Principle of Operation of the Four-Stroke Petrol Engine

The internal combustion engine is called so because fuel is burned directly inside the engine itself. Most automobile engines work on a 4-stroke cycle. A cycle is one complete sequence of 4 strokes of the piston in the cylinder. The operating cycle of the four-stroke petrol engine includes: inlet stroke (intake valve opens), compression stroke (both valves closed), power stroke (both valves closed), exhaust stroke (exhaust valve is opened).

To describe the complete cycle, let's assume that the piston is at the top of the stroke (top dead center) and the inlet and the exhaust valves are closed. When the piston moves down the inlet valve opens to intake a charge of fuel into the cylinder. This is called the inlet (intake) stroke. On reaching the lowest position (bottom dead center) the pis­ton begins to move upward into the closed upper part on the cylinder, (he inlet valve is closed and the mixture is compressed by the rising piston. This is called the compression stroke. As the piston again reaches the top dead center the spark plugs ignite the mixture, both valves be­ing closed during its combustion. As a result of burning mixtures the both valves be­ing closed during its combustion. As a result of burning mixtures the gases expand and great pressure makes the piston move back down the cylinder. This stroke is called the power stroke. When the piston reaches the bottom of its stroke, the exhaust valve is opened, pressure is re­leased, and the piston again rises. It lets the burnt gas flow through the exhaust valve into the atmosphere. This is called the exhaust stroke which completes the cycle. So the piston moves in the cylinder down (intake stroke), up (compression stroke), down (power stroke), up (ex­haust stroke).

The heat released by the fuel is transformed into work so that the reciprocating movement of the pistons is converted into rotary move­ment of a crankshaft by means of connecting rods.

1 - intake 2 - compression 3 - power 4 - exhaust

  1. intake - такт впуска 3. power — рабочий такт
  2. compression — такт сжатия 4. exhaust — такт выхлопа


Answer the questions:

1. Why is the engine called the internal combustion engine?

2. What stroke is called the inlet one?

3. What is a compression stroke?

4. What takes place in the cylinder on power stroke?

5. What takes place on the exhaust stroke?

6. By means of what is the reciprocating movement of the pistons converted into rotary movement of a crankshaft?

Choose the right variant:

1. The internal combustion engine is called so because fuel is burned…

a) outside the engine; b) inside the engine.

2. On the inlet stroke.............

a) the intake valve opens; b) the intake valve is closed; c) the intake and the exhaust valves are closed.

3.On the compression stroke...............

a) the intake valve opens; b) the intake valve is closed; c) the intake and the exhaust valves are closed.

4.On the power stroke...........

a) the intake valve opens; b) the intake valve is closed; c) the intake and the exhaust valves are closed.

5.On the exhaust stroke.............

a) the exhaust valve opens; b) the intake valve is closed; c) the intake and the exhaust valves are closed.

Translate new words into Kazakh and learn them:

as a result assume bottom dead center burn by means of charge of fuel combustion combustion chamber compression stroke connecting rod convert crankshaft cylinder descend describe diesel engine directly engine exhaust stroke four-stroke cycle fuel injection top dead center trace the fault valve have a look heat ignite ignition intake (inlet) stroke internal combustion engine mixture operating cycle petrol engine piston power stroke pressure reach recharge reciprocating movement residual gas rise rotary movement run down run out of fuel spark plug stroke tank  


2. Grammar:

Present Continuous Past Continuous Future Continuous
I am reading a newspaper I was reading a newspaper when he came I shall be reading a newspaper when he comes.
Мен газет оқып отырмын Ол келгенде мен газет оқып отырдым Ол келгенде мен газет оқып отырамын

Exercise 1: Open the brackets

1. We could not go out because it (to rain) hard since early morning. 2. She (to teach) at our school for twenty years now. 3. Ring me up as soon as you (to come) home. 4. He (to begin) to write his composition at three o'clock. It is already eleven, and he still (to write) it. He says he (to finish) it by twelve. 5. We (to help) our librarian to put the books in the right order for three days already, but we (to arrange) only half the books. 6. What you (to do) when I (to come) in? 7. When I (to come) to his house, they (to tell) me that he (to leave) an hour before. 8. On checking up his answers he (to find) out that he (to make) several mistakes. 9. When I (to leave) home, the snow already (to stop), but a strong wind (to blow). 10. You (to read) this book? — Yes, I (to read) it. I (to think) it (to be) very interesting. 11. What the children (to do) now? — Oh, they (to play) the new board game which I (to buy) for them the day before yesterday. 12. They (to reach) the corner of the street by now and (to stand) at the bus stop. 13. After we (to walk) about two hours, we arrived at a picturesque glade covered with fresh grass.

Exercise 2: Open the brackets

1. At last the librarian (to give) me the book which I (to wait) for during two months. I was very glad. I (to go) home and (to begin) reading it at once. 2. Don't speak to him: he (to be) very busy, he (to do) some very urgent work. 3. I did not want him to go there: I (to be) afraid that something (to happen). 4.1 did not notice that my watch (to stop), and when I (to arrive) at the station, my train (to leave) and I (to have) to ask when the next train (to come). 6. He (to wait) for fifteen minutes when at last he (to see) her at the end of the platform. 6. By the end of the year he (to read) about two hundred pages. 7. We were happy when the sun (to rise), for the night (to be) very cold. 8. Where you (to put) my dictionary? I cannot find it anywhere. 9. I (not yet to fall) asleep when the telephone (to ring). 10. What you (to do) from six till nine yesterday? 11. The children (to play) here at eleven o'clock, but now they (to go) home. 12. Go to see your old grandfather as soon as you (to arrive) in Novgorod. 13. You always (to spend) summer at the seaside? — Yes, as a rule. Last summer I (to go) to the mountains, but I (not to find) the rest there as pleasant as near the sea. 14. When they returned, they (to tell) us many interesting things which they (to see) during their journey. 15. When I (to leave) home, it (to rain).


Week 3

Tasks / Тапсырмалар:

1. Dialogue “Meeting”

2. Grammar: Perfect tenses (revision)


1. Read, translate and learn the dialogues:

I. Nick: Hullo, Boris!

Boris: Hullo, Nick. How are things?

N.: Perfectly well, thank you. I entered the automobile construc­tion college.

В.: That's nice, what will you become after graduating from the college?

N.: I'll become a technician and deal with manufacturing new cars.

В.: Why did you choose this profession?

N.: I enjoy learning about a car. I enjoy working with metal. And most of all I enjoy being able to construct cars.

В.: Do you enjoy the course?

N.: Yes, of course.

В.: Tell me about your profession in detail, please?

N.: With great pleasure. As you know an automobile must be safe, have smooth acting clutch, silent gears, excellent brakes and steering system. And in order to achieve these qualities a lot of work must be done.

В.: Thank you very much for your information. I believe you like your profession very much.

N.: Oh, yes, very much, indeed.


II. Anton: Where do you study?

Boris: I study at the automobile construction college.

A: Whom does the college train?

B: It trains specialists for the automobile industry.

A: Why did you decide to become a technician?

B: I enjoy working with machines. I enjoy learning about a car. I understand every part of it.

A: What can you tell me about the car?

B: Well, the car of today must be rapid in acceleration; it must have dependable clutch, brakes, and steering system, be stable on the road and have pleasant appearance.

A: Do you enjoy the course?

B: Yes, very much. I have learned a lot of things. For example, I know that the production of the car comprises five phases.

A: What are they?

B: They are designing, working out the technology, laboratory tests, road tests, mass production.

A: And why are laboratory and road tests needed?

B: The cars are subjected to tests in order to meet up-to-date de­mands.

A: And what are these demands?

B: They are high efficiency, long service life, driving safety, ease of maintenance and so on.

A: I think you will become an expert in automobile engineering.

B: I'll try. The cooperative plan of an academic program with prac­tice at a plant will help me to become a good specialist.


2. Grammar:

Present Perfect Past Perfect Future Perfect
I have written the letter, you may post it. I had written the letter by five o clock. I shall have written the letter by five o clock.
Мен хат жазып болдым, жеберуіңізге болады. Мен хатты сағат беске таман жазып болдым. Мен хатты сағат беске таман жазып боламын.

Exercise 1: Open the brackets

1. Our train starts late in the evening, so if you (to come) at seven o'clock, we still (to pack) our luggage. 2. When you (to see) him last? 3. I (to meet) him when he (to walk) across the park. 4. You ever (to act) on the stage? — Why, yes, that's what I (to do) for the last six years. 6. Don't enter the bedroom! The child (to sleep) there, and he always (to wake) up when somebody (to open) the door. 6. Where is your luggage? — I (to leave) it at the station. I (to take) it tomorrow when Nick (to come) to help me. 7. I (to read) about an hour when'he (to come). 8. The play (not yet to begin) and the people (to talk) in the hall. 9. One night a little swallow (to fly) over the city. His friends (to fly) away to Egypt six weeks before, but he (to stay) behind. 10. What you (to do) these three months? 11. Yesterday I (to buy) a new pair of gloves, as I (to lose) the old ones. 12. We (to walk) in silence. He already (to tell) me all that (to be) interesting about himself, and I (to have) nothing to tell him. 13. The moon (not to rise) yet, and only two stars, like two distant lighthouses, (to shine) in the dark blue sky.


Exercise 2: Open the brackets

1. What you (to read)? — I (to read) a magazine. — How long you (to read) it? — I (to read) it for half an hour. 2. She (to live) in Moscow for ten years when her sister (to come) to live with her. 3. Our teacher (to come). Now he (to speak) with our monitor. 4. They (to speak) when I (to look) at them. 6. What you (to do) here? — I (to prepare) for my report. — How long you (to prepare) for it? — Oh, I (to work) since morning. 6. He (to teach) at school for five years when the war (to break) out. 7. She (to study) English since last year. 8. You ever (to be) to London? — Yes, I (to be) there last summer. 9. What your friend (to do) now? — She (to have) dinner. She usually (to have) dinner at this time. 10. I (to buy) a new dress. I (to show) it to you tomorrow when you (to come) to my place. 11. So you begin working tomorrow! And who (to take) care of your children when you (to go) to work? 12. Hello, Peter! Where you (to go)? — I (to go) to the library. 13. I (to walk) about an hour when I (to see) a little house not far from the river. 14. When he (to read) the newspaper, he (to give) it to his brother. 15. He (to leave) for Rostov in 1990 and since then he (to live) there. 16. At this time tomorrow we (to discuss) your report. 17. Now she (to read) the book which I (to give) her yesterday.


Week 4

Tasks / Тапсырмалар:

1. Text “Chassis”

2. Grammar: Reported speech

Read and translate the text


The main units of the chassis are: the power transmission, the run­ning gear and the steering mechanism. The power transmission includes the whole mechanism between the engine and the rear wheels. This entire mechanism consists of the clutch, gearbox, propeller (cardan) shaft, rear axle, final drive, differential and axle shafts.

At the front end of the car is the engine. On the back of it is the flywheel. Behind the flywheel is the clutch. The clutch is a friction de­vice connecting the engine with the gears of the gearbox. The main function of the gearbox is to change the speed of the car.

The power is always transmitted by the cardan shaft to the live back axle. The final drive reduces the high speed of the engine to the low speed of the driving wheels. The differential enables the driving wheels to turn at different speeds which is necessary when turning the car. The foundation of the automobile is the frame to which different chassis units are attached.

The rear axle is capable of moving up and down about the frame. The rear axle is an important part of the transmission. It carries the greater portion of the weight of the car.

The steering mechanism is designed for changing the direction of the car.

The brakes are used for stopping the car, for decreasing its speed and for holding the car position.

Answer the questions:

1. What main units does the chassis consist of?

2. Where is the engine located?

3. Where is the flywheel fixed?

4. Where is the clutch placed?

5. What is the gearbox designed for?

6. By what shaft is the power transmitted to the back axle?

7. What does the rear axle do?

8. What is the function of the differential?

9. What purpose is the steering system designed for?

10. What is the function of the brakes?

Translate new words into Kazakh and learn them:

unjust attach be capable breather channel check decrease the speed driven wheels driving wheels engine crankshaft fastening bolts fit properly flywheel frame free travel gear lever greater portion of the car weight hold the car position housing incomplete disengagement level within the range fastening bolts fit properly malfunction mount power transmission rear wheels run out running gear self-demeshing of gears springs steering system steering wheel) support tighten torque tractive effort travelling speed trouble trunnion cross universal-joint forks  


2. Grammar:

Reported speech

Басқа біреудің айтылған немесе айтылуға тиістісөзінің ешбір өзгеріссіз жеткізілген түрін төл сөз дейміз.

The say: «We are always busy on Monday”

The monitor says: “Ahmetov is absent today”

Автор бөгде сөзді өзінше өзгертіп,тек сөздің жалпы ой желісін,мазмұнын сақтаса,ол төлеу сөз болады.

They say that they are always busy on Monday

The monitor says that Ahmetov is absent today.

I said: “I like apples”   I said that I liked apples.  
I said: “It is snowing.”   I said that it was snowing.  
I said: “John has a lesson this morning.”   I said that John had a lesson that morning.  
I said: “I’ll go to the cinema”   I said that he would go to the cinema.  
I said: “She can dance well.”   I said that she could dance well.  

Exercise 1:A. Change the sentences into reported speech. Tell your friend what Miranda says.

Example: Miranda says, "I work for a small publishing house." — Miranda says (that) she works for a small publishing house.

1. I'm going to work in England next year. 2. I'm their marketing manager. 3. The company has opened an office in London. 4. Up till now I've been very successful in my career. 5. I've been chosen to run the new office in London. 6. I'm studying English in the evenings. 7. I don't have much time to enjoy myself. 8. I haven't had lunch with a friend for ages. 9. I hope my friends will come and visit me in London. 10. I went there last week with my secretary. 11. We didn't have much time for sightseeing. 12. I have to get back to work now.


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