JPH09317524A - Nitrogen oxide cleaning apparatus for internal combustion engine - Google Patents
Nitrogen oxide cleaning apparatus for internal combustion engineInfo
- Publication number
- JPH09317524A JPH09317524A JP8160833A JP16083396A JPH09317524A JP H09317524 A JPH09317524 A JP H09317524A JP 8160833 A JP8160833 A JP 8160833A JP 16083396 A JP16083396 A JP 16083396A JP H09317524 A JPH09317524 A JP H09317524A
- Authority
- JP
- Japan
- Prior art keywords
- fuel injection
- temperature
- catalyst device
- catalyst
- cylinder
- 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.)
- Granted
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/008—Controlling each cylinder individually
- F02D41/0082—Controlling each cylinder individually per groups or banks
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
- B01D53/9404—Removing only nitrogen compounds
- B01D53/9409—Nitrogen oxides
- B01D53/9431—Processes characterised by a specific device
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
- B01D53/9445—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC]
- B01D53/9454—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC] characterised by a specific device
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
- B01D53/9495—Controlling the catalytic process
-
- 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
- F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
- F01N13/009—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
- F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
- F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
- F01N3/2053—By-passing catalytic reactors, e.g. to prevent overheating
-
- 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
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/021—Introducing corrections for particular conditions exterior to the engine
- F02D41/0235—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/30—Controlling fuel injection
- F02D41/38—Controlling fuel injection of the high pressure type
- F02D41/40—Controlling fuel injection of the high pressure type with means for controlling injection timing or duration
- F02D41/402—Multiple injections
- F02D41/405—Multiple injections with post injections
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D2200/00—Input parameters for engine control
- F02D2200/02—Input parameters for engine control the parameters being related to the engine
- F02D2200/08—Exhaust gas treatment apparatus parameters
- F02D2200/0802—Temperature of the exhaust gas treatment apparatus
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/40—Engine management systems
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- General Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Mechanical Engineering (AREA)
- Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- Environmental & Geological Engineering (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Toxicology (AREA)
- Exhaust Gas After Treatment (AREA)
- Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
Abstract
Description
【0001】[0001]
【技術分野】本発明は,内燃機関の排気ガスに含まれる
窒素酸化物を浄化する排気浄化装置に関するものであ
る。TECHNICAL FIELD The present invention relates to an exhaust gas purification device for purifying nitrogen oxides contained in exhaust gas of an internal combustion engine.
【0002】[0002]
【従来技術】ディーゼルエンジン等の内燃機関から排出
される窒素酸化物(NOx)は金属担持ゼオライト等を
用いた触媒装置を用いて浄化されている。そして,上記
触媒装置の浄化率は,図2の符号51の曲線に示すよう
に,特定の温度範囲(同図のT1〜T3,例えば200
〜300℃)でだけ高い浄化率を示している。また,こ
の窒素酸化物の触媒装置は,例えば燃料等のHC(炭化
水素)成分を添加することにより反応が促進されること
が知られている。そのため,触媒装置の上流から軽油等
の還元剤を供給して排気ガスと混合し,窒素酸化物の浄
化を促進する方法が提案されている。2. Description of the Related Art Nitrogen oxides (NOx) emitted from an internal combustion engine such as a diesel engine are purified by using a catalyst device using a metal-supported zeolite or the like. The purification rate of the catalyst device is, as shown by a curve 51 in FIG. 2, a specific temperature range (T1 to T3 in FIG.
It shows a high purification rate only at (~ 300 ° C). In addition, it is known that the reaction of this catalyst for nitrogen oxides is promoted by adding an HC (hydrocarbon) component such as fuel. Therefore, a method has been proposed in which a reducing agent such as light oil is supplied from the upstream of the catalyst device and mixed with the exhaust gas to promote purification of nitrogen oxides.
【0003】そして,上記観点だけから言えば,窒素酸
化物の浄化率を高めるためには,還元剤であるHCを多
く供給すれば良いことになる。しかしながら,HCの供
給を増やすとHCの反応熱により触媒装置の温度が上昇
し,上記図2に示したT2近傍の浄化率の良好な温度範
囲を越えてしまうこととなる。そのため,その状態に応
じて適当な量のHCを添加し,浄化率の高い状態に触媒
装置を維持する必要がある。From the above viewpoint alone, it is sufficient to supply a large amount of HC, which is a reducing agent, in order to increase the purification rate of nitrogen oxides. However, when the supply of HC is increased, the temperature of the catalyst device rises due to the heat of reaction of HC, which exceeds the temperature range in which the purification rate is good in the vicinity of T2 shown in FIG. Therefore, it is necessary to add an appropriate amount of HC according to the state and maintain the catalyst device in a state of high purification rate.
【0004】そこで,特開平4−214919号公報で
は,触媒とHC供給装置とを備えたユニットを複数設
け,所定の温度範囲にあるユニットに対してのみHC供
給装置を作動させて触媒の過熱を防止し,窒素酸化物の
浄化率を向上させる浄化装置が提案されている。Therefore, in Japanese Unexamined Patent Publication No. 4-214919, a plurality of units each having a catalyst and an HC supply device are provided, and the HC supply device is operated only for units within a predetermined temperature range to prevent the catalyst from overheating. A purifying device has been proposed which prevents the nitrogen oxides and improves the purification rate of nitrogen oxides.
【0005】[0005]
【解決しようとする課題】しかしながら,上記特開平4
−214919号公報に示された窒素酸化物浄化装置
は,触媒装置の数だけHC供給装置が必要となり,装置
の構成が複雑となり,大形でコストの高いものとなると
いう不具合がある。本発明は,かかる従来の問題点に鑑
みてなされたものであり,より簡素な構成により,窒素
酸化物の浄化率を高めることのできる優れた窒素酸化物
浄化装置を提供しようとするものである。However, Japanese Patent Application Laid-Open No.
The nitrogen oxide purifying device disclosed in Japanese Patent No. 214919 has a problem in that HC supply devices are required for the number of catalyst devices, the structure of the device is complicated, and the device is large and costly. The present invention has been made in view of the above conventional problems, and an object of the present invention is to provide an excellent nitrogen oxide purification device capable of increasing the purification rate of nitrogen oxides with a simpler configuration. .
【0006】[0006]
【課題の解決手段】請求項1の発明にかかる窒素酸化物
浄化装置は,触媒装置が排気通路の上流側に配置された
第1触媒装置と第1触媒装置の下流側に直列に配置され
た第2の触媒装置とからなると共に,全体の気筒が上記
第1触媒装置の上流に接続された第1の気筒群と上記第
1触媒装置と第2触媒装置との間の排気通路に接続され
た第2の気筒群とからなる。In a nitrogen oxide purifying device according to the invention of claim 1, a catalyst device is arranged in series on the downstream side of the first catalyst device and the first catalyst device where the catalyst device is arranged on the upstream side of the exhaust passage. A second catalyst device, and all cylinders are connected to a first cylinder group connected upstream of the first catalyst device and an exhaust passage between the first catalyst device and the second catalyst device. And a second cylinder group.
【0007】また,燃料噴射制御手段は,機関出力発生
のための主燃料噴射指令と,炭化水素供給のための後燃
料噴射指令とを各気筒毎または各気筒群毎に発する。そ
して,燃料噴射制御手段は,触媒温度判定手段により判
定した第1触媒装置及び第2触媒装置の温度に対応して
後燃料噴射の量を調整し,各触媒装置の過熱を抑制しつ
つ窒素酸化物の浄化率の最大化を図る。Further, the fuel injection control means issues a main fuel injection command for generating engine output and a post fuel injection command for supplying hydrocarbons for each cylinder or each cylinder group. Then, the fuel injection control means adjusts the amount of post-fuel injection in accordance with the temperatures of the first catalyst device and the second catalyst device determined by the catalyst temperature determination means, and suppresses overheating of each catalyst device while performing nitrogen oxidation. Maximize the purification rate of objects.
【0008】上記のように構成されているため,第1の
気筒群から排出された排気ガスは,第1の触媒装置に流
入し,一方第2の触媒装置には,第2の気筒群から排出
された排気ガスと第1触媒装置で浄化された排気ガスと
が流入する。そして,後燃料噴射量は気筒毎または気筒
群毎に設定できるから,第1触媒装置に供給されるHC
還元剤の量,即ち後燃料噴射の量と,第2触媒装置に供
給されるHC還元剤の量,即ち後燃料噴射の量とを別個
に設定することができる。Due to the above-mentioned structure, the exhaust gas discharged from the first cylinder group flows into the first catalyst device, while the second catalyst device receives from the second cylinder group. The exhaust gas discharged and the exhaust gas purified by the first catalyst device flow in. Since the post-fuel injection amount can be set for each cylinder or each cylinder group, the HC supplied to the first catalyst device can be set.
The amount of reducing agent, that is, the amount of post-fuel injection, and the amount of HC reducing agent supplied to the second catalytic device, that is, the amount of post-fuel injection, can be set separately.
【0009】それ故,触媒温度判定手段によって判定し
た第1,第2触媒装置の温度状態に合わせて適切なHC
還元剤を各触媒装置に供給することができる。即ち,無
駄なHC(後燃料)は触媒装置に供給せず,適切な量の
HC(後燃料)を供給し,触媒装置を出来るだけ浄化率
の高い状態に制御することが可能となる。なお,上記後
燃料噴射は,膨張行程または排気行程において噴射され
るから,気筒内の熱により窒素酸化物の還元に適したH
Cに変化させうるという効果も有している。Therefore, the HC appropriate for the temperature conditions of the first and second catalyst devices determined by the catalyst temperature determination means is used.
A reducing agent can be supplied to each catalytic device. That is, it is possible to supply an appropriate amount of HC (post fuel) to the catalyst device without supplying wasteful HC (post fuel) to the catalyst device and control the catalyst device to a state where the purification rate is as high as possible. Since the post fuel injection is injected during the expansion stroke or the exhaust stroke, H that is suitable for the reduction of nitrogen oxides due to the heat in the cylinder is used.
It also has the effect that it can be changed to C.
【0010】例えば,請求項2記載のように,触媒装置
の窒素酸化物の浄化率が極めて低いレベルで推移する低
温の第1の温度ゾーン(図2のT1以下)と,窒素酸化
物の浄化率が温度と共に上昇する第2の温度ゾーン(図
2のT1〜T2)と,窒素酸化物の浄化率が温度と共に
下降する第3の温度ゾーン(図2のT2〜T3)と,窒
素酸化物の浄化率が極めて低いレベルで推移する高温の
第4の温度ゾーン(図2のT3以上)とに温度ゾーンを
区分し,各温度ゾーン毎に各気筒または各気筒群に対す
る後燃料噴射量の大きさ及び配分比率を変化させること
により,効果的な窒素酸化物の浄化を達成することがで
きる(後述する実施形態例参照)。For example, as described in claim 2, a low temperature first temperature zone (T1 or less in FIG. 2) in which the purification rate of nitrogen oxides of the catalyst device changes at an extremely low level, and purification of nitrogen oxides A second temperature zone (T1 to T2 in FIG. 2) in which the rate increases with temperature, a third temperature zone (T2 to T3 in FIG. 2) in which the purification rate of nitrogen oxides decreases with temperature, and nitrogen oxides The temperature zone is divided into a high temperature fourth temperature zone (T3 or higher in FIG. 2) in which the purification rate of the engine changes at an extremely low level, and the amount of post fuel injection amount for each cylinder or each cylinder group is large for each temperature zone. By changing the thickness and the distribution ratio, it is possible to achieve effective purification of nitrogen oxides (see the embodiment example described later).
【0011】何故ならば,上記各温度ゾーンによって温
度に対する浄化率の増減傾向が全く異なってくるから,
その特性に適合した後燃料噴射の制御を行わないと浄化
率の最大化を図ることが出来ないからである。例えば,
第2の温度ゾーンと第3の温度ゾーンの間の関係では,
請求項3記載のように,第3の温度ゾーンにおいては,
第1の気筒群に属する気筒に対して第2の温度ゾーンに
おける後燃料噴射量よりも小さい後燃料噴射量を設定
し,第2の気筒群に属する気筒に対しては第2の温度ゾ
ーンにおける後燃料噴射量よりも大きい後燃料噴射量を
設定することが好ましい。This is because the increasing / decreasing tendency of the purification rate with respect to temperature is completely different depending on the temperature zones.
This is because the purification rate cannot be maximized unless the fuel injection is controlled after the characteristics are met. For example,
In the relationship between the second temperature zone and the third temperature zone,
As described in claim 3, in the third temperature zone,
A post-fuel injection amount smaller than the post-fuel injection amount in the second temperature zone is set for the cylinders belonging to the first cylinder group, and a cylinder in the second temperature zone is set for the cylinders belonging to the second cylinder group. It is preferable to set a post fuel injection amount that is larger than the post fuel injection amount.
【0012】即ち,第3の温度ゾーンでは,浄化率の最
大温度を過ぎた温度の高い上流の第1触媒装置の過昇温
を抑制する必要があり,一方,相対的に温度が低い第2
の触媒装置を高い浄化率の温度にするためには,通常H
Cを供給して浄化率を向上させることが適切な制御とな
るからである。That is, in the third temperature zone, it is necessary to suppress the excessive temperature rise of the upstream first catalyst device whose temperature is higher than the maximum temperature of the purification rate, while the second temperature is relatively low.
In order to raise the temperature of the catalytic converter of
This is because supplying C to improve the purification rate is an appropriate control.
【0013】なお,上記請求項1から請求項3の技術思
想に基づく構成は,触媒装置が2個の場合にのみ有効な
ものではなく,2個を越える3個以上の触媒装置を設け
る場合にも適用可能である。即ち,請求項4に記載のよ
うに触媒装置の数をN個とすると共に気筒をN個の気筒
群に分割し,各触媒装置の温度に対応して後燃料噴射の
量を調整し,各触媒装置の過熱を抑制しつつ窒素酸化物
の浄化率の最大化を図る。The structure based on the technical idea of claims 1 to 3 is not effective only when the number of catalyst devices is two, and when three or more catalyst devices exceeding two are provided. Is also applicable. That is, the number of catalyst devices is N as described in claim 4, the cylinder is divided into a group of N cylinders, and the amount of post-fuel injection is adjusted according to the temperature of each catalyst device. Maximize the purification rate of nitrogen oxides while suppressing overheating of the catalyst device.
【0014】そして,上記のように構成することによ
り,第Iの気筒群から排出された排気ガスは,第Iの触
媒装置に流入し,一方第(I+1)番目の触媒装置に
は,第(I+1)番目の気筒群から排出された排気ガス
と第I触媒装置で浄化された排気ガスとが流入する。そ
して,後燃料噴射量は気筒毎または気筒群毎に設定でき
るから,第I触媒装置に供給されるHC還元剤の量,即
ち後燃料噴射の量と,第(I+1)触媒装置に供給され
るHC還元剤の量,即ち後燃料噴射の量とを別個に設定
することができる。With the above configuration, the exhaust gas discharged from the I-th cylinder group flows into the I-th catalyst device, while the (I + 1) -th catalyst device has the ( The exhaust gas discharged from the (I + 1) th cylinder group and the exhaust gas purified by the I-th catalyst device flow in. Since the post-fuel injection amount can be set for each cylinder or each cylinder group, the amount of HC reducing agent supplied to the I-th catalyst device, that is, the post-fuel injection amount and the (I + 1) -th catalyst device are supplied. The amount of HC reducing agent, that is, the amount of post-fuel injection can be set separately.
【0015】それ故,触媒温度判定手段によって判定し
た第I,第(I+1)触媒装置の温度状態に合わせて適
切なHC還元剤を各触媒装置に供給することができる。
即ち,無駄なHC(後燃料)は触媒装置に供給せず,適
切な量のHC(後燃料)を供給し,触媒装置を出来るだ
け浄化率の高い状態に制御することが可能となる。そし
て,触媒装置が3個以上の場合にも請求項5,請求項6
記載の発明により,前記請求項2または請求項3と同様
の作用効果を奏することが可能となる。Therefore, it is possible to supply an appropriate HC reducing agent to each catalyst device in accordance with the temperature states of the I-th and (I + 1) -th catalyst devices judged by the catalyst temperature judging means.
That is, it is possible to supply an appropriate amount of HC (post fuel) to the catalyst device without supplying wasteful HC (post fuel) to the catalyst device and control the catalyst device to a state where the purification rate is as high as possible. Also, when the number of catalyst devices is three or more, claims 5 and 6
According to the described invention, it is possible to achieve the same operational effects as those of the second or third aspect.
【0016】また,上記請求項1から請求項6の各構成
において,更に請求項7記載のように,上流側に配置さ
れる触媒装置の窒素酸化物浄化可能温度範囲を,下流側
に配置される触媒装置の窒素酸化物浄化可能温度範囲よ
りも低温とすることが好ましい。このように構成するこ
とにより,始動時等において昇温の容易な上流側の触媒
装置を迅速に昇温し,より低い温度で素早く活性化する
ことが可能となるからである。Further, in each of the above-mentioned constitutions 1 to 6, the nitrogen oxide purifying temperature range of the catalyst device arranged on the upstream side is arranged on the downstream side as described in claim 7. It is preferable that the temperature is lower than the temperature range in which the nitrogen oxides of the catalyst device can be purified. With such a configuration, it becomes possible to quickly raise the temperature of the upstream catalytic device, which can be easily heated at the time of starting, etc., and activate it at a lower temperature quickly.
【0017】また,請求項8記載のように,気筒群にお
けるトータルの後燃料噴射量を設定し,その気筒群にお
ける全後燃料噴射をその気筒群内の一部の気筒に集中さ
せて噴射させるようにすることが好ましい。何故なら
ば,各気筒に均一に後燃料噴射量を設定した場合より,
一部の気筒に後燃料噴射を集中させることにより,噴射
させる気筒における後燃料噴射の噴射量を相対的に大き
くすることができ,燃料噴射手段は相対的に動作性能
(例えば弁の応答速度や操作可能な最小操作量)の低い
ものを用いることが可能となるからである。Further, as described in claim 8, the total amount of post-fuel injection in the cylinder group is set, and all the post-fuel injection in the cylinder group is concentrated and injected into a part of the cylinders in the cylinder group. It is preferable to do so. Because, compared to the case where the post fuel injection amount is set uniformly in each cylinder,
By concentrating the post-fuel injection in some of the cylinders, the injection amount of the post-fuel injection in the cylinders to be injected can be made relatively large, and the fuel injection means has a relatively high operating performance (for example, the response speed of the valve or This is because it is possible to use a low operable minimum operation amount.
【0018】また,請求項9記載のように,上記後燃料
噴射量に加えて,更に気筒群毎に主燃料噴射の量を調整
することにより,より適切に各触媒装置の過熱を抑制し
つつ窒素酸化物の浄化率の最大化を図ることが可能とな
る。即ち,気筒群におけるトータルの主燃料噴射量を調
整することにより,その気筒群の接続された触媒装置に
流入する排気ガスの量が変化し,これによって触媒装置
の昇温速度や降温速度を制御することが可能となるから
である。Further, as described in claim 9, by further adjusting the amount of main fuel injection for each cylinder group in addition to the post fuel injection amount, overheating of each catalyst device can be suppressed more appropriately. It is possible to maximize the purification rate of nitrogen oxides. That is, by adjusting the total main fuel injection amount in a cylinder group, the amount of exhaust gas flowing into the catalyst device connected to that cylinder group is changed, thereby controlling the heating rate and cooling rate of the catalyst device. It is possible to do so.
【0019】例えば,請求項11記載のように,触媒装
置が2つである場合には,前記第1の温度ゾーンにおい
ては主燃料噴射を第1の気筒群に集中させて第1触媒装
置の昇温を促進し,請求項2記載の前記第4の温度ゾー
ンにおいては主燃料噴射を第1の気筒群に集中させて第
2触媒装置の冷却を促進すると好適である。For example, when there are two catalyst devices as claimed in claim 11, in the first temperature zone, the main fuel injection is concentrated in the first cylinder group so that the first catalyst device is It is preferable to accelerate the temperature rise and to concentrate the main fuel injection in the first cylinder group in the fourth temperature zone of the second aspect to promote cooling of the second catalyst device.
【0020】即ち,前記第1の温度ゾーンにおいては主
燃料噴射を第1の気筒群に集中させることにより排気ガ
スの流入を第1触媒装置に集中して第1触媒装置の昇温
を促進し,第1触媒装置の浄化率を迅速に高めることが
可能となる。また,前記第4の温度ゾーンにおいては主
燃料噴射を第1の気筒群に集中させて排気ガスの流入を
第1触媒装置に集中して第2触媒装置を冷却し第2触媒
装置を浄化率の高いより低温の領域の移行させることが
可能となるからである。そして,後者の場合には,高い
浄化率を保持する第2触媒装置において全ての排気ガス
の窒素酸化物の浄化を行わせる。That is, in the first temperature zone, the main fuel injection is concentrated in the first cylinder group so that the inflow of exhaust gas is concentrated in the first catalyst device and the temperature rise of the first catalyst device is promoted. Thus, the purification rate of the first catalyst device can be rapidly increased. Further, in the fourth temperature zone, the main fuel injection is concentrated in the first cylinder group, the inflow of exhaust gas is concentrated in the first catalyst device, the second catalyst device is cooled, and the second catalyst device is purified. This is because it becomes possible to shift to a region of higher temperature and lower temperature. In the latter case, the nitrogen oxides in all the exhaust gas are purified by the second catalyst device which maintains a high purification rate.
【0021】そして,触媒装置の数をN個とし,より一
般化した場合にも,請求項10に記載のように,上流側
に位置する第I番目の触媒装置の温度が第1の温度ゾー
ンにある場合おいては主燃料噴射を第I番目の気筒群に
集中させて第I触媒装置の昇温を促進し,第4の温度ゾ
ーンにある場合においては主燃料噴射を第I番目の気筒
群に集中させて第(I+1)番目以降の下流の触媒装置
の冷却を促進することにより,同様の効果を得ることが
できる。When the number of catalyst devices is N and is generalized, the temperature of the I-th catalyst device located on the upstream side is set to the first temperature zone as described in claim 10. , The main fuel injection is concentrated in the I-th cylinder group to accelerate the temperature rise of the I-th catalyst device, and in the fourth temperature zone, the main fuel injection is performed in the I-th cylinder group. The same effect can be obtained by concentrating the groups to promote cooling of the downstream (I + 1) th catalytic devices.
【0022】[0022]
実施形態例1 本例は,図1に示すように,気筒81〜84毎に設けら
れた燃料噴射手段としての電磁弁式インジェクタ11〜
14と,燃料噴射手段(電磁弁式インジェクタ11〜1
4)を制御する燃料噴射制御手段としての電子制御装置
(ECU)40と,排気通路35,34に配置され窒素
酸化物を還元浄化する複数の触媒装置21,22と,各
触媒装置21,22の温度を測定する触媒温度判定手段
としての排気温度センサー24〜26と,少なくとも気
筒81〜84の行程位置を検知することの出来る運転状
態検知手段としてのエンジンの回転センサー28及びア
クセルセンサー29とを有する内燃機関の窒素酸化物浄
化装置1である。First Embodiment As shown in FIG. 1, the first embodiment includes solenoid valve injectors 11 to 11 as fuel injection means provided for each of the cylinders 81 to 84.
14 and fuel injection means (solenoid valve injectors 11 to 1)
4), an electronic control unit (ECU) 40 as a fuel injection control unit, a plurality of catalyst devices 21 and 22 arranged in the exhaust passages 35 and 34 for reducing and purifying nitrogen oxides, and the catalyst devices 21 and 22. Exhaust temperature sensors 24 to 26 as catalyst temperature determining means for measuring the temperature of the engine, and an engine rotation sensor 28 and an accelerator sensor 29 as operating state detecting means capable of detecting at least stroke positions of the cylinders 81 to 84. It is a nitrogen oxide purifying apparatus 1 for an internal combustion engine that has.
【0023】触媒装置21,22は,排気通路34〜3
7の上流側に配置された第1触媒装置21と,この第1
触媒装置21の下流側に直列に配置された第2の触媒装
置22とからなると共に,気筒81〜84は,第1触媒
装置21の上流に接続された第1の気筒81〜83群
と,第1触媒装置21と第2触媒装置22との間の排気
通路36に接続された第2の気筒84群とからなる(即
ち,請求項4記載のN=2に相当する)。The catalyst devices 21 and 22 have exhaust passages 34 to 3 respectively.
7, a first catalytic device 21 arranged upstream of the first catalytic device 21 and the first catalytic device 21.
The cylinders 81 to 84 are composed of a second catalyst device 22 arranged in series on the downstream side of the catalyst device 21, and the cylinders 81 to 84 are first cylinders 81 to 83 connected to the upstream side of the first catalyst device 21. It comprises a second group of cylinders 84 connected to the exhaust passage 36 between the first catalytic device 21 and the second catalytic device 22 (that is, corresponding to N = 2 in claim 4).
【0024】そして,燃料噴射制御手段としての電子制
御装置(ECU)40は,上記触媒温度判定手段及び上
記運転状況検知手段の出力信号を受け,圧縮上死点近傍
における機関出力発生のための主燃料噴射指令と,膨張
行程または排気行程における炭化水素供給のための後燃
料噴射指令とを上記燃料噴射手段に対して各気筒81〜
84毎に発し,第1触媒装置21または第2触媒装置2
2の温度に対応して各気筒81〜84または気筒81〜
83群,気筒84群に対する上記後燃料噴射の量(波形
b1〜b4,図3〜図6)を調整し,各触媒装置21,
22の過熱を抑制しつつ窒素酸化物の浄化率の最大化を
図る。An electronic control unit (ECU) 40 as fuel injection control means receives the output signals of the catalyst temperature determination means and the operation status detection means, and is a main engine for generating engine output near the compression top dead center. A fuel injection command and a post-fuel injection command for supplying hydrocarbons in the expansion stroke or exhaust stroke are sent to the fuel injection means for each cylinder 81-.
Emitted every 84, the first catalytic device 21 or the second catalytic device 2
Cylinder 81-84 or cylinder 81-corresponding to the temperature of 2
The amount of the post fuel injection for the 83 group and the cylinder 84 group (waveforms b1 to b4, FIGS. 3 to 6) is adjusted, and each catalyst device 21,
The purification rate of nitrogen oxides is maximized while suppressing overheating of No. 22.
【0025】即ち,燃料噴射制御手段(ECU40)
は,第1の触媒装置21の窒素酸化物の浄化率が極めて
低いレベルで推移する低温の第1の温度ゾーン(図2の
T<T1)と,第1の触媒装置21の窒素酸化物の浄化
率が温度Tと共に上昇する第2の温度ゾーン(図2のT
1<T<T2)と,第1の触媒装置21の窒素酸化物の
浄化率が温度Tと共に下降する第3の温度ゾーン(図2
のT2<T<T3)と,第1の触媒装置21の窒素酸化
物の浄化率が極めて低いレベルで推移する高温の第4の
温度ゾーン(図2のT>T3)とに温度ゾーンを区分
し,図3〜図6に示すように各温度ゾーン毎に各気筒8
1〜83群,気筒84群に対する前記後燃料噴射量(波
形b1〜b4)の大きさ及び配分比率を変化させる。That is, fuel injection control means (ECU 40)
Is a low temperature first temperature zone (T <T1 in FIG. 2) in which the purification rate of nitrogen oxides of the first catalyst device 21 changes at an extremely low level, and the nitrogen oxides of the first catalyst device 21. The second temperature zone where the purification rate increases with the temperature T (T in FIG. 2).
1 <T <T2), and the third temperature zone in which the purification rate of nitrogen oxides in the first catalyst device 21 decreases with the temperature T (see FIG. 2).
Of T2 <T <T3) and the fourth temperature zone of high temperature (T> T3 of FIG. 2) where the purification rate of nitrogen oxides of the first catalyst device 21 changes at an extremely low level. Then, as shown in FIGS. 3 to 6, each cylinder 8 is provided for each temperature zone.
The magnitude and distribution ratio of the post fuel injection amount (waveforms b1 to b4) for the groups 1 to 83 and the group of cylinders 84 are changed.
【0026】例えば,図5に示すように,第3の温度ゾ
ーンにおいては,第1の気筒群に属する気筒81〜83
に対して図4に示す第2の温度ゾーンにおける後燃料噴
射量(波形b1〜b3)よりも小さい後燃料噴射量(波
形b1〜b3)を設定し,第2の気筒群に属する気筒8
4に対しては図4に示す第2の温度ゾーンにおける後燃
料噴射量(波形b4)よりも大きい後燃料噴射量(波形
b4)を設定する。For example, as shown in FIG. 5, in the third temperature zone, the cylinders 81 to 83 belonging to the first cylinder group are included.
4 is set to a post-fuel injection amount (waveforms b1 to b3) smaller than the post-fuel injection amount (waveforms b1 to b3) in the second temperature zone shown in FIG.
For No. 4, a post fuel injection amount (waveform b4) larger than the post fuel injection amount (waveform b4) in the second temperature zone shown in FIG. 4 is set.
【0027】以下,それぞれについて説明を補足する。
図1に示すように,本例の内燃機関は,ディーゼルエン
ジン8であり,燃料ポンプ89から各電磁弁式インジェ
クタ11〜14に対して燃料が供給される。同図におい
て,符号88は,常時高圧状態で燃料が蓄積されている
燃料配管である。そして,第1気筒群の気筒81〜83
の排気管31〜33は一つの排気管35に集約されて,
第1触媒装置21に接続されている。また,第2気筒群
に属する気筒84の排気管34は,第1触媒装置21と
第2触媒装置22とを結ぶ排気管36に連結されてい
る。The following is a supplementary explanation of each.
As shown in FIG. 1, the internal combustion engine of this example is a diesel engine 8, and fuel is supplied from a fuel pump 89 to each of the solenoid valve injectors 11-14. In the figure, reference numeral 88 is a fuel pipe in which the fuel is constantly accumulated in a high pressure state. Then, the cylinders 81 to 83 of the first cylinder group
The exhaust pipes 31 to 33 are integrated into one exhaust pipe 35,
It is connected to the first catalyst device 21. The exhaust pipe 34 of the cylinder 84 belonging to the second cylinder group is connected to the exhaust pipe 36 that connects the first catalyst device 21 and the second catalyst device 22.
【0028】一方,図2は,触媒装置21,22の浄化
特性を示しており,符号51で示す曲線は,窒素酸化物
の浄化特性を示し,符号52で示す曲線は,炭化水素の
浄化特性を示している。即ち,触媒の温度TがT1未満
では,窒素酸化物もHCも浄化されず,触媒温度TがT
1以上となって始めて窒素酸化物とHCの浄化が実質的
に開始される。そして,窒素酸化物の浄化率が増加し,
やがて窒素酸化物の浄化率が最大となる温度T2を越え
ると,窒素酸化物の浄化率は減少し,触媒温度TがT3
以上では,窒素酸化物の浄化率はほぼ零となる。On the other hand, FIG. 2 shows the purification characteristics of the catalyst devices 21 and 22. The curve indicated by the reference numeral 51 indicates the purification characteristics of nitrogen oxides, and the curve indicated by the reference numeral 52 indicates the purification characteristics of hydrocarbons. Is shown. That is, when the temperature T of the catalyst is lower than T1, neither nitrogen oxide nor HC is purified, and the temperature T of the catalyst is T.
Only when it becomes 1 or more, the purification of nitrogen oxides and HC is substantially started. And the purification rate of nitrogen oxides increases,
When the temperature exceeds the temperature T2 at which the purification rate of nitrogen oxides becomes maximum, the purification rate of nitrogen oxides decreases and the catalyst temperature T rises to T3.
Above, the purification rate of nitrogen oxides is almost zero.
【0029】上記のように,触媒の温度が所定の温度範
囲T1〜T3にある場合しか,実質的な窒素酸化物の浄
化は行われない。例えば,ゼオライトにPtを担持した
触媒においては,上記T1は約200℃,T2は約25
0℃,T3は約300℃である。また,例えば,ゼオラ
イトにCuを担持またはイオン交換した触媒において
は,上記T1は約300℃,T2は約400℃,T3は
約500℃である。そして,前記のように,燃料等のH
C(炭化水素)成分を添加することにより窒素酸化物の
浄化反応を促進することが出来るわけであるが,一方こ
のHC添加により触媒装置の上流側での反応が増大し触
媒装置21,22の昇温により浄化率が低下するという
問題がある。As described above, substantial purification of nitrogen oxides is performed only when the temperature of the catalyst is within the predetermined temperature range T1 to T3. For example, in a catalyst in which Pt is supported on zeolite, the above T1 is about 200 ° C. and T2 is about 25
0 ° C and T3 are about 300 ° C. Further, for example, in a catalyst in which Cu is supported or ion-exchanged on zeolite, T1 is about 300 ° C, T2 is about 400 ° C, and T3 is about 500 ° C. Then, as described above, H of fuel etc.
Although the purifying reaction of nitrogen oxides can be promoted by adding a C (hydrocarbon) component, on the other hand, the addition of HC increases the reaction on the upstream side of the catalytic device, and the catalytic device 21, 22 There is a problem that the purification rate decreases due to the temperature rise.
【0030】次に,本例の窒素酸化物浄化装置1の動作
の態様につき,図3〜図7を用いて説明する。同図にお
いて,横軸はクランク角を示し縦軸は燃料の単位時間当
たりの噴射率を示す。図3は,第1触媒装置21の温度
が,T1未満即ち第1の温度ゾーンにある場合におい
て,ECU40の燃料噴射指令に基づく電磁弁式インジ
ェクタ11〜14の燃料噴射の波形を示すものである。
即ち,a1〜a4はそれぞれ気筒81〜84の主燃料噴
射量の波形を示し,b1〜b4はそれぞれ気筒81〜8
4の後燃料噴射量の波形を示している。また,同図にお
いて,UDは気筒の上死点をLDは下死点のタイミング
を示し,気筒の添え字1〜4は気筒81〜84に対応す
る。Next, the mode of operation of the nitrogen oxide purifying apparatus 1 of this embodiment will be described with reference to FIGS. In the figure, the horizontal axis represents the crank angle and the vertical axis represents the fuel injection rate per unit time. FIG. 3 shows a waveform of the fuel injection of the solenoid valve injectors 11 to 14 based on the fuel injection command of the ECU 40 when the temperature of the first catalyst device 21 is lower than T1, that is, in the first temperature zone. .
That is, a1 to a4 indicate the waveforms of the main fuel injection amounts of the cylinders 81 to 84, and b1 to b4 indicate the cylinders 81 to 8 respectively.
4 shows the waveform of the post fuel injection amount. Further, in the figure, UD indicates the timing of the top dead center of the cylinder, LD indicates the timing of the bottom dead center, and the subscripts 1 to 4 of the cylinder correspond to the cylinders 81 to 84.
【0031】そして,図4は,同様に第1触媒装置21
の温度が,T1以上T2未満即ち第2の温度ゾーンにあ
る場合にける電磁弁式インジェクタ11〜14の燃料噴
射の波形を示すものである。また,図5は,第1触媒装
置21の温度が,T2以上T3未満即ち第3の温度ゾー
ンにある場合の電磁弁式インジェクタ11〜14の燃料
噴射の波形を,図6は,第1触媒装置21の温度が,T
3以上即ち第4の温度ゾーンにある場合の電磁弁式イン
ジェクタ11〜14の燃料噴射の波形を示す。FIG. 4 also shows that the first catalyst device 21
Shows the waveform of the fuel injection of the solenoid valve injectors 11 to 14 when the temperature is above T1 and below T2, that is, in the second temperature zone. Further, FIG. 5 shows a waveform of fuel injection of the solenoid valve injectors 11 to 14 when the temperature of the first catalyst device 21 is in the range of T2 to less than T3, that is, the third temperature zone, and FIG. The temperature of the device 21 is T
The waveform of the fuel injection of the solenoid valve type injectors 11-14 in the case of being in the range of 3 or more, that is, in the fourth temperature zone is shown.
【0032】そして,図7は,本装置1の動作のフロー
チャートを示す。即ち,始めにステップ601におい
て,ECU40はアクセルセンサー29及び回転センサ
ー28並びに排気温度センサー24〜26の出力信号を
読み込む。そして,ステップ602において,アクセル
センサー29及び回転センサー28の信号から,機関出
力を得るための主燃料噴射量を算出する。次いで,ステ
ップ603において,排気温度センサー24〜26の出
力信号を基に第1触媒装置21及び第2触媒装置22の
触媒温度を推定する。Then, FIG. 7 shows a flowchart of the operation of the apparatus 1. That is, first, in step 601, the ECU 40 reads the output signals of the accelerator sensor 29, the rotation sensor 28, and the exhaust temperature sensors 24-26. Then, in step 602, the main fuel injection amount for obtaining the engine output is calculated from the signals of the accelerator sensor 29 and the rotation sensor 28. Next, at step 603, the catalyst temperatures of the first catalyst device 21 and the second catalyst device 22 are estimated based on the output signals of the exhaust temperature sensors 24-26.
【0033】第1触媒装置21の触媒温度の推定方法と
しては,例えば,簡便な方法としてその下流の排気温度
センサー25の排気温度を用いるという方法があり,ま
た,上流と下流の排気温度センサー24,25のうち高
い方を採用するという方法等がある。また,上流と下流
の排気温度センサー24,25の出力を加重平均した値
を用いる方法もある。As a method of estimating the catalyst temperature of the first catalyst device 21, for example, as a simple method, there is a method of using the exhaust temperature of the exhaust temperature sensor 25 at the downstream side, and the exhaust temperature sensor 24 at the upstream side and the downstream side. , 25, whichever is higher. There is also a method of using a weighted average value of the outputs of the upstream and downstream exhaust gas temperature sensors 24 and 25.
【0034】同様に,第2触媒装置22の触媒温度の判
定方法としては,例えば,簡便な方法としてその下流の
排気温度センサー26の排気温度を用いるという方法,
上流と下流の排気温度センサー25,26のうち高い方
を採用するという方法等がある。また,上流と下流の排
気温度センサー25,26の出力を加重平均した値を用
いる方法もある。Similarly, as a method of determining the catalyst temperature of the second catalyst device 22, for example, a method of using the exhaust temperature of the exhaust temperature sensor 26 downstream thereof as a simple method,
There is a method of adopting the higher one of the upstream and downstream exhaust gas temperature sensors 25 and 26. There is also a method of using a weighted average value of the outputs of the upstream and downstream exhaust gas temperature sensors 25 and 26.
【0035】そして,ステップ604で図2に示した第
1の境界温度即ち第1設定温度T1,第2の境界温度即
ち第1設定温度T2,第3の境界温度即ち第1設定温度
T3を読み込む。そして,ステップ605において,第
1触媒装置21の触媒温度Tが第1設定温度T1未満で
あるが否かを判定し,是ならばステップ606に進み,
否ならばステップ607に進む。Then, in step 604, the first boundary temperature or first set temperature T1, the second boundary temperature or first set temperature T2 and the third boundary temperature or first set temperature T3 shown in FIG. 2 are read. . Then, in step 605, it is determined whether or not the catalyst temperature T of the first catalyst device 21 is lower than the first set temperature T1, and if so, the process proceeds to step 606,
If not, the process proceeds to step 607.
【0036】そして,ステップ606に進んだ場合,即
ち第1触媒装置21の触媒温度が触媒活性開始温度T1
に達していない場合には,第1気筒群に属する気筒81
〜83の後燃料噴射量を零とする。また,第2気筒群
(気筒84)に対する後燃料噴射量は,第2触媒装置2
2の触媒温度Tsに対応した値に設定する。When the process proceeds to step 606, that is, the catalyst temperature of the first catalyst device 21 is the catalyst activation start temperature T1.
If the number of cylinders has not reached 80, the cylinders belonging to the first cylinder group 81
The post-fuel injection amount of ~ 83 is set to zero. Further, the post fuel injection amount for the second cylinder group (cylinder 84) is determined by the second catalyst device 2
The value is set to a value corresponding to the catalyst temperature Ts of 2.
【0037】即ち,下流の第2触媒装置22の触媒温度
は,通常は,第1触媒装置21の温度よりも低い。その
理由は,下流の第2触媒装置22に達する迄の間に放熱
により排気ガスの温度が低下するからである。従って,
通常の場合は,図3に示すように,第2触媒装置22の
後燃料噴射b4の量は零に設定される。That is, the catalyst temperature of the downstream second catalyst device 22 is usually lower than the temperature of the first catalyst device 21. The reason is that the temperature of the exhaust gas lowers due to heat dissipation before reaching the downstream second catalyst device 22. Therefore,
In the normal case, as shown in FIG. 3, the amount of the post fuel injection b4 of the second catalyst device 22 is set to zero.
【0038】しかしながら,触媒装置22の熱容量即ち
熱的な慣性により,第2触媒装置22の温度の方が第1
触媒装置21よりも高い場合があり,この場合には,そ
の温度Tsに応じて図2のカーブ51を勘案して窒素酸
化物の浄化率を高めに保持する後燃料噴射量に第2気筒
群(気筒84)の値を設定する。そして,ステップ62
0に進み,ECU40は上記設定量と図3に示すタイミ
ングにおいて電磁弁式インジェクタ11〜14に主燃料
噴射及び後燃料噴射を指令する。However, due to the heat capacity of the catalyst device 22, that is, thermal inertia, the temperature of the second catalyst device 22 is the first.
It may be higher than that of the catalyst device 21, and in this case, considering the curve 51 of FIG. 2 according to the temperature Ts, the second cylinder group is set to the post fuel injection amount for keeping the purification rate of nitrogen oxides high. The value of (cylinder 84) is set. And step 62
In step 0, the ECU 40 commands the solenoid valve injectors 11-14 to perform main fuel injection and post-fuel injection at the set amount and the timing shown in FIG.
【0039】図3における具体的な設定量の例は,例え
ばa1〜a4の量(積分値,以下同じ)は50mm3/
ストロークであり,b1〜b4の量は零である。即ち,
気筒81〜84の後噴射の総量は0mm3/エンジン2
回転であり,従って主燃料噴射量に対する後燃料噴射に
よる燃費の悪化率は0%である。これにより,触媒装置
21,22の未活性時には,無駄な後噴射を行わず燃費
の悪化を回避する。As an example of a concrete set amount in FIG. 3, for example, the amount of a1 to a4 (integrated value, the same applies hereinafter) is 50 mm3 /
It is a stroke, and the amount of b1 to b4 is zero. That is,
The total amount of post-injection of cylinders 81 to 84 is 0 mm3 / engine 2
Therefore, the deterioration rate of fuel efficiency due to the post fuel injection with respect to the main fuel injection amount is 0%. As a result, when the catalyst devices 21 and 22 are inactive, wasteful post-injection is not performed and deterioration of fuel efficiency is avoided.
【0040】一方,ステップ605の結果が否の場合に
は,ステップ607に進み,ステップ607において,
第1触媒装置21の触媒温度Tが第2設定温度T2未満
であるが否かを判定し,是ならばステップ608に進
み,否ならばステップ609に進む。そして,ステップ
608に進んだ場合,即ち第1触媒装置21の触媒温度
が触媒活性開始温度T1に達しているが最大温度T2未
満である場合(第2の温度ゾーンの時)には,図4に示
すように,第1気筒群に属する気筒81〜83の後燃料
噴射b1〜b3の量は比較的少なめの量A1とする。On the other hand, when the result of step 605 is negative, the process proceeds to step 607, and in step 607,
It is determined whether the catalyst temperature T of the first catalyst device 21 is lower than the second set temperature T2. If yes, the process proceeds to step 608, and if not, the process proceeds to step 609. When the process proceeds to step 608, that is, when the catalyst temperature of the first catalyst device 21 has reached the catalyst activation start temperature T1 but is lower than the maximum temperature T2 (in the second temperature zone), as shown in FIG. As shown in, the amount of the post fuel injection b1 to b3 of the cylinders 81 to 83 belonging to the first cylinder group is set to a relatively small amount A1.
【0041】その理由は,第1触媒装置21に流入する
排気ガスのHC濃度を高くすることにより直接的な効果
として窒素酸化物の浄化率を高めると共に,HCの反応
熱で第1触媒装置21を昇温し間接的な効果として浄化
率を高める為である。そして,この時,通常は供給され
たHCの全てが上流の触媒装置21で反応するわけでは
なく,未反応HCは下流の第2触媒装置22に流入す
る。そのため,第2触媒装置22においても残留HCの
反応による触媒装置22の昇温が生ずることとなる。The reason is that by increasing the HC concentration of the exhaust gas flowing into the first catalyst device 21, the purification rate of nitrogen oxides is directly increased, and at the same time, the reaction heat of the HC causes the first catalyst device 21 to react. Is to raise the purification rate as an indirect effect. At this time, normally, not all of the supplied HC reacts in the upstream catalyst device 21, and unreacted HC flows into the downstream second catalyst device 22. Therefore, in the second catalyst device 22 as well, the temperature rise of the catalyst device 22 occurs due to the reaction of the residual HC.
【0042】そして,第2触媒装置22の後燃料噴射量
は,第2触媒装置22の触媒温度Tsに対応した値A2
に設定する。即ち,下流の第2触媒装置22の触媒温度
が過昇温しないような量に,第2気筒群(気筒84)の
後燃料噴射量を設定する。そして,ステップ620に進
み,ECU40は上記設定量と図4に示すタイミングに
おいて電磁弁式インジェクタ11〜14に主燃料噴射及
び後燃料噴射を指令する。The post-fuel injection amount of the second catalyst device 22 is a value A2 corresponding to the catalyst temperature Ts of the second catalyst device 22.
Set to. That is, the post fuel injection amount of the second cylinder group (cylinder 84) is set to such an amount that the catalyst temperature of the downstream second catalyst device 22 does not excessively rise. Then, proceeding to step 620, the ECU 40 commands the solenoid valve injectors 11-14 to perform main fuel injection and post-fuel injection at the set amount and the timing shown in FIG.
【0043】図4における具体的な設定量の例は,例え
ば主燃料噴射a1〜a4の量は50mm3/ストローク
であり,第1気筒群の後燃料噴射b1〜b3の量A1
は,主燃料噴射量の2%に相当する1mm3/ストロー
ク,第2気筒群の後燃料噴射b4の量A2は,主燃料噴
射量の2%に相当する1mm3/ストロークである。即
ち,気筒81〜84の後噴射の総量は4mm3/エンジ
ン2回転であり,従って主燃料噴射量に対する後燃料噴
射による燃費の悪化率は2%である。As an example of a specific set amount in FIG. 4, for example, the amount of the main fuel injections a1 to a4 is 50 mm3 / stroke, and the amount A1 of the post fuel injection b1 to b3 of the first cylinder group.
Is 1 mm3 / stroke corresponding to 2% of the main fuel injection amount, and the amount A2 of the rear fuel injection b4 of the second cylinder group is 1 mm3 / stroke corresponding to 2% of the main fuel injection amount. That is, the total amount of post-injection of the cylinders 81 to 84 is 4 mm3 / 2 revolutions of the engine, and therefore the deterioration rate of fuel efficiency due to post-fuel injection is 2% with respect to the main fuel injection amount.
【0044】この場合,第2触媒装置22に流入する排
気ガスは,排気管34から流入する排気ガス(気筒84
の排気ガス)と第1触媒装置21で排出された排気ガス
の混合排気ガスであり,気筒84の排気ガスのHC濃度
は第1触媒装置21で排出されたHC濃度の低い排気ガ
スにより希釈化されるから,第2触媒装置22の排気ガ
スのHC濃度は第1触媒装置21の排気ガスHC濃度よ
りも低くなる。In this case, the exhaust gas flowing into the second catalyst device 22 is the exhaust gas flowing from the exhaust pipe 34 (the cylinder 84
Exhaust gas) and the exhaust gas exhausted by the first catalyst device 21, and the HC concentration of the exhaust gas of the cylinder 84 is diluted by the exhaust gas exhausted by the first catalyst device 21 and having a low HC concentration. Therefore, the HC concentration of the exhaust gas of the second catalyst device 22 becomes lower than the HC concentration of the exhaust gas of the first catalyst device 21.
【0045】一方,ステップ607の結果が否の場合に
は,ステップ609に進み,ステップ609において,
第1触媒装置21の触媒温度Tが第3設定温度T3未満
であるが否かを判定し,是ならばステップ610に進
み,否ならばステップ611に進む。そして,ステップ
610に進んだ場合,即ち第1触媒装置21の触媒温度
が浄化率最大温度T2以上で浄化停止温度T3未満であ
る場合(第3の温度ゾーンの時)には,第1気筒群に属
する気筒81〜83の後燃料噴射量は前記A1よりも小
さい量A3とする。On the other hand, when the result of step 607 is negative, the procedure proceeds to step 609, and in step 609,
It is determined whether the catalyst temperature T of the first catalyst device 21 is lower than the third set temperature T3. If yes, the process proceeds to step 610, and if not, the process proceeds to step 611. When the process proceeds to step 610, that is, when the catalyst temperature of the first catalyst device 21 is equal to or higher than the purification rate maximum temperature T2 and lower than the purification stop temperature T3 (in the third temperature zone), the first cylinder group The post-fuel injection amount of the cylinders 81 to 83 belonging to A3 is set to A3, which is smaller than A1.
【0046】その理由は,第1触媒装置21の過昇温を
防止するためである。即ち,上流にある第1触媒装置2
1ではHCがほぼ全量反応するが,後噴射量A3が少な
いため過昇温を抑制することが出来る。そして,第1触
媒装置21から流出し第2触媒装置22に流入する排気
ガスの温度は,放熱により低下する。そのため,第2触
媒装置22は,窒素酸化物の浄化率がより高い状態に調
整することが可能となる。即ち,通常は第2気筒群(気
筒84)に対する後燃料噴射量を前記A2よりも大きな
量A4とすることにより,第2触媒装置22の浄化率を
高めに保持することが出来る。The reason is to prevent excessive temperature rise of the first catalyst device 21. That is, the upstream first catalyst device 2
In the case of 1, almost all the HC reacts, but since the post injection amount A3 is small, it is possible to suppress the excessive temperature rise. Then, the temperature of the exhaust gas flowing out of the first catalytic device 21 and flowing into the second catalytic device 22 is lowered by heat radiation. Therefore, the second catalyst device 22 can be adjusted to a state where the purification rate of nitrogen oxides is higher. That is, normally, by setting the post fuel injection amount for the second cylinder group (cylinder 84) to A4 which is larger than A2, the purification rate of the second catalyst device 22 can be maintained at a high level.
【0047】そして,ステップ620に進み,ECU4
0は上記設定量と図5に示すタイミングにおいて電磁弁
式インジェクタ11〜14に主燃料噴射及び後燃料噴射
を指令する。図5における具体的な設定量の例は,例え
ば主燃料噴射a1〜a4の量は50mm3/ストローク
であり,第1気筒群の後燃料噴射b1〜b3の量A3
は,主燃料噴射量の1%に相当する0.5mm3/スト
ローク,第2気筒群の後燃料噴射b4の量A4は,主燃
料噴射量の5%に相当する2.5mm3/ストロークで
ある。即ち,気筒81〜84の後噴射の総量は4mm3
/エンジン2回転であり,従って主燃料噴射量に対する
後燃料噴射による燃費の悪化率は2%である。Then, the process proceeds to step 620 and the ECU 4
0 instructs the solenoid valve injectors 11 to 14 to perform main fuel injection and post-fuel injection at the set amount and the timing shown in FIG. As an example of a specific set amount in FIG. 5, for example, the amount of the main fuel injections a1 to a4 is 50 mm3 / stroke, and the amount A3 of the post fuel injection b1 to b3 of the first cylinder group is A3.
Is 0.5 mm3 / stroke corresponding to 1% of the main fuel injection amount, and the amount A4 of the rear fuel injection b4 of the second cylinder group is 2.5 mm3 / stroke corresponding to 5% of the main fuel injection amount. That is, the total amount of post injection of the cylinders 81 to 84 is 4 mm3.
Since the engine is rotated twice, the deterioration rate of fuel efficiency due to the post fuel injection with respect to the main fuel injection amount is 2%.
【0048】一方,ステップ611に進んだ場合,即ち
第1触媒装置21の触媒温度が浄化停止温度T3以上で
ある場合(第4の温度ゾーンの時)には,第1気筒群
(気筒81〜83)に対する後燃料噴射量は零にする。
一方,第2触媒装置22に流入する排気ガスの温度は,
放熱により第1触媒装置21の流出排気ガスよりも低く
なる。それ故,第2触媒装置22を窒素酸化物浄化可能
な状態,即ち第3の温度ゾーンとすることが可能な場合
があり,第2気筒群(気筒84)に対する後燃料噴射の
量は,第2触媒装置22の触媒温度Tsに対応した値に
設定する。On the other hand, when the routine proceeds to step 611, that is, when the catalyst temperature of the first catalyst device 21 is equal to or higher than the purification stop temperature T3 (in the fourth temperature zone), the first cylinder group (cylinders 81 to 81). The post fuel injection amount for 83) is set to zero.
On the other hand, the temperature of the exhaust gas flowing into the second catalyst device 22 is
Due to the heat radiation, it becomes lower than the exhaust gas flowing out of the first catalyst device 21. Therefore, there are cases where the second catalyst device 22 can be in a state where nitrogen oxides can be purified, that is, the third temperature zone, and the amount of post fuel injection to the second cylinder group (cylinder 84) is The temperature is set to a value corresponding to the catalyst temperature Ts of the two-catalyst device 22.
【0049】そして,ステップ620に進み,ECU4
0は上記設定量と図6に示すタイミングにおいて電磁弁
式インジェクタ11〜14に主燃料噴射及び後燃料噴射
を指令する。図6における具体的な設定量の例は,例え
ば主燃料噴射a1〜a4の量は50mm3/ストローク
であり,第1気筒群の後燃料噴射b1〜b3の量は零,
第2気筒群の後燃料噴射b4の量A5は,主燃料噴射量
の2%に相当する1mm3/ストロークである。即ち,
気筒81〜84の後噴射の総量は1mm3/エンジン2
回転であり,従って主燃料噴射量に対する後燃料噴射に
よる燃費の悪化率は0.5%である。Then, the process proceeds to step 620 and the ECU 4
0 commands the solenoid valve injectors 11 to 14 for main fuel injection and post-fuel injection at the set amount and the timing shown in FIG. As an example of the specific set amount in FIG. 6, for example, the amount of the main fuel injection a1 to a4 is 50 mm3 / stroke, the amount of the post fuel injection b1 to b3 of the first cylinder group is zero,
The amount A5 of the post fuel injection b4 of the second cylinder group is 1 mm3 / stroke, which corresponds to 2% of the main fuel injection amount. That is,
The total amount of post-injection of cylinders 81 to 84 is 1 mm3 / engine 2
Therefore, the deterioration rate of fuel efficiency due to the post fuel injection with respect to the main fuel injection amount is 0.5%.
【0050】図8は,本例の窒素酸化物浄化装置1の効
果を,本例のような制御を行わず後燃料噴射を一律に一
定量にした場合と比較して図示したものであり,横軸に
触媒装置に流入する排気ガスの温度を取り縦軸に窒素酸
化物の浄化率を%で示したものである。同図の符号54
で示す曲線は,第1触媒装置21及び第2触媒装置22
の触媒温度T,Tsによらず気筒81〜84に対する後
燃料噴射量を小さめの値,例えば0.5mm3/ストロ
ークにした場合の浄化特性である。そして,符号55で
示す曲線は,第1触媒装置21及び第2触媒装置22の
触媒温度T,Tsによらず気筒81〜84に対する後燃
料噴射量を大きめの値,例えば1mm3/ストロークに
した場合の浄化特性である。FIG. 8 shows the effect of the nitrogen oxide purifying apparatus 1 of this example in comparison with the case where the post-fuel injection is uniformly set to a constant amount without performing the control as in this example. The horizontal axis shows the temperature of the exhaust gas flowing into the catalyst device, and the vertical axis shows the purification rate of nitrogen oxides in%. Reference numeral 54 in FIG.
The curves indicated by are the first catalyst device 21 and the second catalyst device 22.
Is a purification characteristic when the post fuel injection amount for the cylinders 81 to 84 is set to a small value, for example, 0.5 mm3 / stroke regardless of the catalyst temperatures T and Ts. The curve indicated by the reference numeral 55 is obtained when the post-fuel injection amount for the cylinders 81 to 84 is set to a relatively large value, for example, 1 mm3 / stroke, regardless of the catalyst temperatures T and Ts of the first catalyst device 21 and the second catalyst device 22. The purification characteristics of.
【0051】後者の特性(符号55)は,前者の特性
(符号54)に比較すると,HCの量を多くしたため流
入排気ガスの低温側ではHCの反応熱で触媒が昇温して
浄化率が向上し,最大浄化率が得られる排気ガス温度が
低下すると共にHCの増加により最大の浄化率の値も大
きくなる。しかしながら,高温排気ガスの側では,HC
の反応熱により触媒装置が過昇温し浄化率が低下する。Compared to the former characteristic (reference numeral 54), the latter characteristic (reference numeral 55) has a large amount of HC, so that the catalyst heats up due to the reaction heat of the HC on the low temperature side of the inflowing exhaust gas and the purification rate is improved. The value of the maximum purification rate increases as the amount of HC increases as the exhaust gas temperature at which the maximum purification rate is improved decreases. However, on the hot exhaust gas side, HC
The reaction device heats up the catalyst device excessively and the purification rate decreases.
【0052】一方,本例の窒素酸化物浄化装置1の場
合,即ち,第1触媒装置21の温度が低温(第2温度ゾ
ーン)の場合には全ての気筒81〜84の後噴射量を比
較的大きな値(例えば1mm3/ストローク)にし,第
1触媒装置21の温度がより高い(第3温度ゾーン)の
場合には第1気筒群(気筒81〜83)の後噴射量を小
さな値(例えば0.5mm3/ストロークとし第2気筒
群(気筒84)の後噴射量を大きな値(例えば2.5m
m3/ストローク)とした場合の特性を,符号56で示
す。同図から分かるように,本例の窒素酸化物浄化装置
1は,広い範囲の排気ガス温度領域で高い窒素酸化物の
浄化率を示す。On the other hand, in the case of the nitrogen oxide purifying apparatus 1 of this example, that is, when the temperature of the first catalyst device 21 is low (second temperature zone), the post injection amounts of all the cylinders 81 to 84 are compared. When the temperature of the first catalyst device 21 is higher (third temperature zone), the post-injection amount of the first cylinder group (cylinders 81 to 83) is set to a small value (for example, 1 mm3 / stroke). 0.5 mm3 / stroke and a large post-injection amount of the second cylinder group (cylinder 84) (for example, 2.5 m
The characteristic when m3 / stroke) is indicated by reference numeral 56. As can be seen from the figure, the nitrogen oxide purification device 1 of the present example shows a high purification rate of nitrogen oxides in a wide range of exhaust gas temperature range.
【0053】上記のように,本例によれば触媒の温度が
低い場合は昇温を促進し,触媒の温度が高い場合には,
過昇温を抑制し,広い範囲で高い窒素酸化物の浄化率を
達成することが出来る。そして,本例によれば装置が大
形化したり大幅に複雑化したりするようなこともない。As described above, according to this example, when the temperature of the catalyst is low, the temperature rise is promoted, and when the temperature of the catalyst is high,
It is possible to suppress excessive temperature rise and achieve a high nitrogen oxide purification rate over a wide range. Further, according to this example, the device does not become large-sized or significantly complicated.
【0054】なお,上記例では,触媒装置21,22が
合計2個の場合について説明したが,4気筒の場合には
最大4個の触媒装置を用いることが可能である。この場
合,触媒装置の数を多くすれば,それだけ構成が複雑と
なるが,窒素酸化物の浄化率は向上する。In the above example, the case of a total of two catalyst devices 21 and 22 has been described, but in the case of four cylinders, it is possible to use a maximum of four catalyst devices. In this case, if the number of catalyst devices is increased, the structure becomes more complicated, but the purification rate of nitrogen oxides is improved.
【0055】また,第1触媒装置21と第2触媒装置2
2とは,同一の特性のものを用いても良いが,異なった
特性の触媒装置21,22とすることもできる。後者の
場合には,特に,上流に配置する第1触媒装置21によ
り低温の領域で窒素酸化物の浄化が可能である触媒(例
えばPt/ゼオライト触媒)を用い,下流側の第2触媒
装置22により高温の領域で活性化する触媒(例えばC
u/ゼオライト触媒)を用いることにより,窒素酸化物
を浄化することの出来る温度範囲をより広くすることが
できると共に,上流側の触媒装置21は排気ガスの熱に
より早く昇温するから一段と迅速に触媒装置21を活性
化出来るという利点がある。Further, the first catalytic device 21 and the second catalytic device 2
The catalysts 2 and 1 may have the same characteristics, but may be catalyst devices 21 and 22 having different characteristics. In the latter case, in particular, a catalyst (for example, Pt / zeolite catalyst) capable of purifying nitrogen oxides in a low temperature region by the first catalyst device 21 arranged upstream is used, and the second catalyst device 22 on the downstream side is used. A catalyst that is activated in a high temperature range by
u / zeolite catalyst), the temperature range in which nitrogen oxides can be purified can be widened, and the temperature of the upstream catalyst device 21 rises faster due to the heat of the exhaust gas. There is an advantage that the catalyst device 21 can be activated.
【0056】なお,従来は,より低温で活性化する触媒
装置と高温で活性化する触媒装置とを直列に配置する場
合には,以下に述べる理由から,上流側により高温で活
性化する触媒装置を配置する方法が採用されていた。即
ち,その理由は,触媒装置の上流側からHCを供給する
場合に,上流側に低温で活性化する触媒を配置すると,
上流側の触媒装置でHCが全て反応してしまい,下流側
の触媒にHCが供給できなくなる恐れがあるとの理由に
よるものである。Conventionally, when a catalyst device which is activated at a lower temperature and a catalyst device which is activated at a higher temperature are arranged in series, a catalyst device which is activated at a higher temperature on the upstream side is provided for the following reason. The method of arranging was adopted. That is, the reason is that, when HC is supplied from the upstream side of the catalyst device, if a catalyst that is activated at low temperature is arranged on the upstream side,
This is because there is a risk that all HC will react in the upstream catalyst device and HC will not be able to be supplied to the downstream catalyst.
【0057】そして,このような方式を採用すると,ア
イドリングから加速を行う場合には,上流側にある昇温
の容易な触媒装置を速やかに活性化し窒素酸化物を浄化
したいのにも係わらず,上流側の触媒は高温にならない
と活性化しないため,モード走行では浄化率が低くなる
という結果をもたらしていた。しかしながら,本例で
は,上流の触媒装置21と下流の触媒装置22のそれぞ
れにHCを供給できるから,上記の理由による不具合は
発生せず,従って上流側に低温で活性化する触媒装置2
1を配置することにより何ら問題なく迅速に触媒装置を
立ち上げることが可能となる。When such a system is adopted, in the case of accelerating from idling, it is desired to promptly activate the catalyst device on the upstream side, which can easily raise the temperature, to purify the nitrogen oxides. The catalyst on the upstream side does not activate until it reaches a high temperature, resulting in a low purification rate in mode running. However, in this example, since HC can be supplied to each of the upstream catalyst device 21 and the downstream catalyst device 22, no trouble occurs due to the above reason, and therefore, the catalyst device 2 that is activated upstream at low temperature is used.
By disposing 1, the catalyst device can be started up quickly without any problems.
【0058】実施形態例2 本例は,図9に示すように,実施形態例1において,第
1気筒群(気筒81〜83)の後燃料噴射を1つの気筒
81(または82,83)において纏めて噴射させ,他
の気筒82,83は後噴射を実施しないようにしたもう
一つの実施形態例である。図9は実施形態例1の図4に
対応する状態(第2温度ゾーン)の燃料噴射波形を示す
ものである。また,本例では第2気筒群の気筒数が1個
の場合であるが,仮に第2気筒群が複数の気筒からなる
場合には,第2気筒群に属する1つの気筒のみが後噴射
を実施する。Second Embodiment In this embodiment, as shown in FIG. 9, in the first embodiment, the post fuel injection in the first cylinder group (cylinders 81 to 83) is performed in one cylinder 81 (or 82, 83). This is another embodiment example in which injection is performed collectively and the other cylinders 82 and 83 are not subjected to post injection. FIG. 9 shows a fuel injection waveform in a state (second temperature zone) corresponding to FIG. 4 of the first embodiment. Further, in this example, the number of cylinders in the second cylinder group is one. However, if the second cylinder group is composed of a plurality of cylinders, only one cylinder belonging to the second cylinder group will perform the post-injection. carry out.
【0059】例えば主燃料噴射a1〜a4の量は50m
m3/ストローク)であり,第1気筒群の後燃料噴射の
量は,気筒81の後噴射b1の量を主燃料噴射量の6%
に相当する3mm3/ストロークとし気筒82,83の
後噴射b2,b3の量を零とする。そして,第2気筒群
の後燃料噴射b4の量は,主燃料噴射量の2%に相当す
る1mm3/ストロークとする。即ち,気筒81〜84
の後噴射の総量は4mm3/エンジン2回転であり,従
って主燃料噴射量に対する後燃料噴射による燃費の悪化
率は2%である。For example, the amount of main fuel injection a1 to a4 is 50 m
m3 / stroke), and the post-fuel injection amount of the first cylinder group is 6% of the main fuel injection amount by the post-injection b1 of the cylinder 81.
Is set to 3 mm3 / stroke, and the amounts of post injection b2, b3 of the cylinders 82, 83 are set to zero. The amount of post fuel injection b4 of the second cylinder group is 1 mm3 / stroke, which corresponds to 2% of the main fuel injection amount. That is, the cylinders 81 to 84
The total amount of post-injection is 4 mm3 / 2 engine revolutions, so the fuel consumption deterioration rate due to post-fuel injection is 2% with respect to the main fuel injection amount.
【0060】本例によれば,電磁弁式インジェクタ11
〜14のうち,高感度,高速応答の電磁弁式インジェク
タは第1,第4の電磁弁式インジェクタ11,14だけ
でよい。それ故,インジェクタの小型化と低コスト化が
可能となり,また第2,第3の電磁弁式インジェクタ1
2,13の動作回数が半減化し耐久性も向上する。その
他については実施形態例1と同様である。According to this example, the solenoid valve injector 11
Among the above, the first and fourth solenoid valve injectors 11 and 14 are the only solenoid valve injectors with high sensitivity and high speed response. Therefore, the injector can be downsized and the cost can be reduced, and the second and third solenoid valve injectors 1 can be used.
The number of operations of Nos. 2 and 13 is halved and durability is also improved. Others are the same as those in the first embodiment.
【0061】実施形態例3 本例は,図10,図11に示すように,実施形態例1に
おいて,主燃料噴射量を第1気筒群と第2気筒群とで異
なった値としたもう一つの実施形態例である。即ち,エ
ンジンの運転状況,触媒装置21,22の温度に対応し
て主燃料噴射量を異なった量とする。Third Embodiment As shown in FIGS. 10 and 11, this embodiment is different from the first embodiment in that the main fuel injection amount is different between the first cylinder group and the second cylinder group. 3 is an example of one embodiment. That is, the main fuel injection amount is made different depending on the engine operating condition and the temperatures of the catalyst devices 21 and 22.
【0062】図10は,第1触媒装置21の触媒温度が
前記T1未満(第1温度ゾーン)の場合の電磁弁式イン
ジェクタ11〜14の燃料噴射の波形を示すものであ
り,実施形態例1の図3に対応する。第1気筒群(気筒
81〜83)の各気筒の主燃料噴射量は,同一量(例え
ば67mm3/ストローク)であり,第2気筒群の気筒
84の主燃料噴射量は零である。即ち,トータルの主燃
料の量は実施形態例1の図3と同じにし,その配分だけ
を変化させる。そして,第2気筒群の主燃料噴射が零で
あるため,気筒84はエアーポンプの作用をすることと
なる。FIG. 10 shows a waveform of fuel injection of the solenoid valve injectors 11 to 14 when the catalyst temperature of the first catalyst device 21 is lower than T1 (first temperature zone). 3 corresponds to FIG. The main fuel injection amount of each cylinder of the first cylinder group (cylinders 81 to 83) is the same amount (for example, 67 mm3 / stroke), and the main fuel injection amount of the cylinder 84 of the second cylinder group is zero. That is, the total amount of main fuel is the same as in FIG. 3 of the first embodiment, and only the distribution is changed. Then, since the main fuel injection in the second cylinder group is zero, the cylinder 84 functions as an air pump.
【0063】上記のように,第1気筒群の対してだけ主
燃料を分担させるから,第1触媒装置21に流入する排
気ガスの温度が高くなり,昇温が促進され,窒素酸化物
の浄化率が迅速に立ち上がることとなる。そして,後噴
射の量は,第1気筒群の気筒81〜83は少なめの値
(例えば1mm3/ストローク)とし,第2気筒の気筒
84は零である。第1気筒群に対して後燃料噴射を実施
する理由は,主燃料噴射により第1触媒装置21が急速
昇温し,急速に第1触媒装置21での窒素酸化物の浄化
が可能となるからである。As described above, since the main fuel is shared only by the first cylinder group, the temperature of the exhaust gas flowing into the first catalyst device 21 becomes high, the temperature rise is promoted, and the nitrogen oxides are purified. The rate will rise quickly. The amount of post-injection is set to a small value (for example, 1 mm3 / stroke) in the cylinders 81 to 83 of the first cylinder group, and zero in the second cylinder 84. The reason why the post fuel injection is performed on the first cylinder group is that the main catalyst injection causes the first catalyst device 21 to rapidly rise in temperature, and the nitrogen oxides can be rapidly purified by the first catalyst device 21. Is.
【0064】その結果,上記数値の場合の後噴射の総量
は3mm3/エンジン2回転であり,主燃料噴射量に対
する後噴射による燃費の悪化は平均して1.5%であ
る。また,第2気筒群の後噴射を零としたのは,第1気
筒群の気筒84がエアーポンプとなり第2触媒装置22
の温度が低下し,窒素酸化物の浄化作用を期待出来ない
からである。As a result, the total amount of post-injection in the case of the above values is 3 mm3 / 2 engine revolutions, and the deterioration of fuel efficiency due to post-injection with respect to the main fuel injection amount is 1.5% on average. Further, the post-injection of the second cylinder group is set to zero because the cylinder 84 of the first cylinder group serves as an air pump and the second catalyst device 22.
This is because the temperature of is decreased and the purification effect of nitrogen oxides cannot be expected.
【0065】一方,図11は,第1触媒装置21の触媒
温度が前記T3以上(第4温度ゾーン)の場合の電磁弁
式インジェクタ11〜14の燃料噴射の波形を示すもの
であり,実施形態例1の図6に対応する。第1気筒群
(気筒81〜83)の各気筒の主燃料噴射量は,同一量
(例えば67mm3/ストローク)であり,第2気筒群
の気筒84の主燃料噴射量は零である。即ち,トータル
の主燃料の量は実施形態例1の図6と同じにし,その配
分だけを変化させる。そして,第2気筒群の主燃料噴射
が零であるため,第2気筒群の気筒84はエアーポンプ
の作用をすることとなる。On the other hand, FIG. 11 shows a waveform of fuel injection of the solenoid valve injectors 11 to 14 when the catalyst temperature of the first catalyst device 21 is T3 or higher (fourth temperature zone). This corresponds to FIG. 6 of Example 1. The main fuel injection amount of each cylinder of the first cylinder group (cylinders 81 to 83) is the same amount (for example, 67 mm3 / stroke), and the main fuel injection amount of the cylinder 84 of the second cylinder group is zero. That is, the total amount of main fuel is the same as in FIG. 6 of the first embodiment, and only the distribution is changed. Since the main fuel injection of the second cylinder group is zero, the cylinder 84 of the second cylinder group acts as an air pump.
【0066】また,後噴射の量は,第1気筒群の気筒8
1〜83は零であり,第2気筒の気筒84は多めの値
(例えば4mm3/ストローク)である。それ故,後噴
射の総量は4mm3/エンジン2回転であり,主燃料噴
射量に対する後噴射による燃費の悪化は平均して2.0
%である。上記のように,第2気筒群の気筒84をエア
ーポンプとして作動させるから,下流の第2触媒装置2
2の温度が低下し,窒素酸化物の浄化可能な温度に保持
することができる。The amount of post-injection is the same as that of the cylinder 8 of the first cylinder group.
1 to 83 are zero, and the cylinder 84 of the second cylinder has a large value (for example, 4 mm3 / stroke). Therefore, the total amount of post-injection is 4 mm3 / 2 engine revolutions, and the deterioration of fuel efficiency due to post-injection with respect to the main fuel injection amount is 2.0 on average.
%. As described above, since the cylinder 84 of the second cylinder group is operated as an air pump, the second catalyst device 2 on the downstream side is operated.
The temperature of No. 2 is lowered, and it is possible to maintain the temperature at which nitrogen oxides can be purified.
【0067】そして,第1気筒群の後噴射を零としたの
は,第1触媒装置21が高温で浄化作用をすることが出
来ないからである。また,第2気筒群の気筒84の後噴
射量を大きめにしたのは,全ての気筒81〜84の排気
ガスが窒素酸化物を浄化することなく第2触媒装置22
に流入するため,HCを多めに投入し窒素酸化物の浄化
率を高めんとするためである。上記のように本例によれ
ば,第1触媒装置21が第1,第4の温度ゾーンにある
場合にも,触媒装置の浄化を促進する制御が実施可能と
なる。その他については実施形態例1と同様である。The reason why the post-injection of the first cylinder group is set to zero is that the first catalyst device 21 cannot perform the purifying action at a high temperature. Further, the post-injection amount of the cylinder 84 of the second cylinder group is made larger because the exhaust gas of all the cylinders 81 to 84 does not purify the nitrogen oxides but the second catalyst device 22.
This is because a large amount of HC is added to increase the purification rate of nitrogen oxides. As described above, according to this example, even when the first catalytic device 21 is in the first and fourth temperature zones, control that promotes purification of the catalytic device can be performed. Others are the same as those in the first embodiment.
【0068】実施形態例4 本例は,図12に示すように,実施形態例3において,
第1気筒群に属する気筒の数を2つとし,第2気筒群に
属する気筒の数を2つとしたもう一つの実施形態例であ
る。このようにすることにより,第1触媒装置21が第
1,第4温度ゾーンにある場合に,より広い温度範囲に
おいて,触媒装置21または触媒装置22による窒素酸
化物の浄化作用を発揮することが可能となる。Embodiment 4 As shown in FIG. 12, this embodiment is the same as Embodiment 3 except that
This is another embodiment example in which the number of cylinders belonging to the first cylinder group is two and the number of cylinders belonging to the second cylinder group is two. By doing so, when the first catalyst device 21 is in the first and fourth temperature zones, the catalyst device 21 or the catalyst device 22 can exert the nitrogen oxide purifying action in a wider temperature range. It will be possible.
【0069】即ち,第1温度ゾーンにある場合には,主
燃料を第1気筒群の2つの気筒81,83に集中し,3
つの気筒81〜83に集中した実施形態例3よりも第1
触媒装置21の昇温をより早めることができる。また,
第4温度ゾーンにある場合にも,第2気筒群に属する2
つの気筒82,84がエアーポンプの作用をすることに
なるから1つの気筒がエアーポンプの作用をした実施形
態例3の場合よりも第2触媒装置22の冷却が強めら
れ,第1触媒装置21のより広い温度範囲において第2
触媒装置22の浄化作用を維持することができる。その
他については実施形態例3と同様である。That is, when in the first temperature zone, the main fuel is concentrated in the two cylinders 81 and 83 of the first cylinder group,
1st rather than Embodiment 3 which concentrated on one cylinder 81-83
The temperature of the catalyst device 21 can be raised more quickly. Also,
Even if it is in the fourth temperature zone, the two cylinders belonging to the second cylinder group
Since the two cylinders 82 and 84 function as the air pump, the cooling of the second catalyst device 22 is strengthened more than the case of the third embodiment in which one cylinder functions as the air pump, and the first catalyst device 21 is cooled. Second in a wider temperature range of
The purifying action of the catalyst device 22 can be maintained. Others are the same as the third embodiment.
【0070】実施形態例5 本例は,図13に示すように,実施形態例1においてエ
ンジンの気筒81〜86及び電磁弁式インジェクタ11
〜16の数を6とし,第1気筒群に属する気筒81〜8
5を5つとし,第2気筒群に属する気筒86を1つとし
た例である。その他については実施形態例1と同様であ
る。Embodiment 5 As shown in FIG. 13, this embodiment is different from Embodiment 1 in that engine cylinders 81 to 86 and solenoid valve injector 11 are used.
The number of 16 to 16 is 6, and the cylinders 81 to 8 belonging to the first cylinder group
In this example, there are five cylinders and one cylinder 86 belonging to the second cylinder group. Others are the same as those in the first embodiment.
【0071】なお,上記において,触媒装置21,22
の数は2個に限定されるものではなく,3個以上として
もよい。また,第1気筒群の気筒数を4つの気筒として
第2気筒群の気筒の数を2気筒とすることもできる。そ
して,3気筒エンジン,8気筒エンジンにおいても同様
に各実施形態例の考え方を適用することができる。In the above, the catalyst devices 21, 22
Is not limited to two, but may be three or more. Further, the number of cylinders in the first cylinder group may be four, and the number of cylinders in the second cylinder group may be two. The concept of each embodiment can be similarly applied to the three-cylinder engine and the eight-cylinder engine.
【図1】実施形態例1の窒素酸化物浄化装置のシステム
構成図。FIG. 1 is a system configuration diagram of a nitrogen oxide purifying apparatus according to a first embodiment.
【図2】実施形態例1の窒素酸化物浄化装置の触媒温度
と浄化率の関係を示す図。FIG. 2 is a diagram showing a relationship between a catalyst temperature and a purification rate of the nitrogen oxide purifying apparatus according to the first embodiment.
【図3】実施形態例1の窒素酸化物浄化装置における気
筒毎の燃料噴射の波形を示す図(第1の温度ゾーン)。FIG. 3 is a diagram showing a waveform of fuel injection for each cylinder in the nitrogen oxide purifying apparatus according to the first embodiment (first temperature zone).
【図4】実施形態例1の窒素酸化物浄化装置における気
筒毎の燃料噴射の波形を示す図(第2の温度ゾーン)。FIG. 4 is a diagram showing a waveform of fuel injection for each cylinder in the nitrogen oxide purifying apparatus of the first embodiment (second temperature zone).
【図5】実施形態例1の窒素酸化物浄化装置における気
筒毎の燃料噴射の波形を示す図(第3の温度ゾーン)。FIG. 5 is a diagram showing a waveform of fuel injection for each cylinder in the nitrogen oxide purifying apparatus of the first embodiment (third temperature zone).
【図6】実施形態例1の窒素酸化物浄化装置における気
筒毎の燃料噴射の波形を示す図(第4の温度ゾーン)。FIG. 6 is a diagram showing a waveform of fuel injection for each cylinder in the nitrogen oxide purifying apparatus of the first embodiment (fourth temperature zone).
【図7】実施形態例1の窒素酸化物浄化装置の浄化特性
(符号56)を単純な制御を行った場合(符号54,5
5)と共に表示した図。FIG. 7 shows a case where the purification characteristics (reference numeral 56) of the nitrogen oxide purifying apparatus according to the first embodiment are simply controlled (reference numerals 54 and 5).
The figure displayed together with 5).
【図8】実施形態例1の窒素酸化物浄化装置の制御手順
を示すフローチャート。FIG. 8 is a flowchart showing a control procedure of the nitrogen oxide purifying apparatus according to the first embodiment.
【図9】実施形態例2の窒素酸化物浄化装置における気
筒毎の燃料噴射の波形を示す図(第2の温度ゾーン)。FIG. 9 is a diagram showing a waveform of fuel injection for each cylinder in the nitrogen oxide purifying apparatus of the second embodiment (second temperature zone).
【図10】実施形態例3の窒素酸化物浄化装置における
気筒毎の燃料噴射の波形を示す図(第1の温度ゾー
ン)。FIG. 10 is a diagram showing a waveform of fuel injection for each cylinder in the nitrogen oxide purifying apparatus of the third embodiment (first temperature zone).
【図11】実施形態例3の窒素酸化物浄化装置における
気筒毎の燃料噴射の波形を示す図(第4の温度ゾー
ン)。FIG. 11 is a diagram showing a waveform of fuel injection for each cylinder in the nitrogen oxide purifying apparatus of the third embodiment (fourth temperature zone).
【図12】実施形態例4の窒素酸化物浄化装置のシステ
ム構成図。FIG. 12 is a system configuration diagram of a nitrogen oxide purifying apparatus according to a fourth embodiment.
【図13】実施形態例5の窒素酸化物浄化装置のシステ
ム構成図。FIG. 13 is a system configuration diagram of a nitrogen oxide purifying apparatus according to a fifth embodiment.
1...窒素酸化物浄化装置, 11〜14...電磁弁式インジェクション(燃料噴射
手段), 21,22...触媒装置, 24〜26...排気温度センサー, 40...ECU(燃料噴射制御手段),1. . . Nitrogen oxide purifier, 11-14. . . Solenoid valve injection (fuel injection means), 21, 22. . . Catalyst device, 24-26. . . Exhaust temperature sensor, 40. . . ECU (fuel injection control means),
フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 FI 技術表示箇所 F01N 3/28 301 F01N 3/28 301G F02D 41/22 380 F02D 41/22 380D 385 385D 41/38 41/38 B 41/40 9523−3G 41/40 C 45/00 301 45/00 301C 312 312R (72)発明者 勝呂 肇 愛知県刈谷市昭和町1丁目1番地 日本電 装株式会社内Continuation of the front page (51) Int.Cl. 6 Identification number Office reference number FI Technical display location F01N 3/28 301 F01N 3/28 301G F02D 41/22 380 F02D 41/22 380D 385 385D 41/38 41/38 B 41/40 9523-3G 41/40 C 45/00 301 45/00 301C 312 312R (72) Inventor Hajime Suguro 1-1c Showa-cho, Kariya city, Aichi Prefecture NIPPON DENSO CORPORATION
Claims (11)
記燃料噴射手段を制御する燃料噴射制御手段と,排気通
路に配置され窒素酸化物を還元浄化する複数の触媒装置
と,上記触媒装置の温度を測定または推定する触媒温度
判定手段と,少なくとも気筒の行程位置を検知すること
の出来る運転状態検知手段とを有する内燃機関の窒素酸
化物浄化装置であって,上記触媒装置は,排気通路の上
流側に配置された第1触媒装置と,この第1触媒装置の
下流側に直列に配置された第2触媒装置とからなると共
に,上記気筒は上記第1触媒装置の上流に接続された第
1の気筒群と上記第1触媒装置と第2触媒装置との間の
排気通路に接続された第2の気筒群とからなり,上記燃
料噴射制御手段は,上記触媒温度判定手段及び運転状況
検知手段の出力信号を受け,圧縮上死点近傍における機
関出力発生のための主燃料噴射指令と,膨張行程または
排気行程における炭化水素供給のための後燃料噴射指令
とを上記燃料噴射手段に対して各気筒毎に発し,第1触
媒装置又は第2触媒装置の温度に対応して各気筒または
気筒群に対する上記後燃料噴射の量を調整し,各触媒装
置の過熱を抑制しつつ窒素酸化物の浄化率の最大化を図
ることを特徴とする内燃機関の窒素酸化物浄化装置。1. A fuel injection means provided for each cylinder, a fuel injection control means for controlling the fuel injection means, a plurality of catalyst devices arranged in an exhaust passage for reducing and purifying nitrogen oxides, and the catalyst device. A nitrogen oxide purifying apparatus for an internal combustion engine, comprising: a catalyst temperature determining means for measuring or estimating the temperature of the exhaust gas; and an operating condition detecting means capable of detecting at least the stroke position of the cylinder. Of the first catalyst device and a second catalyst device arranged in series downstream of the first catalyst device, and the cylinder is connected to the upstream side of the first catalyst device. The fuel injection control means includes a first cylinder group and a second cylinder group connected to an exhaust passage between the first catalyst device and the second catalyst device. Output signal of detection means Accordingly, a main fuel injection command for generating an engine output near the compression top dead center and a post fuel injection command for hydrocarbon supply in the expansion stroke or the exhaust stroke are supplied to the fuel injection means for each cylinder. The post-fuel injection amount for each cylinder or group of cylinders is adjusted in accordance with the temperature of the first catalyst device or the second catalyst device to suppress the overheating of each catalyst device while maximizing the purification rate of nitrogen oxides. A nitrogen oxide purifying device for an internal combustion engine, which is characterized in that
段は,第1の触媒装置の窒素酸化物の浄化率が極めて低
いレベルで推移する低温の第1の温度ゾーンと,第1の
触媒装置の窒素酸化物の浄化率が温度と共に上昇する第
2の温度ゾーンと,第1の触媒装置の窒素酸化物の浄化
率が温度と共に下降する第3の温度ゾーンと,第1の触
媒装置の窒素酸化物の浄化率が極めて低いレベルで推移
する高温の第4の温度ゾーンとに温度ゾーンを区分し,
各温度ゾーン毎に各気筒または各気筒群に対する前記後
燃料噴射量の大きさ及び配分比率を変化させることを特
徴とする内燃機関の窒素酸化物浄化装置。2. The low temperature first temperature zone in which the purification rate of nitrogen oxides in the first catalyst device changes at an extremely low level, and the first catalyst device in the fuel injection control means according to claim 1. Second temperature zone in which the purification rate of nitrogen oxides in the first catalytic device increases with temperature, a third temperature zone in which the purification rate of nitrogen oxides in the first catalytic device decreases with temperature, and nitrogen in the first catalytic device The temperature zone is divided into a high temperature fourth temperature zone where the purification rate of oxides changes at an extremely low level,
A nitrogen oxide purifying apparatus for an internal combustion engine, wherein the size and distribution ratio of the post fuel injection amount for each cylinder or each cylinder group is changed for each temperature zone.
段は,前記第3の温度ゾーンにおいては,第1の気筒群
に属する気筒に対して第2の温度ゾーンにおいて設定し
た後燃料噴射量よりも小さい後燃料噴射量を設定し,第
2の気筒群に属する気筒に対しては第2の温度ゾーンに
おいて設定した後燃料噴射量よりも大きい後燃料噴射量
を設定することを特徴とする内燃機関の窒素酸化物浄化
装置。3. The fuel injection control means according to claim 2, wherein, in the third temperature zone, the post-fuel injection amount is set for cylinders belonging to the first cylinder group in the second temperature zone. Internal combustion engine characterized by setting a post fuel injection amount that is smaller than the post fuel injection amount set in the second temperature zone for cylinders belonging to the second cylinder group. Nitrogen oxide purification equipment for engines.
記燃料噴射手段を制御する燃料噴射制御手段と,排気通
路に配置され窒素酸化物を還元浄化する複数の触媒装置
と,上記触媒装置の温度を測定または推定する触媒温度
判定手段と,少なくとも気筒の行程位置を検知すること
の出来る運転状態検知手段とを有する内燃機関の窒素酸
化物浄化装置であって,上記触媒装置は,上流側から第
1触媒装置,第2触媒装置,・・・,第N触媒装置の順
序で排気通路に直列に配置されたN個の触媒装置からな
り,一方,全体の気筒は,単一または複数の気筒によっ
て構成されるN個の気筒群からなると共に,第1の気筒
群は上記第1触媒装置の上流に接続され,1を越える自
然数Iにおける第I番目の気筒群は上記第(I−1)触
媒装置と第I触媒装置との間の排気通路に接続されてお
り,上記燃料噴射制御手段は,上記触媒温度判定手段及
び運転状況検知手段の出力信号を受け,圧縮上死点近傍
における機関出力発生のための主燃料噴射指令と,膨張
行程または排気行程における炭化水素供給のための後燃
料噴射指令とを上記燃料噴射手段に対して各気筒毎に発
し,上記N個の触媒装置の温度に対応して各気筒または
気筒群に対する上記後燃料噴射の量を調整し,各触媒装
置の過熱を抑制しつつ窒素酸化物の浄化率の最大化を図
ることを特徴とする内燃機関の窒素酸化物浄化装置。4. A fuel injection means provided for each cylinder, a fuel injection control means for controlling the fuel injection means, a plurality of catalyst devices arranged in an exhaust passage for reducing and purifying nitrogen oxides, and the catalyst device. A nitrogen oxide purifying apparatus for an internal combustion engine, comprising: a catalyst temperature determining means for measuring or estimating the temperature of the cylinder; and an operating state detecting means capable of detecting at least the stroke position of the cylinder. To the first catalytic device, the second catalytic device, ..., And the N-th catalytic device in the order of N catalytic devices arranged in series in the exhaust passage, while the entire cylinder has a single or a plurality of catalytic devices. The first cylinder group is connected upstream of the first catalyst device, and the I-th cylinder group with a natural number I exceeding 1 is the (I-1) th cylinder group. ) Catalytic device and No. I catalyst device Is connected to an exhaust passage between the fuel injection control means and the fuel injection control means, and the fuel injection control means receives the output signals of the catalyst temperature determination means and the operation status detection means and receives the output signals of the engine near the compression top dead center. An injection command and a post-fuel injection command for supplying hydrocarbons in the expansion stroke or exhaust stroke are issued to the fuel injection means for each cylinder, and the cylinders or the cylinders corresponding to the temperatures of the N catalyst devices are output. An apparatus for purifying nitrogen oxides in an internal combustion engine, wherein the amount of post-fuel injection for a cylinder group is adjusted to suppress overheating of each catalyst device while maximizing the purification rate of nitrogen oxides.
段は,各触媒装置の窒素酸化物の浄化率が極めて低いレ
ベルで推移する低温の第1の温度ゾーンと,各触媒装置
の窒素酸化物の浄化率が温度と共に上昇する第2の温度
ゾーンと,各触媒装置の窒素酸化物の浄化率が温度と共
に下降する第3の温度ゾーンと,各触媒装置の窒素酸化
物の浄化率が極めて低いレベルで推移する高温の第4の
温度ゾーンとに温度ゾーンを区分し,各温度ゾーン毎に
各気筒または各気筒群に対する前記後燃料噴射量の大き
さ及び配分比率を変化させることを特徴とする内燃機関
の窒素酸化物浄化装置。5. The fuel injection control means according to claim 4, wherein the low temperature first temperature zone in which the purification rate of nitrogen oxides in each catalyst device changes at an extremely low level, and the nitrogen oxides in each catalyst device Temperature zone in which the purification rate of NOx increases with temperature, a third temperature zone in which the purification rate of nitrogen oxides of each catalytic device decreases with temperature, and the purification rate of nitrogen oxides of each catalytic device is extremely low. It is characterized in that the temperature zone is divided into a high temperature fourth temperature zone which changes with the level, and the size and distribution ratio of the post fuel injection amount for each cylinder or each cylinder group is changed for each temperature zone. Nitrogen oxide purification device for internal combustion engine.
段は,前記第I番目の触媒装置の温度が前記第3の温度
ゾーンにある場合においては,第I番目の気筒群に属す
る気筒に対して第2の温度ゾーンにおいて設定した後燃
料噴射量よりも小さい後燃料噴射量を設定し,第(I+
1)番目以降の気筒群に属する気筒に対しては第2の温
度ゾーンにおいて設定した後燃料噴射量よりも大きい後
燃料噴射量を設定することを特徴とする内燃機関の窒素
酸化物浄化装置。6. The fuel injection control means according to claim 5, wherein when the temperature of the I-th catalyst device is in the third temperature zone, the fuel injection control means controls the cylinders belonging to the I-th cylinder group. Set a post fuel injection amount smaller than the post fuel injection amount set in the second temperature zone,
1) A nitrogen oxide purifying apparatus for an internal combustion engine, characterized in that a post fuel injection amount larger than a post fuel injection amount set in the second temperature zone is set for cylinders belonging to the first and subsequent cylinder groups.
おいて,前記触媒装置の特性は,上流側に配置される触
媒装置の窒素酸化物浄化可能温度範囲が,下流側に配置
される触媒装置の窒素酸化物浄化可能温度範囲よりも低
温であることを特徴とする内燃機関の窒素酸化物浄化装
置。7. The characteristic of the catalyst device according to any one of claims 1 to 6, wherein the catalyst device arranged upstream has a nitrogen oxide purifiable temperature range arranged downstream. A nitrogen oxide purifying apparatus for an internal combustion engine, which is at a temperature lower than a temperature range in which the catalytic device can purify nitrogen oxides.
おいて,前記燃料噴射制御手段は,気筒群におけるトー
タルの後燃料噴射量を設定し,その気筒群における後燃
料噴射をその気筒群内の一部の気筒に集中させて噴射さ
せることを特徴とする内燃機関の窒素酸化物浄化装置。8. The fuel injection control means according to claim 1, wherein the fuel injection control means sets a total post fuel injection amount in a cylinder group, and sets the post fuel injection in that cylinder group as the cylinder group. A nitrogen oxide purifying device for an internal combustion engine, characterized in that the fuel is concentrated and injected into a part of the cylinders.
おいて,前記燃料噴射制御手段は,前記後燃料噴射量に
加えて,更に気筒群毎に主燃料噴射の量を調整し,各触
媒装置の過熱を抑制しつつ窒素酸化物の浄化率の最大化
を図ることを特徴とする内燃機関の窒素酸化物浄化装
置。9. The fuel injection control means according to claim 1, wherein the fuel injection control means further adjusts a main fuel injection amount for each cylinder group in addition to the post fuel injection amount. An apparatus for purifying nitrogen oxides in an internal combustion engine, which maximizes a rate of purifying nitrogen oxides while suppressing overheating of the catalyst device.
第I番目の触媒装置の温度が,請求項2または請求項5
記載の前記第1の温度ゾーンにある場合おいては主燃料
噴射を第I番目の気筒群に集中させて第I触媒装置の昇
温を促進し,請求項2または請求項5記載の前記第4の
温度ゾーンにある場合においては主燃料噴射を第I番目
の気筒群に集中させて第(I+1)番目以降の下流の触
媒装置の冷却を促進することを特徴とする内燃機関の窒
素酸化物浄化装置。10. The temperature of the I-th catalytic device located on the upstream side according to claim 9,
When in the first temperature zone described, the main fuel injection is concentrated in the I-th cylinder group to accelerate the temperature rise of the I-th catalyst device. In the case of being in the temperature zone of No. 4, the main fuel injection is concentrated in the I-th cylinder group to promote the cooling of the (I + 1) th and subsequent downstream catalytic devices, and the nitrogen oxide of the internal combustion engine Purification device.
1,第2触媒装置からなり,前記燃料噴射制御手段は,
請求項2記載の前記第1の温度ゾーンにおいては主燃料
噴射を第1の気筒群に集中させて第1触媒装置の昇温を
促進し,請求項2記載の前記第4の温度ゾーンにおいて
は主燃料噴射を第1の気筒群に集中させて第2触媒装置
の冷却を促進することを特徴とする内燃機関の窒素酸化
物浄化装置。11. The catalyst device according to claim 9, wherein the catalyst device comprises first and second catalyst devices, and the fuel injection control means comprises:
In the first temperature zone of claim 2, the main fuel injection is concentrated in the first cylinder group to promote the temperature rise of the first catalyst device, and in the fourth temperature zone of claim 2, A nitrogen oxide purifying apparatus for an internal combustion engine, characterized in that main fuel injection is concentrated in a first cylinder group to promote cooling of a second catalyst device.
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP16083396A JP3750195B2 (en) | 1996-05-30 | 1996-05-30 | Nitrogen oxide purification device for internal combustion engine |
DE19722147A DE19722147B4 (en) | 1996-05-30 | 1997-05-27 | Exhaust emission cleaning device for purifying nitrogen oxides |
FR9706604A FR2749351B1 (en) | 1996-05-30 | 1997-05-29 | APPARATUS FOR CONVERTING NITROGEN OXIDES FOR AN INTERNAL COMBUSTION ENGINE |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP16083396A JP3750195B2 (en) | 1996-05-30 | 1996-05-30 | Nitrogen oxide purification device for internal combustion engine |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH09317524A true JPH09317524A (en) | 1997-12-09 |
JP3750195B2 JP3750195B2 (en) | 2006-03-01 |
Family
ID=15723406
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP16083396A Expired - Fee Related JP3750195B2 (en) | 1996-05-30 | 1996-05-30 | Nitrogen oxide purification device for internal combustion engine |
Country Status (3)
Country | Link |
---|---|
JP (1) | JP3750195B2 (en) |
DE (1) | DE19722147B4 (en) |
FR (1) | FR2749351B1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2002227635A (en) * | 2001-02-01 | 2002-08-14 | Honda Motor Co Ltd | Exhaust gas purifying device of internal combustion engine |
JP2008523321A (en) * | 2004-12-14 | 2008-07-03 | ルノー・エス・アー・エス | Protection of oxidation catalyst located upstream of particle filter for diesel engine due to injection fuel limitation |
US7950225B2 (en) | 2006-12-12 | 2011-05-31 | Honda Motor Co., Ltd. | Exhaust control system for an internal combustion engine |
Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2772425B1 (en) * | 1997-12-17 | 2000-03-03 | Renault | EXHAUST DEVICE FOR AN INTERNAL COMBUSTION ENGINE WITH LOW NITROGEN OXIDE EMISSION RATES AND METHOD FOR REDUCING NITROGEN OXIDES EMITTED IN EXHAUST GASES |
DE19963924A1 (en) * | 1999-12-31 | 2001-07-12 | Bosch Gmbh Robert | Method for operating a storage catalytic converter of an internal combustion engine |
DE19963932A1 (en) * | 1999-12-31 | 2001-07-12 | Bosch Gmbh Robert | Method for operating an internal combustion engine, in particular a motor vehicle |
DE10006609A1 (en) * | 2000-02-15 | 2001-08-30 | Bosch Gmbh Robert | Method for operating an internal combustion engine, in particular a motor vehicle |
FR2812689B1 (en) * | 2000-08-03 | 2003-04-04 | Peugeot Citroen Automobiles Sa | SYSTEM FOR AIDING THE REGENERATION OF A PARTICLE FILTER INTEGRATED IN AN EXHAUST LINE OF A DIESEL ENGINE OF A MOTOR VEHICLE |
DE10101593B4 (en) * | 2001-01-16 | 2010-07-15 | Bayerische Motoren Werke Aktiengesellschaft | Method for operating an internal combustion engine provided with direct fuel injection into the combustion chamber |
CN104364484B (en) * | 2012-06-28 | 2016-12-14 | 博世株式会社 | Apparatus for diagnosis of abnormality and the emission-control equipment of internal combustion engine |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5874841A (en) * | 1981-10-28 | 1983-05-06 | Nissan Motor Co Ltd | Cylinder number-controlled engine |
JPS62178740A (en) * | 1986-02-03 | 1987-08-05 | Toyota Motor Corp | Exhaust gas purifying device for multicylinder engine |
JP2825137B2 (en) * | 1990-06-25 | 1998-11-18 | トヨタ自動車株式会社 | Exhaust gas purification device for internal combustion engine |
JP2967113B2 (en) * | 1991-06-12 | 1999-10-25 | 株式会社豊田中央研究所 | Exhaust gas purification method |
EP0621400B1 (en) * | 1993-04-23 | 1999-03-31 | Daimler-Benz Aktiengesellschaft | Air compressing injection internal combustion engine with an exhaust gas treating device for reducing nitrous oxides |
-
1996
- 1996-05-30 JP JP16083396A patent/JP3750195B2/en not_active Expired - Fee Related
-
1997
- 1997-05-27 DE DE19722147A patent/DE19722147B4/en not_active Expired - Fee Related
- 1997-05-29 FR FR9706604A patent/FR2749351B1/en not_active Expired - Fee Related
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2002227635A (en) * | 2001-02-01 | 2002-08-14 | Honda Motor Co Ltd | Exhaust gas purifying device of internal combustion engine |
JP2008523321A (en) * | 2004-12-14 | 2008-07-03 | ルノー・エス・アー・エス | Protection of oxidation catalyst located upstream of particle filter for diesel engine due to injection fuel limitation |
US7950225B2 (en) | 2006-12-12 | 2011-05-31 | Honda Motor Co., Ltd. | Exhaust control system for an internal combustion engine |
Also Published As
Publication number | Publication date |
---|---|
FR2749351A1 (en) | 1997-12-05 |
DE19722147A1 (en) | 1997-12-04 |
FR2749351B1 (en) | 2001-03-02 |
DE19722147B4 (en) | 2006-05-24 |
JP3750195B2 (en) | 2006-03-01 |
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