Anode Header Drain Valve Logic for Fuel Cell Bleed and Water Removal
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Solution Overview
Problem
Existing fuel cell systems rely on unreliable tilt angle sensors to determine when to drain water from anode headers, leading to potential flooding and inefficiencies, particularly at maximum power operation.
Innovation Solution
Implementing an active valve system with an anode header drain valve that selectively bleeds nitrogen and drains water based on hydrogen concentration, eliminating the need for tilt angle sensors and minimizing power losses by replacing the bleed valve at maximum power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tilt angle sensors are used to determine when to drain water from anode headers, then the system can detect water accumulation, but the system reliability deteriorates due to sensor failure and the device complexity increases
Solution Approach 1:
The patent removes the tilt angle sensor from the system entirely, extracting the problematic component that caused reliability issues and complexity. The drainage function is achieved through a valve system controlled by hydrogen concentration sensors and control logic, eliminating dependence on tilt sensors while maintaining water removal capability.
Solution Approach 2:
The system uses its existing hydrogen concentration sensors and control logic to determine when drainage is needed, rather than relying on external tilt sensors. The control system self-regulates the drain valve based on internal measurements of hydrogen concentration, making the system self-sufficient and eliminating the need for additional sensors.
2Productivity
If the bleed valve is used for nitrogen removal during maximum power operation, then the exhaust gas can be bled, but power losses increase due to voltage dips
Solution Approach 1:
The patent divides the nitrogen removal function between two separate valves: the bleed valve handles nitrogen removal during normal operation, while the drain valve handles nitrogen removal during maximum power operation. This segmentation allows each valve to operate in its optimal regime, preventing the power losses associated with using the bleed valve at maximum power.
Solution Approach 2:
The system dynamically switches between using the bleed valve and drain valve for nitrogen removal based on the operational state. During maximum power operation, the drain valve is activated instead of the bleed valve, adapting the system's behavior to minimize power losses while maintaining effective nitrogen removal.
3Reliability
If the anode header drain valve is activated frequently for water drainage, then water accumulation is prevented, but the valve wear and system complexity increase
Solution Approach 1:
The system uses hydrogen concentration sensors to provide feedback on the state of the anode headers. When hydrogen concentration drops below a threshold, indicating water accumulation, the control logic activates the drain valve. This feedback mechanism ensures the valve is activated only when necessary, preventing both water accumulation and unnecessary valve wear.
Solution Approach 2:
The control system monitors hydrogen concentration as a parameter and uses this information to trigger drainage events. By changing the operational parameter from continuous drainage to event-driven drainage based on hydrogen concentration thresholds, the system reduces valve activation frequency while maintaining reliable water removal.
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 fuel cell system efficiency, durability, and reduces costs by eliminating the need for expensive tilt angle sensors, while preventing water accumulation and voltage dips during maximum power operation.
Implementation Method 1
hydrogen gas is catalytically split in an oxidation half-cell reaction in the anode catalyst layer to generate free hydrogen protons and electrons
Implementation Method 2
hydrogen gas is catalytically split in an oxidation half-cell reaction in the anode catalyst layer
Implementation Method 3
a solid polymer electrolyte (SPE) proton-conducting membrane, such as a perfluorosulfonic acid membrane, to separate product gases and provide electrical insulation of electrodes, in addition to conduction of protons
Implementation Method 4
a header drain valve that is fluidly connected to the anode exhaust header and selectively actuable to remove accumulated water from the anode exhaust header
Data Source
AI summary
Presented are intelligent fuel cell systems (FCS) with logic for evacuating water from anode headers of a fuel cell stack, methods for making/using such systems, and vehicles equipped with such systems. A method of operating an FCS includes a system controller confirming the FCS is running and, once confirmed, receiving a bleed request to remove exhaust gas from exhaust output by the anode. Responsive to the bleed request, the controller determines a total bleed valve use (TBVU) indicating prior bleed requests completed by an anode bleed valve, and thereafter determines if the TBVU is less than a maximum bleed valve use (MBVU). If so, the controller responsively commands the bleed valve to bleed the exhaust gas from the anode exhaust. If TBVU is not less than MBVU, the controller commands a header drain valve to bleed the exhaust gas from the anode exhaust and drain water from the anode header.