IAT fuel multiplier

[tmbryhn]

Here's a comparison of the default IAT correction table for Megasquirt and RusEFi:

IAT_MS3_vs_RusEFi.png

Question: In the current fuel equations for eg. Speed-Density and Alpha-N, is (1) the raw IAT value taken into account to establish a baseline air density based on eg. the ideal gas law, or (2) does the equations use the IAT correction lookup table for that purpose?

If (2) is the case; would it be a good idea to implement an approximation to the ideal gass law values in the IAT correction table by default similar to the MS method?

[mck1117]

rusEFI uses ideal gas law, but not directly on the intake air temperature. We estimate the temperature at the valve based on a function of IAT, CLT, and airflow. As the airflow slows down, it picks up more heat from the intake/cylinder head on its way by, so it ends up hotter.

This dialog configures that heat transfer:

The table here is derived from the factory GM tune for my V8, and works pretty well.

image.png

tl;dr: you shouldn't need anything other than flat 1.0 in that IAT fuel mult table. It's there if you need it, but you probably don't.

[AndreyB]

https://github.com/rusefi/rusefi/issues/4728 created within the https://github.com/rusefi/rusefi/wiki/Contributors-please-work-smart principle

[tmbryhn]

Thanks Andrey

[AndreyB]

It's hard to notice that help menu but at least some progress I guess

image.png