Exhaust Manifold Partial Flange Thermal Expansion
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Solution Overview
Problem
The existing exhaust manifolds for internal combustion engines face challenges in maintaining a sufficient sealing effect and extending the lifespan due to thermal expansion differences between the manifold and the cylinder head, leading to material fatigue or rupture.
Innovation Solution
The flange is divided longitudinally into partial flanges that can independently vary in length with temperature changes, with a reinforcing plate bridging the gap between them, allowing for sliding in the flange plane and improving sealing and stability by distributing thermal expansion and preventing lifting or bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the screw connection is configured to minimize thermally induced relative movement between flange and cylinder head, then sealing is improved, but extreme stresses are formed in the housing leading to fatigue or rupture
Solution Approach 1:
The flange is divided into two separate partial flanges that can move independently relative to each other in the longitudinal direction. This segmentation allows each partial flange to expand thermally without generating extreme stresses in the housing, while still maintaining sealing contact with the cylinder head through the screw connection.
2Strength
If the screw connection is configured to allow free thermal movement of the flange, then housing stresses are reduced, but relative change in position between inlet pipes and cylinders occurs affecting sealing and flow conditions
Solution Approach 1:
By dividing the flange into partial flanges, the system allows controlled thermal movement within segments while maintaining overall positioning. The partial flanges can slide in the flange plane to accommodate thermal expansion, yet the screw connection points maintain sufficient contact for sealing and proper inlet pipe alignment.
3Ease of manufacture
If the flange is made as a single piece, then manufacturing is simpler, but thermal expansion causes lifting, bending, or buckling of the flange
Solution Approach 1:
The flange is segmented into multiple partial flanges connected by gaps. This segmentation prevents thermal expansion forces from causing overall flange lifting, bending, or buckling, as each segment can expand independently. The gaps allow thermal movement while the individual partial flanges maintain structural integrity.
4Adaptability or versatility
If gaps are introduced between partial flanges, then thermal expansion is accommodated, but the flange structure becomes more complex
Solution Approach 1:
The flange is divided into partial flanges with gaps between them, creating a segmented structure that accommodates thermal expansion. While this increases structural complexity compared to a solid flange, the gaps are simple geometric features that are straightforward to manufacture and assemble, and they provide the necessary thermal adaptability.
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
This design enhances the sealing effect and extends the lifespan of the exhaust manifold by reducing thermal loading and allowing for balanced thermal expansion, while maintaining favorable flow conditions and preventing material fatigue.
Implementation Method 1
During operation of an internal combustion engine, the exhaust manifold frequently reaches significantly higher temperatures than the cylinder head. This leads to different thermal expansions, which is clearly noticeable particularly in a longitudinal direction of the exhaust manifold
Data Source
AI summary
The present invention relates to an exhaust manifold for an internal combustion engine, in particular in a motor vehicle, comprising a housing from which a plurality of inlet pipes emanate, which, in the built-in state, lead to cylinders of the internal combustion engine, and comprising a flange, which is welded to the inlet pipes and which, in the built-in state, is screwed to the cylinder head of the internal combustion engine by means of a screw connection. The fatigue strength of the exhaust manifold can be improved by subdividing the flange into at least two partial flanges in a longitudinal direction of the exhaust manifold.