Eigenanalysis of a valvetrain simplified model of a combustion engine with 3DOF

Abstract

A valvetrain is a necessary structural unit of every combustion engine with discontinued combustion process. It ensures changing cylinder filling, allow low level of exhaust emissions and an optimal combustion process. There are several types of valvetrains depending on their design solution. In principle, there are recognized older valvetrain systems marked as OHV (overhead valve engine) and OHC (overhead camshaft engine). Regardless of a type of valvetrain, they include several components, which are in mutual connection. As they are exposed to dynamic effect during operational conditions, they should have suitable dynamical properties. A valvetrain is a mechanical system. The essential dynamical properties of a mechanical system of a valvetrain of a combustion engine include eigenfrequencies and eigenmodes. The article is focused on eigen analysis of a valvetrain of a combustion engine. Equations of motion of a simplified dynamical model of a valvetrain are derived. Eigen characteristics of a chosen type of a valvetrain are calculated. Matlab software and Simpack multibody software were used for calculation of the derived equations.