今后50年,世界人口将由60亿增加到100亿,汽车数量将由0.7亿辆增加到2.5亿辆。世界人口和汽车的增长趋势如图1所示。如果这些车辆都采用内燃机,那么所需的燃油从何而来?而其排出的废气又将如何处置?那样我们的天空将永远是灰色的而不是蓝色的。因此我们必须开发清洁、高效、智能的交通车辆,才能使21世纪的交通可持续发展。货运卡车作为汽车的重要 In the next 50 years, the world population will increase from 6 billion to 10 billion and the number of cars will increase from 70 million to 250 million. The growth of the world’s population and cars is shown in Figure 1. If these vehicles use internal combustion engines, where does the fuel needed come from and how will the exhaust gases be disposed of? That way our sky will always be gray instead of blue. Therefore, we must develop clean, efficient and intelligent transport vehicles in order to make transport sustainable in the 21st century. Freight truck is important as a car