Integrated Air Cycle Machine Layout for Compact Cabin Air Compression

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Solution Overview

Problem

Traditional aircraft environmental control systems (ECS) face challenges with complex ducting and valve arrangements in air cycle machines (ACM) that result in increased weight and size, inefficiencies, and spatial constraints, particularly when integrating an integrated cabin air compressor (CAC).

Innovation Solution

An air cycle machine (ACM) with axial rotors and an integrated cabin air compressor (CAC) is designed with a unified shell and shaft configuration, featuring a motor, compressor, and turbine, where the shaft provides backflow for motor cooling and airflow dynamics are optimized through conical and cylindrical shell portions, and the shell is formed of two unitary half-shells connected by hinges and fasteners.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional ACM configurations use complex ducting and valve arrangements between heat exchanger and rotor stages, then the system can achieve proper airflow conditioning, but the weight and size of the system increases considerably

Engineering Contradiction:

Improveairflow conditioningVSAvoidsystem weight

Core Design Contradiction:

ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent combines the heat exchanger, compressor, turbine, and associated ducting into a single integrated ACM assembly. The compressor and turbine are mounted on opposite ends of a common shaft within the same housing, eliminating the need for separate ducting arrangements between independently mounted components. This merging reduces overall system weight while maintaining proper airflow conditioning through the integrated design.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

Engineering Contradiction:

Improveairflow conditioningVSAvoidsystem volume

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent employs a nested arrangement where the compressor and turbine stages are housed within a common ACM housing. The intermediate heat exchanger is integrated within the same housing, with airflow passages nested through the structure. This nesting of components within a single compact housing reduces the overall system volume compared to separate mounted components with external ducting.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Adaptability or versatility

If separate ACM and CAC systems are used in the ECS, then each system can be independently optimized, but inefficiencies are separately introduced into the ECS by each component

Engineering Contradiction:

Improveindependent optimizationVSAvoidsystem efficiency

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent designs the ACM to serve multiple functions within the ECS. The ACM can operate as a primary air cycle machine for cabin pressurization and temperature control, while also functioning as a cabin air compressor (CAC) when the aircraft engines are running. The integrated design allows the same compressor stages to provide both ACM and CAC functions, eliminating energy losses associated with separate independent systems and improving overall ECS efficiency.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

This configuration reduces inefficiencies and weight, minimizes drag, and simplifies maintenance by integrating the ACM and CAC into a unified system, enhancing airflow dynamics and reducing spatial requirements.

Implementation Method 1

the shaft provides for backflow from the turbine to the compressor, via the shaft inlet and outlet, for cooling of the motor

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

a compressor coupled to the front end of the motor; the compressor is an axial compressor

Methodology Applied

Scientific EffectCompression: Compression

Implementation Method 3

a turbine coupled to the aft end of the motor; the turbine is an axial turbine; the turbine includes a turbine high pressure stage and a turbine low pressure stage

Methodology Applied

Scientific EffectTurbine expansion: Turbine

Data Source

PatentUS20260043410A1Air cycle machine with axial rotors and integrated cabin air compressor

Publication Date: 2026.02.12 HAMILTON SUNDSTRAND CORP

AI summary

An ACM having a motor with front and aft ends; a compressor coupled to the front end; a turbine coupled to the aft end; a shell having a shell front part that surrounds the compressor and defines a shell inlet, a shell aft part that surrounds the turbine and defines a shell outlet, and a shell middle part that surrounds the motor; an outer flow passage is defined within the shell, surrounding the compressor, the motor and the turbine; a shaft extends between the compressor and turbine to define a shaft front end coupled to the compressor, and a shaft aft end coupled to the turbine, and the motor includes a rotor that is mounted to the shaft.