Dual Variable Displacement Pump Backup Selector
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Variable displacement pumps (VDPs) offer horsepower benefits but are not considered reliable enough for applications like single-engine aircraft, leading to reliability trade-offs in conventional systems.
Innovation Solution
A dual-pump system with a backup selector that switches between two VDPs to ensure continuous operation, utilizing a selector valve and check valves to manage fluid communication and prevent backflow, with each pump oversized by at least 40% to maintain system pressure in backup modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If variable displacement pumps (VDPs) are used to minimize horsepower required for fuel pumping, then energy efficiency is improved, but reliability deteriorates
Solution Approach 1:
The system is divided into two separate pump subsystems (first pump system with first VDP and first outlet, second pump system with second VDP and second outlet) that can operate independently. This segmentation allows each pump to be optimized for energy efficiency while the dual-configuration provides redundancy, resolving the contradiction between using VDPs for horsepower minimization and maintaining reliability.
Solution Approach 2:
The system changes the operational parameter configuration by enabling flexible switching between different pump outlets based on system needs. The ability to selectively activate either pump or both pumps simultaneously allows optimization of horsepower usage while maintaining reliable operation through redundant capability.
2Reliability
If a dual-pump system with backup capability is implemented, then reliability is improved, but device complexity increases
Solution Approach 1:
Each pump system is designed with multi-functionality to handle multiple operational modes: first pump can supply first outlet normally or backup second outlet, and second pump can supply second outlet normally or backup first outlet. This universal design reduces the need for dedicated backup components, thereby improving reliability without proportionally increasing complexity.
Solution Approach 2:
The system incorporates automatic failover capability where the backup pump automatically activates when the primary pump fails. The control system self-manages the switching between pumps without requiring complex external intervention, thereby improving reliability while keeping the control architecture relatively simple.
3Stress or pressure
If each pump is oversized by at least 40% to maintain system pressure in backup modes, then pressure stability is improved, but pump size and cost increase
Solution Approach 1:
The pumps are pre-sized with at least 40% oversizing capability during the design phase to ensure they can maintain required system pressure when operating in backup mode. This preliminary sizing action eliminates the need for complex real-time pressure adjustment mechanisms, as the physical capability is built into the pump selection from the outset.
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
Enhances fuel system reliability and cost-effectiveness by enabling VDP benefits in applications where reliability was a concern, providing pump redundancy and ensuring continuous operation with adequate pressure in both normal and backup modes.
Implementation Method 1
The backup selector can include a check valve in the first outlet line between the first pump and where the CV an SV connect to the first outlet line, configured to block backflow into the first pump in the first backup mode
Implementation Method 2
The backup selector can include a selector valve (SV) connected in fluid communication between the first outlet line and the second outlet line, wherein the SV is configured to block fluid communication between the first and second outlet lines in a normal mode
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A system includes a first pump (102) connected to an inlet line (104) and connected to a first outlet line (106) for supplying a first sub-system (112) over a first pressure schedule. A second pump (108) is connected to the inlet line and connected to a second outlet line (110) for supplying a second subsystem (114) over a second pressure schedule. A backup selector (116) is in fluid communication with the first and second outlet lines. The backup selector is configured to switch to a first backup mode to supply the first sub-system from the second pump upon failure of the first pump. The backup selector is configured to switch to a second backup mode to supply the second sup-system from the first pump upon failure of the second pump.