Injector timing

[Joe West]

 Greetings :

I have a question concerning injector firing. First there has to be a mechanical
reference to sync the injectors to  the cylinders. Lets say a pulse for
TDC of #1 then pulses representing the remaining cylinders. Here is where I
start to wonder, is the injector timing always based upon a fixed starting
point then held for the given pulse width or can the injector timing be
varied from the mechanical ref. via the ECU to adjust for head geometry and
valve overlap etc..? So now the mech. ref. is set "X" number of degrees before
injector firing.

On a interesting side note. Would sampling the data from the oxygen sensor
faster than cylinder firing improve the control for air to fuel ratio.
Taking into account that the exhaust is not steady state. Seems that the 
best time to sample would be as the exhaust pulse passed the sensor if the
sensor had a fast enough recovery time and so on and so on.
Joseph D. West
Electronics Lab. Supervisor
College of Mechanical Eng.
Ohio State University

(614) 292-2845
Fax (614) 292-3163