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Potential improvements in spark ignited engine performance gained through the application of ceramic valve train components were predicted using state-of-the-art valve train simulation and gas exchange computer programs. The use of ceramic valves, ceramic pushrods, and ceramic hydraulic tappet housings, in combination with modified valve spring and valve lift parameters, were analyzed for a 2.8L overhead valve V-6 engine. The results show that significant improvements in dynamic valve train behavior and engine performance are possible with the largest gains coming from the use of ceramic valves. Potential improvements in valve train dynamics include: a 20% increase in maximum engine speed; a 30% reduction in the maximum valve train forces; and a 30% reduction in valve train friction. These benefits can then be used to either improve fuel economy, high speed engine power or low speed torque by up to 5%.

To drive the camshafts in modern 4-stroke-engines, roller chains or toothed belts are normally used. These components are highly loaded during engine operation, especially due to torque fluctuations at the camshafts and torsional vibrations of the crankshaft. The stresses can be increased due to vibration excitation in the drive. The goal of this paper is to describe a simulation model for the dynamic behavior of camshaft drive systems. First, the boundary conditions in a camshaft drive of an IC-engine are analysed and evaluated. Then, possible methods of mathematical simulation are discussed. Finally, to show the accuracy of the model, some calculation results are shown in comparison to corresponding measurements.