Improvements in Gas Engines.
Year: 1894

page_text: Date of Application, 10th July, 1894-Accepted, 11th Aug., 1894
COMPLETE SPECIFICATION.
Improvements in Gas Engines.
I GEORGE CROYDON MARKS of 18 Southampton Buildings London W.C.
County of Middlesex Consulting Engineer and Patent Agent a communication
from Feodor Hirsch of Steinway in the County of Queens, and State of New
York, United States of America, Mechanical 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 :-
The main objects of my invention are avoidance of concussion and vibration
and the utilization of the power ordinarily wasted by such concussion; the pro-
duction of a more powerful engine for a given size and weight; simplification in
the construction and arrangement of parts; a perfectly balanced engine; improved
means for automatically governing the speed of the same; and improved means for
applying the engine with gas when a carburetter is used.
A distinguishing feature of my invention consists in the special construction of a
gas engine having a duplex open-ended power cylinder with a central gas and
firing port, two trunk pistons in said cylinder pivotally connected by rods directly
to the ends of two rock levers, the opposite ends of said rock levers being connected
by pitmans directly to radially opposed cranks upon a common power shaft,-all the
parts being arranged in a common central plane of action coincident with that of
the longitudinal axis of the power cylinder, so that the force of the explosion of
gas between the two cylinders is counterbalanced and equally distributed and
transmitted to the cranks on the power shaft.
Constructed according to my invention an engine may be made much more compact
as a whole and is especially adapted for use as a motor for boats, vehicles, &c., and
for household purposes. Owing to the perfect balance obtained in and between the
operative parts it is practically free from vibration so that it may be employed
industriously or otherwise without the provision of a special foundation, without fear
of imparting a jarring or trembling motion to the structure.
In the accompanying drawings I illustrate the practical embodiment of my
invention in a gas engine in which a carburetter is used, although I do not
confine myself to the use of a carburetter, since any source of gas supply may.
be rendered available; neither do I limit myself to the identical form and
structure of parts shown since it is obvious that variations may be made in
detail without departing from the spirit and intent of my invention.
Figure 1, is a plan of my improved gas engine ;
Figure 2, is a front elevation of the same;
Figure 3, an elevation taken from the left end of the engine;
Figure 4, an elevation of the rear of the engine partially in section ;
Figure 5, a central vertical longitudinal section;
Figure 6, a central vertical section on line u, u, Figure 1;
Figure 7, is a transverse section upon plane of line v, v, Figure 1 ;
Figure 8, is a horizontal section through the rocking levers, upon plane of
line wo, w, Figure 5, showing the pitmans and cranks in elevation;
Figure 9, is an end elevation of the crank shaft ;
Figure 10, is a sectional elevation of a portion of the rear of the engine, showing
the hydro-carbon feeder and the air pump;
Figure 11, is an elevation of the mixer valve disc;
Figure 12, an elevation of the end of the mixer tube, showing the valve openings ;
Figure 13, a section upon plane of line x, x, Figure 6, looking towards the mixer
valve dise

page_text: Figure 14, is a similar view upon plane of line y, y, Figure 6 ;
Figure 15, is a sectional view of the lower portion of the hydro-carbon feeder;
Figure 16, a transverse section of the relief cam M, on the rear of the cam shaft;
Figure 17, is a vertical section of the valve chest upon plane of line 1, 1, Figure 18,
showing the ignitor and the gas exhaust valves;
Figure 17, is a transverse section upon plane of line 5, 5, Figures 17 and 18;
Figure 18, a side view of the valve chest ;
Figure 19, a vertical section of the valve chest upon plane of line 2, 2, Figure 18,
showing the governor air relief valve and conduit;
Figure 20, is a horizontal section of the valve chest upon plane of line 3, 3,
Figures 17 and 18;
Figure 21, is an elevation of the inner face of the valve chest, removed from
the power cylinder ;
Figure 22, is a top view of the bushing used in holding the gas valve seat in
position;
Figure 23, a transverse section upon plane of line 4, 4, Figure 17, showing the
ports through which the ignitor is heated before starting the engine;
Figure 24, is an end view of the ignitor casing ;
Figure 25, is a vertical sectional view through a portion of the power cylinder
and the carburetter and its eduction pipe;
Figure 26, is a horizontal section of a portion of the carburetter and the.
hydro-carbon feeder ;
Figure 27, is a sectional elevation of the governor.
The cylinder A, the water jacket B, and framework C, are preferably all
cast in one piece, a recess D, being formed in the frame below the cylinder
and water jacket and above the cam shaft E, for the reception of the carburetter D¹,
when used in lieu of any other source of gas supply.
The cam shaft E, and the power or crank shaft F, are situated transversely
to the power cylinder A, their axes being in the same vertical plane, midway
between the ends of the said cylinder.
The trunk pistons G, G' are connected by their rods g, gl, to the upper ends
of the rock levers H, H, mounted upon rock shafts h, ', the opposite ends of
the said rock levers H, H', being connected by the pitmans I, I', to the cranks f, f³‚·
respectively.
By reference to Figures 6 and 8, it will be seen that the cranks f, f', are
double cranks, the wrist pins f, f, f, each being supported by two webs f³.
The wrist pin, is arranged centrally between the two inner webs f,and is clasped
by the stirrup i, of the straight pitman I, pivotally connected to the lower end of
the left hand rocking lever H. The other pitman I', in like manner pivotally
connected to the right hand rocking lever H', is bifurcated at its inner extremity,
being formed with the stirrup arms I, 1, which extend back a sufficient distance
to enable the pitman 11, to straddle the middle crank f,-the space between
the arms I, I, and the web, being sufficient to admit of the passage of the said
crank, when both the pitmans I, I', have reached the full extent of their inward
stroke caused by the outward stroke or separation of the trunk pistons G, G'. The
stirrups, i, at the ends of the arms 1', 1', clasp the wrists ƒ³, ƒª, respectively, so that
the outer cranks f', f', act virtually as one crank, opposed to the central crank f. It
is to be noted however that the axes of the wrists, are all in the same plane
and that they are equi-distant from the axis of the two sections of the crank or
power shaft F, so that they naturally balance each other in all positions. To
compensate for the difference in weight between the two pitmans I, 1', the webs f',
are widened or thickened, or otherwise increased in weight at their extensions f
(see Figure 9) beyond the crank shaft F, upon the side upon which the wrist f, is
situated thereby counterweighting the arms 12, I, and the duplex cranks f, f.
The crank shaft F, is secured in the lateral bearings c, c, formed in the frame C,
by caps c', c. At its front end it is provided with a pinion F', while its rear end
carries the balance wheel F.

page_text: The pinion F1, meshes with the spur gear E', upon the front end of the cam
shaft E. The gear E', is twice the diameter of the pinion F', and consequently
two revolutions of the power or crank shaft F, are necessary to effect one revolu
tion of the cam shaft. The latter rotates in, bearings c³, c³, formed in the frame C,
being held against longitudinal movement by the shoulder, of the pumping cam J,
in front, and by the shoulder k, of the exhaust cam K, at the rear, or by other
suitable means.
The cam shaft E, is made hollow to receive the governor rod L, which is free to
slide therein longitudinally under the action of the governor L', attached to the
spur wheel E'.
Arms or brackets e, e, project outward from the face of the spur
wheel E, to which are pivotally connected the bell crank levers l, l. The outer or
shorter arms l', ', of these crank levers engage with the head or socket piece,
which is secured rigidly to the governor rod L. The longer inner arms 1, 1, of
the crank levers. l, l, project backward through slots e', e, in the gear E', and carry
the centrifugal weights 1, 1, which are connected by the springs 1, 1, which
tend constantly to draw the said weights inward toward each other and hold them
in their normal position in which position the head, and rod L, are drawn forward.
The relief valve cam M, is situated loosely upon the rear end of the shaft E, being
secured rigidly to the cam rod I, by a stud or cross bar m, passing through the
longitudinal slots e², e³, formed in the shaft E. The relief cam M, consists of a
concentric hub or sleeve m², formed with an eccentric portion or cam surface m².
When the governor L', is at rest and the parts in their normal positions
as shown in the drawings, the governor rod L, holds the concentric portion m',
of the relief cam M, under the valve rod n, of the relief valve N. When the
speed of the engine causes the weights, 13, to separate against the tension of
the springs,, thereby acting through the crank levers 1, 1, and heads P, to
move the governor rod L, inward, the eccentric portion m³, of the cam M, is brought
under the valve rod n, of the relief valve N, so that the valve will be raised from
its seat at every revolution of the cam shaft until the eccentric portion_m², of
the cam is withdrawn, and the concentric portion m', again comes under the
valve rod.
The carburetter D¹, consists of an oblong box or compartment resting upon a
shelf or table c³, formed in the frame C, for its support beneath the cylinder A,
and water jacket B. A suitable amount of absorbent material is arranged within
the compartment D', in such manner as to present the hydro-carbon for admixture
with the air passed through it. As shown in the drawings this absorbent
material consists of two or more sheets or layers of felt or similar material d, held
apart by blocks d, of the same material and formed with perforations &, for the
passage of air and vapor.
The hydro-carbon is supplied to the carburetter D', through an automatic
feeder O, interposed between the supply pipe o, which proceeds from the reservoir
or other source of supply, and the inlet pipe o', (see Figure 26). The feeder O,
consists of a vessel formed with a valve chamber o³, into which the supply pipe
enters. The valve o, is connected to a float o, arranged to close the valve o³,
when the liquid hydro-carbon attains a certain height in the feeder O. This height
corresponds to the level at which it is designed to maintain the hydro-carbon liquid
in the carburetter.
Air is admitted to the carburetter D', through the pipe P, provided with the
damper or regulator p. By reference to Figure 7, it will be seen that the pipe P,
is closed above the damper p, although it acts as a support for the upper portion
of the vapor conduit Q. It will also be seen that it is extended down into the
carburetter below the absorbent material so as to insure the passage of the air
through and around the latter. The vapor conduit Q, through which the air
charged with the hydro-carbon vapor leaves the carburetter is connected with the
transverse conduit Q', which extends over the working cylinder and opens into the
valve chest R, upon the opposite side of the cylinder. A combined throttling
and mixing valve is interposed in the transverse conduit Q'. This consists of a.

page_text: 9,
valve, disc
which is rotatable upon a diaphragm q', extending across the section
of the conduit Q1, the diaphragm and the rotatable valve disc being formed with
ports which may be brought into coincidence or closed by means of the handle g³.
The conduit Q', is divided by a partition 93, in front of the valve seat or
diaphragm g', (see Figures 6 and 13) forming an air passage 7, into which air is
admitted through the opening g', controlled by the sleeve damper q. The lower
quadrantal port 97, in the diaphragm q', opens into this air passage q', while the
other upper quadrantal port q³, opens into the vapor or gas channel. The
throttling disc 9, is formed with a semi-circular port 9, so that by rotating
the disc q, more or less to the right or left the relative areas of the ports q', 9,
may be varied to regulate the degree to which the gas is diluted by fresh air prior
to its being drawn into the power cylinder A.
The conduit Q', enters the valve chest. R, above the inlet or feed valve r, which
opens inward into the valve chamber S, the latter coinciding with, and forming a
continuation of, the cylinder port a, situated midway of the length of the cylinder.
The feed valve r, tends constantly to close against its seat r¹, by reason of the
spring, bearing against the collar, upon the valve stem, which latter
extends upward through the bushing, and cap, to and through a perforation t, in
the lever T, and is provided with jam nuts 7, 8, which perform the function of
an adjustable shoulder above the said lever T.
In the same axial line with the feed valve r, is the exhaust valve k¹, opening
upward into the valve chamber S, against the resistance of the spiral spring k³,
which tends constantly to hold it down against its seat k³, by reason of its bearing
against the lower end of the sleeve k, and its engagement with the eye k³, at the
lower end of the valve stem k". The exit valve k', controls the entrance to the
exhaust passage A', which opens into the exhaust pipe k³.
The relief valve N, is in like manner held normally against its seat n', by a
spiral spring n², attached to the lower end of its stem n, and bearing against the
lower end of the sleeve n³. Its stem n, extends upward through the valve
chamber S, and cap s, to the lever T, the outer end of which rests upon it. The
relief valve controls the entrance to the air conduit ', the other extremity of
which opens into the atmosphere. Flat springs ko, and no, are interposed between
the lower ends of the valve stems k, and n, and the cam K, and M, to protect
the surfaces of the latter against undue wear.
The ignition chamber U, opens into the valve chamber at right angles and in
line with the feed and exhaust valves r, and k'. The ignitor V, is preferably of
the form described in my United States Letters Patent No. 518,717, dated
April 24th, 1894, although any other form of ignitor may be substituted. As
shown in the accompanying drawings V, represents the platinum igniting cap
padded with loose or spongy material as set forth in said Letters Patent.
The igniting cap is fed with hydro-carbon vapor under pressure through pipe o,
which extends to the carburetting chamber v¹, through the pipe ». This pipe o³,
is connected by pipe 3, with an accumulator 1, consisting of an accordion bellows
provided with a weight v, or other well known means for effecting a similar result.
The air is supplied to the ignitor V, during the operation of the engine by an air
pump W, connected by pipe w, with the pipe, running to the carburetting
chamber v', the accumulator v', tending to equalize the pressure. The pump W
is preferably operated by a cam J, upon the cam shaft E, said cam actuating a
spring lever ', against the resistance of a coiled spring w².
When the engine
stops temporarily it is desirable to maintain the supply of hydro-carbon to the
ignitor under pressure in order to maintain the platinum in an incandescent state,
and this the accumulator will do for several minutes; but should a longer delay
occur the auxiliary hand pump X, provided for such an emergency, is utilized in
supplying the accumulator o, with air. A check valve x', is interposed in the
pipe x, between the hand pump X, and the accumulator v', so as to cut off the hand
pump from the accumulator when the engine is in operation and the pump W,
performing its function.

page_text: A water jacket B', surrounds the exhaust pipe 8, and communicates with the
water jacket B, surrounding the power cylinder A, through the medium of the
valve chest R. By reference to Figure 18, it will be seen that the exhaust
passage k, is partially surrounded by a water space b, which coincides with the
interior of the water jacket B'. This water space b, extends around the valve
chamber S, as will be understood by reference to Figures 17 to 21 inclusive, in
which latter figures are shown the water spaces which coincide and form continua-
tions of the openings 61, 61, into the water jacket B, as shown in Figure 6. One
branch B', of the water supply pipe enters the lower end of the exhaust pipe
jacket B while the other B, connects with the water jacket B at two points
below the power cylinder A. The exit B, lead from the water jacket B, above
the power cylinder; so that it will be seen that a complete circulation is insured,-
the water supplied to the exhaust pipe jacket B¹, having to pass through the valve
chest R, to the water jacket B, surrounding the power cylinder and the water
supplied to the said jacket B, having to pass around the cylinder A, before it can
make its exit.
The operation of the engine is as follows. Presuming that a charge of mingled
gas and air has just been fired, the pistons G, G¹ recede from each other imparting
the energy to the power shaft F, and fly wheel F2, through the medium of the
rods g, g', rockers H, H', pitmans I, I', and cranks f, f. As the pistons G, G',
start back toward each other the cam K, raises the exhaust valve k¹ from its
seat and by the time the pistons have reached the limit of their inward stroke
most of the products of combustion have been expelled and the cam K, allows
the exhaust valve k', to close. As the pistons again recede 'they create a partial
vacuum between them drawing in a fresh charge of mingled vapor through the
valve r, against the resistance of the springs. The pistons having reached
the outward limit of their stroke, and having thereby drawn in a considerable
body of gas and air, now compress the charge to about one third of its volume
during their approach, thereby forcing a portion of the charge back through the
valve chamber S, into contact with the incandescent torch V, and igniting the
charge, when the same cycle is repeated. It will thus be noted that up to a
prescribed rate of speed a charge is fired at every second revolution of the power
shaft, the cam shaft, as before set forth making only one revolution to two of the
power shaft. Should however the speed of the engine increase beyond a prescribed
degree the governor L', will throw the cam M, into action, so that the relief
valve N, will be opened and at the same time the supply valve r, will be positively
held closed by reason of the raising of the outer end of the lever T, (pivoted to t¹)
by the valve stem n, of the relief valve N. The result of this is that air alone is
admitted to the cylinder until the speed of the engine lessens sufficiently to allow
the governor to retract the cam M, when the relief valve N, closes automatically,
releasing the lever T, and permitting the supply valve again to yield against the
resistance of its spring, under a partial vacuum in the cylinder A.
In order to guard against possible back pressure or flame through a failure of
the supply valve r, to close for any reason, I provide the supply conduit Q', with a
safety valve Y, adjusted to open under an excess of internal pressure; and also
with gauze screens y, y, interposed in the passage.
I am aware that in United States Letters Patent No. 393,037, of Nov. 20th, 1888,
a duplex steam cylinder with closed ends, having both central and end ports, and
opposed steam pistons having rigidly connected piston rods, is shown, as connected
by links, rock shafts and pitmans to opposed cranks, upon a common power shaft,
but that arrangement could not be used as a gas engine, neither is it the equivalent
of my improved gas motor in which the single central port acts for both the charge
and discharge of the gas and the products of combustion, the open ends of the cylinder
allowing the pressure of the atmosphere to effect the return stroke, and the
connection between the trunk-pistons and the ends of the rock levers being effected
without links by rigid rods pivotally secured to the trunk pistons.
I do not seek to cover broadly a motor having its operative parts arranged

page_text: substantially in the same plane of action; I do claim however that I am the
first to produce a perfectly balanced gas engine in which noise and vibration are
reduced to the minimum, and this I effect by the special construction and arrange-
ment of parts herein shown and 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
claim is;
First. In a gas engine, the combination of an open-ended power cylinder formed
with a single central inlet and discharge port; two trunk pistons in said cylinder;
two rigid piston rods respectively pivotally connected at their inner ends to said
trunk pistons, and at their outer ends to rocking levers; said rocking levers.
consisting of arms projecting radially upon opposite sides of the fixed shafts or
fulcrums on which they are mounted; two pitmans pivotally connected at their
outer ends to the other ends of said rocking levers and at their inner ends to
radially opposed cranks upon a common power shaft; and said power shaft formed
with said radially opposed cranks having their common central plane of action
coincident with that of the common central longitudinal plane of the cylinder
trunk pistons, piston rods, rocking levers, and pitmans, for the purpose and
substantially in the manner set forth.
Second. In a gas engine the combination of a power cylinder formed with a gas
port, two pistons contained therein, two piston rods connecting said pistons with
two rocking levers said rocking levers supported upon fixed rock shafts or fulcrums,
a pitman connecting one rocking lever to a central double crank upon the power
shaft, a bifurcated pitman connecting the other rocking lever to two double cranks
on the power shaft, and said power shaft formed with three double cranks, the
central one opposed to the other two for the purpose described.
Third. In a gas engine the combination of a power cylinder formed with a gas
port, two pistons contained therein, two piston rods connecting the said pistons
with two rocking levers, said rocking levers supported upon fixed rock shafts or
fulcrums, a pitman connecting one rocking lever to a central double crank upon
the power shaft, a bifurcated pitman connecting the other rocking lever to two
double cranks on the power shaft, and said power shaft formed with three double
cranks the central one opposed to the other two, and the webs of the cranks upon
that side of the shaft being enlarged to counterbalance the weight of the two
cranks and the bifurcated pitman upon the other side of the power shaft,
substantially as described.
Fourth. In a gas engine the combination of a power cylinder formed with a gas
port, two pistons contained therein, two piston rods connecting the said pistons
with two rocking levers, said rocking levers supported upon fixed rock shafts, or
fulcrums, two pitmans connecting said rocking levers with separate cranks upon a
common power shaft, said power shaft formed with two opposed cranks, a hollow
cam shaft geared to the said power shaft, a centrifugal governor supported upon
the cam shaft, a sliding governor-rod resting in said hollow cam shaft and carrying
a cam arranged to lift a relief valve from its seat when the speed of the engine
exceeds a prescribed degree, and said relief valve interposed between the valve
chamber of the engine and the exterior atmosphere, for the purpose described.
•
Fifth. In a gas engine the combination of a power cylinder formed with a gas
port, two pistons contained therein, two piston rods connecting the said pistons with
two rocking levers, said rocking levers supported upon fixed rock shafts or
fulcrums, two pitmans connecting said rocking levers with separate cranks upon a
common power shaft, said power shaft formed with two opposed cranks, a hollow
-crank shaft geared to the said power shaft, a centrifugal governor supported
upon the said hollow cam shaft, a sliding governor rod resting in said hollow cam
shaft, a cam secured to said governor rod and arranged to lift a relief valve from
its seat when the speed of the engine exceeds a prescribed degree, said relief valve
interposed between the valve chamber of the engine and the exterior atmosphere,

page_text: mechanism actuated by said relief valve when raised to hold the supply valve.
positively closed, and said supply valve interposed between the supply conduit and
the valve chamber of the engine.
Sixth. In a gas engine the combination of a power cylinder formed with a gas.
port, two pistons contained therein, two piston rods connecting the said pistons with
two rocking levers, said rocking levers supported upon fixed rock shafts or
fulcrums, two pitmans connecting said rocking levers with separate cranks upon a.
common power shaft, said power shaft formed with two opposed cranks, a hollo
crank shaft geared to the said power shaft, a centrifugal governor supported upon.
the said hollow cam shaft, a sliding governor rod resting in said hollow cam shaft,.
a cam secured to said governor rod and arranged to lift a relief valve from its sent.
when the speed of the engine exceeds a prescribed degree, said relief valve.
interposed between the valve chamber of the engine and the exterior atmosphere
and formed with an extension of the valve stem which engages with the outer end
of a pivoted lever, said pivoted lever engaging with the valve stem of the supply
valve, and said supply valve interposed between the supply conduit and the valve
chamber of the engine, the parts being so arranged that when the relief valve is.
raised the supply valve will be held closed by the pivoted lever substantially as.
described.
Seventh. The combination with a gas engine, and with an incandescent ignitor
substantially as described, of an air pump operated from the cam shaft of the
engine, an accumulator for storing the air and equalizing its pressure, and a.
carburetter for charging the air with hydro carbon vapor prior to its introduction
into the ignitor, substantially in the manner and for the purpose described.
Eighth. The combination with a gas engine, and with an incandescent ignitor
substantially such as described, of an air pump operated by the cam shaft of the
engine, an accumulator for storing the air and equalizing its pressure, a carburetter
for charging the air with hydro-carbon vapor prior to its introduction into the
ignitor, and an auxiliary hand air pump for supplying the accumulator temporarily
with air when the engine is stopped, substantially as herein set forth.
MARKS & CLERK,
18, Southampton Buildings, London, W.C., and
13, Temple Street, Birmingham.