Aircraft Fuel System Pump Integration

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Solution Overview

Problem

Conventional aircraft fuel systems require multiple pumps and filters, leading to complexity, weight, and inefficiency, as they are designed without considering engine integration, resulting in suboptimal performance and reliability.

Innovation Solution

A fuel system utilizing three-phase DC electric variable speed airframe pumps to provide main stage boost pressure, eliminating the need for engine boost pumps and upstream filters, with centrifugal pumps driven by the engine and integrated with a heat exchanger and cross-feed valves for efficient fuel management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional airframe level fuel systems are designed without engine integration, then fuel pumping can be simplified, but system complexity and weight increase due to requiring separate boost pumps and gear pumps for each engine

Engineering Contradiction:
Improvefuel system complexityVSAvoidfuel system reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent merges the airframe fuel pump and engine fuel pump into a single integrated pump unit. The airframe fuel pump provides both airframe fuel delivery and engine fuel delivery functions, eliminating the need for separate engine boost pumps and gear pumps. This integration reduces system complexity while maintaining reliable fuel supply to both airframe systems and engine combustors.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The airframe fuel pump is designed with multi-functionality to serve multiple purposes: it provides fuel to the airframe fuel system and simultaneously provides fuel to the engine. The pump includes separate outlets for airframe fuel delivery and engine fuel delivery, allowing a single pump to replace what would traditionally require multiple separate pumps, thereby reducing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If multiple pumps and filters are used in conventional fuel systems, then fuel delivery reliability is maintained, but system weight increases

Engineering Contradiction:
Improvefuel delivery reliabilityVSAvoidfuel system weight
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent combines multiple pump functions into a single airframe fuel pump unit that provides both airframe fuel delivery and engine fuel delivery. This eliminates the need for separate engine boost pumps and gear pumps, significantly reducing the total weight of the fuel system while maintaining reliable fuel delivery through the integrated pump's multiple outlets.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts and eliminates redundant components from the conventional fuel system. By removing the separate engine boost pump and gear pump, and the associated upstream filters, the system achieves weight reduction while the integrated pump maintains fuel delivery reliability through its multi-functional design with separate outlets for different fuel destinations.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If engine boost pump and upstream filters are included, then fuel filtering reliability is improved, but device complexity and weight increase

Engineering Contradiction:
Improvefuel filtering reliabilityVSAvoidfuel system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the engine boost pump and its associated upstream filters from the conventional fuel system architecture. The integrated airframe fuel pump provides fuel directly to the engine without requiring these intermediate components, thereby reducing system complexity and weight while maintaining fuel delivery reliability through the pump's direct engine outlet.

Inventive Principle:
Principle #2Taking out (Extraction)

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

This design reduces system complexity and weight, enhances reliability, and improves fuel efficiency by eliminating redundant components and optimizing pump sizing for cruise conditions, while maintaining high pressure for reliable engine operation.

Implementation Method 1

The main stage boost pressure is about 1723.69 kPa (250 psi). Each airframe fuel pump can be a three phase DC electric variable speed pump

Methodology Applied
Scientific EffectPressure generation: Pressure Increase

Implementation Method 2

The one or more engine fuel pumps can be a centrifugal pump mechanically connected to the engine to be driven by the engine

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 3

The system can include an engine heat exchanger disposed between the airframe fuel pump and the engine fuel pump

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP3670866B1Fuel systems for aircraft and methods of pressurizing fuel
Publication Date: 2024.09.11 HAMILTON SUNDSTRAND CORP
  • EP3670866B1 patent drawingFigure 1
  • EP3670866B1 patent drawingFigure 2

AI summary

A fuel system (100) for an aircraft can include one or more airframe fuel lines (101) configured to transfer fuel from one or more fuel tanks to an engine, one or more engine fuel pumps (109) in fluid communication with the one or more airframe fuel lines and configured to pressurize fuel from a main stage boost pressure to a combustor pressure to be injected into a combustor of an engine, one or more airframe fuel pumps (107) configured to pressurize fuel within the one or more airframe fuel lines to the main stage boost pressure used by the engine fuel pump. For example, the main stage boost pressure can be about 250 psi.