Los Angeles herald., 1910-06-12

ter through its water circulation.
The total amount of heat taken up
by the cylinder walls depends-other
things being equal-on the time the hot
gases are In contact with these walls,
the shorter the time the less heat abb
sorbed. OF two cylinders, one having
ports cut all around at the base so that
they can be uncovered by the piston,
instantly, at the end of the power
stroke, allowing all the hot exhaust
gases to escape at once, and the other
with q poppet valve controlled port In
the cylinder head, through which the
piston had to drive these exhaust gases,
the last will heat up vastly more than
the first, just as an iron will get much
hotter If kept in the fire for two min
utes than II for only one.
This demonstrates the necessity of a
free exhaust, the quicker the exhaust
can be gotten out of cylinder the bet
ter the results.
If, say, one square inch Of any metal
having a temperature greater than that
of air be exposed to the air, 1t will
radiate q given amount of heat each
second until 1t has been reduced to the
same temperature as the air. All gas
engine cooling depends on this prin-
ciple.
If a cylinder should be made smooth
not be sufficient to give the required
radiation to the atmosphere, therefore
one type of motor is provided with a
water Jacket l nthis case the heat Is
taken up by the water and carried to
the radiator. and the sole function of
this radiator is to provide the necessary
surface so that the heat can get to the
air. In the air cooled engine this extra
surface is secured by flanges or pins.
20 hn ntJta in
der wall.
In the early days Of the automobile
there was hardly an engine, either air
or water cooled, which would not over
heat If required to give its maximum
power for any length OF time. Neither
the designer nor the driver understood
the gas engine as they do now, and the
results were bad when compared with
those secured at the present time.
PISTON FORCES EXHAUST
The designer made his exhaust valves
very small, and with a short lift, max
ing an opening through which the eX-
haust gas couldn't possibly pass until
actually forced out by the piston. The
average driver believed that if little
gasoline was a good thing, more was
better, and adjusted his carburetor so
that it gave the engine all the gasoline
1t could possibly handle and still run.
These two things, the choked exhaust
and the excess of gasoline, are the most
potent agents one could devise to pro-
duce a hot cylinder.
Things are different now. The IVA
ter cooler gives his valves the maxi
mum area and lift as high as good
mechanics will allow, while the "air
cooled" man goes him one better. The
driver has also learned that there Is a
quantity of gasoline which produces q
normal mixture, and that this mixture
gives him the greatest power, any ex-
ira gasoline not only being a waste but
decreases the work that his engine will
do, and these are the only secrets of a
successful air cooled motor.
The air cooled engine is the ideal en-
g1ne If properly designed. 1t saves
many pounds in weight, requires no ra-
diator, water Jacket, pump or piping,
and costs much less than a water
cooled motor to build. 1t saves the
trouble and annoyance of leaky radi-
ators, pumps that "go out of commits
sion." non-freezing solutions etc, and
running with the cylinder walls at the
proper temperature, gives the maxi
mum mileage per gallon of gasoline.