Turbocharger Diffuser Component Fills Impeller Housing Gap
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Solution Overview
Problem
In turbochargers, downsizing the compressor impeller leads to a gap between the impeller and the bearing housing, reducing compression efficiency and increasing costs due to the need for shape changes in components, and increasing the moment of inertia, which degrades responsiveness.
Innovation Solution
A turbocharger design that includes a diffuser component with a diffuser surface extending between the bearing housing and the compressor impeller to fill the gap, using a snap ring and insert component to fix the diffuser component in place, enhancing compression efficiency while allowing common use of bearing housing components and reducing pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the compressor impeller is downsized, then the moment of inertia decreases and responsiveness improves, but a gap is formed between the impeller and bearing housing that reduces compression efficiency
Solution Approach 1:
A diffuser component is introduced as an intermediary element between the compressor impeller and bearing housing. This diffuser component fills the gap formed by downsizing the impeller, preventing air leakage into the bearing housing while maintaining the compact impeller design for improved responsiveness.
Solution Approach 2:
The bearing housing is divided into functional zones by introducing the diffuser component. The diffuser component creates a dedicated diffuser flow path that separates the compression function from the bearing support function, allowing the impeller to be downsized without compromising compression efficiency.
2Volume of moving object
If the radially inner portion of the bearing housing is downsized to match the smaller impeller, then component costs increase due to shape changes in thrust plate and insert component
Solution Approach 1:
The diffuser component enables the bearing housing to maintain its original design dimensions while accommodating a smaller impeller. This allows existing thrust plates and insert components to continue being used without shape modifications, preserving manufacturing economy and component universality across different turbocharger configurations.
Solution Approach 2:
The diffuser component acts as a mediator that allows the bearing housing to serve multiple functions: supporting the smaller impeller while maintaining its original geometry for cost-effective manufacturing and enabling air flow management through the diffuser flow path.
3Loss of energy
If the radially outer portion of the compressor impeller is extended to fill the gap, then compression efficiency improves, but the moment of inertia increases and responsiveness degrades
Solution Approach 1:
Instead of extending the impeller radially outer portion, a diffuser component is introduced as an intermediary to fill the gap. This allows the impeller to maintain its compact size for low moment of inertia and high responsiveness while the diffuser component ensures compression efficiency by preventing air leakage and guiding flow properly.
Solution Approach 2:
The gap-filling function is separated from the impeller and assigned to a dedicated diffuser component. This segmentation allows the impeller to be optimized for rotational performance (small size, low inertia) while the diffuser component handles the flow management and gap sealing function.
Data Source
AI summary
A turbocharger according to one embodiment of this invention includes: a rotation shaft; a compressor impeller; a compressor housing; a bearing housing connected to the compressor housing and configured to define a diffuser flow path between the bearing housing and the compressor housing; a thrust plate configured to support the rotation shaft in an axial direction; an insert component configured to retain the thrust plate between the insert component and a protruding wall portion in the bearing housing; a snap ring configured to be inserted in a first circumferential groove formed in an inner peripheral wall surface of the bearing housing, to thereby fix the insert component in a state in which the insert component is pressed against the thrust plate; and a diffuser component having a diffuser surface extending along a direction orthogonal to an axis of the rotation shaft between the inner peripheral wall surface of an end portion of the bearing housing on one side thereof and an outer peripheral edge of the compressor impeller.