BMW E61 Sports Wagon 530xiT, Руководство пользователя

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E61 Sports Wagon
DSC/DXC8+ Control Unit
As in the earlier DSC control units, there are two microprocessors incorporated in the add
on DSC8+ control unit. The difference is that in the DSC8 and DSC8+ both processors
do not calculate the same algorithms but rather one processor is responsible for perform-
ing control and monitoring calculations and checking the plausibility of the wheel speeds.
There are also two semiconductor relays integrated in the DSC8+ control unit, one for the
pumpmotor and the other for the solenoid valves.
On exceeding a road speed of 6 km/h, an electronic self-test is started, during which the
pump motor and all solenoid valves are briefly actuated. If the brake is operated at a dri-
ving speed of 6 km/h, as may be the case with "two-foot drivers", the self-test will be per-
formed at a speed of 15 km/h.
The check of the wheel speed signals is already started at a speed of 2.75 km/h.
In connection with the xDrive, the DXC8+ control unit also undertakes the task of calculat-
ing the lockup torque for the multi-disc clutch in the transfer case.
The lockup torque is always optimally set and controlled to suit the corresponding driving
situation.
The drive torque distribution over the front and rear axles is based on the lockup torque.
The lockup torque to be set is derived from the pilot control and from a higher-ranking
traction and vehicle dynamics regulator corresponding to the driving situation.
The DXC8+ control unit sends the data, concerning the lockup torque, on the PT-CAN to
the transfer case control unit VGSG.
Conversely, the transfer case control unit signals the lockup torque actually set as well as
the load on the transmission fluid, electric motor and multi-disc clutch.
Transfer Case (VGSG) Control Unit
The transfer case control unit serves the purpose of regulating the lockup torque of the
multi-disc clutch in the transfer case and therefore to distribute the drive forces between
the front and rear axle corresponding to requirements.
The transfer case control unit receives the necessary torque request from the DXC8+
control unit and adjusts the currently required clutch lockup torque accordingly.
The function required for this task is the transfer case control (TCC). The control and
power electronics circuitry required for the actuator drive is integrated in the transfer case
control unit.
The requirement to set the necessary clutch lockup torque is converted to a correspond-
ing rotary movement of the actuator motor. After turning off the engine, a reference run is
performed in order to be able to assign a corresponding clutch lockup torque to a defined
angle setting of the actuator motor, while also taking into account the effects of wear.
During the course of the reference run, the clutch is fully closed and opened once. The
power intake is measured at the respective angle setting of the actuator motor during the