Fuel Cell Anode Gas Discharge Estimation via Pressure Stabilization
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Solution Overview
Problem
The existing fuel cell systems have limitations in accurately estimating the amount of anode gas discharged during the discharge valve open-period due to intermittent gas injection, leading to inaccuracies in pressure estimation.
Innovation Solution
A fuel cell system with a controller that adjusts the injector and discharge valve operations to maintain a predetermined target pressure, closes the discharge valve when a target discharge amount is reached, and extends the first period after gas injection stops until pressure variation falls within a range, thereby increasing the ratio of this period to the drive cycle, allowing for improved anode gas discharge estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the discharge valve is opened to discharge anode gas, then the amount of discharged gas can be controlled, but the pressure fluctuates due to intermittent injector operation making accurate estimation difficult
Solution Approach 1:
The patent extracts the pressure measurement period from the continuous drive cycle by identifying and isolating the first period (from injector stop until pressure variation falls within predetermined range). This allows pressure measurement to be performed during a stable sub-period, separating the measurement function from the fluctuating injection cycle and improving estimation accuracy.
Solution Approach 2:
The system performs preliminary action by controlling the injector to maintain pressure at or above a target value before discharge valve operation. This preliminary pressure control creates a stable baseline condition, ensuring that subsequent pressure measurements during the first period accurately reflect discharged gas amounts rather than pressure fluctuations from inadequate supply pressure.
2Stress or pressure
If the injector operates intermittently to supply anode gas, then pressure can be maintained at target levels, but the discharge amount estimation becomes inaccurate due to repeated pressure increases and decreases
Solution Approach 1:
The patent extracts a stable measurement window (first period) from within the intermittent injection cycle. By measuring pressure change specifically during this extracted period when the injector is stopped and pressure is stabilizing, the system eliminates the measurement errors caused by intermittent pressure fluctuations while maintaining the necessary intermittent injection for pressure control.
Solution Approach 2:
The system applies partial action by performing pressure measurement only during the specific first period rather than continuously throughout the drive cycle. This partial measurement approach focuses resources on the most informative time window, achieving accurate discharge estimation without requiring continuous measurement during all injection fluctuations.
3Measurement precision
If the measurement period is extended to improve estimation accuracy, then more data is available for calculation, but the response time and control efficiency decrease
Solution Approach 1:
The patent applies partial action by measuring pressure change only during the specific first period (from injector stop until pressure variation stabilizes) rather than requiring measurement over the entire drive cycle. This partial period measurement provides sufficient data for accurate discharge estimation while minimizing the time required, achieving an optimal balance between measurement precision and control response time.
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 the accuracy of anode gas discharge estimation by prolonging the period used for pressure measurement, leading to more precise control and efficient operation.
Implementation Method 1
a pressure sensor located on a downstream side of the injector in the anode gas supply channel or on the anode gas discharge channel
Implementation Method 2
an injector located on the anode gas supply channel and configured to inject the anode gas
Implementation Method 3
a discharge valve located on the anode gas discharge channel
Implementation Method 4
a fuel cell configured to generate electric power by receiving supply of an anode gas and a cathode gas
Data Source
AI summary
In a fuel cell system including a fuel cell, an anode gas supply channel, an anode gas discharge channel, an injector, a pressure sensor, and a controller, the controller controls the injector so that the pressure on the downstream side of the injector in the anode gas supply channel and does not become lower than target pressure, closes a discharge valve when the amount of discharged anode gas reaches a target discharge amount, the amount of discharged anode gas estimated based on the amount of decrease in the value of the pressure in a first period of the discharge valve open-period, the first period being a period from the point of time after the injector stops the injection and when variation of the pressure falls within a predetermined range to the point of time when the injector next starts the injection, and increases a ratio of the first period to the drive cycle by controlling, during the discharge valve open-period, at least one of the anode gas supply rate of the injector, the amount of electric power generated by the fuel cell, and the drive cycle of the injector.