure manifold pressure). The mixture derived from manifold pressure could just be a pressure regulator that varies according to manifold vacuum or fully electronic. I've seen schematics that people have used a simple 555 timer to operate a typical 12V fuel injector - really cheap. You could also add a simple pot. that works like a choke or go all out and add an engine temp sensor.

 

[Tohri]

Okay, you're not going to get that much benefit from a manifold style injector like you're discribing. Especially if you're injecting premix.

Here's how Rotax does it with their E-600: Fresh air is aspirated into the cylinder instead of fuel/air/oil mix, it's scavenged up through the transfers, and as soon as the exhaust port closes, the fuel is injected directly into the cylinder.
A seperate injector keeps the crank bearings, big end bearing, and wrist pin lubricated directly. And because gasoline vapor isn't moving through the crank case, less oil can be used because it isn't being dissolved and stripped off surfaces.
Furthermore, because fresh air is scavenging the cylinder, higher peak crankcase pressures can be used without sending massive amounts of unburnt charge out the pipe. This brings emissions down while improving power/economy. This large amount of charge cools the cylinder and piston better than a smaller charge, and gives more energy for the pipe to rebound.
And finally, no waiting for fresh charge to flush the cylinder when starting. Direct injected 2 strokes start up on the first pull.