angls

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quickly to attain operating temperatures, at which time the cooling system begins to function.

Two general types of cooling system are used, air cooling and liquid cooling. Automotive engines now employ liquid cooling, although some special engines for airplanes, motocycles, etc., are air cooled.

AIR-COOLED ENGINES

In the air-cooled engines the cylinders are usually semi-independent. and are not grouped in a block. They are so placed that an adequate volume of air can circulate around each cylinder, absorbing heat in passing. Radial aircraft engines1, in which the cylinders are placed in a circle around the crankshaft, represented this design. Each cylinder normally has a series of ribs or fins2 so that the cooling area is considerably increased.

LIQUID-COOLED ENGINES

In liquid-cooled engines provision is made3 to circulate liquid (usually water to which antifreeze solution is added during cold weather)

around the cylinders where it absorbs heat. The water is then conducted through a radiator in which the heat in the water is passed on to air that is flowing through the radiator. The water passages, size of radiator, and other details are so designed as to maintain the cylinder walls, head, and pistons at efficient operating temperatures.

WATER JACKETS

Just as we might put on a sweater or jacket to keep warm on a cool day, so are water jackets placed around the engine cylinders. There is this difference: water jackets are designed to keep the cylinders cool. Early engines with separately cast cylinders used jackets made of sheet metal that were attached to the cylinders after the cylinders had been completed and assembled to the engine block.

In such cylinder blocks the water jackets are cored out4 so that water can circulate freely around the cylinders as well as around the valve openings.

WATER-DISTRIBUTING TUBES

On many engines, water-distributing tubes are used to direct the flow of cooling water as it enters the water jackets from the radiator. Valve seats and valve guides5 must be kept within a safe temperature range, and, by

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directing a flow of cooling water at them through distributing tubes and nozzles, they are adequately cooled.

ЗАВДАННЯ 1

Дайте відповіді на запитання:

1.What is the purpose of the engine cooling system?

2.What temperature is generated in the cylinders during each combustion process?

3.What temperature must the cylinder walls have?

4.What happens if temperatures higher than 400°F occur?

5.What lowers engine thermal efficiency?

6.What general types of cooling system are used?

7.In what way are the cylinders in air-cooled engines placed?

8.What has each cylinder?

9.In what way are the liquid-cooled engines cooled?

10.In what way are the operating temperatures of the cylinder walls, head and piston maintained?

11.For what purpose are water-jackets designed?

ЗАВДАННЯ 2

Складіть речення із словосполучень:

combustion, mixture, engine, heat, to design, to prevent, absorb, volume, liquid, to distribute, pump, to consist, shaft, to connect, to support, to drive, belt, to transmit.

ЗАВДАННЯ 3

Зробіть лексико-граматичний аналіз речень:

1. Early engines with separately cast cylinders used jackets made of sheet metal that were attached to the cylinders after the cylinders had been completed and assembled to the engine block.

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2.The water is then conducted through a radiator in which the heat in the water is passed on to air that is flowing through the radiator.

3.The water being hotter than surrounding metal shell of the radiator gives up part of its heat to the radiator.

4.The water is kept in continual circulation, so that it is constantly transferring heat from the engine to the air.

ЗАВДАННЯ 4

Перекладіть на англійську мову:

1.Існує два основні типи систем охолодження: повітряна та рідинна.

2.Водяна рубашка конструюється для того, щоб охолоджувати циліндри.

3.У радіаторі знаходиться багато трубок, по яким тече вода.

4.Камера згорання оточена водяною рубашкою, по якій тече вода.

ЗАВДАННЯ 5

Поставте дієслова у потрібний час:

1.She (to forget) to push down the clutch pedal before she (to change) the gear.

2.I (to shout) to the taxi to stop, but it (to drive) too fast.

3.He (to propose) me to increase the speed and in five minutes we (to arrive) to the place.

4.I will go home after I (to finish) repairing the car.

5.They (to drive) at about fourty miles an hour when the policeman (to stop) them.

6.I shall cash the cheque as soon as the bank (to open)

7.Tomorrow at this time we (to come) to Kiev.

8.If he (to be) still working when you (to come), advise him to go to bed.

TEXT B

COOLING SYSTEM

The burning of the fuel-air mixture in the engine cylinders produces a great deal of1 heat. Temperature of several thousand degrees2 Fahrenheit is generated in the cylinder each combustion process. Some of this heat is carried away from the engine by the lubricating oil.

The cooling system provides a means for carrying the excessive heat away from the engine3 and exhausting it into the air. Circulating water is used as

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the conducting medium4. The combustion chambers of the engine are surrounded with water jacket through which water can flow.

A water pump draws the water from the bottom of the radiator, through the water jackets and back to the radiator. The radiator has numerous small water passages through which the water must flow. The water being hotter than surrounding metal shell of the radiator gives up part of its heat to the radiator. An engine fan pulls a powerful blast of air5 through many air passages in the radiator, and the heat that is absorbed by the metal shell of the radiator is thus transmitted to the passing air, After the water has been cooled by its passage through the radiator, it is pumped back through the water jackets6 around the combustion chambers in the engine, where it absorbs more heat. The water is kept in continual circulation, so that it is constantly transferring heat from the engine to the air.

ЗАВДАННЯ 1

Випишіть з тексту речення, у яких маєтьсягерундій, віддієслівний іменник, дієприкметник теперішнього часу. Знайдіть іх функції і засоби перекладу на українську мову.

ЗАВДАННЯ 2

Дайте відповіді на запитання:

1.What is the purpose of the cooling system?

2.What temperature is generated in the cylinders during each combustion process?

3.What is the combustion chamber surrounded with?

4.What is the purpose of the water pump?

5.What is the purpose of the engine fan?

6.In what way is the heat transmitted to the passing air?

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ЗАВДАННЯ 3

Знайдіть у правому стовбці еквіваленти слідуючих українських

ЗАВДАННЯ 4

Поставте відповідну цифру до кожного терміну, даному під малюнком:

Water pumps are usually of the impeller type and are mounted at the front end of the cylinder bloc between the block and radiator. The pump consists of a housing, with a water inlet and outlet, and an impeller. The impeller is a flat plate mounted on the pump shaft with a series of curved blades or vanes. When the impeller rotates, the water between the blades is thrown outward by centrifugal force so that it is forced through the pump outlet into the cylinder block. The pump inlet is connected by a hose to the bottom of the radiator, and water from

the radiator is drawn into the pump to replace the water forced through the outlet.

The impeller shaft is supported on one or more bearings, and a seal is used to prevent water from leaking out around the bearing. The pump is driven by a belt to the drive pulley attached to the front end of the engine crankshaft.

ENGINE FAN

The engine fan usually is mounted on the water-pump shaft and is driven by the same belt that drives the pump and the generator. The purpose of the fan is to provide a powerful draft of air through the radiator to improve engine cooling. The fan usually has from two to six blades that in rotating pull air through the radiator. Some applications are equipped with a fan shroud that improves fan performance. The shroud increases the efficiency of the fan, since it assures that all air pulled back by the fan must first pass through the radiator.

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BELTS

Most belts are of the V or vee type. Friction between the sides of the belt and the sides of the grooves in the pulleys causes the driving power to be transmitted through the belt from one to the other pulley. The vee-type belt provides a substantial area of contact so that considerable power may be transmitted, and the wedging action of the belt as it curves into the pulley grooves aids in preventing belt slippage.

ЗАВДАННЯ 1

Дайте відповіді на запитання:

1.What is the purpose of the water pump?

2.Where is the water pump usually mounted?

3.What does the water pump consist of?

4.What is the impeller?

5.What is the impeller shaft supported on?

6.What prevents water from leaking out around the bearing?

7.What is the pump driven by?

8.What is the purpose of the engine fan?

9.Where is it usually mounted?

10.What types of belts are mostly used?

11.What is the advantage of the vee-type belt?

ЗАВДАННЯ 2

Перекладіть на англійську мову:

1.Водяний насос складається з корпуса з впускним та випускним вікном та крильчаткою.

2.Призначення вентилятора – забезпечити потужну тягу повітря через радіатор для кращого охолодження двигуна.

UNIT 7

ELECTRICAL SYSTEM

Слова та вирази для запам`ятовування:

TEXT A

PART I

PLUGS AND SPARKS

Every petrol-engine car needs electricity to provide current for the lights and other electrical equipment, and to supply the necessary power for the ignition system.

The ignition system enables the engine to be started and kept running, and sparking plugs form an essential part of this system.

Practically all plugs are of the same general construction. There are two main parts - a steel body, which screws into1 the cylinder and an insulated centre piece carring a rod or electrode. This is arranged in such manner2, that there is a small air gap3 between it and the earthed body, and it is across this gap that spark jumps.

Various metal alloys are used for the central electrode, which is an important part of a plug. Usually nickel is used despite its high cost.

Some plugs have three earthed electrodes or "points4", while others have only one; again there are plugs in which an earthed ring is formed around the central electrode so that the spark jumps the annular gap5.

The two usual plug sizes are known to be 14 mm and 18 mm, this being the metric diameter of threat.

They are screwed into the engine at, or near the top, usually one sparking plug for each cylinder. A four-cylinder engine, therefore, has four sparking plugs, the six-cylinder engine - six plugs and so on.

As the name suggests the purpose of the sparking plug is to make a spark and this spark is achieved by making the electric current jump a gap between two points (known as electrodes) which are at the extreme end6 of the plug which is inserted in the cylinder.

The spark ignites the fuel-air mixture in each cylinder, and very rapid burning and expansion results. This process is called "combustion" and it takes place in the "combustion chamber". It will be explained later just how this combustion fits into the operation of the engine.

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Electricity for the igniting process (ignition) is supplied by a dynamo and battery. The current is then carried to a coil, then to a distributor and finally to the sparking plugs.

ЗАВДАННЯ 1

Дайте відповіді на запитання:

1)Why does a petrol-engine car need electricity?

2)What is the purpose of a sparking plug?

3)What process is called "combustion"?

4)What are the main parts of the ignition system?

ЗАВДАННЯ 2

Перекладіть на англійську мову:

Система запалювання, свіча запалювання, паливно-повітряна суміш, камера згорання, процес запалювання.

ЗАВДАННЯ 3

Перекладіть на українську мову:

1)electric, electrical, essential;

2)ignition, expansion, combustion.

3)current, light, electrical equipment, power, ignition system, sparking plug, a spark, to ignite, fuel-air mixture, burning, expansion, combustion, combustion chamber, distributor.

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PART II

THE BATTERY AND THE COIL

The battery is used to store electricity. The electrical pressure (voltage) of a car battery is only 12 volts. When high-voltage electricity jumps a space between two points it causes a spark. This happens in a

sparking plug. A voltage of about 7000 volts from a 12 volt battery? The coil does it. The coil is really two coils of wire: the primary coil causes a very strong flow in the secondary coil. The flow through the primary coil is stopped by the contact breaker1.

THE CONTACT BREAKER AND THE DISTRIBUTOR

The contact breaker breaks or stops the flow of electricity in the primary coil. The distributor distributes the high-voltage electricity to the

sparking plugs. The electricity from the primary coil flows through the center of the distributor. This rod is turned by the camshaft. There are points in the contact breaker. The points can be opened so as to break the flow of electricity to the primary coil. A cam opens the points. They are closed by a spring. The cam of a four-cylinder engine fits on the rod from the camshaft.

It turns when the rod turns. Each corner of the cam presses on the contact breaker. This opens the points of the contact breaker. Now high-voltage electricity flows through the secondary coil to the distributor rotor arm.

The rotor arm is above the contact breaker cam. It is turned by the same rod from the camshaft. As the rotor arm goes round it touches points. Each of theses leads to a sparking plug. Each time the arm touches a point, the contact breaker points are also open. Then high-voltage electricity flows from the secondary coil to the rotor arm. From the rotor arm it goes to the sparking plug. This causes a spark.

Let us look at this again. The cam opens the points. The flow of electricity to the primary coil stops. High-voltage electricity flows in the secondary coil. It flows through the rotor arm to the sparking plugs. The cam turns. The points close. Electricity flows again into the primary coil. The rotor arm turns also. Contact with the sparking plugs is broken. All this is controlled from the camshaft.