JPH10238334A - Four-cycle engine - Google Patents
Four-cycle engineInfo
- Publication number
- JPH10238334A JPH10238334A JP9037229A JP3722997A JPH10238334A JP H10238334 A JPH10238334 A JP H10238334A JP 9037229 A JP9037229 A JP 9037229A JP 3722997 A JP3722997 A JP 3722997A JP H10238334 A JPH10238334 A JP H10238334A
- Authority
- JP
- Japan
- Prior art keywords
- variable valve
- opening
- exhaust
- exhaust passage
- passage
- 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- Withdrawn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
-
- 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
- Y02T10/12—Improving ICE efficiencies
Landscapes
- Exhaust Silencers (AREA)
- Control Of Throttle Valves Provided In The Intake System Or In The Exhaust System (AREA)
- Exhaust Gas After Treatment (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】この発明は、希薄燃焼を行う
４サイクルエンジンに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a four-stroke engine that performs lean combustion.
【０００２】[0002]
【従来の技術】例えば、４サイクルエンジンには、イン
ジェクタから燃料を噴射して希薄燃焼を行うものがあ
り、このリーンバーンエンジンは燃費や排気ガスの改善
を目的としている。2. Description of the Related Art For example, some 4-cycle engines perform lean burn by injecting fuel from an injector, and this lean burn engine aims to improve fuel efficiency and exhaust gas.
【０００３】[0003]
【発明が解決しようとする課題】このようにインジェク
タから燃料を噴射して希薄燃焼を行うリーンバーンエン
ジンでは、ＮＯｘを低減するため、図１１に示すように
燃費、ＴＨＣ排出が最良点ではなく、若干悪化した領域
（リーン側）で運転している。そのＮＯｘ低減分（リー
ン限界拡大）のために、吸気効率を上げる必要があり吸
気系の大幅改造が必要になったり、全開性能を犠牲にす
る場合がある。As described above, in the lean burn engine in which the fuel is injected from the injector to perform the lean combustion, the fuel efficiency and the THC emission are not the best points as shown in FIG. The vehicle is operating in a slightly deteriorated area (lean side). In order to reduce the NOx (increase the lean limit), it is necessary to increase the intake efficiency, so that the intake system may need to be significantly modified or the full-open performance may be sacrificed.
【０００４】この発明は、かかる実情に鑑みてなされた
もので、吸気系の大幅改造や全開性能を犠牲にすること
なく、簡単な構造で排気エミッション低減を可能にする
４サイクルエンジンを提供することを目的としている。The present invention has been made in view of the above circumstances, and provides a four-stroke engine capable of reducing exhaust emissions with a simple structure without sacrificing a large modification of an intake system or full opening performance. It is an object.
【０００５】[0005]
【課題を解決するための手段】前記課題を解決し、かつ
目的を達成するために、請求項１記載の発明は、インジ
ェクタから燃料を噴射して希薄燃焼を行う４サイクルエ
ンジンにおいて、排気通路を開閉する可変バルブと、こ
の可変バルブの下流に配置され排気ガスの空燃比を検出
する空燃比検出手段と、吸気通路のスロットル弁の開度
を検出するスロットル開度検出手段と、エンジン回転数
を検出するエンジン回転数検出手段と、前記空燃比、ス
ロットル開度及びエンジン回転数に基づき前記可変バル
ブを開閉動作させ前記排気通路の通路断面積を増減させ
る制御手段とを設けたことを特徴としている。空燃比、
スロットル開度及びエンジン回転数に基づき可変バルブ
を開閉動作させて排気通路の通路断面積を増減させ、な
るベく最良燃費側・ＴＨＣ排出量低い側で、ＮＯｘ低減
を図ることができ、吸気系の大幅改造や全開性能を犠牲
にすることなく、簡単な構造で排気エミッション低減を
可能にする。In order to solve the above-mentioned problems and to achieve the object, according to the present invention, an exhaust passage is provided in a four-cycle engine in which fuel is injected from an injector to perform lean combustion. A variable valve that opens and closes, an air-fuel ratio detector that is disposed downstream of the variable valve and detects an air-fuel ratio of exhaust gas, a throttle opening detector that detects an opening of a throttle valve in an intake passage, and an engine speed. An engine speed detecting means for detecting, and a control means for opening and closing the variable valve based on the air-fuel ratio, the throttle opening and the engine speed to increase / decrease the cross-sectional area of the exhaust passage are provided. . Air-fuel ratio,
The variable valve is opened and closed based on the throttle opening and the engine speed to increase or decrease the cross-sectional area of the exhaust passage, so that the NOx can be reduced on the best fuel economy side and the lower THC emission side. The exhaust gas emission can be reduced with a simple structure without sacrificing the remodeling or full-opening performance.
【０００６】請求項２記載の発明の４サイクルエンジン
は、前記制御手段は、低負荷領域において前記可変バル
ブを閉じる方向に制御することを特徴としている。低負
荷領域においては、可変バルブを閉じる方向に作動する
ことで、筒内残留ガス（ＢＧＲ）割合を増加させ、燃費
に大きな影響を与えることなく、ＮＯｘ、ＴＨＣの低減
を図ることができる。A four-stroke engine according to a second aspect of the present invention is characterized in that the control means controls the variable valve to close in a low load range. In the low load region, by operating the variable valve in the closing direction, it is possible to increase the ratio of in-cylinder residual gas (BGR) and reduce NOx and THC without significantly affecting fuel efficiency.
【０００７】請求項３記載の発明は、通路断面積と通路
長が異なる２種類の排気通路を組み合わせた２重排気通
路構造にすると共に、前記一方の排気通路を開閉する可
変バルブを備え、前記スロットル弁の全開高速域で前記
可変バルブを開き、前記スロットル弁の全開低中速域で
前記可変バルブを閉じることを特徴としている。スロッ
トル弁の全開高速域では可変バルブを開くことで高出力
が得られる。また、スロットル弁の全開低中速域では可
変バルブを閉じ、低中速トルク向上及び高圧縮比化を図
るとともに、低負荷域の排気エミッション低減が可能で
ある。According to a third aspect of the present invention, there is provided a double exhaust passage structure in which two types of exhaust passages having different passage cross-sectional areas and different passage lengths are combined, and a variable valve for opening and closing the one exhaust passage is provided. The variable valve is opened in a high speed range where the throttle valve is fully opened, and the variable valve is closed in a low / medium speed range where the throttle valve is fully opened. In the high speed region where the throttle valve is fully opened, a high output can be obtained by opening the variable valve. Further, the variable valve is closed in the low-medium-speed region where the throttle valve is fully opened to improve the low-medium-speed torque and increase the compression ratio, and to reduce the exhaust emission in the low-load region.
【０００８】[0008]
【発明の実施の形態】以下、この発明の４サイクルエン
ジンの実施の形態を図面に基づいて説明する。図１は４
サイクルエンジンの構成を示す図、図２は排気通路に配
置した可変バルブを示す図、図３は可変バルブの制御ブ
ロック図、図４は可変バルブの開度とＴＨＣ・ＮＯｘ及
び燃費との関係を示す図である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a four-stroke engine according to the present invention will be described with reference to the drawings. Figure 1 is 4
FIG. 2 is a diagram showing a configuration of a cycle engine, FIG. 2 is a diagram showing a variable valve arranged in an exhaust passage, FIG. 3 is a control block diagram of the variable valve, and FIG. 4 is a diagram showing the relationship between the opening degree of the variable valve and THC / NOx and fuel efficiency. FIG.
【０００９】４サイクルエンジン１のクランクケース２
には、シリンダブロック３が載置され、シリンダブロッ
ク３にはシリンダヘッド４を装着して内部に燃焼室５が
形成されている。シリンダヘッド４には、点火プラグ６
が燃焼室５に臨むように設けられている。シリンダブロ
ック３に形成される筒内３ａには、ピストン７が往復動
可能に設けられている。このピストン７はコンロッド８
を介してクランク軸９に連結され、ピストン７の往復動
によりクランク軸９が回転する。クランクケース２に
は、クランク軸９に対応してエンジン回転数検出手段１
０が配置され、エンジン回転数検出手段１０は、例えば
クランク角センサで構成される。エンジン回転数検出手
段１０はエンジン回転数を検出し、このエンジン回転数
情報を制御手段を構成するＥＣＵ１１に送る。シリンダ
ヘッド４にはヘッドカバー１２が取り付けられている。Crankcase 2 of four-cycle engine 1
, A cylinder block 3 is mounted, and a cylinder head 4 is mounted on the cylinder block 3 to form a combustion chamber 5 therein. The cylinder head 4 has a spark plug 6
Are provided so as to face the combustion chamber 5. A piston 7 is provided in the cylinder 3a formed in the cylinder block 3 so as to be able to reciprocate. This piston 7 is a connecting rod 8
The crankshaft 9 is connected to the crankshaft 9 through the reciprocating motion of the piston 7. The crankcase 2 has an engine speed detecting means 1 corresponding to the crankshaft 9.
0 is arranged, and the engine speed detecting means 10 is constituted by, for example, a crank angle sensor. The engine speed detecting means 10 detects the engine speed and sends the engine speed information to the ECU 11 which constitutes the control means. A head cover 12 is attached to the cylinder head 4.
【００１０】シリンダヘッド４には、３個の吸気通路１
３と２個の排気通路１４が形成され、それぞれ燃焼室５
に開口している。吸気通路１３は上流側で集合して吸気
管３０に接続され、その開口部１３ａは吸気弁１５で開
閉される。排気通路１４は下流で集合して排気管４０に
接続され、その開口部１４ａは排気弁１６で開閉され
る。この吸気弁１５及び排気弁１６は動弁機構１７を構
成するカム軸１８，１９に設けたカム２０，２１により
作動する。カム軸１８，１９にはカムスプロケット２
２，２３が設けられ、一方クランク軸９には駆動スプロ
ケット２４が設けられ、カムスプロケット２２，２３と
駆動スプロケット２４とにカムチェーン２５が掛け渡さ
れている。カム軸１８，１９はカムチェーン２５を介し
てクランク軸９と連動して回転し、所定のタイミングで
それぞれのカム２０，２１が吸気弁１５及び排気弁１６
を開閉する。The cylinder head 4 has three intake passages 1.
3 and two exhaust passages 14 are formed, each of which has a combustion chamber 5.
It is open to. The intake passage 13 is gathered on the upstream side and connected to the intake pipe 30, and an opening 13 a thereof is opened and closed by the intake valve 15. The exhaust passage 14 gathers downstream and is connected to an exhaust pipe 40, and its opening 14 a is opened and closed by an exhaust valve 16. The intake valve 15 and the exhaust valve 16 are operated by cams 20 and 21 provided on cam shafts 18 and 19 constituting a valve mechanism 17. The cam shafts 18 and 19 have cam sprockets 2
2 and 23 are provided, while a drive sprocket 24 is provided on the crankshaft 9, and a cam chain 25 is stretched over the cam sprockets 22 and 23 and the drive sprocket 24. The camshafts 18 and 19 rotate in conjunction with the crankshaft 9 via a cam chain 25, and the cams 20 and 21 respectively move the intake valves 15 and the exhaust valves 16 at predetermined timing.
Open and close.
【００１１】吸気管３０にはスロットル弁３１が設けら
れ、スロットル弁３１の開閉により吸入空気量を制御す
る。スロットル弁３１の開度をスロットル開度検出手段
３２により検出し、スロットル開度情報をＥＣＵ１１に
送る。スロットル開度検出手段３２は、例えばポテンシ
ョメータで構成される。スロットル弁３１の下流側に
は、インジェクタ３３が設けられ、このインジェクタ３
３から燃料を噴射して希薄燃焼を行う。A throttle valve 31 is provided in the intake pipe 30, and the amount of intake air is controlled by opening and closing the throttle valve 31. The opening of the throttle valve 31 is detected by the throttle opening detecting means 32, and the throttle opening information is sent to the ECU 11. The throttle opening detecting means 32 is constituted by, for example, a potentiometer. Downstream of the throttle valve 31, an injector 33 is provided.
Fuel is injected from 3 to perform lean combustion.
【００１２】排気管４０には排気通路を開閉する可変バ
ルブ４１が配置されている。可変バルブ４１の上側に
は、図２に示すように切欠き４１ａが設けられ、可変バ
ルブ４１を全閉にしたときに排気ガスが切欠き４１ａか
らリークできるようになっている。可変バルブ４１の下
流には、空燃比検出手段４２が設けられ、排気ガスの空
燃比を検出し、空燃比情報をＥＣＵ１１に送る。空燃比
検出手段４２は、例えばＯ2センサで構成される。The exhaust pipe 40 is provided with a variable valve 41 for opening and closing the exhaust passage. As shown in FIG. 2, a notch 41a is provided above the variable valve 41, and when the variable valve 41 is fully closed, exhaust gas can leak from the notch 41a. An air-fuel ratio detecting unit 42 is provided downstream of the variable valve 41, detects the air-fuel ratio of the exhaust gas, and sends the air-fuel ratio information to the ECU 11. The air-fuel ratio detecting means 42 is composed of, for example, an O 2 sensor.
【００１３】ＥＣＵ１１は、図３に示すように、可変バ
ルブ開度設定手段１１０、記憶手段１１１及び可変バル
ブ駆動手段１１２が備えられている。記憶手段１１１に
は、予め空燃比、スロットル開度及びエンジン回転数に
基づく可変バルブ開度のマップが記憶されている。可変
バルブ開度設定手段１１０は、空燃比検出手段４２から
の空燃比、スロットル開度検出手段３２からのスロット
ル開度及びエンジン回転数検出手段１０からのエンジン
回転数に基づき記憶手段１１１に記憶されたマップから
所定の可変バルブ開度を設定する。この可変バルブ開度
に基づき可変バルブ駆動手段１１２を介して可変バルブ
４１を開閉し、この可変バルブ４１の開閉動作により排
気通路の通路断面積を増減させる。As shown in FIG. 3, the ECU 11 is provided with a variable valve opening setting means 110, a storage means 111, and a variable valve driving means 112. The storage means 111 stores a map of the variable valve opening based on the air-fuel ratio, the throttle opening and the engine speed in advance. The variable valve opening setting means 110 is stored in the storage means 111 based on the air-fuel ratio from the air-fuel ratio detecting means 42, the throttle opening from the throttle opening detecting means 32, and the engine speed from the engine speed detecting means 10. The predetermined variable valve opening is set from the map. The variable valve 41 is opened and closed via the variable valve driving means 112 based on the variable valve opening, and the opening and closing operation of the variable valve 41 increases or decreases the cross-sectional area of the exhaust passage.
【００１４】このように空燃比、スロットル開度及びエ
ンジン回転数に基づき可変バルブ４１を開閉動作させて
排気通路の通路断面積を増減させることで、なるベく最
良燃費側・ＴＨＣ排出量低い側で、ＮＯｘ低減を図るこ
とができ、吸気系の大幅改造や全開性能を犠牲にするこ
となく、簡単な構造で排気エミッション低減を可能にす
ることができる。As described above, by opening and closing the variable valve 41 based on the air-fuel ratio, the throttle opening, and the engine speed to increase or decrease the cross-sectional area of the exhaust passage, the best fuel consumption side and the lower THC emission side are obtained. Thus, NOx can be reduced, and exhaust emission can be reduced with a simple structure without significantly modifying the intake system or sacrificing the full opening performance.
【００１５】即ち、低負荷領域においては、可変バルブ
４１を閉じる方向に制御し、筒内残留ガス（ＢＧＲ）割
合を増加させ、図４に示すように燃費に大きな影響を与
えないで、ＮＯｘ、ＴＨＣの低減を図ることができる。That is, in the low load range, the variable valve 41 is controlled to be closed so as to increase the ratio of the residual gas (BGR) in the cylinder. As shown in FIG. THC can be reduced.
【００１６】次に、図５乃至図１１に基づいて４サイク
ルエンジンの他の実施の形態について説明する。図５は
４サイクルエンジンの構成を示す図、図６は排気通路及
び可変バルブの構造を示す図、図７は排気通路及び可変
バルブの他の実施の形態の構造を示す図である。Next, another embodiment of the four-stroke engine will be described with reference to FIGS. FIG. 5 is a diagram showing the configuration of a four-cycle engine, FIG. 6 is a diagram showing the structure of an exhaust passage and a variable valve, and FIG. 7 is a diagram showing the structure of another embodiment of an exhaust passage and a variable valve.
【００１７】この実施の形態では、図１乃至図４に示す
実施の形態と同様に構成されるものは同じ符号を付して
説明を省略する。この実施の形態では、大通路断面積の
排気通路２００が短く、小通路断面積の排気通路２０１
が長くしてマフラー２０２を連結し、通路断面積と通路
長が異なる２種類の排気通路２００，２０１を組み合わ
せた２重排気通路構造になっているが、大通路断面積の
排気通路２００を長く、小通路断面積の排気通路２０１
を短くしてもよい。In this embodiment, components similar to those in the embodiment shown in FIGS. 1 to 4 are denoted by the same reference numerals, and description thereof is omitted. In this embodiment, the exhaust passage 200 having the large passage cross section is short, and the exhaust passage 201 having the small passage cross section is provided.
And the muffler 202 is connected to form a double exhaust passage structure combining two types of exhaust passages 200 and 201 having different passage sectional areas and passage lengths. However, the exhaust passage 200 having a large passage sectional area is made longer. Exhaust passage 201 with small passage cross section
May be shortened.
【００１８】２重排気通路構造は、図６に示す実施の形
態では、大径の排気管３００の内部に小径の排気管３０
１を配置して大通路断面積の排気通路２００と小通路断
面積の排気通路２０１とが構成され、あるいは図７に示
すように大径の排気管３１０の内部に仕切り壁３１１を
配置して大通路断面積の排気通路２００と小通路断面積
の排気通路２０１とが構成される。In the embodiment shown in FIG. 6, the double exhaust passage structure has a small-diameter exhaust pipe 30 inside a large-diameter exhaust pipe 300.
1 to form an exhaust passage 200 having a large passage cross-sectional area and an exhaust passage 201 having a small passage cross-sectional area, or a partition wall 311 disposed inside a large-diameter exhaust pipe 310 as shown in FIG. An exhaust passage 200 having a large passage sectional area and an exhaust passage 201 having a small passage sectional area are formed.
【００１９】大通路断面積の排気通路２００を開閉する
可変バルブ４１が備えられ、この可変バルブ４１の配置
位置は、気筒とマフラー２０２との間に４サイクルエン
ジン１に応じて適宜配置される。この可変バルブ４１
は、ＥＣＵ１１により開閉制御され、スロットル弁３１
の全開高速域で可変バルブ４１を開き、スロットル弁３
１の全開低中速域で可変バルブ４１を閉じる。なお、可
変バルブ４１は、スロットル弁３１と機械的に連結し、
スロットル弁３１と連動して開閉作動するようにしても
よい。A variable valve 41 for opening and closing the exhaust passage 200 having a large cross-sectional area is provided. The position of the variable valve 41 is appropriately set between the cylinder and the muffler 202 according to the four-cycle engine 1. This variable valve 41
The opening and closing of the throttle valve 31 is controlled by the ECU 11.
Open the variable valve 41 in the fully open high speed range of the throttle valve 3
The variable valve 41 is closed in the fully open low / medium speed range of 1. The variable valve 41 is mechanically connected to the throttle valve 31,
The opening and closing operation may be performed in conjunction with the throttle valve 31.
【００２０】このように、スロットル弁３１の全開高速
域では可変バルブ４１を開くことで高出力が得られる。
また、スロットル弁３１の全開低中速域では可変バルブ
４１を閉じ、低中速トルク向上及び高圧縮比化を図ると
ともに、低負荷域の排気エミッション低減が可能であ
る。As described above, in the high speed range where the throttle valve 31 is fully opened, a high output can be obtained by opening the variable valve 41.
In addition, in the low-medium-speed region where the throttle valve 31 is fully opened, the variable valve 41 is closed to improve the low-medium-speed torque and increase the compression ratio, and to reduce the exhaust emission in the low-load region.
【００２１】即ち、図８はエンジン回転数とトルクとの
関係を示す図である。図８（ａ）は従来の排気通路の出
口絞り率を変更する例であり、図８（ｂ）は従来の同一
径の排気管の出口絞り率を変更する例であり、図８
（ｃ）はこの発明の実施の形態の通路断面積と通路長が
異なる２種類の排気通路を組み合わせた２重排気通路構
造の通路断面積を変更する例である。図８（ａ）及び図
８（ｂ）では、低中速域のトルクが低いが、図８（ｃ）
は低中速域から高速域まで高トルクを得られる。FIG. 8 is a diagram showing the relationship between the engine speed and the torque. FIG. 8A shows an example in which the outlet throttle ratio of the conventional exhaust passage is changed, and FIG. 8B shows an example in which the outlet throttle ratio of the conventional exhaust pipe having the same diameter is changed.
(C) is an example in which the passage cross-sectional area of a double exhaust passage structure combining two types of exhaust passages having different passage cross-sectional areas and passage lengths according to the embodiment of the present invention is changed. 8 (a) and 8 (b), the torque in the low to middle speed range is low, but FIG. 8 (c)
Can obtain high torque from low to medium speed range to high speed range.
【００２２】また、図９はエンジン回転数と残留ガス濃
度及び筒内ガス温度との関係を示す図である。排気バル
ブ全開時の残留ガス濃度特性曲線ａ１及び筒内ガス温度
ａ２は、従来の排気通路の出口絞りの例であり、または
同一径の排気管の出口絞りの例である。また、排気バル
ブ全開時の残留ガス濃度特性曲線ｂ１及び筒内ガス温度
ｂ２は、この発明の実施の形態の通路断面積と通路長が
異なる２種類の排気通路を組み合わせた２重排気通路構
造の通路断面積を変更する例で、可変バルブが全閉状態
でブランチ効果がないものであり、残留ガス濃度特性曲
線ｃ１及び筒内ガス温度ｃ２は、可変バルブが全閉状態
でブランチ効果があるものである。FIG. 9 is a graph showing the relationship among the engine speed, the residual gas concentration and the in-cylinder gas temperature. The residual gas concentration characteristic curve a1 and the in-cylinder gas temperature a2 when the exhaust valve is fully opened are examples of a conventional exhaust passage outlet throttle or an example of an exhaust pipe outlet throttle of the same diameter. Further, the residual gas concentration characteristic curve b1 and the in-cylinder gas temperature b2 when the exhaust valve is fully opened are determined by the double exhaust passage structure of the embodiment of the present invention in which two types of exhaust passages having different passage cross-sectional areas and different passage lengths are combined. In the example in which the cross-sectional area of the passage is changed, the variable valve is in the fully closed state and there is no branch effect. The residual gas concentration characteristic curve c1 and the in-cylinder gas temperature c2 are those in which the variable valve has the branch effect when fully closed. It is.
【００２３】この発明の実施の形態では、残留ガス濃度
の低減により筒内ガス温度が低下し、従来のようなノッ
キングの発生を防止することができ、従来より高圧縮比
化を図ることができる。In the embodiment of the present invention, the in-cylinder gas temperature is reduced due to the reduction of the residual gas concentration, so that the occurrence of knocking as in the prior art can be prevented, and a higher compression ratio can be achieved than in the prior art. .
【００２４】また、図１０はエンジン回転数と低負荷時
の残留ガス濃度との関係を示す図である。部分負荷時の
残留ガス濃度特性曲線ａ３は、従来の排気通路の出口絞
りの例であり、または同一径の排気管の出口絞りの例で
ある。部分負荷時の残留ガス濃度特性曲線ｂ３は、この
発明の実施の形態の通路断面積と通路長が異なる２種類
の排気通路を組み合わせた２重排気通路構造の通路断面
積を変更する例で、可変バルブが全閉状態でブランチ効
果がないものであり、残留ガス濃度特性曲線ｃ３は、可
変バルブが全閉状態でブランチ効果があるものである。
残留ガス濃度を制御することで、低負荷域の排気エミッ
ション低減が可能である。FIG. 10 is a graph showing the relationship between the engine speed and the residual gas concentration at low load. The residual gas concentration characteristic curve a3 at the time of partial load is an example of a conventional exhaust passage outlet throttle or an example of an exhaust pipe outlet throttle of the same diameter. The residual gas concentration characteristic curve b3 at the time of partial load is an example in which the passage sectional area of a double exhaust passage structure in which two kinds of exhaust passages having different passage sectional areas and passage lengths are combined according to the embodiment of the present invention is changed. There is no branch effect when the variable valve is fully closed, and the residual gas concentration characteristic curve c3 shows a branch effect when the variable valve is fully closed.
By controlling the residual gas concentration, it is possible to reduce exhaust emissions in a low load region.
【００２５】[0025]
【発明の効果】前記したように、請求項１記載の発明で
は、空燃比、スロットル開度及びエンジン回転数に基づ
き可変バルブを開閉動作させて排気通路の通路断面積を
増減させ、なるベく最良燃費側・ＴＨＣ排出量低い側
で、ＮＯｘ低減を図ることができ、吸気系の大幅改造や
全開性能を犠牲にすることなく、簡単な構造で排気エミ
ッション低減を可能にする。As described above, according to the first aspect of the present invention, the variable valve is opened and closed based on the air-fuel ratio, the throttle opening and the engine speed to increase or decrease the cross-sectional area of the exhaust passage. NOx can be reduced on the best fuel consumption side and on the side with low THC emission, and exhaust emission can be reduced with a simple structure without drastically modifying the intake system or sacrificing full opening performance.
【００２６】請求項２記載の発明では、低負荷領域にお
いては、可変バルブを閉じる方向に作動することで、筒
内残留ガス（ＢＧＲ）割合を増加させ、燃費に大きな影
響を与えることなく、ＮＯｘ、ＴＨＣの低減を図ること
ができる。According to the second aspect of the present invention, in the low load range, the ratio of the residual gas (BGR) in the cylinder is increased by operating the variable valve in the closing direction, and the NOx is not significantly affected without increasing the fuel efficiency. , THC can be reduced.
【００２７】請求項３記載の発明では、通路断面積と通
路長が異なる２種類の排気通路を組み合わせた２重排気
通路構造にすると共に、一方の排気通路を開閉する可変
バルブを備え、スロットル弁の全開高速域では可変バル
ブを開くことで高出力が得られ、またスロットル弁の全
開低中速域では可変バルブを閉じ、低中速トルク向上及
び高圧縮比化を図るとともに、低負荷域の排気エミッシ
ョン低減が可能である。According to a third aspect of the present invention, a double exhaust passage structure is provided in which two types of exhaust passages having different passage cross-sectional areas and different passage lengths are combined, and a variable valve for opening and closing one exhaust passage is provided. In the fully open high speed range, high output can be obtained by opening the variable valve, and in the fully open low to medium speed range of the throttle valve, the variable valve is closed to improve the low to medium speed torque and increase the compression ratio, Exhaust emissions can be reduced.
【図１】４サイクルエンジンの構成を示す図である。FIG. 1 is a diagram showing a configuration of a four-cycle engine.
【図２】排気通路に配置した可変バルブを示す図であ
る。FIG. 2 is a view showing a variable valve arranged in an exhaust passage.
【図３】可変バルブの制御ブロック図である。FIG. 3 is a control block diagram of a variable valve.
【図４】可変バルブの開度とＴＨＣ・ＮＯｘ及び燃費と
の関係を示す図である。FIG. 4 is a diagram showing the relationship between the opening degree of a variable valve, THC / NOx, and fuel consumption.
【図５】４サイクルエンジンの構成を示す図である。FIG. 5 is a diagram showing a configuration of a four-cycle engine.
【図６】排気通路及び可変バルブの構造を示す図であ
る。FIG. 6 is a view showing a structure of an exhaust passage and a variable valve.
【図７】排気通路及び可変バルブの他の実施の形態の構
造を示す図である。FIG. 7 is a view showing a structure of another embodiment of an exhaust passage and a variable valve.
【図８】エンジン回転数とトルクとの関係を示す図であ
る。FIG. 8 is a diagram showing a relationship between engine speed and torque.
【図９】エンジン回転数と残留ガス濃度及び筒内ガス温
度との関係を示す図である。FIG. 9 is a diagram showing a relationship among an engine speed, a residual gas concentration, and a gas temperature in a cylinder.
【図１０】エンジン回転数と低負荷時の残留ガス濃度と
の関係を示す図である。FIG. 10 is a diagram showing a relationship between an engine speed and a residual gas concentration at a low load.
【図１１】リーン化による燃費と排気ガスの関係を示す
図である。FIG. 11 is a diagram showing a relationship between fuel efficiency and exhaust gas due to lean operation.
１ ４サイクルエンジン １０ エンジン回転数検出手段 １１ ＥＣＵ ３１ スロットル弁 ３２ スロットル開度検出手段 ３３ インジェクタ ４１ 可変バルブ ４２ 空燃比検出手段 Reference Signs List 1 4 cycle engine 10 Engine speed detecting means 11 ECU 31 Throttle valve 32 Throttle opening detecting means 33 Injector 41 Variable valve 42 Air-fuel ratio detecting means
フロントページの続き (51)Int.Cl.6 識別記号 ＦＩ Ｆ０２Ｄ 45/00 ３６２ Ｆ０２Ｄ 45/00 ３６２Ｈ ３６４ ３６４Ｇ ３６８ ３６８Ｇ Continued on the front page (51) Int.Cl. 6 Identification code FI F02D 45/00 362 F02D 45/00 362H 364 364G 368 368G
Claims (3)
を行う４サイクルエンジンにおいて、排気通路を開閉す
る可変バルブと、この可変バルブの下流に配置され排気
ガスの空燃比を検出する空燃比検出手段と、吸気通路の
スロットル弁の開度を検出するスロットル開度検出手段
と、エンジン回転数を検出するエンジン回転数検出手段
と、前記空燃比、スロットル開度及びエンジン回転数に
基づき前記可変バルブを開閉動作させ前記排気通路の通
路断面積を増減させる制御手段とを設けたことを特徴と
する４サイクルエンジン。In a four-stroke engine in which fuel is injected from an injector to perform lean combustion, a variable valve that opens and closes an exhaust passage and air-fuel ratio detection means that is disposed downstream of the variable valve and detects an air-fuel ratio of exhaust gas. A throttle opening detecting means for detecting an opening of a throttle valve in an intake passage; an engine speed detecting means for detecting an engine speed; and the variable valve based on the air-fuel ratio, the throttle opening and the engine speed. A four-stroke engine provided with control means for opening and closing to increase or decrease the cross-sectional area of the exhaust passage.
可変バルブを閉じる方向に制御することを特徴とする請
求項１記載の４サイクルエンジン。2. The four-stroke engine according to claim 1, wherein said control means controls the variable valve to close in a low load range.
通路を組み合わせた２重排気通路構造にすると共に、前
記一方の排気通路を開閉する可変バルブを備え、前記ス
ロットル弁の全開高速域で前記可変バルブを開き、前記
スロットル弁の全開低中速域で前記可変バルブを閉じる
ことを特徴とする請求項１または請求項２記載の４サイ
クルエンジン。3. A double exhaust passage structure combining two types of exhaust passages having different passage cross-sectional areas and passage lengths, a variable valve for opening and closing said one exhaust passage, and a fully open high-speed region of said throttle valve. 3. The four-stroke engine according to claim 1, wherein the variable valve is opened at a low speed and a medium speed range where the throttle valve is fully opened.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9037229A JPH10238334A (en) | 1997-02-21 | 1997-02-21 | Four-cycle engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9037229A JPH10238334A (en) | 1997-02-21 | 1997-02-21 | Four-cycle engine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH10238334A true JPH10238334A (en) | 1998-09-08 |
Family
ID=12491782
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9037229A Withdrawn JPH10238334A (en) | 1997-02-21 | 1997-02-21 | Four-cycle engine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH10238334A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6336321B1 (en) | 1999-01-22 | 2002-01-08 | Honda Giken Kogyo Kabushiki Kaisha | Engine exhaust assembly for a motorcycle |
| EP1215372A3 (en) * | 2000-12-14 | 2003-12-17 | J. Eberspächer GmbH & Co. KG | Exhaust system of a motor vehicle |
| US7325651B2 (en) * | 2004-02-27 | 2008-02-05 | Kawasaki Jukogyo Kabushiki Kaisha | Motorcycle exhaust system |
| JP2009085098A (en) * | 2007-09-28 | 2009-04-23 | Honda Motor Co Ltd | Exhaust control device in four-cycle engine |
-
1997
- 1997-02-21 JP JP9037229A patent/JPH10238334A/en not_active Withdrawn
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6336321B1 (en) | 1999-01-22 | 2002-01-08 | Honda Giken Kogyo Kabushiki Kaisha | Engine exhaust assembly for a motorcycle |
| US6546722B2 (en) | 1999-01-22 | 2003-04-15 | Honda Giken Kogyo Kabushiki Kaisha | Engine exhaust assembly for a motorcycle |
| DE10002593B4 (en) * | 1999-01-22 | 2013-06-27 | Honda Giken Kogyo K.K. | Engine exhaust device and motorcycle exhaust device |
| EP1215372A3 (en) * | 2000-12-14 | 2003-12-17 | J. Eberspächer GmbH & Co. KG | Exhaust system of a motor vehicle |
| US7325651B2 (en) * | 2004-02-27 | 2008-02-05 | Kawasaki Jukogyo Kabushiki Kaisha | Motorcycle exhaust system |
| JP2009085098A (en) * | 2007-09-28 | 2009-04-23 | Honda Motor Co Ltd | Exhaust control device in four-cycle engine |
| JP4625490B2 (en) * | 2007-09-28 | 2011-02-02 | 本田技研工業株式会社 | Exhaust control device for 4-cycle engine |
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