O2 sensors - sample data
#1
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Here's some sample data as a CSV so it can be graphed in tools such as OpenOffice (in the calc part you can insert a chart).
It doesn't make much sense out of the multiple Time values but it doesn't matter.
To see the waveforms you probably want to set the RPM as a secondary Y axis (or you could scale RPM e.g. divide by 200 - basically anything that lets you peer at the waveforms).
If you read about O2 sensors on the net you'll find the upstream ones have traditionally been the so-called narrow band sensors like the S-Type only has downstream. So, most net data shows waveforms for the (upstream) O2s which swing between about 0.2V and 0.8V.
The S-Type uses another type of O2 sensor upstream, variously known as wide band, wide range, linear etc. Or as AF (air fuel). They provide much more information and quicker (but cost more and need special circuitry). They're also read using extra OBD commands so some OBD tools won't see them.
So, in the CSV data, the B1S1 and B2S1 don't swing much - except when a sudden event occurs. In the data this is where I stuck my foot down or let it up suddenly i.e. rapid throttle change. (The RPM changes happen a bit later, as it takes a little time for the engine to react.)
The B1S2 and B2S2 just wiggle around a bit most of the time, because the upstreams are doing mostly the right thing and the cats are doing the rest. I've had an exhaust gas analysis done which confirmed very low actual emissions.
The forum won't let me attach a CSV so it's a ZIP containing the CSV.
It doesn't make much sense out of the multiple Time values but it doesn't matter.
To see the waveforms you probably want to set the RPM as a secondary Y axis (or you could scale RPM e.g. divide by 200 - basically anything that lets you peer at the waveforms).
If you read about O2 sensors on the net you'll find the upstream ones have traditionally been the so-called narrow band sensors like the S-Type only has downstream. So, most net data shows waveforms for the (upstream) O2s which swing between about 0.2V and 0.8V.
The S-Type uses another type of O2 sensor upstream, variously known as wide band, wide range, linear etc. Or as AF (air fuel). They provide much more information and quicker (but cost more and need special circuitry). They're also read using extra OBD commands so some OBD tools won't see them.
So, in the CSV data, the B1S1 and B2S1 don't swing much - except when a sudden event occurs. In the data this is where I stuck my foot down or let it up suddenly i.e. rapid throttle change. (The RPM changes happen a bit later, as it takes a little time for the engine to react.)
The B1S2 and B2S2 just wiggle around a bit most of the time, because the upstreams are doing mostly the right thing and the cats are doing the rest. I've had an exhaust gas analysis done which confirmed very low actual emissions.
The forum won't let me attach a CSV so it's a ZIP containing the CSV.
#2
![Default](/forum/images/icons/icon1.gif)
And here's a pretty poor graph (see the multiple Time lines, plus I wanted the key underneath and better scaling).
The first (orange) waveform that shoots up is RPM (the right hand Y axis). You can just about see B1S1 and B2S1 blip on the leading and trailing edges of the RPM step.
The X axis is Time in seconds.
The first (orange) waveform that shoots up is RPM (the right hand Y axis). You can just about see B1S1 and B2S1 blip on the leading and trailing edges of the RPM step.
The X axis is Time in seconds.
Last edited by JagV8; 10-10-2009 at 08:56 AM.
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