Dynamic and exciting analysis with modal characteristics for valve train using a flexible model

Abstract The dynamic and exciting characteristics of a valve train system are predicted and investigated using a flexible dynamic model. In this model the elastic vibration mechanism of each flexible component is described in a floating reference frame. The mechanical impacts at the valve unseating and seating events are affected by the contact stiffness and damping of contact components. The contact force model for the cam–tappet interface was developed based on the elasto-hydrodynamic lubrication theory of finite line conjunction. The dynamic and exciting characteristics of the valve train system are influenced by its drive, natural properties and working conditions, so these factors are investigated in details. It is concluded that the dynamic responses at the low frequency range are mainly related to the cam function, namely the sectional characteristics of the cam profile; the valve train system can be easily induced to resonance between the second mode of transmission chain and the corresponding harmonic; as the rotating speed is increased, the variation of contact force can be described as: the peak values at the positive cam pseudo acceleration phase become bigger and the valley values at negative cam pseudo acceleration phase become smaller.

[1]  Zoran Bonić,et al.  Finite difference method application in design of foundation girder of variable cross-section loaded on ends , 2008 .

[2]  J. Greenwood,et al.  The Contact of Two Nominally Flat Rough Surfaces , 1970 .

[3]  In-Soo Suh,et al.  An Investigation of Valve Train Noise for the Sound Quality of I. C. Engines , 1999 .

[4]  Homer Rahnejat,et al.  Elastodynamic transient analysis of a four-cylinder valvetrain system with camshaft flexibility , 2005 .

[5]  Walter Bryzik,et al.  Simplified Elasto-Hydrodynamic Friction Model of the Cam-Tappet Contact , 2003 .

[6]  Giorgio Dalpiaz,et al.  A non-linear elastodynamic model of a desmodromic valve train , 2000 .

[7]  Jie Guo,et al.  Investigation of dynamic characteristics of a valve train system , 2011 .

[8]  Forrest W. Flocker.  Addressing Cam Wear and Follower Jump in Single-Dwell Cam-Follower Systems With an Adjustable Modified Trapezoidal Acceleration Cam Profile , 2009 .

[9]  Giorgio Dalpiaz,et al.  Elastodynamic analysis of the desmodromic valve train of a racing motorbike engine by means of a combined lumped/finite element model , 2007 .

[10]  Jongmin Lee.  Dynamic modeling and experimental verification of a valve train including lubrication and friction. , 1993 .

[11]  Homer Rahnejat,et al.  Multi-physics analysis of valve train systems: From system level to microscale interactions , 2007 .

[12]  S. Yurkovich,et al.  A method for solution of the Euler-Bernoulli beam equation in flexible-link robotic systems , 1989, IEEE 1989 International Conference on Systems Engineering.

[13]  Jorge Martins,et al.  Valve Motion Modelation for Use in Airflow Engine Simulation , 2001 .

[14]  Jinghua Guo,et al.  Development and validation of a rigid–flexible coupled dynamic valve-train model , 2012 .

[15]  Jaan Kiusalaas,et al.  Numerical Methods in Engineering with MATLAB®: Index , 2005 .