John_Forbush wrote:What kind of a sensor would I need to regulate my injector?
Heh.. for electronic fuel injection, you're gonna need the injector (of course), you'll need a crankshaft position sensor which will feed the trigger signal to a controller (which you will also need) , the controller determines when to turn the injector on (based on the trigger signal from crank position sensor), and for how long. Length of time determined by several factors:
1) Fuel Pressure (Can be sensed by a pressure sensor, or can be fixed / assumed at a fixed pressure, which will need to be a closely regulated pressure, can't vary by much or fuel delivery will be inaccurate.)
2) Mass Air Flow Sensor (to tell how much air is flowing into the intake. - Air volume in CFM)
3) Air Temperature Sensor (to tell how dense that air is.- Colder air has more density and more air to burn, and may need fuel enrichment... and if you wanna go a step further, the controller can also turn on a glow plug in the intake "as needed" based on temperature readings, to reduce the fuel demand.)
MAF can be replaced by a TPS (Throttle position sensor) which, because the air volume through the venturi/carburetor (CFM) is known, (and density determined by temperature), throttle position can extrapolate the amount of air flowing by calculating the percentage of throttle opening.
If you want a CLOSED LOOP feedback system that further improves fuel economy you'll need an oxygen sensor in the exhaust to determine how much oxygen is present in the burned exhaust, so it can adapt the fuel trim richer or leaner based on that value.
Knowing all that, it seems kind of amazing how a carburetor can manage ALL of that in such a simple device..
Like I said at the start of the thread - fuel injection is *POSSIBLE* , but as to whether you even want to attempt it, or spend the money on it, is the bigger question. - It is well possible to go simple and simply trigger the injector on and off for a fixed time period, but the engine will not run as efficiently as it will on carburetion.. if it runs right at all.
