GENERAL INFORMATION



AUTO STOP & GO (AS&G) SYSTEM


The purpose of the Auto Stop & Go (AS&G) system is to reduce CO2 exhaust gases from vehicles. The AS&G system automatically should stop the engine when the vehicle is stopped. And also the system should automatically restart the engine when the vehicle is started. The AS&G-ECU judges whether the engine should be stopped or restarted. The AS&G-ECU also stops or restarts the engine. The AS&G-ECU monitors the vehicle condition by using the signals from sensors and each ECU. If the specified conditions are satisfied, the AS&G-ECU should send the engine stop request signal to the engine-ECU via CAN. When receiving the signal, the engine-ECU should stop the engine (auto stop). When the driver depresses the brake pedal during the auto stop, the AS&G-ECU should turn on the starter relay and the starter cut relay to drive the starter, also should send the engine start request signal to the engine-ECU via CAN. When receiving the signal, the engine-ECU should restart the engine (auto start).
System Configuration Diagram


1. Auto Stop & Go (AS&G) System



When the ignition switch is turned "ON" or when the engine starts, the AS&G system should automatically be turned "ON". The driver can turn "OFF" the AS&G system by pressing the AS&G OFF switch. At that time, the AS&G OFF indicator/display should be turned "ON" in the combination meter. When the AS&G OFF switch is pressed again, the AS&G system should be turned "ON".

2. Auto Stop Control



The engine-ECU will stop the engine when the following operation is performed while the AS&G indicator/display illuminates.

  1. Depress the brake pedal when the vehicle is running to stop the vehicle. (D range transmission)
  2. If the brake pedal is depressed continuously when the vehicle has completely stopped, the engine will automatically stop.
During the auto stop, the AS&G indicator/display is turned "ON" in the combination meter. When one or more of following conditions are satisfied, the AS&G-ECU should prohibit the auto stop.

  • After the key is used to start the engine, approximately 30 seconds have not been taken.
  • The accelerator pedal is depressed.
  • If the vehicle is stopped again within approximately 10 seconds of the engine auto start.
  • More than the vehicle speed of approximately 5 km/h is not detected even once after the engine start, including the engine start of the auto start.
  • The vacuum pressure of the brake booster is less than specified value.
  • The brake fluid pressure is less than the specified value.
  • The driver’s seat belt is unfastened.
  • The hood is opened.
  • The driver’s door is opened.
  • The parking brakes are applied.
  • The steering wheel is being steered.
  • The vehicle slant angle is more than specified value.
  • The ambient temperature is lower than approximately 0°C.
  • The AS&G-ECU detects an abnormality in the AS&G system.
  • The auto stop prohibition signal is received from each ECU with the conditions described in the following table.
ECU
Auto stop prohibition condition
Engine-ECU

  • Not in idle operation
  • Engine coolant temperature: 50° or less
  • During the battery charging
  • Battery deterioration is detected
  • Battery temperature: 80° or less, -5° or more
  • The power steering motor current deviates from the specified value
  • The engine-ECU detects abnormality

CVT-ECU

  • CVT fluid temperature: 21° or less, 107° or more
  • Change gear ratio: Not in Low state
  • A speed of 5 km/h or more is never detected
  • 5 seconds have not passed after auto start
  • The CVT-ECU detects abnormality

ASC-ECU

  • The ASC-ECU detects abnormality

A/C-ECU

  • When the following are not set while the blower fan is "ON":

  1. Engine coolant temperature: Less than the specified temperature (changed by ambient temperature)
  2. Ambient temperature: Less than the specified temperature
  3. Room temperature: Outside the specified value range
  4. Evaporator temperature: More than the specified temperature (changed by ambient temperature)
  • The defroster mode is set
  • The temperature adjustment dial is set to the lowest or highest temperature


  • 3. Auto Start Control


    caution If the following motions are carried out during the auto stop even one time, the AS&G-ECU should blink the AS&G indicator/display in the combination meter and prohibits the auto start. Even if trying to return to the previous status after that, the auto start should be prohibited. When restarted, the engine must be started by the key.

    • In case the hood is opened
    • In case the driver’s seatbelt is unfastened and the driver seat door is open
    note When in the states mentioned above, the AS&G-ECU should send the signal to the combination meter via the CAN to sound the warning buzzer built into the combination meter. This warns the driver that this is different from normal use.

    Normal Auto Start


    Depending on the driver’s operation, the AS&G-ECU turns off the AS&G indicator/display that was displayed in the combination meter while quickly starting the engine. Auto start should function either by brake pedal or accelerator pedal operation. Auto start conditions are as follows:
    Selector lever
    Brake pedal
    Accelerator pedal
    P
    Released then depressed again
    Depressed
    R
    Auto start functions regardless of pedal state
    N
    Released
    Depressed
    D
    Released
    Depressed
    note If the selector lever is moved from D range to outside D range, and then back to D range again, the engine will the engine will perform auto start.

    Forcible Auto Start


    When one of the following conditions is satisfied during the auto stop, the AS&G-ECU should send the engine start request signal to the engine-ECU for starting the engine swiftly despite the driver’s determination. Also, the AS&G-ECU should turn on the starter relay to drive the starter. At that time, the AS&G indicator/display in the combination meter should go off as well as the normal auto start.

    • The vehicle speed is more than 3 km/h.
    • The steering wheel is being steered.
    • 3 minutes after Auto Stop state.
    • The vacuum pressure of the brake booster is less than specified value.
    • The AS&G-ECU detects an abnormality in the AS&G system.
    • The engine start request signal is received from each ECU with the conditions described in the following table. engine start request signal
    ECU
    Engine start request condition
    Engine-ECU

    • The battery’s charge state has deteriorated
    • Vehicle electrical load has increased
    • The engine-ECU detects abnormality

    CVT-ECU

    • The CVT-ECU detects abnormality

    ASC-ECU

    • The ASC-ECU detects abnormality

    A/C-ECU

    • A/C: "OFF" → "ON"
    • The defroster mode is set
    • The temperature adjustment dial is set to the lowest or highest temperature


    4. Control for Increasing Voltage


    At the auto start, the AS&G-ECU sends the increasing voltage request signal to the DC/DC converter. When receiving the signal, the DC/DC converter should temporarily switch the relay in the unit to the voltage converter of the DC/DC converter. The voltage converter increases the battery voltage dropping during cranking to 12.2 V. This can prevent the jumpy sound of the audio equipment due to the battery voltage drop at the auto start. The DC/DC converter should stop increasing the voltage when the input voltage returns to 12.2 V. There is a DC/DC converter in both the control system and the entertainment system. The control system controls the power supply voltage of the CVT-ECU and ASC-ECU. The entertainment system controls the power voltage supply of MMCS, audio, etc.

    5. AS&G System Indicator/Display Control



    The AS&G-ECU sends the signal to the combination meter via CAN, corresponding to the operation of the AS&G system. The combination meter that received the signal turns "ON" or blinks the indicator/display. Then the AS&G system status is informed to the driver.
    AS&G system
    Condition
    AS&G OFF indicator/display
    AS&G indicator/display
    OFF
    Ignition switch: ON (engine is stopped.); After several seconds are taken
    Illuminated/Displayed
    Extinguished/Not displayed
    During engine running
    Illuminated/Displayed
    Extinguished/Not displayed
    ON
    Ignition switch: ON (engine is stopped.); After several seconds are taken
    Extinguished/Not displayed
    Extinguished/Not displayed
    During idling and driving
    (The idling stop operation standby incomplete)
    Extinguished/Not displayed
    Extinguished/Not displayed
    During idling and driving
    (The idling stop operation standby complete)
    Extinguished/Not displayed
    Illuminated/Displayed
    During auto stop
    Extinguished/Not displayed
    Illuminated/Displayed
    Hood is opened
    Extinguished/Not displayed
    Blinked
    Driver’s door is opened
    Extinguished/Not displayed
    Blinked
    Driver’s seat belt is unfastened
    Extinguished/Not displayed
    Blinked
    During auto stop, selector lever is placed on "P" position and brake pedal is released
    Extinguished/Not displayed
    Blinked
    AS&G system is abnormal*
    Blinked
    Extinguished/Not displayed
    ON/OFF
    After ignition switch ON; for several seconds
    Illuminated/Displayed
    Illuminated/Displayed
    note *: The AS&G-ECU, engine-ECU, CVT-ECU or the ASC-ECU may detect a diagnosis code. Check whether the each ECU detects a diagnosis code or not.

    6. Starter Relay Control


    At Normal Engine Start
      When the following signals are input, the AS&G-ECU should turn "ON" the power transistor of the starter relay in the unit. This allows the starter relay to be turned "ON", and then the starter is driven. If the immobilizer result checking has some discrepancy, the output to the starter relay should be turned "OFF". The starter, therefore, should not be driven.

      • Ignition switch-ST signal
      • Transmission: "P" or "N" position
    At Engine Start from Auto Stop Status
      When detecting one of the following conditions during the auto stop, the AS&G-ECU should turn "ON" the power transistor of the starter relay in the unit. This allows the starter relay to be turned "ON", and then the starter is driven.