JP4337710B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention provides first fuel injection means (in-cylinder injector) for injecting fuel into the cylinder and second fuel injection means (intake passage injection) for injecting fuel into the intake passage or intake port. More specifically, the present invention relates to a fuel injection sharing ratio control between the two injectors in the engine warm-up process.

  In an internal combustion engine having an in-cylinder injector that directly injects fuel into the combustion chamber and an intake port injector that injects fuel into the intake port of each cylinder, the fuel is homogeneous only by fuel injection from the intake port injector. When combustion is performed, the in-cylinder injector is always exposed to high-temperature combustion gas, so that the tip of the in-cylinder injector is maintained at a high temperature, and deposits are likely to be deposited in the injection hole. For this reason, during the homogeneous combustion operation, in addition to opening the intake port injection injector to inject fuel into the intake port, the in-cylinder injector is also driven to open and inject fuel into the combustion chamber. There has been proposed a control method that suppresses the tip portion of the in-cylinder injector from being maintained at a high temperature (for example, Patent Document 1).

In such an internal combustion engine, it is difficult for deposits to accumulate in the injection hole portion of the in-cylinder injector, which leads to deterioration of combustion such as a change in the shape of the spray by the fuel injection injector and a decrease in the fuel injection amount. It is possible to avoid inconvenience and to stabilize the output characteristics of the internal combustion engine.
JP 2002-364409 A

  On the other hand, when the engine is cold, the atomization of fuel in the cylinder is difficult to promote, so the injected fuel is injected into the top surface (piston top surface) of the engine piston or the cylinder inner peripheral surface (cylinder inner peripheral surface (bore bore)). )) Tends to adhere in large quantities. For this reason, normally, when the engine is cold, the fuel injection timing is set during the intake stroke (intake stroke injection), and the period from fuel injection to ignition is secured as long as possible to promote atomization of the injected fuel. I am doing so. However, even if such an intake stroke injection is performed, it is difficult to completely eliminate the above-mentioned fuel adhesion, and some fuels are not used for combustion and remain attached even after engine combustion in the cylinder. It remains in the state.

  Of this adhering fuel, in particular, the adhering component on the piston top surface is gradually atomized at the time of subsequent engine combustion, incompletely combusted, and discharged from the cylinder. As a result, deterioration of exhaust properties such as generation of black smoke and increase of unburned components is caused.

  On the other hand, of the adhering fuel, the amount adhering to the inner circumferential surface of the cylinder is mixed with the lubricating oil adhering to the inner circumferential surface of the cylinder for lubricating the engine piston. As a result, dilution of the lubricating oil with the fuel, so-called fuel dilution occurs. Then, the lubricating oil in the cylinder diluted with the fuel is scraped off as the engine piston moves up and down, returned to the oil pan, and then used for lubricating the internal combustion engine. Therefore, if the fuel dilution of the lubricating oil frequently occurs, the ratio of the fuel mixed in the entire lubricating oil gradually increases, and eventually adversely affects the lubricating performance of the internal combustion engine.

  Therefore, in consideration of adverse effects such as deterioration of exhaust properties and reduction in lubrication performance of the internal combustion engine, in homogeneous combustion operation when the engine is cold, fuel injection is performed from the intake port injection injector as much as possible, and from the in-cylinder injection injector It is preferable to avoid fuel injection as much as possible.

  In this regard, Patent Document 1 counts the number of times that the in-cylinder injector is exposed to the flame caused by the combustion of the air-fuel mixture. Further, until this count value reaches a predetermined number of times that the temperature of the in-cylinder injector, which is obtained in advance by experiment, is not likely to reach the allowable temperature, fuel injection is performed only from the intake port injector. After the count value reaches a predetermined number of times, the fuel injection is controlled so that the fuel injection from the in-cylinder injector is also performed.

  However, the tip temperature of the in-cylinder injector rises due to the temperature of the entire internal combustion engine and the influence from the flame during the combustion of the air-fuel mixture. In particular, since the amount of heat transferred from the flame varies greatly depending on the operating conditions of the internal combustion engine, the fuel injection start timing from the in-cylinder injector is simply controlled based only on the number of air-fuel mixtures in the combustion chamber. In the configuration, even if the tip temperature of the in-cylinder injector rises above the allowable temperature, the fuel injection from the in-cylinder injector does not start, or the tip temperature of the in-cylinder injector does not reach the allowable temperature In this state, fuel injection from the in-cylinder injector may be performed, which may cause adverse effects such as deterioration of exhaust properties and deterioration of the lubrication performance of the internal combustion engine.

  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 the cylinder. Fuel injection from an in-cylinder injector when the engine is cold in an internal combustion engine provided with second fuel injection means (intake passage injection injector) for injecting fuel into the intake passage and / or the intake port It is to provide a control device that appropriately controls the fuel injection start timing from the in-cylinder injector so as to suppress deposit accumulation on the tip of the in-cylinder injector while suppressing the problem due to the above.

  An internal combustion engine control apparatus according to the present invention includes a first fuel injection unit (in-cylinder injector) for injecting fuel into a cylinder and a second fuel injection unit for injecting fuel into an intake passage. A control apparatus for an internal combustion engine including an (intake passage injection injector), which includes a temperature estimation unit, a first temperature determination unit, and a control unit. The temperature estimation means estimates the temperature of the first fuel injection means based on information including the operating state and temperature of the internal combustion engine. The first temperature determination unit determines whether the first fuel injection unit is in a high temperature state or a low temperature state by comparing the estimated temperature by the temperature estimation unit and the first reference temperature. The control means controls a 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 conditions required for the internal combustion engine. The control means includes a first fuel control injection means and a second fuel injection control means. When the first temperature determination means determines that the first fuel injection means is in a high temperature state, the control means The sharing ratio is set using the fuel injection control means 2. The first fuel control injection unit controls the sharing ratio so that the total fuel injection amount is injected from the second fuel injection unit. The second fuel injection control means controls the sharing ratio so that at least a part of the total fuel injection amount is injected from the first fuel injection means.

  In the control apparatus for an internal combustion engine, based on the estimated temperature of the first fuel injection means, fuel injection from the first fuel injection means is started when the estimated temperature rises. Thereby, since the fuel injection start timing from the first fuel injection means can be set appropriately, deposit accumulation at the tip of the in-cylinder injector can be more reliably suppressed. In other words, it is possible to prevent the occurrence of a problem that fuel injection from the in-cylinder injector is not started even if the tip temperature of the in-cylinder injector rises above the allowable temperature.

  Preferably, in the control apparatus for an internal combustion engine according to the present invention, the control means uses the first fuel injection control means when the first temperature determination means determines that the first fuel injection means is in a low temperature state. Set the ratio.

  In the control apparatus for an internal combustion engine, the fuel injection start timing from the first fuel injection means is appropriately set based on the estimated temperature of the first fuel injection means, and when the first fuel injection means is in a low temperature state. The total fuel injection amount is injected from the second fuel injection means. Therefore, it is possible to prevent the fuel from the first fuel injection means from being injected in a state in which the tip temperature of the in-cylinder injector does not reach the allowable temperature, and to perform exhaust by in-cylinder fuel injection when the engine is cold It is possible to suppress adverse effects such as deterioration of properties and deterioration of lubricating performance of the internal combustion engine.

  Preferably, in the control device for an internal combustion engine of the present invention, the internal combustion engine boosts the fuel to a predetermined pressure and supplies the fuel to the first fuel injection means, and supplies the fuel supplied from the high pressure fuel pump. A pressure measuring unit that measures pressure, and the control device further includes a pressure determining unit that determines whether or not the supplied fuel is within a predetermined pressure range based on a measurement value obtained by the pressure measuring unit. When it is determined that the first fuel injection means is in a high temperature state, the control means is based on the determination result of the pressure determination means, and when the supplied fuel is within a predetermined pressure range, the second fuel injection control means On the other hand, when the supplied fuel is not within the predetermined pressure range, the sharing ratio is set using the first fuel injection control means.

  In the control apparatus for an internal combustion engine, the fuel injection from the first fuel injection means is started on the condition that the fuel pressure is within a predetermined pressure range in which normal fuel injection from the first fuel injection means is possible. Is done. Therefore, it is possible to prevent the discontinuity of the output torque due to fluctuation of the total fuel injection amount in the internal combustion engine at the start of in-cylinder fuel injection.

  More preferably, the control device for an internal combustion engine of the present invention further includes second temperature determination means and pump operation control means. The second temperature determining means determines whether or not the estimated temperature by the temperature estimating means is equal to or higher than a second reference temperature set lower than the first reference temperature. The pump operation control unit operates the high-pressure fuel pump when the estimated temperature is equal to or higher than the second reference temperature based on the determination result of the second temperature determination unit, while the estimated temperature is lower than the second reference temperature. Stop high pressure fuel pump when low.

  In the control apparatus for an internal combustion engine, the high pressure fuel pump can be operated in advance prior to the start of fuel injection from the first fuel injection means based on the estimated temperature of the first fuel injection means. The fuel injection from one fuel injection means can be started smoothly. Further, when the temperature of the first fuel injection means once increased falls to a range where in-cylinder fuel injection is not performed, the high-pressure fuel pump can be stopped as appropriate, so that fuel efficiency can be improved.

  More preferably, in the control device for an internal combustion engine of the present invention, the first reference temperature is set to a different value depending on whether the first fuel injection means is currently in a high temperature state or a low temperature state. .

  In the control apparatus for an internal combustion engine, execution and stop of in-cylinder fuel injection by the first fuel injection unit are performed as the estimated temperature of the first fuel injection unit slightly fluctuates in the vicinity of the first reference temperature. It is possible to prevent frequent switching. As a result, occurrence of hunting can be prevented and fuel injection sharing control can be stabilized.

  Alternatively, more preferably, in the control device for an internal combustion engine of the present invention, the second reference temperature is set to a different value depending on whether the high-pressure fuel pump is currently operating or stopped.

  In the control apparatus for an internal combustion engine, it is possible to prevent the high-pressure fuel pump from repeatedly operating and stopping as the estimated temperature of the first fuel injection means fluctuates slightly near the second reference temperature. As a result, the occurrence of hunting can be prevented and the high-pressure pump drive control linked to the fuel injection sharing control can be stabilized.

  More preferably, in the control device for an internal combustion engine of the present invention, the second fuel injection control means controls the sharing ratio based on information including the temperature, the rotational speed, and the load factor of the internal combustion engine.

  In the control device for an internal combustion engine, the fuel injection amount sharing ratio between the first fuel injection means and the second fuel injection means is appropriately set in accordance with the operation state (temperature, rotation speed, and load factor) of the internal combustion engine. Can be set. Therefore, a stable internal combustion engine output can be obtained in the entire operation range.

  Preferably, in the control device for an internal combustion engine according to the present invention, the temperature estimation means includes a cooling water temperature of the internal combustion engine, a pipe temperature calculated from the outside air temperature, and an in-cylinder temperature estimated from the operating state of the internal combustion engine. Based on this, the temperature of the first fuel injection means is estimated.

  More preferably, in the control device for an internal combustion engine of the present invention, the temperature estimation means has means for estimating the in-cylinder temperature based on the load factor and the rotational speed of the internal combustion engine and the air-fuel ratio.

  In the control apparatus for an internal combustion engine, the temperature of the first fuel injection unit can be estimated more accurately reflecting the heat receiving state of the first fuel injection unit. Therefore, the fuel injection start timing from the first fuel injection means can be set more accurately. Therefore, the deposit accumulation preventing effect at the tip of the first fuel injection means (in-cylinder injector) according to the present invention, and the engine The effect of avoiding problems due to in-cylinder fuel injection during cold weather can be obtained more remarkably.

  According to the control apparatus for an internal combustion engine of the present invention, the fuel is injected toward the first fuel injection means (in-cylinder injector) for injecting the fuel into the cylinder and the intake passage and / or the intake port. In the internal combustion engine having the second fuel injection means (intake passage injector), deposit accumulation on the tip of the in-cylinder injector is suppressed while suppressing problems caused by in-cylinder fuel injection when the engine is cold. Can be more reliably suppressed.

  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. Although FIG. 1 shows an in-line four-cylinder gasoline engine as the engine, 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.

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

  As shown in 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 engine system 10 based on signals from the sensors by executing a predetermined program. These control signals are sent to a device / circuit group constituting the engine system 10 via the output port 360 and the drive circuit 470.

  In the engine 10 according to the embodiment of the present invention, each cylinder 112 is provided with both the in-cylinder injector 110 and the intake passage injector 120. Therefore, the necessary total fuel injection calculated as described above. Regarding the amount, it is necessary to perform fuel injection sharing control between the in-cylinder injector 110 and the intake passage injector 120.

  In the following, the fuel injection sharing ratio between the two injectors will be indicated by the DI ratio r, which is the ratio of the fuel injection amount from the in-cylinder injector 110 to the total fuel injection amount. That is, “DI ratio r = 100%” means that fuel injection is performed only from in-cylinder injector 110, and “DI ratio r = 0%” means only from intake manifold injector 120. It means that 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 to be 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.

  FIG. 2 is a diagram illustrating a basic concept of fuel injection sharing control by the control device according to the embodiment of the present invention.

  Referring to FIG. 2, in the fuel injection sharing control according to the embodiment of the present invention, according to the estimated temperature value Tinj of the tip portion of in-cylinder injector 110 (hereinafter simply referred to as “estimated tip temperature Tinj”). Thus, one of the first fuel injection control mode 500 and the second fuel injection control mode 510 is selected.

  As already described, when the engine is cold, it is preferable to perform fuel injection only by the intake passage injector 120 from the viewpoint of maintaining exhaust properties and lubrication performance. Therefore, when it is estimated from the estimated tip temperature Tinj that the in-cylinder injector 110 (especially the tip) is in a low temperature state, the total fuel injection amount is determined for the intake passage injection according to the first fuel injection control mode 500. Injected from the injector 120. That is, the DI ratio r = 0% is set.

  On the other hand, when the in-cylinder injector 110 is at a high temperature, there is a concern about deposit accumulation at the tip injection hole portion. Therefore, it is preferable to inject at least a part of the total fuel injection amount from the in-cylinder injector. . Therefore, when the in-cylinder injector 110 (particularly the tip) is estimated to be in a high temperature state from the estimated tip temperature Tinj, the DI ratio r> 0% is set according to the second fuel injection control mode 510. The

  In the second fuel injection control mode 510, the DI ratio is set by referring to a map created in advance according to the engine temperature and the engine operating state (rotation rate and load factor), and according to the set DI ratio. The fuel injection by both in-cylinder injector 110 and intake passage injector 120 or the fuel injection by in-cylinder injector 110 alone is performed. The setting of the DI ratio in the second fuel injection control mode 510 will be described in detail later.

  As will be described in detail below, the mode transition 520 from the first fuel injection control mode 500 to the second fuel injection control mode 510, and the second fuel injection control mode 510 to the first fuel injection control mode 500. The mode transition to 530 is executed based on a comparison between the estimated tip temperature Tinj and a predetermined reference temperature. Thus, in the embodiment of the present invention, since it is necessary to estimate the tip temperature of the in-cylinder injector 110, a method for calculating the tip estimated temperature Tinj will be described first.

  The tip temperature of in-cylinder injector 110 changes due to heat transfer from the entire engine connected to the injector and heat transfer from the in-cylinder (combustion chamber) temperature. The heat transfer from the entire engine can be estimated from the piping temperature calculated from the engine cooling water temperature and the outside air temperature. Further, the in-cylinder temperature can be estimated from the combustion state in the combustion chamber, that is, the engine operating conditions (rotation speed and load factor) and the air-fuel ratio (A / f). Therefore, the estimated tip temperature Tinj is calculated by a predetermined function having Ta, Tw, and Tcyl as variables, as shown in the following equation (1).

Tinj = f (Ta, Tw, Tcyl) (1)
Here, Ta represents the outside air temperature detected by an outside air temperature sensor (not shown), and Tw represents the cooling water temperature detected by the water temperature sensor 380. Tcyl is calculated by a predetermined function using the engine speed Erpm, the engine load factor Eld, and the set air-fuel ratio A / f as variables, as shown in the following equation (2).

Tcyl = f (Erpm, Eld, A / F) (2)
Note that the functions of the equations (1) and (2) are obtained by performing experiments in which the engine system 10 is operated under various conditions after attaching a temperature sensor to the in-cylinder injector 110 (particularly the tip portion). This can be determined by reflecting this experimental result. Further, in order to more accurately reflect the heat transfer phenomenon to the in-cylinder injector 110, temperature estimation may be performed instead of the above equations (1) and (2) using other variables.

  Next, an operation example of fuel injection sharing control by the control device according to the embodiment of the present invention will be described with reference to FIG.

  Referring to FIG. 3, the injection prohibition flag xihd is a flag indicating selection of the first fuel injection control mode 500 and the second fuel injection control mode 510 shown in FIG. 2. When xihd = “on”, the first fuel injection control mode 500 shown in FIG. 2 is selected and the DI ratio r = 0% is set. That is, the necessary total fuel injection amount is injected from the intake manifold injector 120. On the other hand, when xihd = “off”, the second fuel injection control mode 510 shown in FIG. 2 is selected and the DI ratio r> 0% is set. That is, at least a part of the necessary total fuel injection amount is injected from the in-cylinder injector 110.

  Basically, the injection division prohibition flag xihd depends on whether the in-cylinder injector 110 is in a low temperature state or a high temperature state based on a comparison between the estimated tip temperature Tinj and the reference temperatures Tr1 and Tr1 #. Is set. That is, xihd = “on” is set when the in-cylinder injector 110 is in a low temperature state, and xihd = “off” is set when the in-cylinder injector 110 is in a high temperature state.

  Operation and stop of the high-pressure fuel pump 150 (FIG. 1) for boosting the fuel injected from the in-cylinder injector 110 to a predetermined pressure prf is controlled by the fuel pump drive flag xpmp. Specifically, the high pressure fuel pump 150 is operated when xpmp = “on”, while the high pressure fuel pump 150 is stopped when xpmp = “off”. The fuel pump drive flag xpmp is set based on a comparison between the estimated tip temperature Tinj and the reference temperatures Tr2 and Tr2 #.

  When the engine is started, the injection division prohibition flag xihd is set to “on” corresponding to the low temperature state of the in-cylinder injector 110 as an initial value. Further, since the estimated tip temperature Tinj is lower than the reference temperature Tr2, the fuel pump drive flag xpmp is initially set to “off”. Thus, the total fuel injection amount is injected from the intake manifold injector 120, and the high-pressure fuel pump 150 is stopped. In this state, the pressure of the fuel supplied from the high-pressure fuel pump 150 to the in-cylinder injector 110 (hereinafter simply referred to as “fuel pressure”) remains low.

  As the engine is operated by fuel injection by the intake manifold injector 120, the estimated tip temperature Tinj starts to rise and reaches the reference temperature Tr2 at time t1. As a result, the fuel pump drive flag xpmp changes from “off” to “on”, so that the high-pressure fuel pump 150 starts operation and the fuel pressure fpr begins to rise.

  The estimated tip temperature Tinj continues to rise with the operation of the engine and reaches the reference temperature Tr1 at time t2. Since the reference temperature Tr1 corresponds to the boundary value between the low temperature state and the high temperature state of the in-cylinder injector 110, the in-cylinder injector 110 transitions from the low temperature state to the high temperature state at time t2. That is, it is preferable to inject at least a part of the total fuel injection amount from the in-cylinder injector in order to suppress the deposit accumulation in the injection hole at the front end as the tip temperature of the in-cylinder injector 110 rises. It is shown that the condition has been reached.

  When in-cylinder injector 110 is in a high temperature state, it is further determined whether or not the fuel pressure is within a pressure range in which normal fuel injection from in-cylinder injector 110 is possible. Specifically, it is determined whether or not the difference | fpr−prf | between the fuel pressure fpr and the predetermined pressure prf is equal to or smaller than a predetermined value pb. Although the predetermined pressure prf is a constant value in FIG. 3, the predetermined pressure prf may be changed according to the fuel injection conditions required for the in-cylinder injector 110.

  When the in-cylinder injector 110 is in a high temperature state and the fuel pressure has increased to a predetermined level, the injection separation prohibition flag xihd is changed from “on” to “off”. As a result, the mode transition 520 in FIG. 1 is executed, the fuel injection sharing control transitions from the first control injection control mode 500 to the second control injection control mode 510, and at least a part of the total fuel injection amount is a cylinder. The DI ratio r is set so as to be injected from the inner injection injector 110 (that is, r> 0%).

  As a result, fuel injection from the in-cylinder injector 110 whose tip temperature has increased is started, and deposit accumulation on the in-cylinder injector 110 can be suppressed. Further, since the fuel pressure is checked at the start of fuel injection from the in-cylinder injector 110, it is avoided that the total fuel injection amount in the engine fluctuates and the output torque becomes discontinuous at this time. it can.

  As shown in FIG. 3, the reference temperature Tr2 used for operation control of the high-pressure fuel pump 150 is set lower than the reference temperature Tr1 used for fuel injection sharing control (Tr2 = Tr1-ΔTp). Thus, the operation of the high-pressure fuel pump 150 can be started in advance until the estimated tip temperature Tinj reaches the reference temperature Tr1. As a result, it is possible to smoothly shift from the state where only the intake manifold injector 120 is used to the combined use state of the in-cylinder injector 110 and the intake manifold injector 120.

  Further, during the period until the tip temperature of in-cylinder injector 110 rises (before time t2 in FIG. 3), the entire fuel injection amount is injected from intake manifold injector 120, and in-cylinder injector 110 is Since it is not used, it is possible to avoid adverse effects such as deterioration of exhaust properties and deterioration of lubricating performance of the internal combustion engine due to in-cylinder fuel injection when the engine is cold.

  In the fuel injection sharing control by the control device according to the embodiment of the present invention, even after the transition to the combined use state of the in-cylinder injector 110 and the intake passage injector 120 (second fuel injection control mode 510), When the tip temperature of the in-cylinder injector 110 is lowered, it is possible to make a transition to a state in which only the intake manifold injector 120 is used (first fuel injection control mode 500).

  As shown in FIG. 3, tip estimated temperature Tinj decreases after time t2, and becomes lower than reference temperature Tr1 # at time t3. Since reference temperature Tr1 # corresponds to the boundary value between the low temperature state and high temperature state of in-cylinder injector 110, in-cylinder injector 110 transitions from the high temperature state to the low temperature state at time t3. That is, it is shown that the tip temperature of the in-cylinder injector 110 is lowered, and the risk of deposit accumulation at the tip nozzle hole portion is reduced. In this state, since the temperature in the combustion chamber is also lowered, the possibility of adverse effects such as deterioration of exhaust properties and deterioration of the lubricating performance of the internal combustion engine can be avoided by performing in-cylinder fuel injection. Indicated.

  Accordingly, in response to the transition of the in-cylinder injector 110 to the low temperature state, the injection prohibition flag xihd changes from “off” to “on” again. In response to this, the mode transition 530 in FIG. 1 is executed, and the fuel injection sharing control transitions from the second control injection control mode 510 to the first control injection control mode 510. As a result, fuel injection from the in-cylinder injector 110 is prohibited, and the DI ratio r is set so that the entire fuel injection amount is injected from the intake manifold injector 120 (ie, r = 0%). As a result, even when the engine temperature and the temperature of the in-cylinder injector 110 are lowered again, the in-cylinder fuel injection is performed when the engine is cold by supplying the total fuel injection amount from the intake manifold injector 120. It is possible to prevent the adverse effects caused by.

  Further, the temperature of the in-cylinder injector 110 (particularly, the tip portion) decreases, and the estimated tip temperature Tinj is set to a reference temperature Tr2 # (Tr2 # = Tr1) set lower than the reference temperature Tr1 # at time t4. # −ΔTp #). In response to this, the high-pressure fuel pump 150 is stopped by changing the fuel pump drive flag xpmp from “on” to “off”.

  Therefore, when the tip temperature of the in-cylinder injector is sufficiently lowered, the fuel injection from the in-cylinder injector 110 is prohibited, and the operation of the high-pressure fuel pump 150 is stopped, thereby reducing the fuel consumption. Improvements can be made.

  As shown in FIG. 4, the reference temperature Tr1 # for determining the transition from the high temperature state to the low temperature state (corresponding to the mode transition 530) of the in-cylinder injector 110, and the transition from the low temperature state to the high temperature state ( It is set to a different value from the reference temperature Tr1 for determining (corresponding to mode transition 520). As described above, by providing hysteresis (ΔT1 in FIG. 3) to the reference temperature between the mode transitions 520 and 530, the transition between the fuel injection control modes 500 and 510 frequently occurs, so-called hunting phenomenon occurs. Can be prevented.

  Similarly, as shown in FIG. 5, both the reference temperature Tr2 # for determining the transition from the operating state to the stopped state of the high-pressure fuel pump 150 and the reference temperature Tr2 for determining the transition from the stopped state to the operating state. By providing the hysteresis (ΔT2 in FIG. 3), it is possible to prevent the hunting phenomenon that the high-pressure fuel pump 150 frequently repeats between the stop state and the operation state in a short time.

  When the estimated tip temperature Tinj rises again after time t4, the same determination as that at times t1 and t2 is executed using the reference temperatures Tr1 and Tr # 1, and the temperature of the in-cylinder injector 110 is increased. When the fuel pressure rises again, the fuel injection from the in-cylinder injector 110 is started again after confirming the increase in fuel pressure by the high-pressure fuel pump 150.

  Next, the flowchart of the fuel injection sharing control described in FIG. 3 will be described with reference to FIGS. 6 and 7.

  Referring to FIG. 6, when the fuel injection sharing control is started, it is first determined whether or not the engine is at the start (step S100), and if it is at the start (Y determination in step S100), the injection is divided. The prohibition flag xihd is initially set to “ON” (step S110). On the other hand, when it is not at the time of starting (N determination in step S100), the current value of the injection prohibition flag xihd is maintained.

  Next, the tip temperature of the in-cylinder injector 110 (DI injector) is estimated according to the above equations (1) and (2), and the tip estimated temperature Tinj is calculated (step S120).

  Next, it is determined whether the injection prohibition flag xihd is “ON” (step S130). If xihd = “ON” (Y determination in step S130), the high-pressure fuel pump drive in steps S140 to S170 is performed. Control is executed.

  First, it is determined whether the estimated tip temperature Tinj is equal to or higher than the reference temperature Tr2 (step S140). If Tinj ≧ Tr2 (Y determination in step S140), the fuel pump drive flag xpmp is set to “on”. (Step S160).

  On the other hand, if Tinj <Tr2 (N determination in step S140), it is further determined whether Tinj is lower than Tr2 # (step S150). As shown in FIG. 3, the reference temperature Tr2 # is set lower than the reference temperature Tr2 by providing a hysteresis ΔT2.

  If the determination in step S150 is N, that is, if Tr2 # ≦ Tinj <Tr2, the fuel pump drive flag xpmp is set to “on”. On the other hand, if the determination in step S150 is Y, that is, if Tinj <Tr2 # (<Tr2), the fuel pump drive flag xpmp is set to “off” in order to stop the operation of the high-pressure fuel pump 150 (step S150). S170).

  When xihd = “off” (N determination in step S130), the fuel pump drive flag xpmp has been set to “on” before that and the high-pressure fuel pump 150 needs to be operated. Therefore, the high-pressure fuel pump drive control in steps S140 to S170 is not executed, and the fuel pump drive flag xpmp = “on” is maintained.

  Next, steps S180 to S230 are performed in which transition between the first fuel injection control state 500 and the second fuel injection control mode 510 is determined using the reference temperatures Tr1 and Tr1 #.

  In step S180, it is determined whether the tip estimated temperature Tinj is equal to or higher than the reference temperature Tr1. If Tinj ≧ Tr1 (Y determination in step S180), it is further determined whether or not the fuel pressure has reached the pressure (predetermined pressure prf) at which normal fuel injection from the in-cylinder injector 110 is possible (predetermined pressure prf). Step S190). Specifically, if the difference between the fuel pressure fpr detected by the fuel pressure sensor 400 and the predetermined pressure prf is within the predetermined range pb, that is, | fpr−prf | ≦ pb (Y in step S190) In the determination), since the in-cylinder injector 110 is in a high temperature state and the fuel pressure is also increased, the injection prohibition flag xihd is set in order to start fuel injection from the in-cylinder injector 110. “Off” is set (step S210).

  On the other hand, if | fpr−prf |> pb (N determination in step S190), the in-cylinder injector 110 is in a high temperature state, but the normal in-cylinder fuel pressure is insufficient. Since fuel injection cannot be performed, the injection prohibition flag xihd is maintained at the current value, that is, “ON” (step S220).

  On the other hand, if Tinj <Tr1 (N determination in step 180), it is further determined whether Tinj is lower than Tr1 # (step S200). As shown in FIG. 3, the hysteresis ΔT1 is provided and Tr1 # <Tr1 is set.

  If the determination in step S200 is Y, that is, Tinj <Tr1 #, the mode transition 530 shown in FIG. 2 is performed, and therefore the injection prohibition flag xihd is set to “on” (step S230). On the other hand, if Tinj ≧ Tr1 # (N determination in step S200), the condition for mode transition 530 is not permitted, so that the injection prohibition flag xihd is maintained at the current value, that is, “off” (step S220).

  The mode transitions 520 and 530 between the fuel injection control modes 500 and 510 as shown in FIG. 2 are realized by the setting control of the injection division prohibition flag xihd as described above. When the injection division prohibition flag xihd = “on” (Y determination in step S240), fuel injection from the in-cylinder injector 110 is prohibited in accordance with the first fuel injection control mode 500 shown in FIG. Thus, the total fuel injection amount is injected from the intake manifold injector 120, and the port injection (PFI) becomes 100%. That is, the DI ratio r = 0% is set (step S250).

  On the other hand, when the injection restriction flag xihd = “off” (N determination in step S240), the map in engine ECU 300 is referred to in accordance with second fuel injection control mode 510 shown in FIG. The DI ratio r corresponding to the temperature, the rotation speed, and the load factor is selected (step S260). In accordance with the DI ratio obtained in step S260, fuel injection is performed between the in-cylinder injector (DI injector) and the intake manifold injector (PFI injector) (step S270).

  As described above, the program for executing the flowcharts shown in FIGS. 6 and 7 is stored in engine ECU 300, so that the fuel injection sharing control as shown in FIG. 5 can be executed in response to the activation of the program. It is.

  Here, the correspondence between the configuration of the engine system according to the embodiment of the present invention and the configuration of the present invention will be described. The in-cylinder injector 110 corresponds to the “first fuel injection means” in the present invention. The intake passage injector 120 corresponds to the “second fuel injection unit” in the present invention, and the high pressure fuel pump 150 and the fuel pressure sensor 400 correspond to the “high pressure fuel pump” and the “pressure measurement unit” in the present invention, respectively. Correspond.

  Further, the correspondence between the flowcharts shown in FIGS. 6 and 7 and the configuration of the present invention will be described. The temperature determination in step S180 corresponds to the “first temperature determination means” in the present invention, and the process in step S140. The temperature determination corresponds to the “second temperature determination means” in the present invention, the fuel pressure determination in step S190 corresponds to the “pressure determination means” in the present invention, and the fuel pump drive flag control in steps S160 and S170 is This corresponds to “pump operation control means” in the invention. Step S250 for performing fuel injection in first fuel injection control mode 500 corresponds to “first fuel injection control means” in the present invention, and step S270 for performing fuel injection in second fuel injection control mode 510. Corresponds to the “second fuel injection control means” in the present invention.

  As described above, in the control device for an internal combustion engine according to the embodiment of the present invention, based on the estimated tip temperature of in-cylinder injector 110, fuel injection from in-cylinder injector 110 is started when the tip temperature rises. To do. As a result, the start timing of in-cylinder injection can be set appropriately, so that deposit accumulation on the tip of the in-cylinder injector can be prevented while suppressing problems caused by fuel injection from the in-cylinder injector when the engine is cold. It can suppress more reliably. That is, even if the tip temperature of the in-cylinder injector rises above the allowable temperature, the fuel injection from the in-cylinder injector does not start, or the tip temperature of the in-cylinder injector does not reach the allowable temperature Thus, fuel injection from the in-cylinder injector is executed, and adverse effects such as deterioration of exhaust properties and deterioration of lubricating performance of the internal combustion engine can be suppressed.

  Further, since the fuel pressure is checked at the start of fuel injection from the in-cylinder injector 110, the total fuel injection amount in the engine fluctuates when the fuel injection control mode is switched, and output torque discontinuity occurs. You can avoid that.

  Next, a preferable setting of the DI ratio in the second fuel injection control mode 510, that is, step S260 will be described.

  8 and 9 are diagrams illustrating a first example of a DI ratio setting map in the engine system shown in FIG.

  The maps shown in FIGS. 8 and 9 are stored in ROM 320 of engine ECU 300. FIG. 8 is a warm map of the engine 10, and FIG. 9 is a cold map of the engine 10.

  As shown in FIG. 8 and FIG. 9, these maps are shown in percentages where the engine 10 rotational speed is on the horizontal axis, the load factor is on the vertical axis, and the share ratio of the in-cylinder injector 110 is the DI ratio r. It is shown.

  As shown in FIGS. 8 and 9, the DI ratio r is defined for each operation region that is determined by the engine speed and the load factor in a warm map and a cold map. 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, the map at the time of warm in FIG. 8 is selected, and if not, the map at the time of cold shown in FIG. 9 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. 8 and 9 will be described. In FIG. 8, 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. 9 is set to 2900-3100 rpm. That is, NE (1) <NE (3). In addition, NE (2) in FIG. 8 and KL (3) and KL (4) in FIG. 9 are also set as appropriate.

  Comparing FIG. 8 and FIG. 9, NE (3) of the cold map shown in FIG. 9 is higher than NE (1) of the warm map 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.

8 and FIG. 9, in the region where the rotational speed of the engine 10 is NE (1) or more in the warm map and in the region where NE (3) or more 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. 8, 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. 8 and FIG. 9, there is an area of “DI ratio r = 0%” only in the cold map of FIG. 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, the in-cylinder injector 110 is controlled so as to perform stratified combustion when the engine 10 is at the time of catalyst warm-up when idling (in a non-normal operation state). By performing stratified charge combustion only during such catalyst warm-up operation, catalyst warm-up is promoted and exhaust emission is improved.

  10 and 11 show a second example of the DI ratio setting map in the engine system shown in FIG.

  The setting maps shown in FIG. 10 (during warm) and FIG. 11 (during cold) are compared with the setting maps shown in FIG. 8 and FIG. 9 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 inhomogeneous and combustion occurs. 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. 10 and 11) 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 addition, since the DI ratio setting in other regions in the setting maps shown in FIGS. 10 and 11 is the same as that in FIG. 8 (warm) and FIG. 9 (cold), detailed description will be repeated. Absent.

  In the maps of FIGS. 9 and 11 (during cold), there is a region where the DI ratio r = 0% (PFI region). Therefore, in the second fuel injection control mode 510 as well, There is a possibility that the fuel injection amount is injected from the intake manifold injector 120. However, as already described, the tip temperature of in-cylinder injector 110 rises due to heat transfer from the entire engine and heat transfer from the in-cylinder (combustion chamber) temperature. Therefore, when the estimated tip temperature Tinj rises, the engine coolant temperature and / or the engine speed / load factor rises, so that the transition to the warm map (FIGS. 8 and 10) where the PFI region does not exist, or The DI ratio is set outside the PFI area on the cold map (FIGS. 9 and 11). Therefore, in the embodiment of the present invention, at the time of fuel injection control in the second combustion injection control mode, substantially at least a part of the fuel injection amount is injected from the in-cylinder injector 110.

  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 according to an embodiment of the present invention. It is a conceptual diagram explaining the fuel injection sharing control by the control apparatus which concerns on embodiment of this invention. It is a wave form diagram which shows the operation example of the fuel injection sharing control by the control apparatus which concerns on embodiment of this invention. It is a figure explaining the hysteresis setting in determination regarding fuel injection control. It is a figure explaining the hysteresis setting in determination regarding the operation control of a high pressure fuel pump. It is a 1st flowchart explaining the fuel injection sharing control by the control apparatus which concerns on embodiment of this invention. It is a 2nd flowchart explaining fuel injection sharing control by the control apparatus which concerns on embodiment of this invention. It is a figure explaining the 1st example of DI ratio setting map (at the time of engine warm) in the engine system shown in FIG. It is a figure explaining the 1st example of DI ratio setting map (at the time of engine cold) 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 warm) 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) in the engine system shown in FIG.

Explanation of symbols

10 engine, 20 intake manifold, 30 surge tank, 40 intake duct, 50 air cleaner, 60 electric motor, 70 throttle valve, 80 exhaust manifold, 90 three-way catalytic converter, 100 accelerator pedal, 110 in-cylinder injector, 112 cylinder, 120 Intake passage injector, 130 Fuel distribution pipe, 140 Check valve, 150 High pressure fuel pump, 152 Electromagnetic spill valve, 160
Fuel distribution pipe, 170 Fuel pressure regulator, 180 Low pressure fuel pump, 190 Fuel filter, 200 Fuel tank, 300 Engine ECU, 380 Water temperature sensor, 400 Fuel pressure sensor, 420 Air fuel ratio sensor, 440 Accelerator opening sensor, 460 Rotational speed sensor , 500, 510 Fuel injection control mode, 520, 530 Mode transition (between fuel injection control states), fpr fuel pressure, r DI ratio, Tinj estimated tip temperature (in-cylinder injector), Tr1, Tr1 # reference temperature (fuel Injection sharing control), Tr2, Tr2 # reference temperature (high-pressure fuel pump drive control), xihd injection prohibition flag, xpmp fuel pump drive flag, ΔT1, ΔT2 hysteresis (reference temperature).

Claims (6)

A first fuel injection means for injecting fuel into the cylinder; a second fuel injection means for injecting fuel into the intake passage; and the first fuel injection means by boosting the fuel to a predetermined pressure. A control device for an internal combustion engine, comprising: a high-pressure fuel pump for supplying to the fuel; and a pressure measuring unit for measuring a pressure of fuel supplied from the high-pressure fuel pump,
Temperature estimating means for estimating the temperature of the first fuel injection means based on information including the operating state and temperature of the internal combustion engine;
First temperature determination means for determining whether the first fuel injection means is in a high temperature state or a low temperature state by comparing the estimated temperature by the temperature estimation means with a first reference temperature;
Pressure determining means for determining whether or not the supplied fuel is within a predetermined pressure range based on a measurement value in the pressure measuring unit;
Second temperature determination means for determining whether the estimated temperature by the temperature estimation means is equal to or higher than a second reference temperature set lower than the first reference temperature;
Based on the determination result of the second temperature determination means, the high-pressure fuel pump is operated when the estimated temperature is equal to or higher than the second reference temperature, while the estimated temperature is higher than the second reference temperature. Pump operation control means for stopping the high-pressure fuel pump when low,
Control means for controlling a share 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 conditions required for the internal combustion engine; Prepared,
The control means includes
First fuel control injection means for controlling the sharing ratio so that the total fuel injection amount is injected from the second fuel injection means;
Second fuel injection control means for controlling the sharing ratio so that at least a part of the total fuel injection amount is injected from the first fuel injection means;
When the first temperature determination unit determines that the first fuel injection unit is in the high temperature state, the control unit determines that the supplied fuel is based on the determination result of the pressure determination unit. When it is within the range, the share ratio is set using the second fuel injection control means, while when the supply fuel is not within the predetermined pressure range, the share is established using the first fuel injection control means. Set the ratio , and
An internal combustion engine configured to set the sharing ratio using the first fuel injection control unit when the first temperature determination unit determines that the first fuel injection unit is in the low temperature state; Engine control device. 2. The control device for an internal combustion engine according to claim 1, wherein the first reference temperature is set to a different value according to whether the first fuel injection unit is currently in the high temperature state or the low temperature state. .   The control apparatus for an internal combustion engine according to claim 1, wherein the second reference temperature is set to a different value according to whether the high-pressure fuel pump is currently operating or stopped. The internal combustion engine according to any one of claims 1 to 3 , wherein the second fuel injection control means controls the sharing ratio based on information including a temperature, a rotation number, and a load factor of the internal combustion engine. Control device. The temperature estimating means is the first fuel injection means based on the coolant temperature of the internal combustion engine, the pipe temperature calculated from the outside air temperature, and the in-cylinder temperature estimated from the operating state of the internal combustion engine. The control device for an internal combustion engine according to any one of claims 1 to 3 , wherein the temperature of the engine is estimated. 6. The control apparatus for an internal combustion engine according to claim 5 , wherein the temperature estimation means includes means for estimating the in-cylinder temperature based on a load factor and a rotational speed of the internal combustion engine and an air-fuel ratio.

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