Fuel Metering Valve Control Without Position Sensors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Gas turbine engines face increased weight, cost, and complexity due to the inclusion of electronic position sensors in fuel metering systems, which are necessary for closed-loop control but add unnecessary components.
Innovation Solution
A fuel metering system that operates in an open-loop configuration without an electronic position sensor, utilizing a servo valve and a pressure regulator to control the fuel metering valve, with a slot and fixed flow restriction to balance forces and modify fluid pressure, ensuring accurate fuel delivery based on current ranges supplied by the controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an electronic position sensor is included in the fuel metering system for closed-loop control, then the control precision is improved, but the weight, cost, and complexity of the system increase
Solution Approach 1:
The patent extracts and eliminates the electronic position sensor from the fuel metering system, transitioning from closed-loop control to open-loop control. This removal directly reduces system complexity, weight, and cost while maintaining sufficient fuel metering accuracy through alternative design features in the metering valve and flow control mechanism.
Solution Approach 2:
The fuel metering system is designed to operate autonomously without external position feedback. The metering valve and flow control mechanisms are engineered to inherently maintain proper fuel flow characteristics through their mechanical design, eliminating the need for electronic sensing and feedback systems.
2Measurement precision
If an electronic position sensor is included in the fuel metering system, then the control precision is improved, but the weight of the system increases
Solution Approach 1:
The electronic position sensor is removed from the system, directly reducing the weight of the fuel supply system. The patent demonstrates that sufficient control accuracy can be achieved without this heavy electronic component through mechanical design optimizations.
3Measurement precision
If an electronic position sensor is included in the fuel metering system, then the control precision is improved, but the cost of the system increases
Solution Approach 1:
The electronic position sensor is eliminated from the fuel metering system, directly reducing component costs, assembly costs, and maintenance costs. The patent shows that the mechanical design can achieve sufficient accuracy without requiring expensive electronic sensing and control electronics.
4Device complexity
If the system operates in open-loop configuration without position sensor, then the weight and complexity are reduced, but the measurement precision is worsened
Solution Approach 1:
The patent applies local quality by optimizing specific components of the metering valve and flow control mechanisms to provide inherent flow characteristics that maintain accuracy. The mechanical design of the valve geometry, flow passages, and spring characteristics are tailored to ensure precise fuel metering without electronic feedback.
Solution Approach 2:
The system transitions from electronic parameter control with feedback to mechanical parameter control through optimized valve geometry, spring rates, and flow restriction characteristics. These physical parameters are designed to inherently provide the required fuel flow accuracy across different operating 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 achieves sufficient accuracy for gas turbine engine performance without external position sensors, reducing weight and complexity while maintaining precise fuel control across varying power levels.
Implementation Method 1
The metering valve includes a biasing member that applies a force to the valve body
Implementation Method 2
a servo valve fluidly coupled to the second inlet of the metering valve and to a second source of fluid at a second pressure. The servo valve is in fluid communication with the second inlet and a body of the servo valve is movable relative to the second inlet to supply a fluid from the second source of fluid to apply a fluid pressure to move the valve body
Implementation Method 3
The slot is configured to variably restrict the flow of the fluid through the second outlet of the metering valve to modify the fluid pressure exerted on the valve body
Data Source
AI summary
A fuel metering system includes a metering valve having a first inlet fluidly coupled to a source of fluid at a first pressure, a second inlet, a first outlet and a second outlet. The metering valve includes a slot, and a valve body movable to control an amount of fluid supplied to the first and second outlet. The fuel metering system includes a servo valve fluidly coupled to the second inlet and to a second source of fluid at a second pressure. The servo valve is in fluid communication with the second inlet and a body of the servo valve is movable to supply a fluid to move the valve body. The slot is configured to variably restrict the flow of the fluid through the second outlet to balance a force applied by a biasing member. The fuel metering system includes a fixed flow restriction downstream of the second outlet.