Start Hybrid Drive System, Function - GF08.30-P-1003GRH

ENGINE 276.821 in MODEL 166 

The subfunction "hybrid drive system start, function" is considered and described from the point of view of the hybrid system.

We will not go into more detail here about internal signals and function sequences of the internal combustion engine.

• Circuit 15 ON
• No crash signal in this ignition sequence
• CAN Bus connection to all high-voltage components actively and trouble-free
• High voltage security checked and released (no crash, no interlock circuit error, no insulation fault)

Starting a hybrid drive system - general points 

The activation function in the ME-SFI [ME] control unit (N3/10) controls precharging of the high voltage intermediate circuit via the power electronics control unit (N129/1) and sends a request to the battery management system control unit (N82/2) to switch on the contactor (A100s1), assesses the status thereof and enables system readiness.

Function sequence start for hybrid drive system 

When the hybrid drive system starts up, the ME-SFI [ME] control unit reads in the requests and signals from the following control units and sensors via the CAN network:

• Fully integrated transmission control unit (Y3/8n4) via the CAN network:
  • Wet clutch status
• Battery management system control unit via CAN network:
  • Voltage of high-voltage battery (A100g1)
  • Temperature of high-voltage battery
• Power electronics control unit
  • Status of the electrical machine (A79/1)
  • Hybrid drive system, status

When circuit 15 is switched on, the ME-SFI [ME] control unit requests the precharging of the condensers (high voltage intermediate circuit) from the power electronics control unit via the CAN network. After precharging and appropriate feedback, the ME-SFI [ME] control unit sends a request to the battery management system control unit to switch on the contactor via the CAN network.

After successfully switching on the contactor, the battery management system control unit sends the status of the contactor to 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.

After successful activation of the high voltage on-board electrical system the ME-SFI [ME] control unit sets the status of the hybrid drive system to "system readiness".

The ME-SFI [ME] control unit transmits this status via the CAN network to the instrument cluster (A1), which displays the "READY" message via the multifunction display (A1p13).

Further partial functions such as the automatic engine start or engine stop are dependent upon further release and system conditions.

Further information concerning the required releases and system conditions for the automatic engine start or engine stop can be found in the following documents:

• Automatic engine stop, function 
• Automatic engine start, function 

	Electrical function schematic for starting the hybrid drive system		PE08.30-P-2056-97NAH
	Automatic engine stop, function		GF08.30-P-3001GRH
	Automatic engine start, function		GF08.30-P-3002GRH
	Overview of system components, hybrid drive system		GF08.30-P-9999GRH