Variable Displacement Fuel Pump Control for Aerial Refueling Pressure
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Solution Overview
Problem
Aerial refueling systems face inefficiencies due to wasted energy and potential fuel heating caused by pressure differences when refueling aircraft, as the fuel delivery pressure exceeds design standards, leading to suboptimal refueling processes.
Innovation Solution
A fuel pump system driven by a variable displacement motor, controlled by a drive system controller, which maintains a predetermined maximum inlet pressure and adjusts fuel flow rates to prevent pressure exceedance, incorporating modes for flow control, pressure regulation, and priority responses to hydraulic pressure changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the refueling system maintains a target flow rate using a fixed displacement fuel pump, then the fuel delivery pressure may exceed design standards when back pressure increases, but reducing the flow rate creates wasted energy and pressure difference at the reception coupling
Solution Approach 1:
The patent applies a variable displacement fuel pump that dynamically adjusts its displacement based on real-time pressure feedback from the reception coupling. The pump controller modulates the pump's output to maintain fuel delivery pressure within design standards, preventing both pressure exceedance and energy waste by matching supply to actual demand conditions throughout the refueling operation.
Solution Approach 2:
The patent implements a closed-loop feedback control system where pressure sensors at the reception coupling continuously monitor fuel delivery pressure and provide feedback to the pump controller. This feedback mechanism enables the variable displacement pump to automatically adjust its output, maintaining pressure within specified limits and eliminating the energy waste associated with fixed displacement pumps operating against varying back pressure.
2Reliability
If the reception coupling partially closes to reduce flow rate when back pressure increases, then fuel delivery pressure is regulated, but the refueling system continues to seek target flow rate creating pressure difference and heat
Solution Approach 1:
The patent employs a preliminary action principle by proactively adjusting the variable displacement pump's output in response to pressure feedback before excessive pressure buildup occurs. The pump controller receives real-time pressure data and preemptively modulates pump displacement to prevent pressure exceedance and associated fuel heating, rather than reacting after the problem manifests.
Solution Approach 2:
The patent changes the operating parameters of the fuel pump from fixed to variable displacement, enabling dynamic adjustment of pump output based on actual system conditions. This parameter change allows the system to maintain pressure within design standards while minimizing pressure differences that cause fuel heating, directly addressing the thermal issues caused by fixed displacement operation.
3Productivity
If a fixed displacement fuel pump is used to maintain target flow rate, then refueling speed is maintained, but energy is wasted when back pressure results in pressure exceeding design standards
Solution Approach 1:
The variable displacement fuel pump performs self-service by automatically adjusting its own displacement based on feedback from pressure sensors in the refueling system. The pump controller monitors pressure conditions and modulates pump output accordingly, enabling the system to maintain both refueling productivity and energy efficiency without external intervention or manual adjustment.
Solution Approach 2:
The patent implements feedback control where pressure sensors continuously monitor the refueling system and provide real-time data to the variable displacement pump controller. This feedback enables the pump to dynamically adjust its displacement to maintain optimal pressure, preventing energy waste while sustaining refueling productivity throughout the operation.
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
The system ensures efficient fuel delivery by maintaining optimal flow rates and pressures, reducing energy waste and enhancing the refueling process, while prioritizing hydraulic pressure demands to maintain system functionality.
Implementation Method 1
a variable displacement motor operable to be driven by a hydraulic fluid pressure
Data Source
AI summary
A fuel pump system for an aerial refueling system including: a variable displacement motor operable to be driven by a hydraulic fluid pressure; a fuel pump operable to be driven by the variable displacement motor; and a drive system controller (DSC) connected to the variable displacement motor, wherein the DSC is operable to direct an operation of the fuel pump in modes comprising: a flow control mode operable to maintain an output fuel flow rate from the fuel pump to a predetermined maximum inlet pressure at a reception coupling for a receiver aircraft; a fuel pressure control mode operable to regulate the output fuel flow rate to not exceed the predetermined maximum inlet pressure; and a priority mode operable to reduce the output fuel flow rate in response to a decrease in the hydraulic pressure. Also a method of refueling a receiver aircraft.