JPH0693915A - Accumulative fuel injection control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To improve the accuracy of fuel injection amount controlling in a transient condition by providing a transient condition detection means which detects a transient condition of an engine and an injection pressure correction means which corrects an injection pressure value to be adapted to computation through an instantaneous fluctuation amount of the injection pressure. CONSTITUTION:Operation of an injection controlling solenoid valve 3 and a high-pressure pumping valve of a discharge rate control device 10 is controlled according to control signals output from an electronic control unit(ECU) 11. Detection signals are input from the ECU 11 from an engine speed sensor and an accelerator opening sensor 13. In the ECU 11, a detection timing for fuel injection pressure is synchronized to a crank angle of an engine, and a transient condition of the engine is detected. An instantaneous injection pressure fluctuation rate is computed according to a clamp angle of the fuel injection pressure, and an injection pressure value adapted to computation of a fuel injection engine is corrected through the instantaneous fluctuation rate of the injection pressure. Gas exhaust performance can be improved, accordingly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure accumulation type fuel injection control device for an internal combustion engine, and more particularly to a pressure accumulation type fuel injection control device for an internal combustion engine capable of improving the accuracy of fuel injection amount control in a transient state. .

[0002]

2. Description of the Related Art In a high-pressure fuel injection type internal combustion engine such as a diesel engine, a system consisting of a mechanical fuel injection pump and a fuel injection nozzle has been used in the past. A high-pressure fuel injection system has been proposed, and, for example, Japanese Patent Application Laid-Open No. 62-258160 discloses a configuration and control method of a pressure accumulating unit injector having a pressure accumulating pipe (common rail).

Among them, FIG. 9 is a block diagram showing a control method of the fuel injection amount and the fuel injection pressure (hereinafter referred to as common rail pressure). As shown in FIG. 9, the target injection amount is calculated by the target injection amount calculation circuit 91 based on the actual engine speed and the accelerator opening, and the target common rail pressure is calculated based on the calculated target injection amount and the actual engine speed. It is calculated by the target common rail pressure calculation circuit 92. Then, a comparison circuit 93 for comparing the target common rail pressure with an actual common rail pressure described later.
The high pressure pump valve energization timing calculation circuit 94 calculates the energization time based on the comparison result in FIG.
5 drives a high-pressure pump valve that opens and closes an intake port of a high-pressure pump that pressure-feeds fuel to a common rail. The common rail pressure after driving the high-pressure pump valve is detected by the actual common rail pressure detection circuit 96, and this actual common rail pressure is calculated by the comparison circuit 93 and the injector energization time calculation circuit 97.
Entered in. In this way, the high-pressure pump valve responds to the deviation between the actual common rail pressure and the target common rail pressure according to the comparison circuit 9
3, high pressure pump valve energization timing calculation circuit 94, and high pressure pump valve drive circuit 95 PID control (proportional, integral,
Differential control).

On the other hand, in the fuel injection amount control, the optimum energization time to the injector is calculated by the injector energization time calculation circuit 97 based on the target fuel injection amount and the actual common rail pressure, and a command pulse is output to the injector drive circuit 98. Then, fuel injection is performed. However, if the sampling of the above-mentioned actual common rail pressure detection is performed by time synchronization at fixed time intervals, the following problems occur. The contents will be described with reference to FIG.

FIG. 10 shows a transient state in which the engine has changed from a certain state to a certain state. Due to the state change,
The target injection amount QFIN and the target common rail pressure PFIN change stepwise. However, the actual common rail pressure NPC changes as shown by the solid line with respect to the target common rail pressure PFIN shown by the broken line, because the tracking of the change in the target injection amount QFIN is delayed, no matter how much the PID control is performed. In such a case, if the sampling of the actual common rail pressure NPC is performed in a time-synchronized manner at regular intervals, as described above, the search data necessary to inject in the i-cylinder will be QFIN1 and NPC2, for example. However, since the actual common rail pressure actually required for the i-cylinder is NPC1, a lower common rail pressure than the actual one is given as the actual common rail pressure, and an error occurs.

As described above, the fuel injection amount is the target injection amount QF.
Determined by IN and actual common rail pressure NPC,
Even if the target injection amount QFIN1 is the same, there is a difference in the energization time TQ to the injector when the actual common rail pressure NPC is NPC1 and NPC2. That is, the same target injection amount QF
The injector energization time TQ ₂ given by the actual common rail pressure NPC2 with respect to IN1 is equal to the actual common rail pressure NPC.
The injector energization time given by PC1 becomes longer than TQ ₁ , and as shown in FIGS. 11 (a) and 11 (b), more injection is performed than the injection amount actually required for the i-cylinder.
As a result, the injection amount control accuracy deteriorates, and black smoke is generated during a transition, which adversely affects exhaust gas performance.

[0007]

Therefore, in order to solve such a problem, the actual common rail pressure is sampled at regular time intervals, and the difference between the previous actual common rail pressure and the present actual common rail pressure is calculated as the actual real time. The expected control of the actual common rail pressure is performed by adding to the common rail pressure,
It is possible to control the discharge amount of the high-pressure pump valve.

However, in such an apparatus, if the sampling of the actual common rail pressure detection is time-synchronized,
The difference between the sampling timing and the injection timing may change as the engine speed increases, and even if the common rail pressure is estimated, the result of this estimated control may not be reflected in the cylinder to be injected next. There is a fear that there is.

In view of the above, the present invention solves the problems in the conventional pressure-accumulation type fuel injection control device for an internal combustion engine, avoids complication of the program, is as simple as possible, and is the correct fuel even when the internal combustion engine is in a transient state. An object of the present invention is to provide a pressure accumulation type fuel injection control device for an internal combustion engine, which can calculate an injection amount and can improve exhaust gas performance.

[0010]

A pressure-accumulation type fuel injection control system for an internal combustion engine according to the present invention which achieves the above object, detects a value of an engine operating condition parameter such as an engine speed, an accelerator opening degree and the like, and terminates a previous injection. Based on the detected value of the injection pressure of the cylinder, the command fuel injection amount, the fuel injection timing, and the command value of the injection pressure of the cylinder in which the fuel is injected next are calculated according to a predetermined program, and the injection pressure command value of the next cylinder is calculated. In a pressure-accumulation type fuel injection control device for an internal combustion engine that injects fuel in a fuel injection period according to, the injection pressure timing setting means for performing the detection timing of the fuel injection pressure in synchronization with the crank angle of the engine, and the transient state of the engine A transient state detecting means for detecting, and an injection pressure change amount calculating means for calculating an instantaneous injection pressure change amount according to the crank angle of the fuel injection pressure,
When it is determined that the engine is in a transient state, an injection pressure correction means for correcting the injection pressure value used for the calculation of the fuel injection period by the amount of change in the instantaneous injection pressure is provided.

The injection pressure change amount calculation means may calculate the instantaneous injection pressure change amount from the injection pressure of the cylinder in which the previous injection has ended and the injection pressure of the cylinder in which the two-previous injection has ended. The instantaneous injection pressure change amount may be calculated from a two-dimensional map including the high-pressure pump valve energization timing and the command fuel injection amount.

[0012]

According to the present invention, the fuel injection pressure detection timing is synchronized with the engine crank angle, and when a transient state of the engine is detected, the instantaneous injection pressure corresponding to the fuel injection pressure crank angle is detected. The change amount is calculated, and the injection pressure value used for calculating the fuel injection period is corrected by the change amount of the instantaneous injection pressure.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a pressure accumulation type fuel injection control device for an internal combustion engine according to the present invention will be described below with reference to the drawings. First, referring to FIG. 1, a pressure accumulation type fuel injection control device for an internal combustion engine which is the premise of the present invention. The schematic configuration of will be described. Internal combustion engine (engine) 1
Is provided with an injector 2 for injecting high-pressure fuel into the combustion chamber of each cylinder, and fuel injection from the injector 2 to the engine 1 is controlled by opening / closing the injection control solenoid valve 3. . The injector 2 is connected to a high pressure accumulating pipe common to all the cylinders, a so-called common rail 4, and while the injection control solenoid valve 3 is open, the fuel in the common rail 4 is injected from the injector 2 into the combustion chamber of the engine 1. . Therefore, it is necessary for the common rail 4 to continuously accumulate a high predetermined pressure corresponding to the fuel injection pressure. For this reason, the common rail 4 has a supply pipe 6 and a check valve 5.
A high-pressure pump 7 capable of supplying high-pressure fuel is connected via. The high-pressure pump 7 reciprocates the fuel sucked from the fuel tank 8 through the well-known low-pressure supply pump 9 by a cam (not shown) synchronized with the rotation of the engine 1 so as to increase the pressure to a predetermined high pressure required and then the common rail 4 The discharge amount control device 10 is provided.
The discharge amount control device 10 includes a high pressure pump valve that opens and closes an intake port of the high pressure pump 7, and controls the discharge amount by adjusting the effective pressure feeding stroke of the high pressure pump 7 by the high pressure pump valve.

Injection control solenoid valve 3 and discharge amount control device 10
The high-pressure pump valve of the electronic control unit (hereinafter simply referred to as EC
Its operation is controlled by a control signal output from U) 11. Detection signals from the engine speed sensor 12 and the accelerator opening sensor 13 are input to the ECU 11, a pressure sensor 14 that detects the actual common rail pressure, and various sensors 15 such as water temperature, intake temperature, and intake pressure.
The input signal from is input. The ECU 11 determines the operating state of the engine based on these input signals, performs arithmetic processing according to a predetermined program, and outputs an optimum control signal to the injection control solenoid valve 3 and the discharge amount control device 10. Although not shown, the ECU 11 has a memory (RAM, RAM, etc.) for storing detection data, control programs, and the like.
ROM) is provided.

FIG. 2 shows a control block diagram in the ECU 11 of FIG. 1, and the same structural blocks as those of the conventional one shown in FIG. 9 are designated by the same reference numerals. Also in the control block shown in FIG. 2, normally, the target injection amount is calculated by the target injection amount calculation circuit 91 based on the actual engine speed and the accelerator opening degree, and based on the calculated target injection amount and the actual engine speed. The target common rail pressure calculation circuit 92 calculates the target common rail pressure. Then, the high pressure pump valve energization timing calculation circuit 94 calculates the energization time based on the comparison result in the comparison circuit 93 between the target common rail pressure and the actual common rail pressure described later, and the high pressure pump valve drive circuit 95 drives the high pressure pump valve. It The pressure of the common rail is detected by the actual common rail pressure detection circuit 96, and this actual common rail pressure is input to the comparison circuit 93 and the injector energization time calculation circuit 97. In this way, the high-pressure pump valve responds to the deviation between the actual common rail pressure and the target common rail pressure by
PID control is performed by the comparison circuit 93, the high pressure pump valve energization timing calculation circuit 94, and the high pressure pump valve drive circuit 95.

On the other hand, in the fuel injection amount control, the optimum energization time to the injector is calculated by the injector energization time calculation circuit 97 based on the target fuel injection amount and the actual common rail pressure, and a command pulse is output to the injector drive circuit 98. Then, the injector is driven and fuel injection is performed. The above is the same part as the conventional control block. In the present invention, in addition to these configurations, the transient state determination circuit 2
1 is provided. Further, an instantaneous common rail pressure change amount calculation circuit 22 to which the output from the actual common rail pressure detection circuit 96 is input is provided, and the output of this instantaneous common rail pressure change amount calculation circuit 22 is input to the common rail pressure correction circuit 23. It has become so. The output from the actual common rail pressure detection circuit 96 is input to the injector energization time calculation circuit 97 via the changeover switch 24, and the common rail pressure correction circuit is input to the other input of the changeover switch 24. The outputs of 23 are connected.

That is, in the present invention, the common rail pressure applied to the injector energization time calculation circuit 97 is the pressure value from the actual common rail pressure detection circuit 96 or the common rail pressure correction circuit depending on whether the engine is in a transient state. One of the pressure values from 23. In this embodiment, the transient state determination circuit 21 determines whether the engine is in a transient state or a steady state according to the accelerator opening. If the engine is in a steady state, the actual common rail pressure obtained from the actual common rail pressure detection circuit 96 is directly applied to the injector energization time calculation circuit 97. On the other hand, if it is determined that the engine is in a transient state, it is instantaneous. Common rail pressure change amount is instantaneous common rail pressure change amount calculation circuit 2
The correction is performed by the common rail pressure correction circuit 23 and is added to the injector energization time calculation circuit 97.

FIG. 3 is a timing chart of the calculation of the instantaneous common rail pressure change amount in the control block constructed as shown in FIG. In the present invention, in order to improve the injection amount control accuracy at the time of transition, the instantaneous actual common rail pressure NPC is sampled in synchronization with the rotation speed pulse Ne from the crank angle sensor. Moreover, the timing of sampling is synchronized with a predetermined number, for example, the No. 2 pulse of the rotation speed pulse Ne immediately before the injection (injection of the injector drive pulse) in the cylinder.

Then, for example, when the next injection is performed in the cylinder (i), the instantaneous actual common rail pressure NPC (i-1) A / D converted in the cylinder (i-1) and the current cylinder ( Instantaneous actual common rail pressure NP A / D converted in i)
Difference ΔNPC of C (i), that is, ΔNPC = NPC
(I) -NPC (i-1) is added to NPC (i), and NP
C (i) + NPC (i) -NPC (i-1) = 2NPC
(I) -NPC (i-1) is reflected in the injector drive pulse width (energization time TQ). However, the cylinders (i-1), (i), and (i + 1) are not the actual cylinder numbers, but the cylinder in which fuel injection was performed previously, the cylinder in which fuel injection is performed this time, and the next fuel injection are performed. Shows a cylinder.

With the above-mentioned structure, a value very close to the actual common rail pressure required for the next injection is expected, and the accuracy of the energization time TQ is improved.
The accuracy of the fuel injection amount can be improved. Next, the procedure of the injection amount estimation control of the first embodiment of the present invention in the pressure accumulation type fuel injection control device for an internal combustion engine configured as described above will be described with reference to FIG.
This will be described with reference to the flowchart shown in. In the following description, the instantaneous actual common rail pressure NPC (i) after A / D conversion in cylinder (i) will be simply referred to as PC (i).

First, in step 401, i + 1
In order to determine the fuel injection amount of the cylinder, the command fuel injection amount QFIN at that time is fetched. Then, step 4
In 02, the actual common rail pressure PC of the i cylinder is taken in. At this time, the sampling of the actual common rail pressure PC is performed in synchronization with the crank angle for each predetermined rotation speed pulse Ne emitted from the crank angle sensor, and the sampling is performed once for each cylinder. Therefore, the pressure PC is the latest actual common rail pressure value obtained by the crank angle synchronization interruption one cylinder before.

At step 403, it is determined whether the engine is in a transient state. Since this transient state can be performed by a known method such as detection of engine load, it will not be described here. Then, when the engine is in the transient state (YES), the routine proceeds to step 404, where the difference ΔPC between the previous sampling value PC (i) and the sampling value PC (i−1) of the previous two times is calculated. Step 4
Reference numeral 05 denotes the injection pressure of the next cylinder, which is the change amount ΔPC of the injection pressure.
It is calculated based on the estimated value, and Δ calculated in step 404 is used for the previous sampling value PC (i).
The fuel injection period TQ is determined by map interpolation from the value obtained by adding PC and the command injection amount QFIN fetched in step 401. Then, in step 406, the previous sampling value PC (i) is stored in the memory as the sampling value PC (i−1) of the previous two times for the next calculation.

On the other hand, when it is determined in step 403 that the engine is not in the transient state (NO), the process proceeds to step 407, where the map is made from the previous sampling value PC (i) and the command injection amount QFIN fetched in step 401. The fuel injection period TQ is determined by interpolation. Conventionally, this step 407 is executed regardless of whether the engine is in a transient state, and the fuel injection period TQ is determined by map interpolation.

Next, the features of the common rail type injection system in the first embodiment will be described. The fuel injection amount control in this system is performed in accordance with the command injection amount QFIN of the previous fuel injection cylinder i and the actual common rail pressure PC (i), the valve opening time of the injection valve of the next fuel injection cylinder i + 1, the fuel injection period. It calculates TQ. If the sampling of the actual common rail pressure PC (i) is not performed immediately before the calculation of the fuel injection period, the difference between the common rail pressure input to the electronic control unit ECU and the actual common rail pressure due to the change in the engine speed causes an error in the engine. It increases with an increase in the number of revolutions and deteriorates the control accuracy of the fuel injection amount.

For this reason, in the first embodiment, the sampling of the actual common rail pressure PC (i) is performed in a crank angle cycle for each predetermined rotation speed pulse Ne emitted from the crank angle sensor, and 1 for each cylinder. The actual common rail pressure error due to engine speed is reduced by sampling once. In addition, the difference ΔPC between the previous sampling value PC (i) of the common rail pressure and the sampling value PC (i-1) of the previous two times is added to the previous sampling value PC (i) to estimate the next fuel injection pressure and the fuel injection period is determined. To be done. In this way, the fuel injection amount closer to the command injection amount can be supplied by predictively calculating the fuel injection pressure of the next time from the difference between the sampling values of the previous time and the sampling value of the previous time.

FIGS. 5 (a) and 5 (b) show a conventional method for calculating the fuel injection period TQ when the engine is in a transient state, and the fuel injection period TQ according to the first embodiment shown in FIG. It is shown by comparing with the calculation method of. In the figure, the solid line indicates the command fuel injection amount QFIN, the broken line indicates the command injection pressure PFIN, and the alternate long and short dash line indicates the actual injection pressure PC.
In both the conventional example of (1) and the present invention of (b), the command injection pressure P when the command fuel injection amount QFIN increases stepwise after the engine enters the transient state after the fuel injection of the 0th cylinder
The calculation method of the fuel injection period TQ based on FIN and the actual injection pressure PC is shown. As can be seen from this figure, the calculation of the fuel injection period TQ according to the first embodiment of the present invention requires more data to calculate the fuel injection period TQ, so the fuel injection period TQ should be calculated more accurately. You can

In the embodiment described above, the estimated value of the injection pressure of the next cylinder is calculated by the difference between the common rail pressure samplings of the previous and the previous two times. This estimated value is the high pressure pump valve solenoid valve energization timing ATF. The same result can be obtained even if it is obtained from the two-dimensional map of the command fuel injection amount QFIN. Therefore, this method will be described as a second embodiment with reference to FIG.

FIG. 6 shows a flowchart for calculating the fuel injection time (injector energization time) TQ in the second embodiment of the present invention. First, in step 601, the command fuel injection amount QFIN at that time is taken in order to determine the fuel injection amount of the i-cylinder. Then, in step 602, the actual common rail pressure PC of the i-cylinder
Is captured. At this time, the sampling of the actual common rail pressure PC is performed in synchronization with the crank angle for each predetermined rotation speed pulse Ne emitted from the crank angle sensor, and the sampling is performed once for each cylinder. Therefore, the pressure PC is 1
It is the latest actual common rail pressure value obtained by the crank angle synchronization interrupt before the cylinder.

At step 603, it is determined whether the engine is in a transient state. This transient state is, for example,
This can be performed depending on whether the difference between the command injection pressure PFIN and the common rail pressure PC (i) of the previous sampling is 10 MPa or more. Then, when the engine is in the transient state (YES), the routine proceeds to step 604, where the energization timing ATF of the high pressure pump solenoid valve is fetched.
After that, in step 605, the two parameters of the energization timing ATF of the high-pressure pump solenoid valve and the command injection amount QFIN fetched in step 601 are calculated from FIG.
The transient injection pressure correction amount ΔPC is calculated using this map. Thereafter, in step 606, the fuel injection period TQ is calculated from the value obtained by adding the injection pressure correction amount ΔPC to the injection pressure PC (i) of the previous cylinder i and the command injection amount QFIN.

On the other hand, when it is determined in step 603 that the engine is not in the transient state (NO), the process proceeds to step 607, where the map is made from the previous sampling value PC (i) and the command injection amount QFIN fetched in step 601. The fuel injection period TQ is determined by interpolation. In the second embodiment, the engine transient determination conditions are set to the command injection pressure PFIN and the previous sampling common rail pressure PC.
Whether or not the difference in (i) is 10 MPa or more is determined, but the accelerator opening change amount, the Ne change amount, the target injection amount change amount,
The change amount of the target injection pressure may be adopted. When the accelerator opening change amount is used as the engine transient determination condition, the accelerator opening is A / D converted at regular time intervals.
It may be determined by comparing the A / D converted value of the previous accelerator opening and the A / D converted value of this time, and determining whether the difference is larger than the transient determination accelerator opening amount stored in advance.

FIG. 8 schematically shows the method of calculating the fuel injection period TQ in the embodiment of FIG. 6 when the engine is in a transient state. In the figure, the solid line shows the command fuel injection amount QFIN, the broken line shows the command injection pressure PFIN, and the alternate long and short dash line shows the actual injection pressure PC. The engine enters a transient state after the fuel injection of the first cylinder, and the command fuel injection amount QFIN
Shows a method of calculating the fuel injection period TQ based on the command injection pressure PFIN and the actual injection pressure PC when the value increases stepwise. As can be seen from this figure, in the fuel injection period TQ of the second embodiment, when the difference between the command injection pressure PFIN and the actual injection pressure PC is 10 MPa or more apart, it is set as a transient state and the control of steps 604 to 606 is performed. And the difference between the command injection pressure PFIN and the actual injection pressure PC is 10M.
When it becomes less than Pa, it is calculated by the normal control of step 607. As described above, also in the second embodiment, since the amount of data for calculating the fuel injection period TQ in the transient state is large, the fuel injection period TQ can be calculated more accurately.

[0032]

As described above, according to the pressure-accumulation type fuel injection control device for an internal combustion engine of the present invention, it is possible to avoid complication of a program and to improve exhaust gas performance as simply as possible. effective.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a pressure accumulation type fuel injection control device for an internal combustion engine of the present invention.

FIG. 2 is a control block diagram in the ECU of FIG.

FIG. 3 is a timing chart diagram for calculating an instantaneous common rail pressure change amount in the control block configured as in FIG.

FIG. 4 is a flowchart showing a procedure of injection amount estimation control according to the first embodiment of the present invention.

FIG. 5 is a view showing a comparison between the conventional fuel injection period calculation method and the present invention calculation method when the engine is in a transient state, and FIG. 5A is a diagram showing a conventional fuel injection period calculation method. , (B) are diagrams showing a method of calculating a fuel injection period according to the embodiment of FIG. 4.

FIG. 6 is a flowchart showing a procedure of injection amount estimation control according to a second embodiment of the present invention.

FIG. 7 is a map for calculating a transient injection pressure correction amount from two parameters of an energization timing command injection amount of a high pressure pump solenoid valve.

FIG. 8 is a diagram illustrating a calculation method of a second embodiment of the present invention for a fuel injection period when the engine is in a transient state.

[FIG. 9] E of a conventional pressure-accumulation fuel injection control device for an internal combustion engine
It is a figure which shows the control block of CU.

FIG. 10 is a diagram showing a conventional method for calculating a fuel injection period during a transition of an engine.

FIG. 11A shows a relationship between a fuel injection period, a target injection amount, and an actual common rail pressure during a conventional engine transient, and FIG. 11B shows a calculation error of a fuel injection period during a transient. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine (engine) 2 ... Injector 3 ... Injection control solenoid valve 4 ... Common rail (high pressure accumulator pipe) 5 ... Check valve 6 ... Supply pipe 7 ... High pressure pump 8 ... Fuel tank 9 ... Low pressure supply pump 10 ... Discharge amount Control device 11 ... Electronic control unit (ECU) 12 ... Rotation speed sensor 13 ... Accelerator opening sensor 14 ... Pressure sensor 21 ... Transient state determination circuit 22 ... Instantaneous common rail pressure change amount calculation circuit 23 ... Common rail pressure correction circuit 24 ... Changeover switch 91 ... Target injection amount calculation circuit 92 ... Target common rail pressure calculation circuit 93 ... Comparison circuit 94 ... High pressure pump valve energization timing calculation circuit 95 ... High pressure pump valve drive circuit 96 ... Actual common rail pressure detection circuit 97 ... Injector energization time calculation circuit 98 ... Injector drive circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiro Itazu 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Co., Ltd.

Claims (3)

[Claims] 1. A command fuel injection amount and fuel injection timing according to a predetermined program based on detected values of engine operating state parameters such as engine speed and accelerator opening and detected values of injection pressure of cylinders for which previous injection has ended. , And a fuel injection control device for an internal combustion engine that calculates a command value of the injection pressure of a cylinder in which fuel injection is next performed and injects fuel in a fuel injection period according to the injection pressure command value of the next cylinder. Injection pressure timing setting means for synchronizing the detection timing of the injection pressure with the crank angle of the engine, transient state detection means for detecting the transient state of the engine, and instantaneous injection pressure change according to the crank angle of the fuel injection pressure The injection pressure change amount calculating means for calculating the fuel injection amount, and the injection pressure value used for the calculation of the fuel injection period when the engine is judged to be in a transient state. Accumulator fuel injection control apparatus for an internal combustion engine, characterized by comprising an injection pressure correction means for correcting the amount of change. 2. The injection pressure change amount calculation means calculates the instantaneous injection pressure change amount from the injection pressure of a cylinder that has completed previous injection and the injection pressure of a cylinder that has completed two-previous injection. The pressure accumulation type fuel injection control device for an internal combustion engine according to claim 1. 3. The injection pressure change amount calculation means calculates the instantaneous injection pressure change amount from a two-dimensional map composed of a high-pressure pump valve energization timing and a command fuel injection amount. A pressure-accumulation fuel injection control device for an internal combustion engine as described.