New Britain herald., 1923-08-18
ALTER CARDURETOR
and SAVE GASOLINE
Bureau Of Mines Conducts Tests
on Exhaust Gases

Washington, Aug Substantial
savings OF gasoline by the periodical
adjustment OF carburetors based on
the results OF analysis OF exhaust gases
from automobile engines are declared
to be feasible by the Department OF
the Interior following experiments by
the Bureau of Mines on the fleet of
motor trucks used by the Government
Fuel Yard In Washington. As the re-
suit Of carburetor adjustments made
by gas analysis in the bureaus exper-
iments, an actual increased efficiency
in mileage and saving of gasoline
amounting to - per cent was attained
In the following month. The tests
demonstrate that a portable carbon
dioAide indicator for testing the ca
haust gases OF a motor vehicle gives Il
positive indication of the carburetor
adjustment, removes all gucsswork of
adjustment, is perfectly feasible prac-
tically. and is almost indispensable to
company having ten or more large
trucks in service, especially If sup
piled with adjustable carburetors.
The Government Fuel Yard trucks
tested by the Bureau OF Mines ranged
in capacity from 21a to 7 " tons. Dur /
ing the winter months, when the de-
mand Tor coal is heavy, from 80 to
35 trucks are used. Samples of the g,
exhaust gas were taken on the trucks
kept In service for summer hauling in !,
order to determine the carburetor adj j
iustment as used. Changes were then ,
made to more economical adjust i
ment wherever possible, without sac /
rihcing fexibility of operation and
power, In every case the adjustments !,
were maintained for maximum pow
er, but were adjusted to The leanest
position to give that power. In all
but one case the carburetors were
found to be adjusted too rich for
maximum power and economy.
Increase Mileage % Per Cent.
The actual increase in mileage and
saving of gasoline due to the carbur-
etor adjustments made by gas anay-
sis, when the month previous and fol-
lowing the adjustments are compared, !
showed an increase in mileage Of %
per cent; for the second month after
adjustment Is per cent; and for the
mileage Is compared truck for truck,
and not taking into consideration the
distance each Travelled during the
month, the increased mileage equaled
FAT, 21.o and 1872 per cent, respec-
lively.
The adjustment of carburetors by
analysis of exhaust gas is based upon
the fact that the carbon dioxide in the
exhaust is a direct indication of the
air-fue ration and completeness of
combustion. In turn, the air-fuel ra-
ito and completeness of combustion S
tells whether the carburetor Is prop /
arly adjusted for maximum power and /
gasoline economy. . s
Other conditions being constant, the !
mileage obtainable varies as the per- {
1entage of carbon dioxide in the ex-
haust gas and air-fueI ratio. This has
been little realized by most garage
men In the past. The other factord :,
are carefully watched and guarded
against, while carburetor adjustment .
ss usually left to the mechanic or :.
driver who adjusts according to his
own notions Usually the adjustment a
Is far too rich for maximum economy.
There are, however, exceptions to this
rule. A determination of the carbon
dioxide content of the exhaust gas
while the vehicle is being operated on c
the road gives Il positive indication of /
the carburetor adjustment, and re- r
moves all guesswork. +
CarburctOrs Get 'RicI,.'
The results Of the Bureau of Mines
experiments show that adjustable car
buretors tend to become more richly
adjusted with lapse Of time, and that r
the adjustments should be checked at r
least every two months to maintain ,
the most economical adjustments If =
the monthly mileage is recorded, it ;
becomes only necessary to check the :,
adjustment of those that fall below
the usual mileage which should be OBJ
tanned when properly adjusted. The
carbon dioxide indicator used for {
making the adjustments while the |.
trucks were operated was found to be
practical and easily operated by the :
laymen inexperienced in the handling
of chemical apparatus.
The bureau suggests that one driv
err may be able to get considerable
more mileage than another, due to
the method of driving. The mileage '
Is greatly increased by disengaging t
the clutch whenever possible and Q