GF42.22-P-1001LEH Regenerative and Hydraulic Brake Mode, Function

GF42.22-P-1001LEH Regenerative and hydraulic brake mode, function

Component Identification:

Function requirements for regenerative and hydraulic brake mode, general
^ Hybrid drive system "READY"
^ Selector lever position "D"
^ Vehicle speed > 20 km/h

Regenerative and hydraulic brake mode, general
The driver's brake command is monitored by the pedal angle sensor and transmitted by the regenerative braking system control unit.

The regenerative braking system control unit communicates permanently over the chassis CAN (CAN E) with the ME-SFI [ME] control unit (N3/10). The ME-SFI [ME] control unit requests the current status of the available regenerative braking torque from the power electronics control unit over the drive train sensor CAN (CAN I).

The regenerative braking system control unit divides the overall braking torque moment requested by the driver according to the driving condition into a regenerative (to be implemented by the drivetrain) part and a hydraulic (to be implemented over the wheel brake) braking torque moment.

If the requested total braking torque can be fully regenerated, then the split into an additional hydraulic portion is no longer required. In this case the deceleration is generated solely by the alternator output. Regenerative braking is not possible at speeds lower than 20 km/h.

As soon as a brake application drops below a speed of 20 km/h, a switchover takes place from regenerative braking to hydraulic braking.

Regenerative and hydraulic brake mode, function sequence
The regenerative braking system control unit actuates the brake pressure simulator valve and the brake pressure is simulated by the brake pressure simulator.

The BAS solenoid valve is actuated by the regenerative braking system control unit, and - irrespective of the pedal position - it boosts the brake pressure for the hydraulic brakes.

The free travel (3) is less than for a brake pedal that has not been actuated.

The distribution of the brake pressures to front and rear axles is realized by a brake pressure distribution in the hydraulic unit traction system.

The regenerative braking torque portion is generated by the integrated starter alternator.

In the event of an emergency stop, a fault in the hybrid drive system or an antilock brake system activation (ABS activation), the braking torque is generated hydraulically only.