JP2010138788A - Egr device for internal combustion engine - Google Patents

Egr device for internal combustion engine Download PDF

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JP2010138788A
JP2010138788A JP2008315643A JP2008315643A JP2010138788A JP 2010138788 A JP2010138788 A JP 2010138788A JP 2008315643 A JP2008315643 A JP 2008315643A JP 2008315643 A JP2008315643 A JP 2008315643A JP 2010138788 A JP2010138788 A JP 2010138788A
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egr
cooler
temperature
egr cooler
internal combustion
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Katsuyuki Nagoshi
勝之 名越
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Hino Motors Ltd
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    • 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
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Abstract

<P>PROBLEM TO BE SOLVED: To provide an EGR device for an internal combustion engine, appropriately detecting efficiency deterioration of an EGR cooler. <P>SOLUTION: This EGR device for the internal combustion engine includes an EGR pipe 16 in order to return EGR gas from the exhaust passage 5 of the engine 1 to an air supply passage 3 through an EGR cooler 17 and an EGR valve 19. The EGR device is so configured that based on the premise that the large amount of EGR gas is led to flow by opening of the EGR valve 19 and EGR temperature is secured, EGR gas temperature on the side of the outlet of the EGR cooler 17 is compared with a threshold to detect the efficiency deterioration of the EGR cooler 17. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、ＥＧＲガスを供給してＮＯｘの発生を効果的に低減するようにした内燃機関のＥＧＲ装置に関する。   The present invention relates to an EGR device for an internal combustion engine that supplies EGR gas to effectively reduce the generation of NOx.

従来より、内燃機関において、排気ガスの一部（以下「ＥＧＲガス」という）を給気系に還流して燃焼を緩慢にし、燃焼温度を下げることによりＮＯｘの低減を図るようにした排気ガス再循環装置（ＥＧＲ装置）が広く用いられている。   Conventionally, in an internal combustion engine, a part of the exhaust gas (hereinafter referred to as “EGR gas”) is recirculated to the supply system to slow down combustion, and the exhaust gas re-regeneration is intended to reduce NOx by lowering the combustion temperature. Circulation devices (EGR devices) are widely used.

図４は過給機付き内燃機関の一例を示したもので、この内燃機関は、エンジン１のインテークマニホールド２に接続された給気通路３及びイクゾーストマニホールド４に接続された排気通路５を有している。前記排気通路５には排気ガス６により駆動されるタービン７を備えると共に前記給気通路３には該タービン７によって圧縮空気９を生成する圧縮機８を設け、タービン７及び圧縮機８によりターボチャージャからなる過給機１０を構成し、過給機１０の圧縮機８で圧縮した圧縮空気９を前記給気通路３に供給するようにしている。図４中、符号１１はエアクリーナ、１２はインタークーラ、１３はエンジン１の気筒、１４は燃料噴射装置である。   FIG. 4 shows an example of an internal combustion engine with a supercharger. This internal combustion engine has an air supply passage 3 connected to an intake manifold 2 of the engine 1 and an exhaust passage 5 connected to an exhaust manifold 4. is doing. The exhaust passage 5 is provided with a turbine 7 driven by exhaust gas 6, and the air supply passage 3 is provided with a compressor 8 that generates compressed air 9 by the turbine 7. The supercharger 10 which consists of this is comprised, and the compressed air 9 compressed with the compressor 8 of the supercharger 10 is supplied to the said air supply path 3. As shown in FIG. In FIG. 4, reference numeral 11 is an air cleaner, 12 is an intercooler, 13 is a cylinder of the engine 1, and 14 is a fuel injection device.

前記給気通路３と排気通路５との間にはＥＧＲ手段１５が設けられている。図４のＥＧＲ手段１５は、インテークマニホールド２と前記イクゾーストマニホールド４との間をＥＧＲ配管１６によって接続しており、該ＥＧＲ配管１６には、ＥＧＲクーラ１７が備えられると共に、アクチュエータ１８により開閉するＥＧＲバルブ１９が設けられている。   EGR means 15 is provided between the air supply passage 3 and the exhaust passage 5. The EGR means 15 in FIG. 4 is connected between the intake manifold 2 and the exhaust manifold 4 by an EGR pipe 16. The EGR pipe 16 is provided with an EGR cooler 17 and is opened and closed by an actuator 18. An EGR valve 19 is provided.

図示しない運転席のアクセルには、アクセル開度をエンジン１の負荷として検出するアクセルセンサ（負荷センサ）２０が備えられていると共に、エンジン１の適宜位置には、その回転数を検出する回転センサ２１が装備されており、これらアクセルセンサ２０及び回転センサ２１からのアクセル開度信号２０ａ及び回転数信号２１ａが、エンジン制御コンピュータ（ＥＣＵ：Electronic Control Unit）を成す制御装置２２に対し入力されるようになっている。   An accelerator in a driver's seat (not shown) is provided with an accelerator sensor (load sensor) 20 that detects the accelerator opening as a load of the engine 1, and a rotation sensor that detects the rotational speed at an appropriate position of the engine 1. The accelerator opening signal 20a and the rotation speed signal 21a from the accelerator sensor 20 and the rotation sensor 21 are input to a control device 22 constituting an engine control computer (ECU: Electronic Control Unit). It has become.

一方、制御装置２２においては、ＥＧＲバルブ１９のアクチュエータ１８に対し開度を指令する開度指令信号１８ａが出力されるようになっている。また各気筒１３に燃料を噴射する燃料噴射装置１４に向け燃料の噴射タイミング及び噴射量を指令する燃料噴射信号１４ａが出力されるようになっている。   On the other hand, in the control device 22, an opening degree command signal 18 a for instructing the opening degree to the actuator 18 of the EGR valve 19 is output. Further, a fuel injection signal 14a for instructing the fuel injection timing and the injection amount is output to a fuel injection device 14 for injecting fuel into each cylinder 13.

エンジン１の運転時には、アクセル開度信号２０ａ及び回転数信号２１ａに基づいて制御装置２２からＥＧＲバルブ１９を制御し、ＥＧＲバルブ１９の開度をエンジン１の運転状態に応じた位置に保持し、これによりＥＧＲガスが給気通路３に再循環されて排気ガスのＮＯｘ低減が図られている。   During operation of the engine 1, the EGR valve 19 is controlled from the control device 22 based on the accelerator opening signal 20 a and the rotation speed signal 21 a, and the opening of the EGR valve 19 is held at a position corresponding to the operating state of the engine 1, As a result, the EGR gas is recirculated through the supply passage 3 to reduce NOx in the exhaust gas.

また先行技術文献の中には、ＥＧＲ装置において煤の堆積に伴うＥＧＲクーラの故障を検出するものが考えられている（例えば、特許文献１参照）。
特開２０００−２１３４２３号公報 In addition, among prior art documents, there is considered an EGR device that detects a failure of an EGR cooler associated with soot accumulation (see, for example, Patent Document 1).
JP 2000-213423 A

しかしながら、このような従来のＥＧＲ装置においては、ＥＧＲクーラ１７の効率低下を適切に検出することできないという問題があった。また先行技術文献のごとくＥＧＲクーラの故障を検出するものは、ＥＧＲバルブの開閉に伴ってＥＧＲクーラのクーラ温度がどのように変化するかを測定するものであるため、測定条件がＥＧＲバルブの開閉操作に依存し、ＥＧＲクーラの効率低下や故障を容易に測定することができないという問題があった。   However, such a conventional EGR apparatus has a problem that it is impossible to appropriately detect a decrease in efficiency of the EGR cooler 17. Also, as in the prior art document, what detects an EGR cooler failure is to measure how the EGR cooler temperature changes as the EGR valve opens and closes. Depending on the operation, there has been a problem that the EGR cooler cannot be easily measured for efficiency reduction or failure.

本発明は上述の実情に鑑みてなしたもので、ＥＧＲクーラの効率低下を容易且つ適切に検出する内燃機関のＥＧＲ装置を提供することを目的としている。   The present invention has been made in view of the above-described circumstances, and an object thereof is to provide an EGR device for an internal combustion engine that easily and appropriately detects a decrease in efficiency of an EGR cooler.

本発明は、エンジンの排気通路から給気通路へＥＧＲクーラ及びＥＧＲバルブを介してＥＧＲガスを戻すようにＥＧＲ配管を備えた内燃機関のＥＧＲ装置であって、
ＥＧＲバルブの開度によりＥＧＲガスを多量に流してＥＧＲ温度を確保する条件を前提条件とし、ＥＧＲクーラの出口側ＥＧＲガス温度を閾値と比較してＥＧＲクーラの効率低下を検出するように構成するものである。 The present invention is an EGR device for an internal combustion engine provided with an EGR pipe so as to return EGR gas from an exhaust passage of an engine to an air supply passage via an EGR cooler and an EGR valve.
The precondition is that the EGR gas is flowed in a large amount depending on the opening degree of the EGR valve to ensure the EGR temperature, and the EGR cooler outlet side EGR gas temperature is compared with a threshold value to detect a decrease in efficiency of the EGR cooler. Is.

本発明において、ＥＧＲクーラの出口側ＥＧＲガス温度が閾値を超え、且つ閾値を超えている状態が判定基準時間以上である場合に、ＥＧＲクーラに効率低下があると判断するように構成することが好ましい。   In the present invention, when the EGR gas temperature at the outlet side of the EGR cooler exceeds the threshold and the state where the EGR gas exceeds the threshold is equal to or longer than the determination reference time, the EGR cooler is configured to determine that there is a decrease in efficiency. preferable.

本発明において、ＥＧＲバルブの開度によりＥＧＲガスを多量に流してＥＧＲ温度を確保する条件を、燃料の噴射量及びエンジン回転数が所定の領域内にあることに基づいて判定するように構成することが好ましい。   In the present invention, the condition for ensuring the EGR temperature by flowing a large amount of EGR gas according to the opening of the EGR valve is determined based on the fuel injection amount and the engine speed being within a predetermined range. It is preferable.

而して、ＥＧＲガスを多量に流してＥＧＲ温度を確保する条件を前提条件とすることにより、ＥＧＲクーラが劣化して効率が低下した時の出口側ＥＧＲガス温度と、ＥＧＲクーラが正常である時の出口側ＥＧＲガス温度とについて温度差を生じ、ＥＧＲクーラの効率低下時と正常時とを容易に区別することが可能となる。またＥＧＲクーラが劣化して効率が低下した時のＥＧＲクーラの出口側ＥＧＲガス温度を閾値として、実測の出口側ＥＧＲガス温度と比較し、ＥＧＲクーラの効率低下を検出し得る。   Thus, the precondition is that the EGR gas is flowed in a large amount to ensure the EGR temperature, so that the outlet side EGR gas temperature when the EGR cooler deteriorates and the efficiency is lowered, and the EGR cooler is normal. A temperature difference is generated with respect to the outlet-side EGR gas temperature at the time, and it becomes possible to easily distinguish between when the efficiency of the EGR cooler is reduced and when it is normal. Further, the EGR cooler can be detected by comparing the measured EGR gas temperature with the measured outlet side EGR gas temperature using the EGR cooler outlet side EGR gas temperature when the EGR cooler deteriorates and the efficiency is lowered as a threshold value.

上記した本発明の内燃機関のＥＧＲ装置によれば、ＥＧＲガスを多量に流してＥＧＲ温度を確保する条件を前提条件とし、ＥＧＲクーラの出口側ＥＧＲガス温度を閾値と比較するので、ＥＧＲクーラの効率低下を容易且つ適切に検出することができるという優れた効果を奏し得る。   According to the EGR device for an internal combustion engine of the present invention described above, since the EGR temperature is ensured by flowing a large amount of EGR gas and the EGR gas temperature on the outlet side of the EGR cooler is compared with a threshold value, It is possible to obtain an excellent effect that it is possible to easily and appropriately detect a decrease in efficiency.

以下、本発明の実施の形態を図面を参照しつつ説明する。   Hereinafter, embodiments of the present invention will be described with reference to the drawings.

図１〜図３は本発明を実施する形態例を示すものであり、図中、図４と同一の符号を付した部分は同一物を表している。   1 to 3 show an embodiment in which the present invention is implemented. In the figure, the same reference numerals as those in FIG. 4 denote the same components.

実施の形態例の内燃機関のＥＧＲ装置は、エンジン１の排気通路５から給気通路３へＥＧＲガスを戻すように給気通路３と排気通路５との間にＥＧＲ手段１５が設けられている。ＥＧＲ手段１５は、給気通路３がインテークマニホールド２とイクゾーストマニホールド４との間をＥＧＲ配管１６によって接続しており、ＥＧＲ手段１５のＥＧＲ配管１６には、ＥＧＲクーラ１７が備えられると共に、アクチュエータ１８により開閉するＥＧＲバルブ１９が設けられている。   In the EGR device for an internal combustion engine of the embodiment, EGR means 15 is provided between the air supply passage 3 and the exhaust passage 5 so as to return EGR gas from the exhaust passage 5 of the engine 1 to the air supply passage 3. . The EGR means 15 has an air supply passage 3 connecting the intake manifold 2 and the exhaust manifold 4 by an EGR pipe 16. The EGR pipe 16 of the EGR means 15 is provided with an EGR cooler 17 and an actuator. An EGR valve 19 that is opened and closed by 18 is provided.

ＥＧＲ配管１６のＥＧＲクーラ１７の下流側からＥＧＲバルブ１９までの間には、ＥＧＲ出口温度センサ２３を備え、ＥＧＲクーラ１７の出口側ＥＧＲガス温度を検出するようにしている。またエンジン１には、冷却水の温度を検出する水温センサ２４が装備されている。   An EGR outlet temperature sensor 23 is provided between the EGR pipe 16 downstream of the EGR cooler 17 and the EGR valve 19 so as to detect the outlet EGR gas temperature of the EGR cooler 17. The engine 1 is also equipped with a water temperature sensor 24 that detects the temperature of the cooling water.

また図示しない運転席のアクセルには、アクセル開度をエンジン１の負荷として検出するアクセルセンサ（負荷センサ）２０が備えられていると共に、エンジン１の適宜位置には、その回転数を検出する回転センサ２１が装備されている。   An accelerator in a driver's seat (not shown) is provided with an accelerator sensor (load sensor) 20 that detects the accelerator opening as a load of the engine 1, and a rotation that detects the rotational speed at an appropriate position of the engine 1. A sensor 21 is provided.

更に、ＥＧＲ出口温度センサ２３から出口側ＥＧＲガス温度信号２３ａ、水温センサ２４からの冷却水温度信号２４ａ、及びアクセルセンサ２０及び回転センサ２１からのアクセル開度信号２０ａ及び回転数信号２１ａが、エンジン制御コンピュータ（ＥＣＵ：Electronic Control Unit）を成す制御装置２５に対し入力されるようになっている。   Further, the EGR outlet temperature sensor 23 outputs the outlet side EGR gas temperature signal 23a, the coolant temperature signal 24a from the water temperature sensor 24, the accelerator opening signal 20a and the rotation speed signal 21a from the accelerator sensor 20 and the rotation sensor 21, and It is input to a control device 25 constituting a control computer (ECU: Electronic Control Unit).

一方、制御装置２５においては、入力された信号からＥＧＲバルブ１９のアクチュエータ１８に対し開度を指令する開度指令信号１８ａが出力されると共に、故障ランプ等の表示手段２６に表示信号２６ａが出力されるようになっている。また各気筒１３に燃料を噴射する燃料噴射装置１４に向け燃料の噴射タイミング及び噴射量を指令する燃料噴射信号１４ａが出力されるようになっている。   On the other hand, in the control device 25, an opening command signal 18a for commanding the opening to the actuator 18 of the EGR valve 19 is output from the input signal, and a display signal 26a is output to the display means 26 such as a failure lamp. It has come to be. Further, a fuel injection signal 14a for instructing the fuel injection timing and the injection amount is output to a fuel injection device 14 for injecting fuel into each cylinder 13.

また制御装置２５には、図２に示すフローの制御が入力されると共に、ＥＧＲバルブ１９の開度によりＥＧＲガスを多量に流してＥＧＲ温度を確保する条件を前提条件として判断し得るように、図３に示す燃料噴射信号１４ａ（燃料の噴射量）及び回転数信号２１ａ（エンジン回転数）の関係が入力されている。   In addition, the control of the flow shown in FIG. 2 is input to the control device 25, and the condition for ensuring the EGR temperature by flowing a large amount of EGR gas depending on the opening degree of the EGR valve 19 can be determined as a precondition. The relationship between the fuel injection signal 14a (fuel injection amount) and the rotational speed signal 21a (engine rotational speed) shown in FIG. 3 is input.

以下、本発明の実施の形態例の作用を説明する。   The operation of the embodiment of the present invention will be described below.

ＮＯｘの発生を低減する際には、エンジン１の運転域におけるアクセル開度信号２０ａ及び回転数信号２１ａ等に基づいて制御装置２５がＥＧＲバルブ１９のアクチュエータ１８に開度指令信号１８ａを出し、ＥＧＲ配管１６の開度を調整して排気の一部をイクゾーストマニホールド４からＥＧＲ配管１６を介してインテークマニホールド２へ流入させ、気筒１３内の燃焼温度の低下を図ってＮＯｘの発生を低減する。   When reducing the generation of NOx, the control device 25 issues an opening command signal 18a to the actuator 18 of the EGR valve 19 based on the accelerator opening signal 20a and the rotation speed signal 21a in the operating range of the engine 1, and the EGR The opening degree of the pipe 16 is adjusted, and a part of the exhaust gas is caused to flow from the exhaust manifold 4 to the intake manifold 2 via the EGR pipe 16 to reduce the combustion temperature in the cylinder 13 and reduce the generation of NOx.

また制御装置２５は、エンジンスタートに伴い、図２の手順に従って以下の処理を行う。   The control device 25 performs the following processing according to the procedure of FIG.

最初に、検出前の前提条件としてＥＧＲバルブ１９の開度によりＥＧＲガスを多量に流してＥＧＲ温度を確保する条件になっているか否かを判断する。具体的には、燃料噴射信号１４ａ（燃料の噴射量）及び回転数信号２１ａ（エンジン回転数）で規定された関数等で処理し、燃料の噴射量及びエンジン回転数が図３の所定の領域内にあるか否かにより判断する（ステップＳ１）。ここで、図３に示す燃料の噴射量とエンジン回転数との関係は、実験データに基づき予め求められたものであり、燃料の噴射量及びエンジン回転数で規定される領域において、ＥＧＲガスを多量に流してＥＧＲ温度が確保できる領域を設定している。また制御装置２５は、燃料噴射信号１４ａ（燃料の噴射量）及び回転数信号２１ａ（エンジン回転数）をエンジンの水温等により適宜補正することも可能となっている。   First, as a precondition before detection, it is determined whether or not the EGR temperature is ensured by flowing a large amount of EGR gas according to the opening of the EGR valve 19. Specifically, processing is performed with a function defined by the fuel injection signal 14a (fuel injection amount) and the rotational speed signal 21a (engine rotational speed), and the fuel injection amount and the engine rotational speed are within a predetermined range of FIG. Judgment is made based on whether it is within (step S1). Here, the relationship between the fuel injection amount and the engine speed shown in FIG. 3 is obtained in advance based on experimental data. In the region defined by the fuel injection amount and the engine speed, the EGR gas is A region where EGR temperature can be secured by flowing a large amount is set. Further, the control device 25 can appropriately correct the fuel injection signal 14a (fuel injection amount) and the rotational speed signal 21a (engine rotational speed) according to the engine water temperature or the like.

そして燃料噴射信号１４ａ（燃料の噴射量）及び回転数信号２１ａ（エンジン回転数）が所定の領域にない場合（ステップＳ１のＮＯ）には、ＥＧＲクーラ１７が劣化して効率が低下した時の出口側ＥＧＲガス温度と、ＥＧＲクーラ１７が正常である時の出口側ＥＧＲガス温度とについて適切な温度差を生じないとして、システム確認不要の段階へ移行し、ＥＧＲクーラ１７の効率低下等の有無を確認することなく終了する（ステップＳ２）。   If the fuel injection signal 14a (fuel injection amount) and the rotational speed signal 21a (engine rotational speed) are not within the predetermined range (NO in step S1), the EGR cooler 17 deteriorates and the efficiency is reduced. Assuming that an appropriate temperature difference does not occur between the outlet side EGR gas temperature and the outlet side EGR gas temperature when the EGR cooler 17 is normal, the system shifts to a stage where system confirmation is unnecessary, and whether or not the efficiency of the EGR cooler 17 is reduced. The process ends without confirming (step S2).

一方、燃料噴射信号１４ａ（燃料の噴射量）及び回転数信号２１ａ（エンジン回転数）が所定の領域にある場合（ステップＳ１のＹＥＳ）には、ＥＧＲクーラ１７が劣化して効率が低下した時の出口側ＥＧＲガス温度と、ＥＧＲクーラ１７が正常である時の出口側ＥＧＲガス温度とについて適切な温度差を生じるとして、システム確認（ＥＧＲクーラ１７の確認）の段階へ移行し、ＥＧＲクーラ１７の効率低下等の有無を確認する（ステップＳ３）。   On the other hand, when the fuel injection signal 14a (fuel injection amount) and the rotational speed signal 21a (engine rotational speed) are in a predetermined region (YES in step S1), the EGR cooler 17 deteriorates and the efficiency decreases. Assuming that an appropriate temperature difference occurs between the outlet EGR gas temperature of the engine and the outlet EGR gas temperature when the EGR cooler 17 is normal, the system proceeds to the system confirmation (confirmation of the EGR cooler 17) stage, and the EGR cooler 17 Whether or not there is a decrease in efficiency is confirmed (step S3).

次にＥＧＲクーラ１７の効率低下等の有無を確認する段階（ステップＳ３）へ移行した後には、ＥＧＲクーラ１７が劣化して効率が低下した時のＥＧＲクーラの出口側ＥＧＲガス温度を閾値として、ＥＧＲクーラ１７の出口側ＥＧＲガス温度が所定の閾値を超えているか否かを判断する（ステップＳ４）。ここで閾値は、ＥＧＲクーラ１７の効率低下時の温度に限定されるものではなく、ＥＧＲクーラ１７の修理や交換が必要な異常時の温度を含むものでも良いし、ＥＧＲクーラ１７の効率低下時とＥＧＲクーラ１７の異常時とを区別するものでも良い。   Next, after proceeding to the step of confirming whether or not the efficiency of the EGR cooler 17 is lowered (step S3), the EGR cooler outlet EGR gas temperature when the EGR cooler 17 deteriorates and the efficiency is lowered is used as a threshold value. It is determined whether or not the outlet side EGR gas temperature of the EGR cooler 17 exceeds a predetermined threshold value (step S4). Here, the threshold value is not limited to the temperature at which the efficiency of the EGR cooler 17 is reduced, but may include a temperature at the time of an abnormality that requires repair or replacement of the EGR cooler 17, or when the efficiency of the EGR cooler 17 is reduced. May be distinguished from when the EGR cooler 17 is abnormal.

そして出口側ＥＧＲガス温度が所定の閾値よりも低い場合（ステップＳ４のＮＯ）には、システム正常の段階へ移行し、ＥＧＲクーラ１７に効率低下や異常が存在する可能性がないとして終了する（ステップＳ５）。一方、出口側ＥＧＲガス温度が所定の閾値を超えた場合（ステップＳ４のＹＥＳ）には、ＥＧＲクーラ１７に効率低下や異常が存在する可能性があるとして次の段階へ移行する。   When the outlet side EGR gas temperature is lower than the predetermined threshold (NO in step S4), the system shifts to a normal system stage, and the EGR cooler 17 is terminated because there is no possibility of a decrease in efficiency or abnormality ( Step S5). On the other hand, when the outlet side EGR gas temperature exceeds the predetermined threshold (YES in step S4), the EGR cooler 17 is assumed to have a decrease in efficiency or an abnormality, and the process proceeds to the next stage.

次の段階では、出口側ＥＧＲガス温度が所定の閾値を超えた時点からカウントを開始し（ステップＳ６）、ＥＧＲクーラ１７の出口側ＥＧＲガス温度が閾値を超えている状態が判定基準時間（所定値）以上であるか否かを判断する（ステップＳ７）。   In the next stage, counting is started from the time when the outlet side EGR gas temperature exceeds a predetermined threshold (step S6), and the state where the outlet side EGR gas temperature of the EGR cooler 17 exceeds the threshold is determined as a reference time (predetermined time). Value) or more is determined (step S7).

ＥＧＲクーラ１７の出口側ＥＧＲガス温度が閾値を超えている状態が判定基準時間を満たさない場合（ステップＳ７のＮＯ）には、システム正常の段階へ移行し、ＥＧＲクーラ１７の効率低下や異常でないと判断して終了する（ステップＳ５）。   When the state in which the outlet side EGR gas temperature of the EGR cooler 17 exceeds the threshold does not satisfy the determination reference time (NO in step S7), the system shifts to the normal stage, and the efficiency of the EGR cooler 17 is not reduced or abnormal. And the process ends (step S5).

一方、ＥＧＲクーラ１７の出口側ＥＧＲガス温度が閾値を超えている状態が判定基準時間以上の場合（ステップＳ７のＹＥＳ）には、システム異常の段階へ移行し、ＥＧＲクーラ１７の効率低下や異常があると判断する（ステップＳ８）。   On the other hand, when the state in which the EGR gas temperature at the outlet side of the EGR cooler 17 exceeds the threshold is equal to or longer than the determination reference time (YES in step S7), the system shifts to the system abnormality stage, and the EGR cooler 17 is inefficient It is determined that there is (step S8).

システム異常の段階へ移行した際（ステップＳ８）には、制御装置２５が故障ランプ等の表示手段２６に表示信号２６ａを出力し、表示手段２６に点灯等の表示をして異常がある旨を知らせる（ステップＳ９）。   When the system abnormality stage is entered (step S8), the control device 25 outputs a display signal 26a to the display means 26 such as a failure lamp, and the display means 26 is turned on to indicate that there is an abnormality. Notify (step S9).

而して、このように実施の形態例によれば、ＥＧＲバルブ１９の開度によりＥＧＲガスを多量に流してＥＧＲ温度を確保する条件を前提条件とし、ＥＧＲクーラの出口側ＥＧＲガス温度を閾値と比較するので、ＥＧＲクーラの効率低下や異常を容易且つ適切に検出することができる。またＥＧＲクーラ１７の出口側ＥＧＲガス温度を用いるので、ＥＧＲクーラ１７の効率低下や異常を好適に検出することができる。   Thus, according to the embodiment, the condition that the EGR gas is flowed in a large amount according to the opening degree of the EGR valve 19 to secure the EGR temperature is set as a precondition, and the outlet side EGR gas temperature of the EGR cooler is set as the threshold value. Therefore, it is possible to easily and appropriately detect a decrease in efficiency and abnormality of the EGR cooler. Further, since the EGR gas temperature at the outlet side of the EGR cooler 17 is used, it is possible to suitably detect a decrease in efficiency or abnormality of the EGR cooler 17.

またＥＧＲガスを多量に流してＥＧＲ温度を確保する条件を前提条件とすることにより、ＥＧＲクーラ１７が劣化して効率が低下した時の出口側ＥＧＲガス温度と、ＥＧＲクーラ１７が正常である時の出口側ＥＧＲガス温度とについて温度差を生じるので、ＥＧＲクーラ１７の効率低下時と正常時とを容易に区別し、誤検出に対するロバスト性を向上することができる。ここでＥＧＲガスを多量に流してＥＧＲ温度を確保することができない場合には、正常時と異常時の区別が容易でなく、ＥＧＲクーラ１７の効率低下や異常を適切に測定することができないと共に、誤検出に対するロバスト性が低下する。   Further, by assuming that the EGR temperature is ensured by flowing a large amount of EGR gas, the outlet side EGR gas temperature when the EGR cooler 17 deteriorates and the efficiency decreases, and the EGR cooler 17 is normal. Therefore, it is possible to easily distinguish between the time when the efficiency of the EGR cooler 17 is lowered and the time when the EGR cooler 17 is normal, and to improve the robustness against erroneous detection. Here, when the EGR temperature cannot be secured by flowing a large amount of EGR gas, it is not easy to distinguish between the normal time and the abnormal time, and it is impossible to appropriately measure the efficiency reduction or abnormality of the EGR cooler 17. Robustness against false detection is reduced.

実施の形態例において、ＥＧＲクーラ１７の出口側ＥＧＲガス温度が閾値を超え、且つ閾値を超えている状態が判定基準時間以上である場合に、ＥＧＲクーラ１７に効率低下や異常があると判断するように構成すると、出口側ＥＧＲガス温度の一時的な変化でなく、ＥＧＲクーラ１７の出口側ＥＧＲガス温度を閾値と十分に比較してＥＧＲクーラ１７の効率低下や異常を適切に検出することができる。   In the embodiment, when the EGR gas temperature at the outlet side of the EGR cooler 17 exceeds the threshold and the state in which the outlet exceeds the threshold is equal to or longer than the determination reference time, it is determined that the EGR cooler 17 has a reduction in efficiency or an abnormality. With this configuration, it is possible to appropriately detect a decrease in efficiency or abnormality of the EGR cooler 17 by sufficiently comparing the outlet EGR gas temperature of the EGR cooler 17 with a threshold value instead of a temporary change in the outlet EGR gas temperature. it can.

実施の形態例において、ＥＧＲバルブ１９の開度によりＥＧＲガスを多量に流してＥＧＲ温度を確保する条件を、燃料噴射信号１４ａ（燃料の噴射量）及び回転数信号２１ａ（エンジン回転数）が所定の領域内にあることに基づいて判定するように構成すると、ＥＧＲガスを多量に流してＥＧＲ温度を確保する条件を前提条件として適切に設定し得るので、ＥＧＲクーラ１７の効率低下時と正常時とを極めて容易に区別し、ＥＧＲクーラ１７の出口側ＥＧＲガス温度を閾値と比較してＥＧＲクーラ１７の効率低下や異常を好適に検出することができると共に、誤検出に対するロバスト性を一層向上することができる。   In the embodiment, the fuel injection signal 14a (fuel injection amount) and the rotational speed signal 21a (engine rotational speed) are predetermined as conditions for ensuring the EGR temperature by flowing a large amount of EGR gas depending on the opening degree of the EGR valve 19. If the EGR cooler 17 is configured to be determined based on the fact that the EGR gas is flown in a large amount, the condition for ensuring the EGR temperature by flowing a large amount of EGR gas can be appropriately set as a precondition. And the EGR cooler 17 outlet side EGR gas temperature can be compared with a threshold value to detect a decrease in efficiency or abnormality of the EGR cooler 17 and to improve the robustness against erroneous detection. be able to.

尚、本発明の内燃機関のＥＧＲ装置は、上述の形態例にのみ限定されるものではなく、本発明の要旨を逸脱しない範囲内において種々変更を加え得ることは勿論である。   It should be noted that the EGR device for an internal combustion engine of the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the present invention.

本発明を実施する形態例を示す全体概略図である。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 本発明の実施の形態例で処理を示すフロー図である。It is a flowchart which shows a process in the embodiment of this invention. ＥＧＲガスを多量に流してＥＧＲ温度を確保する条件を概念的に示すグラフである。It is a graph which shows notionally conditions which flow EGR gas in large quantities and secure EGR temperature. 従来の内燃機関のＥＧＲ装置を示す全体概略図である。It is a whole schematic diagram showing a conventional EGR device of an internal combustion engine.

符号の説明Explanation of symbols

１ エンジン
３ 給気通路
５ 排気通路
１４ａ 燃料噴射信号（燃料の噴射量）
１６ ＥＧＲ配管
１７ ＥＧＲクーラ
１９ ＥＧＲバルブ
２１ａ 回転数信号（エンジン回転数）
２５ 制御装置 1 Engine 3 Air supply passage 5 Exhaust passage 14a Fuel injection signal (fuel injection amount)
16 EGR piping 17 EGR cooler 19 EGR valve 21a Speed signal (engine speed)
25 Control device

Claims (3)

エンジンの排気通路から給気通路へＥＧＲクーラ及びＥＧＲバルブを介してＥＧＲガスを戻すようにＥＧＲ配管を備えた内燃機関のＥＧＲ装置であって、
ＥＧＲバルブの開度によりＥＧＲガスを多量に流してＥＧＲ温度を確保する条件を前提条件とし、ＥＧＲクーラの出口側ＥＧＲガス温度を閾値と比較してＥＧＲクーラの効率低下を検出するように構成したことを特徴とする内燃機関のＥＧＲ装置。 An EGR device for an internal combustion engine provided with an EGR pipe so as to return EGR gas from an engine exhaust passage to an air supply passage via an EGR cooler and an EGR valve,
The precondition is that the EGR temperature is ensured by flowing a large amount of EGR gas depending on the opening of the EGR valve, and the EGR cooler outlet side EGR gas temperature is compared with a threshold value to detect a decrease in efficiency of the EGR cooler. An EGR device for an internal combustion engine. ＥＧＲクーラの出口側ＥＧＲガス温度が閾値を超え、且つ閾値を超えている状態が判定基準時間以上である場合に、ＥＧＲクーラに効率低下があると判断するように構成した請求項１記載の内燃機関のＥＧＲ装置。   2. The internal combustion engine according to claim 1, wherein the EGR cooler is configured to determine that the EGR cooler has a reduced efficiency when the EGR gas temperature at the outlet side of the EGR cooler exceeds a threshold value and the state where the EGR gas temperature exceeds the threshold value is equal to or longer than a determination reference time. Institutional EGR equipment. ＥＧＲバルブの開度によりＥＧＲガスを多量に流してＥＧＲ温度を確保する条件を、燃料の噴射量及びエンジン回転数が所定の領域内にあることに基づいて判定するように構成した請求項１または２記載の内燃機関のＥＧＲ装置。   2. The configuration according to claim 1, wherein a condition for securing an EGR temperature by flowing a large amount of EGR gas according to the opening of the EGR valve is determined based on the fuel injection amount and the engine speed being within a predetermined range. 3. An EGR device for an internal combustion engine according to 2.
JP2008315643A 2008-12-11 2008-12-11 Egr device for internal combustion engine Pending JP2010138788A (en)

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JP2015140667A (en) * 2014-01-27 2015-08-03 トヨタ自動車株式会社 abnormality diagnosis device
US9822739B2 (en) 2014-01-15 2017-11-21 Toyota Jidosha Kabushiki Kaisha Vehicle with an EGR-cooler and its diagnotic

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JPH08291770A (en) * 1995-04-19 1996-11-05 Fuji Heavy Ind Ltd Abnormality detecting method for exhaust gas recirculation system of engine
JP2002129996A (en) * 2000-10-25 2002-05-09 Toyota Motor Corp Exhaust emission control device for internal combustion engine
JP2003336549A (en) * 2002-05-20 2003-11-28 Denso Corp Egr device for internal combustion engine

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Publication number Priority date Publication date Assignee Title
JPH08291770A (en) * 1995-04-19 1996-11-05 Fuji Heavy Ind Ltd Abnormality detecting method for exhaust gas recirculation system of engine
JP2002129996A (en) * 2000-10-25 2002-05-09 Toyota Motor Corp Exhaust emission control device for internal combustion engine
JP2003336549A (en) * 2002-05-20 2003-11-28 Denso Corp Egr device for internal combustion engine

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014185546A (en) * 2013-03-22 2014-10-02 Toyota Motor Corp Control device of vehicle and control method
US9822739B2 (en) 2014-01-15 2017-11-21 Toyota Jidosha Kabushiki Kaisha Vehicle with an EGR-cooler and its diagnotic
JP2015140667A (en) * 2014-01-27 2015-08-03 トヨタ自動車株式会社 abnormality diagnosis device

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