Convert oxy sensor to a digital signal?
I was wondering what would happen if the oxygen sensor signal were used soley as an input to a voltage switch. This voltage switch would be adjustable, and the output of this circuit would be either 0.1V or 0.9V, with nothing in between. The switching point would be adjustable in 10mV steps.
This would allow us to choose a closed loop AFR with reasonable accuracy and without using a well calibrated guess-o-matic (as the EFIE seems to use) as a tuning device.
The only problem I see is that if the computer actually checks to see if a sinewave exists in closed loop mode, but all the ealier (EECV and earlier) just seem to have a voltage target, and that's it.
thoughts people?
cya Ben
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Convert oxy sensor to a digital signal?
A conventional engine has to switch back and forth from rich to lean condition several time per second to increase the lifespan of the catalytic converters.
Too lean and you over heat the cats, too rich and you plug them with deposits.
Convert oxy sensor to a digital signal?
It would still be in closed loop, but the rich/lean point for closed loop would now be adjustable with good accuracy. Instead of just adding voltage, we would be moving the switching point of the oxygen sensor. Ie if you calibrated your oxygen sensor with a wideband unit (ie saw what your voltages were at certain air-fuel ratios) you would then be able to specify that your new closed loop switch point would be 17:1 (if the narrowband can read that low and the device is accurate enough)
cya Ben
Convert oxy sensor to a digital signal?
[quote="BLSTIC"]It would still be in closed loop, but the rich/lean point for closed loop would now be adjustable with good accuracy. Instead of just adding voltage, we would be moving the switching point of the oxygen sensor. Ie if you calibrated your oxygen sensor with a wideband unit (ie saw what your voltages were at certain air-fuel ratios) you would then be able to specify that your new closed loop switch point would be 17:1 (if the narrowband can read that low and the device is accurate enough)
cya Ben[/quote]
I'm hoping to do just that. The ECM I'm ordering is 'limited' to 25:1. I'm hoping with a WB02 simulating NB02 output I can push it as lean as 30 or 40:1
Convert oxy sensor to a digital signal?
provided the sensor can read that high. The highest reading I have seen from a wideband was roughly 30:1. That was on a diesel doing a power run, it got as rich as 14:1 before EGT's got too high for comfort.
Convert oxy sensor to a digital signal?
Pinhead mentioned this: http://better-mileage.com/memberadx.html in the 'water injection' section. It seems to be something like what you're after, BLSTIC.
Although, the web page seems to have the rich/lean voltages wrong, and I am not sure about the assertion that an ECU will actively seek an average of 0.5V.
Convert oxy sensor to a digital signal?
yeah that's pretty bloody close to what I want.
I wonder how hard it is to have an infinitely adjustable (ie trim-pot) thing like that.