Improvements in Gas and other Internal Combustion Engines.
Year: 1894

page_text: Date of Application, 17th Feb., 1894
Complete Specification Left, 19th Nov., 1894-Accepted, .16th Feb., 1895
PROVISIONAL SPECIFICATION.
Improvements in Gas and other Internal Combustion Engines.
I, DAVID DAVY, of Broom Croft, Parkhead, near Sheffield, in the County of
York, Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to further improvements in gas and other internal combustion
engines, having in view the accomplishment of the object described in my previous
applications for Letters Patent, respectively dated February 15th 1893, No. 3401,
and March 3rd 1893, No. 4696.
This object is to economize the consumption of gas or combustible vapor by
transforming into useful work a considerable portion of the heat of combustion
which would otherwise be carried off by the water-jacket.
As in my before mentioned applications, the burning gases are caused to mix
with, heat, and expand, a relatively large volume of compressed air which in
expanding acts on the motor-piston, the explosive charge and the compressed air
being kept separate until the moment of ignition so that the richness of the
explosive mixture is not impaired, and yet a much larger aggregate proportion of
air to gas is used than is possible in other engines.
In my before mentioned applications the explosive charge and the charge of air
are separately compressed and are kept separate by a valve interposed between
the two chambers, which is opened at the proper moment to permit free communi-
cation.
The improvement has for object to enable the valve used to keep the two charges
separate and its operating mechanism, to be dispensed with so that the two
chambers are always in free communication and yet to prevent the diffusion of the
two charges into one another, until the explosion takes place.
To accomplish this, the spaces or chambers into which the two charges are
respectively compressed are connected by a neck or passage of considerably
smaller area than the working cylinder. The chamber in which the explosive
charge is compressed is situated preferably at the rear end of the working cylinder
and may be formed by the prolongation of the cylinder itself, the communicating
passage being formed by a contraction of the bore of the cylinder. The capacity
of the explosive chamber is so proportioned to the whole capacity of the working
cylinder and to the portion thereof which forms the compressed-air chamber, that
the desired proportional volumes of the explosive and compressed air charges may
be obtained.
The gas or combustible vapor is forced into the explosion chamber by a pump
and may be undiluted or slightly diluted with air, but a sufficiently large portion
of the air necessary to constitute the explosive charge must be caused to pass
through the neck or passage, from the motor cylinder to the explosion chamber,
throughout the compression stroke so as to prevent any flow of the explosive
charge into the motor cylinder, during the compression, the ignition taking place
before the explosive and compressed air charges can mix by diffusion. The gas or
vapor may be injected into the explosion chamber, either through orifices in or
near the neck or passage, or directly into said chamber. If the gas be injected
into the neck or passage, the jets issuing from the orifices should be so directed as
to ensure a thorough mixture of the gas or vapor with, and its carriage into the

page_text: explosion chamber by, the air forced out of the working cylinder into the explosion
chamber during the compression stroke.
The operation is such that the mixture within the neck or within the explosion
chamber in proximity to the neck, is sufficiently rich to be fired by usual means
which are located at this point, so that the ignition of the explosive charge will
proceed from the front rearwards, in order that only burning gases shall be
projected into the compressed air charge in the working cylinder.
The operation is as follows:-During the inhaling stroke, the working piston
draws in air through a valve, situated preferably in the explosion chamber, whilst
the pump draws in gas or combustible vapor. On the return stroke the gas or
vapor is injected as above described whilst the air in the working cylinder is
compressed. During the compression stroke the backward rush of air passing
through the neck or passage from the working cylinder to the explosion chamber,
in order to form an explosive mixture therein, prevents any of the gas or vapor
entering the working cylinder, the ignition taking place before diffusion can
'occur.
The explosive charge ignited towards the front of the explosion chamber burns
backwards and the burning gases are, by the force of the explosion, projected
forwards into the compressed air interposed between them and the working piston,
thereby heating and expanding said air, and causing it to do work on the
piston.
The gas pump may be driven at half speed of the working piston or may make
an idle stroke during the explosion and exhaust strokes of the working piston. Or
the engine might be of the twin type so as to obtain an explosion at each revolution
of the crank in which case the pump would deliver at each stroke to one or the
other of the explosion chambers.
The relative arrangement of the explosive and air charges might be reversed by
the explosion chamber being carried on the working piston and the compressed air
space being situated at the rear end of the cylinder, the gas or combustible vapor
being injected through sliding or jointed pipes to accommodate the motion of the
piston.
Dated this 17th day of Wahun 1904
DAVID DAVY,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.
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:-
My improvements in gas and other internal combustion engines have in view the
accomplishment of the same object as my previous inventions for which Letters
Patent were granted. to me, respectively dated February 15th 1893, No. 3401, and
March 3rd 1893, No. 4696. This object is to effect economy by transforming into
useful work a considerable portion of the heat of combustion which would otherwise
be carried off by the water jacket. This is done by compressing the explosive
charge, and likewise a charge of pure air, in communicating chambers or spaces so
that part of the burning gases will mix with, and heat, the compressed air charge
which thereby acquires an increased tension equivalent to the heat thus imparted
to it and acts conjointly with the burning gases, in the explosion chamber in
performing work on the piston or pistons. The explosive charge, and the charge

page_text: of compressed air, being prevented from mixing up to the moment of ignition, the
richness of the foriner is not impaired and the aggregate proportion of air to gas is
much greater than is possible in other engines.
In the engines specified in my previous Patents aforesaid, the explosive and
compressed air charges were kept wholly separate during the compression stroke
and were put into communication at a given moment by the opening of a
vilve.
My present improvements are designed to enable this valve and its operating
mechanism to be dispensed with and notwithstanding that free communication is
maintained between the two charges to prevent them mixing during the compression
stroke by diffusion of the explosive charge into the compressed air charge. To
accomplish this, the spaces or chambers in which the two charges are respectively
compressed are connected by a neck or passage of relatively small area and the
admission and compression of the gas and air are so effected and controlled that
during the whole of the compression stroke there shall be produced a sufficient rush
of air through this neck from the compressed air space to the explosion space to
prevent any flow of gas or explosive mixture in the opposite direction, the quantity
of air so passing through the neck not being such as to excessively dilute the gas
in the explosion chamber. When, as in my Patent No. 3401, the gas or explosive
charge is inhaled by a working piston, provision may be made to maintain the flow
of air through the neck, as above mentioned, during the inhaling stroke as well as
during the compression stroke. The ignition of the explosive charge is effected at
a point near the neck or communicating passage so that the combustion of the
charge will proceed as it were backwards through the mass of the charge in order
that only burning gases shall be projected into the compressed air charge by the
initial force of the explosion which might otherwise cause part of the unignited
charge to be projected into the air charge.
The invention will be described with reference to the accompanying drawings,
forming part of this Specification, wherein
Figures 1, 2, 3, illustrate the invention as applied to an engine such as described
in my former Patent No. 3401 of 1893. Figures 4, 5, 6, 7, represent a similar
engine wherein the two pistons and cylinders are placed concentrically in line.
Figures 8, 9, 10, 11, represent a modification of the same engine.
Figures 12, 13, 14, illustrate one arrangement of engine such as described in my
former Patent No. 4696 of 1893, where one working piston and a pump are used.
Figures 15, 16, 17, 18, illustrate another arrangement of the same kind of engine.
The same letters of reference indicate the same parts in all the figures.
Referring to Figures 1 to 7, A and B are the two cylinders and A' and B' are
the corresponding pistons coupled to the same crank so as to work together.
C is a neck or passage by which communication is maintained between the two
cylinders.
In Figures 1, 2, 3, a is the air compression space within the cylinder A and the
space within the cylinder B into which the explosive charge is compressed. d is
the air inlet valve to admit air only to cylinder A and e the inlet valve to admit
mixed gas and air to cylinder B, being the gas inlet valve. The valve d is
situated within the cylinder A and the valve e is situated in the neck or passage C.
is the exhaust valve and g the ignition tube. The piston A¹ works so much
closer than the piston B' to the end of its cylinder that although the strokes of the
two pistons are equal the capacity of the space a relatively to the whole capacity of
cylinder A is so much less than that of the space 6 relatively to the whole capacity
of cylinder B that during the compression stroke some of the air charge contained
in A will be forced through the passage C so as to prevent any gas passing in the
reverse direction into cylinder A.
In order to prevent any flow of gas towards cylinder A during the inhaling
stroke, the volume of gas and air admitted through valve e may be so restricted
that in order to complete the volume of the explosive charge, air would be
drawn towards B from valve d, the proportion of gas to air in the mixture

page_text: admitted at being greater than that required for the explosive charge which is
further diluted to the necessary extent by the air coming from valve d.
Referring now to Figures 4, 5, 6, 7, the pistons A', B₁, are in one with each
other and of different diameters. The space a into which the charge of air is
compressed is connected with cylinder A by a passage a' and with the explosion
chamber by the neck or passage C by which, as before described, the spaces a
and bare in constant free communication.
In Figures 8, 9, 10, 11, the neck or passage C connecting the spaces a and b is
formed longitudinally through the piston B' which, as in Figures 4 to 7, is formed
in one width, and is of lesser diameter than, piston A¹. The compressed air
space a is, in this case, formed by the clearance between the piston A' and the
end of the larger cylinder A and the neck or passage C opens to it through
the side of piston B', the explosion chamber being at the other end of the
cylinder B.
The operation is as follows:-During the inhaling stroke a rich mixture of gas
and air is drawn into cylinder B through valve e and a charge of air is drawn into
cylinder A through valve d, the opening of the valve e being restricted in relation
to valve d so that air will pass from chamber a to chamber b through the passage C.
The capacities of the compression spaces a, b, are so proportioned to the whole
capacities of the respective cylinders that whilst the capacity of the air compression
space a may be the greater, the pressure of the air in that space will throughout
the compression stroke be superior to that in the explosion space b so that there
will be a flow of air through the neck C from a to' b in opposition to which no air
and gas mixture can pass in the reverse direction.
In Figures 12 to 18, there is only one working piston, P being a pump which
during the inhaling stroke draws in gas and air or gas only; whilst the working
piston A¹ draws in air only through the valve d. As before, the explosion
chamber is connected with the air compression space a by a neck C, the capacity
of the chamber & being so proportioned to that of the working cylinder and of the
space a, that the desired flow of air from a to b through the neck C will be produced
by the compression stroke, whilst the charge contained in the pump cylinder P is
delivered through the valve p.
In Figures 12, 13, 14, the pump delivers a mixture of gas and air directly into
the chamber 6 whilst in Figures 15, 16, 17, 18, the pump delivers gas only, through
the valve p, into the neck C, the gas being carried into the explosion chamber
by the rush of air through the neck by which, as before explained, the passage of any
of the gas into the working cylinder is prevented. The gas passage opens
laterally into the neck C immediately opposite to the orifice o' in the opposite side
of the neck at which the ignition tube is connected. The gas pump P is shewn, in
Figures 15 to 18, as worked direct from the piston crosshead, in which case it
would work idly during the explosion and exhaust strokes, but the pump might be
driven at half speed of the working piston, its delivery valve being so controlled as
to deliver only during the compression stroke. The exhaust valve is situated in
the explosion chamber the air and burnt gases contained in the cylinder A
exhausting through the neck C and chamber b.
The ignition tube communicates, in all cases, with the chamber b at a point as
near as possible to the orifice of the neck C so that whilst the flame is being
propagated through the explosive mixture in the first effect of the explosion
will be to project some of the burning gases into the chamber a. The heat
thus imparted to the compressed air charge will increase its tension and he
converted into useful work, the burning charge and the heated compressed air
charge expanding and performing work conjointly on the pistons or piston, as the
case may be.
It will be obvious that in Figures 4, 5, 6, 7, 8, 9, 10, 11, the relative positions of
the compressed air and explosive charges may be reversed without affecting the
operation of the engine, it being only necessary to arrange the positions of the
valves and ignition tube accordingly.

page_text: In Figures 12, 13, 14, the same change may be made but in that case the pump 1
would pump air and the piston A' would draw in gas and air, as shewn in certain of
the figures of my prior Patent No. 4696.
It will, also, be obvious that combustible vapour, generated in a separate
vapourizer, may be supplied instead of gas, whilst the explosion chamber may, in
all cases, be kept sufficiently cool by water jackets or by radiating ribs cast on the
outside.
Having now particularly described and ascertained the nature of the said inven-
tion, 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 working on the four-phase cycle,
wherein the mixture of gas and air is compressed into an explosion chamber or
space, and a charge of air only is compressed into another chamber or space, the
two chambers or spaces being permanently in free communication by a narrow
passage or neck to allow of the burning gases being projected by the force of the
explosion into the air charge, and wherein the compression of the air charge
causes throughout the compression stroke a rush of air through the passage or
neck from the air space to the explosion space in order to prevent the premature
passage of the gas charge in the reverse direction, substantially as specified.
2. A gas or other internal combustion engine wherein the chambers or spaces
which receive the explosive and air charges are permanently connected by a
narrow passage or neck and wherein the gas to form the explosive charge is
injected into the said neck and is carried into the explosion chamber by the
rush of air through the neck produced by the compression of the air charge, as
specified.
3. A gas or other internal combustion engine wherein explosive and air charges
are respectively compressed into chambers or spaces which are permanently
connected by a narrow passage or neck, as specified, and wherein the ignition of
the explosive charge is effected at such a point that the combustion will proceed
backwards through the explosive charge and only burning gases will be projected
into the compressed air charge, as and for the purpose specified.
200
A. M. & WM. CLARK,
53, Chancery Lane, London, Chartered Patent Agents.