车专业英语Unit-4-Passage-A课件

1、Unit Four Drive Train Passage ATransmissionsTransmission is the most important component in the drive train Often the term “transmission” refers simply to gearbox Its jobs are to vary the gear ratio, controlling the car speed; to provide directional control, forward and reverse; and to interrupt the

2、 engine power to the transmission to make the engine idleIn accordance with the operational control mode, car transmissions can be divided into manual transmission (MT) and automatic transmission (AT). There are three main kinds of automatic transmissions, respectively is automatic transmission (AT)

3、, continuously variable transmission (CVT) and direct shift gearbox (DSG).Manual Transmission (MT)A manual transmission mainly contains some shift forks, collars, different sizes of gears along the shafts such as input and output shafts, and lay shaft as shown in Fig.4-1If you drive a car with a MT,

4、 you have to shift the gears by yourself, usually with the gearshift on the console and the clutch pedal on the floor on the left sideMT usually has five speeds The first gear is the lowest gear which is used to make your car start going The second gear is used to make your car move faster The third

5、 and fourth gears mean that both input and output shafts turn at the relatively the same rate of speed The wheels can go very fastThe fifth gear is often regarded as “overdrive” which means the output shaft can turn faster than the input shaft for good fuel economy Some cars now have as many as six

6、and seven gears Although the gear ratio may be the same as in six- or seven-speed transmission as in five-speed transmission, the more forward speeds, the smoother shifting is and more fuel-efficient the car becomesAutomatic Transmission (AT)An automatic transmission is the most complicated mechanic

7、al component in todays carIt consists of mechanical system, hydraulic system, electrical system and electronic control system, all working together in perfect harmonyIf you have a car with an AT, the gears are changed automatically without any help from you This is accomplished through the torque co

8、nverter, a planetary gear set including a sun gear, planet gears and a carrier, and other shift operating devices (see Fig.4-2).All automatic transmissions have a gearshift that has at least 4 positions: park (P), reverse (R), neutral (N) and drive (D) as shown in Fig.4-3 Continuously Variable Trans

9、mission (CVT)A continuously variable transmission is not a complicated system CVT moves seamlessly from one gear ratio to the next through a pulley system which not only offers smoother shifting but also improves better fuel economy (see Fig.4-4).The major components of a CVT include an input drive

10、pulley, an output driven pulley and a metal belt as shown in Fig.4-5 Each pulley has two cones, forming a groove, and the belt rides in the two grooves As the distance between the cones changes, the belt rides higher or lower in the grooves, which determines the gear the car is inDirect Shift Gearbo

11、x (DSG)If you drive a car with DSG, the gears shift automatically, or you can manually select them by yourself without operating a clutch pedal It is known as direct shift gearbox (DSG) (see Fig.4-6a) The greatest structural difference is that a DSG has two clutches One clutch operates the odd-numbe

12、red gears, and the other clutch controls the even-numbered gearsThe result is that the flow of power to the transmission from the engine isnt interrupted as the transmission shifts from one gear to another The DSG also has two transmission input shafts, one inside the other The hollow outer shaft co

13、ntacts the even-numbered gears, and the shaft inside it contacts the odd-numbered gears (see Fig.4-6b) DSG operates more smoothly than ordinary AT or MT, and it can deliver better fuel economy, as wellNew Words and Expressionsinterrupt intrpt vt 中断; 打断idle aidl vi 空转, 怠速mode mud n 模式; 方式continuously

14、 kntinjusli adv 连续不断地console knsul n 操纵台relatively reltivli adv 相当地; 相对地overdrive uvdraiv n 超速档fuel-efficient fjulifint adj 燃油效率高的mechanical mknikl adj 机械的hydraulic haidrlik adj 液压的harmony hmni n 协调New Words and Expressionsautomatically tmtikli adv 自动地accomplish kmpli vt 完成; 实现reverse rivs n 倒档neutr

15、al njutrl n 空档seamlessly si: mlisli adv 无缝地pulley puli n 带轮cone kun n 锥形盘odd-numbered dnmbd adj 奇数的, 单数的even-numbered ivnnmbd adj 偶数的in accordance with根据, 按照beregarded as被认为是Common Automobile Termschassis si n 底盘, 底架gearbox gibks n 变速器 (箱)gearshift iift n 变速杆collar kl n 结合套carrier kri n 行星齿轮架drive train传动系统, 驱动机构manual transmission (MT) 手动变速器automatic transmission (AT) 自动变速器continuously variable transmission (C