MPROVEMENTS IN GAS ENGINES
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by the said Henry Clay Bull at the
Office of the Commissioners of Patents on the 29th October 1883.
HENRY CLAY BULL, of Liverpool, in the County of Lancaster LMPROVEMENTS
IN GAS ENGINES
My Invention relates to that class of gas engines in which an effective stroke is
obtained for every revolution of the crank in a single cylinder in which work
a primary and a secondary piston, the motive agent employed being the heat
resulting from the explosion, or combustion of a mixture of combustible gas, or
vapour with air, the gas used being ordinary coal, or oil gas, or the gases resulting
from the partial combustion of coal in a gas producer, or any other suitable gas, or
vapour.
The improvements which constitute my Invention consist essentially of the
following features and parts, namely I arrange a primary and secondary piston to
work within a cylinder according to the following cycle of operation. Presuming
the primary piston to be near the outer end of its stroke and having just opened
an exhaust port in the cylinder, the secondary piston is caused by the positive
action of a cam and an arrangement of levers to follow up the primary piston and
expel all gases which exist between the two pistons and at the same time, and by
the same action (a gas valve and air inlet being opened) the secondary piston draws
into the cylinder a charge of air and gas making a combustible mixture. By the
time the secondary piston has reached the outer end of its stroke, namely having
arrived at the commencement of the exhaust port, the primary piston will have
returned covering the exhaust port and on its further instroke pushes back the
secondary piston and compresses the charge of combustible fluid which has been
drawn in by the secondary piston. When the primary piston has nearly reached
the end of its instroke, the cam and lever arrangement again comes into operation
and causes the secondary piston to have a further instroke namely to the end of
the cylinder, which forces the compressed charge of air and gas through valves in
: TDi 11

page_text: the secondary piston, so that such charge comes between the two pistons and is
there ignited and an effective stroke is imparted to the primary piston by the heat
resulting from the combustion of the compressed air and gas, thus completing the
cycle of operation. The gas inlet valve which is situated in combination with and
within the air inlet trunk is so arranged that it is opened immediately upon the
commencement of the outward stroke of the secondary piston and is closed slightly
before the end of such outward stroke. Thus the air and gas inlet passages to the
cylinder are left filled with air only, thereby limiting the combustion of the
inflammable fluid to the space between the two pistons and so preventing any
explosion taking place in proximity to the air and gas. inlet valve behind the
secondary piston, or in its valve passages. Then on the outward stroke of the
secondary piston, the air which fills the passages aforesaid will be drawn into
the cylinder in front of the combustible charge.
The beforegoing being the cycle of operation of a gas engine constructed under
the improvements which constitute part of the improved features of my Invention
I will now proceed to describe an engine, the parts of which are constructed
according to my Invention and suitable for carrying out the before described cycle
of operation.
The
The cylinder consists of two concentric vessels, the outer one of which is cast, or
formed with internal projecting studs and is provided with an air and gas inlet
port and with an exhaust port and with provisions for supplying the water jacket
and pistons hereafter spoken of with water. The inner vessel is a steel tube, which
is expanded on to the projecting studs of the outer vessel and forms the working
cylinder. The annular stud filled space between the two cylinders constitutes the
water jacket. The inner vessel is provided with openings which correspond with
the air and gas inlet port, and with the exhaust port of the outer vessel. The
outer end of the cylinder is open and the inner end is provided with a water
jacketted cover. The top of the cylinder is provided with a circulating pump, the
function of which is to create a forced circulation through the pistons as hereafter
described and through and round the water jacket of the cylinder and cover.
primary piston is of hollow construction and is cast, or formed in one piece with a
cross head and guide block being connected thereto by a hollow connecting piece at
the top having two water ways and by a connecting piece at the bottom. This
hollow connecting piece serves as water ways from the circulating pump on the
cylinder to supply the water space of the primary piston and also the hollow
secondary piston hereafter described with water. The periphery of the piston has
a circumferential slot to allow the water in the piston to come into contact with
the inner surface of the cylinder. The centre of the piston is provided with a boss
through which there is a hole, which forms a way for the rod of the secondary
piston, packing rings being provided for the rod of the secondary piston to work in,
and a circumferential slot which allows the water in the piston to come in contact
with the rod of the secondary piston. The cross head takes up in hollow
construction from the top connecting piece before spoken of and is connected to
two hollow plungers of return nature which work into the circulating pump before
spoken of on the cylinder. One of the plungers is provided with a valve which
opens from the plunger to one water way of the piston. The water is forced to the
pistons through one way (and returns through the other way) to the water jacket
of the cylinder and cover. The cross head of the primary piston is connected to
the crank of the engine by a connecting rod in the usual way and the frame of the
engine is provided with a guide in which works the cross head guide block. The
secondary piston is also of hollow construction and is provided with valves which
allow communication between the outer end of the cylinder and the space between
the two pistons to allow the compressed charge of gas and air to pass through as
described in the cycle of operation before set forth. The secondary piston has a
circumferential slot similar to the primary piston to allow water contact from the
piston to the internal surface of the cylinder. Two tubes are also provided which
lead from the water space of the secondary piston into the water conducting

page_text: ways of the primary piston. The rod of the secondary piston is of hollow
construction, and its interior communicates with the water space of the secondary
piston. The rod of the secondary piston passing through the packed way:
provided in the primary piston connects with a bell crank lever and a rocking
lever which latter is operated by a cam on the crank shaft and gives the requisite
positive motion to the secondary piston to ensure its correct movement in the
cycle of operation before set forth. To enable the engine to be reversed the rocking
lever is worked from a weigh shaft, which is provided with two levers, one of
which takes into a cam set for running the engine one way round and the other
takes into a cam which is set for running the engine in the reverse direction.
These levers are brought into gear by a clutch arrangement worked froin a lever
which also sets the ignition valve hereafter spoken of. The cams above described
are formed, or set in discs, which form the engine crank. The reversing lever is
connected to the valve spindle, which works the ignition valve, the reversing gear
being an ordinary rocking link worked by an eccentric and rod from the engine
shaft. The gas and air inlet port is provided with a trunk, near the top of which
is located an ordinary lift valve, through which the air and gas pass into the
cylinder. Beneath this valve and in the trunk is placed a hollow cylindrical gas
valve provided with a casing which is placed laterally in and forms part of the
trunk. The gas is admitted into the valve and passes through a slot in its upper
side into the trunk where it comingles with air and is drawn into the cylinder.
The valve is opened and closed for each stroke of the engine by a cam on a
secondary shaft and is worked by bevel gear from the main shaft. The engine is
governed by an ordinary spring governor, which is driven from bevel gearing on
the secondary shaft. The governor operates a hollow shaft, placed over the
secondary shaft and causes the gas valve to be opened or remain closed as the
speed of the engine varies. by means of a block which is dropped between, or is
withdrawn from between a slide, which is operated by the cam before mentioned,
and a second slide, which is connected to the lever of the gas valve spindle, so
that when the block lies between the two slides, the cam operating the first slide
opens the gas valve, the closing of the valve being effected by a spring or its
equivalent when the block is withdrawn from between the two slides by the
governor, owing to an increased speed of the engine, the gas valve will not be
opened as the cam merely moves the first slide up to the gas valve slide, and hence
no movement is given to it, and the valve will remain closed until the speed of
the engine becomes sufficiently reduced for the governor to drop the block between
the slides again and so re-operates the gas valve.
33
For the ignition of the combustible charge of gas and air, I employ a slide
valve having two chambers. One chamber serves as a reservoir, the other being
a flame pocket. The valve is worked from an eccentric on the main shaft, as
before described and works on a face on the side of the cylinder in which is
placed a communicating passage extending from the igniting valve to the interior
of the cylinder. The valve is kept up to its seat by a cover, which is retained by
bolts and springs, the outside of the cover being provided with a chimney lined
with porcelain and has a "Bunsen flame burning in it, which serves as the
"master" flame, the porcelain lining being provided to establish and maintain a
high temperature in the chimney. Communication between the slide valve and
the chimney is by a port in the inner face of the valve cover. The slide valve
flame pocket is also porcelain lined and has two ports, one on its side next the
cylinder and the other in the side next the valve cover, thus forming a through
communication between the valve cover and the cylinder by way of the flame
pocket. A small passage is provided in the valve and connects the flame pocket
with the reservoir above spoken of-The valve reservoir chamber also being in
communication with the interior of the cylinder through a port in its side next
the cylinder. The ignition is effected as follows: presume the engine to have
drawn into the cylinder a combustible charge of gas and air and the piston is
compressing the charge on its return stroke, the reservoir port in the slide valve

page_text: is caused to pass over the cylinder ignition passage and will take in a compressed
charge of gas and air from the cylinders charge. Communication between the
reservoir and the cylinder will cease on the piston arriving at the end of its
inward and compressing stroke. The thus compressed charge of gas and air in the
reservoir will then issue into the flame pocket, the valve travelling forward the.
communication between the reservoir and the cylinder will be cut off and instantly
the flame pocket will be open to the master flame. Thus the gas and air issuing
from the reservoir into the flame pocket will be ignited and the valve passing
rapidly forward will cut off the flame pocket from the master flame and will
instantly communicate with the cylinder and ignite the compressed combustible
charge, which lies between the primary and secondary pistons. During the
travelling of the ignition valvo from the cutting off of the communication of the
reservoir with the cylinder to the igniting of the charge the primary piston will
have travelled about one inch of its outward stroke thus reducing the pressure in
the cylinder below the pressure in the pocket, so that when the ignition port to
the cylinder is open, the excessive pressure in the pocket sends the flame into the
cylinder.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Henry Clay Bull in the Patent Office on the 26th April 1884.
HENRY CLAY BULL, of Liverpool, in the County of Lancaster IMPROVEMENTS
IN GAS ENGINES"
My Invention relates to that class of gas engines in which an effective stroke is
obtained for every revolution of the crank in a single cylinder in which work a
primary and a secondary piston, the motive agent employed being the heat resulting
from the explosion, or combustion of a mixture of combustible gas or vapour with
air, the gas used being ordinary coal, or oil gas, or the gases resulting from the
partial combustion of coal in a gas producer, or any other suitable gas, or vapour.
The Improvements which constitute my Invention consist essentially of the
following features and parts, namely a primary and secondary piston is arranged
to work within a cylinder according to the following cycle of operation. Presuming
the primary piston to be near the outer end of its stroke and having just opened
an exhaust port in the cylinder, the secondary piston is caused by the positive
action of a cam and an arrangement of levers to follow up the primary piston and
expel all gases which exist, between the two pistons and at the same time and by
the same action (a gas valve and air inlet being opened) the secondary piston draws
into the cylinder a charge of air and gas making a combustible mixture. By the
time the secondary piston has reached the outer end of its stroke, namely having
arrived at the commencement of the exhaust port, the primary piston will have
returned covering the exhaust port and on its further instroke pushes back the
secondary piston and compresses the charge of combustible fluid, which has been
drawn in by the secondary piston. When the primary piston has nearly reached
the end of its instroke the cam and lever arrangement again comes into operation
and causes the secondary piston to have a further instroke, namely to the end of
the cylinder which forces the compressed charge of air and gas through valves in
the secondary piston, so that such charge comes between the two pistons' and is.
there ignited and an effective stroke is imparted to the primary piston by the heat
resulting from the combustion of the compressed air and gas, thus completing the
cycle of operation. The gas inlet valve which is situated in combination with and
within the air inlet trunk is so arranged that it is opened immediately upon the
commencement of the outward stroke of the secondary piston and is closed slightly
before the end of such outward stroke. Thus the air and gas inlet passages to the
cylinder are left filled with air only, thereby limiting the combustion of the
inflammable fluid to the space between the two pistons and so preventing aný
explosion taking place in proximity to the air and gas inlet valve behind the
secondary piston, or in its valve passages. Then on the outward stroke of the
secondary piston, the air which fills the passages aforesaid, will be drawn into
the cylinder in front of the combustible charge
The following is a description of a gas engine constructed according to this
Invention in such full, clear and distinct terms as to enable any one skilled in the
art to which this Invention belongs to put the same into practice, reference being
had to the annexed sheets of Drawings which are marked with figures and letters
of reference corresponding to those used in this Specification like letters and
figures being used to denote the same, or corresponding parts throughout the
VATIONS VIAWA
-

page_text: Figure 1 is a side elevation of a gas engine constructed according to my
Invention
Figure 1 is a plan of Figure 1
Figure 1 is a back end view of Figure 1.
Figure 1º is a front end view of Figure 1.
Figure 2 is a plan of Figure 1 shown partly in section.
Figure 3 is a cross section through A A Figure 1.
Figure 4 is a sectional elevation of the engine.
Figure 5 is a cross section through B. B. Figure 1.
Figure 6 is a sectional elevation of the pistons.
Figure 7 is a cross section through C. C. Figure 6.
Figure 8 is an outside view of Figure 7.
Figure 9 is a cross section through D. D. Figure 6.
Figure 10 is an outside view of Figure 9.
c.
Figure 11 is a section through the gas and air inlet valves..
Figure 12 is a section through E. E. Figure 11.
Figure 13 is a cross section through F. F. Figure 12
Figure 14 is an elevation of the governing and operating mechanism for the gas
inlet valve.
Figure 15 is an end view of Figure 14.
Figure 16 is a plan of Figure 15.
Figure 17 is a sectional plan of the ignition valve.
Figure 18 is a cross section of the ignition valve.
Figure 19 is a section through G. G. Figure 17.
b
On reference it will be seen that A is the cylinder which is shown constructed
with a lining a, which is expanded onto the studs a'. The space between the
cylinder A and its liner a forms a water jacket. a³ is the gas and air inlet port
and a is the exhaust port. A' is the cylinder cover, which is also water lined.
B is the primary piston, which is of hollow construction and is formed in one piece
with the crosshead guide block B' being connected by the double waterway B³.
C is a circulating pump of which 6 b' are the plungers 6 being the supply plunger
and being the return plunger. The plunger b is supplied with suction and
delivery valves. The function of the pump C is to circulate water to the several
parts of the engine to which water is supplied. The piston B has a groove round
its periphery to allow contact of the water in the piston with the lining a of the
cylinder. D is the secondary piston which is of hollow construction and is
provided with a groove on its periphery to allow contact of the water with the
lining a from the piston D. Water is supplied and returned through the tubes d
which work through the piston B and waterways B¹. The piston D is provided
with non return valves d' to allow the combustible mixture to pass into the space
between the pistons D B. D' is the piston rod of the piston D and works through
the piston B. E is the disc crank. F is the connecting rod, which is attached to
the crosshead B' as shown. The discs E are provided with grooves E¹, which give
to the piston D its necessary motion through the levers G G G². The grooves E'
are formed in the respective discs EE in reverse, so that one disc has its groove set
to work the piston D when the engine is running in one direction and the other
disc has its groove set to work the piston D when the engine is running in the
reverse direction and the levers G are thrown in and out of gear with the lever G¹
as the case requires by the clutch G³, the clutch G³ being worked by the bell crank
lever g and rod gl
H is the trunk of the gas and air inlet port a' in which is placed the gas
admission valve J, a space is provided around this valve for the passage of the air,
and J¹ is a non return valve through which the air and gas pass into the port a*
and cylinder A. The valve J is opened and closed for each stroke of the engine by
the cam K on the secondary shaft L, which is driven by bevel gear L' from the
engine shaft. The engine is governed by an ordinary spring governor M which is

page_text: driven from bevel gearing M¹ on the secondary shaft L. The governor M operates
a hollow shaft L' placed over the secondary shaft L and causes the gas valve J to
be opened, or remain closed as the speed of the engine varies, by means of a block Z
which is dropped between, or is withdrawn from between a slide n which is
operated by the cam K and a second slide n' which is connected to the lever j of
the spindle of the gas valve, so that when the block lies between the slides n and
n the cam K by operating the slide n opens the gas valve J, the closing being
effected by the spring when the block is withdrawn from between the slides n
and n by the governor Mowing to increased speed of the engine the gas valve J will
not be opened as the cam K merely moves the slide n and no movement is given to
the slide n' and the valve J will remain closed until the speed of the engine becomes
sufficiently reduced for the governor M to drop the block / between the slides n and
n' again and so re-operate the gas valve J.
For the ignition of the combustible charge of gas and air there is employed a slide
valve P having two chambers P and 9. The chamber p serves as a reservoir and
the chamber g as a flame pocket. The valve P is worked from an eccentric N on
the main shaft and works on a face on the side of the cylinder A in which is placed
a communicating passage r extending from the valve P to the interior of the
cylinder. R is the valve cover which is provided with a chimney R' lined with
porcelain and having a Bunsen flame burning therein, which serves as the master
Hame, the porcelain lining being provided to maintain a high temperature in the
chimney, is the communicating port between the master flame and the flame
pocket q. The latter is also porcelain lined and has two ports, which form a through
communication between the ports and by way of the flame pocket q. A small
passage pl connects the flame pocket g with the reservoir p, the latter being also
in communication with the interior of the cylinder through the port p³.
The
is
The ignition is effected as follows: presume the engine to have drawn into the
cylinder A a combustible charge of gas and air and the piston B is compressing the
charge, the port p³ passes over the port and admits a charge of compressed gas
and air into the reservoir p. Communication between the reservoir p and the port r
is shut off on the piston B arriving at the end of its compressing stroke.
compressed charge in the reservoir p issues through the passage p₁ into the flame
pocket q, the valve P travelling forward; communication through the ports p² and r
is cut off and instantly the flame pocket g is opened through the port rl to the
master flame. Thus the charge issuing from the reservoir p into the pocket
ignited and the valve P passing rapidly forward cuts off the flame pocket q from
the master flame and instantly communicates with the cylinder A through the port r
and ignites the combustible charge which lies between the pistons D and B.
During the travelling of the valve P from the cutting off of the communication of
the reservoir p with the port r to the igniting of the charge, the piston B will have
travelled about one inch of its outward stroke, thus reducing the pressure in the
cylinder A below the pressure in the pocket q, so that when the port r is opened,
the excess of pressure in the pocket q sends the flame into the cylinder A. through
the port T.
The reversing of the engine is effected by the lever g³ which operates the rod g¹
before described and the ignition valve P through the rod S. The rod S works in
the fixed link T, the latter being operated by the eccentric N and eccentric rod N¹
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed, what I claim is
First The combination in the cylinder A of the primary power piston B and the
secondary piston D, which latter is worked by the cam E and whereby the com-
bustible charge is drawn into the cylinder A and the products of combustion are
expelled and the combustible charge is compressed and forced between itself and the
piston B for ignition as herein set forth.
Second. The arrangement of the water ways B' piston B, piston D pipes d and
cylinder water jacket with the pump C, whereby the water is forced through the

page_text: pistons B and D and through the cylinder water jacket and lubricates the interior
of the cylinder as herein set forth.
Third The combination of the valve J, lever j, spring ³, slides n' and n, block i,
cam K, rod L³ and governor M, whereby gas is admitted to the cylinder A and such
admission regulated as herein set forth.
:
Fourth The arrangement of the reservoir p, passages p' and p' flame pocket g of
the valve P, in combination with the ports and whereby the reservoir P is
supplied with compressed combustible mixture and feeds the flame pocket 9 and
ignites the combustible mixture in the cylinder A.
Fifth The combination of the eccentric N, link T rod S levers G, clutch G³, lever g,
rod g and lever. g with the valve P and D, whereby the direction of the motion
of the engine is reversed.
In Witness whereof, I the said Henry Clay Bull have hereunto set my hand and
seal this Twenty fourth day of April, in the year of our Lord one thousand eight
hundred and eighty-four.