Gas Motor with Differential Cylinders.
Year: 1897

page_text: Date of Application, 12th June, 1897-Accepted, 8th Jan., 1898
Gas Motor with Differential Cylinders.
I, GEORGE GREGORY SMITH of St. Albans, Franklin, Vermont, U.S.A., Lawyer,
de hereby declare the nature of my said invention and in what manner the same
is to be performed, to be particularly described and ascertained in and by the
following statement:
The object of the present invention is to construct a gas motor in which an
effective stroke is given to the piston at each revolution of the shaft, thus avoiding
the cycle system and flywheel entirely. At the same time according to the present
invention the explosion chamber behind the piston, which occupies about a third
of the capacity of the cylinder in the Otto cycle system is avoided and the products
ef combustion are entirely removed from the cylinder after the explosion has taken
place. The disadvantageous effect caused by the presence of about a third of the
products of combustion in the cylinder at the same time as the fresh explosive
mixture is introduced into the cylinders is well known,-in the cycle motors
about 33% of the products remain in the cylinder and mix with the fresh gas or
mixture deteriorating very considerably its capability of explosion or explosive
power.
The present invention may be applied to one-cylinder-motors if a flywheel is
employed, but the motor is more particularly constructed for a multiple-cylinder-
machine, in which case the flywheel may be dispensed with and the machine will
also be reversible, which is not possible with the cycle motors.
Thus for instance, if two cylinders are employed in a machine embodying the
present invention, the motor may be reversed by reversing the order of the
explosions in the cylinders, whilst at the same time a multiple, and particularly
a three cylinder engine will run evenly without a flywheel and is reversible, so
that the same could be employed for motor cars and for marine engines.
In order to render possible the omission of the explosion chamber in the working
cylinder, a chamber has to be provided which is in connection with the cylinder
and which may be cut off from the cylinder after each explosion has taken place
7.e. the explosion chamber would have to be partially or entirely divided off from
the cylinder during the backward stroke of the piston or whilst the products of
combustion are being expelled and furthermore, the feed of the explosive gas or
gas mixture would have to be cut off from the explosion chamber until the
products of combustion have been removed therefrom.
Now, in order to attain these results, two conditions, must be necessarily ful-
filled; first, the explosive mixture must be fed to the cylinder under the pressure
necessary to effect the explosion and secondly, the feed must only take place at a
certain predetermined moment i.e. at the moment before the explosion is to take
place. It is, however, not advisable nor in some cases even possible to store a
considerable quantity of explosive mixture at the necessary pressure on account of
the danger this would involve and in order to avoid this disadvantage, according
to the present invention, the air and gas are conducted separately to a mixing

page_text: valve arranged in proximity to the explosion chamber and are thus mixed on
entering the chamber.
After many experiments the arrangement of a differential cylinder appeared to
offer the best means of effecting the desired results and fulfilling the necessary
conditions. In accordance with this idea a smaller cylinder is arranged behind
the working cylinder, said smaller cylinder serving as explosion chamber and
having a piston as hereinafter described. The two cylinders are divided or
separated by a slide whilst the explosive mixture is being fed to the explosion
chamber, the said slide being suddenly opened the moment before the explosion
takes place, and being gradually closed immediately after the explosion has taken
place.
131-
In order to more clearly explain the nature of the present invention, one form
of embodying the same is diagrammatically illustrated in the accompanying
drawings, but it should be clearly understood that the invention is in no way
limited to the number of cylinders nor are the details of construction shown and
described to be considered as essentials, since evidently the same results could be
obtained in a variety of ways, without departing from the spirit of the present
invention.
On the drawings:-
Fig. 1 is a longitudinal section through the middle cylinder,
Fig. 2 a plan and
Fig. 3 a cross section on the line of figure 2 of a three cylinder motor
involving the principles of the present invention.
In the case illustrated, three cylinders 1, 2, 3 are proposed, each having an
explosion chamber or differential cylinder 1", 1, 1° attached to the rear cover of
the cylinder. Both cylinders may be separated by means of a slide 22 which is
suddenly opened the moment before the explosion is to take place. Both cylinders
are provided with pistons 36 and 44 respectively. The piston 36 of the working
cylinders 1, 2, 3 is connected by means of a connecting rod 11, 12, 13 with a
driving shaft 4, the several cranks being arranged at angles of 120° apart. The
shaft 4 is connected by bevel gearing 67 or other suitable means to a shaft 5
situated at right angles to the same, and bevel gearing S, 9 connects this shaft
again to a further shaft 10, which is advantageously arranged parallel to the main
driving shaft and serves to work the pistons of the smaller cylinders by means of
sliding blocks or other suitable means. At right angles to the shaft 5 is another
shaft 27 (Fig. 3) which is driven from the shaft 5 by bevel gearing or the
like 28, 29 and serves to drive a shaft 26 by means of bevels 30, 31, svid shaft being
This lower shaft is provided
mounted in the lower part of the machine frame.
with cams 25 on which the rods 23 of the slides 22 run, being provided with rolls
for the purpose and depressed on to the cam by means of a spring 24. The cams
are so shaped as to let the rods and with them the slides fall the moment before
the explosion takes place, thus establishing communication between the two
cylinders.
The motor is further provided with an air pump 18 which keeps the air stored
at the desired pressure in the reservoir 19 and is driven from the main driving
shaft. A gas reservoir 20 is also provided, which is fed by a gas pump 17 and
contains gas at the requisite pressure. The gas and air under pressure may be
fed to the cylinder or explosion chamber 1, 1, 1º in a variety of ways, in the
present case for the sake of simplicity a valve 32 is proposed which works in a
chest 32 As may be seen from figure 2, the casing has two inlet openings to the
valve, of which one is connected to the gas reservoir by means of a pipe 35 whilst
In the walls of
the other communicates through a pipe 21 with the air reservoir.
the explosion chamber a valve seating is provided, having two ports corresponding
to those of the valve, these ports merge into one at 32b and lead into the rear end
of the explosion chamber. The slide valve is provided with a valve rod 33 and
driven by means of an eccentric 34 on the shaft 26.
The piston of the working cylinder is provided with a boring, which is closed

page_text: by a valve 37 when the piston advances. When the piston has reached its extrenie
forward position, the end of the valve rod 38 strikes a stop 39 which causes the
valve to open. By suitable catch mechanism the valve is retained open during
the back stroke of the piston when the catch is disengaged by a stop 40 at the
bottom or cover of the cylinder and the valve closes by means of a spring at the
moment before the next explosion takes place. The products of combustion are
thus blown out through the piston, but it should be understood that an outiet for
the same might, if desired be arranged in the cylinder walls, such outlet being
closed by a suitable valve, in the present case however it seems advantageous to
arrange the valve in the piston.
... I'
.1
A similar arrangement could be made in the piston of the explosion chamber,
but such appears as at present advised unnecessary, since the products of explosion
contained in this chamber, will be driven through the outlet of the working
cylinder, if the slide between the two is closed slowly.
run.
Both pistons .e. that of the working cylinder and that of the differential
cylinder do not run at the same angle the former being set at about 30 degrees in
front or ahead of the latter, so that when the working piston has reached its
extreme back position, the explosion chamber piston will have about 30 degrees to
This is a most important feature of the present invention, and the object of
this arrangement is to utilize the full power of the explosion to drive both pistons
in the effective direction and thus to attain an effecive working power which will
be slightly in excess of the actual calculated differential power of the machine.
Thus as will be readily understood when the explosion takes place, it will act to
drive the working piston forward and will also drive the piston 44 the last end of
its stroke.
The motor operates in the following manner:-
At this
If the working piston is in the position shown at figure 1, the piston of the
explosion chamber will have about 30 degrees of its stroke to finish.
moment the mixing valve has just been opened and the cylinder 1b filled with
explosive mixture. Immediately after this the slide is again closed and the
slide 22 falls, allowing both the cylinders to communicate. At the same moment
the ignition takes place and the piston 36 is driven forward, the smaller piston
being driven forward to the last 30 degrees of its stroke, after which it is drawn
back by the working piston and the shaft connections previously described.
When the working cylinder has reached its forward position, the piston valve 37
is opened by the stop 39 and is held open during the back stroke of the piston,
when it is closed by the stop 40. The products of explosion in the working
cylinder will be blown out through the piston valve and if the slide 22 is allowed
to close gradually the products in the explosion cylinder will also escape through
the piston valve of the working cylinder. It should be observed that the siide
must be properly closed as soon as the piston 44 has reached its extreme backward
position or rather an instant before this takes place so as to allow time for the
opening of the gas and air valve to feed the requisite charge to the small cylinder.
As soon as this has taken place the slide falls and the next explosion takes place,
the operations being repeated as above described.
No igniting device has been described in connection with the present specifica-
tion, because the nature of the same is entirely indifferent. The igniting.device
may be very simply actuated by a contact disc from the main driving shaft and
suitable electric connections or by any other suitable device, the operation being
very simple on account of the fact that the ignition takes place at each revolution
of the shaft.
.
The present invention is in no way restricted to the means described for
attaining the desired results since all of those could be varied in a number of ways
and equivalents substituted.
The machine can be easily reversed and in order to accomplish this, it is only
necessary to reverse the order of the explosions in the three cylinders. Thus for
instance if the first explosion takes place in cylinder 1, when the engine is running

page_text: forward, it would only be necessary to stop the engine, turn the shaft back half
a revolution by means of any convenient mechanical contrivance operated by a
lever and thus place the pistons in such a position as to cause the first explosion
to take place in cylinder 3, in order to reverse the engine.
It will be readily understood that the slide operating to separate the cylinders
could be actuated pneumatically if desired, the arrangement for such operation
being very simple.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:
1. In a gas motor, the combination of a working cylinder having piston, and an
explosion chamber having piston and arranged end to end with the working
cylinder a partition to divide said cylinder and chamber and means for removing
the same before each explosion, means for feeding the explosive mixture under
pressure to the explosion chamber shortly before each forward stroke of the
working piston, means for exhausting the gases of combustion, entirely both from
the working cylinder and from the explosion chamber, a driving shaft in con-
nection with the working cylinder and a driving shaft for the piston of the
explosion chamber and means for gearing the two said shafts and means for
igniting the explosive mixture in the manner and for the purpose substantially
as described.
2. The combination of a working cylinder and an explosion chamber cach
having piston as specified, driving shafts in connection with the piston of the
working cylinder and with that of the explosion chamber, and means for gearing
up the two shafts as specified, a valve in connection with the explosion chamber
and means for operating the same to admit the explosive mixture to the chamber,
at suitable pressure, a partition slide between the cylinder and chamber and means
for opening the same suddenly before each explosion, means for exhausting the
gases of combustion from both cylinder and chamber and means for igniting the
explosive mixture in the chamber at each stroke of the working piston, sub-
stantially as described.
3. The combination of a working cylinder and an explosion chamber arranged
end to end therewith, a piston to each cylinder and means for connecting each
piston to its respective driving shaft, driving shafts mounted as specified and gear
together, a valve in connection with the explosion chamber and means for feeding
explosive mixture under pressure thereto, means for operating said valve to admit
the mixture to the chamber at each stroke of the working piston, a slide to divide
the cylinder and chamber and means for opening the same suddenly before each
explosion and for closing it gradually after each explosion means in connection
with the working piston to allow of the escape of the gases of combustion both from
the cylinder and also from the chamber whilst the partition slide is gradually
closing and means for igniting the explosive mixture in the chamber as soon as
the slide falls substantially as described.
4. The combination of a cylinder and an explosion chamber arranged end to
end, a partition slide between the same and means for operating it as specified, a
piston to the cylinder and driving shaft in operative connection therewith, and a
piston to the explosion and driving shaft connected therewith, gearing to gear the
driving shaft and the explosion chamber driving shaft so that when the working
piston has completed its backward stroke, the chamber piston shall not quite have
completed its forward stroke, a valve to admit explosive mixture under pressure
to the explosive chamber as specified, means for igniting the mixture when the
partition slide is open and means for exhausting the gases of combustion both from
the chamber and cylinder substantially as described.
5. The combination of three-working-cylinders, having arranged end to end
therewith each an explosion chamber, pistons in the working cylinders arranged at
equal angles apart, explosion chamber pistons each arranged slightly in advance

page_text: of its respective working piston, driving shaft operatively connected to the working
pistons and a driving shaft operatively connected to the chamber pistons, valves
in connection with the chambers and means for operating the same to admit
explosive mixture under pressure to the chambers, partition slides between each
cylinder and its explosion chamber and means for exhausting the gases of com-
bustion from the cylinders and chambers and means for igniting the mixture in
the chambers at each stroke of each piston, substantially as described.
6. The combination of three cylinders having pistons as specified and driving
saft operated thereby, a rearwardly extending explosion chamber to each working
cylinder, a partition slide between same and the cylinder, means for operating the
said slide in the manner specified, a valve to admit explosive mixture under
pressure to the chambers, a reservoir to contain gas under pressure and a reservoir
to contain air under pressure, an air pump in connection with the latter and means
for driving the same from one of the machine shafts, a gas pump to keep the gas
reservoir charged and means for driving the same, pipe connections from each
reservoir to the valve of the combustion chamber, means for igniting the mixture
the chambers at each stroke of each piston and means for exhausting the gases
of combustion from the chamber and cylinder, substantially as described and for
the purpose specified.
"
CASTLE SMITH,
Invention" Office, Mitre Court, Fleet Street, London, E.C.,
Agent for the Applicant.