KR20220017034A - System and method for removing DOC blockage in exhaust system - Google Patents

System and method for removing DOC blockage in exhaust system Download PDF

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KR20220017034A
KR20220017034A KR1020200096850A KR20200096850A KR20220017034A KR 20220017034 A KR20220017034 A KR 20220017034A KR 1020200096850 A KR1020200096850 A KR 1020200096850A KR 20200096850 A KR20200096850 A KR 20200096850A KR 20220017034 A KR20220017034 A KR 20220017034A
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doc
differential pressure
dpf
exhaust
exhaust temperature
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KR1020200096850A
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Korean (ko)
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최성무
조지호
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현대자동차주식회사
기아 주식회사
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N11/00—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
    • F01N3/023—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/105—General auxiliary catalysts, e.g. upstream or downstream of the main catalyst
    • F01N3/106—Auxiliary oxidation catalysts
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2006—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating
    • F01N3/2033—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating using a fuel burner or introducing fuel into exhaust duct
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N9/00—Electrical control of exhaust gas treating apparatus
    • F01N9/002—Electrical control of exhaust gas treating apparatus of filter regeneration, e.g. detection of clogging
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2550/00—Monitoring or diagnosing the deterioration of exhaust systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
    • F01N2560/08—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being a pressure sensor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
    • F01N2900/04—Methods of control or diagnosing
    • F01N2900/0416—Methods of control or diagnosing using the state of a sensor, e.g. of an exhaust gas sensor
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Materials Engineering (AREA)
  • Processes For Solid Components From Exhaust (AREA)

Abstract

The present invention relates to a system for removing blockage of a DOC in an exhaust system to diagnose and remove blockage of a front end of a DOC through a structural change of an exhaust system, and a method therefor. The present invention comprises: the DOC and a DPF sequentially arranged along an exhaust line; a differential pressure sensor measuring differential pressure between the front end of the DOC and a rear end of the DPF; and a controller controlling to raise exhaust temperature of the front end of the DOC when a difference between a differential pressure model value of the DOC and differential pressure of the DOC calculated based on the differential pressure measured by the differential pressure sensor exceeds a set value.

Description

배기시스템의 DOC 막힘 제거시스템 및 방법{System and method for removing DOC blockage in exhaust system}System and method for removing DOC blockage in exhaust system

본 발명은 배기시스템의 구조 변경을 통해 DOC 전단의 막힘을 진단 및 제거하도록 한 배기시스템의 DOC 막힘 제거 시스템 및 방법에 관한 것이다.The present invention relates to a DOC clogging system and method for diagnosing and removing a DOC front end blockage by changing the structure of the exhaust system.

기존의 배기시스템의 경우, DPF 전/후단 사이에 차압센서를 설치하고, 차압센서에서 검출한 차압값을 기반으로 DPF에 포집된 Soot 포집량을 예측한다.In the case of the existing exhaust system, a differential pressure sensor is installed between the front and rear ends of the DPF, and the amount of soot collected in the DPF is predicted based on the differential pressure value detected by the differential pressure sensor.

한편, 엔진에서 배출되는 배기가스에는 미연소 연료, 접착성이 강한 soot 성분, 엔진오일 성분 등의 연소생성물이 포함되어 있는데, 이들 연소생성물이 DOC 전단에 붙게 되면서 DOC 전단을 막는 현상이 발생할 수 있다.On the other hand, the exhaust gas emitted from the engine contains combustion products such as unburned fuel, soot component with strong adhesiveness, and engine oil component. .

이처럼, DOC 막힘이 발생하게 되면, 출력저하, 연비 악화, 엔진/후처리 장치 고장으로 이어지게 된다.As such, when the DOC is clogged, it leads to a decrease in output, deterioration of fuel efficiency, and failure of the engine/after-treatment device.

하지만, DPF의 soot 포집량을 예측하는 기존의 배기시스템으로는 DOC 전단의 막힘을 판단할 수 없어, DOC 막힘을 진단 및 제거할 수 있는 방안이 요구되고 있다.However, it is not possible to determine the clogging of the DOC front end with the existing exhaust system that predicts the soot collection amount of the DPF, so a method for diagnosing and removing the DOC clogging is required.

상기의 배경기술로서 설명된 사항들은 본 발명의 배경에 대한 이해 증진을 위한 것일 뿐, 이 기술분야에서 통상의 지식을 가진 자에게 이미 알려진 종래기술에 해당함을 인정하는 것으로 받아들여져서는 안 될 것이다.The matters described as the background art above are only for improving the understanding of the background of the present invention, and should not be taken as acknowledging that they correspond to the prior art known to those of ordinary skill in the art.

KR 10-1575478 B1KR 10-1575478 B1

본 발명은 전술한 바와 같은 문제점을 해결하기 위하여 안출한 것으로, 배기시스템의 구조 변경을 통해 DOC 전단의 막힘을 진단 및 제거하도록 한 배기시스템의 DOC 막힘 제거 시스템 및 방법을 제공하는 데 있다.The present invention has been devised to solve the above-described problems, and an object of the present invention is to provide a DOC clogging removal system and method for diagnosing and removing the DOC front end blockage by changing the structure of the exhaust system.

상기와 같은 목적을 달성하기 위한 본 발명의 구성은, 배기라인을 따라 순차적으로 배치된 DOC 및 DPF; 상기 DOC 전단과 DPF 후단 사이의 차압을 측정하는 차압센서; 및 상기 차압센서에 의해 측정된 차압을 기반으로 계산된 DOC 차압과 DOC 차압모델값의 차이가 설정값 초과시, DOC 전단의 배기온도를 상승시키도록 제어하는 제어기;를 포함하는 것을 특징으로 할 수 있다.The configuration of the present invention for achieving the above object includes: DOC and DPF sequentially arranged along an exhaust line; a differential pressure sensor for measuring the differential pressure between the front end of the DOC and the rear end of the DPF; And when the difference between the DOC differential pressure calculated based on the differential pressure measured by the differential pressure sensor and the DOC differential pressure model value exceeds a set value, a controller that controls the exhaust temperature of the front end of the DOC to increase. .

상기 DOC 차압과 DOC 차압모델값은 DPF의 재생 직후를 기준으로 계산된 값일 수 있다.The DOC differential pressure and the DOC differential pressure model value may be values calculated based on immediately after regeneration of the DPF.

상기 DOC 차압은, DPF 재생 직후에 차압센서에 의해 측정된 차압에서 DPF 재생 직후의 DPF 차압을 감산한 값으로 계산되고; 상기 DPF 차압은, DPF의 재생 직후를 기준으로 배기유량에 따라 결정되는 모델값일 수 있다.the DOC differential pressure is calculated as a value obtained by subtracting the DPF differential pressure immediately after the DPF regeneration from the differential pressure measured by the differential pressure sensor immediately after the DPF regeneration; The DPF differential pressure may be a model value determined according to an exhaust flow rate immediately after regeneration of the DPF.

상기 설정값은 배기온도 및 배기유량에 따라 결정될 수 있다.The set value may be determined according to the exhaust temperature and the exhaust flow rate.

상기 제어기는 후분사를 통해 DOC 전단의 배기온도를 상승시킬 수 있다.The controller may increase the exhaust temperature of the front end of the DOC through the after-injection.

상기 DOC 전단의 배기온도는 soot의 연소를 위해 요구되는 온도범위로 일정시간 이상 상승시킬 수 있다.The exhaust temperature in front of the DOC may be increased to a temperature range required for soot combustion for a certain period of time or longer.

본 발명은, 배기시스템의 DOC 막힘을 제거하는 방법으로서, 제어기가, DOC 전단과 DPF 후단 사이의 차압을 검출하는 차압검출단계; 제어기가, DOC 전단과 DPF 후단 사이의 차압을 기반으로 DOC 차압을 계산하는 DOC차압 계산단계; 및 제어기가, 상기 DOC 차압과 DOC 차압모델값의 차이가 설정값 초과시, DOC 전단의 배기온도를 상승시키도록 제어하는 배기온도 상승단계;를 포함하는 것을 특징으로 할 수 있다.The present invention provides a method for removing blockage of a DOC in an exhaust system, comprising: a differential pressure detection step in which a controller detects a differential pressure between a front end of a DOC and a rear end of the DPF; a DOC differential pressure calculation step in which the controller calculates the DOC differential pressure based on the differential pressure between the front end of the DOC and the rear end of the DPF; and an exhaust temperature raising step of controlling, by the controller, to increase the exhaust temperature at the front end of the DOC when the difference between the DOC differential pressure and the DOC differential pressure model value exceeds a set value.

상기한 과제 해결수단을 통해 본 발명은, DOC + DPF의 차압 변화에 따라 DOC의 막힘을 판단하고, DOC의 막힘이 발생한 것으로 판단한 경우, DOC 전단의 온도를 상승시켜 DOC 전단 막힘을 제거하게 된다.Through the above-mentioned problem solving means, the present invention determines the clogging of the DOC according to the change in the differential pressure of DOC + DPF, and when it is determined that the clogging of the DOC has occurred, the temperature at the front end of the DOC is increased to remove the blockage of the DOC shear.

따라서, 배기시스템의 간단한 구조 변경을 통해 DOC 전단의 막힘을 진단 및 제거 가능함으로써, DOC 전단의 배압 증가에 따른 연비 및 출력감소를 줄이는 것은 물론, 배기시스템의 고장을 방지하여 배기계 내구성 및 상품성을 향상시키는 효과가 있다.Therefore, it is possible to diagnose and remove blockages at the front end of the DOC through a simple structural change of the exhaust system, thereby reducing fuel efficiency and output reduction due to an increase in back pressure at the front end of the DOC, as well as improving the durability and marketability of the exhaust system by preventing failure of the exhaust system has the effect of making

도 1은 본 발명에 따른 DOC 막힘 제거시스템을 개략적으로 도시한 도면.
도 2 및 도 3은 본 발명에서 DOC 막힘을 진단하는 원리를 설명하기 위한 도면.
도 4는 본 발명에서 DOC 막힘 정도에 따른 배기유량별 DOC 차압을 나타낸 도면.
도 5는 본 발명에서 DOC 전단의 온도를 상승시키기 위한 후분사 시기를 설명하기 위한 도면.
도 6은 본 발명에서 배기온도에 따른 DOC 막힘 제거효율을 나타낸 도면.
도 7은 본 발명에서 DOC 막힘을 제거하기 위한 방법을 전체적으로 예시한 플로우차트.1 is a view schematically showing a DOC blockage removal system according to the present invention.
2 and 3 are diagrams for explaining the principle of diagnosing DOC blockage in the present invention.
4 is a view showing the DOC differential pressure for each exhaust flow rate according to the degree of DOC clogging in the present invention.
Figure 5 is a view for explaining the post-injection timing for increasing the temperature of the front end of the DOC in the present invention.
6 is a view showing the DOC clogging removal efficiency according to the exhaust temperature in the present invention.
7 is a flowchart generally illustrating a method for clearing a DOC blockage in the present invention.

본 발명의 바람직한 실시예를 첨부된 도면에 의하여 상세히 설명하면 다음과 같다.A preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

도 1은 본 발명에 따른 DOC 막힘 제거시스템을 개략적으로 도시한 도면이다.1 is a diagram schematically showing a DOC clogging removal system according to the present invention.

도면을 참조하여 본 발명의 DOC 막힘 제거시스템을 살펴보면, 본 발명은 배기라인(1)을 따라 순차적으로 배치된 DOC(10) 및 DPF(20); 상기 DOC(10) 전단과 DPF(20) 후단 사이의 차압을 측정하는 차압센서(30); 및 상기 차압센서(30)에 의해 측정된 차압을 기반으로 계산된 DOC 차압과 DOC 차압모델값의 차이가 설정값 초과시, DOC(10) 전단의 배기온도를 상승시키도록 제어하는 제어기(40);를 포함하여 구성이 된다.Looking at the DOC clogging removal system of the present invention with reference to the drawings, the present invention is a DOC (10) and DPF (20) disposed sequentially along the exhaust line (1); a differential pressure sensor 30 for measuring the differential pressure between the front end of the DOC 10 and the rear end of the DPF 20; And when the difference between the DOC differential pressure calculated based on the differential pressure measured by the differential pressure sensor 30 and the DOC differential pressure model value exceeds a set value, a controller 40 for controlling the exhaust temperature of the front end of the DOC 10 to rise; It consists of including .

예컨대, 배기라인(1) 상에 DOC(10)(Diesel Oxidation Catalyst)가 설치되고, 상기 DOC(10)의 후단에 DPF(20)(Diesel Particulate Filter)가 설치된다.For example, a Diesel Oxidation Catalyst (DOC 10) is installed on the exhaust line 1, and a Diesel Particulate Filter (DPF 20) is installed at a rear end of the DOC 10 .

그리고, 상기 DOC(10)의 전단과 DPF(20)의 후단 사이에 차압파이프(32)가 설치되고, 상기 차압파이프(32)의 중단에 차압센서(30)가 설치됨으로써, DOC + DPF의 차압을 모니터링하게 된다.And, the differential pressure pipe 32 is installed between the front end of the DOC 10 and the rear end of the DPF 20 , and the differential pressure sensor 30 is installed at the middle of the differential pressure pipe 32 , so that the differential pressure of DOC + DPF will be monitored.

즉, 기존 배기시스템에서 차압파이프(32)의 위치만 DPF(20) 전단에서 DOC(10) 전단으로 변경하고, DOC + DPF의 차압 변화에 따라 DOC(10)의 막힘을 판단한다. 이에, DOC(10)의 막힘이 발생한 것으로 판단한 경우, DOC(10) 전단의 온도를 상승시켜 DOC(10) 전단 막힘을 제거하게 된다.That is, in the existing exhaust system, only the position of the differential pressure pipe 32 is changed from the front end of the DPF 20 to the front end of the DOC 10 , and the clogging of the DOC 10 is determined according to the change in the differential pressure of DOC + DPF. Accordingly, when it is determined that blockage of the DOC 10 has occurred, the temperature of the front end of the DOC 10 is increased to remove the blockage of the front end of the DOC 10 .

이처럼, 본 발명은 배기시스템의 간단한 구조 변경을 통해 DOC(10) 전단의 막힘을 진단 및 제거 가능함으로써, DOC(10) 전단의 배압 증가에 따른 연비 및 출력감소를 줄이는 것은 물론, 배기시스템의 고장을 방지하여 배기계 내구성 및 상품성을 향상시키게 된다.As such, the present invention can diagnose and remove blockages at the front end of the DOC 10 through a simple structural change of the exhaust system, thereby reducing fuel efficiency and output reduction due to an increase in back pressure at the front end of the DOC 10, as well as failure of the exhaust system to improve the durability and marketability of the exhaust system.

참고로, 본 발명의 예시적인 실시예에 따른 제어기(40)는 차량의 다양한 구성 요소의 동작을 제어하도록 구성된 알고리즘 또는 상기 알고리즘을 재생하는 소프트웨어 명령어에 관한 데이터를 저장하도록 구성된 비휘발성 메모리(도시되지 않음) 및 해당 메모리에 저장된 데이터를 사용하여 이하에 설명되는 동작을 수행하도록 구성된 프로세서(도시되지 않음)를 통해 구현될 수 있다. 여기서, 메모리 및 프로세서는 개별 칩으로 구현될 수 있다. 대안적으로는, 메모리 및 프로세서는 서로 통합된 단일 칩으로 구현될 수 있다. 프로세서는 하나 이상의 프로세서의 형태를 취할 수 있다.For reference, the controller 40 according to the exemplary embodiment of the present invention includes a non-volatile memory (not shown) configured to store data regarding an algorithm configured to control the operation of various components of the vehicle or software instructions for reproducing the algorithm. not) and a processor (not shown) configured to perform operations described below using data stored in the corresponding memory. Here, the memory and the processor may be implemented as separate chips. Alternatively, the memory and processor may be implemented as a single chip integrated with each other. A processor may take the form of one or more processors.

한편, 상기 DOC 차압과 DOC 차압모델값은 DPF(20)의 재생 직후를 기준으로 계산된 값일 수 있다.Meanwhile, the DOC differential pressure and the DOC differential pressure model value may be values calculated on the basis of immediately after regeneration of the DPF 20 .

즉, DPF(20)의 재생이 완료되면 DPF(20) 내에 soot가 제거된 상태가 되므로, DOC + DPF의 차압값이 DOC 단독의 차압이 되어, DOC 차압을 확보하게 된다.That is, when the regeneration of the DPF 20 is completed, soot is removed in the DPF 20 , so the differential pressure value of DOC + DPF becomes the differential pressure of the DOC alone, thereby securing the DOC differential pressure.

도 2는 배기유량과 soot 조건에 따른 DOC + DPF의 차압 및 DPF(20)의 차압을 나타낸 도면이고, 도 3은 재생이 완료된 조건에서 계산된 DOC 차압과 DOC 차압모델값을 나타낸 도면이다. 도면에 표현된 '정상'은 재생을 통해 soot가 완전 제거된 조건을 의미할 수 있다.2 is a view showing the differential pressure of DOC + DPF and the differential pressure of the DPF 20 according to the exhaust flow rate and soot condition, and FIG. 3 is a diagram showing the DOC differential pressure and the DOC differential pressure model value calculated in the condition where the regeneration is completed. 'Normal' expressed in the drawings may mean a condition in which soot is completely removed through regeneration.

이에, 도면을 참조하여 DOC 막힘을 진단하는 원리에 대해 조금 더 구체적으로 설명하면, 상기 DOC 차압은, DPF(20) 재생 직후에 차압센서(30)에 의해 측정된 차압에서 DPF(20) 재생 직후의 DPF 차압을 감산한 값으로 계산된다.Accordingly, referring to the drawings, the principle of diagnosing the DOC clogging will be described in more detail. The DOC differential pressure is the differential pressure measured by the differential pressure sensor 30 immediately after the DPF 20 is regenerated immediately after the DPF 20 is regenerated. It is calculated by subtracting the DPF differential pressure.

그리고, 상기 DPF 차압은, DPF(20)의 재생 직후를 기준으로 배기유량에 따라 결정되는 모델값에 의해 확보된다.In addition, the DPF differential pressure is secured by a model value determined according to the exhaust flow rate immediately after regeneration of the DPF 20 .

즉, DPF(20)의 재생 직후, soot가 없는 조건에서 DOC + DPF의 배압을 차압센서(30)에 의해 측정함으로써, DOC + DPF 차압을 확보하게 되고, 배기유량에 따라 DPF(20)의 차압 역시 확보하게 됨으로써, DOC 차압을 계산할 수 있게 된다. 이를 수식으로 표현하면 아래와 같다.That is, by measuring the back pressure of DOC + DPF by the differential pressure sensor 30 immediately after regeneration of the DPF 20 in the absence of soot, the DOC + DPF differential pressure is secured, and the differential pressure of the DPF 20 is determined according to the exhaust flow rate. Also, by securing it, it is possible to calculate the DOC differential pressure. Expressing this as a formula is as follows.

DOC 차압 = DOC + DPF 차압(@0g soot) - DPF 차압(@0g soot)DOC differential pressure = DOC + DPF differential pressure (@0g soot) - DPF differential pressure (@0g soot)

하지만, DOC 전단이 막히게 되면, 위 수식에 의해 계산된 DOC 차압이 도 3의 점선과 같이 DOC 차압모델값(@0g soot) 보다 높은 차압으로 나타나게 됨으로써, 현재 DOC(10) 전단에 막힘이 발생된 것으로 진단할 수 있게 된다.However, when the DOC front end is blocked, the DOC differential pressure calculated by the above formula appears as a higher differential pressure than the DOC differential pressure model value (@0g soot) as shown by the dotted line in FIG. can be diagnosed as

아울러, 본 발명에서는 DOC 차압과 DOC 차압모델값의 차이가 설정값 이상이 되는 경우, DOC(10) 전단의 막힘이 발생한 것으로 진단할 수 있는데, 여기서 상기 설정값은 배기온도 및 배기유량에 따라 결정될 수 있다.In addition, in the present invention, when the difference between the DOC differential pressure and the DOC differential pressure model value is greater than or equal to the set value, it can be diagnosed that the front end of the DOC 10 is clogged, where the set value is determined according to the exhaust temperature and exhaust flow rate. can

즉, 도 4는 본 발명에서 DOC(10) 막힘 정도에 따른 배기유량별 DOC 차압을 나타낸 도면으로, 배기온도 300℃에서 DOC(10) 전단 입구면이 각각 25%, 50%, 100% 개방된 제품의 DOC 차압을 나타내고 있다.That is, FIG. 4 is a view showing the DOC differential pressure for each exhaust flow rate according to the degree of clogging of the DOC 10 in the present invention. At an exhaust temperature of 300° C., the front end inlet of the DOC 10 is 25%, 50%, and 100% open, respectively. It shows the DOC differential pressure of the product.

이에, 도면과 같이 DOC(10) 전단 막힘이 발생할 경우, 고유량일수록 차압이 증가하므로, 설정값이 배기온도 및 배기유량에 따라 달리 결정이 된다.Accordingly, as shown in the figure, when shear clogging occurs in the DOC 10 , the differential pressure increases as the high flow rate increases, so the set value is determined differently depending on the exhaust temperature and the exhaust flow rate.

한편, 도 5는 본 발명에서 DOC(10) 전단의 온도를 상승시키기 위한 후분사 시기를 설명하기 위한 도면이다.On the other hand, Figure 5 is a view for explaining the post-injection time for increasing the temperature of the front end of the DOC (10) in the present invention.

도면을 참조하면, 본 발명에서 상기 제어기(40)는 연료 후분사를 통해 DOC(10) 전단의 배기온도를 상승시킬 수 있다.Referring to the drawings, in the present invention, the controller 40 may increase the exhaust temperature of the front end of the DOC 10 through fuel post-injection.

바람직하게는, DOC(10) 막힘을 용이하게 제거하기 위해 Post_2 후분사를 이용하여 DOC(10) 전단 배기온을 상승시킬 수 있다.Preferably, in order to easily remove the blockage of the DOC 10, the exhaust temperature in front of the DOC 10 may be increased by using the Post_2 post injection.

DOC(10) 배기온을 상승시키는 일례로, DPF(20) 재생 직후에 후분사를 통해 DOC(10) 전단의 배기온을 상승시켜 DOC(10) 전단의 막힘을 제거할 수 있다. 이는, 차량의 정상 주행시에 DOC(10) 전단 막힘을 제거하게 된다.As an example of increasing the exhaust temperature of the DOC 10 , the blockage of the front end of the DOC 10 may be removed by increasing the exhaust temperature of the front end of the DOC 10 through after-injection immediately after the DPF 20 is regenerated. This eliminates the clogging of the front end of the DOC 10 during normal driving of the vehicle.

다른 예로, DPF(20) 재생 후, DOC(10)의 차압을 계산하고, DOC(10)가 막힌 것으로 판단할 경우, 다음 DPF(20) 재생시에 Post_2 후분사량을 증대하여 DOC(10) 막힘을 제거할 수 있다. 이는, DPF(20) 재생시에 DOC(10) 전단 막힘을 제거하게 된다.As another example, after the DPF 20 is regenerated, the differential pressure of the DOC 10 is calculated, and when it is determined that the DOC 10 is clogged, the DOC 10 is blocked by increasing the Post_2 post-injection amount at the next DPF 20 regeneration. can be removed This eliminates the clogging of the front end of the DOC 10 when the DPF 20 is regenerated.

아울러, DOC(10) 전단 배기온도를 상승시키는 다른 방안으로, 상용 배기시스템에 퓨얼 인젝션(Fuel Injection) 시스템이 구성되어 있는 경우, DOC(10) 전단의 Fuel injection을 증대시켜, DOC(10) 전단의 배기온을 상승시킬 수 있다. In addition, as another method of increasing the exhaust temperature in front of the DOC 10, when a fuel injection system is configured in a commercial exhaust system, by increasing the fuel injection in the front end of the DOC 10, the front end of the DOC 10 can increase the exhaust temperature.

그리고, 상기 DOC(10) 전단의 배기온도는 soot의 연소를 위해 요구되는 온도범위로 일정시간 이상 상승시킬 수 있다.In addition, the exhaust temperature of the front end of the DOC 10 may be increased to a temperature range required for soot combustion for a certain period of time or longer.

즉, DOC(10)의 전단 막힘 물질은 접착성이 높은 미연소 연료 및 엔진 오일 성분으로, 이를 제거하기 위해서는 DOC(10) 전단의 배기온을 상승시켜야 한다.That is, the front end clogging material of the DOC 10 is an unburned fuel and engine oil component having high adhesiveness, and in order to remove it, the exhaust temperature of the front end of the DOC 10 must be increased.

도 6은 DOC 전단 배기온도에 따른 DOC 막힘 제거효율을 나타낸 도면으로, 도면과 같이 soot 제거에 효율적인 온도는 475℃ 이상임을 확인할 수 있다.6 is a view showing the DOC clogging removal efficiency according to the exhaust temperature in front of the DOC. As shown in the figure, it can be confirmed that the effective temperature for soot removal is 475° C. or higher.

따라서, DOC(10) 전단이 막힌 경우, DOC(10) 전단 배기온도를 475℃ 이상으로 일정시간 유지함으로써, DOC(10) 전단 막힘 물질을 제거할 수 있다.Accordingly, when the front end of the DOC 10 is blocked, the DOC 10 front end clogging material may be removed by maintaining the exhaust temperature at the front end of the DOC 10 at 475° C. or higher for a certain period of time.

한편, 도 7은 본 발명에서 DOC(10) 막힘을 제거하기 위한 방법을 전체적으로 예시한 플로우차트이다.On the other hand, Figure 7 is a flowchart illustrating the overall method for removing the blockage of the DOC (10) in the present invention.

본 발명에 따른 DOC(10) 막힘 제거방법의 구성을 살펴보면, 제어기(40)가, DOC(10) 전단과 DPF(20) 후단 사이의 차압을 검출하는 차압검출단계; 제어기(40)가, DOC(10) 전단과 DPF(20) 후단 사이의 차압을 기반으로 DOC 차압을 계산하는 DOC차압 계산단계; 및 제어기(40)가, 상기 DOC 차압과 DOC 차압모델값의 차이가 설정값 초과시, DOC(10) 전단의 배기온도를 상승시키도록 제어하는 배기온도 상승단계;를 포함하여 구성이 된다.Looking at the configuration of the method for removing the blockage of the DOC 10 according to the present invention, the controller 40 includes a differential pressure detection step of detecting a differential pressure between the front end of the DOC 10 and the rear end of the DPF 20 ; DOC differential pressure calculation step in which the controller 40 calculates the DOC differential pressure based on the differential pressure between the front end of the DOC 10 and the rear end of the DPF 20; and an exhaust temperature raising step in which the controller 40 controls the exhaust temperature of the front end of the DOC 10 to rise when the difference between the DOC differential pressure and the DOC differential pressure model value exceeds a set value.

이에, 도면을 참조하여, DOC(10) 전단의 막힘이 발생한 것을 진단 및 제거하는 과정을 설명하면, 차량의 주행과정에서 차압센서(30)를 이용하여 DOC + DPF의 차압과, 배기유량을 모니터링한다(S10).Accordingly, referring to the drawings, the process of diagnosing and removing the clogging of the front end of the DOC 10 will be described. The differential pressure of DOC + DPF and the exhaust flow rate are monitored using the differential pressure sensor 30 during the driving process of the vehicle. do (S10).

이어서, DPF(20)의 재생이 진행되어 soot 포집량이 일정값(예, 5g) 미만으로 판단시(S20), 차압센서(30)를 통해 검출되는 DOC + DPF의 차압과, 배기유량 등을 기반으로 DOC 차압을 계산한다(S30).Then, when the regeneration of the DPF 20 proceeds and the soot collection amount is determined to be less than a certain value (eg, 5 g) (S20), based on the differential pressure of DOC + DPF detected through the differential pressure sensor 30 and the exhaust flow rate, etc. to calculate the DOC differential pressure (S30).

이에, 계산된 현재의 DOC 차압과 초기 DOC 차압모델값의 차이가 설정값(b)을 초과하는지 판단한다(S40). 이때에, b값은 배기온도와 배기유량에 따라 맵의 형태로 구성이 된다.Accordingly, it is determined whether the difference between the calculated current DOC differential pressure and the initial DOC differential pressure model value exceeds a set value (b) (S40). At this time, the b value is configured in the form of a map according to the exhaust temperature and the exhaust flow rate.

S40단계의 판단결과, 현재 DOC 차압과 초기 DOC 차압모델값 차이가 설정값(b) 초과시, DOC(10) 전단이 막힌 것으로 진단한다.As a result of the determination in step S40, when the difference between the current DOC differential pressure and the initial DOC differential pressure model value exceeds the set value (b), it is diagnosed that the front end of the DOC 10 is blocked.

이에, DOC(10) 전단의 배기온도를 일정 온도 이상으로 상승시켜, DOC(10) 전단을 막고 있는 연소생성물을 연소 및 제거시키게 된다(50).Accordingly, the exhaust temperature of the front end of the DOC 10 is raised to a certain temperature or more, and combustion products blocking the front end of the DOC 10 are burned and removed (50).

상술한 바와 같이, 본 발명은 DOC + DPF의 차압 변화에 따라 DOC의 막힘을 판단하고, DOC(10)의 막힘이 발생한 것으로 판단한 경우, DOC(10) 전단의 온도를 상승시켜 DOC(10) 전단 막힘을 제거하게 된다.As described above, the present invention determines the clogging of the DOC according to the change in the differential pressure of DOC + DPF, and when it is determined that the clogging of the DOC 10 has occurred, the temperature of the front end of the DOC 10 is raised to the front end of the DOC 10 . will remove the blockage.

따라서, 배기시스템의 간단한 구조 변경을 통해 DOC(10) 전단의 막힘을 진단 및 제거 가능함으로써, DOC(10) 전단의 배압 증가에 따른 연비 및 출력감소를 줄이는 것은 물론, 배기시스템의 고장을 방지하여 배기계 내구성 및 상품성을 향상시키게 된다.Therefore, it is possible to diagnose and remove the blockage at the front end of the DOC 10 through a simple structural change of the exhaust system, thereby reducing fuel efficiency and output decrease due to an increase in back pressure at the front end of the DOC 10, as well as preventing the failure of the exhaust system. It will improve the exhaust system durability and marketability.

한편, 본 발명은 상기한 구체적인 예에 대해서만 상세히 설명되었지만 본 발명의 기술사상 범위 내에서 다양한 변형 및 수정이 가능함은 당업자에게 있어서 명백한 것이며, 이러한 변형 및 수정이 첨부된 특허청구범위에 속함은 당연한 것이다.On the other hand, although the present invention has been described in detail only with respect to the specific examples described above, it is obvious to those skilled in the art that various modifications and variations are possible within the scope of the technical spirit of the present invention, and it is natural that such variations and modifications belong to the appended claims. .

1 : 배기라인
10 : DOC
20 : DPF
30 : 차압센서
32 : 차압파이프
40 : 제어기1: exhaust line
10: DOC
20: DPF
30: differential pressure sensor
32: differential pressure pipe
40: controller

Claims (7)

배기라인을 따라 순차적으로 배치된 DOC 및 DPF;
상기 DOC 전단과 DPF 후단 사이의 차압을 측정하는 차압센서; 및
상기 차압센서에 의해 측정된 차압을 기반으로 계산된 DOC 차압과 DOC 차압모델값의 차이가 설정값 초과시, DOC 전단의 배기온도를 상승시키도록 제어하는 제어기;를 포함하는 배기시스템의 DOC 막힘 제거시스템.DOC and DPF sequentially disposed along the exhaust line;
a differential pressure sensor for measuring the differential pressure between the front end of the DOC and the rear end of the DPF; and
When the difference between the DOC differential pressure calculated based on the differential pressure measured by the differential pressure sensor and the DOC differential pressure model value exceeds a set value, a controller to control the exhaust temperature in front of the DOC to rise; . 청구항 1에 있어서,
상기 DOC 차압과 DOC 차압모델값은 DPF의 재생 직후를 기준으로 계산된 값인 것을 특징으로 하는 배기시스템의 DOC 막힘 제거시스템.The method according to claim 1,
The DOC differential pressure and DOC differential pressure model values are values calculated on the basis of immediately after regeneration of the DPF. 청구항 2에 있어서,
상기 DOC 차압은, DPF 재생 직후에 차압센서에 의해 측정된 차압에서 DPF 재생 직후의 DPF 차압을 감산한 값으로 계산되고;
상기 DPF 차압은, DPF의 재생 직후를 기준으로 배기유량에 따라 결정되는 모델값인 것을 특징으로 하는 배기시스템의 DOC 막힘 제거시스템.3. The method according to claim 2,
the DOC differential pressure is calculated as a value obtained by subtracting the DPF differential pressure immediately after the DPF regeneration from the differential pressure measured by the differential pressure sensor immediately after the DPF regeneration;
The DPF differential pressure is a DOC blockage removal system of an exhaust system, characterized in that it is a model value determined according to an exhaust flow rate immediately after the regeneration of the DPF. 청구항 3에 있어서,
상기 설정값은 배기온도 및 배기유량에 따라 결정되는 것을 특징으로 하는 배기시스템의 DOC 막힘 제거시스템.4. The method according to claim 3,
The DOC blockage removal system of the exhaust system, characterized in that the set value is determined according to the exhaust temperature and the exhaust flow rate. 청구항 1에 있어서,
상기 제어기는 후분사를 통해 DOC 전단의 배기온도를 상승시키는 것을 특징으로 하는 배기시스템의 DOC 막힘 제거시스템.The method according to claim 1,
The DOC blockage removal system of the exhaust system, characterized in that the controller increases the exhaust temperature of the front end of the DOC through the after-injection. 청구항 1에 있어서,
상기 DOC 전단의 배기온도는 soot의 연소를 위해 요구되는 온도범위로 일정시간 이상 상승시키는 것을 특징으로 하는 배기시스템의 DOC 막힘 제거시스템.The method according to claim 1,
The DOC blockage removal system of the exhaust system, characterized in that the exhaust temperature in front of the DOC is raised to a temperature range required for soot combustion for a certain time or longer. 청구항 1에 기재된 배기시스템의 DOC 막힘을 제거하는 방법으로서,
제어기가, DOC 전단과 DPF 후단 사이의 차압을 검출하는 차압검출단계;
제어기가, DOC 전단과 DPF 후단 사이의 차압을 기반으로 DOC 차압을 계산하는 DOC차압 계산단계; 및
제어기가, 상기 DOC 차압과 DOC 차압모델값의 차이가 설정값 초과시, DOC 전단의 배기온도를 상승시키도록 제어하는 배기온도 상승단계;를 포함하는 배기시스템의 DOC 막힘 제거방법.A method of removing the DOC clogging of an exhaust system according to claim 1, comprising:
a differential pressure detection step in which the controller detects a differential pressure between the front end of the DOC and the rear end of the DPF;
a DOC differential pressure calculation step in which the controller calculates the DOC differential pressure based on the differential pressure between the front end of the DOC and the rear end of the DPF; and
and an exhaust temperature raising step of controlling, by a controller, to increase the exhaust temperature in front of the DOC when the difference between the DOC differential pressure and the DOC differential pressure model value exceeds a set value.
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* Cited by examiner, † Cited by third party
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KR101575478B1 (en) 2014-05-27 2015-12-07 현대자동차주식회사 Apparatus and method for exhaust gas recirculation

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