U.S. patent application number 15/314247 was filed with the patent office on 2017-04-20 for device for providing a liquid additive.
This patent application is currently assigned to CONTINENTAL AUTOMOTIVE GMBH. The applicant listed for this patent is CONTINENTAL AUTOMOTIVE GMBH. Invention is credited to Peter Bauer, Jan Hodgson.
Application Number | 20170107881 15/314247 |
Document ID | / |
Family ID | 53398060 |
Filed Date | 2017-04-20 |
United States Patent
Application |
20170107881 |
Kind Code |
A1 |
Bauer; Peter ; et
al. |
April 20, 2017 |
DEVICE FOR PROVIDING A LIQUID ADDITIVE
Abstract
The invention relates to a device for providing a liquid
additive, comprising at least one PTC heating element, which is
designed to melt frozen liquid additive in the device; wherein the
at least one PTC heating element of the device is held on both
sides by a two-part heat-conducting structure, wherein a voltage
source is connected to the two-part heat-conducting structure in
such a way that electric current can be conducted from the one
heat-conducting structure to a side of the PTC heating element and
through the PTC heating element to the other heat-conducting
structure on the other side of the PTC heating element.
Inventors: |
Bauer; Peter; (Immenreuth,
DE) ; Hodgson; Jan; (Troisdorf, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CONTINENTAL AUTOMOTIVE GMBH |
Hannover |
|
DE |
|
|
Assignee: |
CONTINENTAL AUTOMOTIVE GMBH
Hannover
DE
|
Family ID: |
53398060 |
Appl. No.: |
15/314247 |
Filed: |
June 2, 2015 |
PCT Filed: |
June 2, 2015 |
PCT NO: |
PCT/EP2015/062290 |
371 Date: |
November 28, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01N 2900/1811 20130101;
F01N 3/208 20130101; F01N 2610/10 20130101; Y02A 50/20 20180101;
F01N 3/206 20130101; F01N 2610/02 20130101; F01N 2550/05 20130101;
F01N 2610/105 20130101; F01N 3/2066 20130101; F01N 2610/1406
20130101; Y02T 10/12 20130101 |
International
Class: |
F01N 3/20 20060101
F01N003/20 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 4, 2014 |
DE |
10 2014 107 863.2 |
Claims
1. A device for providing a liquid additive, comprising: at least
one PTC heating element which is designed to melt frozen liquid
additive in the device; a two-part heat-conducting structure having
a first part and a second part, the at least one PTC heating
element being surrounded on at least two sides by the two-part
heat-conducting structure; and a voltage source connected to the
two-part heat-conducting structure; wherein electrical current is
conducted through the at least one PTC heating element from the
first part of the heat-conducting structure on one side of the PTC
heating element to the second part of the heat-conducting structure
on the other side of the PTC heating element.
2. The device of claim 1, wherein the voltage source is connected
to the two-part heat-conducting structure using electrical
conductors.
3. The device of claim 1, further comprising spacer elements
arranged between the first part and the second part of the two-part
heat-conducting structure, such that the first part and the second
part of the two-part heat-conducting structure are electrically
insulated with respect to one another.
4. The device of claim 3, further comprising a thermally conductive
bridge, wherein the spacer elements form the thermally conductive
bridge between the first part and the second part of the two-part
heat-conducting structure.
5. The device of claim 1, further comprising: a tank; a housing
which is inserted in the tank such that the housing is separate
from liquid additive, and the at least one PTC heating element and
the two-part heat-conducting structure are located in the
housing.
6. The device of claim 5, wherein the heat-conducting structure is
positioned adjacent the housing.
7. The device of claim 5, further comprising: a duct; an intake
point; a metering line; and a pump arranged in the housing, such
that the pump is connected to the intake point and a line connector
using the duct; wherein liquid additive is extracted from the tank
at the intake point, and transferred to the metering line using the
line connector.
8. The device of claim 1, further comprising: an internal
combustion engine; and, an exhaust-gas treatment device for the
purification of the exhaust gases of the internal combustion
engine; wherein the device provides liquid additive for the
exhaust-gas treatment device.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of PCT Application
PCT/EP2015/062290, filed Jun. 2, 2015, which claims priority to
German Application DE 10 2014 107 863.2, filed Jun. 4, 2014. The
disclosures of the above applications are incorporated herein by
reference.
FIELD OF THE INVENTION
[0002] The invention relates to a device for supplying a liquid
additive.
BACKGROUND OF THE INVENTION
[0003] Devices for providing a liquid additive are used for example
in the automotive field for supplying a liquid additive to an
exhaust-gas treatment device for purification of the exhaust gases
of an internal combustion engine of the motor vehicle. Exhaust-gas
treatment devices in which a liquid additive is used for the
purification of exhaust gases are widely used.
[0004] An exhaust-gas purification method particularly commonly
implemented in such exhaust-gas treatment devices is the method of
selective catalytic reduction (SCR method). In said method,
nitrogen oxide compounds in the exhaust gas are reduced with the
aid of a reducing agent. Here, ammonia is typically used as
reducing agent. The exhaust-gas treatment device typically has an
SCR catalytic converter on which the nitrogen oxide compounds in
the exhaust gas are reduced with the aid of the ammonia. Ammonia is
generally stored in motor vehicles not directly but rather in the
form of a reducing agent precursor solution. The reducing agent
precursor solution is a liquid additive. One reducing agent
precursor solution which is particularly frequently used is
urea-water solution. A 32.5% urea-water solution is available under
the trade name AdBlue.RTM..
[0005] Upon the start of operation of a device of said type, it is
a problem that said liquid additives can freeze at low
temperatures. The urea-water solution described above, for example,
freezes at -11.degree. C. Such low temperatures may be encountered
in particular during a long standstill period of the motor vehicle.
After a long standstill period, it may be the case that the liquid
additive in the device has frozen completely. The device then
initially cannot provide any liquid additive. It is known for
devices for providing liquid additive to have a heating system for
melting frozen liquid additive, such that a provision of liquid
additive is possible promptly after a start of operation.
[0006] As heating means for such devices, PTC (positive temperature
coefficient) heating elements are proposed in particular. PTC
heating elements are electrical heating elements which are heated
by an electrical current flowing through them. They have the
additional characteristic that the electrical resistance for the
current increases with rising temperature. It is thus achieved that
the electrical current automatically decreases at high
temperatures. As a result of the decrease of the electrical
current, the heating power also decreases. This provides automatic
protection of a PTC heating element against overheating.
[0007] In the case of said devices with PTC heating elements,
inadequate dissipation of the heat from the PTC heating element is
a problem, because the PTC heating element is heated up to a high
temperature in a short time, and thereafter conducts only a low
electrical current. Thus, in a short time, the heating power is
limited in self-regulating fashion, such that the desired heating
function is realized only to a small extent.
SUMMARY OF THE INVENTION
[0008] It is therefore an object of the present invention to solve
or at least alleviate the technical problems highlighted in
connection with the prior art. It is sought in particular to
propose a particularly advantageous device having at least one PTC
heating element.
[0009] These objects are achieved by means of a device according to
the features of claim 1. Further advantageous refinements of the
invention are specified in the dependent patent claims. The
features specified individually in the patent claims may be
combined with one another in any desired technologically meaningful
way and may be supplemented by explanatory facts from the
description, with further design variants of the invention being
highlighted.
[0010] A device for providing a liquid additive is proposed, which
device has at least one PTC heating element which is designed to
melt frozen liquid additive in the device, wherein the at least one
PTC heating element of the device is received, on both sides, by a
two-part heat-conducting structure, wherein a voltage source is
connected to the two-part heat-conducting structure such that
electrical current can be conducted through the PTC heating element
from one heat-conducting structure on one side of the PTC heating
element to the heat-conducting structure on the other side of the
PTC heating element.
[0011] The device is preferably inserted as an installation unit
into a tank. The device preferably has a housing, and is arranged
on the tank base of the tank. The device has, in particular, an
intake point at which liquid additive (in particular urea-water
solution) be extracted from the tank. Furthermore, the device
preferably has a line connector to which a metering line for
providing the liquid additive can be connected. Normally, a duct
runs through the device from the intake point to the line
connector. In the duct there is arranged a pump by means of which
the liquid additive can be delivered. The device has multiple PTC
heating elements. The PTC heating elements are connected by way of
a heat-conducting structure to the housing of the tank. A starting
volume of liquid additive is situated in the tank around the
device. The PTC heating elements are designed to heat liquid
additive in the starting volume through the housing of the device.
For this purpose, the heat-conducting structure bears against the
housing preferably over a large area, in order that the liquid in
the tank can be heated by way of the at least one PTC heating
element in an effective manner. The PTC heating elements (and
normally also the pump of the device) are supplied with electrical
current and an electrical voltage by a voltage source of the device
via electrical conductors. Around the outside of the housing there
is optionally also arranged a filter which delimits the starting
volume between filter and housing and covers the intake point such
that the liquid additive, as it is extracted from the tank, is
filtered by means of the filter. Around the outside of the housing,
and outside the filter, there is optionally arranged a further
coarse filter, which may prevent damage to the filter. The liquid
additive within the tank (outside the coarse filter) has a
temperature. The temperature is an operating parameter of the
device that may be taken into consideration in the execution of the
method.
[0012] Of particular importance for the described device is the
connection of the at least one PTC heating element of the device to
a heat-conducting structure of the device.
[0013] The at least one PTC heating element of the device is
received, on both sides, by a two-part heat-conducting structure,
such that the heat from the PTC heating element is conducted to the
housing and to the liquid additive in as effective a manner as
possible.
[0014] A voltage source is preferably connected to the two-part
heat-conducting structure via electrical conductors, such that the
electrical current may be conducted through the PTC heating element
from one heat-conducting structure on one side of the PTC heating
element to the heat-conducting structure on the other side of the
PTC heating element. The (two-part) heat-conducting structure thus
forms, at least in sections, electrical conductors for the
contacting of the at least one PTC heating element. By way of this
arrangement of the electrical conductors, effective utilization of
the PTC material of the PTC heating element is made possible, and
at the same time, an effective dissipation of heat from the at
least one PTC heating element is realized.
[0015] It is preferable if, furthermore, spacer elements are
arranged between the two parts of the two-part heat-conducting
structure, such that, firstly, the individual parts of the two-part
heat-conducting structure, or the two heat-conducting structures,
are electrically insulated with respect to one another, but
secondly, a thermally conductive bridge exists between the two
parts of the two-part heat-conducting structure or the two
heat-conducting structures. The spacer elements thus ensure that
the heat from the heat-conducting structure arranged on that side
of the PTC heating element which is averted from the housing can
also be dissipated to the housing.
[0016] The heat-conducting structure is preferably composed of
metal, and very particularly preferably composed of aluminum,
because aluminum exhibits high thermal conductivity and, at the
same time, a low weight.
[0017] The device is advantageous if the spacer elements form a
thermally conductive bridge between the two parts of the two-part
heat-conducting structure.
[0018] In this way, a dissipation of heat from the at least one PTC
heating element to both parts of the two-part heat-conducting
structure is possible, wherein an exchange of heat can take place
between the two parts of the heat-conducting structure. The
exchange of heat permits an equalization of heat if the heat flows
out of the two parts of the heat-conducting structure differ.
[0019] It is furthermore advantageous if the device has a housing
which is inserted in a tank for the liquid additive, wherein the
housing is free from liquid additive and the at least one PTC
heating element and the two-part heat-conducting structure are
situated in the housing. The housing is preferably insulated in
liquid-tight fashion with respect to the tank.
[0020] The device is furthermore advantageous if the
heat-conducting structure bears areally against the housing. A
(first) part of the heat-conducting structure is preferably of
areal form and bears against an inner surface of the wall of the
housing of the device. The housing of the device is preferably of
cylindrical form. The inner surface thus preferably forms an inner
circumferential surface.
[0021] A (second) part of the heat-conducting structure is
preferably likewise of areal form and bears against an upper wall
of the housing of the device. The second part of the
heat-conducting structure preferably has arm-like sections which,
at least in sections, are formed parallel to the first part of the
heat-conducting structure. PTC heating elements are arranged
between the arm-like sections of the second part of the
heat-conducting structure and the first part of the heat-conducting
structure.
[0022] A release of heat to the housing is in this case possible
both via the first part of the heat-conducting structure and via
the second part of the heat-conducting structure. Depending on the
fill level of the liquid additive in the tank, the upper wall of
the housing is or is not wetted with liquid additive. A significant
flow-off of heat via the second part of the heat-conducting
structure is to be expected only when the upper wall is wetted with
liquid additive. In order that the heat is always correctly
distributed between the first part of the heat-conducting structure
and the second part of the heat-conducting structure,
heat-conductive connections are arranged between the first part of
the heat-conducting structure and the second part of the
heat-conducting structure. The heat-conductive connections may for
example be spacer elements which are arranged adjacent to the PTC
heating elements.
[0023] The device is furthermore advantageous if a pump is arranged
in the housing, which pump is connected via a duct to an intake
point and to a line connector, wherein liquid additive may be
extracted from the tank at the intake point, and a metering line
for providing the liquid additive may be connected to the line
connector.
[0024] The housing is referred to as a "dry" housing, despite the
fact that a pump is arranged therein, because, in the housing
itself, the liquid additive does not circulate freely, and the
housing is therefore dry. Within the housing, the liquid additive
is conducted in the duct and in the pump.
[0025] Also proposed is a motor vehicle which has an internal
combustion engine, an exhaust-gas treatment device for purification
of the exhaust gases of the internal combustion engine, and a
device according to the invention for providing a liquid additive
for the exhaust-gas treatment device.
[0026] In the exhaust-gas treatment device there is preferably
arranged an SCR catalytic converter by means of which the method of
selective catalytic reduction can be carried out. The described
device is preferably connected to a metering line. The metering
line leads to a metering device by means of which the liquid
additive may be supplied to the exhaust-gas treatment device. The
metering device preferably has, for this purpose, a nozzle which
finely atomizes the liquid additive in the exhaust-gas treatment
device (if appropriate with the aid of a pressurized medium such as
air) and/or an injector by means of which the liquid additive can
be dosed. The injector may for example be a valve which is opened
and closed electrically.
[0027] The invention and the technical field will be explained in
more detail below on the basis of the figures. The figures show
particularly preferred exemplary embodiments, to which the
invention is however not restricted. In particular, it should be
noted that the figures and in particular the illustrated
proportions are merely schematic.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The present invention will become more fully understood from
the detailed description and the accompanying drawings,
wherein:
[0029] FIG. 1: shows a motor vehicle having a device;
[0030] FIG. 2: shows a tank having a device,
[0031] FIG. 3: shows a connection of a PTC heating element to a
heat-conducting structure,
[0032] FIG. 4: shows another view of the connection as per FIG.
3,
[0033] FIG. 5: shows a view into the housing of a device from
below,
[0034] FIG. 6: is a three-dimensional illustration of a two-part
heat-conducting structure, and
[0035] FIG. 7: shows a detail view of the tank from FIG. 2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0036] The following description of the preferred embodiment(s) is
merely exemplary in nature and is in no way intended to limit the
invention, its application, or uses.
[0037] FIG. 1 shows a motor vehicle 16 having an internal
combustion engine 17 and having an exhaust-gas treatment device 18
for the purification of the exhaust gases 19 of the internal
combustion engine 17. An SCR catalytic converter as exhaust-gas
purification component 21 is provided in the exhaust-gas treatment
device 18. Provided on the exhaust-gas treatment device 18 is a
metering device 20 by means of which the liquid additive 3 can be
supplied to the exhaust-gas purification component 21. Liquid
additive 3 is supplied from a tank 23 to the metering device 20 via
a metering line 22 by a device 2. The liquid additive 3 has a
temperature 34, which is in this case marked by way of example in
the tank 23. The device 2 is arranged in surroundings (e.g. in the
vicinity of the fuel tank of the motor vehicle), wherein the
surroundings have an ambient temperature 35, which is in this case
marked by way of example outside the tank 23. In the device 2 there
are arranged, inter alia, PTC heating elements (not shown here)
which are connected via electrical conductors 4 to a voltage source
5. The device 2 is connected to a monitoring unit 15.
[0038] FIG. 2 shows, in a side view, a tank 23 into which a device
2, as an installation unit 9, has been inserted. The device 2 has a
housing 26 and is arranged on the tank base 27 of the tank 23. The
device 2 has an intake point 29 at which liquid additive 3 (in
particular urea-water solution) can be extracted from the tank 23.
Furthermore, the device 2 has a line connector 28 to which a
metering line 22 for providing the liquid additive 3 can be
connected. A duct 36 runs through the device 2 from the intake
point 29 to the line connector 28. In the duct 36 there is arranged
a pump 25 by means of which the liquid additive 3 can be delivered.
The device 2 has multiple PTC heating elements 1. The PTC heating
elements 1 are connected by way of a heat-conducting structure 24
to the housing 26 of the tank 23. A starting volume of liquid
additive 3 is situated in the tank 23 around the device 2. The PTC
heating elements 1 are designed to heat liquid additive 3 in the
starting volume through the housing 26 of the device 2. The PTC
heating elements 1 (and the pump 25) are supplied with electrical
current 10 and an electrical voltage 31 by a voltage source 5 of
the device 2 via electrical conductors 4. Around the outside of the
housing 26 there is optionally also arranged a filter 30 which
delimits the starting volume between filter 30 and housing 26 and
covers the intake point 29 such that the liquid additive 3, as it
is extracted from the tank 23, is filtered by means of the filter
30. Around the outside of the housing 26, and outside the filter
30, there is optionally arranged a further coarse filter 32, which
may prevent damage to the filter 30. The liquid additive 3 within
the tank 23 (outside the coarse filter 32) has a temperature 34,
where the temperature 34 is an operating parameter 14 of the device
2 that can be taken into consideration in the execution of the
method.
[0039] FIG. 3 shows an advantageous connection of a PTC heating
element 1 to a heat-conducting structure 24. The illustration shows
a wall section of the housing 26 of the device 2 in a view from
above (cf. the side view in FIG. 2). A PTC heating element 1 is
received, on both sides, by a two-part heat-conducting structure
24, such that the heat from the PTC heating element 1 is conducted
to the housing 26 and to the liquid additive 3 in as effective a
manner as possible. A voltage source 5 is connected via electrical
conductors 4 to the two-part heat-conducting structure 24, such
that the electrical current 10 is conducted through the PTC heating
element 1 from one heat-conducting structure 24 on one side of the
PTC heating element 1 to the heat-conducting structure 24 on the
other side of the PTC heating element 1. By way of this arrangement
of the electrical conductors 4, effective utilization of the PTC
material of the PTC heating element 1 is made possible, and at the
same time, an effective dissipation of heat is realized.
Furthermore, the spacer elements 13 are arranged between the
two-part heat-conducting structure 24, such that, firstly, the
individual heat-conducting structures 24 are electrically insulated
with respect to one another, but secondly, a thermally conductive
bridge exists between the heat-conducting structures 24. The spacer
elements 13 thus ensure that the heat from the heat-conducting
structure 24 arranged on that side of the PTC heating element 1
which is averted from the housing 26 can also be dissipated to the
housing 26.
[0040] FIG. 4 shows a side view of the connection as per FIG. 3
along the section line V indicated in FIG. 3. The heat-conducting
structure 24 is arranged, in the vicinity of the housing 26, within
the device 2. The housing 26 is connected to the tank base 27.
[0041] FIG. 5 shows a view into the housing 26 of a device 2 from
below. A circumferential wall 6 of the housing 26 and an upper wall
7 of the housing 26 are correspondingly visible. A first part 8 of
the heat-conducting structure 24 bears against the circumferential
wall 6. A second part 9 of the heat-conducting structure bears
against the upper wall 6. The second part 9 of the heat-conducting
structure 24 has arms 10 which, at least in sections, run parallel
to the first part 8 of the heat-conducting structure 24. PTC
heating elements 1 are arranged between the arms 10 of the second
part 9 and the first part 8. Furthermore, spacer elements 13 are
arranged between the arms 10 of the second part 9 and the first
part 8. Likewise indicated in FIG. 5 are a pump 25 of the device
and a duct 36 via which the pump 25 draws in the liquid additive at
an intake point 29.
[0042] FIG. 6 shows a three-dimensional view of the two-part
heat-conducting structure 24 with a first part 8 and with a second
part 9.
[0043] FIG. 7 shows a detailed view of the tank 23 from FIG. 2 with
a device 1. Additionally to the disclosure of FIG. 4, it can be
seen here that the heat-conducting structure 24 is of two-part form
with a first part 8 and a second part 9.
[0044] The invention permits particularly advantageous operation of
a device for providing liquid additive. In particular, functional
testing of the heat-conducting connection of PTC heating elements 1
to heat-conducting structures 24 and/or housing 26 is possible. In
this way, it can be detected whether possible amendments or repairs
(possibly also a replacement of the device) are necessary.
[0045] The description of the invention is merely exemplary in
nature and, thus, variations that do not depart from the gist of
the invention are intended to be within the scope of the invention.
Such variations are not to be regarded as a departure from the
spirit and scope of the invention.
* * * * *