JPH05272334A - Engine exhaust device - Google Patents
Engine exhaust deviceInfo
- Publication number
- JPH05272334A JPH05272334A JP4070982A JP7098292A JPH05272334A JP H05272334 A JPH05272334 A JP H05272334A JP 4070982 A JP4070982 A JP 4070982A JP 7098292 A JP7098292 A JP 7098292A JP H05272334 A JPH05272334 A JP H05272334A
- Authority
- JP
- Japan
- Prior art keywords
- exhaust passage
- exhaust
- passage
- exhaust gas
- catalyst
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
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
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
- F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
- F01N3/2053—By-passing catalytic reactors, e.g. to prevent overheating
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
- F01N13/009—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
- F01N13/011—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more purifying devices arranged in parallel
-
- 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
- F01N2570/14—Nitrogen oxides
-
- 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
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Health & Medical Sciences (AREA)
- Toxicology (AREA)
- Exhaust Gas After Treatment (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は、エンジンの排気装置に
関し、特にNOx浄化用触媒が設けられた第1の排気通
路と該第1の排気通路から分岐し三元触媒が設けられた
第2の排気通路とを備えたエンジンの排気装置に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust system for an engine, and more particularly to a first exhaust passage provided with a NOx purification catalyst and a second exhaust passage branched from the first exhaust passage and provided with a three-way catalyst. And an exhaust passage of the engine.
【0002】[0002]
【従来の技術】自動車の排気ガスは、該排気ガス中に含
有されるCO、HC、NOxが排気ガス浄化用触媒によ
り浄化された後に大気中へ放出される。この場合、上記
排気ガス浄化用触媒としては排気ガスの温度及びCO、
HC、NOxの含有比率等に対応する浄化特性を有する
NOx浄化用触媒及び三元触媒が使い分けられたり或い
は併用されたりしている。2. Description of the Related Art Exhaust gas from an automobile is released into the atmosphere after CO, HC and NOx contained in the exhaust gas are purified by an exhaust gas purifying catalyst. In this case, the temperature of exhaust gas and CO,
A NOx purification catalyst and a three-way catalyst having purification characteristics corresponding to the content ratios of HC and NOx, etc. are used separately or used together.
【0003】そして、三元触媒は高酸素濃度下ではNO
x浄化機能が低いことが知られており、またNOx浄化
用触媒は熱に対する耐性が低いことが知られている。The three-way catalyst is NO when the oxygen concentration is high.
It is known that the x purification function is low, and that the NOx purification catalyst has low resistance to heat.
【0004】したがって、エンジンが理論空燃比よりも
酸素含有量が高いリーンバーンで運転されているときの
ように排気ガス中の酸素濃度が高く且つNOxが多くな
る場合には、排気ガスをNOx浄化用触媒を通過させる
一方、理論空燃比近傍でエンジンが運転されているとき
のように、排気ガス中の酸素がリッチでなく且つ排気ガ
スの温度が高い場合には三元触媒を通過させている。Therefore, when the engine has a high oxygen concentration and a large amount of NOx in the exhaust gas, such as when the engine is operated in a lean burn mode in which the oxygen content is higher than the stoichiometric air-fuel ratio, the exhaust gas is purified with NOx. While passing through the catalyst for exhaust gas, the three-way catalyst is passed when oxygen in the exhaust gas is not rich and the temperature of the exhaust gas is high, as when the engine is operating near the stoichiometric air-fuel ratio. ..
【0005】このように排気ガスの状態に対応してNO
x浄化用触媒と三元触媒とを使い分けることを可能とす
るため特開平1−171625号公報に記載されている
ように、エンジンの排気ガスの温度を検知しその検知値
に基いて、排気ガス温度が低いときは排気ガスをNOx
浄化機能の大きい銅−ゼオライト触媒に導入し、排気ガ
ス温度が高いときは排気ガスを三元触媒に導入するよう
にした排気ガスの浄化技術が知られている。In this way, the NO
As described in Japanese Patent Laid-Open No. 1-171625, it is possible to selectively use a purification catalyst and a three-way catalyst, and the exhaust gas temperature is detected based on the detected temperature of the exhaust gas of the engine. When the temperature is low, exhaust gas is NOx
There is known a technique for purifying exhaust gas, which is introduced into a copper-zeolite catalyst having a large purification function and is introduced into a three-way catalyst when the exhaust gas temperature is high.
【0006】また、図8に示すように、エンジンaの排
気部に連結して設けられた第1の排気通路bに上流側か
ら下流側へNOx浄化用触媒cと三元触媒dとが順次設
けられており、上記第1の排気通路bのエンジン近傍か
ら分岐し上記NOx浄化用触媒cの下流側で上記三元触
媒dの上流側の合流部eにおいて上記第1の排気通路b
へ合流するように第2の排気通路fが設けられ、該第2
の排気通路fには三元触媒hが設けられており、排気ガ
スの流通経路は第1の排気通路bから第2の排気通路f
が分岐する部分に設けられたバルブgの切換えにより、
下記のように第1の排気通路b又は第2の排気通路fが
選択されるようになった排気ガス浄化装置が知られてい
る。すなわち、排気ガスが低温で且つ高酸素濃度である
ときには第1の排気通路bを流通してNOx浄化用触媒
cによりNOxが浄化された後三元触媒dによりCOと
HCとが浄化され、排気ガスが高温であるときには第2
の排気通路fを流通して上記NOx浄化用触媒cの下流
側の合流部eから上記第1の排気通路bに流入すること
により、第2の排気通路fに設けられた三元触媒h及び
第1の排気通路bに設けられた三元触媒dによってCO
とHCとNOxとが浄化されるようになっている。Further, as shown in FIG. 8, a NOx purifying catalyst c and a three-way catalyst d are sequentially arranged from an upstream side to a downstream side in a first exhaust passage b provided so as to be connected to an exhaust portion of an engine a. The first exhaust passage b is provided in a branch portion from the vicinity of the engine of the first exhaust passage b, and at the merging portion e on the downstream side of the NOx purification catalyst c and on the upstream side of the three-way catalyst d.
A second exhaust passage f is provided so as to join the
A three-way catalyst h is provided in the exhaust passage f of the exhaust gas, and the flow path of the exhaust gas is from the first exhaust passage b to the second exhaust passage f.
By switching the valve g provided in the part where
There is known an exhaust gas purification device in which the first exhaust passage b or the second exhaust passage f is selected as described below. That is, when the exhaust gas has a low temperature and a high oxygen concentration, the NOx purifying catalyst c purifies NOx after passing through the first exhaust passage b, and then the three-way catalyst d purifies CO and HC, Second when the gas is hot
Of the three-way catalyst h provided in the second exhaust passage f by flowing through the exhaust passage f of the NOx purifying catalyst c and flowing into the first exhaust passage b from the merging portion e on the downstream side of the NOx purification catalyst c. CO is generated by the three-way catalyst d provided in the first exhaust passage b.
And HC and NOx are purified.
【0007】[0007]
【発明が解決しようとする課題】しかしながら、上記し
た特開平1−171625号公報に記載されている浄化
技術により排気ガスを浄化しようとすれば、排気ガスが
高温の際には排気ガスは三元触媒に導入されて銅−ゼオ
ライト触媒に導入されることがないので、耐熱性の低い
上記銅−ゼオライト触媒を熱から保護し劣化を防止する
ことができる反面、排気ガスが低温の際には排気ガスは
銅−ゼオライト触媒に導入されて三元触媒に導入される
ことがないので、排気ガス中のNOxは十分に浄化され
るがHC及びCOは十分に浄化されないという問題点が
あった。However, if exhaust gas is to be purified by the purification technique described in Japanese Patent Laid-Open No. 1-171625, the exhaust gas will be ternary when the exhaust gas is at a high temperature. Since the copper-zeolite catalyst is not introduced into the catalyst and is not introduced into the catalyst, the copper-zeolite catalyst having low heat resistance can be protected from heat and deterioration can be prevented, while exhaust gas is exhausted when the temperature is low. Since the gas is introduced into the copper-zeolite catalyst and not into the three-way catalyst, there is a problem that NOx in the exhaust gas is sufficiently purified but HC and CO are not sufficiently purified.
【0008】また、図8に示す従来例の排気ガス浄化装
置では、排気ガスが高温であるときに第2の排気通路を
流通し第1の排気通路と第2の排気通路との合流部にお
いて第1の排気通路に流入した排気ガスは、上記第1の
排気通路内における上記合流部の上流側と下流側との間
にガス圧の差を生ぜしめることにより、高温の排気ガス
が上記合流部から第1の排気通路の上流側へ部分的に逆
流することが避けられない。その結果、上記合流部より
も上流側の第1の排気通路内に設けられているNOx浄
化用触媒が上記高温の排気ガスの熱により劣化するとい
う問題点があった。Further, in the conventional exhaust gas purifying apparatus shown in FIG. 8, when the exhaust gas is at a high temperature, it flows through the second exhaust passage and at the confluence of the first exhaust passage and the second exhaust passage. The exhaust gas that has flowed into the first exhaust passage causes a difference in gas pressure between the upstream side and the downstream side of the merging portion in the first exhaust passage, so that the high-temperature exhaust gas merges into the merging portion. It is inevitable that a partial reverse flow from the portion to the upstream side of the first exhaust passage will occur. As a result, there is a problem that the NOx purification catalyst provided in the first exhaust passage on the upstream side of the merging portion is deteriorated by the heat of the high-temperature exhaust gas.
【0009】上記に鑑みて、本発明は、第1の排気通路
と第2の排気通路との合流部に流入する第2の排気通路
を流通する高温の排気ガスを上記合流部よりも上流側の
第1の排気通路に設けられたNOx浄化用触媒に到達せ
しめないようにすることにより、NOx浄化用触媒を高
温の排気ガスの熱の影響から保護することを目的とす
る。In view of the above, according to the present invention, the high temperature exhaust gas flowing through the second exhaust passage flowing into the confluence portion of the first exhaust passage and the second exhaust passage is provided upstream of the confluence portion. It is an object of the present invention to protect the NOx purification catalyst from the influence of the heat of the high-temperature exhaust gas by preventing the NOx purification catalyst provided in the first exhaust passage from reaching the NOx purification catalyst.
【0010】[0010]
【課題を解決するための手段】上述したような目的を達
成するため、請求項1の発明は、第1の排気通路と第2
の排気通路との合流部において、第2の排気通路を流通
し第1の排気通路に流入する排気ガスを上記合流部より
も上流側の第1の排気通路へ逆流せしめないようにする
ものである。In order to achieve the above-mentioned object, the invention of claim 1 provides a first exhaust passage and a second exhaust passage.
The exhaust gas flowing through the second exhaust passage and flowing into the first exhaust passage at the merging portion with the exhaust passage is prevented from flowing backward to the first exhaust passage on the upstream side of the merging portion. is there.
【0011】具体的に、請求項1の発明の講じた解決手
段は、排気ガスが流通する第1の排気通路と、該第1の
排気通路に設けられたNOx浄化用触媒と、上記第1の
排気通路における上記NOx浄化用触媒の上流側から分
岐すると共に上記NOx浄化用触媒の下流側で合流し排
気ガスが流通する第2の排気通路と、該第2の排気通路
に設けられた三元触媒とを備えたエンジンの排気装置を
前提とし、上記第1の排気通路と上記第2の排気通路と
の合流部に、上記第2の排気通路を流通する排気ガスが
上記第1の排気通路の上流側に逆流するのを防止する逆
流防止部材が設けられている構成となっている。Specifically, the means for solving the problems of the first aspect of the invention is to provide a first exhaust passage through which exhaust gas flows, a NOx purification catalyst provided in the first exhaust passage, and the first exhaust passage. A second exhaust passage that branches from the upstream side of the NOx purification catalyst in the exhaust passage of the NOx and that joins on the downstream side of the NOx purification catalyst and through which the exhaust gas flows, and the three exhaust passages provided in the second exhaust passage. On the premise of an engine exhaust system including an original catalyst, the exhaust gas flowing through the second exhaust passage is at the confluence of the first exhaust passage and the second exhaust passage. A backflow prevention member for preventing backflow is provided on the upstream side of the passage.
【0012】また、請求項2の発明は、第1の排気通路
を流通する排気ガスは上記合流部よりも下流側へ流通可
能とする一方、第2の排気通路から第1の排気通路に流
入する排気ガスは第1の排気通路における上記合流部よ
りも下流側へ向って確実に流通させるものであって、具
体的には、請求項1の構成に、上記逆流防止部材は、上
記第1の排気通路を流通する排気ガスが上記合流部から
下流側へ流通するのを許容する一方、上記第2の排気通
路を流通する排気ガスが上記合流部から上記第1の排気
通路の上流側へ流通するのを阻止する逆止弁であるとい
う構成を付加するものである。According to the second aspect of the present invention, the exhaust gas flowing through the first exhaust passage can flow to the downstream side of the merging portion, while flowing from the second exhaust passage into the first exhaust passage. The exhaust gas to be circulated is surely circulated toward the downstream side of the merging portion in the first exhaust passage, and specifically, in the configuration of claim 1, the backflow preventing member is the first The exhaust gas flowing through the exhaust passage is allowed to flow from the joining portion to the downstream side, while the exhaust gas flowing through the second exhaust passage is passed from the joining portion to the upstream side of the first exhaust passage. It adds a configuration that is a check valve that blocks distribution.
【0013】また、請求項3の発明は、第1の排気通路
を排気ガスが流通するときに限りその排気ガスのガス圧
によって合流部よりも下流側の第1の排気通路に排気ガ
スが流通する流路が形成され、常時は第2の排気通路か
ら上記合流部よりも下流側の第1の排気通路へ排気ガス
が流通する流通路が形成されているようにするものであ
って、具体的には、請求項2の構成に、上記逆止弁は、
上記第1の排気通路の内部に設けられた弁座と、上記弁
座に密接するように付勢されている一方上記第1の排気
通路を流通する排気ガスのガス圧によって上記弁座との
間に排気ガスの流通路を形成する弁体とからなるという
構成を付加するものである。Further, according to the invention of claim 3, only when the exhaust gas flows through the first exhaust passage, the exhaust gas flows through the first exhaust passage on the downstream side of the merging portion due to the gas pressure of the exhaust gas. And a flow passage through which exhaust gas circulates from the second exhaust passage to the first exhaust passage on the downstream side of the merging portion is always formed. Specifically, in the structure of claim 2, the check valve is
Between the valve seat provided inside the first exhaust passage and the valve seat by the gas pressure of the exhaust gas flowing through the first exhaust passage while being urged so as to be in close contact with the valve seat. A configuration in which a valve body that forms a flow passage for exhaust gas is formed therebetween is added.
【0014】また、請求項4の発明は、第2の排気通路
を排気ガスが流通し第1の排気通路における合流部に流
入するときに、その排気ガスのガス圧によって上記合流
部において該合流部よりも下流側の第1の排気通路に上
記排気ガスが流通する流路が形成されるようにするもの
であって、具体的には、請求項2の構成に、上記逆止弁
は、上記第1の排気通路から上記合流部に流入する排気
ガスのガス圧によって下流側端部が上記第2の排気通路
側へ回動し、上記第2の排気通路から上記合流部に流入
する排気ガスのガス圧によって下流側端部が上記第1の
排気通路側へ回動するように軸支された回動板であると
いう構成を付加するものである。Further, according to the invention of claim 4, when the exhaust gas flows through the second exhaust passage and flows into the merging portion in the first exhaust passage, the merging portion is formed in the merging portion by the gas pressure of the exhaust gas. A flow passage through which the exhaust gas flows is formed in a first exhaust passage on the downstream side of the portion. Specifically, in the configuration of claim 2, the check valve includes: Exhaust gas that flows from the first exhaust passage into the merging portion due to the gas pressure of the exhaust gas flowing into the merging portion, and has its downstream end turned toward the second exhaust passage side. A configuration is added in which the downstream end is a rotating plate that is pivotally supported so as to rotate toward the first exhaust passage side by the gas pressure of the gas.
【0015】また、請求項5の発明は、第2の排気通路
から合流部に流入する排気ガスの流通方向を、第1の排
気通路における上記合流部よりも下流側に向ってガイド
するものであって、具体的には、請求項1の構成に、上
記逆流防止部材は、上記第2の排気通路から上記合流部
に流入する排気ガスが上記合流部から上記第1の排気通
路の下流側へ流通するようにガイドするガイド板である
という構成を付加するものである。Further, the invention of claim 5 guides the flow direction of the exhaust gas flowing from the second exhaust passage to the merging portion toward the downstream side of the merging portion in the first exhaust passage. Specifically, in the structure of claim 1, in the backflow prevention member, the exhaust gas flowing from the second exhaust passage into the merging portion is downstream from the merging portion in the first exhaust passage. The structure is a guide plate that guides the material to be distributed to the.
【0016】また、請求項6の発明は、第2の排気通路
を流通し合流部から第1の排気通路に流入した排気ガス
が、さらに三元触媒により浄化されるようにガイド板に
よってガイドしようとするものであって、具体的には、
請求項5の構成に、上記合流部よりも下流側の上記第1
の排気通路に三元触媒が設けられているという構成を付
加するものである。Further, in the invention of claim 6, the exhaust gas flowing through the second exhaust passage and flowing into the first exhaust passage from the merging portion is further guided by the guide plate so as to be further purified by the three-way catalyst. And specifically,
The structure according to claim 5, wherein the first portion on the downstream side of the merging portion
The configuration in which the three-way catalyst is provided in the exhaust passage of is added.
【0017】また、請求項7の発明は、第1の排気通路
を流通する排気ガスが第1の排気通路と第2の排気通路
との合流部よりも下流側へ流通するのを許容する一方、
上記第2の排気通路を流通し上記合流部から上記第1の
排気通路に流入する高温の排気ガスと上記合流部よりも
上流側に設けられているNOx浄化用触媒との間を熱的
に遮断しようとするものである。Further, according to the invention of claim 7, the exhaust gas flowing through the first exhaust passage is allowed to flow downstream of the confluence of the first exhaust passage and the second exhaust passage. ,
The high-temperature exhaust gas flowing through the second exhaust passage and flowing into the first exhaust passage from the confluence portion and the NOx purification catalyst provided upstream of the confluence portion are thermally provided. It is about to shut off.
【0018】具体的に、請求項7の発明が講じた解決手
段は、排気ガスが流通する第1の排気通路と、該第1の
排気通路に設けられたNOx浄化用触媒と、上記第1の
排気通路における上記NOx浄化用触媒の上流側から分
岐すると共に上記NOx浄化用触媒の下流側で合流し排
気ガスが流通する第2の排気通路と、該第2の排気通路
に設けられた三元触媒とを備えたエンジンの排気装置を
前提とし、上記第1の排気通路における該第1の排気通
路と上記第2の排気通路との合流部よりも上流側で且つ
上記NOx浄化用触媒の下流側に三元触媒が上記NOx
浄化用触媒と一体的に設けられている構成とするもので
ある。[0018] Specifically, the solution means taken by the invention of claim 7 is a first exhaust passage through which exhaust gas flows, a NOx purification catalyst provided in the first exhaust passage, and the first exhaust passage. A second exhaust passage that branches from the upstream side of the NOx purification catalyst in the exhaust passage of the NOx and that joins on the downstream side of the NOx purification catalyst and through which the exhaust gas flows, and the three exhaust passages provided in the second exhaust passage. On the premise of an engine exhaust system including a source catalyst, the NOx purification catalyst of the first exhaust passage upstream of the confluence of the first exhaust passage and the second exhaust passage The three-way catalyst on the downstream side is the NOx
It is configured to be provided integrally with the purification catalyst.
【0019】[0019]
【作用】請求項1の構成により、第1の排気通路と第2
の排気通路との合流部に上記第1の排気通路の上流側に
排気ガスの逆流するのを防止する逆流防止部材が設けら
れているため、第2の排気通路から第1の排気通路へ流
入する排気ガスは上記合流部よりも下流側の第1の排気
通路内を流通する。According to the structure of claim 1, the first exhaust passage and the second exhaust passage
Since a backflow preventing member for preventing backflow of exhaust gas is provided upstream of the first exhaust passage at a confluence portion with the exhaust passage, the second exhaust passage flows into the first exhaust passage. The exhaust gas that flows circulates in the first exhaust passage on the downstream side of the merging portion.
【0020】また、請求項2の構成により、上記逆流防
止部材は第1の排気通路の上流側から下流側へ向う流通
路を形成する逆止弁であるため、第1の排気通路を流通
する排気ガスは合流部よりも下流側へ支障なく流通する
一方、第2の排気通路から第1の排気通路における逆止
弁よりも下流側へ流入する排気ガスは第1の排気通路に
おける合流部よりも下流側へ向って流通する。Further, according to the second aspect of the invention, the backflow prevention member is a check valve that forms a flow passage from the upstream side to the downstream side of the first exhaust passage, and therefore flows through the first exhaust passage. The exhaust gas circulates downstream from the merging portion without any hindrance, while the exhaust gas flowing from the second exhaust passage to the downstream side of the check valve in the first exhaust passage passes from the merging portion in the first exhaust passage. Is also distributed downstream.
【0021】また、請求項3の構成により、上記逆止弁
は第1の排気通路の内部に設けられた弁座と上記弁座に
密接するように付勢されている弁体とよりなり、上記第
1の排気通路を流通する排気ガスのガス圧によってのみ
下流側への流通路が形成される逆止弁であるため、第2
の排気通路を流通する排気ガスは常に第1の排気通路に
おける合流部よりも下流側へのみ流通する。According to a third aspect of the present invention, the check valve comprises a valve seat provided inside the first exhaust passage and a valve element biased so as to come into close contact with the valve seat. Since it is a check valve in which the flow passage to the downstream side is formed only by the gas pressure of the exhaust gas flowing through the first exhaust passage,
Exhaust gas flowing through the exhaust passage always flows only to the downstream side of the merging portion in the first exhaust passage.
【0022】また、請求項4の構成により、上記逆止弁
は、第1の排気通路又は第2の排気通路を流通する排気
ガスのガス圧によって上記排気ガスを流通せしめる流通
路を形成する側に下流側の板体が回動するように軸支さ
れた回動板であるため、第2の排気通路を流通する排気
ガスが合流部に流入するときはそのガス圧によって上記
回動板は第1の排気通路側に回動し第1の排気通路を殆
んど閉じるので、第2の排気通路から上記合流部よりも
下流側の第1の排気通路へ向う流通路が形成される。According to the structure of claim 4, the check valve forms a flow passage through which the exhaust gas flows by the gas pressure of the exhaust gas flowing through the first exhaust passage or the second exhaust passage. Since the downstream plate body is a rotating plate that is pivotally supported so as to rotate, when the exhaust gas flowing through the second exhaust passage flows into the merging portion, the rotating plate causes the rotating plate to move. Since the first exhaust passage is rotated to the side of the first exhaust passage and the first exhaust passage is almost closed, a flow passage is formed from the second exhaust passage to the first exhaust passage downstream of the merging portion.
【0023】また、請求項5の構成により、上記逆流防
止部材は、第2の排気通路から合流部へ流入する排気ガ
スが上記合流部よりも下流側の第1の排気通路へ流通す
るように排気ガスの流通方向をガイドするガイド板であ
るため、第2の排気通路から合流部へ流入する排気ガス
は第1の排気通路における合流部よりも下流側へ向って
流通するようにガイドされる。According to a fifth aspect of the present invention, the backflow preventing member allows the exhaust gas flowing from the second exhaust passage to the merging portion to flow to the first exhaust passage downstream of the merging portion. Since the guide plate guides the flow direction of the exhaust gas, the exhaust gas flowing from the second exhaust passage to the merging portion is guided so as to flow toward the downstream side of the merging portion in the first exhaust passage. ..
【0024】また、請求項6の構成により、第1の排気
通路における合流部の下流側に三元触媒が設けられてい
るため、第2の排気通路を流通し上記合流部から第1の
排気通路へ流入した排気ガスは、上記合流部よりも下流
側に設けられた三元触媒に向って流通方向がガイドされ
る。Further, according to the sixth aspect of the present invention, since the three-way catalyst is provided on the downstream side of the merging portion in the first exhaust passage, the three-way catalyst flows through the second exhaust passage, and the first exhaust gas flows from the merging portion. The exhaust gas flowing into the passage is guided in the flow direction toward the three-way catalyst provided on the downstream side of the merging portion.
【0025】また、請求項7の構成により、第1の排気
通路における合流部よりも上流側であって且つNOx浄
化用触媒の下流側に、三元触媒が上記NOx浄化用触媒
と一体的に設けられているため、第2の排気通路を流通
し第1の排気通路と第2の排気通路との合流部から上記
第1の排気通路に流入する高温の排気ガスと上記合流部
よりも上流側の第1の排気通路内に設けられているNO
x浄化用触媒との間は熱的に遮断され、上記NOx浄化
用触媒は熱による影響から遮蔽される。According to the seventh aspect of the invention, the three-way catalyst is integrated with the NOx purification catalyst on the upstream side of the confluence portion in the first exhaust passage and on the downstream side of the NOx purification catalyst. Since it is provided, the high-temperature exhaust gas flowing through the second exhaust passage and flowing into the first exhaust passage from the joining portion of the first exhaust passage and the second exhaust passage is upstream of the joining portion. Provided in the first exhaust passage on the side
The NOx purification catalyst is thermally shielded from the x-purification catalyst, and the NOx purification catalyst is shielded from the influence of heat.
【0026】[0026]
【実施例】以下、本発明の実施例を図面に基づき説明す
る。Embodiments of the present invention will be described below with reference to the drawings.
【0027】(実施例1)図1に示すように、本発明に
係るエンジンの排気装置Aは、エンジン1の排気部に連
結されNOx浄化用触媒2が設けられた第1の排気通路
3を有しており、この第1の排気通路3内を低温の排気
ガスが流通する。また、第1の排気通路3に配設された
NOx浄化用触媒2の上流側に設けられた切換えバルブ
4により切換えられて分岐し高温の排気ガスが内部を流
通すると共に上記NOx浄化用触媒2の下流側の合流部
5において第1の排気通路3と合流する第2の排気通路
6を有しており、この第2の排気通路6には三元触媒7
が設けられている。さらに、第1の排気通路3と第2の
排気通路6との合流部5には、第2の排気通路6から流
入する高温の排気ガスが第1の排気通路3の上流側へ逆
流するのを防止する逆流防止部材8が設けられている。
また、合流部5よりも下流側の第1の排気通路3には下
流側三元触媒9が設けられている。(Embodiment 1) As shown in FIG. 1, an engine exhaust system A according to the present invention includes a first exhaust passage 3 connected to an exhaust portion of an engine 1 and provided with a NOx purification catalyst 2. The low temperature exhaust gas flows through the first exhaust passage 3. The NOx purifying catalyst 2 is switched and branched by a switching valve 4 provided on the upstream side of the NOx purifying catalyst 2 arranged in the first exhaust passage 3 so that high-temperature exhaust gas flows through the inside of the NOx purifying catalyst 2. Has a second exhaust passage 6 which merges with the first exhaust passage 3 in the downstream side of the merging portion 5, and the three-way catalyst 7 is provided in the second exhaust passage 6.
Is provided. Further, the high temperature exhaust gas flowing from the second exhaust passage 6 flows back to the upstream side of the first exhaust passage 3 at the confluence portion 5 of the first exhaust passage 3 and the second exhaust passage 6. A backflow prevention member 8 for preventing the above is provided.
Further, a downstream three-way catalyst 9 is provided in the first exhaust passage 3 downstream of the confluence portion 5.
【0028】この実施例1に係るエンジンの排気装置A
に設けられた逆流防止部材8は、第1の排気通路3を流
通する排気ガスが合流部5から下流側へ流通するのを許
容する一方、第2の排気通路6を流通する排気ガスが合
流部5から第1の排気通路3の上流側へ逆流するのを阻
止する逆止弁となっている。The engine exhaust system A according to the first embodiment
The backflow prevention member 8 provided in the above allows the exhaust gas flowing through the first exhaust passage 3 to flow downstream from the joining portion 5, while the exhaust gas flowing through the second exhaust passage 6 joins. It is a check valve that prevents reverse flow from the portion 5 to the upstream side of the first exhaust passage 3.
【0029】すなわち、図2に示すように、第1の排気
通路3と第2の排気通路6との合流部5に設けられる逆
止弁10Aは可動弁体を有する逆止弁であって、第1の
排気通路3の内壁面が弁座11に形成されており、この
弁座11に下流側から密接するようにメインスプリング
12により付勢される主弁体13が設けられている。さ
らに、主弁体13の軸線付近を切り抜いてセンター孔1
4aが設けられると共にこのセンター孔14aの周囲に
下流側から密接するようにメインスプリング12よりも
弱勢なサブスプリング14bにより付勢される副弁体1
4cが設けられ、これらによって副逆止弁14が形成さ
れている。That is, as shown in FIG. 2, the check valve 10A provided at the confluence portion 5 of the first exhaust passage 3 and the second exhaust passage 6 is a check valve having a movable valve body. The inner wall surface of the first exhaust passage 3 is formed in the valve seat 11, and the main valve body 13 biased by the main spring 12 is provided so as to closely contact the valve seat 11 from the downstream side. Further, cut out the vicinity of the axis of the main valve body 13 to cut the center hole 1
4a is provided and the sub-valve body 1 is biased by the sub-spring 14b which is weaker than the main spring 12 so as to closely contact the periphery of the center hole 14a from the downstream side.
4c is provided, and these form the sub check valve 14.
【0030】その結果、逆止弁10Aは副逆止弁14を
有する構成となっており、第1の排気通路3を流通する
排気ガスのガス圧が付加されないときは副弁体14cは
主弁体13に密接し主弁体13は弁座11に密接するた
め、逆止弁10Aは合流部5において第1の排気通路3
を閉止するので、第2の排気通路6から合流部5へ流入
する排気ガスは逆止弁10Aよりも下流側の第1の排気
通路3へ流通し、合流部5よりも上流側の第1の排気通
路3へ逆流することはない。As a result, the check valve 10A has the sub check valve 14, and when the gas pressure of the exhaust gas flowing through the first exhaust passage 3 is not applied, the sub valve body 14c is the main valve. Since the main valve body 13 is in close contact with the body 13 and the main valve body 13 is in close contact with the valve seat 11, the check valve 10 </ b> A is connected to the first exhaust passage 3 at the merging portion 5.
Since the exhaust gas flowing from the second exhaust passage 6 into the confluence portion 5 flows to the first exhaust passage 3 downstream of the check valve 10A, the exhaust gas flowing from the second exhaust passage 6 to the first exhaust passage 3 upstream of the confluence portion 5 is closed. There is no reverse flow to the exhaust passage 3.
【0031】この実施例1における逆止弁10Aは、第
1の排気通路3を流通する排気ガスのガス圧により先ず
副逆止弁14が開いて排気ガスが下流側へ流通し、排気
ガスのガス圧が増大すれば逆止弁10A全体において排
気ガスを下流側へ流通せしめる流通路を形成し、排気ガ
スの流通量の多少に応じて多段階の適当な流通路を形成
することができる。In the check valve 10A according to the first embodiment, the auxiliary check valve 14 is first opened by the gas pressure of the exhaust gas flowing through the first exhaust passage 3 so that the exhaust gas flows downstream and the exhaust gas If the gas pressure increases, a flow passage that allows exhaust gas to flow downstream can be formed in the entire check valve 10A, and appropriate multi-stage flow passages can be formed according to the amount of exhaust gas flowing.
【0032】尚、メインスプリング12の基部を支承す
るプレートの筒状壁部15には流通孔16が設けられて
おり、第1の排気通路3を流通する排気ガスが下流側へ
流通する流通路の一部となっている。A circulation hole 16 is provided in the cylindrical wall portion 15 of the plate that supports the base portion of the main spring 12, and a flow passage through which the exhaust gas flowing through the first exhaust passage 3 flows to the downstream side. Has become a part of.
【0033】(実施例2)この実施例2における逆流防
止部材8としての逆止弁10Bは図3に示すように、第
1の排気通路3と第2の排気通路6との合流部5に設け
られた回動板17となっている。(Second Embodiment) As shown in FIG. 3, a check valve 10B as a backflow preventing member 8 in the second embodiment is provided at a confluence portion 5 of a first exhaust passage 3 and a second exhaust passage 6. It is a rotating plate 17 provided.
【0034】この回動板17は、合流部5における第1
の排気通路3の内壁面において軸17aにより支持さ
れ、その下流側端部17bが第1の排気通路3側及び第
2の排気通路6側のうちのいずれかの側に向って回動可
能に設けられている。The rotating plate 17 is the first member in the merging section 5.
Is supported by the shaft 17a on the inner wall surface of the exhaust passage 3, and its downstream end 17b is rotatable toward either the first exhaust passage 3 side or the second exhaust passage 6 side. It is provided.
【0035】したがって、この実施例2における回動板
17よりなる逆止弁10Bでは、第1の排気通路3から
合流部5に流入する排気ガスのガス圧によって回動板1
7の下流側端部17bが第2の排気通路6側へ回動し、
一方、第2の排気通路6から合流部5に流入する排気ガ
スのガス圧によって回動板17の下流側端部17bが第
1の排気通路3側に回動する。これにより、第2の排気
通路6から合流部5に排気ガスが流入するときは回動板
17の下流側端部17bは第1の排気通路3側へ回動し
ているので、合流部5よりも下流側の第1の排気通路3
に排気ガスが流通する流通路が形成され、その流通路を
排気ガスが流通する。同時に第1の排気通路3は回動し
た回動板17の下流側端部17bにより殆んど閉じられ
るので、排気ガスが第1の排気通路3の合流部5よりも
上流側へ逆流することは阻止される。Therefore, in the check valve 10B including the rotating plate 17 according to the second embodiment, the rotating plate 1 is driven by the gas pressure of the exhaust gas flowing from the first exhaust passage 3 into the merging portion 5.
7 is rotated toward the second exhaust passage 6 side,
On the other hand, the downstream side end portion 17b of the rotating plate 17 rotates toward the first exhaust passage 3 side by the gas pressure of the exhaust gas flowing from the second exhaust passage 6 into the confluence portion 5. As a result, when the exhaust gas flows from the second exhaust passage 6 into the confluence portion 5, the downstream end 17b of the rotating plate 17 is rotated toward the first exhaust passage 3 side. First exhaust passage 3 on the downstream side of
A flow passage is formed in which the exhaust gas flows, and the exhaust gas flows through the flow passage. At the same time, the first exhaust passage 3 is almost closed by the downstream end portion 17b of the rotating rotary plate 17, so that the exhaust gas flows backward to the upstream side of the confluence portion 5 of the first exhaust passage 3. Is blocked.
【0036】(実施例3)この実施例3に係るエンジン
の排気装置Aに設けられた逆流防止部材8は、第2の排
気通路6から合流部5に流入する排気ガスが第1の排気
通路3における合流部5よりも下流側へ流通するように
ガイドするガイド板となっている。(Embodiment 3) In the backflow prevention member 8 provided in the exhaust system A of the engine according to Embodiment 3, the exhaust gas flowing from the second exhaust passage 6 into the confluence portion 5 has the first exhaust passage. 3 is a guide plate that guides the fluid to flow downstream of the confluence portion 5.
【0037】すなわち、図4に示すように、ガイド板1
8はガイド板本体18aを有し、ガイド板本体18aに
はガイド板本体18aの面から突出するように設けられ
排気ガスの流通をガイドするガイド部18bと、第1の
排気通路3を流通する排気ガスが合流部5よりも下流側
へ流通するのを許容する流通許容部18cとが設けられ
ている。この実施例3におけるガイド板18は、第1の
排気通路3の内部に挿入可能な形状の板状体よりなるガ
イド板本体18aと、このガイド板本体18aから、い
わゆる切り起しによって形成された複数個のガイド部1
8bと、ガイド部18bが切り起されて生じた孔によっ
て形成された流通許容部18cとを有している。That is, as shown in FIG. 4, the guide plate 1
Reference numeral 8 denotes a guide plate body 18a, which is provided in the guide plate body 18a so as to project from the surface of the guide plate body 18a, and a guide portion 18b which guides the flow of exhaust gas, and which flows through the first exhaust passage 3. A circulation permitting portion 18c that permits the exhaust gas to flow downstream of the confluence portion 5 is provided. The guide plate 18 in the third embodiment is formed by a guide plate main body 18a made of a plate-shaped body that can be inserted into the first exhaust passage 3 and a so-called cut-and-raised shape from the guide plate main body 18a. Multiple guide parts 1
8b and a flow permitting portion 18c formed by a hole formed by cutting and raising the guide portion 18b.
【0038】このようなガイド板18は、図5に示すよ
うに、第1の排気通路3における合流部5の上流側の内
壁面にガイド板18の一方の端部18dが接合するよう
に取付けられることにより、ガイド板18が合流部5に
おいて第1の排気通路3を横断するように設けられてい
る。As shown in FIG. 5, such a guide plate 18 is attached so that one end portion 18d of the guide plate 18 is joined to the inner wall surface of the first exhaust passage 3 on the upstream side of the merging portion 5. As a result, the guide plate 18 is provided so as to cross the first exhaust passage 3 at the confluence portion 5.
【0039】これにより、第2の排気通路6を流通し合
流部5へ流入する排気ガスは、ガイド板18のガイド部
18bによって流通がガイドされ第1の排気通路3にお
ける合流部5よりも下流側へ流通する。同時にガイド板
18に形成された流通許容部18cは、ガイド部18b
によって第2の排気通路6から流入する排気ガスから遮
蔽されることになるので、第2の排気通路6から合流部
5へ流入する排気ガスは合流部5よりも上流側の第1の
排気通路3へ逆流することはない。As a result, the exhaust gas flowing through the second exhaust passage 6 and flowing into the merging portion 5 is guided to flow by the guide portion 18b of the guide plate 18, and is downstream of the merging portion 5 in the first exhaust passage 3. Distribute to the side. At the same time, the flow permitting portion 18c formed on the guide plate 18 is connected to the guide portion 18b.
As a result, the exhaust gas flowing from the second exhaust passage 6 is shielded from the exhaust gas flowing in from the second exhaust passage 6, so that the exhaust gas flowing from the second exhaust passage 6 into the merging portion 5 is located upstream of the merging portion 5. There is no backflow to 3.
【0040】一方、第1の排気通路3を流通する排気ガ
スは合流部5においてガイド板18に設けられた流通許
容部18cを流通し、合流部5よりも下流側へ支障なく
流通する。On the other hand, the exhaust gas flowing through the first exhaust passage 3 flows through the flow permitting portion 18c provided on the guide plate 18 at the joining portion 5, and flows downstream from the joining portion 5 without any trouble.
【0041】(実施例4)この実施例4におけるエンジ
ンの排気装置Aも合流部に設けられる逆流防止部材8と
してガイド板が用いられている。すなわち、図6に示す
ように、上記実施例3におけるガイド板18と同様のガ
イド板18が第1の排気通路3と第2の排気通路6との
合流部5に同様に設けられている。(Embodiment 4) In the engine exhaust system A according to Embodiment 4, a guide plate is used as the backflow prevention member 8 provided at the confluence portion. That is, as shown in FIG. 6, a guide plate 18 similar to the guide plate 18 in the third embodiment is similarly provided in the confluence portion 5 of the first exhaust passage 3 and the second exhaust passage 6.
【0042】そして、エンジンの排気装置全体をコンパ
クトな形態にする意図のもとに、第1の排気通路3内に
設けられるガイド板18よりも上流側に位置するNOx
浄化用触媒2とガイド板18よりも下流側に位置する下
流側三元触媒9とを同軸状に設けた構成となっている。NOx located upstream of the guide plate 18 provided in the first exhaust passage 3 is intended to make the entire exhaust system of the engine compact.
The purification catalyst 2 and the downstream three-way catalyst 9 located downstream of the guide plate 18 are coaxially provided.
【0043】したがって、この実施例4においても合流
部5における第1の排気通路3内に、ガイド板本体18
aにガイド部18bと流通許容部18cとが形成された
ガイド板18が設けられているため、上記実施例3に示
すものと同様に第2の排気通路6から合流部5へ流入し
た排気ガスは第1の排気通路3における合流部5よりも
下流側へ流通がガイドされ、合流部5よりも上流側へ逆
流することはない。Therefore, also in the fourth embodiment, the guide plate main body 18 is provided in the first exhaust passage 3 in the merging portion 5.
Since the guide plate 18 in which the guide portion 18b and the flow permitting portion 18c are formed is provided in a, the exhaust gas flowing from the second exhaust passage 6 into the confluence portion 5 as in the third embodiment. The flow is guided to the downstream side of the merging portion 5 in the first exhaust passage 3, and does not flow back to the upstream side of the merging portion 5.
【0044】一方、第1の排気通路3を流通する排気ガ
スはガイド板18の上流側から下流側へ支障なく流通す
る。On the other hand, the exhaust gas flowing through the first exhaust passage 3 flows from the upstream side of the guide plate 18 to the downstream side without any trouble.
【0045】(実施例5)この実施例5におけるエンジ
ンの排気装置は、上記実施例1〜4におけるエンジンの
排気装置Aの合流部5に設けられた逆流防止部材8に代
えて、第1の排気通路3内における合流部5よりも上流
側であってNOx浄化用触媒2の下流側に断熱部材とし
て耐熱性に富む三元触媒を設けることにより、第2の排
気通路6から合流部5へ流入する高温の排気ガスとNO
x浄化用触媒2との間を熱的に遮断する構成となってい
る。(Embodiment 5) The engine exhaust system according to the fifth embodiment is replaced with the first backflow preventing member 8 provided at the confluence portion 5 of the engine exhaust system A according to the first to fourth embodiments. By providing a three-way catalyst having high heat resistance as a heat insulating member on the upstream side of the confluence portion 5 in the exhaust passage 3 and on the downstream side of the NOx purification catalyst 2, the second exhaust passage 6 moves to the confluence portion 5. Inflowing hot exhaust gas and NO
The x-purifying catalyst 2 is thermally isolated.
【0046】すなわち、図7に示すように、NOx浄化
用触媒が設けられた第1の排気通路3内において、第1
の排気通路3と第2の排気通路6との合流部5よりも上
流側で且つNOx浄化用触媒2の下流側に断熱用三元触
媒19が設けられている。That is, as shown in FIG. 7, in the first exhaust passage 3 in which the NOx purification catalyst is provided, the first
An adiabatic three-way catalyst 19 is provided upstream of the confluence 5 of the exhaust passage 3 and the second exhaust passage 6 and downstream of the NOx purification catalyst 2.
【0047】断熱用三元触媒19は別途得られる三元触
媒を用いてこれをNOx浄化用触媒2と合流部5との間
に配設してもよいが、この実施例5においては、例えば
コージェライト等よりなる触媒担体の全長の約3/4程
度の範囲の上流側にNOx浄化用成分をコーティングし
てNOx浄化用触媒2を形成し、無コーティング部20
を介して触媒担体の下流側にCO、HC及びNOx浄化
用成分をコーティングして断熱用三元触媒19を形成す
ることにより両触媒は一体的に設けられている。これに
より、NOx浄化用触媒2とその下流側に設けられる断
熱用三元触媒19とはコンパクトな形態に形成されてい
る。The adiabatic three-way catalyst 19 may be a separately obtained three-way catalyst and may be disposed between the NOx purification catalyst 2 and the merging portion 5. In the fifth embodiment, for example, A NOx purification catalyst 2 is formed by coating a NOx purification component on the upstream side within a range of about 3/4 of the entire length of a catalyst carrier made of cordierite or the like, and the uncoated portion 20
Both of the catalysts are integrally provided by coating the downstream side of the catalyst carrier with CO, HC and NOx purifying components through the to form the adiabatic three-way catalyst 19. As a result, the NOx purification catalyst 2 and the heat insulating three-way catalyst 19 provided on the downstream side thereof are formed in a compact form.
【0048】この実施例5におけるエンジンの排気装置
Aでは、第2の排気通路6を流通して合流部5から第1
の排気通路3内へ流入した高温の排気ガスは、合流部5
よりも上流側の第1の排気通路3へ一部が逆流するが、
合流部5から逆流した排気ガスはNOx浄化用触媒2の
下流側に設けられた断熱用三元触媒19に先ず接触す
る。しかし、三元触媒は本来耐熱性に富み900℃程度
の熱によって劣化することはないので、断熱用三元触媒
19は逆流して接触した排気ガスの熱により影響を受け
ることはない。さらに、逆流して断熱用三元触媒19に
接触した排気ガスはガス圧が低下するため、断熱用三元
触媒19の内部を上流側へ逆流する速度は微小となり、
内部を逆流する排気ガスのガス量は少くその温度は著し
く低下する。In the engine exhaust system A according to the fifth embodiment, the second exhaust passage 6 circulates through the second exhaust passage 6 to reach the first part from the merging part 5.
The high temperature exhaust gas flowing into the exhaust passage 3 of the
A part of the gas flows backward to the first exhaust passage 3 on the upstream side of
The exhaust gas flowing back from the merging portion 5 first comes into contact with the adiabatic three-way catalyst 19 provided on the downstream side of the NOx purification catalyst 2. However, since the three-way catalyst is originally highly heat resistant and is not deteriorated by heat of about 900 ° C., the adiabatic three-way catalyst 19 is not affected by the heat of the exhaust gas that flows back and contacts. Furthermore, since the exhaust gas that has flowed back and contacted with the adiabatic three-way catalyst 19 has a reduced gas pressure, the rate of reverse flow inside the adiabatic three-way catalyst 19 to the upstream side becomes minute,
The amount of exhaust gas flowing back inside is small, and its temperature drops significantly.
【0049】したがって、NOx浄化用触媒2は合流部
5から上流側へ逆流した排気ガスの熱から保護され劣化
することはない。同時に、第2の排気通路6から合流部
5へ流入した排気ガスの大部分は、合流部5よりも上流
側へ逆流した後還流した一部の排気ガスを随伴しつつ合
流部5よりも下流側へ流通する。Therefore, the NOx purification catalyst 2 is protected from the heat of the exhaust gas flowing back from the confluence portion 5 to the upstream side and is not deteriorated. At the same time, most of the exhaust gas flowing from the second exhaust passage 6 into the merging portion 5 flows back to the upstream side of the merging portion 5 and then returns to the downstream side of the merging portion 5 along with a part of the exhaust gas that has recirculated. Distribute to the side.
【0050】一方、第1の排気通路3を流通する排気ガ
スは、第1の排気通路3内に設けられたNOx浄化用触
媒2と断熱用三元触媒19とを順次通過し、合流部5よ
りも下流側へ流通することができる。On the other hand, the exhaust gas flowing through the first exhaust passage 3 successively passes through the NOx purifying catalyst 2 and the adiabatic three-way catalyst 19 provided in the first exhaust passage 3, and the confluent portion 5 Can be distributed downstream.
【0051】[0051]
【発明の効果】以上説明したように、請求項1の発明に
係るエンジンの排気装置によると、第1の排気通路と第
2の排気通路との合流部に逆流防止部材が設けられてい
ることにより、上記第2の排気通路から上記第1の排気
通路へ流入する排気ガスは、第1の排気通路における上
記合流部よりも上流側へ逆流することなく下流側へ流通
するため、第2の排気通路から上記合流部へ流入する排
気ガスが高温であるときに上記第1の排気通路における
上記合流部よりも上流側に設けられた熱に弱いNOx浄
化用触媒は高温の排気ガスの逆流により熱劣化すること
が防止される。As described above, according to the exhaust system for an engine of the first aspect of the present invention, the backflow prevention member is provided at the confluence of the first exhaust passage and the second exhaust passage. As a result, the exhaust gas flowing from the second exhaust passage into the first exhaust passage flows to the downstream side of the first exhaust passage without flowing backward to the upstream side of the merging portion. When the exhaust gas flowing from the exhaust passage to the merging portion is at a high temperature, the heat-sensitive NOx purification catalyst provided upstream of the merging portion in the first exhaust passage due to the backflow of the hot exhaust gas. Thermal deterioration is prevented.
【0052】また、請求項2の発明によると、逆流防止
部材は第1の排気通路の上流側から下流側へ向う流通路
のみを形成する逆止弁であるため、第1の排気通路を流
通する排気ガス及び第2の排気通路を流通し上記逆止弁
よりも下流側において上記第1の排気通路へ流入する排
気ガスはいずれも第1の排気通路における合流部よりも
下流側へ流通するので、合流部よりも上流側の第1の排
気通路への排気ガスの逆流は阻止される。Further, according to the second aspect of the present invention, since the backflow prevention member is a check valve that forms only a flow passage from the upstream side to the downstream side of the first exhaust passage, it flows through the first exhaust passage. Exhaust gas flowing through the second exhaust passage and the exhaust gas flowing into the first exhaust passage on the downstream side of the check valve flows on the downstream side of the merging portion of the first exhaust passage. Therefore, the backflow of the exhaust gas to the first exhaust passage on the upstream side of the merging portion is prevented.
【0053】また、請求項3の発明によると、逆止弁は
第1の排気通路を流通する排気ガスのガス圧によっての
み下流側への流通路が形成される逆止弁であるため、第
2の排気通路を流通する排気ガスは常に第1の排気通路
における合流部よりも下流側へのみ流通するので、合流
部よりも上流側の第1の排気通路への排気ガスの逆流は
確実に阻止される。According to the third aspect of the present invention, the check valve is a check valve in which the flow passage to the downstream side is formed only by the gas pressure of the exhaust gas flowing through the first exhaust passage. Since the exhaust gas flowing through the second exhaust passage always flows only to the downstream side of the joining portion in the first exhaust passage, the reverse flow of the exhaust gas to the first exhaust passage upstream of the joining portion is surely performed. Be blocked.
【0054】また、請求項4の発明によると、逆止弁は
第1の排気通路又は第2の排気通路を流通する排気ガス
のガス圧によってそれぞれの排気ガスの流通路を形成す
るように軸支された回動板であって、第2の排気通路を
流通する排気ガスが合流部に流入するときはそのガス圧
によって第2の排気通路から上記合流部よりも下流側の
第1の排気通路へ向う流通路が形成されるため、合流部
よりも上流側の第1の排気通路への排気ガスの逆流は確
実に阻止される。Further, according to the invention of claim 4, the check valve is configured such that the check valve forms a passage for each exhaust gas by the gas pressure of the exhaust gas flowing through the first exhaust passage or the second exhaust passage. When the exhaust gas flowing through the second exhaust passage flows into the merging portion, the rotating plate is supported by the first exhaust gas on the downstream side of the merging portion from the second exhaust passage due to the gas pressure thereof. Since the flow passage is formed toward the passage, the reverse flow of the exhaust gas to the first exhaust passage on the upstream side of the merging portion is reliably prevented.
【0055】また、請求項5の発明によると、逆流防止
部材は第2の排気通路から合流部へ流入する排気ガスが
上記合流部よりも下流側の第1の排気通路へ流通するよ
うにガイドするガイド板であるため、第2の排気通路か
ら合流部へ流入する排気ガスは第1の排気通路における
合流部よりも下流側へ向って流通するようにガイドされ
る。これにより、合流部よりも上流側の第1の排気通路
への排気ガスの逆流は阻止される。According to the fifth aspect of the present invention, the backflow prevention member guides the exhaust gas flowing from the second exhaust passage to the merging portion so as to flow to the first exhaust passage downstream of the merging portion. Since it is a guide plate, the exhaust gas flowing from the second exhaust passage to the merging portion is guided so as to flow toward the downstream side of the merging portion in the first exhaust passage. As a result, backflow of the exhaust gas to the first exhaust passage on the upstream side of the merging portion is prevented.
【0056】また、ガイド板は可動部分を持たないた
め、メンテナンスフリーの効果が併せ得られる。Further, since the guide plate has no moving parts, a maintenance-free effect can be obtained together.
【0057】また、請求項6の発明によると、第1の排
気通路における合流部の下流側に三元触媒が設けられて
おり、さらに、第2の排気通路を流通し上記合流部から
第1の排気通路へ流入した排気ガスは上記三元触媒に向
って流通するようにガイドされるため、第2の排気通路
から合流部に流入する排気ガスは合流部よりも上流側の
第1の排気通路内へ逆流することはない。Further, according to the invention of claim 6, a three-way catalyst is provided on the downstream side of the confluent portion in the first exhaust passage, and further, the three-way catalyst is circulated in the second exhaust passage to reach from the confluent portion to the first portion. Since the exhaust gas flowing into the exhaust passage of the first exhaust gas is guided so as to flow toward the three-way catalyst, the exhaust gas flowing from the second exhaust passage into the merging portion is the first exhaust gas on the upstream side of the merging portion. There is no backflow into the passage.
【0058】また、このような構成においては、第1の
排気通路内におけるガイド板の上流側に位置するNOx
浄化用触媒と下流側に位置する三元触媒とを同軸状に設
けることが容易となるので、エンジンの排気装置をコン
パクトな形態のものにすることが可能となる。Further, in such a structure, NOx located on the upstream side of the guide plate in the first exhaust passage.
Since it becomes easy to provide the purification catalyst and the three-way catalyst located on the downstream side coaxially, it becomes possible to make the exhaust system of the engine compact.
【0059】また、請求項7の発明に係るエンジンの排
気装置によると、第1の排気通路における合流部よりも
上流側でNOx浄化用触媒の下流側に三元触媒が上記N
Ox浄化用触媒と一体的に設けられているため、上記三
元触媒の有する耐熱性に富む特性により第2の排気通路
から合流部へ流入する高温の排気ガスと上記NOx浄化
用触媒との間は熱的に遮断される。これによりNOx浄
化用触媒は高温の排気ガスの逆流により熱劣化すること
が防止される。According to the engine exhaust system of the seventh aspect of the present invention, the three-way catalyst is the N-type catalyst which is upstream of the confluence portion in the first exhaust passage and downstream of the NOx purification catalyst.
Since it is provided integrally with the Ox purification catalyst, it is between the high temperature exhaust gas flowing from the second exhaust passage to the confluence and the NOx purification catalyst due to the heat-resistant characteristic of the three-way catalyst. Is thermally shut off. This prevents the NOx purification catalyst from thermally deteriorating due to the backflow of high-temperature exhaust gas.
【0060】また、熱の遮断に用いられる上記三元触媒
は排気ガスを浄化する機能も果すこともできる。Further, the above-mentioned three-way catalyst used for blocking heat can also have a function of purifying exhaust gas.
【図1】本発明に係るエンジンの排気装置の実施例を示
す断面図である。FIG. 1 is a sectional view showing an embodiment of an exhaust system for an engine according to the present invention.
【図2】本発明の実施例1における逆止弁を示す断面図
である。FIG. 2 is a sectional view showing a check valve according to the first embodiment of the present invention.
【図3】本発明の実施例2における回動板を示す断面図
である。FIG. 3 is a sectional view showing a rotating plate according to a second embodiment of the present invention.
【図4】本発明の実施例3及び実施例4において用いら
れるガイド板の斜視図である。FIG. 4 is a perspective view of a guide plate used in Examples 3 and 4 of the present invention.
【図5】本発明の実施例3におけるガイド板を示す断面
図である。FIG. 5 is a sectional view showing a guide plate according to a third embodiment of the present invention.
【図6】本発明の実施例4におけるガイド板を示す断面
図である。FIG. 6 is a sectional view showing a guide plate in Example 4 of the present invention.
【図7】本発明の実施例5における断熱用三元触媒を示
す断面図である。FIG. 7 is a sectional view showing a three-way catalyst for heat insulation in Example 5 of the present invention.
【図8】従来例を示す断面図である。FIG. 8 is a cross-sectional view showing a conventional example.
2 NOx浄化用触媒 3 第1の排気通路 4 切換えバルブ 5 合流部 6 第2の排気通路 7 三元触媒 8 逆流防止部材 9 下流側三元触媒 10A,10B 逆止弁 11 弁座 13 主弁体 14 副逆止弁 17 回動板 17a 回動板の下流側 18 ガイド板 18b ガイド部 18c 流通許容部 19 断熱用三元触媒 20 無コーティング部 2 NOx purification catalyst 3 First exhaust passage 4 Switching valve 5 Merging part 6 Second exhaust passage 7 Three-way catalyst 8 Backflow prevention member 9 Downstream three-way catalyst 10A, 10B Check valve 11 Valve seat 13 Main valve body 14 Sub check valve 17 Rotating plate 17a Downstream side of rotating plate 18 Guide plate 18b Guide portion 18c Flow permitting portion 19 Insulation three-way catalyst 20 Uncoated portion
───────────────────────────────────────────────────── フロントページの続き (72)発明者 廣田 智隆 広島県安芸郡府中町新地3番1号 マツダ 株式会社内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomotaka Hirota 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Motor Corporation
Claims (7)
該第1の排気通路に設けられたNOx浄化用触媒と、上
記第1の排気通路における上記NOx浄化用触媒の上流
側から分岐すると共に上記NOx浄化用触媒の下流側で
合流し排気ガスが流通する第2の排気通路と、該第2の
排気通路に設けられた三元触媒とを備えたエンジンの排
気装置において、上記第1の排気通路と上記第2の排気
通路との合流部に、上記第2の排気通路を流通する排気
ガスが上記第1の排気通路の上流側に逆流するのを防止
する逆流防止部材が設けられていることを特徴とするエ
ンジンの排気装置。1. A first exhaust passage through which exhaust gas flows,
The NOx purifying catalyst provided in the first exhaust passage and the NOx purifying catalyst in the first exhaust passage branch from the upstream side of the NOx purifying catalyst, and merge with the downstream side of the NOx purifying catalyst so that the exhaust gas flows. In an exhaust system of an engine including a second exhaust passage and a three-way catalyst provided in the second exhaust passage, in a confluence portion of the first exhaust passage and the second exhaust passage, An exhaust system for an engine, comprising: a backflow prevention member for preventing exhaust gas flowing through the second exhaust passage from flowing back to the upstream side of the first exhaust passage.
路を流通する排気ガスが上記合流部から下流側へ流通す
るのを許容する一方、上記第2の排気通路を流通する排
気ガスが上記合流部から上記第1の排気通路の上流側へ
流通するのを阻止する逆止弁であることを特徴とする請
求項1に記載のエンジンの排気装置。2. The backflow prevention member allows the exhaust gas flowing through the first exhaust passage to flow downstream from the merging portion, while the exhaust gas flowing through the second exhaust passage passes through the second exhaust passage. The exhaust device for an engine according to claim 1, wherein the check device is a check valve that blocks the flow from the merging portion to the upstream side of the first exhaust passage.
部に設けられた弁座と、上記弁座に密接するように付勢
されている一方上記第1の排気通路を流通する排気ガス
のガス圧によって上記弁座との間に排気ガスの流通路を
形成する弁体とからなることを特徴とする請求項2に記
載のエンジンの排気装置。3. The check valve is urged so as to come into close contact with a valve seat provided inside the first exhaust passage and the valve seat, and flows through the first exhaust passage. The exhaust system for an engine according to claim 2, further comprising: a valve body that forms a flow passage for the exhaust gas between the valve seat and the valve seat by the gas pressure of the exhaust gas.
上記合流部に流入する排気ガスのガス圧によって下流側
端部が上記第2の排気通路側へ回動し、上記第2の排気
通路から上記合流部に流入する排気ガスのガス圧によっ
て下流側端部が上記第1の排気通路側へ回動するように
軸支された回動板であることを特徴とする請求項2に記
載のエンジンの排気装置。4. The check valve has a downstream end turned to the second exhaust passage side by a gas pressure of exhaust gas flowing into the merging portion from the first exhaust passage, and the second end is rotated toward the second exhaust passage side. 7. The rotating plate pivotally supported so that the downstream end thereof is rotated toward the side of the first exhaust passage by the gas pressure of the exhaust gas flowing from the exhaust passage into the merging portion. 2. The engine exhaust system according to 2.
路から上記合流部に流入する排気ガスが上記合流部から
上記第1の排気通路の下流側へ流通するようにガイドす
るガイド板であることを特徴とする請求項1に記載のエ
ンジンの排気装置。5. The backflow prevention member is a guide plate that guides exhaust gas flowing from the second exhaust passage into the confluence portion so as to flow from the confluence portion to a downstream side of the first exhaust passage. The exhaust system for an engine according to claim 1, wherein the exhaust system is provided.
気通路に三元触媒が設けられていることを特徴とする請
求項5に記載のエンジンの排気装置。6. The exhaust system for an engine according to claim 5, wherein a three-way catalyst is provided in the first exhaust passage downstream of the merging portion.
該第1の排気通路に設けられたNOx浄化用触媒と、上
記第1の排気通路における上記NOx浄化用触媒の上流
側から分岐すると共に上記NOx浄化用触媒の下流側で
合流し排気ガスが流通する第2の排気通路と、該第2の
排気通路に設けられた三元触媒とを備えたエンジンの排
気装置において、上記第1の排気通路における該第1の
排気通路と上記第2の排気通路との合流部よりも上流側
で且つ上記NOx浄化用触媒の下流側に三元触媒が上記
NOx浄化用触媒と一体的に設けられていることを特徴
とするエンジンの排気装置。7. A first exhaust passage through which exhaust gas flows,
The NOx purifying catalyst provided in the first exhaust passage and the NOx purifying catalyst in the first exhaust passage branch from the upstream side of the NOx purifying catalyst, and merge with the downstream side of the NOx purifying catalyst so that the exhaust gas flows. An exhaust system for an engine, comprising: a second exhaust passage for controlling the exhaust gas; and a three-way catalyst provided in the second exhaust passage, the first exhaust passage and the second exhaust passage in the first exhaust passage. An exhaust system for an engine, wherein a three-way catalyst is provided integrally with the NOx purification catalyst on the upstream side of the confluence with the passage and on the downstream side of the NOx purification catalyst.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP4070982A JPH05272334A (en) | 1992-03-27 | 1992-03-27 | Engine exhaust device |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP4070982A JPH05272334A (en) | 1992-03-27 | 1992-03-27 | Engine exhaust device |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH05272334A true JPH05272334A (en) | 1993-10-19 |
Family
ID=13447247
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP4070982A Withdrawn JPH05272334A (en) | 1992-03-27 | 1992-03-27 | Engine exhaust device |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH05272334A (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6502391B1 (en) * | 1999-01-25 | 2003-01-07 | Toyota Jidosha Kabushiki Kaisha | Exhaust emission control device of internal combustion engine |
JP2007154810A (en) * | 2005-12-07 | 2007-06-21 | Nissan Motor Co Ltd | Catalyst degradation diagnosis device for internal combustion engine and diagnosis method |
JP2010071149A (en) * | 2008-09-17 | 2010-04-02 | Yanmar Co Ltd | Exhaust gas purifying device |
JP2017075578A (en) * | 2015-10-16 | 2017-04-20 | ヤンマー株式会社 | Exhaust emission control device for vessel |
JP2018119514A (en) * | 2017-01-27 | 2018-08-02 | ヤンマー株式会社 | Exhaust emission control device |
-
1992
- 1992-03-27 JP JP4070982A patent/JPH05272334A/en not_active Withdrawn
Cited By (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6502391B1 (en) * | 1999-01-25 | 2003-01-07 | Toyota Jidosha Kabushiki Kaisha | Exhaust emission control device of internal combustion engine |
JP2007154810A (en) * | 2005-12-07 | 2007-06-21 | Nissan Motor Co Ltd | Catalyst degradation diagnosis device for internal combustion engine and diagnosis method |
JP2010071149A (en) * | 2008-09-17 | 2010-04-02 | Yanmar Co Ltd | Exhaust gas purifying device |
CN108350781A (en) * | 2015-10-16 | 2018-07-31 | 洋马株式会社 | The waste gas purification apparatus of ship |
WO2017064877A1 (en) * | 2015-10-16 | 2017-04-20 | ヤンマー株式会社 | Exhaust gas purification device for ship |
KR20180030703A (en) * | 2015-10-16 | 2018-03-23 | 얀마 가부시키가이샤 | Exhaust gas purifier of ship |
JP2017075578A (en) * | 2015-10-16 | 2017-04-20 | ヤンマー株式会社 | Exhaust emission control device for vessel |
US20180340458A1 (en) * | 2015-10-16 | 2018-11-29 | Yanmar Co., Ltd. | Exhaust gas purification device for ship |
US10605144B2 (en) | 2015-10-16 | 2020-03-31 | Yanmar Co., Ltd. | Exhaust gas purification device for ship |
JP2018119514A (en) * | 2017-01-27 | 2018-08-02 | ヤンマー株式会社 | Exhaust emission control device |
WO2018139023A1 (en) * | 2017-01-27 | 2018-08-02 | ヤンマー株式会社 | Exhaust gas purification device |
KR20180135057A (en) * | 2017-01-27 | 2018-12-19 | 얀마 가부시키가이샤 | Exhaust gas purifier |
CN110249117A (en) * | 2017-01-27 | 2019-09-17 | 洋马株式会社 | Waste gas purification apparatus |
US10895188B2 (en) | 2017-01-27 | 2021-01-19 | Yanmar Power Technology Co., Ltd. | Exhaust gas purifier |
CN110249117B (en) * | 2017-01-27 | 2021-08-10 | 洋马动力科技有限公司 | Exhaust gas purification device |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 19990608 |