Improvements in Gas Engines.
Year: 1889

page_text: Date of Application, 28th May, 1889
Complete Specification Left, 28th Mar., 1890-Accepted, 3rd May, 1890
PROVISIONAL SPECIFICATION.
Improvements in Gas Engines.
I, DUGALD CLERK of Driffold Villa Manor Hill, Sutton Coldfield in the County
of Warwick, Engineer, do hereby declare the nature of this invention to be as
follows:-
-:
In most gas or vapour engines as at present constructed to use compression, one
in.pulse is given for every four movements of the piston, or one impulse for every
two revolutions of the crank shaft. In some gas engines an impulse is given for
every revolution; but the fresh charge is generally utilized to discharge the burned'
gases resulting from the previous explosion and although the cylinder may be thus
charged and an explosion obtained for every revolution of the engine, yet there is a
difficulty in completely expelling the burned gases without at the same time losing.
some of the fresh charge at the exhaust ports.
The main objects of this invention are to arrange a gas engine in such manner
that an impulse can be obtained at every revolution, while the charge is admitted
and the exhaust expelled by the positive action of a secondary or displacer piston
working in the same cylinder as the power or main piston; to dispense with explosion
altogether in some circumstances, and so burn the gas or vapour that any desired
power of impulse may be obtained capable of increase or diminution at will as with
the power in steain engines; and to so arrange the linkage by which the secondary
piston is driven from a crank pin, that the proper motion is given to that piston, and
it is caused to pause at the required time.
I am well aware that attempts have been made to construct engines to work with
two pistons in one cylinder; but such attempts have hitherto been failures, mainly
because of improper modes of actuating the secondary piston and failure to give it
the peculiar motion necessary.
In applying my invention to an explosion gas engine having two pistons, I adopt
the following arrangement:-
to me.
The engine contains one cylinder in which two pistons work; the motor piston
is of the common trunk kind working in an open ended cylinder and running
over the exhaust port towards the extremity of its working stroke as in an
engine described in the Specification to Patent No. 1089-1881 previously granted
The other end of the cylinder is closed by a cover, through which a
suitably packed and guided piston rod passes and actuates the secondary piston
within the cylinder. A rocking shaft passes under the cylinder and connects by
a lever, to a crank pin on the crank shaft by a connecting rod. The lever is thus
moved to and fro by the movement of the engine, and a link or rod from that or
another pin in the lever connects to the secondary piston rod guide or crosshead
and so the secondary piston is driven from the crank shaft. The centre of this pin
is arranged with reference to the guide or crosshead that when near one extreme
of its stroke, the crosshead pin, lever pin, and rocking shaft are in the same line, so
that considerable movement of the rocking shaft may occur about the "dead centre
position, while the crosshead or guide and therefore the secondary piston remains
nearly stationary. By allowing a suitable lead or advance position in the direction
of revolution, to the motor piston crank pin; the motor piston after receiving an
impulse moves forward until it uncovers the exhaust ports, meanwhile the secondary
or displacer piston remains almost stationary as its lever and rod move about the
"dead centre "
but when the exhaust ports are uncovered the further movement
causes the displacer piston to move rapidly forward and discharge the exhaust gases.
while it takes in behind it a fresh charge through suitable valves. It moves out till it
approaches near the exhaust port edge, by which time the motor piston has moved.
"

page_text: back to cover those ports, the two pistons then move back at nearly the same rate
until the compression end of the motor piston stroke is nearly reached, when that
piston begins to slow down; but the displacer piston still moves back and the charge
behind it is transferred by suitable valves to the space forming between the pistons.
The displacer piston arrives at the end of its stroke nearly at the same time as the
motor piston and the space between the two forms the explosion space. The mixture
therein may be ignited by any suitable means; but prefer to ignite by an
incandescent tube which opens to the mixture by uncovering a port due to the
movement of the displacer piston.
The motor piston then moves forward under the pressure of the explosion
and the displacer piston remains nearly without movement until the exhaust position
is attained.
The displacer piston linkage is arranged to take the whole pressure of the
explosion, and but little reaches the crank pin, because of the position at the moment
of ignition.
The rocking shaft may carry two levers, one at each side of the cylinders, which
couple to the displacer crosshead, or one lever only may be used and connected by
suitable pins and side guides.
The lever or levers may be driven from a separate crank pin, or the position of the
linkage may be arranged with reference to the power crank so that it may be coupled
to it, and so dispense with the necessity of a second crank pin.
The charge of gas and air may be drawn into the cylinder on one side of the
displacer piston and transferred through suitable valves to the space between the
two pistons when such space is formed by their relative movements, and the governing
of the speed of the engine may be accomplished in any well known way, by cutting off
the gas supply and missing impulses. I prefer, however, to take the air portion of
the charge only into the cylinder during the displacing stroke on one side of the
displacer piston and to take the gas required to form the explosive mixture into a
separate gas pump, which may form, or be part of the displacer piston rod; when the
two pistons return together, the air only is compressed by the displacer piston, and
the gas is separately compressed by the gas pump.
When the displacer piston begins to move away from the motor piston, the valves
are so arranged that gas flows from the gas pump into the air which is being
transferred to the explosion space. An explosive mixture is thus formed between
the pistons, and only there, so that at no time is there any explosive mixture, except
in the explosion space. By this method there is no possibility of back ignition behind
the displacer piston, as only air is there admitted and the explosive charge is not
formed until the moment arrives at which it is required.
When I form my explosive mixture in this way, I govern the engine by lifting, or
opening, or holding open the inlet gas pump valve and then the gas passes to and
fro to the gas bag and back again without discharge; an ignition is thus missed,
because the explosion space contains air alone.
When I apply my invention to the production of motive power from gas without
explosion, I use the arrangement of engine already described; but I modify the
method of forming the mixture and igniting in the following manner :-
I so arrange the valves that some air is first allowed to pass from behind the
displacer piston to the space between the two pistons, that is, the two pistons are first
allowed to move slightly apart on the compression stroke and then the gas under
compression is allowed to stream into the passage through which the compressed air
is passing; it then mixes with it, and is passed by a grating or plate perforated with
holes, and protected by wire gauze to the igniting arrangement, which may consist
of a flame inside the cylinder in the path of the stream from the grating, or any other
well known method; but 1 prefer to use an incandescent tube, heated by a bunsen
flame outside, with its interior communicating by a wile tub, or two smaller tubes
with the cylinder. When I use the wide tube 1 divide the passage in it by a metallic
diaphragm, and cause the first portion of the entering inflammable gases to impinge
on one division and so flow to the incandescent interior of the tube and become ignited.

page_text: When I use the double tube connection I cause the entering mixture to flow against
the opening of one of the tubes. In any case I cause the mixture to ignite whenever
it begins to flow, so that there may be no accumulation of mixture in the combustion
space, and then an ignition or explosion, but that immediately inflammable mixture
passes the grating it ignites and burns as a flame within the cylinder, and heats up
the air or other gases within it. The pressure rises at the end of the stroke by the
movement of the displacer and gas pump pistons; but the pressure of combustion
never exceeds that of the air behind the displacer or the gas in the pump. But the
pressures of the combustion on one side of the displacer and the air on the other
being equal, no work is expended by the engine in raising the pressure, and the motor
piston moves forward under the impulse just as in the case of an explosion. In this
method of applying my invention, I can reduce the power of each impulse by injecting
less flame and so getting a lower pressure of combustion. This may be done by
throttling the gas supply to the gas pump and so causing the pressure in it to reach
that in the motor cylinder at a later period than with full gas. The amount of flame
injected is thereby reduced. Or air may be admitted to the gas pump, and so a more
dilute mixture formed and a feebler flame. By either of these means the impulse
may be given to the motor piston with light or heavy loads.
Such engines when made with a suitable number of cylinders may be arranged to
reverse by slightly modifying the linkage of the displacer pistons to render it adjustable
for revolution in either direction.
Dad th: 9711 1 M... 1990
MARKS & CLERK,
13, Temple Street, Birmingham, Agents for Applicant.
COMPLETE SPECIFICATION.
Improvements in Gas Engines.
I DUGALD CLERK of Driffold Villa, Sutton Coldfield, in the County of Warwick,
Engineer, do hereby declare the nature of this invention and in what manner the same
is to be performed, to be particularly described and ascertained in and by the following
statement :-
In most gas or vapour engines as at present constructed to use compression, one
impulse is given for every four movements of the piston or one impulse for every two
revolutions of the crank shaft. In some gas engines an impulse is given for every
revolution; but the fresh charge is generally utilized to discharge the burned gases
resulting from the previous explosion, and although the cylinders may be thus charged
and an explosion obtained for every revolution of the engine, yet there is a difficulty
in completely expelling the burned gases without at the same time losing some of the
fresh charge at the exhaust ports.
The main objects of this invention are to arrange a gas engine in such a manner
that an impulse can be obtained at every revolution, while the charge is admitted and
the exhaust expelled by the positive action of a secondary or displacer piston working
in the same cylinder as the power or main piston, to dispense with explosion
altogether in some circumstances, and to burn the gas or vapour that any desired
power of impulse may be obtained capable of increase or diminution at will as with
the power in steam engines; and to so arrange the linkage by which the secondary
piston is driven from a crank pin, that the proper motion is given to that piston, and
it is caused to pause at the required time.
I am well aware that attempts have been made to construct engines to work with
two pistons in one cylinder, but such attempts have hitherto been failures, mainly
because of improper modes of actuating the secondary piston and failure to give it the
peculiar motion necessary.
In applying my invention to an explosion gas engine having two pistons, I adopt
the following arrangement:-The engine contains one cylinder in which two pistons
work, the motor piston is of the common trunk kind working in an open endal

page_text: cylinder and running over the exhaust port towards the extremity of its working
stroke as in an engine described in the Specification to, Patent 1809 of 1881
previously granted to me.
The other end of the cylinder is closed by a cover, through which a suitably packed
and guided piston rod passes and actuates the secondary piston within the cylinder.
A rocking shaft passes under the cylinder and connects by a lever to a crank pin on
the crank shaft by a connecting rod. The lever is thus moved to and fro by the
movement of the engine, and a link or rod from that or another pin in the lever,
connects to the secondary piston rod, guide or crosshead and so the secondary
piston is driven from the crank shaft. The centre of this pin is arranged with
reference to the guide or crosshead that when near one extreme of its stroke, the
crosshead pin, lever pin, and rocking shaft, are in the same line, so that considerable
movement of the rocking shaft may occur about the "dead centre" position, while the
crosshead or guide and, therefore, the secondary piston remains nearly stationary.
By allowing a suitable lead or advance position in the direction of revolution, to
the motor piston crank pin; the motor piston after receiving an impulse moves
forward until it uncovers the exhaust ports, meanwhile the secondary or displacer piston
remains almost stationary as its lever and rod move about the "dead centre;" but
when the exhaust ports are uncovered the further movement causes the displacer
piston to move rapidly forward and discharge the exhaust gases, while it takes in
behind it a fresh charge through suitable valves. It moves out till it approaches near
the exhaust port edge, by which time the motor piston has moved back to cover those
ports, the two pistons then move back at nearly the same rate until the compression
end of the motor piston stroke is nearly reached, when that piston begins to slow
down; but the displacer piston still moves back and the charge behind it is transferred
by suitable valves to the space forming between the pistons. The displacer piston
arrives at the end of its stroke nearly at the same time as the motor piston, and the
space between the two forms the explosion space. The mixture therein may be
ignited by any suitable means; but prefer to ignite by an incandescent tube
which opens to the mixture by uncovering a port due to the movement of the displacer
piston.
The motor piston then moves forward under the pressure of the explosion and the
displacer piston remains nearly without movement until the exhaust position is
attained.
The displacer piston linkage is arranged to take the whole pressure of the
explosion, and but little reaches the crank pin because of the position at the moment
of ignition.
The rocking shaft may carry two levers, one at each side of the cylinder, which
couple to the displacer crosshead, or one lever only may be used and connected by
suitable pins and side guides.
The lever or levers may be driven from a separate crank pin or the position of the
linkage may be arranged with reference to the power crank so that it may be
coupled to it and so dispense with the necessity of a second crank pin.
The charge of gas and air may be drawn into the cylinder on one side of the
displacer piston and transferred through suitable valves to the space between the two
pistons when such space is formed by their relative movements, and the governing of
the speed of the engine may be accomplished in any well known way by entting off
the gas supply and missing impulses. I prefer, however, to take the air portion
of the charge only into the cylinder during the displacing stroke on one side of the
displacer piston and to take the gas required to form the explosive mixture into
a separate gas pump, which may form or he part of the displacer piston rod;
when the two pistons return together, the air only is compressed by the displacer
piston, and the gas is separately compressed by the gas pump.
When the displacer piston begins to move away from the motor piston, the valves
are so arranged that gas flows from the gas pump into the air which is being
transferred to the explosion space. An explosive mixture is thus formed between the
pistons, and only there, so that at no time is there any explosive mixture, except in

page_text: the explosion space. By this method there is no possibility of back ignition behind
the displacer piston, as only air is there admitted and the explosive charge is not
formed until the moment arrives at which it is required.
When I form my explosive mixture in this way, I govern the engine by lifting, or
opening, or holding open, the inlet gas pump valve and then the gas passes to and fro
to the gas bag and back again without discharge, an ignition is thus missed, because
the explosion space contains air alone. When I apply my invention to the production
of motive power from gas without explosion I use the arrangement of engine
already described, but I modify the method of forming the mixture and igniting in
the following manner :-
I so arrange the valves that some air is first allowed to pass from behind the
displacer piston to the space between the two pistons, that is, the two pistons are first
allowed to move slightly apart on the compression stroke and then the gas under
compression is allowed to stream into the passage through which the compressed air
is passing; it then mixes with it, and is passed by a grating or plate perforated with
holes and protected by wire gauze, to the igniting arrangement, which may consist
of a flame inside the cylinder in the path of the stream from the grating, or any other
well known method; but I prefer to use an incandescent tube, heated by a bunsen
flame outside, with its interior communicating by a wide tube, or two smaller tubes
with the cylinder. When I use the wide tube I divide the passage in it by a metallic
diaphragm, and cause the first portion of the entering inflammable gases to impinge
on one division and so flow to the incandescent interior of the tube and become
ignited. When I use the double tube connection I cause the entering mixture to
flow against the opening of one of the tubes. In any case I cause the mixture to
ignite whenever it begins to flow so that there may be no accumulation of mixture in
the combustion space, and then an ignition or explosion; but that immediately
inflammable mixture passes the grating it ignites and burns as a flame within the
cylinder, and heats up the air or other gases within it. The pressure rises at the end
of the stroke by the movement of the displacer and gas pump pistons; but the
pressure of combustion never exceeds that of the air behind the displacer or the gas
in the pump.
But the pressures of the combustion on one side of the displacer and
the air on the other being equal, no work is expended by the engine in raising the
pressure, and the motor piston moves forward under the impulse just as in the case
of an explosion. In this method of applying my invention, I can reduce the power
of each impulse by injecting less flame and so getting a lower pressure of combustion.
This may be done by throttling the gas supply to the gas pump and so causing the
pressure in it to reach that in the motor cylinder at a later period than with full gas.
The amount of flame injected is thereby reduced. Or air may be admitted to the
gas pump, and so a more dilute mixture formed and a feebler flame. By either of
these means the impulse may be given to the motor piston with light or heavy
loads.
Such engines when made with a suitable number of cylinders may be arranged to
reverse by slightly modifying the linkage of the displacer pistons to render it adjust-
able for revolution in either direction.
In order that my Invention and the manner of performing the same may be fully
understood & readily carried into effect 1 hereunto append two sheets of explanatory
drawings to be hereinafter referred to.
Figure 1 is a longitudinal section showing an explosion gas engine constructed in
accordance with my Invention. Figures 2, 3 & 4 are longitudinal sections drawn
diagrammatically in order to show the relative positions of the displacer & motor
pistons at different portions of a revolution, together with the corresponding positions
of the linkage actuating the displacer or secondary piston. Figure 5 is a plan in
which the engine is in the same position as in Figure 1. Figures 6 & 7 show on a
larger scale one construction of the displacer piston. Figure 8 is also a section of
the displacer piston in position on a larger scale illustrating one arrangement of a
separate gas pump formed from the piston rod. Figures 9 & 10 are sections illus
trating the application of my invention to engines in which the inflammable gases

page_text: are burned without explosion, that is, the motive power is obtained by injecting flame
into the cylinder, and Figures 1 and 12 are sections of my improved igniting
arrangements as applied to flame engines. Figure 3 is a diagrammatic longitudinal
section showing a modified arrangement of linkage centres. Figure 14 shows another
arrangement of linkage and Figure 15 is a plan illustrating the linkage seen in
Figure 14.
Figure 15 is a diagrammatic section showing an arrangement of linkage by which
the second crank can be dispensed with and the correct motion for the back piston
obtained from the motor crank pin.
Referring to Figure 1, the motor piston A works in the water jacketed cylinder A¹
and connects by the rod A2 to the crank pin B which actuates the crank shaft B¹ and
the displacer disc or crank C. The crank C (plan Figure 5) drives the first lever D
by the connecting rod and the rocking shaft D' to which the lever D is keyed or
otherwise attached, moves the second lever E. This lever E connects by the rod E¹
to the cross head or slide F which is attached to the displacer or secondary piston G
by the piston rod F¹. The crank C and the connecting rod (1 together with the
first lever D are not seen in Figure 1, but their positions are indicated in thick lines
where lettered on Figures 1, 2, 3 & 4.
The action and the arrangement of the engine are as follows:-
In Figure 1 the motor piston A is shown full in, and the charge exists in a com-
pressed state between it and the displacer piston G, the gases are ignited in this
position and the pressure produced by the explosion drives forward the motor piston.
The linkage actuat.ng the displacer is so proportioned that the displacer piston G
remains at, or near the end of the stroke during the greater part of the forward stroke
of the motor piston, that is, until the motor piston passes over the exhaust port H, and
so allows the contents of the cylinder to discharge down to atmospheric pressure.
The displacer piston G then moves out and discharges before it the exhaust gases
through the port H, while it draws into the cylinder a fresh charge of inflammable
gas and air through the gas and air inlet valve I. The two pistons then return
together as close to each other as may be desired without touching, and the charge is
compressed behind the displacer piston G between it and the cylinder cover K. The
inlet gas and air valve I is automatic and closes by spring or gravity immediately the
charge ceases to enter.
As the motor piston approaches the end of its "in" stroke, the displacer piston
moves away from it, the motion being so arranged that the two pistons terminate
their stroke at or near the same time. The compressed charge passes through the
valve L in the piston G, as that piston withdraws from the motor piston, and so
occupies the space between the pistons. As the piston G terminates its stroke, it
uncovers the port G¹ leading to the igniting tube G which may be of any ordinary
construction, and so the charge under compression is fired. The position of the hot
portion of the tube is arranged at such distance from the explosive mixture that a
sufficient delay occurs in the firing to allow the piston G to terminate its stroke and
the valve L to come to rest before the explosion occurs. The piston G may be made
long enough to cover the port G₁ at all positions except when firing is required; but
it may be made shorter than is necessary for this as is the case in Figure 1, because
the compression is very slight, while the port is uncovered, and there is no danger of
ignition until the full compression is attained.
Under the pressure of explosion the motor piston moves forward and the whole
cycle is repeated as hereinbefore described.
In Figure 1 the compression has just been completed and the pistons are in the
igniting position. In Figure 2 the motor piston A has moved a little forward and
the levers D and E are in one extreme position which causes the displacer piston G to
move a little forward as shown. In Figure 3 the motor piston has moved forward
and is just about to uncover the exhaust port, while the levers 1) and E have
changed their positions as indicated and the displacer piston G is just commencing
-its out stroke.
In Figure 3 the motor piston has been moved full out, and has travelled a part of

page_text: its return stroke so that it has just covered the exhaust port H. The piston Ghas
then completed its out stroke discharged the exhaust gases through the exhaust
port H, and taken in its charge of inflammable mixture behind it through the valve I
so that the two pistons are ready to return together. The linkage may be arranged
to leave any desired minimum distance between the pistons A and G during their
return movement; but I prefer to so construct it, that only the necessary
mechanical clearance is allowed in order to discharge the exhaust gases, as completely
as possible.
The action and arrangement of the linkage is clearly shown at Figures 1, 2, 3, 4 & 5.
It is to be noted that it depends for its peculiar properties upon the fact that the
piston G terminates its "in" stroke when the lever E is so placed that the centre of
the pin E the centre of the crosshead pin F2 and the centre of the rocking shaft D'
are all in line as clearly seen in Figure 1. The relative positions of the levers D
and E are so set that this alignment occurs at or near the time when the motor
piston A has completed its "in" stroke. By suitably proportioning the lengths of the
levers D and E and their positions on the rocking shaft D' any desired pause may be
made by the displacer piston G so that it may move but slightly when the motor
piston is performing its working stroke. The movement of the piston G occasioned
by the lever D crossing its centre while moving in the direction indicated by the
arrow in Figure 1 does not cause any loss of power, as any power exerted by the
crank C in driving, is imparted to the piston A, and the piston G in returning to
the end of its stroke again by the return of the lever E to the position of .Figure 1
after occupying that of Figure 2, has pressure exerted upon it and does work on the
crank C.
In this manner the two pistons receive the movement desired, and all the operations
of charging, exhausting, compressing, and igniting, are performed in one cylinder
and without loss of gas at the exhaust ports while an impulse at every revolution is
obtained.
The gas and air inlet valve may be of any known construction and a separate gas
inlet valve may be provided if desired, and the transfer or displacer piston valve may
also be of any usual construction.
The arrangement of valves shown is preferable when the minimum of clearance is
required between the displacer piston and the cylinder cover K, but when the
minimum of such clearance is not required the piston G may be constructed without
a valve, and a passage or port may be arranged in the side of the cylinder communi-
cating between the back and front of the displacer piston. The port may be
controlled by a lift valve such as those shown in Figure 1 or a slide, or piston valve
may be used without departing from the essential features of my invention. I prefer
to pass the inflammable gases direct through the displacer piston; but they may pass
into the space between the pistons by side passages controlled by any known valves
suitable for such purposes.
When the explosion occurs it is confined between the pistons, and the rings in the
displacer piston are of suitable construction and number to make that piston withstand
the explosion pressure equally with the motor piston. Figs. 6 and 7 show on a
larger scale one. construction of displacer piston, and transfer valve, suitable for
The valve L is in this case brought to its seat by a flat spring a, which is
convenient as occupying little space; but any spring may be used or the valve may
be arranged to be vertical so as to seat by its gravity. Figure 6 is a section and
Figure 7 is an end elevation.
use.
Figure 8 illustrates that application of my invention in which the displacer piston
rod is utilized to form a gas pump.
The piston rod F is enlarged at M and fitted with piston rings working in a
chamber or cylinder so that the enlargement serves as a piston. The gas is
admitted to the annular space around the rod F¹ on one stroke by a valve of
ordinary construction and on the return stroke it is compressed; and when the
pressure slightly exceeds that within the main cylinder, the valve within the
enlargement on the rod, lifts, and the gas flows by the passages or holes c d to a

page_text: suitable hole or holes behind the transfer valve L. It then mixes with the air flowing
through that valve, and so explosive mixture is formed only when required and only
in the space between the motor and displacer pistons.
By this method all danger of ignition behind the displacer piston is avoided as no
explosive mixture is formed except where required.
Figure 9 shows one mode of applying my invention to an engine in which the
gases are burned as they enter the motor cylinder instead of being allowed to enter
first in a body and then ignited.
The engine receives its power by combustion not by explosion. A grating such as e
is placed over the valve L in such manner that the gases flowing from that valve can
only pass to the cylinder by passing throngh the grating. The grating is formed by
piercing a metal plate or plates with small holes and backing up those holes with
wire gauze so that explosive gases may burn at the grating without the flame
passing back through the gauze or holes. Such gratings are well understood among
engineers using combustible gases for various purposes and require no further
description. The air and gas mix as I have already described while referring to
Figure 8 and pass through the grating in a mixed state. One or more holes are
bored in an inclined or oblique manner as are seen at Figure 9, and the gases issuing
impinge against the entrance to an igniter tube as g which is heated to incandescence
by an external flame.
The mixture at once ignites and flows into the cylinder as flame.
The valves and pump clearances are so arranged that a portion of air is allowed
to pass from behind the displacer piston to the space forming between it and the
motor piston before gas flows from the pump, and so the flame injected into the
space in the manner I have indicated heats up the air already in the space.
The loss occasioned in the older types of combustion engine by the immediate
contact of the whole flame with the cold cylinder walls is thus avoided. Figure 10
shows another modification of combustion engine, here the grating is caused to form
a projection h, and it works against the cylinder; the gas is compressed in a separate
gas pump N and is injected as shewn by the valve k behind the grating hand mixes
there with the air passing through.
Figures 11 and 12 show forms of igniting tubes suitable for acting in a flame or
combustion engine. In Figure 11 the tube s is wide, and a diaphragm m divides the
port leading to the cylinder into two parts. The gas or gaseous mixture to be
ignited is caused to impinge against one side and it flows into the incandescent
portion and ignites as shown. In Figure 12 the ignition may be effected by
causing the mixture or gas to impinge against one of the arms or passages n, o,
leading to the incandescent portion p and so ignition is effected; but I prefer to
cause the gases to be ignited to be introduced as indicated in Figure 12. The jet of
gas or inflammable mixture r is directed across the tube or nozzle s, and induces a
current which draws a portion of gaseous mixture into the lower tube o, causing it to
fire immediately it comes in contact with the incandescent tube p. These tubes can
be used to ignite the flame without allowing any explosion within the cylinder either
according to the arrangements shown in Figures 8 or 9. The gas pump N Figure 9
may be placed in various positions and driven either from the motor piston or from
the displacer piston crosshead by levers and links.
The general arrangement of the linkage for actuating the displacer piston may be
varied without departing from the essential features of my invention. Thus the
linkage indicated diagrammatically in Figure 13 and similarly lettered to Figure 1
gives the same peculiar motion to the piston G as in Figure 1, and differs from it
only in having the centre of the rocking shaft D' under the centre of the cylinder A¹
instead of above it. In Figure 14 the centre of the rocking shaft is carried under
the outside of the cylinder which necessitates the lever E being double as seen in
plan Figure 15 and the links or crosshead rods E¹ being double instead of single as
in Figure 1. The motion in this case is also the same although the construction is
varied as illustrated in Figures 14 and 15.
J
Figure 16 shows the mode of obtaining this motion from the motor crank pin

page_text: without recourse to a second crank and the arrangement consists of the bell crank
lever O, the rod P, the lever R, and the link S, connecting to the crosshead actuating
the displacer piston. This motion also gives the same peculiarity to the movement of
the displacer piston G as in the previous instances. In all these cases Figures 1, 13,
14, & 16 are in similar positions, that is, the displacer pistons are at the extreme back
of their stroke caused by the levers E being in line with the links or connecting
rods E' as shown on the end of the bell crank lever O, and the rod P in the case of
Figure 16.
The distinctive feature of the linkage in all cases is the arrangement whereby the
termination of the displacer piston stroke is determined by the alignment of a lever
and a link. This allows a pause or limitation of movement of the crosshead while the
lever is crossing the centre and returning again.
rods.
The rocking shaft centre or the bell crank shaft may be either above the cylinder
or below as desired, and the linkage may be modified to suit, and the first and second
levers D and E may be combined in one plate with pins attached for the connecting
In this case the motion must be given to the displacer crosshead by another
lever and link or side guides may be constructed to allow a link from the plate lever
to drive the crosshead; but this method is open to some objections and is only
applicable when the unbalanced pressures upon the displacer piston are slight as in
the case of combustion engines. In these engines constructed as I have hereinbefore
described, the pressure in front and behind the piston is the same or nearly so, and
consequently the thrust upon the displacer crosshead is only that due to the area of
the piston rod. The explosion engine may be governed in any known manner by
cutting off
gas and by missing explosions.
In the combustion engine the impulse is reduced by reducing the amount of gas
admitted to the gas pump, so as to cause the gas contained to attain the pressure in
the main cylinder at a later period. This may be effected by throttling the gas inlet.
A smaller portion of flame is thus injecte: into the motor cylinder.
Vertical or
diagonal engines may be constructed with the linkage and arrangements described.
Having now particularly described and ascertained the nature of my said Inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
(1) A gas or inflammable vapour engine, having in one cylinder, a motor piston
and a charging piston which charging piston expels exhaust gases by one side while
it takes in a gaseous charge on the other side, in which the charging piston is
actuated positively from a crank on the engine shaft by suitable connecting rods and
levers linked together without the use of cams or gear wheels substantially as and for
the purposes hereinbefore described.
(2) In a gas or inflammable vapour engine having in one cylinder a motor piston
and a charging piston, which charging piston expels exhaust gases by one side while
it draws into the cylinder a gaseous charge on the other side, the use of any system
of linkage for actuating the charging piston containing an oscillating lever such as D
and a rod such as E' so arranged that at one position of the vibration of the lever
such as D the lever and rod occupy a straight line through their centres or nearly so,
in order that the charging piston may be caused to pause or move very little during
the working stroke of the inotor piston.
(3) In a gas or inflammable vapour engine having in one cylinder a motor piston
and a charging piston, which charging piston expels exhaust gases by one side while
it draws into the cylinder a gaseous charge on the other side, the use of a system of
linkage for actuating the charging piston such as is shown in Figure 1 comprising
levers D and E, the crank C, connecting rod C', rod such as E', crosshead such as F
for actuating the charging piston G and producing a pause as hereinbefore described
and illustrated by the accompanying drawings.
(4) In a double piston gas engine of the type shown in Figure 1 the construction
and arrangement of a rocking shaft such as D', a lever such as D together with a

page_text: lever such as E connected to a crosshead such as F by a rod or link E¹, the crosshear
working in a suitable slide the whole, linkage being contained and acting within a
portion of the cylinder cover K as shewn in Figures 1 and 13 for the purposes
herein before described and illustrated in the accompanying drawings.
(5) The use of the arrangement of linkage, or linkage centres illustrated in
Figures 14 and 15 as, herein before described with reference to the accompanying
drawings.
(6) The use of the arrangement of linkage or linkage centres illustrated in
Figure 16 as bereinbefore described with reference to the accompanying drawings.
(7) A combustion gas or vapour engine, in which the gases burn as they enter the
combustion space, having two pistons in one cylinder, and acting so that the increase
of pressure or volume occurs during the transfer of the charge from one side of the
charging piston to the other towards the termination of its stroke as and for the
purposes hereinbefore described and illustrated in the accompanying drawings.
(8) The construction and arrangement of igniter tube having a diaphragm as m
illustrated in Figure 11 and hereinbefore described.
(9) The construction and arrangement of igniter tube having two passages as no
in Figure 12 and hereinhefore described.
(10) In a double piston gas or vapour engine of the type shown in Figure 1 the
separate compression of the inflammable gas and air and the formation of the
inflammable mixture, at, or near the transfer valve, so that explosive or combustible
mixture is formed only when and where required and all risk of explosion behind
the charging piston such as G is obviated as and for the purposes, hereinbefore
described.
Dated this 27th day of March 1890
MARKS & CLERK,
13, Temple Street, Birmingham, Agents for Applicant.