Variable Geometry Transient Control Logic
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for controlling transient power response in gas turbine engines, such as active bleed valve actuation and casing treatment, either increase weight, raise gas path temperature, or decrease efficiency, necessitating an improved approach to manage rapid engine power transitions.
Innovation Solution
A method and system for controlling a gas turbine engine with a variable geometry mechanism, where the power level difference is scaled by a factor based on the maximum bias level and reference power level, with predetermined positive and negative power thresholds to determine position control signals for maintaining or adjusting the variable geometry mechanism's position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If active bleed valve actuation is used to increase inlet mass flow and reduce response time, then transient power response is improved, but engine weight increases
Solution Approach 1:
The patent replaces the mechanical active bleed valve actuation system with a control algorithm that processes power level differences and generates position control signals. This substitution eliminates the need for additional mechanical actuation components, thereby avoiding weight increase while achieving the same transient response improvement through intelligent control of existing variable geometry mechanisms.
Solution Approach 2:
The patent changes the control parameter from active valve actuation to power level difference-based position control. By monitoring and responding to power level differences, the system dynamically adjusts variable geometry mechanism positions to optimize transient response without requiring additional mechanical systems.
2Speed
If passive bleed valve actuation is used to increase inlet mass flow, then transient power response is improved, but gas path temperature increases and gas generator speed decreases
Solution Approach 1:
The patent implements a feedback control mechanism that continuously monitors power level differences and adjusts variable geometry mechanism positions accordingly. This closed-loop control ensures that adjustments are made only when and where needed, preventing unnecessary temperature increases and maintaining optimal gas generator speed while still improving transient response.
Solution Approach 2:
The patent introduces dynamic adjustment of variable geometry mechanism positions based on real-time power level differences. This dynamic control allows the system to adapt to changing operating conditions, improving transient response without the adverse thermal and speed effects associated with passive bleed valve actuation.
3Speed
If the running line is lowered to improve transient engine performance, then response time is reduced, but overall efficiency decreases and specific fuel consumption increases
Solution Approach 1:
The patent applies partial action by adjusting variable geometry mechanism positions only when power level differences exceed predetermined thresholds. This selective adjustment avoids the excessive fuel consumption associated with continuously operating at lowered running lines, while still achieving improved transient response when needed.
Solution Approach 2:
The patent dynamically adjusts the operating point based on real-time power level differences, allowing the engine to operate at optimal efficiency during steady-state conditions while achieving improved transient response when power changes are detected. This eliminates the need to permanently lower the running line.
4Speed
If casing treatment is used to improve transient engine performance, then response time is reduced, but engine efficiency is lowered
Solution Approach 1:
The patent replaces physical casing treatment modifications with a control algorithm that adjusts variable geometry mechanism positions. This substitution achieves improved transient response through intelligent control without the efficiency penalties associated with physical casing modifications.
Solution Approach 2:
The patent changes the approach from physical casing treatment to control parameter adjustment. By modifying control parameters (position control signals based on power level differences), the system achieves transient response improvement without the efficiency losses inherent in physical casing modifications.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Herein provided are methods and systems for controlling an engine (10) having a variable geometry mechanism (51, 52; 130). A power level difference between a requested engine power level and a current engine power level is determined at a computing device (410). The power level difference is compared to a predetermined power threshold at the computing device (410). When the power level difference exceeds the predetermined power threshold, a position control signal for changing a position of the variable geometry mechanism (51, 52; 130) is generated and output at the computing device (410), the position control signal generated based on a requisite bias level, the requisite bias level being based on the power level difference.