JP4654973B2 - Exhaust device for internal combustion engine - Google Patents

Exhaust device for internal combustion engine Download PDF

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JP4654973B2
JP4654973B2 JP2006142190A JP2006142190A JP4654973B2 JP 4654973 B2 JP4654973 B2 JP 4654973B2 JP 2006142190 A JP2006142190 A JP 2006142190A JP 2006142190 A JP2006142190 A JP 2006142190A JP 4654973 B2 JP4654973 B2 JP 4654973B2
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exhaust
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JP2007315173A (en
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健 佐藤
翔 高橋
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Nissan Motor Co Ltd
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    • 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
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    • Y02T10/12—Improving ICE efficiencies

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Description

本発明は、内燃機関の排気装置に関する。   The present invention relates to an exhaust device for an internal combustion engine.

特許文献１には、排気タービン式過給機を備えた内燃機関において、排気ガスの一部を吸気系に還流させるＥＧＲ通路にＥＧＲクーラが配置されたものが開示されている。   Patent Document 1 discloses an internal combustion engine equipped with an exhaust turbine supercharger in which an EGR cooler is arranged in an EGR passage that recirculates a part of exhaust gas to an intake system.

尚、排気タービン式過給機は、同一軸に取り付けたタービンロータ及びコンプレッサロータを有し、排気通路内の排気ガスによって駆動するタービンロータで吸気通路内のコンプレッサロータを駆動し、空気を圧縮し高密度の空気をエンジンへ供給するものである。
特開平１０−３２５３６８号公報 The exhaust turbine supercharger has a turbine rotor and a compressor rotor attached to the same shaft, and the compressor rotor in the intake passage is driven by the turbine rotor driven by the exhaust gas in the exhaust passage to compress the air. It supplies high-density air to the engine.
JP-A-10-325368

しかしながら、この特許文献１においては、エンジン始動直後で排気浄化用の触媒を早期に活性化させる際には、ＥＧＲクーラを介さずに排気ガスを触媒に導入することが可能であるが、排気タービン式過給機（タービンロータ）を排気ガスがバイパスする構造とはなっていないため、排気タービン式過給機を通過することによって排気ガスの温度が相対的に低下し、十分な触媒の早期活性化を図ることが難しいという問題がある。つまり、内燃機関の運転性能を早期に最大限引き出すことが困難となっている。   However, in this Patent Document 1, when the exhaust purification catalyst is activated immediately after engine startup, exhaust gas can be introduced into the catalyst without using an EGR cooler. Since the exhaust gas bypass structure does not bypass the turbocharger (turbine rotor), the exhaust gas temperature relatively decreases by passing through the exhaust turbine supercharger, and sufficient early activation of the catalyst There is a problem that it is difficult to plan. That is, it is difficult to maximize the operating performance of the internal combustion engine at an early stage.

また、触媒の活性時間が十分に短縮されず、それに伴い、エンジンの冷却水温の上昇が遅れ、結果的に排気ガスを吸気系に還流させることができる時期が遅れ、燃費性能の向上が十分ではないという問題がある。   In addition, the activation time of the catalyst is not shortened sufficiently, and as a result, the rise in the engine coolant temperature is delayed, resulting in a delay in the time when the exhaust gas can be recirculated to the intake system, and the fuel consumption performance is not sufficiently improved. There is no problem.

そこで、本発明は、排気タービン式過給機のタービンロータが配置された排気通路と、タービンロータをバイパスするよう排気通路に接続されたバイパス通路と、バイパス通路内に配置されウエストゲート弁と、排気通路に対するバイパス通路の接続位置よりも排気上流側で排気通路に対して接続され、排気通路内の排気ガスを吸気系に導入するＥＧＲ通路と、ＥＧＲ通路に配置されたＥＧＲクーラと、ＥＧＲクーラよりもＥＧＲ通路における排気下流側に配置され吸気系に導入される排気ガス導入量を制御するＥＧＲ弁と、を備えた内燃機関の排気装置において、ＥＧＲ通路と排気通路との接続位置となるＥＧＲ通路接続部に３方向の流れを制御可能な第１方向制御手段が配置され、バイパス通路と排気通路との接続位置のうち、タービンロータの排気上流側に位置するバイパス通路上流側接続部に３方向の流れを制御可能な第２方向制御手段が配置され、ＥＧＲ通路におけるＥＧＲクーラとＥＧＲ弁との間の区間と、バイパス通路におけるウエストゲート弁よりも排気上流側の区間との間を連通させる連絡通路が設けられていることを特徴としている。   Accordingly, the present invention provides an exhaust passage in which a turbine rotor of an exhaust turbine supercharger is disposed, a bypass passage connected to the exhaust passage so as to bypass the turbine rotor, a wastegate valve disposed in the bypass passage, An EGR passage that is connected to the exhaust passage upstream of the connection position of the bypass passage to the exhaust passage and introduces exhaust gas in the exhaust passage into the intake system; an EGR cooler disposed in the EGR passage; and an EGR cooler And an EGR valve that controls an exhaust gas introduction amount that is disposed on the exhaust gas downstream side of the EGR passage and that is introduced into the intake system. EGR serving as a connection position between the EGR passage and the exhaust passage A first direction control means capable of controlling the flow in three directions is disposed in the passage connection portion, and the turbine is located among the connection positions of the bypass passage and the exhaust passage The second direction control means capable of controlling the flow in three directions is arranged at the upstream side of the bypass passage located on the upstream side of the exhaust of the motor, the section between the EGR cooler and the EGR valve in the EGR passage, and the bypass passage A communication passage that communicates with a section on the exhaust upstream side of the wastegate valve is provided.

本発明によれば、運転状態に応じて、第１及び第２方向制御手段、ＥＧＲ弁及びウエストゲート弁を制御することで、排気ガスの流れを最適化することができ、内燃機関の運転性能を早期に最大限引き出すことが可能となる。   According to the present invention, the flow of exhaust gas can be optimized by controlling the first and second direction control means, the EGR valve, and the wastegate valve according to the operating state, and the operating performance of the internal combustion engine. Can be maximized at an early stage.

以下、本発明の一実施形態を図面に基づいて詳細に説明する。図１は、本発明に係る内燃機関の排気装置の概略構成模式的に示した説明図である。   Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory view schematically showing a schematic configuration of an exhaust device for an internal combustion engine according to the present invention.

内燃機関１の排気通路２には、排気タービン式過給機のタービンロータ３が配置されていると共に、このタービンロータ３をバイパスするバイパス通路４が接続されている。   A turbine rotor 3 of an exhaust turbine supercharger is disposed in an exhaust passage 2 of the internal combustion engine 1, and a bypass passage 4 that bypasses the turbine rotor 3 is connected.

排気タービン式過給機は、同一軸に取り付けたタービンロータ３及びコンプレッサロータ（図示せず）を有するものであり、排気通路２内の排気ガスによって駆動するタービンロータ３で吸気通路内のコンプレッサロータを駆動し、空気を圧縮し高密度の空気を内燃機関１へ供給するものである。   The exhaust turbine supercharger has a turbine rotor 3 and a compressor rotor (not shown) attached to the same shaft, and is a turbine rotor 3 driven by exhaust gas in the exhaust passage 2 and a compressor rotor in the intake passage. Is driven, air is compressed, and high-density air is supplied to the internal combustion engine 1.

バイパス通路４には、運転状態に応じて決まる過給圧の設定上限値を超えないように過給圧制御を実施可能なウエストゲート弁５が配置されている。   In the bypass passage 4, a wastegate valve 5 capable of supercharging pressure control is disposed so as not to exceed a set upper limit value of the supercharging pressure determined according to the operation state.

そして、排気通路２には、排気通路２とバイパス通路４との接続位置よりも排気上流側で、排気通路２内の排気ガスを吸気系に導入するＥＧＲ通路６が接続されている。このＥＧＲ通路６には、ＥＧＲクーラ７が配置されていると共に、ＥＧＲクーラ７よりもＥＧＲ通路６における排気下流側に吸気系に導入される排気ガス導入量を制御するＥＧＲ弁８が配置されている。   The exhaust passage 2 is connected to an EGR passage 6 that introduces exhaust gas in the exhaust passage 2 into the intake system upstream of the connection position between the exhaust passage 2 and the bypass passage 4. An EGR cooler 7 is disposed in the EGR passage 6, and an EGR valve 8 that controls the amount of exhaust gas introduced into the intake system downstream of the EGR cooler 7 in the EGR passage 6 is disposed. Yes.

尚、バイパス通路４と排気通路２との接続位置のうちタービンロータ３の排気下流側に位置するバイパス通路下流側接続部９よりも排気下流側に排気浄化用の触媒１０が配置されている。   An exhaust purification catalyst 10 is disposed on the exhaust downstream side of the bypass passage downstream connection portion 9 located on the exhaust downstream side of the turbine rotor 3 in the connection position between the bypass passage 4 and the exhaust passage 2.

ＥＧＲ通路６におけるＥＧＲクーラ７とＥＧＲ弁８との間の区間と、バイパス通路４におけるウエストゲート弁５よりも排気上流側の区間とは、連絡通路１１により連通するよう構成されている。   A section between the EGR cooler 7 and the EGR valve 8 in the EGR passage 6 and a section on the exhaust upstream side of the waste gate valve 5 in the bypass passage 4 are configured to communicate with each other through a communication passage 11.

そして、ＥＧＲ通路６と排気通路２との接続位置となるＥＧＲ通路接続部１２には、３方向の流れを制御可能な第１方向制御手段としての第１三方弁１３が配置されている。換言すれば、第１方向制御手段である第１三方弁１３は、流体の出入り口が３つあり、これら３つの出入り口の内の少なくとも２つを出入り口とする複数の流路の切り替えを行うものである。詳述すると、排気通路２のうち、ＥＧＲ通路接続部１２よりも排気上流側の位置をＡ、排気下流側の位置をＣとし、排気通路２に接続されたＥＧＲ通路６の一端位置をＢとすると、この第１三方弁１３は、Ａ〜Ｂ間の流れのみを許容する場合と、Ａ〜Ｃ間の流れのみを許容する場合と、Ａ〜Ｂ間及びＡ〜Ｃ間の流れを同時に許容する場合と、に切り替られるように構成されている。   A first three-way valve 13 serving as a first direction control means capable of controlling the flow in three directions is disposed in the EGR passage connection portion 12 serving as a connection position between the EGR passage 6 and the exhaust passage 2. In other words, the first three-way valve 13 as the first direction control means has three fluid inlets and outlets, and switches a plurality of flow paths having at least two of these three inlets as inlets and outlets. is there. Specifically, in the exhaust passage 2, the position on the exhaust upstream side of the EGR passage connection portion 12 is A, the position on the exhaust downstream side is C, and one end position of the EGR passage 6 connected to the exhaust passage 2 is B. Then, this first three-way valve 13 allows only the flow between A and B, allows only the flow between A and C, and allows the flow between A and B and between A and C at the same time. It is comprised so that it may be switched to.

また、バイパス通路４と排気通路２との接続位置のうち、タービンロータ３の排気上流側に位置するバイパス通路上流側接続部１４には、３方向の流れを制御可能な第２方向制御手段としての第２三方弁１５が配置されている。換言すれば、第２方向制御手段である第２三方弁１５は、流体の出入り口が３つあり、これら３つの出入り口の内の少なくとも２つを出入り口とする複数の流路の切り替えを行うものである。詳述すると、排気通路２のうち、バイパス通路上流側接続部１４よりも排気上流側の位置をＤ、排気下流側の位置をＦとし、排気通路２に接続されたバイパス通路４の排気上流側端位置をＥとすると、この第２三方弁１５は、Ｄ〜Ｅ間の流れのみを許容する場合と、Ｅ〜Ｆ間の流れのみを許容する場合と、Ｄ〜Ｆ間の流れのみを許容する場合と、Ｄ〜Ｅ間及びＤ〜Ｆ間の流れを同時に許容する場合と、に切り替られるように構成されている。   Of the connecting positions of the bypass passage 4 and the exhaust passage 2, the bypass passage upstream connection portion 14 located on the exhaust upstream side of the turbine rotor 3 has second direction control means capable of controlling the flow in three directions. The second three-way valve 15 is arranged. In other words, the second three-way valve 15 as the second direction control means has three fluid inlets and outlets, and switches a plurality of flow paths having at least two of these three inlets as inlets and outlets. is there. Specifically, in the exhaust passage 2, the position upstream of the bypass passage upstream side connection portion 14 is D, the position of the exhaust downstream side is F, and the exhaust upstream side of the bypass passage 4 connected to the exhaust passage 2. When the end position is E, the second three-way valve 15 allows only the flow between D and E, allows only the flow between E and F, and allows only the flow between D and F. And a case where flows between D and E and between D and F are allowed at the same time.

このように構成された本実施形態においては、運転状態に応じて、ウエストゲート弁５、ＥＧＲ弁８、第１三方弁１３、第２三方弁１５の設定が変更され、排気ガスの流れを最適化することができ、内燃機関の運転性能を早期に、かつ効果的に最大限引き出すことが可能となる。   In the present embodiment configured as described above, the settings of the waste gate valve 5, the EGR valve 8, the first three-way valve 13, and the second three-way valve 15 are changed according to the operation state, and the flow of exhaust gas is optimized. Therefore, the operating performance of the internal combustion engine can be maximized quickly and effectively.

例えば、冷機状態から内燃機関１を始動する際には、触媒１０の可及的速やかな活性化を図る必要がある。そこで、冷機始動時には、図２及び図３に示すように、触媒１０が活性化温度に到達するまで、すなわち始動から時刻Ｔ１までの期間は、ＥＧＲクーラ７及びタービンロータ３をバイパスした排気ガスが触媒１０に導入されるように、ウエストゲート弁５、ＥＧＲ弁８、第１三方弁１３、第２三方弁１５を制御する。   For example, when starting the internal combustion engine 1 from a cold state, it is necessary to activate the catalyst 10 as quickly as possible. Therefore, at the time of cold start, as shown in FIG. 2 and FIG. 3, the exhaust gas bypassing the EGR cooler 7 and the turbine rotor 3 is exhausted until the catalyst 10 reaches the activation temperature, that is, from the start to the time T1. The waste gate valve 5, the EGR valve 8, the first three-way valve 13, and the second three-way valve 15 are controlled so as to be introduced into the catalyst 10.

具体的には、冷機始動時には、ＥＧＲ通路接続部１２よりも排気上流側の排気通路２からＥＧＲ通路接続部１２を経てＥＧＲ通路接続部１２よりも排気下流側の排気通路２へと流れる排気ガスの流れのみが許容されるように第１三方弁１３が切り替えられ、バイパス通路上流側接続部１４よりも排気上流側の排気通路２からバイパス通路上流側接続部１４を経てバイパス通路４へと流れる排気ガスの流れのみが許容されるよう第２三方弁１５が切り替えられ、ＥＧＲ弁８が全閉状態となり、ウエストゲート弁５が全開状態となるよう制御されている。換言すれば、第１三方弁１３はＡ〜Ｃ間の流れのみが許容されるよう切り替えられ、第２三方弁１５によりＤ〜Ｅ間の流れのみが許容されるよう切り替えられている。尚、図３において、網掛けされた経路は、排気ガスが流れる経路を示している。   Specifically, at the time of cold start, exhaust gas that flows from the exhaust passage 2 upstream of the EGR passage connection 12 through the EGR passage connection 12 to the exhaust passage 2 downstream of the EGR passage connection 12 from the EGR passage connection 12 The first three-way valve 13 is switched so that only the flow of the exhaust gas is allowed to flow from the exhaust passage 2 on the exhaust upstream side of the bypass passage upstream side connection portion 14 to the bypass passage 4 via the bypass passage upstream side connection portion 14. The second three-way valve 15 is switched so that only the flow of exhaust gas is allowed, the EGR valve 8 is fully closed, and the wastegate valve 5 is controlled to be fully open. In other words, the first three-way valve 13 is switched so that only the flow between A and C is allowed, and the second three-way valve 15 is switched so that only the flow between D and E is allowed. In FIG. 3, the shaded path indicates the path through which the exhaust gas flows.

この図３のように、ウエストゲート弁５、ＥＧＲ弁８、第１三方弁１３、第２三方弁１５を制御すれば、無駄な熱損失がないまま排気ガスが触媒１０に到達することになるので、触媒１０の可及的速やかな活性化を図ることができる。   As shown in FIG. 3, if the wastegate valve 5, the EGR valve 8, the first three-way valve 13, and the second three-way valve 15 are controlled, the exhaust gas reaches the catalyst 10 without wasteful heat loss. Therefore, the catalyst 10 can be activated as quickly as possible.

また、触媒１０が活性化温度に達した冷機状態においては、冷却水温度の早期に上昇させることで、暖機の促進化やＥＧＲが実施可能な冷却水温度へ早期に到達させる必要がある。   Further, in the cold state where the catalyst 10 has reached the activation temperature, it is necessary to quickly reach the cooling water temperature at which promotion of warm-up and EGR can be performed by raising the cooling water temperature early.

そこで、触媒１０活性化後の冷機時には、図４〜図６に示すように、冷却水温度がＥＧＲの実施可能な所定温度Ｋ（例えば６０℃）となるまで（Ｔ１〜Ｔ２間）、ＥＧＲクーラ７を通った排気ガスが触媒１０へ導入されるように、ウエストゲート弁５、ＥＧＲ弁８、第１三方弁１３、第２三方弁１５を制御する。   Therefore, at the time of cooling after activation of the catalyst 10, as shown in FIGS. 4 to 6, until the cooling water temperature reaches a predetermined temperature K (for example, 60 ° C.) at which EGR can be performed (between T1 and T2), the EGR cooler. The waste gate valve 5, the EGR valve 8, the first three-way valve 13, and the second three-way valve 15 are controlled so that the exhaust gas that has passed through 7 is introduced into the catalyst 10.

具体的には、加速要求の無い場合には、図５に示すように、ＥＧＲ通路接続部１２よりも排気上流側の排気通路２からＥＧＲ通路接続部１２を経てＥＧＲ通路６へと流れる排気ガスの流れのみが許容されるように第１三方弁１３が切り替えられ、バイパス通路上流側接続部１４よりも排気上流側の排気通路２からバイパス通路上流側接続部１４を経てバイパス通路上流側接続部１４よりも排気下流側の排気通路２へと流れる排気ガスの流れのみが許容されるよう第２三方弁１５が切り替えられ、ＥＧＲ弁８が全閉状態となり、ウエストゲート弁５が全開状態となるよう制御されている。換言すれば、第１三方弁１３はＡ〜Ｂ間の流れのみが許容されるよう切り替えられ、第２三方弁１５によりＤ〜Ｆ間の流れのみが許容されるよう切り替えられており、実質的に排気ガスがタービンロータ３をバイパスして触媒１０に導入されるようになっている。尚、図５において、網掛けされた経路は、排気ガスが流れる経路を示している。   Specifically, when there is no acceleration request, as shown in FIG. 5, the exhaust gas flowing from the exhaust passage 2 upstream of the EGR passage connecting portion 12 to the EGR passage 6 through the EGR passage connecting portion 12 as shown in FIG. The first three-way valve 13 is switched so that only the flow of the exhaust gas is allowed, and the bypass passage upstream connection portion from the exhaust passage 2 upstream of the bypass passage upstream from the bypass passage upstream passage 14 through the bypass passage upstream connection portion 14. The second three-way valve 15 is switched so that only the flow of the exhaust gas flowing to the exhaust passage 2 downstream of the exhaust gas 14 is allowed, the EGR valve 8 is fully closed, and the waste gate valve 5 is fully open. It is controlled as follows. In other words, the first three-way valve 13 is switched so that only the flow between A and B is allowed, and the second three-way valve 15 is switched so that only the flow between D and F is allowed, substantially. The exhaust gas bypasses the turbine rotor 3 and is introduced into the catalyst 10. In FIG. 5, the shaded paths indicate the paths through which the exhaust gas flows.

この図５のように、ウエストゲート弁５、ＥＧＲ弁８、第１三方弁１３、第２三方弁１５を制御すれば、ＥＧＲクーラ７にて排気ガスと冷却水との間の熱交換が行えるので、温度の上昇した冷却水による暖機の促進と、ＥＧＲが実施可能となる冷却水温度への早期の到達が実現でき、結果として燃費向上効果を得ることができる。   As shown in FIG. 5, if the waste gate valve 5, the EGR valve 8, the first three-way valve 13, and the second three-way valve 15 are controlled, the EGR cooler 7 can exchange heat between the exhaust gas and the cooling water. Therefore, promotion of warm-up by the cooling water whose temperature has increased and early arrival at the cooling water temperature at which EGR can be performed can be realized, and as a result, an improvement in fuel efficiency can be obtained.

また、加速要求がある場合には、図６に示すように、ＥＧＲ通路接続部１２よりも排気上流側の排気通路２からＥＧＲ通路接続部１２を経てＥＧＲ通路６へと流れる排気ガスの流れのみが許容されるように第１三方弁１３が切り替えられ、バイパス通路４からバイパス通路上流側接続部１４を経てバイパス通路上流側接続部１４よりも排気下流側の排気通路２へと流れる排気ガスの流れのみが許容されるよう第２三方弁１５が切り替えられ、ＥＧＲ弁８が全閉状態となり、ウエストゲート弁５が運転状態に応じて決まる過給圧の設定上限値を超えないように過給圧制御（デューティ制御）されている。換言すれば、第１三方弁１３はＡ〜Ｂ間の流れのみが許容されるよう切り替えられ、第２三方弁１５によりＥ〜Ｆ間の流れのみが許容されるよう切り替えられ、タービンロータ３に排気ガスの一部が導入されるようになっている。尚、図６において、網掛けされた経路は、排気ガスが流れる経路を示している。   Further, when there is an acceleration request, only the flow of exhaust gas flowing from the exhaust passage 2 upstream of the EGR passage connection 12 to the EGR passage 6 through the EGR passage connection portion 12 as shown in FIG. The first three-way valve 13 is switched so as to allow the exhaust gas flowing from the bypass passage 4 to the exhaust passage 2 downstream of the bypass passage upstream connection portion 14 through the bypass passage upstream connection portion 14. The second three-way valve 15 is switched so that only the flow is allowed, the EGR valve 8 is fully closed, and the wastegate valve 5 is supercharged so as not to exceed the set upper limit value of the supercharging pressure determined according to the operating state. Pressure control (duty control) is performed. In other words, the first three-way valve 13 is switched so that only the flow between A and B is allowed, and the second three-way valve 15 is switched so that only the flow between E and F is allowed. Part of the exhaust gas is introduced. In FIG. 6, the shaded paths indicate the paths through which the exhaust gas flows.

この図６のように、ウエストゲート弁５、ＥＧＲ弁８、第１三方弁１３、第２三方弁１５を制御すれば、排気タービン式過給機の駆動により加速要求に対応しつつ、冷却水温度の上昇を図ることができる。   As shown in FIG. 6, if the waste gate valve 5, EGR valve 8, first three-way valve 13, and second three-way valve 15 are controlled, the cooling water The temperature can be increased.

また、早急な過給圧の立ち上がりが必要とされる場合には、図７〜図９に示すように、ＥＧＲクーラ７等の過給圧の上昇に寄与しない部分に排気ガスを流すことなく、タービンロータ３の駆動に寄与する部分に集中して排気ガスが流れるように、ウエストゲート弁５、ＥＧＲ弁８、第１三方弁１３、第２三方弁１５を制御する。   Further, in the case where a rapid rise in the supercharging pressure is required, as shown in FIGS. 7 to 9, the exhaust gas does not flow through a portion that does not contribute to the increase in the supercharging pressure, such as the EGR cooler 7. The waste gate valve 5, the EGR valve 8, the first three-way valve 13, and the second three-way valve 15 are controlled so that exhaust gas flows in a concentrated manner in a portion that contributes to driving of the turbine rotor 3.

具体的には、過給圧のコントロールを開始するいわゆるインターセプトポイント前の状態（図７においてエンジン回転数がＲ１以下となる領域）では、図８に示すように、ＥＧＲ通路接続部１２よりも排気上流側の排気通路２からＥＧＲ通路接続部１２を経てＥＧＲ通路接続部１２よりも排気下流側の排気通路２へと流れる排気ガスの流れのみが許容されるように第１三方弁１３が切り替えられ、バイパス通路上流側接続部１４よりも排気上流側の排気通路２からバイパス通路上流側接続部１４を経てバイパス通路上流側接続部１４よりも排気下流側の排気通路２へと流れる排気ガスの流れのみが許容されるよう第２三方弁１５が切り替えられ、ＥＧＲ弁８が全閉状態となり、ウエストゲート弁５が全開状態となるよう制御されている。換言すれば、第１三方弁１３はＡ〜Ｃ間の流れのみが許容されるよう切り替えられ、第２三方弁１５によりＤ〜Ｆ間の流れのみが許容されるよう切り替えられている。尚、図８において、網掛けされた経路は、排気ガスが流れる経路を示している。   Specifically, in a state before the so-called intercept point at which the control of the supercharging pressure is started (a region where the engine speed is R1 or less in FIG. 7), as shown in FIG. The first three-way valve 13 is switched so that only the flow of the exhaust gas flowing from the upstream exhaust passage 2 through the EGR passage connection portion 12 to the exhaust passage 2 downstream of the EGR passage connection portion 12 is allowed. The flow of exhaust gas flowing from the exhaust passage 2 upstream of the bypass passage upstream connection portion 14 through the bypass passage upstream connection portion 14 to the exhaust passage 2 downstream of the bypass passage upstream connection portion 14. The second three-way valve 15 is switched such that only the EGR valve 8 is permitted, the EGR valve 8 is fully closed, and the wastegate valve 5 is controlled to be fully open. In other words, the first three-way valve 13 is switched so that only the flow between A and C is allowed, and the second three-way valve 15 is switched so that only the flow between D and F is allowed. In FIG. 8, the shaded paths indicate the paths through which the exhaust gas flows.

ここで、上述したインターセプトポイントとは、過給圧のコントロールを開始する時期のことであり、全負荷（アクセル全開）条件でエンジン回転数を上げていった際に、これ以上過給圧が上がらなくなるよう設定されるポイントである。具体的には、図７におけるＰ点がインターセプトポイントとなる。   Here, the above-mentioned intercept point is the timing when the control of the supercharging pressure is started, and when the engine speed is increased under the full load (accelerator fully open) condition, the supercharging pressure further increases. It is a point that is set to disappear. Specifically, point P in FIG. 7 is the intercept point.

この図８のように、ウエストゲート弁５、ＥＧＲ弁８、第１三方弁１３、第２三方弁１５を制御すれば、インターセプトポイント前の状態では、全ての排気ガスがタービンロータに導入されることになり、可及的速やかに過給圧を上昇させることができる。   As shown in FIG. 8, if the wastegate valve 5, the EGR valve 8, the first three-way valve 13, and the second three-way valve 15 are controlled, all exhaust gas is introduced into the turbine rotor before the intercept point. As a result, the supercharging pressure can be increased as quickly as possible.

そして、過給圧のコントロールを開始するいわゆるインターセプトポイント後の状態（図７においてエンジン回転数がＲ１より大きくなる領域）では、図９に示すように、ＥＧＲ通路接続部１２よりも排気上流側の排気通路２からＥＧＲ通路接続部１２を経てＥＧＲ通路接続部１２よりも排気下流側の排気通路２へと流れる排気ガスの流れのみが許容されるように第１三方弁１３が切り替えられ、バイパス通路上流側接続部１４よりも排気上流側の排気通路２からバイパス通路上流側接続部１４を経てバイパス通路４及びバイパス通路上流側接続部１４よりも排気下流側の排気通路２へと流れる排気ガスの流れのみが許容されるよう第２三方弁１５が切り替えられ、ＥＧＲ弁８が全閉状態となり、ウエストゲート弁５がウエストゲート弁５が運転状態に応じて決まる過給圧の設定上限値を超えないように過給圧制御（デューティ制御）されている。換言すれば、第１三方弁１３はＡ〜Ｃ間の流れのみが許容されるよう切り替えられ、第２三方弁１５によりＤ〜Ｅ間の流れ及びＤ〜Ｆ間の流れが同時に許容されるよう切り替えられている。尚、図９において、網掛けされた経路は、排気ガスが流れる経路を示している。   In a state after the so-called intercept point where the control of the supercharging pressure is started (a region where the engine speed is larger than R1 in FIG. 7), as shown in FIG. 9, the exhaust gas upstream side of the EGR passage connecting portion 12 is provided. The first three-way valve 13 is switched so that only the flow of the exhaust gas flowing from the exhaust passage 2 through the EGR passage connecting portion 12 to the exhaust passage 2 downstream of the EGR passage connecting portion 12 is allowed, and the bypass passage Exhaust gas flowing from the exhaust passage 2 upstream of the upstream connection portion 14 to the bypass passage 4 and the exhaust passage 2 downstream of the bypass passage upstream connection portion 14 via the bypass passage upstream connection portion 14. The second three-way valve 15 is switched so that only the flow is allowed, the EGR valve 8 is fully closed, and the wastegate valve 5 is turned on. Rolling state supercharging pressure control so as not to exceed the set upper limit value of the determined boost pressure in response to being (duty control). In other words, the first three-way valve 13 is switched to allow only the flow between A and C, and the second three-way valve 15 allows the flow between D and E and the flow between D and F at the same time. It has been switched. In FIG. 9, the shaded paths indicate the paths through which the exhaust gas flows.

この図９のように、ウエストゲート弁５、ＥＧＲ弁８、第１三方弁１３、第２三方弁１５を制御すれば、インターセプトポイント後の状態では、過給圧が所定の設定上限値を超えないようにウエストゲート弁が制御されるので、タービンロータ３に対して適正な量の排気ガスを導入することができる。   As shown in FIG. 9, if the waste gate valve 5, EGR valve 8, first three-way valve 13, and second three-way valve 15 are controlled, the supercharging pressure exceeds a predetermined set upper limit value after the intercept point. Since the wastegate valve is controlled so that there is no exhaust gas, an appropriate amount of exhaust gas can be introduced into the turbine rotor 3.

そして、ＥＧＲを実施する際には、図１０〜図１２に示すように、吸気系に還流させる排気ガス（ＥＧＲガス）の温度が運転状態に応じて変更されるように、ウエストゲート弁５、ＥＧＲ弁８、第１三方弁１３、第２三方弁１５を制御する。   When performing EGR, as shown in FIGS. 10 to 12, the wastegate valve 5, so that the temperature of the exhaust gas (EGR gas) recirculated to the intake system is changed according to the operating state. The EGR valve 8, the first three-way valve 13, and the second three-way valve 15 are controlled.

具体的には、運転状態が低負荷領域でＥＧＲを実施する際には、図１１に示すように、ＥＧＲ通路接続部１２よりも排気上流側の排気通路２からＥＧＲ通路接続部１２を経てＥＧＲ通路接続部１２よりも排気下流側の排気通路２へと流れる排気ガスの流れのみが許容されるように第１三方弁１３が切り替えられ、バイパス通路上流側接続部１４よりも排気上流側の排気通路２からバイパス通路上流側接続部１４を経てバイパス通路４へと流れる排気ガスの流れのみが許容されるよう第２三方弁１５が切り替えられ、ＥＧＲ弁が運転状態に応じた排気ガスの還流量となるようデューティ制御され、ウエストゲート弁５が全開状態となるよう制御されている。換言すれば、第１三方弁１３はＡ〜Ｃ間の流れのみが許容されるよう切り替えられ、第２三方弁１５によりＤ〜Ｅ間の流れのみが許容されるよう切り替えられている。尚、図１１において、網掛けされた経路は、排気ガスが流れる経路を示している。   Specifically, when the EGR is performed in the low load region of the operating state, as shown in FIG. 11, the EGR from the exhaust passage 2 upstream of the EGR passage connecting portion 12 through the EGR passage connecting portion 12. The first three-way valve 13 is switched so that only the flow of the exhaust gas flowing to the exhaust passage 2 downstream of the passage connection 12 is permitted, and the exhaust upstream of the bypass passage upstream connection 14 is exhausted. The second three-way valve 15 is switched so that only the flow of the exhaust gas flowing from the passage 2 to the bypass passage 4 through the bypass passage upstream side connection portion 14 is allowed, and the EGR valve recirculates the exhaust gas according to the operating state. The waste gate valve 5 is controlled to be fully opened. In other words, the first three-way valve 13 is switched so that only the flow between A and C is allowed, and the second three-way valve 15 is switched so that only the flow between D and E is allowed. In FIG. 11, the shaded paths indicate the paths through which the exhaust gas flows.

この図１１のように、ウエストゲート弁５、ＥＧＲ弁８、第１三方弁１３、第２三方弁１５を制御すれば、運転状態が低負荷域でＥＧＲを実施する際には、ＥＧＲクーラ７をバイパスすることで比較的温度が高い排気ガスをＥＧＲガスとして吸気系に還流させることができる。つまり、比較的温度の高いＥＧＲガスが要求される低負荷運転領域では、運転状態にあった比較的高温のＥＧＲガスを吸気系に導入することができる。   As shown in FIG. 11, if the waste gate valve 5, the EGR valve 8, the first three-way valve 13, and the second three-way valve 15 are controlled, the EGR cooler 7 By bypassing the exhaust gas, the exhaust gas having a relatively high temperature can be recirculated to the intake system as EGR gas. That is, in a low load operation region where EGR gas having a relatively high temperature is required, it is possible to introduce a relatively high temperature EGR gas in an operating state into the intake system.

そして、運転状態が高負荷域でＥＧＲを実施する際には、図１２に示すように、ＥＧＲ通路接続部１２よりも排気上流側の排気通路２からＥＧＲ通路接続部１２を経てＥＧＲ通路６へと流れる排気ガスの流れとＥＧＲ通路接続部１２よりも排気下流側の排気通路２へと流れる排気ガスの流れの双方が許容されるように第１三方弁１３が切り替えられ、バイパス通路上流側接続部１４よりも排気上流側の排気通路２からバイパス通路上流側接続部１４を経てバイパス通路上流側接続部１４よりも排気下流側の排気通路２へと流れる排気ガスの流れのみが許容されるよう第２三方弁１５が切り替えられ、ＥＧＲ弁が運転状態に応じた排気ガスの還流量となるようデューティ制御され、ウエストゲート弁５がウエストゲート弁５が運転状態に応じて決まる過給圧の設定上限値を超えないように過給圧制御（デューティ制御）されている。換言すれば、第１三方弁１３はＡ〜Ｂ間の流れ及びＡ〜Ｃ間の流れが同時に許容されるよう切り替えられ、第２三方弁１５によりＤ〜Ｆ間の流れのみが許容されるよう切り替えられている。尚、図１２において、網掛けされた経路は、排気ガスが流れる経路を示している。   When the EGR is performed in the high load region, as shown in FIG. 12, the exhaust gas passage 2 upstream of the EGR passage connection portion 12 passes through the EGR passage connection portion 12 to the EGR passage 6 as shown in FIG. 12. The first three-way valve 13 is switched so that both the flow of exhaust gas flowing through and the flow of exhaust gas flowing into the exhaust passage 2 downstream of the EGR passage connecting portion 12 are allowed, and the bypass passage upstream connection Only the flow of exhaust gas flowing from the exhaust passage 2 upstream of the exhaust passage 14 to the exhaust passage 2 downstream of the bypass passage upstream connection portion 14 via the bypass passage upstream connection portion 14 is allowed. The second three-way valve 15 is switched, the duty control is performed so that the EGR valve has an exhaust gas recirculation amount corresponding to the operating state, and the wastegate valve 5 is changed according to the operating state. Maru are set an upper limit supercharging pressure control so as not to exceed the boost pressure (duty control). In other words, the first three-way valve 13 is switched so that the flow between A and B and the flow between A and C are allowed at the same time, and only the flow between D and F is allowed by the second three-way valve 15. It has been switched. In FIG. 12, shaded paths indicate paths through which exhaust gas flows.

この図１２のように、ウエストゲート弁５、ＥＧＲ弁８、第１三方弁１３、第２三方弁１５を制御すれば、運転状態が高負荷域の状態でＥＧＲを実施する際には、ＥＧＲクーラ７に導入されることで冷却された比較的温度が低い排気ガスをＥＧＲガスとして吸気系に還流させることができる。つまり、比較的温度の低いＥＧＲガスが要求される高荷運転領域の運転状態の際には、運転状態にあった比較的低温のＥＧＲガスを吸気系に導入することができると共に、タービンロータ３にも排気ガスが導入されるので所望の過給圧を得ることができる。   As shown in FIG. 12, if the waste gate valve 5, the EGR valve 8, the first three-way valve 13, and the second three-way valve 15 are controlled, the EGR is performed when the operation state is a high load range. The exhaust gas cooled at a relatively low temperature by being introduced into the cooler 7 can be recirculated to the intake system as EGR gas. That is, in the operation state of the high load operation region where the EGR gas having a relatively low temperature is required, the relatively low temperature EGR gas in the operation state can be introduced into the intake system, and the turbine rotor 3 In addition, since the exhaust gas is introduced, a desired supercharging pressure can be obtained.

図１３は、上述した本実施形態の制御の流れを示すフローチャートである。   FIG. 13 is a flowchart showing the control flow of the present embodiment described above.

ステップ（以下、単にＳと表記する）１１では、触媒１０が活性化されているか否かを判定し、触媒１０が活性化されている場合にはＳ１３へ進み、触媒１０が活性化されていない場合にはＳ１２へ進む。   In step (hereinafter simply referred to as S) 11, it is determined whether or not the catalyst 10 is activated. If the catalyst 10 is activated, the process proceeds to S13, where the catalyst 10 is not activated. If so, the process proceeds to S12.

Ｓ１２では、第１三方弁１３がＡ〜Ｃ間の流れのみを許容するよう切り替えられ、第２三方弁１５がＤ〜Ｅ間の流れのみを許容するよう切り替えられ、ＥＧＲ弁８が閉、ウエストゲート弁５が開となるよう設定される。   In S12, the first three-way valve 13 is switched to allow only the flow between A and C, the second three-way valve 15 is switched to allow only the flow between D and E, the EGR valve 8 is closed, and the waist It is set so that the gate valve 5 is opened.

Ｓ１３では、冷却水温がＥＧＲ可能な水温となっているか否かを判定し、ＥＧＲ可能な水温となっている場合にはＳ１７へ進み、ＥＧＲ可能な水温となっていない場合にはＳ１４へ進む。   In S13, it is determined whether or not the cooling water temperature is an EGR-capable water temperature. If the cooling water temperature is an EGR-capable water temperature, the process proceeds to S17. If the EGR-capable water temperature is not achieved, the process proceeds to S14.

Ｓ１４では、過給領域であるか否かを判定し、過給領域であればＳ１５へ進み、過給領域でなければＳ１６へ進む。   In S14, it is determined whether or not it is the supercharging region. If it is the supercharging region, the process proceeds to S15, and if it is not the supercharging region, the process proceeds to S16.

Ｓ１５では、第１三方弁１３がＡ〜Ｂ間の流れのみを許容するよう切り替えられ、第２三方弁１５がＥ〜Ｆ間の流れのみを許容するよう切り替えられ、ＥＧＲ弁８が閉、ウエストゲート弁５が運転状態に応じて決まる過給圧の設定上限値を超えないようにデューティ制御されるよう設定される。一方、Ｓ１６では、第１三方弁１３がＡ〜Ｂ間の流れのみを許容するよう切り替えられ、第２三方弁１５がＤ〜Ｆ間の流れのみを許容するよう切り替えられ、ＥＧＲ弁８が閉、ウエストゲート弁５が開となるよう設定される。   In S15, the first three-way valve 13 is switched to allow only the flow between A and B, the second three-way valve 15 is switched to allow only the flow between E and F, the EGR valve 8 is closed, and the waist Duty control is set so that the gate valve 5 does not exceed the set upper limit value of the supercharging pressure determined according to the operating state. On the other hand, in S16, the first three-way valve 13 is switched so as to allow only the flow between A and B, the second three-way valve 15 is switched so as to allow only the flow between D and F, and the EGR valve 8 is closed. The waste gate valve 5 is set to be opened.

Ｓ１７では、ＥＧＲをＯＮするか否かを判定し、ＥＧＲをＯＮする場合にはＳ２１へ進み、ＥＧＲをＯＮしない場合にはＳ１８へ進む。   In S17, it is determined whether or not the EGR is turned on. If the EGR is turned on, the process proceeds to S21. If the EGR is not turned on, the process proceeds to S18.

Ｓ１８では、運転状態がインターセプトポイント前の状態であるか否かを判定し、インターセプトポイント前であればＳ１９へ進み、インターセプトポイント後であればＳ２０へ進む。   In S18, it is determined whether or not the driving state is a state before the intercept point. If it is before the intercept point, the process proceeds to S19, and if it is after the intercept point, the process proceeds to S20.

Ｓ１９では、第１三方弁１３がＡ〜Ｃ間の流れのみを許容するよう切り替えられ、第２三方弁１５がＤ〜Ｆ間の流れのみを許容するよう切り替えられ、ＥＧＲ弁８が閉、ウエストゲート弁５が開となるよう設定される。一方Ｓ２０では、第１三方弁１３がＡ〜Ｃ間の流れのみを許容するよう切り替えられ、第２三方弁１５がＤ〜Ｅ間及びＤ〜Ｆ間の流れを同時に許容するよう切り替えられ、ＥＧＲ弁８が閉、ウエストゲート弁５が運転状態に応じて決まる過給圧の設定上限値を超えないようにデューティ制御されるよう設定される。   In S19, the first three-way valve 13 is switched so as to allow only the flow between A and C, the second three-way valve 15 is switched so as to allow only the flow between D and F, the EGR valve 8 is closed, and the waist It is set so that the gate valve 5 is opened. On the other hand, in S20, the first three-way valve 13 is switched so as to allow only the flow between A and C, and the second three-way valve 15 is switched so as to allow the flow between D and E and between D and F at the same time, and EGR The valve 8 is closed, and the wastegate valve 5 is set to be duty-controlled so as not to exceed the set upper limit value of the supercharging pressure determined according to the operating state.

Ｓ２１では、吸気系に還流される排気ガスの温度を制御するにあたり、運転状態が低負荷域であるか否かを判定し、低負荷域であればＳ２２へ、低負荷域でなければ（高負荷域であれば）Ｓ２３へ進む。   In S21, in controlling the temperature of the exhaust gas recirculated to the intake system, it is determined whether or not the operating state is a low load region. If it is a load range, the process proceeds to S23.

Ｓ２２では、第１三方弁１３がＡ〜Ｃ間の流れのみを許容するよう切り替えられ、第２三方弁１５がＤ〜Ｅ間の流れのみを許容するよう切り替えられ、ＥＧＲ弁８が運転状態に応じた排気ガスの還流量となるようデューティ制御され、ウエストゲート弁５が開となるよう設定される。一方、Ｓ２３では、第１三方弁１３がＡ〜Ｂ間の流れのみを許容するよう切り替えられ、第２三方弁１５がＤ〜Ｆ間の流れのみを許容するよう切り替えられ、ＥＧＲ弁８が運転状態に応じた排気ガスの還流量となるようデューティ制御され、ウエストゲート弁５が運転状態に応じて決まる過給圧の設定上限値を超えないようにデューティ制御されるよう設定される。   In S22, the first three-way valve 13 is switched so as to allow only the flow between A and C, the second three-way valve 15 is switched so as to allow only the flow between D and E, and the EGR valve 8 is in the operating state. The duty control is performed so that the exhaust gas recirculation amount is adjusted, and the waste gate valve 5 is set to be opened. On the other hand, in S23, the first three-way valve 13 is switched so as to allow only the flow between A and B, the second three-way valve 15 is switched so as to allow only the flow between D and F, and the EGR valve 8 is operated. The duty control is performed so that the exhaust gas recirculation amount corresponds to the state, and the waste gate valve 5 is set to be duty controlled so as not to exceed the set upper limit value of the supercharging pressure determined according to the operation state.

尚、上述した実施形態においては、第１及び第２方向制御手段は三方弁に限定されるのではなく、上述した実施形態で求められるような切替ができるものであればよい。   In the above-described embodiment, the first and second direction control means are not limited to the three-way valve, but may be any one that can be switched as required in the above-described embodiment.

上記実施形態から把握し得る本発明の技術的思想について、その効果とともに列記する。   The technical idea of the present invention that can be grasped from the above embodiment will be listed together with the effects thereof.

（１） 同一軸に取り付けたタービンロータ及びコンプレッサロータを有する排気タービン式過給機のタービンロータが配置された排気通路と、タービンロータをバイパスするよう排気通路に接続されたバイパス通路と、バイパス通路内に配置されたウエストゲート弁と、排気通路に対するバイパス通路の接続位置よりも排気上流側で排気通路に対して接続され、排気通路内の排気ガスを吸気系に導入するＥＧＲ通路と、ＥＧＲ通路に配置されたＥＧＲクーラと、ＥＧＲクーラよりもＥＧＲ通路における排気下流側に配置され吸気系に導入される排気ガス導入量を制御するＥＧＲ弁と、を備えた内燃機関の排気装置において、ＥＧＲ通路と排気通路との接続位置となるＥＧＲ通路接続部に３方向の流れを制御可能な第１方向制御手段が配置され、バイパス通路と排気通路との接続位置のうち、タービンロータの排気上流側に位置するバイパス通路上流側接続部に３方向の流れを制御可能な第２方向制御手段が配置され、ＥＧＲ通路におけるＥＧＲクーラとＥＧＲ弁との間の区間と、バイパス通路におけるウエストゲート弁よりも排気上流側の区間との間を連通させる連絡通路が設けられている。   (1) An exhaust passage in which a turbine rotor of an exhaust turbine supercharger having a turbine rotor and a compressor rotor attached to the same shaft is disposed, a bypass passage connected to the exhaust passage so as to bypass the turbine rotor, and a bypass passage An EGR passage that is connected to the exhaust passage upstream of the connection position of the bypass passage to the exhaust passage and introduces exhaust gas in the exhaust passage into the intake system, and an EGR passage. In an exhaust system for an internal combustion engine, the EGR passage includes: an EGR cooler that is disposed in the EGR passage; and an EGR valve that is disposed downstream of the EGR passage in the EGR passage and controls an exhaust gas introduction amount introduced into the intake system. The first direction control means capable of controlling the flow in the three directions is arranged at the EGR passage connecting portion which is a connection position between the exhaust passage and the exhaust passage. Among the connection positions of the bypass passage and the exhaust passage, the second direction control means capable of controlling the flow in the three directions is arranged at the bypass passage upstream side connection portion located on the exhaust upstream side of the turbine rotor, and the EGR in the EGR passage A communication passage is provided that communicates between the section between the cooler and the EGR valve and the section upstream of the wastegate valve in the bypass passage.

これによって、運転状態に応じて、第１及び第２方向制御手段、ＥＧＲ弁及びウエストゲート弁を制御することで、排気ガスの流れを最適化することができ、内燃機関の運転性能を早期に最大限引き出すことが可能となる。   Thereby, the flow of exhaust gas can be optimized by controlling the first and second direction control means, the EGR valve and the wastegate valve according to the operating state, and the operating performance of the internal combustion engine can be improved early. It is possible to draw out as much as possible.

（２） 上記（１）に記載の内燃機関の排気装置において、バイパス通路と排気通路との接続位置のうちタービンロータの排気下流側に位置するバイパス通路下流側接続部よりも排気下流側に排気浄化用の触媒が配置され、冷機始動時には、ＥＧＲ通路接続部よりも排気上流側の排気通路からＥＧＲ通路接続部を経てＥＧＲ通路接続部よりも排気下流側の排気通路へと流れる排気ガスの流れのみが許容されるように第１方向制御手段が設定され、バイパス通路上流側接続部よりも排気上流側の排気通路からバイパス通路上流側接続部を経てバイパス通路へと流れる排気ガスの流れのみが許容されるよう第２方向制御手段が設定され、ＥＧＲ弁が閉弁され、ウエストゲート弁が開弁されるよう設定されている。   (2) In the exhaust system for an internal combustion engine according to (1), the exhaust gas is exhausted more downstream than the bypass passage downstream connection portion located on the exhaust downstream side of the turbine rotor in the connection position between the bypass passage and the exhaust passage. At the time of cold start, an exhaust gas flow that flows from the exhaust passage upstream of the EGR passage to the exhaust passage downstream of the EGR passage connecting portion through the EGR passage connecting portion when the cooler is started The first direction control means is set such that only the flow of exhaust gas flowing from the exhaust passage upstream of the bypass passage to the bypass passage through the bypass passage upstream connection portion than the bypass passage upstream connection portion is set. The second direction control means is set so as to be allowed, the EGR valve is closed, and the waste gate valve is opened.

これによって、冷機始動時には、ＥＧＲクーラ及びタービンロータをバイパスした排気ガスを触媒に導入することができ、最も効率よく触媒を活性化させることができる。   Thereby, at the time of cold start, the exhaust gas bypassing the EGR cooler and the turbine rotor can be introduced into the catalyst, and the catalyst can be activated most efficiently.

（３） 上記（１）または（２）に記載の内燃機関の排気装置において、冷機状態で加速要求がある場合には、ＥＧＲ通路接続部よりも排気上流側の排気通路からＥＧＲ通路接続部を経てＥＧＲ通路へと流れる排気ガスの流れのみが許容されるように第１方向制御手段が設定され、バイパス通路からバイパス通路上流側接続部を経てタービンロータへと流れる排気ガスの流れのみが許容されるよう第２方向制御手段が設定され、ＥＧＲ弁が閉弁するよう設定され、ウエストゲート弁が運転状態に応じて決まる過給圧の設定上限値を超えないように過給圧制御をするよう設定されている。これによって、ＥＧＲクーラにて排気ガスの熱を回収することができる。つまり、ＥＧＲクーラにて排気ガスと冷却水との間で熱交換を行い、冷却水温度を効率よく上昇させることができる。   (3) In the exhaust system for an internal combustion engine according to (1) or (2), when there is a request for acceleration in a cold state, the EGR passage connection portion is connected from the exhaust passage upstream of the EGR passage connection portion. The first direction control means is set so that only the flow of exhaust gas flowing to the EGR passage is allowed, and only the flow of exhaust gas flowing from the bypass passage to the turbine rotor via the bypass passage upstream side connection portion is allowed. The second direction control means is set so that the EGR valve is closed, and the boost pressure control is performed so that the waste gate valve does not exceed the set upper limit value of the boost pressure determined according to the operating state. Is set. Thereby, the heat of the exhaust gas can be recovered by the EGR cooler. That is, heat exchange can be performed between the exhaust gas and the cooling water in the EGR cooler, and the cooling water temperature can be increased efficiently.

（４） 上記（１）〜（３）のいずれかに記載の内燃機関の排気装置において、低負荷運転時に高温の排気ガスを吸気系に還流させたい場合には、ＥＧＲ通路接続部よりも排気上流側の排気通路からＥＧＲ通路接続部を経てＥＧＲ通路接続部よりも排気下流側の排気通路へと流れる排気ガスの流れのみが許容されるように第１方向制御手段が設定され、バイパス通路上流側接続部よりも排気上流側の排気通路からバイパス通路接続部を経てバイパス通路へと流れる排気ガスの流れのみが許容されるよう第２方向制御手段が設定され、ＥＧＲ弁が運転状態に応じた排気ガスの還流量となるよう設定され、ウエストゲート弁が開弁するよう設定されている。これによって、低負荷運転時等の比較的高い温度の排気ガスを吸気系に還流させることが要求される際には、ＥＧＲクーラを介さずに排気ガスを吸気系に還流させると共に、ターボ過給器をバイパスして触媒に排気ガスを導入させることができる。   (4) In the exhaust system for an internal combustion engine according to any one of the above (1) to (3), when it is desired to return high-temperature exhaust gas to the intake system during low-load operation, the exhaust gas is exhausted more than the EGR passage connection portion. The first direction control means is set so that only the flow of the exhaust gas flowing from the upstream exhaust passage through the EGR passage connecting portion to the exhaust downstream side of the EGR passage connecting portion is allowed, and the bypass passage upstream The second direction control means is set so that only the flow of the exhaust gas flowing from the exhaust passage upstream of the side connection portion to the bypass passage through the bypass passage connection portion is allowed, and the EGR valve is set according to the operating state. The exhaust gas recirculation amount is set, and the wastegate valve is set to open. As a result, when it is required to return the exhaust gas having a relatively high temperature to the intake system during low load operation or the like, the exhaust gas is returned to the intake system without passing through the EGR cooler, and the turbocharging is performed. The exhaust gas can be introduced into the catalyst by bypassing the vessel.

本発明に係る内燃機関の排気装置の概略構成模式的に示した説明図。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 冷機始動時における触媒の温度上昇傾向を示す特性線図。The characteristic line figure which shows the temperature rise tendency of the catalyst at the time of cold start. 触媒が活性化温度に到達するまでの排気ガスの流れを模式的に示した説明図。Explanatory drawing which showed typically the flow of the exhaust gas until a catalyst reaches activation temperature. 冷機始動時における冷却水の温度上昇傾向を示す特性線図。The characteristic line figure which shows the temperature rise tendency of the cooling water at the time of cold machine starting. 触媒活性化後の冷機時で加速要求がない場合の排気ガスの流れを模式的に示した説明図。Explanatory drawing which showed typically the flow of the exhaust gas when there is no acceleration request | requirement at the time of the cold machine after catalyst activation. 触媒活性化後の冷機時で加速要求がある場合の排気ガスの流れを模式的に示した説明図。Explanatory drawing which showed typically the flow of exhaust gas when there exists an acceleration request | requirement at the time of the cold machine after catalyst activation. エンジン回転数と吸気圧の上限値との相関関係を模式的に示した説明図。Explanatory drawing which showed typically the correlation with an engine speed and the upper limit of intake pressure. インターセプトポイント前の状態で加速要求がある場合の排気ガスの流れを模式的に示した説明図。Explanatory drawing which showed typically the flow of the exhaust gas when there exists an acceleration request | requirement in the state before an intercept point. インターセプトポイント後の状態で加速要求がある場合の排気ガスの流れを模式的に示した説明図。Explanatory drawing which showed typically the flow of exhaust gas when there exists an acceleration request | requirement in the state after an intercept point. 高負荷領域と低負荷領域とを模式的に示した説明図。Explanatory drawing which showed the high load area | region and the low load area | region typically. 低負荷領域でＥＧＲを実施する場合の排気ガスの流れを模式的に示した説明図。Explanatory drawing which showed typically the flow of the exhaust gas in the case of implementing EGR in a low load area | region. 高負荷領域でＥＧＲを実施する場合の排気ガスの流れを模式的に示した説明図。Explanatory drawing which showed typically the flow of the exhaust gas in the case of implementing EGR in a high load area | region. 本実施形態の制御の流れを示すフローチャート。The flowchart which shows the flow of control of this embodiment.

符号の説明Explanation of symbols

２…排気通路
３…タービンロータ
４…バイパス通路
５…ウエストゲート弁
６…ＥＧＲ通路
７…ＥＧＲクーラ
８…ＥＧＲ弁
１０…触媒
１１…連絡通路
１３…第１三方弁（第１方向制御手段）
１５…第２三方弁（第２方向制御手段） 2 ... Exhaust passage 3 ... Turbine rotor 4 ... Bypass passage 5 ... Waist gate valve 6 ... EGR passage 7 ... EGR cooler 8 ... EGR valve 10 ... Catalyst 11 ... Communication passage 13 ... First three-way valve (first direction control means)
15 ... Second three-way valve (second direction control means)

Claims (4)

同一軸に取り付けたタービンロータ及びコンプレッサロータを有する排気タービン式過給機のタービンロータが配置された排気通路と、タービンロータをバイパスするよう排気通路に接続されたバイパス通路と、バイパス通路内に配置されたウエストゲート弁と、排気通路に対するバイパス通路の接続位置よりも排気上流側で排気通路に対して接続され、排気通路内の排気ガスを吸気系に導入するＥＧＲ通路と、ＥＧＲ通路に配置されたＥＧＲクーラと、ＥＧＲクーラよりもＥＧＲ通路における排気下流側に配置され吸気系に導入される排気ガス導入量を制御するＥＧＲ弁と、を備えた内燃機関の排気装置において、
ＥＧＲ通路と排気通路との接続位置となるＥＧＲ通路接続部に３方向の流れを制御可能な第１方向制御手段が配置され、
バイパス通路と排気通路との接続位置のうち、タービンロータの排気上流側に位置するバイパス通路上流側接続部に３方向の流れを制御可能な第２方向制御手段が配置され、
ＥＧＲ通路におけるＥＧＲクーラとＥＧＲ弁との間の区間と、バイパス通路におけるウエストゲート弁よりも排気上流側の区間との間を連通させる連絡通路が設けられていることを特徴とする内燃機関の排気装置。 An exhaust passage in which the turbine rotor of an exhaust turbine supercharger having a turbine rotor and a compressor rotor mounted on the same shaft is disposed, a bypass passage connected to the exhaust passage so as to bypass the turbine rotor, and disposed in the bypass passage The EGR passage, which is connected to the exhaust passage upstream of the connection position of the bypass passage to the exhaust passage and the exhaust passage, introduces exhaust gas in the exhaust passage into the intake system, and the EGR passage. An exhaust system for an internal combustion engine comprising: an EGR cooler; and an EGR valve that is disposed on the exhaust downstream side of the EGR passage relative to the EGR cooler and controls an amount of exhaust gas introduced into the intake system.
The first direction control means capable of controlling the flow in the three directions is arranged at the EGR passage connecting portion which is a connection position between the EGR passage and the exhaust passage,
Of the connection positions of the bypass passage and the exhaust passage, the second direction control means capable of controlling the flow in the three directions is arranged in the bypass passage upstream connection portion located on the exhaust upstream side of the turbine rotor,
Exhaust gas for an internal combustion engine, characterized in that a communication passage is provided for communicating between a section between the EGR cooler and the EGR valve in the EGR passage and a section in the bypass passage upstream of the wastegate valve. apparatus. バイパス通路と排気通路との接続位置のうちタービンロータの排気下流側に位置するバイパス通路下流側接続部よりも排気下流側に排気浄化用の触媒が配置され、
冷機始動時には、ＥＧＲ通路接続部よりも排気上流側の排気通路からＥＧＲ通路接続部を経てＥＧＲ通路接続部よりも排気下流側の排気通路へと流れる排気ガスの流れのみが許容されるように第１方向制御手段が設定され、バイパス通路上流側接続部よりも排気上流側の排気通路からバイパス通路上流側接続部を経てバイパス通路へと流れる排気ガスの流れのみが許容されるよう第２方向制御手段が設定され、ＥＧＲ弁が閉弁され、ウエストゲート弁が開弁されるよう設定されていることを特徴とする請求項１に記載の内燃機関の排気装置。 An exhaust purification catalyst is disposed on the exhaust downstream side of the bypass passage downstream connection portion located on the exhaust downstream side of the turbine rotor in the connection position between the bypass passage and the exhaust passage,
At the time of cold start, the exhaust gas flow from the exhaust passage upstream of the EGR passage connection to the exhaust passage downstream of the EGR passage connection through the EGR passage connection is permitted. Second direction control is set so that one-way control means is set and only the flow of the exhaust gas flowing from the exhaust passage upstream of the bypass passage upstream from the bypass passage upstream to the bypass passage via the bypass passage upstream connecting portion is allowed. 2. An exhaust system for an internal combustion engine according to claim 1, wherein the means is set, the EGR valve is closed, and the waste gate valve is opened. 冷機状態で加速要求がある場合には、ＥＧＲ通路接続部よりも排気上流側の排気通路からＥＧＲ通路接続部を経てＥＧＲ通路へと流れる排気ガスの流れのみが許容されるように第１方向制御手段が設定され、バイパス通路からバイパス通路上流側接続部を経てタービンロータへと流れる排気ガスの流れのみが許容されるよう第２方向制御手段が設定され、ＥＧＲ弁が閉弁するよう設定され、ウエストゲート弁が運転状態に応じて決まる過給圧の設定上限値を超えないように過給圧制御をするよう設定されていることを特徴とする請求項１または２に記載の内燃機関の排気装置。   When there is an acceleration request in the cold state, the first direction control is performed so that only the flow of the exhaust gas flowing from the exhaust passage upstream of the EGR passage connection to the EGR passage through the EGR passage connection is allowed. Means is set, the second direction control means is set so that only the flow of the exhaust gas flowing from the bypass passage through the bypass passage upstream side connection portion to the turbine rotor is allowed, and the EGR valve is set to close, The exhaust of the internal combustion engine according to claim 1 or 2, wherein the waste gate valve is set to perform a supercharging pressure control so as not to exceed a set upper limit value of a supercharging pressure determined according to an operating state. apparatus. 低負荷運転時に高温の排気ガスを吸気系に還流させたい場合には、ＥＧＲ通路接続部よりも排気上流側の排気通路からＥＧＲ通路接続部を経てＥＧＲ通路接続部よりも排気下流側の排気通路へと流れる排気ガスの流れのみが許容されるように第１方向制御手段が設定され、バイパス通路上流側接続部よりも排気上流側の排気通路からバイパス通路接続部を経てバイパス通路へと流れる排気ガスの流れのみが許容されるよう第２方向制御手段が設定され、ＥＧＲ弁が運転状態に応じた排気ガスの還流量となるよう設定され、ウエストゲート弁が開弁するよう設定されていることを特徴とする請求項１〜３のいずれかに記載の内燃機関の排気装置。   When it is desired to recirculate high-temperature exhaust gas to the intake system during low-load operation, an exhaust passage on the exhaust upstream side from the exhaust passage upstream of the EGR passage connection portion passes through the EGR passage connection portion and the exhaust passage downstream of the EGR passage connection portion. The first direction control means is set so that only the flow of the exhaust gas flowing to the exhaust is allowed, and the exhaust gas flowing from the exhaust passage upstream of the bypass passage upstream of the bypass passage upstream to the bypass passage through the bypass passage connecting portion The second direction control means is set so that only the gas flow is allowed, the EGR valve is set to have a recirculation amount of the exhaust gas according to the operating state, and the waste gate valve is set to open. The exhaust device for an internal combustion engine according to any one of claims 1 to 3.
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