Multi-Layer Joint Insert for Exhaust Manifold Thermal Stress
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Solution Overview
Problem
Mechanical joints in internal combustion engines, such as those between the exhaust manifold and support bracket, experience wear and failure due to differential thermal growth, leading to stress and component degradation.
Innovation Solution
A multi-layer joint insert comprising a first and second metal sheet layer with fastener-receiving openings, joined by connecting arrangements that allow relative sliding movement, and optionally coated with anti-friction materials like molybdenum disulfide, to accommodate thermal expansion and reduce stress at the joints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid support bracket is used to support the exhaust manifold, then structural support is improved, but thermal growth stress and component failure increase
Solution Approach 1:
The joint insert is divided into multiple metal sheet layers (first layer, second layer, third layer) that can move independently relative to each other. This segmentation allows each layer to accommodate thermal growth differently, reducing stress concentration at the joint while maintaining overall structural support.
Solution Approach 2:
The connecting arrangements between metal sheet layers are designed to permit relative sliding movement, transforming the rigid joint into a dynamic structure that can adapt to thermal expansion. This dynamic capability allows the joint to absorb thermal growth stresses without causing component failure.
2Strength
If fasteners are used to join the exhaust manifold and support bracket, then mechanical connection is improved, but thermal stress and wear increase
Solution Approach 1:
The multi-layer joint insert acts as an intermediary component between the exhaust manifold and support bracket. It distributes thermal stresses across multiple layers and prevents direct stress concentration at the fastener interfaces, reducing wear and extending the life of the mechanical connection.
Solution Approach 2:
The joint insert uses composite construction with multiple metal sheet layers of different materials or properties joined together. This composite structure provides differentiated thermal and mechanical characteristics that reduce overall thermal stress and wear at the joint.
3Ease of manufacture
If a single-layer joint insert is used, then manufacturing simplicity is improved, but stress distribution and wear resistance decrease
Solution Approach 1:
The joint insert is divided into multiple metal sheet layers that can move independently relative to each other. This segmentation allows each layer to accommodate thermal growth differently, reducing stress concentration at the joint while maintaining overall structural support.
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 multi-layer joint insert reduces wear and failure of components by allowing sliding movement and mitigating thermally-induced stresses, thereby extending the lifespan of exhaust manifolds, support brackets, and fasteners.
Implementation Method 1
significant amounts of thermal growth can occur between the hot exhaust manifold and the support bracket. Such differential thermal growth generates stresses at the mechanical joints
Implementation Method 2
an anti-friction material is provided at the interface between the first and second metal sheet layers
Data Source
AI summary
A multi-layer joint insert is provided at one or more joints between an engine exhaust manifold and a component mounted by fasteners on the exhaust manifold, as well as between the component and the fastener heads/nuts, to reduce wear and failure at the one or more joints. The joint insert includes a first sheet metal layer having at least one fastener-receiving opening and a second sheet metal layer having at least one fastener-receiving opening, wherein the first and second sheet meal layers are joined by at least one connecting arrangement that permits relative sliding movement between the first and second sheet metal layers in response to thermally-induced movement at the one or more joints, thereby reducing wear and failure at the one or more joints.