Pressure – charging

Pressure – or super – charging is a process of increasing the power output of an engine. If during the working cycle the amount of air supplied into the cylinder is increased it will enable to burn more fuel and as a result more power is received (achieved, obtained). To supply more air it should be compressed. The air is compressed by a turboblower installed just after the engine. This turboblower consists of a compressor and a turbine which is driven by the exhaust gases leaving the engine.

The exhaust turboblower system increases the total efficiency of the engine, its reliability and reduces the maintenance costs.

There are two types of the turbo-charging system. The main engines can operate on the pulse or impulse system and constant-pressure system (the system producing constant pressure of the exhaust gases). With impulse system the construction is rather complicated. It means that engines with more than three cylinders must be fitted with more than one turboblower or the turboblower must have multi-inlet casings which have separate passages to the turbine nozzles. And the efficiency of the turbine reduces. But this system is highly efficient at partial loads of the engine operation.

For constant pressure operation all cylinders exhaust into a common receiver (manifold) where the constant pressure is maintained (kept). The construction is simplified. It allows greater flexibility in positioning the turboblower. But the system is insensitive to changes in engine operating conditions (The system is less efficient at part-load conditions).

amount	[q'mQunt]	количество
enable	[i'neibl]	смочь, быть способным
burn	[bWn]	сжечь
receive	[ri'sJv]	получать
installed	[in'stLl]	устанавливать
drive	['drQiv]	приводить(в движение)
reliability	[ri"laiq'biliti]	надежность
maintenance	['meintinqns]	эксплуатация
costs	[kOsts]	расходы
constant	['kOnstqn]	постоянный
mean	[mJn]	означает
multi-inlet	[mAlti 'inlet]	с несколькими входами
separate	['seprit]	отдельный
nozzle	[nOzl]	сопло
partial	['pRSql]	частичный
common	['kOmqn]	общий
simplify	['simplifQi]	упрощать
flexibility	["fleksi'biliti]	гибкость
insensitive	[in'sensitiv]	нечувствительный

Тематика экзаменационных тем для проверки навыков говорения.

1. Marine Internal Combustion Engine. Construction and principle of operation of four - stroke cycle engines.

2. Marine Internal Combustion Engine. Construction and principle of operation of two- stroke cycle engines.

3. The process of scavenging: purpose, methods, advantages and disadvantages.

4. Supercharging: its purpose, arrangement and advantages. Two systems of turbo-charging: advantages and disadvantages.

5. The fuel system of Diesel engines: its components, functioning, possible troubles.

6. Diesel engine cooling system: its components, purpose, functioning and possible troubles.

7. The purpose of lubricating. The principal parts of the lubricating system of a Diesel engine.

8. Fuel treatment. Types of separators.

9. Failures to the engine, the ways of their elimination.

10. Ship’s organization, engine department.

11. Marine engineers’ duties, watch keeping.