Fuel Injector Active Flow Control via Electrically-Actuated Valve
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Solution Overview
Problem
Existing fuel control systems in turbine engines, particularly in commercial aircraft, lack active control over fuel injectors, leading to suboptimal performance and undesirable operational characteristics under varying conditions, and often require additional hardware to mitigate noise and structural issues, increasing cost, weight, and power requirements.
Innovation Solution
A fuel injector system with a housing, scheduling valve, primary and secondary fuel circuits, and an electrically-controlled valve that actively controls fuel flow in response to pressure, allowing for active adjustment of fuel flow rates above a predetermined level, using a movable spool and leak path to ensure fail-safe operation and minimize additional weight and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a mechanical fuel metering valve is used to regulate fuel flow under different load conditions, then fuel flow regulation is achieved, but the system lacks active control capability and requires additional hardware to mitigate noise
Solution Approach 1:
The patent combines a mechanical scheduling valve with an electrically-controlled valve into a single integrated fuel injector assembly. The electrically-controlled valve is positioned within the fuel circuit of the mechanical valve, allowing both mechanical passivity and electrical active control to coexist in one compact unit, eliminating the need for separate noise mitigation hardware
Solution Approach 2:
The fuel injector assembly serves multiple functions: it provides passive fuel metering through the mechanical scheduling valve, active fuel flow control through the electrically-controlled valve, and noise mitigation through the integrated design. This multi-functional approach eliminates the need for separate dedicated components for each function
2Object-affected harmful factors
If additional flow dividing hardware and fuel manifolds are added to decouple heat release and noise, then noise is mitigated, but cost, weight, and power requirements increase significantly
Solution Approach 1:
The patent extracts the active control function from separate flow dividing hardware and manifests it within the fuel injector itself through the electrically-controlled valve. This eliminates the need for additional external manifolds and flow dividing components, significantly reducing system weight while maintaining noise mitigation capability
Solution Approach 2:
The patent adds the dimension of electrical control to the traditionally mechanical fuel injector. By incorporating an electrically-controlled valve that can be independently actuated, the system gains active control capability without requiring additional mechanical flow dividing hardware, thereby reducing weight
3Extent of automation
If an electrically-controlled valve is added to provide active control of fuel flow, then active control capability is achieved, but device complexity and power requirements increase
Solution Approach 1:
The electrically-controlled valve is nested within the fuel circuit of the mechanical scheduling valve. The electrically-controlled valve's port is positioned to communicate with the fuel circuit, allowing it to modulate fuel flow to the primary outlet independently while the mechanical valve handles overall fuel metering. This nested arrangement minimizes additional complexity by integrating control functions within existing structural boundaries
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 provides active control of fuel flow, reducing noise and structural stress, minimizing weight and power requirements, and enabling finely tuned flame control in the combustor, while maintaining a fail-safe configuration and reducing the need for additional hardware.
Implementation Method 1
the valve spool is resiliently urged into a fail-safe default closed position by the biasing members
Implementation Method 2
the valve spool includes a scheduling surface configured to vary flow area through the secondary fuel circuit based on position of the valve spool within the scheduling valve
Data Source
AI summary
A fuel injector for a turbine engine includes a fuel scheduling valve configured for regulation of fuel flow from a fuel inlet in response to fuel pressure received at the fuel inlet. Primary and secondary fuel circuits receive fuel from the scheduling valve, and an electrically-controlled valve is provided in fluid communication with the primary circuit, adapted and configured to actively control fuel through the primary circuit in response to a control signal.