Lower Front Shield Convergent With EPP Insert for Pedestrian Impact
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Solution Overview
Problem
The existing lower convergent front shields in vehicles are heavy, which affects their aerodynamic performance and energy efficiency, while also failing to meet the regulatory requirements for pedestrian impact protection, particularly in tests using the Flex-PLI impactor.
Innovation Solution
A lower convergent front shield assembly incorporating an insert with a perforated structure made of expanded polymer material, such as expanded polypropylene, which is overmolded to form a solid part that provides the necessary stiffness and aerodynamic benefits, reducing the overall mass while maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single-piece injected plastic convergent is used to provide stiffness for pedestrian protection, then the stiffness and protection capability are improved, but the weight increases significantly (mass greater than 1.8 kg)
Solution Approach 1:
The patent applies composite materials by combining a rigid injected plastic frame structure with an expanded polymer material (such as expanded polypropylene or EPP) filling. This composite construction allows the convergent to maintain high stiffness for pedestrian protection while significantly reducing weight compared to solid injected plastic parts. The expanded polymer provides structural support and energy absorption characteristics.
Solution Approach 2:
The patent utilizes porous materials by employing expanded polymer material with cellular structure as the filling within the convergent. This porous/expanded material provides sufficient stiffness and energy absorption for pedestrian impact protection while having much lower density than solid plastic, thereby reducing the overall weight of the component.
2Strength
If notches are added to the lower convergent to provide stiffness, then the protection capability is improved, but the aerodynamic performance deteriorates
Solution Approach 1:
The patent applies local quality by strategically positioning the expanded polymer material within specific regions of the convergent structure. This allows stiffness to be enhanced locally where needed for pedestrian protection (at the lower track area) while maintaining smooth external surfaces and proper aerodynamic contours elsewhere, thus avoiding the aerodynamic penalties associated with notches.
3Object-generated harmful factors
If a fairing is added to guide air flow, then the aerodynamic performance is improved, but the weight increases (additional 400+ grams)
Solution Approach 1:
The patent applies multi-functionality by designing the convergent structure to simultaneously provide aerodynamic guidance, pedestrian protection, and structural support without requiring separate dedicated components. The integrated design of the frame with expanded polymer filling creates a multi-functional element that replaces what would otherwise require multiple separate parts (including fairings), thereby reducing overall weight.
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 solution achieves a significant weight reduction of up to 50% compared to traditional designs while ensuring compliance with pedestrian impact test criteria and maintaining aerodynamic performance, thus enhancing the vehicle's energy efficiency and safety.
Implementation Method 1
an expanded polymer material forming a solid part of said convergent
Data Source
Figure 1A~1B
Figure 2
Figure 3~4
AI summary
Lower convergent (A, 1) of a front shield assembly of a motor vehicle, comprising an insert (10) with an openwork structure and an expanded polymer material (2) forming a solid part of said convergent, said insert being at least partially integrated into said expanded polymer material.