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The upper end consists of a combustion or “clearance” space, in which, the ignition and combustion of the charge takes place.

Cylinder size. Before deciding on the cylinder size and the number of cylinders the engineer will need to know how much power is wanted.

For example, if the need is for 100 hp (horse power), it can be developed by one cylinder engine, having a cylinder of sufficient size. Or the same power can be developed by a 16-cylinder engine, having much smaller cylinders.

If the engine is to be used for a stationary power plant, the choice might be one or two cylinders.

If the engine is intended for use in automobile, it would be better to use 6 or 8 cylinders of smaller size. The smaller cylinders would have smaller pistons, rods etc., and as the parts are much lighter the engine can operate at higher rotational speed for a gain in power.

Of course it must be remembered, that many improvements have been made in engine design in the past years. Today we often in about four times the power from a given size engine that we did thirty years ago. The bore, of the engine is not the sole determining factor in the amount of power that the engine will produce. Neither is the speed at which the engine operates is the determining factor.

Many things need to be taken into consideration. Piston displacement is a reliable figure for indicating the potential power output of the engine. Piston displacement is the number of cubic inches of space, displaced by the cylinder away from the crankshaft. The cubic inch displacement of an engine can be obtained mathematically from the dimensions.

Задание 5. Закончите следующие предложения.

1.The fundamental parts of the engine are...

2.Cylinder is a cylindrical barrel in which...

3.The upper end of the cylinder consists of a combustion space in which...

4.If the engine is to be used for a stationary power plant the choice might be…

5.As the parts of the engine are lighter, the engine can operate at...

6.Piston displacement is...

Задание 6. Переведите на английский язык, используя текст.

1.Коленчатый вал - одна из основныхчастей двигателя.

2.Этот двигатель предназначен для стационарной силовой установки.

3.Следует помнить, что было сделано много усовершенствований в конструировании двигателей.

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4.Многие факторы следует принимать во внимание.

5.Размер цилиндра зависит от требуемой мощности двигателя.

Задание 7. Найдите ответ, соответствующий содержанию тек-

ста.

1.What are the fundamental parts of the engine?

2.What is the cylinder?

3.What is known as the stroke-bore ratio?

4.How many cylinders are usually used for the automobile engine?

5.On what does the power produced by the engine depend?

Задание 8. Посмотрите на схему на с. 204 и скажите, к какому механизму относятся основные части двигателя. Расскажите об этом механизме, используя схему.

При ответе используйте следующие выражения:

as far аs I know... ; it is known, that... ; it should be noted... ; it is worth mentioning... ; it is a well - known fact...; the problem is ... .

Текст 8

Задание 1. Прочтите текст, стараясь понять содержание.

PLASTIC ENGINE PARTS

To decrease an automobile's weight, and thus improve its fuel efficiency, more and more parts are now made of plastic— but usually not critical engine components. Because of high stress and heat most engine parts are still made of metal. Now, in Britain, an intake manifold — the engine-block attachment that feeds air and fuel from the carburetor to the cylinders — has been molded from plastic. Its developers are Fibeiglass, Ltd., of St. Helens, Merseyside, BTR Permali RP, Ltd., of Gloucester, and Ford Motor Co. Ltd., of Essex. The new manifold is believed to be the first major plastic engine component ever to be designed for production automobiles. It is made by polyester compound — called X52 — and is shaped exactly like an aluminum manifold currently used on the Ford Cortina's 1.3-liter engine. Since this part has a series of intricate, twisting interior chambers, a new molding technique had to be devised. The trick is to form the plastic around metal cores inside a mold. Once the manifold is set, or cured, it is placed in a hot oil bath that melts the metal cores, leaving the required hollow chambers.

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The 21/2 -pound plastic manifold weighs 25 per cent less than a metal one. But its importance goes beyond this minor reduction. According to its developers, the manifold's special plastic compound and the new molding technique may represent breakthroughs leading to additional lightweight engine parts, as well as products for other industries.

Задание 2. Составьте план текста.

Задание 3. Изложите содержание текста.

Текст 9 TYPES OF FUELS

There are three basic types of fuels for motor vehicles. There is diesel fuel, there is petrol and there is two-stroke mixture. Most motorcycles have twostroke petrol engine. There are motorcycles with four-stroke petrol engines; there are no motorcycles with diesel engines.

A few cars have diesel engines. There are also few cars with two-stroke engines but most cars have four-stroke petrol engines. Most lorries have diesel engines. There are a few lorries with four-stroke petrol engines but there are no lorries with two-stroke petrol engines.

There is a lot of carbon (about 85%) in diesel fuel. There is also a lot of carbon in petrol. There is also a little sulphur (about 1%) in diesel fuel but there is no sulphur in petrol.

Two-stroke mixture is about 95% petrol and 5% oil. There is no oil in the fuel for four stroke engines.

Задание 1. Переведите текст со словарём. Выпишите названия веществ, входящих в состав топлива различного типа. Заполните таблицу 2.

Таблица 2

petrol

two-stroke mixture

Задание 2. Опишите классификацию двигателей внутреннего сгорания в зависимости от типа топлива.

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3 4

5

1

Рис.8

Задание 3. Заполните пропуски в следующем тексте.

Задание 4. Просмотрите текст и дайте определение следующим понятиям:

stroke, Т.D.С., B.D.C., four-cycle engine.

The activities that take place in the engine cylinder can be divided into four stages, or strokes. "Stroke" refers to the piston movement. The upper limit of piston movement is called top dead centre or T.D.C. The lower limit of piston movement is called bottom dead centre or B.D.C. A stroke constitutes piston movement from T.D.C. to B.D.C. or from B.D.C to T.D.C. In other words the piston completes a stroke each time it changes direction of motion. Where the entire cycle of events in the cylinder requires four strokes (two crankshaft revolutions), the engine is called a four-stroke-cycle engine or a four-cycle engine. The four strokes are: intake, compression, power and exhaust.

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Задание 5. Переведите таблицу 3. Техническая информация (рис. 9) поможет Вам.

Таблица 3

The crankshaft turns through half a revolution (1800 ) during each

stroke.

Swept volume: this is the volume of the space between t.d.c. and b.d.c.

Clearance volume: this is the volume of the cylinder space above

Bore: the internal diameter of a cylinder.

Engine capacity: the swept volume of all engine cylinders added together.

crankshaft

Рис.9

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Задание 6. Заполните пропуски недостающими терминами.

Задание 7. Пользуясь таблицей 3 и рис. 8, заполните пропуски в следующем тексте:

a. The Intake Stroke.

On the intake ... the intake valve is opened. The piston is moving down, and a mixture of ... and vaporized gasoline is being drawn into the ... through the

... .... The mixture of ... and air is delivered to the ... by the fuel system.

b. The Compression Stroke.

After the piston reaches ... or the lower limit of its travel, it begins to move upward and at this instant the ... ... closes. The other valve is also ... so that the cylinder is sealed. The piston moves ... compressing the ... .

This creates a fairly high pressure within the ... .

c. The power Stroke.

As the piston reaches ... or the upper limit of its travel, an electric spark is generated at the cylinder spark plug. The spark ignites ... of gasoline vapor and

... . The burning gases expand and force the piston downwards again. The power

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