Page 21 - Introduction to Marine Engineering

Diesel engines 9

Inlet
valve Exhaust
alve

Cylinder Cylinder

Connecting rod

(b)

Fuel injector

Figure 2.1 The four-stroke cycle, (a) suction stroke and (b) compression stroke, (c) power
stroke and (d) exhaust stroke

The two-stroke cycle is completed in two strokes of the piston or one
revolution of the crankshaft. In order to operate this cycle where each
event is accomplished in a very short time, the engine requires a number
of special arrangements. First, the fresh air must be forced in under
pressure. The incoming air is used to clean out or scavenge the exhaust