The design of a non-pyrotechnic active bonnet actuator to mitigate pedestrian head injury

Over the previous years, the requirements for future vehicle generations relating to pedestrian protection have been especially reviewed by automobile groups. These discussions brought forward new government regulations, which propose various testing methods which verify pedestrian protection on vehicles. In order for vehicles to comply with the head impact tests, the bonnet is required to have certain stiffness characteristics along with sufficient clearance between the bonnet and the engine components. However, if by design the vehicle has limited clearance optimal head protection can also be achieved by lifting the bonnet. This method consists of a sensory system which can identify a pedestrian impact, and an actuator system which can lift the bonnet into position during deployment. This project introduces a new active bonnet actuator, which is a fully resettable and reusable device which utilises a standard compression spring to store the energy required to lift the bonnet. The proposed design offers a simplified release mechanism compared to existing designs, which in addition offers a reduction in weight, and manufacturing cost whilst meeting current industry performance criteria. Finite Element will be used to verify the designs performance and insure structural integrity. While the new design is only verified through simulation, further testing and development would be required for the design to transition into usable product, this study does indicate that the new design has potential as an alternative lifting device for pedestrian protection.