Refrigerated cargo container cargo sensor
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Solution Overview
Problem
Frost or ice accumulation on cargo sensors in refrigerated truck compartments leads to sensor inoperability and false positive indications due to low-temperature conditions, limiting their effectiveness.
Innovation Solution
A cargo detection system with a temperature sensor and controller that activates only when the temperature is above a threshold, combined with a sensor bracket that improves airflow and is positioned near a defroster heater to reduce ice accumulation, ensuring accurate cargo presence detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cargo sensor operates continuously in the refrigerated cargo container, then the cargo presence detection coverage is improved, but the sensor becomes inoperable or gives false positive indications due to ice accumulation
Solution Approach 1:
The defroster heater is activated before the cargo sensor begins operation to pre-prevent ice accumulation on the sensor surface. This preliminary heating action ensures the sensor remains operational and accurate during cargo detection in the refrigerated environment
Solution Approach 2:
The defroster heater, which generates heat as a byproduct of its operation, is strategically positioned to utilize this heat to prevent ice accumulation on the cargo sensor. The harmful cold environment that causes ice formation is converted into a beneficial heating source for sensor protection
2Measurement precision
If the cargo sensor is positioned to detect cargo effectively, then the detection accuracy is improved, but the sensor temperature drops below freezing causing ice accumulation
Solution Approach 1:
The sensor bracket acts as an intermediary thermal barrier between the cold refrigerated cargo container environment and the cargo sensor. This bracket provides thermal isolation that maintains the sensor temperature above freezing while still allowing the sensor to detect cargo presence accurately in its operational position
3Reliability
If the sensor bracket provides thermal isolation to prevent ice accumulation, then the sensor reliability is improved, but the air flow to the sensor is restricted
Solution Approach 1:
The sensor bracket provides thermal isolation at the specific location of the cargo sensor, creating a localized warm zone around the sensor while maintaining cold temperatures in the rest of the cargo container. This localized approach prevents ice accumulation on the sensor without restricting the overall air flow needed for refrigeration efficiency
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
The solution effectively prevents false data collection and maintains sensor functionality by ensuring the cargo sensor operates above freezing temperatures, enhancing the reliability of cargo detection in refrigerated environments.
Implementation Method 1
A temperature sensor is located at the cargo sensor body and is configured to detect a temperature of the cargo sensor body
Implementation Method 2
The defroster heater and the cargo sensor are located such that activation of the defroster heater increases a temperature of the cargo sensor
Implementation Method 3
Cargo compartment air is passed over the coils of the evaporator, boiling the refrigerant flowing through the evaporator coil, thus heat is absorbed from the air in the conditioned compartment to cool the conditioned compartment
Data Source
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AI summary
A cargo detection system for a refrigerated cargo container includes a cargo sensor body configured to detect presence of cargo in a refrigerated cargo container and a sensor bracket configured for securing the cargo sensor body at a refrigeration unit of the refrigerated cargo container. A temperature sensor is located at the cargo sensor body and is configured to detect a temperature of the cargo sensor body. A temperature controller is operably connected to the temperature sensor and is configured to activate the cargo sensor body for collection of data when the temperature of the cargo sensor body is above a threshold.