JPH01227815A - Exhaust gas purifying device - Google Patents
Exhaust gas purifying deviceInfo
- Publication number
- JPH01227815A JPH01227815A JP63053159A JP5315988A JPH01227815A JP H01227815 A JPH01227815 A JP H01227815A JP 63053159 A JP63053159 A JP 63053159A JP 5315988 A JP5315988 A JP 5315988A JP H01227815 A JPH01227815 A JP H01227815A
- Authority
- JP
- Japan
- Prior art keywords
- engine
- catalyst
- exhaust gas
- secondary air
- valve
- 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
- 239000000446 fuel Substances 0.000 claims abstract description 46
- 239000003054 catalyst Substances 0.000 claims abstract description 43
- 238000000746 purification Methods 0.000 claims description 14
- 239000000203 mixture Substances 0.000 claims description 12
- 238000006243 chemical reaction Methods 0.000 claims description 3
- 238000002485 combustion reaction Methods 0.000 claims description 3
- 239000010948 rhodium Substances 0.000 abstract description 11
- 235000014676 Phragmites communis Nutrition 0.000 abstract description 4
- 229910052703 rhodium Inorganic materials 0.000 abstract description 4
- 238000011144 upstream manufacturing Methods 0.000 abstract description 4
- 230000003197 catalytic effect Effects 0.000 abstract 2
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 abstract 2
- 238000010792 warming Methods 0.000 abstract 1
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical class O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 21
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 18
- 239000007789 gas Substances 0.000 description 18
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 9
- 239000001301 oxygen Substances 0.000 description 9
- 229910052760 oxygen Inorganic materials 0.000 description 9
- 238000010586 diagram Methods 0.000 description 7
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 6
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 description 4
- 239000000498 cooling water Substances 0.000 description 3
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 230000004913 activation Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 150000002926 oxygen Chemical class 0.000 description 1
- 230000010349 pulsation Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/40—Engine management systems
Landscapes
- Exhaust Gas After Treatment (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、自動車用エンジンの排気ガス浄化装置に関し
、特に、メタノールを燃料とするエンジンでの排気ガス
浄化装置に関する。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an exhaust gas purification device for an automobile engine, and particularly to an exhaust gas purification device for an engine using methanol as fuel.
（従来の技術）
周知のように、自動車用エンジンの燃料として安価なメ
タノールを用いることが提案されている。(Prior Art) As is well known, it has been proposed to use inexpensive methanol as a fuel for automobile engines.
（発明が解決しようとする課題）
ところで、上述したメタノールを用いる場合にあっては
、例えば、低温始動後の暖気運転時において、第５図示
のように、有害成分であるホルムアルデヒドが大量に発
生するとされている。(Problem to be Solved by the Invention) By the way, when using the above-mentioned methanol, for example, during warm-up operation after starting at a low temperature, a large amount of formaldehyde, which is a harmful component, may be generated as shown in Figure 5. has been done.
このホルムアルデヒドは、〔表１〕で示すように、白金
（Ｐｔ）−ロジュウム（Ｒｈ）系の三元触媒（ＴυＣ）
によって浄化するのが効率が良いとされ、かつ、混合気
が理論空燃比よりもリーンな条件下、換言すれば、酸素
が過剰に含まれている状態において早く浄化されるが、
しかしながら、低温始動時等においては、混合気は理論
空燃比に対して、リッチな条件下となっているため、上
述した条件と異なり、ホルムアルデヒドの発生が顕著と
なるという問題があった。しかも、上述したように、ホ
ルムアルデヒドを効率良く除去するための条件である過
剰酸素供給状態では、触媒内での温度が上昇し、これに
よって、排気ガス温度も上昇することになるので、排気
ガス中でＮＯｘが増加するという新たな問題が生じる虞
れもあった。As shown in Table 1, this formaldehyde is produced using a platinum (Pt)-rhodium (Rh) three-way catalyst (TυC).
It is said that it is more efficient to purify the air-fuel mixture by using air-fuel ratio, and the air-fuel mixture is purified more quickly when the air-fuel mixture is leaner than the stoichiometric air-fuel ratio, in other words, when it contains excess oxygen.
However, during low-temperature startup, etc., the air-fuel mixture is under conditions that are rich with respect to the stoichiometric air-fuel ratio, so unlike the above-mentioned conditions, there is a problem in that formaldehyde generation becomes noticeable. Moreover, as mentioned above, in the state of excessive oxygen supply, which is a condition for efficiently removing formaldehyde, the temperature inside the catalyst increases, which also causes the exhaust gas temperature to rise. There was also the risk that a new problem would arise, such as an increase in NOx.
このような現象は、第６図示のように、暖機時間と空気
過剰率とに対する空気供給時間によるホルムアルデヒド
、および、ＮＯｘの浄化率を表す関係からも明らかにさ
れている（例えば、自工会論文集Ｎα３６，１９８７）
。This phenomenon is also clarified from the relationship between warm-up time and excess air ratio, as well as formaldehyde and NOx purification rates depending on air supply time, as shown in Figure 6. Nα36, 1987)
.
〔表 １ ） （ＳＥＡ８７２０５２）Ａｌｄｅｈｙｄ
ｅ Ｅｆｆｉｃｉｅｎｃｙ−ＦＴＰ Ｄｒｉｖｉｎｇ
ＣｙｃｌｅＴｈｒｅｅ−Ｗａｙ Ｏｐｅｒａｔｉｎｇ
Ｍｏｄｅ１２Ｐｔ：Ｒｈ（４０）
９５．４（％）１２Ｐｔ ： Ｒｈ （４０）
Ｒ９５，４９Ｐｔ：Ｒｈ（１０）
９２．５５Ｐｔ：Ｒｈ（４０）
９１．９ＣｕＯ８９，２
Ｐｄ（１０） ８８
．２３Ｐｔ ： ２Ｐｄ （２０）
８６．９Ｐｄ＋ＢＭ（５）
８４．８Ｐｄ（２０） −８
３，７
Ｐｄ （４０） ８
３．７Ａｇ（１５０）
７６．５１０Ａｇ：Ｒｈ（１５０）
６６．８Ｐｄ＋ＢＭ （３５）
５２・８（目 的）
そこで本発明の目的は、混合気の空燃比に応じて発生す
る有害物質、特に、安価な燃料を用いた場合の低温始動
時を含む暖機運転時において触媒が活性化状態に移行す
るまでの間に発生する有害成分を略完全に除去して経済
的な燃料の使用を可能にできる新規な排気ガス浄化装置
を得ることにある。[Table 1] (SEA872052) Aldehyd
e Efficiency-FTP Driving
CycleThree-Way Operating
Mode12Pt:Rh(40)
95.4 (%) 12Pt: Rh (40)
R95,49Pt:Rh(10)
92.55Pt:Rh(40)
91.9CuO89,2 Pd(10) 88
．． 23Pt: 2Pd (20)
86.9Pd+BM(5)
84.8Pd(20) -8
3,7 Pd (40) 8
3.7Ag (150)
76.510Ag:Rh(150)
66.8Pd+BM (35)
52.8 (Purpose) Therefore, the purpose of the present invention is to prevent harmful substances generated depending on the air-fuel ratio of the air-fuel mixture, especially when the catalyst is activated during warm-up including low-temperature starting when using inexpensive fuel. It is an object of the present invention to provide a new exhaust gas purifying device that can substantially completely remove harmful components generated before the transition to a state of combustion, thereby making it possible to use economical fuel.
（課題を解決するための手段）
この目的を達成するため、本発明は、排気ガスの流動方
向における排気ガス浄化用触媒の上流側に、上記触媒内
で燃焼時と同じ化学反応を起こさせるための２次空気を
供給するようにし、この２次空気の供給時期を、エンジ
ンの低温始動時において、排気ガスの空燃比を基に三元
触媒に対する空燃比のフィードバック制御が行われる暖
機運転に至るまでの間、換言すれば、触媒が活性化する
までの間とすることを提案するものである。(Means for Solving the Problems) In order to achieve this object, the present invention provides a method for causing the same chemical reaction as during combustion within the catalyst on the upstream side of the exhaust gas purifying catalyst in the flow direction of exhaust gas. The supply timing of this secondary air is set during warm-up operation in which feedback control of the air-fuel ratio to the three-way catalyst is performed based on the air-fuel ratio of exhaust gas when the engine is started at a low temperature. In other words, it is proposed that the catalyst be activated.
（作 用）
本発明によれば、低温始動時において有害成分であるホ
ルムアルデヒドを大量に発生するメタノールを用いたエ
ンジンにおいて、低温始動時から、触媒が活性化して１
通常の三元触媒を用いた排気ガス浄化が行なえる暖機運
転に至るまでの間には、触媒に対する酸素を含む２次空
気の供給を可能にしてホルムアルデヒドの浄化を促進し
、暖機時、換言すれば、触媒が活性化した時点では、通
常の排気ガスの空燃比検出による排気ガス浄化を行ない
、ＮＯｘの発生を低下させる。(Function) According to the present invention, in an engine using methanol that generates a large amount of formaldehyde, which is a harmful component, when started at low temperature, the catalyst is activated and
During warm-up, when exhaust gas purification can be performed using a normal three-way catalyst, secondary air containing oxygen can be supplied to the catalyst to promote formaldehyde purification. In other words, when the catalyst is activated, the exhaust gas is purified by normal detection of the air-fuel ratio of the exhaust gas, and the generation of NOx is reduced.
（実 施 例）
以下、第１図乃至第３図において、本発明実施例の詳細
を説明する。(Embodiment) Hereinafter, details of an embodiment of the present invention will be explained with reference to FIGS. 1 to 3.
第１図は、本発明実施例による排気ガス浄化装置全体構
成を示すブロック図である。FIG. 1 is a block diagram showing the overall configuration of an exhaust gas purification apparatus according to an embodiment of the present invention.
図において、エンジン１の排気管ｌａ中には、矢印Ａで
示す排気ガスの流動方向におけるマフラ（図示されず）
に至る上流側に、例えば、白金（Ｐｔ）−ロジュウム（
Ｒｈ）系の三元触媒２が位置し、そして、排気ガスの流
動方向における三元触媒２の上流側には、２次空気の取
り入れ口１ａｌが形成しである。In the figure, in the exhaust pipe la of the engine 1, there is a muffler (not shown) in the flow direction of exhaust gas indicated by arrow A.
For example, platinum (Pt)-rhodium (
A Rh) system three-way catalyst 2 is located, and a secondary air intake port 1al is formed upstream of the three-way catalyst 2 in the flow direction of exhaust gas.
この取り入れ口１ａｌには、２次空気の供給部３が接続
してあり、この２次空気供給部３は、吸気系の始端側に
位置するエアクリーナ３Ａと、このエアクリーナ３Ａか
らの外気を排気の脈動を利用して排気管ｌａ内に導入す
るリード弁３Ｂとで構成されている。そして、上述した
リード弁３Ｂと排気管１ａとを連絡する供給パイプ３Ｃ
の途中には、２次空気供給弁４が配置されている。A secondary air supply section 3 is connected to this intake port 1al, and this secondary air supply section 3 is connected to an air cleaner 3A located at the starting end side of the intake system and the outside air from this air cleaner 3A to the exhaust system. It is comprised of a reed valve 3B that introduces the air into the exhaust pipe la using pulsation. A supply pipe 3C that connects the above-mentioned reed valve 3B and the exhaust pipe 1a
A secondary air supply valve 4 is arranged in the middle.
すなわち、この２次空気供給弁４は、２次空気の供給を
制御するために供給パイプ３Ｃを開閉するものであって
、本実施例の場合、供給パイプ３Ｃに連結された２次空
気通過部４ａと背圧部４ｂとの間にダイアフラム４Ａを
用いた負圧作動弁で構成され、２次空気通過部４ａに対
向するダイアフラム４Ａの面には供給パイプ３Ｃを開閉
する弁本体４Ｃがそして、背圧部４ｂに対向するダイア
フラム４Ａの面には圧縮バネ４ｄがそれぞれ設けである
。That is, this secondary air supply valve 4 opens and closes the supply pipe 3C in order to control the supply of secondary air, and in the case of this embodiment, the secondary air passage portion connected to the supply pipe 3C. 4a and a back pressure part 4b, the diaphragm 4A is configured with a negative pressure operated valve, and on the surface of the diaphragm 4A facing the secondary air passage part 4a, there is a valve body 4C for opening and closing the supply pipe 3C. Compression springs 4d are provided on the surface of the diaphragm 4A facing the back pressure portion 4b.
上述した２次空気供給弁４における背圧部４ｂには、供
給パイプ３ｃを開放する向きに弁本体４Ｃを移動付勢す
る負圧発生部５が接続されている。A negative pressure generating section 5 is connected to the back pressure section 4b of the secondary air supply valve 4 described above, which biases the valve body 4C in a direction to open the supply pipe 3c.
すなわち、この負圧発生部５は、例えば、電磁駆動式の
切り換え弁５Ａと、２次空気供給弁４の背圧部４ｂとエ
ンジン１の吸気管１ｂとの間に連結された負圧管５Ｂと
を備えている。That is, the negative pressure generating section 5 includes, for example, an electromagnetically driven switching valve 5A, a negative pressure pipe 5B connected between the back pressure section 4b of the secondary air supply valve 4, and the intake pipe 1b of the engine 1. It is equipped with
一方、上述した負圧発生部５における切り換え弁５Ａは
、第２図に示す制御部６に電気的接続されて切り換え方
向および１作動時期を制御され、これに追随して２次空
気供給弁４が開閉を制御されるようになっている。On the other hand, the switching valve 5A in the negative pressure generating section 5 described above is electrically connected to the control section 6 shown in FIG. 2 to control the switching direction and one operation timing. The opening and closing are controlled.
すなわち制御部６は、第２図示のように、Ｉ１０インタ
ーフェイス６Ａに接続された演算処理部を成すマイクロ
コンピュータ６Ｂを備えており、上述したＩ１０インタ
ーフェイス６Ａには、第１図および第３図に示すように
、排気管ｌａ内での残留酸素濃度を検知して、理論空燃
比に対する排気ガス空燃比のリッチ、リーン状態を検出
するためのＥＧＯセンサ６ａからの信号、エンジン側で
の始動、暖機状態を検出するためのエンジン側での回転
数および、アクセル関度等を検出するセンサ６Ｃ１６ｄ
からのエンジン出力データを表す信号、ならびに、エン
ジン温度（冷却水温度）を検出するセンサ（図示されず
）からの信号がそれぞれ入力されると共に、三元触媒２
内の温度センサ６ｂからの信号が入力される。上述した
各信号のうち、三元触媒２からの温度信号以外の信号は
、混合気が理論空燃比よりもリッチな条件下にあるかあ
るいは、リーンな条件下にあるかを割り出すためのデー
タとなるものである。That is, as shown in FIG. 2, the control section 6 includes a microcomputer 6B serving as an arithmetic processing section connected to the I10 interface 6A. , a signal from the EGO sensor 6a is sent to detect the residual oxygen concentration in the exhaust pipe la and detect whether the exhaust gas air-fuel ratio is rich or lean relative to the stoichiometric air-fuel ratio, and the engine starts and warms up. A sensor 6C16d that detects the engine speed and accelerator function, etc. to detect the state
A signal representing engine output data from the three-way catalyst 2 and a signal from a sensor (not shown) that detects the engine temperature (cooling water temperature) are respectively input.
A signal from the internal temperature sensor 6b is input. Among the above-mentioned signals, the signals other than the temperature signal from the three-way catalyst 2 are data for determining whether the air-fuel mixture is under conditions richer or leaner than the stoichiometric air-fuel ratio. It is what it is.
そして、マイクロコンピュータ６Ｂでは、ＲＯＭ６Ｃで
の制御プログラムおよび、演算のための基礎データに基
づいて位置切り換え弁５Ａの駆動制御および、駆動時期
の設定を行ない、２次空気供給弁４の開閉制御を行なう
ようになっている。The microcomputer 6B controls the drive of the position switching valve 5A, sets the drive timing, and controls the opening and closing of the secondary air supply valve 4 based on the control program in the ROM 6C and basic data for calculation. It looks like this.
すなわち、ＲＯＭ６Ｃには、エンジン側での低温始動時
、あるいは三元触媒が活性化していることを判別するた
めの基礎データ、ならびに、混合気の理論空燃比に対す
るリッチ、リーン条件を判別するための基礎データ、お
よび、三元触媒での触媒による浄化能率が低下する要因
、例えば、触媒が熱劣化を起こす温度や耐久性の低下を
来す酸素（０２）の存在量に関するデータがそれぞれ納
められており、これらのデータを基に、マイクロコンピ
ュータ６Ｂにおいて、上述した各部からの入力情報を演
算処理することで２次空気供給弁４の開閉状態が設定さ
れる。In other words, ROM6C contains basic data for determining when the engine starts at a low temperature or when the three-way catalyst is activated, as well as basic data for determining rich and lean conditions for the stoichiometric air-fuel ratio of the air-fuel mixture. It contains basic data and data on factors that reduce the purification efficiency of a three-way catalyst, such as the temperature at which the catalyst thermally deteriorates and the amount of oxygen (02) that causes a decrease in durability. Based on these data, the open/close state of the secondary air supply valve 4 is set by arithmetic processing of the input information from each section mentioned above in the microcomputer 6B.
本実施例の場合、上述した各部からの信号において、低
温始動時等、混合気が、理論空燃比よりもリッチな条件
下になった場合には、吸気管１ｂからの負圧付勢を介し
２次空気供給弁４が開放される向きに切り換え弁５Ａを
作動させる指令がマイクロコンピュータ６Ｂから出され
、かつ、この状態において、触媒２内の温度が触媒の熱
劣化を起こす虞れのある温度にまで上昇した時点で、２
次空気供給弁４を閉鎖する向きに作動させる指令がマイ
クロコンピュータ６Ｂから切り換え弁５Ａに対して出さ
れるようになっている。このときの切り換え弁５Ａは、
２次空気供給弁４における背圧部４ａを大気開放するこ
とができる状態とされ、これによって、２次空気供給弁
４は、弁本体４ｃが圧縮バネ４ｄの付勢を受けることに
より供給パイプ３Ｃを閉鎖する。In the case of this embodiment, when the air-fuel mixture becomes richer than the stoichiometric air-fuel ratio, such as during a low-temperature start, the signals from each part mentioned above are activated via negative pressure energization from the intake pipe 1b. A command to operate the switching valve 5A in the direction in which the secondary air supply valve 4 is opened is issued from the microcomputer 6B, and in this state, the temperature inside the catalyst 2 is at a temperature that may cause thermal deterioration of the catalyst. 2.
A command to close the air supply valve 4 is issued from the microcomputer 6B to the switching valve 5A. At this time, the switching valve 5A is
The back pressure portion 4a of the secondary air supply valve 4 is brought into a state where it can be released to the atmosphere, and thereby the secondary air supply valve 4 is able to open the supply pipe 3C by the valve body 4c being biased by the compression spring 4d. will be closed.
本実施例は以上のような構造であるから、その作用は第
４図に示すフローチャートの通りである。Since this embodiment has the above-described structure, its operation is as shown in the flow chart shown in FIG.
すなわち、エンジン運転状態にあると、Ｉ１０インター
フェイス６Ａに対して各部からの信号が入力され、エン
ジン側での回転数、アクセル開度および、ＥＧＯセンサ
６ａからの情報によって、エンジンの冷却水の温度に基
づいてエンジンの低温始動時であるかどうかを判別しく
５ＴＩ）、エンジンが低温始動時にある場合、換言すれ
ば、混合気が理論空燃比よりもリッチ条件下にある場合
には、三元触媒２の温度を検出して、触媒２が活性化し
ていると同等の温度であるかを判別しく５Ｔ２）、かつ
、その温度が所定温度以下であるかどうかを判別したう
えで（Ｓｒ１）、所定温度以下であれば、切り換え弁５
Ａが、２次空気供給弁４を開放するように切り換えられ
る（Ｓｒ１）。That is, when the engine is in operation, signals from various parts are input to the I10 interface 6A, and the temperature of the engine cooling water is adjusted based on the engine speed, accelerator opening, and information from the EGO sensor 6a. 5TI), if the engine is starting at a low temperature, in other words, if the air-fuel mixture is richer than the stoichiometric air-fuel ratio, the three-way catalyst 2 5T2) and determine whether the temperature is below a predetermined temperature (Sr1). If it is below, the switching valve 5
A is switched to open the secondary air supply valve 4 (Sr1).
一方、上述したように、２次空気供給弁４が開放される
と、リード弁３Ｂを介して排気管１ａにおける三元触媒
２の上流側に酸素を含む２次空気が供給されることにな
るが、この酸素の供給によって生じる化学反応により、
三元触媒２内での温度が上昇して行き、触媒の熱劣化を
招く温度１例えば８５０℃に上昇した場合には、マイク
ロコンピュータ６Ｂから切り換え弁５Ａに対し、２次空
気供給弁４を閉鎖させる向きの作動指令が出され、これ
により排気管１ａへの２次空気の供給が停止される（Ｓ
ｒ１）。On the other hand, as described above, when the secondary air supply valve 4 is opened, secondary air containing oxygen is supplied to the upstream side of the three-way catalyst 2 in the exhaust pipe 1a via the reed valve 3B. However, due to the chemical reaction caused by this oxygen supply,
When the temperature inside the three-way catalyst 2 rises and reaches a temperature 1, for example 850°C, which causes thermal deterioration of the catalyst, the microcomputer 6B instructs the switching valve 5A to close the secondary air supply valve 4. An operation command is issued in the direction of
r1).
なお、上述したステップにおいて、三元触媒２の温度が
、その触媒２の活性化が行われている値である場合には
、触媒２でのホルムアルデヒドの浄化が可能となる酸素
を含んでいる場合と同等な状態であるので、マイクロコ
ンピュータ６Ｂでは、２次空気供給弁を閉鎖する指令が
切り換え弁５Ａに出される（Ｓｒ１）。In addition, in the above-mentioned step, if the temperature of the three-way catalyst 2 is a value at which the catalyst 2 is activated, if the catalyst 2 contains oxygen that can purify formaldehyde. Therefore, the microcomputer 6B issues a command to the switching valve 5A to close the secondary air supply valve (Sr1).
そして、上述したＩ１０インターフェイス６Ａに対して
各部からの信号が入力され、エンジン側での温度、所謂
、冷却水の温度が低温始動時を外れて暖機運転状態と判
断される値に達すると、上述したように２次空気供給弁
４が閉鎖されることにより２次空気の供給制御が終了し
、過剰な酸素の供給が停止されて触媒温度の上昇により
起こるＮＯｘの増加を防ぎ、一方、三元触媒２における
浄化効率を良好にするため、ＥＧＯセンサ６ｂからの信
号に基づいて理論空燃比に対する混合気の空燃比をリッ
チ、リーンに該当するかどうかを判別し、理論空燃比と
するため、第３図示の燃料制御部７において燃料噴射ノ
ズル７Ａ（第１図参照）からの燃料のメータリング制御
を行ない、ＮＯｘの増加を抑えると共に、他の有害成分
である、ＨＣｌならびに、ＣＯの発生も抑制する。この
ような２次空気の供給制御は、第４図中、符号ＳＴ６で
示すように、エンジンの動作が停止される間で、継続し
て行われる。Then, signals from various parts are input to the above-mentioned I10 interface 6A, and when the temperature on the engine side, the so-called cooling water temperature, reaches a value that is determined to be a warm-up operation state outside of the low temperature starting time, As described above, by closing the secondary air supply valve 4, the secondary air supply control is terminated, and excessive oxygen supply is stopped to prevent an increase in NOx caused by an increase in catalyst temperature. In order to improve the purification efficiency in the main catalyst 2, it is determined whether the air-fuel ratio of the air-fuel mixture with respect to the stoichiometric air-fuel ratio corresponds to rich or lean based on the signal from the EGO sensor 6b, and the stoichiometric air-fuel ratio is set. The fuel control unit 7 shown in FIG. 3 performs metering control of fuel from the fuel injection nozzle 7A (see FIG. 1) to suppress the increase in NOx and also to prevent the generation of other harmful components such as HCl and CO. suppress. Such secondary air supply control is continuously performed while the engine operation is stopped, as indicated by the symbol ST6 in FIG. 4.
本実施例によれば、低温始動時において、触媒が活性化
する温度になく、所謂、三元触媒による排気ガス浄化効
率が悪い状態にあっても、２次空気の供給によって、三
元触媒の活性化を比較的短時間で行なうことができるの
で、排気ガス中の有害成分の浄化をエンジンの始動時か
ら短時間のうちに略、完全に行なうことが可能となる。According to this embodiment, even when the catalyst is not activated at a low temperature and the exhaust gas purification efficiency of the three-way catalyst is poor during low-temperature startup, the three-way catalyst is activated by supplying secondary air. Since activation can be carried out in a relatively short time, harmful components in exhaust gas can be almost completely purified within a short time from the time the engine is started.
（発明の効果）
以上、本発明によれば、安価な燃料であるメタノールを
用いるエンジンの低温始動時において大量に発生するホ
ルムアルデヒドを、エンジンの低温時における始動開始
から短時間のうちに完全に浄化することができるので、
有害成分を出す虞れのある経済的な燃料の使用を可能に
できるエンジンが得られる。(Effects of the Invention) As described above, according to the present invention, formaldehyde, which is generated in large quantities when an engine using methanol, which is an inexpensive fuel, is started at a low temperature can be completely purified within a short time from the start of the engine at a low temperature. Because you can
An engine is obtained that allows economical use of fuel that may emit harmful components.
第１図は本発明実施例による排気ガス浄化装置を示す全
体構成図、第２図は第１図に示した排気ガス装置におけ
る制御部を示すブロック図、第３図は第１図に示した全
体構成における制御系を示すブロック図、第４図は第２
図に示した制御部の作用を説明するためのフローチャー
ト、第５図は燃料としてメタノールを用いた場合のエン
ジン始動後におけるホルムアルデヒドの排出量を示す線
図、第６図は第５図に用いたエンジンでの始動後の経過
時間とホルムアルデヒド、およびＮＯｘの浄化率との関
係を示す線図である。
１・・・エンジン、２・・・三元触媒、３・・・２次空
気供給部、３Ｃ・・・供給パイプ、４・・・２次空気供
給弁、５・・・２次空気供給弁駆動用負圧発生部、６．
。
・制御部、６ａ・・・ＥＧＯセンサ、６ｂ・・・触媒温
度センサ、６Ａ・・・Ｉ１０インターフェイス、６Ｂ・
・・演算処理部、７・・・燃料制御部。
壺ｆｔＥｌ？
／６
／外２■
％５図
ｖ？６図FIG. 1 is an overall configuration diagram showing an exhaust gas purification device according to an embodiment of the present invention, FIG. 2 is a block diagram showing a control section in the exhaust gas device shown in FIG. 1, and FIG. A block diagram showing the control system in the overall configuration, Figure 4 is the second
Figure 5 is a flowchart to explain the action of the control unit shown in Figure 5. Figure 5 is a diagram showing formaldehyde emissions after the engine starts when methanol is used as fuel. Figure 6 is a diagram used in Figure 5. FIG. 2 is a diagram showing the relationship between the elapsed time after starting the engine and the purification rate of formaldehyde and NOx. DESCRIPTION OF SYMBOLS 1... Engine, 2... Three-way catalyst, 3... Secondary air supply part, 3C... Supply pipe, 4... Secondary air supply valve, 5... Secondary air supply valve Driving negative pressure generating section, 6.
.・Control unit, 6a... EGO sensor, 6b... Catalyst temperature sensor, 6A... I10 interface, 6B.
... Arithmetic processing section, 7... Fuel control section. Pot ftEl? /6 /Outside 2■ %5 figure v? Figure 6
Claims (1)
導入側で２次空気を供給することにより、上記触媒内で
燃焼と同じ化学反応を行なわせるエンジンの排気ガス浄
化装置において、 上記２次空気の供給路中に設けられ、その供給路を開閉
する２次空気供給手段と、 上記触媒内の温度を検出する手段と、 上記排気ガスの理論空燃比に対するリッチ、リーン状態
を検出する手段と、 上記エンジンの始動／暖機状態および、上記触媒からの
温度情報そして、エンジンに供給される混合気の理論空
燃比に対するリッチ、リーンの各条件を決定するための
情報をそれぞれ入力され、この入力情報に基づいて上記
２次空気供給バルブを開閉制御、ならびに上記触媒での
排気ガス浄化を有効に行なうための混合気に対する燃料
のメータリング制御を行なう制御部とを備え、 上記制御部において、エンジンの始動／暖機の判別およ
び、触媒温度が所定値であることを判別し、低温始動時
を含む暖機運転に至るまでの間でかつ、触媒温度が所定
値以下である場合には上記２次空気供給手段に対して２
次空気を供給するための指令を出し、エンジンの温度が
低温始動域を越えた暖機状態のときには、理論空燃比に
対する排気ガス空燃比のリッチ、リーン状態に基づいて
、燃料の供給制御を行なうことを特徴とする排気ガス浄
化装置。[Claims] Engine exhaust gas that causes a chemical reaction similar to combustion to occur within the catalyst by supplying secondary air to a three-way catalyst for exhaust gas purification on the exhaust gas introduction side of the catalyst. In the purification device, a secondary air supply means is provided in the secondary air supply path and opens and closes the supply path; a means for detecting the temperature inside the catalyst; means for detecting a lean state; information on the starting/warming-up state of the engine; temperature information from the catalyst; and information for determining rich and lean conditions for the stoichiometric air-fuel ratio of the air-fuel mixture supplied to the engine. and a control unit that controls opening and closing of the secondary air supply valve and controls fuel metering for the air-fuel mixture to effectively purify exhaust gas with the catalyst based on the input information. , The above control section determines whether the engine is started/warmed up, determines that the catalyst temperature is at a predetermined value, and determines whether the catalyst temperature is below the predetermined value or not until warm-up operation including during low-temperature starting. 2 for the secondary air supply means.
When the engine is warmed up and the temperature exceeds the low-temperature starting range, the fuel supply is controlled based on the rich or lean state of the exhaust gas air-fuel ratio relative to the stoichiometric air-fuel ratio. An exhaust gas purification device characterized by:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63053159A JPH01227815A (en) | 1988-03-07 | 1988-03-07 | Exhaust gas purifying device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63053159A JPH01227815A (en) | 1988-03-07 | 1988-03-07 | Exhaust gas purifying device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01227815A true JPH01227815A (en) | 1989-09-12 |
Family
ID=12935068
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63053159A Pending JPH01227815A (en) | 1988-03-07 | 1988-03-07 | Exhaust gas purifying device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01227815A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5136842A (en) * | 1990-08-01 | 1992-08-11 | Siemens Aktiengesellschaft | Method for heating an exhaust gas catalytic converter |
| DE4231575A1 (en) * | 1991-09-20 | 1993-04-01 | Hitachi Ltd | IC engine control with cold start projection for exhaust catalyser - uses secondary catalyser between main catalyser and engine to burn excess fuel during warm=up period. |
| US5456063A (en) * | 1992-07-10 | 1995-10-10 | Toyota Jidosha Kabushiki Kaisha | Secondary air supply apparatus for engine |
| US5577383A (en) * | 1991-09-20 | 1996-11-26 | Hitachi, Ltd. | Apparatus for controlling internal combustion engine |
| US6187709B1 (en) | 1995-10-30 | 2001-02-13 | Ford Global Technologies, Inc. | Palladium catalyst pre-oxidation to reduce light-off temperature |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52129833A (en) * | 1976-04-23 | 1977-10-31 | Nissan Motor Co Ltd | Air fuel ratio controller |
-
1988
- 1988-03-07 JP JP63053159A patent/JPH01227815A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52129833A (en) * | 1976-04-23 | 1977-10-31 | Nissan Motor Co Ltd | Air fuel ratio controller |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5136842A (en) * | 1990-08-01 | 1992-08-11 | Siemens Aktiengesellschaft | Method for heating an exhaust gas catalytic converter |
| DE4231575A1 (en) * | 1991-09-20 | 1993-04-01 | Hitachi Ltd | IC engine control with cold start projection for exhaust catalyser - uses secondary catalyser between main catalyser and engine to burn excess fuel during warm=up period. |
| US5577383A (en) * | 1991-09-20 | 1996-11-26 | Hitachi, Ltd. | Apparatus for controlling internal combustion engine |
| DE4231575C2 (en) * | 1991-09-20 | 2003-04-24 | Hitachi Ltd | Method and device for controlling an internal combustion engine |
| US5456063A (en) * | 1992-07-10 | 1995-10-10 | Toyota Jidosha Kabushiki Kaisha | Secondary air supply apparatus for engine |
| US6187709B1 (en) | 1995-10-30 | 2001-02-13 | Ford Global Technologies, Inc. | Palladium catalyst pre-oxidation to reduce light-off temperature |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3602615B2 (en) | Abnormality detection device for secondary air supply system of exhaust gas of internal combustion engine | |
| JPH1047048A (en) | Emission control device for internal combustion engine | |
| JP3602612B2 (en) | Idle speed control device for internal combustion engine | |
| JPH09119310A (en) | Emission control device for internal combustion engine | |
| JPH0693841A (en) | Control device for exhaust secondary air supply device in internal combustion engine | |
| JPH01227815A (en) | Exhaust gas purifying device | |
| KR100201968B1 (en) | Engine catalyst activation determining device and engine controller related thereto | |
| JPS63111256A (en) | Self-diagnosable control device for internal combustion engine | |
| JP3794179B2 (en) | Exhaust gas purification device for internal combustion engine | |
| JP2001234781A (en) | Hydrocarbon exhaust quantity reduction device for internal combustion engine | |
| JP2003065027A (en) | Control device for exhaust air temperature sensor for internal combustion engine | |
| JPH11343913A (en) | Air-fuel ratio controller for internal combustion engine | |
| JP3700221B2 (en) | Exhaust gas purification device for internal combustion engine | |
| JP4061676B2 (en) | Self-diagnosis device for secondary air supply device of internal combustion engine | |
| JPH06212959A (en) | Exhaust emission control device of internal combustion engine | |
| JP2583226Y2 (en) | Engine secondary air supply device | |
| JPH0693840A (en) | Exhaust emission control device for internal combustion engine | |
| JP2982457B2 (en) | Secondary air supply control device for internal combustion engine | |
| JP2686525B2 (en) | Idle air-fuel ratio controller | |
| JP3467795B2 (en) | Engine exhaust purification device | |
| JPH04136413A (en) | Exhaust gas purifying device for internal combustion engine | |
| JP2000235015A (en) | Heater control device of air/fuel ratio sensor | |
| JPH0874568A (en) | Secondary air feeding method of internal combustion engine and device thereof | |
| JPH11311118A (en) | Exhaust emission control device of turbocharged engine and control method thereof | |
| JPH01227814A (en) | Exhaust gas purifying device |