Los Angeles herald., 1909-12-19


high speed gas engines, such as are
used in automobiles, both pleasure and
business vehicles, cannot be over
estimated, and the underlying prin-
ciples that govern the general action of
good fabrication and also the specific
physical conditions that exist in cylin-
ders of the engine must be given due
attention.
From the study of the general prin-
ciples of fabrication it is seen that
series of results has to be accomplished.
The friction of the moving parts must
be reduced to a minimum, the surfaces
of the moving parts must be kept free
from any gritty matter that would have
an abrasive action, and, in the cylin-
ders, the lubricant must act as an eff
fective seal between areas of higher
and lower pressures. To maintain this
action and accomplish these results the
oil used must be of the finest possible
quality, free from acidity that would
pit the metal surfaces, free from any
inclination to be "gummy" and stick
when partially evaported, and also free
from a tendency to leave any solid de-
posit when completely evaporated.
Before the subject of fabrication had
been as fully studied as II is now 1t
was thought that an oil of high vis-
costly gave better fabrication than an
oil of low viscosity, irrespective of the
work it had to do.
Viscosity Should Vary with the Work
In regard to viscosity, which is the
relation between adhesion and cohesion
of an oil, the most suitable oil under
all circumstances is the thinnest oil
that Will stay in place and do the work.
For some work an oil of higher Wis
costly is needed than for other classes
of work, but this rule governs all cases,
and the work to be done determines the
most suitable viscosity of the oil to be
used.
These are the general principles of
fabrication, and 1t is now necessary To
study the specific physical conditions
that exist in a gas engine cylinder and
adjust the general principles to the
conditions.
In a gas engine cylinder there is a
combination of conditions that produces
at the same time high temperatures.
high pressure and frequent elections
of gaseous matter from the cylinders
through the exhaust valves. The oil
used to lubricate gas engine cylinders
must therefore be able to withstand
high temperature, to remain an oil for
sufficient length of time to lubricate
thoroughly the walls of the cylinder
and act as a perfect seal. and should
also, when finally evaporated, pass ont
with the exhaust and leave no SOLID
deposit
The usual type of gas engine used
for automobiles on the market at pres
ent is the "four-cylinder" type. There
are a few "two-cylinder" engines, but
the use of this type is not at all gen
eral. In the cylinder" type there
are four distinct strokes of the piston
to every explosion of gas The cyl nder
sucks in a charge of Vaporized gaso-
line mixed with air on the first stroke
congresses the charge of the gasoline
on the second stroke, explodes and ex-
pands the charge on the third stroke,
the real motive stroke, and on the re-
turn, or fourth stroke, exhausts the
spent charge through the exhaust
valves, and is then ready to take
in a new charge. The action Is
then repeated as long as the engine
is in operation This action in the
cylinder produces high temperatures,
and also violent fluctuations of pres
sure, during which all the gaseous con-
tents is elected through the exhaust
valves. 1t will be seen, therefore, that
the oil must be able to stand these con-
ditions and do it's work of fabrication
during the entire period of each cylin-
der.
Types Of oil lnjectors
There are many forms of oil inject
ors in use on the market today, but the
most important types are of the
"splash" system and the force feed"
Variation in type only means variation
in the method of applying the lubri-
cant to the surfaces to be fabricated,
and though it is a most important point
TO have efficient distribution, yet the
high lubricating value of the oil in
troduced is of greater inheritance, be-