STOP AND START


  1. FUNCTION OF MAIN COMPONENTS

    Component Function
    Engine Stop and Start ECU Sends either an engine stop or restart signal to the ECM according to the signals from each sensor and switch.
    Engine Stop and Start ECU Backup Boost Converter

    • Supplies battery voltage to help make up for the voltage drop that occurs when the engine is restarted, preventing the operation of various systems from being interrupted due to low battery voltage.

    • Supplies battery voltage to the oil pump with solenoid assembly.
    Park/Neutral Position Switch Assembly Detects whether the shift lever position is in park/neutral and sends a signal to the engine stop and start ECU.
    Vacuum Sensor Assembly Detects the brake booster vacuum pressure and sends a signal to the engine stop and start ECU.
    Hood Lock Assembly Engine Hood Courtesy Switch Detects whether the hood is open or closed and sends a signal to the engine stop and start ECU.
    Front Door Courtesy Light Switch Assembly (Driver) Detects whether the driver door is open or closed and sends a signal to the engine stop and start ECU via the main body ECU (multiplex network body ECU) via CAN communication.
    Front Seat Inner Belt Assembly (Driver) Front Seat Belt Buckle Switch (Driver) Detects whether or not the driver's seat belt has been fastened, and sends a signal to the engine stop and start ECU via the main body ECU (multiplex network body ECU) via CAN communication.
    Air Conditioning Amplifier Assembly Sends the outside temperature signal and engine restart signal to the engine stop and start ECU.
    Ambient Temperature Sensor (Thermistor Assembly) Sends an outside temperature signal to the air conditioning amplifier assembly.
    Combination Meter Assembly Stop and Start Indicator Light

    • Turns on when the engine is stopped due to stop and start control.

    • Blinks to inform the driver that the idling stop is canceled and the engine will restart when the driver door is opened.
    Stop and Start Cancel Indicator Light

    • Turns on to inform the driver that the system has been disabled when stop and start system operation is prohibited by the stop and start cancel switch.

    • If a system malfunction occurs and operation frequency of the starter assembly is over the threshold, the stop and start cancel indicator light blinks to inform the driver.
    Multi-information Display

    • Displays information based on the selected display mode. One display mode shows the current idling stop time, the idling stop time since the engine switch was turned on (IG) and the total idling stop time since the last time the idling stop time was reset. The other display mode shows the current idling stop time, the fuel consumption amount since the engine switch was turned on (IG) and the total fuel consumption amount since the last time the idling stop time was reset.

    • Displays the settings of the stop and start system or warning information, etc.
    Combination Switch Assembly Stop and Start Cancel Switch Operation of the system can be canceled by pressing the stop and start cancel switch. Pressing the switch again or turning the power source off and back on restores the operation of the system.
    ECM

    • Sends various information about engine conditions to the engine stop and start ECU.

    • Based on signals from the battery sensor (battery state sensor assembly), determines whether the battery installed on the vehicle is a specified or non-specified battery, and sends the determination result to the engine stop and start ECU.
    Brake Actuator Assembly Skid Control ECU Sends a vehicle speed signal to the engine stop and start ECU.
    Airbag Sensor Assembly Sends airbag deployment information in the event of a collision and a deceleration signal to the engine stop and start ECU.
    Main Body ECU (Multiplex Network Body ECU) Sends a front door courtesy light switch assembly signal and front seat belt buckle switch RH signal to the engine stop and start ECU.
    Power Steering ECU Assembly Sends an electrical power steering assist signal to the engine stop and start ECU.
    External Backup Boost Converter (Eco Run Vehicle Converter Assembly) Supplements the voltage drop when the engine is stopped to stabilize the audio output.
    Battery Sensor (Battery State Sensor Assembly) Detects the battery charging and discharging amount and sends a signal to the ECM.
    Stop Light Switch Assembly Detects a brake pedal released condition and sends a signal to the engine stop and start ECU via the ECM.
    Accelerator Pedal Sensor Assembly Detects an accelerator pedal opening angle and sends a signal to the engine stop and start ECU via the ECM.
    Crank Position Sensor Detects the crankshaft angle when the engine is stopped and sends this information to the ECM.
    Transmission Valve Body Assembly Oil Pump with Solenoid Assembly Holds the ATF pressure during idle stop.
    ATF Temperature Sensor Detects the ATF temperature.
    Engine Coolant Temperature Sensor Sends the coolant temperature to the engine stop and start ECU via the ECM.
    Generator Assembly Sends the generator assembly generation condition to the engine stop and start ECU via the ECM.

  2. SYSTEM CONTROL


    1. Early Stage Injection Control


      1. Early stage injection control shortens the time it takes the engine to restart after the stop and start system stops the engine, thus allowing smooth initial acceleration.

      2. The ECM memorizes the crankshaft angle detected by the crank position sensor when the engine is stopped by the stop and start system.

      3. The ECM judges the injection required and decides which cylinder to ignite when the driver does restart operation. The ECM then uses this information as it starts the engine.

        A001HCHE05

    2. Hill-start Assist Function


      1. The driving force (creep phenomenon) of a former AT vehicle is regulated by depressing the brake pedal while stopped, and the driving force is transmitted by releasing the brake pedal when starting the vehicle. However, when starting a stop and start system equipped vehicle with its engine stopped due to the activation of the idle stop function, there is a short time delay before the driving force is generated as the engine will start after the brake pedal is released.

      2. The hill-start assist function is a system to assist starting of a stop and start system equipped vehicle on a slope to deal with the situation described above, retaining the brake hydraulic pressure until sufficient driving force is generated.

    3. System Prohibit Control


      1. For safety, battery protection, comfort and ECU learning reasons, the engine stop and start ECU prohibits stop and start system operation if any one of the following conditions is met.

        Prohibition Reason Condition
        Safety If the engine is started with the hood open, such as when jump starting, engine restart operation cannot be ensured. Therefore, stop and start system operation will be prohibited. The operation of the system will be restored on the next trip.
        If the driver door or hood is opened before the engine stops, stop and start system operation will be prohibited for safety reasons.
        The brake booster vacuum is insufficient.
        The driver seat belt is unfastened before the engine stops.
        The engine catalyst is being quickly warmed up.
        Battery Protection While recharging, stop and start system operation will be disabled. The recharging continues for 0.5 to 1 hour, and is carried out approximately every about 30 hours or driving.
        If the idle stop rate becomes higher than a predetermined value, stop and start system operation will be disabled.
        If the battery voltage becomes low and the battery integrated current value drops to below the threshold value, stop and start operation will be disabled.
        Comfort If the air conditioning is on when the outside temperature is high and the evaporator temperature is high, stop and start system operation will be prohibited.
        If the air conditioning is on when the outside temperature is low, stop and start system operation will be prohibited.
        If the heater is on when the outside temperature is low and the engine coolant temperature is low, stop and start system operation will be prohibited.
        If the front DEF switch and blower switch are on, stop and start system operation will be prohibited.
        ECU Learning ECU learning is not complete.*
        Operation If the vehicle is stopped while the steering wheel is being operated, stop and start system operation will be prohibited.

        *: If the value learned by the ECU has been cleared by disconnecting the battery or for another reason, stop and start system operation will be prohibited until ECU learning is complete.

    4. Warning Control


      1. If any of the following operations are performed while the engine is stopped due to system control, the system will not restart the engine. The driver will be warned by a buzzer, or the engine will be regarded as stalled or will be restarted.

        Operation Warning Control
        Hood is opened. The engine status changes to 'stalled' or is restarted.
        Driver seat belt is unfastened. The engine is restarted.

    5. Operating Conditions at Engine Stop and Restart


      1. The engine may stop if all of these conditions are detected.

        Item Operating Condition
        Idle Stop Engine Coolant Temperature 40°C to 105°C (104°F to 221°F)
        ATF Temperature 25°C to 112°C (77°F to 233.6°F)
        Driver Door Closed
        Brake Booster Vacuum Sufficient brake booster vacuum
        Stop and Start Cancel Switch Off condition
        Road Gradient -8° to 8°
        Vehicle Speed Vehicle speed changes from a constant speed to 0 km/h.
        Engine Speed 1250 r/min or less
        Shift Lever Position P, D
        Driver's Seat Belt 3 seconds or more elapse after the seat belt is fastened.
        Drive Mode ECO or NORMAL mode
        Engine Hood Closed
        Battery Voltage 8.08 V or more at engine start.
        Battery Temperature -10°C to 70°C (50°F to 158°F)*1
        Battery Integrated Current*2

        When the integrated current value meets any of the following conditions:


        • -15444 A-sec or more: Status of battery charge control is charge control coordination mode, stop and start standalone mode or low temperature mode (3°C (37.4°F) to 10°C (50°F))*3.

        • -4554 A-sec or more: When status of battery charge control is low temperature mode (-1°C (30.2°F) to 3°C (37.4°F).*4

        • 0 A-sec or more: Status of battery charge control is stop and start restriction mode or temperature high/low mode.*5
        Air Conditioning The cooling, heating and defrost functions are not operating.
        ECU Learning Completed
        Ambient Temperature -5°C (23°F) or more
        Steering Operation Not operated

        *1: When the battery temperature becomes 75°C or higher, control is prohibited. After control is prohibited and the battery temperature falls to 70°C or lower, control is performed.

        *2: Regarding Battery Integrated Current

        In the stop and start system, the engine stop and start ECU switches the system control mode (stop and start system control permitted/prohibited) based on the battery condition (charge/discharge condition) to protect the battery and to ensure stable engine restarting performance.

        The battery charge-discharge condition is determined from the integrated current value calculated from the battery sensor (battery state sensor assembly) signal. The integrated current value is obtained by multiplying the current (ampere) detected by the battery sensor (battery state sensor assembly) by the time (seconds), and is expressed in the unit A-sec. This can be measured by the Global TechStream (GTS).

        The engine stop and start ECU determines the power charge based on the integrated current value and prohibits stop and start system control if the value is below the threshold, because the battery might not be able to start the engine. The threshold varies according to the battery temperature and battery charge condition.

        *3: After the integrated current value becomes -16434 A-sec or less, in order to charge the battery, control is prohibited until the value becomes -15444 A-sec or more.

        *4: After the integrated current value becomes -5544 A-sec or less, in order to charge the battery, control is prohibited until the value becomes -4554 A-sec or more.

        *5: After the integrated current value becomes 0 A-sec or less, in order to charge the battery, control is prohibited until the value becomes -990 A-sec or more.

      2. The engine will restart if any of these conditions are detected.

        Item Operating Condition
        Engine Restart Brake Booster Vacuum Insufficient brake booster vacuum
        Air Conditioning When the air conditioning is on and a timer in the air conditioning amplifier assembly completes.
        When the automatic blower function is operating and a timer in the air conditioning amplifier assembly completes. Otherwise, a timer in the engine stop and start ECU completes.
        The A/C switch, blower switch, rear window defogger switch or mirror heater switch is turned on.
        Evaporator temperature exceeds threshold (threshold varies with temperature, humidity and amount of solar radiator)
        Stop and Start Cancel Switch The stop and start cancel switch is turned on.
        Battery The battery voltage is less than 11.4 V.
        The battery integrated current drops to below the threshold value.
        Driver's Door The driver's door is opened.
        Driver's Seat Belt The driver's seat belt is unfastened.
        Vehicle Speed A vehicle speed signal is input.
        Accelerator Pedal The accelerator pedal is depressed.
        Brake Pedal The brake pedal is released.*1
        Shift Lever The shift lever is moved from D to other position.
        Steering Operation The steering wheel is operated.
        Engine Hood The engine hood is opened.*2

        *1: Only when the shift lever is in D.

        *2: Only when the shift lever is in P.

  3. FUNCTION


    1. Settings of Stop and Start System


      1. Using the stop and start cancel switch or steering pad switch on the steering pad switch assembly and the multi-information display on the combination meter assembly, the engine stop operation time due to stop and start control when the air conditioning system is on can be changed between Standard and Extended (the stop and start system has priority).

  4. DIAGNOSIS


    1. When the engine stop and start ECU detects a malfunction and CAN communication is normal, the engine stop and start ECU records information related to the malfunction. Furthermore, the stop and start indicator light in the combination meter assembly blinks to inform the driver that CAN communication is normal.

    2. The engine stop and start ECU also stores Diagnostic Trouble Codes (DTCs) related to malfunctions. DTCs can be read using the Global TechStream (GTS).