JP2003129835A - Exhaust emission control device - Google Patents
Exhaust emission control deviceInfo
- Publication number
- JP2003129835A JP2003129835A JP2002213573A JP2002213573A JP2003129835A JP 2003129835 A JP2003129835 A JP 2003129835A JP 2002213573 A JP2002213573 A JP 2002213573A JP 2002213573 A JP2002213573 A JP 2002213573A JP 2003129835 A JP2003129835 A JP 2003129835A
- Authority
- JP
- Japan
- Prior art keywords
- amount
- oxygen
- regeneration
- oxygen amount
- filter
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 239000001301 oxygen Substances 0.000 claims abstract description 645
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 645
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 641
- 238000002485 combustion reaction Methods 0.000 claims abstract description 123
- 239000007789 gas Substances 0.000 claims abstract description 88
- 238000011069 regeneration method Methods 0.000 claims description 244
- 230000008929 regeneration Effects 0.000 claims description 241
- 239000000446 fuel Substances 0.000 claims description 125
- 238000007254 oxidation reaction Methods 0.000 claims description 34
- 238000000746 purification Methods 0.000 claims description 25
- 230000003647 oxidation Effects 0.000 claims description 24
- 239000003054 catalyst Substances 0.000 claims description 23
- 238000011144 upstream manufacturing Methods 0.000 claims description 12
- 230000008859 change Effects 0.000 claims description 11
- 238000001514 detection method Methods 0.000 claims description 9
- 238000002844 melting Methods 0.000 abstract description 10
- 230000008018 melting Effects 0.000 abstract description 10
- 238000002347 injection Methods 0.000 description 27
- 239000007924 injection Substances 0.000 description 27
- 238000010586 diagram Methods 0.000 description 12
- 230000004044 response Effects 0.000 description 11
- 238000000034 method Methods 0.000 description 9
- 230000004048 modification Effects 0.000 description 9
- 238000012986 modification Methods 0.000 description 9
- 230000002411 adverse Effects 0.000 description 8
- 230000000694 effects Effects 0.000 description 8
- 239000013618 particulate matter Substances 0.000 description 8
- 206010021143 Hypoxia Diseases 0.000 description 7
- 230000008569 process Effects 0.000 description 7
- 230000009931 harmful effect Effects 0.000 description 6
- 230000001590 oxidative effect Effects 0.000 description 6
- 239000000155 melt Substances 0.000 description 5
- 230000002950 deficient Effects 0.000 description 4
- 239000007800 oxidant agent Substances 0.000 description 4
- 239000000779 smoke Substances 0.000 description 4
- 102100029859 Zinc finger protein neuro-d4 Human genes 0.000 description 3
- 230000001133 acceleration Effects 0.000 description 2
- 230000004913 activation Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 230000003628 erosive effect Effects 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 238000005457 optimization Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 230000001052 transient effect Effects 0.000 description 2
- 102100028175 Abasic site processing protein HMCES Human genes 0.000 description 1
- 101100321670 Fagopyrum esculentum FA18 gene Proteins 0.000 description 1
- 101001006387 Homo sapiens Abasic site processing protein HMCES Proteins 0.000 description 1
- 101150044039 PF12 gene Proteins 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000004043 responsiveness Effects 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
- F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
- F01N3/023—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles
-
- 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
- F01N9/00—Electrical control of exhaust gas treating apparatus
- F01N9/002—Electrical control of exhaust gas treating apparatus of filter regeneration, e.g. detection of clogging
-
- 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
- F01N2430/00—Influencing exhaust purification, e.g. starting of catalytic reaction, filter regeneration, or the like, by controlling engine operating characteristics
- F01N2430/06—Influencing exhaust purification, e.g. starting of catalytic reaction, filter regeneration, or the like, by controlling engine operating characteristics by varying fuel-air ratio, e.g. by enriching fuel-air mixture
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
- F01N2560/06—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being a temperature sensor
-
- 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
- F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
- F01N2900/04—Methods of control or diagnosing
- F01N2900/0408—Methods of control or diagnosing using a feed-back loop
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Processes For Solid Components From Exhaust (AREA)
- Exhaust Gas After Treatment (AREA)
- Output Control And Ontrol Of Special Type Engine (AREA)
- Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
- Filtering Of Dispersed Particles In Gases (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、排ガス中に含まれ
るパティキュレートを捕集するフィルタを備えた排気浄
化装置に関し、特に、該フィルタを好適に再生するよう
にした排気浄化装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purification device provided with a filter for collecting particulates contained in exhaust gas, and more particularly to an exhaust gas purification device adapted to suitably regenerate the filter.
【０００２】[0002]
【関連する背景技術】内燃機関としてのディーゼルエン
ジン（以下、エンジンという）から排出される排ガスに
は、ＨＣ、ＣＯ、ＮＯx等のほかにパティキュレートが
多く含まれており、このパティキュレートを処理するた
めの後処理装置として、排ガス中のパティキュレートを
ディーゼル・パティキュレート・フィルタ（ＤＰＦ）で
捕捉して焼却除去する排気浄化装置が提案されている。
ＤＰＦ上でのパティキュレートの焼却除去は、ＤＰＦ温
度が所定温度以上であれば通常の運転中にも自ずと行わ
れるが、この条件が満たされない機関運転状態が継続す
ると、パティキュレートが焼却除去されずにＤＰＦでの
パティキュレート捕集量が許容量を越え、エンジンの排
気圧力が増大して機関性能が低下するなどの不具合が生
じるおそれがある。そこで、一般には、ＤＰＦを積極的
に昇温してパティキュレートの焼却除去すなわちＤＰＦ
の再生を促進する強制再生制御が実施される。2. Related Background Art Exhaust gas emitted from a diesel engine (hereinafter referred to as an engine) as an internal combustion engine contains a large amount of particulates in addition to HC, CO, NOx, etc., and the particulates are processed. As an after-treatment device for the above, an exhaust gas purification device has been proposed in which particulates in exhaust gas are captured by a diesel particulate filter (DPF) and incinerated for removal.
The incineration and removal of particulates on the DPF is naturally performed during normal operation as long as the DPF temperature is equal to or higher than a predetermined temperature. However, if this condition is not satisfied, the particulates are not incinerated and removed. Further, there is a possibility that the amount of particulates collected by the DPF exceeds the allowable amount, the exhaust pressure of the engine increases, and the engine performance deteriorates. Therefore, generally, the temperature of the DPF is positively raised to incinerate the particulates, that is, the DPF.
The forced regeneration control for promoting the regeneration of the is executed.
【０００３】強制再生制御は、ＤＰＦの前後差圧や排ガ
ス流量等から推定したパティキュレート捕集量が所定値
に達する度に実施すべきであるが、例えば機関冷態時や
低負荷低回転での機関運転時のように排気温度が低くて
パティキュレートの焼却除去に適さない条件下での機関
運転中は、強制再生制御の実施が一般には保留される。The forced regeneration control should be carried out every time the particulate collection amount estimated from the differential pressure across the DPF, the exhaust gas flow rate, etc. reaches a predetermined value. For example, when the engine is in a cold state or under low load and low rotation. The forced regeneration control is generally suspended during engine operation under conditions where the exhaust temperature is low and is not suitable for incineration and removal of particulates, such as during engine operation.
【０００４】強制再生制御に関して更に説明すると、例
えば実公平５−３６９４号公報に記載の排気浄化装置で
は、強制再生制御中、排気温度を触媒活性化温度以上に
保ってパティキュレートの焼却除去に適したフィルタ温
度を得るようにしている。また、この排気浄化装置は、
排気通路のフィルタ上流側に空気を導入するポンプを備
え、強制再生制御中、ポンプによる空気導入量を制御し
て排ガス中の酸素濃度を下限酸素濃度（再生限界酸素濃
度）と上限酸素濃度との間に保持し、これによりパティ
キュレートの焼却除去に必要な酸素を供給するようにな
っている。Explaining the forced regeneration control further, for example, in the exhaust gas purification apparatus disclosed in Japanese Utility Model Publication No. 5-3694, the exhaust temperature is kept above the catalyst activation temperature during the forced regeneration control and is suitable for incineration and removal of particulates. I am trying to get the filter temperature. Also, this exhaust purification device
A pump for introducing air is provided upstream of the filter in the exhaust passage, and during forced regeneration control, the amount of air introduced by the pump is controlled so that the oxygen concentration in the exhaust gas falls between the lower limit oxygen concentration (regeneration limit oxygen concentration) and the upper limit oxygen concentration. It is held between them to supply oxygen necessary for incineration and removal of particulates.
【０００５】[0005]
【発明が解決しようとする課題】しかし、パティキュレ
ートの焼却除去に必要な酸素量は必ずしも一定ではな
い。例えば、フィルタ温度が高い場合、フィルタ上での
パティキュレートの焼却除去が促進されるので必要酸素
量は少なくなる。また、強制再生制御の実施保留が長期
間にわたって継続してフィルタによるパティキュレート
捕集量が増大した場合も必要酸素量が少なくなる。However, the amount of oxygen required for incineration and removal of particulates is not always constant. For example, when the filter temperature is high, the incineration and removal of particulates on the filter is promoted, so that the required oxygen amount is reduced. In addition, the required oxygen amount also decreases when the forced regeneration control is continuously suspended for a long period of time and the amount of collected particulates by the filter increases.
【０００６】この点、上記の排気浄化装置は、固定的に
設定される下限酸素濃度および上限酸素濃度に基づいて
酸素濃度を制御すると共に排気温度を制御するものにな
っており、フィルタ温度やパティキュレート捕集量に適
した酸素量をフィルタに供給できないおそれがある。例
えば、パティキュレート捕集量が過剰な状況でも通常時
と同様に排気温度及び酸素濃度が制御されてしまい、パ
ティキュレートの燃焼が急激に進行して、放出された多
量の熱によりＤＰＦが溶損してしまう虞がある。In this respect, the above-mentioned exhaust gas purification device controls the oxygen concentration and the exhaust gas temperature on the basis of the fixedly set lower limit oxygen concentration and upper limit oxygen concentration. There is a possibility that the amount of oxygen suitable for the amount of collected curate cannot be supplied to the filter. For example, even when the amount of trapped particulates is excessive, the exhaust temperature and oxygen concentration are controlled as in the normal state, the combustion of particulates rapidly progresses, and the large amount of heat released causes the DPF to melt and be damaged. There is a risk that
【０００７】又、ＤＰＦの熱容量の影響により、排気温
度に対してＤＰＦ温度は遅れをもって追従することか
ら、上記公報の排気浄化装置のように排気温度を制御し
ても、ＤＰＦ温度をきめ細かく制御できるとは限らな
い。従って、例えば急加速や減速等の過渡状態ではＤＰ
Ｆ温度の制御遅れが顕著に表れ、結果として所期のパテ
ィキュレートの燃焼状態が得られずに、上記ＤＰＦの溶
損や不完全再生の要因となってしまう。Further, since the DPF temperature follows the exhaust temperature with a delay due to the influence of the heat capacity of the DPF, the DPF temperature can be finely controlled even if the exhaust temperature is controlled as in the exhaust gas purifying apparatus of the above publication. Not necessarily. Therefore, for example, in a transient state such as sudden acceleration or deceleration, DP
The control delay of the F temperature appears remarkably, and as a result, the desired particulate combustion state cannot be obtained, which causes the above-mentioned DPF to be melted and incompletely regenerated.
【０００８】本発明の目的は、フィルタを溶損させるこ
となく適正に再生することができる排気浄化装置を提供
することにある。An object of the present invention is to provide an exhaust gas purification device which can properly regenerate the filter without melting it.
【０００９】[0009]
【課題を解決するための手段】請求項１に記載の発明
は、内燃機関の排気通路に設けられて排気中のパティキ
ュレートを捕集するフィルタと該フィルタへの酸素供給
量を調整可能な酸素供給量調整要素とを有する排気浄化
装置において、フィルタ又はフィルタ近傍の温度を検出
又は推定する温度推定要素を備え、酸素供給量調整要素
は、酸素供給量を、フィルタ温度に応じて定められた再
生下限酸素量と再生上限酸素量との間の値となるように
調整することを特徴とする。According to a first aspect of the present invention, there is provided a filter provided in an exhaust passage of an internal combustion engine for collecting particulates in exhaust gas, and oxygen capable of adjusting an oxygen supply amount to the filter. In an exhaust gas purification device having a supply amount adjusting element, a temperature estimating element for detecting or estimating the temperature of the filter or the vicinity of the filter is provided, and the oxygen supply amount adjusting element regenerates the oxygen supply amount according to the filter temperature. It is characterized in that it is adjusted to a value between the lower limit oxygen amount and the regeneration upper limit oxygen amount.
【００１０】請求項１に記載の排気浄化装置では、フィ
ルタ温度に応じてそれぞれ設定された再生下限酸素量と
再生上限酸素量との間の値になるように酸素供給量が調
整される。再生下限酸素量は、例えば、フィルタの再生
を困難にする酸素不足や機関運転上の弊害（例えばスモ
ークの発生）を招く酸素不足をきたさないような酸素供
給量の下限値に対応する。また、再生上限酸素量は、例
えば、フィルタを溶損させるに至る酸素過多や機関運転
上の弊害（例えば内燃機関における失火や運転騒音の発
生または機関運転性能（ドライバビリティ）の低下）を
招く酸素過多をきたさないような酸素供給量の上限値に
対応する。In the exhaust emission control device according to the first aspect, the oxygen supply amount is adjusted so that the value is between the regeneration lower limit oxygen amount and the regeneration upper limit oxygen amount that are set according to the filter temperature. The regeneration lower limit oxygen amount corresponds to, for example, a lower limit value of the oxygen supply amount that does not cause an oxygen shortage that makes it difficult to regenerate the filter and an oxygen shortage that causes an adverse effect on engine operation (for example, generation of smoke). In addition, the regeneration upper limit oxygen amount is, for example, oxygen that causes excess oxygen that causes the filter to be melted and causes adverse effects on engine operation (for example, misfire and operation noise in the internal combustion engine, or deterioration of engine operation performance (drivability)). It corresponds to the upper limit of the oxygen supply amount that does not cause excess.
【００１１】請求項１に記載の発明によれば、酸素供給
量調整によりフィルタ温度に応じた適正量の酸素をフィ
ルタに供給することができ、これにより、フィルタ温度
の高低と無関係に常に適正量の酸素の存在下で、酸素不
足や酸素過多による弊害（スモークや失火の発生、フィ
ルタの溶損など）を防止しつつ、フィルタを再生するこ
とができる。According to the first aspect of the present invention, by adjusting the oxygen supply amount, it is possible to supply an appropriate amount of oxygen to the filter, which makes it possible to always supply the appropriate amount of oxygen regardless of whether the filter temperature is high or low. In the presence of oxygen, the filter can be regenerated while preventing harmful effects due to lack of oxygen or excess oxygen (occurrence of smoke, misfire, erosion of filter, etc.).
【００１２】請求項２に記載の発明は、酸素供給量を内
燃機関の燃焼状態に対応する排気中の残存酸素量から求
めることを特徴とする。請求項２に記載の発明では、排
気中の残存酸素量を勘案してフィルタへの酸素供給量を
調整する。通常、内燃機関に供給された吸入空気はその
大部分が燃料の燃焼に供されて消費されるが、消費され
なかった空気は内燃機関から排出されて排気中の残存酸
素となり、フィルタへの酸素供給量の少なくとも一部を
構成する。従って、機関の燃焼状態に応じて変化する排
気中の残存酸素量を勘案することにより、フィルタへの
酸素供給量をより適正に調整することができる。The invention according to claim 2 is characterized in that the oxygen supply amount is obtained from the residual oxygen amount in the exhaust gas corresponding to the combustion state of the internal combustion engine. According to the second aspect of the invention, the oxygen supply amount to the filter is adjusted in consideration of the residual oxygen amount in the exhaust gas. Normally, most of the intake air supplied to the internal combustion engine is consumed by the combustion of fuel and consumed, but the unconsumed air is discharged from the internal combustion engine and becomes the residual oxygen in the exhaust gas, which is oxygen to the filter. It constitutes at least part of the supply. Therefore, the oxygen supply amount to the filter can be adjusted more appropriately by considering the residual oxygen amount in the exhaust gas which changes according to the combustion state of the engine.
【００１３】請求項３に記載の発明は、再生下限酸素量
と再生上限酸素量との間でフィルタ温度に応じて最適酸
素量を求め、酸素供給量を最適酸素量となるように又は
最適酸素量に近づくように調整することを特徴とする。According to the third aspect of the present invention, the optimum oxygen amount is determined between the lower limit regeneration oxygen amount and the upper limit regeneration oxygen amount in accordance with the filter temperature, and the oxygen supply amount is set to the optimum oxygen amount or the optimum oxygen amount is set. It is characterized by adjusting so as to approach the quantity.
【００１４】請求項３に記載の発明によれば、フィルタ
への酸素供給量を最適化することができ、酸素不足や酸
素過多による弊害をより確実に防止しつつ、フィルタの
再生をより良好に実施することができる。According to the third aspect of the present invention, the amount of oxygen supplied to the filter can be optimized, and the adverse effects of oxygen deficiency and excess oxygen can be more reliably prevented, and the regeneration of the filter can be improved. It can be carried out.
【００１５】請求項４に記載の発明は、最適酸素量が再
生下限酸素量と再生上限酸素量との中間値近傍の値又は
該中間値よりも再生下限酸素量側の値に設定されること
を特徴とする。According to a fourth aspect of the present invention, the optimum oxygen amount is set to a value near an intermediate value between the lower limit regeneration oxygen amount and the upper limit regeneration oxygen amount or a value closer to the lower limit regeneration oxygen amount than the intermediate value. Is characterized by.
【００１６】請求項４に記載の発明では、フィルタへの
酸素供給量を再生下限酸素量と再生上限酸素量との中間
値近傍の値になるように調整して、酸素不足や酸素過多
による弊害、特に酸素過多によるフィルタの溶損が生じ
るおそれを解消し又は大幅に低減することができる。According to the fourth aspect of the invention, the oxygen supply amount to the filter is adjusted so as to be a value in the vicinity of the intermediate value between the regeneration lower limit oxygen amount and the regeneration upper limit oxygen amount, and there is a problem due to oxygen deficiency or excess oxygen. In particular, it is possible to eliminate or significantly reduce the possibility that the filter will be melted due to excess oxygen.
【００１７】請求項５に記載の発明は、最適酸素量が第
１最適酸素量とこれよりも大きい第２最適酸素量との間
の所定範囲を有し、また、酸素供給量調整要素が、内燃
機関の燃焼状態に対応する排気中の残存酸素量に応じて
酸素供給量を求め、酸素供給量が最適酸素量の所定範囲
外にあるときには酸素供給量を第１最適酸素量と第２最
適酸素量のうちの近接した方になるように調整すること
を特徴とする。According to a fifth aspect of the present invention, the optimum oxygen amount has a predetermined range between the first optimum oxygen amount and a second optimum oxygen amount larger than the first optimum oxygen amount, and the oxygen supply amount adjusting element includes: The oxygen supply amount is obtained according to the residual oxygen amount in the exhaust gas corresponding to the combustion state of the internal combustion engine, and when the oxygen supply amount is outside the predetermined range of the optimum oxygen amount, the oxygen supply amount is set to the first optimum oxygen amount and the second optimum oxygen amount. It is characterized in that the oxygen amount is adjusted to be closer to one another.
【００１８】請求項５に記載の発明では、排気中の残存
酸素量を勘案して酸素供給量を求め、次に、最適酸素量
の所定範囲内に入るように酸素供給量を調整するので、
フィルタへの酸素供給量を最適化してフィルタの再生を
良好に行える。また、酸素供給量の調整に際して、排気
中の残存酸素量に対応する酸素供給量が最適酸素量の所
定範囲外であれば酸素供給量が所定範囲内に入るように
最小限の調整を行い、酸素供給量が最適酸素量の所定範
囲内であれば調整を行わない。この様に、酸素供給量の
調整を必要最小限に留めるので、フィルタ再生に伴う機
関運転状態の変化を低減して、円滑な機関運転を阻害す
るおそれを解消し或いは大幅に低減することができる。According to the fifth aspect of the invention, the oxygen supply amount is determined in consideration of the residual oxygen amount in the exhaust gas, and then the oxygen supply amount is adjusted so as to fall within the predetermined range of the optimum oxygen amount.
Optimizing the amount of oxygen supplied to the filter enables good regeneration of the filter. Further, when adjusting the oxygen supply amount, if the oxygen supply amount corresponding to the residual oxygen amount in the exhaust gas is outside the predetermined range of the optimum oxygen amount, the minimum adjustment is performed so that the oxygen supply amount falls within the predetermined range, If the oxygen supply amount is within the predetermined range of the optimum oxygen amount, the adjustment is not performed. In this way, since the adjustment of the oxygen supply amount is kept to the necessary minimum, it is possible to reduce the change in the engine operating state due to the filter regeneration, and to eliminate or significantly reduce the possibility of disturbing the smooth engine operation. .
【００１９】請求項６に記載の発明は、内燃機関が下限
空燃比及び上限空燃比で運転される際のそれぞれの燃焼
状態に対応する排気中の第１及び第２残存酸素量を求
め、最適酸素量と第１，第２残存酸素量とを比較し、こ
の比較結果に応じて上記酸素供給量を調整することを特
徴とする。According to a sixth aspect of the present invention, the first and second residual oxygen amounts in the exhaust gas corresponding to respective combustion states when the internal combustion engine is operated at the lower limit air-fuel ratio and the upper limit air-fuel ratio are determined, and the optimum value is obtained. It is characterized in that the oxygen amount is compared with the first and second residual oxygen amounts, and the oxygen supply amount is adjusted according to the comparison result.
【００２０】請求項６に記載の発明によれば、フィルタ
の再生に際して、必要最小限の酸素供給量の調整を行う
ことによりフィルタへの酸素供給量を最適酸素量に近づ
けることができ、また、下限空燃比以上かつ上限空燃比
以下の空燃比で内燃機関を運転することができる。従っ
て、適正量の酸素の存在下でフィルタ再生を良好に行え
ることはもとより、例えば、円滑な機関運転を維持可能
な空燃比領域の下限値及び上限値にそれぞれ対応するよ
うに下限空燃比及び上限空燃比を設定することによりフ
ィルタ再生中も内燃機関を円滑に運転することができ
る。According to the sixth aspect of the present invention, when the filter is regenerated, the oxygen supply amount to the filter can be approximated to the optimum oxygen amount by adjusting the necessary minimum oxygen supply amount. The internal combustion engine can be operated at an air-fuel ratio that is equal to or higher than the lower limit air-fuel ratio and equal to or lower than the upper limit air-fuel ratio. Therefore, in addition to being able to favorably perform filter regeneration in the presence of an appropriate amount of oxygen, for example, the lower limit air-fuel ratio and the upper limit are set so as to correspond to the lower limit value and the upper limit value of the air-fuel ratio region that can maintain smooth engine operation. By setting the air-fuel ratio, the internal combustion engine can be operated smoothly even during filter regeneration.
【００２１】請求項７に記載の発明は、最適酸素量が第
１残存酸素量と第２残存酸素量との間にある場合には酸
素供給量を最適酸素量となるように調整することを特徴
とする。According to a seventh aspect of the present invention, when the optimum oxygen amount is between the first residual oxygen amount and the second residual oxygen amount, the oxygen supply amount is adjusted to be the optimum oxygen amount. Characterize.
【００２２】請求項７に記載の発明では、最適酸素量を
得るように機関運転状態を変化させて（例えば下限空燃
比と上限空燃比との間で空燃比を可変して）フィルタへ
の酸素供給量を最適化して最適なフィルタ再生を行え
る。In the invention described in claim 7, the oxygen to the filter is changed by changing the engine operating condition so as to obtain the optimum oxygen amount (for example, by changing the air-fuel ratio between the lower limit air-fuel ratio and the upper limit air-fuel ratio). Optimum supply amount enables optimum filter regeneration.
【００２３】請求項８に記載の発明は、最適酸素量が第
１残存酸素量と第２残存酸素量との間にない場合には、
酸素供給量調整要素が酸素供給量を第１残存酸素量と第
２残存酸素量のうち最適酸素量に近い方になるように調
整することを特徴とする。In the invention described in claim 8, when the optimum oxygen amount is not between the first residual oxygen amount and the second residual oxygen amount,
It is characterized in that the oxygen supply amount adjusting element adjusts the oxygen supply amount so that it is closer to the optimum oxygen amount of the first residual oxygen amount and the second residual oxygen amount.
【００２４】請求項８に記載の発明では、第１または第
２残存酸素量を得るように機関運転状態を変化させて
（例えば下限空燃比または上限空燃比で内燃機関を運転
して）機関運転の円滑さを損なうことなしにフィルタ再
生を行える。According to the invention described in claim 8, the engine is operated by changing the engine operating state so as to obtain the first or second residual oxygen amount (for example, operating the internal combustion engine at the lower limit air-fuel ratio or the upper limit air-fuel ratio). Filter regeneration can be performed without impairing the smoothness of
【００２５】請求項９に記載の発明は、最適酸素量が第
１残存酸素量と第２残存酸素量との間になく且つ第１残
存酸素量と第２残存酸素量が再生下限酸素量と再生上限
酸素量との間にない場合には、酸素供給量を再生下限酸
素量と再生上限酸素量のうち第１残存酸素量または第２
残存酸素量に近い方になるように調整することを特徴と
する。In the invention described in claim 9, the optimum oxygen amount is not between the first residual oxygen amount and the second residual oxygen amount, and the first residual oxygen amount and the second residual oxygen amount are the regeneration lower limit oxygen amount. If it is not within the regeneration upper limit oxygen amount, the oxygen supply amount is set to the first remaining oxygen amount or the second upper limit oxygen amount of the regeneration lower limit oxygen amount and the regeneration upper limit oxygen amount.
The feature is that the amount of oxygen is adjusted to be closer to the residual oxygen amount.
【００２６】請求項９に記載の発明では、再生下限酸素
量または再生上限酸素量を得るように機関運転状態を変
化させて（例えば空燃比を調整して）フィルタ再生を行
うことができる。According to the ninth aspect of the present invention, the filter regeneration can be performed by changing the engine operating condition (for example, adjusting the air-fuel ratio) so as to obtain the regeneration lower limit oxygen amount or the regeneration upper limit oxygen amount.
【００２７】請求項１０に記載の発明は、再生下限酸素
量が第１再生下限酸素量とこれよりも大きい第２再生下
限酸素量との間の所定範囲を有し、再生上限酸素量が第
１再生上限酸素量とこれよりも大きい第２再生上限酸素
量との間の所定範囲を有し、内燃機関の燃焼状態に対応
する排気中の残存酸素量から酸素供給量を求め、酸素供
給量が第１再生下限酸素量よりも小さいときには酸素供
給量を第１再生下限酸素量となるように調整し、酸素供
給量が再生下限酸素量の所定範囲内にあるときには酸素
供給量を第２再生下限酸素量となるように調整し、酸素
供給量が再生上限酸素量の所定範囲内にあるときには酸
素供給量を第１再生上限酸素量となるように調整し、酸
素供給量が第２再生上限酸素量よりも大きいときには酸
素供給量を第２再生上限酸素量となるように調整するこ
とを特徴とする。According to a tenth aspect of the present invention, the lower limit of regeneration oxygen amount has a predetermined range between the first lower limit of regeneration oxygen amount and the second lower limit of regeneration oxygen amount larger than this, and the upper limit of regeneration oxygen amount is The oxygen supply amount is obtained from the residual oxygen amount in the exhaust gas that corresponds to the combustion state of the internal combustion engine and has a predetermined range between the first regeneration upper limit oxygen amount and the second regeneration upper limit oxygen amount that is larger than the first regeneration upper limit oxygen amount. Is smaller than the first regeneration lower limit oxygen amount, the oxygen supply amount is adjusted to be the first regeneration lower limit oxygen amount, and when the oxygen supply amount is within a predetermined range of the regeneration lower limit oxygen amount, the oxygen supply amount is regenerated to the second regeneration. The lower limit oxygen amount is adjusted, and when the oxygen supply amount is within the predetermined range of the regeneration upper limit oxygen amount, the oxygen supply amount is adjusted to be the first regeneration upper limit oxygen amount, and the oxygen supply amount is adjusted to the second regeneration upper limit. When it is larger than the oxygen amount, the oxygen supply amount is changed to the second And adjusting so that the upper limit of the amount of oxygen.
【００２８】請求項１０に記載の発明によれば、燃焼状
態に対応する排気中の残存酸素量を勘案して酸素供給量
が求められ、これにより適正な酸素供給量を得ると共に
酸素供給量の調整を適正に行うことができる。また、酸
素供給量が、第１、第２再生下限酸素量により定まる再
生下限酸素量の所定範囲内または第１、第２再生上限酸
素量により定まる再生上限酸素量の所定範囲内に入るか
否かに応じて、第１または第２再生下限酸素量あるいは
第１または第２再生上限酸素量になるように酸素供給量
が調整され、これにより酸素供給量の調整を最小限に抑
制することができ、フィルタ再生に伴う機関運転状態の
変化を最小限に抑制することができる。According to the tenth aspect of the present invention, the oxygen supply amount is determined in consideration of the residual oxygen amount in the exhaust gas corresponding to the combustion state, and thereby the appropriate oxygen supply amount is obtained and the oxygen supply amount Adjustment can be performed properly. Whether or not the oxygen supply amount falls within a predetermined range of the lower limit of regeneration oxygen determined by the first and second lower limit of regeneration or within a predetermined range of the upper limit of oxygen regeneration determined by the first and second upper limit of regeneration oxygen Depending on whether the oxygen supply amount is adjusted to the first or second regeneration lower limit oxygen amount or the first or second regeneration upper limit oxygen amount, adjustment of the oxygen supply amount can be suppressed to the minimum. Therefore, it is possible to minimize the change in the engine operating state due to the filter regeneration.
【００２９】請求項１１に記載の発明は、フィルタによ
るパティキュレート捕集量を推定し、この推定されたパ
ティキュレート捕集量とフィルタ温度とに応じて再生下
限酸素量および再生上限酸素量を設定することを特徴と
する。According to the eleventh aspect of the present invention, the amount of particulates collected by the filter is estimated, and the lower limit of regeneration oxygen amount and the upper limit of regeneration oxygen amount are set according to the estimated amount of particulates trapped and the filter temperature. It is characterized by doing.
【００３０】請求項１１に記載の発明によれば、再生下
限酸素量および再生上限酸素量ひいてはフィルタへの酸
素供給量がフィルタ温度と推定パティキュレート捕集量
とに応じて設定され、これにより、フィルタ温度の高低
やパティキュレート捕集量の大小と無関係に常に適正量
の酸素の存在下で酸素不足や酸素過多による弊害を回避
しつつフィルタを再生することができる。特に、パティ
キュレート捕集量が多い場合にも、適正量の酸素をフィ
ルタに供給でき、過度の酸素供給に起因するフィルタ溶
損を確実に防止することができる。According to the eleventh aspect of the present invention, the regeneration lower limit oxygen amount and the regeneration upper limit oxygen amount and thus the oxygen supply amount to the filter are set in accordance with the filter temperature and the estimated particulate trapping amount. Regardless of whether the filter temperature is high or low and the amount of particulate collection, the filter can be regenerated in the presence of an appropriate amount of oxygen, while avoiding the harmful effects of insufficient oxygen or excess oxygen. In particular, even when the particulate collection amount is large, it is possible to supply an appropriate amount of oxygen to the filter, and it is possible to reliably prevent filter melting loss due to excessive oxygen supply.
【００３１】請求項１２に記載の発明は、推定されたパ
ティキュレート捕集量が所定量以上で且つ上記内燃機関
が所定運転状態であるときに、酸素供給量を調整するこ
とを特徴とする。The invention described in claim 12 is characterized in that the oxygen supply amount is adjusted when the estimated particulate matter trapping amount is equal to or more than a predetermined amount and the internal combustion engine is in a predetermined operating state.
【００３２】請求項１２に記載の発明によれば、内燃機
関が所定運転状態以外の運転状態にあって、たとえばフ
ィルタ温度が過度に低くて適正量の酸素の存在下でもフ
ィルタを十分に再生できないおそれがある場合には、酸
素供給量調整要素を非作動化してフィルタ再生を不実施
とする。この結果、推定パティキュレート捕集量が所定
量を上回ってもフィルタ再生が行われないことがある
が、その後、内燃機関が所定運転状態になると、推定パ
ティキュレート捕集量に適した量の酸素の存在下で、酸
素不足や酸素過多による弊害を回避しつつフィルタを再
生することができる。According to the twelfth aspect of the present invention, when the internal combustion engine is in an operating state other than the predetermined operating state, for example, the filter temperature is excessively low and the filter cannot be sufficiently regenerated even in the presence of a proper amount of oxygen. If there is a risk, deactivate the oxygen supply amount adjusting element to discontinue the filter regeneration. As a result, filter regeneration may not be performed even if the estimated particulate matter collection amount exceeds the predetermined amount, but when the internal combustion engine then enters the predetermined operating state, the amount of oxygen suitable for the estimated particulate matter collection amount is increased. In the presence of, the filter can be regenerated while avoiding the harmful effects of oxygen deficiency or excess oxygen.
【００３３】請求項１３に記載の発明は、フィルタ又は
フィルタ近傍の温度を検出する温度検出要素の検出出力
と該検出出力の変化とに基づいてフィルタ又はフィルタ
近傍の温度を推定することを特徴とする。According to a thirteenth aspect of the present invention, the temperature of the filter or the vicinity of the filter is estimated based on the detected output of the temperature detecting element for detecting the temperature of the filter or the vicinity of the filter and the change in the detected output. To do.
【００３４】請求項１３に記載の発明では、フィルタ又
はフィルタ近傍の温度を検出する温度検出手段の検出出
力をそのままフィルタ温度として用いることなく、検出
出力とその変化とに基づいて推定したフィルタ温度を酸
素供給量の調整に適用するので、温度検出手段の応答遅
れの影響による検出温度誤差を除去することができる。According to the thirteenth aspect of the invention, the filter temperature estimated based on the detected output and its change is used without directly using the detected output of the temperature detecting means for detecting the temperature of the filter or the vicinity of the filter as the filter temperature. Since this is applied to the adjustment of the oxygen supply amount, it is possible to eliminate the detected temperature error due to the influence of the response delay of the temperature detecting means.
【００３５】請求項１４に記載の発明は、フィルタが、
フィルタ中又はフィルタよりも上流の排気通路に配設さ
れる酸化触媒の酸化反応を利用して再生可能とされるこ
とを特徴とする。According to a fourteenth aspect of the invention, the filter is
It is characterized in that it can be regenerated by utilizing the oxidation reaction of the oxidation catalyst arranged in the filter or in the exhaust passage upstream of the filter.
【００３６】請求項１４に記載の発明によれば、酸化触
媒の酸化反応を利用することにより、例えば酸化触媒の
酸化反応による発熱により排気温度を昇温してフィルタ
温度を高めたり、酸化触媒が排気中の成分を酸化させて
生成される酸化剤をフィルタに供給することができ、良
好なフィルタ再生を実施することができる。According to the fourteenth aspect of the present invention, by utilizing the oxidation reaction of the oxidation catalyst, the exhaust gas temperature is raised by the heat generated by the oxidation reaction of the oxidation catalyst to raise the filter temperature, and the oxidation catalyst is The oxidant produced by oxidizing the components in the exhaust gas can be supplied to the filter, and good filter regeneration can be performed.
【００３７】[0037]
【発明の実施の形態】以下、内燃機関としてのコモンレ
ール式ディーゼルエンジン（以下、エンジンという）に
適用される本発明の第１実施形態による排気浄化装置を
説明する。BEST MODE FOR CARRYING OUT THE INVENTION An exhaust emission control device according to a first embodiment of the present invention applied to a common rail type diesel engine (hereinafter referred to as an engine) as an internal combustion engine will be described below.
【００３８】図１において、エンジン１は、例えば直列
４気筒エンジンとして構成され、その各気筒には電磁式
の燃料噴射ノズル２が設けられている。図示しないが、
各燃料噴射ノズル２は共通のコモンレールに接続されて
おり、燃料噴射ノズル２の開弁に応じて、コモンレール
内に蓄圧された高圧燃料が燃料噴射ノズル２から燃焼室
内に噴射されるようになっている。In FIG. 1, an engine 1 is constructed as, for example, an in-line four-cylinder engine, and each cylinder is provided with an electromagnetic fuel injection nozzle 2. Although not shown,
Each fuel injection nozzle 2 is connected to a common common rail, and in response to the opening of the fuel injection nozzle 2, the high pressure fuel accumulated in the common rail is injected from the fuel injection nozzle 2 into the combustion chamber. There is.
【００３９】エンジン１の吸気通路３には、上流側よ
り、エアフローセンサ４、ターボチャージャ５のコンプ
レッサ５ａ、インタークーラ６、吸気絞り弁７が設けら
れている。又、排気通路８には、上流側より、ターボチ
ャージャ５のタービン５ｂ、酸化触媒９、上流側温度セ
ンサ１０ａ、上流側圧力センサ１１ａ、フィルタとして
のＤＰＦ（ディーゼル・パティキュレート・フィルタ）
１２、下流側圧力センサ１１ｂ、下流側温度センサ１０
ｂ、排気絞り弁１３が設けられている。ターボチャージ
ャ５のコンプレッサ５ａとタービン５ｂは同一の軸に結
合されている。In the intake passage 3 of the engine 1, an air flow sensor 4, a compressor 5a of a turbocharger 5, an intercooler 6, and an intake throttle valve 7 are provided from the upstream side. Further, in the exhaust passage 8, from the upstream side, the turbine 5b of the turbocharger 5, the oxidation catalyst 9, the upstream temperature sensor 10a, the upstream pressure sensor 11a, and a DPF (diesel particulate filter) as a filter.
12, downstream pressure sensor 11b, downstream temperature sensor 10
b, an exhaust throttle valve 13 is provided. The compressor 5a and the turbine 5b of the turbocharger 5 are connected to the same shaft.
【００４０】前記酸化触媒９とＤＰＦ１２により、所謂
連続再生式ＤＰＦと呼ばれる後処理装置１４が構成さ
れ、この後処理装置１４は、酸化触媒９の酸化反応を利
用して下流のＤＰＦ１２に捕集されたパティキュレート
を常時連続的に焼却除去することができるように構成さ
れている。The oxidation catalyst 9 and the DPF 12 constitute a post-treatment device 14 called a so-called continuous regeneration type DPF. The post-treatment device 14 is collected in the downstream DPF 12 by utilizing the oxidation reaction of the oxidation catalyst 9. The particulates can be burned and removed continuously at all times.
【００４１】又、前記吸気通路３の吸気絞り弁７より下
流位置と前記排気通路８のタービン５ｂより上流位置と
はＥＧＲ通路１５により接続され、このＥＧＲ通路１５
を経て排ガスがＥＧＲガスとして吸気通路３側に還流さ
れるようになっている。ＥＧＲ通路１５にはＥＧＲ弁１
６とＥＧＲクーラ１７とが設けられ、ＥＧＲ弁１６の開
度に応じて前記ＥＧＲガスの還流量が調整されるように
なっている。An EGR passage 15 connects the position of the intake passage 3 downstream of the intake throttle valve 7 and the position of the exhaust passage 8 upstream of the turbine 5b.
After passing through, the exhaust gas is recirculated to the intake passage 3 side as EGR gas. The EGR valve 1 is installed in the EGR passage 15.
6 and an EGR cooler 17 are provided, and the recirculation amount of the EGR gas is adjusted according to the opening degree of the EGR valve 16.
【００４２】一方、図示しない入出力装置、制御プログ
ラムや制御マップ等の記憶に供される記憶装置（ＲＯ
Ｍ，ＲＡＭ等）、中央処理装置（ＣＰＵ）、タイマカウ
ンタ等を備えたＥＣＵ（電子制御ユニット）２１が設置
されている。ＥＣＵ２１の入力側には、アクセル操作量
θaccを検出するアクセルセンサ２２、エンジン回転速
度Ｎeを検出する回転速度センサ２３、前記エアフロー
センサ４、温度検出要素としての上流側と下流側の温度
センサ１０ａ，１０ｂ及び圧力センサ１１ａ，１１ｂ等
の各種センサ類が接続され、出力側には前記燃料噴射ノ
ズル２、吸気絞り弁７、排気絞り弁１３、ＥＧＲ弁１６
等の各種デバイス類が接続されている。On the other hand, an input / output device (not shown), a storage device (RO for storage of control programs, control maps, etc.)
An ECU (electronic control unit) 21 including a central processing unit (CPU), a timer counter, and the like is installed. On the input side of the ECU 21, an accelerator sensor 22 for detecting an accelerator operation amount θacc, a rotation speed sensor 23 for detecting an engine rotation speed Ne, the air flow sensor 4, upstream and downstream temperature sensors 10a as temperature detecting elements, Various sensors such as 10b and pressure sensors 11a and 11b are connected, and the fuel injection nozzle 2, the intake throttle valve 7, the exhaust throttle valve 13, the EGR valve 16 are provided on the output side.
Various devices such as are connected.
【００４３】ＥＣＵ２１はセンサ類からの検出情報に基
づいて燃料噴射ノズル２による燃料噴射量や噴射時期を
制御すると共に、吸気絞り弁７の開度を制御して吸入空
気量を制御し、また、ＥＧＲ弁１６の開度を制御してＥ
ＧＲ還流量を制御し、これによりエンジン１を適正領域
で運転させる。The ECU 21 controls the fuel injection amount and injection timing by the fuel injection nozzle 2 based on the detection information from the sensors, controls the opening of the intake throttle valve 7 to control the intake air amount, and By controlling the opening degree of the EGR valve 16, E
The GR recirculation amount is controlled so that the engine 1 is operated in the proper range.
【００４４】ＥＣＵ２１による吸入空気量及びＥＧＲ還
流量の制御に伴いＤＰＦ１２への酸素供給量が変化す
る。換言すれば、ＥＣＵ２１は、吸気絞り弁７及びＥＧ
Ｒ弁１６と共に酸素供給量調整要素を構成する。The oxygen supply amount to the DPF 12 changes as the intake air amount and the EGR recirculation amount are controlled by the ECU 21. In other words, the ECU 21 controls the intake throttle valve 7 and the EG.
An oxygen supply amount adjusting element is configured together with the R valve 16.
【００４５】排ガスに含有されたパティキュレートは後
処理装置１４のＤＰＦ１２により捕捉される。そして、
ＤＰＦ温度が所定温度（たとえば５５０℃）以上になる
と、捕捉されたパティキュレートはＤＰＦ１２上で連続
的に焼却除去され、これにより大気中へのパティキュレ
ートの排出が防止される。この様なＤＰＦの自己再生が
行われる間、酸素供給量調整要素は、ＤＰＦ１２が適正
に再生されるようにＤＰＦ１２への酸素供給量を調整す
る。The particulates contained in the exhaust gas are captured by the DPF 12 of the post-treatment device 14. And
When the DPF temperature becomes equal to or higher than a predetermined temperature (for example, 550 ° C.), the trapped particulates are continuously incinerated and removed on the DPF 12, thereby preventing the particulates from being discharged into the atmosphere. During such self-regeneration of the DPF, the oxygen supply amount adjustment element adjusts the oxygen supply amount to the DPF 12 so that the DPF 12 is properly regenerated.
【００４６】又、このような連続再生作用が得られない
運転状態が継続するとＤＰＦ１２によるパティキュレー
ト捕集量が次第に増加する。本実施形態では、ＤＰＦ温
度が例えば５５０℃未満であってＤＰＦ１２の自己再生
が良好に行われない場合、パティキュレート捕集量が所
定量以上であると共に排気温度が所定温度以上であると
き、パティキュレートを強制的に焼却除去する強制再生
制御が実施され、また、ＤＰＦ１２への酸素供給量の調
整が行われる。一方、所定のパティキュレート捕集量に
達した場合にも排気温度が所定温度未満であれば強制再
生制御は実施されない。Further, if such an operating state where the continuous regeneration action is not obtained continues, the amount of particulates collected by the DPF 12 gradually increases. In the present embodiment, when the DPF temperature is, for example, less than 550 ° C. and the self-regeneration of the DPF 12 is not performed well, when the particulate collection amount is a predetermined amount or more and the exhaust gas temperature is the predetermined temperature or more, Forced regeneration control for forcibly removing the curate by incineration is performed, and the oxygen supply amount to the DPF 12 is adjusted. On the other hand, if the exhaust gas temperature is lower than the predetermined temperature even when the predetermined particulate collection amount is reached, the forced regeneration control is not executed.
【００４７】詳しくは、本実施形態では、強制再生制御
として、通常の燃料噴射（主噴射）の後に、膨張行程或
いは排気行程において追加燃料を噴射するポスト噴射を
実施している。このポスト噴射は、まず、膨張行程側で
実施されて、追加燃料を未燃燃料（ＨＣ，ＣＯ等）とし
て排気中の酸素と反応させて、排気昇温による酸化触媒
９の活性化を図る。More specifically, in the present embodiment, as the forced regeneration control, after the normal fuel injection (main injection), the post injection for injecting the additional fuel in the expansion stroke or the exhaust stroke is executed. This post-injection is first carried out on the expansion stroke side to react the additional fuel as unburned fuel (HC, CO, etc.) with oxygen in the exhaust gas to activate the oxidation catalyst 9 by raising the temperature of the exhaust gas.
【００４８】その後、ポスト噴射時期を排気行程側に切
換えて、未燃燃料（ＨＣ，ＣＯ等）を酸化触媒９に供給
して該未燃燃料を酸化触媒９上で酸化させ、この酸化反
応による反応熱（酸化熱）によりＤＰＦ１２の温度を高
めて、ＤＰＦ２１の自己再生が行われる所定温度までＤ
ＰＦ１２を昇温させてＤＰＦ１２を活性化させ、ＤＰＦ
１２上でパティキュレートを燃焼除去する。After that, the post injection timing is switched to the exhaust stroke side, unburned fuel (HC, CO, etc.) is supplied to the oxidation catalyst 9 to oxidize the unburned fuel on the oxidation catalyst 9, and this oxidation reaction causes The temperature of the DPF 12 is raised by the heat of reaction (heat of oxidation) to a predetermined temperature at which the DPF 21 self-regenerates.
PF12 is heated to activate DPF12,
Burn out particulates on 12.
【００４９】なお、副次的には、酸化触媒９の活性化に
伴う酸化反応により酸化触媒９上で排気中のＮＯがＮＯ
2に変化し、これによりパティキュレートの焼却除去に
供される酸化剤（ＮＯ2）が生成され、この酸化剤によ
りパティキュレートを焼却除去する。よって、ＤＰＦ温
度が約５５０℃未満の場合でもＤＰＦ２１の再生が可能
となり、この場合ＤＰＦの強制再生速度は一般には自己
再生速度よりも遅いが、約４００℃のＤＰＦ温度におい
てパティキュレート（スート）の酸化（焼却除去）は可
能である。As a side effect, NO in the exhaust gas on the oxidation catalyst 9 is NO due to the oxidation reaction accompanying the activation of the oxidation catalyst 9.
2 , the oxidant (NO 2 ) used for incineration and removal of particulates is generated, and this oxidant incinerates and removes particulates. Therefore, even when the DPF temperature is lower than about 550 ° C., the DPF 21 can be regenerated. In this case, the forced regeneration speed of the DPF is generally lower than the self-regeneration speed, but at a DPF temperature of about 400 ° C. Oxidation (incineration removal) is possible.
【００５０】強制再生制御の開始条件は、パティキュレ
ート捕集量が許容量を越えていること、機関暖機が完了
していること、機関負荷及び回転速度が所定値以上であ
ること等を含む。つまり、酸化触媒９の酸化反応を利用
してパティキュレートを焼却除去することから、機関冷
態時や低負荷低回転での運転時のように排気温度が低い
ときには、酸化触媒９が活性化しないため、強制再生制
御は行わない。The conditions for starting the forced regeneration control include that the particulate collection amount exceeds the permissible amount, that the engine warm-up is completed, that the engine load and the rotation speed are above a predetermined value. . That is, since the particulates are incinerated and removed by utilizing the oxidation reaction of the oxidation catalyst 9, the oxidation catalyst 9 is not activated when the exhaust gas temperature is low, such as when the engine is cold or when the engine is operated at low load and low speed. Therefore, forced regeneration control is not performed.
【００５１】ＥＣＵ２１は、上流側及び下流側圧力セン
サ１１ａ，１１ｂの検出値Ｐ1,Ｐ2から求めたＤＰＦ１
２の前後差圧ΔＰと、燃料噴射量及びエアフローセンサ
４にて検出された吸入空気量Ａから求めた排ガス流量Ｖ
との関係から、ＤＰＦ１２のパティキュレート捕集量を
推定し、その捕集量が許容量を越え、且つ、エンジン１
の運転状態が上記した暖機完了等の所定条件を満たすと
きに、強制再生制御を開始する。The ECU 21 determines the DPF1 obtained from the detected values P1 and P2 of the upstream and downstream pressure sensors 11a and 11b.
Exhaust gas flow rate V obtained from the front-back differential pressure ΔP of 2 and the fuel injection amount and the intake air amount A detected by the air flow sensor 4.
The estimated amount of particulates collected by the DPF 12 is estimated from the relationship with, and the amount of collected particulates exceeds the allowable amount, and the engine 1
The forced regeneration control is started when the operating condition of (3) satisfies a predetermined condition such as the completion of warm-up described above.
【００５２】一方、パティキュレート捕集量が許容量を
越えたときにも強制再生制御が必ずしも開始されないこ
とから、強制再生制御開始時のパティキュレート捕集量
にはバラツキが生じ、当該捕集量のバラツキは強制再生
時のパティキュレートの燃焼状態に影響を及ぼす。そこ
で、本実施形態の排気浄化装置では、ＤＰＦ温度や排ガ
ス中に含まれる酸素量に加えてパティキュレート捕集量
も考慮した上で、パティキュレートの燃焼状態を制御し
ており、以下、この制御の詳細を説明する。On the other hand, since the forced regeneration control is not always started even when the particulate collection amount exceeds the allowable amount, the particulate collection amount at the start of the forced regeneration control varies, and the collection amount concerned. Variation affects the combustion state of particulates during forced regeneration. Therefore, in the exhaust emission control device of the present embodiment, the combustion state of particulates is controlled in consideration of the particulate matter trapping amount in addition to the DPF temperature and the amount of oxygen contained in the exhaust gas. Will be described in detail.
【００５３】ＥＣＵ２１は図２に示すパティキュレート
燃焼制御ルーチンを所定の制御インターバルで実行し、
まず、ステップＳ２で開始条件が成立したか否かを判定
する。この開始条件は、上記した強制再生制御の開始条
件と同一内容として設定されており、強制再生制御と並
行して当該燃焼制御ルーチンが実行されることになる。The ECU 21 executes the particulate combustion control routine shown in FIG. 2 at a predetermined control interval,
First, in step S2, it is determined whether the start condition is satisfied. This start condition is set as the same content as the start condition of the above-mentioned forced regeneration control, and the combustion control routine is executed in parallel with the forced regeneration control.
【００５４】続くステップＳ４では下流側温度センサ１
０ｂの検出値Ｔ2に基づき、以下の手順でＤＰＦ出口温
度Ｔ2eを推定する（温度推定要素）。つまり、図３は温
度上昇時におけるセンサ検出値Ｔ2とＤＰＦ出口温度Ｔ2
eとの関係を示す説明図であるが、下流側温度センサ１
０ｂの応答遅れの影響により、破線で示す実際のＤＰＦ
出口温度Ｔ2eに対して、検出値Ｔ2は実線で示すように
遅れて増加するため、このセンサの応答遅れによる誤差
を排除する目的でステップＳ４の処理が行われる。In the subsequent step S4, the downstream temperature sensor 1
Based on the detected value T2 of 0b, the DPF outlet temperature T2e is estimated by the following procedure (temperature estimation element). That is, FIG. 3 shows the sensor detection value T2 and the DPF outlet temperature T2 when the temperature rises.
It is explanatory drawing which shows the relationship with e, but the downstream side temperature sensor 1
Due to the response delay of 0b, the actual DPF shown by the broken line
Since the detected value T2 increases with a delay as shown by the solid line with respect to the outlet temperature T2e, the process of step S4 is performed for the purpose of eliminating an error due to the response delay of this sensor.
【００５５】ステップＳ４では、まず、下流側温度セン
サ１０ｂの検出値Ｔ2を所定時間毎にサンプリングし、
下式(1)に従って温度変化量ΔＴ2を算出する。
ΔＴ2＝Ｔ2(n)−Ｔ2(n-m) ………(1)
ここで、Ｔ2(n)は今回のサンプリング値、Ｔ2(n-m)はｍ
回前のサンプリング値である。その後、図４のマップに
従って現在の排ガス流量Ｖ（上記のように燃料噴射量及
び吸入空気量Ａに基づいて算出する）から応答係数Ｋを
求める。このマップ特性は、事前の実験により求められ
たものであり、排ガス流量Ｖの増加に伴って応答係数Ｋ
が減少するように設定される。In step S4, first, the detected value T2 of the downstream temperature sensor 10b is sampled at predetermined intervals,
The temperature change amount ΔT2 is calculated according to the following equation (1). ΔT2 = T2 (n) -T2 (nm) (1) where T2 (n) is the current sampling value and T2 (nm) is m
It is the sampling value of the previous time. Then, the response coefficient K is obtained from the current exhaust gas flow rate V (calculated based on the fuel injection amount and the intake air amount A as described above) according to the map of FIG. This map characteristic is obtained by an experiment in advance, and the response coefficient K increases as the exhaust gas flow rate V increases.
Is set to decrease.
【００５６】そして、得られた検出値Ｔ2、温度変化量
ΔＴ2、応答係数Ｋに基づき、下式(2)に従ってＤＰＦ出
口温度Ｔ2eを算出する。
Ｔ2e＝Ｔ2(n)＋ΔＴ2×Ｋ ………(2)
上記第(2)式は、排ガス流量Ｖが大きいほど、実際ＤＰ
Ｆ出口温度Ｔ2eに対する下流側温度センサ１０ｂの検出
値Ｔ2の追従遅れが小さいことを反映している。Then, the DPF outlet temperature T2e is calculated according to the following equation (2) based on the obtained detected value T2, temperature variation ΔT2, and response coefficient K. T2e = T2 (n) + ΔT2 × K (2) The above equation (2) shows that as the exhaust gas flow rate V increases, the actual DP
This reflects that the follow-up delay of the detected value T2 of the downstream temperature sensor 10b with respect to the F outlet temperature T2e is small.
【００５７】その後、ＥＣＵ２１はステップＳ６に移行
してパティキュレート捕集量を推定する（酸素供給量調
整要素の捕集量推定機能）。この推定処理では、強制再
生制御の開始要件であるパティキュレート捕集量を推定
する場合と同様、ＤＰＦ前後差圧ΔＰと排ガス流量Ｖと
の関係に基づいてＤＰＦ１２のパティキュレート捕集量
が推定される。続くステップＳ８では、ステップＳ６で
推定されたパティキュレート捕集量と判定値とを比較す
ることにより、パティキュレート捕集量が適量か過剰で
あるかを判定する。これは、パティキュレート捕集量に
よってＤＰＦ１２に供給すべき最適酸素量が異なるから
である。After that, the ECU 21 proceeds to step S6 to estimate the particulate collection amount (capture amount estimation function of the oxygen supply amount adjusting element). In this estimation processing, as in the case of estimating the particulate matter trapping amount which is the start requirement of the forced regeneration control, the particulate matter trapping amount of the DPF 12 is estimated based on the relationship between the DPF front-rear differential pressure ΔP and the exhaust gas flow rate V. It In a succeeding step S8, it is determined whether the particulate trap amount is an appropriate amount or an excessive amount by comparing the particulate trap amount estimated in step S6 with the determination value. This is because the optimum amount of oxygen to be supplied to the DPF 12 differs depending on the amount of collected particulates.
【００５８】本実施形態では、パティキュレート捕集量
が適量である場合につき、ＤＰＦ上でパティキュレート
を適切に燃焼させることができる適正燃焼域が、ＤＰＦ
温度の関数として、事前の実験により図５に示すように
設定される。また、パティキュレート捕集量が過剰であ
る場合についての適正燃焼域が実験により図６に示すよ
うに予め設定される。図５および図６中、適正燃焼域内
の太線は最適酸素量を示し、上部ハッチング領域はＤＰ
Ｆ溶損のおそれがあるメルト域を示し、下部ハッチング
領域はＤＰＦ上でパティキュレートを良好に燃焼するこ
とができない不良再生域を示す。当然ながら、図５の適
量時のマップに比較して図６の過剰時のマップでは、同
一ＤＰＦ温度において最適酸素量optＯＸがより小さな
値に設定されて、急激な燃焼が抑制されるように配慮さ
れている。In the present embodiment, when the amount of trapped particulates is appropriate, the proper combustion region where the particulates can be properly burned on the DPF is the DPF.
As a function of temperature, it has been set as shown in Figure 5 by prior experiments. Further, an appropriate combustion region in the case where the amount of collected particulates is excessive is experimentally set in advance as shown in FIG. 5 and 6, the thick line in the proper combustion region shows the optimum oxygen amount, and the upper hatched region is DP.
F indicates a melt region where there is a possibility of F melting loss, and the lower hatched region indicates a defective regeneration region in which particulates cannot be satisfactorily burned on the DPF. As a matter of course, in the excess time map of FIG. 6, as compared with the appropriate time map of FIG. 5, the optimum oxygen amount optOX is set to a smaller value at the same DPF temperature so that rapid combustion is suppressed. Has been done.
【００５９】さて、本パティキュレート燃焼制御ルーチ
ンにおいて、パティキュレート捕集量が適量であるとス
テップＳ８で判定されたときにはステップＳ１０に移行
し、図５の適量時のマップに従って、上記ＤＰＦ出口温
度Ｔ2eを現在のＤＰＦ温度と見なして最適酸素量optＯ
Ｘを求め（酸素供給量調整要素の最適酸素量算出機
能）、その後にステップＳ１４に移行する。又、パティ
キュレート捕集量が過剰なときにはステップＳ１２に移
行し、図６の過剰時のマップに従って最適酸素量optＯ
Ｘを求め、ステップＳ１４に移行する。尚、マップを選
択する代わりに、両マップを補完処理することにより、
パティキュレート捕集量に完全に対応する最適酸素量op
tＯＸを求めるようにしてもよい。Now, in this particulate combustion control routine, when it is determined in step S8 that the particulate collection amount is appropriate, the process proceeds to step S10, and the DPF outlet temperature T2e according to the map for the appropriate amount in FIG. Is regarded as the current DPF temperature and the optimum oxygen amount optO
X is calculated (the optimum oxygen amount calculation function of the oxygen supply amount adjusting element), and then the process proceeds to step S14. Further, when the particulate collection amount is excessive, the process proceeds to step S12, and the optimum oxygen amount optO is calculated according to the excess map of FIG.
X is obtained, and the process proceeds to step S14. In addition, instead of selecting the map, by complementing both maps,
Optimum oxygen amount that perfectly corresponds to the amount of particulate collection op
You may make it calculate tOX.
【００６０】ステップＳ１４では、現在のエンジン１の
運転状態において、弊害を発生させることなく実現可能
な上限酸素量HiＯＸ及び下限酸素量LoＯＸを求める（酸
素供給量調整要素の上限、下限酸素量算出機能）。例え
ば、酸素過剰の運転状態では失火やドライバビリティの
悪化等が顕著となる一方、酸素不足の運転状態ではスモ
ークの発生が顕著となるが、ステップＳ１４では、この
ような弊害を抑制可能な上限及び下限の酸素量HiＯＸ，
LoＯＸを、図示しないマップからエンジン負荷（例え
ば、燃料噴射量）とエンジン回転速度Ｎeとに基づいて
設定する。In step S14, the upper limit oxygen amount HiOX and the lower limit oxygen amount LoOX which can be realized without causing any adverse effect in the present operating state of the engine 1 are obtained (the upper limit and lower limit oxygen amount calculating functions of the oxygen supply amount adjusting element). ). For example, misfire and deterioration of drivability are significant in an operating state with excess oxygen, while smoke is prominent in an operating state with insufficient oxygen. However, in step S14, an upper limit and Lower limit oxygen amount HiOX,
LoOX is set from a map (not shown) based on the engine load (for example, fuel injection amount) and the engine rotation speed Ne.
【００６１】続くステップＳ１６では最適酸素量optＯ
Ｘが上限酸素量HiＯＸを越えているか否かを判定し、Ｙ
ＥＳ（肯定）のときには、ステップＳ１８で目標酸素量
tgtＯＸとして上限酸素量HiＯＸを設定した後、ステッ
プＳ２０で吸気絞り弁７及びＥＧＲ弁１６の開度を制御
して、排ガス中に残存する実際の酸素量を目標酸素量tg
tＯＸにフィードバック制御する。具体的には、新気量
とＥＧＲ量との割合に応じて、筒内に供給される酸素
量、ひいては排ガス中に残存する酸素量が変化すること
から、吸気絞り弁７及びＥＧＲ弁１６の開度を調整する
ことにより酸素量の調整を行う。尚、排ガス中に残存す
る酸素量は、筒内への噴射燃料の全てが燃焼したものと
仮定すると、筒内への酸素供給量から燃料噴射量相当分
の燃焼に要する酸素量を減算して求められ、筒内への酸
素供給量は、新気量とＥＧＲ量とに基づいて算出でき
る。In the following step S16, the optimum oxygen amount optO
It is determined whether X exceeds the upper limit oxygen amount HiOX, and Y
If ES (affirmative), the target oxygen amount is determined in step S18.
After setting the upper limit oxygen amount HiOX as tgtOX, the opening amounts of the intake throttle valve 7 and the EGR valve 16 are controlled in step S20 to determine the actual oxygen amount remaining in the exhaust gas as the target oxygen amount tg.
Feedback control to tOX. Specifically, since the amount of oxygen supplied to the cylinder, and thus the amount of oxygen remaining in the exhaust gas, changes according to the ratio of the fresh air amount and the EGR amount, the intake throttle valve 7 and the EGR valve 16 are The amount of oxygen is adjusted by adjusting the opening. Note that the amount of oxygen remaining in the exhaust gas is calculated by subtracting the amount of oxygen required for combustion corresponding to the fuel injection amount from the amount of oxygen supplied to the cylinder, assuming that all of the fuel injected into the cylinder has burned. The obtained oxygen supply amount into the cylinder can be calculated based on the fresh air amount and the EGR amount.
【００６２】又、前記ステップＳ１６の判定がＮＯ（否
定）のとき、即ち、最適酸素量optＯＸが上限酸素量Hi
ＯＸ以下のときには、ステップＳ２２に移行して最適酸
素量optＯＸが下限酸素量LoＯＸ未満であるか否かを判
定する。判定がＹＥＳのときにはステップＳ２４に移行
して、目標酸素量tgtＯＸとして下限酸素量LoＯＸを設
定した後、前記ステップＳ２０で酸素量のフィードバッ
ク制御を行う。When the determination in step S16 is NO (negative), that is, the optimum oxygen amount optOX is the upper limit oxygen amount Hi.
When it is less than or equal to OX, the process proceeds to step S22, and it is determined whether or not the optimum oxygen amount optOX is less than the lower limit oxygen amount LoOX. When the determination is YES, the process proceeds to step S24, and the lower limit oxygen amount LoOX is set as the target oxygen amount tgtOX, and then the oxygen amount feedback control is performed in step S20.
【００６３】一方、前記ステップＳ２２の判定がＮＯの
とき、即ち、最適酸素量optＯＸが上限酸素量HiＯＸと
下限酸素量LoＯＸとの間にあるときにはステップＳ２６
に移行し、目標酸素量tgtＯＸとして最適酸素量optＯＸ
を設定した後に、前記ステップＳ２０に移行する。On the other hand, when the determination in step S22 is NO, that is, when the optimum oxygen amount optOX is between the upper limit oxygen amount HiOX and the lower limit oxygen amount LoOX, step S26.
And the optimum oxygen amount optOX is set as the target oxygen amount tgtOX.
After setting, shifts to the step S20.
【００６４】以上のように本実施形態の排気浄化装置で
は、パティキュレートの燃焼状態に影響する要因とし
て、排ガス中の酸素量及びＤＰＦ温度に加えてパティキ
ュレート捕集量を考慮し、捕集量に応じて選択したマッ
プに基づいてＤＰＦ２１へ供給される酸素量を調整し
て、強制再生制御時のパティキュレートの燃焼状態を制
御している。その結果、捕集量に関わらずパティキュレ
ートを適切な燃焼状態（図５，図６のマップ中の太線
上）で焼却し、ＤＰＦ１２を溶損させることなく確実に
再生することができる。As described above, in the exhaust gas purification apparatus of this embodiment, the amount of collected particulate matter is taken into consideration in addition to the amount of oxygen in the exhaust gas and the DPF temperature as factors affecting the combustion state of particulate matter. The amount of oxygen supplied to the DPF 21 is adjusted based on the map selected in accordance with the above, and the combustion state of particulates during forced regeneration control is controlled. As a result, the particulates can be incinerated in an appropriate combustion state (on the thick line in the maps of FIGS. 5 and 6) regardless of the trapped amount, and the DPF 12 can be reliably regenerated without melting damage.
【００６５】又、強制再生制御時には、パティキュレー
ト捕集量より選択したマップに従ってＤＰＦ温度から最
適酸素量optＯＸ（即ち、目標酸素量tgtＯＸ）を設定し
て、排ガス中の酸素量をフィードバック制御している。
そして、排ガス中の酸素量は、吸気絞り弁７及びＥＧＲ
弁１６の開度制御に応じて速やかに調整されることか
ら、例えば実公昭５−３６９４号公報に記載の従来技術
のように、ＤＰＦの熱容量の影響を受けるＤＰＦ温度を
制御した場合に比較して、遥かに良好な応答性で制御可
能である。しかも、最適酸素量optＯＸを設定するため
のＤＰＦ温度として、下流側温度センサ１０ｂの検出値
Ｔ2をそのまま用いることなく、センサ時定数を考慮し
たＤＰＦ出口温度Ｔ2eを適用するため、センサの応答遅
れの影響による検出温度誤差も排除される。During the forced regeneration control, the optimum oxygen amount optOX (that is, the target oxygen amount tgtOX) is set from the DPF temperature according to the map selected from the particulate trap amount, and the oxygen amount in the exhaust gas is feedback-controlled. There is.
The amount of oxygen in the exhaust gas depends on the intake throttle valve 7 and EGR.
Since it is adjusted promptly according to the opening control of the valve 16, it is compared with the case where the DPF temperature affected by the heat capacity of the DPF is controlled as in the prior art disclosed in Japanese Utility Model Publication No. 5-3694. Therefore, it can be controlled with much better responsiveness. Moreover, as the DPF temperature for setting the optimum oxygen amount optOX, the DPF outlet temperature T2e in consideration of the sensor time constant is applied without directly using the detection value T2 of the downstream temperature sensor 10b. Detection temperature error due to influence is also eliminated.
【００６６】その結果、以上の酸素量に基づく制御、及
びセンサ応答遅れの影響による検出温度誤差の排除によ
り、例えば制御遅れの影響が顕著となる急加速や減速等
の過渡状態においても、図５，図６のマップから求めた
最適酸素量optＯＸを正確に達成でき、ひいてはマップ
設定に基づく所期のパティキュレートの燃焼状態を確実
に実現することができる。As a result, the control based on the above oxygen amount and the elimination of the detected temperature error due to the influence of the sensor response delay, for example, even in a transient state such as rapid acceleration or deceleration where the influence of the control delay becomes remarkable, FIG. The optimum oxygen amount optOX obtained from the map of FIG. 6 can be accurately achieved, and the desired particulate combustion state based on the map setting can be reliably achieved.
【００６７】更に、マップから求めた最適酸素量optＯ
Ｘが、エンジン１の運転状態から設定された上限酸素量
HiＯＸと下限酸素量LoＯＸとの範囲を越える場合には、
目標酸素量tgtＯＸとして最適酸素量optＯＸを設定する
ことなく、上限酸素量HiＯＸ若しくは下限酸素量LoＯＸ
に制限するようにした。従って、可能な限り適切なパテ
ィキュレートの燃焼状態を保った上で、酸素量の過剰や
不足に起因する種々の弊害を未然に防止して、強制再生
制御時においても円滑なエンジン運転を実現することが
できる。Further, the optimum oxygen amount optO obtained from the map
X is the upper limit oxygen amount set from the operating state of the engine 1.
When exceeding the range of HiOX and the lower limit oxygen amount LoOX,
The upper limit oxygen amount HiOX or the lower limit oxygen amount LoOX is set without setting the optimum oxygen amount optOX as the target oxygen amount tgtOX.
I tried to limit it to. Therefore, while maintaining a combustion state of particulates that is as appropriate as possible, various problems caused by excess or deficiency of oxygen amount are prevented, and smooth engine operation is achieved even during forced regeneration control. be able to.
【００６８】以下、本発明の第２実施形態に係る排気浄
化装置を説明する。第２実施形態の排気浄化装置は、パ
ティキュレート捕集量に応じて選択される適量時または
過剰時のマップに基づきＤＰＦ温度に応じて設定された
最適酸素量になるように酸素供給量を調整する点で上記
第１実施形態のものに共通する。そして、第２実施形態
のものは、フィルタ再生中の機関運転を円滑にすること
を企図して、酸素供給量の調整に際して、エンジン１で
の燃焼が下限、上限空燃比で行われるときの排気中残存
酸素量と最適酸素量との比較結果に応じて機関燃焼状態
を制御する点に特徴がある。An exhaust purification system according to the second embodiment of the present invention will be described below. The exhaust emission control device of the second embodiment adjusts the oxygen supply amount so that the optimum oxygen amount is set according to the DPF temperature on the basis of a map at the time of appropriate amount or excessive time selected according to the trapped amount of particulates. This is common to the first embodiment in that The second embodiment intends to smooth the engine operation during filter regeneration, and when adjusting the oxygen supply amount, exhaust gas when combustion in the engine 1 is performed at the lower limit and upper limit air-fuel ratios. It is characterized in that the engine combustion state is controlled according to the result of comparison between the medium residual oxygen amount and the optimum oxygen amount.
【００６９】上記の概略説明から分かるように、第２実
施形態の排気浄化装置は、主としてパティキュレート燃
焼制御ルーチンでの制御内容を除き、上記第１実施形態
のものと略同様に構成可能であり、第１実施形態のもの
に共通する点については説明を省略する。As can be seen from the above schematic description, the exhaust emission control system of the second embodiment can be constructed in substantially the same manner as that of the first embodiment, except for the control contents mainly in the particulate combustion control routine. Description of points common to those of the first embodiment will be omitted.
【００７０】排気浄化装置は図１に示すように構成可能
であり、ＥＣＵ２１は吸気絞り弁７及びＥＧＲ弁１６と
共に酸素供給量調整要素を構成している。ＥＣＵ２１に
は、ＤＰＦによるパティキュレート捕集量が適量である
場合に用いられるＤＰＦ温度−酸素供給量マップと捕集
量が過剰である場合に用いられるマップが格納されてい
る（図７及び図８を参照）。両マップは、図５及び図６
に示したものにそれぞれ対応している。The exhaust emission control device can be constructed as shown in FIG. 1, and the ECU 21 constitutes an oxygen supply amount adjusting element together with the intake throttle valve 7 and the EGR valve 16. The ECU 21 stores a DPF temperature-oxygen supply amount map used when the particulate trapped amount by the DPF is an appropriate amount and a map used when the trapped amount is excessive (FIGS. 7 and 8). See). Both maps are shown in FIG. 5 and FIG.
It corresponds to each of those shown in.
【００７１】図７及び図８に示す適量時マップおよび過
剰時マップは、縦軸にＤＰＦ温度をとると共に横軸に酸
素供給量をとって、不良再生域、適正再生域（図５及び
図６中の適正燃焼域に対応）およびメルト域を示したも
のであり、適正再生域ではパティキュレートを良好に燃
焼可能であるが、不良再生域ではパティキュレートを良
好に燃焼することができず、また、メルト域ではＤＰＦ
溶損のおそれがある。In the proper amount time map and the excess time map shown in FIGS. 7 and 8, the vertical axis represents the DPF temperature and the horizontal axis represents the oxygen supply amount, and the defective regeneration region and the proper regeneration region (FIGS. 5 and 6) are shown. (Corresponding to the proper combustion area in the middle) and the melt area. The particulates can be satisfactorily burned in the proper regeneration area, but the particulates cannot be satisfactorily burned in the poor regeneration area. , DPF in the melt area
There is a risk of melting.
【００７２】図７及び図８中、記号ＣＣ１及びＣＣ２は
第１、第２再生下限酸素量を示し、換言すれば所定範囲
を有する再生下限酸素量ＣＣを示している。また、記号
ＤＤ１及びＤＤ２は第１、第２再生上限酸素量すなわち
所定範囲を有する再生上限酸素量ＤＤを示す。また、記
号ＳＳ１及びＳＳ２は第１、第２最適酸素量すなわち所
定変範囲を有する最適酸素量ＳＳを表している。この様
に、再生下限酸素量ＣＣ、再生上限酸素量ＤＤおよび最
適酸素量ＳＳのそれぞれを所定範囲を有したものとして
設定することにより、後述のように酸素供給量の調整に
際して機関燃焼状態（例えば空燃比）を可変制御した際
の制御誤差により酸素供給量に応じてＤＰＦ温度が不良
再生域やメルト域に入るおそれが低減する。In FIGS. 7 and 8, symbols CC1 and CC2 indicate the first and second regeneration lower limit oxygen amounts, in other words, the regeneration lower limit oxygen amount CC having a predetermined range. Further, symbols DD1 and DD2 indicate the first and second regeneration upper limit oxygen amounts, that is, the regeneration upper limit oxygen amount DD having a predetermined range. The symbols SS1 and SS2 represent the first and second optimum oxygen amounts, that is, the optimum oxygen amount SS having a predetermined variable range. In this manner, the regeneration lower limit oxygen amount CC, the regeneration upper limit oxygen amount DD, and the optimum oxygen amount SS are each set to have a predetermined range, so that the engine combustion state (for example, when adjusting the oxygen supply amount, as will be described later) The risk of the DPF temperature entering the defective regeneration region or the melt region depending on the oxygen supply amount is reduced due to a control error when the air-fuel ratio) is variably controlled.
【００７３】再生下限酸素量ＣＣ及び再生上限酸素量Ｄ
ＤはＤＰＦ温度に応じてそれぞれ変化し、図７及び図８
中、再生下限酸素量ラインおよび再生上限酸素量ライン
をなしている。再生下限酸素量ラインおよび再生上限酸
素量ラインは、再生可能温度たとえば約２５０℃を表す
再生可能温度ラインと共に適正再生域を画成している。
最適酸素量ＳＳが描く最適酸素量ラインは適正再生域内
にある。図示の如く、最適酸素量は再生下限酸素量ＣＣ
と再生上限酸素量ＤＤとの中間値近傍の値または該中間
値よりも再生下限酸素量側の値に設定され、これにより
酸素不足や酸素過多による弊害が生じるおそれが低減す
るとともに、ＤＰＦ温度がメルト域に達することが確実
に防止される。Regeneration lower limit oxygen amount CC and regeneration upper limit oxygen amount D
D changes according to the DPF temperature.
It has a medium lower limit regeneration line and a higher regeneration limit oxygen line. The regeneration lower limit oxygen amount line and the regeneration upper limit oxygen amount line define a proper regeneration region together with a reproducible temperature line representing a reproducible temperature, for example, about 250 ° C.
The optimum oxygen amount line drawn by the optimum oxygen amount SS is within the proper regeneration range. As shown, the optimum oxygen amount is the lower limit regeneration oxygen amount CC
Is set to a value close to an intermediate value between the regeneration upper limit oxygen amount DD and the regeneration lower limit oxygen amount side with respect to the intermediate value, thereby reducing the risk of adverse effects due to oxygen deficiency or excess oxygen, and increasing the DPF temperature. The melt area is reliably prevented from reaching.
【００７４】既述のように、第２実施形態では、下限、
上限空燃比で運転されるエンジン１から排出される排気
中の第１、第２残存酸素量に基づいてエンジン１におけ
る燃焼状態を制御するようにしている。この様な燃焼制
御に関連して、図９に示すように、酸素供給量調整要素
としてのＥＣＵ２１は、下限空燃比算出部２１ａ、上限
空燃比算出部２１ｂおよび残存酸素量演算部２１ｃを備
えている。As described above, in the second embodiment, the lower limit,
The combustion state in the engine 1 is controlled based on the first and second residual oxygen amounts in the exhaust gas discharged from the engine 1 operated at the upper limit air-fuel ratio. In relation to such combustion control, as shown in FIG. 9, the ECU 21 as an oxygen supply amount adjustment element includes a lower limit air-fuel ratio calculation unit 21a, an upper limit air-fuel ratio calculation unit 21b, and a residual oxygen amount calculation unit 21c. There is.
【００７５】下限空燃比算出部２１ａでは、予め実験的
に求めたＮｅ−Ｑ−Ａ／Ｆminマップを参照して、エン
ジン回転数Nｅと燃料噴射量Ｑとに基づき下限空燃比Ａ
／Ｆminが算出される。このマップにおいて、下限空燃
比は、この下限空燃比以上の空燃比でエンジン１を運転
したときに例えばパティキュレート排出量やドライバビ
リティなどが許容できるものになるような値に設定され
ている。また、上限空燃比算出部２１ｂでは、上限空燃
比Ａ／Ｆmaxが、エンジン回転速度Ｎeと燃料噴射量Ｑと
に基づきNｅ−Ｑ−Ａ／Ｆmaxマップから算出される。上
限空燃比は、この上限空燃比以下の空燃比でエンジン１
を運転したときに例えばＮＯｘ排出量や機関運転騒音が
許容限度以下になるような値に設定されている。図９
中、２つのマップを模式的に示し、その詳細を省略す
る。The lower limit air-fuel ratio calculating section 21a refers to the Ne-Q-A / Fmin map experimentally obtained in advance and refers to the engine speed Ne and the fuel injection amount Q to determine the lower limit air-fuel ratio A.
/ Fmin is calculated. In this map, the lower limit air-fuel ratio is set to a value such that, for example, when the engine 1 is operated at an air-fuel ratio that is equal to or higher than the lower limit air-fuel ratio, the particulate emission amount, drivability, etc. can be allowed. Further, the upper limit air-fuel ratio calculation unit 21b calculates the upper limit air-fuel ratio A / Fmax from the Ne-Q-A / Fmax map based on the engine rotation speed Ne and the fuel injection amount Q. The upper limit air-fuel ratio is an air-fuel ratio below this upper limit air-fuel ratio for the engine 1
When the engine is operated, for example, the NOx emission amount and engine operation noise are set to values below the allowable limit. Figure 9
Medium and two maps are schematically shown and the details thereof are omitted.
【００７６】残存酸素量演算部２１ｃでは、４気筒エン
ジンの場合、エアフローセンサ値（ｇ／sec）を、エン
ジン回転数Ｎeを６０で除したものを２倍した値で除し
て吸入空気量Ａｉ（ｇ／st）が求められ、また、燃料量
Ｑaf（ｇ／st）に理論空燃比１４．５を乗じることによ
り消費空気量Ａｃ（ｇ／st）が求められ、更に、吸入空
気量Ａｉから消費空気量Ａｃを減じることにより残存空
気量Ａｒ（ｇ／st）が求められる。ここで、記号stはス
トロークを表す。そして、１ストロークあたりの残量空
気量Ａｒに対して、エンジン回転数Ｎeを６０で除した
ものに４気筒エンジンに対応する値２と空気中の酸素の
比率０．２３との積を乗じることにより、１秒間あたり
の排気中の残存酸素量（ｇ／sec）が求められる。上記
説明を式で示せば以下のとおりである。In the case of a four-cylinder engine, the remaining oxygen amount calculation unit 21c divides the air flow sensor value (g / sec) by a value obtained by doubling the engine speed Ne divided by 60 to obtain the intake air amount Ai. (G / st) is obtained, and the consumed air amount Ac (g / st) is obtained by multiplying the fuel amount Qaf (g / st) by the theoretical air-fuel ratio 14.5. Further, from the intake air amount Ai The residual air amount Ar (g / st) is obtained by subtracting the consumed air amount Ac. Here, the symbol st represents a stroke. Then, multiplying the remaining air amount Ar per stroke by the engine speed Ne divided by 60 by the product of the value 2 corresponding to a 4-cylinder engine and the ratio of oxygen in air 0.23. Thus, the residual oxygen amount (g / sec) in the exhaust gas per second can be obtained. The above description can be shown by a formula as follows.
【００７７】吸入空気量Ａi(g/st)＝エアフローセンサ
値(g/sec)÷｛（Nｅ／６０）×２｝
消費空気量Ａｃ(g/st)＝Ｑaf×１４．５
残存空気量Ａｒ(g/st)＝Ａｉ−Ａｃ
残存酸素量(g/sec)＝Ａｒ×（Ｎｅ／６０）×２×０．
２３
さて、下限、上限空燃比算出部２１ａ、２１ｂでそれぞ
れ算出された下限、上限空燃比Ａ／Ｆmin、Ａ／Ｆmaxに
よる燃焼時の残存酸素量は、吸入空気量Ａｉを下限、上
限空燃比Ａ／Ｆmin、Ａ／Ｆmaxに燃料量Ｑafを乗じるこ
とにより求める点でのみ相違する。上記説明を式で示せ
ば以下の通りである。Intake air amount Ai (g / st) = air flow sensor value (g / sec) ÷ {(Ne / 60) × 2} Air consumption amount Ac (g / st) = Qaf × 14.5 Residual air amount Ar (g / st) = Ai−Ac Residual oxygen amount (g / sec) = Ar × (Ne / 60) × 2 × 0.
23. The lower limit of the intake air amount Ai and the upper limit air-fuel ratio A of the residual oxygen amount at the time of combustion according to the lower limit and the upper limit air-fuel ratios A / Fmin and A / Fmax calculated by the lower-limit and upper-limit air-fuel ratio calculation units 21a and 21b, respectively The difference is only in that they are obtained by multiplying / Fmin and A / Fmax by the fuel amount Qaf. The above description can be shown by a formula as follows.
【００７８】吸入空気量Ａi(g/st)＝Ａ／Ｆmin（又は、
Ａ／Ｆmax）×Ｑaf
消費空気量Ａｃ(g/st)＝Ｑaf×１４．５
残存空気量Ａｒ(g/st)＝Ａｉ−Ａｃ
残存酸素量(g/sec)＝Ａｒ×（Ｎｅ／６０）×２×０．
２３
下限、上限空燃比燃焼時の残存酸素量と最適酸素量Ｓ
Ｓ、再生下限酸素量ＣＣ、再生上限酸素量ＤＤとの関係
を図１０に例示する。図１０中、記号ＡＡ及び白丸は下
限空燃比燃焼時の残存酸素量（第１残存酸素量）を示
し、記号ＢＢおよび黒丸は上限空燃比燃焼時の残存酸素
量（第２残存酸素量）を示す。Intake air amount Ai (g / st) = A / Fmin (or
A / Fmax) × Qaf Air consumption amount Ac (g / st) = Qaf × 14.5 Residual air amount Ar (g / st) = Ai−Ac Residual oxygen amount (g / sec) = Ar × (Ne / 60) × 2 × 0.
23 Lower and upper limit air-fuel ratio Residual oxygen amount and optimum oxygen amount S during combustion
FIG. 10 illustrates the relationship among S, the lower limit regeneration oxygen amount CC, and the upper limit regeneration oxygen amount DD. In FIG. 10, the symbol AA and the white circles indicate the residual oxygen amount (first residual oxygen amount) at the time of lower limit air-fuel ratio combustion, and the symbol BB and the black circles indicate the residual oxygen amount (second residual oxygen amount) at the time of upper limit air-fuel ratio combustion. Show.
【００７９】以下、図１１及び図１２を参照して、第２
実施形態におけるパティキュレート燃焼制御ルーチンを
説明する。本ルーチンのステップＳ３１（図２のステッ
プＳ６に対応）では、ＤＰＦ前後差圧ΔＰと排ガス流量
Ｖとの関係に基づいてパティキュレート捕集量が推定さ
れ、次のステップＳ３２（図２のステップＳ２に対応）
では、強制再生制御開始条件と同一の燃焼制御開始条件
が成立しているか否かが判定され、これにより再生必要
時期であるか否かが判定される。Hereinafter, referring to FIGS. 11 and 12, the second
The particulate combustion control routine in the embodiment will be described. In step S31 (corresponding to step S6 in FIG. 2) of this routine, the particulate collection amount is estimated based on the relationship between the DPF front-rear differential pressure ΔP and the exhaust gas flow rate V, and the next step S32 (step S2 in FIG. 2). Corresponding to)
Then, it is determined whether or not the same combustion control start condition as the forced regeneration control start condition is satisfied, and thereby, it is determined whether or not the regeneration required time.
【００８０】ステップＳ３２で再生必要時期であること
が判定されると、ＤＰＦ出口温度の推定が行われる（ス
テップＳ３３）。ここでは、図２のステップＳ４の場合
と同様、上記（２）式に従ってＤＰＦ出口温度Ｔ2eが算
出される。If it is determined in step S32 that the regeneration is required, the DPF outlet temperature is estimated (step S33). Here, similar to the case of step S4 of FIG. 2, the DPF outlet temperature T2e is calculated according to the above equation (2).
【００８１】次のステップＳ３４ではＤＰＦ出口温度Ｔ
2eが再生可能温度（例えば約２５０℃）以上であるか否
かが判定され、この判定結果が肯定であればパティキュ
レート捕集量が適量であるか或いは過剰であるかが更に
判定される（ステップＳ３５）。In the next step S34, the DPF outlet temperature T
It is determined whether 2e is equal to or higher than the reproducible temperature (for example, about 250 ° C.), and if the determination result is affirmative, it is further determined whether the particulate collection amount is an appropriate amount or is excessive ( Step S35).
【００８２】そして、パティキュレート捕集量が適量で
あれば、図７に示した適量時のマップを参照して上記Ｄ
ＰＦ出口温度Ｔ2eにより表されるＤＰＦ温度にそれぞれ
対応する最適酸素量ＳＳ、再生下限酸素量ＣＣおよび再
生上限酸素量ＤＤを求める（ステップＳ３６）。また、
捕集量が過剰であれば、図８に示した過剰時のマップを
参照してＤＰＦ温度にそれぞれ対応する最適酸素量Ｓ
Ｓ、再生下限酸素量ＣＣ及び再生上限酸素量ＤＤを求め
る（ステップＳ３７）。If the amount of collected particulates is appropriate, refer to the map for the appropriate amount shown in FIG.
The optimum oxygen amount SS, the regeneration lower limit oxygen amount CC, and the regeneration upper limit oxygen amount DD corresponding to the DPF temperature represented by the PF outlet temperature T2e are obtained (step S36). Also,
If the trapped amount is excessive, refer to the map at the time of excess shown in FIG. 8 to find the optimum oxygen amount S corresponding to each DPF temperature.
S, regeneration lower limit oxygen amount CC and regeneration upper limit oxygen amount DD are obtained (step S37).
【００８３】次のステップＳ３８では、許容可能な機関
運転を行える空燃比の下限値（下限空燃比）が下限空燃
比算出部２１ａにより算出され、次に、下限空燃比で機
関運転を行う場合の残存酸素量すなわち第１残存酸素量
ＡＡが残存酸素量演算部２１ｃにより求められる。更
に、許容可能な機関運転を行える空燃比の上限値（上限
空燃比）が上限空燃比算出部２１ｂにより算出され、次
に、上限空燃比で機関運転を行う場合の排ガス中の残存
酸素量すなわち第２残存酸素量ＢＢが残存酸素量演算部
２１ｃにより求められる。In the next step S38, the lower limit value of the air-fuel ratio (lower limit air-fuel ratio) at which the engine operation is permissible is calculated by the lower limit air-fuel ratio calculating section 21a, and then the engine operation is performed at the lower limit air-fuel ratio. The residual oxygen amount, that is, the first residual oxygen amount AA is calculated by the residual oxygen amount calculation unit 21c. Further, the upper limit value of the air-fuel ratio (upper limit air-fuel ratio) at which the engine operation is permissible is calculated by the upper limit air-fuel ratio calculation unit 21b, and then the residual oxygen amount in the exhaust gas when the engine is operated at the upper limit air-fuel ratio, that is, The second residual oxygen amount BB is calculated by the residual oxygen amount calculation unit 21c.
【００８４】そして、ステップＳ３９では最適酸素量Ｓ
Ｓが第２残存酸素量ＢＢ以下であるか否かが判定され、
この判定結果が肯定（ＳＳ≦ＢＢ）であれば、最適酸素
量ＳＳが第１残存酸素量ＡＡ以上であるか否かが判定さ
れる（ステップＳ４０）。Then, in step S39, the optimum oxygen amount S
It is determined whether S is equal to or less than the second residual oxygen amount BB,
If the determination result is affirmative (SS ≦ BB), it is determined whether or not the optimum oxygen amount SS is equal to or more than the first residual oxygen amount AA (step S40).
【００８５】ステップＳ４０での判定結果が肯定、すな
わち図１０に記号を付して例示したように「ＡＡ≦Ｓ
Ｓ≦ＢＢ」という関係が成立していれば、最適酸素量Ｓ
Ｓを得るように燃焼制御を行う（ステップＳ４１）。こ
の燃焼制御では、例えば、空燃比を許容下限空燃比と許
容上限空燃比との間で可変することにより最適酸素量Ｓ
Ｓを得るべく、最適酸素量ＳＳに対応する空燃比を設定
空燃比として設定し、この設定空燃比になるように吸気
絞り弁７およびＥＧＲ弁１６の開度ならびに燃料噴射ノ
ズル２からの燃料噴射量を制御する。この結果、設定空
燃比での燃焼が行われて最適酸素量ＳＳがＤＰＦ１２に
供給される。すなわち、燃焼制御により酸素供給量が最
適酸素量ＳＳになるように調整される。The determination result in step S40 is affirmative, that is, "AA≤S" as illustrated by adding symbols in FIG.
If the relationship "S≤BB" is established, the optimum oxygen amount S
Combustion control is performed so as to obtain S (step S41). In this combustion control, for example, by changing the air-fuel ratio between the allowable lower limit air-fuel ratio and the allowable upper limit air-fuel ratio, the optimum oxygen amount S
In order to obtain S, the air-fuel ratio corresponding to the optimum oxygen amount SS is set as the set air-fuel ratio, and the opening of the intake throttle valve 7 and the EGR valve 16 and the fuel injection from the fuel injection nozzle 2 are set so as to reach this set air-fuel ratio. Control the amount. As a result, combustion is performed at the set air-fuel ratio, and the optimum oxygen amount SS is supplied to the DPF 12. That is, the oxygen supply amount is adjusted by the combustion control so as to become the optimum oxygen amount SS.
【００８６】一方、ステップＳ４０での判定結果が否定
すなわちＳＳ＜ＡＡ＜ＢＢであれば、第１残存酸素量
（下限空燃比燃焼時の排ガス中残存酸素量）ＡＡが再生
上限酸素量ＤＤ以下であるか否かが更に判別される（ス
テップＳ４２）。そして、ステップＳ４２での判別結果
が肯定すなわち図１０に記号を付して例示したように
「ＳＳ＜ＡＡ≦ＤＤ」なる関係が成立していれば、第１
残存酸素量ＡＡを得るための燃焼制御を行う（ステップ
Ｓ４３）。例えば、設定空燃比を下限空燃比に設定して
下限空燃比で燃焼を行い、ＤＰＦ１２への酸素供給量を
第１残存酸素量ＡＡに調整する。On the other hand, if the determination result in step S40 is negative, that is, SS <AA <BB, the first residual oxygen amount (residual oxygen amount in exhaust gas at the lower limit air-fuel ratio combustion) AA is not more than the regeneration upper limit oxygen amount DD. It is further determined whether or not there is (step S42). Then, if the determination result in step S42 is affirmative, that is, if the relation “SS <AA ≦ DD” is established as illustrated by adding symbols in FIG. 10, the first
Combustion control for obtaining the residual oxygen amount AA is performed (step S43). For example, the set air-fuel ratio is set to the lower limit air-fuel ratio, combustion is performed at the lower limit air-fuel ratio, and the oxygen supply amount to the DPF 12 is adjusted to the first residual oxygen amount AA.
【００８７】また、ステップＳ４２での判別結果が否定
すなわち図１０に記号を付して例示したように「ＡＡ
＞ＤＤおよびＡＡ＞ＳＳ」なる関係が成立していれば、
再生上限酸素量ＤＤを得るための燃焼制御を行う（ステ
ップＳ４４）。例えば、下限空燃比よりも小さい値の設
定空燃比を設定して燃焼を行い、酸素供給量を再生上限
酸素量ＤＤに調整する。Further, the determination result in step S42 is negative, that is, "AA" as shown in FIG.
> DD and AA> SS ”holds,
Combustion control is performed to obtain the regeneration upper limit oxygen amount DD (step S44). For example, a set air-fuel ratio smaller than the lower limit air-fuel ratio is set to perform combustion, and the oxygen supply amount is adjusted to the regeneration upper limit oxygen amount DD.
【００８８】ステップＳ３９での判別結果が否定（ＢＢ
＜ＳＳ）であれば、再生下限酸素量ＣＣが第２残存酸素
量（上限空燃比燃焼時の残存酸素量）ＢＢ以下であるか
否かが判定され（ステップＳ４５）、この判定結果が肯
定すなわち図１０に記号を付して例示したように「Ｃ
Ｃ≦ＢＢ＜ＳＳ」なる関係が成立していれば、第２残存
酸素量ＢＢを得るための燃焼制御を行う（ステップＳ４
６）。例えば、上限空燃比を設定空燃比として設定して
燃焼を行い、酸素供給量を第２残存酸素量ＢＢに調整す
る。一方、ステップＳ４５での判別結果が否定すなわち
図１０に記号を付して例示したように「ＢＢ＜ＣＣお
よびＢＢ＜ＳＳ」なる関係が成立していれば、再生下限
酸素量ＣＣを得るための燃焼制御を行う（ステップＳ４
７）。例えば、上限空燃比よりも大きい値の設定空燃比
を設定して燃焼を行い、酸素供給量を再生下限酸素量Ｃ
Ｃに調整する。The determination result of step S39 is negative (BB
If <SS, it is determined whether or not the regeneration lower limit oxygen amount CC is equal to or less than the second residual oxygen amount (remaining oxygen amount at the time of upper limit air-fuel ratio combustion) BB (step S45), and this determination result is affirmative. As illustrated by adding symbols in FIG. 10, “C
If the relationship of C ≦ BB <SS ”is established, the combustion control for obtaining the second remaining oxygen amount BB is performed (step S4).
6). For example, the upper limit air-fuel ratio is set as the set air-fuel ratio, combustion is performed, and the oxygen supply amount is adjusted to the second residual oxygen amount BB. On the other hand, if the determination result in step S45 is negative, that is, if the relation "BB <CC and BB <SS" is established as illustrated by adding symbols in FIG. 10, the regeneration lower limit oxygen amount CC is obtained. Performs combustion control (step S4)
7). For example, the set air-fuel ratio that is larger than the upper limit air-fuel ratio is set to perform combustion, and the oxygen supply amount is set to the regeneration lower limit oxygen amount C.
Adjust to C.
【００８９】上述の第２実施形態における酸素供給量調
整を要約すれば、最適酸素量ＳＳが第１、第２残存酸素
量ＡＡ、ＢＢ間にあれば最適酸素量ＳＳになるように酸
素供給量が調整され、最適酸素量ＳＳが残存酸素量Ａ
Ａ、ＢＢ間になく且つ第１、第２残存酸素量ＡＡ、ＢＢ
の少なくとも一方が再生下限酸素量ＣＣと再生上限酸素
量ＤＤとの間にあれば第１または第２残存酸素量ＡＡま
たはＢＢのうち最適酸素量ＳＳに近い方になるように酸
素供給量が調整され、また、最適酸素量ＳＳが第１、第
２残存酸素量ＡＡ、ＢＢ間になく且つ第１、第２残存酸
素量ＡＡ、ＢＢが再生下限酸素量、再生上限酸素量Ｃ
Ｃ、ＤＤ間になければ再生下限酸素量ＣＣまたは再生上
限酸素量ＤＤのうち第１、第２残存酸素量ＡＡ、ＢＢに
近い方になるように酸素供給量が調整される。In summary of the adjustment of the oxygen supply amount in the above-described second embodiment, if the optimum oxygen amount SS is between the first and second residual oxygen amounts AA and BB, the oxygen supply amount is adjusted so as to become the optimum oxygen amount SS. Is adjusted, and the optimum oxygen amount SS is the residual oxygen amount A
Not between A and BB and the first and second residual oxygen amounts AA, BB
If at least one of the two is between the regeneration lower limit oxygen amount CC and the regeneration upper limit oxygen amount DD, the oxygen supply amount is adjusted so as to be closer to the optimum oxygen amount SS of the first or second residual oxygen amount AA or BB. The optimum oxygen amount SS is not between the first and second residual oxygen amounts AA and BB, and the first and second residual oxygen amounts AA and BB are the regeneration lower limit oxygen amount and the regeneration upper limit oxygen amount C.
If it is not between C and DD, the oxygen supply amount is adjusted so as to be closer to the first and second residual oxygen amounts AA and BB of the lower limit regeneration oxygen amount CC or the upper limit regeneration oxygen amount DD.
【００９０】この様に、できる限り、下限空燃比ないし
上限空燃比の範囲内の空燃比でエンジン１を円滑に運転
しつつＤＰＦ１２に最適酸素量ＳＳを供給して最適なＤ
ＰＦ再生を行う。最適酸素量ＳＳを供給することによる
最適なＤＰＦ再生が困難であれば、下限空燃比または上
限空燃比での機関運転により最適酸素量ＳＳにより近い
第１または第２残存酸素量ＡＡ、ＢＢをＤＰＦ１２に供
給して円滑な機関運転の下で好適なＤＰＦ再生を行う。
そうでなければ、酸素供給量を再生下限酸素量ＣＣまた
は再生上限酸素量ＤＤに調整してＤＰＦ再生を行う。Thus, as much as possible, the optimum oxygen amount SS is supplied to the DPF 12 while the engine 1 is smoothly operated with the air-fuel ratio within the range of the lower limit air-fuel ratio or the upper limit air-fuel ratio, and the optimum D
Perform PF playback. If the optimum DPF regeneration by supplying the optimum oxygen amount SS is difficult, the first or second residual oxygen amount AA, BB closer to the optimum oxygen amount SS is set to the DPF 12 by operating the engine at the lower limit air-fuel ratio or the upper limit air-fuel ratio. To the DPF to perform suitable DPF regeneration under smooth engine operation.
If not, the oxygen supply amount is adjusted to the regeneration lower limit oxygen amount CC or the regeneration upper limit oxygen amount DD to perform DPF regeneration.
【００９１】結局、第２実施形態の排気浄化装置によれ
ば、ＤＰＦ１２への酸素供給量の適正化と機関運転の円
滑化とを両立させることができる。また、第２実施形態
の排気浄化装置には第１実施形態のものと同様の利点が
ある。例えば、パティキュレート捕集量の大小にかかわ
らず酸素供給量を適正化して、酸素不足や酸素過多に起
因する弊害とくにＤＰＦの溶損を確実に防止することが
できる。After all, according to the exhaust gas purification apparatus of the second embodiment, it is possible to make the supply of oxygen to the DPF 12 appropriate and the engine operation smooth. Further, the exhaust emission control device of the second embodiment has the same advantages as those of the first embodiment. For example, the oxygen supply amount can be optimized regardless of the amount of collected particulates, and the adverse effects caused by oxygen deficiency or excess oxygen, in particular, DPF melting loss can be reliably prevented.
【００９２】以下、本発明の第３実施形態に係る排気浄
化装置を説明する。第３実施形態の排気浄化装置は、パ
ティキュレート捕集量に応じて選択される適量時または
過剰時のマップに基づきＤＰＦ温度に応じて設定された
再生下限酸素量と再生上限酸素量との間の値になるよう
に酸素供給量を調整する点で上記第１、第２実施形態の
ものに共通する。第３実施形態のものは、酸素供給量の
調整に際し、最適燃焼が行われているエンジン１の燃焼
状態に対応する排気中残存酸素量と再生下限酸素量と、
再生上限酸素量との比較結果に応じて燃焼状態を制御す
る点に特徴がある。An exhaust purification system according to the third embodiment of the present invention will be described below. The exhaust emission control device of the third embodiment is arranged between the regeneration lower limit oxygen amount and the regeneration upper limit oxygen amount set according to the DPF temperature on the basis of the map of the proper amount or the excess amount selected according to the particulate collection amount. This is common to the first and second embodiments in that the oxygen supply amount is adjusted so that the value becomes. In the third embodiment, when adjusting the oxygen supply amount, the residual oxygen amount in the exhaust gas and the regeneration lower limit oxygen amount corresponding to the combustion state of the engine 1 in which optimal combustion is performed,
It is characterized in that the combustion state is controlled according to the comparison result with the upper limit oxygen amount for regeneration.
【００９３】上記の概略説明から分かるように、第３実
施形態の排気浄化装置は、主としてパティキュレート燃
焼制御ルーチンでの制御内容を除き、上記第１、第２実
施形態のものと略同様に構成可能であり、第１、第２実
施形態のものに共通する点については説明を省略する。As can be seen from the above schematic description, the exhaust emission control system of the third embodiment is constructed in substantially the same manner as that of the first and second embodiments, except for the control contents mainly in the particulate combustion control routine. This is possible, and description of points common to those of the first and second embodiments will be omitted.
【００９４】排気浄化装置は図１に示すように構成可能
であり、吸気絞り弁７及びＥＧＲ弁１６と共に酸素供給
量調整要素を構成するＥＣＵ２１には、ＤＰＦ１２によ
るパティキュレート捕集量が適量である場合に用いられ
るＤＰＦ温度−酸素供給量マップと捕集量が過剰である
場合に用いられるマップが格納されている。両マップ
は、図１３及び図１４に示すように、最適酸素量ＳＳが
設定されていない点を除き図７及び図８のものと同一で
あり、その説明を省略する。The exhaust gas purification apparatus can be constructed as shown in FIG. 1, and the ECU 21 that constitutes the oxygen supply amount adjusting element together with the intake throttle valve 7 and the EGR valve 16 has an appropriate amount of particulate collection by the DPF 12. The DPF temperature-oxygen supply amount map used in this case and the map used when the trapped amount is excessive are stored. Both maps are the same as those in FIGS. 7 and 8 except that the optimum oxygen amount SS is not set, as shown in FIGS. 13 and 14, and a description thereof will be omitted.
【００９５】既述のように、第３実施形態では、最適燃
焼時の排気中の残存酸素量に基づいて燃焼状態を制御す
るようにしており、これに関連して、図１５に示すよう
に、酸素供給量調整要素としてのＥＣＵ２１は空燃比算
出部２１ｅと残存酸素量演算部２１ｃとを備えている。
空燃比算出部２１ｅでは、予め実験的に求めたＮｅ−Ｑ
−Ａ／Ｆoptマップを参照して、エンジン回転数Ｎｅと
燃料噴射量Ｑとに基づき最適空燃比Ａ／Ｆoptが算出さ
れる。最適空燃比Ａ／Ｆoptはエンジン１で最適な燃焼
が行われるような値に設定されており、ＥＣＵ２１は実
際の空燃比Ａ／Ｆがこの最適空燃比Ａ／Ｆoptとなるよ
うに燃料噴射量や噴射時期を制御したり、吸入空気量や
ＥＧＲ還元量を制御することにより、エンジン１の燃焼
状態が最適なものとなる。図９のものと同様、図１５の
残存酸素量演算部２１ｃでは、最適空燃比Ａ／Ｆoptに
対応して、最適燃焼時における１秒間あたりの排気中の
残存酸素量ＡＡＡが求められる。As described above, in the third embodiment, the combustion state is controlled on the basis of the residual oxygen amount in the exhaust gas at the time of optimum combustion, and in connection with this, as shown in FIG. The ECU 21, which serves as an oxygen supply amount adjusting element, includes an air-fuel ratio calculation unit 21e and a residual oxygen amount calculation unit 21c.
In the air-fuel ratio calculation unit 21e, Ne-Q which is experimentally obtained in advance
With reference to the -A / Fopt map, the optimum air-fuel ratio A / Fopt is calculated based on the engine speed Ne and the fuel injection amount Q. The optimum air-fuel ratio A / Fopt is set to a value at which optimum combustion is performed in the engine 1, and the ECU 21 adjusts the fuel injection amount and the actual air-fuel ratio A / F to the optimum air-fuel ratio A / Fopt. The combustion state of the engine 1 is optimized by controlling the injection timing and the intake air amount and the EGR reduction amount. As in the case of FIG. 9, the residual oxygen amount calculation unit 21c of FIG. 15 obtains the residual oxygen amount AAA in the exhaust gas per second at the time of optimal combustion in accordance with the optimal air-fuel ratio A / Fopt.
【００９６】なお、エンジン１の燃焼状態に対応した残
存酸素量を最適空燃比Ａ／Ｆoptに基づき求める方法以
外に、第２実施形態と同様にエアフローセンサ値、エン
ジン回転数Ｎｅ及び燃料量Ｑafから求めるようにしても
よい。In addition to the method of obtaining the residual oxygen amount corresponding to the combustion state of the engine 1 based on the optimum air-fuel ratio A / Fopt, the air flow sensor value, the engine speed Ne and the fuel amount Qaf are used as in the second embodiment. You may ask.
【００９７】以下、図１６及び図１７を参照して、第３
実施形態におけるパティキュレート燃焼制御ルーチンを
説明する。本ルーチンは、図１１に示したステップＳ３
１〜Ｓ３５にそれぞれ対応するステップＳ５１〜Ｓ５５
を含む。ステップＳ５１ではパティキュレート捕集量が
推定され、ステップＳ５２では再生必要時期であるか否
かが判定され、ステップＳ５３ではＤＰＦ出口温度Ｔ2e
が算出される。そして、ステップＳ５４ではＤＰＦ出口
温度Ｔ2eがＤＰＦ再生可能温度以上であるか否かが判定
され、ステップＳ５５ではパティキュレート捕集量が適
量であるか或いは過剰であるかが判定される。Hereinafter, referring to FIG. 16 and FIG. 17, the third
The particulate combustion control routine in the embodiment will be described. This routine is performed in step S3 shown in FIG.
Steps S51 to S55 corresponding to 1 to S35, respectively
including. In step S51, the amount of collected particulates is estimated, in step S52, it is determined whether or not it is time to regenerate, and in step S53, the DPF outlet temperature T2e.
Is calculated. Then, in step S54, it is determined whether or not the DPF outlet temperature T2e is equal to or higher than the DPF regenerable temperature, and in step S55, it is determined whether the particulate collection amount is an appropriate amount or is excessive.
【００９８】パティキュレート捕集量が適量であること
がステップＳ５５で判定されると、図１３に示した適量
時のマップを参照してＤＰＦ温度（ＤＰＦ出口温度Ｔ2
e）にそれぞれ対応する再生下限酸素量ＣＣおよび再生
上限酸素量ＤＤが求められる（ステップＳ５６）。ま
た、捕集量が過剰であれば、図１４に示した過剰時のマ
ップを参照してＤＰＦ温度にそれぞれ対応する再生下限
酸素量ＣＣ及び再生上限酸素量ＤＤが求められる（ステ
ップＳ５７）。When it is determined in step S55 that the particulate collection amount is an appropriate amount, the DPF temperature (DPF outlet temperature T2
The regeneration lower limit oxygen amount CC and the regeneration upper limit oxygen amount DD respectively corresponding to e) are obtained (step S56). If the trapped amount is excessive, the regeneration lower limit oxygen amount CC and the regeneration upper limit oxygen amount DD respectively corresponding to the DPF temperature are obtained with reference to the excess map shown in FIG. 14 (step S57).
【００９９】次のステップＳ５８では、エンジン１の燃
焼状態に対応した排ガス中の残存酸素量ＡＡＡが、最適
燃焼時の空燃比Ａ／Ｆopt又はエアフローセンサ値、エ
ンジン回転数Ｎｅ及び燃料量Ｑafに基づき残存酸素量演
算部２１ｃにより求められる。In the next step S58, the residual oxygen amount AAA in the exhaust gas corresponding to the combustion state of the engine 1 is determined based on the air-fuel ratio A / Fopt or the air flow sensor value at the time of optimum combustion, the engine speed Ne and the fuel amount Qaf. It is obtained by the residual oxygen amount calculation unit 21c.
【０１００】そして、ステップＳ５９では残存酸素量Ａ
ＡＡが再生上限酸素量ＤＤ以下であるか否かが判定さ
れ、この判定結果が肯定（ＡＡＡ≦ＤＤ）であれば、残
存酸素量ＡＡＡが再生下限酸素量ＣＣ以上であるか否か
が判定される（ステップＳ６０）。Then, in step S59, the residual oxygen amount A
It is determined whether AA is less than or equal to the regeneration upper limit oxygen amount DD, and if this determination result is affirmative (AAA ≦ DD), it is determined whether the remaining oxygen amount AAA is greater than or equal to the regeneration lower limit oxygen amount CC. (Step S60).
【０１０１】ステップＳ６０での判定結果が肯定すなわ
ち「ＣＣ≦ＡＡＡ≦ＤＤ」という関係が成立していれ
ば、最適燃焼を行う場合にも再生下限酸素量ＣＣから再
生上限酸素量ＤＤまでの範囲内に入る酸素量をＤＰＦ１
２に供給可能であり、従ってフィルタ再生を適正に実施
可能であるので、最適燃焼を継続する（ステップＳ６
１）。If the result of the determination in step S60 is affirmative, that is, if the relationship "CC≤AAA≤DD" is satisfied, the optimum value is within the range from the regeneration lower limit oxygen amount CC to the regeneration upper limit oxygen amount DD even when optimal combustion is performed. The amount of oxygen entering DPF1
2 can be supplied, and therefore the filter regeneration can be properly performed, so that optimum combustion is continued (step S6).
1).
【０１０２】一方、ステップＳ６０での判定結果が否定
すなわち残存酸素量ＡＡＡが再生下限酸素量ＣＣ未満で
「ＡＡＡ＜ＣＣ＜ＤＤ」という関係が成立していれば、
ＤＰＦ１２に供給される酸素供給量が再生下限酸素量Ｃ
Ｃとなるようにエンジン１における燃焼状態を制御する
（ステップＳ６２）。すなわち、最適燃焼を行うとＤＰ
Ｆ１２への酸素供給量が不足してフィルタ再生を良好に
行えないおそれがあるので、酸素供給量を再生下限酸素
量ＣＣに調整するために、例えば、最適燃焼に対応する
最適空燃比Ａ／Ｆoptよりも大きい値の空燃比を設定
し、この設定空燃比でエンジン１を運転する。On the other hand, if the determination result in step S60 is negative, that is, the residual oxygen amount AAA is less than the regeneration lower limit oxygen amount CC and the relation "AAA <CC <DD" is established,
The oxygen supply amount supplied to the DPF 12 is the regeneration lower limit oxygen amount C.
The combustion state in the engine 1 is controlled so as to be C (step S62). In other words, when optimal combustion is performed, DP
Since there is a possibility that the amount of oxygen supplied to F12 is insufficient and the filter regeneration cannot be performed well, in order to adjust the oxygen supply amount to the regeneration lower limit oxygen amount CC, for example, the optimum air-fuel ratio A / Fopt corresponding to the optimal combustion. A larger air-fuel ratio is set, and the engine 1 is operated at this set air-fuel ratio.
【０１０３】ステップＳ５９での判定結果が否定すなわ
ち最適燃焼時の残存酸素量ＡＡＡが再生上限酸素量ＤＤ
を上回っていて、「ＣＣ＜ＤＤ＜ＡＡＡ」という関係が
成立していれば、再生上限酸素量ＤＤが供給されるよう
に燃焼状態を制御する（ステップＳ６３）。すなわち、
最適燃焼を行うと酸素供給量が過剰になってフィルタ溶
損などの不具合が生じるおそれがあるので、酸素供給量
を再生上限酸素量ＤＤに調整するために、例えば、最適
空燃比Ａ／Ｆoptよりも小さい空燃比でのエンジン運転
を行う。The determination result in step S59 is negative, that is, the residual oxygen amount AAA during optimum combustion is the regeneration upper limit oxygen amount DD.
And the relationship of “CC <DD <AAA” is established, the combustion state is controlled so that the regeneration upper limit oxygen amount DD is supplied (step S63). That is,
If optimum combustion is performed, the oxygen supply amount may become excessive, and problems such as filter melting loss may occur. Therefore, in order to adjust the oxygen supply amount to the regeneration upper limit oxygen amount DD, for example, the optimum air-fuel ratio A / Fopt is used. Also operates the engine with a small air-fuel ratio.
【０１０４】上述の第３実施形態における燃焼制御（酸
素供給量調整）を要約すれば、エンジン１において最適
燃焼を実施する場合の排気中残存酸素量ＡＡＡが再生下
限酸素量ＣＣから再生上限酸素量ＤＤまでの範囲内に入
っていれば最適燃焼を行って機関運転性能や排気特性の
最適化を図りつつ適正なＤＰＦ再生を実施し、上記残存
酸素量ＡＡＡが再生下限酸素量ＣＣ未満であれば酸素供
給量が再生下限酸素量ＣＣになるような燃焼制御を行
い、また、残存酸素量ＡＡＡが再生上限酸素量ＤＤを上
回れば酸素供給量が再生上限酸素量ＤＤになるような燃
焼制御を行い、これによりＤＰＦ１２を適正に再生す
る。To summarize the combustion control (adjustment of oxygen supply amount) in the above-described third embodiment, the residual oxygen amount AAA in the exhaust gas when the optimal combustion is performed in the engine 1 is from the regeneration lower limit oxygen amount CC to the regeneration upper limit oxygen amount. If it is within the range up to DD, optimal combustion is performed to optimize engine operating performance and exhaust characteristics, and proper DPF regeneration is performed, and if the residual oxygen amount AAA is less than the regeneration lower limit oxygen amount CC. Combustion control is performed such that the oxygen supply amount becomes the regeneration lower limit oxygen amount CC, and if the residual oxygen amount AAA exceeds the regeneration upper limit oxygen amount DD, the oxygen supply amount becomes the regeneration upper limit oxygen amount DD. Thus, the DPF 12 is properly regenerated.
【０１０５】この様に、できる限り最適燃焼を実施して
機関性能を向上させつつフィルタ再生を行う一方、最適
燃焼を実施したときにＤＰＦ１２への酸素供給量が不足
または過剰になる場合には酸素供給量を再生下限酸素量
ＣＣまたは再生上限酸素量ＤＤに調整してＤＰＦ再生を
行う。As described above, while performing the optimum combustion as much as possible to improve the engine performance and performing the filter regeneration, the oxygen supply amount to the DPF 12 becomes insufficient or excessive when the optimum combustion is performed. The DPF regeneration is performed by adjusting the supply amount to the regeneration lower limit oxygen amount CC or the regeneration upper limit oxygen amount DD.
【０１０６】結局、第３実施形態の排気浄化装置によれ
ば、ＤＰＦ１２への酸素供給量の適正化と燃焼状態の最
適化とを両立させることができる。また、第３実施形態
の排気浄化装置には第１、第２実施形態のものと同様の
利点がある。After all, according to the exhaust gas purification apparatus of the third embodiment, it is possible to make both the optimization of the oxygen supply amount to the DPF 12 and the optimization of the combustion state compatible. Further, the exhaust emission control device of the third embodiment has the same advantages as those of the first and second embodiments.
【０１０７】図１８は、第３実施形態の変形例における
酸素供給量調整を示す。この変形例では、第３実施形態
の場合と同様、最適燃焼時の残存酸素量ＡＡＡが再生下
限酸素量ＣＣ未満であればＤＰＦ１２への酸素供給量を
再生下限酸素量ＣＣに調整し、また、残存酸素量ＡＡＡ
が再生上限酸素量ＤＤを上回れば酸素供給量を再生上限
酸素量ＤＤに調整するものであるが、以下を特徴とす
る。FIG. 18 shows adjustment of the oxygen supply amount in the modification of the third embodiment. In this modification, as in the case of the third embodiment, if the residual oxygen amount AAA during optimal combustion is less than the regeneration lower limit oxygen amount CC, the oxygen supply amount to the DPF 12 is adjusted to the regeneration lower limit oxygen amount CC, and Residual oxygen amount AAA
Is to adjust the oxygen supply amount to the regeneration upper limit oxygen amount DD if the regeneration upper limit oxygen amount DD is exceeded, it is characterized by the following.
【０１０８】すなわち、図１８の変形例では、最適燃焼
時の残存酸素量ＡＡＡ（図１８中、×印で示す）が第１
再生下限酸素量ＣＣ１よりも小さいときは、ＤＰＦ１２
への酸素供給量を第１再生下限酸素量ＣＣ１になるよう
に調整する（図１８中、調整後の酸素供給量を黒丸印で
示す）。また、残存酸素量ＡＡＡが、第１再生下限酸素
量ＣＣ１と第２再生下限酸素量ＣＣ２との間すなわち再
生下限酸素量ＣＣの所定範囲内にあるときには酸素量を
第２再生下限酸素量となるように調整する。そして、残
存酸素量ＡＡＡが第１再生上限酸素量ＤＤ１と第２再生
上限酸素量ＤＤ２との間すなわち再生上限酸素量ＤＤの
所定範囲内にあるときはＤＰＦ１２への酸素供給量を第
１再生上限酸素量ＤＤ１になるように調整し、残存酸素
量ＡＡＡが第２再生上限酸素量ＤＤ２よりも大きいとき
には酸素供給量を第２再生上限酸素量ＤＤ２となるよう
に調整する。That is, in the modified example of FIG. 18, the residual oxygen amount AAA (indicated by a cross in FIG. 18) at the time of optimum combustion is the first.
When it is smaller than the lower limit of regeneration oxygen amount CC1, DPF12
The oxygen supply amount to the first regeneration lower limit oxygen amount CC1 is adjusted (in FIG. 18, the adjusted oxygen supply amount is indicated by a black circle). When the residual oxygen amount AAA is between the first regeneration lower limit oxygen amount CC1 and the second regeneration lower limit oxygen amount CC2, that is, within the predetermined range of the regeneration lower limit oxygen amount CC, the oxygen amount becomes the second regeneration lower limit oxygen amount. To adjust. When the residual oxygen amount AAA is between the first regeneration upper limit oxygen amount DD1 and the second regeneration upper limit oxygen amount DD2, that is, within the predetermined range of the regeneration upper limit oxygen amount DD, the oxygen supply amount to the DPF 12 is set to the first regeneration upper limit. The oxygen amount is adjusted to DD1, and when the residual oxygen amount AAA is larger than the second regeneration upper limit oxygen amount DD2, the oxygen supply amount is adjusted to be the second regeneration upper limit oxygen amount DD2.
【０１０９】この様に、図１８の変形例では、ＤＰＦ１
２への酸素供給量に係る調整を最小限に留めて酸素供給
量調整に伴う機関運転状態の変化を抑制し、また、必要
に応じて酸素供給量を第２再生下限酸素量ＣＣ２または
第１再生上限酸素量ＤＤ１に調整することにより酸素供
給量を安全サイドに調整するようにしている。Thus, in the modification of FIG. 18, the DPF1
The change in the engine operating state accompanying the adjustment of the oxygen supply amount is suppressed by minimizing the adjustment related to the oxygen supply amount to the second regeneration limit, and the oxygen supply amount is adjusted to the second regeneration lower limit oxygen amount CC2 or the first regeneration limit as necessary. The oxygen supply amount is adjusted to the safe side by adjusting the regeneration upper limit oxygen amount DD1.
【０１１０】図１９は、図１８に示した変形例において
適正再生域内に最適酸素量ＳＳを設定した場合の酸素供
給量調整を示す。図１９において、最適酸素量ＳＳは、
第１最適酸素量ＳＳ１とこれよりも大きい第２最適酸素
量ＳＳ２との間の所定範囲を有している。そして、エン
ジン１での燃焼状態に対応する排気中残存酸素量ＡＡＡ
（図１９中、×印で表す）が再生下限酸素量ＣＣより大
きく且つ第１最適酸素量ＳＳ１未満であればＤＰＦ１２
への酸素供給量を第１最適酸素量ＳＳ１に調整する一
方、再生上限酸素量ＤＤ未満であり且つ第２最適酸素量
ＳＳ２よりも大きければ酸素供給量を第２最適酸素量Ｓ
Ｓ２に調整する。すなわち、残存酸素量ＡＡＡが再生下
限酸素量ＣＣと再生上限酸素量ＤＤとの間にあり且つ最
適酸素量ＳＳの所定範囲外にあるときは、酸素供給量を
第１、第２最適酸素量ＳＳ１、ＳＳ２のうちの近接した
方になるように調整する。この様に、図１９の変形例で
は、酸素供給量調整を最小限に留めてエンジン運転状態
の変化を抑制するものになっている。FIG. 19 shows the adjustment of the oxygen supply amount when the optimum oxygen amount SS is set within the proper regeneration range in the modification shown in FIG. In FIG. 19, the optimum oxygen amount SS is
It has a predetermined range between the first optimum oxygen amount SS1 and a larger second optimum oxygen amount SS2. Then, the residual oxygen amount in exhaust gas AAA corresponding to the combustion state in the engine 1
If (represented by X in FIG. 19) is greater than the regeneration lower limit oxygen amount CC and less than the first optimum oxygen amount SS1, DPF12
The oxygen supply amount to the first optimum oxygen amount SS1 is adjusted, while the oxygen supply amount is set to the second optimum oxygen amount S if it is less than the regeneration upper limit oxygen amount DD and larger than the second optimum oxygen amount SS2.
Adjust to S2. That is, when the residual oxygen amount AAA is between the regeneration lower limit oxygen amount CC and the regeneration upper limit oxygen amount DD and is outside the predetermined range of the optimum oxygen amount SS, the oxygen supply amount is set to the first and second optimum oxygen amounts SS1. , SS2, whichever is closer, is adjusted. As described above, in the modification of FIG. 19, the adjustment of the oxygen supply amount is kept to a minimum and the change in the engine operating state is suppressed.
【０１１１】以上で本発明の第１ないし第３実施形態お
よび変形例の説明を終えるが、本発明は上記実施形態や
変形例に限定されるものではない。例えば上記第１ない
し第３実施形態では、排気浄化装置をコモンレール式デ
ィーゼルエンジン１用のものとして具体化し、また、強
制再生制御としてポスト噴射を実施したが、エンジンの
形式や強制再生制御の内容等はこれに限ることはなく、
例えば、通常のディーゼルエンジンに適用して、強制再
生制御としてポスト噴射に代えて吸排気絞りと噴射時期
のリタードを実施してもよい。Although the description of the first to third embodiments and modifications of the present invention has been completed, the present invention is not limited to the above-mentioned embodiments and modifications. For example, in the first to third embodiments described above, the exhaust emission control device is embodied as that for the common rail diesel engine 1 and the post injection is performed as the forced regeneration control. However, the engine type, the content of the forced regeneration control, etc. Is not limited to this,
For example, it may be applied to a normal diesel engine, and intake / exhaust throttle and retard of injection timing may be performed instead of post injection as the forced regeneration control.
【０１１２】なお、上記第１ないし第３実施形態では、
酸素供給量の調整を強制再生制御と共に実施したが、こ
れに限ることなく、例えば強制再生制御が実施されずに
ＤＰＦが自己再生する場合においても上記実施形態同様
にＤＰＦへの酸素供給量を調整するようにしてもよい。
この場合においても、ＤＰＦの不良再生や溶損などが防
止されて、ＤＰＦの再生を適正に行うことができる。In the above first to third embodiments,
The adjustment of the oxygen supply amount was performed together with the forced regeneration control, but the present invention is not limited to this, and for example, when the DPF self-regenerates without performing the forced regeneration control, the oxygen supply amount to the DPF is adjusted as in the above embodiment. You may do it.
Even in this case, defective regeneration of the DPF, melting damage, etc. are prevented, and the DPF can be properly regenerated.
【０１１３】又、上記第１ないし第３実施形態では、Ｄ
ＰＦ１２の上流側に酸化触媒９を設けた連続再生式ＤＰ
Ｆとして後処理装置１４を構成したが、例えば酸化触媒
９をＤＰＦ１２と一体化したり、或いは酸化触媒９を備
えない一般的なＤＰＦとして構成したりしてもよい。In the first to third embodiments, D
Continuous regeneration DP in which an oxidation catalyst 9 is provided on the upstream side of the PF 12.
Although the post-treatment device 14 is configured as F, the oxidation catalyst 9 may be integrated with the DPF 12 or may be configured as a general DPF without the oxidation catalyst 9, for example.
【０１１４】更に、上記第１ないし第３実施形態では、
ＤＰＦ温度としてセンサ応答遅れを考慮したＤＰＦ出口
温度Ｔ2eを適用したが、これに代えて、例えば下流側温
度センサ１０ｂの検出値Ｔ2をそのままＤＰＦ温度とし
て用いても良く、更には上流側温度センサ１０ａの検出
値に基づきＤＰＦ温度を求めてもよい。Furthermore, in the first to third embodiments,
Although the DPF outlet temperature T2e considering the sensor response delay is applied as the DPF temperature, instead of this, for example, the detected value T2 of the downstream side temperature sensor 10b may be used as it is as the DPF temperature, and further, the upstream side temperature sensor 10a. The DPF temperature may be obtained based on the detected value of.
【０１１５】また、上記第１実施形態では、目標酸素量
tgtＯＸを上限酸素量HiＯＸと下限酸素量LoＯＸとに制
限したが、これに代えて、マップから求めた最適酸素量
optＯＸを無条件で目標酸素量tgtＯＸとして設定したり
してもよい。In the first embodiment, the target oxygen amount is
Although tgtOX is limited to the upper limit oxygen amount HiOX and the lower limit oxygen amount LoOX, instead of this, the optimum oxygen amount obtained from the map
optOX may be unconditionally set as the target oxygen amount tgtOX.
【０１１６】[0116]
【発明の効果】請求項１に記載の発明によれば、酸素供
給量調整によりフィルタ温度に応じた適正量の酸素をフ
ィルタに供給することができ、これにより、フィルタ温
度の高低と無関係に常に適正量の酸素の存在下で、酸素
不足や酸素過多による弊害（スモークや失火の発生、フ
ィルタの溶損など）を防止して、フィルタを再生するこ
とができる。According to the invention described in claim 1, an appropriate amount of oxygen according to the filter temperature can be supplied to the filter by adjusting the oxygen supply amount, whereby the filter temperature is always maintained regardless of the height of the filter temperature. In the presence of an appropriate amount of oxygen, the filter can be regenerated by preventing harmful effects (smoke, misfire, filter erosion, etc.) due to lack of oxygen or excess oxygen.
【０１１７】請求項２に記載の発明では、燃焼状態に応
じて変化する排気中の残存酸素量を勘案してフィルタへ
の酸素量を調整するので、酸素供給量をより適正に調整
することができる。According to the second aspect of the present invention, the oxygen amount to the filter is adjusted in consideration of the residual oxygen amount in the exhaust gas which changes according to the combustion state. Therefore, the oxygen supply amount can be adjusted more appropriately. it can.
【０１１８】請求項３に記載の発明によれば、フィルタ
への酸素供給量を最適化することができ、酸素不足や酸
素過多による弊害をより確実に防止しつつ、フィルタの
再生をより良好に実施することができる。According to the third aspect of the present invention, the amount of oxygen supplied to the filter can be optimized, and the adverse effects of oxygen deficiency and excess oxygen can be prevented more reliably while the filter regeneration is improved. It can be carried out.
【０１１９】請求項４に記載の発明では、酸素不足や酸
素過多による弊害、特に酸素過多によるフィルタの溶損
が生じるおそれを解消し又は大幅に低減することができ
る。請求項５に記載の発明では、フィルタへの酸素供給
量を最適化してフィルタの再生を良好に行える。また、
酸素供給量の調整を必要最小限に留めて、フィルタ再生
に伴う機関運転状態の変化を低減し、円滑な機関運転を
阻害するおそれを解消し或いは大幅に低減することがで
きる。According to the fourth aspect of the present invention, it is possible to eliminate or significantly reduce the harmful effects of oxygen deficiency or excess oxygen, and in particular, the risk of melt loss of the filter due to excess oxygen. According to the invention described in claim 5, the regeneration of the filter can be favorably performed by optimizing the oxygen supply amount to the filter. Also,
It is possible to minimize the adjustment of the oxygen supply amount, reduce the change in the engine operating state due to filter regeneration, and eliminate or significantly reduce the possibility of disturbing smooth engine operation.
【０１２０】請求項６に記載の発明によれば、フィルタ
の再生に際して、必要最小限の酸素供給量の調整を行う
ことによりフィルタへの酸素供給量を最適酸素量に近づ
けることができ、また、フィルタ再生中、下限空燃比以
上かつ上限空燃比以下の空燃比で内燃機関を円滑に運転
することができる。According to the sixth aspect of the present invention, when the filter is regenerated, the oxygen supply amount to the filter can be brought close to the optimum oxygen amount by adjusting the necessary minimum oxygen supply amount. During the filter regeneration, the internal combustion engine can be smoothly operated with an air-fuel ratio that is equal to or higher than the lower limit air-fuel ratio and equal to or lower than the upper limit air-fuel ratio.
【０１２１】請求項７に記載の発明では、最適酸素量を
得るように機関運転状態を変化させて（例えば下限空燃
比と上限空燃比との間で空燃比を可変して）フィルタへ
の酸素供給量を最適化して最適なフィルタ再生を行え
る。In the invention described in claim 7, the engine operating state is changed so as to obtain the optimum amount of oxygen (for example, the air-fuel ratio is varied between the lower limit air-fuel ratio and the upper limit air-fuel ratio), and oxygen is supplied to the filter. Optimum supply amount enables optimum filter regeneration.
【０１２２】請求項８に記載の発明では、第１または第
２残存酸素量を得るように機関運転状態を変化させて
（例えば下限空燃比または上限空燃比で内燃機関を運転
して）機関運転の円滑さを損なうことなしにフィルタ再
生を行える。In the invention described in claim 8, the engine is operated by changing the engine operating state so as to obtain the first or second residual oxygen amount (for example, operating the internal combustion engine at the lower limit air-fuel ratio or the upper limit air-fuel ratio). Filter regeneration can be performed without impairing the smoothness of
【０１２３】請求項９に記載の発明では、再生下限酸素
量または再生上限酸素量を得るように機関運転状態を変
化させて（例えば空燃比を調整して）フィルタ再生を行
うことができる。According to the ninth aspect of the invention, the filter regeneration can be performed by changing the engine operating condition (for example, adjusting the air-fuel ratio) so as to obtain the regeneration lower limit oxygen amount or the regeneration upper limit oxygen amount.
【０１２４】請求項１０に記載の発明によれば、燃焼状
態に対応する排気中の残存酸素量を勘案して酸素供給量
が求めることにより適正な酸素供給量を得ると共に酸素
供給量の調整を適正に行うことができる。また、酸素供
給量が再生下限酸素量または再生上限酸素量の所定範囲
内に入るか否かに応じて第１または第２再生下限酸素量
あるいは第１または第２再生上限酸素量になるように酸
素供給量を調整するので、酸素供給量の調整を最小限に
抑制することができ、フィルタ再生に伴う機関運転状態
の変化を最小限に抑制することができる。According to the tenth aspect of the present invention, the oxygen supply amount is determined in consideration of the residual oxygen amount in the exhaust gas corresponding to the combustion state to obtain an appropriate oxygen supply amount and to adjust the oxygen supply amount. It can be done properly. Also, depending on whether or not the oxygen supply amount falls within a predetermined range of the lower limit of regeneration oxygen amount or the upper limit of regeneration oxygen amount, the first or second lower limit of regeneration oxygen amount or the first or second upper limit of regeneration oxygen amount is set. Since the oxygen supply amount is adjusted, the adjustment of the oxygen supply amount can be suppressed to the minimum, and the change in the engine operating state due to the filter regeneration can be suppressed to the minimum.
【０１２５】請求項１１に記載の発明によれば、フィル
タ温度の高低やパティキュレート捕集量の大小と無関係
に常に適正量の酸素の存在下で酸素不足や酸素過多によ
る弊害を回避しつつフィルタを再生することができる。
特に、過度の酸素供給に起因するフィルタ溶損を確実に
防止することができる。According to the eleventh aspect of the present invention, the filter is prevented from being adversely affected by lack of oxygen or excess oxygen in the presence of an appropriate amount of oxygen at all times regardless of the temperature of the filter and the amount of collected particulates. Can be played.
In particular, it is possible to surely prevent the filter melting loss due to excessive oxygen supply.
【０１２６】請求項１２に記載の発明によれば、適正量
の酸素の存在下でもフィルタを十分に再生できないおそ
れがある場合にフィルタ再生を不実施とする結果、推定
パティキュレート捕集量が所定量を上回ってもフィルタ
再生が行われないことがあるが、その後、内燃機関が所
定運転状態になると、推定パティキュレート捕集量に適
した量の酸素の存在下で、酸素不足や酸素過多による弊
害を回避しつつフィルタを再生することができる。According to the twelfth aspect of the present invention, when the filter may not be sufficiently regenerated even in the presence of an appropriate amount of oxygen, the filter regeneration is discontinued, and as a result, the estimated particulate collection amount is reduced. Although the filter regeneration may not be performed even if the amount exceeds the fixed amount, when the internal combustion engine enters the predetermined operating state after that, in the presence of an amount of oxygen suitable for the estimated particulate collection amount, due to lack of oxygen or excess oxygen. The filter can be regenerated while avoiding harmful effects.
【０１２７】請求項１３に記載の発明では、フィルタ又
はフィルタ近傍の温度を検出する温度検出手段の検出出
力とその変化とに基づいて推定したフィルタ温度を酸素
供給量の調整に適用するので、温度検出手段の応答遅れ
の影響による検出温度誤差を除去することができる。In the thirteenth aspect of the invention, the filter temperature estimated based on the detected output of the temperature detecting means for detecting the temperature of the filter or the vicinity of the filter and its change is applied to the adjustment of the oxygen supply amount. It is possible to eliminate the detection temperature error due to the influence of the response delay of the detection means.
【０１２８】請求項１４に記載の発明によれば、酸化触
媒の酸化反応を利用することにより、例えば酸化触媒の
酸化反応による発熱により排気温度を昇温してフィルタ
温度を高めたり、酸化触媒が排気中の成分を酸化させて
生成される酸化剤をフィルタに供給することができ、良
好なフィルタ再生を実施することができる。According to the fourteenth aspect of the present invention, by utilizing the oxidation reaction of the oxidation catalyst, the exhaust gas temperature is raised to raise the filter temperature by the heat generated by the oxidation reaction of the oxidation catalyst, or the oxidation catalyst is The oxidant produced by oxidizing the components in the exhaust gas can be supplied to the filter, and good filter regeneration can be performed.
【図１】本発明の第１実施形態の排気浄化装置を示す全
体構成図である。FIG. 1 is an overall configuration diagram showing an exhaust emission control device of a first embodiment of the present invention.
【図２】図１に示したＥＣＵが実行するパティキュレー
ト燃焼制御ルーチンを示すフローチャートである。FIG. 2 is a flowchart showing a particulate combustion control routine executed by the ECU shown in FIG.
【図３】温度上昇時におけるセンサ検出値Ｔ2とＤＰＦ
出口温度Ｔ2eとの関係を示す説明図である。[Fig. 3] Sensor detection value T2 and DPF when temperature rises
It is explanatory drawing which shows the relationship with outlet temperature T2e.
【図４】排ガス流量Ｖから応答係数Ｋを求めるためのマ
ップを示す説明図である。FIG. 4 is an explanatory diagram showing a map for obtaining a response coefficient K from an exhaust gas flow rate V.
【図５】パティキュレート捕集量が適量なときの最適酸
素量を設定するためのマップを示す説明図である。FIG. 5 is an explanatory diagram showing a map for setting an optimum oxygen amount when the particulate collection amount is an appropriate amount.
【図６】捕集量が過剰なときの最適酸素量を設定するた
めのマップを示す説明図である。FIG. 6 is an explanatory diagram showing a map for setting an optimum oxygen amount when the trapped amount is excessive.
【図７】本発明の第２実施形態に係る排気浄化装置での
パティキュレート燃焼制御においてパティキュレート捕
集量が適量である場合に用いられるＤＰＦ温度−酸素供
給量マップを示す図である。FIG. 7 is a diagram showing a DPF temperature-oxygen supply amount map used when the particulate collection amount is an appropriate amount in the particulate combustion control in the exhaust emission control device according to the second embodiment of the present invention.
【図８】パティキュレート捕集量が過剰である場合に用
いられるマップを示す図である。FIG. 8 is a diagram showing a map used when the amount of collected particulates is excessive.
【図９】酸素供給量調整要素としてのＥＣＵが備える空
燃比算出部および残存酸素量演算部を示す概略ブロック
図である。FIG. 9 is a schematic block diagram showing an air-fuel ratio calculation unit and a residual oxygen amount calculation unit included in the ECU as an oxygen supply amount adjustment element.
【図１０】下限、上限空燃比燃焼時の残存酸素量ＡＡ、
ＢＢと最適酸素量ＳＳ，再生下限酸素量ＣＣ、再生上限
酸素量ＤＤとの関係を例示した図である。FIG. 10 shows a residual oxygen amount AA at the time of combustion of lower and upper limit air-fuel ratios,
It is the figure which illustrated the relationship between BB and optimal oxygen amount SS, regeneration minimum oxygen amount CC, and regeneration maximum oxygen amount DD.
【図１１】第２実施形態に係るパティキュレート燃焼制
御ルーチンの一部を示すフローチャートである。FIG. 11 is a flowchart showing a part of a particulate combustion control routine according to the second embodiment.
【図１２】同制御ルーチンの残部を示すフローチャート
である。FIG. 12 is a flowchart showing the rest of the control routine.
【図１３】本発明の第３実施形態による排気浄化装置で
のパティキュレート燃焼制御においてパティキュレート
捕集量が適量である場合に用いられるＤＰＦ温度−酸素
供給量マップを示す図である。FIG. 13 is a diagram showing a DPF temperature-oxygen supply amount map used when the amount of collected particulates is an appropriate amount in the particulate combustion control in the exhaust purification system according to the third embodiment of the present invention.
【図１４】捕集量が過剰である場合に用いられるマップ
を示す図である。FIG. 14 is a diagram showing a map used when the collection amount is excessive.
【図１５】酸素供給量調整要素としてのＥＣＵが備える
空燃比算出部および残存酸素量演算部を示す概略ブロッ
ク図である。FIG. 15 is a schematic block diagram showing an air-fuel ratio calculation unit and a residual oxygen amount calculation unit included in the ECU as an oxygen supply amount adjustment element.
【図１６】第３実施形態に係るパティキュレート燃焼制
御ルーチンの一部を示すフローチャートである。FIG. 16 is a flowchart showing a part of a particulate combustion control routine according to the third embodiment.
【図１７】同制御ルーチンの残部を示すフローチャート
である。FIG. 17 is a flowchart showing the rest of the control routine.
【図１８】第３実施形態の変形例における酸素供給量調
整を説明する図である。FIG. 18 is a diagram illustrating adjustment of the oxygen supply amount in the modification of the third embodiment.
【図１９】更なる変形例における酸素供給量調整を説明
する図である。FIG. 19 is a diagram illustrating oxygen supply amount adjustment in a further modification.
１ エンジン（内燃機関） ７ 吸気絞り弁 ９ 酸化触媒 １０ｂ 下流側温度センサ １２ ＤＰＦ（フィルタ） １６ ＥＧＲ弁 ２１ ＥＣＵ 1 engine (internal combustion engine) 7 Intake throttle valve 9 Oxidation catalyst 10b Downstream temperature sensor 12 DPF (filter) 16 EGR valve 21 ECU
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） Ｆ０２Ｄ 21/08 ３０１ Ｆ０２Ｄ 21/08 ３０１Ｂ ３０１Ｄ 41/38 41/38 Ｂ // Ｂ０１Ｄ 46/42 Ｂ０１Ｄ 46/42 Ｂ Ｆターム(参考） 3G090 AA01 BA01 CA03 CB18 DA09 DA12 DA13 EA02 EA06 EA07 3G091 AA10 AA11 AA18 AB02 AB13 BA04 BA08 BA17 CA26 CB02 CB07 DC01 EA03 EA07 EA14 EA16 EA17 EA19 FB01 FC04 FC09 HA15 HB05 HB06 3G092 AA02 AA17 AA18 AB03 BA07 BB03 DC01 DC09 DC12 EA01 EA02 EC01 FA18 HD01 HD08 HD09 HE01 HE03 HE08 3G301 HA02 HA11 HA13 JA24 JA32 JB09 LA01 LB11 MA01 MA11 MA18 MA27 ND02 NE01 NE06 PA11 PA16 PD11 PD14 PE01 PE03 4D058 JA32 JB06 MA44 MA51 SA08─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. 7 Identification code FI theme code (reference) F02D 21/08 301 F02D 21/08 301B 301D 41/38 41/38 B // B01D 46/42 B01D 46 / 42 B F term (reference) 3G090 AA01 BA01 CA03 CB18 DA09 DA12 DA13 EA02 EA06 EA07 3G091 AA10 AA11 AA18 AB02 AB13 BA04 BA08 BA17 CA26 CB02 CB07 DC01 EA03 EA07 EA14 EA16 EA17 EA19 FB01 FC04 FC09 HA15 HB05 HB06 3G092 AA02 AA17 AA18 AB03 BA07 BB03 DC01 DC09 DC12 EA01 EA02 EC01 FA18 HD01 HD08 HD09 HE01 HE03 HE08 3G301 HA02 HA11 HA13 JA24 JA32 JB09 LA01 LB11 MA01 MA11 MA18 MA27 ND02 NE01 NE06 PA11 PA16 PD11 PD14 PE01 PE03 4D058 JA32 JB06 MA44 MA51 SA08
Claims (14)
のパティキュレートを捕集するフィルタと該フィルタへ
の酸素供給量を調整可能な酸素供給量調整要素とを有す
る排気浄化装置において、 上記フィルタ又はフィルタ近傍の温度を検出又は推定す
る温度推定要素を備え、 上記酸素供給量調整要素は、上記酸素供給量を、上記フ
ィルタ温度に応じて定められた再生下限酸素量と再生上
限酸素量との間の値となるように調整することを特徴と
する排気浄化装置。1. An exhaust gas purification device comprising a filter provided in an exhaust passage of an internal combustion engine for collecting particulates in exhaust gas, and an oxygen supply amount adjusting element capable of adjusting an oxygen supply amount to the filter, A filter or a temperature estimation element for detecting or estimating the temperature in the vicinity of the filter is provided, and the oxygen supply amount adjustment element is a regeneration lower limit oxygen amount and a regeneration upper limit oxygen amount determined according to the filter temperature. An exhaust emission control device, characterized in that it is adjusted to a value between.
給量を上記内燃機関の燃焼状態に対応する排気中の残存
酸素量から求めることを特徴とする請求項１に記載の排
気浄化装置。2. The exhaust gas purification apparatus according to claim 1, wherein the oxygen supply amount adjusting element obtains the oxygen supply amount from the residual oxygen amount in the exhaust gas corresponding to the combustion state of the internal combustion engine.
限酸素量と上記再生上限酸素量との間で上記フィルタ温
度に応じて最適酸素量を求め、上記酸素供給量を該最適
酸素量となるように又は該最適酸素量に近づくように調
整することを特徴とする請求項１に記載の排気浄化装
置。3. The oxygen supply amount adjusting element obtains an optimum oxygen amount between the regeneration lower limit oxygen amount and the regeneration upper limit oxygen amount according to the filter temperature, and sets the oxygen supply amount to the optimum oxygen amount. The exhaust gas purification device according to claim 1, wherein the exhaust gas purification device is adjusted so as to be close to or close to the optimum oxygen amount.
と上記再生上限酸素量との中間値近傍の値又は該中間値
よりも上記再生下限酸素量側の値に設定されることを特
徴とする請求項３に記載の排気浄化装置。4. The optimum oxygen amount is set to a value in the vicinity of an intermediate value between the regeneration lower limit oxygen amount and the regeneration upper limit oxygen amount or to a value closer to the regeneration lower limit oxygen amount side than the intermediate value. The exhaust emission control device according to claim 3.
よりも大きい第２最適酸素量との間の所定範囲を有し、 上記酸素供給量調整要素は、上記内燃機関の燃焼状態に
対応する排気中の残存酸素量に応じて上記酸素供給量を
求め、該酸素供給量が上記最適酸素量の上記所定範囲外
にあるときには該酸素供給量を上記第１最適酸素量と上
記第２最適酸素量のうちの近接した方になるように調整
することを特徴とする請求項３に記載の排気浄化装置。5. The optimum oxygen amount has a predetermined range between a first optimum oxygen amount and a second optimum oxygen amount which is larger than the first optimum oxygen amount, and the oxygen supply amount adjusting element controls the combustion state of the internal combustion engine. The oxygen supply amount is obtained according to the corresponding residual oxygen amount in the exhaust gas, and when the oxygen supply amount is outside the predetermined range of the optimum oxygen amount, the oxygen supply amount is set to the first optimum oxygen amount and the second optimum oxygen amount. The exhaust gas purification device according to claim 3, wherein the exhaust gas purification device is adjusted so as to be closer to the optimum oxygen amount.
関が下限空燃比及び上限空燃比で運転される際のそれぞ
れの燃焼状態に対応する排気中の第１及び第２残存酸素
量を求め、上記最適酸素量と該第１，第２残存酸素量と
を比較し、この比較結果に応じて上記酸素供給量を調整
することを特徴とする請求項３に記載の排気浄化装置。6. The oxygen supply amount adjusting element obtains first and second residual oxygen amounts in exhaust gas corresponding to respective combustion states when the internal combustion engine is operated at a lower limit air-fuel ratio and an upper limit air-fuel ratio. The exhaust gas purification apparatus according to claim 3, wherein the optimum oxygen amount is compared with the first and second residual oxygen amounts, and the oxygen supply amount is adjusted according to the comparison result.
素量が上記第１残存酸素量と上記第２残存酸素量との間
にある場合には上記酸素供給量を上記最適酸素量となる
ように調整することを特徴とする請求項６に記載の排気
浄化装置。7. The oxygen supply amount adjusting element sets the oxygen supply amount to the optimum oxygen amount when the optimum oxygen amount is between the first residual oxygen amount and the second residual oxygen amount. The exhaust emission control device according to claim 6, wherein the exhaust emission control device is adjusted as follows.
素量が上記第１残存酸素量と上記第２残存酸素量との間
にない場合には上記酸素供給量を上記第１残存酸素量と
上記第２残存酸素量のうち上記最適酸素量に近い方にな
るように調整することを特徴とする請求項６に記載の排
気浄化装置。8. The oxygen supply amount adjusting element adjusts the oxygen supply amount to the first residual oxygen amount when the optimum oxygen amount is not between the first residual oxygen amount and the second residual oxygen amount. 7. The exhaust emission control device according to claim 6, wherein the exhaust gas purifying apparatus is adjusted so as to be closer to the optimum oxygen amount of the second residual oxygen amount.
素量が上記第１残存酸素量と上記第２残存酸素量との間
になく且つ上記第１残存酸素量と上記第２残存酸素量が
上記再生下限酸素量と上記再生上限酸素量との間にない
場合には上記酸素供給量を上記再生下限酸素量と上記再
生上限酸素量のうち上記第１残存酸素量または上記第２
残存酸素量に近い方になるように調整することを特徴と
する請求項６に記載の排気浄化装置。9. The oxygen supply amount adjusting element is characterized in that the optimum oxygen amount is not between the first residual oxygen amount and the second residual oxygen amount, and the first residual oxygen amount and the second residual oxygen amount. Is not between the regeneration lower limit oxygen amount and the regeneration upper limit oxygen amount, the oxygen supply amount is set to the first residual oxygen amount or the second remaining oxygen amount out of the regeneration lower limit oxygen amount and the regeneration upper limit oxygen amount.
The exhaust gas purification device according to claim 6, wherein the exhaust gas purification device is adjusted to be closer to the residual oxygen amount.
酸素量とこれよりも大きい第２再生下限酸素量との間の
所定範囲を有し、 上記再生上限酸素量は、第１再生上限酸素量とこれより
も大きい第２再生上限酸素量との間の所定範囲を有し、 上記酸素供給量調整要素は、上記内燃機関の燃焼状態に
対応する排気中の残存酸素量から上記酸素供給量を求
め、該酸素供給量が上記第１再生下限酸素量よりも小さ
いときには上記酸素供給量を上記第１再生下限酸素量と
なるように調整し、上記酸素供給量が上記再生下限酸素
量の上記所定範囲内にあるときには該酸素供給量を上記
第２再生下限酸素量となるように調整し、上記酸素供給
量が上記再生上限酸素量の上記所定範囲内にあるときに
は該酸素供給量を上記第１再生上限酸素量となるように
調整し、上記酸素供給量が上記第２再生上限酸素量より
も大きいときには該酸素供給量を上記第２再生上限酸素
量となるように調整することを特徴とする請求項１に記
載の排気浄化装置。10. The regeneration lower limit oxygen amount has a predetermined range between a first regeneration lower limit oxygen amount and a second regeneration lower limit oxygen amount which is larger than the first regeneration lower limit oxygen amount, and the regeneration upper limit oxygen amount is the first regeneration upper limit. The oxygen supply amount adjusting element has a predetermined range between an oxygen amount and a second regeneration upper limit oxygen amount that is larger than the oxygen amount, and the oxygen supply amount adjusting element supplies the oxygen from the residual oxygen amount in the exhaust gas corresponding to the combustion state of the internal combustion engine. When the oxygen supply amount is smaller than the first regeneration lower limit oxygen amount, the oxygen supply amount is adjusted to be the first regeneration lower limit oxygen amount, and the oxygen supply amount is equal to the regeneration lower limit oxygen amount. When the oxygen supply amount is within the predetermined range, the oxygen supply amount is adjusted to the second regeneration lower limit oxygen amount, and when the oxygen supply amount is within the predetermined range of the regeneration upper limit oxygen amount, the oxygen supply amount is adjusted to Adjust so that the first regeneration upper limit oxygen amount is reached. The exhaust emission control device according to claim 1, wherein when the oxygen supply amount is larger than the second regeneration upper limit oxygen amount, the oxygen supply amount is adjusted to be the second regeneration upper limit oxygen amount. .
ルタによるパティキュレート捕集量を推定し、この推定
されたパティキュレート捕集量と上記フィルタ温度とに
応じて上記再生下限酸素量および上記再生上限酸素量を
設定することを特徴とする請求項１に記載の排気浄化装
置。11. The oxygen supply amount adjusting element estimates the particulate collection amount by the filter, and the regeneration lower limit oxygen amount and the regeneration are determined according to the estimated particulate collection amount and the filter temperature. The exhaust emission control device according to claim 1, wherein an upper limit oxygen amount is set.
されたパティキュレート捕集量が所定量以上で且つ上記
内燃機関が所定運転状態であるときに、上記酸素供給量
を調整することを特徴とする請求項１に記載の排気浄化
装置。12. The oxygen supply amount adjusting element adjusts the oxygen supply amount when the estimated amount of trapped particulates is a predetermined amount or more and the internal combustion engine is in a predetermined operating state. The exhaust emission control device according to claim 1.
はフィルタ近傍の温度を検出する温度検出要素の検出出
力と該検出出力の変化とに基づいて上記フィルタ又はフ
ィルタ近傍の温度を推定することを特徴とする請求項１
に記載の排気浄化装置。13. The temperature estimating element estimates the temperature of the filter or the vicinity of the filter based on a detection output of a temperature detecting element that detects the temperature of the filter or the vicinity of the filter and a change in the detection output. Claim 1
The exhaust emission control device according to.
上記フィルタよりも上流の上記排気通路に配設される酸
化触媒の酸化反応を利用して再生可能とされることを特
徴とする請求項１に記載の排気浄化装置。14. The filter according to claim 1, wherein the filter can be regenerated by utilizing an oxidation reaction of an oxidation catalyst arranged in the exhaust passage in the filter or upstream of the filter. Exhaust gas purification device described.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002213573A JP2003129835A (en) | 2001-07-26 | 2002-07-23 | Exhaust emission control device |
| KR1020020044078A KR20030010542A (en) | 2001-07-26 | 2002-07-26 | Exhaust emission control system |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001226573 | 2001-07-26 | ||
| JP2001-226573 | 2001-07-26 | ||
| JP2002213573A JP2003129835A (en) | 2001-07-26 | 2002-07-23 | Exhaust emission control device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2003129835A true JP2003129835A (en) | 2003-05-08 |
Family
ID=26619357
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2002213573A Withdrawn JP2003129835A (en) | 2001-07-26 | 2002-07-23 | Exhaust emission control device |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP2003129835A (en) |
| KR (1) | KR20030010542A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006075801A1 (en) * | 2005-01-17 | 2006-07-20 | Toyota Jidosha Kabushiki Kaisha | Exhaust emission control device regenerating system for internal combustion engine |
| JP2007023888A (en) * | 2005-07-15 | 2007-02-01 | Mitsubishi Motors Corp | Control device of internal combustion engine |
| WO2009038221A1 (en) | 2007-09-20 | 2009-03-26 | Toyota Jidosha Kabushiki Kaisha | Control apparatus for internal combustion engine |
| JP2009197763A (en) * | 2008-02-25 | 2009-09-03 | Honda Motor Co Ltd | Exhaust gas purifying apparatus for internal combustion engine |
| JP2011530029A (en) * | 2008-08-01 | 2011-12-15 | エミテック ゲゼルシヤフト フユア エミツシオンス テクノロギー ミツト ベシユレンクテル ハフツング | Method for operating an exhaust gas system with lambda control |
| JP2019138178A (en) * | 2018-02-07 | 2019-08-22 | 株式会社豊田中央研究所 | Exhaust emission control device of internal combustion engine, air-fuel ratio calculation device and method |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH062532A (en) * | 1992-06-17 | 1994-01-11 | Toyota Autom Loom Works Ltd | Exhaust emission control device for diesel engine |
| JPH06137133A (en) * | 1992-10-27 | 1994-05-17 | Nippondenso Co Ltd | Exhaust emission control device for internal combustion engine |
| JPH07317530A (en) * | 1994-05-20 | 1995-12-05 | Nippondenso Co Ltd | Exhaust emission control device of diesel engine |
| KR960001919U (en) * | 1994-06-02 | 1996-01-19 | 박연태 | Roof Tile |
-
2002
- 2002-07-23 JP JP2002213573A patent/JP2003129835A/en not_active Withdrawn
- 2002-07-26 KR KR1020020044078A patent/KR20030010542A/en active Search and Examination
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006075801A1 (en) * | 2005-01-17 | 2006-07-20 | Toyota Jidosha Kabushiki Kaisha | Exhaust emission control device regenerating system for internal combustion engine |
| JP2006194212A (en) * | 2005-01-17 | 2006-07-27 | Toyota Motor Corp | Exhaust emission control device regeneration system of internal combustion engine |
| US7730720B2 (en) | 2005-01-17 | 2010-06-08 | Toyota Jidosha Kabushiki Kaisha | Exhaust gas purification apparatus regeneration system of internal combustion engine |
| JP2007023888A (en) * | 2005-07-15 | 2007-02-01 | Mitsubishi Motors Corp | Control device of internal combustion engine |
| WO2009038221A1 (en) | 2007-09-20 | 2009-03-26 | Toyota Jidosha Kabushiki Kaisha | Control apparatus for internal combustion engine |
| US8266898B2 (en) | 2007-09-20 | 2012-09-18 | Toyota Jidosha Kabushiki Kaisha | Control apparatus for internal combustion engine |
| JP2009197763A (en) * | 2008-02-25 | 2009-09-03 | Honda Motor Co Ltd | Exhaust gas purifying apparatus for internal combustion engine |
| JP2011530029A (en) * | 2008-08-01 | 2011-12-15 | エミテック ゲゼルシヤフト フユア エミツシオンス テクノロギー ミツト ベシユレンクテル ハフツング | Method for operating an exhaust gas system with lambda control |
| JP2019138178A (en) * | 2018-02-07 | 2019-08-22 | 株式会社豊田中央研究所 | Exhaust emission control device of internal combustion engine, air-fuel ratio calculation device and method |
| JP7062986B2 (en) | 2018-02-07 | 2022-05-09 | 株式会社豊田中央研究所 | Exhaust purification device for internal combustion engine |
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| Publication number | Publication date |
|---|---|
| KR20030010542A (en) | 2003-02-05 |
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