Реферат: Electric Cars Essay Research Paper Electric CarsHistoryEarly
Electric Cars Essay, Research Paper
Early electric vehicles may have appeared as early as 1830. Scottish inventor Robert Davidson constructed the world’s first prototype electric vehicle in 1837, but historians generally credit J.K. Starley, an English inventor, and Fred M. Kimball of Boston with building the first practical electric cars in 1888. Later in the in the decade, William Morrison of Des Moines, Iowa, constructed his version of the electric vehicle in 1891. His vehicle required 24 storage battery cells, took 10 hours to charge, and could run for 13 hours. It could carry up to 12 people and had a 4-horsepower motor. His car could reach speeds up to 14 miles per hour. Morrison, however, never mass-produced his vehicle. The first commercially produced electric vehicle was the Electrobat. It was manufactured by Philadelphia-based Morris and Salom Company. In 1896, the Woods Motor Vehicle Company of Chicago became the first American manufacturer of electric cars.
The Electrobat was one of several electric cars, which competed in a race sponsored by Illinois publisher H.H. Kohlsaat. He had challenged inventors to come up with a car that could travel the distance from Chicago to Evanston and back (58 miles). Electric cars and gas cars competed against each other in this competition. Although none of the cars performed in an especially notable manner, the electric cars failed miserably. It seemed that the slushy country roads generated a great deal of friction, which drained the strength of the batteries quickly.
Shortly after the Kohlsaat race, Thomas Edison said he believed gasoline, not electricity, would provide the dominant power source for the automobile of the future. “As it looks at the present,” he said, “it would seem more likely that (the cars) will be run by a gasoline or naphtha motor of some kind. It is quite possible. However, that an electric storage battery will be discovered which will prove more economical, but at the present the gasoline or naphtha motor looks more promising. It is only a question of a short time carriages and trucks in every large city will be run on motors.” Thomas Edison seemed to predict the future.
Even so, in 1904 one-third of all the cars in New York City, Chicago, and Boston were electrically powered. By 1912, there were 20,000 electric cars and 10,000 electric busses and trucks were on the road in the United States. Only a handful of manufactures, notably Baker and Detroit Electric, made it into the 1930’s. Former President Woodrow Wilson owned one of the most elegant cars of the period, a 1918 Milburn Electric.
In the 1960’s and 1970’s a handful of electric car manufactures started to reappear because of the increasing concern about air pollution and a depleting supplies of petroleum. In the late 1970’s and 1980’s, manufactures started developing electric cars called hybrids. These cars have all the components of the electric cars plus an internal-combustion engine. In the late 1980’s, one of the most e technologically advanced electric cars was the Sunraycer, developed by General Motors Corporation. This experimental car used solar energy to recharge its batteries.
More recently, in 1996, General Motors Corporation announced the first modern, mass-produced car designed specifically as an electric car. Also in 1996, the Honda Motor Company introduced another electric car, the first with nickel-metal hydride batteries, for sale in the United States. Italian automaker, Fiat, announced it will begin making vehicles with a new, standard-sized battery based on a European standard in 1996.
An electric car has a battery and a controller, connected to the accelerator pedal, for directing the flow of electricity between the battery and motor. Most electric cars use lead-acid batteries, but new types of batteries, including zinc-chlorine, nickel metal hydride, and sodium-sulfur, are in the works. The motor of an electric car harnesses the battery’s electrical energy by converting it to kinetic energy. Kinetic energy is the energy that makes the car move. The driver simply switches on the power, selects “Forward” or “Reverse” with another switch, and steps on the accelerator pedal.
While the internal-combustion engine of a conventional car has many moving parts, an electric motor has only a single rotating element. Like a gasoline-powered car, an electric car has a system, called a power train, of gears, shafts, and joints that transmit motion from the motor directly to the car’s wheels. This system eliminates the need for clutches or multispeed transmissions. The driver uses an electronic controller to control the rate at which energy flows from the batteries to the motor. In order to go backward, the flow of electricity through the motor is reversed, changing the rotation of the motor and causing the power train to make the wheels go in the reverse direction.
Most electric cars have a regenerative braking system. That means the friction that builds up in the brakes charge up the battery. When drives take their feet from the accelerator, the motor acts as a generator and converts the energy caused by the movement of the vehicle back into electricity and stores it in the battery. Converting the kinetic energy into electric energy slows the car. Electric cars also have a brake pedal and a traditional braking system that slows the vehicle by stopping the wheels from turning, for quick emergency stopping.
The future for electric cars looks to be a bright one. This is because of California’s zero-emissions policy, which has been adopted by several other states. The nations electric vehicle population is due to explode by the end of the decade. According to a study by the coalition, 65,364 new electric vehicles will be available for sale in 2000 in California, Maine, Maryland, Massachusetts, New Jersey, and New York. (The latter 5 states will also have will have identical emissions policies as California.) The annual total of new electronics in those states is scheduled to rise to 175,910 in the year 2002 and to 352,320 in 2003.
Also experts are looking at alternative sources for batteries. Some experts feel hydrogen fuel cells will be the dominant motor vehicle power source. The fuels cells convert hydrogen (an element in virtually limitless supply) directly into electricity without burning it to produce heat. Vehicles that are powered by hydrogen will be 3 times as energy-efficient as compared to gasoline-burning internal combustion engines. These cars will also be “squeaky-clean” because hydrogen powered vehicles only emit water vapor as exhaust.
Another alternative source for batteries contain thin sheets of plastic called proton-exchange membranes (PEMs). These separate hydrogen ions from electrons during operation. This type of battery seems to be the best suited for motor vehicle travel. This battery could yield a fuel cell that is light, compact and inexpensive to produce on a mass basis. Sam Romano, project manager of the fuel-cell program at Georgetown says PEM technology is “perhaps 10 to 12 years away from broad commercial application.”
In all the motor vehicle market of the future is likely to feature several different fueling systems. “There’s going to be a role for all of the technologies.” Says Gloria Quinn, a spokes-woman for the Edison Electric Institute, which represents investor-owned electric power companies and electric utility holding companies. “Electric vehicles, in terms of light-duty trucks, cars and vans, make a great deal of sense. But for heavy-duty trucks, the battery technology just isn’t there at all.” Consequently, says Quinn, “Despite the environmental advantages of electric vehicles, other alternative fuel technologies will remain on the scene – and even dominate certain vehicle markets.”
There are many advantages to driving an electric car. First, they produce no exhaust pollutants, so their widespread use could reduce air pollution. Second, they use batteries so they do not consume petroleum resources. Third, electric cars are quiet. This would decrease the amount of noise pollution in congested areas. Fourth, their batteries can be recharged while the owner is home or at work. This would avoid stopping at gas stations to refuel. Finally, electric cars are more efficient than gasoline powered cars.
The chief disadvantage of electric cars is that they can travel only about 100 miles before their batteries must be recharged. Also, the batteries for an electric car are very expensive and must be replaced two or three times during the life of the vehicle. Since the batteries must fit into a small space, they can only store a limited amount of energy. Electric cars also have a below average acceleration. Most of them can only reach speeds of 62 miles per hour. They also do not have the ability to cruise or climb fast enough to compete with gasoline-powered cars and accessories, such as air condition or radios, drain the battery even more quickly. Another problem is the power required to recharge their batteries is generated at the same electric power plants that provide electricity for cities and towns.
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