Method of and Means for Effecting Ignition and Combustion in Internal Combustion Engines.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Method of and Means for Effecting Ignition and Combustion in
Internal Combustion Engines.
I, RUDOLF DIESEL, of No. 2, Schackstrasse, Munich, Bavaria, Engineer, do
hereby declare the nature of this invention to be as follows:-
-
With a given pressure and given proportions of admixture with air the temper-
ature of ignition of a certain combustible is a constant value, which only depends
upon the physical properties of the combustible. The igniting tenperature is
that temperature up to which the heating of the mixture must be carried under
a definite pressure, for effecting the ignition of the combustible. While however
for a certain combustible the ignition temperature is under definite conditions a
constant value, on the other hand it is of very varying values for different kinds
of combustibles, and this difference can be greatly increased by varying the pres-
sure or proportions of admixture to which the combustible is subject on ignition.
This variation of the ignition temperatures of different combustibles or mix-
tures is practically utilised according to the present invention, for effecting in
combustion motors of all kinds, an ignition of the combustible charges without
any artificial igniting devices for controlling the rate of combustion.
Assuming for example a mixture of gas or combustible vapours and air to be
compressed up to a certain degree of pressure, the temperature of the entire gas
body will be raised by this compression according to a known law.
According to the combustible employed or the proportion of admixture used,
there is a definite degree of compression and corresponding temperature at which
the ignition of the mixture will take place (self ignition); this is the ignition
temperature for that particular combustible under the given circumstances.
As above explained there may exist other combustibles whose ignition tem-
perature is much lower than the above. If therefore the first named mixture be
compressed to such an extent that its temperature remains below the ignition
temperature of its own combustible, but is higher than the ignition temperature
of a second combustible having a lower ignition temperature, then if the second
combustible be injected into the compressed mixture of the first one, an instan-
taneous ignition thereof and consequent combustion of the compressed charge will
be effected.
The rate according to which the combustion proceeds from the moment of igni-
tion is dependent upon the rate according to which the ignition of the igniting
combustible is effected. Thus if for example at the maximum compression of the
charge at or near the dead centre of the compressing piston, the igniting com-
bustible be injected slowly and gradually, a slow spreading of the ignition and a
slow and gradual combustion of the charge will take place.
A nearly instantaneous injection of the ignition combustible will give a corres-
pondingly sudden combustion of the charge, and between these two extremes a
variety of degrees of rapidity of combustion can be obtained.
For carrying out my above described invention various arrangements of the
necessary appliances may be employed.

page_text: Thus a cylinder and piston motor engine provided with the usual inlet valve
for the explosive mixture forming the charges and outlet valve for the combustion
gases, may have a central small igniting valve communicating externally with a
chamber into which either the igniting combustible is directly forced under pres-
sure either in gaseous liquid or spray form, so that on opening the ignition valve,
a jet of the combustible will enter the motor cylinder or the said chamber may
communicate by a pipe with a reservoir into which the igniting combustible is
pumped either alone or together with air, or'air alone or mixed with other gases may
be forced into the reservoir and on its way to the engine chamber it may have a jet
of the igniting fluid injected into it; pulverulent igniting combustibles may also
be injected into the air current in this way.
The compression temperature of the working mixture can also be varied by mix-
ing the charge with a portion of the combustion gases remaining in the cylinder
from the previous charge or by a preliminary heating of the charge by means of
the waste gases or by other means. The compression of the working mixture can
be effected in one or more stages. The inflammability of the ignition combustible
can also be varied by preliminary heating.
4. to-
Dated this 30th day of March 1898.
4.4
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17
ABEL & IMRAY,
Agents for the Applicant..
Method of and Means for Effecting Ignition and Combustion in
Internal Combustion Engines.
I, RUDOLF DIESEL, of No. 2, Schack Strasse, Munich, Bavaria, 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: —
With a given pressure and given proportions of admixture with air the tempera-
ture of ignition of a certain combustible is a constant value, which only depends
upon the properties of the combustible employed; on the other hand such tem-
perature of ignition is of very varying value for different kinds of combustibles
and this difference can be greatly increased by varying the pressure or proportions
of admixture to which the combustible is subject on ignition.
This variation of the ignition temperatures of different combustibles or mixtures
is practically utilised according to the present invention, for effecting in internal
combustion motors an ignition of the combustible charges without employing any
artificial igniting devices and for controlling the conditions under which com-
bustion takes place, and its duration, or in other words, the form of the combustion
curve in the indicator diagram. When a mixture of gas or combustible vapours
and air is compressed the temperature of the entire gas mixture will be raised
by this compression, and according to the combustible employed and the propor-
tions of admixture used, there will be a definite degree of compression and
corresponding temperature at which the spontaneous ignition of the mixture will
take place this temperature may be termed the ignition temperature for that
particular combustible under the given circumstances.
If now a charge of such a mixture be compressed to such an extent that its
temperature remains below its ignition temperature but is equal to or higher than
the ignition temperature of a second combustible having a lower ignition tempera-
ture, then if the second combustible be injected into the said compressed mixture,

page_text: t will be ignited thereby and will consequently effect the combustion of the com-
ressed charge.
The conditions under which the combustion of the charge will proceed and its
luration are affected by and dependent upon the manner in which the injection
of the igniting combustible is effected, so that by regulating this by means of any
suitable known mechanical devices, the performance of the motor engine can be
correspondingly varied.
Thus referring to the diagram at Fig. 1 of the accompanying drawing, if the
line ab represent the compression curve of the less readily ignitable mixture, and
if at the maximum compression of the charge, at or near the dead centre b of the
piston, the more readily ignitable combustible be introduced slowly and gradually,
a slow spreading of the ignition and a slow and gradual combustion such as is
If on the other hand the igniting mix-
represented by the curve bel will ensue.
ture be introduced almost instantaneously, a correspondingly sudden combustion
of the charge, such as according to the line be will be produced, and between these
two extremes a variety of degrees of rapidity of combustion can be obtained such
as are represented by the curves be², be³ &c.
For carrying out my above described invention various arrangements of the
necessary appliances may be employed. Thus referring to the sectional diagram
Fig. 2, C-and P are cylinder and piston of a motor engine provided with the usual
inlet valve E for the air and combustible mixture forming the charges, and outlet
small injection valve com-
valve A for the combustion gases; at D is provided
municating externally with a chamber D¹ into which the igniting combustible
may either be directly forced under pressure either in gaseous, liquid, or spray
form, so that on opening the injection valve, a jet of the igniting combustible will
enter the motor cylinder; or the said chamber D¹ may communicate by a pipe S
with a reservoir L into which the igniting combustible is pumped at m either
alone or together with air; or air alone or mixed with other gases may be forced
into the reservoir L and on its way to the engine chamber it may have a jet of
the igniting fluid injected into it by an injecting device at T. Pulverulent igni-
ting combustibles may also be injected into the air current in this way. For this
purpose the device T may be provided with a revolving plug with a cavity that
is first filled with a definite quantity of combustible from T and then discharges
the same into the air or gaseous mixture flowing through pipe S to chamber D¹.
The duration of the opening of the valve D, that is, the admission period of the
igniting combustible, and the degree of pressure existing in the chamber D¹ or
in the reservoir will determine the form of the resulting combustion curve.
The compression temperature of the working mixture can also be varied by
mixing the charge with a portion of the combustion gases remaining in the cylin-
der from the previous charge or by a preliminary heating of the charge by means
of the waste gases or by other means. The compression of the working mixture
can be effected in one or more stages. The inflammability of the igniting com-
bustible can also be varied by preliminary heating.
The resrvoir L is provided with a safety valve R, the load on which can be
adjusted as may be required by shifting the sliding weight B thereon by means
of suitable gear Q.
The mechanism for working the valves A. E and D may be of any suitable
known arrangement and need not be farther described.
It will be readily understood that a great variety of combustibles and com-
bustible mixtures can be employed for carrying out my said invention, thus for
the combustible charges may be used a mixture of air and either Dowson gas,
blast furnace gas, or ordinary illuminating gas, (the latter however only in small
proportion to the air) all of which can be compressed to a high degree without
spontaneous ignition.
For the igniting combustible can be employed benzine, petroleum, alcohol, very
rich illuminating gas, or acetylene, either in liquid, gaseous or spray form, or
mixtures of these with air may be used.

page_text: Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I declare that what I claim is :-
1. Method of effecting ignition and combustion in internal combustion engines
consisting in compressing the combustible charge to a degree below that at which
it attains its ignition temperature and then forcing into such charge another com-
bustible having a lower ignition temperature, such that it becomes ignited by the
heat of the compressed charge and thereby effects its combustion, substantially as
described.
2. In internal combustion engines operating with compressed combustible
charges, the use of means for injecting into the engine cylinder at or about the
end of the instroke, a combustible that will become ignited by the heat produced
by the compression of the combustible charge, and will thereby effect its com-
bustion, substantially as described.
Dated this 14th day of December 1898.
ABEL & IMRAY,
Agents for the Applicant.