IMPROVEMENTS IN GAS MOTOR ENGINES
Year: 1877

page_text: LETTERS PATENT to Nicolaus Auguste Otto, of The Gas Motoren Fabrik Doutz,
at Deutz, in the German Empire, Engineer, and Francis William Crossley, of
Manchester, in England, Engineer, for the Invention of "IMPROVEMENTS IN
GAS MOTOR ENGINES."
Sealed the 28th March 1877, and dated the 5th February 1877.
PROVISIONAL SPECIFICATION left by the said Nicolaus Auguste Otto and
Francis William Crossley at the Office of the Commissioners of Patents on the
5th February 1877.
NICOLAUS AUGUSTE OTTO, of The Gas Motoren Fabrik Deutz, at Deutz, in the
German Empire, Engineer, and FRANCIS WILLIAM CROSSLEY, of Manchester, in
England, Engineer. "IMPROVEMENTS IN GAS MOTOR ENGINES."
This Invention relates to improvements in gas motor engines of the kind
described in the Specification of a Patent No. 2081, granted on the 17th May, 1876,
to C. D. Abel, for an Invention coinmunicated from abroad by N. A. Otto.
In engines constructed according to the said Specification a governor is applied
to move longitudinally along a rotating shaft, a cam, whereby the gas supply slide
is moved, and from this arrangement it sometimes results that should the engine be
brought to a standstill by over work, or otherwise, the gas slide may remain open,
allowing an escape of gas. To obviate this defect a light load is put on the governor,
regulating it, so that at the normal speed the cam is brought into position to work
the gas slide, but should the speed either increase considerably or diminish the cam
is moved to the one side or the other, permitting the gas supply orifice in either
case to be closed by the spring on its slide.
Besides the light load above mentioned for the governor there is also provided an
additional weight which usually rests on a collar or other support on the governor
spindle, and is only brought to bear on the governor balls when they become
extended by a speed exceeding the normal rate. By this means the cam is held
beneath the gas slide roller when the engine works at a very slow speed without
making a corresponding reduction of the speed necessary by which it is moved in
the opposite direction.
According to another arrangement in place of the gas slide described in the

page_text: before-mentioned Specification we provide in a chamber on the gas supply an
ordinary disc valve connected to the one end of a lover, the other end of which
carries a roller, actuated by the before-mentioned sliding cam, so as to open the valve
against the pressure of a spring.
In starting the engine by turning it round by hand it may sometimes be necessary
to bring the cam into position to work the gas slide notwithstanding the slow speed
at which the governor spindle is thus made to revolve; there is therefore provided
for the governor lever a spring catch or a removeable weight sufficient to retain the.
cain in working position until the engine acquires a somewhat greater speed, where-
upon the catch is withdrawn or the weight is removed, allowing the governor to act
as above described.
In starting the engine by hand, as above mentioned, the work of compressing the
charge before ignition, as described in the before-mentioned Specification, is some-
what troublesome, particularly in large sized engines. In order to lighten this
work we form the cam that works the escape valve on a sleeve that can slide on its
shaft, and on this sleeve we form a second cam in such a position that when the
sleeve is shifted before starting the engine, so as to cause this cam on the rotation
of its shaft to act on the lever of the escape valve, the latter will be opened thereby
for a certain time, while the piston is partly compressing the charge, and this in
being thus allowed to escapo partly, will consequently only require a moderate
amount of power to effect its compression to the end of its stroke. The engine
being started the sleevo is shifted back into its normal position, in which the
additional cam does not act upon the lever of the escape valve.
The before-mentioned cam on the sleeve moved by the governor for working the
gas valve is made narrow, so that instead of a graduated supply of gas it either
gives a full charge or none. Thus the speed is regulated by varying the number of
explosions, which may either be successive or at intervals, as the work demanded of
the engine requires, while the speed of the engine inay nevertheless remain approxi-
mately the same.
In order that the working charge in the cylinder may be of the same composition
when the first of a series of explosions takes place after an interruption of the series,
as above described, there is provided on the caru sleeve worked by the governor a
second cam connected to the exhaust valve of the cylinder, holling it open during
that portion of the stroke of the piston when the charge is being drawn into the
cylinder, so that the hot products just expelled are in great measure drawn back a
into the cylinder instead of a fresh charge of colder air, the passage of which in the
slide is considerably smaller than that of the exhaust valve. By thus retaining
partly the hot products of combustion in the cylinder, or restoring a large portion
of them to the cylinder, there is secured economy in the expenditure of gas required
for working an engine when at less than full power.
As the cylinder of the engine is open at one end the packing of the piston can be
regulated from without by adopting the following construction of piston:-The
piston is made in two parts, the one which is the trunk or body, and the other
which is the junk ring, secured to the former by a central bolt provided with a
lock nut. This central bolt being fixed to the junk ring is provided with a square
or polygonal end, so that on slacking the lock nut a wrench can be applied to the
bolt to turn the junk ring round relatively to the trunk of the piston.
Between the junk ring and trunk there is an outer split spring or packing ring
coned on the inside, and within it another ring coned' externally to fit the former.
The latter ring is made with two or more inclines on its edge, bearing against corre- 5
sponding inclines formed on the trunk or on the junk ring; and it has a stud, by
which in the former caso it is turned round along with the junk ring, or by which
in the latter case it is held stationary when the junk ring is turned. In either caso
the turning of this junk ring by means of a wrench applied to the central bolt has
the effect of moving the inner ring longitudinally by the action of the inclines, and 5
this movement has the effect of expanding the outer packing ring, or allowing it to
contract, according to the direction in which the bolt is turned. On one edge of

page_text: the outer packing ring is formed a groove or annular recess which is fitted with a
split spring ring similar to that commonly known as Ramsbottom's packing rings,
but springing inwards instead of outwards. This ring is placed in a groove in the
packing ring, breaking joint therewith, and pressing it inwards, its clasticity causing
it to bear on the bottom of the annular recess so as to prevent leakage past it to
the split of the packing ring.
Another improvement relates to the construction of the engine slide, and tho
arrangement of passages in connection therewith, for effecting the ignition of the
charge in the cylinder after compression. The cover of the main slide has a small
chimney formed on it partly below, and partly within which a small gas jet is kopt
continually burning. The slide has a forked passage formed in it leading to an
opening on its inner face through which the ignition of the charge is effected when
the slide is brought into the proper position. Before the slide is brought into this
position the one branch of the said passage is made to communicate with a hole in
the cover leading to the said chimnoy, while the other branch communicates with
another hole in the cover leading to the atmosphere. Another small passage in the
valve establishes a communication between the said forked passage and a groove
in the slide cover, into which a small gas pipe opens, so that during a certain portion
of the stroke of tho valvo combustible gas will pass into the forked passage, where
it will mix with air entering the lower branch. On the forked passage being made
to communicate with the flame its charge is ignited, and on the further motion of
the slide, the communication being cut off between the forked passage and the gas
jet, it is brought in communication with the inlet port of the cylinder so as to fire
the charge. Just before this takes place however the before-mentioned small
passage in the slide through which the forked passage is charged is made to com-
imunicate with a small passage lending to the interior of the cylinder, so that a
portion of the compressed combustible charge in the cylinder will enter the forked
passage, pushing before it the gas contained in the small passage in the slide,
maintaining the combustion in the forked passage and raising the pressure of the
gases therein to that existing in the cylinder, so that when the forked passage com-
municates with the port of the cylinder the inflamed charge of the former will
readily enter and ignite the charge of the latter.
The last-mentioned small passages may also conveniently be formed as chases or
grooves, formed respectively in the slide face and in the cylinder face, the latter
leading from the inlet port some distance back in the direction of the travel of the
slide. The channel by which the forked passage is charged with combustible gas
may advantageously have an enlargement or cavity formed upon it to contain a
larger volume of gas.
In order to prevent or reduce the noise occasioned by the air rushing through the
supply valve we introduce a pipe which leads the air from any locality to the gas
engine, and at an intermediate point of the pipe we provide a chamber or closed
vessel communicating at one point with the supply pipe, and at another point with
a pipe leading to the engine slide.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Nicolaus August Otto and Francis William Crossley in the Great
Seal Patent Office on the 3rd August 1877.
NICOLAUS AUGUST OTTO, of The Gas Motoren Fabrik Deutz, at Deutz, in the .
German Empire, Engineer, and FRANCIS WILLIAM CROSSLEY, of Manchester, in
England, Engineer. "IMPROVEMENTS IN GAS MOTOR ENGINES."
This Invention relates to improvements in gas motor engines of the kind
described in the Specification of a Patent No. 2081, granted on the 17th May,
1876, to C. D. Abel, for an Invention communicated from abroad by N. A. Otto,
.

page_text: In engines constructed according to the said Specification a governor is applied to
move longitudinally along a rotating shaft a cain, whereby the gas supply slide is
moved, and from this arrangement it sometimes results that should the engine be
brought to a standstill by over work or otherwise, the gas slide may remain open,
allowing an escape of gas. To obviate this defect a light load is put on the governor,
regulating it, so that at the normal speed the camn is brought into position to work
the gas slide, but should the speed either increase considerably or diminish, the cam
is moved to the one side or the other, permitting the gas supply orifice in either case
to be closed by the spring on its slide.
Besides the light load above mentioned for the governor, there is also provided
an additional weight which usually rests on a collar or other support on the
governor spindle, and is only brought to bear on the governor balls when they
become extended by a speed exceeding the normal rate. By this means the cam is
held beneath the gas slide roller when the engine works at a very slow speed, and
yet is not moved from under it unless the normal or much greater speed is
exceeded.
According to another arrangement, in place of the gas slide described in the
before-mentioned Specification, we provide in a chamber on the gas supply an
ordinary disc valve connected to the one end of a lever, the other end of which
carries a roller actuated by the before-mentioned sliding cam, so as to open the
valve against the pressure of a spring.
In starting the engine by turning it round by hand it may sometimes be necessary
to bring the cam into position to work the gas slide notwithstanding the slow speed
at which the governor spindle is thus made to revolve; there is therefore provided
for the governor lever a spring catch or a removeable weight sufficient to retain the
cam in working position until the engine acquires a somewhat greater speed, where-
upon the catch is withdrawn or the weight is removed, allowing the governor to act
as above described.
In starting the engine by hand, as above mentioned, the work of compressing the
charge before ignition as described in the before-mentioned Specification is some-
what troublesome, particularly in large sized engines. In order to lighten this
work we form the cam that works the escape valve on a sleeve that can slide on its
shaft, and on this sleeve we formn a second cam in such a position that when the
sleeve is shifted before starting the engine, so as to cause this cam on the rotation
of its shaft to act on the lever of the escape valve, the latter will be opened thereby
for a certain time while the piston is commencing the compressing stroke, and the
charge in being thus allowed to escape partly, will consequently only require a
moderate amount of power to effect its compression to the end of the stroke. The
engine being started the sleeve is shifted back into its normal position in which
the additional cam does not act upon the lever of the escape valve.
4
The before-mentioned cam on the sleeve, moved by the governor, for working the
gas valve is made narrow, so that instead of a graduated supply of gas it either
gives a full charge or none. Thus the speed is regulated by varying the number of
explosions, which may either be successive or at intervals, as the work demanded of
the engine requires, while the speed of the engine may nevertheless remain 4
approximately the same.
In order that the working charge of the cylinder may be of the same composition
when the first of a series of explosions takes place after an interruption of the series
by the governor, as above described, there is provided on the cam sleeve worked by
the governor a second cam which only comes into operation when the normal speed 5
is exceeded, and which is connected to the exhaust valve of the cylinder, thus
holding it open during that portion of the stroke of the piston when the charge is
being drawn into the cylinder, so that the hot products just expelled are in great
measure drawn back into the cylinder instead of a fresh charge of colder air, the
passage for which in the slide is considerably smaller than that of the exhaust 5
valve. By thus retaining partly the hot products of combustion in the cylinder, or

page_text: restoring a large portion of them to the cylinder, thero is secured economy in the
expenditure of gas required for working an engine when at less than full power.
Fig. 1 of the accompanying Drawings shows a part side elevation of a gas motor
engine shewing our before described improvements; Fig. 2 shews an end view
partly in section, and Fig. 3 shews a cross section through the escape valve of the
cylinder.
b is the way shaft carrying the crank for actuating the slide to the cylinder and
the cams for actuating the gas valve and the escape valve for the products of com-
bustion, and driven from the engine shaft in the same manner as described in Abel's
before-mentioned Specification. The cam a for actuating the valve g that admits
the combustible gas to the engine is carried by the sleeve q revolving with 0 but
capable of sliding, on the shaft b. It is only slightly wider than the roller d on the
lever h, actuating the gas valve, so that if slid by the action of the governor
sufficiently far to the one side or the other of the roller d to be clear of it, as shewn
at Fig. 1, the cam will fail to actuate the lever h, and the gas valve g will remain
closed by the action of the spring i. The governor balls are carried by a light
sleeve c sliding on a revolving rod f and driven by gearing from the shaft b, as
shown, the rectilineal motion of the sleeve c being imparted to the cam sleeve q by
the lever c. When the engine is stopping the sleeve c in dropping with the
governor balls moves the sleeve q so as to bring the cam a into the position shown
in Fig. 1, so that in whatever point of its revolution it may be when the engine
comes to a standstill, the cam cannot hold the gas valve open. When the engine is
started the governor balls raise the sleeve c, so as to move the cam a from the
position shewn at Fig. 1, to a position immediately underneath the roller d, so that
it effects the opening of the gas valve at the proper time for admitting the com-
bustible charge into the cylinder.
When the engine has attained more than its normal speed the sleeve c is raised to
such a height as to lift an additional lond e off a shoulder on the rod f, so that the
governor is then loaded to a greater extent than when starting, and thus, although
the cam is brought under the roller & when the engine is working at a slow speed, it
is not moved to the right from under it unless the normal or much greater speed is
exceeded. When this latter takes place the cam is, by the rising of the governor,
brought clear of the roller & to the right-hand side, and the gas valve remains
closed, and consequently no combustible charge is introduced into the cylinder until
the speed of the engine is again sufficiently reduced so as to bring the cam under
the roller. As on first starting the engine it is necessary to effect the opening of
the gas valve by the cam even before the governor is capable of bringing the latter
into position; this is effected by means of a tumbler weight hung loose on a pin
on the lever c'. The sleeve is lifted somewhat by hand, and the weight is moved
so as to bring one of its corners to rest upon the top of the governor stand, thus
causing it to hold the governor up, and consequently to bring the cam under the
roller until the engine is started. When the engine has attained such a speed that
the governor rises beyond the position in which it is held by k, the latter being
lifted off its support, will swing back into the position shewn at Fig. 1, in which
there is sufficient space between its under side and the governor stand to allow the
governor to drop, so as to bring the cam into the position shewn when the engine
stops. The combustible gas passes from the valve chamber g¹ to the slide through
the passage g², Fig. 2.
The can, Fig. 3, for actuating the valve p for the escape of the products of
combustion is mounted on a sleeve that can be slid by hand on the shaft b. On
the sleeve is a second cam m only partly as wide as 7, and in such a position relative
thereto that when the sleeve is slid into the dotted position at Fig. 1 the cam m
will act on the roller of the lever o, so as to open the escape valve p for a short
time during that stroke of the piston by which the gaseous charge is compressed
before firing. When the engine is working, the sleeve l is kept in the position
shewn in Fig. 1, in which the cam m cannot act on the lever o, but when the engine
is being started by hand the sleeve is moved into the dotted position, whereby

page_text: when the piston commences its compressing stroke, the escape valve is opened for a
short time, so as to allow a portion of the charge to escape, and thus render the
work of effecting the compression of the charge by hand less heavy.
On the sleeve 9 of the gas cam a is a ring r which, when the sleeve with its cam
is moved to the right of the roller & by the governor, owing to the engine running
above the normal speed, as before explained, is brought under a roller & carried by
the lever o, and thus, in acting on the lever, holds the escape valve p open all the
time the explosive charges are discontinued, so as to allow the products of combustion
to be drawn back into the cylinder at the outstrokes of the piston, for the purposes
'before explained.
As the cylinder of the engine is open at one end the packing of the piston can be
regulated from without by adopting the following construction of piston. The
piston is made in two principal parts; the one, which is the trunk or body, and the
other, which is the junk ring, secured to the former by a central bolt provided with
a lock nut. This central bolt being fixed to the junk ring is provided with a square
or polygonal end, so that on slacking the nut a wrench can be applied to the bolt,
to turn the junk ring round relatively to the trunk of the piston. Between the
junk ring and trunk there is an outer split ring or packing ring coned on the inside,
and within it another ring coned externally to fit the former. The latter ring is
mado with two or more inclines on its edge bearing against corresponding inclines
formed on the trunk or on the junk ring, and it has a stud by which, in the former
case, it is turned round along with the junk ring, or by which, in the latter case, it
is held stationary when the junk ring is turned; in either case the turning of the
junk ring by means of a wrench applied to the central bolt has the effect of moving.
the inner ring longitudinally by the action of the inclines, and this movement has
the effect of expanding the outer packing ring or allowing it to contract, according
to the direction in which the bolt is turned. On one edge of the outer packing ring
is formed a groove or annular recess, which is fitted with a split spring ring similar
to that commonly known as Ramsbottom's packing ring, but springing inwards
instead of outwards. This ring is placed in a groove in the packing ring, breaking
joint therewith and pressing it inwards, its clasticity causing it to bear on the
bottom of the annular recess, so as to prevent leakage past it to the split of the
packing ring.
5
Figs. 4 to 7 of the Drawings shew the above-described improved construction of
piston; Fig. 4 shews a sectional side view of the piston; Fig. 5 shews a side view
of the same at right angles to Fig. 4; Fig. 6 shews a plan and side view of the end
of the body t; and Fig. 7 shews a plan and side view of the junk ring u. The junk
ring is connected to the body t by a rod v, the end w of which is formed to fit
the socket of a wrench, whereby it can be turned so as to turn the junk ring
relative to the body. The split packing ring a is coned on its inner surface, and
within it is a second ring y, with coned outer surface, fitting against x, as shewn.
This ring has inclines fitting against corresponding inclines formed on the body t
and a pin or stud u' on the junk ring u fits into a notch in the ring y, so that as u
is turned it also turns y, and owing to the inclines this is moved longitudinally,
thereby pressing the ring outwards against the cylinder surface. The packing
ring has a groove formed in its lower end, into which is fitted a split spring
ringspringing inwards and breaking joint with the split of the packing ring,
for the purpose above described. The rod v has a nut v screwed on it which is
screwed up tight when the ring has been adjusted, as described, and loosened again
when further adjustment is required. The front part of the piston is formed, as
shewn, so that access can be gained to the rod from the open end of the cylinder,
the connecting rod being attached to the eye t¹.
2
Another improvement relates to the construction of the engine slide, and the
arrangement of passages in connection therewith for effecting the ignition of the
charge in the cylinder after compression. The cover of the main slide has a small
chimney formed on it, partly below and partly within which a small gas jet is
kept continually burning. The slide has a forked passage formed in it leading to

page_text: an opening on its inner face, through which the ignition of the charge is effected
when the slide is brought into proper position. Before the slide is brought into
this position the one branch of the said passage is made to communicate with a
hole in the cover leading to the said chimney, while the othor branch cominunicates
with another hole in the cover leading to the atmosphere. Another small passago.
in the valve establishes a communication between the said forked passage and a,
groove in the slide cover into which a small gas pipe opens, so that during a certain
portion of the stroke of the valve combustible gas will pass into the forked passage,
whero it will mix with air entering the lower branch. On the forked passage being
inade to communicate with the flame its charge is ignited, and on the further motion
of the slide, the communication being cut off between the forked passage and the
gas jet, it is brought in communication with the inlet port of the cylinder, so as to
fire the charge. Just before this takes place, however, the before-mentioned small
passage in the slide through which the forked passage is charged is made to com-
municate with a small passage leading to the interior of the cylinder, so that a
portion of the compressed combustible charge in the cylinder will enter the forked
passage, pushing before it the gas contained in the small passage in the slide, main-
taining the combustion in the forked passage, and raising the pressure of the gases
therein to that of the charge in the cylinder, so that when the forked passage com-
municates with the port of the cylinder the inflamed charge of the former will
readily enter and ignite the charge of the latter. The last-mentioned small passagos
may also conveniently be formed as chases or grooves formed respectively in the
slide face and in the cylinder face, the latter leading from the inlet port some
distance back in the direction of the travel of the slide. The channel by which
the forked passage is charged with combustible gas inay advantageously have an
enlargement or cavity formed upon it to contain a larger volume of gas.
Figs. 8 to 14 of the Drawings shew the above-described improved construction of
slide and parts in connection therewith. Fig. 8 shews a front view of the slide and
slide cover; Fig. 9 shews a section on line X, X, Fig. 8; Fig. 10 shews a section on line
Y, Y, Fig. 8, the slide being supposed to have moved a little, so as to bring the
forked passage in full section in each case; Fig. 11 shews a section on line Z, Z,
Fig. 8; Fig. 12 shews a section on line W, W, Fig. 10; Figs. 13 and 14 shew
respectively the inner face of the slido cover and of the slide detached. The slide A
has formed in it the chamber B, which, when the slide is in the position shewn in
Fig. 9, communicates both with the opening C in the slide cover D and with the
opening E leading into the chimney F on the slide cover in which is the igniting
flame G. Above the chamber B is a small passage H communicating, firstly, with a
groove I in the slide cover into which combustible gas is admitted through the
pipe J, secondly with the chamber B, and it has also an opening in the inner face
of the slide, which, when the slide is in the position shewn in Fig. 12, communi-
cates with the small passage K in the cylinder above the inlet port L of the latter,
the passage H having a lateral notch, as shewn at Fig. 12, and being arranged in
such a position relatively to the chamber B, as slicwn at Fig. 14, that it establishes
a communication between the chamber B and the interior of the cylinder through
the passage K just before B communicates directly with the port L.. The slide
being in the position shewn at Fig. 9 air enters B through C, and gas enters it
through H, and the mixed charge is ignited through the hole E by the flame G.
The slide then moves towards the position shewn at Fig. 10, but just before B
communicates with L the passage H is put in communication with the passage K
by means of the notch, as shown at Fig. 12, whereby the pressure of the com-
pressed charge in the cylinder can be transmitted to the chamber B, and render the
pressure therein equal to that in the cylinder before it opens to the latter, so that
on such communication being established the flame from the chamber will readily
enter the cylinder.
It will be seen that when the communication between H and K is established,
that between H and the gas passage I and pipe J is cut off, so that the compressed
gases cannot escape up the gas pipe.
'

page_text: The passage H may be formed either as at Fig. 10 or it may have an enlarge-
ment as at H, Fig. 9, so as to contain rather more gas, when the communication
with J is cut off.
M is the passage in the slide for establishing a communication between the port L
and the air passage O and port P to the gas passage for the introduction of the
combustible charge into the cylinder, both the passages O and P being in this case
formed in the cylinder end; N are the perforations through which the gas enters
M in small jets, so as to mix intimately with the air passing in.
In order to prevent or reduce the noise occasioned by the air rushing through
the supply valve we introduce a pipe which leads the air from any locality to the
gas engine, and at an intermediate point of the pipe we provide a chamber or closed
vessel cominunicating at one point with the supply pipe, and at another with the
pipe leading to the engine slido.
Fig. 15 shews a vertical section of this arrangement. The pipe Q leading from
the air passage O in the engine cylinder, as shewn at Fig. 11, opens into the side of
the closed vessel R, from the top of which a pipe S leads to the locality from which
the air supply for the engine is to be taken.
Having thus described the nature of our Invention, and in what manner the
same is to be performed, we claim,―
First. Establishing an equilibrium of pressure between the compressed charge in
the cylinder and the igniting charge in the slide chamber before such chamber com-
municates directly with the cylinder port, substantially as and for the purposes
herein described.
Second. Arranging the passage in the slide through which the combustible gas for
the igniting charge is introduced into the slide chamber to communicate with a passage
leading into the cylinder before the slide chamber communicates directly with the
latter, in order to effect an equilibrium of pressure between the compressed charge
in the cylinder and the igniting charge, substantially as herein described.
Third. The arrangement of the cam and governor for working the gas supply
valve or slide, whereby the cam is moved entirely to one side of the valve or slide
lever by the governor when the engine runs too fast, so as not to effect the opening
of the valve or slide until the speed is reduced, substantially as and for the purpose
herein described.
Fourth. The arrangement of the cam and governor for working the gas supply
valve or slide, whereby the cam is moved entirely to one side of the valve or slide
lever by the governor when the engine stops, so that the cam cannot theu hold the
gas valve or slide open, substantially as herein described.
Fifth. In combination with the arrangement of cain and governor for the gas
supply valve set forth in the preceding claim the provision of a supplemental load
on the governor, so arranged that it only acts on the governor when the engine is
working at or above the normal speed, substantially as described.
Sixth. In combination with the arrangement of cam and governor to the gas
supply valve set forth in the fourth claim the provision of means whereby the cam
is temporarily held in position for acting on the gas valve on first starting the
engine, substantially as herein described.
Seventh. The provision of means for allowing a portion of the gascous charge to
escape from the cylinder when compressing by hand on first starting the engine,
substantially as and for the purposes herein described.
Eighth. Providing on the sleeve of the cam that operates the gas valve a second
cam or disc, so arranged relatively to the escape valve lever that on the engine
running above the normal speed the said cam or disc holds the escape valve open,
while the piston is performing its outstroke, substantially as and for the purposes
herein set forth.
Ninth. Expanding the packing ring of the piston by means of an inner coned
ring, so arranged in combination with inclines formed either on the trunk of the
piston or on a rotatable junk ring that on rotating the junk ring the said inner ring
is caused to move longitudinally, substantially as herçin described.

page_text: Tenth. In combination with the split packing ring of the piston the use of a
second split ring fitting in a groove in the first-named ring, and springing
inwards, so as to press tight against the bottom of the groove, substantially as
herein described.
.
Eleventh. The use in combination with the air supply pipe to a gas engine of
a closed receptacle or chamber connected to the supply pipe leading from the
locality from which the air supply is taken, and to a separate pipe leading to the
air inlet of the gas engine, substantially as and for the purpose herein described.
In witness whereof, I, the said Francis William Crossley, have hereunto set
my hand and seal, this Thirtieth day of July, in the year of our Lord
One thousand eight hundred and seventy-seven.