Single-Spool Turboshaft Engine Control Algorithm for Fuel Efficiency
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Solution Overview
Problem
Current single-spool turboprop engine control systems face challenges in preventing compressor stall or surge while minimizing fuel consumption and maintaining mechanical and thermal limits, especially during varying flight conditions and takeoff/landing operations.
Innovation Solution
The system employs a control algorithm that adjusts fuel flow and propeller blade pitch based on real-time measurements of inlet air temperature and pressure, using torque and speed control schedules to optimize engine performance, ensuring efficient operation within safe limits and minimizing thrust specific fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fuel flow is increased to maintain engine power during varying flight conditions, then engine performance is maintained, but fuel consumption increases
Solution Approach 1:
The control system dynamically adjusts fuel flow and propeller blade pitch based on real-time operating conditions (inlet air temperature, pressure, engine speed, torque) to maintain optimal performance while minimizing fuel consumption. The system transitions between different control modes (torque control, speed control, idle control) depending on flight conditions.
Solution Approach 2:
The system changes operational parameters (fuel flow rate, propeller pitch angle, engine speed) based on measured conditions such as inlet air temperature and pressure. Control schedules define optimal parameter combinations across different operating regimes to achieve fuel efficiency while maintaining performance.
2Power
If engine speed is increased to improve power output, then engine power increases, but compressor surge margin decreases
Solution Approach 1:
The control system continuously monitors engine operating parameters including compressor inlet conditions, engine speed, and torque to determine the current operating point. Based on this feedback, the system adjusts fuel flow and propeller pitch to maintain adequate compressor surge margin while maximizing power output within safe operating limits.
Solution Approach 2:
The control system proactively prevents compressor surge by maintaining operating points within safe margins before surge conditions can develop. Control schedules are designed to keep the compressor operating away from surge boundaries, preventing harmful vibrations and potential damage before they occur.
3Use of energy by moving object
If propeller blade pitch is adjusted to optimize fuel efficiency, then fuel consumption decreases, but engine torque control precision is reduced
Solution Approach 1:
The control system segments the operating range into distinct modes: torque control mode for takeoff and high-power operations, speed control mode for cruise and efficient operations, and idle control mode for low-power conditions. Each mode uses optimized control strategies appropriate to the operating regime, maintaining both fuel efficiency and control precision where needed.
Data Source
AI summary
One of a controllable load and a fuel flow to a single-spool turboshaft engine is controlled so that a rotational speed of a single-spool turboshaft engine is substantially regulated to a level corresponding to a corrected rotational speed command, and the other of the fuel flow and the controllable load is controlled so that a torque transmitted from the single-spool turboshaft engine to the controllable load is substantially regulated to a level corresponding to a corrected torque command. Under at least one operating condition, the corrected rotational speed command is determined so as to minimize or nearly minimize a measure of fuel consumption by the single-spool turboshaft engine when operated so that the torque transmitted to the controllable load corresponds to the corrected torque command.