Charging System: Description and Operation

CHARGING SYSTEM DESCRIPTION AND OPERATION

GENERATOR
The generator features the following major components:
- The delta stator
- The rectifier bridge
- The rotor with slip rings and brushes
- A conventional pulley
- Dual internal fans
- The regulator

The pulley and the fan cool the slip ring and the frame.

The generator features permanently lubricated bearings. Service should only include tightening of mount components. Otherwise, replace the generator as a complete unit.

REGULATOR
The voltage regulator controls the rotor field current in order to limit the system voltage. When the field current is on, the regulator switches the current on and off at a rate of 400 cycles per second in order to perform the following functions:
- Radio noise control
- Obtain the correct average current needed for proper system voltage control

At high speeds, the on-time may be 10 percent with the off-time at 90 percent. At low speeds, the on-time may be 90 percent and the off-time 10 percent.

REGULATED VOLTAGE CONTROL (RVC)
The LY7 engine comes equipped with GEN II regulated voltage control (RVC). RVC is used to more accurately control the amount of voltage put into the battery based upon the battery state of charge (SOC) and battery temperature.

The main components of the RVC system is a new voltage regulator, dash integration module (DIM), and the engine control module (ECM).
- Voltage regulator-Uses a pulse width modulation (PWM) signal on the generator L-terminal circuit instead of a 5-volt reference signal from the ECM to determine voltage output of the generator.
- ECM-Controls the PWM signal to the regulator and provides diagnostics for the generator L-terminal and generator F-terminal. It also provides feedback of the generator F-terminal to the DIM for its calculations.
- DIM-Calculates an estimate of the battery SOC and battery temperature based upon, battery voltage and internal calibrations.

When the DIM has determined what voltage the battery should receive, a message is sent to the ECM. This message tells the ECM what percentage to set the PWM signal at.

With RVC in closed loop control of the generator, it can vary the voltage at the battery from 13.4 volts, battery temperature above 70°C (158°F) and battery SOC 95 percent or higher, to 14.9 volts, battery temperature below -30°C (-22°F) and battery SOC 65 percent or lower. If RVC looses control of the generator because of a failure the voltage regulator will default to 13.9 volts at the battery and function as a normal generator.

CHARGING SYSTEM INDICATORS
The instrument panel cluster (IPC) illuminates the charge indicator when the following occurs:
- The engine control module (ECM)/powertrain control module (PCM) detects that the generator output is less than 11 volts or greater than 16 volts. The IPC receives a class 2 message from the ECM/PCM requesting illumination.
- The IPC determines that the system voltage is less than 11 volts or greater than 16 volts. The IPC receives a class 2 message from the dash integration module (DIM) indicating the system voltage.
- The IPC performs the displays test at the start of each ignition cycle. The indicator illuminates for approximately 3 seconds.

BATTERY NOT CHARGING - 7
The IPC illuminates the BATTERY NOT CHARGING - 7 indicator in the driver information center (DIC) when the ECM/PCM detects a malfunction with the generator output. The IPC receives a class 2 message from the ECM/PCM requesting illumination.

BATTERY SAVER ACTIVE - 27
The IPC illuminates the BATTERY SAVER ACTIVE - 27 indicator in the DIC when the DIM reduces or disables the performance of some vehicle systems in order to reduce the load on the charging system. The IPC receives a class 2 message from the DIM requesting illumination.

BATTERY VOLTAGE HIGH - 8
The IPC illuminates the BATTERY VOLTAGE HIGH - 8 indicator in the DIC when the IPC determines that the system voltage is greater than 16 volts. The IPC receives a class 2 message from the DIM indicating the system voltage.

BATTERY VOLTAGE LOW - 6
The IPC illuminates the BATTERY VOLTAGE LOW - 6 indicator in the DIC when the IPC determines that the system voltage is less than 11 volts. The IPC receives a class 2 message from the DIM indicating the system voltage.

SERVICE CHARGING SYS - 102
The IPC illuminates the SERVICE CHARGING SYS - 102 indicator in the DIC when the PCM/ECM detects a malfunction with the generator output. The IPC receives a class 2 message from the PCM/ECM requesting illumination.