Generic Sensor Calibration - For fuel temperature adjustment

[stirlsilver]

Hello everyone, I have a bit of complicated problem which hopefully can be solved.

My Configuration (I'll get an MSQ shortly as the car is at another location):
* MS3 running 1.3.2 code
* Car runs on a vapour LPG inject system
* There are two sensors which measures the temperature and pressure of the LPG in the injector fuel rail
* The LPG pressure sensor is a linear 0-5V
* The LPG temperature sensor is a Thermistor (not GM and different to the coolant sensor)
* The LPG pressure & temperature sensors are configured as Generic Sensors in Tuner Studio
* Both sensors are mapped in the Fuel Temperature & Fuel Pressure Adjustment sections in Tuner Studio

My problem is as follows:
* I can easily apply the linear transformation to the LPG pressure sensor - Fuel Pressure Adjustment working OK
* I can't apply a transformation to my LPG temperature sensor - It isn't any of the default types in the transformation pull down menu

I have looked into the custom.ini approach for a variety of my other thermistor type sensors (see below):

Code: Select all

[OutputChannels]
LPGTemp = { 0.000182 * sensor02 * sensor02 - 0.262242 * sensor02 + 100.71 }, "°C" ; ADC to Temp conversion from EGO2 port on MS3X connector
TransOilTemp = { 0.00018 * sensor05 * sensor05 - 0.26634 * sensor05 + 115.87197 }, "°C" ; ADC to Temp conversion from JS4 port on MS3 connector
EngOilTemp = { 0.00018 * sensor06 * sensor06 - 0.26634 * sensor06 + 115.87197 }, "°C" ; ADC to Temp conversion from TinyIOx AD0 port

[GaugeConfigurations]
gaugeCategory = "Custom Gauges"
;Name                 Var           Title                  Units      Lo     Hi     LoD    LoW   HiW   HiD vd ld
LPGTempGauge    = LPGTemp,         "LPG Gas Temp",         "°C",      0,    100,     5,    10,   80,    90, 0, 0
TransOilTempGauge = TransOilTemp,  "Trans Oil Temp",       "°C",      0,    100,     10,   20,   80,    90, 0, 0
EngOilTempGauge = EngOilTemp,      "Engine Oil Temp",      "°C",      0,    100,     10,   20,   80,    90, 0, 0

The above all works fine and I can pull up a gauge to show the LPG temperature in degC. As you can see from the code, what I did was simply set Sensor 2 to be the raw ADC 10bit value and converted it to DegC via the custom.ini

The process all came undone when I went to program the curve for the fuel temperature adjustment. The value that was being looked up here was the ADC 10bit (0-1023) value and not the degC value calculated in custom.ini. So obviously the custom.ini configuration is limited to the gauges only which makes sense.

For a solution I tried to simply code the fuel temperature adjustment table in the raw ADC numbers (0-1023). However as soon as I tried to put in a number greater than 120 it threw an error message about entering a temperature that was too high. I tried searching through the controller ini file to change this set point (clthighlim) but it didn't work.

So I now need help. How can I achieve what I am trying to do? Below are the options I can think of:
1. Change the default transformation in the MS3 for "Same as MAF" to what I need - I don't use a MAF so if it can be changed to the right curve it would be useful. However, I don't know how to change this transformation as TunerStudio only gives me access to the Coolant and Air temperature calibrations
2. Add another transformation option into the pull down list - I couldn't find anywhere in the controller ini file that does this. I suspect the information is all coded into MS3?
2. I apply a Linear calibration which divides the raw number by 10 (0-1023 to 0-102.3) - This would work because it stays below 120, but I loose resolution because the temperature adjustment table does not allow decimals to be entered for temperature and I Really don't want to do that because it is a critical value

Any help??

Thanks,
Stirling

[W126]

Hello Stirling,

the fuel temperature adjustment is almost useless, because the sensor cannot be calibrated.
I made a feature request http://www.msextra.com/forums/viewtopic ... 25&t=60364
but there was not even a reply.
I think only your last option will work.

Jan

[stirlsilver]

Hi Jan,
I know what you mean, since I put up my post I have thought of another way and that is similar to my second item 2. (should have been 3).

I could use the linear transformation which divides the raw number by 10 (0-1023 to 0-102.3). And to get around the inability to enter a decimal figure, I simply insert the % adjustment values which correspond to the nearest whole number So 11.0 (ADC 110), 25.0 (ADC 250),... 100.0 (ADC 1000) etc.

But this is very fiddly and when I come to look at the system in 2 years from now I won't be able to figure out what I did and what all the strange numbers mean!! Hopefully there is a way to program in a decent sensor calibration for a generic sensor - like overwriting the "Same as MAF" data or something like that.

Thanks,
Stirling

[W126]

Hi Stirling,

have you noticed that FW 1.5 now has a custom calibration for one generic sensor ?

Regards,
Jan