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Re: Torque approximation, TCU torque integration

2022-09-17T12:28:21

torque produced being roughly proportional to airmass per cycle

torque produced being roughly proportional to fuel consumption you say? the log does agree.

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Statistics: Posted by AndreyB — Sat Sep 17, 2022 12:28 pm

Re: Torque approximation, TCU torque integration

2022-09-06T01:35:41

https://github.com/rusefi/opendbc/blob/rusefi_prod/vw_golf_mk4.dbc meets https://github.com/rusefi/rusefi_documentation/tree/master/OEM-Docs/VAG/2006-Passat-B6 produces a folder full of MLV logs of OEM engine idling or pulling

https://github.com/rusefi/can-log-tools/tree/main/output

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Statistics: Posted by AndreyB — Tue Sep 06, 2022 1:35 am

Re: Torque approximation, TCU torque integration

2022-09-06T01:04:32

In first iteration: torque at crank = torque produced - torque losses
With
torque produced being roughly proportional to airmass per cycle
and losses being equal or greater to torque needed to sustain idle

So I would go with a first iteration of (airmass/cycle - airmass/cycle(idle)) * correction factor
The correction factor being determined by manufacturer stated max torque at max torque rpm

Statistics: Posted by stefanst — Tue Sep 06, 2022 1:04 am

Re: Torque approximation, TCU torque integration

2022-09-06T00:42:00

the NA version of your engine makes what, 200Nm from 2 liters (~0.6g cylinder airmass max at 100% VE, so ~0.55 with "good" real VE), so that's 363 Nm/gram

Statistics: Posted by mck1117 — Tue Sep 06, 2022 12:42 am

Re: Torque approximation, TCU torque integration

2022-09-06T00:37:31

We already have cylinder airmass. Torque is very nearly linear to cylinder airmass, so you could just configure some value "torque per airmass" in units of Nm per gram.

That is certainly a good enough first order approximation for things like transmission control.

Statistics: Posted by mck1117 — Tue Sep 06, 2022 12:37 am

Re: Torque approximation, TCU torque integration

2022-09-06T00:35:46

Leiderman-Khlystov method of torque approximation by RPM came up which seems like a USSR wisdom?

A person not from forum has contributed two implementations but both seem to not produce realistic numbers for my 2.0T Volkswagen engine.

Lua for both methods is hopeffuly self-explanatory https://github.com/rusefi/rusefi/blob/master/unit_tests/tests/lua/test_lua_Leiderman_Khlystov.cpp

The problem is that both methods produce 2000 RPM torque above max torque from engine inputs. Is that a problem with my implementation or is it that Leiderman-Khlystov is not applicable for GDI forced induction?

Statistics: Posted by AndreyB — Tue Sep 06, 2022 12:35 am

Torque approximation, TCU torque integration

2022-09-06T00:32:25

Two of my test mules are looking for about a dozen of torque-related CAN fields for happy operation. At the moment I am shopping around for any relevant wisdom.

Statistics: Posted by AndreyB — Tue Sep 06, 2022 12:32 am