Fuel Cell System Pressure-Based Fuel Discharge Estimation
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Solution Overview
Problem
Existing fuel cell systems face challenges in accurately estimating the discharge amount of fuel gas due to intermittent injection, leading to potential waste and inefficiency.
Innovation Solution
A fuel cell system that includes a fuel injection portion, supply and circulation passages, a gas-liquid separator, a discharge passage with a valve, and a control unit that estimates the fuel gas discharge amount based on pressure changes and consumption rates during pressure increase and decrease periods, using detected pressure rates to calculate the lost and consumed fuel gas amounts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fuel gas is intermittently injected to the fuel cell, then the fuel cell operates efficiently with controlled fuel supply, but the pressure in the supply passage fluctuates between increase and decrease periods, making accurate estimation of fuel gas discharge amount difficult
Solution Approach 1:
The control unit performs preliminary identification of pressure increase periods (when pressure rises due to intermittent injection) and pressure decrease periods (when pressure falls). By detecting these periods in advance and treating pressure increase periods as equivalent to pressure decrease periods for calculation purposes, the system can accurately estimate fuel gas discharge amounts despite the fluctuating pressure conditions caused by intermittent injection.
2Reliability
If the discharge valve is opened to discharge stored water and fuel gas, then the gas-liquid separator maintains proper water levels, but the intermittent injection causes pressure fluctuations that reduce the accuracy of discharge amount estimation
Solution Approach 1:
The control unit continuously monitors pressure in the supply passage and uses this feedback to identify pressure increase and decrease periods. By incorporating real-time pressure feedback and adjusting the estimation calculation to account for intermittent injection effects, the system maintains accurate discharge amount estimation while the discharge valve operates to maintain proper water levels in the gas-liquid separator.
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 fuel gas discharge estimation, reducing waste and improving operational efficiency by precisely controlling the discharge amount and maintaining target discharge levels.
Implementation Method 1
a pressure detecting portion that detects pressure in the supply passage
Implementation Method 2
a gas-liquid separator that is arranged in the circulation passage and that stores and separates water from the fuel gas partially discharged from the fuel cell
Data Source
AI summary
A fuel cell system includes a control unit that estimates a discharge amount of the fuel gas partially discharged from the fuel cell partially discharged during an opening period of the discharge valve based on a lost amount of the fuel gas during the opening period and a consumed amount of the fuel gas by electric generation of the fuel cell during the opening period, wherein a pressure increase period during which the pressure increases and a pressure decrease period during which the pressure decreases exist due to intermittent injection of the fuel gas, and the control unit estimates the lost amount of the fuel gas based on a decrease rate of the pressure during the pressure decrease period within the opening period, and based on an assumed decrease rate of the pressure during the pressure increase period within the opening period.