Abstract
The paper presents the research regarding the rotational movement of the engine valve and engine tappet for a direct acting valve train. The first part of the paper describes the necessity of the rotational movement of the engine valve and tappet, its advantages as well as its disadvantages. It also shows for which engine valve this motion is more necessary: intake valve or exhaust valve. The paper’s main part presents the virtual model used in the analysis. The valve train model was created using LMS Virtual Lab. In the first stage of the CAE analysis, the bodies were considered as being rigid. Flexible bodies will be used in future stages in order to include the component deformation into the calculations. The analysis was performed considering: engine speed, eccentricity value of the cam in relative position to the tappet and the value of the friction coefficient. The simulations were done at the following engine speeds: 600RPM, 2500RPM, 3200RPM and 7200RPM (maximum engine speed). Three values for cam eccentricity were used: 1.5mm, 2mm and 3mm. The rotation direction and speed were considered as performance parameters for the analysis. The simulation results revealed that the eccentric position of the cam, the engine speed and the friction coefficient are the main factors that influence the rotational movement of valve and tappet. This study is an outcome of collaboration between the Transilvania University of Brasov, Romania and an automotive parts manufacturer. The results of the project will be used to improve the design of valve train components.
Keywords: Valve Train, Engine Valve Rotation, Tappet Rotation, Virtual Model, LMS Virtual Lab