Partition Wall Geometry in Forced-Induction Scroll Passages
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Solution Overview
Problem
Existing forced-induction devices face challenges in managing pressure pulsation and backflow of exhaust gases between different exhaust ports, leading to inefficiencies in gas flow and turbine wheel rotation due to differing combustion stroke timings in internal combustion engines.
Innovation Solution
A forced-induction device with a connection pipe featuring a partition wall that separates the exhaust gas flow into distinct passages, ensuring the distal end of the partition wall is positioned between imaginary lines orthogonal to the flow direction, minimizing backflow and collision with the partition wall, and maintaining equal cross-sectional flow areas for balanced gas contribution to the turbine wheel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If exhaust gases from multiple cylinders are merged in a common passage, then the device structure is simplified, but pressure pulsation and backflow increase due to different combustion stroke timings
Solution Approach 1:
The connection pipe is segmented into multiple separate passages (first passage, second passage, etc.) corresponding to different exhaust ports. Each passage handles exhaust gases from specific cylinders independently, preventing interference between gases at different pressure stages. This segmentation resolves the contradiction by maintaining structural simplicity while eliminating pressure pulsation and backflow through separate flow paths.
2Object-affected harmful factors
If the partition wall is extended further into the connection pipe, then backflow between passages is reduced, but collision with the partition wall increases and flow smoothness deteriorates
Solution Approach 1:
The partition wall is designed with specific local geometry: it extends only to a controlled position within the connection pipe, and its cross-sectional shape is optimized to match the passage configuration. The partition wall includes curved surfaces that guide flow smoothly rather than creating sharp edges. This local quality optimization reduces backflow while minimizing collision, resolving the contradiction between preventing harmful backflow and avoiding flow disruption.
3Productivity
If exhaust passages are arranged to accommodate different combustion timings, then gas flow balance is improved, but the device structure becomes more complex
Solution Approach 1:
Multiple separate passages carrying exhaust gases from different cylinders are merged into a single scroll passage that leads to the turbine wheel. The merging is designed so that gases from different combustion strokes are combined in a controlled manner within the scroll passage, maintaining balanced flow distribution. This merging approach achieves improved gas flow efficiency while avoiding excessive structural complexity by using a unified scroll passage design.
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 enables smooth exhaust gas flow into the scroll passage, reduces backflow, and maintains consistent turbine wheel rotation speed by minimizing pressure pulsation and ensuring balanced gas contribution, thereby enhancing the efficiency of the forced-induction device.
Implementation Method 1
a turbine wheel (14), a turbine housing (15) that accommodates the turbine wheel (14)
Implementation Method 2
The scroll passage (18) communicates with the first passage (21) and the second passage (22) such that exhaust gas that has passed through the first passage (21) and exhaust gas that has passed through the second passage (22) merge with each other
Data Source
AI summary
A forced-induction device includes a turbine wheel and a partition wall that partitions the interior of a connection pipe into a first passage and a second passage. When viewed in a cross section orthogonal to a rotation axis of the turbine wheel, a line segment connecting the rotation center of the turbine wheel and a downstream end of an inner wall in a flow direction of exhaust gas is a first line segment. A straight line orthogonal to the first line segment and extending from the downstream end in the flow direction of the exhaust gas is a first imaginary line. A straight line passing through a proximal end of the partition wall and orthogonal to an inflow direction of the exhaust gas is a second imaginary line. The distal end of the partition wall is located between the first imaginary line and the second imaginary line.