Ford Fusion: Collision Warning and Collision Avoidance System / Collision Warning and Collision Avoidance System - System Operation and Component Description. Description and Operation

System Operation

System Diagram

Network Message Chart

  Network Input Messages - ACM

  Network Input Messages - CCM

  Network Input Messages - HUD

  Network Input Messages - IPC

  Network Input Messages - IPMA

  Network Input Messages - ABS module

Pre-Collision Assist System Operation

The pre-collision assist system is an additional safety feature on vehicles equipped with adaptive cruise control. The system is active whether the adaptive cruise control system is on or off. If the system detects a vehicle, pedestrian or other object in the vehicle path of travel, the system provides three levels of functionality:

• Visual and audible alert
• Brake support
• Active braking

The system uses object detection information from the radar sensor integrated in the CCM and the forward-looking camera in the IPMA mounted in the interior rear view mirror. The CCM and the IPMA scan a designated area in front of the vehicle. Messages are sent between the CCM and the IPMA on dedicated CAN circuits, which determine whether an object, vehicle or pedestrian is in the path of travel, the approximate distance to the object and how fast the vehicle is approaching it.

When the vehicle approaches the object, the CCM sends a message to the HUD module on the HS-CAN2 to flash the red warning Light Emitting Diodes (LEDs). The CCM sends an alert message on the HS-CAN2 to the GWM, and then to the IPC on the HS-CAN3 to sound an audible alert and show a warning message in the message center display. The CCM also sends a message to the ABS module on the HS-CAN2 to pre-charge the brakes in order to prepare them for rapid braking by the driver. If the system determines that a collision is imminent, an active braking message is sent from the CCM to the ABS module. The system will reduce the gap between the brake pads and discs, applying the brakes to slow vehicle speed without driver intervention. The vehicle will stop the vehicle to help the driver avoid a collision or reduce damage caused by the impact.

The pre-collision alert system uses image recognition software that can differentiate between shapes, which allows the system to determine if the approaching object is a vehicle or a pedestrian. If the camera does not recognize the shape as the rear end of a vehicle or a pedestrian, the system will not provide full function. The system may not work properly at night, in direct or low sunlight, when camera vision is reduced due to weather conditions or due to a blocked CCM radar sensor. If the IPMA camera module is obstructed, the pre-collision system will not respond properly to pedestrians or stationary vehicles, and reduces the ability to recognize moving vehicles. Unconventional vehicle types, pedestrians in groups or with complex backgrounds, or partly obscured pedestrians also may not be properly detected by the system.

The pre-collision assist system is active at speeds above 5 km/h (3 mph) and pedestrian detection is active at speeds up to 80 km/h (50 mph).

The pre-collision assist system has three levels of sensitivity detection (HIGH, NORMAL and LOW) that can be changed through the message center display in the IPC. The alert sensitivity can be adjusted and active braking can be turned OFF in the IPC. The active braking function will revert back to ON at the next ignition cycle.

When a system fault is detected with the pre-collision assist system, the message PRE-COLLISION ASSIST NOT AVAILABLE, PRE-COLLISION ASSIST NOT AVAILABLE SENSOR BLOCKED, or PRE-COLLISION ASSIST MALFUNCTION is displayed in the IPC message center.

Component Description

CCM

The CCM contains a radar sensor unit that determines the distance and relative speed of the vehicle that is in the path of travel.

HUD

The HUD contains the red Light Emitting Diodes (LEDs) that warn the driver of a possible collision event when commanded by the CCM.

There are certain situations when the warning Light Emitting Diodes (LEDs) cannot be seen, such as strong sunlight or when wearing sunglasses. The HUD module has a temperature sensor circuit that is integral to the module that senses the temperature of the Light Emitting Diodes (LEDs) internal to the module. When a high passenger compartment temperature such as strong sunlight is sensed by the temperature sensor, the warning Light Emitting Diodes (LEDs) can be temporarily disengaged. If this occurs, only the audible warning chime is used.

Warnings may not appear if there is little distance to the vehicle ahead or abrupt steering wheel and pedal movements are made.

IPMA

The IPMA is integral to the interior rear view mirror. The IPMA contains a forward-looking camera with a designated line of sight in front of the moving vehicle. The camera can detect and differentiate between an approaching object, vehicle or pedestrian in the path of travel. This information is shared with the CCM on dedicated CAN circuits.