Combustion chamber

The combustion chamber is the space within the cylinder above the piston where the burning of the gas occurs.

Since early days of the industry research is continued on the design characteristics of the combustion chamber.

The trend in design has been, and is, to concentrate as much of the expansive force as possible directly on the head of the piston and avoid dissipation of the expansive force in directions that do not produce power.

Another trend is towards the creation and control of turbulence or movement of the air and gasoline mixture within the cylinder to create a more uniform and better mixture of the gasoline and air. It has been recognized for many years that the more the explosive mixture is compressed within the cylinder before it is ignited, the more power will be developed by the explosion stroke.

The amount of power depends also upon the characteristics of the fuel used. One of these characteristics is the tendency of the fuel " to ping" or " knock" as the compression pressure is raised. This knocking, known as detonation, is attributed to irregular and to rapid expansion of explosion of the gasoline and air mixture.

The noise comes from vibration of the walls of the combustion chamber.

The material of which the combustion chamber is made and the efficiency of the cooling system also has a distinct bearing on the compression ratio that can be used in a given engine.

For example, aluminium pistons and aluminium cylinder heads can operate at higher compression ratios than could cast iron or steel.

One reason for this is perhaps that the heat of combustion is dissipated more rapidly to the cooling water due to the superior heat conducting ability of aluminium. Aluminium can be used for cylinder heads as the cylinder heads in practically all modern engines are detachable.

Aluminium would not be suitable for the engine cylinders as it is too soft to wear well. In the early days individual cylinders were sometimes made of cast iron with a copper outer jacket or water jacket attached to them, as copper is also an excellent conductor of heat. This construction was expensive and would also be impractical for modern engines, where cylinders are cast in blocks.

It is entirely practical to make the cylinder casting inclu­ding the water jacket out of aluminium and insert a cast iron cylinder sleeve or barrel inside the aluminium. This is an ехсellent arrangement where the cost of aluminium makes this construction economically feasable. An aluminium cylinder block with cast iron sleeves in combination with aluminium cylinder head and aluminium pistons provides excellent heat dissipation and anti-detonation qualities.

Задание 4. Закончите следующие предложения, используя текст.

1. The combustion chamber is...

2. Since early days the industry research is continued on…

3. The trend in design is to concentrate as much of the expansive force as possible directly on...

4. Another trend is toward the creation and control of...

5. The amount of power depends also upon...

6. The material of which the combustion chamber is made and the efficiency of the cooling system also have a distinct bearing on...

7. Aluminium would not be suitable for the engine cylinders as...

Задание 5. Образуйте существительные от следующих глаголов:

burn, continue, concentrate, dissipate, produce, create, move, mix, develop, depend, tend, press, detonate, vibrate, conduct, detach, combine.

Задание 6. Найдите ответ, соответствующий содержанию текста.

1. What do we call a combustion chamber?

2. For what purpose is the turbulence within the cylinder created?

3. What is the relation between the compression and the power?

4. Upon what does the amount of power depend?

5. Of what material can cylinders be made?

Задание 7. Передайте содержание текста на английском языке, используя следующий план.

1. The purpose of the combustion chamber.

2. The ways of the developing power

a) design characteristics;

b) compression ratio;

c) characteristics of the fuel;

d) the material of which the combustion chamber is made;

e) the efficiency of the cooling system.

При ответе используйте следующие выражения:

the text is about...; the text deals with the problem of...; the main problem of the text is...; it should be noted that...; I know, that...; it is worth mentioning.