IMPROVEMENTS IN GAS MOTOR ENGINES to be as follows:
Year: 1885

page_text: We RICHARD M°GHEE Commercial Traveller of 182. Trongate Glasgow and
GEORGE MAGEE Engineer of 690 Springfield Road Glasgow Lanarkshire do hereby
declare the nature of our Invention for "IMPROVEMENTS IN GAS MOTOR ENGINES
to be as follows:-
"
Our invention consists of improvements in gas motor engines, and it comprises
means for obtaining from each charge of combustible mixture the highest available
expansion, for minimising the friction of the slide valve, and for governing the
movement of the valve and the supply of combustible.
We form in connection with the engine cylinder a receiver which may be pro-
vided with an elastic diaphragm or a loaded plunger and we so arrange the ports
in the cylinder and valve that during the outstroke of the piston a charge of gas
and air is drawn into the cylinder and during the instroke a portion of the charge
is pressed back into the receiver while the remaining portion is compressed at the
back end of the cylinder. On the return outstroke or after the crank has turned
the dead point this compressed charge is exploded by the opening of the ignition
port of the valve and propels forward the piston while on the return instroke
the exhaust port of the valve opens for the outward passage of the products of
combustion.
At the point when the piston commences its next outstroke to draw in a sub-
sequent charge the receiver opens to the cylinder and the charge within it is first
drawn into the cylinder followed by a further supply from the air and gas supply
tubes. The receiver is closed from the cylinder by the movement of the valve and
the communication between the cylinder and receiver being through a port in the
valve whose motion is suitably regulated the charge in the receiver can only be
withdrawn at each alternate outstroke. The object of employing a receiver to
contain a portion of the charge is that space may be afforded for the greater
expansion of the remainder and that there may be no vacuum in the cylinder
during the outstroke.
The receiver is provided with two valves serving to close off the gas and air
supply so long as there is a pressure within the receiver, but opening whenever the
receiver is emptied and the suction of the piston on its outstroke acts to lift them
from their seats on the gas and air supply passages. The same object may be
attained without the use of the receiver by arranging the slide valve to operate
earlier and cutting off the supply of combustible mixture at any point of the travel
of the piston.
The valve we employ for controlling the supply and ignition of the charge is a
slide valve which is inclined on the back, a separate valve being employed for the
exhaust. The valve works against a plane surface on the cylinder provided with
ports corresponding to those in the valve. On the back of the valve is an anti-
friction roller or rollers which keep the valve against its seat and which while
D

page_text: offering little resistance to the travel of the valve by bearing on the highest point
of the inclined surface at the moment of explosion press it tightly down and prevent
any back movement of the valve.
The slide valve is operated through a rod by a cam on a shaft geared to the
crank shaft and revolving at half the speed of that shaft. The shape of the cam is
such that at several points in the cycle of operations of the engine the valve
remains stationary and at other points it travels at a high speed the object being
to control the supply and ignition of the charge and to cut off the supply at any
desired point while giving it the least possible travel.
At the point when the piston drawing in a charge has completed its outstroke
two valves placed on the air and gas passages respectively close and cut off the
supply. The valves open again at the point when the piston has drawn the
combustible mixture out of the receiver.
On the ignition cavity and communicating with the cylinder we place a valve
through which the piston is supplied with air when the slide valve being at rest
the regular supply of mixture is cut off.
When the engine is working above the normal speed the slide valve is released
by the governor and it stops at the point when the ignition cavity is in communi-
cation with the cylinder the communication between the cylinder and the receiver
being at the same time cut off.
To control the movements of the slide valve and to regulate the supply of
mixture both for the charge and for the purpose of igniting we use a governor of
the ordinary type but with a weight so attached that when the engine is working
above the normal speed it will operate upon the centrifugal force of the balls and
when the engine is working below the normal speed it will operate against the
gravitation of the balls.
The valve rod is made in two parts and the governor is arranged to interpose or
withdraw from between the lengths of the valve rod a separate piece or a part of
the rod so that in the one case the rod acts as one piece and operates the valve in
the usual way while in the other case the end of the valve rod next the cam is
moved as usual but it does not communicate motion to the end which is attached
to the valve and the valve remains closed.
To produce an equilibrium between the compressed charge and the supply for
ignition at the time when the charge is being ignited we place a bridge across the
orifice of the ignition cavity leaving a passage at the back of the bridge to allow
the air to pass. The part of the cavity below the bridge forms the air passage
while the part above the bridge forms the ignition space which connects with the
usual funnel. On the bridge there is a small passage which opens to the cylinder
port a little ahead of the ignition cavity so as to admit a small portion of the com-
pressed charge to pass into the ignition cavity below the ignition flame.
A difficulty in the proper working of gas engine heretofore has been that
when the valve facings have been slightly worn the force of the explosion has
extinguished the ignition flame. This has been especially the case at the starting
of the engine. To overcome this difficulty we place on the slide valve a small
tongue which travels back and forth with the slide valve and which at the time of
explosion closes the cavity in which the external flame is burning.
To produce an equilibrium between the compressed charge in the cylinder and
the ignition when a groove in the cylinder face is not made we use instead of a
bridge across the ignition cavity a small projection stretching only partly across
the cavity. In this projection there is a small passage which communicates with
the ignition cavity and which as in the bridge opens to the cylinder port a little
ahead of the ignition.

page_text: We, RICHARD M°GHEE of Glasgow in County of Lanark North Brittain and
GEORGE MAGEE of Glasgow aforesaid, do hereby declare the nature of our
invention for IMPROVEMENTS IN GAS MOTOR ENGINES and in what manner the
same is to be performed, to be particularly described and ascertained in and by
the following statement, reference being had to the accompanying Drawing :—
..
The said invention consists of improvements in Gas Motor Engines and comprises
means for obtaining from each charge of combustible mixture the highest available
expansion for minimising the friction of the slide valve and for governing the
movement of the valve, and the supply of combustible mixture.
Fig. 1 shows a side elevation and Fig. 2 a plan of an Engine as constructed
according to this Invention.
Figure 3 is an enlarged vertical part section lengthwise of the slide valve on
valve face plate and Figs. 4 & 5 respectively a horizontal and transverse section
thereof. Fig. 6 represents section of Receiver and elevation of face plate.
The several parts of the Engine are shown as when the piston is at half stroke.
out drawing into the cylinder the combustible mixture of gas and air.
The Engine comprises the cylinder a which is provided with the ordinary water
jacket. On the side of the cylinder is bolted the valve face plate b against which
the slide valve is reciprocated by the rod c In connection with the cylinder may
be a receiver the object of which is to contain a portion of the charge of com-
bustible mixture (hereinafter simply termed mixture) The receiver is placed on
inlet mixture supply pipe and as shown at Fig. 6 consists of a case or chamber d
provided with an india-rubber or other flexible diaphragm or diaphragms e and
inlet tube or orifices for gas g and air f, fitted with a valve h which valve may
be kept when not otherwise acted on, against its seat by a light spring (not shown),
but which said valve is preferably placed so as to be vertical and thereby take its
seat by its own weight. The valve is guided by the ring i. In lieu of said single
valve h the air and gas supply orifices may be separate and each provided with a
valve. The cylinder is longer than the stroke of piston h¹ which only travels to
line g. The piston is connected as usual to the crankshaft k on which is fitted a
pinion so geared to a toothed disc or cam m as to revolve said disc at half speed.
of crank-shaft. The pitch lines of said disc and pinion are represented in Fig. 1
by dotted lines. On the face of the disc is a groove n into which a roller o at one
end of the rod p fits. The shape of the groove n is indicated more plainly at
Fig. 8 (which is a diagram of the disc) the dotted line n indicating the centre
line of groove the shape of which determines the motion of the rod p.
Referring to Fig. 8 the travel of the rod p will be between the point o and
circle q. Assuming the disc to be revolving as shown by arrow and the groove
divided into four parts as shown at points r. 8. t. u. each part will represent the
revolution of the disc during one stroke of the piston, the supply stroke of piston,
lying between points r. 8. and compression 8. t explosion t. u. and exhaust u. r..
respectively. When the modification of Engine with receiver is used, the supply

page_text: of mixture having commenced at beginning of stroke and corresponding to point r,
the groove n would require to keep out more than as indicated, so as not to shut
off till point 30 corresponding to about instroke was reached, so as to press back
some of the mixture into receiver again. When no receiver is used the shut off
of supply of mixture will be about point 31 so as to shut off about
outstroke.
By varying the shape of the groove the motion of the rod p may be varied
correspondingly.
For minimising the friction of the slide valve x it is kept pressed lightly for its
greatest travel against its seat as shown at Figs. 4 and 5 (Fig. 5 being a section
on line v) by the spring z which bears on the block y in which is fitted the anti-
friction roller 10. The pressure of spring z can be varied by screw 20 which is
fitted into cross bar 21 fixed to bolts 22 fitted into cylinder a The back of slide
valve between points 23 & 24 is inclined outwards so that when the ignition
cavity 1 is opposite cylinder inlet port 2 the roller 10 shall have been pressed
furthest outwards and have greatest pressure exerted thereon by spring z so as to
stand explosion.
Figure 7 represents a rubbing from the face of slide valve for facility of com-
parison with Figs. 3. & 4. The said valve x is connected to the rod c at hole 25
and has a mixture by pass cavity 3 & ignition cavity 1. To produce an equilibrium
between the compressed charge and supply for ignition when the charge is being
ignited a bridge 5 seen plainly in Fig. 9 (which is a transverse section of valve and
face on line 26) is made across the orifice of said cavity 1 leaving a passage at the
back of the bridge to allow the air to pass. The parts of cavity 1 below and
above the bridge 5 constitute respectively the ignition air supply passage, and
ignition space, and connects with the two ports 6 and 7 in the face plate b
Figs. 9 & Through the bridge 5 is a small passage 8 opening at one end to the
cylinder inlet port 2 a little ahead of the ignition cavity so as to admit a small
portion only at first of the compressed charge in cylinder, to pass through the
bridge into ignition cavity below ignition flame. The object of this is to produce
a gradual equilibrium between the compressed charge and igniting charge so as not
to extinguish the igniting charge by too sudden an exposure to compressed charge
of cylinder. Gas is supplied for the ignition charge by small port & pipe 9 in
plate band the external igniting flame by the pipe w; and in case when no
receiver is used, gas is supplied by flexible pipe 33 to gas supply port 35, the air
only being then inhaled by passage 29, both air and gas mixing together on way to
inlet port 2.
The exhaust port and valve 34 is opposite inlet port 2 and communi-
cates by a pipe 43 with the lower part of hollow pedestal 36 and then by pipe 37
with front hollow pedestal 38 from which the exhaust is led as most convenient.
The exhaust by thus passing through both hollow pedestals is considerably silenced.
The exhaust valve is opened by the lever 40 being actuated just at the beginning
of the return instroke of the piston after the ignition outstroke by the cam 39
which is fixed to and revolves with the spindle of disc m. The valve rod is made
in two parts p. c. one end of the rod p. being formed as shown in enlarged plan at
Fig. 10 with a wedged shape part a' and side parts 6' through outer end of which
slides rod c sufficient to enable the hinged tongue e¹ to clear wedge part a¹ some-
what as shown in Fig. 10. The wedge part a and tongue e as shown in Figs. 1
and 2 are met. The tongue is connected with a cord or chain guided by pulleys to
governor of Engine preferably placed on top of shaft as shown by x at Fig. 2 so
that when the Engine exceeds its normal speed the governor draws the cord and
raises the tongue e¹ clear of the wedge a' thereby leaving the rod c at rest, while
the rod p may be reciprocating the valve stopping when valve ignition and
cylinder inlet parts coincide. Fig. 11 illustrates the governor as applies for
regulating the supply of gas which flows through valve f¹ when opened by spindle
being pushed in against spring g' which tends to keep valve shut. On valve
spindle is jointed a rod h¹ with wedged shaped end against which when in its
normal position reciprocates the <shaped end of rod i¹ which is or may be attached
to the slide valve or other reciprocating part of Engine The rod h¹, is suspended

page_text: to the middle pulley k¹ by a cord or chain j¹, a weight resting on bracket m¹ being
attached by a cord or chain n¹ to the largest pulley. The smallest pulley o¹ being
attached by a cord or chain q¹ to the rising and falling stud 1 of a governor the
stud working in a slot in standard 8 the relative positions of the parts are shown
as intended to be when Engine is at its normal speed but should it exceed such,
the balls by centrifugal action would lift the stud r drawing with it cord
thereby turning the three stepped pulley which by cord 1 would lift the rod h¹
clear of the valve thereby remaining shut untill the speed lowered when the
rod would again push in the valve spindle thereby allowing the gas to flow
again. The weight offers resistance to the balls rising (immediately engine
exceeds normal speed) but by resting on bracket it does not tend to accelerate the
further fall of the balls, so as to lower the rod h¹ below rod which the balls tend
to do by their own weight when speed gets too low, thereby shutting of supply
altogether The weight may be dispensed with and in lieu thereof the weight u¹
on top of governor's spindle may be used to effect much the same purpose In this
case the balls would each be provided with an additional arm or lever indicated by
dotted lines x so as to bear against bottom of weight and support it.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that what
I claim is,
1st The arrangement and construction of Gas Engines as described and shown.
2nd In Gas Engines the combination with the cylinder, of a receiver constructed
and operating as set forth.
3rd In combination with a slide valve with inclined back the use of a roller as
& for the purposes described & shown.
4th Constructing a slide valve spindle for Gas Engines in two parts substantially
as & for the purposes set forth.
5th In combination with the lifting tongue on valve spindle, the use of chains or
cords and pulleys for Governing Engine.
6th The use of a cam in combination with a receiver substantially as & for the
purposes set forth in Gas Engines.
7th In combination with the Governors of Gas Engines the weights pulleys
& chains substantially as & for the purposes described & shown at Figure 11.
8th The particular construction & combination in the particular manner of the
slide valve & face plate as described & shown.
Dated this 2nd day of March 1886.