CHARGING SYSTEM


  1. FUNCTION OF MAIN COMPONENTS

    Component Function
    ECM

    • Detects the electrical load condition (blower motor operating or taillight switch on, etc.)

    • Receives signals about the state of the battery detected by the battery state sensor (such as the voltage, current, temperature, State Of Charge (SOC), etc.) and calculates the battery capacity condition.

    • Calculates the request voltage based on the electrical load and the state of the sub-battery and battery and sends request voltage command signals to the generator assembly.

    • Controls the output voltage of the generator assembly.
    Generator Assembly

    • Receives request voltage command signals from the ECM and charges the battery.
    Battery State Sensor Assembly

    • Detects the voltage, current, temperature, State Of Charge (SOC), etc., of the battery and sends the information to the ECM.
    Sub-battery Module Assembly Sub-battery ECU

    • Detects the voltage and State Of Charge (SOC) of the sub-battery.

    • Sends voltage generation request signals to the ECM when the voltage or capacity of the sub-battery is low.

  2. SYSTEM CONTROL


    1. Charging control is performed by the ECM.

    2. The ECM calculates the requested voltage according to the electrical load status and battery status, and sends request voltage command signals to the generator assembly. The generator assembly receives the request voltage command signals from the ECM and charges the battery.

    3. Charging control selects an optimal control mode according to the battery status and vehicle conditions. The provided control modes are basic control mode, supplementary charging mode and refresh charging mode.


      1. Basic Control Mode


        • The ECM decreases the generated voltage during acceleration and increases it during deceleration in order to reduce the amount of engine load caused by the generator assembly, thus improving fuel efficiency.

        • During idling and when driving at a constant speed, the ECM adjusts the generated voltage to bring the current integrated value* closer to the target value.

          Tech Tips

          *: Integrated value of the battery input/output current as detected by the battery state sensor assembly.

      2. Supplementary Charging Mode


        • This mode charges the battery using constant voltage control if the battery capacity is low.

        Tech Tips

        Basic control mode is used when the battery capacity is a specified amount or more.

      3. Refresh Charging Mode


        • This mode suppresses decreases in the battery lifespan by regularly* performing constant voltage control to charge the battery. Also, the operation time of constant voltage control is longer in this mode compared to supplementary charging mode.

        *: When a total of approximately 30 hours has elapsed after the engine is started.

        Tech Tips

        Constant voltage control is also performed for a long time when the battery capacity is low after the battery is replaced or the vehicle is left for a long period of time.

  3. FAIL-SAFE


    1. Due to fail-safe operation, when a sensor malfunctions, basic control is stopped and the system enters constant voltage generation mode. Also, even outside of auxiliary charging mode, due to operating circumstances such as battery condition and electrical load, basic control may be stopped and the system may enter constant voltage generation mode.

      Conditions for Shifting to Constant Voltage Generation Mode other than Auxiliary Charging Mode
      Judgment Condition Reasoning Vehicle Behavior
      Low Battery Capacity If the battery state is bad, the basic control discontinues, and the decrease in battery capacity is prevented. If battery temperature is too low or high, that case becomes cause of battery capacity decrease or battery lifetime decrease. "Basic Control Stops" to "Constant Voltage Generation Mode"
      Low or High Battery Temperature
      Blower Motor Operating (Over High Load), or Taillight Switch On The generated voltage changes due to charging control. As this can impact the operation of electrical devices, the system temporarily stops basic control to prevent any perceived abnormality in the operation of these devices.
      Each Sensor Malfunction In case of sensor malfunction, basic control discontinues, to prevent battery capacity decrease. "Basic Control Stops" to "Constant Voltage Generation Mode (Autonomous Generation Mode*)"
      Generator Assembly Malfunction In case of generator assembly malfunction, basic control discontinues, to prevent battery capacity decrease and to protect the battery .
      Communication Failure (LIN Communication between the Generator Assembly, ECM and the Battery State Sensor Assembly) In case of LIN communication failure between ECM to generator assembly or to battery state sensor assembly, basic control discontinues, to prevent battery capacity decrease and to protect the battery.
      Low Sub-battery Capacity If the voltage or capacity of the sub-battery is low, basic control mode is canceled to suppress reduction of the battery capacity and sub-battery capacity. "Basic Control Stops" to "Constant Voltage Generation Mode"
      Low Sub-battery Voltage

      Tech Tips

      *: In this mode, voltage is generated at a constant level using the IC regulator function built into the generator assembly.