2. 职称英语
  3. Electric Cars: Low-impact Vehicle After years of false s

Electric Cars: Low-impact Vehicle After years of false s

游客2023-07-29  51
问题                     Electric Cars: Low-impact Vehicle
    After years of false starts, General Motors has at last set a date for putting its first battery-powered car into production. The EV1 that will roll out of GM’s factory in Lansing, Michigan, later this year will be the first car in modern times to have been specifically designed by a big car maker to run on electricity.
    A proper marketing of electric cars?
    The timing is intriguing. GM has announced its decision just as California’s regulators are preparing to relax the strict air quality standards that were an important reason for going ahead with the project in the first place. The California Air Resources Board decided in 1990 that 2% of the vehicles sold in that state by the seven companies with the largest market share would have to be emission-free — in other words — electric-starting in 1998. By 2003, the board wanted the figure to be 10%. Now it admits that "new studies" have shown what everyone else knew all along: that its mandate (命令)would be impossible to meet using existing battery technology.
    Many challenges faced
    This is because without official bullying, people are reluctant to buy electric cars. Although the EV1 has been loaded with all sorts of baubles(花哨的小玩意儿) — dual air bags, air conditioning, power windows, even a CD stereo system — it is far from clear that these will compensate for a puny range, the basic flaw of every electrical vehicle. Publicly, GM officials claim that the car will have to be recharged every 145 km (90 miles) or so, but they concede privately that the real figure is likely to be close to 100 km. Without access to a high-speed charger, such a refill will take around 15 hours.
    Even squeezing this much range out of the EV1 has required a lot of engineering sleight (灵巧)of hand. Around 400 kg (900 lb) of lead-acid batteries are secreted about its body. To help compensate for all this weight, and to maximize the distance it can cover, the vehicle is equipped with low-rolling- resistance tyres, an aluminum chassis (底盘), a wind-cheating plastic skin and a regenerative braking system that helps to recapture energy normally lost when the brakes are applied. Even the tear-drop body shape should cut down wind resistance.
    Owners of an EV1 will have two ways of charging it. Those without access to a g20-volt power supply (most American domestic circuits are 110 volts) will have to do it the hard, 15-hour, way by plugging into a normal socket in the boot. But the preferred method is more ingenious(巧妙的): use of a paddle-like contraption (发明) that is inserted into a small slot in the car’s nose. This operates by induction(电磁感应), eliminating the risk of sparks that might ignite the hydrogen released during recharging.
    At 220 volts the paddle can give an EV1 the electrical equivalent of a full tank in three hours. Super-charged versions of the device, designed for use in service stations, shopping-malls and fast-food restaurants, can bring the batteries up to 80% strength in mere 15 minutes. The fate of the EV1 could therefore be determined by GM’s success in convincing the owners of such establishments to install these special chargers, thus creating a convenient alternative to petrol pumps for keeping a car fuelled up.
    The EV1 will be sold at a price of $ 35,000 through GM’s Saturn dealerships and, in an unusual move, under the GM brand — the first time a product has been sold using the corporation’s own name. It will initially be available only in four cities in southern California and Arizona. Environmental regulators in several other smog-bound states are also hoping to develop a market for electric vehicles, but GM’s engineers feel that the EV1’s lead-acid batteries would not function well in the sort of frigid conditions now blanketing the north-eastern states. Cold weather reduces a battery’s power and life, and increases tyre friction.
    The real purpose
    Given all this, a cynic(冷嘲热讽的人) could see the EV1 as less of a serious commercial proposition than a sacrifice. Though GM claims that trials have shown it will be popular, its real purpose may be to convince regulators that the company is genuine in its attempt to solve the emission problem. If people buy it, fine. if not, GM will be able to say that it tried but that nobody wanted the product so please do not re-impose the regulations.
    Further improvements
    Meanwhile GM’s engineers, and those of their rivals, are trying to come up with something better. Two routes are available to them. One is to abandon purity (and any hope of meeting California’s standards, should they be revived unmodified) by building cars with hybrid(混合源的)power-packs. These rely on batteries most of the time, but have internal-combustion engines as reserve. The other is to devise better batteries.
    One of GM’s rivals, Chrysler, has just unveiled a prototype that follows the hybrid route. In the Intrepid ESX, currently on display at the Detroit motor show, a set of batteries drives the vehicle’s electric motor irt urban areas. The diesel engine on board does not turn the wheels, but powers a generator that cuts in to charge up the batteries when they are low. The engine can also be turned on daring long-distance driving to supply power directly to the electric motor, and reduce the load on the batteries. Since the diesel is not actually driving the wheels it can operate at a single, optimal speed, thereby emitting only a fraction of the pollutants put out by even the cleanest of conventional cars a point that the makers hope will be taken into account in making future regulations less absolutist(绝对的).
    Hybrids would reduce the need to create a new infrastructure of electric-car recharging stations, and would offer the same range between refills (which could also be carried out rapidly) as conventional vehicles. They would have their own drawbacks in the form of added cost and complexity, but they do have the advantage of not needing a fundamental technological breakthrough.
    New battery technologies
    The search for better batteries has been going on for decades, and has still failed to come up with anything credible. Several possibilities are under study. GM seems to be betting on the nickel-metal hydride (NMH) battery, which functions much like the nickel-cadmium (镍隔), or NiCad, batteries found in many domestic appliances. Early tests suggest that fitting NMH batteries to the EV1 could boost its range to more than 250 km on a single charge.
    In addition, NMH batteries, which do not rely on sulphuric(硫的)acid as an electrolyte, should last up to ten years, whereas the EV1’s lead-acid batteries will have to be replaced every two to three years. NMH batteries would operate over a wider temperature range, too. They are, however, difficult and expensive to manufacture. Robert Stempel, once chairman of GM and now filling the same role in Energy Conversion Devices, a technology firm in Troy, Michigan, has promised commercially viable NMH batteries by the end of 1997. Maybe. [br] A hybrid power-pack is a combination of different types of batteries.
选项 A、Y
B、N
C、NG
答案 B
解析
转载请注明原文地址:https://tihaiku.com/zcyy/2879620.html
相关试题推荐
随机试题
最新回复(0)