Apparatus and method for thermal event detection in a transport refrigeration unit

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Solution Overview

Problem

Transport refrigeration units are prone to thermal events, such as engine compartment fires, despite insulation, due to high temperatures from engine operation and exhaust after-treatment components, leading to potential mechanical and financial damages.

Innovation Solution

A thermal event detection system comprising a safety controller and a linear heat detector, which changes resistance upon exposure to a threshold temperature, triggering actions like shutting off fuel supply or notifying an on-board diagnostic, to mitigate thermal risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If complete thermal insulation is implemented to protect engine compartment components, then component protection is improved, but thermal event detection capability deteriorates

Engineering Contradiction:

Improvecomponent protectionVSAvoidthermal event detection

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The thermal insulation system is segmented by introducing detection channels within the insulation structure. Linear heat detectors are embedded at specific locations within the insulation layers, creating segmented monitoring zones that allow thermal event detection without compromising overall insulation integrity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Linear heat detectors serve as intermediary elements between the thermal insulation system and the external environment. These detectors are positioned within the insulation to sense thermal events internally, acting as mediators that provide detection capability without disrupting the insulation's protective function.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If high temperatures are maintained in exhaust after-treatment components, then emission control performance is improved, but thermal event risk increases

Engineering Contradiction:

Improveemission control performanceVSAvoidthermal event risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The linear heat detection system performs preliminary detection of thermal conditions in exhaust after-treatment components before thermal events occur. By monitoring temperature thresholds within the insulation, the system provides early warning that allows preventive actions to be taken, maintaining emission control performance while reducing thermal event risk.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The detection system provides continuous feedback on thermal conditions within the engine compartment insulation. This feedback mechanism allows the system to monitor high-temperature zones around exhaust components and trigger appropriate responses, enabling safe operation at high temperatures while detecting thermal event risks.

Inventive Principle:

Principle #23Feedback

3Measurement precision

If linear heat detectors are embedded within thermal insulation, then thermal event detection precision is improved, but device complexity increases

Engineering Contradiction:

Improvethermal event detection precisionVSAvoiddetection system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Linear heat detectors are implemented as thin, flexible sensing elements that can be easily embedded within thermal insulation layers. This approach maintains detection precision by placing sensors close to potential thermal events while minimizing the added complexity through the use of simple, flexible detector elements rather than complex rigid structures.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The linear heat detectors operate by detecting changes in electrical resistance in response to temperature changes within the insulation. This parameter-based detection method provides precise thermal event detection through simple electrical measurements, avoiding the need for complex mechanical or optical detection systems.

Inventive Principle:

Principle #35Parameter changes

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

Effectively detects thermal events and initiates safety actions, reducing the risk of mechanical and financial damage by promptly addressing overheating conditions in transport refrigeration units.

Implementation Method 1

the linear heat detector is operative to create, subsequent to being exposed to a temperature greater than or equal to a threshold temperature, a change in resistance along at least a portion of the linear heat detector

Methodology Applied

Scientific EffectThermal event detection through resistance change: Thermal Expansion

Data Source

PatentUS10828961B2Apparatus and method for thermal event detection in a transport refrigeration unit

Publication Date: 2020.11.10 CARRIER CORP

AI summary

A system and method for thermal event detection in a transport refrigeration unit that includes a safety controller (302) communicatively coupled to a linear heat detector (304) affixed to a hood (202) of the transport refrigeration unit. The safety controller is configured to detect a change in resistance of the linear heat detector and initiate an action like shutting off the fuel supply to an internal combustion engine inside the compartment. The linear heat detector is operative to create, subsequent to being exposed to a temperature greater than or equal to a threshold temperature in the interior compartment (208), a change in resistance along at least a portion of the linear heat detector. The safety controller is further configured to initiate an action upon having detected the change in resistance.