Standby Engine Power Profiles for Asymmetric Regime Exit

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Solution Overview

Problem

Existing multi-engine systems, such as those in rotorcraft, face challenges in efficiently transitioning from an asymmetric operating regime (AOR) due to rapid power changes causing thermal stresses and reducing engine durability.

Innovation Solution

A controller-based system that manages engine power profiles by detecting exit conditions with varying priority levels, implementing gradual or rapid power transitions based on priority, and using rate limiters to smooth engine power changes, ensuring engine safety and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If the standby engine transitions rapidly from low-power to high-power mode, then the power recovery time is reduced, but thermal stresses increase and engine durability decreases

Engineering Contradiction:
Improvepower recovery timeVSAvoidengine durability
Core Design Contradiction:
Loss of timeVSStrength

Solution Approach 1:

The system dynamically adjusts the exit rate parameter in real-time based on detected exit conditions. The controller modifies the power transition profile from the standby engine by selecting different exit rates (e.g., rapid exit, moderate exit, slow exit) according to the priority level of detected conditions, making the transition process adaptive rather than fixed

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The controller continuously monitors and detects exit conditions with priority levels before initiating the power transition. By identifying high-priority conditions in advance, the system can prepare and execute the appropriate exit rate profile, ensuring rapid response when critical conditions are detected while maintaining engine safety

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If multiple exit conditions with different priority levels are detected during power transition, then the system can respond to varying operational needs, but the control complexity increases

Engineering Contradiction:
Improveresponse to varying operational needsVSAvoidcontrol complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The controller continuously monitors exit conditions throughout the entire power transition process, not just at the beginning. This continuous detection ensures that if new conditions arise or condition priorities change during the transition, the system can respond appropriately by adjusting the exit rate profile mid-transition, maintaining adaptability throughout the process

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The controller acts as an intermediary that manages the complexity of multiple exit conditions by implementing a priority-based decision hierarchy. Rather than allowing all conditions to interact equally, the controller filters and processes conditions through a structured priority system, selecting the highest-priority condition to dictate the exit rate profile, thereby simplifying the control logic

Inventive Principle:
Principle #24Intermediary (Mediator)

3Loss of energy

If the standby engine operates in low-power mode during asymmetric operating regime, then fuel efficiency is improved, but the engine must be capable of rapid power increase when needed

Engineering Contradiction:
Improvefuel efficiencyVSAvoidpower increase capability
Core Design Contradiction:
Loss of energyVSPower

Solution Approach 1:

The system implements periodic monitoring of exit conditions during the standby engine's low-power operation. By continuously detecting operational parameters and exit conditions at regular intervals, the system maintains readiness to transition to high-power mode when needed, balancing fuel efficiency during normal operation with the capability for rapid power increase when conditions change

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP4685053A1System and method for exiting an asymmetric operating regime
Publication Date: 2026.01.28 PRATT & WHITNEY CANADA CORP
  • EP4685053A1 patent drawingFigure 1
  • EP4685053A1 patent drawingFigure 2
  • EP4685053A1 patent drawingFigure 3

AI summary

A system (105) comprises a first engine (102) configured to have an active mode of operation and a standby mode of operation and a second engine (104) configured to have the active mode of operation and the standby mode of operation. The controller (210) is configured to detect a first exit condition having a first priority level, implement a first engine power profile responsive to a detection of a first exit condition having the first priority level for the second engine (104) in a standby mode of operation, detect a second exit condition having a second priority level for the second engine (104) during implementation of the first engine power profile, maintain the first engine power profile responsive to a determination that the second priority level is not greater than the first priority level, and implement a second engine power profile responsive to a determination that the second priority level is greater than the first priority level.