6. Answer the questions:

1) Where does the heat come from?

2) How is the engine kept cool?

3) What causes the engine to wear?

4) How is the engine protected from the excessive wear?

7. Make Participle I and Participle II from the following words and make sentences with them:

to drive, to move, to use, to change, to contain, to turn, to cover

Unit 8 Transmission system

1. Memorize the new words and word-combinations:

1.change gear

2.clutch

3.rear axle gear

4.revolution

5.differential gear

6.gearbox

7.lay shaft

8.driving shaft

9.to slip

10.fixed gear

11.crown wheel

12.reverse

коробка передач

муфта

головна передача

обертання

диференційна передача

коробка передач

проміжний вал

ведучий вал

ковзати

зубчате колесо, шестерня

коронна шестерня

зворотній хід

2. Choose the right version:

1) There (were, will be, have been) several bad accidents at this corner recently.

2) There (will be, were, are) lights in the middle of the crossing.

3) They (test, will test, tested) the new engine last month.

4) He (cuts, will cut, cut) himself while he (was repairing, repair, was repaired) his car.

5) The light (changed, has changed, changes) just fron green to red.

3. Read and translate the text. Transmission system

The transmission system carries (transmits) the movement of the crankshaft to the wheels. It has three main parts: the change gears, the clutch and the rear axle gears. A gear is a strong steel wheel with teeth. If a small gear with 25 teeth turns twice, it will turn a gear with 50 teeth once. This is a low gear. If a large gear with 50 teeth turns once, it will turn a gear with 25 teeth twice. This is a high gear. Gears can have as many teeth as are needed.

The crankshaft of a car engine can turn as fast as 6,000 times a minute. One turn is a revolution. So that is 6,000 revolutions per minute. This speed is too great to transmit straight to the wheels. It is made less by two things: the change gears and the differential gears in the back axle.

The change gears. In the gearbox there are three shafts. a) The driving shaft is turned by the crankshaft. It has a fixed gear wheel near its end. b) The driven shaft leads to the back axle. On this shaft there are two gears. One gear is larger than the other. These gears can move along the shaft in grooves. They can move backwards and forwards. They are moved by a gear lever. c) The lay shaft. Four gears of different sizes are fixed on this shaft. The largest always meshes with the gear on the driving shaft. So, when the engine is running the lay shaft must be turning. It must turn slowly than the driving shaft. Its gear is larger. The gearbox is about half-full of oil.

First gear. The large gear on the driven shaft meshes with the smaller forward gear on the lay shaft. And the wheels turn slowly. This gear is used to start the car moving.

Second gear. The smaller gear on the driven shaft meshes with the second largest gear on the lay shaft. The gears are almost the same size.

Top gear. The driving shaft joins straight on the driven shaft. The car is now moving very fast. There is little difference berween the engine speed and the speed of the wheels. If the car has to slow down, the driver will have to change to a lower gear.

Neutral gear. The driving shaft is turning but it is not transmitting any movement to the driven shaft. The gears are not meshing. The engine is running but it is not turning the car wheels. This gear is used when the car stops for a short time, like at traffic lights. It is also used when the engine is first started.

Reverse gear. The fourth gear on the lay shaft meshes with the larger gear on the driven shaft. It does this through the smaller third gear. This gear reverses the movement of the driven shaft.

The clutch helps when the driver changes gear. Strong springs press it against the flywheel. These springs push away the cover plate. Round the inside of the clutch plate there is rough material. This does not slip easily. So, when the flywheel turns, the clutch plate turns too. This movement goes to the gears. When the clutch pedal is pushed down, the clutch plate is pulled away from the flywheel. There is a space. The crankshaft is turning but the movement is not going to the gears or the wheels. Now the gears can be changed. When the clutch pedal is let out, the springs push the clutch plate against the flywheel again. The movement of the crankshaft now goes through the gears to the wheels.

Rear axle gears

1. From the change gears the movement is transmitted to the back axle by the propeller shaft. At the back end of this shaft there is a fixed gear.

2. The back axle has two halves. A strong gear is fixed to each half.

3. A strong box covers the strong gears (bevel wheels). This box turns when the axles turn.

4. To one side of this box is fixed a large gear. When it turns, it turns the box and the axles.

5. The pinion meshes with the crown wheel. When the pinion turns, it turns the crown wheel and the box and the axles.

Round the inside of the box are fixed four small gears (differential pinions). The differential pinions allow the two wheels to turn at different speeds when the car is turning.