Fuel Cell Gas Recirculation Valves for Water and Impurity Separation

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Solution Overview

Problem

The frequent use of a drain valve in a fuel cell system leads to increased wear and tear, as it is designed to release both water and impurities, which can reduce the durability of the valve.

Innovation Solution

A controller is implemented to manage the opening and closing of both a drain valve and an exhaust valve, selectively draining water when the gas-liquid separator is full and releasing impurities when their concentration exceeds a threshold, thereby reducing the frequency of drain valve use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the drain valve is used to release both water and impurities, then the system can maintain proper water levels and remove contaminants, but the frequency of drain valve use increases leading to reduced durability

Engineering Contradiction:
Improvedurability of drain valveVSAvoidfrequency of drain valve operation
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The invention divides the single drain valve into two separate functional components: a drain valve for water removal and an exhaust valve for impurity release. This segmentation allows each valve to perform its dedicated function, reducing the operational frequency of the drain valve and thereby improving its durability while maintaining effective system maintenance.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the drain valve operates frequently to remove impurities, then the circulating gas can be kept clean, but the wear and tear on the drain valve increases

Engineering Contradiction:
Improvepurity of circulating gasVSAvoidservice life of drain valve
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The invention separates the functions of water drainage and impurity exhaust into two distinct valves. The exhaust valve handles impurity release while the drain valve focuses solely on water removal, thereby maintaining circulating gas purity without subjecting the drain valve to excessive operational wear.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The exhaust valve acts as an intermediary component specifically for impurity removal. By introducing this intermediate element, the system can release impurities without requiring the drain valve to operate frequently, thus preserving the drain valve's service life while maintaining gas purity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If the drain valve is used for both water drainage and gas release, then the system design can be simplified, but the operational complexity and wear on the valve increase

Engineering Contradiction:
Improvenumber of valves in systemVSAvoiddurability of drain valve
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

Although adding a second valve increases the nominal number of components, the segmentation of functions reduces operational complexity for each individual valve. The drain valve and exhaust valve each have dedicated, simplified functions, which improves reliability and reduces wear on the drain valve despite the increased component count.

Inventive Principle:
Principle #1Segmentation

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 approach enhances the durability of the drain valve by minimizing its operation frequency and preventing excessive gas release, maintaining system efficiency and reducing wear.

Implementation Method 1

a gas-liquid separator provided in the circulating path, the gas-liquid separator being configured to separate water contained in the circulating gas from the circulating gas

Methodology Applied
Scientific EffectGravitational separation: Gravitation

Implementation Method 2

a gas-liquid separator provided in the circulating path, the gas-liquid separator being configured to separate water contained in the circulating gas from the circulating gas

Methodology Applied
Scientific EffectDensity difference separation: Density Gradient

Data Source

PatentEP4636871A1Fuel cell system
Publication Date: 2025.10.22 TOYOTA JIDOSHA KK
  • EP4636871A1 patent drawingFigure 1
  • EP4636871A1 patent drawingFigure 2
  • EP4636871A1 patent drawingFigure 3

AI summary

A fuel cell system (1) includes a controller (50) configured to control opening and closing of a drain valve (28) and opening and closing of an exhaust valve (29). The controller (50) is configured to, when an amount of water stored in a gas-liquid separator (27) is larger than or equal to a predetermined value, open the drain valve (28) to drain, via the drain valve (28), the water stored in the gas-liquid separator (27). The controller (50) is configured to, when a concentration of impurities contained in circulating gas is higher than or equal to a predetermined value, open the exhaust valve (29) to release, via the exhaust valve (29), the circulating gas circulating in the circulating path (23).