The Oil Engine 237
then pass to the
various purposes
for which Diesel
engines are used.
The general ar-
rangement will be
understood from
Figs. 132 and 133.
In the first
place, Diesel en-
gines are generally
made vertical, be-
cause all the
reasons which can
be advanced in
favour of vertical
steam engines and
some others are at
least equally appli-
cable to Diesel
engines. Secondly,
the type most
usually met with
is a four-stroke
engine, in which
the piston receives
one impulse in
every two revolu-
tions of the fly-
wheel. The first
outward stroke of
Fig. 133.—Longitudinal section of
Diesel engine