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Text 5. Diesel Engine
Diesel engine is a type of internal-combustion engine used chiefly for heavy-duty work. Most of the locomotives in the United States are diesel powered. Diesel engines drive huge freight trucks, large buses, tractors, and heavy roadbuilding equipment. They are also used to power submarines and ships, the generators of electric-power stations in small cities, and emergency electric-power generators. Some automobiles are powered by diesel engines.
There are two main types of internal-combustion engines: gasoline engines and diesel engines. The gasoline engine, found in most cars, is a spark-ignition engine. It uses electricity and spark plugs to ignite the fuel and air mixture in the engine cylinders. The diesel engine is a compression-ignition engine. It compresses the air in the cylinders, causing the temperature of the air to rise. Fuel injected into the hot, compressed air immediately ignites.
During the combustion process, the stored chemical energy in the fuel is converted to thermal, or heat, energy. The temperature in each cylinder rises as high as 2,480ºC and creates pressures of 1,500 pounds per square inch. The pressure pushes against the tops of the pistons, forcing them to the other end of their cylinders. The pistons are connected by a rod or other mechanism to a crankshaft that they turn. In this way, a diesel engine supplies rotary power to drive vehicles and other machines.
To ignite the fuel, the compressed air must have a certain temperature. The degree to which the temperature of the air rises depends on the amount of work done by the piston in compressing it. This work is measured as a ratio between the volume of uncompressed air and the volume of the air after compression. The compression ratio necessary to ignite the fuel depends on the size of the engine cylinders. In large cylinders, the compression ratio is about 13 to 1. For small cylinders, it may be as high as 22 to 1.
Near the end of the piston compression stroke, the fuel is injected into the cylinder. In order for the fuel and air to mix well, the fuel is injected under high pressure as a spray. Combustion usually starts just before the piston ends its compression stroke. The power of diesel engines can be increased by supercharging, or forcing air under pressure into the cylinder.
Diesel engines have a high thermal efficiency, or ability to convert the stored chemical energy in the fuel into mechanical energy, or work. In the spark-ignition engine, the amount of power produced is determined by a throttle that regulates how much air and fuel enter the cylinder. The throttle may operate in a partly closed position much of the time, thereby reducing the engine air intake and efficiency. Diesel engines do not require a throttle, making them more efficient than gasoline engines.
A cycle begins with the intake stroke when the piston moves down and draws air into the cylinder. The piston rises and compresses the air. During the compression stroke, the air temperature rises to about 480ºC. When fuel is injected into the cylinder, it mixes with the hot air and burns explosively. Gases produced by this combustion push the piston down for the power stroke. During the exhaust stroke, the piston moves up and forces the burned gases out of the cylinder.
Exercise 22. Match the words in A with their synonyms in B
| A | B |
| 1) spray | a) at once |
| 2) heavy | b) provide |
| 3) duty | c) boat |
| 4) truck | d) obligation |
| 5) ship | e) atomize |
| 6) internal | f) decrease |
| 7) ignite | g) turn into |
| 8) compression | h) amount |
| 9) immediately | i) pressure |
| 10) convert | j) fire |
| 11) supply | k) inner |
| 12) rise | l) lorry |
| 13) volume | m) weighty |
| 14) start | n) increase |
| 15) reduce | o) commence |
Exercise 23. Complete the following sentences with the words from text 5.
1.Most of the locomotives in the United States are ____.
2.There are two main types of internal-combustion engines: ____.
3.The diesel engine is a ___ engine.
4.The diesel engine compresses the air in the cylinders, causing _.
5.During the combustion process, ___ in the fuel is converted to thermal, or heat, energy.
6.The pressure pushes against the tops of the pistons, forcing them ____.
7.To ignite fuel ___ must have a certain temperature.
8.The work done by the piston is measured as a ratio between __ an the volume of the air after compression.
9.___ usually starts just before the piston ends its compression stroke.
10. The amount of power produced is determined by throttle that regulates ___ enter the cylinder.
Exercise 24. Say what is true and what is false. Correct the false sentences using the expressions of agreement or disagreement given below.
I don’t agree with the statement.
I disagree with this.
I am afraid I can’t agree with you here.
I am afraid (I think) you are mistaken.
I see your point, but … .
On the contrary.
Nothing of the kind, I am afraid.
I am sure, that ...
1. Diesel engines drive huge freight trucks, large buses, tractors, and heavy road-building equipment.
2. The gasoline engine found in most railway trains is a spark-ignition engine.
3. The diesel engine compresses water in tanks, causing the temperature of the air to rise.
4. During the combustion process, the electrical power is converted to thermal or heat energy.
5. The pistons are connected by a rod to a crank-shaft that they turn.
6. As soon as the piston compression stroke starts, the fuel is injected into the cylinder.
7. Combustion usually stops just before the piston ends its compression stroke.
8. The throttle may operate in a partly closed position, thereby increasing the engine air intake.
Exercise 25. Answer the following questions on text 5.
1. What work are diesel engines chiefly used for?
2. What means of transport use diesel engines?
3. Where else can these engines be used?
4. What are two main types of internal-combustion engines?
5. What causes the temperature rise in the engine?
6. What is converted into the thermal or heat energy in the internal combustion engine?
7. Why is it necessary to ignite the fuel?
8. What does the pressure ratio come to in large and small cylinders?
9. What determines the spark-ignition engine?
10. How does a four-cycle diesel engine work?
Exercise 26. Translate into English.
1.Дизельні двигуни використовуються майже в усіх транспортних засобах.
2.Більшість сучасних авто використовують бензинові двигуни з іскровим запаленням.
3.Накопичена в паливі хімічна енергія перетворюється в процесі згоряння в теплову енергію.
4.Ступінь стискання, необхідний для запалення пального, залежить від розміру циліндрів двигуна.
5.В невеликих за розміром циліндрах ступінь стискання може дорівнювати 22 до 1.
6.Процес горіння зазвичай починається перед тим, як поршень закінчує стадію компресії.
7.Дизельні двигуни не потребують дроселя, що робить їх ефективнішими за бензинові.
8.Дизельні двигуни більше підходять для виконання важких робіт, ніж бензинові двигуни однакової потужності, оскільки вони можуть витримувати великі навантаження.
9.Дизельне пальне потребує менше очищення і є дешевшим, ніж паливо вищої якості, таке, як бензин.
Exercise 27. Make up a dialogue on diesel engines.
Exercise 28. Read text 6 filling the spaces with the words given below in brackets.
(provides, compresses, a cycle, upstroke, draws, stroke, differ, exhausts, downstroke, valves, piston, intake, occur, ports, injected)
Text 6. Kinds of Diesel engines
There are two main types of diesel engines. They …according to the number of piston strokes required to complete … of air compression, power, exhaust, and … of fresh air. A … is an up or down movement of a piston. These engines are the four-stroke cycle engine and the two-stroke cycle engine.
In a four-stroke cycle engine, each … moves down, up, down and up to complete a cycle. The first downstroke … air into the cylinder. The first upstroke … the air. The second downstroke is the power stroke. The second upstroke … the gases produced by combustion. A four-stroke engine requires exhaust and air-intake valves.
In a two-stroke cycle engine, the intake and exhaust processes … near the end of the piston … or power stroke. The two-stroke cycle engine does not need … . As the piston rises during the …, it compresses the air and closes the intake and exhaust … .The fuel is … near the end of this compression stroke. Because the two-stroke cycle engine has twice as many power strokes as the four-stroke cycle engine, it … more power.
Exercise 29. Translate text 6 in the written form and make a summary of it in English.
Exercise 30. Translate the following text in writing, then try to make a back translation into English and compare it with the original.
History. The diesel is named for Rudolf Diesel, the German engineer who invented it. Diesel patented his design for the engine in 1892 and built his first engine in 1893. The engine exploded and almost killed him, but it proved that fuel could be ignited without a spark. He operated his first successful engine in 1897. Later, Sir Dugald Clerk of Great Britain developed the two-stroke diesel.
Exercise 31. Speak on:
1. Internal Combustion Engine.
2. Gasoline Engines.
3. Diesel Engines.
4. Gasoline and Diesel Fuels.
Exercise 32. Find Gerunds in the following sentences and translate them
1.Antioxidants keep the gasoline from becoming gummy.
2.Anti-icer prevents ice from clogging gas lines in winter.
3.Antirust agents prevent tanks and fuel lines from rusting.
4.Metal deactivators keep small amounts of metal impurities from changing the properties of gasoline.
5.In the early 1970’s U.S. petroleum refiners had difficulty in meeting gasoline demand.
6.Reducing chemicals containing sulfur lowers the octane number of gasoline.
7.High levels of oxygenates also help reduce the amount of carbon monoxide produced by burning gasoline, especially in older cars.
8.Most gasoline is made by separating and chemically changing the different compounds in petroleum.
9.Promising sources of gasoline for the future involves processing the oil contained in shale rock.
- To operate smoothly a high-compression engine needs a gasoline more resistant to knocking than does a low-compression engine.
- A gasoline’s ability to resist knocking is called its anti-knock quality.
- The piston has two to six rings to prevent the gases from escaping past the piston and to keep lubricating oil from getting into combustion chamber.
Exercise 33. Complete the sentences, using different forms of Gerund.
- They insisted on (clean) the tanks without delay.
- They insisted on the tanks (clean) without delay.
- Do you realize the importance of (follow) the manufacturer’s instructions?
- He insisted on (inform) passengers about the delay of flight as soon as possible.
- Passengers insisted on (inform) about the time of departure.
- Flight assistants always give information about the time of (land).
- The mechanic mentioned (notice) the leakage before landing.
- She is very fond of (look) through the window during flight.
- The storm prevented the ship from (reach) the airport on time.
- They were very disappointed at not (inform) beforehand.
- There was no chance of (find) the plane in the mountains.
- They were very proud of (find) a correct decision in such a dangerous situation.
Exercise 34. Finish the following sentences using Gerund.
- I am afraid of …
- We insist on…
- They are looking forward to …
- She was accused of …
- My friends are fond of ..
- Never object to ..
- Try to get used to …
- All people should always prevent from …
- We should be grateful for …
- Be proud of …