Oxygen Sensor

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Oxygen Sensor

Postby brett nz » Wed Jun 12, 2013 3:23 am

Hi All, having a bit of a play. Single wire 02 sensor. What can you tell me?

In the Toyota Duet 02B file the oscillations go quite small as in .35V to .75V rather than .1 to .85. why is that? Other wise what is the general view on pattern?

Thanks for having a look.
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Toyota Duet 02.JPG
Toyota Duet 02B.JPG
brett nz
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Re: Oxygen Sensor

Postby Alan » Wed Jun 12, 2013 5:23 am

Hi,

Nothing too odd in the waveform. If you look at when you accelerated the sensor gets to nearly 1V (rich) then drops to near 0V (lean).

In other words the sensor can switch froom 0 to 1V. At idle the ECU is responding quickly enough to a rich condition to switch back to lean before the sensor can hit 1V. Perhaps it regards > 0.6V as rich and below 0.4V as lean.

Was there a problem with the vehicle?

BTW the waveform looks very low in resolution (vertical points) and samples (across the screen). Its probably the wrong forum to give advice on how to adjust the settings on scopes other than Pico. Not that we do not want to help everyone - its just we dont know the product. For oxygen sensors its normally best to collect the signal much faster than you think you need - that helps you spot any noise from other components such as igniton and drop outs due to poor connection (it lives in a harsh place). Get the noisy waveform by sampling faster to check this then filter to clean up if you can not clearly see the switching if required.
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Re: Oxygen Sensor

Postby brett nz » Wed Jun 12, 2013 9:27 am

Hi Alan, thanks for having a look. No problem with the vehicle, just having a play trying to learn a bit.

Settings i had are 4 samples 50hz @12 bits. Next vehicle i get on i will try increasing samples and frequency have yet to work out how to do filtering after the fact.

Did a capture of a Ford 4L engine 02 sensor and this was just full of noise even at the same setting as i was using here.

Will have a play and see what i can find.

Thanks again
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