Exhaust Manifold Curved Pipe Equalization
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Solution Overview
Problem
Existing exhaust manifolds for internal combustion engines result in unequal lengths of exhaust passages, leading to degraded sound quality and increased pressure loss due to large confluence angles, which affect engine performance and catalytic converter activation.
Innovation Solution
An exhaust manifold design with a primary pipe and secondary pipes that wind into the center axis of the primary pipe at multiple points, ensuring equalized pipe lengths and reduced confluence angles to minimize pressure loss and improve sound quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the branch pipes are arranged in parallel with equal lengths and connected to the collection pipe at large confluence angles, then the manufacturing is simplified, but the exhaust passage lengths become unequal and pressure loss increases
Solution Approach 1:
The patent applies curvature by winding the secondary exhaust pipes into the center axis of the primary exhaust pipe in a spiral or curved manner. This curved configuration allows the pipes to achieve equal lengths while maintaining compact space utilization and reducing the confluence angle, thereby resolving the contradiction between manufacturing simplicity and pressure loss reduction.
2Ease of manufacture
If the branch pipes are arranged in parallel with equal lengths, then the manufacturing is simplified, but the sound quality of exhaust is degraded due to unequal exhaust passage lengths
Solution Approach 1:
The curved or spiral winding of secondary exhaust pipes into the primary pipe center axis equalizes the exhaust passage lengths from all cylinders to the outlet. This equalization ensures that exhaust pulses from different cylinders arrive at the outlet in a more synchronized manner, improving sound quality while maintaining manufacturing simplicity.
3Ease of manufacture
If the confluence angles of the branch pipes relative to the collection pipe are relatively large, then the connection is simplified, but the flowing direction of the exhaust gas is largely changed and pressure drop increases
Solution Approach 1:
The patent employs curved piping that winds secondary exhaust pipes into the primary pipe's center axis, creating a gradual transition in flow direction. This curved configuration reduces abrupt directional changes at connection points, thereby minimizing pressure drop while maintaining ease of manufacture through standardized curved pipe components.
4Loss of time
If the total length of the exhaust manifold is shortened for quick catalytic converter activation, then the response time is improved, but the pipe lengths of individual exhaust passages may become unequal
Solution Approach 1:
The curved winding configuration of secondary pipes into the primary pipe allows for compact space utilization, thereby reducing the total length of the exhaust manifold for faster catalytic converter activation. Simultaneously, the curved design enables precise control of individual pipe lengths to maintain equalization, resolving the contradiction between response time and manufacturing precision.
Data Source
AI summary
An exhaust manifold connected to exhaust ports of at least three straightly-arranged cylinders of an internal combustion engine is constructed by a primary exhaust pipe which extends from the foremost cylinder of the cylinders in the rearward direction of the engine along the direction of the straight arrangement of the cylinders and a plurality of secondary exhaust pipes which extend from the other cylinders except for the foremost cylinder to the primary exhaust pipe. The secondary exhaust pipes are collected to the primary exhaust pipe so that downstream end portions of the secondary exhaust pipes are wound into the center axis of the primary exhaust pipe at a plurality of points on the center axis, respectively.