我国地域辽阔，南、北方气温差别较大，特别是在冬季，东北、西北的气温最低可达零下40C左右，这给我们的工作带来很大不便。而我国的汽车、农用运输车、大中型拖拉机、工程机械等的保有量又很大，随着国家汽车产业政策的实施和轿车逐步进入家庭，私人汽车的拥有量也将大为增加 China has a vast territory with large differences in temperature between the south and the north. Especially in winter, the temperature in the northeast and northwest reaches a minimum of minus 40 ° C, which brings great inconvenience to our work. In China, the ownership of automobiles, farm vehicles, large and medium-sized tractors, construction machinery and so on is very large. With the implementation of national automobile industry policies and the gradual entry of cars into homes, the ownership of private cars will also be greatly increased