Check Valve Flow Path Layout for Pressure Fatigue Life
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Solution Overview
Problem
The existing valve devices for fuel cell vehicles experience a decrease in pressure fatigue life due to repeated pressure fluctuations at bending portions during gas charging and discharging, leading to stress concentration and potential failure.
Innovation Solution
A valve device with a check valve mechanism and drive mechanism that includes a main valve and pilot valve, where the intersecting portion of the first and second flow paths is located closer to the tank, reducing pressure changes and stress, and a solenoid drive mechanism that opens the pilot valve first to minimize pressure differences before opening the main valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the flow path is configured with bending portions to connect inlet and outlet flow paths, then the valve device can achieve compact design and efficient gas flow control, but the bending portions are exposed to repeated pressure fluctuations during gas charging and discharging, causing stress concentration and reduced pressure fatigue life
Solution Approach 1:
The flow path is segmented into multiple sections: a first flow path for gas charging, a second flow path for gas discharging, and an intersecting portion where they connect. The check valve mechanism is strategically positioned at the intersecting portion to segment the pressure fluctuation zones, allowing each section to experience reduced and differentiated pressure variations, thereby extending the pressure fatigue life of bending portions.
Solution Approach 2:
The check valve mechanism acts as an intermediary element at the intersecting portion of the flow paths. It mediates the pressure transmission by allowing gas to flow from the first flow path to the second flow path while preventing reverse flow, thereby reducing the direct transmission of high-frequency pressure fluctuations to the bending portions and extending their fatigue life.
2Ease of operation
If a solenoid valve is used to control gas flow for fuel cell supply, then precise gas flow control is achieved, but the solenoid valve is exposed to high pressure (87.5 MPa) and frequent opening/closing operations, leading to increased wear and reduced reliability
Solution Approach 1:
The check valve mechanism performs preliminary action by pre-regulating the pressure and flow direction before the gas reaches the solenoid valve. This preliminary pressure reduction and flow control minimize the stress and wear on the solenoid valve during its opening and closing operations, thereby extending its lifespan while maintaining precise control capability.
Solution Approach 2:
The check valve mechanism serves as an intermediary between the high-pressure gas source and the solenoid valve. It mediates the pressure and flow conditions, providing a more favorable operating environment for the solenoid valve by reducing peak pressure exposure and controlling flow direction, which reduces wear and improves reliability.
3Reliability
If the valve device is designed with larger dimensions to withstand high pressure and fatigue, then pressure fatigue life is improved, but the device size and manufacturing cost increase
Solution Approach 1:
Instead of uniformly increasing the size of the entire valve device, the invention applies local quality enhancement by strategically positioning the check valve mechanism at the intersecting portion where pressure fluctuations are most severe. This localized solution protects critical bending portions from fatigue without requiring overall device enlargement, thereby maintaining cost-effectiveness while improving pressure fatigue life.
Solution Approach 2:
The invention changes the pressure parameters experienced by different parts of the flow path through the check valve mechanism. By creating differentiated pressure zones and reducing peak pressure fluctuations at critical locations, the device can maintain adequate fatigue life with smaller dimensions, avoiding the cost increase associated with oversized components.
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 reduces the adverse effects on pressure fatigue life by minimizing stress at the bending portions and allows for a smaller, more efficient valve device design, effectively extending the lifespan of the valve and reducing size and cost.
Implementation Method 1
A solenoid valve 140 is disposed in the flow path 135. When the solenoid valve 140 is opened, the flow path 135 communicates with the storage chamber.
Implementation Method 2
The check valve mechanism is configured to open the valve when the gas is charged and close the valve when the gas charge is completed
Data Source
AI summary
A valve device includes a body having a gas flow path. When the gas is charged, the first flow path is located upstream of the intersecting portion, and the second flow path is located downstream of the intersecting portion. The gas flow path has a check valve mechanism and a drive mechanism. The check valve mechanism opens a valve when the gas is charged and closes the valve when the gas charge is completed, and the drive mechanism opens the valve of the check valve mechanism and holds the open state of the valve of the check valve mechanism when the gas is discharged from the tank. The check valve mechanism includes a valve seat, and the valve seat is disposed in the first flow path.