Fuel Cell Vehicle Scavenging Control via Atmospheric Pressure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing fuel cell vehicles face challenges in maintaining an optimal humid state during start-up operations below freezing temperatures, leading to variations in impedance that can result in either excessive or insufficient drying of the fuel cell stack, particularly in high-altitude and low-temperature regions.
Innovation Solution
A method for setting a scavenging period based on atmospheric air pressure, using a fuel cell vehicle equipped with an atmospheric air pressure acquisition unit and a pump to supply oxygen-containing gas to the cathode flow field, ensuring the cathode flow field is maintained in a humid state for stable start-up operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the scavenging period is set based on mass flow rate using a linear table, then the scavenging control is simplified, but the impedance variation after start-up below freezing temperature increases and the fuel cell stack cannot be dried to the suitable humid state
Solution Approach 1:
The invention changes the parameter basis for scavenging period determination from mass flow rate to atmospheric air pressure. By using atmospheric air pressure as the basis and applying correction coefficients for temperature and humidity, the system achieves more accurate impedance control during cold start-up while maintaining operational simplicity through standardized lookup tables and correction factors.
2Loss of substance
If the scavenging period is set to dry the fuel cell stack thoroughly, then water removal is improved, but the fuel cell stack may be dried excessively in high-altitude and low-temperature regions
Solution Approach 1:
The invention applies local quality by introducing region-specific correction coefficients that account for local environmental conditions (temperature, humidity, atmospheric pressure). The correction coefficient table provides different scavenging period adjustments based on specific temperature and humidity conditions, allowing the system to adapt the drying intensity to match local requirements and prevent both over-drying and under-drying.
Solution Approach 2:
The system uses feedback by incorporating temperature and humidity sensors to monitor actual environmental conditions during scavenging operations. This real-time data feeds into the correction coefficient selection, allowing dynamic adjustment of the scavenging period to achieve optimal water removal without excessive drying, thereby maintaining start-up performance reliability.
3Loss of substance
If the scavenging period is extended to ensure adequate drying, then water removal is improved, but the time required for system shutdown increases
Solution Approach 1:
The system performs preliminary action by pre-calculating and storing optimal scavenging periods and correction coefficients in lookup tables based on anticipated operating conditions. When scavenging is required, the system quickly retrieves the appropriate parameters and applies correction factors based on measured temperature and humidity, avoiding the need for extended trial-and-error scavenging operations and reducing overall shutdown 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 allows for consistent placement of the cathode flow field in an optimum humid state, reducing impedance variations and improving start-up performance regardless of the location's altitude or air density.
Implementation Method 1
a pump configured to suck the atmospheric air and supply an oxygen-containing gas to the cathode flow field through a supply channel
Implementation Method 2
a fuel cell stack including a plurality of power generation cells (unit cells) which perform power generation by electrochemical reactions of a fuel gas and an oxygen-containing gas
Data Source
AI summary
A fuel cell vehicle includes a fuel cell stack including a cathode flow field and an anode flow field, an atmospheric air pressure acquisition unit for obtaining pressure of atmospheric air, and a pump for sucking the atmospheric air and supplying an oxygen-containing gas to the cathode flow field through a supply channel. In the case where the temperature is predicted to be below freezing temperature after the time of stopping operation of the fuel cell stack, a scavenging period for the time of stopping operation is set based on the atmospheric air pressure, in order to perform scavenging of the cathode flow field by the oxygen-containing gas in a manner that the cathode flow field is placed in a predetermined humid state.