Improvements in Gas or Combustible Vapour Motor Engines.
Year: 1890

page_text: Date of Application, 21st Apr., 1890
Complete Specification Left, 21st Jan., 1891-Accepted, 21st Feb., 1891
PROVISIONAL SPECIFICATION.
Improvements in Gas or Combustible Vapour Motor Engines.
I JOHN HENRY HAMILTON of Stapleford in the County of Nottingham
Engineer do hereby declare the nature of this invention to be as follows:-
In the type of gas or vapour engine wherein the motor piston makes one
effective stroke in two revolutions when working at full power, it is usual to retain
some of the products of combustion in the cylinder to mix with the incoming
charge.
The object of this invention is the construction of an engine in which these
products of combustion shall be replaced by pure air and in which this shall be
effected in a simple and mechanically efficient manner.
For this purpose I connect or cast with the motor piston a larger piston which is
formed also to act as a guide block and which reciprocates in a cylinder cast as
part of the bed plate. To the back of this cylinder and concentric and in line
with it I bolt the motor cylinder provided with the usual water jacket.
The space between the two pistons acts as an air pump to slightly compress air
and force it through the combustion chamber at the end of the motor cylinder
during the latter part of the exhaust stroke.
I prefer to admit this air through the admission valve which admits the com-
bustible mixture to the combustion chamber and which may be in communication
with a passage cast upon the motor cylinder and leading from the space between
the two pistons. The latter space also communicates freely with a chamber in the
bed plate provided with an air inlet valve. This chamber and the passage above-
mentioned have the effect of increasing the clearance space of the air pump and in
some cases I propose to make the clearance from three to five times the effective
pump capacity so that if a self-acting non return inlet valve be used the pressure
in the clearance space shall not rise more than about five pounds per square inch
above atmospheric pressure on the compression stroke of the motor piston.
The air thus compressed re-expands on the next outward or explosion stroke and
on the next inward or exhaust stroke is first compressed to about two pounds per
square inch above atmospheric pressure and then (when the admission valve is
opened) discharged into the combustion chamber part of it escaping through the
exhaust valve which is kept open till after the crank has passed the back centre.
In some cases it may not be convenient to construct such a large clearance space
and then instead of the self-acting non return air inlet valve for admitting air to
the pump I propose to substitute a valve operated from the usual side shaft which
gives movement to the other valves, the said valve being held open during the com-
pression stroke, the 'explosion stroke and the greater part of the suction stroke and
closed during the entire exhaust stroke.
In order to reduce the resistance to the passage of air through the valve I make
the area of valve opening much larger than usual and may adopt any one of the
valves described below.
The self-acting non return air inlet valve may consist of long narrow strips of
rubber or leather secured to the valve seat by longitudinal holding down bars
passing over the centre of each strip so as to leave its edges free to lift; a long
narrow slit on each side of the holding down bar forms a valve port and the valve
may be stiffened over this port by means of thin metal strips rivetted on to its
upper surface.
A convenient form of valve when not self acting is an oscillating Corliss valve
with double or treble ports and operated from an eccentric on the side shaft in such
a manner that it will remain open during the greater part of the suction, the

page_text: whole of the compression and explosion strokes, and be closed during the exhaust
stroke.
Or this air inlet valve may be of the lifting type in which case I prefer to
construct it in the form of concentric rings covering annular ports and thus while
using a small lift obtain a large area of opening. In this case a cam may be used
to operate the valve.
The gas inlet valve may take the form of an annular ring concentric with the
admission valve and surrounded on its outer circumference by the air ports and
operated by means of the two spindles one on each side of the admission valve
spindle.
Both valves may be operated by one lever if provision be made to allow the
admission valve a certain amount of lift before the gas inlet valve begins to lift as
by securing a cross head to the admission valve spindle adapted to come against the
ends of the gas inlet valve spindles or collars on the same.
When the above arrangement is adopted I propose to arrange the above valves
with their axes in a radial and horizontal position and the exhaust valve in a radial
and vertical position below the cylinder the side shaft being thus situated between
the exhaust and admission valves.
To govern the speed of the engine I propose to form two cam tracks one of
which is adapted to give the necessary motions to the admission valve when the
engine is not making any ignitions and the other to give the extra lift at the proper
time for opening the gas inlet valve. The roller which runs on one or other of
these cam tracks may be secured to a sliding spindle having at its other end a
bevelled disc so arranged that it shall when the engine exceeds its proper speed
come in contact with a spiral projection or cam formed on or attached to a
balanced frame which with suitable springs being pivotted to the side shaft and
revolving with the latter forms the centrifugal governor. This balanced frame is
similar to that described in Rollason and Hamilton's Complete Specification
Number 3546 of the year 1888.
;
Or
A light spring may be used to keep the roller above mentioned on one of the
cam tracks except when increase of speed causes the spiral projection to come into
operation and to force the roller over to the other track against the action of the
spring and in this case a raised rib between the tracks may serve to keep it on the
proper track during the remainder of the cycle, the rib being cut away for a
portion of the circumference corresponding to the spiral projection or cam.
instead of the light spring a switch piece may be arranged in connection with the
bevelled disc above mentioned in such a manner that it will bring the latter into
proper position to be acted on by the spiral projection or cam whichever track the
roller has run upon during the preceding part of the cycle. I do not however
propose to confine myself to the use of the governing arrangement above described
as the governing as well as the ignition may be effected in any known manner.
The cylinder lubricator may be operated by means of the slight variations of
pressure obtaining in the air pump space between the motor and blowing pistons.
For this purpose a hole or pipe may put the air space of the lubricator in permanent
connection with the pump space and the top or a portion of the top of the lubricator
may be formed of a flexible diaphragm or piston to which is attached a needle or
valve and the extent of the movement of the latter may be adjusted by means of a
set screw or plug.
I prefer that the end of the motor cylinder should project into the larger or
blowing cylinder and should have an oil receptacle or cup formed on its upper side
into which the oil from the needle shall drop, the oil that drops off the lower side
serving to lubricate the bottom of the larger cylinder.
To apply the above improvements to the engine known as Crossley's twin engine
it would be convenient to allow a free communication to exist between the pumping
space of the two cylinders and to reduce the discharging capacity of each of these
spaces and to keep the air inlet valve closed during each back stroke of the pistons
the air being discharged alternately through the two combustion chambers.

page_text: If the air inlet valve be of the Corliss type above described it may in this case
be operated from an eccentric on the crank shaft instead of one on the side shaft.
Dated this 21st day of April 1890
AYRTON & THOMAS,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Gas or Combustible Vapour Motor Engines.
1 JOHN HENRY HAMILTON of Stapleford in the County of Nottingham,
Engineer, do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement :-
In the type of gas or vapour engines in which the motor piston makes one
effective stroke in two revolutions when working full power it is usual to retain
some of the products of combustion in the cylinder to mix with the incoming charge.
The object of this invention is the construction of an engine in which these
products of combustion shall be replaced by pure air and in which this shall be
effected in a simple and mechanically efficient manner.
I shall now proceed to describe the way in which I accomplish this result referring
to the accompanying drawings in which
Fig. 1 represents a sectional elevation and Fig. 2 a sectional plan of my improved
engine.
Fig. 3 a transverse section through the admission and exhaust valves on
line, a, a, a, (Fig. 2).
Fig. 4 a transverse section at line, (Fig. 2).
Fig. 5 a transverse section on enlarged scale through motor cylinder and governor
at line,, (Fig. 2).
Fig. 6 a side elevation of governing mechanism.
Fig. 7 an end elevation of admission cams.
Fig. 8 a sectional plan of governor at line d, d, (Fig. 5).
Fig. 9 a section of roller and pin at line u, u, (Fig. 6).
Fig. 10 a transverse section of the non-return air inlet valve F (Fig. 1).
Figs. 1 and 12 represent transverse sections through cylinders showing an
alternative form of air inlet valve.
In these figures A is the motor cylinder provided with admission valve H and
exhaust valve G.
This cylinder is bolted to the back end of a somewhat larger cylinder B which
forms part of the bedplate of the engine. A differential piston C reciprocates in
these cylinders and is formed with a long slipper at its front end for receiving the
lateral thrust due to the obliquity of the connecting rod. It is provided with
suitable packing at its back end to resist the high pressure of the gases in A. and
may have a light packing ring at the front end to prevent the escape of the low
pressure air in B.
A chamber D is formed in the bedplate and is always in free communication with
the pump cylinder B and with the back side of the admission valve H by means of
the passage E (Figs. 2 and 4).
An air inlet valve F allows a free admission of air to the chamber D and to the
passage E.
A gas valve K arranged as described in Hamilton and Rollason's Complete
Specification No. 16434 admits combustible gas or vapour behind the admission
valve H. Supposing the suction or charging stroke to be commencing I shall now
describe the action of the engine, when igniting at every fourth stroke.
The admission valve H being open air is drawn through the valve F into the
chamber D thence passing through the passage E to the cylinders A and B. I
may cause the admission valve H to close before the stroke is completed and in
this case during the remainder of the stroke air is drawn into the cylinder B only.

page_text: On the return stroke the combustible charge is compressed in the cylinder A in
the usual manner and the air in cylinder B is also compressed but to a much smaller
extent. At the beginning of the next outward stroke the charge is ignited in
cylinder A and the air compressed in cylinder B and clearance spaces re-expands.
The exhaust valve is opened near the end of this stroke and the motor piston
returning expels a portion of the products of combustion while the air is re-com-
pressed in cylinder B and clearance spaces till the pistons have completed the
greater part of the stroke.
The admission valve H is now opened the exhaust valve being still open and the
gas valve closed, the air compressed in passage E and clearance spaces rushes in
mixing with and sweeping out the products of combustion from the rear end of
cylinder A.
The exhaust valve is kept open till after the crank has passed its back centre
thus giving time for the replacement of the products of combustion by pure air
which continues to flow in till the exhaust valve closes, the gas valve is then
opened and the explosive mixture enters the cylinder. I consider it to be essential
to the practical success of the engine that the pressure in the cylinder B should be
low so that the power lost in compressing the air during the exhaust stroke may be
trifling and also that there may be no elaborate fitting required to prevent leakage.
In my Provisional Specification I mentioned 5 lbs. per square inch above atmosphere
as a maximum pressure in cylinder B but consider it may be kept less with
advantage.
To effect this object the clearance spaces are made sufficiently large and I
construct the differential piston C with ribs as shewn in Figs. 1 and 2 to connect the
motor with the pump piston so that the common interior of the cylinders A and B
forms a considerable clearance space and together with the spaces D and E con-
stitutes a clearance space with a capacity several times greater than the effective
pump capacity by which I mean the difference in the areas of the pistons multiplied
by the stroke.
To reduce the resistance to the entrance of air to the cylinder B I make all the
passages of large area and with the same object I may use the inlet valve shown in
Fig. I at F and in Fig. 10. This consists of a metal grid having the ports covered
by rubber or leather strips a held down by metal bars & secured to the grid by
screws. The rubber or leather may be stiffened over the ports by metal strips
rivetted on to their top sides.
In some cases it may not be convenient to have a clearance space of sufficient.
capacity and I may instead of using a non-return valve have a valve to allow the
air to pass out of cylinder B during the compression stroke of the motor piston.
A. convenient form of valve for this purpose and method of working it are shown
in Figs. 11 and 12.
This consists of a Corliss valve L caused to oscillate in the bedplate by means of
an eccentric M operating a crank arm secured to the valve spindle. The eccentric
is secured to the lay shaft which operates the other valves.
The Corliss valve remains open during the suction, compression and explosion
strokes and is closed during the exhaust stroke thus admitting air to the cylinder B
or allowing it to escape into the atmosphere.
In this case I prefer to open the admission valve H much earlier in the exhaust
stroke as the pressure of the air in the cylinder B will rise more rapidly owing to
the smaller clearance spaces; and will sooner be sufficient to overcome the slight
back pressure of the exhaust in cylinder A.
Whether the air inlet valve be non-return or return the admission valve may be
opened when the pressure in B is about 2 lbs. per square inch above atmosphere.
It is obvious that the Corliss valve might be used as a non-return valve; or
other forms of valve might be adopted but I have described those which I consider
the best.
For large engines the Corliss valve might have double or treble ports so as to
give ample passage area.

page_text: and the governing mechanism.
To the end of the admission valve spindle I secure a crosshead J Figs. 2 and 6.
The ends of the spindles which operate the gas valve K pass through holes in this
crosshead and have collars formed on them in such a way that the admission valve
may have a certain amount of free lift before the crosshead comes in contact with
the collars.
The admission valve is operated by a lever I having a roller at its lower end.
This roller may run on one or other of two cams N and P on the lay shaft the
former being adapted to give the necessary motions to the admission valve when no
ignition is to occur and the latter to give the extra lift required to open the gas
valve.
I have already described the cycle of operations when an ignition takes place at
every fourth stroke the roller being upon the cam P and I shall now describe the
cycle of operations which I consider best when the engine is working at less than
full power and ignitions are to be cut out."
Supposing the engine to be commencing its exhaust stroke the exhaust valve G
will be open and the admission valve H. closed and these conditions will be
maintained during the whole of the exhaust stroke. The exhaust valve will close
early on the next outward or suction stroke and the admission valve H will open
almost simultaneously and will remain open all the time the exhaust valve remains
closed that is during the suction, compression and greater part of explosion stroke.
The effect of this will be that the air compressed in cylinder B and clearance spaces
will first re-expand into cylinders A and B till the pressure is slightly below
atmospheric pressure then air will enter through the valve F during the remainder
of the suction stroke.
On the compression stroke the air will be compressed in cylinders A and B and
clearance spaces the pressure being higher than the pressure in B when ignition is
about to occur though much lower than that of the compressed mixture in A. under
the same condition.
During the next outward or that corresponding to the explosion stroke, the air
re-expands into cylinders A and B and near the end of this stroke the valve H is
closed and the exhaust valve opened and the air in cylinder A discharged through
it on the return stroke while the air in B is compressed therein and in the clearance
spaces in the same way as if an ignition had occurred the cams N and P being of
the same shape at the parts corresponding to this portion of the cycle as shewn in
Fig. 7.
If the speed of the engine shall now have fallen sufficiently the roller will be
transferred to the cam P during this exhaust stroke but if the speed is still too
high it will again run on the cam N and the last described cycle of operations will
be repeated.
By adopting the above method of governing 1 overcome the difficulty which
occurs when the explosive mixture is cut off before the end of the suction stroke
whereby a loss of power when cutting out ignitions results from the pressure behind
the piston being less during the latter part of the outstroke than during the same
part of the return stroke. This effect is shown by "a negative loop
indicator card.
::
on the
If the mixture is admitted up to the end of the suction stroke I may cause the
admission valve to open and close at the same points in the cycle whether ignitions
are to take place or not, the only difference being that in the former case the
admission valve receives an extra lift at the proper time thereby opening the gas
valve.
I shall now describe the mechanism for transferring the roller from one cam to
the other as determined by the speed of the engine.
This roller R is mounted on a sliding spindle S, Figs. 5, 6, 7 and 9, which is
prevented from turning by means of a cotter or feather and has formed on or
attached to its end a wedge piece t.

page_text: A drum secured to the lay shaft has two projecting pieces w, w with inner
inclined faces secured to it. The distance apart of these projecting pieces is such
that the thin end of the wedge piece shall enter the space between them whether
the roller is on the cam N or P. The thick end of t can just pass through the
narrowest part of the opening and the roller is thus switched into mid position at
every revolution of the lay shaft. Another wedge or spiral cam piece is attached
to a balanced frame Q pivotted in the drum O Figs. 5 and 8.
This balanced frame is similar to that described in Rollason and Hamilton's
Specification No. 354688.
A spring resists the centrifugal force of the revolving masses Q and tends to
keep the wedge or spiral cam piece pressed over towards the cams N and P. In
this position the thin end of the wedge passes to the left of the edge of wedge t
Fig. 6, as the latter leaves the space between wand w and so causes the roller to
be pulled over on the cam P. On the contrary should the centrifugal force overcome
the resistance of the spring the wedge will pass on the right side of t and thus the
roller will be pushed over on cam N. A. raised rib V between the cams N and P
serves to keep the roller on one track during the whole of the cycle except that part.
corresponding to the exhaust stroke during which the roller is shifted from one
cam to the other.
The wedge piece t occupies the same position on the spindle S and acts in the
same way as the thin roller described in my Provisional Specification.
I have not here described the arrangement in which the roller is kept on the
cam by means of a spring as described in my Provisional Specification because I
consider the herein before described arrangement to be more suitable.
The ignition of the charge may be effected in any known manner.
For lubricating both cylinders I prefer the arrangement shewn in Fig. 1.
A groove or oil receptacle is formed in the projecting end of cylinder A.
Above this groove is the lubricator provided with a needle valve T which has a
piston at its upper end adapted to work in a hole bored in the cover of the lubricator.
A hole puts the interior of the lubricator in permanent connection with the
cylinder B so that the slight variation of pressure or pulsations in the latter cause
the piston to pulsate and so feed oil down past the needle.
Most of this oil will drop into groove but some may drop on the top of the
large part of the piston C when the latter is full back. The oil that drops off the
lower front edge of cylinder A serves to lubricate the bottom of cylinder B. An
adjustable cap may be used to limit the movement of the needle and so regulate
the supply of oil. Obviously a diaphragm might be attached to or bear against
the end of the needle T instead of the piston. A hole allows the oil that drops
into groove
to pass into the cylinder A or to the piston working therein.
The above described improvements might be applied to double engines as for
instance to the engine known as Crossley's twin engine in which case it would be
convenient to duplicate the pump cylinder B and reduce its discharging capacity
to one half; the capacity of the clearance spaces being the same as for a single
cylinder.
Or if the air inlet valve be of the Corliss type it may be worked from an
eccentric on the crank shaft instead of on the lay shaft.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I would have it understood
that I am aware the use of a differential piston, whether for charging the motor
cylinder with combustible mixture or air only is not novel, nor is it novel to
introduce air during the exhaust stroke for the purpose of clearing out the products
of combustion but what I consider novel and therefore claim is
1. In gas or combustible vapour engines of the four stroke type the use of a
large clearance space in free and permanent connection with an enlarged cylinder
in front of the motor cylinder and with the back of the admission valve to motor
cylinder, and provided with an automatic or non automatic non return air inlet

page_text: valve substantially as and for the purposes described with reference to Figs. 1, 2,
3 and 4 of the accompanying drawings.
2. In gas or combustible vapour engines of the four stroke type the use, in con-
nection with an enlarged cylinder in front of the motor cylinder, of a valve operated
from the lay shaft in such a manner that it permits a free access of air to the
enlarged cylinder and clearance spaces during each forward stroke and a free exit
of air during the compressing stroke but remaining closed during the whole or
greater part of the exhaust stroke, substantially as described and illustrated with
reference to Figs. 11 and 12.
3. In gas or combustible vapour engines the method of operating the admission
and gas valves by one lever provided with a sliding roller the said roller being
adapted to run on one or other of two cams; whereof one gives the admission valve
the series of motions suitable when the engine is running without making ignitions
and the other the series of motions suitable when a charge of gas is to be admitted
substantially as described with reference to the accompanying drawings.
4. In gas or combustible vapour engines the mechanism for effecting the transfor
of the sliding roller referred to in the last claim consisting of a switch operating a
wedge piece or thin roller attached to the spindle carrying the sliding roller so as
to bring this wedge piece on this roller into the proper position to be acted on by
another wedge picce revolving with the lay shaft the latter wedge piece being
arranged to have a slight lateral movement communicated to it by the governor
substantially as described with reference to Figs. 5, 6, 7, 8 and 9 of the accom-
panying drawings.
5. The modification of the above in which the sliding roller is kept on the cam P
by the action of a spring unless forced over on the other cam by a revolving wedge
or spiral piece capable of receiving a slight lateral movement from the governor,
substantially as hereinbefore described.
6. The combination of parts constituting my improved valve operating and
governing device as illustrated by Figs. 5, 6, 7, 8, and 9 or any mere modification
thereof.
7. An engine constructed according to my first claim and arranged to carry out
the following cycle of operations when "cutting out an ignition." (!) Expelling
the products of combustion or air from the cylinder A. and compressing the air in
cylinder B and clearance spaces during the exhaust stroke. (2) Expanding the
air compressed in cylinder B first in cylinder B then (when the exhaust valve
closes and the admission valve opens at an early point of the outstroke) expanding
in both cylinders A and B till the pressure falls below atmosphere when air enters.
through the air inlet valve during the remainder of the outward stroke. (3) On
the third stroke or second inward stroke compressing the air by both pistons there
being a free communication between the cylinders A and B through the open
admission valve. (4) During the fourth stroke or second outward stroke being
that corresponding to the explosion stroke expanding the air in both cylinders there
being still a free communication between them.
8. The arrangement for lubricating the cylinders substantially as described and
illustrated in Fig. 1 of the accompanying drawings.
Dated this 20th day of January 1891
J. H. HAMILTON.