Turbomachine Fuel Injection Pressurization Valve
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Solution Overview
Problem
Existing fuel injection devices for turbomachines face challenges in providing sufficient fuel pressure to command variable geometry equipment during engine restarts, especially at low rotation speeds, leading to inadequate pressurization and increased costs due to the need for modifications in the metering valve and diaphragm installations.
Innovation Solution
Incorporating a pressurization and cut-off valve with a piston that applies counter-pressure to increase fuel pressure above a second threshold, allowing for efficient command of variable geometry equipment, without modifying the metering valve, by using an orifice in the valve body that opens at idle speed to achieve a higher pressurization level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the high-pressure pump is driven at low rotation speed during engine restart, then the engine can restart in-flight, but the fuel pressure is insufficient to open the pressurization and cut-off means and command variable geometry equipment
Solution Approach 1:
The pressurization and cut-off means is designed with two distinct pressurization levels: a first level for idle engine speed and a second level for high fuel flow rate operation. This segmentation allows the system to provide adequate fuel pressure at low rotation speeds during restart while maintaining the ability to command variable geometry equipment at higher speeds.
Solution Approach 2:
The system dynamically transitions between two pressurization levels based on engine operating conditions. The pressurization and cut-off means adapts its behavior according to the rotation speed, providing the first pressurization level at idle speeds and the second pressurization level at higher speeds, thereby optimizing performance across different operating regimes.
2Stress or pressure
If two levels of pressurization are implemented with separate diaphragms, then adequate fuel pressure is achieved for commanding variable geometry equipment, but the metering valve must be modified and installation costs increase significantly
Solution Approach 1:
The pressurization and cut-off means is designed to perform multiple functions within a single component structure. It provides both the first pressurization level for idle operation and the second pressurization level for high fuel flow rate operation without requiring separate diaphragms or modifications to the metering valve. The orifice in the valve body serves as the pressurization means for both levels.
Solution Approach 2:
The invention merges the pressurization means into the existing pressurization and cut-off valve structure, eliminating the need for separate diaphragm assemblies. The orifice formed in the cylindrical body of the valve integrates the pressurization function directly into the valve mechanism, reducing component count and installation complexity.
3Ease of operation
If a low pressurization level is used, then the engine can start up on the ground, but the variable geometry equipment cannot be commanded adequately
Solution Approach 1:
The pressurization system is segmented into two distinct operational levels: a first pressurization level optimized for ground start-up operations and a second pressurization level optimized for commanding variable geometry equipment during flight operation. This segmentation allows each level to be optimized for its specific function without compromising the other.
Solution Approach 2:
The pressurization system dynamically adapts to different operating conditions, providing the first pressurization level during ground start-up and transitioning to the second pressurization level during flight operation when variable geometry equipment command is required. This dynamic behavior ensures optimal performance across different operational phases.
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 enables quick and adequate fuel pressure for commanding variable geometry equipment at idle engine speed, ensuring efficient engine restarts and reducing costs by maintaining the existing metering valve configuration.
Implementation Method 1
the pressurization and cut-off valve comprising means for applying a counter-pressure on the piston, as from the idle speed of the turbomachine, thereby aiming to increase the fuel pressure above a second predetermined pressurization threshold
Implementation Method 2
the means for applying the counter-pressure comprise an orifice formed in the cylindrical body of the valve and through which passes pressure from the pump outlet
Data Source
AI summary
A fuel-injection device in a turbomachine is disclosed. The device includes a high-pressure pump supplying a flow control valve, whose outlet is connected via a pressurization and cut-off valve to a fuel-injector feed pipe. The valve is connected to the inlet and to the outlet of the pump in order to define two fuel pressurization thresholds, one of which is used to start-up and restart the turbomachine and the other is used for operating the turbomachine from an idle speed and for commanding an equipment with variable geometry.