Adaptronic and OBDII codes updates
#42
Bad choice of words on my part - I should've said the injector PW's will suddenly drop for a given MAP/RPM combo when the EGR valve opens, because the exhaust gas will displace fresh air.
So if you open the EGR at say 3000 RPM, your map in theory should have a certain inj PW (and timing) at 2999 RPM, and a different PW (and timing) at 3001 RPM (you get the picture).
The other option is to gradually open the EGR valve from 2500 to 3000 RPM (e.g. 0% duty at 2500 and 100% at 3000). That way there's no step.
So if you open the EGR at say 3000 RPM, your map in theory should have a certain inj PW (and timing) at 2999 RPM, and a different PW (and timing) at 3001 RPM (you get the picture).
The other option is to gradually open the EGR valve from 2500 to 3000 RPM (e.g. 0% duty at 2500 and 100% at 3000). That way there's no step.
I think we need to test this theory well because I could be wrong, but while I had the EGR hooked up, I never noticed a rich/lean spike when going over its activation range.
#46
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i typod. 3000.
I wasn't suggesting to offload the maf mimic, but at that point you now need a bunch of inputs to that circuit. or two 2D outputs (RPM and MAP).
I never had an equation I dont think. I just have the map values.
oh wait, i just realized i made an equation in excel that handles the N/A discontinuity. the spreadsheet is attached. values are in voltages and need to be scaled appropriately into duty cycles or whatever.
#47
I'm thinking of building a uC board that will implement the MAF signal. Among other things, it will improve the factory ECU's idle control, and enable EGR if I wanted to.
For posterity's sake, the original curve fit equation I gave to Matt eons ago which fit data I collected on my TEC3 from the AFM is:
First divide MAP by 100, and call it MAPscaled, and RPM by 7000, and call it RPMscaled (this scales the coefficients to be easier to read, and may make it easier to code if your uC has integer math as opposed to true floating point):
1.6893
+ 1.6504 * RPMscaled
+ 0.90739 * MAPscaled
- 0.88739 * RPMscaled^2
- 0.21516 * MAPscaled^2
+ 1.4595 * RPMscaled*MAPscaled
It may be best to clip MAP to 100 kPa, (MAPscaled to 1) because the factory ECU isn't expecting > 100 kPa's worth of airflow at the various RPM's.
For posterity's sake, the original curve fit equation I gave to Matt eons ago which fit data I collected on my TEC3 from the AFM is:
First divide MAP by 100, and call it MAPscaled, and RPM by 7000, and call it RPMscaled (this scales the coefficients to be easier to read, and may make it easier to code if your uC has integer math as opposed to true floating point):
1.6893
+ 1.6504 * RPMscaled
+ 0.90739 * MAPscaled
- 0.88739 * RPMscaled^2
- 0.21516 * MAPscaled^2
+ 1.4595 * RPMscaled*MAPscaled
It may be best to clip MAP to 100 kPa, (MAPscaled to 1) because the factory ECU isn't expecting > 100 kPa's worth of airflow at the various RPM's.
#50
I'm such a curve-fitting geek. This slightly simpler equation has <1% error vs the original:
1.746
+ 1.639 * RPMscaled
+ 0.6576 * MAPscaled
- 0.8774 * RPMscaled^2
+ 1.465 * RPMscaled*MAPscaled
And pls ignore the curve fits prior to my post #47, I typo'ed.
It takes my prototype 16 MHz Arduino board about 100 us to calculate the above equation, scaled into long integer math.
1.746
+ 1.639 * RPMscaled
+ 0.6576 * MAPscaled
- 0.8774 * RPMscaled^2
+ 1.465 * RPMscaled*MAPscaled
And pls ignore the curve fits prior to my post #47, I typo'ed.
It takes my prototype 16 MHz Arduino board about 100 us to calculate the above equation, scaled into long integer math.
#51
I had to exercise the C-code part of my brain that hadn't been exercised in >15 years!
Maybe we should get Reverant to convert the code from Arduino-C into generic (non Arduino) Atmel code. I can design the PCB layout and build a prototype.
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