Fuel Cell Pressure Reducing Valve With Upstream Flow Limiting Safety
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Solution Overview
Problem
Current pressure reducing valves in fuel cell vehicle systems lack sufficient safety measures to prevent high-pressure hydrogen from reaching the fuel cell group, risking damage and requiring additional safety systems for pressure regulation.
Innovation Solution
A pressure reducing valve with a secondary safety device that acts independently of the primary safety device to limit gas flow upstream when pressures exceed thresholds, complementing the existing primary safety device for sudden gas release, ensuring safe operation by blocking gas flow to the pressure reducer in case of overpressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a primary safety device (PRV valve) is used to release hydrogen when pressure exceeds a threshold, then overpressure protection is provided, but the system remains vulnerable if the pressure reducing valve fails to close properly or becomes jammed
Solution Approach 1:
The safety system is divided into two independent parts: a primary safety device (PRV valve) that releases overpressure downstream, and a secondary safety device that limits gas flow upstream. This segmentation ensures that if one safety device fails, the other can still protect the system.
Solution Approach 2:
The secondary safety device acts upstream of the pressure reducing valve to preemptively limit gas flow before excessive pressure can develop downstream. This preliminary action prevents the need for the primary safety device to activate in the first place.
2Reliability
If the pressure reducing valve closes tightly to prevent high-pressure hydrogen from reaching the fuel cell group, then safety is improved, but the risk of valve jamming or failure to open increases
Solution Approach 1:
The secondary safety device provides a backup protection mechanism that activates if the pressure reducing valve fails. It limits upstream gas flow to prevent excessive pressure buildup, cushioning against the harmful effects of valve failure.
Solution Approach 2:
The secondary safety device acts as an intermediary safety layer between the high-pressure hydrogen source and the pressure reducing valve. It monitors and limits gas flow independently, providing an additional layer of protection without interfering with the normal operation of the pressure reducing valve.
3Reliability
If a secondary safety device is added upstream of the pressure reducing valve, then safety is enhanced, but the device complexity increases
Solution Approach 1:
The secondary safety device is integrated into the existing valve body structure, sharing common components such as the valve body, seals, and control mechanisms with the pressure reducing valve. This merging approach adds safety functionality while minimizing the increase in overall system complexity.
Solution Approach 2:
The pressure reducing valve is designed to perform multiple functions: normal pressure reduction, overpressure protection through the primary safety device, and upstream flow limitation through the secondary safety device. This multi-functionality reduces the need for separate dedicated components for each safety function.
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
Enhances safety and reliability by preventing excessive gas flow to the pressure reducer, even when primary safety device activation occurs, thereby protecting the fuel cell system from high pressures and potential jams in the valve stages.
Implementation Method 1
a flow shutter (202) accommodated in said main compartment (102), which is configured to be hit by the gas flow passing from said upstream duct (100) towards said downstream duct (104) and movable beneath the action of said gas flow to limit the passage of gas from said upstream duct (100) towards said downstream duct (104)
Implementation Method 2
thrust means (210), comprising, for example, a spring (212), permanently acting on the flow shutter (202) to keep the gas passing from said upstream duct (100) to said downstream duct (104)
Implementation Method 3
a pressure reducing valve or HPR (6) valve, arranged downstream of the OTV (4) valve, adapted to reduce the pressure from an upstream value p1, with which the gas exits the OTV (4) valve, to a downstream value p2
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A pressure reducing valve (6) for a fuel cell vehicle system, comprises an inlet (24), an outlet (28), a first stage unit (40), a second stage unit (60) and a secondary safety device (200) acting between the inlet (24) and the first stage unit (40). The secondary safety device (200) is adapted to lower or stop the gas flow between the inlet (24) and the first stage unit (40) when the gas flow exceeds a preset threshold flow.