Vibration Isolation Analysis And Optimal Design Of Pickup Power-train Mount System

The NVH represents an overall evaluation of a vehicle's quality, Automobile power-train that contains engine, clutch and transmission is one of the most important vibration source which has great effect on comfortability. Proper design of power-train mount system can reduce the vibration of power-train and body. It does not only improve the riding comfort, but also prolong the durability of engine and other components.This paper is under the support of the"NVH diagnosis Analysis and improvement of pickup"program of one automobile Co., Ltd. First, Aiming at some problems that pickup's violent vibration and great noise etc. NVH experiment is conducted about original car and benchmark respectively. It contains Mount Vibration Isolation performance test, steering wheel and driver's Seat guide rail vibration test, Interior noise test. Thus, improvement measures about original pickup can be studied out via comparation and analysis of experiment results.Second, using FEA method to check that if the mount brackets'modal frequency and stiffness can comply with requirements. Based on power-train mount vibration theory and multi-body dynamic theory, this paper applies software ADAMS to build the rigid dynamic model of power-train mount system according to mass parameters and geometry parameters that are obtained by testing the real model. Then the model can be simulated both in time domain and in frequency domain. So mount force response, acceleration response, CM displacement, CM acceleration, system frequency, vibration type, force response magnitude characteristic curves can be got to analyze the vibration isolation performance of model.Third, according to ADAMS optimization theory, In order to obtain the best vibration isolation performance of mounting system, the stiffness of mount is chosen to be design variable, the least magnitude of mount system force response is chosen to be objective function of optimization design, besides, constraints include mount displacement, system natural frequency and system decoupling. Thus, optimal model of mount system is established for optimization simulation. The results before and after optimization indicate that vibration isolation performance of the optimized mount system is improved.Finally, according to the theoretically optimal solution, put forward improvement plan of power-train mount system. Then the prototype is produced and its NVH properties are tested. The experimental data are compared and analyzed with the data of original pickup and benchmark so as to verify improvement plan. The result demonstrates that the mount system reduces vibration transmissibility from engine to body after parameters optimization, the pickup's NVH performance is improved, and the optimization result is verified to be correct and reliable.This paper discusses the NVH properties, existed problems, direction of improvement design about a type of pickup and the same series of pickups systematically. The following improvement work proves the practicability of conclusion and offers important support for improving NVH properties of domestic pickups.