Lesson 7 advantages of the diesel over the gasoline engine

The diesel engine can compress the air to much greater pressure than the gasoline engine can compress the fuel and air mixture without excessive detonation is due to several factors among which briefly, are the fuels used and the methods employed in combustion of the fuels.

The gasoline air mixture present during compression in a gasoline engine is a highly combustible compound and would ignite with very little heat of compression. It is because of the presence of the fuel during compression stroke so that compression ratios of gasoline engines must be kept low.

With the diesel engine, air alone without a fuel mixture is compressed, and therefore there is nothing to pre-ignite. As the injection of the fuel oil is controlled by the timing of the injection pump, its ignition takes place only when it is desired and not before. Complete combustion of the fuel is assured when all the fuel combines with the air; so there is always provided more air in the cylinder then it is necessary to burn the measured charge of fuel oil.

Besides a diesel engine uses low-cost fuel oils, and on account of the higher efficiency of its working cycle, burns them more economically than could be done in a carburetor engine, even if satisfactory method of carbureting these heavy oils could be devised. Further, a well-designed modern diesel engine delivers a greater proportion of the theoretical work value of the fuel than does the gasoline engine. Fuel as we know, has a certain heat value, and heat its work, thus the diesel is said to have the higher thermal efficiency which in term of ordinary usage means that the diesel turns more heat into power and wastes less in cooling water and exhaust gases. This is a big saving where the engine is used under load for a number of hours where there are a great number of units operating daily.

Since automotive diesel engines are invariably high-speed engines, the true diesel form progressive, moderate speed, constant pressure combustion is never realized. The time permitted for the whole combustion process to take place in an engine operating at 1.800 rpm, is less than 1/300 th of a second. But in spite of this similarity to the gasoline engine, because of the higher compression ratios possible and the excess air in the combustion chamber, the torque of the diesel engine is more uniform than that of the gasoline, and its ability to pull at low speeds is much greater.

Plenty of air, turbulence, and atomizing or gasifying the fuel charge are the major factors contributing to the complete combustion of the fuel charge in a diesel engine.

Задание 1. Образуйте существительные от следующих глаголов с помощью суффиксов -ance, -ence.

-ance: appear, assist, attend, perform, accord, enter;

-ence: differ, depend, refer, exist, correspond.

Задание 2. Прочитайте и переведите следующие слова и словосочетания на русский язык.

Air mixture, detonation, compression ratios, to employ, the charge of fuel oil, heat value, moderate speed, thermal efficiency, to deliver, the timing of the injection pump, exhaust gas, the major factors, to contribute, the ordinary usage, satisfactory method, the whole combustion process, proportion, the torque of the diesel engine, combustible compound.

Задание 3. Дайте английские эквиваленты русских слов в скобках.

1. It is because of the presence of the fuel during (такт сжатия) so that compression ratios of gasoline engines must be kept low.

2. The injection of the fuel oil is controlled by the timing of (топливный насос), its (воспламенение) takes place only when it is desired and not before.

3. Plenty of air, turbulence, and atomizing or gasifying the fuel charge are (основные факторы) contributing to the complete combustion (сгорание полностью) of the fuel charge in a diesel engine.

4. Besides a diesel engine uses (дешевые) fuel oils, and (вследствие) the higher efficiency of its working cycle, (сжигает) them more economically than could be done in a carburetor engine.

5. Complete combustion of the fuel is assured when all the fuel (смешивается) with the air.

Задание 4. Задайте друг другу вопросы по тексту, пользуясь следующими косвенными вопросами. Получите ответы на ваши вопросы.

1. Ask him/ her how the diesel engine can compress the air.

2. Ask him/ her how the injection of the fuel is controlled.

3. Ask him/ her what the diesel engine is said to have.

4. Ask him/ her what the time permitted for the whole combustion process is.

5. Ask him/her what a well-designed modern diesel engine delivers than the gasoline engine does.

6. Ask him/ her how the engine is used under load.

7. Ask him/ her why the compression ratios of gasoline engines must be kept low.

Задание 5. Вместо пропусков вставьте подходящие по смыслу предлоги, данные в скобках, переведите предложения на русский язык.

1. …this similarity to the gasoline engine, … the higher compression ratios possible and the excess air in the combustion chamber.

2. …the control of the fuel oil, its ignition takes place only when it is desired and not before.

3. …the diesel engine, it can compress the air to much greater pressure than the gasoline engine can compress the fuel.

4. Complete combustion of the fuel is assured when all the fuel combines with the air; so there is always provided more air in the cylinder then it is necessary to burn the measured charge of fuel oil.

5. … low-cost fuel oils, and the higher efficiency of the working cycle of a diesel engine, it burns the fuel oils more economically.

6. … see that the automotive diesel engines are invariably high-speed engines we should take into account the time permitted for the whole combustion process.

7. … obtain all these qualities engineers should develop up-to-date methods of designing cars, using new types of resistant to corrosion light materials.

8. … to automobile designing the automobile consists of three parts: the power plant, or the engine, the chassis and the body. To these may be added the accessories (вспомогательные устройства): the heater, lights, radio, speedometer and other devices.

( In spite of, due to, in order to, thanks to, according to, because of, as for.)

Задание 6. Переведите текст на английский язык.

1. Из первичных двигателей самое широкое распространение получили тепловые двигатели, превращающие в механическую работу энергию, получаемую при сжигании различных твердых, жидких и газообразных видов топлива.

2. Первый работоспособный двигатель был построен французским механиком Ленуаром только в 1860 году.

3. Широкое практическое применение двигатели внутреннего сгорания нашли лишь после того, как немецкий механик Отто в 1877г. осуществил предварительное сжигание смеси в цилиндре, благодаря чему эффективность таких двигателей резко повысилась.

Задание 7. Составьте план текста и расскажите о преимуществах дизельного двигателя по этому плану.

TEST YOURSELF

Прочтите и переведите текст на русский язык без помощи словаря и выполните следующие за ним упражнения.

The engine is the source of power that makes the car move. The operating cycle of the four-stroke engine that takes place in the engine cylinder can be divided into four strokes. The upper limit of the piston movement is called the top dead center. The low limit of piston movement is called the bottom dead center. A stroke is the piston movement from the top dead center to the bottom dead center, or from the bottom dead center to the top dead center. In other words, the piston completes a stroke each time it changes the direction of its motion. Where the entire cycle of events in the cylinder requires four strokes (two crankshaft revolutions), the engine is called a four-stroke cycle engine. The four strokes are: intake, compression, power and exhaust.

In two-cycle engines the entire cycle of events is completed in two strokes or one revolution of the crankshaft. On the intake stroke the intake valve is opened. The mixture of air and vaporized gasoline is delivered into the cylinder through the inlet valve.

On the compression stroke the inlet valve is closed so that the mixture can be compressed. On the power stroke both valves (inlet and exhaust) are closed in order to rise pressure during the mixture combustion. On the exhaust stroke the exhaust valve is opened to exhaust the residual gas.

1. Найдите в правой колонке русские эквиваленты английских слов и словосочетаний.

1. stroke	a. поршень
2. piston	b. верхняя мертвая точка
3. top dead centre	c. четырехтактный двигатель
4. bottom dead centre	d. коленчатый вал
5. four-stroke cycle engine	e. отверстие клапана
6. two-cycle engine	f. нижняя мертвая точка
7. crankshaft	g. такт впрыска (топлива)
8. intake stroke	h. топливная система
9. valve operating	i. ход, такт (поршня)
10. fuel system	j. выхлоп
11. power stroke	k. двухтактный двигатель
12. exhaust	l. рабочий ход поршня