Deactivation Of Hybrid Drive System, Function - GF08.30-P-1004GRH
ENGINE 276.821 in MODEL 166
Function requirements for deactivating a hybrid drive system, general points
- Hybrid drive system "READY"
Deactivating a hybrid drive system - general points
To deactivate the hybrid drive system the ME-SFI [ME] control unit (N3/10) requests switching off of the contactor (A100s1) from the battery management system control unit (N82/2). The ME-SFI [ME] control unit evaluates its status and controls the discharge of the high voltage intermediate circuit via the power electronics control unit (N129/1) and takes back the approval for system readiness.
For this purpose, the ME-SFI [ME] control unit reads in the following signals via the CAN network:
- Power electronics control unit
- Status of the electrical machine (A79/1)
- Voltage status of the intermediate circuit discharge
- Battery management system control unit
- Voltage of high-voltage battery (A100g1)
- Contactor status
- Temperature of high-voltage battery
Function sequence for deactivation of the hybrid drive system
If the conditions described further below are met, the ME-SFI [ME] control unit requests switching off the contactor via the CAN network from the battery management system control unit.
Switching off path
The switching off path is used for very serious system failures (e.g. a CAN network failure) to power down the high voltage on-board electrical system and the hybrid drive. The status "READY" of the hybrid drive system is retracted after powering down, the internal combustion engine is switched off and the vehicle is no longer ready to drive.
If a severe error in the hybrid drive system is detected, the ME-SFI [ME] control unit uses the switch-off path to send a signal to shut down the hybrid drive system to the power electronics control unit.
After successful switching off of the contactor, the battery management system control unit alters the status of the contactor and sends it on the CAN network. In the case of failure of the status signal and message failure, the ME-SFI [ME] control unit sets the status of the contactor to a substitute value.
If information is provided about the contactor being switched off in the event of a crash, the ME-SFI [ME] control unit requests active discharge of the condensers (high-voltage intermediate circuit) via the CAN network from the power electronics control unit.
To ensure discharging of the high voltage intermediate circuit, the power electronics control unit checks the voltages after opening of the contactor and reports these via CAN network to the ME-SFI [ME] control unit. In the case of signal and message failure the ME-SFI [ME] control unit sets the voltage information respectively to a substitute value. If the maximum discharge time does not reach the minimum value of the voltages after the procedure, a fault memory entry takes in the ME-SFI [ME] control unit.
After successful switching off of the high voltage on-board electrical system, the ME-SFI [ME] control unit retracts system readiness of the hybrid drive system. The ME-SFI [ME] control unit transmits this status via the CAN network to the instrument cluster (A1), which switches off the "READY" indication.
After successful retraction of the system readiness and discharging of the intermediate circuit, the ME-SFI [ME] control unit retracts the system readiness "READY" of the hybrid drive system and switches off the internal combustion engine if necessary.
The vehicle is no longer ready to move without the system readiness "READY".
Further conditions for deactivation of the hybrid drive system are documented in the function description "Hybrid drive system monitoring function".
| Electrical function schematic for deactivation of the hybrid drive system | PE08.30-P-2064-97NAH | ||
| Monitoring a hybrid drive system, function | GF08.30-P-5001GRH | ||
| Overview of system components, hybrid drive system | GF08.30-P-9999GRH |