Text 2.

Gasoline engine is an engine that uses gasoline as a fuel. Inside the engine, the combustion (burning) of fuel mixed with air produces hot gases that expand against parts of the engine and cause them to move. For this reason, gasoline engines are called internal-combustion engines. The motion inside the engine is transferred outside it to turn wheels and propellers or to operate machines. In this way, a gasoline turns heat energy into mechanical work. The rate at which a gasoline engine produces work is usually measured in horsepower or watts.

Gasoline engines are compact and light in weight for the power they produce. This makes them one of the most important types of engines for vehicles. Nearly all automobiles, lawn movers, motorcycles, motor scooters, snowmobiles, and small tractors have gasoline engines. So do many trucks, buses, airplanes, and small boats. Gasoline engines may also be used as portable power plants. For example, to supply power to run pumps and other machinery on farms.

Exercise 11. Memorize the following words and word combinations to text 3.

Piston - поршень

move up and down – рухатися вгору та вниз

back and forth – назад-вперед

crankshaft – колінчатий вал

reciprocating motion – зворотно-поступальний рух

rotary motion – обертальний рух

piston stroke – хід поршня

valve - клапан

arrangement – розташування

two- /four-stroke cycle – дво-/ чотиритактний цикл

fuel-air mixture – паливно-повітряна суміш

intake - впуск

compression - стискання

power stroke – робочий хід

exhaust - вихлоп

lawn mower - газонокосилка

compression ratio – ступінь стискання

high-octane gasoline – високооктановий бензин

lead - свинець

additive - присадка

pollutant – речовина, що забруднює

automobile exhausts – вихлопи автомобілів

catalytic converter – каталітичний конвертор

Exercise 12. Read and translate text 3.

Text 3. Kinds of gasoline engines

There are two main types of gasoline engines, reciprocating engines and rotary engines. Reciprocating engines have pistons that move up and down or back and forth. A part called a crankshaft changes this reciprocat­ing motion into rotary motion. A rotary engine uses devices called rotors instead of pistons. The rotors produce rotary motion directly. We will discuss reciprocating engines, the more common type.

Reciprocating gasoline engines are classified in a number of ways. These include:

1) by the number of piston strokes per cycle;

2) by the type of compression;

3) by the way they are cooled;

4) by their valve arrangement;

5) by their cylinder arrangement;

6) by the way they are supplied with air and fuel.

Cycle. Most reciprocating gasoline engines operate on either a two-stroke or a four-stroke cycle. Cycle means the steps that must be repeated for each com­bustion of the fuel-air mixture in the cylinders. Stroke means the up-and-down or back-and-forth movements of the pistons. A four-stroke cycle engine has intake, compression, power, and exhaust strokes. A two-stroke cycle engine combines the exhaust and intake steps near the end of the power stroke. Although two-stroke cycle engines are less fuel-efficient than four-stroke cycle engines, they are simpler and cheaper to build. A two-stroke cycle engine is used where low cost is important, as in a power lawn mower. It delivers more power for a given weight and size than does a four-stroke cycle engine. Each cylinder in a two-stroke cycle engine produces a power stroke for every turn of the crankshaft. But in a four-stroke cycle engine, a cylinder produces a power stroke on every other turn.

High and low compression. As a piston moves from the bottom to the top of a cylinder, it compresses the air and gasoline mixture. A number, called the compression ratio, tells how much the mixture is compressed. A high-compression engine may have a compression ratio of 10 to 1. Such an engine compresses the mixture to a tenth of its original volume. A low-compression engine may have a ratio of 8 to 1.

High-compression engines burn gasoline more effi­ciently than do low-compression engines. But high-com­pression engines require high-octane gasoline. Until the 1970's, the octane level of gasoline depended on the amount of lead additives - the more lead, the higher the octane. In the mid-1970s, man­ufacturers began to equip automobiles with devices called catalytic converters that reduce the pollutants in automobile exhausts. Lead was found to interfere with the effectiveness of catalytic converters. Automobiles with catalytic converters had to use low-octane gasoline because high-octane lead-free gasoline was costly to use.

Exercise 13. Find words in text 3 with the following meanings. (They are in the same order as in the text)

1. A long piece of metal in a vehicle that is connected to the engine and helps to turn the wheels.

2. A part of a machine that turns around on a central point.

3. A liquid obtained from petroleum, used mainly for producing power in the engines of cars, trucks etc, the same as petrol.

4. A part of a tube or pipe that opens and shuts like a door to control the flow of liquid, gas, air etc. passing through it.

5. A period of time needed for a machine to finish a process.

6. An object or container with circular ends and long straight sides.

7. A tube, pipe, etc. through which air, gas, or liquid enters a machine.

8. A type of hydrocarbon that is in fuel, and used as a measure of its quality.

Exercise 14. Match the words and word combinations in A with their equivalents in B

A	B
Combustion	a) рух ротора
fuel	b) паливно-повітряна суміш
motion	c) випуск / вихлоп (газів)
heat energy	d) ступінь стискання
vehicle	e) розташування клапанів
lawn mover	f) хід поршня
truck	g) присадка
pump	h) рівень октану
piston	i) забруднювач
up and down	j) назад-вперед
back and forth	k) впуск
crank shaft	l) згоряння / горіння
rotary motion	m) колінчатий вал
piston stroke	n) вверх-вниз
valve arrangement	o) рух
intake	p) вантажівка
fuel-air mixture	q) газонокосилка
compression / pressure ratio	r) теплова енергія
octane level	s) насос
additive	t) паливо
pollutant	u) транспортний засіб
exhaust	v) поршень

Exercise 15. Write questions to ask about the missing information and answer them.

Model: There are ____ main types of gasoline engines. How many main types of gasoline engines are there?

1. A part called crankshaft changes the reciprocating motion into _____.

2. ____ engines are classified in a number of ways.

3. Most reciprocating gasoline engines operate on either a __ or __ cycle.

4. Cycle means ______.

5. Stroke means the _____ movements of the pistons.

6. A ___ engine has intake, compression, power, and exhaust strokes.

7. A two-stroke cycle engine is used where ___ .

8. Each cylinder in a two-stroke cycle engine produces ___.

9. In a ____ engine, a cylinder produces a power stroke on every other turn.

10. A number, called the compression ratio, tells ____.

Exercise 16. Insert correct prepositions or adverbs.

1. A gasoline engine turns heat energy ___ mechanical work.

2. The rate ___ which a gasoline engine produces work is measured ___ horse power or watts.

3. Gasoline engines are compact and light ____ weight.

4. There are two main types ____ gasoline engines.

5. A crank shaft changes reciprocating motion ____ rotary motion

6. Reciprocating gasoline engines are classified ____ a number ___ ways.

7. Reciprocating gasoline engines are classified __ the way they are supplied ___ air and fuel.

8. A two-stroke cycle engine delivers more power ___ a given weight and size.

9. A high compression engine may have a compression ratio ___ 10 to 1.

10. The octane level ___ gasoline depended ___ the amount ___ lead additives.

Exercise 17. Having answered the following questions you will get ready to speak on the topic “Gasoline Engine”

1. What does gasoline engine use as a fuel?

2. Why are gasoline engines called internal combustion engines?

3. What makes gasoline engines very convenient for vehicles?

4. What types of gasoline engines are there?

5. What are reciprocating gasoline engines classified by?

6. What is the difference between “cycle” and “stroke”?

7. When are two-stroke cycle engines used and why?

8. What is the compression ratio?

9. What devices are called catalytic converters and what is their function?

Exercise 18. Translate into English.

1. Двигуни внутрішнього згоряння використовують бензин як паливо.

2. Бензинові двигуни перетворюють теплову енергію в механічну.

3. Бензинові двигуни використовуються як пересувні енергетичні установки для забезпечення енергією сільськогосподарської техніки.

4. Більшість поршневих двигунів працюють за дво- або чотиритактним циклом.

5. Питома витрата пального у двотактному двигуні вища, ніж у чотиритактному двигуні.

6. Ступінь стискання може дорівнювати 10 до 1.

7. Двигуни з високим ступенем стискання потребують високооктанового бензину.

Exercise 19. Translate text 4 in writing and choose one of the sentences given after it as the most suitable to finish the text.