Importance of fuel injection sensors??

[samsonite]

I was wondering if anybody could tell me what the most important sensors in a fuel injection system are from most important to least for efficiency. The reason being is I am working on developing an injection system for a 34 cc four stroke motor, to improve the fuel efficiency for an eco super mileage car. My thought was that the Tachometer, O2 ,Throttle Position, and engine temp sensors are probably the most important. If anybody could quantify the importance of the different sensors in a standard injection system it would help me a lot. Thanks

 

[seniorbigs]

This is the way Chrysler taught us regarding the speed density system(no Mass Airflow Sensor).
Primary factors- RPM and coolant temp
Secondary factors- Throttle position, intake air temp, system voltage, change of throttle position.
Fine tune factor- Oxygen sensor
Hope that helps, Mike

 

[schmidtj86]

Paramount - Some form of RPM signal - it can be from the coil, a crankshaft mounted position sensor, anything that can give at least one signal per 2 revolutions.
Also Paramount - Load sensor - it can be throttle position, manifold vacuum sensor, manifold absolute pressure sensor, or mass air flow sensor.
Very important - Temperature of engine - this can be cylinder head temp or coolant temp, or manifold temp. This aids in starting and warm up. Once at steady state warm up, it isn't of much use.
For emissions - Exhaust Gas Oxygen sensor - allows a feedback control system to be used to attain stoichiometry. Allows changes to be compensated for. Allows 3-way catalyst to operate efficiently.
For non-stoichiometric operation with feedback (such as a lean efficient cruise)- A wide range Universal EGO. This will allow rich or lean feed back.
For idle control - an Idle Air Control stepper motor or solenoid.

For a small single cylinder engine, cost is key, so, I'd use a throttle position sensor, and some sort of cylinder head temperature sensor, and calibrate the bejesus out of it, and provide a mixture adjustment knob/screw for the end user to compensate for altitude, production differences, and wear changes. Maybe a cold idle air bybass to allow easier cold starts. This would have to either be electrically operated, or at least known when it is active so the TPS based system can know that there is more air than the Throttle is letting by. If emissions are important or feedback is desired, an oxygen sensor should be used. Non-stoichiometric operation can be achieved, as long as every once in a while it is checked, then %offsets can be used.

I work for a fuel injection company, so if you have any other questions feel free to ask.

Good Luck,
Jeremy