Fuel Cell Refrigerant Pump Leak Detection
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Solution Overview
Problem
Existing fuel cell systems require a dedicated pressure sensor to detect leaks in the cooling water circulation circuit, increasing the number of system components and complexity.
Innovation Solution
A fuel cell system that uses a refrigerant pump with a controller to determine refrigerant leaks by correlating rotating speed and power consumption, eliminating the need for a dedicated pressure sensor, and optionally increasing the pump's rotating speed to enhance leak detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dedicated pressure sensor is provided for leak decision, then leak detection accuracy is improved, but the number of parts and device complexity increases
Solution Approach 1:
The refrigerant pump is made to serve dual functions: (1) delivering refrigerant to the fuel cell stack, and (2) enabling leak detection through power consumption measurement. By utilizing the pump's existing power consumption data, which would otherwise be just operational information, the system achieves leak detection capability without requiring a dedicated pressure sensor, thus applying the multi-functionality principle to resolve the contradiction between detection accuracy and device complexity
Solution Approach 2:
The refrigerant pump performs self-diagnosis by monitoring its own power consumption. The control unit compares the measured power consumption against predetermined thresholds to determine whether a leak has occurred. This self-service approach allows the pump to provide leak detection information without external dedicated sensors, reducing system complexity while maintaining detection capability
2Measurement precision
If pump rotating speed is increased to threshold value before leak decision, then leak detection accuracy is improved, but energy consumption increases
Solution Approach 1:
The control unit increases the refrigerant pump's rotating speed to a threshold value before executing the leak decision process. This preliminary action ensures that the pump operates at a speed where power consumption variations due to leaks are more definite and easier to detect. After the leak decision is made, the speed can be reduced, thus balancing detection accuracy requirements with energy consumption concerns through timed speed adjustments
Data Source
AI summary
A fuel cell system comprises a fuel cell, a cooling system, a rotating speed acquisition part acquiring a rotating speed of the refrigerant pump, a power consumption acquisition part acquiring a power consumption of the refrigerant pump, and a controller configured to receive a rotating speed acquired by the rotating speed acquisition part and control the refrigerant pump. The controller has stored therein a predetermined correspondence between rotating speeds of the refrigerant pump and power consumption threshold values. The controller executes a refrigerant leak decision process for deciding presence or absence of a refrigerant leak while executing constant rotating speed control for the refrigerant pump, and in the refrigerant leak decision process, with reference to the correspondence by using a rotating speed value acquired by the rotating speed acquisition part, the controller determines a power consumption threshold value corresponding to the rotating speed value, and decides that a refrigerant leak has occurred if a power consumption value acquired by the power consumption acquisition part is equal to or lower than the power consumption threshold value corresponding to the rotating speed value.