apalrd wrote:
Yes, definitely NB sensors, all of them (upstream and downstream) were temperature controlled.
For NB calibration, a simple 4-point curve was used to calculate a more linear but not lambda value, which was used directly in a PID control without considering it a 'lambda'. For cylinder balancing, that's probably good enough. If the cylinder is at stoich it should be switching between lean and rich and the values don't really matter much.
I would probably do cylinder balancing using only the NB sensors, so each of them runs a separate control loop to 0.45 volts. Then, make a cylinder correction surface for each cylinder, lower resolution speed vs load (maybe 5x5?) and run the algorithm at each cell. The cell values would be the O2 control value for that cylinder minus the average of all of the O2 corrections (so the average of all of the cylinder tables should be 0). The average of all of the cylinder corrections should be equivalent to the correction that would come from a single wideband, and should be attributed to VE and not a cylinder.
hmmm.....I'm pretty sure non of the aftermarket ECUs do anything but power the heater when the ignition is on. I could maybe look at the current flow though to know the temp....in theory.
A NB output is continuous full rich to full lean, it just has poor resolution and temperature sensitively at other than stoic and but fantastic resolution near stoich any switching that happens on OEM setups is the ECU altering mixture, generally for cat efficiency.
My plan is is to use the NB info for cylinder VE correction tables that I set up as 1/2 the resolution of the main table....but maybe less would do. I'll do the main VE based on the WB sensor then at stoic go in and trim the cylinders using the NB data. This will be done manually for now.
My longer term plan is to use the cylinder data to compensate for TBs drifting out of sync. Enginelab has the ability to save a long term trim values and I thing I can continuously "calibrate the NB sensors using the WB data then auto update the cylinder trims and use that info to create long term trims....I can probably spend the rest of my life "improving the control logic