Need some clarification on torque stuff

[Blueprint]

Trying to understand what each of these mean and their function. Compared to my dyno graph, im not sure I understand them as good as I thought I did.

Hoping someone can provide some clarification on the following.



1.Scheduled Torque

2.Desired Brake Torque

3. Engine Brake Torque - Is this the actual torque the ECU thinks the engine is making? Im not sure if that is correct. My car sees over 700 ft lb on a mustang dyno. Yet in the scanner I am barely seeing 500.

4. ETC Torque Request- I am assuming this is what the driver is commanding, via the driver demand.

[bbrooks98]

I've been Curious about these too. Bump

[murfie]

Im attaching a chart that compares these four torques to the throttle position for a visual. This is a burnout with throttle input from 0(really 17%) - 50% in first gear. the spike in the middle is a shift to second.

As you can see scheduled and engine brake torque are practically the same as well as ETC and desired are practically the same. So the process goes your foot presses the pedal> engine torque/scheduled reacts> ETC/desired compared > throttle position and other controls (vct, ignition, ECT.) react appropriately.

The yellow and red would be your foot input request to ECU
The blue and green would be the engines reaction from ECU input
The white is the path the throttle body takes

As tires heat up load increases engine makes more torque ETC/ desired raises. Throttle input compensates as pedal input stays relatively the same. All to give a smooth power delivery experience to the driver and passengers.

Engine torque and scheduled are electronic throttle engine driver demand tables. I believe the ECU can choose a value that falls between the low range and engine torque tables up to a certain point for smooth power delivery. Past that point It then uses the engine torque table exclusively. As load increases this value is unaffected.

ETC/ Desired are your torque management calculation and inverse tables. as load increases the torque value increases

Hope this helps

Torque compare.PNG

[tbrtuning]

Thanks. I appreciate your explanation. So the goal is getting your ETC near your engine torque by manipulating the torque tables?

[Blueprint]

Murfie, I appreciate the explation.


I guess I probably shouldnt read too much into it currently. Reason being, I still need to finish properly setting up my driver demand, and torque and torque inverse tables. Thats probably why I am getting odd readings. Oddly enough, my throttle never closes.

My desired,schedule, and ETC all read about the same (700) which is weird considering I make over 700 tq to the wheels. Engine torque never goes above 500.

[murfie]

Thanks. I appreciate your explanation. So the goal is getting your ETC near your engine torque by manipulating the torque tables?

Nope that is the logic in the ECUs job. What happens is with modifications the load / torque relationship changes. This causes an increase in torque error that the logic uses. The goal is to correct the load and torque relationship in the torque calculation and inverse tables. This is done by using the scanner and logging your torque error and plotting it in ect/ desired vs air load graph setup like your calculation or inverse tables. The mapped points weights can add complexity to this because you need to apply correction of the torque error accordingly. Once this is done recalculate the inverse tables so that they are in an inverse of each other again. You don't need to change the driver demand at all. the ecu only uses it for smooth power delivery. Modify it if you want the change the way the engines power is applied for a different feel.

Two ways to increase:
Raise load value for given torque.

Or

Lower torque for given load.

You just need to figure out your cars load/torque relationship.

[GapRider]

This is a crude first attempt at the block diagram for TQ and ETC control only (ignoring VVT, spark and fuel).

It is just a start and I'm hoping that the specifics can slowly be filled it in

PM me if want the file
murfie TQ block diagram.JPG