IMPROVEMENTS IN GAS MOTOR ENGINES
Year: 1874

page_text: PROVISIONAL SPECIFICATION left by Charles Denton Abel at the
Office of the Commissioners of Patents, with his Petition, on the
2nd February 1874.-A communication from abroad by Gottlieb
Wilhelm Daimler, of Muelheim on the Rhine, in the German
Empire, Civil Engineer.
I, CHARLES DENTON ABEL, of No. 20, Southampton Buildings,
Chancery Lane, in the County of Middlesex, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN GAS MOTOR ENGINES,"
to be as follows:-
This Invention relates to improvements in gas motor engines of the
kind described in the Specifications of Letters Patent granted to me on
the 12th February, 1866, No. 434, and on the 3rd August, 1867,.
No. 2245, being communications to me from E. Langen and N. A. Otto.
The engine described in the said Spec. operated in the following
manner: A piston was raised in a cylinder a little distance, drawing
in through the ports of a slide a charge of combustible gas and air at
atmospheric pressure, in suitable mixture for ignition. A flame being
then drawn in ignited, the gaseous mixture, which, by its expansion

page_text: propelled the piston along the cylinder. The cylinder being kept cool
by a water jacket the pressure of the products of combustion within
the cylinder was rapidly reduced, and the cylinder being open at top
the piston was propelled backwards by the superior pressure of the
external atmosphere, the products of combustion being finally expelled
by the piston as it approached the extreme of its in stroke. The piston
rod was toothed as a rack and geared with a wheel mounted on the
engine shaft, which was provided with a heavy fly wheel. The wheel
geared to the piston rod was mounted on the engine shaft with a clutch
in such manner that it could turn freely on the shaft in the one direction
when the piston was making its out stroke, but that when the piston was
making its in stroke the wheel caused the shaft to revolve with it. This
shaft or a shaft connected with it had on it cams or eccentrics for
moving the piston through a portion of its stroke out to draw in the
gaseous charge, and also for moving the slide so as to admit the gaseous
mixture and the igniting flame to the cylinder, and to permit the
products of combustion to escape therefrom.
In the improved engine to which the present Invention relates the
principle of action is substantially the same as that set forth above, but
the working of the piston and slide from the main shaft is effected in a
more simple and efficient manner than formerly.
The slide is arranged to operate upon a single passage for inlet to and
outlet from the cylinder, and the action of the engine is regulated by a
governor so as to economise expenditure of gas when the velocity of the
shaft is sufficient for the work of the engine. For this purpose a crank
is mounted loosely on the main shaft of the engine, having on it a spring
pawl. which can engage with the teeth of a ratchet wheel fixed on
the engine shaft, or be disengaged therefrom as will presently be
described.
When the pawl is engaged the crank revolves with the shaft, but
when the pawl is disengaged the crank remains at rest. From this
crank there are two rods, one connected to the slide which is worked
when the crank revolves with the shaft, and the other connected by a
slotted hole to a lever fixed on a rocking shaft which has two arms. One
of these arms is pressed upwards by a spring, and when it is so pressed
upwards it comes in the way of the pawl on the crank, and in disengaging
it from the ratchet wheel brings the crank to rest. The other arm

page_text: supports a forked rod presenting its fork to a pin projecting from the
piston rod. When the piston is down this pin resting in the fork of the
rod prevents it from rising, and thus prevents the pawl on the crank
from being disengaged. The crank in its revolution with the shaft while
it moves the slide moves also the rocking shaft and its arms, and the
last described arm with its forked rod being thus raised pushes up the
piston so as to draw into the cylinder the gaseous charge and the igniting
flame. The expansion caused by the combustion of the charge propels
the piston upwards, and the pin is thus raised out of the fork of the
rod, which is then free to rise in obedience to the spring, whereupon the
other arm of the rocking shaft is brought in the way of the pawl and
disengages it from the ratchet wheel. The crank now remains at rest
and the slide is stationary until the piston in its descent brings the pin
into the fork of the rod, whereby the arms of the rocking shaft are
pressed down, the pawl is set free and engages again with the ratchet
wheel, and the action is repeated. A governor driven by bevil gear
from the main shaft works a lever, one end of which when the governor
balls are expanded comes in the way of a projection on the spring pawl
and prevents it from engaging with the ratchet wheel. But when the
governor balls collapse the end of the lever is moved out of the way of
the pawl, which is then free to engage with the ratchet wheel as
described above. Thus when the engine shaft is revolving with a speed
so great as to prevent the pawl from engaging, the slide and piston
remain quiescent, and there is no expenditure of gas; but when the
speed of the shaft is so far reduced as to permit the pawl to engage, the
slide and piston are moved so as to charge the cylinder and ignite the
charge, and the return stroke of the piston gives additional motive power
to the revolving shaft.
The slide, worked as above described, is made with ports and passages,
and the slide face and cover are made with corresponding ports and
passages for the ingress of air and gas and of the igniting flame, and
for the egress of the products of combustion through one and the same
passage communicating with the cylinder. While the slide is moving
downwards and the piston is at the same time moving upwards, air and
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page_text: its ignition, the piston is propelled rapidly upwards, after which, as
the products of combustion contract, the piston descends, and as it
approaches the end of its downstroke, the slide is moved so as to present
a passage for the egress of the products of combustion.
The passage of egress may be controlled by an adjustable valve so as
its ignition, the piston is propelled rapidly upwards, after which, as
the products of combustion contract, the piston descends, and as it
approaches the end of its downstroke, the slide is moved so as to present
a passage for the egress of the products of combustion.
The passage of egress may be controlled by an adjustable valve so as
to moderate the descent of the piston during the last portion of its
stroke.