Wastegate Contoured Side Wall for Linear Flow Control
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Solution Overview
Problem
Conventional wastegate valves in turbochargers experience non-linear changes in flow rate with small actuation angles, leading to undesirable correlations between actuator angle and flow rate, making precise control of exhaust gas flow challenging.
Innovation Solution
The implementation of a contoured side wall near the valve in the wastegate assembly, which shifts the flow choking area from the valve curtain area to the throat area between the valve and the side wall, allowing for more gradual changes and precise control of exhaust gas flow by shaping the side wall with a radial offset and incorporating hole wells for fine-tuning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional wastegate valve is used with a straight port side wall, then the structure is simple and easy to manufacture, but the flow rate changes non-linearly with small actuation angles, making precise control difficult
Solution Approach 1:
The patent applies curvature by contouring the port side wall in the wastegate assembly. Instead of a straight side wall, the port side wall is shaped with a specific contour that creates a gradual change in the flow passage area. This curvature allows for more linear and predictable flow rate changes in response to valve actuation, enabling precise control of exhaust gas flow while maintaining manufacturing feasibility through standard machining or molding processes.
2Length of moving object
If the wastegate valve is actuated with small angles, then the actuator movement is limited and compact, but the flow rate changes non-linearly and unpredictably
Solution Approach 1:
The patent changes the geometric parameters of the port side wall to achieve a desired flow characteristic. By carefully designing the contour of the port side wall, the relationship between valve actuation angle and flow rate is transformed from non-linear to more linear. This allows small actuator strokes to produce predictable, proportional changes in flow rate, achieving precise control without requiring large actuator movements.
3Manufacturing precision
If a contoured side wall is implemented, then precise control of exhaust gas flow is achieved, but the device complexity increases
Solution Approach 1:
The patent applies local quality by contouring only the port side wall while leaving other components of the wastegate assembly unchanged. This localized modification achieves the desired flow control precision without requiring complex changes to the entire device. The contoured port side wall can be integrated into existing wastegate designs, adding minimal complexity to the overall system while significantly improving flow control characteristics.
Data Source
Figure 1~3
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Figure 6a
AI summary
A wastegate assembly (12) having a valve (16) to control exhaust gas flow bypassing a turbine wheel of a turbocharger. The wastegate assembly (12) has a wastegate port (14) for flow bypassing the turbine wheel. The valve (16) has an arm (20) controlling a valve head (22) relative to the port (14) for selectively blocking and unblocking the port (14) to control flow. A valve seat (26) may surround the port (14) to be operable with the valve head (22) to selectively block the port (14). A contoured side wall (30) is disposed adjacent to the port (14) and extends from the turbine housing (10) so as to be radially offset from a valve margin (25). The contoured side wall (30) may have a concave portion (40) adjacent to the valve head (22) to help effectuate desired flow at specific valve opening angles.