分类：轮机英语会话
1、Pleace describe the difference between the diesel engine and the gasoline engine?
The marine diesel engine is a type of diesel engine used on ship. The diesel engine is a type of internal combustion engine which ignites the fuel by hot, high pressure air in a combustion chamber .
The gasoline engine also a type of internal combustion engine , but its combustion is completed by igniting the maixed oil gas under spark plug.
So diesel engine is compressed-burning ,and gasoline engine is igniting-burning.
2、Xiao Wang is a cadet of the engine department, who just graduacted from Shanghai Maritime University. How do you introduce all the engine room to him?
Welcom to our engine room. This is our engine room. There are many machines and devices in the engine room. Such as the main engine, suxiliary engines, donkey boiler, air compressors, pumps, supercharges and so on.This is the main engine. The mian engine on my ship is a two-stroke, low-speed, crosshead type marine diesel engine, MAN B&W 12k90MC-C with a capacity of 54720KW. There are two cooling systems in it . One is the seawater cooling system; the other is the fresh water cooling system. There are also some auxiliary machines. They are three generators, two oil separtators and a phreheater. The auxiliary engines are four-stoke, high-speed, trunk piston type marine diesel generators, YANMAR 6ML-HTS with a capacity of 270Kw. In our engine room there are many pumps, motors and valves. We , engineers and motormen, work in the engine room day and night.
3、Xiao Zhang is a three-year student of marine engineering from Shanghai Maritime University University. How do you introduce the equipment and machinery in the engine room to him?
Welcom to our engine room, We, the engineers and motormen, are doing our best to keep the ship in good order. The main engine and all the auxiliary equipemnt are home-designed and built with domestic materials. And most of the installations are automatically controlled . Our purpose for adopting automation is to guarantee high efficient operation, to ensure ship's safety and to imporove working conditions. generally speakign, our engine room is designed on the principles of safety, reliablility and practicability
Our ship is epuipped with a China-built 6ESDZ 76/160 type marine diesel engine. It has en output of 10000 horspower at 115 r/min. The cylinder bore of this diesel engine is 760 mm and the piston stroke is 1600mm. It runs either on fuel oil or on diesel oil.
This is a motor-driven two-stage air compressor and that is the vertical type oil-burning auxiliary boiler.
4、Look at the illustion and say something about the disposal of the shafting and diesel engine.
From this picture, we can see the main engine is coupled to the shaft directly. These constitute the transmission system . The transmission system on a ship transmits power form the engine to the propeller. It is made up of shafts, bearign, and finally the propeller. The differecent items in the system include the thrust shaft, one or more intermediate shafts and the tail shaft. These shafts are supported by the thrust block, intermediate bearings and the sterntube bearing.
5、Look at the illustration and say something about the probalility of disposal of medium-speed and high-speed diesel engine.
When medium-speed diesel engines are the main engine, they need a reduction speed gearbox. In the picture, there are four diesel engine. They use a common gearbox to turn the propeller. So the life of the ship is longer , you can fix one or more of them while sailing, and use main engine in turn according to the need.
6、Look at the illustration and say something about structure of the main engine.
A cross-section of a four-stroke cycle trunk piston diesel engine is shown in fig. 2-5. The engine is made up of a piston which moves up and down in a cylinder which is covered at the top by a cylinder head . The fuel injector, through which fuel enters the cylinder, is located in the cylinder head . The inlet and exhasut valves are also housed in the cylinder head and held shut by springs. The piston is joined to the connecing rod by a gudgeon pin. The bottom end or big end of the connecting rod is joined to the crankpin which forms part of the crankshaft. With this assembly the linear up-down movement of the piston is converted into rotary movement of the rankshaft. The crankshaft is arranged to drive through gears the camshaft which either directly or through pushrods operates rocker arms which open the inlet and exhaust valves. The camshaft is "timed" to open the valves at the correct point in the cycle. The crankshaft is surrounded by the crankcase and the engine framework which supports the cylinders and houses the crankshaft bearings.
7、Look at the illustration and say something about stress status of the moving parts.
From this picture, you can see the top surface of the piston and the lower surface of the cylinder cover sustained the press stress, the connecting rod sustained the press stress too. Because it is a trunk piston diesel engine, the piston will have a force to cylinder liner, i.e. the force "N"; at the same time, the connecting rod have a force to the crank, the force can break down into two forces, i.e. force "K" and force "T".
8、Look at the illustration and say the type of piston head shape in diesel engine.
From this picture , you can see the top of the piston head is not flat. It has an indent which has a certain depth. So this increases the volume of the combustion chamber, to contribute to the burning. There are four piston rang groves on the piston head, they are used for putting piston rings. This piston head is of depression top-type.