Asymmetric Engine Operation for Fuel Efficiency

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing technologies lack efficient methods for managing engine operating regimes in multi-engine aircraft, particularly during cruising conditions where fuel efficiency can be improved by operating one engine at a higher regime while the other operates at a lower regime.

Innovation Solution

A method and system utilizing a Full Authority Digital Engine Control (FADEC) to monitor engine and aircraft parameters, ensuring that specific conditions are met before allowing the engines to operate asymmetrically, thereby optimizing fuel efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If both engines operate at lower regimes during cruising, then power redundancy is maintained, but fuel efficiency deteriorates

Engineering Contradiction:

Improvefuel efficiencyVSAvoidpower redundancy

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The system enables asymmetric engine operation where one engine operates at a higher regime while the other operates at a lower regime during cruising conditions. This asymmetric configuration allows the aircraft to maintain adequate power redundancy while significantly improving fuel efficiency compared to symmetric operation of both engines at lower regimes.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The system dynamically transitions between symmetric and asymmetric engine operating regimes based on flight conditions. During cruising, it dynamically shifts to asymmetric operation for fuel efficiency, while maintaining the capability to dynamically revert to symmetric operation when power redundancy requirements increase, thus adaptively balancing fuel efficiency and reliability.

Inventive Principle:

Principle #15Dynamics

2Use of energy by moving object

If one engine operates at higher regime and the other at lower regime, then fuel efficiency improves, but engine operating complexity increases

Engineering Contradiction:

Improvefuel efficiencyVSAvoidengine operating complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The FADEC system automatically manages the complexity of asymmetric engine operation without requiring pilot intervention. The system self-monitors engine parameters, determines optimal asymmetric operating regimes, and automatically controls fuel metering and engine performance, thereby improving fuel efficiency while keeping the operational interface simple for the flight crew.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system continuously monitors engine parameters including torque, inter-turbine temperature, and operational status of both engines, and uses this feedback to automatically adjust and maintain optimal asymmetric operating conditions. This closed-loop feedback control manages the complexity of asymmetric operation while delivering fuel efficiency benefits.

Inventive Principle:

Principle #23Feedback

3Loss of energy

If asymmetric engine operation is enabled, then fuel consumption reduces, but system reliability requirements increase

Engineering Contradiction:

Improvefuel consumptionVSAvoidsystem reliability requirements

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The system performs preliminary monitoring of engine parameters and operational conditions before enabling asymmetric operation. It pre-conditions the engines by ensuring both are operating normally, monitoring for faults, and verifying system readiness, thereby reducing fuel consumption through asymmetric operation while maintaining high reliability through advance preparation and validation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system maintains the capability to quickly transition from asymmetric to symmetric operation as a protective measure. By keeping the symmetric operation mode readily available and monitoring system conditions continuously, it cushions against potential reliability issues that could arise during asymmetric operation, allowing fuel efficiency improvements while managing risk.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP3693583B1System and method for operating engines of an aircraft in an asymmetric operating regime

Publication Date: 2025.05.21 PRATT & WHITNEY CANADA CORP

Figure 1A
Figure 1B
Figure 2

AI summary

Methods and systems for operating an aircraft having two or more engines (10A, 10B) are described. The method comprises receiving an engine availability confirmation when a set of engine parameters meet engine operating conditions for an asymmetric operating regime, receiving an aircraft availability confirmation when a set of aircraft parameters meet aircraft operating conditions for the asymmetric operating regime, outputting an availability message to a cockpit (210) of the aircraft in response to receiving the engine availability confirmation and the aircraft availability confirmation, receiving a pilot-initiated request to operate the engine (10A, 10B) in the asymmetric operating regime, and commanding the engines (10A, 10B) to operate in the asymmetric operating regime in response to the pilot-initiated request.