Automobile Transmission

Chapter Two Unit Two Automobile Transmission

Step I. Duty Report Step II. Review Review what they learnt in the last class why we need a clutch? the main function of a clutch basic ports of a clutch Recite the new words

Chapter Two Unit Two Automobile Transmission Step III. Reading material Ask the students read the whole text and get the main idea Discuss about the text Step IV. Automobile transmission New words: Check the pronunciation of the new words main usage of the words

Chapter Two Unit Two Automobile Transmission Step V. Exercise Ask the students translate some passages Ask the students describe the main units of the connecting rod and crankshaft, and their main function

Chapter Two Unit Two Automobile Transmission

Ring gear Planetary gear Planet carrier Sun gear

Chapter Two Unit Two Automobile Transmission

P － Parking 驻车 R － Reverse 倒 N － Neutral 空档 D － Drive 前进档 2(S) － Second 强制 2 档 1(L) － Low 强制一档

Chapter Two Unit Two Automobile Transmission CVT ＝ Continuously Variable Transmission （无级变速器）

Chapter Two Unit Two Automobile Transmission

Step VI. Dialogue A: May I ask you some questions about automobile transmission? B: Sure. Go ahead, please. A: What is the automobile transmission? B: The transmission is a speed and power changing device. That is, the transmission is used to change the ratio between engine rpm and driving wheel rpm. A: Is it possible for a vehicle without transmission to move forward?

Chapter Two Unit Two Automobile Transmission B: Yes, it is. Any vehicle without a transmission could be made to move but not smoothly. A: Why can ’ t it move smoothly? B: Because the vehicle could not get enough power to start. What ’ s more, if a vehicle had no transmission, its start would be slow, noisy and uncomfortable. A: Oh, I understand. So, in order for a vehicle to get enough power for its smooth start, a power ratio must be provided to multiply the torque of the engine. B: That ’ s right.

Chapter Two Unit Two Automobile Transmission A: Would you please tell me something about the transmission structure? B: OK. The transmission structure is not very complex. It contains a kind of compound gear train, and usually power is transmitted through more than one pair of gears. Structurally, the transmission is mainly composed of the transmission case, input shaft, output shaft, countershaft, driving gear, transmission fork, etc. A: Do you know how an automobile reverses its direction?

Chapter Two Unit Two Automobile Transmission B: Yes. To my knowledge, the transmission usually provides a reverse gear, which permits an automobile to reverse its direction. Moreover, a common transmission has gear arrangement of neutral position reverse gear first gear, second gear, third gear, etc. A: By the way, are there any different types of automobile transmissions? B: Yes, there are three basic types of transmissions such as the sliding gear type, the planetary type and the friction-disc type.