Los Angeles herald., 1910-10-16
STARTING MOTOR ON SPARK
SUBJECT TO 8 CONDITIONS
Character of the Mixture in the
Cylinder Most important

Three conditions are necessary for
motor to start on the spark. First,
the motor crank shaft must come to
rest in such a position that enough
of the energy OF combustion can be
applied to it to bring the next piston
over it's compression center. Second,
the cylinder should contain q mixture
capable of imparting enough energy
to bring the next piston over the COM
preston. And, third, the ignition
mechanism should be capable of firing
the mixture in the proper cylinder,
provided 1t be in position that will
insure starting if other conditions are
favorable.
Now, as to the matter of the posi-
tion in which a motor should come to
rest, it may be said that, barring the
possibility of stopping on centers, the
crank is almost certain to come to
rest in that position where the pres
sure in the cylinders which are on the
working and compression strokes, re-
spectively, are equal. This will prob
ably be with the working piston a little
above the center of it's travel. This
can be shown in various ways Watch
the fywheel of a motor when it is
coming to rest, and it will be seen
that, just before finally stopping it
will oscillate back and forth q few
times. If, the compression cocks are
opened Just before this the oscillation
will not take place. Another thing
which shows that the crank shaft
normally will come to rest in one posi-
tion is that, upon engaging the start
ing crank, the position at which it
takes hold will always be almost
identically the same. Any position from
center to quarter is at least favorable
for starting on the spark. The chances
of a four-cylinder motor which is in
good condition stopping in this posi-
tion are certainly better than ten to
one. If one of the cylinders, either the
one on the compression stroke or the
one ON the working stroke, is very
much lighter than the other its piston
will tend to stop much nearer the
lower center. For this reason a leally
cylinder will tend to cause the motor
to stop in an unfavorable position for
spark starting. Therefore, 1t may be
laid down that in order to insure the
greatest chance of a motor stopping
in 81 good position for starting, the
valves and piston rings of all cylin-
ders should be uniformly tight.
All things considered, the most i'm
portant condition for starting on the
spark is the character of the mixture
in the cylinder. In the first place, in
practice, the mixture is generally not
far from atmospheric pressure at the
time of starting, since no cylinder can
hold either a vacuum or a pressure
above atmospheric for any great length
of time. 1t is no uncommon thing for
cylinders and pistons to have differ
ence in diameter upward of 1872 of an
inch. Then, also, the ends of the pis-
ton rings never quite meet, so there
is a clear but tortuous passage left for
the escape of the cylinder charge.
However, it can be easily proved that
compression is not necessary for start
ing on the spark.
L. J. Ollier, manager of the EMF
branch in Los Angeles, was allotted
1850 EMF "30' and Flanders '20"
cars for his subagencies in 1911. He
rnnnr.t ed saNaraI DAYS ago hv wire that