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

page_text: Date of Application, 3rd Mar., 1893
Complete Specification Left, 4th Dec., 1893-Accepted, 3rd Mar., 1894
PROVISIONAL SPECIFICATION.
Improvements in Gas and 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 economize the consumption of gas or com-
bustible vapor by causing the burning gases to heat and expand a relatively large
volume of air preferably interposed between the combustible charge and the
working piston, the explosive charge and the air being compressed to about the
same degree but contained in different chambers so as to remain or be kept
separated until by the ignition of the former the burning gases are caused to
expand into, mix with, and highly heat, the air contained in the working cylinder,
the surplus heat of the burning gases being thus converted into work by the
expansion of the air.
By thus separating the inflammable mixture in the combustion chamber from the
compressed air contained in the working cylinder until the point of ignition, a
rich mixture may be used in the former and yet a much larger aggregate
proportion of air to gas may be used than is possible in gas engines of the Otto or
similar type.
The working cylinder inhales and compresses air only whilst the inflammable
mixture is supplied to the combustion chamber by a pump, the communication
between the working cylinder and its combustion chamber being if necessary
controlled by a valve opened from the engine shaft, or by the force of the
explosion, at such point in the compression stroke that the combustible charge is
about to be, or has been, brought to the point of ignition and remaining open
during the working and exhaust strokes and preferably during the inhaling stroke
also, the mixed air and burnt gases exhausting from the cylinder through the
combustion chamber.
In order that the engine may economically work upon the four-cycle principle,
there may be two working cylinders each provided with a separate combustion
chamber and one pump supplying both, the phases of working in the two cylinders
being so timed that the first phase in the one coincides with the third phase in the
other, and so on, whilst the pump inhales and compresses at each revolution of the
engine a combustible charge which it delivers to the combustion chamber of the one
and of the other cylinder alternately, the communication of the pump with the
combustion chambers being controlled by valves.
Dated this 3rd day of March 1893.
COMPLETE SPECIFICATION.
Improvements in Gas and 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, like that of my previous invention described in my

page_text: application for Letters Patent dated the 15th day of February 1893, No. 3401, is
to economize the consumption of gas or combustible vapor by transforming into
useful work a considerable portion of the heat (resulting from the combustion of an
explosive mixture in a gas or other internal combustion engine) which would
otherwise be carried off by the water-jacket.
According to the present invention the surplus heat of the burning gases is
caused to heat and expand a relatively large volume of compressed air which in
expanding acts directly or indirectly on the working piston, the explosive charge
and the air being kept separate until the moment of ignition whereupon the burning
gases expand into and mix with the air so as to quickly impart thereto their surplus
heat which is converted into useful work by the expansion of the air within the
working cylinder or within a chamber in connection therewith.
By keeping the inflammable mixture separate from the compressed air until the
point of ignition, the richness of the mixture is not impaired and yet a much larger
aggregate proportion of air to gas is used than is possible in gas engines of the Otto
or similar type.
The air by which the surplus beat of the combustible charge is thus absorbed
is preferably interposed between the said charge and the working piston, but
the relative arrangement may be reversed without materially affecting the
operation.
The engine may have either one or two working cylinders and one or more
pumps, and may work on the four-phase cycle or with an explosion at every
revolution or at every stroke.
Reference is to be had to the accompanying drawings, forming part of this
Specification, wherein
Sheet I represents an engine with a single working cylinder, Figure 1 being a
horizontal section through the working and pump cylinders, Figure 2 a longitudinal
vertical section through the pump cylinder, and Figure 3 a cross-section through
the combustion chamber.
Sheet II represents in Figures 4, 5, 6, precisely similar views of an engine
having two working cylinders, the construction of the engine (save that the working
cylinder and its combustion chamber and valves are duplicated) being precisely
similar to that shewn on Sheet I whilst the operation differs only in that every
stroke of the pump is useful instead of, as in Sheet I, every alternate stroke of the
pump being an idle one.
Sheet III shews in Figures 7, 8, 9 & 10 similar views of an engine differing only
in construction and operation from that shewn in Sheet I in that the air is not
interposed between the explosive charge and the working piston, this modification
being equally applicable to the engine shewn in Sheet II.
Sheet IV illustrates the application of the invention to an engine having an
explosion at each outward stroke of the working piston. The same letters of
reference indicate corresponding parts in all the figures.
Referring to Sheets I, II, and III, A is the working piston, B the pump piston
working in twin cylinders placed side by side, the pistons being coupled to the
same crank so as to move simultaneously in the same direction. The pump
piston B works close up to the end of its cylinder, with only the necessary clearance
whilst the piston A when at the end of its inward stroke is sufficiently distant from
the end of its cylinder to leave space for the proper compression of the air or of
the explosive mixture, as the case may be. C is a chamber at the ends of the
pump and working cylinders into which the charge from the pump cylinder is
compressed by the pump piston, said chamber communicating with the working
cylinder through a valve D and with the pump cylinder through a valve E. Fis
an air inlet valve, G is the gas inlet valve, H the mixed gas and air inlet valve,
K the exhaust valve.
The operation of the engine shewn in Sheet I is as follows, it being understood
that all the valves (except valve F which is automatic) are opened and closed at
the proper times by cams, or their equivaleut, operated from the main shaft of the

page_text: engine. On its outward stroke the working piston A draws in a charge of air
through Fat same time that the pump piston B draws in a charge of inflammable
mixture through valves G and H. On the return stroke both these charges are
compressed to about the same degree, the air into the space behind piston A while
the inflammable mixture is forced through valve E into chamber C. At the end of
this stroke the valve D is opened, the valve E is held closed, and the charge in C
is ignited by the usual means, whereupon the outward stroke is made by the
expansion of the burning gases and of the air acting on the piston A in the working
cylinder, the valve D remaining open throughout this stroke and the expansion of
the air being due to the transmission thereto of part of the heat of the burning
gases projected into its midst. During this stroke the pump piston makes an idle
stroke. At the end of the stroke the exhaust valve K is opened and the products
of combustion (except. such as may remain in the clearance spaces) are cleared out
and the cycle is then repeated.
The operation of the engine shewn in Sheet II differs only in that the pump B
compresses the explosive charge alternately into the one or other of the two
chambers C, so that every stroke of the pump is a useful one, the phases of working
in the two cylinders A being so timed that the first phase in the one coincides with
the third phase in the other, and so on, the pump inhaling and compressing at every
revolution of the engine.
In Sheet III the operation only differs in that the pump inhales air through
valve F whilst the working cylinder inhales the inflammable charge through
valves G, H, which in this case communicate direct with the working cylinder.
The air inhaled in the pump cylinder is compressed in chamber C at same time
that the inflammable charge is compressed to about the same degree in the working
cylinder. At the end of this stroke the valve D is opened, the valve E is held
closed, and the inflammable charge is ignited, whereupon the outward stroke is
made by the expansion of the burning gases, and the expansion of the air in the
chamber C into which part of the burning gases is projected thereby heating and
expanding the air therein, valve D remaining open throughout this working stroke
at the end of which the exhaust valve K is opened, the products of combustion
exhausted, and the cycle repeated.
Sheet IV shews in Figure 11 a horizontal section of an engine in which an
explosion is obtained at each outward stroke of the working piston. The parts A
to K are similar to, and fulfil the same functions as in, Sheet I except that the
charge of air instead of being inhaled by the working piston is supplied by a
second pump M through a valve L controlling communication between it and
the working cylinder A, the pump piston being coupled to the same crank as the
pistons A B. The cycle of operation is as follows:-At each outward stroke the
working piston is propelled by the force of an explosion whilst the pump B draws
in a combustible charge through G, H, and pump M draws in a charge of air
through F. When the working piston A reaches nearly the end of the outward
stroke the exhaust valve K is opened and remains open during the greater part of
the inward stroke, at the same time the combustible mixture is being compressed in
the pump cylinder B and the air in the pump cylinder M. Just before the
completion of the inward stroke the exhaust valve K is closed and the valve E
between the pump B and chamber C is opened to admit the compressed combustible
charge to chamber C at same time that valve L is opened to admit the compressed
air charge to the working cylinder A. Upon the ignition of the combustible
charge in C by any usual means the force of the explosion acts upon the working
piston by its own expansion and by heating and expanding the compressed air charge
in the working cylinder as before described.
It will be obvious that the functions of the pumps B and M might be reversed, in
order to pump compressed air into C and the explosive charge into A in order to
obtain the same effect, the explosion, however, taking place in the working cylinder
and expanding the air in the chamber C, as described in reference to Sheet III,

page_text: It will also be obvious that by making the pump and working pistons double-
acting an explosion at each outward and inward stroke may be obtained.
In all the arrangements the walls of the compressed air space, whether chamber C
or the part of the working cylinder through which the piston does not travel, may
be lined with fireclay or other refractory material so as to act as a regenerator to
store part of the heat of the explosion and impart it to the incoming charge of
compressed air.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what I
claim is :-
1. A gas or other internal combustion engine having a working cylinder and one
or more pump cylinders and wherein the explosive charge and a charge of air are
separately compressed, the one in the working cylinder and the other in a chamber
separate from the working cylinder but put into communication therewith at the
proper moment, so that the gases of combustion will be projected into and heat the
compressed air, the air and gases re-acting conjointly on the working piston, as and
for the purpose specified.
2. The respective. gas or other internal combustion engines constructed and
arranged to operate substantially as herein specified and illustrated in the respective
sheets of drawings hereunto annexed.
....ב
this ich dr of Damoh^- 1902
By A. M. & Wm. Clark,
D. DAVY,
53, Chancery Lane, London, Chartered Patent Agents.
D. DAVY,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.