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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 |
| 1) Combustion | a) рух ротора |
| 2) fuel | b) паливно-повітряна суміш |
| 3) motion | c) випуск / вихлоп (газів) |
| 4) heat energy | d) ступінь стискання |
| 5) vehicle | e) розташування клапанів |
| 6) lawn mover | f) хід поршня |
| 7) truck | g) присадка |
| 8) pump | h) рівень октану |
| 9) piston | i) забруднювач |
| 10) up and down | j) назад-вперед |
| 11) back and forth | k) впуск |
| 12) crank shaft | l) згоряння / горіння |
| 13) rotary motion | m) колінчатий вал |
| 14) piston stroke | n) вверх-вниз |
| 15) valve arrangement | o) рух |
| 16) intake | p) вантажівка |
| 17) fuel-air mixture | q) газонокосилка |
| 18) compression / pressure ratio | r) теплова енергія |
| 19) octane level | s) насос |
| 20) additive | t) паливо |
| 21) pollutant | u) транспортний засіб |
| 22) 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.
Text 4. Gasoline
Gasoline is one of the most important fuels used for transportation. Most gasoline is used in engines that move automobiles and trucks. Gasoline engines also power such vehicles and machines as airplanes, motorboats, tractors, and lawn movers. People in the United Kingdom and some other countries call gasoline petrol because it is made from petroleum.
The widespread use of gasoline began in the early 1900’s, when the mass production of cars started. Gasoline-powered cars made travel easier. People no longer had to live near their jobs, and they could reach remote vacation spots more easily. Gasoline-powered farm machinery allowed for improved crop production.
Through the years, the increasing use of gasoline gave rise to a gigantic industry employing millions of people. However, the use of gasoline has also caused serious problems. For example, transporting petroleum and the manufacture and use of gasoline contribute heavily to air and water pollution.
1. Most gasoline is made by separating and chemically changing the different compounds in petroleum.
2. One of the most promising sources of gasoline for the future involves processing the oil contained in shale rock.
3. To solve the problems, gasoline manufactures are developing gasolines that pollute the environment less.
Exercise 20. Memorize the following words and word combinations to text 5.
Heavy-duty – 1) інтенсивний; потужний; надпотужний; 2) з важким режимом роботи
freight truck - вантажівка
road-building equipment– шляхобудівне знаряддя
submarine – підводний човен
emergency – аварія, аварійна ситуація; непередбачуваний випадок
ignite - запалювати
spark-ignition engine – двигун з іскровим запалюванням
spark plug – запальна свічка
compression-ignition – запалювання завдяки компресії
rod – шток, стрижень
inject- упорскувати
spray - розпилювати
supercharge - наддувати, нагнітати
throttle - дросель
thereby – таким чином
Exercise 21. Read, translate and give the gist of text 5.