JP4269484B2 - Accumulated fuel injection system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pressure-accumulation fuel injection device that injects high-pressure fuel stored in a common rail from an injector to a diesel engine.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an accumulator type fuel injection device used in a diesel engine detects a fuel pressure of a common rail and calculates an injection timing and an injection period (an energization period for the injector) based on the fuel pressure. However, the fuel pressure of the common rail fluctuates due to fuel pumping from a high-pressure pump, etc. Especially during transients such as acceleration, the fuel pressure at the time of detection differs greatly from the fuel pressure at the time of injection. An error occurs between the command injection amount and the actual injection amount by the injector.
Therefore, in the accumulator fuel injection device described in Japanese Patent Application No. 11-326911, the injection timing of the injector is calculated based on the fuel pressure of the common rail, and the fuel pressure of the common rail is detected again when the injection timing comes. The injection period of the injector is calculated based on the fuel pressure.
[0003]
[Problems to be solved by the invention]
However, when the fuel pressure is detected and the calculation of the injection period is completed, a time of about 50 to 200 μs is required in the case of using a general 32-bit MPU currently on the market. Therefore, even if “the fuel pressure is detected when the injection timing is reached”, it is actually necessary to detect the fuel pressure to some extent before the point at which injection is started from the injector. In this case, the following problems occur.
If fuel is being pumped from the high-pressure pump during fuel injection from the injector, the fuel pressure at the injection timing becomes higher than the fuel pressure detected at the start of energization of the injector, and the injection amount increases. That is, because the fuel pressure is detected low, the injection period is longer than the normal value.
[0004]
Also, the fuel pressure (average injection pressure) during the injection period is the same when the fuel pressure of the high pressure pump and the injection of the injector overlap and when the fuel pressure at the start of energization to the injector is the same. Because of the difference, the injection amount increases when the fuel pumping of the high-pressure pump and the injection of the injector overlap.
The present invention has been made based on the above circumstances, and its purpose is to provide an accumulator fuel that can reduce the error between the command injection amount and the actual injection amount even when the injection of the injector and the pumping of the high pressure pump overlap. It is in providing an injection device.
[0005]
[Means for Solving the Problems]
(Means of Claim 1)
A first injection condition for injecting fuel from the injector while the high-pressure pump stops pumping fuel, and a second injection condition for injecting fuel from the injector while the high-pressure pump pumps fuel are: The pressure accumulation type fuel injection apparatus that is set, and the control means for controlling the operation of the injector performs injection from the injector under the first injection condition when controlling the operation of the injector under the second injection condition. Expecting the change in the pressure drop rate during the injection period and the pressure drop rate during the injection period in which injection is performed from the injector under the second injection condition, the expected injection pressure of the injector at the command injection timing is obtained, and the expected injection The injection period of the injector is calculated based on the pressure and the command injection amount.
[0006]
Under the second injection condition, since the injection of the injector and the pumping of the high pressure pump overlap, the pressure drop rate during the injection period is smaller than the pressure drop rate when the injection is performed under the first injection condition. Accordingly, by calculating the expected injection pressure in consideration of the change in the pressure drop rate under the first injection condition and the pressure drop rate under the second injection condition, the injector can be operated at an injection pressure higher than the actual injection pressure. The injection period can be calculated. As a result, since the injection period can be brought close to a normal value, the error between the actual injection amount and the command injection amount can be reduced.
[0007]
Further, the control means takes in the fuel pressure PC in the common rail before the command injection timing, and uses the fuel pressure PC as a reference and the average injection pressure during the injection period in which the injection is performed from the injector under the first injection condition. The pressure difference ΔPCM with respect to the average injection pressure during the injection period in which injection is performed from the injector under the injection condition 2 is obtained, and the estimated injection pressure is calculated by adding the pressure difference ΔPCM to the fuel pressure NPCMn at the start of energization of the injector. ing.
[0008]
This is because the amount of change between the pressure drop rate under the first injection condition and the pressure drop rate under the second injection condition is equal to the average injection pressure during the injection period performed under the first injection condition and the second This is because the difference from the average injection pressure during the injection period performed under the injection conditions, that is, the pressure difference ΔPCM can be considered .
[0009]
(Means of Claim 2 )
In the pressure accumulation type fuel injection device according to claim 1 ,
The control means uses at least one of the command injection amount, the fuel pressure in the common rail, and the rotational speed of the internal combustion engine as a parameter, and obtains a relationship between this parameter and the pressure difference ΔPCM in advance, and has a map storing the correlation. The pressure difference ΔPCM is obtained from this map based on the parameters. In this case, ΔPCM does not need to be obtained by calculation, and can be obtained from the map. Therefore, the processing procedure of the control means can be simplified, and the injection period of the injector can be calculated in a shorter time.
[0010]
(Means of claim 3 )
In the pressure accumulation type fuel injection device according to claim 1 or 2 ,
The control means calculates an energization start timing for the injector in consideration of an injection delay time from when the injector is energized until the actual injection is started, and takes in the fuel pressure PC at the energization start timing.
[0011]
(Means of claim 4 )
In the pressure accumulation type fuel injection device according to claim 1 or 2 ,
The control means requires a predetermined time t in order to calculate the injection period, and takes in the fuel pressure PC more than the predetermined time t before the command injection timing.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Next, the pressure accumulation type fuel injection device of the present invention will be described based on the drawings.
(First embodiment)
FIG. 1 is a schematic diagram showing the overall configuration of the pressure accumulation type fuel injection device 1.
An accumulator fuel injection device 1 of this embodiment is used for a four-cylinder diesel internal combustion engine (hereinafter referred to as an engine 2). As shown in FIG. 1, a feed pump 4 for pumping fuel from a fuel tank 3; The high pressure pump 5 that pressurizes and pumps the pumped fuel, the common rail 6 that accumulates the high pressure fuel pumped from the high pressure pump 5, and the common rail 6 connected via the injection pipe 7. It comprises an injector 8 attached to each cylinder, an electronic control device (hereinafter referred to as ECU 9) for controlling the operation of the system, and the like.
[0013]
As shown in FIG. 2, the high-pressure pump 5 includes a cam shaft 10 that rotates in synchronization with the rotation of the engine 2, a plunger 12 that reciprocates in the cylinder 11 as the cam shaft 10 rotates, A low-pressure passage 14 communicating with the pump chamber 13 formed in the above, and an electromagnetic valve 15 for opening and closing the low-pressure passage 14 are provided. In the high-pressure pump 5, when the electromagnetic valve 15 is energized during the pressure-feeding stroke of the plunger 12 and closes the low-pressure passage 14, the fuel in the pump chamber 13 is pressurized, and the fuel pressure opens the check valve 16. When the pressure exceeds the pressure, the high pressure fuel pushes the check valve 16 open and is pumped from the high pressure pipe 17 to the common rail 6. The high-pressure pump 5 pumps twice at an interval of 360 ° CA during one combustion stroke (720 ° CA) of the engine 2.
[0014]
The injector 8 injects high-pressure fuel supplied from the common rail 6 into the cylinder of the engine 2, and a pressure control chamber in which the fuel pressure of the common rail 6 acts on the back pressure side of a needle (not shown) that opens and closes the injection hole. (Not shown) is provided, and an electromagnetic valve 18 is provided between the pressure control chamber and the low pressure side. When the solenoid valve 18 is closed, the needle closes the nozzle hole under the fuel pressure in the pressure control chamber. When the solenoid valve 18 is opened, the fuel in the pressure control chamber flows to the low pressure side. Fuel injection is performed by lifting and opening the nozzle hole. The injector 8 of each cylinder performs injection in the order of first cylinder-third cylinder-fourth cylinder-second cylinder.
[0015]
The ECU 9 includes a rotational speed sensor 19 that detects the engine rotational speed, an accelerator opening sensor 20 that detects the amount of depression of the accelerator pedal (accelerator opening), a fuel pressure sensor 21 that detects the fuel pressure in the common rail 6, and a coolant temperature. Then, signals from various sensors 22 for detecting the intake air temperature, intake air pressure, etc. are input, the discharge amount of the high-pressure pump 5, the injection timing and the injection amount of the injector 8 are calculated based on these signals, and the electromagnetic wave is calculated according to the calculation results. Control signals for the valve 15 and the electromagnetic valve 18 are output.
[0016]
In the present system, the high pressure pump 5 is driven twice during one combustion stroke of the engine 2, and the injection of the injector 8 may or may not overlap during the pumping period of the high pressure pump 5. In this embodiment, the injection of the injector 8 to the first cylinder and the fourth cylinder is performed during the pumping period of the high-pressure pump 5, and the injection of the injector 8 to the second cylinder and the third cylinder is performed during the pumping stop period of the high-pressure pump 5. Shall be performed. In the following description, the case where the injection is performed during the pumping stop period of the high pressure pump 5 is referred to as a first injection condition, and the case where the injection is performed during the pumping period of the high pressure pump 5 is referred to as the second injection condition.
[0017]
Next, the processing procedure of the ECU 9 related to the fuel injection control of this system will be described based on the flowcharts shown in FIGS. 3 and 4 and FIGS.
Step 100 ... The rotational speed NE is taken in based on the detection signal of the rotational speed sensor 19, and the accelerator opening degree Accp is taken in based on the detection signal of the accelerator opening degree sensor 20.
Step 110 ... Based on the rotational speed NE and the accelerator opening degree Accp, a command injection amount QFIN is calculated using a characteristic map (not shown) for calculating the injection amount.
Step 120 ... Based on the rotational speed NE and the command injection amount QFIN, a command injection timing TFIN is calculated using a characteristic map (not shown) for calculating the injection timing.
[0018]
Step 130... Take in the fuel pressure NPCn of the common rail 6 based on the detection signal of the fuel pressure sensor 21 at a predetermined timing (see FIG. 5). Note that the subscript n indicates the amount detected in the current process.
Step 140 ... The expected pressure NPCF is calculated from the fuel pressure NPCn taken in Step 130 based on the following equation. Here, NPCn-1 is the fuel pressure taken in at the previous Step 130, and NPCMn-1 is the fuel pressure at the start of injector energization taken in the previous Step 230 (described later).
[0019]
NPCF ← NPCn + ΔPC
ΔPC ← NPCMn-1 -NPCN-1
Here, the pressure difference ΔPC between the previous NPCn-1 and the previous NPCMn-1 is generated in substantially the same manner during the current process regardless of whether the vehicle is in steady running or in a transient state. NPCF is calculated to reduce the error during the current injection.
[0020]
Step 150 ... Based on the expected pressure NPCF calculated in Step 140, the injection delay time TDM is calculated from the characteristic map shown in FIG. As shown in FIG. 5, the injection delay time TDM is the time from when the solenoid valve 18 of the injector 8 is energized until the fuel is actually injected. The injector 8 is configured to lift and open the needle under the action of the supplied fuel pressure, so that the injection delay time varies depending on the fuel pressure. The characteristic map is preferably created by previously obtaining the relationship between the fuel pressure and the injection delay time through experiments or the like.
[0021]
Step 160 ... The injector energization start timing is calculated based on the command injection timing TFIN calculated in Step 120 and the injection delay time TDM calculated in Step 150. As shown in FIG. 5, the injector energization start timing includes the injection timing pulse number CNECAMF from the control reference position detected by the NE pulse to immediately before the start of injector energization, and the remaining time TTMF from this pulse to the start of injector energization. It consists of.
Z ← (A-TFIN) / X
TTMF ← (Z / X) × TDM
CNECAMF ← (A-TFIN-Z) / X
[0022]
If TTMF <0, the following processing is performed.
TTMF ← TTMF + Y
CNECAMMF ← CNECAMF-1
Here, “CNECAMF” is an integer, and “Z” is a remainder. “A” is an angle from the control reference position to the top dead center TDC, and “X” is an angle corresponding to one pulse output from the rotation speed sensor 19. “Y” is the time required to rotate the angle X at the rotational speed at that time.
[0023]
Step 170... The temporary injection period TQMF is calculated from the characteristic map shown in FIG. 7 based on the command injection amount QFIN and the estimated pressure NPCF.
Step 180 ... Cylinder determination is performed by the cylinder determination counter CCYLN. The counter CCYLN is counted up from “0” to “3” every 180 ° CA, and returns to “0” at 720 ° CA. In this determination, if the counter value is “0” or “2”, that is, the first cylinder or the fourth cylinder, the process proceeds to Step 190, and if the counter value is “1” or “3”, that is, the second cylinder or In the case of the third cylinder, the process proceeds to Step 200.
[0024]
Step190 ... In the case of the first cylinder or the fourth cylinder, as shown in FIG. 5, since the injection of the injector 8 is performed during the pumping period of the high-pressure pump 5 (second injection condition), the pressure change due to pump pumping Therefore, it is necessary to obtain the fuel pressure at the start of injection (expected injection pressure of the injector 8). Therefore, first, a difference ΔPCM between the fuel pressure at the start of energization of the injector 8 and the expected injection pressure of the injector 8 is calculated. This ΔPCM can be obtained based on the following basic formula (1) representing the pressure change.
ΔPC = (Δq / V) × E ………………………… (1)
Δq: amount entering / leaving into the high-pressure vessel V: high-pressure volume E: bulk modulus (Young's modulus)
[0025]
Since ΔPCM is a difference in average injection pressure between when injection and pressure feeding do not overlap, Δq can be obtained as follows.
a) If the amount of change when the injection does not overlap with pumping is Δq1,
Δq1 = 0− (injection amount / 2) + leakage amount b) If Δq2 is the amount of change when the injection overlaps with the pumping,
Δq2 = pump pumping amount− (injection amount / 2) + leakage amount.
Since Δq = Δq2−Δq1, Δq = pump pumping amount (Qd).
[0026]
Here, if the pump pumping amount after the start of injector energization (point A in FIG. 5) is Qa and the pump pumping amount after the center of the injection period (point B in FIG. 5) is Qb, the pump that affects ΔPCM. The pumping amount Qd can be obtained by Qd = Qa−Qb.
Applying the above together to the basic equation (1), ΔPCM can be calculated by the following equation (2).
ΔPCM = (Qd / V) × E …………………… (2)
In the equation (2), V is a volume including the common rail 6 and the injection pipe 7 and is a fixed value, and E (volume elastic modulus of light oil) can be obtained from the taken fuel pressure NPCn.
After calculating ΔPCM, the process proceeds to the next Step 200.
[0027]
Step 200 ... It is determined based on a signal from the rotational speed sensor 19 whether or not it is a reference position for control. When it is not the reference position (determination result NO), it waits until it reaches the reference position, and when it becomes the reference position (determination result YES), it proceeds to the next Step 210.
Step 210 ... The number of pulses output from the rotation speed sensor 19 is counted.
Step 220 ... It is determined whether or not the counted pulse number coincides with the injection timing pulse number CNECAMF obtained in Step 160. When it does not coincide with the injection timing pulse number CNECAMF (determination result NO), it waits until it coincides with the injection timing pulse number CNECAMF, and when it coincides with the injection timing pulse number CNECAMF (determination result YES), it proceeds to the next Step 230. move on.
[0028]
Step 230 ... It is determined whether or not the extra time TTMF obtained in Step 160 has elapsed. When the surplus time TTMF has not elapsed (determination result NO), the process waits until the surplus time TTMF elapses, and when the surplus time TTMF has elapsed (determination result YES), the process proceeds to the next Step 240.
Step 240 ... Energization of the injector 8 (solenoid valve 18) is started. As a result, the needle of the injector 8 is lifted and injection is started when the injection delay time TDM has elapsed since the energization.
[0029]
Step 250 ... The fuel pressure (NPCMn) in the common rail 6 is taken in when the injector 8 is energized.
Step 260 ... It is determined whether or not the absolute value of the difference between the fuel pressure NPCMn taken in and the fuel pressure NPCn taken in Step 130 is greater than or equal to a predetermined value α. When the determination result is NO, that is, when the absolute pair is smaller than the predetermined value α, it is determined that the fuel pressure NPCMn taken at the start of energization of the injector 8 is taken in normally without being affected by noise or the like. Then, go to the next Step270. On the other hand, if the determination result is YES, that is, if the absolute value is greater than or equal to the predetermined value α, it is determined that the fuel pressure NPCMn taken at the start of energization of the injector 8 is an abnormal value affected by noise, etc. Proceed to Step 310.
[0030]
Step270 ... Cylinder determination is performed by the cylinder determination counter CCYLN. In this determination, if the counter value is “0” or “2”, that is, if it is the first cylinder or the fourth cylinder, the process proceeds to Step 290. If the counter value is “1” or “3”, that is, the second cylinder or For the third cylinder, go to Step 280.
Step 280 ... In the case of the second cylinder or the third cylinder, since the injection of the injector 8 is performed during the pumping stop period of the high pressure pump 5 (first injection condition), the fuel pressure NPCMn at the start of energization of the injector taken in Step 250 Is set as the final injection pressure NPCMFn, and the process proceeds to Step 300.
[0031]
Step 290 ... In the case of the first cylinder or the fourth cylinder, since the injection of the injector 8 is performed during the pumping period of the high pressure pump 5 (second injection condition), the fuel pressure NPCMn at the start of energization taken in Step 250 is set to Step 190 The expected injection pressure is calculated by adding the average injection pressure difference ΔPCM calculated in step S1, and the expected injection pressure is set as the final injection pressure NPCMFn.
Step 300 ... Based on the final injection pressure NPCMFn set in Step 280 or Step 290 and the command injection amount QFIN calculated in Step 110, the injection period TQMF is calculated again from the characteristic map shown in FIG.
[0032]
Step 310 ... The temporary injection period TQMF calculated in Step 170 is directly adopted as the injection period, and the process proceeds to the next Step 320.
Step 320 ... It is determined whether or not the injection period TQMF has elapsed. When the injection period TQMF has not elapsed (determination result NO), the process waits until the injection period TQMF elapses. When the injection period TQMF has elapsed (determination result YES), the process proceeds to the next Step 330.
Step 330 ... End energization of the injector 8 (solenoid valve 18). As a result, the needle of the injector 8 receives the fuel pressure in the pressure control chamber and moves in the valve closing direction, shuts off the fuel passage leading to the injection hole, and ends the injection.
[0033]
(Effect of this embodiment)
In the second injection condition, the system changes the pressure drop rate during the injection period in which injection is performed under the first injection condition and the pressure drop rate during the injection period in which injection is performed under the second injection condition. Expecting (ΔPCM), the expected injection pressure of the injector 8 at the command injection timing TFIN (at the start of injection) is obtained, and the injection period TQMF of the injector 8 is calculated based on the estimated injection pressure and the command injection amount QFIN. . In this case, the injection period TQMF of the injector 8 can be calculated with an injection pressure higher than the actual injection pressure, and the injection period TQMF can be made to coincide with a substantially normal value, so that the actual injection amount and the command injection amount QFIN The error can be reduced.
[0034]
(Second embodiment)
In the above embodiment, ΔPCM is obtained by calculation when injection is performed under the second injection condition. However, ΔPCM can also be obtained from a map in order to reduce the calculation load of the ECU 9.
An example thereof will be described with reference to FIGS.
FIG. 8 is a flowchart showing the processing procedure of the ECU.
Step 400: The pressure change amount (ΔPCMBAS) at the predetermined rotational speed NB1 is obtained from the map shown in FIG. 9 based on the command injection amount QFIN and the estimated pressure NPCF.
Here, the map shown in FIG. 9 shows the correlation between QFIN, NPCF, and ΔPCMBAS, and is created by obtaining the relationship between the three in advance through experiments or the like.
[0035]
Step 410: Since the high-pressure pump 5 of the present invention is driven in synchronization with the engine rotation, the pump oil feed rate is high when the engine speed is high, and the pump oil feed rate is low when the engine speed is low. However, since the pressure change amount ΔPCMBAS obtained from the map of FIG. 9 does not include the engine speed as a parameter, it is necessary to perform correction based on the engine speed. Therefore, the correction coefficient KNEPCM is obtained based on the engine speed NE from the map shown in FIG.
Step 420... ΔPCM is obtained by multiplying ΔPCMBAS obtained in Step 400 by KNEPCM obtained in Step 410.
[0036]
In this embodiment, since it is not necessary to obtain ΔPCM by calculation, it is also possible to obtain ΔPCM after taking in the fuel pressure NPCMn at the start of energization in Step 250. In this case, the parameter used in the map of FIG. 9 is not the expected pressure NPCF, but the fuel pressure NPCMn at the start of energization taken in Step 250 can be used.
The map of FIG. 9 represents the relationship between QFIN, NPCF, and ΔPCMBAS. At least one of the command injection amount, the fuel pressure in the common rail, and the engine speed is used as a parameter. It is also possible to create a map by obtaining the relationship in advance and use other parameters as correction coefficients.
[0037]
(Other examples)
In the first embodiment, the injection period TQMF is calculated from one characteristic map. However, even if the final injection pressure NPCMFn is the same, when the pumping of the high-pressure pump 5 and the injection of the injector 8 overlap, the characteristic is calculated. The map itself changes. Therefore, the characteristic map may be switched between when the high pressure pump 5 and the injection of the injector 8 overlap and when they do not overlap. For example, in the four-cylinder engine 2 described in the first embodiment, when the pumping and the injection overlap each other, the time when they do not overlap occurs alternately, so that the injection period TQMF can be calculated by alternately switching the two characteristic maps for each injection. It ’s fine.
[0038]
In the first embodiment, the fuel pressure NPCMn is taken in at the start of energization of the injector 8 (Step 250), and ΔPCM is added to the fuel pressure NPCMn to obtain the expected injection pressure (in the case of the second injection condition). When the ECU 9 needs the predetermined time t to calculate the injection period TQMF, the fuel pressure PC is set to a predetermined time or a predetermined angle before the start of energization if the predetermined time t is more than the predetermined time t from the command injection timing. It may be imported.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an overall configuration of an accumulator fuel injection device.
FIG. 2 is a schematic diagram showing a configuration of a high-pressure pump.
FIG. 3 is a flowchart showing a processing procedure of an ECU related to fuel injection control.
FIG. 4 is a flowchart showing a processing procedure of an ECU related to fuel injection control.
FIG. 5 is a time chart relating to fuel injection control of the present system.
FIG. 6 is a map showing the relationship between expected pressure and injection delay time.
FIG. 7 is a map showing a relationship between an injection period and a command injection amount.
FIG. 8 is a flowchart showing a processing procedure of the ECU for obtaining ΔPCM.
FIG. 9 is a map showing the relationship between ΔPCM, command injection amount, and expected pressure at a predetermined rotational speed.
FIG. 10 is a map for determining a correction coefficient based on the engine speed.
[Explanation of symbols]
1 Accumulated fuel injection system 2 Engine (internal combustion engine)
5 High-pressure pump 6 Common rail 8 Injector 9 ECU (control means, injection amount calculation means, injection timing calculation means)
19 Rotational speed sensor (operating state detection means)
20 Accelerator opening sensor (operating state detection means)
21 Fuel pressure sensor (Fuel pressure detection means)

Claims (4)

A high-pressure pump that pressurizes and pumps fuel; and
A common rail for accumulating high-pressure fuel pumped from this high-pressure pump;
An injector that opens when energized, and injects high-pressure fuel supplied from the common rail into the cylinder of the internal combustion engine during the valve opening period;
Fuel pressure detecting means for detecting the fuel pressure in the common rail;
An operating state detecting means for detecting an operating state of the internal combustion engine;
An injection amount calculating means for calculating a command injection amount of the injector from an operating state of the internal combustion engine;
Injection timing calculating means for calculating a command injection timing of the injector based on the rotational speed of the internal combustion engine and the command injection amount;
Control means for controlling the operation of the injector,
A first injection condition for injecting fuel from the injector while the high-pressure pump stops pumping fuel; and a second injection condition for injecting fuel from the injector while the high-pressure pump is pumping fuel. An accumulator fuel injection device in which injection conditions are set,
The control means includes
When controlling the operation of the injector under the second injection condition,
Expecting a change between a pressure drop rate during an injection period in which injection is performed from the injector under the first injection condition and a pressure drop rate during an injection period in which injection is performed from the injector under the second injection condition. The expected injection pressure of the injector at the commanded injection timing is obtained, and the injection period of the injector is calculated based on the estimated injection pressure and the commanded injection amount .
The fuel pressure PC in the common rail is taken before the command injection timing,
The change is obtained with reference to the fuel pressure PC. The injection is performed from the injector under the average injection pressure during the injection period in which the injection is performed from the injector under the first injection condition and the second injection condition. The pressure difference ΔPCM from the average injection pressure during the injection period
The accumulator fuel injection apparatus , wherein the estimated injection pressure is calculated by adding the pressure difference ΔPCM to a fuel pressure NPCMn at the start of energization of the injector . In the pressure accumulation type fuel injection device according to claim 1,
The control means includes
Using at least one of the command injection amount, the fuel pressure in the common rail, and the rotational speed of the internal combustion engine as a parameter, a relationship between this parameter and the pressure difference ΔPCM is obtained in advance, and a map storing the correlation is provided. And the pressure difference ΔPCM is obtained from the map based on the parameter . In the pressure accumulation type fuel injection device according to claim 1 or 2 ,
The control means includes
In consideration of an injection delay time from when the injector is energized to when the injection is actually started, an energization start timing for the injector is calculated, and the fuel pressure PC is taken in at the energization start timing. Accumulated fuel injection system. In the pressure accumulation type fuel injection device according to claim 1 or 2 ,
The control means includes
A pressure accumulating fuel injection device that requires a predetermined time t to calculate the injection period and takes in the fuel pressure PC at least a predetermined time t before the command injection timing .

Images