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More and more, the automotive vehicle consumers tend to opt for internal combustion engines which use chain in their timing system, since the chain drive system presents high durability, avoiding the usual maintenance common to the belt timing system. The necessity of developing parts which increase the fuel consumption efficiency and minimize noise and vibration leads to the study and comprehension of some physical phenomena such as “polygonal action” and the ability of predicting the fluctuation of angular velocity of the sprockets used for timing the crankshaft and camshaft. The study of mathematic models in parallel to the physical test guides the development of the present work.

One of the steps towards higher efficiency internal combustion engines (ICEs) is the application of new improved subsystems, with lower power consumption. One of such subsystems is the needle roller bearing valvetrain, where rolling bearings replace the common sliding bearings designs as camshaft supports, hence decreasing the frictional torque and increasing liquid power at the crankshaft. However, the first question to arise is the vibration characteristic of the system for the new design. In order to initiate the assessment of the vibration behavior of the camshaft, some fundamental investigations should be made, such as natural frequency identification. For that, one might benefit from virtually evaluate these characteristics via FEA / Rotordynamics algorithm, reducing the need for expensive experimental setups of the complete valvetrain. This work intends to assess the applicability of these both methods to the camshaft vibration problem.

The primary belt drive is required to synchronize the crankshaft and camshaft of internal combustion engines, keeping the belt tensioned. In order to provide optimum setting of the belt force (compensation of fluctuations in the belt force due to temperature, wear or dynamic effects) automatic belt tensioning system is used, nevertheless, the components of such systems are liable to high dynamic loading condition. Oscillatory loading and noise arise from the engine internal combustion and primary belt drive components can present failures even with conservative designs concerning to static loading. This paper intends, by means of numerical methods, such as Finite Elements Method (FEM) through the commercial software Abaqus, analyze the dynamic behavior of critical components of the primary belt drive system, in order to avoid failures due to dynamic excitation and resonance.