IMPROVEMENTS IN GAS ENGINES
Year: 1881

page_text: LETTERS PATENT to William Foulis, of Glasgow, in the County of Lanark,
North Britain, Civil Engineer, for an Invention of "IMPROVEMENTS IN GAS
ENGINES."
PROVISIONAL SPECIFICATION left by the said William Foulis at the Office
of the Commissioners of Patents on the 14th January 1881.
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, has for its objects
the following:
Firstly. To so construct gas engines that the gaseous mixture is compressed in a
pump, from which it is allowed to flow directly into a cylinder of larger diameter
than the pump, and being ignited therein is expanded at a pressure practically
equal to that of the pressure in the passage into this larger space up to that point
of the stroke when the communication between the pump and cylinder is closed,
the remaining portion of the working stroke of the engine being performed by the
expansion of the gaseous mixture.
Secondly. To ignite the gaseous mixture, as that mixture enters the working
cylinder.
This object may be effected in various ways, for example:-(a.) By placing the
igniter described in the Specification of the Letters Patent granted to me, the said
William Foulis, No. 4843, A.D. 1878, in such a position that the gas on entering
the cylinder comes at once into contact with the hot platinum point thereof, and
whereby that part of the engine for covering and uncovering the igniter described
in my former Specification, No. 2422, A.D. 1880, is dispensed with.
(b.) By placing the igniter in communication with a small passage, into or
through which a jet, either intermittent or constant, of air and gas, is forced by
the compressing pump either directly or from a reservoir. By preference this
small jet of air and gas is in direct communication with the pump, and begins to
burn so soon as the pump commences to compress the gaseous mixture, the flamo
gradually lengthening out as the compression increases, until at the instant when
the gaseous mixture is allowed to enter the cylinder the flame is sufficiently long

page_text: to thoroughly ignite the entering gas. By preference one valve only is used
between the compressing pump and the chamber containing wire gauze hereinafter
described.
Thirdly. To enable the igniter to be dispensed with as soon as possible after the
engine begins to work. This is effected by using a knob of fireclay, asbestos, or
metal, insulated by a non-conductor from the metal of the cylinder, and so placed
within the cylinder that either the small jet of gaseous mixture or the main supply
thereof comes into contact with the said knob, and is by its heat ignited. This
knob may have strips of platinum across its surface so as to ensure still further
the ignition of the gaseous mixture.
"
Fourthly. To enable such an igniter as that herein referred to be altogether
dispensed with. This is effected by using a piece of slow burning fuse of sufficient
quantity to ignite the gaseous mixture until the knob has reached a sufficient
temperature to produce the ignition.
It is to be understood that although in the preceding clauses of this Provisional
Specification the aim has been to burn the gases gradually as they enter the
cylinder, yet it is to be understood that gas engines constructed with my improve-
ments may also be started by exploding the gaseous mixture in the cylinder, and
after a sufficient momentum of the engine has been attained such explosions may
be dispensed with, and the gas burnt gradually, as hereinbefore described.
Fifthly. To prevent the mixture from burning back into the passage leading to
the pump by the use of wire gauze, and to prevent the gaseous mixture from
burning in contact with the wire gauze during its period of intensest combustion.
This is effected by causing the gaseous mixture in passing from the compressing
pump to the cylinder to pass through layers of wire-gauze or their equivalents,
and thereafter through a thin tube or passage, which may be of annular or other
shape, both the wire gauze and this thin tube or space being kept cold by a water
jacket.
Sixthly. To allow the gaseous mixture before its exit into this thin space to
pass through a chamber surrounded by non-conducting material so as to heat the
gaseous mixture before its ignition. This chamber may be fitted with small tubes,
or their equivalent, for producing an extended surface. These tubes or their
equivalent are or may be heated by causing the burnt gases on their escape to the
exhaust valve to pass through or over them.
Seventhly. The object is to expel as much as possible the residue of foul gases
left in the cylinder at the termination of each exhaust stroke of the engine. This
object is or may be effected by attaching a pump to the engine, which will drive
fresh air through the cylinder during the latter part of the exhaust stroke. In
order that this pump may be as small as possible an inner casing or chamber may
be fixed to the inside of the cover of the working cylinder, into which the air from
the pump is discharged.
Eighthly. The object is so to construct the valve attached to the air and gas
mixing apparatus described in the aforesaid Specification, No. 2422, A.D. 1880, so
that the air and gas orifices always maintain a constant ratio of and to each other.
This is effected by making the valve casing or cylinder with a piston therein,
which piston as it rises or falls opens or closes the air and gas ports in this way in
a given proportion.
Ninthly. Under another head of these improvements the exhaust valve and the
admission valves, where the latter are used, are driven from one and the same
eccentric.
Tenthly. For the purpose of rendering gas engines reversible in their direction
of motion, the eccentric by which the valve or valves is or are driven is or may be
carried loosely in the crank shaft, in which case stops are placed equi-distant on
either side of the crank. Against one or the other of these stops the eccentric
rests according to the direction of motion of the engine.
Eleventhly. To regulate the speed and power of gas engines. This object is or
may be effected by placing a throttle valve on the suction pipe, or by placing a

page_text: chamber attached to the delivery end of the pump and coupled to the said pump
by means of a pipe provided with a stop cock. When it is required to deliver less
gas and air into the cylinder or cylinders of the engine than that which is due to
the whole stroke of the pump piston, this valve on the pipe between the pump and
the aforesaid chamber or chambers is opened to any desired extent, so that a portion
of the mixture of air and gas is forced thereinto at each compressing stroke, and
drawn out therefrom at each outward stroke. Or this object may be effected by
causing the pipe to make each alternate stroke without pumping the gaseous
mixture into the cylinder by means of a valve driven by an eccentric.
Twelfth. For the purpose of arresting the flow of oil from the cylinder into the
combustion chamber, and also for preventing particles of dirt from passing into the
cylinder, a groove is formed at the junction of the cylinder with the combustion
chamber which constitutes a receptacle for such oil and dirt.
:
Thirteenth. For the purpose of supplying gas to the igniter an apparatus
analogous to a wet gas meter is provided, and which is driven by a weight or
spring. This apparatus has two inlets, one for gas and the other for air, the areas
of the inlets being in the proportions of the mixture of air and gas.
Fourteenth. For the purpose of enabling the air and gas to be shut off from the
igniter as soon as possible, the supplementary piston is or may be mounted with
asbestos or equivalent material, which attains a high temperature more rapidly
than metal.
Lastly. Gas engines constructed with the aforesaid improvements may be placed
horizontally, vertically, or at any angle; they may be constructed with one single
acting cylinder, or they may be made with two single acting cylinders coupled to
cranks opposite each other, and having the compressing pump situated between the
two cylinders, in which case the compressing pump is made a double acting pump,
the same eccentric by preference driving the valves of both cylinders. It is to be
understood that although I prefer to so construct a two cylinder gas engine with
my improvements, yet I do not limit myself to the use of a compressing pump
placed between the two cylinders, nor do I limit myself to the use of a double
acting compressing pump, as single acting pumps may be substituted.

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 14th July
1881.
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 has for its objects
the following:
To so construct gas engines that the gaseous mixture is compressed in a pump,
from which it is allowed (during a portion of the stroke in accordance with the
relative capacities of the pump and cylinder) to flow directly (or through a
regenerator as hereinafter described) into a cylinder of larger diameter than the
pump (that is to say, whose capacity is greater than that of the pump) and this
mixture being ignited as it enters thereinto is expanded at a pressure practically
equal to that of the pressure in the pump up to that point of the stroke when the
communication between the pump and cylinder is closed, the remaining portion
of the working stroke of the engine being performed by the further expansion of
the gaseous mixture. The cylinder referred to is a cylinder such as is described
in the Specification of Letters Patent, No. 2422, granted to me, the said William
Foulis, as of the 15th June, A.D. 1880, wherein the piston works in a comparatively
cool portion, and the gaseous mixture ignited to work the engine is admitted into
a hot portion, the piston being preferably furnished with a tubular projecting
piece, as described in my said Specification of my said Patent, No. 2422, A.D. 1880.
The ignition of the gaseous mixture as that mixture enters the power cylinder
may be effected in various ways, for example:-By placing an igniter consisting
of a cap or nipple of platinum heated internally, and, as described in the Specifi-
cation of Letters Patent, No. 4843, granted to me, the said William Foulis, as of
the 28th November, A.D. 1878, in such a position that the gas on entering the
cylinder comes at once into contact with the hot platinum point thereof, whereby
that part of the engine for covering and uncovering the igniter, as described in
the aforesaid Specification of my Patent, No. 2422, A.D. 1880, is dispensed with;
or it may be effected by placing the said igniter in communication with a small
passage, into or through which an intermittent jet of air and gas is forced by the
compressing pump, and this jet begins to burn so soon (or nearly so) as the pump
commences to compress the gaseous mixture, the flame gradually lengthening out
as the compression increases, until at the instant when the gaseous mixture is
allowed to enter the cylinder the flame is sufficiently long to thoroughly ignite
the entering gas. By preference one valve only is used between the compressing
pump and the chamber containing wire gauze hereinafter described. To enable
the aforesaid igniter to be dispensed with as soon as possible after the engine
begins to work, a knob, piece, or layer of fireclay, asbestos, or metal is employed
(where the latter is used it is preferably insulated by a non-conductor from the
metal of the cylinder), and so placed within the cylinder that either the small jet
of gaseous mixture or the main supply thereof to the power cylinder comes into
contact with the said knob, and is by its heat ignited. This knob may have
strips of platinum across its surface so as to ensure still further the ignition of
the gaseous mixture. It is to be understood that although under the features
described in the preceding clauses of this Specification the aim has been to burn
the gaseous mixture gradually as it enters the cylinder, yet it is further to be
understood that in order to cause the engine to quickly acquire sufficient momentum
gas engines constructed with my improvements may also be provided with means
to enable them to be started by exploding instead of by gradually burning the

page_text: gaseous mixture in the cylinder, and after a sufficient momentum of the engine has
been attained by means of such explosions, such explosions may be dispensed with and
the gas burnt gradually as hereinbefore described. To effect this there may be used in
combination with gas engines constructed with my present improvements an igniter
formed of a cap or nipple of platinum beated internally, which is covered at each back
stroke of the piston by a sleeve upon the said piston and uncovered when the piston
has made a portion of its forward stroke as described in the Specification of my
before mentioned Patent, No. 2422, A.D. 1880, and when a sufficient momentuin
has been attained by the engine the jet which heats this cap or nipple may be
turned off. To prevent the mixture from burning back into the passage leading
to the pump by the use of wire gauze, and to prevent the gaseous mixture from
burning in contact with the wire gauze during its period of intensest combustion,
I cause the gaseous mixture in passing from the compressing pump to the cylinder
to pass through layers of wire gauze or their equivalents, and thereafter through
one or more thin tubes, spaces, or passages which may be annular or of other
shape, both the wire gauze and this thin tube or space (or these tubes or spaces)
being kept cold by a water jacket. I may allow the gaseous mixture before its
exit into this thin space to pass through a chamber surrounded by non-conducting
material so as to heat the gaseous mixture before its ignition. This chamber may
be fitted with small tubes or their equivalent for producing an extended surface,
these tubes or their equivalent being heated by causing the burnt gases on their escape
from the power cylinder to pass through or over them. To expel as much as
possible the residue of foul gases left in the cylinder at the termination of each
exhaust stroke of the engine the same pump which compresses the gases may be
caused to drive fresh air through the cylinder during the latter part of the exhaust
stroke. An inner casing or chamber similar to that marked f in the Drawing
accompanying the Specification of my before mentioned Patent, No. 2422,
A.D. 1880, may be fixed to the inside of the cover of the working cylinder, into
which the air from the pump is discharged.
In order that the air and gas orifices of the valve attached to the air and gas
mixing apparatus, described in the aforesaid Specification of my Patent, No. 2422,
A.D. 1880, shall always maintain a constant ratio of and to each other, the valve
casing or cylinder is provided with a piston, which piston as it rises or falls opens
or closes the air and gas ports in this way in a given proportion, it being explained
that this valve is not necessarily attached to the aforesaid mixing apparatus.
Under another head of these improvements the exhaust valve and the admission
valves, where the latter are operated by an eccentric, are driven from one and the
same eccentric. For the purpose of rendering the engine reversible in its direction
of motion the eccentric by which the valve or valves is or are driven is or may be
carried loosely in the crank shaft, in which case stops are placed equidistant on
either side of the crank. Against one or the other of these stops the eccentric
rests, according to the direction of motion of the engine, it being explained that in
shifting the eccentric for reversing the pump crank is necessarily also shifted to
the opposite side of the driving cranks. To regulate the speed and power of the
engine a throttle valve is or may be placed on the suction pipe, or a chamber or
chambers may be employed attached to the delivery end of the pump, and coupled
to the said pump by means of a pipe provided with a stop cock or valve. When
it is required to deliver less gas and air into the cylinder or cylinders of the engine
than that which is due to the whole stroke of the pump piston, this cock or valve
on the pipe between the pump and the aforesaid chamber or chambers is opened to
the required extent, according to the speed which the engine has attained, so that
a portion of the mixture of air and gas is forced thereinto at each compressing
stroke, and drawn out therefrom at each outward stroke. For the purpose of
arresting the flow of oil from the working cylinder into the combustion chamber,
and also for preventing particles of dirt from passing into the working cylinder, a
groove is formed at the junction of the working cylinder with the combustion
chamber, which constitutes a receptacle for such oil and dirt. For the purpose of

page_text: supplying gas and air to the igniter an apparatus analogous to a wet gas meter is
provided, which apparatus is driven by a weight or spring, and has two inlets, one
for gas and the other for air, the areas of the inlets being in the proportions of the
mixture of air and gas. In place of the before mentioned knob of fireclay or other
material, for the purpose of enabling the air and gas to be shut off from the igniter
as soon as possible, a supplementary piston analogous to the supplementary piston
described in my said former Specification of my Patent, No. 2422, A.D. 1880, but
without the sleeve for covering the igniter or the contracted chamber at the end, is
or may be mounted with asbestos or equivalent material, which attains a high
temperature more rapidly than metal, and will when it attains a sufficient
temperature act as an igniter.
Aud in order that the means by which the foregoing objects are or may be
practically employed may be fully understood, I have appended hereto Drawings
illustrating a gas engine constructed according to some of my said improvements
and various details, and illustrations of others of my said improvements, as herein-
after described. Of these Figure 1 is a side elevation of a single cylinder gas
engine; Figure 2 a plan, and Figure 3 an elevation of the back end- thereof;
Figure 4 is a longitudinal section of the back portion of the cylinder forming the
combustion chamber; Figure 5 is a transverse section taken on the line 1, 2,
(Figure 4); and Figure 6 is a horizontal section taken on the line 3, 4, (Figure 5),
these Figures 4, 5, and 6 being drawn to a scale larger than that to which Figures
1, 2, and 3 are drawn.
The power cylinder of the engine is constructed in two portions A and A',
separated by a layer of material of low conducting power, the part A being lined
with non-conducting material (with or without a layer of metal thereupon), and
being covered with the same to prevent transmission of heat, this part A forming
the hot cylinder or chamber, into which the gaseous mixture is admitted. The
part A¹ is surrounded by cold water, and forms the cooler portion, constituting the
working cylinder in which the piston works, this piston being preferably provided
with a tubular projecting piece lined with refractory material, for the purpose of
preventing as much as possible the transmission of heat from the portion A to the
portion A¹, all according to the Specification of my aforesaid Patent, No. 2422,
A.D. 1880. There may be formed between the two portions A and A' a groove
or recessed part extending around the cylinder, into which surplus oil and dirt will
pass, so as not to impede the working of the engine. Figure 3A is a section at the
junction of the two parts of the cylinder, shewing this groove (where it is marked a²)
with a portion of the water casing of the part A¹, and the lining and covering of
the part A, and also the piston and a portion of the tubular projecting piece there-
upon, as before mentioned. The piston is connected to the crank shaft B after the
manner commonly adopted in motive power engines. The pump C is driven from
the shaft B by the crank pin c, to which the pump rod c² is attached. The said
crank pin c is placed at an angle to the rear of the engine crank b in accordance
with the first herein before mentioned object of my Invention. The amount of this
angle is determined by the difference in capacity of the pump and working cylinder
in order to admit the compressed mixture of air and gas into the cylinder during
such a portion of the latter part of the back stroke of the pump piston, and of such
a corresponding portion of the first part of the forward stroke of the working
piston of the engine cylinder, in accordance with the respective capacities of the
pump and engine cylinder, as that the pressure of the said mixture in the lesser
capacity (viz., that in the pump) is the same as that which the said mixture will
attain when admitted into the larger space (viz., that in the cylinder), and expanded
by the heat thereof. The pump is preferably cooled by a water casing. The
mixture of air and gas is drawn into the pump C through ordinary or suitable
valves, and is forced therefrom through the delivery valve, and thence by the pipe
or passage through the layers of wire gauze D (see Figures 4 and 5) into the
annular space E, which is formed between the interior of the inlet passage at e and
the exterior of the plug e², fixed concentrically in the said passage. From this

page_text: annular space E the said mixture of air and gas issues into the cylinder A through
the passage F, which is preferably lined with refractory non-conducting material.
This passage F and the position of the knob e² may be varied in any desired
manner. For example, the modified form shewn in Figure 44 may be adopted,
wherein the passage F is contracted in front of the knob e', and enlarges again
towards its opening to the cylinder. The refractory material of which this pas-age
is formed, or with whih it is lined, may become sufficiently heated to effect the
ignition of the gaseous mixture as it enters the cylinder. A metal covering may
be placed upon this refractory material. The chamber which contains the wire
gauze D is surrounded by a jacket d, which may extend around the other parts
of the apparatus at the end of the cylinder, and may or may not be made in one
casting therewith as shewn, and in the space between this jacket and the said
chamber, and other parts which it surrounds, water circulates by inlet and outlet
pipes and passages d² for the purpose of reducing the temperature sufficiently to
prevent the wire gauze from being destroyed. These pipes may also communicate
with the water casing around the part of the cylinder A' to give the circulation
therethrough, and also with the water casing of the pump if it be provided with
a water casing. A small pipe g (furnished with a-valve closing on the forward
stroke of the pump) leads from the compressing pump C, and terminates in a
nozzle g², with an end piece preferably of fire clay or of other refractory material,
the said nozzle being situated in the passage G formed in the cylinder cover, and as
shewn in the enlarged view Figure 6. Soon after the pump begins its compression
stroke, the mixture of air and gas is discharged from the jet nozzle g³, and being
so discharged at low pressure is easily lighted by the igniter H consisting of
a cap or nipple of platinum, heated internally by a jet of a mixture of air
and gas, as described in the Specification of my aforesaid Patent, No. 4843,
A.D. 1878, the end piece of the nozzle h, at which the heating jet is burned, being
of fireclay or other refractory material, and having a small recessed part h² at its
end, which is brought so close to the interior of the nipple as to leave but a small
space between itself and the said nipple, this arrangement facilitating the
combustion of the gases and the heating of the nipple. As the pump pressure
increases this flame lengthens out until the mixture of air and gas enters the
cylinder from the pump, when the said flaine is of sufficient length to reach the
passage F and ignite the mixture of air and gas entering the cylinder through the
said passage and the compound gaseous mixture continues to burn steadily during
the whole time of its admission into the cylinder. The exhaust valve I (see
Figure 5) is contained within the exhaust passage I². The said valve I is lifted
by means of the tappet lever i, keyed upon a rocking shaft 2, which shaft is
rocked to cause the tappet lever i to open the exhaust valve or allow it to close by
the eccentric on the driving shaft B, the rod of which is connected to the
lever, keyed to the shaft 2. The pin i, which connects the rod with the
lever, engages in a slot in the said lever 25. A rod is connected at one end to
the pin and at the other end to a screw is engaging in the screw nut 20 (see
Figure 5), provided with a hand wheel 20 and mounted in the bracket ; it will
be readily seen that by turning this screw nut in one or other direction the pin e
will be raised or depressed in the slot in the lever ³, and by this means the extent
of opening of the exhaust valve I may be regulated. The exhaust gases escape
by the pipe I³ (Figures 1 and 3). A knob or piece R of fireclay, or asbestos, or
metal, on a layer of asbestos or other similar material, is so placed in the cylinder
that the flame of the gaseous mixture coming in contact with it rapidly heats it to
a sufficient temperature to ignite the mixture of air and gas as it enters the
cylinder, and when this degree of heat is attained the supply of gas to the igniter H
and to the nozzle g² may be discontinued. Strips or pieces of platinum may be
fixed to this knob R so as to facilitate the proper ignition of the air and gas.
This knob R may be carried in a bracket affixed to the cylinder cover, as shewn, er
affixed to the side of the cylinder or to the projecting tubular piece on the piston; or
it may consist of a layer or piece of refractory material carried by a supplementary

page_text: piston like that marked g in the Drawing accompanying the aforesaid Specification
of my previous Patent, No. 2422, A.D. 1880. A plug similar to that marked R
but of smaller size may be placed in the passage G if desired to ignite, when it has
become sufficiently heated, the gas from the nozzle g². Where the engine is to be
arranged to be started by a series of explosions, an igniter consisting of a cap or
nipple of platinum heated by an internal flame may be used in place of the plug
or knob e², the said igniter being covered during the latter portion of the backward
stroke of the piston and during the first part of the forward movement of the same
by a sleeve upon the piston, as described in the Specification of my beforementioned
Patent, No. 2422, A.D. 1880, this arrangement allowing of the engine being started
by a series of explosions until sufficient momentum has been attained and the
knob R has become sufficiently heated to ignite the gases when the flame which
heats this igniter may be turned off and the engine will work, as herein before
described, Or these explosions at the first starting of the engine. may be effected
by arranging an eccentric on the shaft of the engine so as to open the valve to
admit the gaseous mixture to the jet g² only at or about the time when the
explosive mixture has all entered the combustion chamber A. The passage from
the valve of the pipe g to the jet g³ may be of sufficient capacity to contain
enough gaseous mixture to sustain a very small flame at the said jet when the said
valve is closed, which flame will intermittently lengthen out to ignite the gaseous
mixture entering the cylinder.
Figure 6 illustrates an arrangement of igniter which may be employed in place
of the jet from the pump. The igniter H is placed in the passage G with its
nipple piece set back a short distance, so that the nipple is protected from the
direct blast of the gaseous mixture passing through the passage F from the space E,
but so that the said mixture is at once ignited by the said igniter.
As hereinbefore stated I prefer to employ but one delivery valve between the
pump and the power cylinder; Figure 7 represents such a single delivery valve for
admitting the compressed mixture of air and gas to the cylinder through the pipe c*.
The area of this valve z presented to the pressure from the pump on the side z² is
smaller than that presented to the pressure on the opposite side z³ nearest to the
power cylinder. Owing to this difference of area the pressure in the power
cylinder during the back stroke of the piston of the said power cylinder serves to
keep the valve closed, but when the pressure in the pump has become greater_than.
the pressure in the power cylinder in the proportion of the areas of the valve it
will lift the valve, and immediately on rising the full pressure bears upon the
whole area of the bottom of the valve, and gives a quick opening thereto. The
aforesaid valve may be made with areas much greater in difference than the
difference in pressures, and the valve may be raised from its seat by the action of
the eccentric, when the pump pressure will act upon the full area of the valve, and
raise it quickly. Where this last mentioned arrangement is used, or where the
inlet valve is otherwise arranged so as to be lifted by an eccentric, the same eccentric
which operates the exhaust may also be employed to actuate the inlet valve.
Figure 7 is a diagram illustrating this arrangement, where the exhaust valve I is
operated essentially as before described, and the inlet valve J is operated by the
arm j, axis, and tappet ³, acting to open the inlet valve on the stroke of the
eccentric rod 2, the reverse from that which opens the exhaust valve.
Of course,
when this arrangement is employed, the eccentric and rod may be between the
pump and power cylinder, or otherwise arranged, so that it is in convenient
proximity to both the inlet and exhaust valves.
The inlet valve of the pump may be of the ordinary description of pump valves,
the mixture of air and gas being drawn from a mixing chamber; or the air and
gas may be drawn into the pump in the regulated proportion, and expelled there-
from separately, in which case either ordinary pump valves or a single valve like
that, Figure 7, may be used upon both the gas and air inlet pipes from the pump to
the
power cylinder.
Figures 8 and 9 represent in horizontal and vertical sections respectively a valve.

page_text: for regulating the proportions of the air and the gas, and the quantity admitted
for attachment to the air and gas mixing apparatus described in the Specification
of my said Patent, No. 2422, A.D. 1880. The valve consists of an inner part
attached to the valve spindle 12 of the mixing apparatus described in my said
Specification, the said inner part sliding vertically in the outer part y. The air
and gas inlets marked t, u, respectively will consequently be opened more or less,
according to the distance to which the valve rises. The part & may be turned by
the handle x2, and thereby the extent of the gas inlet u may be regulated. The
air inlet in this moving part x is made larger than in the other part, so that the
altered position of the said moving part x to adjust the gas inlet does not affect
the air inlet.
Figure 10 represents in elevation, Figures 11 and 12 in vertical section
respectively, taken on the line 5, 6, and 7, 8, (Figure 13), and Figure 13 in
horizontal section on the line 9, 10, (Figure 12) this valve adapted for use, where
the mixing apparatus before referred to is not employed. The inner part x is
capable of being turned by a handle ³, so that the parts t, u, therein for the air
and gas respectively coincide more or less, that is to say, fully open or partly close
the corresponding ports in the outer casing y of the valve, so that by one movement
the air and gas inlets are adjusted, so that air and gas are admitted in constant
proportions, essentially as described with regard to the vertical motion of the inner
part of the apparatus, Figures 8 and 9. In order to regulate the proportion of
gas to the air admitted the inner part x is capable of being raised by the screw x³,
so that the gas port in the one part obstructs more or less the gas port in the
other, and more or less gas passes in proportion to the quantity of air. The
openings or ports for the air are made as in the example, Figures 8 and 9, the
one larger than the other, so that the movement of the inner part x to regulate the
gas inlet does not affect the air inlet.
In this last arrangement the pressure of gas may be maintained by a governor
at or a very little under atmospheric pressure, so that in case of the engine stopping
no gas will escape.
Figures 14 and 15 illustrate means by which the regeneration of the heat of the
spent gases may be carried into effect; Figure 14 is a vertical transverse section of
the inlet end of the power cylinder taken on the line 11, 12, (Figure 15); Figure 15
is a vertical longitudinal section taken on the line 13, 14 (Figure 14). The parts
as shewn are somewhat different in their form and arrangement from the arrange-
ment of the same parts in Figures 1 to 6, but they act essentially in the same
manner, and parts which correspond with similar parts in Figures 1 to 6 are marked
with the same letters of reference. In the passage e between the wire gauze D
and the annular space E at the outlet to the power cylinder is a chamber K,
through which the exhaust gases pass to the outlet valve by the passage I' after
acting in the power cylinder. Fixed to the sides of this chamber K are plates L
carrying tubes (preferably of fireclay or other refractory material) which tubes
form communications from the space m between the one plate L and the casting to
the space n between the other plate L and the cylinder cover or end plate. The
last mentioned plate L carries the knob e² forming the annular space at E for the
passage of the gases as before described. The exhaust gases pass from the cylinder
into the chamber K and between the tubes and heat the said tubes. The
entering mixture of air and gas after passing through the wire gauze D into the
space m, passes through the tubes 7 and takes up heat therefrom, and thence flows
into the space n, and therefrom through the annular space E around the plug e³,
and is ignited as it issues into the power cylinder as before explained. It will be
obvious that the same object may be attained if larger passages or chambers be
substituted for the series of tubes 1, the said passages being preferably lined with
non-conducting material. It will be understood that the exhaust gases may be
passed amongst the tubes on their way from, in place of on their way to, the
exhaust valve.
The same pump which on the one side of its piston forces the gaseous mixture

page_text: into the power cylinder may be arranged so that it drives air into or through
the power cylinder to clear it of foul gas, and to facilitate this clearance an
inner casing similar to that marked ƒ in the Drawing accompanying the
Specification of my before mentioned Patent, No. 2422, A.D. 1880, may be fixed to
the inside of the cover of the power cylinder into which the air from the pump
is discharged. Where this casing f is used the knob R may be carried by the
said casing.
The controlling of the quantity of gaseous mixture admitted to to the power
cylinder may be carried into effect by the arrangement illustrated in Figure 16.
A valve q is arranged in the chamber Q (which receives the gaseous mixture from
the pump) to open more or less or close a communication between this chamber
and a receiving chamber or chambers. This valve is opened by the tappet r
actuated by the eccentric which operates the exhaust valve by the rod 2, attached
at one end to a collar on the eccentric rod is, the other end being attached to a
pin engaging in a slot in the lever keyed to the axis which carries the said
tappet r. A rod acted upon by an ordinary governor is also connected to the
pin, so that as the said rod rises or falls under the action of the governor the
pin will be raised or lowered in the slot in the lever, and a greater or less
degree of opening be given to the valve q to cause a greater or less amount of the
explosive mixture to pass into the power cylinder at each stroke according to the
speed of the engine, the surplus mixture at each stroke passing into the receiving
chamber or chambers not shewn, but which will be connected to the flange at s.
From this chamber or these chambers this surplus mixture is drawn back into the
pump at its next forward stroke.
Figure 17 represents in vertical section an apparatus, consisting of a meter for
conveying gaseous mixture to the igniter H; Figure 18 is a transverse section of
the drum of this meter and its casing. This casing is marked 1, and the drum
rotates therein in a manner analogous to a wet gas meter. The said drum is
preferably constructed with a number of chambers or trumpet like recesses in its
periphery, communicating at one end with the casing 1 and at the other end with
the interior of the drum, the said recesses as the drum is rotated receiving air and
gas from the casing 1, and as the said recesses pass down into the liquid in the
meter this gas and air is forced into the interior of the drum and passes out
therefrom by the pipe 3 to the jet which burns inside the platinum nozzle
(H, Figure 6). The pipe by which the air and gas are admitted to the casing
is marked 2, and it has upon it a valve like that shewn in Figures 10 to 13 for
regulating the quantity and proportions of the air and gas drawn into the casing 1.
Rotation may be given to the drum by any suitable means. A convenient method
is shewn in the Drawings, according to which method the rotation is obtained by
means of weights 4 attached to a cord 5, passing over a pulley 6 and multiplying
pulleys 7, and thence passing around a barrel 8 geared to the axis of the drum by
the wheels 9, 10, so that the descent of the weights 4 causes the drum to revolve.
As soon as the gas is cut off from its passage along the outlet pipe from the drum,
the revolution of the drum will at once cease owing to the counteracting pressures
of the incoming gaseous mixture and the weights 4.
The action of the engine is as follows:-As before explained the stroke of the
pump piston is to the rear of the stroke of the piston of the power cylinder to an
extent depending upon the relative capacity of the pump and working cylinder,
so that the compressed mixture when it passes into the larger area of the working
cylinder, and is expanded by heat, is at the same or nearly the same pressure as
that at which it was when in the smaller area of the pump. For the sake of
example I will assume that the relative capacities of the pump and working
cylinder are such as that to fulfil the above mentioned condition the pump crank
.is one third of a stroke to the rear of the crank of the power cylinder. During the
forward stroke of the piston of the pump the mixture of air and gas is drawn into
the pump cylinder, the piston of the working cylinder having during this time
. been urged forward through about the last two thirds of its forward stroke and

page_text: about the first one third of its return or back stroke. At the beginning of its back
stroke the exhaust valve is opened, remaining open during a time depending on the
position of the eccentric rod in the slot of the lever actuating the said exhaust
valve. The said piston of the working cylinder in completing its back stroke
compresses the exhaust gases remaining in the cylinder, and the pump piston
during its back stroke at this time compresses the explosive mixture in the pump,
until at or about the time at which the piston of the working cylinder has com-
pleted its back stroke and the pump piston is commencing the last third of its back
stroke the pressure on the side of the delivery valve (Figure 7, where this valve is
employed) next the pump overcomes the pressure on the other side, and the valve
lifts and the. gaseous mixture enters the part A of the cylinder, passing through
the wire gauze D and thence through the space E, issuing therefrom (at a velocity
which prevents back firing) into and from the passage F, and meeting with the jet
of flame from the nozzle g² or the heated plug R, or its equivalent, as the case may
be, is burned in the combustion chamber formed by the part A of the cylinder and
the tubular projecting piece on the piston of the working cylinder, the expansion
driving the said piston forward. When the pump piston reaches the end of its back
stroke the delivery valve closes, the last two thirds or thereabouts of the forward
stroke of the piston of the working cylinder being performed by the aforesaid
expansion of the hot gases behind it. The supply of gas and air to the nozzle g³
commences shortly after the pump piston begins its back stroke, the said gas and air
as it isssues from the said nozzle being ignited by the adjacent igniter H, and as the
pressure in the pump increases, the fame lengthens out, until at the period when
the gaseous mixture is admitted to the working cylinder the said flame is sufficiently
long to fire the entering mixture. After a time the knob R will become sufficiently
heated to ignite the mixture as it enters the cylinder from the space E and passage
F, and then the supply of gaseous mixture to the jet g2 and to the igniter H
may be discontinued, the pipes or passages which convey this mixture to the said
jet and igniter being provided with cocks by which they may be closed.
Gas engines constructed with. my herein before described improvements may be
placed horizontally, vertically, or at any angle; they may be constructed with one
single acting cylinder, as described, or they may be made with two or more single
acting cylinders coupled to cranks opposite each other, and having each a com-
pressing pump, or having in the case of an engine of two cylinders one compressing
pump situated between the two cylinders, in which case the compressing pump is
made a double acting pump, the same eccentric by preference driving the valves of
both cylinders. The space E may be of other form than that shewn, for example,
it may be a simple slit or a series of slits, the essential point being that the
mixture of gas
and air will pass therethrough, so as on the said gaseous mixture
being ignited as it issues therefrom it will not fire back into or to the rear of this
said space or orifice E. In place of the body of wire gauze D being of circular
form, as shewn, it may be of oblong, oval, or other form, or there may be two or
more smaller bodies of wire gauze in separate passages communicating with the
main passage for the gaseous mixture, and each surrounded by the water casing,
the object being to cool the wire gauze to its central. parts and reduce as much as
possible the wire drawing of the gaseous mixture.
Having now described and particularly ascertained the nature of my said
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 observe in conclusion that I wish
t to be understood that I do not limit myself to the precise details herein before
described and illustrated in the accompanying Drawings, as the same may be
varied without departing from the nature of my Invention, but what I consider to
be novel and original and therefore claim as the Invention secured to me by the
ereinbefore in part recited Letters Patent is,―
First. The general arrangement and combination of parts constituting the gas
engine, hereinbefore described with reference to the accompanying Drawings.
Second. In gas engines the combination of a pump and a power cylinder

page_text: consisting of a combustion chamber which becomes highly heated and a working
cylinder which is kept comparatively cool, and which is of larger capacity than
the capacity of the pump, wherein the stroke of the pump is made to the rear of
the stroke of the piston of the working cylinder to such an extent in accordance
with the relative capacities of the pump and working cylinder, that the mixture
of gas and air when it passes into the power cylinder is expanded during its
passage thereinto at a pressure equal or about equal to that in the pump
Third. In gas engines the means for igniting the gas and air in the power
cylinder consisting in the combination of an igniter (H) and passage (G) with an
intermittent jet (92) in communication with the pump which supplies air and gas
to the working cylinder, and arranged and operating essentially as and for the
purpose herein before described and illustrated more particularly in Figure 6 of
the accompanying Drawings.
Fourth. The use in gas engines of a knob or piece of fire-clay, or asbestos, or
like material, or of metal, or of fire-clay, or asbestos, or like material mounted with
metal, in combination with an igniter or means for igniting the mixture of gas
and air as the said mixture enters the cylinder, whereby the said knob is heated
during the first period of the engine's work, and thereafter the said knob when it
shall have become raised to a sufficient temperature itself forms the means of
igniting the gaseous mixture during the subsequent action of the engine, and thus
enables the supply of gaseous mixture to the igniter to be discontinued, essentially
as hereinbefore described. Also the modification wherein the same object is
effected by refractory material carried by a supplementary piston, essentially as
herein before described. Also providing such a knob or piece or layer of refractory
material in the passage G for igniting the gaseous mixture issuing from the
igniting jet (g²).
Fifth. In gas engines the combination with, and use in the entrance pipe or
passage for the gaseous mixture to the power cylinder of wire gauze and an
annular, or other contracted space or orifice (or spaces or orifices, or its or their
equivalents), through which the entering gaseous mixture passes at a velocity
sufficient to prevent back firing, together with means for preventing the over-
heating of the said parts, essentially as herein before described with reference to the
accompanying Drawings.
Sixth. The combination with an arrangement of wire gauze and contracted
space or orifice, or spaces or orifices and means for keeping the same cool as claimed
in the preceding fifth claiming clause, of a passage in front of the said contracted
space or orifice, or spaces or orifices, essentially as described with reference to the
passage F, Figures 4, 6, and 44 of the accompanying Drawings.
Seventh. The combination in gas engines of a regenerator between the wire
gauze and contracted space or spaces claimed in the preceding fifth claiming clause,
for causing the heat or a part of the heat of the burnt or exhaust gases to be taken
up by the entering gases, essentially as hereinbefore described with reference to
Figures 14 and 15 of the accompanying Drawings.
Eighth. The employment in the passage, or each of the passages, between the
pump and power cylinder, arranged as claimed in the second preceding claiming
clause, of one valve with different areas for opening at the requisite pressure,
essentially as hereinbefore described with reference to Figure 7 of the accompanying
Drawings.
Ninth. The arrangement for governing the quantity of explosive mixture
admitted to the engine, essentially as and for the purpose herein before described
and illustrated in Figure 16 of the accompanying Drawings.
Tenth. In the power or working cylinders of gas engines, the groove or recessed
part a (Figure 34) between the two portions of the power cylinder, for the purpose
described.
Eleventh. A valve for admitting the required regulated quantities of air and gas
to the pump, and to the igniter heating jet of gas engines, and for adjusting the
proportions thereof so that when adjusted their passages may be regulated (either

page_text: by hand or by the bag of the air and gas mixing apparatus) to admit the air and
gas in the constant proportion the one to the other for which the valve has been
set, essentially as hereinbefore described with reference to Figures 8 to 13 of the
accompanying Drawings.
Twelfth. The use in combination with gas engines, of apparatus for supplying
gas and air to the igniter heating jet of the engine, the said apparatus being
constructed essentially as hereinbefore described with reference to Figures 17 and 18
of the accompanying Drawings.
Thirteenth. In gas engines the combination of an inner casing or chamber at the
back end of the power cylinder (and similar to that marked fin Figures 1 and 2
of the Drawings of the Specification of my former Patent, No. 2422, A. D. 1880)
with means for causing a current of air to pass thereinto during the latter part of
the forward stroke of the pump piston, essentially as herein described.
Fourteenth. The combination with gas engines, constructed essentially as here-
inbefore described for what has herein before been termed the gradual ignition of
the gaseous mixture as it enters the combustion part of the power cylinder, of
means for starting the engine by a series of explosions or ignition of the gaseous
mixture after the full charge has entered the said combustion part of the cylinder,
essentially as herein before described.
Fifteenth. Placing the hereinbefore described igniter H in such a position in
communication with the passage through which the gaseous mixture passes from
the contracted space or spaces into the power cylinder, that the said igniter at once
ignites the said mixture, essentially as hereinbefore described with reference to
Figure 64 of the accompanying Drawings.
In witness whereof, I, the said William Foulis, have hereunto set my hand'
and seal, this Twelfth day of July, in the year of our Lord One thousand
eight hundred and eighty one.