Pre-Crash Safety System System Description

  1. PRE-CRASH SAFETY SYSTEM DESCRIPTION

  1. PRE-CRASH DETECTION OUTLINE

  1. PRE-CRASH SAFETY SYSTEM CONTROL DESCRIPTION

  1. PRE-CRASH ALARM CONTROL

  1. PRE-CRASH SEAT BELT CONTROL

  1. PRE-CRASH BRAKE ASSIST CONTROL

  1. PRE-CRASH BRAKE CONTROL

  1. AIR SUSPENSION CONTROL

  1. PRE-CRASH BRAKE CANCEL SWITCH ASSEMBLY

  1. PRE-CRASH SAFETY SYSTEM OPERATING CONDITION

  1. PRECAUTION FOR MILLIMETER WAVE RADAR SENSOR ASSEMBLY

Pre-Crash Safety System -- System Description



PRE-CRASH SAFETY SYSTEM DESCRIPTION
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.

PRE-CRASH DETECTION OUTLINE

  1. Front crash detection
    The driving support ECU receives information about vehicles and obstacles in front of the vehicle from the millimeter wave radar sensor. Then, based on the 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. Sudden braking detection
    The skid control ECU activates the pre-crash seat belts when it detects sudden braking. Sudden braking is determined based on brake fluid pressure and other information from the master cylinder pressure sensor.

  3. Vehicle control impossible judgment
    The pre-crash seat belts are activated when it is determined that there is a high probability that the vehicle cannot be controlled. The judgment is based on vehicle stability information from the yaw rate sensor and steering angle sensor.


PRE-CRASH SAFETY SYSTEM CONTROL DESCRIPTION

Operation Condition
Control
Sender ECU
Receiver ECU
Part Operated
Front crash detected
  1. Crash is possible
  2. Crash is unavoidable
Pre-crash alarm
Driving support ECU
Combination meter assembly
Combination meter assembly
Skid control ECU
Skid control buzzer
Crash is unavoidable
Pre-crash seat belts
Driving support ECU
Seat belt control ECU
Front seat outer belts
  1. Crash is possible
  2. Crash is unavoidable
Pre-crash brake assist
Driving support ECU
Skid control ECU
Brake assist system
Crash is unavoidable
Pre-crash brake
  1. Crash is possible
  2. Crash is unavoidable
Air suspension control*
Driving support ECU
Suspension Control ECU
Shock absorber
Sudden braking detected
Pre-crash seat belts
Skid control ECU
Seat belt control ECU
Front seat outer belts
Vehicle control impossible judgment
  1. *: w/ AVS

PRE-CRASH ALARM CONTROL
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.

PRE-CRASH SEAT BELT CONTROL
If the pre-crash sensor detects that a collision is unavoidable, the pre-crash safety system retracts the seat belt, thus enhancing the effectiveness of the seat belt pretensioner in a crash. The same happens if the driver makes an emergency braking or loses control of the vehicle.

PRE-CRASH BRAKE ASSIST CONTROL
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.

PRE-CRASH BRAKE CONTROL
When the system determines that a crash with an obstacle is unavoidable, the system performs brake control to reduce the vehicle speed.

AIR SUSPENSION CONTROL
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.

PRE-CRASH BRAKE CANCEL SWITCH ASSEMBLY
When the pre-crash brake cancel switch assembly in the No. 1 instrument panel under cover sub-assembly*1 or No. 2 instrument panel under cover sub-assembly*2 is turned on, the pre-crash alarm and pre-crash brake do not operate.
  1. *1: for LHD
  2. *2: for RHD
HINT:
While the pre-crash brake cancel switch assembly is on, the PCS indicator light in the combination meter assembly illuminates.

PRE-CRASH SAFETY SYSTEM OPERATING CONDITION

Vehicle Condition
Pre-crash Alarm
Pre-crash Seat Belt
(Linked with Understeer or Oversteer Tendency Operation and Sudden Brake Operation)
Pre-crash Seat Belt
(Linked with Radar)
Pre-crash Brake Assist
Pre-crash Brake Control
Air Suspension Control*3
Ignition switch is off or ACC
X
X
X
X
X
X
Pre-crash brake cancel switch assembly is on
X
○
○
○
X
○
Warning message is displayed on multi-information display
*1
*1
*1
*1
*1
*1
Seat belt(s) are fastened
○
○
○
○
○
○
Vehicle speed is 30 km/h (18 mph) or more, regardless of relative speed
X
○
X
X
X
X
Vehicle speed is 15 km/h (9 mph) or more and relative speed is 15 km/h (9 mph)
○
X
X
X
○
○
Vehicle speed is 5 km/h (3 mph) or more and relative speed is 30 km/h (18 mph)
X
X
○
○
X
○
Vehicle speed is 30 km/h (18 mph) or more and relative speed is 30 km/h (18 mph)
X
X
X
○
X
○
Vehicle collides with object outside detection range of millimeter wave radar sensor assembly
X
*2
X
X
X
X
Millimeter wave radar sensor assembly cannot detect possible collision object
X
*2
X
X
X
X
  1. ○: Operation
  2. X: No operation
  3. *1: Inoperative functions are different depending on malfunction areas
  4. *2: Pre-crash seat belts may operate when brakes are suddenly applied
  5. *3: w/ AVS

PRECAUTION FOR MILLIMETER WAVE RADAR SENSOR ASSEMBLY


  1. When the millimeter wave radar sensor assembly 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 activate the pre-crash safety system. However, this is not abnormal.


    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Pre-Crash Safety.Pre-Crash Safety System.Pre-Crash Safety System System Description

    HINT:
    1. The pre-crash safety system is not activated by safety cones and other plastic objects which cannot be detected by the millimeter wave radar sensor assembly.
    2. The pre-crash safety system may or may not be activated by the following objects which cannot always be detected by the millimeter wave radar sensor assembly: people, bicycles, motorcycles, trees, animals, snow fences, etc.

    Object Type
    		Example
    Object that cannot be detected
    		Safety cones, plastic items
    Object that cannot always be detected
    		People, bicycles, motorcycles, trees, animals, snow fences, etc.