The Washington herald. [volume] (Washington, D.C.) 1906-1939, 1922-01-01

F. To develop maximum power at
any throttle opening above one
quarter load, a mixture of Is parts
OF air to ! of gasoline is necessary.
This Is the leanest mixture that
can be used without cutting down
the power of the engine. II the
mixture temperature is increased
to 100 degrees F., the point of
highest power remains at 1871 but
the curve is so changed that a
ratio of 1881 can be successfully
employed. Thus a small change Of
temperature will allow a saving Of
10 per cent of the fuel used. Many
cars are adjusted to run on nearly
1O:1 ratio as this will give. good
performance but very low mileage
Two cars Of the same model may
thus give entirely different results
in mileage even though the heat
regulation is identical.
The mixture requirements for
high power and efficiency in brief
are: Above quarter load an air
fuel mixture of 1871 will give good
power. Below this point a slight
ly richer ratio of l2.2:l Is neces-
sary. Below quarter load the point
of highest efficiency lies quite close
to that of power. Above this
value. however, the efficiency peak
is on the lean side of power point.
In all cases a carburetor can be
adjusted as lean as possible for
power and no decrease in thermal
efficiency will be occasioned. An
adjustment can be made that will
fall between the power and eff
cheney maximum values. This
ratio Will give good acceleration
and power and also the highest
thermal efficiency available with
out undue loss 10 the Juggling
capacity Of the engine.
The perfect carburetor is yet to
be invented. Some are more en-
pensive than the initial cost would
indicate. Many cars use a meter
ing device such that every time
the speed is changed, the adjust
ment should be changed. No one
can use fuel economically in that
case, unless a uniform speed is
maintained and the carburetor ad-
justed at that place. If an in
strument can be obtained that will
give nearly constant mixture
ratio then little trouble will be
experienced once II is adjusted
correctly. For maximum economy,
the present type OF carburetor
needs a dash or steering column
control.
II the mixture is correct when
the engine is cold, then when it is
warmed the ratio is too rich. Some
means should be provided for en-
riching the mixture until the car
mas warmed, then the mixture can
be made leaner until the power is
just noticeably affected. A portion
of the public will not use such a
manual device even though IL is
a matter of more than % per cent
of the fuel bill. The ideal plan is
the automatic operation for this
change. and as the temperature
conditions change, the ratio may
follow the requirements necessary.
In making the main adjustment
on the carburetor, the following
VIII give good economy with good
operation: Allow the engine to
thoroughly warm, then with the
speed at some medium value turn
the adjusting nut in the lean di-
rection until the engine slows
down and possibly backfires. Now
enrich the mixture until the engine
has attained its highest speed. This
is the high power point Good
operation can be had at a leaner
value, so lean the mixture until the
speed is cut a trif1c. This will i
give a good operating mixture for
both power and economy. To check
the constancy of mixture ratio de-
livered by the carburetor drive the
ear at your accustomed speeds and
" a change is necessary compcn-
safe by means of. the dash adjust
ment II so equipped. If not. then
adjust as before except on the
road at the desired speed.
A few moments attention and
less trouble will be experienced
with sooted plugs, carboned COM
oustfon chambers, and pitted
valves. Crank case dilution will be
reduced to a minimum when a
warm mixture is used. Cars driven
by the average operator and ad-
justed for warm conditions with a
correct mixture ratio, have shown
from 40 to 100 per cent gain In
mileage. In addition no plug
trouble has been experienced due
10 carbon. Thus the average owner
can install a stove or increase the |
area of the small one supplied, and |
with little care in warming, the |
excess fuel used can be reduced to |
4 minimum.-The American Auto |