Making use of ADC inputs
#1
Making use of ADC inputs
There are four ADC inputs that are fairly accessible in the sense that I can and already have simulated the original signals (rear O2 and fuel tank temperature), or the signal isn't absolutely necessary for some people (i.e., baro).
1) rear O2
2) ADC_0F (unused ADC input)
3) baro
4) fuel tank temperature (can only be used for temperature)
5) MAF Hz input
The question is what data would you like to be able to log or use to control the motor with these inputs. My personal preference is:
1) rear O2 -> wideband into ECU for logging and/or failsafe boost cut trigger.
2) baro -> baro + ethanol content. I think baro is an important item to use for engine control, so I'd like to make it easy to keep. Using a spare output on the ECU, I can trigger a relay to switch between measuring baro or ethanol content. Both parameters do not change rapidly under any conditions, so they are well suited to alternating measurement.
3) ADC_0F -> exhaust manifold pressure or fuel pressure. Fuel pressure measurement is useful for exploring whether a fuel system is well-designed or operating properly which is handy, but if wideband is being logged, I don't see fuel pressure as being needed for a failsafe. I like the idea of using ADC_0F to monitor exhaust manifold pressure (EMP) as a way to better control VE for SD. EMP would be used as a trim to VE.
4) fuel tank temperature -> I'm not sure what other temperatures would be most handy to log. I could see people wanting to log and perhaps use engine oil temperature or transmission temperature as a failsafe for boost cut. I could write generic code to handle either option.
5) MAF Hz -> turbo speed sensor. I'm not sure if this is possible. Without a doubt, I'd need a frequency divider to make this work.
Anyhow, I'd like to hear that are the parameters you'd like to log and or use to control the motor.
1) rear O2
2) ADC_0F (unused ADC input)
3) baro
4) fuel tank temperature (can only be used for temperature)
5) MAF Hz input
The question is what data would you like to be able to log or use to control the motor with these inputs. My personal preference is:
1) rear O2 -> wideband into ECU for logging and/or failsafe boost cut trigger.
2) baro -> baro + ethanol content. I think baro is an important item to use for engine control, so I'd like to make it easy to keep. Using a spare output on the ECU, I can trigger a relay to switch between measuring baro or ethanol content. Both parameters do not change rapidly under any conditions, so they are well suited to alternating measurement.
3) ADC_0F -> exhaust manifold pressure or fuel pressure. Fuel pressure measurement is useful for exploring whether a fuel system is well-designed or operating properly which is handy, but if wideband is being logged, I don't see fuel pressure as being needed for a failsafe. I like the idea of using ADC_0F to monitor exhaust manifold pressure (EMP) as a way to better control VE for SD. EMP would be used as a trim to VE.
4) fuel tank temperature -> I'm not sure what other temperatures would be most handy to log. I could see people wanting to log and perhaps use engine oil temperature or transmission temperature as a failsafe for boost cut. I could write generic code to handle either option.
5) MAF Hz -> turbo speed sensor. I'm not sure if this is possible. Without a doubt, I'd need a frequency divider to make this work.
Anyhow, I'd like to hear that are the parameters you'd like to log and or use to control the motor.
#2
Evolved Member
On my ADM Evo9, I log boost on pin 92 (MUT38) from an external sensor. We did not get any MAP sensor from the factory.
And log AFR on pin 93, MUT39, which is fuel tank pressure on USDM but is unused on JDM and ADM.
I would be interested in trying to log exhaust gas temp through pin 96, the fuel tank temperature signal on USDM. Once again, it is unused on ADM.
Does pin 96 have a pull-up resistor? And if so, what is its value?
A patch that adds fuel via a 2D table on rising exhaust gas temperature would be of some interest.
There is probably already some obscure code and tables in there already doing something from this input on USDM 8859 rom.
I guess what I am implying is maybe the existing fuel temp code routine (whatever it is) can be hi-jacked into doing this function. A pretty big wish though.
And log AFR on pin 93, MUT39, which is fuel tank pressure on USDM but is unused on JDM and ADM.
I would be interested in trying to log exhaust gas temp through pin 96, the fuel tank temperature signal on USDM. Once again, it is unused on ADM.
Does pin 96 have a pull-up resistor? And if so, what is its value?
A patch that adds fuel via a 2D table on rising exhaust gas temperature would be of some interest.
There is probably already some obscure code and tables in there already doing something from this input on USDM 8859 rom.
I guess what I am implying is maybe the existing fuel temp code routine (whatever it is) can be hi-jacked into doing this function. A pretty big wish though.
Last edited by merlin.oz; Jul 16, 2014 at 12:38 AM.
#3
EGT requires a Type-K thermocouple + amplifier. The output from this setup is a 0-5V signal rather than a resistance, so its not suitable for being logged via the factory temperature sensor inputs. A standard ADC input can be used though. Now that you mention it, EGT is something to think about having available.
#4
Evolved Member
Yes I understand what is required regarding the K-type and an amplifier, my point is if the input to the PCB has a pull-up resistor as I suspect, then a suitable buffer amplifier will overcome that and drive the resistor, provided the amplifier has sufficient drive capacity.
There are plenty of 0-5v output drive (rail to rail) op-amps out there.
There are plenty of 0-5v output drive (rail to rail) op-amps out there.
#5
Evolving Member
iTrader: (2)
Mychailo and Dave, you gurus are raising the bar again.
Although I also studied EE, I keep surprised what gurus here are improving what is already great.
I believe your passion and massive efforts differentiate EVO community from others.
Wideband direct logging without serial cable is a great feature already, and EGT-based AFR enrichment sounds awesome too.
Although I also studied EE, I keep surprised what gurus here are improving what is already great.
I believe your passion and massive efforts differentiate EVO community from others.
Wideband direct logging without serial cable is a great feature already, and EGT-based AFR enrichment sounds awesome too.
#6
Evolved Member
iTrader: (3)
Im Really intrested in the ethanol content. Actually i would like to see an entire flex fuel patch for the evo IX. I have some skills and time to donate to the project, also i have access to a dyno and i have a Evo IX, and i have some tuning experience.
Let me know how i can help, hex disassembly has me stumped and im having some trouble grasping the whole process.
Also why not patch the ECu to take a baro reading when the ignition is first turned on from the MAP. Before you crank the car its at atmospheric pressure. The only issue would be if your doing hill climbs.
Also Baro isnt important if youre speed density. PV=nrt we want the P from behind the intake valve. Baro is only needed for the calculation of the MAF sensor.
Let me know how i can help, hex disassembly has me stumped and im having some trouble grasping the whole process.
Also why not patch the ECu to take a baro reading when the ignition is first turned on from the MAP. Before you crank the car its at atmospheric pressure. The only issue would be if your doing hill climbs.
Also Baro isnt important if youre speed density. PV=nrt we want the P from behind the intake valve. Baro is only needed for the calculation of the MAF sensor.
Last edited by 3SgteGuru; Jul 17, 2014 at 09:14 PM.
#7
Baro at startup is ok, but I'd rather get a periodic measurement. I agree that in the general sense, its not needed for the SD calculation, but turbo efficiency, which depends partly on ambient air pressure, can feedback into overall VE, so I think it has the potential to be a useful parameter to measure and use continuously for VE calculation for people who are travelling across significant elevation changes. And I think it can be helpful for idle.
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#11
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I'm trying to see if there is a way to log oil pressure and what sensor would I need to use, ethanol content, log fuel pressure and oil temp. has there been any update on this? I tried searching but there was no final answer for any of these except ethanol content.
#12
Zeitronix 150 psi gauge pressure sensor.
http://www.zeitronix.com/installatio...allation.shtml
There are a limited number of inputs. Logging three pressure sensors would best be accomplished using rear O2, adc 0F, and fuel tank pressure. This would require some patching to keep the ECU happy.
http://www.zeitronix.com/installatio...allation.shtml
There are a limited number of inputs. Logging three pressure sensors would best be accomplished using rear O2, adc 0F, and fuel tank pressure. This would require some patching to keep the ECU happy.
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