The analysis of operating conditions for valves actuated by camless coupled drive

The operating conditions for the pair of inlet or exhaust valves in a single engine cylinder has been analyzed. The differences for the phase angle position of cams, due to manufacturing faults, vibration and wear, result in differences in valve lifts for such a pair. The use of a single camless drive for the pair of valves cannot eliminate such differences in the valve lifts. When individual drive for each valve is used, the differences can be greater. The aim of the analysis is to determine the needed stiffness of the element connecting the pair of valves with the drive and permissible differences for geometrical and material properties of an individual drive, allowing to obtain the differences for the valve lifts smaller than those for the camshaft case. The analysis has been made using the elaborated FEM model, for two configurations of the camless drive. The paper also presents the dynamic parameters of the valves – drive assembly, stresses in such assembly and recommendations for stiffness of the element connecting the pair of valves with the drive.