Auxiliary Oil Pump

Auxiliary Oil Pump







As the conventional oil pump is powered by the torque converter in an automatic transmission, oil pressure is only generated when the combustion engine is running. However, in a hybrid vehicle, the transmission must also be supplied with oil pressure when the combustion engine is not active, as only then can gearshifts be carried out.

The Cayenne Hybrid therefore features a powerful oil pump installed under the converter bell housing. The oil pump is driven by an electric motor, which is activated by the transmission control unit. The brushless DC motor consists of a rotor with four pairs of permanent magnets and a stator with six solenoid pairs.







In terms of installation position and function, this motor is similar to the motor in the Start Stop system; the increased number of magnet pairs produces a higher torque and thus a higher delivery rate.

Using the position sensors, the rotational speed is used to determine whether there is a fault. If this is the case, start-up of the ATF pump by the combustion engine is requested from the engine control unit via the transmission control unit.