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 due to a collision.
OUTLINE OF PRE-CRASH SAFETY SYSTEM |
Operating Condition | Control | Transmitting ECU | Receiving ECU | Part Operated |
Operates according to sensor detection | Pre-crash seat belt | Driving support ECU | Seat belt control ECU | Front seat outer belts |
Operates according to sensor detection | Pre-crash brake assist | Driving support ECU | Brake booster with master cylinder (skid control ECU) | Brake assist system |
Operates when sudden braking occurs | Pre-crash seat belt | Brake booster with master cylinder (skid control ECU) | Seat belt control ECU | Front seat outer belts |
Operates according to sensor detection | Pre-crash brake | Driving support ECU | Brake booster with master cylinder (Skid control ECU) | Brake system |
When operating according to sensor detection:
The millimeter wave radar sensor detects vehicles and other objects on the road in front of the user's vehicle. The driving support ECU determines if a collision is unavoidable based on object position, speed and track information. If the driving support ECU determines that a collision is unavoidable, it transmits this information to the following areas using CAN communication:
When operating as a result of sudden braking:
The brake booster with master cylinder (skid control ECU) uses brake pressure information and other data to determine if the driver has suddenly applied the brakes. If so, the brake booster with master cylinder (skid control ECU) sends a signal to the seat belt control ECU through CAN communication and the pre-crash seat belts activate.
OUTLINE OF PRE-CRASH SEAT BELT CONTROL |
The pre-crash seat belts operate depending on what the sensor detects, or whether 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 CONTROL |
The pre-crash brake assist 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 the rate of deceleration.
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 driving support 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 driving support ECU determines that a collision is unavoidable:
Brake fluid pressure is increased at the same time that the driving support ECU receives a pre-crash sensor signal (indicating that other vehicles or objects are in front of the vehicle).
OUTLINE OF PRE-CRASH BRAKE CONTROL |
The pre-crash brake operates depending on what the sensor detects. This system can be canceled by the satellite switch (pre-crash brake cancel switch).
Operative condition
Refer to the sensor description under "Outline of Pre-Crash Safety System" (see above).
When the driving support ECU determines that a crash is unavoidable, the system performs brake control to reduce the vehicle speed.
OPERATIVE CONDITION AND INOPERATIVE CONDITION OF EACH CONTROL (REVIEW) |
Pre-Crash Seat Belt*1 | Pre-Crash Seat Belt*2 | Pre-Crash Brake Assist*2 | Pre-Crash Brake*2*5 | |
Power switch off or on (ACC) | - | - | - | - |
When a warning message is displayed on the multi-information display | *3 | *3 | *3 | *3 |
When seat belt(s) is/are fastened | *4 | *4 | ○ | ○ |
Operates when the vehicle speed is 30 km/h (18 mph) or more, regardless of relative speed | ○ | - | - | - |
Operates when the vehicle speed is 5 km/h (3 mph) or more and relative speed is 30 km/h (18 mph) | - | ○ | - | - |
Operates when the vehicle speed is 15 km/h (9 mph) or more and relative speed is 15 km/h (9 mph) | - | - | - | ○ |
Operates when the vehicle speed is 30 km/h (18 mph) or more and relative speed is 30 km/h (18 mph) | - | - | ○ | - |
When the vehicle collides with an object outside the detection range of the millimeter wave radar sensor (side crash, rear crash, etc.) | ○ | - | - | - |
When the millimeter wave radar sensor cannot detect a possible crash object | ○ | - | - | - |
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 driving support ECU may determine that a collision is unavoidable, and activate the pre-crash safety system. This activation of the system is not abnormal.
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, etc. |