Research On Modeling And Experimental Of Fully Variable Electro-hydraulic Valve

Fully variable valve timing technology is one of the key ways to solve the problem of energy-saving and environmental protection of diesel engines.The engine fully variable valve timing technology can realize the valve opening moment,the valve closing moment and the valve lift all-variable to improve the engine power,torque and fuel efficiency.For electro-hydraulic fully variable valve timing actuator,low energy consumption and high drive efficiency have always been the focus of research and attention.Establishing an mathematical model can accurately describe the dynamic characteristics,nonlinear characteristics,and system control characteristics of the actuator.Through real-time simulation to achieve system structure and performance optimization,for the realization of diesel engine Fully variable valve timing technology to provide the basis.In this paper,an electro-hydraulic fully variable valve timing actuator is optimized and designed.The valve is fully variable while retaining the original engine valve and the valve spring.By analyzing the principle of the system and using the relationship between the physical laws and system parameters,the electro-hydraulic fully variable valve actuation system establishes a mathematical model according to the three parts of the hydraulic oil pump-relief valve subsystem,the solenoid valve subsystem and the actuator subsystem.This simulation model was set up to carry out system performance simulation experiments to achieve full variable control of the engine valve opening phase,valve closing phase,and valve lift based on Simulink.Refering to optimize the gas distribution requirements for medium and high-speed diesel engines under different rotational speed conditions,in order to improve the driving efficiency of electro-hydraulic actuators,the optimization objectives are to minimize the system flow,the low seating speed,and the simple structure.Using the modeFRONTIER software,the multi-objective optimization design of the system was developed through the NSGA-II genetic algorithm.The modeling and simulation of the control system based on the incremental PID algorithm is carried out based on the optimization design.The established system control module can realize the effective control of the valve opening phase,the closing phase,the valve lift and the seating speed.According to the target model,the drive verification test is designed and built,the verification test of high pressure input part is performed,and the accuracy of the simulation model is verified.Simulation and experimental verification resultsshow that the model can truly reflect the system dynamics characteristics.The established mathematical model and control strategy provide the technical foundation for realizing the conversion of fully variable valve timing on engines.