Gas Turbine Fuel Thrust Control Override Valve
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Solution Overview
Problem
Current thrust control override systems for gas turbine engines are complex and costly, necessitating a simpler and more economical solution to maintain engine operation during unlikely events of metered burn flow loss.
Innovation Solution
A gas turbine engine fuel control system incorporating a fuel metering valve and a thrust control valve, which can move between positions to either allow or block fuel flow, utilizing override signals to maintain a constant fuel flow rate, thereby simplifying the system and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thrust control override system is implemented to maintain engine operation during metered burn flow loss, then engine reliability is improved, but device complexity increases
Solution Approach 1:
The patent extracts the thrust control override function from the main fuel metering valve and implements it as a separate, dedicated thrust control valve. This isolation allows the override function to operate independently when needed, maintaining engine reliability without complicating the primary fuel metering system. The thrust control valve has its own inlet from the fuel pump and can bypass the metering valve entirely.
Solution Approach 2:
The thrust control valve acts as an intermediary component between the fuel pump and the fuel metering valve. It provides an alternative fuel path that can override the metering valve's control during failure conditions. This mediator approach allows the system to maintain engine operation by introducing a backup control mechanism without fundamentally redesigning the entire fuel system.
2Reliability
If a thrust control override system is implemented to maintain engine operation during metered burn flow loss, then engine reliability is improved, but manufacturing cost increases
Solution Approach 1:
The thrust control valve is designed as a relatively simple, dedicated component with a specific single function: to override fuel metering during failure conditions. By making this safety component simple and focused, the patent reduces manufacturing costs compared to more complex integrated systems. The valve can be manufactured as a straightforward on/off control element rather than a complex multi-functional device.
3Reliability
If the thrust control valve blocks fuel flow from the metering valve outlet, then constant fuel flow rate is maintained, but fuel flow to the engine is restricted
Solution Approach 1:
The thrust control valve is positioned to intercept fuel flow before it reaches the fuel metering valve's outlet. By blocking flow at this preliminary point, the system prevents uncontrolled fuel delivery and maintains a predetermined constant flow rate. This preliminary blocking action ensures that when the override is activated, the engine receives a safe, controlled amount of fuel rather than risking excessive or uncontrolled flow.
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 overrides fuel flow to maintain a predetermined constant rate, ensuring engine operation at idle speed without shutting down, thus reducing complexity and costs while protecting against potential fuel metering valve failures.
Implementation Method 1
The thrust control valve comprises a main inlet, an override inlet, and a thrust control valve outlet. The main inlet is in fluid communication with the metering valve outlet, and the override inlet is in fluid communication with the metering valve inlet. The thrust control valve is adapted to receive thrust control valve override signals and is configured, in response thereto, to move from a first position to a second position.
Data Source
AI summary
A gas turbine engine fuel control system is provided that includes a fuel metering valve and a thrust control valve. The fuel metering valve includes a metering valve inlet and a metering valve outlet. The metering valve inlet is adapted to receive a flow of fuel, and is configured to control the flow of fuel through the metering valve outlet. The thrust control valve is adapted to receive thrust control valve override signals and is configured, in response thereto, to move from a first position, in which flow from the metering valve is not impacted, and a second position, in which flow from the metering valve is blocked while flow through a fixed-area orifice is allowed.