The Washington times., 1923-12-29
By Alexander Johnston,
Editor of Motor.
Copyright, 1923, by International
Eaature ShrVice Inc

greater progress in the development
of engine cooling than all the period
before. Engineers have learned
much about the possibilities of this
part of the car, and the ordinary
car owner will be the better for be-
ing informed on the subject
To begin with, the cooling system
is necessary evil. Thirty five per
cent of the power generated in the
cylinders is dissipated through the
cooling water. If 1T were not for the
fact that oil breaks down and burns
under high heat We could get along
without the cooling system and save
over third of the power that is now
wasted. However, fabrication is abb
solutely essential in the internal COM
bustion engine, and to maintain the
oil film between the various moving
parts we have to have the cooling
system.
At the present time there are two
distinct methods of cooling the en-
glne-one employing water, the other
air. In the air-cooled engine the
heat is dissipated through fins
projecting out from the cylinder. In
the water-cooled system the fluid is
kept in constant circulation in
Jackets or compartments around the
cylinders. The system includes a
radiator, fan and a means for keep
ing the water circulating.
In operation the water circulates
around the cylinders and then goes
to the top of the radiator and flows
| down to the bottom through the
tubes or cells, giving off its heat
on the way. The fan draws air
through the interstaces between
| the tubes or cells and this air
carries the heat away from the
water. Without the fan, d much
greater area would be necessary
than could be obtained in the
radiator of a car
| Two methods of forcing the cir.
culation Of water through the sys-
tenn are now in vogue, therrno-
syphon and pump. Thermo syphon
cooling is sometimes called the
natural method. No pump is used
here, the movement of the water
being assured through the natural
law that hot water is lighter than
cold and consequently rises to the
top. In this system, as soon as the
engine starts, the water in the
jackets gets hot, rising to the top,
I displacing cooler water. In this
way the hot water pushing its way
| to the top and the cooler water
rushing it to take its place. starts q
| circulation of the fluid, sufficient to
keep the engine properly cooler. IT
is necessary in the thermosyphOn
| system that the water pipes be of
generous size and that the radiator
be placed high above the water
Jackets, so that the outlet pipe will
slant upward, while the inlet pipe
will show little slant.
The thermo-syphon system Is the
simpler method of cooling the en-
CINE and, when properly designed
is effective for ordinary service. 1t
has not the positive action of the
pump system, but it does very well,
! particularly on V-type and horizontal
| engines, where the radiator may be
set high as compared with the water
| Jackets. This system works very
well in small engines.
In the pump system a centrifugal
pump driven by the engine forces
the water through the system and
| maintains a constant and positive
circulation. So long as the engine
is running the pump must force a
flow of water through the cooling
system. The pump system is more
| expensive than the thermo-syphon
The radiator member of the cool.
! ing unit, has a tank at the top and
another at the bottom. The core is
| the section lying between the two
tanks, which looks like honeycomb
There are two different types of
radiator cores. tubular and cellular
In the tubular type the water passes
through the tubes and the air is
drawn through the spaces between
the tubes. In the cellular type the
air is drawn through the tubes and
the water enters the tank at the ton
OF the radiator, where it is baffled
so that instead Of flowing down one
| SIDE of the core, it is distributed all
over the cooling area. In the lower
tank there Is provided a means for
receiving the water from all parts
of the core.
rev car owners realize that the
shape Of the radiator has ANYTHING
TO do with the efficiency of the
cooling system. 1t has, however,
the nigh, narrow radiator, such as
| IS used on racing cars, gives the
water a greater distance to travel
downward through the core and
consequently more time to get rid
or Its heat, and all water is ex.
posed to the fan draught. It used
10 happen often that too small a
radiator was fitted in the ordinary
car, so that overheating troubles
developed, but in present day cars
| the radiators are generally entirely
efficient for the work they have
! to do.
| Now, while II Is necessary to cool
the engine, AS we explained in the
FIRST place, it is not good TO cool it
too much. There Is a certain point
! OF ma ximum efficiency and within
the past two years engineers have
| oeen learning much as to the best
method or maintaining the engines
temperature at just this point
The principal means Of attaining
this end Is thermostatic control of
the waters temperature. This con
troll means the fitting In the wator
line OF a device which shuts off
the flow OF water until a certain
temperature IL reached, when II
permits the circulation to proceed
until the water Ia cooled enough
when the flow Is again interrunted
A variation Of tAis is found in the