JP2013060863A - Internal combustion engine control device - Google Patents
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Abstract
Description
本発明は、内燃機関の制御装置に関し、詳しくは、吸気通路内に燃料を噴射する燃料噴射弁の噴射開始時期を制御する技術に関する。 The present invention relates to a control device for an internal combustion engine, and more particularly to a technique for controlling an injection start timing of a fuel injection valve that injects fuel into an intake passage.
従来、燃焼室内を内部ＥＧＲガス層と可燃混合気層とに分け、前記可燃混合気層に着火して燃焼させるＥＧＲ成層燃焼を実現する内燃機関として、ピストンが上昇する排気行程時に、第１吸気弁を介して上流側の第１吸気ポートにＥＧＲガスを導入し、ピストンが上死点から下降する吸気行程時に、第１吸気ポート内に導入したＥＧＲガスを、前記第１吸気弁を介して燃焼室に導入すると共に、第２吸気弁を介して上流側の第２吸気ポート内の新気を燃焼室内に導入してＥＧＲ成層燃焼を行わせる内燃機関があった（例えば、特許文献１参照）。 Conventionally, as an internal combustion engine that realizes EGR stratified combustion in which the combustion chamber is divided into an internal EGR gas layer and a combustible mixture layer, and the combustible mixture layer is ignited and burned, EGR gas is introduced into the first intake port on the upstream side through the valve, and EGR gas introduced into the first intake port during the intake stroke in which the piston descends from the top dead center is passed through the first intake valve. There has been an internal combustion engine that introduces fresh air in the second intake port on the upstream side into the combustion chamber through the second intake valve and introduces EGR stratified combustion through the second intake valve (see, for example, Patent Document 1). ).
ところで、２つの吸気弁の一方から内部ＥＧＲガスをシリンダ内に導入し、他方から新気をシリンダ内に導入するようにすると、ＥＧＲ運転領域を高出力側に拡大しようとしても、片側の吸気弁から導入される新気分のエンジントルクしか発生させることができないため、エンジントルクを確保しつつＥＧＲ運転領域を高出力側に拡大させることが困難であった。 By the way, if the internal EGR gas is introduced into the cylinder from one of the two intake valves and the fresh air is introduced into the cylinder from the other, the intake valve on one side may be expanded even if the EGR operation area is expanded to the high output side. Therefore, it is difficult to expand the EGR operation region to the high output side while securing the engine torque.
そこで、本願発明は、ＥＧＲ運転領域の拡大によって燃費性能を向上させると共に、ＥＧＲ運転中のエンジントルクを確保できる内燃機関の制御装置を提供することを目的とする。 Accordingly, an object of the present invention is to provide a control device for an internal combustion engine that can improve the fuel consumption performance by expanding the EGR operation region and can secure the engine torque during the EGR operation.
そのため、本願発明は、吸気通路内に燃料を噴射する燃料噴射弁を備えた内燃機関において、吸気通路内に導入される燃焼ガス量が多いほど燃料噴射弁による噴射開始時期をより遅い時期に設定し、かつ、吸気通路内を流れる吸入空気の流速が遅いほど前記噴射開始時期をより遅い時期に設定するようにした。 Therefore, according to the present invention, in an internal combustion engine having a fuel injection valve that injects fuel into the intake passage, the injection start timing by the fuel injection valve is set to a later timing as the amount of combustion gas introduced into the intake passage increases. In addition, as the flow rate of the intake air flowing through the intake passage is slower, the injection start timing is set to a later timing.
上記発明によると、ＥＧＲガスに続けてシリンダ内に導入される新気の導入時期に合わせて、燃料噴射弁の噴射開始時期を設定できるので、新気に噴射燃料を混合でき、エンジントルクを向上させることができると共に、ＥＧＲ効果によって燃費向上を図ることができる。 According to the above invention, the injection start timing of the fuel injection valve can be set in accordance with the introduction timing of the fresh air introduced into the cylinder following the EGR gas, so that the injected fuel can be mixed with fresh air and the engine torque is improved. In addition, fuel efficiency can be improved by the EGR effect.
以下に本発明に係る内燃機関の制御装置の実施形態を説明する。
図１は、本発明に係る制御装置を適用する車両用エンジン（内燃機関）のシステム構成を示す図である。
尚、図１に示すエンジン１０１は、直列型多気筒内燃機関であるが、Ｖ型や水平対向型などの内燃機関であってもよい。
Embodiments of a control device for an internal combustion engine according to the present invention will be described below.
FIG. 1 is a diagram showing a system configuration of a vehicle engine (internal combustion engine) to which a control device according to the present invention is applied.
The engine 101 shown in FIG. 1 is an in-line multi-cylinder internal combustion engine, but may be a V-type or a horizontally opposed internal combustion engine.
エンジン１０１の各気筒に空気を導入するための吸気管（吸気通路）１０２には、エンジン１０１の吸入空気流量ＱＡを検出する吸入空気量センサ１０３を設けてある。吸入空気量センサ１０３として、例えば、吸気の質量流量を検出する熱線式流量計などを用いることができる。
エンジン１０１の吸入空気流量ＱＡは、吸入空気量センサ１０３下流側の吸気管１０２に配置した電子制御スロットル１１９によって調整される。
An intake pipe (intake passage) 102 for introducing air into each cylinder of the engine 101 is provided with an intake air amount sensor 103 that detects an intake air flow rate QA of the engine 101. As the intake air amount sensor 103, for example, a hot-wire flow meter that detects the mass flow rate of intake air can be used.
The intake air flow rate QA of the engine 101 is adjusted by an electronic control throttle 119 disposed in the intake pipe 102 on the downstream side of the intake air amount sensor 103.
図２に示すように、各燃焼室１０４には２つの吸気口１１５ａ，１１５ｂが開口し、各吸気口１１５ａ，１１５ｂに至る２つの吸気ポート１１３ａ，１１３ｂが気筒毎に設けられ、かつ、各吸気口１１５ａ，１１５ｂを開閉する２つの吸気弁１０５ａ，１０５ｂを設けてある。更に、第１吸気ポート１１３ａ内に燃料を噴射する第１燃料噴射弁１０６ａと、第２吸気ポート１１３ｂ内に燃料を噴射する第１燃料噴射弁１０６ａとを設けてある。
尚、第１吸気弁１０５ａ上流側の第１吸気ポート１１３ａと第２吸気弁１０５ｂ上流側の第２吸気ポート１１３ｂとが合流して吸気管１０２に接続される。
As shown in FIG. 2, each combustion chamber 104 has two intake ports 115a and 115b, two intake ports 113a and 113b reaching each intake port 115a and 115b are provided for each cylinder, and each intake port Two intake valves 105a and 105b for opening and closing the ports 115a and 115b are provided. Further, a first fuel injection valve 106a for injecting fuel into the first intake port 113a and a first fuel injection valve 106a for injecting fuel into the second intake port 113b are provided.
The first intake port 113a on the upstream side of the first intake valve 105a and the second intake port 113b on the upstream side of the second intake valve 105b merge and are connected to the intake pipe 102.
燃料噴射弁１０６ａ，１０６ｂから噴射された燃料は、吸気行程で吸気弁１０５ａ，１０５ｂが開くことで燃焼室１０４内に導入され、点火プラグ１０７による火花点火によって着火燃焼し、該燃焼による圧力がピストン１０８をクランクシャフト１０９に向けて押し下げることで、クランクシャフト１０９を回転駆動する。
また、図２に示すように、各燃焼室１０４には２つの排気口１１７ａ，１１７ｂが開口し、各排気口１１７ａ，１１７ｂを開閉する２つの排気弁１１０ａ，１１０ｂを備え、この排気弁１１０ａ，１１０ｂが排気行程で開くことで、燃焼ガス（排ガス）が排気管（排気通路）１１１に排出される。
排気管１１１には、排気の浄化を行うために、三元触媒等を備えた触媒コンバータ１１２を設置してある。
The fuel injected from the fuel injection valves 106a and 106b is introduced into the combustion chamber 104 by opening the intake valves 105a and 105b in the intake stroke, and ignited and burned by spark ignition by the spark plug 107, and the pressure by the combustion is changed to the piston. The crankshaft 109 is rotationally driven by pushing down 108 toward the crankshaft 109.
As shown in FIG. 2, each combustion chamber 104 has two exhaust ports 117a and 117b and two exhaust valves 110a and 110b for opening and closing the exhaust ports 117a and 117b. The combustion gas (exhaust gas) is discharged to the exhaust pipe (exhaust passage) 111 by opening 110b in the exhaust stroke.
In the exhaust pipe 111, a catalytic converter 112 including a three-way catalyst is installed in order to purify the exhaust gas.
吸気弁１０５ａ，１０５ｂは、クランクシャフト１０９によって回転駆動される吸気カムシャフト（図示省略）の回転に伴って開動作し、排気弁１１０ａ，１１０ｂは、クランクシャフト１０９によって回転駆動される排気カムシャフト（図示省略）の回転に伴って開動作する。
また、排気弁１１０ａ，１１０ｂは、一定のバルブタイミング（開特性）で開動作するが、吸気弁１０５ａ，１０５ｂのバルブタイミング（開時期ＩＶＯ及び閉時期ＩＶＣ）は、可変動弁機構１１４ａ，１１４ｂによって可変とされる。
The intake valves 105a and 105b open as the intake camshaft (not shown) rotated by the crankshaft 109 is rotated, and the exhaust valves 110a and 110b are exhaust camshaft (rotated by the crankshaft 109). It opens with the rotation of (not shown).
The exhaust valves 110a and 110b open at a constant valve timing (open characteristic), but the valve timings (open timing IVO and close timing IVC) of the intake valves 105a and 105b are controlled by the variable valve mechanisms 114a and 114b. Variable.
第１可変動弁機構１１４ａは、クランクシャフト１０９に対する吸気カムシャフトの回転位相を変化させることで、吸気弁１０５ａ，１０５ｂのバルブ作動角の中心位相を連続的に変化させる公知の機構である。
一方、第２可変動弁機構１１４ｂは、第１吸気弁１０５ａのバルブタイミング（開特性）を変化させることなく、第２吸気弁１０５ｂのバルブタイミング（開特性）を独立して可変とする機構であり、この第２可変動弁機構１１４ｂによって第２吸気弁１０５ｂのバルブタイミング（開特性）を、第１吸気弁１０５ａと同じタイミングから異なるタイミングにまで変化させることができるようになっている。
The first variable valve mechanism 114a is a known mechanism that continuously changes the center phase of the valve operating angle of the intake valves 105a and 105b by changing the rotational phase of the intake camshaft with respect to the crankshaft 109.
On the other hand, the second variable valve mechanism 114b is a mechanism that makes the valve timing (opening characteristic) of the second intake valve 105b variable independently without changing the valve timing (opening characteristic) of the first intake valve 105a. The second variable valve mechanism 114b can change the valve timing (open characteristic) of the second intake valve 105b from the same timing as the first intake valve 105a to a different timing.
第２可変動弁機構１１４ｂとしては、例えば、特開２００８−２５５８６６号公報に開示される、制御軸の角度を変化させることで、吸気弁の最大バルブリフト量をバルブ作動角と共に連続的に可変とするリフト及び作動角可変機構や、同じく特開２００８−２５５８６６号公報に開示される、吸気弁の駆動に用いるカムを、大作動角カムと小作動角カムとのいずれか一方に切り替えるカム切替機構などを用いることができる。
ここで、第２可変動弁機構１１４ｂとしてカム切替機構を用いる場合、図３に示すように、大作動角カムの選択時には、第１吸気弁１０５ａ及び第２吸気弁１０５ｂのバルブリフト量（最大バルブリフト量）及びバルブ作動角が略同等になり、小作動角カムの選択時には、第２吸気弁１０５ｂのバルブリフト量及びバルブ作動角が第１吸気弁１０５ａのバルブリフト量及びバルブ作動角よりも小さくなるように設定してある。
As the second variable valve mechanism 114b, for example, the maximum valve lift amount of the intake valve is continuously variable together with the valve operating angle by changing the angle of the control shaft disclosed in Japanese Patent Laid-Open No. 2008-255866. Cam switching for switching the cam used for driving the intake valve to one of a large operating angle cam and a small operating angle cam, which is also disclosed in Japanese Patent Application Laid-Open No. 2008-255866. A mechanism or the like can be used.
Here, when a cam switching mechanism is used as the second variable valve mechanism 114b, as shown in FIG. 3, when the large operating angle cam is selected, the valve lift amounts (maximum) of the first intake valve 105a and the second intake valve 105b are selected. The valve lift amount and the valve operating angle are substantially equal, and when the small operating angle cam is selected, the valve lift amount and valve operating angle of the second intake valve 105b are larger than the valve lift amount and valve operating angle of the first intake valve 105a. Is set to be smaller.
また、第２可変動弁機構１１４ｂとして、リフト及び作動角可変機構を用いる場合には、図４に示すように、第２吸気弁１０５ｂのバルブリフト量（最大バルブリフト量）及びバルブ作動角の可変範囲には、第１吸気弁１０５ｂのバルブリフト量及びバルブ作動角と同じバルブリフト量及びバルブ作動角と、前記小作動角カムの選択時のバルブリフト量及びバルブ作動角とを少なくとも含むように設定する。
このように、第２可変動弁機構１１４ｂは、第２吸気弁１０５ｂの開弁特性を、第１吸気弁１０５ａと同じ特性と、第１吸気弁１０５ａよりもバルブリフト量及びバルブ作動角が小さい特性とのいずれかに切り替えられる機構である。
When a lift and operating angle variable mechanism is used as the second variable valve mechanism 114b, as shown in FIG. 4, the valve lift amount (maximum valve lift amount) and the valve operating angle of the second intake valve 105b are adjusted. The variable range includes at least the valve lift amount and the valve operating angle that are the same as the valve lift amount and the valve operating angle of the first intake valve 105b, and the valve lift amount and the valve operating angle when the small operating angle cam is selected. Set to.
As described above, the second variable valve mechanism 114b has the same valve opening characteristics as the first intake valve 105a and a smaller valve lift and valve operating angle than the first intake valve 105a. It is a mechanism that can be switched to one of the characteristics.
点火プラグ１０７それぞれには、点火プラグ１０７に対して点火エネルギを供給する点火モジュール１１６が直付けされている。点火モジュール１１６は、点火コイル及び当該点火コイルへの通電を制御するパワートランジスタを備えている。
エンジン制御装置（エンジンコントロールユニット）２０１は、ＣＰＵ，ＲＯＭ，ＲＡＭなどを含むコンピュータを備え、各種のセンサやスイッチからの信号を入力し、予め記憶されたプログラムに従って演算処理を行うことで、燃料噴射弁１０６、可変動弁機構１１４ａ，１１４ｂ、点火モジュール１１６などの各種デバイスの操作量を演算して出力する装置であり、本願発明に係る制御装置としての機能を後述するように備えている。
Each ignition plug 107 is directly attached with an ignition module 116 that supplies ignition energy to the ignition plug 107. The ignition module 116 includes an ignition coil and a power transistor that controls energization of the ignition coil.
The engine control device (engine control unit) 201 includes a computer including a CPU, a ROM, a RAM, etc., inputs signals from various sensors and switches, and performs arithmetic processing according to a program stored in advance, thereby injecting fuel. It is a device that calculates and outputs operation amounts of various devices such as the valve 106, the variable valve mechanisms 114a and 114b, and the ignition module 116, and has a function as a control device according to the present invention as described later.
また、エンジン制御装置２０１は、吸入空気量センサ１０３の出力信号を入力する他、クランクシャフト１０９の回転角信号ＰＯＳを出力するクランク角センサ２０３、アクセルペダル２０７の踏込み量（アクセル開度ＡＣＣ）を検出するアクセル開度センサ２０６、吸気カムシャフトの回転角信号ＣＡＭを出力するカム角センサ２０４、エンジン１０１の冷却水の温度（機関温度）ＴＷを検出する水温センサ２０８、触媒コンバータ１１２上流側の排気管１１１に設置され、排気中の酸素濃度に基づいて空燃比ＡＦを検出する空燃比センサ２０９、電子制御スロットル１１９の開度ＴＶＯを検出するスロットルセンサ２１０、電子制御スロットル１１９と吸気弁１０５ａ，１０５ｂとの間の吸気管（吸気通路）１０２内の圧力である吸気負圧（ブースト）ＰＢを検出する吸気圧センサ１２１などからの信号を入力し、更に、エンジン１０１の運転及び停止のメインスイッチであるイグニッションスイッチ（ＩＧＮスイッチ）２０５の信号を入力する。
ここで、エンジン制御装置２０１は、クランク角センサ２０３が出力する回転角信号ＰＯＳに基づいてエンジン回転速度ＮＥを算出する。
Further, the engine control device 201 inputs the output signal of the intake air amount sensor 103, the crank angle sensor 203 that outputs the rotation angle signal POS of the crankshaft 109, and the depression amount (accelerator opening ACC) of the accelerator pedal 207. Accelerator opening sensor 206 for detecting, cam angle sensor 204 for outputting the rotation angle signal CAM of the intake camshaft, water temperature sensor 208 for detecting the temperature (engine temperature) TW of the engine 101, exhaust on the upstream side of the catalytic converter 112 An air-fuel ratio sensor 209 that is installed in the pipe 111 and detects the air-fuel ratio AF based on the oxygen concentration in the exhaust, a throttle sensor 210 that detects the opening TVO of the electronic control throttle 119, the electronic control throttle 119, and the intake valves 105a and 105b Negative pressure which is the pressure in the intake pipe (intake passage) 102 between (Boost) receives signals from such an intake air pressure sensor 121 for detecting a PB, further, inputs the signal of the ignition switch (IGN switch) 205 is a main switch of the operation and stopping of the engine 101.
Here, the engine control device 201 calculates the engine rotation speed NE based on the rotation angle signal POS output from the crank angle sensor 203.
次に、エンジン制御装置２０１による可変動弁機構１１４ａ，１１４ｂの制御を、概略的に説明する。
例えばエンジン１０１の低負荷低回転域など、燃費性能が要求される運転領域では、第１可変動弁機構１１４ａによって吸気カムシャフトの回転位相を進角させると共に、第２可変動弁機構１１４ａによって第２吸気弁１０５ｂのバルブ作動角を第１吸気弁１０５ａよりも小さくすることで、第１吸気弁１０５ａの開時期ＩＶＯを上死点ＴＤＣ前に設定し、第２吸気弁１０５ｂの開時期ＩＶＯを略上死点ＴＤＣ以降に設定し、第１吸気弁１０５ａの閉時期ＩＶＣ及び第２吸気弁１０５ｂの閉時期ＩＶＣを下死点ＢＤＣ以降の略同じ時期に設定する。
尚、排気弁１１０ａ，１１０ｂの閉時期ＥＶＣは、上死点ＴＤＣ付近に設定してある。
Next, the control of the variable valve mechanisms 114a and 114b by the engine control device 201 will be schematically described.
For example, in an operation region where fuel efficiency is required, such as a low load low rotation region of the engine 101, the rotational phase of the intake camshaft is advanced by the first variable valve mechanism 114a and the second variable valve mechanism 114a 2 By making the valve operating angle of the intake valve 105b smaller than the first intake valve 105a, the opening timing IVO of the first intake valve 105a is set before the top dead center TDC, and the opening timing IVO of the second intake valve 105b is set. The timing is set substantially after the top dead center TDC, and the closing timing IVC of the first intake valve 105a and the closing timing IVC of the second intake valve 105b are set to substantially the same timing after the bottom dead center BDC.
The closing timing EVC of the exhaust valves 110a and 110b is set near the top dead center TDC.
これにより、第１吸気弁１０５ａは、ピストン上昇中の排気行程（上死点ＴＤＣ前）で開くことになり、第１吸気弁１０５ａがピストン上昇中に開くと、燃焼室１０４内の燃焼ガス（燃焼後の排ガス）は、第１吸気弁１０５ａ上流の第１吸気ポート１１３ａに吹き返すことになる。
そして、第１吸気弁１０５ａの開状態で、ピストンが上死点ＴＤＣに達するまでに、第１吸気ポート１１３ａに吹き返した燃焼ガス（内部ＥＧＲガス）は、ピストンが上死点ＴＤＣから下降に転じて吸気行程に切り替わることで燃焼室１０４内に再度吸入され、内部ＥＧＲガスの吸入に続けて新気が第１吸気弁１０５ａを介して燃焼室１０４内に吸入されることになる（燃焼ガス導入手段）。
As a result, the first intake valve 105a is opened during the exhaust stroke (before the top dead center TDC) while the piston is rising. When the first intake valve 105a is opened while the piston is rising, the combustion gas in the combustion chamber 104 ( The exhaust gas after combustion) is blown back to the first intake port 113a upstream of the first intake valve 105a.
Then, the combustion gas (internal EGR gas) blown back to the first intake port 113a before the piston reaches the top dead center TDC in the opened state of the first intake valve 105a causes the piston to descend from the top dead center TDC. By switching to the intake stroke, the air is sucked again into the combustion chamber 104, and fresh air is sucked into the combustion chamber 104 via the first intake valve 105a following the intake of the internal EGR gas (introduction of combustion gas). means).
一方、第２吸気弁１０５ｂは、ピストン上昇中の排気行程（上死点ＴＤＣ前）では開弁せず、ピストンが上死点ＴＤＣに達した以降の吸気行程で開くので、第２吸気弁１０５ｂの上流側の第２吸気ポート１１３ｂに対する燃焼ガスの吹き返し（内部ＥＧＲ）は発生せず、第２吸気弁１０５ｂを介しては、新気が燃焼室１０４内に吸入される。
そして、第１吸気弁１０５ａを介した燃焼室１０４内への内部ＥＧＲガス及び新気の吸入動作に並行して、第２吸気弁１０５ｂを介して新気が燃焼室１０４内に吸入されるので、燃焼室１０４内におけるスワール（横向きの吸気渦流）の形成が抑制される。
On the other hand, the second intake valve 105b does not open during the exhaust stroke (before the top dead center TDC) while the piston is rising, and opens during the intake stroke after the piston reaches the top dead center TDC. No combustion gas blows back (internal EGR) into the second intake port 113b on the upstream side of the engine, and fresh air is drawn into the combustion chamber 104 through the second intake valve 105b.
In parallel with the operation of sucking the internal EGR gas and fresh air into the combustion chamber 104 via the first intake valve 105a, fresh air is sucked into the combustion chamber 104 via the second intake valve 105b. The formation of swirls (lateral intake vortex flow) in the combustion chamber 104 is suppressed.
これにより、第１吸気弁１０５ａを介した吸入動作の初期に燃焼室１０４内に吸入された内部ＥＧＲガスが、新気と混じることが抑制され、燃焼室１０４内で新気層と内部ＥＧＲガス層とに成層化してＥＧＲ成層燃焼を行わせることができ、大量内部ＥＧＲと新気に対する燃料の混合とによって、燃焼室１０４全体としては空燃比を大きくリーン化させて燃費の向上を図ることができる。
但し、内部ＥＧＲガス中に燃料が混じると、成層度が低下し、内部ＥＧＲ量の増大を図ることができなくなる。
As a result, the internal EGR gas sucked into the combustion chamber 104 at the initial stage of the intake operation via the first intake valve 105 a is suppressed from being mixed with fresh air, and the fresh air layer and the internal EGR gas are suppressed in the combustion chamber 104. The EGR stratified combustion can be carried out by stratifying into a stratified fuel, and by mixing the fuel with a large amount of internal EGR and fresh air, the combustion chamber 104 as a whole can greatly reduce the air-fuel ratio and improve fuel efficiency. it can.
However, if the fuel is mixed in the internal EGR gas, the stratification degree decreases, and the amount of internal EGR cannot be increased.
そこで、エンジン制御装置２０１は、内部ＥＧＲガス中に燃料が混じることを抑制するために、第１燃料噴射弁１０６ａによる噴射開始タイミングを、第１吸気ポート１１３ａに吹き返したガスが、第１吸気弁１０５ａを介して燃焼室１０４に吸入された後であって、第１燃料噴射弁１０６ａからの燃料が新気中に噴射されることになるタイミングに設定する。
即ち、ピストンが下降に転じた直後の吸気行程初期には、内部ＥＧＲガスが第１吸気弁１０５ａを介して燃焼室１０４に吸入されるから、このときに第１燃料噴射弁１０６ａによる燃料噴射を行わせると、内部ＥＧＲガス中に燃料を噴射することになり、内部ＥＧＲガスに燃料が混ざって成層度が低下する。
Therefore, the engine control device 201 uses the first intake valve 113a as the gas that has blown back the injection start timing of the first fuel injection valve 106a to the first intake port 113a in order to prevent the fuel from being mixed into the internal EGR gas. It is set to a timing after the fuel from the first fuel injection valve 106a is injected into the fresh air after being sucked into the combustion chamber 104 through 105a.
That is, at the beginning of the intake stroke immediately after the piston starts to descend, the internal EGR gas is sucked into the combustion chamber 104 via the first intake valve 105a. At this time, fuel injection by the first fuel injection valve 106a is performed. When it is performed, fuel is injected into the internal EGR gas, and the fuel is mixed with the internal EGR gas, so that the stratification degree decreases.
このため、第１吸気弁１０５ａを介して内部ＥＧＲが吸入された後の新気の吸入状態で、第１燃料噴射弁１０６ａによる燃料噴射が行われるように、第１燃料噴射弁１０６ａによる燃料噴射を開始させる。
これによって、内部ＥＧＲガス中に燃料が混じることを抑制でき、以って、燃焼室１０４内における新気（混合気）と内部ＥＧＲガスとの成層度が向上するので、第１吸気弁１０５ａの開時期ＩＶＯをより進角させて内部ＥＧＲ量の増大を図ることができ、内部ＥＧＲ量を増大させることで燃費性能を改善できる。
Therefore, the fuel injection by the first fuel injection valve 106a is performed so that the fuel injection by the first fuel injection valve 106a is performed in the fresh air intake state after the internal EGR is sucked through the first intake valve 105a. To start.
As a result, it is possible to prevent the fuel from being mixed into the internal EGR gas, and thus the degree of stratification between the fresh air (air mixture) in the combustion chamber 104 and the internal EGR gas is improved, so that the first intake valve 105a It is possible to increase the internal EGR amount by advancing the opening timing IVO, and to improve the fuel efficiency by increasing the internal EGR amount.
ここで、上死点ＴＤＣから第１燃料噴射弁１０６ａによる噴射開始時期までの遅れ期間は、予め固定値として設定しておくことができるが、第１吸気ポート１１３ａに吹き返したガス量（内部ＥＧＲガス量）が多いほど、吹き返しガスが燃焼室１０４内に吸入されるのに要する時間が長くなり、かつ、吸入空気の流速が遅いほど、吹き返しガスが燃焼室１０４内に吸入されるのに要する時間が長くなる。
このため、吹き返しガス量（内部ＥＧＲ量、吸気通路に導入された燃焼ガスの量）が最も多く、かつ、吸気行程における吸入空気の流速が最も遅い場合であっても、内部ＥＧＲガス中に燃料が混じらないように、上死点ＴＤＣから第１燃料噴射弁１０６ａによる噴射開始時期までの遅れ期間を設定すると、吹き返しガス量が少ないとき及び／又は吸入空気の流速が速いときには、過剰に噴射開始タイミングが遅れ、燃料の気化時間が短くなり、また、燃焼混合気の均質度合いが低下し、燃焼安定性が低下してしまう。
Here, the delay period from the top dead center TDC to the injection start timing by the first fuel injection valve 106a can be set in advance as a fixed value, but the amount of gas blown back to the first intake port 113a (internal EGR). The larger the gas amount), the longer it takes for the blown-back gas to be sucked into the combustion chamber 104, and the slower the intake air flow rate, the more the blown-back gas is taken into the combustion chamber 104. The time will be longer.
For this reason, even when the amount of blown-back gas (internal EGR amount, amount of combustion gas introduced into the intake passage) is the largest and the flow velocity of the intake air in the intake stroke is the slowest, the fuel in the internal EGR gas If a delay period from the top dead center TDC to the injection start timing by the first fuel injection valve 106a is set, the injection starts excessively when the amount of blowback gas is small and / or when the flow rate of the intake air is high The timing is delayed, the fuel vaporization time is shortened, the homogeneity of the combustion mixture is lowered, and the combustion stability is lowered.
そこで、上死点ＴＤＣから第１燃料噴射弁１０６ａの噴射開始時期までの遅れ期間を、吹き返しガス量及び吸入空気の流速に応じて可変に設定することが好ましく、前記遅れ期間の設定処理を、図５のフローチャートに従って説明する。
尚、第２燃料噴射弁１０６ｂが配置される第２吸気ポート１１３ｂへの燃焼ガスの吹き返しは、発生しないか又は無視できる程度に少ないので、内部ＥＧＲに燃料が混じることを抑制するための噴射開始時期の設定は不要であり、第２吸気弁１０５ｂを介して燃焼室１０４内に導入される新気に対して均一に燃料を混合できる最適時期に設定すればよく、第１燃料噴射弁１０６ａの噴射開始時期よりも早い時期（例えば、吸気ＴＤＣ）に燃料噴射を開始させることができる。
Therefore, it is preferable to variably set the delay period from the top dead center TDC to the injection start timing of the first fuel injection valve 106a in accordance with the amount of blowback gas and the flow rate of the intake air. This will be described with reference to the flowchart of FIG.
In addition, since the return of combustion gas to the second intake port 113b where the second fuel injection valve 106b is disposed does not occur or is negligibly small, the start of injection for suppressing fuel from being mixed into the internal EGR It is not necessary to set the timing, and it is only necessary to set the optimal timing at which the fuel can be uniformly mixed with the fresh air introduced into the combustion chamber 104 via the second intake valve 105b. The fuel injection can be started at a time earlier than the injection start time (for example, intake TDC).
図５のフローチャートは、ＥＧＲ成層燃焼時、換言すれば、第１吸気ポート１１３ａに燃焼ガスを導入する運転領域において、エンジン制御装置２０１が一定時間毎に実行する、第１燃料噴射弁１０６ａの噴射開始遅れ時間（噴射開始時期）の設定ルーチンを示す。
まず、ステップＳ１（ガス量検出手段）では、第１吸気ポート１１３ａに対する吹き返しＥＧＲガス量Ｗｍ（cc）の演算を行う。前記吹き返しＥＧＲガス量Ｗｍとは、内部ＥＧＲガス量であり、また、第１吸気ポート１１３ａに導入される燃焼ガスの量である。
The flowchart of FIG. 5 shows the injection of the first fuel injection valve 106a performed by the engine control device 201 at regular intervals in the operation region where the combustion gas is introduced into the first intake port 113a during EGR stratified combustion. The setting routine of a start delay time (injection start time) is shown.
First, in step S1 (gas amount detection means), the blow back EGR gas amount Wm (cc) for the first intake port 113a is calculated. The blow-back EGR gas amount Wm is the amount of internal EGR gas and the amount of combustion gas introduced into the first intake port 113a.
吹き返しＥＧＲガス量Ｗｍの演算は、例えば特開２００４−０４４５４８号公報に開示される推定手段を用いて行うことができる。
具体的には、第１吸気弁１０５ａのバルブ作動角内におけるバルブリフト量と、第１吸気弁１０５ｂの開時期ＩＶＯとに基づき、バルブオーバーラップ時の第１吸気弁１０５ａのバルブ開口面積ＡＷｍを演算し、このバルブ開口面積ＡＷｍに基づいてバルブオーバーラップ時の基本吹き返し量Ｗｍ０を算出する。
The calculation of the blown back EGR gas amount Wm can be performed using, for example, an estimation unit disclosed in Japanese Patent Application Laid-Open No. 2004-045548.
Specifically, based on the valve lift amount within the valve operating angle of the first intake valve 105a and the opening timing IVO of the first intake valve 105b, the valve opening area AWm of the first intake valve 105a at the time of valve overlap is set. Based on this valve opening area AWm, a basic blowback amount Wm0 at the time of valve overlap is calculated.
ここで、バルブ開口面積ＡＷｍが大きいほど、換言すれば、第１吸気弁１０５ａの開時期ＩＶＯが進角しバルブオーバーラップ量が大きくなるほど、また、吸気弁１０５ａのバルブリフト量が大きいほど、基本吹き返し量Ｗｍ０をより大きな値として算出する。
そして、この基本吹き返し量Ｗｍ０に対して、そのときの吸気負圧ＰＢやエンジン回転速度ＮＥに応じた補正を施して、吹き返しＥＧＲガス量Ｗｍを算出する。
前記吸気負圧ＰＢに応じた補正では、第１吸気弁１０５ａの上流側圧力である吸気圧が高いほど（負圧が小さいほど）、吹き返しＥＧＲガス量Ｗｍをより小さく補正する。また、機関回転速度Ｎｅが高いほど吹き返しＥＧＲガス量Ｗｍをより小さく補正する。
Here, as the valve opening area AWm is larger, in other words, as the opening timing IVO of the first intake valve 105a is advanced and the valve overlap amount is larger, and as the valve lift amount of the intake valve 105a is larger, the basic The blowback amount Wm0 is calculated as a larger value.
Then, the basic blowback amount Wm0 is corrected according to the intake negative pressure PB and the engine speed NE at that time to calculate the blowback EGR gas amount Wm.
In the correction according to the intake negative pressure PB, the higher the intake pressure, which is the upstream pressure of the first intake valve 105a (the smaller the negative pressure), the smaller the blow back EGR gas amount Wm is corrected. Further, the higher the engine rotation speed Ne, the smaller the correction of the blow back EGR gas amount Wm.
尚、簡易的には、第１吸気弁１０５ｂの開時期ＩＶＯ（バルブタイミング）が進角するほど、換言すれば、第１吸気弁１０５ｂと排気弁１１０ａ，１１０ｂとのバルブオーバーラップ期間が拡大するほど、吹き返しＥＧＲガス量Ｗｍがより多くなるものとして、吹き返しＥＧＲガス量（内部ＥＧＲガス量）Ｗｍを推定させることができる。 For simplicity, as the opening timing IVO (valve timing) of the first intake valve 105b is advanced, in other words, the valve overlap period between the first intake valve 105b and the exhaust valves 110a and 110b is expanded. As the blow-back EGR gas amount Wm increases, the blow-back EGR gas amount (internal EGR gas amount) Wm can be estimated.
次のステップＳ２（流速検出手段）では、吸気行程において第１吸気ポート１１３ａを流れる吸入空気の流速ＡＳを検出する。
吸入空気の流速ＡＳは、吸気圧センサ１２１が検出した吸気負圧ＰＢや、スロットル開度ＴＶＯとエンジン回転速度ＮＥとの組み合わせや、吸入空気量センサ１０３の出力などから推定することができ、具体的には、高流量側（高負荷側）ほど吸入空気の流速が速いものと推定できる。
In the next step S2 (flow velocity detection means), the flow velocity AS of the intake air flowing through the first intake port 113a in the intake stroke is detected.
The intake air flow rate AS can be estimated from the intake negative pressure PB detected by the intake pressure sensor 121, the combination of the throttle opening TVO and the engine speed NE, the output of the intake air amount sensor 103, and the like. Specifically, it can be estimated that the higher the flow rate side (high load side), the faster the flow rate of the intake air.
ステップＳ３では、ステップＳ１で検出した吹き返しＥＧＲガス量（内部ＥＧＲガス量）Ｗｍと、ステップＳ２で検出した第１吸気ポート１１３ａを流れる吸入空気の流速ＡＳとから、内部ＥＧＲの吸入期間ＴＳを算出する。
内部ＥＧＲの吸入期間ＴＳとは、第１吸気ポート１１３ａに吹き返したＥＧＲガス（内部ＥＧＲガス）が、吸気行程になった後に（吸気ＴＤＣ後に）燃焼室１０４内に吸引されるのに要する時間であり、この吸入期間ＴＳの経過後に新気が燃焼室１０４に吸引されることになる。
In step S3, the intake period TS of the internal EGR is calculated from the blown back EGR gas amount (internal EGR gas amount) Wm detected in step S1 and the flow velocity AS of the intake air flowing through the first intake port 113a detected in step S2. To do.
The intake period TS of the internal EGR is the time required for the EGR gas (internal EGR gas) blown back to the first intake port 113a to be sucked into the combustion chamber 104 after the intake stroke (after the intake TDC). The fresh air is sucked into the combustion chamber 104 after the intake period TS has elapsed.
ここで、内部ＥＧＲの吸入期間ＴＳは、吹き返しＥＧＲガス量（内部ＥＧＲガス量）Ｗｍが多いほど長く、かつ、吸入空気の流速ＡＳが遅いほど長い時間として算出される。
即ち、吸入空気の流速ＡＳが同じであれば、吹き返しＥＧＲガス量（内部ＥＧＲガス量）Ｗｍが多いほど、第１吸気ポート１１３ａ内の内部ＥＧＲガスが燃焼室１０４内に吸引されるのに要する時間が長くなり、また、吹き返しＥＧＲガス量（内部ＥＧＲガス量）Ｗｍが同じであれば、吸入空気の流速ＡＳが遅いほど、第１吸気ポート１１３ａ内の内部ＥＧＲガスが燃焼室１０４内に吸引されるのに要する時間が長くなる。
Here, the intake period TS of the internal EGR is calculated as a longer time as the blow-back EGR gas amount (internal EGR gas amount) Wm is larger and as the intake air flow rate AS is slower.
That is, if the flow rate AS of the intake air is the same, the larger the blow back EGR gas amount (internal EGR gas amount) Wm, the more the internal EGR gas in the first intake port 113a is required to be sucked into the combustion chamber 104. If the time is long and the blowback EGR gas amount (internal EGR gas amount) Wm is the same, the slower the flow rate AS of the intake air, the more the internal EGR gas in the first intake port 113a is sucked into the combustion chamber 104. It takes longer time to be done.
従って、係る特性に基づき、そのときの吹き返しＥＧＲガス量（内部ＥＧＲガス量）Ｗｍ及び吸入空気の流速ＡＳから、内部ＥＧＲの吸入期間ＴＳ、換言すれば、吸気上死点ＴＤＣから内部ＥＧＲガスの燃焼室１０４内への吸引が略完了するまでの時間を推定する。
ステップＳ４（噴射開始時期設定手段）では、ステップＳ３で算出した内部ＥＧＲの吸入期間ＴＳに基づき、第１燃料噴射弁１０６ａの噴射開始時期を設定する。
Therefore, based on such characteristics, from the blow-back EGR gas amount (internal EGR gas amount) Wm and the intake air flow rate AS at that time, the intake period TS of the internal EGR, in other words, from the intake top dead center TDC, The time until the suction into the combustion chamber 104 is almost completed is estimated.
In step S4 (injection start timing setting means), the injection start timing of the first fuel injection valve 106a is set based on the suction period TS of the internal EGR calculated in step S3.
ここで、内部ＥＧＲの吸入期間ＴＳが長いほど、吸気上死点ＴＤＣからより遅れた時期を、第１燃料噴射弁１０６ａの噴射開始時期に設定する。
即ち、第１吸気弁１０５ａ（吸気弁＃１）を通過して燃焼室１０４内に導入されるガスは、図６に示すように、吸気上死点ＴＤＣ直後は内部ＥＧＲガスであり、第１吸気ポート１１３ａに吹き返したＥＧＲガス（内部ＥＧＲガス）が燃焼室１０４内に導入されてから続けて新気が第１吸気弁１０５ａを通過して燃焼室１０４内に導入されることになる。
Here, the longer the intake period TS of the internal EGR, the later the timing from the intake top dead center TDC is set as the injection start timing of the first fuel injection valve 106a.
That is, the gas introduced into the combustion chamber 104 through the first intake valve 105a (intake valve # 1) is internal EGR gas immediately after the intake top dead center TDC, as shown in FIG. After the EGR gas (internal EGR gas) blown back to the intake port 113a is introduced into the combustion chamber 104, fresh air passes through the first intake valve 105a and is introduced into the combustion chamber 104.
そして、第１燃料噴射弁１０６ａから噴射した燃料が内部ＥＧＲガスに混じって成層度が低下することを抑制し、第１燃料噴射弁１０６ａから噴射した燃料を新気と混合させたいので、吹き返しＥＧＲガス量（内部ＥＧＲガス量）の吸入期間ＴＳが略経過してから第１燃料噴射弁１０６ａによる燃料噴射を開始させる。
尚、第１燃料噴射弁１０６ａの噴射開始時期は、第１吸気ポート１１３ａ内の内部ＥＧＲガスの燃焼室１０４への吸引が略完了する時期を含む設定範囲内に設定され、前記設定範囲は、内部ＥＧＲガスへの燃料の混合を抑制して成層度を維持でき、かつ、燃焼室１０４内に吸引された空気に対して燃料を均一に混合させることができる範囲として設定し、前記ステップＳ４における内部ＥＧＲの吸入期間ＴＳから噴射開始時期を設定する特性を予め設定してある。
Then, the fuel injected from the first fuel injection valve 106a is mixed with the internal EGR gas to suppress a decrease in stratification, and the fuel injected from the first fuel injection valve 106a is desired to be mixed with fresh air. The fuel injection by the first fuel injection valve 106a is started after the intake period TS of the gas amount (internal EGR gas amount) substantially elapses.
The injection start timing of the first fuel injection valve 106a is set within a set range including a timing at which the suction of the internal EGR gas in the first intake port 113a to the combustion chamber 104 is substantially completed. In the step S4, a range in which the mixing of the fuel into the internal EGR gas can be suppressed to maintain the stratification degree and the fuel can be uniformly mixed with the air sucked into the combustion chamber 104 is set. A characteristic for setting the injection start timing from the suction period TS of the internal EGR is set in advance.
このようにして、第１燃料噴射弁１０６ａの噴射開始時期を設定すれば、第１吸気弁１０５ａを介し、内部ＥＧＲガスに続けて新気を燃焼室１０４内に導入させても、内部ＥＧＲガスに燃料が混じることを抑制し、かつ、新気に燃料を混ぜることができる。
従って、第２吸気弁１０５ｂを介して燃焼室１０４に新気が導入されると共に、第１吸気弁１０５ａを介しても新気を燃焼室１０４に導入させて、高いエンジントルクを発生させることができ、また、内部ＥＧＲガスに燃料が混じらないので、ＥＧＲ成層燃焼における成層度を確保して、内部ＥＧＲ量の拡大を図れ、燃費性能を改善でき、更に、新気に均一に燃料を混合させて高い燃焼安定性を実現できる。
Thus, if the injection start timing of the first fuel injection valve 106a is set, the internal EGR gas can be introduced even if fresh air is introduced into the combustion chamber 104 following the internal EGR gas via the first intake valve 105a. It is possible to suppress the fuel from being mixed with the fuel and to mix the fuel freshly.
Accordingly, fresh air is introduced into the combustion chamber 104 via the second intake valve 105b, and fresh air is also introduced into the combustion chamber 104 via the first intake valve 105a to generate high engine torque. In addition, since the fuel is not mixed with the internal EGR gas, the stratification degree in the EGR stratified combustion can be secured, the internal EGR amount can be increased, the fuel consumption performance can be improved, and the fuel can be mixed evenly with fresh air. High combustion stability.
また、吹き返しＥＧＲガス量（内部ＥＧＲガス量）Ｗｍが多いほど内部ＥＧＲの吸入期間ＴＳが長くなり、かつ、吸入空気の流速ＡＳが遅いほど内部ＥＧＲの吸入期間ＴＳが長くなることに対応して、第１燃料噴射弁１０６ａによる噴射開始時期を可変に設定するので、吹き返しＥＧＲガス量（内部ＥＧＲガス量）Ｗｍ及び／又は吸入空気の流速が異なっても、第１燃料噴射弁１０６ａによる噴射開始時期が早過ぎて内部ＥＧＲガスに燃料が混ざってしまうことを抑制でき、かつ、第１燃料噴射弁１０６ａによる噴射開始時期が過剰に遅くなって新気における空燃比のばらつきが発生したりすることを抑制できる。 Further, the larger the blowback EGR gas amount (internal EGR gas amount) Wm, the longer the intake period TS of the internal EGR, and the slower the intake air flow rate AS, the longer the intake period TS of the internal EGR. Since the injection start timing by the first fuel injection valve 106a is variably set, the injection by the first fuel injection valve 106a is started even if the blowback EGR gas amount (internal EGR gas amount) Wm and / or the flow velocity of the intake air are different. It is possible to prevent the fuel from being mixed with the internal EGR gas because the timing is too early, and the injection start timing by the first fuel injection valve 106a is excessively delayed, causing variations in the air-fuel ratio in fresh air. Can be suppressed.
尚、簡易には、ステップＳ３において、ステップＳ１で検出した吹き返しＥＧＲガス量（内部ＥＧＲガス量）Ｗｍと、ステップＳ２で検出した第１吸気ポート１１３ａを流れる吸入空気の流速ＡＳとから、第１燃料噴射弁１０６ａによる噴射開始時期を設定させるようにして、内部ＥＧＲの吸入期間ＴＳの算出を省略することができる。
また、図７に示すように、燃料噴射弁１０６として、第１吸気ポート１１３ａ（第１吸気弁１０５ａ）に向けて燃料を噴射すると共に、第２吸気ポート１１３ｂ（第２吸気弁１０５ｂ）に向けても燃料を噴射する２方向噴射弁を１つ備える場合には、ステップＳ４で設定した噴射開始時期で燃料噴射を開始させるようにすればよく、上記の２方向噴射弁を各気筒に１つ備えるエンジン１０１にも、上記の噴射開始時期の設定処理を適用できる。
また、第１燃料噴射弁１０６ａによる燃料噴射量と、第２燃料噴射弁１０６ｂによる燃料噴射量との比率を、各吸気弁１０５ａ，１０５ｂを介して燃焼室１０４に導入される新気の比率に合わせることで、混合気における空燃比ばらつきを抑制できる。
For simplicity, in step S3, a first EGR gas amount (internal EGR gas amount) Wm detected in step S1 and a flow velocity AS of the intake air flowing through the first intake port 113a detected in step S2 are calculated as follows. Calculation of the intake period TS of the internal EGR can be omitted by setting the injection start timing by the fuel injection valve 106a.
In addition, as shown in FIG. 7, as the fuel injection valve 106, fuel is injected toward the first intake port 113a (first intake valve 105a) and toward the second intake port 113b (second intake valve 105b). However, when one two-way injection valve for injecting fuel is provided, the fuel injection may be started at the injection start timing set in step S4. One two-way injection valve is provided for each cylinder. The above-described injection start time setting process can also be applied to the engine 101 provided.
Further, the ratio of the fuel injection amount by the first fuel injection valve 106a and the fuel injection amount by the second fuel injection valve 106b is set to the ratio of fresh air introduced into the combustion chamber 104 via the intake valves 105a and 105b. By combining, air-fuel ratio variation in the air-fuel mixture can be suppressed.
ところで、上記実施形態は、燃焼ガスが燃焼室１０４から第１吸気ポート１１３ａ内に吹き返す内部ＥＧＲを行わせることで、第１吸気ポート１１３ａに対して燃焼ガスを導入させるようにしたが、図８に示すように、第１燃料噴射弁１０６ａ下流側の第１吸気ポート１１３ａと排気管１１１とを連通させる排気還流通路１２２（燃焼ガス導入手段）と、該排気還流通路１２２に介装され排気還流量（外部ＥＧＲガス量）を制御する排気還流弁（電磁バルブ）１２３とを備え、排気管１１１から燃焼ガスを第１吸気ポート１１３ａに還流（導入）させる外部ＥＧＲを行うエンジン１０１においても、外部ＥＧＲガス量と吸入空気の流速ＡＳとから、第１燃料噴射弁１０６ａによる噴射開始時期を設定することにより、上記実施形態と同様な作用効果を得ることができる。 Incidentally, in the above embodiment, the combustion gas is introduced into the first intake port 113a by performing the internal EGR in which the combustion gas blows back from the combustion chamber 104 into the first intake port 113a. As shown in FIG. 3, an exhaust gas recirculation passage 122 (combustion gas introduction means) for communicating the first intake port 113a downstream of the first fuel injection valve 106a and the exhaust pipe 111, and an exhaust gas return passage interposed in the exhaust gas recirculation passage 122. An engine 101 that includes an exhaust recirculation valve (electromagnetic valve) 123 that controls the flow rate (external EGR gas amount) and performs external EGR that recirculates (introduces) combustion gas from the exhaust pipe 111 to the first intake port 113a. By setting the injection start timing by the first fuel injection valve 106a from the EGR gas amount and the flow velocity AS of the intake air, the same operation as in the above embodiment is performed. Effect can be obtained.
尚、上記の外部ＥＧＲを行うエンジン１０１の場合、吸気弁１０５ａ，１０５ｂの開時期ＩＶＯの設定によって吹き返しガス（内部ＥＧＲ）を第１吸気ポート１１３ａに導入する必要はないので、吸気弁１０５ａ，１０５ｂのバルブタイミングを同じに揃えることができる。
図９のフローチャートは、図８に示した構造によって外部ＥＧＲを行うエンジン１０１において、エンジン制御装置２０１が実施する第１燃料噴射弁１０６ａの噴射開始時期の設定処理を示す。
In the case of the engine 101 that performs the above external EGR, it is not necessary to introduce the blow back gas (internal EGR) into the first intake port 113a by setting the opening timing IVO of the intake valves 105a and 105b. The valve timing can be made the same.
The flowchart of FIG. 9 shows the setting process of the injection start timing of the first fuel injection valve 106a performed by the engine control device 201 in the engine 101 that performs external EGR with the structure shown in FIG.
図９のフローチャートに示すルーチンは、エンジン制御装置２０１によって一定時間毎に実施され、まず、ステップＳ２１（ガス量検出手段）では、排気還流通路１２２を介して第１吸気ポート１１３ａ内に導入される外部ＥＧＲ量Ｗｍ１（第１吸気ポート１１３ａ内に導入される燃焼ガス量）を算出する。
前記外部ＥＧＲ量Ｗｍ１の算出は、排気管１１１内の圧力と、吸気管１０２内の圧力ＰＢとの差圧に基づいて行われる。即ち、外部ＥＧＲは、前記差圧に基づき排気管１１１内の燃焼ガスを吸気管１０２内に還流させるものであり、差圧が大きいほど、換言すれば、排気管１１１内の圧力よりも吸気管１０２内の圧力ＰＢが低いほど、還流される燃焼ガスの量が増えることになる。
The routine shown in the flowchart of FIG. 9 is executed at regular intervals by the engine control apparatus 201. First, in step S21 (gas amount detection means), the routine is introduced into the first intake port 113a via the exhaust gas recirculation passage 122. The external EGR amount Wm1 (the amount of combustion gas introduced into the first intake port 113a) is calculated.
The calculation of the external EGR amount Wm1 is performed based on the differential pressure between the pressure in the exhaust pipe 111 and the pressure PB in the intake pipe 102. That is, the external EGR recirculates the combustion gas in the exhaust pipe 111 into the intake pipe 102 based on the differential pressure. The larger the differential pressure, in other words, the intake pipe than the pressure in the exhaust pipe 111. The lower the pressure PB in 102, the greater the amount of combustion gas that is recirculated.
そこで、ステップＳ２１では、排気管１１１内の圧力と、吸気管１０２内の圧力ＰＢとの差圧が大きいほど、外部ＥＧＲ量Ｗｍ１が多いと推定する。
ここで、吸気管１０２内の圧力ＰＢは、吸気圧センサ１２１の出力から検出できる他、吸気圧センサ１２１を備えないエンジン１０１では、スロットル開度ＴＶＯとエンジン回転速度ＮＥとから推定できる。
Therefore, in step S21, it is estimated that the external EGR amount Wm1 increases as the differential pressure between the pressure in the exhaust pipe 111 and the pressure PB in the intake pipe 102 increases.
Here, the pressure PB in the intake pipe 102 can be detected from the output of the intake pressure sensor 121, and can be estimated from the throttle opening TVO and the engine rotational speed NE in the engine 101 that does not include the intake pressure sensor 121.
また、排気管１１１内の圧力は、スロットル開度ＴＶＯとエンジン回転速度ＮＥとに基づき推定できる他、圧力センサで検出させることができる。
また、吸気管１０２内の圧力及び排気管１１１内の圧力は、共にスロットル開度ＴＶＯとエンジン回転速度ＮＥとに基づき推定できるから、スロットル開度ＴＶＯとエンジン回転速度ＮＥとから差圧を推定することができる。
Further, the pressure in the exhaust pipe 111 can be estimated based on the throttle opening TVO and the engine rotational speed NE, and can be detected by a pressure sensor.
Further, since the pressure in the intake pipe 102 and the pressure in the exhaust pipe 111 can both be estimated based on the throttle opening TVO and the engine rotational speed NE, the differential pressure is estimated from the throttle opening TVO and the engine rotational speed NE. be able to.
尚、排気還流弁（電磁バルブ）１２３が開又は閉に制御される場合は、上記のように、開状態での排気還流弁（電磁バルブ）１２３の前後差圧から、外部ＥＧＲ量Ｗｍ１を推定できるが、排気還流弁（電磁バルブ）１２３の開度を変化させて、外部ＥＧＲ量Ｗｍ１を調整する場合には、排気還流弁（電磁バルブ）１２３の開度と前記差圧とから、外部ＥＧＲ量Ｗｍ１を推定できる。
また、吸気弁１０５ａ，１０５ｂのバルブタイミングが可変動弁機構１１４ａ，１１４ｂによって可変とされる場合、バルブタイミング（開時期ＩＶＯ）が進角され、バルブオーバーラップ期間が拡大すると、内部ＥＧＲ量が増えるので、バルブタイミングが進角されるほど、外部ＥＧＲ量Ｗｍ１を増大補正し、内部ＥＧＲ量の含むガス量として外部ＥＧＲ量Ｗｍ１を算出させてもよい。
When the exhaust recirculation valve (electromagnetic valve) 123 is controlled to be opened or closed, the external EGR amount Wm1 is estimated from the differential pressure across the exhaust recirculation valve (electromagnetic valve) 123 in the open state as described above. However, when adjusting the external EGR amount Wm1 by changing the opening degree of the exhaust gas recirculation valve (electromagnetic valve) 123, the external EGR value is determined from the opening degree of the exhaust gas recirculation valve (electromagnetic valve) 123 and the differential pressure. The amount Wm1 can be estimated.
Further, when the valve timings of the intake valves 105a and 105b are made variable by the variable valve mechanisms 114a and 114b, the valve timing (open timing IVO) is advanced and the valve overlap period increases, so that the internal EGR amount increases. Therefore, the external EGR amount Wm1 may be corrected to increase as the valve timing is advanced, and the external EGR amount Wm1 may be calculated as the gas amount included in the internal EGR amount.
また、外部ＥＧＲ量Ｗｍ１をバルブタイミング（バルブオーバーラップ期間）に応じて補正する代わりに、バルブタイミングの進角に伴う内部ＥＧＲ量の増大に応じて、後述する吸入期間ＴＳ１を増大補正したり、噴射開始時期をより遅い時期に補正したりすることができる。 Further, instead of correcting the external EGR amount Wm1 according to the valve timing (valve overlap period), an intake period TS1 described later is increased and corrected according to the increase in the internal EGR amount accompanying the advance of the valve timing, The injection start time can be corrected to a later time.
次のステップＳ２２（流速検出手段）では、前記ステップＳ２と同様にして、吸気行程において第１吸気ポート１１３ａを流れる吸入空気の流速ＡＳを検出する。
そして、ステップＳ２３では、ステップＳ２１で検出した外部ＥＧＲ量Ｗｍ１と、ステップＳ２２で検出した第１吸気ポート１１３ａを流れる吸入空気の流速ＡＳとから、外部ＥＧＲの吸入期間ＴＳ１を算出する。
In the next step S22 (flow velocity detection means), the flow velocity AS of the intake air flowing through the first intake port 113a in the intake stroke is detected in the same manner as in step S2.
In step S23, the external EGR intake period TS1 is calculated from the external EGR amount Wm1 detected in step S21 and the intake air flow velocity AS flowing in the first intake port 113a detected in step S22.
外部ＥＧＲによって第１吸気ポート１１３ａ内に燃焼ガスを導入する場合、吸気上死点ＴＤＣから吸気下死点ＢＤＣに向けて徐々に第１吸気ポート１１３ａ内の圧力は上昇し、排気管１１１内の圧力と吸気管１０２内の圧力ＰＢとの差圧は徐々に小さくなる。
このため、図１０に示すように、第１吸気弁１０５ａを介して燃焼室１０４内に導入されるガスは、吸気行程の当初は外部ＥＧＲがその殆ど占めるが、その後は、外部ＥＧＲが占める割合が徐々に小さくなり、相対的に新気が占める割合が高くなる。
ここで、外部ＥＧＲの吸入期間ＴＳ１としては、例えば、吸気上死点ＴＤＣから、燃焼室１０４内に導入されるガスのうち外部ＥＧＲが占める割合が減少に転じるまでの期間として算出させる。そして、外部ＥＧＲの吸入期間ＴＳ１を、外部ＥＧＲ量Ｗｍ１が多いほど長く、かつ、吸入空気の流速ＡＳが遅いほど長い期間として算出する。
When the combustion gas is introduced into the first intake port 113a by the external EGR, the pressure in the first intake port 113a gradually increases from the intake top dead center TDC toward the intake bottom dead center BDC. The differential pressure between the pressure and the pressure PB in the intake pipe 102 gradually decreases.
For this reason, as shown in FIG. 10, the gas introduced into the combustion chamber 104 via the first intake valve 105a is mostly occupied by the external EGR at the beginning of the intake stroke, but thereafter the ratio occupied by the external EGR. Will gradually become smaller and the proportion of fresh air will be relatively higher.
Here, the intake period TS1 of the external EGR is calculated as, for example, a period from the intake top dead center TDC until the ratio occupied by the external EGR in the gas introduced into the combustion chamber 104 starts to decrease. Then, the external EGR intake period TS1 is calculated as a longer period as the external EGR amount Wm1 increases and as the intake air flow rate AS decreases.
ステップＳ２４（噴射開始時期設定手段）では、ステップＳ２３で算出した外部ＥＧＲの吸入期間ＴＳ１に基づき、第１燃料噴射弁１０６ａの噴射開始時期を設定する。
ここで、外部ＥＧＲの吸入期間ＴＳ１が長いほど、吸気上死点ＴＤＣからより遅れた時期を、第１燃料噴射弁１０６ａの噴射開始時期に設定する。
In step S24 (injection start timing setting means), the injection start timing of the first fuel injection valve 106a is set based on the suction period TS1 of the external EGR calculated in step S23.
Here, the longer the intake period TS1 of the external EGR, the later the time from the intake top dead center TDC is set as the injection start timing of the first fuel injection valve 106a.
このようにして、第１燃料噴射弁１０６ａの噴射開始時期を設定すれば、第１吸気弁１０５ａを介し、外部ＥＧＲガスに続けて新気を燃焼室１０４内に導入させても、外部ＥＧＲガスの燃焼室１０４への導入量が減り始めてから第１燃料噴射弁１０６ａによる燃料噴射を開始させるので、外部ＥＧＲガスに燃料が混じることを抑制し、新気に燃料を混ぜることができる。
従って、第２吸気弁１０５ｂを介して燃焼室１０４に新気が導入されると共に、第１吸気弁１０５ａを介しても新気を燃焼室１０４に導入させて、高いエンジントルクを発生させることができ、また、外部ＥＧＲガスに燃料が混じらないので、ＥＧＲ成層燃焼における成層度を確保して、外部ＥＧＲ量の拡大を図れ、燃費性能を改善でき、更に、新気に均一に燃料を混合させて高い燃焼安定性を実現できる。
Thus, if the injection start timing of the first fuel injection valve 106a is set, the external EGR gas can be introduced even if fresh air is introduced into the combustion chamber 104 following the external EGR gas via the first intake valve 105a. Since the fuel injection by the first fuel injection valve 106a is started after the amount introduced into the combustion chamber 104 starts to decrease, it is possible to suppress the mixing of fuel with the external EGR gas and to mix the fuel with fresh air.
Accordingly, fresh air is introduced into the combustion chamber 104 via the second intake valve 105b, and fresh air is also introduced into the combustion chamber 104 via the first intake valve 105a to generate high engine torque. In addition, since the fuel is not mixed with the external EGR gas, the stratification degree in the EGR stratified combustion can be secured, the external EGR amount can be increased, the fuel consumption performance can be improved, and the fuel can be mixed evenly with fresh air. High combustion stability.
また、外部ＥＧＲガス量Ｗｍ１が多いほど外部ＥＧＲの吸入期間ＴＳ１が長くなり、かつ、吸入空気の流速ＡＳが遅いほど外部ＥＧＲの吸入期間ＴＳ１が長くなることに対応して、第１燃料噴射弁１０６ａによる噴射開始時期を可変に設定するので、外部ＥＧＲガス量Ｗｍ１及び／又は吸入空気の流速ＡＳが異なっても、第１燃料噴射弁１０６ａによる噴射開始時期が早過ぎて外部ＥＧＲガスに燃料が混ざってしまうことを抑制でき、かつ、第１燃料噴射弁１０６ａによる噴射開始時期が過剰に遅くなって新気における空燃比のばらつきが発生したりすることを抑制できる。 Further, the first fuel injection valve corresponds to the fact that the external EGR intake period TS1 is longer as the external EGR gas amount Wm1 is larger, and the external EGR intake period TS1 is longer as the intake air flow rate AS is slower. Since the injection start timing by 106a is variably set, even if the external EGR gas amount Wm1 and / or the flow velocity AS of the intake air are different, the injection start timing by the first fuel injection valve 106a is too early and fuel is supplied to the external EGR gas. Mixing can be suppressed, and the occurrence of variations in the air-fuel ratio in fresh air due to the excessive delay in the injection start timing of the first fuel injection valve 106a can be suppressed.
尚、簡易には、ステップＳ２３において、ステップＳ２１で検出した外部ＥＧＲガス量Ｗｍ１と、ステップＳ２２で検出した第１吸気ポート１１３ａを流れる吸入空気の流速ＡＳとから、第１燃料噴射弁１０６ａによる噴射開始時期を設定させるようにして、外部ＥＧＲの吸入期間ＴＳ１の算出を省略することができる。
また、燃料噴射弁１０６として、第１吸気ポート１１３ａ（第１吸気弁１０５ａ）に向けて燃料を噴射すると共に、第２吸気ポート１１３ｂ（第２吸気弁１０５ｂ）に向けても燃料を噴射する２方向噴射弁を１つ備える場合には、ステップＳ２４で設定した噴射開始時期で燃料噴射を開始させるようにすればよく、上記の２方向噴射弁を各気筒に１つ備えかつ外部ＥＧＲが行われるエンジン１０１にも、上記の噴射開始時期の設定処理を適用できる。
For simplicity, in step S23, the injection by the first fuel injection valve 106a is performed from the external EGR gas amount Wm1 detected in step S21 and the flow velocity AS of the intake air flowing through the first intake port 113a detected in step S22. The calculation of the inhalation period TS1 of the external EGR can be omitted by setting the start time.
The fuel injection valve 106 injects fuel toward the first intake port 113a (first intake valve 105a) and also injects fuel toward the second intake port 113b (second intake valve 105b) 2. When one directional injection valve is provided, it is only necessary to start fuel injection at the injection start timing set in step S24. One directional injection valve is provided for each cylinder, and external EGR is performed. The above-described injection start time setting process can also be applied to the engine 101.
ところで、外部ＥＧＲを行う場合、図１０に示したように、外部ＥＧＲ量は吸気行程中に徐々に低下し、新気が導入されるようになってからも新気と共に外部ＥＧＲガスが、第１吸気弁１０５ａを通過することになる。
従って、第１燃料噴射弁１０６ａから噴射される燃料噴霧の貫徹力が強いと、噴射開始時期を新気の吸引開始後に設定しても、排気還流通路１２２を介して第１吸気ポート１１３ａ内に導入された外部ＥＧＲガスにまで燃料噴霧が到達し、燃料が外部ＥＧＲに混じる可能性が高まってしまう。
By the way, when external EGR is performed, as shown in FIG. 10, the external EGR amount gradually decreases during the intake stroke, and even after fresh air is introduced, the external EGR gas is changed along with the fresh air. One intake valve 105a is passed.
Therefore, if the penetration force of the fuel spray injected from the first fuel injection valve 106a is strong, even if the injection start timing is set after the start of suction of fresh air, it will enter the first intake port 113a via the exhaust gas recirculation passage 122. The fuel spray reaches the introduced external EGR gas, and the possibility that the fuel is mixed with the external EGR increases.
そこで、外部ＥＧＲを行うエンジン１０１においては、排気還流通路１２２が合流する箇所よりも手前の第１吸気ポート１１３ａ内に存在している新気に対し、第１燃料噴射弁１０６ａが噴射した燃料が混じるように、換言すれば、第１燃料噴射弁１０６ａの燃料噴霧が、排気還流通路１２２が合流する箇所の下流側まで到達することを抑制できるように、第１燃料噴射弁１０６ａの燃料噴霧の貫徹力を弱くすることが好ましい。
貫徹力を弱くする手段としては、第１燃料噴射弁１０６ａから噴射される燃料噴霧の粒径を小さくする手段の他、図１１に示すように、第１燃料噴射弁１０６ａからの燃料噴射を複数回に分割して行わせることで、１回当たりの噴射時間を短くする手段（分割噴射制御手段）を用いることができる。
Therefore, in the engine 101 that performs the external EGR, the fuel injected by the first fuel injection valve 106a against the fresh air existing in the first intake port 113a before the location where the exhaust gas recirculation passage 122 joins is generated. In other words, in other words, the fuel spray of the first fuel injection valve 106a can be suppressed so that the fuel spray of the first fuel injection valve 106a reaches the downstream side of the location where the exhaust gas recirculation passage 122 joins. It is preferable to reduce the penetration force.
As means for weakening the penetration force, in addition to means for reducing the particle size of the fuel spray injected from the first fuel injection valve 106a, a plurality of fuel injections from the first fuel injection valve 106a are performed as shown in FIG. By performing the process dividedly, it is possible to use means for dividing the injection time per time (divided injection control means).
第１燃料噴射弁１０６ａによる噴射を複数回に分けて行い、１回当たりの噴射時間を短くすれば、燃料噴霧の貫徹力が弱まり、排気還流通路１２２の合流点以降まで燃料噴霧が到達することを抑制でき、排気還流通路１２２の合流点よりも手前の新気に燃料を混ぜることができ、以って、外部ＥＧＲガスに燃料が混じることを抑制できる。
ここで、燃料噴射の分割回数を多くして、１回当たりの噴射時間をより短くすれば、燃料噴霧の貫徹力が弱くなるが、燃料噴射の分割回数を多くするほど、噴射終了時点から次の噴射を開始するまでの間隔時間の総和が長くなり、同じ燃料噴射量に対して最終的に燃料噴射を終えるまでの時間が長くなる。
If the injection by the first fuel injection valve 106a is divided into a plurality of times and the injection time per time is shortened, the penetration force of the fuel spray is weakened, and the fuel spray reaches after the confluence of the exhaust gas recirculation passage 122. The fuel can be mixed with the fresh air before the junction of the exhaust gas recirculation passage 122, so that the fuel can be suppressed from mixing with the external EGR gas.
Here, if the number of divisions of fuel injection is increased and the injection time per one is shortened, the penetration force of fuel spray becomes weaker. However, as the number of divisions of fuel injection is increased, The sum of the interval time until the start of injection becomes longer, and the time until fuel injection is finally finished for the same fuel injection amount becomes longer.
従って、吸気弁１０５ａの開弁時間、換言すれば、燃料噴射の可能時間の長短に応じて分割回数を設定することが好ましい。例えば、図１２に示すように、吸気弁１０５ａの開弁時間が長いほど、分割回数を多く設定し、設定した分割回数で、燃料噴射パルス幅ＴＩを除算して、１回当たりの噴射パルス幅を決定し、初回の噴射開始時期を、前述の外部ＥＧＲガス量Ｗｍ１及び吸入空気の流速ＡＳに応じて決定した噴射開始時期として、初回の噴射が終了した一定時間後に２回目の噴射を開始させ、最終的には、設定した分割回数だけ噴射を繰り返すようにする。
吸気弁１０５ａの開弁時間は、吸気弁１０５ａの作動角とそのときのエンジン回転速度ＮＥから求めることができる。
Therefore, it is preferable to set the number of divisions in accordance with the valve opening time of the intake valve 105a, in other words, the length of the fuel injection possible time. For example, as shown in FIG. 12, the longer the valve opening time of the intake valve 105a, the greater the number of divisions, and the fuel injection pulse width TI is divided by the set number of divisions to inject the injection pulse width per time. The first injection start timing is set as the injection start timing determined according to the external EGR gas amount Wm1 and the intake air flow rate AS described above, and the second injection is started after a certain time after the first injection is completed. Finally, the injection is repeated for the set number of divisions.
The valve opening time of the intake valve 105a can be obtained from the operating angle of the intake valve 105a and the engine speed NE at that time.
また、第１吸気弁１０５ａを通過して燃焼室１０４内に吸引される外部ＥＧＲガスの量は吸気行程中に徐々に低下するから、吸気行程の後半ほど（吸気下死点ＢＤＣに近づくほど）、燃料噴霧の貫徹力が強くなっても、外部ＥＧＲに対して燃料が混じることを抑制でき、また、分割各回の噴射パルス幅（１回当たりの噴射量）をなるべく大きくすれば、新気吸入中に燃料噴射していない期間が減って、新気に対して燃料を均一に混合させることができる。
そこで、分割噴射においては、各回の噴射パルス幅を均一にするのではなく、図１３に示すように、噴射回数の増加に対して噴射パルス幅（燃料噴射量）を増大変化させることが好ましい。ここで、噴射回数が増える毎に、前回よりも噴射パルス幅を増大させても良いし、例えば、２回目以降の噴射における噴射パルス幅を同じに設定し、係る２回目以降の噴射における噴射パルス幅を、１回目の噴射における噴射パルス幅よりも長くすることができる。
Further, the amount of the external EGR gas that passes through the first intake valve 105a and is sucked into the combustion chamber 104 gradually decreases during the intake stroke, so that the latter half of the intake stroke (as it approaches the intake bottom dead center BDC). Even if the penetration force of the fuel spray becomes strong, it is possible to suppress the mixing of fuel with the external EGR, and if the divided injection pulse width (injection amount per one time) is made as large as possible, fresh air intake The period during which the fuel is not injected is reduced, and the fuel can be uniformly mixed with the fresh air.
Therefore, in divided injection, it is preferable that the injection pulse width (fuel injection amount) is increased and changed as the number of injections increases, as shown in FIG. Here, each time the number of injections increases, the injection pulse width may be increased from the previous time. For example, the injection pulse width in the second and subsequent injections is set to be the same, and the injection pulse in the second and subsequent injections is set. The width can be longer than the injection pulse width in the first injection.
ここで、上記実施形態から把握し得る請求項以外の技術的思想について、以下に効果と共に記載する。
（イ）請求項１〜３のいずれか１つに記載の内燃機関の制御装置において、
前記吸気通路として、気筒毎に第１吸気弁を備えた第１吸気ポートと第２吸気弁を備えた第２吸気ポートとを備え、
前記燃料噴射弁として、前記第１吸気ポート内に燃料を噴射する第１燃料噴射弁と、前記第２吸気ポート内に燃料を噴射する第２燃料噴射弁とを備え、
前記燃焼ガス導入手段が、前記第１吸気弁をピストン上昇中に開弁させる一方、前記第２吸気弁をピストン上死点以降に開弁させることで、燃焼室内の燃焼ガスを前記第１吸気ポート内に導入させ、
前記噴射開始時期設定手段は、前記第１吸気ポート内に導入された燃焼ガスが前記第１吸気弁を介して燃焼室内に導入された後の新気導入開始時期に応じて、前記第１燃料噴射弁の噴射開始時期を設定する内燃機関の制御装置。
Here, technical ideas other than the claims that can be grasped from the above embodiment will be described together with effects.
(A) In the control device for an internal combustion engine according to any one of claims 1 to 3,
The intake passage includes a first intake port provided with a first intake valve for each cylinder and a second intake port provided with a second intake valve;
The fuel injection valve includes a first fuel injection valve that injects fuel into the first intake port, and a second fuel injection valve that injects fuel into the second intake port,
The combustion gas introduction means opens the first intake valve while the piston is raised, and opens the second intake valve after the piston top dead center, so that the combustion gas in the combustion chamber is opened to the first intake valve. In the port,
The injection start timing setting means is configured to change the first fuel in accordance with a fresh air introduction start timing after the combustion gas introduced into the first intake port is introduced into the combustion chamber via the first intake valve. A control device for an internal combustion engine that sets an injection start timing of an injection valve.
係る構成では、第１吸気ポートから、燃焼ガス（内部ＥＧＲガス）の導入に続けて新気を燃焼室内に導入するので、第１吸気ポートと第２吸気ポートとから並行してガスを燃焼室内に導入することができ、燃焼室内におけるスワールの形成を抑制でき、ＥＧＲ成層燃焼を可能にでき、かつ、内部ＥＧＲガスに燃料が混じることを抑制して成層度を向上させることができるので、ＥＧＲ量の増量によって燃費性能を改善できる。 In such a configuration, since fresh air is introduced into the combustion chamber from the first intake port following the introduction of the combustion gas (internal EGR gas), gas is introduced into the combustion chamber in parallel from the first intake port and the second intake port. EGR can be suppressed, swirl formation in the combustion chamber can be suppressed, EGR stratified combustion can be performed, and mixing of fuel with the internal EGR gas can be suppressed to improve the stratification degree. Fuel consumption performance can be improved by increasing the amount.
（ロ）請求項３記載の内燃機関の制御装置において、
前記分割噴射制御手段は、噴射回数の増加に対して１回当たりの燃料噴射量を増大させる内燃機関の制御装置。
係る構成では、噴射開始当初の新気比率が小さいときは、噴射量の抑制によって燃料噴霧の貫徹力を弱め、外部ＥＧＲに対して燃料が混じることを抑制し、新気比率の増大に応じて噴射量（噴射パルス幅）を増大させて、新気に対する燃料の混合性を改善して、高い燃焼性を実現できる。
(B) In the control device for an internal combustion engine according to claim 3,
The split injection control means is a control device for an internal combustion engine that increases a fuel injection amount per time as the number of injections increases.
In such a configuration, when the fresh air ratio at the beginning of injection is small, the penetration amount of the fuel spray is weakened by suppressing the injection amount, the fuel is prevented from being mixed with the external EGR, and the fresh air ratio is increased. High combustibility can be realized by increasing the injection amount (injection pulse width) and improving the mixing of fuel with fresh air.
１０１…エンジン（内燃機関）、１０５ａ，１０５ｂ…吸気弁、１０６ａ，１０６ｂ…燃料噴射弁、１０７…点火プラグ、１０９…クランクシャフト、１１０ａ，１１０ｂ…排気弁、１１３ａ，１１３ｂ…吸気ポート、１１４ａ，１１４ｂ…可変動弁機構、１１５…点火モジュール、２０１…エンジン制御装置、２０３…クランク角センサ、２０４…カム角センサ DESCRIPTION OF SYMBOLS 101 ... Engine (internal combustion engine), 105a, 105b ... Intake valve, 106a, 106b ... Fuel injection valve, 107 ... Spark plug, 109 ... Crankshaft, 110a, 110b ... Exhaust valve, 113a, 113b ... Intake port, 114a, 114b ... Variable valve mechanism, 115 ... Ignition module, 201 ... Engine control device, 203 ... Crank angle sensor, 204 ... Cam angle sensor
Claims (3)
前記吸気通路内に燃焼ガスを導入する燃焼ガス導入手段と、
前記燃焼ガス導入手段によって前記吸気通路内に導入される燃焼ガス量を検出するガス量検出手段と、
前記吸気通路内を流れる吸入空気の流速を検出する流速検出手段と、
前記吸気通路内に導入される燃焼ガス量が多いほど前記燃料噴射弁による噴射開始時期をより遅い時期に設定し、かつ、前記吸入空気の流速が遅いほど前記噴射開始時期をより遅い時期に設定する噴射開始時期設定手段と、
を含む内燃機関の制御装置。 A control device for an internal combustion engine including a fuel injection valve for injecting fuel into an intake passage,
Combustion gas introduction means for introducing combustion gas into the intake passage;
A gas amount detecting means for detecting a combustion gas amount introduced into the intake passage by the combustion gas introducing means;
A flow velocity detecting means for detecting a flow velocity of the intake air flowing in the intake passage;
As the amount of combustion gas introduced into the intake passage increases, the injection start timing by the fuel injection valve is set to a later timing, and as the flow rate of the intake air is slower, the injection start timing is set to a later timing. Injection start time setting means to perform,
A control device for an internal combustion engine, including:
前記ガス量検出手段が、前記バルブオーバーラップ期間が増加するほど前記吸気通路内に導入される燃焼ガス量をより多く検出することで、前記噴射開始時期設定手段が、前記バルブオーバーラップ期間が増加するほど前記噴射開始時期をより遅い時期に設定する請求項１記載の内燃機関の制御装置。 The combustion gas introduction means variably controls a valve overlap period between the intake valve and the exhaust valve to control the amount of combustion gas introduced into the intake passage;
The gas amount detection means detects a larger amount of combustion gas introduced into the intake passage as the valve overlap period increases, so that the injection start timing setting means increases the valve overlap period. 2. The control apparatus for an internal combustion engine according to claim 1, wherein the injection start timing is set to a later timing as the operation is performed.
前記噴射開始時期設定手段が設定した噴射開始時期での噴射を初回として、前記燃料噴射弁による噴射を複数回に分割して行わせる分割噴射制御手段を設けた請求項１又は２記載の内燃機関の制御装置。 The combustion gas introduction means is external EGR means for recirculating combustion gas from an exhaust passage into an intake passage downstream of the fuel injection valve;
The internal combustion engine according to claim 1 or 2, further comprising split injection control means for performing injection by the fuel injection valve in a plurality of times, with the injection at the injection start time set by the injection start time setting means being the first time. Control device.
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| WO2019202883A1 (en) * | 2018-04-19 | 2019-10-24 | 日立オートモティブシステムズ株式会社 | Fuel injection control device and fuel injection control method for internal combustion engine |
| JP2019190289A (en) * | 2018-04-19 | 2019-10-31 | 日立オートモティブシステムズ株式会社 | Fuel injection control device of internal combustion engine |
| US11078861B2 (en) | 2018-04-19 | 2021-08-03 | Hitachi Astemo, Ltd. | Fuel injection control device and fuel injection control method for internal combustion engine |
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