Modelling the Valvetrain of the Car Engine to Study the Effects of Valve Rotation

Abstract

The valve performs an alternating translational motion along its axis of symmetry, which is accompanied by a rotation about its own axis, possibly due the valve body’s cylindrical geometry and due to the conjugate element, the guide, which is also a cylindrically shape body. By ensuring this rotational motion of the valve, a number of advantages are obtained, mainly related to the increase of the operating period of the valve and implicitly of the engine. Following the critical analysis of the current state of research on the valvetrain systems and the rotational motion of the valves, the advantages and the disadvantages of valve rotation during engine operation were established. To this end, it has been established that, in addition to the theoretical approach to the problem, it is necessary to create a virtual model of the valvetrain mechanism to do a thorough analysis of the problem. Based on the model, the influence of the camshaft speed, temperature and lubricating oil pressure were monitored by changing the coefficient of friction, the influence of the cam position relative to the tappet and the influence of the valve spring. In this paper, the authors want to determine the rotational motion characteristics of internal combustion engine valves and to suggest measures that can be taken to ensure valve rotation at all operating modes without the use of auxiliary devices for generating rotational motion.