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M800 engine brake selector switch

PostPosted: Tue Sep 21, 2021 11:33 pm
by Shuma- gorath
Hi, is the m800 capable of multiple engine braking maps that can be selected using a switch? Pretty much the same way you can select different levels of traction control? Thanks for the help.

Re: M800 engine brake selector switch

PostPosted: Wed Sep 22, 2021 8:37 am
by David Ferguson
What would be unique in your "braking maps"? Ignition timing in overrun conditions? How much the throttle is closed on DBW setups? Something else?

Re: M800 engine brake selector switch

PostPosted: Wed Sep 22, 2021 10:38 am
by Shuma- gorath
I would use it to adjust the butterflies in the throttle bodies to subtract engine brake. Mainly to be used for when the tire starts to go off.
This is for a motorcycle application.

Re: M800 engine brake selector switch

PostPosted: Wed Sep 22, 2021 10:49 am
by David Ferguson
I believe what you want to achieve is doable, by selecting the switch setting as one of the axis on a table. We need a little more detail on the hardware you have to control the throttle position. Are you using Drive-By-Wire and servo motor throttle bodies, or do you have some other actuator that controls the throttle stop? Tell us how that is wired / controlled. So we an identify the correct table to configure.

Re: M800 engine brake selector switch

PostPosted: Wed Sep 22, 2021 11:04 am
by Shuma- gorath
Awesome, thanks.
I am using a fbw, servo motor throttle bodies.

Re: M800 engine brake selector switch

PostPosted: Wed Sep 22, 2021 12:14 pm
by David Ferguson
I have attached a DBW configuration showing what I think you need to do.

- First configure one of the User Channels (I used User 1) for your brake switch. I configured it for a 6-position pot. See Adjust->Sensor Setup->Input Setup...->User tab. Note the calibration table that converts the pot voltage into a value of 0-5.

- Now configure the Functions->Drive By Wire->Comp table to use User 1 as one axis, and Throttle Pos Driver as the other axis. I set the values on the axis to match the user 1 output values, and the areas where the driver has essentially closed the throttle. So now depending on the switch setting, and the throttle position there will be additional throttle requested when the throttle is closed.

Concerns: this might affect the idle control, but you will have to test and see.

Hope this helps

Re: M800 engine brake selector switch

PostPosted: Wed Sep 22, 2021 12:25 pm
by Shuma- gorath
That's great thanks, I'll give it a try and let you know how it turns out. Thanks again for the help.