Fuel Cell Air Blower Control for Dry Out Prevention
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Solution Overview
Problem
Fuel cell systems face challenges in controlling power generation stop and restart, particularly in preventing dry out and improving fuel efficiency, especially during idle stops and reacceleration, due to inadequate management of air supply and energy recovery.
Innovation Solution
A method and system for controlling the fuel cell system by adjusting the connection state of pipes using a valve between the air blower and the cathode, allowing for independent control of airflow rates and regenerative braking, which determines the dry state of the fuel cell stack and adjusts air supply accordingly to prevent dry out and optimize energy recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the air blower is stopped to improve fuel efficiency during idle stop, then energy consumption is reduced, but the fuel cell stack may experience dry out
Solution Approach 1:
The air supply system is segmented into two independent controllable paths: one for power generation mode and another for dry out prevention mode. The controller selectively activates appropriate pipes and valves based on operational state, allowing independent control of air supply to different regions of the fuel cell stack.
Solution Approach 2:
Before completely stopping the air blower, the system performs preliminary actions by opening bypass pipes and adjusting valves to maintain minimum air flow through selected channels. This preliminary air supply prevents the fuel cell stack from entering a dry state before the power generation mode fully terminates.
2Speed
If the air blower is rapidly stopped to improve response time during reacceleration, then system responsiveness is improved, but energy recovery through regenerative braking is reduced
Solution Approach 1:
The system implements dynamic control of the air blower stopping process, transitioning from rapid stop to controlled deceleration based on real-time conditions. The controller adjusts the stopping rate to balance responsiveness requirements with energy recovery opportunities, making the system adaptable to different operational scenarios.
Solution Approach 2:
The controller changes the operational parameters of the air blower during the stopping process, adjusting rotation speed and air flow rate progressively. By modifying these parameters dynamically during deceleration, the system maximizes regenerative braking energy recovery while still achieving timely response for reacceleration.
3Loss of energy
If the air supply is completely cut off to maximize fuel efficiency during idle stop, then energy consumption is minimized, but drivability is degraded due to extended restart time
Solution Approach 1:
Instead of completely cutting off air supply, the system applies partial action by maintaining minimum air flow through bypass pipes during idle stop. This partial air supply is sufficient to prevent dry out and reduce restart time, while consuming minimal additional energy compared to complete shutdown.
Solution Approach 2:
Bypass pipes and control valves serve as intermediary elements between the air blower and the fuel cell stack. These intermediaries enable flexible control of air flow, allowing the system to maintain protective minimum flow levels during idle stop without requiring full power generation mode operation.
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 reduces the time for maintaining open circuit voltage, prevents fuel cell stack dry out, improves durability, enhances reacceleration responsiveness, and minimizes fuel efficiency loss by optimizing energy recovery through controlled airflow and regenerative braking.
Implementation Method 1
hydrogen is electro-chemically oxidized in the anode, and oxygen is electro-chemically reduced in the cathode. Electricity and heat are generated through movement of electrons produced at that time
Implementation Method 2
An air supply system supplies inhaled external air to a cathode of the fuel cell stack by operating an air blower
Implementation Method 3
A connection state of pipes connected to a valve is controlled by adjusting the valve disposed between an exit side of the air blower and an entrance side of a cathode of the fuel cell stack
Data Source
AI summary
A method of controlling a fuel cell system includes decelerating the air blower that stops power generation of a fuel cell stack or supplies air to the fuel cell stack. A connection state of pipes connected to a valve is controlled by adjusting the valve disposed between an exit side of the air blower and an entrance side of a cathode of the fuel cell stack. According to the present disclosure, the time of maintaining open circuit voltage (OCV) can be reduced, and the dry out of the fuel cell stack can be prevented to improve durability of the fuel cell.