IMPROVEMENTS IN GAS ENGINES
Year: 1883

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 3rd July 1883.
WILLIAM FOULIS of Glasgow in the County of Lanark, North Britain Civil
Engineer "IMPROVEMENTS IN GAS ENGINES"
This Invention relates to Improvements in Gas Engines. It consists in the First
place of an apparatus for mixing in measured quantities the air and gas which are
burned in the cylinders of such Engines and which for brevity's sake I call a
"mixing meter."-This "mixing meter" consists of a casing in the lower part of
which is a moveable diaphragm connected all round its circumference by a
flexible piece of leather to the bottom of the chamber.-The interior of the
space enclosed by this diaphragm and leather is in communication, with the
atmosphere. The diaphragm is connected at its centre to the outer end of a
lever or its equivalent, preferably acted upon by a spring or its equivalent,
the tendency of which spring is to press the diaphragm downwards.-This lever is
connected by a link to a rotating valve in which, as well as in the casing wherein
the valve reciprocates, are two ports, or the lever may be dispensed with in which
case the arm of the rotating valve is connected direct to the diaphragm. At the
upper part of the casing is a second diaphragm connected to the body of the casing
by flexible leather.-This diaphragm carries at its centre a conical valve working
in a seat and operates so as to control the supply of gas after the well known
manner of a gas governor.
.
The action of this apparatus is as follows:-The pump on the engine when in
operation forms a partial vacuum in the chamber so that the lower diaphragm rises
by the pressure of the atmosphere below it and in rising causes the cylindrical
valve by means of its connections thereto to be rotated to an extent which enables
the air and gas ports therein to be opened and air and gas to be drawn in, in the
requisite proportions to form an explosive or combustible mixture.-The ports for
the air and gas are respectively made of areas corresponding to the volumes of air

page_text: :
and gas necessary to constitute the mixture and the proportion of these areas may
be altered from time to time as required by means of an end adjustment.
The order of construction of the apparatus hereinbefore described may be
inverted and in place of using the diaphragms and flexible leather connections,
pistons working in cylinders may be substituted.
In place of using in any "mixing meter" the rotating valve herein before
described I may substitute a valve of the construction shewn at Figures 8, and 9,
Sheet 4, of the Drawings of my Specification N° 180. A.D. 1881, or any other
suitable valvular arrangement.
Secondly. For the purpose of igniting the mixture of gas and air which is
burned in the cylinders of gas engines I use a burner or igniter which consists of a
short tube of fire-clay or other refractory material, whose inner end is perforated,
or upon or against which may be fastened perforated plates or layers of wire gauze
and through which the mixture of air and gas issues from a passage leading from a
reservoir hereinafter described as attached to or in connection with the pump of
the engine. This short tube of fire-clay has towards its outer end a piece raised
upon or projecting from it towards its centre, and the hollow of the tube is of
sufficient length or depth to allow of the mixture of air and gas obtaining an
eddying or analogous motion which is caused by the projection interfering with the
direct discharge of the mixture of air and gas from the hollow of the tube.-By
this means the ignition of the mixture of air and gas is at all times insured as in
the event of the incoming mixture of air and gas through the burner being blown
out the heat of the fireclay projection re-ignites it.-In this improved igniter the
flow of the mixture of air and gas is a continuous flow but intermittent in quantity
or intensity. Instead of a projection inside the tube, the flame from the opening
of the igniter may be allowed to play into a cup of fire-clay or otherwise on a piece
of fire-clay so as to produce the necessary eddying action on the current of gas,
and ignite the gas, when blown out.
For the purpose of effecting the initial lighting of the igniter at starting the
engine the cylinder cover has a hole formed in it in communication with a hole in
the tube of the igniter, so that a match or its equivalent can be passed into this
hole to the mixture of air and gas.-The hole is provided with a screwed plug or
its equivalent for opening or closing it as required.-In the event of the quantity
of air and gas burned in the cylinder, when the engine is running light or without
load being insufficient to maintain the knob or its equivalent on the piston or
piston attachment at a temperature sufficient to ignite the incoming air and gas,
provision is made for automatically re-admitting the mixture of air and gas througli
the igniter by means of a valve actuated by the speed governor, this coming into
operation before the temperature has become too low to ignite it.
Thirdly. For the purpose of enabling the use of the igniter herein before
described to be dispensed with after the engine has been working for a short time,
the end of the piston or piston attachment nearest to the igniter is provided with
a cup of fireclay or other refractory material in whose lower part is a projection or
knob or instead of this projecting knob several small holes may be formed in the
bottoin of the cup. This cup in place of being attached to the piston, may be
attached to the cylinder cover.-This cup may be carried in a projection on the
piston or on an attachment thereto which when the piston is at the end of its
inward stroke-enters an opening in a secondary cylinder cover which has formed
around it a groove in which a portion of the mixture of air and gas entering the
cylinder has an eddying or analogous motion imparted to it for the purpose of more
completely ensuring its ignition.
Fourthly. In my aforesaid Specification N° 180 A.D. 1881, I have stated that I
prefer to employ but one delivery valve between the pump and the power cylinder
but according to my present improvements I apply an admission valve situated as
close as possible to the admission port leading into the cylinder and this valve I
operate by a rapidly moving piece of mechanism such as a tappet or its equivalent.
This valve is prevented from becoming too 'hot when working by the wire gauze

page_text: arrangement hereinafter described also by being kept cool by a water casing
surrounding the chamber which contains it.
Instead of the annular space referred to and marked E, in my aforesaid Specifi-
cation N° 180 A.D. 1881 I place the wire gauze or its equivalent in the admission
port at a distance sufficiently far back from the inside face of the cylinder cover as
to prevent the heat of the combustion in the cylinder destroying the wire gauze
which is also kept cool by means of water circulating through the casing containing
it. This cover is further kept cool by the inner or secondary cover separated from
the other cover by a layer of asbestos or its equivalent.
For the purpose of producing as large a heating surface as possible in the com-
bustion cylinder of the engine. I form that portion of the piston or the attachment
to the piston which works in the combustion cylinder as well as the interior. of
such cylinder itself of corrugated or deeply fluted surfaces after the manner of fins
or webs or I may form the said portions of the piston and the interior of the
cylinder into a series of thin annular projections working.into each other so as to
increase the heating surface.
Fifthly. According to the present improvements the reservoir for holding the
mixture of air and gas besides being a means for supplying the igniter is formed
of dimensions sufficient to contain a quantity of mixed air and gas for starting the
engine.
Sixthly According to the present improvements the end portion of the cylinder
that is to say the end which contains the igniter and admission and exhaust ports,
is formed in one piece with the end of the pump.-These together constituting a
casting which is fixed to the bed-plate or sole of the engine.-The hot or combus-
tion cylinder is bolted to this casting and carries at its forward end the working
cylinder which is supported in a guide or guides so that it can move freely outwards
with the expansion lengthwise of the combustion cylinder..
Seventhly. For the purpose of regulating the speed of the engine the inlet valve
hereinbefore described is caused to shut at different: periods of the piston's
stroke by the action of a speed governor and the residue of air and gas left in the
pump after the valve is shut accumulates in the reservoir until its, pressure opens a
loaded valve and allows the surplus. to escape back into the pump during its
outward stroke. Or the speed governor may be connected so as to operate a valve
in the passage between the pump and the reservoir, so as to allow a portion of the
gaseous mixture to pass from the pump to the reservoir during the compression
stroke and from the reservoir to the pump during the back stroke, or the speed
governor may similarly operate a valve in the passage between the pump and the
mixing meter. .
.Eighthly. The reservoir hereinbefore referred to as that to which the igniter is
connected is or may be made sufficiently large to hold enough of the mixture of air
and gas under pressure for starting the engine, and the engine may be provided
with a hand pump for charging this reservoir when necessary.
$
Ninthly For the purpose of more efficiently lubricating the pistons of gas
engines, an oil pump is provided and is so adjusted relatively with the piston that
a cam or tappet or the equivalent thereof forces in the plunger and causes it to
discharge a small quantity of oil at each stroke into the cylinder, during the time
that the piston is passing the said orifice.
Lastly. It is to be understood that the aforesaid improvements may in whole
or in part only be employed in a single engine.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Foulis in the Patent Office on the 3rd January 1884..
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.
5
My said Invention consists in the First place of an apparatus for mixing in
measured quantities the air and gas which are burned in the cylinders of of such
engines and which for brevity's sake I.call a "mixing meter."This mixing meter
is shewn at Figures 1, and 2, of the accompanying Drawings of which Figure 1, is a
horizontal section (on the line A, B, Figure 2,) and Figure 2, a vertical section.- 1
This mixing meter" consists of a casing a. in the lower part of which is a
moveable diaphragm b,,provided all round its circumference with a flexible piece of
leather c, by which it is attached to the bottom of the chamber d.-The interior of
the space enclosed by this diaphragm b, and leather c, is in communication with
the atmosphere. The diaphragm b, is connected at its centre to the outer end of a 1
spring lever whose position is indicated by the centre line g, the two lines g,
radiating from the common centre or axis of the said lever, shew the range of
motion of the said spring lever.-The tendency of the spring lever g is to press the
diaphragm b, downwards. The lever g is further connected by a link h, to a
rotating valve, in which as well as in the casing j, wherein the valve. i, 2
reciprocates are two ports k, and L, or the arm of the rotating valve i, may be
connected by means of a link direct to the diaphragm b.-The chamber d, is
divided by the plate a3, from the chamber.b³, which is in communication with the
space formed by the diaphragm n, and surrounding leather p.-The link h, and
arm m, and other attachments are divided off from the chamber 63, by the casing c³, s
which opens into the chamber d, below it and allows the. mixture of air and gas
to pass from the end of the valve i, down to the said chamber d, in the direction
of the arrows shewn at Figures 1, and 2.-The diaphragm n, carries at its centre
a conical valve q, working in a seat 7, formed in the vertical tube d³, and operates
so as to control the supply of gas after. the well known manner of a gas governor.-
The gas enters the "mixing meter" through the inlet e³, and passes into the tube d³,
which is closed at the bottom by the plate a³, and the gas, escapes from this tube d³,
around the conical valve q.
}
The action of the apparatus is as follows:-The, pump on the engine when in
operation forins a partial vacuum in the chamber d, by the pump connections, so
that the lower diaphragm b, rises by the pressure of the atmosphere below it and
in rising causes the cylindrical valve i, by means of the connecting link h, to be
rotated to an extent which enables the air and gas ports k, and 1, respectively
therein to be opened and air and gas to be drawn in therethrough in the requisite
"proportions to form an explosive or combustible mixture. The proportions of air
and gas remain constant whether the quantity drawn through the meter is large or
small. The proportions of air and gas are, determined by the areas of the ports'l,
and k, and the proportion of these areas may be altered from time to time as
required by means of an end adjustment. Such an adjustment is shewn at
Figure 1, consisting of the screwed bolt t, attached to the outer end of the
cylindrical valve i, and passing out through the cover u, at the outer end of the
casing. This bolt is provided with the adjusting nut v.
The order of construction of the apparatus hereinbefore described may be inverted
and in place of using the diaphragms and flexible leather connections, pistons
working in cylinders may be substituted but as this modification is so obvious to

page_text: .
a practical constructor of gas measuring apparatus I have not considered it necessary
to illustrate such modification by drawings.
In place of using in the "mixing meter" the rotating valve i, hereinbefore
described I may substitute a valve of the construction shewn at Figures 8, and 9,
Sheet 4, of the Drawings of my Specification N° 180 A.D. 1881, or any other
suitable valvular arrangement.
As regards this part of my said Invention what I consider to be novel and
original and therefore claim as the Invention secured to me by the hereinbefore in
part recited Letters Patent is :-
The mixing meter consisting of a chamber or casing containing a diaphragm so
attached to the chamber or casing that one side of the diaphragm is exposed to the
pressure of the atmosphere and its opposite side is acted upon by a spring lever or
its equivalent the said diaphragm being connected to a rotating valve or its
equivalent in which there are ports for admitting air and gas in the necessary
proportions. The mixing meter being also provided with a second diaphragm or
its equivalent to which a gas regulating valve is attached, the mixing meter
being caused to operate by the reduction of pressure produced therein by the
pump so as to maintain a constant proportion of air and gas in the said mixture
thereof as herein before described and shewn at Figures 1, and 2, of the annexed
Drawings.
My said Invention relates in the second place to the igniting of the mixture of
gas and air which is burned in the cylinders of gas engines. For this purpose
I use a burner or igniter as shewn in longitudinal section at Figure 5, and on an
enlarged scale at Figure 10, of the accompanying Drawings.-This burner or igniter
consists of a short tube x, of fire-clay or other refractory material whose inner end
is perforated or upon or against which may be (as shewn more particularly at
Figure 10,) fastened perforated plates or thin layers of wire gauze y, and through
which the mixture of air and gas issues from a passage leading from a reservoir
containing a compressed mixture of air and gas. This short tube x, has towards
its outer end the piece b¹, projecting from it towards its centre, and the hollow of
the tube x, is of sufficient length or depth to allow of the mixture of air and gas
obtaining an eddying or analogous motion which is caused by the projection b¹, inter-
fering with the direct flow of the mixture of air and gas through the said tube x.―
By this means the ignition of the mixture of air and gas is at all times insured; as
in the event of any temporary interruption of the flow of air and gas the heat of
the projection b', reignites it on the flow being resumed. In this improved igniter
the flow of the mixture of air and gas is a continuous flow but intermittent in
quantity or intensity.-Instead of the projection 6', inside the tube x, more than
one such projection or a ring may be substituted or the flame from the opening of
the igniter may be allowed to play into a cup of fire-clay or other refractory
material or otherwise on a piece of fireclay so as to produce the necessary eddying
action on the current of air and gas.
For the purpose of effecting the initial lighting of the igniter at starting the
engine the cylinder cover c¹, has the hole d, formed in it in communication with
the hole e¹, in the tube x, of the igniter so that a match or its equivalent can be
passed into the hole d', to the mixture of air and gas.-The hole d', is provided
with the screwed plug f¹, or its equivalant for opening or closing it as required.
As regards this part of my present Invention what I consider to be novel and
original and therefore claim as secured to me by the hereinbefore in part recited
Letters Patent is. :-
The burner or igniter. consisting of the tube x, of fire-clay or other refractory
material with..the raised or projecting piece b¹, or its bereinbefore mentioned
equivalents in the hollow of the said tube x..
:-
In carrying out the third part of my present Invention that is to say, for the
purpose of enabling, the use of the igniter herein before described to be dispensed
with after the engine has been working for a short time the end of the piston or
piston attachment 2, Figure 5, is provided with the cup j, of fireclay or other

page_text: :
refractory material in whose lower part is the projection or knob k¹, or several
šmall holes may be formed in the bottom of the cup'j'.-This fireclay cup is by
preference fixed in the plate it, of metal, separated from the piston attachment i,
by.a layer of asbestos .The cup j', when the piston is at the end of its inward
stroke, enters the opening , in the secondary cylinder cover m¹, which has formed
around the said opening 1, the groove n¹, in which a portion of the mixture of air
and gas entering the cylinder has an eddying or analogous motion imparted to it
for the purpose of more completely insuring its immediate ignition:-The cup j¹,
in place of being attached to the piston or piston.attachment 4, may be attached
to the secondary cylinder cover m².
As regards this part of my present Invention what I consider to be novel and
original and therefore claim as secured to me by the hereinbefore in part recited
Letters Patent is :-
First. The means for enabling the burners or igniters of gas engines to be
dispensed with after the said engines have been working for a short time consisting
of the cup j', of fire-clay or other refractory 'material with a projection or several
small holes in its hollow or recess, the said cup j¹, being secured to the end of the
piston or piston attachment or to the cylinder cover m³, and
Second. I also claim the circular groove n', or its equivalent for producing the
eddying of the mixture of air and gas therein substantially as herein before
described.
In carrying out the fourth part of my Invention I apply the second admission
valve o¹, situated as closely as possible to the admission port p¹, leading into the
combustion cylinder g', and this valve o¹, I by preference operate by a rapidly
moving piece of mechanism such as a cam or tappet or its equivalent as shewn at
Figures 12, 13, and 14, in which Figures u³, represents the valve rod carrying at
its end the small wheel v³, which is pressed by means of the spring w³, (Figure 14)
against the cam 23,-The projection on the said cam pushes the valve open and the
spring w³, brings it back to its normal position.-The valve o¹, is prevented from
becoming too hot by the wire gauze arrangement shewn at q', hereinafter described
also by being kept cool by the water casing r¹, surrounding the chamber which
.contains the said valve o'
Instead of the annular space referred to and marked E, in my aforesaid
Specification N° 180 A D. 1881. I place the wire gauze q', or its equivalent in the
admission port p¹, sufficiently far back from the inside face of the cylinder cover c¹,
as to prevent the heat of the combustion in the cylinder g', destroying the wire
gauze q, the port p¹, being made of such area as to ensure ignition taking place
at its inner end during the period when the combustion is most intense, that is to
say that the speed of the gaseous mixture while entering the cylinder will be
greater than the rate at which the flame can burn back through the mixture.-
The port p¹, and gauze q', are also kept cool by means of water circulating through
the casing ¹, surrounding them.-The cylinder.cover c', is further kept cool by the
inner or secondary cylinder cover m¹, separated from the other cover c', by the
layer, of asbestos s', or its equivalent. The port p¹, may be of any shape and
instead of only one port there may be several such ports.
At Figures 3, and 4, I have shewn at g³, the position of a piece of valve
mechanism such as may be used in the carrying out of my present invention, and
at Figures 6, 7, 8, and 9 I have shewn the same detail on an enlarged scale This
valve, mechanism is connected at h³, to the reservoir and at i³, to the lighter and
at 23, to the pump as hereinafter described.-It consists of the chamber ³, into
which the mixture of air and gas passes to the reservoir. which is not shewn on
the Drawings and into which the said mixture is compressed by the pump. From the
chamber, the mixture of air and gas passes through the valve k³, This valve k³,
being opened by the compressing stroke of the pump a', (Figures 12, and 13).—
From this chamber 13, the mixture of air and gas passes through the valve n³, to
the igniter but this only when the pressure in the chamber 1, becomes sufficiently
great from the action of the pump. The constant supply of the mixture of air and

page_text: gas to the igniter is maintained by the flow of the said mixture through the
passage 83, from the chamber 3, which is in direct communication with the
reservoir; the area of this hole 83, being so regulated by the screw to, as to
maintain a small flame, which is increased by the action of the pump through the
valve n³, when the pressure in the pump increases.
In the event of the quantity of air and gas burned in the cylinder g¹, when the
engine is running light or without a load being insufficient to maintain the knob k³,
or its equivalent on the piston or piston attachment or in the secondary cylinder
cover mat a temperature sufficient to ignite the incoming air and gas, provision is
made for automatically re-admitting the mixture of air and gas through the igniter
by means of a valve m³, actuated by the speed governor, this coming into operation
before the temperature has become too low to ignite it.
As regards this part of my present Invention what I consider novel and original
and therefore claim as secured to me by the hereinbefore in part recited Letters.
Patent is:-
First. The arrangement of the second admission valve o¹, situated as close as
possible to the admission port p², and operated by the cam x³, rod u³, and wheel v³,
and their attachments or the mechanical equivalent thereof substantially as,
herein before described and shewn on the accompanying Drawings, and the keeping.
cool of the said valve o', by means of the gauze q', also the tube p¹, arranged as
herein before described to prevent the air and gas burning back upon and destroying,
the wire gauze q¹.
Second. The arrangement for producing the intermittent variation in the
intensity of the flame of the igniter by the means or the mechanical equivalents
thereof substantially as herein before described also the arrangement for re-admitting
the mixture of air and gas through the igniter as and for the purposes hereinbefore
described.
In carrying out the Fifth part of my present invention as represented more
particularly at Figures 3, 4, and 5 respectively in part vertical section and front
elevation, plan and transverse section I construct the rear end portion of the
cylinder, that is to say, the end which contains the admission and exhaust ports in
one piece with the end of the pump a'; these together constituting a casting which
is bolted on to the bed of the sole-plate t¹, of the engine Figures 12, and 13,-The
hot or combustion cylinder g¹, is bolted to this casting and carries at its forward
end the working. cylinder u', which is supported in a guide or guides so that it can
move freely lengthwise with the end wise expansion of the combustion cylinder g',
when that cylinder is hot or contracting by cooling when the engine is not at
work. The guide represented upon the accompanying Drawings more particularly
at Figure 15, consists of the flanged steel collar v¹, through which is passed the
bolt w, and which collar v¹, passes through a slot x, in a snug formed on the
cylinder casting thus allowing the cylinder to move lengthways.
As regards this part of my present Invention what I consider to be novel and
original and therefore claim as secured to me by the herein before in part recited
Letters Patent is :-
Constructing the rear end portion of the cylinder that is to say the end which
contains the admission and exhaust ports in one casting and in one piece with the
end of the pump and bolted on to the bed or sole-plate of the engine, also the
arrangement for end wise expansion and contraction of the combustion cylinder
substantially as hereinbefore set forth with reference to the accompanying
Drawings.
In carrying out the Sixth part of my present Invention, that is to say, for the
purpose of regulating the speed of the engine, the inlet valve o¹, hereinbefore.
described, is caused to shut at different periods of the piston's stroke by the action
of a speed governor shifting either the valve rod u³, across the face of a variable
cam, or shifting a variable cam across the end of the valve rod, and the residue of
the air and gas left in the pump a³, after the valve o¹, is shut, accumulates in the
reservoir until its pressure opens the loaded valve at, and allows the surplus to

page_text: escape back into the pump a¹, during its outward stroke. -Or the speed governor
may be connected so as to operate a valve in the passage between the pump a¹, and
the reservoir so as to allow a portion of the gaseous mixture to pass from the pump
to the reservoir during the compression stroke, and from the reservoir to the pump
during the outward stroke as shewn at m³, Figures 6, 8, and 9.-Or the speed
governor may similarly operate a valve in the passage between the pump a¹, and
the mixing meter" hereinbefore described with reference to Figures 1, and 2, of
the accompanying Drawings.
ct
As regards this part, of my present Invention what I consider to be novel and
original and therefore claim as secured to me by the hereinbefore in part recited
Letters Patent is :-
1
For the purpose of regulating the speed of the engine the shutting of the inlet
valve o¹, at different periods of the piston's stroke by the action of a speed governor
or the connection of the speed governor in such a manner as to operate a valve in
'the passage between the pump and the reservoir or the operating by the speed
governor of a valve in the passage. between the pump and the "mixing meter" as
herein before described.
-
1
In carrying out my present Invention it is to be understood that the aforesaid
several improvements may be used either in combination in a gas engine as shewn
on the annexed Drawings or they may be used separately in other gas engines.
It is to be understood that the mode of operating the engine hereinbefore
described is similar to that described in my Specification N° 180 A.D. 1881..
In Witness Whereof I the said William Foulis have hereunto set my hand and
seal this thirty first day of December in the year of our Lord One thousand eight
hundred and eighty three.
WILLIAM FOULIS. (L.S.)