Improvements in Compound Gas Engines, in part applicable to other Gas Engines.
Year: 1892

page_text: Date of Application, 30th Sept., 1892
Complete Specification Left, 28th July, 1893-Accepted, 2nd Sept., 1893
PROVISIONAL SPECIFICATION.
Improvements in Compound Gas Engines, in part applicable to
other Gas Engines.
We, JOHN WILLIAM HARTLEY, of 2 Henrietta Street, Kilmarnock, Engineer,
and JOHN KERR, Engineer, a member of the Firm of Dick, Kerr and Company,
Britannia Engineering Works, Kilmarnock, both in the County of Ayr, do hereby
declare the nature of this invention to be as follows:-
Our invention relates to improvements in the arrangements of compound gas
engines and its object is to provide means of starting and igniting passing hot gases
from the high pressure to the low pressure cylinder with a minimum loss of heat
and also to provide a valve arrangement communicating with an igniter tube of
such nature as to render premature ignitions from leakage an impossibility.
ignite the compressed explosive mixture after the crank has passed the centre
instead of on the centre as is usual, and at the same time compress the products of
combustion in the second cylinder and passages leading thereto.
We
In carrying the first part of our invention into effect we construct a valve suitable
for connecting between the high and low pressure cylinders in the following
manner :-
We arrange between the two cylinders a valve casing containing a bored out
cylinder and we connect to the interior of the said cylinder from both high and low
pressure cylinders by straight ports of ample area which ports are made as short
as possible.
Within the bored out valve cylinder we place a circular valve which valve fits
the said cylinder accurately and has a straight port right through it opening to the
straight ports in the high and low pressure cylinders.
This circular valve consists of a valve frame and two covering valves. The
covering valves close the opposite port openings respectively, and when the frame
is rotated the valves are moved and the ports uncovered, a straight way passage
communicates from port to port the valves and frame fill up the intervening space
excepting only the port mentioned. The covering valves are held against the face
by springs direct acting or operating as follows:-
To avoid the difficulty of direct springs which are liable to lose their strength
with heat we arrange at each end of the covering valves a pair of toggle levers the
toggle joint being central with the valve, and the outer ends of the levers press
against the ends of the covering valves so that when central spindles are forced
from outside the valve against the toggle joints, the covering valves are forced
against their faces simultaneously by a spring which acts upon the central spindles,
but outside the valve and beyond the reach of the heat. We prevent the loss of
pressure through the holes for the spindles by packing glands of the usual kind.
We rotate or oscillate the valve by a spindle and lever in the manner well known
as applied to Corliss valves in steam engines, and we pack the spindle and operate
the lever in any known manner from the valve or side shaft of the engine.
By this device we provide a valve which allows a free straight passage between
high pressure and low pressure cylinders and also presents surfaces capable of
resisting pressure from either cylinder. When the compression and explosion is to
occur in the high pressure cylinder the valve is so arranged as to position that the
port in it towards the high pressure cylinder may be slightly open while the other
port leading to the low pressure cylinder is completely closed and the half of the
valve covering it is pressed against the cylinder surface by the pressure and so it is
kept pressure tight. Like the Corliss valve our new valve is arranged to be held

page_text: agamist its face by the pressure to be retained and this advantage we obtain both
for pressure from H.P. to L.P. cylinders and pressure from L.P. to H.P. cylinders
by our divided circular valve.
In carrying the invention into effect in compound engines we prefer to compress
in the high pressure cylinder to a higher pressure than usual but we do not ignite
the mixture at that pressure. We prefer to ignite the mixture when the piston has
travelled forward somewhat and reduced the pressure.
By the late ignition the exploded charge retains a higher terminal heat, and we
release the charge before the usual period of exhausting when the high pressure
piston is slowing down at the end of its stroke and it passes through the valve
described to the low pressure cylinder.
We prevent the loss of temperature and pressure at this period by compressing
air or the products of the previous explosion into the end of the low pressure
cylinder and the passages leading thereto until the pressure equals or thereabout
the terminal pressure in the high pressure cylinder. The valve referred to being
thus nearly in equilibrium. The low pressure piston at the moment of admission
from the high pressure cylinder has passed the centre and travelled a little distance
on its working stroke and at the same time the high pressure piston is completing
its working stroke, and whilst the low pressure piston is travelling with great
rapidity the high pressure piston is passing its centre and remaining comparatively
stationary. We thus expand the charge in the most rapid and effectual manner
and lose the minimum of heat to the cylinder walls. The heated charge under this
arrangement can be expanded through both cylinders almost in the same time as in
the present system it expands in one cylinder. We cover the ends of the piston of
the low pressure cylinder and the passages leading to the high pressure cylinder
with asbestos paint or other non-conductor. With this system of compression and
release we may use any other valve than the one described and with double or
single acting gas engines.
To prevent danger to the low pressure cylinder and to admit of lighter
proportions being used, we have relief safety valves to allow of the escape of any
dangerous over pressure. When running light and cutting out we hold open the
exhaust valve of the low pressure cylinder to prevent the compression at the same
time the gas lever is inoperative.
To prevent ignition by leakage past the timing valve which controls the ignition
tube we arrange in connection with the ignition tube and in addition to a timing
valve of ordinary construction, a secondary valve which may be very small; the
said secondary valve opens an aperture leading to the ignition tube at a position
between the said ignition tube and the timing valve. The secondary valve is held
open while the timing valve is closed and so any gases which pass the timing valve
by leakage are discharged into the atmosphere and do not cause the tube to ignite
the mixture within the cylinder. The secondary valve is preferably placed parallel
with the main timing valve and operated from it by a suitable bar. The bar is so
moved that it first closes the secondary valve by aid of a strong spring and on its
further travel a stop is touched or a hollow nipple comes into contact with the end
of the timing valve spindle. The timing valve is then opened while the secondary
valve is held firmly closed by the spring. When the timing valve is closed again
by the reverse movement and a spring, the strong spring closing the secondary
valve, is released and a lighter spring opens it to allow leakage to escape.
In this manner we completely prevent ignitions in the cylinder due to leakage to
the igniter tube.
In the valve herein before described as forming the first part of this invention
nickel springs are preferred to steel.
In starting we measure into the cylinder an exact quantity of gas by measuring
with a small gasometer. We then force the compressed air until the mixture
reaches the incandescent portion of the tube. To attain this end we add at the
outer end of the incandescent tube a small receiver separated therefrom by a cock;
when the cock is closed the tube is in normal working condition but when the cock

page_text: is opened as in starting a lower pressure of the explosive mixture within the
cylinder enables it to reach the incandescent portion of the tube, and the larger
body of explosive mixture in the receiver discharges more rapidly and ignites the
charge with greater certainty.
We sometimes in starting explode a charge in the low pressure cylinder
separately or in conjunction with the high pressure cylinder the larger area giving
a greater impetus towards getting the engine "under way."
In the said straight way valve also we sometimes arrange an end movement as
well as a reciprocating movement in order to ensure even wear of the face and to
avoid cutting.
We arrange a suitable compound engine in which to carry out the invention by
combining two "Otto" cycle high pressure cylinders with a central low pressure
cylinder, each "Otto" cylinder being timed to exhaust alternately into the central
expansion cylinder and the valves arranged to permit of this.
The second part of the invention, that is the secondary relief valve applied to the
timing valve will be found useful in engines of ordinary construction and also the
starting arrangement.
Our low pressure cylinder we preferably arrange with its crank at or about right
angles to the cranks of the high pressure cylinder.
Dated this 26th day of September 1892.
MARKS & CLERK,
13, Temple Street, Birmingham, Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in Compound Gas Engines, in part applicable to
other Gas Engines.
We, JOHN WILLIAM HARTLEY, of 2 Henrietta Street, Kilmarnock, Engineer,
and JOHN KERR, Engineer, a member of the Firm of Dick, Kerr and Company,
Britannia Engineering Works, Kilmarnock, both in County of Ayr, 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 :-
Our invention relates to improvements in the arrangements of compound gas
engines, and its object is to provide means of igniting and passing hot gases from
the high pressure to the low pressure cylinder with a minimum loss of heat, and
also to provide a valve arrangement communicating with an igniter tube of such
nature as to render premature ignitions from leakage an impossibility. We ignite
the compressed explosive mixture after the crank has passed the centre instead of
on the centre as is usual, and at the same time we compress air or the products of
combustion in the second cylinder and passages leading thereto.
Referring to the five accompanying sheets of drawings-
Figure 1 is a transverse section of a compound engine showing our new valve
as arranged to pass hot gases from the high pressure to the low pressure cylinder.
Figure 2 is a separate plan of the valve drawn to a larger scale.
Figure 3 is a transverse section of the valve in its closed position on the same
scale as Figure 2.
Figure 4 is a similar section of a modified valve.
Figure 5 is a section of our valve showing one mode of pressing it up to its
working face by external springs.
Figure 6 is a similar section to Figure 5 showing another mode of pressing it up
to its working face by external springs.
Figure 7 is a similar section to Figure 5 showing the whole valve on a smaller
scale with springs in position.
Figure 8 is a section similar to Figure 6 showing both ends of the valve.

page_text: Figure 9 is a plan part in section of a three-cylinder compound engine to which
our valves are applied.
Figure 10 is a section illustrating our new safety ignition valve.
Figure 11 is a diagram showing the relative positions of high pressure and low
pressure piston and cranks at the moment of the release of the gases from the high
pressure cylinder and the admission to the low pressure cylinder.
Figure 12 is an indicator diagram from the high pressure cylinder of an engine
constructed in accordance with our invention, showing the required points of
ignition and release.
Figure 13 is an indicator diagram obtained from our low pressure cylinder.
In carrying the first part of our invention into effect, we construct a valve
suitable for connecting between the high and low pressure cylinders in the following
manner-
We arrange between the high pressure and low pressure cylinders A and B a
valve casing A2 (Figure 1) containing a bored out cylinder and we connect the
interior of the said cylinder with both high and low pressure cylinders A and B by
straight ports A' B' of ample area, which ports we make as short as possible.
Within the bored out valve cylinder we place a circular valve C C' which valve
fits the said cylinder accurately and has a straight port C2 right through it opening
to the straight ports A' B' in the high and low pressure cylinders.
This circular valve consists of a valve frame D and two covering valves as shown
more clearly at Figures 2 and 3.
The covering valves C C (Figures 2 and 3) close the opposite port openings
respectively A B', and when the frame D is rotated the valves are moved and the
ports covered or uncovered; a straight way passage communicates from port to
port; the valves and frame fill up the intervening space excepting only the port
inentioned. The covering valves C C are held against the faces by direct acting
springs as shown in plan at C³ C Figure 2. The springs C3 C4 are placed between
the covering valves CC) and so thrust out the said valves against the valve cylinder
surfaces.
Direct acting springs, however, are liable to lose their strength by the action
of heat, and to avoid this difficulty we arrange at each end of the covering valves
toggle levers of which the toggle joints are central with the valve and the outer
ends of the said levers press against the ends of the covering valves; central
spindles are placed in position to operate the toggle joints, so that the covering
valves are forced against their faces simultaneously by the action of the said
central spindles.
To operate the central spindles a spring is arranged outside the valve and beyond
the influence of the heat. We prevent loss of pressure through the holes for the
spindles by packing glands of the usual kind.
We rotate or oscillate the valve by a suitably packed spindle and a lever in the
manner well known as applied to Corliss valves in steam engines.
We operate the lever in any known manner from the crank shaft or side shaft of
the engine.
In Figure 2, D' is the valve spindle for oscillating the valve and D2 is a lever,
keyed or otherwise attached to the said spindle. The lever D2 is actuated by the
link D3 (Figure 1) which link is in turn operated from the rotating valve shaft E
by the cam F and the lever G.
In the valve shown in Figure 3 we use two covering valves or plates C C₁, but
we sometimes dispense with one of the covering, valves and use one only as shown
at C Figure 4, where the valve frame D is made to fill up the valve cylinder and
is cut through by the port C². In this case the port Bi is covered by the valve
plate C and pressure from the port A forces it to its face. a is an oil pipe which
supplies oil to suitable oil grooves.
An arrangement of toggle links for forcing the cover or plate valves to their
faces by means of external springs and a central spindle is shown at Figure 5
which is a longitudinal section of one end of a valve. C Care the cover plate

page_text: valves and D is one end of the valve frame with its spindle D'. Through the
centre of the spindle D' there passes the spindle H which acts on the ends of a
pair of toggle links K K': the inner ends of the said links abut and work upon a
shoulder on the spindle H and the outer ends abut the internal projections b b¹ on
the cover plate valves. The spindle H when forced inwards then causes the outer
ends of the toggle links K K' to press out the cover plate valves C C. Similar
arrangements are made at both ends of the valves to force out the plates.
When one cover valve only is used as C Figure 4 only one toggle link K is used
at each end of the valve, and the spindle H is backed up by the valve casing to
enable it to take the side thrust. Figure 7 shows two such valves in section and
elevation. The single toggle links K K operated at each end by the spindles H H
thrust out the cover plate C and hold it tightly against its working face. The
spindles H H are pressed inwards by the spiral springs S1 S2 on the rod S. The
springs S1 S2 press on the ends of levers R R and so force in the spindles H H.
The spindles H H in the elevation shown in the same figure are similarly acted
on by levers R2 R³.
The rod R is reciprocated from any suitable part of the engine and it acts on
the end of the lever R' which lever is pivoted to the rod S at R. The lever R² is
also pivoted to S at R. By this arrangement the levers R' and R' are both
reciprocated by the action of the rod R and an end motion is given to the valve
which prevents cutting and keeps the faces in good condition.
The springs S and S2 are made of sufficient length and strength to constantly
maintain a necessary pressure on the covering or plate valves notwithstanding the
reciprocation of the rods R* and S.
Instead of using toggle links K K, a bell crank lever or bell crank levers may
be used. One end of a valve operated by a bell crank lever arrangement is shown
at Figure 6. The single cover valve C is here pressed home by the bell crank
lever I which lever is forced to its work by the spindle H. A section of the
complete valve using bell crank levers I I¹ is shown at Figure 8.
In the section of the valves C C¹ shown in Figure 9 the double toggle arrangement
is shown.
By this device of an oscillating valve we provide a valve which allows a free
straight passage between high pressure and low pressure cylinders and also presents
surfaces capable of resisting pressure from either cylinder.
When the compression and explosion is to occur in the high pressure cylinder
the valve is so arranged as to position that the port in it towards the high pressure
cylinder may be slightly open while the other port leading to the low pressure
cylinder is completely closed and the half of the valve covering it is pressed against
the cylinder surface by the pressure and so it is kept pressure tight. This is clearly
seen at Figure 3, where the port C2 is shown as slightly open to the high pressure
port A' so that the pressure from A' may bear upon the back of the cover valve C
and keep it up to its face and thus effectually close the port B'. Like the Corliss
valve, our new valve is arranged to be held against its face by the pressure to be
retained, and this advantage we obtain both for pressure from high pressure to
low pressure cylinders and pressure from low pressure to high pressure cylinders
by our divided circular valve.
We thoroughly water jacket these valves and we extend the covering valves to
give sufficient contact with the water jacket. This extension also permits us to
lubricate effectively.
Water jacket spaces are lettered T at Figures 4, 7, 8 and 9.
The fulcrum 12 of the bell crank II (Figure 6) may be fixed to the valve
frame D as shown in which case only one cover plate valve C is used, or it may be
fixed to a second cover plate C exactly as shown at Figure 6, in which case one
bell crank at each end of the valve operates two cover valves or plates.
In carrying the invention into effect in compound engines we prefer to compress
in the high pressure cylinder to a higher pressure than usual, but we do not ignite the
mixture at that pressure. We ignite the mixture when the piston has travelled forward

page_text: somewhat and reduced the pressure. By the late ignition the exploded charge retains
a higher terminal heat, and we release the charge before the usual period of exhausting
when the high pressure piston is slowing down at the end of its stroke, and the hot
gases then pass through the valve described to the low pressure cylinder. We
further prevent the loss of temperature and pressure at this period by compressing
air or the products of the previous explosion into the end of the low pressure
cylinder and the passages leading thereto until the pressure equals or thereabout
the terminal pressure in the high pressure cylinder. The air when air is used
we introduce to the low pressure cylinder and passages either by an independent
pump, or when the low pressure cylinder does not expand a hot charge at every
stroke we utilize the idle stroke or strokes to draw or force in air to supply the low
pressure cylinder. The oscillating valve is thus brought nearly into equilibrium,
before it is opened to allow free communication between the cylinders. The
crank of the low pressure piston at the moment of beginning admission from
the high pressure cylinder is so set that it has passed the centre and travelled
a little distance on its working stroke and at the same time the high pressure
piston is completing its working stroke, and whilst the low pressure piston is
travelling with great rapidity the high pressure piston is passing its out centre
and remaining comparatively stationary. We thus expand the charge in the
most rapid and effective manner and lose the minimum of heat to the cylinder
walls. The heated charge under this arrangement can be expanded through both
cylinders almost in the same time as in the present system it expands in one
cylinder.
With this system of ignition, compression and release we may use any other
valve than the one described and with double or single-acting gas engines. To
prevent danger to the low pressure cylinder and to admit of lighter proportions
being used, we have relief safety valves to allow of the escape of any dangerous
over pressure. When running light and cutting out we sometimes hold open the
exhaust valve of the low pressure cylinder to prevent the compression at the
same time the gas lever is inoperative.
In order to produce a compound gas engine in which the minimum loss of heat
occurs during expansion we find it essential as bereinbefore described to ignite
the compressed inflammable gases in the high pressure cylinder at a point of the
working stroke after the crank has crossed the centre, that is, at a short distance
on the working stroke of the high pressure piston, and we also find it necessary
to release the hot gases from the said cylinder considerably before the end of
the piston stroke.
By so arranging the ignition of the gases and their release we secure the
minimum loss of heat in the high pressure cylinder and leave a considerable
proportion of power to be utilized in the low pressure cylinder. To secure the
largest possible utilization of the power we provide a very free passage between
the two cylinders controlled by a straight way valve as described, and by com-
pressing air or other gases in the clearances of the low pressure cylinder we
avoid the loss by fall of pressure during admission.
Figure 11 is a diagram showing the relative positions of the high pressure and
low pressure cranks and pistons at the moment of release from the high pressure
cylinder and admission to the low pressure cylinder. W is the high pressure crank
and X the low pressure crank.
The cranks rotate in the direction of the arrow.
The stroke of both pistons is indicated by the space between the lines Y Y.
The high and low pressure connecting rods are respectively indicated at W₁ X'
and the positions of the respective pistons are indicated at W and X'. The
cranks are arranged at right angles.
From this diagram it will be seen that the low pressure piston has travelled a
short distance on its working stroke, and the high pressure piston has still to travel
about one quarter of the stroke at the moment when communication is made
between the two cylinders.

page_text: Figure 12 is an indicator diagram such as we obtain in the high pressure cylinder
showing the desired position for igniting the mixture and the best position for release.
The action of the ignition valve is timed to produce the somewhat late explosion
line g h, and the straight way valve is opened to cause the release at the point i
about one quarter before the end of the high pressure stroke. ef is the atmosphere
line.
Figure 13 is an indicator diagram from the low pressure cylinder in which m n is
the atmosphere line, k the line of compression of the air or other gases in the low
pressure cylinder, and in the line of expansion of the gases in the low pressure
cylinder.
In carrying out the second part of our invention which is intended to prevent
ignition by leakage past the timing valve which controls the ignition tube, we
arrange (see Figure 10) in connection with the ignition tube and in addition to a
timing valve L of ordinary construction, a secondary valve M which may be very
small; the said secondary valve opens an aperture leading to the ignition tube O at
a position between the said ignition tube O and the timing valve L. The secondary
valve M is held open while the timing valve L is closed and so any gases which
pass the said timing valve by leakage are discharged into the atmosphere and do
not cause the tube to ignite the mixture within the cylinder. The secondary valve M
is preferably placed parallel with the main timing valve L and operated from it by
a suitable bar Q. The bar Q is so moved that it first closes the secondary valve M
by aid of a strong spring M2 acting against a weaker spring M³ and on its
further travel a stop is touched or the bottom of a hollow nipple P comes into
contact with the end of a timing valve spindle L'. The timing valve L is then
opened while the secondary valve M is held firmly closed by the compression of the
spring M². When the timing valve L is closed again by the reverse movement of
the operating lever and a spring L³, the strong spring M' closing the secondary
valve M is released, and a lighter spring M³ opens it to allow leakage to escape. In
this manner we completely prevent ignitions in the cylinder due to leakage to the
igniter tube.
The bar Qis attached to the hollow nipple P and the said nipple P is operated
by a lever not shown. The pin L2 passed through the timing valve spindle L'
moves in a slot Q' in the bar Qin such a manner that the spring L³ thrusts out the
bar Qand when the pin L2 arrives at the bottom of the slot Q' then the valve L is
also closed by the spring L³. M' is the spindle of the secondary valve.
We arrange a suitable compound engine in which to carry out the invention by
combining two "Otto" cycle high pressure cylinders with a central low pressure
cylinder, each "Otto" cylinder being timed to exhaust alternately into the
central expansion cylinder and the valves arranged to permit of this. Figure 9
is a plan part in section of such an engine in which A A are two high
pressure cylinders which alternately expand into the low pressure cylinder B
which is placed between them. The hot gases expand through valves C C as
shown in section and in the double acting engine shown four such valves are
used. In this engine both ends of all three cylinders are utilized and as
two impulses are given for every two revolutions in each of the high pressure
cylinders, and two impulses are given for every revolution in the low pressure
cylinder, it follows that in the whole engine working at full power we obtain four
power impulses for every revolution, two impulses per revolution due to the high
pressure cylinders and two due to the low pressure cylinder. The valve shafts E E'
operate suitable valves of known construction.
The second part of the invention, that is the secondary relief valve applied to the
timing valve will be found useful in engines of ordinary construction.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
1. In a compound gas or like engine the method of working which consists in

page_text: delaying the ignition until the crank of the high-pressure cylinder has passed the
dead centre, releasing the products of combustion early from the high-pressure
cylinder, and at the same time providing a very direct and short passage between
the two cylinders for the products of combustion, substantially as herein described
for the purpose specified.
2. In a compound gas or like engine the method of working which consists in
delaying the ignition until the crank of the high-pressure cylinder has passed the
dead centre, releasing the products of combustion early from the high-pressure
cylinder, compressing in the low-pressure cylinder to such a degree that there is
substantially no sudden drop of pressure of the products of combustion in the high-
pressure cylinder at the moment of release, and at the same time providing a very
direct and short passage between the two cylinders for the products of combustion,
substantially as herein described, for the purpose specified.
3. A compound gas or like engine having a very direct and short passage between
the high and low pressure cylinders for the products of combustion as herein
described, and in which the products of combustion or atmospheric air or other gas
are or is compressed in the low-pressure cylinder during the return stroke of the
piston to such a degree that there is substantially no sudden drop of pressure of the
products of combustion in the high-pressure cylinder at the moment of release,
substantially as described.
4. A compound gas or like engine having a very direct and short passage between
the high and low-pressure cylinders for the products of combustion said passage
being controlled by a valve comprising a frame and a covering valve or covering
valves which is or are pressed against the working face by springs and by the
pressure of the gases in the said passage, substantially as described.
5. Forcing the said covering valve or valves to the working face by means of
external springs operating through central spindles and toggles or links, substantially
as described.
6. The apparatus constructed substantially as described with reference to
Figure 7 of the drawings, and operating as, and for the purpose, specified.
7. The combination, with a timing valve for a gas engine, of a relief valve which
opens automatically when the timing valve is shut, and closes when the timing
valve is opened for the purpose specified.
8. The combined timing and relief valve, constructed substantially as described
with reference to Figure 10 of the drawings, and operating as, and for the purpose,
specified.
9. A compound gas engine having our improvements incorporated therein as
described with reference to the accompanying drawings.
Dated this 27th day of July 1893.
MARKS & CLERK,
13, Temple Street, Birmingham, Agents for the Applicants.