Grammar: The Absolute Participle Construction

Examples:

1. Each cylinder is provided with a separate injection pump, an injection pump delivering fuel under pressure into the cylinder.

2. The delay combustion period being short, the loss of heat during the compression is a minimum.

Grammar exercises

I. Translate the given sentences paying attention to the Absolute Participle Construction. Make up two sentences as in the model.

Model:

The injection nozzle has only one hole, the injection pressure being approximately 1500 lbs per sq. in.

The injection nozzle has only one hole. The injection pressure is approximately 1500 lbs per sq. in.

1. The injection nozzle is that part of the injection system through which the fuel enters the combustion chamber, the type and the shape of it influencing the pressure, penetration and mixing of the injected fuel with air.

2. The heart of an engine is the cylinder, the fuel being burnt and the power being developed in it.

3. Many engines operate on the four-stroke cycle completed in four strokes of the piston, the engines of two-stroke cycle operating on a cycle completed in two piston strokes.

4. In a vertical diesel the cylinder stands upright, the piston moving up and down.

5. The two valves in a four-stroke engine are designed to be opened simultaneously from about 80 to 160 degrees, the selection depending upon the normal engine speed.

6. The compressed air circulates in the combustion chamber, the fuel being injected into the chamber at a certain moment.

7. The loss of heat during the compression is a minimum, the delay combustion period being short.

8. Four-stroke cycle events being completed, the cycle is repeated.

9. Each of the four-stroke cycle events taking place during one stroke of the

piston, the cycle is called a four-stroke cycle.

10. The piston passes bottom dead center, the second or compression stroke beginning.

11. A two-stroke engine has two strokes, we avoiding the intake and the exhaust strokes.

12. The fuel is badly atomized, some oxygen of the fuel being not utilized.

13. The volume of the injected fuel being very small in comparison with the volume of the compressed air, the holes in the nozzle must be very fine and numerous.

14. The piston being at the bottom of its stroke, the intake ports and the exhaust valve are open.

15. The piston being near the top of the compression stroke, the fuel is injected into the air in the combustion chamber.

Unit VII

Text

Combustion

Combustion is a chemical reaction in which certain elements of the fuel combine with oxygen of the air increasing the temperature of the gases. The main combustible elements are carbon and hydrogen. There are two general methods of burning the fuel in an engine cylinder:

1. Combustion at constant volume and

2. Combustion at constant pressure.

Combustion at constant volume means that during combustion the volume doesn't change and that all the heat energy developed by the fuel goes into an increase of the gas temperature and pressure.

The rate of combustion is so high that the piston has no time to move during combustion. Such combustion is obtained when the |piston is at the top center.

The advantage of this method is a high thermal efficiency. Its disadvantage is a sudden increase of pressure and the resulting noisiness of the engine.

During combustion at constant pressure the temperature increases at such a rate that the pressure increase counteracts the volume increase and the pressure doesn't change. The heat energy generated by the fuel goes partly into an increase of the gas temperature and partly into producing outside work.

During combustion at constant pressure the fuel is burnt gradually. The pressure attained at the end of the compression stroke is maintained during the greater part of the combustion event. Its advantage is smooth running and a more even torque produced by an engine.

High-speed diesel engines operate on a cycle which is approximately a combination of the above two methods.

Words

combustion, n горение, сжигание

combustible, adj горючий

during, prep во время

mean, v значить, означать

combine, v соединять/ся/

certain, adj определенный

oxygen, n кислород

carbon, n углерод

hydrogen, n водород

at constant volume при постоянном объеме

at constant pressure при постоянном давлении

rate, n зд. скорость

such, adj такой

obtain, v получать

advantage, n преимущество

disadvantage, n недостаток

thermal efficiency тепловой к.п.д.

sudden, adj внезапный, резкий

noisiness, n шум

counteract, v противодействовать,

уравновешивать

influence, n влияние

generate, v образовывать

attain, v достигать

maintain, v поддерживать,

обслуживать

torque, n крутящий момент

even, adj зд. плавный, равномерный

approximately, adv приблизительно

gradually, adv постепенно

smooth, adj плавный, гладкий