Exhaust Manifold Fixing Device Thermal Expansion
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Solution Overview
Problem
Existing motor vehicle heat engine exhaust gas collection systems face sealing issues due to differential thermal expansion between aluminum cylinder heads and steel or cast iron manifolds, leading to potential leaks and increased manufacturing complexity.
Innovation Solution
A fixing device with a deformable support plate and connection stiffeners that maintains the upper flange in constant contact with the cylinder head, absorbing thermal expansion differences and ensuring a secure seal, while being compact and adaptable to space constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid fixing system with flanges and bolts is used to attach the manifold to the cylinder head, then the attachment strength is improved, but sealing problems occur due to distortions from differential thermal expansion
Solution Approach 1:
The fixing bar changes its physical state from rigid to flexible by incorporating an elastic portion, allowing it to deform and accommodate differential thermal expansion between the aluminum cylinder head and steel manifold while maintaining sealing contact
Solution Approach 2:
The fixing system transitions from a static rigid connection to a dynamic flexible connection where the elastic portion of the fixing bar can deform elastically in response to thermal expansion differences, maintaining continuous contact and sealing
2Reliability
If additional machining of connecting surfaces is performed to accommodate fixing elements, then the sealing capability is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The fixing bar serves multiple functions: it provides mechanical attachment through the fixing portion and simultaneously ensures sealing through the bearing surface, eliminating the need for separate sealing components or additional machining operations
Solution Approach 2:
The sealing function is extracted from the cylinder head's connecting surface and integrated into the fixing bar's bearing surface, allowing the manifold and cylinder head to connect without requiring precision-machined connecting surfaces
3Device complexity
If a fixing bar without deformation zones is used, then the structural simplicity is improved, but the system cannot accommodate differential expansion leading to leaks
Solution Approach 1:
The fixing bar incorporates an elastic portion that changes its physical properties by allowing elastic deformation, enabling it to accommodate thermal expansion differences while maintaining a simple overall structure without complex deformation zones
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 effectively maintains a tight seal and absorbs thermal expansion, preventing leaks and reducing manufacturing costs by using a single plate for both the fixing and support functions, ensuring reliable attachment even under varying temperatures.
Implementation Method 1
said support plate (32) comprises an elastic part (37)
Implementation Method 2
differential expansion between the manifold and the wall of the cylinder head
Data Source
Figure 1~3
AI summary
The invention relates to a device (10) for attaching an exhaust gas collector (11) to a wall of the cylinder head (14) of a heat engine, said collector being extended by an end flange (20) comprising a lower strip (24) secured to the cylinder head and a diagonally opposite upper strip (23) comprising a contact surface (29), characterised in that the device comprises a attachment bar (30) comprising a plate (31) for attachment to the cylinder head and a plate (32) for pressing against the upper strip, having a shape which is complementary to the contact surface (29) of the upper strip and comprising a deformable elastic part.