JPH06200736A - Exhaust emission control device for engine - Google Patents
Exhaust emission control device for engineInfo
- Publication number
- JPH06200736A JPH06200736A JP123393A JP123393A JPH06200736A JP H06200736 A JPH06200736 A JP H06200736A JP 123393 A JP123393 A JP 123393A JP 123393 A JP123393 A JP 123393A JP H06200736 A JPH06200736 A JP H06200736A
- Authority
- JP
- Japan
- Prior art keywords
- temperature
- exhaust gas
- adsorbing member
- gas
- exhaust
- 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
Links
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
- 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
Landscapes
- Exhaust Gas After Treatment (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、エンジンから排出され
る排気ガス中に含まれる炭化水素ＨＣ等の未燃ガスを浄
化するエンジンの排気浄化装置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine exhaust purification system for purifying unburned gas such as hydrocarbon HC contained in exhaust gas discharged from an engine.
【０００２】[0002]
【従来の技術】エンジンから排出される排気ガス中に
は、有害成分である炭化水素ＨＣ等の未燃ガスが含まれ
ており、この未燃ガスを触媒により上記排気ガスから除
去することは一般に行なわれているが、この触媒は活性
温度以上になるまで働かない。2. Description of the Related Art Exhaust gas discharged from an engine contains unburned gas such as hydrocarbon HC, which is a harmful component, and it is generally removed from the exhaust gas by a catalyst. Although done, this catalyst does not work until above its activation temperature.
【０００３】そこで、排気通路における触媒の上流に、
エンジン始動直後に多量に排出される炭化水素ＨＣを吸
着し、所定温度（約２００℃）以上になると上記吸着し
た炭化水素ＨＣを離脱する未燃ガス吸着材を配設した排
気浄化装置が提案されている（実開昭６０−１９０９２
３号公報）。Therefore, upstream of the catalyst in the exhaust passage,
An exhaust gas purification device is proposed which has an unburned gas adsorbent that adsorbs a large amount of hydrocarbons HC discharged immediately after the engine is started and releases the adsorbed hydrocarbons HC at a predetermined temperature (about 200 ° C.) or higher. It is (actual development Sho 60-19092
3 gazette).
【０００４】一方、上記排気通路の途中に、エンジン始
動後の冷間時に触媒に電力を供給して加熱することによ
り、触媒が上記活性温度に達するまでの時間を短縮して
触媒による炭化水素ＨＣの浄化を速やかに開始させる排
気浄化装置が提案されている（実開昭６３−６７６０９
号公報）。On the other hand, in the middle of the exhaust passage, electric power is supplied to the catalyst to heat it during the cold period after the engine is started, so that the time required for the catalyst to reach the activation temperature is shortened and hydrocarbon HC generated by the catalyst is reduced. An exhaust gas purification device that promptly starts the purification of the exhaust gas has been proposed (Shokai 63-67609).
Issue).
【０００５】[0005]
【発明が解決しようとする課題】ところが、実開昭６０
−１９０９２３号公報記載の排気浄化装置による場合、
通常、未燃ガス吸着材が炭化水素ＨＣを離脱し始める温
度（約２００℃）は、触媒の活性温度（約３００℃）よ
りも低い。従って、上記未燃ガス吸着材の温度が上記所
定温度に達して炭化水素ＨＣが離脱し始めたときには、
上記触媒は未だ炭化水素ＨＣを浄化する活性温度に達し
ていない。このため、炭化水素ＨＣが排気ガス中から除
去されないまま大気に排出されることになる。DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the case of the exhaust emission control device described in Japanese Patent Publication No. 190923,
Usually, the temperature (about 200 ° C.) at which the unburned gas adsorbent starts desorbing hydrocarbons HC is lower than the catalyst activation temperature (about 300 ° C.). Therefore, when the temperature of the unburned gas adsorbent reaches the predetermined temperature and the hydrocarbons HC start to desorb,
The catalyst has not yet reached the activation temperature for purifying hydrocarbons HC. Therefore, the hydrocarbon HC is discharged to the atmosphere without being removed from the exhaust gas.
【０００６】一方、実開昭６３−６７６０９号公報記載
の排気浄化装置による場合には、エンジン始動直後の低
温状態から触媒が活性温度になるまで排気ガスを加熱す
る必要があり、上記加熱期間中の触媒への電力供給によ
るバッテリー及びオルタネータに対する負担が大きく、
バッテリーの容量を大きくしたり、オルタネータの発電
量を増やしたりする必要がある。このため、燃費、エン
ジン制御、車載レイアウト等への影響が極めて大きいと
いった問題がある。また、上記加熱が開始されてから触
媒が活性温度になるまでの立ち上がり期間に炭化水素Ｈ
Ｃが排気ガス中から除去されないまま大気に排出され
る。On the other hand, in the case of the exhaust gas purifying apparatus described in Japanese Utility Model Laid-Open No. 63-67609, it is necessary to heat the exhaust gas from a low temperature state immediately after engine start up to the activation temperature of the catalyst, and during the above heating period. The burden on the battery and alternator due to the power supply to the catalyst of
It is necessary to increase the capacity of the battery and increase the amount of power generated by the alternator. Therefore, there is a problem that the influence on fuel consumption, engine control, in-vehicle layout, etc. is extremely large. Further, during the rising period from the start of the heating to the activation temperature of the catalyst, the hydrocarbon H
C is discharged into the atmosphere without being removed from the exhaust gas.
【０００７】本発明は、上記の事情に鑑み、消費電力が
少なく、且つ、確実に未燃ガスを浄化することができる
エンジンの排気浄化装置を提供することを目的とする。In view of the above circumstances, it is an object of the present invention to provide an engine exhaust gas purification device that consumes less power and can reliably purify unburned gas.
【０００８】[0008]
【課題を解決するための手段】本発明は上記目的を達成
するために、エンジンからの排気ガスを大気に排出する
排気通路の途中に、第１の温度未満で上記排気ガス中の
未燃ガスを吸着し、第１の温度以上で上記吸着した未燃
ガスを離脱する未燃ガス吸着部材と、この未燃ガス吸着
部材の下流側に設けられ、上記第１の温度より高い第２
の温度以上で活性化して上記未燃ガスを浄化する触媒と
を有するエンジンの排気浄化装置において、上記未燃ガ
ス吸着部材の温度及び排気ガスの温度に関連する温度を
検出する温度検出手段と、上記未燃ガス吸着部材と上記
触媒との間に設けられ、上記排気ガスを上記第２の温度
以上に加熱する排気ガス加熱手段と、少なくとも上記未
燃ガス吸着部材が上記第１の温度以上であって排気ガス
が上記第２の温度未満のときに上記加熱手段を作動させ
る作動手段とを備えたものである。In order to achieve the above object, the present invention provides an unburned gas in the exhaust gas below a first temperature in the middle of an exhaust passage for discharging exhaust gas from an engine to the atmosphere. And an unburned gas adsorbing member that adsorbs the adsorbed unburned gas and desorbs the adsorbed unburned gas at a temperature equal to or higher than a first temperature, and a second temperature higher than the first temperature provided downstream of the unburned gas adsorbing member.
In an exhaust gas purification apparatus for an engine having a catalyst that purifies the unburned gas by activating at a temperature equal to or higher than the temperature, temperature detection means for detecting a temperature related to the temperature of the unburned gas adsorbing member and the temperature of the exhaust gas, Exhaust gas heating means provided between the unburned gas adsorbing member and the catalyst for heating the exhaust gas to the second temperature or higher, and at least the unburned gas adsorbing member having the first temperature or higher. And an operating means for operating the heating means when the exhaust gas is below the second temperature.
【０００９】また、上記排気ガス加熱手段は、上記未燃
ガスを浄化する触媒機能を有するとともに、通電により
排気ガスの温度上昇を促進する電気加熱式触媒により形
成されていることが好ましい。It is preferable that the exhaust gas heating means has a catalytic function for purifying the unburned gas and is formed of an electrically heated catalyst that promotes a temperature rise of the exhaust gas by energization.
【００１０】さらに、上記未燃ガス吸着部材の上流側
に、上記排気通路に２次エアーを供給する２次エアー供
給手段を設けたことが好ましい。Further, it is preferable to provide a secondary air supply means for supplying secondary air to the exhaust passage on the upstream side of the unburned gas adsorption member.
【００１１】また、上記未燃ガス吸着部材が上記第１の
温度に達する時点と上記触媒が上記第２の温度に達する
時点とが略同時点となるように上記未燃ガス吸着部材及
び上記触媒を構成したことが好ましい。The unburned gas adsorbing member and the catalyst are arranged so that the time when the unburnt gas adsorbing member reaches the first temperature and the time when the catalyst reaches the second temperature are substantially the same. Is preferably configured.
【００１２】さらに、上記未燃ガス吸着部材の比熱を上
記触媒の比熱より大きくしたことが好ましい。Further, it is preferable that the specific heat of the unburned gas adsorbing member is made larger than the specific heat of the catalyst.
【００１３】[0013]
【作用】上記の構成によると、エンジン始動後の排気ガ
スの温度が低く、未燃ガス吸着部材の温度が第１の温度
未満となるときには、未燃ガス吸着部材により排気ガス
中の未燃ガスが吸着され、排気ガスの温度が上昇して未
燃ガス吸着部材の温度が第１の温度以上になると、上記
吸着した未燃ガスが未燃ガス吸着部材から離脱される。
そして、未燃ガス吸着部材の温度及び排気ガスの温度に
関連する温度が検出され、少なくとも未燃ガス吸着部材
が上記第１の温度以上であって排気ガスが上記第２の温
度未満のときには、排気ガス加熱手段が作動されて排気
ガスが上記第２の温度以上に加熱され、触媒により排気
ガス中の未燃ガスが浄化される。一方、排気ガスが上記
第２の温度以上になると、排気ガス加熱手段が停止さ
れ、排気ガス自体の温度で温められた触媒により排気ガ
ス中の未燃ガスが浄化されることにより、少ない加熱期
間で排気ガス中の未燃ガスを浄化することができる。According to the above construction, when the temperature of the exhaust gas is low after the engine is started and the temperature of the unburned gas adsorbing member is lower than the first temperature, the unburned gas adsorbing member causes the unburned gas in the exhaust gas to be unburned. Are adsorbed, the temperature of the exhaust gas rises, and when the temperature of the unburned gas adsorption member becomes equal to or higher than the first temperature, the adsorbed unburned gas is separated from the unburned gas adsorption member.
Then, the temperature related to the temperature of the unburned gas adsorbing member and the temperature of the exhaust gas is detected, and at least when the unburned gas adsorbing member is at the first temperature or higher and the exhaust gas is lower than the second temperature, The exhaust gas heating means is operated to heat the exhaust gas to the second temperature or higher, and the catalyst purifies the unburned gas in the exhaust gas. On the other hand, when the exhaust gas reaches the second temperature or higher, the exhaust gas heating means is stopped, and the unheated gas in the exhaust gas is purified by the catalyst warmed at the temperature of the exhaust gas itself, thereby reducing the heating period. Thus, unburned gas in the exhaust gas can be purified.
【００１４】また、電気加熱式触媒に通電されることに
より排気ガスの温度上昇が促進され、未燃ガスが浄化さ
れることにより、触媒の浄化に対する負担が減り、触媒
の小型化が図れる。Further, by energizing the electrically heated catalyst, the temperature rise of the exhaust gas is promoted and the unburned gas is purified, so that the burden on the purification of the catalyst is reduced and the catalyst can be downsized.
【００１５】さらに、未燃ガス吸着部材の上流側の排気
通路に２次エアーが供給されることにより、未燃ガス吸
着部材が冷却されて排気ガスの加熱期間を短くすること
ができる。Further, by supplying the secondary air to the exhaust passage on the upstream side of the unburned gas adsorbing member, the unburned gas adsorbing member is cooled and the heating period of the exhaust gas can be shortened.
【００１６】また、未燃ガス吸着部材が第１の温度に達
する時点と触媒が第２の温度に達する時点とが略同時点
となることによっても、排気ガスの加熱期間を短くする
ことができる。Also, the heating period of the exhaust gas can be shortened by making the time point when the unburned gas adsorbing member reaches the first temperature and the time point when the catalyst reaches the second temperature substantially at the same time. .
【００１７】さらに、未燃ガス吸着部材の比熱が触媒の
比熱より大きく設定されたことによって、未燃ガス吸着
部材が第１の温度に達する時点と触媒が第２の温度に達
する時点とを略同時点にして排気ガスの加熱期間を短く
することができる。Further, since the specific heat of the unburned gas adsorbing member is set to be larger than the specific heat of the catalyst, the time when the unburned gas adsorbing member reaches the first temperature and the time when the catalyst reaches the second temperature are substantially omitted. At the same time, the heating period of the exhaust gas can be shortened.
【００１８】[0018]
【実施例】本発明の実施例を図面に基づいて説明する。
図１は本発明に係るエンジンの排気浄化装置の第１実施
例を示している。なお、未燃ガスとして炭化水素ＨＣを
例に説明する。エンジン１は、各シリンダの燃焼室の上
部を形成するとともに、バルブ機構、吸気ポート及び排
気ポート等が配設されたシリンダヘッド１１と、ピスト
ンを収納するシリンダを配列したシリンダブロック１２
と、潤滑油が貯蔵されるオイルパン１３とを有してい
る。上記シリンダヘッド１１の排気ポートには、排気ガ
スを大気に排出する排気通路２が接続され、この排気通
路２の途中には、排気ガス中に含まれている有害成分で
ある炭化水素ＨＣを除去すべく、上流側から順番に未燃
ガス吸着部材となるＨＣ吸着部材３と、排気ガス加熱手
段となる電気加熱式触媒コンバータ４と、主触媒コンバ
ータ５とが配設されている。Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a first embodiment of an engine exhaust gas purification apparatus according to the present invention. Note that hydrocarbon HC will be described as an example of the unburned gas. The engine 1 forms an upper part of a combustion chamber of each cylinder, a cylinder head 11 in which a valve mechanism, an intake port, an exhaust port, and the like are arranged, and a cylinder block 12 in which cylinders accommodating pistons are arranged.
And an oil pan 13 in which lubricating oil is stored. The exhaust port of the cylinder head 11 is connected to an exhaust passage 2 for exhausting exhaust gas to the atmosphere, and in the middle of the exhaust passage 2, hydrocarbons HC which are harmful components contained in the exhaust gas are removed. Therefore, an HC adsorbing member 3 that serves as an unburned gas adsorbing member, an electrically heated catalytic converter 4 that serves as exhaust gas heating means, and a main catalytic converter 5 are arranged in this order from the upstream side.
【００１９】ＨＣ吸着部材３は、比較的比熱の大きいセ
ラミック担体に炭化水素ＨＣを脱着する吸着剤を配設し
たものである。そして、ＨＣ吸着部材３は、その温度が
第１の温度（約２００℃）未満のときには排気ガス中に
含まれている炭化水素ＨＣを吸着し、第１の温度以上に
なったときには上記吸着した炭化水素ＨＣを離脱させる
ようになっている。The HC adsorbing member 3 comprises a ceramic carrier having a relatively high specific heat and an adsorbent for desorbing hydrocarbons HC. Then, the HC adsorbing member 3 adsorbs the hydrocarbon HC contained in the exhaust gas when the temperature is lower than the first temperature (about 200 ° C.), and adsorbs the hydrocarbon HC when the temperature is higher than the first temperature. It is designed to release hydrocarbons HC.
【００２０】電気加熱式触媒コンバータ４は、通電可能
な担体に電源７から電流が供給されることにより発熱す
るもので、排気ガス及び担体に配設した触媒を加熱する
ようになっている。電源７は、バッテリー、オルタネー
タ等からなるものである。また、電源７から電気加熱式
触媒コンバータ４への電流供給ライン上には、電流のオ
ン、オフ制御を行なう制御部８が接続されている。この
制御部８は、ＨＣ吸着部材３に配設された温度センサ６
によりＨＣ吸着部材３の温度を検出し、この温度に基づ
いて上記電流のオン、オフ制御を行なうようになってい
る。すなわち、制御部８は、温度センサ６の温度検出結
果に基づいてＨＣ吸着部材３の温度が上記第１の温度以
上であって、排気ガスの温度が触媒の活性温度である第
２の温度（約３００℃）未満かどうかを判別し、少なく
ともＨＣ吸着部材３の温度が上記第１の温度以上であっ
て、排気ガスの温度が上記第２の温度未満のときにオン
して電源７から電気加熱式触媒コンバータ４へ電流を供
給させるようになっている。なお、制御部８は、上記Ｈ
Ｃ吸着部材３の温度及び比熱に基づいて排気ガスの温度
を判別するようになっている。また、制御部８は、ＨＣ
吸着部材３の温度が上記第１の温度より若干低いときか
らオンしてもよく、さらに排気ガスの温度が上記第２の
温度より若干高いときまでオンしていてもよい。The electrically heated catalytic converter 4 generates heat when a current is supplied from a power source 7 to a carrier which can be energized, and heats the exhaust gas and the catalyst arranged on the carrier. The power source 7 is composed of a battery, an alternator and the like. Further, on the current supply line from the power supply 7 to the electrically heated catalytic converter 4, a control unit 8 for controlling on / off of current is connected. The control unit 8 includes a temperature sensor 6 arranged on the HC adsorption member 3.
The temperature of the HC adsorbing member 3 is detected by the above, and the on / off control of the current is performed based on this temperature. That is, the control unit 8 determines that the temperature of the HC adsorbing member 3 is equal to or higher than the first temperature based on the temperature detection result of the temperature sensor 6 and the temperature of the exhaust gas is the second temperature (which is the activation temperature of the catalyst). If the temperature of the HC adsorbing member 3 is at least the first temperature and the temperature of the exhaust gas is less than the second temperature, the power is turned on and the power is supplied from the power source 7. An electric current is supplied to the heating type catalytic converter 4. The control unit 8 controls the above H
The temperature of the exhaust gas is determined based on the temperature and the specific heat of the C adsorption member 3. Further, the control unit 8 controls the HC
The adsorption member 3 may be turned on when the temperature is slightly lower than the first temperature, and may be turned on until the temperature of the exhaust gas is slightly higher than the second temperature.
【００２１】主触媒コンバータ５は、上記ＨＣ吸着部材
３より比熱の小さいメタル担体に炭化水素ＨＣを浄化す
る触媒を配設したものである。そして、主触媒コンバー
タ５は、排気ガスによって温められて上記第２の温度
（活性温度）以上となったときに活性化し、上記排気ガ
ス中の炭化水素ＨＣを酸化させて浄化するようになって
いる。The main catalytic converter 5 comprises a metal carrier having a specific heat smaller than that of the HC adsorbing member 3 and a catalyst for purifying hydrocarbon HC. Then, the main catalytic converter 5 is activated when it is warmed by the exhaust gas and becomes equal to or higher than the second temperature (activation temperature), and the hydrocarbon HC in the exhaust gas is oxidized and purified. There is.
【００２２】次に、上記ＨＣ吸着部材３と電気加熱式触
媒コンバータ４と主触媒コンバータ５との作用について
図２を用いて説明する。なお、図２の実線ＡはＨＣ吸着
部材３による排気ガスから炭化水素ＨＣを除去する割合
（除去率）を示し、実線Ｂは電気加熱式触媒コンバータ
４及び主触媒コンバータ５による炭化水素ＨＣの除去率
を示している。また、図２の二点鎖線Ｃは電気加熱式触
媒コンバータ４による排気ガスの加熱が行なわれないと
した場合の主触媒コンバータ５による炭化水素ＨＣの除
去率を示している。Next, the operation of the HC adsorbing member 3, the electrically heated catalytic converter 4 and the main catalytic converter 5 will be described with reference to FIG. A solid line A in FIG. 2 indicates a ratio (removal rate) of removing hydrocarbon HC from the exhaust gas by the HC adsorbing member 3, and a solid line B indicates removal of hydrocarbon HC by the electrically heated catalytic converter 4 and the main catalytic converter 5. Shows the rate. A chain double-dashed line C in FIG. 2 shows the removal rate of hydrocarbons HC by the main catalytic converter 5 when the electrically heated catalytic converter 4 does not heat the exhaust gas.
【００２３】エンジン始動後の排気ガスの温度が低いと
きには、実線Ａに示すように、ＨＣ吸着部材３によって
排気ガス中の炭化水素ＨＣが吸着されてほぼ１００％除
去される。そして、エンジンから排出された排気ガスに
よりＨＣ吸着部材３の温度が第１の温度（約２００℃）
になるｔ１時点で、ＨＣ吸着部材３に吸着されていた炭
化水素ＨＣが離脱し、排気ガスとともに電気加熱式触媒
コンバータ４へ運ばれる。一方、上記ｔ１時点でＨＣ吸
着部材３の温度が第１の温度になることにより制御部８
がオンして、電流が電源７から電気加熱式触媒コンバー
タ４へ供給され、電気加熱式触媒コンバータ４が発熱し
て排気ガスが加熱される。この加熱により排気ガスは第
２の温度（約３００℃）以上に温められ、この加熱され
た排気ガスにより電気加熱式触媒コンバータ４及び主触
媒コンバータ５の触媒の温度が上昇して上記第２の温度
に達する。これにより、電気加熱式触媒コンバータ４及
び主触媒コンバータ５の触媒が活性化し、排気ガス中の
炭化水素ＨＣが電気加熱式触媒コンバータ４及び主触媒
コンバータ５の触媒によって浄化され、実線Ｂに示すよ
うに、排気ガス中から炭化水素ＨＣが高率で除去され
る。When the temperature of the exhaust gas after starting the engine is low, as shown by the solid line A, the hydrocarbon HC in the exhaust gas is adsorbed by the HC adsorbing member 3 and removed almost 100%. The temperature of the HC adsorbing member 3 is the first temperature (about 200 ° C.) due to the exhaust gas discharged from the engine.
At time t1, the hydrocarbon HC adsorbed by the HC adsorbing member 3 is released and is carried to the electrically heated catalytic converter 4 together with the exhaust gas. On the other hand, when the temperature of the HC adsorbing member 3 reaches the first temperature at the time t1, the control unit 8
Is turned on, current is supplied from the power supply 7 to the electrically heated catalytic converter 4, the electrically heated catalytic converter 4 generates heat, and the exhaust gas is heated. By this heating, the exhaust gas is warmed to a second temperature (about 300 ° C.) or higher, and the heated exhaust gas raises the temperatures of the catalysts of the electrically heated catalytic converter 4 and the main catalytic converter 5 to increase the temperature of the second catalytic converter. Reach the temperature. As a result, the catalysts of the electrically heated catalytic converter 4 and the main catalytic converter 5 are activated, and the hydrocarbons HC in the exhaust gas are purified by the catalysts of the electrically heated catalytic converter 4 and the main catalytic converter 5, as shown by the solid line B. Moreover, the hydrocarbon HC is removed from the exhaust gas at a high rate.
【００２４】この後、エンジンから排出された排気ガス
の温度が上昇して第２の温度以上になると、制御部８が
オフになって電気加熱式触媒コンバータ４への電流が遮
断され、排気ガスへの加熱が停止する。一方、排気ガス
自体の温度により、電気加熱式触媒コンバータ４及び主
触媒コンバータ５の触媒は引き続き上記第２の温度以上
となり、これにより活性化される。従って、排気ガス中
の炭化水素ＨＣが電気加熱式触媒コンバータ４及び主触
媒コンバータ５により引き続き浄化される。After this, when the temperature of the exhaust gas discharged from the engine rises and becomes equal to or higher than the second temperature, the control unit 8 is turned off and the electric current to the electrically heated catalytic converter 4 is cut off, and the exhaust gas is exhausted. To stop heating. On the other hand, due to the temperature of the exhaust gas itself, the catalysts of the electrically heated catalytic converter 4 and the main catalytic converter 5 continue to reach the second temperature or higher, and are activated thereby. Therefore, the hydrocarbon HC in the exhaust gas is continuously purified by the electrically heated catalytic converter 4 and the main catalytic converter 5.
【００２５】このように、エンジン始動後の排気ガスの
温度が低いときには、排気ガス中の炭化水素ＨＣをＨＣ
吸着部材３に吸着させ、ＨＣ吸着部材３の温度が炭化水
素ＨＣの離脱が始まる第１の温度に達すると、電気加熱
式触媒コンバータ４によって排気ガスを第２の温度以上
に加熱して触媒を活性化し、これにより排気ガス中の炭
化水素ＨＣを浄化するので、図２の二点鎖線Ｃに示す電
気加熱式触媒コンバータ４による排気ガスの加熱が行な
われないとした場合のように、触媒が活性温度に上昇す
るまでの間（ｔ１時点からｔ２時点までの期間）に炭化
水素ＨＣが排気ガス中から余り除去されない状態で大気
に排出されることが防止される。As described above, when the temperature of the exhaust gas after the engine is started is low, the hydrocarbon HC in the exhaust gas is reduced to HC.
When it is adsorbed by the adsorbing member 3 and the temperature of the HC adsorbing member 3 reaches the first temperature at which hydrocarbon HC desorption starts, the electrically heated catalytic converter 4 heats the exhaust gas to a temperature equal to or higher than the second temperature to cause the catalyst. Since the hydrocarbons HC in the exhaust gas are activated and thus purified, the catalyst is removed as if the exhaust gas was not heated by the electrically heated catalytic converter 4 shown by the chain double-dashed line C in FIG. It is possible to prevent the hydrocarbon HC from being exhausted to the atmosphere in a state where it is not substantially removed from the exhaust gas until the temperature rises to the activation temperature (the period from time t1 to time t2).
【００２６】また、ＨＣ吸着部材３の温度が第１の温度
に達してから排気ガスが第２の温度になるまでの期間の
み電気加熱式触媒コンバータ４によって排気ガスを加熱
するので、上述した実開昭６３−６７６０９号公報記載
の排気浄化装置のようにエンジン始動直後から加熱する
必要がなく、電気加熱式触媒コンバータ４への供給電力
を低減することができる。しかも、加熱開始時点では、
排気ガスにより電気加熱式触媒コンバータ４自体も温め
られているので、第２の温度との温度差分だけ加熱すれ
ばよく、電気加熱式触媒コンバータ４への供給電力をさ
らに低減することができる。Further, since the exhaust gas is heated by the electrically heated catalytic converter 4 only during the period from when the temperature of the HC adsorbing member 3 reaches the first temperature to when the exhaust gas reaches the second temperature, the above-mentioned actual operation is performed. It is not necessary to heat the engine immediately after starting the engine unlike the exhaust gas purification apparatus disclosed in Japanese Patent Laid-Open No. 63-67609, and the electric power supplied to the electrically heated catalytic converter 4 can be reduced. Moreover, at the start of heating,
Since the electrically heated catalytic converter 4 itself is also warmed by the exhaust gas, only the temperature difference from the second temperature needs to be heated, and the electric power supplied to the electrically heated catalytic converter 4 can be further reduced.
【００２７】また、ＨＣ吸着部材３の比熱を主触媒コン
バータ５の比熱よりも大きくしたので、ＨＣ吸着部材３
の温度上昇に比して主触媒コンバータ５の温度上昇が速
くなり、これと電気加熱式触媒コンバータ４による加熱
とによってＨＣ吸着部材３の温度がエンジンから排出さ
れる排気ガスによって第１の温度になる時点と、主触媒
コンバータ５の温度がエンジンから排出される排気ガス
によって第２の温度になる時点とをほぼ同時点とするこ
とができ、電気加熱式触媒コンバータ４への供給電力を
より低減することができる。Since the specific heat of the HC adsorbing member 3 is made larger than that of the main catalytic converter 5, the HC adsorbing member 3 is
The temperature rise of the main catalytic converter 5 becomes faster than the temperature rise of the main catalytic converter 5, and the temperature of the HC adsorbing member 3 is brought to the first temperature by the exhaust gas discharged from the engine due to this and the heating by the electric heating type catalytic converter 4. And the temperature at which the temperature of the main catalytic converter 5 reaches the second temperature due to the exhaust gas discharged from the engine can be substantially the same point, and the electric power supplied to the electrically heated catalytic converter 4 can be further reduced. can do.
【００２８】続いて、本発明に係るエンジンの排気浄化
装置の第２実施例を図３及び図４を用いて説明する。こ
の実施例では、排気通路２の途中であってＨＣ吸着部材
３の上流側に２次エアー供給通路１０を介して２次エア
ー供給手段となるエアーポンプ９が接続されている。な
お、図３において、図１と同一符号が付されたものは同
一機能を果たすものである。また、図４の実線ＤはＨＣ
吸着部材３による炭化水素ＨＣの除去率を示し、実線Ｅ
は電気加熱式触媒コンバータ４及び主触媒コンバータ５
による炭化水素ＨＣの除去率を示している。さらに、図
４の二点鎖線Ａ，Ｂは２次エアーを供給しないとした場
合のＨＣ吸着部材３と主触媒コンバータ５（電気加熱式
触媒コンバータ４）との炭化水素ＨＣの除去率を示して
いる。Next, a second embodiment of the engine exhaust gas purification apparatus according to the present invention will be described with reference to FIGS. 3 and 4. In this embodiment, an air pump 9 serving as a secondary air supply means is connected to an upstream side of the HC adsorbing member 3 in the middle of the exhaust passage 2 via a secondary air supply passage 10. In FIG. 3, the same reference numerals as those in FIG. 1 have the same functions. Also, the solid line D in FIG.
The removal rate of hydrocarbons HC by the adsorption member 3 is shown, and the solid line E
Is an electrically heated catalytic converter 4 and a main catalytic converter 5
Shows the removal rate of hydrocarbons HC by. Further, two-dot chain lines A and B in FIG. 4 show the hydrocarbon HC removal rates of the HC adsorbing member 3 and the main catalytic converter 5 (electrically heated catalytic converter 4) when the secondary air is not supplied. There is.
【００２９】このエアーポンプ９は、外気を２次エアー
として排気通路２へ供給するものである。これにより、
排気通路２には、排気ガスより温度の低い外気が供給さ
れ、ＨＣ吸着部材３が冷却される。従って、ＨＣ吸着部
材３の温度上昇が遅くなり、図４の実線Ｄに示すよう
に、ＨＣ吸着部材３の温度が第１の温度になって炭化水
素ＨＣが離脱される時点が２次エアーを排気通路２へ供
給しないとした場合（図４の二点鎖線Ａ）に比して遅く
なる。これにより、電気加熱式触媒コンバータ４へ電流
を供給して排気ガスを加熱する時期を２次エアーを排気
通路２へ供給しないとした場合（図４の二点鎖線Ｂ）に
比して遅らせることができ、電気加熱式触媒コンバータ
４への供給電力をより低減することができる。The air pump 9 supplies the outside air to the exhaust passage 2 as secondary air. This allows
Outside air having a temperature lower than that of the exhaust gas is supplied to the exhaust passage 2, and the HC adsorbing member 3 is cooled. Therefore, the temperature rise of the HC adsorbing member 3 slows down, and as shown by the solid line D in FIG. 4, when the temperature of the HC adsorbing member 3 becomes the first temperature and the hydrocarbon HC is desorbed, the secondary air is discharged. It is delayed as compared with the case where the exhaust passage 2 is not supplied (two-dot chain line A in FIG. 4). As a result, the timing of supplying the electric current to the electrically heated catalytic converter 4 to heat the exhaust gas is delayed as compared with the case where the secondary air is not supplied to the exhaust passage 2 (two-dot chain line B in FIG. 4). Therefore, the electric power supplied to the electrically heated catalytic converter 4 can be further reduced.
【００３０】なお、２次エアーの供給位置から主触媒コ
ンバータ５までは離れているため、２次エアーの供給に
よって主触媒コンバータ５が冷却されることはない。ま
た、２次エアーは電気加熱式触媒コンバータ４によって
加熱されて主触媒コンバータ５へ送られるので、主触媒
コンバータ５へ外気を直接導いて炭化水素ＨＣを酸化さ
せる場合に比して酸化を促進することができ、炭化水素
ＨＣの浄化力を向上させることができる。Since the secondary air supply position is separated from the main catalytic converter 5, the secondary air supply does not cool the main catalytic converter 5. Further, since the secondary air is heated by the electrically heated catalytic converter 4 and sent to the main catalytic converter 5, the oxidation is promoted as compared with the case where the outside air is directly guided to the main catalytic converter 5 to oxidize the hydrocarbon HC. Therefore, the purification power of hydrocarbons HC can be improved.
【００３１】なお、上記実施例では、ＨＣ吸着部材３の
比熱と主触媒コンバータ５の比熱とを調整して、ＨＣ吸
着部材３の温度が第１の温度になる時点と主触媒コンバ
ータ５の温度が第２の温度になる時点とを略同時期とな
るようにしたが、上記比熱の調整に代えてＨＣ吸着部材
３及び主触媒コンバータ５の熱容量を調整することで、
ＨＣ吸着部材３の温度が第１の温度になる時点と主触媒
コンバータ５の温度が第２の温度になる時点とを略同時
期となるようにしてもよい。In the above embodiment, the specific heat of the HC adsorbing member 3 and the specific heat of the main catalytic converter 5 are adjusted so that the temperature of the HC adsorbing member 3 becomes the first temperature and the temperature of the main catalytic converter 5. The time when the temperature reaches the second temperature is set to be approximately the same time. However, by adjusting the heat capacities of the HC adsorbing member 3 and the main catalytic converter 5 instead of adjusting the specific heat,
The time at which the temperature of the HC adsorbing member 3 reaches the first temperature and the time at which the temperature of the main catalytic converter 5 reaches the second temperature may be approximately the same time.
【００３２】また、本発明の排気浄化装置において浄化
される未燃ガスは炭化水素ＨＣに限らず、一酸化炭素Ｃ
Ｏ等にも有効に適用される。The unburned gas purified by the exhaust gas purifying apparatus of the present invention is not limited to hydrocarbon HC but carbon monoxide C
It is effectively applied to O and the like.
【００３３】[0033]
【発明の効果】本発明は、未燃ガス吸着部材の温度が第
１の温度未満のときには未燃ガス吸着部材により排気ガ
ス中の未燃ガスを吸着し、未燃ガス吸着部材の温度が第
１の温度以上になると未燃ガスが未燃ガス吸着部材から
離脱し、少なくとも未燃ガス吸着部材が第１の温度以上
であって排気ガスが第２の温度未満であると排気ガス加
熱手段により排気ガスが第２の温度以上に加熱され、触
媒により排気ガス中の未燃ガスが浄化されるので、未燃
ガスを確実に浄化することができるとともに、加熱期間
を短くして加熱のための電力消費を少なくすることがで
きる。According to the present invention, when the temperature of the unburned gas adsorbing member is lower than the first temperature, the unburned gas adsorbing member adsorbs the unburned gas in the exhaust gas so that the temperature of the unburned gas adsorbing member is When the temperature becomes equal to or higher than 1, the unburned gas is separated from the unburned gas adsorbing member, and at least the unburnt gas adsorbing member has a temperature equal to or higher than the first temperature and the exhaust gas has a temperature lower than the second temperature. Since the exhaust gas is heated to the second temperature or higher and the unburned gas in the exhaust gas is purified by the catalyst, the unburned gas can be reliably purified, and the heating period is shortened for heating. Power consumption can be reduced.
【００３４】また、排気ガス加熱手段を電気加熱式触媒
により形成すると、触媒の負担を軽減して触媒の小型化
を図ることができる。Further, if the exhaust gas heating means is formed of an electrically heated catalyst, the burden on the catalyst can be reduced and the catalyst can be miniaturized.
【００３５】さらに、未燃ガス吸着部材の上流側の排気
通路に２次エアーを供給すると、２次エアーにより未燃
ガス吸着部材が冷却され、未燃ガス吸着部材が第１の温
度以上となる時期を遅らせることができ、排気ガスの加
熱期間を短くすることができる。Further, when the secondary air is supplied to the exhaust passage on the upstream side of the unburned gas adsorbing member, the unburned gas adsorbing member is cooled by the secondary air and the unburned gas adsorbing member is heated to the first temperature or higher. The timing can be delayed and the exhaust gas heating period can be shortened.
【００３６】また、未燃ガス吸着部材が第１の温度に達
する時点と触媒が第２の温度に達する時点とが略同時点
となると、排気ガスの加熱期間をより短くすることがで
きる。Further, when the time point when the unburned gas adsorbing member reaches the first temperature and the time point when the catalyst reaches the second temperature become substantially the same point, the heating period of the exhaust gas can be further shortened.
【図１】本発明に係るエンジンの排気浄化装置の第１実
施例を示す概略図である。FIG. 1 is a schematic diagram showing a first embodiment of an engine exhaust gas purification apparatus according to the present invention.
【図２】第１実施例の作用を説明するタイミングチャー
トである。FIG. 2 is a timing chart illustrating the operation of the first embodiment.
【図３】本発明に係るエンジンの排気浄化装置の第２実
施例を示す概略図である。FIG. 3 is a schematic view showing a second embodiment of the engine exhaust gas purification apparatus according to the present invention.
【図４】第２実施例の作用を説明するタイミングチャー
トである。FIG. 4 is a timing chart illustrating the operation of the second embodiment.
１ エンジン ２ 排気通路 ３ ＨＣ吸着部材 ４ 電気加熱式触媒コンバータ ５ 主触媒コンバータ ６ 温度センサ ７ 電源 ８ 制御部 ９ エアーポンプ １０ ２次エアー供給通路 1 Engine 2 Exhaust Passage 3 HC Adsorption Member 4 Electric Heating Type Catalytic Converter 5 Main Catalytic Converter 6 Temperature Sensor 7 Power Supply 8 Control Unit 9 Air Pump 10 Secondary Air Supply Passage
───────────────────────────────────────────────────── 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 3/24 Ｌ 3/32 Ｄ Ｆ０２Ｄ 45/00 ３１４ Ｒ 7536−3Ｇ ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 5 Identification code Internal reference number FI Technical display location F01N 3/24 L 3/32 D F02D 45/00 314 R 7536-3G
Claims (5)
る排気通路の途中に、第１の温度未満で上記排気ガス中
の未燃ガスを吸着し、第１の温度以上で上記吸着した未
燃ガスを離脱する未燃ガス吸着部材と、この未燃ガス吸
着部材の下流側に設けられ、上記第１の温度より高い第
２の温度以上で活性化して上記未燃ガスを浄化する触媒
とを有するエンジンの排気浄化装置において、上記未燃
ガス吸着部材の温度及び排気ガスの温度に関連する温度
を検出する温度検出手段と、上記未燃ガス吸着部材と上
記触媒との間に設けられ、上記排気ガスを上記第２の温
度以上に加熱する排気ガス加熱手段と、少なくとも上記
未燃ガス吸着部材が上記第１の温度以上であって排気ガ
スが上記第２の温度未満のときに上記加熱手段を作動さ
せる作動手段とを備えたことを特徴とするエンジンの排
気浄化装置。1. An unburned gas in the exhaust gas below a first temperature is adsorbed in the middle of an exhaust passage for exhausting exhaust gas from an engine to the atmosphere, and the adsorbed unburned gas above a first temperature. An unburned gas adsorbing member that releases gas and a catalyst that is provided on the downstream side of the unburned gas adsorbing member and that is activated at a second temperature or higher higher than the first temperature to purify the unburned gas are provided. In an engine exhaust emission control device having, a temperature detecting means for detecting a temperature related to the temperature of the unburned gas adsorbing member and a temperature of exhaust gas, and provided between the unburned gas adsorbing member and the catalyst, Exhaust gas heating means for heating the exhaust gas to the second temperature or higher, and the heating means when at least the unburned gas adsorbing member is at the first temperature or higher and the exhaust gas is lower than the second temperature. And an operating means for operating Exhaust gas purification device for engines characterized by the above.
を浄化する触媒機能を有するとともに、通電により排気
ガスの温度上昇を促進する電気加熱式触媒により形成さ
れていることを特徴とする請求項１記載のエンジンの排
気浄化装置。2. The exhaust gas heating means has a catalytic function for purifying the unburned gas, and is formed of an electrically heated catalyst for promoting a temperature rise of the exhaust gas by energization. Item 1. An engine exhaust emission control device according to item 1.
において、上記未燃ガス吸着部材の上流側に、上記排気
通路に２次エアーを供給する２次エアー供給手段を設け
たことを特徴とするエンジンの排気浄化装置。3. The engine exhaust gas purifying apparatus according to claim 1, further comprising a secondary air supply means for supplying secondary air to the exhaust passage upstream of the unburned gas adsorbing member. Exhaust purification device for engine.
に達する時点と上記触媒が上記第２の温度に達する時点
とが略同時点となるように上記未燃ガス吸着部材及び上
記触媒を構成したことを特徴とする請求項１記載のエン
ジンの排気浄化装置。4. The unburned gas adsorbing member and the catalyst so that the time when the unburned gas adsorbing member reaches the first temperature and the time when the catalyst reaches the second temperature are substantially the same time. The exhaust gas purification device for an engine according to claim 1, wherein
の比熱より大きくしたことを特徴とする請求項４記載の
エンジンの排気浄化装置。5. The exhaust gas purifying apparatus for an engine according to claim 4, wherein the specific heat of the unburned gas adsorbing member is larger than the specific heat of the catalyst.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP123393A JPH06200736A (en) | 1993-01-07 | 1993-01-07 | Exhaust emission control device for engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP123393A JPH06200736A (en) | 1993-01-07 | 1993-01-07 | Exhaust emission control device for engine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH06200736A true JPH06200736A (en) | 1994-07-19 |
Family
ID=11495754
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP123393A Pending JPH06200736A (en) | 1993-01-07 | 1993-01-07 | Exhaust emission control device for engine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06200736A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5979157A (en) * | 1996-08-15 | 1999-11-09 | Toyota Jidosha Kabushiki Kaisha | Method and a device for purifying exhaust gas of an internal combustion engine |
| JP2008261295A (en) * | 2007-04-13 | 2008-10-30 | Toyota Motor Corp | Exhaust emission control device of internal combustion engine |
-
1993
- 1993-01-07 JP JP123393A patent/JPH06200736A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5979157A (en) * | 1996-08-15 | 1999-11-09 | Toyota Jidosha Kabushiki Kaisha | Method and a device for purifying exhaust gas of an internal combustion engine |
| JP2008261295A (en) * | 2007-04-13 | 2008-10-30 | Toyota Motor Corp | Exhaust emission control device of internal combustion engine |
| WO2008129907A1 (en) * | 2007-04-13 | 2008-10-30 | Toyota Jidosha Kabushiki Kaisha | Exhaust emission control device for internal combustion engine |
| JP4710865B2 (en) * | 2007-04-13 | 2011-06-29 | トヨタ自動車株式会社 | Exhaust gas purification device for internal combustion engine |
| US8327622B2 (en) | 2007-04-13 | 2012-12-11 | Toyota Jidosha Kabushiki Kaisha | Exhaust gas purifying apparatus for internal combustion engine |
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