Vocabulary note:

12. shaft horsepower – мощность по валу

13. ratio – передаточное число

14. starting difficulties – проблемы при запуске (двигателя)

15. indicated horsepower – номинальная мощность

16. friction – трение

17. fit – подгонка

18. clearance – зазор

Exercise 2. Read and translate the text.

Upon first sight the Diesel engine is apt to create the impression that it is a very complicated mechanism, but a little analysis will reveal that it is actually more simple than the steam plant. Comparing the two it should be born in mind that the steam engine alone is not a usable machine; to be able to use it we must have a boiler and all the attendant mechanisms, including pumps, piping, water tanks, condenser, etc., and the complete steam plant becomes quite a complicated thing. The Diesel engine, on the other hand, may be arranged so that all of the apparatus required in its operation as a power plant may be attached directly to the engine itself.

Perhaps the most striking difference in the problem of maintenance of the Diesel engine as compared to steam engine maintenance arises from the fact that the steam engine can be allowed to fall, more or less gradually, into a very bad state of disrepair and will continue to run but the Diesel engine must be pretty nearly right or it will not run at all.

The derangements likely to occur in operation and the adjustments required to correct them may be grouped into the following general classes:

a) Wrong fits and clearances, looseness and tightness of parts.

b) Mechanical defects.

c) Fuel system defects.

d) Combustion defects.

e) Cooling water system defects.

f) Lubricating system defects.

g) Air system defects.

8. Starting difficulties.

9. Operating troubles in general.

Exercise 3. Answer the following questions.

1) What impression is the Diesel engine apt to create upon first sight?

2) What should be born in mind when comparing the Diesel engine and the steam engine?

3) What is the most striking difference in the problem of maintenance of the Diesel as compared to steam engine maintenance?

4) What conditions are necessary to make the Diesel run at all?

5) What classes of derangements likely to occur do you know?

6) What mechanisms we must have to run a steam engine?

7) What is the aim of grouping the derangements likely to occur in operation into 9 general classes?

8) What advantages and disadvantages has each of these (diesel and steam) engines?

Exercise 4. Translate into English.

1. На первый взгляд дизель может показаться очень сложным механизмом, но небольшой анализ покажет, что в действительности он значительно проще, чем паровая машина с котлом, вспомогательными механизмами, конденсаторами и т. д.

2. Неисправности, которые чаще всего встречаются в эксплуатации, могут быть классифицированы следующим образом: а) механические дефекты; b) неправильные зазоры; с) плохая пригонка и т. д.

3. Если возникнут неисправности во время эксплуатации, следует принять необходимые меры по их устранению.

4. Для того, чтобы дизель работал он должен находиться в исправном состоянии, иначе его работа невозможна.

5. Сравнивая дизельный и паровой двигатели нужно заметить, что сам по себе паровой двигатель не является рабочим механизмом.

6. Чтобы иметь возможность использовать паровой двигатель нужно множество вспомогательных механизмов, котлы, насосы, танки для воды, конденсаторы и многое другое.

7. Готовая к использованию паровая силовая установка представляет собой сложный механизм.

8. Дизельный двигатель может быть скомпонован таким образом, что все устройства, необходимые для его работы как силовой установки, могут быть подключены непосредственно к самому двигателю.

Exercise 5. Make up a dialogue of your own based on the one given below.

A.: What is the power available at the shaft called and how is it measured?

В.: Shaft horsepower, or brake horsepower. It is usually measured by attaching some form of brake to the shaft and measuring the amount of power absorbed by the brake when the engine is running. A second method is to attach an electric generator to the shaft and measure the electrical output of the generator.

A.: Is the mechanical efficiency, or the ratio between brake horsepower and indicated horsepower, the same at all loads?

В.: No. The power absorbed in friction in the engine is the same at all loads and as the engine load decreases the ratio of B.H.P. to I.H.P. decreases.

A.: What auxiliary machinery is usually found in the engine-room of a motorship?

В.: Jacket cooling water pumps, raw water pump, piston cooling pumps, lubricating oil pumps, fuel oil service pumps, bilge and ballast pumps, engine-room bilge pumps, fresh water pump, auxiliary air compressor. Diesel electric generating sets, donkey boiler, evaporator and distiller, boiler and evaporator feed pumps, emergency compressor, ice machine and oil separator.

A.: What auxiliary machinery is used on deck?

В.: Deck winches, anchor windlass, capstans, steering engine, air whistle and lighting system.

A.: How are Diesel engines started?

В.: By running as air motors, on compressed air at medium pressure, until ignition of fuel occurs and operation as a combustion motor starts,

A.: How is the starting air obtained and where is it stored?

В.: By means of a compressor attached to the engine or an auxiliary air compressor driven by a Diesel engine, electric motor or steam engine. It is stored in large tanks, usually suspended under the deck in the engine room.

A.: From what other source can air for filling the starting tanks be obtained?

В.: On engines of the air injection type the injection air compressor attached to the engine usually has a capacity greater than that required for supplying injection air. The excess air may be by-passed to the starting tanks through a connection provided for that purpose.

Comprehensive reading. Read, translate into Russian and discuss the following text.

Diesel electric propulsion systems

As a concept, diesel electric propulsion (DEP) is not new. Diesel Electric Systems have been in use to propel vessels for more than 100 years. If we analyze marine construction over the last 3 years, we can see that investment in DEP vessels have doubled, while the construction of purely mechanically propelled vessels has slowed down.

Diesel-electric propulsion provides many propulsion options and advantages. The first is efficiency by being able to run appropriately sized diesel-engine generators based on demand versus a large diesel engine often idling along and that leads to better control of emissions. Many of our ship diesel-electric designs use multiple engines of different sizes. With combinations of small, medium and large diesel generators, you are able to bring on power in small increments to keep the engines at appropriate loadings and operating at their highest efficiencies.

Noise and comfort are big design issues, but it's not solely related to diesel-electric or not. A traditional shaft line running to the engine, which is hard mounted to the ship, will produce more vibration and noise. A generator set is an isolated piece of machinery, and that benefit is it can be vibration-isolated.

The big low-speed diesel engines with the gear boxes and shaft lines to the propeller are located deep down in the hull. With diesel-electric, the diesel engines and generators can be put higher up, giving the operating benefits of less ducting for air intakes and exhausts that also takes up less space within the vessels. It also allows a better distribution of the equipment.

Exercise 6. Discuss the following topics.

1. Reasons of derangements in operation of engines.

2. Of what factors the choice of engine (diesel/steam) depends on?

3. Comparison of steam and diesel engines (advantages and disadvantages).

4. For how long Diesel Electric Systems have been used?

5. What are the advantages of diesel-electric propulsion?

6. Explain why different sizes of diesel generators are so important.

7. What should be done in order to reduce noise and vibration?

Watch the video “Marine Diesel Engines– Coolant Troubleshooting & Maintenance” and discuss the following topics. [https://www.youtube.com/watch?v=I8IG1wtWs4Y]

1) Auxiliary machinery usually installed in engine room. Discuss the functions of this machinery.

2) The process of Diesel engine's starting.

3) Auxiliary machinery usually used on the deck. Discuss the functions of this machinery.

Lesson 3. WRONG FITS AND CLEARANCES

Exercise 1. Read and learn the following words and expressions:

Synonyms:

1. design/construction - конструкция

2. to investigate / to consider / to examine – рассматривать, расследовать

3. volume/ capacity / bulk – емкость, вместимость

4. to discharge / to use up / to run down – разряжать

5. to develop / to evolve / to expand – развивать, расширять

6. jaw – фиксатор / зажим