Electric vehicle drive mode, function

P08.00-2031-75

N47-5ESP control unit

N82/2 Battery management system control unit

N127Powertrain control unit

N129/1 Power electronics control unit

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CAN-C CAN engine compartment

CAN EV Electric vehicle CAN

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Function requirements, general

 Terminal 15 ON

 Selector lever position "D" or "R"

 The terminal status of terminal 15 is transmitted by the SAM control unit via the engine compartment CAN to the powertrain control unit.

The selector lever position transmits the electronic selector lever module control unit via the engine compartment CAN to the powertrain control unit

Electric vehicle driving mode, general points

During driving mode the driver determines the torque request over the accelerator pedal position and the direction of travel over the electronic selector lever module control unit.

The powertrain control unit determines the optimal engine torque relating to the torque request, a lowest possible energy consumption and the current power output capacity of the electric motor drive.

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Function sequence for electric vehicle driving mode

The following signals are read in directly by the powertrain control unit:

- accelerator pedal position from accelerator pedal sensor

- coolant temperature from coolant temperature sensor 1 drive for controlling the thermal management

 Detailed information about the thermal management function is contained in the separate partial function "thermal management function".

The following signals from the power electronics control unit are read in by the powertrain control unit via the electric vehicle CAN:

- status and temperature of the power electronics control unit

- operating mode and temperature of the DC/DC converter in the power electronics control unit

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The following signals from the battery management system control unit are read in by the powertrain control unit via the electric vehicle CAN:

- permissible cell charging voltage

– discharge current

– discharge voltage

- current maximum charge level of high-voltage battery (G5)

- current maximum charge level of high-voltage battery

- actual current of the high-voltage battery

- actual voltage of the high-voltage battery

The following signal are read in by the powertrain control unit via the engine compartment CAN:

- engine braking control active from the ESP control unit

- request of electrical A/C compressor (A9/6) over the heater operating unit / A/C

- crash signal from the restraint systems control unit

- selector lever position of the electronic selector lever module control unit

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In driving mode the powertrain control unit transmits the following signals via the electric vehicle CAN to the power electronics control unit:

- current selector lever position

- ideal engine rpm curve

- engine torque request

- minimal engine deceleration torque

-- minimal cleared out engine torque including deceleration part

- electric motor drive rotation direction request

- electric motor drive dynamic intervention request 1

- electric motor drive dynamic intervention request 2

- electric motor drive dynamic intervention request 3

- electric motor drive nominal rotational speed

- electric motor drive discharge request

- electric motor drive operating mode

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In driving mode the power electronics control unit transmits the following signals via the engine compartment CAN to the powertrain control unit:

- rotor position of the electric motor drive

- current torque of the electric motor drive

- current recuperation torque of the electric motor drive

- current rotational speed and direction of rotation of the electric motor drive

- temperature of the electric motor drive

- current recuperations voltage and recuperation current strength

The signals read in by the power electronics control unit via the electric vehicle CAN serve to actuate the electric motor drive. The electric motor drive is directly actuated by the power electronics control unit.

The signals read in by the powertrain control unit serve to provide feedback about the status and the operating mode of the electric motor drive.

 Sound output in driving mode:

In the vehicle speed range of v = 1 up to 30 km/h a motor noise is output by the electric vehicle sound generator over an integral speaker.

The powertrain control unit transmits the following signals via the electric vehicle CAN to the electric vehicle sound generator to implement the function:

- current selector lever position

- vehicle speed

- pedal value

 The IC (A1) transmits the speed via the engine compartment CAN to the powertrain control unit.