附 录 AThe output of the engine speed is very high, the maximum power and the maximum torque in a certain speed area appears. In order to bring into full play the best performance engine, it must have a variable speed device, to coordinate the speed of the engine and the actual speed. Transmission can be in the course of driving in the car, and the engine between different ratios of produce, through the shift can make the engine to the best in the dynamic properties of state. The three main transmission function 1. On a wide range of vehicle driving speed change the size of the car and the size of the torque on the drive wheels. As the car driving conditions, car speeds of the different requirements and drive torque to a wide range of change. For example in the way to speed should be able to 100 km/h, and in the urban district, speed in 50 km/h often to the left. Empty car in a flat roads, driving resistance is very small, then, when the carrying the uphill, driving resistance and very big. And the car engine is the characteristic of speed range, and small torque range cant meet the actual need more road conditions. 2. Achieve drive backward. The car engine crankshaft are generally only to a direction, and the car sometimes need to be able to drive back, therefore, often used in the transmission of setting reverse to realize the car drive backward. 3. Achieve gap when clutch engaging, gearbox can not power output. For example can guarantee the engine when cut loose from the clutch drivers seat. Transmission speed transmission mechanism and variable speed by operation of two parts. Variable speed transmissions main function is to change the torque and speed of numerical and direction; Operations main function is to control the transmission mechanism, realize the transmission ratio of the transformation, namely transmission shift to realize speed torque. Mechanical transmission main application the gear transmission principle of slow down. Say simply, there are a number of different transmission ratio of gear, and the car down the behavior of the shift, that is through manipulation institutions make the different gear shift work. As in low speed, let the transmission ratio of big gear pair work, at high speed, let small gear transmission ratio. From now on the market have different models of transmission to see, the main configuration can be divided into: the manual transmission (MT), automatic transmission (AT), manual/automatic transmission (AMT), step-less transmission (CVT). 1. The manual transmission (MT) manual transmission contains array gear according to different driving conditions, drivers through the transmission control mechanisms to manually choose which a group of gear transmission, change the transmission ratio, to change speed and purpose. Because there is a shift change when gear synchronous problem, now a lot of gearbox are adopting synchronizer, in order to improve the smooth shift. Characteristics: the shift to direct, for drivers to provide more driving enjoyment. Is purely mechanical transmission, not there is too large a power loss, fuel economy performance is higher. Manual transmission structure simple, maintenance costs less. 2. Automatic transmission (AT) automatic transmission mechanism of planetary gear speed. It can according to the accelerator pedal degree and the speed change to automatic variable speed, and drivers but simply to control the accelerator control can reduce the speed, the difficulty of driving. Will tell commonly, car commonly used automatic transmission has the following kinds of types: hydraulic automatic transmission, hydraulic transmission automatic transmission, power transmission automatic transmission, etc. Among them, the most common is by the hydraulic torque converter and a variable transmission gear type of hydraulic automatic transmission, the transmission ratio can be in maximum and minimum values of between several continuous do within the scope of the stepless change. Because the hydraulic torque converter have power transmission loss, the relation between the transmission efficiency of automatic transmission usually only 85%. Features: power transmission shift smoothly, and natural transition. But the complex structure, maintenance cost is higher, power have certain loss, at the same time, reduce the fuel economy performance. 3. Step-less transmission (CVT) step-less transmission is composed of two groups of variable speed the plate and a belt of. Therefore, it is simple in structure than traditional automatic transmission, smaller. In addition, it is free to change gear ratios, so as to realize the full speed stepless speed change of the vehicle to make smooth, without the traditional transmission shift at the feeling. Features: the realization of uninterrupted power output, the dynamic performance and economic performance are better than traditional have high level automatic transmission. 附 录B发动机的输出转速非常