Year: 1899

page_text: I, EDUARD HÖFLINGER, of Gundenhof, Gleichenberg, in the Empire of Austria,
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention relates to explosion engines and is illustrated in the accompany-
ing drawing of which
Figure 1 is a section of a portion of an combustion gas-engine with my improve-
ments applied thereto.
Figure 2 is a similar section of a modified form of the engine.
Figure 3 is a modified form of the gas and air compression chamber in which
a single plunger or piston is used.
Figure 4 is a further modified form of the said compression chamber.
Figures 5 to 8 show diagrams theoretically worked out in connection with the
invention and
Figure 9 is a theoretical diagram of Diesel's known gas-engine.
The said invention consists in compressing atmospheric air to varying degrees
according to the variations in the load on the engine and in this manner producing
variation in the explosive mixture with exhaust and fresh gases which is each
time consumed during a non variable outward stroke of the piston see lines 2, 3 5,
6 8, 9 in the diagrams shown in Figures 5 and 7, or the outward stroke of the
piston may be made to vary and to increase in length in proportion as the com-
pression of the air is reduced, thus obtaining with reduced compression a slower
combustion to such an extent that the combustion curves 2, 3 5, 6 8, 9 Figures G
and 8, cut the adiabatic line 3, 4 of the full load diagram.
The variable compression of the atmospheric air may be effected.
(a). By causing the air to be compressed in a cylinder through the intervention
of the engine shaft always to the same degree and then bringing this compression
to the desired degree by partial combustion of the explosive mixture of fresh and
exhaust gases with the air.
(b). By causing the engine piston to compress the air to various degrees by
varying the capacity of the usual clearance or compressing space.
(c). By causing the engine piston to compress the air to various degrees by vary-
ing the time of closure of the suction valve without altering the compression
space.
air
In the said drawing a indicates the working cylinder. the engine piston, c the
compressor, d the plunger of the air compressor arranged at 180° in advance of
the engine piston minus the non varying length of the clearance c. f is the com-
pression chamber for the air, g is the compression chamber for the exhaust gases, the
chambers f and g communicating with each other through the valve h and through
the needle valve i which lafter acts as return valve, the chamber f also com-
municating with the cylinder a through the valve & which opens towards f and g.
is an air vessel communicating with the compressor e through a valve m and
with the chamber f through a valve n.
o and are two plungers connected together by a lever or the like in such a

page_text: manner that a pressure exerted in the chamber is communicated to the
chamber f, q is a suction valve, and r is an exhaust valve.
The engine constructed according to Figure 1, operates as follows:
Supposing the piston d of the air compressor c in the position shown has com-
pressed the air to atm. and the air vessel 7 to contain compressed air of a. atm.
further the engine piston b to have completed its expansion stroke and to be at
the point of starting the exhaust, and the chamber to contain
under
sure from the previous expansion, stroke while at the same time the plungers o
and p are supposed to be under brake power thus preventing the gases in the
chamber from expanding.
9
gases
pres-
During exhaust by the piston b the valve closes; from the air space / air
at atms. pressure flows into f through the valve n, the compression plunger d
arrives at the end of its stroke, forces the air compressed to atm. into the
chamber and starts its suction stroke. At this moment the combustible is intro-
duced into the chamber and vaporized without mixing air therewith.
0
The above mentioned brake power on the plungers and is then withdrawn.
By now opening the valve and moving the piston o in the direction of the
arrow the air flows from f into g and is therein consumed burning with an
inverted flame providing the mixture of combustible and exhaust gases has the
required ignition temperature and that the inflow is not effected with too much
pressure.
This combustion raises the pressure in 9 which pressure is communicated
through the lever to the plunger and so effects a further compression of the
air in f.
The combustion is continued until the air in f as well as the mixture of the
combustible and exhaust gases in attain the density required for the momentary
load on the engine whereupon the valve is then closed.
The aforementioned operations must be effected as has been stated during the
exhaust stroke of the piston b.
Directly the piston 6 starts on the outstroke the valves k and h are opened and
the plunger o moved in the direction of the arrows. This causes the mixture of
combustion material and exhaust gases from the previous stroke together with
the last exhaust gases to be forced into f. This operation must be carried out
quickly so as to compensate the reduced pressure owing to the outstroke of the
piston by the expansion from the combustion; and as the plunger o does not fully
move against the bottom of the chamber g it will be obvious that a small portion
of the combustion material and gas mixture remains therein. In order to cause
this portion to be equally consumed it is necessary to move the plunger o in the
direction of the arrow into its primitive position it occupied before the intro-
duction of the combustion material Figure 1. In consequence of this movement
a portion of the mixture of air and exhaust gases returns into g and effects the
combustion of the remaining portion therein.
By now closing the valve h and at the same time putting the brake power upon
the plunger o at the exact moment when the exhaust gases in g have acquired the
pressure and temperature proper for the next evaporating and combustion process
thus preventing their further expansion, obviously the work of ultimately com-
pressing them will be saved. Because if this exhaust gases in g are allowed to
participate in the full expansion they require re-compressing after the expansion.
The two plungers o and p Figures 1 and 2 may if desired be arranged as shown
in Figure 4 or they may be replaced by a single plunger Figure 3.
Of course in this case the chambers ƒ and g together with the valves h, i kand
evlinder a must be arranged in accordance with the modification as shown at
Figure 3 or as Figure 4.
If then the isothermal combustion for each load on the engine be kept up equally
long a diagram as shown in Figure 5 is obtained.
When however, as previously mentioned for light load the combustion is kept
on for a longer time the diagram Figure 6 is obtained. Where the load on the

page_text: engine is so light that not enough combustion material is required to bring the
isothermal combustion from 8 to 9, Figures 5, 6, 7, 8, the adiabatic line will be
found to commence earlier as is the case with steam engines, see line v v¹.
The operation so carried out in the engine indicated in Figure 2 differs from
the one previously described only in that the variation in the compression of the
air is effected through the action of the engine piston b, thus enabling the air
compressor c and the valves k and n to be omitted. The cylinder a and chamber f
are in communication and the lever arrangement forming the connection between
the plungers o and p is fitted with a removable coupling.
The working of the engine is as follows:
The plunger o, is, as in the previous case, under brake power and in g are
contained, as before the exhaust gases to which the combustion material is
introduced.
The piston works on the 4 cycle principle. Supposing the piston b in its
position Figure draws in air and is on the point of starting compression, it
becomes then necessary to move the plunger p in the direction either of the arrow s
or arrow t sooner and in accordance with the required compression. After adjust-
ing the plunger to its correct position the coupling of the lever arrangement
is tightened up but without as yet taking off the brake power from the plunger o.
Thereupon the piston 6 starts the compression and the moment the air pressure
in f exceeds the pressure of the gases in g, air passes from f through the valve i
into
and effects the combustion in the latter and raises the pressure in g.
But
as acts also as a return valve and notwithstanding the continuation of air
compression by the piston 6 no air can flow into g until the compression in f
is again in excess thereof. At the moment of the piston b arriving at its
inner dead centre and starts the expansion stroke combustion takes place
through the opening of the valve and movement of the plunger o in the direction
of the arrows together with the operation described with reference to Figure. 1.
Thus the variations in the air compression are effected from the motor shaft and
the variations in the compression of the combustible are effected through partial
combustion.
The diagrams relating to this mode of operating are shown in Figures 7 and 8;
the time of combustion (outstroke of piston) being constant in Figure 7 but
variable in Figure 8.
If as stated at c in the preamble the volume of air is varied instead of the com-
pression space the description with regard to Figure 2 applies with the only
difference that the removable coupling between the plungers o and P becomes
unnecessary and that the suction valve requires to be so regulated as to close
sooner or later according to the variation in the volume of air required. In this
case he ever the engine piston causes a vacuum with a slight load. But this loss
in useful work is compensated for at the next compression stroke by the air
pressure from without upon the piston b.
This method has the great advantage that when less combustible is burned in
the machine and consequently less air is consumed there will be no useless com-
pressing and heating of air
1.
The diagrams are similar to Figures 7 and 8 and the pressure lines 1, 5 1, 8
although rising to the same level as those in Figures 7 and 8 they become corre-
spondingly shorter through the point 7 falling further inward as indicated by the
arrow Z Figure 8.
1
.
A clear understanding of the difference existing between the method according
to this invention and that of Diesel's gas-engine on account of the difference in
the relative conditions of pressures in the cylinders, can be obtained by a comparison
of the diagrams Figures 5 to 9.
Figures 5 and 6 enable the proportions in the relative pressures, to be ascer-
tained with reference to the method carried out in Figure 1, and Figures 7 and 8
similarly show the same with reference to the method carried out in Figure 2.

page_text: In regard to the diagrams 7 and 8 as compared with diagram 9 it should be
noted, that according to both methods pure atmospheric air is compressed through
the action of the fly wheel; but Diesel compresses always to the same degree for
light and for full load, while according to my method the compression is regulated
to suit the prevailing load.
Diesel and the present invention (referring to the method carried out in Figure 2)
ought with full load and same size engines to compress to the same degree and
to obtain the same diagram.
This however is not the case.
As may be gathered from the foregoing description to burn in 9, during the air
compression stroke and with the object of compressing the combustion material,
a portion of this latter together with a portion of the atmospheric air which is
being compressed. Thus at the time of starting the real combustion in other
words the working stroke I have already consumed a portion of the combustion
material and in the present case therefore, unlike Diesel's patent, it is not required
to burn the entire charge and consequently do not require air compressed to the
same high degree.
My diagram for full load must therefore be lower than that of Diesel's engine.
The disadvantage as shown in the diagrams which exists in appearance only with
regard to Figure 2 as compared with Diesel's engine is compensated for by having
to deduct from the Diesel diagram the work absorbed by the compressing pump
for the combustion material, which of course is not the case with regard to my
diagram inasmuch as the compression of the combustion material in my case is
effected by the direct combustion thereof. Therefore it will be clear that my
diagram for the arrangement indicated in Figure 2, even with full load, must be
lower to an extent equal the work performed by the injection pump.
Dated this 12th day of June 1899
I, EDUARD HÖFLINGER, of Gundenhof, Gleichenberg, in the Empire of Austria,
Engineer, 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:-
This invention relates to internal combustion engines and is illustrated in the
accompanying drawings, in which:-
Figure 1 is a section of a portion of a combustion gas-engine with my improve-
ments applied thereto.

page_text: Figure 2 is a similar section of a modified form of the engine.
Figure 3 illustrates a modified form of the gas and air compression chambers in
which a single plunger or piston is used.
Figure 4 illustrates a further modified form of the said compression chambers.
Figures 5 to 8 show indicator diagrams theoretically worked out in connection
with the invention, and,
Figure 9 is a theoretical diagram such as obtained from Diesel's known gas-
engine.
The said invention consists in compressing atmospheric air to varying degrees
according to the variations in the momentary load on the engine, and thus varying
the explosive mixture of air and exhaust and fresh gases, such mixture being
consumed during a non variable stroke of the piston, see lines 2-3, 5-6, 8—9
in the diagrams shown in Figures 5 and 7, or the period of combustion may be
made to vary and to increase in length in proportion as the compression of the air
is reduced, thus obtaining with reduced compression a slower combustion to such
an extent that the combustion curves 2-3, 5--6, 8-9, Figures 6 and 8, cut the
adiabatic line 3-4 of the full load diagram.
The variable compression of the atmospheric air may be effected.
(a). By causing the air to be first mechanically compressed in a cylinder by
suitable means in connection with the engine shaft, to a uniform degree, and then
further compressing the same to the required degree by partial combustion of an
explosive mixture of fresh and exhaust gases with this partially compressed air.
(6). By causing the engine piston to compress the air to various degrees by vary-
ing the capacity of the usual clearance or compression space.
(c). By causing the engine piston to compress the air to various degrees by
varying the time of closure of the suction valve without altering the compression
space.
In the said drawing a indicates the working cylinder, 6 the engine piston,
the air compressor, the plunger of the air compressor.
The main crank of the engine, which is driven by the piston b is arranged in
advance of the crank which drives the piston d of the air compressor, by an angle
of 1800 plus the angle through which the cranks would have to rotate in order to
move the piston d through the space c. Thus when the piston is in the position
shown in Figure 1 the main crank of the engine is at its bottom dead centre and
the piston is at the extreme limit of its forward stroke, but the crank which
drives the piston d has not yet arrived at its upper dead centre, and only does so
after the piston 6 has commenced its exhaust or backward stroke.
f is the compression chamber for the air, g is the compression chamber for the
exhaust gases, the chambers f and 9 communicating with each other through the
valve h and through the needle valve i which latter acts as a non-return valve for
gases passing into the chamber g through said valve the chamber f also com-
municates with the cylinder a through the valve which opens towards f and g.
1 is an air vessel communicating with the compressor e through a valve m and
with the chamber f through a valve n.
o and are two plungers connected together by a lever or the like in any
suitable manner such that a pressure exerted in the chamber g is communicated
to the chamber f, 9 is a suction valve, and r is an exhaust valve.
0
The manner of operating the pistons and p is as follows. The piston o owing
to the nature of its connection with the piston 2, always moves in the opposite
direction to this latter, that is to say, if the piston o moves in the direction of
the arrow t then the piston p necessarily moves in the direction of the arrow s.
It is therefore only necessary to provide means for directly operating one of said
pistons. The stroke of said pistons however is required to be variable according
to the load on the engine. In Figure 1 of the accompanying drawing
illustrated a suitable means for operating said pistons o and P which means con-
sists of the cam u suitably supported and rotated by means of any appropriate
have

page_text: gearing not shown in the drawings from the main shaft of the engine. Assuming
the engine to be fully loaded, then the cam is in the longitudinal position shown
in Figure 1.
(
Now assuming that the cam is being driven round in the direction of the
arrow, and that the roller of the cam truck is at the point 2 of the cam surface;
it is clear that said roller will pass over the concentric portion 2-5 and that
during this time the plunger will be unable to move outwards in the direction
of the arrow t, and will thus be held stationary. The spring S presses the cam
truck against the cam and opposes motion of the plunger in the direction of the
arrows as will be readily understood. When the point 5 of the cam u comes
under the cam truck, the latter will move over the portion 5-4 and in the direction
of the arrow under the influence of the spring S, thereby causing the plunger o
to move in the direction of said arrow and the plunger p to move in the direction
of the arrow s. By this action air is forced through the valve i. The valve i is
normally kept against its seat by a cylindric spiral spring shown in Figure 1 as
encircling the spindle of said valve and abutting at one end against a suitable
head thereon and at the other end against the fixed casing of the air vessel . The
valve thus permits gases to pass from the chamber f into the chamber provided
that the gases in f are at a suitable pressure, but does not permit any flow of gases
from the chamber g into the chamber f. The cam truck then runs over the con-
centric portion 43 of the cam u during which time the plungers and p are of
course held stationary. When the cam truck arrives at the point 3 the plunger o
is moved inwards in the direction of the arrows thereby forcing the gases contained
in the chamber g into the chamber f through the valve h which is at this moment
held open for that purpose by appropriate cam mechanism. If the load. on the
engine is reduced then the stroke of the pistons and will require to be reduced
so as to reduce the quantity of combustible introduced into g. To enable this to
be effected I arrange the cam so that it can slide longitudinally along its shaft,
and I form the surface 4-3 of said cam tapering from the bottom towards the
top as illustrated in Figure 1. Now if the cam be moved upwards from the
position in which it is shown in Figure 1 so that the truck moves over the
portions 5-4, 4-3, 3-2, then the pistons o and will not move through a
distance corresponding to the portion 3-2 of the cam as before, but only through
a distance corresponding to the much shorter portion 3-2 of the cam. By this
means the combustion in ƒ and g is considerably reduced. I have not shown on
the drawing any means for sliding the cam u longitudinally along its shaft, to
which it is of course connected by means of a sliding feather so as to be rotated
with said shaft; as I may employ any suitable automatic means to effect such
sliding action, for instance I may connect the cam to the sleeve of an ordinary
steam engine governor driven by and governing the engine, the connection being
such that when the sleeve of the governor rises, consequent upon a diminution
in the load on the engine, then said cam is also raised or lifted directly or through
appropriate connections by said governor sleeve; thereby as above explained,
reducing the length of stroke of the pistons o and p and also the amount of com-
bustion occurring in the chambers fand g, as required. It will be obvious that
between the extreme longitudinal positions which the cam may assume, there
is a range of positions, each corresponding to a different length of stroke for the
pistons o and and therefore corresponding to the load momentarily on the engine
as above explained, the said cam being shifted by means of the governor or
other device above referred to into the exact longitudinal position corresponding
to the requirements regulated by the momentary load on the engine. While the
cam truck
travelling over the concentric portion 5-2 of the cam u, the piston
or plunger o remain at the extreme inward point of its stroke and the piston f
remains at the extreme outward point of its stroke. It will readily be understood
that the charge of combustible is varied automatically by means of the cam u and
and its connected parts, since by varying the stroke of the plunger o the capacity

page_text: of the chamberg is correspondingly varied and therefore also the quantity of
combustible admitted thereto is likewise-varied to suit the requirements regulated
by the momentary load on the engine.
With the arrangement illustrated in Figure 1 it is not necessary to adjust the
plungers and before starting the engine, as the quantity of combustible
admitted will obviously be regulated automatically by the cam ut.
It should be noticed that the valves h, k and are opened and closed in the
sequence and for the periods that are herein pointed out, and which are necessary
to the operation of the motor. The motion of said valves is preferably controlled
in one direction by suitable spiral springs encircling their spindles and arranged
to keep said valves against their respective seats, and are lifted off their seats by
cam mechanism or any other appropriate gearing at the times desired. Such cam
mechanism would be driven positively from the main shaft of the engine and would
therefore work the said valves in proper and regular sequence with regard to the
motion of the plungers and p, engine piston, and air compressor piston d. As
the construction of suitable cam mechanism will easily be understood I have not
illustrated any special form thereof in the drawing. The combustible employed
may be any suitable hydrocarbon such as petroleum vapour and may be introduced
into the chamber g through a valve (not shown on the drawings) from a pump or
a spraying device operated from the main shaft of the engine. Such apparatus
however forms no part of my invention and I have not therefore illustrated them
in the drawings; they are morcover well known, and their application to the
engine herein described will be readily understood. The gearing for introducing
the combustible into the chamber g must be arranged however so as to effect such
introduction at the moment when the plunger d of the air compressor c is just
commencing its suction stroke and the piston 6 has already commenced its exhaust
stroke, and the cam truck in the arrangement illustrated in Figure 1 has just
arrived at the point 5 of the cam and is commencing to move in the direction
of the arrow t.
The engine constructed according to Figure 1 operates as follows:
Supposing the piston d of the air compressor c in the position shown has com-
pressed the air to a pressure of atmospheres, and the vessel 7 therefore to contain
compressed air of atmospheres; further the engine piston b to have completed
its expansion or explosion stroke, and to be at the point of starting the exhaust
stroke, and the chamber g to contain gases under pressure from the previous
expansion stroke, while at the same time the plungers o and p are supposed to be
at the point 2 and to be just about to commence moving over the concentric
portion 2-5 of the cam thereby preventing as stated above the gases in the
chamber from expanding. This positive temporary fixing or holding in one
position of the plungers o and p is hereinafter referred to as the application of
brake power to said plungers.
During the exhaust stroke of the piston the plungers o and p are at first held
against motion by their cam truck being on the portion 2-5 of the cam u; the
valve k is closed and the valve is opened, by suitable cam mechanism not shown
on the drawing but whose construction will be obvious, air from the air space /,
at atmospheres pressure flows or escapes into f through the valve n, the com-
pression plunger d then arrives at the end of its stroke, forcing the air compressed
tor atm. from the space e into the chamber 1, and afterwards starts its suction
stroke. At this moment the combustible is introduced into the chamber g and
vaporized without mixing air therewith. If with the combustible air was also
simultaneously introduced into the chamber g, combustion would take place therein
immediately the supply began and the further introduction of the combustible
would therefore be rendered difficult. I obviate this drawback however by intro-
ducing the air required for combustion into the chamber g after the introduction
therein of the combustible, by the means hereinafter described. At this moment
the cam truck reaches the point 5 of the cam, and the piston o commences to
move in the direction of the arrow t under the influence of the spring S. By the

page_text: opening of the valve i as hereinbefore explained and the actuation of the piston o
in the direction of said arrow t air flows or is driven by the plunger which is
of course displaced in the direction of the arrow s, from the chamber f into the
chamberg and the combustible is then consumed in the latter, providing that
the mixture has the proper ignition temperature, and that the inflow is not affected
with too much pressure.
The valve remains open during this time, but acts with regard to the cylinder
or chamber as a non-return valve, preventing the return of the gases which leave
said cylinder through said valve. Now the further the piston o moves outwards
in the direction of the arrow t, the further will the piston p move inwards in the
direction of the arrow s. The explosion of the gases in the chamber g has the
effect of further compressing the air in f and of causing a small portion thereof
to be forced through said valve i into the chamber 9, where it is burned or
ignited, thereby effecting an increase in the pressure of the gas contained in the
chambers or cylinders f and g. In order to prevent the gaseous mixture return-
ing under the increased pressure into the chamber f, the valve i is as mentioned
above formed as a non-return valve with respect to the chamber f.
The combustion is continued until the air in f as well as the mixture of the
combustible and exhaust gases in g attain the density required for the momentary
load on the engine whereupon the valve i is then closed by its spring, and the
cam-truck of the plungers o and runs over the concentric portion 4-3 of the
cam 1.
The aforementioned operations must be effected as has been stated during the
exhaust stroke of the piston b.
Directly the piston b starts on the outstroke, the valves and are opened by
their cam mechanism referred to above; and the plunger o is moved in the direc-
tion of the arrow s, by the cam truck passing over the portion 3-2 of the cam u.
This causes the mixture of combustion material and exhaust gases from the
previous stroke to be forced from g into f through the valve h. This operation
must be carried out quickly and the cam portion 3-2 shaped accordingly, so as
to compensate for the reduced pressure due to the outstroke of the piston which
results from the expansion of the combustible, and as the plunger o does not fully
move against the bottom of the chamber g it will be obvious that a small portion
of the combustible material and gas mixture remains therein. If it is desired to
cause this portion to be also consumed it will be necessary to move the plunger o
in the direction of the arrow t into the position it occupied before the introduction
of the combustion material. To effect such movement of the plunger o I may
obviously adopt a suitable form for the cam by forming a recessed portion in
the periphery thereof at about the point 2. In consequence of this movement of
the plunger o a portion of the mixture of air and exhaust gases returns into g and
effects the combustion of the remaining portion therein.
The valve his now closed by the aforementioned cam mechanism, and at the
same time the cam truck of the plungers o and p commences to move over the
concentric portion 2-5 of the cam u, thereby preventing the further expansion
of the gases in g, at the exact moment when said gases have acquired the pressure
and temperature required for the next evaporating and combustion process. The
work of ultimately compressing the gases will obviously be saved, because if these
exhaust gases in g were allowed to participate in the full expansion they, would
require to be again compressed after the expansion.
The two plungers o and p Figures 1 and 2 may if desired be arranged as shown
in Figure 4 or they may be replaced by a single plunger ul Figure 3.
Of course in this case the chambers f and g together with the valves h, i and k,
and cylinder a must be arranged in accordance with the modifications as shown at
Figure 3 or as Figure 4.
If then the isothermal combustion for each load on the engine be kept up
equally long a diagram as shown in Figure 5 is obtained.
When however, as previously mentioned, for light load the combustion is kept

page_text: on for a longer time the diagram shown in Figure 6 is obtained. Where the load
on the engine is so light that not enough combustion material is required to bring
the isothermal combustion from 8 to 9, Figures 5, 6, 7, 8, the adiabatic line will
be found to commence earlier as is the case with steam engines, see lines v v¹.
The operation so carried out in the engine indicated in Figure 2 differs from
the one previously described, only in that the variation in the compression of the
air is effected through the action of the engine piston b, thus enabling the air
compressor d and the valves k and n to be omitted. The cylinder a and chamber f
are in free communication with each other, and the lever arrangement forming
the connection between the plungers o and p is fitted with a suitable coupling
device enabling the plunger p to be moved and adjusted independently of the
plunger o. Such coupling device may for example comprise a removable pin
passing through one end of the lever connecting the rods of the plungers o and p
and adapted to be also passed through suitable apertures either in the rod of the
plunger o or in the rod of the plunger p according to the end of the lever con-
necting the said rods at which the pin is located. Thus by removing the pin, the
plunger p may be adjusted independently of the plunger and by then replacing
the pin in the end of the connecting lever and the corresponding aperture in the
plunger rod, the plunger p may be adjusted as desired.
The plunger o, is, as in the previous case, under brake power, although the
arrangement is not shown in Figure 2 as it would be identical with that shown
in Figure 1. In g are contained, as before, the exhaust gases to which the com-
bustion material is introduced.
The piston b works on the four-stroke cycle principle. Supposing the piston b
to have completed its suction stroke as shewn in Figure 2 and to be on the point
of starting its compression stroke, it is necessary to now adjust the plunger p in
the direction either of the arrows or arrow t according to the degree of compression
required. After adjusting the plunger p to its correct position, the aforementioned
coupling device of the connecting lever is locked or put into action, thereby posi-
tively connecting the plungers o and p, but without as yet taking off the brake
power from the plunger o. Thereupon the piston b starts the compression, and
the moment the air pressure in f exceeds the pressures of the gases in air passes
from through the valve i into g, and effects the combustion in the latter and
raises the pressure in g. At the moment of the piston b arriving at its inner
dead centre, and starting the expansion stroke, combustion takes place through
the opening of the valve h and movement of the plunger o in the direction of the
arrows together with the operation described with reference to Figure 1.
Thus the variations in the air compression are effected through partial com-
bustion.
The diagrams relating to this mode of operating are shown in Figures 7 and 8;
the period of combustion (outstroke of piston) being constant in Figure 7 but
variable in Figure 8.
If, as stated at c in the preamble, the volume of air is varied instead of the
compression space, the description with regard to Figure 2 applies with the only
difference that the adjustable coupling device between the plungers
o and p
becomes unnecessary, it only being necessary for said plungers to be connected
as illustrated, and that the suction valve q requires to be so regulated as to close
sooner or later according to the vibration in the volume of air required. It will
be obvious that suitable cam mechanism may be easily arranged to effect this
closure of the suction valve in the manner desired. In this case however the
engine piston causes a vacuum with a slight load. But this load is compensated
for in useful work at the next compression stroke by the air pressure from without
acting upon the piston b.
This method has the great advantage that when less combustible is burned in
the engine, and consequently less air is consumed there will be no useless com-
pressing and heating of air.

page_text: The diagrams are similar to Figures 7 and 8, and the pressure lines 1—5, 1—8,
although rising to the same level as those in Figures 7 and 8, become correspond-
ingly shorter as the point 1 falls further in the direction indicated by the arrow z¹,
Figure 8.
Å clear understanding of the difference existing between the method according
to this invention and that of Diesel's gas-engine on account of the difference in
the relative conditions of pressures in the cylinders, can be obtained by a com-
parison of the diagrams given in Figures 5 to 9 inclusive.
Figures 5 and 6 enable the proportions in the relative pressures to be ascertained
with reference to the method carried out in Figure 1, and Figures 7 and 8
similarly show the same with reference to the method carried out in Figure 2.
In rigures 7, 8 and 9 the curves shown are as follows, viz. :-
1-2, 2-3, and 3-4, show the full load.
1-5, 5-6, and 6-7, show mean load.
1-8, 8-9, and 9-0 show light load.
In Figures 5 and 6 the curves
I-I, 1-2, 2-3, and 3-4 show the full load.
1-I, I-5, 5-6 and 6-7 show mean load.
1-I, I-8, 8-9 and 9-0 show light load.
The difference of diagrams 5 and 6 compared with diagram 9 is easily understood.
In regard to the diagrams 7 and 8 as compared with diagram 9 it should be
noted that according to both methods pure atmospheric air is compressed through
the action of the fly wheel; but Diesel compresses always to the same degree for
light and for full load while according to my method the compression is regulated
to suit the momentary prevailing load.
As will be seen from Figures 5 and 7 the position of the points 0, 7, and 4,
corresponding to the intensity of the final pressure, also varies with the load. If
it is desired to keep the final pressure uniform for all loads, then the combustion
lines 5-6, 8-9, must be continued until they cut the adiabatic line 3-4 of the
full load diagram (points 6 and 9, Figures 6 and 8). This is effected by making
the portion 3-2 of the cam longer, whereby the plunger o will be moved more
slowly in the direction of the arrow s, and consequently the mixture of com-
bustion material and exhaust gases from the previous stroke will be forced more
slowly from g into f and the resulting combustion will be of longer duration but
will be less active and take place at a lower pressure.
The quantity of combustible introduced into the chamber is varied according
to the load on the engine in the manner herein before described. It will be
apparent from the diagrams shown in Figures 5 and 7 that the period of com-
bustion always remains the same, as the lines 2-3, 5-6, and 8-9 in said figures
subtend the same distance measured along the horizontal base line. Supposing
now that the combustion takes place either at constant temperature or at constant
pressure, then in order to maintain the temperature (or pressure) corresponding
to the point 2 for instance constant until the conditions corresponding to the
point 3 are attained, a more prolonged or energetic combustion and more com-
bustible will be required than is required in order to maintain in a constant
condition the much lower temperature (and pressure) corresponding to the points S
and 9. The necessary variation in the quantity of the combustible admitted to
the chamber g is effected as herein before explained by the longitudinal automatic
displacement of the cam u, which displacement results in a different portion of
the cam surface 5-4 being brought under the cam truck of the cam and con-
sequently enabling the plunger o to move outwards in the direction of the arrow t
to various degrees, thereby regulating the capacity of the chamber and the
quantity of combustible admitted.
An engine constructed in accordance to Diesel and one constructed according to
this invention (referring to the method carried out in Figure 2) ought, with full
load and equal dimensions to compress equally to the same degree and to there-
fore obtain the same diagram. This however is not the case.

page_text: According to this invention I consume during the air compression for the
preparation of the combustible, a portion of this latter together with a portion of
the atmospheric air which is being compressed in g. Thus at the time starting
the working stroke, I have already consumed a portion of the combustion material,
and in the present case therefore, unlike Diesel's method, it is not necessary to
burn the entire charge, and consequently it is not required to compress the air to
the same high degree.
My diagram for full load must therefore be lower than that of Diesel's engine.
The disadvantage as shown in the diagrams which exists in appearance only
with regard to Figure 2 as compared with Diesel's engine is compensated for by
having to deduct from the Diesel diagram the work absorbed by the compressing
pump for the combustion material, which of course is not the case with regard to
my diagram, inasmuch as the compression of the combustible material in my case
is preferably effected by the direct combustion alone thereof. Therefore it will
be clear that my diagram for the arrangement indicated in Figure 2, even with
full load, must be lower than the Diesel diagram to an extent equal to the work
performed by the injection pump used with the Diesel engine.
The compression of the combustible may however be effected either wholly or
partially through combustion, that is to say, if, by closing the valve h as herein-
before explained, I retain in the chamber g exhaust gases under pressure, then
the further compression of the combustible is effected by combustion alone, and
this method I prefer. If, however the valve h is not closed and consequently the
exhaust gases in g are allowed to participate in the full expansion, they will
require, as hereinbefore pointed out, to be again compressed after the expansion,
in which case the compression of the combustible is obviously effected partly by
compression and partly by combustion. I do not however adopt this latter method,
and the above comparison with regard to the Diesel diagram would not of course
hold good if such method were employed.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1. The method of driving explosion engines by compressing air to varying
degrees and then mixing the same with a variable mixture of fresh and exhaust
gases to suit the momentary load on the engine, such mixture being then intro-
duced into the cylinder during an invariable portion of the piston stroke; or the
suction period of the piston may be extended, so as to produce a decrease of air
pressure and thereby prolong the period of combustion.
2. Method of driving explosion engines characterized by the fact that the com-
bustion is divided into two parts in such a manner that the preliminary combustion
is effected in a small auxiliary chamber while the second i.e., the main combustion,
takes place in the engine cylinder itself.
3. A machine for carrying out the method claimed in Claim 1, characterized by
the fact that the air is compressed in a separate air-compressor cylinder from which
it is forced into a chamber and periodically escapes from this latter into a
chamber f, and thence flows or is driven by the displacement of a piston in said
chamber finto second chamberg in which exhaust gases and combustion material
are present, for the purpose of the ignition and partial increase in pressure in this
latter, whereupon, at the moment of the return or out-stroke of the piston, the
mixture of exhaust gases and fuel is introduced owing to the reversing of the
auxiliary pistons o, 2, or piston u¹ from the chamber g into the chamber for into
the cylinder.
4. A machine for carrying out the method claimed in Claim 1, characterized by
the fact that the working engine piston itself, compresses the air and that the lost
space can be varied by a plunger in an auxiliary chamber connected therewith.
5. A machine for carrying out the method claimed in Claim 1, characterized by

page_text: the fact that the working piston itself compresses the air, and that the volume of
air being compressed is rendered variable by an advanced or retarded closing of
the suction valve.
Dated this 13th day of June 1800
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.