JP3194197B2 - Exhaust system for two-cycle engine - Google Patents
Exhaust system for two-cycle engineInfo
- Publication number
- JP3194197B2 JP3194197B2 JP18012091A JP18012091A JP3194197B2 JP 3194197 B2 JP3194197 B2 JP 3194197B2 JP 18012091 A JP18012091 A JP 18012091A JP 18012091 A JP18012091 A JP 18012091A JP 3194197 B2 JP3194197 B2 JP 3194197B2
- Authority
- JP
- Japan
- Prior art keywords
- exhaust
- exhaust pipe
- catalyst
- pipe passage
- low
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B75/00—Other engines
- F02B75/02—Engines characterised by their cycles, e.g. six-stroke
- F02B2075/022—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle
- F02B2075/025—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle two
Landscapes
- Characterised By The Charging Evacuation (AREA)
- Exhaust Gas After Treatment (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】この発明は、２サイクルエン
ジンの排気装置に係り、詳しくは低負荷、低速回転域で
の運転を改善する２サイクル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 a two-stroke engine, and more particularly to an exhaust system for a two-stroke engine which improves operation in a low-load, low-speed rotation range.
【０００２】[0002]
【従来の技術】特に、２サイクルエンジンは、低負荷、
低速回転域から高負荷、高速転域までの広範囲の運転領
域で、運転安定性が要求される。このような２サイクル
エンジンでは中高負荷、中高速回転域にエンジンチュー
ニングされると、低負荷、低速回転域では排気系にかか
る排気圧力の正圧、負圧が中高負荷、中高速回転域での
排気系にかかる排気圧力の正圧、負圧と逆になり、圧力
排気ガスの吹き抜けが生じたり、押し戻しが生じる等の
原因で運転が不安定になり、特に排気管の脈動による排
気圧力波の非同調低回転域で圧力が低下する現象が生じ
る。2. Description of the Related Art In particular, a two-cycle engine has a low load,
Operation stability is required in a wide operation range from a low speed rotation range to a high load and a high speed rotation range. In such a two-stroke engine, when the engine is tuned to a medium to high load and a medium to high speed rotation range, the positive pressure and the negative pressure of the exhaust pressure applied to the exhaust system in the low load and low speed rotation range are changed to a medium to high load and medium to high speed rotation range Exhaust pressure applied to the exhaust system is opposite to the positive pressure and negative pressure, and the operation becomes unstable due to the occurrence of blow-through of pressure exhaust gas or push-back, etc. A phenomenon occurs in which the pressure drops in the non-tuning low rotation range.
【０００３】[0003]
【発明が解決しようとする課題】このため、例えばエン
ジンの排気通路にエンジン回転数に応じて排気時期を変
化させる排気制御バルブを備え、中高負荷、中高速回転
域で排気制御バルブを開いて排気時期を進めて排気ガス
の排出を早め、一方低負荷、低速回転域では排気制御バ
ルブを閉じて排気時期を遅らせるものがある。For this reason, for example, an exhaust control valve for changing the exhaust timing in accordance with the engine speed is provided in the exhaust passage of the engine, and the exhaust control valve is opened in the middle and high load and middle and high speed rotation ranges to open the exhaust control valve. In some cases, the exhaust gas is expedited by advancing the timing, while the exhaust timing is delayed by closing the exhaust control valve in a low-load, low-speed rotation range.
【０００４】ところで、アイドル近傍の低負荷、低速回
転域でも排気制御バルブを開いて排気時期を進めると、
燃焼室の排気ガスを早く出すことができ、燃焼室での燃
料の入換えがスムーズになり、しかも爆発でのピストン
の下りのとき排気ガスを早く排出することでポンピング
ロスが少なくなり好ましい。By the way, when the exhaust control valve is opened to advance the exhaust timing even in a low-load and low-speed rotation range near the idling,
It is preferable that the exhaust gas of the combustion chamber can be quickly discharged, the fuel exchange in the combustion chamber can be smoothly performed, and the exhaust gas is quickly discharged when the piston goes down due to the explosion, so that the pumping loss is reduced.
【０００５】しかし、低負荷、低速回転域で、排気制御
バルブを開いて排気時期を進めると、エンジンチューニ
ングの関係上、前記したような排気ガスの吹き抜けが生
じたり、押し戻しが生じる等の原因で運転が不安定にな
る等の問題がある。However, if the exhaust control valve is opened and the exhaust timing is advanced in a low-load, low-speed rotation range, due to the engine tuning, the exhaust gas may blow through or push back as described above. There are problems such as unstable driving.
【０００６】この発明はこのような実状に鑑みてなされ
たもので、装置を複雑化することなく、低負荷、低速回
転域での運転の出力及び安定性を向上させるエンジンの
排気装置を提供することを目的としている。The present invention has been made in view of such circumstances, and provides an engine exhaust device that improves the output and stability of operation in a low-load, low-speed rotation range without complicating the device. It is intended to be.
【０００７】[0007]
【課題を解決するための手段】前記課題を解決するた
め、請求項１記載の２サイクルエンジンの排気装置の発
明は、エンジンの排気通路にエンジン回転数に応じて排
気時期を変化させる排気制御バルブを備えるとともに、
前記排気通路に接続した排気管の排気管通路に設けた触
媒ハウジングの一部にチャンバを形成し、この触媒ハウ
ジングの内部に取付フレームを移動可能に取り付け、こ
の取付フレームに前記排気管通路の一部をなす枠部を一
対並設し、一方の枠部内に可動触媒を取付け、他方の枠
部内を空にし、前記取付けフレームは、前記可動触媒が
前記排気管通路に位置したとき前記空の枠部が前記排気
管通路より退却し、前記チャンバを前記排気管通路に連
通するとともに、前記空の枠部が前記排気管通路に位置
したとき前記可動触媒が前記排気管通路より退却し、前
記チャンバを遮断し排気が前記空の枠部内を通過するよ
う動作して連通バルブを構成し、低負荷、低速回転域で
前記排気制御バルブを開くとともに前記可動触媒を排気
管通路に進出し、この排気管通路を前記チャンバに連通
させたことを特徴としている。According to a first aspect of the present invention, there is provided an exhaust system for a two-stroke engine, wherein an exhaust timing is changed in an exhaust passage of the engine in accordance with an engine speed. With
A chamber is formed in a part of a catalyst housing provided in an exhaust pipe passage of an exhaust pipe connected to the exhaust passage, and a mounting frame is movably mounted inside the catalyst housing, and one of the exhaust pipe passages is mounted on the mounting frame. A pair of frame portions forming a part is arranged side by side, a movable catalyst is mounted in one frame portion, and the inside of the other frame portion is emptied, the mounting frame is an empty frame when the movable catalyst is located in the exhaust pipe passage. Section retreats from the exhaust pipe passage, communicates the chamber with the exhaust pipe passage, and when the empty frame is located in the exhaust pipe passage, the movable catalyst retreats from the exhaust pipe passage, and the chamber To shut off the exhaust gas to pass through the empty frame to form a communication valve, open the exhaust control valve in a low load, low speed rotation range and advance the movable catalyst into the exhaust pipe passage, The exhaust pipe passage is characterized in that communicates with the said chamber.
【０００８】この請求項１記載の発明では、エンジンの
低負荷、低速回転域で排気制御バルブを開くとともに、
チャンバを排気管通路と連通させるから、排気管の脈動
による排気負圧をチャンバで減少させ、体積効率低下を
防止し、希薄空燃費での運転性を向上させることができ
る。しかも、低負荷、低速回転域で排気時期を進めて、
圧縮圧力を軽減し、運転を安定させることができる。According to the first aspect of the present invention, the exhaust control valve is opened when the engine is in a low-load, low-speed rotation range.
Since the chamber communicates with the exhaust pipe passage, the exhaust negative pressure due to the pulsation of the exhaust pipe can be reduced in the chamber, the volume efficiency can be prevented from lowering, and the operability with lean air-fuel efficiency can be improved. In addition, advance the exhaust timing at low load and low speed rotation range,
The compression pressure can be reduced and the operation can be stabilized.
【０００９】また、低負荷、低速回転域で可動触媒を排
気管通路に進出させるから、触媒活性を促進して排気浄
化を向上できる。一方、高負荷時、後退させることがで
きるので触煤の過熟を防ぎ耐久性を増大できる。Further, since the movable catalyst advances into the exhaust pipe passage in a low-load, low-speed rotation range, the catalytic activity can be promoted to improve the purification of exhaust gas. On the other hand, when the load is high, it can be retracted, so that the soot can be prevented from being overripened and the durability can be increased.
【００１０】また、触媒を進退させるための部材である
取付フレームを有効に利用し、連通バルブを構成させる
ので、連通バルブを特別に設ける必要がなくなり装置の
複雑化を防ぐことができる。Further, since the communication valve is formed by effectively using the mounting frame which is a member for moving the catalyst forward and backward, it is not necessary to provide a special communication valve, and the apparatus can be prevented from becoming complicated.
【００１１】[0011]
【実施例】次に、この発明の実施例を添付図面に基づい
て詳細に説明する。Next, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
【００１２】図１はエンジンの排気装置の断面図、図２
はエンジンの排気装置の要部の拡大図、図３は低負荷及
び低速回転域における可動触媒の作動位置を示す図、図
４は高負荷時及び高速回転域における可動触媒の作動位
置を示す図、図５はチャンバ開閉及び排気制御バルブ開
閉とエンジン回転数との関係を示す図である。筒内噴射
式２サイクルエンジン１は、クランクケース２上にシリ
ンダボディ３及びシリンダヘッド４を載置して締結し、
このシリンダヘッド４に点火プラグ５及び空気燃料噴射
装置６を備えた構造である。FIG. 1 is a sectional view of an exhaust system of an engine, and FIG.
FIG. 3 is an enlarged view of a main part of the exhaust device of the engine, FIG. 3 is a diagram showing an operating position of the movable catalyst in a low load and low speed rotation range, and FIG. FIG. 5 is a diagram showing the relationship between the opening and closing of the chamber and the opening and closing of the exhaust control valve and the engine speed. The in-cylinder injection two-cycle engine 1 mounts and fastens a cylinder body 3 and a cylinder head 4 on a crankcase 2,
The cylinder head 4 is provided with a spark plug 5 and an air fuel injection device 6.
【００１３】シリンダボディ３内にはシリンダライナ７
が挿入され、このシリンダライナ７内にはピストン８が
摺動自在に設けられている。このピストン８にはコンロ
ッド９の小端部９ａがピストンピン１０で連結され、こ
のコンロッド９の大端部９ｂはクランク軸１１のクラン
クアーム１２にクランクピン１３で連結されている。ま
た、クランクアーム１２はクランクケース２のクランク
室１４内に収容されており、このクランク室１４はシリ
ンダボディ３に形成された掃気通路１５を介してシリン
ダライナ７の中程に開口した掃気ポート７ａに連通して
いる。A cylinder liner 7 is provided in the cylinder body 3.
The piston 8 is slidably provided in the cylinder liner 7. A small end 9a of a connecting rod 9 is connected to the piston 8 by a piston pin 10, and a large end 9b of the connecting rod 9 is connected to a crank arm 12 of a crank shaft 11 by a crank pin 13. The crank arm 12 is accommodated in a crank chamber 14 of the crank case 2, and the crank chamber 14 is provided with a scavenging port 7 a which is opened in the middle of the cylinder liner 7 through a scavenging passage 15 formed in the cylinder body 3. Is in communication with
【００１４】掃気通路１５の下方位置のクランクケース
２にはクランク室１４に連通する吸気通路１６が形成さ
れており、この吸気通路１６にはリード弁１７がジョイ
ント１８と共締めによって装着されている。このリード
弁１７は導入口１９ａが形成された弁座１９と、導入口
１９ａを開閉するばね剛板製の弁板２０と、この弁板２
０の開度を規制するストッパ２１とから構成されてい
る。また、ジョイント１８にはスロットル弁２２を有す
るスロットルボディ２３が接続されている。An intake passage 16 communicating with the crank chamber 14 is formed in the crankcase 2 below the scavenging passage 15, and a reed valve 17 is mounted in the intake passage 16 by jointly fastening with a joint 18. . The reed valve 17 includes a valve seat 19 having an inlet 19 a formed therein, a valve plate 20 made of a spring rigid plate for opening and closing the inlet 19 a, and a valve plate 2.
And a stopper 21 that regulates the opening degree of zero. Further, a throttle body 23 having a throttle valve 22 is connected to the joint 18.
【００１５】シリンダボディ３のシリンダライナ７には
掃気ポート７ａと対向する位置に排気ポート７ｂが形成
され、この排気ポート７ｂはシリンダボディ３の排気通
路２４に連通している。排気通路２４には排気ポート７
ｂの近傍に排気制御バルブ２５が回動自在に配設されて
おり、この排気制御バルブ２５は排気ポート７ｂの上縁
位置を変化させることによって排気時期を制御する。An exhaust port 7b is formed in the cylinder liner 7 of the cylinder body 3 at a position facing the scavenging port 7a, and the exhaust port 7b communicates with an exhaust passage 24 of the cylinder body 3. An exhaust port 7 is provided in the exhaust passage 24.
An exhaust control valve 25 is rotatably disposed near b, and the exhaust control valve 25 controls the exhaust timing by changing the upper edge position of the exhaust port 7b.
【００１６】シリンダボディ３の排気通路２４には排気
管２６が接続され、この排気管２６は可動触媒部２７、
マフラ部２８及びサイレンサ部２９からなっている。マ
フラ部２９の後部には固定触媒３０が設けられ、排気管
下流側通路に位置しており、排気は固定触媒３０を通っ
てサイレンサ部２９に導かれる。An exhaust pipe 26 is connected to the exhaust passage 24 of the cylinder body 3.
It comprises a muffler section 28 and a silencer section 29. A fixed catalyst 30 is provided at a rear portion of the muffler section 29 and is located in a downstream passage of an exhaust pipe. Exhaust gas is guided to the silencer section 29 through the fixed catalyst 30.
【００１７】可動触媒部２７は触媒ハウジングを構成す
る分割触媒ハウジング３１，３２が接合固定され、この
分割触媒ハウジング３１はシリンダボディ３側に接続さ
れ、分割触媒ハウジング３２はマフラ部２８側に接続さ
れている。The movable catalyst portion 27 is fixedly joined to divided catalyst housings 31 and 32 constituting a catalyst housing. The divided catalyst housing 31 is connected to the cylinder body 3 side, and the divided catalyst housing 32 is connected to the muffler portion 28 side. ing.
【００１８】この分割触媒ハウジング３１，３２でチャ
ンバ３３が形成されている。このチャンバ３３は分割触
媒ハウジング３１，３２の一部を外方へ延出して形成さ
れ、分割触媒ハウジング３１に形成されたガイド壁３１
ａで、排気ガスを排気管通路３４の上流側３４ａから開
口部３３ａを介してチャンバ３３側へ流す流路が形成さ
れる。A chamber 33 is formed by the divided catalyst housings 31 and 32. The chamber 33 is formed by extending a part of the divided catalyst housings 31 and 32 outward, and a guide wall 31 formed in the divided catalyst housing 31 is formed.
In a, a flow path is formed in which the exhaust gas flows from the upstream side 34a of the exhaust pipe passage 34 to the chamber 33 through the opening 33a.
【００１９】可動触媒部２７の分割触媒ハウジング３
１，３２には回転軸３５が支持され、この回転軸３５に
取付フレーム３６がキー３７で取付られ、取付フレーム
３６は回転軸３５と一体に回転可能になっている。この
取付フレーム３６には分割触媒ハウジング３１，３２の
排気管通路３４と同径の一対の枠部３６ａ，３６ｂが形
成され、一方の枠部３６ａに可動触媒３８が取付られ、
他方の枠部３６ｂは空になっている。可動触媒３８が取
付られた枠部３６ａには切欠部３６ｃが形成されてお
り、この切欠部３６ｃはチャンバ３３の開口部３３ａと
対向し、可動触媒３８が排気管通路３４に位置するとき
に、開口部３３ａを介して排気管通路３４とチャンバ３
３を連通し、取付フレーム３６が連通バルブを構成して
いる。The divided catalyst housing 3 of the movable catalyst section 27
A rotation shaft 35 is supported on the rotation shafts 1, 32, and a mounting frame 36 is mounted on the rotation shaft 35 with a key 37, and the mounting frame 36 can rotate integrally with the rotation shaft 35. A pair of frame portions 36a and 36b having the same diameter as the exhaust pipe passage 34 of the split catalyst housings 31 and 32 are formed on the mounting frame 36, and the movable catalyst 38 is mounted on one of the frame portions 36a.
The other frame portion 36b is empty. A cutout portion 36c is formed in the frame portion 36a to which the movable catalyst 38 is attached. The cutout portion 36c faces the opening 33a of the chamber 33, and when the movable catalyst 38 is located in the exhaust pipe passage 34, The exhaust pipe passage 34 and the chamber 3 are opened through the opening 33a.
3 and the mounting frame 36 constitutes a communication valve.
【００２０】取付フレーム３６は回転軸３５の回動で作
動し、可動触媒３８が排気管通路３４に位置したとき空
の枠部３６ｂが排気管通路３４より退却し、チャンバ３
３を排気管通路３４に連通するとともに、空の枠部３６
ｂが排気管通路３４に位置したとき可動触媒３８が排気
管通路３４より退却し、チャンバ３３を遮断し排気が空
の枠部３６ｂ内を通過するようになっている。The mounting frame 36 is operated by the rotation of the rotating shaft 35. When the movable catalyst 38 is located in the exhaust pipe passage 34, the empty frame portion 36b retreats from the exhaust pipe passage 34, and the chamber 3
3 communicates with the exhaust pipe passage 34 and an empty frame 36
When b is located in the exhaust pipe passage 34, the movable catalyst 38 retreats from the exhaust pipe passage 34, shuts off the chamber 33, and the exhaust gas passes through the empty frame portion 36b.
【００２１】可動触媒部２７の回転軸３５にはプーリ３
９が設けられ、このプーリ３９に取付られたワイヤ４
０，４１がサーボモータ４２に接続され、このサーボモ
ータ４２は制御装置４３で制御される。制御装置４３に
はスロットル開度検出手段４４、排気バルブ開度検出手
段４５、排気温度検出手段４６及びエンジン回転数検出
手段４７からの情報が入力されており、これらの情報に
よるエンジン運転状態からサーボモータ４２を制御し
て、可動触媒３８をエンジン運転状態に応じて排気管上
流側通路から退却可能としている。The pulley 3 is mounted on the rotating shaft 35 of the movable catalyst unit 27.
9 is provided, and the wire 4 attached to the pulley 39 is provided.
0 and 41 are connected to a servomotor 42, which is controlled by a controller 43. The control device 43 receives information from the throttle opening detecting means 44, the exhaust valve opening detecting means 45, the exhaust temperature detecting means 46, and the engine speed detecting means 47. The motor 42 is controlled so that the movable catalyst 38 can retreat from the exhaust pipe upstream passage in accordance with the engine operating state.
【００２２】なお、排気温度検出手段４６は可動触媒３
８の近傍上流側に設けているが、可動触媒３８の近傍下
流側に設けてもよく、或いは固定触媒３０の近傍上流側
に設けてもよい。また、可動触媒３８及び固定触媒３０
は例えばモノリス触媒、セラミック触媒、布状触媒等が
用いられるが、特に限定されず種々の触媒を用いること
ができ、また可動触媒３８及び固定触媒３０で異なる触
媒を用いることもでき、この場合可動触媒３８には耐熱
性を有する触媒を用いることが好ましい。It should be noted that the exhaust temperature detection means 46 is
8, it may be provided on the downstream side near the movable catalyst 38, or may be provided on the upstream side near the fixed catalyst 30. Further, the movable catalyst 38 and the fixed catalyst 30
For example, a monolith catalyst, a ceramic catalyst, a cloth catalyst, or the like is used, but not particularly limited, various catalysts can be used, and different catalysts can be used for the movable catalyst 38 and the fixed catalyst 30. It is preferable to use a catalyst having heat resistance as the catalyst 38.
【００２３】このエンジンの排気装置では、スロットル
開度検出手段４４、排気バルブ開度検出手段４５、排気
温度検出手段４６及びエンジン回転数検出手段４７から
の情報により、制御装置４３で、エンジン運転状態を例
えば低負荷または低速回転域、或いは低温始動時の判断
が行なわれると、サーボモータ４２を制御して可動触媒
３８を排気管通路３４に位置させる。これにより、シリ
ンダボディ３の排気管通路２４を出た直後の排気は高温
であるため、可動触媒３８は速かに活性化温度に上昇し
て、その浄化による発熱によって排気はさらに高温にな
り、さらに固定触媒３０で浄化する。In the exhaust system of this engine, the control device 43 uses the information from the throttle opening detecting means 44, the exhaust valve opening detecting means 45, the exhaust temperature detecting means 46 and the engine speed detecting means 47 to control the engine operating state. When a determination is made, for example, in a low-load or low-speed rotation region or at a low-temperature start, the servomotor 42 is controlled to position the movable catalyst 38 in the exhaust pipe passage 34. As a result, since the exhaust gas immediately after exiting the exhaust pipe passage 24 of the cylinder body 3 has a high temperature, the movable catalyst 38 quickly rises to the activation temperature, and the heat generated by the purification causes the exhaust gas to have a higher temperature. Further, the catalyst is purified by the fixed catalyst 30.
【００２４】一方、制御装置４３で、例えば高負荷また
は高速回転域の判断が行なわれると、サーボモータ４２
を制御して回転軸３５を回転させると、取付フレーム３
６に設けられた可動触媒３８が排気管通路３４から退却
し、可動触媒３８が過熱することがないようにして、固
定触媒３０のみで浄化させる。従って、高負荷または高
回転域で、可動触媒３８が熱による影響を受けないよう
にして耐久性を増大させている。On the other hand, when the controller 43 determines, for example, a high load or a high speed rotation range, the servo motor 42
Is controlled to rotate the rotating shaft 35, the mounting frame 3
The movable catalyst 38 provided in 6 is retreated from the exhaust pipe passage 34 and the movable catalyst 38 is purified only by the fixed catalyst 30 so as not to be overheated. Therefore, the durability is increased by preventing the movable catalyst 38 from being affected by heat under a high load or a high rotation range.
【００２５】次に、この実施例の作動を説明する。エン
ジンの運転で、排気制御バルブ２５及び可動触媒３８は
図５に示すように作動する。エンジンはアイドル近傍で
稀薄空燃比で運転され、このエンジンの低負荷、低速回
転域Ｎ１で排気制御バルブ２５を開くとともに、可動触
媒３８を排気管通路３４に進出させてチャンバ３３をと
連通させる。そして、可動触媒３８を排気管通路３４に
進出させたままで、所定のエンジン回転数域Ｎ２で排気
制御バルブ２５を閉じて、さらに所定の中高負荷、中高
速回転域Ｎ３のエンジン回転数で排気制御バルブ２５を
開き、また、この中高負荷、中高速回転域Ｎ３で可動触
媒３８を排気管通路３４から退去させる。Next, the operation of this embodiment will be described. During operation of the engine, the exhaust control valve 25 and the movable catalyst 38 operate as shown in FIG. The engine is operated at a lean air-fuel ratio near idle and opens the exhaust control valve 25 in the low-load, low-speed rotation range N1 of the engine, and moves the movable catalyst 38 into the exhaust pipe passage 34 to communicate the chamber 33 with the engine. The exhaust control valve 25 is closed in a predetermined engine speed range N2 with the movable catalyst 38 advanced into the exhaust pipe passage 34, and the exhaust control is further performed in an engine speed in a predetermined medium-high load, medium-high speed range N3. The valve 25 is opened, and the movable catalyst 38 is retreated from the exhaust pipe passage 34 in the medium-high load, medium-high speed rotation range N3.
【００２６】このように、エンジン回転数に応じて排気
時期を変化させる排気制御バルブ２５は、中高負荷、中
高速回転域Ｎ３で開いて排気時期を進めるため、排気ガ
スの排出を早めることができ、一方低負荷、低速回転域
Ｎ１でも排気制御バルブ２５を開いて排気時期を進めて
いる。このアイドル近傍の低負荷、低速回転域Ｎ１で排
気制御バルブ２５を開いて排気時期を進めることによ
り、燃焼室の排気ガスを早く出すことができ、燃焼室で
の燃料の入換えがスムーズになり、しかも爆発でのピス
トンの下りのとき排気ガスを早く排出することでポンピ
ングロスが少なくなり好ましい。As described above, since the exhaust control valve 25 that changes the exhaust timing in accordance with the engine speed is opened in the medium-high load, medium-high speed rotation range N3 to advance the exhaust timing, the exhaust gas can be discharged earlier. On the other hand, the exhaust timing is advanced by opening the exhaust control valve 25 even in the low load and low speed rotation range N1. By opening the exhaust control valve 25 in the low-load, low-speed rotation range N1 near the idle to advance the exhaust timing, the exhaust gas in the combustion chamber can be quickly discharged, and the fuel exchange in the combustion chamber becomes smooth. In addition, when the piston goes down due to the explosion, the exhaust gas is quickly discharged, so that the pumping loss is reduced, which is preferable.
【００２７】しかも、このとき、エンジンの低負荷、低
速回転域Ｎ１に排気制御バルブ２５を開くとともに、可
動触媒３８を排気管通路３４に位置させ、チャンバ３３
を排気管通路３４に連通させており、排気負圧をチャン
バ３３で軽減することで、体積効率低下を防止し、稀薄
空燃比運転での運転性を向上させる。しかも、低負荷、
低速回転域Ｎ１で排気時期を進めて、燃焼室の排気ガス
を早く出して、燃料の入換えをスムーズにしており、圧
縮圧力を軽減し、運転を安定し、稀薄空燃比での運転を
可能にする。In addition, at this time, the exhaust control valve 25 is opened in the low-load, low-speed rotation range N1 of the engine, and the movable catalyst 38 is located in the exhaust pipe passage 34, so that the chamber 33
Is communicated with the exhaust pipe passage 34, and by reducing the exhaust negative pressure in the chamber 33, a decrease in volumetric efficiency is prevented, and the operability in the lean air-fuel ratio operation is improved. Moreover, low load,
The exhaust timing is advanced in the low-speed rotation range N1, the exhaust gas in the combustion chamber is quickly released, the fuel exchange is smooth, the compression pressure is reduced, the operation is stabilized, and the operation with a lean air-fuel ratio is possible. To
【００２８】また、エンジンの低負荷、低速回転域Ｎ１
で排気制御バルブ２５を開くとともに、可動触媒３８を
排気管通路３４に進出させてチャンバ３３を排気管通路
３４と連通させ、このようにチャンバ３３と排気管通路
３４との連通に可動触媒３８を用いており、排気性能を
低下させることなく触媒活性を促進して排気浄化を向上
させている。Further, the engine has a low load and a low speed rotation range N1.
The exhaust gas control valve 25 is opened, and the movable catalyst 38 is advanced into the exhaust pipe passage 34 to communicate the chamber 33 with the exhaust pipe passage 34. Thus, the movable catalyst 38 is connected to the communication between the chamber 33 and the exhaust pipe passage 34. The catalyst is used to promote catalytic activity without lowering exhaust performance, thereby improving exhaust purification.
【００２９】なお、この実施例は、筒内噴射式２サイク
ルエンジンに適用しているが、燃料噴射式以外のエンジ
ンにも同様に適用することができる。Although this embodiment is applied to an in-cylinder injection type two-stroke engine, it can be similarly applied to engines other than the fuel injection type.
【００３０】[0030]
【発明の効果】前記のように、この請求項１記載の発明
は、エンジンの低負荷、低速回転域で排気制御バルブを
開くとともに、チャンバを排気管通路と連通させるか
ら、排気管の脈動による排気負圧をチャンバで減少さ
せ、体積効率低下を防止し、希薄空燃費での運転性を向
上させることができる。しかも、低負荷、低速回転域で
排気時期を進めて、圧縮圧力を軽減し、運転を安定させ
ることができる。As described above, according to the first aspect of the present invention, the exhaust control valve is opened in the low-load, low-speed rotation range of the engine and the chamber is communicated with the exhaust pipe passage. It is possible to reduce the exhaust negative pressure in the chamber, prevent a reduction in volumetric efficiency, and improve operability with lean air-fuel consumption. In addition, the exhaust timing can be advanced in the low-load, low-speed rotation range, the compression pressure can be reduced, and the operation can be stabilized.
【００３１】また、低負荷、低速回転域で可動触媒を排
気管通路に進出させるから、触媒活性を促進して排気浄
化を向上できる。一方、高負荷時、後退させることがで
きるので触煤の過熟を防ぎ耐久性を増大できる。Further, since the movable catalyst advances into the exhaust pipe passage in a low-load, low-speed rotation region, the catalytic activity can be promoted and the exhaust gas purification can be improved. On the other hand, when the load is high, it can be retracted, so that the soot can be prevented from being overripened and the durability can be increased.
【００３２】また、触媒を進退させるための部材である
取付フレームを有効に利用し、連通バルブを構成させる
ので、連通バルブを特別に設ける必要がなくなり装置の
複雑化を防ぐことができる。Further, since the connecting frame, which is a member for moving the catalyst forward and backward, is effectively used to constitute the communication valve, it is not necessary to provide a special communication valve, and the apparatus can be prevented from becoming complicated.
【図１】エンジンの排気装置の断面図である。FIG. 1 is a sectional view of an exhaust device of an engine.
【図２】エンジンの排気装置の要部の拡大図である。FIG. 2 is an enlarged view of a main part of an exhaust device of the engine.
【図３】低負荷及び低速回転域における可動触媒の作動
位置を示す図である。FIG. 3 is a diagram showing operating positions of a movable catalyst in a low load and low speed rotation range.
【図４】高負荷時及び高速回転域における可動触媒の作
動位置を示す図である。FIG. 4 is a diagram showing operating positions of a movable catalyst under a high load and in a high speed rotation range.
【図５】チャンバ開閉及び排気制御バルブ開閉とエンジ
ン回転数との関係を示す図である。FIG. 5 is a diagram showing the relationship between the opening / closing of a chamber and the opening / closing of an exhaust control valve and the engine speed;
３ シリンダボディ ２４ 排気通路 ２６ 排気管 ３１，３２ 分割触媒ハウジング ３３ チャンバ ３４ 排気管通路 ３８ 可動触媒 ４３ 制御装置 3 Cylinder body 24 Exhaust passage 26 Exhaust pipe 31, 32 Split catalyst housing 33 Chamber 34 Exhaust pipe passage 38 Movable catalyst 43 Control device
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平４−91414（ＪＰ，Ａ) 特開 平２−271023（ＪＰ，Ａ) 実開 平１−78232（ＪＰ，Ｕ) 実開 平２−105519（ＪＰ，Ｕ) 実開 昭61−62219（ＪＰ，Ｕ) (58)調査した分野(Int.Cl.7，ＤＢ名) F01N 3/08 - 3/38 F01N 9/00 - 11/00 F02B 25/20 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-91414 (JP, A) JP-A-2-271023 (JP, A) JP-A-1-78232 (JP, U) JP-A-2-27 105519 (JP, U) Actually open 1986-62219 (JP, U) (58) Fields investigated (Int. Cl. 7 , DB name) F01N 3/08-3/38 F01N 9/00-11/00 F02B 25/20
Claims (1)
じて排気時期を変化させる排気制御バルブを備えるとと
もに、前記排気通路に接続した排気管の排気管通路に設
けた触媒ハウジングの一部にチャンバを形成し、この触
媒ハウジングの内部に取付フレームを移動可能に取り付
け、この取付フレームに前記排気管通路の一部をなす枠
部を一対並設し、一方の枠部内に可動触媒を取付け、他
方の枠部内を空にし、前記取付けフレームは、前記可動
触媒が前記排気管通路に位置したとき前記空の枠部が前
記排気管通路より退却し、前記チャンバを前記排気管通
路に連通するとともに、前記空の枠部が前記排気管通路
に位置したとき前記可動触媒が前記排気管通路より退却
し、前記チャンバを遮断し排気が前記空の枠部内を通過
するよう動作して連通バルブを構成し、低負荷、低速回
転域で前記排気制御バルブを開くとともに前記可動触媒
を排気管通路に進出し、この排気管通路を前記チャンバ
に連通させたことを特徴とする２サイクルエンジンの排
気装置。An exhaust control valve for changing an exhaust timing in accordance with an engine speed is provided in an exhaust passage of an engine, and a part of a catalyst housing provided in an exhaust pipe passage of an exhaust pipe connected to the exhaust passage is provided. Is formed, a mounting frame is movably mounted inside the catalyst housing, a pair of frames forming a part of the exhaust pipe passage are arranged side by side on the mounting frame, and a movable catalyst is mounted in one of the frame portions, and When the movable frame is located in the exhaust pipe passage, the empty frame retreats from the exhaust pipe passage, and connects the chamber to the exhaust pipe passage. When the empty frame is located in the exhaust pipe passage, the movable catalyst retreats from the exhaust pipe passage, shuts off the chamber, and operates so that exhaust passes through the empty frame. A two-stroke engine, comprising a through valve, opening the exhaust control valve in a low-load, low-speed rotation range, moving the movable catalyst into an exhaust pipe passage, and communicating the exhaust pipe passage with the chamber. Exhaust system.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18012091A JP3194197B2 (en) | 1991-06-25 | 1991-06-25 | Exhaust system for two-cycle engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18012091A JP3194197B2 (en) | 1991-06-25 | 1991-06-25 | Exhaust system for two-cycle engine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH051527A JPH051527A (en) | 1993-01-08 |
| JP3194197B2 true JP3194197B2 (en) | 2001-07-30 |
Family
ID=16077771
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP18012091A Expired - Fee Related JP3194197B2 (en) | 1991-06-25 | 1991-06-25 | Exhaust system for two-cycle engine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3194197B2 (en) |
-
1991
- 1991-06-25 JP JP18012091A patent/JP3194197B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH051527A (en) | 1993-01-08 |
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