6. Translate the verbs formed by conversion:

work - to work, block - to block, size - to size, wall - to wall, spring - to spring, ring - to ring, pin - to pin

Unit 19

Valves and camshaft

1. Memorize the new words and word-combinations:

1.set

2.to arrange

3.by means of

4.chain

5.gear

6.angle

7.stem

8.accuracy

9.timing

набір

розташовувати

за допомогою

ланцюг

передача

кут

шток

точність

установка,регулювання часу

2. Choose the right translation:

1. inlet valve

2. exhaust valve

3. coil spring

4. valve stem

5. rocker arm

6. valve spring

7. cylinder walls

8. push rod

9. timing chain

10. petrol-air mixture

11. oil pump

a) клапане коромисло (важіль, що гойдається)

b) пружина клапану

c) стінка циліндру

d) стрижень клапану

e) спіральна пружина

f) ланцюг приводу розподільного механізму

g) штанга штовхача

h) масляний насос

i) паливно- повітряна суміш

j) випускний клапан

k) впускний клапан

3. Read and translate the text.

Valves and camshaft

There are two valves to each cylinder: one inlet and one exhaust. The inlet valves let the petrol / air mixture into the engine while the exhaust valves allow the burnt gases after combustion to escape from the engine. Both sets of valves have to be arranged, to open and close at just the right moment. This is done by means of a camshaft.

The camshaft is driven by a chain or gear at half the speed of the crankshaft. It has specially shaped projections, known as cams, set at varying angles. There are as many cams as there are valves, and as the camshaft revolves, each cam causes its corresponding valve to open. Then, as the cam moves further round, a coil spring fitted round the valve stem forces the valve to shut, and it is then ready to open again next time the cam comes round.

During every revolution of the camshaft all the valves open and close once. In a fast-moving car fitted with a four-cylinder engine, each valve opens and closes between thirty and forty times every second. This gives you some idea of the speed of operation and the accuracy needed to obtain correct timing.

4. Answer the questions:

1) What is the purpose of the inlet valve?

2) What is the purpose of the exhaust valve?

3) What is the function of the camshaft?

5. Say with one word:

1) valve that admits fuel mixture into the cylinder of an engine

2) valve that opens to allow exhaust gases from the cylinder to pass to the exhaust manifold

3) rigid metal link that transmits power between a piston and a crankshaft

4) shaft that employs a number of cams which operate the valves and some of the other moving parts of an internal-combustion engine