JP5573817B2 - Exhaust gas purification device for internal combustion engine - Google Patents

Exhaust gas purification device for internal combustion engine Download PDF

Info

Publication number
JP5573817B2
JP5573817B2 JP2011243698A JP2011243698A JP5573817B2 JP 5573817 B2 JP5573817 B2 JP 5573817B2 JP 2011243698 A JP2011243698 A JP 2011243698A JP 2011243698 A JP2011243698 A JP 2011243698A JP 5573817 B2 JP5573817 B2 JP 5573817B2
Authority
JP
Japan
Prior art keywords
value
differential pressure
exhaust
pressure value
filter
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
JP2011243698A
Other languages
Japanese (ja)
Other versions
JP2013100729A (en
Inventor
裕彦 太田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toyota Motor Corp
Original Assignee
Toyota Motor Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Toyota Motor Corp filed Critical Toyota Motor Corp
Priority to JP2011243698A priority Critical patent/JP5573817B2/en
Priority to DE102012219767.2A priority patent/DE102012219767B4/en
Publication of JP2013100729A publication Critical patent/JP2013100729A/en
Application granted granted Critical
Publication of JP5573817B2 publication Critical patent/JP5573817B2/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2066—Selective catalytic reduction [SCR]
    • F01N3/208—Control of selective catalytic reduction [SCR], e.g. dosing of reducing agent
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N11/00—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
    • F01N3/033—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices
    • F01N3/035—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices with catalytic reactors, e.g. catalysed diesel particulate filters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2240/00—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being
    • F01N2240/20—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being a flow director or deflector
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
    • F01N2560/08—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being a pressure sensor
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Exhaust Gas After Treatment (AREA)
  • Processes For Solid Components From Exhaust (AREA)

Description

本発明は、内燃機関の排気浄化装置に関するものである。   The present invention relates to an exhaust emission control device for an internal combustion engine.

例えば特許文献１に記載されているように、排気中の窒素酸化物（ＮＯｘ）を浄化するＮＯｘ浄化触媒の一つである選択還元型ＮＯｘ触媒と、この選択還元型ＮＯｘ触媒でのＮＯｘ浄化に利用する還元剤を排気通路内に供給する還元剤供給機構と、排気通路内に設けられて還元剤を分散させる分散板とを備える内燃機関の排気浄化装置が知られている。   For example, as described in Patent Document 1, a selective reduction type NOx catalyst that is one of NOx purification catalysts that purifies nitrogen oxides (NOx) in exhaust gas, and NOx purification using this selective reduction type NOx catalyst. 2. Description of the Related Art An exhaust gas purification apparatus for an internal combustion engine is known that includes a reducing agent supply mechanism that supplies a reducing agent to be used into an exhaust passage and a dispersion plate that is provided in the exhaust passage and disperses the reducing agent.

この排気浄化装置では、還元剤供給機構から排気通路に向けて尿素水が噴射される。噴射された尿素水は、分散板によって霧化が促進され、排気熱による加水分解によってアンモニアとなる。そしてこのアンモニアが還元剤として選択還元型ＮＯｘ触媒に供給される。   In this exhaust purification device, urea water is injected from the reducing agent supply mechanism toward the exhaust passage. The injected urea water is atomized by the dispersion plate and becomes ammonia by hydrolysis by exhaust heat. This ammonia is supplied as a reducing agent to the selective reduction type NOx catalyst.

特開２００１−５１６６３５号公報JP 2001-516635 A

ところで、分散板に変形などの異常が生じると、尿素水の霧化状態が変化するようになる。そのため、選択還元型ＮＯｘ触媒に供給されるアンモニアの量が変化し、その結果、浄化されるＮＯｘの量、つまりＮＯｘ浄化率が低下するようになる。   By the way, when abnormality such as deformation occurs in the dispersion plate, the state of atomization of urea water changes. Therefore, the amount of ammonia supplied to the selective reduction type NOx catalyst changes, and as a result, the amount of NOx to be purified, that is, the NOx purification rate is lowered.

ここで、ＮＯｘ浄化率の低下は、分散板の異常のみならず、ＮＯｘ浄化触媒の劣化や、還元剤供給機構の異常（例えば還元剤を噴射する噴射弁の異常など）によっても生じる。そのため、ＮＯｘ浄化率が低下したときには、分散板に異常があるにもかかわらず、ＮＯｘ浄化触媒や還元剤供給機構などの誤った部品を交換してしまうおそれがあり、ＮＯｘ浄化率の低下原因を特定することが望ましい。   Here, the reduction of the NOx purification rate is caused not only by the abnormality of the dispersion plate but also by the deterioration of the NOx purification catalyst and the abnormality of the reducing agent supply mechanism (for example, the abnormality of the injection valve for injecting the reducing agent). For this reason, when the NOx purification rate decreases, there is a possibility that erroneous parts such as the NOx purification catalyst and the reducing agent supply mechanism may be replaced despite the abnormality in the dispersion plate. It is desirable to specify.

この発明は、こうした実情に鑑みてなされたものであり、その目的は、ＮＯｘ浄化率が低下する原因の一つである分散板の異常を特定することのできる内燃機関の排気浄化装置を提供することにある。   The present invention has been made in view of such circumstances, and an object of the present invention is to provide an exhaust purification device for an internal combustion engine that can identify an abnormality of a dispersion plate, which is one of the causes of a decrease in the NOx purification rate. There is.

以下、上記目的を達成するための手段及びその作用効果について記載する。なお、本明細書及び特許請求の範囲に記載の「上流」及び「下流」は、排気系での排気の流れ方向を基準にするものである。   In the following, means for achieving the above object and its effects are described. Note that “upstream” and “downstream” described in the present specification and claims are based on the flow direction of the exhaust gas in the exhaust system.

請求項１〜３に記載の発明は、還元剤の供給によりＮＯｘを浄化するＮＯｘ浄化触媒と、還元剤を排気通路内に供給する還元剤供給機構と、排気通路内に設けられて前記ＮＯｘ浄化触媒よりも上流で還元剤を分散させる分散板とを備える内燃機関の排気浄化装置において、前記分散板よりも上流の排気圧を検出する圧力センサを備え、前記ＮＯｘ浄化触媒でのＮＯｘ浄化率が所定値よりも低く、かつ前記排気圧が予め定められた上限圧力値と下限圧力値との間の値でないときには、前記分散板に異常ありと判定する異常判定を行うことをその要旨とする。 The invention described in claims 1 to 3 is provided with a NOx purification catalyst for purifying NOx by supplying a reducing agent, a reducing agent supply mechanism for supplying the reducing agent into the exhaust passage, and the NOx purification provided in the exhaust passage. An exhaust gas purification apparatus for an internal combustion engine comprising a dispersion plate that disperses a reducing agent upstream of a catalyst, and a pressure sensor that detects an exhaust pressure upstream of the dispersion plate, wherein the NOx purification rate of the NOx purification catalyst is If the exhaust pressure is lower than a predetermined value and is not a value between a predetermined upper limit pressure value and a lower limit pressure value, the gist is to perform an abnormality determination that determines that the dispersion plate is abnormal.

分散板に異常が生じると、当該分散板の圧力損失が変化する。そのため、分散板よりも上流の排気圧は、正常時とは異なった異常な値となる。ここで、同排気圧の異常値は、排気系を構成する他の部材での圧力損失が変化した場合にも生じる。しかし、分散板の異常とＮＯｘ浄化率の低下とは高い関連性があるため、ＮＯｘ浄化率の低下と上記排気圧の異常値とがともに生じているときには、分散板に異常が生じている可能性が非常に高い。   When an abnormality occurs in the dispersion plate, the pressure loss of the dispersion plate changes. For this reason, the exhaust pressure upstream of the dispersion plate has an abnormal value different from the normal value. Here, the abnormal value of the exhaust pressure also occurs when pressure loss in other members constituting the exhaust system changes. However, since there is a high correlation between an abnormality in the dispersion plate and a decrease in the NOx purification rate, an abnormality may have occurred in the dispersion plate when both a decrease in the NOx purification rate and the abnormal value of the exhaust pressure occur. The nature is very high.

そこで、同構成では、ＮＯｘ浄化率が所定値よりも低く、かつ上記排気圧が予め定められた上限圧力値と下限圧力値との間の値ではない異常値のときには、分散板に異常ありと判定するようにしている。従って、分散板の異常を特定することができるようになる。 Therefore, in the same configuration, when the NOx purification rate is lower than a predetermined value and the exhaust pressure is an abnormal value that is not a value between a predetermined upper limit pressure value and a lower limit pressure value, the dispersion plate is abnormal. Judgment is made. Therefore, it is possible to specify the abnormality of the dispersion plate.

なお、上記上限圧力値としては、分散板の変形や分散板への異物付着等による圧力損失の増大に伴って排気圧が高くなったときの圧力値を設定することができる。また、上記下限圧力値としては、分散板の変形や分散板の破損等による圧力損失の低下に伴って排気圧が低くなったときの圧力値を設定することができる。   As the upper limit pressure value, it is possible to set a pressure value when the exhaust pressure increases with an increase in pressure loss due to deformation of the dispersion plate, adhesion of foreign matter to the dispersion plate, or the like. In addition, as the lower limit pressure value, a pressure value when the exhaust pressure becomes lower with a decrease in pressure loss due to deformation of the dispersion plate, breakage of the dispersion plate, or the like can be set.

また、請求項１〜３に記載の発明は、前記圧力センサの上流には、排気中の微粒子を捕集するとともに再生処理が行われるフィルタが設けられており、前記再生処理が終了した直後の前記排気圧に基づいて前記異常判定を行うことをその要旨とする。 The invention according to claim 1 to 3, on the upstream of the pre-Symbol pressure sensor, regeneration process with trapping particulate in the exhaust gas filter is provided to be carried out, immediately after the regeneration process has been completed The gist is to perform the abnormality determination based on the exhaust pressure.

排気中の微粒子を捕集するフィルタが上記圧力センサの上流に設けられている場合、フィルタでの微粒子堆積量が圧力センサで検出される排気圧に影響を与える。従って、排気圧に基づく分散板の異常判定を行うに際して、微粒子堆積量の影響による排気圧の変化を、分散板の異常による排気圧の変化であると誤って判定するおそれがある。この点、同構成では、フィルタの再生処理が終了した直後、つまり微粒子堆積量が非常に少なくなっているときの排気圧に基づいて分散板の異常判定を行うようにしている。そのため、分散板の異常判定を行うに際して、微粒子堆積量の影響を極力抑えることができ、これにより分散板の異常判定の精度を高めることができる。   When a filter that collects particulates in the exhaust is provided upstream of the pressure sensor, the amount of particulates accumulated in the filter affects the exhaust pressure detected by the pressure sensor. Therefore, when the abnormality determination of the dispersion plate based on the exhaust pressure is performed, there is a possibility that the change in the exhaust pressure due to the influence of the amount of accumulated particulates is erroneously determined as the change in the exhaust pressure due to the abnormality of the dispersion plate. In this regard, in the same configuration, abnormality determination of the dispersion plate is performed immediately after the filter regeneration process is completed, that is, based on the exhaust pressure when the amount of particulate accumulation is very small. Therefore, when determining the abnormality of the dispersion plate, it is possible to suppress the influence of the accumulation amount of the fine particles as much as possible, thereby improving the accuracy of the abnormality determination of the dispersion plate.

また、請求項１〜３に記載の発明は、前記フィルタの上流及び下流の排気圧の圧力差を検出する差圧センサを有しており、前記再生処理が終了した直後の前記圧力差が予め定められた上限差圧値と下限差圧値との間の値でないときには、前記異常判定を禁止することをその要旨とする。 The invention as claimed in claims 1 to 3 has a differential pressure sensor for detecting a pressure difference between the upstream and downstream exhaust pressure prior Symbol filter, the pressure difference immediately after the regeneration process has been completed The gist is to prohibit the abnormality determination when the value is not between a predetermined upper limit differential pressure value and a lower limit differential pressure value.

上記フィルタでの微粒子堆積量が過剰に多いときや、内燃機関からの微粒子排出量が過剰に多いとき、あるいは上記再生処理が十分に行われていないときには、フィルタの圧力損失が過剰に高くなるため、上記圧力差が大きくなる。一方、溶損等の発生によりフィルタの圧力損失が過剰に低くなると、上記圧力差は小さくなる。   When the amount of particulates accumulated in the filter is excessively large, when the amount of particulates discharged from the internal combustion engine is excessively large, or when the regeneration process is not sufficiently performed, the pressure loss of the filter becomes excessively high. The pressure difference becomes large. On the other hand, if the pressure loss of the filter becomes excessively low due to the occurrence of melting damage, the pressure difference becomes small.

こうしたフィルタの圧力損失の変化は、同フィルタの下流にある上記圧力センサの検出値に影響を与える。そのため、フィルタの圧力損失の異常による排気圧の過度な上昇、あるいは過度な低下を分散板の異常と誤判定してしまうおそれがある。この点、同構成では、再生処理が終了した直後の上記圧力差が予め定められた上限差圧値と下限差圧値との間の値ではない、つまりフィルタの圧力損失が過剰に変化しており異常があるときには、排気圧に基づく分散板の異常判定を禁止するようにしている。そのため、分散板の異常判定を行うに際して、フィルタの圧力損失の異常による悪影響を極力抑えることができ、これにより分散板の異常判定の精度を高めることができる。   Such a change in the pressure loss of the filter affects the detection value of the pressure sensor downstream of the filter. Therefore, there is a risk that an excessive increase or an excessive decrease in the exhaust pressure due to an abnormality in the filter pressure loss may be erroneously determined as an abnormality in the dispersion plate. In this regard, in the same configuration, the pressure difference immediately after the regeneration process is finished is not a value between a predetermined upper limit differential pressure value and a lower limit differential pressure value, that is, the pressure loss of the filter changes excessively. When there is a cage abnormality, the dispersion plate abnormality determination based on the exhaust pressure is prohibited. Therefore, when the abnormality determination of the dispersion plate is performed, an adverse effect due to the abnormality of the pressure loss of the filter can be suppressed as much as possible, thereby improving the accuracy of the determination of the abnormality of the dispersion plate.

また、請求項１〜３に記載の発明は、前記上限差圧値及び前記下限差圧値は、前記フィルタのアッシュ堆積量に応じて可変設定されることをその要旨とする。 The invention according to claim 1 to 3, before Symbol limit pressure value and the lower limit pressure value is its gist to be variably set in accordance with the ash deposition amount of the filter.

フィルタには、潤滑油に由来する成分であって上述した再生処理による燃焼が困難なアッシュが堆積していく。なお、このアッシュとしては、例えば潤滑油の添加剤等に含まれる成分（Ｚｎ、Ｃａ、Ｍｇ、Ｎａ等の金属成分など）が挙げられる。そして、再生処理が終了した直後の上記圧力差は、アッシュの堆積量によっても変化する。そこで、同構成では、上記圧力差が所定の範囲外の値であるかどうかを判定するための上記上限差圧値と上記下限差圧値とを、フィルタのアッシュ堆積量に応じて可変設定するようにしている。従って、分散板の異常判定を行うか否かの判定精度を高めることができるようになる。   Ash that is a component derived from the lubricating oil and difficult to burn by the above-described regeneration process accumulates on the filter. In addition, as this ash, the component (metal components, such as Zn, Ca, Mg, Na, etc.) contained in the additive etc. of lubricating oil, etc. are mentioned, for example. And the said pressure difference immediately after completion | finish of a reproduction | regeneration process changes also with the accumulation amount of ash. Therefore, in this configuration, the upper limit differential pressure value and the lower limit differential pressure value for determining whether or not the pressure difference is a value outside a predetermined range are variably set according to the ash accumulation amount of the filter. I am doing so. Accordingly, it is possible to increase the accuracy of determining whether or not to perform abnormality determination of the dispersion plate.

なお、アッシュ堆積量が多くなるほど上記圧力差は大きくなるため、同構成においては、アッシュ堆積量が多くなるほど上限差圧値及び下限差圧値を大きくすることが望ましい。   Since the pressure difference increases as the ash deposition amount increases, in this configuration, it is desirable to increase the upper limit pressure difference value and the lower limit differential pressure value as the ash deposition amount increases.

アッシュ堆積量は、車両の総走行距離が長くなるほど多くなる。そこで、フィルタのアッシュ堆積量に応じて上記上限差圧値及び下限差圧値を可変設定するに際しては、請求項１に記載の発明によるように、前記内燃機関が搭載された車両の総走行距離が長いほど、前記上限差圧値及び前記下限差圧値は大きくなるように可変設定される、といった構成を採用することができる。 The amount of ash accumulation increases as the total travel distance of the vehicle increases. Therefore, when the upper limit differential pressure value and the lower limit differential pressure value are variably set according to the ash accumulation amount of the filter, the total travel distance of the vehicle on which the internal combustion engine is mounted is set as in the invention according to claim 1. It is possible to adopt a configuration in which the upper limit differential pressure value and the lower limit differential pressure value are variably set so as to increase as the length increases.

また、アッシュは、再生処理での微粒子の燃え残りでもあるため、再生処理の実行回数が多いほどアッシュ堆積量は多くなる。そこで、フィルタのアッシュ堆積量に応じて上記上限差圧値及び下限差圧値を可変設定するに際しては、請求項２に記載の発明によるように、前記再生処理の実行回数が多いほど、前記上限差圧値及び前記下限差圧値は大きくなるように可変設定される、といった構成を採用することもできる。 In addition, since ash is the remaining unburned fine particles in the regeneration process, the amount of ash deposition increases as the number of regeneration processes is increased. Therefore, when variably sets the upper limit pressure value and the lower limit pressure value depending on the ash accumulation amount of the filter, such as by the invention of claim 2, as the number of times the execution of the regeneration process, the upper limit It is also possible to adopt a configuration in which the differential pressure value and the lower limit differential pressure value are variably set so as to increase.

また、上述したように、アッシュは、再生処理での微粒子の燃え残りでもあるため、フィルタに捕集された微粒子の積算量が多いほどアッシュ堆積量は多くなる。そこで、フィルタのアッシュ堆積量に応じて上記上限差圧値及び下限差圧値を可変設定するに際しては、請求項３に記載の発明によるように、前記フィルタに捕集された微粒子の総積算量が多いほど、前記上限差圧値及び前記下限差圧値は大きくなるように可変設定される、といった構成を採用することもできる。 In addition, as described above, ash is also the remaining unburned fine particles in the regeneration process, so that the amount of accumulated ash increases as the integrated amount of fine particles collected by the filter increases. Therefore, when the upper limit differential pressure value and the lower limit differential pressure value are variably set in accordance with the ash accumulation amount of the filter, according to the invention of claim 3 , the total integrated amount of the fine particles collected in the filter It is also possible to adopt a configuration in which the upper limit differential pressure value and the lower limit differential pressure value are variably set so as to increase as the number increases.

請求項４に記載の発明は、請求項１〜３のいずれか１項に記載の内燃機関の排気浄化装置において、前記再生処理が終了した直後の前記圧力差が前記上限差圧値と前記下限差圧値との間の値ではなく、かつ前記ＮＯｘ浄化率が前記所定値よりも低いときには、前記フィルタに異常ありと判定することをその要旨とする。 According to a fourth aspect of the present invention, in the exhaust gas purification apparatus for an internal combustion engine according to any one of the first to third aspects, the pressure difference immediately after the regeneration process is completed is determined by the upper limit differential pressure value and the lower limit. The gist is to determine that the filter is abnormal when the NOx purification rate is not a value between the differential pressure values and lower than the predetermined value.

再生処理が終了した直後の上記圧力差が上記上限差圧値以上に大きいときには、フィルタを通過する排気の量が少なくなっているため、ＮＯｘ浄化触媒に流入する排気の流量が減少し、これにより同ＮＯｘ浄化触媒に供給される単位時間当たりの還元剤の量が不足してＮＯｘ浄化率が低下するおそれがある。また、再生処理が終了した直後の上記圧力差が上記下限差圧値以下に小さいときには、フィルタを通過する排気の量が多くなっているため、ＮＯｘ浄化触媒に流入する排気の流量が増大し、これにより同ＮＯｘ浄化触媒に貯留される還元剤の量が不足してＮＯｘ浄化率が低下するおそれがある。つまり、ＮＯｘ浄化率が所定値よりも低い場合であって、上記圧力差が上限差圧値と下限差圧値との間の値ではないときには、フィルタに異常が生じていると判定することができる。そこで、同構成では、再生処理が終了した直後の前記圧力差が前記上限差圧値と前記下限差圧値との間の値ではなく、かつ前記ＮＯｘ浄化率が前記所定値よりも低いときには、前記フィルタに異常ありと判定する、という構成を備えるようにしている。従って、分散板の異常のみならず、フィルタの異常をも判定することができるようになる。 When the pressure difference immediately after completion of the regeneration process is larger than the upper limit differential pressure value, the amount of exhaust gas passing through the filter is reduced, so the flow rate of exhaust gas flowing into the NOx purification catalyst is reduced. There is a risk that the amount of reducing agent per unit time supplied to the NOx purification catalyst will be insufficient and the NOx purification rate will decrease. Further, when the pressure difference immediately after the regeneration process is less than the lower limit differential pressure value, the amount of exhaust gas passing through the filter is increased, so the flow rate of exhaust gas flowing into the NOx purification catalyst increases, As a result, the amount of reducing agent stored in the NOx purification catalyst may be insufficient, and the NOx purification rate may be reduced. That is, when the NOx purification rate is lower than the predetermined value and the pressure difference is not a value between the upper limit differential pressure value and the lower limit differential pressure value, it is determined that an abnormality has occurred in the filter. it can. Therefore, in the same configuration, when the pressure difference immediately after the regeneration process is not a value between the upper limit differential pressure value and the lower limit differential pressure value, and the NOx purification rate is lower than the predetermined value, The filter is configured to determine that there is an abnormality. Accordingly, not only the abnormality of the dispersion plate but also the abnormality of the filter can be determined.

本発明にかかる内燃機関の排気浄化装置の第１実施形態について、これが適用される内燃機関及びその周辺構成を示す概略図。BRIEF DESCRIPTION OF THE DRAWINGS Schematic which shows the internal combustion engine to which this is applied, and its periphery structure about 1st Embodiment of the exhaust gas purification device of the internal combustion engine concerning this invention. 同実施形態にて実行される異常判定処理の手順を示すフローチャート。The flowchart which shows the procedure of the abnormality determination process performed in the same embodiment. 第２実施形態で実行される異常判定処理の手順を示すフローチャート。The flowchart which shows the procedure of the abnormality determination process performed in 2nd Embodiment. 第３実施形態で実行される異常判定処理の手順を示すフローチャート。The flowchart which shows the procedure of the abnormality determination process performed in 3rd Embodiment. 同実施形態において上限差圧値及び下限差圧値と走行距離との関係を示すグラフ。The graph which shows the relationship between an upper limit differential pressure value and a lower limit differential pressure value, and travel distance in the same embodiment.

（第１実施形態）
以下、この発明にかかる内燃機関の排気浄化装置を具体化した第１実施形態について、図１及び図２を参照して説明する。 (First embodiment)
A first embodiment of an internal combustion engine exhaust gas purification apparatus according to the present invention will be described below with reference to FIGS. 1 and 2.

図１に、本実施形態にかかる排気浄化装置が適用されたディーゼルエンジン（以下、単に「エンジン」という）、並びにそれらの周辺構成を示す概略構成図を示す。
エンジン１には複数の気筒＃１〜＃４が設けられている。シリンダヘッド２には複数の燃料噴射弁４ａ〜４ｄが取り付けられている。これら燃料噴射弁４ａ〜４ｄは各気筒＃１〜＃４の燃焼室に燃料を噴射する。また、シリンダヘッド２には新気を気筒内に導入するための吸気ポートと、燃焼ガスを気筒外へ排出するための排気ポート６ａ〜６ｄとが各気筒＃１〜＃４に対応して設けられている。 FIG. 1 is a schematic configuration diagram showing a diesel engine (hereinafter simply referred to as “engine”) to which the exhaust emission control device according to the present embodiment is applied, and a peripheral configuration thereof.
The engine 1 is provided with a plurality of cylinders # 1 to # 4. A plurality of fuel injection valves 4 a to 4 d are attached to the cylinder head 2. These fuel injection valves 4a to 4d inject fuel into the combustion chambers of the cylinders # 1 to # 4. Also, the cylinder head 2 is provided with intake ports for introducing fresh air into the cylinders and exhaust ports 6a to 6d for discharging combustion gas to the outside of the cylinders corresponding to the respective cylinders # 1 to # 4. It has been.

燃料噴射弁４ａ〜４ｄは、高圧燃料を蓄圧するコモンレール９に接続されている。コモンレール９はサプライポンプ１０に接続されている。サプライポンプ１０は燃料タンク内の燃料を吸入するとともにコモンレール９に高圧燃料を供給する。コモンレール９に供給された高圧燃料は、各燃料噴射弁４ａ〜４ｄの開弁時に同燃料噴射弁４ａ〜４ｄから気筒内に噴射される。   The fuel injection valves 4a to 4d are connected to a common rail 9 that accumulates high-pressure fuel. The common rail 9 is connected to the supply pump 10. The supply pump 10 sucks fuel in the fuel tank and supplies high-pressure fuel to the common rail 9. The high-pressure fuel supplied to the common rail 9 is injected into the cylinder from the fuel injection valves 4a to 4d when the fuel injection valves 4a to 4d are opened.

吸気ポートにはインテークマニホールド７が接続されている。インテークマニホールド７は吸気通路３に接続されている。この吸気通路３内には吸入空気量を調整するための吸気絞り弁１６が設けられている。   An intake manifold 7 is connected to the intake port. The intake manifold 7 is connected to the intake passage 3. An intake throttle valve 16 for adjusting the intake air amount is provided in the intake passage 3.

排気ポート６ａ〜６ｄにはエキゾーストマニホールド８が接続されている。エキゾーストマニホールド８は排気通路２６に接続されている。
排気通路２６の途中には、排気圧を利用して気筒に導入される吸入空気を過給するターボチャージャ１１が設けられている。同ターボチャージャ１１の吸気側コンプレッサと吸気絞り弁１６との間の吸気通路３にはインタークーラ１８が設けられている。このインタークーラ１８によって、ターボチャージャ１１の過給により温度上昇した吸入空気の冷却が図られる。 An exhaust manifold 8 is connected to the exhaust ports 6a to 6d. The exhaust manifold 8 is connected to the exhaust passage 26.
In the middle of the exhaust passage 26, there is provided a turbocharger 11 that supercharges intake air introduced into the cylinder using exhaust pressure. An intercooler 18 is provided in the intake passage 3 between the intake side compressor of the turbocharger 11 and the intake throttle valve 16. The intercooler 18 cools the intake air whose temperature has risen due to supercharging of the turbocharger 11.

また、排気通路２６の途中にあって、ターボチャージャ１１の排気側タービンの下流には、排気を浄化する第１浄化部材３０が設けられている。この第１浄化部材３０の内部には、排気の流れ方向に対して直列に酸化触媒３１及びフィルタ３２が配設されている。   A first purification member 30 that purifies the exhaust gas is provided in the middle of the exhaust passage 26 and downstream of the exhaust side turbine of the turbocharger 11. Inside the first purification member 30, an oxidation catalyst 31 and a filter 32 are arranged in series with respect to the flow direction of the exhaust gas.

酸化触媒３１には、排気中のＨＣを酸化処理する触媒が担持されている。また、フィルタ３２は、排気中のＰＭ（粒子状物質）を捕集する部材であって、多孔質のセラミックで構成されている。このフィルタ３２には、ＰＭの酸化を促進させるための触媒が担持されており、排気中のＰＭは、フィルタ３２の多孔質の壁を通過する際に捕集される。   The oxidation catalyst 31 carries a catalyst for oxidizing HC in the exhaust. The filter 32 is a member that collects PM (particulate matter) in the exhaust gas, and is made of porous ceramic. The filter 32 carries a catalyst for promoting the oxidation of PM, and the PM in the exhaust gas is collected when passing through the porous wall of the filter 32.

また、エキゾーストマニホールド８の集合部近傍には、酸化触媒３１やフィルタ３２に添加剤として燃料を供給するための燃料添加弁５が設けられている。この燃料添加弁５は、燃料供給管２７を介して前記サプライポンプ１０に接続されている。なお、燃料添加弁５の配設位置は、排気系にあって第１浄化部材３０の上流側であれば適宜変更するも可能である。   Further, a fuel addition valve 5 for supplying fuel as an additive to the oxidation catalyst 31 and the filter 32 is provided in the vicinity of the collecting portion of the exhaust manifold 8. The fuel addition valve 5 is connected to the supply pump 10 through a fuel supply pipe 27. The position of the fuel addition valve 5 can be changed as appropriate as long as it is in the exhaust system and upstream of the first purification member 30.

フィルタ３２に捕集されたＰＭの量（以下、ＰＭ堆積量ＰＭｓｍという）が所定値を超えると、フィルタ３２の再生処理が開始されて燃料添加弁５からはエキゾーストマニホールド８内に向けて燃料が噴射される。この燃料添加弁５から噴射された燃料は、酸化触媒３１に達すると燃焼され、これにより排気温度の上昇が図られる。そして、酸化触媒３１にて昇温された排気がフィルタ３２に流入することにより、同フィルタ３２は昇温され、これによりフィルタ３２に堆積したＰＭが酸化処理されてフィルタ３２の再生が図られる。そして、ＰＭ堆積量ＰＭｓｍが所定の再生終了値ＰＭｅ以下にまで減少すると、燃料添加弁５からの燃料噴射が終了されて、再生処理は終了される。   When the amount of PM trapped in the filter 32 (hereinafter referred to as PM accumulation amount PMsm) exceeds a predetermined value, regeneration processing of the filter 32 is started and fuel is supplied from the fuel addition valve 5 into the exhaust manifold 8. Be injected. The fuel injected from the fuel addition valve 5 is combusted when it reaches the oxidation catalyst 31, thereby increasing the exhaust temperature. The exhaust gas whose temperature has been raised by the oxidation catalyst 31 flows into the filter 32, whereby the temperature of the filter 32 is raised, whereby the PM deposited on the filter 32 is oxidized and the filter 32 is regenerated. Then, when the PM accumulation amount PMsm decreases to a predetermined regeneration end value PMe or less, the fuel injection from the fuel addition valve 5 is terminated and the regeneration process is terminated.

また、排気通路２６の途中にあって、第１浄化部材３０の下流には、排気を浄化する第２浄化部材４０が設けられている。第２浄化部材４０の内部には、還元剤を利用して排気中のＮＯｘを浄化するＮＯＸ浄化触媒として、選択還元型ＮＯｘ触媒（以下、ＳＣＲ触媒という）４１が配設されている。   A second purification member 40 that purifies the exhaust gas is provided in the middle of the exhaust passage 26 and downstream of the first purification member 30. A selective reduction type NOx catalyst (hereinafter referred to as SCR catalyst) 41 is disposed inside the second purification member 40 as a NOX purification catalyst that purifies NOx in the exhaust gas using a reducing agent.

さらに、排気通路２６の途中にあって、第２浄化部材４０の下流には、排気を浄化する第３浄化部材５０が設けられている。第３浄化部材５０の内部には、排気中のアンモニアを浄化するアンモニア酸化触媒５１が配設されている。   Further, a third purification member 50 for purifying exhaust gas is provided in the middle of the exhaust passage 26 and downstream of the second purification member 40. Inside the third purification member 50, an ammonia oxidation catalyst 51 for purifying ammonia in the exhaust is disposed.

エンジン１には、上記ＳＣＲ触媒４１に還元剤を供給する還元剤供給機構としての尿素水供給機構２００が設けられている。尿素水供給機構２００は、尿素水を貯留するタンク２１０、排気通路２６内に尿素水を噴射供給する尿素添加弁２３０、尿素添加弁２３０とタンク２１０とを接続する供給通路２４０、供給通路２４０の途中に設けられたポンプ２２０にて構成されている。   The engine 1 is provided with a urea water supply mechanism 200 as a reducing agent supply mechanism that supplies a reducing agent to the SCR catalyst 41. The urea water supply mechanism 200 includes a tank 210 that stores urea water, a urea addition valve 230 that injects urea water into the exhaust passage 26, a supply passage 240 that connects the urea addition valve 230 and the tank 210, and a supply passage 240. The pump 220 is provided in the middle.

尿素添加弁２３０は、第１浄化部材３０と第２浄化部材４０との間の排気通路２６に設けられており、その噴射孔はＳＣＲ触媒４１に向けられている。この尿素添加弁２３０が開弁されると、供給通路２４０を介して排気通路２６内に尿素水が噴射供給される。   The urea addition valve 230 is provided in the exhaust passage 26 between the first purification member 30 and the second purification member 40, and its injection hole is directed to the SCR catalyst 41. When the urea addition valve 230 is opened, urea water is injected and supplied into the exhaust passage 26 via the supply passage 240.

ポンプ２２０は電動式のポンプであり、正回転時には、タンク２１０から尿素添加弁２３０に向けて尿素水を送液する。一方、逆回転時には、尿素添加弁２３０からタンク２１０に向けて尿素水を送液する。つまり、ポンプ２２０の逆回転時には、尿素添加弁２３０及び供給通路２４０から尿素水が回収されてタンク２１０に戻される。   The pump 220 is an electric pump, and at the time of forward rotation, the urea water is fed from the tank 210 toward the urea addition valve 230. On the other hand, during reverse rotation, urea water is sent from the urea addition valve 230 toward the tank 210. In other words, during the reverse rotation of the pump 220, urea water is recovered from the urea addition valve 230 and the supply passage 240 and returned to the tank 210.

また、尿素添加弁２３０とＳＣＲ触媒４１との間の排気通路２６内には、尿素添加弁２３０から噴射された尿素水をＳＣＲ触媒４１の上流で分散させることにより同尿素水の霧化を促進する分散板６０が設けられている。   Further, in the exhaust passage 26 between the urea addition valve 230 and the SCR catalyst 41, the urea water injected from the urea addition valve 230 is dispersed upstream of the SCR catalyst 41 to promote atomization of the urea water. A dispersion plate 60 is provided.

尿素添加弁２３０から噴射された尿素水は、排気の熱によって加水分解されてアンモニアとなる。そしてこのアンモニアがＮＯｘの還元剤としてＳＣＲ触媒４１に供給される。ＳＣＲ触媒４１に供給されたアンモニアは、同ＳＣＲ触媒４１に吸蔵されてＮＯｘの還元に利用される。なお、加水分解されたアンモニアの一部は、ＳＣＲ触媒４１に吸蔵される前に直接ＮＯｘの還元に利用される。   The urea water injected from the urea addition valve 230 is hydrolyzed by the heat of the exhaust to become ammonia. The ammonia is supplied to the SCR catalyst 41 as a NOx reducing agent. Ammonia supplied to the SCR catalyst 41 is occluded by the SCR catalyst 41 and used for NOx reduction. A part of the hydrolyzed ammonia is directly used for NOx reduction before being occluded by the SCR catalyst 41.

この他、エンジン１には排気再循環装置（以下、ＥＧＲ装置という）が備えられている。このＥＧＲ装置は、排気の一部を吸入空気に導入することで気筒内の燃焼温度を低下させ、ＮＯｘの発生量を低減させる装置である。この排気再循環装置は、吸気通路３とエキゾーストマニホールド８とを連通するＥＧＲ通路１３、同ＥＧＲ通路１３に設けられたＥＧＲ弁１５、及びＥＧＲクーラ１４等により構成されている。ＥＧＲ弁１５の開度が調整されることにより排気通路２６から吸気通路３に導入される排気再循環量、すなわちＥＧＲ量が調量される。また、ＥＧＲクーラ１４によってＥＧＲ通路１３内を流れる排気の温度が低下される。   In addition, the engine 1 is provided with an exhaust gas recirculation device (hereinafter referred to as an EGR device). This EGR device is a device that reduces the combustion temperature in the cylinder by introducing a part of the exhaust gas into the intake air, thereby reducing the amount of NOx generated. This exhaust gas recirculation device includes an EGR passage 13 that communicates the intake passage 3 and the exhaust manifold 8, an EGR valve 15 provided in the EGR passage 13, an EGR cooler 14, and the like. By adjusting the opening degree of the EGR valve 15, the exhaust gas recirculation amount introduced into the intake passage 3 from the exhaust passage 26, that is, the EGR amount is adjusted. Further, the temperature of the exhaust gas flowing through the EGR passage 13 is lowered by the EGR cooler 14.

エンジン１には、機関運転状態を検出するための各種センサが取り付けられている。例えば、エアフロメータ１９は吸気通路３内の吸入空気量ＧＡを検出する。絞り弁開度センサ２０は吸気絞り弁１６の開度を検出する。機関回転速度センサ２１はクランクシャフトの回転速度、すなわち機関回転速度ＮＥを検出する。アクセルセンサ２２はアクセルペダルの踏み込み量、すなわちアクセル操作量ＡＣＣＰを検出する。外気温センサ２３は、外気温ＴＨｏｕｔを検出する。車速センサ２４はエンジン１が搭載された車両の車速ＳＰＤを検出する。イグニッションスイッチ２５は、車両の運転者によるエンジン１の始動操作及び停止操作を検出する。   Various sensors for detecting the engine operation state are attached to the engine 1. For example, the air flow meter 19 detects the intake air amount GA in the intake passage 3. The throttle valve opening sensor 20 detects the opening of the intake throttle valve 16. The engine rotation speed sensor 21 detects the rotation speed of the crankshaft, that is, the engine rotation speed NE. The accelerator sensor 22 detects an accelerator pedal depression amount, that is, an accelerator operation amount ACCP. The outside air temperature sensor 23 detects the outside air temperature THout. The vehicle speed sensor 24 detects the vehicle speed SPD of the vehicle on which the engine 1 is mounted. The ignition switch 25 detects a start operation and a stop operation of the engine 1 by a vehicle driver.

また、酸化触媒３１の上流に設けられた第１排気温度センサ１００は、酸化触媒３１に流入する前の排気温度である第１排気温度ＴＨ１を検出する。差圧センサ１１０は、フィルタ３２の上流及び下流の排気圧の圧力差である差圧ΔＰを検出する。第１浄化部材３０と第２浄化部材４０との間の排気通路２６にあって、尿素添加弁２３０の上流には、第２排気温度センサ１２０、第１ＮＯｘセンサ１３０、及び圧力センサ１５０が設けられている。第２排気温度センサ１２０は、ＳＣＲ触媒４１に流入する前の排気温度である第２排気温度ＴＨ２を検出する。第１ＮＯｘセンサ１３０は、ＳＣＲ触媒４１に流入する前の排気中のＮＯｘ濃度である第１ＮＯｘ濃度Ｎ１を検出する。圧力センサ１５０は、分散板６０よりも上流の排気圧である背圧Ｐを検出する。第３浄化部材５０の下流の排気通路２６には、ＳＣＲ触媒４１で浄化された排気のＮＯｘ濃度である第２ＮＯｘ濃度Ｎ２を検出する第２ＮＯｘセンサ１４０が設けられている。   The first exhaust temperature sensor 100 provided upstream of the oxidation catalyst 31 detects the first exhaust temperature TH1 that is the exhaust temperature before flowing into the oxidation catalyst 31. The differential pressure sensor 110 detects a differential pressure ΔP that is a pressure difference between the exhaust pressure upstream and downstream of the filter 32. A second exhaust temperature sensor 120, a first NOx sensor 130, and a pressure sensor 150 are provided in the exhaust passage 26 between the first purification member 30 and the second purification member 40 and upstream of the urea addition valve 230. ing. The second exhaust temperature sensor 120 detects a second exhaust temperature TH2, which is the exhaust temperature before flowing into the SCR catalyst 41. The first NOx sensor 130 detects a first NOx concentration N1, which is the NOx concentration in the exhaust before flowing into the SCR catalyst 41. The pressure sensor 150 detects a back pressure P that is an exhaust pressure upstream of the dispersion plate 60. The exhaust passage 26 downstream of the third purification member 50 is provided with a second NOx sensor 140 that detects a second NOx concentration N2 that is the NOx concentration of the exhaust purified by the SCR catalyst 41.

これら各種センサ等の出力は制御装置８０に入力される。この制御装置８０は、中央処理制御装置（ＣＰＵ）、各種プログラムやマップ等を予め記憶した読出専用メモリ（ＲＯＭ）、ＣＰＵの演算結果等を一時記憶するランダムアクセスメモリ（ＲＡＭ）、タイマカウンタ、入力インターフェース、出力インターフェース等を備えたマイクロコンピュータを中心に構成されている。   Outputs from these various sensors are input to the control device 80. The control device 80 includes a central processing control device (CPU), a read-only memory (ROM) that stores various programs and maps in advance, a random access memory (RAM) that temporarily stores CPU calculation results, a timer counter, an input The microcomputer is mainly configured with an interface, an output interface, and the like.

そして、この制御装置８０により、例えば燃料噴射弁４ａ〜４ｄや燃料添加弁５の燃料噴射量制御・燃料噴射時期制御、サプライポンプ１０の吐出圧力制御、吸気絞り弁１６を開閉するアクチュエータ１７の駆動量制御、ＥＧＲ弁１５の開度制御等、エンジン１の各種制御が行われる。また、上記フィルタ３２に捕集されたＰＭを燃焼させる上記再生処理等といった各種の排気浄化制御も同制御装置８０によって行われる。   Then, by this control device 80, for example, fuel injection amount control / fuel injection timing control of the fuel injection valves 4a to 4d and the fuel addition valve 5, discharge pressure control of the supply pump 10, and driving of the actuator 17 for opening and closing the intake throttle valve 16 Various controls of the engine 1 such as quantity control and opening control of the EGR valve 15 are performed. The exhaust gas purification control such as the regeneration process for burning the PM collected by the filter 32 is also performed by the controller 80.

また、制御装置８０は、排気浄化制御の一つとして、上記尿素添加弁２３０による尿素水の添加制御を行う。この添加制御では、エンジン１から排出されるＮＯｘを還元処理するために過不足の無い尿素添加量が機関運転状態等に基づいて算出され、その算出された尿素添加量が尿素添加弁２３０から噴射されるように、同尿素添加弁２３０の開弁状態が制御される。なお、ＮＯｘ還元のための上記尿素水添加は、機関運転中は継続して行われ、機関運転が停止されると停止される。   Further, the control device 80 performs urea water addition control by the urea addition valve 230 as one of exhaust purification control. In this addition control, a urea addition amount without excess or deficiency is calculated based on the engine operating state or the like in order to reduce the NOx discharged from the engine 1, and the calculated urea addition amount is injected from the urea addition valve 230. Thus, the valve opening state of the urea addition valve 230 is controlled. The urea water addition for NOx reduction is continuously performed during engine operation, and is stopped when the engine operation is stopped.

ところで、上述したように、分散板６０に変形などの異常が生じると、尿素水の霧化状態が変化するようになる。そのため、ＳＣＲ触媒４１に供給されるアンモニアの量が変化し、その結果、浄化されるＮＯｘの量、つまりＮＯｘ浄化率が低下するようになる。   By the way, as described above, when abnormality such as deformation occurs in the dispersion plate 60, the atomization state of the urea water changes. Therefore, the amount of ammonia supplied to the SCR catalyst 41 changes, and as a result, the amount of NOx to be purified, that is, the NOx purification rate is reduced.

そこで、制御装置８０は、図２に示す異常判定処理を所定周期毎に実行することで、ＮＯｘ浄化率が低下する原因の一つである分散板６０の異常を特定するようにしている。
本処理が開始されるとまず、第１ＮＯｘ濃度Ｎ１及び第２ＮＯｘ濃度Ｎ２からＮＯｘ浄化率Ｒが算出される（Ｓ１００）。ここでは、次式（１）からＮＯｘ浄化率Ｒが算出される。なお、本実施形態では、第１ＮＯｘ濃度Ｎ１及び第２ＮＯｘ濃度Ｎ２をセンサにて検出するようにしてもよいが、機関運転状態等に基づいて推定してもよい。 Therefore, the control device 80 performs the abnormality determination process shown in FIG. 2 at predetermined intervals to identify an abnormality of the dispersion plate 60 that is one of the causes of the NOx purification rate decreasing.
When this process is started, first, the NOx purification rate R is calculated from the first NOx concentration N1 and the second NOx concentration N2 (S100). Here, the NOx purification rate R is calculated from the following equation (1). In the present embodiment, the first NOx concentration N1 and the second NOx concentration N2 may be detected by a sensor, but may be estimated based on the engine operating state or the like.


Ｒ＝（Ｎ１−Ｎ２）／Ｎ１ …（１）
Ｒ：ＮＯｘ浄化率
Ｎ１：第１ＮＯｘ濃度
Ｎ２：第２ＮＯｘ濃度

次に、ＮＯｘ浄化率Ｒが浄化率判定値αよりも小さいか否かが判定される（Ｓ１１０）。そして、ＮＯｘ浄化率Ｒが浄化率判定値α以上であるときには（Ｓ１１０：ＮＯ）、ＮＯｘの浄化が正常に行われていると判断されて、本処理は一旦終了される。
R = (N1-N2) / N1 (1)
R: NOx purification rate N1: First NOx concentration N2: Second NOx concentration

Next, it is determined whether or not the NOx purification rate R is smaller than the purification rate determination value α (S110). When the NOx purification rate R is equal to or greater than the purification rate determination value α (S110: NO), it is determined that NOx purification is normally performed, and this process is temporarily terminated.

一方、ＮＯｘ浄化率Ｒが浄化率判定値αよりも小さいときには（Ｓ１１０：ＹＥＳ）、分散板６０の上流の排気圧である背圧Ｐが、上限背圧値Ｐｍａｘと下限背圧値Ｐｍｉｎとの間の値となっているか否かが判定される（Ｓ１２０）。この上限背圧値Ｐｍａｘは、予め定められた上限圧力値である。より具体的には、分散板６０の変形や分散板６０への異物付着等による圧力損失の増大に伴い、背圧Ｐが異常に高くなったときの圧力値が設定されている。   On the other hand, when the NOx purification rate R is smaller than the purification rate determination value α (S110: YES), the back pressure P that is the exhaust pressure upstream of the dispersion plate 60 is equal to the upper limit back pressure value Pmax and the lower limit back pressure value Pmin. It is determined whether the value is between (S120). This upper limit back pressure value Pmax is a predetermined upper limit pressure value. More specifically, a pressure value when the back pressure P becomes abnormally high with an increase in pressure loss due to deformation of the dispersion plate 60 or adhesion of foreign matter to the dispersion plate 60 is set.

また、下限背圧値Ｐｍｉｎも予め定められた下限圧力値である。より具体的には、分散板６０の変形や分散板６０の破損等による圧力損失の低下に伴い、背圧Ｐが異常に低くなったときの圧力値が設定されている。   The lower limit back pressure value Pmin is also a predetermined lower limit pressure value. More specifically, a pressure value is set when the back pressure P becomes abnormally low as pressure loss decreases due to deformation of the dispersion plate 60, breakage of the dispersion plate 60, or the like.

そして、背圧Ｐが、上限背圧値Ｐｍａｘと下限背圧値Ｐｍｉｎとの間の値になっているとき、つまり「Ｐｍｉｎ＜Ｐ＜Ｐｍａｘ」が成立するときには（Ｓ１２０：ＹＥＳ）、分散板６０が正常であると判断されて、本処理は一旦終了される。   When the back pressure P is a value between the upper limit back pressure value Pmax and the lower limit back pressure value Pmin, that is, when “Pmin <P <Pmax” is satisfied (S120: YES), the dispersion plate 60 Is determined to be normal, the process is temporarily terminated.

一方、背圧Ｐが、上限背圧値Ｐｍａｘと下限背圧値Ｐｍｉｎとの間の値になっていないとき、つまり「Ｐｍｉｎ≧Ｐ」または「Ｐ≧Ｐｍａｘ」が成立するときには（Ｓ１２０：ＮＯ）、分散板６０に異常有りと判定されて（Ｓ１３０）、本処理は一旦終了される。なお、ステップＳ１３０にて、分散板６０に異常有りと判定された場合には、警告灯の点灯等を行うことで車両の運転者に異常の発生が報知される。   On the other hand, when the back pressure P is not between the upper limit back pressure value Pmax and the lower limit back pressure value Pmin, that is, when “Pmin ≧ P” or “P ≧ Pmax” is satisfied (S120: NO). Then, it is determined that there is an abnormality in the dispersion plate 60 (S130), and this process is temporarily terminated. If it is determined in step S130 that there is an abnormality in the dispersion plate 60, the vehicle driver is notified of the occurrence of the abnormality by turning on a warning lamp or the like.

次に、本実施形態の作用を説明する。
分散板６０に異常が生じると、当該分散板６０の圧力損失が変化するため、分散板６０よりも上流の排気圧である背圧Ｐは、正常時とは異なった異常な値となる。ここで、背圧Ｐの異常値は、排気系を構成する他の部材での圧力損失が変化した場合にも生じる。例えば、フィルタ３２のＰＭ堆積量ＰＭｓｍの変化や、排気通路２６の内壁に対する異物付着等によっても圧力損失は変化する。しかし、分散板６０の異常とＮＯｘ浄化率Ｒの低下とは高い関連性があるため、ＮＯｘ浄化率Ｒの低下と背圧Ｐの異常値とがともに生じているときには、分散板６０に異常が生じている可能性が非常に高い。 Next, the operation of this embodiment will be described.
When an abnormality occurs in the dispersion plate 60, the pressure loss of the dispersion plate 60 changes. Therefore, the back pressure P, which is the exhaust pressure upstream of the dispersion plate 60, has an abnormal value different from that in the normal state. Here, the abnormal value of the back pressure P also occurs when pressure loss in other members constituting the exhaust system changes. For example, the pressure loss also changes due to a change in the PM accumulation amount PMsm of the filter 32 or adhesion of foreign matter to the inner wall of the exhaust passage 26. However, since there is a high correlation between the abnormality of the dispersion plate 60 and the decrease in the NOx purification rate R, when both the decrease in the NOx purification rate R and the abnormal value of the back pressure P occur, the abnormality is present in the dispersion plate 60. It is very likely that it has occurred.

そこで、上記異常判定処理では、ＮＯｘ浄化率Ｒが浄化率判定値αよりも低く（ステップＳ１１０での肯定判定）、かつ背圧Ｐが予め定められた上限背圧値Ｐｍａｘと下限背圧値Ｐｍｉｎとの間の値ではない異常値のときには（ステップＳ１２０での否定判定）、分散板６０に異常ありと判定される。従って、ＮＯｘ浄化率Ｒが低下する原因の一つである分散板６０の異常を特定することができる。   Therefore, in the abnormality determination process, the NOx purification rate R is lower than the purification rate determination value α (affirmative determination in step S110), and the back pressure P is a predetermined upper limit back pressure value Pmax and lower limit back pressure value Pmin. When the abnormal value is not a value between (a negative determination in step S120), it is determined that the dispersion plate 60 is abnormal. Therefore, it is possible to identify the abnormality of the dispersion plate 60, which is one of the causes that the NOx purification rate R decreases.

以上説明したように、本実施形態によれば、以下の効果を得ることができる。
（１）ＮＯｘ浄化率Ｒが浄化率判定値αよりも低く、かつ背圧Ｐが予め定められた上限背圧値Ｐｍａｘと下限背圧値Ｐｍｉｎとの間の値ではない異常値のときには、分散板６０に異常ありと判定するようにしている。従って、ＮＯｘ浄化率Ｒが低下する原因の一つである分散板６０の異常を特定することができるようになる。
（第２実施形態）
次に、本発明にかかる内燃機関の排気浄化装置を具体化した第２実施形態について、図３を参照して説明する。 As described above, according to the present embodiment, the following effects can be obtained.
(1) When the NOx purification rate R is lower than the purification rate determination value α and the back pressure P is an abnormal value that is not a value between the predetermined upper limit back pressure value Pmax and the lower limit back pressure value Pmin, dispersion The plate 60 is determined to be abnormal. Therefore, it is possible to identify the abnormality of the dispersion plate 60, which is one of the causes that the NOx purification rate R is reduced.
(Second Embodiment)
Next, a second embodiment of the internal combustion engine exhaust gas purification apparatus according to the present invention will be described with reference to FIG.

フィルタ３２が上記圧力センサ１５０の上流に設けられている場合、フィルタ３２でのＰＭ堆積量が圧力センサ１５０で検出される背圧Ｐに影響を与える。従って、背圧Ｐに基づく分散板６０の異常判定を行うに際して、ＰＭ堆積量の影響による背圧Ｐの変化を、分散板６０の異常による背圧Ｐの変化であると誤って判定するおそれがある。   When the filter 32 is provided upstream of the pressure sensor 150, the amount of PM accumulated on the filter 32 affects the back pressure P detected by the pressure sensor 150. Therefore, when the abnormality determination of the dispersion plate 60 based on the back pressure P is performed, there is a possibility that the change of the back pressure P due to the influence of the PM accumulation amount is erroneously determined as the change of the back pressure P due to the abnormality of the dispersion plate 60. is there.

そこで、本実施形態では、こうしたＰＭ堆積量が分散板６０の異常判定に与える影響を抑えるようにしており、第１実施形態で説明した異常判定処理に対して、図３に示すように新たなステップＳ２００及びステップＳ２１０の処理を追加するようにしている。   Therefore, in the present embodiment, the effect of the PM accumulation amount on the abnormality determination of the dispersion plate 60 is suppressed, and a new one as shown in FIG. 3 is provided for the abnormality determination process described in the first embodiment. Steps S200 and S210 are added.

そこで、以下では、第１実施形態との相異点を中心にして、本実施形態における異常判定処理を説明する。
図３に示す本実施形態の異常判定処理も、制御装置８０によって所定周期毎に実行される。なお、図３において先の図２で説明した処理ステップと同じ処理ステップには、同一のステップ番号を付している。 Therefore, hereinafter, the abnormality determination process in the present embodiment will be described focusing on the differences from the first embodiment.
The abnormality determination process of this embodiment shown in FIG. 3 is also executed by the control device 80 at predetermined intervals. In FIG. 3, the same processing steps as those described in FIG.

本処理が開始されるとまず、第１ＮＯｘ濃度Ｎ１及び第２ＮＯｘ濃度Ｎ２からＮＯｘ浄化率Ｒが算出される（Ｓ１００）。
次に、フィルタ３２の再生処理の終了直後であり、かつＰＭ堆積量ＰＭｓｍが判定値Ａよりも少ないか否かが判定される（Ｓ２００）。なお、通常であれば、再生処理が終了した直後のＰＭ堆積量ＰＭｓｍは十分に少なくなっている。しかし、再生処理の終了が、同再生処理の中断等によるものであった場合には、再生処理が終了した直後のＰＭ堆積量ＰＭｓｍは十分に少なくなっておらず、ＰＭ堆積量ＰＭｓｍの減少が不完全な状態になっているおそれがある。そこで、上記判定値Ａとしては、ＰＭ堆積量ＰＭｓｍが十分に少なくなっていることを判定できる値が設定されており、例えば本実施形態では上記再生終了値ＰＭｅと同じ値が設定されている。なお、ＰＭ堆積量ＰＭｓｍと判定値Ａとの比較は、必ずしも行う必要はなく、適宜省略することもできる。 When this process is started, first, the NOx purification rate R is calculated from the first NOx concentration N1 and the second NOx concentration N2 (S100).
Next, it is determined immediately after the end of the regeneration process of the filter 32 and whether the PM accumulation amount PMsm is smaller than the determination value A (S200). Normally, the PM deposition amount PMsm immediately after the regeneration process is completed is sufficiently small. However, when the end of the regeneration process is due to the interruption of the regeneration process or the like, the PM deposition amount PMsm immediately after the regeneration process ends is not sufficiently reduced, and the PM deposition amount PMsm decreases. There may be an incomplete state. Therefore, as the determination value A, a value that can determine that the PM accumulation amount PMsm is sufficiently small is set. For example, in the present embodiment, the same value as the regeneration end value PMe is set. Note that comparison of the determination value A and the PM accumulation amount PMsm is not necessary to perform always, or may be omitted as appropriate.

そして、フィルタ３２の再生処理の終了直後ではない、またはＰＭ堆積量ＰＭｓｍが判定値Ａ以上であるときには（Ｓ２００：ＮＯ）、本処理は一旦終了される。
一方、フィルタ３２の再生処理の終了直後であり、かつＰＭ堆積量ＰＭｓｍが判定値Ａよりも少ないときには（Ｓ２００：ＹＥＳ）、フィルタ３２の上流及び下流の排気圧の圧力差であって、フィルタ３２の再生処理の終了直後における差圧ΔＰが、上限差圧値ΔＰｍａｘと下限差圧値ΔＰｍｉｎとの間の値になっているか否かが判定される（Ｓ２１０）。 Then, when not immediately after the end of the regeneration process of the filter 32, or when the PM accumulation amount PMsm is greater than or equal to the determination value A (S200: NO), this process is temporarily ended.
On the other hand, immediately after the regeneration processing of the filter 32 is completed and the PM accumulation amount PMsm is smaller than the determination value A (S200: YES), the pressure difference between the upstream and downstream exhaust pressures of the filter 32 is obtained. It is determined whether or not the differential pressure ΔP immediately after the end of the regeneration process is a value between the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin (S210).

この上限差圧値ΔＰｍａｘは、予めの実験等を通じて定められた値である。より具体的には、フィルタ３２のＰＭ堆積量ＰＭｓｍが過剰に多いときや、エンジン１からの微粒子排出量が過剰に多いとき、あるいは上記再生処理が十分に行われていないときには、フィルタ３２の圧力損失が過剰に高くなるため、差圧ΔＰが過度に大きくなる。このように差圧ΔＰが過度に大きいときの値が、上限差圧値ΔＰｍａｘとして設定されている。   The upper limit differential pressure value ΔPmax is a value determined through a prior experiment or the like. More specifically, when the PM deposition amount PMsm of the filter 32 is excessively large, when the particulate discharge amount from the engine 1 is excessively large, or when the regeneration process is not sufficiently performed, the pressure of the filter 32 is increased. Since the loss becomes excessively high, the differential pressure ΔP becomes excessively large. Thus, the value when the differential pressure ΔP is excessively large is set as the upper limit differential pressure value ΔPmax.

また、下限差圧値ΔＰｍｉｎも予めの実験等を通じて定められた値である。より具体的には、溶損等の発生によりフィルタ３２の圧力損失が過剰に低くなると、差圧ΔＰが過度に小さくなる。このように差圧ΔＰが過度に小さいときの値が、下限差圧値ΔＰｍｉｎとして設定されている。   The lower limit differential pressure value ΔPmin is also a value determined through a prior experiment or the like. More specifically, if the pressure loss of the filter 32 becomes excessively low due to the occurrence of melting damage or the like, the differential pressure ΔP becomes excessively small. Thus, the value when the differential pressure ΔP is excessively small is set as the lower limit differential pressure value ΔPmin.

そして、差圧ΔＰが、上限差圧値ΔＰｍａｘと下限差圧値ΔＰｍｉｎとの間の値になっていないとき、つまり「ΔＰｍｉｎ≧ΔＰ」または「ΔＰ≧ΔＰｍａｘ」が成立するときには（Ｓ２１０：ＮＯ）、ＮＯｘ浄化率Ｒ及び背圧Ｐに基づいた分散板６０の異常判定を行うことなく、本処理は一旦終了される。つまり、ステップＳ２１０にて否定判定されるときには、分散板６０の異常判定が禁止される。   When the differential pressure ΔP is not a value between the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin, that is, when “ΔPmin ≧ ΔP” or “ΔP ≧ ΔPmax” is satisfied (S210: NO). The present process is temporarily terminated without determining the abnormality of the dispersion plate 60 based on the NOx purification rate R and the back pressure P. That is, when a negative determination is made in step S210, abnormality determination of the dispersion plate 60 is prohibited.

一方、差圧ΔＰが、上限差圧値ΔＰｍａｘと下限差圧値ΔＰｍｉｎとの間の値になっているとき、つまり「ΔＰｍｉｎ＜ΔＰ＜ΔＰｍａｘ」が成立するときには（Ｓ２１０：ＹＥＳ）、ＮＯｘ浄化率Ｒが浄化率判定値αよりも小さいか否かが判定される（Ｓ１１０）。そして、ＮＯｘ浄化率Ｒが浄化率判定値α以上であるときには（Ｓ１１０：ＮＯ）、ＮＯｘの浄化が正常に行われていると判断されて、本処理は一旦終了される。   On the other hand, when the differential pressure ΔP is a value between the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin, that is, when “ΔPmin <ΔP <ΔPmax” is satisfied (S210: YES), the NOx purification rate. It is determined whether or not R is smaller than the purification rate determination value α (S110). When the NOx purification rate R is equal to or greater than the purification rate determination value α (S110: NO), it is determined that NOx purification is normally performed, and this process is temporarily terminated.

一方、ＮＯｘ浄化率Ｒが浄化率判定値αよりも小さいときには（Ｓ１１０：ＹＥＳ）、分散板６０の上流の排気圧である背圧Ｐが、上限背圧値Ｐｍａｘと下限背圧値Ｐｍｉｎとの間の値となっているか否かが判定される（Ｓ１２０）。なお、このときの背圧Ｐは、ステップＳ２００にて肯定判定されているため、フィルタ３２の再生処理の終了直後における背圧Ｐとなっている。   On the other hand, when the NOx purification rate R is smaller than the purification rate determination value α (S110: YES), the back pressure P that is the exhaust pressure upstream of the dispersion plate 60 is equal to the upper limit back pressure value Pmax and the lower limit back pressure value Pmin. It is determined whether the value is between (S120). Note that the back pressure P at this time is determined to be affirmative in step S <b> 200, and thus is the back pressure P immediately after the end of the regeneration process of the filter 32.

そして、背圧Ｐが、上限背圧値Ｐｍａｘと下限背圧値Ｐｍｉｎとの間の値になっているとき、つまり「Ｐｍｉｎ＜Ｐ＜Ｐｍａｘ」が成立するときには（Ｓ１２０：ＹＥＳ）、分散板６０が正常であると判断されて、本処理は一旦終了される。   When the back pressure P is a value between the upper limit back pressure value Pmax and the lower limit back pressure value Pmin, that is, when “Pmin <P <Pmax” is satisfied (S120: YES), the dispersion plate 60 Is determined to be normal, the process is temporarily terminated.

一方、背圧Ｐが、上限背圧値Ｐｍａｘと下限背圧値Ｐｍｉｎとの間の値になっていないとき、つまり「Ｐｍｉｎ≧Ｐ」または「Ｐ≧Ｐｍａｘ」が成立するときには（Ｓ１２０：ＮＯ）、分散板６０に異常有りと判定されて（Ｓ１３０）、本処理は一旦終了される。なお、ステップＳ１３０にて、分散板６０に異常有りと判定された場合には、警告灯の点灯等を行うことで車両の運転者に異常の発生が報知される。   On the other hand, when the back pressure P is not between the upper limit back pressure value Pmax and the lower limit back pressure value Pmin, that is, when “Pmin ≧ P” or “P ≧ Pmax” is satisfied (S120: NO). Then, it is determined that there is an abnormality in the dispersion plate 60 (S130), and this process is temporarily terminated. If it is determined in step S130 that there is an abnormality in the dispersion plate 60, the vehicle driver is notified of the occurrence of the abnormality by turning on a warning lamp or the like.

次に、本実施形態特有の作用を説明する。
本実施形態の異常判定処理では、ステップＳ２００にてフィルタ３２の再生処理の終了直後であるか否かを判定するようにしている。そして、ステップＳ１２０にて背圧Ｐを比較判定するときには、フィルタ３２の再生処理が終了した直後、つまりＰＭ堆積量ＰＭｓｍが非常に少なくなっているときの背圧Ｐを用いて比較判定が行われる。そのため、分散板６０の異常判定を行うに際して、ＰＭ堆積量の影響を極力抑えることができ、これにより分散板６０の異常判定の精度が高まるようになる。 Next, operations unique to the present embodiment will be described.
In the abnormality determination process of this embodiment, it is determined whether or not it is immediately after the end of the regeneration process of the filter 32 in step S200. When the back pressure P is compared and determined in step S120, the comparison determination is performed using the back pressure P immediately after the regeneration processing of the filter 32 is completed, that is, when the PM accumulation amount PMsm is very small. . Therefore, when determining the abnormality of the dispersion plate 60, it is possible to suppress the influence of the PM accumulation amount as much as possible, thereby increasing the accuracy of the abnormality determination of the dispersion plate 60.

また、フィルタ３２でのＰＭ堆積量が過剰に多いときや、エンジン１からのＰＭ排出量が過剰に多いとき、あるいは上記再生処理が十分に行われていないときには、フィルタ３２の圧力損失が過剰に高くなるため、上記差圧ΔＰが大きくなる。一方、溶損等の発生によりフィルタ３２の圧力損失が過剰に低くなると、上記差圧ΔＰは小さくなる。   Further, when the amount of accumulated PM in the filter 32 is excessively large, when the amount of PM discharged from the engine 1 is excessively large, or when the regeneration process is not sufficiently performed, the pressure loss of the filter 32 is excessively large. Therefore, the differential pressure ΔP increases. On the other hand, when the pressure loss of the filter 32 becomes excessively low due to the occurrence of melting damage or the like, the differential pressure ΔP becomes small.

こうしたフィルタ３２の圧力損失の変化は、フィルタ３２の下流にある圧力センサ１５０の検出値に影響を与える。そのため、フィルタ３２の圧力損失の異常による背圧Ｐの過度な上昇、あるいは過度な低下を分散板６０の異常と誤判定してしまうおそれがある。この点、本実施形態の異常判定処理では、再生処理が終了した直後の差圧ΔＰが上限差圧値ΔＰｍａｘと下限差圧値ΔＰｍｉｎとの間の値ではない、つまりフィルタ３２の圧力損失が過剰に変化しており異常があるときには、背圧Ｐ等に基づく分散板６０の異常判定が禁止される。そのため、分散板６０の異常判定を行うに際して、フィルタ３２の圧力損失の異常による悪影響が極力抑えられ、分散板６０の異常判定の精度が高くなる。   Such a change in the pressure loss of the filter 32 affects the detection value of the pressure sensor 150 downstream of the filter 32. Therefore, there is a possibility that an excessive increase or an excessive decrease in the back pressure P due to an abnormality in the pressure loss of the filter 32 may be erroneously determined as an abnormality in the dispersion plate 60. In this regard, in the abnormality determination process of the present embodiment, the differential pressure ΔP immediately after the regeneration process is finished is not a value between the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin, that is, the pressure loss of the filter 32 is excessive. When there is an abnormality, the abnormality determination of the dispersion plate 60 based on the back pressure P or the like is prohibited. Therefore, when the abnormality determination of the dispersion plate 60 is performed, the adverse effect due to the pressure loss abnormality of the filter 32 is suppressed as much as possible, and the accuracy of the abnormality determination of the dispersion plate 60 is increased.

以上説明したように、本実施形態によれば、第１実施形態の効果に加えて、さらに次の効果を得ることができる。
（２）フィルタ３２の再生処理が終了した直後の背圧Ｐに基づき、分散板６０の異常判定を行うようにしている。そのため、分散板６０の異常判定を行うに際して、フィルタ３２のＰＭ堆積量の影響を極力抑えることができ、これにより分散板６０の異常判定の精度を高めることができる。 As described above, according to the present embodiment, in addition to the effects of the first embodiment, the following effects can be further obtained.
(2) The abnormality determination of the dispersion plate 60 is performed based on the back pressure P immediately after the regeneration processing of the filter 32 is completed. Therefore, when the abnormality determination of the dispersion plate 60 is performed, the influence of the PM accumulation amount of the filter 32 can be suppressed as much as possible, thereby improving the accuracy of the abnormality determination of the dispersion plate 60.

（３）フィルタ３２の再生処理が終了した直後の差圧ΔＰが上限差圧値ΔＰｍａｘと下限差圧値ΔＰｍｉｎとの間の値でないときには、分散板６０の異常判定を禁止するようにしている。そのため、分散板６０の異常判定を行うに際して、フィルタ３２の圧力損失の異常による悪影響を極力抑えることができ、これにより分散板６０の異常判定の精度を高めることができる。
（第３実施形態）
次に、本発明にかかる内燃機関の排気浄化装置を具体化した第３実施形態について、図４及び図５を参照して説明する。 (3) When the differential pressure ΔP immediately after the regeneration processing of the filter 32 is not a value between the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin, the abnormality determination of the dispersion plate 60 is prohibited. Therefore, when the abnormality determination of the dispersion plate 60 is performed, an adverse effect due to the abnormality of the pressure loss of the filter 32 can be suppressed as much as possible, thereby improving the accuracy of the abnormality determination of the dispersion plate 60.
(Third embodiment)
Next, a third embodiment in which the exhaust gas purification apparatus for an internal combustion engine according to the present invention is embodied will be described with reference to FIGS.

上記第２実施形態では、差圧ΔＰが所定の範囲外の値であるかどうかを判定するために上記上限差圧値ΔＰｍａｘと上記下限差圧値ΔＰｍｉｎとを設定するようにした。
ここで、フィルタ３２には、潤滑油に由来する成分であって上述した再生処理による燃焼が困難なアッシュが堆積していくことが知られている。なお、このアッシュとしては、例えば潤滑油の添加剤等に含まれる成分（Ｚｎ、Ｃａ、Ｍｇ、Ｎａ等の金属成分など）が挙げられる。そして、再生処理が終了した直後の上記差圧ΔＰは、アッシュの堆積量によっても変化する。従って、こうしたアッシュ堆積量による差圧ΔＰの変化を考慮して、上限差圧値ΔＰｍａｘと下限差圧値ΔＰｍｉｎとを設定することが望ましい。そこで、本実施形態では、フィルタ３２のアッシュ堆積量に応じて上限差圧値ΔＰｍａｘと下限差圧値ΔＰｍｉｎとを可変設定するようにしている。 In the second embodiment, the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin are set in order to determine whether or not the differential pressure ΔP is outside the predetermined range.
Here, it is known that ash that is a component derived from lubricating oil and difficult to burn by the above-described regeneration process accumulates on the filter 32. In addition, as this ash, the component (metal components, such as Zn, Ca, Mg, Na, etc.) contained in the additive etc. of lubricating oil, etc. are mentioned, for example. The differential pressure ΔP immediately after the regeneration process is finished also changes depending on the amount of ash accumulated. Therefore, it is desirable to set the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin in consideration of such a change in the differential pressure ΔP due to the ash deposition amount. Therefore, in the present embodiment, the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin are variably set according to the ash accumulation amount of the filter 32.

以下、第３実施形態との相異点を中心にして、本実施形態における異常判定処理を説明する。
図４に示す本実施形態の異常判定処理も、制御装置８０によって所定周期毎に実行される。なお、図４において先の図２や図３で説明した処理ステップと同じ処理ステップには、同一のステップ番号を付している。 Hereinafter, the abnormality determination process in the present embodiment will be described focusing on the differences from the third embodiment.
The abnormality determination process of this embodiment shown in FIG. 4 is also executed by the control device 80 at predetermined intervals. In FIG. 4, the same step numbers are assigned to the same processing steps as those described in FIG. 2 and FIG.

本処理が開始されるとまず、第１ＮＯｘ濃度Ｎ１及び第２ＮＯｘ濃度Ｎ２からＮＯｘ浄化率Ｒが算出される（Ｓ１００）。
次に、フィルタ３２の再生処理の終了直後であり、かつＰＭ堆積量ＰＭｓｍが判定値Ａよりも少ないか否かが判定される（Ｓ２００）。 When this process is started, first, the NOx purification rate R is calculated from the first NOx concentration N1 and the second NOx concentration N2 (S100).
Next, it is determined immediately after the end of the regeneration process of the filter 32 and whether the PM accumulation amount PMsm is smaller than the determination value A (S200).

そして、フィルタ３２の再生処理の終了直後ではない、またはＰＭ堆積量ＰＭｓｍが判定値Ａ以上であるときには（Ｓ２００：ＮＯ）、本処理は一旦終了される。
一方、フィルタ３２の再生処理の終了直後であり、かつＰＭ堆積量ＰＭｓｍが判定値Ａよりも少ないときには（Ｓ２００：ＹＥＳ）、エンジン１を搭載した車両の総走行距離ＴＲに基づいて上限差圧値ΔＰｍａｘ及び下限差圧値ΔＰｍｉｎが算出される（Ｓ３００）。ここでの上限差圧値ΔＰｍａｘ及び下限差圧値ΔＰｍｉｎは、第２実施形態で説明した上限差圧値ΔＰｍａｘ及び下限差圧値ΔＰｍｉｎに準じたものである。ただし、本実施形態では、フィルタ３２のアッシュ堆積量による差圧ΔＰの変化を考慮して、上限差圧値ΔＰｍａｘ及び下限差圧値ΔＰｍｉｎは可変設定される。 Then, when not immediately after the end of the regeneration process of the filter 32, or when the PM accumulation amount PMsm is greater than or equal to the determination value A (S200: NO), this process is temporarily ended.
On the other hand, when the regeneration process of the filter 32 is completed and the PM accumulation amount PMsm is smaller than the determination value A (S200: YES), the upper limit differential pressure value is based on the total travel distance TR of the vehicle on which the engine 1 is mounted. ΔPmax and the lower limit differential pressure value ΔPmin are calculated (S300). The upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin here are based on the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin described in the second embodiment. However, in the present embodiment, the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin are variably set in consideration of a change in the differential pressure ΔP due to the ash accumulation amount of the filter 32.

ここで、アッシュ堆積量が多くなるほど上記差圧ΔＰは大きくなるため、アッシュ堆積量が多くなるほど上限差圧値ΔＰｍａｘ及び下限差圧値ΔＰｍｉｎを大きくすることが望ましい。そして、アッシュ堆積量は、車両の総走行距離ＴＲが長くなるほど多くなる。そこで、図５に示すように、総走行距離ＴＲが長いほど、上限差圧値ΔＰｍａｘ及び下限差圧値ΔＰｍｉｎは大きくなるように、同総走行距離ＴＲに基づいて可変設定される。   Here, since the differential pressure ΔP increases as the ash deposition amount increases, it is desirable to increase the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin as the ash deposition amount increases. The ash accumulation amount increases as the total travel distance TR of the vehicle increases. Therefore, as shown in FIG. 5, the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin are variably set based on the total travel distance TR as the total travel distance TR is longer.

こうして上限差圧値ΔＰｍａｘ及び下限差圧値ΔＰｍｉｎが設定されると、フィルタ３２の再生処理の終了直後における差圧ΔＰが、上限差圧値ΔＰｍａｘと下限差圧値ΔＰｍｉｎとの間の値になっているか否かが判定される（Ｓ２１０）。   When the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin are thus set, the differential pressure ΔP immediately after the end of the regeneration process of the filter 32 becomes a value between the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin. It is determined whether or not (S210).

そして、差圧ΔＰが、上限差圧値ΔＰｍａｘと下限差圧値ΔＰｍｉｎとの間の値になっているとき、つまり「ΔＰｍｉｎ＜ΔＰ＜ΔＰｍａｘ」が成立するときには（Ｓ２１０：ＹＥＳ）、ＮＯｘ浄化率Ｒが浄化率判定値αよりも小さいか否かが判定される（Ｓ１１０）。そして、ＮＯｘ浄化率Ｒが浄化率判定値α以上であるときには（Ｓ１１０：ＮＯ）、ＮＯｘの浄化が正常に行われていると判断されて、本処理は一旦終了される。   When the differential pressure ΔP is a value between the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin, that is, when “ΔPmin <ΔP <ΔPmax” is satisfied (S210: YES), the NOx purification rate. It is determined whether or not R is smaller than the purification rate determination value α (S110). When the NOx purification rate R is equal to or greater than the purification rate determination value α (S110: NO), it is determined that NOx purification is normally performed, and this process is temporarily terminated.

一方、ＮＯｘ浄化率Ｒが浄化率判定値αよりも小さいときには（Ｓ１１０：ＹＥＳ）、分散板６０の上流の排気圧である背圧Ｐが、上限背圧値Ｐｍａｘと下限背圧値Ｐｍｉｎとの間の値となっているか否かが判定される（Ｓ１２０）。なお、このときの背圧Ｐは、ステップＳ２００にて肯定判定されているため、フィルタ３２の再生処理の終了直後における背圧Ｐとなっている。   On the other hand, when the NOx purification rate R is smaller than the purification rate determination value α (S110: YES), the back pressure P that is the exhaust pressure upstream of the dispersion plate 60 is equal to the upper limit back pressure value Pmax and the lower limit back pressure value Pmin. It is determined whether the value is between (S120). Note that the back pressure P at this time is determined to be affirmative in step S <b> 200, and thus is the back pressure P immediately after the end of the regeneration process of the filter 32.

そして、背圧Ｐが、上限背圧値Ｐｍａｘと下限背圧値Ｐｍｉｎとの間の値になっているとき、つまり「Ｐｍｉｎ＜Ｐ＜Ｐｍａｘ」が成立するときには（Ｓ１２０：ＹＥＳ）、分散板６０が正常であると判断されて、本処理は一旦終了される。   When the back pressure P is a value between the upper limit back pressure value Pmax and the lower limit back pressure value Pmin, that is, when “Pmin <P <Pmax” is satisfied (S120: YES), the dispersion plate 60 Is determined to be normal, the process is temporarily terminated.

一方、背圧Ｐが、上限背圧値Ｐｍａｘと下限背圧値Ｐｍｉｎとの間の値になっていないとき、つまり「Ｐｍｉｎ≧Ｐ」または「Ｐ≧Ｐｍａｘ」が成立するときには（Ｓ１２０：ＮＯ）、分散板６０に異常有りと判定されて（Ｓ１３０）、本処理は一旦終了される。なお、ステップＳ１３０にて、分散板６０に異常有りと判定された場合には、警告灯の点灯等を行うことで車両の運転者に異常の発生が報知される。   On the other hand, when the back pressure P is not between the upper limit back pressure value Pmax and the lower limit back pressure value Pmin, that is, when “Pmin ≧ P” or “P ≧ Pmax” is satisfied (S120: NO). Then, it is determined that there is an abnormality in the dispersion plate 60 (S130), and this process is temporarily terminated. If it is determined in step S130 that there is an abnormality in the dispersion plate 60, the vehicle driver is notified of the occurrence of the abnormality by turning on a warning lamp or the like.

先のステップＳ２１０にて、差圧ΔＰが、上限差圧値ΔＰｍａｘと下限差圧値ΔＰｍｉｎとの間の値になっていないと判定されるとき、つまり「ΔＰｍｉｎ≧ΔＰ」または「ΔＰ≧ΔＰｍａｘ」が成立するときには（Ｓ２１０：ＮＯ）、ステップＳ３１０にて、ＮＯｘ浄化率Ｒが浄化率判定値αよりも小さいか否かが判定される。このステップＳ３１０での処理は、ステップＳ１１０での処理と同一である。そして、ＮＯｘ浄化率Ｒが浄化率判定値α以上であるときには（Ｓ３１０：ＮＯ）、ＮＯｘの浄化が正常に行われていると判断されて、本処理は一旦終了される。   When it is determined in step S210 that the differential pressure ΔP is not between the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin, that is, “ΔPmin ≧ ΔP” or “ΔP ≧ ΔPmax”. Is established (S210: NO), it is determined in step S310 whether or not the NOx purification rate R is smaller than the purification rate determination value α. The process in step S310 is the same as the process in step S110. When the NOx purification rate R is equal to or greater than the purification rate determination value α (S310: NO), it is determined that NOx purification is normally performed, and this process is temporarily terminated.

一方、ＮＯｘ浄化率Ｒが浄化率判定値αよりも小さいときには（Ｓ３１０：ＹＥＳ）、フィルタ３２に異常有りと判定されて（Ｓ３２０）、本処理は一旦終了される。
次に、本実施形態特有の作用を説明する。 On the other hand, when the NOx purification rate R is smaller than the purification rate determination value α (S310: YES), it is determined that there is an abnormality in the filter 32 (S320), and this process is temporarily terminated.
Next, operations unique to the present embodiment will be described.

本実施形態の異常判定処理では、フィルタ３２の差圧ΔＰが上限差圧値ΔＰｍａｘと下限差圧値ΔＰｍｉｎとの間の値でないときは、分散板６０の異常判定を行わないようにしている。ここで、上述したように再生処理が終了した直後の差圧ΔＰは、アッシュの堆積量によって変化する。従って、こうしたアッシュ堆積量による差圧ΔＰの変化を考慮することなく、上限差圧値ΔＰｍａｘ及び下限差圧値ΔＰｍｉｎを設定すると、分散板６０の異常判定を行うか否かの判定精度が悪化するようになる。   In the abnormality determination process of this embodiment, when the differential pressure ΔP of the filter 32 is not a value between the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin, the abnormality determination of the dispersion plate 60 is not performed. Here, as described above, the differential pressure ΔP immediately after completion of the regeneration process varies depending on the amount of ash deposited. Accordingly, if the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin are set without considering such a change in the differential pressure ΔP due to the amount of ash deposition, the determination accuracy for determining whether or not the dispersion plate 60 is abnormally deteriorated. It becomes like this.

そこで、本実施形態の異常判定処理では、上限差圧値ΔＰｍａｘ及び下限差圧値ΔＰｍｉｎをフィルタ３２のアッシュ堆積量に応じて可変設定するようにしている。従って、分散板６０の異常判定を行うか否かの判定精度が高くなる。   Therefore, in the abnormality determination process of the present embodiment, the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin are variably set according to the ash accumulation amount of the filter 32. Therefore, the determination accuracy for determining whether or not the dispersion plate 60 is abnormal is increased.

また、再生処理が終了した直後の差圧ΔＰが上限差圧値ΔＰｍａｘ以上に大きいときには、フィルタ３２を通過する排気の量が少なくなっているため、ＳＣＲ触媒４１に流入する排気の流量が減少し、これによりＳＣＲ触媒４１に供給される単位時間当たりの還元剤の量が不足してＮＯｘ浄化率Ｒが低下するおそれがある。また、再生処理が終了した直後の差圧ΔＰが下限差圧値ΔＰｍｉｎ以下に小さいときには、フィルタ３２を通過する排気の量が多くなっているため、ＳＣＲ触媒４１に流入する排気の流量が増大する。このようにして排気流量が増大すると、還元剤を含んだ排気がＳＣＲ触媒４１を速やかに通過してしまうため、ＳＣＲ触媒４１に貯留される還元剤の量が不足してＮＯｘ浄化率Ｒが低下するおそれがある。つまり、ＮＯｘ浄化率Ｒが所定値よりも低い場合であって、差圧ΔＰが上限差圧値ΔＰｍａｘと下限差圧値ΔＰｍｉｎとの間の値ではないときには、フィルタ３２に異常が生じていると判定することができる。 Further, when the differential pressure ΔP immediately after the regeneration process is greater than or equal to the upper limit differential pressure value ΔPmax, the amount of exhaust gas passing through the filter 32 is small, so the flow rate of exhaust gas flowing into the SCR catalyst 41 decreases. As a result, the amount of reducing agent supplied to the SCR catalyst 41 per unit time may be insufficient, and the NOx purification rate R may decrease. In addition, when the differential pressure ΔP immediately after the regeneration process is smaller than the lower limit differential pressure value ΔPmin, the amount of exhaust passing through the filter 32 is large, so the flow rate of exhaust flowing into the SCR catalyst 41 increases. . When the exhaust gas flow rate increases in this way, the exhaust gas containing the reducing agent quickly passes through the SCR catalyst 41, so that the amount of reducing agent stored in the SCR catalyst 41 is insufficient and the NOx purification rate R decreases. There is a risk. That is, when the NOx purification rate R is lower than the predetermined value and the differential pressure ΔP is not a value between the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin, it is assumed that an abnormality has occurred in the filter 32. Can be determined.

そこで、本実施形態の異常判定処理では、再生処理が終了した直後の差圧ΔＰが上限差圧値ΔＰｍａｘと下限差圧値ΔＰｍｉｎとの間の値ではなく（ステップＳ２１０の否定判定）、かつＮＯｘ浄化率Ｒが浄化率判定値αよりも低いときには（ステップＳ３１０での肯定判定）、ステップＳ３２０にて、フィルタ３２に異常ありと判定される。従って、分散板６０の異常のみならず、フィルタ３２の異常も判定することができる。   Therefore, in the abnormality determination process of the present embodiment, the differential pressure ΔP immediately after the regeneration process ends is not a value between the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin (negative determination in step S210), and NOx When the purification rate R is lower than the purification rate determination value α (affirmative determination in step S310), it is determined in step S320 that the filter 32 is abnormal. Therefore, not only the abnormality of the dispersion plate 60 but also the abnormality of the filter 32 can be determined.

以上説明したように、本実施形態によれば、第２実施形態の効果に加えて、さらに次の効果を得ることができる。
（４）フィルタ３２の差圧ΔＰが上限差圧値ΔＰｍａｘと下限差圧値ΔＰｍｉｎとの間の値でないときは、分散板６０の異常判定を行わないようにしている。そして、上限差圧値ΔＰｍａｘと下限差圧値ΔＰｍｉｎとをフィルタ３２のアッシュ堆積量に応じて可変設定するようにしている。より詳細には、アッシュ堆積量と相関する車両の総走行距離ＴＲが長いほど、上限差圧値ΔＰｍａｘ及び下限差圧値ΔＰｍｉｎは大きくなるように可変設定している。従って、分散板６０の異常判定を行うか否かの判定精度を高めることができるようになる。 As described above, according to the present embodiment, the following effects can be obtained in addition to the effects of the second embodiment.
(4) When the differential pressure ΔP of the filter 32 is not a value between the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin, the abnormality determination of the dispersion plate 60 is not performed. Then, the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin are variably set according to the ash accumulation amount of the filter 32. More specifically, the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin are variably set to increase as the total travel distance TR of the vehicle that correlates with the ash accumulation amount is longer. Accordingly, it is possible to improve the accuracy of determining whether or not to perform abnormality determination of the dispersion plate 60.

（５）再生処理が終了した直後の差圧ΔＰが上限差圧値ΔＰｍａｘと下限差圧値ΔＰｍｉｎとの間の値ではなく、かつＮＯｘ浄化率Ｒが浄化率判定値αよりも低いときには、フィルタ３２に異常ありと判定するようにしている。従って、分散板６０の異常のみならず、フィルタ３２の異常も判定することができるようになる。   (5) When the differential pressure ΔP immediately after the regeneration process is not a value between the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin, and the NOx purification rate R is lower than the purification rate determination value α, the filter 32 is determined to be abnormal. Therefore, not only the abnormality of the dispersion plate 60 but also the abnormality of the filter 32 can be determined.

なお、上記各実施形態は以下のように変更して実施することもできる。
・第２実施形態において、先の図３に示したステップＳ２１０の処理を省略する、つまり差圧ΔＰの比較判定処理を省略してもよい。この場合でも第２実施形態で説明した（２）の効果を得ることができる。 In addition, each said embodiment can also be changed and implemented as follows.
-In 2nd Embodiment, you may abbreviate | omit the process of step S210 previously shown in FIG. 3, ie, the comparison determination process of differential pressure | voltage (DELTA) P. Even in this case, the effect (2) described in the second embodiment can be obtained.

・第３実施形態では、上限差圧値ΔＰｍａｘ及び下限差圧値ΔＰｍｉｎの可変設定に際して、車両の総走行距離ＴＲとアッシュ堆積量との相関を利用するようにした。この他、アッシュは、再生処理での微粒子の燃え残りでもあるため、再生処理の実行回数が多いほどアッシュ堆積量は多くなる。そこで、先の図５に示すように、フィルタ３２の再生処理の実行回数が多いほど、上限差圧値ΔＰｍａｘ及び下限差圧値ΔＰｍｉｎは大きくなるように可変設定するようにしてもよい。なお、この変形例は、フィルタ３２の再生処理の実行回数を制御装置８０に記憶しておくことにより、容易に実施できる。   In the third embodiment, when the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin are variably set, the correlation between the total travel distance TR of the vehicle and the ash accumulation amount is used. In addition, since ash is also the unburned fine particles in the regeneration process, the amount of ash deposition increases as the number of regeneration processes is increased. Therefore, as shown in FIG. 5, the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin may be variably set so as to increase the number of times the filter 32 is regenerated. This modification can be easily implemented by storing the number of times the regeneration process of the filter 32 is executed in the control device 80.

また、上述したように、アッシュは、再生処理での微粒子の燃え残りでもあるため、フィルタ３２に捕集された微粒子の積算量、換言すれば再生処理によって処理された微粒子の総量が多いほどアッシュ堆積量は多くなる。そこで、先の図５に示すように、ＰＭ堆積量ＰＭｓｍの積算値が多いほど、上限差圧値ΔＰｍａｘ及び下限差圧値ΔＰｍｉｎは大きくなるように可変設定するようにしてもよい。   Further, as described above, ash is also the unburned residue of fine particles in the regeneration process. Therefore, the greater the total amount of fine particles collected by the filter 32, in other words, the greater the total amount of fine particles processed by the regeneration process, the more the ash. The amount of deposition increases. Therefore, as shown in FIG. 5, the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin may be variably set as the integrated value of the PM accumulation amount PMsm increases.

・第３実施形態では、再生処理が終了した直後の差圧ΔＰが上限差圧値ΔＰｍａｘと下限差圧値ΔＰｍｉｎとの間の値ではなく、かつＮＯｘ浄化率Ｒが浄化率判定値αよりも低いときには、フィルタ３２に異常ありと判定するようにしたが、これらの各処理を省略してもよい。この場合でも、第３実施形態で説明した（４）の効果を得ることができる。 In the third embodiment, the differential pressure ΔP immediately after completion of the regeneration process is not a value between the upper limit differential pressure value ΔPmax and the lower limit differential pressure value ΔPmin, and the NOx purification rate R is greater than the purification rate determination value α. When it is low, it is determined that the filter 32 is abnormal, but each of these processes may be omitted. Even in this case, the effect (4) described in the third embodiment can be obtained.

・還元剤として尿素水を使用するようにしたが、この他の液状の還元剤を使用するようにしてもよい。
・ＮＯｘ浄化触媒として、選択還元型ＮＯｘ触媒とは異なる触媒を用いてもよい。 Although urea water is used as the reducing agent, other liquid reducing agents may be used.
As the NOx purification catalyst, a catalyst different from the selective reduction type NOx catalyst may be used.

１…エンジン、２…シリンダヘッド、３…吸気通路、４ａ〜４ｄ…燃料噴射弁、５…燃料添加弁、６ａ〜６ｄ…排気ポート、７…インテークマニホールド、８…エキゾーストマニホール、９…コモンレール、１０…サプライポンプ、１１…ターボチャージャ、１３…ＥＧＲ通路、１４…ＥＧＲクーラ、１５…ＥＧＲ弁、１６…吸気絞り弁、１７…アクチュエータ、１８…インタークーラ、１９…エアフロメータ、２０…絞り弁開度センサ、２１…機関回転速度センサ、２２…アクセルセンサ、２３…外気温センサ、２４…車速センサ、２５…イグニッションスイッチ、２６…排気通路、２７…燃料供給管、３０…第１浄化部材、３１…酸化触媒、３２…フィルタ、４０…第２浄化部材、４１…選択還元型ＮＯｘ触媒（ＳＣＲ触媒）、５０…第３浄化部材、５１…アンモニア酸化触媒、６０…分散板、８０…制御装置、１００…第１排気温度センサ、１１０…差圧センサ、１２０…第２排気温度センサ、１３０…第１ＮＯｘセンサ、１４０…第２ＮＯｘセンサ、１５０…圧力センサ、２００…尿素水供給機構（還元剤供給機構）、２１０…タンク、２２０…ポンプ、２３０…尿素添加弁、２４０…供給通路。   DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Cylinder head, 3 ... Intake passage, 4a-4d ... Fuel injection valve, 5 ... Fuel addition valve, 6a-6d ... Exhaust port, 7 ... Intake manifold, 8 ... Exhaust manifold, 9 ... Common rail, DESCRIPTION OF SYMBOLS 10 ... Supply pump, 11 ... Turbocharger, 13 ... EGR passage, 14 ... EGR cooler, 15 ... EGR valve, 16 ... Intake throttle valve, 17 ... Actuator, 18 ... Intercooler, 19 ... Air flow meter, 20 ... Throttle valve opening Degree sensor, 21 ... Engine rotation speed sensor, 22 ... Accelerator sensor, 23 ... Outside air temperature sensor, 24 ... Vehicle speed sensor, 25 ... Ignition switch, 26 ... Exhaust passage, 27 ... Fuel supply pipe, 30 ... First purification member, 31 ... oxidation catalyst, 32 ... filter, 40 ... second purification member, 41 ... selective reduction type NOx catalyst (SCR catalyst), 50 ... first Purifying member 51 ... Ammonia oxidation catalyst 60 ... Dispersion plate 80 ... Control device 100 ... First exhaust temperature sensor 110 ... Differential pressure sensor 120 ... Second exhaust temperature sensor 130 ... First NOx sensor 140 ... First 2 ... NOx sensor, 150 ... pressure sensor, 200 ... urea water supply mechanism (reducing agent supply mechanism), 210 ... tank, 220 ... pump, 230 ... urea addition valve, 240 ... supply passage.

Claims (4)

還元剤の供給によりＮＯｘを浄化するＮＯｘ浄化触媒と、還元剤を排気通路内に供給する還元剤供給機構と、排気通路内に設けられて前記ＮＯｘ浄化触媒よりも上流で還元剤を分散させる分散板とを備える内燃機関の排気浄化装置において、
前記分散板よりも上流の排気圧を検出する圧力センサと、この圧力センサの上流に設けられ、排気中の微粒子を捕集するとともに再生処理が行われるフィルタと、このフィルタの上流及び下流の排気圧の圧力差を検出する差圧センサとを備え、
前記ＮＯｘ浄化触媒でのＮＯｘ浄化率が所定値よりも低く、かつ前記再生処理が終了した直後の前記排気圧が予め定められた上限圧力値と下限圧力値との間の値でないときには、前記分散板に異常ありと判定する異常判定を行い、
前記再生処理が終了した直後の前記圧力差が予め定められた上限差圧値と下限差圧値との間の値でないときには、前記異常判定を禁止し、
前記内燃機関が搭載された車両の総走行距離が長いほど、前記上限差圧値及び前記下限差圧値は大きくなるように可変設定される
ことを特徴とする内燃機関の排気浄化装置。 A NOx purification catalyst that purifies NOx by supplying a reducing agent, a reducing agent supply mechanism that supplies the reducing agent into the exhaust passage, and a dispersion that is provided in the exhaust passage and disperses the reducing agent upstream of the NOx purification catalyst. In an exhaust gas purification apparatus for an internal combustion engine comprising a plate,
A pressure sensor that detects the exhaust pressure upstream of the dispersion plate, a filter that is provided upstream of the pressure sensor, collects particulates in the exhaust gas, and performs a regeneration process, and exhausts upstream and downstream of the filter. A differential pressure sensor for detecting a pressure difference between atmospheric pressures,
When the NOx purification rate at the NOx purification catalyst is lower than a predetermined value and the exhaust pressure immediately after the regeneration process is finished is not a value between a predetermined upper limit pressure value and a lower limit pressure value, the dispersion An abnormality determination is made to determine that there is an abnormality in the board,
When the pressure difference immediately after the regeneration process is not a value between a predetermined upper limit differential pressure value and a lower limit differential pressure value, the abnormality determination is prohibited,
The exhaust gas purification apparatus for an internal combustion engine, wherein the upper limit differential pressure value and the lower limit differential pressure value are variably set so as to increase the total travel distance of the vehicle on which the internal combustion engine is mounted. 還元剤の供給によりＮＯｘを浄化するＮＯｘ浄化触媒と、還元剤を排気通路内に供給する還元剤供給機構と、排気通路内に設けられて前記ＮＯｘ浄化触媒よりも上流で還元剤を分散させる分散板とを備える内燃機関の排気浄化装置において、
前記分散板よりも上流の排気圧を検出する圧力センサと、
この圧力センサの上流に設けられ、排気中の微粒子を捕集するとともに再生処理が行われるフィルタと、
このフィルタの上流及び下流の排気圧の圧力差を検出する差圧センサとを備え、
前記ＮＯｘ浄化触媒でのＮＯｘ浄化率が所定値よりも低く、かつ前記再生処理が終了した直後の前記排気圧が予め定められた上限圧力値と下限圧力値との間の値でないときには、前記分散板に異常ありと判定する異常判定を行い、
前記再生処理が終了した直後の前記圧力差が予め定められた上限差圧値と下限差圧値との間の値でないときには、前記異常判定を禁止し、
前記再生処理の実行回数が多いほど、前記上限差圧値及び前記下限差圧値は大きくなるように可変設定される
ことを特徴とする内燃機関の排気浄化装置。 A NOx purification catalyst that purifies NOx by supplying a reducing agent, a reducing agent supply mechanism that supplies the reducing agent into the exhaust passage, and a dispersion that is provided in the exhaust passage and disperses the reducing agent upstream of the NOx purification catalyst. In an exhaust gas purification apparatus for an internal combustion engine comprising a plate,
A pressure sensor for detecting an exhaust pressure upstream of the dispersion plate;
A filter that is provided upstream of the pressure sensor and that collects particulates in the exhaust and performs a regeneration process;
A differential pressure sensor for detecting the pressure difference between the exhaust pressure upstream and downstream of the filter,
When the NOx purification rate at the NOx purification catalyst is lower than a predetermined value and the exhaust pressure immediately after the regeneration process is finished is not a value between a predetermined upper limit pressure value and a lower limit pressure value, the dispersion An abnormality determination is made to determine that there is an abnormality in the board,
When the pressure difference immediately after the regeneration process is not a value between a predetermined upper limit differential pressure value and a lower limit differential pressure value, the abnormality determination is prohibited,
The exhaust gas purification apparatus for an internal combustion engine, wherein the upper limit differential pressure value and the lower limit differential pressure value are variably set so as to increase the number of times the regeneration process is executed. 還元剤の供給によりＮＯｘを浄化するＮＯｘ浄化触媒と、還元剤を排気通路内に供給する還元剤供給機構と、排気通路内に設けられて前記ＮＯｘ浄化触媒よりも上流で還元剤を分散させる分散板とを備える内燃機関の排気浄化装置において、
前記分散板よりも上流の排気圧を検出する圧力センサと、
この圧力センサの上流に設けられ、排気中の微粒子を捕集するとともに再生処理が行われるフィルタと、
このフィルタの上流及び下流の排気圧の圧力差を検出する差圧センサとを備え、
前記ＮＯｘ浄化触媒でのＮＯｘ浄化率が所定値よりも低く、かつ前記再生処理が終了した直後の前記排気圧が予め定められた上限圧力値と下限圧力値との間の値でないときには、前記分散板に異常ありと判定する異常判定を行い、
前記再生処理が終了した直後の前記圧力差が予め定められた上限差圧値と下限差圧値との間の値でないときには、前記異常判定を禁止し、
前記フィルタに捕集された微粒子の総積算量が多いほど、前記上限差圧値及び前記下限差圧値は大きくなるように可変設定される
ことを特徴とする内燃機関の排気浄化装置。 A NOx purification catalyst that purifies NOx by supplying a reducing agent, a reducing agent supply mechanism that supplies the reducing agent into the exhaust passage, and a dispersion that is provided in the exhaust passage and disperses the reducing agent upstream of the NOx purification catalyst. In an exhaust gas purification apparatus for an internal combustion engine comprising a plate,
A pressure sensor for detecting an exhaust pressure upstream of the dispersion plate;
A filter that is provided upstream of the pressure sensor and that collects particulates in the exhaust and performs a regeneration process;
A differential pressure sensor for detecting the pressure difference between the exhaust pressure upstream and downstream of the filter,
When the NOx purification rate at the NOx purification catalyst is lower than a predetermined value and the exhaust pressure immediately after the regeneration process is finished is not a value between a predetermined upper limit pressure value and a lower limit pressure value, the dispersion An abnormality determination is made to determine that there is an abnormality in the board,
When the pressure difference immediately after the regeneration process is not a value between a predetermined upper limit differential pressure value and a lower limit differential pressure value, the abnormality determination is prohibited,
The exhaust gas purification apparatus for an internal combustion engine, wherein the upper limit differential pressure value and the lower limit differential pressure value are variably set so as to increase as the total integrated amount of particulates collected by the filter increases. 前記再生処理が終了した直後の前記圧力差が前記上限差圧値と前記下限差圧値との間の値ではなく、かつ前記ＮＯｘ浄化率が前記所定値よりも低いときには、前記フィルタに異常ありと判定する
請求項１〜３のいずれか１項に記載の内燃機関の排気浄化装置。 When the pressure difference immediately after the regeneration process is not a value between the upper limit differential pressure value and the lower limit differential pressure value and the NOx purification rate is lower than the predetermined value, the filter is abnormal. The exhaust emission control device for an internal combustion engine according to any one of claims 1 to 3.
JP2011243698A 2011-11-07 2011-11-07 Exhaust gas purification device for internal combustion engine Expired - Fee Related JP5573817B2 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP2011243698A JP5573817B2 (en) 2011-11-07 2011-11-07 Exhaust gas purification device for internal combustion engine
DE102012219767.2A DE102012219767B4 (en) 2011-11-07 2012-10-29 EXHAUST CONTROL DEVICE FOR AN INTERNAL COMBUSTION ENGINE

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2011243698A JP5573817B2 (en) 2011-11-07 2011-11-07 Exhaust gas purification device for internal combustion engine

Publications (2)

Publication Number Publication Date
JP2013100729A JP2013100729A (en) 2013-05-23
JP5573817B2 true JP5573817B2 (en) 2014-08-20

Family

ID=48129111

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2011243698A Expired - Fee Related JP5573817B2 (en) 2011-11-07 2011-11-07 Exhaust gas purification device for internal combustion engine

Country Status (2)

Country Link
JP (1) JP5573817B2 (en)
DE (1) DE102012219767B4 (en)

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0711936A (en) * 1993-06-29 1995-01-13 Toyota Autom Loom Works Ltd Exhaust gas purification device
DE19741199C2 (en) * 1997-09-18 2000-10-26 Siemens Ag Static mixer
US7017338B2 (en) * 2003-11-03 2006-03-28 Ford Global Technologies, Llc Diesel particulate filter pressure monitor
JP2006274906A (en) * 2005-03-29 2006-10-12 Mitsubishi Fuso Truck & Bus Corp Exhaust emission control device
JP2007255365A (en) * 2006-03-24 2007-10-04 Nissan Diesel Motor Co Ltd Exhaust emission control device of engine
JP4863111B2 (en) * 2006-08-31 2012-01-25 株式会社デンソー Exhaust purification device
JP2008157200A (en) * 2006-12-26 2008-07-10 Mitsubishi Fuso Truck & Bus Corp Abnormality detection device for exhaust emission control device
JP4877123B2 (en) * 2007-07-23 2012-02-15 マツダ株式会社 Engine exhaust purification system
JP2010150979A (en) * 2008-12-24 2010-07-08 Ud Trucks Corp Exhaust emission control device for engine
JP2010151110A (en) * 2008-12-26 2010-07-08 Toyota Motor Corp Catalyst deterioration determination device for internal combustion engine
JP2011220233A (en) * 2010-04-09 2011-11-04 Mazda Motor Corp Failure determination method for particulate filter and its device

Also Published As

Publication number Publication date
JP2013100729A (en) 2013-05-23
DE102012219767A1 (en) 2013-05-08
DE102012219767B4 (en) 2016-05-04

Similar Documents

Publication Publication Date Title
JP5900608B2 (en) Liquid level detector
JP3979437B1 (en) Exhaust gas purification system control method and exhaust gas purification system
JP2013113267A (en) Exhaust emission purifying apparatus of internal combustion engine
JP6229488B2 (en) Exhaust gas purification device for in-vehicle internal combustion engine
US9067160B2 (en) Exhaust gas purification system
JP4211611B2 (en) Exhaust gas purification device for internal combustion engine
JP5834773B2 (en) Exhaust gas purification device for internal combustion engine
JP2012031798A (en) Exhaust gas purification system
JP5118460B2 (en) Exhaust purification device
JP5787083B2 (en) Exhaust gas purification device for internal combustion engine
JP5716687B2 (en) Exhaust gas purification device for internal combustion engine
JP2013144938A (en) Exhaust emission control system of internal combustion engine
JP5834831B2 (en) Exhaust gas purification device for internal combustion engine
JP5699922B2 (en) Exhaust gas purification device for internal combustion engine
JP2014224510A (en) Exhaust emission control device of internal combustion engine
EP3055524B1 (en) Exhaust gas control apparatus for an internal combustion engine and corresponding control method
JP5573817B2 (en) Exhaust gas purification device for internal combustion engine
JP2014005741A (en) Exhaust cleaning device of internal combustion engine
EP3071806B1 (en) Exhaust gas control apparatus and exhaust gas control method for internal combustion engine
JP5287940B2 (en) Exhaust gas purification device for internal combustion engine
JP6453702B2 (en) Abnormality diagnosis device for exhaust purification mechanism
JP6274151B2 (en) Urea water abnormality determination device
JP2021008863A (en) Exhaust emission control device of internal combustion engine

Legal Events

Date Code Title Description
A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20130906

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20130910

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20131031

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20140507

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20140514

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20140603

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20140616

R151 Written notification of patent or utility model registration

Ref document number: 5573817

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R151

LAPS Cancellation because of no payment of annual fees