Improvements in and in the Methods of Operating Gas Engines.
Year: 1889

page_text: Date of Application, 6th Aug., 1889-Accepted, 31st May., 1890
COMPLETE SPECIFICATION.
Improvements in and in the Methods of Operating Gas Engines.
I HENRY HOELLJES, of 2116 Madison Avenue, New York City, United States of
America, Lawyer do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in and
by the following statement, reference is to be had to the accompanying drawings,
forming a part of this Specification in which similar letters of reference indicate
corresponding parts in all the views:-
Figures 1, 2 3 and 4 are horizontal sections of the cylinders and valves of my
improved gas engine, type A, showing the parts in the different positions required to
perform one cycle of operations;
Figure 5 is a plan view;
Figure 6 is a vertical transverse section, taken on the line cc in Figare 1;
Figure 7 is a detail view of the lever for operating the slide valve controlling the
supply to, and exhaust from, the power cylinder;
Figures 8 and 9 are horizontal sections of the cylinders and valves of type B of
my improved engine, showing the valves and pistons in different positions ;
Figure 10 is a transverse section, taken on line y-y in Figure 9;
Figures 11 and 12 are diagrams illustrating the relation of the power cranks and
the valve operating eccentrics;
Figure 13 is an inverted plan view of the slide valves of type B shown in Figures 8
and 9, showing the devices for operating the igniting valves; and
Figure 14 is a longitudinal section of a cylinder and valve chest of a different form
of gas engine, which I have designated as type C.
In gas engines as commonly constructed, either an explosive mixture of compressed
gas and air is introduced into the cylinder, where it is ignited and exploded to propel
the piston, or separate charges, one of neutral gas, the other of an explosive mixture,
are introduced into the cylinder, the neutral gas being for the purpose of cooling tho
exploding gases, thus reducing the temperature in the engine.
As in the latter mode of operating such engines, no provisions are made to maintain
the separation of the neutral gases and the explosive mixture until the moment of
explosion, the neutral gases very rapidly intermingle with the explosive mixture, so
that instead of maintaining the heterogeneous mixture a rarefied homogeneous
mixture is formed. For this reason it is impossible to introduce large proportions of
neutral gases on account of diluting the mixture so as to render it incapable of
ignition.
In both of the types of engines to which I have referred, a very high temperature
is reached in the power cylinder, which is objectionable for two reasons; first, a large
amount of the heat of the combustion of the gases is rendered latent as the specific
heat of the gases increases with the temperature, and furthermore, at very high
temperatures a dissociation of the products of combustion takes place, which results
in the absorption of considerable heat; and second, they necessitate the absorption of
the excess of beat by means of water jackets or analogous devices. The use of water
jackets in gas engines is objectionable in many cases on account of the difficulty and
expense in securing the required amount of water for cooling the cylinders, and also
on account of the enormous loss of heat which is carried away by the water.
The object of my invention is to provide means which will admit of using lower
temperatures in gas engines, thereby avoiding the dissociation of the products of
combustion; to reduce the specific heat of the gases; to diminish the loss of heat
through the cylinder walls, and also to avoid the use of water jackets.
My invention consists in the employment of compressed air or any other suitable
gas or vapor kept separate from the explosive mixture until the combustion takes

page_text: place, the compressed air being intended to absorb the heat produced by the com-
bustion. By the absorption of the heat in this manner, the pressure of the compressed
air increases, and the difference between the original pressure and the pressure as
augmented by heat is utilized by causing the heated compressed air to propel a
piston.
To carry out my invention I compress the air, gas or vapor into the power
cylinder, or an intermediate chamber connected with the power cylinder by suitable
valves. Into the air so compressed I introduce the explosive mixture in an ignited
state, thereby raising the temperature of the compressed air, without unduly heating
the walls of the chamber or cylinder. This I effect in either of two different ways;
the first of which is to compress the explosive mixture into an intermediate chamber
adjoining the compressed air chamber and to explode the mixture when the two
chambers are thrown into communication by the opening of suitable valves, said
valves being opened automatically by the explosion of the charge or moved by con-
nection with some moving part of the engine. The second is to cause the compressed
explosive mixture to flow through gas burners, wire gauze, or tubes with small
apertures into the compressed air chambers, and igniting it when it enters said
chamber; the gas burners, wire gauze or tubes being used to prevent the flame from
running back into the explosive mixture.
I will first proceed to describe the mechanism of an engine, in which the first of
the above mentioned ways of introducing the burning gases into the compressed air,
is applied, after which I will describe the operation of the said engine.
is
Upon the frame A, are mounted two cylinders B, C, which are preferably arranged
in the same plane, the cylinder B being the power cylinder and the cylinder C the air
compressing cylinder, and between the said cylinders is arranged the valve chest D.
In the cylinder B is placed the power piston E, which is provided with a piston rod a,
passing out through a gland b, in the front end of the cylinder. In the cylinder
placed the air compressing piston F, which is provided with a piston rod c, passing
out through a gland d, in the front of the said cylinder. The piston rod a of the
power cylinder is connected with the cross-head e, sliding in suitable guides upon the
frame A, and the said cross-head is connected by a connecting rod f, with the crank g,
of the crank shaft G. In a similar manner the piston rod c of the air compressing
piston E, is connected with the cross-head, which slides in suitable guides upon the
frame A, and the said cross head is connected by a connecting rod i, with the crank,
of the crank shaft G.
In the valve chest D there are two heating chambers H, H¹, separated by the
partition k, and between said chambers and the power cylinder B there is a valve
chamber I, communicating with the chambers H, H'. The valve chamber I extends
through the entire length of the cylinder B and communicates with opposite ends of
the cylinder through ports 1, . It also communicates with the heating chambers H, H',
through ports m, m', which are opposite the ports 1, 1. At the middle of the length
of the valve chamber I, there is an exhaust opening n, for the escape of the heated air.
and the products of combustion.
In the valve chamber I, is placed a D-slide valve J, of sufficient length to
alternately establish communication between the ports 1, 1, and the exhaust opening n,
also to alternately establish communication between the heating chambers H, H³, and
opposite ends of the power cylinder B through the ports l, m, 1, m'. In Figure 1, I
have shown this valve in position to establish communication between the heating.
chamber H and one end of the cylinder B through the ports m, 1, and the chamber 1,
and also to bring the opposite end of the cylinder into communication with the
exhaust opening through the port and the cavity of the valve J. The valve J is
provided with a valve rod o, which extends through a gland p, at the front end of the
valve chest D, and is connected with valve operating mechanism which will presently.
be described.
Upon the opposite side of the heating chambers H, H₁, and between the said
chambers and the air compressing cylinder C, is arranged a valve chaunber K, which
contains the valves q, r. In the side of the valve chamber K adjoining the heating

page_text: hambers H, HI, near the opposite ends of the said valve chamber K, there are supply
ports s, s', and ignition ports t, t, adjoining the partition k. In an enlargement of
he partition and between the ports t, t', there is a cavity u, provided with a port v,
and in which is arranged an igniting burner wo.
Between the valve chamber K and the air compressing cylinder C there is a thick
partition wall L, in which are formed ports a', a³, which are opposite the ports 8, s¹,
and through which air may be forced into the heating chambers H, H, when the
ports b, c, b, c, of the valves q, r, are made to coincide with the ports a', s, and a², s¹,
respectively.
The valve
in addition to the ports 61, 62, near opposite ends thereof, is provided
with cavities, №ª, e¹, e², and ports f,; it is also provided with right-angled
passages g', g, which are oppositely arranged with respect to each other and which
establish communication between the cavities e', e, and the ports f¹. ƒ³, through
burners, arranged to discharge into the ports f¹, f. The said valve 9 is
also provided with a valve rod i, which is operated in a manner presently to be
described.
The valve is offset at opposite ends to receive the valve r, which is arranged to
embrace the offset portion of the valve q, and which is provided with a rod j', operated
in a manner also to be hereinafter described.
In the partition wall L are formed ports, ³, near the ports a', a², the said
ports, communicating with the exterior air, and being designed to supply air to
the air compressing cylinder through the cavities d', d, of the valve when the
said valve is moved so as to bring one of the said cavities opposite the puris a', k', a², k³.
In Figure 1 the cavity is shown in position to establish communication between the
ports and a so as to supply air to the cylinder while the piston F moves in the
direction indicated by the arrow.
Under the partition wall L is placed a compression cylinder M, containing a
piston N, provided with a piston rod P, which extends through a gland in the front
of the cylinder and is operated by an eccentric m², on the crank shaft G. The
cylinder M communicates at opposite ends with ports o', o' in the wall L, and in the
said wall are formed ports p', p², which are thrown into communication with
the ports o, o, by the cavities e', e, in the valve 7, and the said ports p², p², receive
air through a circular row of holes ', and gas through a central hole r, the
proportions of gas and air admitted through the said holes being such as to create an
explosive mixture in the cylinder M, so that when the piston N of the cylinder M
moves, the mixture of gas and air is taken into the cylinder through the said openings
and through the cavity of the valve g.
In the partition wall are formed chambers 0, 0₁ in which the explosive mixture
is compressed by the action of the piston N, as will be explained in the description of
the operation of the machine. The said chambers 0, 0, are provided with ports s³,,
and between the said ports in the wall L is formed a cavity t, which communicates
with the exhaust opening u².
The valve rod o is provided at its outer extremity with a fork a, in which is pivoted
a block, the said block being placed in a curved slot c³, in one arm of the sector
lover Q. The other arm of the said lever is jointed to an eccentric lever R, which is
operated by the eccentric d³, on the crank shaft G. The valve rod j' is jointed to an
eccentric rod e³, which is operated by an eccentric f³, on the crank shaft G, and the
valve rod in a similar manner is jointed to a rod g³, which is operated by an
eccentric h³, on the crank shaft G.
:
The lost motion in the slot of the sector lever Q admits of moving the valve J just
as the piston E reaches the end of its stroke. As the same movement may be
effected by means of a cam, I do not confine myself to this particular construction.
The operation of my improved gas engine is as follows:
Beginning the description of the cycle of operations with Figure 1, 1 will assuine
5 that pressure is being exerted upon the piston E, forcing it in the direction
indicated by the arrow, also that the piston F of the air compressor C is just

page_text: beginning to move in the direction indicated by the arrow, and that the piston N
of the mixture pump is beginning to make a rearward movement as indicated by
the arrow.
With the parts disposed in this manner, the valve J covers the port
and establishes communication between the exhaust end of the cylinder and the
exhaust passage n, while the said valve J allows the heated mixture contained by
the chamber H to escape through the ports m, l, into the cylinder B at the
working side of the piston E. At the same moment the ports a², k, being put
into communication through the cavity, air enters through the said ports into
the cylinder C in front of the piston F, while communication between corre-
sponding ports at the opposite end of the compressing cylinder C is closed by the
valve and the compression of the air begins in the said cylinder C.
At the same time also the port o² is put into communication with the port p
through the cavity in the valve 4, thereby allowing the explosive mixture of
gas and air to enter through the said ports into the mixture compression cylinder M,
and the charge previously drawn in and contained in the cylinder upon the opposite
side of the piston N is being compressed and forced through the port o¹, cavity el
and port into the chamber 0. At the same time the charge contained in the
chamber is liberated by the coincidence of the port 2 of the valve with the
ports, and the explosive charge contained by the said chamber in its passage
from the chamber to the chamber His ignited by the burner 2 and
exploded, so that the flame and heat resulting from the explosion enter from
the port into the charge of compressed air previously introduced into the
chamber H
At this time the port in the valve is brought into communication with the
exhaust passage t², also with the port v, and the explosive mixture is forced through
the passage by the gas compressor piston N into and through the burner h¹ into
the port, where it comes into contact with the igniting flame of the burner w;
tho
gas at the burner is ignited and the flame is then supported by the mixture
furnished through the passage g¹, until the valve g has gone so far back that the
port stands opposite the ports of the chamber 0, when the flame ignites the
charge compressed in the said chamber, the ignition of the charge occurring at the time
when the power piston is in its central position.
The condition of the engine at this stage of the operation is as follows:-The
heated mixture contained by the chamber H has been expanded into the cylinder B
and has pushed the piston nearly to the limit of its forward stroke; the chamber H¹
contains air highly heated, also a quantity of the products of combustion of the charge of
the chamber ready to be admitted to the front end of the cylinder B as soon as the
valve J is shifted. As the piston E reaches the extreme forward limit of its stroke,
the valve J is shifted by the mechanism already described, so as to throw the rear
end of the cylinder into communication with the exhaust passage n through the
port and the cavity of the valve J; and at the same time to throw the chamber H'
into communication with the forward end of the cylinder B through the ports m³, 1,
in the manner shown in Figure 2, and the piston begins its return stroke under
the pressure of the heated air and gases contained by the chamber. H'.
"
At this time the piston F will have greatly reduced the volume of air in the cylinder C, 4
and the ports b', c', of the valves 7, ", will have coincided, and the said ports will have been
brought into communication with the ports a', s, and the charge of air contained by the
said cylinder will be forced into the chamber H. The piston N also in the cylinder M
will have transferred most of the contents of the cylinder to the chamber through
the port o, cavity of the valve 9, and the port s. By the further movement of the 5
valve 9, the port in which the burner is burning, receives ignited gas and will
be brought into communication with the chambers O, H, through the ports s, t, and
the explosive mixture contained by the chamber O will be ignited and will force a jet
of flame and hot gases through the port into the body of air compressed by the
chamber H, at which time communication will be closed between the compression 5
cylinder C and the chamber H by the valves q, r, the relation of the said valves to

page_text: ach other being changed so that the ports &², c', are closed, the postero
how being as shown in Figure 3.
The condition of the engine with the parts in this position is as follows: the
products of combustion and the heated air have been driven out through the port I,
avity of the valve J and the exhaust passage n; the heated mixture contained by
he chamber H' has been expanded into the cylinder B in front of the piston E so as
have
o force the said piston nearly to the rear end of its stroke; the pistons F, N,
reversed their motion and are beginning to take in new charges, and as the piston E
is quickly moved so as to
reaches the extreme rear end of its stroke, the valve
establish cominunication between the chamber H and the space in the cylinder B
behind the piston E through ports l, m, and at the same time to bring the forward
end of the cylinder into communication with the exhaust passage through the
port and cavity of the valve J in the manner already described, when the piston E
is forced forward by the pressure of the gases contained by the chambers H, O).
It is obvious that the operation of compressing the air and gases, of igniting
charges, and of exhausting, are alike for both forward and rearward strokes of the
piston E.
.
In the modification shown in Figures 8 and 9, a thin wall L', is substituted for the
thick wall L, the chambers 0, 0, are dispensed with, and the valves q³ ³, are sub-
stituted for the valves, In other respects the engine is the same as that already
described. The valve is provided with ports, and et, and corresponding but
oppositely disposed ports 68, d³, es, at the other end; and the valve is provided
with ports e, f, g, at one end, and corresponding but oppositely disposed
ports e, f, g, at the other end. In this case the combustible mixture enters the
compressed air contained in the chambers H, H¹, through the ports t² ³ gradually in
a state of flame.
At the sides of the burner to are arranged valves *,, attached to arms, and
in
each provided with an aperture 6. The arms, js, extend under the valves 73,,
a recess in the valve casing, and are each pressed upward by a spring . On the
valves,, are formed notches, one in each valve, into which the arms j, 3, may
When only one of the notches
enter, but only when these two notches coincide.
coincides with one of the said arms the arm cannot move, as it will be retained by the
other valve.
In the sides of the chamber u are formed ports m², m³, through which communi-
cation between the inflowing jet of combustible mixture and the flame of the
burner w is established when the valves,, are opened in alternation.
In Figure 8 the piston E is being driven forward by the expansion of the heated
air and gas in the direction indicated by the arrow, while the combustible mixture is
being forced into the chamber H' from the mixture cylinder M by the piston N con-
tained in the said cylinder, the mixture passing out through the port o of the gus
compressor, the port e³ in the valve ³, through the port and through the burner h
located in the port ts. The chamber H' having been previously filled with air under
compression, and the combustible mixture having been ignited by the flame in the
burner win the manner described, and all of the ports of the said chamber being closed
with the exception of the port t, the flame issuing from the burners in the said ports
heats the compressed air to a high temperature.
While the piston N is moving forward, forcing the combustible mixture into the
compressed air, it is drawing in through the port p², the port g' of the valve ³, and
the port e of the valve ³, and the port o', a mixture of gas and air to be forced into
the chamber H after the said chamber is filled with compressed air by the return of
the piston after the port m is closed and the ports a³, s, are opened.
70%
In type B the gas inlets p', p², and the ports o', o³, lie under the valves q³,
The operation is the same for both ends of the cylinder; the difference between
type B and A is that in type B, the combustible mixture flows gradually into the
compressed air in an ignited state, whereas in the first instance the combustible
mixture is ignited and at once enters the compressed air by an explosion, the entire
heat being evolved instantaneously.

page_text: By some slight alterations of the valve arrangement and the positions of the
respective pistons I might change the action of this engine in a certain degree.
One of the modifications I might make, is to place the valve and the power
piston a quarter of a stroke forward, leaving all the other parts of the engine as
shown. This would effect that the henting chambers H, H', would be thrown into
communication with the power cylinder B, just after the air has been compressed and
before it is heated. The explosive mixture would therefore flow into the compressed
air and heat the same while the latter is moving the piston; while in the before
described case the compressed air is heated before it moves the piston.
I remark here that this alteration does not affect in the slightest degree the
principle of my invention, which remains the same in all the above described modi-
fications as well as in engines types A and C, and which consists simply in compressing
a charge of air or neutral gas into a closed chamber, and after the whole charge of
air or neutral gas has been admitted into said chamber, heating the said air or neutral
gas by introducing into it an ignited explosive mixture and finally causing the
compressed air or neutral gas and products of combustion to propel a piston.
In Figure 14 I have shown a portion of an engine in which the separation of the
air and explosive mixture is effected by a cylinder of two diameters and a corre-
sponding piston of two diameters.
On cach side of the piston E there is a cylindrical trunk or plunger * * the length
of the two plungers combined being about half that of the stroke of the piston, which
length may, however, be varied according to the particular work the engine is used
for. The plungers ³ ³ serve, in connection, with the prolongations of the main
cylinder B to keep the compressed air and explosive mixture separated until the
moment of ignition, which separation is effected by separate valves in figures 3 and 4.
When the piston E is at the end of its stroke, the respective trunk eni is close to
the bottom of the respective cylinder prolongation. During the upstroke, an explosive
mixture of gas and air enters into the cylinder B at opening, and at the same time
દી charge of compressed air is admitted into the prolongation of cylinder B at aº, the
admission of both charges being under the control of suitable valves. The slide
valves shewn comprise one valve-riding upon the other and the co-operation of both
effecting the closing and opening of the respective ports and are on a known system,
but any other suitable arrangement of valve may be substituted. Just at, or about,
the moment when the plunger 5 quits the cylinder prolongation, putting the latter in
communication with the main cylinder, the charge of explosive mixture is fired. The
air now brought in contact with the hot products of combustion, not only serves as a
cushion preventing the otherwise violent shock generated by the explosion, but also
serves to cool the hot gases, thus keeping the piston and cylinder cool.
It will be seen that by the combustion of a small charge of explosive mixture, and
forcing the flame and heated gases of the said mixture into a body of compressed air,
I am enabled to strongly heat the air without bringing the flame into contact with
the walls of the engine to any considerable extent, and therefore, I am enabled to not
only prolong the life of the engine, but also to avoid the use of cooling devices; and
further, I effect an enormous saving of fuel, as the heat is imparted directly to the
charge of compressed air, and communicated only in a small degree to the walls of
the engine.
It is immaterial whether the ignition of the explosive mixture is effected by a
flame igniter, as herein described, or by an electric spark or whether the air is
compressed in chambers as described or in the motor cylinder. It is also immaterial
whether the explosive mixture is introduced into the compressed air in a state of
flame, while, or before moving the piston, or whether the whole quantity of explosive
mixture is introduced into the compressed air instantaneously by an explosion. For
engines of type A it is also immaterial whether the explosive mixture is compressed.
It is also immaterial whether the air is compressed by the motor piston itself, or by a
separate air compressing piston, or whether the air is first compressed in the com-
pression cylinder and then admitted to the chamber to be heated, or whether it is
admitted during the entire stroke of the compression piston.

page_text: I do not limit or confine myself in my present application to any particular kına or
valve or any particular arrangement of the mechanism or of the chambers, or the gas
and air inlets, as these and all other mechanical contrivances for carrying out
my invention may be varied according to the particular use for which the engine is
designed.
By using my improved method of operating gas engines, 1 effect an important
saving in fuel.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is
1. The method of operating a gas engine, which consists in compressing a certain
charge of air or neutral gas into a heating chamber, compressing a certain charge of
explosive mixture, consisting of inflammable gas or vapor and air, igniting this
explosive mixture and causing it to enter in an ignited state into the said heating
chamber, in which the whole charge of compressed air or neutral gas is already con-
tained, thereby heating the air or neutral gas, and finally discharging the heated
compressed air or neutral gas and the products of combustion into a power cylinder,
causing them to move a piston, substantially as specified.
2. The method of heating a charge of compressed air or neutral gas, by introducing
the charge of compressed air or neutral gas into a heating chamber, and causing an
ignited explosive mixture consisting of inflammable gas or vapor and air, to enter into
said heating chamber in which the whole charge of compressed air or neutral gas is
already contained, substantially as specified.
3. The method of preventing the dilution of the explosive mixture in a gas engine,
which consists in compressing a charge of air or neutral gas into a heating chamber,
and introducing an ignited explosive mixture into said heating chamber in which
the whole charge of compressed air or neutral gas is already contained, substantially
as specified.
4. The method of operating a gas engine, which consists in compressing a certain
quantity of air or neutral gas into a heating chamber or the motor cylinder, intro-
ducing an explosive mixture into another chamber or the motor cylinder, separated
from the body of the compressed air or neutral gas by the motor piston, establishing a
communication between the compressed air or neutral gas and the explosive mixture
by moving the motor piston, in the meantime igniting the whole charge of said
explosive mixture instantaneously, the exploding gases heating the body of the com-
pressed air or neutral gas; and finally causing the so heated compressed air or neutral
gas and products of combustion to move a piston, substantially as specified.
5. The method of operating a gas engine, which consists in compressing a certain
quantity of air or neutral gas into a heating chamber or the motor cylinder, intro-
ducing an explosive mixture into a chamber separated from the body of the com-
pressed air or neutral gas, igniting the whole charge of said explosive mixture
instantaneously and causing the exploding gases to enter through automatic valves, or
valves moved by the engine, into the body of the compressed air or neutral gas,
thereby heating the same, and finally causing the so heated compressed air or neutral
gas and products of combustion to move a piston, substantially as specified.
6. The method of operating a gas engine, which consists in compressing a certain
quantity of air or neutral gas into a heating chamber, causing a compressed charge of
explosive mixture to flow in a state of flame gradually into the chamber in which the
whole charge of compressed air or neutral gas is contained, then heating the body of
0 compressed air or neutral gas; the quantity of which latter being constant and not
augmented while being heated, except by the products of combustion of the explosive
mixture, and finally, after the complete combustion of the explosive charge dis-
charging the heated compressed air or neutral gas and products of combustion into a
power cylinder, causing it to move a piston, substantially as specified.
5 7. The method of operating a gas engine, which consists in compressing a certain
quantity of air or neutral gas into a heating chamber or the motor cylinder, causing a

page_text: compressed charge of explosive mixture to flow in a jet gradually into the chamber or
motor cylinder, in which the whole charge of air or neutral gas is contained; said jet
of explosive mixture being ignited when flowing into and thus heating the body of
the compressed air or neutral gas, the quantity of which latter being constant and not
augmented while being heated, except by the products of combustion of the explosive
mixture, the compressed air or neutral gas and products of combustion being caused
to move a piston while the explosive mixture flows into the compressed air or neutral
gas and heats the same, substantially as specified.
8. The method of using heating chambers, communicating with the motor cylinder
by suitable valves, into which heating chambers charges of compressed air or neutral
gas and charges of an ignited explosive mixture are introduced intermittingly and
successively to each other, each charge of air being first admitted and then being
heated by a charge of an ignited explosive mixture, the so heated air or neutral gas
and the products of combustion then being discharged into the power cylinder to
move a piston, substantially as specified.
Dated this 6th day of August 1900
H. HOELLJES.
By A. M. & Wm. Clark,
53, Chancery Lane, London, Patent Agents.