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A (2015· 淮安市第二次调研测试)Fuel Cell Technology for Cars Fill her up with hydrogen? That’s what some California motorists may be saying soon，as car makers try to speed up production of zero emission(零排放) cars to meet state requirements in the near future.Beneath the skin of this ordinary looking Hondas FCX Concept Vehicle sits an electrochemical reactor：a handbuiltn as a fuel cell.It’s expected to be running ordinary family cars on California’s roads within three years. So what exactly is a fuel cell，anyway? Why are governments，private businesses and academic institutions cooperating to develop and produce them? A fuel cell，very simply described，is a power generator，making electricity through the combination of hydrogen and oxygen.Fuel cells generate electrical power quietly and efficiently，without pollution.Unlike power sources that use fossil fuels，the only byproducts from an operating fuel cell are heat and water.To be more technical about it，a hydrogen atom with its one electron，attempts to pass through a fuel cell membrane(膜) to unite with an oxygen atom.The membrane allows only the hydrogen proton(质子) to pass through80percent efficient.That is，it turns 80 percent of the energy content of the hydrogen into electrical energy.However，we still need to turn the electrical energy into mechanical work.This is accomplished by the electric motor.A reasonable number for the efficiency of the motor is about 80 percent.So we have 80percent efficiency in generating electricity，and 80percent efficiency turning it into mechanical power.That gives an overall efficiency of about 64 percent.Honda’s FCX concept vehicle reportedly has 60percent energy efficiency，which is twice or even three times more efficient than usual cars. | 
