Year: 1886

page_text: Date of Application, 30th Mar., 1886.
Complete Left, 30th Dec., 1886.
Complete Accepted, 29th Mar., 1887
I HENRY THOMAS DAWSON of Salcombe in the County of Devon Gentleman do
hereby declare the nature of this invention to be as follows:-
This invention has for its object improvements in gas engines and applies especially
to a new method of introducing the gaseous fuel into the cylinder of the engine in
such manner that it may there be found everywhere in fine continuous filaments or
sheets always in close juxta position with air but nevertheless not uniformly admixed.
For this purpose I employ an admission apparatus consisting of two tubes placed
concentrically one within the other. The gas is admitted to the narrow space between
the two whilst air is allowed to enter freely through the inner tube. This admission
apparatus delivers the air and gas together to the working cylinder of the engine and
the gas enters the cylinder in the form as it were of a thin coating enveloping the air
which simultaneously enters. At high speeds, the time of charging is so short that
any shape impressed on the entering gas and air practically exists so at the moment
of ignition. I prefer to make the inner tube of this supply apparatus adjustable so
that its extremity can be brought nearer to or further from the entrance to the working
cylinder.
By this means I can cause what I may term the striated arrangement of gas and
air which this supply apparatus brings about to be either more or less completely
preserved in the cylinder itself as I may desire and thereby I am able to regulate the
rate of combustion of the charge in the cylinder.
The air and the gas thus travel in parallel lines as they advance towards the
cylinder, the air moving at high velocity and the gas at low velocity until when the
streams meet the air carries the gas forward with it at its own speed, the stream of gas
hoing proportionally attenuated.

page_text: When the inlet passage to the cylinder closes the momentum of the air checks the
issue of the gas from the annular orifice increasing the pressure which causes the flow
to recommence instantaneously when the passage is again opened.
I apply this improvement to engines such as are described in the Specification of a
former Patent granted to me No. 7920 in the year 1885. But this admission
apparatus is also applicable to other gas engines. In the improved engine the
arrangement of the main cylinder with its end cover and cylindrical projection
thereon and the hollow and elongated piston partially rotating within the main
cylinder remain as before; and as before, there are inlet and outlet openings and
ignition apertures both in the main cylinder and piston. Gas and air from an
apparatus such as I have described enter the main cylinder by one aperture and air
also at the same time is drawn in by another aperture, this goes on until the firing
apertures in the outer cylinder and piston coincide. The piston by the expansion
resulting from combustion of the charge is then driven to the end of its stroke;
afterwards it returns and then other passages in the cylinder piston are brought to
coincide to allow of the escape of the products of combustion. Sometimes I provide
in addition a valve on the cylinder cover consisting of two plates both perforated
around the periphery. When the perforations coincide air can enter the cylinder by
this valve.
The moveable plate is partly rotated to and fro by a cam on the engine shaft.
This valve admits air around the walls of the cylinder encasing the charge and
thereby preventing to a great extent the communication of heat to the cylinder. It
also prevents too great a suction by the ignition port when this is opened.
In order to prevent the cylinder becoming overheated broad webs or flanges are
cast upon it over these a casing is placed and thereby air channels are enclosed.
These can be connected with a flue or chimney and in this manner a rapid current of
air between the webs or flanges on the cylinder is produced, and so the heat is
rapidly imparted to the air and the cylinder kept at a suitable temperature. The
draught may be forced by a fan or the exhaust gases or other means.
I provide these engines with a governor consisting of a vertical axis carrying at its
upper end a shallow bowl like vessel in which metal balls are placed. A cover of
similar form is provided to the vessel and this is pressed downwards with a spring.
The cover then gathers the balls together inwards towards the centre of the bowl. As
the axis rotates the balls are thrown out from the centre by contrifugal force, they pass
towards the periphery of the bowl and thereby the cover is lifted against the resistance
of the spring.
A siem connected with the cover imparts movement to a valve which controls
the quantity of gas entering the engine or shuts it off. The ignition is effected by
a small Bunsen burner kept always alight on the outer side of the ignition port in the
side of the working cylinder.
I also make a double acting gas engine on similar principles to this single acting
engine. The piston is differently constructed and the cylinder is closed at both
ends. The piston is partially rotated and is as before elongated to cover the
admission, exhaust and ignition apertures, it has a piston rod passing through a well.
fitted hole in the cover or a gland. The piston is made hollow and divided in the
centre of its length by a diaphragm carrying the boss for the piston rod socket.
The cylinder is pierced with admission, ignition and exhaust passages in the centre
of its length, or thereabouts, and the piston is cut with passages as in the single
engine, but whereas, in the single engine only one fourth part about, of the
oval track of the cylinder ports upon the partially rotating piston is used,
for the admission ports one point for the ignition port and about one
half of the track for the exhaust: in the double acting engine, two fourths of the
oval is taken up with the admission, one fourth at each end commencing each stroke,
two points are taken for ignition ports, near the middle of each stroke and the
exhaust occupies the greater part of each side of the oval corresponding to the exhaust
passage. The openings cut in the piston are led one complete set, of, admission,

page_text: ignition and exhaust ports, to each end of the piston cavity, so that the cycle of opera-
tions is completed at each end of the cylinder once in each revolution. The ignition
ports near the centre of the piston open one on each side of the diaphragm and are
practically cut straight into the charge cavity.
A single igniting burner serves both ends.
The gas and air are admitted by the annular partially annular or other striating
admission apparatus before described and the same means of cooling by plates or other
surface extentions, assisted by an induced current of air may be employed.
The partially rotative movement of the piston is imparted by an arm upon the piston
rod near the cross head engaging between a pair of lugs on a projection of the con-
necting rod or by a short are on the connecting, rod gearing on part of a pinion on
the piston rod. The piston rod is formed with a cheese head and fitted into the cross
head so that it may revolve in the cross head. The crosshead works in guides as
usual in steam engines and the connecting rod and crank arrangements are also as
usual.
Tel : LALI 100
CARPMAEL & Co.,
Agents for the Applicant.

page_text: I, HENRY THOMAS DAWSON of Salcombe in the County of Devon Gentleman 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
This Invention has for its object improvements in gas engines and applies especially
to a new method of introducing the gaseous fuel into the cylinder of the engine in
such manner that it may there be in fine continuous filaments or sheets always in
close juxta position with air but nevertheless not uniformly admixed.
For this purpose I employ an admission apparatus consisting of two tubes placed
concentrically one within the other. The gas is admitted to the narrow space
between the two whilst air is allowed to enter freely through the inner tube. This
admission apparatus delivers the air and gas together to the working cylinder of the
engine and the gas enters the cylinder in the form as it were of a thin coating
enveloping the air which simultaneously enters. At high speeds the time of charging
is so short that any shape or formation impressed on the entering gas and air
practically exists so at the moment of ignition. The inner tube of this supply
apparatus I sometimes make adjustable so that its extremity can be brought nearer to
or further from the entrance to the working cylinder.
By this means I can cause what I may termi the striated arrangement of gas and
air which this supply apparatus brings about to be either more or less completely
preserved in the cylinder itself as I may desire and thereby I am able to regulate the
rate of combustion of the charge in the cylinder which I do with a view to obtain
complete combustion and to fill the cylinder without terminal pressure.
The air and the gas thus travel in parallel lines as they advance towards the
cylinder, the air moving at high velocity and the gas at lower velocity until when the
streams meet the air carries the gas forward with it at its own speed, the stream of
gas being proportionately attenuated.
When the inlet passage to the cylinder closes, the momentum of the air checks the
issue of the gas from the annular orifice increasing the pressure which causes the
flow to re commence instantaneously when the passage is again opened.
I apply this improvement to engines such as are described in the Specification of a
former Patent granted to me No. 7920 in the year 1885. But this admission
apparatus is also applicable to other gas engines. In the improved engine the
arrangement of the main cylinder with its end cover and cylindrical projection
thercon and the hollow and elongated piston partially rotating within the main
cylinder remain as before; and as before there are inlet and outlet openings and
ignition apertures both in the main cylinder and piston. Gas and air from an

page_text: apparatus such as I have described enter the main cylinder by one aperture and air
also at the same time is drawn in by another aperture: this goes on until the firing
apertures in the outer cylinder and piston coincide. The piston by the expansion
resulting from combustion of the charge is then driven to the end of its stroke;
afterwards it returns and then other passages in the cylinder and piston are brought
to coincide to allow of the escape of the products of combustion.
Sometimes l
provide a valve on the cylinder cover consisting of two plates both perforated around
the periphery. When the perforations coincide air can enter the cylinder by this
valve.
The moveable plate is partly rotated to and fro by a can on the engine shaft.
This valve admits air around the walls of the cylinder encasing the charge and
thereby preventing to some extent the communication of heat to the cylinder. It
also prevents too great a suction by the ignition port when this is opened.
In order to prevent the cylinder becoming overheated broad webs or flanges may
be cast upon it.
I provide these engines with a governor consisting of a vertical axis carrying at its
upper end a shallow bowl like vessel in which metal balls are placed. A cover of
similar form is provided to the vessel and this is pressed downwards with a spring.
The cover then gathers the balls together inwards towards the centre of the bowl. As
the axis rotates the balls are thrown out from the centre by centrifugal force, they
pass towards the periphery of the bowl and thereby the cover is lifted against the
resistance of the spring.
A stem connected with the cover imparts movement to a valve which controls the
quantity of gas entering the engine or shuts it off. The ignition is effected by a
small burner kept always alight" on the outer side of the ignition port in the side of
the working cylinder.
I also make a double acting gas engine on similar principles to this single acting
engine. The piston is differently constructed and the cylinder is closed at both ends.
The piston is partially rotated and is as before elongated to cover the adinission,
exhaust and ignition apertures. It has a piston rod passing through a well fitted
hole in the cover or a gland. The piston is made hollow and divided in the centre of
its length by a diaphragm carrying the hoss for the piston rod socket.
The cylinder is pierced with admission, ignition and exhaust passages in the centre
of its length or thereabouts, and the piston is cut with passages as in the single
engine, but whereas in the single engine only one fourth part about of the oval track
of the cylinder ports upon the partially rotating piston is used, for the admission
ports, one point for the ignition port and about one half of the track for the exhaust;
in the double acting engine, two fourths of the oval is taken up with the admission ;
one fourth at each end commencing each stroke, two points are taken for ignition
ports, near the middle of each stroke and the exhaust occupies the greater part of each
side of the oval corresponding to the exhaust passage. The openings cut in the piston
are led one complete set, of admission ignition and exhaust ports, to each end of the
piston cavity, so that the cycle of operations is completed at each end of the cylinder
once in each revolution. The ignition ports near the centre of the piston open one
on each side of the diaphragm and are practically cut straight into the charge cavity.
A single igniting burner serves both ends.
The gas and air are admitted by the annular partially annular or other striating
admission apparatus herein described.
The partially rotative movement of the piston is imparted by an arm upon the
piston rod near the cross head engaging between a pair of lugs on a projection of the
connecting rod or by a short are on the connecting rod gearing on part of a pinion
on the piston rod. The piston rod is formed with a cheese head and fitted into the
cross head so that it may revolve in the cross head. The cross head works in guides
as usual in steam engines and the connecting rod and crank arrangements are
also as usual.
In order that my said invention may be fully understood and readily carried into
effect I will proceed to describe the drawings hereunto annexed.

page_text: Figure 1 is a side elevation.
Figure 2 is a plan.
Figure 3 is a front elevation, and
Figure 4 is a rear elevation of a single acting engine constructed according to
my invention; it is similar except as herein explained to the engine described in
the Specification of my former Patent.
Figure 5 is a development full size of the exterior surface of the piston.
Figure 6 is a development of the interior surface of the cylinder.
Figure 7 is a plan of the piston.
Figure 8 is a longitudinal section of the same
end cover, and
shewing also the cylinder &
Figure 9 is a section on the line 1, 1, in Figure S.
Figure 10 is a section of the gas admission apparatus.
Figure 11 shows a similar gas admission apparatus but made capable of adjust-
ment.
Figure 12 is an elevation of the governor.
Figure 13 is a section of the same.
Figure 14 is a side elevation and
Figure 15 is an end elevation illustrating the application of an air valve upon 2
the end cover of the cylinder.
Figure 16 is an elevation.
Figure 17 is a plan and
Figure 18 is a longitudinal section of a double action gas engine constructed
in accordance with my invention.
Figure 20 is an elevation of the piston full size.
Figure 21 is a development of the piston surface.
Figure 22 is a development of the interior surface of the cylinder.
Figure 23 is an end elevation of the piston.
Figures 24 and 25 are transverse sections on the lines 1, 1, and 2, 2 of 3
Figure 20.
Figures 26 to 33 are longitudinal sections of the piston taken respectively on
the lines 1. 12. 2. &c. in Figure 21.
Figure 34 is an elevation showing the joint between the piston rod the cross-
head and the connecting rod.
3
Figure 35 is a section on the line 3, 3, in Figure 34; and
Figure 36 is a section on the line 4, 4, in Figure 35.
A is the cylinder; it is shown with flanges A' cast upon it to aid in the diffusion
of heat and these flanges may if desired be enclosed by a sheet metal or other casing
through which air is passed where necessary and in larger engines other and 4
ordinary means of cooling may be employed.
B is the piston. C is the connecting rod. D is the crank axis and the crank
pin.
At C is a ball at the end of the connecting rod it is received into a corresponding
socket on the piston. At C is an arm on the connecting rod terminating in a pin
which enters a hole in the cylindrical plug and this plug is fitted into a socket
prepared for it in the horn B projecting from the piston. In consequence of this
connection the piston is so controlled that each point in its surface travels in an oval
course dois on Figure 5 indicate points which successively coincide with the angle
marked of the ignition port in the cylinder.
The gas enters the cylinder through the apparatus E shown also by Figure 10 after
first passing a regulating tap and also a valve controlled by the governor.
5
A is the admission port on the under side of the cylinder, and when the admission
port B in the piston coincides with A² the charge enters the cylinder. Air also
enters the cylinder by the port A³ when the corresponding port B³ in the piston comes 5
to coincide with it. This air admission continues until the ignition takes place. The

page_text: purposes which it serves are as follows:-it maintains an approximate equality of
pressure within and without the cylinder which greatly facilitates the ignition, and
besides it still further attenuates the striation produced by the gas and air admission
apparatus, it causes a more perfect combustion and it takes up heat when expanded
by the charge producing work. The ignition is effected when the port A in the
cylinder coincides with the port B in the piston. A flame is kept constantly burning
at the port A*.
A and B are the exhaust ports in the cylinder and piston respectively; the
exhaust takes place when these coincide, they do so throughout the return stroke of
the engine which results from the momentum of the fly-wheel D² on the axis D).
F is a burner tube to which gas is admitted by a nozzle F. Air enters a hole F
in the side of the tube and gas and air mixed burn on the wire gauze F³ which closes
the top of the tube F. is a small tube by which some of the gas and air passes to
supply a flame to relight the gas at F³ if ever it should be blown out in lighting the
charge in the cylinder.
In Figure 10 the gas enters by the pipe El and ascends by the annulus between
the two tubes E2 and E. The inner tube E³ terminates at a considerable distance
below the top of the outer tube E at a point which has been found by experiment
suitable to ensure the most favorable condition of the charge in the cylinder and I
would here remark in respect to this admission apparatus which constitutes an
important feature in my present invention that it is essential that the gas and air after
having been arranged in parallel currents should then flow direct into the cylinder
either by a straight passage or if not absolutely straight by a passage of easy
curvature so that the desired arrangement having been obtained may not be lost
before reaching the cylinder.
Any impediment which suddenly deflected the currents would cause such a
complete admixture of the gas and air as would defeat the object I have in view,
which is that the air and the gas should be present in the cylinder in more or less
separate filaments or currents neither too much separated nor too much admixed. It
is obviously not essential that the gas admission should be by a complete annulus
between cylinders E and E³ it is sufficient if the gas and air are brought together
in parallel streams and are not afterwards caused to lose this arrangement by
obstacles in the channel which leads the air and gas into the cylinder.
In Figure 11 the inner tube E3 of the gas supply apparatus is adjustable by means
of a rack and pinion.
G is the governor; it consists of a bowl G¹ mounted on a stud axis and caused to
revolve by frictional gear consisting of the smooth pinion Gand the intermediate
elastic faced wheel G3 which is in contact with a disc on the main axis D. G₁ is
another bowl pressed towards G¹ by the spring G5 and there are balls G between the
two bowls. A rod G7 passes down from the bowl G₁ to a valve G. This valve is
double acting and is adapted to close against two seats one above and the other below.
When the governor is at rest and the balls G6 are grouped around the centre the
valve closes against its lower seat and prevents the flow of gas. Again when the
engine is running and the speed becomes excessive the valve closes against its upper
scat and again cuts off the gas; between these extreme positions the governor
regulates the flow.
The governor above described is applicable to other gas engines. Other governors
also may be adapted in the manner described to cut off the gas either when the engine
stops or its speed is excessive, and to regulate the flow under other conditions.
In engines of considerable size it is desirable to apply an air valve on the end cover
of the cylinder admitting air in streams along the walls of the cylinder and charge
cavity in the piston and so in some degree preventing contact between the gas charge
and the walls. The cylinder cover is perforated around the periphery and a plate H
is applied within it provided with similar perforations it is mounted as a rotary slide
and has an arm H¹ upon it. The arm is forked at the end to receive the extremity of
another lever He having its fulcrum at H2*. A bowl at the further end of the lever H

page_text: runs on a cam surface H³ on the main shaft being held against it by a spring. The
form of the cam is such that air can enter the cylinder by the holes in the plate H
whilst the cylinder is receiving its charge and until the ignition takes place; then the
passages are closed to open again for the next stroke. The sheet of air admitted by this
valve lines the walls of the cylinder and takes up and usefully employs heat which
otherwise would be imparted to the walls of the cylinder it also operates in the same
way as the air admitted by the air ports A³ B³; the valve at the cylinder end may be
employed as a substitute for them.
In the double acting engine d is the cylinder and are projections on the end
covers of the cylinder, is the piston, it has in this case a rod fixed to it.
is the connecting rod and d is the crank axis. The piston rod terminates in a
cheese heal which is received into a cavity in the crosshead e'. is a fork at the
end of the connecting rod projecting beyond the joint pin and holding the ball c³ so
that the ball is able to rotate and also to play a short distance longitudinally. There
is a hole in the hall and this receives the end of arm 3 on the piston rod.
The result of this method of connection is that every point in the surface of the
piston describes an oval-that described by the centre of one of the ignition ports.
In the cylinder a, a², is the port by which gas and air in striated arrangement are
admitted; the construction of the admission apparatus e is already described. The
gas and air together pass either to one side or the other of the central partition in the
piston by the piston ports when one or other of these coincides with the port a².
Air enters at the same time as the gas and air by separate ports viz: a" in the cylinder
and in the piston.
The air admission by the port a goes on at each stroke until the ignition takes
place and then the port is closed by the piston.
The firing port in the cylinder is at a and the corresponding poris in the piston at
68, these besides passing directly through the walls of the piston are connected by
channels on the face of the piston with the ports 66. It is necessary as the drawing
indicates that one of these passages should be tunnelled under the surface of the
piston.
the corresponding passages in the
a is the exhaust passage in the cylinder and
piston.
The routine in working for each half stroke is as follows; ports a² and come to
coincide and striated gas and air enters the cylinder; also ports and 5 coincide
and air enters. Presently the gas admission ceases the ports a and separating:
then the ignition ports a and come together and the flame from the lighting
burner enters the cylinder. Immediately the air and ignition ports a³ and 7, close
and the stroke is completed.
During the return of the piston the ports a and 7 are together and the products of
combustion are expelled.
These engines may be made either horizontal oblique vertical or inverted.
It will thus be seen that although the engine is double acting my arrangements are
such as to avoid the complication which would result from doubling the number of
ports in the cylinder; which are no more than in the single acting engine. One
firing flame also serves for both ends of the cylinder.
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 :-
1. A gas engine in which gas and air together are admitted to the cylinder by
passages in juxta-position and flow together in contact from such passages into the
cylinder without check or impediment so that gas and air may be present in the
cylinder in a striated form, the gas and air being every where in close proximity and
yet not uniformly admixed substantially as described.
2. A gas engine in which gas and air admitted together to the cylinder by one
passage and air alone by another passage and in which this latter passage is kept open
until the charge is ignited substantially as described.

page_text: 3. A gas engine with an adjustable gas and air admission apparatus in which
gas and air flow in parallel passages and come together before entering the cylinder
at a distance therefrom which can be regulated substantially as described.
4. A gas engine in which an air valve is provided on the cylinder cover which
is open whilst the cylinder. is charging and which admits a sheet of air lining the
walls of the cylinder; substantially as described.
5. A gas engine provided with a governor consisting of rotating dises or bowls
holding balls or rollers between them which when moved outwards from the centre by
centrifugal force separate the discs or bowls against the resistance of a spring or its
equivalent and thereby control the gas valve substantially as described.
6. A gas engine provided with a governor controlling the gas valve whilst the
engine is running and closing it when the engine stops substantially described.
7. A double acting gas engine having a cylinder and a piston traversing within it
and also oscillating or turning to and fro and having in the cylinder one set of
admission and exhaust ports and in the piston two sets of such ports substantially as
described.
8. A double acting gas engine in which there is one ignition port in the cylinder
and one igniting flame serving to fire the charges at both ends of the cylinder
substantially as described.
9. Gas engines substantially as described and represented by the annexed drawings.
n
2012 1
1000
CARPMAEL & Co.,
Agents for the Applicant.