PRE-CRASH SAFETY SYSTEM SYSTEM DESCRIPTION


  1. PRE-CRASH SAFETY SYSTEM DESCRIPTION


    1. The pre-crash safety system detects vehicles and obstacles in front of the vehicle and performs the following: 1) optimally uses system controls to avoid crashes, and 2) uses system controls to reduce impact during a crash.

  2. PRE-CRASH SAFETY DETECTION OUTLINE


    1. Front crash detection


      1. The driving support ECU receives information about vehicles and obstacles in front of the vehicle from the millimeter wave radar sensor assembly. Then, based on vehicle speed, road conditions and obstacle location, the driving support ECU determines, in advance, the risk of a crash and if a crash is unavoidable.

      2. The driver monitor camera detects the direction that the driver's head is facing and whether the driver's eyes are open or closed. When a potential crash is detected and the camera determines that the driver's head is not facing forward or that the driver's eyes are closed, it activates the pre-crash safety controls in advance.

    2. Sudden braking detection


      1. The skid control ECU assembly activates the pre-crash safety seat belts when it detects sudden braking. Sudden braking is determined based on brake oil pressure and other information from the master cylinder pressure sensor.

    3. Vehicle control impossible judgment


      1. The pre-crash safety seat belts are activated when it is determined that the vehicle cannot be controlled. The judgment is based on vehicle stability information from the yaw rate sensor and steering angle sensor.

    4. Component

      Component Detection Content
      Millimeter wave radar sensor assembly Front object
      Skid control ECU assembly Sudden braking or vehicle control is not possible
      Driver monitor camera*

      • Driver facial direction

      • Driver eye opening level signal

      • *: w/ Driver Monitor Camera

  3. PRE-CRASH SAFETY SYSTEM CONTROL DESCRIPTION

    Operation Condition Controls Sender ECU Receiver ECU Part Operated
    Front crash detection Crash is possible Pre-crash safety alarm Driving support ECU

    • Combination meter assembly

    • Skid control ECU assembly

    • Combination meter assembly

    • Skid control ECU assembly
    Crash is unavoidable Pre-crash safety seat belts Driving support ECU Seat belt control ECU Front seat outer belts

    • Crash is possible

    • Crash is unavoidable

    • Pre-crash safety brake assist

    • Pre-crash safety brake

    		 Driving support ECU Skid control ECU assembly Brake assist system

    • Crash is possible

    • Crash is unavoidable

    		 Suspension control Driving support ECU Absorber control ECU Shock absorber
    Crash is possible Variable gear ratio steering control Driving support ECU Front steering control ECU assembly Steering actuator
    Sudden braking detected Pre-crash safety seat belts Skid control ECU assembly Seat belt control ECU Front seat outer belts
    Vehicle control impossible judgment Pre-crash safety seat belts Skid control ECU assembly Seat belt control ECU Front seat outer belts

  4. PRE-CRASH SAFETY ALARM CONTROL


    1. When the system determines that there is a risk of colliding with an obstacle in front of the vehicle, the multi-information display and warning buzzer are used to warn the driver and help with crash avoidance.

  5. PRE-CRASH SAFETY SEAT BELT CONTROL


    1. When the system determines that a crash with an obstacle is unavoidable, that sudden braking has occurred, or that vehicle control is impossible, the system performs seat belt control. During seat belt control, slack in the seat belts is reduced to increase occupant restraint and aid the pretensioner.

  6. PRE-CRASH SAFETY 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 is set to standby mode. Then, when the driver depresses the brake pedal, the hydraulic brake pressure is increased to improve braking effectiveness.

  7. SUSPENSION CONTROL


    1. When it is determined that there is a risk of colliding with an obstacle in front of the vehicle, the AVS is operated to control the damping force, suppress nose diving and rolling, and support collision avoidance through steering.

  8. VARIABLE GEAR RATIO STEERING CONTROL


    1. When the system determines that there is a risk of colliding with an obstacle in front of the vehicle, the Variable Gear Ratio Steering (VGRS) system is set to standby at an optimum steering ratio (i.e., increasing power steering) for collision avoidance.

  9. PRE-CRASH SAFETY BRAKE CONTROL


    1. When the system determines that a crash with an obstacle is unavoidable, the system performs brake control to reduce the vehicle speed. The pre-crash brake response time in cases when there is a vehicle in front has been increased. This results in less damage and injury.

  10. PRE-CRASH SYSTEM CANCEL SWITCH


    1. When the pre-crash system cancel switch assembly in the No. 1 instrument panel under cover sub-assembly is turned on, the pre-crash safety does not operate.

      Tech Tips

      While the pre-crash safety system cancel switch is ON, the combination meter's PCS indicator light blinks.

  11. PRE-CRASH SAFETY SYSTEM OPERATING CONDITION

    Vehicle Condition Pre-crash Safety Alarm

    Pre-crash Safety Seat Belt

    (Sudden braking or vehicle control is not possible)

    Pre-crash Safety Seat Belt

    (Avoiding collision is not possible)

    		 Pre-crash Safety Brake Assist Pre-crash Safety Brake Suspension Control Variable Gear Ratio Steering Control
    Power switch off or on (ACC) X X X X X X X
    When warning message is displayed on multi-information display *1 *1 *1 *1 *1 *1 *1
    When seat belt(s) are fastened ○ *2 *2 ○ ○ ○ ○
    When own vehicle speed is 15 km/h (10 mph) or more, regardless of relative speed X ○ X X X X X
    When own vehicle speed is 15km/h (10 mph) or more and relative speed is 15 km/h (10 mph) X X X X ○ X X
    When own vehicle speed is 5 km/h (4 mph) or more and relative speed is 30 km/h (19 mph) X X ○ X X ○ ○
    When own vehicle speed is 30 km/h (19 mph) or above, and relative speed of other vehicle is 30 km/h (19 mph) or above X X X ○ X X X
    When vehicle collides with object outside detection range of front millimeter wave radar sensor (side collision, etc.) X *3 X X X X X
    When front millimeter wave radar sensor cannot detect possible collision object X *3 X X X X X
    When pre-crash system cancel switch ON X X X X X X X

    Tech Tips


    • ○: Operation

    • X: Not operation

    • *1: Inoperative parts are different depending on malfunction areas

    • *2: Only operates when seat belt is fastened

    • *3: Pre-crash safety seat belts may operate

  12. PRECAUTION FOR MILLIMETER WAVE RADAR SENSOR


    1. When the millimeter wave radar sensor detects an object in front of the vehicle under the conditions described below, the driving support ECU may determine that a collision is unavoidable, and activates the pre-crash safety system. However, this is not abnormal.

      A01FV3BE01
      Text in Illustration
      *a There are objects on the side of the road at the beginning of a curve (a guardrail, street lamp, billboard, etc.). *b Passing an oncoming vehicle on a curve.
      *c There is an oncoming vehicle when making a right turn. *d Crossing a narrow metal bridge.
      *e There are metal objects on the road. *f Approaching leading vehicle suddenly.
      *g Electrical Toll Collection gate. (React to bar.) *h Crossing an overpass, traffic sign, signboard
      *i The vehicle height drastically changes (nose-up, nosedown). *j Misalignment of millimeter wave rader occurs. (reinstall, collision, etc)
      *k There are metal objects at the bottom of a decline (a metal plate covering road construction, a mesh drain cover, a manhole, etc.) *l There is a billboard or sign at the top of an incline.
      *m Roughness on road surface. - -

      Tech Tips


      • The pre-crash safety system does not activate when the pre-crash safety sensor detects safety cones and other plastic objects.

      • The pre-crash safety system may or may not activate when the pre-crash safety sensor detects the following objects: people, bicycles, motorcycles, trees, animals and snow fences.

      Object Type Example
      Object that cannot be detected Plastic items (safety cones)
      Object that cannot always be detected People, bicycles, motorcycles, trees, animals, snow fences, etc.