Thermal Recirculation Throttle Valve for Aircraft Fuel Systems
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Solution Overview
Problem
Aircraft fuel systems face challenges in maintaining optimum operating temperatures, requiring complex and weight-heavy control systems, and there is a need for a solution that improves flight safety by ensuring fail-safe fuel flows and reducing the number of control valves.
Innovation Solution
A thermal recirculation throttle valve is designed for aircraft fuel systems, incorporating a housing with a throttling valve chamber, a power piston, a Linear Variable Differential Transformer for position measurement, and a flow deflector to manage fuel flow and temperature, allowing controlled recirculation of hot fuel and providing fail-safe operation by reducing the number of control valves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a thermal recirculation valve is used to maintain optimum fuel system operating temperatures, then fuel temperature control is improved, but the number of control valves increases and system complexity increases
Solution Approach 1:
The patent combines the thermal recirculation function with the existing main fuel throttle valve assembly by integrating a recirculation valve body, power piston, and control mechanisms into the same housing structure. This merging approach allows the system to maintain optimum fuel temperatures while avoiding the need for separate, standalone control valves, thereby reducing overall system complexity.
Solution Approach 2:
The integrated valve assembly performs multiple functions: it controls the main fuel flow to the engine through the main throttle valve while simultaneously managing thermal recirculation flow through the recirculation valve body. The power piston and control pressure system serve dual purposes of actuating both the main throttle and recirculation functions, making the system more efficient and less complex.
2Temperature
If multiple control valves are used for thermal management, then temperature control precision is improved, but aircraft weight increases
Solution Approach 1:
By merging the thermal recirculation control functions into the existing main fuel throttle valve assembly, the patent eliminates the need for additional separate control valves that would add weight. The integrated design uses the same power piston and control pressure system to manage both main fuel flow and thermal recirculation, thereby maintaining temperature control precision without the weight penalty of multiple independent valves.
3Device complexity
If a thermal recirculation valve is integrated into the fuel system, then system complexity is reduced, but the valve must provide fail-safe flows during valve failure or commanded position
Solution Approach 1:
The patent incorporates fail-safe flow paths and positioning mechanisms that automatically activate if the valve fails or is commanded to extreme positions. The recirculation valve body and power piston arrangement include inherent fail-safe characteristics that ensure proper fuel flow control even under failure conditions, thereby maintaining reliability while keeping the integrated system simple.
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 thermal recirculation throttle valve effectively maintains optimum fuel system temperatures, reduces system complexity and weight, and ensures safe fuel flows, enhancing aircraft safety and reliability by allowing controlled recirculation of fuel and fail-safe operation.
Implementation Method 1
a Linear Variable Differential Transformer for measuring a linear position of the power piston within the housing
Implementation Method 2
a flow deflector engaged with the throttling valve for protecting the housing from flow erosion from fuel exiting an outlet flow window within the throttling valve sleeve
Data Source
AI summary
A thermal recirculation throttle valve (1) for an aircraft fuel system includes a housing (11) having a throttling valve chamber; a cover (5) operatively engaging a first side of the housing (11); a power piston (6) within a power piston sleeve (7), the power piston (6) having a first (21) and second face (22) for control pressure to act upon, the power piston (6) and power piston sleeve (7) operatively engaged with the housing (11) within the throttling valve chamber; a Linear Variable Differential Transformer (15) for measuring a linear position of the power piston (6) within the housing (11); a throttling valve (8) within a throttling valve sleeve (9), the throttling valve (8) operatively engaged with the power piston (60) to transfer the linear movement of the piston (6) between a fully extended and a fully retracted operating position; and a flow deflector (10) engaged with the throttling valve (8) for protecting the housing (11) from flow erosion from fuel exiting flow windows (37). The throttling valve (8) includes a pair of fail-safe operating positions, a fully open operating position, a low leakage shutoff operating position, and a variety of variable flow operating positions between the shutoff and fully open operating positions.