Aircraft Cabin Air Compressor Liquid Cooling Passage

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Solution Overview

Problem

Aircraft cabin air compressors (CACs) face inefficiencies in cooling, as air-cooled electric motors may not adequately manage temperature, leading to potential overheating and reduced system performance.

Innovation Solution

A liquid-cooled supplemental passage is integrated into the CAC case, surrounding critical components like motors and bearings, to enhance cooling efficiency by directing a liquid cooling medium through the compressor, thereby reducing component temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If air-cooled electric motors are used in the CAC, then the system structure is simple, but the cooling efficiency is insufficient leading to overheating

Engineering Contradiction:
Improvecomponent temperatureVSAvoidcooling system complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent introduces a liquid cooling system using hydraulic principles to circulate cooling liquid through passages in the motor housing and bearing chambers. This liquid-cooled approach replaces the insufficient air-cooling system, effectively removing heat from the motor and bearing components while managing the increased system complexity through integrated cooling passages.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The cooling system is segmented into distinct cooling passages: motor cooling passages formed in the motor housing and bearing cooling passages in the bearing chambers. This segmentation allows targeted cooling of different hot spots (motor windings and bearing surfaces) independently, improving overall cooling efficiency while maintaining manageable system complexity.

Inventive Principle:
Principle #1Segmentation

2Reliability

If cooling passages are added to cool the motor, then the cooling efficiency improves, but the device complexity increases

Engineering Contradiction:
Improvesystem reliabilityVSAvoidcooling passage complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the cooling passages directly into the motor housing structure and bearing chamber walls. The motor housing itself forms the cooling passages, and the bearing chambers incorporate cooling channels in their walls. This integration combines the structural components with the cooling function, improving reliability through effective cooling while minimizing additional complexity by using existing structural elements.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The motor housing serves dual functions: it provides structural support for the motor assembly and simultaneously acts as a cooling manifold with integrated cooling passages. The bearing chambers also serve both as structural elements and as cooling channels. This multi-functionality improves system reliability through effective cooling while reducing overall device complexity by eliminating separate cooling components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Duration of action of stationary object

If cooling passages are added to cool the bearings, then the bearing lifespan is extended, but the device complexity increases

Engineering Contradiction:
Improvebearing lifespanVSAvoidcooling system complexity
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The bearing cooling passages are merged directly into the bearing chamber walls. The cooling liquid flows through channels formed in the bearing chamber structure, directly cooling the bearing surfaces where they are located. This integration extends bearing lifespan through effective cooling while minimizing complexity by using the bearing chamber structure itself as the cooling passage.

Inventive Principle:
Principle #5Merging (Combining)

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 implementation of a liquid-cooled supplemental passage effectively cools the motor and bearing components, prolonging their lifespan and improving the reliability and performance of the CAC by maintaining optimal operating temperatures.

Implementation Method 1

The supplemental cooling passage is configured to direct a supplemental cooling medium through it... effectively cools the motor and bearing components

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

directing a liquid cooling medium through the compressor, thereby reducing component temperatures

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP4019784B1Cabin air compressor with liquid cooled passage formed in the case
Publication Date: 2024.11.27 HAMILTON SUNDSTRAND CORP
  • EP4019784B1 patent drawingFigure 1
  • EP4019784B1 patent drawingFigure 2

AI summary

Disclosed is a cabin air compressor (CAC) of an aircraft environmental control system, the CAC having: a CAC case (110) defining a forward end and an aft end axially spaced apart axially from the forward end, wherein the forward end defines a compressor inlet; and a supplemental cooling passage (500) defined by the CAC case (110), wherein the supplemental cooling passage (500) is configured to direct a supplemental cooling medium through it.