Fuel Cell Freeze Preparation Scheduling for Low-Noise Purging
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Solution Overview
Problem
Vehicle fuel cell systems face issues with ice formation due to moisture accumulation, which can block vents and affect performance, especially under low ambient temperatures, and existing methods for moisture removal, such as high-speed compressor operation, are inefficient and may negatively impact customer perception.
Innovation Solution
A controller-programmed system that initiates a purge of the fuel cell system by flowing air through it using a compressor when the vehicle is approaching its destination, based on proximity and state of charge thresholds, to prevent ice formation and efficiently manage fuel cell operation, including restarting the fuel cell system if auto stopped.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-speed compressor operation is used to remove moisture from the fuel cell system, then moisture removal effectiveness is improved, but noise level increases and customer perception deteriorates
Solution Approach 1:
The system performs moisture removal (purge) operations in advance during normal driving conditions before freeze conditions occur. By proactively removing moisture during warm conditions when the vehicle is already running, the system eliminates the need for high-speed compressor operation during cold conditions, thereby avoiding noise complaints while maintaining moisture removal effectiveness
Solution Approach 2:
The system takes preliminary action to prevent ice formation by removing moisture before freeze conditions set in. The controller monitors temperature and moisture levels, and initiates purge operations before the fuel cell system is exposed to freezing temperatures, thereby preventing the harmful effect of ice formation without requiring noisy high-speed compression during cold conditions
2Reliability
If purge operation is performed continuously to remove moisture, then moisture accumulation is prevented, but energy consumption increases
Solution Approach 1:
Instead of continuous purge operation, the system implements periodic purge cycles based on monitored conditions. The controller activates the purge function only when specific conditions are met (temperature thresholds, moisture levels, driving mode), allowing moisture removal to occur intermittently rather than continuously, thereby reducing overall energy consumption while maintaining effective moisture prevention
Solution Approach 2:
The system uses feedback from sensors monitoring moisture levels, temperature, and system state to control purge operation timing and duration. By continuously monitoring system conditions and adjusting purge activation accordingly, the system performs moisture removal only when necessary, optimizing the balance between moisture accumulation prevention and energy consumption
3Reliability
If fuel cell system is kept running to prevent moisture accumulation, then system reliability is improved, but fuel consumption increases
Solution Approach 1:
The system performs preliminary moisture removal during normal operation before shutdown is required. By completing purge operations while the fuel cell is still running and conditions are favorable, the system can then safely shut down the fuel cell during idle periods without risking moisture accumulation, thereby maintaining reliability while reducing fuel consumption during non-driving periods
Solution Approach 2:
The system uses its own operational state to perform moisture removal services. During normal driving when the fuel cell is already running and producing power, the system utilizes this operational state to simultaneously perform the purge function, eliminating the need for separate dedicated purge operations that would consume additional fuel
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 proactively addresses moisture accumulation, enhances fuel cell performance, reduces noise from high-speed compressor operation, and enables faster fuel cell warm-up by initiating freeze preparation proactively during the journey, improving overall system efficiency and customer experience.
Implementation Method 1
a purge of the fuel cell system by flowing air through it to remove moisture from the system
Implementation Method 2
The reaction in such a fuel cell involves hydrogen molecules splitting into hydrogen ions and electrons at the anode and causing the electrons to pass through an external load circuit to the cathode side
Data Source
AI summary
The disclosure relates to a vehicle with a traction battery and a fuel cell system, and a controller programmed to purge the fuel cell system by flowing air through it to remove moisture from the fuel cell system. The controller is configured to initiate the purge based on a distance of the vehicle from a destination, a state of charge of the traction battery, and ambient temperature conditions at the destination. The freeze preparation process can be initiated when the vehicle is approaching its destination and can be predicted using connectivity and communication with off-board sources.