Development Of Electronic Rotating EGR Control Valve And Research Of Its Control System

EGR (exhaust gas recirculation) system is an effective method used to reduce NOx emissions from diesel engines. As a key component of the EGR system, EGR valve has important influence on reducing NOx emissions.An electric rotation EGR valve and its electronic control system are the research objects in this paper. Using CAD design method, simulation and experiment technology, and microcomputer technology, this paper mainly studies the structure and properties, theoretical model, stable and dynamic characteristics, control strategy, electrical control system for this valve. These works solve some key technologies such as the EGR valve structure, simulation and control. Last, this paper gives the EGR valve product sample and its electronic control system.Lots of test results, such as sample flow, valve lift, electrical characteristics and bench test results, show that the EGR valve sample has excellent performance, and electrical control system operation is stable, and the control effect for NOx is obvious.The research results are helpful to develop EGR system independently and improve EGR technical level in china. The main results are as follows:1) Using CAD technology, the driving electromagnet, return spring, reversing motion institutions, valve components, valve body and overall structure are designed. With the reversing motion institutions, the rotation movement is converted to linear movement, which can prevent exhaust pollutants playing bad influence on valve plate and improve the reliability and the response speed of the valve.2) Mathematic and simulation models are established. Some torques hard to quantify are combined with opening position and angular linear functions such as the axis rotation friction resistance torque, the valve stem rising resistance torque, the horizontal axis movement resistance torque, exhaust gas resistance torque, core eddy current and hysteresis torque. This simulation gives coefficients values of the function successfully. The simulation results show that the valve has illustriously steady and dynamic characteristics. 3) This paper develops an independent control system for the EGR valve. The closed-loop control method improves the precision control for EGR rate.