JP2018091187A - Control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of an internal combustion engine which can accurately control a fuel injection amount of a port injection valve even if fuel pressure pulsation is generated in a low-pressure fuel passage resulting from a high-pressure pump.SOLUTION: A control device of an internal combustion engine calculates a start crank angle in the case that a value which is obtained by subtracting a temporary injection amount from a reference crank angle up to the start crank angle being a crank angle corresponding to the start-scheduled timing of the fuel injection of a port injection valve from a temporary injection amount from a reference crank angle corresponding to an initial stage of pulsation up to a finish crank angle is considered to be equal to a required injection amount on the basis of a formula including a formula which is obtained by modeling the finish crank angle and the pulsation when a rotation number of an internal combustion engine belongs to a pulsation increase area, and when the rotation number of the internal combustion engine does not belong to the pulsation increase area, calculates the start crank angle on the basis of the finish crank angle, the required injection amount and a detection value which is obtained immediately before the crank angle which goes back by a crank angle range corresponding to a maximum value of a target electricity-carrying period of the port injection valve from the finish crank angle.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a control device for an internal combustion engine.

  An internal combustion engine having an in-cylinder injection valve and a port injection valve is known. In such an internal combustion engine, the fuel sucked up by the low pressure pump is supplied to the port injection valve through the low pressure fuel passage, and the fuel further pressurized by the high pressure pump is supplied to the in-cylinder injection valve through the high pressure fuel passage. Is done. In such a configuration, the fuel injection amount of the port injection valve is controlled based on the detection value of the fuel pressure sensor that detects the pressure of the fuel supplied to the port injection valve.

  Here, Patent Document 1 discloses that the fuel injection amount is corrected based on the differential pressure between the fuel pressure and the pressure in the intake passage in order to control the fuel injection amount of the port injection valve with higher accuracy. ing.

JP-A-7-208236

  Here, in the above configuration, the fuel pressure may pulsate in the low pressure fuel passage mainly due to driving of the high pressure pump. During such pulsation, the fuel pressure fluctuates in a short period of time, so the actual fuel pressure changes from when the detected value of the fuel pressure sensor is acquired until fuel injection is performed, and also during injection. The actual fuel pressure may change. In the technique of Patent Document 1, since the fuel injection amount is corrected without considering such pulsation, there is a possibility that the fuel injection amount of the port injection valve cannot be accurately controlled when pulsation occurs.

  Therefore, an object of the present invention is to provide a control device for an internal combustion engine that can accurately control the fuel injection amount of a port injection valve even when fuel pressure pulsation occurs in a low-pressure fuel passage due to a high-pressure pump. To do.

但し、θ［ｄｅｇ］はクランク角、Ｐ（θ）［ｋＰａ］はクランク角θ［ｄｅｇ］に対応した燃圧値、Ａ［ｋＰａ］は前記脈動の振幅、ｃはクランク角３６０度当たりの前記高圧ポンプによる燃料の吐出回数、Ｂ［ｄｅｇ］は前記脈動の初期位相、Ｐ_ｃ［ｋＰａ］は前記脈動の中心燃圧値、Ｑ_ｐ［ｍＬ］は前記仮噴射量、ｋ［ｍＬ・ｍｉｎ^−１・ｋＰａ^−０．５］は定数、Ｎｅ［ｒｐｍ］は前記内燃機関の回転数である。 The above object is achieved by an in-cylinder injection valve that directly injects fuel into the cylinder of the internal combustion engine, a port injection valve that injects fuel into the intake port of the internal combustion engine, a low-pressure pump that pressurizes the fuel, and the low-pressure pump. A low-pressure fuel passage that supplies pressurized fuel to the plurality of port injection valves, and a fuel that is driven in conjunction with the internal combustion engine, further pressurizes the fuel supplied from the low-pressure fuel passage, and has a fuel pressure in the low-pressure fuel passage. A high-pressure pump that generates pulsation of the fuel, a high-pressure fuel passage that branches from the low-pressure fuel passage and that supplies fuel pressurized by the high-pressure pump to the plurality of in-cylinder injection valves, and a crank angle of the internal combustion engine is detected A crank angle sensor that detects the fuel pressure in the low-pressure fuel passage, a detection value acquisition unit that acquires detection values of the fuel pressure sensor at regular sampling time intervals, and the internal combustion engine Based on the state, a required injection amount calculation unit that calculates a required injection amount required for the port injection valve, and an end crank angle that is a crank angle corresponding to a scheduled end timing of fuel injection of the port injection valve are acquired. It is determined whether the rotational speed of the internal combustion engine calculated based on the acquisition unit and the output of the crank angle sensor belongs to a pulsation increasing range where the pulsation increases compared to other rotational speed ranges of the internal combustion engine. And a formula (2) that can calculate the temporary injection amount when the port injection valve temporarily injects fuel in an arbitrary crank angle range. A storage unit;
If an affirmative determination is made by the pulsation determining unit, based on the acquired end crank angle and the expression (2), a temporary crank angle from the reference crank angle corresponding to the initial phase of the pulsation to the end crank angle is determined. The value obtained by subtracting the temporary injection amount from the reference crank angle to the start crank angle that is the crank angle corresponding to the scheduled fuel injection start timing of the port injector from the injection amount is regarded as equal to the required injection amount. When the start crank angle is calculated and the pulsation determining unit makes a negative determination, the port injection valve is calculated from the acquired end crank angle, the required injection amount, and the end crank angle. The start crank angle is calculated based on the detected value acquired immediately before the crank angle that is back by the crank angle range corresponding to the maximum value that the target energization period can take. A calculation unit, a target energization period conversion unit that converts a crank angle range from the start crank angle to the end crank angle into a target energization period, and fuel injection by energizing the port injection valve for the target energization period And an injection control unit that performs the control.

However, θ [deg] is the crank angle, P (θ) [kPa] is the fuel pressure value corresponding to the crank angle θ [deg], A [kPa] is the amplitude of the pulsation, and c is the high pressure per 360 degrees of the crank angle. The number of fuel discharges by the pump, B [deg] is the initial phase of the pulsation, P _c [kPa] is the central fuel pressure value of the pulsation, Q _p [mL] is the temporary injection amount, k [mL · min ⁻¹ · kPa ^−0.5 ] is a constant, and Ne [rpm] is the rotational speed of the internal combustion engine.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a case where fuel pressure pulsation arises in a low-pressure fuel channel due to a high-pressure pump, it is possible to provide a control device for an internal combustion engine that can accurately control the fuel injection amount of a port injector.

FIG. 1 is a schematic configuration diagram of a control device according to the present embodiment. FIG. 2 is a waveform diagram of fuel pressure. FIG. 3 is a graph showing an example of the waveform of the fuel pressure pulsation and the injection period by the port injection valve. FIG. 4A is a graph showing a plurality of detected values acquired by the ECU, and FIG. 4B is a graph showing modeled fuel pressure pulsation. FIG. 5 is a flowchart illustrating an example of port injection control. FIG. 6 is a flowchart illustrating an example of the target energization period calculation process. 7A to 7C are graphs showing the fuel pressure waveform, the required injection amount, and the temporary injection amount.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a control device 1 of the present embodiment. The control device 1 includes an engine 10 and an ECU (Electronic Control Unit) 41 that controls the engine 10. The engine 10 is a spark ignition type in-line four-cylinder engine including a cylinder group 11 including cylinders 111 to 114 arranged in series, an in-cylinder injection valve group 37, and a port injection valve group 27. The engine 10 is an example of an internal combustion engine. The control device 1 is an example of a control device for an internal combustion engine.

  The in-cylinder injection valve group 37 includes in-cylinder injection valves 371 to 374 that inject fuel into the cylinders 111 to 114, respectively. The port injection valve group 27 includes port injection valves 271 to 274 for injecting fuel into the intake ports 13 communicating with the cylinders 111 to 114, respectively. Each of the in-cylinder injection valve group 37 and the port injection valve group 27 is an electromagnetically driven on-off valve in which the fuel injection amount is adjusted by energizing the electromagnetic coil in a predetermined energization period to separate the valve body from the valve seat. It is.

  The engine 10 is formed with an intake passage 12 having a plurality of intake ports 13 corresponding to each of the cylinder groups 11 and an exhaust passage having a plurality of exhaust ports (not shown). In each of the cylinder groups 11, a piston (not shown) is accommodated to define a combustion chamber. The combustion chamber is opened and closed by an intake valve and an exhaust valve. Further, the engine 10 includes a spark plug (not shown). The engine 10 includes a crankshaft 14 that is linked to a plurality of pistons, and a camshaft 15 that is linked to the crankshaft 14 and drives an intake valve or an exhaust valve. Further, a crank angle sensor 14a for detecting the rotation angle of the crankshaft 14 is provided. The resolution of crank angle detection by the crank angle sensor 14a is preferably a high resolution of, for example, about 1 degree, but is not limited thereto.

  The control device 1 also includes a fuel tank 21, a low pressure pump 22, a pressure regulator 23, a low pressure fuel pipe 25, a low pressure delivery pipe 26, and a fuel pressure sensor 28.

  The fuel tank 21 stores gasoline as fuel. The low pressure pump 22 pressurizes the fuel and discharges it into the low pressure fuel pipe 25. The pressure regulator 23 regulates the fuel discharged into the low-pressure fuel pipe 25 to a preset supply pressure on the low-pressure side.

  The low-pressure fuel pipe 25 and the low-pressure delivery pipe 26 are an example of a low-pressure fuel passage that supplies the fuel discharged from the low-pressure pump 22 to the port injection valve group 27. The fuel pressurized to a predetermined pressure level by the low-pressure pump 22 and adjusted to the low-pressure supply pressure by the pressure regulator 23 is introduced into the low-pressure delivery pipe 26 via the low-pressure fuel pipe 25.

  The port injection valve group 27 is connected to the low pressure delivery pipe 26 and injects fuel into the intake ports 13 corresponding to the cylinder groups 11 respectively. The fuel pressure sensor 28 detects the fuel pressure value in the low pressure delivery pipe 26, as will be described in detail later. The detected value of the fuel pressure sensor 28 is acquired by the ECU 41 at regular sampling time intervals.

  The control device 1 also includes a high pressure pump 31, a high pressure fuel pipe 35, a high pressure delivery pipe 36, and a fuel pressure sensor 38.

  The high pressure pump 31 sucks fuel from the branch pipe 25 a branched from the low pressure fuel pipe 25 and pressurizes the fuel to a high pressure level higher than the supply pressure level from the low pressure pump 22. The branch pipe 25a is provided with a pulsation damper 29 for suppressing fuel pressure pulsation in the branch pipe 25a.

  Specifically, the high-pressure pump 31 includes a pump housing 31h, a plunger 31p that can slide in the pump housing 31h, and a pressurizing chamber 31a defined between the pump housing 31h and the plunger 31p. The volume of the pressurizing chamber 31a changes according to the displacement of the plunger 31p. Fuel pressurized by the low-pressure pump 22 is introduced into the pressurizing chamber 31a via the branch pipe 25a in a state where an electromagnetic valve 32 described later is opened. The fuel in the pressurizing chamber 31a is pressurized to a high pressure by the plunger 31p and discharged into the high-pressure fuel pipe 35.

  A cam CP for driving the plunger 31p is mounted on the cam shaft 15 of the engine 10. The shape of the cam CP is a substantially square with rounded corners. The high-pressure pump 31 includes a follower lifter 31f that is moved up and down by the cam CP, and a spring 31g that biases the follower lifter 31f toward the cam CP. The plunger 31p is interlocked with the follower lifter 31f, and the plunger 31p is also moved up and down together with the follower lifter 31f. The camshaft 15 is interlocked with the crankshaft 14 via a chain or a belt. The cam shaft 15 and the cam CP are driven at a rotational speed that is ½ of the rotational speed of the crankshaft 14.

  An electromagnetic valve 32 is provided at the fuel inlet of the pressurizing chamber 31a of the high-pressure pump 31. The electromagnetic valve 32 includes a valve body 32v, a coil 32c that drives the valve body 32v, and a spring 32k that always biases the valve body 32v in the opening direction. Energization of the coil 32 c is controlled by the ECU 41 via the driver circuit 42. When the coil 32c is energized, the valve body 32v shuts off the branch pipe 25a and the pressurizing chamber 31a of the low-pressure fuel pipe 25 against the urging force of the spring 32k. In a state where the coil 32c is not energized, the valve body 32v is kept open by the urging force of the spring 32k.

  A high pressure fuel pipe 35 between the high pressure pump 31 and the in-cylinder injection valve group 37 is provided with a check valve 34 with a spring. The check valve 34 opens when the fuel pressure in the high-pressure pump 31 is higher than the fuel pressure in the high-pressure fuel pipe 35 by a predetermined amount.

  In the suction stroke of the high-pressure pump 31, the solenoid valve 32 is opened and the plunger 31p is lowered, and fuel is charged into the pressurizing chamber 31a from the branch pipe 25a of the low-pressure fuel pipe 25. In the pressurizing stroke, the electromagnetic valve 32 is closed and the volume of the pressurizing chamber 31a is reduced as the plunger 31p is raised, and the fuel in the pressurizing chamber 31a is pressurized. In the discharge stroke, the check valve 34 is opened when the force of the fuel pressure in the pressurizing chamber 31a becomes larger than the biasing force of the spring of the check valve 34, and the pressurized fuel is supplied to the high pressure fuel pipe 35 and the high pressure delivery pipe 36. Supplied to. As described above, the raising / lowering of the plunger 31p is realized by the rotation of the cam CP. Since the cam CP is linked to the crankshaft 14 via the camshaft 15, the high-pressure pump 31 is driven to be linked to the crankshaft 14. The

  In this case, the solenoid valve 32 is opened when not energized, but is not limited thereto. For example, the solenoid valve 32 may be in a closed state with no energization, with the urging directions of the coil 32c and the spring 32k reversed. In this case, the coil 32c is energized during the fuel intake stroke, and is de-energized during the pressurization and discharge strokes.

  High pressure fuel pressurized by the high pressure pump 31 is stored in the high pressure delivery pipe 36 via the high pressure fuel pipe 35. The high-pressure fuel pipe 35 and the high-pressure delivery pipe 36 are an example of a high-pressure fuel passage that supplies high-pressure fuel from the high-pressure pump 31 to the cylinder injection valves 371 to 374.

  The in-cylinder injection valve group 37 directly injects high-pressure fuel from the high-pressure delivery pipe 36 into each of the cylinders 111 to 114 in a predetermined order. The fuel pressure sensor 38 detects the fuel pressure in the high-pressure delivery pipe 36, and the detected value of the fuel pressure sensor 38 is acquired by the ECU 41 at regular sampling time intervals.

  The ECU 41 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). The ECU 41 executes port injection control, which will be described later, based on information from the sensor, information stored in the ROM in advance, and the like according to a control program stored in the ROM in advance. This control is functionally realized by the CPU, ROM, and RAM. The required injection amount calculation unit, the acquisition unit, the storage unit, the calculation unit, the target energization period conversion unit, the injection control unit, the detection value acquisition unit, and the model calculation This is executed by the discharge unit, the discharge number storage unit, the pulsation determination unit, and the injection start determination unit. Details will be described later.

  The ECU 41 calculates a required fuel injection amount required for each of the port injection valve groups 27 based on the operating state of the engine 10. Further, the ECU 41 calculates each energization period to the port injection valve group 27 corresponding to the requested injection amount, and energizes each of the port injection valve groups 27 in a predetermined order at a predetermined crank angle interval for the calculated energization period. To do. Thereby, port injection is realized with an injection amount corresponding to the required injection amount. The same applies to the in-cylinder injection valve group 37.

  The opening period of each fuel injection valve is proportional to the energization period to the electromagnetic coil of the fuel injection valve. Therefore, the ECU 41 calculates each energization period of the port injection valve group 27 according to the required injection amount based on the detection value of the fuel pressure sensor 28. Similarly, the ECU 41 calculates each energization period of the in-cylinder injection valve group 37 according to the required injection amount based on the detection value of the fuel pressure sensor 38. The ECU 41 issues a command to the driver circuit 42 according to the calculated energization period. The driver circuit 42 energizes each of the port injection valve group 27 and the in-cylinder injection valve group 37 for the calculated energization period in accordance with a command from the ECU 41. In this way, the fuel injection amount of each fuel injection valve is controlled.

  Next, fuel pressure pulsation caused by the high pressure pump 31 will be described. FIG. 2 is a waveform diagram of fuel pressure. The vertical axis represents the fuel pressure, and the horizontal axis represents the engine speed. As shown in FIG. 2, the engine speed range includes a pulsation increasing region in which the amplitude of the fuel pressure pulsation increases in the low pressure fuel pipe 25 and the low pressure delivery pipe 26 as compared with other regions. The pulsation increasing range is, for example, an engine speed of 800 to 1400 rpm, but is not limited thereto.

  The reason why the amplitude of the fuel pressure pulsation increases as described above can be considered as follows. In a predetermined region of the engine speed, the in-cylinder injection valve group 37 is not used and fuel injection is performed by the port injection valve group 27. In the meantime, the in-cylinder injection valve group 37 is not used, so that the solenoid valve 32 is maintained in the open state, and the plunger 31p repeatedly moves up and down by the power of the engine 10. For this reason, the suction and discharge of fuel are repeated between the low-pressure fuel pipe 25 and the pressurizing chamber 31a, thereby increasing the amplitude of pulsation and propagating to the low-pressure delivery pipe 26. Further, when the frequency of the fuel pressure pulsation and the natural frequency of the pulsation damper 29 coincide with each other and resonate, the amplitude of the fuel pressure pulsation further increases.

  FIG. 3 is a graph showing an example of the waveform of the fuel pressure pulsation and the energization period by the port injection valve. The vertical axis represents fuel pressure, and the horizontal axis represents time. FIG. 3 shows a pulsation waveform in a state where the engine speed belongs to the above-described pulsation increasing region. Here, the fuel pressure value PA is an actual fuel pressure value during energization, that is, during the port injection period, and the detection value PS is a detection value of the fuel pressure sensor 28 acquired by the ECU 41. Generally, the energization period of port injection is calculated based on the detection value PS acquired before the start of port injection, and the port injection amount is controlled. This is because the ECU 41 needs to complete the calculation of the energization period based on the acquired detection value of the fuel pressure sensor 28 before the port injection reaches the start timing. Further, the ECU 41 can acquire the detection value of the fuel pressure sensor 28 only at a constant sampling time interval. However, when the engine speed belongs to the above-described pulsation increasing region, the fuel pressure fluctuates in a short time, and even during the injection, so that the detected value PS and the fuel pressure value PA are shown in FIG. And the difference may increase. For this reason, if the energization period is calculated based on the detection value PS, the port injection amount may not be accurately controlled.

  In the present embodiment, the ECU 41 calculates a target energization period of the port injector based on a calculation formula including a model formula described later. Thereby, even if it is a case where the fuel pressure pulsation has generate | occur | produced, each injection amount of the port injection valve group 27 can be controlled accurately. First, the model formula will be described. In the following description, “detected value” means the detected value of the fuel pressure sensor 28 unless otherwise specified.

ここで、θ［ｄｅｇ］はクランク角である。Ｐ（θ）［ｋＰａ］は、クランク角θに対応した燃圧値である。Ａ［ｋＰａ］は、脈動の振幅である。Ｂ［ｄｅｇ］は、脈動の初期位相である。ｃは、クランク角３６０度当たりの高圧ポンプ３１の燃料の吐出回数であり、換言すれば、クランク角３６０度当たりの脈動の振動数である。Ｐ_ｃ［ｋＰａ］は、脈動の中心燃圧値である。中心燃圧値Ｐ_ｃは、振幅Ａの中心値である。初期位相Ｂは、クランク角θがゼロ度に最も近くて振幅Ａが極大値をとる際のクランク角である。尚、クランク角θがゼロ度になる時は、気筒１１１のピストンが圧縮行程の上死点に位置する時である。 As described above, the ECU 41 acquires detection values at regular sampling time intervals. FIG. 4A is a graph showing a plurality of detection values acquired by the ECU 41. FIG. 4B is a graph showing pulsations modeled based on a plurality of detection values. 4A and 4B, the vertical axis represents the fuel pressure and the horizontal axis represents the crank angle. The model expression of pulsation is expressed as follows.

Here, θ [deg] is a crank angle. P (θ) [kPa] is a fuel pressure value corresponding to the crank angle θ. A [kPa] is the amplitude of pulsation. B [deg] is an initial phase of pulsation. c is the number of times the fuel is discharged from the high-pressure pump 31 per 360 ° crank angle, in other words, the pulsation frequency per 360 ° crank angle. P _c [kPa] is the central fuel pressure value of pulsation. The central fuel pressure value _Pc is the central value of the amplitude A. The initial phase B is a crank angle when the crank angle θ is closest to zero degrees and the amplitude A takes a maximum value. The crank angle θ is zero degrees when the piston of the cylinder 111 is located at the top dead center of the compression stroke.

The reason why the fuel pressure pulsation can be modeled by an equation using a trigonometric function is that the pulsation periodically changes due to the rotation of the cam CP of the high-pressure pump 31 as described above. Here, the center fuel pressure value P _c , the amplitude A, and the initial phase B are calculated by the ECU 41 based on the detection value of the fuel pressure sensor 28 and the like, as will be described in detail later.

  The number of discharges c is stored in advance in the ROM of the ECU 41. Here, the number of discharges c is determined by the shape of the cam CP of the high-pressure pump 31. In this embodiment, the shape of the cam CP is a substantially square with rounded corners. Therefore, the cam CP rotates 180 degrees per 360 degrees of crank angle and discharges fuel twice. Therefore, in the present embodiment, the number of ejections c is 2. The ROM of the ECU 41 is an example of a discharge number storage unit that stores the number of times of fuel discharge c by the cam CP per crank angle of 360 degrees. In the case of a substantially equilateral triangular cam with rounded corners, the cam rotates 180 degrees per 360 degrees of crank angle, and the number of discharges c is 1.5. In the case of a substantially elliptic cam, the number of discharges c per crank angle of 360 degrees is 1.

  Next, port injection control will be described. FIG. 5 is a flowchart illustrating an example of port injection control. In the following description, “previous value”, “previous value”, and “current value” mean the detected values of the fuel pressure sensor 28 acquired by the ECU 41 the previous time, previous time, and this time, respectively. The “next value” means a detection value of the fuel pressure sensor 28 that the ECU 41 is scheduled to acquire next time.

  The ECU 41 determines whether or not the engine speed [rpm] calculated based on the crank angle sensor 14a is less than a predetermined threshold (step S1). Here, the threshold value is defined as the upper limit of the engine speed at which port injection can be required, and is set to a value larger than the engine speed in the above-described pulsation increasing region. If the determination is negative, the port injection is not executed and this control is terminated.

If the determination in step S1 is affirmative, the ECU 41 acquires a predetermined number of detection values and stores them in the RAM (step S2). When a predetermined number of detection values already acquired are stored in the RAM, the detection values are updated in order from the newly acquired detection values. The predetermined number is the number of detected values necessary for calculating the central fuel pressure value _Pc , as will be described in detail later. Further, the process of step S2 is also executed for calculating the amplitude A and the initial phase B. The detection values acquired and stored in step S2 include at least two previous detection values, the previous value and the current value. The process of step S2 is an example of a process executed by an acquisition unit that acquires the detection value of the fuel pressure sensor 28 at a constant sampling time interval.

Next, the ECU 41 executes a central fuel pressure calculation process for calculating the pulsation central fuel pressure value _Pc based on at least the previous value and the current value stored in the RAM in step S2 (step S3). Therefore, even when the engine speed does not belong to the above-described pulsation increase region, the central fuel pressure calculation process is executed. This is because each term of the model formula (3) can be immediately calculated when the engine speed belongs to the pulsation increasing region. The process of step S3 and the processes of steps S11 and S12, which will be described later, are executed by a model calculation unit that calculates the center fuel pressure value P _c , the amplitude A, and the initial phase B based on at least the detection values acquired last time and this time. It is an example of the process to perform. Details will be described later.

  A required fuel injection amount Q [mL] required for each of the port injection valve groups 27 is calculated based on the operating state of the engine 10, specifically, the engine speed, the intake air amount, the accelerator opening, and the like ( Step S4). The process of step S4 is an example of a process executed by a required injection amount calculation unit that calculates a required injection amount Q required for each of the port injection valve groups 27 based on the state of the engine 10.

Next, to obtain the finished crank angle theta _e the end of the injection port injector next injection schedule is scheduled (step S5). End crank angle theta _e is set according to the operating state of the engine 10, it is stored in the RAM. Further, the end crank angle θ _e is different for each of the port injection valves 271 to 274.

  Based on the output value from the crank angle sensor 14a, the ECU 41 stores the crank angle at the time of acquisition of the current value acquired in step S2 in the RAM (step S7). Each time a new detection value is acquired, the crank angle at the time of acquisition of the current value is updated. Next, the ECU 41 converts the sampling time interval stored in advance in the ROM into a crank angle based on the calculated latest engine speed (step S8). The reason for considering the engine speed is that the sampling speed interval is constant, but the engine speed fluctuates. Next, the ECU 41 adds the crank angle corresponding to the sampling time interval to the crank angle at the time of acquisition of the current value, and calculates the crank angle at the time of acquisition of the next value (step S9).

Then ECU41, based on the crank angle at the time of acquisition schedule the next value, crank from the end crank angle theta _e obtained in step S5, predated by crank angle range corresponding to the maximum value of the energization period may be calculated The angle is set as the temporary start crank angle _θsp, and it is determined whether or not the temporary start crank angle _θsp is before the crank angle at the time when the next value is scheduled to be acquired (step S10). The temporary start crank angle θ _sp is a crank angle corresponding to a scheduled start timing of temporary injection of the port injection valve when the energization period is temporarily maximized from the end crank angle θ _e . The processes in steps S7 to S9 are necessary for executing the determination process in step S10. If a negative determination is made in step S10, the processes after step S1 are executed again, and the central fuel pressure calculation process is continued.

  Next, the ECU 41 determines whether or not the engine speed belongs to the above-described pulsation increasing region (step S10a). The pulsation increasing region is calculated in advance by experiments and stored in the ROM. The processing in step S10a is executed by a pulsation determining unit that determines whether or not the engine speed calculated based on the output of the crank angle sensor 14a belongs to a pulsation increasing region where pulsation increases compared to other rotational speed regions. It is an example of the process to perform.

ここで、Ｑ［ｍＬ］は、ステップＳ４で算出された要求噴射量である。Ｐ［ｋＰａ］は、燃料噴射の制御の対象となるポート噴射弁の噴射開始の直前に取得された燃圧センサ２８の検出値である。具体的には、ステップＳ１０で肯定判定された場合での、今回取得された検出値である。更に詳細には、終了クランク角θ_ｅから、算出され得る通電期間の最大値に対応するクランク角範囲だけ遡ったクランク角である仮開始クランク角θ_ｓｐの直前に取得された検出値である。τ［ｍｓ］は、ポート噴射弁の目標通電期間である。ｋ［ｍＬ・ｍｉｎ^−１・ｋＰａ^−０．５］は定数であり、ｋ＝Ｑ_ＩＮＪ／√Ｐ_０が成立する。ここで、Ｑ_ＩＮＪ［ｍＬ・ｍｉｎ^−１］はポート噴射弁の公称流量であり、Ｐ_０［ｋＰａ］は公称流量に対応した検査圧力である。定数ｋは、予め実験により算出されて、ポート噴射弁群２７のそれぞれに対応付けされてＲＯＭに記憶されている。尚、式（４）の右辺では６０及び１０００が乗算されており、これにより式（４）の右辺の値は目標通電期間τと同じ単位であるミリ秒に換算されている。また本処理では、算出された目標通電期間τに基づいて、開始クランク角θ_ｓが算出される。開始クランク角θ_ｓとは、次回噴射予定のポート噴射弁の噴射の開始が予定されているタイミングに対応したクランク角である。開始クランク角θ_ｓは、終了クランク角θ_ｅから、算出された目標通電期間τに対応するクランク角範囲だけ遡ったクランク角である。その後に、ステップＳ１４及びＳ１５の処理が実行される。ステップＳ１４及びＳ１５については後述する。 If a negative determination is made in step S10a, the ECU 41 determines that the target energization period τ of the port injector is not based on the above-described model equation (3) but based on the equation (4), assuming that the fuel pressure does not vary greatly. A target energization period calculation process to be calculated is executed (step S10b).

Here, Q [mL] is the required injection amount calculated in step S4. P [kPa] is a detection value of the fuel pressure sensor 28 acquired immediately before the start of injection of the port injection valve that is the target of fuel injection control. Specifically, it is the detection value acquired this time when an affirmative determination is made in step S10. More particularly, from the end crank angle theta _e, which is the detection value obtained immediately before the provisional start crank angle theta _sp is a crank angle back by crank angle range corresponding to the maximum value of the energization period may be calculated. τ [ms] is a target energization period of the port injection valve. k [mL · min ⁻¹ · kPa ^−0.5 ] is a constant, and k = Q _INJ / √P ₀ is established. Here, Q _INJ [mL · min ⁻¹ ] is a nominal flow rate of the port injection valve, and P ₀ [kPa] is an inspection pressure corresponding to the nominal flow rate. The constant k is calculated in advance through experiments and is stored in the ROM in association with each of the port injection valve groups 27. Incidentally, 60 and 1000 are multiplied on the right side of the equation (4), whereby the value on the right side of the equation (4) is converted to milliseconds, which is the same unit as the target energization period τ. In this process, the start crank angle θ _s is calculated based on the calculated target energization period τ. The start crank angle θ _s is a crank angle corresponding to the timing at which the start of the injection of the port injection valve scheduled for the next injection is scheduled. The start crank angle θ _s is a crank angle that goes back from the end crank angle θ _e by a crank angle range corresponding to the calculated target energization period τ. Thereafter, the processes of steps S14 and S15 are executed. Steps S14 and S15 will be described later.

  When the amplitude of the pulsation is relatively small, the difference between the detected value immediately before the start of injection and the fuel pressure value during port injection is also small, so an appropriate target energization period can be obtained without using the above-described model equation (3). Can be calculated. Moreover, since the model formula (3) is not used, an increase in processing load is suppressed.

  If the determination in step S10a is affirmative, the ECU 41 executes an amplitude calculation process for calculating the amplitude A of the pulsation based on at least the previous value and the current value stored in the RAM in step S2 (step S11). Next, the ECU 41 executes a phase calculation process for calculating the initial phase B based on at least one of the previous value and the current value stored in the RAM in step S2 (step S12). The details of the amplitude calculation process and the phase calculation process will be described later. As described above, each term of the model formula (3) is calculated based on the processes of steps S3, S11, and S12.

  Next, the ECU 41 executes a target energization period calculation process for calculating a target energization period τ of the port injection valve based on a calculation formula described later (step S13). In the processing in step S13, the target energization period τ is calculated based on the calculation formula including the model formula (3) without using the above-described formula (4). Details will be described later.

Then ECU41 determines, based on the value detected by the crank angle sensor 14a, whether the crank angle at the present time has reached the start crank angle theta _s (step S14). If a negative determination is made in step S14, the process of step S14 is executed again. If the determination in step S14 is affirmative, the ECU 41 conducts port injection by energizing the port injection valve scheduled for injection for the target energization period τ calculated in step S13 (step S15). The process of step S15 is an example of a process executed by an injection control unit that performs fuel injection by energizing the port injection valve for the target energization period τ. In this way, port injection control is executed.

ここで、Ｎｅ［ｒｐｍ］はエンジン回転数である。単位分当たりの回転数を示すエンジン回転数Ｎｅに３６０を乗算することにより、単位分当たりでのクランク軸１４の回転角度［ｄｅｇ］に換算されている。ｋ［ｍＬ・ｍｉｎ^−１・ｋＰａ^−０．５］は上述した定数である。Ｐ（θ）［ｋＰａ］は、上述したモデル式（３）である。 Next, the target energization period calculation process in step S13 will be described. In this control, based on the following calculation formula (5) including the model formula (3), a temporary injection amount Q _p [mL] when the port injection valve temporarily injects fuel in an arbitrary crank angle range is calculated. Is done.

Here, Ne [rpm] is the engine speed. The rotation speed [deg] of the crankshaft 14 per unit minute is converted by multiplying 360 by the engine speed Ne indicating the rotation speed per unit minute. k [mL · min ⁻¹ · kPa ^−0.5 ] is the constant described above. P (θ) [kPa] is the model equation (3) described above.

  The calculation formula (5) is derived as follows. According to the above-described equation (4), the injection amount per unit can be expressed as k√P. Using the above-described model equation (3) and the engine speed Ne, the injection amount per unit crank angle can be expressed as {k / (360 · Ne)} × √P (θ). Here, (360 · Ne) means the rotation angle [deg] of the crankshaft 14 per unit. Therefore, by integrating the expression indicating the injection amount per unit crank angle in an arbitrary crank angle range, the injection amount in the crank angle range can be calculated. The calculation formula (5) is stored in the ROM of the ECU 41. Accordingly, the ROM of the ECU 41 can calculate a temporary injection amount when the port injection valve temporarily injects fuel in an arbitrary crank angle range, and stores a formula (2) including the formula (1) modeling the pulsation. It is an example.

しかしながら、式（６）に基づいて開始クランク角θ_ｓを算出しようとすると、計算が複雑になりＥＣＵ４１の処理負荷が増大する可能性がある。従って、本実施例では以下のようにして開始クランク角θ_ｓが算出されて目標通電期間τが算出される。 Here, in order to calculate the target energization period τ corresponding to the required injection amount Q to the port injection valve, the start crank when the temporary injection amount calculated by the calculation formula (5) becomes the required injection amount Q. It is only necessary to know the angle θ _s and the end crank angle θ _e . In the present embodiment an end crank angle theta _e is already acquired in step S5, the start crank angle theta _s may if calculated. Therefore, it is conceivable to calculate the starting crank angle θ _s when the following expression is satisfied.

However, if the start crank angle θ _s is calculated based on the equation (6), the calculation becomes complicated and the processing load on the ECU 41 may increase. Therefore, in this embodiment, the start crank angle θ _s is calculated as follows, and the target energization period τ is calculated.

ここで、基準クランク角θ_Ｂは、初期位相Ｂに対応したクランク角であり、（θ_Ｂ−Ｂ）＝０となる。このため、式（７）での三角関数の積分値の算出が容易となり、仮噴射量Ｑ_ｅを算出することによるＥＣＵ４１への処理負荷の増大は抑制されている。 FIG. 6 is a flowchart illustrating an example of the target energization period calculation process. Based on the above calculation formula (5), the ECU 41 supposes that the port injection valve scheduled for the next injection temporarily supplies fuel in the crank angle range from the reference crank angle θ _B to the end crank angle θ _e acquired in step S5. calculating a tentative injection amount _{Q e} in case of injection (step S21). The temporary injection amount Q _e can be expressed by the following integral formula.

Here, the reference crank angle θ _B is a crank angle corresponding to the initial phase B, and (θ _B −B) = 0. Therefore, the calculation of the integral value of the trigonometric function in equation (7) is facilitated, increase in the processing load of the ECU41 by calculating the tentative injection amount Q _e is suppressed.

ここで仮噴射量Ｑ_ｓは以下の積分の式で表すことができる。

上述したように（θ_Ｂ−Ｂ）＝０であるため、式（９）の三角関数の積分値の算出が容易となり、開始クランク角θ_ｓを算出することによるＥＣＵ４１への処理負荷の増大は抑制されている。ステップＳ２１及びＳ２２は、取得された終了クランク角θ_ｅと式（２）に基づいて、脈動の初期位相Ｂに対応した基準クランク角θ_Ｂから終了クランク角θ_ｅまでの仮噴射量Ｑ_ｅから、基準クランク角θ_Ｂから開始クランク角θ_ｓまでの仮噴射量Ｑ_ｓを減算した値が、要求噴射量Ｑに等しいとみなした場合での、開始クランク角θ_ｓを算出する算出部が実行する処理の一例である。 Next, the ECU 41 subtracts the temporary injection amount Q _s from the temporary injection amount Q _e from the reference crank angle θ _B to the end crank angle θ _e to be equal to the required injection amount Q calculated in step S4. In this case, the starting crank angle θ _s is calculated (step S22). That is, the start crank angle θ _s is calculated when the following equation is satisfied.

Here, the temporary injection amount Q _s can be expressed by the following integral formula.

As described above, since (θ _B −B) = 0, it is easy to calculate the integral value of the trigonometric function of Equation (9), and an increase in the processing load on the ECU 41 by calculating the start crank angle θ _s It is suppressed. Steps S21 and S22, based on the obtained finished crank angle theta _e and Equation (2), from the temporary injection amount Q _e from the reference crank angle theta _B corresponding to the initial phase B of the pulsation to the end crank angle theta _e When the value obtained by subtracting the temporary injection amount Q _s from the reference crank angle θ _B to the start crank angle θ _s is considered to be equal to the required injection amount Q, a calculation unit that calculates the start crank angle θ _s is executed. It is an example of the process to perform.

FIGS. 7A to 7C are graphs showing the fuel pressure waveform, the required injection amount Q, and the temporary injection amounts Q _s and Q _e . 7A to 7C are graphs for facilitating understanding of these relationships. The horizontal axis in FIGS. 7A to 7C is the crank angle, the vertical axis in FIG. 7A is the fuel pressure, and the vertical axis in FIGS. 7B and 7C is the injection amount [mL]. is there. Figure 7 (B) the provisional injection amount Q _e, FIG. 7 (C) in the temporary injection amount Q _s and the required injection amount Q, are shown in the area, respectively. The injection amounts shown in FIGS. 7B and 7C indicate the total injection amount obtained by integrating the injection amount for each unit crank angle in the crank angle range. As shown in FIG. 7 (B) and FIG. 7 (C), the ends crank angle theta _e in the case where the above equation (7) is satisfied, it ends in the case where the port injection valve to inject only the required injection amount Q It is a crank angle. FIG. 7A illustrates the timing at which the engine speed Ne closest to the start crank angle θ _s used for calculating the temporary injection amounts Q _s and Q _e is calculated.

上述したように、エンジン回転数Ｎｅ［ｒｐｍ］に３６０を乗算することにより、エンジン回転数をクランク軸１４の回転角度［ｄｅｇ］に換算できる。またエンジン回転数Ｎｅ［ｒｐｍ］を６０で除算し更に１０００で除算することにより、単位分当たりのエンジン回転数を単位ミリ秒当たりのエンジン回転数に換算できる。これにより、開始クランク角θ_ｓから終了クランク角θ_ｅまでのクランク角範囲に対応した目標通電期間τ［ｍｓ］を算出できる。尚、ポート噴射は、一般的には、各気筒の吸気行程中に開始して終了するため、開始クランク角θ_ｓから終了クランク角θ_ｅまでのクランク角範囲に、クランク角がゼロ度である上死点が含まれることはない。このため、上記（θ_ｅ−θ_ｓ）は正の値［ｄｅｇ］をとる。ステップＳ２３の処理は、開始クランク角θ_ｓから終了クランク角θ_ｅまでのクランク角範囲を目標通電期間τに換算する目標通電期間換算部が実行する処理の一例である。 Then ECU41 is a crank angle range up to the start crank angle theta _s calculated from the end crank angle theta _e, converted into target energization period τ [ms] (step S23). Specifically, the target energization period τ is calculated based on the following formula.

As described above, by multiplying the engine speed Ne [rpm] by 360, the engine speed can be converted into the rotation angle [deg] of the crankshaft 14. Further, by dividing the engine speed Ne [rpm] by 60 and further by 1000, the engine speed per unit minute can be converted into the engine speed per unit millisecond. Accordingly, the target energization period τ [ms] corresponding to the crank angle range from the start crank angle θ _s to the end crank angle θ _e can be calculated. Note that port injection is generally for beginning and ending during the intake stroke of each cylinder, a crank angle range from the start crank angle theta _s until the end crank angle theta _e, crank angle is zero degrees Top dead center is not included. Therefore, the above (θ _e −θ _s ) takes a positive value [deg]. The process of step S23 is an example of a process executed by the target energization period conversion unit that converts the crank angle range from the start crank angle θ _s to the end crank angle θ _e into the target energization period τ.

  In this way, the target energization period τ corresponding to the required injection amount Q is calculated based on the calculation formula (5) including the model formula (3) considering the pulsation of the fuel pressure. For this reason, even when the engine speed belongs to the pulsation increasing region, the target energization period τ can be calculated with high accuracy, and thereby the port injection amount can be controlled with high accuracy. Therefore, the air-fuel ratio can be controlled with high accuracy.

Further, since the end crank angle θ _e is calculated based on the two temporary injection amounts Q _s and Q _e that can be expressed using the reference crank angle θ _B , an increase in the processing load of the ECU 41 is suppressed.

  Further, as described above, each term of the model formula (3) is calculated only in the case of an affirmative determination in steps S6 and S10, and the target energization period is calculated based on the calculation formula (5). For this reason, the target energization period is calculated based on the calculation formula (5) only when necessary, and an increase in the processing load on the ECU 41 is suppressed.

Next, the center fuel pressure calculation process will be described. The ECU 41 calculates the center fuel pressure value _Pc based on the last time value, the previous value, and the current value acquired in step S2 and the crank angle corresponding to the sampling time interval. Here, assuming that the crank angle t [deg] corresponding to the sampling time interval is a coefficient a, the previous value P ₁ [kPa], the previous value P ₂ [kPa], and the current value P ₃ [kPa] are as follows: It is expressed by the following formula.
P ₁ = Asin (a) + P _c
P ₂ = Asin (a + t) + P _c
P ₃ = Asin (a + 2t) + P _c
The coefficient a is represented by the previous value P ₁ , the previous value P ₂ , the current value P ₃ , and the crank angle t by the above three expressions, and the calculated coefficient a is substituted into any of the above three expressions. Thus, the central fuel pressure value _Pc can be calculated. Note that the crank angle t corresponding to the sampling time interval is calculated by the method of step S8 described above.

Further, the smoothed value of the detected value may be calculated as the central fuel pressure value _Pc . The annealing value is calculated from the current value, the previously calculated annealing value, and the annealing coefficient. The previously calculated annealing value is calculated based on the previous value. For this reason, the annealing value calculated this time is calculated based on the current value and the previous value. In addition, when the annealing value is calculated for the first time this time and there is no previously calculated annealing value, the previous value is used as the previously calculated annealing value. Therefore, when the smoothed value of the detected value is calculated as the central fuel pressure value Pc, the predetermined number in step S2 may be two or more.

Moreover, you may calculate the average value of the acquired detected value as the center fuel pressure value _Pc . For example, the number of samples of detection values used for calculation is based on a map in which the number of samples decreases as the engine speed increases so as to correspond to the number of detection values acquired during a period of approximately one cycle of pulsation. May be set. In this case, the predetermined number in step S2 is at least two.

式（１１）及び（１２）が中心燃圧値Ｐ_ｃを含んでいない理由は、中心燃圧値Ｐ_ｃをゼロとみなしても振幅Ａや初期位相Ｂの算出結果には影響がないからである。 Next, the amplitude calculation process will be described. Assuming that the respective crank angles at the time when the current value P _n and the previous value P _n−1 are acquired are θ _n and θ _n−1 , they can be expressed by the following equations.

Why the formula (11) and (12) does not contain a central fuel pressure value P _c is also regarded a central fuel pressure value P _c is zero because there is no effect on the calculation result of the amplitude A and the initial phase B.

このように振幅Ａは、中心燃圧値Ｐ_ｃを用いずに算出できるため、ＥＣＵ４１の処理負荷の増大が抑制されている。従って、ＥＣＵ４１は、前回値Ｐ_ｎ−１及び今回値Ｐ_ｎと、サンプリング時間間隔に対応するクランク角θ_ＡＤとに基づいて、振幅Ａを算出する。 Here, the crank angle θ _AD [deg] corresponding to the sampling time interval can be expressed as θ _AD = θ _n −θ _n−1 . Therefore, the amplitude A can be expressed as follows based on the equations (11) and (12).

Thus, since the amplitude A can be calculated without using the central fuel pressure value _Pc , an increase in the processing load of the ECU 41 is suppressed. Therefore, the ECU 41 calculates the amplitude A based on the previous value P _n−1 and the current value P _n and the crank angle θ _AD corresponding to the sampling time interval.

ここで、Ｂ^＋＝θ_ｎ＋｛ｃｏｓ^−１（Ｐ_ｎ／Ａ）×（１／ｃ）｝、Ｂ⁻＝θ_ｎ−｛ｃｏｓ^−１（Ｐ_ｎ／Ａ）×（１／ｃ）｝とする。尚、式（１４）において、クランク角θ_ｎ及び今回値Ｐ_ｎの代わりに、クランク角θ_ｎ−１及び前回値Ｐ_ｎ−１を用いてもよい。この場合も、理論上は初期位相Ｂの値は同じ値になる。 Next, the phase calculation process will be described. The ECU 41 calculates two candidates B ⁺ and B ⁻ for the initial phase B based on the following equation (14) calculated based on the equations (13) and (11).

Here, B ⁺ = θ _n + {cos ⁻¹ (P _n / A) × (1 / c)}, B ⁻ = θ _n − {cos ⁻¹ (P _n / A) × (1 / c)} And In the equation (14), the crank angle θ _n−1 and the previous value P _n−1 may be used instead of the crank angle θ _n and the current value P _n . Also in this case, the value of the initial phase B is theoretically the same value.

式（１５）の左辺にある、Ａｃｏｓ｛ｃ（θ_ｎ−１−Ｂ^＋）｝＋Ｐ_ｃは、上述した候補Ｂ^＋に基づいて算出された仮燃圧値を意味する。所定値ε［ｋＰａ］は、初期位相Ｂの真の解が候補Ｂ^＋である場合における、仮燃圧値と前回値Ｐ_ｎ−１との取り得る最大の誤差よりも若干大きい値であり、予め実験により算出されＲＯＭに記憶されている。式（１５）が成立する場合には、ＥＣＵ４１は候補Ｂ^＋が初期位相Ｂとして特定され、不成立の場合には候補Ｂ⁻が初期位相Ｂとして特定される。以上のように、簡易な不等号の式（１５）に基づいて最終的な初期位相Ｂを算出できるため、ＥＣＵ４１の処理負荷の増大が抑制されている。 Here, the true solution of the initial phase B is determined based on Expression (15).

A cos {c (θ _n−1 −B ⁺ )} + P _{c on} the left side of the equation (15) means a temporary fuel pressure value calculated based on the above-described candidate B ⁺ . The predetermined value ε [kPa] is a value that is slightly larger than the maximum possible error between the temporary fuel pressure value and the previous value P _n−1 when the true solution of the initial phase B is the candidate B ^+. It is calculated by experiment and stored in the ROM. If equation (15) is satisfied, ECU 41 candidate B ⁺ is identified as the initial phase B, and if not satisfied candidate B ^- is identified as the initial phase B. As described above, since the final initial phase B can be calculated based on the simple inequality expression (15), an increase in the processing load of the ECU 41 is suppressed.

In equation (15), the direction of the inequality sign may be reversed. In this case, the candidate if the expression (15) is satisfied B ^- is, in the case of not satisfied candidate B ⁺ is identified as the initial phase B. In the equation (15), the candidate B ⁻ may be used instead of the candidate B ⁺ . In this case, the candidate B ⁻ is satisfied when the equation (15) is satisfied, and the candidate B ⁺ is satisfied when the equation (15) is not satisfied. Is identified as the initial phase B. In the formula (15), in place of the previous value _{P n-1} and the crank angle theta _n-1, may be used current value _{P n} and the crank angle theta _n. Therefore, the ECU 41 determines one of the previous value P _n−1 and the current value P _n , the crank angle at the time when one is acquired, the number of discharges c, the calculated amplitude A, and the calculated center fuel pressure value. Based on P _c , the initial phase B is calculated.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

1 Control device (control device for internal combustion engine)
10 Engine (Internal combustion engine)
11 Cylinder Group 111-114 Cylinder 14 Crankshaft 14a Crank Angle Sensor 15 Camshaft 22 Low Pressure Pump 25 Low Pressure Fuel Pipe (Low Pressure Fuel Path)
26 Low pressure delivery pipe (low pressure fuel passage)
27 Port injection valve group 271 to 274 Port injection valve 28 Fuel pressure sensor 31 High pressure pump 35 High pressure fuel pipe (high pressure fuel passage)
36 High pressure delivery pipe (high pressure fuel passage)
37 In-cylinder injection valve group 41 ECU (required injection amount calculation unit, acquisition unit, storage unit, calculation unit, target energization period conversion unit, injection control unit, detection value acquisition unit, pulsation determination unit)
CP cam

Claims (1)

An in-cylinder injection valve that directly injects fuel into the cylinder of the internal combustion engine;
A port injection valve for injecting fuel into the intake port of the internal combustion engine;
A low pressure pump for pressurizing the fuel;
A low pressure fuel passage for supplying fuel pressurized by the low pressure pump to the plurality of port injection valves;
A high-pressure pump that is driven in conjunction with the internal combustion engine, further pressurizes the fuel supplied from the low-pressure fuel passage, and generates a pulsation of fuel pressure in the low-pressure fuel passage;
A high-pressure fuel passage branched from the low-pressure fuel passage and supplying fuel pressurized by the high-pressure pump to the plurality of in-cylinder injection valves;
A crank angle sensor for detecting a crank angle of the internal combustion engine;
A fuel pressure sensor for detecting a fuel pressure in the low pressure fuel passage;
A detection value acquisition unit for acquiring the detection value of the fuel pressure sensor at a constant sampling time interval;
A required injection amount calculation unit that calculates a required injection amount required for the port injection valve based on the state of the internal combustion engine;
An acquisition unit that acquires an end crank angle that is a crank angle corresponding to a scheduled end timing of fuel injection of the port injection valve;
A pulsation determining unit that determines whether or not the rotational speed of the internal combustion engine calculated based on the output of the crank angle sensor belongs to a pulsation increasing region where the pulsation increases compared to other rotational speed regions of the internal combustion engine. When,
A storage unit that stores an equation (2) that includes an equation (1) that models the pulsation, and that can calculate a provisional injection amount when the port injector temporarily injects fuel in an arbitrary crank angle range;
If an affirmative determination is made by the pulsation determining unit, based on the acquired end crank angle and the expression (2), a temporary crank angle from the reference crank angle corresponding to the initial phase of the pulsation to the end crank angle is determined. The value obtained by subtracting the temporary injection amount from the reference crank angle to the start crank angle that is the crank angle corresponding to the scheduled fuel injection start timing of the port injector from the injection amount is regarded as equal to the required injection amount. When the start crank angle is calculated and the pulsation determining unit makes a negative determination, the port injection valve is calculated from the acquired end crank angle, the required injection amount, and the end crank angle. The start crank angle is calculated based on the detected value acquired immediately before the crank angle that is back by the crank angle range corresponding to the maximum value that the target energization period can take. A calculation unit,
A target energization period conversion unit that converts a crank angle range from the start crank angle to the end crank angle into a target energization period;
An internal combustion engine control apparatus comprising: an injection control unit that performs fuel injection by energizing the port injection valve for the target energization period.

However, θ [deg] is the crank angle, P (θ) [kPa] is the fuel pressure value corresponding to the crank angle θ [deg], A [kPa] is the amplitude of the pulsation, and c is the high pressure per 360 degrees of the crank angle. The number of fuel discharges by the pump, B [deg] is the initial phase of the pulsation, P _c [kPa] is the central fuel pressure value of the pulsation, Q _p [mL] is the temporary injection amount, k [mL · min ⁻¹ · kPa ^−0.5 ] is a constant, and Ne [rpm] is the rotational speed of the internal combustion engine.

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