IMPROVEMENTS IN GAS MOTOR ENGINES
Year: 1877

page_text: LETTERS PATENT to Francis William Crossley and William John Crossley, both
of Great Marlborough Street, Manchester, in the County of Lancaster, for the
Invention of "IMPROVEMENTS IN GAS MOTOR ENGINES." Partly a commu-
nication from abroad by Nicolaus August Otto, of Deutz, in the German
Empire.
Sealed the 24th July 1877, and dated the 4th June 1877.
PROVISIONAL SPECIFICATION left by the said Francis William Crossley
and William John Crossley at the Office of the Commissioners of Patents on
the 4th June 1877.
FRANCIS WILLIAM CROSSLEY and WILLIAM JOHN CROSSLEY, both of Great
Marlborough Street, Manchester, in the County of Lancaster. "IMPROVEMENTS IN
GAS MOTOR ENGINES." [Partly a communication from abroad by Nicolaus August
Otto, of Deutz, in the German Empire.]
Our Invention relates to motor engines of the kind in which a piston in a cylinder
is moved by the pressure resulting from the combustion of a mixture of air and
inflammable gas or vapour admitted into the cylinder or compressed therein.
In engines of this kind it has been usual to employ a slide for governing the
passages for the admission of the inflammable mixture and the kindling flame, and
sometimes also for the emission of the products of combustion, such slide having
passages through it, and being kept up to the cylinder face by a spring sufficiently
strong to resist the pressure in the cylinder, and it has been found that with slides
of this kind there is considerable disadvantage resulting from the friction and wear
caused by the constant pressure of the spring. To remedy this evil, we so arrange
the slide that during the working stroke of the engine the gaseous pressure inside
the cylinder itself is caused to press the slide against the face on which it works
with sufficient force to prevent the escape of gas through the port; while at other
times the slide is only kept up to its face by a light spring.
Various arrangements may be adopted for operating according to this method;
thus according to one arrangement we form the slide without the usual flame
passages through it from side to side, such flame passages being formed on one side
Price 1021

page_text: of the slide only. The slide is constantly kept up to the cylinder by a very light
spring sufficient to prevent leakage when there is little or no excess of pressure in
the cylinder, but in order to counteract the pressure exerted on the slide when the
pressure in the cylinder is considerable, a cavity is provided in the slide face furthest
from the cylinder port, in which is fitted an equilibrium cap or ring that bears against 5
the slide cover, and a communication is established between the said cavity and
the inner part of the cap or ring, so that the gaseous pressure in being trans-
mitted froin the cylinder port into such space causes the equilibrium cap to be
pressed against the slide cover, while. the slide is at the same time pressed
firmly against the cylinder face. Or the gascous pressure might be admitted to I
a space between the slide face and the slide cover enclosed within an equilibrium
ring pressed by springs against the latter.
By forming the flame passages on one side of the slide only, a further advantage
is obtained, namely, that by placing the lighting flame between the slide and the
cylinder, as may with this arrangement be done, instead of outside the slide as.1
heretofore, the gas fittings formerly attached to the cover of the slide can now be
attached to the cylinder and so need not be disconnected when the cover is
removed.
Again, instead of fitting such an equilibrium cap or ring in the slide, we in some
cases provide a small cylinder communicating with the main or working cylinder :
and fitted with a piston jointed to one arm of a lever, the other arm of which is
jointed to or presses on the back of the slide cover. Thus, when there is in the main
cylinder excess of pressure tending to force the slide away from the cylinder face,
the like pressure acting on the piston in the small cylinder tends to force it out-
wards, and thus by means of the lever applies préssure to the back of the slide cover s
forcing the slide against the cylinder face. The said small cylinder may also be
applied to press directly against the cover without the intervention of any lever.
And lastly, the same object may be attained by forming the cylinder face on which
the slide works as a loose plate with a prolonged cylindrical boss on its back. The
end of the cylinder is bored out to fit the said boss, which slides in it gas tight, being
packed with rings like an ordinary piston, and which has formed within it the inlet
port for the gas and air. When this plan is used the slide cover is bolted firmly to
the cylinder, and the pressure from within the cylinder forces the loose cylinder faco
tightly against the slide and the slide in its turn against the cover.
When there is no pressure in the cylinder the loose face is held out against the
slide by springs placed at either side of it or in any other convenient way.
According to any of these arrangements the objectionable friction of the slide
occurs only when there is excess of pressure in the main cylinder, or does not occur
at all.
In some engines of the kind referred to, such as are described in the Specification
to Abel's Patent, No. 2081 of 1876, the gas supply valve is opened by means of a
cam on a rotating shaft; and this cam has been fitted to slide on the shaft under the
control of the governor so as to avoid opening the gas supply when the engine
worked at too great a speed.
We modify this arrangement by keeping the cam stationary on the shaft, and
providing a sliding roller on the lever, which works the gas valve. On this roller
is a collar embraced directly by a fork on the governor rod, so that by the action of
the governor the roller can be moved to and fro either to face the cam when the
speed of the engine is normal, or to be moved out of reach .on: the opposite side of
the cam when the engine stops.
In the gas engine described in the before-mentioned Specification, No. 2081
of 1876, a charge of explosive gaseous mixture (containing only such a proportion
of air as is necessary to effect the combustion of the combustible gas) was admitted
to the cylinder separate from a charge of air in such a manner that the explosive
mixture existed in a more or less. undiluted state in aud near the inlet port, while
forward of that point the explosive mixture became more and more diluted by
admixture with the previously introduced air, so that on ignition the combustion of

page_text: the charge took place rapidly at first, and then proceeded more and more slowly as
it extended forward. It has been found that this stratified condition of the com-
bustible charge is prejudicially affected if the peculiar taporing form of the cylinder
described in the said Specification be departed from, as also if the speed of the
engine be varied. Now according to our present Invention we dispense with the
said stratified condition of the combustible charge, and introduce into the cylinder a
uniformly. diluted combustible charge, that is, combustible gas mixed uniformly
with a greater proportion of air than is necessary for its perfect combustion, so that
the entire charge is of a slow burning nature. If such a charge were ignited in
the ordinary way, either by a small gas flaine or by an electric spark, its com-
bustion would take place more slowly than in the stratified condition, where tho
first portion of the charge burns with considerable energy, and therefore, in order to
obtain a sufficiently rapid ignition of such a uniformly diluted charge for the
effective working of the engine, we introduce into a special chamber or passage com-
municating with the cylinder and lighting flame a strong or undiluted charge of
the explosive compound, so that on ignition of this strong charge the resulting flamo
will be projected with some force from such chamber into the cylinder, and in thus
being brought into extended contact with the diluted charge therein will effect its
rapid combustion and will cause the maximum pressure of the gases to be attained
before the piston has performed any considerable part of its stroke.
In ongines operating according to the above-described method the charges of
diluted or undiluted explosive mixture may be introduced into the cylinder
either at atmospheric or higher pressure, or the compression of the gases may
be effected in the cylinder itself as described in the before-mentioned Specification,
No. 208170
According to one arrangement for carrying out the above-described method of
operating we dispense with the tapering form of the end of the cylinder described in
the before-mentioned Specification, and we form at the end of the cylinder a long
narrow chamber communicating at one end with the inlet port, and at the other end
with the cylinder, and by preference made to project centrally somewhat into the
end of the cylinder.
.
-
With this form of cylinder and chamber the before-described charge may be
produced by first admitting a charge of air into the cylinder, and then a charge of
strong combustible compound, the first portion of which in entering the cylinder
will on account of the before-mentioned projecting form of the chamber be pro-
jected centrally into the charge of air and so mix uniformly therewith, producing
the uniformly diluted charge before mentioned, while the last portion of the strong
combustible compound remaining in the passage will form the before-mentioned
strong charge. We prefer, however, to produce the said charge without first intro-
ducing a charge of air by so forming the cam on the engine shaft that actuates the
gas valve that during the greater part of the time during which the combustible
chargo is being introduced into the cylinder the gas valve is only slightly opened,
thus allowing only a small proportion of combustible gas to pass in together with
the air sufficient to form the weak or diluted charge, while when the cylinder has
received its charge the gas valve is opened to a greater extent so as to allow a
greater proportion of combustible gas to mix with the air, and thus to fill the
chamber of the cylinder with the strong charge.
In the above-described mode of operating, by varying the proportions existing
between the strong and diluted explosive charges the combustion may be made to
take place slower or quicker, and thus the duration of combustion be adjusted to
the required speed of the piston.
In the Specification of Patent, No. 491 of 1877, granted to N. A. Otto and F. W.
Crossley, we propose to remedy the difficulty of introducing a lighting flame which
is burning in a valve chamber at atmospheric pressure into a cylinder port where
the pressure is in excess of the atmosphere by establishing an equilibrium of
pressure between the slide chamber and the cylinder a little previously to the
opening of the slide to the cylinder.

page_text: It is now proposed to adopt another method of introducing the said light, viz.,
by so forming the orifice of the chamber in the slide that on approach to the port
in the cylinder the first admission of the compressed gas shall not tend to force the
lighted gas back into its supply pipe, which supply pipe contains no oxygen to
support combustion. To effect this we form a channel in the slide connected with 5
that side of the lighting chamber which first comes in contact with the port, and
projecting from the lighting chamber towards the cylinder port. At the end of
this channel furthest from the lighting chamber we connect the gas supply which
feeds the flame in the chamber. The gas will not, however, burn in this channel,
but will previously to ignition flow into the lighting chamber. On connection 1
being formed between the channel and the cylinder the compressed gases will be
introduced behind the flame and so will not tend to extinguish it by forcing it
back up the supply pipe.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Francis William Crossley and William John Crossley in the Great
Seal Patent Office on the 3rd December 1877.
FRANCIS WILLIAM CROSSLEY and WILLIAM JOHN CROSSLEY, both of Great
Marlborough Street, Manchester, in the County of Lancaster. "IMPROVEMENTS IN
GAS MOTOR ENGINES." Partly a communication from abroad by Nicolaus August
Otto, of Deutz, in the German Empire.
Our Invention relates to motor engines of the kind in which a piston in a
cylinder is moved by the pressure resulting from the combustion of a mixture of air
and inflammable gas or vapour admitted into the cylinder, either at atmospheric or
higher pressure, or compressed therein.
In engines of this kind it has been usual to employ a slide for governing the
passages for the admission of the inflammable mixture and the kindling flame, and
sometimes also for the emission of the products of combustion, such slide having
passages through it, and being kept up to the cylinder face by a spring sufficiently
strong to resist the pressure in the cylinder, and it has been found that with slides
of this kind there is considerable disadvantage resulting from the friction and wear
caused by the constant pressure of the spring. To remedy this evil we so arrange
the slide that during the working stroke of the engine the gaseous pressure inside
the cylinder itself is caused to press the slide against the face on which it works
with sufficient force to prevent the escape of gas through the port, while at other
times the slide is only kept up to its face by a light spring.
Various arrangements may be adopted for operating according to this method;
thus according to one arrangement we form the slide without the usual flame
passages through it from side to side, such flame passages being formed on one side
of the slide only. The slide is constantly kept up to the cylinder by a very light
spring, sufficient to prevent leakage when there is little or no excess of pressure in
the cylinder; but in order to counteract the pressure exerted on the slide when the
pressure in the cylinder is considerable, a cavity is provided in the slide face farthest

page_text: from the cylinder port, in which is fitted an equilibrium cap or ring that bears
against the slide cover, and a communication is established between the said cavity
and the cylinder port and the inner part of the cap or ring, so that the gaseous
pressure in being transmitted from the cylinder port into such space causes the
equilibrium cap to be pressed against the slide cover, while the slide is at the same
time pressed firmly against the cylinder face. Or the gaseous pressure might be
admitted to a space between the slide face and the slide cover enclosed within an
equilibrium ring pressed by springs against the latter.
By forming the flame passages on one side of the slide only a further advantage
is obtained, namely, that by placing the lighting flame between the slide and the
cylinder, as may with this arrangement be done, instead of outside the slide as
heretofore, the gas fittings formerly attached to the cover of the slide can now
be attached to the cylinder and so need not be disconnected when the cover is
removed.
Again, instead of fitting such an equilibrium cap or ring in the slide we in some
cases provide a small cylinder communicating with the main or working cylinder
and fitted with a piston jointed to one arm of a lever, the other arm of which is
jointed to or presses on the back of the slide cover. Thus when there is in the
main cylinder excess of pressure tending to force the slide away from the cylinder
face, the like pressure acting on the piston in the small cylinder tends to force it
outwards, and thus by means of the lever applies pressure to the back of the slide
cover, forcing the slide against the cylinder face. The said small cylinder may
also be applied to press directly against the cover without the intervention of any
lever.
And lastly, the same object may be attained by forming the cylinder face on
which the slide works as a loose plate, with a prolonged cylindrical boss on its back.
The end of the cylinder is bored out to fit the said boss, which slides in it gas-tight,
being packed with rings like an ordinary piston, and which has formed within it
the inlet port for the gas and air. When this plan is used the slide cover is bolted
firmly to the cylinder, and the pressure from within the cylinder forces the loose
cylinder face tightly against the slide, and the slide in its turn against the cover.
When there is no pressure in the cylinder the loose face is held out against the
slide by springs placed at either side of it, or in any other convenient way.
According to any of these arrangements the objectionable friction of the slide
occurs only when there is excess of pressure in the main cylinder, or does not occur
at all.
Figs. 1 to 5 of the accompanying Drawings shew various arrangements for
carrying out our before-described improvement. Figs. 1, 2, and 3 shew respectively
an end view of the engine cylinder with the slide cover removed, a sectional plau
on line X, X, Fig. 1, and a vertical section on line Y, Y, Fig. 2.
A is the end plate of the cylinder; B is the port; C, the slide, actuated by the
orank D on the shaft D¹ by the rod E, as described in Patent No. 2081 of 1876.
The inlet passage for air F, as also that for gas G, and the cavity H containing the
gas jet I, and the holes I¹ for the admission of air into the slide cavity, are all
formed in the cylinder end itself, or in a plate bolted thereto, as shewn, as is also
the channel K through which the slide cavity is charged with the gas required for
the igniting jet or flame. Hence all the openings in the slide communicating with
these several passages can be formed on the inner face of the slide instead of
extending through to the back of the slide, as was the case with some of them in
the previous arrangements; L is the passage establishing communication between
the port B and air passage F, and also with the gas passage G through small holes L'.
M is the slide cavity containing the igniting charge and communicating with the
gas jet I and air passage I, and with the gas channel K by the passage M. N is
a passage formed through the slide, and enlarged at the back into a circular recess,
as shewn, into which is fitted a cap N', the back surface of which bears against the
slide cover O, which, in this case, is bolted firmly to the cylinder end. The slide

page_text: fits loosely into the space between the cover and the cylinder face, and at the same
time when there is no charge in the cylinder it is held lightly against the latter by
means of springs N2, which press the cap N¹ outwards against the cover, and also
by one or more springs O¹ in the slide cover pressing the slide against the cylinder
face. From the side of the cylinder port B a channel B' formed in the cylinder face
extends some distance towards the passage N, so that when the slide has moved
sufficiently to the right hand to bring the passage N in communication with the
channel B, the gaseous pressure existing in the cylinder will be transmitted through
N to the recess at the back of the slide, so as to press the cap N¹ against the slido
cover and the slide itself against the cylinder face, the pressure with which the slide
is kept up to the cylinder face being in proportion as the area at the back of the
valve enclosed by the cap is in excess of the area of the port and channel B, B¹,
and also the opening of the lighting passage B².
The above described position of the slide, when B₁ commences to communicate
with N, corresponds with that position of the engine piston in which it just begins
to perform its in stroke for compressing the gaseous charge drawn in by the previous
out stroke, and it will be seen by the relative positions of the passage N and the
lighting cavity M that the communication between the cylinder port and back of
the valve is maintained during the firing of the gaseous charge and the ensuing
out stroke of the piston, the pressure upon the back of the valve increasing as
the pressure inside the cylinder increases, and decreasing again as the latter
diminishes, so that when the pressure in the cylinder is reduced to that of the
atmosphere again, the slide will only be held to its face by the action of the springs,
as before described, and thus all unnecessary friction during its motion at such
time will be obviated. The cap N1 is made to fit gas-tight in the recess by means
of suitable packing rings.
Fig. 4 shews a cross section of a somewhat modified arrangement of the slide.
In this case a ring N¹ is substituted for the cap of the previous arrangement, the
ring being pressed by springs N2 gas-tight against the slide cover O, and the gaseous
pressure being admitted from the cylinder to the enclosed space at the back of the
slide through the passage N, so as to press the slide against the cylinder face as
before.
Fig. 5.shews an arrangement in which the face A', against which the slide C
works, is formed as a plate separate from the cylinder, having a cylindrical boss A³
fitting as a piston gas-tight into a corresponding cylindrical hole in the cylinder,
the port B being formed in such cylindrical boss. Thus when gaseous pressure
exists in the cylinder, such pressure being exerted against the end surface of the boss
A2, will cause the plate A¹ to press against the face of the slide, thereby pressing
the back of the latter against the cover O.
Another arrangement is shewn at Figs. 6 and 7, which represent respectively a
part longitudinal section and part sectional plan of a gas engine. In this case a
small cylinder P at the top of the cylinder A communicates with the interior of the
latter by a passage P₁, and contains a piston P, which is connected by a link P³. to
one end of a lever P'. The other end of this lever is pivotted to a rod fixed to the
cylinder, as shewn, and at an intermediate point it is connected to a bridge piece 0
on the slide cover O, the latter being in this case not, fixed rigidly to the cylinder,
but bearing against the back face of the slide. Thus on the gaseous pressure in the
cylinder rising above that of the atmosphere, the piston P2 is pressed outwards, and
is thus caused, by means of the link P³ and lever P; to press the cover O against
the slide, and the latter against the cylinder face. During the time when the
pressure in the cylinder does not exceed that of the atmosphere, the slide is merely
held up against the cylinder, face by means of a light spring P5 acting on the link
P and lever P..
In some engines: of the kind before referred to, such as are described in the
Specification to Patent No. 2081 of 1876, the gas supply valve is opened by means
of a cam on a rotating, shaft, and this cam has been fitted to slide on the shaft under

page_text: the control of the governor, so as to avoid opening the gas supply when the engine
worked at too great a speed. We modify this arrangement by keeping the cam
stationary on the shaft, and providing a sliding roller on the lever which works the
gas valve. On this roller is a collar embraced directly by a fork on the governor
rod, so that by the action of the governor the roller can be moved to and fro either
to face the cam when the speed of the engine is normal, or to be moved out of
reach on the opposite side of the cam when the engine stops.
This arrangement is shewn at Figs. 1 and 2. Q is the cam on the shaft D¹ acting
on the roller R of the lever R¹ that works the valve G¹ in the gas passage G.
The lever R¹ has a pin R on which the roller R is free to slide, the latter being
moved by the fork S connected to the governor either so as to face the cam Q, or
into the position shewn on the Drawing in which the cam cannot act upon it.
In the gas engine described in the before-mentioned Specification, No. 2081 of
1876, a charge of explosive gaseous mixture (containing only such a proportion of
air as is necessary to effect the combustion of the combustible gas) was admitted to
the cylinder separate from a charge of air in such a manner that the explosive mixture
existed in a more or less undiluted state in and near the inlet port, while forward of
that point the explosive mixture became more and more diluted by admixture with
the previously introduced air, so that on ignition the combustion of the charge took
place rapidly at first, and then proceeded more and more slowly as it extended
forward.
It has been found that this stratified condition of the combustible charge is
prejudicially affected if the peculiar tapering form of the cylinder described in the
said Specification be departed from, as also if the speed of the engine be varied.
Now according to our present Invention we dispense with the said stratified
condition of the combustible charge, and introduce into the cylinder a uniformly
diluted combustible charge, that is, combustible gas mixed uniformly with a greater
proportion of air than is necessary for its perfect combustion, so that the entire
charge is of a slow-burning nature. If such a charge were ignited in the ordinary
way, either by a small gas flame or by an electric spark, its combustion would take
place more slowly than in the stratified condition, where the first portion of the
charge burns with considerable energy, and therefore in order to obtain a sufficiently
rapid ignition of such a uniformly diluted charge for the effective working of the
engine, we introduce into a chamber or passage cominunicating with the cylinder
and lighting flame a strong or undiluted charge of the explosive compound, so that
on ignition of this strong charge the resulting flame will be projected with some
force from such chamber into the cylinder, and in thus being brought into extended
contact with the diluted charge therein will effect its rapid combustion, and will
cause the maximum pressure of the gases to be attained before the piston has
performed any considerable part of its stroke.
In engines operating according to the above-described method, the charges of
diluted or undiluted explosive mixture may be introduced into the cylinder either
at atmospheric or higher pressure, or the compression of the gases may be effected
in the cylinder itself, as described in the before-mentioned Specification, No. 2081.
According to one arrrangement for carrying out the above-described method of
operating, we dispense with the tapering form of the end of the cylinder described
in the. before-mentioned Specification, and we form at the end of the cylinder a long
-narrow chamber communicating at one end with the inlet port, and at the other
end with the cylinder, and by preference made to project centrally somewhat into
the end of the cylinder.
With this form of cylinder and chamber the before-described charge may be
produced by first admitting a charge of air into the cylinder, and then a charge of
strong combustible compound, the first portion of which in entering the cylinder will,
on account of the before-mentioned projecting form of the chamber, be projected
centrally into the charge of air, and so mix uniformly therewith, producing the
uniformly diluted charge before mentioned, while the last portion of the strong

page_text: combustible compound remaining in the passage will form the before-mentioned
strong charge. We prefer however to produce the said charge without first
introducing a charge of air, by so forming the cam on the engine shaft that actuates
the gas valve, that during the greater part of the time during which the combustible
charge is being introduced into the cylinder, the gas valve is only slightly opened,
thus allowing only a small proportion of combustible gas to pass in together with
the air sufficient to form the weak or diluted charge, while, when the cylinder has
received its charge, the gas valve is opened to a greater extent, so as to allow
a greater proportion of combustible gas to mix with the entering air, and thus to
fill the chamber of the cylinder with the strong charge.
In the above-described mode of operating by varying the proportions existing
between the strong and diluted explosive charges the combustion may be made to
take place slower or quicker, and thus the duration of combustion be adjusted to
the required speed of the piston.
Figs. 6 and 7, and the end view at Fig. 8, shew a construction of the engine
suitable for the above-described method of operating. The port or passage B through
which the charge is introduced is made of considerable length so as to constitute a long
narrow chamber for containing the strong charge before referred to, the inner end
thereof being by preference made to project into the cylinder, as shewn, for a purpose
to be presently mentioned. The passage L, through which air and gas enter the
cylinder from the ports F and G, being in position so as to establish the communi-
cation between the latter and the cylinder port B, and the gas valve G¹ being open,
gas and air enter the cylinder during the out stroke of the piston. Owing however
to the cam actuating the lever R of the gas valve being formed with only a
slight projection on the greater portion of its length, as shewn at Fig. 8, the gas valve
is only slightly opened, and consequently only a small proportion of gas enters with
the air during nearly the whole of the stroke, thus forming the weak or diluted charge
above referred to. Owing to the gas entering the passage L through a number of
small holes it becomes uniformly mixed with the incoming air, and in entering the
cylinder in the form of a jet, through the projecting mouth of the passage B, the
combustible compound becomes uniformly mixed with the portion of the gaseous
product of combustion remaining in the cylinder behind the piston from the previous
charge, thus forming a uniform weak or diluted combustible charge. Towards the
end of the out stroke the cam Q, by means of its raised extremity Q¹, lifts the gas
valve full open, so that a greater proportion of the gas now enters with the air, thus
filling the chamber B with the strong or explosive charge before mentioned. On
firing this charge the flame is projected with force centrally into the diluted charge
in the cylinder, and in thus being brought into extensive contact therewith effects
its proper ignition, as above described.
In the Specification of Patent No. 491 of 1877, granted to N. A. Otto and F. W.
Crossley, we proposed to remedy the difficulty of introducing a lighting flamo which
is burning in a valve chamber at atmospheric pressure into a cylinder-port where
the pressure is in excess of the atmosphere by establishing an equilibrium of pressure.
between the slide chamber and the cylinder a little previously to the opening of the
slide to the cylinder. It is now proposed to adopt another method of introducing
the said light, viz., by so forming the orifice of the chamber in the slide that on
approach to the port in the cylinder the first admission of the compressed gas shall
not tend to force the lighted gas back into its supply pipe, which supply pipe.contains
no oxygen to support combustion. To effect this we form a channel in the slide
connected with that side of the lighting chamber which first comes in contact with
the port, and projecting from the lighting chamber towards the cylinder port. At
the end of this channel furthest from the lighting chamber we connect the gas supply
which feeds the flame in the chamber. The gas will not however burn in this
channel, but will previously to ignition flow into the lighting chamber. On con-
nection being formed between the channel and the cylinder the compressed gases
will be introduced behind the flame, and so will not tend to extinguish it by forcing
it back up the supply pipe.

page_text: Figs. 7 to 12 shew the above-described construction of the slide, Figs. 9 to 12
shewing respectively views of the inner and outer faces of the slide and of the
inner face of the slide cover, and a transverse section through the slide. The cavity
M of the slide, containing the lighting charge, has at its side a channel M' extending
towards the port B of the engine, and at the end of this channel a passage M* is
formed through to the back of the slide, so as to communicate with the channel 0°
formed in the slide cover O, into which gas is adinitted through the pipe O³, so that
as long as the passage M² is in. coinmunication with O2 gas will pass into the cavity
M through M and M. When the cavity M approaches the port B the communi-
ention between M² and O2 is first intercepted, as shewn in Fig. 7, and the channel M'
then communicates with the port B, thus allowing the gaseous pressure in the
cylinder to be transmitted to the charge in the cavity M just before the latter com-
municates directly with the port B.
This arrangement might also be adapted to the forms of slides shewn at Figs. 1 to 4,
instead of the arrangements for the same purpose there shewn, which are similar to
those described in the Specification to our previous Patent, No. 491 of 1877, and
therefore require no further description.
Having thus described the nature of our Invention, and in what manner the same
is to be performed, we claim,-
First. The method substantially as herein described of supplying and igniting the
combustible charge of a gas motor engine, that is to say, making the greater part of
the said charge consist of uniformly mixed combustible fluid so diluted that its
combustion is of a non-explosive character, and igniting the same by means of an
inflamed charge of stronger or less dilute combustible fluid projected from a separate
chamber or passage into it, so as to come into extensive contact therewith.
Second. In a gas motor engine supplied with combustible charge in the manner
above referred to, making the inlet port of the engine as a long narrow passage
projecting centrally into the body of the cylinder, so as to effect the more complete
admixture of the fluids composing the dilute charge, and to constitute the chamber
containing the strong charge, substantially as herein described.
Third. In a gas motor engine effecting the close contact between the slide and
the face on which it works by means of the gaseous pressure of the charge in the
cylinder, so that the slide is relieved of pressure when close contact is not required,
substantially as herein described.
Fourth. In a gas motor engine in which a compressed combustible charge in
the cylinder is kindled by means of an igniting flame in a cavity or chamber in the
slide, providing a channel extending from the side of such cavity nearest the cylinder
port towards the latter, in order to permit the gascous pressure in the cylinder to be
transmitted to the cavity without forcing the igniting flame back up the supply
pipe, and so preventing ignition, substantially as herein described.
Fifth. In a gas motor engine wherein the gas supply valve is worked by a cam
acting on the valve lever, arranging the roller on such lever to slide on its pin, and
connecting it to the governor, so that the roller is moved by it either so as to face
the cam, or so as to be entirely to one side thereof, substantially as and for the
purpose herein described.
Sixth. In a gas motor engine establishing a communication between the interior
of the cylinder and an enclosed space at the back of the valve, so that the gaseous
pressure in the former may be transmitted to the back of the latter, substantially as
and for the purpose herein described.
Seventh. In a gas motor engine constructing the face on which the slide works
separate from the cylinder, and with a piston-like projection fitting a hole in the
cylinder, so that the gaseous pressure in the cylinder will press the said loose face
against the slide, substantially as and for the purpose herein described.
Eighth. In a gas motor engine providing a small cylinder communicating with the
main cylinder, and having a piston connected to the valve cover, so that the gaseous
pressure in the main cylinder will cause the piston of the small cylinder to

page_text: press the slide cover against the slide, and the latter against the cylinder face, sub-
stantially as and for the purpose herein described.
In witness whereof, we, the said Francis William Crossley and William John
Crossley, have hereunto set our hands and seals, this First day of December,
in the year of our Lord One thousand eight hundred and seventy-seven.