Internal combustion engine control device and internal combustion engine control method

Abstract

To provide an internal combustion engine control device and an internal combustion engine control method capable of preventing variation of an injection amount due to fluctuation of a fuel pressure that causes deterioration of exhaust gas and fuel economy of an internal combustion engine without increasing a calculation load.SOLUTION: An internal combustion engine control device includes a fuel injection control planning section and a pressure value acquisition section. The pressure value acquisition section acquires a first fuel pressure value 60, a second fuel pressure value 61 and a calculation fuel pressure value 62. The first fuel pressure value 60 is acquired in a first period from pressurization operation timing of a fuel pump to injection of fuel from a fuel injection valve for the first time since the pressurization operation timing. The second fuel pressure value 61 is acquired in a second period that is a period up to pressurization timing after the first period. The calculation fuel pressure value 62 is calculated on the basis of the first fuel pressure value 61 and the second fuel pressure value 62. The fuel injection control planning section selects at least one type or more of pressure values from the first fuel pressure value 60, the second fuel pressure value 61 and the calculation fuel pressure value 62, and in accordance with the selected pressure values, corrects a control amount of the fuel injection valve.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an internal combustion engine control device and an internal combustion engine control method. [Background technology]

[0002] A pressure-accumulating (common rail) fuel injection control device is known as a device for supplying fuel to multiple cylinders of a vehicle engine. This device accumulates pressurized fuel in a fuel supply pipe using a high-pressure fuel pump or the like, and injects the fuel through a fuel injection valve installed in the fuel pipe. The internal combustion engine control device controls the fuel pressure accumulated in the fuel pipe and the fuel injection amount by the injection valve to desired values ​​according to the operating state of the internal combustion engine. For this control, it is known to use, for example, pressure values ​​sampled at a predetermined interval by a pressure sensor.

[0003] When using the above-mentioned accumulator-type fuel injection control, fuel pressure in the fuel pipe fluctuates constantly due to the supply (discharge) from the high-pressure fuel pump to the fuel pipe and the fuel injection from the fuel injector. In particular, there is concern about increased fuel pressure fluctuations when performing high-speed split injection, which is common in many internal combustion engines these days. Meanwhile, the pressure sampling method described above may not be able to capture these fluctuations sequentially, raising concerns that fuel pressure fluctuations may directly affect the fuel injection amount. This could change the mixture of air and fuel supplied to the engine, potentially resulting in poor emissions and poor fuel economy.

[0004] To solve such problems, a technique such as that described in Patent Document 1 has been disclosed. Patent Document 1 describes a technique that calculates a change in fuel pressure during fuel injection and corrects the fuel injection pulse width based on the amount of fuel pressure change and the fuel pressure at the start of injection. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-38857 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the technology described in Patent Document 1, in order to obtain the change in fuel pressure (fuel pressure fluctuation) during fuel injection, it is necessary to perform sequential calculations using the fuel pump discharge amount and the fuel injection amount of the fuel injection valve based on the fuel pressure sampled by the pressure sensor at the start of fuel injection. As a result, the technology described in Patent Document 1 has the problem of increasing the calculation load and the number of calculations. In particular, when performing high-speed split injection, the technology described in Patent Document 1 is not preferable from the viewpoint of implementation.

[0007] In consideration of the above problems, an object of the present invention is to provide an internal combustion engine control device and an internal combustion engine control method that can prevent injection amount variations due to fuel pressure fluctuations, which are a cause of exhaust emissions and deterioration of fuel efficiency of an internal combustion engine, without increasing the calculation load. [Means for solving the problem]

[0008] In order to solve the above problems, for example, the configurations described in the claims are adopted. The present application includes multiple means for solving the above problems, and as an example, an internal combustion engine control device of the present invention is an internal combustion engine control device for controlling an internal combustion engine equipped with a reciprocating fuel pump that intermittently pressurizes fuel and discharges it into a fuel pipe, and a fuel injection valve that injects the intermittently pressurized fuel. The internal combustion engine control device also includes a fuel injection control planning unit that plans control details related to the opening or closing of the fuel injection valve depending on the operating state of the internal combustion engine, and a pressure value acquisition unit that acquires pressure values ​​from a pressure sensor provided in the internal combustion engine. The pressure value acquisition unit acquires a first fuel pressure value, a second fuel pressure value, and a calculated fuel pressure value. The first fuel pressure value is acquired during a first period from the pressurizing operation timing of the fuel pump until the first injection of fuel from the fuel injector thereafter. The second fuel pressure value is acquired during a second period following the first period until the pressurizing operation timing. The calculated fuel pressure value is calculated using the first fuel pressure value and the second fuel pressure value. The fuel injection control planning unit selects at least one pressure value from the first fuel pressure value, the second fuel pressure value, and the calculated fuel pressure value, and corrects the control amount of the fuel injector according to the selected pressure value.

[0009] Furthermore, an internal combustion engine control method of the present invention is a method for controlling an internal combustion engine equipped with a reciprocating fuel pump that intermittently pressurizes fuel and discharges it into a fuel pipe, and a fuel injection valve that injects the intermittently pressurized fuel, and includes the following processes (1) to (4): (1) A process of acquiring the first fuel pressure value during a first period from the timing of the pressurizing operation of the fuel pump to the time when fuel is first injected from the fuel injection valve after that. (2) A process of acquiring a second fuel pressure value acquired in a second period that is a period from the first period until the pressurization timing. (3) A process of calculating a calculated fuel pressure value using the first fuel pressure value and the second fuel pressure value. (4) A process of selecting at least one pressure value from the first fuel pressure value, the second fuel pressure value, and the calculated fuel pressure value, and correcting the control amount of the fuel injector according to the selected pressure value. [Effects of the Invention]

[0010] According to the internal combustion engine control device and the internal combustion engine control method configured as described above, it is possible to prevent variations in the injection amount due to fuel pressure fluctuations, which are a cause of exhaust emissions and deterioration of fuel efficiency of an internal combustion engine, without increasing the calculation load. Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is an overall configuration diagram of a fuel injection device controlled by an internal combustion engine device according to an embodiment; [Figure 2] 4 is a time chart showing an example of conventional fuel injection control. [Figure 3] 4 is a time chart showing a first operation example in fuel injection control of the internal combustion engine control device according to the embodiment. [Figure 4] 4 is a flowchart showing a first operation example of fuel injection control of the internal combustion engine control device according to the embodiment. [Figure 5] 4 is a time chart showing an example of a method for acquiring a pressure value in the internal combustion engine control device according to the embodiment. [Figure 6] 5 is a time chart showing a second operation example in fuel injection control of the internal combustion engine control device according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of an internal combustion engine control device and an internal combustion engine control method will be described with reference to Figures 1 to 6. Note that common members in the figures are given the same reference numerals.

[0013] 1. Example of implementation 1-1. Example of fuel injection system configuration First, an example of the configuration of a fuel injection device controlled by an internal combustion engine control device according to an embodiment (hereinafter referred to as "this example") will be described with reference to FIG. FIG. 1 is a diagram showing the overall configuration of a fuel injection device controlled by an internal combustion engine control device.

[0014] The internal combustion engine control device according to this example is a control device for controlling a four-stroke engine that repeats four strokes: an intake stroke, a compression stroke, a combustion (expansion) stroke, and an exhaust stroke. This internal combustion engine is, for example, a multi-cylinder engine having four cylinders. Note that the number of cylinders that the internal combustion engine has is not limited to four, and it may have three or six or more cylinders.

[0015] An internal combustion engine is equipped with a fuel injection device 1 that injects fuel into cylinders. As shown in Fig. 1, the fuel injection device 1 includes a feed pump 2, a high-pressure fuel pump 3, a common rail 4, injectors 10 representing fuel injection valves, and an internal combustion engine control device (ECU: Engine Control Unit) 7. The fuel injection device 1 injects and supplies fuel to each cylinder of the internal combustion engine 9 at appropriate timing.

[0016] The fuel injection device 1 also draws fuel from a fuel tank 50 via a feed pump 2. The feed pump 2 and a high-pressure fuel pump 3 are connected via a low-pressure pipe 8. A plunger 13 is slidably held in the high-pressure fuel pump 3. The high-pressure fuel pump 3 also has a discharge valve 11, a pressurizing chamber 12, and an intake valve unit 30.

[0017] The intake valve unit 30 is connected to the low-pressure pipe 8 and draws in fuel through the low-pressure pipe 8. The solenoid-type intake valve unit 30 is also connected to the pressurizing chamber 12. The pressurizing chamber 12 is also connected to the discharge valve 11.

[0018] One end of the plunger 13 is inserted into the pressurizing chamber 12 and increases or decreases the volume of the pressurizing chamber 12. The other end of the plunger 13 abuts against a cam 5 attached to the shaft of the internal combustion engine 9. The plunger 13 reciprocates within the high-pressure fuel pump 3 as the cam 5 is driven to rotate. This reciprocating motion of the plunger 13 causes the volume of the pressurizing chamber 12 to expand and contract.

[0019] Here, the cam 5 is attached to a shaft that drives an intake valve or an exhaust valve (not shown) of the internal combustion engine 9. The shaft receives power via a variable valve mechanism 40. Therefore, when the variable valve mechanism 40 is driven, a difference occurs in phase between the internal combustion engine 9 and the high-pressure fuel pump 3.

[0020] A high-pressure pipe 14 is connected to the discharge valve 11 of the high-pressure fuel pump 3. A common rail 4 is connected to the high-pressure pipe 14. The common rail 4 constitutes a high-pressure fuel path that communicates with the discharge port of the high-pressure fuel pump 3. The common rail 4 is a pressure accumulator that accumulates the fuel pumped from the high-pressure fuel pump 3 and maintains the fuel pressure at a predetermined pressure that corresponds to the operating state of the internal combustion engine 9. Injectors 10 are connected to the common rail 4 in accordance with the intake of each cylinder of the internal combustion engine 9. The injectors 10 inject the fuel supplied via the common rail 4 into each cylinder of the internal combustion engine 9. The injectors 10 are equipped with solenoid-type direct-acting actuators. An opening and closing valve of each injector 10 is controlled by the duration of current flow to the solenoid.

[0021] As described above, in the high-pressure fuel pump 3, the plunger 13 is driven up and down by the cam 5. This causes the volume of the pressurization chamber 12 to expand and contract, thereby drawing in and pressurizing the fuel and supplying it to the discharge valve 11. When the pressure in the pressurization chamber 12 becomes higher than the pressure filling the high-pressure pipe 14 and the common rail 4, the discharge valve 11 opens and pressure-feeds the fuel to the high-pressure pipe 14 and the common rail 4.

[0022] When the plunger 13 moves from the top dead center toward the bottom dead center, the volume of the pressurizing chamber 12 expands. As a result, fuel supplied from the feed pump 2 is drawn into the pressurizing chamber 12. If the intake valve is open when the plunger 13 moves from the bottom dead center toward the top dead center, the fuel in the pressurizing chamber 12 flows back toward the fuel tank 50 through the low-pressure pipe 8.

[0023] If the intake valve is closed when the plunger 13 moves from the bottom dead center to the top dead center, the fuel remaining in the pressurizing chamber 12 begins to be pressurized. When the pressure becomes higher than the pressure in the common rail 4, the discharge valve 11 opens and the fuel is pumped out.

[0024] 1-2. Configuration example of an internal combustion engine control device The ECU 7 has a CPU that performs calculations according to a predetermined program and controls each device, memory areas such as RAM and ROM that record programs, data, and calculation results, an interface for inputting and outputting signals, etc. The ECU 7 is also connected to the pressure sensor 6, crank angle sensor 15, accelerator opening sensor 16, etc., and receives signals detected by each sensor.

[0025] Here, the pressure sensor 6 detects the pressure in the common rail 4. The crank angle sensor 15 detects the crank angle. The accelerator opening sensor 16 detects the opening of the accelerator.

[0026] The ECU 7 detects the operating state of the internal combustion engine 9 based on the detection signals of each sensor. The ECU 7 then controls the energization of the intake valve unit 30 provided on the intake side of the high-pressure fuel pump 3. In this way, the ECU 7 controls the discharge amount of the high-pressure fuel pump 3 and controls the discharge pressure. Furthermore, the ECU 7 controls the injection pulse width Ti(n) of the injector 10 of each cylinder, thereby controlling the amount of fuel supplied to the internal combustion engine 9. Note that n represents the cylinder number.

[0027] The ECU 7 also has a pressure value acquisition unit 64 and a fuel injection control planning unit 63 (see FIG. 4). The pressure value acquisition unit 64 acquires a first fuel pressure value (first pressure) 60 and a second fuel pressure value (second pressure) 61 (described later) based on the detection value input from the pressure sensor 6. The pressure value acquisition unit 64 calculates a calculated fuel pressure value (calculated pressure) 62 from the first fuel pressure value (first pressure) 60 and the second fuel pressure value (second pressure) 61. The fuel injection control planning unit 63 then plans control details related to the opening or closing of the injector 10 according to the operating state of the internal combustion engine 9, and corrects the control amount of the injector 10. For example, the fuel injection control planning unit 63 selects one or more pressure values ​​from a plurality of fuel pressure values ​​as the injection pressure. The fuel injection control planning unit 63 also corrects control amounts such as the injection pulse width Ti and the operation timing of the injector 10 according to the selected pressure value.

[0028] 2. Example of fuel injection control operation Next, an example of the operation of fuel injection control will be described with reference to FIGS.

[0029] 2-1. Conventional operation example First, an example of the operation of conventional fuel injection control will be described with reference to FIG. Fig. 2 is a time chart showing an example of control by a conventional injection control device. Note that the example shown in Fig. 2 shows an example in which three-stage (three times) multi-injection is performed during the intake stroke of the combustion cycle of the internal combustion engine 9.

[0030] As shown in Fig. 2, the common rail pressure shown at the bottom of the figure rises at a certain timing due to pressurization by the high-pressure fuel pump 3. After that, when an injection pulse is input to the injector 10, fuel is injected, and the common rail pressure decreases with each injection. Then, in the next cycle, the pressure rises again due to pressurization by the high-pressure fuel pump 3. This repetition causes periodic fuel pressure fluctuations in the fuel cycle.

[0031] The pressurization timing of the high-pressure fuel pump 3 changes independently of the combustion cycle mainly for the following two reasons. The first reason is that the pressurization timing varies in accordance with the timing of energization of the intake valve unit 30. The second reason is that the high-pressure fuel pump 3 itself receives driving force from the shaft via the variable valve mechanism 40, causing the operating phase to vary.

[0032] In a conventional control operation example, a representative fuel pressure value (hereinafter referred to as the "representative pressure") is obtained from a pressure sensor 6 provided in a fuel pipe in response to the fluctuating fuel pressure. The representative pressure is calculated, for example, from pressure values ​​sampled at a predetermined period or from the average value of the sampled pressure values. The conventional ECU then uses this representative pressure as the injection pressure and corrects the injection pulse width Ti of the injector 10 so as to obtain the required injection amount.

[0033] However, as shown in Figure 2, the fuel pressure at the actual injection timing may deviate from the representative pressure. In this case, a deviation occurs between the actual injection amount and the required injection amount. This changes the mixture of air and fuel supplied to the internal combustion engine, which may cause a deterioration in exhaust emissions and fuel efficiency. In the example shown in Figure 2, the first of the three injection stages is injected at a fuel pressure higher than the representative pressure, resulting in an excessive injection amount, while the third injection stage is injected at a fuel pressure lower than the representative pressure, resulting in an insufficient injection amount.

[0034] 2-2. First operation example of this example Next, a first operation example of the fuel injection control of this embodiment will be described with reference to FIGS. FIG. 3 is a time chart showing a first operation example of the fuel injection control of this embodiment.

[0035] As shown in FIG. 3, in a first operation example of this embodiment, the pressure value acquisition unit 64 of the ECU 7 acquires the higher side of the aforementioned fuel pressure fluctuation range as a first fuel pressure value (first pressure) 60 and the lower side as a second fuel pressure value (second pressure) 61. The first pressure 60 and the second pressure 61 are acquired by sampling the pressure sensor 6 at a predetermined cycle, similar to the representative pressure shown in FIG. 2. Then, the pressure value acquisition unit 64 of the ECU 7 sets the higher side of the sampled pressure values ​​as the first pressure 60 and the lower side as the second pressure 61. Note that the first pressure 60 and the second pressure 61 are set based on pressure values ​​acquired in a cycle before injection control is performed.

[0036] Here, assuming that the acquisition periods of the first pressure 60 and the second pressure 61 are the first period and the second period, the first period is the period from the pressurizing operation timing (pressurizing timing) of the high-pressure fuel pump 3 to the timing when the injector 10 first injects fuel after that. The second period is the period from the previous injection timing to the next pressurizing timing.

[0037] Next, a pressure value acquisition unit 64 of the ECU 7 calculates a calculated fuel pressure value (calculated pressure) 62 from the two acquired pressure values. For example, in a conventional control operation example, if the representative pressure is a pressure value sampled at a period independent of the combustion cycle, there is a possibility that the value may not necessarily capture the median of the fuel pressure fluctuations. Even in this case, by setting the average or median of the first pressure 60 and the second pressure 61 as the calculated pressure 62, it is possible to accurately capture the median of the fuel pressure fluctuations. Then, the pressure value acquisition unit 64 outputs the first pressure 60, the second pressure 61, and the calculated pressure 62 to a fuel injection control planning unit 63.

[0038] This allows the fuel injection control planning unit 63 of the ECU 7 to acquire multiple pressure values, namely, the first pressure 60, the second pressure 61, and the calculated pressure 62. The fuel injection timing planning unit 63 then selects, from the multiple pressure values, which pressure value is closest to the injection pressure when a subsequent injection is performed. The fuel injection control planning unit 63 then corrects the injection pulse width Ti according to the selected pressure value.

[0039] The pressure value is selected using the correspondence relationship between the injection timing and pressurization timing of the injection to be corrected. Specifically, as shown in Figure 3, first pressure 60 is selected for the first-stage injection, which is the first injection after the pressurization timing. Then, calculated pressure 62 is selected for the second-stage injection, which begins after the fuel pressure has dropped following the first-stage injection. Second pressure 61 is selected for the third-stage injection, which begins after the fuel pressure has dropped again.

[0040] As a result, in this fuel injection operation example, the injection pulse width is corrected such that the first-stage pulse width < the second-stage pulse width < the third-stage pulse width, thereby reducing the variation in the injection amount due to fuel pressure fluctuations. Note that if there is little time between the cycle in which the pressure value is acquired and the injection timing at which the correction is reflected, the injection pulse width for the next cycle may be corrected, for example, using the pressure value acquired in the previous cycle.

[0041] [Operation flow of the first operation example] Next, the operation flow of the first operation example will be described with reference to FIG. FIG. 4 is a flowchart showing a first operation example of the fuel injection control of the internal combustion engine control device of this embodiment.

[0042] 4, first, the ECU 7 calculates the pressurization timing of the high-pressure fuel pump 3 according to the operating state of the internal combustion engine 9 and other factors (step S10). Next, the fuel injection control planning unit 63 of the ECU 7 calculates the injection timing (control content) of the injector 10 according to the operating state and other factors (step S21).

[0043] Thereafter, the ECU 7 acquires a first fuel pressure value (first pressure) 60 using the pressure value acquisition unit 64 (step S30). The ECU 7 also acquires a second fuel pressure value (second pressure) 61 using the pressure value acquisition unit 64 (step S31). Then, the pressure value acquisition unit 64 calculates a calculated fuel pressure value (calculated pressure) 62 based on the acquired first pressure 60 and second pressure 61 (step S32).

[0044] Next, the fuel injection control planning unit 63 selects a pressure value that is close to the actual injection pressure from the multiple pressure values ​​of the first pressure 60, the second pressure 61, and the calculated pressure 62 (step S40). The actual injection pressure in step S40 is determined using data that is measured in advance and stored in the storage unit of the ECU 7.

[0045] Then, the fuel injection control planning unit 63 calculates a correction value for the injection pulse width Ti based on the selected pressure value (step S41). Next, the fuel injection control planning unit 63 outputs a control signal to the injector 10 so that the calculated corrected injection pulse width Ti is achieved (step S42). This completes the first operation example of fuel injection control by the internal combustion engine control device of this example.

[0046] In this example, the pressure values ​​acquired and calculated by the pressure value acquisition unit 64 and selected by the fuel injection control planning unit 63 are three pressure values, namely, the first pressure 60, the second pressure 61, and the calculated pressure 62. However, the present invention is not limited to this. For example, the pressure value acquisition unit 64 may further calculate a median value between the first pressure 60 and the calculated pressure 62 and a median value between the second pressure 61 and the calculated pressure 62, and the fuel injection control planning unit 63 may select a predetermined pressure value from the five pressure values. In this way, the pressure value calculated by the pressure value acquisition unit 64 is not limited to one, and two or more pressure values ​​may be calculated. It is preferable that the number of pressure values ​​acquired and calculated by the pressure value acquisition unit 64 be set according to the number of stages at which fuel is injected.

[0047] 2-3. How to obtain pressure values Next, an example of a method for acquiring a pressure value will be described with reference to FIG. FIG. 5 is a time chart showing an example of a method for acquiring a pressure value.

[0048] In the above explanation, only the fuel pressure fluctuations due to pressurization by the high-pressure fuel pump 3 and injection by the injector 10 have been described. However, it is believed that the actual pressure waveform includes high-frequency pulsation, as shown in Figure 5. One of the causes of high-frequency pulsation is thought to be submerged resonance in the piping system consisting of the high-pressure piping 14 and the common rail 4. Therefore, if the first pressure 60 and the second pressure 61 are sampled randomly, there is a possibility that fluctuations due to high-frequency pulsation will be sampled.

[0049] In contrast, the pressure value acquisition unit 64 of this example performs sampling multiple times during each period, for example, over a time longer than the cycle of the high-frequency pulsation. The pressure value acquisition unit 64 then performs averaging on the sampled pressure values ​​to acquire the first pressure 60 and the second pressure 61. Furthermore, the pressure value acquisition unit 64 may perform sampling over multiple cycles formed by pressurization and ejection, and then perform averaging to obtain each pressure value. This allows the first pressure 60 and the second pressure 61 to be accurately acquired without being affected by fluctuations in the high-frequency pulsation.

[0050] In this way, the internal combustion engine control device of this embodiment can prevent variations in injection amount due to fluctuations in fuel pressure without increasing the calculation load.

[0051] 2-4. Second operation example of this example Next, a second operation example of the fuel injection control of this embodiment will be described with reference to FIG. FIG. 6 is a time chart showing a second operation example of the fuel injection control of this embodiment.

[0052] In recent years, there has been a trend toward an increasing number of internal combustion engines that inject fuel in separate injectors over multiple combustion strokes in order to improve combustion. The second operation example shown in Fig. 6 is applied to a case in which fuel is injected in separate injectors, a main injection that injects more than half of the required injection amount determined according to the operating state of the internal combustion engine 9, and a sub-injection that injects a smaller amount.

[0053] As shown in Fig. 6, in addition to the main injection during the intake stroke of the internal combustion engine 9, a small amount of auxiliary injection is performed during the compression stroke. As a result, there are two possible fuel pressure fluctuations depending on the pressurization timing of the high-pressure fuel pump 3 and the injection timing of the injector 10: Case 1, where there is no pressurization timing between the main injection and the auxiliary injection, and Case 2, where there is pressurization timing.

[0054] In this case, it is preferable to select the pressure value depending on whether the secondary injection is performed in the first period or the second period shown in the first operation example. Specifically, as shown in Fig. 6, in case 1 where pressurization timing is not included (the case shown by the solid line in Fig. 6), the first pressure 60 is selected as the pressure value during secondary injection. Also, in case 2 where pressurization timing is included (the case shown by the dashed-dotted line in Fig. 6), the second pressure 61 is selected as the pressure value during secondary injection. Then, the fuel injection control planning unit 63 corrects the injection pulse width Ti according to the selected pressure value.

[0055] As a result, an injection pulse width correction is performed such that the secondary injection pulse width in Case 1 is greater than the secondary injection pulse width in Case 2. This makes it possible to reduce the injection quantity variation of the secondary injection caused by fuel pressure fluctuations. Furthermore, because the majority of the required injection quantity is injected by the main injection, it is considered that the overall fuel pressure fluctuation is dominated by the main injection. This makes it possible to apply a method similar to that of the first operation example to correct the main injection, and it is also possible to reduce the injection quantity variation of the main injection.

[0056] In this way, in the second operation example in which auxiliary injection is performed, as in the first operation example, it is possible to prevent variations in the injection amount due to fluctuations in fuel pressure without increasing the calculation load.

[0057] The present invention is not limited to the embodiments described above and shown in the drawings, and various modifications can be made within the scope of the invention as set forth in the claims.

[0058] For example, the above-described embodiments have described the configurations of the devices and systems in detail and specifically in order to clearly explain the present invention, and are not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of the embodiments described here with the configuration of other embodiments, and it is also possible to add the configuration of one embodiment to the configuration of another embodiment. Furthermore, it is also possible to add, delete, or replace part of the configuration of one embodiment with other configurations. [Explanation of symbols]

[0059] 1...Fuel injection device, 2...Feed pump, 3...High-pressure fuel pump, 4...Common rail, 5...Cam, 6...Pressure sensor, 7...ECU (internal combustion engine control unit), 8...Low-pressure piping, 9...Internal combustion engine, 10...Injector, 11...Discharge valve, 12...Pressure chamber, 13...Plunger, 14...High-pressure piping, 15...Crank angle sensor, 16...Accelerator opening sensor, 30...Intake valve unit, 40...Variable valve mechanism, 50...Fuel tank, 60...First fuel pressure value (first pressure), 61...Second fuel pressure value (second pressure), 62...Calculated fuel pressure value (calculated pressure), 63...Fuel injection control planning unit, 64...Pressure value acquisition unit

Claims

1. 1. An internal combustion engine control device for controlling an internal combustion engine including a reciprocating fuel pump that intermittently pressurizes fuel and discharges it into a fuel pipe, and a fuel injection valve that injects the intermittently pressurized fuel, a fuel injection control planning unit that plans control details relating to opening or closing of the fuel injection valve in accordance with an operating state of the internal combustion engine; a pressure value acquisition unit that acquires a pressure value from a pressure sensor provided in the internal combustion engine, The pressure value acquisition unit a first fuel pressure value acquired during a first period from the timing of the pressurizing operation of the fuel pump to the timing at which fuel is first injected from the fuel injection valve thereafter; and a second fuel pressure value acquired during a second period following the first period and ending at a pressurization timing; and obtaining a calculated fuel pressure value calculated using the first fuel pressure value and the second fuel pressure value; The fuel injection control planning unit selects at least one pressure value from the first fuel pressure value, the second fuel pressure value, and the calculated fuel pressure value, and corrects a control amount of the fuel injection valve according to the selected pressure value. Internal combustion engine control device.

2. The pressure value acquisition unit calculating the first fuel pressure value from an average value of a plurality of fuel pressure values ​​acquired during the first period; The second fuel pressure value is calculated from an average value of the plurality of fuel pressure values ​​acquired during the second period. The internal combustion engine control device according to claim 1.

3. The pressure value acquisition unit calculating the first fuel pressure value from an average of a plurality of fuel pressure values ​​acquired during a plurality of first periods across a plurality of strokes of the internal combustion engine; calculating the second fuel pressure value from an average of a plurality of fuel pressure values ​​acquired during a plurality of second periods across a plurality of strokes of the internal combustion engine; 3. The internal combustion engine control device according to claim 2.

4. The calculated fuel pressure value is an average value of the first fuel pressure value and the second fuel pressure value. The internal combustion engine control device according to claim 1.

5. At a first injection timing of the fuel injection valve, a main injection is performed in which a majority of a required injection amount determined according to an operating state of the internal combustion engine is injected, and at a second injection timing performed after the first injection timing, a sub-injection is performed in which an amount smaller than the main injection is injected, The fuel injection control planning unit when the execution of the secondary injection is scheduled in the first period, correcting a control amount of the fuel injection valve for the secondary injection based on the first fuel pressure value; When the execution of the secondary injection is scheduled in the second period, a control amount of the fuel injection valve for the secondary injection is corrected based on the second fuel pressure value. The internal combustion engine control device according to claim 1.

6. 1. A method for controlling an internal combustion engine including a reciprocating fuel pump that intermittently pressurizes fuel and discharges it into a fuel pipe, and a fuel injection valve that injects the intermittently pressurized fuel, comprising: a process of acquiring the first fuel pressure value during a first period from a pressurizing operation timing of the fuel pump to a time when fuel is first injected from the fuel injection valve after the pressurizing operation timing of the fuel pump; a process of acquiring the second fuel pressure value acquired during a second period that is a period from the first period to a pressurization timing; a process of calculating a calculated fuel pressure value using the first fuel pressure value and the second fuel pressure value; a process of selecting at least one pressure value from the first fuel pressure value, the second fuel pressure value, and the calculated fuel pressure value, and correcting a control amount of the fuel injection valve in accordance with the selected pressure value; An internal combustion engine control method comprising:

Images