PRE-CRASH SAFETY SYSTEM SYSTEM DESCRIPTION


  1. PRE-CRASH SAFETY SYSTEM DESCRIPTION


    1. The pre-crash safety system determines the possibility of a collision according to information such as the position of the obstacle and its relative speed, and provides optimal control to avoid the collision and control to reduce the impact during the collision via warnings, brake assist and automatic braking.

  2. FUNCTION OF COMPONENTS

    Component Function
    Pre-crash Safety City Sensor

    • Acquires information about the preceding vehicle from a monocular camera and laser radar to perform pre-crash safety system control.

    • Sends the information display, PCS warning light and PCS warning message signal to the combination meter assembly based on pre-crash control information.

    • Sounds the meter buzzer based on pre-crash safety system control information.
    Pre-crash System Cancel Switch Assembly Stops and starts the pre-crash safety system and changes the warning timing.
    Combination Meter Assembly

    • Displays the pre-crash safety system control status (ON/OFF) and warning timing.

    • During a system malfunction, warns the driver by displaying a message in the multi-information display according to the nature of the problem in the system, illuminating the PCS warning light and master warning light and sounding the meter buzzer.

    • Sounds the meter buzzer according to signals from the pre-crash safety city sensor.
    ECM

    • Detects the shift position signal and accelerator opening angle and sends that information to the pre-crash safety city sensor.

    • Performs engine output control based on information from the pre-crash safety city sensor.
    Brake Actuator Assembly (Skid Control ECU)

    • Sends information such as the vehicle speed signal, stop light switch signal and brake control hydraulic pressure to the pre-crash safety city sensor.

    • Performs brake hydraulic pressure and emergency brake signal control based on information from the pre-crash safety city sensor.
    Spiral with Sensor Cable Sub-assembly (Steering Angle Sensor) Detects the steering angle and steering direction.
    Yaw Rate Sensor Detects the steering angle and steering direction.
    Main Body ECU (Instrument Panel Junction Block Assembly) Sends destination information to the pre-crash safety city sensor.
    VSC OFF Switch Disables the pre-crash brake and pre-crash brake assist operation when the switch is turned on.

  3. OUTLINE OF PRE-CRASH DETECTION


    1. Collision detection


      1. The system determines in advance the possibility of a collision and whether the collision can be avoided based on road surface conditions and the position and speed of the preceding vehicle according to information about the preceding vehicle from the pre-crash safety city sensor.

        Tech Tips

        For details about the system, see "OUTLINE OF PRE-CRASH SAFETY SYSTEM CONTROL" and the function descriptions.

    2. Component

      Component Detection Content
      Pre-crash safety city sensor Obstacle in front (vehicle)

  4. OUTLINE OF PRE-CRASH SAFETY SYSTEM CONTROL

    Start of Control Control Condition Sender ECU Receiver ECU Operated Parts

    1. Collision is possible

    2. Collision is unavoidable

    		 Pre-crash warning Pre-crash safety city sensor Combination meter assembly

    • Combination meter assembly (warning display)

    • Meter buzzer (warning sound)
    Collision is highly possible Pre-crash brake assist Pre-crash safety city sensor Brake actuator assembly (skid control ECU)

    • Combination meter assembly (warning display)

    • Meter buzzer (warning sound)

    • Brake actuator assembly (skid control ECU)
    Collision is unavoidable Pre-crash brake Pre-crash safety city sensor

    • Combination meter assembly

    • Brake actuator assembly (skid control ECU)

    • ECM

    • Combination meter assembly (warning display)

    • Meter buzzer (warning sound)

    • Brake actuator assembly (skid control ECU)

  5. PRE-CRASH ALARM CONTROL


    1. When the system determines that there is a risk of colliding with an obstacle in front of the vehicle, a message on the multi-information display and the meter buzzer are used to warn the driver to avoid the collision.

  6. PRE-CRASH BRAKE ASSIST CONTROL


    1. When the system determines that there is a risk of colliding with an obstacle in front of the vehicle, brake assist enters standby status and the hydraulic brake pressure is increased to improve braking effectiveness when the driver depresses the brake pedal.

  7. PRE-CRASH BRAKE CONTROL


    1. When the system determines that a collision with an obstacle in front of the vehicle is unavoidable, the brakes are operated to reduce the collision speed and reduce the impact during the collision.

      Note

      When the system detects that the driver is attempting to cancel operation of the system by performing operations such as the following, pre-crash brake control is canceled.


      • Accelerator pedal is forcefully depressed

      • Steering wheel is operated quickly to avoid a collision

  8. VSC OFF SWITCH


    1. Turning the VSC OFF switch on disables pre-crash brake assist control and pre-crash brake control.

      Tech Tips

      After pressing the switch, the PCS warning light in the combination meter assembly illuminates and "PRE-CRASH BRAKE IS DISABLE DUE TO VSC OFF."*1 or "Pre-Crash Brake is disabled due to VSC OFF."*2 is displayed in the multi-information display.


      • *1: for Multi-information Display (Monochrome Type)

      • *2: for Multi-information Display (Color Type)

  9. PRE-CRASH SAFETY SYSTEM (PCS) OPERATION CONDITIONS


    1. Shared conditions:


      • Pre-crash safety system is on

      • VSC is not OFF

      • PCS warning light in the combination meter assembly is not blinking or illuminating

    2. Pre-crash warning operation conditions:


      • Vehicle speed is approximately 15 km/h (10 mph) or more and approximately 140 km/h (87 mph) or less

      • Relative speed of vehicle ahead is approximately 15 km/h (10 mph) or more

    3. Pre-crash brake assist control operation conditions:


      • Vehicle speed is approximately 30 km/h (19 mph) or more and approximately 80 km/h (50 mph) or less

      • Relative speed of vehicle ahead is approximately 30 km/h (19 mph) or more

    4. Pre-crash brake control operation conditions:


      • Vehicle speed is approximately 10 km/h (6 mph) or more and approximately 80 km/h (50 mph) or less

      • Relative speed of vehicle ahead is approximately 10 km/h (6 mph) or more

  10. OUTLINE OF PRE-CRASH SAFETY CITY HEATER (w/ Pre-crash Safety City Heater)


    1. Shared conditions:


      • Pre-crash safety system DTCs are not output

      • Engine running

    2. Operation conditions:


      • Ambient temperature 5 °C (41 °F) or less (air conditioning ambient temperature)

      • When the ambient temperature is between 5°C (41°F) and 20°C (68°F) and the glass in front of the pre-crash safety city sensor begins to fog up while driving (fogging detected in the pre-crash safety city sensor)

    3. Stop conditions:


      • Momentarily turns off every 30 minutes after operating the heater (determines whether the operation conditions are met again after turning off)

    4. Pre-crash brake control operation conditions:


      • Vehicle speed is approximately 10 km/h (6 mph) or more and approximately 80 km/h (50 mph) or less

      • Relative speed of vehicle ahead is approximately 10 km/h (6 mph) or more

  11. PRECAUTION FOR PRE-CRASH SAFETY CITY SENSOR


    1. When the following vehicle conditions are detected, the pre-crash safety city sensor determines that a collision is unavoidable and pre-crash control is performed, but this is not a malfunction.

      A004QPFE01
      Text in Illustration
      *A for RHD *B for LHD
      *a There are objects on the side of the road at the beginning of a curve (a guardrail, street light, billboard, etc.). *b Passing an oncoming vehicle on a curve.
      *c When passing an oncoming vehicle while making a left turn (for LHD) or right turn (for RHD). *d Passing through an area which contains an obstacle that covers the vehicle (such as a hanging curtain).
      *e There are metal objects, bumps and protrusions on the road (a metal plate covering road construction, a mesh drain cover, a manhole, etc.). *f Suddenly approaching a preceding vehicle.
      *g Approaching an electrical toll collection gate (reacts to bar). *h Crossing an overpass, traffic sign, signboard.
      *i The vehicle height drastically changes (nose-up, nose-down). *j Axis misalignment of pre-crash safety city sensor (reinstallation, collision, etc.).
      *k There is a billboard or sign at the top of an incline. *l There are metal objects at the bottom of a decline (a metal plate covering road construction, a mesh drain cover, a manhole, etc.).
      *m Snow, water, etc., is kicked up by the preceding vehicle. *n Passing through an area which contains heavy fog or smoke.
      *o The vehicle is stopped with the front extremely close to an obstacle (wall, vehicle, etc.). *p Passing extremely close to the side of an obstacle (stopped vehicle, guardrail, etc.).

      Tech Tips


      • The following table shows objects that the pre-crash safety city sensor cannot detect or has difficulty detecting reliably.

        Item Example
        Object not detected Plastic items (traffic cones, etc.)
        Object not detected reliably Humans, bicycles, motorcycles, trees, animals, snow walls, etc.

      • The detection performance of the monocular camera sensor may deteriorate under the following conditions.


        • The headlights are not illuminated when the surrounding area is dark, such as inside a tunnel or at night.

        • A strong light from directly ahead of the vehicle strikes the lens (light from the headlights of an oncoming vehicle, the sun, etc.).

        • The temperature of the sensor is extremely high, such as after the vehicle is parked in hot weather.

      • The following environments and vehicle conditions may cause the detection performance to deteriorate.


        • On a steep curve or undulating road.

        • Something or someone suddenly emerges in the direction of travel of the driver's vehicle at a place such as an intersection.

        • Another vehicle suddenly cuts in the traveling direction of the driver's own vehicle.

        • In severe weather such as heavy rain, fog, snow or a sand storm.

        • The vehicle is skidding sideways.

        • The vehicle height changes significantly (front of vehicle inclined either upward or downward).

        • The front windshield is dirty.

        • An obstacle is between the vehicle and a light source.

        • The preceding vehicle is one which does not easily reflect laser waves (the vehicle is low, small, dirty, etc.).

  12. PRE-CRASH SAFETY SYSTEM AUTOMATIC CANCELLATION


    1. When a system malfunction is detected and the sensor cannot detect vehicles, system operation cancels automatically.

      Tech Tips

      When the system malfunctions or is temporarily disabled, the PCS warning light will blink or illuminates.