JP2006194098A - Fuel injection control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase a combustion speed by securing an air-fuel mixture flow in an internal combustion engine including an in-cylinder injector and an intake passage injector.
SOLUTION: When combustion deterioration occurs in an operation region in which fuel injection is performed by being shared by in-cylinder injector 110 and intake passage injector 120, the fuel injection timing from in-cylinder injector 110 is set. Divide it into multiple times, and provide a part of it in the latter half of the intake stroke or the compression stroke. When the sharing ratio by the in-cylinder injector 110 is extremely small, the fuel injection amount from the in-cylinder injector 110 is secured by correcting the sharing ratio, and the fuel injection is executed in the latter half of the intake stroke or the compression stroke. .
[Selection] Figure 2

Description

  The present invention relates to a fuel injection control device for an internal combustion engine, and more specifically, in a first fuel injection means (in-cylinder injector) for injecting fuel into a cylinder and an intake passage and / or an intake port. The present invention relates to fuel injection control during homogeneous combustion operation in an internal combustion engine configured to include second fuel injection means (intake passage injection injector) for fuel injection.

  2. Description of the Related Art A configuration of an internal combustion engine that includes both an in-cylinder injector that directly injects fuel into a combustion chamber of an engine and an intake passage injector that injects fuel into an intake port is known. In order to suitably suppress that the in-cylinder injector is maintained at a high temperature when performing homogenous combustion operation of such an internal combustion engine, fuel injection from the in-cylinder injector in addition to the intake passage injector is also performed. (For example, patent document 1) is disclosed.

In addition, as a control device for a direct injection spark ignition engine in a cylinder, the fuel spray is subjected to gas flow in order to prevent the fuel spray from being pressed against the piston crown during homogeneous combustion operation. Thus, a technique is disclosed that is performed twice before and after the period of pressing against the crown surface of the piston (for example, Patent Document 2).
JP 2002-364409 A JP 2002-130025 A

  In Patent Document 1, the fuel injection timing from the in-cylinder injector is such that the engine speed and the target fuel injection amount are set so that the fuel and air are mixed well and the mixture is suitably homogenized. The electronic control is disclosed. In particular, it is disclosed that two fuel injection timings, that is, a relatively early timing and an end of the compression stroke, are calculated in an operation region where the engine speed is high and the target fuel injection amount is large. In Patent Document 1, the fuel injection timing is set based on the relationship between the engine speed and the target fuel injection amount, which are obtained through experiments, and the fuel injection timing at which the mixture is suitably homogenized.

  On the other hand, in the configuration in which the in-cylinder injector and the intake manifold injector are used in combination to perform the homogeneous combustion operation, the ratio of the fuel injection amount from both injectors is set according to the operating state of the engine. A configuration is preferred. In such a case, a method for improving the combustion state at the time of occurrence of combustion deterioration after basically following the sharing ratio set according to the operating state of the engine is required. In particular, in a region where the share ratio by the intake manifold injector is high, it tends to be difficult to ensure the air-fuel mixture flow in the combustion chamber, and thus the combustion tends to deteriorate.

  On the other hand, in the configuration disclosed in Patent Document 1, although the fuel injection timing is set according to the engine rotation speed and the target fuel injection amount according to a relationship set in advance based on experiments or the like, combustion deterioration occurs. There is no disclosure on how to improve combustion by changing the situation in the combustion chamber.

  Similarly, in the configuration disclosed in Patent Document 2, although the effect of preventing the occurrence of smoke when the operating condition of the engine is in the low rotation and high load period is obtained, when combustion deterioration occurs in the engine, There is no disclosure on how to improve combustion by changing the situation in the combustion chamber.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a first fuel injection means (in-cylinder injector) for injecting fuel into a cylinder, and In an internal combustion engine configured to include second fuel injection means (intake passage injection injector) for injecting fuel into the intake passage, air-fuel mixture flow (air flow formation) is ensured when combustion worsens. Another object of the present invention is to provide a fuel injection control device capable of improving the deterioration of combustion.

  The fuel injection control device for an internal combustion engine according to the present invention includes a first fuel injection means, a second fuel injection means, and a control means. The control means includes a share ratio control means, a combustion deterioration detection means, and a fuel injection timing control means. The first fuel injection means injects fuel into the cylinder of the internal combustion engine. The second fuel injection means injects fuel into the intake passage of the internal combustion engine. The control means controls the fuel supply from the first fuel injection means and the second fuel injection means based on conditions required for the internal combustion engine. The sharing ratio control unit controls the sharing ratio of the fuel injection amount between the first fuel injection unit and the second fuel injection unit with respect to the total fuel injection amount based on conditions required for the internal combustion engine. The combustion deterioration detection means detects combustion deterioration in the internal combustion engine. A fuel injection timing control means, and a share ratio is set so that at least a part of the total fuel injection amount is injected from the first fuel injection means by the share ratio control means, and combustion deterioration is caused by the combustion deterioration detection means. Is detected, the fuel injection timing of the first fuel injection means is controlled so that the fuel supply from the first fuel injection means is divided into a plurality of times. Further, the fuel injection timing control means sets at least a part of the supplied fuel divided into a plurality of times in at least one of the late intake stroke and the compression stroke.

  According to the fuel injection control device for an internal combustion engine, the fuel injection period from the first fuel injection means (in-cylinder injector) is divided into a plurality of times when the occurrence of combustion deterioration in the internal combustion engine is detected. Further, by providing at least a part of the divided fuel injection period in the late stage of the intake stroke or the compression stroke, it is possible to shorten the time from the fuel injection to the ignition timing and to enhance the air flow in the cylinder (combustion chamber) by fuel spray. . As a result, the combustion rate can be increased to improve the deterioration of combustion.

  Preferably, in the fuel injection control device for an internal combustion engine according to the present invention, the fuel injection timing control means divides the fuel supply from the first fuel injection means (in-cylinder injector) into two times, and the first fuel The first fuel supply from the injection means is performed in the first half of the intake stroke, and the second fuel supply is performed in the second half of the intake stroke or the compression stroke.

  Also preferably, in the fuel injection control device for an internal combustion engine according to the present invention, the fuel injection timing control means divides the fuel supply from the first fuel injection means into two times, and the first fuel injection means from the first fuel injection means The second fuel supply is performed in the latter half of the intake stroke, and the second fuel supply is performed in the compression stroke.

  According to the fuel injection control device for an internal combustion engine, the air flow formation in the fuel chamber is enhanced by a simple control method in which the fuel injection period from the first fuel injection means (in-cylinder injector) is divided into two. It is possible to improve the deterioration of combustion due to.

  More preferably, when the sharing ratio is set by the sharing ratio control means so that a part of the total fuel injection amount is injected from the first and second fuel injection means, respectively, the sharing ratio is maintained. As it is, the fuel supply from the first fuel injection means is divided into a plurality of times.

  According to the fuel injection control device for an internal combustion engine, it is possible to improve the deterioration of combustion by enhancing the formation of airflow in the fuel chamber without greatly changing the output characteristics from the internal combustion engine when the deterioration of combustion occurs.

  Alternatively, more preferably, in the fuel injection control device for an internal combustion engine according to the present invention, the control means further includes a share ratio correction means. The sharing ratio correction means is assigned when the fuel deterioration is continuously detected by the combustion deterioration detecting means even after the fuel supply from the first fuel injection means is divided into a plurality of times by the fuel injection timing control means. The sharing ratio is changed so that a part of the fuel injection amount from the second fuel injection means set by the ratio control means is replaced with the fuel injection amount from the first fuel injection means.

  Particularly in such a configuration, the fuel injection timing control means replaces the fuel injection amount replaced by the supply from the first fuel injection means by the sharing ratio correction means with a plurality of times of fuel supply from the first fuel injection means. It is preferable to inject at the time of fuel supply other than the first time.

  According to the fuel injection control device for an internal combustion engine, in the case where combustion deterioration continuously occurs even after the fuel supply from the first fuel injection means (in-cylinder injector) is divided into a plurality of times, The combustion injection share ratio from the first fuel injection means (in-cylinder injector) can be increased. As a result, even when continuous combustion deterioration occurs, improvement in combustion deterioration can be achieved by further strengthening airflow formation in the fuel chamber.

  A fuel injection control device for an internal combustion engine according to another configuration of the present invention includes a first fuel injection means, a second fuel injection means, and a control means. The control means includes a share ratio control means, a combustion deterioration detection means, and a share ratio correction means. The first fuel injection means injects fuel into the cylinder of the internal combustion engine. The second fuel injection means injects fuel into the intake passage of the internal combustion engine. The control means controls the fuel supply from the first fuel injection means and the second fuel injection means based on conditions required for the internal combustion engine. The sharing ratio control unit controls the sharing ratio of the fuel injection amount between the first fuel injection unit and the second fuel injection unit with respect to the total fuel injection amount based on conditions required for the internal combustion engine. The combustion deterioration detection means detects combustion deterioration in the internal combustion engine. The sharing ratio correction means sets the sharing ratio so that at least a part of the total fuel injection amount is injected from the second fuel injection means by the sharing ratio control means, and combustion deterioration is detected by the combustion deterioration detection means. In this case, the sharing ratio is changed so that a part of the fuel injection amount from the second fuel injection means set by the sharing ratio control means is replaced with the fuel injection amount from the first fuel injection means.

  According to the fuel injection control device for an internal combustion engine, the combustion injection share ratio from the first fuel injection means (in-cylinder injector) is increased when the occurrence of combustion deterioration in the internal combustion engine is detected. The amount of fuel sprayed directly on the fuel can be relatively increased. Therefore, it is possible to improve the combustion deterioration by increasing the combustion speed by strengthening the airflow in the cylinder.

  Preferably, in the fuel injection control device for an internal combustion engine according to another configuration of the present invention, the control means further includes fuel injection timing control means for controlling the fuel injection timing of the first fuel injection means. The fuel injection timing control means injects the fuel injection amount replaced by the supply from the first fuel injection means by the sharing ratio correction means at the latter stage of the intake stroke.

  According to the fuel injection control device for an internal combustion engine, an increase in the amount of fuel supplied from the first fuel injection means (in-cylinder injector) is injected in the latter half of the intake stroke. Therefore, since the time from fuel injection to ignition timing can be shortened within the range of the intake stroke, it is possible to improve the deterioration of combustion by enhancing the air flow formation in the fuel chamber within a range where the exhaust properties are not deteriorated.

  Preferably, in the fuel injection control device for an internal combustion engine according to another configuration of the present invention, the control means further includes a fuel injection timing control means for controlling the fuel injection timing of the first fuel injection means. The fuel injection timing control means injects the fuel injection amount replaced by the supply from the first fuel injection means by the sharing ratio correction means in the compression stroke.

  According to the fuel injection control device for an internal combustion engine, an increase in the amount of fuel supplied from the first fuel injection means (in-cylinder injector) is injected in the compression stroke. Therefore, since the time from fuel injection to ignition timing can be significantly shortened, airflow formation in the fuel chamber can be strengthened quickly to improve combustion deterioration.

  Alternatively, preferably, in the fuel injection control device for an internal combustion engine according to another configuration of the present invention, the share ratio correction unit continuously detects the combustion deterioration by the combustion deterioration detection unit even after the share ratio change by the share ratio correction unit. In this case, the fuel injection amount replaced with the supply from the first fuel injection means is increased according to the period in which the deterioration of combustion is continuously detected.

  According to the fuel injection control device for an internal combustion engine, when combustion deterioration continues, the first fuel injection means (in-cylinder injector) directly enters the cylinder according to the combustion deterioration continuation period. The amount of fuel sprayed can be gradually increased. Therefore, even when continuous combustion deterioration occurs, improvement of combustion deterioration can be achieved by further strengthening airflow formation in the fuel chamber.

  According to the fuel injection control apparatus for an internal combustion engine of the present invention, the first fuel injection means (in-cylinder injector) for injecting fuel into the cylinder and the second fuel for injecting fuel into the intake passage. In an internal combustion engine configured to include injection means (intake passage injection injector), by enhancing the air flow in the cylinder (combustion chamber) when combustion deterioration occurs, the combustion speed is increased to improve combustion deterioration. be able to.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following, the same or corresponding parts in the drawings are denoted by the same reference numerals, and detailed description thereof will not be repeated in principle.

  FIG. 1 shows a schematic configuration diagram of an engine system controlled by an engine ECU (Electronic Control Unit) which is a control device for an internal combustion engine according to an embodiment of the present invention. FIG. 1 shows an in-line four-cylinder gasoline engine as the engine, but the present invention is not limited to such an engine.

  As shown in FIG. 1, the engine (internal combustion engine) 10 includes four cylinders 112, and each cylinder 112 is connected to a common surge tank 30 via a corresponding intake manifold 20. The surge tank 30 is connected to an air cleaner 50 via an intake duct 40, an air flow meter 42 is disposed in the intake duct 40, and a throttle valve 70 driven by an electric motor 60 is disposed. The opening degree of throttle valve 70 is controlled based on the output signal of engine ECU 300 independently of accelerator pedal 100. On the other hand, each cylinder 112 is connected to a common exhaust manifold 80, and this exhaust manifold 80 is connected to a three-way catalytic converter 90.

  For each cylinder 112, an in-cylinder injector 110 for injecting fuel into the cylinder, and an intake passage injection injector 120 for injecting fuel into the intake port or / and the intake passage. And are provided respectively. These injectors 110 and 120 are controlled based on the output signal of engine ECU 300, respectively.

  FIG. 2 is a configuration diagram of an engine representatively showing one of the four cylinders 112 shown in FIG.

  Referring to FIG. 2, engine 10 includes a cylinder 111 having a cylinder block 101, a cylinder head 102 coupled to the upper portion of cylinder block 101, and a piston 103 that reciprocates within cylinder 111. Is done. The piston 103 is connected to a crankshaft 104 that is an output shaft of the engine 10 via a crank arm 105 and a connecting rod 106. The connecting rod 106 converts the reciprocating motion of the piston 103 into the rotation of the crankshaft 104. In the cylinder 111, a combustion chamber 107 for combusting the air-fuel mixture is defined by the inner wall of the cylinder block 101 and the cylinder head 102 and the top surface of the piston.

  The cylinder head 102 is provided with a spark plug 114 that ignites the air-fuel mixture in a manner protruding into the combustion chamber 107, and an in-cylinder injector 110 that injects and supplies fuel to the combustion chamber 107. Further, the intake passage injector 120 is arranged to inject and supply fuel to an intake manifold, that is, an intake port 22 or / and an intake passage 20 which is a communication portion between the intake passage 20 and the combustion chamber 107.

  The air-fuel mixture containing the fuel injected into the intake passage 20 and / or the intake port 22 is guided into the combustion chamber 107 during the valve opening period of the intake valve 24. The exhaust after the fuel is combusted by ignition by the spark plug 114 is sent to the three-way catalytic converter 90 (FIG. 1) via the exhaust passage (exhaust manifold) 80 during the valve opening period of the exhaust valve 84.

  In the present embodiment, an internal combustion engine in which two injectors are separately provided will be described. However, the present invention is not limited to such an internal combustion engine. For example, it may be an internal combustion engine having one injector that has both an in-cylinder injection function and an intake passage injection function.

  Referring again to FIG. 1, each in-cylinder injector 110 is connected to a common fuel distribution pipe 130. The fuel distribution pipe 130 is connected to an engine-driven high-pressure fuel pump 150 via a check valve 140 that can flow toward the fuel distribution pipe 130. The discharge side of the high-pressure fuel pump 150 is connected to the suction side of the high-pressure fuel pump 150 via an electromagnetic spill valve 152. The smaller the opening of the electromagnetic spill valve 152, the more the fuel distribution pipe 130 is connected to the high-pressure fuel pump 150. When the amount of fuel supplied to the inside is increased and the electromagnetic spill valve 152 is fully opened, the fuel supply from the high-pressure fuel pump 150 to the fuel distribution pipe 130 is stopped. Electromagnetic spill valve 152 is controlled based on the output signal of engine ECU 300.

  On the other hand, each intake passage injector 120 is connected to a common low-pressure fuel distribution pipe 160, and the fuel distribution pipe 160 and the high-pressure fuel pump 150 are connected to a common fuel pressure regulator 170 through an electric motor drive type. The low-pressure fuel pump 180 is connected. Further, the low pressure fuel pump 180 is connected to the fuel tank 200 via a fuel filter 190. The fuel pressure regulator 170 returns a part of the fuel discharged from the low-pressure fuel pump 180 to the fuel tank 200 when the fuel pressure of the fuel discharged from the low-pressure fuel pump 180 becomes higher than a predetermined set fuel pressure. It is configured. Therefore, the fuel pressure supplied to the intake manifold injector 120 and the fuel pressure supplied to the high-pressure fuel pump 150 are prevented from becoming higher than the set fuel pressure.

  The engine ECU 300 is composed of a digital computer, and is connected to each other via a bidirectional bus 310, a ROM (Read Only Memory) 320, a RAM (Random Access Memory) 330, a CPU (Central Processing Unit) 340, and an input port 350. And an output port 360.

  The air flow meter 42 generates an output voltage proportional to the amount of intake air, and the output voltage of the air flow meter 42 is input to the input port 350 via the A / D converter 370. A water temperature sensor 380 that generates an output voltage proportional to the engine cooling water temperature is attached to the engine 10, and the output voltage of the water temperature sensor 380 is input to the input port 350 via the A / D converter 390.

  A fuel pressure sensor 400 that generates an output voltage proportional to the fuel pressure in the fuel distribution pipe 130 is attached to the fuel distribution pipe 130, and the output voltage of the fuel pressure sensor 400 is input via the A / D converter 410. Input to port 350. The exhaust manifold 80 upstream of the three-way catalytic converter 90 is provided with an air-fuel ratio sensor 420 that generates an output voltage proportional to the oxygen concentration in the exhaust gas. The output voltage of the air-fuel ratio sensor 420 is converted into an A / D converter. It is input to the input port 350 via 430.

The air-fuel ratio sensor 420 in the engine system according to the present embodiment is a global air-fuel ratio sensor (linear air-fuel ratio sensor) that generates an output voltage proportional to the air-fuel ratio of the air-fuel mixture burned by the engine 10. The air-fuel ratio sensor 420 may be an O ₂ sensor that detects whether the air-fuel ratio of the air-fuel mixture burned in the engine 10 is rich or lean with respect to the stoichiometric air-fuel ratio. Good.

  The accelerator pedal 100 is connected to an accelerator opening sensor 440 that generates an output voltage proportional to the depression amount of the accelerator pedal 100, and the output voltage of the accelerator opening sensor 440 is input to the input port 350 via the A / D converter 450. Is input. The input port 350 is connected to a rotational speed sensor 460 that generates an output pulse representing the engine rotational speed. In the ROM 320 of the engine ECU 300, the value of the fuel injection amount and the engine cooling that are set according to the operating state based on the engine load factor and the engine speed obtained by the accelerator opening sensor 440 and the engine speed sensor 460 described above are stored. Correction values based on the water temperature and the like are previously mapped and stored.

  Engine ECU 300 generates various control signals for controlling the overall operation of the engine system based on signals from the sensors by executing a predetermined program. These control signals are sent to the equipment / circuit group constituting the engine system via the output port 360 and the drive circuit 470.

  In the engine system shown in FIG. 1, when two types of injectors having different characteristics are used depending on the rotation rate and load factor of the engine 10 as described below, the engine 10 is in a normal operation state. Homogeneous combustion is mainly performed.

  On the other hand, when the engine 10 is in an abnormal operation state such as when the catalyst is warmed up during idling, stratified combustion is performed.

  During the homogeneous combustion operation, the fuel injection amount sharing ratio between the in-cylinder injector 110 and the intake passage injector 120 with respect to the total fuel injection amount calculated as described above is controlled as described below. The

  3 and FIG. 4 are maps for setting the fuel injection amount sharing ratio (injection ratio) between the in-cylinder injector 110 and the intake manifold injector 120 during the homogeneous combustion operation in the engine system shown in FIG. It is a figure explaining the 1st example of.

  Referring to FIGS. 3 and 4, the injection ratio of in-cylinder injector 110 and intake manifold injector 120 (hereinafter also referred to as DI ratio r), which is information corresponding to the operating state of engine 10. .) Will be described. These maps are stored in the ROM 320 of the engine ECU 300. FIG. 3 is a warm map for the engine 10, and FIG. 4 is a cold map for the engine 10.

  As shown in FIG. 3 and FIG. 4, these maps show that the share ratio of the in-cylinder injector 110 is the DI ratio, with the rotational speed of the engine (internal combustion engine) 10 as the horizontal axis and the load factor as the vertical axis. It is shown as a percentage as r.

  As shown in FIGS. 3 and 4, the DI ratio r is set for each operation region determined by the rotation speed and load factor of the engine 10. “DI ratio r = 100%” means a region where fuel injection is performed only from in-cylinder injector 110, and “DI ratio r = 0%” means from intake manifold injector 120. This means that only the region where fuel injection is performed. “DI ratio r ≠ 0%”, “DI ratio r ≠ 100%” and “0% <DI ratio r <100%” indicate that in-cylinder injector 110 and intake passage injector 120 perform fuel injection. It means that the area is shared.

  In general, the in-cylinder injector 110 contributes to an increase in output performance, and the intake manifold injector 120 contributes to the uniformity of the air-fuel mixture. By using the two types of injectors having different characteristics depending on the rotational speed and load factor of the engine 10, homogeneous combustion is performed when the engine 10 is in a normal operation state.

  Further, as shown in FIG. 3 and FIG. 4, the DI share ratio r of the in-cylinder injector 110 and the intake manifold injector 120 is defined by dividing it into a warm map and a cold map. did. If the temperature of the engine 10 is different, the temperature of the engine 10 is detected by detecting the temperature of the engine 10 using a map set so that the control areas of the in-cylinder injector 110 and the intake manifold injector 120 are different. If it is equal to or higher than a predetermined temperature threshold value, the map for the warm time shown in FIG. 3 is selected. Otherwise, the map for the cold time shown in FIG. 4 is selected. Based on the selected maps, the in-cylinder injector 110 and / or the intake manifold injector 120 are controlled based on the rotation speed and load factor of the engine 10.

  The engine speed and load factor of engine 10 set in FIGS. 3 and 4 will be described. In FIG. 3, NE (1) is set to 2500 to 2700 rpm, KL (1) is set to 30 to 50%, and KL (2) is set to 60 to 90%. Further, NE (3) in FIG. 4 is set to 2900-3100 rpm. That is, NE (1) <NE (3). In addition, NE (2) in FIG. 3 and KL (3) and KL (4) in FIG. 4 are also set as appropriate.

  When FIG. 3 and FIG. 4 are compared, NE (3) of the map for cold shown in FIG. 4 is higher than NE (1) of the map for warm shown in FIG. This indicates that as the temperature of the engine 10 is lower, the control range of the intake manifold injector 120 is expanded to a higher engine speed range. That is, since the engine 10 is in a cold state, deposits are unlikely to accumulate at the injection port of the in-cylinder injector 110 (even if fuel is not injected from the in-cylinder injector 110). For this reason, it sets so that the area | region which injects a fuel using the intake manifold injector 120 may be expanded, and a homogeneity can be improved.

Comparing FIG. 3 and FIG. 4, in the region where the rotational speed of the engine 10 is NE (1) or higher in the warm map and in the region of NE (3) or higher in the cold map, “
DI ratio r = 100% ”. Further, the load factor is “DI ratio r = 100%” in the region of KL (2) or higher in the warm map and in the region of KL (4) or higher in the cold map. This indicates that only the in-cylinder injector 110 is used in a predetermined high engine speed region, and only the in-cylinder injector 110 is used in a predetermined high engine load region. . That is, in the high speed region and the high load region, even if the fuel is injected only by the in-cylinder injector 110, the engine 10 has a high rotational speed and load, and the intake amount is large. It is because it is easy to homogenize. Thus, the fuel injected from the in-cylinder injector 110 is vaporized with latent heat of vaporization (sucking heat from the combustion chamber) in the combustion chamber. Thereby, the temperature of the air-fuel mixture at the compression end is lowered. As a result, the knocking performance is improved. Further, since the temperature of the combustion chamber is lowered, the suction efficiency is improved and high output can be expected.

  In the warm map shown in FIG. 3, only the in-cylinder injector 110 is used at a load factor KL (1) or less. This indicates that when the temperature of the engine 10 is high, only the in-cylinder injector 110 is used in a predetermined low load region. Since the engine 10 is in a warm state during the warm period, deposits are likely to accumulate at the injection port of the in-cylinder injector 110. However, since the injection port temperature can be lowered by injecting fuel using the in-cylinder injector 110, it is conceivable to avoid deposit accumulation, and the minimum fuel injection amount of the in-cylinder injector It is also conceivable that the in-cylinder injector 110 is not blocked by ensuring the above. For this reason, in this region, fuel injection using the in-cylinder injector 110 is performed.

  Comparing FIG. 3 and FIG. 4, an area of “DI ratio r = 0%” exists only in the cold map of FIG. 4. This indicates that when the temperature of the engine 10 is low, only the intake manifold injector 120 is used in a predetermined low load region (KL (3) or less). This is because the engine 10 is cold and the load on the engine 10 is low and the intake air amount is low, so that the fuel is difficult to atomize. In such a region, it is difficult to perform good combustion with the fuel injection by the in-cylinder injector 110. In particular, a high output using the in-cylinder injector 110 is required in the region of low load and low rotation speed. Therefore, only the intake passage injector 120 is used without using the in-cylinder injector 110.

  In addition, in the case other than the normal operation, when the engine 10 is idling when the catalyst is warmed up (when the engine 10 is in a non-normal operation state), the in-cylinder injector 110 is controlled to perform stratified combustion. By causing stratified charge combustion only during such catalyst warm-up operation, catalyst warm-up is promoted and exhaust emission is improved.

  5 and 6 show a second example of the DI ratio r setting map in the engine system shown in FIG.

  The setting maps shown in FIG. 5 (when warm) and FIG. 6 (when cold) are compared with the setting maps shown in FIGS. 3 and 4 and the DI ratio in the high load region in the low engine speed region. The settings are different.

  In the engine 10, in the high load region of the low engine speed region, mixing of the air-fuel mixture formed by the fuel injected from the in-cylinder injector 110 is not good, and the air-fuel mixture in the combustion chamber is not homogeneous and combustion Has a tendency to become unstable. For this reason, the injection ratio of the in-cylinder injector is increased with the shift to the high rotation speed region where such a problem does not occur. In addition, the injection ratio of the in-cylinder injector 110 is decreased as the engine shifts to a high load region where such a problem occurs. These changes in the DI ratio r are indicated by cross arrows in FIGS.

  If it does in this way, the fluctuation | variation of the output torque of an engine resulting from combustion being unstable can be suppressed. It should be noted that these things can be achieved by reducing the injection ratio of the in-cylinder injector 110 as the engine shifts to the predetermined low rotational speed region, or by the in-cylinder injection as the vehicle shifts to the predetermined low load region. The fact that it is substantially equivalent to increasing the injection ratio of the injector 110 for operation will be described. Further, areas other than such areas (areas where the crossed arrows are described in FIGS. 5 and 6) and areas where fuel is injected only by the in-cylinder injector 110 (high rotation side, low load) On the other hand, it is easy to homogenize the air-fuel mixture with the in-cylinder injector 110 alone. Thus, the fuel injected from the in-cylinder injector 110 is vaporized with latent heat of vaporization (sucking heat from the combustion chamber) in the combustion chamber. Thereby, the temperature of the air-fuel mixture at the compression end is lowered. As a result, the knocking performance is improved. Further, since the temperature of the combustion chamber is lowered, the suction efficiency is improved and high output can be expected.

  In the engine 10 described with reference to FIGS. 3 to 6, the homogeneous combustion is basically based on the fuel injection timing of the in-cylinder injector 110, and the stratified combustion is performed in the in-cylinder injector. This can be realized by setting the fuel injection timing of 110 as the compression stroke. That is, by setting the fuel injection timing of the in-cylinder injector 110 as the compression stroke, stratified combustion is realized in which the rich air-fuel mixture is unevenly distributed around the spark plug and the entire combustion chamber ignites a lean air-fuel mixture. Can do. Further, even when the fuel injection timing of the in-cylinder injector 110 is set to the intake stroke, if rich air-fuel mixture can be unevenly distributed around the spark plug, stratified combustion can be realized even with the intake stroke injection.

  Further, the stratified combustion here includes both stratified combustion and weakly stratified combustion described below. In the weak stratified combustion, the intake passage injector 120 is injected with fuel in the intake stroke to produce a lean and homogeneous mixture in the entire combustion chamber, and the in-cylinder injector 110 is injected with fuel in the compression stroke. A rich air-fuel mixture is generated around the spark plug to improve the combustion state. Such weak stratified combustion is preferable when the catalyst is warmed up. This is due to the following reason. That is, it is necessary to significantly retard the ignition timing and maintain a good combustion state (idle state) in order to allow high-temperature combustion gas to reach the catalyst during catalyst warm-up. Moreover, it is necessary to supply a certain amount of fuel. Even if this is done by stratified combustion, there is a problem that the amount of fuel is small, and even if this is done by homogeneous combustion, there is a problem that the retard amount is small compared to stratified combustion in order to maintain good combustion. is there. From such a viewpoint, it is preferable to use the above-described weak stratified combustion at the time of warming up the catalyst, but either stratified combustion or weak stratified combustion may be used.

  As described below, according to the fuel injection control device for an internal combustion engine according to the embodiment of the present invention, the control for dividing the fuel injection timing from the in-cylinder injector 110 into a plurality of times when combustion deterioration is detected is mainly performed. To do. First, the fuel injection timing from each injector will be described with reference to FIG.

  The valve opening period 500 of the intake valve 24 and the valve opening period 510 of the exhaust valve 84 are set by valve timing control. Generally, the intake valve opening period 500 starts before top dead center (TDC) and ends after bottom dead center (BDC). Similarly, the exhaust valve opening period 510 starts prior to the bottom dead center (BDC) and ends after the top dead center (TDC). For this reason, an overlap period 515 in which both the intake valve 24 and the exhaust valve 84 are opened is provided across the top dead center (TDC).

  A fuel injection period (hereinafter also referred to as “PFI injection period”) 520 from the intake passage injector 120 is provided in the intake stroke in accordance with the intake valve opening period 500. Similarly, during the homogeneous combustion operation, a fuel injection period (hereinafter also referred to as “DI injection period”) 530 from in-cylinder injector 110 is basically provided in the intake stroke, particularly in the first half thereof.

  Since the fuel injection amount from in-cylinder injector 110 and intake passage injector 120 is proportional to the valve opening period of the injector, the lengths of the DI injection period and the PFI injection period are determined by each injector according to the DI ratio. It is determined according to the fuel injection amount to be shared.

  In the embodiment of the present invention, the intake stroke is classified into the intake stroke first half 550 and the intake stroke late 555 with the reference phase 540 as a boundary. The reference phase 540 is set to a crank angle phase of 135 ° after the top dead center (TDC) elapses, that is, ATDC 135 °, for example.

  The DI injection period is preferably provided in the intake stroke first half 550 for the homogenization of the air-fuel mixture in the combustion chamber 107, but in the case of the intake stroke late stage 555, the time from the fuel injection to the ignition timing is short. From this, the air flow can be strengthened by spraying, and the combustion speed can be increased.

  Furthermore, by providing the DI injection period in the compression stroke, the time from the fuel injection to the ignition timing can be further shortened, so that the combustion speed can be increased more significantly by strengthening the airflow. For example, the compression stroke injection period 560 is set to a section of about BTDC 45 ° to BTDC 135 °. On the other hand, at the time of fuel injection in the compression stroke injection period 560, exhaust properties tend to deteriorate due to an increase in unburned hydrocarbons (HC).

  In consideration of such characteristics with respect to the difference in fuel injection timing from in-cylinder injector 110, the fuel injection control device according to the embodiment of the present invention is shown in FIGS. 8 and 9 during the homogeneous combustion operation. Such fuel injection control is executed.

  In the fuel injection control according to the embodiment of the present invention, first, the basic DI ratio (basic DI ratio) according to the DI ratio map shown in FIGS. 3 to 6 according to the engine conditions (engine speed and load factor). r is set (step S100).

  Further, it is determined whether or not combustion deterioration has occurred in the engine (step S110). As a method for determining the occurrence of combustion deterioration, the time required for the crank to rotate a predetermined angle (90 degrees or 180 degrees) is sequentially detected, and the fluctuation in the required time for each cycle is monitored. There is a method to judge. In addition, by installing a combustion pressure sensor inside the combustion chamber 107, the pressure in the combustion chamber 107 is constantly measured, and the fluctuation in the combustion pressure between cycles is monitored to detect “occurrence of combustion deterioration”. You can also. Alternatively, it is possible to arrange an ion sensor for detecting ions generated at the time of combustion and detect “occurrence of combustion deterioration” based on monitoring of an ion generation amount between cycles. In addition, the combustion deterioration detection determination in step S110 is not limited to the above method, and any method that can be selectively employed by those skilled in the art can be applied.

  When the occurrence of combustion deterioration in the engine is not detected (NO determination in step S110), the combustion improvement control count value CNT for measuring the execution period of the combustion improvement control described later is cleared to the initial value (0). Then, the fuel injection control is ended (step S120). Therefore, fuel injection from in-cylinder injector 110 and intake manifold injector is executed in accordance with basic DI ratio r set in step S100. The DI injection period 530 in this case is basically set to the intake stroke first half 550. As described above, the length of the DI injection period 530, that is, the valve opening period length of the in-cylinder injector 110 is determined according to the fuel injection amount from the in-cylinder injector 110. In a region where the fuel injection amount from the injector 110 is large, there may be a case where the DI injection period 530 is shifted to the late stage 555 of the intake stroke.

  On the other hand, when occurrence of combustion deterioration in the engine is detected (YES determination in step S110), whether combustion deterioration has been detected for the first time this time, or combustion improvement control described below is being executed. Nevertheless, it is determined on the basis of the count value CNT whether the combustion deterioration is continuously occurring (step S130).

  First, control when combustion improvement control is not executed and combustion deterioration is detected this time, that is, when combustion deterioration newly occurs (NO determination in step S130) will be described.

  In this case, first, the basic DI ratio r set in step S100 is compared with a predetermined value R0 (%) to check whether or not a predetermined amount of in-cylinder fuel injection is ensured (step S140). Note that the determination in step S140 may be performed using the DI fuel injection amount Qdi indicated by the product of the total fuel injection amount Qttl and the basic DI ratio r, instead of the basic DI ratio r.

  If basic DI ratio r> R0 (YES determination in step S140), that is, if the predetermined amount of in-cylinder fuel injection is ensured, step group S150 is executed while maintaining basic DI ratio r. Thus, the DI injection period is divided into a plurality of times (in this embodiment, twice). Accordingly, the DI fuel injection amount Qdi from the in-cylinder injector 110 is divided into a fuel injection amount by the first DI injection and a fuel injection amount by the second DI injection according to a predetermined ratio ( Step S160).

  Further, according to the fuel injection amount by the first DI injection set in step S160, the valve closing timing of the first DI injection period is predicted, and whether or not this predicted valve closing timing is earlier than the reference phase 540. Determination is made (step S170).

  When the predicted valve closing timing is earlier than the reference phase 540, the second fuel injection can be executed at the late stage 555 of the intake stroke. On the other hand, when the predicted valve closing timing is later than the reference phase 540, the second fuel injection cannot be executed in the late stage 555 of the intake stroke.

  Comparing the fuel injection in the intake stroke late stage 555 and the compression stroke 560 as described above, the fuel injection in the compression stroke 560 has a greater combustion improvement effect, but there is a concern that the exhaust properties will deteriorate. Therefore, in the embodiment of the present invention, at the time of the first combustion improvement control, the second DI injection timing is provided as late as possible in the intake stroke 555 (step S180).

  Therefore, when the predicted valve closing timing in the first DI injection is earlier than the reference phase 540 (YES determination in step S170), as shown in FIG. 10, the DI injection period 530 is divided into two as shown in FIG. The second DI injection period 531 and the second DI injection period 532 are provided in the intake stroke first half 550 and the intake stroke late 555, respectively. Note that the total fuel injection amount in the first DI injection period 531 and the second DI injection period 532 is a DI injection amount Qdi.

  On the other hand, when the predicted closing timing in the first DI injection is later than the reference phase 540 (NO determination in step S170), the second DI injection period is provided in the compression stroke ( Step S190). Accordingly, as shown in FIG. 11, the first DI injection period 531 and the second DI injection period 532 obtained by dividing the DI injection period 530 into two are divided into the intake stroke first half 550 and the compression stroke 560 (typically Are provided at BTDC 45 degrees to 135 degrees, respectively. Also in this case, the total fuel injection amount in the first DI injection period 531 and the second DI injection period 532 is the DI fuel injection amount Qdi.

  As described above, when combustion deterioration occurs in the operation region in which the predetermined amount of in-cylinder fuel injection is ensured according to the basic DI ratio r set according to the engine conditions, the DI injection period is divided into a plurality of times, Combustion improvement control is performed by executing the second DI injection period in the latter half of the intake stroke or the compression stroke (step group S150). Thus, the deterioration of combustion can be improved by enhancing the air flow formation in the combustion chamber 107 and improving the combustion speed.

  In the step group S150 shown in FIG. 8, the second DI injection period 532 is selectively performed in either the intake stroke late stage 555 or the compression stroke 560 based on the determination in step S170. However, steps S170 and S180 may be omitted, and the second DI injection period 532 may be fixedly provided in the compression stroke 560. In this case, the DI injection period 532 is provided in the compression stroke 560 regardless of whether the first DI injection period 531 is performed in either the intake stroke first half 550 or the intake stroke late 555.

  Further, when the combustion improvement control by the step group S150 is performed, the combustion improvement control count value CNT is incremented (+1), and the fuel injection control is ended (step S230).

  On the other hand, at the time of NO determination in step S140 (r ≦ R0 (%), typically r≈0 (%)), that is, when the in-cylinder fuel injection amount is not secured according to the basic DI ratio r. In step S200, the DI ratio is corrected so that the in-cylinder fuel injection amount increases.

  That is, the predetermined correction amount Δr (Δr> 0) is increased with respect to the basic DI ratio r determined in step S100, and the DI ratio is corrected to r + Δr (step S210).

  Furthermore, the DI injection period corresponding to the increased DI ratio Δr is basically injected in the latter half of the intake stroke (step S220). If it is desired to positively improve the deterioration of combustion, a DI injection period corresponding to Δr may be provided in the compression stroke 560. If priority is given to preventing deterioration of exhaust properties, a DI injection period corresponding to Δr may be provided in the intake stroke first half 550.

  Thus, according to the basic DI ratio r, the DI ratio is corrected so that the in-cylinder fuel injection amount increases when combustion deterioration occurs in an operating region where the predetermined amount of in-cylinder fuel injection is not ensured. Thus, combustion improvement control is performed (step group S200). Also in this case, after the combustion improvement control count value CNT is incremented (+1) (step S230), the fuel injection control is terminated.

  When the combustion improvement control by dividing the DI injection period or correcting the DI ratio is executed in step S230, the combustion improvement control count value CNT is incremented and becomes larger than the initial value (0). In step S230, the actual DI ratio setting (r #) at the time of the current combustion improvement control is stored.

  Therefore, when the combustion improvement control count value CNT> 0 and the occurrence of combustion deterioration is detected in step S110, that is, when the combustion deterioration is continuously occurring despite the execution of the combustion improvement control. Step S130 is YES.

  In this case, the DI ratio setting (r #) in the previous combustion improvement control is compared with the current basic DI ratio r (step S100) (step S135). When the DI ratio r set under the present condition is the same level as or lower than the DI ratio setting r # in the previous combustion improvement control (when YES is determined in step S135), the fuel injection shown in FIG. A control flow is executed.

  In this case, the DI ratio correction amount Δr (> 0) is determined according to the combustion improvement control count value CNT (step S240), and the DI ratio correction amount Δr is determined as the basic DI ratio r determined in step S100. In addition, the DI ratio is corrected to r + Δr (step S250). The DI ratio correction amount Δr (Δr> 0) in step S240 is set to a larger value as the combustion improvement control count value CNT increases.

  Furthermore, the setting of the DI injection period 530 for injecting the DI fuel injection amount Qdi according to the DI ratio corrected in step S250 is executed, for example, in the same manner as in step group S150 (step S260). If the increase in DI fuel injection due to the correction amount Δr is set to be injected during the second DI injection period, the amount of injection in the latter half of the intake stroke or the compression stroke can be gradually increased. The improvement effect with respect to can be heightened.

  Alternatively, in step S260, as in step S220, the DI ratio correction amount Δr may be injected in the late intake stroke 555 or the compression stroke 560 without dividing the DI injection period 530. Also in this case, since the amount of injection in the latter stage of the intake stroke or the compression stroke can be gradually increased when the combustion deterioration continues, the improvement effect on the continuous combustion deterioration can be enhanced.

  Further, the combustion improvement control count value CNT is incremented (step S270), and the fuel injection control is terminated.

  Accordingly, when the occurrence of combustion deterioration is continuously detected, by setting at least a part of the DI injection period in the latter half of the intake stroke or the compression stroke while gradually increasing the DI ratio, Improvement of combustion deterioration is achieved by the effect of increasing the combustion speed by ensuring the formation of airflow.

Although a detailed control flow is not shown, when the selection conditions in steps S180 and S190 can be subdivided and the second DI injection period can be provided in the latter half of the intake stroke (when YES is determined in step S170) In addition, when the combustion improvement control count value CNT is large, the second DI injection period may be set to the compression stroke (step S190), and the combustion improvement may be performed with priority over the exhaust property. When the DI ratio is small and the combustion improvement control count value CNT is small, first, the combustion improvement control count is set while following the effect of the combustion improvement control by setting the DI injection period to the first half of the intake stroke. It is also possible to adopt a configuration that shifts to a region accompanied by deterioration of exhaust properties as the value CNT increases.

  On the other hand, when the determination in step S135 is NO, that is, when the DI ratio r set under the current condition is higher than the DI ratio setting r # in the previous combustion improvement control by a predetermined value or more, the combustion improvement control count value CNT is The initial value (0) is cleared (step S137), and step S140 and subsequent steps are executed in the same manner as the combustion improvement control count value CNT = 0.

  As described above, in the fuel injection control device for an internal combustion engine according to the embodiment of the present invention, the fuel from in-cylinder injector 110 is increased by increasing the DI ratio as necessary when detecting the occurrence of combustion deterioration in the engine. After securing the injection amount, at least a part of the fuel injection period from the in-cylinder injector 110, that is, the DI injection period, can be provided in the late stage of the intake stroke or the compression stroke. As a result, when combustion deterioration occurs due to a decrease in the combustion speed in the combustion chamber 107, in-cylinder fuel injection is performed at a timing closer to the ignition timing, thereby ensuring the formation of an air flow in the combustion chamber and reducing the combustion speed. It can be raised to improve the combustion state.

  In the combustion improvement control shown in FIGS. 8 and 9, the DI injection period is divided into two, but the DI injection period can be divided into a plurality of times of three or more. In particular, in step S180 of FIG. 8, the second and subsequent fuel injections may be further subdivided, and DI injection periods may be provided in both the late intake stroke and the compression stroke.

  The correspondence relationship between the engine system shown in FIG. 1 and the configuration of the present invention will be explained. The in-cylinder injector 110 corresponds to the “first fuel injection means” in the present invention, and the intake passage injector 120 is Corresponding to “second fuel injection means” in the present invention, engine ECU 300 corresponds to “control means” in the present invention.

  Further, the correspondence relationship between the flowcharts shown in FIGS. 8 and 9 for explaining the combustion improvement control executed by the engine ECU 300 and the configuration of the present invention will be described. Step S100 (FIG. 8) is a “sharing ratio control” in the present invention. Step S110 (FIG. 8) corresponds to “combustion deterioration detection means” in the present invention, and step group S150 (FIG. 8), S220 (FIG. 8) and step S260 (FIG. 9) correspond to this invention. Corresponds to “fuel injection timing control means”. Step S210 (FIG. 8) and step S250 (FIG. 9) correspond to the “sharing ratio correcting means” in the present invention.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a schematic configuration diagram of an engine system controlled by a control device for an internal combustion engine according to an embodiment of the present invention. It is a figure explaining the structure of the engine shown in FIG. FIG. 3 is a diagram for explaining a first example of a DI ratio setting map (when the engine is warm) during homogeneous combustion operation in the engine system shown in FIG. 1. FIG. 3 is a diagram for explaining a first example of a DI ratio setting map (when the engine is cold) during homogeneous combustion operation in the engine system shown in FIG. 1. It is a figure explaining the 2nd example of DI ratio setting map (at the time of engine warm) at the time of homogeneous combustion operation in the engine system shown in FIG. It is a figure explaining the 2nd example of DI ratio setting map (at the time of engine cold) at the time of homogeneous combustion operation in the engine system shown in FIG. It is a conceptual diagram explaining the fuel-injection time from each injector. It is a 1st flowchart explaining the fuel-injection control which concerns on embodiment of this invention. It is a 2nd flowchart explaining the fuel-injection control which concerns on embodiment of this invention. It is a conceptual diagram which shows the 1st example of DI injection period division | segmentation by the fuel injection control which concerns on embodiment of this invention. It is a conceptual diagram which shows the 2nd example of DI injection period division | segmentation by fuel injection control which concerns on embodiment of this invention.

Explanation of symbols

  10 engine, 20 intake manifold (intake passage), 22 intake port, 24 intake valve, 30 surge tank, 40 intake duct, 42 air flow meter, 50 air cleaner, 60 electric motor, 70 throttle valve, 80 exhaust manifold, 84 exhaust valve, 90 three-way catalytic converter, 100 accelerator pedal, 101 cylinder block, 102 cylinder head, 103 piston, 104 crankshaft, 105 crank arm, 106 connecting rod, 107 combustion chamber, 110 in-cylinder injector, 111 cylinder, 112 cylinder, 114 Spark plug, 120 Injector for intake passage injection, 130, 160 Fuel distribution pipe, 140 Check valve, 150 High pressure fuel pump, 152 Electromagnetic spill valve, 170 Fuel Regulator, 180 Low pressure fuel pump, 190 Fuel filter, 200 Fuel tank, 300 Engine ECU, 400 Fuel pressure sensor, 420 Air-fuel ratio sensor, 440 Accelerator opening sensor, 460 Rotational speed sensor, 500 Intake valve opening period, 510 Exhaust valve Valve opening period, 515 overlap period, 530 DI injection period, 531 DI injection period (first time when divided), 532 DI injection period (first time when divided), 540 Reference phase, 550 Intake stroke first half, 555 Intake stroke Late 560 compression stroke, CNT combustion improvement control count value, Qdi DI fuel injection amount, Qttl total fuel injection amount, r DI ratio (basic value), R0 predetermined value (DI ratio), Δr DI ratio correction amount.

Claims (10)

First fuel injection means for injecting fuel into the cylinder of the internal combustion engine;
Second fuel injection means for injecting fuel into the intake passage of the internal combustion engine;
Control means for controlling fuel supply from the first fuel injection means and the second fuel injection means based on conditions required for the internal combustion engine,
The control means includes
Sharing ratio control means for controlling the sharing ratio of the fuel injection amount between the first fuel injection means and the second fuel injection means with respect to the total fuel injection amount based on the conditions required for the internal combustion engine When,
Combustion deterioration detecting means for detecting combustion deterioration in the internal combustion engine;
The sharing ratio is set so that at least a part of the total fuel injection amount is injected from the first fuel injection means by the sharing ratio control means, and the combustion deterioration is detected by the combustion deterioration detection means. A fuel injection timing control means for controlling the fuel injection timing of the first fuel injection means so that the fuel supply from the first fuel injection means is divided into a plurality of times.
The fuel injection control device for an internal combustion engine, wherein the fuel injection timing control means sets at least a part of the supplied fuel divided into the plurality of times in at least one of an intake stroke late stage and a compression stroke. The fuel injection timing control means divides the fuel supply from the first fuel injection means into two times,
2. The internal combustion engine according to claim 1, wherein the first fuel supply from the first fuel injection means is performed in the first half of the intake stroke, and the second fuel supply is performed in the second half of the intake stroke or the compression stroke. Fuel injection control device. The fuel injection timing control means divides the fuel supply from the first fuel injection means into two times,
2. The fuel injection control device for an internal combustion engine according to claim 1, wherein the first fuel supply from the first fuel injection means is performed in a later stage of the intake stroke, and the second fuel supply is performed in a compression stroke. .   When the sharing ratio is set so that a part of the total fuel injection amount is injected from the first and second fuel injection means by the sharing ratio control means, the sharing ratio is maintained. The fuel injection control device for an internal combustion engine according to any one of claims 1 to 3, wherein the fuel supply from the first fuel injection means is divided into a plurality of times. The control means further includes
Even when the fuel supply from the first fuel injection means is divided into a plurality of times by the fuel injection timing control means, when the combustion deterioration is continuously detected by the combustion deterioration detection means, the sharing ratio A sharing ratio correction means for changing the sharing ratio so that a part of the fuel injection amount from the second fuel injection means set by the control means is replaced with the fuel injection amount from the first fuel injection means; The fuel injection control device for an internal combustion engine according to claim 4, further comprising:   The fuel injection timing control means replaces the fuel injection amount replaced by the supply from the first fuel injection means by the sharing ratio correction means with respect to a plurality of times of fuel supply from the first fuel injection means. The fuel injection control device for an internal combustion engine according to claim 5, wherein the fuel injection is performed at the time of fuel supply other than the first time. First fuel injection means for injecting fuel into the cylinder of the internal combustion engine;
Second fuel injection means for injecting fuel into the intake passage of the internal combustion engine;
Control means for controlling fuel supply from the first fuel injection means and the second fuel injection means based on conditions required for the internal combustion engine,
The control means includes
Sharing ratio control means for controlling the sharing ratio of the fuel injection amount between the first fuel injection means and the second fuel injection means with respect to the total fuel injection amount based on the conditions required for the internal combustion engine When,
Combustion deterioration detecting means for detecting combustion deterioration in the internal combustion engine;
The sharing ratio is set by the sharing ratio control means so that at least a part of the total fuel injection amount is injected from the second fuel injection means, and the combustion deterioration detection means detects the combustion deterioration. The share ratio is set so that a part of the fuel injection amount from the second fuel injection means set by the share ratio control means is replaced with the fuel injection amount from the first fuel injection means. A fuel injection control device for an internal combustion engine, comprising: a sharing ratio correction means for changing. The control means further includes a fuel injection timing control means for controlling a fuel injection timing of the first fuel injection means,
8. The fuel injection control of an internal combustion engine according to claim 7, wherein the fuel injection timing control means injects the fuel injection amount replaced by the supply from the first fuel injection means by the sharing ratio correction means in the late stage of the intake stroke. apparatus. The control means further includes a fuel injection timing control means for controlling a fuel injection timing of the first fuel injection means,
The fuel injection control device for an internal combustion engine according to claim 7, wherein the fuel injection timing control means injects the fuel injection amount replaced by the supply from the first fuel injection means by the sharing ratio correction means in a compression stroke. .   If the combustion deterioration is continuously detected by the combustion deterioration detecting means even after the sharing ratio is changed by the sharing ratio correcting means, the sharing ratio correcting means supplies the fuel from the first fuel injection means. The fuel injection control device for an internal combustion engine according to claim 7, wherein the fuel injection amount to be replaced with is increased according to a period during which the deterioration of combustion is continuously detected.

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