JP2020183714A - Exhaust emission control device - Google Patents

Exhaust emission control device Download PDF

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JP2020183714A
JP2020183714A JP2019087433A JP2019087433A JP2020183714A JP 2020183714 A JP2020183714 A JP 2020183714A JP 2019087433 A JP2019087433 A JP 2019087433A JP 2019087433 A JP2019087433 A JP 2019087433A JP 2020183714 A JP2020183714 A JP 2020183714A
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reducing agent
urea water
exhaust gas
amount
agent solution
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JP7163862B2 (en
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飯田　達也
Tatsuya Iida
達也 飯田
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Toyota Industries Corp
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • 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
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • 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
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Combustion & Propulsion (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Biomedical Technology (AREA)
  • Environmental & Geological Engineering (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Exhaust Gas After Treatment (AREA)
  • Exhaust Gas Treatment By Means Of Catalyst (AREA)

Abstract

To provide an exhaust emission control device which can determine the replenishment of a reductant aqueous solution even if small-amount replenishment which is not detected by a residual amount detection device of water or a low-density reductant aqueous solution is continued.SOLUTION: An exhaust emission control device comprises: a reductant addition valve arranged at an upstream side rather than a selective reduction catalyst for selectively purifying NOx in an exhaust gas, and adding a reductant solution supplied from a reductant tank to the exhaust gas at each prescribed time; an integration amount determination device for determining whether or not an integration addition amount of the reductant solution added by the reductant addition valve reaches a prescribed integration determination value or larger; a residual amount determination device for determining whether or not a residual amount of the reductant solution in the reductant tank is equal to a prescribed level or higher which can be detected by a residual amount detection device; and a first replenishment determination device for determining that the reductant solution has been replenished to the reductant tank when it is determined that the integration addition amount reaches the prescribed integration determination value of larger, and also it is determined that the residual amount of the reductant solution in the reductant tank is equal to a prescribed level or higher.SELECTED DRAWING: Figure 1

Description

本発明は、内燃機関から排出される窒素酸化物（ＮＯｘ）を浄化する排気ガス浄化装置に関する。 The present invention relates to an exhaust gas purifying device that purifies nitrogen oxides (NOx) discharged from an internal combustion engine.

内燃機関から排出される窒素酸化物（ＮＯｘ）を浄化する排気ガス浄化装置に関して種々提案されている。例えば、下記特許文献１に記載された排気浄化システムでは、尿素水タンク内には、尿素水タンク内に貯留されている尿素水残量（水位）を検出する尿素水位センサが設けられている。そして、ＥＣＵは、エンジン停止時における尿素水タンク内の停止時水位と、次回のエンジン始動時における尿素水タンク内の始動時水位とを検出する。 Various proposals have been made for an exhaust gas purifying device that purifies nitrogen oxides (NOx) emitted from an internal combustion engine. For example, in the exhaust gas purification system described in Patent Document 1 below, a urea water level sensor for detecting the remaining amount of urea water (water level) stored in the urea water tank is provided in the urea water tank. Then, the ECU detects the stop water level in the urea water tank when the engine is stopped and the start water level in the urea water tank when the engine is started next time.

続いて、ＥＣＵは、始動時水位が停止時水位から上昇側判定値αよりも大きく上昇しているか否かを判定する。そして、始動時水位が停止時水位から上昇側判定値αよりも大きく上昇していると判定した場合には、ＥＣＵは、尿素水タンク内に尿素水が補給されたと判定して、選択還元触媒の下流側に配置されたＮＯｘセンサによって検出されるＮＯｘ浄化率が適正値であるか否かを判定する。ＮＯｘ浄化率が適正でないと判定した場合には、ＥＣＵは、適正な尿素水が補給されていないと判定して、警告を行うように構成されている。 Subsequently, the ECU determines whether or not the starting water level has risen more than the rising side determination value α from the stopped water level. Then, when it is determined that the water level at the start is higher than the water level at the stop than the rising side determination value α, the ECU determines that the urea water has been replenished in the urea water tank, and the selective reduction catalyst. It is determined whether or not the NOx purification rate detected by the NOx sensor arranged on the downstream side of the is an appropriate value. When it is determined that the NOx purification rate is not appropriate, the ECU is configured to determine that the appropriate urea water is not replenished and give a warning.

特開２０１０−１８０７５３号公報JP-A-2010-180753

しかしながら、前記特許文献１に記載された排気浄化システムでは、ＥＣＵは、始動時水位が停止時水位から上昇側判定値αよりも大きく上昇した場合に、尿素水タンク内に補給された尿素水の品質検査を行う。このため、規定濃度（例えば、３２．５％）よりも低い濃度の尿素水又は水の尿素水位センサによって検出されない少量補給が続く場合には、ＥＣＵは、尿素水の補給判定ができないため、尿素水の濃度が低下しているにもかかわらず、ＮＯｘ浄化率を検出しない。その結果、ＥＣＵは、尿素水タンク内の尿素水の品質異常を長期間に渡って検出できない虞がある。 However, in the exhaust purification system described in Patent Document 1, when the water level at the start rises more than the rising side determination value α from the water level at the stop, the ECU replenishes the urea water in the urea water tank. Perform a quality inspection. Therefore, if a small amount of urea water or water whose concentration is lower than the specified concentration (for example, 32.5%) is continuously replenished without being detected by the urea water level sensor, the ECU cannot determine the replenishment of urea water. NOx purification rate is not detected even though the water concentration is decreasing. As a result, the ECU may not be able to detect the quality abnormality of the urea water in the urea water tank for a long period of time.

そこで、本発明は、このような点に鑑みて創案されたものであり、低濃度の還元剤水溶液又は水の残量検出装置で検出できない少量補給が続いても、還元剤水溶液の補給判定を行うことができる排気ガス浄化装置を提供することを目的とする。 Therefore, the present invention was devised in view of these points, and even if a small amount of replenishment that cannot be detected by the low-concentration reducing agent aqueous solution or the remaining amount of water detection device continues, the replenishment determination of the reducing agent aqueous solution can be determined. It is an object of the present invention to provide an exhaust gas purification device which can be performed.

上記課題を解決するため、本発明の第１の発明は、所定濃度の還元剤溶液を貯留する還元剤タンクと、前記還元剤タンク内の前記還元剤溶液の残量を検出する残量検出装置と、内燃機関の排気ガス通路に配置されて前記還元剤溶液により排気ガス中のＮＯｘを選択的に浄化する選択還元触媒と、前記排気ガス通路における前記選択還元触媒よりも上流側に配置されて、前記還元剤タンクから供給された還元剤溶液を所定時間毎に排気ガスに添加する還元剤添加弁と、前記還元剤添加弁によって添加された還元剤溶液の添加量を積算する添加量積算装置と、前記添加量積算装置が積算した積算添加量が所定の積算判定値以上に達したか否かを判定する積算量判定装置と、前記還元剤タンク内の前記還元剤溶液の残量が、前記残量検出装置によって検出可能となる所定レベル以上であるか否かを判定する残量判定装置と、前記積算量判定装置によって前記積算添加量が所定の積算判定値以上に達したと判定されると共に、前記残量判定装置によって前記還元剤溶液の残量が前記所定レベル以上であると判定された場合に、前記還元剤タンクに前記還元剤溶液の補給が行われたと判定する第１補給判定装置と、を備えた、排気ガス浄化装置である。 In order to solve the above problems, the first invention of the present invention is a reducing agent tank for storing a reducing agent solution having a predetermined concentration, and a remaining amount detecting device for detecting the remaining amount of the reducing agent solution in the reducing agent tank. A selective reducing catalyst that is arranged in the exhaust gas passage of the internal combustion engine and selectively purifies NOx in the exhaust gas by the reducing agent solution, and a selective reducing catalyst that is arranged upstream of the selective reducing catalyst in the exhaust gas passage. , A reducing agent addition valve that adds the reducing agent solution supplied from the reducing agent tank to the exhaust gas at predetermined time intervals, and an addition amount integrating device that integrates the addition amount of the reducing agent solution added by the reducing agent addition valve. The integrated amount determination device for determining whether or not the integrated addition amount integrated by the addition amount integrating device has reached a predetermined integration determination value or more, and the remaining amount of the reducing agent solution in the reducing agent tank are It is determined by the remaining amount determination device that determines whether or not the level is equal to or higher than the predetermined level that can be detected by the remaining amount detecting device, and that the integrated addition amount has reached the predetermined integrated determination value or more by the integrated amount determination device. At the same time, when the remaining amount of the reducing agent solution is determined by the remaining amount determination device to be equal to or higher than the predetermined level, it is determined that the reducing agent solution has been replenished to the reducing agent tank. It is an exhaust gas purification device provided with a determination device.

次に、本発明の第２の発明は、上記第１の発明に係る排気ガス浄化装置において、前記積算判定値は、前記還元剤タンクの満タンから前記残量検出装置によって検出可能となる前記所定レベルまでの前記還元剤溶液の減少量以上に設定されている、排気ガス浄化装置である。 Next, in the second invention of the present invention, in the exhaust gas purification device according to the first invention, the integrated determination value can be detected by the remaining amount detecting device from the full tank of the reducing agent tank. An exhaust gas purification device set to a reduction amount of the reducing agent solution up to a predetermined level or more.

次に、本発明の第３の発明は、上記第１の発明又は第２の発明に係る排気ガス浄化装置において、前記残量検出装置によって前記還元剤タンク内への前記還元剤溶液の所定量以上の補給を検出する補給検出装置と、前記補給検出装置によって前記還元剤溶液の所定量以上の補給が検出された場合に、前記還元剤タンクに前記還元剤溶液の補給が行われたと判定する第２補給判定装置と、を備えた、排気ガス浄化装置である。 Next, in the third invention of the present invention, in the exhaust gas purifying device according to the first invention or the second invention, a predetermined amount of the reducing agent solution is put into the reducing agent tank by the remaining amount detecting device. When the replenishment detection device for detecting the above replenishment and the replenishment detection device detect replenishment of the reducing agent solution in a predetermined amount or more, it is determined that the reducing agent solution has been replenished in the reducing agent tank. An exhaust gas purification device including a second replenishment determination device.

次に、本発明の第４の発明は、上記第３の発明に係る排気ガス浄化装置において、前記選択還元触媒の触媒温度を検出する触媒温度検出装置と、前記触媒温度検出装置によって検出した前記触媒温度に基づいて目標ＮＯｘ浄化率を取得する目標浄化率取得装置と、前記選択還元触媒によって浄化された実ＮＯｘ浄化率を取得する実浄化率取得装置と、前記内燃機関の運転状態を検出する運転状態検出装置と、前記還元剤タンクに前記還元剤溶液の補給が行われたと判定された場合には、前記運転状態が所定運転状態になった際に、前記目標ＮＯｘ浄化率と前記実ＮＯｘ浄化率とに基づいて、前記還元剤添加弁によって添加する還元剤溶液の添加量を設定すると共に、設定された前記添加量を学習値として記憶する添加量調整装置と、を備えた、排気ガス浄化装置である。 Next, the fourth invention of the present invention is the exhaust gas purification device according to the third invention, wherein the catalyst temperature detecting device for detecting the catalyst temperature of the selective reducing catalyst and the catalyst temperature detecting device for detecting the catalyst temperature are detected. Detects the target purification rate acquisition device that acquires the target NOx purification rate based on the catalyst temperature, the actual purification rate acquisition device that acquires the actual NOx purification rate purified by the selective reducing catalyst, and the operating state of the internal combustion engine. When it is determined that the operating state detecting device and the reducing agent tank have been replenished with the reducing agent solution, the target NOx purification rate and the actual NOx are obtained when the operating state reaches a predetermined operating state. Exhaust gas provided with an addition amount adjusting device for setting the addition amount of the reducing agent solution added by the reducing agent addition valve based on the purification rate and storing the set addition amount as a learning value. It is a purification device.

次に、本発明の第５の発明は、上記第４の発明に係る排気ガス浄化装置において、前記添加量調整装置は、前記第２補給判定装置を介して前記還元剤タンクに前記還元剤溶液の補給が行われたと判定された場合には、前記学習値を所定の初期添加量に再設定して記憶する、排気ガス浄化装置である。 Next, according to a fifth aspect of the present invention, in the exhaust gas purifying device according to the fourth invention, the addition amount adjusting device puts the reducing agent solution in the reducing agent tank via the second replenishment determination device. This is an exhaust gas purification device that resets and stores the learned value to a predetermined initial addition amount when it is determined that the replenishment has been performed.

次に、本発明の第６の発明は、上記第４の発明又は第５の発明に係る排気ガス浄化装置において、前記学習値が異常判定閾値以上になったか否かを判定する学習値判定装置と、前記学習値判定装置によって前記学習値が異常判定閾値以上になったと判定された場合には、前記還元剤タンク内の前記還元剤溶液の品質は、異常であると判定する品質判定装置と、を備えた、排気ガス浄化装置である。 Next, the sixth invention of the present invention is the learning value determination device for determining whether or not the learning value is equal to or higher than the abnormality determination threshold in the exhaust gas purification device according to the fourth invention or the fifth invention. When it is determined by the learning value determination device that the learning value is equal to or higher than the abnormality determination threshold value, the quality of the reducing agent solution in the reducing agent tank is determined to be abnormal. It is an exhaust gas purification device equipped with.

第１の発明によれば、還元剤添加弁によって添加された還元剤溶液の積算添加量が所定の積算判定値以上に達したと判定されると共に、還元剤タンク内の還元剤溶液の残量が、残量検出装置によって検出可能となる所定レベル以上であると判定された場合に、還元剤タンクに還元剤溶液の補給が行われたと判定される。 According to the first invention, it is determined that the cumulative addition amount of the reducing agent solution added by the reducing agent addition valve has reached a predetermined cumulative determination value or more, and the remaining amount of the reducing agent solution in the reducing agent tank. However, when it is determined that the level is equal to or higher than the predetermined level that can be detected by the remaining amount detecting device, it is determined that the reducing agent solution has been replenished to the reducing agent tank.

これにより、規定濃度よりも低い濃度の還元剤溶液又は水の少量補給が続いて、還元剤タンク内の還元剤溶液の減少を残量検出装置で検出できない所定レベル以上の残量であっても、還元剤溶液の積算添加量が所定の積算判定値以上に達する適切なタイミングで、還元剤タンクに還元剤溶液の補給が行われたと判定することができる。その結果、適切なタイミングでＮＯｘ浄化率を測定して、還元剤タンク内に補給された還元剤溶液の品質検査を行う頻度を多くすることができる。 As a result, even if a small amount of the reducing agent solution or water having a concentration lower than the specified concentration is continuously replenished and the decrease of the reducing agent solution in the reducing agent tank cannot be detected by the remaining amount detecting device, the remaining amount is equal to or higher than the predetermined level. , It can be determined that the reducing agent solution has been replenished to the reducing agent tank at an appropriate timing when the cumulative addition amount of the reducing agent solution reaches a predetermined integrated determination value or more. As a result, the NOx purification rate can be measured at an appropriate timing, and the frequency of quality inspection of the reducing agent solution replenished in the reducing agent tank can be increased.

第２の発明によれば、積算判定値は、還元剤タンクの満タンから残量検出装置によって検出可能となる所定レベルまでの還元剤溶液の減少量以上に設定されている。これにより、残量検出装置によって減少を検出できない規定濃度よりも低い濃度の還元剤溶液又は水の少量補給が続いて、還元剤タンク内の還元剤溶液の残量が所定レベル以上であっても、還元剤タンク内の還元剤溶液の品質検査を行う必要がある還元剤溶液の補給量に達したか否かを適切に判定することができる。 According to the second invention, the integrated determination value is set to be equal to or greater than the amount of decrease of the reducing agent solution from the full tank of the reducing agent tank to a predetermined level that can be detected by the remaining amount detecting device. As a result, even if the remaining amount of the reducing agent solution in the reducing agent tank is equal to or higher than the predetermined level, a small amount of the reducing agent solution or water having a concentration lower than the specified concentration whose decrease cannot be detected by the remaining amount detecting device is continuously replenished. , It is possible to appropriately determine whether or not the replenishment amount of the reducing agent solution needs to be inspected for the quality of the reducing agent solution in the reducing agent tank.

第３の発明によれば、補給検出装置によって還元剤溶液の所定量以上の補給が検出された場合に、還元剤タンクに還元剤溶液の補給が行われたと判定される。これにより、１回で通常量の還元剤溶液の補給が行われた場合と、還元剤溶液の少量補給が続いて還元剤添加弁による積算添加量が積算判定値以上になると共に、還元剤溶液の残量が所定レベル以上である場合と、のいずれかにおいて、ＮＯｘ浄化率を測定して、還元剤タンク内に補給された還元剤溶液の品質検査を行うことができる。従って、還元剤タンク内に補給された還元剤溶液の品質検査の頻度を多くして、還元剤タンク内の還元剤溶液の品質向上を図ることが可能となり、ＮＯｘ浄化率の向上を図ることができる。 According to the third invention, when the replenishment detection device detects the replenishment of the reducing agent solution in a predetermined amount or more, it is determined that the reducing agent solution has been replenished to the reducing agent tank. As a result, when the normal amount of the reducing agent solution is replenished at one time, and when a small amount of the reducing agent solution is continuously replenished, the integrated addition amount by the reducing agent addition valve becomes equal to or more than the integrated judgment value, and the reducing agent solution is replenished. The NOx purification rate can be measured and the quality of the reducing agent solution replenished in the reducing agent tank can be inspected in either the case where the remaining amount of the reducing agent is equal to or higher than a predetermined level. Therefore, it is possible to increase the frequency of quality inspection of the reducing agent solution replenished in the reducing agent tank to improve the quality of the reducing agent solution in the reducing agent tank, and to improve the NOx purification rate. it can.

第４の発明によれば、添加量調整装置は、還元剤タンクに還元剤溶液の補給が行われたと判定された場合には、運転状態が所定運転状態になった際に、目標ＮＯｘ浄化率と実ＮＯｘ浄化率とに基づいて、還元剤添加弁によって添加する還元剤溶液の添加量を設定し、学習値として記憶する。これにより、添加量調整装置は、規定濃度よりも低い濃度の還元剤溶液又は水の残量検出装置によって検出できない少量補給が続いて、還元剤タンク内の還元剤溶液の残量が所定レベル以上であっても、還元剤タンクに還元剤溶液が補給されたと判定された際に、還元剤添加弁の添加量を再設定することができる。従って、ＮＯｘ浄化率に対応する還元剤添加弁の適切な添加量を再設定することが可能となり、引いてはＮＯｘ浄化を適正に行うことができる。 According to the fourth invention, when it is determined that the reducing agent solution has been replenished to the reducing agent tank, the addition amount adjusting device has a target NOx purification rate when the operating state becomes a predetermined operating state. And the actual NOx purification rate, the amount of the reducing agent solution added by the reducing agent addition valve is set and stored as a learning value. As a result, the addition amount adjusting device continues to supply a small amount of the reducing agent solution having a concentration lower than the specified concentration or a small amount of water that cannot be detected by the remaining amount detecting device of water, and the remaining amount of the reducing agent solution in the reducing agent tank exceeds a predetermined level. Even so, the amount of the reducing agent addition valve added can be reset when it is determined that the reducing agent solution has been replenished in the reducing agent tank. Therefore, it is possible to reset an appropriate addition amount of the reducing agent addition valve corresponding to the NOx purification rate, and by extension, NOx purification can be performed appropriately.

第５の発明によれば、１回で通常量の還元剤溶液の補給が行われた際には、添加量調整装置は、設定された学習値を所定の初期添加量に再設定して記憶する。これにより、添加量調整装置は、規定濃度の還元剤溶液を補給されたものとして還元剤添加弁の添加量を設定することができる。従って、還元剤添加弁の適切な添加量を迅速に設定することが可能となり、引いてはＮＯｘ浄化を適正に行うことができる。 According to the fifth invention, when the normal amount of the reducing agent solution is replenished at one time, the addition amount adjusting device resets the set learning value to a predetermined initial addition amount and stores it. To do. As a result, the addition amount adjusting device can set the addition amount of the reducing agent addition valve as if the reducing agent solution having a specified concentration was replenished. Therefore, it is possible to quickly set an appropriate addition amount of the reducing agent addition valve, and by extension, NOx purification can be appropriately performed.

第６の発明によれば、学習値判定装置によって学習値が異常判定閾値以上になったと判定された場合には、還元剤タンク内の還元剤溶液の品質は、異常であると判定される。これにより、還元剤タンク内の還元剤溶液の品質異常を確実に検出することが可能となり、品質検査の精度の向上を図ることが可能となる。 According to the sixth invention, when the learning value is determined by the learning value determination device to be equal to or higher than the abnormality determination threshold value, the quality of the reducing agent solution in the reducing agent tank is determined to be abnormal. As a result, it is possible to reliably detect quality abnormalities of the reducing agent solution in the reducing agent tank, and it is possible to improve the accuracy of the quality inspection.

本実施形態に係る排気ガス浄化装置を適用した内燃機関の構成の一例を説明する図である。It is a figure explaining an example of the structure of the internal combustion engine to which the exhaust gas purification apparatus which concerns on this embodiment is applied. 制御装置が実行する尿素水の品質異常の有無を判定する尿素水品質判定処理のメインフローチャートである。It is a main flowchart of the urea water quality determination process which determines whether or not there is a quality abnormality of urea water executed by a control device. 図２の尿素水補給判定処理のサブ処理を示すサブフローチャートである。It is a sub-flow chart which shows the sub-process of the urea water supply determination process of FIG. 図２の尿素水添加量の積算処理のサブ処理を示すサブフローチャートである。It is a sub-flow chart which shows the sub-processing of the integration processing of the urea water addition amount of FIG. 図２の積算添加量判定処理のサブ処理を示すサブフローチャートである。It is a sub-flow chart which shows the sub-process of the integrated addition amount determination process of FIG. 図２の尿素水添加量学習処理のサブ処理を示すサブフローチャートである。It is a sub-flow chart which shows the sub-process of the urea water addition amount learning process of FIG. 図２の品質異常警告処理のサブ処理を示すサブフローチャートである。It is a sub-flow chart which shows the sub-processing of the quality abnormality warning processing of FIG. 尿素水タンクの通常補給の一例を説明する図である。It is a figure explaining an example of normal replenishment of a urea water tank. 尿素水の積算添加量の変化の一例を説明する図である。It is a figure explaining an example of the change of the cumulative addition amount of urea water. 目標ＮＯｘ浄化率と触媒温度との関係を示す図である。It is a figure which shows the relationship between the target NOx purification rate and the catalyst temperature. 尿素水添加量の学習を説明する図である。It is a figure explaining the learning of the addition amount of urea water.

以下、本発明に係る排気ガス浄化装置を具体化した一実施形態に基づき図面を参照しつつ詳細に説明する。図１は、本発明に係る排気ガス浄化装置を適用した内燃機関１０の構成の一例を示している。内燃機関１０は、ディーゼルエンジンである。ここで、内燃機関１０は、高効率で耐久性にも優れているが、粒子状物質（ＰＭ）、窒素酸化物（ＮＯｘ）、一酸化炭素（ＣＯ）、炭化水素（ＨＣ）等の有害物質を、排気ガスと一緒に排出してしまうものである。 Hereinafter, the exhaust gas purification device according to the present invention will be described in detail with reference to the drawings based on the embodiment. FIG. 1 shows an example of the configuration of an internal combustion engine 10 to which the exhaust gas purification device according to the present invention is applied. The internal combustion engine 10 is a diesel engine. Here, the internal combustion engine 10 has high efficiency and excellent durability, but is a harmful substance such as particulate matter (PM), nitrogen oxide (NOx), carbon monoxide (CO), and hydrocarbon (HC). Is discharged together with the exhaust gas.

図１に示すように、内燃機関１０の排気通路（排気ガス通路）１２には、排気ガス浄化装置４０が設けられている。排気ガス浄化装置４０は、上流側排気ガス浄化装置４１と、上流側排気ガス浄化装置４１の下流側に配置される下流側排気ガス浄化装置４５とから構成されている。上流側排気ガス浄化装置４１の内部には、上流側から、第１酸化触媒（ＤＯＣ：Diesel Oxidation Catalyst）４２、粒子状物質除去フィルタ（ＤＰＦ：Diesel Particulate Filter）４３が設けられている。 As shown in FIG. 1, an exhaust gas purifying device 40 is provided in the exhaust passage (exhaust gas passage) 12 of the internal combustion engine 10. The exhaust gas purification device 40 is composed of an upstream exhaust gas purification device 41 and a downstream exhaust gas purification device 45 arranged on the downstream side of the upstream exhaust gas purification device 41. Inside the upstream exhaust gas purification device 41, a first oxidation catalyst (DOC: Diesel Oxidation Catalyst) 42 and a particulate matter removal filter (DPF: Diesel Particulate Filter) 43 are provided from the upstream side.

第１酸化触媒４２は、セラミック製の円柱状等に形成されたセル状筒体からなり、その軸方向には多数の貫通孔が形成され、内面に白金（Ｐｔ）等の貴金属がコーティングされている。そして、第１酸化触媒４２は、所定の温度下で多数の貫通孔に排気ガスを通すことにより、排気ガスに含まれる一酸化炭素（ＣＯ）、炭化水素（ＨＣ）等を酸化して除去する。 The first oxidation catalyst 42 is made of a cell-shaped cylinder formed of a ceramic columnar shape or the like, and a large number of through holes are formed in the axial direction thereof, and the inner surface is coated with a precious metal such as platinum (Pt). There is. Then, the first oxidation catalyst 42 oxidizes and removes carbon monoxide (CO), hydrocarbons (HC) and the like contained in the exhaust gas by passing the exhaust gas through a large number of through holes at a predetermined temperature. ..

粒子状物質除去フィルタ（以下、「ＤＰＦ」という。）４３は、セラミックス材料等からなる多孔質な部材によって円柱状等に形成され、軸方向に多数の小孔が設けられたハニカム構造のセル状筒体をなし、各小孔は、隣同士で交互に異なる端部が目封じ部材によって閉塞されている。そして、ＤＰＦ４３は、上流側から各小孔に流入する排気ガスを多孔質材料に通すことで粒子状物質（ＰＭ）を捕集し、排気ガスのみを隣の小孔を通じて下流側へと流出させる。 The particulate matter removal filter (hereinafter referred to as “DPF”) 43 is formed in a columnar shape or the like by a porous member made of a ceramic material or the like, and has a honeycomb structure cell shape in which a large number of small holes are provided in the axial direction. It forms a tubular body, and each small hole is closed with a sealing member at an end that is alternately different from each other. Then, the DPF 43 collects particulate matter (PM) by passing the exhaust gas flowing into each small hole from the upstream side through the porous material, and causes only the exhaust gas to flow out to the downstream side through the adjacent small hole. ..

第１酸化触媒４２の上流側（上流側排気ガス浄化装置４１の上流側）には、燃料添加弁２８と、排気温度検出装置３６Ａ（例えば、排気温度センサ）と、が設けられている。燃料添加弁２８は、微粒子が堆積したＤＰＦ４３を再生する際（粒子状物質を燃焼焼却する際）に、第１酸化触媒４２内で排気ガスと反応させて排気ガスの温度を上昇させるための燃料を噴射する。また、第１酸化触媒４２の下流側、且つ、ＤＰＦ４３の上流側には、排気温度検出装置３６Ｂ（例えば、排気温度センサ）が設けられている。 A fuel addition valve 28 and an exhaust temperature detection device 36A (for example, an exhaust temperature sensor) are provided on the upstream side of the first oxidation catalyst 42 (upstream side of the upstream exhaust gas purification device 41). The fuel addition valve 28 is a fuel for raising the temperature of the exhaust gas by reacting with the exhaust gas in the first oxidation catalyst 42 when regenerating the DPF 43 in which fine particles are deposited (when burning and incinerating the particulate matter). Is injected. Further, an exhaust temperature detection device 36B (for example, an exhaust temperature sensor) is provided on the downstream side of the first oxidation catalyst 42 and on the upstream side of the DPF 43.

ＤＰＦ４３の下流側には、排気温度検出装置３６Ｃ（例えば、排気温度センサ）が設けられている。また、上流側排気ガス浄化装置４１内における、第１酸化触媒４２の下流側、且つ、ＤＰＦ４３の上流側の排気圧力（排気管内圧力に相当）と、ＤＰＦ４３の下流側の排気管内圧力と、の差圧（圧力差）を検出する差圧センサ３５が設けられている。 An exhaust temperature detection device 36C (for example, an exhaust temperature sensor) is provided on the downstream side of the DPF 43. Further, in the upstream exhaust gas purification device 41, the exhaust pressure on the downstream side of the first oxidation catalyst 42 and on the upstream side of the DPF 43 (corresponding to the pressure in the exhaust pipe) and the pressure in the exhaust pipe on the downstream side of the DPF 43. A differential pressure sensor 35 for detecting the differential pressure (pressure difference) is provided.

また、上流側排気ガス浄化装置４１の下流側に配置される下流側排気ガス浄化装置４５は、上流側から、尿素水添加弁（還元剤添加弁）６１、選択還元触媒（ＳＣＲ：Selective Catalytic Reduction）４６、第２酸化触媒４７が設けられている。選択還元触媒（以下、「ＳＣＲ」という。）４６は、ＤＰＦ４３の下流側に排気管１２Ａを介して連結されている。尿素水添加弁６１は、排気管１２ＡのＤＰＦ４３の下流側、且つ、ＳＣＲ４６の上流側に配置されて、所定時間（例えば、２００ミリ秒〜４００ミリ秒である。）毎に、ＳＣＲ４６に向けて排気ガス中に尿素水（還元剤溶液）を添加（噴霧）する。また、排気管１２Ａには、尿素水添加弁６１の上流側に、ＮＯｘセンサ３７Ａが設けられている。 Further, the downstream exhaust gas purification device 45 arranged on the downstream side of the upstream exhaust gas purification device 41 has a urea water addition valve (reducing agent addition valve) 61 and a selective reduction catalyst (SCR: Selective Catalytic Reduction) from the upstream side. ) 46, the second oxidation catalyst 47 is provided. The selective reduction catalyst (hereinafter referred to as “SCR”) 46 is connected to the downstream side of the DPF 43 via an exhaust pipe 12A. The urea water addition valve 61 is arranged on the downstream side of the DPF43 of the exhaust pipe 12A and on the upstream side of the SCR46, and is directed toward the SCR46 at predetermined time intervals (for example, 200 ms to 400 ms). Urea water (reducing agent solution) is added (sprayed) into the exhaust gas. Further, the exhaust pipe 12A is provided with a NOx sensor 37A on the upstream side of the urea water addition valve 61.

第２酸化触媒４７は、ＳＣＲ４６の下流側に、排気管１２Ｂを介して連結されている。排気管１２Ｂには、ＳＣＲ４６の下流側に、排気温度検出装置（触媒温度検出装置）３６Ｄ（例えば、排気温度センサ）が設けられている。また、排気管１２Ｂには、排気温度検出装置３６Ｄの下流側に、ＮＯｘセンサ３７Ｂが設けられている。各ＮＯｘセンサ３７Ａ、３７Ｂは、排気ガス中のＮＯｘ濃度に応じた検出信号を出力する。 The second oxidation catalyst 47 is connected to the downstream side of the SCR 46 via an exhaust pipe 12B. The exhaust pipe 12B is provided with an exhaust temperature detection device (catalyst temperature detection device) 36D (for example, an exhaust temperature sensor) on the downstream side of the SCR46. Further, the exhaust pipe 12B is provided with a NOx sensor 37B on the downstream side of the exhaust temperature detection device 36D. Each of the NOx sensors 37A and 37B outputs a detection signal according to the NOx concentration in the exhaust gas.

尿素水添加弁６１は、供給管６２、尿素水ポンプ６３を介して尿素水タンク（還元剤タンク）６５に連結される。尿素水ポンプ６３は、制御装置（ＥＣＵ）５０からの駆動信号により回転駆動される電動ポンプであり、正逆いずれの方向にも回転が可能となっている。尿素水ポンプ６３の正回転により尿素水タンク６５内の尿素水（還元剤溶液）６７の吸い上げが行われ、尿素水６７が供給管６２を介して尿素水添加弁６１に供給される。また、尿素水ポンプ６３の逆回転により供給管６２内の尿素水６７が吸い戻され、尿素水タンク６５内に流入される。尚、供給管６２には、供給管６２内の尿素水６７の圧力を検出する水圧センサを設けてもよい。 The urea water addition valve 61 is connected to the urea water tank (reducing agent tank) 65 via the supply pipe 62 and the urea water pump 63. The urea water pump 63 is an electric pump that is rotationally driven by a drive signal from the control device (ECU) 50, and can rotate in either the forward or reverse direction. The forward rotation of the urea water pump 63 causes the urea water (reducing agent solution) 67 in the urea water tank 65 to be sucked up, and the urea water 67 is supplied to the urea water addition valve 61 via the supply pipe 62. Further, the urea water 67 in the supply pipe 62 is sucked back by the reverse rotation of the urea water pump 63, and flows into the urea water tank 65. The supply pipe 62 may be provided with a water pressure sensor that detects the pressure of the urea water 67 in the supply pipe 62.

尿素水タンク６５内には、尿素水タンク６５内に貯留されている尿素水６７の残量（水位）を検出するレベルゲージ（残量検出装置）６８が設けられている。レベルゲージ（残量検出装置）６８は、図８に示すように、尿素水タンク６５内の尿素水６７が満タン（例えば、１３リットルである。）から所定量（例えば、６リットルである。）以上減少した残量に応じた信号（例えば、レベル６〜レベル１に相当する信号である。）を制御装置（ＥＣＵ）５０に出力する。 A level gauge (remaining amount detecting device) 68 for detecting the remaining amount (water level) of the urea water 67 stored in the urea water tank 65 is provided in the urea water tank 65. As shown in FIG. 8, the level gauge (remaining amount detecting device) 68 has a predetermined amount (for example, 6 liters) of urea water 67 in the urea water tank 65 from a full tank (for example, 13 liters). ) A signal corresponding to the remaining amount reduced by the above (for example, a signal corresponding to level 6 to level 1) is output to the control device (ECU) 50.

ＳＣＲ４６は、尿素水添加弁６１により添加された尿素水（還元剤溶液）を用いて窒素酸化物（ＮＯｘ）を無害化する触媒である。具体的には、尿素水添加弁６１から添加（噴射）された尿素水は、排気ガスの排気熱によって加水分解され、その際、下記式（１）に示す反応によりアンモニア（ＮＨ3）が生成される。
（ＮＨ2）2ＣＯ＋Ｈ2Ｏ→２ＮＨ3＋ＣＯ2 ・・・（１） SCR46 is a catalyst that detoxifies nitrogen oxides (NOx) by using urea water (reducing agent solution) added by the urea water addition valve 61. Specifically, the urea water added (injected) from the urea water addition valve 61 is hydrolyzed by the exhaust heat of the exhaust gas, and at that time, ammonia (NH 3 ) is generated by the reaction represented by the following formula (1). Will be done.
(NH 2 ) 2 CO + H 2 O → 2 NH 3 + CO 2 ... (1)

そして、ＳＣＲ４６を排気ガスが通過する際に、ＳＣＲ４６に吸着したアンモニアによって排気ガス中の窒素酸化物（ＮＯｘ）が選択的に還元浄化される。その際、下記式（２）〜式（４）に示すような還元反応が行われることによって、ＮＯｘが還元浄化される。
４ＮＯ＋４ＮＨ3＋Ｏ2→４Ｎ2＋６Ｈ2Ｏ ・・・（２）
６ＮＯ2＋８ＮＨ3→７Ｎ2＋１２Ｈ2Ｏ ・・・（３）
ＮＯ＋ＮＯ2＋２ＮＨ3→２Ｎ2＋３Ｈ2Ｏ ・・・（４） Then, when the exhaust gas passes through the SCR46, the nitrogen oxides (NOx) in the exhaust gas are selectively reduced and purified by the ammonia adsorbed on the SCR46. At that time, NOx is reduced and purified by performing a reduction reaction as shown in the following formulas (2) to (4).
4NO + 4NH 3 + O 2 → 4N 2 + 6H 2 O ・ ・ ・ (2)
6NO 2 + 8NH 3 → 7N 2 + 12H 2 O ・ ・ ・ (3)
NO + NO 2 + 2NH 3 → 2N 2 + 3H 2 O ・ ・ ・ (4)

上記式（２）〜式（４）に示すアンモニアによるＮＯｘの還元浄化が行われる際、アンモニアがＮＯｘと反応しきれずに余剰となると、その余剰アンモニアがＳＣＲ４６の下流側の排気管１２Ｂを介して第２酸化触媒４７に流入する。かかる場合に、第２酸化触媒４７は、流入した余剰アンモニアを酸化して除去する。 When NOx is reduced and purified by ammonia represented by the above formulas (2) to (4), if the ammonia cannot completely react with NOx and becomes surplus, the surplus ammonia passes through the exhaust pipe 12B on the downstream side of the SCR46. It flows into the second oxidation catalyst 47. In such a case, the second oxidation catalyst 47 oxidizes and removes the excess ammonia that has flowed in.

燃料添加弁２８、尿素水添加弁６１、尿素水ポンプ６３は、制御装置（ＥＣＵ：Electronic Control Unit）５０からの制御信号にて駆動される。制御装置５０は、ＣＰＵ、ＲＡＭ、ＲＯＭ、タイマ、ＥＥＰＲＯＭ等を備えた公知のものである。ＣＰＵは、ＲＯＭに記憶された各種プログラムやマップに基づいて、種々の演算処理を実行する。また、ＲＡＭは、ＣＰＵでの演算結果や各検出装置から入力されたデータ等を一時的に記憶し、ＥＥＰＲＯＭは、例えば、内燃機関１０の停止時にその保存すべきデータ等を記憶する。また、ＥＥＰＲＯＭには、尿素水添加弁６１によって添加（噴射）した尿素水を積算した積算添加量を記憶する積算添加量記憶部５０１と、後述のように、学習した尿素水添加弁６１から添加される尿素水添加量の学習値を記憶する学習値記憶部５０２と、が設けられている。 The fuel addition valve 28, the urea water addition valve 61, and the urea water pump 63 are driven by a control signal from the control device (ECU: Electronic Control Unit) 50. The control device 50 is a known one including a CPU, RAM, ROM, timer, EEPROM and the like. The CPU executes various arithmetic processes based on various programs and maps stored in the ROM. Further, the RAM temporarily stores the calculation result of the CPU, the data input from each detection device, and the like, and the EEPROM stores, for example, the data to be saved when the internal combustion engine 10 is stopped. Further, the EEPROM is added to the EEPROM from the integrated addition amount storage unit 501 that stores the integrated addition amount of the urea water added (injected) by the urea water addition valve 61, and from the learned urea water addition valve 61 as described later. A learning value storage unit 502 for storing the learning value of the urea water addition amount to be added is provided.

また、排気温度検出装置３６Ａは、第１酸化触媒４２の上流側の排気管内の排気ガスの温度に応じた検出信号を制御装置５０に出力する。また、排気温度検出装置３６Ｂは、第１酸化触媒４２の下流側、且つ、ＤＰＦ４３の上流側を流れる排気ガスの温度に応じた検出信号を制御装置５０に出力する。また、排気温度検出装置３６Ｃは、ＤＰＦ４３の下流側、且つ、ＳＣＲ４６の上流側の排気ガスの温度に応じた検出信号を制御装置５０に出力する。また、排気温度検出装置３６Ｄは、ＳＣＲ４６の下流側、且つ、第２酸化触媒４７の上流側の排気ガスの温度に応じた検出信号を制御装置５０に出力する。 Further, the exhaust temperature detection device 36A outputs a detection signal according to the temperature of the exhaust gas in the exhaust pipe on the upstream side of the first oxidation catalyst 42 to the control device 50. Further, the exhaust temperature detection device 36B outputs a detection signal according to the temperature of the exhaust gas flowing on the downstream side of the first oxidation catalyst 42 and the upstream side of the DPF 43 to the control device 50. Further, the exhaust temperature detection device 36C outputs a detection signal according to the temperature of the exhaust gas on the downstream side of the DPF 43 and the upstream side of the SCR 46 to the control device 50. Further, the exhaust temperature detection device 36D outputs a detection signal according to the temperature of the exhaust gas on the downstream side of the SCR 46 and the upstream side of the second oxidation catalyst 47 to the control device 50.

差圧センサ３５は、第１酸化触媒４２の下流側、且つ、ＤＰＦ４３の上流側の排気圧力（排気管内圧力に相当）と、ＤＰＦ４３の下流側の排気管内圧力と、の差圧に応じた検出信号を制御装置５０に出力する。ＮＯｘセンサ３７Ａは、尿素水添加弁６１よりも上流側の排気ガスのＮＯｘ濃度に応じた検出信号を制御装置５０に出力する。ＮＯｘセンサ３７Ｂは、ＳＣＲ４６の下流側、且つ、第２酸化触媒４７の上流側の排気ガスのＮＯｘ濃度に応じた検出信号を制御装置５０に出力する。レベルゲージ（残量検出装置）６８は、尿素水タンク６５内に貯留された尿素水６７の所定量以上減少した残量に応じた検出信号（例えば、レベル６〜レベル１）を制御装置５０に出力する。 The differential pressure sensor 35 detects the exhaust pressure on the downstream side of the first oxidation catalyst 42 and on the upstream side of the DPF 43 (corresponding to the pressure inside the exhaust pipe) and the pressure inside the exhaust pipe on the downstream side of the DPF 43 according to the differential pressure. The signal is output to the control device 50. The NOx sensor 37A outputs a detection signal according to the NOx concentration of the exhaust gas on the upstream side of the urea water addition valve 61 to the control device 50. The NOx sensor 37B outputs a detection signal according to the NOx concentration of the exhaust gas on the downstream side of the SCR 46 and the upstream side of the second oxidation catalyst 47 to the control device 50. The level gauge (remaining amount detecting device) 68 sends a detection signal (for example, level 6 to level 1) according to the remaining amount of urea water 67 stored in the urea water tank 65 to the control device 50. Output.

制御装置５０には、吸気通路１１に設けられた吸入空気流量検出装置３１（例えば、エアフローメーター）の検出信号、アクセル開度検出装置３３の検出信号、回転検出装置３４の検出信号、のそれぞれが入力されている。また、制御装置５０には、上述した各排気温度検出装置３６Ａ、３６Ｂ、３６Ｃ、３６Ｄの検出信号、差圧センサ３５の検出信号、各ＮＯｘセンサ３７Ａ、３７Ｂの検出信号、レベルゲージ６８の検出信号が入力されている。 The control device 50 includes a detection signal of an intake air flow rate detection device 31 (for example, an air flow meter) provided in the intake passage 11, a detection signal of the accelerator opening degree detection device 33, and a detection signal of the rotation detection device 34. It has been entered. Further, the control device 50 includes the detection signals of the exhaust temperature detection devices 36A, 36B, 36C and 36D described above, the detection signals of the differential pressure sensor 35, the detection signals of the NOx sensors 37A and 37B, and the detection signals of the level gauge 68. Has been entered.

そして、制御装置５０は、これらの入力された検出信号に基づいて内燃機関１０の運転状態を検出することができる。また、制御装置５０は、検出した内燃機関１０の運転状態や、アクセル開度検出装置３３からの検出信号に基づいた運転者からの要求に応じて、各インジェクタ１４Ａ〜１４Ｄから内燃機関１０のシリンダ内に噴射する燃料量や、燃料添加弁２８から噴射する燃料量を制御する制御信号を出力する。 Then, the control device 50 can detect the operating state of the internal combustion engine 10 based on these input detection signals. Further, the control device 50 receives the detected operating state of the internal combustion engine 10 and the cylinder of the internal combustion engine 10 from the injectors 14A to 14D in response to a request from the driver based on the detection signal from the accelerator opening detection device 33. A control signal for controlling the amount of fuel injected into the engine and the amount of fuel injected from the fuel addition valve 28 is output.

そして、制御装置５０（流量関連量検出装置に相当する。）は、各インジェクタ１４Ａ〜１４Ｄから噴射した毎秒当たりの燃料消費量（ｇ／ｓ）を所定時間（例えば、約１０ｍｓｅｃ〜１００ｍｓｅｃ）毎に算出して、ＲＡＭに時系列的に記憶する。また、制御装置５０（差圧検出装置に相当する。）は、差圧センサ３５から入力された検出信号から差圧（圧力差）を所定時間（例えば、約１０ｍｓｅｃ〜１００ｍｓｅｃ）毎に算出して、ＲＡＭに時系列的に記憶する。 Then, the control device 50 (corresponding to the flow rate related amount detection device) determines the fuel consumption (g / s) per second injected from each injector 14A to 14D every predetermined time (for example, about 10 msec to 100 msec). Calculate and store in RAM in chronological order. Further, the control device 50 (corresponding to the differential pressure detecting device) calculates the differential pressure (pressure difference) from the detection signal input from the differential pressure sensor 35 every predetermined time (for example, about 10 msec to 100 msec). , Stored in RAM in chronological order.

燃料添加弁２８から排気ガス中に噴射された燃料は、第１酸化触媒４２によって排気ガス中に残った酸素との酸化反応が生じて燃焼し、その発熱により排気ガス温度が上昇する。この高温になった排気ガスによりＤＰＦ４３の床温が上昇して、所定温度以上（例えば、５９０℃以上）になると、ＤＰＦ４３内に堆積した粒子状物質（ＰＭ）が燃焼焼却される。このような状態を所定の時間、維持することによってＤＰＦ４３内に堆積した粒子状物質（ＰＭ）を燃焼させて除去し、排気ガス中の粒子状物質（ＰＭ）を捕集するというＤＰＦ４３の捕集機能を回復（再生）させることができる。 The fuel injected into the exhaust gas from the fuel addition valve 28 is burned by an oxidation reaction with oxygen remaining in the exhaust gas by the first oxidation catalyst 42, and the exhaust gas temperature rises due to the heat generation. When the floor temperature of the DPF43 rises due to the high temperature exhaust gas and reaches a predetermined temperature or higher (for example, 590 ° C. or higher), the particulate matter (PM) deposited in the DPF43 is burned and incinerated. By maintaining such a state for a predetermined time, the particulate matter (PM) deposited in the DPF43 is burned and removed, and the particulate matter (PM) in the exhaust gas is collected. The function can be restored (regenerated).

吸入空気流量検出装置３１（例えば、吸気流量センサ）は、内燃機関１０の吸気通路１１に設けられて内燃機関１０が吸入した空気の流量に応じた検出信号を制御装置５０に出力する。アクセル開度検出装置３３（例えば、アクセル開度センサ）は、運転者が操作するアクセルの開度（すなわち、運転者の要求負荷）に応じた検出信号を制御装置５０に出力する。回転検出装置３４（例えば、回転センサ）は、例えば、内燃機関１０のクランクシャフトの回転数（すなわち、エンジン回転数）に応じた検出信号を制御装置５０に出力する。 The intake air flow rate detection device 31 (for example, an intake air flow rate sensor) is provided in the intake passage 11 of the internal combustion engine 10 and outputs a detection signal according to the flow rate of the air sucked by the internal combustion engine 10 to the control device 50. The accelerator opening degree detecting device 33 (for example, the accelerator opening degree sensor) outputs a detection signal to the control device 50 according to the opening degree of the accelerator operated by the driver (that is, the load required by the driver). The rotation detection device 34 (for example, a rotation sensor) outputs a detection signal according to the rotation speed of the crankshaft of the internal combustion engine 10 (that is, the engine rotation speed) to the control device 50, for example.

また、図１に示す例では、制御装置５０は、後述のように、尿素水タンク６５内に貯留された尿素水６７の品質異常を検出した際に点灯する尿素水警告ランプ１５の点灯／消灯が可能である。尿素水警告ランプ１５は、例えば、車両のインスツルメントパネル内に設けられている。 Further, in the example shown in FIG. 1, as will be described later, the control device 50 turns on / off the urea water warning lamp 15 that lights up when a quality abnormality of the urea water 67 stored in the urea water tank 65 is detected. Is possible. The urea water warning lamp 15 is provided, for example, in the instrument panel of the vehicle.

次に、上記のように構成された内燃機関１０において、制御装置５０による尿素水タンク６５内に残留する尿素水６７の品質異常の有無を判定する尿素水品質判定処理の一例について図２乃至図１１に基づいて説明する。尚、制御装置５０は、内燃機関１０の運転中に、所定時間間隔（例えば、数１０ｍｓｅｃ〜数１００ｍｓｅｃ間隔）にて、図２のフローチャートに示される処理手順を繰り返し実行する。 Next, FIGS. 2 to 2 show an example of the urea water quality determination process for determining the presence or absence of quality abnormality of the urea water 67 remaining in the urea water tank 65 by the control device 50 in the internal combustion engine 10 configured as described above. It will be described based on 11. The control device 50 repeatedly executes the processing procedure shown in the flowchart of FIG. 2 at predetermined time intervals (for example, at intervals of several tens of msec to several 100 msec) during the operation of the internal combustion engine 10.

図２に示すように、先ず、ステップＳ１１において、制御装置５０は、尿素水タンク６５内に通常の尿素水の補給が行われた否かを判定する「尿素水補給判定処理」のサブ処理を実行した後、ステップＳ１２に進む。ここで、「尿素水補給判定処理」のサブ処理について図３及び図８に基づいて説明する。図３に示すように、先ず、ステップＳ１１１において、制御装置５０は、レベルゲージ６８によって尿素水タンク６５内の尿素水６７の現在の残量を計測してＲＡＭに記憶する。 As shown in FIG. 2, first, in step S11, the control device 50 performs a sub-process of "urea water replenishment determination process" for determining whether or not normal urea water is replenished in the urea water tank 65. After the execution, the process proceeds to step S12. Here, the sub-processing of the "urea water replenishment determination process" will be described with reference to FIGS. 3 and 8. As shown in FIG. 3, first, in step S111, the control device 50 measures the current remaining amount of the urea water 67 in the urea water tank 65 by the level gauge 68 and stores it in the RAM.

続いて、ステップＳ１１２において、制御装置５０は、前回の内燃機関１０の停止時に、レベルゲージ６８によって計測した尿素水６７の停止時の残量をＥＥＰＲＯＭから読み出し、尿素水６７の現在の残量が、前回の停止時の残量から所定量（例えば、レベルゲージ６８で検出可能なレベル１からレベル２まで等の１レベル分の増加量で、約１リットル）以上増加しているか否かを判定する。 Subsequently, in step S112, the control device 50 reads the remaining amount of the urea water 67 measured by the level gauge 68 at the time of stopping from the EEPROM when the internal combustion engine 10 was stopped last time, and the current remaining amount of the urea water 67 is calculated. , Judges whether or not the amount has increased by a predetermined amount (for example, about 1 liter, which is an increase amount of one level from level 1 to level 2 that can be detected by the level gauge 68) from the remaining amount at the time of the previous stop. To do.

つまり、制御装置５０は、尿素水タンク６５内の尿素水６７の補給をレベルゲージ６８によって検出したか否かを判定する。尚、制御装置５０は、内燃機関１０の停止時に、尿素水ポンプ６３を所定時間（例えば、約５秒間）逆回転して供給管６２内の尿素水を尿素水タンク６５内に吸い戻した後、レベルゲージ６８によって尿素水タンク６５内の尿素水６７の残量を計測して、停止時の残量としてＥＥＰＲＯＭに記憶する。 That is, the control device 50 determines whether or not the replenishment of the urea water 67 in the urea water tank 65 is detected by the level gauge 68. When the internal organ engine 10 is stopped, the control device 50 reversely rotates the urea water pump 63 for a predetermined time (for example, about 5 seconds) to suck the urea water in the supply pipe 62 back into the urea water tank 65. , The remaining amount of urea water 67 in the urea water tank 65 is measured by the level gauge 68, and stored in the EEPROM as the remaining amount at the time of stopping.

そして、尿素水タンク６５内の尿素水６７の現在の残量が、前回の停止時の残量から所定量（例えば、約１リットル）以上増加していないと判定した場合、つまり、尿素水６７の補給をレベルゲージ６８によって検出していないと判定した場合には（Ｓ１１２：ＮＯ）、制御装置５０は、当該サブ処理を終了して、メインフローチャートに戻り、ステップＳ１２に進む。 Then, when it is determined that the current remaining amount of the urea water 67 in the urea water tank 65 has not increased by a predetermined amount (for example, about 1 liter) or more from the remaining amount at the time of the previous stop, that is, the urea water 67 If it is determined that the replenishment of the above is not detected by the level gauge 68 (S112: NO), the control device 50 ends the sub-processing, returns to the main flowchart, and proceeds to step S12.

一方、尿素水タンク６５内の尿素水６７の現在の残量が、前回の停止時の残量から所定量（例えば、約１リットル）以上増加していると判定した場合、つまり、尿素水６７の補給をレベルゲージ６８によって検出したと判定した場合には（Ｓ１１２：ＹＥＳ）、制御装置５０は、ステップＳ１１３に進む。ステップＳ１１３において、制御装置５０は、ＲＡＭから第１補給フラグを読み出して、「ＯＮ」に設定した後、再度ＲＡＭに記憶した後、当該サブ処理を終了して、メインフローチャートに戻り、ステップＳ１２に進む。尚、第１補給フラグは、制御装置５０の起動時に、「ＯＦＦ」に設定されてＲＡＭに記憶される。 On the other hand, when it is determined that the current remaining amount of the urea water 67 in the urea water tank 65 has increased by a predetermined amount (for example, about 1 liter) or more from the remaining amount at the time of the previous stop, that is, the urea water 67 If it is determined that the replenishment of the above is detected by the level gauge 68 (S112: YES), the control device 50 proceeds to step S113. In step S113, the control device 50 reads the first supply flag from the RAM, sets it to “ON”, stores it in the RAM again, ends the sub-processing, returns to the main flowchart, and proceeds to step S12. move on. The first replenishment flag is set to "OFF" and stored in the RAM when the control device 50 is started.

ここで、尿素水タンク６５に尿素水６７が補給された一例について図８に基づいて説明する。図８に示すように、時間Ｔ１又は時間Ｔ２のときに、内燃機関１０の前回の停止時に測定した尿素水タンク６５内の尿素水６７の残量が、レベルゲージ６８のレベル１であって、レベルゲージ６８によって測定した尿素水６７の今回の残量が、レベル６以上に増加している、つまり、満タンであった場合には、制御装置５０は、尿素水６７の補給があったと判定する（Ｓ１１２：ＹＥＳ）。そして、制御装置５０は、ＲＡＭから第１補給フラグを読み出して、「ＯＮ」に設定した後、再度ＲＡＭに記憶した後、当該サブ処理を終了して、メインフローチャートに戻り、ステップＳ１２に進む。 Here, an example in which the urea water tank 65 is replenished with the urea water 67 will be described with reference to FIG. As shown in FIG. 8, at time T1 or time T2, the remaining amount of urea water 67 in the urea water tank 65 measured at the time of the previous stop of the internal combustion engine 10 is level 1 of the level gauge 68. When the remaining amount of urea water 67 measured by the level gauge 68 this time has increased to level 6 or higher, that is, when the tank is full, the control device 50 determines that the urea water 67 has been replenished. (S112: YES). Then, the control device 50 reads the first replenishment flag from the RAM, sets it to "ON", stores it in the RAM again, ends the sub-processing, returns to the main flowchart, and proceeds to step S12.

次に、図２に示すように、ステップＳ１２において、制御装置５０は、尿素水添加弁６１によって添加（噴射）する添加量を積算する「尿素水添加量の積算処理」のサブ処理を実行した後、ステップＳ１３に進む。ここで、「尿素水添加量の積算処理」のサブ処理について図４に基づいて説明する。図４に示すように、先ず、ステップＳ１２１において、制御装置５０は、尿素水添加弁６１により尿素水を添加（噴射）したか否かを判定する。 Next, as shown in FIG. 2, in step S12, the control device 50 executed a sub-process of "integration processing of urea water addition amount" for integrating the addition amount to be added (injected) by the urea water addition valve 61. After that, the process proceeds to step S13. Here, the sub-treatment of the "integration treatment of the amount of urea water added" will be described with reference to FIG. As shown in FIG. 4, first, in step S121, the control device 50 determines whether or not urea water has been added (injected) by the urea water addition valve 61.

そして、尿素水添加弁６１により尿素水を添加（噴射）していないと判定した場合には（Ｓ１２１：ＮＯ）、制御装置５０は、当該サブ処理を終了して、メインフローチャートに戻り、ステップＳ１３に進む。一方、尿素水添加弁６１により尿素水を添加（噴射）したと判定した場合には（Ｓ１２１：ＹＥＳ）、制御装置５０は、ステップＳ１２２に進む。 When it is determined that the urea water addition valve 61 has not added (injected) urea water (S121: NO), the control device 50 ends the sub-processing, returns to the main flowchart, and steps S13. Proceed to. On the other hand, when it is determined that the urea water has been added (injected) by the urea water addition valve 61 (S121: YES), the control device 50 proceeds to step S122.

ステップＳ１２２において、制御装置５０は、ＥＥＰＲＯＭの積算添加量記憶部５０１から尿素水の積算添加量を読み出し、今回添加（噴射）した尿素水の添加量を尿素水の積算添加量に加算した後、再度、ＥＥＰＲＯＭの積算添加量記憶部５０１に記憶する。その後、制御装置５０は、当該サブ処理を終了して、メインフローチャートに戻り、ステップＳ１３に進む。尚、ＥＥＰＲＯＭの積算添加量記憶部５０１に記憶される積算添加量は、ＥＥＰＲＯＭの初期化設定時に、「０」が代入されて積算添加量記憶部５０１に記憶される。 In step S122, the control device 50 reads the cumulative addition amount of urea water from the cumulative addition amount storage unit 501 of the EEPROM, adds the addition amount of the urea water added (injected) this time to the cumulative addition amount of urea water, and then. It is stored again in the integrated addition amount storage unit 501 of the EEPROM. After that, the control device 50 ends the sub-processing, returns to the main flowchart, and proceeds to step S13. The cumulative addition amount stored in the cumulative addition amount storage unit 501 of the EEPROM is stored in the cumulative addition amount storage unit 501 by substituting "0" at the time of setting the initialization of the EEPROM.

次に、図２に示すように、ステップＳ１３において、制御装置５０は、ＲＡＭから第１補給フラグを読み出し、「ＯＮ」に設定されているか否かを判定する。そして、第１補給フラグが「ＯＮ」に設定されていると判定した場合には（Ｓ１３：ＹＥＳ）、制御装置５０は、尿素水タンク６５へのレベルゲージ６８によって検出可能な容量の尿素水の補給があったと判定して、ステップＳ１４に進む。 Next, as shown in FIG. 2, in step S13, the control device 50 reads the first supply flag from the RAM and determines whether or not it is set to “ON”. Then, when it is determined that the first replenishment flag is set to "ON" (S13: YES), the control device 50 has a capacity of urea water that can be detected by the level gauge 68 to the urea water tank 65. It is determined that there is replenishment, and the process proceeds to step S14.

ステップＳ１４において、制御装置５０は、ＥＥＰＲＯＭの積算添加量記憶部５０１から尿素水の積算添加量を読み出す。そして、制御装置５０は、積算添加量に「０」を代入してリセットし、再度、積算添加量記憶部５０１に記憶した後、ステップＳ１５に進む。従って、尿素水タンク６５への尿素水の補給がレベルゲージ６８によって検出された際に、第１補給フラグが「ＯＮ」に設定されると共に、積算添加量記憶部５０１に記憶される積算添加量が、リセットされる。これにより、尿素水添加弁６１により添加された尿素水の添加量が、再度、「０」から積算開始される。 In step S14, the control device 50 reads out the cumulative addition amount of urea water from the cumulative addition amount storage unit 501 of the EEPROM. Then, the control device 50 substitutes "0" for the integrated addition amount, resets it, stores it in the integrated addition amount storage unit 501 again, and then proceeds to step S15. Therefore, when the replenishment of urea water to the urea water tank 65 is detected by the level gauge 68, the first replenishment flag is set to "ON" and the integrated addition amount stored in the integrated addition amount storage unit 501. However, it is reset. As a result, the amount of urea water added by the urea water addition valve 61 starts to be integrated again from "0".

続いて、ステップＳ１５において、制御装置５０は、ＥＥＰＲＯＭの学習値記憶部５０２に記憶する尿素水添加弁６１から添加（噴射）される尿素水添加量の学習値を読み出す。そして、制御装置５０は、尿素水添加量の学習値に「初期添加量Ｖ１」（図１１参照）を代入してリセットし、再度、学習値記憶部５０２に記憶した後、後述のステップＳ１８に進む。 Subsequently, in step S15, the control device 50 reads out the learning value of the urea water addition amount added (injected) from the urea water addition valve 61 stored in the learning value storage unit 502 of the EEPROM. Then, the control device 50 substitutes the "initial addition amount V1" (see FIG. 11) for the learning value of the urea water addition amount, resets it, stores it in the learning value storage unit 502 again, and then proceeds to step S18 described later. move on.

尚、「初期添加量Ｖ１」は、規定濃度（例えば、３２．５％）の尿素水６７が尿素水タンク６５内に貯留され、且つ、ＳＣＲ４６が新品である際に、内燃機関の運転状態（エンジン回転数、燃料噴射量等）に応じて、尿素水添加弁６１から添加（噴射）する尿素水のＮＯｘ浄化率が最大となる添加量であって、ＣＡＥ（Computer Aided Engineering）解析、又は、実験により予め取得され、マップや数式によりＲＯＭに予め記憶されている。 The "initial addition amount V1" is the operating state of the internal combustion engine (for example, when the urea water 67 having a specified concentration (for example, 32.5%) is stored in the urea water tank 65 and the SCR46 is new. Depending on the engine speed, fuel injection amount, etc.), the amount of urea water added (injected) from the urea water addition valve 61 maximizes the NOx purification rate, and CAE (Computer Aided Engineering) analysis or CAE (Computer Aided Engineering) analysis or It is acquired in advance by an experiment and stored in ROM in advance by a map or a mathematical formula.

一方、上記ステップＳ１３で第１補給フラグが「ＯＦＦ」に設定されていると判定した場合には（Ｓ１３：ＮＯ）、制御装置５０は、尿素水タンク６５への尿素水の補給はなかったと判定して、ステップＳ１６に進む。ステップＳ１６において、制御装置５０は、「積算添加量判定処理」のサブ処理を実行した後、ステップＳ１７に進む。ここで、「積算添加量判定処理」のサブ処理について図５及び図９に基づいて説明する。図５に示すように、ステップＳ１３１において、制御装置５０は、ＥＥＰＲＯＭの積算添加量記憶部５０１から積算添加量を読み出して、積算添加量が積算判定値Ｚ１以上であるか否かを判定する。 On the other hand, when it is determined in step S13 that the first replenishment flag is set to "OFF" (S13: NO), the control device 50 determines that the urea water tank 65 has not been replenished with urea water. Then, the process proceeds to step S16. In step S16, the control device 50 proceeds to step S17 after executing the sub-process of the "integrated addition amount determination process". Here, the sub-processing of the "integrated addition amount determination processing" will be described with reference to FIGS. 5 and 9. As shown in FIG. 5, in step S131, the control device 50 reads the integrated addition amount from the integrated addition amount storage unit 501 of the EEPROM and determines whether or not the integrated addition amount is equal to or greater than the integrated determination value Z1.

尚、積算判定値Ｚ１は、例えば、図９に示すように、レベルゲージ６８によって計測されるレベル１〜レベル６のうちの、尿素水タンク６５の満タンからレベルゲージ６８で計測可能となるレベル６〜レベル５までの尿素水６７の減少量に設定されている。つまり、積算判定値Ｚ１は、尿素水タンク６５内のレベルゲージ６８によって計測することが可能となるまで減少する尿素水６７の減少量に設定されるのが望ましい。尚、積算判定値Ｚ１は、予めＲＯＭに記憶されている。 As shown in FIG. 9, the integrated determination value Z1 is a level that can be measured by the level gauge 68 from the full tank of the urea water tank 65 among the levels 1 to 6 measured by the level gauge 68. The amount of urea water 67 reduced from 6 to level 5 is set. That is, it is desirable that the integrated determination value Z1 is set to the amount of decrease in urea water 67 that decreases until it can be measured by the level gauge 68 in the urea water tank 65. The integration determination value Z1 is stored in the ROM in advance.

そして、積算添加量記憶部５０１から読み出した積算添加量が積算判定値Ｚ１未満であると判定した場合には（Ｓ１３１：ＮＯ）、制御装置５０は、当該サブ処理を終了して、メインフローチャートに戻り、ステップＳ１７に進む。一方、積算添加量記憶部５０１から読み出した積算添加量が積算判定値Ｚ１以上であると判定した場合には（Ｓ１３１：ＹＥＳ）、制御装置５０は、ステップＳ１３２に進む。 Then, when it is determined that the integrated addition amount read from the integrated addition amount storage unit 501 is less than the integrated determination value Z1 (S131: NO), the control device 50 ends the sub-processing and displays the main flowchart. Return to step S17. On the other hand, when it is determined that the integrated addition amount read from the integrated addition amount storage unit 501 is equal to or greater than the integrated determination value Z1 (S131: YES), the control device 50 proceeds to step S132.

ステップＳ１３２において、制御装置５０は、上記ステップＳ１１１で計測した尿素水タンク６５内の尿素水６７の現在の残量をＲＡＭから読み出し、レベルゲージ６８によって計測可能となるレベル６（所定レベル）以上の残量であるか否かを判定する。つまり、規定濃度よりも低い濃度の尿素水又は水のレベルゲージ（残量検出装置）６８で検出できない少量補給が続いて、尿素水タンク６５内の尿素水６７がレベルゲージ６８で検出できるまで減少していないか否かを判定する。 In step S132, the control device 50 reads the current remaining amount of urea water 67 in the urea water tank 65 measured in step S111 from the RAM, and is at a level 6 (predetermined level) or higher that can be measured by the level gauge 68. Determine if it is the remaining amount. That is, a small amount of urea water having a concentration lower than the specified concentration or water level gauge (remaining amount detection device) 68 cannot be detected continuously, and the urea water 67 in the urea water tank 65 is reduced until it can be detected by the level gauge 68. Determine if not.

そして、尿素水タンク６５内の尿素水６７の現在の残量が、レベルゲージ６８によって計測可能となるレベル６（所定レベル）よりも少ない残量であると判定した場合には（Ｓ１３２：ＮＯ）、制御装置５０は、当該サブ処理を終了して、メインフローチャートに戻り、ステップＳ１７に進む。一方、尿素水タンク６５内の尿素水６７の現在の残量が、レベルゲージ６８によって計測可能となるレベル６（所定レベル）以上の残量であると判定した場合には（Ｓ１３２：ＹＥＳ）、制御装置５０は、ステップＳ１３３に進む。 Then, when it is determined that the current remaining amount of the urea water 67 in the urea water tank 65 is less than the level 6 (predetermined level) that can be measured by the level gauge 68 (S132: NO). , The control device 50 finishes the sub-processing, returns to the main flowchart, and proceeds to step S17. On the other hand, when it is determined that the current remaining amount of the urea water 67 in the urea water tank 65 is the remaining amount of level 6 (predetermined level) or higher that can be measured by the level gauge 68 (S132: YES), The control device 50 proceeds to step S133.

ステップＳ１３３において、制御装置５０は、ＲＡＭから第２補給フラグを読み出して、「ＯＮ」に設定した後、再度ＲＡＭに記憶する。続いて、ステップＳ１３４において、制御装置５０は、ＥＥＰＲＯＭの積算添加量記憶部５０１から尿素水の積算添加量を読み出す。そして、制御装置５０は、積算添加量に「０」を代入してリセットし、再度、積算添加量記憶部５０１に記憶した後、当該サブ処理を終了して、メインフローチャートに戻り、ステップＳ１７に進む。尚、第２補給フラグは、制御装置５０の起動時に、「ＯＦＦ」に設定されてＲＡＭに記憶される。 In step S133, the control device 50 reads the second supply flag from the RAM, sets it to “ON”, and then stores it in the RAM again. Subsequently, in step S134, the control device 50 reads out the cumulative addition amount of urea water from the cumulative addition amount storage unit 501 of the EEPROM. Then, the control device 50 substitutes "0" for the cumulative addition amount, resets it, stores it in the cumulative addition amount storage unit 501 again, ends the sub-processing, returns to the main flowchart, and proceeds to step S17. move on. The second replenishment flag is set to "OFF" and stored in the RAM when the control device 50 is started.

次に、図２に示すように、ステップＳ１７において、制御装置５０は、ＲＡＭから第２補給フラグを読み出し、「ＯＮ」に設定されているか否かを判定する。そして、第２補給フラグが「ＯＦＦ」に設定されていると判定した場合には（Ｓ１７：ＮＯ）、制御装置５０は、尿素水タンク６５へのレベルゲージ（残量検出装置）６８で検出できない規定濃度よりも低い濃度の尿素水又は水の少量補給はされていないと判定して、後述のステップＳ２０に進む。 Next, as shown in FIG. 2, in step S17, the control device 50 reads the second supply flag from the RAM and determines whether or not it is set to “ON”. Then, when it is determined that the second replenishment flag is set to "OFF" (S17: NO), the control device 50 cannot be detected by the level gauge (remaining amount detecting device) 68 to the urea water tank 65. It is determined that a small amount of urea water or water having a concentration lower than the specified concentration has not been replenished, and the process proceeds to step S20 described later.

一方、第２補給フラグが「ＯＮ」に設定されていると判定した場合には（Ｓ１７：ＹＥＳ）、制御装置５０は、尿素水タンク６５へのレベルゲージ６８によって検出可能となる容量の尿素水、若しくは、規定濃度よりも低い濃度の尿素水又は水の補給があったと判定して、ステップＳ１８に進む。つまり、制御装置５０は、尿素水タンク６５へのレベルゲージ（残量検出装置）６８で検出できない規定濃度よりも低い濃度の尿素水又は水の少量補給が続いていると判定して、ステップＳ１８に進む。 On the other hand, when it is determined that the second replenishment flag is set to "ON" (S17: YES), the control device 50 has a capacity of urea water that can be detected by the level gauge 68 to the urea water tank 65. Alternatively, it is determined that urea water or water having a concentration lower than the specified concentration has been replenished, and the process proceeds to step S18. That is, the control device 50 determines that the urea water tank 65 is continuously replenished with a small amount of urea water or water having a concentration lower than the specified concentration that cannot be detected by the level gauge (remaining amount detecting device) 68, and step S18. Proceed to.

ステップＳ１８において、制御装置５０は、尿素水添加弁６１によって添加（噴射）する尿素水の添加量を学習する「尿素水添加量学習処理」のサブ処理を実行した後、ステップＳ１９に進む。ここで、「尿素水添加量学習処理」のサブ処理について図６、図１０及び図１１に基づいて説明する。 In step S18, the control device 50 executes a sub-process of "urea water addition amount learning process" for learning the addition amount of urea water added (injected) by the urea water addition valve 61, and then proceeds to step S19. Here, the sub-treatment of the "urea water addition amount learning treatment" will be described with reference to FIGS. 6, 10 and 11.

図６に示すように、先ず、ステップＳ１４１において、制御装置５０は、上述した種々の検出装置からの検出信号等に基づいて、内燃機関１０の運転状態を取得して、ステップＳ１４２に進む。ステップＳ１４２において、制御装置５０は、尿素水添加弁６１によって添加（噴射）する尿素水の添加量を調整する運転条件（所定運転状態）が成立したか否かを判定する。例えば、制御装置５０は、ＳＣＲ４６の下流側に配置された排気温度検出装置３６Ｄによって検出されるＳＣＲ４６の床温が約２００℃〜４００℃で、吸気流量が安定し、車速が所定速度以上のときに、運転条件が成立したと判定する。 As shown in FIG. 6, first, in step S141, the control device 50 acquires the operating state of the internal combustion engine 10 based on the detection signals and the like from the various detection devices described above, and proceeds to step S142. In step S142, the control device 50 determines whether or not the operating condition (predetermined operating state) for adjusting the amount of urea water added (injected) by the urea water addition valve 61 is satisfied. For example, in the control device 50, when the floor temperature of the SCR46 detected by the exhaust temperature detection device 36D arranged on the downstream side of the SCR46 is about 200 ° C. to 400 ° C., the intake air flow rate is stable, and the vehicle speed is equal to or higher than a predetermined speed. In addition, it is determined that the operating conditions are satisfied.

そして、尿素水添加弁６１によって添加（噴射）する尿素水の添加量を調整する運転条件が成立していないと判定した場合には（Ｓ１４２：ＮＯ）、制御装置５０は、再度Ｓ１４２以降の処理を実行する。つまり、制御装置５０は、運転条件が成立するのを待つ。一方、尿素水添加弁６１によって添加（噴射）する尿素水の添加量を調整する運転条件が成立していると判定した場合には（Ｓ１４２：ＹＥＳ）、制御装置５０は、ステップＳ１４３に進む。 Then, when it is determined that the operating condition for adjusting the addition amount of urea water to be added (injected) by the urea water addition valve 61 is not satisfied (S142: NO), the control device 50 again performs the processing after S142. To execute. That is, the control device 50 waits for the operating conditions to be satisfied. On the other hand, when it is determined that the operating condition for adjusting the addition amount of urea water to be added (injected) by the urea water addition valve 61 is satisfied (S142: YES), the control device 50 proceeds to step S143.

ステップＳ１４３において、制御装置５０は、ＳＣＲ４６の下流側に配置された排気温度検出装置３６Ｄによって検出されるＳＣＲ４６の床温に対応する目標ＮＯｘ浄化率を図１０に示す目標ＮＯｘ浄化率特性曲線７１から取得してＲＡＭに記憶する。尚、図１０に示す目標ＮＯｘ浄化率特性曲線７１は、ＣＡＥ（Computer Aided Engineering）解析、又は、実験により予め取得され、マップや数式によりＲＯＭに予め記憶されている。 In step S143, the control device 50 sets the target NOx purification rate corresponding to the floor temperature of the SCR46 detected by the exhaust temperature detection device 36D arranged on the downstream side of the SCR46 from the target NOx purification rate characteristic curve 71 shown in FIG. Acquire and store in RAM. The target NOx purification rate characteristic curve 71 shown in FIG. 10 is acquired in advance by CAE (Computer Aided Engineering) analysis or experiment, and is stored in ROM in advance by a map or a mathematical formula.

続いて、ステップＳ１４４において、制御装置５０は、尿素水添加弁６１の上流側に配置されたＮＯｘセンサ３７Ａで検出される上流側ＮＯｘ濃度ＰＦと、ＳＣＲ４６の下流側に配置されたＮＯｘセンサ３７Ｂで検出された下流側ＮＯｘ濃度ＰＲとを検出する。そして、制御装置５０は、上流側ＮＯｘ濃度ＰＦから下流側ＮＯｘ濃度ＰＲを減算した値を上流側ＮＯｘ濃度ＰＦで除算して、実ＮＯｘ浄化率を算出し、ＲＡＭに記憶した後、ステップＳ１４５に進む。 Subsequently, in step S144, the control device 50 uses the upstream NOx concentration PF detected by the NOx sensor 37A arranged on the upstream side of the urea water addition valve 61 and the NOx sensor 37B arranged on the downstream side of the SCR46. The detected downstream NOx concentration PR is detected. Then, the control device 50 divides the value obtained by subtracting the downstream NOx concentration PR from the upstream NOx concentration PF by the upstream NOx concentration PF to calculate the actual NOx purification rate, stores it in the RAM, and then proceeds to step S145. move on.

ステップＳ１４５において、制御装置５０は、目標ＮＯｘ浄化率と実ＮＯｘ浄化率をＲＡＭから読み出し、目標ＮＯｘ浄化率から実ＮＯｘ浄化率を減算した差分Ｄが所定の差分閾値（例えば、１％〜３％である。）以上であるか否かを判定する。そして、目標ＮＯｘ浄化率から実ＮＯｘ浄化率を減算した差分Ｄが所定の差分閾値未満であると判定した場合には（Ｓ１４５：ＮＯ）、制御装置５０は、ステップＳ１４６に進む。つまり、制御装置５０は、尿素水タンク６５内の尿素水６７の品質（例えば、濃度等である。）は、許容範囲内の品質（例えば、規定濃度等である。）であると判定して、ステップＳ１４６に進む。尚、差分閾値は、予めＲＯＭに記憶されている。 In step S145, the control device 50 reads the target NOx purification rate and the actual NOx purification rate from the RAM, and the difference D obtained by subtracting the actual NOx purification rate from the target NOx purification rate is a predetermined difference threshold (for example, 1% to 3%). It is determined whether or not it is more than or equal to. Then, when it is determined that the difference D obtained by subtracting the actual NOx purification rate from the target NOx purification rate is less than the predetermined difference threshold value (S145: NO), the control device 50 proceeds to step S146. That is, the control device 50 determines that the quality (for example, concentration, etc.) of the urea water 67 in the urea water tank 65 is within the permissible range (for example, the specified concentration, etc.). , Step S146. The difference threshold is stored in the ROM in advance.

ステップＳ１４６において、制御装置５０は、ＥＥＰＲＯＭから品質異常フラグを読み出し、この品質異常フラグを「ＯＦＦ」に設定して、再度、ＥＥＰＲＯＭに記憶した後、当該サブ処理を終了して、メインフローチャートに戻り、ステップＳ１９に進む。 In step S146, the control device 50 reads the quality abnormality flag from the EEPROM, sets the quality abnormality flag to "OFF", stores the quality abnormality flag in the EEPROM again, ends the sub-processing, and returns to the main flowchart. , Step S19.

一方、目標ＮＯｘ浄化率から実ＮＯｘ浄化率を減算した差分Ｄが所定の差分閾値以上であると判定した場合には（Ｓ１４５：ＹＥＳ）、制御装置５０は、ステップＳ１４７に進む。ステップＳ１４７において、制御装置５０は、目標ＮＯｘ浄化率から実ＮＯｘ浄化率を減算した差分Ｄに単位増量値を乗算して尿素水の増量値Ａを算出する。尚、単位増量値は、予めＣＡＥ（Computer Aided Engineering）解析、又は、実験により予め取得され、ＲＯＭに記憶されている。 On the other hand, when it is determined that the difference D obtained by subtracting the actual NOx purification rate from the target NOx purification rate is equal to or greater than the predetermined difference threshold value (S145: YES), the control device 50 proceeds to step S147. In step S147, the control device 50 calculates the urea water increase value A by multiplying the difference D obtained by subtracting the actual NOx purification rate from the target NOx purification rate by the unit increase value. The unit increase value is acquired in advance by CAE (Computer Aided Engineering) analysis or experiment and stored in ROM.

そして、制御装置５０は、ＥＥＰＲＯＭの学習値記憶部５０２から尿素水添加量の学習値を読み出し、この学習値に算出した尿素水の増量値Ａ１を加算して、再度、尿素水添加弁６１から添加（噴射）される尿素水添加量の学習値として学習値記憶部５０２に記憶する。 Then, the control device 50 reads the learning value of the urea water addition amount from the learning value storage unit 502 of the EEPROM, adds the calculated urea water increase value A1 to this learning value, and again from the urea water addition valve 61. It is stored in the learning value storage unit 502 as a learning value of the amount of urea water added (injected).

例えば、図１１に示すように、時間Ｔ２１において、運転条件が成立し（Ｓ１４２:ＹＥＳ）、目標ＮＯｘ浄化率から実ＮＯｘ浄化率を減算した差分Ｄ１が所定の差分閾値以上であると判定された場合には（Ｓ１４３〜Ｓ１４５：ＹＥＳ）、制御装置５０は、差分Ｄ１に単位増量値を乗算して尿素水の増量値Ａ１を算出する。そして、制御装置５０は、ＥＥＰＲＯＭの学習値記憶部５０２から読み出した学習値が「初期添加量Ｖ１」の場合には、この「初期添加量Ｖ１」に「増量値Ａ１」を加算した「尿素水添加量Ｖ２」を算出する。続いて、制御装置５０は、「尿素水添加量Ｖ２」を尿素水添加弁６１から添加（噴射）される尿素水添加量の学習値として再度、学習値記憶部５０２に記憶する（Ｓ１４７）。 For example, as shown in FIG. 11, at time T21, the operating condition was satisfied (S142: YES), and it was determined that the difference D1 obtained by subtracting the actual NOx purification rate from the target NOx purification rate was equal to or greater than the predetermined difference threshold. In the case (S143 to S145: YES), the control device 50 multiplies the difference D1 by the unit increase value to calculate the urea water increase value A1. Then, when the learning value read from the learning value storage unit 502 of the EEPROM is the "initial addition amount V1", the control device 50 adds the "increase value A1" to the "initial addition amount V1" to "urea water". Addition amount V2 ”is calculated. Subsequently, the control device 50 stores the "urea water addition amount V2" in the learning value storage unit 502 again as a learning value of the urea water addition amount added (injected) from the urea water addition valve 61 (S147).

続いて、ステップＳ１４８において、制御装置５０は、ＥＥＰＲＯＭの学習値記憶部５０２から尿素水添加量の学習値を再度、読み出し、この学習値が異常判定閾値ＶＡ以上であるか否かを判定する。そして、ＥＥＰＲＯＭの学習値記憶部５０２から読み出した尿素水添加量の学習値が異常判定閾値ＶＡ未満であると判定した場合には（Ｓ１４８：ＮＯ）、制御装置５０は、尿素水タンク６５内の尿素水６７の品質（例えば、濃度等である。）は、許容範囲内の品質であると判定して、上記ステップＳ１４６以降の処理を実行する。 Subsequently, in step S148, the control device 50 reads the learning value of the urea water addition amount again from the learning value storage unit 502 of the EEPROM, and determines whether or not this learning value is equal to or greater than the abnormality determination threshold value VA. Then, when it is determined that the learning value of the urea water addition amount read from the learning value storage unit 502 of the EEPROM is less than the abnormality determination threshold VA (S148: NO), the control device 50 is in the urea water tank 65. The quality of the urea water 67 (for example, the concentration and the like) is determined to be within the permissible range, and the treatments after step S146 are executed.

例えば、図１１に示すように、時間Ｔ２１において、ＥＥＰＲＯＭの学習値記憶部５０２から読み出した尿素水添加量の学習値が、「初期添加量Ｖ１」に「増量値Ａ１」を加算した「尿素水添加量Ｖ２」の場合には、制御装置５０は、尿素水添加量Ｖ２は、異常判定閾値ＶＡ未満であるため（Ｓ１４８：ＮＯ）、尿素水タンク６５内の尿素水６７の品質（例えば、濃度等である。）は、許容範囲内の品質であると判定して、上記ステップＳ１４６以降の処理を実行する。 For example, as shown in FIG. 11, at time T21, the learning value of the urea water addition amount read from the learning value storage unit 502 of the EEPROM is "urea water" obtained by adding the "increase value A1" to the "initial addition amount V1". In the case of "addition amount V2", since the urea water addition amount V2 is less than the abnormality determination threshold value VA (S148: NO), the control device 50 has the quality (for example, concentration) of the urea water 67 in the urea water tank 65. Etc.), it is determined that the quality is within the permissible range, and the processes after step S146 are executed.

一方、ＥＥＰＲＯＭの学習値記憶部５０２から読み出した尿素水添加量の学習値が異常判定閾値ＶＡ以上であると判定した場合には（Ｓ１４８：ＹＥＳ）、制御装置５０は、尿素水タンク６５内の尿素水６７の品質（例えば、濃度等である。）は、許容範囲外の異常な品質（例えば、規定濃度よりも大きく低い濃度等である。）であると判定して、ステップＳ１４９に進む。ステップＳ１４９において、制御装置５０は、ＥＥＰＲＯＭから品質異常フラグを読み出し、この品質異常フラグを「ＯＮ」に設定して、再度、ＥＥＰＲＯＭに記憶した後、当該サブ処理を終了して、メインフローチャートに戻り、ステップＳ１９に進む。 On the other hand, when it is determined that the learning value of the urea water addition amount read from the learning value storage unit 502 of the EEPROM is equal to or higher than the abnormality determination threshold value VA (S148: YES), the control device 50 is in the urea water tank 65. It is determined that the quality of the urea water 67 (for example, the concentration or the like) is an abnormal quality outside the permissible range (for example, the concentration is larger or lower than the specified concentration), and the process proceeds to step S149. In step S149, the control device 50 reads the quality abnormality flag from the EEPROM, sets the quality abnormality flag to "ON", stores the quality abnormality flag in the EEPROM again, ends the sub-processing, and returns to the main flowchart. , Step S19.

例えば、図１１に示すように、時間Ｔ２２において、ＥＥＰＲＯＭの学習値記憶部５０２から読み出した尿素水添加量の学習値が、「尿素水添加量Ｖ２」に「増量値Ａ２」を加算した「尿素水添加量ＶＡ」の場合には、制御装置５０は、尿素水添加量ＶＡは、異常判定閾値ＶＡと等しいため（Ｓ１４８：ＹＥＳ）、尿素水タンク６５内の尿素水６７の品質（例えば、濃度等である。）は、許容範囲外の異常な品質（例えば、規定濃度よりも大きく低い濃度等である。）であると判定する。そして、制御装置５０は、ＥＥＰＲＯＭから品質異常フラグを読み出し、この品質異常フラグを「ＯＮ」に設定して、再度、ＥＥＰＲＯＭに記憶した後（Ｓ１４９）、当該サブ処理を終了して、メインフローチャートに戻り、ステップＳ１９に進む。 For example, as shown in FIG. 11, at time T22, the learning value of the urea water addition amount read from the learning value storage unit 502 of the EEPROM is "urea" obtained by adding the "increase value A2" to the "urea water addition amount V2". In the case of "water addition amount VA", since the urea water addition amount VA is equal to the abnormality determination threshold value VA (S148: YES), the control device 50 has the quality (for example, concentration) of the urea water 67 in the urea water tank 65. Etc.) is determined to be an abnormal quality outside the permissible range (for example, a concentration larger than or lower than the specified concentration). Then, the control device 50 reads the quality abnormality flag from the EEPROM, sets the quality abnormality flag to "ON", stores the quality abnormality flag in the EEPROM again (S149), ends the sub-processing, and displays the main flowchart. Return to step S19.

次に、図２に示すように、ステップＳ１９において、制御装置５０は、ＲＡＭから第１補給フラグを読み出して、「ＯＦＦ」に設定した後、再度ＲＡＭに記憶する。そして、制御装置５０は、ＲＡＭから第２補給フラグを読み出して、「ＯＦＦ」に設定した後、再度ＲＡＭに記憶した後、ステップＳ２０に進む。 Next, as shown in FIG. 2, in step S19, the control device 50 reads the first supply flag from the RAM, sets it to “OFF”, and then stores it in the RAM again. Then, the control device 50 reads the second replenishment flag from the RAM, sets it to “OFF”, stores it in the RAM again, and then proceeds to step S20.

ステップＳ２０において、制御装置５０は、「品質異常警告処理」のサブ処理を実行した後、当該処理を終了する。ここで、「品質異常警告処理」のサブ処理について図７に基づいて説明する。図７に示すように、先ず、ステップＳ１５１において、制御装置５０は、ＥＥＰＲＯＭから品質異常フラグを読み出し、「ＯＮ」に設定されているか否かを判定する。そして、品質異常フラグが「ＯＮ」に設定されていると判定した場合には（Ｓ１５１：ＹＥＳ）、制御装置５０は、ステップＳ１５２に進む。 In step S20, the control device 50 terminates the process after executing the sub-process of the "quality abnormality warning process". Here, the sub-processing of the "quality abnormality warning processing" will be described with reference to FIG. 7. As shown in FIG. 7, first, in step S151, the control device 50 reads the quality abnormality flag from the EEPROM and determines whether or not it is set to “ON”. Then, when it is determined that the quality abnormality flag is set to "ON" (S151: YES), the control device 50 proceeds to step S152.

ステップ１５２において、制御装置５０は、尿素水警告ランプ１５を点灯した後、当該サブ処理を終了して、メインフローチャートに戻り、当該処理を終了する。これにより、尿素水タンク６５内に貯留された尿素水６７の品質異常（例えば、規定濃度よりも大きく低い濃度等である。）をユーザに報知することができる。 In step 152, after turning on the urea water warning lamp 15, the control device 50 ends the sub-process, returns to the main flowchart, and ends the process. As a result, it is possible to notify the user of an abnormality in the quality of the urea water 67 stored in the urea water tank 65 (for example, a concentration larger or lower than the specified concentration).

一方、品質異常フラグが「ＯＦＦ」に設定されていると判定した場合には（Ｓ１５１：ＮＯ）、制御装置５０は、ステップＳ１５３に進む。ステップ１５３において、制御装置５０は、尿素水警告ランプ１５を消灯した後、当該サブ処理を終了して、メインフローチャートに戻り、当該処理を終了する。これにより、尿素水タンク６５内に規定濃度の尿素水が補給された場合には、点灯していた尿素水警告ランプ１５が消灯される。 On the other hand, if it is determined that the quality abnormality flag is set to "OFF" (S151: NO), the control device 50 proceeds to step S153. In step 153, after turning off the urea water warning lamp 15, the control device 50 ends the sub-process, returns to the main flowchart, and ends the process. As a result, when the urea water tank 65 is replenished with urea water having a specified concentration, the urea water warning lamp 15 that has been lit is turned off.

ここで、制御装置５０とＥＥＰＲＯＭの積算添加量記憶部５０１は、添加量積算装置の一例として機能する。制御装置５０は、積算量判定装置、残量判定装置、第１補給判定装置、第２補給判定装置、目標浄化率取得装置、実浄化率取得装置、運転状態検出装置、添加量調整装置、学習値判定装置、品質判定装置の一例として機能する。制御装置５０とレベルゲージ６８は、補給検出装置の一例として機能する。 Here, the control device 50 and the integrated addition amount storage unit 501 of the EEPROM function as an example of the addition amount integration device. The control device 50 includes an integrated amount determination device, a remaining amount determination device, a first supply determination device, a second supply determination device, a target purification rate acquisition device, an actual purification rate acquisition device, an operating state detection device, an addition amount adjustment device, and learning. It functions as an example of a value determination device and a quality determination device. The control device 50 and the level gauge 68 function as an example of the supply detection device.

以上詳細に説明した通り、本実施形態に係る内燃機関１０では、制御装置５０は、尿素水添加弁６１によって添加（噴射）された尿素水の添加量を積算してＥＥＰＲＯＭの積算添加量記憶部５０１に記憶する。そして、積算添加量記憶部５０１に記憶する尿素水の積算添加量が所定の積算判定値Ｚ１以上になったと判定されると共に、尿素水タンク６５内の尿素水６７の現在の残量が、レベルゲージ６８によって計測可能となるレベル６（所定レベル）以上の残量であると判定された場合には、制御装置５０は、尿素水タンク６５へレベルゲージ６８によって検出可能な容量の尿素水の補給があったと判定する。 As described in detail above, in the internal combustion engine 10 according to the present embodiment, the control device 50 integrates the addition amount of urea water added (injected) by the urea water addition valve 61, and the cumulative addition amount storage unit of EEPROM. Store in 501. Then, it is determined that the cumulative addition amount of urea water stored in the cumulative addition amount storage unit 501 is equal to or higher than the predetermined cumulative determination value Z1, and the current remaining amount of the urea water 67 in the urea water tank 65 is leveled. When it is determined that the remaining amount is level 6 (predetermined level) or higher that can be measured by the gauge 68, the control device 50 replenishes the urea water tank 65 with the amount of urea water that can be detected by the level gauge 68. It is determined that there was.

これにより、規定濃度よりも低い濃度の尿素水又は水の少量補給が続いて、尿素水タンク６５内の尿素水６７の減少をレベルゲージ６８で検出できないレベル６以上の残量であっても、積算添加量が所定の積算判定値Ｚ１以上に達する適切なタイミングで、尿素水タンク６５に尿素水の補給が行われたと判定することができる。その結果、制御装置５０は、適切なタイミングでＮＯｘ浄化率を測定して、尿素水タンク６５内に補給された尿素水６７の濃度等の品質検査を行う頻度を多くすることができる。 As a result, even if a small amount of urea water or water having a concentration lower than the specified concentration is continuously replenished and the decrease of urea water 67 in the urea water tank 65 cannot be detected by the level gauge 68, the remaining amount is level 6 or higher. It can be determined that the urea water has been replenished to the urea water tank 65 at an appropriate timing when the cumulative addition amount reaches a predetermined cumulative determination value Z1 or more. As a result, the control device 50 can measure the NOx purification rate at an appropriate timing and increase the frequency of quality inspection such as the concentration of the urea water 67 replenished in the urea water tank 65.

また、積算判定値Ｚ１は、尿素水タンク６５の満タンからレベルゲージ６８で計測可能となるレベル６〜レベル５までの尿素水６７の減少量に設定されている。つまり、尿素水タンク６５内のレベルゲージ６８によって計測することが可能となるまで減少する尿素水６７の減少量に設定されている。これにより、規定濃度よりも低い濃度の尿素水又は水の少量補給が続いて、レベルゲージ６８によって尿素水６７の減少を検出できない場合でも、制御装置５０は、尿素水タンク６５内の尿素水の濃度等の品質検査を行う必要がある尿素水の補給量に達したか否かを適切に判定することができる。 Further, the integrated determination value Z1 is set to a decrease amount of urea water 67 from level 6 to level 5 that can be measured by the level gauge 68 from the full tank of the urea water tank 65. That is, the amount of decrease in urea water 67 is set to decrease until it can be measured by the level gauge 68 in the urea water tank 65. As a result, even if a small amount of urea water or water having a concentration lower than the specified concentration is continuously replenished and the level gauge 68 cannot detect a decrease in the urea water 67, the control device 50 still uses the urea water in the urea water tank 65. It is possible to appropriately determine whether or not the amount of urea water replenished, which requires quality inspection such as concentration, has been reached.

また、尿素水タンク６５内へのレベルゲージ６８によって検出可能な尿素水の補給があった場合には、尿素水タンク６５に尿素水の補給があったと判定される。これにより、１回で通常量の尿素水の補給が行われた場合と、尿素水の積算添加量が所定の積算判定値Ｚ１以上になったと判定されると共に、尿素水タンク６５内の尿素水６７の現在の残量が、レベルゲージ６８によって計測可能となるレベル６（所定レベル）以上の残量であると判定された場合と、のいずれかにおいて、尿素水タンク６５に尿素水の補給が行われたと判定される。 When the urea water tank 65 is replenished with urea water that can be detected by the level gauge 68, it is determined that the urea water tank 65 is replenished with urea water. As a result, it is determined that the normal amount of urea water is replenished at one time and that the cumulative addition amount of urea water is equal to or higher than the predetermined cumulative determination value Z1, and the urea water in the urea water tank 65 is determined. In either the case where the current remaining amount of 67 is determined to be the remaining amount of level 6 (predetermined level) or higher that can be measured by the level gauge 68, or the case where the urea water tank 65 is replenished with urea water. It is determined that it was done.

その結果、制御装置５０は、１回で通常量の尿素水の補給が行われた場合と、尿素水の積算添加量が所定の積算判定値Ｚ１以上になったと判定されると共に、尿素水タンク６５内の尿素水６７の現在の残量が、レベルゲージ６８によって計測可能となるレベル６（所定レベル）以上の残量であると判定された場合と、のいずれかにおいて、ＮＯｘ浄化率を測定して、尿素水タンク６５内に補給された尿素水６７の濃度等の品質検査を行うことができる。従って、尿素水タンク６５内に補給された尿素水６７の濃度等の品質検査の頻度を多くして、尿素水タンク６５内の尿素水６７の品質向上を図ることが可能となり、ＮＯｘ浄化率の向上を図ることができる。 As a result, the control device 50 determines that the normal amount of urea water is replenished at one time and that the cumulative addition amount of urea water is equal to or higher than the predetermined cumulative determination value Z1 and the urea water tank. The NOx purification rate is measured in either the case where the current remaining amount of the urea water 67 in 65 is determined to be the remaining amount of level 6 (predetermined level) or higher that can be measured by the level gauge 68. Then, a quality inspection such as the concentration of the urea water 67 replenished in the urea water tank 65 can be performed. Therefore, it is possible to increase the frequency of quality inspections such as the concentration of the urea water 67 replenished in the urea water tank 65 to improve the quality of the urea water 67 in the urea water tank 65, and to improve the NOx purification rate. It can be improved.

また、制御装置５０は、目標ＮＯｘ浄化率と実ＮＯｘ浄化率の差分Ｄが差分閾値以上の場合には、差分Ｄに単位増量値を乗算して尿素水の増量値Ａを算出する。そして、制御装置５０は、ＥＥＰＲＯＭの学習値記憶部５０２から尿素水添加量の学習値を読み出し、この学習値に算出した尿素水の増量値Ａを加算して、再度、尿素水添加弁６１から添加（噴射）される尿素水添加量の学習値として学習値記憶部５０２に記憶する。その後、制御装置５０は、尿素水タンク６５に１回で通常量の尿素水の補給が行われたと判定した場合には、学習値を所定の初期添加量Ｖ１に再設定して記憶する。 Further, when the difference D between the target NOx purification rate and the actual NOx purification rate is equal to or greater than the difference threshold value, the control device 50 calculates the urea water increase value A by multiplying the difference D by the unit increase value. Then, the control device 50 reads the learning value of the urea water addition amount from the learning value storage unit 502 of the EEPROM, adds the calculated increase value A of urea water to this learning value, and again from the urea water addition valve 61. It is stored in the learning value storage unit 502 as a learning value of the amount of urea water added (injected). After that, when it is determined that the urea water tank 65 is replenished with the normal amount of urea water once, the control device 50 resets the learning value to a predetermined initial addition amount V1 and stores it.

これにより、制御装置５０は、尿素水タンク６５内に尿素水が補給されたと判定される毎に、尿素水添加弁６１の添加量を再設定することができる。従って、ＮＯｘ浄化率に対応する尿素水添加弁６１の適切な添加量を再設定することが可能となり、引いてはＮＯｘ浄化を適正に行うことができる。また、１回で通常量の尿素水の補給が行われた際には、規定濃度（例えば、３２．５％）の尿素水を補給されたものとして尿素水添加弁６１の添加量を初期添加量Ｖ１に再設定することができる。従って、尿素水添加弁６１の適切な添加量を迅速に設定することが可能となり、ＮＯｘ浄化をより適正に行うことができる。 As a result, the control device 50 can reset the addition amount of the urea water addition valve 61 every time it is determined that the urea water has been replenished in the urea water tank 65. Therefore, it is possible to reset an appropriate addition amount of the urea water addition valve 61 corresponding to the NOx purification rate, and by extension, NOx purification can be performed appropriately. Further, when the normal amount of urea water is replenished at one time, the addition amount of the urea water addition valve 61 is initially added assuming that the urea water of the specified concentration (for example, 32.5%) has been replenished. The amount can be reset to V1. Therefore, it is possible to quickly set an appropriate addition amount of the urea water addition valve 61, and NOx purification can be performed more appropriately.

また、制御装置５０は、ＥＥＰＲＯＭの学習値記憶部５０２から読み出した尿素水添加量の学習値が異常判定閾値ＶＡ以上になったと判定した場合には、尿素水タンク６５内の尿素水６７の濃度等の品質は、異常である（例えば、規定濃度よりも大きく低い濃度である等）と判定する。これにより、尿素水タンク６５内の尿素水６７の濃度等の品質異常を確実に検出することが可能となり、品質検査の精度の向上を図ることが可能となる。 Further, when the control device 50 determines that the learning value of the urea water addition amount read from the learning value storage unit 502 of the EEPROM is equal to or higher than the abnormality determination threshold VA, the concentration of the urea water 67 in the urea water tank 65 Etc. is determined to be abnormal (for example, a concentration larger than or lower than the specified concentration). As a result, it is possible to reliably detect quality abnormalities such as the concentration of urea water 67 in the urea water tank 65, and it is possible to improve the accuracy of the quality inspection.

本発明の排気ガス浄化装置は、前記実施形態で説明した構成、構造、外観、形状、処理手順等に限定されることはなく、本発明の要旨を変更しない範囲内で種々の変更、改良、追加、削除が可能である。尚、以下の説明において上記図１〜図１１の前記実施形態に係る内燃機関１０等と同一符号は、前記実施形態に係る内燃機関１０等と同一あるいは相当部分を示すものである。 The exhaust gas purifying device of the present invention is not limited to the configuration, structure, appearance, shape, treatment procedure, etc. described in the above embodiment, and various changes, improvements, and improvements are made without changing the gist of the present invention. It can be added or deleted. In the following description, the same reference numerals as those of the internal combustion engine 10 and the like according to the above embodiments of FIGS. 1 to 11 indicate the same or equivalent parts as those of the internal combustion engine 10 and the like according to the embodiment.

（Ａ）例えば、制御装置５０は、上記ステップＳ１４の処理を実行した後、ステップＳ１８の処理に進むように構成してもよい。これにより、制御装置５０は、ＳＣＲ４６の劣化に伴って尿素水添加量の学習値を再設定することが可能となり、引いてはＮＯｘ浄化をより適切に行うことができる。 (A) For example, the control device 50 may be configured to proceed to the process of step S18 after executing the process of step S14. As a result, the control device 50 can reset the learning value of the urea water addition amount as the SCR46 deteriorates, and thus NOx purification can be performed more appropriately.

（Ｂ）前記実施形態では、尿素水タンク６５内に尿素水６７を貯留したが、アンモニアを還元剤として尿素水タンク６５内に貯留するようにしてもよい。 (B) In the above embodiment, the urea water 67 is stored in the urea water tank 65, but ammonia may be stored in the urea water tank 65 as a reducing agent.

（Ｃ）前記実施形態の説明に用いた数値は一例であり、この数値に限定されるものではない。また、以上（≧）、以下（≦）、より大きい（＞）、未満（＜）等は、等号を含んでも含まなくてもよい。 (C) The numerical value used in the description of the embodiment is an example, and is not limited to this numerical value. Further, the above (≧), the following (≦), the larger (>), the less than (<), etc. may or may not include the equal sign.

１０ 内燃機関
１２ 排気通路
１２Ａ、１２Ｂ 排気管
３６Ａ〜３６Ｄ 排気温度検出装置
３７Ａ、３７Ｂ ＮＯｘセンサ
４０ 排気ガス浄化装置
４１ 上流側排気ガス浄化装置
４５ 下流側排気ガス浄化装置
４６ ＳＣＲ（選択還元触媒）
５０ 制御装置
６１ 尿素水添加弁
６５ 尿素水タンク
６７ 尿素水
６８ レベルゲージ
５０１ 積算添加量記憶部
５０２ 学習値記憶部 10 Internal combustion engine 12 Exhaust passages 12A, 12B Exhaust pipes 36A to 36D Exhaust temperature detector 37A, 37B NOx sensor 40 Exhaust gas purification device 41 Upstream exhaust gas purification device 45 Downstream exhaust gas purification device 46 SCR (selective reduction catalyst)
50 Control device 61 Urea water addition valve 65 Urea water tank 67 Urea water 68 Level gauge 501 Cumulative addition amount storage unit 502 Learning value storage unit

Claims (6)

所定濃度の還元剤溶液を貯留する還元剤タンクと、
前記還元剤タンク内の前記還元剤溶液の残量を検出する残量検出装置と、
内燃機関の排気ガス通路に配置されて前記還元剤溶液により排気ガス中のＮＯｘを選択的に浄化する選択還元触媒と、
前記排気ガス通路における前記選択還元触媒よりも上流側に配置されて、前記還元剤タンクから供給された還元剤溶液を所定時間毎に排気ガスに添加する還元剤添加弁と、
前記還元剤添加弁によって添加された還元剤溶液の添加量を積算する添加量積算装置と、
前記添加量積算装置が積算した積算添加量が所定の積算判定値以上に達したか否かを判定する積算量判定装置と、
前記還元剤タンク内の前記還元剤溶液の残量が、前記残量検出装置によって検出可能となる所定レベル以上であるか否かを判定する残量判定装置と、
前記積算量判定装置によって前記積算添加量が所定の積算判定値以上に達したと判定されると共に、前記残量判定装置によって前記還元剤溶液の残量が前記所定レベル以上であると判定された場合に、前記還元剤タンクに前記還元剤溶液の補給が行われたと判定する第１補給判定装置と、
を備えた、
排気ガス浄化装置。 A reducing agent tank that stores a reducing agent solution of a predetermined concentration,
A remaining amount detecting device for detecting the remaining amount of the reducing agent solution in the reducing agent tank, and
A selective reducing catalyst that is arranged in the exhaust gas passage of an internal combustion engine and selectively purifies NOx in the exhaust gas with the reducing agent solution.
A reducing agent addition valve arranged on the upstream side of the selective reduction catalyst in the exhaust gas passage and adding the reducing agent solution supplied from the reducing agent tank to the exhaust gas at predetermined time intervals.
An addition amount integrating device that integrates the addition amount of the reducing agent solution added by the reducing agent addition valve,
An integrated amount determination device that determines whether or not the integrated addition amount integrated by the addition amount integration device has reached a predetermined integration determination value or more.
A remaining amount determining device for determining whether or not the remaining amount of the reducing agent solution in the reducing agent tank is equal to or higher than a predetermined level that can be detected by the remaining amount detecting device.
The integrated amount determination device determines that the integrated addition amount has reached a predetermined integrated determination value or more, and the remaining amount determination device determines that the remaining amount of the reducing agent solution is equal to or higher than the predetermined level. In this case, the first replenishment determination device for determining that the reducing agent solution has been replenished to the reducing agent tank, and
With,
Exhaust gas purification device. 請求項１に記載の排気ガス浄化装置において、
前記積算判定値は、前記還元剤タンクの満タンから前記残量検出装置によって検出可能となる前記所定レベルまでの前記還元剤溶液の減少量以上に設定されている、
排気ガス浄化装置。 In the exhaust gas purification device according to claim 1,
The integrated determination value is set to be equal to or greater than the amount of decrease of the reducing agent solution from the full tank of the reducing agent tank to the predetermined level that can be detected by the remaining amount detecting device.
Exhaust gas purification device. 請求項１又は請求項２に記載の排気ガス浄化装置において、
前記残量検出装置によって前記還元剤タンク内への前記還元剤溶液の所定量以上の補給を検出する補給検出装置と、
前記補給検出装置によって前記還元剤溶液の所定量以上の補給が検出された場合に、前記還元剤タンクに前記還元剤溶液の補給が行われたと判定する第２補給判定装置と、
を備えた、
排気ガス浄化装置。 In the exhaust gas purification device according to claim 1 or 2.
A replenishment detection device that detects the replenishment of the reducing agent solution into the reducing agent tank in a predetermined amount or more by the remaining amount detecting device.
A second replenishment determination device for determining that the reducing agent solution has been replenished to the reducing agent tank when the replenishment detection device detects replenishment of the reducing agent solution in a predetermined amount or more.
With,
Exhaust gas purification device. 請求項３に記載の排気ガス浄化装置において、
前記選択還元触媒の触媒温度を検出する触媒温度検出装置と、
前記触媒温度検出装置によって検出した前記触媒温度に基づいて目標ＮＯｘ浄化率を取得する目標浄化率取得装置と、
前記選択還元触媒によって浄化された実ＮＯｘ浄化率を取得する実浄化率取得装置と、
前記内燃機関の運転状態を検出する運転状態検出装置と、
前記還元剤タンクに前記還元剤溶液の補給が行われたと判定された場合には、前記運転状態が所定運転状態になった際に、前記目標ＮＯｘ浄化率と前記実ＮＯｘ浄化率とに基づいて、前記還元剤添加弁によって添加する還元剤溶液の添加量を設定すると共に、設定された前記添加量を学習値として記憶する添加量調整装置と、
を備えた、
排気ガス浄化装置。 In the exhaust gas purification device according to claim 3,
A catalyst temperature detection device that detects the catalyst temperature of the selective reduction catalyst, and
A target purification rate acquisition device that acquires a target NOx purification rate based on the catalyst temperature detected by the catalyst temperature detection device, and a target purification rate acquisition device.
An actual purification rate acquisition device that acquires the actual NOx purification rate purified by the selective reduction catalyst,
An operating state detection device that detects the operating state of the internal combustion engine, and
When it is determined that the reducing agent solution has been replenished to the reducing agent tank, when the operating state becomes a predetermined operating state, the target NOx purification rate and the actual NOx purification rate are used as the basis. , An addition amount adjusting device that sets the addition amount of the reducing agent solution to be added by the reducing agent addition valve and stores the set addition amount as a learning value.
With,
Exhaust gas purification device. 請求項４に記載の排気ガス浄化装置において、
前記添加量調整装置は、前記第２補給判定装置を介して前記還元剤タンクに前記還元剤溶液の補給が行われたと判定された場合には、前記学習値を所定の初期添加量に再設定して記憶する、
排気ガス浄化装置。 In the exhaust gas purification device according to claim 4,
When it is determined that the reducing agent solution has been replenished to the reducing agent tank via the second replenishment determination device, the addition amount adjusting device resets the learning value to a predetermined initial addition amount. And remember
Exhaust gas purification device. 請求項４又は請求項５に記載の排気ガス浄化装置において、
前記学習値が異常判定閾値以上になったか否かを判定する学習値判定装置と、
前記学習値判定装置によって前記学習値が異常判定閾値以上になったと判定された場合には、前記還元剤タンク内の前記還元剤溶液の品質は、異常であると判定する品質判定装置と、
を備えた、
排気ガス浄化装置。 In the exhaust gas purification device according to claim 4 or 5.
A learning value determination device that determines whether or not the learning value exceeds the abnormality determination threshold value,
When it is determined by the learning value determination device that the learning value is equal to or higher than the abnormality determination threshold value, the quality of the reducing agent solution in the reducing agent tank is determined to be abnormal.
With,
Exhaust gas purification device.
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