Referatas
Means of transport
“Car”
2005
Walking used to be to most common way to move from one place to an other.However, postcards often also show the major means of transportations. Someof them completely disappeared little by little, like the dogs carts, someothers evolved like the bus :
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An automobile is a wheeled vehicle that carries its own motor.Different types of automobiles include cars, buses, trucks, jeeps, andvans, with cars being the most popular. The term is derived from Greek‘autos’ (self) and Latin ‘movére’ (move), referring to the fact that it‘moves by itself’. Earlier terms for automobile include ‘horselesscarriage’ and ‘motor car’. An automobile has seats for the driver and,almost without exception, one or more passengers. It is the main source oftransportation across the world.
As of 2005 there are 500 million cars worldwide (0.074 per capita), ofwhich 220 million are located in the United States (0.75 per capita).
The modern automobile
The modern automobile powered by the Otto gasoline engine was invented inGermany by Carl Benz. Even though Carl Benz is credited with the inventionof the modern automobile several other German engineers work on buildingthe first automobile at the same time. The inventors are: Carl Benz on July3, 1886 in Mannheim, Gottlieb Daimler and Wilhelm Maybach in Stuttgart(also inventors of the first motor bike) and in 1888/89 German-Austrianinventor Siegfried Marcus in Vienna.
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Nicolaus August OttoNicolaus August Otto invented the gas motor engine in 1876.
Gottlieb DaimlerIn 1885, Gottlieb Daimler invented a gas engine that allowed for arevolution in car design.
Karl Benz (Carl Benz)Karl Benz was the German mechanical engineer who designed and in 1885 builtthe world’s first practical automobile to be powered by an internal-combustion engine.
John LambertAmerica’s first gasoline-powered automobile was the 1891 Lambert carinvented by John W. Lambert.
Duryea BrothersThey founded America’s first company to manufacture and sell gasoline-powered vehicles.
Henry FordHenry Ford improved the assembly line for automobile manufacturing (Model-T), invented a transmission mechanism, and popularized the gas-poweredautomobile.
Rudolf DieselRudolf Diesel invented the diesel-fueled internal combustion engine.
Charles Franklin KetteringCharles Franklin Kettering invented the first automobile electricalignition system and the first practical engine-driven generator.
Steam powered vehicles
Steam-powered self-propelled cars were devised in the late 18th century.The first self-propelled car was built by Nicolas-Joseph Cugnot in 1769—itcould attain speeds of up to 6 km/h. In 1771 he designed another steam-driven car, which ran so fast that it rammed into a wall, producing theworld’s first car accident.
Combustion engine
In 1807 François Isaac de Rivaz designed the first internal combustionengine (sometimes abbreviated “ICE” today). He subsequently used it todevelop the world’s first vehicle to run on such an engine, one that used amixture of hydrogen and oxygen to generate energy.
This spawned the birth of a number of designs based on the internalcombustion engine in the early nineteenth century with little or no degreeof commercial success. In 1860 thereafter, Jean Joseph Etienne Lenoir builtthe first successful two-stroke gas driven engine. In 1862 he again builtan experimental vehicle driven by his gas-engine, which ran at a speed of 3km/h. These cars became popular and by 1865 could be frequently seen on theroads.
The first American automobiles with gasoline-powered internal combustionengines were completed in 1877 by George Baldwin Selden of Rochester, NewYork, who applied for a patent on the automobile in 1879. Selden receivedhis patent and later sued the Ford Motor company for infringing his patent.
Henry Ford was notoriously against the American patent system, and Selden’scase against Ford went all the way to the Supreme Court, who ruled thatFord had to pay a penalty to Selden, but could continue manufacturingautomobiles, because the technology had changed quite a bit by that time.Meanwhile, notable advances in steam power evolved in Birmingham, Englandby the Lunar Society. It was here that the term horsepower was first used.It was in Birmingham also that the first British four wheel petrol-drivenautomobiles were built in 1895 by Frederick William Lanchester who alsopatented the disc brake in the city. Electric vehicles were produced by asmall number of manufacturers.
Innovation
The first automobile patent in the United States was granted to OliverEvans in 1789; in 1804 Evans demonstrated his first successful self-propelled vehicle, which not only was the first automobile in the USA butwas also the first amphibious vehicle, as his steam-powered vehicle wasable to travel on wheels on land and via a paddle wheel in the water.
On 5 November 1895, George B. Selden was granted a United States patent fora two-stroke automobile engine (U.S. Patent 549160). This patent did moreto hinder than encourage development of autos in the USA. A majorbreakthrough came with the historic drive of Bertha Benz in 1888. Steam,electric, and gasoline powered autos competed for decades, with gasolineinternal combustion engines achieving dominance in the 1910s.
The large scale, production-line manufacturing of affordable automobileswas debuted by Oldsmobile in 1902, then greatly expanded by Henry Ford inthe 1910s. Early automobiles were often referred to as ‘horselesscarriages’, and did not stray far from the design of their predecessor.Through the period from 1900 to the mid 1920s, development of automotivetechnology was rapid, due in part to the hundreds of small manufacturers
competing to gain the world’s attention. Key developments included electricignition and the electric self-starter (both by Charles Kettering, for theCadillac Motor Company in 1910-1911), independent suspension, and four-wheel brakes.By the 1930s, most of the technology used in automobiles had been invented,although it was often re-invented again at a later date and credited tosomeone else. For example, front-wheel drive was re-introduced by AndreCitroën with the launch of the Traction Avant in 1934, though it appearedseveral years earlier in road cars made by Alvis and Cord, and in racingcars by Miller (and may have appeared as early as 1897). After 1930, thenumber of auto manufacturers declined sharply as the industry consolidatedand matured. Since 1960, the number of manufacturers has remained virtuallyconstant, and innovation slowed. For the most part, “new” automotivetechnology was a refinement on earlier work, though these refinements weresometimes so extensive as to render the original work nearlyunrecognizable. The chief exception to this was electronic enginemanagement, which entered into wide use in the 1960s, when electronic partsbecame cheap enough to be mass-produced and rugged enough to handle theharsh environment of an automobile. Developed by Bosch, these electronicsystems have enabled automobiles to drastically reduce exhaust emissionswhile increasing efficiency and power.
Model changeover and design change
Cars are not merely continually perfected mechanical contrivances; sincethe 1920s nearly all have been mass-produced to meet a market, so marketingplans and manufacture to meet them have often dominated automobile design.It was Alfred P. Sloan who established the idea of different makes of carsproduced by one firm, so that buyers could “move up” as their fortunesimproved. The makes shared parts with one another so that the largerproduction volume resulted in lower costs for each price range. For
example, in the 1950s, Chevrolet shared hood, doors, roof, and windows withPontiac; the LaSalle of the 1930s, sold by Cadillac, used the cheapermechanical parts made by the Oldsmobile division.He also conceived of the notion of the yearly model change-over, whichbecame a three-year cycle. In the second year of the cycle, the superficialappearance of the cars changed incidentally; for the third, major changestook place, e.g., the fender dies for the 1957 Chevrolet had to be modifiedto produce thin, pointed fins and squarish headlamp housings. In the nextcycle, the doors, roof, trunk, and often the suspension would have to beredesigned. Factories and the yearly work schedule had to be specialized toaccommodate these changeovers.
Such patterns became dominant for the Big Three automakers in the U.S.,though European firms neither amalgamated nor could afford the changeover.After the 1950s, when American firms tackled the technical problems of high-compression V8, automatic transmissions, and air conditioners, investmentshifted to meeting the market for non-technical matters. This wascriticized as “planned obsolescence,” although by this it was meant thatthe car would simply be made to go out of style rather than really beingtechnically surpassed. For example, only those few American cars of the1960s with front-wheel drive or a rear engine had a fully independent rearsuspension because the Hotchkiss drive was cheaper, and people were used toit. Such bad investment left American firms unprepared for the Oil Crisisof the 1970s and the rise of imported luxury cars in the 1980s.
Regulation
In almost every nation, laws have been enacted governing the operation ofmotor vehicles. Most of this legislation, including limits on allowablespeed and other rules of the road, are designed to ensure the smooth flowof traffic and simultaneously protect the safety of vehicle occupants,
cyclists, and pedestrians.In 1965, in the U.S. state of California, state legislation was introducedto regulate exhaust emissions, the first such legislation in the world.Answering this new interest in environmental and public safety issues, theDepartment of Transportation (DOT) and the Environmental Protection Agency(EPA) both introduced legislation in 1968 which substantially altered thecourse of automotive development. Since the U.S. market was the largest inthe world (and California the largest market in the U.S.), manufacturersworldwide were forced to adapt. For the first time, safety devices weremandatory, as were controls on harmful emissions. Prior to thislegislation, even seat belts were considered extra-cost options by manymanufacturers. Other countries followed by introducing their own safety andenvironmental legislation. In time, meeting regulations became the mainchallenge for the engineers designing new cars. In the decade from 1975 to1985, the world’s manufacturers struggled to meet the new regulations, someproducing substandard cars with reduced reliability as a result. However,by the end of this period, everyone had learned how to handle the newlyregulated environment. The manufacturers discovered that safety andenvironmentalism sold cars, and some began introducing environmental andsafety advances on their own initiative.
Environmental changes
The automobile is one of the most destructive modern influences on theenvironment. For a large part of its development, no consideration wasgiven to concerns such as air pollution, destruction caused by road-building, and the massively increased consumption of limited naturalresources, most notably petroleum. Some of these concerns are now startingto be addressed in some parts of the world. European Union is the leader inthat, and it has many possibilities to do so, for example because thecities in Europe are planned to pedestrians and mass transit, before theautomobile became common
The Facts about Car Exhausts
What is exhaust pollution?Your car runs by burning petrol or diesel (a complex blend of lots ofdifferent chemicals collectively called hydrocarbons) to produce harmlesscarbon dioxide and water. There are, however, some by products of thisprocess.
Some of these hydrocarbons do not get burned in your engine and passthrough the exhaust unchanged. There are two in particular, called benzeneand 1:3 butadiene that can be harmful. Not all the fuel burns upcompletely, so some carbon monoxide (CO) is also produced. These are themain pollutants produced by older, petrol driven cars, with diesels of allkinds burning their fuel much more completely, so producing negligibleamounts of them.
In the 1980s, there was a move towards “lean burn” petrol engine technology— increasing the amount of air with the fuel in the engine so that more ofthe fuel is completely burned up. This reduces the amount of the first twopollutants but tends to encourage the oxygen and nitrogen in the air tocombine to produce nitrogen oxides (NOx).
If your petrol car was registered after 1993, it will be fitted with acatalytic converter which removes 95% of these three pollutants from theexhaust as compared with a similar 1976 model.
Exhausts can also contain sulphur dioxide (SO2) from impurities in thefuel, but only 3% of the total emissions of this substance come fromtransport, the rest mainly from industry and power generation.
Recently, a health threat has been identified from particulates, or PM10s,which are microscopic soot particles produced in the combustion process.Very little particulate emission (5%) is from petrol engines, though, withmuch more (19%) coming from diesels, disproportionately from the largerdiesels in trucks and buses. The National Environmental Technology Centre(NETCEN) recently suggested that one bus can produce as many particulatesas 128 typical cars.
The final element in exhaust pollution is Ozone (O3). This is not emitted
directly but made in the air by the action of sunlight on other pollutantsto form “ground level Ozone”, which, unlike the “Ozone Layer” in the highatmosphere, is regarded as a bad thing if levels are too high. Ozone isactually broken down by Nitrogen Oxides, so one tends to be lower where theother is higher.Are these pollutants dangerous?
Most toxic substances are only dangerous when a certain level is exceeded.Your medicine cupboard is full of chemicals which are beneficial if takenas prescribed by your doctor but which will kill you if you swallow thewhole bottle. Many everyday items are poisonous if taken to excess —Vitamin A, for example, is an essential part of your diet, and lack of itis what kills hunger strikers. A Polar Bear’s liver, on the other hand,contains a lethal dose of Vitamin A!Four of the pollutants described above (Nitrogen Oxides, Carbon Monoxide,Sulphur Dioxide, and Ozone) are like this — there are accepted levels atwhich no harmful effects are observed even in sensitive population groups.For the other three (Benzene, 1:3 butadiene and particulates) there is noway of proving they are safe at any level, so the experts set standardswhere the risk to health are “exceedingly small” — in other words theycan’t actually measure it!
What are the levels of these pollutants?
The graphs shown below compare the safe levels for these pollutants withthe average across both the urban and rural measuring sites shown on Ceefaxat 7pm on Friday 27 March this year. This is likely to be a worst casescenario, being right at the end of a Friday rush hour. The worst locationis also shown. This is only one day, but if you check the figures regularlyyou will see that they are entirely typical of peak hour levels.
AIR QUALITY LEVELS AT 7pm, 27 MARCH 1998 vs SAFE LIMITS [pic]
Alternative fuels and batteries
With heavy taxes on fuel, particularly in Europe and tighteningenvironmental laws, particularly in California, and the possibility offurther restrictions on greenhouse gas emissions, work on alternative powersystems for vehicles continues.
Diesel-powered cars can run with little or no modification on 100% purebiodiesel, a fuel that can be made from vegetable oils. Many cars thatcurrently use gasoline can run on ethanol, a fuel made from plant sugars.Most cars that are designed to run on gasoline are capable of running with15% ethanol mixed in, and with a small amount of redesign, gasoline-poweredvehicles can run on ethanol concentrations as high as 85%. All petrolfuelled cars can run on LPG. There has been some concern that the ethanol-gasoline mixtures prematurely wear down seals and gaskets. Further, the useof higher levels of alcohol requires that the automobile carry/use twice asmuch. Therefore, if your vehicle is capable of 300 miles on a 15-gallontank, the efficiency is reduced to approximately 150 miles. Of course,certain measures are available to increase this efficiency, such asdifferent camshaft configurations, altering the timing/spark output of theignition, or simply, using a larger fuel tank.
In the United States, alcohol fuel was produced in corn-alcohol stillsuntil Prohibition criminalized the production of alcohol in 1919. Brazil isthe only country which produces ethanol-running cars, since the late 1970s.
Attempts at building viable battery-powered electric vehicles continuedthroughout the 1990s (notably General Motors with the EV1), but cost, speedand inadequate driving range made them uneconomical. Battery powered carshave used lead-acid batteries which are greatly damaged in their rechargecapacity if discharged beyond 75% on a regular basis and NiMH batteries.
Current research and development is centered on “hybrid” vehicles that use
both electric power and internal combustion. The first hybrid vehicleavailable for sale in the USA was the Honda Insight. As of 2005, The car isstill in production and achieves around 60 mpg.Future of the car
There will always be a strong demand for the door-to-door, on-demandservice but there are likely to be radical changes in the cars of thefuture.