Grammar: The Gerund

Examples:

1. Supercharging increases the engine power.

/подлежащее/

2. By compressing the air charge we raise the temperature of the air.

/обстоятельство образа действия/

3. Burning is the process of uniting fuel with oxygen in the air.

/определение/

Grammar exercises

I. Substitute the Infinitives by the Gerunds:

Model: A spray nozzle is used to deliver oil in the form of a fine spray into the cylinder.

A spray nozzle is used for delivering oil in the form of a fine spray into the cylinder.

1. The air charge is compressed to increase the air temperature.

2. The temperature of the air must be high enough to ignite the particles of the injected fuel.

3. A supercharger is fitted to increase the power of an engine.

4. A two-stroke engine has a blower to obtain scavenge air.

5. The air charge is pushed into the cylinder to increase the air pressure in a four-stroke engine.

1. The two valves are designed to stay open simultaneously for about 80 to 160 degrees.

2. A slight change of the exhaust and scavenge timing is made to retain more scavenge air at the beginning of the compression stroke.

Unit VI

Text

Fuel Injection

The function of the fuel injection mechanism is to put the correct amount of fuel into the cylinder of the engine at the proper time under the right pressure and to ensure good mixing the air and the fuel for complete burning.

At present there are three principal methods of mechanical injection:

1. Direct injection or open combustion chamber method.

2. Pre-combustion chamber method.

3. Air turbulence method.

1. During the direct injection method the fuel is injected directly into the combustion chamber through a spray nozzle and under sufficient pressure. It is done in order to carry the fuel particles into the mass of the compressed air, the injector being fitted into the cylinder head.

The loss of heat during the compression is a minimum, the delay combustion period being short. This method of fuel injection gives better starting from the cold.

2. With a pre-combustion chamber method the cylinder head has a smaller combustion chamber communicating with the cylinder head through a neck.

The compressed air circulates in this chamber, at a certain moment the fuel being injected into the chamber. The fuel immediately begins to ignite. The mixture of burning and unburnt fuel passes from the pre-combustion chamber into the cylinder through the communicating neck.

3. The air turbulence method is used in several types of engines.

This method provides efficient atomizing and mixing the fuel particles with the air at the end of the compression stroke. As the volume of the injected fuel is very small in comparison with the volume of compressed air, the holes in the nozzle must be very fine and numerous. The pressure required to obtain the necessary penetration of the fuel must be very high and the sprays must have a sufficient depth of penetration to reach all the compressed air in the cylinder head.

Words

direct injection method метод прямого впрыска

pre-combustion chamber method метод предкамерного

смесеобразования

air turbulence method вихрекамерный метод

смесеобразования

sufficient, adj достаточный

particle, n частица

amount, n количество

loss, n потеря

delay combustion period период задержки

воспламенения

smooth, adj плавный

neck, n канал

mixture, n смесь

p

обеспечивать

rovide, v

insure, v

atomizing распыление

in comparison with в сравнении с

numerous, adj многочисленный

penetration, n проникновение

depth, n глубина

pass, v проходить, пропускать