Exhaust Brake: Description and Operation

GF42.45-D-2010H Engine Braking Regulation, Function


With the clutch engaged, engine braking regulation (MSR) acts on load change processes and rapid downshift processes, in which too high a brake slip is generated at the drive axle in question by the "braking" engine torque which prevails. Engine braking regulation (MSR) prevents the vehicle from becoming unstable even before it starts.By slightly increasing the engine torque here the applied drag torque is equaled and the vehicle is held stable. But in co-operation with the antilock brake system (ABS) this function also improves directional stability and road adhesion in the clutch engaged condition when the brake is actuated.

The ESP control unit (N30/4) evaluates information from the following components:

^ Left front rpm sensor (L6/1)
^ Right front rpm sensor (L6/2)
^ Left rear rpm sensor (L6/3)
^ Right rear rpm sensor (L6/4)

The ESP control unit transmits an engine torque request to the following control units via the Controller Area Network bus Class C (engine compartment) (CANC):

^ CDI control unit (N3/20), with OM 642
^ CDI control unit (N3/21), with OM 646
^ ME-SFI [ME] control unit (N3/23), with M 272