Injector timing

[Mazda Ebrahimi]

> 
> 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

Hi Joe,
I think the sample rate of the O2 sensor is dependant on distance and gas velocity from 
the nozzle of the injector to the O2 sensor rather than engine speed.  In other words, 
at 4000 RPM, you should be able to read the sensor more frequently at a higher load 
because gas velocity is higher.  This is especially true if the sensor is at a common 
point and exposed to exhaust from several cylinders.  Also, you have to account for 
sensor aging (slower response time), and error in your calculations.  It's better to be 
a little slow than to read the data too fast.

Best Regards, Mazda