The influencing factors of tractor fuel consumption is very much, but card friends tend to mu bai light focused on the vehicle's three big, truck high speed, air resistance concern with fuel consumption becomes weak, the air drag in the proportion of total resistance is very large, far more than other factors caused by the resistance, thus, wind resistance influence on fuel consumption is very large when the truck operation in 50 kilometers per hour, can effectively reduce the vehicle equipped with air diversion components wind resistance coefficient, improve vehicle fuel economy, so the rational use of air diversion components to reduce the wind resistance, should cause the attention of everyone, It is of great help to reduce the fuel consumption of trucks. For a truck, it is not easy to reduce the drag coefficient of the cab because it needs to satisfy the comfort brought by the wide space of the cab and ensure the safety of the drivers and passengers in the event of a collision. After years of research and development, truck manufacturers changed the traditional square head and square brain truck design elements, began to streamline the cab design, in order to obtain a lower wind resistance coefficient. In addition, by installing a guide hood on the cab, the appearance of the cab can be smoother, so as to reduce the drag coefficient of the tractor, and the vehicle can reduce the air resistance to improve its fuel economy when driving. The main diversion parts used on trucks are: cab top diversion hood, cab side diversion hood, body side skirt plate and so on. These hood components are used together to effectively reduce the drag coefficient of the tractor and improve its fuel economy. In addition, when the truck is designed, the deflector hood can also be designed as interior space. Present heavy card is more popular familial change, entertainment is changed, so spatial respect is developing towards big direction. For example, 2019 FH series models are about to launch XXL type cab. Viewed from the outside of the cab, there is no big difference between the car on sale and the high top of the cab. Two vertical "guard bars" are added in the front position of the high top part of the cab.