Synchronized Fuel Injection in Constant-Volume Combustion
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Solution Overview
Problem
Piloting fuel injection in constant volume combustion systems for turbomachines is complex and difficult to implement, requiring optimization of fuel injection times and synchronization with other elements to improve combustion efficiency.
Innovation Solution
A constant volume combustion system using a selective shut-off element with integrated fuel injection synchronization, where the same mechanical part controls air and fuel injection, optimizing injection times with rocker arms and injection cams, and incorporating an aerodynamic injection device for low-pressure fuel delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional fuel injection system is used in constant volume combustion, then fuel can be injected into the combustion chamber, but the injection timing and synchronization with inlet/outlet orifices is complex and difficult to implement
Solution Approach 1:
The patent merges the fuel injection control function with the existing selective shut-off element that controls inlet and outlet orifices. The shut-off element is equipped with injection cams that directly actuate the fuel injection valves, eliminating the need for separate complex timing control systems. This integration simplifies the overall system while achieving precise synchronization of fuel injection with combustion and exhaust phases.
Solution Approach 2:
The selective shut-off element serves multiple functions: it controls the inlet and outlet orifices for constant volume combustion and simultaneously controls the fuel injection timing through integrated injection cams. This multi-functional design reduces the number of separate components and simplifies the injection system architecture.
2Productivity
If high-pressure fuel injection is used to improve combustion efficiency, then fuel injection performance is enhanced, but the system complexity and implementation difficulty increase
Solution Approach 1:
The patent employs injection cams with variable profiles that dynamically control the fuel injection process. The cam profiles are designed to provide optimal injection timing, duration, and pressure for each combustion phase. This dynamic control mechanism achieves high combustion efficiency without requiring complex high-pressure injection systems, as the cam geometry itself regulates the injection parameters.
Solution Approach 2:
The injection cam profiles are designed with specific geometric parameters that change throughout the injection cycle, allowing control of injection timing, duration, and fuel flow rate. By optimizing these cam parameters, the system achieves efficient combustion while maintaining a relatively simple mechanical injection mechanism without complex high-pressure systems.
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
This solution ensures efficient synchronization of fuel injection with combustion and exhaust phases, improving overall combustion efficiency and reducing fuel consumption by eliminating the need for high-pressure fuel injection.
Implementation Method 1
Through its design, the injection cam allows both pressurizing the injected fuel and controlling the injected amount
Implementation Method 2
an aerodynamic injection device configured to supply fuel to each combustion chamber in a synchronized manner via one or several injection orifices present on the shut-off element
Implementation Method 3
each combustion chamber comprises a fuel injection device whose opening and closing are synchronized by the shut-off element
Implementation Method 4
one or several fuel injectors which are able to inject fuel into the admitted air stream in order to burn it and thus cause the emission of hot gases
Data Source
AI summary
A constant volume combustion system for a turbomachine comprises a plurality of combustion chambers distributed annularly about an axis, each combustion chamber comprising an inlet orifice and an outlet orifice, a selective shut-off element movable in rotation relative to the combustion chambers, the selective shut-off element comprising a shroud facing the inlet and outlet orifices of the combustion chambers. The shroud including on a first annular portion at least one intake aperture intended to cooperate with the inlet orifice of each combustion chamber during the rotation of the selective shut-off element and on a second annular portion at least one exhaust aperture intended to cooperate with the outlet orifice of each combustion chamber during the rotation of the selective shut-off element. Each combustion chamber comprises a fuel injection device whose opening and closing are synchronized by the shut-off element.