IMPROVEMENTS IN CALORIC ENGINES WHEREIN THE WORKING FLUID IS HEATED BY INTERNAL COMBUS- TION OF GAS OR OTHER FUEL."
Year: 1881

page_text: LETTERS PATENT to Matthew Piers Watt Boulton, of Tew Park, in the
County of Oxford, for an Invention of "IMPROVEMENTS IN CALORIC
ENGINES WHEREIN THE WORKING FLUID IS HEATED BY INTERNAL COMBUS-
TION OF GAS OR OTHER FUEL."
PROVISIONAL SPECIFICATION left by the said Matthew Piers Watt
Boulton at the Office of the Commissioners of Patents on the 29th March
1881.
MATTHEW PIERS WATT BOULTON, of Tew Park, in the County of Oxford.
"IMPROVEMENTS IN CALORIC ENGINES WHEREIN THE WORKING FLUID IS HEATED
BY INTERNAL COMBUSTION OF GAS OR OTHER FUEL."
In the Specification to Letters Patent granted to me on the 7th February 1879,
No. 495, and in a Provisional Specification filed by me on the 17th December 1880,
No. 5270, I described the construction and operation of a caloric engine in which
successive charges of cold air or elastic fluid received in a charging vessel were by
the movements therein of a displacer passed through a separate heating vessel back
to the charging vessel, whence they expanded in a cylinder performing work.
My Invention relates to a construction and arrangement in which the separate
heating vessel is dispensed with by employing the internal combustion of gaseous
or liquid fuel. The following main parts of the engine remain the same, that is to
say:-
(1.) A cylinder fitted with a piston which drives the engine, which piston is
furnished with a shield, or inay be so.
(2.) A chamber within which works a piston furnished by preference with a shield,
which by its movements takes in charges of cold air, transfers them from the cold
to the hot end of the chamber, and expels a portion of the exhaust. I term this
chamber the air charging chamber, and its piston the displacer, or the main displacer,
as the fluid pressure on both its sides is equal or nearly so.
(3.) A regenerator, or in some cases more than one regenerator.
In addition to these I provide means for introducing charges of the gas or other

page_text: fuel. This may be done by an ordinary pump, but it may be done by a charging
chamber with displacer similar to that employed for introducing the charges
of air.
The combustion takes place within the air-charging chamber, or a space connected
with it.
I use these parts to a certain extent in the way which I described in my previous
Specifications above referred to, that is to say, I cause the displacer to make two
strokes for preparing the charge of hot air, which is to expand in the cylinder and
perform work therein, which two strokes take place while the piston which drives
the engine is making its discharge stroke. While the hot air is expanding in the
cylinder, urging the piston on its working stroke, the displacer is stationary or
nearly so.
But though my present mode of operating so far resembles my former one it
differs in several respects, owing or partly owing to the difference in the manner of
effecting the combustion.
For describing the course of operations I shall first take the case where gas, is
the fuel employed. Before entering more into detail I would observe in the first
place that the air taken into the air-charging chamber is not all intended for
combustion. A portion of it only is burnt with the gas, the remainder is heatedby
the combustion.
By suitably proportioning the capacities of the air-charging chamber and the gas
pump or gas charge, the temperature of the hot working air is made such as is
desired. If this is made high then the piston which drives the engine is furnished
with a shield, but a temperature may be used so moderate that this is not
necessary, and this is convenient if it is desired that the engine should be double
acting.
In my first description I shall suppose as being the simplest case that the gas is
introduced by means of an ordinary pump injecting it against the pressure within
the chamber where it is burnt. I may observe that in my description I shall
frequently use the term "air" to signify elastic fluid generally.
For convenience of description I shall suppose that the upper end of the air
charging chamber is the cool end, the lower one the hot end, and I shall suppose
that the working stroke of the piston is upward, its discharge stroke downward.
I shall take for the starting point the time when the piston is ready to begin its
discharge stroke. At this time the displacer is at the upper or cool end of its
chamber, the space beneath it being full of exhaust air still retaining considerable
heat.
The piston is at the top of its cylinder, the space beneath it similarly full of
exhaust air.
Communication is open between all the spaces filled with exhaust air.
I may observe that by exhaust air I mean generally air which has discharged its
office of performing work in the cylinder, as described. It may in some cases pass
off to perform work elsewhere.
The displaces moves downwards. Above it draws in or is followed by the supply
of atmospheric air; below it expels exhaust through the regenerator, and out by
the main eduction valve.
The piston also moves downwards, expelling exhaust in like manner through the
regenerator and main eduction valve." This state of things continues till the
displacer has completed its down stroke, at which time the piston is about mid-way
in its discharge stroke.
Communication is now closed between the cylinder and the other parts of the
engine. The secondary eduction valve connected directly with the cylinder is
opened.
The displacer now ascends, displacing the atmospheric air above it. It causes
this to pass through the regenerator into the hot space beneath the displacer.
While this is taking place the gas pump makes its stroke, injecting gas, which
mingles with a portion of the air entering the hot space, as previously described, is

page_text: ignited and undergoes combustion, which takes place gradually. This combustion
heats the other portion of the entering air.
While the displacer is making its up-stroke, as previously described, the piston
completes its discharge stroke, expelling exhaust through the secondary eduction
valve.
When the strokes above described are completed the space beneath the displacer
is filled with hot air ready for performance of work.
The proper changes of valves having been made communication is now opened
between the cylinder and the other parts of the engine, and the hot air expands in
the cylinder, urging the piston which performs its working stroke.
While it is making this the displacer remains at the upper or cool end of its
chamber, stationary or nearly so. The working stroke having been completed,
and the proper changes of valves made, the point previously taken as starting point
is reached.
In the above described manner of operating the gas pump injects its charge of
gas against the pressure in the displacing chamber, which rises as the displacer
ascends; but as the quantity of gas relatively to the total quantity of working
fluid is small, the power needed to work the gas pump is not very considerable.
Instead however of using a gas pump a gas charging chamber and displacer,
with regenerator or passage, may be employed for the purpose of introducing the
gas supply, and sending it to mix with the air in the hot space. In this case when
the gas displacer displaces the gas above it, or in its cool side, it sends the gas
through the gas regenerator or passage into the space where combustion is effected,
as previously described, while air or fluid from the hot space beneath the main
displacer enters below the gas displacer or on its hot side.
Such a second charging chamber instead of taking in gas alone may take in
gas and air mixed in incombustible proportion.
For the mixing of the gas and air for the purpose of combustion any known
suitable form of mixer or burner may be employed in any convenient position
between the regenerator and the hot end of the air charging chamber.
In the method of operating above described the combustion takes place gradually,
but another method may be employed. The gas is introduced into the hot space
only during the first portion of the main displacer's stroke. It it not ignited as it
enters, but it mixes with the air which enters the hot space as it is displaced by
the main displacer, so as to form a combustible mixture beneath the main displacer.
The proper quantity of this having been introduced, the stroke of the gas pump
or gas displacer finishes, and about the same time ignition is effected. The main
displacer in the meanwhile is continuing its upward movement, and in doing so it
transfers air from the cool space above it to the hot space below through the.
regenerator, this air taking up the heat which the expansion of the ignited mixture
through the regenerator had previously imparted to it.
The general construction above described remaining the same, one eduction valve
only may be employed and the exhaust be discharged through this and not
through the regenerator.
In the methods previously described only one regenerator was used to utilise
the heat of the exhaust, and a certain portion of the exhaust was discharged
without passing through the regenerator. But a pair of regenerators may be
employed, and in this case the whole exhaust may be passed through each
regenerator alternately.
Passages are provided governed by valves, so that each regenerator can when
desired be placed either in or out of communication with the air charging chamber,
the cylinder, and the eduction port. During each discharge stroke of the piston
the whole exhaust is sent through one of the regenerators, a portion of it by the
displacer, the remainder by the piston. When the displacer has finished its down-
stroke, or that which expels exhaust, communication is cut off between it and the
regenerator through which it just expelled exhaust, and is opened between it and
the other regenerator. When it ascends it transfers its charge of air to the hot

page_text: side through this regenerator while the piston continues expelling exhaust through
the other regenerator.
During the next discharge stroke the function of the two regenerators is reversed;
each performs the part which the other performed in the preceding stroke. Thus
whenever the displacer transfers its charge from the cold to the hot end of its
vessel, it sends it through that regenerator which in the previous discharge stroke
was heated by passage through it of exhaust.
In the above description I have supposed gas to be the fuel employed, but the
matter employed as fuel may be varied. A liquid whose vapour is inflammable,
such as various hydrocarbons, and many other liquids may be employed to generate
inflammable vapour in any known suitable apparatus at regulated pressure, and a
definite quantity of this vapour may be supplied to the engine and act like gas as
above described; or a certain portion of the vapour may be admitted by means
of a valve allowing it to flow a certain time from a vessel of regulated pressure
as may also be done in the case of the gas.
Again, liquid such as above mentioned may be injected directly into the hot
chamber, so as to be vaporised by the heat within it and undergo combustion
along with the air.
In such a case the liquid may be injected in numerous fine streams, or in such a
manner as to form fine spray, which is dispersed by the air and undergoes
combustion.
When gas is employed as the material for combustion, it may be supplied to the
engine in regulated quantity from a reservoir in which it is stored at any pressure
and in any quantity desired. Such a mode of supplying gas to the engine is more
especially applicable for purposes of locomotion.
Also both the gas and air supplied to the engine may be compressed in vessels
at high pressure and may work within the engine at high pressure. This method
again, is applicable for purposes of locomotion. Compressed air is now employed
in some cases to work locomotive engines; if the same amount of elastic fluid is
compressed as gas and air it would effect locomotion to much greater distances on
account of the generation of heat. The gas and air issuing from the reservoirs
should be delivered to the engine at regulated pressure, as previously noticed.
When the gas and air thus work at high pressure the elastic fluid which is
discharged from the apparatus above described after performance of work in it is
discharged at high pressure, and is still capable of performing work. For this
purpose it is employed in a second cylinder or in successive cylinders, as steam is in
a compound steam engine.
In carrying out the operations above described, ignition may be effected by
means of any suitable known apparatus. One which may be employed is that
which I described in the Specification of a Patent granted to me on the 19th June
1868, No. 1988, where ignition is effected by the movement of a lamp. But I
improve this form by making the upper part, or the terminal part which enters the
vessel where the mixture is to be ignited to seat itself as a valve when the lamp is
withdrawn.
The following is another construction which may be employed :-
A flame as of a gas jet or lamp burns within or partially within a passage close
to the igniting port. This passage has two apertures, one for ingress of air and
the other for egress of the flame or the products of combustion.
Outside the latter
aperture a flame is kept constantly burning. Within the passage is fitted a slide
which, when ignition is about to be effected, is moved by the engine so as to cover
both the apertures. The stem of this slide when it is moved, raises in the last part
of its stroke a check valve which covers the igniting port, thus opening the ignition
passage to the chamber containing the inflammable mixture.
In cases where this mixture is at a pressure higher than that of the atmosphere,
a small secondary check valve may be fitted on the main check valve. This
secondary valve being first opened by the stem of the slide, permits passage of fluid

page_text: along a groove or cavity in the stem, so as to establish equilibrium in the ignition
passage, immediately after which the larger check valve opens.
After the ignition the slide is retracted, permitting the check valve or valves to
close, and re-opening the apertures of the ignition passage, and the igniting flame
if it should have been extinguished is relighted by the external flame; things are
then ready for repeating the operation.
The movement of the slide may also at its commencement open a valve in the
gas pipe, so as to give a momentary increase to the lighting flame.
The movement of the slide may also change the direction of the igniting jet, so
as to direct it against or towards the igniting port.
In the previous account I described a construction of engine in which the gas and
air were delivered to the engine at high pressure from vessels in which they were
stored. It is evident that the compression of the gas and air might be effected by
means of pumps worked by the engine, the construction of this remaining in other
respects the same.
In the construction of engine which I previously described, in which the gas and
air are burnt gradually, the general construction remaining the same, the regenerator
may be dispensed with, the exhaust passing away directly through the eduction
valve. In such a case one eduction valve suffices.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Matthew Piers Watt Boulton in the Great Seal Patent Office on
the 23rd September 1881.
MATTHEW PIERS WATT BOULTON, of Tew Park, in the County of Oxford.
"IMPROVEMENTS IN CALORIC ENGINES WHEREIN THE WORKING FLUID IS HEATED
BY INTERNAL COMBUSTION OF GAS OR OTHER FUEL."
In the Specification to Letters Patent granted to me on the 7th February 1879,
No. 495, and in the Specification to my Patent dated the 17th December 1880,
No. 5270, I described the construction and operation of a caloric engine, in which
successive charges of cold air or elastic fluid received in a charging vessel were, by
the movements therein of a displacer, passed through a separate heating vessel back
to the charging vessel, whence they expanded in a cylinder performing work.
My present Invention relates to a construction and arrangement in which the
separate heating vessel is dispensed with by employing the internal combustion of
gaseous or liquid fuel. The following main parts of the engine remain the same,
that is to say :-
(1.) A cylinder fitted with a piston which drives the engine, which piston is
furnished with a shield, or may be so.
(2.) A chamber within which works a piston furnished by preference with a
shield, which by its movements takes in charges of cold air, transfers them from
the cold to the hot end of the chamber, and expels a portion of the exhaust. I
term this chamber the air charging chamber, and its piston the displacer (or the
main displacer) as the fluid pressure on both its sides is equal or nearly so.
(3). A regenerator, or in some case more than one regenerator.
In addition to these I provide means for introducing charges of the gas or other
fuel. This may be done by an ordinary pump; but it may be done by a charging
chamber with displacer, similar to that employed for introducing the charges
of air.
The combustion takes place within the air charging chamber, or a space con-
nected with it.
I use these parts to a certain extent in the way which I described in my
previous Specifications above referred to, that is to say, I cause the displacer to
make two strokes for preparing the charge of hot air which is to expand in the
cylinder and perform work therein, which two strokes take place while the piston
which drives the engine is making its discharge stroke. While the hot air is
expanding in the cylinder, urging the piston on its working stroke, the displacer is
stationary or nearly so.
But though my present mode of operating so far resembles my former one, it
differs in several respects, owing or partly owing to the difference in the manner of
effecting the combustion.
For describing the course of operations I shall first take the case where gas is
the fuel employed. Before entering more into detail, I would observe in the first
place that the air taken into the air-charging chamber is not all intended for
combustion. A portion of it only is burnt with the gas, the remainder is heated
by the combustion.
By suitably proportioning the capacities of the air-charging chamber and the
gas pump or gas charge, the temperature of the hot working air is made such as is
desired. If this is made high then the piston which drives the engine furnished
with a shield, but a temperature may be used so moderate that this is not
necessary. And this is convenient if it is desired that the engine should be double-
acting.

page_text: In my first description I shall suppose as being the simplest case, that the gas is
introduced by means of an ordinary pump, injecting it against the pressure within
the chamber where it is burnt. I may observe that in my description I shall
frequently use the term air to signify elastic fluid generally.
For convenience of description I shall suppose the the upper end of the air
charging chamber is the cool end, the lower one the hot end, and I shall
suppose that the working stroke of the piston is upward, its discharge stroke
downward.
I shall take for starting point the time when the pistón is ready to begin its
discharge stroke. At this time the displacer is at the upper or cool end of its
chamber, the space beneath it being full of exhaust air, still retaining considerable
heat.
The piston is at the top of its cylinder, the space beneath it similarly full of
exhaust air.
Communication is open between all the spaces filled with exhaust air.
I may observe that by exhaust air I mean generally air which has discharged its
office of performing work in the cylinder as described. It may in some cases páss
off to perform work elsewhere.
The displacer moves downwards. Above it draws in or is followed by the supply
of atmospheric air; below it expels exhaust through the regenerator and out by
the main eduction valve.
The piston also moves downwards, expelling exhaust in like manner through the
regenerator and main eduction valve. This state of things continues till the
displacer has completed its down stroke, at which time the piston is about midway
in its discharge stroke.
Communication is now closed between the cylinder and the other parts of the
engine. The secondary eduction valve connected directly with the cylinder is
opened.
The displacer now ascends, displacing the atmospheric air above it.
It causes
this to pass through the regenerator into the hot space beneath the displacer.
While this is taking place the gas pump makes its stroke, injecting gas, which
mingles with a portion of the air entering the hot space, as previously described,
is ignited and undergoes combustion, which takes place gradually. This combustion
heats the other portion of the entering air.
While the displacer is making its up stroke, as previously described, the piston
completes its discharge stroke, expelling exhaust through the secondary eduction
valve.
When the strokes above described are completed the space beneath the displacer
is filled with hot air ready for performance of work.
The proper changes of valves having been made communication is now opened
between the cylinder and the other parts of the engine, and the hot air expands in
the cylinder urging the piston which performs its working stroke.
While it is making this stroke the displacer remains at the upper or cool end of
its chamber, stationary or nearly so. The working stroke having been completed
and the proper changes of valves made the point previously taken as starting
point is reached.
In the above described manner of operating the gas pump injects its charge of
gas against the pressure in the displacing chamber, which rises as the displacer
ascends. But as the quantity of gas relatively to the total quantity of working
fluid is small the power needed to work the gas pump is not very considerable.
Instead however of using a gas pump a gas charging chamber and displacer,
with regenerator or passage, may be employed for the purpose of introducing the
gas supply and sending it to mix with the air in the hot space. In this case when
the gas displacer displaces the gas above it, or on its cool side, it sends the gas
through the gas regenerator or passage into the space where combustion is effected,
as previously described, while air or fluid from the hot space beneath the main
displacer enters below the gas displacer or on its hot side..

page_text: Such a second charging chamber instead of taking in gas alone may take in gas
and air mixed in incombustible proportion.
For the mixing of the gas and air for the purpose of combustion any known
suitable form of mixer or burner may be employed in any convenient position
between the regenerator and the hot end of the air charging chamber.
In the method of operating above described the combustion takes place gradually,
but another method may be employed. The gas is introduced into the hot space
only during the first portion of the main displacer's stroke. It is not ignited as it
enters, but it mixes with the air which enters the hot space as it is displaced by
the main displacer, so as to form a combustible mixture beneath the main displacer.
The proper quantity of this having been introduced the stroke of the gas pump or
gas displacer finishes, and about the same time ignition is effected. The main
displacer in the meanwhile is continuing its upward movement, and in doing so it
transfers air from the cool space above it to the hot space below it through the
regenerator, this air taking up the heat which the expansion of the ignited mixture
through the regenerator had previously imparted to it.
The general construction above described remaining the same, one eduction valve
only may be employed, and the exhaust be discharged through this and not through
the regenerator.
In the methods previously described only one regenerator was used to utilise
the heat of the exhaust, and a certain portion of the exhaust was discharged
without passing through the regenerator. But a pair of regenerators may be
employed, and in this case the whole exhaust may be passed through each
regenerator alternately.
Passages are provided governed by valves, so that each regenerator can when
desired be placed either in or out of communication with the air charging chamber,
the cylinder, and the eduction port. During each discharge stroke of the piston the
whole exhaust is sent through one of the regenerators, a portion of it by the
displacer, the remainder by the piston. When the displacer has finished its down
stroke, or that which expels exhaust, communication is cut off between it and the
regenerator, through which it just expelled exhaust, and is opened between it and
the other regenerator. When it ascends it transfers its charge of air to the hot
side through this regenerator, while the piston continues expelling exhaust through
the other regenerator.
During the next discharge stroke the function of the two regenerators is reversed;
each performs the part which the other performed in the preceding stroke. Thus
whenever the displacer transfers its charge from the cold to the hot end of the
vessel, it sends it through that regenerator which in the previous discharge stroke
was heated by passage through it of exhaust.
In the above description I have supposed gas to be the fuel employed, but the
matter employed as fuel may be varied. A liquid whose vapour is inflammable,
such as various hydro-carbons, may be employed to generate inflammable vapour
in any known suitable apparatus at regulated pressure, and a definite quantity of
this vapour may be supplied to the engine and act like gas, as above described;
or a certain portion of the vapour may be admitted by means of a valve allowing
it to flow for a certain time from a vessel at regulated pressure, as may also be done
in the case of gas.
Again liquid such as above mentioned may be injected directly into the hot
chamber so as to be vaporised by the heat within it, and undergo combustion along
with the air.
In such a case the liquid may be injected in numerous small streams, or in such
a manner as to form fine spray, which is dispersed by the air and undergoes
combustion.
When gas is employed as the material for combustion it may be supplied to the
engine in regulated quantity from a reservoir in which it is stored at any pressure
and in any quantity desired. Such a mode of supplying gas to the engine is more
specially applicable for purposes of locomotion.

page_text: Also both the gas and air supplied to the engine may be compressed in vessels
at high pressure, and may work within the engine at high pressure. This method
again is applicable for purposes of locomotion.
Compressed air is now employed in some cases to work locomotive engines.
If the same amount of elastic fluid is compressed as gas and air it would effect
locomotion to much greater distances on account of the generation of heat. The
gas and air issuing from the reservoirs should be delivered to the engine at regulated
pressure, as previously noticed.
When the gas and air thus work at high pressure the elastic fluid which is
discharged from the apparatus above described after performance of work in it
is discharged at high pressure, and is still capable of performing work. For this
purpose it is employed in a second cylinder, or in successive cylinders, as steam is
in a compound steam engine.
In carrying out the operations above described ignition may be effected by
means of any suitable known apparatus. One which may be employed is that
which I described in the Specification of a Patent granted to me on the 19th June
1868, No. 1988, where ignition is effected by the movement of a lamp; but I
improve this form by making the upper part, or the terminal part which enters the
vessel where the mixture is to be ignited, to seat itself as a valve when the lamp is
withdrawn.
The following is another construction which may be employed:-
A flame as of a gas jet or lamp burns within or partially within a passage close
to the igniting port. This passage has two apertures, one for ingress of air, and
the other for egress of the flame or the products of combustion.
Outside the latter
aperture a flame is kept constantly burning. Within the passage is fitted a slide
which, when ignition is about to be effected, is moved by the engine so as to cover
both the apertures. The stem of this slide when it is moved raises in the last part
of its stroke a check valve which covers the igniting port, thus opening the ignition
passage to the chamber containing the inflammable mixture.
In cases where this mixture is at a pressure higher than that of the atmosphere
a small secondary check valve may be fitted on the main check valve. This
secondary valve being first opened by the stem of the slide permits passage of
fluid along a groove or cavity in the stem so as to establish equilibrium in the
ignition passage, immediately after which the larger check valve opens.
After the ignition the slide is retracted, permitting the check valve or valves to
close, and re-opening the apertures of the ignition passage, and the igniting flame
if it should have been extinguished is relighted by the external flame; things are
then ready for repeating the operation.
The movement of the slide may also at its commencement open a valve in the
gas pipe, so as to give a momentary increase to the lighting flame.
The movement of the slide may also change the direction of the igniting jet, so
as to direct it against or towards the igniting port.
In the previous account I described a construction of engine in which the gas
and air were delivered to the engine at high pressure from vessels in which they
were stored. It is evident that the compression of the gas and air might be
effected by means of pumps worked by the engine, the construction of this
remaining in other respects the same.
In the construction of engine which I previously described, in which the gas and
air are burnt gradually, the general construction remaining the same, the regenerator
may be dispensed with, the exhaust passing away directly through the eduction
valve. In such a case one eduction valve suffices.
Fig. 1 is a vertical section of an engine constructed according to my Invention,
and Fig. 2 is a sectional plan of the same. A is the air-charging vessel, the upper
portion of which is kept cool while the lower portion is hot; D is the displacer
furnished with a shield which works in this vessel; R is the regenerator through
which the air flows in passing from one side of D to the other; C is the working

page_text: cylinder fitted with the piston P, which is shewn furnished with a shield; G,
shewn in Fig. 2, is the gas pump; c is a chamber into which this pump delivers
the charge of gas; I is the igniting apparatus; W is a water casing which keeps
cool the upper part of A; s is the supply valve through which the fresh or cool
air is introduced into the cool part of A; u is the valve between A and R; v, the
valve between A and C; e, the eduction valve; o, a pipe through which the
exhaust is discharged; F is a flame burning under A; H is a space heated
by it.
This flame serves to heat the metal of A and C in their lower parts before the
engine begins to work, and also to keep them hot if the engine is worked with
frequent intermissions.
In cases where the engine is worked continuously for long periods it is not
necessary to maintain this flame.
The gas delivered into c by the gas pump G issues from c in numerous jets
through the apertures i, i, and also through the tube t; the mouth of this tube
opens near the valve of the igniting apparatus, which governs communication
between it and the interior of the vessels; this is done in order to ensure the
existence, of inflammable mixture close to that valve.
The course of operations takes place as follows:-
:-
For starting point I shall take the time when P has just completed its working
stroke, and is at the top of its cylinder ready to commence its down or discharge
stroke.
D is also at the top of A. The spaces below D and P and the spaces in R and
the adjoining passages are filled with exhaust air, that is, air which has finished
its performance of work on P by expansion.
The valves and e are open, u is shut, D descends. Above it draws in or is
followed by air entering through the supply valve 8, which is either a suction valve,
as shewn in the Drawing, or may be opened by the engine. Below, D expels
exhaust through v into C and out by the eduction valve e.
Meanwhile the piston of the pump G is moving upwards in its cylinder taking
in the supply of gas..
While D is performing its downstroke, as above described, P is performing the
first half or portion of its downstroke. Below, it expels exhaust through e, while
above, it is followed by atmospheric air.
When the pistons of A and G have completed their strokes and taken in their
respective charges of air and gas their supply valves are closed, and the valve
between A and C is also closed; u the valve between A and R is opened.
D now ascends, displacing the air above it and causing it to pass through R into
the lower part of A. below D. At some time while this is taking place the piston
of G delivers its charge of gas into c, and this issuing from the apertures in c mixes
with air flowing from R into A is ignited by the igniting apparatus I and burnt.
The heat of the combustion raises the pressure of the air or elastic fluid in A and R
and the spaces connected with them.
The delivery of gas from the gas pump might go on during the whole of D's
up-stroke, but I consider it best to operate as follows:-In the first part of D's
up-stroke it sends air through the regenerator and passages, clearing out products
of combustion from the lower part of the air, vessel. The gas pump then injects
the gas and the combustion takes place. Sometime before D completes its up-
stroke the supply of gas is stopped and the combustion ceases, and D during the
remainder of its up-stroke sends air through the regenerator and passages.
When the strokes above described have been completed D is at the top of its
cylinder, and the space beneath it in A, and the spaces in R, and the adjoining
passages are full of air whose pressure has been raised by the heat of the com-
bustion; P is at the bottom of its cylinder ready to commence its up or working
stroke.
e is now closed and v is opened. High pressure air passes from A and R into C

page_text: below P, and expanding in C urges P upwards, causing it to perform its working
stroke.
Meanwhile D remains at the top of A, stationary or nearly so.
The piston of the gas pump might also remain stationary, but it may be
moving, taking in its supply.
P having completed its up-stroke u is closed and e is opened, and the point
previously taken as starting point is reached.
In the above account I have supposed the gas entering A to be burnt gradually
as it enters, but the mode of operating may be varied as follows:-
While D moves through a portion of its up-stroke, G delivers the whole of its
charge of gas into A, this mixing with the air below D so as to form a combustible
mixture. The mixture so formed is then ignited, and the expanding products of
combustion rush through R into the space in A above D, compressing the air
therein. As D continues to ascend it drives the air above it through R into the
space beneath it, and this air in passing through R takes up the heat previously
imparted to R by the passage through it of the expanding products of combustion.
Also in entering A it takes up heat from the metal heated by the combustion of
the inflammable mixture.
When D reaches the top of A, the space below it and the space in R and the
adjoining passages are filled with high pressure air at the temperature desired,
ready for performance of work.
In the construction above described the whole exhaust is discharged through
the eduction valve e, and the heat of the exhaust is not utilised. But this heat
may be utilised by being imparted to a regulator, which heats the air previous to
combustion.
When it is desired to utilise in this way the heat of the exhaust, one con-
struction is as follows:-
A second eduction valve is provided in communication with the regenerator,
as shewn in Fig. 1, by the dotted lines at e¹. While the displacer is expelling
exhaust, e is shut and e¹ open, and both D and P expel exhaust from their
respective vessels through e¹. When D has completed its downstroke or stroke
which expels exhaust, e¹ is shut and e is opened, and during the remainder of its
stroke P expels exhaust through e.
Another construction for effecting the mixture of the gas and air is shewn in
the part transverse section Fig. 3. The gas delivered by the gas pump G passes
into the tube u¹. This tube is pierced with an aperture or apertures opening
into the passage by which the air from the regenerator flows to the air charging
vessel. One such aperture is shewn in the Figure at x. The stream of gas draws
in air through x, as in a Bunsen, burner, and thus a mixed, stream of gas and air
is created in u¹, which passes into A at y and there meets the other air coming
from the regenerator, and entering A through the apertures i, i, and mixing with
this air undergoes combustion.
The form of the passage u¹ and of the orifices may be a good deal varied.
Also forms of passage for effecting the mixture of the gas and air like those which
I have described in previous Specifications might be employed.
For moving the displacer direct pressure or force may be brought to bear upon
it so as to lessen the work thrown on the cam or other mechanism connecting the
displacer with the engine. This may be done in the ways which I have explained
in the Specification, No. 5270, above referred to.
Instead of taking in gas and air at or near the atmospheric pressure, the engine
may take them in at high pressure. It may take them in from reservoirs in which
they are stored at high pressure, or it. may take them in from pumps worked by
the engine.
In such a case one mode of working is to allow the entering high pressure air to
act on D so as to drive the engine. But the connection between D and the engine
may be of such a nature that this is not desirable. In such a case the following.
plan may be adopted. .
·

page_text: The exhaust discharged from e passes off at a high pressure, though lower than
that which has been used in the cylinder C, and the exhaust thus discharged is
utilized by performing work in another cylinder, just as steam is used in a
compound engine.
In this case the pressure urging -D when it takes in its supply can be made such
as desired.
The shield attached to the piston P may be dispensed with and the engine
may be made double acting by duplication of the necessary parts.
The constructions above described are applicable when inflammable vapour is
used as the fuel in the engine instead of gas. The vapour may be generated
in a boiler and supplied to the engine at pressure regulated by a regulator or
governor.
Also inflammable liquid such as petroleum or hydro-carbons may be supplied as
fuel. This may be injected so as to be mixed with the air in the form of fine
spray, which may be done by any known method, and the mixture may be burnt
as previously described in the case of gas.
An apparatus for effecting ignition is shewn to an enlarged scale at Figs. 4 and 5 ;
Fig. 4 being an external elevation, and Fig. 5 being a longitudinal section.
Here C is a small cylinder in which a plunger S is caused to reciprocate by a
lever R worked by the engine. The upper part of the plunger S seats as a valve V
on an aperture to the chamber H which contains the inflammable mixture that is
to be ignited. Through the plunger there is a passage F, which when the valve V
is seated faces apertures o', 02, through the side of the cylinder C. Within the
passage F there is a flame fed by gas, or oil, or any suitable material, supplied by a
flexible pipe e to the nozzle p. A check valve i allows passage of the gas or liquid
from p to F, but prevents flow in the reverse direction.
fis an external flame kept burning in front of the opening o². When the passage
through o¹ and o² is vertical, as shewn, or a little inclined, the combustible material
rising through o² is ignited by the flame f. If this passage is placed horizontally,
or nearly so, a draught may be created through it by means of a chimney or of
bellows, w is a water casing to keep the parts about V cool. x is a groove cut in
the side of the plunger S to allow passage for a small quantity of air.
The action of the apparatus is as follows:-When the valve V is seated the flame
in F is ignited and turns, as shewn in Fig. 5. When it is desired to prepare for
ignition the plunger S is moved forwards or towards H, closing the openings o'
and o² and shortly afterwards bringing the groove x into communication with H,
so that air or elastic fluid can pass from H into F, raising the pressure in F and
establishing equilibrium of pressure in F and H.
This rise of pressure in F closes the check valve i. As the motion of S proceeds
the flame in F enter the chamber H and ignites the inflammable mixture therein.
The plunger S being then retracted the parts are brought back to the original
position shewn, the supply of gas or liquid to F is reopened, and the flame in F if
it had been extinguished is re-lighted by the outer flame f.
displacer D; Fig. 7 shews the cam G¹
the cam I¹ for working the igniting
working the valve u; Fig. 10 shews
shews the cam e' for working the
Fig. 6 shews the cam D¹ for working the
for working the gas pump G; Fig. 8 shews
apparatus I; Fig. 9 shews the cam u² for
the cam v for working the valve v; Fig. 11
valve e.
Having thus described the nature of my Invention and in what manner the
same is to be performed, I claim,----
First. The construction of a caloric engine in which air passed in successive
charges from the cold end to the hot end of a vessel by means of a displacer or
piston, is heated in its course by combustion of inflammable gas vapour or liquid
mixed with it, and the air having its pressure thereby raised is afterwards admitted
into a cylinder to perform work on its piston, substantially as herein described
with reference to the accompanying Drawings.
1

page_text: Second. The construction of igniting apparatus, substantially as herein described
with reference to Figs. 4 and 5 of the accompanying Drawings.
In witness whereof, I, the said Matthew Piers Watt Boulton, have hereunto
set my hand and seal, this Fifteenth day of September, in the year of our
Lord One thousand eight hundred and eighty one.
PAREMAK
M. F. W. DOULTON. (L.S.)