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 actuator angle, leading to undesirable control over exhaust gas flow and turbine speed, necessitating more precise control over valve opening and flow area.
Innovation Solution
A contoured side wall is introduced near the valve, shifting the flow control 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 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 operation
If a conventional wastegate valve is used with a pivotable lever arm, then the valve can be actuated to control exhaust gas flow, but the flow rate changes non-linearly with actuator angle resulting in undesirable control
Solution Approach 1:
The patent changes the geometric parameters of the wastegate assembly by introducing a contoured side wall with specific radial offset dimensions. This modifies the flow area characteristics to achieve a linear relationship between actuator angle and flow rate, transforming the non-linear control behavior into linear control behavior for precise flow regulation.
Solution Approach 2:
The patent employs a contoured side wall with curved geometry rather than a straight or flat configuration. This curvature is specifically designed to modify the flow passage area as a function of valve opening angle, creating a linear flow characteristic that improves control precision while maintaining ease of operation.
2Length of moving object
If the lever arm length is reduced to minimize hinge movement, then packaging constraints are improved, but the curtain area changes very large and non-linearly with small actuation angles
Solution Approach 1:
The patent compensates for the non-linear flow changes caused by short lever arm actuation by modifying the side wall contour geometry. The contoured side wall creates a flow passage whose area changes linearly with valve opening, counteracting the non-linear effects of short lever arm rotation and enabling precise flow control with compact dimensions.
Solution Approach 2:
Instead of relying solely on lever arm geometry for flow control, the patent introduces a new dimensional element - the contoured side wall profile. This adds a geometric dimension to the flow control mechanism that independently regulates the flow area, decoupling the relationship between actuator displacement and flow rate for more precise control.
3Productivity
If flow control is achieved through valve curtain area, then the valve can regulate exhaust gas flow, but the control is non-linear and interferes with turbine exhaust flow
Solution Approach 1:
The patent segments the flow control function by separating the valve curtain area from the primary flow control role. Instead, the contoured side wall creates a dedicated throat area that serves as the primary flow control point, while the valve curtain area is reduced to a secondary function. This segmentation allows for more precise and linear flow regulation with reduced interference to turbine exhaust flow.
Solution Approach 2:
The contoured side wall acts as an intermediary element between the valve and the exhaust gas flow. It creates a throat area that mediates the flow control process, providing a more linear and predictable flow characteristic compared to direct valve curtain area control. This intermediary structure reduces harmful non-linear effects and minimizes interference with the main turbine exhaust flow path.
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 configuration provides consistent and precise control over exhaust gas flow, reducing interference with turbine exhaust flow and enabling more gradual changes in valve opening, resulting in improved control over turbine speed and boost pressure.
Implementation Method 1
A flow control method includes shaping a side wall of a port adjacent to a valve of a wastegate assembly with a radial offset from a port valve side adjacent to a wastegate port. The radial offset creates a contoured side wall that forms a throat area between the valve and the side wall.
Data Source
AI summary
A wastegate assembly with a valve head moved linearly toward and away from a wastegate port via a valve stem. When the valve is in an open position the valve seat face of the valve head is spaced apart from the valve seat. When the valve is in a closed position the valve seat face of the valve head is secured against the valve seat. The wastegate assembly includes a sidewall surrounding the wastegate port elongated in the direction of valve movement. The contoured side wall widens going away from the valve seat. The minimum flow area through the wastegate port is controlled such that the flow is choked via the side wall rather than the valve curtain area. The contoured side wall can be recessed into the housing or extend from the housing.