Refrigerant leak sensor pre-trip sequence and diagnostics
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Solution Overview
Problem
Transport refrigeration units lack effective pre-trip diagnostics and leak detection methods, leading to potential refrigerant leaks going undetected and resulting in inefficiencies and product downtime.
Innovation Solution
A system comprising a refrigerant leak sensor, a controller, and an evaporator fan that performs pre-trip sequence diagnostics, validates sensor operation, and conducts refrigeration tests to detect leaks, providing alarms and low charge diagnostics to differentiate between actual and false alarms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pre-trip diagnostics and leak detection methods are implemented, then refrigerant leak detection capability is improved, but device complexity increases
Solution Approach 1:
The system performs pre-trip diagnostics by validating sensor operation before the refrigeration unit departs. The controller executes a sequence that activates the refrigerant leak sensor and evaluates its readings in advance, ensuring the sensor is functional before actual operation begins. This preliminary validation prevents false negatives during actual trips without requiring continuous complex monitoring systems.
Solution Approach 2:
The system uses its own operational components (fan, compressor, sensor) to perform self-diagnosis. The controller activates the fan to circulate air and potential refrigerant leaks toward the sensor, then uses the sensor's own readings to detect leaks. This self-testing approach eliminates the need for external diagnostic equipment while maintaining detection capability.
2Measurement precision
If sensor validation and refrigeration tests are performed, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The system performs a focused pre-trip test sequence that validates sensor operation and checks for leaks only to the extent necessary for safety. Rather than continuous comprehensive testing, the controller executes a targeted sequence: activate fan, monitor sensor readings for predetermined time, evaluate results. This partial action approach provides sufficient detection precision while limiting time loss to a brief pre-trip window.
Solution Approach 2:
The system implements periodic diagnostics at scheduled intervals (pre-trip, during operation, post-trip) rather than continuous monitoring. The pre-trip sequence occurs periodically at the start of each trip, providing regular validation without requiring constant testing. This periodic approach balances measurement precision with time efficiency by concentrating testing efforts at critical transition points.
3Measurement precision
If low charge diagnostics calculations are implemented, then diagnostic accuracy is improved, but use of energy increases
Solution Approach 1:
The system replaces complex continuous monitoring mechanics with simplified periodic calculations. Instead of continuously calculating low charge diagnostics, the controller performs these calculations only during pre-trip sequences and when triggered by specific conditions. This substitution reduces the energy burden of computational operations while maintaining diagnostic accuracy at critical moments.
Solution Approach 2:
The system changes the operational parameters of diagnostics calculations by executing them at specific times (pre-trip, during low charge conditions) rather than continuously. The controller adjusts when these energy-intensive calculations occur based on system state and operational phase, reducing overall energy consumption while preserving diagnostic accuracy when most needed.
Data Source
AI summary
Embodiments are provided for a system configured to provide pre-trip sequence and diagnostics for refrigerant leak sensor. The system includes a sensor, a fan, and a controller. The controller is further configured to validate an operation of the sensor, operate the fan based at least in part on validating the operation of the sensor, and responsive to operating the fan, determine if a leak is present using the sensor. The controller is also configured to perform a refrigeration test, determine if a leak is present using the sensor, and provide an alarm based at least in part on determining the leak is present. Embodiments are also provided for a method for performing a pre-trip sequence and diagnostics for a leak sensor.