Deployable Hood Latch for Pedestrian Protection
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Solution Overview
Problem
Existing hood latch systems in motor vehicles are complex, costly, and obstruct airflow and cooling, while also failing to adequately absorb impact forces during pedestrian collisions, leading to severe head injuries due to limited hood deflection.
Innovation Solution
A low-cost, add-on hood latch deployment module that uses a sensing device, such as radar, to detect pedestrians and activate a solenoid to release a torsion spring, raising the hood to increase deflection and absorb impact energy, thereby reducing the force on a pedestrian's head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a traditional latch assembly is used, then the hood remains securely closed, but the pedestrian's head impacts the rigid hood with limited deflection, causing severe injuries
Solution Approach 1:
The system performs preliminary action by detecting the pedestrian's presence and position in advance of the collision, then pre-activating the hood latch release mechanism and positioning the hood in a partially open state before impact occurs. This allows the hood to be in a more compliant state during pedestrian contact, increasing deflection and reducing impact forces on the pedestrian's head.
Solution Approach 2:
The system transforms the static hood latch into a dynamic system that can change its state based on real-time conditions. The hood latch is normally engaged to keep the hood closed, but can be released and repositioned to a partially open state upon detecting a pedestrian, allowing the hood to have variable rigidity and deflection characteristics depending on the situation.
2Object-affected harmful factors
If the hood is made more compliant to increase deflection, then pedestrian injuries are reduced, but the hood cannot effectively restrain engine components and may interfere with normal operation
Solution Approach 1:
The hood latch system transitions from a static locked state to a dynamic, conditionally variable state. Normally, the hood is securely latched to maintain engine compartment integrity and proper hood function. When a pedestrian is detected in the impact zone, the system releases the latch and positions the hood partially open, allowing increased deflection during pedestrian contact while maintaining normal hood function during ordinary operation.
Solution Approach 2:
The system changes the physical state and position parameters of the hood latch mechanism based on detected conditions. The latch transitions between engaged and disengaged states, and the hood position changes from fully closed to partially open, thereby altering the mechanical properties and deflection characteristics of the hood system in response to pedestrian presence.
3Object-affected harmful factors
If a complex deployment module is added to enable pedestrian-responsive hood release, then pedestrian safety is improved, but device complexity, manufacturing cost, and repair difficulty increase
Solution Approach 1:
The system integrates multiple functions into a single deployment module: pedestrian detection via radar, signal processing, latch release actuation, and hood positioning are combined in one integrated unit. This multi-functional approach reduces the need for separate components and systems, thereby managing complexity despite the advanced capabilities required for pedestrian safety.
Solution Approach 2:
The deployment module serves as an intermediary between the radar detection system and the hood latch mechanism. It receives signals from the radar, processes the information, and actuates the latch release through a solenoid or motor, thereby mediating between the sensing system and the mechanical hood release system in a coordinated manner.
4Measurement precision
If a radar-based sensing system is integrated, then pedestrian detection accuracy is improved, but manufacturing cost and system complexity increase
Solution Approach 1:
The radar system is integrated to serve multiple functions: pedestrian detection, pedestrian positioning, collision risk assessment, and trigger signal generation for the hood release. By using a single radar-based sensing system for multiple purposes, the patent reduces the need for separate sensing components, thereby managing manufacturing cost while maintaining high detection accuracy.
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 module effectively reduces pedestrian head trauma by allowing greater hood deflection and energy absorption, lowering deceleration levels and minimizing severe injuries during collisions.
Implementation Method 1
uses a sensing device, such as radar, to detect pedestrians
Implementation Method 2
activate a solenoid to release a torsion spring
Implementation Method 3
release a torsion spring, raising the hood to increase deflection and absorb impact energy
Data Source
AI summary
A motor vehicle hood latch mechanism for engaging a striker of a hood having a closed locked position and a released position is disclosed. The mechanism includes a latch assembly attached to a chassis member. The latch assembly includes a latch having a locking cam and a pawl movable between a locked position engaging the locking cam and an unlocked position away from the locking cam. A sensor detects the presence of a pedestrian proximate the front of the motor vehicle and generates a signal in response thereto. A deployment spring having an energized position and a released position is retained in an energized position by a release mechanism responsive to the signal generated by the sensor, such that actuation of the release mechanism releases the resilient member and rotates the pawl to the unlocked position to release the latch.