Deactivation Of Hybrid Drive System, Function - GF08.30-P-1004LFH
Engine 276 in model 222.057/157
Engine 276 in model 222.163
Engine 276 in model 222.173
Engine 651.9 in model 222.004/104
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 system, the CDI control unit (N3/9) (for a diesel engine) or ME-SFI [ME] control unit (N3/10) (for a gasoline engine) sends a request to the battery management system control unit (N82/2) to switch off the contactor (A100s1). The CDI control unit or ME-SFI [ME] control unit assesses its status and controls discharging of the high voltage intermediate circuit over the power electronics control unit (N129/1) and retracts release of system readiness.
To do this, the CDI control unit or ME-SFI [ME] control unit reads in the following sensors and signals via the CAN network:
- Power electronics control unit
- Status of the electrical machine (A79/1)
- Voltage status, 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 CDI control unit or 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 system is retracted after powering down, the 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 CDI control unit or 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 makes it available on the CAN network. If no status signal and message is sent, the CDI or ME-SFI [ME] control unit sets the status of the contactor to a substitute value.
If information about the switched off contactor is present in the event of a crash, the CDI or ME-SFI [ME] control unit sends a request via the CAN network to the power electronics control unit to actively discharge the capacitors (high-voltage intermediate circuit).
In order to secure discharging of the high voltage intermediate circuit, the power electronics control units checks the voltages after opening of the contactor and reports this via the CAN network to the CDI control unit or the ME-SFI [ME] control unit. In the case of signal and message failure the CDI control unit or the ME-SFI [ME] control unit sets the voltage information respectively to a substitute value. If the minimum value of the voltages is not reached after the maximum discharge time, a fault memory entry takes place in the CDI control unit or ME-SFI [ME] control unit.
After successful switching off of the high voltage on-board electrical system, the CDI control unit or the ME-SFI [ME] control unit retracts system readiness of the hybrid drive system. The CDI control unit or the ME-SFI [ME] control unit transmits this status via the CAN network to the instrument cluster (A1), which switches off the "READY" display.
After successful retraction of the system readiness and discharging of the intermediate circuit, the CDI control unit or 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 system is documented in the associated function.
| Electrical function schematic for deactivation of the hybrid drive system | PE08.30-P-2064-97SEH | ||
| Overview of system components, hybrid drive system | GF08.30-P-9999LFH |