Tài liệu Lesson 11-Marine Diesel Engines (2) pdf

Lesson 11-Marine Diesel Engines (2)

For better understanding of a whole diesel engine, it is quite necessary to have some

idea about the operation or purpose of diesel engine parts. Each part or unit has its own

special function to perform and in conjunction with the other parts constitutes a diesel

engine. Those who want to operate, repair or assemble diesel engines must be able to

recognize different parts by sight and know what their particular functions are.

With different number and arrangement of cylinders, diesel engines vary in their

outer appearance and size as well as in the details of construction. However, they all have

the same main parts which, though the parts may look different, will perform the same

functions. By parts each diesel engine can be separated into fixed parts and moving parts.

Roughly speaking, fixed parts refer to the bedplate which rests on a hull structure termed

as engine foundation or engine seat, engine frame, cylinder block and cylinder cover (or

cylinder head), while moving parts include piston, connecting rod and crankshaft. The

following is a brief introduction on the main parts of a diesel engine.

1. Bedplate

It is to be steel plate welded, and subjected to different forces such as inertia and

impact of the moving parts apart from supporting the whole weight of a diesel engine.

Besides, forces exerting on the bedplate will become more complicated owing to hull

deformation when a vessel is sailing at rough sea. Needless to say, a bedplate must both

be strong enough and sufficiently rigid. On a bedplate there are bearing holes for fitting

Fig. 11.1

1-connecting rod thanh truyền ; 2-piston; 3-cylinder head đầu xylanh; 4-nozzle vòi phun ;

5-indicating valve van chỉ thị ; 6-exhaust valve van xả; 7-cooling water nước làm mát ; 8-

cylinder head casing hộp đầu xylanh ; 9-high-pressure oil pump bơm dầu cao áp ; 10-

casing; 11-bedplate bệ máy ;l2-camshaft trục cam ;l3-mainbearing ổ đỡ chính ; 14-crank

shaft trục khuỷu; 15-speed governor cái khống chế tốc độ ; 16-flywheel bánh đà