U.S. patent application number 14/006125 was filed with the patent office on 2014-03-06 for exhaust gas after treatment system.
This patent application is currently assigned to ALBONAIR GMBH. The applicant listed for this patent is Sacha Dolenec, Sebastian Muhlenbrock, Werner Overhoff. Invention is credited to Sacha Dolenec, Sebastian Muhlenbrock, Werner Overhoff.
Application Number | 20140065022 14/006125 |
Document ID | / |
Family ID | 45562272 |
Filed Date | 2014-03-06 |
United States Patent
Application |
20140065022 |
Kind Code |
A1 |
Overhoff; Werner ; et
al. |
March 6, 2014 |
Exhaust Gas After Treatment System
Abstract
The invention relates to an exhaust gas aftertreatment system
for delivering a reducing agent (15) into the exhaust gas stream of
an internal combustion engine for selective catalytic reduction,
the system having a reducing agent tank (1) and a pump (3) for
delivering the reducing agent from the tank (1) to an injection
unit, the tank (1) having at least one opening, the pump (3) being
made as an integrated unit (2) and being plugged into the opening
of the tank, the integrated unit (2) forming a tank closure and
sealing the tank.
Inventors: |
Overhoff; Werner; (Marl,
DE) ; Dolenec; Sacha; (Holzwickede, DE) ;
Muhlenbrock; Sebastian; (Datteln, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Overhoff; Werner
Dolenec; Sacha
Muhlenbrock; Sebastian |
Marl
Holzwickede
Datteln |
|
DE
DE
DE |
|
|
Assignee: |
ALBONAIR GMBH
Dortmund
DE
|
Family ID: |
45562272 |
Appl. No.: |
14/006125 |
Filed: |
January 27, 2012 |
PCT Filed: |
January 27, 2012 |
PCT NO: |
PCT/EP2012/000374 |
371 Date: |
November 20, 2013 |
Current U.S.
Class: |
422/110 ;
422/119; 422/168; 422/173 |
Current CPC
Class: |
F01N 2610/1406 20130101;
F01N 3/208 20130101; F01N 2610/10 20130101; F01N 2610/1433
20130101; Y02T 10/24 20130101; F01N 2610/02 20130101; F01N 3/2066
20130101; Y02T 10/12 20130101; F01N 2610/144 20130101 |
Class at
Publication: |
422/110 ;
422/168; 422/173; 422/119 |
International
Class: |
F01N 3/20 20060101
F01N003/20 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 21, 2011 |
DE |
10 2011 014 634.2 |
Claims
1. An exhaust gas after treatment system for delivering a reducing
agent into the exhaust gas stream of an internal combustion engine
for selective catalytic reduction, the system comprising a reducing
agent tank, an injection unit and a pump for delivering the
reducing agent from the said reducing agent tank to said injection
unit, characterized in that said reducing agent tank has at least
one opening, the pump being made as an integrated unit and being
plugged into the opening of the tank, the integrated unit forming a
tank closure and sealing said tank, wherein the injection unit
comprises at least one nozzle by which the reducing agent is
injected into the exhaust gas stream and/or is atomized in the
exhaust gas stream, wherein compressed air is used for atomization
in order to form a uniform, finely distributed aerosol.
2. The exhaust gas after treatment system as claimed in claim 1,
wherein the integrated unit is screwed into a thread in the opening
of said tank, forming a seal or wherein the unit is inserted into
the opening of the tank by means of a quarter-turn fastener,
forming a seal.
3. The exhaust gas after treatment system as claimed in claim 1
wherein the at least one opening is located at or near the bottom
and/or in the lower region of said tank and the unit (2) seals said
tank at said at least one opening.
4. The exhaust gas after treatment system as claimed in claim 1
wherein the system at least on member selected from the group
consisting of reducing agent filters filter and/or a heating
apparatuses for heating of the reducing agent, temperature sensors
for detecting the reducing agent temperature, power electronics for
triggering the pump and/ communications interfaces, especially a
standardized communications interface, including a CAN bus
interface.
5. The exhaust gas after treatment system as claimed in claim 1
wherein the pump as an integrated unit has at least one member
selected from the group consisting of reducing agent filters
heating apparatuses for heating of the reducing agent, temperature
sensors for detecting the reducing agent temperature, power
electronics for triggering the pump and communication interfaces,
especially CAN bus interfaces.
6. The exhaust gas after treatment system as claimed in claim 1
wherein the pump as an integrated unit has a sensor for detecting a
physical property of the reducing agent, especially for detection
of the electrical conductivity and/or for detection of the speed of
sound in the reducing agent.
7. The exhaust gas after treatment system as claimed in claim 6,
wherein the sensor for detecting a physical property of the
reducing agent is arranged in the tank such that the signal of the
sensor can be used at the same time as a liquid level indicator for
ascertaining that a minimum level in the tank has not been
reached.
8. The exhaust gas after treatment system as claimed in claim 1
wherein the system has a control device by means of which the pump
is triggered depending on the measured values acquired by the
sensors and/or depending on the current operating parameters of the
internal combustion engine, in particular is triggered via a bus
system.
9. The exhaust gas after treatment system as claimed in claim 1
wherein there is at least one seal, especially an O-ring seal
between the unit and the tank.
10. The exhaust gas after treatment system as claimed in claim 1
wherein the system has an injection unit with at least one nozzle
by which the reducing agent is injected into the exhaust gas stream
and/or is atomized in the exhaust gas stream.
11. The exhaust gas after treatment system as claimed in claim 2
wherein the system has an SCR catalytic converter in which the
reducing agent is delivered into the exhaust gas stream of the
internal combustion engine for selective catalytic reduction,
upstream and/or downstream of the SCR catalytic converter there
being a sensor for detecting the nitrogen oxide concentration in
the exhaust gas.
12. The exhaust gas after treatment system as claimed in claim 2
wherein the integrated unit is screwed into a thread in the opening
of the reducing agent tank forming a seal or wherein the integrated
unit is inserted into the opening of the reducing agent tank by
means of a quarter-turn fastener, forming a seal.
13. The exhaust gas after treatment system as claimed in claim 2
wherein the at least one opening is located on the bottom and/or in
the lower region of the reducing agent tank and the integrated unit
seals the reducing agent tank at said at least one opening.
14. The exhaust gas after treatment system as claimed in claim 2
wherein the system has at least one member selected from the group
consisting of reducing agent filters, heating apparatuses for
heating of the reducing agent, temperature sensors for detecting
the reducing agent temperature, power electronics for triggering
the pump and communications interfaces, especially a standardized
communications interface, particularly a CAN bus interface.
15. The exhaust gas after treatment system as claimed in claim 2
wherein the pump as an integrated unit has at least one member
selected from the group consisting of reducing agent filters,
heating apparatuses for heating of the reducing agent, temperature
sensors for detecting the reducing agent temperature, power
electronics for triggering the pump and interfaces, especially a
CAN bus interface.
16. The exhaust gas after treatment system as claimed in claim 2
wherein the pump is an integrated unit having a sensor for
detecting a physical property of the reducing agent, especially for
detection of the electrical conductivity and/or for detection of
the speed of sound in the reducing agent.
17. The exhaust gas after treatment system as claimed in claim 16,
wherein the sensor for detecting a physical property of the
reducing agent is arranged in the reducing agent tank such that the
signal of the sensor can be used at the same time as a liquid level
indicator for ascertaining that a minimum level in the reducing
agent tank has not been reached.
18. The exhaust gas after treatment system as claimed in claim 2
wherein the system has a control device by means of which the pump
is triggered depending on the measured values acquired by the
sensors and/or depending on the current operating parameters of the
internal combustion engine, in particular is triggered via a bus
system.
19. The exhaust gas after treatment system as claimed in claim 2
wherein there is at least one seal, especially an O-ring seal
between the integrated unit and the reducing agent tank.
20. The exhaust gas after treatment system as claimed in claim 2
wherein the system has an injection unit with at least one nozzle
by which the reducing agent is injected into the exhaust gas stream
and/or is atomized in the exhaust gas stream and further comprising
an SCR catalytic converter in which the reducing agent is delivered
into the exhaust gas stream of the internal combustion engine for
selective catalytic reduction, upstream and/or downstream of the
SCR catalytic converter there being a sensor for detecting the
nitrogen oxide concentration in the exhaust gas.
Description
[0001] The invention relates to an exhaust gas aftertreatment
system for delivering a reducing agent into the exhaust gas stream
of an internal combustion engine for selective catalytic reduction,
the system having a reducing agent tank and a pump for delivering
the reducing agent from the tank to an injection unit.
[0002] These exhaust gas aftertreatment systems are known and are
used to reduce nitrogen oxides in exhaust gases from internal
combustion engines, injection of a reducing agent, such as a urea
solution, especially according to DIN 70070, into the exhaust gas
stream of the internal combustion engine taking place. Exhaust gas
aftertreatment systems with delivery of a reducing agent into the
exhaust gas stream for selective catalytic reduction of nitrogen
oxides (SCR) are used to minimize nitrogen oxide emissions from
internal combustion engines. To do this, a reducing agent is
injected into the exhaust gas system with a metering and injection
device. Ammonia is the reducing agent. In this sense a reducing
agent or urea solution is to be understood as ammonia and also urea
solution or another reductively acting agent and especially
so-called AdBlue, i.e. a urea solution according to DIN 70070.
[0003] In these exhaust gas systems a reducing agent such as for
example urea solution is injected by means of compressed air into
the exhaust gas stream and atomized in order to form an aerosol
which is as fine and uniformly distributed as possible. The
reducing agent is used for selective catalytic reduction (SCR) in
so-called SCR catalytic converters for reduction of nitrogen oxide
emissions from diesel engines.
[0004] The disadvantage in known exhaust gas aftertreatment systems
is their complex structure of a plurality of units and modules;
this entails very high production and installation effort and
requires a large installation space; this is especially
disadvantageous in applications in the domain of passenger cars
since the available installation space is very limited.
[0005] Proceeding from this prior art, the object of the invention
is to reduce the installation effort of the components which are to
be installed in the exhaust gas aftertreatment system and thus to
cut production costs. Another object is that in the production of
the exhaust gas aftertreatment system fewer parts need be installed
and the installation space is optimized.
[0006] This object is achieved as claimed in the invention by an
exhaust gas aftertreatment system as claimed in Claim 1.
Advantageous developments of the invention are given in the
dependent claims.
[0007] In the exhaust gas aftertreatment system for delivering a
reducing agent into the exhaust gas stream of an internal
combustion engine for selective catalytic reduction, the system
having a reducing agent tank and a pump for delivering the reducing
agent from the tank to an injection unit, it is especially
advantageous for the tank to have at least one opening, the pump
being made as an integrated unit and being plugged into the opening
of the tank, the unit forming a tank closure and sealing the
tank.
[0008] The reducing agent which is to be delivered is preferably a
urea solution especially according to DIN 70070 for selective
catalytic reduction. The term reducing agent encompasses however
any suitable liquid substance. But preferably a urea solution is
used. The tank is accordingly made diffusion-tight and consists
preferably of plastic.
[0009] The pump for delivery of the reducing agent from the tank to
the injection unit thus forms an integrated unit which is plugged
into the tank so that the tank more or less forms the pump housing.
The pump unit thus closes the tank and seals it.
[0010] The opening of the tank into which the pump as an integrated
unit is plugged is preferably located on the bottom of the tank or
in a lower region of one side wall of the tank so that the intake
fitting of the pump is also covered at a low level of the reducing
agent and delivery of the reducing agent from the tank is
possible.
[0011] The pump as an integrated unit for this purpose has an
intake fitting whose intake opening is located at the geodetically
lowest point of the tank.
[0012] Alternatively the pump unit can be plugged into an opening
on the top of the tank or in the upper region of one side wall of
the tank and can seal the tank. In this case the pump also has a
suction fitting which, optionally provided with an extension,
discharges at the geodetically lowest point of the tank so that the
intake fitting of the pump or the open end of the pipeline or hose
line connected upstream of the suction fitting is covered even at a
low level of the reducing agent and delivery of the reducing agent
from the tank is possible.
[0013] It is advantageous here that the tank cannot become leaky
toward the bottom if for example a seal between the pump unit and
the tank opening has not been correctly installed.
[0014] If the configuration of the tank due to the given
installation situation requires, the tank can have any shape which
differs from a roughly cuboidal shape, as is conventional in tanks
installed in motor vehicles. In this case the pump unit can also be
inserted into the tank in a diagonal position which differs from a
vertical or horizontal position and can seal it. Fundamentally the
location of the pump unit in the installed position and its
arrangement in the tank, i.e. also the arrangement of the tank
opening into which the pump unit is plugged, are optional.
Therefore the pump unit in its installation situation can be
located vertically, horizontally or diagonally.
[0015] The tank and pump as an integrated unit thus form a compact
unit which can be installed premounted into the vehicle. The
required installation space within the motor vehicle is minimized
and optimally used by the tank and pump forming a compact unit.
[0016] Since the tank can preferably be a plastic tank, it can be
optimally adapted in its geometry to the existing installation
space. The tank is preferably a diffusion-tight plastic tank.
[0017] The pump as an integrated unit is inserted like a cartridge
into the opening of the tank intended for installation of the pump.
Preferably the pump unit is screwed into a thread in the opening of
the tank, forming a seal. Alternatively or cumulatively the pump
unit can be inserted into the tank opening by means of a
quarter-turn fastener, forming a seal.
[0018] The unit is preferably made such that one bottom plate bears
the pump and other components so that the bottom plate forms a
somewhat smooth-surfaced tank closure and the components of the
pump unit in the installed state lie within the tank. The tank then
more or less forms the pump housing.
[0019] Preferably the opening is located on the bottom of the tank
or in the lower region of one side wall of the tank and the pump
unit or bottom plate of the unit seals the tank downward.
[0020] Alternatively or cumulatively the border of the tank opening
can be made stepped so that a bottom plate of the pump unit is
inserted into one step and is braced against the tank and seals it
by means of clamps which are located on the tank and which reach
behind corresponding undercuts on the bottom plate.
[0021] On the top of the tank there is preferably a refill fitting
for delivering the required reducing agent solution into the
reducing agent tank. The terms reducing agent or reducing agent
solution are used synonymously in this sense and encompass any
suitable reducing agent for selective catalytic reduction.
[0022] The pump as an integrated unit can be inserted into the tank
and mounted from the bottom, like an oil filter or like a cartridge
which is inserted and attached.
[0023] In one especially preferred configuration of the exhaust gas
aftertreatment system the system has a reducing agent filter and/or
a heating apparatus for heating of the reducing agent and/or a
temperature sensor for detecting the reducing agent temperature
and/or pure power electronics for triggering the pump and/or a
communications interface, especially a standardized communications
interface, especially a CAN bus interface and/or a LIN bus
interface.
[0024] Especially preferably the pump as an integrated unit has a
reducing agent filter and/or a heating apparatus for heating of the
reducing agent and/or a temperature sensor for detecting the
reducing agent temperature and/or power electronics for triggering
the pump and/or a communications interface, especially a
standardized communications interface, especially a CAN bus
interface and/or a LIN bus interface.
[0025] Integrating other components into the integrated unit with
the pump yields an especially compact embodiment which can be
advantageously installed. Insertion of this integrated unit with
pump and other components into the tank yields a compact unit which
can be installed completely premounted into the vehicle, especially
a passenger car, and to which then only the delivery line for
delivery of the reducing agent to the injection unit is connected.
This reducing agent line is preferably heated. Likewise there is
preferably a heating apparatus for heating of the reducing agent.
The reducing agent solution according to DIN 70070 freezes at
-11.degree. C. so that for especially low outside temperatures at
least in the region of the intake fitting of the pump there is a
heating apparatus in order to enable delivery of the reducing agent
from the tank by means of the pump even at low outside temperatures
in order to thaw the reducing agent in the tank if it should be
frozen.
[0026] The arrangement of an interface, especially a standardized
communications interface, such as for example a CAN bus interface
and/or a LIN bus interface makes it possible to incorporate the
pump unit into the control system of the vehicle. This so-called
CAN bus is an asynchronous serial bus system. A so-called LIN bus
is a serial communications system.
[0027] In one preferred embodiment the pump as an integrated unit
has a sensor for detecting a physical property of the reducing
agent, especially for detection of the electrical conductivity
and/or for detection of the speed of sound in the reducing
agent.
[0028] By means of this sensor permanent detection and monitoring
of the quality of the reducing agent are possible so that any
manipulations, for example of filling of the tank with water, can
be effectively prevented in order to ensure proper operation of the
exhaust gas aftertreatment system. Thus, by this reducing agent
quality sensor by means of which a physical property of the
delivered reducing agent is detected it can be ascertained whether
the correct reducing agent is being used and injected into the
exhaust gas line for exhaust gas aftertreatment.
[0029] As the physical quantity for detecting the reducing agent
quality the electrical conductivity of the reducing agent and/or
the speed of sound in the reducing agent can be measured by means
of the sensor and transferred to an evaluation unit.
[0030] In one especially preferred embodiment the sensor for
detecting a physical property of the reducing agent is arranged in
the tank such that the signal of the sensor can be used at the same
time as a liquid level indicator for ascertaining that a minimum
level in the tank has not been reached.
[0031] The sensor for detecting a physical property of the reducing
agent is accordingly positioned in the tank such that at the same
time it is used as a liquid level indicator so that a display can
be activated when the tank reserve is reached. The sensor is thus
used at the same time as a liquid level sensor or liquid level
transmitter for reserve display.
[0032] Preferably the system has a control device by means of which
the pump is triggered depending on the measured values acquired by
the sensors and/or depending on the current operating parameters of
the internal combustion engine, in particular is triggered via a
bus system.
[0033] This control unit can also be the central control device of
the vehicle. In this case the triggering and operation monitoring
of the exhaust gas aftertreatment system can be integrated into the
central control device of the motor vehicle and implemented
accordingly.
[0034] Preferably there is at least one seal, especially an O-ring
seal, between the pump unit and the tank.
[0035] The arrangement of this seal ensures reliable sealing of the
tank.
[0036] Preferably the system has an injection unit with at least
one nozzle by which the reducing agent is injected into the exhaust
gas stream and/or is atomized in the exhaust gas stream. In
particular compressed air can be used for atomization in order to
form a uniform, finely distributed aerosol and to achieve optimum
and uniformly distributed droplet formation.
[0037] The exhaust gas aftertreatment system preferably has a SCR
catalytic converter in which the reducing agent is delivered into
the exhaust gas stream of the internal combustion engine for
selective catalytic reduction, upstream and/or downstream of the
SCR catalytic converter there being a sensor for detecting the
nitrogen oxide concentration in the exhaust gas.
[0038] These NOx sensors enable online monitoring and diagnosis of
the selective catalytic reduction in the SCR catalytic converter,
i.e. the quality of the exhaust gas aftertreatment, and at the same
time triggering of the pump to deliver the reducing agent from the
tank to the injection unit depending on the values which have been
ascertained by means of the NOx sensor or sensors is possible in
order to trigger the exhaust gas aftertreatment system as
required.
[0039] One exemplary embodiment of the invention is shown in the
figures and is explained below.
[0040] FIG. 1 shows a schematic of a tank with an inserted pump
unit.
[0041] FIG. 1 shows a schematic of a tank 1 in which the reducing
agent solution 15 is stored. The tank 1 is preferably a
diffusion-tight plastic tank.
[0042] In the lower region of the tank 1 a pump unit 2 which is
made as an integrated unit is inserted into an opening of the tank
1.
[0043] The integrated unit 2 contains the pump 3 and the power
electronics 4 for triggering the pump and other components which
are explained below.
[0044] In the unit 2 there is furthermore a temperature sensor 5
such as for example an NTC temperature sensor for detecting the
temperature of the reducing agent solution 15 in the tank 1. The
temperature sensor 5 is used at the same time for heating control
and for density compensation of the reducing agent via the
temperature. The heating element can be a resistance element. In
the illustrated exemplary embodiment the heating element 6 is a
MOSFET transistor which is likewise triggered via the power
electronics 4 of the integrated unit 2.
[0045] The integrated unit 2 has corresponding terminals for the
liquid level sensor 8 and furthermore a standardized communications
interface such as for example a CAN bus system, a power supply via
the vehicle electrical system with a +12 volt terminal and a
so-called ground terminal (0 volt).
[0046] The integrated module 2 is plugged into the opening of the
tank 1 located in the lower region of the tank 1 and is sealed by
means of O-ring seals 10. The suction fitting 11 is arranged such
that it lies in the lower region of the tank 1 so that a residual
amount of the reducing agent 15 located in the tank 1 can also be
intaken via the pump 3 through the suction fitting 11. A filter 7
by which the reducing agent 15 is filtered is connected upstream of
the suction fitting 11 on the pump 3.
[0047] In addition to the MOSFET transistor 6 which is used as the
heating element, a heating element 9 is placed in the tank which in
the illustrated exemplary embodiment is an aluminum rod which is
used for heating of the tank contents 15 in order to thaw them at
extremely low temperatures so that in the lower region of the tank
1 the reducing agent can be thawed in order to intake it via the
suction fitting 11 by means of the pump 3 through the filter 7.
[0048] The delivery end 12 of the pump is integrated into the
module 2; a heated reducing agent line is connected to that end and
discharges into an injection unit for injecting the reducing agent
into the exhaust gas stream of the internal combustion engine.
[0049] Furthermore in the tank 1 there is a liquid level sensor 8
which is likewise wired to the power electronics 4, as is suggested
in FIG. 1. By means of the sensor 8 the liquid level within the
tank 1 is monitored in that via the reducing agent 15 added to the
tank 1 the circuit between the liquid level sensor 8 and the
aluminum rod 9 and/or the aluminum pipe 11 is closed. As soon as
this circuit is broken, the reserve region of the tank 1 is reached
and a reserve lamp is turned on as a display for the driver.
Refilling of the tank 1 with the reducing agent 15 is possible via
the refill fitting 13 which is located on the top of the tank
1.
[0050] The entire module 2 as an integrated module is plugged into
the opening located in the lower region of the tank 1 and is sealed
by means of the O-ring seals 10. For complete installation of the
entire arrangement only the module 2 need be installed in the tank
1 and the plug-and-socket connections to the power electronics 4
which are used for triggering of the heating element and pump and
also monitoring of the liquid level sensor or liquid level
transmitter 8 need be coupled.
[0051] The suction fitting 11 of the pump 3 is located in the lower
region of the tank 1 so that even when the region of the reserve
tank is reached, i.e. when the liquid level sensor 8 is not reached
in terms of the liquid level and no longer responds, further
operation of the exhaust gas aftertreatment system for a certain
time is possible until the tank 1 is filled again with the reducing
agent 15 via the refill fitting 13.
[0052] At the same time, the electrical conductivity of the
reducing agent 15 between the lower end of the liquid level sensor
8 and the heating element 9 is monitored by a measurement of the
electrical resistance between the sensor 8 and the heating rod 9 in
order to perform quality control of the reducing agent 15 which has
been added to the tank 1. In this way it can be ascertained if for
example water instead of a reducing agent according to DIN 70070
has been added. The sensor 8 is thus used at the same time for
monitoring the quality of the added reducing agent 15 and for
monitoring of the liquid level in the tank 1.
[0053] On the pump housing inserted into the tank the liquid level
sensor 8 in one alternative embodiment is made with several contact
surfaces over the height of the tank 1 in order to implement a more
accurate and detailed liquid level display with several
intermediate steps for more exact indication of the remaining tank
contents.
[0054] In one alternative which is not shown, the integrated module
as an integrated module is plugged into an opening located in the
upper region of the tank from overhead and is sealed by means of
O-ring seals. The tank in the lower region then has a continuous,
diffusion-tight plastic trough. Possible tank leaks for faulty
installation of the O-ring seals are thus eliminated.
[0055] In this case a heating element is integrated into the module
and is thus likewise pushed from overhead into the tank so that the
additional aluminum heating rod can be omitted.
* * * * *