U.S. patent application number 14/313912 was filed with the patent office on 2015-06-18 for apparatus and method for controlling regeneration in exhaust emission control device.
This patent application is currently assigned to Hyundai Motor Company. The applicant listed for this patent is Hyundai Motor Company, Kia Motors Corp.. Invention is credited to Choong II Kwon, Won Soon Park.
Application Number | 20150167530 14/313912 |
Document ID | / |
Family ID | 53192715 |
Filed Date | 2015-06-18 |
United States Patent
Application |
20150167530 |
Kind Code |
A1 |
Kwon; Choong II ; et
al. |
June 18, 2015 |
APPARATUS AND METHOD FOR CONTROLLING REGENERATION IN EXHAUST
EMISSION CONTROL DEVICE
Abstract
A method and an apparatus for controlling regeneration of an
exhaust emission control device in which a diesel particulate
filter (DPF) may be installed at a back stage of a reducing agent
supply apparatus may include measuring temperature of a front stage
of the DPF at the time of supplying a reducing agent, comparing a
temperature value measured at the front stage of the DPF with a
temperature modeling value of the front stage of the DPF, and
controlling the regeneration of the DPF by comparing a difference
between the temperature value and the temperature modeling value
with a reference variation.
Inventors: |
Kwon; Choong II; (Gunpo-si,
KR) ; Park; Won Soon; (Seongnam-si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hyundai Motor Company
Kia Motors Corp. |
Seoul
Seoul |
|
KR
KR |
|
|
Assignee: |
Hyundai Motor Company
Seoul
KR
Kia Motors Corp.
Seoul
KR
|
Family ID: |
53192715 |
Appl. No.: |
14/313912 |
Filed: |
June 24, 2014 |
Current U.S.
Class: |
60/274 ;
60/286 |
Current CPC
Class: |
F01N 3/2066 20130101;
Y02T 10/40 20130101; Y02T 10/24 20130101; F01N 3/023 20130101; Y02T
10/47 20130101; F01N 2900/1602 20130101; F01N 3/035 20130101; F01N
9/005 20130101; Y02T 10/12 20130101; F01N 9/002 20130101 |
International
Class: |
F01N 9/00 20060101
F01N009/00; F01N 3/023 20060101 F01N003/023 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 18, 2013 |
KR |
10-2013-0157848 |
Claims
1. A method for controlling regeneration of an exhaust emission
control device in which a diesel particulate filter (DPF) is
installed at a back stage of a reducing agent supply apparatus, the
method comprising: measuring temperature of a front stage of the
DPF at a time of supplying a reducing agent by the reducing agent
supply apparatus while regenerating the DPF; comparing a
temperature value measured at the front stage of the DPF with a
temperature modeling value of the front stage of the DPF depending
on the regeneration of the DPF based on a map showing a
relationship between the temperature value and the temperature
modeling value; and controlling the regeneration of the DPF by
comparing a difference between the temperature value and the
temperature modeling value with a reference variation and selecting
the temperature value or the temperature modeling value as the
temperature of the front stage of the DPF depending on the
difference.
2. The method of claim 1, wherein in the controlling of the
regeneration, when the difference between the temperature value and
the temperature modeling value exceeds the reference variation, the
DPF is regenerated based on the temperature modeling value.
3. The method of claim 1, wherein in the controlling of the
regeneration, when the difference between the temperature value and
the temperature modeling value is equal to or less than the
reference variation, the DPF is regenerated based on the
temperature value.
4. The method of claim 1, wherein the DPF is coated with a
selective catalytic reduction (SCR) catalyst.
5. The method of claim 1, wherein the front stage of the DPF is
provided with a temperature sensor to measure the temperature of
the front stage of the DPF.
6. An apparatus for controlling regeneration of an exhaust emission
control device, comprising: a temperature sensor configured to
measure a temperature of a front stage of a diesel particulate
filter (DPF); and a control unit configured to compare a
temperature value measured at the front stage of the DPF with a
temperature modeling value of the front stage of the DPF depending
on an active regeneration of the DPF based on a map showing a
relationship between the temperature value and the temperature
modeling value and to control regeneration of the DPF by comparing
a difference between the temperature value and the temperature
modeling value with a reference variation at a time of supplying
the reducing agent by a reducing agent supply apparatus while
actively regenerating the DPF to select the temperature value or
the temperature modeling value as the temperature of the front
stage of the DPF depending on the difference.
7. The apparatus of claim 6, wherein in controlling of the
regeneration, when the difference between the temperature value and
the temperature modeling value exceeds the reference variation, the
DPF is regenerated based on the temperature modeling value.
8. The apparatus of claim 6, wherein in controlling of the
regeneration, when the difference between the temperature value and
the temperature modeling value is equal to or less than the
reference variation, the DPF is regenerated based on the
temperature value.
9. The apparatus of claim 6, wherein the DPF is coated with a
selective catalytic reduction (SCR) catalyst.
Description
CROSS-REFERENCE(S) TO RELATED APPLICATION
[0001] The present application claims priority of Korean Patent
Application Number 10-2013-0157848 filed on Dec. 18, 2013, the
entire contents of which application 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 regeneration technology
of an exhaust emission control device, and more particularly, to an
apparatus and a method for controlling regeneration in an exhaust
emission control device capable of stably performing DPF
regeneration at the time of the DPF regeneration in an S-DPF
system.
[0004] 2. Description of Related Art
[0005] To cope with a tightening of exhaust regulations on
passenger diesel car diesel, in particular, EURO6 and North
American markets, it is essential to reduce NOx. In particular, in
order for a passenger car to meet an exhaust regulation of the
EURO6, there is a need to reduce NOx emission to about 56%, that
is, NOx emission from 0.18 g/km which is the exhaust regulation of
the existing EURO5 to 0.08 g/km.
[0006] To cope with the necessity of reduction in NOx, an exhaust
emission control device called as lean NOx trap (LNT) or selective
catalytic reduction (SCR) to purity NOx emitted from an engine has
been developed or applied worldwide.
[0007] Among those, the SCR system, which is a method for purifying
NOx by supplying a separate reducing agent (generally, urea) in
front of an SCR catalyst, may be an exhaust emission control device
having very large NOx purification efficiency without sacrificing
fuel efficiency of a vehicle.
[0008] The SCR system has a configuration in which a diesel
oxidation catalyst (DOC), a diesel particulate filter (DPF), a
reducing agent supply apparatus, and an SCR catalyst are generally
disposed at a back stage of an engine in order.
[0009] That is, when an appropriate quantity of reducing agent is
injected into an exhaust pipe by estimating a concentration of NOx
emitted at the time of an operation of the engine based on modeling
or measuring the concentration of NOx using a sensor, the injected
reducing agent serves to reduce and purify the NOx while reacting
with the SCR catalyst.
[0010] Meanwhile, a passenger car diesel engine has excellent fuel
efficiency but is expensive and an exhaust emission control device,
and the like for reducing NOx is additionally required. Therefore,
an exhaust emission control device having reduced material cost and
weight which having high-efficiency NOx purification performance is
required.
[0011] Therefore, to meet the demand, an S-DPF which is a
combination of a function of the SCR catalyst with a function of
the DPF, that is, a system in which the SCR catalyst is coated on
the DPF has been researched.
[0012] However, since the S-DPF system in which the DPF is combined
with the SCR has two functions, there are many technical problems
to overcome.
[0013] Among these problems, in particular, a problem of a
deterioration of the SCR catalyst at the time of active
regeneration due to soot generated within the DPF which is due to
heat generation at high temperature is to be overcome. Further, in
injecting urea (hereinafter, referred to as a reducing agent) for
purifying NOx to a front stage of the DPF, there is a difficulty in
injecting the reducing agent at the time of the high-temperature
active regeneration.
[0014] In other words, unlike the existing SCR system, the S-DPF
system has a configuration in which the diesel oxidation catalyst
(DOC), the reducing agent supply apparatus, and the S-DPF (filter
in which the SCR catalyst is coated on the DPF) are disposed at the
back stage of the engine in order. Here, the soot accumulated
within the S-DPF also needs to be periodically combusted and
regenerated, like a general DPF.
[0015] In particular, to meet the tightened exhaust regulation,
there is a need to inject the reducing agent during the DPF
regeneration so as to reduce NOx excessively generated at the time
of the DPF regeneration.
[0016] However, since a larger quantity of NOx is emitted during
the DPF regeneration than during the general driving, a larger
quantity of reducing agent needs to be injected to regenerate the
NOx during the DPF regeneration.
[0017] Here, an injection quantity of the reducing agent varies
depending on a NOx quantity, temperature, and the like, in
particular, a larger quantity of reducing agent is oxidized before
the reducing agent reacts with the SCR catalyst due to the high
temperature characteristic depending on the regeneration even
though the reducing agent is injected at the time of the DPF
regeneration and thus the reducing agent may not be used, and a
larger quantity of reducing agent is injected due to a larger
quantity of NOx.
[0018] However, when a larger quantity of reducing agent is
injected at the time of the DPF regeneration, the injected reducing
agent contacts a temperature sensor installed at the front stage of
the DPF in the state of an aqueous solution, and thus a precise
temperature value of the front stage of the DPF may be
distorted.
[0019] That is, at the time of the regeneration of the DPF, a
governor keeps a targeted regenerating target temperature using a
temperature value measured by the temperature sensor at the front
stage of the DPF. In the S-DPF system, a large quantity of injected
reducing agent contacts the temperature sensor to temporarily
reduce the temperature recognized by the temperature sensor. In
this case, to adjust the target temperature in the ECU, an
injection quantity of fuel is increased to adjust the
temperature.
[0020] That is, the temperature of actual exhaust gas already
reaches temperature which may be regenerated but an inlet
temperature of the DPF is suddenly increased due to the temporary
distortion of the temperature sensor, such that the DPF may be
damaged and the temperature of the temperature sensor may be
continuously distorted, thereby causing the incomplete
regeneration.
[0021] The information disclosed in this Background of the
Invention section is only for enhancement of understanding of the
general background of the invention and should not be taken as an
acknowledgement or any form of suggestion that this information
forms the prior art already known to a person skilled in the
art.
BRIEF SUMMARY
[0022] Various aspects of the present invention are directed to
providing an apparatus and a method for controlling regeneration of
an exhaust emission control device capable of stably regenerating
DPF by removing a temperature distortion at a front stage of DPF at
the time of injecting a reducing agent during DPF regeneration.
[0023] A method for controlling regeneration of an exhaust emission
control device in which a diesel particulate filter (DPF) is
installed at a back stage of a reducing agent supply apparatus, may
include measuring temperature of a front stage of the DPF at a time
of supplying a reducing agent by the reducing agent supply
apparatus while regenerating the DPF, comparing a temperature value
measured at the front stage of the DPF with a temperature modeling
value of the front stage of the DPF depending on the regeneration
of the DPF based on a map showing a relationship between the
temperature value and the temperature modeling value, and
controlling the regeneration of the DPF by comparing a difference
between the temperature value and the temperature modeling value
with a reference variation and selecting the temperature value or
the temperature modeling value as the temperature of the front
stage of the DPF depending on the difference.
[0024] In the controlling of the regeneration, when the difference
between the temperature value and the temperature modeling value
exceeds the reference variation, the DPF is regenerated based on
the temperature modeling value.
[0025] In the controlling of the regeneration, when the difference
between the temperature value and the temperature modeling value is
equal to or less than the reference variation, the DPF is
regenerated based on the temperature value.
[0026] The DPF is coated with a selective catalytic reduction (SCR)
catalyst.
[0027] The front stage of the DPF is provided with a temperature
sensor to measure the temperature of the front stage of the
DPF.
[0028] In another aspect of the present invention, an apparatus for
controlling regeneration of an exhaust emission control device, may
include a temperature sensor configured to measure a temperature of
a front stage of a diesel particulate filter (DPF), and a control
unit configured to compare a temperature value measured at the
front stage of the DPF with a temperature modeling value of the
front stage of the DPF depending on an active regeneration of the
DPF based on a map showing a relationship between the temperature
value and the temperature modeling value and to control
regeneration of the DPF by comparing a difference between the
temperature value and the temperature modeling value with a
reference variation at a time of supplying the reducing agent by a
reducing agent supply apparatus while actively regenerating the DPF
to select the temperature value or the temperature modeling value
as the temperature of the front stage of the DPF depending on the
difference, wherein in controlling of the regeneration, when the
difference between the temperature value and the temperature
modeling value exceeds the reference variation, the DPF is
regenerated based on the temperature modeling value, and wherein in
controlling of the regeneration, when the difference between the
temperature value and the temperature modeling value is equal to or
less than the reference variation, the DPF is regenerated based on
the temperature value.
[0029] 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
[0030] FIG. 1 is a diagram for describing a configuration of an
S-DPF system according to an exemplary embodiment of the present
invention.
[0031] FIG. 2 is a diagram for describing a method for controlling
a control flow of a control method according to an exemplary
embodiment of the present invention.
[0032] FIG. 3 is a diagram illustrating a temperature profile at
the time of injecting a reducing agent during DPF regeneration
according to the exemplary embodiment of the present invention.
[0033] 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.
[0034] In the figures, reference numbers refer to the same or
equivalent parts of the present invention throughout the several
figures of the drawing.
DETAILED DESCRIPTION
[0035] 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.
[0036] Exemplary embodiments of the present invention will be
described below in detail with reference to the accompanying
drawings.
[0037] FIG. 1 is a diagram for describing a configuration of a DPF
system according to an exemplary embodiment of the present
invention, FIG. 2 is a diagram for describing a method for
controlling a control flow of a control method according to an
exemplary embodiment of the present invention, and FIG. 3 is a
diagram illustrating a temperature profile at the time of injecting
a reducing agent during DPF regeneration according to the exemplary
embodiment of the present invention.
[0038] Prior to describing a method for controlling regeneration of
an exhaust emission control device according to an exemplary
embodiment of the present invention, a configuration of an exhaust
emission control device according to an exemplary embodiment of the
present invention will be described.
[0039] Referring to FIG. 1, the exhaust emission control device
according to the exemplary embodiment of the present invention is a
DPF system and may have a configuration in which a DOC, a reducing
agent supply apparatus 5, and a DPF 3 are disposed at a back stage
of an engine 1 in order.
[0040] In this configuration, the DPF 3 may be an S-DPF which is
formed by being coated with an SCR catalyst.
[0041] A method for controlling regeneration of an exhaust emission
control device according to the exemplary embodiment of the present
invention is configured to largely include measuring (S10),
comparing (S20), and controlling regeneration (S30).
[0042] Describing in detail the exemplary embodiment of the present
invention with reference to FIGS. 2 and 3, a method for controlling
regeneration of an exhaust emission control device in which the DPF
3 is installed at a back stage of the reducing agent supply
apparatus 5 includes: measuring temperature of a front stage of the
DPF 3 at the time of supplying a reducing agent by the reducing
agent supply apparatus 5 while actively regenerating the DPF 3
(S10), comparing a temperature value T1 measured at the front stage
of the DPF 3 with a temperature modeling value T2 of the front
stage of the DPF 3 depending on the regeneration of the DPF 3 based
on a map showing the relationship between the temperature value T1
and the temperature modeling value T2 (S20), and controlling the
regeneration of the DPF 3 by comparing a difference between the
temperature value T1 and the temperature modeling value T2 with a
reference variation .DELTA.T to select the temperature value T1 or
the temperature modeling value T2 as the temperature of the front
stage of the DPF 3 depending on the difference (S30).
[0043] In this configuration, the DPF 3 may be the S-DPF coated
with the SCR catalyst as described above. Further, a temperature
sensor 7 is disposed at the front stage of the DPF 3 to be able to
measure the temperature of the front stage of the DPF 3.
[0044] That is, during the driving of a vehicle, an active
regeneration time is determined by monitoring regeneration related
variables of the DPF 3 and estimating a soot quantity within the
DPF 3 due to the variable. At the time of determining the active
regeneration time, the active regeneration is performed while
controlling post-fuel injection and air quantity and at the same
time, a reducing agent (urea) is injected to the DPF 3 side through
the reducing agent supply apparatus 5 to remove NOx.
[0045] In this case, the map showing the relationship of the
temperature modeling value T2 of the front stage of the DPF3
depending on the active regeneration of the DPF 3 may be set in a
control unit (ECU) 9 according to the exemplary embodiment of the
present invention.
[0046] Therefore, the exemplary embodiment of the present invention
calculates the difference between the temperature value T1 measured
at the front stage of the DPF 3 and the temperature modeling value
T2 at the time of supplying the reducing agent along with the
active regeneration of the DPF 3. The temperature value T1 measured
by the temperature sensor 7 is selected as the temperature of the
front stage of the DPF 3 used to control the post-fuel injection
quantity at the time of the active regeneration depending on the
size of the calculated difference value or the temperature modeling
value T2 is selected on the map and thus is used to control the
fuel injection quantity.
[0047] Therefore, at the time of injecting the reducing agent
during the regeneration of the DPF 3, the temperature distortion at
the front stage of the DPF 3 due to the reducing agent is
prevented, such that the post-fuel injection quantity depending on
the regeneration of the DPF3 is precisely controlled, thereby
increasing the regeneration efficiency of the DPF 3.
[0048] In particular, referring to FIG. 3, in the controlling of
the regeneration (S30) according to the exemplary embodiment of the
present invention, when the difference between the temperature
value T1 and the temperature modeling value T2 exceeds the
reference variation .DELTA.T, the DPF 3 may be controlled to be
actively regenerated based on the temperature modeling value
T2.
[0049] Further, in the controlling of the regeneration (S30), when
the difference between the temperature value T1 and the temperature
modeling value T2 is equal to or less than the reference variation
.DELTA.T, the DPF 3 may be controlled to be actively regenerated
based on the temperature value T1.
[0050] That is, at the time of injecting the reducing agent during
the regeneration of the DPF 3, when the difference between the
temperature value T1 measured by the temperature sensor 7 and the
temperature modeling value T2 is larger than the reference
variation .DELTA.T, the post-fuel injection quantity is controlled
based on the temperature modeling value T2 to prevent the serious
temperature distortion at the front stage of the DPF 3 and when the
difference between the temperature value T1 measured by the
temperature sensor 7 and the temperature modeling value T2 is
smaller than the reference variation .DELTA.T, the temperature
distortion at the front stage of the DPF 3 is relatively small, and
thus the post-fuel injection quantity is controlled based on the
actually measured temperature value T1.
[0051] Therefore, the sudden increase in temperature of the front
stage of the DPF 3 may be prevented by preventing the signal
distortion of the temperature sensor 7 at the front stage of the
DPF 3, thereby preventing the DPF from being damaged, the
regeneration efficiency of the DPF 3 may be increased by precisely
controlling the temperature of the front stage of the DPF, and the
fuel quantity during the regeneration may be reduced by precisely
controlling the post-fuel injection quantity to improve the fuel
efficiency.
[0052] Meanwhile, the apparatus for controlling regeneration of an
exhaust emission control device according to the exemplary
embodiment of the present invention is configure to largely include
the temperature sensor 7 and the control unit 9.
[0053] In detail, the apparatus for controlling regeneration of an
exhaust emission control device includes: the temperature sensor 7
configured to measure the temperature of the front stage of the DPF
3, and the control unit configured to compare the temperature value
T1 measured at the front stage of the DPF 3 with the temperature
modeling value T2 of the front stage of the DPF 3 depending on the
active regeneration of the DPF 3 based on the map showing the
relationship between the temperature value T1 and the temperature
modeling value T2 and control the regeneration of the DPF 3 by
comparing the difference between the temperature value T1 and the
temperature modeling value T2 with the reference variation .DELTA.T
at the time of supplying the reducing agent by the reducing agent
supply apparatus 5 while actively regenerating the DPF 3 to select
the temperature value T1 or the temperature modeling value T2 as
the temperature of the front stage of the DPF 3 depending on the
difference.
[0054] According to the exemplary embodiments of the present
invention, the sudden increase in temperature of the front stage of
the DPF may be prevented by preventing the signal distortion of the
temperature sensor at the front stage of the DPF at the time of
injecting the reducing agent during the DPF regeneration, thereby
preventing the DPF from being damaged, the regeneration efficiency
of the DPF may be increased by precisely controlling the
temperature of the front stage of the DPF, and the fuel quantity
during the regeneration may be reduced by precisely controlling the
post-fuel injection quantity to improve the fuel efficiency.
[0055] For convenience in explanation and accurate definition in
the appended claims, the terms "upper", "lower", "inner" and
"outer" are used to describe features of the exemplary embodiments
with reference to the positions of such features as displayed in
the figures.
[0056] 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.
* * * * *