Fuel Cell Power Control for Fewer Stop-Restart Cycles
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Solution Overview
Problem
Conventional fuel cell vehicle systems experience rapid degradation and reduced performance due to frequent unnecessary stops and restarts, which are not adequately controlled by preset reference values, leading to inefficiencies and durability issues related to altitude, coolant temperature, and fuel cell degradation.
Innovation Solution
A method for controlling fuel cell power generation in fuel cell vehicles by determining a reference output based on vehicle driving conditions, including altitude and coolant temperature, and the degree of fuel cell degradation, using correction values from Equations 1 and 2 to adjust the reference output for restarting and stopping, thereby minimizing unnecessary stops and restarts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power generation of the fuel cell is controlled to restart when the required torque exceeds a reference torque, then the vehicle can maintain driving capability, but frequent unnecessary stops and restarts occur leading to rapid fuel cell degradation
Solution Approach 1:
The patent changes the control parameter from a fixed reference torque value to a dynamic reference torque that varies with coolant temperature. Specifically, the reference torque is adjusted based on the coolant temperature to account for the fuel cell's degraded performance at low temperatures, preventing unnecessary restarts while maintaining adequate driving capability.
Solution Approach 2:
The patent implements feedback control by continuously monitoring the coolant temperature and adjusting the reference torque accordingly. The control system uses the coolant temperature information to dynamically modify the restart criterion, creating a closed-loop control that adapts to the fuel cell's thermal state and degradation level.
2Use of energy by moving object
If the power generation of the fuel cell is controlled to stop when the required torque is less than a reference torque, then energy efficiency can be improved, but unnecessary stops and restarts accelerate performance degradation
Solution Approach 1:
The patent modifies the stop control parameter by introducing coolant temperature-dependent reference torque values. The reference torque for stopping is set higher when coolant temperature is low, preventing stops that would occur under normal conditions but are unnecessary when the fuel cell is thermally constrained, thus preserving performance while maintaining energy efficiency.
3Device complexity
If a preset reference value is used for controlling fuel cell restart and stop, then the control system is simple, but it does not account for fuel cell degradation and operating conditions leading to frequent unnecessary stops and restarts
Solution Approach 1:
The patent introduces a single additional parameter (coolant temperature) to the control system to adjust the reference torque values. This minimal parameter addition accounts for thermal effects on fuel cell performance without significantly increasing system complexity, striking a balance between simplicity and durability.
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 improves fuel cell performance and lifespan by reducing degradation, enhancing durability and efficiency by optimizing power generation control based on actual vehicle needs and fuel cell condition, minimizing the frequency of stops and restarts.
Implementation Method 1
the oxidation reaction of hydrogen occurs at the anode to generate protons and electrons, and the generated protons and electrons move to the cathode through an electrolyte membrane and a separator, respectively. At the cathode, water is generated through the electrochemical reaction of the protons and electrons moved from the anode and the oxygen in the air, and the flow of these electrons generates electric energy.
Data Source
AI summary
Disclosed is a method for controlling a fuel cell of a fuel cell vehicle. The method comprises determining a reference output required for restarting or stopping power generation of a fuel cell according to a required output of a vehicle, correcting the reference output based on vehicle driving condition information comprising a vehicle altitude and coolant temperature and degree of degradation of the fuel cell, and restarting or stopping the power generation of the fuel cell based on the corrected reference output.