Charging System

The PCM  -controlled, or Smart Charge charging system determines the optimal voltage setpoint for the charging system and communicates this information to the voltage regulator. The Smart Charge charging system is designed to set 1 of 7 Diagnostic Trouble Codes (DTCs) any time a charging system fault is present. All of the Diagnostic Trouble Codes (DTCs) can set continuous faults, but not all Diagnostic Trouble Codes (DTCs) set as on-demand faults.

The smart regenerative charge system primary strategy is stored in the BCM  . The BCM  receives all of the important information relating to the battery condition from the battery monitoring sensor via the LIN  . The BCM  calculates and sends the set value needed for the generator charging voltage via the High Speed Controller Area Network (HS-CAN) to the PCM  . The PCM  then adjusts the value received (if necessary) and sends it to the generator via the LIN  . The charging voltage is adjusted depending on various parameters, such as the current level of engine efficiency. The smallest possible set value for the generator voltage is 12.2 volts, while the maximum charging voltage can be anywhere between 14.5 and 14.9 volts. However, when the battery is in a refresh phase, the voltage may occasionally reach up to 15.2 volts. These refresh phases are required when the battery charge status is 80% over long periods of time, which increases the risk of sulfation in the battery cells.

The PCM  simultaneously controls and monitors the output of the generator. When the current consumption is high or the battery is discharged, the PCM  raises engine speed as needed to increase generator output. The generator charges the battery and at the same time supplies power for all of the electrical loads that are required. The battery is more effectively charged with a higher voltage when the battery is cold and a lower voltage when the battery is warm.

The PCM  turns off the generator during cranking to reduce the generator load and improve cranking speed. Once the engine starts, the PCM  slowly increases generator output to the desired voltage.

The PCM  reports any charging system faults and sends a message through the High Speed Controller Area Network (HS-CAN) to the BCM  . The BCM  then sends a message over the Medium Speed Controller Area Network (MS-CAN) to the IPC  , which controls the charging system warning indicator. The status of the PCM  charging system warning indicator message can be confirmed by viewing the PCM  Generator Fault Indicator Lamp (GENFIL) Parameter Identification (PID). Any charging system fault detected by the PCM  results in 1 or more Diagnostic Trouble Codes (DTCs) being set and the GENFIL Parameter Identification (PID) having a status of ON. If equipped with a charging system warning indicator, the IPC  turns the indicator on or off. If equipped with a message center, the IPC  displays the corresponding message to notify the driver of the condition.

Under certain circumstances, the charging system may have a concern but still keeps the battery charged while the vehicle is running. The LIN  is normally used to initiate charging, but the generator can charge with a fault in this circuit. If the engine operates at more than 2, 000 Revolutions Per Minute (RPM) momentarily, the generator self-excites or begins charging on its own. The charging system warning indicator is then illuminated and/or the corresponding message to notify the driver of the condition is displayed and the generator operates in a default mode (approximately 13.5 volts) until the engine is turned off. When the engine is restarted and the engine operates at more than 2, 000 Revolutions Per Minute (RPM) momentarily, the generator again self-excites and again the charging system warning indicator is illuminated and/or the corresponding message to notify the driver of the condition is displayed.