Improvements in Gas Engines or other Internal Combustion Engines.
Year: 1893

page_text: Date of Application, 15th Feb., 1893
Complete Specification Left, 15th Nov., 1893-Accepted, 15th Feb., 1894
PROVISIONAL SPECIFICATION.
Improvements in Gas Engines or other Internal Combustion
Engines.
I, DAVID DAVY of Broom Croft, Parkhead, Sheffield, in the County of York,
Engineer, do hereby declare the nature of this invention to be as follows:-
The object of this invention is to utilize, by transforming into useful work, a
considerable portion of the heat (resulting from the combustion of an explosive
mixture in the working cylinder of a gas or other internal combustion engine)
which would otherwise be carried off by the water-jacket.
For the accomplishment of this object I employ what may be termed a duplex
engine working on the four-cycle principle and whereof the two cylinders are in
free communication with one another, the phases of operation being concurrent and
similar except that in one an explosive mixture and in the other air only is employed
so that the explosion occurs in one cylinder only but part of the burning charge is
projected by the force of the explosion into the other cylinder thereby raising the
temperature and pressure of the compressed charge of air therein contained, the
resultant pressure being equal in the two cylinders and the work performed on
the two pistons being transmitted by usual means to the crank shaft of the
engine.
The two cylinders may be side by side or concentric and the two pistons may be
equal or unequal in diameter and stroke but in order that the heat generated by
the explosion may be utilised to the utmost extent possible the capacity of the air
cylinder may be the greater of the two. The air and gas inlets may be so arranged
that the whole of the air for the charges of both cylinders will be admitted through
the air cylinder whilst the gas necessary to form an explosive mixture is admitted
only to the explosion cylinder so that the explosive and non-explosive charges are
so far virtually isolated from each other that none of the explosive charge will find
its way into the air cylinder until the explosion occurs and consequently a highly
inflammable mixture may be employed although the proportion of air to gas in the
aggregate charges of both cylinders is much greater than it is possible to use in
single cylinder engines whereby economy of working is obtained.
Dated this 15th day of February 1893.
COMPLETE SPECIFICATION.
Improvements in Gas Engines or other Internal Combustion
Engines.
I, DAVID DAVY of Broom Croft, Parkhead, Sheffield, in the County of York,
Engineer, do hereby declare the nature of this 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 this invention is to utilize, by transforming into useful work, a
considerable portion of the heat (resulting from the combustion of an explosive

page_text: mixture in the working cylinder of a gas or other internal combustion engine)
which would otherwise be carried off by the water-jacket, and obtain more perfect
combustion of the exploded charge. For the accomplishment of this object I
employ what may be termed a duplex engine working on the four-cycle principle
and whereof the two cylinders are in free communication with one another, at least
during the explosion or working stroke, the phases of operation being concurrent
and similar, except that in the one cylinder an explosive mixture, and in the other
cylinder air alone, is employed. The two cylinders inhale their respective charges
to the full extent on the outward or inhaling stroke of their pistons and compress
those charges to an equal extent on the inward or compression stroke. Upon the
ignition of the explosive charge in the one cylinder, explosion occurs in that
cylinder only but owing to the superior pressure thereby generated in that cylinder
part of the burning charge is projected into the other cylinder where it mingles
with the already compressed charge of air therein contained and imparts thereto
some of the surplus heat which it would otherwise lose to the water-jacket, thereby
raising the pressure of the compressed air charge. Thus the same amount of gas
may be made to heat and expand, in the aggregate, twice the maximum proportion
of air that it has heretofore been possible to work with. The work performed on
the one piston by the explosion of the gaseous mixture, and on the other piston by
the heating and expansion of the compressed air, is transmitted by usual means
to the crank-shaft of the engine. The two cylinders are preferably side by side
but they might be concentric, and the two pistons may be equal or unequal in area,
but in order that the heat generated by the explosion may be utilised to the utmost
extent possible the capacity of the air cylinder should not be less than that of the
explosion cylinder and may be the greater of the two.
Reference is to be had to the accompanying drawings, forming part of this
Specification, wherein
Figure 1 is a half-sectional plan of as much of the engine as is necessary to
illustrate the invention.
Figure 2 is a longitudinal section through the air cylinder.
Figure 3 is a cross-section through the explosion chambers and valves of both
cylinders.
Figure 4 is a rear end elevation.
The same letters of reference denote like parts in all the figures.
A is the compressed air cylinder and B the explosion cylinder arranged side by
side and connected at the rear end by a passage C, the communication being in
this example controlled by a valve D worked through a lever d from a cam don
the counter shaft from which the other valves are worked in the usual manner.
Throughout the full inhaling stroke the cylinder A inhales air only through the
air valve a whilst the cylinder B inhales gas and air (supplied separately in proper
relative proportions to form a rich explosive mixture) through a valve b. E is
the exhaust valve attached to cylinder B but common to both cylinders. The
valve D is provided, and kept closed during the suction and compression strokes,
as a measure of precaution to prevent the possibility of the explosive charge in
cylinder B mingling with the air in cylinder A (or vice versa) before the explosion
as were this to happen the richness of the explosive charge might be diminished to
such an extent as to interfere with its ignition. In the engine shewn the valve D
is opened during the working and exhaust strokes, but by providing an exhaust
valve for each cylinder the valve D might remain closed during the exhaust stroke
The object of exhausting the air cylinder through the combustion cylinder is to
assist in clearing out the residual products therefrom. As regards the water-jacke
with which the engine is shewn to be provided it is to be remarked that the
absorption of heat and its conversion into useful work by the compressed ai
charge in the cylinder B renders the use of a water-jacket less necessary than in
other engines and may possibly enable the use of the water-jacket to be
dispensed with altogether. The ignition of the explosive mixture is effected in
either of the known ways.

page_text: Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I would observe that I
lay no claim to a duplex engine having communicating cylinders with pistons
moving concurrently in the same direction, but I declare that what I claim is :-
1. A gas or other internal combustion engine working on the four-phase cycle
having two cylinders communicating during the working stroke and whose pistons
perform the same phases concurrently but the one inhaling air only and the other
an explosive charge, the charges in the two cylinders being compressed to
substantially the same pressure and the gases of combustion in the one cylinder
being projected into and mingling with the compressed air in the other cylinder so
as to impart heat thereto and convert the heat into useful work by the expansion
of such air, as specified.
2. A gas engine wherein part of the surplus heat of the gases burnt in one
cylinder is converted into useful work in another cylinder by being absorbed by a
charge of compressed air contained in such other cylinder so as by the expansion
of said air to operate the piston of said cylinder, as specified.
3. The herein described improved gas or other internal combustion engine
operating substantially as herein specified.
Dated this 15th day of November 1893.
By A. M. & Wm. Clark,
D. DAVY,
53, Chancery Lane, London, Chartered Patent Agents.