Active Hood Hinge Assembly for Expanded Pedestrian Cushion Space
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Solution Overview
Problem
Modern motor vehicles with low profile hoods and smaller engine compartments present a challenge for pedestrian protection systems, as they limit the available crush space, necessitating an improvement in active hinges to provide an expanded pedestrian cushion zone during collisions while maintaining normal hood operation.
Innovation Solution
An active hinge design featuring a body bracket, hood bracket, and deploy bracket connected by multi-bar linkage assemblies, with an actuator and release latching wire, allowing for unrestricted rotation during collisions to create an expanded cushion space while preserving normal hood operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If low profile hoods and smaller engine compartments are used to improve aesthetics and aerodynamics, then vehicle appearance and fuel efficiency are improved, but available crush space for pedestrian protection is reduced
Solution Approach 1:
The hood hinge assembly transitions from a static structure to a dynamic one that can change its configuration. The hinge includes a rotatable hood bracket that can pivot between a first position (normal operation) and a second position (deployed), allowing the system to adapt its geometry to provide crush space when needed while maintaining a low profile during normal use.
Solution Approach 2:
The invention utilizes rotational movement in a third dimension to create crush space. By rotating the hood bracket about a pivot point, the hood can be raised rearwardly to create vertical clearance, effectively using the vertical dimension to generate protection space without increasing the horizontal footprint of the engine compartment.
2Object-affected harmful factors
If active hinges with multiple linkages are used to provide expanded pedestrian cushion zone, then pedestrian protection is improved, but device complexity increases
Solution Approach 1:
The hood hinge assembly is divided into distinct functional components: a body bracket fixed to the vehicle body, a hood bracket attached to the hood, and a deploy bracket that can rotate relative to the hood bracket. This segmentation allows each component to perform its specific function while simplifying the overall design compared to traditional multi-linkage systems.
Solution Approach 2:
The deploy bracket serves multiple functions: it acts as a structural connector during normal hood operation and as a rotational mechanism for deploying the hood rearwardly during collision events. This multi-functionality reduces the need for separate components, thereby simplifying the overall hinge structure while maintaining protection capabilities.
3Object-affected harmful factors
If unrestricted rotation of hood bracket is allowed to create expanded cushion space, then pedestrian protection is improved, but normal hood operation is disrupted
Solution Approach 1:
The hinge assembly provides different rotational characteristics at different locations and under different conditions. During normal operation, the deploy bracket maintains a fixed angular relationship with the hood bracket, providing stable local geometry for normal hood function. During collision events, the deploy bracket can rotate freely to enable the hood to deploy rearwardly for pedestrian protection.
Solution Approach 2:
The system dynamically transitions between two operational states: a normal state where the deploy bracket is constrained to maintain proper hood alignment and operation, and a deployed state where the deploy bracket rotates freely to allow the hood to move rearwardly. This dynamic behavior ensures both normal operation and pedestrian protection are achieved without mutual interference.
Data Source
AI summary
An active hinge including a body bracket for attachment to a vehicle body. A hood bracket is provided for rotational attachment to a vehicle hood. An actuator is provided for selectively transitioning the active hood hinge from a normal mode where the rotation of the hood bracket is restricted, to an active pedestrian mode where the rotation of the hood bracket is unrestricted.