Devils Lake inter-ocean. (Devils Lake, N.D.) 1909-1915, 1911-12-01
FUEL FOR AN ENGINE
Other Things to Consider Than
Starting and Stopping.
Few People Realize Importance Of Sup
plying Air and Gasoline in a Def
mite Proportion carbureter
Does the Mixing.

! iBy c. L. GUINNESS Professor of Ensi-
neertng. North Dakota Agricultural
Colege.)
When a man buys a gasoline engine
the first problem that confronts him
is how to start and stop it These
things are usually learned in a very
short time through the assistance of
the expert who delivers the engine or
the small book of instruction found in
the tool box. The gasoline engine op-
orator should, however, not be salts
fed with his engineering if it covers
only these two points, starting and
stopping. He should have in mind to
so operate his engine that 1t would
show the least possible wear and that
It would give the maximum power for
the minimum amount of fuel con-
sumed
The relative Importance of these
two items will depend somewhat upon,
circumstances, but in all cases the OPP
orator must bear in mind that the cost
of the power produced is made up of
the wear and tear of the engine and
the fuel used plus fixed charges of
wages, interest on Investment. ETC.
In this article we will consider only
the influence of the proper mixture OF
air and gasoline upon the amount of
fuel used.
Few people realize the importance
of supplying air and gasoline in a def
4 mite proportion to the gasoline engine.
! We ordinarily think of a gasoline en-
CINE as using gasoline as fuel, not con-
sidering the air, but the latter is quite
as essential as the former. A mix
ture Of gasoline vapor and air will
explode or burn if the two are present
in the proper proportion; but a mix
ture too rich in gasoline will not ex-
, plode nor will one which is very weak
or lean. The function of the carbur-
ter, or mixer, on the engine is to mix
the air and gasoline in the proper pro-
portion; but every carburter is ad-
Unstable, and it becomes the duty of
the operator to adjust the amount of
gasoline that the carburter feeds the
engine, the air remaining constant as
a rule.
1t takes but small amount of ex-
perfmenting on the part of the opera
tor to discover that a very rich mix
ture of very lean one will not ex-
plode and that the engine will stop If
supplied with very large air or
very small amount of gasoline We
must not imagine, however. that be-
cause an engine keeps on running that
it is getting the proper mixture.
There is quite a range from the rich
est to the leanest mkt ure that an en-
CINE will run at. and the operator
must find the point at which he will
get the maximum power for the
amount of fuel used
AS means of detecting whether our
mixture Is very rich or weak, we find
that black smoke at the exhaust is
, caused by too much gasoline and that
sharp explosions in the exhaust pipe
by very lean or weak mixture. We
also find that the lean mixture will
cause the engine to miss explosions
even though 1t may keep on running.
1t is impossible to give a very def
mite suggestion as to the amount of
gasoline to supply, but we find that
the average engine will develop its
greatest power when the gasoline sup
ply is just a trife less than that
which will cause black smoke at the
exhaust. The most economical mix
ture is. however. not quite as rich as
the one which will give the maximum
power. and hence we find that most
engines will run more economically
at load little less than their max
imum
/ This question of running the engine
economically may or may not be an
important one, and this will usually
depend upon the size OF the engine.
AS tar as the cost of fuel Is coz
cerned, 1t matters little whether a
one-horse power pumping engine is
run with rich or lean mixture, in
asmuch as tho cost of the gasoline
used Is small in any event, but with
large blowing engine it becomes an
entirely different matter When an
engine uses from so to Is gallons of
gasoline day saving of small per
cent OF this amount will materially
> aHect the cost Of the days run. We
, also lind that the engine will give less
trouble and require less attention If
supplied with the proper mixture of
air and gasoline