Charging System Operation: Notes
The purpose of the charging system is to maintain the battery charge and vehicle loads. There are 2 modes of operation and they include:
- Charge Mode
- Voltage Reduction Mode
The engine control module (ECM) controls the generator through the generator field control circuit. It monitors the generator perfor mance though the generator field duty cycle signal circuit. The ECM controls the generator through the generator field control circuit. The signal is a pulse width modulation (PWM) signal of 128 Hz with a duty cycle of 0-100 percent. Nor mal duty cycle is between 5-95 percent. Between 0-5 percent and 95-100 percent are for diagnostic purposes. The following table shows the com manded duty cycle and output voltage of the generator:
| Com manded Duty Cycle | Generator Output Voltage |
|---|---|
| 10% | 11 V |
| 20% | 11.56 V |
| 30% | 12.12 V |
| 40% | 12.68 V |
| 50% | 13.25 V |
| 60% | 13.81 V |
| 70% | 14.37 V |
| 80% | 14.94 V |
| 90% | 15.5 V |
The generator provides a feedback signal of the generator voltage output through the generator field duty cycle signal circuit to the ECM. This infor mation is sent to the instrument panel module (IPM). The signal is a PWM signal of 128 Hz with a duty cycle of 0-100 percent. Nor mal duty cycle is between 5-99 percent. Between 0-5 percent and 100 percent are for diagnostic purposes.