measuring injector in closed loop

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measuring injector in closed loop

Postby Guest » Mon Nov 24, 2008 6:45 am

If a typical injector on time is about 4ms that is 4 thousandth of a second then how much does the ECU richen and lean the mixture in closed loop? If I can see an oxygen sensor cycling then how come a can’t see the injector pattern change?
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IPW

Postby Autonerdz » Mon Nov 24, 2008 4:23 pm

You can see the injector pulse width change in closed loop but the changes are small. You will have to set the scope up with a lot of time on the screen, with maximum samples, so you can capture the injector and the O2 over enough time to see a couple of O2 cycles. You will also need to deploy some resolution enhance to the O2 signal to clean up some of the noise on that signal so you can see it clearly.

Then you can zoom in and use rulers to measure the IPW when the O2 is high and compare to when it is low. Then you will see the difference.

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Postby Dave Hill » Thu Jan 01, 2009 7:21 pm

On some cars the shift in injector pulse width in response to O2 sensor feedback is more pronounced than others. I took this capture way back & I still find it fascinating.

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Hope this helps

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