Improvements in Regulating Fuel Supply for Slow Combustion Motors, and Apparatus for that Purpose.
Year: 1895

page_text: Date of Application, 27th Feb., 1895-Accepted, 27th Apr., 1895
Improvements in Regulating Fuel Supply for Slow Combustion
Motors, and Apparatus for that Purpose.
1, RUDOLF DIESEL, of 153 Kant Strasse, Charlottenburg, Prussia, 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 :--
The regulation of the fuel supply of combustion motors has hitherto been
conducted in one of two ways which may be understood from the indicator
diagrams Figs. 4 or 5. In Fig. 4 p indicates the pressure of the entering fuel,
oab the variable duration of the admission. In
Fig. 5 ppp indicate the explosion pressure, which can be varied by altering the
proportions of air and fuel mixture.
and o ab
....
oabl
Thus the first regulation takes place at constant pressure, the second at constant
volume. The new method of regulating supply, hereinafter described, differs
completely from both the foregoing as it alters the form or shape of the combustion
curve according to the diagramn Fig. 6. The curve 2-3 is the period of com-
bustion, during which fuel is introduced, at a higher pressure than the highest
compression pressure at point 2. If a certain excess of pressure produces the
definite curve of combustion 2-3, when the pressure is less a deeper curve 2-31
is produced, when it is greater higher curves 2-3", 2-3 are produced, so that
also the succeeding expansion curve 3-4, and therefore the area of the diagram
is altered. Fig. 6 shews that to carry out this method two conditions must be
observed: (1) The length or duration of the fuel admission must be variable, so
as to influence the length of curve 2-3 or 2-3 etc. (2) The excess fuel pressure
must be variable, so as to alter the position or form of the combustion curve.
Fig. 1 shews apparatus for carrying out this regulation of supply with powdered
solid fuel. C is the cylinder with piston P and air valve V. D is the nozzle for
fuel supply, which determines the period of fuel admission and consequently the
length of the curve 2-3, 2-3' etc. in Fig. 6, by the needle valve n worked by
known mechanism (described in the Specification No. 7241 of 1892) where also is
described the funnel T, with the operated valve r for admitting coal dust.
tube S connects the nozzle D and the coal dust supply with the receptacle L,
which by means of a special pump and pipe m, is fed with combustible gas, or
with a mixture of gas and air, or it may be with pure air, always at a higher
pressure than the highest compression pressure in the cylinder.
The
During the opening of the needle valve n, the gas, or the mixture, in consequence
of the excess of pressure, flows through the nozzle D into the compression space K
of the cylinder, carrying with it the coal dust supplied on the way by r, and
dispersing it through it causing a more rapid and perfect combustion than if the
powder were directly sent into the cylinder. If the pressure in receptacle L,
were fixed once for all, the same combustion curve 2-3 (Fig. 6) would always
result.
But if by variable action of the engine the shape of the combustion curve is to
be altered, then the pressure in receptacle L must be subjected to a regulating
influence, which is attained by means of the safety valve R (Fig. 1) the load B of
which can be altered by means of the rod of the governor so that the pressure

page_text: in L shall always correspond to the load on the safety valve. Thus there is
besides variation of the period of fuel admission, the new feature of simultaneously
varying the pressure of the stream of combustible. Both variations conjointly
produce the variable form of the combustion curve, distinctly marking the new
method of regulating. Both can be effected by the governor, or one by the
governor, the other, by hand, according to the degree of sensitiveness required.
Instead of the weight B a spring can also be applied to valve R; the pressure
regulation can also be applied as desired to the pump feeding the tube m; this
latter method would be adopted should fluid fuel be exclusively used, in which case
the receptacle L, would act as the pressure vessel of the pump.
The coal supply apparatus might be placed directly on the receptacle L, as the
motion of the gas therein would keep the dust in suspension. The funnel T might
also contain fluid fuel.
Further, the mixture might first take place inside the cylinder. The receptacle
would, in this case, contain pure air, and, according to Fig. 2, in addition to the
nozzle for solid fuel D, a concentric nozzle d, for fluid or gascous fuel is provided
to intensify the combustion.
Instead of being concentric, the nozzles, as shewn in Fig. 3, might be arranged
side by side leading into a special combustion chamber by a perforated partition.
To ensure perfect combustion, a thorough mixture of the entering stream of fuel
with the air in the compression space is of special importance. For this purpose
the supply apparatus described can be provided as shewn in Fig. 7 with a mixing
appliance M which subdivides the jet in the compression space and diffuses it
thoroughly therein.
The distributor M may be a simple perforated tube, or a rose hemispherical
as M or of disc or star form as M², placed at different parts of the chamber, or,
for mixing a dispersing nozzle M³, or an injector M' would answer.
Instead of employing such distributors, thorough mixture might be obtained by
arrangement of the combustion chamber, as in Fig. 11, where by lengthening the
tube the stream of combustible enters at E, so that, during the stroke of the
piston from 1 to 11 most of the air is forced to pass over the inlet E, the fuel
escaping radially or upwards producing a regular counter current.
There might also be a second nozzle at O.
Fig. 12 shews an arrangement according to which the fuel is not introduced
from above but from the side, and by which the left hand ribs R R force the air
during its expansion from the chamber into the cylinder to pass over the inlets.
These ribs might also be attached to the piston, as at R' on the right, so that by
the motion of the piston a foscible mixture of the gases is effected.
Further, thorough mixture might be obtained by the nozzle itself being moved
along with the piston; as in Fig. 13.
The nozzle might be fixed to the piston and the fuel might be supplied through
the hollow piston rod.
Figs. 7 to 10, shew another way of carrying out the above described method of
regulation, the use of a special air pump being dispensed with; here the motor
piston itself compresses the air necessary for regulating supply not in the usual
way by the momentum of the fly wheel after cessation of combustion but during
the normal process of working, without interrupting combustion, as an integral
part of the working process itself.
In Figs. 7 and 8 Y is a valve through which during the regular working, a
small quantity of compressed air escapes at the end of each compressing stroke of
the piston and passes by the tube 1, Figs. 7 and 8, iuto the receptacle L. The air
pressure in the reservoir therefore equals the highest compression pressure in the
cylinder, but according to the process described, an excess of pressure for injection
of the fuel is required. To obtain this result, the fuel nozzle is not to be opened
till the piston has slightly receded from the dead point, that is to say, till the
pressure in the cylinder has become somewhat lessened.

page_text: As the opening of the nozzle by the governor occurs sooner or later, so the
excess of pressure in the receptacle I, varies.
The injection of the fuel takes place as described, S Fig. 7 being the connecting
tube between the receptacle L, and the nozzle as in Fig. 1.
The valve Y can also be arranged to be opened at the end of the stroke by the
piston itself, or it might be a self acting relief valve, or for it might be substituted
a cock or slide valve.
In the arrangement shewn in Figs. 7 and 8 where the valve Y is worked,
Figs. 8 and 10 shew the details of this working gear. W is here the weigh shaft
with a number of cams I to V. Cani II Fig. 9 works valve Y in normal working.
Cam I works the fuel valve for nozzle D, and cam IV works the principal
valve of the motor. The whole of this gear serves also in the reverse order to
start the motor, compressed air passing through valve Y from L into the cylinder
to drive the piston, and then escaping through the principal valve V.
During this very short starting period the lever H, Fig. 9, takes the dotted
position H', so that the valve Y is moved by cam I instead of II, the principal
valve V by cam IV instead of V, while the fuel cam III is disengaged.
After a few revolutions made in this manner, the motor has attained its normal
speed; at this moment the pin p which retains the lever H in position, is removed,
the lever is automatically pushed by a spring F to the normal working position H,
carrying with it the system of cams to continue the normal working without
interruption. As the moving of the cams has to occur at the exact moment, it can
only take place when a specially arranged notch in the cam shaft receives the
catch p Figs. 9 and 10.
The valve Y in Fig. 7 serves three purposes; (1) to start the motor with
compressed air (2) to fill the receptacle L during normal work (3) to operate as
safety valve being loaded by a spring 1, so that on explosion in the cylinder the
gases can pass to L and thence through the safety valve R to the atmosphere. To
determine the maximum pressure in the cylinder and consequently that in the
receptacle La hand wheel H (Figs. 7 and 8) is applied, by turning which the
loading spring can be more or less compressed, and either while the engine is
stopped or going.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. Regulation of combustion motors according to which variation of the action is
effected by varying the form of the combustion curve, that is by blowing a simple
or compound stream of combustible into the compression space of the engine under
varying excess of pressure and varying duration of the fuel supply.
2. The thorough mixture of the fuel supplied according to Claim 1 with the air
in the compression space of the engine by means of subdivided inlets or by special
distributors or injectors, or by so arranging the compression space that the mixture
results from the flow of the air over the inlets for combustible or by means of
stationary guide ribs, or moveable mixing blades, or by arranging moveable inlet
nozzles.
3. The automatic production of the compressed air necessary for operating
according to Claim 1, by the working piston during its normal action, without
interfering with the combustion process, during part of the compression stroke,
whereby the necessary excess of pressure results in such manner that the fuel
supply only begins a longer or shorter time after commencement of the working
stroke of the piston.
4. The use of the combination necessary for fuel supply according to Claim 1
in reversed order, for starting the engine by adding to the valve gear other cams,
spring and catch, whereby the alternation of the gear from the starting to the
working position is effected at the right place and automatically as soon as the
engine has attained its speed.

page_text: 5. The combination of starting, feeding, and safety valve with variable load for
exact determination of the degree of compression and of the pressure in the
compressed air receptacle according to Claim 1.
Dated this 27th day of February 1895
ABEL & IMRAY,
Agents for the Applicant.