Vehicle Exhaust Flexible Boot for Thermal Stress Mitigation
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Solution Overview
Problem
Existing vehicle exhaust systems lack a flexible connection between the exhaust pipe and the exhaust finisher, which can lead to mechanical stress and noise due to thermal expansion and contraction, as well as movement from rough road conditions, resulting in a rigid and potentially damaging attachment.
Innovation Solution
A flexible boot with a deformable portion is attached to the rear end of the exhaust pipe and the forward end of the exhaust finisher, allowing for elastic deformation in response to thermal changes and movement, providing a sealed or non-sealed connection while accommodating thermal expansion and contraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid connection is used between the exhaust pipe and exhaust finisher, then structural strength is improved, but thermal expansion and contraction cause mechanical stress and noise
Solution Approach 1:
The patent applies a flexible boot (a flexible shell component) to connect the exhaust pipe to the exhaust finisher. This flexible boot allows thermal expansion and contraction of the exhaust pipe without transmitting mechanical stress to the exhaust finisher, thereby eliminating noise while maintaining connection integrity. The flexible shell absorbs dimensional changes through its elastic properties.
Solution Approach 2:
The patent changes the physical state of the connection from rigid to flexible by introducing a boot made of elastomeric material. This parameter change allows the connection to accommodate thermal expansion and contraction dynamically, preventing mechanical stress accumulation and noise generation while maintaining structural strength.
2Adaptability or versatility
If a flexible connection is used between the exhaust pipe and exhaust finisher, then thermal expansion and contraction are accommodated, but connection strength may be reduced
Solution Approach 1:
The flexible boot is constructed from composite or multi-layer elastomeric materials that provide both flexibility for thermal expansion accommodation and sufficient tensile strength for durable connection. The composite structure combines materials with different properties to achieve both adaptability and strength simultaneously.
Solution Approach 2:
The boot employs curved and flexible geometries rather than straight rigid connections, allowing it to bend and expand with thermal changes while maintaining structural integrity. The curved design distributes stress more evenly, preventing weak points and maintaining connection strength despite flexibility.
3Device complexity
If the exhaust pipe is directly attached to the exhaust finisher, then device complexity is reduced, but rough road conditions cause relative movement and mechanical stress
Solution Approach 1:
The flexible boot serves as an intermediate element between the exhaust pipe and exhaust finisher, absorbing relative movements caused by rough road conditions. This simple addition of a flexible shell component prevents mechanical stress without significantly increasing device complexity.
Solution Approach 2:
The boot acts as an intermediary element between the exhaust pipe and exhaust finisher, decoupling their relative movements. This mediator component absorbs shocks and vibrations from rough roads, preventing direct transmission of mechanical stress while maintaining a relatively simple overall structure.
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 flexible boot mitigates mechanical stress and noise by allowing the exhaust pipe to move relative to the exhaust finisher, ensuring a durable and quiet connection while maintaining a sealed or aerated interface, enhancing the vehicle's appearance by obscuring the underside view.
Implementation Method 1
The flexible portion is elastically deformable in response to thermal expansion and contraction of the exhaust assembly
Implementation Method 2
thermal expansion and contraction of the exhaust assembly
Data Source
AI summary
A vehicle exhaust system includes a vehicle body structure, an exhaust system, a rear bumper assembly, an exhaust finisher and a boot. The exhaust assembly is supported to an underside of the vehicle body structure. The rear bumper assembly is also supported to the vehicle body structure. The exhaust finisher is non-movably attached to one of the vehicle body structure and the rear bumper assembly. The exhaust finisher extends at least part way through an opening of the rear bumper assembly. The boot has a first end, a second end, and a flexible portion. The first end is attached to a rear end of the exhaust assembly. The second end is attached to a forward end of the exhaust finisher and the flexible portion extends from the trout end to the second end. The flexible portion is elastically deformable in response to thermal expansion and contraction of the exhaust assembly.