Engine Intake And Exhaust System Simulation Analysis And Its Influence To Vehicle Noise

The motor vehicle noise influences the people who work and live outside, and on the other hand, it also harms the health of both drivers and passengers. Thus, the foreign countries with developed automotive industry have paid enough attention to motor vehicle noise in making lots of regulations and standards to control the noise since 1950s. Since 1960s, the main countries and areas such as ECE, EEC, Japan and America have modified the related regulations and standards every three to five years to lower the limit value of each vehicle noises, improve the further research and application in vehicle noise reducing technique and measuring analysis technique, and reduce the influence and harm of vehicle noise. The vehicle noise control work began from 1979 in our country. The two national standards, GB1495‐1979 Motor Vehicle Allowed Noise and GB 1496‐1979 Measuring Methods of Motor Vehicle Noise were published at that time. In 2002, our country published GB 1495‐2002 Limit Value and Measuring Methods of External Noise during Acceleration Driving on the base of GB1495‐1979 in which reduced the limit value of external acceleration driving for M1 vehicle to 74dB(A). Meanwhile, the National Development and Reform Committee planned to publish new measuring methods and limit value of external acceleration noise, and the draft version, GB 1495‐20xx has already been published. The publication of the new standards could lower the vehicle acceleration noise level.By using the transfer matrix method and simulation software of one‐dimensional acoustic performance, GT‐POWER to do the value simulation analysis of intake and exhaust system on special new vehicle with small displacement, this topic built one‐dimensional joint model for intake system and exhaust muffler with engine, solved the problems such as the model building and related parameters setting of intake and exhaust system. Take the simulation calculation result as the base of making improving proposal for noise reduction by getting the parameters such as transfer loss and pressure loss of intake system, and muffler value, transfer loss, pressure loss and exhaust back pressure of exhaust muffler through value simulation. Because the vehicle structure had been confirmed, the larger changes could not be don, except structure optimization of intake and exhaust muffler to reduce vehicle noise. Check proposal rationality and validity through the value simulation and test verification, and optimize the noise performance of intake and exhaust system on the base of value simulation result and external acceleration noise test data. The better consistency between test result of external acceleration noise and value simulation means a positive engineering practical value for using simulation software of one‐dimensional acoustic performance, GT‐POWER to optimize vehicle exhaust system noise reduction. And it solves the problem that how to reduce noise without larger vehicle changes.Under the guide of Professor Shi Wenku, the author of this article optimized the special intake and exhaust system, reduced the noise of intake and exhaust system, and then reduced the vehicle external acceleration noise by reading lots of related documents and taking the research of optimization design for intake and exhaust system during working as the base.