JP2001140689A - Accumulator fuel injector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an accumulator fuel injector capable of injecting fuel quantity with a minimum error. SOLUTION: This injector calculates command injection quantity based on the current operation state (Steps 100 and 110) and also calculates the injection time of the injector based on detected fuel pressure (Step 120). It also calculates virtual injection time (Step 180). At the time for injection, the fuel pressure in an accumulator pipe in injection is detected (Step 240). When the pressure is normally detected (Step 250), the injection period is recalculated from the command injection quantity based on the fuel pressure in injection (Step 260).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure accumulating fuel injection device for supplying fuel to an injector from a pressure accumulating pipe in which high pressure fuel is accumulated.

[0002]

2. Description of the Related Art Conventionally, in a diesel internal combustion engine,
The command injection timing and the command injection amount of the fuel are calculated according to the load such as the rotation speed and the accelerator opening. Further, in an internal combustion engine using an accumulator type fuel injection device that supplies fuel from the accumulator pipe to the injector, the fuel pressure of the accumulator pipe is detected, and based on the detected fuel pressure, the injection timing and the injection timing are determined from the command injection timing and the command injection amount. The injection period is calculated, and the power supply to the injector is controlled based on the pulse output from the rotation speed sensor.

For example, in the device disclosed in Japanese Patent Application Laid-Open No. 3-18645, as shown in FIG. 13, when a predetermined pulse is output from a rotation speed sensor, the fuel pressure NP
C, and based on the detected fuel pressure NPC, the injection timing pulse number CNECAMF and the remaining time TTM
The injection timing and the injection period TQMF are calculated.

That is, as shown in FIG. 13, when calculating the injection timing, the command injection timing TFIN from the top dead center TDC is calculated.
Delay time TD calculated based on the fuel pressure NPC
M is used to calculate the injection timing. The command injection timing TFIN is calculated by an angle (° C.). The same applies to the following description. For example, a predetermined pulse from the rotation speed sensor is used as a control reference position, an injection timing including the injection timing pulse number CNECAMF and the remaining time TTMF is calculated from the control reference position, and the pulses from the control reference position are counted. The injection time is controlled by measuring the remaining time TTMF.

Therefore, since the injection timing must be calculated before the control reference position is reached at the latest, the detection of the fuel pressure NPC in the pressure accumulating pipe must be performed before that. Similarly, the calculation of the injection period TQMF is also performed based on the fuel pressure NPC until reaching the control reference position.

When performing pilot injection, the number C of pilot injection timing pulses from the control reference position is determined based on the command injection timing TFIN, interval TINT, injection end delay time TDEP, and pilot injection period TQPF.
The pilot injection timing including the NECCAPF and the remaining time TTPF is calculated. Therefore, it is necessary to calculate the pilot injection period TQPF calculated based on the fuel pressure NPC before the control reference position is reached.
Even if C is slow, it must be detected before it reaches the control reference position.

However, the fuel pressure in the pressure accumulating pipe fluctuates due to fuel pressure feeding from a high-pressure fuel supply pump and the like. In particular, during transients such as acceleration, the pressure between the detected fuel pressure and the fuel pressure during injection is increased. Due to the difference, an error occurs between the calculated command injection amount and the actual injection amount by the injector.

In order to reduce this error as much as possible, as disclosed in Japanese Patent Application Laid-Open No. H5-125985, the fuel pressure in the accumulator pipe is detected at the end of energization of the injector, and the fuel pressure in the next cylinder is determined based on the fuel pressure. For calculating the injection timing and the injection period of the engine.

[0009]

However, even if the fuel pressure is detected at the end of energization of the injector and the injection timing and injection period of the next cylinder are calculated, the calculation for one injection is delayed, so that during the transition, the fuel pressure is detected. There is a problem that the pressure difference between the detected fuel pressure in the cylinder and the actual fuel pressure in the next cylinder is large, causing a large difference between the calculated command injection amount and the actual injection amount.

[0010] An object of the present invention is to provide a pressure accumulating type fuel injection device having a small injection amount error.

[0011]

In order to achieve the above object, the present invention takes the following means to solve the problem. That is, an injector that is provided for each cylinder of the internal combustion engine and injects fuel into the cylinder, a pressure accumulating pipe that holds the fuel accumulated at a high pressure and supplies the fuel to the injector, and a fuel pressure detection that detects the fuel pressure of the pressure accumulating pipe Means, and a pressure accumulating fuel injection device comprising: a control means for performing fuel injection control by the injector based on the fuel pressure.
The fuel injection timing of the injector is calculated based on the detected fuel pressure, and the fuel pressure at the time of injection of the accumulator pipe is detected at the time of the fuel injection timing, based on the fuel pressure at the time of injection. This is a pressure-accumulation type fuel injection device characterized by calculating an injection period.

Further, the control means calculates an injection timing of the injector based on the detected fuel pressure, calculates a tentative injection period, and when the injection timing is reached, the injection timing of the pressure accumulation pipe is calculated. The fuel pressure may be detected, and when the fuel pressure during injection is normally detected, the injection period at that time may be recalculated based on the fuel pressure during injection. Further, the control means also detects the fuel pressure during injection of the accumulator pipe at the time of each injection during each injection of the multi-injection, and determines the injection period at that time based on the fuel pressure during injection. You may make it calculate.

Alternatively, the control means calculates a command injection amount based on an operation state, calculates an injection timing of the injector based on the detected fuel pressure, and sets the injection timing when the injection timing is reached. The fuel pressure at the time of injection of the pressure accumulation pipe may be detected, and the injection period at that time may be calculated from the command injection amount based on the fuel pressure at the time of injection. Further, the control means may include a switching means for switching the calculation of the injection timing of the main injection based on the fuel injection interval during the multiple injection.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a schematic configuration of a pressure accumulating fuel injection device for a diesel internal combustion engine. In the diesel internal combustion engine 1, an injector 2 is provided for a combustion chamber of each cylinder, and fuel injection from the injector 2 to the internal combustion engine 1 is controlled by turning on / off an injection control solenoid valve 3. . The injector 2 is connected to a common high-pressure accumulator pipe 4 for each cylinder, and the fuel in the accumulator pipe 4 is injected into the internal combustion engine 1 by the injector 2 while the injection control solenoid valve 3 is open.

That is, the injector 2 is provided with a back pressure chamber on the back pressure side of the needle for opening and closing the injection hole, in which the fuel pressure of the pressure accumulating pipe 4 acts, and further, between the back pressure chamber and the low pressure side. An injection control solenoid valve 3 is provided. When the injection control solenoid valve 3 is closed, the needle closes the injection hole by the action of fuel pressure from the pressure accumulating pipe 4 in the back pressure chamber, and when the injection control solenoid valve 3 is opened, the needle closes. When the fuel is drawn to the low pressure side, the needle is lifted, and the injection is performed by opening the injection hole. For this reason, it is necessary that the high pressure fuel corresponding to the fuel injection pressure be continuously stored in the pressure accumulation pipe 4, and the high pressure supply pump 7 is connected to the supply pipe 6 having the check valve 5 interposed.

The high-pressure supply pump 7 reciprocates a plunger with a cam (not shown) synchronized with the rotation of the internal combustion engine 1 to move the fuel sucked from the fuel tank 8 through the fuel supply pump 9 to a required predetermined pressure. The pressure is increased to a high pressure and supplied to the pressure accumulating pipe 4. The discharge amount control device 10 for maintaining the fuel pressure at a predetermined high pressure is provided.

Injection control solenoid valve 3 and discharge control device 10
Is controlled by a control signal output from the electronic control circuit 11. The electronic control circuit 11 receives detection signals from the rotation speed sensor 12 and the accelerator opening sensor 13, and also detects a fuel pressure in the accumulator pipe 4, a pressure sensor 14, and water temperature, intake air temperature, intake pressure and the like. Various sensors 15
Is input.

The electronic control circuit 11 determines the operating state of the internal combustion engine 1 based on these input signals, and outputs control signals to the injection control solenoid valve 3 and the discharge amount control device 10. Further, the electronic control circuit 11 includes a memory (neither a RAM nor a ROM is shown) for storing detection data, a control program, and the like.

Next, an example of the fuel injection control process performed in the electronic control circuit 11 will be described with reference to the flowcharts of FIGS. First, the rotation speed Ne is captured based on the detection signal of the rotation speed sensor 12, and the accelerator opening Accp is determined based on the detection signal of the accelerator opening sensor 13.
(Step 100). Next, this rotation speed Ne
Command injection quantity Q using a characteristic map (not shown) according to a predetermined program based on the accelerator opening Accp
FIN is calculated (step 110).

Subsequently, similarly, a characteristic map (not shown)
Then, the command injection timing TFIN is calculated from the rotational speed Ne and the command injection amount QFIN (step 120). And
The fuel pressure NPCn of the pressure accumulation pipe 4 is taken in based on the detection signal of the pressure sensor 14 (step 130). The subscript n
Indicates the amount detected by executing the current process.

Next, it is determined whether or not to execute a multi-injection in which the fuel is injected in a plurality of times such as a pilot injection (step 140). Whether to execute multiple injections
It may be determined by operating conditions or the like, or may be set in advance by a setting switch or the like.

If it is determined that the fuel injection is not the multi-injection, an expected pressure NPCF is calculated from the fuel pressure NPCn taken in step 130 based on the following equation (step 150). Here, NPCn-1 is calculated in the previous step 130.
NPCMn-1 is the fuel pressure at the time of injection taken in the process of the step 240 described later.

NPCF = NPCn + ΔPC ΔPC = NPCMn−1−NPCn−1 The pressure difference ΔPC between the fuel pressure NPCn−1 in the previous processing and the fuel pressure NPCMn−1 in the previous injection is determined by the current processing. Even at the time of steady running or transition, almost the same occurs, so the estimated pressure NPCF taking into account the pressure difference ΔPC is calculated to reduce the error at the time of the current injection.

Next, an injection delay time TDM is calculated from the characteristic map (FIG. 6) based on the calculated expected pressure NPCF (step 160). The injection delay time TDM is shown in FIG.
As shown in (2), this is the time from the start of energization of the injector 2 to the actual injection of fuel. The injector 2 has a configuration in which the needle lifts and opens the valve under the action of the supplied fuel pressure, so that the injection delay time varies depending on the fuel pressure. The relationship between the fuel pressure and the injection delay time may be obtained in advance through experiments or the like to create a characteristic map.

Subsequently, the injection timing is calculated based on the command injection timing TFIN calculated by the processing of step 120 and the injection delay time TDM calculated by the processing of step 160 (step 170). In this embodiment, as shown in FIG. 5, the injection timing includes an injection timing pulse number CNECAMF from the control reference position to immediately before the injection start, and a remaining time TTMF from this pulse to the start of the injection.

(A-TFIN) / X = CNECAMF + Z (Z / X) × Y-TDM = TTMF If TTMF <0, the following processing is performed. CNECAMF ← CNEMF−1 TTMF ← TTMF + Y Here, CNECAMF is an integer, and Z is a remainder. As shown in FIG. 5, A is the top dead center T from the control reference position.
X is an angle corresponding to one pulse output from the rotation speed sensor 12. Y is the time required to rotate by the angle X at the rotation speed at that time.

Next, the command injection amount QFIN and the estimated pressure NPC
F and the temporary injection period T based on the characteristic map (FIG. 7).
The QMF is calculated (Step 180). Then, it is determined whether or not it is the control reference position based on the output signal from the rotation speed sensor 12 (step 190). If it is not the control reference position, it waits until it reaches the control reference position, and if it does, it starts counting pulses output from the rotation speed sensor 12 (step 200).

Then, it is determined whether or not the counted pulse number has reached the injection timing pulse number CNECAMF (step 210). Injection timing pulse number CNECAMF
If not, the injection timing pulse number CNECA
Wait until MF is reached. Injection timing pulse number CNECA
When MF is reached, it is determined whether or not the injection time excess time TTMF has elapsed (step 220).

It waits until the injection time excess time TTMF has elapsed, and when the injection time excess time TTMF has elapsed, energization of the injector 2 is started (step 23).
0). Thus, the needle (not shown) of the injector 2 receives the fuel pressure and starts lifting in the valve opening direction.

At this time, the fuel pressure NPCMn at the time of injection of the pressure accumulation pipe 4 detected by the pressure sensor 14 is taken in (step 240). Next, it is determined whether or not the absolute value of the difference between the taken-in fuel pressure NPCMn at the time of injection and the fuel pressure NPPCn taken in the process of step 130 is equal to or more than a predetermined value α (step 250).

If the absolute value of the difference is smaller than the predetermined value α, it is determined that the taken-in injection fuel pressure NPCMn has been taken normally without being affected by noise or the like, and the commanded injection amount QFIN and the injected fuel pressure NPCMn are determined. Based on NPCMn,
The injection period TQMF is recalculated from the characteristic map (FIG. 7) (step 260). Note that the predetermined value α may be determined by experiments or the like.

On the other hand, when the absolute value of the difference is larger than the predetermined value α, it is determined that the taken fuel pressure NPCMn is an abnormal value affected by noise or the like, and the provisional injection period calculated by the processing in step 180 is determined. TQMF is applied as it is as the injection period (step 270).

Next, it is determined whether or not the injection period TQMF has elapsed (step 280), and it waits until the injection period TQMF has elapsed. When the injection period TQMF has elapsed, the energization of the injector 2 is terminated. (Step 29
0). As a result, the needle of the injector 2 receives the fuel pressure and lifts in the valve closing direction, ending the fuel injection. After executing the process of step 290, the control process is temporarily terminated.

As described above, the injection timing is calculated from the estimated pressure NPCF, and the injection fuel pressure NPCMn is taken in.
Since the injection period TQMF is calculated, the injection period TQMF can be calculated based on the actual fuel pressure NPCMn at the time of injection. For example, as shown in FIG. 5, the temporary injection period TQMF is calculated as shown by a broken line, but the fuel pressure during injection NPCM is calculated.
When n is taken in and the injection period TQMF is calculated, it is corrected as shown by the solid line. Therefore, regardless of the transition,
Command injection amount QFIN calculated by the process of step 110
And the error between the command injection amount QFIN and the actual injection amount can be reduced.

On the other hand, if it is determined that the fuel injection is multi-injection by executing the processing in step 140, the pilot injection amount QPILOT is calculated using a characteristic map (not shown) (step 300). Then, the pilot injection amount Q is calculated from the command injection amount QFIN calculated by the process of step 110.
The main injection amount QMIN is calculated by subtracting PILOT (step 310).

QMIN ← QFIN−QPILOT Next, the interval T between the pilot injection and the main injection
INT (see FIG. 10) is calculated from the characteristic map (FIG. 8) based on the rotation speed Ne and the command injection amount QFIN (step 320). Subsequently, the estimated pressure NPCF during the main injection
M is calculated by the following equation (step 330).

NPCFM ← NPCn + (NPCMn−1−NPCn−1) Here, NPCn is the fuel pressure of the pressure accumulation pipe 4 taken in at step 130, and NPCMn−1 is taken at the previous processing at step 240. NPCn-1 is the fuel pressure of the pressure accumulating pipe 4 taken in the previous step 130.

Next, the expected pressure NPC during the pilot injection
FP is calculated by the following equation (step 340). NPCFP ← NPCn + (NPCPn−1−NPCn−1) Here, NPCPn−1 is the fuel pressure of the pressure accumulation pipe 4 taken in the previous process of step 530 described later.

Subsequently, the expected pressure NPCFP during the pilot injection calculated by the process of step 340 and the pilot injection amount QPILOT calculated by the process of step 300
From this, the provisional pilot injection period TQPF is calculated based on a characteristic map (not shown) similar to FIG. 7 (step 3).
50).

Next, the estimated pressure NPC at the time of pilot injection
A pilot injection end delay time TDEP is calculated from FP and pilot injection amount QPILOT based on a characteristic map (not shown) (step 360). The pilot injection end delay time TDEP is a time from when the injection control solenoid valve 3 is turned off to when the fuel injection from the injector 2 actually ends. Then, the estimated pressure NP during the main injection
The main injection delay time TDM is calculated from the CFM based on the characteristic map shown in FIG. 6 (step 370).

Next, based on the top dead center TDC, the command injection timing TFIN, the interval TINT, the pilot injection end delay time TDEP, and the provisional pilot injection period TQPF calculated by the processing in step 350, as shown in FIG. The pilot injection timing pulse number CNECAPF
And pilot injection time surplus time TTPF to step 17
The calculation is performed in the same manner as the process of 0 (step 380).

Thereafter, it is determined whether or not a hunting prevention flag F set by a process described later is 1 (step 390). If it is 1, it is determined whether or not the interval TINT exceeds the first threshold value T1 (step 400). If it is greater than the first threshold value T1, the main injection timing pulse number CNECAMF and the main injection timing are determined based on the command injection timing TFIN and the main injection delay time TDM based on the top dead center TDC in the same manner as in the process of step 170. The remaining time TTMF is calculated (step 4).
10). Then, 1 indicating that the surplus angle control is being executed is substituted into the hunting prevention flag F (step 42).
0).

On the other hand, if it is determined that the interval TINT is smaller than the first threshold value T1 by executing the processing in step 400, the main injection timing pulse number CNECAM is set.
The pilot injection timing pulse number CNECAPF is substituted for F (step 430). Next, as shown in FIG.
Based on the command injection timing TFIN and the main injection delay time TDM calculated by the processing of step 370, the main injection timing remaining time T
The TMF is calculated (Step 440). Then, 0 indicating that time control is being executed is substituted for the hunting prevention flag F (step 450).

When it is determined that the hunting prevention flag F is not 1 by executing the processing of step 390, it is determined whether or not the interval TINT is larger than the second threshold value T2 (step 460). Second threshold T
When it is larger than 2, the remainder angle control of step 410 and below is executed, and when it is smaller than the second threshold value T2, the time control of step 430 and below is executed. As shown in FIG. 9, by using the first threshold value T1 and the second threshold value T2, frequent switching between the surplus angle control and the time control can be prevented. Steps 390, 400, 420, 45
Execution of the process of 0,460 functions as the switching means.

After the processing of step 420 or step 450 is executed, the temporary main injection period TQMF is set as shown in FIG. 7 by the main injection amount QMAIN calculated by executing the processing of step 310 and step 330 and the estimated pressure NPCFM during main injection. It is calculated based on a similar characteristic map (not shown) (step 470). Next, the rotation speed sensor 1
It is determined whether or not the pulse detected by step 2 has reached the control reference position (step 480). If the pulse has not reached the control reference position, the process waits until the pulse reaches the control reference position.

At the control reference position, counting of the number of pulses from the control reference position is started (step 4).
90). Then, it is determined whether or not the counted pulse number has reached the pilot injection timing pulse number CNECAPF (step 500). If it has not reached the pilot injection timing pulse number CNECAPF, the process waits until the pilot injection timing pulse number CNECAPF is reached. If not, it is determined whether the pilot injection time excess time TTPF has elapsed (step 510).

If the pilot injection time excess time TTPF has not elapsed, the process waits until the time elapses, and if it has elapsed, energization of the injector 2 is started (step 5).
20). Next, the fuel pressure NPCPn at the time of pilot injection of the pressure accumulation pipe 4 at that time is detected by the pressure sensor 14 and taken in (step 530). It is determined whether or not the absolute value of the difference between the newly detected pilot injection fuel pressure NPCPn and the fuel pressure NPPCn acquired in the processing of step 130 is larger than a predetermined value β (step 540).

If it is smaller than the predetermined value β, it is determined that the pilot injection fuel pressure NPCPn has been taken in normally, and the pilot injection period TQPF is re-established by this pilot injection fuel pressure NPCPn in the same manner as in the processing of step 350. It is calculated (step 550). And
It is determined whether or not the recalculated pilot injection period TQPF has elapsed (step 560), and after the lapse, the power supply to the injector 2 is terminated (step 570).

On the other hand, if it is determined in step 540 that the value is larger than the predetermined value β, it is determined that the intake of the fuel pressure NPCPn during the pilot injection is abnormal due to the influence of noise or the like. The calculated temporary pilot injection period TQPF is applied (step 580). The provisional pilot injection period T
It is determined whether the QPF has elapsed (step 560),
After the passage of time, the power supply to the injector 2 is terminated (step 570).

Next, the processing of step 210 and subsequent steps is executed, and as described above, as shown in FIGS.
The main injection period TQMF is recalculated by taking in the main injection fuel pressure NPCMn, and the main injection is executed. For example, as shown in FIG. 10 and FIG. 11, the provisional pilot injection period TQPF and the provisional main injection period TQMF are calculated as shown by broken lines, but the pilot injection fuel pressure NPCP
n, the main injection fuel pressure NPCMn is taken in, and the pilot injection period TQPF and the main injection period TQMF are calculated to be corrected as shown by the solid line. Therefore, the fuel of the command injection amount QFIN calculated by the process at step 110 can be injected regardless of the transition, and the error between the command injection amount QFIN and the actual injection amount can be reduced.

Further, due to the characteristics of the injection control solenoid valve 3, particularly the influence of residual magnetism, as shown in FIG. 12, when the interval TINT becomes short, the injection delay time TDM changes rapidly. That is, at the time of rotation fluctuation and transition, the electronic control circuit 1
When the actual interval TINT becomes smaller than the interval TINT calculated in step 1, the injection amount sharply increases. This is because the main injection period TQMF is the same.

Therefore, in the present embodiment, as described above, the surplus angle control and the time control are switched according to the size of the interval TINT. As shown in FIG. 11, the pilot injection timing pulse number CNECAPF and the main injection timing pulse number CNECAMF are the same,
By controlling the energization start by the main injection time excess time TTMF, the fluctuation of the interval TINT due to the rotation fluctuation can be suppressed, and the rapid change of the injection amount can be suppressed.

Further, as shown in FIG. 10, the remainder angle control is performed, and the injection timing is separately controlled by the pilot injection timing pulse number CNECAPF and the main injection timing pulse number CNECAMF according to the pulse number. According to the remainder angle control, there is a rotation fluctuation during that time, and if the Ne pulse width from the rotation speed sensor 12 fluctuates, the actual interval is greatly affected. However, the influence of the actual injection timing on the top dead center TDC is small.

On the other hand, as shown in FIG. 11, time control is performed to control the number of pilot injection timing pulses CNECAPF and the number of main injection timing pulses CNECAMF to be the same. According to this time control, the rotation fluctuates before the energization starts, and if the Ne pulse width from the rotation speed sensor 12 fluctuates, the influence on the actual interval is small. But,
The influence of the actual injection timing on the top dead center TDC is large.

As described above, the present invention is not limited to such embodiments at all, and can be implemented in various modes without departing from the gist of the present invention.

[0056]

As described in detail above, the accumulator type fuel injection device of the present invention takes in the fuel pressure during injection and calculates the injection period, so that the injection period is calculated based on the actual fuel pressure during injection. It is possible to reduce the error between the calculated injection amount and the actual injection amount regardless of the transition.
Also, if the tentative injection period is calculated and the fuel pressure during injection is detected normally, and the injection period is calculated again, the injection amount may suddenly change even if the detection is not performed normally. There is no.

Further, at the time of each injection of the multi-injection, the fuel pressure during the injection is taken in and the injection period is calculated, so that the error between the injection amount calculated for each injection and the actual injection amount can be reduced. By switching the control in accordance with the interval by the switching means, it is possible to suppress the variation of the interval due to the rotation variation.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a pressure accumulating fuel injection device as one embodiment of the present invention.

FIG. 2 is a flowchart illustrating an example of a fuel injection control process performed in the electronic control circuit according to the embodiment.

FIG. 3 is a flowchart illustrating a first half of a multi-injection control process performed in the electronic control circuit according to the embodiment.

FIG. 4 is a flowchart showing a latter half of a multi-injection control process performed in the electronic control circuit of the embodiment.

FIG. 5 is a timing chart of fuel injection performed by the pressure accumulating fuel injection device of the present embodiment.

FIG. 6 is a graph showing a relationship between an estimated pressure and an injection delay time in the present embodiment.

FIG. 7 is a graph showing a relationship between an injection period, a fuel pressure, and a command injection amount according to the embodiment.

FIG. 8 is a graph showing a relationship among a rotation speed, an injection amount, and an interval according to the embodiment.

FIG. 9 is a graph illustrating switching between the surplus angle control and the time control according to the embodiment.

FIG. 10 is a timing chart of multi-injection at the time of surplus angle control performed in the pressure accumulating fuel injection device of the present embodiment.

FIG. 11 is a timing chart of multi-injection at the time of time control performed by the pressure accumulating fuel injection device of the present embodiment.

FIG. 12 is a graph showing a relationship between an interval and an injection delay time in the present embodiment.

FIG. 13 is a timing chart of a conventional multi-injection.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 2 ... Injector 3 ... Injection control solenoid valve 4 ... Accumulation piping 6 ... Supply piping 7 ... High pressure supply pump 8 ... Fuel tank 9 ... Fuel supply pump 10 ... Discharge amount control device 11 ... Electronic control circuit 12 ... Rotation Number sensor 13 ... accelerator opening sensor 14 ... pressure sensor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 45/00 364 F02D 45/00 364P F02M 47/00 F02M 47/00 P 55/02 350 55/02 350E F-term (reference) 3G066 AA07 AB02 AC09 AD12 BA08 BA12 BA19 BA51 CB01 CB09 CB12 CC06T CC14 CC67 CC68U CD25 CD26 CE13 CE22 DA01 DA04 DA09 DC04 DC09 DC13 DC14 DC18 DC19 3G084 AA01 BA13 BA15 DA04 EB09 EB12 EC01 FA03 FA01 FA03 FA01 FA10 HA02 JA11 LB11 LC01 MA11 MA18 MA23 NA06 NB06 NC02 PA07Z PA10Z PB03A PB05A PB08Z PE01Z PE08Z PF03Z

Claims (5)

[Claims] An injector is provided for each cylinder of an internal combustion engine and injects fuel into the cylinder, a pressure accumulating pipe for holding fuel supplied at a high pressure and supplying the fuel to the injector, and detecting a fuel pressure of the pressure accumulating pipe. In a pressure accumulating type fuel injection device, comprising: fuel pressure detecting means; and control means for performing fuel injection control by the injector based on the fuel pressure; wherein the control means detects the fuel pressure of the injector based on the detected fuel pressure. A pressure accumulation type wherein an injection timing is calculated, an injection fuel pressure of the pressure accumulation pipe is detected when the injection timing is reached, and an injection period at that time is calculated based on the injection fuel pressure. Fuel injection device. 2. The control means calculates an injection timing of the injector based on the detected fuel pressure, and calculates a tentative injection period. 2. The fuel injection system according to claim 1, wherein the fuel pressure is detected, and when the fuel pressure during injection is detected normally, the injection period at that time is recalculated based on the fuel pressure during injection. Accumulator type fuel injection device. 3. The control means also detects the fuel pressure during injection of the accumulator pipe at each of the injection timings during each of the multiple injections, and based on the fuel pressure during injection at that time. 3. The accumulator type fuel injection device according to claim 1, wherein an injection period is calculated. 4. The control means calculates a command injection amount based on an operation state, calculates an injection timing of the injector based on the detected fuel pressure, and when the injection timing is reached. 4. The accumulator according to claim 1, wherein the fuel pressure at the time of injection of the pressure accumulating pipe is detected, and the injection period at that time is calculated from the command injection amount based on the fuel pressure at the time of injection. Fuel injection device. 5. The accumulator according to claim 1, wherein said control means includes a switching means for switching calculation of an injection timing of a main injection based on a fuel injection interval in a multi-injection. Type fuel injection device.