Fuel Cell Injector Control for Off-Gas Circulation Stability
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Solution Overview
Problem
Existing fuel cell systems face challenges in stably circulating fuel off-gas and efficiently draining produced water while preventing stoichiometric shortages and reducing noise and vibrations during operation, particularly due to alternating injector configurations that affect pressure pulsation and drainage efficiency.
Innovation Solution
A fuel cell system with multiple injectors in parallel, an ejector, and a control method that adjusts injection modes based on load states, allowing for simultaneous or staggered fuel gas injection to maintain consistent circulation characteristics, enhance drainage efficiency, and minimize noise and vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If two injectors alternately inject fuel gas from different directions to the throat portion of the ejector, then the fuel gas circulation can be maintained, but the circulation characteristics differ between injection cycles leading to unstable fuel off-gas circulation
Solution Approach 1:
The patent divides the single ejector into multiple ejectors (first ejector and second ejector), each with its own nozzle and diffuser. This segmentation allows each ejector to handle fuel gas injection independently, ensuring consistent circulation characteristics and stable fuel off-gas circulation without complex control mechanisms.
2Productivity
If fuel gas is alternately injected from two injectors, then the system operation can be maintained, but the pressure pulsation width is insufficient leading to stoichiometric shortage and poor drainage efficiency
Solution Approach 1:
The patent merges the functions of multiple injectors and ejectors into a coordinated system where first and second injectors feed into respective ejectors simultaneously. This combination generates sufficient pressure pulsation width in the fuel gas, enabling effective drainage of produced water from the fuel cell while preventing stoichiometric shortage.
3Object-affected harmful factors
If injectors operate alternately, then the system can function with simpler control, but noise and vibrations during injector operation increase
Solution Approach 1:
The patent implements periodic action by coordinating the operation of first and second injectors with first and second ejectors in a cyclic manner. The injectors are controlled to inject fuel gas at different timing intervals, which reduces noise and vibrations during injector operation while maintaining simple control mechanisms.
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
The system stabilizes fuel off-gas circulation, improves drainage efficiency, prevents stoichiometric shortages, and reduces noise and vibrations by adapting injection control modes according to load states, ensuring efficient operation and extended injector lifespan.
Implementation Method 1
one ejector disposed downstream of the plurality of injectors on the fuel gas supply path. The ejector includes: a diffuser; and a nozzle for guiding the fuel gas injected from the plurality of injectors to the diffuser
Implementation Method 2
a fuel cell for producing power by an electrochemical reaction between a fuel gas and an oxygen-containing gas
Data Source
AI summary
A fuel cell system includes a nozzle for guiding a fuel gas injected from a first injector and a second injector to a diffuser. An injector control portion performs a first injection control mode when a fuel cell stack is in a first load state. When the fuel cell stack is in a second load state, the injector control portion switches between a second injection control mode and a third injection control mode depending on the circumstances.