Cowl Cross Bar Assembly With Internal Stiffener for Crash Stiffness
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Solution Overview
Problem
The existing cowl cross bar assemblies in vehicles face challenges in reducing weight while maintaining sufficient stiffness to absorb collision energy effectively, particularly in electrical and eco-friendly vehicles where metallic materials are inadequate for improving fuel efficiency due to excessive weight and low extension rates of injection-molded compounds.
Innovation Solution
A cowl cross bar assembly design featuring hollow pipes with integrated stiffeners made of energy-absorbing materials like polypropylene or polyurethane, combined with a dash mounting member and stiffening plates, to absorb collision energy and enhance stiffness, while using lighter materials such as injection-molded compounds and carbon fiber for reduced weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metallic material such as steel is used for the cowl cross bar, then tensile strength and extension rate are improved, but weight increases excessively
Solution Approach 1:
The patent employs composite materials consisting of an injection-molded compound base material reinforced with fiber materials (such as glass fiber, carbon fiber, or aramid fiber). This composite structure provides tensile strength comparable to metallic materials while significantly reducing weight, thereby resolving the contradiction between strength and weight.
Solution Approach 2:
The patent applies fiber reinforcement selectively in regions requiring high strength, creating local quality enhancement. The fiber materials are embedded within the injection-molded compound to provide targeted structural support where needed, optimizing the strength-to-weight ratio.
2Weight of moving object
If injection-molded compound is used for the cowl cross bar, then weight is reduced, but extension rate and collision energy absorption capability deteriorate
Solution Approach 1:
By combining injection-molded compound with fiber reinforcement, the material achieves both low weight and high extension rate. The fiber network within the composite structure enables the material to extend and absorb collision energy effectively while maintaining the weight advantages of injection-molded materials.
Solution Approach 2:
The patent modifies the material parameters by incorporating fiber reinforcement into the injection-molded compound, fundamentally changing the material's mechanical properties to achieve both low weight and high extension rate suitable for collision energy absorption.
3Weight of moving object
If fiber reinforced injection-molded compound is used, then weight is reduced and strength is improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges the fiber reinforcement process with the injection-molding process, allowing both operations to be performed in an integrated manufacturing system. This combination simplifies production by eliminating separate assembly steps and enables automated manufacturing of the composite structure.
Solution Approach 2:
The injection-molding process is enhanced to serve multiple functions: it not only forms the basic structure but also embeds the fiber reinforcement and creates the final composite component in a single operation, reducing manufacturing complexity despite the advanced material system.
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 proposed design achieves a balance of reduced weight and increased stiffness, effectively absorbing collision energy and protecting passengers, while also improving fuel efficiency by utilizing lighter materials without compromising structural integrity.
Implementation Method 1
a stiffener accommodated in an internal space of the dash mounting member and configured to absorb collision energy generated in a collision of a vehicle
Implementation Method 2
A stiffening plate formed of metallic material may be coupled to some surfaces of the dash mounting member
Data Source
AI summary
A cowl cross bar assembly with a reduced weight and an increased stiffness. The cowl cross bar assembly includes a first pipe and a second pipe that are hollow and disposed laterally inside a chassis, a dash mounting member disposed between both ends of the first pipe, and a stiffener accommodated in an internal space of the dash mounting member and configured to absorb collision energy generated in a collision of a vehicle.