JP2005330842A - Internal combustion engine - Google Patents

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JP2005330842A
JP2005330842A JP2004148253A JP2004148253A JP2005330842A JP 2005330842 A JP2005330842 A JP 2005330842A JP 2004148253 A JP2004148253 A JP 2004148253A JP 2004148253 A JP2004148253 A JP 2004148253A JP 2005330842 A JP2005330842 A JP 2005330842A
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combustion chamber
intake
exhaust
port
intake port
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JP4315053B2 (en
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Yasushi Katsurayama
裕史 葛山
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Toyota Industries Corp
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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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  • Control Of Throttle Valves Provided In The Intake System Or In The Exhaust System (AREA)
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Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal combustion engine capable of stably performing combustion in a wide load range without being limited to premixed compression self-ignition combustion and spark-ignition combustion, when using internal EGR for making part of exhaust gas flow back from an exhaust port to inside of a combustion chamber. <P>SOLUTION: The second exhaust port 22 for making part of exhaust gas flow back to a central part of the combustion chamber 16 in the middle of an intake stroke is provided as a helical port. The internal combustion engine is provided with a first intake port 19 for supplying intake air to the combustion chamber 16 so as to make the intake air flow in the same direction as that of a flow of exhaust gas flowing from the exhaust suction port 22 into inside of the combustion chamber 16, and with a second intake port 20 for supplying intake air to the combustion chamber 16 so as to make the intake air flow in the direction reverse to that of a flow of intake air flowing from the first intake port 19 into inside of the combustion chamber 16. Supply amount of intake air supplied from the both intake ports 19, 20 to the combustion chamber 16 is controlled by a flow regulating valve 44. When the internal EGR is performed, intake air is supplied at least from the second intake port 20. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、内燃機関に係り、詳しくは吸気行程の途中において排気ガスの一部を排気ポートから燃焼室内に逆流させる内部ＥＧＲが可能に構成された内燃機関に関する。   The present invention relates to an internal combustion engine, and more particularly, to an internal combustion engine configured to be capable of internal EGR in which a part of exhaust gas flows backward from an exhaust port into a combustion chamber during an intake stroke.

従来の内燃機関は大きく分けると、ＳＩ（Spark Ignition）エンジンと、ディーゼルエンジンの２つである。しかし、ＳＩエンジンはリーン化で熱効率向上が可能だが、火炎伝播可能な当量比に限界があるため、スロットルによる空気量の調整が必要で熱効率はディーゼルエンジンより劣る。また、ディーゼルエンジンは熱効率は良いが十分な混合がなされないため、局所高温燃焼によりＮＯｘが発生し易く、局所リッチで煤が発生し易い。   Conventional internal combustion engines can be broadly divided into two types: SI (Spark Ignition) engines and diesel engines. However, the SI engine can improve heat efficiency by leaning, but there is a limit to the equivalence ratio that allows flame propagation, so adjustment of the air amount by the throttle is necessary and the heat efficiency is inferior to that of the diesel engine. Diesel engines have good thermal efficiency but are not sufficiently mixed. Therefore, NOx is likely to be generated by local high-temperature combustion, and soot is likely to be locally rich.

これらのエンジンと比較して、予混合圧縮自着火機関は予混合するため、局所の高温やリッチが発生する可能性が小さく、低ＮＯｘで煤の発生はほとんど無い。また、化学変化による着火のため、当量比に対する依存度がＳＩエンジンよりも少ないため、大幅なリーン化が可能でありディーゼルエンジン並の熱効率を得ることができる。これらの長所を備えた予混合圧縮自着火機関が注目されている。予混合圧縮自着火燃焼は、熱が十分すぎると急激な燃焼となり、逆に、熱が足りないと失火してしまうため、現行のエンジンと比較して失火やノック・過早着火等が発生し易くなり、運転可能範囲が狭くなり易いという問題がある。   Compared to these engines, the premixed compression auto-ignition engine premixes, so there is less possibility of local high temperature and richness, and low NOx and almost no soot generation. In addition, because of the ignition due to chemical change, the dependence on the equivalence ratio is less than that of the SI engine, so that a significant leaning is possible and the thermal efficiency equivalent to that of a diesel engine can be obtained. A premixed compression auto-ignition engine having these advantages has attracted attention. In premixed compression auto-ignition combustion, if the heat is too high, it becomes abrupt combustion, and conversely, if there is not enough heat, it will misfire, causing misfire, knocking, pre-ignition, etc. compared to the current engine. There is a problem that the operating range is easily narrowed.

ノッキング等の異常燃焼を抑制する予混合圧縮自着火燃焼を行わせるため、気筒内に不均一な分布状態を生ぜしめるようにした予混合圧縮自着火機関が提案されている（特許文献１参照。）。そして、気筒内に不均一な分布状態を生ぜしめる方法として、気筒内の燃料分布を不均一な状態とすること、環流ガスが気筒内で不均一な分布状態となるようにすること等が提案されている。   In order to perform premixed compression autoignition combustion that suppresses abnormal combustion such as knocking, a premixed compression autoignition engine is proposed in which a non-uniform distribution state is generated in the cylinder (see Patent Document 1). ). Then, as a method for generating a non-uniform distribution state in the cylinder, it is proposed to make the fuel distribution in the cylinder non-uniform and to make the circulating gas non-uniform distribution in the cylinder. Has been.

また、ガソリンエンジンにおいて安定した圧縮自着火燃焼を行わせるために、排気ポートから排気ガスを燃焼室内に逆流させるとともに、その逆流排気ガスを燃焼室の外周に沿って流入させることが提案されている（特許文献２参照。）。具体的には、図１０に示すように、燃焼室６１に連通する第１吸気ポート６２及び第２吸気ポート６３と、燃焼室６１に連通する第１排気ポート６４及び第２排気ポート６５とを備えている。各ポートの開口部６２ａ，６３ａ，６４ａ，６５ａは、それぞれ図示しない弁により開閉されるようになっている。第１吸気ポート６２には燃料噴射弁６６が設けられ、第２吸気ポート６３には開閉弁６７が設けられている。燃焼室６１の中心と対応する位置に点火プラグ６８が設けられている。   Further, in order to perform stable compression auto-ignition combustion in a gasoline engine, it has been proposed to cause exhaust gas to flow back into the combustion chamber from the exhaust port and to flow back flow exhaust gas along the outer periphery of the combustion chamber. (See Patent Document 2). Specifically, as shown in FIG. 10, a first intake port 62 and a second intake port 63 that communicate with the combustion chamber 61, and a first exhaust port 64 and a second exhaust port 65 that communicate with the combustion chamber 61 are provided. I have. The openings 62a, 63a, 64a, 65a of each port are opened and closed by valves (not shown). The first intake port 62 is provided with a fuel injection valve 66, and the second intake port 63 is provided with an on-off valve 67. A spark plug 68 is provided at a position corresponding to the center of the combustion chamber 61.

第２排気ポート６５は、第１排気ポート６４と同様に排気行程において既燃焼ガスを排出するが、吸気行程の途中において一時排気ガスが燃焼室６１に逆流するように弁が開閉制御される。第２排気ポート６５は逆流排気ガスが燃焼室６１の外周方向に沿って流入するように、かつ第１吸気ポート６２から流入する燃料が燃焼室６１の中心部に向かって流入する邪魔にならないように設けられている。そして、燃焼室６１の外周部領域に逆流排気（内部ＥＧＲ）が主として分布し、燃焼室６１の中心部領域に燃料と空気との混合気が分布する状態になっている。
特開２００２−２４２７２７号公報（明細書の段落［０００８］〜［００１１］、図１） 特開平１１−２６４３１９号公報（明細書の段落［００１３］〜［００１５］、図２） Similarly to the first exhaust port 64, the second exhaust port 65 discharges the already burned gas during the exhaust stroke, but the valve is controlled to open and close so that the temporary exhaust gas flows backward to the combustion chamber 61 during the intake stroke. The second exhaust port 65 prevents backflow exhaust gas from flowing in along the outer circumferential direction of the combustion chamber 61, and does not obstruct the fuel flowing in from the first intake port 62 from flowing toward the center of the combustion chamber 61. Is provided. Then, backflow exhaust (internal EGR) is mainly distributed in the outer peripheral region of the combustion chamber 61, and a mixture of fuel and air is distributed in the central region of the combustion chamber 61.
JP 2002-242727 A (paragraphs [0008] to [0011] in FIG. 1, FIG. 1) JP 11-264319 A (paragraphs [0013] to [0015] in FIG. 2, FIG. 2)

予混合圧縮自着火燃焼において、気筒内の温度ムラや混合気ムラは確かに燃焼状態に影響を与えるが、ムラの状態によってはノッキングから一気に失火する可能性もある。特許文献１には、具体的な気筒内混合気の状態に関して記載がない。一方、特許文献２に記載されたように、燃焼室の中心部に混合気を集め、燃焼室の壁面に沿うように内部ＥＧＲの逆流排気ガス（以下、単に内部ＥＧＲガスと言う。）を流入させる方法においては、予混合圧縮自着火燃焼を安定して行うことができる。ところで、内部ＥＧＲガスは既燃焼ガスのため燃えないので、内部ＥＧＲガス量はできるだけ少なくしたい。しかし、内部ＥＧＲガスを燃焼室の壁面に沿うように流入させる特許文献２の方法では、燃焼室の壁面は冷却水等の冷却効果で中心部より低くなっているため、内部ＥＧＲガスの温度が下がり易くなり、低負荷での運転時に燃焼が不安定になる虞がある。また、そのため、内部ＥＧＲガス量を少なくするのが難しく、その分、燃焼室に供給する混合気の量を多くすることができない。従って、内部ＥＧＲガスを燃焼室の壁面側に集める方法では、広い負荷範囲において安定して予混合圧縮自着火燃焼をおこなうのは難しい。   In the premixed compression self-ignition combustion, the temperature unevenness and the air-fuel mixture unevenness in the cylinder certainly affect the combustion state, but depending on the state of the unevenness, there is a possibility of misfire from knocking. Patent Document 1 does not describe a specific state of the in-cylinder mixture. On the other hand, as described in Patent Document 2, the air-fuel mixture is collected at the center of the combustion chamber, and the backflow exhaust gas of the internal EGR (hereinafter simply referred to as internal EGR gas) flows along the wall surface of the combustion chamber. In this method, premixed compression auto-ignition combustion can be performed stably. By the way, since the internal EGR gas does not burn because it is already burned gas, it is desired to reduce the amount of internal EGR gas as much as possible. However, in the method of Patent Document 2 in which the internal EGR gas is caused to flow along the wall surface of the combustion chamber, the wall surface of the combustion chamber is lower than the center due to the cooling effect of cooling water or the like. It tends to fall, and there is a possibility that combustion becomes unstable during operation at a low load. For this reason, it is difficult to reduce the amount of internal EGR gas, and accordingly, the amount of air-fuel mixture supplied to the combustion chamber cannot be increased. Therefore, in the method of collecting the internal EGR gas on the wall surface side of the combustion chamber, it is difficult to stably perform premixed compression auto-ignition combustion over a wide load range.

また、火花点火燃焼においても排気ガスの一部を排気ポートから燃焼室内に逆流させる前記内部ＥＧＲを使用したい場合があるが、温度が高い内部ＥＧＲガスを燃焼室の特定部分に集めると、ホットスポットでノッキングが発生し易くなる。特許文献２の構成では、内部ＥＧＲガスと吸気との混合を促進することは配慮されておらず、特許文献２の構成を火花点火燃焼に適用した場合、安定した燃焼は難しい。   Further, in spark ignition combustion, there is a case where it is desired to use the internal EGR that causes a part of the exhaust gas to flow backward from the exhaust port into the combustion chamber. However, if the internal EGR gas having a high temperature is collected in a specific portion of the combustion chamber, Therefore, knocking is likely to occur. In the configuration of Patent Document 2, consideration is not given to promoting the mixing of the internal EGR gas and the intake air, and stable combustion is difficult when the configuration of Patent Document 2 is applied to spark ignition combustion.

本発明は、前記従来の問題に鑑みてなされたものであって、その目的は、排気ガスの一部を排気ポートから燃焼室内に逆流させる前記内部ＥＧＲを使用する際に、予混合圧縮自着火燃焼及び火花点火燃焼に限らず、広い負荷範囲で安定して燃焼を行うことができる内燃機関を提供することにある。   The present invention has been made in view of the above-described conventional problems, and its object is to use premixed compression auto-ignition when using the internal EGR that causes a part of the exhaust gas to flow backward from the exhaust port into the combustion chamber. In addition to combustion and spark ignition combustion, an object of the present invention is to provide an internal combustion engine that can stably perform combustion in a wide load range.

前記の目的を達成するため、請求項１に記載の発明は、吸気行程の途中において排気ガスの一部を排気ポートから燃焼室内に逆流させる内部ＥＧＲを行う内部ＥＧＲ手段と、前記内部ＥＧＲ手段を構成し、排気ガスの一部を燃焼室内に逆流させる排気吸入ポートとを備えている。また、前記排気吸入ポートから前記燃焼室内に流入する排気ガスの流れと同方向の流れとなるように吸気を前記燃焼室に供給する第１吸気ポートと、前記排気吸入ポートから前記燃焼室内に流入する排気ガスとの混合を促進するように吸気を前記燃焼室に供給する第２吸気ポートと、前記第１吸気ポート及び第２吸気ポートから前記燃焼室へ供給される吸気の供給量を制御可能な流量調整弁とを備えている。また、機関の運転条件に基づいて前記流量調整弁を制御し、内部ＥＧＲガスと吸気との混合を促進したい場合に前記第２吸気ポートからのみ吸気を供給するように前記流量調整弁を制御する制御手段を備えている。ここで、「吸気」とは、燃焼室に接続された吸気ポートから燃焼室に供給される気体を意味し、空気等の含有酸素ガスに限らず、それらと燃料ガスとの混合気をも含む。   In order to achieve the above object, according to the first aspect of the present invention, there is provided an internal EGR means for performing an internal EGR for causing a part of exhaust gas to flow backward from an exhaust port into the combustion chamber in the middle of an intake stroke, and the internal EGR means. And an exhaust suction port for allowing a part of the exhaust gas to flow back into the combustion chamber. A first intake port for supplying intake air to the combustion chamber so as to flow in the same direction as an exhaust gas flowing into the combustion chamber from the exhaust intake port; and an inflow into the combustion chamber from the exhaust intake port A second intake port for supplying intake air to the combustion chamber so as to promote mixing with exhaust gas to be controlled, and a supply amount of intake air supplied from the first intake port and the second intake port to the combustion chamber can be controlled And an appropriate flow control valve. Further, the flow rate adjusting valve is controlled based on engine operating conditions, and the flow rate adjusting valve is controlled so that intake air is supplied only from the second intake port when it is desired to promote mixing of internal EGR gas and intake air. Control means are provided. Here, “intake” refers to gas supplied to the combustion chamber from an intake port connected to the combustion chamber, and includes not only oxygen gas such as air but also a mixture of these and fuel gas. .

従って、この発明では、燃焼室への吸気の供給は、第１吸気ポート及び第２吸気ポートから供給可能であり、内部ＥＧＲを行う際には、第２吸気ポートからのみ吸気が供給されるように流量調整弁が制御される。従って、排気吸入ポートから燃焼室に流入する排気ガス、即ち内部ＥＧＲガスと吸気との混合が促進され、予混合圧縮自着火燃焼及び火花点火燃焼に限らず、安定して燃焼を行うことができる。   Accordingly, in the present invention, the intake air can be supplied to the combustion chamber from the first intake port and the second intake port, and when performing the internal EGR, the intake air is supplied only from the second intake port. The flow rate adjusting valve is controlled. Therefore, the mixing of the exhaust gas flowing into the combustion chamber from the exhaust intake port, that is, the internal EGR gas and the intake air is promoted, and the combustion can be stably performed without being limited to the premixed compression self-ignition combustion and the spark ignition combustion. .

請求項２に記載の発明は、請求項１に記載の発明において、内燃機関は、燃料と酸素含有ガスとの混合気を燃焼室においてピストンで圧縮して自着火燃焼させ、前記ピストンの往復運動を出力軸の回転運動とする予混合圧縮自着火機関である。前記排気吸入ポートは前記燃焼室に流入する排気ガスが前記燃焼室の中心部に向かうように設けられている。また、前記第１吸気ポートは前記燃焼室に供給される吸気が前記燃焼室の内周面に沿う流れとなるように設けられ、前記第２吸気ポートは前記燃焼室に供給される吸気が前記燃焼室の内周面に沿う流れで前記第１吸気ポートから供給される吸気の流れと逆方向となるように設けられている。   According to a second aspect of the present invention, in the first aspect of the present invention, the internal combustion engine compresses a mixture of fuel and oxygen-containing gas with a piston in a combustion chamber and performs self-ignition combustion, and the piston reciprocates. Is a premixed compression auto-ignition engine with a rotary motion of the output shaft. The exhaust suction port is provided so that exhaust gas flowing into the combustion chamber is directed toward the center of the combustion chamber. The first intake port is provided so that the intake air supplied to the combustion chamber flows along the inner peripheral surface of the combustion chamber, and the second intake port receives the intake air supplied to the combustion chamber. A flow along the inner peripheral surface of the combustion chamber is provided so as to be opposite to the flow of the intake air supplied from the first intake port.

この発明では、排気吸入ポートから燃焼室内に逆流される内部ＥＧＲガスは燃焼室の中心部に集まり、第１吸気ポート及び第２吸気ポートから燃焼室に供給される吸気は燃焼室の内周面沿う流れとなり、内部ＥＧＲガスと混合気とは内部ＥＧＲガスが内側の層状になる。そして、圧縮行程で圧縮されると、内部ＥＧＲガスと混合気との界面から予混合圧縮自着火燃焼が開始される。内部ＥＧＲガスが中心部に集まるため、内部ＥＧＲガスが少量でも温度を高くすることができ、高負荷においても安定した予混合圧縮自着火燃焼が可能になる。   In this invention, the internal EGR gas that flows back from the exhaust intake port into the combustion chamber gathers in the center of the combustion chamber, and the intake air supplied from the first intake port and the second intake port to the combustion chamber is the inner peripheral surface of the combustion chamber. The internal EGR gas and the air-fuel mixture are layered on the inner EGR gas. When the compression is performed in the compression stroke, premixed compression self-ignition combustion is started from the interface between the internal EGR gas and the air-fuel mixture. Since the internal EGR gas gathers in the center, the temperature can be increased even with a small amount of the internal EGR gas, and stable premixed compression auto-ignition combustion is possible even at high loads.

請求項３に記載の発明は、請求項２に記載の発明において、前記燃焼室には点火装置が装備されるとともに、排気ポートは複数設けられ、一つの排気ポートが前記排気吸入ポートとなっている。前記制御手段は、内燃機関の運転条件に応じて、予混合圧縮自着火燃焼運転時において前記第１吸気ポートからのみ吸気を供給する状態と、予混合圧縮自着火燃焼運転時において前記第１吸気ポート及び第２吸気ポートの両方から吸気を供給する状態と、火花点火燃焼運転時において前記第２吸気ポートからのみ吸気を供給する状態とに前記流量調整弁を制御する。   The invention according to claim 3 is the invention according to claim 2, wherein the combustion chamber is equipped with an ignition device, a plurality of exhaust ports are provided, and one exhaust port serves as the exhaust intake port. Yes. The control means supplies the intake air only from the first intake port during the premixed compression autoignition combustion operation and the first intake air during the premixed compression autoignition combustion operation according to the operating conditions of the internal combustion engine. The flow rate adjusting valve is controlled to a state in which intake air is supplied from both the port and the second intake port and a state in which intake air is supplied only from the second intake port during the spark ignition combustion operation.

従って、この発明では、内部ＥＧＲを行う場合、第１吸気ポートからのみ吸気を供給する状態では内部ＥＧＲガスと吸気とは成層状が乱されずに圧縮され中央付近から着火が生じる。また、第１吸気ポート及び第２吸気ポートから吸気を供給する状態では、第２吸気ポートから供給される吸気は、内部ＥＧＲガスと逆方向の流れのため吸気と内部ＥＧＲガスとの混合が促進されるとともに、第１吸気ポートから供給される吸気と流れが逆方向のため吸気同士でも混合が促進され。その結果、ホットスポットが少なくなり、燃焼が緩慢になってノッキング等の異常燃焼が抑制される。また、火花点火燃焼時には、第２吸気ポートのみから吸気を供給することにより、吸気と内部ＥＧＲガスとの混合がより促進され、自着火を起こすホットスポットを無くしてノッキングの抑制が行われる。従って、広い負荷条件において安定した燃焼を行うことができる。   Therefore, in the present invention, when performing the internal EGR, the internal EGR gas and the intake air are compressed without being disturbed in the stratified state in a state where the intake air is supplied only from the first intake port, and ignition occurs from around the center. In addition, in a state in which intake air is supplied from the first intake port and the second intake port, the intake air supplied from the second intake port flows in the opposite direction to the internal EGR gas, so that mixing of the intake air and the internal EGR gas is promoted. In addition, since the intake air supplied from the first intake port and the flow are in the opposite direction, mixing is promoted even between the intake air. As a result, hot spots are reduced, combustion is slowed down, and abnormal combustion such as knocking is suppressed. Further, at the time of spark ignition combustion, by supplying intake air from only the second intake port, mixing of the intake air and the internal EGR gas is further promoted, and knocking is suppressed by eliminating hot spots that cause self-ignition. Therefore, stable combustion can be performed under a wide load condition.

請求項４に記載の発明は、請求項１〜請求項３のいずれか一項に記載の発明において、前記燃焼室に排気ポートは２個設けられ、一方の排気ポートが前記排気吸入ポートとなり、該排気吸入ポートには流量調整手段が設けられている。従って、この発明では、排気吸入ポートから排気ガスを逆流させて内部ＥＧＲを行う場合、排気吸入ポートを開閉する排気弁の開閉時期は一定でも、流量調整手段で流量を調整することにより、燃焼状態の制御が容易になる。   The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein two exhaust ports are provided in the combustion chamber, and one exhaust port serves as the exhaust intake port, The exhaust suction port is provided with a flow rate adjusting means. Therefore, according to the present invention, when the internal EGR is performed by causing the exhaust gas to flow backward from the exhaust intake port, the combustion state is adjusted by adjusting the flow rate with the flow rate adjusting means even if the open / close timing of the exhaust valve that opens and closes the exhaust intake port is constant. It becomes easy to control.

本発明によれば、排気ガスの一部を排気ポートから燃焼室内に逆流させる前記内部ＥＧＲを使用する際に、予混合圧縮自着火燃焼及び火花点火燃焼に限らず、安定して燃焼を行うことができる。   According to the present invention, when using the internal EGR that causes a part of the exhaust gas to flow backward from the exhaust port into the combustion chamber, not only premixed compression self-ignition combustion and spark ignition combustion, but also stable combustion is performed. Can do.

以下、本発明を予混合圧縮自着火機関に具体化した一実施形態を図１〜図６に従って説明する。図１は予混合圧縮自着火機関の燃焼室、吸気ポート、排気ポートの関係を示す模式平面図であり、図２は予混合圧縮自着火機関の概略構成図である。   Hereinafter, an embodiment in which the present invention is embodied in a premixed compression self-ignition engine will be described with reference to FIGS. FIG. 1 is a schematic plan view showing the relationship between a combustion chamber, an intake port, and an exhaust port of a premixed compression self-ignition engine, and FIG. 2 is a schematic configuration diagram of the premixed compression autoignition engine.

図２に示すように、予混合圧縮自着火機関１０（以下、単に機関と称す場合もある。）は、機関本体１１と、予混合圧縮自着火機関１０を電子制御する制御装置１２とを備えている。   As shown in FIG. 2, the premixed compression autoignition engine 10 (hereinafter sometimes simply referred to as an engine) includes an engine body 11 and a control device 12 that electronically controls the premixed compression autoignition engine 10. ing.

機関本体１１は、複数のシリンダ１３ａ（図では１個のみ図示）が形成されたシリンダブロック１３と、シリンダヘッド１４とを備えている。各シリンダ１３ａ内にはピストン１５が往復動可能に設けられている。ピストン１５と、シリンダ１３ａ及びシリンダヘッド１４によって燃焼室１６が形成されている。ピストン１５は燃焼室１６での吸気・圧縮後の爆発燃焼から得られる推進力によってシリンダ１３ａ内を往復運動し、ピストン１５の往復運動がコンロッド１７を介して出力軸としてのクランクシャフト１８の回転運動に変換されて出力が得られる。機関本体１１は４サイクル内燃機関である。   The engine body 11 includes a cylinder block 13 in which a plurality of cylinders 13a (only one is shown in the figure) is formed, and a cylinder head 14. A piston 15 is provided in each cylinder 13a so as to be able to reciprocate. A combustion chamber 16 is formed by the piston 15, the cylinder 13 a and the cylinder head 14. The piston 15 reciprocates in the cylinder 13 a by the propulsive force obtained from the explosion combustion after intake and compression in the combustion chamber 16, and the reciprocating motion of the piston 15 rotates the crankshaft 18 as the output shaft via the connecting rod 17. To get the output. The engine body 11 is a four-cycle internal combustion engine.

シリンダヘッド１４には第１吸気ポート１９及び第２吸気ポート２０と、第１の排気ポート２１と、排気吸入ポートとしての第２の排気ポート２２とが設けられている。第２の排気ポート２２はヘリカルポートとして形成されており、第２の排気ポート２２から燃焼室１６へ逆流する排気ガスが燃焼室１６の中心部に流入するように設けられている。第２の排気ポート２２は排気ガスが渦流となって燃焼室１６に流入し易い形状に形成されているため、排気行程における排気に適した形状ではない。排気行程における排気を円滑に行うため、第１の排気ポート２１は第２の排気ポート２２より内径が大きく形成されている。   The cylinder head 14 is provided with a first intake port 19 and a second intake port 20, a first exhaust port 21, and a second exhaust port 22 as an exhaust intake port. The second exhaust port 22 is formed as a helical port, and is provided so that the exhaust gas flowing backward from the second exhaust port 22 to the combustion chamber 16 flows into the center of the combustion chamber 16. Since the second exhaust port 22 is formed in a shape that allows the exhaust gas to easily flow into the combustion chamber 16 as a vortex, the shape is not suitable for exhaust in the exhaust stroke. The first exhaust port 21 has a larger inner diameter than the second exhaust port 22 in order to smoothly exhaust in the exhaust stroke.

第１吸気ポート１９は、吸気（新気）が、第２の排気ポート２２から燃焼室１６内に逆流する排気ガスの流れと同方向で燃焼室１６の周壁面に沿う流れとなって供給されるように形成されている。具体的には燃焼室１６の内壁面に対する接線方向に延びるように形成されている。第２吸気ポート２０は、吸気（新気）が、第１吸気ポート１９から燃焼室１６内に供給される吸気と逆方向で燃焼室１６の周壁面に沿う流れとなるように形成されている。   The first intake port 19 is supplied with the intake air (fresh air) as a flow along the peripheral wall surface of the combustion chamber 16 in the same direction as the flow of the exhaust gas flowing backward from the second exhaust port 22 into the combustion chamber 16. It is formed so that. Specifically, it is formed to extend in a tangential direction with respect to the inner wall surface of the combustion chamber 16. The second intake port 20 is formed so that the intake air (fresh air) flows along the peripheral wall surface of the combustion chamber 16 in the opposite direction to the intake air supplied from the first intake port 19 into the combustion chamber 16. .

各吸気ポート１９，２０には燃焼室１６に臨む開口部をそれぞれ開閉する吸気弁２３，２４が設けられ、各排気ポート２１，２２には燃焼室１６に臨む開口部をそれぞれ開閉する排気弁２５，２６が設けられている。両吸気弁２３，２４は、可変動弁機構２７により同時に開閉可能に構成されている。両排気弁２５，２６は、可変動弁機構２８により、排気行程においては同時に開閉可能に、かつ吸気行程においては第２の排気ポート２２用の排気弁２６のみが所定のタイミングで開閉可能に構成されている。可変動弁機構２７，２８は、カムシャフト２９，３０を使用してカム３１，３２により吸気弁２３，２４あるいは排気弁２５，２６を開閉作動させる公知のバルブタイミング可変機構が使用されている。排気弁２６用のカム３２には２段カムが使用され、一つのカムで排気行程における排気弁２６の開閉と、吸気行程における排気弁２６の開閉とが可能に構成されている。   Each intake port 19, 20 is provided with an intake valve 23, 24 for opening and closing an opening facing the combustion chamber 16, and each exhaust port 21, 22 is an exhaust valve 25 for opening and closing an opening facing the combustion chamber 16. , 26 are provided. Both intake valves 23 and 24 are configured to be opened and closed simultaneously by a variable valve mechanism 27. Both exhaust valves 25 and 26 can be opened and closed simultaneously by the variable valve mechanism 28 in the exhaust stroke, and only the exhaust valve 26 for the second exhaust port 22 can be opened and closed at a predetermined timing in the intake stroke. Has been. As the variable valve mechanisms 27 and 28, known valve timing variable mechanisms that use the camshafts 29 and 30 to open and close the intake valves 23 and 24 or the exhaust valves 25 and 26 by the cams 31 and 32 are used. A two-stage cam is used as the cam 32 for the exhaust valve 26, and it is possible to open and close the exhaust valve 26 in the exhaust stroke and open and close the exhaust valve 26 in the intake stroke with one cam.

また、シリンダヘッド１４には、点火装置としての点火プラグ３３がその点火部を燃焼室１６に露出させた状態で設けられている。
シリンダヘッド１４には下流側で分岐して両吸気ポート１９，２０に繋がる吸気通路３４と、上流側で分岐して両排気ポート２１，２２に繋がる排気通路３５とがそれぞれ接続されている。吸気通路３４には分岐部より上流に燃料噴射ノズル３６が設けられ、燃料噴射ノズル３６は管路３７を介して図示しない燃料タンクに接続されている。管路３７の途中には燃料供給量を制御する電磁制御弁３８が設けられている。この実施形態では燃料として天然ガスが使用されている。また、吸気通路３４の燃料噴射ノズル３６より上流にはスロットルバルブ３９及びエアクリーナ４０が設けられている。スロットルバルブ３９はスロットルモータ（電動モータ）４１によって作動される電動式であり、スロットルバルブ３９を開度調整することにより、燃焼室１６内に供給される酸素含有ガスとしての吸入空気の流量が調整される。吸気通路３４には燃料噴射ノズル３６より上流側に、吸気通路３４内の温度を検出する温度センサ４２と、吸気流量を検出するエアフローメータ４３とが設けられている。 Further, the cylinder head 14 is provided with a spark plug 33 as an ignition device in a state where the ignition portion is exposed to the combustion chamber 16.
The cylinder head 14 is connected to an intake passage 34 that branches on the downstream side and connects to both intake ports 19 and 20, and an exhaust passage 35 that branches on the upstream side and connects to both exhaust ports 21 and 22. A fuel injection nozzle 36 is provided in the intake passage 34 upstream of the branch portion, and the fuel injection nozzle 36 is connected to a fuel tank (not shown) via a pipe 37. An electromagnetic control valve 38 for controlling the fuel supply amount is provided in the middle of the pipe line 37. In this embodiment, natural gas is used as the fuel. A throttle valve 39 and an air cleaner 40 are provided upstream of the fuel injection nozzle 36 in the intake passage 34. The throttle valve 39 is an electric type operated by a throttle motor (electric motor) 41, and the flow rate of intake air as an oxygen-containing gas supplied into the combustion chamber 16 is adjusted by adjusting the opening of the throttle valve 39. Is done. In the intake passage 34, a temperature sensor 42 that detects the temperature in the intake passage 34 and an air flow meter 43 that detects the intake flow rate are provided upstream of the fuel injection nozzle 36.

吸気通路３４の分岐部には、第１吸気ポート１９及び第２吸気ポート２０から燃焼室１６へ供給される吸気の供給量を制御可能な流量調整弁４４が設けられている。流量調整弁４４は、第１吸気ポート１９及び第２吸気ポート２０への吸気の流量が流量調整弁４４より上流における吸気通路３４内の吸気の流量の０〜１００％の範囲でそれぞれ調整可能になっている。即ち、流量調整弁４４は、第１吸気ポート１９からのみ吸気を供給する状態と、第１吸気ポート１９及び第２吸気ポート２０の両方から吸気を供給する状態と、第２吸気ポートからのみ吸気を供給する状態とに流量を調整可能になっている。流量調整弁４４として、例えばスプール弁を使用できる。   A flow rate adjusting valve 44 capable of controlling the amount of intake air supplied from the first intake port 19 and the second intake port 20 to the combustion chamber 16 is provided at a branch portion of the intake passage 34. The flow rate adjustment valve 44 can be adjusted so that the flow rate of intake air to the first intake port 19 and the second intake port 20 ranges from 0 to 100% of the flow rate of intake air in the intake passage 34 upstream of the flow rate adjustment valve 44. It has become. That is, the flow rate adjustment valve 44 is in a state in which intake air is supplied only from the first intake port 19, a state in which intake air is supplied from both the first intake port 19 and the second intake port 20, and an intake air only from the second intake port. The flow rate can be adjusted to the state where the gas is supplied. As the flow rate adjusting valve 44, for example, a spool valve can be used.

予混合圧縮自着火機関１０の運転を制御する制御装置１２は、出力設定手段４５により設定された負荷及び回転速度の要求を満たした状態で機関１０が運転されるように、可変動弁機構２７，２８、電磁制御弁３８、スロットルモータ４１、点火プラグ３３及び流量調整弁４４を制御する。   The control device 12 that controls the operation of the premixed compression self-ignition engine 10 is configured to operate the variable valve mechanism 27 so that the engine 10 is operated in a state where the load and rotation speed requirements set by the output setting means 45 are satisfied. , 28, the electromagnetic control valve 38, the throttle motor 41, the spark plug 33 and the flow rate adjusting valve 44 are controlled.

制御装置１２はマイクロコンピュータ（以下「マイコン」と称す）４６を内蔵する。マイコン４６は記憶装置としてのメモリ（ＲＯＭおよびＲＡＭ）４７を備える。温度センサ４２、エアフローメータ４３、機関本体１１における水温を検出する水温センサ４８、機関本体１１の回転速度、即ちクランクシャフト１８の回転速度を検出する回転速度センサ４９、出力設定手段４５は、制御装置１２の入力側（入力インタフェイス）にそれぞれ電気的に接続されている。可変動弁機構２７，２８、電磁制御弁３８、点火プラグ３３、スロットルモータ４１及び流量調整弁４４は、制御装置１２の出力側（出力インタフェイス）にそれぞれ電気的に接続されている。   The control device 12 incorporates a microcomputer (hereinafter referred to as “microcomputer”) 46. The microcomputer 46 includes a memory (ROM and RAM) 47 as a storage device. The temperature sensor 42, the air flow meter 43, the water temperature sensor 48 for detecting the water temperature in the engine body 11, the rotation speed sensor 49 for detecting the rotation speed of the engine body 11, that is, the rotation speed of the crankshaft 18, and the output setting means 45 are a control device. The twelve input sides (input interfaces) are electrically connected to each other. The variable valve mechanisms 27 and 28, the electromagnetic control valve 38, the spark plug 33, the throttle motor 41, and the flow rate adjusting valve 44 are electrically connected to the output side (output interface) of the control device 12, respectively.

制御装置１２は、各センサ類から出力される検出信号に基づいて予混合圧縮自着火機関１０の運転状態を判断し、所定の運転状態となるように可変動弁機構２７，２８、電磁制御弁３８、点火プラグ３３、スロットルモータ４１及び流量調整弁４４を制御する。制御装置１２は、エアフローメータ４３の検出信号及び電磁制御弁３８の開度に基づいて空燃比を演算する。   The control device 12 determines the operating state of the premixed compression auto-ignition engine 10 based on the detection signals output from the sensors, and the variable valve mechanisms 27 and 28, the electromagnetic control valve so as to be in a predetermined operating state. 38, the spark plug 33, the throttle motor 41 and the flow rate adjusting valve 44 are controlled. The control device 12 calculates the air-fuel ratio based on the detection signal of the air flow meter 43 and the opening degree of the electromagnetic control valve 38.

メモリ４７には、温度センサ４２、エアフローメータ４３、水温センサ４８及び回転速度センサ４９の検出信号から把握される運転状態に基づいて、予混合圧縮自着火機関１０の制御のために指令すべき各種指令値（制御値）の決定に用いられるマップ、式等が記憶されている。前記マップ、式等には、例えば燃料噴射量、スロットル開度、第１吸気ポート１９及び第２吸気ポート２０からの吸気供給量、点火時期等を決めるマップ、式等が含まれる。   In the memory 47, various commands to be commanded for controlling the premixed compression self-ignition engine 10 based on the operation state grasped from the detection signals of the temperature sensor 42, the air flow meter 43, the water temperature sensor 48 and the rotation speed sensor 49. A map, a formula, and the like used for determining the command value (control value) are stored. The maps, formulas, and the like include maps, formulas, and the like that determine, for example, the fuel injection amount, the throttle opening, the intake air supply amount from the first intake port 19 and the second intake port 20, the ignition timing, and the like.

メモリ４７には、予混合圧縮自着火燃焼運転用のマップが記憶されている。前記マップには図３に示すように、予混合圧縮自着火燃焼（ＨＣＣＩ）可能な範囲が、負荷とクランクシャフト１８の回転速度との関係として、即ち負荷と機関の回転速度との関係として表されているマップＭ１がある。また、安定な予混合圧縮自着火燃焼が可能な範囲での機関の回転速度及び負荷に対する空燃比のマップがある。また、第１及び第２吸気ポート１９，２０からどのように吸気を供給するか、即ち流量調整弁４４の適正調整状態を負荷及び機関の回転速度との関係で示すマップもある。また、メモリ４７には予混合圧縮自着火燃焼運転用のマップの他に、火花点火燃焼運転用のマップ（図示せず）も記憶されている。これらのマップは予め試験に基づいて作成される。   The memory 47 stores a map for premixed compression auto-ignition combustion operation. As shown in FIG. 3, the map shows the premixed compression auto-ignition combustion (HCCI) possible range as the relationship between the load and the rotational speed of the crankshaft 18, that is, as the relationship between the load and the rotational speed of the engine. There is a map M1. Further, there is a map of the air-fuel ratio with respect to the engine speed and load in a range where stable premixed compression auto-ignition combustion is possible. There is also a map showing how the intake air is supplied from the first and second intake ports 19 and 20, that is, the proper adjustment state of the flow rate adjusting valve 44 in relation to the load and the rotational speed of the engine. In addition to the premixed compression auto-ignition combustion operation map, the memory 47 also stores a spark ignition combustion operation map (not shown). These maps are created in advance based on tests.

制御装置１２は、前記マップＭ１に基づいて要求負荷及び回転速度に対応して予混合圧縮自着火燃焼運転が可能か否かを判断し、予混合圧縮自着火燃焼運転が可能な場合は予混合圧縮自着火燃焼運転で、不能な場合は火花点火燃焼運転で、要求負荷及び回転速度に対応するように制御を行う。制御装置１２は、要求負荷及び回転速度に対応する予混合圧縮自着火機関１０の運転条件に基づいて吸気をどのような状態で燃焼室１６へ供給するか、即ち第１吸気ポート１９のみから、第２吸気ポート２０のみからあるいは第１吸気ポート１９及び第２吸気ポート２０の両方から供給するかを判断する。そして、判断結果に基づいて流量調整弁４４を制御する。   Based on the map M1, the control device 12 determines whether or not the premixed compression autoignition combustion operation is possible according to the required load and the rotational speed. In compression auto-ignition combustion operation, if impossible, spark ignition combustion operation is performed to control the required load and rotation speed. The control device 12 supplies the intake air to the combustion chamber 16 based on the operating conditions of the premixed compression auto-ignition engine 10 corresponding to the required load and the rotational speed, that is, only from the first intake port 19. It is determined whether to supply from the second intake port 20 alone or from both the first intake port 19 and the second intake port 20. Then, the flow rate adjusting valve 44 is controlled based on the determination result.

次に前記のように構成された装置の作用を説明する。
制御装置１２は、予混合圧縮自着火機関１０の運転に際して、予混合圧縮自着火燃焼運転を優先的に行うように運転を行うが、要求負荷及び機関回転速度が予混合圧縮自着火燃焼が可能な範囲にない場合は、火花点火燃焼運転を行う。また、制御装置１２は、暖機完了までは火花点火燃焼運転を行う。 Next, the operation of the apparatus configured as described above will be described.
When the premixed compression autoignition engine 10 is operated, the control device 12 operates so as to preferentially perform the premixed compression autoignition combustion operation. However, the required load and the engine rotation speed are capable of premixed compression autoignition combustion. If not, perform spark ignition combustion operation. Further, the control device 12 performs the spark ignition combustion operation until the warm-up is completed.

制御装置１２は、水温センサ４８及び回転速度センサ４９等の検出信号から機関本体１１の運転状態を把握する。そして、暖機完了後、出力設定手段４５で設定された要求回転速度及び負荷を満たす状態で、予混合圧縮自着火燃焼運転が可能か否かをマップＭ１に基づいて判断し、その判断結果に従って予混合圧縮自着火燃焼運転あるいは火花点火燃焼運転を行うように、目標回転速度及び負荷を演算する。   The control device 12 grasps the operating state of the engine body 11 from detection signals from the water temperature sensor 48 and the rotation speed sensor 49. Then, after the warm-up is completed, it is determined based on the map M1 whether or not the premixed compression self-ignition combustion operation is possible in a state where the required rotational speed and load set by the output setting means 45 are satisfied, and according to the determination result The target rotational speed and the load are calculated so that the premixed compression self-ignition combustion operation or the spark ignition combustion operation is performed.

制御装置１２は、予混合圧縮自着火燃焼運転の場合は、その目標回転速度及び負荷に対応した適正な燃焼状態となる、空燃比及び吸気の供給状態となるように、電磁制御弁３８、スロットルモータ４１及び流量調整弁４４を制御する。また、火花点火燃焼運転の場合は、目標回転速度及び負荷に対応した適正な燃焼状態となる、空燃比、吸気の供給状態及び点火時期となるように、電磁制御弁３８、スロットルモータ４１、点火プラグ３３及び流量調整弁４４を制御する。   In the case of the premixed compression auto-ignition combustion operation, the controller 12 controls the electromagnetic control valve 38, the throttle so that the air-fuel ratio and the intake air supply state are brought into an appropriate combustion state corresponding to the target rotational speed and load. The motor 41 and the flow rate adjusting valve 44 are controlled. Further, in the case of spark ignition combustion operation, the electromagnetic control valve 38, the throttle motor 41, the ignition so that the air-fuel ratio, the intake air supply state, and the ignition timing are brought into an appropriate combustion state corresponding to the target rotational speed and load. The plug 33 and the flow rate adjusting valve 44 are controlled.

第２の排気ポート２２から燃焼室１６へ逆流する排気ガス（内部ＥＧＲガス）は、一定方向の渦流（矢印Ｖ１）となって燃焼室１６の中心部に流入する。そして、第１吸気ポート１９からのみ吸気（新気）が供給され、第２の排気ポート２２から排気ガスが逆流する場合、図４（ａ）に示すように、吸気は内部ＥＧＲガスと同方向の流れ（矢印Ｙ１）となって燃焼室１６の内周に沿うように供給される。従って、内部ＥＧＲガスが中央付近に集まり、その外側が新気となる成層状態となり、圧縮行程において筒内中央が高温となって、中央付近から自着火が起こり、安定して予混合圧縮自着火燃焼が行われる。第１吸気ポート１９からのみ吸気が供給されるのは、比較的低負荷のときである。   Exhaust gas (internal EGR gas) that flows backward from the second exhaust port 22 to the combustion chamber 16 flows into the central portion of the combustion chamber 16 as a vortex (arrow V1) in a certain direction. When the intake air (fresh air) is supplied only from the first intake port 19 and the exhaust gas flows backward from the second exhaust port 22, the intake air has the same direction as the internal EGR gas as shown in FIG. Is supplied along the inner periphery of the combustion chamber 16 (arrow Y1). Therefore, the internal EGR gas gathers in the vicinity of the center and the outside becomes fresh air, and the inside of the cylinder becomes high temperature in the compression stroke, self-ignition occurs from the vicinity of the center, and stable premixed compression auto-ignition occurs. Combustion takes place. The intake air is supplied only from the first intake port 19 when the load is relatively low.

また、第１吸気ポート１９及び第２吸気ポート２０の両者から吸気が供給され、第２の排気ポート２２から排気ガスが逆流する場合、図４（ｂ）に示すように、第２吸気ポート２０から供給される吸気は、第１吸気ポート１９から供給される吸気と逆方向の流れ（矢印Ｙ２）となる。第２吸気ポート２０から供給される吸気は、内部ＥＧＲガスとも流れの方向が逆のため、図４（ｂ）に二点鎖線で示す範囲において混合が促進される。また、第１吸気ポート１９から供給される吸気と、第２吸気ポート２０から供給される吸気とがぶつかり合うことによっても混合が促進される。その結果、圧縮行程において吸気及び内部ＥＧＲガスが高温になった際、ホットスポットが少なくなり、燃焼が緩慢になるため、予混合圧縮自着火燃焼が安定する。第１吸気ポート１９及び第２吸気ポート２０の両者から吸気が供給されるのは比較的高負荷のときである。   When intake air is supplied from both the first intake port 19 and the second intake port 20 and exhaust gas flows backward from the second exhaust port 22, as shown in FIG. 4B, the second intake port 20 From the first intake port 19 flows in the opposite direction (arrow Y2). The intake air supplied from the second intake port 20 is mixed in the range indicated by the two-dot chain line in FIG. 4B because the flow direction of the internal EGR gas is opposite to that of the internal EGR gas. Mixing is also promoted by the collision between the intake air supplied from the first intake port 19 and the intake air supplied from the second intake port 20. As a result, when the intake air and the internal EGR gas reach a high temperature during the compression stroke, the number of hot spots is reduced and the combustion becomes slow, so that the premixed compression self-ignition combustion is stabilized. The intake air is supplied from both the first intake port 19 and the second intake port 20 when the load is relatively high.

また、予混合圧縮自着火燃焼では対応できない火花点火燃焼の際に内部ＥＧＲを行う場合、第２吸気ポート２０のみから吸気を供給すると、吸気と内部ＥＧＲガスとの混合が大幅に促進されるため、自着火を起こすホットスポットが生じ難くなり、ノッキングが抑制される。   In addition, when internal EGR is performed during spark ignition combustion that cannot be handled by premixed compression self-ignition combustion, if intake air is supplied only from the second intake port 20, mixing of intake air and internal EGR gas is greatly promoted. , Hot spots that cause self-ignition are less likely to occur, and knocking is suppressed.

内部ＥＧＲは吸気行程の途中で第２の排気ポート２２を開閉することで行われる。図５は可変動弁機構２７，２８のバルブタイミングの一例を示す図である。吸気弁２３，２４及び排気弁２５，２６は、排気行程から吸気行程に移る際のピストン１５の上死点（ＴＤＣ）付近において開放状態のオーバーラップが存在するように開閉時期が設定されている。また、第２の排気ポート２２を開閉する排気弁２６は、排気行程においては排気弁２５と同じタイミングで開閉されるが、吸気行程において単独で開閉される。   The internal EGR is performed by opening and closing the second exhaust port 22 during the intake stroke. FIG. 5 is a diagram showing an example of the valve timing of the variable valve mechanisms 27 and 28. The intake valves 23 and 24 and the exhaust valves 25 and 26 are set to open and close so that there is an open overlap in the vicinity of the top dead center (TDC) of the piston 15 when moving from the exhaust stroke to the intake stroke. . The exhaust valve 26 that opens and closes the second exhaust port 22 is opened and closed at the same timing as the exhaust valve 25 in the exhaust stroke, but is opened and closed independently in the intake stroke.

予混合圧縮自着火機関１０の運転は図６のフローチャートに従って行われる。先ずステップＳ１で、暖機運転が行われる。制御装置１２はメモリ４７に記憶されている火花点火燃焼運転用のマップ（ＳＩ基本マップ）により、暖機運転の条件を満たす空燃比になるように、電磁制御弁３８及びスロットルモータ４１に指令信号を出力する。また、制御装置１２は、暖機運転の条件を満たす火花点火燃焼を行うのに適したバルブタイミング及び点火時期となるように、可変動弁機構２７，２８及び点火プラグ３３に指令信号を出力する。   The operation of the premixed compression auto-ignition engine 10 is performed according to the flowchart of FIG. First, in step S1, warm-up operation is performed. Based on the spark ignition combustion operation map (SI basic map) stored in the memory 47, the control device 12 sends a command signal to the electromagnetic control valve 38 and the throttle motor 41 so that the air-fuel ratio satisfies the warm-up operation condition. Is output. Further, the control device 12 outputs a command signal to the variable valve mechanisms 27 and 28 and the spark plug 33 so that the valve timing and the ignition timing are suitable for performing spark ignition combustion that satisfies the conditions for the warm-up operation. .

次に制御装置１２はステップＳ２で、水温センサ４８の検出信号に基づき、暖機が完了したか否かを判断する。即ち、水温センサ４８の検出温度が暖機が完了した状態の温度以上か否かを判断し、暖機が完了していればステップＳ３に進み、暖機が完了していなければステップＳ１に戻る。暖機が完了した状態の温度は、予め試験により求められてメモリ４７に記憶されている。   Next, in step S2, the control device 12 determines whether or not the warm-up is completed based on the detection signal of the water temperature sensor 48. That is, it is determined whether or not the temperature detected by the water temperature sensor 48 is equal to or higher than the temperature at which the warm-up is completed. If the warm-up is complete, the process proceeds to step S3. If the warm-up is not complete, the process returns to step S1. . The temperature in the state where the warm-up is completed is obtained in advance by a test and stored in the memory 47.

制御装置１２はステップＳ３で、要求回転速度及び負荷に対して冷却水温が規定値より大きいか否かを判断する。そして、冷却水温が規定値より大きければステップＳ４に進み、冷却水温が規定値以下であればステップＳ５に進む。前記規定値は、要求回転速度及び負荷に対応して予混合圧縮自着火燃焼（ＨＣＣＩ）運転を安定して行うことができる状態の機関本体１１の温度を予め試験で確認して設定されたものであり、メモリ４７に記憶されている。   In step S3, the control device 12 determines whether or not the cooling water temperature is higher than a specified value with respect to the required rotation speed and load. If the cooling water temperature is higher than the specified value, the process proceeds to step S4. If the cooling water temperature is equal to or lower than the specified value, the process proceeds to step S5. The specified value is set by checking beforehand the temperature of the engine body 11 in a state where the premixed compression auto-ignition combustion (HCCI) operation can be stably performed in accordance with the required rotational speed and load. And stored in the memory 47.

制御装置１２はステップＳ４で、要求回転速度及び負荷に対する予混合圧縮自着火燃焼運転可能領域を図３のマップＭ１から判断し、要求回転速度及び負荷に対する予混合圧縮自着火燃焼運転可能であればステップＳ６に進み、予混合圧縮自着火燃焼運転可能でなければステップＳ５に進む。制御装置１２はステップＳ５で、現在の水温において、要求回転速度及び負荷に対応する火花点火燃焼運転に適した空燃比となるように電磁制御弁３８及びスロットルモータ４１に指令信号を出力した後、ステップＳ３に進む。その結果、予混合圧縮自着火機関１０は要求回転速度及び負荷を満たすように火花点火燃焼で運転される。制御装置１２は、ステップＳ５において、内部ＥＧＲを行う場合は、第２吸気ポート２０のみから吸気を供給するように流量調整弁４４に指令信号を出力し、内部ＥＧＲを行わない場合は、第１吸気ポート１９及び第２吸気ポート２０から吸気を供給するように流量調整弁４４に指令信号を出力する。   In step S4, the control device 12 determines the premixed compression auto-ignition combustion operation possible region for the required rotational speed and load from the map M1 of FIG. The process proceeds to step S6, and if the premixed compression self-ignition combustion operation is not possible, the process proceeds to step S5. In step S5, the control device 12 outputs a command signal to the electromagnetic control valve 38 and the throttle motor 41 so that the air-fuel ratio suitable for the spark ignition combustion operation corresponding to the required rotational speed and load is output at the current water temperature. Proceed to step S3. As a result, the premixed compression self-ignition engine 10 is operated by spark ignition combustion so as to satisfy the required rotational speed and load. When performing internal EGR in step S5, the control device 12 outputs a command signal to the flow rate adjusting valve 44 so as to supply intake air only from the second intake port 20, and when not performing internal EGR, A command signal is output to the flow rate adjustment valve 44 so that intake air is supplied from the intake port 19 and the second intake port 20.

制御装置１２はステップＳ６で、要求回転速度及び負荷に対応する目標回転速度及び負荷に対して、目標内部ＥＧＲ量、空燃比及び吸気の供給状態を演算する。そして、その目標内部ＥＧＲ量、空燃比及び吸気の供給状態となるように、可変動弁機構２７，２８、電磁制御弁３８、スロットルモータ４１及び流量調整弁４４に指令信号を出力した後、ステップＳ３に進む。その結果、予混合圧縮自着火機関１０は要求回転速度及び負荷を満たすように予混合圧縮自着火燃焼で運転される。   In step S6, the control device 12 calculates the target internal EGR amount, the air-fuel ratio, and the intake air supply state with respect to the target rotation speed and load corresponding to the required rotation speed and load. Then, after outputting a command signal to the variable valve mechanisms 27, 28, the electromagnetic control valve 38, the throttle motor 41 and the flow rate adjusting valve 44 so that the target internal EGR amount, the air-fuel ratio and the intake air supply state are obtained, Proceed to S3. As a result, the premixed compression autoignition engine 10 is operated by premixed compression autoignition combustion so as to satisfy the required rotational speed and load.

ステップＳ６を詳述すると、制御装置１２は、目標回転速度及び負荷に対して、内部ＥＧＲ量及び空燃比を設定するだけでなく、吸気の供給状態も設定する。吸気の供給状態とは、第１吸気ポート１９及び第２吸気ポート２０からそれぞれどれだけ吸気が燃焼室１６に供給されるかを意味し、この実施形態では、吸気の供給状態を設定するとは流量調整弁４４の流量配分を設定することである。制御装置１２は、運転条件に応じて第１吸気ポート１９からのみ吸気を供給するか、第１吸気ポート１９及び第２吸気ポート２０から吸気を供給するかを判断して、運転条件に適した吸気の供給状態に流量調整弁４４を調整するように指令信号を出力する。   To describe step S6 in detail, the control device 12 not only sets the internal EGR amount and the air-fuel ratio with respect to the target rotational speed and load, but also sets the supply state of intake air. The intake air supply state means how much intake air is supplied from the first intake port 19 and the second intake port 20 to the combustion chamber 16, and in this embodiment, setting the intake air supply state is a flow rate. The flow distribution of the regulating valve 44 is set. The control device 12 determines whether the intake air is supplied only from the first intake port 19 or the intake air is supplied from the first intake port 19 and the second intake port 20 according to the operation condition, and is suitable for the operation condition. A command signal is output so as to adjust the flow rate adjustment valve 44 to the supply state of intake air.

この実施形態では以下の効果を有する。
（１）予混合圧縮自着火機関１０は、吸気行程の途中において排気ガスの一部を排気ポートから燃焼室１６内に逆流させる第２の排気ポート２２と、第２の排気ポート２２から燃焼室１６内に流入する排気ガス（内部ＥＧＲガス）の流れと同方向の流れとなるように吸気を燃焼室１６に供給する第１吸気ポート１９とを備えている。また、第２の排気ポート２２から燃焼室１６内に流入する排気ガスとの混合を促進するように吸気を燃焼室１６に供給する第２吸気ポート２０とを備えている。そして、少なくとも内部ＥＧＲガスと吸気との混合を促進したい場合に第２吸気ポート２０から吸気を供給するように流量調整弁４４を制御する制御装置１２を備えている。従って、内部ＥＧＲガスと吸気との混合が促進され、予混合圧縮自着火燃焼及び火花点火燃焼に限らず、安定して燃焼を行うことができる。 This embodiment has the following effects.
(1) The premixed compression self-ignition engine 10 includes a second exhaust port 22 that causes a part of the exhaust gas to flow backward from the exhaust port into the combustion chamber 16 during the intake stroke, and the second exhaust port 22 to the combustion chamber. A first intake port 19 is provided for supplying intake air to the combustion chamber 16 so that the exhaust gas flows in the same direction as the flow of exhaust gas (internal EGR gas) flowing into the combustion chamber 16. A second intake port 20 that supplies intake air to the combustion chamber 16 so as to promote mixing with the exhaust gas flowing into the combustion chamber 16 from the second exhaust port 22 is provided. A control device 12 is provided for controlling the flow rate adjusting valve 44 so as to supply intake air from the second intake port 20 when at least mixing of the internal EGR gas and intake air is desired to be promoted. Therefore, the mixing of the internal EGR gas and the intake air is promoted, and the combustion can be stably performed without being limited to the premixed compression self-ignition combustion and the spark ignition combustion.

（２）内燃機関は、燃料と酸素含有ガスとの混合気を燃焼室１６においてピストン１５で圧縮して自着火燃焼させ、ピストン１５の往復運動を出力軸（クランクシャフト１８）の回転運動とする予混合圧縮自着火機関１０である。そして、排気吸入ポート（第２の排気ポート２２）は燃焼室１６に流入する排気ガスが燃焼室１６の中心部に向かうように設けられ、第１吸気ポート１９は燃焼室１６に供給される吸気が燃焼室１６の内周面に沿う流れとなるように設けられている。また、第２吸気ポート２０は燃焼室１６に供給される吸気が燃焼室１６の内周面に沿う流れで第１吸気ポート１９から供給される吸気の流れと逆方向となるように設けられている。従って、内部ＥＧＲガスと混合気とは内部ＥＧＲガスが内側の層状になり、圧縮行程で圧縮されると、内部ＥＧＲガスと混合気との界面から予混合圧縮自着火燃焼が開始される。その結果、着火性が向上し、低負荷側における予混合圧縮自着火燃焼可能な範囲が拡大する。また、内部ＥＧＲガスが中心部に集まるため、内部ＥＧＲガスが少量でも温度を高くすることができ、内部ＥＧＲガス量を少なくでき、その分混合気の量が増やせるため、高負荷側における予混合圧縮自着火燃焼可能な範囲が拡大する。   (2) The internal combustion engine compresses the air-fuel mixture of fuel and oxygen-containing gas with the piston 15 in the combustion chamber 16 and burns it by self-ignition, and the reciprocating motion of the piston 15 is the rotational motion of the output shaft (crankshaft 18). This is a premixed compression self-ignition engine 10. The exhaust intake port (second exhaust port 22) is provided so that the exhaust gas flowing into the combustion chamber 16 is directed toward the center of the combustion chamber 16, and the first intake port 19 is the intake air supplied to the combustion chamber 16. Is provided to flow along the inner peripheral surface of the combustion chamber 16. The second intake port 20 is provided so that the intake air supplied to the combustion chamber 16 flows in a direction along the inner peripheral surface of the combustion chamber 16 and is opposite to the flow of intake air supplied from the first intake port 19. Yes. Accordingly, the internal EGR gas and the air-fuel mixture are layered on the inner side, and when they are compressed in the compression stroke, premixed compression auto-ignition combustion is started from the interface between the internal EGR gas and the air-fuel mixture. As a result, the ignitability is improved, and the premixed compression self-ignition combustion range on the low load side is expanded. In addition, since the internal EGR gas gathers in the center, the temperature can be increased even with a small amount of internal EGR gas, the amount of internal EGR gas can be reduced, and the amount of air-fuel mixture can be increased accordingly, so that premixing on the high load side The range in which compression auto-ignition combustion is possible is expanded.

（３）内部ＥＧＲガスが燃焼室１６の中心部に集められるため、圧縮された状態において、燃焼室１６中央から周壁面の間の温度の勾配が急になる。内部ＥＧＲガスと吸気とが均一に混合されると、圧縮された状態において前記温度の勾配はなだらかになり、ノッキングが発生し易くなる。しかし、この実施形態では前記のように温度の勾配が急になるため、予混合圧縮自着火燃焼においてノッキングが発生し難くなる。   (3) Since the internal EGR gas is collected at the center of the combustion chamber 16, the temperature gradient between the center of the combustion chamber 16 and the peripheral wall surface becomes steep in a compressed state. When the internal EGR gas and the intake air are uniformly mixed, the temperature gradient becomes gentle in the compressed state, and knocking is likely to occur. However, in this embodiment, since the temperature gradient becomes steep as described above, knocking hardly occurs in the premixed compression auto-ignition combustion.

（４）吸気の供給状態が、第１吸気ポートからのみ吸気を供給する状態と、第１吸気ポート及び第２吸気ポートから吸気を供給する状態とに変更可能なため、広い負荷条件において安定して予混合圧縮自着火燃焼を行うことができる。   (4) Since the supply state of intake air can be changed between a state in which intake air is supplied only from the first intake port and a state in which intake air is supplied from the first intake port and the second intake port, it is stable under a wide load condition. Thus, premixed compression self-ignition combustion can be performed.

（５）燃焼室１６には点火プラグ３３が装備されるとともに、排気ポートは複数設けられ、一つの排気ポート２２が排気吸入ポートとなっている。そして、制御装置１２は、内部ＥＧＲを行う火花点火燃焼運転時において第２吸気ポート２０からのみ吸気を供給する状態に流量調整弁４４を制御する。その結果、吸気と内部ＥＧＲガスとの混合がより促進され、自着火を起こすホットスポットを無くしてノッキングを抑制することができ、広い負荷条件において安定した燃焼を行うことができる。   (5) The combustion chamber 16 is equipped with an ignition plug 33, a plurality of exhaust ports are provided, and one exhaust port 22 serves as an exhaust intake port. Then, the control device 12 controls the flow rate adjustment valve 44 so that intake air is supplied only from the second intake port 20 during the spark ignition combustion operation in which internal EGR is performed. As a result, mixing of the intake air and the internal EGR gas is further promoted, a hot spot that causes self-ignition can be eliminated, knocking can be suppressed, and stable combustion can be performed under a wide load condition.

（６）第１吸気ポート１９及び第２吸気ポート２０からは、燃料と酸素含有ガスとの混合気が燃焼室１６に供給される。従って、いずれか一方の吸気ポートから燃料を供給し、他方の吸気ポートから酸素含有ガスを供給する構成に比較して、混合気を予混合圧縮自着火燃焼及び火花点火燃焼のいずれの場合においても適切な混合状態に制御するのが容易になる。   (6) From the first intake port 19 and the second intake port 20, an air-fuel mixture of fuel and oxygen-containing gas is supplied to the combustion chamber 16. Therefore, in comparison with the configuration in which the fuel is supplied from one of the intake ports and the oxygen-containing gas is supplied from the other intake port, the air-fuel mixture is either premixed compression auto-ignition combustion or spark ignition combustion. It becomes easy to control to an appropriate mixing state.

（７）排気ポートとして、排気を円滑に行う第１の排気ポート２１と、内部ＥＧＲを円滑に行う第２の排気ポート２２とが設けられている。従って、一つの排気ポートで排気と内部ＥＧＲとを行う構成に比較して、排気及び内部ＥＧＲの条件を満足できる構成が容易になる。   (7) As the exhaust port, a first exhaust port 21 that smoothly exhausts and a second exhaust port 22 that smoothly performs internal EGR are provided. Therefore, compared to a configuration in which exhaust and internal EGR are performed by one exhaust port, a configuration that can satisfy the conditions of exhaust and internal EGR is facilitated.

実施形態は前記に限定されるものではなく、例えば次のように構成してもよい。
○ 図７に示すように、排気吸入ポートとして使用される第２の排気ポート２２に流量調整手段５０が設けられた構成としてもよい。流量調整手段５０として、例えば、スロットルバルブが設けられる。この場合、第２の排気ポート２２（排気吸入ポート）から排気ガスを逆流させて内部ＥＧＲを行う場合、第２の排気ポート２２を開閉する排気弁２６の開閉時期が一定であっても、流量調整手段５０で流量を調整することにより、燃焼状態の制御性を高めることができ、より適正な状態で予混合圧縮自着火燃焼を行うことができる。 The embodiment is not limited to the above, and may be configured as follows, for example.
As shown in FIG. 7, it is good also as a structure by which the flow volume adjustment means 50 was provided in the 2nd exhaust port 22 used as an exhaust_gas | exhaustion inlet port. As the flow rate adjusting means 50, for example, a throttle valve is provided. In this case, when the internal EGR is performed by causing the exhaust gas to flow backward from the second exhaust port 22 (exhaust intake port), the flow rate is maintained even when the opening / closing timing of the exhaust valve 26 for opening / closing the second exhaust port 22 is constant. By adjusting the flow rate with the adjusting means 50, the controllability of the combustion state can be improved, and premixed compression self-ignition combustion can be performed in a more appropriate state.

○ 第１吸気ポート１９及び第２吸気ポート２０から燃焼室１６へ供給される吸気が燃焼室１６の内周面に沿って流入する形状となるように、シリンダヘッド１４に両吸気ポート１９，２０を作り込む代わりに、図７に示すように、フラップ５１を吸気ポート１９，２０に設けてもよい。フラップ５１は図示しないロータリソレノイドにより、鎖線で示す待機位置と実線で示す作用位置とに配置されるように構成される。フラップ５１は、待機位置に配置された状態では吸気ポート１９，２０を流れる吸気に殆ど影響を与えず、作用位置に配置された状態では吸気が偏流となって燃焼室１６の内周面に沿うように流入する。従って、燃焼室１６に流入する吸気の流れの状態を調整する自由度が高くなり、燃焼室１６内の吸気と内部ＥＧＲガスとの混合状態の自由度が高くなる。その結果、予混合圧縮自着火燃焼の制御性を高めることができる。   ○ Both intake ports 19, 20 are provided in the cylinder head 14 so that the intake air supplied from the first intake port 19 and the second intake port 20 to the combustion chamber 16 flows in along the inner peripheral surface of the combustion chamber 16. 7 may be provided in the intake ports 19 and 20 as shown in FIG. The flap 51 is configured to be disposed at a standby position indicated by a chain line and an operation position indicated by a solid line by a rotary solenoid (not shown). The flap 51 has little influence on the intake air flowing through the intake ports 19 and 20 when the flap 51 is disposed at the standby position, and the intake air is drifted along the inner peripheral surface of the combustion chamber 16 when disposed at the operation position. Inflow. Accordingly, the degree of freedom for adjusting the state of the flow of the intake air flowing into the combustion chamber 16 is increased, and the degree of freedom for the mixed state of the intake air in the combustion chamber 16 and the internal EGR gas is increased. As a result, the controllability of premixed compression auto-ignition combustion can be improved.

○ １個の流量調整弁４４で第１吸気ポート１９及び第２吸気ポート２０から燃焼室１６へ供給される吸気の供給量を制御する構成に代えて、図８に示すように、第１吸気ポート１９及び第２吸気ポート２０にそれぞれ流量調整弁５２ａ，５２ｂを設けてもよい。流量調整弁５２ａ，５２ｂはバタフライバルブの一種であり、アクチュエータ５３によって駆動されて全閉位置と全開位置との間で回動する。この場合、流量調整弁の構造が簡単で制御も容易となる。   Instead of a configuration in which the amount of intake air supplied from the first intake port 19 and the second intake port 20 to the combustion chamber 16 is controlled by one flow rate adjusting valve 44, as shown in FIG. The port 19 and the second intake port 20 may be provided with flow rate adjusting valves 52a and 52b, respectively. The flow rate adjusting valves 52a and 52b are a kind of butterfly valve, and are driven by an actuator 53 to rotate between a fully closed position and a fully open position. In this case, the structure of the flow rate adjusting valve is simple and control is easy.

○ 第１吸気ポート１９及び第２吸気ポート２０から燃焼室１６へ供給される吸気の供給量を制御する流量調整弁として、図９に示すように、第１吸気ポート１９及び第２吸気ポート２０と吸気通路３４との分岐部に、図示しないアクチュエータにより駆動される弁５４を設けてもよい。弁５４は、第１吸気ポート１９を全閉する鎖線で示す位置と、第２吸気ポート２０を全閉する実線で示す位置との間で回動される。   As shown in FIG. 9, the first intake port 19 and the second intake port 20 are used as flow rate adjustment valves for controlling the amount of intake air supplied from the first intake port 19 and the second intake port 20 to the combustion chamber 16. A valve 54 driven by an actuator (not shown) may be provided at a branch portion between the intake passage 34 and the intake passage 34. The valve 54 is rotated between a position indicated by a chain line that fully closes the first intake port 19 and a position indicated by a solid line that fully closes the second intake port 20.

○ 内部ＥＧＲを行う場合、予混合圧縮自着火機関１０の運転状態によっては、予混合圧縮自着火燃焼においても、吸気の供給を第２吸気ポート２０からのみ行うようにしてもよい。   When performing internal EGR, depending on the operating state of the premixed compression self-ignition engine 10, intake air may be supplied only from the second intake port 20 even in premixed compression self-ignition combustion.

○ 内部ＥＧＲを行う内部ＥＧＲ手段として、排気ガスを吸入する専用の排気吸入ポートを設け、該排気吸入ポートに開閉弁あるいは流量調整弁を設けた構成としてもよい。
○ 排気ポートを１個としてもよい。しかし、１個にした場合は、内部ＥＧＲガスを燃焼室１６の中心部に渦流として流入させ、排気行程で排気を円滑に行うように構成するのが難しい。 As an internal EGR means for performing internal EGR, a dedicated exhaust intake port for intake of exhaust gas may be provided, and an open / close valve or a flow rate adjusting valve may be provided in the exhaust intake port.
○ One exhaust port may be used. However, when the number is one, it is difficult to configure the internal EGR gas to flow into the central portion of the combustion chamber 16 as a vortex and smoothly exhaust in the exhaust stroke.

○ 予混合圧縮自着火機関１０の燃料は天然ガスに限らず、ガソリン、プロパンガス、メタノール、ジメチルエーテル、水素の他、ディーゼルエンジンで使用される燃料等任意の燃料を使用してもよい。   The fuel of the premixed compression self-ignition engine 10 is not limited to natural gas, and any fuel such as fuel used in a diesel engine may be used in addition to gasoline, propane gas, methanol, dimethyl ether, and hydrogen.

○ 点火プラグ３３を備えた構成において、暖機運転のときのみ火花点火燃焼で運転を行い、暖機完了後は予混合圧縮自着火燃焼で運転を行う構成としてもよい。
○ 暖機運転時のみ、燃料を圧縮自着火し易い燃料とし、暖機完了後に通常運転時の燃料に切り替える構成としてもよい。 In the configuration provided with the spark plug 33, the operation may be performed by the spark ignition combustion only during the warm-up operation, and the operation may be performed by the premixed compression self-ignition combustion after the warm-up is completed.
○ Only during warm-up operation, the fuel may be easily ignited by compression self-ignition, and after warm-up is completed, the fuel may be switched to the fuel during normal operation.

○ 混合気は燃料が気体である必要はなく、霧状の液体であってもよい。
○ 燃料と混合する酸素含有ガスは空気に限らず、燃料を燃焼させるのに必要な酸素を含む酸素含有ガスであればよい。例えば、空気に酸素を混合して酸素濃度を高めたガスを使用してもよい。 ○ The air-fuel mixture does not have to be gaseous fuel, and may be a mist-like liquid.
O The oxygen-containing gas mixed with the fuel is not limited to air, but may be any oxygen-containing gas containing oxygen necessary to burn the fuel. For example, a gas in which oxygen is mixed with air to increase the oxygen concentration may be used.

○ 内部ＥＧＲガスを燃焼室１６の周壁面に沿って流入するように排気吸入ポート（第２の排気ポート２２）を設け、吸気を第１吸気ポート１９及び第２吸気ポート２０から燃焼室１６の中心側に供給する構成としてもよい。この場合も混合気と内部ＥＧＲガスとが層状になるため、安定した予混合圧縮自着火燃焼が可能となる。また、第１吸気ポート１９及び第２吸気ポート２０からの吸気の供給状態を変更することで、広い負荷範囲において安定した予混合圧縮自着火燃焼あるいは火花点火燃焼を行うことができる。   An exhaust intake port (second exhaust port 22) is provided so that the internal EGR gas flows along the peripheral wall surface of the combustion chamber 16, and intake air is supplied from the first intake port 19 and the second intake port 20 to the combustion chamber 16. It is good also as a structure supplied to the center side. Also in this case, since the air-fuel mixture and the internal EGR gas are stratified, stable premixed compression self-ignition combustion becomes possible. Further, by changing the supply state of intake air from the first intake port 19 and the second intake port 20, it is possible to perform premixed compression self-ignition combustion or spark ignition combustion that is stable in a wide load range.

○ 予混合圧縮自着火機関１０に限らず、ディーゼルエンジンやガソリンエンジンに適用してもよい。
○ 吸気通路３４内に燃料を噴射して燃料と酸素含有ガスとを混合した混合気を燃焼室１６へ吸入する構成に限らず、燃料を吸気行程中に燃焼室１６に噴射する構成としてもよい。また、燃料はキャブレターやミキサー等で混合してもよい。 O You may apply not only to the premixed compression self-ignition engine 10 but to a diesel engine or a gasoline engine.
A configuration in which fuel is injected into the intake passage 34 to mix the fuel and oxygen-containing gas into the combustion chamber 16 is not limited, and fuel may be injected into the combustion chamber 16 during the intake stroke. . The fuel may be mixed with a carburetor or a mixer.

○ 予混合圧縮自着火機関１０はシリンダ（気筒）を複数備えた構成に限らず、単気筒であってもよい。
○ 吸気ポートを３個以上設けたり、排気ポートを３個以上設けたりしてもよい。 The premixed compression self-ignition engine 10 is not limited to a configuration having a plurality of cylinders, and may be a single cylinder.
○ Three or more intake ports may be provided, or three or more exhaust ports may be provided.

○ 可変動弁機構２７，２８は、カムシャフト２９，３０を使用してカム３１，３２により又はロッカアームを介して吸気弁２３，２４あるいは排気弁２５，２６を開閉作動させる構成に限らない。例えば、可変動弁機構２７，２８として、電磁駆動装置又は油圧アクチュエータで直接各吸気弁２３，２４あるいは排気弁２５，２６を開閉作動させる構成を採用してもよい。この場合、開閉時期の調整の自由度が高くなる。   The variable valve mechanisms 27 and 28 are not limited to the configuration in which the intake valves 23 and 24 or the exhaust valves 25 and 26 are opened / closed using the cam shafts 29 and 30 by the cams 31 and 32 or via the rocker arm. For example, the variable valve mechanisms 27 and 28 may employ a configuration in which the intake valves 23 and 24 or the exhaust valves 25 and 26 are directly opened and closed by an electromagnetic drive device or a hydraulic actuator. In this case, the degree of freedom in adjusting the opening / closing timing is increased.

○ 予混合圧縮自着火機関１０は定置式のものに限らず、自動車のエンジンに適用してもよい。
以下の技術的思想（発明）は前記実施形態から把握できる。 The premixed compression self-ignition engine 10 is not limited to a stationary type, and may be applied to an automobile engine.
The following technical idea (invention) can be understood from the embodiment.

（１）請求項１〜請求項４のいずれか一項に記載の発明において、前記第１吸気ポート及び第２吸気ポートからは、燃料と酸素含有ガスとの混合気が燃焼室に供給される。
（２）請求項１〜請求項４及び前記技術的思想（１）のいずれか一項に記載の発明において、前記流量調整弁は前記第１吸気ポート及び第２吸気ポートにそれぞれ設けられている。 (1) In the invention according to any one of claims 1 to 4, an air-fuel mixture of fuel and oxygen-containing gas is supplied to the combustion chamber from the first intake port and the second intake port. .
(2) In the invention according to any one of claims 1 to 4 and the technical idea (1), the flow rate adjusting valve is provided in each of the first intake port and the second intake port. .

吸気ポートと排気ポートとの関係を示す模式平面図。The schematic plan view which shows the relationship between an intake port and an exhaust port. 予混合圧縮自着火機関の概略構成図。1 is a schematic configuration diagram of a premixed compression self-ignition engine. ＨＣＣＩ可能な範囲を機関の回転速度及び負荷との関係で示すマップ。A map showing the range in which HCCI is possible in relation to the engine speed and load. （ａ）は第１吸気ポートからのみ吸気が供給される状態の模式図、（ｂ）は第１吸気ポート及び第２吸気ポートから吸気が供給される状態の模式図。(A) is a schematic diagram in a state where intake air is supplied only from a first intake port, and (b) is a schematic diagram in a state where intake air is supplied from a first intake port and a second intake port. 吸気弁及び排気弁の開閉時期を示す図。The figure which shows the opening / closing timing of an intake valve and an exhaust valve. 予混合圧縮自着火機関の運転制御を説明するフローチャート。The flowchart explaining the operation control of a premixed compression self-ignition engine. 別の実施形態の吸気ポートと排気ポートを示す模式平面図。The schematic plan view which shows the intake port and exhaust port of another embodiment. 別の実施形態の流量調整弁を示す模式平面図。The schematic plan view which shows the flow regulating valve of another embodiment. 別の実施形態の流量調整弁を示す模式平面図。The schematic plan view which shows the flow regulating valve of another embodiment. 従来技術のガソリンエンジンの部分平面図。The partial top view of the gasoline engine of a prior art.

符号の説明Explanation of symbols

１０…予混合圧縮自着火機関、１２…制御手段としての制御装置、１５…ピストン、１６…燃焼室、１８…出力軸としてのクランクシャフト、１９…第１吸気ポート、２０…第２吸気ポート、２１…第１の排気ポート、２２…排気吸入ポートとしての第２の排気ポート、３３…点火装置としての点火プラグ、４４，５２ａ，５２ｂ…流量調整弁、５０…流量調整手段。   DESCRIPTION OF SYMBOLS 10 ... Premixed compression self-ignition engine, 12 ... Control apparatus as a control means, 15 ... Piston, 16 ... Combustion chamber, 18 ... Crankshaft as an output shaft, 19 ... 1st intake port, 20 ... 2nd intake port, DESCRIPTION OF SYMBOLS 21 ... 1st exhaust port, 22 ... 2nd exhaust port as exhaust suction port, 33 ... Spark plug as ignition device, 44, 52a, 52b ... Flow rate adjustment valve, 50 ... Flow rate adjustment means.

Claims (4)

吸気行程の途中において排気ガスの一部を排気ポートから燃焼室内に逆流させる内部ＥＧＲを行う内部ＥＧＲ手段と、
前記内部ＥＧＲ手段を構成し、排気ガスの一部を燃焼室内に逆流させる排気吸入ポートと、
前記排気吸入ポートから前記燃焼室内に流入する排気ガスの流れと同方向の流れとなるように吸気を前記燃焼室に供給する第１吸気ポートと、
前記排気吸入ポートから前記燃焼室内に流入する排気ガスとの混合を促進するように吸気を前記燃焼室に供給する第２吸気ポートと、
前記第１吸気ポート及び第２吸気ポートから前記燃焼室へ供給される吸気の供給量を制御可能な流量調整弁と、
機関の運転条件に基づいて前記流量調整弁を制御し、内部ＥＧＲガスと吸気との混合を促進したい場合に前記第２吸気ポートからのみ吸気を供給するように前記流量調整弁を制御する制御手段と
を備えている内燃機関。 Internal EGR means for performing internal EGR for causing a part of the exhaust gas to flow backward from the exhaust port into the combustion chamber during the intake stroke;
An exhaust intake port that constitutes the internal EGR means and reversely flows a part of the exhaust gas into the combustion chamber;
A first intake port for supplying intake air to the combustion chamber so as to flow in the same direction as the flow of exhaust gas flowing into the combustion chamber from the exhaust intake port;
A second intake port for supplying intake air to the combustion chamber so as to promote mixing with the exhaust gas flowing into the combustion chamber from the exhaust intake port;
A flow rate adjustment valve capable of controlling a supply amount of intake air supplied from the first intake port and the second intake port to the combustion chamber;
Control means for controlling the flow rate adjusting valve based on engine operating conditions and controlling the flow rate adjusting valve so as to supply intake air only from the second intake port when it is desired to promote mixing of internal EGR gas and intake air. And an internal combustion engine. 内燃機関は、燃料と酸素含有ガスとの混合気を燃焼室においてピストンで圧縮して自着火燃焼させ、前記ピストンの往復運動を出力軸の回転運動とする予混合圧縮自着火機関であり、前記排気吸入ポートは前記燃焼室に流入する排気ガスが前記燃焼室の中心部に向かうように設けられ、前記第１吸気ポートは前記燃焼室に供給される吸気が前記燃焼室の内周面に沿う流れとなるように設けられ、前記第２吸気ポートは前記燃焼室に供給される吸気が前記燃焼室の内周面に沿う流れで前記第１吸気ポートから供給される吸気の流れと逆方向となるように設けられている請求項１に記載の内燃機関。   The internal combustion engine is a premixed compression self-ignition engine in which an air-fuel mixture of fuel and oxygen-containing gas is compressed by a piston in a combustion chamber and self-ignition combustion is performed, and the reciprocating motion of the piston is a rotational motion of an output shaft, The exhaust intake port is provided so that exhaust gas flowing into the combustion chamber is directed toward the center of the combustion chamber, and the first intake port is configured such that the intake air supplied to the combustion chamber is along the inner peripheral surface of the combustion chamber The second intake port is configured to flow, and the intake air supplied to the combustion chamber flows in a direction along the inner peripheral surface of the combustion chamber, and has a direction opposite to the flow of intake air supplied from the first intake port. The internal combustion engine according to claim 1, wherein the internal combustion engine is provided as follows. 前記燃焼室には点火装置が装備されるとともに、排気ポートは複数設けられ、一つの排気ポートが前記排気吸入ポートとなり、前記制御手段は、内燃機関の内部ＥＧＲを伴う運転条件に応じて、予混合圧縮自着火燃焼運転時において前記第１吸気ポートからのみ吸気を供給する状態と、予混合圧縮自着火燃焼運転時において前記第１吸気ポート及び第２吸気ポートの両方から吸気を供給する状態と、火花点火燃焼運転時において前記第２吸気ポートからのみ吸気を供給する状態とに前記流量調整弁を制御する請求項２に記載の内燃機関。   The combustion chamber is equipped with an ignition device, and a plurality of exhaust ports are provided. One exhaust port serves as the exhaust intake port, and the control means preliminarily operates in accordance with operating conditions involving internal EGR of the internal combustion engine. A state in which intake air is supplied only from the first intake port during the mixed compression auto-ignition combustion operation, and a state in which intake air is supplied from both the first intake port and the second intake port during the pre-mixed compression auto-ignition combustion operation. The internal combustion engine according to claim 2, wherein the flow rate adjusting valve is controlled so that intake air is supplied only from the second intake port during spark ignition combustion operation. 前記燃焼室に排気ポートが２個接続され、一方の排気ポートが前記排気吸入ポートとなり、該排気吸入ポートには流量調整手段が設けられている請求項１〜請求項３のいずれか一項に記載の内燃機関。   The exhaust port is connected to the combustion chamber, one exhaust port serves as the exhaust suction port, and the exhaust suction port is provided with a flow rate adjusting means. The internal combustion engine described.
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