外文翻譯降低汽車噪聲的方法

1、ways to reduce vehicle noisewith the rapid development of automobile industry, there is comfort and vehicle vibration and noise control of more and more stringent requirements. according to relevant data shows that 70 percent of the city noise from the traffic noise, and traffic noise is mainly car

2、noise. it is seriously polluting the urban environment, affecting peoples life, work and health. so noise control is not only related to comfort, but also related to environmental protection. however, all also from the vibration noise, vibration can cause certain parts of the early fatigue damage, t

3、hereby reducing the service life of motor vehicles; excessive noise can damage hearing the driver will enable the rapid driver fatigue, thus driving security constitutes a grave threat. so noise control, is also related to motor vehicle durability and safety. thus vibration, noise and comfort are th

4、e three closely related, it is necessary to reduce vibration, reduce noise, but also improve ride comfort, and ensure the product economy, vehicle noise control in the standard range. one type of noise arising from car noise are the main factors of air power, mechanical drive, the electromagnetic th

5、ree parts. from the structure can be divided into the engine (ie, combustion noise), the chassis noise (ie, power train noise, all components connected with the noise), electrical equipment, noise (cooling fan noise, car noise generator), body noise (such as body structure, shape and attachment inst

6、allation unreasonable noise). one of the engine noise accounted for more than half of motor vehicle noise, including noise and body intake noise (such as engine vibration, the rotational axis valve, jin, door switches, such as exhaust noise). therefore the engine vibration, noise reduction has becom

7、e a key automotive noise control. noise requirements of regulations in europe, from october 1996 onwards, the external bus 77dba noise must be reduced to 74dba, noise was reduced by half energy, the end of the century further reduced to 71dba. japans laws and regulations, small car in the next decad

8、e to control noise standards at the following 76dba. a number of domestic cities are also planning to traffic trunk lines in 2010 to control noise at the average of less than 70dba. according to the domestic current data indicate that the domestic value of bus noise permit shall not exceed 82dba, li

9、ght trucks for 83.5dba. this shows that our country in the vehicle noise control will have to make do. noise assessment noise evaluation mainly refers to the car, outside noise and vibration adaptive value. evaluation methods can be divided into subjective evaluation and objective evaluation. subjec

10、tive assessment of the impact of vehicle noise is a major factor in comfort, loudness and uncertainties, such as semantic differential method can be used for subjective evaluation. at an objective evaluation, can be used pcnm noise measuring device for measuring test analysis; addition simulation te

11、chnology in the finite element method (fem) and boundary element method (bem) has been widely applied. noise control noise generation and dissemination in accordance with the mechanism of noise control technology can be put into the following three categories: first, the control of noise sources, ar

12、e two routes of transmission of noise control, noise three recipients are protected. one of the control of noise sources are the most fundamental, the most direct measures, including noise reduction to reduce the exciting force and the engine parts of the exciting force response, which means transfo

13、rmation of acoustic source local oscillator. however, it is difficult to control noise sources when necessary in the route of transmission of noise to take measures, such as sound absorption, sound insulation, noise reduction, vibration and vibration isolation measures. motor vehicles and vehicle vi

14、bration and noise reduction level of power, economy, reliability and strength, stiffness, quality, manufacturing costs and use are closely related. engine to reduce vibration and noise of the engine noise is the focus of automotive noise control. engine vibration and noise are generated at source. e

15、ngine noise is from fuel combustion, valve bodies, gears and piston timing noise percussion synthesis. (1) ontology engine noise lower engine noise will be ontological transformation of local oscillator sound sources, including methods such as finite element method analysis and design engines, selec

16、tion of soft combustion process, improve the structure of the body stiffness, with the use of tight space, reduce noise cylinder cover. in addition, give the engine tu damping material is an effective approach. damping materials can kinetic energy into thermal energy. to deal with the principle of d

17、amping is a damping materials and components into its vibrational energy to consume. it has the following structure: freedom damping layer structure, and spacing of freely damping layer structure, and constrained damping layer structure and spacing of constrained damping layer. it is clear that the

18、adoption of a decrease of resonance amplitude and accelerated the decay of free vibration, reducing the various parts of the chuan-zhen capacity, an increase of parts at or above the critical frequency of vibration isolation capacity. at present, some countries have designed an engine experts active

19、 vibration isolation system to reduce engine vibration, in order to achieve the purpose of noise reduction. (2) intake noise engine intake noise is one of the main noise source, the department of the engine noise of air power, with the engine speed increases to strengthen. non-supercharged engine in

20、take noise major components, including the cyclical pressure fluctuation noise, vortex noise, the cylinder of the helmholtz resonance noise. diesel engine supercharger intake noise mainly from the turbocharger compressor. two stroke engine noise from the roots pump. in this regard, the most effectiv

21、e method is the use of intake muffler. there is a resistive type muffler (absorption type), resistant muffler (expansion type, resonance type, interference-type and porous decentralized) and the composite muffler. to combine with the air filter (that is in the air filter on an additional resonance c

22、hamber and sound-absorbing material, for example, type r3238) has become the most effective intake muffler, muffler volume of more than 20dba. chassis noise (1) department of exhaust noise department of the chassis exhaust noise is the main noise sources, mainly from the exhaust pressure pulsation n

23、oise, air flow through the valve seat when issued by eddy current noise, because of boundary layer airflow disturbance caused by noise and exhaust office jet noise composition. (2) power train noise powertrain noise from the vibration caused by change gear meshing and rotating shaft vibration. gener

24、al measures taken are: first, choose low-noise transmission, engine and gearbox are two and the main reducer, such as rear axle and chassis components for flexible rubber pad connections, so as to achieve the purpose of isolation; are three-axis rotational control balance degrees, to reduce torsiona

25、l vibration. electric equipment noise (1) cooling fan noise cooling fan noise happened devices are subject to wind retaining ring, water pump, radiator and transmission, but the noise generated depends primarily on the chassis. (2) automobile generator noise automotive generator noise depends on the

26、 effects of a variety of sources, these sources have magnet source, mechanical and air power source. noise level depends on the generator magnetic structure and ventilation systems, as well as generators precision manufacturing and assembly. body noise as the speed increased, the body will be more a

27、nd more noise, and air power are the main causes of noise. therefore, the following programs to improve the body noise: first, to streamline the design of the body, achieve a smooth transition;second are in between the body and frame components to adopt a flexible connection; third， interior is soft

28、ened, such as inner mongolia at the roof and body skin the use of sound-absorbing material. in addition, the car at high speed when the tire is also a source of noise. tire tread greater, then the greater the noise. in addition, the tire tread with the noise generated also have a great relationship,

29、 there is a reasonable choice of the pattern of steel cord for radial tires to reduce tire noise are an effective way. materials for the tire, the use of more flexible and soft rubber with high, you can create a low-noise tires. other measures automobile noise control, except in the design on the us

30、e of optimization methods and optimization of selected components, it can also carry out active control of noise. this is based on sound muffler technology, the principle is: the use of electronic muffler system with the opposite phase of the acoustic noise, vibration so that the two cancel each oth

31、er out in order to reduce the noise. this muffler device used extremely advanced electronic components, has excellent noise reduction effect can be used to reduce vehicle noise, engine noise, the engine could also be used to proactively support systems, to offset the engine vibration and noise.降低汽車噪

32、聲的方法隨著汽車工業(yè)的迅猛發(fā)展，對(duì)車輛的舒適性,緩震性和噪聲有了越來(lái)越嚴(yán)格的要求。據(jù)有關(guān)資料顯示，城市噪聲的百分之七十交通噪聲，交通噪聲主要是汽車的噪音。這嚴(yán)重污染了城市的環(huán)境，影響人們的生活，工作和健康。因此，對(duì)噪聲的控制，不僅關(guān)系到人類生活的舒適性，而且與環(huán)保有關(guān)。而且，所有的這些來(lái)自震動(dòng)的噪聲，無(wú)疑的還能夠?qū)е履承┝慵脑缙谄趽p傷，從而減少了汽車的使用壽命；高分貝的噪聲還會(huì)損害駕駛員的聽(tīng)覺(jué)使駕駛員在短時(shí)間內(nèi)感到駕駛疲勞，這樣就對(duì)安全駕駛就構(gòu)成了嚴(yán)重的威脅。因此對(duì)噪聲的控制，也與汽車的耐用性和安全性有關(guān)。因此振動(dòng)，噪聲和舒適性三方面是密切相關(guān)的，既要減少振動(dòng)，降低噪音，而且還要提高乘坐舒

33、適性，保證產(chǎn)品經(jīng)濟(jì)性，使車輛的噪音控制在標(biāo)準(zhǔn)范圍內(nèi)。從汽車噪音產(chǎn)生的因素分產(chǎn)生噪聲的原因主要空氣阻力，機(jī)械傳動(dòng)和電磁三部分。從結(jié)構(gòu)上可分為發(fā)動(dòng)機(jī)（即燃燒噪聲），底盤(pán)噪聲（即動(dòng)力傳動(dòng)噪音，與噪聲有關(guān)的所有組件），電氣設(shè)備，噪聲（冷卻風(fēng)扇的噪音，汽車噪音發(fā)生器），車身噪音（如車身結(jié)構(gòu)，形狀和附件安裝不合理的噪音）。發(fā)動(dòng)機(jī)的噪音占汽車噪音的一半以上，包括發(fā)動(dòng)機(jī)運(yùn)行噪聲和車身風(fēng)口噪聲（如發(fā)動(dòng)機(jī)振動(dòng)，曲軸轉(zhuǎn)動(dòng)，進(jìn)，排氣門(mén)，排氣噪聲）。因此發(fā)動(dòng)機(jī)的振動(dòng)，已成為汽車噪聲控制降低噪音的一個(gè)關(guān)鍵因素。歐洲噪聲法規(guī)要求從1996年10月起，巴士噪音必須由77dba減少到74dba，噪音制造能力減少一半，在本世紀(jì)末

34、進(jìn)一步降低至71dba。日本的法律和法規(guī)規(guī)定，在未來(lái)的10年小型車的噪音標(biāo)準(zhǔn)控制在76dba以下。國(guó)內(nèi)一些城市也計(jì)劃在2010年交通干線的平均噪聲控制在低于70dba。國(guó)內(nèi)目前的數(shù)據(jù)規(guī)定，巴士的噪音不得高于83.5dba，輕卡的噪音不得高于82dba。這是我國(guó)在車輛噪音控制方面的準(zhǔn)則。對(duì)汽車噪音的評(píng)估與評(píng)價(jià)主要有，車外的噪音和緩振性。評(píng)價(jià)方法可分為主觀評(píng)價(jià)和客觀評(píng)價(jià)。對(duì)車輛的噪音的主觀評(píng)價(jià)有舒適性，響度以及一些不確定因素，這些因素都可用于主觀評(píng)價(jià)。在客觀評(píng)價(jià)方面，可以用pcnm噪聲測(cè)量計(jì)檢測(cè)分析設(shè)備; 除了有限元法（fem）和邊界元法（bem），仿真技術(shù)已廣泛應(yīng)用。根據(jù)噪聲的產(chǎn)生和傳播方法，可

35、以采取以下方法進(jìn)行控制：噪聲源的控制，有兩種方法控制噪音的傳播，起到保護(hù)噪音接收者的作用。對(duì)噪聲源的控制是最根本，最直接的措施，包括降低噪音，減少振動(dòng)影響力和振動(dòng)的響應(yīng)，這意味著聲源轉(zhuǎn)化為局部振蕩器。但是，當(dāng)噪聲源的噪音開(kāi)始傳播時(shí)很難對(duì)其采取有效地控制，如吸音，隔音，減少噪音，振動(dòng)和振動(dòng)隔離措施。機(jī)動(dòng)車輛和車輛的振動(dòng)和噪音的降低水平，經(jīng)濟(jì)性，可靠性及強(qiáng)度，剛度，質(zhì)量，生產(chǎn)成本和使用密切相關(guān)。汽車噪聲控制的重點(diǎn)是減少發(fā)動(dòng)機(jī)的振動(dòng)和噪音。發(fā)動(dòng)機(jī)振動(dòng)和噪聲產(chǎn)生的源頭是燃料燃燒，閥體，齒輪，活塞敲擊。（1） 發(fā)動(dòng)機(jī)自身噪音降低發(fā)動(dòng)機(jī)噪音，將發(fā)動(dòng)機(jī)機(jī)體轉(zhuǎn)變?yōu)楸镜卣袷幤鞯穆曉矗ㄖT如微分分析法和發(fā)動(dòng)機(jī)的設(shè)計(jì)，選擇輕柔燃燒，提高發(fā)動(dòng)機(jī)的剛度及改善并使用緊湊的空間結(jié)構(gòu)，降低缸蓋噪音。此外，給發(fā)動(dòng)機(jī)涂阻尼材料是一種有效的方法。阻尼材料可將熱能轉(zhuǎn)化為動(dòng)能。阻尼處理的方