Let's Talk ALGORITHMS

[Ennis Bragg]

Ok. This info is from Ronald Jurgen's "Automotive Electronics Handbook"
This book is published by McGraw-Hill.ISBN 0-07-033189-8
It is a compilation from various sources.  Chapter 4 is on flow sensors
and was written by Robert E. Bicking of Honeywell, Micro Switch Division.

This is the equation Bicking gives for calculating Mass Flow Rate using
speed-density.

Known		V   = Per-cylinder Nominal Displacement
Known		Ra  = Gas Constant of Air
Measured	RPM = Engine Speed
Measured	Ta  = Intake Air Temperature
Measured	P   = Intake Manifold Pressure
		n   = Volumetric Effieciency
Calculated	Ma  = Mass Flow Rate


	Ma = (RPM)*V*n*P
	      ---------
	      (Ra)*(Ta)

Here are questions I have.

1)  What is meant by the Gas Constant of Air?

2)  How does one determine volumetric efficiency?

3)  Once this equation is worked out, you have a good
    starting point to derive a base pulse width, Right?
    Now how do you factor in things like Throttle
    Position Sensor, and Coolant Temperature Sensor?

All help is greatly appreciated as always.

Thanks

Ennis

-- 
Ennis Bragg	
gt9803a at prism.gatech.edu