The Devils Lake world and inter-ocean. (Devils Lake, N.D.) 1915-1920, 1915-04-01
Read What Chief Engineer Mar says about the "valve in the Head
Motor" He draws the largest pay check Of any engineer in the
world and knows what's what.

two rooms, leaving no inlet or outlet to the
hallway except the two windows at the head
Of the hall. These windows serve as the
valves in a valve-in-head motor. That's
What the term means-the valves are in
the head of the motor, just as the two
windows are at the head Of the hall. Sure
ly you can see how much easier it is to get
air into and out Of that hall through these
windows than through the windows at the
far sides of the adjacent rooms.
Nov for the application of these prin-
ciples. Now We will see exactly why the
valve-in-head motor yields more power for
the same amount of fuel.
Il told you, you remember, that the first
step in the production of power in an auto
mobile engine is the introduction Of vapcr-
lied gasoline, or gas, as we call it, into the
upper end of the cylinder. This gas is in
troduced through the intake valve. Once
into the cylinder, the piston head, returning
under momentum from its previous down
ward strokes, squeezes, or congresses this
gas. And just at the instant of highest
compression the electric spark explodes il.
10 explode gas means to heat it, and heated
81 SNP~AiNc ~ ii CIlIS cApdl-
sion of the gas that forces the piston down,
thus turning the crankshaft.
"Now let's return, for a second, to the
instant Of the explosion. The gas has been
introduced into the upper end of the cylin-
der, through the inlet valve, and the piston
III Its upward thrust, has compressed that
gas into a very small space. The electric
spark plug to the other terminal, an eighth
of an inch away. What happens? Why,
the compressed gas is set on fire. and YOU
Know what happens when gas is set cn fire.
1T expands. 1t expands violently. Il tries
TO get out of the cylinder. 1t pushes and
Struggles in every direction, and from every
direction, save one, it is hurled back. The
one portion of the surrounding surface
Which yields under its onslaught is the pis-
ton head. The latter, unable to Withstand
the attack, is pressed downward. The piston
is attached to the cranks1aft and when the
pison presses downward the crankshaft
turns. This causes the drive shaft 10 re-
volve, and when the drive shaft revoives tho
rear axle turns. Attached to the rear axle
are the wheels, and when the axle turns
they turn too. Thus the automobile moves.
Now it happens that the man up in the
seat, who has to pay for the gasoline, wants
That gasoline to go as far as possible. He
wants the last ounce of power that be can
get. He wants the full force of that cx-
ploslon to be hurled against the ton o. lie
piston head.
This brings us to the Il and IT head.
and to the valve-in-head construction again.
In the first two types, when the EXPLOSION
takes place, the lines of force are scattered.
Some of them go downward against the MS
ton, where they should go, ard Others arc
hurled sideways into the valve chambers.
where they do no good.
In the valve-in-head motor there are no
valve chambers, OF pockets. Ever last
ounce of the force generated in the explo-
sion goes directly against the piston head.
There is no place for this force to go. Let's
return to our hotel hallway illustration &
gam. Suppose you We're standing about
halfway down the hall, at a place that
would correspond to the location Of the pis-
ton head in the cylinder. A revolver is fired
IN the room to the left, corresponding to the
valve pocket in an r. or IT. head motor.
Why, you hardly hear it, let alone feel anv
conclusion But suppose the doors leading
10 those rooms were closed and the same re
volver fired in the hallway just in front of
you. Can't you imagine the difference?
Your ear drumsw would rock and you would
distinctly feel the conclusion of the air. In
a word, the full force of the explosion would
be directly toward you, just as it is directly
toward the piston head in a valve-ip-head
motor.
Nov we come to the very important mat
ter of getting the dead gases out of the top
OF the cylinder after the explosion. After
each explosion in the cylinder there is a
residue of dead gases. The inside Of the
cylinder walls, you know, must be constant
~ fabricated, so the piston will work I'D and
down with the least possible friction. Some
Of this !ubricating oil is burned with each
explosion, and this leaves a residue Of car
bon in the cylinder.
1t is the duty of the piston head, in the
upward stroke following the explosion, to
push all these n-ar gases, j.. uding The ca.-
ben ,out OF ''c r.iinlet II they are -.