System functions: Gearshift

If a gearshift is initiated in manual or automatic mode, the SMG control unit will actuate the corresponding solenoid valves in the valve block.

The pressurized hydraulic fluid flows into the clutch actuator and opens/closes the clutch.

At the same time, the SMG control unit sends information to the DME control unit that a gearshift has been initiated and that engine torque must be reduced.

In the next step, the gearshift and selector angle actuator is actuated. At the same time, the gearshift and selector angle actuator executes the forward/backward movement of the selector shaft, and if necessary turns the selector shaft.

During the gearshift, the engine speed may be raised as required to allow the clutch engagement to be completed more quickly and more smoothly.

When the gear is engaged, the clutch will automatically close.

The SMG control unit receives the precise clutch position from the clutch travel sensor.

After the gear change, the solenoid valves are actuated without the use of current.

The course of the entire gearshift depends on the accelerator pedal position, road speed, engine speed and other factors (e.g. engine oil temperature).

Just before the vehicle reaches a standstill, the SMG will shift into 1st gear and open the clutch. The transmission of power between the engine and transmission is broken.

Gearshifts that would result in an excessively high or low engine speed are suppressed.