Fuel Cell Pump Current Feedback for Coolant Leak Detection
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Solution Overview
Problem
Existing systems for detecting cooling fluid loss in fuel cell thermal sub-systems often result in false alarms and inadequate response to small leaks, as they rely solely on level sensors and do not effectively differentiate between fluid level changes due to leaks and other conditions, such as vehicle maneuvers, leading to potential overheating and component damage.
Innovation Solution
A method utilizing current feedback from a high temperature pump to monitor and compare the actual current with expected current levels, incorporating a diagnostic counter to verify low cooling fluid conditions over time, and adjusting pump speed for accurate measurements, thereby initiating appropriate mitigating actions like warning indicators or system shutdowns only when a significant leak is confirmed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a level sensor is used to detect cooling fluid loss, then the system can detect fluid level changes, but it cannot differentiate between actual leaks and false alarms caused by vehicle maneuvers
Solution Approach 1:
The system uses pump current feedback to detect changes in pump load that indicate cooling fluid loss. The controller continuously monitors the current drawn by the pump and compares it to expected current values, using this feedback to reliably detect actual leaks while filtering out false alarms from vehicle maneuvers.
Solution Approach 2:
The pump current serves as an intermediary indicator of cooling fluid level. Instead of directly measuring fluid level with a level sensor, the system uses the pump's electrical current consumption as a proxy measurement, which indirectly reflects the pump's load and the presence of adequate cooling fluid.
2Temperature
If the pump speed is increased to improve cooling, then the cooling effectiveness is improved, but the current measurement accuracy decreases making leak detection difficult
Solution Approach 1:
The system dynamically adjusts the pump speed based on detected conditions. When a potential leak is detected through current analysis, the controller can modify pump operation to optimize both cooling performance and measurement accuracy, allowing the system to adapt to different operating conditions.
3Difficulty of detecting and measuring
If a dedicated level sensor is employed to detect cooling fluid level, then the detection capability is provided, but it causes false indications during vehicle maneuvers such as sharp turns
Solution Approach 1:
The system replaces the mechanical level sensor approach with an electrical measurement approach using pump current monitoring. This substitution eliminates the mechanical sensor's susceptibility to false readings during vehicle maneuvers, as electrical current measurements are not affected by gravitational effects on fluid level.
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 provides a reliable and timely detection of cooling fluid loss, reducing the risk of fuel cell stack overheating by differentiating between actual leaks and false alarms, ensuring accurate and targeted responses to maintain system safety and performance.
Implementation Method 1
a high temperature pump that pumps the cooling fluid through a coolant loop
Implementation Method 2
where a radiator typically cools the cooling fluid when it exits the stack
Implementation Method 3
A hydrogen fuel cell is an electro-chemical device that includes an anode and a cathode with an electrolyte therebetween
Data Source
AI summary
A system and method for determining a loss of cooling fluid from a thermal sub-system in a fuel cell system. The method includes monitoring current feedback from a high temperature pump that pumps the cooling fluid through a coolant loop. A measured current from the pump is compared to an expected current for the system operating conditions, and if that current is significantly less than what is expected, then it may be as a result of low cooling fluid. If the measured current is less than the expected current for a predetermined period of time, then the system can take mitigating action as a result of a low cooling fluid. Further, if the pump speed is too low to provide an accurate current measurement, then it can be increased if an overflow tank level sensor indicates a low cooling fluid level.