Лабораторная работа № 1

Английский язык. Профессиональный перевод.

Бармина Наталья Александровна, к.т.н., доцент каф. «Английский язык»

barmina-nat@mail.ru, 89127663524 (Viber, WhatsApp)

План работы:

1. Участие в зум-занятии 28 сентября и 1 октября 2020 года
2. Изучение аннотирования и реферирования текста (на зум-занятии или самостоятельно) (файл abstract and summary.doc)
3. Выполнение 3 лабораторных работ (номер вариант сообщает преподаватель, если вы отсутствовали на контактных занятиях, напишите на адрес Barmina-nat@mail.ru с указанием ФИО и номера группы)
4. Оформленные по шаблонам три лабораторные работы необходимо выполнить и прислать до 30 декабря 2020 года (на почту barmina-nat@mail.ru)

Преподаватель проверяет работы до 10 января 2020 года и сообщает формат сдачи экзамена.

Лабораторная работа № 1.

Изучение и сравнительный анализ он-лайн словарей при переводе

Профессионально-ориентированного текста с английского на русский язык

 

Задание:

1. Открыть в интернете 3 он-лайн словаря (Multitran, Abby Lingvo, один найти самостоятельно).

2. Перевести с помощью трех словарей 20 подчеркнутых слов и словосочетаний из предложенного текста (номер варианта сообщает преподаватель, если вы отсутствовали на контактных занятиях, напишите на адрес Barmina-nat@mail.ru) с английского языка на русский. Обратить внимание на тематику текста, от нее зависит вид подсловаря (в частности, при использовании словаря Multitran). Если в тексте глагол встречается не в начальной форме, в отчете нужно написать его в начальной форме. Множественное число существительных необходимо в отчете заменить на единственное число.

3. Занести слова и их перевод в таблицу, проанализировать результаты.

4. Сделать сравнительный анализ словарей и вывод. В выводе нужно обратить внимание на достоинства и недостатки работы с вышеперечисленными он-лайн словарями, выявленные студентом при работе с ними; указать наиболее удобный в использовании он-лайн словарь и т.д.

5. Отчет в электронном виде выслать преподавателю в обозначенные сроки на адрес barmina-nat@mail.ru.

 

Варианты заданий к Лабораторной работе № 1 «Изучение и сравнительный анализ он-лайн словарей при переводе профессионально-ориентированного текста с английского на русский язык»

Вариант 1

To complete the cycle of operations, four strokes of the piston are used. This involves two complete revolutions of the crankshaft, the inlet and exhaust valves being mechanically opened and closed at the correct times.

Starting with the piston at TDC and the crankshaft rotating clockwise (looking from the front of the engine), the strokes operate as follows.

With the inlet valve open and the exhaust v alve closed the piston moves in a downwards direction drawing in a mixture of petrol vapour and air. This is called the induction stroke.

The piston moves up with both valves closed, thus compressing the mixture into the combustion chamber at the top of the cylinder. This is the compression stroke.

At the end of the compression stroke a spark occurs at the sparking plug. This ignites the mixture which burns very rapidly heating the gas to a very high temperature which also raises its pressure. This forces the piston down the cylinder and is called the power stroke.

As the piston begins to rise the exhaust valve opens and the spent gases are forced out of the cylinder. This is called the exhaust stroke. At the end of this stroke the exhaust valve closes and the inlet valve opens.

This cycle of induction, compression, power and exhaust opera t es on a continuous basis all the time the engine is running. As can be seen the complete cycle of operations of a four-stroke engine occupies two complete revolutions of the crankshaft. The SI engine draws into the cylinder a mixture of petrol and air which is compressed and burnt. The CI engine draws air only into the cylinder which is compressed to a very high pressure.

This also raises its temperature and when fuel is sprayed into the combustion chamber it self-ignites.

Two-stroke cycle of operations:

By using both sides of the piston the four phases (induction, compression, power, and exhaust) are completed in two strokes of the piston and one revolution of the crankshaft.

 

Вариант 2

There are three arrangements which may be used for an engine.

In-line engine: The cylinders are arranged in a single row, one behind the other. They may be vertical, as in most modern light vehicles, horizontal as used in coaches where the engine is positioned under the floor, or inclined at an angle to allow for a lower bonnet line.

Vee engine: The cylinders are arranged in two rows at an angle to one another. The angle for two-, four- and eight-cylinder engines is usually 90°. For six- and twelve-cylinder engines the angle is usually 60°.

 Opposed piston or cylinder engine: This is where the cylinders are at an angle of 180° apart and usually positioned horizontally.

Firing orders

When considering multi-cylinder engines and firing orders, the power strokes should be spaced at equal intervals to give the smoothest possible running of the engine. Each interval is equal to the number of degrees per cycle of operation. This will be 720° for a four-stroke engine. This is then divided by the number of cylinders, e.g. 720=4 x180 °.

Therefore the firing interval for a four cylinder in-line engine will be 180° and that for a six-cylinder in-line engine will be 720=6 x 120°. The firing order is determined by two things.

1. The position of the cylinders and the cranks on the crankshaft (this determines the possible firing orders).

2. The arrangement of the cams on the camshaft (this must be in accordance with one of the possible firing orders).

The arrangements on the crankshaft are such that the pistons on a four-cylinder in-line engine are moved in pairs, e.g. numbers 1 and 4 form one pair and 2 and 3 form the other pair. This means that when number 1 is moving down, on its power stroke, number 4 will also be moving down, but on its induction stroke. Depending on the firing order, when number 2 piston moves upwards it will either be on its exhaust or compression stroke, number 3 will be on its compression or exhaust stroke. From this then we can see that there are two possible firing orders for a four-cylinder in-line engine. These are 1342 or 1243, both of which are in common use today.

The reasons for using more than one cylinder are very complex but in simple terms they are as follows.

A multi-cylinder engine has a higher power­-to-weight ratio than a single-cylinder engine. With multi-cylinder engines there are more power strokes for the same number of engine revolutions. This gives fewer fluctuations in torque and a smoother power output.

A better acceleration is achieved due to smaller moving parts and more firing imp ` ulses.

Вариант 3

As the piston reaches TDC the fuel is ignited by the spark at the spark plug and the burning process of the mixture begins. As the gases rapidly expand the piston is forced down the cylinder on the power stroke. The speed of the flame front must not exceed the speed of the power stoke.

Combustion in a petrol engine originates (begins) at the spark plug and then progresses across the combustion chamber in a controlled manner. In the case of the diesel engine, combustion of the fuel is initiated (started) by the heat of the air in the chamber. As the droplets of fuel pass through the air they absorb the heat, and, if the temperature is high enough, the fuel will vaporize and ignite. Wide distribution of the fuel during the heating phase means that the burning process (combustion) starts at many different points in the chamber.

In direct injection systems, once ignition has started, most of the burning will tend to concentrate in zones fairly close to the injector. These zones must be fed with air in order to sweep away the burnt gases and supply the oxygen necessary for complete combustion. Any lack of oxygen in the combustion region will lead to black smoke in the exhaust.

A common and essential objective of all CI or diesel engine combustion systems is to achieve the maximum degree of mixing of the fuel, in the form of very fine droplets, with the air. This happens during injection of the fuel into the combustion chamber.

There are two main methods of introducing fuel into the combustion chamber: direct and indirect injection. In the ‘direct injection’ system the fuel is injected directly into the combustion chamber which is formed in the piston crown. The air is made to rotate in this cavity at 90° to the incoming swirl by the squeezing out of the air from between the cylinder head face and the piston crown as the piston approaches the end of its compression stroke. This rapid movement of the air is called turbulence.

 

Вариант 4

As we have seen, the function of the camshaft is to open the valves at the correct time in the cycle of operations of the engine. It is also used as a drive for various auxiliary units such as the distributor, fuel pump and oil pump.

The position of the camshaft can be in the cylinder block (often termed as side-mounted).

The main advantage of this arrangement is that the timing is not disturbed when the cylinder head is removed. An alternative position is on the top of the cylinder head (termed the over head cam or OHC). This has the advantage of there being a considerable reduction in components that are required to transmit the movement of the camshaft to open the valves.

The camshaft driving gear or sprocket is located on the shaft by means of a woodruff key or dowel peg to ensure correct fitting, and therefore correct timing, and to give a positive location of the driving gear.

Several methods are employed to transmit the drive from the crankshaft to the camshaft, these are chain, gear and toothed belt. The most common one in use on modern OHC engines is the toothed belt drive. This has the advantages of being silent in operation, requiring no lubrication and being fairly easy to remove and replace.

This is made from high tensile alloy steels, e.g. those containing nickel, chromium and molybdenum.

This is also made from high tensile alloy steels, for example, those containing alloys of cobalt chromium and silicon chromium, silicon chromium austenitic steel, all of which resist oxidation, corrosion and wear. Under full power it can reach temperatures of around 650 °C. For extreme operating conditions the valve stem is made hollow and partly filled with sodium, which is a very soft metal having a melting point of approximately 98° C. Under running conditions it is molten, and in splashing from end to end of the valve stem it assists the transfer of heat from the hot valve head to the valve stem.

 

Вариант 5

The main function of the piston is to provide the movable end of the cylinder, so as to convert the expansion of the burning gases on the power stroke into mechanical movement of the piston, connecting rod and crankshaft. On some types of engines the piston crown is designed to a specific shape instead of being flat. This allows for the shape of the combustion chamber to be included in the piston crown instead of in the cylinder head, and may also have an effect on the flow of gases into and out of the cylinder.

Several shapes are used in the manufacture of the lower part of the piston, called the piston skirt, e.g.

· Solid skirt used in both CI and SI high speed engines, where heavy loadings may be placed on the piston;

· Split skirt where small clearances are used to reduce piston slap when the engine is cold;

· Slipper type which is used to reduce the weight of the piston by cutting away the bottom of the non-thrust sides of the piston skirt; at the same time it reduces the area in contact with the cylinder wall, and also allows for a reduction in the overall height of the engine as BDC is now closer to the crankshaft.

When cold, the piston head is smaller in diameter than the skirt. When the engine is operating at its normal temperature the piston head expands more than the skirt due to its being closer to the very hot gases and also the fact that there is a greater volume of metal at this point.

The piston ring seals the gap left between the piston and the cylinder wall. Made from high-grade centrifugally cast iron, it is split to enable the ring to be assembled onto the piston. Some rings may be coated on their outer edge with chromium to give better wear characteristics and longer life. Normally three rings are fitted. The top compression ring takes most of the compression pressure and forms the first defence against the heat and escaping gases. It may be stepped so that it misses the ridge that tends to form in the cylinder bore at TDC. The second is also a compression ring that completes the sealing against compression loss.

 

Вариант 6

To understand how the oil does its work in the operation of the engine and other parts of the motor vehicle, we first need to understand what is meant by friction. The term friction is defined as a resistance to movement between any two surfaces in contact with each other.

In some cases friction on a vehicle is useful. The type of friction which keeps our feet from slipping when we are walking also provides the frictional grip that is required between the tyres and the surface of the road, the brake pads and the brake disc, the drive belt and the pulleys of the fan and crankshaft.

If friction occurs in the engine it can cause serious problems as it destroys the effectiveness of the engine components due to the heat generated.

This in turn causes wear and early failure of components such as bearings and their journals. It follows then that this type of friction must be reduced to a minimum to allow the engine to operate satisfactorily.

Many years ago it was found that considerable effort was required to drag or push a heavy stone along the ground. It was found to be much easier to roll the stone. It was later discovered that when the stone was put onto a raft and floated on water it was easier still to transport the same stone.

It was almost impossible to move the stone by sliding it along the ground because dry sliding friction creates a lot of resistance. This type of friction is used in the brakes and so is useful. When the stone was rolled it was found to be easier to move. Rolling friction creates a lot less resistance and therefore far less heat. This type of friction exists in the ball-and roller-type wheel bearing. When the stone was placed on a raft and floated on the water it made the work lighter still. This is called fluid friction and exists in the sliding bearings under certain conditions as it does in the crankshaft bearings.

Вариант 7

The most common types of pumps used in the motor vehicle engines are the gear, rotary or vane.

Gear pump consists of two gears in a compact housing with an inlet and outlet. The gears can be either spur or helical in shape (the helical being quieter in operation). The pump drive shaft is mounted in the housing and fixed to this is the driving gear. Oil is drawn via the inlet into the pump. It passes through the pump in the spaces between the gear teeth and pump casing and out through the outlet at a faster rate than is used by the system. In this way pressure is created in the system until the maximum pressure is reached at which time the pressure-relief valve will open and release the excess pressure into the sump.

The main parts of rotary type of pump are the inner rotor, the outer rotor and the housing containing the inlet and outlet ports. The inner rotor, which has four lobes, is fixed to the end of a shaft; the shaft is mounted off-centre in the outer rotor which has five recesses corresponding to the lobes. When the inner rotor turns, its lobes slide over the corresponding recesses in the outer rotor turning it in the pump housing. At the inlet side the recess is small; as the rotor turns the recess increases in size drawing oil up from the sump into the pump. When the recess is at its largest the inlet port finishes, further movement of the rotor reveals the outlet port and the recess begins to decrease in size forcing the oil under pressure through the outlet port.

Vane-type pump takes the form of a driven rotor that is eccentrically mounted (mounted offset) inside a circular housing. The rotor is slotted and the eccentric vanes are free to slide within the slots, a pair of thrust rings ensuring that the vanes maintain a close clearance with the housing.

 

Вариант 8

When the oil passes through the engine it becomes contaminated with carbon (the byproduct of the combustion process), dust (drawn in from the atmosphere), small metal particles (from components rubbing together), water and sludge (a combination of all these impurities mixed together). All these will cause engine wear if they remain in the oil, so the engine must be equipped with a filtering system that will remove them and keep the oil as clean as possible. Most modern engines are equipped with a filtering system where all the oil is filtered before it reaches the bearings. This arrangement is called the full-flow system. There is another system also in use where only a portion of the oil passes through the filter, called the bypass filter system.

The import a nce of filtering the oil is shown by the results of an investigation into the wear on the cylinder and piston, using the two filtering systems. It was found that maximum wear (100 %) occurs in engines working without an oil filter.

When a bypass filter is used, wear is reduced to about 43 % on the cylinder and 73 % on the piston, which means that the life of the piston and cylinder are almost doubled. Minimum wear occurs when a full-flow filter is used, wear is again reduced by a further 15 % on the cylinder and 22 % on the piston. This means that the life of the piston and cylinder is four to five times longer than in an engine working without a filter. A good oil filter must be capable of stopping the flow of very small particles without restricting the flow of oil through the filter. To meet this requirement different materials are used as the filtering medium. Resin-impregnated paper is widely used, the paper being folded in order to make a large surface area available for the oil to flow through; particles are left on the paper and clean oil is passed to the lubrication system.

 

Вариант 9

Disc filter is a type of full-flow filter. It is used in large diesel engines. The oil is filtered by being forced through very narrow gaps (0.05mm) between thin steel discs which form an assembly which can be rotated. The narrow gap between the discs prevents impurities in the oil from passing through. The deposits accumulate on the outside of the discs, which are kept clean by scrapers which scrape off the deposits as the disc assembly rotates. In most cases the assembly is connected to the clutch pedal; each time the pedal is operated the disc assembly is rotated a small amount. The filter must be drained as per manufacturers’ recommendations, this being done by removing the drain plug allowing dirt and some oil to be flushed out.

Again mainly found on larger engines, centrifugal filter consists of a housing with a shaft and rotor inside. The oil is forced through the inlet ports by the pump and fills the rotor through the inlet holes in the rotor shaft, passing down the pipes to the jets. Due to the force of the oil passing through the jets the rotor rotates at very high speed. Owing to the centrifugal force, the impurities (which are heavier than the oil) accumulate on the walls of the rotor. The filter must be periodically cleaned by dismantling the filter and washing with a suitable cleaning fluid.

 

Вариант 10

During combustion, when the engine is operating at full throttle, the maximum temperature reached by the burning gases may be as high as 1500–2000° C. The expansion of the gases during the power stroke lowers their temperature considerably, but during the exhaust stroke the gas temperature may still be approximately 800° C. All the engine components with which these hot gases come into contact will absorb heat from them in proportion to:

. the gas temperature;

. the area of surface exposed to the gas;

. the duration of the exposure.

For all these reasons the heat will raise the temperature of the engine components. If the temperature of the exhaust gas is above red heat it will be above the melting point of metals such as aluminium from which the pistons are made.

Unless steps are taken to reduce these temperatures a number of serious problems could arise.

1) The combustion chamber walls, piston crown, the upper end of the cylinder and the region of the exhaust port are exposed to the hottest gases and will therefore reach the highest temperatures. This will create distortion causing a leakage of gas, water or oil. It may even cause the valve to burn or the cylinder head to crack and as a consequence there will be a loss of power output.

2) The oil film will be burnt causing excessive carbon to form. The loss of lubrication of the piston and rings will cause excessive wear or the piston to seize in the cylinder.

3) Power output will be reduced because the incoming mixture will become heated so reducing its density. It may also cause detonation (this is an uncontrolled explosion in the cylinder) making it necessary to reduce the compression ratio.

 

 

Шаблон для оформления отчета №1:

 

Лабораторная работа № 1.