JP2018184835A - Control device of internal combustion engine and control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve exhaust performance by setting the injection finish timing of a fuel injection valve, in an internal combustion engine having the fuel injection valve for injecting fuel into an intake pipe.SOLUTION: A control device has injection finish timing setting means for setting the injection finish timing of a fuel injection valve, and command output means for outputting a valve-open command signal for finishing fuel injection at the injection finish timing. The injection finish timing setting means sets the injection finish timing to timing which is advanced as a load of the internal combustion engine becomes large in a crank angle region after an intake top dead point. A wall flow flow-in amount is reduced by the setting of the injection finish timing, and a discharge particle number PN of particulate substances is reduced.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a control device and a control method for controlling a fuel injection valve that injects fuel into an intake pipe of an internal combustion engine.

  The fuel supply control device for an internal combustion engine disclosed in Patent Document 1 supplies fuel from the fuel injection valve in synchronization with the intake stroke when the intake air amount is small, and before the intake stroke starts when the intake air amount is large. Complete the fuel supply.

JP 2002-235580 A

  By the way, when the control device that controls the fuel injection valve that injects fuel into the intake pipe of the internal combustion engine advances or retards the injection timing in accordance with the engine load, A thick liquid film of fuel is formed on the valve umbrella and the intake port wall, and after opening the intake valve, the fuel flows into the cylinder as a wall flow and adheres to the bore, and the fuel attached to the bore becomes steamed. As a result, the number of discharged particles PN of the particulate matter increases and the exhaust properties may deteriorate.

  The present invention has been made in view of conventional circumstances, and an object thereof is to provide a control device and a control method for an internal combustion engine that can improve exhaust properties by setting an injection end timing.

  According to the present invention, in one aspect thereof, the injection end timing of the fuel injection valve that injects fuel into the intake pipe of the internal combustion engine is advanced as the load on the internal combustion engine increases within the crank angle region after the intake top dead center. Set at the corner.

  According to the above invention, the exhaust properties of the internal combustion engine can be improved by optimizing the injection end timing.

1 is a system configuration diagram of an internal combustion engine in an embodiment of the present invention. It is a flowchart which shows the setting process of the injection end time in embodiment of this invention. It is a diagram which shows the correlation with the engine load and injection completion time in embodiment of this invention. It is a figure for demonstrating the condition where wall flow inflow amount increases with the excessive advance angle at the time of high load. It is a figure for demonstrating the condition where the amount of wall flow inflow increases by the excessive retardation at the time of low load. It is a diagram which shows the correlation with wall flow inflow amount at the time of low load, the number PN of discharge | emission particle | grains, and the injection end time. It is a diagram which shows the correlation with the amount of wall flow inflows at the time of high load, the number PN of discharge | emission particle | grains, and the injection end time. It is a figure which shows the table of the retardation correction value HIETD1 in embodiment of this invention. It is a figure which shows the correlation with the spray particle diameter and injection timing in embodiment of this invention. It is a diagram which shows the correlation with the number PN of discharge | emission particle | grains at the time of high load, a charging efficiency, a knock limit ignition timing, and the injection end timing. It is a diagram which shows the correlation with the fuel pressure and injection completion time in embodiment of this invention. It is a figure which shows the correlation with the fuel pressure and injection timing in embodiment of this invention. It is a diagram which shows the correlation with the spray particle diameter SMD at the time of low load, the number PN of discharge | emission particles, unburned fuel HC, and a fuel pressure setting value. It is a diagram which shows the correlation with the spray particle size SMD at the time of high load, the number PN of discharge | emission particles, unburned fuel HC, and a fuel pressure setting value.

Embodiments of a control device and a control method for an internal combustion engine according to the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing an aspect of an internal combustion engine to which a control device and a control method according to the present invention are applied.

An internal combustion engine 1 shown in FIG. 1 is a spark ignition gasoline engine for vehicles, and includes an ignition device 4, a fuel injection valve 5, and the like in an engine body 1a.
The fuel injection valve 5 injects fuel into the intake pipe 2a in the vicinity of the umbrella portion of the intake valve 19. That is, the internal combustion engine 1 shown in FIG. 1 is a so-called port injection type internal combustion engine in which the fuel injection valve 5 injects fuel into the intake pipe 2a.

The air sucked through the air cleaner 7 is adjusted in flow rate by the throttle valve 8 a of the electric throttle 8, and then mixed with the fuel injected from the fuel injection valve 5 into the intake pipe 2 a to enter the combustion chamber 10. Sucked.
The electric throttle 8 is a device that opens and closes the throttle valve 8a with a throttle motor 8b, and includes a throttle opening sensor 8c that outputs a signal corresponding to the opening TPS of the throttle valve 8a.

The rotation speed detection device 6 outputs a signal of the rotation angle NE for each predetermined rotation angle of the crankshaft 17 by detecting the protrusion of the ring gear 14.
The water temperature sensor 15 outputs a signal corresponding to the temperature of the cooling water in the water jacket 18 provided in the engine body 1a (hereinafter referred to as the water temperature TW).

The flow rate detection device 9 is disposed upstream of the electric control throttle 8 and outputs a signal corresponding to the intake air flow rate QAR of the internal combustion engine 1.
Further, the exhaust purification catalyst device 12 disposed in the exhaust pipe 3a purifies the exhaust gas of the internal combustion engine 1.

The air-fuel ratio sensor 11 is disposed in the exhaust pipe 3a on the upstream side of the exhaust purification catalyst device 12, and outputs a signal corresponding to the exhaust air-fuel ratio RABF (oxygen concentration).
The exhaust temperature sensor 16 is disposed in the exhaust pipe 3 a upstream of the exhaust purification catalyst device 12 and outputs a signal corresponding to the exhaust temperature TEX (° C.) at the inlet of the exhaust purification catalyst device 12.

Fuel is adjusted to a predetermined pressure by the fuel supply device 31 and supplied to the fuel injection valve 5.
The fuel supply device 31 includes a fuel tank 32, an electric fuel pump 33, a pressure regulator 34, a fuel supply pipe 35, a fuel return pipe 36, and a fuel pressure sensor 37.

The fuel pump 33 sucks the fuel in the fuel tank 32 and pumps the fuel to the fuel injection valve 5 through the fuel supply pipe 35. One end of the fuel return pipe 36 is connected to the middle of the fuel supply pipe 35, the other end is opened in the fuel tank 32, and a pressure regulator 34 for returning the fuel to the fuel tank 32 through an orifice is interposed.
The pressure of the fuel supplied to the fuel injection valve 5 is detected by the fuel pressure sensor 37, and the pressure of the fuel supplied to the fuel injection valve 5 is controlled by controlling the drive voltage of the fuel pump 33 according to the fuel pressure detection value by the fuel pressure sensor 37. Is set to be variable.

The control device 13 incorporating the microcomputer outputs sensor signals such as the opening degree TPS, the intake air flow rate QAR, the rotation angle NE, the water temperature TW, the exhaust air / fuel ratio RABF, the exhaust temperature TEX, and the fuel pressure PF, which are output from the various sensors described above. Capture.
Then, the control device 13 calculates a fuel injection pulse width TI (fuel injection amount) and injection timing based on the acquired sensor signal, and outputs a valve opening command signal corresponding to the fuel injection pulse width TI (ms) at the injection timing. A function (command output means) for outputting to the fuel injection valve 5 is provided.

Further, the control device 13 also outputs command signals to the ignition device 4, the electric throttle 8, and the fuel pump 33 to control the ignition timing of the ignition device 4, the opening degree of the throttle valve 8 a, and the fuel pressure of the fuel injection valve 5. Thus, the operation of the internal combustion engine 1 is controlled.
The control device 13 inputs / outputs data (measurement results of various sensors and operation amounts output to various devices), an analog input circuit 20, an A / D conversion circuit 21, a digital input circuit 22, an output circuit 23, and An I / O circuit 24 is provided.

In addition, the control device 13 includes a microcomputer including an MPU (Microprocessor Unit) 26, a ROM (Read Only Memory) 27, and a RAM (Random Access Memory) 28 in order to perform data arithmetic processing.
Sensor signals such as the intake air flow rate QAR, the opening degree TPS, the exhaust air / fuel ratio RABF, the exhaust gas temperature TEX, the water temperature TW, and the fuel pressure PF are input to the analog input circuit 20.
Various signals input to the analog input circuit 20 are respectively supplied to the A / D conversion circuit 21, converted into digital signals, and output onto the bus 25.

Further, the signal of the rotation angle NE input to the digital input circuit 22 is output on the bus 25 via the I / O circuit 24.
Connected to the bus 25 are an MPU 26, a ROM 27, a RAM 28, a timer / counter (TMR / CNT) 29, and the like. The MPU 26, ROM 27, and RAM 28 exchange data via the bus 25.

A clock signal is supplied from the clock generator 30 to the MPU 26, and the MPU 26 executes various calculations and processes in synchronization with the clock signal.
The ROM 27 is composed of, for example, an EEPROM (Electrically Erasable Programmable Read-Only Memory) capable of erasing and rewriting data, and stores a program for operating the control device 13, setting data, initial values, and the like.

Information stored in the ROM 27 is read into the RAM 28 and the MPU 26 via the bus 25.
The RAM 28 is used as a work area for temporarily storing calculation results and processing results by the MPU 26.

The timer / counter 29 is used for measuring time, measuring various times, and the like.
Calculation results and processing results by the MPU 26 are output to the bus 25 and then supplied from the output circuit 23 to the ignition device 4, the fuel injection valve 5, the electric throttle 8 and the fuel pump 33 via the I / O circuit 24. Is done.

In the control of the fuel injection valve 5, the control device 13 calculates the injection end timing IET and the fuel injection pulse width TI (ms) based on the operating conditions of the internal combustion engine 1, and further calculates the crank angle converted value of the fuel injection pulse width TI. The injection start timing IST is calculated based on the injection end timing IET.
Then, the control device 13 detects the injection start timing IST based on the signal of the rotation angle NE and outputs a valve opening command signal having the fuel injection pulse width TI to the fuel injection valve 5.
The injection end timing IET and the injection start timing IST are represented by a crank angle with the intake top dead center (intake TDC) as a reference position.

FIG. 2 is a flowchart showing the procedure of the injection end time IET setting process (function as injection end time setting means) by the control device 13.
In step S101, the control device 13 calculates the basic injection end timing IETb based on the load of the internal combustion engine 1.

Here, the control device 13 obtains the fuel injection pulse width TI, the cylinder intake air amount, the throttle opening, the intake negative pressure, and the like as state quantities indicating the load of the internal combustion engine 1, and based on these, the basic injection end timing IETb is determined. Set.
FIG. 3 is a diagram showing an aspect of the correlation between the engine load and the basic injection end timing IETb. The control device 13 calculates the basic injection end timing IETb based on the engine load according to the correlation shown in FIG.

As shown in FIG. 3, the control device 13 sets the basic injection end timing IETb to a timing that is advanced as the load of the internal combustion engine 1 becomes higher in the crank angle region after the intake top dead center.
Here, the basic injection end timing IETb is preliminarily adapted based on experiments, simulations, and the like so as to suppress an increase in the wall flow inflow amount flowing into the cylinder from the intake pipe 2a according to a load change of the internal combustion engine 1. It has been done.

  There is a place where the wall flow inflow rate changes from a decrease change to an increase change (minimum) when the injection end timing IET is changed to advance or retard under the same engine load condition. When the injection end timing IET is over-advanced and over-retarded from the injection end timing IET, the wall flow inflow amount increases. Further, the injection end timing IET at which the wall flow inflow amount becomes a minimum value is a timing that is advanced more as the engine load is higher.

  Therefore, the control device 13 performs basic injection based on the correlation between the engine load and the basic injection end timing IETb determined so as to trace the injection end timing IET where the wall flow inflow amount becomes a value near the minimum value for each engine load. The end time IETb is determined, and the injection end time IET at which the wall flow inflow amount becomes a minimum value is a more advanced time as the engine load is higher. Therefore, the basic injection end time IETb is determined by the internal combustion engine 1. It is set at a time when the angle is advanced as the load increases.

  In other words, the setting range of the injection end timing IET in which the wall flow inflow amount is in the vicinity of the minimum value, that is, the advance limit and delay limit of the injection end timing IET for suppressing the wall flow inflow amount in the vicinity of the minimum value. Is determined in advance by experiments or simulations, and the control device 13 is configured to change the basic injection end timing IETb in accordance with the engine load within the set range.

The fuel wall flow flowing into the cylinder from the intake pipe 2a adheres to the cylinder bore or the like and becomes steamed when the air-fuel mixture burns, thereby increasing the number of exhausted particles PN of the particulate matter and improving the exhaust properties of the internal combustion engine 1. It becomes a factor to worsen.
Therefore, the control device 13 controls the injection timing of the fuel injection valve 5 based on the basic injection end timing IETb, thereby reducing the inflow amount of the wall flow, that is, the number of discharged particles PN as much as possible. The exhaust property of can be improved.

Hereinafter, the correlation between the injection end timing IET and the wall flow inflow amount will be described in detail.
FIG. 4 is a diagram for explaining a situation in which the wall flow inflow increases when the internal combustion engine 1 is in a high load state. FIG. 5 illustrates a situation in which the wall flow inflow increases in the low load state of the internal combustion engine 1. It is a figure for demonstrating.

If the injection end timing IET is excessively advanced while the internal combustion engine 1 is in a high load state, more fuel is injected toward the umbrella portion of the intake valve 19 while the intake valve 19 is closed. The amount of fuel adhering to the liquid in the umbrella portion of the intake valve 19 increases and a thick liquid film is formed.
On the other hand, if the injection end timing IET is excessively retarded in a low load state of the internal combustion engine 1, the fuel injected toward the intake valve 19 while the intake valve 19 is open is deflected by the intake flow, The amount of fuel adhering to the intake port in a liquid state increases to form a thick liquid film.

As described above, the fuel that is thickly attached to the umbrella portion and the intake port of the intake valve 19 flows into the cylinder as a wall flow when the intake valve 19 is opened, and adheres to the cylinder bore and the like. The fuel adhering to the cylinder bore is in a steamed state when the air-fuel mixture burns in the combustion chamber, and this increases the number PN of discharged particles of particulate matter.
Therefore, the present inventors analyzed the correlation between the wall flow inflow amount and the number of discharged particles PN and the injection end timing IET, and obtained the characteristics of the injection end timing IET that can reduce the number of discharged particles PN as much as possible.

FIG. 6 shows the correlation between the number of discharged particles PN [N / cc] and the injection end timing IET [degATDC] and the wall flow inflow [mg] when the internal combustion engine 1 is warmed up at a low load near idling. The correlation with the injection end timing IET [degATDC] is shown.
At a low load near the idling, the wall flow inflow amount is the smallest when the injection end timing IET is approximately 30 deg to 90 deg after the intake top dead center (30 degATDC-90 degATDC), and this wall flow inflow amount is the smallest. The emission particle number PN tended to be the smallest when the injection end time IET was reached.

On the other hand, FIG. 7 shows the correlation between the number of exhaust particles PN and the injection end timing IET and the wall flow inflow amount and the injection end timing IET when the internal combustion engine 1 is operated at a high load (full load) with the throttle fully open after warming up. The correlation is shown.
When the throttle end is fully opened and the injection end timing IET is 90 degATDC in which the wall flow inflow and the number of discharged particles PN are reduced by idling, the wall flow inflow and the number of discharged particles PN are larger than in idling. The wall flow inflow and the number of discharged particles PN tended to decrease as the end time IET was advanced from 90 degATDC.

When the throttle is fully open and the injection end timing IET is advanced to 60 deg (60 deg ATDC) after intake top dead center, the wall flow inflow is suppressed to near the minimum amount at idling, and the injection end timing is further increased. When the IET is advanced to the intake top dead center (0 degATDC), the wall flow inflow becomes the smallest. In the region before the intake top dead center, the wall flow inflow increases as the injection end timing IET is advanced. Showed a trend.
Furthermore, the present inventors reduce the amount of unburned fuel (HC) discharged as the injection end timing IET approaches the intake top dead center after the intake top dead center at a high load (full load) with the throttle fully open. However, even if the injection end timing IET is set before the intake top dead center, there is no significant difference in the amount of unburned fuel (HC) emitted compared to when the injection end timing IET is set to the intake top dead center. I found.

On the other hand, the control device 13 needs to determine the fuel injection pulse width TI at an earlier time as the injection end timing IET is advanced, and the follow-up delay of the fuel injection pulse width TI with respect to the load change becomes large, so There is a possibility that an air-fuel ratio shift will occur. That is, the control response of the fuel injection pulse width TI by the control device 13 decreases as the injection end timing IET is advanced.
Thus, it can be said that the injection end timing IET before the intake top dead center does not significantly affect the reduction of unburned fuel (HC), and the injection end timing in terms of the control response of the fuel injection pulse width TI. An excessive advance of the IET is undesirable.

Therefore, if the injection end timing IET is set to 60 deg after the intake TDC (0 degATDC-60 degATDC) at a high load with the throttle fully opened, the amount of unburned fuel (HC) discharged is suppressed as much as possible. The wall flow inflow amount and the number of discharged particles PN can be reduced to the same level or less as that during idling, and a decrease in the control response of the fuel injection pulse width TI can be suppressed.
As described above, the present inventors set the injection end timing IET between 30 degATDC-90 degATDC at a low load near idling, and the injection end timing IET between 0 degATDC-60 degATDC at a high load at full throttle. As a result, the analysis result that the wall flow inflow amount and the number of discharged particles PN can be reduced as much as possible while suppressing the discharge amount of unburned fuel (HC).

Therefore, in the intermediate load region between the low load near the idling and the high load with the throttle fully opened, the setting range of the injection end timing IET is increased from the range of 30 degATDC-90 degATDC to the range of 0 degATDC-60 degATDC as the engine load increases. By gradually advancing, it is possible to reduce the wall flow inflow amount and the number of discharged particles PN as much as possible under all load conditions.
That is, in FIG. 3, the point indicating 90 degATDC which is the retard limit of the injection end timing IET at a low load near idling and the point indicating 60 degATDC which is the delay limit of the injection end timing IET at a high load with the throttle fully open. The line connecting the two lines becomes the retardation limit of the injection end timing IET that can suppress the wall flow inflow amount and the number of discharged particles PN under each load condition.

Further, in FIG. 3, the point indicating 30 degATDC which is the advance angle limit of the injection end timing IET at a low load near idling and the intake top dead center which is the advance angle limit of the injection end timing IET at a high load with the throttle fully opened. A line connecting a point indicating (0 degATDC) is an advance angle limit of the injection end timing IET under each load condition.
Then, the control device 13 advances the injection end timing IET in accordance with the increase in the engine load within the range between the retard limit of the injection end timing IET and the advance limit of the injection end timing IET. By making the angle, the wall flow inflow amount and the number of discharged particles PN can be reduced as much as possible.

In other words, the control device 13 advances the injection end timing IET in accordance with the increase in the engine load within the crank angle range from the intake TDC to ATDC 90 deg, thereby suppressing the amount of unburned fuel (HC) emission. The number of discharged particles PN due to wall flow inflow can be reduced as much as possible.
In the example shown in FIG. 3, the control device 13 sets a crank angle near the advance angle limit within a range between the retard angle limit and the advance angle limit as the basic injection end timing IETb.
However, the control device 13 is not limited to the configuration in which the crank angle near the advance angle limit is set to the basic injection end timing IETb, and the control device 13 responds to an increase in engine load within the range between the retard angle limit and the advance angle limit. Various characteristics for advancing the basic injection end timing IETb can be employed.

When the basic injection end timing IETb is set in step S101, the control device 13 proceeds to step S102, and sets the retardation correction value HIETD1 for the basic injection end timing IETb according to the spray particle diameter of the fuel injection valve 5.
The basic injection end timing IETb is a value adapted to the spray particle diameter of the reference fuel injection valve, whereas the fuel injection valve 5 having a spray particle diameter different from the reference fuel injection valve is employed. The optimum value of the injection end timing IET is different.

Therefore, the memory of the control device 13 is provided with a table that stores the retardation correction value HIETD1 for each of a plurality of different spray particle sizes (for each of a plurality of types of fuel injection valves), and the control device 13 is given from the outside. The retard correction value HIETD1 is set based on the information on the spray particle size (type of fuel injection valve).
Here, as the spray particle diameter of the fuel injection valve 5 is smaller, the fuel spray is caused to flow into the intake flow and the fuel adhering to the cylinder bore decreases. Therefore, even if the injection end timing IET is delayed, the deterioration of the number PN of exhaust particles can be suppressed. On the other hand, by delaying the injection end timing IET, the in-cylinder direct entry rate of the fuel is improved, the decrease in the combustion chamber temperature is promoted, and knocking is improved.

Therefore, the table in which the retardation correction value HIETD1 is stored for each of a plurality of different spray particle sizes is set so that the basic injection end timing IETb is delayed more as the spray particle size is smaller.
FIG. 8 shows an example of a table in which the retardation correction value HIETD1 is stored for each of a plurality of different spray particle sizes, and FIG. 9 shows an aspect of the injection end timing IET as a result of applying the retardation correction value HIETD1. Show.

  The table of retardation correction value HIETD1 shown in FIG. 8 is divided into three types of spray particle sizes of large, medium, and small, and the retardation correction value HIETD1 is set for each of the large, medium, and small spray particle sizes, and the spray particle size “small”. At this time, the retard correction value HIETD11 is the largest and the basic injection end timing IETb is corrected to the most retarded timing, and when the spray particle size is "large", the retard correction value HIETD13 is the smallest and the basic injection end timing IETb is It is corrected to the most advanced time.

  When the basic injection end timing IETb is adapted to the spray particle size “large” in the table of FIG. 8, for example, the retardation correction value HIETD13 at the spray particle size “large” is set to zero and correction is substantially performed. The retard correction value HIETD12 at the spray particle size “medium” is used to retard the basic injection end timing IETb, and the retard correction value HIETD11 at the spray particle size “small” is set to the spray particle size “medium”. The basic injection end timing IETb is set to a value that is retarded more than when “.”

  Further, when the basic injection end timing IETb is adapted to the spray particle size “medium” in the table of FIG. 8, for example, the retardation correction value HIETD12 at the spray particle size “medium” is set to zero and the correction is substantially performed. The retard correction value HIETD11 for the spray particle size “small” is used to retard the basic injection end timing IETb, and the retard correction value HIETD13 for the spray particle size “large” is the basic injection end timing IETb. Is a value that advances.

  The injection end timing IET as a result of applying the retard correction value HIETD1 is the latest in the crank angle region after the intake TDC when the spray particle size is “small” as shown in FIG. When the particle size is “large”, it becomes the fastest in the crank angle region after the intake TDC, and when the spray particle size is “medium”, the injection end timing IET at the spray particle size “small” and the spray particle size It is set to the injection end timing IET between the “large” injection end timing IET.

FIG. 10 is a diagram for explaining the effect of the process of delaying the injection end timing IET as the spray particle size is smaller, and illustrates the change in the charging efficiency and the number of discharged particles PN with respect to the injection end timing IET at a high load. To do.
As shown in FIG. 10, when the spray particle size becomes smaller, the number of discharged particles PN at the injection end timing IET after the intake top dead center is reduced, and by delaying the injection end timing IET, the direct in-cylinder rate of the fuel is increased. As a result, the reduction of the combustion chamber temperature is promoted, and as a result, the charging efficiency is improved and knocking is less likely to occur and the ignition timing can be further advanced.

Next, in step S103, the control device 13 determines whether or not the pressure of the fuel supplied to the fuel injection valve 5 to be controlled is variable, in other words, whether or not the internal combustion engine 1 has a variable fuel pressure system. Is determined.
The internal combustion engine 1 of the present embodiment is provided with a variable fuel pressure system, and the control device 13 proceeds to step S104 and corrects the retardation of the basic injection end timing IETb according to the fuel pressure set value (target fuel pressure value) in the variable fuel pressure system. Set the value HIETD2.

Here, the higher the fuel pressure set value, the smaller the spray particle size of the fuel injection valve 5, and the smaller the spray particle size of the fuel injection valve 5, the more fuel flows to the intake flow and the fuel adhering to the cylinder bore decreases. In addition, even if the injection end timing IET is delayed, the deterioration of the number of exhausted particles PN can be suppressed. On the other hand, by delaying the injection end timing IET, the in-cylinder direct injection rate of the fuel is improved and the combustion chamber temperature is lowered, and knocking is improved. Is done.
Therefore, the control device 13 sets the retard correction value HIETD2 that retards the basic injection end timing IETb as the fuel pressure set value increases, thereby improving the charging efficiency and allowing the ignition timing to be advanced more. .

11 and 12 are diagrams illustrating the difference in the injection timing depending on the fuel pressure setting value when the basic injection end timing IETb is corrected with the retard correction value HIETD2.
As shown in FIGS. 11 and 12, the control device 13 delays the injection end timing IET more in the crank angle range from the intake TDC to ATDC 90 deg when the fuel pressure set value is high than when it is low.

FIG. 13 is a diagram illustrating the difference in the spray particle size SMD, the number of exhausted particles PN, and the unburned fuel HC due to the difference in the fuel pressure setting value when the internal combustion engine 1 is warmed up at a low load near idling.
As shown in FIG. 13, when the internal combustion engine 1 is warmed up at a low load near idling, the spray particle size SMD is decreased by increasing the fuel pressure set value, and the spray particle size SMD is decreased. While the number of emitted particles PN was reduced, the decrease in the spray particle size SMD did not contribute to the improvement of the unburned fuel HC.
That is, even when the internal combustion engine 1 is warmed up at a low load near idling, if the fuel pressure set value is increased, the spray particle size SMD is reduced, and the number of discharged particles PN can be improved.

FIG. 14 exemplifies the difference in the spray particle size SMD, the number of discharged particles PN, and the unburned fuel HC depending on the difference in the fuel pressure setting value when the internal combustion engine 1 is operated at a high load (full load) with the throttle fully opened after warming up. It is a figure to do.
As shown in FIG. 14, even when the internal combustion engine 1 is operated at a high load (full load) with the throttle fully opened after warming up, the spray particle size SMD is decreased by increasing the fuel pressure set value, and the spray particle size SMD. The decrease in the number of discharged particles PN is reduced by the decrease in, while the decrease in the spray particle size SMD does not contribute to the improvement of the unburned fuel HC.
When the internal combustion engine 1 is not equipped with a variable fuel pressure system, that is, when the fuel pressure set value is fixed, the control device 13 sets the retardation correction value HIETD2 to zero in step S105 and sets the retardation correction value HIETD2. The correction of the basic injection end timing IETb by is canceled.

When the basic injection end timing IETb, the retard correction value HIETD1, and the retard correction value HIETD2 are set as described above, the control device 13 sets the basic injection end timing IETb to the retard correction value HIETD1 and the retard in step S106. The result corrected with the correction value HIETD2 is set to the final injection end timing IET (IET = IETb + HIETD1 + HIETD2).
Then, the control device 13 obtains the injection start timing IST from the injection end timing IET and the crank angle converted value of the fuel injection pulse width TI, and at the injection start timing IST, the valve opening command signal (injection pulse). Signal) is output to the fuel injection valve 5 to terminate the fuel injection by the fuel injection valve 5 at the injection end timing IET.
As described above, according to the present embodiment, the control device 13 sets the injection end timing to a timing that is advanced as the load on the internal combustion engine increases within the crank angle region after the intake top dead center. Reduce the exhaust properties of the engine, specifically the number of exhausted particles PN.

The technical ideas described in the above embodiments can be used in appropriate combination as long as no contradiction arises.
Although the contents of the present invention have been specifically described with reference to preferred embodiments, it is obvious that those skilled in the art can take various modifications based on the basic technical idea and teachings of the present invention. It is.
For example, the control device 13 performs one or both of correction of the injection end timing IET according to the spray particle diameter (type of the fuel injection valve 5) of the fuel injection valve 5 and correction of the injection end timing IET according to the fuel pressure set value. Can be omitted.

Further, the control device 13 can correct the basic injection end timing IETb set according to the engine load according to the cooling water temperature representing the temperature of the internal combustion engine 1, and more specifically, the cooling water temperature is high. The injection end timing IET can be delayed more in the crank angle range from the intake TDC to ATDC 90 deg (as the fuel spray is easily vaporized).
Further, when the internal combustion engine 1 includes a particulate matter detection sensor as disclosed in, for example, Japanese Patent Application Laid-Open No. 2017-40563, the control device 13 sets the basic injection end timing IETb set according to the engine load in a particulate form. Correction based on the particulate matter detected by the substance detection sensor, or learning processing for changing the correlation between the engine load and the basic injection end timing IETb based on the particulate matter detected by the particulate matter detection sensor can do.

Here, the technical idea that can be understood from the above-described embodiment will be described below.
An internal combustion engine control device, as one aspect thereof, is a control device that controls a fuel injection valve that injects fuel into an intake pipe of the internal combustion engine, and the control device sets an injection end timing of the fuel injection valve. Injection end timing setting means; and command output means for outputting a valve opening command signal for ending fuel injection at the injection end timing to the fuel injection valve. The injection end timing setting means includes the injection end timing Is set to a time when the load of the internal combustion engine increases within a crank angle range from intake top dead center to ATDC 90 deg.

  DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2a ... Intake pipe, 5 ... Fuel injection valve, 13 ... Control apparatus

Claims (5)

A control device for controlling a fuel injection valve for injecting fuel into an intake pipe of an internal combustion engine,
The control device includes:
Injection end timing setting means for setting an injection end timing of the fuel injection valve;
Command output means for outputting to the fuel injection valve a valve opening command signal for ending fuel injection at the injection end timing;
Have
The injection end timing setting means sets the injection end timing to a timing advanced as the load of the internal combustion engine increases within a crank angle region after intake top dead center.
Control device for internal combustion engine.   2. The control device for an internal combustion engine according to claim 1, wherein the injection end timing setting means sets the injection end timing to a timing delayed as the spray particle size of the fuel injection valve decreases.   2. The control apparatus for an internal combustion engine according to claim 1, wherein the injection end timing setting means sets the injection end timing to a timing delayed as the pressure of fuel supplied to the fuel injection valve increases. The injection end time setting means includes
Setting the injection end timing so as to suppress an increase in the wall flow inflow amount flowing into the cylinder from the intake pipe according to a load change of the internal combustion engine;
The control device for an internal combustion engine according to any one of claims 1 to 3. A control method for controlling a fuel injection valve for injecting fuel into an intake pipe of an internal combustion engine,
Detecting a load of the internal combustion engine;
Setting the injection end timing to a timing advanced as the load of the internal combustion engine becomes higher in a crank angle region after intake top dead center;
Outputting a valve opening command signal for ending fuel injection at the injection end timing to the fuel injection valve;
A control method for an internal combustion engine, comprising: