JP6036207B2 - Control device for internal combustion engine - Google Patents

Control device for internal combustion engine Download PDF

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JP6036207B2
JP6036207B2 JP2012252845A JP2012252845A JP6036207B2 JP 6036207 B2 JP6036207 B2 JP 6036207B2 JP 2012252845 A JP2012252845 A JP 2012252845A JP 2012252845 A JP2012252845 A JP 2012252845A JP 6036207 B2 JP6036207 B2 JP 6036207B2
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fuel
reforming catalyst
egr
fuel reforming
reforming
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JP2014101771A (en
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耕一 芦田
耕一 芦田
堀田　勇
勇 堀田
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Nissan Motor Co 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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    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
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    • Y02T10/12—Improving ICE efficiencies

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Description

本発明は、内燃機関の制御装置に関し、特にＥＧＲ通路に介装された燃料改質触媒でＥＧＲ通路に噴射された改質用燃料の燃料改質を行う内燃機関の制御装置に関する。   The present invention relates to a control device for an internal combustion engine, and more particularly to a control device for an internal combustion engine that performs fuel reforming of reforming fuel injected into an EGR passage with a fuel reforming catalyst interposed in the EGR passage.

排気の一部を取り出し、吸気系に還流させる内燃機関のＥＧＲシステムが従来から広く知られている。   2. Description of the Related Art Conventionally, an EGR system for an internal combustion engine that extracts a part of exhaust gas and recirculates it to an intake system is widely known.

このような内燃機関のＥＧＲシステムに基づき、還流する排気（ＥＧＲガス）に改質用燃料を供給し、排気の熱を利用してＥＧＲ通路に介装された改質触媒上で改質反応させ、水素等を含む改質ガスを生成する技術が従来から広く知られている。   Based on such an EGR system of an internal combustion engine, reforming fuel is supplied to the recirculating exhaust gas (EGR gas), and the reforming reaction is performed on the reforming catalyst interposed in the EGR passage using the heat of the exhaust gas. A technique for generating a reformed gas containing hydrogen or the like has been widely known.

このような改質触媒は、ＥＧＲガス量に対して、供給される改質用燃料量が多くなると、改質触媒上に改質用燃料が付着残存し、当該改質触媒の燃料改質性能が低下する。   In such a reforming catalyst, when the amount of reforming fuel supplied increases with respect to the amount of EGR gas, the reforming fuel adheres and remains on the reforming catalyst, and the fuel reforming performance of the reforming catalyst. Decreases.

例えば、特許文献１には、このような改質触媒の燃料改質性能の低下を抑制するために、運転条件が急変した状態では、運転条件が急変していない状態に比べて、供給される改質用燃料量を少なくすることで、改質触媒上に改質用燃料が付着残存しないようにして、改質触媒の燃料改質性能の低下を抑制する技術が開示されている。   For example, in Patent Document 1, in order to suppress such a decrease in the fuel reforming performance of the reforming catalyst, it is supplied in a state where the operating condition is suddenly changed compared to a state where the operating condition is not suddenly changed. A technique is disclosed in which the amount of reforming fuel is reduced to prevent the reforming fuel from adhering and remaining on the reforming catalyst, thereby suppressing a decrease in fuel reforming performance of the reforming catalyst.

特開２００９−１６２０５３号公報JP 2009-162053 A

しかしながら、この特許文献１に開示される技術は、改質触媒の燃料改質性能の低下を抑制するものであり、一度低下してしまった改質触媒の燃料改質性能を再生（回復）させることはできないという問題がある。   However, the technique disclosed in Patent Document 1 suppresses the deterioration of the fuel reforming performance of the reforming catalyst, and regenerates (recovers) the fuel reforming performance of the reforming catalyst once reduced. There is a problem that you can't.

そこで、本発明は、ＥＧＲ通路に介装された燃料改質触媒の改質ガス生成能力が低下すると、上記燃料改質触媒の第１の再生処理として、上記燃料改質触媒の温度が所定温度以上で、かつ内燃機関への燃料供給を停止する燃料カット時に、ＥＧＲ制御弁を開弁して上記燃料改質触媒へ所定量の空気を供給することを特徴としている。そして、上記第１の再生処理を行っても、上記燃料改質触媒の改質ガス生成能力が低下している場合には、上記燃料改質触媒の第２の再生処理として、上記燃料改質触媒の温度が所定温度以上で、かつ上記内燃機関への燃料供給を停止する燃料カット時に、上記ＥＧＲ制御弁を開弁して上記燃料改質触媒へ空気を供給すると共に、上記改質用燃料噴射弁から上記改質用燃料を噴射して上記燃料改質触媒に所定量の上記改質用燃料を供給する。また、上記第２の再生処理の開始時における上記燃料改質触媒の温度が低いほど、上記第２の再生処理期間中に上記燃料改質触媒に供給される空気量及び改質用燃料量が多くなるように設定されている。
Therefore, according to the present invention, when the reformed gas generation capacity of the fuel reforming catalyst interposed in the EGR passage decreases, the temperature of the fuel reforming catalyst is set to a predetermined temperature as the first regeneration process of the fuel reforming catalyst. As described above, when the fuel is cut to stop the fuel supply to the internal combustion engine, the EGR control valve is opened to supply a predetermined amount of air to the fuel reforming catalyst. If the reformed gas generation capacity of the fuel reforming catalyst is lowered even after the first regeneration process, the fuel reforming process is performed as the second regeneration process of the fuel reforming catalyst. When the temperature of the catalyst is equal to or higher than a predetermined temperature and the fuel is cut to stop the fuel supply to the internal combustion engine, the EGR control valve is opened to supply air to the fuel reforming catalyst, and the reforming fuel The reforming fuel is injected from the injection valve, and a predetermined amount of the reforming fuel is supplied to the fuel reforming catalyst. Further, the lower the temperature of the fuel reforming catalyst at the start of the second regeneration process, the more the amount of air and the amount of reforming fuel supplied to the fuel reforming catalyst during the second regeneration process period. It is set to increase.

本発明によれば、燃料改質触媒の性能低下の要因となる触媒毒（硫黄被毒）や煤を燃焼除去することが可能となり、燃料改質触媒の燃料改質性能を再生（回復）させることができる。   According to the present invention, it becomes possible to burn and remove the catalyst poison (sulfur poisoning) and soot that cause a reduction in the performance of the fuel reforming catalyst, and to regenerate (recover) the fuel reforming performance of the fuel reforming catalyst. be able to.

本発明が適用される内燃機関のシステム構成の概略を模式的に示した説明図。BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which showed typically the outline of the system configuration | structure of the internal combustion engine to which this invention is applied. 本発明に係る内燃機関の制御装置の制御の流れの一例を示すフローチャート。The flowchart which shows an example of the flow of control of the control apparatus of the internal combustion engine which concerns on this invention.

以下、本発明の一実施例を図面に基づいて詳細に説明する。図１は、本発明が適用される内燃機関のシステム構成の概略を模式的に示した説明図である。   Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory view schematically showing an outline of a system configuration of an internal combustion engine to which the present invention is applied.

内燃機関１は、駆動源として自動車等の車両に搭載されるものであって、吸気通路２と排気通路３とが接続されている。吸気通路２には、スロットル弁４が設けられている。スロットル弁４の下流側には、燃料タンク６から供給された燃料を吸気通路２内に噴射する燃料噴射弁７が設けられている。また、スロットル弁４の上流側には、吸入空気量を検出するエアフローメータ８が設けられている。   The internal combustion engine 1 is mounted on a vehicle such as an automobile as a drive source, and an intake passage 2 and an exhaust passage 3 are connected to each other. A throttle valve 4 is provided in the intake passage 2. A fuel injection valve 7 for injecting fuel supplied from the fuel tank 6 into the intake passage 2 is provided on the downstream side of the throttle valve 4. An air flow meter 8 for detecting the intake air amount is provided on the upstream side of the throttle valve 4.

排気通路３には、三元触媒等の排気触媒９が設けられている。この排気触媒９の上流側には、内燃機関１から排出された排気の空燃比を検出する空燃比センサ１０が設けられている。この空燃比センサ１０は、空燃比に応じたほぼリニアな出力特性を有するものである。また、排気触媒９の下流側には、空燃比のリッチ、リーンのみを検出する酸素センサ１１が設けられている。   An exhaust catalyst 9 such as a three-way catalyst is provided in the exhaust passage 3. An air-fuel ratio sensor 10 that detects the air-fuel ratio of the exhaust discharged from the internal combustion engine 1 is provided on the upstream side of the exhaust catalyst 9. The air-fuel ratio sensor 10 has a substantially linear output characteristic corresponding to the air-fuel ratio. Further, an oxygen sensor 11 that detects only the rich and lean air-fuel ratio is provided on the downstream side of the exhaust catalyst 9.

内燃機関１は、排気還流（ＥＧＲ）が実施可能なものであって、排気通路３と吸気通路２との間には、ＥＧＲ通路１２が設けられている。ＥＧＲ通路１２は、その一端が排気触媒９の上流側の位置で排気通路３に接続され、その他端がスロットル弁４の下流側となる位置で吸気通路２に接続されている。そして、このＥＧＲ通路１２には、排気通路３側から順に、ＥＧＲ制御弁１３、改質用燃料噴射弁１４、燃料蒸発器１５、燃料改質触媒１６、ＥＧＲクーラ１７が設けられている。   The internal combustion engine 1 can perform exhaust gas recirculation (EGR), and an EGR passage 12 is provided between the exhaust passage 3 and the intake passage 2. One end of the EGR passage 12 is connected to the exhaust passage 3 at a position upstream of the exhaust catalyst 9, and the other end is connected to the intake passage 2 at a position downstream of the throttle valve 4. The EGR passage 12 is provided with an EGR control valve 13, a reforming fuel injection valve 14, a fuel evaporator 15, a fuel reforming catalyst 16, and an EGR cooler 17 in this order from the exhaust passage 3 side.

ＥＧＲ制御弁１３の弁開度は、運転条件に応じた所定のＥＧＲ率が得られるように、ＥＣＵ（エンジンコントロールユニット）１８によって制御される。   The valve opening degree of the EGR control valve 13 is controlled by an ECU (Engine Control Unit) 18 so that a predetermined EGR rate corresponding to the operating condition is obtained.

改質用燃料噴射弁１４は、燃料タンク６から供給された燃料を改質用燃料としてＥＧＲ通路１２内に噴射するものである。上記改質用燃料は、燃料蒸発器１５で気化され、ＥＧＲ通路１２に導入された排気（ＥＧＲガス）とともに燃料改質触媒１６に供給される。   The reforming fuel injection valve 14 injects the fuel supplied from the fuel tank 6 into the EGR passage 12 as reforming fuel. The reforming fuel is vaporized by the fuel evaporator 15 and supplied to the fuel reforming catalyst 16 together with the exhaust gas (EGR gas) introduced into the EGR passage 12.

燃料改質触媒１６は、例えばコージェライトからなるハニカム担体に、ロジウムを担持させたものであって、ＥＧＲ通路１２に導入された排気（ＥＧＲガス）と上記改質用燃料とを用いて水素を生成可能なものである。つまり、燃料改質触媒１６は、ＥＧＲ実施中に、改質用燃料噴射弁１４から上記改質用燃料が噴射されると、ＥＧＲガスと上記改質用燃料から水素を含んだ改質ガスを生成する。この燃料改質触媒１６の温度は、温度センサ１９によって検出される。   The fuel reforming catalyst 16 is one in which rhodium is supported on a honeycomb carrier made of, for example, cordierite, and hydrogen is generated using the exhaust gas (EGR gas) introduced into the EGR passage 12 and the reforming fuel. It can be generated. That is, when the reforming fuel is injected from the reforming fuel injection valve 14 during the EGR, the fuel reforming catalyst 16 generates the reformed gas containing hydrogen from the EGR gas and the reforming fuel. Generate. The temperature of the fuel reforming catalyst 16 is detected by a temperature sensor 19.

ＥＧＲクーラ１７は、燃料改質触媒１６よりも吸気通路２側（下流側）に位置し、ＥＧＲガス及び改質ガスを冷却する。   The EGR cooler 17 is located closer to the intake passage 2 (downstream side) than the fuel reforming catalyst 16 and cools the EGR gas and the reformed gas.

改質ガスに含まれる水素の濃度は、吸気通路２に配置された水素センサ２０によって検出される。この水素センサ２０は、吸気通路２のＥＧＲ通路１２他端が接続された位置よりも下流側に位置している。   The concentration of hydrogen contained in the reformed gas is detected by a hydrogen sensor 20 disposed in the intake passage 2. The hydrogen sensor 20 is located downstream of the position where the other end of the EGR passage 12 of the intake passage 2 is connected.

なお、図１中の２１は、ＥＧＲ制御弁１３と改質用燃料噴射弁１４との間に設けられ、ＥＧＲ通路１２に導入された排気（ＥＧＲガス）の温度を検出するＥＧＲガス温度センサ、図１中の２２は、ＥＧＲクーラ１７とＥＧＲ通路１２他端との間に設けられ、空燃比のリッチ、リーンのみを検出する酸素センサである。   1 is an EGR gas temperature sensor that is provided between the EGR control valve 13 and the reforming fuel injection valve 14, and detects the temperature of exhaust gas (EGR gas) introduced into the EGR passage 12. Reference numeral 22 in FIG. 1 denotes an oxygen sensor that is provided between the EGR cooler 17 and the other end of the EGR passage 12 and detects only the rich and lean air-fuel ratio.

ＥＣＵ１８には、上述したエアフローメータ８、空燃比センサ１０、酸素センサ１１、２２、排気ガス温度センサ２１、水素センサ２０からの検出信号のほか、クランクシャフト（図示せず）のクランク角を検出するクランク角センサ２３、アクセルペダル（図示せず）の踏込量を検出するアクセル開度センサ２４、車速を検出する車速センサ２５等、各種センサ類の検出信号が入力されている。   The ECU 18 detects a crank angle of a crankshaft (not shown) in addition to detection signals from the air flow meter 8, the air-fuel ratio sensor 10, the oxygen sensors 11 and 22, the exhaust gas temperature sensor 21, and the hydrogen sensor 20. Detection signals of various sensors such as a crank angle sensor 23, an accelerator opening sensor 24 that detects the amount of depression of an accelerator pedal (not shown), a vehicle speed sensor 25 that detects a vehicle speed, and the like are input.

ＥＣＵ１８は、マイクロコンピュータを内蔵し、内燃機関１の種々の制御を行うものであって、運転状態に応じてＥＧＲ量（排気還流量）を制御するＥＧＲ制御のほかに、アクセル開度に応じたスロットル弁４の開度や、運転状態に応じた燃料噴射弁７からの燃料噴射量や、改質用燃料噴射弁１４からの改質用燃料の噴射量等、内燃機関１の各種制御を行っている。   The ECU 18 incorporates a microcomputer and performs various controls of the internal combustion engine 1. In addition to the EGR control that controls the EGR amount (exhaust gas recirculation amount) according to the operating state, the ECU 18 corresponds to the accelerator opening. Various controls of the internal combustion engine 1 such as the opening degree of the throttle valve 4, the fuel injection amount from the fuel injection valve 7 according to the operating state, and the reforming fuel injection amount from the reforming fuel injection valve 14 are performed. ing.

ここで、燃料改質触媒１６の燃料改質性能の低下が、硫黄被毒等の触媒毒や煤の付着の場合、これらを燃焼除去することで、燃料改質触媒１６の燃料改質性能を再生（回復）させることが可能である。そこで、ＥＧＲ実施中に改質用燃料を燃料改質触媒１６に供給しても水素センサ２０で検出される燃料改質触媒１６下流側の水素濃度が所定濃度以上とはならない場合に、燃料改質触媒１６の燃料改質性能を再生させる処理が必要であると判定し、燃料改質触媒１６から触媒毒（硫黄被毒）や煤を燃焼除去する。   Here, when the fuel reforming performance of the fuel reforming catalyst 16 is deteriorated due to catalyst poisoning such as sulfur poisoning or soot adhesion, the fuel reforming performance of the fuel reforming catalyst 16 is improved by removing these by combustion. It is possible to regenerate (recover). Therefore, if the hydrogen concentration on the downstream side of the fuel reforming catalyst 16 detected by the hydrogen sensor 20 does not exceed the predetermined concentration even if the reforming fuel is supplied to the fuel reforming catalyst 16 during EGR, the fuel reforming is performed. It is determined that a process for regenerating the fuel reforming performance of the catalyst 16 is necessary, and catalyst poison (sulfur poisoning) and soot are burned and removed from the fuel reforming catalyst 16.

燃料改質触媒１６から触媒毒（硫黄被毒）や煤を燃焼除去する場合には、燃料改質触媒１６に対し酸素（空気）を供給して燃焼を促す必要があるが、排気空燃比がリーンとなるように燃焼制御して燃料改質触媒１６に酸素を供給すると、排気エミッションが悪化する虞がある。また、排気通路３あるいはＥＧＲ通路１２に空気を導入可能ないわゆる２次エア供給用の構成を設ければ、排気空燃比がリーンとなるように燃焼制御しなくても燃料改質触媒１６に酸素を供給することは可能となるが、２次エア供給用の構成を設ける分、コストが高くなると共に、システム全体が大型化してしまう。   When removing catalyst poison (sulfur poisoning) or soot from the fuel reforming catalyst 16, it is necessary to supply oxygen (air) to the fuel reforming catalyst 16 to promote combustion. If oxygen is supplied to the fuel reforming catalyst 16 by controlling combustion so as to be lean, there is a possibility that exhaust emission may deteriorate. Further, if a so-called secondary air supply structure capable of introducing air into the exhaust passage 3 or the EGR passage 12 is provided, the fuel reforming catalyst 16 is supplied with oxygen without performing combustion control so that the exhaust air-fuel ratio becomes lean. However, as the secondary air supply structure is provided, the cost increases and the entire system increases in size.

そこで、本実施例では、燃料改質触媒１６の再生処理が必要と判定されると、燃料改質触媒１６が所定温度以上で、かつ内燃機関１への燃料供給を停止する所定の燃料カット運転時に、ＥＧＲ制御弁１３を開いて空気を燃料改質触媒１６に供給する第１再生モード（第１の再生処理）を実施する。ここで、上記所定温度は、例えば、空気を供給すれば酸化反応が生じる燃料改質触媒１６の最低反応温度であり、後述する再生可能目標温度よりも低い温度である。つまり、燃料改質触媒１６に空気を供給しても、燃料改質触媒１６の温度が低すぎて燃料改質触媒１６上で酸化反応が生じないことがないように、上記所定温度は設定される。   Therefore, in this embodiment, when it is determined that the regeneration process of the fuel reforming catalyst 16 is necessary, the fuel reforming catalyst 16 is at a predetermined temperature or higher and the predetermined fuel cut operation for stopping the fuel supply to the internal combustion engine 1 is performed. Sometimes, the first regeneration mode (first regeneration process) is performed in which the EGR control valve 13 is opened and air is supplied to the fuel reforming catalyst 16. Here, the predetermined temperature is, for example, the lowest reaction temperature of the fuel reforming catalyst 16 that undergoes an oxidation reaction when air is supplied, and is a temperature lower than a reproducible target temperature described later. That is, the predetermined temperature is set so that even if air is supplied to the fuel reforming catalyst 16, the temperature of the fuel reforming catalyst 16 is not too low to cause an oxidation reaction on the fuel reforming catalyst 16. The

なお、燃料カット運転は、例えば、アクセル開度が所定開度以下で、機関回転数が所定の燃料カット回転数以上で、かつ車速が所定の燃料カット速度以上のときに実施される。そして、上記燃料カット運転中に、例えば、アクセル開度が上記所定開度より大きい、機関回転数が所定の燃料カットリカバー回転数よりも低い、車速が所定の燃料カットリカバー速度よりも低い、のいずれかの条件が満たされたときに、上記燃料カット運転は終了する。   The fuel cut operation is performed, for example, when the accelerator opening is equal to or less than a predetermined opening, the engine speed is equal to or higher than a predetermined fuel cut speed, and the vehicle speed is equal to or higher than a predetermined fuel cut speed. During the fuel cut operation, for example, the accelerator opening is larger than the predetermined opening, the engine speed is lower than the predetermined fuel cut recovery speed, and the vehicle speed is lower than the predetermined fuel cut recovery speed. When any of the conditions is satisfied, the fuel cut operation ends.

これによって、燃料改質触媒１６に酸化反応を促進させる空気を供給することができ、触媒毒（硫黄被毒）や煤を燃焼除去することが可能となって、燃料改質触媒１６の燃料改質性能を再生（回復）させることができる。   As a result, air that promotes the oxidation reaction can be supplied to the fuel reforming catalyst 16, and catalyst poison (sulfur poisoning) and soot can be burned and removed. Quality performance can be regenerated (recovered).

また、燃料改質触媒１６の燃料改質性能を適宜再生させることができるので、燃料改質性能の低下を見込んで燃料改質触媒１６のサイズを予め大きめに設定しておく必要もなく、その分燃料改質触媒１６を小型化することができる。   In addition, since the fuel reforming performance of the fuel reforming catalyst 16 can be regenerated as appropriate, it is not necessary to set the size of the fuel reforming catalyst 16 in advance in view of a decrease in the fuel reforming performance. The minute fuel reforming catalyst 16 can be reduced in size.

第１再生モードでは、第１再生モードを開始する際の燃料改質触媒１６の温度と、燃料改質触媒１６の触媒毒（硫黄被毒）や煤が燃焼除去される温度である再生可能目標温度との温度差に応じて必要空気量を算出する。そして、算出された上記必要空気量が燃料改質触媒１６の供給されるようにＥＧＲ制御弁１３の開弁期間、弁開度、開弁開始時期を算出し、ＥＧＲ制御弁１３を制御する。   In the first regeneration mode, the temperature of the fuel reforming catalyst 16 at the time of starting the first regeneration mode and the regeneration target that is the temperature at which the catalyst poison (sulfur poisoning) and soot of the fuel reforming catalyst 16 are burned and removed. The required air amount is calculated according to the temperature difference from the temperature. Then, the valve opening period, the valve opening degree, and the valve opening start timing of the EGR control valve 13 are calculated so that the calculated required air amount is supplied to the fuel reforming catalyst 16, and the EGR control valve 13 is controlled.

上記必要空気量は、燃料改質触媒１６上に燃焼可能な物質（例えば煤）があるものとした場合、燃料改質触媒１６が酸化反応（燃焼）により上記再生可能目標温度に達するのに必要な空気量である。つまり、燃料改質触媒１６の温度と上記再生可能目標温度との温度差が大きくなるほど、換言すれば燃料改質触媒１６の温度が低くなるほど、上記必要空気量は多くなるように設定される。例えば、燃料改質触媒１６の温度と上記再生可能目温度との温度差に対応する必要空気量を予め実験等で求めてマップ化しておけば、マップ参照により上記必要空気量を算出可能である。   The required air amount is necessary for the fuel reforming catalyst 16 to reach the renewable target temperature by an oxidation reaction (combustion) when there is a combustible substance (for example, soot) on the fuel reforming catalyst 16. Air volume. In other words, the required air amount is set to increase as the temperature difference between the temperature of the fuel reforming catalyst 16 and the renewable target temperature increases, in other words, as the temperature of the fuel reforming catalyst 16 decreases. For example, if the required air amount corresponding to the temperature difference between the temperature of the fuel reforming catalyst 16 and the regenerative eye temperature is obtained in advance through experiments or the like and mapped, the required air amount can be calculated by referring to the map. .

このように、第１再生モードでは、燃料改質触媒１６の温度に応じた量の空気が供給されることになるので、必要以上の空気が供給され、燃料改質触媒１６が過度に高温となり、高温劣化してしまうことを抑制することができる。   Thus, in the first regeneration mode, an amount of air corresponding to the temperature of the fuel reforming catalyst 16 is supplied, so that more air than necessary is supplied and the fuel reforming catalyst 16 becomes excessively hot. It is possible to suppress deterioration at high temperatures.

そして、上記必要空気量を燃料改質触媒１６に供給する際のＥＧＲ制御弁１３の開弁期間や弁開度は、当該必要空気量とそのときの機関回転数に応じた最適な組み合わせを予め実験等により算出しておくものとする。本実施例では、上記必要空気量と機関回転数からマップ参照により第１再生モード時のＥＧＲ制御弁１３の開弁期間や弁開度が算出される。第１再生モードにおいて、上記必要空気量が多くなるほど、ＥＧＲ制御弁１３の開弁期間は相対的に長くなり、ＥＧＲ制御弁１３の弁開度は相対的に大きくなるよう設定されている。   The valve opening period and valve opening of the EGR control valve 13 when supplying the required air amount to the fuel reforming catalyst 16 are previously set to an optimum combination according to the required air amount and the engine speed at that time. It shall be calculated by experiment etc. In the present embodiment, the valve opening period and the valve opening degree of the EGR control valve 13 in the first regeneration mode are calculated by referring to the map from the required air amount and the engine speed. In the first regeneration mode, the EGR control valve 13 is set so that the valve opening period of the EGR control valve 13 becomes relatively longer and the valve opening degree of the EGR control valve 13 becomes relatively larger as the required air amount increases.

また、第１再生モード時におけるＥＧＲ制御弁１３の開弁開始時期は、上記燃料カット運転の開始時期を基準として決定されたものであり、機関回転数に応じて予め実験等により算出しておくものとする。本実施例では、機関回転数からマップ参照により第１再生モード時のＥＧＲ制御弁１３の開弁開始期間が算出される。この開弁開始時期は、上記燃料カット運転が実施されて直後では、排気通路３に上記燃料カット運転開始前の排気が残っていることを事を考慮したものであって、ＥＧＲ制御弁１３を開弁すると空気がＥＧＲ通路１２に導入されるタイミングとなるように設定されている。燃料噴射弁７から燃料が噴射される位置からＥＧＲ通路１２と排気通路３との接続位置までの吸排気系の容積が決まれば、機関回転数に応じて上記開弁開始時期を算出可能となる。つまり第１再生モードにおけるＥＧＲ制御弁１３の開弁開始時期は、上記燃料カット運転が開始されてから所定時間が経過したタイミングであり、機関回転数が高くなるほど、相対的に早くなる（上記燃料カット運転開始時期に近づく）よう設定されている。   Further, the opening start timing of the EGR control valve 13 in the first regeneration mode is determined based on the start timing of the fuel cut operation, and is calculated in advance by experiments or the like according to the engine speed. Shall. In this embodiment, the valve opening start period of the EGR control valve 13 in the first regeneration mode is calculated from the engine speed by referring to the map. This valve opening start time is taken into consideration that the exhaust before the start of the fuel cut operation remains in the exhaust passage 3 immediately after the fuel cut operation is performed, and the EGR control valve 13 is turned on. It is set so that when the valve is opened, it is time to introduce air into the EGR passage 12. If the volume of the intake / exhaust system from the position at which fuel is injected from the fuel injection valve 7 to the connection position between the EGR passage 12 and the exhaust passage 3 is determined, the valve opening start timing can be calculated according to the engine speed. . That is, the opening start timing of the EGR control valve 13 in the first regeneration mode is a timing at which a predetermined time has elapsed after the fuel cut operation is started, and becomes relatively earlier as the engine speed increases (the fuel It is set to approach the cutting operation start time).

このように、ＥＧＲ制御弁１３を制御することで上記必要空気量を燃料改質触媒１６に供給することが可能であり、第１再生モードを実施するにあたって、新たな構成要素を追加する必要はない。   As described above, it is possible to supply the required amount of air to the fuel reforming catalyst 16 by controlling the EGR control valve 13, and it is necessary to add a new component when performing the first regeneration mode. Absent.

上記燃料カット運転中にＥＧＲ制御弁１３を開いて空気を導入するだけの上記第１再生モードで燃料改質触媒１６の再生が不十分な場合には、第２再生モード（第２の再生処理）による燃料改質触媒１６の再生を実施する。本実施例では、上記第１再生モードを実施した結果、燃料改質触媒１６の温度が上記再生可能目標温度に達しない場合、空気だけでは触媒毒（硫黄被毒）や煤を除去できるだけの燃焼が発生せず、燃料改質触媒１６の再生が不十分と判定する。   When regeneration of the fuel reforming catalyst 16 is insufficient in the first regeneration mode in which the EGR control valve 13 is opened and air is introduced during the fuel cut operation, the second regeneration mode (second regeneration process) The fuel reforming catalyst 16 is regenerated by (1). In this embodiment, when the temperature of the fuel reforming catalyst 16 does not reach the reproducible target temperature as a result of performing the first regeneration mode, combustion that can remove catalyst poison (sulfur poisoning) and soot with air alone is performed. Therefore, it is determined that regeneration of the fuel reforming catalyst 16 is insufficient.

第２再生モードでは、上記燃料カット運転時に、ＥＧＲ制御弁１３を開いて空気を導入すると共に、改質用燃料噴射弁１４から改質用燃料を噴射する。   In the second regeneration mode, the EGR control valve 13 is opened to introduce air and the reforming fuel is injected from the reforming fuel injection valve 14 during the fuel cut operation.

これにより燃料改質触媒１６には、上記燃料カット運転時に酸素及び改質用燃料が供給され、触媒毒（硫黄被毒）や煤を燃焼除去するに足る酸化反応（燃焼）を燃料改質触媒上で確実に実現することができ、燃料改質触媒１６の燃料改質性能を再生（回復）させることができる。   As a result, oxygen and reforming fuel are supplied to the fuel reforming catalyst 16 during the fuel cut operation, and an oxidation reaction (combustion) sufficient to burn and remove the catalyst poison (sulfur poisoning) and soot is the fuel reforming catalyst. Thus, the fuel reforming performance of the fuel reforming catalyst 16 can be regenerated (recovered).

第２再生モードでは、第２再生モードを開始する際の燃料改質触媒１６の温度と、燃料改質触媒１６の触媒毒（硫黄被毒）や煤が燃焼除去される温度である上記再生可能目標温度との温度差に応じて必要空気量及び必要改質用燃料量を算出する。第２再生モードにおける必要空気量及び必要改質用燃料量は、燃料改質触媒１６上に燃焼可能な物質がないものとして、燃料改質触媒１６が酸化反応（燃焼）により上記再生可能目標温度に達するのに必要な量である。なお、本実施例では、第２再生モードの必要空気量と第１再生モードにおける必要空気量とは、同様の方法で算出される。従って、燃料改質触媒１６の温度と上記再生可能目標温度との温度差が大きくなるほど、換言すれば燃料改質触媒１６の温度が低くなるほど、第２再生モードで算出された必要空気量と上記必要改質用燃料量は多くなるように設定される。   In the second regeneration mode, the temperature of the fuel reforming catalyst 16 at the start of the second regeneration mode and the temperature at which the catalyst poison (sulfur poisoning) and soot of the fuel reforming catalyst 16 are combusted and removed can be regenerated. The required air amount and the required reforming fuel amount are calculated according to the temperature difference from the target temperature. The required air amount and the required reforming fuel amount in the second regeneration mode assume that there is no combustible substance on the fuel reforming catalyst 16, and the fuel reforming catalyst 16 is subjected to the above-described reproducible target temperature by oxidation reaction (combustion) Is the amount needed to reach In the present embodiment, the required air amount in the second regeneration mode and the required air amount in the first regeneration mode are calculated by the same method. Accordingly, as the temperature difference between the temperature of the fuel reforming catalyst 16 and the reproducible target temperature becomes larger, in other words, as the temperature of the fuel reforming catalyst 16 becomes lower, the required air amount calculated in the second regeneration mode and the above-mentioned The required amount of reforming fuel is set to be large.

このように、第２再生モードでは、燃料改質触媒１６の温度に応じた量の空気及び燃料が当該燃料改質触媒１６に供給されることになるので、必要以上の空気及び燃料が燃料改質触媒１６に供給され、燃料改質触媒１６が過度に高温となり、高温劣化してしまうことを抑制することができる。   In this way, in the second regeneration mode, air and fuel in an amount corresponding to the temperature of the fuel reforming catalyst 16 are supplied to the fuel reforming catalyst 16, so that more air and fuel than necessary are required for fuel reform. It is possible to suppress the fuel reforming catalyst 16 from being excessively heated to a high temperature and being deteriorated at a high temperature.

第２再生モードにおけるＥＧＲ制御弁１３の開弁期間及び弁開度は、第２再生モードで算出された必要空気量と機関回転数からマップ参照により算出される。第２再生モードにおいても、上記必要空気量が多くなるほど、ＥＧＲ制御弁１３の開弁期間は相対的に長くなり、ＥＧＲ制御弁１３の弁開度は相対的に大きくなるよう設定されている。なお、第２再生モードは、第１再生モードに引き続き実施されるので、第１再生モードのようにＥＧＲ制御弁１３の開弁開始時期を算出する必要はない。また、本実施例では、第１再生モードで使用したマップを利用して、第２再生モードにおけるＥＧＲ制御弁１３の開弁期間及び弁開度を算出している。   The valve opening period and the valve opening of the EGR control valve 13 in the second regeneration mode are calculated by referring to the map from the necessary air amount and the engine speed calculated in the second regeneration mode. Also in the second regeneration mode, the valve opening period of the EGR control valve 13 is set to be relatively long and the valve opening degree of the EGR control valve 13 is set to be relatively large as the required air amount increases. Note that since the second regeneration mode is carried out following the first regeneration mode, it is not necessary to calculate the opening start timing of the EGR control valve 13 as in the first regeneration mode. In this embodiment, the opening period and the valve opening of the EGR control valve 13 in the second regeneration mode are calculated using the map used in the first regeneration mode.

上記必要改質用燃料量を燃料改質触媒１６に供給する際の改質用燃料噴射弁１４の噴射期間や噴射開始時期は、当該必要改質用燃料量とそのときの機関回転数に応じた最適な組み合わせを予め実験等により算出しておくものとする。本実施例では、上記必要改質用燃料量と機関回転数からマップ参照により第２再生モード時の改質用燃料噴射弁１４の噴射期間や噴射開始時期が算出される。第２再生モードにおいて、上記必要改質用燃料量が多くなるほど、改質用燃料噴射弁１４の噴射期間は相対的に長くなる。また、第２再生モードにおいて、機関回転数が高くなるほど、改質用燃料噴射弁１４の噴射開始時期は相対的に早くなるよう設定されている。   The injection period and injection start timing of the reforming fuel injection valve 14 when supplying the necessary reforming fuel amount to the fuel reforming catalyst 16 depend on the necessary reforming fuel amount and the engine speed at that time. It is assumed that the optimum combination is calculated in advance by experiments or the like. In the present embodiment, the injection period and the injection start timing of the reforming fuel injection valve 14 in the second regeneration mode are calculated by referring to the map from the required reforming fuel amount and the engine speed. In the second regeneration mode, the injection period of the reforming fuel injection valve 14 becomes relatively longer as the required reforming fuel amount increases. In the second regeneration mode, the injection start timing of the reforming fuel injection valve 14 is set to be relatively earlier as the engine speed increases.

つまり、ＥＧＲ制御弁１３及び改質用燃料噴射弁１４を制御することで上記必要空気量及び上記必要改質用燃料量を燃料改質触媒１６に供給することが可能であり、第２再生モードを実施するにあたって、新たな構成要素を追加する必要はない。   That is, the required air amount and the required reforming fuel amount can be supplied to the fuel reforming catalyst 16 by controlling the EGR control valve 13 and the reforming fuel injection valve 14, and the second regeneration mode. There is no need to add new components to implement

また、第２再生モードの終了後に、燃料改質触媒１６の再生が不十分な場合には、再度、第２再生モードによる燃料改質触媒１６の再生を実施するようにしてもよい。   Further, when the regeneration of the fuel reforming catalyst 16 is insufficient after the end of the second regeneration mode, the regeneration of the fuel reforming catalyst 16 in the second regeneration mode may be performed again.

図２は、上述した本実施例の制御の流れを示すフローチャートである。Ｓ１では、燃料改質触媒１６に再生処理が必要か否かを判定する。本実施例では、改質用燃料を燃料改質触媒１６に供給しても水素センサ２０により検出される水素濃度が所定濃度未満のときに、燃料改質触媒１６に再生処理が必要と判定し、Ｓ２へ進む。Ｓ２では、燃料改質触媒１６の温度が上記所定温度以上であるか否かを判定し、上記所定温度以上であればＳ３へ進み、そうでなければ今回のルーチンを終了する。Ｓ３では、現在の運転状態が上記燃料カット運転であるか否かを判定し、燃料カット運転中であればＳ４へ進み、そうでなければ今回のルーチンを終了する。Ｓ４では、燃料改質触媒１６の温度と上記再生可能目標温度から上記必要空気量を算出する。Ｓ５では、ＥＧＲ制御弁１３の開弁期間、弁開度、開弁開始時期を、機関回転数とＳ４で算出された必要空気量を用い、それぞれ対応するマップから算出する。Ｓ６では、Ｓ５で算出された条件でＥＧＲ制御弁１３を制御する第１再生モードを実施する。すなわち、本実施例においては、必要空気量からＥＧＲ制御弁１３の開弁期間、弁開度、開弁開始時期が算出されると、直ちに第１再生モードが開始される。Ｓ７では、Ｓ４で算出された必要空気量が燃料改質触媒１６に供給されると第１再生モードが終了した判定する。第１再生モードが終了した場合には、ＥＧＲ制御弁１３を閉弁し、Ｓ８へ進む。   FIG. 2 is a flowchart showing the control flow of the present embodiment described above. In S1, it is determined whether the fuel reforming catalyst 16 needs to be regenerated. In this embodiment, even if the reforming fuel is supplied to the fuel reforming catalyst 16, it is determined that the fuel reforming catalyst 16 needs to be regenerated when the hydrogen concentration detected by the hydrogen sensor 20 is less than a predetermined concentration. , Go to S2. In S2, it is determined whether or not the temperature of the fuel reforming catalyst 16 is equal to or higher than the predetermined temperature. If the temperature is equal to or higher than the predetermined temperature, the process proceeds to S3. Otherwise, the current routine is terminated. In S3, it is determined whether or not the current operation state is the fuel cut operation. If the fuel cut operation is being performed, the process proceeds to S4, and if not, the current routine is terminated. In S4, the required air amount is calculated from the temperature of the fuel reforming catalyst 16 and the reproducible target temperature. In S5, the valve opening period, the valve opening degree, and the valve opening start timing of the EGR control valve 13 are calculated from the corresponding maps using the engine speed and the necessary air amount calculated in S4. In S6, the first regeneration mode for controlling the EGR control valve 13 under the conditions calculated in S5 is performed. That is, in the present embodiment, the first regeneration mode is immediately started when the valve opening period, the valve opening degree, and the valve opening start timing of the EGR control valve 13 are calculated from the required air amount. In S7, when the required air amount calculated in S4 is supplied to the fuel reforming catalyst 16, it is determined that the first regeneration mode has ended. When the first regeneration mode is completed, the EGR control valve 13 is closed and the process proceeds to S8.

Ｓ８では、燃料改質触媒１６の温度が上記再生可能目標温度以上になっているか否かを判定する。燃料改質触媒１６の温度が上記再生可能目標温度以上であれば、燃料改質触媒１６上の触媒毒（硫黄被毒）や煤が燃焼により除去されたものと見なして、今回のルーティンを終了する。一方、燃料改質触媒１６の温度が上記再生可能目標温度に達していない場合には、Ｓ９へ進む。   In S8, it is determined whether or not the temperature of the fuel reforming catalyst 16 is equal to or higher than the renewable target temperature. If the temperature of the fuel reforming catalyst 16 is equal to or higher than the reproducible target temperature, it is assumed that the catalyst poison (sulfur poisoning) and soot on the fuel reforming catalyst 16 have been removed by combustion, and the current routine is finished. To do. On the other hand, if the temperature of the fuel reforming catalyst 16 has not reached the reproducible target temperature, the process proceeds to S9.

Ｓ９では、現在の運転状態が上記燃料カット運転であるか否かを判定し、燃料カット運転中であればＳ１０へ進み、そうでなければ今回のルーチンを終了する。Ｓ１０では、燃料改質触媒１６の温度と上記再生可能目標温度から上記必要空気量を算出する。Ｓ１１では、ＥＧＲ制御弁１３の開弁期間、弁開度、開弁開始時期を、機関回転数とＳ１０で算出された必要空気量を用い、それぞれ対応するマップから算出する。Ｓ１２では、燃料改質触媒１６の温度と上記再生可能目標温度から上記必要改質用燃料量を算出する。Ｓ１３では、改質用燃料噴射弁１４の燃料噴射期間、燃料噴射開始時期を、機関回転数とＳ１２で算出された必要改質用燃料量を用い、それぞれ対応するマップから算出する。Ｓ１４では、Ｓ１１及びＳ１３で算出された条件でＥＧＲ制御弁１３及び改質用燃料噴射弁１４を制御する第２再生モードを実施する。すなわち、第１再生モードでは燃料改質触媒１６の再生が不十分な場合、上記燃料カット運転が継続されていれば、空気と燃料の双方を燃料改質触媒１６に供給する第２再生モードが直ちに実施される。   In S9, it is determined whether or not the current operation state is the fuel cut operation. If the fuel cut operation is being performed, the process proceeds to S10, and if not, the current routine is terminated. In S10, the required air amount is calculated from the temperature of the fuel reforming catalyst 16 and the reproducible target temperature. In S11, the valve opening period, the valve opening degree, and the valve opening start timing of the EGR control valve 13 are calculated from the corresponding maps using the engine speed and the necessary air amount calculated in S10. In S12, the required reforming fuel amount is calculated from the temperature of the fuel reforming catalyst 16 and the reproducible target temperature. In S13, the fuel injection period and the fuel injection start timing of the reforming fuel injection valve 14 are calculated from the corresponding maps using the engine speed and the required reforming fuel amount calculated in S12. In S14, the second regeneration mode for controlling the EGR control valve 13 and the reforming fuel injection valve 14 under the conditions calculated in S11 and S13 is performed. That is, if the regeneration of the fuel reforming catalyst 16 is insufficient in the first regeneration mode, and if the fuel cut operation is continued, the second regeneration mode for supplying both air and fuel to the fuel reforming catalyst 16 is performed. Implemented immediately.

Ｓ１５では、Ｓ１０で算出された必要空気量及びＳ１２で算出された必要改質用燃料量が燃料改質触媒１６に供給されると第２再生モードが終了した判定する。第２再生モードが終了した場合には、ＥＧＲ制御弁１３を閉弁し、Ｓ１６へ進む。そして、Ｓ１６では、燃料改質触媒１６の温度が上記再生可能目標温度以上になっているか否かを判定する。燃料改質触媒１６の温度が上記再生可能目標温度以上であれば、燃料改質触媒１６上の触媒毒（硫黄被毒）や煤が燃焼により除去されたものと見なして、今回のルーティンを終了する。一方、燃料改質触媒１６の温度が上記再生可能目標温度に達していない場合には、Ｓ９へ進む。つまり、燃料改質触媒１６の再生が、第２再生モードを実施しても不十分な場合、本実施例では上記燃料カット運転が継続する限り、燃料改質触媒１６の再生が完了するまで第２再生モードが繰り返し実施される。   In S15, when the required air amount calculated in S10 and the required reforming fuel amount calculated in S12 are supplied to the fuel reforming catalyst 16, it is determined that the second regeneration mode has ended. When the second regeneration mode is completed, the EGR control valve 13 is closed and the process proceeds to S16. In S16, it is determined whether or not the temperature of the fuel reforming catalyst 16 is equal to or higher than the renewable target temperature. If the temperature of the fuel reforming catalyst 16 is equal to or higher than the reproducible target temperature, it is assumed that the catalyst poison (sulfur poisoning) and soot on the fuel reforming catalyst 16 have been removed by combustion, and the current routine is finished. To do. On the other hand, if the temperature of the fuel reforming catalyst 16 has not reached the reproducible target temperature, the process proceeds to S9. That is, if regeneration of the fuel reforming catalyst 16 is insufficient even if the second regeneration mode is performed, in this embodiment, as long as the fuel cut operation continues, the regeneration of the fuel reforming catalyst 16 is completed until the regeneration of the fuel reforming catalyst 16 is completed. Two playback modes are repeatedly performed.

なお、空気のみを供給する第１再生モードで燃料改質触媒１６が上記再生可能目標温度に達しない場合には、酸化反応するものが燃料改質触媒１６上になく、空気量が多くなっても、燃料改質触媒１６が過度に高温になる可能性は低いと考えられる。そこで、第２再生モードにおいては、ＥＧＲ制御弁１３を必要空気量に応じて制御するのではなく、単に弁開度で制御するようにしてもよい。例えば、第２再生モードでは、ＥＧＲ制御弁１３を予め設定された所定の弁開度に設定したり、上記必要改質用燃料量に応じて設定される弁開度に設定するようにしてもよい。   If the fuel reforming catalyst 16 does not reach the reproducible target temperature in the first regeneration mode in which only air is supplied, there is no oxidation reaction on the fuel reforming catalyst 16 and the amount of air increases. However, it is considered that the possibility that the fuel reforming catalyst 16 becomes too high is low. Therefore, in the second regeneration mode, the EGR control valve 13 may not be controlled according to the required air amount, but simply controlled by the valve opening. For example, in the second regeneration mode, the EGR control valve 13 may be set to a predetermined valve opening that is set in advance, or may be set to a valve opening that is set according to the required amount of reforming fuel. Good.

１…内燃機関
２…吸気通路
３…排気通路
１２…ＥＧＲ通路
１３…ＥＧＲ制御弁
１４…改質用燃料噴射弁
１６…燃料改質触媒
１７…ＥＧＲクーラ
１８…ＥＣＵ
１９…温度センサ
２０…水素センサ
２１…ＥＧＲガス温度センサ DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 2 ... Intake passage 3 ... Exhaust passage 12 ... EGR passage 13 ... EGR control valve 14 ... Reforming fuel injection valve 16 ... Fuel reforming catalyst 17 ... EGR cooler 18 ... ECU
19 ... Temperature sensor 20 ... Hydrogen sensor 21 ... EGR gas temperature sensor

Claims (5)

排気の一部を吸気通路に還流するＥＧＲ通路と、上記ＥＧＲ通路に改質用燃料を噴射する改質用燃料噴射弁と、上記ＥＧＲ通路に介装され、上記改質用燃料から改質ガスを生成する燃料改質触媒と、上記ＥＧＲ通路を流れるＥＧＲ量を制御するＥＧＲ制御弁と、を有する内燃機関の制御装置において、
上記燃料改質触媒の改質ガス生成能力が低下すると、上記燃料改質触媒の第１の再生処理として、上記燃料改質触媒の温度が所定温度以上で、かつ上記内燃機関への燃料供給を停止する燃料カット時に、上記ＥＧＲ制御弁を開弁して上記燃料改質触媒へ所定量の空気を供給し、
上記第１の再生処理を行っても、上記燃料改質触媒の改質ガス生成能力が低下している場合には、上記燃料改質触媒の第２の再生処理として、上記燃料改質触媒の温度が所定温度以上で、かつ上記内燃機関への燃料供給を停止する燃料カット時に、上記ＥＧＲ制御弁を開弁して上記燃料改質触媒へ空気を供給すると共に、上記改質用燃料噴射弁から上記改質用燃料を噴射して上記燃料改質触媒に所定量の上記改質用燃料を供給し、
上記第２の再生処理の開始時における上記燃料改質触媒の温度が低いほど、上記第２の再生処理期間中に上記燃料改質触媒に供給される空気量及び改質用燃料量が多くなるように設定されていることを特徴とする内燃機関の制御装置。 An EGR passage that recirculates part of the exhaust gas to the intake passage, a reforming fuel injection valve that injects reforming fuel into the EGR passage, and a reformed gas from the reforming fuel that is interposed in the EGR passage. A control device for an internal combustion engine, comprising: a fuel reforming catalyst for generating EGR; and an EGR control valve for controlling an EGR amount flowing through the EGR passage.
When the reformed gas generation capacity of the fuel reforming catalyst decreases, as a first regeneration process of the fuel reforming catalyst, the temperature of the fuel reforming catalyst is equal to or higher than a predetermined temperature and fuel is supplied to the internal combustion engine. At the time of fuel cut to stop, the EGR control valve is opened to supply a predetermined amount of air to the fuel reforming catalyst ,
If the reformed gas generation capacity of the fuel reforming catalyst is reduced even after the first regeneration process is performed, the second reforming process of the fuel reforming catalyst is performed as a second regeneration process of the fuel reforming catalyst. At the time of fuel cut when the temperature is equal to or higher than a predetermined temperature and the fuel supply to the internal combustion engine is stopped, the EGR control valve is opened to supply air to the fuel reforming catalyst, and the reforming fuel injection valve From which the reforming fuel is injected to supply a predetermined amount of the reforming fuel to the fuel reforming catalyst,
The lower the temperature of the fuel reforming catalyst at the start of the second regeneration process, the larger the amount of air and reforming fuel supplied to the fuel reforming catalyst during the second regeneration process period. A control device for an internal combustion engine characterized by being set as described above . 上記第１の再生処理の開始時における上記燃料改質触媒の温度が低いほど、上記第１の再生処理期間中に上記燃料改質触媒に供給される空気量が多くなるように設定されていることを特徴とする請求項１に記載の内燃機関の制御装置。   The lower the temperature of the fuel reforming catalyst at the start of the first regeneration process, the greater the amount of air supplied to the fuel reforming catalyst during the first regeneration process period. The control apparatus for an internal combustion engine according to claim 1. 上記第１の再生処理中に上記燃料改質触媒に供給される空気量が多くなるほど、上記ＥＧＲ制御弁の弁開度は大きくなり、上記ＥＧＲ制御弁の開弁期間は長くなるよう設定されることを特徴とする請求項２に記載の内燃機関の制御装置。 As the amount of air supplied to the fuel reforming catalyst in said first regeneration processing increases, the valve opening degree of the EGR control valve become significant, the opening period of the EGR control valve cormorants I become longer the control device according to claim 2, characterized in that it is configured. 上記第２の再生処理中に上記燃料改質触媒に供給される空気量が多くなるほど、上記ＥＧＲ制御弁の弁開度は大きくなり、上記ＥＧＲ制御弁の開弁期間は長くなるよう設定され、
上記第２の再生処理中に上記燃料改質触媒に供給される改質用燃料量が多くなるほど、上記改質用燃料噴射弁の噴射期間が長くなるよう設定されていることを特徴とする請求項１〜３のいずれかに記載の内燃機関の制御装置。 As the amount of air supplied to the fuel reforming catalyst in the second regeneration processing increases, the valve opening degree of the EGR control valve become significant, the opening period of the EGR control valve cormorants I become longer It is set,
The injection period of the reforming fuel injection valve is set to become longer as the amount of reforming fuel supplied to the fuel reforming catalyst during the second regeneration process increases. Item 4. The control device for an internal combustion engine according to any one of Items 1 to 3 . 上記第２の再生処理を行っても、上記燃料改質触媒の改質ガス生成能力が低下している場合には、再度、上記第２の再生処理を実施することを特徴とする請求項４に記載の内燃機関の制御装置。 Said even if the second regeneration process, when the reformed gas generating capability of the fuel reforming catalyst is reduced, claim, characterized in that re-implementing the second reproduction process 4 The control apparatus of the internal combustion engine described in 1.
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