Vibration Analysis of a Nonlinear Drivetrain System in the Presence of Acyclism

Drivetrain vibrations are a great concern in the automotive industry, once they are related to many Noise, Vibration and Harshness (NVH) phenomena. An automobile drivetrain system generally consists of the following main components: engine, clutch, gearbox, disk brake, and transmission shafts. This paper represents a nonlinear dynamic model for each drivetrain components in the presence of the acyclism phenomena (cyclostationary regim). This model is simulated by 18 degrees of freedom. The governing nonlinear time-varying motion equation formulated is resolved by the analytic Runge–Kutta method. The dynamic responses of the clutch and the single-stage helical gear reducer are investigated in the idle engine regime. The results are presented in the time and time-frequency domain by using the Wigner-Ville distribution. The dynamic behavior study of the system, comes to confirm the significant influence of the engine excitation (torque and speed fluctuation), particularly in the case of the gasoline engine acyclism condition.