Closed loop tuning

[rr]

Thought this might be of interest. . .

I have a good data set of how little the INT needs to change to
swing the O2 sensor from one end to the other. While playing
with the '747 and my TBI setup, I set the proportional gains to
zero. The result is that the ecm will modify the INT in order to
get the O2/fueling to produce x-cnts.

At a steady cruise: 56 mph, 2125 rpm, 44 map, 80deg C coolant,
46 deg SA, VE% ~55, 10% TPS.

The INT would slowly swing between 131 and 137. This would
produce an O2 low of ~190 milli-volts and a high of ~836 milli-volts.
That is not much of a fueling change for that much of an O2 change.
A full cycle from 131 to 137 and back to 131 would take 2 1/2 to
3 seconds.

The transport delay looks to be about 1/2 second. This I derived
from looking at the longest bpw (highest INT), until the O2 sensor
read the highest voltage (richest).

BobR.


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