IMPROVE- MENTS IN GAS MOTOR ENGINES
Year: 1876

page_text: LETTERS PATENT to Charles Denton Abel, of No. 20, Southampton Buildings,
Chancery Lane, in the County of Middlesex, for the Invention of "IMPROVE-
MENTS IN GAS MOTOR ENGINES." A communication from abroad by Nicolaus
August Otto, of the Gas-Motoren Fabrik-Deutz, at Deutz, in the German
Empire.
Sealed the 1st August 1876, and dated the 17th May 1876.
PROVISIONAL SPECIFICATION left by the said Charles Denton Abel at the
Office of the Commissioners of Patents on the 17th May 1870.
CHARLES DENTON ABEL, of No. 20, Southampton Buildings, Chancery Lane,
in the County of Middlesex. "IMPROVEMENTS IN GAS MOTOR ENGINES."
In gas motor engines as at present constructed, an explosive mixture of com-
bustible gas and air is introduced into the engine cylinder, where it is ignited,
resulting in a sudden expansion of the gases and development of heat, a great
portion of which is lost by absorption unless special provisions are made for
allowing the gases to expand very rapidly.
According to the present Invention combustible gas or vapour is introduced into
the cylinder together with air or other gas that may or may not support com-
bustion, in such a manner that the particles of the combustible gas are more or
less dispersed in an isolated condition in the air or other gas, so that on ignition
instead of an explosion ensuing, the flame will be communicated gradually from
one combustible particle to another, thereby effecting a gradual development of
heat, and a corresponding gradual expansion of the gases, which will enable the
motive power so produced to be utilized in the most effective manner.
The mode
of using the gases and the arrangement of the engine may be variously modified
in carrying out this Invention.
Thus according to one arrangement the gases are introduced into the engine
cylinder at atmospheric pressure. The cylinder is for this purpose provided
with a slide having suitable ports for the admission of air, and of an intimate
mixture of combustible gas and air, and the movement of the slide is so regulated
by means of a cam or eccentric on the engine shaft that during the first part of
the stroke of the piston air alone enters the cylinder, while during a succeeding
portion of the stroke the mixture of gas and air is introduced behind the air; this
4

page_text: mixture in entering the cylinder will become more or less dispersed in the air
previously introduced, the particles of the mixture being situated nearest together
at the point where they enter the cylinder, and becoming gradually more dispersed
as they mix with the air in front. A communication being now established by
the slide between a small external gas flame and the contents of the cylinder at
the point where the combustible mixture is most dense, this ignites, and the
combustion of the whole charge takes place gradually, the mixture burning with
gradually decreasing rapidity as the flame extends to those particles that are more
diffused among the air. The gradual expansion of the gases thus produced causes
the piston to complete its stroke, and on the return stroke, which may be effected
either by the momentum of the fly wheel, or by the introduction of a similar
charge at the other end of the cylinder, the products of combustion are expelled
through a valve, after which the above described operation is repeated for the
next stroke.
According to another arrangement the combustible gas and air or other gas are
employed in a compressed state in the engine. For this purpose the engine may
operate either as above described, the gas and air being simply compressed to the
requisite degree before being introduced into the cylinder, or by preference the
compression is effected in the cylinder itself in the following manner-The cylinder
is constructed of greater length than the stroke of the piston, so that there is a
space beyond the latter when it is at end stroke. Assuming this space to be filled
with a portion of the gaseous products of combustion resulting from the last stroke
at atmospheric. pressure, the piston in performing one part of its stroke draws in
atmospheric air, after which it will draw in the combustible mixture during the
remainder of its stroke. The cylinder will then be filled with three strata of
different gases, more or less intermingled at their junction, namely, a stratuin of
products of combustion next the piston, then a stratum of air, and lastly the
combustible mixture. The piston then performs its return stroke, whereby the
gascous charge is compressed into the before-mentioned space at the end of the
cylinder. The gases will in this condition still retain their stratified position,
the particles of combustible mixture being diffused to a certain extent through
the other strata. The charge is now ignited and burns gradually, and with the
same effect as described with reference to the first arrangement. On the return
stroke the products of combustion are expelled with the exception of the quantity
contained in the space at the end of the cylinder.
The regulation of the power of the engines operating according to the above-
described Invention is effected simply by admitting more or less of the combustible
gas for each charge, this being done by regulating the time of opening and closing
of an admission valve on the gas supply pipe. The motion of the slide is regulated
by a rotating cam, capable of being adjusted on its shaft relatively to a lever
connected to the slide, which adjustinent may be effected by any suitable known
arrangement of governor.
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 3rd
November 1876.
A com-
CHARLES DENTON ABEL, of No. 20, Southampton Buildings, Chancery Lane,
in the County of Middlesex. "IMPROVEMENTS IN GAS MOTOR ENGINES."
munication from abroad by Nicolaus August Otto, of the Gas-Motoren Fabrik-
Deutz, at Deutz, in the German Empire.
In gas motor engines as at present constructed an explosive mixture of combus-
tible gas and air is introduced into the engine cylinder where it is ignited, resulting
in a sudden expansion of the gases and development of heat, a great portion of

page_text: which is lost by absorption unless special provisions are made for allowing the gases
to expand very rapidly.
According to the present Invention combustible mixture of gas or vapour and
air is introduced into the cylinder together with air or other gas that may or may
not support combustion in such a manner that the particles of the combustible
mixture are more or less dispersed in an isolated condition in the air or other gas,
so that on ignition, instead of an explosion ensuing, the flame will be communicated
gradually from one combustible particle to another, thereby effecting a gradual
development of heat and a corresponding gradual expansion of the gases, which will
enable the motive power so produced to be utilised in the most effective inanner.
The mode of using the gases and the arrangement of the engine may be variously
nodified in carrying out this Invention.
Thus according to one arrangement the gases are introduced into the engine
cylinder at atmospheric pressure. The cylinder is for this purpose provided with
a slide having suitable ports for the admission of air and of an intimate mixture
of combustible gas or vapour and air, and the movement of the slide is so regulated
by means of a cam or eccentric on the engine shaft that during the first part of
the stroke of the piston air alone enters the cylinder, while during a succeeding
portion of the stroke the mixture of gas or petroleum vapour and air is introduced
behind the air. This mixture in entering the cylinder will become more or less
dispersed in the air previously introduced, the particles of the mixture being situated
nearest together at the points where they enter the cylinder, and becoming
gradually more dispersed as they mix with the air in front. A communication
being now established by the slide between a small external gas flame and the
contents of the cylinder at the point where the combustible mixture is most dense,
this ignites and the combustion of the whole charge takes place gradually, the
mixture burning with gradually decreasing rapidity as the flame extends to those
particles that are more dispersed among the air. The gradual expansion of the
gases thus produced causes the piston to complete its stroke, and on the return
stroke, which may be effected either by the momentum of the fly wheel or by the
introduction of a similar charge at the other end of the cylinder, the products of
combustion are expelled through a valve, after which the above described operation
is repeated for the next stroke.
According to another arrangement the combustible gas and air or other gas are
employed in a compressed state in the engine. For this purpose the engine may
operate either as above described, the gas and air being simply compressed to the
requisite degree before being introduced into the cylinder, or by preference the
compression is effected in the cylinder itself in the following inanner:-The cylinder
is constructed of greater length than the stroke of the piston, so that there is a space
beyond the latter when it is at end stroke. Assuming this space to be filled with a
portion of the gaseous products of combustion resulting from the last stroke at atmo-
spheric pressure, the piston in performing one part of its stroke draws in atmospheric
air, after which it will draw in the combustible mixture during the remainder of
its stroke. The cylinder will then be filled with three strata of different gases, more
or less intermingled at their junction, namely, a stratum of products of combustion
next the piston, then a stratum of air, and lastly the combustible mixture. The
piston then performs its return stroke, whereby the gaseous charge is compressed
The gases will in this
into the before-mentioned space at the end of the cylinder.
condition still retain their stratified position, the particles of combustible mixture
being diffused to a certain extent through the other strata. The charge is now
ignited and burns gradually and with the same effect as described with reference
to the first arrangement. On the return stroke the products of combustion are
expelled with the exception of the quantity contained in the space at the end of
the cylinder.
The regulation of the power of the engines operating according to the above
described Invention is effected simply by admitting more or less of the combustible
gas for each charge, this being done by regulating the time of opening and closing

page_text: by a rotating cam capable of being adjusted longitudinally on its shaft by any
suitable known arrangement of governor.
DESCRIPTION OF THE DRAWINGS.
In the accompanying Drawings Fig. 1 shews a longitudinal section of an engine
cylinder A, having a piston B connected to a fly wheel shaft, an inlet passage C
controlled by the slide D, and a passage F for the emission of the products of
combustion closed by a valve F. When the piston is at the end of its in stroke its
inner surface being at a the slide D is in such a position that as the piston begins
its out stroke air entering by the aperture D2 passes by D and C into the cylinder.
When the piston has reached the point b the slide has moved so as to admit
combustible gas or vapour from the passage G to mix with the entering air until
the piston reaches the point c, when the slide has moved back to the position
shewn, cutting off the gas and air supply and about to establish a communication
between a small gas flame H and the charge in the cylinder. The combustible
gaseous mixture entering the cylinder behind the air previously admitted, becomes
partially mixed therewith, being thus dispersed more and more towards the
piston, as indicated by the dots in the Drawing, which represent the combustible
particles. On the ignition of the charge the combustion at and near the port C is
comparatively rapid, but as the ignition extends towards the front of the charge
it proceeds more and more slowly, owing to the greater dispersion of the combustible
particles. The gradually increasing pressure thus produced by the gradual expansion
of the products of combustion, and also of the surrounding fluid, due to the heat evolved,
causes the piston to complete its outstroke, imparting motion to the fly wheel, the
momentum of which causes the piston to perform its return stroke, expelling the
products of combustion through the valve F, and also causing the piston to
commence its next out stroke and draw in a fresh charge of air and gas. In
order to vary the power of the engine the charge of gas or the proportion of the
air and gas or vapour may be varied, and such variations may be controlled by
means of a governor, as will be presently described. By this mode of operating
shock resulting from sudden explosion is avoided, partly through the dispersion of
the combustible charge, as described, and partly because the first admitted charge
of air which does not become completely mixed with the combustible charge acts
as a cushion between this and the piston, and owing to the gradual development of
heat and expansion of the gases there is comparatively little loss of useful effect.
Engines operating in this manner may either be single acting as shewn, the
return stroke being effected by the momentum of the fly wheel, or they may
be double acting, having a charge introduced at each end of the cylinder.
They may also operate with the gases at atmospheric pressure or compressed to
any desired degree. In the latter case the engine may be like that above 4
described supplied with compressed gases, I prefer, however, to dispense with
compressing mechanism by arranging the engine to operate as I will now
describe, referring to Figs. 2 to 13 of the Drawings. Fig. 2 shews a side elevation;
Fig. 3 a sectional plan; Fig. 4 a back end view of an engine thus arranged; and
Figs. 5 to 13 shew details of the valve gear. This engine being single acting, 4
the cylinder A is open in front, at its closed back end it has, beyond the stroke
of the piston B, a space A' preferably of conical form tapering to the inlet
port C, and also communicating by a passage E with a valve F (Fig. 3) for
discharging the products of combustion. The piston B is connected by the rod B₁
to the crank shaft I, on which is a bevil pinion I in gear with a bevil wheel K, on 5
a shaft K. On the other end of this shaft is a crank K, connected by a link D
to the slide D, which governs the admission of gas and air to the cylinder. The
gearing 1, K1, is proportioned as 2 to 1, so that the crank K makes one revolution,
and consequently the slide makes one to and fro motion while the piston makes two
double strokes. When the piston is at the point a, the end of its in stroke, and 5

page_text: about to be moved outwards by the momentum of the fly wheel M, then the slide
D (the construction of which will be hereafter explained) is in position to admit air
through the passage D' and port C into the cylinder until the piston reaches the
point b, when the slide attains such a position that combustible gas is drawn in
together with air until the piston reaches the end of its out stroke, as shewn in Fig.
3. As before explained with reference to Fig. 1, the combustible mixture in partially
mingling with the air previously introduced is more and more dispersed towards
the front. The slide having now closed the inlet port C, the piston is caused by the
momentum of the fly wheel to perform its in stroke, compressing the charge of gas
and air into the space A¹ behind a, the combustible particles remaining in nearly
the same unequally distributed condition as before compression. The slide now
moves so as to admit the gas flame H, igniting the charge, and the combustion
produces a gradual development of heat and expansion of the gases, whereby the
piston is caused to perform its out stroke, imparting fresh momentum to the fly
wheel. This momentum again causes the piston to perform its in stroke, expelling
the products of combustion through the valve F, which is opened by a lever F,
acted on by a cain F" on the shaft K. As the piston only moves back to a, a portion
of the products of combustion remaining in the cylinder will partially mix with the
air drawn in at the next out stroke, but as the combustible mixture afterwards
introduced can burn independently of the gas surrounding its particles, the presence
of these products of previous combustion will merely aid in preventing too rapid or
explosive combustion and in acting as a cushion between the combustible charge
and the piston. It will be evident that if the space A', or a separate chamber such
as an air vessel communicating therewith, be made sufficiently large to contain the
whole quantity of incombustible fluid requisite for each charge, no fresh charge of air
need be drawn in at the commencement of the stroke. As before stated, the power of
the engine may be regulated by regulating the quantity of combustible gas introduced
at each charge. This is effected by the gas slide P, controlled by a governor Q,
operating on a sliding can R. Fig. 5, shews an enlarged front view of the gas slide,
Figs. 6 and 7 vertical sections, and Fig. 8 a plan of the same. In the casing are
two passages G and G, the former communicating by a pipe G³ with the gas
passage G in the cover L of the main slide, and the latter with the gas supply pipe
G. These passages have small side openings as shewn, which, when the slide Pis
as shewn in Fig. 7, both communicate with the cavity of the slide so that gas can
pass from Ginto G', and thence to the main slide D; when the slide is moved into the
position shewn in Fig. 6 this communication and consequently the gas supply is cut
off. On the slide P is mounted a roller P, bearing upon a cam R, which revolves
with and can slide longitudinally along the shaft K. The slide is raised by the cam
and is pressed down by a spring P. According as the can is shifted relatively to
the roller P by the action of the governor Q and lever Q (which has a fork taking
into a collar on the cam), the slide is made to establish the communication between
Gand G for a longer or a shorter period, thus allowing a greater or less quantity
of the combustible gas to pass into the cylinder A independently of the action of
the slide D. The gas slide P is held against the face of the casing by a spring P³
pressing against a cover P' on the back of the slide. The construction and mode of
operating of the engine slide D will be understood on reference to Figs. 10 to 13,
of which Figs. 10 and 11 represent longitudinal sections on the line Z, Z, of Fig. 12
of the slide D and its casing, shewing the slide in two different positions. Figs. 12
and 13 are transverse sections respectively on line X, X, and Y,Y, of Fig. 10. Fig. 9
represents diagrammatically the path of the crank K2, in which the part 1 to 2
represents the motion of the slide during the time that the piston in its out stroke is
drawing in the gaseous charge, the part from 2 to 3 the motion during the com-
pression of the charge by the return stroke of the piston, 3 to 4 the motion during
the working out stroke of the piston, and 4 to 1 the motion during the expulsion of
the products of combustion by the last in stroke of the piston. Fig. 10 shews, first,
the position of the slide at the point 1 of the crank path when the air passage D'
is just about to communicate with the port C; and, secondly, its position at point 2,

page_text: when the gas and air supply is just cut off. Although in the first position the gas
passage G is about to open, the gas 'slide P prevents the admission of combustible
gas until the requisite charge of air is first introduced. Fig. 11 shews, firstly, the
position of the slide at the point 3 when the flame of the gas jet H is about to be
communicated to the gaseous charge by a small quantity of ignited gas in the passage
D"; and, secondly, its position at the point 4 when the escape valve F is about to be
opened. For effecting the ignition of the charge a small quantity of combustible gas is
made to pass down a pipe S into a recess S¹ in the end of the cylinder, whence it issues
through a small channel D' in the slide into the passage D³. Here it is ignited by the
jet H, and the flame is by the motion of the slide conveyed to the port C, the slide
cover L being made to close the outer opening of D³ before its inner opening com-
municates with C, as shown at Fig 11. The gas passage G communicates with the
air passage D' through a number of small openings, as shown at Fig. 13, so that the
gas in issuing in small divided jets into D' becomes mingled with the air, producing
a combustible mixture. The opening of the escape valve F at the commencement
of the second in stroke of the piston (when the slide crank is at the point 4 of
Fig. 9) is cffected by a bell crank lever I, connected at one end to the stem of the
valve, and having at the other end a roller F*, acted on by a cam F³ on the shaft
K. E is the pipe for conducting away the products of combustion. The governor
Qis driven by bevil gearing Q from the shaft K, its aring move a sliding collar
Qup or down, and this collar by a bell crank lever Q1 moves the cam R longitudi-
nally. The cylinder A is by preference provided with a jacket through which
cold water is made to circulate to take off any excess of heat. The engine may
be made double acting, by providing the requisite valve gear for each end of the
cylinder the front end of which would be closed; it may be arranged in a vertical
or inclined position, and two or more engines may be connected to one crank
shaft.
Having thus described the nature of the said Invention and in what manner the
same is to be performed, as communicated to me by my foreign correspondent, it is
claimed in respect of gas motor engines:-
First. Admitting to the cylinder a mixture of combustible gas or vapour with air
separate from a charge of air or incombustible gas so that the development of heat
and the expansion or increase of pressure produced by the combustion are rendered
gradual, substantially as and for the purposes herein set forth.
Second. Compressing by one in stroke of the piston a charge of combustible and
incombustible fluid drawn into the cylinder by its previous out stroke, so that
the compressed charge when ignited propels the piston during the next out stroke, and
the products of combustion are expelled by the next in stroke of the piston, substan-
tially as herein described.
Third. Regulating the admission of the combustible gas or vapour to the
cylinder by means of a separate slide controlled by a governor, so that when the
speed of the engine increases the combustible charge is reduced, substantially as
herein described.
Fourth. The construction substantially as herein described in reference to Figs.
2 to 13 of the drawings of a gas motor engine wherein by one out stroke of the piston
separate charges of combustible fluid and air are drawn into the cylinder, which
charges are compressed by the in stroke and then ignited so as to propel the piston,
which by its return stroke expels the products of combustion.
In witness whereof, I, the said Charles Denton Abel, have hereunto set my
hand and scal, this First day of November, in the year of our Lord One
thousand eight hundred and seventy-six.
CHAS. D. ABEL. (1.S.)