Pedestrian Impact Detection System Description and Operation

The pedestrian impact detection systems primary function is to provide supplemental protection to vulnerable road users involved in vehicle impacts. The pedestrian impact detection system is also known as the active pedestrian protection system. The pedestrian impact detection system is a functional system for raising the hood to provide sufficient vertical deformation space under the hood. In Europe and Japan an active pedestrian impact detection system is necessary for vehicles which do not provide the required deformation space under the hood. The pedestrian impact detection system includes the following components

• Pedestrian Impact Detection Module
• Discrimination Sensor (Front Upper Beam Sensor)
• Safing Sensor (Rear Upper Beam Sensor)
• Two Hood Hinge Actuators

The pedestrian impact detection system will sense and discriminate vulnerable road user impacts and deploy the hood hinge actuators in a timely manner to protect the pedestrian. The term "deployment" applies to the activation of the hood via the hood actuators. The pedestrian impact detection system is designed to sense and discriminate road user impacts (eg. pedestrian, cyclist) from other types of impacts in order to properly deploy the hood actuators. No actions or inputs are required from the driver or passenger to trigger this device. The pedestrian impact detection module uses the safing and discrimination sensor to get acceleration and force information needed for the deployment of the hood hinge actuators. The pedestrian impact detection module deploys the hood actuators using two deployment loops. The pedestrian impact detection system only operates at vehicles speeds between 27 km/h (16 mph) to 45 km/h (27 mph). The pedestrian impact detection module detects internal and interface faults and commands the Service Pedestrian Protection System message in the DIC to indicate a system fault.

After a deployment event, the vehicle operator is able to reset the hood to its normal driving position. After resetting the hood, the pedestrian impact detection system is not required to be fully functional. For full functionality, it is necessary to replace system component(s) at an approved service facility.