TM 9-2320-211-20
(3) Manner of driving expressed in speed and
rpm diagram. F o r v e h i c l e s u s e d o v e r s h o r t ;
distances, determination of speed of travel on its
own is not sufficient. Because of the speed limits
and because of traffic control, there are certain
conditions with which an operator must comply.
But the operator still has a considerable influence
on the economic running of his vehicle even though
the speed recordings may appear to show only
s l i g h t differences. Figure 2-284 shows the im-
portance of these remarks. These charts show in
each case two trips on a normal scheduled route
with economical driving and two trips with
uneconomical driving. To the inexperienced eye
there is hardly any difference between the speed
recordings. On the other hand the rpm recordings
(5) Driving up and down gradients (fig. 2-286
show the characteristic features of both types of
and 2-287). The speed chart on its own (fig. 2-
driving. While in one case rpm has been used only
286) does not lead to any conclusion as to which
within an economic range, in the other case the
gear was engaged. The rpm chart shows that the
engine has run at maximum rpm in the individual
engine was overloaded at low rpm. Damage to the
gears. There is a difference of 40 percent in fuel
engine is often the result of such handling.
consumption compared to an increase in journey
time of only 2 percent.
(4) Driving without gear engaged. This can
be recognized from the fact that individual speed
peaks extend above the maximum speed specified
(6) Traveling downhill in wrong gear. T h e
in operating instructions for the vehicle. At the
speed of travel varies constantly as a result of
same time the rpm diagram shows engine idling. If
acceleration caused by vehicle weight. When the
the engine were coupled to the wheels, rpm would
foot brake is applied, heavy stress on the foot brake
increase with speed of travel (fig. 2-285).
