-

1. * GB780023 (A)
Description: GB780023 (A) ? 1957-07-31
New or improved combustion process for internal combustion engines with
subdivided combustion space
Description of GB780023 (A)
PATENT SPECIFICATION
Date of Application and filing Complete Specification: May 25, 1955.
Application made in Germany on May 25, 1954.
780,023 No, 15087/55.
Complete Specification Published: July 31, 1957.
Index at acceptance:-Classes 7(2), B2C(1A:1C:9:15A); and 7(3),
B2J(2:4A:4C2:4C3:
4D:19B:20).
International Classification:-FO2b, f.
COMPLETE SPECIFICATION
New or Improved Combustion Process for Internal Combustion Engines
with Subdivided Combustion Space I, WALTER PFLAUM, of 9,
Hermannstrasse, Berlin-Wannsee, Germany, a German citizen, do hereby
declare the invention, for which I pray that a patent may be granted
to me, and the method by which it is to be performed, to be
particularly described in and by the following statement: -
The advantages of an internal combustion engine with a subdivided
combustion space are generally known. In particular, a chamber divided
off from a main combustion space may be used asapre-combustionchamber
or as a turbulence chamber. In the case of a pre-combustion chamber,
the fuel is injected into such chamber and partially ignited and
consequently blows the rest of the fuel into the main combustion space
with increase in pressure, the main combustion then taking place. In a
turbulence chamber, all or nearly all the combustion air is forced
into the chamber wherein it is caused to rotate by the action of a
tangential transfer duct or other means, the fuel being injected into
the rotating air mass.
In all cases, favourable combustion depends upon the co-operation of a
number of factors, whereof the most important are:The form and

2. position of the fuel stream admitted, the form and disposition of the
chamber and of any air or mixture turbulence therein, and the
temperatures in the chamber and of the wall enclosing the same.
The interaction between these factors is so great that successful
development can be ensured only if they are suitably co-ordinated.
Thus, the ignition and combustion and the air or gas movement are so
affected by the temperature of the wall of the chamber that the fuel
stream and air movement, for example, have to be differently
determined in order to produce the most favourable conditions with
different temperatures of the chamber wall.
Measures serving to ensure a certain tem.
perature of the chamber are usually adopted.
[Price 3/61 In particular, use has been made for this purpose of
inserts embodying either the transfer duct between the main combustion
space and the chamber or part or all of the walls of the said chamber.
Such inserts have 50 also been insulated, or the walls of the chamber
or cooling-water jacket have been suitably dimensioned in order to
keep the temperature of the chamber wall at a certain value. However,
such measures only allow 55 favourable conditions to be assured for a
certain load, whereas, under other load conditions, the wall
temperature may be either too low or too high, which may be
disadvantageous with respect to combustion, power 60 output, fuel
consumption, smokeless combustion and combustion noise.
In contrast with the foregoing, the present invention enables the
individual factors to be more favourably co-ordinated, so that better
65 and more uniform combustion of the fuel is ensured.
According to the invention, in a combustion process for an internal
combustion engine with a chamber divided from the main combustion
space, particularly but not essentially a pre-combustion chamber or a
turbulence chamber, combustion air is caused to execute a rotary
movement in the said chamber, fuel is injected into the rotating air,
and the temperature of the wall of the said chamber is automatically
controlled by heating the said wall in controlled dependence upon an
operating condition of the engine.
The temperature of the wall of the chamber may be controlled in
dependence on engine speed, power output or torque or on the
temperature of the engine, for example by means of a
temperature-responsive device, which may be a thermostat in the
cooling 85 system of the engine or in the exhaust or the like. If
desired, provision may in addition be made for cooling the wall of the
chamber.
Electrical energy may be used for heating the chamber and a resistance
wire or high 90 780,023 frequency current may be used for the purpose.
Or an external source of heat for a fluid heating medium may be used,

3. permitting heating not only during running but also during engine
starting, or the engine coolant itself may be utilised. A fluid medium
may also be chemically heated or cooled, or such heating or cooling
may be effected by mechanical means such as a compressor or
compression-expansion refrigerator.
The rotary air movement, provided in accordance with the invention in
conjunction with the heating of the chamber wall, ensures that
practically all the air comes uni15formly into contact with the wall,
so that almost uniform heating of the turbulent air mass rotating in
the chamber can be attained and high efficiency achieved.
By the injection of the fuel into the rotating and uniformly heated
air, relatively uniform combustion conditions are obtained at all
points in the chamber, so that, with a uniform air-fuel mixture, good
combustion is attained. The fuel also is brought directly 25into
contact with the heated walls of the chamber.
In a particularly advantageous construction of engine, the transfer
duct between the chamber and the main combustion space is formed in a
manner known per se by obliquely or helically directed apertures which
produce the rotating air movement in the said chamber. The axis of the
fuel stream is preferably disposed in or substantially in the
direction of the axis of rotation of the air.
Thus, a twist is imparted not only to the air flowing into the
chamber, but also to the gases flowing out of the same, which assists
further mixture formation and completion of the combustion.
The obliquely or helically directed apertures of the transfer duct may
all be the same or may differ in size, shape and/or direction.
Further details and advantages of the invention may be gathered from
the following description of various examples described with reference
to the accompanying drawings, wherein:Fig. 1 is a vertical axial
section through the upper part of an internal combustion engine having
a pre-combustion chamber arranged to one side of the axis of the
engine cylinder:
Fig. 2 is a vertical section showing a modified construction of the
pre-combustion chamber; Fig. 3A is a developed peripheral section,
drawn to a larger scale, through the transfer duct between the
cylinder space and the precombustion chamber of Figs. 1 and 2; Fig. 3B
is a plan view, also to a larger scale, of the insert forming the
transfer duct in Figs. 1 and 2; Figs. 4A and 4B show a variant of
Figs.
3A and 3B; Fig. 5 shows a further variant of Figs. 3A and 4A; Fig. 6
is a vertical axial section of the upper part of an internal
combustion engine with a further modified pre-combustion 70 chamber;
Fig. 7 is a section along the line A, B. C, D in Fig. 6; Fig. 8 is a
small scale plan view of a multicylinder engine constructed in

4. accordance 75 with Figs. 6 and 7: and Fig. 9 is a plan view
corresponding to Fig.
8 of a somewhat different construction of the engine.
In Fig. 1, a pre-combustion chamber 11 is 80 arranged in the cylinder
head 10 to the side of the axis of the cylinder. The chamber 11 of
this e:-ample is cylindrical with the longitudinal axis disposed
vertically. A fuel injection nozzle may enter through the cover 85 of
this chamber in alignment with the said axis.
The transfer duct 12 between the precombustion chamber 11 and the main
combustion space 13 over the piston 14 is formed 90 by an insert 15,
individual transfer apertures 16 in such insert 15 being obliquely
positioned or helically directed about the jet axis of the injection
nozzle in order to impart a rotating movement to the combustion air 95
passing through such apertures into the chamber 11 from the cylinder
during the compression stroke. At the same time, the fuel is carried
towards the wall of the chamber 11, more particularly by centrifugal
action, so that the wall temperature can have a direct effect on the
fuel.
The apertures 16 may be uniformly dimensioned, arranged and directed,
as illustrated in Figs. 3A and 3B. If desired. however, the 105
distribution and the shape or direction of the apertures 16 can be
varied in accordance with the position of the pre-combustion chamber
in relation to the main combustion space and the shape of such
chamber. Thus, for 110 example, Figs. 4A and 4B show apertures 16a
with cross-section of differing sizes decreasing or increasing in
sequence around the circle, while in the case of Fig. 5 the apertures
16b have not only different cross-sections but 115 also different
angles of inclination to the horizontal. The radial shaping of the
apertures of a transfer duct can also be different from one another,
or individual apertures of different kinds can be provided separately
120 or in combination, the apertures being, for example, distributed
regularly around the periphery or following a particular expedient
law. Furthermore. the axis of the circular arrangement of apertures
need not coincide with the axis of the pre-combustion chamber 11,
because the said apertures may be arranged eccentrically or in any
other desirable way in the insert 15.
A conductor spiral 17 (Fig. 1), protected 130 780,023 against the
effect of the cooling jacket space in the cylinder head by an
insulating mass 18, is disposed around the chamber 11 for the purpose
of attaining the controlled wall temperature thereof. The spiral can
be an electric heating resistance or a spiral tube supplied from
outside with a hot medium. The said medium may be a fluid heated by
suitable means. The walls of the spiral may entirely or partially
cover the wall of the chamber 11.

5. The heating is controlled so that the temperature of the whole or part
of the wall of the chamber 11 is controlled in dependence upon an
operating condition of the engine.
Fig. 2 shows a modification wherein the chamber 11 is completely
enclosed by a onepiece insert 19 in the bottom of which are formed the
apertures constituting the transfer duct. The insert 19 is so
dimensioned that a space 20 intervenes between its exterior and a
surrounding wall of the cylinder head. This space 20 is used for
accommodating a spiral electric wire 21 or a spiral tube. A
heat-insulating layer also may be provided in the space 20, as shown.
If desired, the spiral could be dispensed with and a heating medium
could be allowed to flow directly through the intermediate space 20.
The heating is controlled so that the temperaSo ture of the whole or
part of the wall of the chamber 11 is controlled in dependence upon an
operating condition of the engine.
While the examples above described involve heat transfer means for
heating the wall of the chamber 11, the heating may also be effected
in a manner known per Se by direct high-frequency current.
Figs. 6 to 9 show constructions in which the chambers are turbulence
chambers, generally of spherical or globular form. In most
turbulence-chamber engines, the fuel is injected transversely through
the rotating air mass and thus substantially perpendicularly to the
axis of the whirl in the turbulence chamber, for example in the
direction 22 or 23 in Fig. 6. This causes the fuel jet or stream to be
cut by the air streams both at its foot and at its head, or both at
its point of egress from the chamber and at its point of entry.
However, this makes fuel distribution so non-uniform that optimum
mixture formation and maximum power output, and thus the lowest
possible fuel consumption, cannot be attained. For this reason, the
fuel 55is preferably injected in the direction of the axis 24 of the
air whirl or parallel to such axis as illustrated by way of example in
Figs.
6 and 7. The turbulence chamber 25 then communicates with the main
combustion space 27 via a transfer duct 26 communicating tangentially
or substantially tangentially therewith. The injection nozzle is
inserted at 28 into the socket member 29 in the direction of the axis
24.
As with the examples described with reference to Figs. 1 and 2,
particularly complete mixture formation is also attained with the
construction in Figs. 6 and 7, more particularly because those fuel
particles which are carried to the wall of the chamber 25 encounter,
because of the controlled wall temperature, just that temperature
condition which is advantageous for the intended favourable course of
combustion.

6. The turbulence chamber may be either 75 spherical or of any flattened
or oblate form.
It is also immaterial whether the said chamber is accommodated in the
cylinder head, in the engine cylinder itself, or in a separate
intermediate member or extension of the 80 cylinder. It is sufficient
if the air whirl can be formed and thereafter maintain its kinetic
energy.
As regards heating, the same applies to the construction according to
Figs. 6 and 7 as to 85 Figs. 1 and 2, so that there is no need for a
further special explanation in this connection.
A heating spiral 30 corresponding to Fig. 1 is illustrated by way of
example, and is embedded in insulating material. However, any 90 other
kind of heating means can be provided.
Furthermore, Fig. 8 shows a construction wherein a space 32 is
provided between individual cylinder heads 31 of an engine, in which
space the injection nozzle 33 or the 95 head of same can be detachably
fitted; without the cylinder heads 31 having to be removed for this
purpose.
In cylinder heads used in blocks, as shown for example in Fig. 9, a
recess 34 with the 100 axis of the fuel injection nozzle inclined in
relation to the axis of the engine is expedient in certain
circumstances. This arrangement is naturally not limited to either the
one or the other cylinder head construction. 105 The turbulence
chamber 25 is advantageously so displaced in relation to a transverse
plane passing through the cylinder axis that the axial directions of
the air turbulence and the fuel stream extend substantially parallel.
It 110 is also expedient in this case accordingly to displace the
inlet and exhaust valves 36 and 37 respectively as illustrated.
The invention is not limited to pre-combustion chambers or turbulence
chambers, 115 but is applicable to all kinds of subdivided combustion
spaces. Thus, the combinations of rotary air movement and wall heating
may also be of advantage on engines having a socalled air accumulator,
that is a separate air 120 chamber into which combustion air flows
from the main combustion space during the compression stroke and from
which it flows out during the expansion stroke, in such engines, the
fuel nozzle is not located in the 125 separate chamber, but the nozzle
can be arranged so that, as required by the present invention, at
least a part of the fuel is injected by the nozzle into the said
chamber. Uniform heating of the combustion air exerts a favour780,023
able influence on the combustion of the fuel in this case also. The
production of rotary air movement is of advantage not only for the
inflow of the air into the separate chainber, but also for its
outflow, as it contributes to better mixture distribution and to
better continuation and completion of the mixture formation and

7. combustion in the main combustion space. The process according to the
invention is thus also of use when there is only partial combustion in
the separated chamber.
In addition to provision for automatically controlled heating of the
wall of the chamber, provision may be made also for cooling the said
wall by a cooling medium, for example by supplying the spiral tube,
referred to in connection with Figs. 2, 6 and 7, with a fluid cooled
by suitable means. Alternatively, if the spiral is dispensed with, as
referred to in connection with Fig. 2, the cooling medium could be
allowed to flow directly through the intermediate space 20.
A suitable heating and cooling combination would consist, for example,
of electric heating and cooling by a flowing liquid coolant. The space
around the chamber wall will generally afford enough room to
accommodate provision for both heating and cooling.
With provision for cooling as well as heating., the chamber wall may
be heated at times, for example on starting of the engine, and cooled
at other times, for example when the engine is running under heavy
load.
In some cases, depending upon the dimensions and disposition of the
chamber, provision may be made, for the purpose of more effectively
controlling the temperature of the chamber wall, not only for heating
the said wall in one part but also for cooling it in another part at
the same time.
Also in cases in which provision is made for cooling as well as
heating, it is arranged that the wall temperature is controlled in
dependence upon an operating condition of the engine
* Sitemap
* Accessibility
* Legal notice
* Terms of use
* Last updated: 08.04.2015
* Worldwide Database
* 5.8.23.4; 93p