Hydrogen Injector Intermittent Failure Detection Strategy
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Solution Overview
Problem
Conventional injector diagnostic techniques are inadequate for detecting intermittent failures in hydrogen gas fuel injectors for fuel cell stacks, particularly when the injector fails to open at the specified time due to issues like ice formation or pintle wear, leading to reduced fuel delivery and stack instability.
Innovation Solution
A system and method that operates the injector at a fixed pulse width and frequency to maintain a constant current and fuel consumption rate, monitoring pressure feedback to detect any divergence from a nominal value, which indicates an intermittent opening failure, and adjusts the current to overcome potential friction issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional injector diagnostic techniques are used, then the system can operate with standard monitoring, but intermittent injector failures cannot be detected
Solution Approach 1:
The system performs preliminary diagnostic actions by operating the injector at a fixed pulse width and frequency during a specific diagnostic mode to establish baseline pressure feedback before normal operation resumes. This preliminary testing phase allows detection of intermittent failures that would not manifest during standard variable operation.
Solution Approach 2:
The system implements feedback monitoring by continuously observing pressure feedback from the fuel cell stack during injector operation. When the injector operates at fixed parameters, any deviation in pressure feedback from expected values indicates an intermittent opening failure, enabling real-time detection and diagnosis.
2Adaptability or versatility
If the injector operates at variable pulse width and frequency during normal operation, then fuel delivery adapts to load demands, but pressure feedback varies making failure detection difficult
Solution Approach 1:
The system segments injector operation into distinct modes: normal variable operation for fuel delivery adaptation, and a separate fixed-parameter diagnostic mode for failure detection. This segmentation allows the system to maintain adaptability during normal operation while achieving measurement precision during diagnostics by isolating the injector to fixed pulse width and frequency conditions.
3Reliability
If the injector current is increased to overcome friction issues, then the injector may open more reliably, but energy consumption increases
Solution Approach 1:
The system applies partial excessive action by temporarily increasing injector current above normal operating levels during the fixed-parameter diagnostic mode. This excessive current application is limited to specific diagnostic periods rather than continuous operation, allowing the system to overcome friction-induced opening delays and detect reliability issues without sustaining high energy consumption during normal variable operation.
Data Source
AI summary
A system and method for detecting an intermittent failure of an injector that injects hydrogen gas fuel into the anode side of a fuel cell stack in a fuel cell system. The method includes operating the injector at a fixed injector pulse width and frequency, which causes the stack to generate a constant current, and therefore, a constant fuel consumption rate. While at a constant current, the injector is commanded to a constant duty cycle and frequency that matches the rate of fuel consumption in the fuel cell system. The resulting fuel pressure feedback is then monitored, and if it diverges from a defined nominal value, either in a constant or oscillatory manner, it can be determined that the injector has an intermittent opening failure. In one embodiment, the determination of the injector failure is performed during a shut-down sequence of the fuel cell system.