Pre-Crash Safety System -- System Description |
| PRE-CRASH SAFETY SYSTEM |
The pre-crash safety system optimizes and activates occupant protection equipment (see below) to attempt to reduce damage from collisions.
Outline of pre-crash safety system: Operating Condition Control Transmitting ECU Receiving ECU Part operated Operates according to sensor detection Pre-crash seat belts Cruise control ECU assembly
(Distance control ECU)Seat belt control ECU Front seat outer belts Operates according to sensor detection Pre-crash brake assist Cruise control ECU assembly
(Distance control ECU)ABS & traction actuator assembly
(Skid control ECU)Brake assist system Operates according to sensor detection Damping force control Cruise control ECU assembly
(Distance control ECU)Suspension control ECU Shock absorbers Operates when sudden braking occurs Pre-crash seat belts ABS & traction actuator assembly
(Skid control ECU)Seat belt control ECU Front seat outer belts When operating according to sensor detection:
The per-crash sensor (millimeter wave radar sensor) detects vehicles and other objects on the road in front of the user's vehicle. The cruise control ECU assembly (distance control ECU) determines if a collision is unavoidable based on object position, speed and track information. if the cruise control ECU determines that a collision is unavoidable, it transmits this information to the following areas through CAN communication:- Seat belt control ECU (initiates control of pre-crash seat belts)
- ABS & traction actuator (skid control ECU) (activates pre-crash brake assist system)
- Suspension control ECU (tightens the suspension as much as possible)
- Seat belt control ECU (initiates control of pre-crash seat belts)
When operating as a result of sudden braking:
The ABS & traction actuator (skid control ECU) uses brake pressure information and other data to determine if the driver has suddenly applied the brakes. If so, the ABS & traction actuator sends a signal to the seat belt control ECU through CAN communication and the pre-crash seat belt activates.
| OUTLINE OF PRE-CRASH SEAT BELT CONTROL |
The pre-crash seat belt operates depending on what the sensor detects, or whether or not sudden braking has occurred. The pre-crash seat belt motor tightens the seat belt to optimize occupant restraint performance.
Operative condition
Refer to the sensor and sudden braking descriptions under "outline of pre-crash safety system" (see above).
| OUTLINE OF PRE-CRASH BRAKE ASSIST SYSTEM |
The pre-crash brake assist system operates depending on what the sensor detects. The system then enters standby mode before a collision. When the driver depresses the brake pedal, brake fluid pressure is increased to improve fluid pressure response and improve vehicle speed reduction rate.
Operative condition
Refer to the sensor description under "outline of pre-crash safety system" (see above).
When the driver depresses the brake pedal after the cruise control ECU assembly (distance control ECU) determines that a collision is unavoidable:
Brake fluid pressure is increased at the same time the driver depresses the brake pedal.When the driver depresses the brake pedal before the cruise control ECU assembly (distance control ECU) determines that a collision is unavoidable:
Brake fluid pressure is increased at the same time that the cruise control ECU assembly (distance control ECU) receives a pre-crash sensor signal (indicating that other vehicles or objects are in front of the vehicle).
| OPERATIVE CONDITION AND INOPERATIVE CONDITION OF EACH CONTROL (REVIEW) |
| Item | Pre-crash seat belts (*1) | Pre-crash seat belts (*2) | Pre-crash brake assist (*2) |
| Engine switch off or on (ACC) | - | - | - |
| When a warning message is displayed on the multi-information display | *4 | *4 | *4 |
| When seat belt(s) is / are fastened | *5 | *5 | ○ |
| Operates when own vehicle speed is 30 km/h or more, regardless of relative speed | ○ | - | - |
| Operates when own vehicle speed is 5 km/h or more and relative speed is 30 km/h or more | - | ○ | ○ |
| When the vehicle collides with an object outside the detection range of the millimeter wave radar sensor (side collision, rear collision, etc.) | *6 | - | - |
| When the millimeter wave radar sensor cannot detect a possible collision object | *6 | - | - |
- HINT:
- *1: Operates when brakes are suddenly applied
- *2: Operates according to sensor detection
- *3: Fail-safe function (Click here)
- *4: Inoperative parts are different depending on malfunction areas
- *5: Only operates when seat belt is fastened
- *6: Pre-crash seat belts may operate when brakes are suddenly applied
| PRECAUTION FOR PRE-CRASH SAFETY SYSTEM OPERATION |
When the millimeter wave radar sensor detects an object in front of the vehicle under the conditions described below, the cruise control ECU assembly (distance control ECU) may determine that a collision is unavoidable, and activate the pre-crash safety system. However, this is not abnormal.
- HINT:
- The pre-crash safety system will not activate when the pre-crash sensor detects safety cones and other plastic objects.
- The pre-crash safety system may or may not activate when the pre-crash sensor detects the following objects: people, bicycles, motorcycles, trees, animals and snow fences.
Object Type Example Objects that cannot be detected Plastic items (safety cones) Objects that cannot be detected in a stable manner People, bicycles, motorcycles, trees, animals, snow fences