Aircraft Turboshaft Engine Starter Torque Control
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Solution Overview
Problem
Aircraft turboshaft engines face challenges in starting up efficiently across various altitudes and climatic conditions due to varying resistive torques, leading to premature ignition window entry and ignition failure, especially in cold weather, where high-powered starters result in uncontrollable torque and rapid shaft acceleration.
Innovation Solution
A method and system that regulate the rotational speed of the compressor shaft during the first start-up phase to maintain constant acceleration, allowing the shaft to stay within the ignition window, using speed or torque references to adapt to environmental conditions, and continuous stabilization of torque during subsequent phases to ensure stable combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-powered starters are used to overcome increased resistive torque in cold weather, then the starter can successfully start the engine in cold conditions, but the shaft accelerates too rapidly and the ignition window is entered too quickly, causing ignition failure
Solution Approach 1:
The patent applies dynamics by making the starter torque adjustable and variable during the start-up process. The control system dynamically adapts the starter torque based on detected shaft acceleration and environmental conditions, transitioning from high torque in cold weather to precisely controlled torque during ignition window entry, thereby resolving the contradiction between overcoming high resistive torque and controlling acceleration rate
Solution Approach 2:
The patent changes the parameter of starter torque from fixed to variable. By continuously adjusting the starter torque parameter based on real-time feedback from acceleration sensors and environmental sensors, the system can maintain reliable starting in cold weather while preventing excessive acceleration during critical ignition phases, thus resolving the technical contradiction
2Adaptability or versatility
If the starter provides high torque to overcome resistive forces, then the engine can start under various environmental conditions, but the rotational speed increases too rapidly allowing insufficient time for correct ignition
Solution Approach 1:
The patent implements feedback control by continuously monitoring shaft acceleration, rotational speed, and environmental conditions, then adjusting starter torque in real-time. This feedback mechanism allows the system to adapt to various environmental conditions while detecting when the ignition window is approaching and reducing torque accordingly, preventing loss of ignition time
Solution Approach 2:
The patent applies preliminary action by using environmental sensors to predict resistive torque conditions before start-up begins, pre-configuring appropriate starter torque curves. During start-up, the system continuously monitors acceleration and prepares to adjust torque in advance of reaching the ignition window, ensuring adequate time for ignition across all conditions
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
Enables successful ignition and startup of turboshaft engines under diverse conditions by maintaining consistent acceleration and torque control, allowing multiple consecutive start-ups and preventing combustion chamber extinction, thus optimizing engine operation.
Implementation Method 1
a starter (or a starter generator) connected to said shaft so as to provide it with a starting torque
Implementation Method 2
a combustion chamber, a compressor shaft on which a compressor wheel is mounted to feed compressed air to said combustion chamber
Data Source
AI summary
The invention relates to a method for starting an aircraft turboshaft engine, said turboshaft engine comprising a combustion chamber, a compressor shaft on which a compressor wheel is mounted to feed compressed air to said combustion chamber, at least one starter connected to said shaft so as to provide it with a specified starting torque for driving it in rotation. The method comprises accelerating the compressor shaft during a first start-up phase, then stabilizing the rotational speed of the compressor shaft during a second start-up phase. During acceleration of the compressor shaft, the rotational speed of the shaft is regulated such that the acceleration of the shaft remains substantially constant.