DBW Servo Model Parameters to fix lurching

[jcolley]

Have a very lightweight vehicle with a large torque motor. Low RPM in 1st, 2nd, and third gear put enough accel on the car that the driver's body mass pulls his foot and makes smooth throttle application challenging if not impossible.

Have implemented a 3d pedal translation to flatten throttle curve under 3k RPM and that helps some. Dialing in fuel film helped a lot. Trying to get the last bit sorted within M1 Tune without resorting to writing a sort of dashpot delay in Build for the pedal value.

Would altering the Throttle Servo "Model", "Delay", and "Time Constant" a bit assist in damping the pedal value to actual throttle blade movement?

Porpoising.JPG (213.94 KiB) Viewed 10931 times

[Stephen Dean]

I would look more at the Ignition Timing in that engine speed/load range and see if pulling some out will help soften the engines response in the low load conditions.

[Mobne]

I would look more at the Ignition Timing in that engine speed/load range and see if pulling some out will help soften the engines response in the low load conditions.

I have the same issue, where the body movement of the driver after a gear change or start from 0kmh can make the foot do unwanted throttle movements that upsets the whole car.

Is it possible to do a throttle vs pedal curve for each gear?
So first gear will have a different throttle curve compared to higher gears where this isnt an issue?

Or do you just tune the throttle so movements below like 50% is really unlinear?

[Stephen Dean]

Hi,

Do you have a Gear Position Sensor in the vehicle? If you do, you could splice the signal from the sensor into a driver rotary switch input resource and use this with the Throttle Pedal Translation table.

[Mobne]

So this must be done by "hard wiring it"?

Looks like the software does not alow me to use a signal from the gear sensor to a rotary resource also.
I don't have a free analog input to spare for this atm.

Is there a reason you are not allowed to splice a signal in the software or allocate an "function" as the resource?

Inputs i have free and not using is.

Lambda narrow 1-2
Knock 3-4

So the next question in line is if this hard coded inputs can be used as analog inputs 0-5v?

[David Ferguson]

The knock inputs can be used as 0-5V inputs according the the M1 ECU Hardware manual.

The Lambda Narrow inputs can be used for 0-6V, so those are suitable as well.

[Mobne]

The knock inputs can be used as 0-5V inputs according the the M1 ECU Hardware manual.

The Lambda Narrow inputs can be used for 0-6V, so those are suitable as well.

Awesome!

But still, this need to be hard wired? There is no possibility to do it with the signal that’s already in the ecu from the gear sensor?

[Stephen Dean]

You can do it with CAN if you have a MoTeC Dash.

[Mobne]

Yes I have c127.

Would you mind pushing me in the right direction how to?

[MikeD]

You would create a CAN transmit message (with "Gear" as the content) from the C127 which can then be received by the M1 on a receive slot (using matching CAN ID and byte position on both the transmit and receive part).

And you would assign the driver rotary switch resource to use this CAN input... done.

If you are not sure how to do this then you might post your C127 and M1 config so that someone may be able to help you to set it up.

PM me if you need specific help.

regards,
Mike