Fuel Cell Vehicle Standby Current Control for Low-Temperature Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Fuel cell vehicles experience prolonged standby times at low temperatures, leading to decreased user convenience and unstable power generation due to insufficient moisture in the fuel cell stack, which affects fuel efficiency.
Innovation Solution
A fuel cell vehicle system with a control section that manages the fuel cell stack's power generation current by switching between a high increase rate during operation and a lower increase rate during standby, charging a battery with the fuel cell stack's power and adjusting current rates based on temperature information to maintain stability and shorten standby times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the amount of reactant gas is rapidly increased to shorten standby power generation time, then the standby time is reduced, but the power generation becomes unstable due to insufficient moisture in the fuel cell stack
Solution Approach 1:
The patent applies dynamics by switching between two different current increase rates (first current increase rate and second current increase rate) based on the power generation current relative to the standby switching current value. This dynamic adjustment allows the system to rapidly increase current initially to shorten standby time, then slow down the increase rate to maintain power generation stability when moisture becomes insufficient.
Solution Approach 2:
The patent changes the parameter of current increase rate from a constant value to a variable value that switches between two different rates. The first current increase rate is used when power generation current is below the standby switching current value, and the second current increase rate (lower than the first) is used when power generation current exceeds the standby switching current value, thereby optimizing both standby time and power generation stability.
2Reliability
If the fuel cell system performs standby power generation at low temperature to prevent freezing, then the fuel cell stack is protected from freezing, but the ease of use decreases due to prolonged standby time during which travel manipulations are not accepted
Solution Approach 1:
The system dynamically adjusts the current increase rate during standby power generation based on real-time monitoring of power generation current against the standby switching current value. This dynamic control enables the system to protect the fuel cell stack from freezing while minimizing standby time, thereby improving user convenience without sacrificing reliability.
Solution Approach 2:
By changing the current increase rate parameter from fixed to variable (switching between first and second rates), the system optimizes the balance between protecting the fuel cell stack at low temperatures and reducing standby time to improve ease of operation.
3Device complexity
If the fuel cell system uses a simple configuration to achieve power generation stability, then the device complexity is reduced, but the ability to significantly shorten standby time is compromised
Solution Approach 1:
The patent implements a dynamic control mechanism that switches between two current increase rates based on operational conditions. This relatively simple dynamic control approach (comparing current against a threshold and switching rates) achieves significant standby time reduction without requiring complex system configuration, thus maintaining low device complexity while improving time efficiency.
Solution Approach 2:
The system achieves standby time reduction through parameter changes (switching current increase rates) rather than through complex structural modifications. This keeps the device configuration simple while effectively shortening standby 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 significantly reduces standby time while ensuring power generation stability and improving fuel efficiency by balancing reactant gas supply with moisture levels in the fuel cell stack.
Implementation Method 1
a fuel cell system including a fuel cell stack (12) and a battery (Bt) that is charged with power generated by the fuel cell stack (12)
Implementation Method 2
a battery (Bt) that is charged with power generated by the fuel cell stack (12)
Data Source
AI summary
A fuel cell vehicle is mounted with a fuel cell system including a fuel cell stack and a battery. The fuel cell vehicle controls operation of the fuel cell system with an ECU, to perform standby power generation from activation to when travel is allowed and to perform power generation during operation of the fuel cell vehicle after travel has been allowed. In an activation method, the power generation current is increased in accordance with a low-temperature efficiency rate during the power generation during operation, the battery is charged and the power generation current is increased in accordance with a standby current increase rate that is lower than the low-temperature efficiency rate during the standby power generation.