Internal combustion 4 cycle engine
The scavenging ports are in communication with a passage leading to a low pressure scavenging air compressor, operated from the engine. In place of air inlet valves there are scavenging ports, in place of exhaust valves there are exhaust ports, in uniflow scavenging engines there are exhaust valves. The spray valve and starting valve are the same as in the 4-cycle. In the 2-cycle, single acting Diesel engine instead of an exhaust valve there is a ring of exhaust ports around the bottom of the cylinder, communicating with the exhaust pipe. It is thus seen that one complete cycle requires four strokes of the piston the four strokes comprise two complete revolutions of the crank. At the end of this stroke the exhaust valve closes, the air inlet valve opens and the cycle of operations starts again. Returning on the fourth, or exhaust stroke, the piston pushes the remaining gas out of the cylinder. At the end of this stroke the exhaust valve opens and the burned gases in the cylinder, now reduced to about 40 pounds pressure, and correspondingly reduced in temperature, start to flow out through the exhaust pipe. The injection valve closes shortly after the piston has started down on this stroke. In the meantime, the piston has started down on the third, or expansion stroke, with the gas expanding behind it. This burning raises the temperature of the gas to approximately 3,000F. The high temperature of the compressed air in the cylinder ignites the fuel, and it continues to burn as long as injection is maintained. The fuel injection valve now opens and the fuel is sprayed into the cylinder under a pressure of 3,550 p.s.i. At the end of this stroke the air has been compressed to about 480 pounds and its temperature has risen to about 1,000 degrees F. … and as the piston rises on the second, or compression stroke, the air in the cylinder is compressed. The exhaust valve, fuel valve are all closed. The air inlet valve is open and air is being drawn into the cylinder through the air inlet pipe. The piston starts a downward, suction stroke. The four-stroke cycle consists of: the suction stroke, compression stroke, combustion and expansion stroke and exhaust stroke. The engines of either type may be single or double acting, trunk-piston type, crosshead type, opposed-piston type. »Ĭycles of Diesel EngineAny internal combustion engine, regardless of principle it operates on, is said to have a four-stroke cycle or a two-stroke cycle. «Cycles of Diesel EngineAny internal combustion engine, regardless of principle it operates on, is said to have a four-stroke cycle or a two-stroke cycle.