Engine Coolant Temperature Related Configuration Parameters
- Traditionally coolant temperature range was -40..+102C, and had to be selected at firmware upload time.
- Since many engines regularly exceed 102C coolant, installers often cheated and uploaded 1900/256 hexfile instead of 2252/256 so the reading is appr 10C lower around 100..110C (this extended the range to 112C)
- With 1.1.50 or newer firmware, one can select Celsius (not Fahrenheit) based coolant table during firmware upload (eg. 2252/256). This way the maximum coolant temperature is 155C (range is -100C .. +155C). LCD and VemsTune / MegaTune communication was changed to reflect this(and show temperature that matches the internal representation)
The flash table is chosen below in the settings/constants dialog:
Alternatively, the 17-point curve can be chosen. When the 17-point curve is chosen, coolant (and MAT, in a similar fashion) can be configured with a 17 point table. Remember this is with 1.1.50 or newer firmware.
Some values that work for some NTC sensor are noted on the left
- is this the popular 2252 Ohm curve or the curve for slightly higher resistance sensor the firmware used to be released with traditionally ?
- This can be used as a starting curve.
- we should copy files containing config-dump parts to the relevant directory so new entry appears in the dropdown at lest for the most popular sensors.
- some method for temperature curves adjustment needed. 0...16 are ADC values. 0 represents 0ADC or 0V, 16 represents 255 or 5.00V (?) please correct! So two practical and one theoretical method would exist.
- Practically we can measure voltage drop over NTC or PTC and make adjustment when voltage drop mach with one of 17 points. exatly match!, otherwise if make adjustment when raw adc is between two points can lead to unusable curve.
- more comfortable method would be if we can observe direct raw ADC value in tuning program. Can it be done??
- theoretical method if we have access to NTC or PTC resistances vs temperature. We can calculate voltage drop and adc value. Or simply read from old good easytherm/MStoolsII output file. What bias resistor VEMS use? MembersPage/GintsK
While the traditional flash table must be selected at firmware upload time, this 17 point curve can be adjusted later, and easily matched even to special-custom setups without programming knowledge.
to Verify which hexpatch (air,clt) is on the board...
- VemsTune firmware verify function
- select desired air and coolant patch files
- mismatch in page 1-2 means different air-patch file
- mismatch in page 3 means different coolant patch file
- mismatch in page 4-247 means different firmware
[[Manual: Detailed.Sensor.Coolant.Config]]
See also