JPH021473Y2 - - Google Patents
Info
- Publication number
- JPH021473Y2 JPH021473Y2 JP1982159086U JP15908682U JPH021473Y2 JP H021473 Y2 JPH021473 Y2 JP H021473Y2 JP 1982159086 U JP1982159086 U JP 1982159086U JP 15908682 U JP15908682 U JP 15908682U JP H021473 Y2 JPH021473 Y2 JP H021473Y2
- Authority
- JP
- Japan
- Prior art keywords
- air
- exhaust gas
- fuel ratio
- temperature
- 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.)
- Expired
Links
Landscapes
- Exhaust Gas After Treatment (AREA)
- Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
Description
【考案の詳細な説明】
〔産業上の利用分野〕
本考案は、内燃機関の排気ガス中に含まれる窒
素酸化物等の不純物を三元触媒により浄化する排
気ガス浄化装置に関するものである。[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an exhaust gas purification device that uses a three-way catalyst to purify impurities such as nitrogen oxides contained in the exhaust gas of an internal combustion engine.
この種の排気ガス浄化装置は、三元触媒が理論
空燃比付近の狭い範囲でのみ高い浄化効率をあげ
るものであるため、エンジンに補正空気を供給し
て空燃比を調整する機構が設けられる。特に中型
車あるいは大型車に搭載される排気ガス浄化装置
の多くは、燃料消費率を小さくするとともに触媒
の浄化効率および車両の運転性を向上させるた
め、特開昭56−66415号公報にみられるように、
エンジンの吸気系および排気系の双方に補正空気
を供給して、三元触媒のために排気ガスを理論空
燃比にするように構成されている。
In this type of exhaust gas purification device, since the three-way catalyst achieves high purification efficiency only in a narrow range around the stoichiometric air-fuel ratio, a mechanism is provided for supplying correction air to the engine to adjust the air-fuel ratio. In particular, many of the exhaust gas purification devices installed in medium-sized or large-sized cars reduce the fuel consumption rate and improve the purification efficiency of the catalyst and the drivability of the vehicle. like,
It is configured to supply correction air to both the intake system and the exhaust system of the engine to bring the exhaust gas to a stoichiometric air-fuel ratio for the three-way catalyst.
このような構成の排気ガス浄化装置を有するエ
ンジンにおいては、燃焼室内に供給される混合気
が理論空燃比よりも濃いため、燃焼室から出てき
た排気ガスに二次空気を供給すると、触媒の活性
状態の温度が高くなる。ところがこの温度が高く
なりすぎると、三元触媒が劣化しやすくなつて耐
久性上好ましくなく、また触媒の近傍にあるゴム
部品等が損傷する等の熱害を生じる。
In an engine with an exhaust gas purification device configured in this way, the air-fuel mixture supplied into the combustion chamber is richer than the stoichiometric air-fuel ratio, so if secondary air is supplied to the exhaust gas coming out of the combustion chamber, the catalyst The temperature in the active state increases. However, if this temperature becomes too high, the three-way catalyst tends to deteriorate, which is not desirable in terms of durability, and also causes heat damage such as damage to rubber parts etc. near the catalyst.
本考案はこのような従来技術の問題点に鑑み、
触媒の活性状態における温度が過度に高くなるの
を防止しながら、三元触媒が常に本来の浄化能力
を発揮することのできる排気ガス浄化装置を得る
ことを目的としてなされたものである。 The present invention was developed in view of the problems of the conventional technology.
The purpose of this invention is to provide an exhaust gas purification device in which the three-way catalyst can always exhibit its original purification ability while preventing the temperature of the catalyst in its activated state from becoming excessively high.
本考案の排気ガス浄化装置は、三元触媒の活性
状態における温度が異常に上昇して所定値よりも
高くなつた時には、排気系の二次空気の供給を実
質的に停止すると共に、吸気系の補助空気のみに
より、排気ガスを理論空燃比に制御することを特
徴としている。
The exhaust gas purification device of the present invention substantially stops the supply of secondary air to the exhaust system when the temperature of the three-way catalyst in the active state rises abnormally and becomes higher than a predetermined value, and also stops the supply of secondary air to the intake system. The exhaust gas is controlled to the stoichiometric air-fuel ratio using only auxiliary air.
前述のように、吸気として供給される混合気の
空燃比は、出力、運転性、燃費率等の要請から理
論空燃比よりもかなり小さく（濃く）なつている
が、三元触媒は理論空燃比付近の狭い空燃比の範
囲でないと良好な浄化効率が得られないので、不
足分の空気量を排気系での二次空気によつて補う
結果、運転状態によつては三元触媒の活性状態の
温度が異常に上昇することがある。
As mentioned above, the air-fuel ratio of the air-fuel mixture supplied as intake air is much lower (richer) than the stoichiometric air-fuel ratio due to requirements such as output, drivability, and fuel efficiency. Good purification efficiency cannot be obtained unless the air-fuel ratio is in a narrow range, so the lack of air volume is compensated for by secondary air in the exhaust system, and depending on the operating condition, the activation state of the three-way catalyst may temperature may rise abnormally.
本考案では異常な温度上昇を検出すると二次空
気を実質的に停止して温度を低下させるが、それ
にとどまらず、吸気系の補助空気を増量制御する
ことにより、排気ガスの空燃比を理論空燃比付近
に維持するように自動的に制御する点に特徴があ
り、それによつて、三元触媒の良好な浄化効率
が、異常な状態でも維持される。 In this invention, when an abnormal temperature rise is detected, the secondary air is effectively stopped and the temperature is lowered.In addition, by increasing the amount of auxiliary air in the intake system, the air-fuel ratio of the exhaust gas is adjusted to the stoichiometric ratio. The feature is that the fuel ratio is automatically controlled to be maintained near the fuel ratio, thereby maintaining the good purification efficiency of the three-way catalyst even under abnormal conditions.
吸気における空燃比が大きく（薄く）なり、二
次空気が停止されることによつて、三元触媒の異
常な温度上昇がなくなると、自動的に再び二次空
気供給が再開され、吸気の空燃比も小さくなるこ
とは言うまでもない。 When the air-fuel ratio in the intake air increases (leans) and the secondary air is stopped, the abnormal temperature rise of the three-way catalyst disappears, the secondary air supply is automatically resumed and the intake air is stopped. Needless to say, the fuel ratio will also become smaller.
第１図は本考案の一実施例を示し、エンジン本
体１に接続するインテークマニホールド２には、
気化器３が取付けられ、この気化器３の燃料通路
４には空気通路５が連通する。エアブリード制御
弁６は、空気通路５の途中に設けられ、エアフイ
ルタ７を介して該通路５に補助空気を導くもの
で、後述するように演算器８により開閉制御され
る。すなわちエアブリード制御弁６はエンジン本
体１に給送される濃い混合気の空燃比を若干大き
くして理論空燃比に近づけるように作用する。
FIG. 1 shows an embodiment of the present invention, in which an intake manifold 2 connected to an engine body 1 includes:
A carburetor 3 is attached, and an air passage 5 communicates with a fuel passage 4 of this carburetor 3. The air bleed control valve 6 is provided in the middle of the air passage 5 and guides auxiliary air into the passage 5 via an air filter 7, and is controlled to open and close by a computing unit 8 as described later. That is, the air bleed control valve 6 acts to slightly increase the air-fuel ratio of the rich air-fuel mixture fed to the engine main body 1 so as to bring it closer to the stoichiometric air-fuel ratio.
エンジン本体１の下流側に接続するエキゾース
トマニホールド９には空気通路１０が連通し、こ
の空気通路１０の途中には、リード弁１１、二次
空気制御弁１２およびエアフイルタ１３が設けら
れる。リード弁１１は、二次空気制御弁１２が開
放している時、エキゾーストマニホールド９内の
脈動圧の負圧成分に応じて開弁し、エキゾースト
マニホールド９内に二次空気を供給する。二次空
気制御弁１２は、排気ガスの空燃比が理論空燃比
になるように、上記エアブリード制御弁６と同様
に演算器８により開閉制御される。 An air passage 10 communicates with an exhaust manifold 9 connected to the downstream side of the engine body 1, and a reed valve 11, a secondary air control valve 12, and an air filter 13 are provided in the middle of the air passage 10. When the secondary air control valve 12 is open, the reed valve 11 opens in response to the negative pressure component of the pulsating pressure within the exhaust manifold 9 and supplies secondary air into the exhaust manifold 9. The secondary air control valve 12 is controlled to open and close by the computing unit 8 in the same manner as the air bleed control valve 6 so that the air-fuel ratio of the exhaust gas becomes the stoichiometric air-fuel ratio.
エキゾーストマニホールド９の下流側には、排
気ガスの空燃比を検知するO2センサ１５が取付
けられ、さらにその下流側の排気管１４には三元
触媒１６を収容する触媒コンバータ１７が設けら
れる。温度センサ１８は触媒コンバータ１７内に
臨み、触媒の活性状態の温度を検知する。O2セ
ンサ１５および温度センサ１８の検知データは、
それぞれ演算器８へ送られる。 An O 2 sensor 15 that detects the air-fuel ratio of exhaust gas is attached to the downstream side of the exhaust manifold 9, and a catalytic converter 17 that accommodates a three-way catalyst 16 is further provided in the exhaust pipe 14 on the downstream side. Temperature sensor 18 faces inside catalytic converter 17 and detects the temperature of the catalyst in its active state. The detection data of the O 2 sensor 15 and temperature sensor 18 are as follows:
Each is sent to the arithmetic unit 8.
演算器８は、O2センサ１５から入力された排
気ガスの空燃比と理論空燃比との偏差を求め、そ
の偏差量および温度センサ１８から得られた触媒
の活性状態の温度に応じて上記エアブリード制御
弁６および二次制御弁１２の開閉制御を行なう。 The calculator 8 calculates the deviation between the air-fuel ratio of the exhaust gas inputted from the O 2 sensor 15 and the stoichiometric air-fuel ratio, and adjusts the air-fuel ratio according to the amount of deviation and the temperature in the active state of the catalyst obtained from the temperature sensor 18. Controls opening and closing of the bleed control valve 6 and the secondary control valve 12.
本実施例装置は次のように動作して三元触媒１
６を適正な温度に保ち、この触媒１６の正常な排
気浄化作用を維持する。すなわち、触媒の活性状
態の温度が所定温度Ｔ（例えば900℃）より低い場
合、吸気系および排気系の双方に補正空気を導入
すべく、エアブリード制御弁６および二次空気制
御弁１２を開放する。これに対し、触媒の活性状
態の温度が所定温度Ｔより高い場合、排気系への
二次空気の供給を停止すべく、二次空気制御弁１
２を閉塞する（第２図参照）。 The device of this embodiment operates as follows, and the three-way catalyst 1
6 at an appropriate temperature to maintain the normal exhaust gas purifying action of this catalyst 16. That is, when the temperature of the active state of the catalyst is lower than a predetermined temperature T (for example, 900°C), the air bleed control valve 6 and the secondary air control valve 12 are opened to introduce correction air into both the intake system and the exhaust system. do. On the other hand, when the temperature of the active state of the catalyst is higher than the predetermined temperature T, the secondary air control valve 1
2 (see Figure 2).
したがつて、エンジン本体１から排出された排
気ガスは、従来のように二次空気により温度上昇
することがなくなり、これにより、三元触媒１６
が異常に高温になることが防止されるとともに、
車両熱害の虞れがなくなる。 Therefore, the temperature of the exhaust gas discharged from the engine body 1 does not rise due to the secondary air as in the conventional case, and as a result, the three-way catalyst 16
This prevents the temperature from becoming abnormally high, and
There is no risk of vehicle heat damage.
なお、排気系へ二次空気を供給する手段として
は、上述のようにリード弁１１を用いたエアサク
シヨン型のものにする必要はなく、エアポンプを
用いた構造にしてもよい。 Note that the means for supplying secondary air to the exhaust system does not need to be of the air suction type using the reed valve 11 as described above, and may be structured using an air pump.
以上のように本考案によれば、触媒の活性状態
の温度が異常に高くなることが防止されるので、
触媒の耐久性が向上するとともに、車両熱害が防
止され、また三元触媒の活性状態の温度が高くな
つたときは二次空気を止め、代りに吸気系に供給
する空気量を増して、排気ガスが常に理論空燃比
になるように制御するので、三元触媒を常に理想
的な状態で使用することが可能となるという効果
が得られる。
As described above, according to the present invention, the temperature in the active state of the catalyst is prevented from becoming abnormally high.
This improves the durability of the catalyst, prevents vehicle heat damage, and when the temperature of the active state of the three-way catalyst becomes high, the secondary air is stopped and the amount of air supplied to the intake system is increased instead. Since the exhaust gas is controlled so that it always has the stoichiometric air-fuel ratio, it is possible to always use the three-way catalyst in an ideal state.
第１図は本考案の一実施例を示し、一部を断面
とした概略側面図、第２図はエアブリード制御弁
と二次空気制御弁の開閉状態を示すグラフであ
る。
６……エアブリード制御弁、１２……二次空気
制御弁、１５……O2センサ、１６……三元触媒
（排気ガス浄化用触媒）、１８……温度センサ。
FIG. 1 shows an embodiment of the present invention, and is a schematic side view, partially in section, and FIG. 2 is a graph showing the opening and closing states of the air bleed control valve and the secondary air control valve. 6... Air bleed control valve, 12... Secondary air control valve, 15... O 2 sensor, 16... Three-way catalyst (exhaust gas purification catalyst), 18... Temperature sensor.
Claims (1)
を理論空燃比に近づけるとともに、排気系に二次
空気を供給して、排気ガス浄化用三元触媒に流入
する排気ガスを理論空燃比に制御する排気ガス浄
化装置において、上記三元触媒の活性状態におけ
る温度が所定値より高い異常時においてのみ、排
気系の二次空気の供給を停止し、排気系に設けら
れた酸素濃度センサの信号に基いて吸気系の補助
空気のみにより、排気ガスを理論空燃比に制御す
るようにしたことを特徴とする排気ガス浄化装
置。 Auxiliary air is introduced into the engine intake system to bring the air-fuel mixture close to the stoichiometric air-fuel ratio, and secondary air is supplied to the exhaust system to control the exhaust gas flowing into the three-way catalyst for exhaust gas purification to the stoichiometric air-fuel ratio. In an exhaust gas purification device, the supply of secondary air to the exhaust system is stopped only when the temperature in the activated state of the three-way catalyst is higher than a predetermined value, and the signal from the oxygen concentration sensor installed in the exhaust system is An exhaust gas purification device characterized in that the exhaust gas is controlled to a stoichiometric air-fuel ratio using only auxiliary air in the intake system.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15908682U JPS5964457U (en) | 1982-10-22 | 1982-10-22 | Exhaust gas purification device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15908682U JPS5964457U (en) | 1982-10-22 | 1982-10-22 | Exhaust gas purification device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5964457U JPS5964457U (en) | 1984-04-27 |
| JPH021473Y2 true JPH021473Y2 (en) | 1990-01-16 |
Family
ID=30350298
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15908682U Granted JPS5964457U (en) | 1982-10-22 | 1982-10-22 | Exhaust gas purification device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5964457U (en) |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5243019A (en) * | 1975-10-02 | 1977-04-04 | Nissan Motor Co Ltd | Thermal controlling apparatus exhaust purging system |
| JPS5521176A (en) * | 1978-08-02 | 1980-02-15 | Tdk Corp | Semiconductor device |
| JPS5657913U (en) * | 1979-10-12 | 1981-05-19 | ||
| JPS5666415A (en) * | 1979-10-31 | 1981-06-04 | Toyota Motor Corp | Air/fuel ratio control device for engine |
-
1982
- 1982-10-22 JP JP15908682U patent/JPS5964457U/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5964457U (en) | 1984-04-27 |
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