Compressor temperature control system and method

Solution Overview

Problem

Existing aircraft air cycle machine (ACM) systems require manual intervention to prevent compressor overheating, which is burdensome for crew members and can lead to inconvenient cabin pressure loss and rapid altitude descent when bleed air is shut off.

Innovation Solution

A processor-controlled system that adjusts the low limit valve based on environmental and aircraft conditions to maintain compressor outlet temperatures within safe limits, using sensors to anticipate and prevent overheating through an active feedback control loop.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual trip arrangement is used to shut off bleed air when compressor overheat is detected, then compressor damage is prevented, but crew workload increases and cabin pressure is lost requiring rapid descent

Engineering Contradiction:

Improvecompressor protectionVSAvoidcrew workload

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The control system proactively modulates the low limit valve to maintain compressor outlet temperature below the overheat threshold before damage occurs. By continuously monitoring temperature and adjusting the valve position in advance, the system prevents the need for emergency shutdown and subsequent manual intervention by the crew.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements a closed-loop feedback control mechanism where the processor continuously monitors compressor outlet temperature and adjusts the low limit valve position accordingly. This automatic feedback loop eliminates the need for manual temperature monitoring and intervention, reducing crew workload while maintaining reliable compressor protection.

Inventive Principle:

Principle #23Feedback

2Reliability

If bleed air is shut off entirely to prevent compressor overheating, then compressor damage is prevented, but cabin pressure is lost requiring rapid descent

Engineering Contradiction:

Improvecompressor protectionVSAvoidcabin pressure stability

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The control system proactively modulates the low limit valve to maintain compressor outlet temperature below the overheat threshold before damage occurs. By continuously monitoring temperature and adjusting the valve position in advance, the system prevents the need for emergency shutdown and subsequent manual intervention by the crew.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements a closed-loop feedback control mechanism where the processor continuously monitors compressor outlet temperature and adjusts the low limit valve position accordingly. This automatic feedback loop eliminates the need for manual temperature monitoring and intervention, reducing crew workload while maintaining reliable compressor protection.

Inventive Principle:

Principle #23Feedback

3Reliability

If simple trip arrangement with higher temperature set point is used when overheat is approached, then compressor damage is prevented, but manual intervention is required increasing crew workload

Engineering Contradiction:

Improvecompressor protectionVSAvoidmanual intervention requirement

Core Design Contradiction:

ReliabilityVSExtent of automation

Solution Approach 1:

The control system proactively modulates the low limit valve to maintain compressor outlet temperature below the overheat threshold before damage occurs. By continuously monitoring temperature and adjusting the valve position in advance, the system prevents the need for emergency shutdown and subsequent manual intervention by the crew.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements a closed-loop feedback control mechanism where the processor continuously monitors compressor outlet temperature and adjusts the low limit valve position accordingly. This automatic feedback loop eliminates the need for manual temperature monitoring and intervention, reducing crew workload while maintaining reliable compressor protection.

Inventive Principle:

Principle #23Feedback

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

Automatically maintains compressor outlet temperatures below the overheat threshold, reducing the risk of damage and eliminating the need for manual intervention, thereby ensuring continuous cabin air conditioning without sudden altitude changes.

Implementation Method 1

the compressor compresses the air, thus elevating the temperature

Methodology Applied

Scientific EffectAdiabatic compression: Adiabatic Heating

Implementation Method 2

the turbine is often used to expand the air resulting in a decreased air temperature

Methodology Applied

Scientific EffectAdiabatic expansion: Adiabatic Cooling

Implementation Method 3

The air then goes through a series of heat exchangers and a water extractor before entering a turbine

Methodology Applied

Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentUS10829226B2Compressor temperature control system and method

Publication Date: 2020.11.10 TEXTRON INNOVATIONS INC

AI summary

A compressor temperature control system and method for an aircraft air cycle machine is presented. The system prevents overheating of the compressor using a low limit valve positioned between a turbine outlet and a bleed air source. The low limit valve directs the air to an air cycle machine, or bypasses the machine, in regards at least in part to the air temperature measured in the cabin supply duct.