Строение и работа двигателя (43415)

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Федеральное агентство по образованию РФ

Волжский политехнический институт (филиал)

Волгоградского государственного технического университета





Кафедра иностранных языков


Семестровая работа

по английскому языку

The Engine

(Перевод технического текста)

(7000 символов)


Выполнил:

Студент гр. ВТС-231

Мусаелян Э.А.


Проверил:

Преподаватель

Мозговая О.В.







Волжский 2008


Содержание


Введение

Технический текст на английском языке

Перевод текста

Краткий словарь (Vocabulary)

Заключение

Список литературы



Введение


Я выбрал тему двигатели потому что, я считаю, что сейчас в современном мире произошёл гигантский скачек вперёд, и даже не смотря на кризис в мировой промышленности, автопром нашей страны продолжает своё развитие, продолжает развивать и увеличивать свой ассортимент, повышая свою конкурентную способность, но в моей работе речь пойдёт не об этом.

А пойдет она о сердце любого автомобиля, о его можно сказать душе и с этим согласится любой знаток четырёх колёсного друга, речь пойдёт о двигателе. Моей целью было рассказать о двигателе что-то еще, так чтобы показалось интересно не только мне, но и окружающим. Я использовал разнообразную литературу, но в список включил только самое главное и основное откуда я почерпнул максимум информации. Искал я в самых разных источниках и изданиях, но чаше всего это были печатные издания.



The Engine. The engine is the source of power that makes the wheels go around and the car move. It is usually referred to as an internal-combustion engine because gasoline is burned within its cylinders or combustion chambers. This burning, or combustion, takes place at such high speed as to be termed an "explosion"; the high pressure thus created causes a shaft to turn or rotate. This rotary motion is transmitted to the car wheels by the power train.

Most automobile engines have six or eight cylinders, although some four-, twelve-, and sixteen-cylinder engines are in use.

Engine Operation. The activities that take place in the engine cylinder can be divided into four stages, or strokes. "Stroke" refers to the piston movement. The upper limit of piston movement is called top dead center, or T. D. C. The lower limit of piston movement is called bottom dead centre or B. D. C. A stroke constitutes piston movement from TDC to BDC or from BDC to TDC. In other words, the piston completes a stroke each time it changes direction of motion. Where the entire cycle of events in the cylinder requires four strokes (two crankshaft revolutions), the engine is called a four-stroke-cycle engine. The four strokes are: intake, compression, power and exhaust.

Intake. On the intake stroke the intake valve is opened. The piston is moving down, and a mixture of air and vaporized gasoline is being drawn into the cylinder through the valve opening. The mixture of gasoline and air is delivered to the cylinder by the fuel system.

Compression. After the piston reaches BDC it begins to move upward and at this instant the intake valve closes. The other valve is also closed so that the cylinder is sealed. The piston moves upward, compressing the mixture to as little as one sixth of its original volume or less. This creates a fairly high pressure within the cylinder.

Power. As the piston reaches TDC or the upper limit of its travel, an electric spark is generated at the cylinder spark plug. The spark plug consists of two electrodes, which are electrically insulated from each other. At the proper instant the ignition system delivers a high-voltage surge of electricity to the spark plug. This causes an electric spark to jump across the gap between the spark plug electrodes. The spark ignites or sets fire to the highly explosive mixture of gasoline vapor and air. Rapid combustion takes place, and the already high pressure within the cylinder increases to as much as 400 pounds per square inch. This terrific pressure against the top of the piston forces it downward, and a power impulse is transmitted to the engine crankshaft through the connecting rod and crank.

Exhaust. As the piston reaches the lower limit of its travel again, the exhaust valve opens. The piston moves upward on the exhaust stroke, forcing the burned gases out of the cylinder through the exhaust-valve opening. At the instant that the piston once more reaches top dead center, the exhaust valve closes and the intake valve opens so that, when the piston begins to move downward on the intake stroke, a fresh charge of gasoline vapor and air can be drawn into the cylinder. The above four strokes are continually repeated during the operation on the engine.

Fuel System. The fuel system is designed to store liquid gasoline and to deliver it to the engine cylinders on the intake strokes in the form of vapor mixed with air. The fuel system must vary the proportions of air and gasoline vapor to meet the requirements of the various operating conditions. Thus for initial starting with a cold engine a very rich mixture of about 9 pounds of air to 1 pound of gasoline is needed. After the engine has warmed up, it will run satisfactorily on a leaner mixture of about 15 pounds of air for each pound of gasoline. For acceleration and full-load, the mixture must again be enriched.

Thus for initial starting with a cold engine a very rich mixture of about 9 pounds of air to 1 pound of gasoline is needed. After the engine has warmed up, it will run satisfactorily on a leaner mixture of about 15 pounds of air for each pound of gasoline. For acceleration and full-load, the mixture must again be enriched.

The fuel system consists of a tank in which the liquid gasoline is stored, a fuel line, or tube, through which the gasoline can be brought from the tank to the engine, a pump, which pulls the gasoline through the fuel line, and a carburetor, which mixes the gasoline with air.

Fuel Pump. The fuel pump consists of a rocker arm, a flexible diaphragm, and two valves. The rocker arm rests against a cam on the camshaft so that rotation of the shaft makes the arm rock. This rocking motion causes the diaphragm to fluctuate up and down, alternately creating pressure and vacuum in the pump chamber. When vacuum is created, the inlet valve is lifted off its seat, allowing gasoline to be drawn from the fuel tank, through the fuel line, and into the pump chamber. On the return stroke the diaphragm creates pressure in the pump chamber. This causes the inlet valve to close and the outlet valve to open, forcing gasoline from the pump chamber through a fuel line to the carburetor.

Fuel Tank. The fuel tank, normally located at the rear of the vehicle and attached to the frame, is merely a storage tank made of sheet metal. It often contains a number of metal plates, which are attached to the inner surface of the tank parallel to the ends. These have openings through which the gasoline can pass, and their main purpose is to prevent sudden surging of the gasoline from one to the other end of the tank, when the car rounds a corner.

Power Train. The power that the engine develops must be transmitted to the car wheels, so that the wheels will rotate and cause the car to move. The power train performs this job, providing in the process several different gear ratios between the engine crankshaft and wheels, so that the engine crankshaft may rotate approximately four, eight, or twelve times to cause the wheels to rotate once. The power train consists of a series of gears and shafts, which mechanically connect the engine shaft with the car wheels, and contains a clutch, a transmission or change gears, a propeller shaft, and the final drive.

Clutch. The clutch permits the driver to connect the crankshaft to or disconnect it from the power train. A clutch is necessary since the automobile engine must be started without load. In order for the engine to deliver power, the crankshaft must be rotating at a reasonable speed of several hundred revolutions per minute or more. The engine will start at speeds below 100 r.p.m. (revolutions per minute), but it would not continue to operate at this low speed if a load were immediately thrown on it. Consequently, a clutch is placed in the power train between the crankshaft and transmission. The clutch permits the engine to run freely without delivering power to the power train. It also permits operation of the transmission so that the various gear ratios between the engine crankshaft and wheels may be obtained.



Двигатель. Двигатель - источник мощности, который заставляет колеса вращаться и автомобиль двигаться. Он обычно упоминается как двигатель внутреннего сгорания, потому, что бензин сжигается внутри цилиндров или камер сгорания. Это горение или воспламенение происходит с такой высокой скоростью, что может быть названо "взрывом"; высокое давление созданное таким образом вызывает поворот или вращение вала. Это вращательное движение передается на колеса автомобиля силовой передачей.

Большинство автомобильных двигателей имеют шесть или восемь цилиндров, хотя некоторые четырех-, двенадцати- и шестнадцати цилиндровые двигатели также эксплуатируются.

Работа двигателя. Действия, которые имеют место в цилиндре двигателя, могут быть разделены на четыре стадии или такта. "Такт" относится к движению поршня. Верхний предел движения поршня называется верхней мертвой точкой или ВМТ. Нижний предел движения поршня называется нижней мертвой точкой основания или НМТ. Такт включает движение поршня от ВМТ до НМТ, или от НМТ до ВМТ. Другими словами, поршень, завершая такт, каждый раз изменяет направление движения. Поскольку полный цикл событий в цилиндре требует четырех тактов (два оборота коленчатого вала), двигатель называется четырехтактным двигателем. Четыре такта: впуск, сжатие, рабочий ход и выхлоп.


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