| The proportional pressure control valves are used in hydraulic systems as control elements and they play an important role in performance of these systems.The proportional pressure control valves maintain the pressure constant and control the clutch control system.However they present a complex characteristic resulted from the electric,magnetic,hydraulic and mechanical characteristics closely connected to each other which affect the performance of these elements.Most of their complex characteristics are caused by the nonlinearities presented in most of their constituent parts.The study of static and dynamic characteristic of these elements is one of the solutions for performance improvements into consideration when designing these elements.It has been shown that most performance characteristics of proportional pressure control valves are related to the flow rate of power source,overlap in spools,stiffness of spring,damping coefficient,volume of load and the performances of controller.The objectives of this research were to design and study the performance of the proportional pressure control valve two stage;analyze the impact of some design parameters such as spool size,cavities size and damping holes on the static and dynamic characteristics of the valve under study;and to use this valve to control clutch control system.The performance control analysis of the proportional pressure control valves is very important because it gives the clear understanding of some issues which may be present in the system controlled by these elements.The poor control of these elements can affect the system productivity in one way or another.The proportional pressure control valves are used in areas where fast and precise control is needed the reason why poor control of these elements can affect the system speed and stability which can leads to bad comfort for the users,damage of some parts of the system and some problems related to economy of the fuel consumption.In this research,the performance of the valve has been studied by analyzing the results of step responses obtained by simulating the developed model in Matlab/Simulink which has been proved to be a tool for predicting the behavior of a physical system under certain conditions.Matlab/Simulink modeling was based on the mathematical modeling of the system(proportional control pressure valve and clutch cylinder)with a comprehensive study of the orifice characteristics and flow,valve geometry and force interactions of both pilot and main stages,clutch cylinder and the electromagnetic part.The simulation results showed good performance of developed proportional pressure control valve to be used in in clutch control system.It has also shown that the design parameters considered affect the performance of the valve and the most affecting parameter found to be the spool size. |
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