Контрольная работа №4 вариант 5

I. Translate the text into Russian.

A few remarkable differences between the two-stroke and four-stroke cycles

In the two-stroke cycle there is a combustion process for every revolution, whereas in the four- stroke cycle there is one for every two revolutions.

Theoretically, a two-stroke engine with a similar cylinder capacity and rpm should have twice the power output.

In the two-stroke cycle the exhaust gases flow out of cylinder under an over-pressure, at the same moment that the piston releases the inlet port, the air supplied must have an over-pressure in relation to the exhaust gas pressure, otherwise the exhaust gases will flow back into the cylinder! The two-stroke engine requires an air supply that has a pressure exceeding that of the exhaust gas pressure and therefore far higher than atmospheric pressure (over-pressure).

In very small two-stroke engines the bottom part of the piston in conjunction with the smallest possible crank case functions as a scavenge pump. In slightly larger two-stroke engines a scavenge pump for the air supply is driven by the crank shaft. In industrial engines the scavenging air is always supplied by a turbo blower.

In the four-stroke cycle all stages are executed by the piston:

- intake;

- compression;

- power;

- exhaust.

This is a simpler process. Additionally, the exhaust gases are far better expelled.

II. Read the following definitions and find the corresponding terms, which they explain. Translate completed sentences into Russian.

Air density ratio.	The volume of a compression chamber with the piston at the top of its stroke as a proportion of the total volume of the cylinder when the piston is at the bottom of its stroke.
Naturally aspirated	The volume of a cylinder displaced by a piston in one complete stroke (i.e., from the bottom to the top of its cylinder).
Boost pressure ratio.	The change in density which occurs when the temperature of the air rises when undergoing compression.
Compression ratio.	Refers to an engine that draws in air solely by the action of its pistons, without the help of a supercharger or turbocharger.
Swept volume.	The pressure rise across the air section of the turbo-blower.

III. Write the full forms, in words, of the abbreviations and shortened terms below and translate into Russian.

abbreviation	the full form	translation
DE	Diesel engine	дизельный двигатель
EC
IC
SI engine
CI engine
SHP

IV. Put the words in the right order to form a question.

1. fuel what injection system functions does perform?

2. parts fuel and system what fill does transfer consist of?

3. heavy what coils the fuel tanks are with for oil provided?

4. tank to fuel responsibility is a transfer storage a from tank to settling whose oil?

5. oil HFO through why strainer flow fuel a does and heater?

V. Translate from Russian into English.

1. Рабочий цикл двухтактного двигателя осуществляется за два хода поршня - за один оборот коленчатого вала и состоит из таких же процессов, что и рабочий цикл четырехтактного двигателя.

2. Первый такт. Поршень идет вверх, сжимая топливную смесь в камере сгорания. Происходит воспламенение смеси (не достигая ВМТ). Когда поршень находится в ВМТ, впускные окна в стенке цилиндра открыты, топливная смесь поступает в кривошипную камеру.

3. Второй такт, рабочий ход. Расширяющиеся газы толкают поршень вниз. Когда он находится внизу, он открывает выпускные и впускные окна. Так как газы выходят в сторону меньшего сопротивления, т.е. в выхлопную трубу, их место занимает топливная смесь, поступающая из кривошипной камеры, где смесь находится под давлением.

4. При этом выпуск газов из цилиндра осуществляется не выталкиванием их поршнем, а путем продувки цилиндра воздухом, подаваемым в него под давлением, создаваемым продувочным насосом или турбокомпрессором.