IMPROVEMENTS IN COMBINED GAS AND STEAM MOTOR ENGINES
Year: 1878

page_text: LETTERS PATENT to Matthew Piers Watt Boulton, of Tew Park, in the County
of Oxford, for the Invention of "IMPROVEMENTS IN COMBINED GAS AND STEAM
MOTOR ENGINES."
Sealed the 6th September 1878, and dated the 6th July 1878.
:
PROVISIONAL SPECIFICATION left by the said Matthew Piers Watt Boulton
at the Office of the Commissioners of Patents on the 6th July 1878.
MATTHEW PIERS WATT BOULTON, of Tew Park, in the County of Oxford.
"IMPROVEMENTS IN COMBINED GAS AND STEAM MOTOR ENGINES."
This Invention relates to engines worked by products of combustion of an
inflammable mixture, and by steam or vapour performing work along with them.
In what follows I shall speak of gas and air as the ingredients used, it being under-
stood that what is said of them is applicable when other elastic fluids are employed.
Again, where I speak of the heat as generating steam from water, it will be under-
stood that other liquid might be converted into vapour, and this utilised in like manner.
I provide a vertical cylinder fitted with a piston. The lower end of the cylinder is
provided with apparatus for the introduction of gas and air at any pressure desired,
and for effecting combustion. The upper end of the cylinder contains or is in com-
munication with a considerable space, which constitutes a steam space as in a steam
boiler. The piston which works in the cylinder carries on its upper side a certain
quantity of water in contact with the interior surface of the cylinder, the supply of
this water being maintained by suitable feeding apparatus. The hot fluid which
follows the piston in its ascent heats the metal of the cylinder; on the return stroke
the descending piston brings the water in contact with the heated surface, and in
consequence steam is generated in the space above the piston; thus the pressure of
the steam space always acts on the upper side of the piston, while on its under side
there is in the up stroke the high pressure of the heated fluid, and in the down
stroke the low pressure of the fluid after performance of work.
In each up stroke immediately after the combustion a portion of steam is

page_text: admitted from the steam space into the lower end of the cylinder, becomes heated
by the hot gases and metal, and acts in the cylinder as working fluid.
I prefer to introduce the steam so that it passes in contact with the metal of the
cylinder in order better to abstract heat froin it.
Two cylinders may be provided, the up stroke in one being simultaneous with
the down stroke in the other.
Also one cylinder may be provided fitted with a differential piston, the upper side
of this, which is constantly acted on by the steam, being the side of smaller area.
In this case the engine may be rendered double acting with only one cylinder.
The number of cylinders with pistons, differential or other, may of course be
increased.
The fluid after its discharge from the cylinder still retains available heat. This
is utilised by causing it to pass through the tubes or passages of a boiler so as to
generate steam, which passes to the steam space previously mentioned, and assists
in working the engine.
By suitably arranged valves the contraction of the fluid as it becomes cooled in
the boiler flues may be utilised by reduction of pressure in the cylinder during the
piston's down stroke.
In addition to the method of cooling the cylinder previously described, external
cooling of the cylinder and its adjuncts may be used to such an extent as is
desired.
Before steam pressure is available for efficient working it is desirable to use a
larger quantity of gas and air in the cylinder. For this purpose means are pro-
vided by which the quantity of combustible charge introduced into the cylinder
can be increased or diminished, and the period of ignition can be suitably adjusted.
The apparatus for this purpose may for the ordinary working of the engine be put
under the control of a governor.
On first starting the engine the gas and air used may issue from receptacles in
which they have been previously compressed.
If it is desired to reduce rapidity of combustion of the gas and air this may be
done by Lenoir's method, viz., by introducing streams of gas between streams
of air.
The orifices of admission may conveniently be placed at the end of the cylinder,
and have an annular form.
The gas may be introduced mixed with some air or fluid to ensure its burning
smokelessly.
The following is another method:-The air and gas are mixed before entering
the cylinder, and are introduced into it in numerous streams. These streams are
differently proportioned. In one set of streams the rapidity of combustion is
reduced by excess of gas, in the other by excess of air. In this case also the
streams may conveniently be introduced at the end of the cylinder through orifices
disposed annularly.
Other things remaining the same the cylinder or cylinders of the engine may be
cooled by water externally, their internal cooling by means of water carried on the
piston or pistons being dispensed with. In such a case the cylinders may be
horizontal, or have any position.

page_text: 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 3rd January 1879.
MATTHEW PIERS WATT BOULTON, of Tew Park, in the County of Oxford.
"IMPROVEMENTS IN COMBINED GAS AND STEAM MOTOR ENGINES."
This Invention relates to engines worked by products of combustion of an
inflammable mixture, and by steam or vapour performing work along with them.
In what follows I shall speak of gas and air as the ingredients used, it being under-
stood that what is said of them is applicable when other elastic fluids are employed.
Again, where I speak of the heat as generating steam from water, it will be under-
stood that other liquid might be converted into vapour, and this utilised in like
manner.
I provide a vertical cylinder fitted with a piston. The lower end of the cylinder
is provided with apparatus for the introduction of gas and air at any pressure
desired, and for effecting combustion. The upper end of the cylinder contains or is
in communication with a considerable space, which constitutes a steam space as in
a steam boiler. The piston which works in the cylinder carries on its upper side a
certain quantity of water in contact with the interior surface of the cylinder, the
supply of this water being maintained by suitable feeding apparatus. The hot
fluid which follows the piston in its ascent heats the metal of the cylinder; on the
return stroke the descending piston brings the water in contact with the heated
surface, and in consequence steam is generated in the space above the piston. Thus
the pressure of the steam in the steam space always acts on the upper side of the
piston, while on its under side there is in the up stroke the high pressure of the
heated fluid, and in the down stroke the low pressure of the fluid after performance
of work.
In each up stroke, immediately after the combustion, a portion of steam is
admitted from the steam space into the lower end of the cylinder, becomes heated
by the hot gases and metal, and acts in the cylinder as working fluid.
I prefer to introduce the steam so that it passes in contact with the metal of the
cylinder, in order better to abstract heat from it.
Two cylinders may be provided, the up stroke in one being simultaneous with the
down stroke in the other."
Also one cylinder may be provided, fitted with a differential piston, the upper side
of this, which is constantly acted on by the steam, being the side of smaller area. In
this case the engine may be rendered double acting with only one cylinder.
The number of cylinders with pistons, differential or other, may of course be
increased.
The fluid after its discharge from the cylinder still retains available heat. This
is utilised by causing it to pass through the tubes or passages of a boiler so as to
generate steam, which passes to the steam space previously mentioned, and assists.
in working the engine.
By suitably arranged valves the contraction of the fluid as it becomes cooled in
the boiler flues may be utilised by reduction of pressure in the cylinder during the
piston's down stroke.
In addition to the method of cooling the cylinder previously described external
cooling of the cylinder and its adjuncts may be used to such an extent as is desired.
Before steam pressure is available for efficient working it is desirable to use a
larger quantity of gas and air in the cylinder. For this purpose means are pro-
vided by which the quantity of combustible charge introduced into the cylinder
can be increased or diminished, and the period of ignition can be suitably adjusted..
The apparatus for this purpose may for the ordinary working of the engine be put
under the control of a governor.
On first starting the engine the gas and air used may issue from receptacles in
which they have been previously compressed.
:

page_text: the cylinder, the piston, subject to the increased pressure resulting from the com-
bustion, continues to ascend.
At a determined part of its upward stroke the slide K moves so as to open the
port n, steam thereupon enters the cavity N and passes into the cylinder by the
slit or holes at the circumference in a current or numerous streams directed against
and along the interior surface of the cylinder, abstracting heat therefrom. The
products of combustion of the gaseous charge along with the steam admitted as
described now act on the piston C, driving it upwards through a portion of its
stroke, the slide K being again moved so as to close the port n, the supply of
steam is cut off and the remainder of the up stroke of the piston is effected
expansively..
It will be seen that during the up stroke there is a downward pressure, that of
the atmosphere acting on the area of the plunger D, and that of the steam in the
boiler acting on the annular area by which the piston C exceeds the plunger D.
This pressure acting above the piston in excess of the pressure of the expanded and
partially cooled fluid below it, causes the piston to make its down stroke, water
from the boiler following it down and abstracting heat from the interior surface
of the cylinder.
As the piston approaches the bottom of the cylinder the slide K moves so as to
put the port n in communication with the exhaust passage m by which the
contents of the cylinder under the descending piston are discharged. The piston
having reached the bottom of the cylinder the operation is repeated.
Fig. 2 represents a longitudinal section of an engine operating as described with
reference to Fig. 1, but arranged with its cylinder horizontal.
In this case the cylinder is placed entirely within the boiler, the water of which
has free access at the front end of the cylinder to its interior. The piston is made
of trunk form giving a differential area on its opposite sides. The other parts
are marked with the letters employed for indicating the corresponding parts in
Fig. 1.
Two engines operating as described may be connected to one crank shaft working
cranks set opposite to one another, in which. case the plunger or trunk of the
piston inay be dispensed with, the steam pressure on the two pistons being
balanced.
Fig. 3 represents a vertical section of an apparatus which may be employed to
effect the ignition of the combustible charge in the cylinder of an engine, such as I
have described, or of other gas-motor engines. S is a vessel in which there is a
flame T supplied with gas by the passage s, and with air by the passage s¹, both
these passages being fitted with spring check valves. The vessel also communicates
with the working cylinder of the engine by a passage s² governed by a slide. There
is also an outlet passage & fitted with a spring valve opening inwards, and at the
mouth of this passage a flame U is kept burning. When the cylinder is charged
with combustible mixture the slide is moved so as to open the passage 8², and the
flame T thereupon ignites the charge. The increase of pressure resulting from the
coinbustion of the charge causes the valves in the passages 8, 81, and 83, to close, the
internal flame T becoming extinguished. When the pressure in S becomes again
reduced to that of the atmosphere, the valves in 8, s', and 83 open, the vessel S
becomes charged with gas and air, a portion of which issuing by the passage 8³ is
ignited by the flame U, and the flame striking back lights again the flame T, which
is then ready to effect the ignition of the succeeding cylinder charge.
For the purpose of introducing into the cylinder a number of parallel streams of
air and gas mingled in different proportions, a rotating slide may be fitted at the
end of the cylinder, as shewn at Figs. 4, 5, and 6, Fig. 4 being part of a longitudinal
section of the cylinder, and its end, Fig. 5, a view of the interior face of the cylinder
cover, and Fig. 6, a section through the slide at Z, Z, of Fig. 4. According to the
arrangement shewn in these Figures a number of holes arranged annularly are
intended to give passage of gaseous mixture in which the gas is in excess, and
other holes u and v to give passage for mixture in which air is in excess of the

page_text: proper combustible proportions. The slide has cavities formed in it, one set of these
cavities being situated behind the other set. Of the hinder cavities the middle
one W receives gas alone by a pipe w, and the two side cavities receive air alone by
apertures x, x. The front cavities consist of a central space V having openings
which lead to the holes v, in annular cavity T leading to the holes t, and an outer
annular cavity U leading to the holes u. Each of these cavities communicates by
holes through the middle partition of the slide with the hinder cavities W and X,
and these holes are proportioned in their areas so as to give passage to the gas and
air in the desired proportions in each case. Thus U and V may have holes leading
from the air cavities X larger than those leading from the gas cavity W, so as to
receive excess of air, and T may have holes leading from W larger than those
leading from X, so as to receive excess of gas.
The slide is partly turned by a cam or other mechanism working its spindle Y to
the position shewn in Fig. 4, admitting the streams of gas and air mixture to the
cylinder. It is then rapidly turned a little so as to close the orifices t, u, v, at or
immediately before the charge in the cylinder is ignited, so as to prevent outflow
by these apertures.
Having thus described the nature of my Invention, and in what manner the
same is to be performed, I claim,―
First. Cooling the cylinder of a gas-motor engine, and utilising the heat abstracted
therefrom for the generation of steam by admitting water to the interior of the
cylinder on one side of the piston, substantially as herein described.
Second. In an engine in which the combustion of an inflammable gaseous mixture
is applied to produce motive power, employing in conjunction with the products of
the said combustion steam generated from water applied to cool the cylinder in the
manner referred to in the preceding claim, substantially as herein described.
Third. In a combined gas and steam motor engine the combination of the working
cylinder A and its piston and slides with the boiler B, constructed and operating
substantially in the manner and for the purposes herein set forth.
In witness whereof, I, the said Matthew Piers Watt Boulton, have hereunto
set my hand and seal, this 28th day of December, in the year of our Lord
One thousand eight hundred and seventy