b. No matter how many cylinders an engine has, whether 1, 2, 4, 6, or 12,
the same actions take place in each cylinder. Much can be learned about
construction and operation by studying a single cylinder engine (Figure 12).
This engine is a fourstroke cycle, internal combustion, gasoline engine; these
terms are explained in subsequent paragraphs.
Figure 12. SingleCylinder, FourStroke, Internal Combustion
(1) Cylinder and piston. Each cylinder of a typical engine has a
piston that reciprocates (moves up and down or back and forth) within the
cylinder and is connected to the crankshaft by a link known as a connecting rod
(Figure 13). Engine pistons transmit the force of the explosion to the
crankshaft through the connecting rod, and act as a guide for the upper end of
the connecting rod, and serve as a carrier for the piston rings used to seal
the piston in the cylinder. The top of the piston may be flat, concave,
convex, or a great variety of shapes to promote turbulence or help control