AFR PID for Tech Edge
:sad: Pulled apart my TE today and soldered in Vout and Grnd connections for the V2 Analog input.
Put it back together and set up a logging session which included the Ben TE; AFR TE; Analog V; and TE V.
The TE V and the Analog V track each other beautifully and if I go to the Tech Edge website and get their curve of V vs AFR for gasoline the AFRs are just what I have been getting from my Tech Edge Display.
However the AFR TE number apparently has nothing to do with anything. That makes me conclude that the TE calc PID is incorrect. Now that is not a big problem as I can log the Analog Voltage and or the TE voltage and simply use those figures.....i.e., stoich is 2.5 v=14.7 AFR; 2.4 V=14.1 AFR; 2.3 V= 13.6 AFR; 2.2 V = 13.1 AFR; 2.1 V=12.6 AFR, 2.0 V= 12.2 AFR; etc.
Simple enough, but I guess I am surprised that the Calc PID does not follow the V to AFR conversion on the Tech Edge website.
Second Edit: Tech Edge apparently does have a Vlin (linear) that would work with the supplied PID. However I tapped into a Vout point on the display so got the nonlinear Vout. For that the calc PID that seems to best fit the Tech Edge curve in the important ranges (12.0 to 15.0:1) and is still simple is {EXT.AV1}*5+2.1. That gives a 14.6 to 1 AFR at the 2.5 v stoich point and gives 12.1 at 2.0v where the Tech Edge website says the AFR is actually 12.17 and at 2.1 v it gives 12.6 which is precisely what the Tech Edge website claims in their data.
So I suppose the moral of the story is that if you can tap the Vlinear output than you can use the supplied PID. If you are just looking for Vout it is nonlinear and needs a custom PID.
Here is the link to the nonlinear curve. http://www.techedge.com.au/vehicle/wbo2/wblambda.htm
Perry
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