Fuel Cell Drain and Exhaust Valve Control for Impurity Separation

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Solution Overview

Problem

The frequent use of a drain valve in fuel cell systems leads to increased wear and tear, reducing its durability due to the simultaneous release of both water and impurities through the valve, which is exacerbated by the presence of impurities in the circulating gas.

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 water level exceeds a threshold and releasing impurities when their concentration is high, thereby reducing the frequency of drain valve use and minimizing excessive gas release.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the drain valve is used to drain water from the gas-liquid separator, then water removal is achieved, but the valve frequency of use increases leading to reduced durability

Engineering Contradiction:
Improvedrain valve durabilityVSAvoidwater drainage efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The invention divides the single drain valve function into two separate components: a drain valve for water removal and an exhaust valve for impurity gas release. This segmentation allows each valve to perform its dedicated function, reducing the drain valve's operational frequency and extending its durability while maintaining efficient water drainage capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention extracts the impurity release function from the drain valve operations. By introducing a separate exhaust valve that opens to release circulating gas containing impurities, the system removes the harmful function of impurity discharge from the drain valve's operational burden, allowing the drain valve to focus solely on water drainage with reduced usage frequency.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If the drain valve releases both water and impurities simultaneously, then both substances are removed, but the drain valve wear increases due to impurity presence

Engineering Contradiction:
Improvedrain valve lifespanVSAvoidimpurity contamination
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention segments the removal process into two distinct pathways: water is removed through the drain valve while impurity-containing gas is removed through the exhaust valve. This segmentation prevents impurities from contacting and damaging the drain valve, extending its lifespan while maintaining effective removal of both substances.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention extracts the impurity removal function from the drain valve system and assigns it to the exhaust valve. By opening the exhaust valve to release circulating gas before or during water drainage, impurities are removed separately without causing wear to the drain valve, eliminating the harmful effect of impurity contamination on the drain valve.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If the exhaust valve is opened frequently to release impurities, then circulating gas quality is maintained, but excessive gas release occurs wasting hydrogen

Engineering Contradiction:
Improvecirculating gas qualityVSAvoidhydrogen loss
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The invention implements feedback control by monitoring the concentration of impurities in the circulating gas and the amount of water in the gas-liquid separator. The controller opens the exhaust valve only when impurity concentration exceeds a threshold, and closes it when the concentration drops below the threshold, ensuring gas quality maintenance while minimizing unnecessary openings and hydrogen waste.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The invention uses parameter-based control where the exhaust valve operation is triggered by specific parameter thresholds (impurity concentration levels). This ensures the valve opens only when necessary to maintain gas quality, preventing excessive openings and associated hydrogen loss while still effectively managing circulating gas composition.

Inventive Principle:
Principle #35Parameter changes

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 extends the lifespan of the drain valve by optimizing its usage, ensuring efficient water drainage and impurity removal, thus maintaining system efficiency and preventing power generation inefficiencies.

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

Data Source

PatentEP4456215B1Fuel cell system
Publication Date: 2025.12.31 TOYOTA JIDOSHA KK
  • EP4456215B1 patent drawingFigure 1
  • EP4456215B1 patent drawingFigure 2
  • EP4456215B1 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).