Air Turbine Starter Torque Control via Dual Pressure Curves
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Solution Overview
Problem
Conventional air turbine starter systems for gas turbine engines face inefficiencies in startup due to high stall torque, leading to prolonged engine startup times, as they often exceed the design torque limits of engine components.
Innovation Solution
An enhanced engine starter system with a controller that operates an air turbine starter using two-pressure level commanded starter control valves, switching between different speed/torque curves to manage torque within design limits and reduce startup duration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional air turbine starters use fixed inlet pressure and simple open/close valves, then the control system complexity is reduced, but the startup time increases and torque control precision deteriorates
Solution Approach 1:
The patent implements dynamic control of the air turbine starter by transitioning from fixed inlet pressure to variable pressure control. The system dynamically adjusts inlet pressure based on starter speed and torque requirements, enabling optimized startup performance without excessive complexity through programmable logic that adapts control parameters in real-time
Solution Approach 2:
The invention changes the operating parameters of the air turbine starter by implementing multiple inlet pressure levels (first and second pressure levels) that are switched based on starter speed. This parameter change enables the system to provide appropriate torque at different startup stages, reducing overall startup time while maintaining manageable control complexity
2Force
If conventional air turbine starters apply high stall torque at initial startup, then the torque available to start the engine is maximized, but the design torque limits of engine components are exceeded
Solution Approach 1:
The system dynamically adjusts the torque output of the air turbine starter by varying inlet pressure based on starter speed. At low speeds, the system applies lower pressure to limit torque to design limits, while at higher speeds it increases pressure to provide maximum stall torque when needed, thus resolving the contradiction between available torque and component strength
Solution Approach 2:
The invention implements periodic switching between different pressure levels (first and second pressure levels) based on starter speed thresholds. This periodic action allows the system to cycle through different torque levels appropriate to the startup phase, ensuring torque remains within design limits during critical low-speed periods while providing sufficient torque when components can withstand higher loads
3Device complexity
If conventional air turbine starters use single pressure level control, then the control mechanism is simplified, but the ability to optimize startup efficiency across different speed ranges is reduced
Solution Approach 1:
The patent segments the startup process into different speed ranges (first speed range and second speed range) and applies different pressure levels to each segment. This segmentation allows optimized control for each phase of startup, improving overall efficiency while keeping the control mechanism relatively simple through clear threshold-based switching between pressure levels
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 reduces engine startup time by maintaining torque below design limits while providing higher torque at transition speeds, optimizing the startup procedure without exceeding component design limits.
Implementation Method 1
Air turbine starters typically include a turbine that is spun to impart initial rotation to start the turbine engine
Implementation Method 2
a starter control valve configured to regulate the input pressure from the external pressure source to provide controlled pressurized air to the air turbine starter
Data Source
AI summary
An enhanced engine starter system controls an air turbine starter at the startup of operation of a turbine engine. The engine starter system includes an air turbine starter (ATS) that operates in accordance with more than one speed/torque curve during the startup procedure. A controller commands the starter control valve to provide a regulated pressure to the ATS in accordance with a first speed/torque curve to initiate the gas turbine engine startup without exceeding a maximum or design limiting torque. Overall duration of the startup procedure is reduced by the controller subsequently operating the ATS in accordance with a second speed/torque curve having a higher operational pressure once the ATS reaches a predetermined transition speed. The torque at the predetermined transition speed on the higher pressure second curve remains less than the design limiting torque, but provides a higher torque as compared to the first speed/torque curve to reduce the duration of the startup procedure.