IMPROVEMENTS IN GAS ENGINES
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by the said William Foulis at the Office
of the Commissioners of Patents on the 15th June 1880.
WILLIAM FOULIS, of Glasgow, in the County of Lanark, North Britain, Civil
Engineer. "IMPROVEMENTS IN GAS ENGINES."
This Invention, which relates to improvements in gas engines, consists as
follows:-
Firstly. In so constructing that part of the cylinders of such engines in which
the heat of the explosion of the mixture of gas and air is developed, that whilst
such part of the said cylinders is maintained as hot as is practicable, the other part
of the said cylinders, namely, that in which the piston works, becomes heated to
a very much less extent.
This is effected by constructing such cylinder in two portions, namely, that in
which the closely fitting piston acts, and another portion in which the heat and
pressure due to the explosion is developed. These two parts are united together
by flanches and bolts, but a thick layer of asbestos, millboard, or equivalent non-
conducting material, is placed between the flanches so as, as much as possible, to
prevent the communication of heat from the hottest part of the cylinder by
conduction to the other part; or in place of making the said cylinder in two parts
it may be made in one piece, the one part being kept hot by lining it with fire clay
or other similar material, and the other part being kept cool by a water casing or
otherwise.
For the sake of facility in describing these improvements it is hereinafter assumed
that the cylinders are vertical, and the two parts of which they are constituted aro
referred to as the upper and lower parts respectively.
The upper part of the cylinder is lined with asbestos or other nonconducting
materials, and the piston, the upper part of which is covered with fire-clay or
equivalent material, carries a tubular projecting piece of nearly the same diameter
as the inside of the cylinder, and of nearly the same length. This projecting

page_text: piece is or may be also encased or lined with asbestos or other conducting
material.
Secondly. To prevent interference by the foul gas which is contained, more or
less compressed, in the upper part of the cylinder with the complete combustion of
the gascous mixture by which the engine is driven, the upper part of the cylinder
is provided with a separate combustion chamber of suitable proportion, and from
the centre of the piston there projects upwards a secondary piston of nearly the
same diameter as the boro of this combustion chamber. Both the combustion
chamber and the piston which passes into and out of it may be covered with asbestos
or other nonconducting material, but do not fit tight to each other in order to
prevent abrasion or destruction by friction of the surfaces, which would take place
if they worked in contact; or the combustion chamber may be fitted with a piston
not attached to the piston of the engine, but which is or may be operated by the
piston or other movable part of the engine.
The mixture of air and gas is forced into and ignited in this chamber by the
means hereinafter described under the third head of the present improvements.
The gaseous mixture is forced into the combustion chamber until the piston in
that chamber has arrived at the position of tho stroke whereat combustion or
explosion takes place, so that the combustion of the whole of it takes place,
whilst it is prevented by the aforesaid piston from mixing with the foul gases.
Thirdly. To ensure the proper ignition of the gas and air the igniter described in
the Specification of me, the said William Foulis, No. 4843, A.D. 1878, and which is
placed in the upper part of the combustion chamber, is or may be surrounded with
a perforated shield, through which and across the surface of the igniter the air and
gas are forced until the instant for the explosion arrives. At this instant the
motion or flow of the air and gas is stopped, and its ignition takes place; or instead
of this arrangement the igniter may be surrounded by a movable casing, which
exposes it in at the instant the combustion of the gas and air is required to
take place. Fourthly. For the purpose of mixing the air and gas in the proper
proportions necessary for their complete combustion, an apparatus is provided
consisting of a flexible chamber, to which a pipe is connected from the cylinder or
cylinders of the engine. This chamber is loaded by a weight or spring so as to
maintain in it a constant pull against the exhausting influence upon it of the
piston in the cylinder. The flexible chamber is provided with two ports, one for
the admission of air and the other for gas, these ports being again provided with
slides, stop cocks, or equivalent means for regulating from time to time the area of
admission for both the gas and air. A valve is placed at that part of the apparatus
whereat the air and gas ports are united, and the weight or spring acting on the
flexible chamber keeps this valve shut at all times when the air and gas are not
flowing into the chamber, but when the exhausting effect due to the motion of the
pistons reduces the pressure therein then the weight is lifted, so that the valve is
raised from its seat, thereby admitting a further supply of gas and air. By this
arrangement a reservoir of properly mixed air and gas is at all times maintained,
from which the engine when in operation draws off the quantity required. A self
acting valve or clack may be placed between each cylinder and the flexible
chamber.
The flexible chamber may, however, be dispensed with by connecting the pipes
leading from the self acting valve chamber of each cylinder to a reservoir containing
gas and to the atmosphere, the pipes being provided with adjustable orifices for
admitting the proportion of gas and air proper for complete combustion.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Foulis in the Great Seal Patent Office on the 15th December
1880.
WILLIAM FOULIS, of Glasgow, in the County of Lanark, North Britain, Civil
Engineer. "IMPROVEMENTS IN GAS ENGINES."
My said Invention relates to improvements in gas engines, and consists as
follows:-
Firstly. In constructing the cylinders of such engines so that whilst the part in
which the heat of the combustion of the mixture of gas and air is developed is
maintained as hot as practicable, the other part of the said cylinders, namely, that
in which the piston works, becomes heated to a very much less extent.
This is effected by constructing such cylinders in two portions, namely, that in
which the closely fitting piston acts, and another portion in which the combustion
is developed. These two parts are each of about the same length, and are united
together by flanches and bolts, but a thick layer of asbestos, millboard, or equivalent
non-conducting material is placed between the flanches so as, as much as possible,
to prevent the communication of heat from the hottest part of the cylinder by
conduction to the other part.
The hottest part of the cylinder is or may be lined with asbestos or other non-
conducting material, and the side of the piston which is presented towards this
part of the cylinder is covered with asbestos, or fireclay, or equivalent material.
This side of the piston also carries a tubular piece of nearly the same diameter as
the inside of the cylinder, and of nearly the same length as either part of the said
cylinder, the said tubular pieco being separated from the piston by the aforesaid
layer of asbestos or equivalent material. This projecting pieco is encased or lined
with asbestos or other non-conducting refractory material.
Secondly. To prevent interference of the foul gas (which is contained, moro or
less compressed, in the combustion part of the cylinder) with the complete combustion
of the gaseous mixture by which the engine is driven, the said part of the cylinder
is provided with a separato combustion chamber, and from the centre of the driving
piston there projects a piston of nearly the same diameter as the bore of this
combustion chamber, but they do not fit tight to each other, so that abrasion or
destruction by friction of the surfaces which would take place if they worked in
contact is prevented.
The mixture of air and gas is forced into this chamber and then ignited by the
means hereinafter described under the third head of the present improvements. The
gaseous mixture is forced into the combustion chamber until the piston in that
chamber has arrived at the position of the stroke whereat combustion or explosion
takes place, so that the combustion of the whole of it takes place whilst it is
prevented by the aforesaid piston from mixing freely with the foul gases.
Thirdly. To ensure the proper ignition of the gas and air the igniter described in
the Specification of Letters Patent, No. 4843, granted to me, the said William
Foulis, as of the 28th day of November, A.D. 1878, is placed in communication with
the combustion chamber, and is surrounded by a moveable casing, which exposes
it at the instant the combustion of the gas and air is required to take place.
Fourthly. For the purpose of mixing the air and gas in the proper proportions
necessary for their complete combustion, an apparatus is provided consisting of a
flexible chamber, to which a pipe is connected from the cylinder or cylinders of the
engine or pump. This chamber is loaded by a weight or spring so as to maintain
in it a constant pull against the exhausting influence upon it of the piston or
pistons in the cylinder or cylinders. The flexible chamber is provided with two

page_text: ports, one for the admission of air and the other for the admission of gas, these
ports being provided with slides, stop cocks, or equivalent means for regulating
from time to time the area of admission for both the gas and air. A valve is placed
at that part of the apparatus whereat the air and gas ports are united, and the
weight or spring acting on the flexible chamber keeps this valve shut at all times
when the air and gas are not flowing into the chamber, but when the exhausting
effect due to the motion of the pistons reduces the pressure in the said flexiblo
chamber then the weight is lifted, so that the valve is raised from its seat, thereby
admitting a further supply of gas and air; the said valve is furnished with a lip or
rim, which will prevent the gas and air gaining admission to the chamber until the
valve has lifted to a sufficient extent to prevent the pressure of the gas interfering
with the just proportions of the air and gas. By this arrangement a roservoir of
properly mixed air and gas is at all times maintained, from which the engine when
in operation draws off the quantity required. A self acting valve or clack is placed
between each cylinder and the flexible chamber.
And in order that my said Invention may be properly understood, I now proceed
more particularly to set forth the system, mode, or manner in or under which the
same is or may be used or practically carried into effect, reference being had to the
accompanying Drawing and to the letters and figures marked thereon, that is to
say:―
I will describe the first part of my Invention with reference to Figure 1 of the
accompanying Drawings, which is a longitudinal section of a cylinder of a gas
engine provided with means for carrying this part of my invention into effect. The
cylinder is made in two portions A and B, the portion A being that which contains
the chamber wherein the combustion of the gaseous mixture takes place, and the
portion B being that in which the piston d works. These portions are united
together by bolts, not shewn in the Drawing, passing through the adjacent flanches
of the said parts, a layer (preferably a thick layer) c of asbestos, millboard, or
equivalent non-conducting refractory material being placed between the said
flanches so as to prevent as much as possible the communication of heat from the
portion A to the portion B. The part B is cooled by a water casing b, through
which a flow of water or other cooling medium is maintained. The part A of the
cylinder is or may be lined or coated with asbestos or other non-conducting
refractory material, and the piston d has a layer of asbestos or fire-clay or
equivalent material at its back. The said piston carries a projecting tubular piece 6,
of nearly the same external diameter as the inside of the cylinder, and nearly of the
same length as either portion of the cylinder, the said piece e being lined with
asbestos or other non-conducting refractory material. The layer 2 is preferably
between the piston and the tubular piece c, and it may be continued to some
distance inside the piece e.
To prevent as far as possible the interference of the foul gas (which is contained,
more or less compressed, in the part A) with the complete combustion of the gaseous
mixture by which the engine is driven, the said part A is provided with a com-
bustion chamber f, and from the centre of the piston & there projects a piston g,
of nearly the same diameter as the interior of the chamber f. The piston g may be
covered with asbestos or other non-conducting refractory material. The gaseous
mixture is forced into the combustion chamber, and is prevented by the piston g
from mixing freely with the foul guses. In commencing to work the engine the gas
and air are ignited by the igniter A, described in the aforesaid Specification of my
Patent, No. 4843, A.D. 1878. I have found that it is desirable to delay the ignition
of the gases by the igniter until all the gas and air compressed at each stroke of the
pump has been forced into the combustion chamber. In order to delay the ignition
until this has been effected, the piston g carries a sleeve or cover i, which encloses
the igniter during this period of delay. Figure 2 is an enlarged view of the end of
the cylinder and the igniter shewing the sleeve i enclosing the igniter, and also shewing
the piston g in the chamber in the positions they assume at the end of the back
stroko of the piston d.

page_text: In lieu of placing the combustion chamber finside the portion A, as hereinbefore
described, the combustion chamber may be situated at the outer side of the cover A³
of the said part A, thereby forming an extension of the said chamber. An admission
valve is, of course, employed in the inlet pipe between the pump and the cylinder.
Figure 3 represents in sectional elevation, and Figure 4 in sectional plan, the
arrangement for mixing the air and gas in the proper proportions necessary for their
complete combustion. A pipe:j leads from the cylinder or cylinders of the engine
or pump into a flexible chamber k, loaded by a weight or spring (as at 7), so as to
maintain in the said chamber a constant pull against the exhausting influence upon
it of the piston in the cylinder or cylinders or pump. The spindle, carrying the
weights L, also carries a valvo, having a lip m is the inlet for air, and n is the
inlet for gas, thoy being provided with shutters or cocks (as at 7) for regulating
the quantity of air or gas flowing through them. The weights keep the valve
closed at all times when the air and gas are not flowing into the chamber k (thus
automatically shutting off the flow of gas when the engine is stopped); but when
the exhausting effect due to the motion of the pistons reduces the pressure therein,
then the weight is lifted so that the valve. is raised from its seat, and the air and
gas are admitted to the said chamber. The lip prevents the gas and air gaining
admission to tho flexible chamber until the valve has risen to an extent sufficient
to prevent the pressure of gas from being unduly exerted.so.as to interfero with
the just proportion of air and gas as decided by the regulated admissions of the
inlets m and n. By this arrangement a reservoir of properly mixed air and gas is
at all times maintained, from 'which the engine, when in operation, draws off tho
quantity required.
1
Figures 5 and 6 represent in longitudinal and transverse sections respectively, a
valvo which may be used in place of the arrangement Figures 3 and 4. The air
inlet m and the gas, inlet naro both covered by a flap valve, and on the valvo
sent around the said valve is a rim 1, which will prevent the said valve allowing
air and gas to pass until it has opened sufficiently to prevent the injurious effect of
the gas pressure before referred to.
Gas engines constructed with the improvements hereinbefore described may be
placed horizontally, or vertically, or inclined, the stroke of the piston or pistons of
the cylinder or cylinders being necessarily to some extent in advance of the stroke
of the pump or pumps.
i
Having now described and particularly ascertained the nature of my snid
Invention, and the system, mode, or manner in or under which the same is or
may be used, or practically carried into effect, I would observo in conclusion that
what I consider to be novel and original, and therefore claim as the Invention
secured to me by the.herein before in part recited Letters Patent is,-
First. The construction of the cylinders of gas engines in two parts (A and B),
separated by a non-conducting material (c), whereby the greater heat of the part in
which the combustion takes place is prevented from being transmitted to the part
in which the piston works.
Second: Providing the pistons of gas engines with a tubular projecting piece (e),
lined with non-conducting refractory material for preventing the transmission of
heat to the portion (B) of the cylinder in which the piston works; also providing
the piston with a layer or covering (d²) of 'non-conducting refractory material for
the like purpose.
Third. The combination of a cylinder in two parts (A and B), separated by a
non-conducting refractory material (c), with a piston having at back a layer
of non-conducting refractory material, and carrying a tubular projecting piece (e),
lined with non-conducting refractory material, essentially as and for the purpose
•

page_text: until the piston has made a portion of its forward stroke, essentially as horeinbefore
described.
Sixth. The apparatus for effecting the mixing of gas and air in proper
proportions, hereinbefore described and illustrated in Figures 3, 4, 5, and 6 of the
accompanying Drawings, wherein the valve is provided with a lip (Figure 3), or a
rim (Figures 5 and 6), for preventing the passage of the gas and air until the
valve has risen sufficiently, for the purpose hereinbeforo described.
In witness whereof, I, the said William Foulis, have hereunto set my hand
and seal, this Thirteenth day of December, in the year of our Lord One
thousand eight hundred and eighty.
WILLIAM FOULIS. (L.S.)