JP4170773B2 - Fuel injection timing control device for in-cylinder injection type engine - Google Patents

Description

この式１３は、液体燃料がピストン頂面６ａに到達している時の関係を表している。尚、θ(ｔ)はクランク角の時間変化、Ｖｐ（ＮＥ，θ(ｔ)）はピストン６の移動速度、Ｖｓは噴射燃料先端速度、αは噴射角（図１）である。又、噴射燃料気化必要時間（燃料噴射時から液体燃料が完全に気化するまでの時間）ｔｖはエンジン冷却水温ＴＨＷの関数で与えられる。
【０２３６】
（ｈ）．前記実施の形態１では、ＥＣＵ４は、ステップＳ１０２にて読み込んだデータから最終的に補正値θｓｍを求める計算を順次実行した。この代わりに、補正値θｓｍを求めるために用いられている上記データをパラメータとするマップを、予め実施の形態１にて説明した計算により求めてＥＣＵ４内のＲＯＭなどのメモリに格納しておいても良い。したがって補正値θｓｍが必要な場合には、ステップＳ１０２で読み込んだデータに基づいて上記マップから補正値θｓｍを求めることになる。吸気ポート吹き返しスモーク量Ｓｍｒｅｔについても同様に実施の形態１にて説明した計算によりマップとして予め構成してＲＯＭなどのメモリに格納しておき、このマップからステップＳ１０２にて読み込んだデータに基づいて吸気ポート吹き返しスモーク量Ｓｍｒｅｔを求めても良い。
【０２３７】
又、「θａｉｎｊ＋θｓｍ」の値自体を、ステップＳ１０２にて読み込んだデータをパラメータとするマップとして予め実施の形態１にて説明した計算にて求めてＥＣＵ４内のＲＯＭなどのメモリに格納しておいても良い。したがって燃料噴射時期θｉｎｊが必要な場合には、ステップＳ１０２で読み込んだデータに基づいて上記マップから燃料噴射時期θｉｎｊを求めることになる。
【０２３８】
前記実施の形態２においても、上述したごとく補正値θｐｔｎ、スモーク量Ｓｍｐｔｎあるいは燃料噴射時期θｉｎｊを実施の形態２にて説明した計算によりマップ化して、このマップからステップＳ２０２にて読み込んだデータに基づいて求めても良い。同様に補正値θｐｔｎと補正値θｌｄとを一つにした補正値マップを、予め補正値θｐｔｎ及び補正値θｌｄを求めるために用いられている各データをパラメータとして実施の形態２にて説明した計算により求めてＥＣＵ４内のＲＯＭなどのメモリに格納しておいても良い。そして必要時にステップＳ２０２にて読み込んだデータに基づいて補正値θｐｔｎと補正値θｌｄとを一つにした補正値を上記マップから求めて用いても良い。
【０２３９】
前記実施の形態３においても、上述したごとく補正値θｔｈｗ、θｎｅ、θｔｈｗ＋θｎｅ、あるいは燃料噴射時期θｉｎｊを実施の形態３にて説明した計算によりマップ化して、このマップからステップＳ３０２にて読み込んだデータに基づいて求めても良い。
【０２４０】
前記実施の形態４，５，６においても、上述したごとく補正値θｏｖｒあるいは燃料噴射時期θｉｎｊを実施の形態４，５，６にて説明した計算によりマップ化して、このマップからステップＳ４０２，Ｓ６０２にて読み込んだデータに基づいて求めても良い。
【０２４１】
上述したごとくマップ処理により各実施の形態を構成することで、ＥＣＵに対する負荷を抑制できる。このためＥＣＵに用いるＣＰＵなどの演算装置に安価なものを利用できたり、処理を迅速化することができる。
【図面の簡単な説明】
【図１】実施の形態１の筒内噴射式エンジン及びＥＣＵの概略系統図。
【図２】上記ＥＣＵが実行する燃料噴射時期制御処理のフローチャート。
【図３】実施の形態１の燃料噴射時期補正処理を説明するための燃料噴射時期とスモーク濃度Ｓｍｄｔｙとの関係を示すグラフ。
【図４】実施の形態２の燃料噴射時期制御処理のフローチャート。
【図５】燃料圧力Ｐｆの違いによる噴射燃料とピストン頂面との位置関係を示すタイミングチャート。
【図６】エンジン冷却水温ＴＨＷの違いによる噴射燃料とピストン頂面との位置関係を示すタイミングチャート。
【図７】エンジン回転数ＮＥの違いによる噴射燃料とピストン頂面との位置関係を示すタイミングチャート。
【図８】燃料噴射モード毎に基本燃料噴射時期θａｉｎｊと燃料圧力Ｐｆとに基づいて基本到達量Ｆ０を求めるマップの構成説明図。
【図９】燃料噴射モード毎に基本燃料噴射時期θａｉｎｊとエンジン冷却水温ＴＨＷとに基づいて温度補正係数ｋｔｈｗを求めるマップの構成説明図。
【図１０】燃料噴射モード毎に基本燃料噴射時期θａｉｎｊとエンジン回転数ＮＥとに基づいて回転数補正係数ｋｎｅを求めるマップの構成説明図。
【図１１】燃料噴射時間Ｔｉｎｊから噴射時間補正係数ｋｉｎｊを求めるマップの構成説明図。
【図１２】基本燃料噴射時期θａｉｎｊとエンジン冷却水温ＴＨＷとに基づいて燃料気化量Ｆｏｕｔを求めるマップの構成説明図。
【図１３】実施の形態２の燃料噴射時期補正処理を説明するための燃料噴射時期とスモーク量Ｓｍｐｔｎとの関係を示すグラフ。
【図１４】走行距離Ｌｄに基づいて補正値θｌｄを算出するマップの構成説明図。
【図１５】実施の形態３の燃料噴射時期制御処理のフローチャート。
【図１６】燃料噴射モード毎に基本燃料噴射時期θａｉｎｊとエンジン冷却水温ＴＨＷとに基づいて補正値θｔｈｗを求めるマップの構成説明図。
【図１７】燃料噴射モード毎に基本燃料噴射時期θａｉｎｊとエンジン回転数ＮＥとに基づいて補正値θｎｅを求めるマップの構成説明図。
【図１８】実施の形態３の燃料噴射時期補正処理を説明するための燃料噴射時期とスモーク濃度Ｓｍｄｔｙとの関係を示すグラフ。
【図１９】実施の形態４の燃料噴射時期制御処理のフローチャート。
【図２０】実施の形態４の燃料噴射時期補正減衰処理のフローチャート。
【図２１】燃料噴射モード毎に基本燃料噴射時期θａｉｎｊとバルブオーバラップ期間Ｌｏｖｒとに基づいて燃料噴射時期補正値θｏｖｒを求めるマップの構成説明図。
【図２２】実施の形態５の燃料噴射時期補正減衰処理のフローチャート。
【図２３】実施の形態６の燃料噴射時期制御処理のフローチャート。
【図２４】実施の形態６の燃料噴射時期補正減衰処理のフローチャート。
【図２５】燃料噴射モード毎に基本燃料噴射時期θａｉｎｊとバルブオーバラップ期間Ｌｏｖｒとに基づいて補正量θｙを求めるマップの構成説明図。
【符号の説明】
２…エンジン、２ａ…吸気バルブ、２ｂ…排気バルブ、４…ＥＣＵ、６…ピストン、６ａ…ピストン頂面、１０…燃焼室、１２…燃料噴射弁、１４…点火プラグ、１６…吸気ポート、２０…吸気通路、２２…サージタンク、２４…モータ、２６…スロットルバルブ、２８…スロットル開度センサ、３０…吸入空気量センサ、３２…排気ポート、３６…排気通路、３８…排気浄化触媒、４０…燃料圧力センサ、４２…吸気カム、４３…吸気用可変動弁機構、４３ａ…ストロークセンサ、４４…排気カム、４５…排気用可変動弁機構、４５ａ…ストロークセンサ、４６…アクセルペダル、４８…アクセル開度センサ、５０…エンジン回転数センサ、５２…基準クランク角センサ、５４…冷却水温センサ、５６…空燃比センサ、５８…走行距離メータ。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel injection timing control device for a direct injection type engine.
[0002]
[Prior art]
Since the direct injection engine injects fuel into the combustion chamber, depending on the operating state of the engine and the position of the piston, the fuel injected from the fuel injection valve reaches the top surface of the piston in a liquid state and reaches the top surface of the piston It may adhere to a film. If such liquid fuel adheres, incomplete combustion of the fuel occurs on the top surface of the piston, which may increase the amount of smoke in the burnt gas (meaning the gas after combustion).
[0003]
Furthermore, when the amount of smoke increases, when the intake valve is opened in the next intake stroke, the intake system may be contaminated by smoke depending on the degree of return of burned gas.
[0004]
As a technique for suppressing the smoke amount and preventing smoke pollution of the intake system, a technique for suppressing the generation of smoke by retarding the fuel injection timing in the intake stroke when the engine is cold (for example, patents) is known. Reference 1).
[0005]
[Patent Document 1]
JP-A-10-176562 (5th page, FIG. 5)
[0006]
[Problems to be solved by the invention]
In the prior art described above, the correction is not limited to the correction of the fuel injection timing in the intake stroke, and no measures are taken with respect to the amount of smoke and the smoke pollution caused by the fuel injection in the compression stroke of the in-cylinder injection type engine. For this reason, regarding the suppression of smoke amount and smoke pollution, it is unclear what method is effective for fuel injection in the compression stroke of the in-cylinder injection type engine.
[0007]
The present invention effectively suppresses the smoke amount and smoke contamination with respect to the fuel injection in the compression stroke in the cylinder injection type engine, and appropriately takes the intake system in both the fuel injection in the compression stroke and the intake stroke. The purpose is to suppress smoke pollution.
[0008]
[Means for Solving the Problems]
In the following, means for achieving the above object and its effects are described.
The fuel injection timing control device for a direct injection engine according to claim 1 is a fuel injection timing control device for a direct injection engine that injects fuel into the combustion chamber, and is based on the operating state of the engine. When the injection timing exists in the compression stroke period based on the blowback amount calculation means for calculating the blowback amount of the burned gas from the engine to the intake system and the burnup amount of the burnt gas calculated by the blowback amount calculation means Is provided with a fuel injection timing correction means for correcting the advance angle of the fuel injection timing.
[0009]
If the amount of burned gas blowback from the combustion chamber to the intake system increases, the smoke present in the burned gas also increases the amount of blowback to the intake system, which may contaminate the intake system. Therefore, the fuel injection timing correction means corrects the advance of the fuel injection timing when there is an injection timing in the compression stroke period based on the amount of burned-back gas. By correcting the advance of the fuel injection timing during the compression stroke, the distance between the fuel injection valve and the piston top surface is increased during fuel injection, and the amount of liquid fuel adhering to the piston top surface is reduced. For this reason, the amount of incompletely combusted fuel is reduced, so that the smoke concentration in the burned gas is suppressed. As a result, the amount of smoke entering the intake system on the burnt back burned gas is also reduced. For this reason, smoke pollution of the intake system can be suppressed.
[0010]
According to a fuel injection timing control device for a direct injection type engine according to claim 2, the fuel injection timing correction means according to claim 1 is based on the blowback amount of burned gas calculated by the blowback amount calculation means. Thus, the fuel injection timing is advanced when the injection timing is present in the compression stroke period, and the fuel injection timing is retarded when the injection timing is present during the intake stroke period.
[0011]
The fuel injection timing correction means may correct the fuel injection timing for the fuel injection in the intake stroke period in addition to the advance correction during the compression stroke injection. This increases the distance between the fuel injection valve and the piston top surface during fuel injection in the intake stroke, and reduces the amount of liquid fuel adhering to the piston top surface. As a result, the amount of incompletely combusted fuel is reduced, so that the smoke concentration in the burned gas is suppressed.As a result, the amount of smoke that enters the burned-in burned gas and enters the intake system is reduced, and the smoke in the intake system is reduced. Contamination can be suppressed.
[0012]
Therefore, by performing both the advance angle correction at the time of the compression stroke injection and the delay angle correction at the time of the intake stroke injection, smoke contamination of the intake system can be more effectively suppressed.
A fuel injection timing control device for a direct injection engine according to claim 3 is a fuel injection timing control device for a direct injection engine that injects fuel into the combustion chamber, and is based on the operating state of the engine. When the injection timing is present in the intake stroke period based on the blowback amount calculation means for calculating the return amount of burnt gas from the engine to the intake system and the return amount of burnt gas calculated by the blowback amount calculation means Is provided with a fuel injection timing correction means for correcting the delay of the fuel injection timing.
[0013]
The fuel injection timing correction means corrects the delay of the fuel injection timing when there is an injection timing in the intake stroke period based on the amount of burned-back gas. By correcting the retard of the fuel injection timing during the intake stroke, the distance between the fuel injection valve and the piston top surface is increased during fuel injection, and the amount of liquid fuel adhering to the piston top surface is reduced. As a result, the amount of incompletely combusted fuel is reduced, so that the smoke concentration in the burned gas is suppressed.As a result, the amount of smoke that enters the burned-in burned gas and enters the intake system is reduced, and the smoke in the intake system is reduced. Contamination can be suppressed.
[0014]
The fuel injection timing control device for a direct injection type engine according to claim 4, wherein the fuel injection timing correction means is configured to detect the smoke concentration of burned gas based on the operating state of the engine. And the fuel injection timing is corrected based on the smoke concentration and the amount of blown-back of burned gas calculated by the amount of blow-back calculating means.
[0015]
The amount of smoke blown back to the intake system can be determined from the smoke concentration in the burnt gas and the amount of blowback of the burnt gas. For this reason, the fuel injection timing correcting means corrects the fuel injection timing based on the smoke concentration and the burned back amount of burned gas so that the intake system can be more appropriately dealt with by the injection timing correction for the contamination of the intake system. Thus, smoke pollution of the intake system can be effectively suppressed.
[0016]
6. The fuel injection timing control device for a direct injection type engine according to claim 5, wherein the fuel injection timing correction means is the burned gas calculated by the smoke concentration and the blowback amount calculation means. The amount of smoke blown back to the intake system is determined based on the amount of blown back, and the fuel injection timing is corrected so that the amount of smoke blown back falls within the reference range.
[0017]
In this way, by correcting the fuel injection timing so that the amount of smoke blowback falls within the reference range, it becomes possible to more appropriately cope with contamination of the intake system by correcting the injection timing. Smoke fouling can be suppressed.
[0018]
The fuel injection timing control device for a direct injection type engine according to claim 6, wherein the blowback amount calculation means calculates the blowback amount according to a valve overlap period. It is characterized by.
[0019]
The ease with which burned gas flows into the intake system varies depending on the valve overlap period. For this reason, by using the parameter of the valve overlap period for calculating the blowback amount, the amount of burned gas blown back to the intake system can be calculated more accurately, and the degree of contamination of the intake system can be determined more appropriately.
[0020]
The fuel injection timing control device for a direct injection type engine according to claim 7, wherein the blowback amount calculation means calculates the blowback amount according to an intake pressure. And
[0021]
The ease with which burned gas flows into the intake system varies depending on the degree of intake pressure. For this reason, by using the parameter of the intake pressure for calculating the blowback amount, the amount of burned gas blown back into the intake system can be calculated more accurately, and the degree of contamination of the intake system can be determined more appropriately.
[0022]
In the fuel injection timing control device for a direct injection type engine according to claim 8, the blowback amount calculation means according to any one of claims 1 to 5, wherein the exhaust valve closing timing is set to an exhaust valve closing timing and an intake valve opening timing. The blowback amount is calculated accordingly.
[0023]
The extent of the valve overlap period is also determined by the closing timing of the exhaust valve and the opening timing of the intake valve, and the burned gas to the intake system depends on the closing timing of the exhaust valve and the opening timing of the intake valve. The ease of flow is also different. For this reason, by using the parameters of the exhaust valve closing timing and the intake valve opening timing to calculate the blowback amount, the amount of burned gas blowback to the intake system can be calculated more accurately, and the intake system fouling Can be judged more appropriately.
[0024]
The fuel injection timing control device for a direct injection type engine according to claim 9, wherein the blowback amount calculating means calculates the blowback amount according to the engine speed. Features.
[0025]
The ease with which burned gas flows into the intake system depends on the engine speed. Therefore, by using the engine speed parameter for calculating the blowback amount, the amount of burned gas blown back to the intake system can be calculated more accurately, and the degree of contamination of the intake system can be determined more appropriately.
[0026]
In the fuel injection timing control device for a direct injection type engine according to claim 10, in any one of claims 1 to 5, the blowback amount calculation means calculates the blowback amount according to a valve overlap period and an intake pressure. It is characterized by calculating.
[0027]
In this way, by making the blowback amount calculation means calculate the blowback amount according to the valve overlap period and the intake pressure, it is possible to calculate the blowback amount of burned gas to the intake system more accurately, and the intake system fouling Can be judged more appropriately.
[0028]
In the fuel injection timing control device for a direct injection type engine according to claim 11, in any one of claims 1 to 5, the blowback amount calculation means is in accordance with a valve overlap period, intake pressure and engine speed. The amount of blowback is calculated.
[0029]
Thus, by making the blowback amount calculation means calculate the blowback amount according to the valve overlap period, the intake pressure and the engine speed, the blowback amount of the burned gas to the intake system can be calculated more accurately. The degree of contamination of the intake system can be judged more appropriately.
[0030]
In the fuel injection timing control device for a direct injection type engine according to claim 12, the blowback amount calculation means according to any one of claims 1 to 5, wherein the blowback amount calculation means includes a valve closing timing of the exhaust valve, a valve opening timing of the intake valve, and The blowback amount is calculated according to the intake pressure.
[0031]
In this way, the blowback amount calculation means calculates the blowback amount according to the closing timing of the exhaust valve, the opening timing of the intake valve, and the intake pressure, so that the burned gas blowback to the intake system can be performed more accurately. The amount can be calculated, and the degree of contamination of the intake system can be judged more appropriately.
[0032]
In the fuel injection timing control device for a direct injection type engine according to claim 13, in any one of claims 1 to 5, the blowback amount calculating means includes: an exhaust valve closing timing, an intake valve opening timing, The blowback amount is calculated according to the intake pressure and the engine speed.
[0033]
In this way, the blowback amount calculation means calculates the blowback amount according to the exhaust valve closing timing, the intake valve opening timing, the intake pressure, and the engine speed, so that the intake system to the intake system can be more accurately calculated. The amount of return of the fuel gas can be calculated, and the degree of contamination of the intake system can be judged more appropriately.
[0034]
In the fuel injection timing control device for a direct injection type engine according to claim 14, in any one of claims 6, 8, 10 to 13, the blow-back amount calculating means increases the blow-back amount as the valve overlap period becomes longer. It is characterized by a large calculation.
[0035]
If the valve overlap period becomes longer, the degree to which the burned gas that has flowed into the exhaust system flows again into the intake system side increases. Therefore, the blowback amount calculation means calculates the blowback amount larger as the valve overlap period becomes longer. . Thus, the amount of burned gas blown back into the intake system can be calculated more appropriately, and the degree of contamination of the intake system can be determined more appropriately.
[0036]
The fuel injection timing control device for a direct injection type engine according to claim 15, wherein the blowback amount calculation means calculates the blowback amount larger as the intake pressure becomes lower. It is characterized by.
[0037]
If the intake pressure is low, the burned gas easily flows in against the pressure of the intake system. Therefore, the blowback amount calculating means calculates the blowback amount to be larger as the intake pressure is lower. Thus, the amount of burned gas blown back into the intake system can be calculated more appropriately, and the degree of contamination of the intake system can be determined more appropriately.
[0038]
The fuel injection timing control device for a direct injection type engine according to claim 16, wherein the blowback amount calculation means calculates the blowback amount larger as the engine speed decreases. It is characterized by that.
[0039]
If the engine speed decreases, the time during which the intake valve is opened and the time length of the valve overlap period become longer, and the degree to which the burned gas flows again into the intake system increases. The amount calculation means calculates the amount of blowback larger as the engine speed decreases. Thus, the amount of burned gas blown back into the intake system can be calculated more appropriately, and the degree of contamination of the intake system can be determined more appropriately.
[0040]
The fuel injection timing control device for a direct injection engine according to claim 17 is a fuel injection timing control device for a direct injection engine that injects fuel into a combustion chamber, and is based on the operating state of the engine. A physical quantity calculated by the smoke physical quantity calculating means when there is a fuel injection timing in a compression stroke period and a physical quantity calculating means for calculating a physical quantity representing the smoke quantity in the gas or a physical quantity reflecting the smoke quantity. And a fuel injection timing correcting means for correcting the advance of the fuel injection timing.
[0041]
Smoke in the burnt gas is generated by the adhesion of liquid fuel to the piston top surface. The earlier the piston top surface position in the compression stroke, the farther away from the fuel injection valve. Therefore, the fuel injection timing correction means corrects the advance angle of the fuel injection timing based on the physical quantity representing the smoke amount in the burned gas or the physical quantity reflecting the smoke amount, so that the top surface of the piston is injected at the fuel injection timing. The valve can be separated from the valve, and adhesion of liquid fuel to the piston top surface can be suppressed. As a result, the amount of smoke in the exhaust and smoke pollution of the intake system can be suppressed.
[0042]
The fuel injection timing control device for a direct injection type engine according to claim 18, wherein the fuel injection timing correction means is a compression stroke period based on the physical quantity calculated by the smoke physical quantity calculation means. When the injection timing is present, the fuel injection timing is corrected to advance, and when the injection timing is present during the intake stroke period, the fuel injection timing is corrected to retard.
[0043]
In addition to the advance correction at the time of the compression stroke injection based on the physical quantity, the fuel injection timing correction means may further delay the fuel injection timing based on the physical quantity for the fuel injection during the intake stroke period. good. This increases the distance between the fuel injection valve and the piston top surface during fuel injection in the intake stroke, and reduces the amount of liquid fuel adhering to the piston top surface. Thus, by executing both the advance angle correction during the compression stroke injection and the retard angle correction during the intake stroke injection, it is possible to more effectively suppress the smoke amount in the exhaust and the smoke pollution of the intake system. .
[0044]
The fuel injection timing control device for a direct injection type engine according to claim 19 is the fuel injection timing control apparatus according to claim 17 or 18, wherein the smoke physical quantity calculating means uses the piston top associated with fuel injection as the physical quantity based on the operating state of the engine. The amount of fuel adhering to the surface is calculated.
[0045]
In this way, the amount of fuel adhering to the piston top surface may be calculated as a physical quantity. This provides a physical quantity that can appropriately determine the degree of smoke generation, and corrects the fuel injection timing based on this physical quantity to more appropriately suppress the smoke quantity in the exhaust and smoke pollution of the intake system. it can.
[0046]
The fuel injection timing control device for a direct injection type engine according to claim 20, wherein the smoke physical quantity calculating means calculates the physical quantity according to fuel injection pressure. And
[0047]
Since the fuel injection pressure affects the fuel injection speed, it affects the amount of liquid fuel adhering to the piston top surface. Therefore, by using the fuel injection pressure as a parameter for calculating the physical quantity, a physical quantity that can appropriately determine the degree of smoke generation is obtained, and by correcting the fuel injection timing based on this physical quantity, the exhaust gas is more appropriately exhausted. The amount of smoke inside and smoke contamination of the intake system can be suppressed.
[0048]
The fuel injection timing control device for a direct injection type engine according to claim 21 is characterized in that, in claim 20, the smoke physical quantity calculating means calculates the physical quantity larger as the fuel injection pressure is higher.
[0049]
The higher the fuel injection pressure, the higher the fuel injection speed, the longer the liquid fuel reach, the more easily the liquid fuel adheres to the piston top surface, and the higher the smoke concentration. Therefore, by increasing the physical quantity as the fuel injection pressure increases, a physical quantity that can appropriately determine the degree of smoke generation can be set, and by correcting the fuel injection timing based on this physical quantity, the smoke in the exhaust gas can be more appropriately determined. Smoke pollution of the quantity and intake system can be suppressed.
[0050]
The fuel injection timing control device for a direct injection type engine according to claim 22, wherein the smoke physical quantity calculating means calculates the physical quantity according to the engine speed. And
[0051]
Since the engine speed represents the moving speed of the piston, it affects the amount of liquid fuel adhering to the top surface of the piston. Therefore, by using the engine speed as a parameter for calculating the physical quantity, a physical quantity that can appropriately determine the degree of smoke generation is obtained, and by correcting the fuel injection timing based on this physical quantity, the exhaust gas is more appropriately exhausted. The amount of smoke inside and smoke contamination of the intake system can be suppressed.
[0052]
In the fuel injection timing control device for a direct injection type engine according to claim 23, in claim 22, the smoke physical quantity calculating means increases the engine rotational speed when the injection timing exists during the compression stroke period. The physical quantity is calculated to be large.
[0053]
At the time of compression stroke injection, the piston top surface is approaching the fuel injection valve, so that the higher the engine speed, the quicker the approach and the liquid fuel tends to adhere. For this reason, during the compression stroke injection, the smoke physical quantity calculation means calculates the physical quantity to be larger as the engine speed is higher, thereby obtaining a physical quantity that can appropriately determine the degree of occurrence of smoke. Therefore, by correcting the fuel injection timing based on this physical quantity, it is possible to more appropriately suppress the smoke quantity in the exhaust and the smoke pollution of the intake system.
[0054]
In a fuel injection timing control device for a direct injection type engine according to claim 24, in claim 22, the smoke physical quantity calculating means is configured such that when the injection timing is present in the intake stroke period, the lower the engine speed is, The physical quantity is largely calculated.
[0055]
At the time of intake stroke injection, the piston top surface is moving away from the fuel injection valve. Therefore, the lower the engine speed, the slower the distance from the piston, and the liquid fuel tends to adhere. Therefore, during the intake stroke injection, the smoke physical quantity calculation means calculates the physical quantity to be larger as the engine speed is lower, thereby obtaining a physical quantity that can appropriately determine the degree of smoke generation. Therefore, by correcting the fuel injection timing based on this physical quantity, it is possible to more appropriately suppress the smoke quantity in the exhaust and the smoke pollution of the intake system.
[0056]
A fuel injection timing control device for a direct injection type engine according to claim 25, wherein the smoke physical quantity calculating means calculates the physical quantity according to the engine temperature. To do.
[0057]
Since the engine temperature affects the vaporization of the liquid fuel, it affects the amount of liquid fuel adhering to the piston top surface. Therefore, by using the engine temperature as a parameter for calculating the physical quantity, a physical quantity that can appropriately determine the degree of smoke generation is obtained, and by correcting the fuel injection timing based on this physical quantity, the exhaust gas is more appropriately exhausted. The amount of smoke and the smoke pollution of the intake system can be suppressed.
[0058]
In a fuel injection timing control device for a direct injection type engine according to claim 26, in claim 25, the smoke physical quantity calculating means calculates the physical quantity larger as the engine temperature is lower.
[0059]
The lower the engine temperature, the easier the liquid fuel reaches the top surface of the piston, and the liquid fuel at the top surface of the piston is less likely to vaporize, so the liquid fuel tends to accumulate on the top surface of the piston. For this reason, the smoke physical quantity calculating means calculates the physical quantity to be larger as the engine temperature is lower, thereby obtaining a physical quantity that can appropriately determine the degree of occurrence of smoke. Therefore, by correcting the fuel injection timing based on this physical quantity, it is possible to more appropriately suppress the smoke quantity in the exhaust and the smoke pollution of the intake system.
[0074]
Claim 27 The fuel injection timing control device for a cylinder injection type engine described in 1 includes a variable valve system that adjusts valve timing in accordance with the operating state of the engine, and fuel injection for a cylinder injection type engine that injects fuel into the combustion chamber. A timing control device, a valve overlap detecting means for detecting a valve overlap period, a smoke blowback state determining means for determining whether or not the engine is in an operating state in which the amount of smoke blowback to the intake system increases, and a compression stroke When it is determined by the smoke blowback state determination means that the amount of smoke blowback to the intake system is increased when the fuel injection timing exists in the period, the valve overlap detection means Fuel injection timing correction means for correcting the advance of the fuel injection timing based on the detected valve overlap period. The features.
[0075]
In the case where the valve timing is adjusted according to the operating state of the engine by providing a variable valve system, even if the valve overlap period is long, there is not always a possibility of smoke contamination of the intake system. When the amount of blown back is large, the influence of the valve overlap period occurs. Therefore, the fuel injection timing correction means is based on the valve overlap period when the smoke blowback state determination means determines that the engine is in an engine operating state in which the amount of smoke blowback to the intake system increases during the compression stroke injection. The fuel injection timing is advanced. As a result, it is possible to accurately suppress intake system contamination, and advance angle correction for suppressing intake system contamination under limited conditions makes it easy to maintain high engine performance.
[0076]
Claim 28 In the fuel injection timing control device for a direct injection type engine according to claim 1, 27 When the fuel injection timing correction means determines that the smoke blowback state determination means is in an engine operating state in which the amount of smoke blowback to the intake system increases, the valve overlap detection means Based on the detected valve overlap period, the fuel injection timing is advanced when the injection timing is present during the compression stroke period, and the fuel injection timing is retarded when the injection timing is present during the intake stroke period. It is characterized by.
[0077]
When the fuel injection timing correction means determines that the engine is in an engine operating state in which the amount of smoke blown back into the intake system increases during the intake stroke injection in addition to the advance angle correction during the compression stroke injection. In addition, the fuel injection timing is retarded based on the valve overlap period. This makes it possible to accurately suppress intake system contamination even during intake stroke injection, and to perform retard correction to suppress intake system contamination under limited conditions, maintaining engine performance at a high level. It becomes easy.
[0078]
Claim 29 The fuel injection timing control device for a cylinder injection type engine described in 1 includes a variable valve system that adjusts valve timing in accordance with the operating state of the engine, and fuel injection for a cylinder injection type engine that injects fuel into the combustion chamber. A timing control device, a valve overlap detecting means for detecting a valve overlap period, a smoke blowback state determining means for determining whether or not an engine operation state in which the amount of smoke blowback to the intake system increases, and an intake stroke; When it is determined by the smoke blowback state determination means that the amount of smoke blowback to the intake system is increased when the fuel injection timing exists in the period, the valve overlap detection means Fuel injection timing correction means for delaying the fuel injection timing based on the detected valve overlap period. The features.
[0079]
In this way, the fuel injection timing correction means is in the valve overlap period when the smoke blow-back state determination means determines that the amount of smoke blow-back to the intake system is large during the intake stroke injection. Based on this, the fuel injection timing may be retarded. This makes it possible to accurately control intake system contamination during intake stroke injection, and to perform retard correction to control intake system contamination under limited conditions, making it easy to maintain high engine performance. Become.
[0080]
Claim 30 In the fuel injection timing control device for a direct injection type engine according to claim 1, 27 ~ 29 In any of the above, the fuel injection timing correction means corrects the fuel injection timing larger as the valve overlap period becomes longer.
[0081]
In an engine operating state where the amount of smoke blown back into the intake system increases, the longer the valve overlap period, the greater the amount of burnt gas blown back into the intake system. Will also increase. Therefore, the fuel injection timing correction means corrects the fuel injection timing larger as the valve overlap period becomes longer, so that the intake system can be prevented from fouling accurately.
[0082]
Claim 31 In the fuel injection timing control device for a direct injection type engine according to claim 1, 27 ~ 30 In any of the above, the smoke blow-back state determination means has a large amount of smoke blow-back to the intake system when one or more of the conditions of low rotation, low intake pressure and low engine temperature are satisfied. It is determined that the engine is operating.
[0083]
If the engine speed decreases, the time during which the intake valve is opened and the time length of the valve overlap period will increase, and the amount of burnt gas will flow again into the intake system, increasing the amount of blowback. Will increase. If the intake pressure is lowered, the burned gas easily flows in against the pressure of the intake system, so that the amount of blowback increases. When the engine temperature is lowered, the vaporization of the injected liquid fuel and the liquid fuel on the piston top surface is delayed, the amount of liquid fuel adhering to the piston top surface is increased, and the smoke concentration is increased. These low rotation, low intake pressure and low engine temperature Inside When one or more conditions are satisfied, the smoke blowback amount is a bad condition. Under such conditions, the fuel injection timing correction means corrects the fuel injection timing based on the valve overlap period, so that it is possible to accurately suppress intake system contamination and to suppress intake system contamination under limited conditions. Therefore, it is easy to maintain the engine performance at a high level.
[0084]
Claim 32 In the fuel injection timing control device for a direct injection type engine according to claim 1, 31 The fuel injection timing correction means determines that the smoke blow-back state determination means determines that the engine is in an engine operating state in which the amount of smoke blow-back to the intake system increases due to the low engine temperature condition being satisfied. When the correction is made, the correction for the fuel injection timing is gradually reduced in accordance with the increase in the engine temperature.
[0085]
When it is determined that the engine is in an operating state in which the amount of smoke blown back into the intake system increases when the low engine temperature condition is satisfied, and the fuel injection timing is corrected based on the valve overlap period, the fuel injection timing The correction means may gradually decrease the correction for the fuel injection timing in accordance with the increase in engine temperature. This can prevent a shock that occurs in the engine when the fuel injection timing is returned to the normal fuel injection timing.
[0086]
Claim 33 In the fuel injection timing control device for a direct injection type engine according to claim 1, 31 Or 32 The fuel injection timing correction means adds a process of increasing the correction according to the increase in the valve overlap period when the valve overlap period increases as the engine temperature increases. .
[0087]
Depending on the engine control, the valve overlap period may be increased as the engine temperature increases. When the valve overlap period increases due to such an increase in engine temperature, the burned gas blows back in large quantities, so that the intake system fouling can be suppressed as the valve overlap period increases. Therefore, a process for increasing the injection timing correction may be added. This makes it possible to accurately suppress the intake system from being contaminated.
[0088]
Claim 34 The fuel injection timing control device for a direct injection type engine according to claim 1 is obtained by executing in advance processing of the blowback amount calculation means and the fuel injection timing correction means according to any one of claims 1 to 16. The fuel injection timing of the direct injection type engine is controlled using a correction value of the fuel injection timing using the engine operating state as a parameter or a map of the corrected fuel injection timing.
[0089]
When the fuel injection timing of the in-cylinder injection engine is controlled by using the map obtained by executing the processing of the blowback amount calculation means and the fuel injection timing correction means in advance as described above, And the load with respect to a fuel-injection timing control apparatus can be suppressed with the effect of any one of Claims 1-16. For this reason, an inexpensive arithmetic unit can be used, and the processing can be speeded up.
[0090]
Claim 35 The fuel injection timing control device for a cylinder injection type engine according to claim 18 is obtained by executing in advance the processing of the smoke physical quantity calculating means and the fuel injection timing correcting means in any one of claims 17 to 26. The fuel injection timing of the direct injection type engine is controlled using a correction value of the fuel injection timing using the engine operating state as a parameter or a map of the corrected fuel injection timing.
[0091]
When the fuel injection timing of the in-cylinder injection engine is controlled by using the map obtained by executing the processing of the smoke physical quantity calculation means and the fuel injection timing correction means in advance as described above, And the load with respect to a fuel-injection timing control apparatus can be suppressed with the effect in any one of Claims 17-26. For this reason, an inexpensive arithmetic unit can be used, and the processing can be speeded up.
[0094]
Claim 36 A fuel injection timing control device for a direct injection type engine according to claim 1, 27 ~ 33 The correction value of the fuel injection timing with the operating state of the engine as a parameter obtained by executing the processing of the valve overlap detection means, the smoke blow-back state determination means and the fuel injection timing correction means in advance Alternatively, the fuel injection timing of the direct injection type engine is controlled using a map of the corrected fuel injection timing.
[0095]
Thus, by using the map obtained by executing the processing of the valve overlap detection means, the smoke blow-back state determination means and the fuel injection timing correction means in advance, the fuel injection of the in-cylinder injection type engine is performed. When controlling time, claims 27 ~ 33 Any one of the following effects is produced. With this, the load on the fuel injection timing control device can be suppressed. For this reason, an inexpensive arithmetic unit can be used, and the processing can be speeded up.
[0096]
DETAILED DESCRIPTION OF THE INVENTION
[Embodiment 1]
FIG. 1 shows a gasoline engine (hereinafter abbreviated as “engine”) 2 corresponding to an in-cylinder injection engine mounted on a vehicle, and an electronic control unit (hereinafter referred to as “ECU”) corresponding to a fuel injection control device. 4 shows a schematic system diagram. Although the engine 2 is a four-cylinder internal combustion engine, only one cylinder is shown in a longitudinal sectional view in FIG. Further, each cylinder is a four-valve engine provided with two intake valves 2a and two exhaust valves 2b. The number of cylinders may be 6 cylinders or 8 cylinders, and may be a 2-valve engine or a 5-valve engine.
[0097]
The output of the engine 2 is finally transmitted as traveling driving force to the wheels via the transmission. The engine 2 is provided with a fuel injection valve 12 for directly injecting fuel into the combustion chamber 10 and a spark plug 14 for igniting the injected fuel. The intake port 16 connected to the combustion chamber 10 is opened and closed by driving the intake valve 2a. A surge tank 22 is provided in the middle of the intake passage 20 connected to the intake port 16, and a throttle valve 26 whose opening degree is adjusted by a motor 24 is provided upstream of the surge tank 22. The intake air amount is adjusted by the opening of the throttle valve 26 (throttle opening TA). The throttle opening degree TA is detected by a throttle opening degree sensor 28, and the intake air amount Ga of the engine 2 is detected by an intake air amount sensor 30 provided in the intake passage 20 and read into the ECU 4.
[0098]
The exhaust port 32 connected to the combustion chamber 10 is opened and closed by driving the exhaust valve 2b. An exhaust purification catalyst 38 such as a three-way catalyst or a NOx occlusion reduction catalyst is disposed in the middle of the exhaust passage 36 connected to the exhaust port 32.
[0099]
The fuel injection valve 12 is connected to a delivery pipe that constitutes a high-pressure fuel path, and is supplied with high-pressure fuel from a high-pressure fuel pump via the delivery pipe. In the delivery pipe, the ECU 4 causes the high pressure fuel pump from the high pressure fuel pump to the delivery pipe side so that the fuel pressure Pf (corresponding to the fuel injection pressure) detected by the fuel pressure sensor 40 becomes the target fuel pressure corresponding to the engine operating state. This is done by adjusting the discharge amount.
[0100]
Here, the intake valve 2a and the exhaust valve 2b are configured as intake and exhaust valves of a variable valve system. That is, the intake cam 42 opens and closes the intake valve 2 a via the intake variable valve mechanism 43. The exhaust cam 44 drives the exhaust valve 2b to open and close via an exhaust variable valve mechanism 45. As each of the variable valve mechanisms 43 and 45, for example, a variable valve mechanism described in Japanese Patent Laid-Open No. 2001-263015 can be used, but a variable valve mechanism having a configuration other than this may be used. Each of the variable valve mechanisms 43 and 45 can change the valve timing of the intake valve 2a and the exhaust valve 2b according to a command from the ECU 4. Thus, it is possible to adjust the length of the valve overlap period or the crank angle phase position, which is the overlap of the valve opening timings of the intake valve 2a and the exhaust valve 2b. Each of the variable valve mechanisms 43 and 45 has a configuration in which the valve timing is adjusted by the stroke amount of the control shaft, and each stroke sensor 43a and 45a detects this stroke amount and outputs it to the ECU 4.
[0101]
The ECU 4 is an engine control circuit mainly configured by a digital computer having a CPU, ROM, RAM, and the like. The throttle opening sensor 28, the intake air amount sensor 30, the fuel pressure sensor 40, and the stroke sensors 43a and 45a described above. In addition, signals are input from various sensors. That is, an accelerator opening sensor 48 that detects the amount of depression of the accelerator pedal 46 (accelerator opening ACCP), an engine speed sensor 50 that detects the engine speed NE from the crankshaft rotation, and a reference crank angle are determined from the intake camshaft rotation. A signal is input from the reference crank angle sensor 52. Further, signals are input from a coolant temperature sensor 54 that detects the engine coolant temperature THW, an air-fuel ratio sensor 56 that detects the air-fuel ratio of the air-fuel mixture from exhaust components in the exhaust passage, and a travel distance meter 58.
[0102]
The ECU 4 appropriately controls the fuel injection timing of the engine 2, the fuel injection amount, the throttle opening, the valve timings of the intake and exhaust valves 2a and 2b, and the like based on the detection contents from the above-described sensors. As a result, the combustion mode is switched between stratified combustion by compression stroke injection and homogeneous combustion by intake stroke injection. In the first embodiment, for example, the intake stroke injection is executed at the start, and when the engine speed NE is stabilized after the start, the engine is switched to the compression stroke injection, and thereafter, based on the map of the engine speed NE and the load factor eklq. The combustion form is determined. Here, the load factor eklq indicates the ratio of the current load to the maximum engine load based on the accelerator opening ACCP and the engine speed NE. For example, the map includes the accelerator opening ACCP and the engine speed NE as parameters. It is a value obtained from
[0103]
Further, during start-up and cold, the valve overlap period is set to "0" (the valve opening timing of the intake / exhaust valves 2a, 2b is not overlapped) or "0" by the valve timing control of the intake / exhaust valves 2a, 2b. Close to a small crank width. In engine operation after warm-up, the valve overlap period is determined based on a map of engine speed NE and load factor eklq.
[0104]
Next, the fuel injection timing control process among the controls executed by the ECU 4 will be described. A flowchart of this process is shown in FIG. This process is a process that is repeatedly executed at a crank angle cycle corresponding to the number of cylinders, in this case four cylinders, so that the cycle is 180 ° CA (CA: crank angle). The steps in the flowchart corresponding to the individual processing contents are represented by “S˜”.
[0105]
When this processing is started, first, the intake valve 2a and the exhaust valve 2b calculated from the intake air amount Ga, the engine speed NE, the load factor eklq, and the detected values of the stroke sensors 43a and 45a that are currently detected. The timing is read into a work area of a RAM provided in the ECU 4 (S102). Then, based on the load factor eklq and the engine speed NE, the basic fuel injection timing θainj is calculated from a basic fuel injection timing map prepared in advance by experiments (S104).
[0106]
Next, the intake pressure Pi at the intake port 16 is calculated from the intake air amount Ga and the engine speed NE (S106). The calculation of the intake pressure Pi may be obtained from an arithmetic expression, or may be obtained from a map prepared in advance by experiments.
[0107]
Next, the intake port blow-back smoke amount Smret (mg) is calculated (S108). The intake port blowback smoke amount Smret represents the amount of smoke blown back from the combustion chamber 10 side to the intake system. The intake port blow-back smoke amount Smret is calculated as follows.
[0108]
First, the intake port blown back burned gas amount Exret (mg) is expressed as a valve overlap period Lovr represented by a crank angle width calculated from the opening timing of the intake valve 2a and the closing timing of the exhaust valve 2b, and the intake pressure. Based on Pi and the engine speed NE, it is obtained from a map prepared in advance by experiments.
[0109]
The map for obtaining the intake port blown-back burned gas amount Exret is set so that the intake port blow-back burned gas amount Exret increases as the valve overlap period Lovr becomes longer. If the valve overlap period Lovr becomes longer, the burned gas that has flowed into the exhaust system (the exhaust port 32 and the exhaust passage 36) flows again into the intake system (the intake port 16 and the intake passage 20) through the combustion chamber 10. It is because the degree to do increases.
[0110]
The intake pressure Pi is set such that the lower the intake pressure Pi, the larger the amount of burned exhaust gas Exret. This is because if the intake pressure Pi is lowered, the burned gas is easily sucked into the intake system from the combustion chamber 10 side.
[0111]
The engine speed NE is set such that the lower the engine speed NE, the larger the amount of burnt gas Exret returned to the intake port. This is because if the engine speed NE is low, the time during which the intake valve 2a is opened and the valve overlap period Lovr are lengthened, and the degree to which the burned gas flows again into the intake system increases. .
[0112]
Next, the smoke concentration Smdty (% by weight) generated according to the operating state of the engine 2 is calculated. Here, the smoke concentration Smdty is calculated by a map prepared in advance by experiments based on the load factor eklq, the engine speed NE, and the fuel injection mode of intake stroke injection or compression stroke injection. It should be noted that the amount of liquid fuel adhering to the piston top surface 6a as calculated in the embodiments described later may also be included in the parameters.
[0113]
Then, the intake port blowback smoke amount Smret is obtained by the product of the intake port blowback burned gas amount Exret and the smoke concentration Smdty.
Next, it is determined whether or not the intake port blowback smoke amount Smret is larger than the intake port blowback smoke allowable amount Aret (S110). If Smret ≦ Aret (“NO” in S110), the basic fuel injection timing θainj obtained in step S104 is set as the fuel injection timing θinj (S112). Then, the actual fuel injection timing is set based on the fuel injection timing θinj (S118), and this process is temporarily terminated. The fuel injection timing θinj is set as an advance value with respect to the reference crank angle. For this reason, when the fuel injection timing θinj is increased, the actual fuel injection timing is also advanced correspondingly.
[0114]
On the other hand, if Smret> Aret (“YES” in S110), a correction value θsm corresponding to the values of the fuel injection mode and the intake port blowback smoke amount Smret is calculated in order to suppress the intake port blowback smoke amount (Smret> Aret). S114). The correction value θsm is expressed as an advance correction value, and θsm> 0 when correcting to the advance side, and θsm <0 when correcting to the retard side. Therefore, in both the case of correcting to the advance side and the case of correcting to the retard side, if the absolute value of the correction value θsm is increased, the correction is greatly made.
[0115]
FIG. 3 shows the relationship between the fuel injection timing and the smoke concentration Smdty. That is, when there is a fuel injection timing region in which the smoke concentration Smdty is small and this fuel injection timing region deviates to the advance side in the intake stroke, or deviates to the retard side in the compression stroke, the smoke concentration Smdty suddenly increases. To rise. This is because in the fuel injection in the intake stroke, the piston top surface 6a moves in a direction away from the fuel injection valve 12. Therefore, when the fuel injection timing is advanced, the piston top surface 6a is in a position close to the fuel injection valve 12. Is injected. This is because liquid fuel tends to adhere to the piston top surface 6a, and smoke is likely to be generated due to incomplete combustion. In addition, in the fuel injection in the compression stroke, the piston top surface 6a moves in a direction approaching the fuel injection valve 12. Therefore, if the fuel injection timing is retarded, the piston top surface 6a is fueled at a position close to the fuel injection valve 12. Is injected. This is because liquid fuel tends to adhere to the piston top surface 6a, and smoke is likely to be generated due to incomplete combustion.
[0116]
When the fuel injection mode is intake stroke injection, in FIG. 3, if the smoke concentration Smdty = Sa where Smret> Aret, the current fuel injection timing θsa corresponding to the smoke concentration Sa is Smret = Aret. Is ahead of the fuel injection timing θax by Δθax. Therefore, at the time of intake stroke injection, in order to reduce the intake port blow-back smoke amount Smret, the correction value θsm has a value of “−Δθax” or a value smaller than “−Δθax” (a value larger as an absolute value). Will be set.
[0117]
When the fuel injection mode is compression stroke injection, if the smoke concentration Smdty = Sb where Smret> Aret in FIG. 3, the current fuel injection timing θsb corresponding to this smoke concentration Sb is Smret = Aret. The fuel injection timing θbx is delayed by Δθbx. Therefore, at the time of compression stroke injection, in order to reduce the intake port blow-back smoke amount Smret, the correction value θsm is set to a value of “Δθbx” or a value larger than “Δθbx”.
[0118]
When the correction value θsm is set in this way, the fuel injection timing θinj is set according to the following equation 1 (S116).
[0119]
[Expression 1]
θinj ← θainj + θsm ... [Formula 1]
Since θsm ≦ −Δθax during the intake stroke injection according to the above equation 1, the fuel injection timing θinj is smaller than the basic fuel injection timing θainj. For this reason, the actual fuel injection timing set based on the fuel injection timing θinj in step S118 is delayed from the basic fuel injection timing θainj, and Smdty ≦ “Aret / Exret”. As a result, the actual intake port blow-back smoke amount is suppressed to be equal to or less than the intake port blow-back smoke allowable amount Aret.
[0120]
Further, since θsm ≧ Δθbx during the compression stroke injection, the fuel injection timing θinj is larger than the basic fuel injection timing θainj. For this reason, the actual fuel injection timing set based on the fuel injection timing θinj in step S118 is advanced from the basic fuel injection timing θainj to satisfy Smdty ≦ “Aret / Exret”. As a result, the actual intake port blow-back smoke amount is suppressed to be equal to or less than the intake port blow-back smoke allowable amount Aret.
[0121]
In the above-described configuration, the fuel injection timing control process (FIG. 2) corresponds to the process as the blowback amount calculating means and the fuel injection timing correcting means.
According to the first embodiment described above, the following effects can be obtained.
[0122]
(I). If the amount of burnt gas blown back from the combustion chamber 10 to the intake system increases, the amount of smoke present in the burned gas also increases to the intake system, which may cause the intake system to become dirty. Therefore, in the fuel injection timing control process (FIG. 2), the intake port blowback smoke amount Smret is calculated based on the intake port blowback burned gas amount Exret. Actually, the intake port blowback smoke amount Smret is calculated from the product of the intake port blowback burned gas amount Exret and the smoke concentration Smdty.
[0123]
Then, when the injection timing exists in the compression stroke period, the fuel injection timing is advanced by the intake port blow back smoke amount Smret. By correcting the advance of the fuel injection timing during the compression stroke, the distance between the fuel injection valve 12 and the piston top surface 6a is increased during fuel injection, and the amount of liquid fuel adhering to the piston top surface 6a is reduced. For this reason, the smoke concentration Smdty in the burnt gas is suppressed, and as a result, the intake port blowback smoke amount Smret entering the intake system on the burnt burned gas is also reduced. For this reason, smoke pollution of the intake system can be effectively suppressed.
[0124]
Further, in the fuel injection timing control process (FIG. 2), in addition to the advance angle correction at the time of the compression stroke injection, the fuel injection timing is further corrected by the intake port blowback smoke amount Smret for the fuel injection in the intake stroke period. is doing. This increases the distance between the fuel injection valve 12 and the piston top surface 6a even during fuel injection in the intake stroke, and reduces the amount of liquid fuel adhering to the piston top surface 6a. Therefore, the smoke concentration Smdty in the burned gas is suppressed, and as a result, the intake port blowback smoke amount Smret entering the intake system riding on the burned burned gas is also reduced, and smoke contamination of the intake system is effectively suppressed. it can.
[0125]
Thus, by performing both the advance correction at the time of the compression stroke injection and the delay angle correction at the time of the intake stroke injection, smoke contamination of the intake system can be more effectively suppressed.
(B). In particular, since the fuel injection timing is corrected so that the intake port blow-back smoke amount Smret is equal to or less than the intake port blow-back smoke allowable amount Aret, it becomes possible to appropriately cope with intake system contamination by injection timing correction. Smoke pollution of the intake system can be effectively suppressed.
[0126]
(C). The fuel injection timing is corrected when the valve overlap period obtained from the closing timing of the exhaust valve and the opening timing of the intake valve is longer, the intake pressure Pi is lower, the engine speed NE is lower, and the intake port is blown back. The amount of fuel gas Exret is set large. In this way, the burned-back burned gas amount Exret is calculated according to the valve overlap period, the intake pressure Pi, and the engine speed NE. As a result, the intake port blown back burned gas amount Exret and the intake port blowback smoke amount Smret can be calculated more accurately, and the degree of contamination of the intake system can be more appropriately determined.
[0127]
[Embodiment 2]
In the present embodiment, a smoke amount Smptn (corresponding to a physical amount representing the smoke amount) in the burned gas is calculated, and a process for correcting the fuel injection timing is performed based on the smoke amount Smptn (mg). In the present embodiment, the fuel injection timing control process shown in FIG. 4 is executed instead of the fuel injection timing control process (FIG. 2) of the first embodiment. The other configuration is the same as that of the first embodiment.
[0128]
The fuel injection timing control process (FIG. 4) will be described. This process is repeatedly executed at the same crank angle cycle as the fuel injection timing control process (FIG. 2). When this process is started, first, the currently detected engine speed NE, fuel pressure Pf, engine cooling water temperature THW, load factor eklq, fuel injection time Tinj, and travel distance Ld are read (S202). Here, the fuel injection time Tinj is a value obtained from the load factor eklq, the engine speed NE, and the fuel pressure Pf in the fuel injection amount calculation process separately executed by the ECU 4.
[0129]
Next, as in step S104, the basic fuel injection timing θainj is calculated from the basic fuel injection timing map based on the load factor eklq and the engine speed NE (S204).
[0130]
Next, a piston adhering fuel amount Fptn (mg) is calculated (S206). This piston adhering fuel amount Fptn is estimated fuel that has adhered to the piston top surface 6a in liquid form by the time of ignition by the fuel injected from the fuel injection valve 12 at the basic fuel injection timing θainj obtained in step S204. Represents quantity. The piston adhering fuel amount Fptn is calculated as follows.
[0131]
The amount of fuel adhering to the piston Fptn is determined by the following formula 2 based on the amount of liquid fuel reaching the piston top surface 6a until the ignition timing and the amount of fuel vaporization Fout from the piston top surface 6a.
[0132]
[Expression 2]
Fptn ← Fin−Fout [Formula 2]
As indicated by a solid circle in FIG. 5, the distance that the liquid fuel reaches becomes longer according to the fuel injection speed Vs from the fuel injection valve 12. For this reason, at the time of both the intake stroke injection and the compression stroke injection, as the fuel pressure Pf increases, the difference from the pressure in the combustion chamber 10 increases, and the fuel injection speed Vs increases, leading to the piston top surface 6a (dashed line). The liquid fuel arrival amount Fin increases.
[0133]
Since the liquid fuel is vaporized in the middle of the flight, as indicated by a solid circle in FIG. 6, the liquid fuel arrival amount Fin increases as the engine temperature, here, the engine cooling water temperature THW increases, both during the intake stroke injection and the compression stroke injection. Get smaller.
[0134]
In both the intake stroke injection and the compression stroke injection, as the fuel injection time Tinj becomes longer, the fuel injection amount increases and the liquid fuel arrival amount Fin increases.
During the intake stroke injection, the piston top surface 6a moves away from the fuel injection valve 12. Therefore, as indicated by the solid line on the left side of FIG. 7, the liquid fuel arrival amount Fin decreases as the engine speed NE increases. . During the compression stroke injection, the piston top surface 6a moves in a direction approaching the fuel injection valve 12. Therefore, as shown by the solid line on the right side of FIG. 7, the higher the engine speed NE, the larger the liquid fuel arrival amount Fin. .
[0135]
Further, as can be seen from FIGS. 5 to 7, during the intake stroke injection shown on the left side of each drawing, the piston top surface 6 a moves away from the injection port of the fuel injection valve 12 as the angle is retarded, and the liquid fuel arrival amount Fin is small. Become. At the time of the compression stroke injection shown on the right side of each figure, the piston top surface 6a moves away from the injection port of the fuel injection valve 12 and the liquid fuel arrival amount Fin decreases as the advance angle increases.
[0136]
Based on these facts, as shown in FIG. 8, the basic arrived at the basic using the basic fuel injection timing θainj and the fuel pressure Pf (or the differential pressure between the fuel pressure Pf and the combustion chamber pressure) as parameters, as shown in FIG. A map for obtaining the amount F0 is created for each fuel injection mode. When the differential pressure between the fuel pressure Pf and the combustion chamber pressure is used, the combustion chamber pressure is estimated from the crank angle, and the differential pressure from the fuel pressure Pf is calculated. In addition, the broken line in the map of FIG. 8 shows the outline of the value change of the basic reach F0 in contour lines. The same applies to other maps.
[0137]
Further, as shown in FIG. 9, a map for obtaining the temperature correction coefficient kthw using the basic fuel injection timing θainj and the engine coolant temperature THW as parameters is created for each fuel injection mode. Further, as shown in FIG. 10, a map for obtaining the rotational speed correction coefficient knee using the basic fuel injection timing θainj and the engine rotational speed NE as parameters is created for each fuel injection mode. Further, as shown in FIG. 11, a map for obtaining the injection time correction coefficient kinj using the fuel injection time Tinj as a parameter is created in common for both fuel injection modes.
[0138]
Then, based on the data obtained in steps S202 and S204, the corresponding numerical value is calculated from each map, and the liquid fuel arrival amount Fin is calculated as in the following equation 3.
[0139]
[Equation 3]
Fin ← F0 × kthw × kne × kinj [Formula 3]
The fuel vaporization amount Fout from the piston top surface 6a is determined by the engine temperature and time from fuel injection timing to ignition. Therefore, here, a map for obtaining the fuel vaporization amount Fout based on the engine coolant temperature THW, the basic fuel injection timing θainj, the engine speed NE, and the ignition timing is created in advance by experiments or model calculations. For example, assuming that the ignition timing is constant, it is as shown in FIG. Then, the fuel vaporization amount Fout is obtained from this map.
[0140]
As a result, since the liquid fuel arrival amount Fin and the fuel vaporization amount Fout are obtained, the piston adhering fuel amount Fptn can be estimated by the calculation of the above equation 2.
[0141]
When the piston attached fuel amount Fptn due to fuel injection at the basic fuel injection timing θainj is estimated in step S206 in this way, the smoke amount Smptn is then estimated based on the value of the piston attached fuel amount Fptn (S208). The estimation formula fsm () is determined for each fuel injection mode, but since the magnitude of the smoke amount Smptn corresponds to the magnitude of the piston attached fuel amount Fptn, the value of the piston attached fuel amount Fptn is expressed as follows. The smoke amount Smptn may be set as it is. That is, the piston-attached fuel amount Fptn may be used as a physical quantity that reflects the smoke amount.
[0142]
Next, it is determined whether or not the smoke amount Smptn exceeds the smoke allowable amount smax (S210). If Smptn ≦ smax (“NO” in S210), the basic fuel injection timing θainj obtained in step S204 is set as the fuel injection timing θinj (S212).
[0143]
Then, the actual fuel injection timing is set based on the fuel injection timing θinj (S218), and this process is temporarily terminated.
On the other hand, if Smptn> smax (“YES” in S210), a correction value θptn corresponding to the value of the fuel injection mode and the smoke amount Smptn is calculated (S214). The correction value θptn is expressed as an advance correction value.
[0144]
FIG. 13 shows the relationship between the fuel injection timing θinj and the smoke amount Smptn with a solid line. That is, when there is a fuel injection timing region where the smoke amount Smptn is small and this fuel injection timing region deviates to the advance side in the intake stroke, or deviates to the retard side in the compression stroke, the smoke amount Smptn suddenly increases. To rise. This is because the piston top surface 6a moves away from the fuel injection valve 12 during the intake stroke injection, so that fuel is injected at a position where the piston top surface 6a is close to the fuel injection valve 12 when the fuel injection timing is advanced. This is because the liquid fuel easily adheres to the piston top surface 6a. Further, at the time of compression stroke injection, the piston top surface 6a moves in a direction approaching the fuel injection valve 12. Therefore, when the fuel injection timing is retarded, fuel is injected at a position where the piston top surface 6a is close to the fuel injection valve 12. This is because the liquid fuel easily adheres to the piston top surface 6a.
[0145]
In the intake stroke injection, if the smoke amount Smptn = Sa1 with Smptn> smax in FIG. 13, the current fuel injection timing θsa1 corresponding to the smoke amount Sa1 is from the fuel injection timing θax1 with Smptn = smax. Is also on the advance side of Δθax1. Therefore, when the fuel injection mode is the intake stroke injection, the correction value θptn has a value smaller than “−Δθax1” or a value smaller than “−Δθax1” in order to reduce the smoke amount Smptn (the absolute amount is larger). Value) will be set.
[0146]
At the time of the compression stroke injection, if the smoke amount Smptn = Sb1 where Smptn> smax in FIG. Is also delayed by Δθbx1 minutes. Therefore, when the fuel injection mode is compression stroke injection, the correction value θptn is set to a value of “Δθbx1” or a value larger than “Δθbx1” in order to reduce the smoke amount Smptn.
[0147]
When the correction value θptn is set in this way, the correction value θld corresponding to the travel distance Ld is then calculated (S215). The correction value θld is expressed as an advance correction value.
[0148]
The smoke amount Smptn indicated by a solid line in FIG. 13 indicates the relationship between the fuel injection timing and the smoke amount Smptn when the engine 2 is new. When the engine 2 is operated, the surface state of the piston top surface 6a is smeared with smoke, and it becomes easier to hold the liquid fuel than in the case of a new one. Therefore, the adhering liquid fuel is released by vaporization. It becomes difficult. For this reason, even in the same engine operating state, the amount of fuel adhering to the piston Fptn increases, and the smoke amount Smptn increases as shown by the one-dot chain line.
[0149]
Therefore, at the time of intake stroke injection, in order to keep the smoke amount Sa1 below the smoke allowable amount smax, it is necessary to further delay by Δθax2. During the compression stroke injection, in order to keep the smoke amount Sb1 below the smoke allowable amount smax, it is necessary to further advance the angle by Δθbx2. Accordingly, a map for calculating the correction value θld based on the travel distance Ld is obtained in advance through experiments and model calculations as shown in FIG. 14, and the correction value θld is calculated from the travel distance Ld using this map.
[0150]
When the two correction values θptn and θld are thus set, the fuel injection timing θinj is set according to the following equation 4 (S216).
[0151]
[Expression 4]
θinj ← θainj + θptn + θld ... [Formula 4]
According to the above equation 4, during intake stroke injection, θptn ≦ −Δθax1 and θld ≦ 0, so the fuel injection timing θinj is smaller than the basic fuel injection timing θainj. For this reason, the actual fuel injection timing set based on the fuel injection timing θinj in step S218 is delayed from the basic fuel injection timing θainj, and the smoke amount Smptn is suppressed to the smoke allowable amount smax or less.
[0152]
Further, at the time of compression stroke injection, θptn ≧ Δθbx1 and θld ≧ 0, so that the fuel injection timing θinj is larger than the basic fuel injection timing θainj. For this reason, the actual fuel injection timing set based on the fuel injection timing θinj in step S218 is advanced from the basic fuel injection timing θainj, and the smoke amount Smptn is suppressed to be equal to or less than the smoke allowable amount smax.
[0153]
In the above-described configuration, the fuel injection timing control process (FIG. 4) corresponds to a process as a smoke physical quantity calculation unit and a fuel injection timing correction unit.
According to the second embodiment described above, the following effects can be obtained.
[0154]
(I). Smoke in the burned gas is generated by adhesion of liquid fuel to the piston top surface 6a. The position of the piston top surface 6a at the time of the compression stroke injection is located at a position farther from the fuel injection valve 12 as the injection timing is earlier. Therefore, by correcting the advance angle of the basic fuel injection timing θainj based on the smoke amount Smptn in the burned gas, the piston top surface 6a can be separated from the fuel injection valve 12 at the fuel injection timing θinj, and to the piston top surface 6a. Of liquid fuel can be suppressed. As a result, the amount of smoke in the exhaust and smoke pollution of the intake system can be suppressed.
[0155]
Further, at the time of intake stroke injection, the basic fuel injection timing θainj is retarded based on the smoke amount Smptn. This increases the distance between the fuel injection valve 12 and the piston top surface 6a even during the intake stroke injection, and reduces the amount of liquid fuel adhering to the piston top surface 6a. Thus, by executing the advance angle correction during the compression stroke injection and the retard angle correction during the intake stroke injection, it is possible to more effectively suppress the smoke amount in the exhaust gas and the smoke contamination of the intake system.
[0156]
(B). By using the data of the fuel pressure Pf, the engine cooling water temperature THW, and the engine speed NE, which are the change factors of the piston adhering fuel amount Fptn on the piston top surface 6a, as described above, the piston adhering fuel amount Fptn is accurately estimated. . Therefore, the smoke amount Smptn generated corresponding to the piston adhering fuel amount Fptn can also be accurately estimated, and the fuel injection timing can be appropriately corrected. Therefore, it is possible to more appropriately suppress the amount of smoke in the exhaust and smoke contamination of the intake system.
[0157]
(C). Assuming that the amount of fuel adhering to the piston Fptn increases according to the travel distance Ld from when the engine 2 is in a new state, the correction value θld is obtained, and the basic fuel injection timing θainj together with the correction value θptn corresponding to the smoke amount Smptn. Is corrected.
[0158]
This travel distance Ld corresponds to the cumulative operation time of the engine 2. As the accumulated operation time of the engine 2 becomes longer, as described above, the piston top surface 6a is fouled by smoke, the surface property changes, and the piston adhering fuel amount Fptn also increases. Therefore, by adding the correction value θld reflecting this change to the correction, it is possible to more appropriately suppress the amount of smoke in the exhaust and smoke contamination of the intake system.
[0159]
[Embodiment 3]
In the present embodiment, taking into account that the engine temperature greatly affects the amount of fuel adhering to the piston, processing for correcting the fuel injection timing is performed based on the engine temperature. In the present embodiment, a fuel injection timing control process shown in FIG. 15 is executed instead of the fuel injection timing control process (FIG. 2) of the first embodiment. The other configuration is the same as that of the first embodiment.
[0160]
The fuel injection timing control process (FIG. 15) will be described. This process is repeatedly executed at the same crank angle cycle as the fuel injection timing control process (FIG. 2). When this process is started, first, the currently detected engine speed NE, load factor eklq, and engine coolant temperature THW are read (S302).
[0161]
Next, in the same manner as in step S104 (FIG. 2), the basic fuel injection timing θainj is calculated from the basic fuel injection timing map based on the load factor eklq and the engine speed NE (S304).
[0162]
Next, it is determined whether or not the engine 2 is cold (S306). In this determination, if the engine coolant temperature THW is lower than the reference temperature Hot for determining warm-up, it is determined that the engine is cold, and if the engine coolant temperature THW is equal to or higher than the reference temperature Hot, it is determined that the engine is not warm but not warm.
[0163]
If the engine 2 is not cold (“NO” in S306), the basic fuel injection timing θainj obtained in step S304 is set as the fuel injection timing θinj (S308). Then, the actual fuel injection timing is set based on the fuel injection timing θinj (S316), and this process is temporarily terminated.
[0164]
On the other hand, if it is cold (“YES” in S306), a correction value θthw corresponding to the fuel injection mode and the engine coolant temperature THW is calculated (S310). The correction value θthw is expressed as an advance correction value.
[0165]
Here, the relationship between the fuel injection timing and the smoke concentration Smdty in the engine 2 after warm-up is shown by a solid line in FIG. As described with reference to FIG. 3, this relationship includes a fuel injection timing region where the smoke concentration Smdty is small, and this fuel injection timing region deviates to the advance side during the intake stroke, or deviates to the retard side during the compression stroke. If this happens, the smoke concentration Smdty increases rapidly. In the cold state, the smoke concentration Smdty rises as shown by the one-dot chain line in FIG.
[0166]
The basic fuel injection timing θainj obtained in step S304 is set in a range where the smoke concentration Smdty is equal to or less than the smoke allowable concentration smdmax after warm-up. Here, it is assumed that when the basic fuel injection timing θainj is in the intake stroke, the smoke concentration Smdty after warm-up is set to the fuel injection timing θsa3 that is equal to or lower than the smoke allowable concentration smdmax (= Sa3). At this time, if the smoke concentration Smdty is actually cold as indicated by the one-dot chain line, the actual smoke concentration Smdty = Saa3> smdmax. Further, it is assumed that when the basic fuel injection timing θainj is in the compression stroke, the smoke concentration Smdty after warm-up is set to the fuel injection timing θsb3 that is equal to or less than the smoke allowable concentration smdmax (= Sb3). At this time, if the smoke concentration Smdty is actually cold as indicated by the one-dot chain line, the actual smoke concentration Smdty = Sbb3> smdmax is obtained.
[0167]
Therefore, in order to obtain the same smoke concentration Smdty as that after warm-up, it is necessary to correct the retardation of the width of Δθsax3 during the intake stroke injection with respect to the basic fuel injection timing θainj, and the width of Δθsbx3 during the compression stroke injection. It is necessary to correct the advance angle.
[0168]
Therefore, in step S310, the engine cooling water temperature THW and the basic temperature are calculated using the correction value θthw map using the engine cooling water temperature THW and the basic fuel injection timing θainj as parameters as shown in FIG. A correction value θthw is calculated based on the fuel injection timing θainj. The correction value θthw is set to “0” for the basic fuel injection timing θainj in a range that does not affect the smoke concentration Smdty even when cold.
[0169]
Next, a correction value θne corresponding to the value of the fuel injection mode and the engine speed NE is calculated (S312). The correction value θne is expressed as an advance correction value. The correction value θne is calculated based on the fuel injection mode and the engine speed NE from the correction value θne map using the fuel injection mode and the engine speed NE shown in FIG. 17 as parameters. Note that the tendency of the correction value θne in FIG. 17 is as described in FIG. 10 of the second embodiment. However, the correction value θne = “0” is set for the basic fuel injection timing θainj that does not affect the smoke concentration Smdty even when cold.
[0170]
When the two correction values θthw and θne are set in this way, the fuel injection timing θinj is set by the following equation 5 (S314).
[0171]
[Equation 5]
θinj ← θainj + θthw + θne ... [Formula 5]
According to the above equation 5, θthw ≦ 0 and θne ≦ 0 at the time of intake stroke injection, so that the fuel injection timing θinj is equal to or less than the basic fuel injection timing θainj. Therefore, the actual fuel injection timing set based on the fuel injection timing θinj in step S316 is the same as or retarded from the basic fuel injection timing θainj, and the smoke concentration Smdty is suppressed to be equal to or less than the smoke allowable concentration smdmax. The
[0172]
In addition, since θthw ≧ 0 and θne ≧ 0 during the compression stroke injection, the fuel injection timing θinj is equal to or greater than the basic fuel injection timing θainj. Therefore, the actual fuel injection timing set based on the fuel injection timing θinj in step S316 is the same as or advanced from the basic fuel injection timing θainj, and the smoke concentration Smdty is suppressed to be equal to or less than the smoke allowable concentration smdmax. The
[0173]
In the configuration described above, the fuel injection timing control process (FIG. 15) corresponds to the process as the fuel injection timing correction means.
According to the third embodiment described above, the following effects can be obtained.
[0174]
(I). The engine temperature (here, engine cooling water temperature THW) affects the amount of liquid fuel adhering to the piston top surface 6a because it affects the vaporization of the injected fuel and the liquid fuel vaporization at the piston top surface 6a. This affects the degree of smoke generation. Therefore, the distance between the fuel injection valve 12 and the piston top surface 6a during fuel injection is increased by correcting the advance angle of the fuel injection timing based on the engine temperature during the compression stroke injection. From this, the amount of liquid fuel adhering to the piston top surface 6a is suppressed, the increase in smoke concentration can be suppressed, and the smoke amount in the exhaust and smoke contamination of the intake system can be appropriately suppressed.
[0175]
Further, in addition to the advance angle correction during the compression stroke injection based on the engine temperature, the retard angle correction during the intake stroke injection is performed based on the engine temperature. As a result, the distance between the fuel injection valve 12 and the piston top surface 6a can be adjusted even during the intake stroke injection, and the amount of liquid fuel adhering to the piston top surface 6a can be reduced. In this way, by performing both the advance angle correction during the compression stroke injection and the retard angle correction during the intake stroke injection based on the engine temperature, the amount of liquid fuel adhering to the piston top surface 6a is effectively suppressed. Thus, the increase in smoke concentration can be suppressed, and the amount of smoke in the exhaust gas and smoke contamination of the intake system can be suppressed more appropriately.
[0176]
(B). As described in the second embodiment, the engine speed NE affects the moving speed of the piston 6 and therefore affects the amount of liquid fuel adhering to the piston top surface 6a. Accordingly, the fuel injection timing is corrected based on the engine speed NE as described above. As a result, the amount of liquid fuel adhering to the piston top surface 6a can be suppressed, the increase in smoke concentration can be suppressed, and the smoke amount in the exhaust and smoke contamination of the intake system can be suppressed more appropriately.
[0177]
[Embodiment 4]
In the present embodiment, the fuel injection timing is corrected based on the valve overlap period when it is determined that the operating state is a large intake port blowback smoke amount. In the present embodiment, the fuel injection timing control process shown in FIGS. 19 and 20 is executed instead of the fuel injection timing control process (FIG. 2) of the first embodiment. The other configuration is the same as that of the first embodiment.
[0178]
The fuel injection timing control process (FIGS. 19 and 20) will be described. This process is repeatedly executed at the same crank angle cycle as the fuel injection timing control process (FIG. 2). When this process is started, first, the currently detected engine speed NE, load factor eklq, intake air amount Ga, engine coolant temperature THW, and valve overlap period Lovr (expressed by crank angle width) are read. (S402). The valve overlap period Lovr is read because the ECU separately reads the valve timings of the intake and exhaust valves 2a and 2b and constantly calculates them. When the valve overlap period Lovr is not always calculated, the valve timing of the intake / exhaust valves 2a and 2b may be read to calculate the valve overlap period Lovr in this process.
[0179]
Next, as in step S104 (FIG. 2) of the first embodiment, the basic fuel injection timing θainj is calculated from the basic fuel injection timing map based on the load factor eklq and the engine speed NE (S404). Then, similarly to step S106 (FIG. 2), the intake pressure Pi at the intake port 16 is calculated from the intake air amount Ga and the engine speed NE (S406).
[0180]
Next, it is determined whether the engine coolant temperature THW is equal to or lower than the low temperature reference value THWL (S408). This low-temperature reference value THWL determines the extent to which the amount of smoke in the intake port increases when the amount of smoke in the burnt gas increases due to the low engine temperature and the burnt gas blows back into the intake system. This is a determination value provided for this purpose.
[0181]
Here, if THW> THWL (“NO” in S408), then a fuel injection timing attenuation process (S450: FIG. 20), which is a part of the fuel injection timing control process, is executed.
[0182]
In the fuel injection timing attenuation process (FIG. 20), it is first determined whether or not the injection timing correction execution flag Finj is “ON” (S452). The injection timing correction execution flag Finj is a flag indicating that the injection timing correction is being executed to suppress the smoke amount, but Finj = “OFF” in the initial setting. From this ("NO" in S452), the process returns to the process of FIG. 19, and the basic fuel injection timing θainj obtained in step S404 is set as the fuel injection timing θinj (S424). Then, the actual fuel injection timing is set based on the fuel injection timing θinj (S420), and this process is temporarily terminated.
[0183]
On the other hand, if THW ≦ THWL (“YES” in S408), it is determined whether the intake pressure Pi is equal to or lower than the low intake pressure reference value PL (S410). This low intake pressure reference value PL is a determination value provided to determine the extent to which the amount of burned gas blown back into the intake system increases due to the low intake pressure Pi.
[0184]
Here, if Pi> PL (“NO” in S410), then the injection timing correction execution flag Finj is set to “OFF” (S422), and the basic fuel injection timing θainj is set to the fuel injection timing θinj (S424). ). Then, the actual fuel injection timing is set based on the fuel injection timing θinj (S420), and this process is temporarily terminated.
[0185]
On the other hand, if Pi ≦ PL (“YES” in S410), it is next determined whether or not the engine speed NE is equal to or lower than the low speed reference value NEL (S412). The low engine speed reference value NEL is a determination value provided to determine the extent to which the amount of burned gas blown back into the intake system increases due to the low engine speed NE.
[0186]
If NE> NEL (“NO” in S412), “OFF” is set to the injection timing correction execution flag Finj (S422), and the basic fuel injection timing θainj is set to the fuel injection timing θinj (S424). The actual fuel injection timing is set based on the fuel injection timing θinj (S420), and this process is temporarily terminated.
[0187]
As described above, in the state of Finj = “OFF”, if THW> THWL (“NO” in S408), Pi> PL (“NO” in S410), or NE> NEL (“NO” in S412), The injection timing correction for suppressing the intake port blowback smoke amount is not executed.
[0188]
When it is determined that NE ≦ NEL, that is, THW ≦ THWL (“YES” in S408), Pi ≦ PL (“YES” in S410), and NE ≦ NEL (“YES” in S412), Next, “ON” is set to the injection timing correction execution flag Finj (S414).
[0189]
Based on the fuel injection mode, the basic fuel injection timing θainj, and the valve overlap period Lovr, the fuel injection timing correction value θovr is obtained from a map prepared in advance by experiments (S416). The map of the fuel injection timing correction value θovr is as shown in FIG. That is, as the valve overlap period Lovr becomes longer during the intake stroke injection, the retard angle correction (θovr ≦ 0) becomes larger, and during the compression stroke injection, the advance angle correction (θovr ≧ 0) becomes larger as the valve overlap period Lovr becomes longer. As described above, it is set in advance by experiment or model calculation. This is because if the valve overlap period Lovr becomes longer, the burnt gas flowing out to the exhaust system (exhaust port 32 and exhaust passage 36) through the combustion chamber 10 again becomes the intake system (intake port 16 and intake passage 20) side. This is because the degree of inflow into the water increases. This is dealt with by suppressing the amount of smoke by reducing the amount of liquid fuel adhering to the piston top surface 6a.
[0190]
When the fuel injection timing correction value θovr is calculated in this way, the fuel injection timing θinj is calculated by correcting the basic fuel injection timing θainj with the fuel injection timing correction value θovr as shown in the following equation 6 (S418). ).
[0191]
[Formula 6]
θinj ← θainj + θovr ... [Formula 6]
Then, the actual fuel injection timing is set based on the fuel injection timing θinj (S420), and this process is temporarily terminated. As a result, the amount of smoke that enters the intake system by riding on the burnt burned gas is reduced, and smoke pollution of the intake system can be effectively suppressed.
[0192]
A case where any of the conditions of steps S408, S410, and S412 is no longer satisfied from the state in which the basic fuel injection timing θainj is corrected by the fuel injection timing correction value θovr in this way will be described. If Pi> PL (“NO” in S410) or NE> NEL (“NO” in S412), the injection timing correction execution flag Finj is returned to “OFF” (S422). Then, the basic fuel injection timing θainj is set as the fuel injection timing θinj (S424), the actual fuel injection timing is set based on the fuel injection timing θinj (S420), and this process is temporarily terminated. As a result, the fuel injection timing correction value θovr is not corrected.
[0193]
When THW> THWL (“NO” in S408) from the state where the basic fuel injection timing θainj is corrected by the fuel injection timing correction value θovr, the fuel injection timing correction attenuation process (FIG. 20) First, Finj = “ON” (“YES” in S452). Accordingly, next, the absolute value of the fuel injection timing correction value θovr is decreased by the attenuation value dθ (S454). That is, at the time of intake stroke injection and θovr ≦ 0, the attenuation value dθ is added as shown in the following equation 7.
[0194]
[Expression 7]
θovr ← θovr + dθ ... [Formula 7]
When the compression stroke injection is performed and θovr ≧ 0, the attenuation value dθ is subtracted as shown in the following equation (8).
[0195]
[Equation 8]
θovr ← θovr−dθ [Equation 8]
Here, the attenuation value dθ is a value for gradually attenuating the fuel injection timing correction value θovr every control cycle. When the absolute value of the fuel injection timing correction value θovr is smaller than dθ, “0” is set to the fuel injection timing correction value θovr.
[0196]
If the absolute value of the fuel injection timing correction value θovr is decreased in the equation 7 or the equation 8, it is next determined whether or not the fuel injection timing correction value θovr is “0” (S456). If θovr ≠ “0” (“NO” in S456), the fuel injection timing θinj is calculated by correcting the basic fuel injection timing θainj with the fuel injection timing correction value θovr in the same processing as the above equation 6. (S460).
[0197]
Then, in step S420 in FIG. 19, the actual fuel injection timing is set based on the fuel injection timing θinj, and this process is temporarily terminated. Thus, fuel injection is executed at the fuel injection timing θinj corrected by the fuel injection timing correction value θovr attenuated by this.
[0198]
Thereafter, as long as THW> THWL (“NO” in S408) and the fuel injection timing correction value θovr ≠ 0 in the calculation in step S454 (“NO” in S456), the fuel injection timing correction is gradually attenuated. Fuel injection is executed at the fuel injection timing θinj corrected by the value θovr.
[0199]
When θovr = 0 (“YES” in S456), the injection timing correction execution flag Finj is returned to “OFF” (S458). Therefore, in the next control cycle, “NO” is determined in step S408, and “NO” is determined in step S452, and step S424 is executed. Therefore, the fuel injection timing correction for suppressing the intake port blowback smoke amount is not performed.
[0200]
In the configuration described above, the process of reading the valve timings of the intake / exhaust valves 2a and 2b and calculating the valve overlap period Lovr corresponds to the process as the valve overlap detection means. The fuel injection timing control process (FIGS. 19 and 20) corresponds to a process as a smoke blow-back state determination unit and a fuel injection timing correction unit.
[0201]
According to the fourth embodiment described above, the following effects can be obtained.
(I). As described in the first embodiment, when the intake valve 2a and the exhaust valve 2b are configured as variable valve systems, the valve timing is adjusted according to the engine operating state. Even if the period is long, there is not always a possibility of smoke pollution of the intake system. In other words, when the amount of smoke blown back to the intake system is small, there is no problem with the smoke contamination of the intake system regardless of the valve overlap period, but when the operation state with a large amount of smoke blown back to the intake system is reached, the intake system depends on the valve overlap period. There is a risk of smoke pollution.
[0202]
Therefore, at the time of compression stroke injection, when the engine temperature is low, the intake pressure is low, and the engine speed is low (“YES” in S408, S410, and S412), the engine operating state increases the amount of smoke blown back into the intake system. Determination is made, and the fuel injection timing is corrected to advance more as the valve overlap period Lovr becomes longer. As a result, the smoke pollution of the intake system can be accurately suppressed, and the advance angle correction for suppressing the pollution of the intake system is performed under limited conditions, so that the engine performance can be easily maintained at a high level.
[0203]
Further, at the time of the intake stroke injection, the fuel injection timing is largely retarded as the valve overlap period Lovr becomes longer at low engine temperature, low intake pressure, and low engine speed (“YES” in S408, S410, and S412). ing. As a result, even during intake stroke injection, smoke pollution of the intake system can be accurately suppressed, and the retard angle correction for suppressing contamination of the intake system is performed under limited conditions, so the engine performance is high. Easy to maintain.
[0204]
(B). When the engine coolant temperature THW rises and becomes higher than the low temperature reference value THWL, the correction amount is gradually attenuated instead of immediately stopping the correction of the fuel injection timing. For this reason, it is possible to prevent a shock due to a sudden change in the fuel injection timing when the correction of the fuel injection timing is stopped due to the engine temperature rise from the cold time.
[0205]
[Embodiment 5]
The present embodiment is different from the fourth embodiment in that the fuel injection timing correction attenuation process shown in FIG. 22 is executed instead of the fuel injection timing correction attenuation process (FIG. 20). Other configurations are the same as those of the fourth embodiment.
[0206]
The fuel injection timing correction attenuation process (FIG. 22) will be described. As described in the fourth embodiment, this process is executed when it is determined in the fuel injection timing control process (FIG. 19) that the engine coolant temperature THW> the low temperature reference value THWL (“NO” in S408). .
[0207]
First, it is determined whether or not the injection timing correction execution flag Finj is “ON” (S502). Since Finj = “OFF” in the initial setting (“NO” in S502), the process returns to the process of FIG. 19, and the basic fuel injection timing θainj obtained in step S404 is set as the fuel injection timing θinj ( S424). Then, the actual fuel injection timing is set based on the fuel injection timing θinj (S420), and this process is temporarily terminated.
[0208]
When THW> THWL (“NO” in S408) from the state in which the fuel injection timing correction is performed by the fuel injection timing correction value θovr, the first in the fuel injection timing correction attenuation process (FIG. 22) Since Finj = “ON” (“YES” in S502), the attenuation correction value θx is calculated by the following equation 9 (S504).
[0209]
[Equation 9]
θx ← θovr × (THWh-THW) / (THWh-THWL) ... [Formula 9]
Here, the high temperature determination temperature THWh is set as an engine coolant temperature higher than the low temperature reference value THWL, and the fuel vaporized from the fuel injection valve 12 and the fuel adhering to the piston top surface 6a are rapidly vaporized. This is the engine cooling water temperature at which the amount of smoke blown back into the intake system becomes no problem. In the equation 9, when THW ≧ THWh, “0” is set as the attenuation correction value θx.
[0210]
Initially, since the engine coolant temperature THW is slightly higher than the low temperature reference value THWL, the attenuation correction value θx is set to a slightly smaller value as an absolute value than the fuel injection timing correction value θovr according to the above equation 9. The
[0211]
Next, it is determined whether θx = “0” (S506). If θx ≠ “0” (“NO” in S506), the fuel injection timing θinj is calculated by correcting the basic fuel injection timing θainj with the attenuation correction value θx by the following equation 10 (S510).
[0212]
[Expression 10]
θinj ← θainj + θx ... [Formula 10]
Then, in step S420 in FIG. 19, the actual fuel injection timing is set based on the fuel injection timing θinj, and this process is temporarily terminated. Thus, the fuel injection timing is corrected by the attenuation correction value θx attenuated in response to the increase in the engine coolant temperature THW.
[0213]
In the subsequent control cycle, every time the engine coolant temperature THW increases, the absolute value of the attenuation correction value θx calculated by the equation 9 becomes smaller. Therefore, as long as the attenuation correction value θx ≠ 0 (“ NO "), the fuel injection timing is corrected by the attenuation correction value θx that is gradually attenuated.
[0214]
When θx = 0 in the process of step S504 (“YES” in S506), the injection timing correction execution flag Finj is returned to “OFF” (S508). Accordingly, in the next control cycle, “NO” is determined in the step S502, and the step S424 in FIG. 18 is executed. Therefore, the fuel injection timing correction for suppressing the intake port blowback smoke amount is not performed.
[0215]
In the above-described configuration, the fuel injection timing control process (FIGS. 19 and 22) corresponds to a process as a smoke blow-back state determination unit and a fuel injection timing correction unit.
According to the fifth embodiment described above, the following effects can be obtained.
[0216]
(I). The effect (a) of the fourth embodiment is produced.
(B). Since the correction of the fuel injection timing is also attenuated in accordance with the increase in the engine coolant temperature THW, the fuel injection timing can be more adapted to the engine operating state, and engine shock can be prevented.
[0217]
[Embodiment 6]
The present embodiment is different from the fifth embodiment in that the fuel injection timing control process shown in FIGS. 23 and 24 is executed instead of the fuel injection timing control process (FIGS. 19 and 22). Other configurations are the same as those of the fifth embodiment. Also, steps S602 to S622 in FIG. 23 are the same as steps S402 to S422 in FIG. The difference is that a process (S623) of setting “0” to the correction amount θy described later is executed immediately after step S622. In step S624 instead of step S424 in FIG. 19, the fuel injection timing θinj is calculated by the following equation 11.
[0218]
## EQU11 ##
θinj ← θainj + θy ... [Formula 11]
The difference between the fuel injection timing correction attenuation process (FIG. 24) and FIG. 22 is that the fuel injection mode and the correction according to the increase in the valve overlap period Lovr corresponding to the increase in the engine coolant temperature THW from the low temperature reference value THWL. The amount θy is calculated. Further, instead of calculating the fuel injection timing θinj in step S510 of FIG. 22, the fuel injection timing θinj is calculated by the processing of the following equation 12.
[0219]
[Expression 12]
θinj ← θainj + θx + θy ... [Formula 12]
Note that the setting of the valve overlap period Lovr executed by the ECU is smaller in the cold state than after the warm-up. As the engine coolant temperature THW increases, the valve overlap period Lovr is increased to a normal size.
[0220]
Therefore, in the valve overlap period Lovr when THW ≦ THWL, even when the amount of smoke blown back into the intake system is not a problem, the valve overlap period Lovr increases as the engine coolant temperature THW becomes higher than the low temperature reference value THWL. There is a possibility that the amount of smoke blown back becomes a problem. In order to cope with the increase in the valve overlap period Lovr, a correction amount θy is provided.
[0221]
Accordingly, when THW> THWL is satisfied from the state in which the fuel injection timing correction has been performed by the fuel injection timing correction value θovr in the process of step S618 (“NO” in S608), the fuel injection timing correction attenuation process (FIG. 24). Is executed, the correction amount θy functions.
[0222]
That is, first, the correction amount θy is calculated according to the increase in the valve overlap period Lovr corresponding to the increase in the engine coolant temperature THW from the low temperature reference value THWL (S651). This correction amount θy is calculated from a map as shown in FIG. 25 created by experiments and model calculation based on the fuel injection mode and the valve overlap period Lovr after THW> THWL.
[0223]
At this time, since Finj = “ON” (“YES” in S652), the attenuation correction value θx is calculated as shown in the equation 9 (S654). If the attenuation correction value θx ≠ “0”, (“NO” in S656), the calculation of Equation 12 is executed (S660). Therefore, the fuel injection timing θinj is corrected by the attenuation correction value θx and the correction amount θy accompanying the increase in the valve overlap period.
[0224]
Thereafter, as the engine coolant temperature THW increases, the attenuation correction value θx decreases, but the correction amount θy increases. When the attenuation correction value θx = “0” (“YES” in S656), “OFF” is set to the injection timing correction execution flag Finj (S658). In the next calculation of Equation 12, θx = “0”, so that the fuel injection timing is corrected substantially by the correction amount θy (S660).
[0225]
In the next control cycle, after “NO” is calculated in step S608 and the correction amount θy is calculated (S651), “NO” is determined in step S652, and step S624 is executed. Here, the fuel injection timing correction of only the correction amount θy is performed by the above equation 11. Therefore, thereafter, the correction amount θy corresponding to the valve overlap period Lovr corresponding to the increase in the engine coolant temperature THW is reflected in the fuel injection timing θinj.
[0226]
In the configuration described above, the fuel injection timing control process (FIGS. 23 and 24) corresponds to the process as the smoke blow-back state determination means and the fuel injection timing correction means.
According to the sixth embodiment described above, the following effects can be obtained.
[0227]
(I). The effects (a) and (b) of the fifth embodiment are produced.
(B). Here, since the valve overlap period Lovr is increased in accordance with the increase in the engine coolant temperature THW, a large amount of burned gas may be blown into the intake system after the engine coolant temperature THW is increased. Therefore, by correcting the fuel injection timing in accordance with the increase in the valve overlap period Lovr accompanying the increase in the engine coolant temperature THW, it is possible to more accurately suppress the smoke pollution of the intake system.
[0228]
[Other embodiments]
(A). The engine 2 in FIG. 1 uses the intake variable valve mechanism 43 and the exhaust variable valve mechanism 45, but may be an engine configured as a system that adjusts the valve overlap period using either one.
[0229]
(B). In each of the above embodiments, the engine coolant temperature THW is used as the engine temperature, but the temperature of the engine oil may be used instead. Further, the combustion chamber temperature of the engine and the piston top surface temperature may be estimated from the operating state of the engine and used.
[0230]
(C). The engine 2 in FIG. 1 is a four-cylinder engine. However, when the engine 2 has a different number of cylinders, the interruption cycle of each control process is different. For example, in the case of a 6-cylinder engine, each control process is executed every 120 ° CA.
[0231]
(D). In the second embodiment, the correction value θld is determined according to the travel distance Ld of the vehicle. However, the correction value θld is determined according to the total operation time of the engine 2 or according to the total number of revolutions of the engine 2. Also good.
[0232]
(E). In the process of FIG. 19, not only when THW> THWL (“NO” in S408), but also when Pi> PL (“NO” in S410) or NE> NEL (“NO” in S412). Instead of step S422, a fuel injection timing correction attenuation process (FIG. 20) may be executed.
[0233]
(F). In Embodiments 4 to 6, the fuel injection mode and the valve overlap are satisfied when any one or two conditions are satisfied instead of all the conditions of THW ≦ THWL, Pi ≦ PL, and NE ≦ NEL. The fuel injection timing may be corrected by the fuel injection timing correction value θovr corresponding to the period Lovr. However, the fuel injection timing correction attenuation process of FIGS. 22 and 24 is executed when the fuel injection timing is corrected by satisfying at least THW ≦ THWL.
[0234]
(G). Of the equation 2 for obtaining the piston adhering fuel amount Fptn, the liquid fuel reaching amount Fin may be obtained based on the relationship of the following equation 13 instead of using a map. That is, the magnitude relation between the left side (movement distance of the piston top surface 6a) and the right side (liquid fuel reach distance in the piston direction) of the following equation 13 is repeatedly calculated at short intervals during the required time tv for the injected fuel. The liquid fuel arrival amount Fin may be obtained based on the length of time satisfying the relationship of 13.
[0235]
[Formula 13]

This expression 13 represents the relationship when the liquid fuel reaches the piston top surface 6a. Here, θ (t) is the change in crank angle with time, Vp (NE, θ (t)) is the moving speed of the piston 6, Vs is the tip speed of the injected fuel, and α is the injection angle (FIG. 1). Further, the time required for vaporizing the injected fuel (the time from when the fuel is injected until the liquid fuel is completely vaporized) tv is given as a function of the engine coolant temperature THW.
[0236]
(H). In the first embodiment, the ECU 4 sequentially executes calculations for finally obtaining the correction value θsm from the data read in step S102. Instead, a map using the above-mentioned data used as a parameter for obtaining the correction value θsm is obtained in advance by the calculation described in the first embodiment and stored in a memory such as a ROM in the ECU 4. Also good. Accordingly, when the correction value θsm is necessary, the correction value θsm is obtained from the map based on the data read in step S102. Similarly, the intake port blow-back smoke amount Smret is preliminarily constructed as a map by the calculation described in the first embodiment and stored in a memory such as a ROM, and the intake air is drawn based on the data read in step S102 from this map. The port blow-back smoke amount Smret may be obtained.
[0237]
Further, the value of “θainj + θsm” itself is obtained in advance by the calculation described in the first embodiment as a map using the data read in step S102 as a parameter, and is stored in a memory such as a ROM in the ECU 4. Also good. Therefore, when the fuel injection timing θinj is necessary, the fuel injection timing θinj is obtained from the map based on the data read in step S102.
[0238]
Also in the second embodiment, as described above, the correction value θptn, the smoke amount Smptn, or the fuel injection timing θinj is mapped by the calculation described in the second embodiment, and based on the data read in step S202 from this map. You may ask. Similarly, the correction value map in which the correction value θptn and the correction value θld are combined into one, and the calculation described in the second embodiment using each data used for obtaining the correction value θptn and the correction value θld in advance as parameters. It may be obtained by the above and stored in a memory such as a ROM in the ECU 4. Then, when necessary, a correction value obtained by combining the correction value θptn and the correction value θld based on the data read in step S202 may be obtained from the map and used.
[0239]
Also in the third embodiment, as described above, the correction values θthw, θne, θthw + θne, or the fuel injection timing θinj are mapped by the calculation described in the third embodiment, and the data read in step S302 from this map You may ask based on.
[0240]
Also in the fourth, fifth, and sixth embodiments, as described above, the correction value θovr or the fuel injection timing θinj is mapped by the calculation described in the fourth, fifth, and sixth embodiments, and from this map to steps S402 and S602. You may obtain | require based on the data read.
[0241]
By configuring each embodiment by map processing as described above, the load on the ECU can be suppressed. For this reason, a cheap thing can be utilized for arithmetic units, such as CPU used for ECU, or a process can be speeded up.
[Brief description of the drawings]
FIG. 1 is a schematic system diagram of an in-cylinder injection engine and an ECU according to a first embodiment.
FIG. 2 is a flowchart of a fuel injection timing control process executed by the ECU.
FIG. 3 is a graph showing the relationship between fuel injection timing and smoke concentration Smdty for explaining fuel injection timing correction processing according to the first embodiment;
FIG. 4 is a flowchart of fuel injection timing control processing according to the second embodiment.
FIG. 5 is a timing chart showing the positional relationship between the injected fuel and the piston top surface according to the difference in fuel pressure Pf.
FIG. 6 is a timing chart showing the positional relationship between the injected fuel and the piston top surface according to the difference in engine coolant temperature THW.
FIG. 7 is a timing chart showing the positional relationship between the injected fuel and the piston top surface according to the difference in engine speed NE.
FIG. 8 is an explanatory diagram of a map structure for obtaining a basic reach F0 based on a basic fuel injection timing θainj and a fuel pressure Pf for each fuel injection mode.
FIG. 9 is an explanatory diagram of a map structure for obtaining a temperature correction coefficient kthw based on the basic fuel injection timing θainj and the engine coolant temperature THW for each fuel injection mode.
FIG. 10 is an explanatory diagram of a map structure for obtaining a rotational speed correction coefficient knee based on a basic fuel injection timing θainj and an engine rotational speed NE for each fuel injection mode.
FIG. 11 is an explanatory diagram of a map structure for obtaining an injection time correction coefficient kinj from a fuel injection time Tinj.
FIG. 12 is an explanatory diagram of a map structure for obtaining a fuel vaporization amount Fout based on a basic fuel injection timing θainj and an engine coolant temperature THW.
FIG. 13 is a graph showing a relationship between a fuel injection timing and a smoke amount Smptn for explaining a fuel injection timing correction process according to the second embodiment.
FIG. 14 is an explanatory diagram of a map structure for calculating a correction value θld based on a travel distance Ld.
FIG. 15 is a flowchart of fuel injection timing control processing according to the third embodiment.
FIG. 16 is an explanatory diagram of a map structure for obtaining a correction value θthw based on the basic fuel injection timing θainj and the engine coolant temperature THW for each fuel injection mode.
FIG. 17 is an explanatory diagram of a map structure for obtaining a correction value θne based on the basic fuel injection timing θainj and the engine speed NE for each fuel injection mode.
FIG. 18 is a graph showing the relationship between fuel injection timing and smoke concentration Smdty for explaining fuel injection timing correction processing according to the third embodiment.
FIG. 19 is a flowchart of fuel injection timing control processing according to the fourth embodiment.
FIG. 20 is a flowchart of fuel injection timing correction attenuation processing according to the fourth embodiment.
FIG. 21 is an explanatory diagram of a map structure for obtaining a fuel injection timing correction value θovr based on a basic fuel injection timing θainj and a valve overlap period Lovr for each fuel injection mode.
FIG. 22 is a flowchart of fuel injection timing correction attenuation processing according to the fifth embodiment.
FIG. 23 is a flowchart of fuel injection timing control processing according to the sixth embodiment.
FIG. 24 is a flowchart of fuel injection timing correction attenuation processing according to the sixth embodiment.
FIG. 25 is an explanatory diagram of a map structure for obtaining a correction amount θy based on a basic fuel injection timing θainj and a valve overlap period Lovr for each fuel injection mode.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 2 ... Engine, 2a ... Intake valve, 2b ... Exhaust valve, 4 ... ECU, 6 ... Piston, 6a ... Piston top surface, 10 ... Combustion chamber, 12 ... Fuel injection valve, 14 ... Spark plug, 16 ... Intake port, 20 DESCRIPTION OF SYMBOLS ... Intake passage, 22 ... Surge tank, 24 ... Motor, 26 ... Throttle valve, 28 ... Throttle opening sensor, 30 ... Intake air amount sensor, 32 ... Exhaust port, 36 ... Exhaust passage, 38 ... Exhaust purification catalyst, 40 ... Fuel pressure sensor, 42 ... intake cam, 43 ... intake variable valve mechanism, 43a ... stroke sensor, 44 ... exhaust cam, 45 ... exhaust variable valve mechanism, 45a ... stroke sensor, 46 ... accelerator pedal, 48 ... accelerator Opening sensor, 50 ... engine speed sensor, 52 ... reference crank angle sensor, 54 ... cooling water temperature sensor, 56 ... air-fuel ratio sensor, 58 ... travel distance meter .

Claims (36)

A fuel injection timing control device for a direct injection engine that injects fuel into a combustion chamber,
Blowback amount calculation means for calculating the amount of burnt gas blowback from the combustion chamber to the intake system based on the operating state of the engine;
Fuel injection timing correction means for correcting the advance of the fuel injection timing when the injection timing is present in the compression stroke period based on the blowback amount of burned gas calculated by the blowback amount calculation means;
A fuel injection timing control device for a direct injection type engine. 2. The fuel injection timing correction means according to claim 1, wherein the fuel injection timing correction means advances the fuel injection timing when there is an injection timing in the compression stroke period based on the blowback amount of burned gas calculated by the blowback amount calculation means. A fuel injection timing control device for a direct injection type engine characterized by correcting the angle and retarding the fuel injection timing when the injection timing is present in the intake stroke period. A fuel injection timing control device for a direct injection engine that injects fuel into a combustion chamber,
Blowback amount calculation means for calculating the amount of burnt gas blowback from the combustion chamber to the intake system based on the operating state of the engine;
Fuel injection timing correction means for correcting the delay of the fuel injection timing when the injection timing exists in the intake stroke period based on the blowback amount of burned gas calculated by the blowback amount calculation means;
A fuel injection timing control device for a direct injection type engine. 4. The fuel injection timing correction unit according to claim 1, wherein the fuel injection timing correction unit obtains a smoke concentration of burned gas based on an operating state of the engine, and the smoke concentration and the blowback amount calculation unit calculate the smoke concentration. A fuel injection timing control device for a cylinder injection type engine, wherein the fuel injection timing is corrected based on a blowback amount of the fuel gas. In Claim 4, the fuel injection timing correction means obtains the amount of smoke blowback to the intake system based on the smoke concentration and the amount of burnt gas blowback calculated by the blowback amount calculation means, A fuel injection timing control device for a direct injection type engine, wherein the fuel injection timing is corrected so that the amount of smoke blowback falls within a reference range. 6. The fuel injection timing control device for a direct injection type engine according to claim 1, wherein the blowback amount calculation means calculates the blowback amount according to a valve overlap period. 6. The fuel injection timing control device for a direct injection engine according to claim 1, wherein the blowback amount calculation means calculates the blowback amount according to an intake pressure. The in-cylinder injection engine according to any one of claims 1 to 5, wherein the blow-back amount calculating means calculates the blow-back amount in accordance with a closing timing of the exhaust valve and a opening timing of the intake valve. Fuel injection timing control device. 6. The fuel injection timing control device for a direct injection type engine according to claim 1, wherein the blowback amount calculation means calculates the blowback amount according to the engine speed. 6. The fuel injection timing control device for a direct injection engine according to claim 1, wherein the blowback amount calculation means calculates the blowback amount according to a valve overlap period and an intake pressure. 6. The fuel injection for a direct injection engine according to claim 1, wherein the blowback amount calculation means calculates the blowback amount according to a valve overlap period, an intake pressure, and an engine speed. Timing control device. 6. The in-cylinder injection according to claim 1, wherein the blowback amount calculation means calculates the blowback amount according to a closing timing of the exhaust valve, a valve opening timing of the intake valve, and an intake pressure. Type fuel injection timing control device. 6. The blow-back amount calculating means according to claim 1, wherein the blow-back amount calculating means calculates the blow-back amount according to an exhaust valve closing timing, an intake valve opening timing, an intake pressure, and an engine speed. A fuel injection timing control device for an in-cylinder injection engine. The fuel injection timing control device for a direct injection engine according to any one of claims 6, 8, 10 to 13, wherein the blowback amount calculation means calculates the blowback amount to be larger as the valve overlap period becomes longer. . The fuel injection timing control device for a cylinder injection type engine according to any one of claims 7, 10 to 13, wherein the blowback amount calculation means calculates the blowback amount to be larger as the intake pressure becomes lower. The fuel injection timing control device for a cylinder injection type engine according to any one of claims 9, 11, and 13, wherein the blowback amount calculating means calculates the blowback amount larger as the engine speed is lower. A fuel injection timing control device for a direct injection engine that injects fuel into a combustion chamber,
A smoke physical quantity calculating means for calculating a physical quantity representing the smoke quantity in the burnt gas based on the operating state of the engine or a physical quantity reflecting the smoke quantity;
Fuel injection timing correction means for correcting the advance of the fuel injection timing based on the physical quantity calculated by the smoke physical quantity calculation means when the fuel injection timing is present in the compression stroke period;
A fuel injection timing control device for a direct injection type engine. In Claim 17, the fuel injection timing correction means corrects the advance of the fuel injection timing when the injection timing is present in the compression stroke period based on the physical quantity calculated by the smoke physical quantity calculation means, A fuel injection timing control device for a cylinder injection type engine, wherein when the injection timing exists in an intake stroke period, the fuel injection timing is retarded. The in-cylinder injection engine according to claim 17 or 18, wherein the smoke physical quantity calculating means calculates, as the physical quantity, an amount of fuel adhering to a piston top surface accompanying fuel injection based on an operating state of the engine. Fuel injection timing control device. 20. The fuel injection timing control device for a cylinder injection engine according to claim 17, wherein the smoke physical quantity calculation unit calculates the physical quantity according to a fuel injection pressure. 21. The fuel injection timing control device for a direct injection engine according to claim 20, wherein the smoke physical quantity calculating means calculates the physical quantity to be larger as the fuel injection pressure is higher. The fuel injection timing control device for a cylinder injection type engine according to any one of claims 17 to 19, wherein the smoke physical quantity calculation means calculates the physical quantity according to an engine speed. 23. The fuel injection for a cylinder injection type engine according to claim 22, wherein the smoke physical quantity calculating means calculates the physical quantity larger as the engine speed is higher when the injection timing is present in the compression stroke period. Timing control device. 23. The fuel injection for a direct injection engine according to claim 22, wherein the smoke physical quantity calculating means calculates the physical quantity to be larger as the engine speed is lower when the injection timing is present during the intake stroke period. Timing control device. 20. The fuel injection timing control device for a direct injection type engine according to claim 17, wherein the smoke physical quantity calculation unit calculates the physical quantity according to an engine temperature. 26. The fuel injection timing control device for a direct injection engine according to claim 25, wherein the smoke physical quantity calculating means calculates the physical quantity to be larger as the engine temperature is lower. A fuel injection timing control device for an in-cylinder injection engine that includes a variable valve system that adjusts a valve timing according to an operating state of an engine and injects fuel into a combustion chamber,
  Valve overlap detection means for detecting the valve overlap period;
  Smoke blow-back state determination means for determining whether or not the engine is in an operating state in which the amount of smoke blow-back to the intake system increases.
  When the fuel injection timing exists during the compression stroke period, if the smoke blow-back state determining means determines that the engine is in an engine operating state in which the amount of smoke blow-back to the intake system increases, the valve overlap detection means Fuel injection timing correction means for correcting the advance of the fuel injection timing based on the valve overlap period detected at
  A fuel injection timing control device for a direct injection type engine. The fuel injection timing correction means according to claim 27, wherein when the smoke blow back state determination means determines that the engine is in an engine operating state in which the amount of smoke blow back to the intake system increases, the valve overlap detection is performed. Based on the valve overlap period detected by the means, the fuel injection timing is advanced when the injection timing exists during the compression stroke period, and the fuel injection timing is retarded when the injection timing exists during the intake stroke period. A fuel injection timing control device for a direct injection type engine characterized by correcting. A fuel injection timing control device for an in-cylinder injection engine that includes a variable valve system that adjusts a valve timing according to an operating state of an engine and injects fuel into a combustion chamber,
  Valve overlap detection means for detecting the valve overlap period;
  Smoke blow-back state determination means for determining whether or not the engine is in an operating state in which the amount of smoke blow-back to the intake system increases.
  When the fuel injection timing exists during the intake stroke period, if the smoke blow-back state determining means determines that the engine is in an engine operating state in which the amount of smoke blow-back to the intake system increases, the valve overlap detecting means A fuel injection timing correction means for correcting the delay of the fuel injection timing based on the valve overlap period detected at
  A fuel injection timing control device for a direct injection type engine. 30. The fuel injection timing control device for a cylinder injection engine according to claim 27, wherein the fuel injection timing correction means corrects the fuel injection timing to a greater extent as the valve overlap period becomes longer. 31. The smoke blow-back state determination means according to claim 27, wherein the smoke blow-back state determination means smokes the intake system when one or more of the conditions of low rotation, low intake pressure and low engine temperature are satisfied. A fuel injection timing control device for an in-cylinder injection engine, characterized in that it is determined that the engine is in an operating state in which the amount of blow-back of the engine increases. In Claim 31, the fuel injection timing correction means is determined by the smoke blowback state determination means to be in an engine operating state in which the amount of smoke blowback to the intake system increases due to the low engine temperature condition being satisfied. A fuel injection timing control device for a cylinder injection type engine, wherein when the fuel injection timing is corrected, the correction to the fuel injection timing is gradually reduced in accordance with an increase in engine temperature. 33. The fuel injection timing correction means according to claim 31, wherein when the valve overlap period increases in response to an increase in engine temperature, the fuel injection timing correction means increases the correction in accordance with the increase in valve overlap period. A fuel injection timing control apparatus for a direct injection type engine. A correction value or correction of the fuel injection timing using as a parameter the engine operating state obtained by executing in advance the processing of the blowback amount calculation means and the fuel injection timing correction means according to any one of claims 1 to 16. A fuel injection timing control device for a cylinder injection type engine, wherein the fuel injection timing of the cylinder injection type engine is controlled using a map of the subsequent fuel injection timing. 27. A fuel injection timing correction value or correction using as a parameter the engine operating state obtained by executing the processing of the smoke physical quantity calculating means and the fuel injection timing correcting means in advance in any one of claims 17 to 26. In-cylinder injection type characterized by controlling fuel injection timing of in-cylinder injection type engine using map of subsequent fuel injection timing Engine fuel injection timing control device. 34. A fuel having as a parameter the operating state of the engine obtained by executing the processing of the valve overlap detecting means, the smoke blow-back state determining means and the fuel injection timing correcting means in any one of claims 27 to 33 in advance. A fuel injection timing control device for a cylinder injection type engine, wherein the fuel injection timing of the cylinder injection type engine is controlled using a correction value of the injection timing or a map of the corrected fuel injection timing.

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