Gas Turbine Starter Generator Dwell Speed Control
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Solution Overview
Problem
Gas turbine engine start-up systems face inefficiencies due to narrow margins for fuel introduction during acceleration, leading to unburned fuel, reduced efficiency, and increased emissions, as the engine speeds and compressor speeds vary during start-up.
Innovation Solution
An engine system incorporating a starter generator and controller that provides torque to the gas turbine engine based on a dwell speed command, optimizing fuel introduction and continuing assistance post-light-off to reduce fuel consumption and emissions, with the starter generator converting electrical power to mechanical torque and adjusting its operation based on engine speed and power source levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the engine accelerates during start-up to achieve self-sustaining operation, then the engine can become self-sustaining and not require continuous starter motor assistance, but the narrow margin for fuel introduction during acceleration leads to unburned fuel and reduced efficiency
Solution Approach 1:
The system introduces fuel prior to reaching the optimal combustion speed, and the starter motor continues to provide assistance after fuel introduction to ensure the engine reaches self-sustaining speeds. This preliminary action with extended support resolves the contradiction by ensuring fuel is present when conditions become favorable while maintaining engine speed through extended starter assistance, thereby preventing unburned fuel losses.
2Reliability
If the starter motor provides continuous assistance during start-up, then the engine can reach self-sustaining speeds more reliably, but fuel consumption increases due to less than optimal fuel management
Solution Approach 1:
The engine control system monitors engine parameters such as RPM, torque, and combustion characteristics during start-up, and dynamically adjusts fuel injection timing and quantity based on this feedback. This allows the system to maintain reliable start-up performance while optimizing fuel consumption by introducing the precise amount of fuel needed at the optimal moment, rather than using fixed or excessive fuel quantities.
3Manufacturing precision
If fuel is introduced early during acceleration, then ignition may be achieved, but the margin of error for appropriate fuel amount is small leading to unburned fuel
Solution Approach 1:
The system uses dynamic fuel injection control where the fuel injection timing, duration, and quantity are continuously adjusted based on real-time engine speed and load conditions. This dynamic adjustment allows the system to maintain the precise fuel-air ratio needed for combustion across the varying engine speeds during acceleration, preventing both unburned fuel and incomplete combustion.
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 achieves efficient engine start-up by optimizing fuel-air ratios and reducing unburned fuel through controlled torque application, enhancing fuel efficiency and minimizing emissions by ensuring optimal air-fuel mixtures and extending starter generator assistance beyond self-sustaining speeds.
Implementation Method 1
The starter generator is configured convert the electrical power from the power source to mechanical power and to provide the mechanical power as torque to the gas turbine engine
Data Source
AI summary
An engine system for starting a gas turbine engine is provided. The system includes a starter generator coupled to the gas turbine engine and configured to provide torque to the gas turbine engine and a controller coupled to the starter generator and configured to provide a command signal to the starter generator. The starter generator provides the torque to the gas turbine engine based on the command signal, and the controller is configured to command the starter generator at a dwell speed until ignition.