Creating a Microchip-Controlled Carburetor: Design Considerations and Components

[GiTS]

What would it take to make a small 2 stroke controlled by microchip? I've been thinking of using the existing carburetor and taking out everything except the throttle and gas lines and adding an improvised hotwire mass flow sensor, PIC microchip, and solenoid powered valve. It doesn't have to be as complicated as the system your car might use, just something to keep the air to fuel mixture consistent except for cold starting and maybe idle. What kind of PIC controller should I use? How many I/O lines should I need and how much memory? Suggestions?

 

[brewnog]

Sounds a nice little project. Can't help you too much with the electronics, but remember that the carburettor isn't just metering the fuel, it's atomising it.

Depending on what the application is, and how much control you want, you'd probably want inputs for engine speed and load. Speed you could take from the flywheel, and load could be inferred from manifold density, guessed-at from throttle position, or measured (hot wire could work very nicely). You might also want some kind of feedback loop based on exhaust O2 or something.

 

[Ulysees]

Why not experiment with this as well.

http://www.kelsey-forums.co.uk/cgi-bin/cmm/YaBB.pl?action=dereferer;url=http://www.megasquirt.info/

 

[Ulysees]

(an experimental Do-It-Yourself programmable electronic fuel injection controller)

 

[GiTS]

What kind of valve should I use to control the gasoline flow? It has to be fairly small, electronically controlled, and precise as well as being able to handle corrosive gasoline.