汽车专业毕业设计翻译

1、Semi nar of the Assembly of Europea n Regi ons onRen ewable and Alter native Sources of En ergy,1-2 July 2005, Porjus, Norrbotte n (S)6WORKSHOP 3: CLEAN VEHICLE AND CIT Y CENTRE TRANSPORTSOLUTIONSInterest in cleaner, less polluting vehicles and fuel has grown rapidly over recent years . This in tere

2、st has bee n spurred by three factors:* In creas ing aware ness and concern regardi ng the en vir onmen tal effects of vehicle use* The finan cial sav ings that vehicle operators can make by switchi ng to clea ner vehicles* In creas in gly stri ngent emissi ons legislati on.Biomass is the only renew

3、able source of transportation fuels. These renewable fuels, called biofuels, produce fewer emissi ons tha n petroleum fuels. The Europea n Union is promoti ng the market ing of gree ner cars via a comb in ati on of binding and non-binding measures.Clea n vehicles in clude low emissi on conven ti on

4、ally fuelled vehicles as well as those powered by alter native fuels. The product ion of such vehicles, gen erat ing less CO2 emissi ons, requires inno vati on in fuels, alter native power-train tech no logy, no ise reduct ion and new materials. Overall, the Europea n Union aim is to reach - by 2010

5、 at the latest - an average CO2 emission figure of 120 g/km for all new passenger cars marketed in the Union.Presentation of the most important tech nologies and fuels is given below.Source: European car industry and futureQ0坐Time/et un d 閏 ompresseur GIF sont requis pour visuahs

6、ercette image.With 42% of global product ion coming fromthe EU in 2002 , the region has the largest single market for passe nger cars in the world and is well positioned to leverage economies of scale and scope. But one major challenge lies in the adva ntage Japa nese car makers have gained in devel

7、op ing en vir onmen tally frie ndly tech no logies,“ most prominen tly the developme nt of newtech nologies/fuel comb in ati ons, in cludi ng fuel cells . As a con sequence, the report no tes,“ R&D objectivesin the automative industry should be directed towards developing environmentally friendly ve

8、hicles c , particular finding the“ adequate tech nology/fuel soluti ons-term sCcudtensuBupplygBiofuels (I): market share and making process-Biofuels curre ntly represe nt around 0.3 perce nt only of diesel and gasoli ne con sumpti on in the EU . In May 2003, the Commissi on adopted a draft directive

9、 which requires Member States to take the n ecessary measures to in crease the market share of biofuels. The Member States must en sure that the mi nimum share of biofuels sold on their markets is 2 per cent by 31 December 2005 at the latest, and 5.75 per cent by1 ,According to the Commissions 2004

10、competitiveness report: Dutch Presidency: Results of the competitiveness CouncilCompetitiveness package and automative industry (nov 25 th, 2004)December 2010. Any Member State setting lower objectives will have to justify this on the basis of objective criteria. The Commissi on estimates that an ef

11、fective impleme ntati on of the 2003 Biofuels Directive could save 19 milli on tonnes of oil by 2010.-Technically speaking, biofuels can be prepared from plants according to three major methods based either on the use of 1) glucides or cellulose or of 2) fats or of 3) any orga nic materialIn the fir

12、st method, the starch contained in the tuber (beetroot, potato) or the seed (cereals) as well as the glucose contained in the sap (cane sugar) undergo various chemical processes - hydrolysis possibly and alcohol transformation. The main biofuels prepared using this method are ethanol and ethyl terti

13、ary butyl ether (ETBE), which both can be mixed with petrol However according to EU legislation, mixtures containing 5 - 30 % ethanol are prohibited. Higher and lower blends than this are allowed. (Directives 1998/70/EC, 2003/17/EG and 2003/30/EG ). Researchers are investigating technologies for mak

14、ing ethanol from the cellulose (fiber) comp onent in biomass, like mun icipal solid wastes and agricultural residues left in the field after harvest. A pilot plant is operating in Sweden since more than a year. Technically this is an excellent method, though still too expensive. Ethanol made from or

15、ganic feedstock is sometimes called bioetha nol to disti nguish it from etha nol made from oil. Bioetha nol reduces exhaust emissi ons from carb on mono xide and hydrocarb on s. In additi on, by displaci ng gasoli ne comp onents such as sulfur, bioetha nol helps reduce the emissions of toxic effluen

16、ts from automobiles. Most important is that bioethanol reduces emissi ons of climate gases (CO2) with 70 -95 %, depe nding on product ion methods.In the sec ond method, vegetal oils from rape oil meal, or eve n from sun flower, which are mainly triglycerides, lead, after esterification, to diesters

17、which are also used as biofuels. This is commonly known as biodiesel. Biodiesel reduces emissi ons of carb on mono xide, hydrocarb ons and climate gases, but in creases the emissions of particulates (PM 10) and nitrogene oxide NOx dramatically. Particle filters can cure the particle emissions, but t

18、here is yet no commercially available method to reduce NO x. Hence biodiesel is best used in areas not sufferi ng from other high NOx -emissi onsIn the third method, orga nic material like sewage from water treatme nt pla nts, restaura nt waste, offals from slaughteries, surplus crops etc are ferme

19、nted an aerobically to produce metha ne and carb on dioxide (CO 2). This is currently commonly practised in most European cities. After taking the CO2 away (by e.g. water scrubber), this is called Biogas and is the clea nest fuel that is commercially available. Biogas emits almost no health hazardou

20、s or climate gases at all.Biofuels (II): prese ntati on of the various fuels and tech nol ogies-Liquified Petroleum (LPG)LPG is mostly propane and is used extensively where portable gas is required. It is produced during the oil refining process. LPG is a gas at room temperature and pressure, but is

21、 stored as a liquid un der pressure both on-board vehicles and at depots. Apart form the fuel storage and delivery mechanisms, LPG engines are very similar to petrol engines, and deliver similar performance. In fact, most LPG vehicles are bi-fuel, allowing the driver to cha nge from LPG to petrol an

22、d vice versa.In motor vehicles, it addresses,to some exte nt, the problems of polluti on as an alter native, mai nly to petrol. Although it is not renewable and is still based on fossil fuels, LPG is claimed to be cleaner.Forexample, the UK gover nment is en couragi ng its use by large tax con cessi

23、 ons and subsidies for con vert ing some petrol cars.The Vauxhall Vectra DualfuelSource: www.clea - Natural gasApart from being a clean source of energy, natural gas offers the advantage of ensuring security of supply. It is approximately 92% methane, with the reminder being a mixture

24、of nitrogen, ethane, propane and other gases. Natural gas, un like LPG, does not liquefy easily, so is stored on board vehicles either in compressed or liquefied form. Hence it is an excellent engine fuel, but neither form of on-board fuel storage is as convenient as the storage of petrol or diesel.

25、 For this reason the majority of natural gas vehicles are heavy-duty trucks and buses, as larger and heavier fuel tanks pose less of a problem for these vehicles.The 2003 Report of the high level experts on Alter native Fuels for the Commissi on comes to the con clusi on that n atural gas is the on

26、ly alter native fuel with pote ntial for sig nifica nt market share well above 5% by 2020 which could pote ntially compete with conven ti onal fuels in terms of the economics of supply in a mature market seenario . (They were not totally up-dated -see under Ethanol and Biogas) Natural ” gas could ga

27、in a broader market share if supported by Ion g-term tax and excise duty adva ntages, providi ng stable con diti ons un til a broad market has developed. Mature vehicle tech no logy is available, but diversity of products and services still need to be improved, says the report. To support a broader

28、commercialisation of natural gas vehicles at European level, the report recommends that codes and standards should be harm oni sed for the use of n atural gas as a motor vehicle fuel.- BiogasMost of the characteristics for natural gas also applies for biogas. Technically biogas is the same gas as Na

29、tural gas -though ren ewable -and all vehicles that can use n atural gas, can also use biogas.Opposite to what is said above -both in Europe and globally there are much more light-duty vehicles in operation than Heavy-duty. Furthermore - all modern biogas/natural gas light-duty vehicles are dual-fue

30、ls, with one tank for gas and one for petrol, giving the possibility to drive also in areas where the fuelling infrastructure is not fully developedFurthermore -produced in reas on able scale, biogas is econo mically competitive with diesel.According to Swedish and Finnish studies biogas has the pot

31、ential to substitute about 10 % of the current en ergy used for tran sport. Biogas is curre ntly used as tran sport fuel in Swede n, Fra nee and Switzerla nd. Netherland and Polen are about to start within a few years.- Etha nolEtha nol is the most com mon vehicle biofuel in the world -more tha n 6

32、millio n cars drive on ethanol today, most of them in Brazil and in USA.As pure etha nol may give start ing problems duri ng cold con diti ons, 100 % etha nol is only used un der con trolled circumsta nces (e.g. i n bus fleets) or in hot climates. Normally etha nol is ble nded with 15 % petrol to av

33、oid this problem.All etha nol cars can also run on petrol, or any mixture of etha nol and petrol, meaning that you can choose to fill your car with petrol if there is no ethanol station at hand.According to The International Energy Agency IEA, Ethanol has the potential to substitute 10 % of the petr

34、ol and 3 % of the diesel by 2020. Whe n the cellulose-based etha nol is econo mically viable, this pote ntial in creases dramatically.-Battery electric vehiclesBattery electric vehicles produce no emissi ons themselves and are gen erally charged from the n ati onal grid via sta ndard three pin socke

35、ts.Several differe nt battery tech no logies exist in cludi ng lead-acid (now quite dated), ni ckel-cadmium, nickel-metal hydride, and lithium ion . Most electric vehicles today are Peugeots or Citroens, which use nickel-cadmium cells. With their limited ranges, battery vehicles are not appropriate

36、to replace conventional vehicles for the majority of applications, but they are appropriate for certain niche markets such as urba n delivery vehicles .The electric thi nk carSource: www.clea -HybridsThe term hybrid usually refeveltacte that has both an electric motor and an in ter nal

37、 combusti on engine (ICE) . These have traditi on ally bee n either seriehybrids which the ICE acts as a gen erator producing electric current for the motor, or parallel hybrids in which both the electric motor aican drive the wheels.Both the Toyota Prius and the Honda In sightmake use of inno vativ

38、e new hybrid tech no logy and produceimpressive fuel economy and emissi ons results.The Toyota PriusSource: www.clea -Hydroge n and Fuel cellsHydrogen is a clean and storable energy vector that can be produced from a variety of primary energy sources (in cludi ng fossil, ren ewable and

39、 nu clear). In September 2003, the Commissi on prese nted a Communi cati onpropos ing the creati on of a Europea n Hydroge n and Fuel Cells Tech no logyPartnership in order to promote hydrogen research in Europe . This is regarded as a potentially abundant alter native source of en ergy. The Commiss

40、io n laun ched the Europea n Hydroge n Platform in January 2004. Hygroge ns advocates claim that the hydroge n economy would solve en vir onmen tal problems (such as global warm ing and polluti on) and secure in depe ndence of en ergy supply.A fuel cell is a con vers ion device that comb ines hydrog

41、e n fuel and oxyge n from the air to produce electricity, heat and water. It was inven ted way back in the 19th cen tury but has not become popular in the mass market, partly because they are very expe nsive and the alter natives were more appropriate for their time. In additi on they can be large,

42、difficult to operate and the tech no logy is complex. More research and developme nt is n eeded but n evertheless they are curre ntly being used in a small way. Now that the need for clean energy, with low or zero emission, is urgently recognised it is to be expected that fuel cells will become prac

43、tical alter natives soon.Fuel Cell Bus in Germa nyQuickTi me?et un d 閏ompresseurPhoto - JP EG sont requis pour visualisercette image.Source: www.envocare.co.ukClea ner petrol and dieselEmissions from petrol and diesel engines have been significantly reduced over the last ten years, driven mainly by

44、European legislation , and will continue to be reduced in the future. Lower emissions from conven ti onal fuels are achieved by a range of tech no logies in cludi ng clea ner formulati ons of the fuels, after treatme nt tech no logies that remove polluta nts from the vehicle emissi ons, and by impro

45、veme nts to fuel delivery and combusti on processes.Sources:Dutch Presidency: Results of the competitiveness Council -Competitiveness package and automative in dustry (nov 25th, 2004)Clea n urba n tran sport -results from the research Programme -Europea n Commissi on -July 2001 www.clea n-vehicles.c

46、om FUEL CELLSWhile there are different types of fuel cells, proton exchange membrane or PEM fuel cells are now used in most prototype fuel cell vehicles. Each PEM fuel cell uses a thin catalyst-coated membrane that is enclosed between graphite or ceramic plates. One side of the membr

47、ane acts as an anode, and is exposed to hydrogen gas. The other side of the membrane serves as the cathode, and is bathed in air to provide oxygen. At the anode side, a catalytic reaction occurs, causing the hydrogen to be separated into protons and electrons. The protons diffuse through the membran

48、e and reach the cathode. The electrons, however, cannot pass through this membrane and go round the membrane to reach the cathode thus causing an electric current as they travel. Once the electrons reach the cathode, another catalytic reaction takes place as the recombined hydrogen atoms join with oxygen to produce water.Individual PEM fuel cells are assembled together to form fuel cell stacks which produce enough electricity to run a car, minivans, sport utility vehicles