JP2008231926A - Exhaust emission control device of internal combustion engine - Google Patents

Exhaust emission control device of internal combustion engine Download PDF

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JP2008231926A
JP2008231926A JP2007068163A JP2007068163A JP2008231926A JP 2008231926 A JP2008231926 A JP 2008231926A JP 2007068163 A JP2007068163 A JP 2007068163A JP 2007068163 A JP2007068163 A JP 2007068163A JP 2008231926 A JP2008231926 A JP 2008231926A
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fuel ratio
fuel
air
exhaust passage
catalyst
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Yuji Kanto
勇二 関東
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Toyota Motor Corp
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<P>PROBLEM TO BE SOLVED: To provide a technology with which an air fuel ratio of exhaust gas flowing in a storage-reduction type NOx catalyst provided to an exhaust passage can be favorably controlled to a target air fuel ratio. <P>SOLUTION: A fuel addition valve 9 is provided to an exhaust passage 3 at the upstream side from a NOx catalyst 6. An upstream side air fuel ratio sensor 11 is provided to the exhaust passage 3 on the upstream side from the fuel addition valve 9. A downstream side air fuel ratio sensor 12 is provided to the exhaust passage 3 at the downstream side from the NOx catalyst 6. A catalyst 8 having oxidation function is provided to the exhaust passage 3 at the upstream side from the upstream side air fuel ratio sensor 11. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、内燃機関の排気通路に設けられた吸蔵還元型ＮＯｘ触媒を備えた内燃機関の排気浄化装置に関する。   The present invention relates to an exhaust gas purification apparatus for an internal combustion engine including an NOx storage reduction catalyst provided in an exhaust passage of the internal combustion engine.

内燃機関の排気通路に吸蔵還元型ＮＯｘ触媒（以下、単にＮＯｘ触媒と称する）が設けられている場合、該ＮＯｘ触媒に吸蔵されたＮＯｘを還元するＮＯｘ還元制御や該ＮＯｘ触媒に吸蔵されたＳＯｘを還元するＳＯｘ被毒回復制御が行われる。ＮＯｘ還元制御やＳＯｘ被毒回復制御の実行時においては、ＮＯｘ触媒に流入する排気の空燃比を通常運転時（即ち、ＮＯｘ還元制御やＳＯｘ被毒回復制御が実行されていない時）よりも低下させて制御毎に定めたれた目標空燃比に制御する必要がある。   When an NOx storage reduction catalyst (hereinafter simply referred to as NOx catalyst) is provided in the exhaust passage of the internal combustion engine, NOx reduction control for reducing NOx stored in the NOx catalyst and SOx stored in the NOx catalyst are stored. The SOx poisoning recovery control for reducing the amount is performed. When executing NOx reduction control or SOx poisoning recovery control, the air-fuel ratio of the exhaust gas flowing into the NOx catalyst is lower than during normal operation (that is, when NOx reduction control or SOx poisoning recovery control is not executed). Thus, it is necessary to control to the target air-fuel ratio determined for each control.

ＮＯｘ触媒に流入する排気の空燃比を低下させる方法としては、内燃機関の気筒内での混合気の空燃比（以下、筒内空燃比と称する）を低下させると共に、ＮＯｘ触媒よりも上流側の排気通路に設けられた燃料添加弁から排気中に燃料を添加する方法がある。   As a method for reducing the air-fuel ratio of the exhaust gas flowing into the NOx catalyst, the air-fuel ratio of the air-fuel mixture in the cylinder of the internal combustion engine (hereinafter referred to as the in-cylinder air-fuel ratio) is reduced, and at the upstream side of the NOx catalyst. There is a method of adding fuel into the exhaust from a fuel addition valve provided in the exhaust passage.

特許文献１には、ターボチャージャのタービンハウジングよりも下流側の排気通路に、空燃比センサ、燃料添加弁、ＮＯｘ触媒、温度センサ、ＮＯｘ触媒を担持したフィルタ、酸化触媒、温度センサ、空燃比センサを上流から順に設けた構成が開示されている。
特開２００５−１０５８２１号公報 特開２００５−１０５８２８号公報 特開２００３−２８６８７８号公報 特開２００５−０６９０８６号公報 特開２００５−０７６６０３号公報 Patent Document 1 discloses an air-fuel ratio sensor, a fuel addition valve, a NOx catalyst, a temperature sensor, a filter carrying a NOx catalyst, an oxidation catalyst, a temperature sensor, and an air-fuel ratio sensor in an exhaust passage downstream of the turbine housing of the turbocharger. Is disclosed in order from the upstream.
JP 2005-105821 A Japanese Patent Laying-Open No. 2005-105828 JP 2003-286878 A Japanese Patent Laying-Open No. 2005-069086 JP 2005-076603 A

筒内空燃比を低下させることで内燃機関から排出される排気の空燃比を低下させることが出来る。そして、排気通路に設けられた燃料添加弁から排気中に燃料を添加することで排気の空燃比をさらに低下させることが出来る。   By reducing the in-cylinder air-fuel ratio, the air-fuel ratio of the exhaust discharged from the internal combustion engine can be reduced. The fuel / air ratio of the exhaust gas can be further reduced by adding fuel into the exhaust gas from the fuel addition valve provided in the exhaust passage.

しかしながら、燃料添加弁から添加された燃料は気化し難い。そのため、燃料添加弁からの燃料添加量が過剰に多くなると、燃料がＮＯｘ触媒をすり抜けることによる白煙の発生や、ＮＯｘ触媒に付着した燃料が酸化することによるＮＯｘ触媒の過昇温を招く虞がある。また、燃料添加弁からの燃料添加量が過剰に多くなると、燃料が添加された排気の空燃比を空燃比センサの検出値に基づいて高精度で検出することが困難となる虞がある。   However, the fuel added from the fuel addition valve is difficult to vaporize. Therefore, if the amount of fuel added from the fuel addition valve becomes excessive, white smoke may be generated due to the fuel passing through the NOx catalyst, or the NOx catalyst may be excessively heated due to oxidation of the fuel adhering to the NOx catalyst. There is. If the amount of fuel added from the fuel addition valve is excessively large, it may be difficult to detect the air-fuel ratio of the exhaust gas to which fuel has been added with high accuracy based on the detection value of the air-fuel ratio sensor.

一方、筒内空燃比を過剰に低下させると失火等の問題を招く虞がある。   On the other hand, if the in-cylinder air-fuel ratio is excessively reduced, there is a risk of causing problems such as misfire.

本発明は、上記問題に鑑みてなされたものであって、排気通路に設けられたＮＯｘ触媒に流入する排気の空燃比をより好適に目標空燃比に制御する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 provides a technique capable of more suitably controlling the air-fuel ratio of exhaust flowing into the NOx catalyst provided in the exhaust passage to the target air-fuel ratio. With the goal.

本発明においては、ＮＯｘ触媒よりも上流側の排気通路に燃料添加弁が設けられている。また、燃料添加弁よりも上流側の排気通路に上流側空燃比センサが設けられており、ＮＯｘ触媒よりも下流側の排気通路に下流側空燃比センサが設けられている。さらに、上流
側空燃比センサよりも上流側の排気通路に酸化機能を有する触媒（以下、酸化機能触媒と称する）が設けられている。 In the present invention, a fuel addition valve is provided in the exhaust passage upstream of the NOx catalyst. An upstream air-fuel ratio sensor is provided in the exhaust passage upstream of the fuel addition valve, and a downstream air-fuel ratio sensor is provided in the exhaust passage downstream of the NOx catalyst. Further, a catalyst having an oxidation function (hereinafter referred to as an oxidation function catalyst) is provided in the exhaust passage upstream of the upstream air-fuel ratio sensor.

より詳しくは、本発明に係る内燃機関の排気浄化装置は、
内燃機関の排気通路に設けられた吸蔵還元型ＮＯｘ触媒と、
該吸蔵還元型ＮＯｘ触媒よりも上流側の前記排気通路に設けられ排気中に燃料を添加する燃料添加弁と、
該燃料添加弁よりも上流側の前記排気通路に設けられた上流側空燃比センサと、
前記吸蔵還元型ＮＯｘ触媒よりも下流側の前記排気通路に設けられた下流側空燃比センサと、
前記上流側空燃比センサよりも上流側の前記排気通路に設けられた酸化機能を有する触媒と、を備えたことを特徴とする。 More specifically, the exhaust gas purification apparatus for an internal combustion engine according to the present invention is
An NOx storage reduction catalyst provided in the exhaust passage of the internal combustion engine;
A fuel addition valve that is provided in the exhaust passage upstream of the NOx storage reduction catalyst and adds fuel to the exhaust;
An upstream air-fuel ratio sensor provided in the exhaust passage upstream of the fuel addition valve;
A downstream air-fuel ratio sensor provided in the exhaust passage downstream of the NOx storage reduction catalyst;
And a catalyst having an oxidation function provided in the exhaust passage upstream of the upstream air-fuel ratio sensor.

本発明によれば、筒内空燃比を低下させると共に燃料添加弁から燃料を添加することで流入排気の空燃比を低下させることが出来る。そして、上流側空燃比センサの検出値に基づいて筒内空燃比を制御し、下流側空燃比センサの検出値に基づいて燃料添加弁からの燃料添加量を制御することで、流入排気の空燃比を目標空燃比に制御することが出来る。   According to the present invention, the air-fuel ratio of the inflowing exhaust gas can be reduced by reducing the in-cylinder air-fuel ratio and adding fuel from the fuel addition valve. The in-cylinder air-fuel ratio is controlled based on the detection value of the upstream air-fuel ratio sensor, and the fuel addition amount from the fuel addition valve is controlled based on the detection value of the downstream air-fuel ratio sensor, thereby The fuel ratio can be controlled to the target air fuel ratio.

また、本発明では、燃料添加弁よりも上流側の排気通路に酸化機能触媒が設けられている。この酸化機能触媒において排気中の燃料成分（ＣＯやＨＣ等）が酸化され、そのときに排気中の酸素が消費される。そのため、流入排気の空燃比を目標空燃比まで低下させるために燃料添加弁から添加する燃料の量をより少ない量をすることが出来る。その結果、白煙の発生やＮＯｘ触媒の過昇温を抑制することが出来る。   In the present invention, the oxidation function catalyst is provided in the exhaust passage upstream of the fuel addition valve. In this oxidation functional catalyst, fuel components (CO, HC, etc.) in the exhaust are oxidized, and oxygen in the exhaust is consumed at that time. Therefore, the amount of fuel added from the fuel addition valve to reduce the air-fuel ratio of the inflowing exhaust gas to the target air-fuel ratio can be made smaller. As a result, generation of white smoke and excessive temperature rise of the NOx catalyst can be suppressed.

また、筒内空燃比を低下させることによって、内燃機関から粒径が大きく蒸発し難い燃料成分が排出される場合がある。本発明では、このような燃料成分が酸化機能触媒によって酸化される。そのため、上流側空燃比センサに燃料成分が付着することを抑制することが出来る。これにより、上流側空燃比センサによる排気の空燃比の検出精度を向上させることが出来るため、筒内空燃比をより高精度で制御することが可能となる。その結果、内燃機関での失火の発生等を抑制することが出来る。   Further, by reducing the in-cylinder air-fuel ratio, a fuel component that has a large particle size and is difficult to evaporate may be discharged from the internal combustion engine. In the present invention, such a fuel component is oxidized by the oxidation functional catalyst. Therefore, it is possible to suppress the fuel component from adhering to the upstream air-fuel ratio sensor. Thereby, the detection accuracy of the air-fuel ratio of the exhaust gas by the upstream air-fuel ratio sensor can be improved, so that the in-cylinder air-fuel ratio can be controlled with higher accuracy. As a result, the occurrence of misfire in the internal combustion engine can be suppressed.

さらに、燃料添加弁から添加する燃料の量をより少ない量とすることが出来ると共に筒内空燃比をより高精度で制御することが可能となることで、流入排気の空燃比をより高精度で目標空燃比に制御することが出来る。   Furthermore, the amount of fuel added from the fuel addition valve can be made smaller and the in-cylinder air-fuel ratio can be controlled with higher accuracy, so that the air-fuel ratio of the inflowing exhaust gas can be controlled with higher accuracy. The target air-fuel ratio can be controlled.

本発明は、排気通路に設けられたＮＯｘ触媒に流入する排気の空燃比をより好適に目標空燃比に制御することが出来る。   The present invention can more suitably control the air-fuel ratio of the exhaust gas flowing into the NOx catalyst provided in the exhaust passage to the target air-fuel ratio.

以下、本発明に係る内燃機関の排気浄化装置の具体的な実施形態について図面に基づいて説明する。   Hereinafter, specific embodiments of an exhaust emission control device for an internal combustion engine according to the present invention will be described with reference to the drawings.

＜内燃機関の吸排気系の概略構成＞
図１は、本実施例に係る内燃機関の吸排気系の概略構成を示す図である。内燃機関１は車両駆動用のディーゼルエンジンである。内燃機関１には吸気通路２および排気通路３が接続されている。吸気通路２にはターボチャージャ５のコンプレッサハウジング５ａが設置されている。吸気通路２におけるコンプレッサハウジング５ａよりも下流側にはスロットル弁４が設けられている。 <Schematic configuration of intake and exhaust system of internal combustion engine>
FIG. 1 is a diagram showing a schematic configuration of an intake / exhaust system of an internal combustion engine according to the present embodiment. The internal combustion engine 1 is a diesel engine for driving a vehicle. An intake passage 2 and an exhaust passage 3 are connected to the internal combustion engine 1. A compressor housing 5 a of a turbocharger 5 is installed in the intake passage 2. A throttle valve 4 is provided in the intake passage 2 on the downstream side of the compressor housing 5a.

排気通路３にはターボチャージャ５のタービンハウジング５ｂが設置されている。排気通路３におけるタービンハウジング５ｂより下流側にはＮＯｘ触媒６が設けられている。排気通路３において、ＮＯｘ触媒６の直上流には第一酸化触媒７が設けられており、さらに酸化触媒７よりも上流側には燃料添加弁９が設けられている。燃料添加弁９は排気通路３を流れる排気中に燃料を添加する。   A turbine housing 5 b of the turbocharger 5 is installed in the exhaust passage 3. A NOx catalyst 6 is provided downstream of the turbine housing 5b in the exhaust passage 3. In the exhaust passage 3, a first oxidation catalyst 7 is provided immediately upstream of the NOx catalyst 6, and a fuel addition valve 9 is provided upstream of the oxidation catalyst 7. The fuel addition valve 9 adds fuel to the exhaust gas flowing through the exhaust passage 3.

排気通路３におけるタービンハウジング５ｂよりも下流側且つ燃料添加弁９よりも上流側には第二酸化触媒８が設けられている。さらに、排気通路３には、排気通路３を流れる排気の空燃比を検出する上流側空燃比センサ１１および下流側空燃比センサ１２が設けられている。上流側空燃比センサ１１は第二酸化触媒８よりも下流側且つ燃料添加弁９よりも上流側に設けられており、下流側空燃比センサ１２はＮＯｘ触媒６よりも下流側に設けられている。   A second dioxide catalyst 8 is provided in the exhaust passage 3 downstream of the turbine housing 5 b and upstream of the fuel addition valve 9. Further, the exhaust passage 3 is provided with an upstream air-fuel ratio sensor 11 and a downstream air-fuel ratio sensor 12 that detect the air-fuel ratio of the exhaust gas flowing through the exhaust passage 3. The upstream air-fuel ratio sensor 11 is provided downstream of the second dioxide catalyst 8 and upstream of the fuel addition valve 9, and the downstream air-fuel ratio sensor 12 is provided downstream of the NOx catalyst 6.

尚、本実施例においては、第二酸化触媒８が本発明に係る酸化機能触媒に相当する。該第二酸化触媒８は酸化触媒に限られるものではなく、酸化機能を有する触媒であればよい。また、ＮＯｘ触媒６はパティキュレートフィルタに担持された状態であってもよい。   In this embodiment, the second dioxide catalyst 8 corresponds to the oxidation functional catalyst according to the present invention. The second dioxide catalyst 8 is not limited to an oxidation catalyst, and may be any catalyst having an oxidation function. Further, the NOx catalyst 6 may be in a state of being supported by a particulate filter.

また、内燃機関１には、電子制御ユニット（ＥＣＵ）１０が併設されている。このＥＣＵ１０は、内燃機関１の運転条件や運転者の要求に応じて内燃機関１の運転状態を制御するユニットである。ＥＣＵ１０には上流側空燃比センサ１１および下流側空燃比センサ１２が電気的に接続されている。これらの出力信号がＥＣＵ１０に入力される。   The internal combustion engine 1 is also provided with an electronic control unit (ECU) 10. The ECU 10 is a unit that controls the operation state of the internal combustion engine 1 in accordance with the operation conditions of the internal combustion engine 1 and the request of the driver. An upstream air-fuel ratio sensor 11 and a downstream air-fuel ratio sensor 12 are electrically connected to the ECU 10. These output signals are input to the ECU 10.

また、ＥＣＵ１０には、内燃機関１の気筒内に燃料を噴射する燃料噴射弁およびスロットル弁４、燃料添加弁９が電気的に接続されている。ＥＣＵ１０によってこれらが制御される。   The ECU 10 is electrically connected to a fuel injection valve for injecting fuel into the cylinder of the internal combustion engine 1, a throttle valve 4, and a fuel addition valve 9. These are controlled by the ECU 10.

＜ＳＯｘ被毒回復制御＞
本実施例においては、ＮＯｘ触媒６に吸蔵されたＳＯｘを還元すべくＳＯｘ被毒回復制御が行われる。ＮＯｘ触媒６に吸蔵されたＳＯｘを還元するためには、ＮＯｘ触媒６の温度を上昇させると共にＮＯｘ触媒６に流入する排気（流入排気）の空燃比を通常運転時よりも低下させて目標空燃比に制御することが必要である。ここで、目標空燃比は、ＳＯｘの還元が可能となる空燃比であって実験等によって予め定められている。 <SOx poisoning recovery control>
In this embodiment, SOx poisoning recovery control is performed to reduce the SOx stored in the NOx catalyst 6. In order to reduce the SOx stored in the NOx catalyst 6, the temperature of the NOx catalyst 6 is raised and the air-fuel ratio of the exhaust gas (inflowing exhaust gas) flowing into the NOx catalyst 6 is lowered than in the normal operation to reduce the target air-fuel ratio. It is necessary to control. Here, the target air-fuel ratio is an air-fuel ratio at which SOx can be reduced, and is determined in advance by experiments or the like.

本実施例に係るＳＯｘ被毒回復制御は、内燃機関１の筒内空燃比を低下させると共に燃料添加弁９から燃料を添加することで実現される。内燃機関１の筒内空燃比を低下させる方法としては、スロットル弁４の開度を小さくすることで入空気量を減少させる方法や内燃機関１における燃料噴射量を増加させる方法等を例示することが出来る。   The SOx poisoning recovery control according to this embodiment is realized by reducing the in-cylinder air-fuel ratio of the internal combustion engine 1 and adding fuel from the fuel addition valve 9. Examples of methods for reducing the in-cylinder air-fuel ratio of the internal combustion engine 1 include a method of reducing the amount of intake air by reducing the opening of the throttle valve 4 and a method of increasing the fuel injection amount in the internal combustion engine 1. I can do it.

そして、ＳＯｘ被毒回復制御の実行時においては、上流側空燃比センサ１１の検出値に基づいて内燃機関１の筒内空燃比を制御し、下流側空燃比センサ１２の検出値に基づいて燃料添加弁９からの燃料添加量を制御することで、流入排気の空燃比を目標空燃比に制御する。   When executing the SOx poisoning recovery control, the cylinder air-fuel ratio of the internal combustion engine 1 is controlled based on the detected value of the upstream air-fuel ratio sensor 11, and the fuel is determined based on the detected value of the downstream air-fuel ratio sensor 12. By controlling the amount of fuel added from the addition valve 9, the air-fuel ratio of the inflowing exhaust gas is controlled to the target air-fuel ratio.

本実施例においては、燃料添加弁９よりも上流側の排気通路３に第二酸化触媒８が設けられている。この第二酸化触媒８において排気中の燃料成分が酸化されることで排気中の酸素が消費される。そのため、第二酸化触媒８より下流側に流れる排気中の酸素量が減少する。従って、流入排気の空燃比を目標空燃比まで低下させるために燃料添加弁９から添加する燃料量をより少ない量とすることが出来る。   In the present embodiment, the second dioxide catalyst 8 is provided in the exhaust passage 3 upstream of the fuel addition valve 9. Oxygen in the exhaust is consumed by oxidizing the fuel component in the exhaust in the second dioxide catalyst 8. Therefore, the amount of oxygen in the exhaust gas flowing downstream from the second dioxide catalyst 8 is reduced. Therefore, the amount of fuel added from the fuel addition valve 9 to reduce the air-fuel ratio of the inflowing exhaust gas to the target air-fuel ratio can be made smaller.

燃料添加弁９からの燃料添加量をより少ない量とすることによって、ＮＯｘ触媒６をす
り抜ける燃料の量やＮＯｘ触媒６に付着する燃料の量を減少させることが出来る。その結果、白煙の発生やＮＯｘ触媒６の過昇温を抑制することが出来る。 By making the amount of fuel added from the fuel addition valve 9 smaller, the amount of fuel passing through the NOx catalyst 6 and the amount of fuel adhering to the NOx catalyst 6 can be reduced. As a result, generation of white smoke and excessive temperature rise of the NOx catalyst 6 can be suppressed.

また、筒内空燃比を低下させることで、内燃機関１から粒径が大きく蒸発し難い燃料成分が排出された場合であっても、該燃料成分が第二酸化触媒８によって酸化される。そのため、上流側空燃比センサ１１に燃料成分が付着することを抑制することが出来る。これにより、上流側空燃比センサ１１による排気の空燃比の検出精度を向上させることが出来るため、筒内空燃比をより高精度で制御することが可能となる。その結果、内燃機関１での失火の発生等を抑制することが出来る。   Further, by reducing the in-cylinder air-fuel ratio, the fuel component is oxidized by the second dioxide catalyst 8 even when the fuel component having a large particle size and not easily evaporated is discharged from the internal combustion engine 1. Therefore, it is possible to suppress the fuel component from adhering to the upstream air-fuel ratio sensor 11. Thereby, the detection accuracy of the air-fuel ratio of the exhaust by the upstream air-fuel ratio sensor 11 can be improved, so that the in-cylinder air-fuel ratio can be controlled with higher accuracy. As a result, the occurrence of misfire in the internal combustion engine 1 can be suppressed.

さらに、燃料添加弁９から添加する燃料の量を減らすことが出来ると共に筒内空燃比をより高精度で制御することが可能となることで、流入排気の空燃比をより高精度で目標空燃比に制御することが出来る。   Further, the amount of fuel added from the fuel addition valve 9 can be reduced and the in-cylinder air-fuel ratio can be controlled with higher accuracy, so that the air-fuel ratio of the inflowing exhaust gas can be controlled with higher accuracy. Can be controlled.

従って、本実施例によれば、ＳＯｘ被毒回復制御の実行時において、流入排気の空燃比をより好適に目標空燃比に制御することが出来る。   Therefore, according to the present embodiment, it is possible to more suitably control the air-fuel ratio of the inflowing exhaust gas to the target air-fuel ratio when executing the SOx poisoning recovery control.

また、本実施例の構成によれば、上流側空燃比センサ１１の検出値と下流側空燃比センサ１２の検出値とに基づいて燃料添加弁９の詰まり等の異常を検出することが出来る。   Further, according to the configuration of the present embodiment, an abnormality such as clogging of the fuel addition valve 9 can be detected based on the detected value of the upstream air-fuel ratio sensor 11 and the detected value of the downstream air-fuel ratio sensor 12.

尚、本実施例においては、ＮＯｘ触媒６に吸蔵されたＮＯｘを還元するＮＯｘ還元制御の実行時においても、上記説明したＳＯｘ被毒回復制御の実行時と同様の方法で流入排気の空燃比を目標空燃比に制御してもよい。   In the present embodiment, the air-fuel ratio of the inflowing exhaust gas is set in the same manner as in the execution of the SOx poisoning recovery control described above even when the NOx reduction control for reducing the NOx stored in the NOx catalyst 6 is executed. You may control to a target air fuel ratio.

また、本実施例では、ＳＯｘ被毒回復制御の実行時に、燃料添加弁９による燃料添加に加えて内燃機関１における副燃料噴射を実行してもよい。この場合、副燃料噴射は、主燃料噴射よりも後の時期であって噴射された燃料が未燃の状態で内燃機関１から排出されるタイミングで実行される。本実施例において、このような副燃料噴射が実行されると、内燃機関１から排出された未燃燃料成分が第二酸化触媒８において酸化される。このときに生じる酸化熱によって排気を昇温させることが出来る。   Further, in this embodiment, when performing the SOx poisoning recovery control, the sub fuel injection in the internal combustion engine 1 may be executed in addition to the fuel addition by the fuel addition valve 9. In this case, the auxiliary fuel injection is executed at a timing after the main fuel injection and when the injected fuel is discharged from the internal combustion engine 1 in an unburned state. In this embodiment, when such sub fuel injection is executed, unburned fuel components discharged from the internal combustion engine 1 are oxidized in the second dioxide catalyst 8. The temperature of the exhaust can be raised by oxidation heat generated at this time.

本実施例に係る内燃機関の吸排気系の概略構成を示す図。The figure which shows schematic structure of the intake / exhaust system of the internal combustion engine which concerns on a present Example.

符号の説明Explanation of symbols

１・・・内燃機関
２・・・吸気通路
３・・・排気通路
４・・・スロットル弁
６・・・吸蔵還元型ＮＯｘ触媒
７・・・第一酸化触媒
８・・・第二酸化触媒
９・・・燃料添加弁
１０・・ＥＣＵ
１１・・上流側空燃比センサ
１２・・下流側空燃比センサ DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 2 ... Intake passage 3 ... Exhaust passage 4 ... Throttle valve 6 ... NOx storage reduction catalyst 7 ... First oxidation catalyst 8 ... Second dioxide catalyst 9・ ・ Fuel addition valve 10 ・ ・ ECU
11. ・ Upstream air-fuel ratio sensor 12. ・ Downstream air-fuel ratio sensor

Claims (1)

内燃機関の排気通路に設けられた吸蔵還元型ＮＯｘ触媒と、
該吸蔵還元型ＮＯｘ触媒よりも上流側の前記排気通路に設けられ排気中に燃料を添加する燃料添加弁と、
該燃料添加弁よりも上流側の前記排気通路に設けられた上流側空燃比センサと、
前記吸蔵還元型ＮＯｘ触媒よりも下流側の前記排気通路に設けられた下流側空燃比センサと、
前記上流側空燃比センサよりも上流側の前記排気通路に設けられた酸化機能を有する触媒と、を備えたことを特徴とする内燃機関の排気浄化装置。 An NOx storage reduction catalyst provided in the exhaust passage of the internal combustion engine;
A fuel addition valve that is provided in the exhaust passage upstream of the NOx storage reduction catalyst and adds fuel to the exhaust;
An upstream air-fuel ratio sensor provided in the exhaust passage upstream of the fuel addition valve;
A downstream air-fuel ratio sensor provided in the exhaust passage downstream of the NOx storage reduction catalyst;
An exhaust gas purification apparatus for an internal combustion engine, comprising: a catalyst having an oxidation function provided in the exhaust passage upstream of the upstream air-fuel ratio sensor.
JP2007068163A 2007-03-16 2007-03-16 Exhaust emission control device of internal combustion engine Withdrawn JP2008231926A (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011030419A1 (en) 2009-09-10 2011-03-17 トヨタ自動車株式会社 Exhaust gas purification device for internal combustion engine
US20130017121A1 (en) * 2011-07-14 2013-01-17 Toyota Jidosha Kabushiki Kaisha Exhaust purification system of internal combustion engine
US8707682B2 (en) 2011-08-25 2014-04-29 Toyota Jidosha Kabushiki Kaisha Exhaust purification system of internal combustion engine
US9028763B2 (en) 2011-11-30 2015-05-12 Toyota Jidosha Kabushiki Kaisha Exhaust purification system of internal combustion engine
US9623375B2 (en) 2010-03-15 2017-04-18 Toyota Jidosha Kabushiki Kaisha Exhaust purification system of internal combustion engine

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011030419A1 (en) 2009-09-10 2011-03-17 トヨタ自動車株式会社 Exhaust gas purification device for internal combustion engine
US8584451B2 (en) 2009-09-10 2013-11-19 Toyota Jidosha Kabushiki Kaisha Exhaust gas purification apparatus for an internal combustion engine
US9623375B2 (en) 2010-03-15 2017-04-18 Toyota Jidosha Kabushiki Kaisha Exhaust purification system of internal combustion engine
US20130017121A1 (en) * 2011-07-14 2013-01-17 Toyota Jidosha Kabushiki Kaisha Exhaust purification system of internal combustion engine
US8820054B2 (en) * 2011-07-14 2014-09-02 Toyota Jidosha Kabushiki Kaisha Exhaust purification system of internal combustion engine
US8707682B2 (en) 2011-08-25 2014-04-29 Toyota Jidosha Kabushiki Kaisha Exhaust purification system of internal combustion engine
US9028763B2 (en) 2011-11-30 2015-05-12 Toyota Jidosha Kabushiki Kaisha Exhaust purification system of internal combustion engine

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