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 Рис. 1. Principle of Operation of the Four-Stroke Petrol Engine

1.intake - такт впуска 3. power — рабочий такт

2. compression — такт сжатия 4. exhaust — такт выхлопа

The exercises to be done after reading the text

Послетекстовые упражнения

Упражнение 5. Найдите в тексте абзацы, где идет речь о такте впуска, о такте сжатия, о рабочем ходе, о такте выпуска и переведите их на русский язык.

Упражнение 6. Выберите правильные по смыслу ответы на вопросы.

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?

1.It is called so because the fuel (the mixture) is burned…

a)directly inside the engine;

b)outside the engine.

2. The inlet stroke is called so because during moving down the piston…

a) the inlet valve opens to intake a charge of fuel into the cylin­der;

b)the inlet valve is closed and the mixture is compressed.

3.The compression stroke is a stroke..

a) when the inlet valve opens to intake a charge of fuel into the cylinder;

b) when the inlet valve is closed and the mixture is compressed.

4. On power stroke.

a)the spark plugs ignite the mixture, both valves are closed dur­ing its combustion;

b)the exhaust valve is opened and the residual gas flows through the exhaust valve into the atmosphere.

5.On the exhaust stroke...

a)the spark plugs ignite the mixture, both valves are closed dur­ing its combustion;

b)the exhaust valve is opened and the residual gas flows through the exhaust valve into the atmosphere.

6. It is done...

a)by means of pistons;

b)by means of the connecting rods.

Упражнение 7. Закончите предложения, выбрав правильный по смыслу вариант окончания.

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.

Упражнение 8. Прочтите диалог несколько раз, а затем разыграйте его в парах.

DIALOGUE АTracing a Fault

Nick: Peter, I know you are a good driver. I would like you to have a

look at my car.

Peter: What's wrong with your car?

N.: I don't know.

P.: Let me have a look. When did you have your plugs checked?

N.: Three days ago. I thought I had run out of fuel but the tank is half full.

P.: The carburettor is in order but the engine is misfiring. I guess

the battery has run down. It needs recharging.

N.: Too bad.

P.: Don't get upset about it. It won't take you long to have your

battery recharged.

N.: Do you really think so?

P.: I am sure of it. I advise you to have the engine greased.

N.: I'll follow your advice. Thank you, Peter.

P.: Don't mention it, Nick. I'm very sorry I couldn't help you.

N.: Well, you helped me to find the fault. Thanks a lot. Good-bye.

P.: See you later.

Упражнение 9. Переведите русские предложения на английский язык, а затем разыграйте диалоги в парах.

1. -Не знаю, что случилось с моей машиной.

-Let me trace the fault.

-Пожалуйста. Ты опытный водитель?

-Yes, I am. I have been driving а саг for fifteen years now. May be you have run out of fuel?

-Бак почти полный.

-When did you have your plugs checked?

-Вчера. Карбюратор тоже в порядке.

-В таком случае давай поедем до ближайшей ремонтной станции.

-Good idea. They will have the car fixed.

2.- Когда тебе починили машину?

-Last month. The engine is in good condition now. It was well

greased.

-Хорошо. Мне тоже надо чинить машину. Ослабли тормоза (The brakes are slack.) Аккумулятор разрядился (The battery has run down.)

-It can be easily done.

-Я рад это слышать.

3.- Какую машину ты хочешь купить?

-I want a second-hand car. Could you help me?

-С большим удовольствием.

-I hear there are good cars on sale 42nd Street.

-Я знаю этот магазин. Давай поедем туда.

-Good idea. If I choose a car there, I won't have to bother any more.

-Совершенно верно.

Упражнение10. Прочтите диалог и расскажите, о чем в нем идет речь.

DIALOGUE В

At the Repairing Shop

Client: Good afternoon! Can you help me? There is something wrong with the engine.

Master: Hi! What is wrong with it?

С.: I don't know. It wouldn't start. Maybe the pistons and valves are in disorder.

M.: Let's have a look! Well, they are quite right.

C.: And what about the crankshaft, or electric spark plugs. I know absolutely nothing about the operating cycle of the engine.

Just a moment. Don't worry! We shall check up all units and how they work together.

Some time later

M.: My God! There is no petrol in the tank. How can you move drive?

C.: Really? Oh, I have forgotten to fill in the tank! I beg your par­don to trouble you!

M.: No trouble, at all. You are welcome!

СЛОВАРЬ УРОКА

1.as a result - в результате

2.assume — предполагать

3.bottom dead center — нижняя мертвая точка

4. burn – гореть

5.by means of — посредством 6.charge of fuel - заряд топлива 7.combustion — сгорание 8.combustion chamber — камера сго­рания

9.compression stroke — такт сжатия(смеси)

10.connecting rod — шатун

11.convert— преобразовывать 12.crankshaft — коленчатый вал 13.cylinder — цилиндр

14. descend - спускаться, опускаться (опоршне)

15.describe— описывать

16.diesel engine — дизельный двигатель

17.directly - непосредственно

18.don't get upset — не расстраивайтесь

19.engine — двигатель

20.exhaust stroke — такт выпуска

22.follow sb's advice - последовать чье-му-л. совету

23. four-stroke cycle — четырехтактный цикл

24.fuel injection — впрыск топлива

25.have a look — взглянуть

26.heat — тепло

27.I guess — я полагаю

28.ignite — воспламенять

29.ignition — воспламенение

30.in order — в порядке (в исправном состоянии)

31.intake (inlet) stroke — такт впуска

32.internal combustion 33.engine—двигатель внутреннего сгорания

34.mixture — смесь

35.operating cycle — рабочий цикл

36. petrol engine — бензиновый двигатель

37.piston - поршень

38.power stroke - рабочий ход 39.pressure — давление

40.reach — достигать

41.recharge — подзарядить (аккуму­лятор)

42.reciprocating movement - возвратно-поступательное движение

43.residual gas - остаточный газ

44.rise – подниматься

45.rotary movement — вращательноедвижение

46.run down - сесть (об аккумуляторах)

47.run out of fuel — закончилось топливо

48.spark plug — свеча зажигания 49.stroke — ход (поршня)

50.tank — топливный бак

51.top dead center - верхняя мертвая точка

52.trace the fault - искать (проследить)неисправность 53.valve — клапан

Unit Four

Text: Chassis

Dialogue: Transmission Mechanism

Предтекстовые упражнения