IMPROVEMENTS IN GAS AND AIR ENGINES
Year: 1866

page_text: LETTERS PATENT to Charles Denton Abel, of No. 20, Southampton
Buildings, Chancery Lane, in the County of Middlesex, Patent
Agent, for the Invention of "IMPROVEMENTS IN GAS AND AIR ENGINES,"
-A communication from abroad by Eugen Langen and Auguste
Nicol Otto, both of Cologne, in the Kingdom of Prussia.
Sealed the 10th August 1866, and dated the 12th February 1866.
PROVISIONAL SPECIFICATION left by the said Charles Denton Abel
at the Office of the Commissioners of Patents, with his Petition, on
the 12th February 1866.
I, CHARLES DENTON ABEL, of No. 20, Southampton Buildings, Chancery
Lanc, in the County of Middlesex, Patent Agent, do hereby declare the.
nature of the said lnvention for "IMPROVEMENTS IN GAS AND AIR ENGINES," to
be as follows;
In igniting combustible gases inside a closed metallic vessel the heat
generated is imparted to the gaseous products of combustion, which if
prevented from expanding in consequence of such increase of tempera-
ture will exert a proportionate pressure upon the surfaces of the closed
vessel. This pressure would remain constant if no heat were taken
away from the gases, but will in 'reality diminish rapidly in consequence
of the heat generated being absorbed by the metallic surfaces of the
vessel. Experience has shown that the interval of time which elapses
between the heating and consequent expanding of the gases and the sub-

page_text: sequent cooling and consequent contracting of the same is but a very short
one, and therefore in applying the expansive force of such heated gases
as motive power, unless they are allowed to expand very rapidly imme-
diately after the combustion has taken place, a great portion of the heat
that should have produced such expansion will be absorbed by the
cylinder of the engine, and consequently a great proportion of the motive
power will be lost. In employing the ordinary arrangement of con-
necting rod and crank motion for transmitting the expansive force of
the gases behind the piston to the engine shaft, such force has to over-
come not only the work allotted to it but also the inertia of the whole
of the moving parts of the engine, in addition to which the motion of
the piston is controlled in a very prejudicial manner by the action of
the crank; the heated gases are thus prevented from expanding with any-
thing like the requisite rapidity, and a considerable loss of useful effect
consequently takes place as above mentioned.
In the Specification to certain Letters Patent granted to Richard
Archibald Brooman for an Invention of "Improvements in Air and Gas
Engines," being a communication to him from my foreign correspondent,
Auguste Nicol Otto, and bearing date the 24th of August 1863, No. 2098,
it was already proposed to remedy the before-mentioned defect of the
gas engine as heretofore constructed by employing such an arrangement
of engine that upon the ignition of the gases in the cylinder the gaseous
products of combustion were allowed to expand with rapidity without
having to overcome any other resistance than the inertia of a very light
displacing piston, whilst the actual work was subsequently performed by
the pressure of the atmosphere acting against the partial vacuum pro-
duced in the cylinder by the expansion and consequent cooling of the
gases, such pressure being effected against a second piston in the same
cylinder, which piston was cnected to a conrank shaft in the ordinary
manner.
The present Invention has for its object to effect the utilization of the
expansive force of the heated gases upon the same principle as described
in the Specification to the said Letters Patent, but by means of a more
efficient arrangement of the engine, whereby no displacing piston is
required, whilst the action of the working piston is rendered entirely
independent of the motion of the fly wheel shaft, and is capable of being
regulated with the greatest nicety according to the power required. For
this purpose a cylinder placed by preference in a vertical position and
open at the top is provided with a piston, which instead of having a piston
rod connected to the fly wheel shaft by a crank and connecting rod in

page_text: the usual manner, has a rod fixed to it, upon which is formed a rack in
gear with a spur wheel upon the fly wheel shaft; this spur wheel is not
fixed to the shaft, but is so connected to it by means of a description of
ratchet wheel or friction clutch mechanism that when made to revolve
by the rising of the piston and its rack it turns freely upon the shaft,
but when made to turn in the reverse direction by the downward motion
of the piston and rack it causes the shaft to revolve with it. By this
arrangement when the ignition of the mixture of combustible gas and
air takes place beneath the piston the expansive force of the heated
gaseous products of combustion causes the piston to be thrown rapidly
up to the top of the cylinder, no other work being at the time performed
by such motion than the turning of the spur wheel loose upon the fly
wheel shaft. By the time that the piston has arrived at the end of its
stroke the expansion of the gases has cooled them to such an extent
that by their consequent condensation a partial vacuum has been formed
beneath the piston (which latter has indeed performed the last portion of
its up stroke, not by the aid of the expansion of the gases, but by the
momentum which it has acquired) and the pressure of the atmosphere
now consequently forces down the piston and rack, thereby causing the
fly wheel shaft to revolve as described. The mechanism which it is
preferred to employ for the purpose of allowing the spur wheel to revolve
loose upon the fly wheel shaft in one direction, and to carry the shaft
with it when turned in the contrary direction, consists of a disc having
a projecting rim fixed upon the shaft, inside the rim of which disc. is a
second disc loose on the shaft, and connected in an elastic manner to the
spur wheel; this second disc has a number of cam surfaces, between
which and the rim of the first-named disc a number of small wooden
rollers are situated; these rollers jam themselves tight between the cam
surfaces and the rim of the first-named disc when the cam disc and spur
wheel are turned in one direction, and thus cause the rim, disc, and
shaft to revolve with the spur wheel, whilst if the latter is turned in
the reverse direction, the rollers are loosened, and do not cause the rim
disc to revolve with the cam disc. In another arrangement the boss of
the spur wheel is extended somewhat on one side, and has a screw thread
formed upon it; upon this boss one part of a friction clutch fits with a
female screw, while the other part of the clutch is fixed to the shaft.
By turning the spur wheel in one direction the inertia of the moveable
clutch causes the same to screw itself into gear with the fixed clutch,
while if the spur wheel is turned in the reverse direction the moveable
clutch will be screwed out of gear with the fixed clutch. The admission
of the requisite combustible gas and air beneath the piston, and the

page_text: escape of the products of combustion after expansion, is regulated by
cocks or valves actuated by cams upon the fly wheel shaft, and in order
to allow of the action of the piston being rendered independent of the
speed of the shaft such cams are not fixed upon the shaft, but are carried
round therewith by means of a pawl attached to one of the cams taking
into a ratchet wheel fixed upon the shaft. A spring catch is so
arranged that it will, if not prevented, disengage the pawl from the
ratchet wheel, and thus disconnect the cams from the shaft and keep
them stationary every time the shaft has made one revolution. If, how-
ever, the engine is going at full speed, in which case the piston makes
one double stroke for every revolution of the shaft, then as the piston
arrives at the end of the down stroke and the before-mentioned pawl is
approaching the position in which it would be disengaged by the catch,
a stud upon the piston rack is caused to depress such catch, so as to allow
the pawl to pass without becoming disengaged by it, and consequently
without throwing the cams out of gear. If, on the other hand, it is
required that the piston should not make one double stroke for every
revolution of the shaft, owing to a less amount of power being required,
this can be effected by throttling the exit passage of the products of
combustion more or less, whereby the downward motion of the piston
will be more or less retarded towards the end of its stroke, and the stud
on the rack will consequently fail to depress the catch at the moment
when the pawl passes it; the pawl will consequently be thrown out, and
thus the cams which regulate the entrance of the gas for a fresh up
stroke will be kept stationary until by the arrival of the piston and
rack at the end of the down stroke the stud on the latter will depress
the catch, whereupon the cams will again revolve with the shaft, and
will thereby open the gas and air passages for a fresh up stroke. If the
work to be performed by the engine is of a variable nature the closing
more or less of the valve or cock to the exit passage, according as the
load on the engine decreases or increases, may be effected automatically
by means of any suitable known arrangement of "governor" apparatus
driven by the engine. The piston is made at end of down stroke to come
in close contact with the bottom of the cylinder, so as to expel the whole
of the products of combustion. In order, therefore, to allow of the
entrance of the requisite quantity of gas and air it will be necessary to
raise the piston somewhat; this is effected by means of a cam fixed to
and revolving with the other cams before mentioned, which acts upon a
lever in such a manner as to cause it to press against the under side
of the stud upon the piston rack when it has arrived at the end of down
stroke, and thus to raise the piston again somewhat, so as to form a space

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 11th August 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
DENTON ABEL, of No. 20, Southampton Buildings, Chancery Lane, in the
County of Middlesex, Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twelfth day of February, in the year of our
Lord One thousand eight hundred and sixty-six, in the twenty-ninth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Charles Denton Abel, Her special licence that I,
the said Charles Denton Abel, my executors, administrators, and assigns,
or such others as. I, the said Charles Denton Abel, my executors, admi-
nistrators, and assigns, should at any time agree with, and no others, from
time to time and at all times thereafter during the term therein expressed,
should and lawfully might make, use, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands,
aud Isle of Man, an Invention for "IMPROVEMENTS IN GAS AND AIR ENGINES,"
a.communication to me from abroad by Eugen Langen and Auguste Nicol
Otto, both of Cologne, in the Kingdom of Prussia, upon the condition
(amongst others) that I, the said Charles Denton Abel, my executors or
administrators, by an instrument in writing under my, or their, or one
of their hands and seals, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was to
be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date
of the said Letters Patent.
NOW KNOW YE, that I, the said Charles Denton Abel, do hereby declare

page_text: the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
"following statement thereof, reference being had to the accompanying
Drawings, and to the figures and letters marked thereon, that is to say:-
2 In igniting combustible gases inside a closed metallic vessel the heat
generated is imparted to the gaseous products of combustion, which if
prevented from expanding in consequence of such increase of temperature
will exert a proportionate pressure upon the surfaces of the closed vessel;
this pressure would remain constant if no heat were taken away from the
gases, but will in reality diminish rapidly in consequence of the heat
generated being absorbed by the metallic surfaces of the vessel. Experi-
ence has shown that the interval of time which elapses between the heat-
ing and consequent expanding of the gases and subsequent cooling and
consequent contracting of the same is but a very short one, and therefore
in applying the expansive force of such heated gases as motive power,
unless they are allowed to expand very rapidly immediately after the
combustion has taken place, a great portion of the heat that should have
produced such expansion will be absorbed by the cylinder of the engine,
and consequently a great proportion of the motive power will be lost.
In employing the ordinary arrangement of connecting rod and crank
motion for transmitting the expansive force of the gases behind the piston
to the engine shaft, such force has to overcome not only the work allotted
to it but also the inertia of the whole of the moving parts of the engine;
in addition to which the motion of the piston is controlled in a very pre-
judicial manner by the action of the crank. The heated gases are thus
prevented from expanding with anything like the requisite rapidity, and
a considerable loss of useful effect consequently takes place as above
mentioned.
*:*
In the Specification to certain Letters Patent granted to Richard
Archibald Brooman for an Invention of "Improvements in Air and
Gas Engines," being a communication to him from my foreign corre-
spondent, Auguste Nicol Otto, and bearing date the 24th of August 1863,
No. 2098, it was already proposed to remedy the before-mentioned defect
of the gas engine as heretofore constructed by employing such an arrange-
ment of engine that upon the ignition of the gases in the cylinder the
gaseous products of combustion were allowed to expand with rapidity
without having to overcome any other resistance than the inertia of a
very light displacing piston, whilst the actual work was subsequently
performed by the pressure of the atmosphere acting against the partial
vacuum produced in the cylinder by the expansion and consequent cool-
ing of the gases, such pressure being effected against a second piston in

page_text: the same cylinder, which piston was connected to a crank shaft in the
ordinary manner.
The present Invention consists in so arranging engines working on the
principle above set forth that the hot gases in expanding instead of acting
upon a separate displacing piston, as in the above-described arrangement,
are made to act directly upon the working piston, which in performing
its stroke consequent upon such action moves entirely independent of the
engine shaft, and consequently without performing any work, while when
it is caused to move in the contrary direction by the pressure of the
atmosphere against the partial vacuum formed behind it, it is connected
to the engine shaft and causes the same to revolve.
Figures 1 to 8 on Sheets I. and II. of the accompanying Drawings show
one arrangement of engine, whereby the before-described Invention may
be carried into practice. Figure 1 shows a vertical section of the engine;
Figure 2 shows an end elevation of the same; Figure 3 shows a side
elevation partly in section; Figure 4 shows a plan also partly in section,
and Figures 5 to 8 show detached elevations and sections of details.
Similar letters of reference indicate similar parts in each of the Figures..
A is a cast-iron cylinder closed at bottom in an air-tight manner by the
cover B; this cylinder is surrounded by a cold-water jacket W open at
top, the water in which serves simply to distribute the small amount of
heat imparted to the cylinder at bottom equally throughout its length,
and only requires renewing about once a month; C is a separate casting,
having two cocks; D and E, a flap valve; F, the entrance pipe G for the
combustible gases, and the exit pipe H for the products of combustion;
J is a metal piston to which is fixed the rod K upon which a rack is
formed; this rod is guided in its motion by a guide & fixed upon the upper
open end of the cylinder A, upon which are furthermore fixed two
brackets L, L', supporting the fly wheel shaft M and the spindle N. Upon
the shaft M are fixed the fly wheel O, the rim disc P of a clutch apparatus,
the ratchet wheel Q, and the driving pulley R, while loose upon the shaft
are three cams S', S³, S", which are connected together in fixed relative
positions. Inside the rim disc P is situated a disc T having cam surfaces
upon its circumference, and connected in an elastic manner to a spur
wheel U, both being made to run loose upon the boss of the disc P. The
spindle N is fixed in its bearings and carries loose upon it and inde-
pendent of each other three levers v', 3, ³, and the disengaging catch w.
The excentric or cam S¹ carries a pawl a, by means of which the three
cams are connected to or disconnected from the shaft M, according as
the pawl is put in or out of gear with the ratchet wheel Q fixed upon
the shaft, the throwing out of gear of the pawl being. effected by the dis-

page_text: engaging catch.w in a manner to be hereafter described. The piston rod
rack K is in gear with the spur wheel U, which is coupled to the cam
disc T in an elastic manner by means of a projecting stud y, on each
side of which is situated a piece of india-rubber' Z, shewn at Figure 5.
The rim disc P and cam disc T form together with the 'small wooden
rollers a, a, a clutch apparatus shown separately in Figures 5 and 6,
by means of which, the spur wheel U can turn loose upon the shaft M in
the direction of the blue arrow, Figure 1, but is caused to carry the shaft
with it if turned in the direction of the red arrow.
The action of this apparatus is as follows:-If the piston J is raised the
piston rod rack K turns the spur wheel in the direction of the blue arrow
independent of the shaft; if on the other hand the piston is. moved down-
wards the cam disc T, in endeavouring to turn in the reverse direction,
jams the wooden rollers a, a, tight between its cam surfaces and the rim
of the disc P, whereby the latter, and consequently also the shaft M,
is forced to rotate with the disc T in the direction of the red arrow. For
the clutch apparatus. to be certain. in its action it is only necessary to
insure that the angle that the cam surfaces form with the rim of the disc
P is less than the slipping angle of wood upon iron. By the above
arrangement. it will be seen that at every up stroke of the piston such
motion simply effects the turning of the spur wheel U loose upon the
shaft M, whilst at every down stroke of the piston such motion will be
imparted to the shaft in the direction of the red arrow, whereby the
work of the engine will be performed. If we suppose such motion to be
taking place and the position of the moving parts to be that shown in
Figure 1, then the cam S will begin to depress the one arm of the
lever ; the other arm. of which will begin to open the cock D to the gas
pipe G, by means of the rod f and lever d, and will thus establish a
communication between the gas. pipe G and air passages o, o, and the
bottom of the cylinder. At the same time the cam S³ effects the turning
of the cock E by means of the rod g and lever e, so as to cut off the com-
munication between the cylinder and the exit pipe H. When the shaft.
M has turned a little further the cam S' depresses the one arm of the
lever ', the other arm of which is made thereby to raise the piston J
somewhat by pressing against the under side of a stud h upon the piston
rod K. The area of the gas and air passages being properly proportioned
the space that is formed below the piston by the raising of the same is
filled with an explosive compound, and by the time the piston has been
raised to the required extent the motion of the shaft has caused the
cock D. to turn. so as to cut off the communication with the gas and air
passages. Simultaneously an electric spark passes between the ends of.

page_text: the insulated wires 1, 1, the passing of the requisite electric current for
this purpose being produced by any known arrangement of galvanic
battery and current breaker actuated by the shaft M; an explosion of
the combustible gas in the cylinder instantly takes place, and the expan-
sive force of the heated gaseous products of combustion throws the piston
rapidly upwards in the cylinder, thereby turning the spur wheel U. and
the disc T in the direction of the blue arrow. As the gases expand
beneath the piston they become rapidly cooler, and lose their expansive
force, so much so indeed that they cease to exert any such force upon the
piston before it has completed its up stroke, the last portion of which
is effected against the pressure of the atmosphere solely by virtue of the
momentum which has been imparted to the piston at the commencement
of the stroke. By the time that the piston has arrived at the top of its
up stroke, the cooling of the gases, consequent on their expansion and
to a small extent on the absorption of some of their heat by the surfaces
of the cylinder, has caused them to contract to the volume which they
occupy under a low temperature, whereby a partial vacuum is produced
in the cylinder below the piston, and the pressure of the atmosphere in
acting against such vacuum now forces the piston downwards, whereby
the turning of the shaft M is effected, and consequently the work of
the engine performed as before described. As the piston approaches
the bottom of down stroke the cam S turns the cock E so as to effect
a communication between the cylinder and the passage i leading to the
escape pipe H, and the piston in falling by its own weight to the bottom of
the cylinder forces the condensed gaseous products of combustion
through the flap valve F into the escape pipe H. The object of the
valve F is to prevent atmospheric air from passing into the cylinder
through the pipe H, should the cock E begin to open before the piston
has arrived in such a position that no partial vacuum exists beneath it.
The gas pipe is provided with a cock not shown on the Drawing, by means
of which the quantity of gas that passes into the cylinder at each stroke
may be so regulated that by its explosion the piston is only thrown up
in the cylinder to a certain height, and thus the power of the engine
decreased or increased as may be required. As, however, the useful
effect of the engine is greatest when the piston is raised to a certain
height, it is preferable to regulate the power of the engine in such a
manner that the stroke of the piston always remains the same, while the
number of strokes during a certain interval is made to vary according
to the power required, and independently of the speed of the shaft M,
which may be considered as constant, so that when a greater amount of
power is required of the engine the piston makes a greater number of

page_text: strokes, while if a less amount of power is required the piston makes a
less number of strokes in a given time. For this purpose the action of
the valve gear of the engine is rendered independent of the speed of the
engine shaft by the following arrangement:-If the catch w were not in
existence the cams S actuating the valves would be permanently con-
nected to the engine shaft by means of the pawl x and the ratchet wheel
Q, and consequently at each revolution of the shaft the piston would
perform one up and down stroke. The catch w is, however, acted upon
by a spring w', so as if not depressed to assume the position shown in
blue lines in Figures 2 and 8, in which position it will strike against the
arm of the pawl when this has performed one revolution together with
the cams, and in thus putting the pawl out of gear with the ratchet wheel
Q, the catch will cause the cams to remain stationary until by the down-
ward motion of the piston the stud / upon the piston rod strikes against
the arm of the catch w and depresses it, so as to allow of the pawl being
put into gear with the ratchet wheel by the action of the spring n. As
soon as this takes place the cams S again revolve with the shaft and
actuate the valves or cocks as described. The pipe H is provided with
a cock p, by closing which more or less the exit of the condensed products
of combustion from the cylinder may be more or less throttled, and thus
the downward motion of the piston towards the end of the stroke more
or less retarded. If the cock p is full open the piston arrives at the end
of its down stroke just in time for the stud h to depress the catch w
before the pawl x passes the latter, and thus to prevent the cams S being
thrown out of gear. Under these conditions the piston performs one up
and down stroke for every revolution of the crank shaft, and the engine
works with its maximum power. If it is required to reduce the power
of the engine, then by throttling the escape pipe H the downward motion
of the piston is retarded, and the stud consequently fails to depress
the catch w at the required moment, so as to allow the pawl x to pass;
the latter is consequently thrown out of gear and the cams S are caused
to remain stationary until the piston arrives in the position for depressing
the catch. The pawl x then springs in gear with the ratchet wheel Q,
and the cams S begin to move so as to open the gas and air passages for
a fresh up stroke. By this arrangement the piston can be made to
perform any less number of double strokes than the shaft M performs
revolutions in a given time. It will be seen that although in performing
the first part of the down stroke the piston must necessarily move with
the same speed as the shaft M, yet the before-described retardation of
the motion of the piston at the end of the stroke can take place, because
as soon as the motion of the piston is checked the rollers a, a, of the clutch

page_text: apparatus loosen their hold and the spur wheel U runs loose upon the
shaft. If the work that the engine has to perform is not of a uniform
nature the power can be regulated in the above-described manner auto-
matically by the application of any suitable known form of governing
or regulating apparatus, such as the ordinary conical pendulum, which
in receiving motion from the engine shaft may be made to close the
throttle valve of the escape pipe more or less as the load on the engine
decreases or increases.
In the above-described arrangement in place of the clutch contrivance
described for rendering the spur wheel U alternately fast and loose on
the shaft M as described, the arrangement shown in section at Figure 7
may be employed. In this case the spur wheel U has a projecting boss
U formed on one side of it, upon which boss is formed a screw thread
as shown. Upon this boss the moveable part T of a friction clutch fits
with a female screw, while the other part P of the clutch is fixed on
the shaft M. From this arrangement it will be seen that if the wheel U
is turned in one direction by the up stroke of the piston it will screw.
the clutch T towards it, and consequently out of gear with the part P,
and the wheel U will then run loose upon the shaft, whereas if the wheel
U is turned in the reverse direction the clutch T is screwed towards the
fixed part P, so that the grooved rings g are pressed into each other, and
the wheel is thus made fast with the shaft. In place of imparting the
motion of the piston to the engine shaft in the manner above described,
an arrangement may be employed as indicated in Figures 9 and 10 on
Sheet II. of the Drawings, which show respectively an elevation and a
vertical section of a modified arrangement of the engine. Here the spur
wheel U of the former arrangement is replaced by a lever or crank U;
the boss of which fits loose upon the shaft M, while the other end is
hinged to a forked connecting rod K', the lower end of which hinged to
the piston J. The lever U receives a reciprocating motion from the
piston J by means of the connecting rod K', forming an angle of about 45°
above and below the horizontal line at the end of each stroke, as indi-
cated in Figure 9, and it is connected to the moveable part of a clutch
apparatus upon the shaft M in such a manner that in performing the
up stroke it turns loose on the shaft, while when performing the down
stroke it causes the shaft M to turn with it. The clutch apparatus for
this purpose may be arranged either as described with reference to
Figures 1 to 8, or as shown at Figure 9, where the lever: U is connected
by a link to a second lever U' which works on a pin y carried by a bar T;
this bar is connected to a second bar T¹ by means of a link Q. the one
end of which fits upon an excentric w formed on the back of the lever U':

page_text: The ends of the bars T, T', when in the relative position shown on the
Drawing, that is, when the lever U is commencing its up stroke, fit loosely
inside the rim of the disc P fixed on the shaft M, such relative position
of the bars T, T', remaining the same during the entire up stroke on
account of the end of the lever U₁ resting against the stud t on the
bar T. When the lever U commences its downward motion, however,
it draws the lever U¹ down with it, and by thus turning the excentric w
forces the two bars T, T', apart, and thereby causes the ends of the same
to be jammed tight in the rim of the disc P, which together with the
shaft M is thus caused to move with the lever U. Upon the circumference
of the disc P are formed the cams S, S, acting upon the lever v for
slightly raising the piston J at the end of each down stroke, the piston
being in this case arranged to work with a constant speed of two up
strokes for every revolution of the shaft M, for which purpose also
the admission of gas and air is in this case regulated by means of a
revolving valve D, receiving motion from the shaft M by means of a pair
of bevil wheels as shown. The other parts of the engine are designated
by the same letters of reference as the corresponding parts in the previous
arrangement, and need not be further described.
Figures 11 to 15 on Sheet III. of the accompanying Drawings show
another modification of the improved engine. Figure 11 shows a sectional
elevation of the same; Figure 12 shows à diagram of the positions of the
excentrics, and Figures 13 to 15 show enlarged details of the regulating
slide D. In this arrangement the motion of the engine shaft M is
imparted to the mill shaft H by means of an endless band P passing over
the pulleys m and h, and the piston J is caused to impart only its down-
ward motion to the endless band P in the following manner:-To the
piston J are fixed two piston rods K, a slight distance apart, connected
together at top by means of a piece Q, which slides upon a rod k of a
rectangular transverse section fixed to the top of the cylinder A, and
situated between the two piston rods, to which it acts as a guide. Upon
this rod is a second sliding piece U carrying two levers u, hung upon
pins on each side of the slide U. The one end of each of these levers
is connected by a link g to the piece Q, while the other end is hinged
to the plate T. The endless band P passes between the plate T and the
slide U, and the levers u are placed in such a position that on commencing
the up stroke the piston rods, with the connecting piece Q, in approaching
the slide U and coming in contact with the end thereof so as to impart
their motion to it, cause the levers u to move the plate T away from the
slide U, whereby the band P passes perfectly free between the two, and
the piston J consequently performs its up.stroke quite disconnected from

page_text: the engine shaft; on the other hand when the piston commences its down-
ward motion the piston rods in moving away from the slide U before
imparting their motion to it draw the levers and with them the plate T
into such a position that the band P is jammed tight between the plate T
and the slide U, and the piston J in performing its down stroke is there-
fore caused to impart its motion by means of the band P to the shafts M
and H, as in the previous arrangements. The admission of combustible
gas and air into the cylinder, and the escape of the products of com-
bustion therefrom, is in this arrangement effected by means of a slide
valve D, actuated by means of an excentric S' on the shaft N, whilst a
second excentric S effects the raising of the piston J at the end of down
stroke, as before described, by means of the lever pressing against a
stud won the piston rod. The shaft N, upon which the excentrics are
fixed, receives for this purpose a periodical rotary motion from the shaft
M by means of a friction wheel 1 on the latter in gear with a space
friction wheel 2 on the former, the space wheel remaining stationary
at the end of every revolution when the space comes round to the point
of contact between the two. The length of time during which the shaft
N remains stationary is regulated by the motion of the piston J, the
piston rod K of which is provided with a stud x, which as the piston
approaches the end of down stroke comes in contact with a stud ¹ upon
the space wheel 2, and thus turns the latter slightly in the direction of
the arrow, so as to bring it in gear with the friction wheel 1 again, and
thus to cause it to perform another revolution, whereby the excentrics
S1, S2, effect respectively the motion of the slide valve D, and the raising
of the piston at the end of its down stroke. When the shaft N is
stationary the position of the excentric S¹ must be such as to cause the
slide valve D to effect a communication between the interior of the
cylinder A and the aperture 3 in the valve box 4 by means of the
passage 5.
By means of the valve 6, however, the communication
between the cylinder A and the atmosphere is cut off as long as there is
any partial vacuum in the cylinder. The several positions of the excentrics
are indicated at the Diagram, Figure 12. If the shaft N is stationary
the excentric S₁ is in the position 7, and therefore the slide valve D is
in the middle position with the passage 5 effecting the communication
between the cylinder and the atmosphere as before mentioned. The
excentric S on the other hand is at that time situated at its lowest
point 8, being at right angles to S', and consequently the lever is in
its lowest position. When the shaft N commences its motion the slide
valve moves downwards, and when the excentric S) has arrived at the
point 9 the communication between the cylinder and the atmosphere is

page_text: cut off, while a communication is established by the passage 10 of the
valve between the cylinder and the air, and gas passages 11 and 12.
At the same time the excentric S has moved to the point 13, and con-
sequently the lever begins to raise the piston J. Air and gas there-
fore now pass into the cylinder while the excentric S' and with it the
slide valve moves down from point 9 to 8 and rises again from 8 to 13*.
The excentric S has during the same time moved from 13 to 14, and con-
sequently the piston J has been raised to its full height preparatory to the
ignition of the gases; arrived at point 13* the excentric S¹ causes the
communication between the gas and air passages and the cylinder to be
cut off, and when it has risen to 15 the ignition of the gases in the
cylinder takes place. The aperture 16 to the cylinder remains closed by
the slide valve until the excentric S¹ has reached the point 17; the
passage 5 then again commences to establish a communication between
the cylinder and the atmosphere, and by the time the excentric S' reaches
the point 7 again such communication is full open, and now remains
so in consequence of the shaft N and excentrics coming to a standstill.
When the piston has arrived at the end of down stroke the motion of
the shaft N and the action of the excentrics and slide valve commence
as before. :
The ignition of the mixture of gas and air in the cylinder may in this
case be effected by a lighted gas jet instead of by an electric spark, the
arrangement of the valve for which purpose is shown in the section of
the slide valve at Figure 14.
The passage 18 is so formed as to establish a communication between
the passage 19 and aperture 20, when the valve D is in its lowest posi-
tion. At the same time the communication between the aperture 16
to the cylinder and the passage 18 is cut off by the part 21 of the valve,
while a communication is established between the passages 18 and 22 by
the channel 23; through 22 combustible gas now passes into the passage
18, where it becomes mixed with air entering through the aperture 20.
This mixture in escaping through the passage 19 becomes ignited by
a gas jet 24, kept constantly burning, and while the gas is being ignited
and burns in the passage 18 the valve moves up so as to establish a com-
munication between such passage and the cylinder opening 16, and thus
the ignition of the explosive mixture in the cylinder is effected.
The mode of regulating the power of the engine by controlling the exit
of the waste gases is effected in a similar manner to that described in the
first arrangement, and need, therefore, not be further described.
Having now described the nature of this Invention, and the manner
in which it is to be performed, I wish it to be understood that I do not

page_text: limit myself to the precise arrangements of the improved engine herein-
before described with reference to the accompanying Drawings, as these
may be variously modified without departing from the nature of the
Invention; thus the engines may be arranged either in a vertical position
as shown, or in an inclined or horizontal position, in which latter case
the action of gravity upon the piston in performing the last portion of its
down stroke, as before described, may be replaced by the action of a
spiral spring connected in any suitable known manner to the piston rod,
so that the forward stroke of the piston causes the spring to be wound
up, while during the back stroke the spring in unwinding presses upon
the piston in the manner required. Also, if greater power is required
of the engine than can be advantageously afforded by one single cylinder,
two or more cylinders may be made to act upon one and the same driving
shaft.
Furthermore, I wish it to be understood that I do not claim as of itself
forming part of this Invention, the arrangement herein-before described
for igniting the explosive mixture in the cylinder by means of a gas jet
instead of by means of an electric spark, but what I claim is,-
First. So constructing gas and air engines having only one piston in
the cylinder, that such piston while being impelled by the expansive force
of the ignited gases performs its stroke quite independently of the engine
shaft, but is caused to carry the shaft with it while performing the return
stroke under the pressure of the atmosphere against the partial vacuum
formed behind the piston, substantially as herein-before described with
reference to the accompanying Drawings.
Second. So arranging the valve gearing to gas and air engines, as also
the connection of the piston to the engine shaft, that the number of
strokes made by the piston may be varied independently of the speed of
the engine shaft, substantially as herein-before described with reference
to the accompanying Drawings.
In witness whereof, I, the said Charles Denton Abel, have hereunto
set my hand and seal, this Eighth day of August, in the year of
our Lord One thousand eight hundred and sixty-six.
CHARLES D. ABEL. (L.S.)