Speed Control Based On Model For Dual-Fuel Engine

The speed control of marine dual-fuel engines has always been an urgent problem to be solved.With the development of new technologies and the increase in demand,the engine has introduced many new types of actuators and sensors,making the speed control becomes more complicated,and traditional controller design methods are no longer suitable.Aiming at this problem,this paper takes speed control as the core purpose,and conducts a series of model-based control research on 6Kdual-fuel engines.This paper uses the mean value modeling mechanism to keep non-linear factors such as volumetric efficiency,effective thermal efficiency,friction torque,and other factors that are not easily reflected in the mechanism analysis in the form of experimental MAP diagrams in the model built.A controller-oriented design modleis established and mechanism / MAP hybrid describes a dual fuel engine model.Based on the sliding-mode control theory,a closed-loop speed controller was designed.The convergence of the controller was proved theoretically,and the influence of various control parameters on the speed control performance was analyzed.The performance of the controller is verified through simulation and experiments.Compared with the traditional PID controller,the controller can effectively improve the speed regulation performance of the engine.In order to further improve performance of the engine control,this paper studies the model-based intake flow control to improve the low thermal efficiency and high THC emissions of dual fuel engines during operation.Based on the gas flow mechanism,the engine intake process is described in detail,including engine intake flow estimation,intake manifold gas dynamic model,and throttle flow model.An engine intake flow tracking controller was designed,combined with a throttle position tracker,to form a dual closed-loop gas path control system.Simulation and experiments verify that the gas path control system has good tracking performance and real-time performance.Electronic throttle,as the execution mechanism of airway control,its control effect plays a vital role in air-path control.Therefore,this paper establishes a controller-oriented nonlinear throttle model,and analyzes various non-linear factors such as friction,return spring force,and parameter uncertainty.Aiming at solving these non-linear factors,based on high-order sliding mode theory,a robust throttle controller is designed,and the convergence interval of the system is solved.The influence of various control parameters on its control performance is studied,and it is found that it is difficult to balance the contradiction between chattering and system response speed in sliding mode control with fixed parameters.To solve this problem,the adaptive algorithm based on phase plane motion trajectory and the adaptive algorithm based on zero-crossing detection are designed.The convergence of the two adaptive algorithms is proved theoretically,and the control performance of the two algorithms is compared through simulation and experiments.