Cooling Apparatus Error Detection via Thermal Resistance

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Solution Overview

Problem

Existing error detection systems for cooling apparatuses in moving vehicles, such as railroad vehicles, fail to accurately diagnose performance deterioration and aging due to transient changes in thermal load, leading to potential missed maintenance opportunities and increased risk of thermal runaway.

Innovation Solution

An error detection system that utilizes temperature and current sensors to estimate thermal resistance, storing time-series data and calculating predictive information on cooling apparatus performance, with a communication system to transmit data for remote analysis and maintenance notification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If temperature sensors are mounted on two portions of a cooler to detect errors, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveerror detection accuracyVSAvoidsensor mounting complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the temperature measurement function from direct cooler contact and relocates it to the heat generator housing, where a single temperature sensor can indirectly monitor cooler performance through thermal resistance calculations, thereby reducing sensor quantity and system complexity while maintaining detection capability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces thermal resistance as an intermediary parameter that connects the temperature measurements to cooler performance assessment. By calculating thermal resistance between the heat generator and ambient air, the system can infer cooler effectiveness without requiring direct temperature sensors on the cooler itself

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If error detection is based on thermally steady state presumption, then device complexity is reduced, but measurement precision deteriorates due to transient thermal load changes

Engineering Contradiction:
Improvedetection system simplicityVSAvoidperformance deterioration diagnosis accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary calculations of thermal resistance and stores it in a database before actual error detection occurs. This pre-established thermal resistance baseline enables accurate comparison with current measurements, allowing precise detection of performance deterioration even during transient thermal conditions without complicating the real-time detection system

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism where current thermal resistance measurements are continuously compared against stored baseline values. This feedback loop enables the system to detect deviations indicating cooler performance deterioration, maintaining high measurement precision while keeping the detection logic relatively simple through systematic data comparison

Inventive Principle:
Principle #23Feedback

3Reliability

If thermal resistance calculation and predictive information storage are implemented, then reliability of early diagnosis is improved, but loss of time for data processing increases

Engineering Contradiction:
Improveearly diagnosis accuracyVSAvoiddata processing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent performs preliminary calculation and storage of thermal resistance values in a database during normal operation phases. By pre-processing and storing this critical diagnostic data, the system minimizes real-time computation requirements, enabling rapid and reliable early diagnosis when performance deterioration is detected without significant time loss during critical monitoring moments

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent dynamically adapts the data processing intensity based on operational conditions. During steady-state operation, comprehensive thermal resistance calculations are performed and stored. During transient or critical phases, the system relies on pre-stored data and simpler comparison logic, thereby maintaining high diagnostic reliability while minimizing time loss through adaptive processing strategies

Inventive Principle:
Principle #15Dynamics

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

Enables early and accurate diagnosis of cooling apparatus performance deterioration and aging, ensuring timely maintenance and reducing the risk of thermal runaway by accurately estimating thermal resistance and monitoring heat exchange performance.

Implementation Method 1

a first temperature sensor that detects a temperature of the cooling apparatus and a second temperature sensor that detects an ambient air temperature

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

the cooling apparatus... that dissipates heat generated from a power converter

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

a cooling apparatus... that dissipates heat generated from a power converter

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 4

dissipates heat generated from a power converter for a railroad vehicle

Methodology Applied
Scientific EffectThermal convection: Convection

Data Source

PatentEP2950626B1Error detection system for cooling apparatus
Publication Date: 2019.02.20 HITACHI LTD
  • EP2950626B1 patent drawingFigure 1
  • EP2950626B1 patent drawingFigure 2
  • EP2950626B1 patent drawingFigure 3

AI summary

Disclosed is an error detection system for detecting an error in a cooling apparatus (101) mounted in a power converter (4) that drives, for example, a motor (not shown). The error detection system includes a first temperature sensor, a second temperature sensor, and a current sensor. The first temperature sensor measures a representative temperature (Tb) of the cooling apparatus. The second temperature sensor measures an ambient air temperature (Ta). The current sensor measures an input/output current (Im) controlled by the power converter. The error detection system receives measured signals sent from the first temperature sensor, the second temperature sensor, and the current sensor and thereby estimates the performance of the cooling apparatus.