Principle of Operation of the Four-Stroke Petrol Engine

Тема:Двигатели

T: Good afternoon, students! Sit down, please. I am very glad to see you. Today at our lesson we shall read and talk about engine. Answer my questions, please. For each right answer I’ll give you a small red card. The students who will have many cards will get good marks. Listen to me attentively!

- Is the word “engine” an English word?

- What language did this word come from?

- What does the word “engine” mean?

- Is engine a clever device? Why? Does it produce energy for making the car move?

- What engines do you know?

Today we’ll speak about an internal combustion engine. What engine is called internal combustion engine? Why it is called so? Can you answer this question?

You may speak Russian. (Студенты дают объяснение на русском языке)

Do you know when and where was the first engine invented? Who was the inventor of the internal combustion engine?

Dima has prepared a presentation about the history of internal combustion engine.Let him show his presentation and listen to him!

Answer my questions:

- What kind of engines was the first engine? (It was steam engine)

- Who invented the first steam engine?

- Who invented the first internal combustion engine? (Etienne Lenoir)

- Who invented the first four-stroke engine? (Nicolaus Otto)

- What are the main parts of internal combustion engine?

Look at this poster and name the main parts of engine!

Listen to the text. Try to understand what this text is about and what words are known for you.

After listening the text answer my questions:

- What words in the text do you know?

- What is the English for:

нижняя мёртвая точка

верхняя мёртвая точка

ход

поршень

такт впуска

такт выпуска

рабочий ход

воспламенение

сгорание

вращательное движение

свеча зажигания

впрыск топлива

- What is the text about?

Listen to this text again and be ready to answer the following questions:

- What is a stroke?

- What processes occur during the cycle?

We’ll see a small film about these processes.

Find exercise 4, read the sentences aloud and translate them

Упр. 4 прочитать предложения и перевести их на русский язык.

Read the text out one by one. Translate this text.

Answer the following questions. Ex 6.

5(г) Look at this poster and describe the processes which occur inside the engine.

Приложение

Ex 4.

Translate the sentences into Russian

1. During the inlet (intake) stroke the inlet valve opens and a charge of fuel (mixture) flows into the cylinder.

2. During the compression stroke the inlet valve is closed and the fuel is compressed by the rising piston.

3. During the power stroke both valves are closed, pressure rises in the combustion chamber, and the spark ignites the mixture.

4. During the exhaust stroke the exhaust valve is opened, pressure is released and the residual gases flow into the atmosphere through the exhaust valve.

TEXT

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, compression stroke, power stroke, exhaust stroke.

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, (the 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).

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

Principle of Operation of the Four-Stroke Petrol Engine

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.