Motor Vehicle Water Box Pedestrian Impact Energy Absorption
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Solution Overview
Problem
Conventional water boxes in motor vehicles do not effectively absorb the energy of pedestrian impacts, leading to potential cranial injuries due to their rigidity, and existing attempts at creating localized fragile zones fail to provide sufficient cushioning while maintaining necessary rigidity for normal vehicle operation.
Innovation Solution
A water box design featuring a central reinforcing beam and lateral elements with bending zones that allow for energy absorption during impacts, ensuring sufficient rigidity for normal operation and impact absorption, with the bending characteristics and positions optimized to meet safety criteria.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the water box is made rigid to ensure watertight sealing during normal operation, then sealing reliability is improved, but pedestrian safety deteriorates due to inability to absorb impact energy
Solution Approach 1:
The water box is designed with non-uniform wall thickness, featuring thinner front and lateral walls that can deform during impact while maintaining sufficient thickness in other areas for sealing reliability. This local variation in structural properties allows the box to be rigid where needed for sealing and flexible where needed for safety.
Solution Approach 2:
The invention changes the physical parameters of the water box by introducing specific thickness values (front wall 5-15mm, lateral walls 3-10mm) that are optimized to balance sealing requirements with impact energy absorption capabilities, allowing the structure to transition from rigid to deformable under impact conditions.
2Object-affected harmful factors
If localized fragile zones are added to break under impact, then the hard zone is erased, but the hood travel is extended and may hit another stiff part causing injury
Solution Approach 1:
The water box itself is designed to deform and absorb impact energy directly, converting the harmful rigid structure into a beneficial energy-absorbing element. This eliminates the need for separate fragile zones and prevents extended hood travel by providing progressive deformation throughout the water box structure.
3Object-affected harmful factors
If the water box height is increased to create free space for energy absorption, then impact energy absorption is improved, but the constrained environment near shock absorber cups limits the height
Solution Approach 1:
The water box employs localized thinning of wall thickness in specific areas (front and lateral walls) to create deformation zones that provide energy absorption capability without increasing the overall height of the water box, thus accommodating the constrained environment near shock absorber cups.
4Object-affected harmful factors
If an energy-absorbing material is used for the front edge, then impact energy is absorbed, but the front edge is not rigid enough to apply seal watertight during normal use
Solution Approach 1:
The invention optimizes the wall thickness parameter to a specific range (5-15mm for front wall, 3-10mm for lateral walls) that provides sufficient rigidity for sealing during normal operation while maintaining enough flexibility to deform and absorb impact energy during pedestrian collisions.
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 design effectively reduces pedestrian injury by absorbing impact energy through the bending of the reinforcing beam and lateral elements, meeting safety regulations and consumer test criteria while maintaining watertight sealing during normal vehicle use.
Implementation Method 1
the central element comprises a reinforcing beam extending over substantially its entire length under its front edge, said reinforcing beam being shaped to act in flexion under the effect of a pedestrian impact, the front edge of each lateral element comprises at least one bending zone shaped to allow bending of the front edge under the effect of a pedestrian impact
Data Source
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AI summary
The invention relates to a water reservoir (10) comprising: a central member (12) and two side members (14) positioned on either side of the central member (12) and rigidly secured thereto; and a substantially vertical front edge (16) extending along the length of the central (12) and lateral (14) members, oriented upwards transversely to the vehicle when the water reservoir (10) is mounted on the vehicle. According to the invention: the central member (12) comprises a reinforcement beam (122) extending along substantially the entire length of the member under the front edge (16) thereof and shaped to bend under the effect of a pedestrian impact, the front edge (16) of each side member (14) comprising at least one bending zone shaped to allow the front edge (16) to bend under the effect of a pedestrian impact. The invention also relates to a front structure equipped with such a water reservoir.