JP2021059998A - Control device of internal combustion engine - Google Patents

Control device of internal combustion engine Download PDF

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JP2021059998A
JP2021059998A JP2019183840A JP2019183840A JP2021059998A JP 2021059998 A JP2021059998 A JP 2021059998A JP 2019183840 A JP2019183840 A JP 2019183840A JP 2019183840 A JP2019183840 A JP 2019183840A JP 2021059998 A JP2021059998 A JP 2021059998A
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correction value
exhaust gas
pressure
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JP7414451B2 (en
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優真 佃
Yuma Tsukuda
優真 佃
裕一 外山
Yuichi Toyama
裕一 外山
高田　健司
Kenji Takada
健司 高田
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Hitachi Astemo Ltd
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Abstract

To provide a control device, of an internal combustion engine mounted with an EGR system, capable of improving exhaust performance and combustion in a transient state.SOLUTION: A control device according to the present invention obtains: partial pressure of air in an intake pipe downstream of a throttle valve on the basis of a volume of air passing through the throttle valve, a flow rate of fresh air flowing into a cylinder, and a first pressure gradient correction value; partial pressure of reflux exhaust gas in the intake pipe on the basis of a flux volume of exhaust gas, a flow rate of the exhaust gas flowing into the cylinder and a second pressure gradient correction value; intake pipe pressure on the basis of the partial pressure of the air and the partial pressure of reflux exhaust gas; the volume of air passing through the throttle valve on the basis of the intake pipe pressure; and the flow rate of the fresh air flowing into the cylinder on the basis of the partial pressure of air. Then, the control device calculates a fuel injection amount with a fuel injection device on the basis of the flow rate of the fresh air flowing into the cylinder.SELECTED DRAWING: Figure 2

Description

本発明は、燃焼後の排ガスをスロットル弁の下流の吸気管に還流させるＥＧＲ（Exhaust Gas Recirculation）システムを備えた内燃機関の制御装置に関する。 The present invention relates to a control device for an internal combustion engine provided with an EGR (Exhaust Gas Recirculation) system for returning exhaust gas after combustion to an intake pipe downstream of a throttle valve.

特許文献１に開示される筒内流入ＥＧＲガス流量推定装置は、吸気弁モデルを用いて筒内流入総ガス流量を演算する手段と、ＥＧＲ弁モデルを用いてＥＧＲ弁通過ガス流量を演算する手段と、ＥＧＲ弁を通過したＥＧＲガスが吸気通路内に流入して内燃機関の吸気口に到達するまでの挙動を模擬したＥＧＲガス拡散モデルを用いてＥＧＲ弁通過ガス流量の演算値に基づき仮の筒内流入ＥＧＲガス流量を演算する手段と、筒内流入総ガス流量の演算値から仮の筒内流入ＥＧＲガス流量の演算値を差し引いて筒内流入新気流量を求める手段と、新気流量の計測値を用いて筒内流入新気流量の演算値を補正する手段と、補正した筒内流入新気流量の演算値に基づいて吸気管圧力を演算する手段と、少なくとも前記吸気管圧力の演算値を用いて筒内流入ＥＧＲガス流量を演算する手段とを備える。 The in-cylinder inflow EGR gas flow rate estimation device disclosed in Patent Document 1 is a means for calculating the total in-cylinder inflow gas flow rate using an intake valve model and a means for calculating an EGR valve passing gas flow rate using an EGR valve model. Then, using an EGR gas diffusion model that simulates the behavior of EGR gas that has passed through the EGR valve flowing into the intake passage and reaching the intake port of the internal combustion engine, it is provisionally based on the calculated value of the gas flow rate that has passed through the EGR valve. Means for calculating the inflow EGR gas flow rate in the cylinder, means for obtaining the fresh air flow rate in the cylinder by subtracting the calculated value of the temporary inflow EGR gas flow rate from the calculated value of the total inflow gas flow rate in the cylinder, and the fresh air flow rate. A means for correcting the calculated value of the inflow fresh air flow in the cylinder using the measured value of the above, a means for calculating the intake pipe pressure based on the calculated value of the corrected inflow fresh air flow in the cylinder, and at least the means for calculating the intake pipe pressure. A means for calculating the inflow EGR gas flow rate in the cylinder by using the calculated value is provided.

特開２０１２−０９２６８９号公報Japanese Unexamined Patent Publication No. 2012-092689

ところで、ＥＧＲによって筒内に還流される排ガス流量は、排ガス還流配管の分岐、合流や配管長などの影響によって過渡状態で応答遅れが生じる。このため、係る応答遅れを考慮して筒内還流排ガス流量及び筒内流入新気流量を推定しないと、これら推定値に基づき求められる燃料噴射量に誤差が生じ、排気性状や燃焼が悪化するおそれがあった。 By the way, the flow rate of exhaust gas recirculated into the cylinder by EGR causes a response delay in a transient state due to the influence of branching, merging, pipe length, etc. of the exhaust gas recirculation pipe. Therefore, if the in-cylinder exhaust gas flow rate and the in-cylinder inflow fresh air flow rate are not estimated in consideration of the response delay, an error may occur in the fuel injection amount obtained based on these estimated values, and the exhaust properties and combustion may deteriorate. was there.

本発明は、従来の実情に鑑みてなされたものであり、その目的は、ＥＧＲシステムを備えた内燃機関において、過渡状態での排気性状や燃焼を改善できる、制御装置を提供することにある。 The present invention has been made in view of the conventional circumstances, and an object of the present invention is to provide a control device capable of improving exhaust properties and combustion in a transient state in an internal combustion engine equipped with an EGR system.

そのため、本発明に係る制御装置は、その一態様として、スロットル弁通過空気量と筒内流入新気流量と第１の圧力勾配補正値とに基づき、スロットル弁の下流の吸気管における空気分圧を求める空気分圧演算部と、排ガス還流制御弁を介して前記吸気管に還流される排ガス還流量と筒内流入排ガス流量と第２の圧力勾配補正値とに基づき、前記吸気管における還流排ガス分圧を求める還流排ガス分圧演算部と、前記空気分圧及び前記還流排ガス分圧に基づき吸気管圧力を求める吸気管圧力演算部と、前記吸気管圧力と前記スロットル弁の上流の圧力と前記スロットル弁の開度とに基づき前記スロットル弁通過空気量を求めるスロットル弁通過空気量演算部と、前記空気分圧に基づき前記筒内流入新気流量を求める筒内流入新気流量演算部と、前記筒内流入新気流量に基づき前記燃料噴射装置による燃料噴射量を演算する燃料噴射量演算部と、を有する。 Therefore, as one aspect of the control device according to the present invention, the air partial pressure in the intake pipe downstream of the throttle valve is based on the amount of air passing through the throttle valve, the inflow fresh air flow rate in the cylinder, and the first pressure gradient correction value. Based on the air partial pressure calculation unit, the amount of exhaust gas recirculated to the intake pipe via the exhaust gas recirculation control valve, the inflow exhaust gas flow rate in the cylinder, and the second pressure gradient correction value, the recirculated exhaust gas in the intake pipe. The recirculation exhaust gas partial pressure calculation unit for obtaining the partial pressure, the intake pipe pressure calculation unit for obtaining the intake pipe pressure based on the air partial pressure and the recirculation exhaust gas partial pressure, the intake pipe pressure, the pressure upstream of the throttle valve, and the above. A throttle valve passing air amount calculation unit that obtains the throttle valve passing air amount based on the opening degree of the throttle valve, and an in-cylinder inflow fresh air flow rate calculation unit that obtains the in-cylinder inflow fresh air flow rate based on the air partial pressure. It has a fuel injection amount calculation unit that calculates the fuel injection amount by the fuel injection device based on the inflow fresh air flow rate in the cylinder.

上記発明によると、ＥＧＲシステムを備えた内燃機関において、過渡状態での排気性状や燃焼を改善できる。 According to the above invention, in an internal combustion engine equipped with an EGR system, exhaust properties and combustion in a transient state can be improved.

内燃機関のシステム概略図である。It is a system schematic diagram of an internal combustion engine. 燃料噴射量の算出手順を示す機能ブロック図である。It is a functional block diagram which shows the calculation procedure of a fuel injection amount. 圧力勾配補正値の算出手順を示す機能ブロック図である。It is a functional block diagram which shows the calculation procedure of a pressure gradient correction value. 加速状態の基本ゲインＧＢＡと機関回転速度との相関を示す線図である。It is a diagram which shows the correlation between the basic gain GBA of the acceleration state, and the engine rotation speed. 減速状態の基本ゲインＧＢＤと機関回転速度と吸気管圧との相関を示す線図である。It is a diagram which shows the correlation of the basic gain GBD of the deceleration state, the engine rotation speed, and the intake pipe pressure. 加速状態のゲイン補正値ＧＨＡと筒内流入排ガス流量との相関を示す線図である。It is a diagram which shows the correlation of the gain correction value GHA in the acceleration state, and the inflow exhaust gas flow rate in a cylinder. 減速状態のゲイン補正値ＧＨＤと筒内流入排ガス流量との相関を示す線図である。It is a diagram which shows the correlation of the gain correction value GHD in a deceleration state, and the inflow exhaust gas flow rate in a cylinder. 加速状態でのＥＧＲ分圧の応答遅れの特性を示すタイムチャートである。It is a time chart which shows the characteristic of the response delay of the EGR partial pressure in the acceleration state. 減速状態でのＥＧＲ分圧の応答遅れの特性を示すタイムチャートである。It is a time chart which shows the characteristic of the response delay of the EGR partial pressure in the deceleration state. 基本ゲインＧＢＡ、圧力勾配補正ゲインＧＡＡ、及び、圧力勾配補正ゲインＧＥＡの特性を示すタイムチャートである。It is a time chart which shows the characteristic of the basic gain GBA, the pressure gradient correction gain GAA, and the pressure gradient correction gain GEA. 圧力勾配補正値の算出手順を示す機能ブロック図である。It is a functional block diagram which shows the calculation procedure of a pressure gradient correction value. 過渡判定閾値と吸気管圧力との相関を示す線図である。It is a diagram which shows the correlation between the transient determination threshold value and the intake pipe pressure. 圧力勾配補正の第１段階及び第２段階を示すタイムチャートである。It is a time chart which shows the 1st stage and 2nd stage of pressure gradient correction.

以下に本発明の実施の形態を説明する。
図１は、本発明に係る制御装置を適用する内燃機関の一態様を示す図である。
なお、図１に示す内燃機関１は、自動車に動力源として搭載される機関である。 Embodiments of the present invention will be described below.
FIG. 1 is a diagram showing an aspect of an internal combustion engine to which the control device according to the present invention is applied.
The internal combustion engine 1 shown in FIG. 1 is an engine mounted on an automobile as a power source.

内燃機関１の吸気管２は、吸気ダクト２ａ、吸気コレクタ２ｂ、吸気マニホールド２ｃで構成される。
吸気ダクト２ａには、内燃機関１の吸入空気流量ＱＡを検出するエアフローメータ３（流量センサ）、過給機４のコンプレッサ４ａ、電制スロットル装置５が設置される。 The intake pipe 2 of the internal combustion engine 1 is composed of an intake duct 2a, an intake collector 2b, and an intake manifold 2c.
An air flow meter 3 (flow rate sensor) for detecting the intake air flow rate QA of the internal combustion engine 1, a compressor 4a of the supercharger 4, and an electronically controlled throttle device 5 are installed in the intake duct 2a.

電制スロットル装置５は、スロットル弁５ａと、スロットル弁５ａの開度ＴＶＯを検出するスロットルセンサ５ｂと、スロットル弁５ａを開閉するアクチュエータであるスロットルモータ５ｃを備える。
電制スロットル装置５は、内燃機関１の吸入空気流量を調整し、電制スロットル装置５を通過した空気は、吸気コレクタ２ｂ、吸気マニホールド２ｃ、更に吸気弁６を介して内燃機関１の燃焼室７に吸引される。 The electronically controlled throttle device 5 includes a throttle valve 5a, a throttle sensor 5b that detects the opening degree TVO of the throttle valve 5a, and a throttle motor 5c that is an actuator that opens and closes the throttle valve 5a.
The electronically controlled throttle device 5 adjusts the intake air flow rate of the internal combustion engine 1, and the air that has passed through the electronically controlled throttle device 5 passes through the intake collector 2b, the intake manifold 2c, and the intake valve 6 to the combustion chamber of the internal combustion engine 1. It is sucked into 7.

燃料噴射装置１０は、燃焼室７内に燃料を直接噴射し、燃料噴射装置１０が燃焼室７内に噴射した燃料は点火装置１１による火花点火によって着火燃焼する。
そして、燃焼後の排ガスは、排気バルブ１２、排気マニホールド１３を介して排出される。 The fuel injection device 10 directly injects fuel into the combustion chamber 7, and the fuel injected by the fuel injection device 10 into the combustion chamber 7 is ignited and burned by spark ignition by the ignition device 11.
Then, the exhaust gas after combustion is discharged through the exhaust valve 12 and the exhaust manifold 13.

また、内燃機関１は、排ガス還流装置３０、換言すれば、ＥＧＲシステムを備える。
排ガス還流装置３０は、排ガス還流配管３１（ＥＧＲ配管）と排ガス還流制御弁３２（ＥＧＲ制御弁）とを備える。
排ガス還流配管３１は、排気マニホールド１３（排気管）と吸気コレクタ２ｂ（吸気管）とを連通させ、スロットル弁５ａの下流の吸気管２に燃焼後の排ガスを還流させるための還流通路を形成する。 Further, the internal combustion engine 1 includes an exhaust gas recirculation device 30, in other words, an EGR system.
The exhaust gas recirculation device 30 includes an exhaust gas recirculation pipe 31 (EGR pipe) and an exhaust gas recirculation control valve 32 (EGR control valve).
The exhaust gas recirculation pipe 31 communicates the exhaust manifold 13 (exhaust pipe) and the intake collector 2b (intake pipe), and forms a recirculation passage for recirculating the exhaust gas after combustion in the intake pipe 2 downstream of the throttle valve 5a. ..

排ガス還流制御弁３２は、バルブ開度の変更によって排ガス還流配管３１の開口面積を制御することで、排ガス還流配管３１を介して吸気管２に還流される排ガス還流量を制御する。
排ガス還流制御弁３２は、排ガス還流配管３１の開口面積を可変とするバルブ本体３２ａと、バルブ本体３２ａを開閉するステップモータなどのアクチュエータ３２ｂとを備える。 The exhaust gas recirculation control valve 32 controls the opening area of the exhaust gas recirculation pipe 31 by changing the valve opening degree, thereby controlling the amount of exhaust gas recirculation returned to the intake pipe 2 via the exhaust gas recirculation pipe 31.
The exhaust gas recirculation control valve 32 includes a valve body 32a that makes the opening area of the exhaust gas recirculation pipe 31 variable, and an actuator 32b such as a step motor that opens and closes the valve body 32a.

制御装置５０は、ＭＰＵ（Microprocessor Unit）５１、ＲＯＭ（Read Only Memory）５２、ＲＡＭ（Random Access Memory）５３を含むマイクロコンピュータ５４を主体とする電子制御装置である。
そして、制御装置５０は、入力した情報に基づいて演算を行い、演算した結果を電制スロットル装置５、燃料噴射装置１０、点火装置１１、排ガス還流制御弁３２などに出力して内燃機関１の運転を制御する、コントロール部としての機能をソフトウェアとして備える。 The control device 50 is an electronic control device mainly composed of a microcomputer 54 including an MPU (Microprocessor Unit) 51, a ROM (Read Only Memory) 52, and a RAM (Random Access Memory) 53.
Then, the control device 50 performs a calculation based on the input information, outputs the calculated result to the electronically controlled throttle device 5, the fuel injection device 10, the ignition device 11, the exhaust gas recirculation control valve 32, and the like, and outputs the calculation result to the internal combustion engine 1. The software has a function as a control unit that controls operation.

制御装置５０は、内燃機関１の運転状態を検出する各種センサが出力する信号を取得する。
内燃機関１は、各種センサとして、前述のエアフローメータ３、スロットルセンサ５ｂの他、吸気コレクタ２ｂ内の圧力である吸気管圧力ＰＢを検出する吸気管圧力センサ１７、内燃機関１の回転に応じたパルス信号ＰＯＳを出力する回転センサ１８、吸気温度ＴＡを検出する吸気温度センサ１９、内燃機関１の冷却水温度ＴＷを検出する水温センサ２０、内燃機関１の排ガスの酸素濃度に基づき空燃比Ａ／Ｆを検出する空燃比センサ２１などを備える。 The control device 50 acquires signals output by various sensors that detect the operating state of the internal combustion engine 1.
As various sensors, the internal combustion engine 1 responds to the rotation of the air flow meter 3 and the throttle sensor 5b, the intake pipe pressure sensor 17 for detecting the intake pipe pressure PB which is the pressure in the intake collector 2b, and the internal combustion engine 1. An air-fuel ratio A / based on the rotation sensor 18 that outputs the pulse signal POS, the intake air temperature sensor 19 that detects the intake air temperature TA, the water temperature sensor 20 that detects the cooling water temperature TW of the internal combustion engine 1, and the oxygen concentration of the exhaust gas of the internal combustion engine 1. It is provided with an air-fuel ratio sensor 21 for detecting F and the like.

制御装置５０は、燃料噴射装置１０の開弁駆動する噴射パルス信号、換言すれば、燃料噴射制御信号を出力し、前記噴射パルス信号のパルス幅である燃料噴射パルス幅の設定によって燃料噴射装置１０による燃料噴射量を制御する。
そして、制御装置５０は、燃料噴射パルス幅を算出する処理において、燃焼室７に流入する新気の流量である筒内流入新気流量を推定し、推定した筒内流入新気流量に基づき燃料噴射パルス幅、つまり、燃料噴射装置１０による燃料噴射量を算出する。 The control device 50 outputs an injection pulse signal for driving the valve opening of the fuel injection device 10, in other words, a fuel injection control signal, and the fuel injection device 10 is set by setting the fuel injection pulse width which is the pulse width of the injection pulse signal. Controls the fuel injection amount by.
Then, in the process of calculating the fuel injection pulse width, the control device 50 estimates the in-cylinder inflow fresh air flow rate, which is the flow rate of the fresh air flowing into the combustion chamber 7, and fuels based on the estimated in-cylinder inflow fresh air flow rate. The injection pulse width, that is, the fuel injection amount by the fuel injection device 10 is calculated.

図２は、制御装置５０における燃料噴射パルス幅（燃料噴射量）の算出手順の一態様を示す機能ブロック図である。
吸入空気量検出部１０１は、エアフローメータ３が出力する吸入空気流量ＱＡに関する信号を取得し、吸入空気流量ＱＡのデータに変換する。 FIG. 2 is a functional block diagram showing one aspect of the procedure for calculating the fuel injection pulse width (fuel injection amount) in the control device 50.
The intake air amount detection unit 101 acquires a signal regarding the intake air flow rate QA output by the air flow meter 3 and converts it into data of the intake air flow rate QA.

圧力推定部１０２は、コンプレッサ４ａと電制スロットル装置５との間の吸気管２における圧力であるコンプレッサ−スロットル間圧力ＰＢＣを推定する処理部である。
圧力推定部１０２は、吸入空気量検出部１０１から取得した吸入空気流量ＱＡのデータ、コンプレッサ−スロットル間圧力ＰＢＣの前回値ＰＢＣ-1、及び、後述するスロットル弁通過空気量演算部１０３が推定したスロットル弁通過空気量ＱＡＦの前回値ＱＡＦ-1に基づき、コンプレッサ−スロットル間圧力ＰＢＣを求める。
つまり、圧力推定部１０２は、エアフローメータ３を通過した新気流量と、スロットル弁通過空気量ＱＡＦとの流量差からコンプレッサ４ａと電制スロットル装置５との間の圧力変化を推定する。 The pressure estimation unit 102 is a processing unit that estimates the compressor-throttle pressure PBC, which is the pressure in the intake pipe 2 between the compressor 4a and the electronically controlled throttle device 5.
The pressure estimation unit 102 estimated the intake air flow rate QA data acquired from the intake air amount detection unit 101, the previous value PBC -1 of the compressor-throttle pressure PBC, and the throttle valve passing air amount calculation unit 103 described later. The compressor-throttle pressure PBC is obtained based on the previous value QAF -1 of the amount of air passing through the throttle valve QAF.
That is, the pressure estimation unit 102 estimates the pressure change between the compressor 4a and the electronically controlled throttle device 5 from the flow rate difference between the fresh air flow rate passing through the air flow meter 3 and the air flow rate QAF passing through the throttle valve.

スロットル弁通過空気量演算部１０３は、圧力推定部１０２が推定したコンプレッサ−スロットル間圧力ＰＢＣ、スロットル弁５ａの開口面積に相当するスロットル弁５ａの開度ＴＶＯ、及び、後述する吸気管圧力演算部１１０が推定したスロットル弁５ａ下流の吸気管２内の圧力である吸気管圧力ＰＢＥに基づき、スロットル弁通過空気量ＱＡＦを求める。
ここで、スロットル弁通過空気量演算部１０３は、コンプレッサ−スロットル間圧力ＰＢＣと吸気管圧力ＰＢＥとに基づき、スロットル弁５ａを逆流する空気流量を考慮して、スロットル弁５ａから下流の吸気管２に流入する空気量を推定する。 The throttle valve passing air amount calculation unit 103 includes a compressor-throttle pressure PBC estimated by the pressure estimation unit 102, an opening TVO of the throttle valve 5a corresponding to the opening area of the throttle valve 5a, and an intake pipe pressure calculation unit described later. Based on the intake pipe pressure PBE, which is the pressure in the intake pipe 2 downstream of the throttle valve 5a estimated by 110, the amount of air passing through the throttle valve QAF is obtained.
Here, the throttle valve passing air amount calculation unit 103 considers the air flow rate flowing back through the throttle valve 5a based on the compressor-throttle pressure PBC and the intake pipe pressure PBE, and the intake pipe 2 downstream from the throttle valve 5a. Estimate the amount of air flowing into.

空気分圧演算部１０４は、スロットル弁５ａと吸気弁６との間の吸気管２における空気分圧ＰＰＡを推定する処理部である。
空気分圧演算部１０４は、スロットル弁通過空気量演算部１０３が推定したスロットル弁通過空気量ＱＡＦ、空気分圧ＰＰＡの圧力勾配を補正する第１の圧力勾配補正値ＰＧＣＡ、後述する筒内流入新気流量演算部１０５が推定した筒内流入新気流量ＱＡＣの前回値ＱＡＣ-1、空気分圧ＰＰＡの前回値ＰＰＡ-1に基づき、空気分圧ＰＰＡを求める。 The air partial pressure calculation unit 104 is a processing unit that estimates the air partial pressure PPA in the intake pipe 2 between the throttle valve 5a and the intake valve 6.
The air partial pressure calculation unit 104 includes a throttle valve passing air amount QAF estimated by the throttle valve passing air amount calculation unit 103, a first pressure gradient correction value PGCA for correcting the pressure gradient of the air partial pressure PPA, and an inflow into the cylinder described later. The air partial pressure PPA is obtained based on the previous value QAC -1 of the inflow fresh air flow rate QAC estimated by the fresh air flow rate calculation unit 105 and the previous value PPA -1 of the air partial pressure PPA.

空気分圧演算部１０４は、例えば、以下の数式（１）にしたがって空気分圧ＰＰＡ（空気分圧推定値）を更新する。
ＰＰＡ＝ＰＰＡ-1＋ＰＧＣＡ＊（ＱＡＦ−ＱＡＣ-1）…（１）
つまり、空気分圧演算部１０４は、スロットル弁通過空気量ＱＡＦと筒内流入新気流量ＱＡＣの前回値ＱＡＣ-1との差分に第１の圧力勾配補正値ＰＧＣＡを乗算して、空気分圧ＰＰＡの変化分を演算し、係る圧力変化分を空気分圧ＰＰＡの前回値ＰＰＡ-1に加算して空気分圧ＰＰＡを求める。 The air partial pressure calculation unit 104 updates the air partial pressure PPA (air partial pressure estimated value) according to the following mathematical formula (1), for example.
PPA = PPA -1 + PGCA * (QAF-QAC -1 ) ... (1)
That is, the air partial pressure calculation unit 104 multiplies the difference between the throttle valve passing air amount QAF and the previous value QAC -1 of the inflow fresh air flow rate QAC by the first pressure gradient correction value PGCA to divide the air pressure. The change in PPA is calculated, and the change in pressure is added to the previous value PPA -1 of the partial pressure PPA to obtain the partial pressure PPA.

筒内流入新気流量演算部１０５は、吸気弁６を介して燃焼室７内に流入する新気の流量である筒内流入新気流量ＱＡＣを推定する処理部である。
筒内流入新気流量演算部１０５は、空気分圧演算部１０４が推定した空気分圧ＰＰＡ、内燃機関１の充填効率η、機関回転速度ＮＥに基づき、筒内流入新気流量ＱＡＣを求める。
なお、制御装置５０は、機関回転速度ＮＥを回転センサ１８が出力するパルス信号ＰＯＳに基づき求め、充填効率ηを、例えば、機関回転速度ＮＥ及び吸気管圧力センサ１７が検出した吸気管圧力ＰＢに基づき求める。 The in-cylinder inflow fresh air flow rate calculation unit 105 is a processing unit that estimates the in-cylinder inflow fresh air flow rate QAC, which is the flow rate of the fresh air flowing into the combustion chamber 7 via the intake valve 6.
The in-cylinder inflow fresh air flow rate calculation unit 105 obtains the in-cylinder inflow fresh air flow rate QAC based on the air partial pressure PPA estimated by the air partial pressure calculation unit 104, the filling efficiency η of the internal combustion engine 1, and the engine rotation speed NE.
The control device 50 obtains the engine rotation speed NE based on the pulse signal POS output by the rotation sensor 18, and sets the filling efficiency η to, for example, the engine rotation speed NE and the intake pipe pressure PB detected by the intake pipe pressure sensor 17. Obtained based on.

基本燃料噴射量演算部１０６は、筒内流入新気流量演算部１０５が求めた筒内流入新気流量ＱＡＣに基づき、目標空燃比の混合気を形成するための基本燃料噴射量に相当する基本燃料噴射パルス幅ＴＰを演算する。
制御装置５０は、基本燃料噴射パルス幅ＴＰに、冷却水温度ＴＷや空燃比Ａ／Ｆの検出値による補正などを加えて最終的な燃料噴射パルス幅ＴＩを演算し、所定の噴射タイミングで燃料噴射パルス幅ＴＩの燃料噴射パルス信号を燃料噴射装置１０に出力する。 The basic fuel injection amount calculation unit 106 is based on the in-cylinder inflow fresh air flow rate QAC obtained by the in-cylinder inflow fresh air flow rate calculation unit 105, and corresponds to the basic fuel injection amount for forming an air-fuel mixture with a target air-fuel ratio. Calculate the fuel injection pulse width TP.
The control device 50 calculates the final fuel injection pulse width TI by adding corrections based on the cooling water temperature TW and the detected value of the air-fuel ratio A / F to the basic fuel injection pulse width TP, and fuels at a predetermined injection timing. The fuel injection pulse signal having the injection pulse width TI is output to the fuel injection device 10.

排ガス還流量演算部１０７は、排ガス還流制御弁３２を介して吸気管２に還流される排ガス還流量ＱＥＧＲを演算する処理部である。
排ガス還流量演算部１０７は、排ガス還流制御弁３２の開度、吸気管圧力センサ１７が検出した吸気管圧力ＰＢ、排気圧演算値に基づき、排ガス還流量ＱＥＧＲを演算する。 The exhaust gas recirculation amount calculation unit 107 is a processing unit that calculates the exhaust gas recirculation amount QEGR that is recirculated to the intake pipe 2 via the exhaust gas recirculation control valve 32.
The exhaust gas recirculation amount calculation unit 107 calculates the exhaust gas recirculation amount QEGR based on the opening degree of the exhaust gas recirculation control valve 32, the intake pipe pressure PB detected by the intake pipe pressure sensor 17, and the exhaust gas pressure calculation value.

制御装置５０は、排ガス還流制御弁３２の開度を、例えば、排ガス還流制御弁３２を開閉するステップモータのステップ数から求め、また、排気圧演算値を、例えば、機関負荷、機関回転速度、大気圧などから求める。なお、制御装置５０は、機関負荷を、例えば、筒内流入新気流量ＱＡＣ、排気量、空気密度、機関回転速度などに基づき求める。
ここで、排ガス還流量演算部１０７は、吸気管圧力ＰＢと排気圧演算値との差圧と、排ガス還流制御弁３２の開度（開口面積）から排ガス還流量ＱＥＧＲを演算する。 The control device 50 obtains the opening degree of the exhaust gas recirculation control valve 32 from, for example, the number of steps of the step motor for opening and closing the exhaust gas recirculation control valve 32, and obtains the exhaust pressure calculated value, for example, the engine load, the engine rotation speed, and the like. Obtained from atmospheric pressure. The control device 50 obtains the engine load based on, for example, the inflow fresh air flow rate QAC in the cylinder, the displacement, the air density, the engine rotation speed, and the like.
Here, the exhaust gas recirculation amount calculation unit 107 calculates the exhaust gas recirculation amount QEGR from the difference pressure between the intake pipe pressure PB and the exhaust gas calculated value and the opening degree (opening area) of the exhaust gas recirculation control valve 32.

ＥＧＲ分圧演算部１０８は、スロットル弁５ａと吸気弁６との間の吸気管２における還流排ガスの分圧であるＥＧＲ分圧ＰＰＥを推定する処理部である。
ＥＧＲ分圧演算部１０８は、排ガス還流量演算部１０７が推定した排ガス還流量ＱＥＧＲ、ＥＧＲ分圧ＰＰＥの圧力勾配を補正する第２の圧力勾配補正値ＰＧＣＥ、後述する筒内流入排ガス流量演算部１０９が推定した筒内流入排ガス流量ＱＥＣの前回値ＱＥＣ-1、ＥＧＲ分圧ＰＰＥの前回値ＰＰＥ-1に基づき、ＥＧＲ分圧ＰＰＥを演算する。 The EGR partial pressure calculation unit 108 is a processing unit that estimates the EGR partial pressure PPE, which is the partial pressure of the recirculated exhaust gas in the intake pipe 2 between the throttle valve 5a and the intake valve 6.
The EGR partial pressure calculation unit 108 includes an exhaust gas recirculation amount QEGR estimated by the exhaust gas recirculation amount calculation unit 107, a second pressure gradient correction value PGC that corrects the pressure gradient of the EGR partial pressure PPE, and an in-cylinder inflow exhaust gas flow rate calculation unit described later. The EGR partial pressure PPE is calculated based on the previous value QEC -1 of the inflow exhaust gas flow rate QEC estimated by 109 and the previous value PPE -1 of the EGR partial pressure PPE.

ＥＧＲ分圧演算部１０８は、例えば、以下の数式（２）にしたがってＥＧＲ分圧ＰＰＥ（ＥＧＲ分圧推定値）を更新する。
ＰＰＥ＝ＰＰＥ-1＋ＰＧＣＥ＊（ＱＥＧＲ−ＱＥＣ-1）…（２）
つまり、ＥＧＲ分圧演算部１０８は、排ガス還流量ＱＥＧＲと筒内流入排ガス流量ＱＥＣの前回値ＱＥＣ-1との差分に第２の圧力勾配補正値ＰＧＣＥを乗算して、ＥＧＲ分圧ＰＰＥの変化分を演算し、係る圧力変化分をＥＧＲ分圧ＰＰＥの前回値ＰＰＥ-1に加算してＥＧＲ分圧ＰＰＥを求める。 The EGR partial pressure calculation unit 108 updates the EGR partial pressure PPE (EGR partial pressure estimated value) according to the following mathematical formula (2), for example.
PPE = PPE -1 + PGCE * (QEGR-QEC -1 ) ... (2)
That is, the EGR partial pressure calculation unit 108 multiplies the difference between the exhaust gas recirculation amount QEGR and the previous value QEC -1 of the inflow exhaust gas flow rate QEC by the second pressure gradient correction value PGC, and changes the EGR partial pressure PPE. Minutes are calculated, and the relevant pressure change is added to the previous value PPE -1 of the EGR partial pressure PPE to obtain the EGR partial pressure PPE.

筒内流入排ガス流量演算部１０９は、吸気管２から吸気弁６を介して燃焼室７内に流入する還流排ガスの流量である筒内流入排ガス流量ＱＥＣを推定する処理部である。
筒内流入排ガス流量演算部１０９は、ＥＧＲ分圧演算部１０８が推定したＥＧＲ分圧ＰＰＥ、内燃機関１の充填効率η、機関回転速度ＮＥに基づき、筒内流入排ガス流量ＱＥＣを求める。 The in-cylinder inflow exhaust gas flow rate calculation unit 109 is a processing unit that estimates the in-cylinder inflow exhaust gas flow rate QEC, which is the flow rate of the recirculated exhaust gas flowing from the intake pipe 2 to the combustion chamber 7 via the intake valve 6.
The in-cylinder inflow exhaust gas flow rate calculation unit 109 obtains the in-cylinder inflow exhaust gas flow rate QEC based on the EGR partial pressure PPE estimated by the EGR partial pressure calculation unit 108, the filling efficiency η of the internal combustion engine 1, and the engine rotation speed NE.

吸気管圧力演算部１１０は、スロットル弁５ａと吸気弁６との間の吸気管２内の圧力である吸気管圧力ＰＢＥを推定する処理部である。
吸気管圧力演算部１１０は、空気分圧演算部１０４が推定した空気分圧ＰＰＡ、及び、ＥＧＲ分圧演算部１０８が推定したＥＧＲ分圧ＰＰＥに基づき、吸気管圧力ＰＢＥを演算する。
吸気管圧力演算部１１０が求めた吸気管圧力ＰＢＥのデータは、スロットル弁通過空気量演算部１０３に出力され、スロットル弁通過空気量演算部１０３におけるスロットル弁通過空気量ＱＡＦの演算に用いられる。 The intake pipe pressure calculation unit 110 is a processing unit that estimates the intake pipe pressure PBE, which is the pressure in the intake pipe 2 between the throttle valve 5a and the intake valve 6.
The intake pipe pressure calculation unit 110 calculates the intake pipe pressure PBE based on the air partial pressure PPA estimated by the air partial pressure calculation unit 104 and the EGR partial pressure PPE estimated by the EGR partial pressure calculation unit 108.
The data of the intake pipe pressure PBE obtained by the intake pipe pressure calculation unit 110 is output to the throttle valve passing air amount calculation unit 103, and is used in the calculation of the throttle valve passing air amount QAF in the throttle valve passing air amount calculation unit 103.

図３は、制御装置５０における第１の圧力勾配補正値ＰＧＣＡ及び第２の圧力勾配補正値ＰＧＣＥの算出手順、つまり、圧力勾配補正値演算部２００の一態様を示す機能ブロック図である。
第１の圧力勾配補正値ＰＧＣＡは、図２の空気分圧演算部１０４が空気分圧ＰＰＡの圧力勾配の補正に用いる補正項であって、空気分圧ＰＰＡの過渡応答の特性設定値である。
また、第２の圧力勾配補正値ＰＧＣＥは、図２のＥＧＲ分圧演算部１０８がＥＧＲ分圧ＰＰＥの圧力勾配の補正に用いる補正項であって、ＥＧＲ分圧ＰＰＥの過渡応答の特性設定値である。 FIG. 3 is a functional block diagram showing a procedure for calculating the first pressure gradient correction value PGCA and the second pressure gradient correction value PGCE in the control device 50, that is, one aspect of the pressure gradient correction value calculation unit 200.
The first pressure gradient correction value PGCA is a correction term used by the air partial pressure calculation unit 104 in FIG. 2 to correct the pressure gradient of the air partial pressure PPA, and is a characteristic setting value of the transient response of the air partial pressure PPA. ..
The second pressure gradient correction value PGC is a correction term used by the EGR partial pressure calculation unit 108 in FIG. 2 to correct the pressure gradient of the EGR partial pressure PPE, and is a characteristic setting value of the transient response of the EGR partial pressure PPE. Is.

加減速検出部１５１は、内燃機関１が定常状態、加速状態、減速状態のいずれの状態であるかを、例えば、吸気管圧力センサ１７が検出する吸気管圧力ＰＢの単位時間当たりの変化量の絶対値、及び、変化方向に基づき検出し、検出結果に関する信号を出力する。
加減速検出部１５１は、例えば、吸気管圧力ＰＢの単位時間当たりの変化量ΔＰＢの絶対値が閾値以下であるとき、内燃機関１が定常状態であると判定し、変化量ΔＰＢの絶対値が前記閾値を超えるとき、内燃機関１が過渡状態であると判定する。 The acceleration / deceleration detection unit 151 determines whether the internal combustion engine 1 is in a steady state, an acceleration state, or a deceleration state, for example, the amount of change in the intake pipe pressure PB per unit time detected by the intake pipe pressure sensor 17. Detects based on the absolute value and the direction of change, and outputs a signal related to the detection result.
For example, when the absolute value of the change amount ΔPB per unit time of the intake pipe pressure PB is equal to or less than the threshold value, the acceleration / deceleration detection unit 151 determines that the internal combustion engine 1 is in a steady state, and the absolute value of the change amount ΔPB is When the threshold value is exceeded, it is determined that the internal combustion engine 1 is in a transient state.

そして、加減速検出部１５１は、前記変化量ΔＰＢの絶対値が前記閾値を超え、かつ、吸気管圧力ＰＢが増大方向（換言すれば、負圧から正圧に向かう方向）に変化しているとき、内燃機関１が加速状態であると判定する。
また、加減速検出部１５１は、前記変化量ΔＰＢの絶対値が前記閾値を超え、かつ、吸気管圧力ＰＢが減少方向（換言すれば、正圧から負圧に向かう方向）に変化しているとき、内燃機関１が減速状態であると判定する。 Then, in the acceleration / deceleration detection unit 151, the absolute value of the change amount ΔPB exceeds the threshold value, and the intake pipe pressure PB changes in the increasing direction (in other words, the direction from the negative pressure to the positive pressure). At this time, it is determined that the internal combustion engine 1 is in the accelerating state.
Further, in the acceleration / deceleration detection unit 151, the absolute value of the change amount ΔPB exceeds the threshold value, and the intake pipe pressure PB changes in the decreasing direction (in other words, the direction from the positive pressure to the negative pressure). At this time, it is determined that the internal combustion engine 1 is in the decelerated state.

なお、加減速検出部１５１は、スロットル開度や機関回転速度などから定常／過渡の判定を行うことができる。
また、加減速検出部１５１は、定常／過渡の他に始動後のファーストアイドル状態を判定し、後述するゲインの選択処理において、定常、過渡、始動後のファーストアイドル状態の別に応じてゲイン選択を行うシステムとすることができる。 The acceleration / deceleration detection unit 151 can determine steady / transient based on the throttle opening degree, engine rotation speed, and the like.
Further, the acceleration / deceleration detection unit 151 determines the fast idle state after starting in addition to the steady / transient state, and in the gain selection process described later, the gain selection is performed according to the steady, transient, and fast idle state after starting. It can be a system to do.

基本ゲイン演算部１５２は、吸気管２内の推定圧力値（圧力演算値）の過渡応答を補正するための補正項（圧力勾配補正値）の基本値である基本ゲインＧＢＡ，ＧＢＤを、内燃機関１の運転状態（負荷及び／又は回転速度）に基づき求める。
後述するように、基本ゲインＧＢＡは内燃機関１の加速状態で推定圧力値の増大変化を補正するための補正項で、基本ゲインＧＢＤは内燃機関１の減速状態で推定圧力値の減少変化を補正するための補正項である。 The basic gain calculation unit 152 sets the basic gains GBA and GBD, which are the basic values of the correction terms (pressure gradient correction value) for correcting the transient response of the estimated pressure value (pressure calculation value) in the intake pipe 2, to the internal combustion engine. Obtained based on the operating condition (load and / or rotation speed) of 1.
As will be described later, the basic gain GBA is a correction term for correcting an increase change in the estimated pressure value in the acceleration state of the internal combustion engine 1, and the basic gain GBD corrects a decrease change in the estimated pressure value in the deceleration state of the internal combustion engine 1. It is a correction term for doing.

また、基本ゲインＧＢＡ，ＧＢＤは、排ガス還流装置３０による排ガスの還流が停止されているときに、空気分圧演算部１０４が基本ゲインＧＢＡ，ＧＢＤに基づき求める空気分圧ＰＰＡの演算値が、吸気管圧力センサ１７が検出する吸気管圧力ＰＢに近似するように適合されている。
なお、排ガス還流の停止状態とは、排ガス還流制御弁３２が最小開度若しくは全閉に制御されていて、排ガス還流量が最小量若しくは零のときである。 Further, in the basic gains GBA and GBD, when the reflux of the exhaust gas by the exhaust gas recirculation device 30 is stopped, the calculated value of the air partial pressure PPA obtained by the air partial pressure calculation unit 104 based on the basic gains GBA and GBD is the intake air. It is adapted to approximate the intake pipe pressure PB detected by the pipe pressure sensor 17.
The exhaust gas recirculation stop state is when the exhaust gas recirculation control valve 32 is controlled to the minimum opening degree or the fully closed state and the exhaust gas recirculation amount is the minimum amount or zero.

基本ゲイン演算部１５２は、内燃機関１が加速状態であるときに推定圧力値の立ち上がり応答を補正するための基本ゲインＧＢＡ（ＧＢＡ＞０）を、機関回転速度ＮＥに基づき求める。
図４は、加速状態で用いる基本ゲインＧＢＡと機関回転速度ＮＥとの相関の一態様を示す図である。 The basic gain calculation unit 152 obtains the basic gain GBA (GBA> 0) for correcting the rising response of the estimated pressure value when the internal combustion engine 1 is in the accelerating state, based on the engine rotation speed NE.
FIG. 4 is a diagram showing one aspect of the correlation between the basic gain GBA used in the acceleration state and the engine rotation speed NE.

機関回転速度ＮＥが高いほどガス流速が速くなるため、吸気管２内の圧力の立ち上がり応答は、機関回転速度ＮＥが高いほど速くなる。
このため、基本ゲイン演算部１５２は、機関回転速度ＮＥが高いほど基本ゲインＧＢＡをより大きな値に設定し、基本ゲインＧＢＡに基づく補正によって加速状態での推定圧力値の立ち上がり応答を速める。 Since the gas flow velocity becomes faster as the engine rotation speed NE is higher, the rising response of the pressure in the intake pipe 2 becomes faster as the engine rotation speed NE is higher.
Therefore, the basic gain calculation unit 152 sets the basic gain GBA to a larger value as the engine rotation speed NE is higher, and accelerates the rising response of the estimated pressure value in the accelerated state by the correction based on the basic gain GBA.

一方、基本ゲイン演算部１５２は、内燃機関１が減速状態であるときに推定圧力値の減少応答を補正するための基本ゲインＧＢＤ（ＧＢＤ＞０）を、機関回転速度ＮＥ、及び、吸気管圧力センサ１７が検出する吸気管圧力ＰＢ（換言すれば、機関負荷）に基づき求める。
図５は、減速状態で用いる基本ゲインＧＢＤと、機関回転速度ＮＥ及び吸気管圧力ＰＢとの相関の一態様を示す図である。 On the other hand, the basic gain calculation unit 152 sets the basic gain GBD (GBD> 0) for correcting the decrease response of the estimated pressure value when the internal combustion engine 1 is in the deceleration state, the engine rotation speed NE, and the intake pipe pressure. It is obtained based on the intake pipe pressure PB (in other words, the engine load) detected by the sensor 17.
FIG. 5 is a diagram showing one aspect of the correlation between the basic gain GBD used in the deceleration state, the engine rotation speed NE, and the intake pipe pressure PB.

基本ゲイン演算部１５２は、機関回転速度ＮＥが高くガス流速が速くなるほど、基本ゲインＧＢＤをより大きな値に設定し、基本ゲインＧＢＤに基づく補正によって減速状態での推定圧力値の減少応答を速める。
また、基本ゲイン演算部１５２は、吸気管圧力ＰＢが高く吸気管２内の気体が筒内へ流入し易くなるほど、基本ゲインＧＢＤをより大きな値に設定し、基本ゲインＧＢＤに基づく補正によって減速状態での推定圧力値の減少応答を速める。 The basic gain calculation unit 152 sets the basic gain GBD to a larger value as the engine rotation speed NE is higher and the gas flow velocity is faster, and the reduction response of the estimated pressure value in the deceleration state is accelerated by the correction based on the basic gain GBD.
Further, the basic gain calculation unit 152 sets the basic gain GBD to a larger value as the intake pipe pressure PB is higher and the gas in the intake pipe 2 is more likely to flow into the cylinder, and the deceleration state is reduced by the correction based on the basic gain GBD. Accelerate the decrease response of the estimated pressure value at.

ゲイン補正値演算部１５３は、筒内流入排ガス流量演算部１０９が求めた筒内流入排ガス流量ＱＥＣ、つまり、ＥＧＲ分圧ＰＰＥに基づき求められた筒内流入排ガス流量ＱＥＣに基づき、基本ゲインＧＢＡ，ＧＢＤを補正するための補正値であるゲイン補正値ＧＨＡ，ＧＨＤを求める。
制御装置５０は、基本ゲインＧＢＡ，ＧＢＤをゲイン補正値ＧＨＡ，ＧＨＤに基づき補正することで、排ガス還流の実施状態での実際の空気分圧の応答特性に適合する圧力勾配補正ゲインＧＡＡ，ＧＡＤ及び実際のＥＧＲ分圧の応答特性に適合する圧力勾配補正ゲインＧＥＡ，ＧＥＤを求める。 The gain correction value calculation unit 153 is based on the in-cylinder inflow exhaust gas flow rate QEC obtained by the in-cylinder inflow exhaust gas flow rate calculation unit 109, that is, the in-cylinder inflow exhaust gas flow rate QEC obtained based on the EGR partial pressure PPE, and the basic gain GBA, The gain correction values GHA and GHD, which are the correction values for correcting the GBD, are obtained.
The control device 50 corrects the basic gains GBA and GBD based on the gain correction values GHA and GHD, so that the pressure gradient correction gains GAA, GAD and GAA, GAD and the pressure gradient correction gains that match the actual air partial pressure response characteristics in the exhaust gas recirculation state are implemented. The pressure gradient correction gains GEA and GED that match the response characteristics of the actual EGR partial pressure are obtained.

これにより、過渡状態での還流排ガスの遅れに応じて空気分圧ＰＰＡ及びＥＧＲ分圧ＰＰＥを高精度に推定でき、排ガス還流が行われる内燃機関１の過渡状態での吸気管圧力ＰＢＥ、スロットル弁通過空気量ＱＡＦ、更には、筒内流入新気流量ＱＡＣの推定精度が向上する。
このため、過渡状態における内燃機関１の空燃比制御精度が改善されて、過渡状態における排気性状や燃焼性が向上する。
なお、過渡状態での還流排ガスの遅れは、排ガス還流配管３１の分岐、合流や配管長などの影響によって生じる。 As a result, the air partial pressure PPA and EGR partial pressure PPE can be estimated with high accuracy according to the delay of the recirculated exhaust gas in the transient state, and the intake pipe pressure PBE and the throttle valve in the transient state of the internal combustion engine 1 in which the exhaust gas recirculation is performed. The estimation accuracy of the passing air amount QAF and the inflow fresh air flow rate QAC in the cylinder is improved.
Therefore, the air-fuel ratio control accuracy of the internal combustion engine 1 in the transient state is improved, and the exhaust properties and combustibility in the transient state are improved.
The delay of the recirculated exhaust gas in the transient state is caused by the influence of the branching, merging, and pipe length of the exhaust gas recirculation pipe 31.

図６は、基本ゲインＧＢＡの補正に用いるゲイン補正値ＧＨＡと、筒内流入排ガス流量ＱＥＣとの相関の一態様を示す。
ゲイン補正値演算部１５３は、内燃機関１の加速状態に適合する基本ゲインＧＢＡを補正するためのゲイン補正値ＧＨＡを、筒内流入排ガス流量ＱＥＣが零であるとき、換言すれば、排ガス還流の停止状態であるときに零とし、筒内流入排ガス流量ＱＥＣが多いほど絶対値としてより大きな値に設定する。 FIG. 6 shows one aspect of the correlation between the gain correction value GHA used for correcting the basic gain GBA and the inflow exhaust gas flow rate QEC in the cylinder.
The gain correction value calculation unit 153 sets the gain correction value GHA for correcting the basic gain GBA that matches the acceleration state of the internal combustion engine 1 when the inflow exhaust gas flow rate QEC in the cylinder is zero, in other words, the exhaust gas return. It is set to zero when in the stopped state, and is set to a larger value as an absolute value as the inflow exhaust gas flow rate QEC in the cylinder increases.

なお、図６及び後述する図７においては、排ガス還流の過渡応答が基本ゲインＧＢＡ，ＧＢＤに相当する過渡応答よりも遅れることを、ゲイン補正値ＧＨＡ，ＧＨＤをマイナスの値にして表している。
但し、ゲイン補正値演算部１５３は、ゲイン補正値ＧＨＡ，ＧＨＤを、筒内流入排ガス流量ＱＥＣが多いほど絶対値の大きなプラスの値として求めることができる。
そして、ゲイン補正値演算部１５３は、ゲイン補正値ＧＨＡ，ＧＨＤを、筒内流入排ガス流量ＱＥＣが多いほど絶対値の大きな値に設定することで、第１の圧力勾配補正値ＰＧＣＡ及び第２の圧力勾配補正値ＰＧＣＥとの偏差は、筒内流入排ガス流量ＱＥＣが多いほど大きくする。 In FIG. 6 and FIG. 7 described later, the gain correction values GHA and GHD are set to negative values to indicate that the transient response of the exhaust gas recirculation is delayed from the transient response corresponding to the basic gains GBA and GBD.
However, the gain correction value calculation unit 153 can obtain the gain correction values GHA and GHD as positive values having a larger absolute value as the inflow exhaust gas flow rate QEC in the cylinder increases.
Then, the gain correction value calculation unit 153 sets the gain correction values GHA and GHD to a value having a larger absolute value as the inflow exhaust gas flow rate QEC in the cylinder increases, so that the first pressure gradient correction value PGCA and the second pressure gradient correction value PGCA and the second The deviation from the pressure gradient correction value PGCE increases as the inflow exhaust gas flow rate QEC in the cylinder increases.

図７は、基本ゲインＧＢＤの補正に用いるゲイン補正値ＧＨＤと、筒内流入排ガス流量ＱＥＣとの相関の一態様を示す。
ゲイン補正値演算部１５３は、内燃機関１の減速状態に適合する基本ゲインＧＢＤを補正するためのゲイン補正値ＧＨＤを、筒内流入排ガス流量ＱＥＣが零であるとき（換言すれば、排ガス還流の停止状態であるとき）に零とし、筒内流入排ガス流量ＱＥＣが多いほど絶対値としてより大きな値に設定する。 FIG. 7 shows one aspect of the correlation between the gain correction value GHD used for correcting the basic gain GBD and the inflow exhaust gas flow rate QEC in the cylinder.
The gain correction value calculation unit 153 sets the gain correction value GHD for correcting the basic gain GBD that matches the deceleration state of the internal combustion engine 1 when the inflow exhaust gas flow rate QEC in the cylinder is zero (in other words, the exhaust gas return). It is set to zero in the stopped state), and the larger the inflow exhaust gas flow rate QEC in the cylinder, the larger the absolute value is set.

ゲイン補正値演算部１５３は、筒内流入排ガス流量ＱＥＣが多いときほど過渡状態における排ガス還流の遅れが大きくなるため、筒内流入排ガス流量ＱＥＣが多いときほど（換言すれば、排ガス還流の応答遅れが大きいほど）、ゲイン補正値ＧＨＡ，ＧＨＤを絶対値としてより大きな値に設定する。
なお、筒内流入排ガス流量ＱＥＣが零である排ガス還流の停止状態では、ゲイン補正値ＧＨＡ，ＧＨＤが零に設定されるため、実質的に基本ゲインＧＢＡ，ＧＢＤは補正されず、基本ゲインＧＢＡ，ＧＢＤに基づき空気分圧ＰＰＡが求められることになる。 In the gain correction value calculation unit 153, the delay in the exhaust gas recirculation in the transient state increases as the inflow exhaust gas flow rate QEC in the cylinder increases, so that the response delay in the exhaust gas recirculation increases as the inflow exhaust gas flow rate QEC in the cylinder increases. The larger the value, the larger the gain correction values GHA and GHD are set as absolute values.
In the stopped state of exhaust gas recirculation where the inflow exhaust gas flow rate QEC in the cylinder is zero, the gain correction values GHA and GHD are set to zero, so that the basic gain GBA and GBD are not substantially corrected and the basic gain GBA, The air partial pressure PPA will be required based on GBD.

図８及び図９は、排ガス還流の応答遅れの特性を説明するためタイムチャートである。
ここで、図８は内燃機関１の加速状態における排ガス還流の応答特性を示し、図９は内燃機関１の減速状態における排ガス還流の応答特性を示す。
ＥＧＲ分圧ＰＰＥは、内燃機関１の過渡状態への移行からむだ時間が経過してから変化し始め、その後は２次の伝達関数で近似される特性で徐々に増減変化し、空気分圧ＰＰＡの過渡応答によりも遅れる。 8 and 9 are time charts for explaining the characteristics of the response delay of the exhaust gas reflux.
Here, FIG. 8 shows the response characteristics of the exhaust gas reflux in the accelerated state of the internal combustion engine 1, and FIG. 9 shows the response characteristics of the exhaust gas reflux in the decelerated state of the internal combustion engine 1.
The EGR partial pressure PPE begins to change after a lapse of time from the transition of the internal combustion engine 1 to the transient state, and then gradually increases or decreases with the characteristics approximated by the second-order transfer function, and the air partial pressure PPA It is also delayed by the transient response of.

ここで、ＥＧＲ分圧ＰＰＥの過渡応答におけるむだ時間は、排ガスが排気マニホールド１３から排ガス還流配管３１を介してスロットル弁５ａの下流の吸気管２に到達するまでのトラベルタイム（輸送時間）などによって生じる。
また、２次遅れは、排ガス還流配管３１と吸気管、排気管との配管径の差、排気管からの還流排ガスの分流、還流排ガスと空気との合流などによって生じる。 Here, the dead time in the transient response of the EGR partial pressure PPE depends on the travel time (transport time) from the exhaust manifold 13 to the intake pipe 2 downstream of the throttle valve 5a via the exhaust gas recirculation pipe 31. Occurs.
Further, the secondary delay is caused by the difference in pipe diameter between the exhaust gas recirculation pipe 31, the intake pipe, and the exhaust pipe, the diversion of the recirculated exhaust gas from the exhaust pipe, the merging of the recirculated exhaust gas and the air, and the like.

第１圧力勾配補正ゲイン演算部１５４は、基本ゲインＧＢＡ，ＧＢＤ及びゲイン補正値ＧＨＡ，ＧＨＤの情報を取得し、これらに基づき、空気分圧ＰＰＡの圧力勾配を補正するための圧力勾配補正ゲインＧＡＡ，ＧＡＤを求める処理部である。
第１圧力勾配補正ゲイン演算部１５４は、内燃機関１が加速状態であるとき、基本ゲインＧＢＡにゲイン補正値ＧＨＡの絶対値を加算した結果、換言すれば、基本ゲインＧＢＡをゲイン補正値ＧＨＡに応じて増加した値を、圧力勾配補正ゲインＧＡＡに設定する。
また、第１圧力勾配補正ゲイン演算部１５４は、内燃機関１が減速状態であるとき、基本ゲインＧＢＤにゲイン補正値ＧＨＤの絶対値を加算した結果、換言すれば、基本ゲインＧＢＤをゲイン補正値ＧＨＤに応じて増加した値を、圧力勾配補正ゲインＧＡＤに設定する。 The first pressure gradient correction gain calculation unit 154 acquires information on the basic gains GBA and GBD and the gain correction values GHA and GHD, and based on these, the pressure gradient correction gain GAA for correcting the pressure gradient of the air partial pressure PPA. , A processing unit that obtains GAD.
The first pressure gradient correction gain calculation unit 154 adds the absolute value of the gain correction value GHA to the basic gain GBA when the internal combustion engine 1 is in the accelerating state. As a result, in other words, the basic gain GBA is changed to the gain correction value GHA. The value increased accordingly is set in the pressure gradient correction gain GAA.
Further, the first pressure gradient correction gain calculation unit 154 adds the absolute value of the gain correction value GHD to the basic gain GBD when the internal combustion engine 1 is in the deceleration state. In other words, the basic gain GBD is the gain correction value. The value increased according to the GHD is set in the pressure gradient correction gain GAD.

一方、第２圧力勾配補正ゲイン演算部１５５は、基本ゲインＧＢＡ，ＧＢＤ及びゲイン補正値ＧＨＡ，ＧＨＤの情報を取得し、これらに基づき、ＥＧＲ分圧ＰＰＥの圧力勾配を補正するための圧力勾配補正ゲインＧＥＡ，ＧＥＤを求める処理部である。
第２圧力勾配補正ゲイン演算部１５５は、内燃機関１が加速状態であるとき、基本ゲインＧＢＡからゲイン補正値ＧＨＡの絶対値を減算した結果、換言すれば、基本ゲインＧＢＡをゲイン補正値ＧＨＡに応じて減少した値を、圧力勾配補正ゲインＧＥＡに設定する。
また、第２圧力勾配補正ゲイン演算部１５５は、内燃機関１が減速状態であるとき、基本ゲインＧＢＤからゲイン補正値ＧＨＤの絶対値を減算した結果、換言すれば、基本ゲインＧＢＤをゲイン補正値ＧＨＤに応じて減少した値を、圧力勾配補正ゲインＧＥＤに設定する。 On the other hand, the second pressure gradient correction gain calculation unit 155 acquires information on the basic gains GBA and GBD and the gain correction values GHA and GHD, and based on these, pressure gradient correction for correcting the pressure gradient of the EGR partial pressure PPE. This is a processing unit for obtaining gains GEA and GED.
The second pressure gradient correction gain calculation unit 155 subtracts the absolute value of the gain correction value GHA from the basic gain GBA when the internal combustion engine 1 is in the accelerating state. As a result, in other words, the basic gain GBA is changed to the gain correction value GHA. The value reduced accordingly is set in the pressure gradient correction gain GEA.
Further, the second pressure gradient correction gain calculation unit 155 subtracts the absolute value of the gain correction value GHD from the basic gain GBD when the internal combustion engine 1 is in the deceleration state. In other words, the basic gain GBD is the gain correction value. The value reduced according to the GHD is set in the pressure gradient correction gain GED.

このように、制御装置５０は、内燃機関１の過渡状態において、空気分圧ＰＰＡの過渡応答を補正するための圧力勾配補正ゲインＧＡＡ，ＧＡＤ、及び、ＥＧＲ分圧ＰＰＥの過渡応答を補正するための圧力勾配補正ゲインＧＥＡ，ＧＥＤを、基準とする基本ゲインＧＢＡ，ＧＢＤを排ガス還流の応答遅れに応じて補正して個別に設定する。
図１０は、内燃機関１の加速状態における、基本ゲインＧＢＡ、圧力勾配補正ゲインＧＡＡ、圧力勾配補正ゲインＧＥＡの相関、更に、空気分圧ＰＰＡ及びＥＧＲ分圧ＰＰＥの過渡応答補正（圧力勾配補正）の特性を説明するためのタイムチャートである。 As described above, in the transient state of the internal combustion engine 1, the control device 50 corrects the transient responses of the pressure gradient correction gains GAA and GAD for correcting the transient response of the air partial pressure PPA and the EGR partial pressure PPE. The pressure gradient correction gains GEA and GED are set individually by correcting the reference basic gains GBA and GBD according to the response delay of the exhaust gas recirculation.
FIG. 10 shows the correlation between the basic gain GBA, the pressure gradient correction gain GAA, and the pressure gradient correction gain GEA in the accelerated state of the internal combustion engine 1, and the transient response correction (pressure gradient correction) of the air partial pressure PPA and the EGR partial pressure PPE. It is a time chart for explaining the characteristic of.

基本ゲインＧＢＡ（ＧＢＤ）は、前述のように排ガス還流の停止状態（筒内流入排ガス流量ＱＥＣが零の状態）に適合する値であり、排ガス還流が停止されている内燃機関１の加速状態において、空気分圧ＰＰＡの圧力勾配を基本ゲインＧＢＡで補正することで、空気分圧ＰＰＡを実際値（センサ検出値）に近似させることができる。
一方、排ガス還流が実施される内燃機関１の加速状態において、排ガス還流の過渡応答に遅れが生じる分だけ、空気分圧の立ち上がり応答は排ガス還流の停止状態よりも速くなり、排ガス還流の過渡応答の遅れは、筒内流入排ガス流量ＱＥＣが多いときほど大きくなる。 The basic gain GBA (GBD) is a value conforming to the stopped state of exhaust gas recirculation (the state where the inflow exhaust gas flow rate QEC in the cylinder is zero) as described above, and is in the accelerated state of the internal combustion engine 1 in which the exhaust gas recirculation is stopped. By correcting the pressure gradient of the air partial pressure PPA with the basic gain GBA, the air partial pressure PPA can be approximated to the actual value (sensor detection value).
On the other hand, in the accelerated state of the internal combustion engine 1 in which the exhaust gas reflux is performed, the rising response of the air partial pressure becomes faster than the stopped state of the exhaust gas reflux due to the delay in the transient response of the exhaust gas reflux, and the transient response of the exhaust gas reflux occurs. The delay increases as the inflow exhaust gas flow rate QEC in the cylinder increases.

そこで、制御装置５０は、筒内流入排ガス流量ＱＥＣが多く排ガス還流の過渡応答の遅れが大きいときほどゲイン補正値ＧＨＡ（ＧＨＤ）をより大きな値に設定し、このゲイン補正値ＧＨＡで基本ゲインＧＢＡを増大補正した結果を、加速状態で空気分圧ＰＰＡの圧力勾配を補正するための圧力勾配補正ゲインＧＡＡに設定する。
そして、圧力勾配補正ゲインＧＡＡが大きくなるほど、第１の圧力勾配補正値ＰＧＣＡがより大きな値に設定され、空気分圧ＰＰＡの過渡応答を、排ガス還流の応答遅れに見合った実際の過渡応答に近似させる。 Therefore, the control device 50 sets the gain correction value GHA (GHD) to a larger value as the inflow exhaust gas flow rate QEC in the cylinder increases and the delay in the transient response of the exhaust gas return increases, and the basic gain GBA is set by this gain correction value GHA. The result of the increase correction is set to the pressure gradient correction gain GAA for correcting the pressure gradient of the air partial pressure PPA in the accelerated state.
Then, as the pressure gradient correction gain GAA becomes larger, the first pressure gradient correction value PGCA is set to a larger value, and the transient response of the air partial pressure PPA is approximated to the actual transient response commensurate with the response delay of the exhaust gas reflux. Let me.

一方、排ガス還流の過渡応答は、基本ゲインＧＢＡでの過渡応答よりも遅れるから、ゲイン補正値ＧＨＡで基本ゲインＧＢＡを減少補正した結果を、加速状態でＥＧＲ分圧ＰＰＥの圧力勾配を補正するための圧力勾配補正ゲインＧＥＡに設定する。
したがって、圧力勾配補正値演算部２００は、筒内流入排ガス流量ＱＥＣが多いときほど、第２の圧力勾配補正値ＰＧＣＥを減少させ、相対的に第１の圧力勾配補正値ＰＧＣＡを増加させることになる。 On the other hand, since the transient response of the exhaust gas recirculation is delayed from the transient response of the basic gain GBA, the result of reducing and correcting the basic gain GBA with the gain correction value GHA is used to correct the pressure gradient of the EGR partial pressure PPE in the accelerated state. Set to the pressure gradient correction gain GEA.
Therefore, the pressure gradient correction value calculation unit 200 reduces the second pressure gradient correction value PGCE and relatively increases the first pressure gradient correction value PGCA as the inflow exhaust gas flow rate QEC in the cylinder increases. Become.

つまり、基本ゲインＧＢＡ、空気分圧ＰＰＡ算出用の圧力勾配補正ゲインＧＡＡ、及び、ＥＧＲ分圧ＰＰＥ算出用の圧力勾配補正ゲインＧＥＡは、ＧＥＡ＜ＧＢＡ＜ＧＡＡの関係を満たす。
そして、基本ゲインＧＢＡと圧力勾配補正ゲインＧＡＡとの差、及び、基本ゲインＧＢＡと圧力勾配補正ゲインＧＥＡとの差は、筒内流入排ガス流量ＱＥＣが多いほど、換言すれば、排ガス還流の遅れが大きいときほど、より大きく設定される。
なお、内燃機関１の減速状態における、基本ゲインＧＢＤ、空気分圧ＰＰＡ算出用の圧力勾配補正ゲインＧＡＤ、ＥＧＲ分圧ＰＰＥ算出用の圧力勾配補正ゲインＧＥＤの特性も、同様である。 That is, the basic gain GBA, the pressure gradient correction gain GAA for calculating the air partial pressure PPA, and the pressure gradient correction gain GAA for calculating the EGR partial pressure PPE satisfy the relationship of GEA <GBA <GAA.
The difference between the basic gain GBA and the pressure gradient correction gain GAA and the difference between the basic gain GBA and the pressure gradient correction gain GEA is that the larger the inflow exhaust gas flow rate QEC in the cylinder, in other words, the delay in the exhaust gas recirculation. The larger the value, the larger the setting.
The characteristics of the basic gain GBD, the pressure gradient correction gain GAD for calculating the air partial pressure PPA, and the pressure gradient correction gain GED for calculating the EGR partial pressure PPE in the decelerated state of the internal combustion engine 1 are also the same.

上記のように、排ガス還流の遅れ分だけ空気分圧ＰＰＡの応答を速めることが制御装置５０における基本的な制御仕様である。
しかし、空気分圧ＰＰＡ、ＥＧＲ分圧ＰＰＥは絶対量が異なるため、単に基本ゲインＧＢＡ，ＧＢＤを筒内流入排ガス流量ＱＥＣに応じたゲイン補正値ＧＨＡ，ＧＨＤで増減させて、空気分圧ＰＰＡ及びＥＧＲ分圧ＰＰＥの過渡応答の補正に用いる構成では、最終的に求まる吸気管圧力（総ガス流量）に誤差が生じるおそれがある。 As described above, it is a basic control specification in the control device 50 to accelerate the response of the air partial pressure PPA by the delay of the exhaust gas recirculation.
However, since the absolute amounts of the air partial pressure PPA and the EGR partial pressure PPE are different, the basic gains GBA and GBD are simply increased or decreased by the gain correction values GHA and GHD according to the inflow exhaust gas flow rate QEC in the cylinder, and the air partial pressure PPA and In the configuration used for correcting the transient response of the EGR partial pressure PPE, there is a possibility that an error may occur in the finally obtained intake pipe pressure (total gas flow rate).

そこで、ゲイン補正値演算部１５３は、筒内流入排ガス流量ＱＥＣに応じたゲイン補正値ＧＨＡ，ＧＨＤの算出処理を基本としつつ、基本ゲインＧＢＡ，ＧＢＤの情報などを取得し、取得した基本ゲインＧＢＡ，ＧＢＤの情報に応じてゲイン補正値ＧＨＡ，ＧＨＤを変更することで、吸気管圧力（総ガス流量）の誤差を抑制することができる。
また、ゲイン補正値演算部１５３は、ゲイン補正値ＧＨＡ，ＧＨＤの算出処理において、ゲイン補正値ＧＨＡ，ＧＨＤに、排ガス還流の応答におけるむだ時間を考慮した補正項を含めることができる。 Therefore, the gain correction value calculation unit 153 acquires information on the basic gain GBA and GBD while basically calculating the gain correction values GHA and GHD according to the inflow exhaust gas flow rate QEC in the cylinder, and acquires the basic gain GBA. By changing the gain correction values GHA and GHD according to the GBD information, it is possible to suppress an error in the intake pipe pressure (total gas flow rate).
Further, the gain correction value calculation unit 153 can include a correction term in consideration of the dead time in the response of the exhaust gas recirculation in the gain correction values GHA and GHD in the calculation process of the gain correction values GHA and GHD.

図３のゲイン選択部１５６は、内燃機関１が定常状態であるか過渡状態（加速状態又は減速状態）であるかに応じて、定常状態用の圧力勾配補正ゲインと過渡状態用の圧力勾配補正ゲインとのいずれか一方を選択して出力する処理部である。
ゲイン選択部１５６は、第１ゲイン選択部１５６Ａと、第２ゲイン選択部１５６Ｂとを有する。 The gain selection unit 156 of FIG. 3 has a pressure gradient correction gain for a steady state and a pressure gradient correction for a transient state, depending on whether the internal combustion engine 1 is in a steady state or a transient state (acceleration state or deceleration state). This is a processing unit that selects and outputs either one of the gain.
The gain selection unit 156 includes a first gain selection unit 156A and a second gain selection unit 156B.

第１ゲイン選択部１５６Ａは、定常状態用ゲインＧＡＳ（ＧＡＳ＝1.0）と、第１圧力勾配補正ゲイン演算部１５４が算出した圧力勾配補正ゲインＧＡＡ又は圧力勾配補正ゲインＧＡＤを取得し、更に、加減速検出部１５１が出力する内燃機関１の運転状態判定信号を取得する。
そして、第１ゲイン選択部１５６Ａは、内燃機関１が定常状態であるとき、定常状態用ゲインＧＡＳを選択し、定常状態用ゲインＧＡＳの信号を、空気分圧ＰＰＡの演算に用いる圧力勾配補正ゲインの信号として出力する。 The first gain selection unit 156A acquires the steady state gain GAS (GAS = 1.0) and the pressure gradient correction gain GAA or the pressure gradient correction gain GAD calculated by the first pressure gradient correction gain calculation unit 154, and further adds the pressure gradient correction gain GAA or the pressure gradient correction gain GAD. The operation state determination signal of the internal combustion engine 1 output by the deceleration detection unit 151 is acquired.
Then, the first gain selection unit 156A selects the steady state gain GAS when the internal combustion engine 1 is in the steady state, and uses the signal of the steady state gain GAS to calculate the air partial pressure PPA. Is output as a signal of.

また、第１ゲイン選択部１５６Ａは、内燃機関１が加速状態であるとき、第１圧力勾配補正ゲイン演算部１５４が算出した圧力勾配補正ゲインＧＡＡを選択し、圧力勾配補正ゲインＧＡＡの信号を、空気分圧ＰＰＡの演算に用いる圧力勾配補正ゲインの信号として出力する。
更に、第１ゲイン選択部１５６Ａは、内燃機関１が減速状態であるとき、第１圧力勾配補正ゲイン演算部１５４が算出した圧力勾配補正ゲインＧＡＤを選択し、圧力勾配補正ゲインＧＡＤの信号を、空気分圧ＰＰＡの演算に用いる圧力勾配補正ゲインの信号として出力する。 Further, the first gain selection unit 156A selects the pressure gradient correction gain GAA calculated by the first pressure gradient correction gain calculation unit 154 when the internal combustion engine 1 is in the accelerating state, and transmits the signal of the pressure gradient correction gain GAA. It is output as a signal of the pressure gradient correction gain used in the calculation of the air partial pressure PPA.
Further, the first gain selection unit 156A selects the pressure gradient correction gain GAD calculated by the first pressure gradient correction gain calculation unit 154 when the internal combustion engine 1 is in the deceleration state, and transmits the signal of the pressure gradient correction gain GAD. It is output as a signal of the pressure gradient correction gain used in the calculation of the air partial pressure PPA.

第２ゲイン選択部１５６Ｂは、定常状態用ゲインＧＥＳ（ＧＥＳ＝1.0）と、第２圧力勾配補正ゲイン演算部１５５が算出した圧力勾配補正ゲインＧＥＡ又は圧力勾配補正ゲインＧＥＤを取得し、更に、加減速検出部１５１が出力する内燃機関１の運転状態判定信号を取得する。
そして、第２ゲイン選択部１５６Ｂは、内燃機関１が定常状態であるとき、定常状態用ゲインＧＥＳを選択し、定常状態用ゲインＧＥＳの信号を、ＥＧＲ分圧ＰＰＥの演算に用いる圧力勾配補正ゲインの信号として出力する。 The second gain selection unit 156B acquires the steady state gain GES (GES = 1.0) and the pressure gradient correction gain GEA or pressure gradient correction gain GED calculated by the second pressure gradient correction gain calculation unit 155, and further adds the pressure gradient correction gain GEA or the pressure gradient correction gain GED. The operation state determination signal of the internal combustion engine 1 output by the deceleration detection unit 151 is acquired.
Then, the second gain selection unit 156B selects the steady state gain GES when the internal combustion engine 1 is in the steady state, and uses the signal of the steady state gain GES for the calculation of the EGR partial pressure PPE pressure gradient correction gain. Is output as a signal of.

また、第２ゲイン選択部１５６Ｂは、内燃機関１が加速状態であるとき、第２圧力勾配補正ゲイン演算部１５５が算出した圧力勾配補正ゲインＧＥＡを選択し、圧力勾配補正ゲインＧＥＡの信号を、ＥＧＲ分圧ＰＰＥの演算に用いる圧力勾配補正ゲインの信号として出力する。
更に、第２ゲイン選択部１５６Ｂは、内燃機関１が減速状態であるとき、第２圧力勾配補正ゲイン演算部１５５が算出した圧力勾配補正ゲインＧＥＤを選択し、圧力勾配補正ゲインＧＥＤの信号を、ＥＧＲ分圧ＰＰＥの演算に用いる圧力勾配補正ゲインの信号として出力する。 Further, the second gain selection unit 156B selects the pressure gradient correction gain GEA calculated by the second pressure gradient correction gain calculation unit 155 when the internal combustion engine 1 is in the acceleration state, and transmits the signal of the pressure gradient correction gain GEA. It is output as a signal of the pressure gradient correction gain used in the calculation of the EGR partial pressure PPE.
Further, the second gain selection unit 156B selects the pressure gradient correction gain GED calculated by the second pressure gradient correction gain calculation unit 155 when the internal combustion engine 1 is in the deceleration state, and transmits the signal of the pressure gradient correction gain GED. It is output as a signal of the pressure gradient correction gain used in the calculation of the EGR partial pressure PPE.

第１圧力勾配補正値演算部１５７は、第１ゲイン選択部１５６Ａが出力する圧力勾配補正ゲインの信号を取得し、スロットル弁通過空気量ＱＡＦと筒内流入新気流量ＱＡＣの前回値ＱＡＣ-1との差分を、空気分圧ＰＰＡの変化分に変換するための第１の圧力勾配補正値ＰＧＣＡを求める。
第１圧力勾配補正値演算部１５７は、第１ゲイン選択部１５６Ａが出力する圧力勾配補正ゲインの信号の他、スロットル弁５ａと吸気弁６との間の吸気管２の容積、吸気温度ＴＡなどに基づき、第１の圧力勾配補正値ＰＧＣＡを求める。
そして、第１圧力勾配補正値演算部１５７は、第１ゲイン選択部１５６Ａが出力する圧力勾配補正ゲインが大きいほど、第１の圧力勾配補正値ＰＧＣＡをより大きな値に設定し、空気分圧ＰＰＡの過渡応答を速める。 The first pressure gradient correction value calculation unit 157 acquires the signal of the pressure gradient correction gain output by the first gain selection unit 156A, and the previous value QAC -1 of the throttle valve passing air amount QAF and the inflow fresh air flow rate QAC in the cylinder. The first pressure gradient correction value PGCA for converting the difference between the above and the pressure gradient into the change in the air partial pressure PPA is obtained.
In the first pressure gradient correction value calculation unit 157, in addition to the pressure gradient correction gain signal output by the first gain selection unit 156A, the volume of the intake pipe 2 between the throttle valve 5a and the intake valve 6, the intake temperature TA, etc. The first pressure gradient correction value PGCA is obtained based on the above.
Then, the first pressure gradient correction value calculation unit 157 sets the first pressure gradient correction value PGCA to a larger value as the pressure gradient correction gain output by the first gain selection unit 156A is larger, and the air partial pressure PPA Accelerate the transient response of.

第２圧力勾配補正値演算部１５８は、第２ゲイン選択部１５６Ｂが出力する圧力勾配補正ゲインの信号を取得し、排ガス還流量ＱＥＧＲと筒内流入排ガス流量ＱＥＣの前回値ＱＥＣ-1との差分を、ＥＧＲ分圧ＰＰＥの変化分に変換するための第２の圧力勾配補正値ＰＧＣＥを求める。
第２圧力勾配補正値演算部１５８は、第２ゲイン選択部１５６Ｂが出力する圧力勾配補正ゲインの信号の他、スロットル弁５ａと吸気弁６との間の吸気管２の容積、還流排ガスの温度などに基づき、第２の圧力勾配補正値ＰＧＣＥを求める。
そして、第２圧力勾配補正値演算部１５８は、第２ゲイン選択部１５６Ｂが出力する圧力勾配補正ゲインが大きいほど、第２の圧力勾配補正値ＰＧＣＥをより大きな値に設定し、ＥＧＲ分圧ＰＰＥの過渡応答を速める。 The second pressure gradient correction value calculation unit 158 acquires the signal of the pressure gradient correction gain output by the second gain selection unit 156B, and is the difference between the exhaust gas recirculation amount QEGR and the previous value QEC -1 of the inflow exhaust gas flow rate QEC in the cylinder. Is obtained as a second pressure gradient correction value PGCE for converting the EGR partial pressure PPE into a change.
The second pressure gradient correction value calculation unit 158 includes the pressure gradient correction gain signal output by the second gain selection unit 156B, the volume of the intake pipe 2 between the throttle valve 5a and the intake valve 6, and the temperature of the recirculated exhaust gas. The second pressure gradient correction value PGCE is obtained based on the above.
Then, the second pressure gradient correction value calculation unit 158 sets the second pressure gradient correction value PGC to a larger value as the pressure gradient correction gain output by the second gain selection unit 156B increases, and the EGR partial pressure PPE. Accelerate the transient response of.

前述の空気分圧演算部１０４は、第１圧力勾配補正値演算部１５７が求めた第１の圧力勾配補正値ＰＧＣＡに用い、前述の数式（１）にしたがって空気分圧ＰＰＡを算出する。
また、前述のＥＧＲ分圧演算部１０８は、第２圧力勾配補正値演算部１５８が求めた第２の圧力勾配補正値ＰＧＣＥを用い、前述の数式（２）にしたがってＥＧＲ分圧ＰＰＥを算出する。 The above-mentioned air partial pressure calculation unit 104 is used for the first pressure gradient correction value PGCA obtained by the first pressure gradient correction value calculation unit 157, and calculates the air partial pressure PPA according to the above-mentioned mathematical formula (1).
Further, the above-mentioned EGR partial pressure calculation unit 108 calculates the EGR partial pressure PPE according to the above-mentioned mathematical formula (2) by using the second pressure gradient correction value PGC obtained by the second pressure gradient correction value calculation unit 158. ..

上記の制御装置５０によると、排ガス還流の停止状態においては、空気分圧ＰＰＡの過渡応答を吸気管圧力センサ１７による検出値の変化に合わせるように適合された基本ゲインＧＢＡ，ＧＢＤに基づき、空気分圧ＰＰＡの過渡応答を補正する。
これにより、制御装置５０は、排ガス還流の停止状態での内燃機関１の過渡状態において、空気分圧ＰＰＡを精度良く推定し、空気分圧ＰＰＡに基づき筒内流入新気流量ＱＡＣを精度良く求めることができる。
したがって、制御装置５０は、排ガス還流の停止状態での内燃機関１の過渡状態において、高い精度で空燃比を制御でき、内燃機関１の燃焼性及び排ガス性状を良好に維持できる。 According to the above control device 50, in the stopped state of exhaust gas recirculation, the air is based on the basic gains GBA and GBD adapted to match the transient response of the air partial pressure PPA with the change of the detected value by the intake pipe pressure sensor 17. Correct the transient response of the partial pressure PPA.
As a result, the control device 50 accurately estimates the air partial pressure PPA in the transient state of the internal combustion engine 1 in the state where the exhaust gas recirculation is stopped, and accurately obtains the in-cylinder inflow fresh air flow rate QAC based on the air partial pressure PPA. be able to.
Therefore, the control device 50 can control the air-fuel ratio with high accuracy in the transient state of the internal combustion engine 1 in the state where the exhaust gas recirculation is stopped, and can maintain the combustibility and the exhaust gas properties of the internal combustion engine 1 well.

また、排ガス還流は、排ガス還流配管３１の分岐、合流や配管長などの影響によって、内燃機関１の過渡状態で遅れを生じ、係る排ガス還流の応答遅れは、排ガス還流量が多いときほど大きくなる。
そして、排ガス還流が行われる場合、空気分圧ＰＰＡの応答は、排ガス還流の応答が遅れる分だけ排ガス還流の停止状態よりも速まる。 Further, the exhaust gas recirculation causes a delay in the transient state of the internal combustion engine 1 due to the influence of the branching, merging, pipe length, etc. of the exhaust gas recirculation pipe 31, and the response delay of the exhaust gas recirculation becomes larger as the exhaust gas recirculation amount is larger. ..
When the exhaust gas reflux is performed, the response of the air partial pressure PPA is faster than the stopped state of the exhaust gas reflux by the amount that the response of the exhaust gas reflux is delayed.

そこで、制御装置５０は、排ガス還流の停止状態に適合された基本ゲインＧＢＡ，ＧＢＤを、筒内流入排ガス流量ＱＥＣが多く排ガス還流量の応答遅れが大きいときほど増大させ、係る増大補正後のゲインで空気分圧ＰＰＡの過渡応答を補正する。
これにより、制御装置５０は、排ガス還流の実施中における内燃機関１の過渡状態で、空気分圧ＰＰＡを精度良く求めることができる。 Therefore, the control device 50 increases the basic gains GBA and GBD adapted to the stopped state of the exhaust gas recirculation as the inflow exhaust gas flow rate QEC in the cylinder is large and the response delay of the exhaust gas recirculation amount is large, and the gain after the increase correction is increased. Corrects the transient response of the air partial pressure PPA with.
As a result, the control device 50 can accurately obtain the air partial pressure PPA in the transient state of the internal combustion engine 1 during the exhaust gas recirculation.

更に、排ガス還流が実施されるとき、制御装置５０は、排ガス還流の停止状態に適合された基本ゲインＧＢＡ，ＧＢＤを、排ガス還流量が多く排ガス還流の応答遅れが大きいときほど減少させ、係る減少補正後のゲインでＥＧＲ分圧ＰＰＥの過渡応答を補正する。
これにより、制御装置５０は、排ガス還流の実施中における内燃機関１の過渡状態で、排ガス還流の停止状態での実際の過渡応答を基準として、ＥＧＲ分圧ＰＰＥの過渡変化を精度良く求めることができる。 Further, when the exhaust gas recirculation is carried out, the control device 50 reduces the basic gains GBA and GBD adapted to the stopped state of the exhaust gas recirculation as the amount of the exhaust gas recirculation is large and the response delay of the exhaust gas recirculation is large. The corrected gain corrects the transient response of the EGR partial pressure PPE.
As a result, the control device 50 can accurately obtain the transient change of the EGR partial pressure PPE in the transient state of the internal combustion engine 1 during the execution of the exhaust gas recirculation, based on the actual transient response in the stopped state of the exhaust gas recirculation. it can.

したがって、排ガス還流の実施中における内燃機関１の過渡状態で、制御装置５０は、空気分圧ＰＰＡ及びＥＧＲ分圧ＰＰＥから吸気管圧力ＰＢＥを精度良く求めることができる。
更に、制御装置５０は、吸気管圧力ＰＢＥに基づきスロットル弁通過空気量ＱＡＦを求め、求めたスロットル弁通過空気量ＱＡＦに基づき筒内流入新気流量ＱＡＣを求めることで、実際の筒内流入新気流量に見合った燃料噴射量を精度良く設定できる。 Therefore, in the transient state of the internal combustion engine 1 during the exhaust gas recirculation, the control device 50 can accurately obtain the intake pipe pressure PBE from the air partial pressure PPA and the EGR partial pressure PPE.
Further, the control device 50 obtains the throttle valve passing air amount QAF based on the intake pipe pressure PBE, and obtains the in-cylinder inflow fresh air flow rate QAC based on the obtained throttle valve passing air amount QAF. The fuel injection amount can be set accurately according to the air flow rate.

ところで、基本ゲインＧＢＡ，ＧＢＤは、前述したように、排ガス還流の停止状態での空気分圧ＰＰＡが吸気管圧力センサ１７による検出値に合致するように適合される。
しかし、例えば内燃機関１の加速状態においては、空気がスロットル弁５ａ下流の吸気管２に充填されてから吸気管圧力センサ１７の出力が変化するため、吸気管圧力センサ１７の出力の変化には、スロットル弁５ａ下流の吸気管２の容積に応じた遅れが生じ、加速直後の空気充填の完了前は、吸気管圧力センサ１７の出力値と真値とにずれが生じる。 By the way, as described above, the basic gains GBA and GBD are adapted so that the air partial pressure PPA in the exhaust gas recirculation stopped state matches the value detected by the intake pipe pressure sensor 17.
However, for example, in the accelerated state of the internal combustion engine 1, the output of the intake pipe pressure sensor 17 changes after the air is filled in the intake pipe 2 downstream of the throttle valve 5a. , A delay occurs according to the volume of the intake pipe 2 downstream of the throttle valve 5a, and the output value and the true value of the intake pipe pressure sensor 17 deviate from each other before the completion of air filling immediately after acceleration.

同様に、内燃機関１の減速状態においては、スロットル弁５ａ下流の吸気管２に充填されていた空気が筒内に流出する遅れによって、吸気管圧力センサ１７の出力の変化に遅れが生じる。
このため、基本ゲインＧＢＡ，ＧＢＤを基準とする圧力勾配の補正では、過渡運転の開始直後における吸気管圧力センサ１７の応答遅れの間で、空気分圧ＰＰＡ及びＥＧＲ分圧ＰＰＥの推定誤差を生じるおそれがある。 Similarly, in the decelerated state of the internal combustion engine 1, the change in the output of the intake pipe pressure sensor 17 is delayed due to the delay in the outflow of the air filled in the intake pipe 2 downstream of the throttle valve 5a into the cylinder.
Therefore, in the correction of the pressure gradient based on the basic gains GBA and GBD, an estimation error of the air partial pressure PPA and the EGR partial pressure PPE occurs between the response delays of the intake pipe pressure sensor 17 immediately after the start of the transient operation. There is a risk.

上記の推定誤差の発生を抑制するため、制御装置５０を、基本ゲインＧＢＡ，ＧＢＤ及びゲイン補正値ＧＨＡ，ＧＨＤを、第１段階と第２段階とに分けて適用する構成とすることができる。
つまり、制御装置５０は、過渡初期であって吸気管圧力センサ１７の検出出力が応答遅れを生じる間の第１段階において、吸気管圧力センサ１７による検出値よりも推定値の応答を速めて真値に近づけるように適合された圧力勾配補正ゲインを適用する。
そして、制御装置５０は、吸気管圧力センサ１７の検出出力の応答遅れが解消した後の第２段階において、推定値を吸気管圧力センサ１７による検出値に合致させるように適合された圧力勾配補正ゲインを適用する。 In order to suppress the occurrence of the above estimation error, the control device 50 may be configured to apply the basic gain GBA, GBD and the gain correction values GHA, GHD separately in the first stage and the second stage.
That is, the control device 50 makes the response of the estimated value faster than the value detected by the intake pipe pressure sensor 17 in the first stage while the detection output of the intake pipe pressure sensor 17 causes a response delay in the transient initial stage. Apply a pressure gradient correction gain adapted to approach the value.
Then, the control device 50 adjusts the pressure gradient correction so as to match the estimated value with the value detected by the intake pipe pressure sensor 17 in the second stage after the response delay of the detection output of the intake pipe pressure sensor 17 is eliminated. Apply gain.

以下では、基本ゲインＧＢＡ，ＧＢＤ及びゲイン補正値ＧＨＡ，ＧＨＤを、第１段階と第２段階とに分けて適用するよう構成した制御装置５０を詳細に説明する。
図１１は、基本ゲインＧＢＡ，ＧＢＤ及びゲイン補正値ＧＨＡ，ＧＨＤを第１段階と第２段階とに分けて適用する構成とした制御装置５０における、圧力勾配補正値演算部２００による第１の圧力勾配補正値ＰＧＣＡ及び第２の圧力勾配補正値ＰＧＣＥの算出手順の一態様を示す機能ブロック図である。 Hereinafter, the control device 50 configured to apply the basic gains GBA and GBD and the gain correction values GHA and GHD separately to the first stage and the second stage will be described in detail.
FIG. 11 shows the first pressure by the pressure gradient correction value calculation unit 200 in the control device 50 having a configuration in which the basic gains GBA and GBD and the gain correction values GHA and GHD are applied separately to the first stage and the second stage. It is a functional block diagram which shows one aspect of the calculation procedure of the gradient correction value PGCA and the second pressure gradient correction value PGCE.

図１１において、開度変化演算部２０１は、スロットルセンサ５ｂが検出するスロットル開度ＴＶＯの現在値と一定時間前にスロットルセンサ５ｂが検出したスロットル開度ＴＶＯとの差分ΔＴＶＯを求める。
また、圧力変化演算部２０２は、吸気管圧力センサ１７が検出する吸気管圧力ＰＢの現在値と、吸気管圧力ＰＢの前回値と現在値に加重平均フィルタを掛けた値との差分ΔＰＢを求める。 In FIG. 11, the opening degree change calculation unit 201 obtains the difference ΔTVO between the current value of the throttle opening degree TVO detected by the throttle sensor 5b and the throttle opening degree TVO detected by the throttle sensor 5b a certain time ago.
Further, the pressure change calculation unit 202 obtains the difference ΔPB between the current value of the intake pipe pressure PB detected by the intake pipe pressure sensor 17 and the value obtained by applying a weighted average filter to the previous value and the current value of the intake pipe pressure PB. ..

加減速検出部２０３は、開度変化演算部２０１が求めた差分ΔＴＶＯ、及び、圧力変化演算部２０２が求めた差分ΔＰＢに関する信号を取得する。
そして、加減速検出部２０３は、差分ΔＴＶＯと加速判定用閾値ＴＨＯＡ１とを比較して内燃機関１が加速状態であるか否かを判断し、差分ΔＴＶＯと減速判定用閾値ＴＨＯＤ１とを比較して内燃機関１が減速状態であるか否かを判断する。 The acceleration / deceleration detection unit 203 acquires signals related to the difference ΔTVO obtained by the opening degree change calculation unit 201 and the difference ΔPB obtained by the pressure change calculation unit 202.
Then, the acceleration / deceleration detection unit 203 compares the difference ΔTVO with the acceleration determination threshold value THOA1 to determine whether or not the internal combustion engine 1 is in the acceleration state, and compares the difference ΔTVO with the deceleration determination threshold value THOD1. It is determined whether or not the internal combustion engine 1 is in the decelerated state.

また、加減速検出部２０３は、差分ΔＰＢと加速判定用閾値ＴＨＰＡ１とを比較して内燃機関１が加速状態であるか否かを判断し、差分ΔＰＢと減速判定用閾値ＴＨＰＤ１とを比較して内燃機関１が減速状態であるか否かを判断する。
ここで、加減速検出部２０３は、加速状態、減速状態の判定に用いる過渡判定閾値（ＴＨＯＡ１，ＴＨＯＤ１，ＴＨＰＡ１，ＴＨＰＤ１）を、吸気管圧力センサ１７が検出する吸気管圧力ＰＢなどの内燃機関１の負荷を代表する状態量に応じてそれぞれ個別に設定し、高負荷時ほど絶対値として大きな値に設定する（図１２参照）。 Further, the acceleration / deceleration detection unit 203 compares the difference ΔPB with the acceleration determination threshold THPA1 to determine whether or not the internal combustion engine 1 is in the acceleration state, and compares the difference ΔPB with the deceleration determination threshold THPD1. It is determined whether or not the internal combustion engine 1 is in the decelerated state.
Here, the acceleration / deceleration detection unit 203 detects the transient determination thresholds (THOA1, THOD1, THPA1, THPD1) used for determining the acceleration state and the deceleration state, and the intake pipe pressure sensor 17 detects the internal combustion engine 1 such as the intake pipe pressure PB. It is set individually according to the amount of state representing the load of, and is set to a larger value as an absolute value when the load is high (see FIG. 12).

そして、加減速検出部２０３は、差分ΔＴＶＯ又は差分ΔＰＢに基づき加速状態又は減速状態を判定すると、係る加減速判定の初回から所定時間ΔＴが経過するまでの間を、圧力勾配補正の第１段階（第１期間）に定める。
上記の所定時間ΔＴは、吸気管圧力センサ１７の応答遅れや排ガス還流の過渡応答におけるむだ時間などを考慮した時間であり、加減速検出部２０３は、所定時間ΔＴを、吸気管圧力センサ１７が検出する吸気管圧力ＰＢなどの内燃機関１の負荷を代表する状態量に応じて可変に設定することができる。 Then, when the acceleration / deceleration detection unit 203 determines the acceleration state or the deceleration state based on the difference ΔTVO or the difference ΔPB, the first stage of the pressure gradient correction is from the first time of the acceleration / deceleration determination to the elapse of the predetermined time ΔT. Established in (1st period).
The above-mentioned predetermined time ΔT is a time in consideration of the response delay of the intake pipe pressure sensor 17 and the dead time in the transient response of the exhaust gas recirculation, and the acceleration / deceleration detection unit 203 sets the predetermined time ΔT by the intake pipe pressure sensor 17. It can be variably set according to the state amount representing the load of the internal combustion engine 1 such as the intake pipe pressure PB to be detected.

加減速検出部２０３は、加減速判定の初回から所定時間ΔＴが経過すると、加減速判定に用いる閾値を、前述の閾値ＴＨＯＡ１，ＴＨＯＤ１，ＴＨＰＡ１，ＴＨＰＤ１から、第２段階での過渡判定に用いる閾値ＴＨＯＡ２，ＴＨＯＤ２，ＴＨＰＡ２，ＴＨＰＤ２に切り替えて、差分ΔＴＶＯ，ΔＰＢに基づく加減速判定を行う。
ここで、加減速検出部２０３は、差分ΔＴＶＯと閾値ＴＨＯＡ２，ＴＨＯＤ２との比較、又は、差分ΔＰＢと閾値ＴＨＰＡ２，ＴＨＰＤ２との比較によって加減速状態を判定すると、第１段階（第１期間）から第２段階（第２期間）への移行を判断する。 When the predetermined time ΔT elapses from the first acceleration / deceleration determination, the acceleration / deceleration detection unit 203 sets the threshold value used for the acceleration / deceleration determination from the above-mentioned threshold values THOA1, THOD1, THPA1, THPD1 to the threshold value used for the transient determination in the second stage. The acceleration / deceleration is determined based on the differences ΔTVO and ΔPB by switching to THOA2, THOD2, THPA2, and THPD2.
Here, when the acceleration / deceleration detection unit 203 determines the acceleration / deceleration state by comparing the difference ΔTVO with the threshold values THOA2 and THOD2 or comparing the difference ΔPB with the threshold values THPA2 and THPD2, the acceleration / deceleration detection unit 203 starts from the first stage (first period). Judge the transition to the second stage (second period).

そして、加減速検出部２０３は、差分ΔＴＶＯ，ΔＰＢと閾値ＴＨＯＡ２，ＴＨＯＤ２，ＴＨＰＡ２，ＴＨＰＤ２との比較に基づく加減速判定が不成立となるまで第２段階の継続を判断し、加減速判定の不成立になったとき、換言すれば、加減速判定が途絶えて定常判定したときに、第２段階の終了判定を行う。
なお、加減速検出部２０３は、閾値ＴＨＯＡ２，ＴＨＯＤ２，ＴＨＰＡ２，ＴＨＰＤ２を第１段階が終了してから一定時間だけ有効とし、加減速判定を行う。 Then, the acceleration / deceleration detection unit 203 determines the continuation of the second stage until the acceleration / deceleration determination based on the comparison between the difference ΔTVO, ΔPB and the threshold values THOA2, THOD2, THPA2, THPD2 is unsuccessful, and the acceleration / deceleration determination is unsuccessful. In other words, when the acceleration / deceleration determination is interrupted and a steady determination is made, the end determination of the second stage is performed.
The acceleration / deceleration detection unit 203 makes the threshold values THOA2, THOD2, THPA2, and THPD2 valid for a certain period of time after the first stage is completed, and makes an acceleration / deceleration determination.

また、加減速検出部２０３は、第２段階の判定に用いる閾値ＴＨＯＡ２，ＴＨＯＤ２，ＴＨＰＡ２，ＴＨＰＤ２を、第１段階の判定に用いる閾値ＴＨＯＡ１，ＴＨＯＤ１，ＴＨＰＡ１，ＴＨＰＤ１と同様に、吸気管圧力センサ１７が検出する吸気管圧力ＰＢなどの内燃機関１の負荷を代表する状態量に応じてそれぞれ個別に設定し、高負荷時ほど絶対値として大きな値に設定する（図１２参照）。
ここで、加減速検出部２０３は、第１段階の判定に用いる閾値ＴＨＯＡ１，ＴＨＯＤ１，ＴＨＰＡ１，ＴＨＰＤ１を、第２段階の判定に用いる閾値ＴＨＯＡ２，ＴＨＯＤ２，ＴＨＰＡ２，ＴＨＰＤ２よりも絶対値として大きな値に設定する。 Further, the acceleration / deceleration detection unit 203 uses the threshold values THOA2, THOD2, THPA2, and THPD2 used for the determination of the second stage as the intake pipe pressure sensor 17 in the same manner as the threshold values THOA1, THOD1, THPA1, and THPD1 used for the determination of the first stage. The pressure is set individually according to the state amount representing the load of the internal combustion engine 1 such as the intake pipe pressure PB detected by the engine, and is set to a larger absolute value as the load is higher (see FIG. 12).
Here, the acceleration / deceleration detection unit 203 sets the threshold values THOA1, THOD1, THPA1, and THPD1 used for the first-stage determination to a value larger than the threshold values THOA2, THOD2, THPA2, and THPD2 used for the second-stage determination as absolute values. Set.

これは、第１段階が過渡初期であって、単位時間当たりの圧力変化がその後の第２段階よりも大きいためである。
以上のようにして、加減速検出部２０３は、内燃機関１が加速状態又は減速状態であることを示す信号と、第１段階又は第２段階のいずれに該当するかを示す信号を出力する。 This is because the first stage is the initial transition and the pressure change per unit time is larger than that of the subsequent second stage.
As described above, the acceleration / deceleration detection unit 203 outputs a signal indicating that the internal combustion engine 1 is in the acceleration state or the deceleration state and a signal indicating whether the internal combustion engine 1 corresponds to the first stage or the second stage.

図１３は、内燃機関１の加速状態、減速状態それぞれにおける第１段階、第２段階を例示するタイムチャートである。
前述したように、内燃機関１の加速状態においては、スロットル弁５ａ下流の吸気管２へ空気充填が完了するまでの間で、吸気管圧力センサ１７の出力値が真値に対して位相遅れを生じる。 FIG. 13 is a time chart illustrating the first stage and the second stage in the acceleration state and the deceleration state of the internal combustion engine 1, respectively.
As described above, in the accelerated state of the internal combustion engine 1, the output value of the intake pipe pressure sensor 17 has a phase lag with respect to the true value until the intake pipe 2 downstream of the throttle valve 5a is completely filled with air. Occurs.

また、内燃機関１の減速状態においては、スロットル弁５ａ下流の吸気管２に充填されていた空気が筒内に流入するまでの間で、吸気管圧力センサ１７の出力値が真値に対して位相遅れを生じる。
そこで、制御装置５０は、吸気管圧力センサ１７の出力値が真値に対して位相遅れを生じる状態を第１段階として検知するとともに、前記位相遅れが解消した後の過渡状態を第２段階として検知する。
そして、制御装置５０は、第１段階と第２段階とで適用する基本ゲインＧＢＡ，ＧＢＤ及びゲイン補正値ＧＨＡ，ＧＨＤを個別に設定することで、吸気管圧力の推定誤差の発生を抑制する。 Further, in the decelerated state of the internal combustion engine 1, the output value of the intake pipe pressure sensor 17 is relative to the true value until the air filled in the intake pipe 2 downstream of the throttle valve 5a flows into the cylinder. It causes a phase lag.
Therefore, the control device 50 detects a state in which the output value of the intake pipe pressure sensor 17 causes a phase lag with respect to the true value as the first stage, and sets a transient state after the phase lag is eliminated as the second stage. Detect.
Then, the control device 50 suppresses the occurrence of an estimation error of the intake pipe pressure by individually setting the basic gains GBA and GBD and the gain correction values GHA and GHD applied in the first stage and the second stage.

図１１において、第１段階基本ゲイン演算部２０４は、加減速検出部２０３による加減速の判定結果を示す信号、機関回転速度ＮＥに関する信号、及び、吸気管圧力センサ１７が検出した吸気管圧力ＰＢに関する信号を取得する。
そして、第１段階基本ゲイン演算部２０４は、前述した基本ゲイン演算部１５２と同様にして、吸気管２内の推定圧力値の過渡応答を補正するための補正項（圧力勾配補正値）の第１段階基本値である基本ゲインＧＢＡ１，ＧＢＤ１を演算する。 In FIG. 11, the first-stage basic gain calculation unit 204 includes a signal indicating an acceleration / deceleration determination result by the acceleration / deceleration detection unit 203, a signal relating to the engine rotation speed NE, and an intake pipe pressure PB detected by the intake pipe pressure sensor 17. Get a signal about.
Then, the first-stage basic gain calculation unit 204 is the first of the correction terms (pressure gradient correction value) for correcting the transient response of the estimated pressure value in the intake pipe 2 in the same manner as the basic gain calculation unit 152 described above. The basic gains GBA1 and GBD1 which are the one-step basic values are calculated.

ここで、第１段階基本ゲイン演算部２０４における基本ゲインＧＢＡ１，ＧＢＤ１の演算特性は、吸気管圧力センサ１７の出力値が真値に対して位相遅れを生じる第１段階で、係る位相遅れを考慮して推定値を真値に近似させるように適合される。
また、第２段階基本ゲイン演算部２０５は、第１段階基本ゲイン演算部２０４と同様に、加減速検出部２０３による加減速の判定結果を示す信号、機関回転速度ＮＥに関する信号、及び、吸気管圧力センサ１７が検出した吸気管圧力ＰＢに関する信号を取得して、第２段階基本値である基本ゲインＧＢＡ２，ＧＢＤ２を演算する。 Here, the calculation characteristics of the basic gains GBA1 and GBD1 in the first-stage basic gain calculation unit 204 consider the phase lag in the first stage in which the output value of the intake pipe pressure sensor 17 causes a phase lag with respect to the true value. It is adapted to approximate the estimated value to the true value.
Further, the second-stage basic gain calculation unit 205, like the first-stage basic gain calculation unit 204, has a signal indicating the acceleration / deceleration determination result by the acceleration / deceleration detection unit 203, a signal relating to the engine rotation speed NE, and an intake pipe. The signal related to the intake pipe pressure PB detected by the pressure sensor 17 is acquired, and the basic gains GBA2 and GBD2, which are the second-stage basic values, are calculated.

ここで、第２段階基本ゲイン演算部２０５における基本ゲインＧＢＡ２，ＧＢＤ２の演算特性は、吸気管圧力センサ１７の出力値の真値に対する位相遅れが解消する第２段階において、吸気管２内の推定圧力値を吸気管圧力センサ１７の出力値に近似させるように適合される。
したがって、第１段階基本ゲイン演算部２０４が算出する基本ゲインＧＢＡ１，ＧＢＤ１は、第２段階基本ゲイン演算部２０５が算出する基本ゲインＧＢＡ２，ＧＢＤ２よりも大きく、吸気管圧力センサ１７の出力値が真値に対して位相遅れが生じる第１段階において、第２段階よりも圧力勾配補正を大きくして、吸気管２内の推定圧力値を真値に近似させる。 Here, the calculation characteristics of the basic gains GBA2 and GBD2 in the second-stage basic gain calculation unit 205 are estimated in the intake pipe 2 in the second stage in which the phase delay with respect to the true value of the output value of the intake pipe pressure sensor 17 is eliminated. The pressure value is adapted to approximate the output value of the intake pipe pressure sensor 17.
Therefore, the basic gains GBA1 and GBD1 calculated by the first-stage basic gain calculation unit 204 are larger than the basic gains GBA2 and GBD2 calculated by the second-stage basic gain calculation unit 205, and the output value of the intake pipe pressure sensor 17 is true. In the first stage where a phase delay occurs with respect to the value, the pressure gradient correction is made larger than in the second stage so that the estimated pressure value in the intake pipe 2 is approximated to the true value.

また、第１段階ゲイン補正値演算部２０６は、ゲイン補正値演算部１５３と同様に、筒内流入排ガス流量演算部１０９が求めた筒内流入排ガス流量ＱＥＣの演算値に基づき、第１段階補正値としてのゲイン補正値ＧＨＡ１，ＧＨＤ１を求める。
ここで、第１段階ゲイン補正値演算部２０６は、第１段階基本ゲイン演算部２０４が求めた基本ゲインＧＢＡ１，ＧＢＤ１の情報を取得し、取得した基本ゲインＧＢＡ１，ＧＢＤ１の情報に応じてゲイン補正値ＧＨＡ１，ＧＨＤ１を変更することで、吸気管圧力（総ガス流量）の誤差を抑制する。 Further, the first-stage gain correction value calculation unit 206, like the gain correction value calculation unit 153, performs the first-stage correction based on the calculated value of the in-cylinder inflow exhaust gas flow rate QEC obtained by the in-cylinder inflow exhaust gas flow rate calculation unit 109. The gain correction values GHA1 and GHD1 as values are obtained.
Here, the first-stage gain correction value calculation unit 206 acquires the information of the basic gains GBA1 and GBD1 obtained by the first-stage basic gain calculation unit 204, and gain correction according to the acquired information of the basic gains GBA1 and GBD1. By changing the values GHA1 and GHD1, the error of the intake pipe pressure (total gas flow rate) is suppressed.

第２段階ゲイン補正値演算部２０７は、ゲイン補正値演算部１５３と同様に、筒内流入排ガス流量演算部１０９が求めた筒内流入排ガス流量ＱＥＣの演算値に基づき、第２段階補正値としてのゲイン補正値ＧＨＡ２，ＧＨＤ２を求める。
ここで、第２段階ゲイン補正値演算部２０７は、第２段階基本ゲイン演算部２０５が求めた基本ゲインＧＢＡ２，ＧＢＤ２の情報を取得し、取得した基本ゲインＧＢＡ２，ＧＢＤ２の情報に応じてゲイン補正値ＧＨＡ２，ＧＨＤ２を変更することで、吸気管圧力（総ガス流量）の誤差を抑制する。 Similar to the gain correction value calculation unit 153, the second-stage gain correction value calculation unit 207 uses the in-cylinder inflow exhaust gas flow rate calculation unit 109 as the second-stage correction value based on the calculated value of the in-cylinder inflow exhaust gas flow rate QEC. Gain correction values GHA2 and GHD2 are obtained.
Here, the second-stage gain correction value calculation unit 207 acquires the information of the basic gains GBA2 and GBD2 obtained by the second-stage basic gain calculation unit 205, and gain correction according to the acquired information of the basic gains GBA2 and GBD2. By changing the values GHA2 and GHD2, the error of the intake pipe pressure (total gas flow rate) is suppressed.

第１段階空気分圧補正ゲイン演算部２０８は、内燃機関１が加速状態であるとき、第１段階基本ゲイン演算部２０４が算出した基本ゲインＧＢＡ１を第１段階ゲイン補正値演算部２０６が算出したゲイン補正値ＧＨＡ１で増大補正した結果を圧力勾配補正ゲインＧＡＡ１に設定する。
また、第１段階空気分圧補正ゲイン演算部２０８は、内燃機関１が減速状態であるとき、第１段階基本ゲイン演算部２０４が算出した基本ゲインＧＢＤ１を第１段階ゲイン補正値演算部２０６が算出したゲイン補正値ＧＨＤ１で増大補正した結果を、圧力勾配補正ゲインＧＡＤ１に設定する。 When the internal combustion engine 1 is in the acceleration state, the first-stage air partial pressure correction gain calculation unit 208 calculates the basic gain GBA1 calculated by the first-stage basic gain calculation unit 204 by the first-stage gain correction value calculation unit 206. The result of augmentation correction with the gain correction value GHA1 is set to the pressure gradient correction gain GAA1.
Further, in the first-stage air partial pressure correction gain calculation unit 208, when the internal combustion engine 1 is in the deceleration state, the first-stage gain correction value calculation unit 206 calculates the basic gain GBD1 calculated by the first-stage basic gain calculation unit 204. The result of augmentation correction with the calculated gain correction value GHD1 is set to the pressure gradient correction gain GAD1.

第１段階ＥＧＲ分圧補正ゲイン演算部２０９は、内燃機関１が加速状態であるとき、第１段階基本ゲイン演算部２０４が算出した基本ゲインＧＢＡ１を第１段階ゲイン補正値演算部２０６が算出したゲイン補正値ＧＨＡ１で減少補正した結果を、圧力勾配補正ゲインＧＥＡ１に設定する。
また、第１段階ＥＧＲ分圧補正ゲイン演算部２０９は、内燃機関１が減速状態であるとき、第１段階基本ゲイン演算部２０４が算出した基本ゲインＧＢＤ１を第１段階ゲイン補正値演算部２０６が算出したゲイン補正値ＧＨＤ１で減少補正した結果を圧力勾配補正ゲインＧＥＤ１に設定する。 When the internal combustion engine 1 is in the accelerated state, the first-stage EGR partial pressure correction gain calculation unit 209 calculates the basic gain GBA1 calculated by the first-stage basic gain calculation unit 204 by the first-stage gain correction value calculation unit 206. The result of reduction correction with the gain correction value GHA1 is set to the pressure gradient correction gain GEA1.
Further, in the first-stage EGR partial pressure correction gain calculation unit 209, when the internal combustion engine 1 is in the deceleration state, the first-stage gain correction value calculation unit 206 calculates the basic gain GBD1 calculated by the first-stage basic gain calculation unit 204. The result of reduction correction with the calculated gain correction value GHD1 is set to the pressure gradient correction gain GED1.

第２段階空気分圧補正ゲイン演算部２１０は、内燃機関１が加速状態であるとき、第２段階基本ゲイン演算部２０５が算出した基本ゲインＧＢＡ２を第２段階ゲイン補正値演算部２０７が算出したゲイン補正値ＧＨＡ２で増大補正した結果を圧力勾配補正ゲインＧＡＡ２に設定する。
また、第２段階空気分圧補正ゲイン演算部２１０は、内燃機関１が減速状態であるとき、第２段階基本ゲイン演算部２０５が算出した基本ゲインＧＢＤ２を第１段階ゲイン補正値演算部２０６が算出したゲイン補正値ＧＨＤ２で増大補正した結果を、圧力勾配補正ゲインＧＡＤ２に設定する。 When the internal combustion engine 1 is in the acceleration state, the second-stage air partial pressure correction gain calculation unit 210 calculates the basic gain GBA2 calculated by the second-stage basic gain calculation unit 205 by the second-stage gain correction value calculation unit 207. The result of augmentation correction with the gain correction value GHA2 is set to the pressure gradient correction gain GAA2.
Further, in the second-stage air partial pressure correction gain calculation unit 210, when the internal combustion engine 1 is in the deceleration state, the first-stage gain correction value calculation unit 206 calculates the basic gain GBD2 calculated by the second-stage basic gain calculation unit 205. The result of augmentation correction with the calculated gain correction value GHD2 is set in the pressure gradient correction gain GAD2.

第２段階ＥＧＲ分圧補正ゲイン演算部２１１は、内燃機関１が加速状態であるとき、第２段階基本ゲイン演算部２０５が算出した基本ゲインＧＢＡ２を第２段階ゲイン補正値演算部２０７が算出したゲイン補正値ＧＨＡ２で減少補正した結果を、圧力勾配補正ゲインＧＥＡ２に設定する。
また、第２段階ＥＧＲ分圧補正ゲイン演算部２１１は、内燃機関１が減速状態であるとき、第２段階基本ゲイン演算部２０５が算出した基本ゲインＧＢＤ２を第２段階ゲイン補正値演算部２０７が算出したゲイン補正値ＧＨＤ２で減少補正した結果を、圧力勾配補正ゲインＧＥＤ２に設定する。 In the second-stage EGR partial pressure correction gain calculation unit 211, when the internal combustion engine 1 is in the acceleration state, the second-stage gain correction value calculation unit 207 calculates the basic gain GBA2 calculated by the second-stage basic gain calculation unit 205. The result of reduction correction with the gain correction value GHA2 is set to the pressure gradient correction gain GEA2.
Further, in the second-stage EGR partial pressure correction gain calculation unit 211, when the internal combustion engine 1 is in the deceleration state, the second-stage gain correction value calculation unit 207 calculates the basic gain GBD2 calculated by the second-stage basic gain calculation unit 205. The result of reduction correction with the calculated gain correction value GHD2 is set to the pressure gradient correction gain GED2.

ゲイン選択部２１２は、空気分圧ＰＰＡの演算に用いるゲインを選択する第１ゲイン選択部２１２Ａと、ＥＧＲ分圧ＰＰＥの演算に用いるゲインを選択する第２ゲイン選択部２１２Ｂとを有する。
第１ゲイン選択部２１２Ａは、加減速検出部２０３が圧力勾配補正の第１段階を判定しているときは、第１段階空気分圧補正ゲイン演算部２０８が算出した圧力勾配補正ゲインＧＡＡ１又は圧力勾配補正ゲインＧＡＤ１を選択する。 The gain selection unit 212 includes a first gain selection unit 212A for selecting the gain used for calculating the air partial pressure PPA, and a second gain selection unit 212B for selecting the gain used for calculating the EGR partial pressure PPE.
When the acceleration / deceleration detection unit 203 determines the first stage of the pressure gradient correction, the first gain selection unit 212A determines the pressure gradient correction gain GAA1 or the pressure calculated by the first stage air partial pressure correction gain calculation unit 208. Select the gradient correction gain GAD1.

また、第１ゲイン選択部２１２Ａは、加減速検出部２０３が圧力勾配補正の第２段階を判定しているときは、第２段階空気分圧補正ゲイン演算部２１０が算出した圧力勾配補正ゲインＧＡＡ２又は圧力勾配補正ゲインＧＡＤ２を選択する。
そして、第１ゲイン選択部２１２Ａは、選択した値を最終的な圧力勾配補正ゲインＧＡＡ又は圧力勾配補正ゲインＧＡＤとして出力する。 Further, in the first gain selection unit 212A, when the acceleration / deceleration detection unit 203 determines the second stage of the pressure gradient correction, the pressure gradient correction gain GAA2 calculated by the second stage air partial pressure correction gain calculation unit 210 Alternatively, the pressure gradient correction gain GAD2 is selected.
Then, the first gain selection unit 212A outputs the selected value as the final pressure gradient correction gain GAA or the pressure gradient correction gain GAD.

第２ゲイン選択部２１２Ｂは、加減速検出部２０３が圧力勾配補正の第１段階を判定しているときは、第１段階ＥＧＲ分圧補正ゲイン演算部２０９が算出した圧力勾配補正ゲインＧＥＡ１又は圧力勾配補正ゲインＧＥＤ１を選択する。
また、第２ゲイン選択部２１２Ｂは、加減速検出部２０３が圧力勾配補正の第２段階を判定しているときは、第２段階ＥＧＲ分圧補正ゲイン演算部２１１が算出した圧力勾配補正ゲインＧＥＡ２又は圧力勾配補正ゲインＧＥＤ２を選択する。 When the acceleration / deceleration detection unit 203 determines the first stage of the pressure gradient correction, the second gain selection unit 212B is the pressure gradient correction gain GEA1 or the pressure calculated by the first stage EGR partial pressure correction gain calculation unit 209. Select the gradient correction gain GED1.
Further, in the second gain selection unit 212B, when the acceleration / deceleration detection unit 203 determines the second stage of the pressure gradient correction, the pressure gradient correction gain GEA2 calculated by the second stage EGR partial pressure correction gain calculation unit 211 Alternatively, the pressure gradient correction gain GED2 is selected.

そして、第２ゲイン選択部２１２Ｂは、選択した値を最終的な圧力勾配補正ゲインＧＥＡ又は圧力勾配補正ゲインＧＥＤとして出力する。
なお、図１１のゲイン選択部２１２において、定常状態用ゲインＧＡＳ（ＧＡＳ＝1.0）、ＧＥＳ（ＧＥＳ＝1.0）を選択して出力する構成の図示を省略したが、ゲイン選択部２１２は、ゲイン選択部１５６と同様に、内燃機関１の定常状態では定常状態用ゲインＧＡＳを選択して出力する機能を有する。 Then, the second gain selection unit 212B outputs the selected value as the final pressure gradient correction gain GEA or the pressure gradient correction gain GED.
Although the configuration in which the steady-state gain GAS (GAS = 1.0) and GES (GES = 1.0) are selected and output in the gain selection unit 212 of FIG. 11 is omitted, the gain selection unit 212 is used to select the gain. Similar to the unit 156, the internal combustion engine 1 has a function of selecting and outputting the steady state gain GAS in the steady state.

第１ゲイン選択部２１２Ａは、圧力勾配補正ゲインＧＡＡ又は圧力勾配補正ゲインＧＡＤに関する信号を、図３に示した第１圧力勾配補正値演算部１５７に出力し、第１圧力勾配補正値演算部１５７は、第１ゲイン選択部２１２Ａから取得した圧力勾配補正ゲインＧＡＡ又は圧力勾配補正ゲインＧＡＤに基づき、空気分圧ＰＰＡを求めるのに用いる第１の圧力勾配補正値ＰＧＣＡを求める。
また、第２ゲイン選択部２１２Ｂは、圧力勾配補正ゲインＧＥＡ又は圧力勾配補正ゲインＧＥＤに関する信号を、図３に示した第２圧力勾配補正値演算部１５８に出力し、第２圧力勾配補正値演算部１５８は、第２ゲイン選択部２１２Ｂから取得した圧力勾配補正ゲインＧＥＡ又は圧力勾配補正ゲインＧＥＤに基づき、ＥＧＲ分圧ＰＰＥを求めるのに用いる第２の圧力勾配補正値ＰＧＣＥを求める。 The first gain selection unit 212A outputs a signal relating to the pressure gradient correction gain GAA or the pressure gradient correction gain GAD to the first pressure gradient correction value calculation unit 157 shown in FIG. 3, and the first pressure gradient correction value calculation unit 157. Obtains the first pressure gradient correction value PGCA used to obtain the air partial pressure PPA based on the pressure gradient correction gain GAA or the pressure gradient correction gain GAD acquired from the first gain selection unit 212A.
Further, the second gain selection unit 212B outputs a signal relating to the pressure gradient correction gain GEA or the pressure gradient correction gain GED to the second pressure gradient correction value calculation unit 158 shown in FIG. 3, and calculates the second pressure gradient correction value. The unit 158 obtains the second pressure gradient correction value PGCE used to obtain the EGR partial pressure PPE based on the pressure gradient correction gain GEA or the pressure gradient correction gain GED acquired from the second gain selection unit 212B.

以上のように、制御装置５０は、第１の圧力勾配補正値ＰＧＣＡ，第２の圧力勾配補正値ＰＧＣＥの演算に用いる基本ゲインＧＢＡ，ＧＢＤ及びゲイン補正値ＧＨＡ，ＧＨＤを第１段階と第２段階とに分けて設定することで、過渡初期において吸気管圧力センサ１７の検出値が真値に対して位相遅れを生じる場合であっても、空気分圧ＰＰＡ及びＥＧＲ分圧ＰＰＥの推定精度が低下することを抑止できる。 As described above, the control device 50 sets the basic gains GBA and GBD and the gain correction values GHA and GHD used in the calculation of the first pressure gradient correction value PGCA and the second pressure gradient correction value PGCE in the first stage and the second stage. By setting the pressure separately for each stage, the estimation accuracy of the air partial pressure PPA and the EGR partial pressure PPE can be improved even when the detected value of the intake pipe pressure sensor 17 causes a phase delay with respect to the true value in the initial transient stage. It can be prevented from decreasing.

上記実施形態で説明した各技術的思想は、矛盾が生じない限りにおいて、適宜組み合わせて使用することができる。
また、好ましい実施形態を参照して本発明の内容を具体的に説明したが、本発明の基本的技術思想及び教示に基づいて、当業者であれば、種々の変形態様を採り得ることは自明である。 The technical ideas described in the above embodiments can be used in combination as appropriate as long as there is no contradiction.
In addition, although the contents of the present invention have been specifically described with reference to preferred embodiments, it is obvious that those skilled in the art can adopt various modifications based on the basic technical idea and teaching of the present invention. Is.

例えば、上記実施形態では、加速状態及び減速状態の双方で、図２及び図３に示した制御機能によって燃料噴射装置１０による燃料噴射量を制御するが、図２及び図３に示した制御機能による噴射量制御を加速状態と減速状態とのいずれか一方で実施する構成とすることができる。
また、図１に示した内燃機関１は過給機４を備えるが、本願発明に係る燃料噴射制御は、過給機４を備えない自然吸気機関に適用でき、過給機４を備えない自然吸気機関の場合、スロットル弁通過空気量演算部１０３は、大気圧と吸気管圧力ＰＢＥとの差に基づきスロットル弁通過空気量を求めることができる。 For example, in the above embodiment, the fuel injection amount by the fuel injection device 10 is controlled by the control functions shown in FIGS. 2 and 3 in both the acceleration state and the deceleration state, but the control function shown in FIGS. 2 and 3 is used. The injection amount control by the above can be performed in either the acceleration state or the deceleration state.
Further, although the internal combustion engine 1 shown in FIG. 1 is provided with a supercharger 4, the fuel injection control according to the present invention can be applied to a naturally aspirated engine not provided with the supercharger 4, and is not provided with the supercharger 4. In the case of an intake engine, the throttle valve passing air amount calculation unit 103 can obtain the throttle valve passing air amount based on the difference between the atmospheric pressure and the intake pipe pressure PBE.

また、燃料噴射装置１０が吸気ポート内に燃料を噴射する所謂ポート噴射式内燃機関とすることができる。
また、制御装置５０は、排ガス還流の停止状態において、吸気管圧力センサ１７による吸気管圧力ＰＢの検出結果と、空気分圧演算部１０４による空気分圧ＰＰＡの推定結果とを比較して、基本ゲインＧＢＡ，ＧＢＤを学習することができる。 Further, the fuel injection device 10 can be a so-called port injection type internal combustion engine that injects fuel into the intake port.
Further, the control device 50 basically compares the detection result of the intake pipe pressure PB by the intake pipe pressure sensor 17 with the estimation result of the air partial pressure PPA by the air partial pressure calculation unit 104 in the stopped state of the exhaust gas recirculation. Gain GBA and GBD can be learned.

また、制御装置５０は、吸気管圧力を変数とするマップの検索において、吸気管圧力センサ１７による吸気管圧力の検出値を用いるが、各マップの適合が完了している場合は、マップ検索に吸気管圧力の推定値を用いることができる。 Further, the control device 50 uses the detection value of the intake pipe pressure by the intake pipe pressure sensor 17 in the search of the map in which the intake pipe pressure is a variable, but when the matching of each map is completed, the map search is performed. An estimate of the intake pipe pressure can be used.

１…内燃機関、２…吸気管、２ｂ…吸気コレクタ、５…電制スロットル装置、６…吸気弁、１０…燃料噴射装置、１３…排気マニホールド、３０…排ガス還流装置、３１…排ガス還流配管、３２…排ガス還流制御弁、５０…制御装置、１０１…吸入空気量検出部、１０２…圧力推定部、１０３…スロットル弁通過空気量演算部、１０４…空気分圧演算部、１０５…筒内流入新気流量演算部、１０６…基本燃料噴射量演算部、１０７…排ガス還流量演算部、１０８…ＥＧＲ分圧演算部、１０９…筒内流入排ガス流量演算部、１１０…吸気管圧力演算部、２００…圧力勾配補正値演算部 1 ... Internal combustion engine, 2 ... Intake pipe, 2b ... Intake collector, 5 ... Electronically controlled throttle device, 6 ... Intake valve, 10 ... Fuel injection device, 13 ... Exhaust gas manifold, 30 ... Exhaust gas recirculation device, 31 ... Exhaust gas recirculation pipe, 32 ... Exhaust gas recirculation control valve, 50 ... Control device, 101 ... Intake air amount detection unit, 102 ... Pressure estimation unit, 103 ... Throttle valve passing air amount calculation unit, 104 ... Air partial pressure calculation unit, 105 ... In-cylinder inflow new Air flow calculation unit, 106 ... Basic fuel injection amount calculation unit, 107 ... Exhaust gas recirculation amount calculation unit, 108 ... EGR partial pressure calculation unit, 109 ... Inflow exhaust gas flow rate calculation unit, 110 ... Intake pipe pressure calculation unit, 200 ... Pressure gradient correction value calculation unit

Claims (10)

スロットル弁の下流の吸気管に燃焼後の排ガスを還流させる排ガス還流配管と、
前記排ガス還流配管を介して前記吸気管に還流される排ガス還流量を制御する排ガス還流制御弁と、
燃料噴射装置と、
を備える内燃機関に適用され、前記燃料噴射装置による燃料噴射を制御する制御装置であって、
前記スロットル弁を通過する空気量であるスロットル弁通過空気量と前記内燃機関の筒内に流入する新気流量である筒内流入新気流量と第１の圧力勾配補正値とに基づき、前記吸気管における空気分圧を求める空気分圧演算部と、
前記排ガス還流制御弁を介して前記吸気管に還流される排ガス還流量と前記内燃機関の筒内に流入する排ガス流量である筒内流入排ガス流量と第２の圧力勾配補正値とに基づき、前記吸気管における還流排ガス分圧を求める還流排ガス分圧演算部と、
前記空気分圧及び前記還流排ガス分圧に基づき吸気管圧力を求める吸気管圧力演算部と、
前記吸気管圧力と前記スロットル弁の上流の圧力と前記スロットル弁の開度とに基づき前記スロットル弁通過空気量を求めるスロットル弁通過空気量演算部と、
前記空気分圧に基づき前記筒内流入新気流量を求める筒内流入新気流量演算部と、
前記筒内流入新気流量に基づき前記燃料噴射装置による燃料噴射量を演算する燃料噴射量演算部と、
を有する、内燃機関の制御装置。 An exhaust gas recirculation pipe that recirculates the exhaust gas after combustion to the intake pipe downstream of the throttle valve,
An exhaust gas recirculation control valve that controls the amount of exhaust gas recirculated to the intake pipe via the exhaust gas recirculation pipe.
Fuel injection device and
A control device that is applied to an internal combustion engine and controls fuel injection by the fuel injection device.
The intake air is based on the amount of air passing through the throttle valve, which is the amount of air passing through the throttle valve, the inflow fresh air flow rate, which is the fresh air flow rate flowing into the cylinder of the internal combustion engine, and the first pressure gradient correction value. The air partial pressure calculation unit that obtains the air partial pressure in the pipe,
Based on the exhaust gas recirculation amount returned to the intake pipe via the exhaust gas recirculation control valve, the in-cylinder inflow exhaust gas flow rate which is the exhaust gas flow rate flowing into the cylinder of the internal combustion engine, and the second pressure gradient correction value. A recirculated exhaust gas partial pressure calculation unit that obtains the recirculated exhaust gas partial pressure in the intake pipe,
An intake pipe pressure calculation unit that obtains an intake pipe pressure based on the air partial pressure and the reflux exhaust gas partial pressure,
A throttle valve passing air amount calculation unit that obtains the throttle valve passing air amount based on the intake pipe pressure, the pressure upstream of the throttle valve, and the opening degree of the throttle valve.
In-cylinder inflow fresh air flow rate calculation unit for obtaining the in-cylinder inflow fresh air flow rate based on the air partial pressure, and
A fuel injection amount calculation unit that calculates the fuel injection amount by the fuel injection device based on the inflow fresh air flow rate in the cylinder, and
A control device for an internal combustion engine. 前記空気分圧演算部は、前記スロットル弁通過空気量と前記筒内流入新気流量との差分、及び、前記第１の圧力勾配補正値に基づき、前記空気分圧の変化分を求め、
前記還流排ガス分圧演算部は、前記排ガス還流量と前記筒内流入排ガス流量との差分、及び、前記第２の圧力勾配補正値に基づき、前記還流排ガス分圧の変化分を求める、
請求項１記載の内燃機関の制御装置。 The air partial pressure calculation unit obtains the change in the air partial pressure based on the difference between the amount of air passing through the throttle valve and the inflow fresh air flow rate in the cylinder and the first pressure gradient correction value.
The recirculated exhaust gas partial pressure calculation unit obtains a change in the recirculated exhaust gas partial pressure based on the difference between the exhaust gas recirculation amount and the inflow exhaust gas flow rate in the cylinder and the second pressure gradient correction value.
The control device for an internal combustion engine according to claim 1. 前記第１の圧力勾配補正値を前記第２の圧力勾配補正値より大きい値に設定する、
圧力勾配補正値演算部を更に有する、
請求項１記載の内燃機関の制御装置。 The first pressure gradient correction value is set to a value larger than the second pressure gradient correction value.
It also has a pressure gradient correction value calculation unit.
The control device for an internal combustion engine according to claim 1. 前記圧力勾配補正値演算部は、
前記筒内流入排ガス流量が多いときほど、前記第２の圧力勾配補正値を減少させ、相対的に前記第１の圧力勾配補正値を増加させる、
請求項３記載の内燃機関の制御装置。 The pressure gradient correction value calculation unit
As the inflow exhaust gas flow rate in the cylinder increases, the second pressure gradient correction value is decreased, and the first pressure gradient correction value is relatively increased.
The control device for an internal combustion engine according to claim 3. 前記圧力勾配補正値演算部は、
前記内燃機関の運転状態に基づき圧力勾配補正値の基本値を求め、
前記還流排ガス分圧に基づき求められた前記筒内流入排ガス流量に基づき補正値を求め、
前記基本値を前記補正値に応じて増加した値に基づき前記第１の圧力勾配補正値を求め、
前記基本値を前記補正値に応じて減少した値に基づき前記第２の圧力勾配補正値を求める、
請求項３記載の内燃機関の制御装置。 The pressure gradient correction value calculation unit
The basic value of the pressure gradient correction value is obtained based on the operating state of the internal combustion engine.
A correction value was obtained based on the inflow exhaust gas flow rate in the cylinder obtained based on the partial pressure of the reflux exhaust gas.
The first pressure gradient correction value is obtained based on the value obtained by increasing the basic value according to the correction value.
The second pressure gradient correction value is obtained based on the value obtained by reducing the basic value according to the correction value.
The control device for an internal combustion engine according to claim 3. 前記圧力勾配補正値演算部は、
前記内燃機関の回転速度が高いほど前記基本値を大きくし、
前記筒内流入排ガス流量が多いほど前記補正値を大きくする、
請求項５記載の内燃機関の制御装置。 The pressure gradient correction value calculation unit
The higher the rotation speed of the internal combustion engine, the larger the basic value.
The larger the inflow exhaust gas flow rate in the cylinder, the larger the correction value.
The control device for an internal combustion engine according to claim 5. 前記圧力勾配補正値演算部は、
前記基本値及び前記補正値を、前記内燃機関の加速状態と減速状態とで個別に設定する、
請求項５記載の内燃機関の制御装置。 The pressure gradient correction value calculation unit
The basic value and the correction value are individually set for the acceleration state and the deceleration state of the internal combustion engine.
The control device for an internal combustion engine according to claim 5. 前記圧力勾配補正値演算部は、
前記基本値として第１段階基本値及び第２段階基本値を求め、
前記補正値として第１段階補正値及び第２段階補正値を求め、
前記内燃機関の過渡状態において、前記第１の圧力勾配補正値及び前記第２の圧力勾配補正値を求めるのに用いる前記基本値及び前記補正値を、前記第１段階基本値及び前記第１段階補正値から前記第２段階基本値及び前記第２段階補正値に切り替える、
請求項５記載の内燃機関の制御装置。 The pressure gradient correction value calculation unit
Obtain the first-stage basic value and the second-stage basic value as the basic values,
The first-stage correction value and the second-stage correction value are obtained as the correction values.
In the transient state of the internal combustion engine, the basic value and the correction value used to obtain the first pressure gradient correction value and the second pressure gradient correction value are the first step basic value and the first step. Switching from the correction value to the second-stage basic value and the second-stage correction value,
The control device for an internal combustion engine according to claim 5. 前記圧力勾配補正値演算部は、
前記内燃機関の過渡状態になってから所定時間が経過したときに、前記第１段階基本値及び前記第１段階補正値から前記第２段階基本値及び前記第２段階補正値に切り替える、
請求項８記載の内燃機関の制御装置。 The pressure gradient correction value calculation unit
When a predetermined time elapses after the transition state of the internal combustion engine, the first-stage basic value and the first-stage correction value are switched to the second-stage basic value and the second-stage correction value.
The control device for an internal combustion engine according to claim 8. 前記圧力勾配補正値演算部は、
前記内燃機関の過渡状態になってから前記所定時間が経過した後は、過渡状態の判定閾値を前記所定時間が経過する前よりも小さい値に変更し、
変更後の前記判定閾値に基づき前記内燃機関の過渡状態が判定される状態で、前記第２段階基本値及び前記第２段階補正値に基づき、前記第１の圧力勾配補正値及び前記第２の圧力勾配補正値を求める、
請求項９記載の内燃機関の制御装置。 The pressure gradient correction value calculation unit
After the predetermined time has elapsed since the internal combustion engine was in the transient state, the threshold value for determining the transient state is changed to a value smaller than that before the predetermined time has elapsed.
In a state where the transient state of the internal combustion engine is determined based on the changed determination threshold value, the first pressure gradient correction value and the second stage correction value are based on the second stage basic value and the second stage correction value. Find the pressure gradient correction value,
The control device for an internal combustion engine according to claim 9.
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