Multi-Engine Aircraft Bleed Air Coupling for Low-Power Operations

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Solution Overview

Problem

Existing multi-engine aircraft systems, particularly in helicopters, face challenges in supplying adequate flowrate and pressure of bleed air during low-power or standby engine operations, as conventional systems may not be self-sufficient in such conditions.

Innovation Solution

Implementing an asymmetric operating regime where one engine operates in high-power active mode and the other in low-power standby mode, with a control system managing fuel flow and utilizing a control valve to connect or disconnect bleed air systems between engines, and optionally using an external compressed air source to ensure self-sufficiency of both systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If one engine operates in low-power standby mode, then fuel efficiency is improved, but bleed air supply capability deteriorates

Engineering Contradiction:
Improvefuel efficiencyVSAvoidbleed air supply capability
Core Design Contradiction:
Use of energy by moving objectVSQuantity of substance

Solution Approach 1:

The patent merges the bleed air systems of two engines by connecting them through a common manifold and control valve. When one engine is in standby mode, the other engine's bleed air system is coupled to the standby engine's system, allowing the active engine to supply bleed air to both engines. This combining approach ensures that the standby engine receives adequate bleed air without requiring its own compressor to operate at full capacity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces a control valve as an intermediary component that manages the connection between the two engine bleed air systems. The control valve selectively opens or closes to regulate bleed air flow from the active engine to the standby engine, ensuring proper bleed air supply while maintaining the fuel efficiency benefits of asymmetric operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Use of energy by moving object

If asymmetric operation is implemented, then fuel efficiency is improved, but system reliability deteriorates

Engineering Contradiction:
Improvefuel efficiencyVSAvoidsystem reliability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent incorporates a control system that continuously monitors engine operating conditions and automatically adjusts the control valve position to maintain reliable bleed air supply. The feedback mechanism ensures that when one engine is in standby mode, the system detects and responds by activating the other engine's bleed air system, thereby maintaining system reliability despite asymmetric operation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent prepares for potential reliability issues by pre-configuring the bleed air systems with a control valve and common manifold arrangement. This beforehand arrangement ensures that if one engine fails or enters standby mode, the other engine can immediately compensate by supplying bleed air to both systems, preventing service disruption and maintaining reliability.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Device complexity

If conventional bleed air systems are used, then system simplicity is maintained, but adaptability to low-power operations deteriorates

Engineering Contradiction:
Improvesystem simplicityVSAvoidadaptability to low-power operations
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamic control capability to the bleed air system through a control valve that can adjust its position based on operating conditions. This dynamic element allows the system to adapt to low-power operations by regulating bleed air flow from the active engine to the standby engine, enabling the system to handle asymmetric operation modes while maintaining reasonable structural simplicity.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3744636B1Air system of multi-engine aircraft
Publication Date: 2025.07.16 PRATT & WHITNEY CANADA CORP
  • EP3744636B1 patent drawingFigure 1
  • EP3744636B1 patent drawingFigure 2
  • EP3744636B1 patent drawingFigure 3

AI summary

A method of operating an engine of an aircraft, the engine having a bleed air system. The method includes in flight, directing pressurized air from a source of pressurized air external to the engine to the bleed air system of the engine. An aircraft, comprising a first engine having a bleed air system, a second engine having a bleed air system, and a source of pressurized air that is external to the first and/or the second engine, the source of pressurized air being selectively fluidly connectable to the bleed air system of the first and/or the second engine, is also disclosed.