Principles Of Operation
The system is designed to help reduce head and lower leg injuries when a pedestrian has been hit by a vehicle. This is achieved in two main ways:
- Bumper design
- Pyrotechnic deployment of the hood.
The front bumper of the vehicle has been designed with a profile which encourages the pedestrians lower leg to lift upwards rolling around the front of the bumper surface. The bumper is constructed of energy absorbing foam and plastics and is designed to be softer around the top part of the bumper than the middle. This helps reduce injuries to the pedestrians lower leg.
As the pedestrians leg rolls around the bumper it deforms the bumper and the sensor beneath. If the predetermined parameters are met the Pedestrian Protection System control module fires the pyrotechnic hood latch pins which opens the hood latch claw. This is followed by the pyrotechnic actuator firing to force the hood upwards. As the hood moves upwards the secondary hood latch automatically engages with the secondary hood latch striker plate locking the hood and the body together via the tether cone attached to the hood actuator. This ensures that the hood only rises a set amount. The raising of the hood creates a more cushioned effect between the vehicle and the pedestrian. The hood actuators will deflate within 3 seconds of deployment to improve visibility. The secondary hood latch remains connected to the hood when the hood actuators have deflated and can be released by squeezing the two latch forks together, either by hand or with a pair of pliers.
The hazard warning lights will be activated and can only be switched off by pressing the engine Start/Stop button to turn the engine OFF and ON again (without pressing the brake pedal) to revert to the convenience mode.
A warning message CHECK PEDESTRIAN SYSTEM will appear on the message center and the vehicle must be immediately recovered to the nearest Jaguar Dealer/Authorized Repairer. The vehicle must not be driven once the bonnet has been deployed.
| Item Number | Description |
|---|---|
| 1 | Secondary hood latch |
| 2 | Secondary hood latch spring |
| 3 | Tether cone |
| 4 | Secondary hood latch retaining bracket |
| 5 | Electrical connector |
| 6 | Hood actuator |
| 7 | Secondary hood latch body |
| 8 | Secondary hood latch striker plate |
| Function | Value |
|---|---|
| Operating speed | 15-45 kph |
| Hood deployment height | 130mm |
| Hood deployment time (approx) | 30ms |