The Washington herald., 1916-05-21
CARBURETER
Often AT FAULT
Combustion Causes Heavy
Charges IN Expenditure
of Fuel.
MOTOR LEFT RUNNING
Timing of Spark and Adjustment of
Pistons, Rings and RegFinding
Cylinders Save Money.
BY asI- GRoGAN.


Though the price of gasoline is al
most double this year what it was
twelve months ago, fuel bills need be
no higher this season than they were
year ago if the car owner will take
the necessary steps to obtain more
miles per gallon Of gasoline. Automo-
bile owners, as a whole are wasteful
when II comes to the operation of their
car. II they applied the same intelli-
gence to the operation of their ma
chine that they do to running their
business, the present cost of gasoline
would have no worries for them.
Defective, poorly adjusted or incor-
rectly designed carbureters are the
root Of the greatest fuel waste. Ad-
justing carbureters so that they Will
give the maximum efficiency requires
the service OF an expert It is not
every mechanic, though he may hold
himself out as an expert, that really
understands carburetion. Many adjust
for maximum power instead OF tor
economy This means a greater fuel
consumption-a fact accounting for
much waste in itself About 1875 parts
weight Of air to one of gasoline yield
maximum power, whereas hfteen or
sixteen parts Of air to one or gasoline
give high economy whore well mixed
and fuel vapOTized.
This considerable gain in economy is
well worth the slight sacrifice In pow
sr. when one considers the rare occa-
sions where maximum power Is re-
uuired. 1t is by no means uncommon
10 find carbureters running with as lit
tie as eight parts Of air to one OF gas
olfne, a condition which prevents com
plete combustion and renders the tueI
losses large. Under such conditions
about 10 per cent Of carbon monoNluC
appears IN the exhaust--representing
: =. -, - aoproxIuately s. per cent
Of the fuel
one considerable and what may be
csI1A5 direct waste Of fuel Is the prac-
tirs Of running the motor while stano-
ing still. During this time almost az
much fuel is consumed as Is USED VT en-
running at moderate speed IN I'e 80
street. Seif-starta-s are part ol inc
CONTINENT Of all moIern machines. and
there Is no need for this waste.
There are also other factors which en-
tar into the fuel-saving question, tnousn,
NJ course. carburetion is the nrst anu
most important one.
In the four-cycle motor the maximum
thermal efficiency possible IS % per cent
though in reality 90 is the best ever OBJ
tafTed and then only under full-load con-
ditions When the charge Is throttled
and the compression pressure correspond
ingIv lowered the thermal efficiency fans
off until sometimes II Is as low as per
cent. Hence II Is important that the
compression pressure be maintained at
a maximum. and this means tight valves
and pistons-
II is worthy Of note. also, that the
hizh-speed small-bore engine which Is
zeared 10 run under ordinary conditions
with throttle we'll open Is, as result
running under good compression pressure
and therefore is inherently more econom-
ical than a larger motor which Is run FOR
a greater part Of the time rather closely
throttled.
The user cannot. Of course, control the
inherent characteristics Of the motor he
uses, but he can apply the remedies for
Ieaky pistons and valves. The valves
should be kept ground to a good seat,
their operating mechanism properly ad-
justed and the piston rings kept free.
II piston OF cylinders are worn 80 that
even well-ftted rings fail to keep them
tight new set Of pistons well fitted into
carefully reground cylinders will prove
a good investment.
4 good spark properly timed Is another
factor making for economy in fuel The
breaker or other device for timing the
spark should be kept in proper adjust
ment and the spark carried as far ad-
vanced as is possible without causing the
motor to labor.
To develop power it is necessary to burn
fuel, hence wasted power means wasted
fuel Obviously, then, it Is very desira-
bic to minimize power losses. A very
large percentage OF the power developed
by an automobile engine is utilized Cor
perhaps we would better say losD in
overcoming frictional resistances within
the car. This loss cannot be entirely
eliminated. but II should be reduced to
and kept at minimum. Not only will
this result in a saving Of fuel but IL
will leave available for accelerating the
car, hill climbing, and overcoming wind
resistance more power than would 9TH
erwise be left for this purpose.
The greatest frictionaT loss in the
motor is that due to pressure of the
pistons and rings against the cyIin-
der walls. Obviously these parts