JPH0693848A - Exhaust emission control device for internal combustion engine - Google Patents

Exhaust emission control device for internal combustion engine

Info

Publication number
JPH0693848A
JPH0693848A JP4245229A JP24522992A JPH0693848A JP H0693848 A JPH0693848 A JP H0693848A JP 4245229 A JP4245229 A JP 4245229A JP 24522992 A JP24522992 A JP 24522992A JP H0693848 A JPH0693848 A JP H0693848A
Authority
JP
Japan
Prior art keywords
exhaust gas
purification catalyst
temperature
gas purification
catalyst
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.)
Pending
Application number
JP4245229A
Other languages
Japanese (ja)
Inventor
Hisashi Aoyama
尚志 青山
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nissan Motor Co Ltd
Original Assignee
Nissan Motor Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nissan Motor Co Ltd filed Critical Nissan Motor Co Ltd
Priority to JP4245229A priority Critical patent/JPH0693848A/en
Publication of JPH0693848A publication Critical patent/JPH0693848A/en
Pending legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/0807—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
    • F01N3/0828—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents characterised by the absorbed or adsorbed substances
    • F01N3/0835—Hydrocarbons
    • 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
    • F01N3/0807—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
    • F01N3/0871—Regulation of absorbents or adsorbents, e.g. purging
    • F01N3/0878—Bypassing absorbents or adsorbents
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2240/00—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being
    • F01N2240/18—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being an adsorber or absorber
    • 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
    • F01N2570/00—Exhaust treating apparatus eliminating, absorbing or adsorbing specific elements or compounds
    • F01N2570/12—Hydrocarbons
    • 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

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Exhaust Gas After Treatment (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)

Abstract

PURPOSE:To control the flow rate of exhaust containing desorbed HC into catalyst properly by increasing the degree of opening of a bypass passage in which an adsorbent is provided while holding temperature of catalyst at the specified value or higher after the activated condition is detected based on temperature of catalyst. CONSTITUTION:A catalyst 3 for purifying emission is provided in an exhaust passage 2 of an internal combustion engine 1. The exhaust passage 2 on the upper stream side of the catalyst 3 is branched into a main passage 4 and a bypass passage 6 in which an adsorbent 5 is provided. In this case, each temperature at an inlet and an outlet of the catalyst 3 is detected by each sensor 8, 9, respectively. Further, a control valve 7 which controls the ratio of degree of opening of these continuously is provided at a branch point in the downstream of each passage 4, 6. The degree of opening of the bypass passage 6 which controls the control valve 7 by a control unit 13 is increased while holding temperature of the catalyst at the predetermined value or more after activation of the catalyst 3 is detected based on temperature of each sensor 8, 9.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は、内燃機関の排気浄化装
置に関し、特に排気中のＨＣを一時的に吸着する機能を
備えた装置の改良に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purifying apparatus for an internal combustion engine, and more particularly to an improvement of an apparatus having a function of temporarily adsorbing HC in exhaust gas.

【０００２】[0002]

【従来の技術】車両用の内燃機関においては排気浄化の
ため、排気通路中に排気中のＨＣ (未燃ガス) ，ＣＯを
Ｈ2 Ｏ，ＣＯ2 に酸化する一方、ＮＯX をＮ2 に還元し
て浄化する三元浄化触媒と称される排気浄化用触媒が介
装されている。ところで前記排気中の有害成分の中、Ｈ
Ｃの排出量は特に排気温度に影響されやすい。即ち、貴
金属触媒を使用する場合でも、ＨＣの浄化には一般に３
００°Ｃ以上の触媒温度を必要とする。そのため、前記
三元触媒を備えただけの排気浄化装置では、機関の冷温
始動直後など排気温度の低い時には、ＨＣは前記触媒に
よって浄化されがたい。2. Description of the Related Art In an internal combustion engine for a vehicle, in order to purify exhaust gas, HC (unburned gas) and CO in the exhaust gas are oxidized into H 2 O and CO 2 in the exhaust passage, while NO X is converted into N 2 . An exhaust gas purification catalyst called a three-way purification catalyst that reduces and purifies is installed. By the way, of the harmful components in the exhaust gas, H
The discharge amount of C is particularly susceptible to the exhaust temperature. In other words, even if a noble metal catalyst is used, it is generally 3
A catalyst temperature of 00 ° C or higher is required. Therefore, in the exhaust gas purification device only including the three-way catalyst, it is difficult to purify the HC by the catalyst when the exhaust gas temperature is low, such as immediately after the engine is started cold.

【０００３】このため、車両用の排気浄化装置として、
特開昭６３−６８７１３号公報に示されるように、前記
排気浄化用触媒の上流側の排気通路にＨＣを吸着するた
めの吸着材を介装したものが提案されている。このもの
では、吸着材が低温時にはＨＣを吸着し、高温になると
吸着されたＨＣを脱離する特性があることを利用し、排
気浄化用触媒の上流の排気通路の一部に前記吸着材を介
装したバイパス通路を並列に接続して主通路とバイパス
通路とを選択的に開閉自由な構成とし、排気浄化用触媒
が活性化される前の低温時に前記バイパス通路を開いて
吸着材にＨＣを吸着しておき、一旦バイパス通路を閉じ
た後、高温になって排気浄化用触媒が活性化してから再
度バイパス通路を開いて吸着されたＨＣを脱離させて排
気浄化用触媒で浄化するようになっている。吸着材とし
ては、ゼオライトが吸着性に優れていることから例えば
モノリス担体にゼオライトをコーティングしたものが提
案されている。Therefore, as an exhaust emission control device for vehicles,
As disclosed in Japanese Patent Application Laid-Open No. 63-68713, there has been proposed one in which an adsorbent for adsorbing HC is interposed in the exhaust passage on the upstream side of the exhaust purification catalyst. This one utilizes the fact that the adsorbent adsorbs HC at low temperatures and desorbs the adsorbed HC at high temperatures, so that the adsorbent is provided in a part of the exhaust passage upstream of the exhaust purification catalyst. The inserted bypass passages are connected in parallel to selectively open and close the main passage and the bypass passage, and the bypass passage is opened at a low temperature before activation of the exhaust gas purification catalyst to cause HC to be adsorbent. After adsorbing, and once closing the bypass passage, the temperature becomes high and the exhaust purification catalyst is activated, and then the bypass passage is opened again to desorb the adsorbed HC and the exhaust purification catalyst purifies it. It has become. As the adsorbent, for example, a monolith carrier coated with zeolite has been proposed because zeolite has excellent adsorbability.

【０００４】[0004]

【発明が解決しようとする課題】ところで、かかる吸着
材を備えた排気浄化装置においては、排気浄化用触媒が
活性化されたことを検出すると、バイパス通路を全開し
て多量の排気を流入させるため、吸着剤に吸着されてい
たＨＣが急激、かつ、多量に脱離してしまい、活性化さ
れていた排気浄化用触媒が多量のＨＣの流入によって入
口温度を下げられ排気浄化性能を低下させてしまうとい
う問題点を生じていた。By the way, in the exhaust gas purification device provided with such an adsorbent, when it is detected that the exhaust gas purification catalyst is activated, the bypass passage is fully opened to allow a large amount of exhaust gas to flow therein. The HC adsorbed by the adsorbent is rapidly and largely desorbed, and the activated exhaust gas purification catalyst lowers the inlet temperature due to the inflow of a large amount of HC, and deteriorates the exhaust gas purification performance. Was causing problems.

【０００５】本発明は、このような従来の問題点に鑑み
なされたもので、ＨＣの脱離量を排気浄化用触媒の温度
低下を抑制しつつ制御することにより、排気浄化用性能
を良好に維持できるようにした内燃機関の排気浄化装置
を提供することを目的とする。The present invention has been made in view of the above-mentioned conventional problems. The exhaust purification performance is improved by controlling the desorption amount of HC while suppressing the temperature decrease of the exhaust purification catalyst. An object of the present invention is to provide an exhaust gas purification device for an internal combustion engine that can be maintained.

【０００６】[0006]

【課題を解決するための手段】このため本発明は、図１
に示すように機関の排気通路に排気浄化用触媒を備える
と共に、該排気浄化用触媒の上流の排気通路の一部を主
通路と該主通路に並列に接続され排気中のＨＣを低温時
に吸着し高温時に脱離する機能を有した吸着材を介装し
たバイパス通路とで構成し、排気温度状態に応じて前記
主通路とバイパス通路との開度を制御しつつ排気浄化用
触媒の活性化前の低温状態で吸着剤に排気中のＨＣを吸
着し、排気浄化用触媒の活性化後の高温状態で吸着剤に
吸着されたＨＣを脱離して排気浄化用触媒により浄化さ
せるようにした内燃機関の排気浄化装置において、前記
排気浄化用触媒の温度状態を検出する手段と、前記主通
路とバイパス通路との開度比を連続的に制御する手段
と、検出された排気浄化用触媒の温度状態に基づいて排
気浄化用触媒が活性化されたことを検出後、排気浄化用
触媒を設定温度以上に保持しつつ前記開度比制御手段を
介してバイパス通路の開度を増大制御する手段と、を含
んで構成した。Therefore, the present invention is based on FIG.
As shown in FIG. 3, an exhaust gas purification catalyst is provided in the exhaust gas passage of the engine, and a part of the exhaust gas passage upstream of the exhaust gas purification catalyst is connected in parallel to the main passage and the main passage to adsorb HC in the exhaust gas at low temperature. And a bypass passage having an adsorbent having a function of desorbing at high temperature, and activation of the exhaust purification catalyst while controlling the opening of the main passage and the bypass passage according to the exhaust temperature state. Internal combustion that adsorbs HC in the exhaust gas to the adsorbent in the previous low temperature state and desorbs HC adsorbed in the adsorbent in the high temperature state after activation of the exhaust gas purification catalyst to purify by the exhaust gas purification catalyst In an exhaust gas purification apparatus for an engine, means for detecting a temperature state of the exhaust gas purification catalyst, means for continuously controlling an opening ratio between the main passage and the bypass passage, and a detected temperature of the exhaust gas purification catalyst. Exhaust gas purification catalyst is activated based on state After detecting that it has been, and configured to include a means for increasing controlling the opening of the bypass passage through the opening ratio control unit while holding the exhaust gas purifying catalyst than the set temperature, the.

【０００７】また、アルコール燃料を使用可能な内燃機
関の場合、燃料中のアルコール濃度を検出する手段と、
検出されたアルコール濃度に応じて前記排気浄化用触媒
の設定温度を可変に設定する手段と、を含んで構成し
た。In the case of an internal combustion engine that can use alcohol fuel, means for detecting the alcohol concentration in the fuel,
And a means for variably setting the set temperature of the exhaust gas purification catalyst according to the detected alcohol concentration.

【０００８】[0008]

【作用】排気浄化用触媒の出口温度に基づいて、排気浄
化用触媒が活性化する前は、バイパス通路が開かれて吸
着剤に排気中のＨＣを吸着させる。その後、排気浄化用
触媒が活性化するまでは、バイパス通路を閉じて主通路
に排気を導く。この間に排気温度は吸着剤からＨＣを脱
離する温度に達するが、バイパス通路を閉じて排気が導
かれないので、脱離は行われない。According to the outlet temperature of the exhaust gas purification catalyst, before the exhaust gas purification catalyst is activated, the bypass passage is opened to adsorb the HC in the exhaust gas to the adsorbent. After that, the bypass passage is closed and the exhaust gas is guided to the main passage until the exhaust gas purification catalyst is activated. During this time, the exhaust gas temperature reaches the temperature at which HC is desorbed from the adsorbent, but since the exhaust gas is not guided by closing the bypass passage, desorption is not performed.

【０００９】排気浄化用触媒の温度状態、例えば出口温
度に基づいて排気浄化用触媒が活性化された状態を検出
すると、排気浄化用触媒の温度状態、例えば入口温度を
監視しつつバイパス通路を開いていって、設定温度以上
に保持しつつバイパス通路の開度を増大させる。これに
より、排気浄化用触媒の排気浄化性能を確保しつつ、基
準クランク角度に基準クランク角されたＨＣを脱離し、
脱離されたＨＣの浄化処理を迅速に行うことができる。When the temperature state of the exhaust purification catalyst, for example, the activated state of the exhaust purification catalyst is detected based on the outlet temperature, the bypass passage is opened while monitoring the temperature state of the exhaust purification catalyst, for example, the inlet temperature. Therefore, the opening degree of the bypass passage is increased while maintaining the temperature above the set temperature. As a result, while ensuring the exhaust purification performance of the exhaust purification catalyst, the HC with the reference crank angle at the reference crank angle is desorbed,
The desorbed HC can be quickly purified.

【００１０】また、アルコールを燃料として使用する内
燃機関の場合、排気浄化用触媒が同一の場合でも、活性
温度がアルコール濃度によって異なってくるため、ＨＣ
を基準レベル以上処理できるような設定温度に可変に設
定することにより、如何なるアルコール濃度に対しても
良好な排気浄化性能を保持できる。Further, in the case of an internal combustion engine that uses alcohol as fuel, even if the exhaust gas purifying catalyst is the same, the activation temperature varies depending on the alcohol concentration, so that the HC
By variably setting the set temperature so that the above can be processed at a reference level or higher, good exhaust gas purification performance can be maintained for any alcohol concentration.

【００１１】[0011]

【実施例】以下に本発明の実施例を図に基づいて説明す
る。本発明の一実施例の構成を示す図２において、内燃
機関１の排気通路２には、排気浄化用触媒 (三元触媒)
３が介装され、該排気浄化用触媒３より上流側の排気通
路２の一部が主通路４と、該主通路４と並列に接続され
吸着材５を介装したバイパス通路６とで構成されてい
る。前記主通路４とバイパス通路６との下流側の分岐点
には、これら主通路４とバイパス通路６との開度比を連
続的に制御する手段として電磁式の制御弁７が介装され
ている。Embodiments of the present invention will be described below with reference to the drawings. In FIG. 2 showing the configuration of an embodiment of the present invention, an exhaust gas purification catalyst (three-way catalyst) is provided in an exhaust passage 2 of an internal combustion engine 1.
3, a part of the exhaust passage 2 upstream of the exhaust purification catalyst 3 is composed of a main passage 4 and a bypass passage 6 connected in parallel with the main passage 4 and having an adsorbent 5 interposed therein. Has been done. An electromagnetic control valve 7 is installed at a branch point on the downstream side of the main passage 4 and the bypass passage 6 as a means for continuously controlling the opening ratio of the main passage 4 and the bypass passage 6. There is.

【００１２】また、前記排気浄化用触媒３の上流側の排
気通路２には排気浄化用触媒３の入口温度を検出する入
口温度センサ８が装着され、排気浄化用触媒３下流側の
排気通路２には排気浄化用触媒３の出口温度を検出する
出口温度センサ９が装着されている。これら入口温度セ
ンサ８及び出口温度センサ９は排気浄化用触媒３の温度
状態を検出する手段を構成する。An inlet temperature sensor 8 for detecting the inlet temperature of the exhaust purification catalyst 3 is mounted in the exhaust passage 2 upstream of the exhaust purification catalyst 3, and the exhaust passage 2 downstream of the exhaust purification catalyst 3 is mounted. An outlet temperature sensor 9 for detecting the outlet temperature of the exhaust gas purification catalyst 3 is attached to the. The inlet temperature sensor 8 and the outlet temperature sensor 9 constitute means for detecting the temperature state of the exhaust gas purification catalyst 3.

【００１３】前記入口温度センサ８及び出口温度センサ
９の各検出信号、その他スタータスイッチ10のＯＮ，Ｏ
ＦＦ信号、水温センサ11により検出される機関冷却水温
度 (水温) ＴW 信号、回転数センサ12により検出される
機関回転数Ｎ信号等がコントロールユニット13に入力さ
れ、コントロールユニット13は、これらからの温度検出
信号に基づいて、排気中ＨＣの吸着及び脱離制御を行
う。Each detection signal of the inlet temperature sensor 8 and the outlet temperature sensor 9 and other ON / O of the starter switch 10
The FF signal, the engine cooling water temperature (water temperature) T W signal detected by the water temperature sensor 11, the engine rotation speed N signal detected by the rotation speed sensor 12, etc. are input to the control unit 13, and the control unit 13 receives them. Adsorption and desorption control of HC in the exhaust gas is performed based on the temperature detection signal of.

【００１４】前記コントロールユニット10による排気中
ＨＣの吸着及び脱離制御を図３に示したフローチャート
に従って説明する。ステップ (図ではＳと記す。以下同
様) １では、スタータスイッチ10のＯＮ，ＯＦＦを判別
する。スタータスイッチ10がＯＮで機関が始動されてい
ると判別された場合は、ステップ２へ進み、前記制御弁
７をバイパス通路６の全開側に制御する。The control of adsorption and desorption of HC in the exhaust gas by the control unit 10 will be described with reference to the flow chart shown in FIG. In step (denoted as S in the drawing; the same applies hereinafter) 1, it is determined whether the starter switch 10 is ON or OFF. When it is determined that the starter switch 10 is ON and the engine is started, the routine proceeds to step 2, where the control valve 7 is controlled to the fully open side of the bypass passage 6.

【００１５】次いでステップ３へ進み、前記回転数セン
サ12により検出された機関回転数Ｎと、別途燃料噴射量
制御で演算され、機関負荷を代表する値である基本燃料
噴射量ＴP とを読み込む。ステップ４では、現在の運転
状態において所定の単位時間当りに吸着剤５に吸着され
る排気中ＨＣ量ｇi を、前記機関回転数Ｎと基本燃料噴
射量ＴP とに基づいてＲＯＭのマップから読み込む。こ
こで、ＲＯＭには図５に示すように、予め、機関回転数
Ｎと基本燃料噴射量ＴP とをパラメータとして区分され
る運転領域毎にＨＣ量ｇi が記憶されている。尚、ｇi
は実験的に求められるが排気流量に比例する値であり、
したがって、機関回転数Ｎと基本燃料噴射量ＴP に対し
て個々に比例する値である。また、前記所定の単位時間
は、このルーチンの実行周期に等しく設定されている。Next, the routine proceeds to step 3, where the engine speed N detected by the engine speed sensor 12 and the basic fuel injection amount T P , which is a value that is separately calculated and is representative of the engine load, are read. . In step 4, the current operating state the exhaust HC amount g i to be adsorbed to the adsorbent 5 per predetermined unit time, the ROM of the map based on the engine speed N and the basic fuel injection quantity T P Read. Here, in the ROM, as shown in FIG. 5, the HC amount g i is stored in advance for each operation region divided by the engine speed N and the basic fuel injection amount T P as parameters. Note that g i
Is obtained experimentally, but is a value proportional to the exhaust flow rate,
Therefore, the values are individually proportional to the engine speed N and the basic fuel injection amount T P. The predetermined unit time is set equal to the execution cycle of this routine.

【００１６】ステップ５では、前回までのＨＣの吸着総
量Ｇa に前記今回の吸着量ｇi を加算することにより、
ＨＣの吸着総量Ｇa を更新する。ステップ６では、水温
センサ11で検出される水温ＴW が所定値Ｔ1 より大であ
るか否かを判定する。そして、水温ＴW が所定値Ｔ1 以
下の場合は、ステップ２に戻るが、水温ＴWが所定値Ｔ
1 より大である場合は、ＨＣが脱離される温度近傍に達
したと判断し、ステップ７へ進んで制御弁７を主通路４
全開側へ切り換える。これにより、排気の略全量が主通
路４へ流れるので、温度上昇による吸着剤５からのＨＣ
の脱離を防止できる。In step 5, by adding the adsorption amount g i of this time to the total adsorption amount G a of HC up to the previous time,
The total HC adsorption amount G a is updated. In step 6, it is determined whether the water temperature T W detected by the water temperature sensor 11 is higher than a predetermined value T 1 . When the water temperature T W is equal to or lower than the predetermined value T 1 , the process returns to step 2, but the water temperature T W is the predetermined value T 1.
If it is larger than 1 , it is judged that the temperature has reached the temperature near which HC is desorbed, and the routine proceeds to step 7, where the control valve 7 is connected to the main passage 4
Switch to the fully open side. As a result, substantially the entire amount of exhaust gas flows into the main passage 4, so that the HC from the adsorbent 5 due to the temperature rise is increased.
Can be prevented from coming off.

【００１７】ステップ８では、出口温度センサ９により
検出される排気浄化用触媒３の出口温度Ｔc2が設定値Ｔ
50に達しているか否かにより、該排気浄化用触媒３が活
性化されているか否かを判定する。ここで、前記設定値
Ｔ50はＨＣを50％浄化しうる最低温度に設定されてい
る。出口温度ＴOUT が設定値Ｔ50に達するまでの間は、
ステップ７へ戻って主通路４を全開を保持し、設定値Ｔ
50に達すると、ステップ９以降へ進んで本発明に係る脱
離制御を開始する。At step 8, the outlet temperature T c2 of the exhaust gas purification catalyst 3 detected by the outlet temperature sensor 9 is set to a set value T.
Whether or not the exhaust gas purification catalyst 3 is activated is determined depending on whether or not it reaches 50 . Here, the set value T 50 is set to the lowest temperature at which HC can be purified by 50%. Until the outlet temperature T OUT reaches the set value T 50 ,
Return to step 7 and keep the main passage 4 fully open to set value T
When it reaches 50 , the routine proceeds to step 9 and thereafter to start the desorption control according to the present invention.

【００１８】まず、ステップ９では、前記吸着総量Ｇa
を後述するため使用される吸着剤５へのＨＣ残量Ｇz と
して初期セットする。ステップ10では、制御弁７の開度
をバイパス通路６開側へ微小量 (ステップモータの場
合、例えば１ステップ) 開く。ステップ11で制御弁７が
全開となったか否かを判定し、全開となるまではステッ
プ12へ進んで入口温度センサ８で検出される排気浄化用
触媒３の入口温度ＴINが前記設定値Ｔ50に達したか否か
を判定する。First, in step 9, the total amount of adsorption G a
Is initially set as the HC residual amount G z to the adsorbent 5 which will be used later. In step 10, the opening degree of the control valve 7 is opened to the opening side of the bypass passage 6 by a small amount (in the case of a step motor, for example, one step). In step 11, it is determined whether the control valve 7 is fully opened, and until it is fully opened, the process proceeds to step 12 and the inlet temperature T IN of the exhaust gas purification catalyst 3 detected by the inlet temperature sensor 8 is the set value T 1. Determine if 50 has been reached.

【００１９】入口温度ＴINが設定値Ｔ50に達していると
判定された場合は、バイパス通路６からの脱離されたＨ
Ｃを含んだ排気が導入されても、排気浄化用触媒３の温
度低下が低く保たれ、脱離されたＨＣを排気浄化用触媒
３で浄化しきれると判断してステップ13へ進む。ステッ
プ13では、脱離により吸着剤５に残留するＨＣ量を演算
する。ここで、具体的なＨＣ残量の演算方法について説
明する。吸着の場合と同様、図６に示すように単位時間
当りで、かつ、制御弁７の単位開度当りのＨＣの脱離量
Ｚi の実験的に求められた値が、ＲＯＭの機関回転数Ｎ
と基本燃料噴射量ＴP とをパラメータとするマップの各
運転領域毎に記憶されている。When it is determined that the inlet temperature T IN has reached the set value T 50 , the H released from the bypass passage 6 is released.
Even if the exhaust gas containing C is introduced, the temperature drop of the exhaust gas purification catalyst 3 is kept low, and it is judged that the desorbed HC can be completely purified by the exhaust gas purification catalyst 3 and the routine proceeds to step 13. In step 13, the amount of HC remaining in the adsorbent 5 due to desorption is calculated. Here, a specific method of calculating the HC remaining amount will be described. As in the case of adsorption, as shown in FIG. 6, the experimentally obtained value of the desorption amount Z i of HC per unit time and per unit opening of the control valve 7 is the engine speed of the ROM. N
And the basic fuel injection amount T P are stored for each operating region of the map.

【００２０】また、制御弁７の開度に応じた補正係数Ｋ
(全開を１とした時の開度毎の比率) が図７に示すよう
にＲＯＭのマップに記憶されている。ここで、制御弁７
の開度 (ステップ数) を検出するセンサを設けてもよい
が、駆動用にステップモータ等を用いる場合には、開度
量を積算して求めるようにしてもよい。上記各マップの
値を用いて、ＨＣの残量Ｇz を求めるステップ13のサブ
ルーチンを図４に従って説明する。Further, the correction coefficient K according to the opening degree of the control valve 7
(The ratio of each opening when the full opening is set to 1) is stored in the ROM map as shown in FIG. Here, the control valve 7
A sensor for detecting the opening degree (the number of steps) may be provided, but when a step motor or the like is used for driving, the opening amount may be integrated to obtain the value. The subroutine of step 13 for obtaining the HC remaining amount G z using the values of the above maps will be described with reference to FIG.

【００２１】ステップ131 では、機関回転数Ｎ，基本燃
料噴射量ＴP 及び制御弁７の開度θを読み込む。ステッ
プ132 では、前記単位時間，単位開度当りのＨＣ脱離量
Ｚi を、機関回転数Ｎ及び基本燃料噴射量ＴP に基づい
て、前記ＲＯＭのマップから検索する。ステップ133 で
は、制御弁７の開度θから、前記補正係数Ｋを検索す
る。In step 131, the engine speed N, the basic fuel injection amount T P and the opening degree θ of the control valve 7 are read. In step 132, the HC desorption amount Z i per unit time and unit opening is searched from the map of the ROM based on the engine speed N and the basic fuel injection amount T P. In step 133, the correction coefficient K is retrieved from the opening degree θ of the control valve 7.

【００２２】ステップ134 では、最新の残量Ｇz を次式
により更新して求める。 Ｇz ＝Ｇz −Ｋ・Ｚi 尚、脱離動作開始前の残量Ｇz の初期値は、前記したよ
うに吸着総量Ｇa に等しいから、Ｇz ＝Ｇa −Σ（Ｋ・
Ｚi ）である。このようにしてＨＣの残量Ｇz を求めた
後、図３に戻ってステップ14では、残量Ｇz が０となっ
たか、つまり脱離が完了したか否かを判定する。In step 134, the latest remaining amount G z is updated by the following equation. G z = G z −K · Z i Since the initial value of the remaining amount G z before the start of the desorption operation is equal to the total adsorption amount G a as described above, G z = G a −Σ (K ·
Z i ). After the remaining amount G z of HC is obtained in this way, returning to FIG. 3, it is determined in step 14 whether the remaining amount G z has become 0, that is, whether desorption has been completed.

【００２３】脱離が完了するまではステップ10に戻っ
て、更に、制御弁７を微小量開いて同様の操作を繰り返
す。この繰り返しにより、ステップ11で制御弁７の開度
が全開に達したと判定された場合には、ステップ15，1
6，17で前記ステップ12，13，14と同一の動作を行う
が、ステップ17で脱離が完了していないと判定された場
合は、それ以上制御弁７開度を増大できないので、ステ
ップ15へ戻る。Until the desorption is completed, the process returns to step 10, the control valve 7 is further opened by a small amount, and the same operation is repeated. If it is determined in step 11 that the opening degree of the control valve 7 has reached full opening by repeating this step, steps 15, 1
In steps 6 and 17, the same operations as those in steps 12, 13 and 14 are performed, but if it is determined in step 17 that the desorption is not completed, the control valve 7 opening cannot be increased any more, so step 15 Return to.

【００２４】一方、ステップ12で入口温度ＴINが設定値
Ｔ50に達していないと判定された場合は、バイパス通路
６から脱離されたＨＣを含んだ排気が導入されると、排
気浄化用触媒３の温度低下が大きく、脱離されたＨＣを
排気浄化用触媒３で浄化しきれないと判断してステップ
18へ進み、制御弁７の開度を前記微小量閉じる。次い
で、ステップ19でステップ13と同様にしてＨＣの残量Ｇ
z を演算した後、ステップ20で脱離が完了したか否かを
判定し、完了するまではステップ12に戻って同様の操作
を繰り返す。On the other hand, if it is determined in step 12 that the inlet temperature T IN has not reached the set value T 50 , when the exhaust gas containing HC desorbed from the bypass passage 6 is introduced, the exhaust gas is purified. It is judged that the temperature of the catalyst 3 has dropped so much that the desorbed HC cannot be completely purified by the exhaust purification catalyst 3
Proceeding to 18, the opening of the control valve 7 is closed by the minute amount. Next, in step 19, in the same way as in step 13, the remaining amount G of HC
After calculating z , it is determined in step 20 whether or not the desorption is completed, and the process is returned to step 12 and the same operation is repeated until the desorption is completed.

【００２５】そして、前記ステップ14，ステップ17又は
ステップ20で脱離が完了したと判定された場合にはステ
ップ21へ進んで制御弁７を駆動し、主通路４を全開とす
るように切り換える。脱離完了後は吸着剤５通過による
排気抵抗を無くすと共に、吸着剤５の耐久性向上を図る
ためである。かかる構成とすれば、排気浄化用触媒３が
活性状態を維持できる温度状態を保持できるように脱離
されたＨＣを含む排気の排気浄化用触媒３への流量を漸
増制御する構成としたため、脱離直後に排気浄化用触媒
３が温度低下で不活性状態に戻って排気浄化性能が低下
することを防止でき、図８に示すように脱離の開始から
終了まで安定したＨＣ浄化性能を保持することができ
る。When it is determined in step 14, step 17 or step 20 that the desorption is completed, the routine proceeds to step 21, where the control valve 7 is driven and the main passage 4 is switched to be fully opened. This is because after the desorption is completed, exhaust resistance due to passage of the adsorbent 5 is eliminated and the durability of the adsorbent 5 is improved. With such a configuration, the exhaust purification catalyst 3 is configured to gradually increase the flow rate of exhaust gas containing desorbed HC to the exhaust purification catalyst 3 so as to maintain a temperature state in which the exhaust purification catalyst 3 can maintain an active state. Immediately after the separation, it is possible to prevent the exhaust purification catalyst 3 from returning to the inactive state due to the temperature decrease and lowering the exhaust purification performance, and as shown in FIG. 8, maintain the stable HC purification performance from the start to the end of the desorption. be able to.

【００２６】次に、内燃機関が燃料の一部又は全部にア
ルコールを使用する場合の実施例について説明する。こ
の場合には、図２に鎖線で示すように、燃料供給系 (配
管又は燃料タンク等) に、燃料中のアルコール濃度を検
出するアルコールセンサ21を追加する。その他のハード
ウエアの構成は、前記実施例と同一である。Next, an embodiment in which the internal combustion engine uses alcohol as a part or all of fuel will be described. In this case, as shown by the chain line in FIG. 2, an alcohol sensor 21 for detecting the alcohol concentration in the fuel is added to the fuel supply system (pipe or fuel tank). The other hardware configuration is the same as that of the above embodiment.

【００２７】ここで、燃料中のアルコール例えばメタノ
ールの濃度に対して、前記排気中のＨＣを50％処理でき
る触媒温度Ｔ50は、図９に示すような傾向を有する。そ
こで、図９に示すアルコール濃度と触媒温度Ｔ50との関
係を、ＲＯＭにマップとして記憶しておく。そして、コ
ントロールユニット10による排気中ＨＣの吸着及び脱離
制御は図３のステップ12, 15において排気浄化用触媒３
の入口温度Ｔ INと設定値Ｔ50とを、比較する前に、前記
アルコールセンサ21で検出されたアルコール濃度を読み
込んでおいて、該アルコール濃度に応じて前記ＲＯＭに
記憶されたマップから対応する触媒温度Ｔ50を検索し、
その値を設定値Ｔ50として用いるようにすればよい。こ
のようにすれば、アルコールを燃料とする内燃機関にお
いても、良好な排気浄化性能を維持することができる。Here, the alcohol in the fuel, for example, methano
50% of the HC in the exhaust can be treated with respect to the concentration of
Catalyst temperature T50Has a tendency as shown in FIG. So
Here, the alcohol concentration and the catalyst temperature T shown in FIG.50Seki
The person in charge is stored in the ROM as a map. And
Adsorption and desorption of HC in exhaust gas by the control unit 10
The control is step 12 in FIG.,Exhaust purification catalyst 3 in 15
Inlet temperature T INAnd set value T50Before comparing
Read the alcohol concentration detected by the alcohol sensor 21.
It is stored in the ROM according to the alcohol concentration.
Corresponding catalyst temperature T from the stored map50Search for
That value is the set value T50It should be used as. This
In this way, the internal combustion engine that uses alcohol as fuel will
However, good exhaust gas purification performance can be maintained.

【００２８】[0028]

【発明の効果】以上説明してきたように本発明によれ
ば、脱離されたＨＣを含む排気の排気浄化用触媒への流
量を排気浄化用触媒の温度状態を監視しつつ適切に制御
する構成としたため、脱離の開始から終了まで安定した
ＨＣ浄化性能を保持することができる。As described above, according to the present invention, the flow rate of exhaust gas containing desorbed HC to the exhaust purification catalyst is controlled appropriately while monitoring the temperature state of the exhaust purification catalyst. Therefore, stable HC purification performance can be maintained from the start to the end of desorption.

【００２９】また、アルコールを燃料として使用する内
燃機関に対しても、アルコール濃度に応じて排気浄化用
触媒の温度状態をＨＣを基準レベル以上処理できるよう
に可変に設定することにより、良好な排気浄化性能を保
持できる。Also, for an internal combustion engine that uses alcohol as fuel, the exhaust gas purifying catalyst can be variably set according to the alcohol concentration so that HC can be treated at a level higher than a reference level. Purification performance can be maintained.

【図面の簡単な説明】[Brief description of drawings]

【図１】本発明の構成，機能を示すブロック図FIG. 1 is a block diagram showing the configuration and function of the present invention.

【図２】本発明の一実施例の構成を示す図FIG. 2 is a diagram showing a configuration of an embodiment of the present invention.

【図３】同上実施例の吸着剤の脱離制御ルーチンを示す
フローチャートFIG. 3 is a flowchart showing an adsorbent desorption control routine of the above embodiment.

【図４】同上脱離制御ルーチンの中で吸着剤へのＨＣ残
量を演算するサブルーチンのフローチャートを示す線図FIG. 4 is a diagram showing a flowchart of a subroutine for calculating the HC remaining amount to the adsorbent in the same desorption control routine.

【図５】同上実施例の吸着剤の単位時間当りのＨＣ吸着
量を運転領域別に記憶したマップFIG. 5 is a map in which the amount of HC adsorbed per unit time of the adsorbent of the above embodiment is stored for each operating region.

【図６】同じく吸着剤からの単位時間当り制御弁の単位
開度量当りの脱離量を運転領域別に記憶したマップFIG. 6 is a map in which the amount of desorption from the adsorbent per unit time per unit opening of the control valve is stored for each operating region.

【図７】同じく、吸着剤の脱離量演算用の制御弁開度に
よる補正係数を記憶したマップFIG. 7 is a map similarly storing a correction coefficient according to the control valve opening degree for calculating the desorption amount of the adsorbent.

【図８】同じく、排気浄化用触媒の入口温度の変化を従
来と比較して示した線図FIG. 8 is a diagram showing a change in the inlet temperature of the exhaust gas purification catalyst similarly to the conventional case.

【図９】燃料中のアルコール濃度と排気浄化用触媒の活
性化温度との関係を示す線図FIG. 9 is a diagram showing the relationship between the alcohol concentration in the fuel and the activation temperature of the exhaust gas purification catalyst.

【符号の説明】[Explanation of symbols]

１ 内燃機関 ２ 排気通路 ３ 排気浄化用触媒 ４ 主通路 ５ 吸着材 ６ バイパス通路 ７ 制御弁 ８ 入口温度センサ ９ 出口温度センサ 11 水温センサ 13 コントロールユニット 21 アルコールセンサ 1 Internal Combustion Engine 2 Exhaust Passage 3 Exhaust Purification Catalyst 4 Main Passage 5 Adsorbent 6 Bypass Passage 7 Control Valve 8 Inlet Temperature Sensor 9 Outlet Temperature Sensor 11 Water Temperature Sensor 13 Control Unit 21 Alcohol Sensor

───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.5 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｆ０１Ｎ 3/20 Ｐ Ｆ０２Ｄ 45/00 ３６０ Ｃ 7536−3Ｇ ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 5 Identification code Internal reference number FI technical display location F01N 3/20 P F02D 45/00 360 C 7536-3G

Claims (2)

【特許請求の範囲】[Claims] 【請求項１】機関の排気通路に排気浄化用触媒を備える
と共に、該排気浄化用触媒の上流の排気通路の一部を主
通路と該主通路に並列に接続され排気中のＨＣを低温時
に吸着し高温時に脱離する機能を有した吸着材を介装し
たバイパス通路とで構成し、排気温度状態に応じて前記
主通路とバイパス通路との開度を制御しつつ排気浄化用
触媒の活性化前の低温状態で吸着剤に排気中のＨＣを吸
着し、排気浄化用触媒の活性化後の高温状態で吸着剤に
吸着されたＨＣを脱離して排気浄化用触媒により浄化さ
せるようにした内燃機関の排気浄化装置において、前記
排気浄化用触媒の温度状態を検出する手段と、前記主通
路とバイパス通路との開度比を連続的に制御する手段
と、検出された排気浄化用触媒の温度状態に基づいて排
気浄化用触媒が活性化されたことを検出後、排気浄化用
触媒を設定温度以上に保持しつつ前記開度比制御手段を
介してバイパス通路の開度を増大制御する手段と、を含
んで構成したことを特徴とする内燃機関の排気浄化装
置。1. An exhaust gas purification catalyst is provided in an exhaust gas passage of an engine, and a part of an exhaust gas passage upstream of the exhaust gas purification catalyst is connected in parallel to a main passage and the main passage to keep HC in the exhaust gas at a low temperature. It is composed of a bypass passage through which an adsorbent having a function of adsorbing and desorbing at a high temperature is interposed, and the activity of the exhaust purification catalyst while controlling the opening of the main passage and the bypass passage according to the exhaust temperature state. The HC in the exhaust gas is adsorbed by the adsorbent in the low temperature state before conversion, and the HC adsorbed by the adsorbent is desorbed in the high temperature state after activation of the exhaust gas purification catalyst to be purified by the exhaust gas purification catalyst. In an exhaust gas purification apparatus for an internal combustion engine, means for detecting the temperature state of the exhaust gas purification catalyst, means for continuously controlling the opening ratio of the main passage and the bypass passage, and the detected exhaust gas purification catalyst Exhaust gas purification catalyst is activated based on temperature conditions After detecting that the exhaust purification catalyst is maintained at a temperature equal to or higher than a set temperature, a means for increasing the opening of the bypass passage through the opening ratio control means is included. Exhaust gas purification device for internal combustion engine. 【請求項２】内燃機関は、アルコール燃料を使用可能で
あり、燃料中のアルコール濃度を検出する手段と、検出
されたアルコール濃度に応じて前記排気浄化用触媒の設
定温度を可変に設定する手段と、を含んで構成したこと
を特徴とする請求項１に記載の内燃機関の排気浄化装
置。2. The internal combustion engine is capable of using alcohol fuel, means for detecting the alcohol concentration in the fuel, and means for variably setting the set temperature of the exhaust gas purification catalyst according to the detected alcohol concentration. The exhaust gas purification device for an internal combustion engine according to claim 1, wherein the exhaust gas purification device includes:
JP4245229A 1992-09-14 1992-09-14 Exhaust emission control device for internal combustion engine Pending JPH0693848A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP4245229A JPH0693848A (en) 1992-09-14 1992-09-14 Exhaust emission control device for internal combustion engine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP4245229A JPH0693848A (en) 1992-09-14 1992-09-14 Exhaust emission control device for internal combustion engine

Publications (1)

Publication Number Publication Date
JPH0693848A true JPH0693848A (en) 1994-04-05

Family

ID=17130579

Family Applications (1)

Application Number Title Priority Date Filing Date
JP4245229A Pending JPH0693848A (en) 1992-09-14 1992-09-14 Exhaust emission control device for internal combustion engine

Country Status (1)

Country Link
JP (1) JPH0693848A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007224749A (en) * 2006-02-21 2007-09-06 Toyota Motor Corp Sulfur poisoning recovery control device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007224749A (en) * 2006-02-21 2007-09-06 Toyota Motor Corp Sulfur poisoning recovery control device
JP4645471B2 (en) * 2006-02-21 2011-03-09 トヨタ自動車株式会社 Sulfur poisoning recovery control device

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