JP2011017325A - Device for determining failure of exhaust system of internal combustion engine - Google Patents

Device for determining failure of exhaust system of internal combustion engine Download PDF

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JP2011017325A
JP2011017325A JP2009163971A JP2009163971A JP2011017325A JP 2011017325 A JP2011017325 A JP 2011017325A JP 2009163971 A JP2009163971 A JP 2009163971A JP 2009163971 A JP2009163971 A JP 2009163971A JP 2011017325 A JP2011017325 A JP 2011017325A
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exhaust
failure
exhaust gas
temperature
nozzle vane
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JP5326887B2 (en
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Akinori Morishima
彰紀 森島
Kenichi Tsujimoto
健一 辻本
Mikio Inoue
三樹男 井上
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Toyota Motor Corp
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/22—Safety or indicating devices for abnormal conditions
    • F02D41/221—Safety or indicating devices for abnormal conditions relating to the failure of actuators or electrically driven elements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/0002—Controlling intake air
    • F02D41/0007—Controlling intake air for control of turbo-charged or super-charged engines
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B37/00—Engines characterised by provision of pumps driven at least for part of the time by exhaust
    • F02B37/12—Control of the pumps
    • F02B37/18—Control of the pumps by bypassing exhaust from the inlet to the outlet of turbine or to the atmosphere
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B37/00—Engines characterised by provision of pumps driven at least for part of the time by exhaust
    • F02B37/12—Control of the pumps
    • F02B37/24—Control of the pumps by using pumps or turbines with adjustable guide vanes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B39/00—Component parts, details, or accessories relating to, driven charging or scavenging pumps, not provided for in groups F02B33/00 - F02B37/00
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/04—Engine intake system parameters
    • F02D2200/0406—Intake manifold pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/14—Introducing closed-loop corrections
    • F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
    • F02D41/1444—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases
    • F02D41/1446—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being exhaust temperatures
    • 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
    • Y02T10/12—Improving ICE efficiencies
    • 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)
  • Supercharger (AREA)

Abstract

PROBLEM TO BE SOLVED: To discriminate the failure of the nozzle vane of a turbine from the failure of an exhaust bypass valve for failure determination.SOLUTION: The turbine of a supercharger is provided with a nozzle vane, and an exhaust bypass valve is provided in a bypass passage formed such that exhaust gas bypasses the turbine wheel of the turbine to flow. The failure of the nozzle vane and the failure of the exhaust bypass valve are discriminated from each other for failure determination based on a temperature and supercharging pressure of the exhaust gas produced after an exhaust gas ejected from the turbine has joined an exhaust gas which has passed the bypass passage.

Description

本発明は、タービンのノズルベーン及び排気バイパス弁の故障を判定する内燃機関の排気系の故障判定装置に関する。   The present invention relates to a failure determination device for an exhaust system of an internal combustion engine that determines a failure of a nozzle vane and an exhaust bypass valve of a turbine.

特許文献１には、過給機付き内燃機関におけるウェストゲートバルブの故障検出のための技術が開示されている。特許文献１では、過給期間における過給圧の上昇度合いを表す過給圧上昇指標値を取得する。そして、過給圧上昇指標値が、基準値以上であればウェストゲートバルブは正常であると判別され、基準値未満であればウェストゲートバルブに閉じ不良が発生していると判別される。   Patent Document 1 discloses a technique for detecting a failure of a wastegate valve in an internal combustion engine with a supercharger. In Patent Literature 1, a supercharging pressure increase index value indicating the degree of increase in supercharging pressure during the supercharging period is acquired. If the supercharging pressure increase index value is equal to or greater than the reference value, it is determined that the wastegate valve is normal, and if it is less than the reference value, it is determined that a closed failure has occurred in the wastegate valve.

特開２００８−０９５５８７号公報JP 2008-095587 A 特開２００９−０５２４０８号公報JP 2009-052408 A 特開平４−１６４１２５号公報JP-A-4-164125 特開２０００−３２９８４９号公報JP 2000-329849 A

内燃機関の排気通路に過給機のタービンが設けられている場合、該タービンのタービンホイールをバイパスして排気が流れるように形成されたバイパス通路が設けられる場合がある。このとき、バイパス通路には、該バイパス通路を流れる排気の流量を調整する排気バイパス弁が設けられる。ウェストゲートバルブは、このような排気バイパス弁の一例である。また、過給機のタービンには、過給圧制御するために、タービンホイールに吹き付けられる排気の流速を可変とするノズルベーンが設けられる場合がある。   When the turbine of the supercharger is provided in the exhaust passage of the internal combustion engine, a bypass passage formed so that the exhaust flows by bypassing the turbine wheel of the turbine may be provided. At this time, the bypass passage is provided with an exhaust bypass valve for adjusting the flow rate of the exhaust gas flowing through the bypass passage. The wastegate valve is an example of such an exhaust bypass valve. In addition, in order to control the supercharging pressure, the turbine of the supercharger may be provided with a nozzle vane that makes the flow rate of the exhaust blown to the turbine wheel variable.

上記のようなノズルベーン及び排気バイパス弁が排気系に設けられている場合、これらが故障し、その開度が正常時とは異なったものとなると、排気エミッションやドライバビリティの悪化を招く虞がある。このような不具合を解消するためには、ノズルベーン又は排気バイパス弁の故障が発生した場合、それを正確に把握することが重要である。   When the nozzle vane and the exhaust bypass valve as described above are provided in the exhaust system, if they break down and the opening degree is different from the normal one, exhaust emission and drivability may be deteriorated. . In order to solve such a problem, it is important to accurately grasp when a failure of the nozzle vane or the exhaust bypass valve occurs.

ここで、排気の背圧に基づいてこれらの故障判定を行なうことが考えられる。しかしながら、ノズルベーン又は排気バイパス弁のいずれが故障しても排気の背圧は変化する。そのため、排気の背圧に基づく故障判定では、ノズルベーンの故障と排気バイパス弁の故障との区別が困難である。   Here, it is conceivable to make these failure determinations based on the exhaust back pressure. However, even if either the nozzle vane or the exhaust bypass valve fails, the exhaust back pressure changes. Therefore, in the failure determination based on the exhaust back pressure, it is difficult to distinguish between the failure of the nozzle vane and the failure of the exhaust bypass valve.

本発明は、上記問題に鑑みてなされたものであって、ノズルベーンの故障と排気バイパス弁の故障とを区別して故障判定を行うことが可能な技術を提供することを目的とする。   The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique capable of making a failure determination by distinguishing between a nozzle vane failure and an exhaust bypass valve failure.

本発明は、タービンから排出された排気の温度とバイパス通路を通過した排気の温度とが異なること、及び、ノズルベーンの開度又は排気バイパス弁の開度が変化すると過給圧が変化することを利用して、ノズルベーンの故障と排気バイパス弁の故障とを区別して故障判定を行なうものである。   The present invention confirms that the temperature of the exhaust gas discharged from the turbine and the temperature of the exhaust gas that has passed through the bypass passage are different, and that the supercharging pressure changes when the opening degree of the nozzle vane or the exhaust bypass valve changes. Utilizing this, the failure determination is performed by distinguishing between the failure of the nozzle vane and the failure of the exhaust bypass valve.

より詳しくは、本発明に係る内燃機関の排気系の故障判定装置は、
内燃機関の排気通路に設けられており、ノズルベーンを有する過給機のタービンと、
該タービンのタービンホイールをバイパスして排気が流れるように形成されたバイパス通路と、
該バイパス通路に設けられ該バイパス通路を流れる排気の流量を調整する排気バイパス弁と、を有する内燃機関の排気系の故障判定装置であって、
前記タービンから排出された排気と前記バイパス通路を通過した排気とが合流した後の排気の温度を検出する排気温度検出手段と、
過給圧を検出する過給圧検出手段と、
前記排気温度検出手段によって検出された排気の温度及び前記過給圧検出手段によって検出された過給圧に基づいて、前記ノズルベーンの故障と前記排気バイパス弁の故障とを区別して判定する故障判定手段と、
を備えたことを特徴とする。 More specifically, the failure determination device for an exhaust system of an internal combustion engine according to the present invention is
A turbocharger turbine provided in an exhaust passage of the internal combustion engine, having a nozzle vane;
A bypass passage formed so that exhaust flows by bypassing the turbine wheel of the turbine;
A failure determination device for an exhaust system of an internal combustion engine, comprising: an exhaust bypass valve provided in the bypass passage and configured to adjust a flow rate of exhaust gas flowing through the bypass passage;
Exhaust temperature detection means for detecting the temperature of the exhaust after the exhaust discharged from the turbine and the exhaust that has passed through the bypass passage merged;
A supercharging pressure detecting means for detecting a supercharging pressure;
A failure determination unit that distinguishes between a failure of the nozzle vane and a failure of the exhaust bypass valve based on the temperature of the exhaust detected by the exhaust temperature detection unit and the boost pressure detected by the boost pressure detection unit. When,
It is provided with.

タービンから排出された排気（以下、タービン側排気と称する）は、タービンホイールの回転に寄与することで、その温度が低下している。そのため、タービン側排気の温度はバイパス通路を通過した排気（以下、バイパス側排気と称する）の温度に比べて低い。両排気間にこのような温度差があることから、ノズルベーン又は排気バイパス弁が故障することで両排気の流量の割合が正常時とは異なるものとなると、タービン側排気とバイパス側排気とが合流した後の排気（以下、合流排気と称する）の温度も正常時とは異なったものとなる。   Exhaust gas discharged from the turbine (hereinafter referred to as turbine-side exhaust gas) contributes to the rotation of the turbine wheel, and thus its temperature is lowered. Therefore, the temperature of the turbine-side exhaust is lower than the temperature of the exhaust that has passed through the bypass passage (hereinafter referred to as bypass-side exhaust). Since there is such a temperature difference between the two exhausts, if the nozzle vane or the exhaust bypass valve breaks down and the ratio of the flow rates of the two exhausts differs from the normal state, the turbine side exhaust and the bypass side exhaust will merge. The temperature of the exhaust gas after this (hereinafter referred to as merged exhaust gas) is also different from that at normal time.

しかしながら、ノズルベーンの開弁側故障（開度が正常時よりも大きい状態となる故障）が生じたときと、排気バイパス弁の閉弁側故障（開度が正常時よりも小さい状態となる故障）が生じたときとでは、いずれの場合もタービン側排気の流量の割合が増加しバイパス側排気の流量の割合が減少するため、合流排気の温度挙動も同一方向（温度低下）となる。また、ノズルベーンの閉弁側故障が生じたときと、排気バイパス弁の開弁側故障が生じたときとでも、いずれの場合もタービン側排気の流量の割合が減少しバイパス側排気の流量の割合が増加するため、合流排気の温度挙動は同一方向（温度上昇）となる。そのため、合流排気の温度挙動のみでは、ノズルベーンの故障と排気バイパス弁の故障とを区別して判定することは困難である。   However, when a nozzle vane valve-opening failure occurs (failure in which the opening is larger than normal), and an exhaust bypass valve closing failure (failure in which the opening is smaller than normal) In any case, since the ratio of the flow rate of the turbine side exhaust increases and the ratio of the flow rate of the bypass side exhaust decreases, the temperature behavior of the combined exhaust gas is also in the same direction (temperature decrease). Also, in both cases, when the nozzle vane valve closing side failure occurs and when the exhaust bypass valve opening side failure occurs, the turbine-side exhaust flow rate ratio decreases and the bypass-side exhaust flow rate ratio Therefore, the temperature behavior of the combined exhaust gas is in the same direction (temperature rise). Therefore, it is difficult to distinguish and determine the failure of the nozzle vane and the failure of the exhaust bypass valve only by the temperature behavior of the combined exhaust.

一方、ノズルベーン又は排気バイパス弁が故障すると、タービンホイールに吹き付けられる排気の流速が正常時とは異なったものとなるため、過給圧も正常時とは異なったものとなる。   On the other hand, when the nozzle vane or the exhaust bypass valve breaks down, the flow rate of the exhaust gas blown to the turbine wheel is different from that in the normal state, so that the supercharging pressure is also different from that in the normal state.

しかしながら、ノズルベーンの開弁側故障が生じたときと、排気バイパス弁の開弁側故障が生じたときとでは、いずれの場合もタービンホイールに吹き付けられる排気の流速が低下するため、過給圧の挙動も同一方向（過給圧低下）となる。また、ノズルベーンの閉弁側故障が生じたときと、排気バイパス弁の閉弁側故障が生じたときとでも、いずれの場合もタービンホイールに吹き付けられる排気の流速が上昇するため、過給圧の挙動は同一方向（過給圧上昇）となる。そのため、過給圧の挙動のみでも、ノズルベーンの故障と排気バイパス弁の故障とを区別して判定することは困難である。   However, in both cases, when the valve opening side failure of the nozzle vane occurs and when the valve opening side failure of the exhaust bypass valve occurs, the flow rate of the exhaust gas blown to the turbine wheel decreases. The behavior is also in the same direction (supercharging pressure drop). In addition, in both cases, when the nozzle vane closing side failure occurs and when the exhaust bypass valve closing side failure occurs, the flow rate of the exhaust blown to the turbine wheel increases. The behavior is the same direction (supercharging pressure rise). Therefore, it is difficult to distinguish and determine the nozzle vane failure and the exhaust bypass valve failure only by the supercharging pressure behavior alone.

そこで、本発明では、合流排気の温度及び過給圧の両方に基づいて故障判定を行なう。これにより、ノズルベーンの故障と排気バイパス弁の故障とを区別して判定することが可能となる。   Therefore, in the present invention, the failure determination is performed based on both the temperature of the combined exhaust gas and the supercharging pressure. Thereby, it becomes possible to distinguish and determine the failure of the nozzle vane and the failure of the exhaust bypass valve.

本発明においては、ノズルベーンの開度の指令値及び排気バイパス弁の開度の指令値に基づいて、合流排気の温度の基準値である基準排気温度を算出する基準排気温度算出手段と、ノズルベーンの開度の指令値及び排気バイパス弁の開度の指令値に基づいて、過給圧
の基準値である基準過給圧を算出する基準過給圧算出手段と、を更に備えてもよい。 In the present invention, based on the command value for the opening degree of the nozzle vane and the command value for the opening degree of the exhaust bypass valve, reference exhaust temperature calculation means for calculating a reference exhaust temperature that is a reference value of the temperature of the combined exhaust, Reference boost pressure calculating means for calculating a reference boost pressure that is a reference value of the boost pressure based on the command value of the opening and the command value of the opening of the exhaust bypass valve may be further provided.

ここで、基準排気温度とは、ノズルベーンの開度及び排気バイパス弁の開度がこれらの指令値の通りとなったとき、即ち正常時の合流排気の温度のことある。また、基準過給圧とは、ノズルベーンの開度及び排気バイパス弁の開度がこれらの指令値の通りとなったとき、即ち正常時の過給圧のことである。ノズルベーンの開度及び排気バイパス弁の開度と基準排気温度との関係、及び、ノズルベーンの開度及び排気バイパス弁の開度と基準過給圧との関係は実験等に基づいて予め求めることができる。   Here, the reference exhaust temperature refers to the temperature of the combined exhaust gas when the opening degree of the nozzle vane and the opening degree of the exhaust bypass valve are in accordance with these command values, that is, normal. The reference supercharging pressure is the supercharging pressure when the nozzle vane opening and the exhaust bypass valve opening are in accordance with these command values, that is, normal. The relationship between the opening degree of the nozzle vane and the opening degree of the exhaust bypass valve and the reference exhaust temperature, and the relationship between the opening degree of the nozzle vane and the opening degree of the exhaust bypass valve and the reference supercharging pressure can be obtained in advance based on experiments or the like. it can.

そして、上記の場合、故障判定手段は、排気温度検出手段によって検出された合流排気の温度と基準排気温度とを比較すると共に、過給圧検出手段によって検出された過給圧と基準過給圧とを比較することで、ノズルベーンの故障と排気バイパス弁の故障とを区別して判定してもよい。   In the above case, the failure determination means compares the combined exhaust temperature detected by the exhaust temperature detection means with the reference exhaust temperature, and the boost pressure detected by the boost pressure detection means and the reference boost pressure. By comparing these, the nozzle vane failure and the exhaust bypass valve failure may be distinguished and determined.

具体的には、排気温度検出手段によって検出された合流排気の温度が基準排気温度より高く、且つ、過給圧検出手段によって検出された過給圧が基準過給圧より高いときは、ノズルベーンの閉弁側故障が生じていると判定する。また、排気温度検出手段によって検出された合流排気の温度が基準排気温度より高く、且つ、過給圧検出手段によって検出された過給圧が基準過給圧より低いときは、排気バイパス弁の開弁側故障が生じていると判定する。   Specifically, when the temperature of the combined exhaust gas detected by the exhaust gas temperature detection means is higher than the reference exhaust gas temperature and the boost pressure detected by the boost pressure detection means is higher than the reference boost pressure, the nozzle vane It is determined that a failure on the valve closing side has occurred. Further, when the temperature of the combined exhaust detected by the exhaust temperature detecting means is higher than the reference exhaust temperature and the boost pressure detected by the boost pressure detecting means is lower than the reference boost pressure, the exhaust bypass valve is opened. It is determined that a valve side failure has occurred.

また、排気温度検出手段によって検出された合流排気の温度が基準排気温度より低く、且つ、過給圧検出手段によって検出された過給圧が基準過給圧より高いときは、排気バイパス弁の閉弁側故障が生じていると判定する。また、排気温度検出手段によって検出された合流排気の温度が基準排気温度より低く、且つ、過給圧検出手段によって検出された過給圧が基準過給圧より低いときは、ノズルベーンの開弁側故障が生じていると判定する。   Further, when the temperature of the combined exhaust detected by the exhaust temperature detecting means is lower than the reference exhaust temperature and the boost pressure detected by the boost pressure detecting means is higher than the reference boost pressure, the exhaust bypass valve is closed. It is determined that a valve side failure has occurred. Further, when the temperature of the combined exhaust detected by the exhaust temperature detecting means is lower than the reference exhaust temperature and the boost pressure detected by the boost pressure detecting means is lower than the reference boost pressure, the nozzle vane is opened It is determined that a failure has occurred.

本発明によれば、ノズルベーンの故障と排気バイパス弁の故障とを区別して故障判定を行うことができる。   According to the present invention, the failure determination can be performed by distinguishing between the failure of the nozzle vane and the failure of the exhaust bypass valve.

実施例に係る内燃機関およびその吸排気系の概略構成を示す図である。It is a figure which shows schematic structure of the internal combustion engine which concerns on an Example, and its intake / exhaust system. 実施例に係るノズルベーン及びＷＧＶの故障判定のフローを示すフローチャートである。It is a flowchart which shows the flow of a failure determination of the nozzle vane and WGV which concerns on an Example.

以下、本発明の具体的な実施形態について図面に基づいて説明する。本実施例に記載されている構成部品の寸法、材質、形状、その相対配置等は、特に記載がない限りは発明の技術的範囲をそれらのみに限定する趣旨のものではない。   Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. The dimensions, materials, shapes, relative arrangements, and the like of the components described in the present embodiment are not intended to limit the technical scope of the invention to those unless otherwise specified.

＜実施例＞
（内燃機関およびその吸排気系の概略構成）
図１は、本実施例に係る内燃機関およびその吸排気系の概略構成を示す図である。内燃機関１は４つの気筒２を有する車両駆動用のディーゼルエンジンである。各気筒２には該気筒２内に燃料を直接噴射する燃料噴射弁３が設けられている。 <Example>
(Schematic configuration of internal combustion engine and its intake and exhaust system)
FIG. 1 is a diagram showing a schematic configuration of an internal combustion engine and its intake / exhaust system according to the present embodiment. The internal combustion engine 1 is a diesel engine for driving a vehicle having four cylinders 2. Each cylinder 2 is provided with a fuel injection valve 3 that directly injects fuel into the cylinder 2.

内燃機関１には、インテークマニホールド５およびエキゾーストマニホールド７が接続されている。インテークマニホールド５には吸気通路４の一端が接続されている。エキゾーストマニホールド７には排気通路６の一端が接続されている。   An intake manifold 5 and an exhaust manifold 7 are connected to the internal combustion engine 1. One end of an intake passage 4 is connected to the intake manifold 5. One end of an exhaust passage 6 is connected to the exhaust manifold 7.

吸気通路４にはターボチャージャ８のコンプレッサ８ａが設置されている。排気通路６にはターボチャージャ８のタービン８ｂが設置されている。吸気通路４におけるコンプレッサ８ａよりも上流側にはエアフローメータ１１が設けられている。吸気通路４におけるコンプレッサ８ａよりも下流側にはスロットル弁１２が設けられている。   A compressor 8 a of a turbocharger 8 is installed in the intake passage 4. A turbine 8 b of a turbocharger 8 is installed in the exhaust passage 6. An air flow meter 11 is provided upstream of the compressor 8 a in the intake passage 4. A throttle valve 12 is provided in the intake passage 4 downstream of the compressor 8a.

タービン８ｂにはノズルベーン９が設けられている。ノズルベーン９の開度が変更されることで、タービンホイールに吹きつけられる排気の流速が変化し、それによって、ターボ出力が変化する。つまり、本実施例に係るターボチャージャ８は、ノズルベーン９の開度を変更することで過給圧を制御することが可能な可変容量型ターボチャージャである。   A nozzle vane 9 is provided in the turbine 8b. When the opening degree of the nozzle vane 9 is changed, the flow velocity of the exhaust gas blown to the turbine wheel is changed, thereby changing the turbo output. That is, the turbocharger 8 according to the present embodiment is a variable capacity turbocharger that can control the supercharging pressure by changing the opening degree of the nozzle vane 9.

また、排気通路６には、タービン８ｂをバイパスして排気が流れるように形成されたバイパス通路１７が設けられている。該バイパス通路１７の両端部は、排気通路６におけるタービン８ｂの直上流及び直下流にそれぞれ接続されている。そして、バイパス通路１７にはウェストゲートバルブ（以下、ＷＧＶと称する）１８が設けられている。ＷＧＶ１８は、バイパス通路１７を流れる排気の流量を調整することでタービン８ｂに流入する排気の流量を制御する。尚、バイパス通路１７は、タービン８ｂのタービンホイールをバイパスして排気が流れるように形成されていればよく、その上流側の端部はタービン８ｂに接続されていてもよい。   Further, the exhaust passage 6 is provided with a bypass passage 17 formed so as to bypass the turbine 8b and to flow the exhaust. Both ends of the bypass passage 17 are connected to the exhaust passage 6 directly upstream and downstream of the turbine 8b. The bypass passage 17 is provided with a waste gate valve (hereinafter referred to as WGV) 18. The WGV 18 controls the flow rate of the exhaust gas flowing into the turbine 8 b by adjusting the flow rate of the exhaust gas flowing through the bypass passage 17. The bypass passage 17 may be formed so that the exhaust flows by bypassing the turbine wheel of the turbine 8b, and the upstream end thereof may be connected to the turbine 8b.

排気通路６におけるタービン８ｂより下流側には排気浄化触媒１０が設けられている。また、エキゾーストマニホールド７には排気の圧力を検出する圧力センサ２３が設けられている。本実施例では、該圧力センサ２３によって検出される排気の圧力を過給圧として用いる。   An exhaust purification catalyst 10 is provided downstream of the turbine 8b in the exhaust passage 6. The exhaust manifold 7 is provided with a pressure sensor 23 for detecting the pressure of the exhaust. In the present embodiment, the exhaust pressure detected by the pressure sensor 23 is used as the supercharging pressure.

排気通路６におけるバイパス通路１７の下流側端部の接続部分には排気の温度を検出する温度センサ２４が設けられている。タービン８ｂから排出されたタービン側排気とバイパス通路１７を通過したバイパス側排気とが合流した後の合流排気の温度が該温度センサ２４によって検出される。   A temperature sensor 24 for detecting the temperature of the exhaust gas is provided at the connection portion of the exhaust passage 6 at the downstream end of the bypass passage 17. The temperature sensor 24 detects the temperature of the combined exhaust after the turbine-side exhaust discharged from the turbine 8 b and the bypass-side exhaust that has passed through the bypass passage 17 merge.

本実施例に係る内燃機関１は排気の一部をＥＧＲガスとして吸気系に導入するＥＧＲ装置１４を備えている。ＥＧＲ装置１４は、ＥＧＲ通路１５およびＥＧＲ弁１６を有している。ＥＧＲ通路１５は、その一端がエキゾーストマニホールド７に接続されその他端がインテークマニホールド５に接続されている。該ＥＧＲ通路１５を介してＥＧＲガスがエキゾーストマニホールド７からインテークマニホールド５に導入される。ＥＧＲ弁１６はＥＧＲ通路１５に設けられており、インテークマニホールド５に導入されるＥＧＲガス量が該ＥＧＲ弁１６によって制御される。   The internal combustion engine 1 according to this embodiment includes an EGR device 14 that introduces a part of exhaust gas into the intake system as EGR gas. The EGR device 14 has an EGR passage 15 and an EGR valve 16. The EGR passage 15 has one end connected to the exhaust manifold 7 and the other end connected to the intake manifold 5. EGR gas is introduced from the exhaust manifold 7 into the intake manifold 5 through the EGR passage 15. The EGR valve 16 is provided in the EGR passage 15, and the amount of EGR gas introduced into the intake manifold 5 is controlled by the EGR valve 16.

内燃機関１には電子制御ユニット（ＥＣＵ）２０が併設されている。このＥＣＵ２０は内燃機関１の運転状態等を制御するユニットである。ＥＣＵ２０には、エアフローメータ１１、圧力センサ２３、温度センサ２４、クランクポジションセンサ２１及びアクセル開度センサ２２が電気的に接続されている。各センサの出力信号がＥＣＵ２０に入力される。ＥＣＵ２０は、クランクポジションセンサ２１の検出値に基づいて内燃機関１の機関回転数を算出し、アクセル開度センサ２２の検出値に基づいて内燃機関１の機関負荷を算出する。   The internal combustion engine 1 is provided with an electronic control unit (ECU) 20. The ECU 20 is a unit that controls the operating state of the internal combustion engine 1 and the like. An air flow meter 11, a pressure sensor 23, a temperature sensor 24, a crank position sensor 21, and an accelerator opening sensor 22 are electrically connected to the ECU 20. Output signals from the sensors are input to the ECU 20. The ECU 20 calculates the engine speed of the internal combustion engine 1 based on the detection value of the crank position sensor 21, and calculates the engine load of the internal combustion engine 1 based on the detection value of the accelerator opening sensor 22.

また、ＥＣＵ２０には、各燃料噴射弁３、スロットル弁１２、ノズルベーン９、ＷＧＶ１８及びＥＧＲ弁１６が電気的に接続されている。そして、ＥＣＵ２０によってこれらが制御される。   In addition, each fuel injection valve 3, throttle valve 12, nozzle vane 9, WGV 18, and EGR valve 16 are electrically connected to the ECU 20. These are controlled by the ECU 20.

本実施例においては、バイパス通路１７が本発明に係るバイパス通路に相当し、ＷＧＶ１８が本発明に係る排気バイパス弁に相当する。尚、本発明に係るバイパス弁はＷＧＶに限定されるものではない。例えば、エキゾーストマニホールドに一端が接続され、タービンより下流側の排気通路に他端が接続されるようなバイパス通路を設け、該バイパス通路に排気バイパス弁を設置してもよい。   In this embodiment, the bypass passage 17 corresponds to the bypass passage according to the present invention, and the WGV 18 corresponds to the exhaust bypass valve according to the present invention. The bypass valve according to the present invention is not limited to the WGV. For example, a bypass passage may be provided in which one end is connected to the exhaust manifold and the other end is connected to the exhaust passage downstream of the turbine, and an exhaust bypass valve may be installed in the bypass passage.

また、本実施例においては、圧力センサ２３が本発明に係る過給圧検出手段に相当する。尚、本発明に係る過給圧検出手段はこのような排気の圧力を検出するセンサに限られるものではない。例えば、インテークマニホールドの吸気の圧力を検出する圧力センサを設けた場合は、該圧力センサを本発明に係る過給圧検出手段としてもよい。また、本実施例においては、温度センサ２４が本発明に係る排気温度検出手段に相当する。   In the present embodiment, the pressure sensor 23 corresponds to the supercharging pressure detection means according to the present invention. The supercharging pressure detection means according to the present invention is not limited to such a sensor that detects the exhaust pressure. For example, when a pressure sensor for detecting the intake air pressure of the intake manifold is provided, the pressure sensor may be used as the supercharging pressure detection means according to the present invention. In this embodiment, the temperature sensor 24 corresponds to the exhaust gas temperature detecting means according to the present invention.

（故障判定）
本実施例においては、ＥＣＵ２０が、内燃機関１の運転状態に基づいてノズルベーン９の開度の指令値及びＷＧＶ１８の開度の指令値を決定する。内燃機関１の運転状態とノズルベーン９の開度及びＷＧＶ１８の開度との関係は実験等によって予め定められており、これらの関係がＥＣＵ２０にマップとして記憶されている。ＥＣＵ２０はこのマップからこれらの開度の指令値を決定する。
そして、それぞれの開度がその指令値となるように制御される。 (Failure judgment)
In this embodiment, the ECU 20 determines the command value for the opening degree of the nozzle vane 9 and the command value for the opening degree of the WGV 18 based on the operating state of the internal combustion engine 1. The relationship between the operating state of the internal combustion engine 1 and the opening degree of the nozzle vane 9 and the opening degree of the WGV 18 is determined in advance by experiments or the like, and these relations are stored in the ECU 20 as a map. ECU20 determines the command value of these opening degrees from this map.
And each opening is controlled so that it becomes the command value.

しかしながら、ノズルベーン９又はＷＧＶ１８に故障が生じると、これらの実際の開度が指令値とは異なったものとなる。そのため、これらに故障が生じると、過給圧や排気の背圧を所望の値に制御することが困難となる。また、排気浄化触媒１０に流入する排気の流量や温度も所望の値に制御することが困難となり、該排気浄化触媒１０の劣化の促進あるいは暖気の遅延を招く場合がある。これらの不具合の結果として、排気エミッションやドライバビリティの悪化を招く虞がある。このような不具合を解消するためには、ノズルベーン９又はＷＧＶ１８の故障が発生した場合、それを正確に把握することが重要である。   However, when a failure occurs in the nozzle vane 9 or the WGV 18, these actual opening amounts differ from the command values. Therefore, if a failure occurs in these, it becomes difficult to control the supercharging pressure or the exhaust back pressure to a desired value. Further, it becomes difficult to control the flow rate and temperature of the exhaust gas flowing into the exhaust purification catalyst 10 to a desired value, which may cause deterioration of the exhaust purification catalyst 10 or delay of warm air. As a result of these problems, exhaust emissions and drivability may be deteriorated. In order to eliminate such problems, it is important to accurately grasp when a failure of the nozzle vane 9 or the WGV 18 occurs.

ここで、ノズルベーン９又はＷＧＶ１８の故障が発生した場合の合流排気の温度及び過給圧の挙動について説明する。タービン側排気は、タービン８ｂのタービンホイールの回転に寄与することで、その温度が低下している。そのため、タービン側排気の温度はバイパス側排気の温度に比べて低い。両排気間にこのような温度差があることから、ノズルベーン９又はＷＧＶ１８が故障することで両排気の流量の割合が正常時とは異なるものとなると合流排気の温度が正常時とは異なったものとなる。   Here, the behavior of the combined exhaust gas temperature and the supercharging pressure when a failure of the nozzle vane 9 or the WGV 18 occurs will be described. The turbine-side exhaust contributes to the rotation of the turbine wheel of the turbine 8b, so that the temperature thereof is lowered. Therefore, the temperature of the turbine side exhaust is lower than the temperature of the bypass side exhaust. Since there is such a temperature difference between both exhausts, if the nozzle vane 9 or WGV 18 breaks down and the ratio of the flow rates of both exhausts differs from normal, the temperature of the combined exhaust differs from normal It becomes.

つまり、ノズルベーン９の開弁側故障が生じた場合、又は、ＷＧＶ１８の閉弁側故障が生じた場合は、タービン側排気の流量の割合が増加しバイパス側排気の流量の割合が減少するため、合流排気の温度は正常時よりも低くなる。また、ノズルベーン９の閉弁側故障が生じた場合、又は、ＷＧＶ１８の開弁側故障が生じた場合は、タービン側排気の流量の割合が減少しバイパス側排気の流量の割合が増加するため、合流排気の温度は正常時よりも高くなる。   That is, when the valve opening side failure of the nozzle vane 9 occurs, or when the valve closing side failure of the WGV 18 occurs, the ratio of the flow rate of the turbine side exhaust increases and the ratio of the flow rate of the bypass side exhaust decreases. The temperature of the combined exhaust becomes lower than normal. Further, when the valve closing side failure of the nozzle vane 9 occurs or when the valve opening side failure of the WGV 18 occurs, the ratio of the flow rate of the turbine side exhaust decreases and the ratio of the flow rate of the bypass side exhaust increases. The temperature of the combined exhaust becomes higher than normal.

さらに、ノズルベーン９又はＷＧＶ１８が故障すると、タービンホイールに吹き付けられる排気の流速が正常時とは異なったものとなるため、過給圧も正常時とは異なったものとなる。   Further, when the nozzle vane 9 or the WGV 18 breaks down, the flow rate of the exhaust gas blown to the turbine wheel is different from that in the normal state, and the supercharging pressure is also different from that in the normal state.

つまり、ノズルベーン９の開弁側故障が生じた場合、又は、ＷＧＶ１８の開弁側故障が生じた場合は、タービンホイールに吹き付けられる排気の流速が低下するため、過給圧は正常時よりも低くなる。また、ノズルベーン９の閉弁側故障が生じた場合、又は、ＷＧＶ
１８の閉弁側故障が生じた場合は、タービンホイールに吹き付けられる排気の流速が上昇するため、過給圧は正常時よりも高くなる。 That is, when a valve opening side failure of the nozzle vane 9 occurs, or when a valve opening side failure of the WGV 18 occurs, the flow rate of the exhaust gas blown to the turbine wheel decreases, so the supercharging pressure is lower than normal. Become. Moreover, when the valve closing side failure of the nozzle vane 9 occurs, or WGV
When 18 valve-closing side failure occurs, the flow rate of the exhaust gas blown to the turbine wheel increases, so that the supercharging pressure becomes higher than normal.

そこで、本実施例では、このような故障発生時の合流排気の温度及び過給圧の挙動を利用して、ノズルベーン９の故障とＷＧＶ１８の故障とを区別して故障判定を行なう。以下、本実施例に係るノズルベーン及びＷＧＶの故障判定のフローについて、図２に示すフローチャートに基づいて説明する。本フローは、ＥＣＵ２０に予め記憶されており、ＥＣＵ２０によって所定の間隔で繰り返し実行される。尚、本実施例では、本フローを実行するＥＣＵ２０が、本発明に係る故障判定手段に相当する。   Therefore, in this embodiment, the failure determination is performed by distinguishing between the failure of the nozzle vane 9 and the failure of the WGV 18 by utilizing the behavior of the combined exhaust temperature and the supercharging pressure when such a failure occurs. Hereinafter, the flow of the nozzle vane and WGV failure determination according to the present embodiment will be described based on the flowchart shown in FIG. This flow is stored in advance in the ECU 20, and is repeatedly executed by the ECU 20 at predetermined intervals. In this embodiment, the ECU 20 that executes this flow corresponds to a failure determination unit according to the present invention.

本フローでは、先ずステップＳ１０１において、ノズルベーン９の開度の指令値及びＷＧＶ１８の開度の指令値に基づいて合流排気の温度の基準値である基準排気温度Ｔｇｂａｓｅが算出される。ここで、基準排気温度Ｔｇｂａｓｅとは、ノズルベーン９の開度及びＷＧＶ１８の開度がこれらの指令値の通りとなったとき、即ち正常時の合流排気の温度のことである。ノズルベーン９の開度及びＷＧＶ１８の開度と基準排気温度Ｔｇｂａｓｅとの関係は実験等に基づいて予め求めることが出来る。本実施例では、これらの関係がマップとしてＥＣＵ２０に記憶されている。尚、ステップＳ１０１の処理を実行するＥＣＵ２０が、本発明に係る基準排気温度算出手段に相当する。   In this flow, first, in step S101, a reference exhaust temperature Tgbase, which is a reference value for the temperature of the combined exhaust, is calculated based on the command value for the opening degree of the nozzle vane 9 and the command value for the opening degree of the WGV 18. Here, the reference exhaust temperature Tgbase is the temperature of the combined exhaust gas when the opening degree of the nozzle vane 9 and the opening degree of the WGV 18 are in accordance with these command values. The relationship between the opening degree of the nozzle vane 9 and the opening degree of the WGV 18 and the reference exhaust temperature Tgbase can be obtained in advance based on experiments or the like. In the present embodiment, these relationships are stored in the ECU 20 as a map. In addition, ECU20 which performs the process of step S101 corresponds to the reference | standard exhaust temperature calculation means which concerns on this invention.

次に、ステップＳ１０２において、ノズルベーン９の開度の指令値及びＷＧＶ１８の開度の指令値に基づいて過給圧の基準値である基準過給圧Ｐｃｂａｓｅが算出される。ここで、基準過給圧Ｐｃｂａｓｅとは、ノズルベーン９の開度及びＷＧＶ１８の開度がこれらの指令値の通りとなったとき、即ち正常時の過給圧のことである。ノズルベーン９の開度及びＷＧＶ１８の開度と基準過給圧Ｐｃｂａｓｅとの関係は実験等に基づいて予め求めることが出来る。本実施例ではこれらの関係がマップとしてＥＣＵ２０に記憶されている。尚、ステップＳ１０２の処理を実行するＥＣＵ２０が、本発明に係る基準過給圧算出手段に相当する。   Next, in step S102, a reference boost pressure Pcbase, which is a reference value for the boost pressure, is calculated based on the command value for the opening degree of the nozzle vane 9 and the command value for the opening degree of the WGV 18. Here, the reference supercharging pressure Pcbase is the supercharging pressure when the opening degree of the nozzle vane 9 and the opening degree of the WGV 18 are in accordance with these command values. The relationship between the opening degree of the nozzle vane 9 and the opening degree of the WGV 18 and the reference supercharging pressure Pcbase can be obtained in advance based on experiments or the like. In this embodiment, these relationships are stored in the ECU 20 as a map. In addition, ECU20 which performs the process of step S102 corresponds to the reference | standard supercharging pressure calculation means which concerns on this invention.

次に、ステップＳ１０３において、温度センサ２４によって検出された合流排気の温度Ｔｇが基準排気温度Ｔｇｂａｓｅと同一であり、且つ、圧力センサ２３によって検出された過給圧Ｐｃが基準過給圧Ｐｃｂａｓｅと同一であるか否かを判別する。このステップＳ１０３において肯定判定された場合、ノズルベーン９の開度及びＷＧＶ１８の開度は共にそれぞれの指令値の通りとなっていると判断できる。そのため、次にステップＳ１０７の処理が実行され、ノズルベーン９及びＷＧＶ１８は正常と判定される。   Next, in step S103, the temperature Tg of the combined exhaust detected by the temperature sensor 24 is the same as the reference exhaust temperature Tgbase, and the boost pressure Pc detected by the pressure sensor 23 is the same as the reference boost pressure Pcbase. It is determined whether or not. When an affirmative determination is made in step S103, it can be determined that both the opening degree of the nozzle vane 9 and the opening degree of the WGV 18 are in accordance with the respective command values. Therefore, the process of step S107 is performed next, and it is determined that the nozzle vane 9 and the WGV 18 are normal.

尚、ステップＳ１０３においては、温度センサ２４によって検出された合流排気の温度Ｔｇと基準排気温度Ｔｇｂａｓｅとが完全に同一ではない場合、また、圧力センサ２３によって検出された過給圧Ｐｃと基準過給圧Ｐｃｂａｓｅとが完全に同一ではない場合であっても、これらの値とそれぞれの基準値との差がノズルベーン９及びＷＧＶ１８が正常であると判断できる許容範囲内であれば肯定判定される。   In step S103, if the combined exhaust gas temperature Tg detected by the temperature sensor 24 and the reference exhaust gas temperature Tgbase are not completely the same, the supercharging pressure Pc detected by the pressure sensor 23 and the reference supercharging Even if the pressure Pcbase is not completely the same, a positive determination is made if the difference between these values and the respective reference values is within an allowable range in which it can be determined that the nozzle vanes 9 and WGV 18 are normal.

一方、ステップＳ１０３において否定判定された場合、次にステップＳ１０４の処理が実行される。温度センサ２４によって検出された合流排気の温度Ｔｇが基準排気温度Ｔｇｂａｓｅよりも高いか否かが判別される。このステップＳ１０４において肯定判定された場合、つまり、合流排気の温度Ｔｇが基準排気温度Ｔｇｂａｓｅよりも高い場合、上述した故障発生時の合流排気の温度の挙動から、ノズルベーン９の閉弁側故障又はＷＧＶ１８の開弁側故障が生じていると判断できる。この場合、次にステップＳ１０５の処理が実行される。   On the other hand, if a negative determination is made in step S103, then the process of step S104 is executed. It is determined whether or not the temperature Tg of the combined exhaust detected by the temperature sensor 24 is higher than the reference exhaust temperature Tgbase. If an affirmative determination is made in step S104, that is, if the combined exhaust gas temperature Tg is higher than the reference exhaust gas temperature Tgbase, the failure of the valve closing side of the nozzle vane 9 or the WGV 18 is determined from the behavior of the combined exhaust gas temperature when the failure occurs. It can be determined that a valve-opening side failure has occurred. In this case, the process of step S105 is performed next.

ステップＳ１０５においては、圧力センサ２３によって検出された過給圧Ｐｃが基準過
給圧Ｐｃｂａｓｅよりも高いか否かが判別される。このステップＳ１０５において肯定判定された場合、つまり、過給圧Ｐｃが基準過給圧Ｐｃｂａｓｅよりも高い場合、上述した故障発生時の過給圧の挙動から、ノズルベーン９の閉弁側故障が生じていると判断できる。そのため、次にステップＳ１０８の処理が実行され、ノズルベーン９の閉弁側故障が生じていると判定される。 In step S105, it is determined whether or not the boost pressure Pc detected by the pressure sensor 23 is higher than the reference boost pressure Pcbase. When an affirmative determination is made in step S105, that is, when the supercharging pressure Pc is higher than the reference supercharging pressure Pcbase, a failure on the valve closing side of the nozzle vane 9 occurs due to the behavior of the supercharging pressure when the above-described failure occurs. Can be judged. Therefore, the process of step S108 is performed next, and it is determined that the valve closing side failure of the nozzle vane 9 has occurred.

また、ステップＳ１０５において否定判定された場合、つまり、過給圧Ｐｃが基準過給圧Ｐｃｂａｓｅよりも低い場合、ＷＧＶ１８の開弁側故障が生じていると判断できる。そのため、次にステップＳ１０８の処理が実行され、ＷＧＶ１８の開弁側故障が生じていると判定される。   Further, when a negative determination is made in step S105, that is, when the supercharging pressure Pc is lower than the reference supercharging pressure Pcbase, it can be determined that a valve opening side failure of the WGV 18 has occurred. Therefore, the process of step S108 is performed next, and it is determined that a valve opening side failure of the WGV 18 has occurred.

一方、ステップＳ１０４において否定判定された場合、つまり、合流排気の温度Ｔｇが基準排気温度Ｔｇｂａｓｅよりも低い場合、ノズルベーン９の開弁側故障又はＷＧＶ１８の閉弁側故障が生じていると判断できる。この場合、次にステップＳ１０６の処理が実行される。   On the other hand, if a negative determination is made in step S104, that is, if the combined exhaust gas temperature Tg is lower than the reference exhaust gas temperature Tgbase, it can be determined that a valve-opening failure of the nozzle vane 9 or a valve-closing failure of the WGV 18 has occurred. In this case, the process of step S106 is performed next.

ステップＳ１０６においては、圧力センサ２３によって検出された過給圧Ｐｃが基準過給圧Ｐｃｂａｓｅよりも低いか否かが判別される。このステップＳ１０６において肯定判定された場合、つまり、過給圧Ｐｃが基準過給圧Ｐｃｂａｓｅよりも低い場合、ノズルベーン９の開弁側故障が生じていると判断できる。そのため、次にステップＳ１１０の処理が実行され、ノズルベーン９の開弁側故障が生じていると判定される。   In step S106, it is determined whether or not the boost pressure Pc detected by the pressure sensor 23 is lower than the reference boost pressure Pcbase. When an affirmative determination is made in step S106, that is, when the supercharging pressure Pc is lower than the reference supercharging pressure Pcbase, it can be determined that a valve-opening side failure of the nozzle vane 9 has occurred. Therefore, the process of step S110 is performed next, and it is determined that a valve opening side failure of the nozzle vane 9 has occurred.

また、ステップＳ１０６において否定判定された場合、つまり、過給圧Ｐｃが基準過給圧Ｐｃｂａｓｅよりも高い場合、ＷＧＶ１８の閉弁側故障が生じていると判断できる。そのため、次にステップＳ１１１の処理が実行され、ＷＧＶ１８の閉弁側故障が生じていると判定される。   Further, when a negative determination is made in step S106, that is, when the supercharging pressure Pc is higher than the reference supercharging pressure Pcbase, it can be determined that the valve closing side failure of the WGV 18 has occurred. Therefore, the process of step S111 is executed next, and it is determined that a valve closing side failure of the WGV 18 has occurred.

以上説明したフローによれば、ノズルベーン９の故障とＷＧＶ１８の故障とを区別して故障判定を行うことができる。   According to the flow described above, the failure determination can be performed by distinguishing between the failure of the nozzle vane 9 and the failure of the WGV 18.

１・・・内燃機関
２・・・気筒
３・・・燃料噴射弁
４・・・吸気通路
５・・・インテークマニホールド
６・・・排気通路
７・・・エキゾーストマニホールド
８・・・ターボチャージャ
８ａ・・コンプレッサ
８ｂ・・タービン
９・・・ノズルベーン
１０・・排気浄化触媒
１１・・エアフローメータ
１２・・スロットル弁
１４・・ＥＧＲ装置
１５・・ＥＧＲ通路
１６・・ＥＧＲ弁
１７・・バイパス通路
１８・・ウェストゲートバルブ（ＷＧＶ）
２０・・ＥＣＵ
２１・・クランクポジションセンサ
２２・・アクセル開度センサ
２３・・圧力センサ
２４・・温度センサ DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 2 ... Cylinder 3 ... Fuel injection valve 4 ... Intake passage 5 ... Intake manifold 6 ... Exhaust passage 7 ... Exhaust manifold 8 ... Turbocharger 8a -Compressor 8b-Turbine 9 ... Nozzle vane 10-Exhaust purification catalyst 11-Air flow meter 12-Throttle valve 14-EGR device 15-EGR passage 16-EGR valve 17-Bypass passage 18- Westgate valve (WGV)
20. ・ ECU
21 .... Crank position sensor 22 ... Accelerator opening sensor 23 ... Pressure sensor 24 ... Temperature sensor

Claims (6)

内燃機関の排気通路に設けられており、ノズルベーンを有する過給機のタービンと、
該タービンのタービンホイールをバイパスして排気が流れるように形成されたバイパス通路と、
該バイパス通路に設けられ該バイパス通路を流れる排気の流量を調整する排気バイパス弁と、を有する内燃機関の排気系の故障判定装置であって、
前記タービンから排出された排気と前記バイパス通路を通過した排気とが合流した後の排気の温度を検出する排気温度検出手段と、
過給圧を検出する過給圧検出手段と、
前記排気温度検出手段によって検出された排気の温度及び前記過給圧検出手段によって検出された過給圧に基づいて、前記ノズルベーンの故障と前記排気バイパス弁の故障とを区別して判定する故障判定手段と、
を備えたことを特徴とする内燃機関の排気系の故障判定装置。 A turbocharger turbine provided in an exhaust passage of the internal combustion engine, having a nozzle vane;
A bypass passage formed so that exhaust flows by bypassing the turbine wheel of the turbine;
A failure determination device for an exhaust system of an internal combustion engine, comprising: an exhaust bypass valve provided in the bypass passage and configured to adjust a flow rate of exhaust gas flowing through the bypass passage;
Exhaust temperature detection means for detecting the temperature of the exhaust after the exhaust discharged from the turbine and the exhaust that has passed through the bypass passage merged;
A supercharging pressure detecting means for detecting a supercharging pressure;
A failure determination unit that distinguishes between a failure of the nozzle vane and a failure of the exhaust bypass valve based on the temperature of the exhaust detected by the exhaust temperature detection unit and the boost pressure detected by the boost pressure detection unit. When,
A failure determination device for an exhaust system of an internal combustion engine, comprising: 前記ノズルベーンの開度の指令値及び前記排気バイパス弁の開度の指令値に基づいて、前記タービンから排出された排気と前記バイパス通路を通過した排気とが合流した後の排気の温度の基準値である基準排気温度を算出する基準排気温度算出手段と、
前記ノズルベーンの開度の指令値及び前記排気バイパス弁の開度の指令値に基づいて、過給圧の基準値である基準過給圧を算出する基準過給圧算出手段と、を更に備え、
前記故障判定手段が、前記排気温度検出手段によって検出された排気の温度と前記基準排気温度とを比較すると共に、前記過給圧検出手段によって検出された過給圧と前記基準過給圧とを比較することで、前記ノズルベーンの故障と前記排気バイパス弁の故障とを区別して判定することを特徴とする請求項１に記載の内燃機関の排気系の故障判定装置。 Based on the command value of the opening degree of the nozzle vane and the command value of the opening degree of the exhaust bypass valve, the reference value of the temperature of the exhaust gas after the exhaust gas exhausted from the turbine and the exhaust gas passing through the bypass passage are merged A reference exhaust gas temperature calculating means for calculating a reference exhaust gas temperature,
A reference boost pressure calculating means for calculating a reference boost pressure that is a reference value of the boost pressure based on the command value of the opening degree of the nozzle vane and the command value of the opening degree of the exhaust bypass valve;
The failure determination means compares the exhaust gas temperature detected by the exhaust gas temperature detection means and the reference exhaust gas temperature, and compares the supercharging pressure detected by the supercharging pressure detection means and the reference supercharging pressure. The failure determination device for an exhaust system of an internal combustion engine according to claim 1, wherein the determination is made by comparing the failure of the nozzle vane and the failure of the exhaust bypass valve by comparison. 前記故障判定手段が、前記排気温度検出手段によって検出された排気の温度が前記基準排気温度より高く、且つ、前記過給圧検出手段によって検出された過給圧が前記基準過給圧より高いときは、前記ノズルベーンの閉弁側故障が生じていると判定することを特徴とする請求項２に記載の内燃機関の排気系の故障判定装置。   When the failure determination means has a temperature of the exhaust gas detected by the exhaust gas temperature detection means higher than the reference exhaust gas temperature and a boost pressure detected by the boost pressure detection means is higher than the reference boost pressure. 3. The failure determination device for an exhaust system of an internal combustion engine according to claim 2, wherein it is determined that a failure on the valve closing side of the nozzle vane has occurred. 前記故障判定手段が、前記排気温度検出手段によって検出された排気の温度が前記基準排気温度より高く、且つ、前記過給圧検出手段によって検出された過給圧が前記基準過給圧より低いときは、前記排気バイパス弁の開弁側故障が生じていると判定することを特徴とする請求項２に記載の内燃機関の排気系の故障判定装置。   When the failure determination means has a temperature of the exhaust gas detected by the exhaust gas temperature detection means higher than the reference exhaust gas temperature, and a boost pressure detected by the boost pressure detection means is lower than the reference boost pressure. 3. The failure determination device for an exhaust system of an internal combustion engine according to claim 2, wherein it is determined that a failure on the valve opening side of the exhaust bypass valve has occurred. 前記故障判定手段が、前記排気温度検出手段によって検出された排気の温度が前記基準排気温度より低く、且つ、前記過給圧検出手段によって検出された過給圧が前記基準過給圧より高いときは、前記排気バイパス弁の閉弁側故障が生じていると判定することを特徴とする請求項２に記載の内燃機関の排気系の故障判定装置。   When the failure determination means has an exhaust temperature detected by the exhaust temperature detection means lower than the reference exhaust temperature and a boost pressure detected by the boost pressure detection means is higher than the reference boost pressure. 3. The failure determination device for an exhaust system of an internal combustion engine according to claim 2, wherein it is determined that a failure on the valve closing side of the exhaust bypass valve has occurred. 前記故障判定手段が、前記排気温度検出手段によって検出された排気の温度が前記基準排気温度より低く、且つ、前記過給圧検出手段によって検出された過給圧が前記基準過給圧より低いときは、前記ノズルベーンの開弁側故障が生じていると判定することを特徴とする請求項２に記載の内燃機関の排気系の故障判定装置。   When the failure determination means has an exhaust gas temperature detected by the exhaust gas temperature detection means lower than the reference exhaust gas temperature, and a supercharging pressure detected by the supercharging pressure detection means is lower than the reference supercharging pressure. 3. The failure determination device for an exhaust system of an internal combustion engine according to claim 2, wherein it is determined that a failure on the valve opening side of the nozzle vane has occurred.
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FR2947863B1 (en) 2016-06-17
FR2947863A1 (en) 2011-01-14
JP5326887B2 (en) 2013-10-30
DE102010031195B4 (en) 2019-10-31

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