JPH1182111A - Air-fuel ratio control device for internal combustion engine - Google Patents
Air-fuel ratio control device for internal combustion engineInfo
- Publication number
- JPH1182111A JPH1182111A JP9246409A JP24640997A JPH1182111A JP H1182111 A JPH1182111 A JP H1182111A JP 9246409 A JP9246409 A JP 9246409A JP 24640997 A JP24640997 A JP 24640997A JP H1182111 A JPH1182111 A JP H1182111A
- Authority
- JP
- Japan
- Prior art keywords
- air
- fuel ratio
- internal combustion
- combustion engine
- desorbed
- 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
Landscapes
- Combined Controls Of Internal Combustion Engines (AREA)
- Exhaust Gas After Treatment (AREA)
- Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、内燃機関の空燃比
制御装置に関する。The present invention relates to an air-fuel ratio control device for an internal combustion engine.
【0002】[0002]
【従来の技術】従来の内燃機関の空燃比制御装置として
は、例えば、特開平6−81637号公報に開示される
ようなものがある。このものは、内燃機関の排気通路に
HC吸着材を介装し、冷機時に排気中のHCを前記HC
吸着材に吸着させ、暖機完了後に前記HC吸着材からH
Cを脱離させ、この脱離されたHCを、前記HC吸着材
の排気下流部に配設された三元触媒により浄化するよう
になっている。そして、この脱離時に、脱離開始からの
経過時間に応じて、燃料噴射弁からの燃料噴射量により
内燃機関に吸入される混合気の空燃比をリーン側に制御
し、これによって三元触媒の入口における空燃比の適正
化を図るようにしていた。2. Description of the Related Art A conventional air-fuel ratio control device for an internal combustion engine is disclosed, for example, in JP-A-6-81637. In this type, an HC adsorbent is interposed in an exhaust passage of an internal combustion engine, and the HC in the exhaust gas at the time of cooling is removed by the HC.
After the warm-up is completed, the HC adsorbent absorbs H
C is desorbed, and the desorbed HC is purified by a three-way catalyst disposed downstream of the HC adsorbent in the exhaust gas. At the time of the desorption, the air-fuel ratio of the air-fuel mixture sucked into the internal combustion engine is controlled to the lean side by the fuel injection amount from the fuel injection valve according to the elapsed time from the start of the desorption, whereby the three-way catalyst is controlled. Of the air-fuel ratio at the entrance of the vehicle.
【0003】[0003]
【発明が解決しようとする課題】しかしながら、図3
(A)に示すような、三元触媒層をHC吸着材の上層に
コーティング等した所謂HC吸着触媒を用いて、冷機時
にHCをHC吸着材に吸着し、暖機完了後にHC吸着材
からHCを脱離すると共に、この脱離したHCを前記三
元触媒層で浄化するようにした場合には、以下のような
惧れがある。However, FIG.
As shown in (A), a so-called HC adsorption catalyst in which a three-way catalyst layer is coated on the upper layer of an HC adsorbent is used to adsorb HC to the HC adsorbent at the time of cooling, and after the warming-up is completed, the HC adsorbs from the HC adsorbent. When the desorbed HC is purified by the three-way catalyst layer, the following fears may be caused.
【0004】即ち、前記HC吸着材から脱離したHCを
前記三元触媒層で浄化する際において、HC吸着材から
脱離したHCが三元触媒層へ拡散する速度と、排気ガス
中の酸素(O2 )が三元触媒層に取り込まれる(吸着さ
れる)速度と、に差があるために、上記従来の空燃比制
御では、脱離したHCの酸化に必要なO2 量が三元触媒
層表面に十分に吸着させることができず、以って三元触
媒層表面におけるHC量とO 2 量とのバランスが崩れ、
HC吸着材から脱離したHCを良好に浄化できなくなる
惧れがあった。That is, HC desorbed from the HC adsorbent is
When purifying with the three-way catalyst layer, the HC adsorbent
The rate at which the desorbed HC diffuses into the three-way catalyst layer and the exhaust gas
Oxygen (OTwo) Is taken into the three-way catalyst layer (adsorbed
Speed) and the conventional air-fuel ratio
The O required for the oxidation of the desorbed HCTwoThree-way catalyst
Not fully adsorbed on the layer surface
HC content and O on the surface of the medium layer TwoThe balance with the quantity is lost,
HC desorbed from HC adsorbent cannot be purified well
There was fear.
【0005】本発明は、かかる実情に鑑みなされたもの
で、HC吸着触媒を用いた場合においても、脱離したH
Cを三元触媒層で良好に浄化できるようにした内燃機関
の空燃比制御装置を提供することを目的とする。[0005] The present invention has been made in view of such circumstances, and even when an HC adsorbing catalyst is used, the desorbed H is used.
It is an object of the present invention to provide an air-fuel ratio control device for an internal combustion engine in which C can be favorably purified by a three-way catalyst layer.
【0006】[0006]
【課題を解決するための手段】このため、請求項1に記
載の発明にかかる内燃機関の空燃比制御装置は、図1に
示すように、HC吸着材の上層に三元触媒層を備えて構
成されるHC吸着触媒を排気通路に介装した内燃機関の
空燃比制御装置であって、前記HC吸着材からのHCの
脱離中に、前記HC吸着触媒の出口部の排気空燃比が所
定量リーンになるように、内燃機関の吸入混合気の空燃
比を制御する空燃比制御手段を含んで構成するようにし
た。Therefore, an air-fuel ratio control apparatus for an internal combustion engine according to the first aspect of the present invention includes a three-way catalyst layer as an upper layer of an HC adsorbent as shown in FIG. An air-fuel ratio control device for an internal combustion engine having an HC adsorption catalyst arranged in an exhaust passage, wherein the exhaust air-fuel ratio at an outlet of the HC adsorption catalyst is adjusted during desorption of HC from the HC adsorbent. An air-fuel ratio control means for controlling the air-fuel ratio of the intake air-fuel mixture of the internal combustion engine so as to achieve a fixed amount of lean is provided.
【0007】かかる構成とすれば、HC吸着材の上層に
三元触媒層を備えて構成されるHC吸着触媒を用いた場
合において、HCの脱離中に、HC吸着材から脱離した
HCが三元触媒層へ拡散する速度と、排気ガス中の酸素
(O2 )が三元触媒層に取り込まれる(吸着される)速
度と、の差を考慮して、HC吸着触媒の出口部における
空燃比を所定量リーンに制御するようにしたので、脱離
したHCの酸化に必要なO2 を三元触媒層の表面により
多く吸着させることができ、以ってHC吸着材から脱離
したHCを良好に浄化することができることとなる。[0007] With this configuration, when the HC adsorbing catalyst having the three-way catalyst layer on the upper layer of the HC adsorbing material is used, the HC desorbed from the HC adsorbing material during the desorption of HC. In consideration of the difference between the speed of diffusion into the three-way catalyst layer and the speed of oxygen (O 2 ) in the exhaust gas being taken into (adsorbed into) the three-way catalyst layer, the air at the outlet of the HC adsorption catalyst is taken into account. since the ratio was set to be controlled to a predetermined amount lean, the O 2 required for the oxidation of HC desorbed can be adsorbed more on the surface of the three-way catalyst layer, desorbed from the HC adsorbent me than HC Can be satisfactorily purified.
【0008】つまり、従来のように、HCの脱離量だけ
三元触媒(層)入口部の空燃比をリーン化するようにし
た場合における惧れ、即ちHC吸着材から脱離したHC
が三元触媒層へ拡散する速度と、排気ガス中の酸素(O
2 )が三元触媒層に取り込まれる(吸着される)速度
と、の差により、脱離したHCの酸化に必要なO2 量が
三元触媒層表面に十分に吸着させることができず、以っ
て三元触媒層表面におけるHC量とO2 量とのバランス
が崩れ、HC吸着材から脱離したHCを良好に浄化でき
なくなると言った惧れ、を抑制することが可能となる。That is, there is a concern in the case where the air-fuel ratio at the inlet of the three-way catalyst (layer) is made lean by the amount of desorbed HC as in the prior art, that is, HC desorbed from the HC adsorbent.
The rate at which oxygen diffuses into the three-way catalyst layer and the oxygen (O
Due to the difference between the rate at which 2 ) is taken into (adsorbed to) the three-way catalyst layer, the amount of O 2 required for the oxidation of the desorbed HC cannot be sufficiently adsorbed on the surface of the three-way catalyst layer, Accordingly, it is possible to suppress the fear that the balance between the amount of HC and the amount of O 2 on the surface of the three-way catalyst layer is lost and the HC desorbed from the HC adsorbent cannot be sufficiently purified.
【0009】請求項2に記載の発明では、前記内燃機関
の吸入混合気の空燃比が、前記HC吸着触媒の出口部に
設けられた空燃比センサの検出値に基づいて、前記HC
吸着材からのHCの脱離中に、前記HC吸着触媒の出口
部の排気空燃比が所定量リーンになるように、フィード
バック制御されるように構成した。かかる構成によれ
ば、前記内燃機関の吸入混合気の空燃比を、前記HC吸
着材からのHCの脱離中に、前記HC吸着触媒の出口部
の排気空燃比が所定量リーンになるようにフィードバッ
ク制御することができるので、経時変化や外乱等があっ
ても、高精度に、脱離したHCの酸化に必要なO2 を三
元触媒層の表面に吸着させることができ、以ってHC吸
着材から脱離したHCを良好に浄化することができるこ
ととなる。According to the present invention, the air-fuel ratio of the intake air-fuel mixture of the internal combustion engine is determined based on a detection value of an air-fuel ratio sensor provided at an outlet of the HC adsorption catalyst.
During the desorption of HC from the adsorbent, feedback control is performed so that the exhaust air-fuel ratio at the outlet of the HC adsorption catalyst becomes lean by a predetermined amount. With this configuration, the air-fuel ratio of the intake air-fuel mixture of the internal combustion engine is adjusted so that the exhaust air-fuel ratio at the outlet of the HC adsorption catalyst becomes a predetermined amount during the desorption of HC from the HC adsorbent. Since feedback control can be performed, O 2 required for oxidation of the desorbed HC can be adsorbed on the surface of the three-way catalyst layer with high accuracy even if there is a change over time or disturbance. HC desorbed from the HC adsorbent can be satisfactorily purified.
【0010】請求項3に記載の発明では、前記内燃機関
の吸入混合気の空燃比が、前記HC吸着材からのHCの
脱離中に、前記HC吸着触媒の出口部の排気空燃比が所
定量リーンになるように、フィードフォワード制御され
るように構成した。かかる構成とすれば、比較的簡単な
構成で、脱離したHCの酸化に必要なO2を三元触媒層
の表面に吸着させることができ、以ってHC吸着材から
脱離したHCを良好に浄化することができることとな
る。なお、HC脱離開始直後は、フィードフォワード制
御を行ない、その後はフィードバック制御を行なわせる
構成とすることも可能である。According to the third aspect of the present invention, the air-fuel ratio of the intake air-fuel mixture of the internal combustion engine is such that the exhaust air-fuel ratio at the outlet of the HC adsorbing catalyst varies during the desorption of HC from the HC adsorbent. It was configured to be feed-forward controlled so as to achieve a quantitative lean. With such a configuration, O 2 required for the oxidation of the desorbed HC can be adsorbed on the surface of the three-way catalyst layer with a relatively simple configuration, whereby the HC desorbed from the HC adsorbent can be removed. Good purification can be achieved. It is also possible to adopt a configuration in which feedforward control is performed immediately after the start of HC desorption, and then feedback control is performed.
【0011】請求項4に記載の発明では、前記所定量
が、HC吸着触媒の温度に応じて設定されるように構成
した。つまり、HCの脱離濃度(速度)は、HC吸着触
媒の温度と共に高く(速く)なる特性があるので、HC
吸着触媒の温度に応じて、前記所定量を変化させるよう
にすれば、常に、脱離したHCの酸化に必要なO2 を三
元触媒層の表面に吸着させることができ、以ってHC吸
着材から脱離したHCを良好に浄化することができるこ
ととなる。[0011] In the invention according to claim 4, the predetermined amount is set in accordance with the temperature of the HC adsorption catalyst. That is, the desorption concentration (speed) of HC has a characteristic that it increases (increases) with the temperature of the HC adsorption catalyst.
Depending on the temperature of the adsorption catalyst, if to vary the predetermined amount, always, the O 2 required for the oxidation of HC desorbed can be adsorbed on the surface of the three-way catalyst layer, I than HC HC desorbed from the adsorbent can be satisfactorily purified.
【0012】請求項5に記載の発明では、前記HC吸着
触媒の温度を、内燃機関の運転状態に基づいて推定する
構成とした。かかる構成とすれば、前記HC吸着触媒の
温度を検出するためのセンサを省略することができるの
で、製品コストの低減を図ることができる。請求項6に
記載の発明では、前記HC吸着触媒の温度を、内燃機関
の燃料噴射量或いは吸入空気流量の積算値に基づいて推
定するようにした。[0012] In the invention described in claim 5, the temperature of the HC adsorption catalyst is estimated based on the operating state of the internal combustion engine. With such a configuration, a sensor for detecting the temperature of the HC adsorption catalyst can be omitted, so that product cost can be reduced. In the invention described in claim 6, the temperature of the HC adsorption catalyst is estimated based on the integrated value of the fuel injection amount or the intake air flow rate of the internal combustion engine.
【0013】かかる構成とすれば、前記HC吸着触媒の
温度を検出するためのセンサを省略することができるの
で、製品コストの低減を図ることができると共に、比較
的簡単な構成で高精度に、前記HC吸着触媒の温度を推
定することが可能となる。With this configuration, a sensor for detecting the temperature of the HC adsorption catalyst can be omitted, so that the product cost can be reduced, and a relatively simple configuration can be used with high accuracy. It is possible to estimate the temperature of the HC adsorption catalyst.
【0014】[0014]
【発明の効果】請求項1に記載の発明によれば、HC吸
着材の上層に三元触媒層を備えて構成されるHC吸着触
媒を用いた場合において、HCの脱離中に、HC吸着材
から脱離したHCが三元触媒層へ拡散する速度と、排気
ガス中の酸素が三元触媒層に取り込まれる(吸着され
る)速度と、の差を考慮して、HC吸着触媒の出口部に
おける空燃比を所定量リーンに制御するようにしたの
で、脱離したHCの酸化に必要なO2 を三元触媒層の表
面により多く吸着させることができ、以ってHC吸着材
から脱離したHCを良好に浄化することができる。According to the first aspect of the present invention, when an HC adsorbing catalyst having a three-way catalyst layer on the upper layer of the HC adsorbing material is used, the HC adsorbing is performed during the desorption of HC. In consideration of the difference between the rate at which HC desorbed from the material diffuses into the three-way catalyst layer and the rate at which oxygen in exhaust gas is taken in (adsorbed) into the three-way catalyst layer, the outlet of the HC adsorption catalyst is considered. since so as to control the air-fuel ratio to a predetermined amount lean in part, de-a O 2 required for the oxidation of HC desorbed can be adsorbed more on the surface of the three-way catalyst layer, from the HC adsorbent me than The separated HC can be satisfactorily purified.
【0015】つまり、従来のように、HCの脱離量だけ
三元触媒(層)入口部の空燃比をリーン化するようにし
た場合における惧れ、即ちHC吸着材から脱離したHC
が三元触媒層へ拡散する速度と、排気ガス中の酸素が三
元触媒層に取り込まれる(吸着される)速度と、の差に
より、脱離したHCの酸化に必要なO2 量が三元触媒層
表面に十分に吸着させることができず、以って三元触媒
層表面におけるHC量とO2 量とのバランスが崩れ、H
C吸着材から脱離したHCを良好に浄化できなくなると
言った惧れ、を抑制することができる。That is, there is a concern in the case where the air-fuel ratio at the inlet of the three-way catalyst (layer) is made lean by the amount of desorbed HC as in the prior art, that is, HC desorbed from the HC adsorbent.
The difference between the rate at which oxygen diffuses into the three-way catalyst layer and the rate at which oxygen in the exhaust gas is taken into (adsorbed to) the three-way catalyst layer reduces the amount of O 2 necessary for the oxidation of the desorbed HC by three. Cannot be sufficiently adsorbed on the surface of the three-way catalyst layer, and thus the balance between the amount of HC and the amount of O 2 on the surface of the three-way catalyst layer is lost.
The concern that HC desorbed from the C adsorbent cannot be satisfactorily purified can be suppressed.
【0016】請求項2に記載の発明によれば、経時変化
や外乱等があっても、高精度に、脱離したHCの酸化に
必要なO2 を三元触媒層の表面に吸着させることがで
き、以ってHC吸着材から脱離したHCを良好に浄化す
ることができることとなる。請求項3に記載の発明によ
れば、比較的簡単な構成で、脱離したHCの酸化に必要
なO2 を三元触媒層の表面に吸着させることができ、以
ってHC吸着材から脱離したHCを良好に浄化すること
ができることとなる。According to the second aspect of the present invention, O 2 required for the oxidation of the desorbed HC can be adsorbed on the surface of the three-way catalyst layer with high accuracy even if there is a temporal change or disturbance. Thus, HC desorbed from the HC adsorbent can be satisfactorily purified. According to the third aspect of the present invention, O 2 required for the oxidation of the desorbed HC can be adsorbed on the surface of the three-way catalyst layer with a relatively simple configuration, so that the HC adsorbent can be removed from the HC adsorbent. The desorbed HC can be satisfactorily purified.
【0017】請求項4に記載の発明によれば、HC吸着
触媒の温度に応じて、前記所定量を変化させるようにし
たので、常に、脱離したHCの酸化に必要なO2 を三元
触媒層の表面に吸着させることができ、以ってHC吸着
材から脱離したHCを良好に浄化することができること
となる。請求項5に記載の発明によれば、前記HC吸着
触媒の温度を検出するためのセンサを省略することがで
きるので、製品コストの低減を図ることができる。According to the fourth aspect of the present invention, the predetermined amount is changed in accordance with the temperature of the HC adsorption catalyst, so that O 2 necessary for oxidizing the desorbed HC is always ternary. HC can be adsorbed on the surface of the catalyst layer, so that HC desorbed from the HC adsorbent can be satisfactorily purified. According to the fifth aspect of the present invention, since a sensor for detecting the temperature of the HC adsorption catalyst can be omitted, product cost can be reduced.
【0018】請求項6に記載の発明によれば、製品コス
トの低減を図ることができると共に、比較的簡単な構成
で高精度に、前記HC吸着触媒の温度を推定することが
可能となる。According to the invention described in claim 6, the cost of the product can be reduced, and the temperature of the HC adsorption catalyst can be estimated with high accuracy with a relatively simple configuration.
【0019】[0019]
【発明の実施の形態】以下に、本発明の一実施形態を、
添付の図面に基づいて説明する。本発明の一実施形態の
構成を示す図2において、機関11の吸気通路12には
吸入空気流量Qaを検出するエアフローメータ13及び
アクセルペダルと連動して吸入空気流量Qaを制御する
スロットル弁14が設けられ、下流のマニホールド部分
には気筒毎に電磁式の燃料噴射弁15が設けられてい
る。なお、燃料噴射弁15を各気筒の燃焼室に臨ませる
構成とし、本実施形態にかかる内燃機関を所謂筒内直接
噴射式内燃機関とすることもできる。DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below.
Description will be given based on the attached drawings. 2, an air flow meter 13 for detecting an intake air flow rate Qa and a throttle valve 14 for controlling the intake air flow rate Qa in conjunction with an accelerator pedal are provided in an intake passage 12 of an engine 11 in FIG. An electromagnetic fuel injection valve 15 is provided for each cylinder in the downstream manifold portion. The fuel injection valve 15 may be configured to face the combustion chamber of each cylinder, and the internal combustion engine according to the present embodiment may be a so-called direct injection type internal combustion engine.
【0020】かかる燃料噴射弁15は、後述するように
してコントロールユニット50において設定される駆動
パルス信号によって開弁駆動され、図示しない燃料ポン
プから圧送されてプレッシャレギュレータ(図示せず)
により所定圧力に制御された燃料を噴射供給する。な
お、機関11の冷却ジャケットに臨んで設けられ、冷却
ジャケット内の冷却水温度Twを検出する水温センサ1
6が設けられている。The fuel injection valve 15 is driven to open by a drive pulse signal set in the control unit 50 as described later, and is pressure-fed from a fuel pump (not shown) to pressure regulator (not shown).
Injects and supplies fuel controlled to a predetermined pressure. A water temperature sensor 1 is provided facing the cooling jacket of the engine 11 and detects a cooling water temperature Tw in the cooling jacket.
6 are provided.
【0021】一方、排気通路17にはマニホールド集合
部近傍に、排気中の特定成分(例えば、酸素)濃度を検
出することによって吸入混合気の空燃比のリッチ・リー
ンを検出する酸素センサ18が設けられ、その下流側
に、理論空燃比{λ=1、A/F(空気重量/燃料重
量)≒14.7}近傍において排気中のCO,HCの酸
化とNOX の還元を行って排気を浄化する排気浄化触媒
としての三元触媒(所謂マニ触媒)19が介装されてい
る。On the other hand, an oxygen sensor 18 is provided in the exhaust passage 17 near the manifold collecting portion to detect the concentration of a specific component (for example, oxygen) in the exhaust gas to detect the rich / lean air-fuel ratio of the intake air-fuel mixture. On the downstream side, in the vicinity of the stoichiometric air-fuel ratio {λ = 1, A / F (air weight / fuel weight) {14.7}, CO and HC in the exhaust gas are oxidized and NO x is reduced to reduce the exhaust gas. A three-way catalyst (so-called manifold catalyst) 19 as an exhaust gas purifying catalyst for purifying is interposed.
【0022】また、本実施形態では、三元触媒19の排
気下流側に、図3(A)に示すようなHC吸着材20A
の上層に三元触媒層(三元層)20Bをコーティング等
したHC吸着触媒20が介装されており、冷機時に排気
中のHCを前記HC吸着材20Aに吸着し{図3(B)
参照}、暖機完了後に前記HC吸着材20AからHCを
脱離すると共に脱離したHCを、前記三元触媒層20B
で浄化するようになっている{図3(C)参照}。In this embodiment, the HC adsorbent 20A as shown in FIG.
An HC adsorption catalyst 20 coated with a three-way catalyst layer (three-layer) 20B or the like is interposed in the upper layer, and adsorbs HC in the exhaust gas to the HC adsorbent 20A during cooling.
Reference II, after the warm-up is completed, the HC is desorbed from the HC adsorbent 20A and the desorbed HC is transferred to the three-way catalyst layer 20B.
(See FIG. 3 (C)).
【0023】前記HC吸着触媒20の出口部には、排気
中の特定成分(例えば、酸素)濃度を検出することによ
って吸入混合気の空燃比をリーン領域からリッチ領域ま
でリニアに検出することができる空燃比センサ21が設
けられている。また、図2で図示しないディストリビュ
ータには、クランク角センサ22が内蔵されており、コ
ントロールユニット50では、該クランク角センサ22
から機関回転と同期して出力されるクランク単位角信号
を一定時間カウントして、又は、クランク基準角信号の
周期を計測して機関回転速度Neを検出できるようにな
っている。At the outlet of the HC adsorption catalyst 20, the air-fuel ratio of the intake air-fuel mixture can be detected linearly from a lean region to a rich region by detecting the concentration of a specific component (eg, oxygen) in the exhaust gas. An air-fuel ratio sensor 21 is provided. The distributor (not shown in FIG. 2) has a built-in crank angle sensor 22.
The engine rotation speed Ne can be detected by counting a crank unit angle signal output in synchronization with the engine rotation for a certain period of time, or by measuring the cycle of the crank reference angle signal.
【0024】ところで、CPU,ROM,RAM,A/
D変換器及び入出力インタフェース等を含んで構成され
るマイクロコンピュータからなるコントロールユニット
50では、各種センサからの入力信号を受け、通常時
(非脱離時)には、概略以下のようにして、燃料噴射弁
15の噴射量(延いては空燃比)を制御する。即ち、エ
アフローメータ13からの電圧信号から求められる吸入
空気流量Qaと、クランク角センサ22からの信号から
求められる機関回転速度Neとから基本燃料噴射パルス
幅(燃料噴射量に相当)Tp=c×Qa/Ne(cは定
数)を演算すると共に、低水温時に強制的にリッチ側に
補正する水温補正係数Kwや、始動及び始動後増量補正
係数Kasや、空燃比フィードバック補正係数LAMD1
等により、最終的な有効燃料噴射パルス幅Te=Tp×
(1+Kw+Kas+・・・)×LAMD1+Tsを演算
する。Tsは、電圧補正分である。By the way, CPU, ROM, RAM, A /
The control unit 50 including a microcomputer including a D converter and an input / output interface receives input signals from various sensors, and in a normal state (at the time of non-desorption), as described below, The injection amount of the fuel injection valve 15 (and hence the air-fuel ratio) is controlled. That is, the basic fuel injection pulse width (corresponding to the fuel injection amount) Tp = c × from the intake air flow rate Qa obtained from the voltage signal from the air flow meter 13 and the engine rotation speed Ne obtained from the signal from the crank angle sensor 22. While calculating Qa / Ne (c is a constant), a water temperature correction coefficient Kw that forcibly corrects to a rich side at a low water temperature, a startup and post-start increase correction coefficient Kas, and an air-fuel ratio feedback correction coefficient LAMD1
The final effective fuel injection pulse width Te = Tp ×
(1 + Kw + Kas +...) × LAMD1 + Ts is calculated. Ts is a voltage correction amount.
【0025】そして、この有効燃料噴射パルス幅Teが
駆動パルス信号として前記燃料噴射弁15に送られて、
所定量に調量された燃料が噴射供給されることになる。
上記空燃比フィードバック補正係数LAMD1は、三元
触媒19の上流側に設けられた酸素センサ18のリッチ
・リーン反転出力に基づいて比例積分(PI)制御等に
より増減されるもので、これに基づきコントロールユニ
ット50では基本燃料パルス幅Tpを補正し、燃焼用混
合気の空燃比を目標空燃比(理論空燃比)近傍にフィー
ドバック制御するものである。The effective fuel injection pulse width Te is sent to the fuel injection valve 15 as a drive pulse signal.
Fuel adjusted to a predetermined amount is injected and supplied.
The air-fuel ratio feedback correction coefficient LAMD1 is increased or decreased by proportional integration (PI) control or the like based on the rich / lean inversion output of the oxygen sensor 18 provided on the upstream side of the three-way catalyst 19, and is controlled based on this. In the unit 50, the basic fuel pulse width Tp is corrected, and the air-fuel ratio of the combustion air-fuel mixture is feedback-controlled near the target air-fuel ratio (the stoichiometric air-fuel ratio).
【0026】ところで、前記HC吸着触媒20を用い
て、脱離したHCを、前記三元触媒層20Bで浄化する
場合には、HC吸着材20Aから脱離したHCが三元触
媒層20Bへ拡散する速度と、排気ガス中の酸素
(O2 )が三元触媒層20Bに取り込まれる(吸着され
る)速度と、に差があるため、従来のようにHC吸着触
媒20の入口部の空燃比をリーンに制御するだけでは、
脱離したHCの酸化に必要なO 2 量を三元触媒層20B
の表面に十分に吸着させることができず、以って三元触
媒層20Bの表面におけるHC量とO2 量とのバランス
が崩れ、HC吸着材20Aから脱離したHCを良好に浄
化できなくなる惧れがある{図3(C)参照}。By the way, using the HC adsorption catalyst 20,
Then, the desorbed HC is purified by the three-way catalyst layer 20B.
In this case, the HC desorbed from the HC adsorbent 20A is
The speed of diffusion into the medium layer 20B and the oxygen in the exhaust gas
(OTwo) Is taken into (adsorbed to) the three-way catalyst layer 20B.
Speed), there is a difference between the
By simply controlling the air-fuel ratio at the inlet of the medium 20 to lean,
O necessary for oxidation of desorbed HC TwoThe amount is three-way catalyst layer 20B
Can not be sufficiently adsorbed on the surface of
HC amount and O on the surface of the medium layer 20BTwoBalance with quantity
Has been disintegrated, and the HC desorbed from the HC adsorbent 20A is satisfactorily purified.
There is a risk that the system will not be able to be converted (see Fig. 3 (C)).
【0027】このため、本実施形態では、HC吸着材2
0Aから脱離したHCが三元触媒層20Bへ拡散する速
度と、排気ガス中の酸素(O2 )が三元触媒層20Bに
取り込まれる(吸着される)速度と、の差分を考慮し
て、空燃比を制御することで、三元触媒層20Bの表面
におけるHC量とO2 量とをバランスさせ、以ってHC
吸着材20Aから脱離したHCを良好に浄化できるよう
にしている。For this reason, in this embodiment, the HC adsorbent 2
The difference between the rate at which HC desorbed from 0A diffuses into the three-way catalyst layer 20B and the rate at which oxygen (O 2 ) in exhaust gas is taken in (adsorbed) into the three-way catalyst layer 20B is taken into account. By controlling the air-fuel ratio, the amount of HC and the amount of O 2 on the surface of the three-way catalyst layer 20B are balanced, whereby the HC
HC desorbed from the adsorbent 20A can be satisfactorily purified.
【0028】即ち、HCの脱離時には、本実施形態に係
るコントロールユニット50では、各種センサからの入
力信号を受け、図4に示すようなフローチャートを実行
して、燃料噴射弁15の噴射量(延いては空燃比)を制
御する。なお、以下に説明するように、本発明にかかる
空燃比制御手段としての機能は、コントロールユニット
50がソフトウェア的に備えるものである。また、図4
のフローチャートは、機関11の始動時毎に実行される
ものである。That is, when the HC is desorbed, the control unit 50 according to the present embodiment receives input signals from various sensors and executes a flowchart as shown in FIG. And thus the air-fuel ratio). Note that, as described below, the function as the air-fuel ratio control means according to the present invention is provided by the control unit 50 as software. FIG.
The flowchart of FIG. 5 is executed every time the engine 11 is started.
【0029】即ち、ステップ(図では、Sと記してあ
る。以下、同様)1では、冷却水温度Tw<コールド
(冷機)判定温度Aか否かを判定する。YESであれ
ば、コールド(冷機)時であるので、ステップ2へ進
む。NOであれば、通常運転時であるとして前述した通
常の空燃比制御を行なわせるべく、本フローを終了す
る。That is, in step (denoted by S in the figure, hereinafter the same), it is determined whether or not the cooling water temperature Tw <the cold (cooler) determination temperature A. If YES, the process proceeds to step 2 because it is a cold (cold) time. If the determination is NO, this flow is terminated in order to perform the normal air-fuel ratio control described above assuming that the normal operation is being performed.
【0030】ステップ2では、従来同様の手法によっ
て、基本燃料噴射量Tp(或いは吸入空気流量Qa)を
積算或いは加重平均して、HC吸着触媒20の温度Tc
を推定する。例えば、燃焼によって発生し排気を介して
HC吸着触媒20へ与えられた熱量{Tp(又はQa)
の積算値或いは加重平均値から算出できる}と、排気に
よりHC吸着触媒20から持ち去られる熱量{排気流量
(吸入空気流量Qa)等に相関する}などを考慮して、
触媒温度Tcを推定することができ、外気温度,水温T
w等を考慮すれば、より推定精度を向上できる。In step 2, the basic fuel injection amount Tp (or intake air flow rate Qa) is integrated or weighted average by a method similar to the conventional method, and the temperature Tc of the HC adsorption catalyst 20 is calculated.
Is estimated. For example, the amount of heat ΔTp (or Qa) generated by combustion and given to the HC adsorption catalyst 20 via exhaust gas
And the amount of heat removed from the HC adsorption catalyst 20 by the exhaust gas {correlated to the exhaust gas flow rate (intake air flow rate Qa)}, etc.
The catalyst temperature Tc can be estimated, and the outside air temperature and the water temperature T can be estimated.
Considering w and the like, the estimation accuracy can be further improved.
【0031】また、燃料噴射量Tp,機関回転速度Ne
から、その運転状態が継続された場合の平衡触媒温度を
推定し、その推定値と、その運転状態での運転継続時間
(或いは時定数)などと、に基づいて、現在の触媒温度
Tcを推定すること等もできる。なお、図2に示した触
媒温度センサ23を介して、直接、触媒温度Tcを検出
する構成とすることもできる。Further, the fuel injection amount Tp, the engine speed Ne,
From the above, the equilibrium catalyst temperature when the operation state is continued is estimated, and the current catalyst temperature Tc is estimated based on the estimated value and the operation continuation time (or time constant) in the operation state. And so on. Note that a configuration may be employed in which the catalyst temperature Tc is directly detected via the catalyst temperature sensor 23 shown in FIG.
【0032】ステップ3では、触媒温度Tc>HC脱離
開始温度T1であるか否かを判定する。YESであれ
ば、HC吸着触媒20の温度が上昇し、冷機時に吸着し
たHCが、HC吸着材20Aから脱離するので、HC吸
着材20Aから脱離したHCが三元触媒層20Bへ拡散
する速度と、排気ガス中の酸素(O2 )が三元触媒層2
0Bに取り込まれる(吸着される)速度と、の差分を考
慮した空燃比制御を実行すべく、ステップ4へ進む。一
方、NOであれば、ステップ2へリターンする。In step 3, it is determined whether or not the catalyst temperature Tc> HC desorption start temperature T1. If YES, the temperature of the HC adsorbing catalyst 20 rises, and the HC adsorbed at the time of cooling is desorbed from the HC adsorbent 20A, so that the HC desorbed from the HC adsorbent 20A diffuses to the three-way catalyst layer 20B. Velocity and oxygen (O 2 ) in exhaust gas are converted to three-way catalyst layer 2
The process proceeds to step 4 in order to execute the air-fuel ratio control in consideration of the difference between the speed taken in (absorbed) by 0B. On the other hand, if NO, the process returns to step 2.
【0033】ステップ4では、吸着材20AのHC吸着
量を演算する。なお、HC吸着量は、例えば、基本燃料
噴射量Tp(或いは吸入空気流量Qa)の積算値に、吸
着効率αを乗算(Tp積算値×α)することで推定演算
することができる。つづくステップ5では、目標空燃比
TFBYA(HC吸着触媒20の出口部における目標空
燃比であり、リーン側に設定される)を演算する。ここ
で、目標空燃比TFBYAは、以下の式により演算す
る。In step 4, the amount of HC adsorbed by the adsorbent 20A is calculated. The HC adsorption amount can be estimated and calculated by, for example, multiplying the integrated value of the basic fuel injection amount Tp (or the intake air flow rate Qa) by the adsorption efficiency α (Tp integrated value × α). In the next step 5, the target air-fuel ratio TFBYA (the target air-fuel ratio at the outlet of the HC adsorption catalyst 20, which is set to the lean side) is calculated. Here, the target air-fuel ratio TFBYA is calculated by the following equation.
【0034】即ち、 TFBYA=Tc×γ ここで、Tc;HC吸着触媒20の温度、γ;目標空燃
比係数 つまり、図5に示すように、HCの脱離濃度(速度)は
触媒温度Tcで決まる(触媒温度に略比例する)から、
これに目標空燃比係数γ{≒『酸素(O2 )が三元触媒
層20Bに取り込まれる速度』/『HCの脱離速度』}
を乗算すれば、触媒温度に応じてHCを良好に浄化する
のに必要な酸素量延いては目標空燃比TFBYA(空気
重量/燃料重量)を求めることができることとなる。な
お、図6に示すようなテーブル等を参照して、HC吸着
触媒20の温度Tcに応じて、目標空燃比TFBYAを
設定するようにすることもできる。That is, TFBYA = Tc × γ where Tc: temperature of the HC adsorption catalyst 20, γ: target air-fuel ratio coefficient That is, as shown in FIG. 5, the desorption concentration (speed) of HC depends on the catalyst temperature Tc. Determined (substantially proportional to the catalyst temperature)
The target air-fuel ratio coefficient γ {“the speed at which oxygen (O 2 ) is taken into the three-way catalyst layer 20B” / “the HC desorption speed”}
Is multiplied, it is possible to obtain a target air-fuel ratio TFBYA (air weight / fuel weight), that is, an amount of oxygen necessary for purifying HC properly according to the catalyst temperature. The target air-fuel ratio TFBYA may be set in accordance with the temperature Tc of the HC adsorption catalyst 20 with reference to a table as shown in FIG.
【0035】そして、コントロールユニット50では、
最終的な有効燃料噴射パルス幅Te=Tp×(1+Kw
+Kas+・・・)×1/TFBYA+Tsを演算し、こ
の有効燃料噴射パルス幅Teを駆動パルス信号として前
記燃料噴射弁15に送り、所定量に調量された燃料を噴
射供給することになる。ステップ6では、HC吸着触媒
20の出口部に設けた空燃比センサ21の検出空燃比に
基づき、HC吸着触媒20の出口部における空燃比が、
目標空燃比TFBYA(リーン側に設定される)になる
ように燃料噴射量をフィードバック制御する。Then, in the control unit 50,
Final effective fuel injection pulse width Te = Tp × (1 + Kw
+ Kas +...) × 1 / TFBYA + Ts, the effective fuel injection pulse width Te is sent to the fuel injection valve 15 as a drive pulse signal, and the fuel adjusted to a predetermined amount is injected and supplied. In step 6, based on the air-fuel ratio detected by the air-fuel ratio sensor 21 provided at the outlet of the HC adsorption catalyst 20, the air-fuel ratio at the outlet of the HC adsorption catalyst 20 is calculated as
The fuel injection amount is feedback-controlled so that the target air-fuel ratio becomes TFBYA (set to the lean side).
【0036】つまり、Te=Tp×(1+Kw+Kas+
・・・)×1/TFBYA×LAMD2+Tsを演算
し、この有効燃料噴射パルス幅Teを駆動パルス信号と
して前記燃料噴射弁15へ送り、HC吸着触媒20の出
口部における空燃比が、目標空燃比TFBYAとなるよ
うにフィードバック制御されることになる。なお、上記
空燃比フィードバック補正係数LAMD2は、HC吸着
触媒20の下流側に設けられた空燃比センサ21の空燃
比検出信号(空燃比に対してリニアな信号として出力さ
れる)に基づいて比例積分(PI)制御等により増減設
定されるものである。That is, Te = Tp × (1 + Kw + Kas +
..) × 1 / TFBYA × LAMD2 + Ts, the effective fuel injection pulse width Te is sent to the fuel injection valve 15 as a drive pulse signal, and the air-fuel ratio at the outlet of the HC adsorption catalyst 20 becomes the target air-fuel ratio TFBYA. The feedback control is performed so that The air-fuel ratio feedback correction coefficient LAMD2 is proportionally integrated based on an air-fuel ratio detection signal (output as a linear signal with respect to the air-fuel ratio) of an air-fuel ratio sensor 21 provided on the downstream side of the HC adsorption catalyst 20. (PI) It is set to increase or decrease by control or the like.
【0037】ステップ7では、吸着材20AのHC脱離
量を積算する。なお、HC脱離量は、例えば、以下の式
により推定演算することができる。 HC脱離量=Qa×Tc×β ここで、Qa;吸入空気流量、β;脱離量換算係数 つまり、図5に示すように、HCの脱離濃度(%、pp
m)は触媒温度で決まるので、Tc×βにより、触媒温
度に応じたHCの脱離濃度を算出することができ、ま
た、HCの脱離濃度に吸入空気流量Qa(l/min又
はg/min){排気流量(l/min又はg/mi
n)に相関する値である}を乗算すれば、HCの脱離量
を求めることができる。In step 7, the HC desorption amount of the adsorbent 20A is integrated. The HC desorption amount can be estimated and calculated by, for example, the following equation. HC desorption amount = Qa × Tc × β where Qa: intake air flow rate, β; desorption amount conversion coefficient That is, as shown in FIG. 5, the desorption concentration of HC (%, pp
m) is determined by the catalyst temperature, so that the desorption concentration of HC according to the catalyst temperature can be calculated from Tc × β, and the desorption concentration of HC can be calculated based on the intake air flow rate Qa (l / min or g / min) {exhaust flow rate (l / min or g / mi)
The desorption amount of HC can be obtained by multiplying n) by a value correlated with 相関.
【0038】そして、ステップ8では、ステップ7で求
めたHC脱離量の積算値と、HC吸着量と、を比較し、
HC脱離量の積算値≧HC吸着量であれば、HCの脱離
処理は完了したと判断して、通常(非脱離時)の空燃比
制御へ移行させる。一方、HC脱離量の積算値<HC吸
着量であれば、未だHCの脱離中であるので、本フロー
による空燃比制御を継続する必要があるので、HC脱離
量の積算値≧HC吸着量となるまで、ステップ5へリタ
ーンする。In step 8, the integrated value of the HC desorption amount obtained in step 7 is compared with the HC adsorption amount.
If the integrated value of the HC desorption amount ≧ the HC adsorption amount, it is determined that the HC desorption process has been completed, and the process shifts to the normal (non-desorption) air-fuel ratio control. On the other hand, if the integrated value of the HC desorption amount is smaller than the HC adsorption amount, the air is still being desorbed, and the air-fuel ratio control by this flow needs to be continued. The process returns to step 5 until the amount of adsorption is reached.
【0039】このように、本実施形態によれば、HC吸
着触媒20を用いた場合において、HCの脱離中に、H
C吸着材20Aから脱離したHCが三元触媒層20Bへ
拡散する速度と、排気ガス中の酸素(O2 )が三元触媒
層20Bに取り込まれる(吸着される)速度と、の差を
考慮して、HC吸着触媒20の出口部における空燃比
を、脱離したHCの酸化に必要なO2 量を三元触媒層2
0B表面に十分に吸着させることができる目標空燃比T
FBYA(リーン空燃比)に制御するようにしたので、
HC吸着材から脱離したHCを良好に浄化することがで
きることとなる。As described above, according to the present embodiment, when the HC adsorption catalyst 20 is used, during the desorption of HC, H
The difference between the rate at which HC desorbed from the C adsorbent 20A diffuses into the three-way catalyst layer 20B and the rate at which oxygen (O 2 ) in the exhaust gas is taken into (adsorbed to) the three-way catalyst layer 20B is determined. Considering the air-fuel ratio at the outlet of the HC adsorption catalyst 20, the amount of O 2 required for the oxidation of the desorbed HC is
Target air-fuel ratio T that can be sufficiently adsorbed on the 0B surface
Since it is controlled to FBYA (lean air-fuel ratio),
HC desorbed from the HC adsorbent can be satisfactorily purified.
【0040】なお、図4のフローチャートにおけるステ
ップ6を省略して、所謂オープン制御(フィードフォワ
ード制御)により、HC吸着触媒20の出口部における
空燃比を、目標空燃比TFBYA(リーン空燃比)に制
御することもできる。この場合は、空燃比センサ21を
省略してもよい。ところで、従来のようにHC吸着材の
下流側にHC吸着材とは別個独立に三元触媒を設けたも
のでは、HCの脱離中には三元触媒の入口部の空燃比を
HCの脱離量に見合ってリーン化する(この場合、三元
触媒の出口部の空燃比は理論空燃比近傍に制御される)
のに対し、本発明は、HC吸着触媒20を用いた場合
に、HCの脱離中には、HC吸着材20Aから脱離した
HCが三元触媒層20Bへ拡散する速度より、排気ガス
中の酸素(O2 )が三元触媒層20Bに取り込まれる
(吸着される)速度が遅いことを考慮して、その分、H
C吸着触媒20の出口部の空燃比をリーンにして、三元
触媒層20Bの表面におけるHC量とO2 量とをバラン
スさせ、HC吸着材20Aから脱離したHCを良好に浄
化できるようにしたものである。Step 6 in the flowchart of FIG. 4 is omitted, and the air-fuel ratio at the outlet of the HC adsorption catalyst 20 is controlled to the target air-fuel ratio TFBYA (lean air-fuel ratio) by so-called open control (feedforward control). You can also. In this case, the air-fuel ratio sensor 21 may be omitted. By the way, when a three-way catalyst is provided independently of the HC adsorbent on the downstream side of the HC adsorbent as in the related art, the air-fuel ratio at the inlet of the three-way catalyst is changed during HC desorption. Lean according to the amount of separation (in this case, the air-fuel ratio at the outlet of the three-way catalyst is controlled near the stoichiometric air-fuel ratio)
On the other hand, according to the present invention, when the HC adsorption catalyst 20 is used, during the desorption of HC, the rate at which HC desorbed from the HC adsorbent 20A is diffused into the three-way catalyst layer 20B is reduced. In consideration of the low rate at which oxygen (O 2 ) is taken up (adsorbed) into the three-way catalyst layer 20B, H
The air-fuel ratio at the outlet of the C adsorption catalyst 20 is made lean to balance the amount of HC and the amount of O 2 on the surface of the three-way catalyst layer 20B so that the HC desorbed from the HC adsorbent 20A can be satisfactorily purified. It was done.
【0041】言い換えると、本発明は、HC吸着触媒2
0を用いた場合のHC脱離中において、三元触媒層20
Bの表面におけるHC量とO2 量とをバランスさせるた
めに、HC吸着触媒20の出口部の空燃比をリーン側に
制御することを、その本質とするものである。つまり、
本実施形態は、脱離したHCをより効果的に浄化するた
めに、目標空燃比TFBYAを最適値に設定する場合に
ついて説明したものであり、本発明は、これに限定され
るものではなく、HCの脱離中においてHC吸着触媒2
0の出口部の空燃比をリーン側に制御する構成とするだ
けでも、従来に対して脱離したHCを良好に浄化するこ
とができるものであり、従って、HCの脱離中において
HC吸着触媒20の出口部の空燃比をリーン側に制御す
るものは、本発明の範囲に含まれるものである。In other words, the present invention provides the HC adsorption catalyst 2
0 during the HC desorption, the three-way catalyst layer 20
In order to balance the amount of HC and the amount of O 2 on the surface of B, the essential point is to control the air-fuel ratio at the outlet of the HC adsorption catalyst 20 to the lean side. That is,
The present embodiment describes a case where the target air-fuel ratio TFBYA is set to an optimal value in order to more effectively purify the desorbed HC, and the present invention is not limited to this. HC adsorption catalyst 2 during HC desorption
By simply controlling the air-fuel ratio at the outlet of 0 to the lean side, it is possible to satisfactorily purify the desorbed HC as compared with the prior art. The one that controls the air-fuel ratio at the outlet of 20 to the lean side is included in the scope of the present invention.
【図1】本発明の構成を示すブロック図FIG. 1 is a block diagram showing the configuration of the present invention.
【図2】本発明の一実施形態にかかるシステム構成図FIG. 2 is a system configuration diagram according to an embodiment of the present invention;
【図3】(A)は、HC吸着触媒の構造を説明する図。
(B)は、冷機時(コールド時)におけるHC吸着触媒
の機能を説明する図。(C)は、暖機時(ホット時)に
おけるHC吸着触媒の機能を説明する図。FIG. 3A is a diagram illustrating a structure of an HC adsorption catalyst.
(B) is a diagram for explaining the function of the HC adsorption catalyst at the time of cold (at the time of cold). (C) is a diagram for explaining the function of the HC adsorption catalyst during warm-up (hot).
【図4】同上実施形態における空燃比制御を説明するた
めのフローチャート。FIG. 4 is a flowchart for explaining air-fuel ratio control in the embodiment.
【図5】脱離HC濃度と、HC吸着触媒温度と、の関係
を説明するためのタイミングチャート。FIG. 5 is a timing chart for explaining the relationship between the desorbed HC concentration and the HC adsorption catalyst temperature.
【図6】脱離HC濃度と、HC吸着触媒温度と、の関係
を示すテーブルの一例。FIG. 6 is an example of a table showing a relationship between a desorbed HC concentration and an HC adsorption catalyst temperature.
11 内燃機関 12 吸気通路 13 エアフローメータ 14 スロットル弁 15 燃料噴射弁 17 排気通路 18 酸素センサ 19 三元触媒(マニ触媒) 20 HC吸着触媒 21 空燃比センサ(リニアセンサ) 22 クランク角センサ 50 コントロールユニット 11 Internal combustion engine 12 Intake passage 13 Air flow meter 14 Throttle valve 15 Fuel injection valve 17 Exhaust passage 18 Oxygen sensor 19 Three-way catalyst (manifold catalyst) 20 HC adsorption catalyst 21 Air-fuel ratio sensor (linear sensor) 22 Crank angle sensor 50 Control unit
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 FI F02D 45/00 312 F02D 45/00 312R 364 364N 366 366F ──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. 6 Identification code FI F02D 45/00 312 F02D 45/00 312R 364 364N 366 366F
Claims (6)
成されるHC吸着触媒を排気通路に介装した内燃機関の
空燃比制御装置であって、 前記HC吸着材からのHCの脱離中に、前記HC吸着触
媒の出口部の排気空燃比が所定量リーンになるように、
内燃機関の吸入混合気の空燃比を制御する空燃比制御手
段を含んで構成したことを特徴とする内燃機関の空燃比
制御装置。1. An air-fuel ratio control device for an internal combustion engine having an HC adsorbent, which is provided with a three-way catalyst layer above a HC adsorbent, interposed in an exhaust passage, comprising: During desorption, the exhaust air-fuel ratio at the outlet of the HC adsorption catalyst becomes lean by a predetermined amount,
An air-fuel ratio control device for an internal combustion engine, comprising air-fuel ratio control means for controlling an air-fuel ratio of an intake air-fuel mixture of the internal combustion engine.
記HC吸着触媒の出口部に設けられた空燃比センサの検
出値に基づいて、前記HC吸着材からのHCの脱離中
に、前記HC吸着触媒の出口部の排気空燃比が所定量リ
ーンになるように、フィードバック制御されることを特
徴とする請求項1に記載の内燃機関の空燃比制御装置。2. An air-fuel ratio of an intake air-fuel mixture of the internal combustion engine, based on a detection value of an air-fuel ratio sensor provided at an outlet of the HC adsorption catalyst, during the desorption of HC from the HC adsorbent. 2. The air-fuel ratio control device for an internal combustion engine according to claim 1, wherein feedback control is performed such that the exhaust air-fuel ratio at the outlet of the HC adsorption catalyst becomes lean by a predetermined amount.
記HC吸着材からのHCの脱離中に、前記HC吸着触媒
の出口部の排気空燃比が所定量リーンになるように、フ
ィードフォワード制御されることを特徴とする請求項1
又は請求項2に記載の内燃機関の空燃比制御装置。3. An air-fuel ratio of an intake air-fuel mixture of the internal combustion engine is set so that an exhaust air-fuel ratio at an outlet of the HC adsorbing catalyst becomes lean by a predetermined amount during desorption of HC from the HC adsorbing material. 2. The feedforward control is performed.
Or an air-fuel ratio control device for an internal combustion engine according to claim 2.
て設定されることを特徴とする請求項1〜請求項3の何
れか1つに記載の内燃機関の空燃比制御装置。4. The air-fuel ratio control device for an internal combustion engine according to claim 1, wherein the predetermined amount is set according to the temperature of the HC adsorption catalyst.
転状態に基づいて推定されることを特徴とする請求項1
〜請求項4の何れか1つに記載の内燃機関の空燃比制御
装置。5. The system according to claim 1, wherein the temperature of the HC adsorption catalyst is estimated based on an operation state of the internal combustion engine.
An air-fuel ratio control device for an internal combustion engine according to any one of claims 1 to 4.
料噴射量或いは吸入空気流量の積算値に基づいて推定さ
れることを特徴とする請求項1〜請求項5の何れか1つ
に記載の内燃機関の空燃比制御装置。6. The method according to claim 1, wherein the temperature of the HC adsorption catalyst is estimated based on an integrated value of a fuel injection amount or an intake air flow rate of the internal combustion engine. An air-fuel ratio control device for an internal combustion engine according to the above.
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JP24640997A JP3610740B2 (en) | 1997-09-11 | 1997-09-11 | Air-fuel ratio control device for internal combustion engine |
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US6560959B2 (en) | 1999-12-06 | 2003-05-13 | Denso Corporation | Exhaust gas purification apparatus of internal combustion engine |
US6732503B2 (en) | 2001-10-01 | 2004-05-11 | Toyota Jidosha Kabushiki Kaisha | Air/fuel ratio controller for internal combustion engine |
US6976355B2 (en) | 2001-02-27 | 2005-12-20 | Mazda Motor Corporation | Exhaust-gas cleaning device for engine |
WO2007123011A1 (en) * | 2006-04-10 | 2007-11-01 | Isuzu Motors Limited | Exhaust gas purification method and exhaust gas purification system |
JP2010071217A (en) * | 2008-09-19 | 2010-04-02 | Nissan Motor Co Ltd | Exhaust emission control device for engine |
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1997
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US6560959B2 (en) | 1999-12-06 | 2003-05-13 | Denso Corporation | Exhaust gas purification apparatus of internal combustion engine |
US6976355B2 (en) | 2001-02-27 | 2005-12-20 | Mazda Motor Corporation | Exhaust-gas cleaning device for engine |
US6732503B2 (en) | 2001-10-01 | 2004-05-11 | Toyota Jidosha Kabushiki Kaisha | Air/fuel ratio controller for internal combustion engine |
WO2007123011A1 (en) * | 2006-04-10 | 2007-11-01 | Isuzu Motors Limited | Exhaust gas purification method and exhaust gas purification system |
US8056321B2 (en) | 2006-04-10 | 2011-11-15 | Isuzu Motors Limited | Exhaust gas purification method and exhaust gas purification system |
JP2010071217A (en) * | 2008-09-19 | 2010-04-02 | Nissan Motor Co Ltd | Exhaust emission control device for engine |
CN113464304A (en) * | 2020-03-31 | 2021-10-01 | 本田技研工业株式会社 | Temperature acquisition device for internal combustion engine |
JP2021161965A (en) * | 2020-03-31 | 2021-10-11 | 本田技研工業株式会社 | Temperature acquiring device of internal combustion engine |
US11326530B2 (en) | 2020-03-31 | 2022-05-10 | Honda Motor Co., Ltd. | Temperature acquisition apparatus for internal combustion engine |
CN113464304B (en) * | 2020-03-31 | 2023-03-14 | 本田技研工业株式会社 | Temperature acquisition device for internal combustion engine |
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