Active Hood Latch Apparatus Pedestrian Impact Absorption
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Solution Overview
Problem
In vehicle collisions with pedestrians, the existing active hood systems fail to effectively reduce secondary impacts due to the lack of a mechanism to absorb impact energy, leading to significant damage from the pedestrian's head colliding with the hood.
Innovation Solution
An active hood latch apparatus that includes a latch, a base panel, a lever member, a locking part, and a driving part, which, upon collision, rotates the lever member to raise the striker and absorb impact by moving the hood upward, utilizing an explosion-driven power transmission system to restrain the lever member from returning and ensure the hood remains closed post-collision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the hood is designed with a strong structure to shield the engine room, then the engine room protection is improved, but the pedestrian safety deteriorates due to increased secondary impact
Solution Approach 1:
The hood latch apparatus transitions from a static locked state to a dynamic unlocked state upon collision detection. The lever member rotates from an initial position to a second position, actively changing the hood's constraint state to absorb impact energy and reduce secondary impact on pedestrians.
Solution Approach 2:
The system converts the harmful collision force into a beneficial unlocking action. When the collision force acts on the lever member, it automatically triggers the latch release mechanism, transforming the harmful impact into the useful function of hood opening to protect pedestrians.
2Reliability
If the lever member is made rotatable to raise the striker, then the impact absorption capability is improved, but the device complexity increases due to additional locking and restraint mechanisms
Solution Approach 1:
Multiple functions are merged into a single integrated latch apparatus. The locking part, restraint mechanism, lever member, and driving part work together as one unified system, reducing overall complexity compared to separate systems while maintaining reliable impact absorption.
Solution Approach 2:
The latch mechanism is designed to automatically lock and unlock based on collision forces without external control. The restraint part and locking part self-activate when the lever member rotates, eliminating the need for external actuators or complex control systems.
3Reliability
If the locking part restrains the lever member after striker release, then the hood closure reliability is improved, but the ease of operation deteriorates due to restricted lever member movement
Solution Approach 1:
The locking part is positioned to preemptively restrain the lever member before any unintended movement can occur. This preliminary constraint ensures the hood remains securely closed during normal operation while automatically allowing movement when collision forces are applied.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The apparatus reduces secondary impacts on pedestrians by creating a shock absorption space between the engine room and the hood, ensuring the hood remains closed to prevent noise, vibration, and foreign substances from entering the vehicle during movement.
Implementation Method 1
a driving part rotating the lever member by a force larger than a restraint force of the locking part that restrain the guide pin, to supply power to raise the striker
Data Source
AI summary
An active hood latch apparatus for a vehicle includes a latch for locking or unlocking a striker connected to a hood; a base panel installed such that the latch can be rotated; a lever member rotatably installed in the base panel, the striker locked by the latch being located in a rotational path thereof; a locking part rotatably installed in the base panel to restrain movement of a guide pin, and to release the restraint of the guide pin in conjunction with the rotation of the lever member; and a driving part rotating the lever member by a force larger than a restraint force of the locking part that restrain the guide pin, to supply power to raise the striker, and then absorbing an impact.