Figure 3-23.The parts of a piston.
examples of conditions that a piston must withstand at
The piston head is subjected to temperatures well
normal highway speed:
As the piston moves from the top of the cylinder
The structural components of the pistons are the
to the bottom (or vice versa), it accelerates from a
HEAD, SKIRT, RING GROOVES, and LANDS (fig.
stop to a speed approximately 50 mph at
3-23); however, all pistons do not look like the typical
midpoint, and then decelerates to a stop again. It
one shown here. Some have differently shaped heads.
does this approximately 80 times per second.
Diesel engine pistons usually have more ring grooves
and rings than the pistons of a gasoline engine. Some of
The piston is subjected to pressures on its head in
these rings may be installed below as well as above the
excess of 1,000 psi.
WRIST or PISTON PIN (fig. 3-24).
Figure 3-24.Diesel piston assembly.