Fuel Cell Water Discharge Control via Dynamic Injector Actuation
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Solution Overview
Problem
During low load operation after high load conditions, stagnant water accumulates in fuel cell channels, leading to reduced power generation performance due to insufficient hydrogen gas flow from small flow rate injectors, making it difficult to maintain desired power generation states.
Innovation Solution
A fuel cell system with a control device that adjusts the drive cycle and flow rate of the fuel gas supply to extend the injection time and increase the quantity of hydrogen gas when excessive water content is detected, ensuring effective discharge of stagnant water from the fuel cell channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If only the small flow rate injector is actuated during low load operation to save energy, then energy consumption is reduced, but stagnant water cannot be discharged effectively and power generation performance deteriorates
Solution Approach 1:
The system dynamically switches between different injector configurations based on operational conditions. During normal low load operation, only the small flow rate injector is used to save energy. However, when stagnant water discharge is detected or required, the system transitions to actuate both small and large flow rate injectors simultaneously, creating a dynamic adaptation mechanism that resolves the contradiction between energy savings and water discharge effectiveness.
Solution Approach 2:
The invention changes the operational parameters of the fuel cell system by adjusting which injectors are actuated based on water accumulation conditions. The control device monitors water content and accordingly modifies the injector actuation state, switching from a single-injector mode (energy-saving) to a dual-injector mode (water-discharge mode), thereby adapting system parameters to resolve the performance-contradiction.
2Reliability
If the drive cycle is extended to increase hydrogen gas injection time, then stagnant water discharge is improved, but the injection frequency is reduced
Solution Approach 1:
The system applies partial action by extending the drive cycle only when and where needed for water discharge, rather than continuously. The control device determines based on water content detection whether to extend the drive cycle, applying the extended injection time partially during water accumulation conditions while maintaining normal frequency during dry conditions, thus resolving the contradiction between discharge effectiveness and overall productivity.
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 allows for reliable and efficient discharge of stagnant water, maintaining optimal power generation performance by increasing the anode differential pressure and extending the injection time, thereby addressing the issue of accumulated water during load transitions.
Implementation Method 1
a fuel cell for generating electrical energy by electrochemical reactions of an oxygen-containing gas and a fuel gas
Implementation Method 2
a fuel gas supply unit provided in the fuel gas supply pipe for injecting the fuel gas at every set drive cycle
Data Source
AI summary
A fuel gas supply apparatus of a fuel cell system includes a pressure reducing valve, an interruption valve, and an injector in a hydrogen supply channel. A controller of the fuel cell system includes a drive cycle setting unit for setting the drive cycle of the injector based on a load of the fuel cell stack, and a water state determination unit for determining whether or not quantity of water content in the fuel cell is excessive by determining whether or not the quantity of water content is a predetermined quantity or more.