Make 5 questions closely to the text
Практическая работа № 9.
What the first engine was like?
1. Match the phrases with the Russian equivalents:
2. Translate international words:ordinary, economical, boiler, machine, airoplane, locomotive, kerosene, diesel, gas, temperature, metal
3. Read and translate the text:
The first engine was called the “water wheel”. This was an ordinary wheel with blades fixed to it, and the current of the river turned it. These first engines were used for irrigating fields. Then a wind-power engine was invented. This was a wheel, but a very small one. Long wide wooden blades were attached to it. The new engine was driven by the wind. Some of these one can still see in the country. The water- and wind-operated engines are very economical, but they are dependent on the weather. Many years passed and people invented a new engine, one operated by steam. In a steam engine, there is a furnace and a boiler. The furnace is filled with wood or coal and then lit. The fire heats the water in the boiler and when it boils, it turns into steam which does some useful work. The more coal is put in the furnace, the stronger the fire is burning. The more steam there is the faster a train or a boat is moving. The steam engine drove all sorts of machines: steam ships and steam locomotives. The first airplane built by A.F. Mozhaisky had a steam engine. The steam engine had its disadvantages. It was too large and heavy, and need too much fuel.
The imperfections of the steam engine led to the design of a new type. It was called the internal combustion engine, because its fuel ignites and burns inside the engine itself and not in a furnace. It is smaller and lighter than a steam engine because it does not have a boiler. It is also more powerful, as it uses better-quality fuel: petrol and kerosene. The internal combustion engine is now used in cars, diesel locomotives and motor ships.
To enable airplanes to fly faster than the speed of sound another, more powerful engine was needed. One was invented and it was given the name “jet engine”. The gases in it reach the temperature of over the thousand degrees. It is made of a very resistant metal so that it will not melt.
4. Answer the questions:
1) What the first engine was like?
2) When can you see some of the wind-power engines?
3) What disadvantages have the water- and wind-operated engines?
4) How does a steam engine work?
5) What vehicles did drive a steam engine?
6) What advantages has an internal combustion engine?
7) Where is now used the internal combustion engine?
8) What is made the jet engine of?
Практическая работа № 10.
1. Match the phrases with the Russian equivalents:
2. Read and translate the text:
Most smaller motorbikes use two-stroke engines. These are lighter and smaller than four-stroke engines, and therefore cheaper. The efficiency of such engines is less than that of four-stroke engines, and therefore the power of a two-stroke engine is always less than half that of a four-stroke engine of comparable size.
The general principle of the two-stroke engine is to shorten the periods in which fuel is introduced to the combustion chamber. The suction and exhaust strokes can be eliminated if, at the end of the power stroke, the two valves are opened simultaneously and the fresh charge is forcibly blown in through the inlet valve driving out the waste gases through the exhaust valve. Then the two valves are closed again and the charge is ready for compression. A simpler way of doing the same thing is to provide openings in the cylinder wall at the lower end in such a way that they are uncovered by the piston as it nears the end of the power stroke. Valves are then no longer necessary. Since the cycle can now be completed in two strokes, it is called two-stroke or two-cycle. A two-cycle has a working stroke at every crankshaft revolution, and, therefore, gives nearly twice the power of a four-cycle engine, which has a working stroke only at every other crankshaft revolution.
The process of blowing out the spent gases by the incoming fresh charge is called scavenging, and the fan or blower or pump required to force the charge in is called the scavenger.
3. Find equivalents in English in the text:
1) Они легче и меньше, чем четырёхтактные двигатели, и поэтому дешевле
2) Основной принцип двухтактного двигателя - это сокращение периода в который топливо поступает в камеру сгорания.
3) Более простой путь сделать то же самое - это сделать отверстия в стенке нижнего края цилиндра таким образом, чтобы они открывались поршнем, как только он приближался к концу рабочего хода.
4) Большинство маленьких мотоциклов используют двухтактные двигатели.
5) Процесс выдувания остаточных газов при поступлении свежей порции топлива называется продувкой, а вентилятор, воздуходувка или насос, необходимый для нагнетания топлива называется продувочным устройством.
________________________4. Answer the questions:
1. What kind of land vehicles do two-stroke engines use?
2. Why are they cheaper than four-stroke engines?
3. Why the power of a two-stroke engine is always less than half that of a four-stroke engine of comparable size?
4. A two-cycle has a working stroke at every crankshaft revolution or at every other crankshaft revolution?
5. What process is called scavenging?
6. What is called the scavenger?
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