IMPROVE- MENTS IN GAS MOTOR ENGINES
Year: 1881

page_text: LETTERS PATENT to Charles Denton Abel, of No. 28, Southampton Buildings,
· Chancery Lane, in the County of Middlesex, for an Invention of "IMPROVE-
MENTS IN GAS MOTOR ENGINES." A communication from abroad by
Nicolaus August Otto, of the Gas Motoren Fabrik Deutz, 'of Deutz, in the
German Empire.
PROVISIONAL SPECIFICATION left by the said Charles Denton Abel at the
Office of the Commissioners of Patents on the 5th January 1881.
CHARLES DENTON ABEL, of No. 28, Southampton Buildings, Chancery Lane,
in the County of Middlesex. "IMPROVEMENTS IN GAS MOTOR ENGINES."
[A communication from abroad by Nicolaus August Otto, of the Gas Motoren
Fabrik Deutz, of Deutz, in the German Empire.].
In gas motor engines it is found very advantageous to ignite the combustible
gaseous charge while the piston is still at the dead centre before commencing the
working stroke, or when it has only moved slightly from that position. In the
construction of the gas motor engine, now generally known as the Otto silent
engine," and described in the Specification to Letters Patent, No. 2081, of 1876,
granted to me as a communication from the said N. A. Otto, a space was provided
in the cylinder beyond the piston when at the end of its in-stroke for containing
the combustible charge, whereby the engine was enabled to be worked in the
manner above mentioned, and the space thus formed remained charged with air or
products of combustion after the piston had performed its return stroke after the
working out stroke.
According to the present improvements the said space is still retained at the
end of the cylinder, but means are provided for removing the products of com-
bustion therefrom at the end of each return stroke of the piston after the working
outstroke, either by means of an auxiliary piston so arranged that when the
working piston performs its instroke the auxiliary piston advances into the said
space so as to expel its contents, while when the combustible charge is drawn in
and is being compressed the said space is left free by the auxiliary piston ; or,

page_text: according to another arrangement, the auxiliary piston is dispensed with, and the
working piston is made to perform strokes of variable length in such manner that
during the return stroke after the working out-stroke it advances to near the inner
end of the cylinder, so as to expel the whole of the products of combustion, while
at the end of the compressing instroke, when it is on the dead centre, the piston is
situated at some distance from the end of the cylinder so as to leave a space into
which the combustible charge is compressed.
According to another feature, described in the before mentioned Specification,
No. 2081, of 1876, the combustible charge for the engine was so formed that while
a portion of the charge at the point of ignition consisted of undiluted explosive
mixture which rendered ignition certain, the other portion of the charge consisted
of combustible gas more or less diluted with or dispersed among non combustible
or inert gases, whereby the combustion of the charge and consequent expansion of
the gas was made to take place gradually. This mode of forming the combustible
charge is also applicable with the above described modes of operating, by causing
air alone to be drawn in at the commencement, and afterwards a combustible
mixture of gas and air.
Various arrangements may be adopted for causing gas motor engines to operate
according to one or other of the above described methods. Thus according to one
arrangement for operating with an auxiliary piston this is situated in an extension
of the cylinder, in which it is pressed forward towards the working piston by a
spring, so that when the working piston is at end instroke for expelling the
products the two pistons are situated close together, the whole of the products
being thus expelled. The engine slide being in position for admitting first a
charge of air and then a charge of explosive mixture the working piston performs
its outstroke, drawing in the combustible charge in the manner above described,
after which it performs its compressing instroke. The strength of the spring acting
on the auxiliary piston is such that when the charge has been compressed to a
certain extent its pressure overbalances that of the spring, so that during the latter
part of the compressing stroke the auxiliary piston is forced backwards in the
extension of the cylinder, thus leaving the space within the latter free to receive
the compressed charge when the working piston arrives at the dead centre at the
end of its instroke. On the ignition of the compressed charge in the usual manner
the working piston performs its working outstroke, at, the end of which the escape
valve of the cylinder being opened by the action of a cam on a countershaft of the
engine the products of combustion escape as the piston performs its instroke,
while at the same time the auxiliary piston being relieved of the gaseous pressure
is moved forward by its spring so as to expel the whole of the products of com-
bustion, as first described.
.
According to another arrangement the auxiliary piston instead of moving in the
axial line of the working piston and cylinder works in a cylindrical chamber at a
right or other angle to the engine cylinder. The outer end of this chamber may
be closed, so that when the auxiliary piston is forced back into it the air behind
the piston will be compressed, and will assist the action of the spring. The weight
of the piston may also be brought in aid, if the cylindrical chamber is arranged in
a vertical position.
According to another arrangement the auxiliary piston is actuated by means of
a cam on a countershaft of the engine, so that it is intruded into the cylinder
extension when the products of combustion are being expelled, and is withdrawn
or forced back by the gaseous pressure towards the end of the compression stroke.
According to another arrangement, applicable to a machine with two working
cylinders, wherein the piston of the one cylinder is performing its compressing
stroke, while the other performs its expelling stroke; the two auxiliary pistons
are connected to opposite arms on a rocking shaft receiving motion, so that
while the one such piston is intruded into the cylinder extension during the
expelling stroke of its working piston, the other one is withdrawn during the
compressing stroke of its piston.

page_text: According to another arrangement the auxiliary piston is connected by a lever
and connecting rod to a crank or eccentric on a countershaft made to revolve at
half the speed of the engine shaft, the said crank or eccentric being so placed
relatively to the engine crank, that while the piston is performing its expelling
stroke the auxiliary piston is being intruded, while when the former is performing
its compressing stroke the latter is being withdrawn, a small portion of the
inward motion of the auxiliary piston being performed while the engine piston
commences its suction outstroke, and a small portion of its outward movement
while the engine piston commences its working stroke.
According to another arrangement the engine is provided with a separate pump
for compressing the combustible charge before it enters the engine cylinder, whose
piston performs a working stroke at every outstroke, and which is provided with
an auxiliary piston urged by a spring for expelling the whole of the products of
combustion, as first described. The pump is worked by a crank on the engine
shaft, so arranged relatively to the engine crank that the latter has a slight lead.
Thus the pump, which is provided with suitable suction and delivery valves, draws
in the combustible charge during its outstroke, and compresses it during about
three fourths of its instroke, and during the remaining fourth part forces it into the
engine cylinder, thereby forcing back the auxiliary piston against its spring.
During this time the engine piston is performing the last portion of its instroke,
and passing the dead centre will have just commenced its outstroke when the
compressed charge is fired, causing the piston to perform its outstroke. At the end
of this the escape valve is opened by a cam on a countershaft, and the products of
combustion escape while the engine piston performs its instroke, the auxiliary
piston being again intruded by its spring. During this time the pump piston has
performed its suction stroke, and is compressing its charge ready for forcing it into
the engine cylinder again. The opening and closing of the communications
between the pump and engine cylinder at the proper times, and the firing of the
charge is effected by a slide of usual construction worked from a crank on the
before mentioned countershaft.
In the above described arrangement, instead of actuating the auxiliary piston by
a spring it may be worked by a crank on the engine shaft, so placed that while the
engine piston performs its instroke, the auxiliary piston advances towards it, and it
is made to recede again while the compressed charge is being forced in by the pump,
and also during a portion of the time when the hot gases in the cylinder are
expanding.
According to another arrangement applicable where. the compression takes place
in the working cylinder itself, as in the first described arrangements, the auxiliary
piston is dispensed with, and the rod of the working piston, instead of being rigidly
connected to the crosshead of the engine as usual, is capable of sliding to and fro
through the same, the extent of such play being limited by stops. A spring is
provided whereby the piston is pressed inwards to the full entent of the play of its
rod during the expelling stroke, so as to cause the piston to advance close to the end
of the cylinder, while during the compressing stroke the pressure of the spring being
overcome by that of the compressed charge, the piston is forced back until the
inner stop on its rod bears against the cross head, and it is thus situated at some
distance from the cylinder end at end stroke. According to another modification
of this arrangement, the engine crank is connected to one end of a rocking lever on
which is pivotted a second lever, one end of which is connected to the piston rod;
while the other end is actuated either by a cam or by a crank on a countershaft
revolving at half the speed of the engine crank, so that during the expelling
instroke of the piston, it is caused by the second lever to advance to the end of
the cylinder, while during the compressing stroke, the said lever is moved
so as to prevent the piston from advancing beyond a certain distance from the
cylinder end..

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Charles Denton Abel in the Great Seal Patent Office on the
2nd July 1881.
CHARLES DENTON ABEL, of No. 28, Southampton Buildings, Chancery Lane,
in the County of Middlesex. "IMPROVEMENTS IN GAS MOTOR ENGINES."
A communication from abroad by Nicolaus August Otto, of the Gas Motoren
Fabrik Deutz, of Deutz, in the German Empire.
"
In gas motor engines it is found to be very advantageous to ignite the com-
bustible gaseous charge while the piston is still at the dead centre before
commencing the working stroke, or when it has only moved slightly from that
position. In the construction of the gas motor engine, now generally known as the
"Otto silent engine," and described in the Specification to Letters Patent, No. 2081,
of 1876, granted to me as a communication from the said N. A. Otto, a space was
provided in the cylinder beyond the piston when at the end of its instroke for
containing the combustible charge, whereby the engine was enabled to be worked
in the manner above mentioned, and the space thus formed remained charged with
air or products of combustion after the piston had performed its return stroke after
the working outstroke. These products of combustion do not materially interfere
with the combustion of the following charge if the gas employed is of a very
inflammable character, such as coal gas, but when gas of a less inflammable character
is used, such as carbonic oxide, it is of advantage to remove the said products more
or less completely.
According to the present improvements the before mentioned space is still
retained at the end of the cylinder, but means are provided for removing the
products of combustion, therefrom at the end of each return stroke of the piston
after the working outstroke, either by means of an auxiliary piston so arranged that
when the working piston performs its instroke the auxiliary piston advances into
the said space so as to expel its contents, while when the combustible charge is
drawn in and is being compressed, the said space is left free by the auxiliary
piston; or according to another arrangement the auxiliary piston is dispensed with,
and the working piston is made to perform strokes of variable length in such
manner that during the return stroke after the working outstroke it advances to
near the inner end of the cylinder, so as to expel the whole of the products of
combustion, while at the end of the compressing instroke when it is on the dead
centre, the piston is situated at some distance from the end of the cylinder so as to
leave a space, into which the combustible charge is compressed.
According to another feature, described in the before mentioned previous Patent,
the combustible charge for the engine was so formed that while a portion of the
charge at the point of ignition consisted of undiluted explosive mixture which
rendered ignition certain, the other portion of the charge consisted of combustible
gas more or less diluted with or dispersed among non-combustible or inert gases,
whereby the combustion of the charge and consequent expansion of the gases was
made to take place gradually. This mode of forming the combustible charge is also
applicable with the above described modes of operating by causing air alone to
be drawn in at the commencement, and afterwards a combustible mixture of gas
and air.
The accompanying Drawings shew various arrangements for causing gas engines
to operate according to one or other of the above described methods.
Figs. 1 to 7 shew various arrangements for operating with an auxiliary piston';
Fig. 1 shews a side elevation, and Fig. 1B a plan of one arrangement. c is the
engine cylinder, whose piston a is connected by a cross head running in guides

page_text: (not shewn on the Drawing), and connecting rod a¹ to the crank shaft w provided
with a fly wheel; c is the inlet port for the combustible charge of gas and air, the
admission of which is regulated by the slide c², connected by rod k to crank k¹³, on
shaft ², driven by gearing t from shaft w, the gearing being so proportioned that
the crank k makes one revolution for every two revolutions of w, so that the
slide makes one to and fro movement while the piston a makes two in and two
out strokes. By this means the piston a is during its first outstroke made to draw
in the combustible charge of gas and air, which charge it compresses by the following
in stroke, after which the charge is ignited, causing the piston to perform its
working outstroke, and on the following instroke the gaseous products of
combustion are expelled through the outlet valve v, the opening of which at every
alternate instroke is effected by a bell crank lever / connected by rod to a
lever g on shaft g, having a second lever g² with a roller in gear with a cam n on
shaft k².
The construction of the engine and its mode of operating are so far the same as
described in my before mentioned previous Patent.
The cylinder c has an extension c¹, in which is an auxiliary piston b, whose rod
passes thro' a guide d' on the open cover d, and which is pressed forward into the
position shewn in the Drawing by a spring b¹, the forward motion being limited
by the collar on the end of the rod.
The position of the parts shewn in the Drawing is assumed to be that in which
the piston a being at the end of its instroke and on the dead centre is about to
perform its outstroke to draw in the combustible charge of gas and air through, the
port, the slide c² being moved so as first to admit air alone, and then a mixture of
gas and air. On the completion of this stroke the slide c² having moved so as to
cut off the supply of gas and air, and the valve v being closed, the piston a in com-
mencing the return stroke compresses the gaseous charge, and when at a certain
point of the stroke the compression has attained such a degree as to overbalance
the pressure of the spring b₁ the piston 6 will be forced back in the extension cl, so
that by the time the piston a has again arrived at the position shewn in the
Drawing a space will exist between the two pistons in which will be contained
the compressed charge, the passage es being filled with undiluted explosive mixture
of gas and air, while the said space contains such mixture more or less diluteḍ
with the air first drawn in.
By the further movement of the slide the igniting flame therein fires the
compressed charge through the passage c³, and the resulting expansion of heated
gases causes the piston a to perform its working out stroke, imparting motion' to
the crank shaft w and its flywheel. When the piston has arrived at the end of
this outstroke the cam n effects the opening of the escape valve v, whereby the
gaseous products of combustion are allowed to escape as the piston a performs its
next instroke. At the same time the piston b being relieved of the gaseous
pressure in front of it is again moved forward from its backward position into the
position shewn on the Drawing, thereby filling up more or less entirely the space
behind the piston when this arrives at end instroke, so that the whole of the
products of combustion will be thus expelled, whereupon the above described cycle
of operations will be repeated.
.)
.
In the modified arrangement, shewn in the section of: the working cylinder at
Fig. 2, the auxiliary piston b, and the cylindrical extension c! are arranged at right
angles to the cylinder c, either. vertically or horizontally, instead of in line
therewith, the pressure of the conipressed charge in acting on the under face of
the piston b forcing it inwards against the action of the spring b' as before.
The end of the cylinder c¹ may be closed air tight, so that the imprisoned air
behind the piston in being compressed will assist the action of the spring, and if
the extension c¹ be vertical or inclined at any angle the weight of the piston b will
also be brought in aid of the spring.
1
It will be evident that in both the above described arrangements the auxiliary
piston might be urged by a weight instead of a spring..

page_text: In the arrangement shewn diagrammatically at Fig. 3-the auxiliary piston b is
connected by a lever q and rod p to a lever o bearing with a roller against a cam m
on shaft k¹, which is driven by gearing: t. from crank shaft w so as to revolve at
half the speed of the latter. By this arrangement the piston b.is forced back in
chamber c during the compression of the charge in the cylinder, while during the
second return stroke, when the products of combustion are expelled, the cam m
moves the levers o and q into the positions shewn-in dotted lines, whereby the
piston b is made to advance towards piston a so as to expel the whole of the
products of combustion, as before described.
Fig. 4 shews the Invention applied to a double cylinder engine, the pistons a, a¹,
being made to perform their in and out strokes simultaneously, but while the one
is performing its compressing instroke the other is making its expelling instroke.
The two auxiliary pistons b, b¹, are connected to a sway beam r so that as b is
being forced back during the compressing stroke of piston a it causes 6' to be
forced forward while piston a¹ is expelling the gases, and conversely.
In the arrangement shewn at Fig. 5 for a single cylinder engine the auxiliary
piston has a positive motion imparted to it both for its inward and outward move-
ment. For this purpose the shaft u driven by gearing at half the speed of the
crank shaft w has a crank or executric u¹ connected by rod u² and lever us to
piston b. The crank u¹ is so placed relatively to the crank of w that while the
piston a is performing its suction outstroke for drawing in the combustible charge
u is moving from position 1 to position 2, and consequently the piston 6 during
that time has a slight in and out movement, returning at the end of the stroke to
the same position which it occupied at the beginning, which is that shewn on the
Drawing, On the piston'a now performing its compressing instroke the crank u'
moves from 2 to 3, thereby withdrawing piston b so as to form the necessary space
behind a for containing the compressed charge. During the following working
outstroke of a the crank u moves from 3 to 4, maintaining piston b in its back-
ward position; and, lastly, during the expelling instroke of a crank u¹ moves from
4 to 1, causing b to move forward again into the position shewn, so as to expel
the whole of the products of combustion.
Figs. 6 and 6B shew the Invention as applied to a gas motor engine, in which
the combustible charge is compressed by a separate pump before entering the
engine cylinder, so that every stroke of the piston of the latter is a working
stroke.
x is the compressing pump having at y inlet and delivery valves arranged one
above the other in any suitable known manner, the cranks w³, w³, respectively of
the engine cylinder and the pump being situated at an angle 4-5 to each other, as
shewn at Fig. 6B. The action of the two cylinders is as follows:-The compressing
pump draws in a combustible charge during the half revolution from 4 to 1, Fig. 6B,
and compresses during the part 1-2 of the other half revolution, while during the
remaining portion from 2 to 4 the piston forces the compressed charge into
cylinder c through the slide 8, which is made for this purpose to open when w¹ is at
the point 2.
b
On entering the cylinder c the compressed charge forces back the auxiliary
piston 6 against the action of the spring b¹ so as to make room for the charge
behind the piston a, which at the time when the compressing pump is at end of its
instroke is just past its end instroke, w¹ being at point 5, it having moved from 4
to 5, while the pump crank w moved from 3 to 4.
tat
At this point the slide effects the ignition of the charge, this being the condition
of the engine shewn on the Drawing. The piston a is then caused to perform its
working stroke from 5 to 1 by the expansion of the heated gases, whereupon the
escape valve v is opened by the action of cam n, and the products of combustion
escape, while the piston is moving from 1 to 3. As the pressure in the cylinder
decreases during this time, the piston 6 is moved forward by its spring so as to meet
the piston a at point 3, and thus effect the expulsion of the whole of the products
of combustion. At this point the escape valve closes, and the pump piston being at

page_text: point 2 while the slide is opening the inlet port to cylinder c, a fresh compressed
charge is introduced and the above described cycle of movements is repeated.
The shaft being made by the gearing t to revolve with half the speed of the
engine shaft, the slide 8 also makes a single stroke for every double stroke of the
pistons, the ports and gas passages being in duplicate, as shewn, so that
the admission and ignition of the charge will be effected during both the in and the
outstroke of the slide...The cam nis also made double so as to effect the opening of
the escape, valve:v at each semi revolution.
Fig. 7 shews, an arrangement where the charge is also compressed by a separate
pump, not shewn on the. Drawing. In this case both the pistons a and b are con-
nected to the crank shaft, a being connected by rod L to crank K, and 6 by rod L¹
and lever L² to the smaller crank K. The cranks are at such an angle that during
one part of each revolution they cause the pistons to approach each other, and during
another part to recede from each other.
The inward movement of the piston b is made to take place while the piston a is
performing its instroke expelling the products of combustion, while during the first
part of the outward movement of 6 the charge is drawn in, and during the last
part this piston is acted upon by the expanding gases in a similar manner to
piston a.
Fig. 8 shews a construction of engine wherein the compression of the charge is
effected in the working cylinder, and which operates according to the second before
described method, according to which piston a is made to perform a stroke of
greater length for the expelling instroke than for the compressing instroke. For
this purpose the rod of the piston is not fixed to the cross head g, but is capable of
sliding through the same to an extent limited by the collars i, ¹, fixed thereon, a
spring tending to maintain the piston in the position with its collar ¹ bearing
against the cross head, so that when no counter pressure is opposed to the pressure
of the spring the piston will at the end of its instroke be situated close against the
cylinder bottom, as shewn, and it will thus be caused to expel the whole of the
products of combustion during its expelling instroke, the escape valve v being
open. But when during the compressing instroke the pressure of the compressed
gases rises above that of the spring of the piston will be forced back until the
collar i comes in contact with the cross head g, and thus when the piston has
arrived at the end of its stroke there will be a space between it and the bottom of
the cylinder containing the compressed charge. The cross head g works in guides,
not shewn, and is connected by rod a¹ to the crank shaft w. The slides is worked
by crank k on counter shaft k², driven at half the speed of w, as before.
It will be evident that with this arrangement the charge might also be compressed
by a separate pump before being introduced into the cylinder, the pressure of the
inflowing charge being made to force back the piston a against the action of its
spring.
Fig. 9 shews diagrammatically an arrangement in which the piston receives a
positive movement for effecting the alternate longer and shorter instrokes above
described.
For this purpose the crank w¹ of the engine shaft w is connected by rod W to one
end of a lever H, O, rocking on a fulcrum at O. On a pin J on this lever is
mounted a double ended lever M, M, whose one end is connected to the piston a
while its other end is connected by a rod N to a crank P on a shaft P¹, driven by
gearing from shaft wat half the speed of the latter.
The crank P operates relatively to the crank w' in the same manner as described
relatively to crank u', Fig. 5, so that while piston a is performing its suction out-
stroke crank P moves from 1 to 2, and during the following compressing instroke
it moves from 2 to 3, thereby moving the lever M, M, from the position shewn in
full lines into that shewn in dotted lines, M¹, so that the piston a will at the end.
of the compressing stroke be situated a distance away from the bottom of the
cylinder, thus leaving the requisite space for containing the compressed charge.
During the following working outstroke & expelling instroke the crank P in

page_text: moving from 3 to 1 will move lever M, M, back from the dotted into. the full
position, so that at end instroke piston a will be situated. close against the cylinder
bottom, as shewn.
Having thus described the nature of this Invention, and in what manner the
same is to be performed, as communicated to me by my foreign correspondent, I wish
it to be understood that I am aware that gas motor engines have been constructed
with two working pistons connected to opposite cranks, so that they are propelled
in opposite directions by the combustible charge, also that such engines have had
auxiliary pistons serving to draw in the combustible charge, and to be propelled
thereby towards the engine piston on firing, such an arrangement having been
described in the Specification to Brooman's Patent, dated 24 August 1863 (being
a communication from the said N. A. Otto), and I therefore do not claim such
arrangements, but
I claim in respect of a gas motor engine whose piston is connected to a crank on
the engine shaft, and in. which a space for containing the combustible charge exists
behind the piston when this is at the end of its stroke,-
First. The use of an auxiliary piston so arranged and operated as to be intruded
into the space behind the engine piston to expel gaseous products of combustion
therefrom, and to be withdrawn from such space when the combustible charge is
introduced thereinto, substantially as and for the purposes herein described.
Second. Causing the engine piston to make strokes of different lengths, so as at
one stroke to leave a space between the piston and the end of the cylinder for
containing the combustible charge, while at another stroke for expelling the
products of combustion no such space is left, substantially as herein described.
Third. The construction of gas motor engine wherein an auxiliary piston working
in an extension of the engine cylinder is urged by a spring or weight so as to be
intruded into the space behind the engine piston during the expelling stroke, and
is forced back out of such space by the compressed gases. during the compressing
stroke, substantially as herein described with reference to Figs. 1A, 1B, and 2 of the
accompanying Drawings.
Fourth. The construction of gas motor engine wherein an auxiliary piston is
intruded into the space behind the working piston during its expelling stroke by
the action of a cam, but is forced back out of such space by the compressed charge
during the compressing stroke, substantially as herein described with reference to
Fig. 3 of the Drawings.
Fifth. The construction of gas motor engine with two working cylinders, each of
which is provided with an auxiliary piston, the two auxiliary pistons being so
connected that the forcing back of one of them during the compressing stroke of
the one cylinder causes the other auxiliary piston to be intruded into the space
behind its working piston during its expelling stroke, substantially as herein
described with reference to Fig. 4 of the Drawings.
Sixth. The construction of gas motor engine wherein an auxiliary piston is
actuated by a crank or eccentric, so as to be intruded into the space behind the
working piston during the expelling stroke, and to be withdrawn therefrom during
the other stroke or strokes of the piston, substantially as herein described with
reference to Figs. 5 and 7 of the Drawings.
Seventh. The construction of gas motor engine with auxiliary piston for expelling
the products of combustion, wherein the combustible charge is compressed by a
separate pump before being introduced into the engine cylinder, substantially as
herein described with reference to Figs. 64, 6B, and 7' of the Drawings.
Eighth. In a gas motor engine connecting the engine piston to its crank through
the intervention of a spring, so that when the piston is compressing the combustible
charge it will be forced back by the pressure, so as to leave a space between it and
the end of the cylinder for containing such charge, while at the expelling stroke
the piston advances to the end of the cylinder, substantially as described with
reference to Fig. 8 of the Drawings.
Ninth. In a gas motor engine connecting the engine crank to a lever on which

page_text: is mounted a second lever connected at one point to the engine piston, and at
another point to a crank, cam, or eccentric, so arranged as to cause the piston to
make a longer stroke when expelling the products of combustion than when
compressing the combustible charge, substantially as herein described with reference
to Fig. 9 of the Drawings.
In witness whereof, I, the said Charles Denton Abel, have hereunto set my
hand and seal, this Twentieth day of June, in the year of our Lord One
thousand eight hundred and eighty-one.
CHAS. D. ABEL. (L.S.)