GM Service Manual Online
For 1990-2009 cars only

Starter/Generator

Instead of a conventional starter motor and generator, the PHT uses a compact 14-kW electric induction motor or starter generator integrated in a patented, space-efficient manner between the engine and transmission. The starter generator provides fast, quiet starting power and allows automatic engine stops and starts to conserve fuel. It also smooths out any driveline surges, generates electrical current to charge the batteries, runs auxiliary power outlets, and provides coast-down regenerative braking as an aid to fuel economy. The starter generator includes a rotor and stationary stator, housed inside the transmission bell housing. The stator is attached to the engine block and incorporates high efficiency/smaller package size coils formed by laser welding copper bars together instead of winding with copper wire. The rotor bolts directly to the engine crankshaft and spins inside the stator. Current flowing through the stator's electric windings generates magnetic forces in the rotor, which causes the rotor to turn, starting the engine. The starter generator is in series with the engine, connected directly to it, so that anytime the engine is turning, the Starter Generator is turning and vice versa. An auxiliary transmission oil pump helps enable the automatic start feature by assuring sufficient line pressure to allow torque transfer immediately upon driver command, when the engine is started.