Dual Pump Fuel Delivery System for Aircraft
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Solution Overview
Problem
Aircraft fuel delivery systems face inefficiencies as fixed displacement pumps are sized for peak demand, leading to fuel bypass during non-peak conditions, which does not accurately match varying fuel demands throughout different flight phases, resulting in suboptimal fuel consumption.
Innovation Solution
A dual pump fuel delivery system comprising a fixed displacement pump and a variable displacement pump, with a pressure regulating valve and electro-hydraulic servo valves, that adjusts fuel output to match changing fuel demands by controlling bypass flow, ensuring optimal fuel delivery and consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed displacement pump is sized to deliver peak flow demand, then the fuel demand is satisfied during takeoff, but fuel is bypassed during non-peak conditions resulting in suboptimal fuel consumption
Solution Approach 1:
The fuel delivery system is segmented into two separate pumps: a fixed displacement pump for base fuel delivery and a variable displacement pump for additional fuel delivery when needed. This segmentation allows each pump to operate efficiently in its optimal range, with the variable displacement pump supplementing the fixed displacement pump only when peak demand requires it, thereby eliminating unnecessary fuel bypass and improving overall fuel consumption efficiency.
Solution Approach 2:
The variable displacement pump introduces dynamic adjustment capability to the previously static fixed displacement pump system. The variable displacement pump can adjust its output based on real-time fuel demand conditions, delivering additional fuel during peak demand (takeoff) and reducing or stopping delivery during non-peak conditions, thus eliminating the energy waste associated with bypassing excess fuel.
2Device complexity
If a fixed displacement pump is used, then the system is simple, but it cannot accurately match varying fuel demands throughout different flight phases
Solution Approach 1:
The fuel delivery function is segmented between a fixed displacement pump that provides steady base delivery and a variable displacement pump that provides adjustable supplemental delivery. This segmentation enables the system to maintain simplicity through the fixed displacement pump while gaining adaptability through the variable displacement pump's ability to match varying fuel demands across different flight phases.
Solution Approach 2:
The dual pump system creates a multi-functional fuel delivery capability where the fixed displacement pump handles baseline fuel delivery across all flight phases, while the variable displacement pump provides adaptive supplementation during specific phases requiring higher demand. This multi-functionality allows the system to accurately match varying fuel demands without requiring a completely complex reconfiguration.
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 effectively matches fuel demand across different flight phases, reducing fuel wastage and optimizing thrust-specific fuel consumption by dynamically adjusting fuel output between fixed and variable displacement pumps.
Implementation Method 1
the control member comprises an electro-hydraulic servo valve (EHSV)
Implementation Method 2
A variable displacement fuel pump including an inlet portion and an outlet portion includes a selectively adjustable pump actuator
Data Source
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AI summary
A dual pump fuel delivery system for an aircraft includes a fixed displacement fuel pump including an inlet (30) and an outlet (34). The fixed displacement fuel pump is configured to supply a first portion of a fuel demand for the aircraft. A variable displacement fuel pump including an inlet portion and an outlet portion includes a selectively adjustable pump actuator configured to supply a second portion of the fuel demand. The second portion is variable. A fuel demand sensor (88) operates to detect a selected fuel demand. A control member (69, 71) is operatively connected to the fuel demand sensor (88) and the variable displacement fuel pump. The control member (69, 71) being configured to operate to adjust the variable displacement fuel pump to output the second portion of the fuel demand to satisfy the selected fuel demand.