Dynamic simulations of the engine valvetrain and detailed studies on the operating mechanisms have long been a centre of attention. In heavy duty diesel engines, heavier valvetrain parts lead to higher inertia force. On the other hand, the opening and closing of valves is very fast and high overlap in Valves lifts and necessity for increase the exhaust and inlet valve opening time by dwelling, individuates cam design basis of these engines, which cause to increase in inertia forces. A common practice in valvetrain dynamic analysis is to use rigid multibody dynamics model. However, some assumptions are to be considered to simplify the model, especially in attachments and joints. In this paper, an under development heavy duty medium speed diesel engine valvetrain system has been studied. The valvetrain mechanism has been modeled using ADAMS commercial software. The flexible valvetrain parts have been considered by means of Component Mode Synthesis (CMS) method. Instead of using simple joint assumption of rigid multibody dynamics model, contact has been employed to study the exact interaction between each two parts. In this method the clearances in the system could easily considered. The dynamic behavior of valvetrain has been investigated and the forces for the parts have been obtained and compared with rigid multibody dynamics model.
Multibody dynamics modeling of electromagnetic direct-drive vehicle robot driver
