Атрибутивная цепочка (цепочка определений)

Suction valve, plate type.

Suction valve of plate type

Plate type suction valve

Plate type suction valve with spring loaded ring

Spring loaded ring plate type suction valve.

Internal combustion engine, vessel bottom framing, engine stationary parts, connecting rod small end bearing, engine exhaust valves, engine inlet valves, engine intake manifold.

1. The mixture formation specific feature in diesels built at the beginning of last century is that fuel was introduced into the cylinder and atomized with the aid of compressed air and burnt in it without any noticeable increase in pressure, i.e., at an approximately constant pressure.

2. The four-stroke Diesel engine design and operating principles described in this text deepen the theoretical knowledge of the 4-year cadets studying at the marine engineering faculty.

Engines

There are two main types of the engines: Otto engines and Diesel ones. The engine operating on heavy fuel is called Diesel engine or internal combustion engines. The heavy fuel is injected in atomized state into the cylinder at the end of the compression stroke and ignites spontaneously in the hot compressed air. Each engine consists of (has) moving and stationary parts. The stationary parts are: cylinder liners and cylinder heads, block of cylinders, a crankcase, a bed plate, a frame. The main moving parts are: a crankshaft, a connecting rod, a piston, bearings and valves.

There are two types of the ICE four-and two-stroke diesel engines. The working cycle of the four-stroke engine is completed during four strokes of the piston. During the first stroke the position of the piston is at top dead centre and the intake valve is open. The piston moves down and air enters the cylinder liner. This stroke is called suction stroke. During the second stroke the piston moves upward, all the valves are closed and air is compressed. As a result of the compression the temperature and pressure are increased. This stroke is a compression stroke. At the end of compression stroke the injector supplies some atomized fuel into the cylinder. The process of combustion starts. The gases expand and push the piston downward. This stroke is called a combustion stroke. The fourth stroke is exhaust stroke during which the piston goes up discharging all products of combustion out of the cylinder through the opened exhaust valve. At the same time the crankshaft makes two revolutions completing the cycle.

With two-stroke engines the working cycle is completed in two strokes of the piston and one revolution of the crankshaft. There are some differences in construction of the cylinder liners. With this construction the liners have scavenge and exhaust ports instead of valves.

The cycle starts when the piston is at its bottom dead centre and the ports are completely open. Here scavenging takes place that continues until the piston moves upward and closes the scavenging ports. Then the piston closes the exhaust ports and the air in the cylinder is compressed. When the piston is at the top dead position injection of the fuel takes place and process of combustion occurs. The products of combustion expand. The piston moves down opening the exhaust ports and the exhaust gases leave the cylinder. Then the piston opens the scavenge ports and fresh air rushes into the cylinder taking away all remaining products of combustion.

Theoretically, with the same size of the cylinder and an equal speed a two-stroke engine can develop a power two times that of a four-stroke engine.