automobiles

UNIT 17. THE ELECTRICAL SYSTEM

TEXT 1. THE BATTERY AND 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 the sparking plug. A voltage of about 7,000 volts will cause a good spark. How do we get 7,000 volts from a 12-volts battery?

The coil does it. The coil is really two coils of wire: the primary coil and the secondary coil. The electricity (12 volts) from the battery flows through the primary coil. Suddenly stopping the flow the primary coil causes a very strong flow in the secondary coil. The flow through the primary coil is stopped by the contact breaker.

Exercise 1. Memorize the following words and word combinations:

Exercise 2. Translate into Ukrainian.

THE IGNITION SWITCH

The ignition switch is an electrical switch that turns the current off or on in the ignition circuit. It operates in the same manner as the light switches in your home. It is usually located on the instrument panel and is operated by a key, so that only the person who has the key can turn on the switch. The ignition switch, in addition to completing the ignition circuit, usually has additional terminals which complete the circuits to the instruments or warning lights (fuel, temperature, oil pressure, charging), to the accessories (heater, radio, etc.), and to the starting motor. The ignition, instrument, and accesso-

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ries circuits are completed when the switch is turned to the ignition position. The instrument and the accessories circuits are connected when the switch is turned to the accessories position. Only the starting circuit is connected when the ignition switch is in the start position.

TEXT 2. THE CONTACT BREAKER AND

THE DISTRIBUTOR

The contact breaker stops or breaks 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 centre 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. The points are opened by a cam. 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. (A condenser stops any spark at these points). Now high-voltage electricity flows through the secondary coil to the distributor rotor arm. The rotor arm is 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 these 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.

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Exercise 3. Memorize the following words and word combinations.

Exercise 4. Answer the following questions:

1.How do we get high-voltage electricity from a car battery?

2.What is the purpose of the contact breaker?

3.What causes a spark and how does it get to the sparking

plug?

4. How does the high-voltage electricity get to the proper sparking plug?

TEXT 3. THE FIRING SEQUENCE

A car usually has four or six cylinders. It may have more. If all the cylinders fired together, the movement of the crankshaft would not be smooth. So they fire quickly one after the other. The camshaft controls this firing, and the crankshaft has a special shape for it. The sequence of firing in a four-cylinder engine is 1-3-4-2.

Cylinder 1 has fired. The piston is moving down. This movement is passed to the crankshaft through the connecting rod.

Cylinder 3 is compressing the air-petrol mixture.

Cylinder 4 is drawing in the air-petrol mixture from the carbu-

rettor.

Cylinder 2 is pushing out the smoke and gases after the explo-

sion.

In this way a smooth movement is given to the crankshaft.

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Exercise 5. Speak on the sequence of firing in a four cylinder engine using the given words and word combinations:

cylinder, to fire, piston, to move down, to pass to the crankshaft, through the connecting rod, to compress the air-petrol mixture, to draw in the mixture, carburettor, to push out the smoke and gases, explosion.

TEXT 4. THE BATTERY AND DYNAMO

The battery only stores electricity. If we use too much, all the electricity will be gone. So something must put electricity back into the battery. This is done by the dynamo. The dynamo is a small machine that makes electricity. It is turned by the crankshaft through a belt. (This belt also turns the cooling fan).

The electricity from the dynamo flows into the battery. This keeps the battery full of electricity (charged). A small instrument (the voltage regulator) stops too much electricity from flowing into the battery (overcharging). So the dynamo recharges the battery when the engine is running.

Exercise 6. Answer the following question:

What is a dynamo?

TEXT 5. THE STARTER MOTOR

The pistons turn the crankshaft. If the crankshaft is turned, the pistons will move. The coil, rotor arm, contact breaker, camshaft, sparking plugs will begin to work. The engine will start. How do we turn the crankshaft? This is done by the starter motor. This is a powerful electric motor. When the starter switch is turned, electricity from the battery flows to the starter motor. (Some cars have an ignition switch and a starter switch).

Two things happen:

1. A rod in the starter motor moves forward. There is a small gear wheel on the front of this rod. This meshes with the teeth of a large wheel (the flywheel). The flywheel is fixed on the back end of the crankshaft.

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2. The starter motor turns. It turns the flywheel and the crankshaft. The engine starts. The gear of the starter motor moves back from the flywheel.

Exercise 7. Memorize the following words and word combinations:

Exercise 8. Answer the following questions:

1.What is the purpose of the starter motor?

2.Where does the starter motor get the electricity from?

3.What meshes with the teeth of the flywheel?

4.Where is the flywheel fixed?

Exercise 9. Complete these statements with the correct words:

1.The battery is used … electricity.

2.The electrical … of a car battery is 12 volts.

3.The electricity from the battery flows through the … coil.

4.The flow through the primary coil is stopped by the … .

5.The contact breaker … or … the flow of electricity in the primary … .

6.The rotor arm is the … … can.

7.The dynamo is a small machine that makes … .

8.The dynamo … the battery when the engine is running.

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UNIT 18. THE COOLING AND LUBRICATION SYSTEM

TEXT 1. THE COOLING SYSTEM

Engines become very hot while they are running, due to the intense heat created by combustion. Some form of cooling must therefore be adopted and in most cars water is used.

The water enters the cylinder block near the bottom of the cylinders, and flows through special passages cast in the cylinder block and cylinder head. As it absorbs the engine heat its temperature increases and this causes it to flow upward. When it reaches the top of the engine the water is very hot. Now the water itself must be cooled, otherwise it would boil. This is done by means of a radiator. The hot water leaves the top of the engine and filters through the radiator where it is cooled by the passage of air. As it cools it falls to the bottom of the radiator from where it re-enters the engine. A pump, driven by the fan belt, helps to force the water through the system and so improves its cooling efficiency.

Some engines are cooled by air only, not by water.

Exercise 1. Answer the following questions:

1.What is the purpose of the cooling system?

2.How does a water cooling system work?

3.Are there engines cooled only by air?

Exercise 2. Fill in the blanks with appropriate words:

1.Engines become very hot while they are running due to the

…created by … .

2.The water enters … near the bottom of the cylinders.

3.As water absorbs the engine heat its temperature … .

4.When water reaches … it is very hot.

5.Water is cooling by means of a … .

6.A pump, driven by … helps to force the water through the

system.

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Exercise 3. Translate into English.

Коли двигун працює, він нагрівається від спалахів у циліндрах. Як утримувати двигун холодним? Це виконується за допомогою води. Вода тече від радіатора. Вона витікає через отвори у блоці циліндрів. Коли вода нагрівається, вона піднімається до верхньої частини блоку. Звідси вона повертається до верхньої частини радіатора за допомогою невеликого насоса. Гаряча вода з двигуна повільно протікає через радіатор. Коли автомобіль рухається, повітря проходить через радіатор і охолоджує воду.

TEXT 2. THE LUBRICATION SYSTEM

Faithful and appropriate lubrication is an essential requirement for trouble-free operation and it increases the service life of motor vehicle. There are many places in an engine where metal rubs against metal. For example, the piston rings rub against the cylinder walls; the crankshaft rubs against the inside of the big end. When this happens, the metal gets hot. In an engine this extra heat must be avoided or the parts will wear out quickly and become damaged. Oil greatly reduces friction and allows the parts to run smoothly together.

An oil reservoir, or sump, is provided at the bottom of the engine. The sump holds over one gallon (4,5 litres) of oil. From the sump the oil is pumped under pressure through various pipes and passages to the moving parts where there is friction: the cylinder, the crankshaft, the camshaft, pistons and valve operating mechanism. The oil in the sump can be checked by a dipstick, and it must be maintained at the correct level by adding more when necessary. It is essential to watch permanently the oil-pressure gauge of the flashing of the pilot lamp when driving. Whenever the oil-pressure gauge fails to indicate, the engine has to be stopped immediately. Special care has to be taken that the oil supply line is tightly attached to the pressure gauge.

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Exercise 4. Memorize the following words and word combinations.

Exercise 5. Find synonyms:

Exercise 6. Answer the following questions:

1.What causes the engine to wear?

2.What is the purpose of lubricating system?

3.How does this system work?

4.How can the oil in the sump be checked?

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Exercise 7. Translate into English:

1.Важливою вимогою двигуна є змащування.

2.Перед виїздом автомобіля необхідно перевірити рівень

мастила.

3.Рівень мастила у теплому двигуні потрібно перевіряти за декілька хвилин після зупинки двигуна.

4.Перевірте рівень мастила в картері (crankshaft) двигу-

на.

5.Ми можемо зменшити небезпеку перегріву деталей за допомогою змащування.

6.Плівка мастила на поверхні метала захищає його від

корозії.

7.Після змащування проверніть вали декілька разів вру-

чну.

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UNIT 19. THE CLUTCH

Transmission system of a car is a series of assemblies whose purpose is to transmit the power of the engine to the road wheels. The first of these is the clutch assembly. This enables the remainder of the transmission system to be disconnected from the engine, when necessary, so that the various gears in the gearbox can be engaged.

At the back of the engine is a heavy flat wheel known as the flywheel. It is attached to the rear end of the crankshaft and revolves with it. A clutch plate, consisting of a metal disc with a friction lining round its outer edge, is held firmly against the flywheel by a springloaded pressure plate. As the flywheel revolves the clutch plate revolves, and it is simply the pressure of one against the other that provides the drive from engine to transmission.

The clutch is operated by the clutch pedal inside the car. When the driver depresses the pedal the clutch pressure plate is forced away from the flywheel, thus disconnecting the engine from the transmission. When the pedal is released, the pressure plate forces the clutch plate against the flywheel and the drive is taken up again.

Exercise 1. Memorize the following words and word combinations:

Exercise 2. Answer the following questions:

1.What system of a car transmits the power of the engine to the road wheels?

2.What device is used to engage or disengage the flow of power from an engine to a transmission?

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