Improvements in Explosion Engines.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in Explosion Engines.
WALTER ROWBOTHAM, 24, Harleyford Road, Vauxhall, London, S.E., in the
County of Surrey, Electrical Engineer, do hereby declare the nature of this
invention to be as follows:-
I carry out
my improvements, the objects of which are to minimise vibration,
decrease the size & weight of the engine per H.P. & to reduce the number of work-
ing parts, as follows. I employ two pistons one working inside of & in an opposite
direction to the other which works in a cylinder connected to the frame of the
engine. This cylinder has a butt end & vibrating valve & is so constructed as to
contain more air or air & gas than the quantity contained between the two pistons,
so that when an impulse takes place & the pistons are driven out, the air or
air & gas in the cylinder is considerably compressed. The pistons in the course of
their action uncover two sets of port holes. Through one of these sets the com-
pressed air or air & gas out of the cylinder rushes in, effectually clearing out the
exhausted gases & driving them through the other port holes into the exhaust pipe.
In this way I get an impulse each revolution. The pistons are coupled direct by
connecting rods to the crank shaft, the inner piston to one crank on it & the outer one
to two cranks in such a way that at one time the one crank is inner & the two
outer & vice versa. I preferably use two fly wheels. The hydrocarbon or gas can be
either taken in by a force pump in between the two pistons or admitted at the butt
end of the cylinder. When I use a hydrocarbon I vapourise in accordance with my
Patent 22793/95 or 15279/96 &, as I prefer using the surface oil from the supply
tank, I fit the supply pipe at the bottom of & inside the tank with a joint. I then
continue the pipe to the inside top of the tank & there fit it with an air ball
weighted in such a way as to keep the mouth of the pipe just about the surface
of the oil. ignite either by electricity or in any other known suitable way.
When I wish to balance the motion of the fly-wheels I divide the crank shaft at
the centre crank & connect it by another connecting rod to the inner piston. I then
gear the fly wheels together to run in opposite directions. I sometimes construct
my engine on what is known as the Otto cycle. I do not then put a butt end on the
cylinder & I work the usual valves from a half speed shaft or half speed cam.
Dated this 20th day of November 1897.
5
I, WALTER ROW BOTHAM, of 24, Harleyford Road, Vauxhall, London, S.W.,
Engineer, do hereby declare the nature of this invention and in what manner the
[Price 8d.]

page_text: same is to be performed, to be particularly described and ascertained in and by the
following statement:
This invention relates to that class of motor in which the impulses are provided
by the explosion of a mixture of gas and air or oil vapour and air. The object of
the invention is to provide a motor of novel form having the several advantages of
reduced vibration, decrease in the size and weight of the motor per horse-power,
and a general simplicity of parts.
The invention consists generally in arranging two pistons so that one works
inside of and in an opposite direction to the other while between them an explosion
takes place every revolution and the outer piston works in a cylinder attached to
the frame-work of the engine. The pistons are coupled by suitable connecting
rods to cranks relatively placed at about an angle of 180° on one shaft or two
oppositely rotating shafts geared together. The working and compression strokes
take place between the pistons alternately while between the outer piston and the
cylinder a proportionate space is left to act as an intermediate reservoir for gas
and air and through suitable valves or ports alternately replenish its contents or
send a fresh charge to replace the spent mixtures between the pistons when the
working stroke is completed, the exhaust being displaced through suitable ports
or passages.
The accompanying sheets of drawings illustrate several modifications of the
invention and as follows:
Figure 1 is a vertical section through an improved motor with three cranks on
one crank shaft.
Figure 2 is another vertical section of the same motor on line a Figure 1.
Figure 3 is a diagrammatic view of a motor with three cranks on one crank shaft
but modified ports and passages.
Figures 4, 5, and 6 are corresponding diagrammatic views of a motor specially
arranged for balancing with two oppositely rotating shafts geared together.
One mode of carrying the invention into effect is illustrated at Figures 1 and 2
of the drawings and as applied to a motor with an overhead cylinder. A motor
shaft A running in suitable bearings is arranged with a central crank B having on
either side of, and at an angle of 180° thereto the two cranks D D. The central
crank B operates by its connecting rod E the interior piston F and the two
cranks operate by their connecting rods G G the exterior piston H. The
combustion chamber I is formed between the inner ends of the pistons and the
exterior piston works in an overhead cylinder J constructed with an extension or
reservoir K of a capacity exceeding the maximum displacement between the
pistons. Exhaust ports L are provided in the exterior piston H and corresponding
ports L in the cylinder J, and when the pistons are at their maximum distance
apart these ports coincide. A tube igniter M is employed communicating at the
proper moment through the cylinder J and exterior piston H by suitable ports
with the combustion chamber I. A lift valve N is attached as shown to the top
end of the exterior piston H and it opens inwards to the combustion space I per-
mitting at the proper time the admission of the fresh charge but remaining closed
during the working stroke. The gas and air is preferably admitted to the cylinder
by an automatic valve such as having the air port P and the gas ports Q.
The balancing of the pistons and cranks may be effected by providing extensions on
the crank webs (not shown) or arranging balance weights C upon the fly wheels Y.
When the several parts of the motor are in the relative position shown in
Figures 1 and 2 of the drawings the igniter M is just causing the explosion of
a compressed charge in the chamber I. The working stroke follows and the two
pistons H and F travel apart the piston H.compressing into the space K a mixture
of gas and air to a few pounds above atmosphere. At or about the terminations
of the piston's strokes the inner edge of the interior piston over-runs the port L
in the exterior piston H which simultaneously coincides with the port L in the
cylinder J. The pressure at once falls and the valve N having now a greater
pressure on the side towards K blows open and admits a fresh charge which dis-

page_text: places the remaining combustion products through the exhaust ports L and L¹.
The return strokes of the cranks D, D, and B cause the pistons to approach again
and produce the several effects of: closing the exhaust ports L and L', compress-
ing the mixture between the pistons H and F and drawing in fresh mixture to the
reservoir or chamber K by the automatic valve O which at once closes the
valve N.
This completes the cycle of operations and provides an explosion for every
revolution of the crank shaft.
A considerable variation in the arrangement of the ports, valve gearing and
construction is illustrated diagrammatically at Figure 3. To obtain the space
required in the reservoir or chamber K in a simple manner the exterior piston H
is made of two diameters and the annular space R so produced is simply kept in
communication by ports S with the atmosphere. The exhaust is effected in the
manner first described through ports L and L' but the displacement of the total
volume by the incoming charge is through ports T and T provided respectively in
the piston H and the cylinder J as shown, instead of through a lift valve in the
piston. Electrical ignition is provided at the proper moment by a battery such
as U through the metal work of the engine at V and an insulated connection at V
and either a high tension spark gap may be arranged or an arc struck by breaking
contact. Other portions are similarly constructed and lettered to the modification
first described.
A modification to effect balancing of the engine is illustrated diagrammatically
at Figures 4, 5, and 6. Two crank shafts A1 A2 are provided axially coincident
with each other and so geared that they rotate sychronously together but in opposite
directions. Any form of gearing may be employed and that illustrated consists
in a counter shaft X geared with the shaft A¹ by two wheels c and d of equal
diameter and geared with the shaft A2 by two wheels and f also of equal diameter
but having an intermediate transmission wheel placed between to reverse the
motion. The cranks D1 and D2 are respectively connected by their rods G¹
B2 are
and G2 to the exterior piston H while the cranks Bi and
to the interior
respectively connected by connecting rods E¹ and E2
piston F. This mode of coupling causes the rotating cranks, and
the connecting rods as well as the pistons to move simultaneously in opposite
directions and thus produce a perfect balance. In this modification similar letters
indicate similar parts to the modification first described.
The oil vapour or gas required may be introduced by a separate force pump,
though when oil is used it is preferred to vapourise the same within the cylinder J
or space K by an electric current heating a surface upon which the oil is sprayed.
Surface oil from the supply tank is preferably used and to provide this the supply
pipe is hinged inside the tank by a joint and has its upper end supported by an air
ball so proportioned that the mouth of the pipe keeps about the level of the oil.
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 gas or oil motors in combination with a shaft having a crank placed
centrally between two other cranks and at an angle of 180° thereto, an inner
piston connected to the central crank and working within an outer piston, an outer
piston connected by side rods to the two outer cranks and working within a
cylinder, a combustion chamber provided between the two pistons, a reservoir for
explosive mixture provided between the outer piston and the cylinder, exhaust
ports in the cylinder and the outer piston controlled by the travel of the two
pistons, a lift valve opening inwards to the combustion chamber from the reservoir
and automatic or positively actuated valves supplying the cylinder reservoir with
gas and air, all operating substantially as described.
2. In gas or oil motors in combination with a shaft having a crank placed
centrally between two other cranks and at an angle of 180° thereto, an inner piston

page_text: connected to the central crank and working within an outer piston, an outer piston
of two diameters connected by side rods to the two outer cranks and working within
a cylinder of two diameters a combustion chamber provided between the two
pistons, a reservoir for explosive mixture provided between the large end of the
outer piston and the cylinder, exhaust ports in the cylinder and the outer piston
controlled by the travel of the two pistons, ports or passages in the end of the
outer piston and the cylinder for passing fresh mixture from the reservoir to the
combustion chamber and automatic or positively actuated valves supplying
the cylinder reservoir with gas or air all operating substantially as hereinbefore
described.
3. In gas or oil motors in combination with two coaxial shafts having two cen-
trally placed cranks on the adjacent ends between two other cranks at an angle
of 180° with the first and one on each shaft, an inner piston connected by two rods
one to each central crank and working within an outer piston, an outer piston
connected by side rods to the two outer cranks and working within a cylinder,
positive gearing connecting one crank shaft with the other in such a manner that
they revolve sychronously in opposite directions and all as a means of balancing the
several parts substantially as herein before described.
Dated this 20th day of August 1898
MARKS & CLERK,
18, Southampton Buildings, London, W.C., and
13, Temple Street, Birmingham, Agents.