Low Noise Valve Insert Body Flow Guidance
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Solution Overview
Problem
Existing canister purge valve assemblies generate objectionable noises due to aerodynamic stagnation and separation of gas flow, which are not effectively addressed by current noise mitigation strategies that either mask or absorb sound, leading to increased costs and design complexity.
Innovation Solution
A low noise valve assembly with an elastomeric valve and an insert body that is spatially segregated from the outlet tube, featuring a circular base with a diameter larger than the throat diameter, and a controlled height, which eliminates stagnation and separation zones by guiding fuel vapors smoothly across the valve seat, reducing noise generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a flat bottomed poppet valve is used to seal the valve seat, then the valve can be manufactured simply and cost-effectively, but flow-induced instability occurs causing objectionable whooshing noise and popping noise during operation
Solution Approach 1:
The valve is divided into two distinct parts: a flat bottomed poppet valve for sealing and an insert body with a curved leading edge for flow guidance. This segmentation allows each component to perform its specific function - the poppet valve maintains manufacturing simplicity while the insert body eliminates flow-induced noise by guiding vapor flow smoothly across the valve seat.
Solution Approach 2:
The insert body acts as an intermediary element between the incoming vapor flow and the flat bottomed poppet valve. It mediates the flow by providing a curved leading edge that guides the vapor smoothly across the valve seat, preventing direct impact and flow-induced instability that would cause noise, while allowing the simple poppet valve design to remain unchanged.
2Object-generated harmful factors
If acoustic absorbing material or dampers are added to reduce noise, then noise levels can be reduced, but system cost and design complexity increase
Solution Approach 1:
The insert body is integrated directly into the valve assembly as a unified component. By merging the flow guidance function into the valve structure itself, the solution eliminates the need for separate acoustic absorbing materials or dampers, thereby reducing noise while maintaining cost-effectiveness and design simplicity.
Solution Approach 2:
Instead of adding components to absorb or mask noise, the insert body converts the potentially harmful direct impact of vapor flow into beneficial smooth guidance across the valve seat. The curved leading edge transforms the flow pattern to eliminate flow-induced instability and noise generation at the source.
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
The solution significantly reduces whooshing noise levels by stabilizing downstream flow, achieving a 20% improvement in sound pressure levels and minimizing mechanical vibrations, while maintaining a cost-effective and design-intact solution.
Implementation Method 1
a stagnation of flow and separation occurs. The stagnation and separation zones under the valve are significantly unstable and result in local pressure pulsations and noise
Data Source
AI summary
A low noise valve assembly (24) mitigates noise induced by near sonic gas flow encountering stagnant flow in the region of the valve (24). An inlet tube (10) terminates in an annular chamber (12). An outlet tube (17) has a generally annular valve seat (14) disposed within the chamber (12). The valve (24) moves toward and away from a closed condition in direct contact with the valve seat (14). The valve (24) includes an insert body (26) that is spatially segregated from direct contact with the outlet tube (17) while partially filling the flow channel (16) of the outlet tube (17) when the valve (24) is in its closed condition. The insert body (26) has a generally circular base with a diameter that is larger than the throat diameter (T), which is the internal diameter of the flow channel (16) adjacent the valve (24).