Turbocharger Scroll Casing with Segmented Surface Roughness
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Solution Overview
Problem
High surface roughness of the inner wall surface in exhaust turbocharger turbines leads to increased pressure loss and thermal energy loss, reducing turbine efficiency, while treatments to reduce roughness increase manufacturing costs and decrease mass productivity.
Innovation Solution
A casing design for the exhaust turbocharger turbine with a spiral scroll that partitions its surface into two ranges, one with reduced surface roughness from the winding start to a predetermined angle and another with higher roughness, preventing thermal and pressure losses without the need for extensive surface treatment, thus maintaining cost-effectiveness and productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If treatment for reducing surface roughness is performed over the entire circumference of the scroll, then turbine efficiency is improved, but manufacturing cost increases and mass productivity declines
Solution Approach 1:
The scroll's inner wall surface is segmented into two distinct ranges: a first range (0-180 degrees) with reduced surface roughness and a second range (180-360 degrees) with higher surface roughness. This segmentation allows selective application of surface treatment only where most beneficial, avoiding the need to treat the entire circumference, thereby maintaining turbine efficiency while improving mass productivity and reducing manufacturing costs.
Solution Approach 2:
Different surface quality characteristics are applied to different regions of the scroll's inner wall surface. The first range (0-180 degrees) has low surface roughness to minimize thermal energy loss and pressure loss, while the second range (180-360 degrees) has higher surface roughness. This local differentiation optimizes performance where needed without incurring the costs and productivity losses associated with treating the entire surface.
2Loss of energy
If treatment for reducing surface roughness is performed over the entire circumference of the scroll, then thermal energy loss and pressure loss are prevented, but manufacturing cost increases
Solution Approach 1:
The scroll's inner wall surface is segmented into two distinct ranges: a first range (0-180 degrees) with reduced surface roughness and a second range (180-360 degrees) with higher surface roughness. This segmentation allows selective application of surface treatment only where most beneficial, avoiding the need to treat the entire circumference, thereby maintaining turbine efficiency while improving mass productivity and reducing manufacturing costs.
Solution Approach 2:
Different surface quality characteristics are applied to different regions of the scroll's inner wall surface. The first range (0-180 degrees) has low surface roughness to minimize thermal energy loss and pressure loss, while the second range (180-360 degrees) has higher surface roughness. This local differentiation optimizes performance where needed without incurring the costs and productivity losses associated with treating the entire surface.
3Loss of energy
If treatment for reducing surface roughness is performed over the entire circumference of the scroll, then pressure loss in exhaust gas flow is reduced, but mass productivity declines
Solution Approach 1:
The scroll's inner wall surface is segmented into two distinct ranges: a first range (0-180 degrees) with reduced surface roughness and a second range (180-360 degrees) with higher surface roughness. This segmentation allows selective application of surface treatment only where most beneficial, avoiding the need to treat the entire circumference, thereby maintaining turbine efficiency while improving mass productivity and reducing manufacturing costs.
Solution Approach 2:
Different surface quality characteristics are applied to different regions of the scroll's inner wall surface. The first range (0-180 degrees) has low surface roughness to minimize thermal energy loss and pressure loss, while the second range (180-360 degrees) has higher surface roughness. This local differentiation optimizes performance where needed without incurring the costs and productivity losses associated with treating the entire surface.
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 design enhances turbine efficiency by minimizing thermal and pressure losses while preventing increases in manufacturing costs and maintaining high mass productivity, making the exhaust turbocharger turbine more affordable and efficient.
Implementation Method 1
a spiral scroll as a path through which the exhaust gas is supplied to the turbine rotor
Implementation Method 2
heat transfer is promoted between the inner wall surface and the exhaust gas flow and energy loss arises
Data Source
AI summary
Provided is a casing 21 for an exhaust turbocharger turbine 2, configured so as to house a turbine rotor 23 to be driven by exhaust gas and form a spiral scroll 22 serving as a path for supplying the exhaust gas to the turbine rotor 23, wherein the scroll 22 includes a first region 222a extending from a spiral origin position 222s to a predetermined angle θ and a second region 222b extending from the predetermined angle θ to a spiral end position 222e, with the surface area of an interior wall thereof decreasing from the spiral origin position 222s toward the spiral end position 222e, and the interior wall at the first region 222a has a lower surface roughness than that at the second region 222b.