lamda convert reading from volts
Discussion
Narrowband outputs a very non-linear 0-1v
Wideband is usually in the range using a linear 1-3v ( althoguh claimed 0-5v )
They also feature a simulator, to give a non-linear 0-1v output, that the ecu expects to see for its closed loop operation, so you can replace the factory lambda sensor.
In reality, the 0-1v output will go from one extreme of very lean, to very rich within about 0.3v, and canot be relied on as accurate anywhere except at stioch 14.7:1 AFR
Wideband is usually in the range using a linear 1-3v ( althoguh claimed 0-5v )
They also feature a simulator, to give a non-linear 0-1v output, that the ecu expects to see for its closed loop operation, so you can replace the factory lambda sensor.
In reality, the 0-1v output will go from one extreme of very lean, to very rich within about 0.3v, and canot be relied on as accurate anywhere except at stioch 14.7:1 AFR
Whilst the clever people are around ...
One of the things that I picked up from the MS article on WB sensors was that they are affected by all sorts of gases not just oxygen, I got the impression that there was some very clever stuff going on to estimate the AFR from the composition of the exhaust gas. (The article went into some detail about how the sensor had to be calibrated using specific mixes of gas in order to do this accurately.) The article mentioned using CAN to tell the wideband controller when NOX/water injection was active to that it could take account of this in its calculations.
I'm using water injection, is this likely to affect the accuracy of the WB output?
One of the things that I picked up from the MS article on WB sensors was that they are affected by all sorts of gases not just oxygen, I got the impression that there was some very clever stuff going on to estimate the AFR from the composition of the exhaust gas. (The article went into some detail about how the sensor had to be calibrated using specific mixes of gas in order to do this accurately.) The article mentioned using CAN to tell the wideband controller when NOX/water injection was active to that it could take account of this in its calculations.
I'm using water injection, is this likely to affect the accuracy of the WB output?
Not enough to worry about IMO.
Adding various fuels can also effect its output. eg methanol, as each fuel has a different relative AFR.
I think methanol will make it read weak, although that doesnt mean it isnt safe.
Same with LPG, it will read leaner numbers, but in fact they arent really lean. Its just LPG requires different AFR's to petrol. Same with diesel.
When I did my top speed run at Elvington, over 1.25 miles from standing start, my AFR's were around 11.6/11.7 most of the way. This was with injecting a water/meth mix, although I dont actually know what ratio between the 2. It was totally safe, no knock at all, and engine survived. Although 11.7 AFR on petrol is a safe mixture.
Best bit was it resulted in 183mph
>> Edited by stevieturbo on Saturday 6th August 14:30
Adding various fuels can also effect its output. eg methanol, as each fuel has a different relative AFR.
I think methanol will make it read weak, although that doesnt mean it isnt safe.
Same with LPG, it will read leaner numbers, but in fact they arent really lean. Its just LPG requires different AFR's to petrol. Same with diesel.
When I did my top speed run at Elvington, over 1.25 miles from standing start, my AFR's were around 11.6/11.7 most of the way. This was with injecting a water/meth mix, although I dont actually know what ratio between the 2. It was totally safe, no knock at all, and engine survived. Although 11.7 AFR on petrol is a safe mixture.
Best bit was it resulted in 183mph
>> Edited by stevieturbo on Saturday 6th August 14:30
I thought that water DID affect wideband readings. Certainly with megasquirt it will turn off closed loop control when water injection is active.
Talks about it here:
http://megasquirt.sourceforge.net/extra/waterinj.html
Talks about it here:
http://megasquirt.sourceforge.net/extra/waterinj.html
eliot said:
I thought that water DID affect wideband readings. Certainly with megasquirt it will turn off closed loop control when water injection is active.
Talks about it here:
http://megasquirt.sourceforge.net/extra/waterinj.html
The fact that MS goes open loop when the WI turns on implies that WI interferes with the wideband sensor, but I've seen reports on the aquamist forum that some people have tried it and not found any difference. There doesn't seem to be a general consensus though. I guess I'll just have to try it ...
GreenV8S said:
I thought that water DID affect wideband readings. Certainly with megasquirt it will turn off closed loop control when water injection is active.
Talks about it here:
<a href="http://megasquirt.sourceforge.net/extra/waterinj.html">http://megasquirt.sourceforge.net/extra/waterinj.html</a>
The fact that MS goes open loop when the WI turns on implies that WI interferes with the wideband sensor, but I've seen reports on the aquamist forum that some people have tried it and not found any difference. There doesn't seem to be a general consensus though. I guess I'll just have to try it ...
If you have a steady AFR at WOT and good datalogging, just hit the water and see if the afr changes i suppose.
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