Fuel Cell Pressure Control Valve Backflow Prevention
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Solution Overview
Problem
The existing fuel cell systems face efficiency degradation when the booster pump is driven with minimum output due to inappropriate pressure settings, leading to excessive fuel flow rates and backflow issues.
Innovation Solution
A fuel cell system with a pressure control valve that sets a predetermined negative pressure to ensure a flow rate less than the minimum requirement, using a raw material pump with the minimum pump opening degree, and includes a flow rate sensor and gas leakage detection to prevent backflow and optimize fuel supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a needle valve is used to hold discharge side pressure lower than atmospheric pressure to prevent backflow, then backflow prevention is achieved, but fuel flow rate becomes excessive when the booster pump is driven with minimum output, degrading generation efficiency
Solution Approach 1:
The patent changes the pressure parameter from holding pressure lower than atmospheric pressure to holding pressure higher than atmospheric pressure. This parameter change resolves the contradiction by preventing backflow while ensuring the fuel flow rate remains above the minimum required flow rate even when the booster pump operates at minimum output, thus maintaining generation efficiency.
2Object-generated harmful factors
If pressure on the discharge side is held to be lower than atmospheric pressure using the needle valve, then backflow to the recycling flow path is prevented, but the fuel flow rate exceeds the minimum requirement when the booster pump is driven with minimum output
Solution Approach 1:
The patent applies parameter change by reversing the pressure condition from lower than atmospheric pressure to higher than atmospheric pressure. This ensures that the fuel flow rate through the booster pump remains sufficient (above minimum required flow rate) while still preventing backflow to the recycling flow path, thus addressing both the harmful backflow and excessive fuel flow rate issues.
3Reliability
If the needle valve is set with inappropriate pressure, then backflow prevention is compromised, but setting pressure too low causes excessive fuel flow rate and efficiency degradation
Solution Approach 1:
The patent resolves this contradiction by changing the pressure parameter setting from below atmospheric pressure to above atmospheric pressure. This optimized parameter setting ensures reliable backflow prevention while maintaining appropriate fuel flow rates that prevent energy loss and preserve generation efficiency, even when the booster pump operates at minimum output.
Data Source
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AI summary
A fuel cell system includes: a fuel cell (34) generating electricity using a fuel and an oxidant gas; a reforming unit (33) generating the fuel from a raw reforming material from a raw reforming material supply source and reforming water, and supplying the fuel to the fuel cell; a desulfurizer (11a6) removing a sulfur component contained in the raw reforming material and supplying the desulfurized raw reforming material to the reforming unit; a raw reforming material supply pipe (11a) causing the raw reforming material to be fed to the desulfurizer; a raw material pump (11a5) provided in the raw reforming material supply pipe and supplying the raw reforming material to the desulfurizer; a recycling fuel pipe (39) causing a portion of the fuel to return to an introduction side of the raw material pump; and a pressure control valve (11a4) provided on the raw reforming material supply pipe.