Exhaust Gas Control Valve With Multi-Surface Seat For Precise Flow
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Solution Overview
Problem
Existing exhaust gas control valves in two-stage supercharging systems have a narrow control range for exhaust gas flow rates, particularly in low and medium engine RPM regions, leading to reduced full-load torque and difficulty in smoothly transitioning between two-stage and one-stage supercharging operations.
Innovation Solution
A fluid selection valve unit with a valve member and seat design where the passage area between the side end surface of the valve member and the side surface of the valve seat is smaller than the contact passage area, allowing for gentle variation of the passage area with the opening degree, enabling precise control of exhaust gas flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional exhaust gas control valve is used, then the valve structure is simple, but the control range for exhaust gas flow rates is narrow and the passage area varies abruptly with opening degree
Solution Approach 1:
The valve member is divided into multiple functional surfaces: a bottom surface for initial sealing, side end surfaces for gradual flow control, and a top surface for full opening. This segmentation allows different portions of the valve to perform different control functions at different opening stages, enabling gentle passage area variation while maintaining structural feasibility.
Solution Approach 2:
The invention transitions from conventional single-surface valve design to a multi-surface three-dimensional valve structure with bottom, side, and top surfaces. This dimensional complexity enables the passage area to vary gradually through multiple stages (bottom surface engagement → side surface engagement → full opening) rather than abruptly, improving control performance.
2Ease of operation
If the passage area varies abruptly with valve opening degree, then the valve structure is simple, but the transition between two-stage and one-stage supercharging operations is not smooth
Solution Approach 1:
The valve design creates a dynamic, multi-stage opening process where the passage area changes gradually through different geometric configurations. As the valve opens, flow transitions from bottom surface control to side surface control to full opening, providing smooth adaptation between supercharging modes rather than abrupt changes.
Solution Approach 2:
The invention changes the geometric parameters of the valve passage by incorporating multiple surfaces with different orientations and depths. This creates a progressive parameter change in the passage area as the valve opens, enabling smooth transition between supercharging operations and expanding the effective control range.
3Reliability
If the passage area is not carefully controlled, then the valve design is simple, but the full-load torque is reduced
Solution Approach 1:
Different surfaces of the valve member are designed with different local geometries optimized for specific functions: the bottom surface provides initial sealing and gradual opening, the side end surfaces control the transition phase with controlled passage area, and the top surface enables full opening. This local quality differentiation maintains full-load torque while managing complexity.
Data Source
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Figure 3A~3B
AI summary
A fluid selection valve unit is provided which is applicable to an exhaust gas control valve, a waste gate valve, or the like provided between a high-pressure-stage supercharger and a low-pressure-stage supercharger of a two-stage supercharging exhaust turbocharger so as to control an amount of exhaust gas supplied to the high-pressure-stage supercharger and the low-pressure-stage supercharger, and which is capable of improving control performance of a valve in such a manner that a passage area gently varies with respect to an opening degree of a valve member so as to minutely control an exhaust gas amount by using the opening degree of the valve. In a fluid selection valve unit including: a valve seat provided in a fluid passage; and a valve member of which one end is supported to a rotary shaft so as to be rotatable about a shaft center of the rotary shaft in a direction moving away from the valve seat, the valve seat includes a side surface having a predetermined depth and a bottom surface continuous to the side surface, the valve member includes a bottom portion and a side end surface formed above the bottom portion, and the valve member is configured so that a passage area of a gap formed between the side end surface of the valve member and the side surface of the valve seat is smaller than a contact passage area formed between the bottom portion of the valve member and the bottom surface of the valve seat during a time when the bottom portion of the valve member comes into contact with the bottom surface of the valve seat by the rotation of the rotary shaft, and the rotary angle increases up to a predetermined value of the rotary angle.