System Overview

System overview

General




This document describes the basic principles of the design and function of the generator (GEN), irrespective of the make.
The generator provides power consuming components with current whilst the engine is running and maintains battery charge. The generator (GEN) is on the front of the engine and is driven from the crankshaft by a Poly V-belt. An automatic belt tensioner is used to adjust the belt tension.
First of all the generator (GEN) creates an alternating current (AC) which is converted to a direct current (DC) in the rectifier bridge.
A charge regulator is welded to the rear of the generator (GEN). However the regulator can be replaced. The carbon brushes are screwed to the slip rings on the rotor on the regulator. The carbon brushes can be replaced separately from the regulator.
The output of the generator (GEN) depends on engine speed. When the engine is idling, the generator (GEN) operates at approximately half of maximum output. When the engine is idling with many power consuming components engaged, the generator (GEN) may be unable to maintain full battery charge. In cold conditions the capacity of the battery to receive charge is lower than at room temperature.
This means that, when the engine is idling for a long period with a large number of power consuming components connected, the battery may discharge.
If the generator charge is cut, the power consuming components of the vehicle are only supplied with energy from the battery, which means that the battery will eventually run flat.
The charge indicator lamp in the combined instrument panel is controlled by the driver information module (DIM) via signals from the controller area network (CAN).

Diagnostics
For 5 cylinder engines
The generator (GEN) and charge regulator is diagnosed indirectly by the central electronic module (CEM) which measures the voltage of the battery whilst the engine is running. If the generator (GEN) stops charging, the voltage in the vehicle will drop. If the voltage drops below 11.5 V for longer than 5 minutes, a message will be displayed in the driver information module (DIM).
For 4 cylinder engines
The generator (GEN) and charge regulator is diagnosed by both the central electronic module (CEM) and the engine control module (ECM).