The current widespread use of the fuel engine car has a variety of ills, statistics show that accounted for more than 80% of the road conditions, a common car only use the power potential of 40%, in the urban area will fall to 25%, more serious is the emission of waste gas pollution environment. Since the 1990s, the world has become increasingly vocal in improving environmental protection, and a variety of electric vehicles stand out. Although it is widely believed that the future is the world of electric cars, the current battery technology problems hinder the application of electric vehicles. Since the battery's energy density is a hundredfold from petrol, and far from reaching the required value, experts estimate that electric cars will not be able to replace fuel-engined vehicles within 10 years (unless there is a major breakthrough in fuel-cell technology).
The reality forces engineers to come up with a way to develop a hybrid power plant (hybrid-electricvehicel, abbreviated HEV). The so-called hybrid power plant is the combination of Motor and auxiliary Force unit in a car to do the driving force, the auxiliary power unit is actually a small fuel engine or power generation unit. The image is that the traditional engine as small as possible, so that a part of the power from the battery-motor system to bear. This hybrid power plant has not only played the long time of the engine, the advantages of good dynamic, but also can play the electric motor pollution-free, low noise benefits, the two "side-fight", from each other, the car's thermal efficiency can be increased by more than 10%, exhaust emissions can be improved more than 30%