U.S. patent application number 10/546956 was filed with the patent office on 2006-09-28 for nozzle for spraying liquid fuel.
Invention is credited to Christian Backer, Stefan Kunz, Florian Metz, Markus Neumuller, Chrisitne Sallinger.
Application Number | 20060214030 10/546956 |
Document ID | / |
Family ID | 32913724 |
Filed Date | 2006-09-28 |
United States Patent
Application |
20060214030 |
Kind Code |
A1 |
Neumuller; Markus ; et
al. |
September 28, 2006 |
Nozzle for spraying liquid fuel
Abstract
A nozzle for atomization of liquid fuel by air flowing through
the nozzle (20), with an air entry area (50), an air exit area (52)
and a flow path (54) which connects the air entry area (50) to the
air exit area (52), the nozzle (20) being made of ceramic material,
an air guidance device (56) being provided in the air entry area
(50) which imparts a swirl to the inflowing air, and the air
guidance device (56) being an integral part of the nozzle (20).
Furthermore, there is a heater (10) equipped with such a nozzle
(20) for mobile applications.
Inventors: |
Neumuller; Markus;
(Hechendorf, DE) ; Backer; Christian;
(Furstenfeldbruck, DE) ; Sallinger; Chrisitne;
(Unterschleissheim, DE) ; Kunz; Stefan; (Munchen,
DE) ; Metz; Florian; (Mering, DE) |
Correspondence
Address: |
ROBERTS, MLOTKOWSKI & HOBBES
P. O. BOX 10064
MCLEAN
VA
22102-8064
US
|
Family ID: |
32913724 |
Appl. No.: |
10/546956 |
Filed: |
February 28, 2003 |
PCT Filed: |
February 28, 2003 |
PCT NO: |
PCT/DE03/00666 |
371 Date: |
August 26, 2005 |
Current U.S.
Class: |
239/463 ;
237/12.3R; 431/353 |
Current CPC
Class: |
F23D 2212/10 20130101;
F23D 11/107 20130101 |
Class at
Publication: |
239/463 ;
237/012.30R; 431/353 |
International
Class: |
F23C 7/00 20060101
F23C007/00; F24J 3/00 20060101 F24J003/00 |
Claims
1. Nozzle for atomization of liquid fuel by means of air flowing
through a nozzle (20) with an air entry area (50), an air exit area
(52) and a flow path (54) which connects the air entry area (50) to
the air exit area (52), characterized in that the nozzle (20)
formed of ceramic material, that, in the air entry area (50), there
are air guidance elements (56) which are adapted to impart a swirl
to the inflowing air, and that the air guidance elements (56) are
formed as an integral part of the nozzle (20).
2. Nozzle as claimed in claim 1, wherein the nozzle (20) has means
(58) for holding a glow plug (62).
3. Nozzle as claimed in claim 1, wherein the nozzle (20) has, at
least in part, an essentially cylindrical shape and wherein the air
guidance elements (56) form channels (60) which are offset with
respect to radial directions.
4. Nozzle as claimed in claim 1, wherein the air guidance elements
(56) have essentially triangular base surfaces and rounded
corners.
5. Nozzle as claimed in 1, wherein the air guidance elements (56)
are blades.
6. Nozzle as claimed in claim 2, wherein the means for holding the
glow plug (62) is a hole (58) which runs obliquely to a center axis
of the nozzle.
7. Nozzle as claimed in claim 2, wherein an at least essentially
cylindrical part of the nozzle (20) has an essentially cylindrical
shoulder (64) with an increased diameter and wherein the means for
holding the glow plug (62) is a hole (58) which penetrates the
shoulder (64) and which runs obliquely to a center axis of the
cylindrical part.
8. Nozzle as claimed in 1, wherein an at least essentially
cylindrical part of the nozzle (20) has an essentially cylindrical
shoulder (64) with an increased diameter and wherein the
cylindrical shoulder (64) has recesses (66) for holding mounting
pins (68).
9. Nozzle as claimed in claim 1, wherein the nozzle (20) is a
Venturi nozzle.
10. Heater (10) for mobile applications, especially motor vehicles,
with a burner (12) for combustion of a fuel/air mixture, the burner
(12) having a nozzle comprising: an air entry area, an air exit
area and a flow path which connects the air entry area to the air
exit area, wherein the nozzle is formed of ceramic material, in the
air entry area, there are air guidance elements which are adapted
to impart a swirl to the inflowing air, and the air guidance
elements are formed as an integral part of the nozzle.
11. Heater as claimed in claim 10, wherein the nozzle has means for
holding a glow plug.
12. Heater as claimed in claim 10, wherein the nozzle has, at least
in part, an essentially cylindrical shape and wherein the air
guidance elements form channels which are offset with respect to
radial directions.
13. Heater as claimed in claim 10, wherein the air guidance
elements have essentially triangular base surfaces and rounded
comers.
14. Heater as claimed in claim 10, wherein the air guidance
elements are blades.
15. Heater as claimed in claim 11, wherein the means for holding
the glow plug is a hole which runs obliquely to a center axis of
the nozzle.
16. Heater as claimed in claim 11, wherein an at least essentially
cylindrical part of the nozzle has an essentially cylindrical
shoulder with an increased diameter and wherein the means for
holding the glow plug is a hole which penetrates the shoulder and
which runs obliquely to a center axis of the cylindrical part.
17. Heater as claimed in claim 10, wherein an at least essentially
cylindrical part of the nozzle has an essentially cylindrical
shoulder with an increased diameter and wherein the cylindrical
shoulder has recesses holding mounting pins.
18. Heater as claimed in claim 10, wherein the nozzle is a Venturi
nozzle.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of Invention
[0002] The invention relates to a nozzle for atomization of liquid
fuel by means of the air flowing through the nozzle, with an air
entry area, an air exit area and a flow path which connects the air
entry area to the air exit area.
[0003] 2. Description of Related Art
[0004] Generic nozzles are used, for example, in vehicle heaters.
These vehicle heaters can be used, for example, as auxiliary
heaters and/or stationary heaters.
[0005] The nozzle is used to supply combustion air, due to the flow
of combustion air the liquid fuel, for example, diesel or gasoline,
being entrained from a fuel nozzle and atomized. In this way, a
mixture of combustion air and fuel is obtained which can be burned,
optionally, after mixing with air supplied on other flow paths, by
which the heat necessary for heating operation is produced. This
heat generated by a burner then heats a heat transfer medium, for
example, water or air.
[0006] Nozzles of the prior art often are made of metal, e.g. as
cast parts or turned parts. The disadvantage in these components is
the comparatively high production cost and the generally high
thermal conductivity of the metals. The thermal conductivity can
pose problems when the temperature in the area of the fuel nozzle
rises unduly as a result of the heat produced in the burner. To
solve the problems which are associated with metallic nozzles, it
has been proposed that a ceramic nozzle be used.
[0007] The flow behavior of the combustion air is important for the
mixing of the combustion air with the fuel on the common path. In
order to improve the flow behavior of the combustion air, it was
already proposed in DE 100 39 152 A1 and corresponding U.S. Patent
Application Publication 2003/0022123 A1 that a swirl be imparted to
the combustion air. In this way, it is possible to distinctly
improve the atomization quality and thus the efficiency of the
burner, since the combustion air speed is increased as a result of
the pronounced tangential component of motion. In order to impart
this swirl, a carrier with swirl blades is connected upstream of
the input area of the nozzle. However, the disadvantage in this
carrier with upstream swirl blades is that an additional component
is needed, for which reason the tolerances which exist for
undisturbed operation of the nozzle can sometimes be exceeded.
[0008] In heaters of the prior art it is, furthermore,
problematical to maintain narrow tolerances with respect to
positioning of the glow plug with regard to the inflowing fuel/air
mixture.
SUMMARY OF THE INVENTION
[0009] The object of the invention is to make available a nozzle
which can be economically produced, which has thermal conductivity
which is low compared to metal, and which induces advantageous
properties with respect to the flow behavior of the combustion air,
and calibration problems are to be avoided.
[0010] This object is achieved by the nozzle being made of ceramic
material and having an air guidance means formed as an integral
part thereof in the air entry area so as to impart a swirl to the
inflowing air
[0011] The invention is based on the generic nozzle in that the
nozzle is made of ceramic material and the air entry area has air
guidance means which impart a swirl to the inflowing air but
improves thereon by the air guidance means being made as an
integral part of the nozzle. In this way a nozzle is provided which
can be economically produced. The ceramic material can be easily
worked, numerous versions with respect to shaping being possible.
In particular, the air guidance means which delivers a swirl to the
combustion air outside of the air entry area can be made integrally
with the nozzle. As a result of using a ceramic, there is the
additional advantage that the area of the nozzle around the fuel
needle which is located in the nozzle does not assume overly high
temperatures, so that amounts of fuel which may be emerging from
the nozzle cannot ignite. The integral execution of the air
guidance means makes it possible to easily adhere to tolerances,
since miscalibration of the air guidance means when the burner is
being assembled is no longer possible.
[0012] The invention is advantageously developed in that the nozzle
has means for holding a glow plug. The positioning of the glow plug
with respect to the nozzle is an important parameter with regard to
good starting behavior of the burner. In heaters of the prior art,
the glow plug was generally held by the burner housing, so that, in
this way, fluctuations of the positioning with respect to the
nozzle could occur. These tolerances can be precluded by the
property of the nozzle of the present invention in that the nozzle
itself has means for holding the glow plug so that the glow plug
always has the same position with respect to the nozzle.
[0013] Furthermore, the nozzle in accordance with the invention is
advantageously developed in that the nozzle has at least in part an
essentially cylindrical shape and that the air guidance means forms
channels which are offset with respect to the radial directions.
The air which is flowing in perpendicular to the axis of the nozzle
is therefore not radially supplied, but supplied with an offset.
This offset determines the swirl which is delivered to the
combustion air, and thus, the flow behavior and ultimately also the
properties and quality of combustion.
[0014] It is especially useful for the air guidance means to have
essentially triangular base surfaces, the corners being rounded. In
this way, the channel offset can be easily implemented. The
rounding of the corners is advantageous for uniform flow
behavior.
[0015] It can also be useful for the air guidance means to be made
as blades. These blades can likewise provide offset channels so
that, in this way, the combustion quality is benefited.
[0016] In another preferred embodiment of this invention, it is
provided that the means for holding the glow plug are made as a
hole which runs obliquely to the cylinder axis. The glow plug must
then be simply inserted into the hole for suitable positioning. A
stop on the glow plug and/or within the hole provides for the glow
plug to be guided into its optimum position with respect to the
nozzle.
[0017] The nozzle in accordance with the invention is developed
especially advantageously in that an at least essentially
cylindrical part of the nozzle has an essentially cylindrical
shoulder with an increased diameter and that the means for holding
the glow plug are made as a hole which penetrates the shoulder
which runs obliquely to the cylinder axis. In this way, the glow
plug can be held in an area in which it influences the flow
behavior of the inflowing fuel/air mixture as little as possible.
This can be easily managed by the cylindrical stop which has a
greater diameter than the remaining nozzle body.
[0018] Likewise, it is especially advantageously provided that an
at least essentially cylindrical part of the nozzle has an
essentially cylindrical shoulder with an increased diameter and
that the cylindrical shoulder has recesses for holding the mounting
pins. These mounting pins can be securely attached, for example, to
the heat shield of the burner. The relative positioning of the
nozzle is fixed in this way by recesses in the shoulder and the
position of the mounting pins. Thus, installation is especially
simple and is possible with only low tolerances.
[0019] In an especially advantageous manner, it can be provided
that the nozzle is a Venturi nozzle. The Venturi effect for
atomization of the fuel emerging from the fuel needle can be
advantageously combined in this way with the swirl delivered to the
combustion air. The effects support one another and thus lead to
high-quality combustion.
[0020] The invention is based on the finding that a nozzle which
can be economically produced provided with a shape which can be
varied within wide limits using a ceramic material. The shaping of
the nozzle can be completed such that the air guidance means which
imparts a swirl to the entering combustion air can be made
integrally with the nozzle. Furthermore, the ceramic has the
advantage that an undesirably high temperature can be avoided in
the area of the fuel needle.
[0021] Another object consists in devising a heater for mobile
applications which can be economically produced.
[0022] This object is achieved by a heater for mobile applications,
especially motor vehicles which is provided with a burner for
combustion of a fuel/air mixture having a nozzle in accordance with
the present invention.
[0023] The invention is explained in greater detail below with
reference to the accompanying drawings which shows a preferred
embodiment of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is a partially cutaway schematic of a heater in which
the nozzle of the present invention can be used;
[0025] FIG. 2 cross-sectional side view of one embodiment of a
nozzle in accordance with the invention;
[0026] FIG. 3 is a plan view of the air entry area of a nozzle in
accordance with the invention; and
[0027] FIG. 4 shows a nozzle in accordance with the invention
mounted on a burner.
DETAILED DESCRIPTION OF THE INVENTION
[0028] In the following description of the drawings, the same
reference numbers identify the same or comparable components
throughout the various figures.
[0029] FIG. 1 shows a heater 10 for use with the nozzle of the
invention which has a burner 12 for combustion of a fuel/air
mixture. The heater comprises an annular channel fan 14 with a fan
motor 36. Combustion air 42 is taken in through the annular channel
fan 14 via an air entry connection 16 and is blown into a
combustion air collecting space 18 on the pressure side. The
combustion air which is available in the combustion air collecting
space 18 is divided into primary air and secondary air. The primary
air is conveyed into the combustion chamber 24 by a nozzle 20 which
is made as a Venturi nozzle in this example. The secondary air is
conveyed through secondary air holes 22 into the combustion chamber
24. The division of the combustion air into primary air and
secondary air is useful in order to provide a rich, ignitable
mixture at the outlet of the nozzle 20.
[0030] The nozzle 20 comprises a settling zone 26 and a diffusor 30
in order to produce the Venturi effect. Within the nozzle 20, there
is a fuel needle 28. The fuel needle 28 is supplied with fuel 44
via a fuel line 82. Due to the high flow velocity of the combustion
air in the settling zone 26, the fuel which is emerging almost
unpressurized from the fuel needle 28 is pulled into filaments
which then break down into droplets. The high air speeds which are
necessary for good atomization can be achieved by good pressure
recovery of the diffusor 30.
[0031] Furthermore, over the course of the diffusor 30, the flow
velocity of the fuel/air mixture is drastically reduced, by which
low flow velocities are accomplished in the area of the glow plug
62 which is indicated in FIG. 2. This supports the formation and
propagation of a pilot flame. After the starting process, i.e.,
ignition of the system by the glow plug 62, the glow plug is turned
off. It is used subsequently with the aid of resistance measurement
for flame monitoring.
[0032] Within the fuel chamber 24, there is a baffle disk 32. The
latter constitutes a flow barrier so that the air emerging from the
nozzle 20 is forced to the outside. In this way, good mixing of the
primary air with the secondary air takes place; this is useful with
respect to good final combustion. The area between the nozzle 20
and baffle disk 32 is thus used as a mixing zone 34 and the area on
the other side of the baffle disk 32, i.e., the area which is
downstream with respect to the baffle disk 32, is used as a
reaction zone 38. The mixture produced burns in the further course
of the combustion pipe 40 and is routed out of the heater 10 by the
parts which carry the exhaust gas. The heat generated heats the
entering cold water 46 in heat exchange with the exhaust
gas-carrying parts so that hot water 48 emerges from the heater 10.
For example, air can also be used as a heat transfer medium instead
of water.
[0033] FIG. 2 shows a partially cutaway side view of one embodiment
of a nozzle 20. This nozzle 20 can be used, for example, in a
heater 10, as is shown in FIG. 1. The nozzle 20 is made of a
ceramic material; this simplifies the production of the nozzle 20
as compared to metal nozzles. The nozzle 20 has an air entry area
50 and an air exit area 52. The air entry area 50 is connected to
the air exit area 52 via the flow path 54. This flow path 54 is
divided in this example into a settling zone 26 and a diffuser
30.
[0034] In the air entry area, there is air guidance means formed of
air guidance elements 56. These air guidance elements 56 are made
integrally with the ceramic nozzle 20. The air guidance elements 56
are aligned such that a swirl is imparted to the supplied air; this
is explained below with reference to FIG. 3. In the settling area
26, there can be a fuel needle 28 (see, FIG. 4) so that a mixture
of fuel and air emerges from the nozzle 20. This mixture can be
ignited via a glow plug 62 which can be inserted into a hole 58 of
the nozzle 20. The positioning of the glow plug 62 is thus fixed
with respect to the nozzle 20, since the glow plug 62 is held by a
hole 58 of the nozzle 20, i.e., especially not by any other parts.
Thus, very low tolerances can be maintained with respect to the
installation position of the glow plug 62. The hole 58,
advantageously, penetrates a cylindrical shoulder 64 of the nozzle
20, which shoulder has an enlarged radius; this has the advantage
that the flow behavior of the nozzle 20 is influenced only slightly
by the hole 58 or by the glow plug 62 which is located in the hole
58.
[0035] FIG. 3 shows an overhead view of the air entry area 50 of a
nozzle. One possible configuration of the air entry area 50 by air
guidance elements 56 is shown. The air guidance elements 56 form
channels 60 for the inflowing air. These channels 60 are positioned
with respect to the radii of the structure which is located
essentially on an axis such that there is an offset. Air flowing in
from the outside thus undergoes a swirl; this entails advantageous
properties with respect to atomization of the fuel which is
emerging from the fuel needle which can be located in the settling
area 26. Furthermore, in this representation, the arrangement of
the opening 58 for holding the glow plug can be recognized. The
opening 58 penetrates the essentially cylindrical shoulder 64.
Furthermore, the shoulder 64 is provided with recesses 66. These
recesses 66 define the installation position of the nozzle 20; this
is explained below with respect to FIG. 4.
[0036] FIG. 4 shows a partially cutaway view of a device in
accordance with the invention. One end of the burner 12 facing the
nozzle 20 is shown.
[0037] The burner 12 is bordered by a heat shield 78. On this heat
shield 78, there are two mounting pins 68 in this sample
embodiment. These mounting pins 68 can be welded to the heat shield
78 or to the burner 12. The mounting pins 68 define the positioning
of the other components which are described below. First of all,
there is a seal 76 which preferably is formed of a mica layer and a
graphite layer, the mica layer facing the burner 12 and the
graphite layer facing the nozzle 20. The ceramic nozzle 20 follows
and is positionally fixed on the mounting pins 68 with its recesses
66 (FIG. 3). A fuel feed 70 is connected to the fuel needle 28 and
is seated on the nozzle 20. This fuel feed 70 is positioned,
likewise, by mounting pins 68 by means of holes 84 which are
provided in a side flange. The fuel feed 70 is supplied with fuel
by a fuel line 82 in which there is a fuel sensor 80. The fuel feed
70 is followed by a spring 72 which is also seated on the mounting
pins 68. The spring 72 is held by clamping disks 74 which sit
immovably on the mounting pins 68. The spring 72 is shown in the
tensioned state in which the legs of the spring 72 are, for
example, parallel to the interposed disk. In the relieved state of
the spring 72, the legs of the spring 72 are bent up in the
direction to the interposed disk. The glow plug, which is not shown
in FIG. 4, is positioned in agreement with the embodiment of nozzle
20 shown in FIG. 2 by this nozzle and is held by a wire spring (not
shown) which is supported on the nozzle 20.
[0038] The fuel feed 70, and thus, the fuel needle 28 are
automatically aligned in this way with respect to the nozzle 20.
Therefore, only two components are involved which influence the
fuel feed and mixing of the fuel with the combustion air, so that
very small tolerances can be maintained; this is possible by axial
mounting on the same mounting pins 68. Likewise, the glow plug 62
can be positioned exactly with respect to the nozzle 20 and the
burner 12. The production of the structure shown in FIG. 4 can be
completely automated. In particular, the mounting direction is
uniformly axial so that only "threading" of the components 76, 20,
70, 72 and 74 need be performed. The seal 76 makes available heat
insulation, coupling of the nozzle ceramic 20 to the metal of the
heat shield 78, and tolerance compensation. The structure can be
advantageously mounted by power-controlled pressing of the clamping
disks 74 onto the mounting pins 68 so that, with respect to the
heat and temperature properties of the structure, uniform
prerequisites can be created. Imparted by the spring force of the
spring 72, tolerances due to the varied heating of the components,
different final temperatures of the components and different
coefficients of temperature expansion can be compensated.
[0039] The features of the invention disclosed in the description
above, in the drawings and in the claims can be important to the
implementation of the invention both individually and also in any
combination.
* * * * *