Starter Generator Description and Operation

Starter Generator Description and Operation

Location

The starter generator, also referred to as the drive motor, is located in the engine compartment. The drive motor is mounted to the front of the engine in place of the alternator, directly above the air conditioning compressor. The drive motor is connected to the crankshaft pulley using a specially designed serpentine belt and drive belt tensioner.

Operating Functions

The drive motor is a 3 phase AC induction machine. This device not only serves as a 115-volt AC generator, it is also used to provide engine power assist and to start the engine when in auto-stop mode. The 115-volt AC current flows between the drive motor and the generator control module, also referred to as the starter generator control module, through a three phase cable assembly.

As a generator, the drive motor provides up to 15 kW of AC power to the drive motor control module.

As a motor, the drive motor provides up to 11 kW of electric power assistance and engine starting. The motor receives three phase AC power from the drive motor control module which is internal and part of the generator control module.

The drive motor has 2 internal sensors that are not serviceable, the drive motor position sensor and the drive motor temperature sensor.

The ratio between the drive motor pulley and the crankshaft pulley is 2.38 to 1. The generator control module is capable of checking the integrity of the drive motor belt by receiving an engine RPM input from the ECM over serial data and comparing that against the drive motor speed input signal from the drive motor position sensor.