Partial Back Plate Compressor Axial Thrust Mitigation
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Solution Overview
Problem
Turbocharger systems experience excessive axial thrust loading due to pressure imbalances between the front and back faces of compressor and turbine wheels, leading to increased friction loss and reduced durability in the thrust bearing system, particularly in systems with axial turbines or electric motors.
Innovation Solution
The implementation of a turbocharger system with a partial back plate compressor and regenerative back-to-back turbo pump and hydraulic turbine configurations, which dissipate pressure through cut-outs and counterbalancing mechanisms to reduce axial thrust loads on the turbine shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a conventional compressor with full back plate is used, then structural strength is maintained, but excessive axial thrust load is generated on the turbine shaft
Solution Approach 1:
The back plate of the compressor impeller is segmented by introducing cut-out sections (radial slots) that divide the continuous back plate into separate regions. This segmentation allows pressure equalization between the front and back faces of the impeller, reducing the axial thrust load while maintaining sufficient structural strength through the remaining plate material.
Solution Approach 2:
Material is extracted from the back plate by creating cut-out sections, removing the portion that contributes to excessive pressure differential. This extraction reduces the axial force generated by the pressure imbalance while the remaining plate structure maintains the necessary mechanical strength for compressor operation.
2Force
If pressure is dissipated through cut-out sections, then axial thrust load is reduced, but compressor manufacturing complexity increases
Solution Approach 1:
The back plate is segmented into discrete regions separated by cut-out sections, which can be manufactured using standard machining operations. The segmentation pattern is regular and repetitive, making it suitable for conventional manufacturing processes while effectively reducing axial thrust load through pressure equalization.
3Reliability
If axial thrust load is reduced through design modifications, then bearing system durability is improved, but device complexity increases
Solution Approach 1:
The simplest modification to the compressor structure - adding cut-out sections to the back plate - is implemented to reduce axial thrust load. This design change directly improves thrust bearing durability by reducing the load they must support, without requiring complex additional components or systems.
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 solution effectively reduces axial thrust loads, minimizing friction loss and enhancing the durability and transient response time of the turbocharger system by balancing thrust forces and reducing pressure exposure on seals and bearings.
Implementation Method 1
the high pressure at the back-face of the compressor is dissipated through the cut out sections from the back-face of the compressor to the front-face of the compressor
Implementation Method 2
the inclusion of the back-to-back turbo pump may be used to generate balanced thrust load on the shaft
Data Source
AI summary
Methods and systems are provided for a turbocharger system to reduce and balance axial thrust load on the turbine shaft and the associated bearing system and sealing. In one example, a partial back plate compressor may be used in combination with an axial turbine to reduce axial thrust load and to improve turbocharger transient response time. In another example, a regenerative turbocharger system with back-to-back turbo pump may be used to reduce and balance axial thrust load.