KR100290161B1 - Method for diagnosing trouble in exhaust gas recirculator - Google Patents

Method for diagnosing trouble in exhaust gas recirculator Download PDF

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Publication number
KR100290161B1
KR100290161B1 KR1019960057564A KR19960057564A KR100290161B1 KR 100290161 B1 KR100290161 B1 KR 100290161B1 KR 1019960057564 A KR1019960057564 A KR 1019960057564A KR 19960057564 A KR19960057564 A KR 19960057564A KR 100290161 B1 KR100290161 B1 KR 100290161B1
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South Korea
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egr
oxygen sensor
exhaust gas
egr valve
linear oxygen
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KR1019960057564A
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Korean (ko)
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KR19980038649A (en
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박용정
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이계안
현대자동차주식회사
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
    • F02M26/49—Detecting, diagnosing or indicating an abnormal function of the EGR system
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
    • F02M26/45—Sensors specially adapted for EGR systems
    • F02M26/46—Sensors specially adapted for EGR systems for determining the characteristics of gases, e.g. composition
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D21/00—Controlling engines characterised by their being supplied with non-airborne oxygen or other non-fuel gas
    • F02D21/06—Controlling engines characterised by their being supplied with non-airborne oxygen or other non-fuel gas peculiar to engines having other non-fuel gas added to combustion air
    • F02D21/08—Controlling engines characterised by their being supplied with non-airborne oxygen or other non-fuel gas peculiar to engines having other non-fuel gas added to combustion air the other gas being the exhaust gas of engine
    • F02D2021/083—Controlling engines characterised by their being supplied with non-airborne oxygen or other non-fuel gas peculiar to engines having other non-fuel gas added to combustion air the other gas being the exhaust gas of engine controlling exhaust gas recirculation electronically

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Analytical Chemistry (AREA)
  • Exhaust-Gas Circulating Devices (AREA)

Abstract

PURPOSE: A trouble diagnosing method for an Exhaust Gas Recirculator (EGR) is provided to rapidly judge a trouble in the EGR by detecting signal variations according to EGR amount with a linear oxygen sensor. CONSTITUTION: A trouble diagnosing method has the steps of: (S1) deciding whether EGR control proceeds to a close-loop mode; (S2) operating an EGR valve of an EGR if the EGR control proceeds to the close-loop; (S3) comparing whether a value from a linear oxygen sensor is smaller than a threshold value according to EGR duty; (S4) deciding that the EGR valve is abnormal if the linear oxygen sensor value is smaller than the threshold value according to EGR duty; (S5) comparing the amount of opening a throttle with the threshold value if the linear oxygen sensor value is larger than the threshold value according to EGR duty; (S6) deciding whether the EGR control is an open-loop mode if the throttle opening amount is smaller than the threshold value; and (S7) deciding the EGR valve is normal if the EGR control is not the open-loop mode.

Description

배기가스 재순환장치(E.G.R)의 고장유무 진단방법Diagnosis method of failure of exhaust gas recirculation system (E.G.R)

본 발명은 배기가스 재순환장치(E.G.R)의 고장 유무 진단방법에 관한 것이다.알려진 바와 같이 배기가스 재순환장치는 NOx가 가장 많이 발생되는 이론 혼합비 부근에서 NOx를 저감시키기 위하여 배기가스의 일부를 엔진의 흡입 매니폴드로 재순환시켜 가능한한 출력감소를 최소로 하면서 목적하는 최고연소 온도를 조금 낮추어 NOx를 줄이게 하는 장치다.The present invention relates to a method for diagnosing the failure of an exhaust gas recirculation apparatus (EGR). As is known, the exhaust gas recirculation apparatus sucks a part of the exhaust gas into the engine to reduce the NOx in the vicinity of the theoretical mixing ratio where NOx is most generated. By recycling to the manifold, it is possible to reduce the NOx by slightly lowering the desired maximum combustion temperature while minimizing the power reduction as much as possible.

이와 같은 배기가스 재순환 장치에 있어 이미 연소된 배기가스는 신선한 산소가 당연히 없으므로 연소실내에 유입되면 연소반응에 좋은 영향을 주지 못한다.In such an exhaust gas recirculation apparatus, the exhaust gas already burned does not have fresh oxygen, and thus does not have a good effect on the combustion reaction when introduced into the combustion chamber.

즉, 엔진 상태가 불안정한 공전시나 엔진 웜업전에서는 EGR밸브가 작동하지 않고 그 이외에는 스로틀 밸브가 열림에 따라 흡입 다기관의 진공도에 의해 EGR밸브가 서서히 열리면서 배기가스가 흡입 매니폴드로 유입되게 된다.That is, the engine is unstable and the EGR valve does not operate before engine warm-up. Otherwise, as the throttle valve opens, the EGR valve is gradually opened by the vacuum degree of the intake manifold, and the exhaust gas flows into the intake manifold.

이와 같은 배기가스 재순환 장치에 있어서, 종래 배기가스 재순환 장치의 고장유무를 판단함에 있어서는 2가지의 방식을 채택하여 진단하고 있다.In such an exhaust gas recirculation apparatus, two methods have been adopted to diagnose whether or not there is a failure of the exhaust gas recirculation apparatus.

즉, 멥센서(Manifold Absolute Pressure Sensor : MAP센서)를 이용한 EGR진단 방식과 온도센서를 이용한 EGR진단 방식이 있다.In other words, there is an EGR diagnosis method using a fold sensor (Manifold Absolute Pressure Sensor: MAP sensor) and an EGR diagnosis method using a temperature sensor.

전자인 멥센서를 이용한 방식은 연료 공급차단 조건하에서 EGR밸브를 강제구동케하여 부압변동량을 감지케 함으로써 배기가스 재순환장치의 오작동을 감지하도록 하는 것이고, 후자인 온도센서를 이용한 방식은 EGR밸브의 바깥(out let )측에 온도센서를 장착하여 EGR밸브 작동시 온도를 감지하여 배기가스 재순환 장치의 오작동을 감지하는 것이다.The method using the electronic shock sensor detects a malfunction of the exhaust gas recirculation system by forcibly driving the EGR valve under the fuel supply shutoff condition to detect the negative pressure fluctuation, and the latter method uses the temperature sensor outside of the EGR valve. It is to detect the malfunction of the exhaust gas recirculation device by detecting the temperature when the EGR valve is operated by installing the temperature sensor on the (out let) side.

이와 같은 멥센서 이용방식은 흡기 매니폴드의 부압을 전기로 검출하여 엔진에 흡입되는 공기량을 측정하는 것이어서, 전기저항의 변화에 매우 민감해야 하는 점과 EGR밸브의 강제구동에 따른 부압 변동량을 정확하게 검지할 수 없는 문제점이 지적되고, 후자인 온도센서 이용방식은 EGR밸브를 통하는 배기가스 온도를 감지하는 것이어서 그 응답처리 시간이 늦는 등의 문제점이 지적된다.In this method, the sensor detects the negative pressure of the intake manifold with electricity and measures the amount of air sucked into the engine.It must be very sensitive to the change in electrical resistance and accurately detects the negative pressure fluctuation caused by the forced operation of the EGR valve. A problem that cannot be pointed out is pointed out, and the latter method of using a temperature sensor is to sense an exhaust gas temperature through an EGR valve, and thus a problem such as a slow response time is pointed out.

본 발명은 상기와 같은 종래 배기가스 재순환장치의 오작동 감지 방식에 의한 문제점을 해소하기 위하여 창출한 것으로 리니어 산소 센서(Linear O2센서)를 이용하여 EGR량에 따른 신호변화를 감지하여 배기가스 재순환장치의 오작동 여부를 판단토록 함으로써 일반적인 클로즈-루프(Close-loop)조건하에서 오작동 여부의 모니터링을 용이하게 행할 수 있는 목적과 응답처리시간의 단축을 기하여 배기가스 재순환장치의 오작동 여부 판단을 빠른 시간내에 판단할 수 있는 목적을 가진다.The present invention was created in order to solve the problem caused by the malfunction detection method of the conventional exhaust gas recirculation device as described above by using a linear oxygen sensor (Linear O 2 sensor) to detect the signal change according to the amount of EGR exhaust gas recirculation device In order to determine the malfunction of the exhaust gas recirculation device in a short time, it is possible to easily monitor the malfunction under normal close-loop conditions and to shorten the response processing time. It has a purpose to do it.

상기한 과제를 달성하기 위한 본 발명은 클로즈-루프로 진입한 상태에서 EGR 밸브를 작동시켜 리니어 산소센서 출력값이 EGR듀티에 따른 드레쉬 홀드값보다 적으면 배기가스 재순한 장치가 오작동하고 있음으로 판단하고, 리니어 산소 센서 출력 값이 EGR듀티에 따른 드레쉬홀드 값보다 크면 스로틀 개도량과 드레쉬 홀드값을 비교케하여 스로틀 개도량이 드레쉬 홀드값보다 적게 되면 오픈-루프(open-loop)인지를 판단케하고, 오픈-루프 제어 모드가 아니면 EGR밸브는 정상으로 판단토록함을 특징으로 한다.According to the present invention for achieving the above object, if the linear oxygen sensor output value is less than the threshold hold value according to the EGR duty by operating the EGR valve in the closed-loop state, it is determined that the exhaust gas recycling device is malfunctioning. If the output value of the linear oxygen sensor is greater than the threshold value according to the EGR duty, the throttle opening amount and the threshold hold value can be compared to determine whether the throttle opening amount is less than the threshold hold value. In the case of the open-loop control mode, the EGR valve is judged to be normal.

도 1은 본 발명을 설명하기 위한 플로우 차트1 is a flow chart for explaining the present invention

도 2는 일반 산소 센서 출력 특성과 리니어 산소 센서 출력 특성도2 is a general oxygen sensor output characteristics and linear oxygen sensor output characteristics

실공기/연료비Actual air / fuel costs

본 발명은 도 2에 도시한 바와 같이 λ =1 ( λ =--- ------------- )을 출력하는, 특성을 가진 리니어According to the present invention, a linear having the characteristics of outputting λ = 1 (λ = --- -------------) as shown in FIG.

이론공기/연료비Theoretical Air / Fuel Cost

산소센서를 이용한 모니터링으로 EGR량에 따른 신호변화를 감지하여 EGR밸브의 오동작 여부를 판단토록 하는 것이다.By monitoring with oxygen sensor, it detects the signal change according to the amount of EGR and judges whether the EGR valve is malfunctioning.

EGR밸브의 제어는 ECU(Electronic control unit)에 의해 구현되는데, ECU의 제어모드는 크게 클로즈-루프(보정치 적용모드)와 오픈-루프(보정치 비적용모드)로 나뉘어진다.The control of the EGR valve is implemented by an electronic control unit (ECU). The control mode of the ECU is largely divided into a closed-loop (adjustment value application mode) and an open-loop (no correction value application mode).

상기 클로즈-루프는 보정치 적용모드를 말하는데 산소센서의 감지값을 미리 설정한 드레쉬 홀드값(기준값)과 비교하여 그 차이에 따라 보정치를 산정하여 EGR 밸브의 개도량을 피드백 제어하는 제어모드이며, 오픈-루프는 보정치 비적용모드를 말하는데 산소센서의 감지값에 따라 그때 그때 EGR밸브의 개도량을 제어하는 제어모드를 말한다.The closed-loop refers to a correction value application mode. The closed-loop is a control mode that compares a detected value of an oxygen sensor with a preset threshold hold value (reference value) and calculates a correction value according to the difference to feedback control the opening amount of the EGR valve. The open-loop refers to the non-correction mode, which is a control mode that controls the opening amount of the EGR valve at that time in accordance with the detection value of the oxygen sensor.

도 1 은 본 발명인 배기가스 재순환장치의 오동작 여부판단을 위한 플로우차트이다.Figure 1 is a flow chart for determining whether the malfunction of the exhaust gas recirculation apparatus of the present invention.

본 발명은 EGR제어가 클로즈-루프로 진입했는지의 여부를 판단하는 단계(S1)와, 상기 단계(S1)에서 클로즈-루프 제어 모드로 진입되면 배기가스 순환장치의 EGR밸브를 작동시키는 단계(S2)와, 상기 단계(S2)에서 리니어 산소 센서 출력값＜EGR호 듀티에 따른 드레쉬 홀드값을 비교하는 단계(S5)와, 상기 단계(S3)에서 리니어 산소센서 출력값<EGR듀티에 따른 드레쉬 홀드값이면 EGR밸브가 비정상임을 판단하는 단계(S4)와, 상기 단계(S3)에서 리니어 산소센서 출력값>EGR듀티에 다른 드레쉬 홀드값이면 스로틀 개도량과 드레쉬 홀드값과를 비교케 하는 단계(S5)와 상기 단계(S5)에서 스로틀 개도량 < 드레쉬 홀드값이면 오픈-루프 제어 인지를 판단케하는 단계(S6)와, 상기 단계(S6)에서 오픈-루프 제어 모드가 아니면 EGR밸브가 정상임을 판단하는 단계(S7)와로 이루어진다.The present invention is to determine whether or not the EGR control has entered the closed-loop (S 1 ), and operating the EGR valve of the exhaust gas circulation device when entering the closed-loop control mode in the step (S 1 ) (S 2) and the step (S 2) the linear oxygen sensor output value <comparing drain Threshold value (S 5) and the step (S 3) a linear oxygen sensor output in accordance with the EGR call duty in <EGR If it is a threshold hold value according to the duty, it is determined that the EGR valve is abnormal (S 4 ), and if the threshold hold value is different from the linear oxygen sensor output value> EGR duty in step S 3 , the throttle opening amount and the threshold hold are determined. comprising: Kane comparing the value (S 5) and the step (S 5) throttle one metrology <drain Threshold value is opened in the steps of Ke determine if the loop control (S 6) and the step (S 6) If it is not the open-loop control mode in the step of determining that the EGR valve is normal (S7) It consists of.

상기에 있어서, 리니어 산소센서 출력 = 스로틀 밸브 개도후의 리니어 산소센서 출력-스로틀 밸브 개도전의 리니어 산소 센서 출력이다.In the above, the linear oxygen sensor output = linear oxygen sensor output after opening the throttle valve-the linear oxygen sensor output before opening the throttle valve.

이와 같은 본 발명은 EGR밸브 작동시 혼합기에 공기대신 일정량 만큼 배기가스가 흡입되므로 혼합기는 농후(Rich)해진다. 이것은 리니어 산소 센서 출력에 변화를 가져오게 되고, 이때 예측될 수 있는 산소 센서 출력 변화가 감지되면 EGR 밸브는 정상으로 판정하게 하며, 산소센서 출력 변화가 없으면 EGR 밸브에 이상이 발생된 것으로 이때에는 EGR밸브는 고장으로 판정하게 하는 것이다. 따라서 본 발명은 일반적인 클로즈-루프 조건하에서도 EGR밸브의 오작동 여부를 판단처리할 수 있게 되고, 리니어 산소 센서에 의한 응답 처리시간이 크게 단축되게 된다.In the present invention, since the exhaust gas is sucked by a predetermined amount instead of air during the operation of the EGR valve, the mixer becomes rich. This causes a change in the output of the linear oxygen sensor. At this time, if a predictable change in the oxygen sensor output is detected, the EGR valve is determined to be normal. If there is no change in the oxygen sensor output, an error occurs in the EGR valve. The valve is to be judged to be a failure. Therefore, the present invention can determine whether or not the EGR valve is malfunctioning even under a general closed-loop condition, and the response processing time by the linear oxygen sensor is greatly shortened.

이상과 같이 본 발명은 직선성을 갖는 리니어 산소 센서를 이용하여 EGR 밸브 작동시 리니어 산소 센서 출력 변화를 감지하여 EGR밸브의 오작동 여부를 판단토록 하는 것으로 종래 멥센서 및 온도센서를 이용한 배기가스 재순환장치의 오작동 판단 방식보다 EGR밸브의 오작동 판단 유무가 매우 정확하게 이루어질 뿐 아니라 보다 빠른 시간이내에 EGR밸브의 오작동 유무를 확인할 수 있어 EGR밸브 고장에 따른 NOx증가를 미연에 방지할 수 있고, 일반적인 클로즈-루프 조건하에서도 EGR밸브의 오작동 여부를 판단처리할 수 있어 그 판단처리가 매우 수월한 효과를 가진다.As described above, the present invention uses a linear oxygen sensor having linearity to detect a change in the output of the linear oxygen sensor when the EGR valve is operated to determine whether the EGR valve is malfunctioning. It is possible to check whether the EGR valve is malfunctioned more accurately than the method of determining the malfunction of the EGR valve, and also to check the malfunction of the EGR valve within a shorter time, thereby preventing the increase of NOx due to the failure of the EGR valve. Under such circumstances, it is possible to judge whether or not the malfunction of the EGR valve is performed, and thus the judgment processing has a very easy effect.

Claims (1)

클로즈-루프로 진입했는지의 여부를 판단하는 단계(S1)와, 상기 단계(S1)에서 클로즈-루프 제어 모드로 진입되면 배기가스 순환장치의 EGR 밸브를 작동시키는 단계(S2)와, 상기 단계(S2)에서 리니어 산소 센서 출력값과 EGR듀티에 따른 드레쉬 홀드값을 비교하는 단계(S3)와, 상기 단계(S3)에서 리니어 산소 센서 출력값<EGR듀티에 따른 드레쉬 홀드값이면 EGR밸브가 비정상임을 판단하는 단계(S3)와, 상기 단계(S3)에서 리니어 산소센서 출력값>EGR듀티에 다른 드레쉬 홀드값이면 스로틀 개도량과 드레쉬 홀드값과를 비교케 하는 단계(S5)와, 상기 단계(S5)에서 스로틀 개도량 < 드레쉬 홀드값이면 오픈-루프 제어 인지를 판단케하는 단계(S6)와, 상기 단계(S6)에서 오픈-루프 제어 모드가 아니면 EGR밸브가 정상임을 판단하는 단계(S7)와로 이루어짐을 특징으로 하는 배기가스 재순환장치(E.G.R)의 고장유무 진단방법.Closed-step of determining whether or not the entry into the loop (S 1) and, in said step (S 1) closed - step (S 2) that when entering the loop, the control mode operating the EGR valve of the exhaust gas circulation device and, comparing the drain Threshold value in accordance with a linear oxygen sensor output value and the EGR duty in the step (S 2) (S 3) and the step (S 3) from the linear oxygen sensor output value <drain Threshold value corresponding to the EGR duty If it is determined that the EGR valve is abnormal (S 3 ), and in the step (S 3 ), if the linear oxygen sensor output value> EGR duty is a different dress hold value, the throttle opening amount and the dress hold value are compared. comprising: Ke determine if the loop control (S 6) and open at the step (S 6) - - loop control mode (S 5) and the step (S 5) throttle one metrology <drain sh is the hold value opened from or the step of determining that the EGR valve is normal (S 7) the particular yirueojim waro Fault diagnosis of whether or not exhaust gas recirculation (EGR) as set.
KR1019960057564A 1996-11-26 1996-11-26 Method for diagnosing trouble in exhaust gas recirculator KR100290161B1 (en)

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