Fuel Pump Bypass Pressure Control for Aircraft Cruise Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional fuel pumps in aircraft operate inefficiently at cruise and idle conditions due to excessive power consumption and pressure requirements, as they are sized for maximum takeoff conditions, leading to unnecessary power draw and weight.
Innovation Solution
A fuel pump system with a bypass line and pressure regulating valve (PRV) maintains constant pressure by bypassing flow from the output to the input line, using a constant speed motor to optimize power usage and reduce weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the fuel pump is sized for maximum takeoff conditions, then the required pressure and flow are delivered at takeoff, but the pump draws excessive power and requires a larger motor at cruise and idle conditions
Solution Approach 1:
The system dynamically adjusts the operating conditions of the pump by introducing a bypass line with a pressure regulating valve. The valve opens or closes based on the pressure differential between the pump outlet and inlet, allowing the pump to operate at optimal points across different flight conditions (takeoff, cruise, idle) without requiring a motor sized for maximum power consumption at all times.
Solution Approach 2:
The bypass valve changes the flow parameters by redirecting fuel flow through the bypass line when the pressure differential indicates unnecessary pressure delivery. This modifies the effective flow rate and pressure at the pump outlet, allowing the pump to deliver reduced flow at cruise and idle conditions while maintaining adequate pressure through the bypass mechanism.
2Weight of moving object
If the motor is sized for maximum power output, then the pump can deliver required pressure at takeoff, but the motor and components become heavier
Solution Approach 1:
The system makes the pump operation dynamic by adding the bypass line with pressure regulating valve. This allows the pump to adjust its operating point based on actual demand, enabling the use of a smaller, lighter motor that only needs to provide maximum power when actually required (takeoff), rather than being oversized for all operating conditions.
Solution Approach 2:
The bypass line extracts excess flow from the pump outlet and redirects it back to the inlet when pressure is excessive. This extraction mechanism allows the main pump to operate at lower, more efficient speeds, reducing the motor power requirements and enabling weight reduction of the motor and associated components.
3Productivity
If the pump operates at reduced flow at cruise and idle, then fuel consumption is reduced, but the inducer pump produces excessive pressure rise and requires more power
Solution Approach 1:
The system converts the harmful effect of excessive pressure rise at low flow into a beneficial mechanism. The pressure regulating valve uses the excess pressure differential to open the bypass line, which then recycles flow back to the inlet. This transforms the waste pressure energy into a useful flow control mechanism that maintains optimal pump operating points across all flight conditions.
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 reduces power consumption and weight by maintaining optimal pressure at cruise and idle conditions, achieving efficient operation with a smaller motor and lighter components.
Implementation Method 1
The PRV is configured to open as a function of pressure differential between the output line and the input line
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A fuel pump system (100) can include a motor (101) and a pump (103) connected to the motor. The pump can be configured to receive an inlet flow from an inlet line (105), to pressurize the inlet flow, and to output a pressurized flow to an output line (109) for an engine. The system can include a bypass line (111) disposed between the outlet line and the inlet line, and a bypass valve (113) disposed on the bypass line and configured to allow pressurized flow to flow to the inlet line in an open state, and to prevent pressurized flow from flowing to the inlet line in a closed state. The bypass valve can be configured to allow pressurized flow to flow to the inlet line to circulate flow and to maintain a constant pressure on the output line.