Integrated Boost Pump Generator Stage for Decoupled Aircraft Fuel Pump Speeds
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Solution Overview
Problem
Aircraft fuel systems face challenges in efficiently operating boost pumps and main pumps at their optimal speeds without the added cost and weight of additional gear centerlines and housings.
Innovation Solution
Integrating boost pumps with generators or permanent magnet machines, which operate independently of main pumps, allowing for decoupled rotational speeds and utilizing a portion of the fuel flow for cooling and lubrication, thereby eliminating the need for separate drive pads and dedicated oil systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an additional gear centerline and housing are added to operate boost pumps and main pumps at different speeds, then the pumps can operate at their optimal respective speeds, but the system cost and weight increase
Solution Approach 1:
The patent combines the boost pump and main pump onto a single gear centerline, eliminating the need for a second accessory drive pad and its associated housing. This merging of functions reduces system weight and complexity while maintaining the ability to operate both pumps at optimal speeds through a single integrated drive system.
2Productivity
If an additional gear centerline and housing are added to operate boost pumps and main pumps at different speeds, then the pumps can operate at their optimal respective speeds, but the system cost increases
Solution Approach 1:
The patent integrates the boost pump and main pump drive functions into a single gear centerline assembly, reducing the number of separate components that need to be manufactured and assembled. This consolidation lowers manufacturing costs by eliminating redundant housings and simplifying the overall gear system architecture.
3Adaptability or versatility
If a separate drive pad is used for boost pumps, then independent speed control is achieved, but device complexity increases
Solution Approach 1:
The single gear centerline is designed to serve multiple functions: driving both the boost pump and main pump at different speeds, providing gear protection, and facilitating oil circulation. This multi-functional design achieves independent speed control without the complexity of separate drive pads and housings.
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 integration reduces system weight and cost while ensuring optimal pump operation and redundancy, with improved efficiency and reduced size and complexity.
Implementation Method 1
at least one permanent magnet machine collocated with and operatively connected to the boost pump for driving the boost pump
Implementation Method 2
using a tapped fuel flow for cooling and lubrication
Data Source
AI summary
An aircraft fuel system includes a first integrated boost stage having a boost pump configured to receive a fuel flow from a fuel tank via a boost supply line, at least one generator collocated with and operatively connected to the boost pump for driving the boost pump, and a tap fluidly connecting the boost pump and the at least one generator for selectively delivering an amount of the fuel flow to the at least one generator. The fuel system further includes a gearbox operatively connected to the at least one generator, and a main stage downstream of the boost stage and operatively connected to the gearbox. The main stage includes a main pump configured to receive the fuel flow from the boost pump along a main supply line, and a filter disposed along the main supply line upstream of the main pump for filtering the fuel flow.