Charge Temperature Estimation

Tuning, troubleshooting and the nitty gritty of using rusEFI to make your engine run nicely!
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Posts: 135
Joined: Thu Jan 14, 2021 10:16 pm

Charge Temperature Estimation

Post by BeerMoneyMotorsports »

image.png (46.99 KiB) Viewed 1112 times
tCharge Settings

tCharge mode

- Air Mass Interpolation

tCharge Increment Limit, deg/sec

tCharge Decrement Limit, deg/sec

RPM + TPS Mode Settings

min RPM min TPS

min RPM max TPS

max RPM min TPS

max RPM max TPS

Air Interpolation mode settings

min tCharge Coeff

max tCharge Coeff

Max Air Flow kg/h
Posts: 141
Joined: Tue Jan 07, 2014 4:38 am
Location: Cincinnati, Ohio
Github Username: blundar
Slack: Dave B.

Re: Charge Temperature Estimation

Post by blundar »

The "big picture" behind tcharge is to try and more accurately predict the temperature of air entering the cylinder, as this is what matters more than the temperature of air wherever the intake air temperature sensor is or the temperature of the coolant sensor.

The broad principles here are that slower moving, less dense air has more of a chance to soak up heat from the intake manifold and cylinder head compared with high-flowrate air where the higher velocity gives less time for heat transfer combined with a larger air mass to dilute the effects of any heat absorbed.

With zero airflow, the temperature of air is assumed to be the temperature of engine coolant. With infinite airflow, the temperature is assumed to be the temperature indicated by the air temperature sensor. In the middle, you have a tcharge model. The idea here is to do a better job of handling temperature variations than is possible with only air temp and coolant temp enrichments by more precisely modeling what is actually happening. This type of model has been common in OE engine management for at least 15-20 years.

I'll let someone else chime in on how the rusEFI settings relate to this framework.
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