IMPROVEMENTS IN ENGINES WORKED BY PRODUCTS OF COMBUSTION EITHER ALONE OR IN CONJUNCTION WITH OTHER ELASTIC FLUID
Year: 1877

page_text: LETTERS PATENT to Matthew Piers Watt Boulton, of Tew Park, in the
County of Oxford, for the Invention of "IMPROVEMENTS IN ENGINES WORKED
BY PRODUCTS OF COMBUSTION EITHER ALONE OR IN CONJUNCTION WITH
OTHER ELASTIC FLUID."
Sealed the 24th April 1877, and dated the 24th February 1877.
PROVISIONAL SPECIFICATION left by the said Matthew Piers Watt
Boulton at the Office of the Commissioners of Patents on the 24th February
1877.
MATTHEW PIERS WATT BOULTON, of Tew Park, in the County of Oxford..
"IMPROVEMENTS IN ENGINES WORKED BY PRODUCTS OF COMBUSTION EITHER
ALONE OR IN CONJUNCTION WITH OTHER ELASTIC FLUID."
This Invention relates to engines worked by products of combustion either alone
or in conjunction with other elastic fluid.
The products employed may be derived from the combustion of an inflammable
gaseous mixture, one ingredient of which may be air or oxygen, or gas containing
oxygen, while the other may be an inflammable gas or vapour, or a mixture thereof
with air or other elastic fluid. Otherwise one ingredient used for combustion may
be air or elastic fluid, carrying in suspension particles of combustible matter, either
liquid or solid.
In the following description I shall for simplicity speak of gas and air as the
materials used for combustion, it being understood that the constructions described
are also applicable when other materials such as above mentioned are employed.
Also I shall suppose the elastic fluid to act on a piston in a cylinder, and where the
heat is employed to generate vapour I speak of this as vapour of water or steam.
But the elastic fluid may be employed to work an engine of any known construction,
such as the various forms of rotary apparatus, and instead of water other liquids may
be employed for the generation of vapour.
I employ two cylinders, each fitted with a piston; I shall call one of these the
charging cylinder; the charge of inflammable mixture is admitted into it and ignited
in it. In the other, which I shall call the main cylinder, the piston which drives
the engine, works. Between these two cylinders is a valve worked by the engine.

page_text: After the ignition of the inflammable mixture in the charging cylinder this valve is
opened, and this opening takes place gradually, so that the elastic fluid passing from
the charging cylinder to the main cylinder is at first wire-drawn and the pressure
on the piston in the main cylinder is raised gradually so as to avoid violent shock.
For a double-acting engine a separate charging cylinder is employed in connection
with each end of the main cylinder.
The cooling of the hot products of combustion may be effected in various
manners.
In one method air or elastic fluid is compressed by the engine, and after the
piston in the main cylinder has performed part of its stroke a portion of this
compressed air or fluid is admitted through a valve into the charging cylinder
where it mixes with the hot products of combustion, and the mixed and cooled
elastic fluid acts on the piston in the main cylinder. I have described this method
of operating in the Specification of a Patent granted to me on the 15th day of
September, 1876, No. 3620.
In another plan the cylinders are surrounded by a casing of water, the vessel
containing this water forming portion of a boiler, and the steam generated from this.
water rising to a steam space whence it passes to perform work. It may be used
for this purpose either in conjunction with the products of combustion or separately,
the latter plan being preferable when it is desired to condense the steam.
In another method of construction I cause the hot products of combustion to
come into direct contact with water or wetted bodies, and so generate steam, which
acts along with them in the main or working cylinder. For this purpose I place
between the charging cylinder and the main cylinder an apparatus which I shall
term an evaporating frame, which is wetted with a certain quantity of water
between each stroke, and the hot products of combustion passing through passages
in this frame convert the water into steam, which acts, together with the products'
of combustion, on the piston of the main cylinder.
The wetting of the evaporating frame may be effected in various ways. I prefer
generally to do it by giving a motion to the frame so as to dip it in water.
Another plan is to cause the water to move so as to wet the material.
The evaporating frame may consist of one or more thicknesses of wire gauze
or perforated metal, or it may consist of numerous plates, or tubes, or rods
having narrow passages between them, or it may contain porous material such as
asbestos.
Fig. 1 represents a construction suitable for being employed when compressed air
is used as the cooling agent, shewn as applied at one end of the main cylinder.
Here A is the charging cylinder into which the inflammable mixture is introduced,
and in which it is ignited. P is the piston working in this cylinder V₁, and V2 are
the valves (which may be self-acting as shewn) by which the inflammable mixture
is introduced. S is the valve or slide by which the compressed air or elastic fluid
is introduced from the vessel or reservoir containing it. e¹ and e² are ports by
which the fluid in the cylinder A passes to a compound slide B which governs
these ports, and also an eduction passage x. a is a port leading into the main
cylinder C.
The operation takes place as follows:-I shall suppose the piston P to be at the right-
hand end of the cylinder A, and this cylinder filled with inflammable mixture which
has entered it by the valve v¹. The piston in the main cylinder C is at the right-hand
end of its stroke, and the slide B is in such a position as to close the port e¹ without
opening . Ignition of the inflammable mixture is caused to take place by means of
any known apparatus suitable for the purpose, which being no part of my present
Invention is not shewn in the Figure. Immediately after this the slide B is moved
towards the left so as to open the port e¹, from which there is communication
through the slide B to the port a. The port e is thus opened gradually, so as to
prevent shock to the piston in the main cylinder C. The products of combustion
enter the cylinder C and act on its piston, urging it towards the left. After the
piston in the main cylinder has performed a certain portion of its stroke the valve S
i

page_text: is opened by the engine and the compressed air or elastic fluid enters the cylinder A.
It mixes with the fluid in it, reducing its temperature, and passes with it to the
main cylinder C, co-operating with it in driving the piston. After a sufficient
quantity of it has been admitted the valve S is closed and communication with the
reservoir of compressed air cut off.
The movement of the valve S may be varied in the manner of an expansion slide
so as to vary the charge of air admitted as desired. The piston in the main cylinder
proceeds to the end of its stroke. During the period above described the piston P
in the cylinder A remains stationary. The piston in the main cylinder now com-
mences its return stroke, the slide B being moved to the extreme of its stroke
towards the left, establishing communication between the ports e¹, a, and x, and
closing the port e. The piston P now makes its stroke from right to left, expelling
the elastic fluid in front of it, while it is followed behind by a fresh charge of in-
flammable mixture entering by the valve V2, and which at the end of the stroke
fills its cylinder. Meanwhile the piston in the main cylinder is making its return
stroke, driving out the exhaust products in its cylinder through the body of the
slide B and the eduction passage a, and it attains the end of its stroke some little
time after the piston P has attained the end of its stroke. When it attains the end
of its stroke the inflammable mixture is ignited and the operations previously
described are repeated, the piston in the main cylinder making its stroke again.
towards the left. When this stroke has been completed during the next return
stroke in the main cylinder the operations previously described are repeated, the
valve and the port e performing the functions previously performed as described
by the valves v² and e¹. And the piston P makes a stroke from left to right, being
followed by the inflammable mixture which at the end of its stroke fills the cylinder
A. The position of the parts is now the same as that supposed at the commencement
of the description, and the cycle of operations is ready to be repeated. The
slide B and faces may be cooled by passage of cold water through ducts provided
for the purpose. Also instead of a single slide, separate slides or valves may be em+
ployed to operate in the order described above. When the engine is double-acting,
apparatus such as above described is provided at both ends of the cylinder, the
piston in such case being driven in both directions by the pressure of the elastic
fluid applied as above described.
-
In the construction above described the contents of the cylinders may either be
discharged into the atmosphere or into a refrigerator or chamber kept cool by water
in any known manner, whence it is extracted by a pump or extracting apparatus..
The movement of the piston P in the charging cylinder may be effected by a cam or
other suitable apparatus worked by the engine; or when a refrigerator kept at low-
pressure is used, as above mentioned, it may be worked by means of the pressure of
the entering charge of inflammable mixture. It may also be worked by means of
a subsidiary piston attached to it- and working in a cylinder which is connected at
suitable times with a chamber maintained by the engine either at high or at low
pressure.
Instead of employing a rectilineally moving piston, as shewn in the Figure, a
rotary reciprocating piston might be employed. A construction generally similar
remains applicable when the requisite cooling is effected by means of water applied
externally, and the use of compressed air is dispensed with. In this case the heat
imparted to the water may be utilised for the generation of steam as I have
previously mentioned. The steam eo generated may be admitted by the valve S in
lieu of the compressed air, or otherwise it may be admitted directly into the work-
ing cylinder through a valve provided for the purpose. Otherwise the steam may
perform work apart from the products of combustion as previously noticed. In this
case it may work in a separate cylinder or engine, or the products of combustion
and the steam may work in the same cylinder on opposite sides of its piston which
may be a differential one. When the steam is used conjointly with the products of
combustion, I prefer generally to cause the elastic fluid to act in two cylinders, a
high pressure and low pressure one. The first of these is cooled by the water

page_text: casing, and within this the heat of the elastic fluid is reduced to a certain degree,
while it finishes its expansion in the second or low-pressure cylinder, which is not
cooled by any external cooling agency. The construction of engine remaining the
same, the steam employed may be generated by an independant source of heat, the
water casing being dispensed with. Or as is obvious, steam generated in both ways
may be employed.
Fig. 2 shews one form of construction applicable when the products of combustion
are brought into direct contact with water, the steam generated from this passing
along with them into the main cylinder and acting there in conjunction with them.
In this Figure, A is the charging cylinder and Pits piston; v, the valve for the
admission of the inflammable mixture; e, that for the outlet of the contents of the
cylinder A, B, a slide which controls the port u, forming a communication between
the main cylinder C and the evaporating chamber m, n, in which there is an
evaporating frame D, such as has been previously described; o, a passage leading
from n to the further end of the cylinder A; x, an eduction passage which as well
as the port u is controlled by the slide B.
.
The operations take place as follows:-I suppose the piston P to be at the right-
hand end of its cylinder A, and this to be full of the inflammable mixture supplied
by the valve v. The slide B is in such a position as to close the ports u and x. The
mixture is ignited, upon which the pressure opens the valve e, and products of com-
bustion pass from the cylinder A through the evaporating chamber n, and the
passage o to the other side of the piston P, so that the pressure on this piston is
equalised. The slide B is moved by the engine opening the port u gradually, so as
to avoid shock on the piston in the cylinder C, and elastic fluid consisting of cooled
products of combustion and steam enters that cylinder and urges its piston towards
the left. Simultaneously the piston P is moved by the engine towards the left,
driving in front products of combustion through the evaporating chamber n, while
the mixture of products of combustion and steam enters the cylinder A behind it.
The pistons proceed in this way to the end of their strokes, at which period the
pressure in both cylinders is reduced to the lowest point desired. The slide B is
then moved towards the right by the engine so as to bring the port u in communi-
cation with, and also to open x to the chamber n. The pistons then make their
return strokes, expelling the contents of both cylinders through the exhaust
passage ; while a fresh charge of inflammable mixture enters the cylinder A to the
left of the piston P through the valve v. During this movement the evaporating
frame D is lowered by the engine into the water and again raised. When the
pistons have completed their return strokes, the cycle of operations is ready to be
repeated. When the engine is double-acting, apparatus such as above described is
provided at both ends of the main cylinder. The contents of the cylinders A and C
may either be discharged into the atmosphere or into a refrigerator or chamber kept
cool by water in any known manner, whence the fluid is extracted by a pump or
extracting apparatus.
In the construction above described if the evaporating chamber is omitted, the
remainder may be used in connection with the other means of effecting the cooling
previously described. For example, if compressed air is used for this purpose, the
products of combustion issuing from the cylinder A and the compressed cold air may
both be admitted into one passage leading to the main cylinder and communicating
with the passage o. Thus as the piston P advances in the cylinder A, expelling the
products of combustion from the one end of it, the mixture of these products with
cold air passes by o to the other end of the cylinder A, and fills the space behind
the advancing piston P, while at the same time the cooled mixture propels the
piston in the main cylinder C. If the cooling is effected by means of water
enveloping the cylinders the same general construction may be retained. If desired
the piston in the charging cylinder may be connected directly with that in the main.
cylinder.
In the Figures, I have represented the piston in the charging cylinder as working
rectilineally, but a rotary reciprocating piston may be employed, and the piston

page_text: need in no case fit very tightly as it acts merely for displacing the fluid contents of
the cylinder with the same pressure on both sides during its movement. The piston
of the charging cylinder instead of being worked by the engine may be detached
from it and worked by means of a subsidiary piston, as described in reference to
Fig. 1.
The methods of working above described are obviously applicable, not merely to
a single cylinder, as shewn in the Figures, but to various arrangements of multiple
cylinders such as are used with steam engines.
In all the above constructions the inflaminable mixture may be admitted into the
charging cylinder at or near the atmospheric pressure. But otherwise it may be
introduced into it at high pressure, its pressure being further raised by its ignition.
It may be raised to high pressure by means of pumps or forcing apparatus worked
by the engine. Or it may issue from vessels or reservoirs in which it is contained
at high pressure. When the ingredients of the inflammable mixture issue from
reservoirs in which they are contained at high pressure the use of the charging
cylinder may be dispensed with, its place being supplied by governors.
Fig. 3 shews a construction of this kind. Here A and B are reservoirs of
compressed oxygen and gas; C, a reservoir of compressed air or elastic fluid;
G1, G2, G3, are governors. The oxygen and gas issue out of the governors G¹ and G²
in proportions suitable for combustion, and pass through the passages e and i into
the chamber D, in which they undergo combustion. Compressed air issues out of
the governor G³ and flows through the psssage o. It meets the stream of products
of combustion flowing through the passage n out of the combustion chamber D, and
these two streams mix in the passage F of varying area; the temperature of the pro-
ducts of combustion being thus reduced to the degree desired, the mixed fluid
passes on to work the engine.
It is obvious that air or nitrous oxide might be used instead of oxygen. In these
constructions of apparatus combustion may be maintained in the combustion
chamber by means of a small jet of gas and oxygen injected into it. This may be
convenient, as it may not be desired to maintain a continuous flow of the oxygen and
gas from the main reservoirs, since the communication between this and the working
cylinder is interrupted if the elastic fluid works expansively in the cylinder.
structions of a similar nature, in which the cooling of the products of combustion is
effected by bringing them into contact with liquid which they convert into vapour,
have been described by me in the Specification of a Patent granted to me on the
31st May, 1876, No. 2288.
Con-
When the products are applied in this manner, an apparatus, such as shewn in
Fig. 4, may may be employed. Here A is a vessel containing the liquid which is
supplied by a feed pump or injector. The hot products of combustion pass down
the tube into the branches o, o, which have numerous holes i, i; b, b, are per-
forated plates or gratings or sheets of wire gauze. The products of combustion issue
from o through the orifices i, i, and ascend through the liquid passing through the
orifices in the perforated material b, b, generating vapour in their course. The
mixed products and vapour pass away by the passage e to be utilized as desired.
Before passing away the mixed fluid may be caused to pass through asbestos or
porous material.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Matthew Piers Watt Boulton in the Great Seal Patent Office
on the 18th August 1877.
MATTHEW PIERS WATT BOULTON, of Tew Park, in the County of Oxford.
"IMPROVEMENTS IN ENGINES WORKED BY PRODUCTS OF COMBUSTION EITHER ALONE
QR IN CONJUNCTION WITH OTHER ELASTIC FLUID."

page_text: inis invention relates to engines worked by products of combustion either alone
or in conjunction with other elastic fluid.
The products employed may be derived from the combustion of an inflammable
gaseous mixture, one ingredient of which may be air or oxygen, or gas containing
oxygen, while the other may be an inflammable gas or vapour, or a mixture thereof
with air or other elastic fluid. Otherwise one ingredient used for coinbustion may
be air or elastic fluid, carrying in suspension particles of combustible matter, either
liquid or solid.
In the following description I shall for simplicity speak of gas and air as the
materials used for combustion, it being understood that the constructions described
are also applicable when other materials such as above mentioned are employed.
Also I shall suppose the elastic fluid to act on a piston in a cylinder, and where the
heat is employed to generate vapour, I speak of this as vapour of water or steam ;
but the elastic fluid may be employed to work an engine of any known construction,
such as the various forms of rotary apparatus, and instead of water other liquids
may be employed for the generation of vapour.
I employ two cylinders, each fitted with a piston; I shall call one of these the
charging cylinder; the charge of inflammable mixture is admitted into it and
ignited in it; in the other, which I shall call the main cylinder, the piston which
drives the engine works. Between these two cylinders is a valve worked by the
engine; after the ignition of the inflammable niixture in the charging cylinder this
valve is opened and this opening takes place gradually, so that the elastic fluid
passing from the charging cylinder to the main cylinder is at first wire drawn, and
the pressure on the piston in the main cylinder is raised gradually so as to avoid
violent shock. For a double-acting engine a separate charging cylinder is employed
in connection with each end of the main cylinder.
The cooling of the hot products of combustion may be effected in various
inanners.
In one method air or elastic fluid is compressed by the engine, and after the
piston in the main cylinder has performed part of its stroke a portion of this com-
pressed air or fluid is admitted through a valve into the charging cylinder, where
it mixes with the hot products of combustion, and the mixed and cooled elastic
fluid acts on the piston in the main cylinder. I have described this method of
operating in the Specification of a Patent granted to me on the 15th day of Sep-
tember 1876, No. 3620.
In another plan the cylinders are surrounded by a casing of water, the vessel
containing this water forming portion of a boiler, and the steain generated from this
water rising to a steam space, whence it passes to perform work. It may be used
for this purpose either in conjunction with the products of combustion or separately,
the latter plan being preferable when it is desired to condense the steam.
In another method of construction I cause the hot products of combustion to
come into direct contact with water or wetted bodies, and so generate steam which
acts along with them in the main or working cylinder. For this purpose I place
between the charging cylinder and the main cylinder an apparatus which I will
term an evaporating frame, which is wetted with a certain quantity of water
between each stroke, and the hot products of combustion passing through passages
in this frame convert the water into steam, which acts together with the products
of combustion on the piston of the main cylinder. The wetting of this evaporating
frame may be effected in various ways; I prefer generally to do it by giving a
motion to the frame so as to dip it in water.
Another plan is to cause the water to move so as to wet the material. The
evaporating frame may consist of one or more thicknesses of wire gauze or per-
forated metal, or it may consist of numerous plates or tubes, or rods having narrow
passages between them, or it may contain porous material such as asbestos.
Fig. 1 represents a construction suitable for being employed when compressed air
is used as the cooling agent, shewn as applied at one end of the main cylinder.
Here A is the charging cylinder into which the inflammable mixture is introduced,

page_text: and in which it is ignited; P is the piston working in this cylinder; ¹ and v³ are
the valves (which may be self-acting as shewn) by which the inflammable mixture
is introduced; S is the valve or slide by which the compressed air or elastic fluid is
introduced from the vessel or reservoir containing it; e¹ and e² are ports by which
the fluid in the cylinder A passes to a compound slide B, which governs these ports,
and also an eduction passage x; a is a port leading into the main cylinder C.
The operations take place as follows:-I shall suppose the piston P to be at the right-
hand end of the cylinder A, and this cylinder filled with inflammable mixture which
has entered it by v. The piston in the main cylinder C is at the right-hand end of
its stroke, and the slide B is in such a position as to close the port e¹ without
opening . Ignition of the inflammable mixture is caused to take place by means
of any known apparatus suitable for the purpose, which being no part of my
present Invention is not shewn in the Figure. Immediately after this the slide Bis
moved towards the left so as to open the port e¹, from which there is communication
to the port a. The port e¹ is thus opened gradually so as to prevent shock to the
piston in the main cylinder C, and the shock may be further reduced by providing
a space for cushion therein. The products of coinbustion enter the cylinder C and
act on its piston, urging it towards the left. After the piston in the main cylinder
has performed a certain portion of its stroke the valve S is opened by the engine
and the compressed air or elastic fluid enters the cylinder A; it mixes with the fluid
in it, reducing its temperature, and passes with it to the main cylinder C, co-
operating with it in driving the piston. After a sufficient quantity of it has been
admitted the valve S is closed and communication with the reservoir of compressed
air cut off.
When it
The movement of the valve S may be varied in the manner of an expansion slide,
so as to vary the charge of air admitted as desired. The piston in the main cylinder
proceeds to the end of its stroke. During the period above .described the piston P
in the cylinder A remains stationary. The piston in the main cylinder now com-
mences its return stroke, the slide B being moved to the extreme of its stroko
towards the left, establishing communication between the ports e¹, a, and x, and
closing the port e. The piston P now makes its stroke from right to left, expelling
the elastic fluid in front of it through the eduction passage x, while it is followed
behind by a fresh charge of inflammable mixture, which enters by the valve v², and
which at the end of the stroke fills the cylinder A. Meanwhile, the piston in the
main cylinder is making its return stroke, driving out the exhaust products in its
cylinder through the body of the slide B and the eduction passage x.
attains the end of its stroke, the inflammable mixture is ignited, and the operations
previously described are repeated, the piston in the main cylinder making its stroke
again towards the left. When this stroke has been completed during the next return
stroke in the main cylinder, the operations previously described are repeated, the
valve v and the port e, performing the functions previously performed as described
by the valve and port e¹. And the piston P makes a stroke from left to right,
being followed by the inflammable mixture, which at the end of its stroke fills the
cylinder A. The position of the parts is now the same as that supposed at the com-
mencement of the description, and the cycle of operations is ready to be repeated.
The slide B and faces may be cooled by passage of cold water through ducts pro-
vided for the purpose. Also, instead of a single slide, separate slides or valves may
be employed to operate in the order described above.
When the engine is double-acting, apparatus such as above described is provided
at both ends of the cylinder.
In the construction above described the contents of the cylinder may either be
discharged into the atmosphere or into a refrigerator or chamber, kept cool by water
in any known manner, whence it is extracted by a pump or extracting apparatus.
The movement of the piston P in the charging cylinder may be effected by a cam
or other-suitable apparatus worked by the engine, or when a refrigerator kept at
low pressure is used as above mentioned, it may be worked by means of the pressure

page_text: of the entering charge of inflammable mixture. It may also be worked by means
of a subsidiary piston attached to it and working in a cylinder, which is connected
at suitable times with a chamber maintained by the engine, either at high or low
pressure.
pre-
Instead of employing a rectilineally moving piston as shewn in the Figure, a
rotary reciprocating piston might be employed. A construction generally similar
remains applicable when the requisite cooling is effected by means of water applied
externally and the use of compressed air is dispensed with. In this case the beat
imparted to the water may be utilised for the generation of steam as I have
viously mentioned. The steam so generated may be admitted by the valve Š in
lieu of the compressed air or otherwise; it may be admitted directly into the working
cylinder through a valve provided for the purpose; otherwise the steam may
perform work apart from the products. of combustion as previously noticed; in this
case it may work in a separate cylinder or engine, or the products of combustion
and the steam may work in the same cylinder on opposite sides of its piston, which
may be a differential one. When the steam is used conjointly with the products of
combustion, I prefer generally to cause the elastic fluid to act in two cylinders, a
high pressure and a low pressure one. The first of these is cooled by the water
casing, and within this the heat of the elastic fluid is reduced to a certain degree,
while it finishes its expansion in the second or low pressure cylinder, which is not
cooled by any external agency. The construction of engine remaining the same, the
steam employed may be generated by an independent source of heat, the water
casing being dispensed with; or as is obvious, steam generated in both ways may
be employed.
Fig. 2 shews a construction applicable when the products of combustion are
brought into direct contact with water, the steam generated from this passing along
with them into the main cylinder, and acting there in conjunction with them. In
this Figure A is the charging cylinder, and P, its piston; v, the valve for the
admission of the inflammable mixture; e, that for the outlet of the contents of the
cylinder A; B, the slide which controls the port u, forming a communication between
the main cylinder C and the evaporating chamber n, in which there is an evaporating
frame D, such as has been previously described; o, a passage leading from n to the
further end of the cylinder A; x, an eduction passage, which as well as the port u
is controlled by the slide B.
The operations take place as follows:-I suppose the piston P to be at the right-
hand end of its cylinder A, and this to be full of the inflammable mixture supplied
by the valve v. The slide B is in such a position as to close the ports u and a. The
mixture is ignited, upon which the pressure opens the valve e, and the products of
combustion pass from the cylinder A through the evaporating chamber n and the
passage o to the other side of the piston P, so that the pressure on this piston is
equalised. The slide B is moved by the engine opening the port u gradually so as
to avoid shock on the piston in the cylinder C; and elastic fluid consisting of cooled
products of combustion and steam enters that cylinder and urges its piston towards
the left. Simultaneously the piston P is moved by the engine towards the
left, driving in front products of combustion through the evaporating chamber n,
while the mixture of products of combustion and steam enter the cylinder A behind it.
The pistons proceed in this way to the ends of their strokes, at which period the
pressure in both cylinders is reduced to the lowest point desired. The slide B is
then moved towards the right by the engine so as to bring the port u in communi-
cation with x, and also to open x to the chamber n. The pistons then make their
return strokes, expelling the contents of both cylinders through the exhaust passage x,
while a fresh charge of inflammable mixture enters the cylinder A to the left of the
piston P through the valve v. During this movement the evaporating frame D is
lowered by the engine into the water and again raised. When the pistons have
completed their return strokes, the cycle of operations is ready to be repeated. When
the engine is double acting, apparatus such as above described is provided at both

page_text: ends of the main cylinder. The contents of the cylinders A and C may either be dis-
charged into the atmosphere or into a refrigerator or chamber kept cool by water in
any known manner, whence the fluid is extracted by a pump or extracting apparatus.
In the construction above described, if the evaporating chamber is omitted, the
remainder may be used in connection with the other means of effecting the cooling
previously described. For example, if compressed air is used for this purpose the
products of combustion issuing from the cylinder A and the compressed cold air
may both be admitted into one passage leading to the main cylinder and com-
municating with the passage o. Thus as the piston P advances in the cylinder A,
expelling the products of combustion from the one end of it, a mixture of these
products with cold air passes by o to the other end of the cylinder A and fills the
space behind the advancing piston P, while at the same time the cooled mixture
propels the piston in the main cylinder C. If the cooling is effected by means of
water enveloping the cylinders the same general construction may be retained, the
steam generated from the said water being admitted, as above described, with
reference to the cold air. If desired the piston in the charging cylinder may be
connected directly with that in the main cylinder.
In the Figure I have represented the piston in the charging cylinder as working
rectilineally, but a rotary reciprocating piston may be employed, and the piston
need in no case fit very tightly, as its function is merely to displace the fluid
contents of the cylinder with the same pressure on both sides during its movement.
The piston of the charging cylinder instead of being worked from the engine may
be detached from it, and worked by means of a subsidiary piston, as described in'
reference to Fig. 1.
Fig. 3 is a longitudinal section, Fig. 4, a transverse section, and Fig. 5, a sectional
plan of a construction in which the charging and working cylinders are placed
vertically; here A is the charging cylinder, and Pits piston. This cylinder is
provided with a slide v which may be of the known kind employed in gas engines
for the supply and ignition of the inflammable gaseous mixture. The upper part
of the cylinder A communicates by a valve e and pipe B with the lower part n,"
which serves as a cooling chamber having within it a reciprocating evaporating
frame D that dips in water W.. From the cylinder A there is a passage E to the
jacket of a slide S, governing the ports to each end of the working cylinder C and
to an eduction passage x.
:
The operations take place as follows:-The piston P and the working piston c. being
both at the lower end of their respective strokes, as shewn in Fig. 3, and the
cylinder A above P being charged with inflammable mixture; this is ignited,
whereupon products of combustion passing the valve e flow by the passage B into
the cooling chamber n, and rise through the evaporative frame D, generating steam
and becoming cooled. The slide. S gradually opening the lower port of the
cylinder C, the mixture of steam with products of combustion flowing by the pipe E
propels the piston c upwards, and by the ascent of this piston the contents of the
cylinder C above it are expelled by the eduction passage x; while the piston c
ascends, the charging piston P also ascends, displacing the contents of the cylinder A
above it, and the frame D descends into the water W. As the piston c approaches
the end of its up stroke the slide S is moved so as to place the lower port of the
cylinder C in communication with the exhaust. The pistons P and c then descend,
the former drawing into the cylinder A a fresh charge of inflammable mixture and
the latter expelling the exhaust, and the frame D having been wetted by its
immersion ascends to the position shewn in Fig. 3, whereupon the cycle of operations
above described is repeated.
Fig. 6 represents a vertical section of a construction wherein the working
cylinder C is double acting, and two charging cylinders a¹, a², fitted with
pistons p, p, are employed, one for each end of the cylinder. Each of the charging.
cylinders a, a, has a slide v¹, v³, for the admission and ignition of inflammable
mixture, and communicates by a pipe el, e², with a boiler or generator B. containing
water. On each of the pipes e¹, e2, is a valve which prevents water from entering

page_text: the pipe, and in the boiler B there is a screen b, of wire gauze or perforated metal, or
several such screens above the level of the valves. The upper end of the cylinder a¹
has a port governed by a slide s¹, which also governs two other ports, the one
communicating by a pipe f¹ with the bottom of the cylinder C and the other with
an eduction passage x¹. The other charging cylinder a² has likewise a slide 8²
similarly arranged, but one of the ports governed by it communicates by a pipe f
with the upper end of the cylinder C. The working piston P is connected in the
usual way to a crank shaft, which by means of cams or suitable gear, works the
pistons p, p, and the slides 81, 82, of the charging cylinders in time, properly
according with the movements of the main piston P.
In order to explain the operation of the apparatus, I will first describe the action
with reference only to one of the charging cylinders a¹. I will suppose p¹ the
piston of this charging cylinder to be at the lower end of its cylinder, and P the
piston of the main cylinder to be at the upper end of its cylinder. The piston p
of the charging cylinder ascends, driving out the elastic fluid above it through the
eduction port, while behind it is followed by a charge of inflammable mixture,
which at the end of the stroke fills the cylinder a¹. The slide s¹ is then moved so
as.to close the communication between the charging cylinder a¹ and the eduction
port x, and to open communication between its upper end and the generator B:-
The charge of inflammable mixture in the cylinder a is then ignited. The piston p¹
descends, driving the products of combustion beneath it into the generator B, while
elastic fluid from the generator enters the cylinder a² on its upper side. At the
end of the stroke the products of combustion are driven entirely into the generator B;
while the cylinder a¹ is filled above the piston with the elastic fluid from the
generator. These two strokes of the piston p¹ are made while the piston P of the
main cylinder is making its down stroke, during which it drives the elastic fluid
beneath it through the eduction port ¹. The slide 8 is now moved so as to open
communication between the upper end of the charging cylinder a and the pipe f¹,
leading to the bottom of the main cylinder C. The elastic fluid in the charging
cylinder a expands and acts upon the lower side of the main piston P, propelling it
upwards. During this period the pipe e¹ is closed by its self-acting valve, while
the elastic fluid in the charging cylinder is expanding and propelling upwards the
main piston P, the piston of the charging cylinder a¹ remains at rest. The piston P
having completed its up stroke the slide s¹ is moved, so as to open communication
between the pipe f¹ and the exhaust, and also between the charging cylinder a¹ and
the exhaust.
The above description bas explained the operations performed by the charging
cylinder a¹ in reference to the main cylinder C. Similar operations are performed
in respect to the other charging cylinder a², but differently timed." At the
stage of operations now reached, according to the above description, this cylinder is
filled with elastic fluid from the generator B. The slide s² is moved so as to open
communication between this and the top of the main cylinder C, and the expansion
of this fluid propels the piston P downwards. At the end of its down stroke the
slide 8 is moved so as to open communication between the pipe f2 and the exhaust,
and also between the charging cylinder a² and the exhaust. The stage of operations
which I suppose to exist at starting is now reached and the cycle of operations is
ready to be repeated.
In the above description the pistons p¹, p², of the charging cylinders have been
stated to remain at rest, while the elastic fluid in those cylinders expands into the
main cylinder and propels its piston; but these pistons might move, making an
up stroke and down stroke during this part of the operation, without performance of
work. If it is desired to operate in this manner a passage is provided to each
cylinder, so that the piston in each cylinder when the valve is opened simply
causes displacement of the elastic fluid from one end of its cylinder to the other.
Other parts of the construction remaining the same, the construction of the
generator may be altered.
i
Instead of passing the products of combustion through the water as above

page_text: described, they may be passed through flues or tubes surrounded by the water, so
as to issue from these into the upper part of the generator, where they mingle
with the steam produced.
One arrangement of this kind is shewn in Fig. 6, representing a longitudinal
section of a generator, in which horizontal tubes are used for the passage of the
products of combustion. In this case the pipes el, e³, leading from the charging
cylinders are provided with valves kept up by springs, and communicate with a
central cavity H, whence tubes I, I, surrounded by water extend each way to spaces
K, K, in the generator open to the upper part. The hot products of combustion issuing
from the pipe el or e² are cooled in passing through the tubes I, I, and
generate steain, which mingles with them in the upper space of the generator.
The charging cylinders a', a³, may be placed in the generator, and surrounded with
water.
The construction of engine above described is also applicable when the cooling of
the products of combustion is effected by means of air. In this case the vessel B is
supplied with air, which may be forced into it at any desired pressure by a pump
driven by the engine, as has been previously explained. The products of com-
bustion entering the vessel B become cooled by admixture with the air contained
therein, and the mixture acts in the same way in working the engine as the mixture
of products of combustion with steam, as above described.
The methods of working, above described, are obviously applicable not merely to
a single cylinder, as shewn in the Figures, but to various arrangements of multiple
cylinders, such as are used with steam engines. In all the above construc-
tions the inflammable mixture may be admitted into the charging cylinder at
or near the atmospheric pressure; but otherwise it may be introduced into it at
high pressure, its pressure being further raised by its ignition. It may be raised
to high pressure by means of pumps or forcing apparatus worked by the engine,
or it may issue from vessels or reservoirs in which it is contained at high pressure.
When the ingredients of the inflammable mixture issue from reservoirs in which
they are contained at high pressure the use of the charging cylinder may be dis-
pensed with, its place being supplied by governors.
Fig. 7 shews a construction of this kind. A and B are reservoirs of compressed
oxygen and gas; C, a reservoir of compressed air or elastic fluid; G1, G2, G3, arè
governors. The oxygen and gas issue into the chamber D, in which they undergo
combustion. Compressed air issues by the governor G³, and flows through the
passage o; it meets the stream of products flowing through the passage n out of
the combustion chamber D, and these two streams mix in the passage F of varying
area; the temperature of the products of combustion being thus reduced to the
degree desired, the mixed fluid passes on to work the engine.
It is obvious that air or nitrous oxide might be used instead of oxygen. When
air is thus employed two reservoirs are sufficient, one for the gas and one for the
air. The air issues from its reservoir in two streams, one of which passes to the
combustion chamber in which it undergoes combustion with the gas, while the
other portion issues into a passage or chamber beyond the combustion chamber,
mixing therein with the products of combustion, and cooling them to the degree
desired.
Fig. 8 represents a construction of this kind. Here A is the reservoir containing
the air, having two outlets regulated by governors G³ and G³, and B is the reservoir
containing the combustible gas, having an outlet regulated by the governor G².
The gas issuing by the orifice o mingles with a portion of the air from G¹ in the
mixing passage m, and meeting with another portion of the air, burns with it in
the combustion chamber C. The products of combustion issuing from C become
mixed with air from G³, and being cooled thereby pass by the pipe P to the engine.
Instead of making them pass directly to the engine I prefer to make them pass to
it through an accumulator into which they flow continuously, so that the combus-
tion is continuously maintained; v, v, are cocks or valves regulating the flow in
the several pipes. Constructions of a similar nature in which the cooling of the:

page_text: .
products of combustion is effected by bringing them into contact with liquid, which
they convert into vapour, have been described by me in the Specification of a
Patent granted to me on the 31st May 1876, No. 2288.
When the products are supplied in this manner an apparatus, such as shewn in
Fig. 9, may be employed. Here A is a vessel containing the liquid, which is sup-
plied by a feed pump or injector. The hot products of combustion pass down the
tube d into the branches o, o, which have numerous holes i, i; b, b, are perforated
plates or gratings, or sheets of wire gauze. The products of combustion issue from
o through the orifices i, i, and ascend through the liquid passing through the
orifices in the perforated metal b, b, generating vapour in their course. The mixed
products and vapour pass away by the passage e to be utilised as desired. Before
passing away the mixed fluid may be caused to pass through asbestos or porous
material.
I have mentioned above that the cooling of the products of combustion may be
effected entirely by passage of their heat through the cylinder to the water in
contact with them externally.
Fig. 10 shews a construction applicable when this method of cooling is employed,
being a modification of the construction shewn in Fig. 1. In this case the charging
cylinder A, B, piston P, supply valves v¹, v², ports e¹, e², slide B, and eduction
passage x, the working cylinder C, and its porta are similar in construction and
operation to the corresponding parts described above with reference to Fig. 1. I dis-
pense with the cold air valve S formerly described. Apparatus for ignition of the
inflammable gaseous mixture is provided, but, as explained in reference to Fig. 1,
is not shewn in the Figure. I enclose the cylinders A and C within the vessel D,
which acts as a boiler, steam being generated therein by the heat which passes
through the sides of the cylinders to the water contained in it. The level of the
water may be varied as desired, so as to keep more or less of the cylinder C
immersed therein. I provide a passage F, forming communication from the cylinder
port a to the upper part or steam space of the boiler D, and I fit that passage with
a valve f, or it may be a slide worked by the engine, so as to open or close the
the passage F during any desired part of the stroke of the main piston..
The operation is as follows:-The piston of the charging cylinder acts as described
in reference to Fig. 1, and the charge of imflammable mixture is admitted by
passage u and ignited. The valve f is opened and a portion of steam is admitted
from the boiler D into the main cylinder C. This expands within the main
cylinder until its pressure becomes equal to that of the products of combustion in
the charging cylinder, whereupon the valve f is closed and the valve B is opened.
Products of combustion from the charging cylinder enter the main cylinder, mixing
with the steam therein, and the mixed fluid expands, performing work.
Before the water in the boiler D has become sufficiently heated to generate steam
at the required pressure, the valve f may be kept closed, the engine then being
worked by the products of combustion alone. It is to be understood that when
the engine is double acting a charging cylinder and the apparatus connected with
it is employed for each end of the main cylinder, as already described with reference
to the construction shewn in Fig. 1; otherwise retaining generally the construction
shewn in Fig. 10 a single charging cylinder may be used for supplying the main
cylinder at its one end, and the steam generated in the boiler D may be employed
to supply it at its other end. For this purpose the passage F and its valve are
dispensed with, and a steam valve or slide is fitted at the other end of the working
cylinder. The forward stroke of the working piston is thus effected by the pressure
of the products of combustion, and the back stroke is effected by the pressure of
the steam generated in the boiler D; as the volume of steam thus generated may
be considerably less than that of the products of combustion, a differential working
piston may in this case be employed.
It has been mentioned above that the charge of inflammable mixture may be 5
supplied to the charging cylinder at high pressure, and that this may be done from
reservoirs. When reservoirs are employed for this purpose, the passages which

page_text: admit the inflammable mixture or its ingredients into the charging cylinder are
provided with governors, so that while the pressure in the reservoirs declines, the
pressure of the inflammable mixtures entering the charging cylinder remains
constant. When the inflammable mixture is thus supplied from reservoirs, I prefer
to employ oxygen instead of air as one of its ingredients. When the combustible
mixture is thus admitted into the charging cylinder at high pressure, I prefer still
so to arrange the construction and operation of the engine that the pressures on
both sides of the charging piston P shall always be nearly equal, as described with
reference to the preceding constructions. For this purpose, instead of delivering the
exhaust by the port x into the atmosphere, I deliver it into an accumulator
maintained at a pressure nearly equal to that of the combustible mixture that
enters the charging cylinder as regulated by the governors. This accumulator
supplies a separate cylinder, which may be single or double acting, the communication
between the accumulator and the cistern being controlled in the usual way by a
slide or valves worked by the engine. At each stroke a portion of the fluid in the
accumulator is admitted to this cylinder, wherein it expands, performing work, and
whence it is discharged as exhaust.
The construction above described remains applicable when the products of com-
bustion instead of being applied to generate steam or vapour are cooled by admixture
with cold air as has been previously mentioned. In this case it is preferable
to employ air instead of oxygen as one of the ingredients of the combustible
material.
Fig. 11 represents a vertical section of an engine operating as described with
reference to Fig. 10, the working cylinder being in this case vertical and fitted with
a differential piston, so that the down stroke is effected by the pressure of steam in
the boiler D, for which purpose a separate steam slide S is provided at the upper
end of the cylinder. The charging piston is here shewn to be worked by a cam E,
on a vertical shaft driven by bevil gearing F at half the speed of the crank shaft G.
The slide B is in like manner driven by a came on the same shaft.
Fig. 12 represents by a diagrammatic vertical section an arrangement of double
acting engine with two charging cylinders, the pistons of which are directly
connected to and work in time with the main piston; A1 and A2 are the two
charging cylinders and P1, P2, their pistons; C is the main cylinder and B its piston.
The three piston rods are connected to one cross head E, so that all the pistons
perform their strokes simultaneously. The cylinder A¹ is fitted at its lower end
with a slide S¹, governing a port leading to the bottom of the cylinder, and a port
leading to a side passage f¹, which is connected by a pipe to a corresponding side
passage g near the upper end of the cylinder C. There is also a passage a¹ to the
upper end of the cylinder A¹, which is always open to the casing of the slide S
and to the passage f¹. The cylinder A2 is fitted at its upper end with a slide S²,
governing passages similar to those governed by S¹, but their arrangement is
inverted, and the side passage f in this case communicates by a pipe with a side
passage g near the lower end of the cylinder C. At the upper end of the cylinder C
there is a slide T governing three ports, one leading to the top of the cylinder C,
one leading to the side passage g¹ that communicates with f¹, and one leading to
another side passage h¹ for exhaust. In like manner the lower end of the cylinder C
has a slide T governing corresponding passages in an inverted position.
The several slides are supposed to be worked by cams or other suitable gear, timing
their movement to suit the operation of the engine, as I will presently describe. The
two cylinders A1, A2 and the lower part of the cylinder C are enclosed within a
strong vessel D which acts as a boiler having water or other suitable liquid supplied
to it by a feed pump, the charging cylinders A1, A2, being always submerged, and a
space for steam or vapour being left in the upper part of the boiler. From this space
there are passages into the casings of the slides T2 and T. It is to be understood
that each of the cylinders A1, A2, is provided with a slide or valves for the admission
and ignition of the combustible charge. The pistons are in Fig. 12, shewn at half
stroke, descending..

page_text: In describing the operation of the engine I will suppose them to be at the tops of
their respective cylinders, that the cylinder A¹ is filled under its piston with a charge
of the combustible gaseous mixture, that the cylinder A2 and the cylinder C both
contain fluid which has expanded, performing work in the latter, and is ready to be
discharged as exhaust. The slide $¹ ascends uncovering the port at the bottom of
A, and T¹ descends, admitting a limited quantity of steam from its casing, supplied
from the boiler D into the cylinder C above its piston, which begins to descend, the
slide T¹ ascending. At this time or shortly afterwards, the charge in A¹ is ignited,
and, there being free communication between the two ends of the cylinder, its piston
P remains in balance or nearly so. The slide T¹ ascends, opening the port of g¹ to
the top port of the cylinder C. Products of the combustion in A¹ flowing by f¹ and
y are thus supplied to the upper end of the cylinder C, and expand therein along
with the steam previously admitted, propelling the piston B downwards. In thus
admitting the products of combustion to the cylinder C the slide T¹ gradually opens
its ports so as to avoid shock to the engine. While the pistons descend, the slide T²
is in such a position as to open the port from the bottom of the cylinder C and also
that from 2 to the exhaust passage h², and the slide S² covers the port leading to
the top of the cylinder A², leaving f2 open. By the descent of the pistons B and P²
the expanded fluid under them is driven out by the exhaust passage h³, and the piston
P² draws into the cylinder A2 above it a charge of combustible mixture. When the
pistons have reached the bottom of their stroke, the cylinders A¹ and C being filled
above their pistons with expanded fluid, and the cylinder A² being charged above
its piston with combustible mixture, the slides T2 and S2 now act for the up stroke,
supplying the cylinder C below its piston as T¹ and S¹ acted for the downstroke, and
T and S¹ now act for the discharge of exhaust from above the pistons B and P¹ in
their up stroke, as T3 and S2 acted for the discharge of exhaust below Band P2 during
the down stroke. When the up stroke is completed the cycle of operations above
described is repeated.
When engines are used for locomotion on streets or roads, the presence of
steam in the discharged exhaust is considered in some cases objectionable and the
radiation of heat from a steam boiler is sometimes inconvenient. Both these incon-
veniences may be avoided by employing liquefied gas, such as carbonic anhydride,
as the liquid to be converted into vapour by the heat abstracted from the products
of combustion. The various constructions above described may be modified by
employing multiple cylinders or successive cylinders for working expansively.
The steam or vapour when used separately from the products of combustion may
be exhausted into a condenser and the steam or vapour and products of com-
bustion when used together may be exhausted into a refrigerator or vessel kept
at low pressure.
Having thus described the nature of my Invention and in what manner the same
is to be performed, I claim in respect of engines worked by products of combustion of
a gaseous inflammable mixture,―
First. The use of a separate charging cylinder immersed in water or liquid whence
by the heat of the combustion within the said cylinder vapour is generated which
co-operates with the products of combustion, substantially as herein described.
Second. So arranging the valves and passages connected with the separate charging
cylinder that its piston always works nearly in balance, or with pressures nearly
equal on both its sides, substantially as herein described.
Third. The construction of engine worked partly by the cooled products of the
combustion of an inflammable gaseous mixture and partly by steam or vapour
generated in cooling the said products, substantially as herein described with reference
to Fig. 2 of the accompanying Drawings,
Fourth. The construction of engine worked partly by the cooled products of the
combustion of an inflammable gaseous mixture and partly by steam or vapour gen-
erated in cooling the said products, substantially as herein described with reference
to Figs. 3, 4, and 5.
Fifth. The construction of engine worked partly by the cooled products of the

page_text: combustion of an inflammable gaseous mixture and partly by steain or vapour gen-
erated in cooling the said products, substantially as herein described with reference
to Figs. 6 and 64.
Sixth. The construction of engine worked partly by the cooled products of the
combustion of an inflammable gaseous mixture and partly by steam or vapour gen-
erated in cooling the said products, substantially as herein described with reference
to Fig. 10.
Seventh. The construction of engine worked partly by the cooled products of the
combustion of an inflammable gaseous mixture and partly by steam or vapour gen-
erated in cooling the said products, substantially as herein described with reference
to Fig. 11.
Eighth. The construction of engine worked partly by the cooled products of the
combustion of an inflammable gaseous mixture and partly by steam or vapour gen-
erated in cooling the said products, substantially as lierein described with reference
to Fig. 12.
And, lastly. I claim, producing fluid for working an engine by burning in a
combustion chamber gases or elastic fluids supplied under regulated pressure from
reservoirs, and mingling the products of their combustion with cool air or elastic
fluid which is also supplied under regulated pressure, substantially as herein
described.
In witness whereof, I, the said Matthew Piers Watt Boulton, have hereunto set
my hand and seal, this Twenty-eighth day of July, in the year of our Lord
One thousand eight hundred and seventy-seven.
M. P. W. BOULTON. (L.S.)