The Matching Study Of Engine Mount Components Performance Characteristics And Vehicle Working Conditions

With the developing of automobile industry and people's requirement on the riding comfort of automobiles is increasing.Good performance of NVH is an important symbol of present-day automobiles.What is called NVH,it means Noise,Vibration,Harshness(the feeling of body for noise and vibration,or infection of body by noise and vibration).Automobile powertrian is one of most important vibration and noise source of vehicle,which affects the performance of full vehicle mostly.There are two vibration resources in automobile,one is the road surface random exciting while running;The other one is vibration of engine while working. Therefore,it's becoming a key design technology to damp and isolate vibration between powertrian and frame.In a general way,the first one has great influences on the passenger,but with the improvement of road conditions and the consummate of the mount frame system designing,the influences in this aspect are lowered to a certain degree;On the other hand,the design of modern car emphasized on loweringthe weight,adopting new-type,high-strength,light-nature materials in order to lower the mass of the whole vehicle,but it is too hard to lower the weight of engine,thus the proportion of the engine in the weight of the whole vehicle goes up.But most of the engine is four-cylinder four-stroke which are lack of balance characteristic,most of the car use integrity pattern and thin-cell-fabric body which leads to the increasing of the flexibility of the bodywork and the trend of vibration goes up,the vibration exciting of the engine on the bodywork increase comparatively.Thus the vibration exciting of the engine becomes the main vibration resourse of car.Powertrain mounting system is the most important vehicle vibration subsystem, the performance of this system decides the vibration transfer.A good powertrian mounting system can control the engine force transfer to car body preferably,not making the chassis and car body bring violent vibration and noise when working,improving the vehicle ride comfortableness and used reliability. How to design high-performance vibration isolation mounting system to effectively isolate the transmission of engine vibration to the body , automotive design is an important aspect. The main performance parameters with impacting vibration isolation of the mounting system is the mount stiffness, installation location and installation perspective.The main objective of Mounting System Design is getting a reasonable stiffness, installation location and installation perspective, then the mounting system could have excellent performance vibration isolation.In order to improve the performance of powertrian rubber mounting system,based on some parameter of a car which collocated engine powertrian mounting system made in our country,using dynamic simulation software ADAMS,building a powertrian mounting system dynamic model with 6-Degree-of-Freedom (DOF),and simulating in various designed conditions, the main job include the following:1. In recent several tens years,people do much study on powertrian mounting system.Both the design of powertrian mounting system and the exploitation of the mounting components gain a great deal of successful experiences. In this paper, based on a large number of references about the study of powertrian mounting system at home and abroad,the developing history of mounts is reviwed, including rubber mount and hydraulic mount.This dissertation summarizes some design principle and research result for the powertrian mount system.2. Expatiating the function of powertrian mounting system;Showing the familiar form of laying and supporting for powertrian mounting system.Expression of steady state stimulates and the transient stimulates are giving; Analysing the range of powertrian rigid body frequency. Use the model, the inherent characteristics of static analysis, dynamic analysis and system transfer rate calculation methods of the mounting system are gotten.3. Based on the theory of multi-body dynamics and vibration theory, through on the measured parameters, establish the powertrain mounting system ADAMS model.In the ADAMS software model of the inherent characteristics of the analysis, and then separately in the design of the five typical operating conditions, the vibration response of the model analysis, rendering the powertrain at the limits of the various conditions bitmap, in order to provide a reference layout engine inside in a number of conditions, the stiffness of the suspension components for the design of the match.4. This paper takes the energy decoupling of the powertrain mounting system as the optimizing goal and the stiffness parameters of the mount components were optimized design variables, then have been relatively satisfied with the results.