Pedestrian Protection Hood Hinge Assembly
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Solution Overview
Problem
Existing automotive hood hinge systems fail to provide adequate energy dissipation and structural restraint during pedestrian collisions, leading to potential head and chest trauma, and lack efficient mechanisms for latching, hinging, retaining, and resetting the hood in both rest and deployed positions.
Innovation Solution
A hood hinge assembly utilizing an energy storage actuator and series of linkages that constrain the hood's motion to a predetermined vertical path, providing a resistive force and structural restraint to dissipate pedestrian energy while allowing conventional opening and closing operations, and includes a reset mechanism for accidental deployments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a pyrotechnically powered actuator is used to extend the hinge arm in the guide track, then the hood can be raised to create a deformation path for energy dissipation, but there is no structural restraint to prevent the hood from being driven rearward through the windshield during substantial frontal impact
Solution Approach 1:
The patent employs a dynamic hinge assembly that transitions between two states: a retracted configuration for normal operation and a deployed configuration for pedestrian protection. The hinge arm can be positioned at different angles relative to the guide track, allowing the system to adapt its structural characteristics based on operational requirements. This dynamic reconfiguration enables the hood to provide both pedestrian safety and vehicle occupant protection.
Solution Approach 2:
The invention changes the geometric parameters of the hinge assembly by adjusting the hinge arm angle within the guide track. This parameter adjustment transforms the hood's structural behavior from a conventional fixed position to a deployed position with controlled vertical movement, creating the desired deformation path while maintaining structural integrity through the constrained motion path.
2Loss of energy
If material deformation is used to dissipate pedestrian impact energy, then energy dissipation occurs, but significant space beyond that available is required
Solution Approach 1:
Instead of using horizontal space for energy dissipation through material deformation, the invention utilizes the vertical dimension by raising the hood rearward. The guide track constrains the hinge arm to move primarily in the vertical direction, creating a compact energy dissipation mechanism that fits within the available vehicle structure without requiring significant additional space.
Solution Approach 2:
The system uses controlled dynamic movement of the hinge arm within the guide track to create vertical hood displacement. This dynamic approach allows energy dissipation through controlled deformation along a predetermined path, maximizing the use of available space while achieving the required 60-80 mm of vertical hood movement for effective energy attenuation.
3Reliability
If a multi-link hood hinge arrangement is used to guide the hood into deployed position and restrict rearward movement, then structural restraint is provided, but an additional actuator cylinder is required which adds significant cost and weight
Solution Approach 1:
The hinge assembly serves multiple functions: it acts as the primary hinge mechanism for normal hood operation, provides the deployment mechanism for pedestrian protection, and functions as the structural restraint system. The guide track and hinge arm combination performs all these roles without requiring separate actuators or complex resetting mechanisms, reducing overall system complexity and cost.
Solution Approach 2:
The invention merges the hinge function, deployment mechanism, and structural restraint into a single integrated assembly. The guide track and hinge arm work together to provide both the motion guidance for deployment and the structural constraint for rearward movement prevention, eliminating the need for separate multi-link arrangements and additional actuators.
4Ease of operation
If the hinge operates in a conventional manner with a single pivot, then conventional opening and closing operation is facilitated, but no controlled vertical motion path is provided for the rear edge of the hood during pedestrian collision
Solution Approach 1:
The hinge system is segmented into multiple functional components: a conventional single-pivot hinge for normal operation, a guide track for controlling vertical motion, and a hinge arm that connects both systems. This segmentation allows the hood to maintain simple conventional operation during normal use while providing controlled vertical motion through the guide track during pedestrian collision scenarios.
Solution Approach 2:
The hinge assembly is designed to perform dual functions: facilitating conventional hood opening and closing operations through the single pivot mechanism, and providing controlled vertical motion for energy dissipation during pedestrian impact. The same hinge components enable both operational modes without requiring separate systems.
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 system effectively reduces pedestrian trauma by controlling the hood's motion and providing a resistive force, preventing rearward movement during impacts and allowing for simple resetting, thus enhancing safety and operational efficiency.
Implementation Method 1
an energy storage actuator and series of linkages that constrain the hood's motion to a predetermined vertical path
Data Source
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AI summary
An automotive hood hinge assembly is adapted to act as a safety device in the event of a collision with a pedestrian. The hood hinge assembly is constructed from a series of linkages and an energy storage actuator that is configured to raise the rear of a vehicle hood in response to a pedestrian collision. The deployed system forms a rigid structure that restrains rearward movement of the hood while providing a vertical motion path and resistive force capable of efficiently dissipating the energy imparted by the pedestrian and therefore significantly lowering injury levels. The linkages are configured to provide conventional rotary opening and closing motion of the hood when the system is in the retracted position and also provide a reset function so that a simple opening and closing motion of the hood when the system is in the deployed position resets it to the retracted position.