IMPROVE- MENTS IN GAS MOTOR ENGINES
Year: 1884

page_text: I, JAMES SHAW, of Lavender Walk, Leeds, in the County of York, Engineer and
Chemical Expert, do hereby declare the nature of said Invention for "IMPROVE-
MENTS IN GAS MOTOR ENGINES," to be as follows:-
=
In a gas motor engine according to my invention, the working cylinder, which is
closed at both ends and made in one or more parts, is so formed that there shall be
sufficient space behind the piston (when it is in its backward position,) in which
to explode a charge of combustible mixture of air and gas.
The cylinder is for about two thirds of its length (or its whole length may be)'
surrounded by a water jacket as is usual in such engines. I cause the combustible
charge to be automatically delivered immediately behind the piston when in its
rear or back position, the quantity of gas being regulated by any suitable governor.
To start the engine, the crank is placed somewhat forward of the dead point or
centre, then there is admitted by hand, a quantity of gas into the cylinder or com-
bustion chamber (close behind the piston) which gas mixes with the air therein.
Ignition is effected by means of an apparatus that I call a "Self-starter." It com-
prises a small chamber attached to a convenient part of the cylinder and provided
externally with two small apertures capable of being opened or closed, and one
internal aperture communicating with the combustion chamber, it also has a
partition between the two first named apertures which divides the chamber for
about half its length.
"
The two first named apertures being open, a jet of gas is caused to enter one of
them, the other acts as a vent through which air contained in the chamber is
expelled by the gas jet until a mixture of gas and air occupies such chamber, then
the gas jet outside is ignited and the flame being propelled into the chamber causes
an explosion therein, and thereby through the internal aperture the charge within
the cylinder is ignited and the piston caused to make its first outward stroke,
During this outward stroke the contents of the cylinder in advance of the piston
are expelled through two valves opening outward, one of them being placed at
about three fourths of the stroke and the other at the end thereof.-When the
piston has passed the first of these two valves and whilst the pressure of the
products of combustion (or that arising from the ignition of the combustible charge)
still acting on the piston, is in excess of that of the atmosphere, escape of such
products of combustion takes place through the said valve, until by such escape and
continued movement of the piston, the pressure in the cylinder falls below that of
2

page_text: the atmosphere, whereupon the valve is automatically closed and a partial vacuum
is created in the cylinder. The remainder of that portion of the contents of the
cylinder before the piston escapes through the valve situated at the end of the
cylinder. A new charge of air and gas is now admitted into the cylinder through
valves provided for the purpose and is delivered by pipes as close as possible to the
rear position of the piston as proviously mentioned. And in order that the creation
of a partial vacuum (above referred to) may be repented at the time the piston
completes each outward stroke, communication is opened between the combustion
chamber or rear part of the cylinder and a surface condenser, and immediately on
the commencement of the return or inward stroke of the piston (which is effected
by the momentum of the fly wheel,) a communication is also established between
such condenser and the front end of the cylinder, and by the action of the condenser
and the inward stroke of the piston, the combustion chamber is exhausted of all or
nearly all the products of combustion, such as steam and hot air generated by the
explosion of the charge.
These products are considerably roduced in bulk (partly to water) by the action
of the condenser, and in this state are drawn into the front end of the cylinder,
where a portion of them will lubricate the cylinder and piston, whilst the romaindor
will be expelled therefrom by the succeeding outward stroke of the piston. By
the time that the piston has travelled about two thirds of its inward stroke the
exhaustion of tho combustion chamber will have been completed and a new charge
will have occupied the same. In the condenser there will now be a partial vacuum
ready for the rapid exhaustion of the products of another explosion. During the
remaining one third of the inward stroke of the piston the said new charge becomes
slightly compressed so as to form a cushion, and whilst this compression is taking
place a portion of this charge will be forced into a tube, through a small aperture
in the end thereof. This tube is fixed in the side of the cylinder, the outer ond
being joined to a casing in which is a hollow valve of cylindrical or other external
shape having a reciprocating movement therein-This valve is provided with ports
or openings near its end, ono of which communicates with the abovenamed tube,
another opening being opposite to the first named one, and two others at right'
angles thereto. The hollow of this.valve is, by means of a pump charged with a
mixture of air and gas, which passes through perforations or their equivalent in the
sido of the valve into the interior; during the inward movement of the valve, a portion
of such mixture escapes through the first named openings and becomes ignited by a
. permanently lighted gas jet. While the beforementioned tube in the sido of the
cylinder is receiving its charge from tho cylinder, escape of the air previously con-
tained in the tube, is provided for by a passage in the hollow valve or otherwise.
During the backward stroke of the hollow valve communication of its contents
with the abovenamed lighted gas jet, is cut off, the flame becomes shut in the
hollow of the valve ignites the whole contents of such hollow part and explodes tho
charge in the tube, and through the small orifice in the end of the tube the com-
bustible charge in the cylinder is exploded and is thus caused to propel the piston
outward.
This explosion is arranged to take place when the crank is on the dead point
or centre, or thereabout.
By the time that the charge of air and gas is exploded and hot air and steam is
generated of sufficient pressure for propelling the piston on its outward stroke, the
momentum of the fly wheel has changed the position of the crank from the dead
point to a more forward and favourable one for impact upon the piston.
During this and subsequent outward strokes of the piston, water and other
residual products of combustion which are drawn into the cylinder through or from
the condenser, are expelled through the two previously named escape valves in the
cylinder.
While the piston is travelling the remaining one third of its inward stroke,
the exhaust valve or communication between the combustion chamber and the
condenser, is closed and the intensity of the partial vacuum in the condenser is

page_text: increased by the action of the abovementioned one third inward movement of the
piston; and on the piston commencing its next outward stroke, the communication
between the condenser and the front part of the cylinder is closed, thus leaving
the condenser in a proper state for exhausting the products of combustion
immediately the communication between the combustion chamber and the con-
denser is mechanically opened, such exhaustion being continued by every backward
stroke of the piston, removes all or nearly all the products of combustion from the
combustion chamber or cylinder and prepares the latter for the admission of a
complete charge of combustible mixture at each stroke.

page_text: I, JAMES SHAW, of Lavender Walk, Leeds, in the County of York, Engineer and
Chemical Expert, do hereby declare the nature of my said invention for "IMPROVE-
MENTS 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 :-
In a gas motor engine according to my invention, the working cylinder which is
closed at both ends and made in one or more parts, is so formed that there shall
be sufficient space behind the piston (when in its backward position) in which to
explode a charge of combustible mixture of air and gas.
The cylinder is for about two thirds of its length (or its whole length may be)
surrounded by a water jacket as is usual in such engines. I cause the combustible
charge to be automatically delivered immediately behind the piston when in its
rear or back position, the air by means of one or more pipes provided with a check
valve or valves, and the gas by means of a pump, the quantity being regulated by
any suitable governor.
To start the engine, the crank is placed somewhat forward of the dead point or
centre, tlien there is admitted by hand a quantity of gas into the cylinder or
combustion chamber (close behind the piston,) which gas mixes with the air
therein. Ignition is effected by means of a self-starter. This comprises a small
chamber attached to a convenient part of the cylinder and provided externally
with two small apertures capable of being opened or closed, and one internal
aperture cominunicating with that part of the cylinder forming the combustion
chamber, it also has a partition between the two first named apertures which
divides the chamber for about half its length. The two first named apertures
being open, a jet of gas is caused to enter one of them, the other acts as a vent
through which air contained in the chamber is expelled by the jet of gas until a
mixture of gas and air occupies such chamber, then the gas jet outside is ignited
and the flame being propelled into the chamber causes an explosion therein and
thereby through the internal aperture the charge within the cylinder is ignited,
and the piston caused to make its first outward stroke. During this outward
stroke the contents of the cylinder in advance of the piston are expelled through
two valves opening outward, one of them being placed at about three fourths of
the stroke, and the other at the end thereof. When the piston has passed the first
of those two valves and whilst the pressure of the products of combustion (or that
arising from the ignition of the combustible charge) still acting on the piston, is in
excess of that of the atmosphere, escape of such products of combustion takes place
through the said first valve, until by such escape and continued movement of the
piston, the pressure in the cylinder falls below that of the atmosphere, where
upon-the valve is automatically closed (by the atmospheric prossure) and a partial
vacuum is created in the cylinder.
The remainder of that portion of the contents of the cylinder before the piston,
escapes through the valve situated at the end of the cylinder.
A new charge of air and gas is now admitted into the cylinder by one or more
valve or valves and pipe or pipes provided for the purpose, (the air automatically

page_text: by reason of the partial vacuum in the cylinder or combustion chamber, which is
a part of such cylinder, and the gas by means of a pump,) and delivered as close as
possible to the rear position of the piston during about two thirds of its inward
stroke. And in order that the creation of a partial vacuum (above referred to)
may be repeated at the time the piston completes each outward stroke, com-
munication is opened between the combustion chamber or rear part of the cylinder
and a surface condenser, and immediately on the commencement of the return or
inward stroke of the piston, (which is effected by the momentum of the fly wheel)
a communication is also established between such condenser and the front part of
the cylinder, and by the action of the condenser and the inward stroke of the
piston, the combustion chamber is exhausted of all or nearly all the products of
combustion, such as steam and hot air generated by the explosion of the charge.
"These products are considerably reduced in bulk (partly to water) by the action
of the condenser, and in this state are drawn into the front end of the cylinder,
where a portion will lubricate the cylinder and piston to some extent, whilst the
remainder will be expelled therefrom by the succeeding outward stroke of the
piston. By the time that the piston has travelled about two thirds of its inward
or backward stroke, the exhaustion of the combustion chamber will have been
completed, and a new charge admitted as above referred to, will on the completion
of the inward stroke of the piston, have occupied the same.-The communication
between the combustion chamber and the condenser being now closed, there will be
a partial vacuum in the condenser ready for the rapid exhaustion of the products
of another explosion. During the remaining one third of the inward or backward
stroke of the piston, the said new charge becomes slightly compressed so as to form
a cushion, and whilst this compression is taking place, a portion of said charge will
be forced into a tube, through a small aperture in the end thereof. This tubo is
fixed in the side of the cylinder, the outer end being joined to a casing in which is
a hollow valve of cylindrical or other external shape, having a reciprocating
movement in such casing.
This valve is provided with ports or openings near its end, one of which com-
municates with the abovenamed tube, another being opposite to the first named
one, and two others at right angles thereto.-The hollow part of this valve is by
means of a pump charged with a mixture of air and gas, which passes through
perforations or their equivalent in the side of the valve into the interior; During
the inward movement of the valve a portion of such mixture escapes through the
first named openings and becomes ignited by a permanently lighted gas jet, or
other permanent light. While the beforementioned tubo in the side of tho
cylinder is receiving its charge from the cylinder, or that part forming the
combustion chamber, escape of the air previously contained in the tube is provided
for by a passage in the hollow valve or otherwise.
During the backward stroke of the hollow valve, communication of its contents
with the above named lighted gas jet or other light, is cut off, the flame becomes
shut in the hollow of the valve, ignites the contents of such hollow part and
explodes the charge in the tube, and through the small orifice in the end of the
tube, the combustible charge in the cylinder (or combustion chamber) is exploded
and is thus caused to propel the piston outward.
This explosion is arranged to take place when the crank is on the dead point or
centre or thereabout. By the time that the charge of air and gas is exploded and
hot air and steam is generated of sufficient pressure for propelling the piston on its
outward stroke the momentum of the flywheel has changed the position of tho
crank from the dead point to a more favourable ono for impact upon the piston.
During this and subsequent outward strokes of the piston, water and other
residual products of combustion which are (or have been) drawn into the cylinder
through or from the condenser are expelled through the two proviously named
escape valves on the cylinder.
While the piston is travelling the remaining one third or portion of its inward
stroke the exhaust valve or communication between the combustion chamber and

page_text: the condenser is closed, as previously referred to, and the intensity of the partial
vacuum in the condenser is increased by the action of the abovementioned one
third or latter portion of the inward movemont of the piston, and on the piston
commencing its next outward stroke the communication between the condenser
and the front part of the cylinder is closed, thus leaving the condensor in a proper
state for exhausting the products of combustion immediately the communication
between the combustion chamber and the condenser is mechanically opened, such
exhaustion being continued or repeated at every backward stroke of the piston,
removes all or nearly all the products of combustion from the combustion chamber
or cylinder and prepares it or them for tho admission of a complete charge of
combustible mixture at each stroke.
Referring to the accompanying drawings, the same letters refer to the same or
like parts wherever they occur. Fig. 1, Sheet 1, is a plan of a gas motor engine
according to my invention.-Fig. 2, a partial side view. Fig. 3, a view looking at
the rear end of the cylinder, Fig. 4, Shoet 2, is a view on the same side as that
shown in Fig. 2, Sheet 1, the cylinder being in section. Fig. 5, is a view on the
contrary side to that of Fig. 4-a, is the engine bed, which may be of any suitable
form. b, the cylinder, the rear part b₁, of which, forming the combustion chamber,
is about equal in capacity to one half of the working part of the cylinder, less the
volume of the piston, and as described in my Provisional Specification that there
shall be sufficient space behind the piston, when in its backward position in which
to explode a charge of combustible mixture of air and gas. I make such part of
the cylinder, which constitutes the combustion chamber, of the abovenamed
proportional capacity. The advantage being that it admits of no greater a charge
of air and gas than can, or could be completely consumed or exploded during the
time the piston is making its outward stroke, consequently there will be less
products of combustion or of any unconsumed charge to remove from the com-
bustion chamber at each stroke, than if such chamber were made larger, thus
enabling the engine to be worked very economically. A cover is fitted to each
end of the cylinder, the front one 6%, being provided with a stuffing box through
which the rod c, of the piston d, passes, which is suitably joined to the cross-
head e, and connecting rod f, and crank gh, is a valve opening inwards for the
admission of air to the combustion chamber, and is conducted by the pipe i,
to a position immediately behind the piston d, as before referred to, gas
being admitted and supplied by means of a pump j, and pipe, provided with a
check valve, (the use of a pump for this purpose is not new,) and the gas mixing
with the air admitted as abovementioned, the combustible charge is thus formed.
The quantity of gas so admitted is regulated by a governor such as m, actuating
the inlet valve n.-o, is tho "self-starter" shown to a large scale, Fig. 7, Sheet 3, in
longitudinal section, shewing the external orifices p, p, and the internal orifice
also the partition 7, Fig. 9 is an end view, the part t, Figs. 7 and 10, being
removed. Fig. 10, is a front view of the part t, which is movable around its axis
for opening or closing the orifices p, p, as required. When it is desired to start
the engine, the orifices p, p, and p, p, in Figs. 7, 8, 9, and 10, coincide with each
other, and either pair of them may be used for the admission of gas from a nozzle
such as u, the other orifice acting as a vent for the escape of air. Fig. 8, is a cross
section at 8, 8, shewing the partition r, for directing the course of such escape of
air as indicated by the arrow v, Fig. 7. Immediately the "starter becomes
charged with gas by the said nozzle u, a light is applied thereto. This at once
ignites the contents of the "starter," causing an explosion therein, which by means
of the internal orifice q, ignites the first charge in the combustion chamber or
cylinder, (the gas of such first charge having been previously. admitted by the
cock was above referred to) causing an explosion thereof and propels the piston on
its first outward stroke. During the ignition or explosion in the "self-starter,"
part of the products of combustion will escape through the orifices p, p, but this is
of no consequence. After the piston has been started on its first outward stroke,
the part t, Figs 7, and 10, is turned on its axis so as to close the orifices p, p. The
"

page_text: igniter or apparatus for igniting the combustible charge in the combustion chamber
at each revolution of the crank shaft (except when the supply of gas forming part
of such charge, is cut off by the governor m, on the engine attaining an excessive
speed) comprises a tube z, attached to the cylinder in such wise that its inner end
communicates by the orifice y, with the combustible charge at a point immediately
behind the piston when in or about its rear position.
The outer part of this tube is joined to a casing z, which forms the receptacle
for a hollow valve a' of cylindrical or other external shape, and receiving a
reciprocating movement by means of the eccentric, or its equivalent, and the
rod c. The tube z, casing 2, and valve a¹, are shewn to an enlarged scale, in
section, in Figs. 11 and 12, Sheet 3. The said hollow valve is closed at the end
and is provided with ports or openings d', d³, d³, d, near its end as shown, these
openings are at one portion of the stroke of the valve, opon to the atmosphere, one
of them d, at the required moment for igniting the charge in the cylinder or
combustion chamber being in communication with the tube x, by means of the
orifice y', another opening d³, being opposite to the firstnamed, two other
openings d³, and d, being at right angles to the two former.-The hollow part of
this valve al is by means of a pump el, charged with a mixture of air and gas
which pass through perforations for their equivalent in the side of the valve to
the interior. The valve in this view is shown in a position for receiving its charge
from the said pump el, the openings d', d', d³, d', being outside the casings, and
open to the atmosphere. During the time the piston is making its inward stroke
the combustion chamber or cylinder having received its charge of combustible
mixture, a portion of this charge is driven into and charges the beforementioned
tube x, through the orifice y, at the same time expelling the contents, such as air
or products of combustion through the orifice y', and passage gl, along tho side of
the hollow valve or otherwise, into the atmosphere as shewn by the arrow h¹.-
Adverting now to the position of the valve in Fig. 11, a constantly burning gas jet
or other suitable flame Fig. 13, acts on and ignites the mixture of air and gas
escaping from the opening d³, near the end of the valve, and by the time that the
piston has completed its inward stroke, the valve has changed its position to that
shewn in Fig 12, and shut the flame of the ignited gas and air within the hollow
of the valve.
This explodes the whole contents of the valve, and by means of the orifice y',
the charge in the tube x; and the orifice y it communicates the explosion to the
combustible charge in the combustion chamber or cylinder, on the explosion of
which the piston d, is again propelled on its outward stroke as previously
explained. The same operations are repeated at each revolution, so long as the
engine is at work, excepting when by reason of an excessive speed of the engine,
the supply of gas is for a time cut off by the governor m, and the inlet valve n,
Fig. 13, is a cross-section of the cylinder in part, shewing in end view the valve a',
and the constantly burning gas jet or other flame. In Fig. 6, which is a
longitudinal section of the cylinder with the piston in its outward position, thore
is shewn the influx of air through the valve h, and pipe i, the velocity of the entry
carrying the air to the piston, gas following from the pump j, and mixing there-
with.-, is the condenser, also shown to an enlarged scale in Fig. 14, Sheet 3,
through which cold water circulates, Bowing thence through the water jacket of
the cylinder b.-Fig. 15, is a cross-section of the condenser on the line l³, 1ª
shewing the water inlet -The condensor is connected to the rear of the com-
bustion chamber by the pipe m', a check valve n', situated between the combustion
chamber and the condenser, being by the action of a cam o¹, on the crank shaft,
and lever o, or their equivalent, mechanically opened when the piston has
completed its outward stroke and remaining open till the products of combustion
have been exhausted by the condenser and the action of the inward stroke of the
piston as previously described.-The front part of the cylinder is connected to the
condenser at p', and between the two there is a check valve p², this closes
the communication between the front part of the cylinder and the condenser on

page_text: the outward stroke of the piston and prevents the reduced products of combustion
being returned to the condenser. 9, and 1, are the two valves through which a
portion of the reduced products of combustion is expelled by the outward stroke
of the piston, n, is the inlet valve and m, the governor by which the required
quantity of gas for the combustible charge is supplied and regulated. The gas
being passed through and compressed by the pump j.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declaro that what
I claim is
"solf-
1st In a gas motor engine, the apparatus hereinabove described as a
starter," and shewn in Figs 7, 8, 9 and 10, Sheet 3, substantially as described and
for the purpose set forth.
2nd In a gas motor engine, the uso for igniting the combustible mixture, of a
hollow reciprocating valve such as a¹, working in a casing, and provided with
inlets such as f, and ports such as d', d³ d³ d', in combination with a pump from
which gas and air are received, and an igniting tube situated within the combustion
chamber, substantially as described and illustrated in the drawings.
3rd In a gas motor engine, the use of a combustion chamber of about half the
capacity of the working cylinder, less the volume of the piston, substantially as
hereinabove set forth.
4th In a gas motor engine, the use of a condenser such as 1, substantially as and
for the purpose herein described.
5th Causing the piston during about two thirds of its inward stroke, to draw the
products of combustion from the combustion chamber through a condenser, tho
said products of combustion being reduced in volumo by their passage through
the condenser, substantially as described and for the purpose specified.
6th In a gas motor engine, the use for admitting air into the combustion
chamber or cylinder, of pipes or a pipe such as i, each provided with a valve such
as h, and delivering the air close behind the piston as shewn in Figs. 4 and 6 of
the drawings.
7th The combination of parts constituting a gas motor engine such as above
referred to, the whole arranged and operating substantially as hereinabovo
described and shown in the drawings.
Dated this 2nd day of Maren 1859.
Witness,
THO'. E. CRAVEN, C.E.,
Fellow Inst. Patent Agents,
24, Victoria Chambers, Leeds.
JAMES SHAW.