Aircraft Engine Idle Speed Control for Compressor Surge Prevention

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Solution Overview

Problem

Aircraft engines face challenges in managing idle speed and power draw, particularly with high bypass ratio engines, which can lead to compressor surge and increased fuel consumption, while also dealing with rising electrical power requirements that exacerbate these issues.

Innovation Solution

A method and system that dynamically adjust idle speed and power draw by determining current and future power requirements, using data from engines and auxiliary sources, to optimize power distribution and reduce idle thrust, incorporating power management and pneumatic draw control units to adapt to consumer system needs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the idle speed is increased to prevent compressor surge, then the engine can provide enough power, but the engine thrust increases which leads to increased fuel consumption and wear on brakes

Engineering Contradiction:

Improvecompressor surge preventionVSAvoidfuel consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts the idle speed of the engine based on real-time power requirements of aircraft systems. Instead of maintaining a fixed high idle speed to prevent compressor surge, the control system continuously monitors power demand and adjusts the idle speed accordingly, allowing the engine to operate at the minimum necessary speed to prevent surge while minimizing fuel consumption.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention implements a feedback control mechanism where the actual power consumption of aircraft systems is monitored and fed back to the engine control unit. This feedback loop enables the system to adjust the idle speed in response to changing power requirements, ensuring optimal balance between preventing compressor surge and minimizing fuel consumption.

Inventive Principle:

Principle #23Feedback

2Use of energy by moving object

If the idle speed is limited by minimizing power drawn from the engine, then fuel consumption is reduced, but the aircraft systems cannot operate optimally

Engineering Contradiction:

Improvefuel consumptionVSAvoidaircraft systems operation

Core Design Contradiction:

Use of energy by moving objectVSProductivity

Solution Approach 1:

The system dynamically adjusts the idle speed based on the actual power requirements of aircraft systems. When systems require more power, the idle speed is increased accordingly; when power requirements are lower, the idle speed is reduced. This dynamic adjustment ensures that aircraft systems receive the power they need to operate optimally while minimizing fuel consumption when high power is not required.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the operating parameters of the engine (idle speed) based on the power requirements of aircraft systems. By adjusting the idle speed parameter in response to changing system demands, the system ensures optimal operation of aircraft systems while maintaining fuel efficiency.

Inventive Principle:

Principle #35Parameter changes

3Power

If the size of the engine body is increased to meet power draw requirements, then power availability is improved, but fuel consumption increases due to not optimizing the engine

Engineering Contradiction:

Improvepower draw capacityVSAvoidfuel consumption

Core Design Contradiction:

PowerVSUse of energy by moving object

Solution Approach 1:

Instead of increasing the physical size of the engine to provide more power, the invention dynamically adjusts the operating parameters (idle speed) of the existing engine to meet power requirements. This approach allows the engine to provide sufficient power when needed while maintaining optimal fuel efficiency during normal operation, avoiding the fuel consumption penalty associated with larger, less efficient engines.

Inventive Principle:

Principle #15Dynamics

4Use of energy by moving object

If the power draw capacity is reduced to optimize fuel consumption, then fuel efficiency is improved, but the risk of compressor surge increases

Engineering Contradiction:

Improvefuel consumptionVSAvoidcompressor surge risk

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The system implements continuous monitoring of engine operation parameters and power requirements, with feedback control that adjusts the idle speed to maintain safe operation above the compressor surge threshold. This feedback mechanism ensures that the engine operates at the minimum safe idle speed to prevent surge while minimizing fuel consumption, rather than using a fixed conservative margin.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11840350B2Method and system for controlling idle speed and drawing of power generated by an aircraft engine

Publication Date: 2023.12.12 AIRBUS (SAS)

AI summary

A system for controlling idle speed and power draw includes a determination unit configured to determine a current available power value, a determination unit configured to determine a current power consumption value, a determination unit configured to determine a future power requirement variation value, a computation unit configured to calculate a future estimated total power requirement value, a computation unit configured to calculate a future estimated available power value, an optimization unit configured to determine an optimization result by comparing the estimated total power requirement value with a power value associated with an optimization criterion and a controller configured to send an order to adapt an idle speed of the engine, an order to adapt the estimated total power requirement or no order as a function of the optimization result.