U.S. patent application number 14/788307 was filed with the patent office on 2016-05-12 for urea backflow prevention apparatus of scr and a control method thereof.
This patent application is currently assigned to Hyundai Motor Company. The applicant listed for this patent is Hyundai Motor Company. Invention is credited to Suk-Il PARK, Dae-Won YANG.
Application Number | 20160131002 14/788307 |
Document ID | / |
Family ID | 55911861 |
Filed Date | 2016-05-12 |
United States Patent
Application |
20160131002 |
Kind Code |
A1 |
YANG; Dae-Won ; et
al. |
May 12, 2016 |
UREA BACKFLOW PREVENTION APPARATUS OF SCR AND A CONTROL METHOD
THEREOF
Abstract
A urea backflow prevention apparatus of Selective Catalytic
Reduction (SCR) system that injects a urea aqueous solution to an
exhaust pipe may include a urea tank storing the urea aqueous
solution, a nozzle being installed on the exhaust pipe and
injecting the urea aqueous solution into the exhaust pipe, a supply
pump pressurizing the urea aqueous solution in order to inject the
urea aqueous solution from the nozzle to the exhaust pipe, a
suction line supplying the urea aqueous solution stored in the urea
tank to the supply pump by connecting the urea tank and the supply
pump, a pressure line delivering the urea aqueous solution
pressurized at the supply pump to the nozzle by connecting the
supply pump and the nozzle, and a return line collecting urea
aqueous solution not injected at the nozzle to the urea tank by
connecting the supply pump and the urea tank.
Inventors: |
YANG; Dae-Won; (Anyang-si,
KR) ; PARK; Suk-Il; (Hwaseong-si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hyundai Motor Company |
Seoul |
|
KR |
|
|
Assignee: |
Hyundai Motor Company
Seoul
KR
|
Family ID: |
55911861 |
Appl. No.: |
14/788307 |
Filed: |
June 30, 2015 |
Current U.S.
Class: |
60/274 ;
60/295 |
Current CPC
Class: |
Y02A 50/2325 20180101;
Y02T 10/24 20130101; F01N 2610/144 20130101; F01N 2610/1486
20130101; F01N 3/208 20130101; F01N 2610/02 20130101; Y02A 50/20
20180101; Y02T 10/12 20130101; F01N 2610/1473 20130101; F01N
2610/1433 20130101 |
International
Class: |
F01N 3/20 20060101
F01N003/20; F01N 3/28 20060101 F01N003/28 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 11, 2014 |
KR |
10-2014-0155997 |
Claims
1. A urea backflow prevention apparatus of Selective Catalytic
Reduction (SCR) system that injects a urea aqueous solution to an
exhaust pipe, the urea backflow prevention apparatus of SCR
comprising: a urea tank storing the urea aqueous solution; a nozzle
being installed on the exhaust pipe and injecting the urea aqueous
solution into the exhaust pipe; a supply pump pressurizing the urea
aqueous solution of the urea tank to inject the urea aqueous
solution from the nozzle to the exhaust pipe; a suction line
supplying the urea aqueous solution stored in the urea tank to the
supply pump by connecting the urea tank and the supply pump; a
pressure line connecting the supply pump and the nozzle and
delivering the urea aqueous solution pressurized at the supply pump
to the nozzle; and a return line collecting a urea aqueous solution
not injected at the nozzle to the urea tank by connecting the
supply pump and the urea tank.
2. The urea backflow prevention apparatus of the SCR system of
claim 1, further comprising a shut-off valve disposed on the
suction line and selectively opening the suction line.
3. The urea backflow prevention apparatus of the SCR system of
claim 2, further comprising a urea detection device being provided
in at least one of the supply pump and the pressure line, and
detecting whether the urea aqueous solution exists in the at least
one of the supply pump and the pressure line after an operation of
the SCR system is terminated.
4. The urea backflow prevention apparatus of the SCR system of
claim 3, further comprising a controller receiving a signal of
whether the urea aqueous solution exists in the at least one of the
supply pump and the pressure line from the urea detection device
and transmits a signal for the shut-off valve to selectively open
the suction line after the operation of the SCR system is
terminated.
5. The urea backflow prevention apparatus of the SCR system of
claim 1, wherein the urea tank comprises a ventilating opening
opened to atmosphere.
6. The urea backflow prevention apparatus of the SCR system of
claim 2, wherein the return line is formed to be shorter than the
suction line so that a lower part of the return line is
continuously positioned on a surface of the urea aqueous solution
inside of the urea tank.
7. A control method for a urea backflow prevention apparatus of
Selective Catalytic Reduction (SCR), comprising: an engine stop
determination step by a controller of determining whether an engine
of a vehicle is stopped; a urea collection step of collecting a
urea aqueous solution inside of a pressure line, a supply pump and
a suction line by operating the supply pump in a reverse direction,
when the engine is determined to be stopped at the engine stop
determination step; a urea collection completion determination step
of determining whether the collection of the urea aqueous solution
has been completed by the controller receiving a signal on whether
the urea aqueous solution exists in at least one of the supply pump
and the pressure line from a urea detection device, after the urea
collection step; and a shut-off valve closure step of closing a
shut-off valve by transmitting a signal from the controller to the
shut-off valve, when it is determined by the controller that the
collection of the urea aqueous solution has been completed, after
the urea collection completion determination step.
8. The control method for the urea backflow prevention apparatus of
the SCR of claim 7, further comprising an engine operation
determination step of determining whether the engine is operated
again by the controller, after the shut-off valve closure step.
9. The control method for the urea backflow prevention apparatus of
the SCR of claim 8, further comprising a shut-off valve open step
of opening the shut-off valve by transmitting a signal from the
controller to the shut-off valve, when it is determined by the
controller that the engine is operated again at the engine
operation determination step.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority to Korean Patent
Application No. 10-2014-0155997, filed Nov. 11, 2014, the entire
contents of which is incorporated herein for all purposes by this
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a urea backflow prevention
apparatus of SCR and a control method thereof, and more
particularly, to a urea backflow prevention apparatus of SCR and a
control method thereof that prevents a breakage of a supply pump
due to the freezing of urea aqueous solution flowed backward.
[0004] 2. Description of Related Art
[0005] There have been the problems of serious environmental
pollution by emissions exhausted from internal combustion engines
of vehicles using fossil fuel such as gasoline or diesel. In
particular, the discharging of soot, nitrogen oxides (NOx) and fine
dust including soot exhausted from diesel vehicles such as buses
and trucks are perceived as a serious problem, and thus, each
country controls strictly emission of exhaust gas by preparing
related regulations in order to solve exhaust gas problems of such
above diesel vehicles.
[0006] Generally, the exhaust system of a diesel engine is provided
with an exhaust gas post-processing device such as Diesel Oxidation
Catalyst (DOC), Diesel Particulate matter Filter (DPF), Selective
Catalyst Reduction (SCR) and Lean NOx Trap (LNT) and so on in order
to reduce the pollutants contained in the exhaust gas such as
carbon monoxide (CO), hydrocarbon (HC), particulate matter, and
nitrogen oxides (NOx), and so on.
[0007] Among them, an exhaust gas post-processing device
(hereinafter, referred to as "SCR system") using an SCR may
function as injecting a reducing agent such as urea inside an
exhaust pipe and thereby reducing nitrogen oxides in the exhaust
gas to nitrogen and oxygen. In other words, the above SCR system
injects a reducing agent such as urea into an exhaust pipe, and
then the reducing agent is converted to ammonia (NH3) by the heat
of exhaust gas, thereby reducing nitrogen oxides (NOx) to nitrogen
gas (N2) and water (H2O) by a catalytic reaction of nitrogen oxides
(NOx) and ammonia in the exhaust gas via the SCR catalyst.
[0008] FIG. 1A and FIG. 1B are views illustrating the SCR system
according to the related art and FIG. 2A and FIG. 2B are views
illustrating problems of the SCR system according to the related
art.
[0009] Referring to FIG. 1A, FIG. 1B, FIG. 2A and FIG. 2B, the SCR
system in accordance with the related art pressurizes the urea
aqueous solution stored in a urea tank via a pump in order to
inject it through a nozzle into the exhaust pipe during normal
operation (refer to FIG. 1A). In addition, when an engine is
stopped, the SCR system collects again the urea aqueous solution to
the urea tank (refer to FIG. 1B). The purpose of collecting the
urea aqueous solution is to prevent breakage of parts of the SCR
system due to the increasing of the urea volume by freezing when
the temperature is lowered in the winter.
[0010] However, if a vehicle mounted with the SCR system based on a
conventional technology is parked outside for a long time in the
winter after the urea aqueous solution has been all collected, the
temperature inside the SCR system will drop from a normal operation
temperature (about 40.quadrature.) to below zero as the temperature
inside the SCR system goes in equilibrium with outdoor temperature.
In this case, the pressure in an internal flow path in the closed
SCR system which was in equilibrium with the atmospheric pressure
when collecting the urea aqueous solution may be lowered (refer to
FIG. 2A) and thereby the urea aqueous solution inside a urea tank
may flow backward to a supply pump through a suction line (refer to
FIG. 2B). Therefore, a problem occurred that a supply pump was
broken if the urea aqueous solution flowed backward was frozen.
[0011] The above information disclosed in this Background section
is only for enhancement of understanding of the background of the
invention and therefore it may contain information that does not
form the prior art that is already known in this country to a
person of ordinary skill in the art.
BRIEF SUMMARY
[0012] Various aspects of the present invention are directed to
providing a urea backflow prevention apparatus of SCR and a control
method thereof which prevents a urea aqueous solution in a urea
tank inside of a stopped vehicle from being flowed backward to a
supply pump through a suction line.
[0013] According to various aspects of the present invention, a
urea backflow prevention apparatus of Selective Catalytic Reduction
(SCR) system that injects a urea aqueous solution to an exhaust
pipe may include a urea tank storing the urea aqueous solution, a
nozzle being installed on the exhaust pipe and injecting the urea
aqueous solution into the exhaust pipe, a supply pump pressurizing
the urea aqueous solution in order to inject the urea aqueous
solution from the nozzle to the exhaust pipe, a suction line
supplying the urea aqueous solution stored in the urea tank to the
supply pump by connecting the urea tank and the supply pump, a
pressure line delivering the urea aqueous solution pressurized at
the supply pump to the nozzle by connecting the supply pump and the
nozzle, and a return line collecting urea aqueous solution not
injected at the nozzle to the urea tank by connecting the supply
pump and the urea tank.
[0014] The urea backflow prevention apparatus of SCR may further
include a shut-off valve disposed on the suction line and opening
and closing the suction line.
[0015] The urea backflow prevention apparatus of SCR may further
include a urea detection device being provided in any one or more
of the supply pump or the pressure line, and detecting whether the
urea aqueous solution exists in any one or more of the supply pump
or the pressure line after the operation of the SCR system is
terminated.
[0016] The urea backflow prevention apparatus of SCR may further
include a control unit that receives a signal of whether the urea
aqueous solution exists in any one or more of the supply pump or
the pressure line from the urea detection device and transmits a
signal for the shut-off valve to open and close the suction line
after the operation of the SCR system is terminated.
[0017] The urea tank may include a ventilating opening opened to
atmosphere.
[0018] The return line may be formed to be shorter than the suction
line so that a lower part of the return line may be continuously
positioned on the surface of the urea aqueous solution inside of
the urea tank.
[0019] According to various aspects of the present invention, a
control method for a urea backflow prevention apparatus of
Selective Catalytic Reduction (SCR) may include an engine stop
determination step by a control unit of determining whether an
engine of a vehicle is stopped, a urea collection step of
collecting a urea aqueous solution inside of a pressure line, a
supply pump and a suction line by operating the supply pump in the
reverse direction, when it is determined that the engine is stopped
at the engine stop determination step, a urea collection completion
determination step of determining whether the collection of the
urea aqueous solution has been completed by the control unit
receiving a signal on whether the urea aqueous solution exists in
any one or more of the supply pump or the pressure line from a urea
detection device, after the urea collection step, and a shut-off
valve closure step of closing a shut-off valve by transmitting a
signal from the control unit to the shut-off valve, when it is
determined by the control unit that the collection of the urea
aqueous solution has been completed, after the urea collection
completion determination step.
[0020] The control method for the urea backflow prevention
apparatus of SCR may further include an engine operation
determination step of determining whether the engine is operated
again by the control unit, after the shut-off valve closure
step.
[0021] The control method for the urea backflow prevention
apparatus of SCR may, further include a shut-off valve open step of
opening the shut-off valve by transmitting a signal from the
control unit to the shut-off valve, when it is determined by the
control unit that the engine is operated again at the engine
operation determination step.
[0022] As described above, according to the present invention,
breakage of a supply pump by freezing of a urea aqueous solution
flowed backward may be prevented.
[0023] It is understood that the term "vehicle" or "vehicular" or
other similar terms as used herein is inclusive of motor vehicles
in general such as passenger automobiles including sports utility
vehicles (SUV), buses, trucks, various commercial vehicles,
watercraft including a variety of boats and ships, aircraft, and
the like, and includes hybrid vehicles, electric vehicles, plug-in
hybrid electric vehicles, hydrogen-powered vehicles and other
alternative fuel vehicles (e.g., fuel derived from resources other
than petroleum). As referred to herein, a hybrid vehicle is a
vehicle that has two or more sources of power, for example, both
gasoline-powered and electric-powered vehicles.
[0024] The methods and apparatuses of the present invention have
other features and advantages which will be apparent from or are
set forth in more detail in the accompanying drawings, which are
incorporated herein, and the following Detailed Description, which
together serve to explain certain principles of the present
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1A and FIG. 1B are views illustrating a SCR system
according to the related art.
[0026] FIG. 2A and FIG. 2B are views illustrating a problem of the
SCR system according to the related art.
[0027] FIG. 3 is a view illustrating an exemplary urea backflow
prevention apparatus of SCR according to the present invention.
[0028] FIG. 4A and FIG. 4B are views illustrating an operation of
the exemplary urea backflow prevention apparatus of SCR according
to the present invention.
[0029] FIG. 5 is a flow chart of an exemplary control method of a
urea backflow prevention apparatus of SCR according to the present
invention.
[0030] It should be understood that the appended drawings are not
necessarily to scale, presenting a somewhat simplified
representation of various features illustrative of the basic
principles of the invention. The specific design features of the
present invention as disclosed herein, including, for example,
specific dimensions, orientations, locations, and shapes will be
determined in part by the particular intended application and use
environment.
DETAILED DESCRIPTION
[0031] Reference will now be made in detail to various embodiments
of the present invention(s), examples of which are illustrated in
the accompanying drawings and described below. While the
invention(s) will be described in conjunction with exemplary
embodiments, it will be understood that the present description is
not intended to limit the invention(s) to those exemplary
embodiments. On the contrary, the invention(s) is/are intended to
cover not only the exemplary embodiments, but also various
alternatives, modifications, equivalents and other embodiments,
which may be included within the spirit and scope of the invention
as defined by the appended claims.
[0032] FIG. 3 is a view illustrating a urea backflow prevention
apparatus of SCR according to various embodiments of the present
invention. Referring to FIG. 3, the urea backflow prevention
apparatus of SCR according to various embodiments of the present
invention may include a urea tank 10, a nozzle 20, a supply pump
30, a suction line 40, a pressure line 50, a return line 60, a
shut-off valve 70, a urea detection device 80 and control unit
90.
[0033] The urea tank 10 may store a urea aqueous solution. The urea
tank 10 may include a ventilating opening 11. The ventilating
opening 11 may perform a role of discharging the inside air of the
urea tank 10. Moreover, as described later, the operation of the
SCR system is terminated and after the collecting the urea aqueous
solution is completed, the internal pressure of the SCR system may
be maintained as atmospheric pressure and equilibrium by the
ventilating opening 11.
[0034] The nozzle 20 may be installed on the exhaust pipe and
perform a role of injecting the urea aqueous solution to the
exhausted pipe.
[0035] The supply pump 30 may perform a role of pressuring the urea
aqueous solution so that the urea aqueous solution is injected from
the nozzle 20 to the exhaust pipe. Furthermore, as described later,
the supply pump 30 may operate for collecting the urea aqueous
solution in the reverse direction after the operation of the SCR
system is terminated such that it may perform a role of collecting
the urea aqueous solution inside of the system of SCR to the urea
tank 10.
[0036] The suction line 40 may connect the supply pump 30 and the
urea tank 10. Thus, the suction line 40 may perform a role of
supplying the urea aqueous solution stored in the urea tank 10 to
the supply pump 30. To this end, a lower part of the suction line
40 is preferably positioned below the surface of the urea aqueous
solution stored in the urea tank 10.
[0037] The pressure line 50 may connect the nozzle 20 and the
supply pump 30. Thus, the pressure line 50 may perform a role of
delivering the urea aqueous solution pressurized at the supply pump
30 to the nozzle 20.
[0038] The return line 60 may connect the urea tank 10 and the
supply pump 30. Thus, the return line 60 may perform a role of
collecting the urea aqueous solution not injected from the nozzle
20. The return line 60 may be formed to be shorter than the suction
line 40 so that the lower part of the return line 60 is always
preferably positioned on the surface of the urea aqueous solution
inside of the urea tank 10.
[0039] The shut-off valve 70 may be disposed on the suction line
40. Accordingly, the shut-off valve 70 may perform a role of
opening and closing the suction line 40. The shut-off valve 70 may
close the suction line 40 after the operation of the SCR (Selective
Catalytic Reduction) system is terminated so that it may prevent a
breakage of the supply pump 30 when the urea aqueous solution
inside of the urea tank 10 flows backward to the supply pump 30
through the suction line 40 (refer to FIG. 2B) and the urea aqueous
solution flowed backward is frozen.
[0040] The urea detection device 80 may be provided on any one or
more of the supply pump 30 or the pressure line 50. The urea
detection device 80 detects whether the urea aqueous solution
exists in any one or more of the supply pump 30 or the pressure
line 50 after the operation of the SCR (Selective Catalytic
Reduction) system is terminated. Accordingly, the urea detection
device 80 may perform a role of detecting whether all urea aqueous
solution is collected to the urea tank 10 after the operation of
the SCR (Selective Catalytic Reduction) system is terminated.
[0041] The control unit 90 may receive a signal of whether the urea
aqueous solution exists in any one or more of the supply pump 30 or
the pressure line 50 from the urea detection device 80 after the
operation of the SCR (Selective Catalytic Reduction) system is
terminated. Also, the control unit 90 may transmit a signal in
order that the shut-off valve 70 opens and closes the suction line
40.
[0042] FIG. 4A and FIG. 4B are views illustrating an operation of
the urea backflow prevention apparatus of SCR according to various
embodiments of the present invention. Referring FIG. 4A, during
normal operation of the SCR system, the shut-off valve 70 is opened
and the supply pump 30 is operated in the forward direction. Thus,
the urea aqueous solution stored in the urea tank 10 is moved to
the supply pump 30 along the suction line 40 and the urea aqueous
solution pressurized at the urea supply pump 30 is supplied to the
nozzle 20 along the pressure line 50 and injected into the exhaust
pipe. At this time, the urea aqueous solution which might not be
injected into the exhaust pipe is again collected to the urea tank
10 along return line 60.
[0043] Also, when the urea aqueous solution is collected, the
shut-off valve 70 is opened and the supply pump 30 is operated in
the reverse direction. Accordingly, the urea aqueous solution
remaining in the pressure line 50, the supply pump 30 or the
suction line 40 is again collected to the urea tank 10.
[0044] Referring to FIG. 4B, after the operation of the SCR system
and the collecting of the urea aqueous solution have been
completed, the shut-off valve 70 is closed. Accordingly, since the
suction line 40 is closed, the urea aqueous solution does not flow
backward unlike the related art even though the temperature of the
SCR system falls down.
[0045] FIG. 5 is a flow chart of a control method of the urea
backflow prevention apparatus of SCR according to various
embodiments of the present invention. Referring to FIG. 5, a
control method for the urea backflow prevention apparatus of SCR in
accordance with another embodiment of the present invention may
include an engine stop determination step S100, a urea collection
step S200, a urea collection completion determination step S300, a
shut-off valve closure step S400, the engine operation
determination step S500 and the shut-off valve open step S600.
[0046] The engine stop determination step S100 is a step of
determining whether an engine of a vehicle is stopped. After the
engine is stopped, the urea aqueous solution is collected only when
the exhaust gas is not discharged.
[0047] The urea collection step S200 is a step of collecting the
urea aqueous solution inside of the pressure line 50, the supply
pump 30 and the suction line 40 by operating the supply pump 30 in
the reverse direction, when it is determined that the engine is
stopped at the engine stop determination step S100. The purpose of
collecting the urea aqueous solution is to prevent breakage of
parts of the SCR system because the volume of the urea is increased
due to freezing on the spot when the temperature is lowered in the
winter.
[0048] The urea collection completion determination step S300 is a
step of determining whether the collection of the urea aqueous
solution has been completed by the control unit 90 receiving the
signal on whether the urea aqueous solution exists in any one or
more of the supply pump 30 or the pressure line 50 from the urea
detection device 80, after the urea collection step S200.
[0049] The shut-off valve closure step S400 is a step of closing
the shut-off valve 70 by transmitting the signal from the control
unit 90 to the shut-off valve 70, when it is determined that the
collection of the urea aqueous solution has been completed, after
the urea collection completion determination step S300.
Accordingly, since the suction line 40 is closed, the urea aqueous
solution does not flow backward unlike the related art even though
the temperature of the SCR system drops.
[0050] The engine operation determination step S500 is a step of
determining whether the engine operates again at the control unit
90, after the shut-off valve closure step S400. Also, the shut-off
valve open step S600 is a step of opening the shut-off valve 70 by
transmitting the signal from the control unit 90 to the shut-off
valve 70, when the control unit 90 determines that the engine is
operated again at the engine operation determination step S500.
When the engine is restarted, since the urea aqueous solution in
the exhaust pipe is again injected in order to purify NOx in the
exhaust gas, it is determined whether the engine restarts. In
addition, when the engine is restarted, the shut-off valve 70 is
re-opened in order to inject the urea aqueous solution in the
exhaust pipe and the urea aqueous solution stored in the urea tank
10 is supplied to the supply pump 30.
[0051] For convenience in explanation and accurate definition in
the appended claims, the terms "upper" or "lower", "inner" or
"outer" and etc. are used to describe features of the exemplary
embodiments with reference to the positions of such features as
displayed in the figures.
[0052] The foregoing descriptions of specific exemplary embodiments
of the present invention have been presented for purposes of
illustration and description. They are not intended to be
exhaustive or to limit the invention to the precise forms
disclosed, and obviously many modifications and variations are
possible in light of the above teachings. The exemplary embodiments
were chosen and described in order to explain certain principles of
the invention and their practical application, to thereby enable
others skilled in the art to make and utilize various exemplary
embodiments of the present invention, as well as various
alternatives and modifications thereof. It is intended that the
scope of the invention be defined by the Claims appended hereto and
their equivalents.
* * * * *