Torsional vibrations of car crankshaft engine taking into account elements of transmission

Abstract

The article is devoted to assessing the influence of the parameters of car transmission elements on the nature of the resulting torsional vibrations of the crankshaft of its power plant. As a rule, at present, the study of torsional vibrations of the crankshafts of piston internal combustion engines is carried out separately from the conditions of their operation. Only the operating modes of the engines, the torques of individual cylinders are considered, taking into account the order of operation and the angle between the flashes. If necessary, instead of a linear equivalent torsional circuit, branched circuits are considered that take into account the influence of individual engine mechanisms. Perturbing moments in such schemes occur only on the crank of the crankshaft. Only engine operating modes are considered, which take into account the elements of the car transmission and their influence on the nature of torsional vibrations along the entire length of the driven shaft. The moments of inertia of each transmission element and the stiffness of the equivalent torsional circuit sections are determined. The oscillation equations of the equivalent design scheme are drawn up taking into account the transmission elements. The values of the natural oscillation frequencies are determined by solution of homogeneous differential equations. The influence of the external environment can be estimated by applying perturbing the moment per equivalent mass replacing elements of the undercarriage of the car. Given the large values of the moments of inertia of the elements of transmission and the frequency range of their own vibrations, it is possible to explain the displacement of the amplitude of vibrations and their nodes. The considered technique is of interest for scientific and technical workers, and designers involved in the design of transmission elements for motor vehicles.