IMPROVEMENTS IN ENGINES WORKED BY THE COMBUSTION OF GASEOUS FUEL
Year: 1881

page_text: LETTERS PATENT to Charles William Siemens, of No. 12, Queen Anno's Gate,
Westminster, in the County of Middlesex, for an Invention of "IMPROVEMENTS
IN ENGINES WORKED BY THE COMBUSTION OF GASEOUS FUEL."
PROVISIONAL SPECIFICATION left by the said Charles William Siemens
at the Office of the Commissioners of Patents on the 7th December 1881.
CHARLES WILLIAM SIEMENS, of No. 12, Queen Anne's Gate, Westminster, in the
County of Middlesex. "IMPROVEMENTS IN ENGINES WORKED BY THE COMBUS-
TION OF GASEOUS FUEL."
In a Provisional Specification filed by me on the 9th June, 1881, No. 250+, I
described a form of gas motor engine in which a shielded differential piston forces
by its downstroke a combustible mixture of gas and air into a receptacle, whilst a
charge of the mixture from the receptacle enters the cylinder above the piston,
and is ignited and burns therein, expanding in one volume. My presont Invention
relates to means of ensuring the ignition of the gaseous charge, particularly when
a mixture of low combustibility is employed, and to a modified form of engine in
which, instead of a gaseous combustible mixture, air is employed either with a
slight admixture of combustible gas or without such admixture.
For the purpose of ensuring ignition of the gaseous mixture entering the
cylinder, I cause a portion of the entering charge to become enriched by the
addition to it of combustible gas or vapour unmixed or partially unmixed with air,
so that this portion of the charge is readily ignited, and communicates ignition to
the rest of the charge, which is less rich in combustible matter. According to one
method I provide a cock or revolving slide moving in time with the engine shaft.
A cavity in this cock or slide at one part of its revolution receives a supply of
combusti le hydro arbon liquid, preferably of a volatile kind, from a supply vessel
connected to the cock or slide by a pipe. At another part of the revolution of the
cock or slide, that is to say, at the time when the charge begins to enter the
cylinder, the liquid contained in the cavity is presented to a current of a portion of
the gas-ous mixture or air on its way to the cylinder, and mixes therewith
en riching it, and this enriched current then passing electrodes furnishing a spark
ED
J1

page_text: or a platinum wire rendered incandescent by an electrical current becomes ignited,
and ignites the remainder of the charge, which passes separately into the cylinder,
heated by its passage through the regenerator. According to another method I
work from the piston of the engine the plunger of the pump, which forces com-
bustible gas unmixed with air into a receptacle. A portion of this gas is caused to
enter the cylinder along with a portion of the mixture of gas and air, enriching it,
so that it is ignited as above described. The gas pump has its suction and delivery
governed by the same revolving slide as that which governs the supply and
discharge of the engine, and the passage of gas from the receptacle of the pump to
join the current of gaseous mixture entering the cylinder is governed by &
valve which is opened by the pressure of the entering current acting in opposition
to a spring on a piston connected to the stem of the gas valve.
In the modified forms of engine, according to my present Invention, heat is
imparted to the currents entering the cylinder by a regenerator supplemented by
jets of combustible gas or vapour, which may be previously heated, and which
intermingle within the cylinder with the current of compressed air heated by its
passage through the regenerator; or, according to another arrangement, the
compressed air on issuing from the regenerator is farther heated by one or more
jet furnaces of the following kind -I provide in the upper part of the cylinder a
deep cup projecting down into the cylinder, and in this cup I burn a gas flame,
supplying the gas by a central pipe, and the air for combustion by a larger pipe
surrounding it, which preferably has fins or ribs exposing large surface. The
products of combustion ascend an outer pipe, heating the air pipe on their way to
a chimney. Surrounding the cup, and supported on a grating made in one piece
with the cup, which is preferably made of copper or other well conducting metal,
is arranged an annular regenerator, the lower part of which is thus heated by
conduction.
The engine operates as follows:-
The annular piston in its up stroke draws in air alone, which in its downstroko
it delivers into the receptacle. A charge of air from the receptacle is admitted to
the top of the cylinder, and entering it through the regenerator is heated in its
passage, and becomes still farther heated by contact with the heated cup, thus
expanding in volume and propelling the piston downwards. By the upstroke of
the piston the air which had performed work is expelled through the regenerator,
giving up in its passage a large portion of its heat, which is available for heating
the succeeding charge of air entering the cylinder through the regenerator. The
air thus discharged operates as a blast in the chimney, thus causing a draught, by
which the combustion in the cup is rendered more active. For engines of small
size a single cup with its gas and air supply pipes suffices, but when the cylinder
of the engine is of considerablo size, instead of a single cup with its adjuncts, I
prefer to employ several cups, thus subdividing and enlarging the heating surface.
Although I have described the cylinder as being vertical, with the combustion at
its upper end, it might obviously be arranged in other attitudes, and several such
cylinders may be arranged to work together on one shaft, in which case the chimney
blast is rendered more continuous.
In starting the engine I admit a small quantity of water into the passage leading
to the cool side of the regenerator, and this in passing with the air through the
regenerator becomes converted into steam, which aids in starting the engino. Such
conjoint action of heated air and steam may be continued during the working of
the engine by injecting spray into the pumping part of the cylinder, which serves
to keep it cool, and joining with the compressed air enters the cylinder through
the regenerator becoming converted into steam.
The arrangements which I have described for heating the cylinder charge in
and after its passage through the regenerator are obviously applicable in engines
of other forms.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Charles William Siemens in the Great Seal Patent Office on the
7th June 1882.
CHARLES WILLIAM SIEMENS, of 12, Queen Anne's Gate, Westminster, in
the County of Middlesex. "IMPROVEMENTS IN ENGINES WORKED BY THE
COMBUSTION OF GASEOUS FUEL."
In the Specification of a Patent granted to me on the 9th June 1881, No. 2504,
I described a form of gas motor engine in which a shielded differential piston
forces by its downstroke a. combustible mixture of gas and air into a receptacle,
whilst a charge of the mixture from the receptacle enters the cylinder above the
piston and is ignited and burns therein, expanding in volume. My present Inven-
tion relates to means of ensuring the ignition of the gaseous charge, particularly
when a mixture of low combustibility is employed, and to a modified form of
engine in which instead of a gaseous combustible mixture air is employed either
with a slight admixture of combustible gas or water vapour, or without such
admixture.
For the purpose of ensuring ignition of the gaseous mixture entering the
cylinder, I cause a portion of the entering charge to become enriched by the
addition to it of combustible gas or vapour unmixed or partially unmixed with
nir, so that this portion of the charge is readily ignited, and communicates ignition
to the rest of the charge which is less rich in combustible matter. According to
one method I provide a cock or revolving slide moving in time with the engino
shaft, a cavity in this cock or slide at one part of its revolution receives a supply
of combustible hydrocarbon liquid, preferably of a volatile kind, from a supply
vessel connected to the cock or slide by a pipe. At another part of the revolution
of the cock or slide, that is to say, at the time when the charge begins to enter the
cylinder, the liquid contained in the cavity is presented to a current of a portion
of the gaseous mixture or air on its way to the cylinder and mixes therewith,
enriching it, and this enriched current then passing electrodes furnishing a spark or
a platinum wire rendered incandescent by an electrical current becomes ignited,
and ignites the remainder of the charge which passes separately into the cylinder
heated by its passage through the regenerator.
Fig. 1 of the accompanying Drawings is an elevation partly in section of the
upper part of the cylinder of an engine of the kind described with reference to
Figs. 1 and 2 of the Drawings annexed to the Specification, No. 250+ of 1881,
above referred to, with provision for securing ignition of the gaseous mixture when
the gas employed is of poor quality, or when it is diluted with a large proportion
of air.
L is a vessel containing a supply of hydrocarbon oil, preferably of volatile
character; from this vessel pipes lead to two cocks l, one for each cylinder, these
cocks being caused to revolve in time with the engine shaft by a chain M com-
municating motion from a chain wheel on the engine shaft to a chain wheel of
equal size on the spindle of the two cocks. The plug of each cock has on its side
a small hollow, which during one part of its revolution presents itself under the
oil pipe and receives a charge of oil; during another part of its revolution, which
is timed to correspond with the flow of gaseous mixture to the cylinder, the hollow
of the plug presents itself to the bend of a pipe leading from the top of the
cylinder to a port p opening in the cylinder below the regenerator R, in which
port are situated two wires of platinum P. These wires are connected with the
brushes of a commutator on the engine shaft, which commutator is in electrical

page_text: connection with the poles of a battery, dynamo-electric machine, or other source of
electricity. Instead of two wires to produce a spark, a single wire may be
arranged to be kept incandescent, or to become incandescent at the proper time
for ignition.
According to another method, I work from the piston of the engine the plunger
of a pump, which forces combustible gas unmixed with air into a receptacle; a
portion of this gas is caused to enter the cylinder along with a portion of the
mixture of gas and air, enriching it, so that it is ignited as above described. The
gas pump may have its suction and delivery governed by the same revolving slide
as that which governs the supply and discharge of the engine, and the passage of
gas from the receptacle of the pump to join the current of gaseous mixture entering
the cylinder is governed by a valve which is opened by the pressure of the entering
current acting in opposition to a spring on a piston connected to the stem of the
gas valve.
As according to the construction described in the Specification, No. 2504 of 1881,
above referred to, each cylinder of the engine is single acting, it is convenient to
have for such a purpose as a marine ongine more than two cylinders in connected
operation so as to avoid dead centres. Fig. 2 is a vertical section partly through
one cylinder and partly through the revolving valve, and Fig. 3 is a plan partly in
section of an engine having four cylinders working on one shaft, each pair working
at right angles a crank opposite to the crank worked by the other pair. To the
piston of each cylinder is attached the plunger of a small compressing pump S,
which communicates by a pipe with a cavity 8 in the valve case, shown to an
enlarged scale in vertical section at Fig. 4, and in sectional plan on Z, 2, 2, Z, at
Fig. 5, and on Z, y, y, Z, at Fig. 6. This cavity also communicates by pipes s', 8',
with the gas supply, and by means of pipes 82, 8², with a valve box. The revolving
slide G is provided with annular ports or cavities facing the cavity 8, so arranged
that at each upstroke of the plunger of S, gas supplied by the pipes s¹, s², is drawn
into the pump, and at each down stroke this gas is discharged into the pipes 5², ³,
which are connected by a pipe forming with them a reservoir containing the gas
under pressure. In the valve box T there is a piston kept down by an adjustable
spring, the stem of the piston closing as a valve the mouth of the pipe &². To the
space under the piston a pipe t leads from the top of the cylinder above the
regenerator R, and a passage in which are situated the platinum wires P leads
from the same space to the cylinder under the regenerator. When by the action
of the revolving valve G, as already described, the gaseous mixture is admitted to
the top of the cylinder above the regenerator, the pressure communicated by the
pipe acting on the piston in the valve box T raises that piston and so opens the
pipe & thereupon gas issuing from the pipe 8ª and mingling with the gas and air
supplied by the pipe flows through the passage past the platinum wires P, and
these give at this time a spark which ignites the gaseous mixture passing them,
and this in its turn ignites the charge entering the cylinder through the
regenerator.
In the modified forms of engine, according to my present Invention, heat is
imparted to the currents entering the cylinder by a regenerator supplemented by
jets of combustible gas or vapour which may be previously heated, and which
intermingle within the cylinder with the current of compressed air heated by its
passage through the regenerator. This may be effected in an engine of the kind
described with reference to Figs. 2, 3, 4, 5, and 6, air alone being admitted through
the regenerator and a combustible gaseous mixture being passed through the
ignition port, of which, when this mode of operating is adopted, there may be
several forming jets around the cylinder. Or according to another arrangement,
the compressed air on issuing from the regenerator is farther heated by one or
more jet furnaces of the following kind:-I provide in the upper part of the
cylinder a deep cup projecting down into the cylinder, and in this cup I burn a gas
flame, supplying the gas by a central pipe, and the air for combustion by a larger
pipe surrounding it, which preferably has fins or ribs exposing large surface for

page_text: radiation and conduction. The products of combustion ascend an outer pipe
heating the air supply pipe on their way to a chimney. Surrounding the cup and
supported on a grating made in one piece with the cup, which is preferably mado
of copper or other well conducting metal, is arranged an annular regenerator, the
lower part of which is thus heated by conduction. The engine operates as
follows: The annular piston in its upstroke draws in air alone, which in its down-
stroke it delivers into the receptacle. A charge of air from the receptacle is
admitted to the top of the cylinder, and entering it through the regenerator is
heated in its passage, and becomes still farther heated by contact with the heated
cup, thus expanding in volume and propelling the piston downwards. By the
upstroke of the piston the air which had performed work is expelled through the
regenerator, giving up in its passage a large portion of its heat, which is availablo
for heating the succeeding charge of air entering the cylinder through the
regenerator. The air thus discharged operates as a blast in the chimney, thus
causing a draught, by which the combustion in the cup is rendered moro activo.
For engines of small size a single cup with its gas and air supply pipes suffices, but
when the cylinder of the engine is of considerable size, instead of a single cup with
its adjuncts, I prefer to employ several cups, thus subdividing and enlarging the
heating surface.
Fig. 7 is a vertical section of an engine, in the cylinder of which a single heating
cup is employed. The lower part A of the cylinder is kept cool by circulation of
water through a casing surrounding it; the upper part B is lined with refractory
material, and the piston C which has a shield of refractory material hollowed out
in the middle is linked by the connecting rod D to the crank on the shaft. The
shaft by bevil wheels works the rotating slide G, which has its passages
arranged in relation to the cylinder ports, as described with reference to Fig. 1 of
the Drawings annexed to the Specification, No. 2504 of 1881 above referred to, so
that during the ascent of the piston C, the cold air supply is drawn into the
annular space A below the piston, whilst the exhaust air is discharged from above
the piston through the regenerator R and the exhaust pipe p, and during the
descent of the piston the air from below it is sent through the hollow of the
slide G, and through the regenerator R into the upper part of the cylinder, being
partly heated by passing through the regenerator, and farther heated by contact
with the heated cup H. The regenerator as above described rests on a grating h
projecting from and made in one piece with the cup H, so that heat is freely con-
ducted to the lower part and side of the regenerator which annularly surrounds the
cup. The heating of the cup is effected by an ignited jet of gas issuing from the
pipe K supplied with air descending the pipe L. The products of combustion
ascend outside the pipe L and pass by the branch M to the chimney pipe N. Tho
exhaust from the cylinder issuing by the pipe p acts as an ejector promoting the
flow of the air and the products of combustion, as indicated by the arrows. Fig. 8
is a vertical section, and Fig. 9 a plan shewing the upper part of a cylinder with
three heating cups heated by Bunsen burners. In order to utilise to a great extent
the heat of the products of combustion, I provide fins or ribs V projecting radially
inside and outside the air pipes L, so as to abstract heat from the ascending
products of combustion, and impart heat to the air descending around the tubes of
the Bunsen burners.
Although I have described the cylinder as being vertical with the combustion at
its upper end, it might obviously be arranged in other attitudes. And several such
cylinders may be arranged to work together on one shaft, in which case the
chimney blast is rendered more continuous.
In starting the engine I admit a small quantity of water into the passage leading
to the cool side of the regenerator, and this in passing with the air through the
regenerator becomes converted into steam which aids in starting the engine. Such
conjoint action of heated air and steam may be continued during the working of
the engine by injecting spray into the pumping part of the cylinder, which serves

page_text: to keep it cool, and joining with the compressed air enters the cylinder through
the regenerator, becoming converted into steam.
The arrangements which I have described for heating the cylinder charge in and
after its passage through the regenerator are obviously applicable in engines of
other forms.
In engines having henting cups and regenerators, as described with reference to
Figs. 7, 8, and 9, instead of admitting air alone to the cylinder, a portion of com-
bustible gas may be mixed therewith, the mixture being heated by passing through
the regenerator, and ignited by contact with the heated cup. Or the combustible
gas may be admitted in jets separate from the air that passes through the regene-
rator, the mixture of the gas and heated air being ignited within the cylinder by
contact with the heated cup, without requiring special igniting arrangements.
Having thus described the nature of my Invention, and in what manner the
same is to be performed, 1 claim,—
First. For ignition of the gaseous mixture admitted to the cylinder, the use of
apparatus whereby a portion of the entering charge is enriched by the addition of
combustible gas or vapour, substantially as herein described with reference to
Fig. 1 of the accompanying Drawings.
Second. The arrangement and construction of engine, substantially as described
with reference to Figs. 2, 3, 4, 5, and G.
Third. Heating the charge in the cylinder by passing the main and incom-
bustible portion of the charge through a regenerator, and farther heating it by
ignited jets within the cylinder, substantially as herein described.
Fourth. Heating the charge in the cylinder by passing it through a regenerator,
and farther heating it by contact with a cup or cups heated by external flame,
substantially as herein described.
•
Fifth. The combination of the henting cup referred to in the preceding claim,
with an annular regenerator surrounding the cup, and resting on a grating in
intimate metallic connection with the cup, substantially as and for the purposes
herein set forth.
Sixth. Providing the passages to and from the heating cup with metallic ribs for
conduction and transfer of heat, substantially as herein described.
In witness whereof, I, the said Charles William Siemens, have hereunto set
my hand and seal, this Seventh day of June, in the year of our Lord
One thousand eight hundred and eighty two.
2 117 SIEMENS