الفهرس | Only 14 pages are availabe for public view |
Abstract One of the most important sources of noise and vibrations associated with vehicles is the vibration of driveline system. Most driveline systems include; manual transmission or automatic transmission systems. In this study, the torsional vibrations of vehicle driveline of both manual and automatic transmission systems are considered. In the literature, the torsional vibration modeling of driveline with manual transmission includes all torsional vibration excitation sources without considering the effect of synchronizer torque on the system is presented. However the synchronizer torque is an essential source of torsional vibration of the driveline system. In the previous literature of automatic transmission, there is a shortage study of torsional vibrations of entire driveline system which includes the automatic transmission with the torsional vibration sources such as clutches, band brakes, and one way clutches. The main source of excitation of torsional vibration of the driveline system is the engine fluctuating torque. A computer program using MATLAB subroutines has been developed to obtain this torque fluctuation for different engine parameters for subsequent use in the modeling. A mathematical model of torsional vibration for vehicle driveline system with manual transmission, including the effect of non-linear sources in the driveline system such as non-linear spring stiffness and synchronizer torque on the system torsional vibrations have been investigated. The model showed that; the instabilities commonly referred to a shunt or shuffle (longitudinal fluctuation) could occur during clutch engagement. A mathematical model of torsional vibration for vehicle driveline system with three different types of automatic transmission has been constructed. The model includes the effect of non-linear sources in the driveline system such as the coefficient of friction in the system of clutches, brakes and one way clutches and the engagement force. The system torsional vibration has been investigated. The results showed that; instabilities commonly referred to a shunt or shuffle could occur during the friction elements engagement due to torsional vibration of the system. A computer program using MATLAB subroutines has been developed to simulate the drivelines mathematical models and generate the results considering the effect of components nonlinearities. Finally, a comparison and discussion of the results between the two techniques of drivelines; manual and automatic transmission systems, have been presented. Also, a comparison between three different techniques of automatic transmission systems has been investigated. |