Charging System - Operation

OPERATION

The charging system is turned on and off with the ignition switch. This voltage is connected through the PCM and supplied to one of the generator field terminals (Gen. Source +) at the back of the generator. ASD is no longer used for this purpose. The alternator is internally grounded. The NGC regulates the field using Pin 1 of the field connector (High side driver).

The generator is driven by the engine through a serpentine belt and pulley.

The amount of DC current produced by the generator is controlled by the EVR (field control) circuitry contained within the PCM for 2.4/2.4L turbo. This circuitry is connected in series with the second rotor field terminal and ground.

This is done by cycling the ground path to control the strength of the rotor magnetic field. The PCM then compensates and regulates generator current output accordingly to maintain system voltage at the targeted system voltage based on battery temperature. Battery temperature is determined using a mathematical model for the gasoline engines. The model inputs are coolant temp, ambient temp, charge air temp, engine off time, engine speed, and vehicle speed. Coolant temp, ambient temp, and charge air temp are measured by sensors. Engine speed, vehicle speed, and engine off time are standard values monitored by the NGC.

All vehicles are equipped with On-Board Diagnostics (OBD). All OBD-sensed systems, including EVR (field control) circuitry, are monitored by the PCM. Each monitored circuit is assigned a Diagnostic Trouble Code (DTC). The PCM will store a DTC in electronic memory for certain failures it detects. Refer to On-Board Diagnostics in the Electronic Control Modules Powertrain Control Module - Description for more DTC information.

The Check Gauges Lamp (if equipped) monitors: charging system voltage, engine coolant temperature and engine oil pressure. If an extreme condition is indicated, the lamp will be illuminated. This is done as reminder to check the three gauges. The lamp is located on the instrument panel.

Voltage is monitored at B+ stud to insure cable is connected. If cable is loose PCM will shut down generator field. Because of this new feature, pin 2 of the field connector is internally connected to the B+.