Improvements in Gas Engines.
Year: 1890

page_text: Date of Application, 14th Oct., 1890-Accepted, 15th Nov., 1890
COMPLETE SPECIFICATION.
[Communicated from abroad by CHARLES WHITE, Manufacturer, and ARTHUR
RAPHAEL MIDDLETON, Manufacturer, both residing at Baltimore, in the State of
Maryland, one of the United States of America.]
Improvements in Gas Engines.
I, GEORGE MACAULAY CRUIKSHANK C.E. of 62 Saint Vincent Street in the City of
Glasgow, Registered Patent Agent and Fellow of the Institute of Patent Agents Jo
hereby declare the nature of this invention and in what manner the same is to be
performed as communicated to me to be particularly described and ascertained in and
by the following statement :-
In devising a gas engine designed to be run at a high rate of speed, and in which
an explosion takes place after every other reciprocation of the piston, or less frequently,
I have aimed to bring the number of parts down to the minimum, and to materially
lessen those parts which add to the cost of manufacture, thus simplifying the
construction, not only as to the number, but the character of its parts, and
thereby lessening its cost to a material degree. Further I bave kept in mind
the item of fuel, and have endeavoured to diminish in my improved construction
the cost of running the engine and to secure a maximum amount of power
with a minimum consumption of the propelling mixture. Further I have considered
the value of space and the lack of it in many situations where a source of power is
needed, and I have accordingly produced a structure of an exceedingly compact form
without in any way depreciating its power or durability. Further upon account of
the expense attendant upon the employment of skilled labor I have taken great pains
to arrange the parts of my engine in such a manner that no sensitive or weak parts
are exposed to the concussive action of the explosive, and no important valves to the
clogging and consequent injurious action of the residuam left by the explosions, and
hence an unskilled person can with perfect safety be given the care of the engine as
it requires no attention save the turning on or off of the cocks controlling the passage
of the cooling medium to the jacket of the cylinder; the fuel supply and the heating
medium to the igniting tube; the machine being automatic in all other respects, and
capable as hereinafter explained of governing its communicated power to the
requirements of the work. The means whereby these various objects are accomplished
I will particularly describe the preferred form and the best known to me being
represented in the accompanying drawings, in which :
Fig. 1 is a sectional view of the cylinder and piston of the engine while the crank
shaft with the governor are shown in plan.
Fig. 2 illustrates the engine in side elevation, the cylinder, piston and igniting
devices being in section.
Fig. 3 is an enlarged sectional view of the igniting devices.
Fig. 4 is a detailed sectional view of the piston, enlarged, showing the valve therein
closed.
Fig. 5 is a front clevation of the cylinder and piston showing particularly the
connection between the star wheel carried on the piston rod and the pawl carried by
the piston.
Fig. 6 is a detailed view of the governor mechanism this being shown partly in plan
and partly in section.
Fig. 7 is a side elevation of the governor devices.
Fig. 8 is en end elevation of the same, partly in section, and
Fig. 9 is a detailed view of the slide operated by the governor io interrupt the
regular explosion.
My engine comprises a jacketed cylinder, as at A, of a size as to length and diameter
as may be required by the work for which it is intended; a cooling medium such as
air or water being introduced within the space between the walls. The piston B

page_text: moves within the cylinder being fitted thereto, and properly packed in any well-known
manner to make a gas-tight connection with the cylinder walls. A piston rod extends
between the piston and the crank shaft. D of the engine. The piston is propelled by
the explosion of a mixture of gas and air admitted to a chamber in rear of the piston
the arrangement being such as to allow of an explosion after every other reciprocation
of the piston or of less frequency if the work does not require alternate explosions,
the frequency of the explosions being automatically controlled so as to prevent any
undue waste or unnecessary speed under the changing conditions of the work.
The explosion chamber is in rear of the piston, as at E and this space also serves as
a compression chamber for the mixture preparatory to its ignition. The piston is of
tubular form with its rear end closed except where a port a is made leading from the
explosion chamber to the channel & which channel passes through the piston for about
half its length, opening through an elongated port to the exhaust pipe c.
The port
in the end of the piston is provided with a valve d which as hereinafter described
closes the passage to the exhaust under certain conditions, and is operated to open it
under other conditions. The valve d is carried upon a stem e which is guided in its
movements by the walls of the openings through which it passes in the front and rear
walls of the passage or channel and the front end of this stem carries a spring held
between the nut on the threaded end of the stem and the wall. The tension of the
spring may be regulated as required.
After an explosion has taken place the piston is driven to the front until its rear
edge reaches the exhaust port when the exploded mixture flashes out, and the force of
the charge is then spent. In this forward movement the valve d is tightly closed
upon its seat which is made dish shaped so as to bring the outer face of the valve flush
with the rear face of the piston, but as the backward movement of the piston takes
place the valve is moved forcibly from its seat as hereinafter described and an exit is
thus opened through the channel to the exhaust for the escape of the foul mixture.
This frees the space in rear of the piston from the exploded compound and thus the
next charge admitted is practically entirely fresh, and a minimum amount of the old
mixture remains, thus enabling me to gain largely in power by the explosion of a fresh
charge over a charge largely composed of spent mixture ordinarily remaining in the
explosion chamber. In such cases where the chamber is heavily charged with the
exploded mixture not only does it prevent the admission of a proper amount of
the fresh mixture, but by the detrimental adulteration materially diminishes the
estimated force ordinarily derived from the explosion of a determined charge. I
entirely avoid this serious objection by expelling the exploded mixture down to one
atmosphere in the return stroke of the piston succeeding an explosion. The gas or
vapour is admitted to the explosion chamber through the ports covered by the valve i
shown in Figure 1, this valve being normally closed by a spring, but opened to admit
a charge by the suction of the piston as it moves forward after the chamber has been
emptied of the exploded mixture. The gas or vapour is admitted to the space in rear
of the explosion chamber through the pipe which may be in connection with any
suitable source of supply, but the flow of gas is interrupted by a valve k as in Figure 1,
this valve being automatically controlled by a governor mechanism hereinafter to be
described which by thus allowing or preventing the flow of gas to the chamber controls
the number of explosions, the governor operating to admit the gas according to the
requirements of the work.
The igniting devices are arranged at the end of the piston as shown particularly in
Figures 2 and 3. The chimney is mounted on the cylinder and is in connection
with a gas pipe m or other source of heat, and in the centre of the chimney
is the igniting tube n the interior of which is a continuation of the opening
passing through the cylinder to the interior thereof. The tube n, becomes heated
under the action of the flame and the charge is ignited through the opening o.
The opening o is normally closed by a valve consisting of a spring ring mounted on
a sliding tube y, fitting a socket or recess extending longitudinally of the cylinder and
intersecting the passage o. The spring ring by its elasticity forms a perfect valve and
prevents absolutely all danger of leakage, and consequently premature explosions.

page_text: q
The tube is carried by a block which is kept normally forward by a coiled
springs and this block has a stem projecting through the head of the cylinder as
shown in Figures 2 and 3 where it is in tho path of a like stem secured to the rear
face of the piston as at u. In order to lubricate the sliding tube 9 and the other parts
within the recess or space in the cylinder head, I provide an oil cup e provided with a
valve we which is kept closed by the back pressure, but when the piston moves forward
the pressure is relieved, the valve drops, and the oil is drawn out and diffused. A
tube e conducts the oil to the sliding tube y extending partly into the same and this
tube q is provided with an opening or openings at its forward end through which the oil
passes to the bearing surface. A valvey opening into the explosion chamber opens as
the piston moves forward, but on the back movement closes and prevents the blowing
out of the oil in the cup. This valve works in a passage which is shown in dotted lines
in Figure 3; extends to the rear and thence upwardly so that its upper open end is
above the line of the oil delivery tube and tube 7, thus preventing the oil from being
sucked out in the forward movement of the piston. The suction of the piston is utilized
without danger of emptying the recess occupied by the igniter and its operating parts
from the oil contained therein thus those parts are always thoroughly lubricated.
I have referred to the alternate opening and closing of the valve in the piston so as
to permit the discharge of the exploded mixture in the rear movement of the piston
and to prevent the escape of the fresh charge or the force of the explosion in the
forward movement by the closing of the valve, and I will now describe a preferred
means of effecting the result automatically by the oscillation of the piston rod, though
I do not limit myself in this respect, as the means shown may be greatly modified
and changed without departing from the spirit of this part of the invention. The
piston red is provided with a screw threaded socket in its end adapted to receive the
threaded shank of the eye which is pivoted to a bar or rod a crossing between
the walls of the piston. Between the shoulders of the eye and the end of the piston
rod is supported a star wheel c' having an elongated hub, which in turn supports a
ratchet wheel d. The star wheel is freely mounted on the shank of the eye b¹ but
frictional contact is secured sufficient to prevent accidental slipping, by the plugs e',
pressed outward by springs bearing against the end face of the piston rod proper. A
supporting projection, from the interior periphery of the piston carries a spring
pawl adapted to engage with the teeth of the ratchet din the up and down
movement of the piston rod, this movement bringing the teeth of the ratchet into
engagement with the pawl which causes the ratchet to revolve, carrying with is the
star wheel. This wheel E has a series of projections alternating with spaces and the
wheel and stem of the valve d are so arranged relatively to each other that the stem is
in the path of the wheel and when a space is opposite the stem the spring thereof
keeps the valve closed, but when a projection, as in Figures 1 and 2 comes in line
it engages the end of the stem as the piston moves down and forces open the valve.
I will now particularly describe the governor which has been heretofore referred
to. This is designed to automatically control the explosions as required by the work
by operating the valve in the pipe supplying the gas or explosive mixture. A rod i
extends between the engine and the governor devices, the rear end finding bearings
in openings passing through a part of the cylinder. A spring bearing against a
stop keeps the rod pressed constantly toward the front, and the arm thereon
away from the stem of the valve in the gas supply pipe, this valve being normally
closed by a spring m. The front end of the rod is connected to a slide n' which
moves in ways formed for it in a bracket o' extending from the bearing pl. Between
the slide and the operating cam on the crank shaft is a second slide q' with a
spring interposed between the two slides to take up the shock and allow the action
of the one upon the other to be gradual. The slide q' carries upon its forward end
a pin s carrying a disc t' freely mounted thereon and pressed outward by a spring,
and this disc is adapted to engage and ride over il cam shown fully in
Figures 6 and 7 arranged closely against the angular part of the crank shaft. The
action of the cam is to advance the slide q' and through the second slide operate the
rod and thus open the valve in the gas pipe to admit a charge to the explosion

page_text: chamber through the arm coming in contact with the stem of said valve. The
cam is made with a slight rise which gradually increases as shown in Figure 7 to
avoid any great shock and consequent wear and while the disc is being operated by
this part of the cam but little power is required as the slide is simply being moved
towards the slide n' and by the time power is required to move the slide n¹ and its rod
the high part of the cam has reached the position of the disc. The cam is so
arranged as to provide for an explosion after every alternate reciprocation of the
piston, but as it often occurs that the work does not require explosions as frequent
I have provided an automatic regulator to govern the frequency of the explosions by
controlling the movement of the rod actuating the valve in the gas pipe. To the
angular part of the crank shaft, as at 1 secure a bracket having a bifurcated pro-
jecting portion w¹ supporting a pin which serves as a pivot for a bell crank lever l
baving one end weighted. In addition to the weight to still further add to the tension
of the bell crank a stem y' is secured to the angular part of the bell crank passing
through the weight with a nut on its projecting end and a spring interposed between
the nut and the wall of the cavity in the weight occupied by the spring. The opposite
end of the bell crank is reduced as shown in Figure 9 and this fits an inclined slot
in a shifting block which has lateral movement in a passage formed through the base
of the bracket e. This block has its end made inclined, and as soon as the speed of
the engine begins to increase beyond the requirements of the work, the centrifugal
action on the weighted end of the bell crank moves the inner end and operates through
the inclined slot to shift the block laterally which thus brings its inclined end into
the path of the shifting disc thus forcing it to one side and out of the path of the cam
thus causing the engine to miss its regular explosion, and this is done as often as the
governor is operated under the varying condition of the work. As the intermittent
movement of the star wheel is uniform presenting a space and then a projection in the
path of the stem of the valve d it will be seen that the rod for operating the valve in
the gas pipe must be moved by the governor with regard to the movement of the star
wheel, or else in the missing of an explosion the order of movement would be changed,
and a charge admitted on the wrong stroke of the piston. In order to cause the
movement of the rod only at the proper time in relation to the position of the star
wheel I provide the slide n' with a disc 4 having recesses or pockets in its periphery,
this wheel being secured to one end of a short spindle 1 which has its bearings in the
face plate covering the slide n'. A ratchet wheel 2 is carried on the other end of
the spindle, and the teeth of this wheel are engaged by a long pawl 5 carried on the
slide . The slide 4 also carries a pin 3 having a conical end, which is guided in its
movement through an opening in the slide . The recesses or pockets in the dise
are of different depth, a shallow one alternating with a deeper one. In the ordinary
action of the mechanism operating the rod controlling the valve in the gas pipe the
slide q' is advanced by the cam on the crank shaft as before described until the pin 3
engages with one of the recesses in the disc 4 and if this is one of the shallow
recesses the amount of movemont is sufficient to move the slide n' and its rod, and
thus open the valve to admit a charge. In the same movement of the slide g¹ its pawl
turns the ratchet wheel which brings a deep recess or pocket in line with the pin and
in the next movement of the slide the pin enters the deep recess, and as the depth
is sufficient to take up all the movement of the pin, the slide n' is not operated and
no charge admitted to the engine, but the pawl operates the ratchet to bring the next
recess, a shallow one, around for the next action of the pin, thus providing for an
explosion under normal conditions on every other movement of the slide q' thus
timing the explosions to accord with the movement of the piston; and the position
of its valve is controlled by the star wheel, the relation being such that when a pro-
jection of the star wheel is in contact with the stem of the piston valve a deep notch
is in line with the pin 3 and when a space of the star wheel is opposite the valve stem,
a shallow recess is opposite the pin and the valve in the gas pipe operated. I pro-
vide however for the less frequent operation of the valve in the gas pipe than in the
alternate order stated without interrupting the relative movements of the star wheel
and slide by arranging alongside the cam a' a second cam ² and thus when the

page_text: disc is shifted by the block out of the path of the cam uit engages the cam u
which is of less height than its companion cam, and the movement imparted to the
slide is of such limited extent as to render ineffectual the action of the slide y' on the
slide though a shallow recess be opposite the pin 3. The action however is
sufficient to move the ratchet wheel to turn the recessed disc and thus the relative
positions of the star wheel and disc are maintained.
A pin limits the upward movement of the pawl of the slide 7. While I have
described the mixture used as being gas and air it will be understood that any
suitable fuel may be substituted therefor.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to me
1 declare that what I claim is :-
1. In a gas engine a cylinder having a main exhaust, a piston therein, a supplemental
valved exhaust passage from the explosion chamber and means for opening the
supplemental valve on every alternate reciprocation only of the piston to discharge
the exploded contents under the action of the piston substantially as described.
2. In a gas engine a cylinder a piston having a passage through the same leading
to the exhaust, a valve controlling said passage and automatic means for opening
said valve on every alternate reciprocation of the piston substantially as described.
3. In a gas engine a cylinder a piston having a valved passage and a star wheel
operated by the movement of the piston rod to alternately present its projections and
spaces in the path of the valve stem, substantially as described.
4. In a gas engine a cylinder a piston having a valved opening leading to the
exhaust a piston rod, a star wheel, a ratchet wheel in connection therewith, and a
pawl, these parts being carried by the piston and rod, the pawl engaging the
ratchet to move the same under the oscillation of the piston rod, substantially as
described.
5. In combination with a gas engine, an igniting opening, a slide valve covering
the same;
said valve and the operating parts connected therewith being located in a
recess in the end of the cylinder head, an oil cup in connection with said recess
having a valve and a valve located in a recess in the inner face of the cylinder head,
substantially as described.
6. In a gas engine, a cylinder, a piston, a gas supply pipe, a valve therein and
controlling means therefor operated by a cam on the crank shaft a weighted governor
lever, a laterally movable dise adapted to be acted upon by the cam on the crank
shaft under ordinary conditions, and a laterally movable block operated by the governor
to deflect the laterally movable disc and thus miss an explosion, substantially as
described.
7. In a gas engine, a cylinder, a piston therein, a gas pipe and valve, a rod for
operating said valve, a two part slide with yielding means between a cam on the
crank shaft, and a shifting disc carried by one of the slides with means for shifting
the same, substantially as described.
8. In a gas engine, a cylinder, a piston, a gas pipe and a valve, a cam on the crank
shaft, an operating connection between said shaft and valve, a shifting disc forming
part of said connection, and means for shifting the same under the action of a governor
weight, substantially as described.
9. In combination with a valve in the explosion chamber of a gas engine, and with
means for opening said valve during every alternate reciprocation of the piston, a gas
pipe and valve and means for controlling the inlet of the gas consisting of an
operating rod, a slide connected thereto, a recessed disc carried by the slide and
having a ratchet wheel on one end the recesses being of different depth alternating
in position, a second slide with a spring interposed between the two, a pin for engaging
the recesses of the disc, a pawl carried by the second slide and engaging the ratchet
of the first and means for controlling the second slide substantially as described.
10. In a gas engine an igniting opening, a valve therefor carried by a sliding tube

page_text: an oil cup, a passage extending through the cylinder head, a valve y therein, said
passage opening into the recess in the cylinder head above the line of the sliding
tube, substantially as described.
Dated this Thirteenth day of October 1890
CRUIKSHANK & FAIRWEATHER,
62, Saint Vincent Street, Glasgow, Agents.