JP5630464B2 - Fuel injection control device - Google Patents

Description

  The present invention relates to a fuel injection control device applied to a fuel injection system that uses a metering valve to meter a pumping amount of a high-pressure pump that pressurizes and pumps fuel supplied from an electric low-pressure pump.

  Conventionally, a high-pressure pump that pressurizes and feeds fuel supplied from an electric low-pressure pump is metered by a metering valve, and fuel pressurized by a high-pressure pump is accumulated in a pressure accumulating chamber and then fed from a fuel injection valve. A fuel injection system that injects fuel is known (for example, see Patent Document 1). The metering method of the pumping amount includes the suction metering method in which the amount of suction to the high-pressure pump is controlled by the metering valve, and the pressurization start timing in the pumping stroke is controlled by the metering valve. One of the discharge metering methods for metering the pumping amount is adopted.

  In such a fuel injection system, the fuel pressure in the accumulator of the high-pressure system is detected by a pressure sensor, and the energization to the metering valve is feedback-controlled based on the differential pressure between the detected actual pressure and the target pressure, and the high-pressure pump The actual pressure is made to follow the target pressure by metering the amount of pumping.

JP 2010-255544 A

  In the case of the discharge metering method, the metering valve is set to the target pressurization start timing due to the error in the mounting angle of the high-pressure pump and the variation in the response of the metering valve to the energization control due to machine differences and changes over time. Even if energization control is performed, the pressurization start timing may be shifted. When the pressurization start timing is shifted, the pumping amount of the high-pressure pump is shifted from the target pumping amount.

  When the pumping amount of the high-pressure pump is metered by feedback control of energization to the metering valve based on the differential pressure between the actual pressure of the high-pressure system and the target pressure, the pumping amount of the high-pressure pump deviates from the target pumping amount. As a result, the responsiveness of the actual pressure following the target pressure decreases.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a fuel injection control device that accurately adjusts the pumping amount of a high-pressure pump to a target pumping amount and a fuel injection system using the same. And

  In a fuel injection system that controls the pressurization start timing of pressurization with a high pressure pump with a metering valve to meter the pumping amount of the high pressure pump, pressurization is performed while the metering valve is open during the pumping stroke of the high pressure pump. When the fuel in the chamber is returned to the low-pressure system and the metering valve is closed, pressurization of the fuel in the pressurizing chamber is started to meter the pumping amount of the high-pressure pump.

  In this metering method, the fuel pressure in the low pressure system is low in the intake stroke where the metering valve is opened and fuel is sucked into the high pressure pump from the low pressure system, and the metering valve is opened in the pressure feed stroke. While the fuel in the pressurizing chamber is returned to the low pressure system, the fuel pressure in the low pressure system rises. During the pumping stroke, the metering valve is closed and the pressurized fuel is pumped to the high pressure side. The fuel pressure decreases. Therefore, if a change in the fuel pressure in the low-pressure system is detected, the pumping amount of the high-pressure pump is determined regardless of errors in the assembly angle of the high-pressure pump with respect to the engine and variations in the responsiveness of the metering valve to the energization control in the fuel injection system. The pressurizing period to be detected can be detected.

Therefore, according to the fuel injection control device of the present invention, a low-pressure fuel pressure between the electric low-pressure pump and the high-pressure pump or a detected value of a physical quantity related to the fuel pressure is acquired as an electric signal and estimated based on the detected value. The pressurization start timing is adjusted by controlling the metering valve based on the pumping amount of the high-pressure pump, and the pumping amount of the high-pressure pump is metered.
This detects the pressurization period that determines the pumping amount of the high-pressure pump regardless of the error in the assembly angle of the high-pressure pump with respect to the engine and the variation in the responsiveness of the metering valve to the energization control in the fuel injection system. By controlling the metering valve based on the pumping amount of the high-pressure pump estimated based on the period and adjusting the pressurization start timing, the pumping amount of the high-pressure pump can be accurately metered to the target pumping amount.

  The functions of the plurality of means provided in the present invention are realized by hardware resources whose functions are specified by the configuration itself, hardware resources whose functions are specified by a program, or a combination thereof. The functions of the plurality of means are not limited to those realized by hardware resources that are physically independent of each other.

The block diagram which shows the fuel-injection system by this embodiment. The schematic diagram which shows the structure of a high pressure pump. The time chart which shows the relationship between metering valve current, low pressure pump drive current, low pressure fuel pressure, and cam lift. The flowchart which shows the pumping amount control process 1 of a high pressure pump. The flowchart which shows the pumping amount control process 2 of a high pressure pump.

(Fuel injection system)
A fuel injection system 2 shown in FIG. 1 is for injecting fuel into, for example, a multi-cylinder diesel engine for automobiles (hereinafter also simply referred to as “engine”). The fuel injection system 2 is mainly composed of a feed pump (FP) 12, a high-pressure pump 20, a common rail 40, a fuel injection valve 50, and an electronic control unit (ECU) 60. Yes. In FIG. 1, only the fuel injection valve 50 corresponding to one cylinder among the plurality of cylinders is illustrated, and illustration of the fuel injection valves 50 of other cylinders is omitted.

  The FP 12 is an electric pump that rotates, by a motor, an impeller having a plurality of blades formed on the outer periphery of a disk-shaped rotating body. The FP 12 sucks the fuel in the fuel tank 10 and supplies it to the high-pressure pump 20 side as the impeller rotates. The FP 12 is directly connected to the battery and supplied with a drive current. Therefore, if the rotation speed of the FP 12 is constant, the drive current of the FP 12 is substantially constant.

  As shown in FIG. 2, the high-pressure pump 20 sucks fuel supplied from the FP 12 through the low-pressure pipe 100 into the pressurizing chamber 200 by reciprocating the plunger 22 as the camshaft cam rotates. This is a known pump for pressurization.

  When the energization is turned off, the metering valve 24 is opened and the fuel inlet 26 is opened. As a result, the low pressure pipe 100 and the pressurizing chamber 200 communicate with each other in the suction stroke in which the plunger 22 descends from the top dead center toward the bottom dead center, and fuel is sucked into the pressurizing chamber 200.

  When the energization is turned on, the metering valve 24 is closed and the fuel inlet 26 is closed. In the pressure feed stroke in which the plunger 22 rises from the bottom dead center toward the top dead center, the metering valve 24 closes, the fuel inlet 26 is closed, and the communication between the low pressure pipe 100 and the pressurizing chamber 200 is shut off. Pressurization of the fuel in the pressurizing chamber 200 is started.

  The discharge valve 28 is opened when the fuel in the pressurizing chamber 200 is pressurized and exceeds a predetermined valve opening pressure, and the fuel in the pressurizing chamber 200 is pumped to the high-pressure pipe 104. Therefore, the pumping amount of the high-pressure pump 20 is determined by the amount of fuel remaining in the pressurizing chamber 200 when the metering valve 24 is closed. In other words, the pumping amount of the high-pressure pump 20 is determined by the pressurization start timing at which the metering valve 24 is closed in the pumping stroke.

  The regulating valve 30 shown in FIG. 1 is installed in a pipe connecting a low-pressure pipe 100 that supplies fuel from the FP 12 to the high-pressure pump 20 and a return pipe 102 that returns surplus fuel from the high-pressure pump 20 to the fuel tank 10. Yes. The regulator valve 30 is opened at a predetermined valve opening pressure, whereby excess fuel in the low pressure pipe 100 is returned from the return pipe 102 to the fuel tank 10. Thereby, the fluctuation | variation of the fuel pressure of the low pressure piping 100 between the regulator valve 30 and the high pressure pump 20 is suppressed.

  In the configuration using the discharge metering type metering valve 24 that determines the pressurization start timing by metering the metering valve 24 as in the present embodiment and metering the pumping amount of the high pressure pump 20, the high pressure The fuel pressure of the low pressure system upstream of the pump 20 only needs to be equal to or higher than the pressure at which the fuel corresponding to the capacity of the pressurizing chamber 200 can be sucked in the suction stroke, and therefore, compared with a configuration using a suction metering type metering valve. The valve opening pressure of the regulating valve 30 may be high, the flow rate may be small, and the opening / closing response may be slow.

  The pressure sensor 32 is installed in the low pressure pipe 100 between the regulating valve 30 and the high pressure pump 20. By installing a pressure sensor 32 between the regulating valve 30 and the high-pressure pump 20 in the immediate vicinity of the upstream side of the high-pressure pump 20, the fluctuation of the pressure due to the fuel supplied from the FP 12 is eliminated and the operation of the high-pressure pump 20 is performed. The accompanying change in fuel pressure in the low-pressure system can be detected with high accuracy by eliminating the influence of pressure attenuation as much as possible.

  The common rail 40 is a hollow member that forms a pressure accumulating chamber that accumulates fuel pumped from the high-pressure pump 20. The common rail 40 is provided with a high pressure sensor 42 for detecting the fuel pressure in the common rail.

  The ECU 60 is mainly configured by a microcomputer centering on a CPU, RAM, ROM, flash memory and the like. The ECU 60 executes the control program stored in the ROM or the flash memory, and inputs various information representing the engine operating state such as the current value of the driving current of the FP 12 and the pressure sensors 32 and 42, and the fuel injection. Various controls of the system 2 are executed.

For example, the ECU 60 controls the valve closing timing of the metering valve 24 so that the common rail pressure detected by the pressure sensor 42 becomes the target pressure, and meteres the pumping amount of the high-pressure pump 20.
Further, the ECU 60 controls the injection amount of the fuel injection valve 50, the injection timing, and the pattern of multi-stage injection that performs pilot injection, pre-injection, after-injection, post-injection after the pilot injection, and the like.

  The ECU 60 stores a so-called TQ map indicating the correlation between the pulse width (T) of the injection command signal that commands the fuel injection valve 50 and the injection amount (Q) in a ROM or flash memory for each predetermined pressure region of the common rail pressure. I remember it. Then, when the target injection amount of the fuel injection valve 50 is determined based on the engine speed and the accelerator opening, the ECU 60 refers to the TQ map of the corresponding pressure region according to the common rail pressure detected by the pressure sensor 42. The pulse width of the injection command signal for commanding the target injection amount to the fuel injection valve 50 is acquired from the TQ map.

(Operation of high-pressure pump 20)
Next, the operation of the high-pressure pump 20 and changes in the driving current of the FP 12 and the low-pressure fuel pressure accompanying the operation of the high-pressure pump 20 will be described.

  As shown in FIG. 3, the ECU 60 turns off the power supply to the metering valve 24 in the intake stroke in which the plunger 22 of the high-pressure pump 20 descends from the top dead center to the bottom dead center according to the cam profile. As a result, the fuel inlet 26 is opened, and the low-pressure fuel in the low-pressure pipe 100 is sucked into the pressurizing chamber 200 through the fuel inlet 26. At this time, the low-pressure fuel pressure detected by the pressure sensor 32 decreases.

  When the fuel pressure in the low-pressure system decreases, the force that hinders the rotation of the FP 12 decreases, so the rotation speed of the FP 12 increases and the back electromotive force generated in the motor of the FP 12 increases. As a result, the drive current flowing through the FP 12 decreases.

  In the pumping stroke in which the plunger 22 rises from the bottom dead center toward the top dead center, the ECU 60 turns off the energization to the metering valve 24 halfway. Then, the fuel in the pressurizing chamber 200 is returned from the fuel inlet 26 to the low pressure pipe 100 by the raising of the plunger 22. At this time, the low-pressure fuel pressure detected by the pressure sensor 32 increases.

  When the fuel pressure in the low-pressure system increases, the force that hinders the rotation of the FP 12 increases, so the rotation speed of the FP 12 decreases and the counter electromotive force generated in the motor of the FP 12 decreases. As a result, the drive current increases.

  When the energization of the metering valve 24 is turned on during the pumping stroke and the metering valve 24 is closed, the fuel inlet 26 is closed, so that the fuel in the pressurizing chamber 200 is pressurized as the plunger 22 moves up. When the metering valve 24 is closed, the fuel in the pressurizing chamber 200 is not returned to the low-pressure pipe 100, so that the low-pressure fuel pressure detected by the pressure sensor 32 rapidly decreases.

When the fuel pressure in the low-pressure system decreases, the rotation speed of the FP 12 increases and the back electromotive force generated in the motor of the FP 12 increases. As a result, the drive current decreases.
When the fuel pressure in the pressurizing chamber 200 becomes equal to or higher than the opening pressure of the discharge valve 28, the discharge valve 28 is opened, and the fuel in the pressurizing chamber 200 is pumped to the common rail 40 through the high-pressure pipe 104.

  The ECU 60 turns off the energization of the metering valve 24 before the plunger 22 reaches the top dead center of the pumping stroke when a predetermined time has elapsed after the energization of the metering valve 24 is turned on. In this case, the valve member of the metering valve 24 receives a force in the valve closing direction that closes the fuel inlet 26 due to the fuel pressure in the pressurizing chamber 200, so that the metering valve 24 maintains the closed state.

  When the plunger 22 reaches the top dead center in a state where the energization to the metering valve 24 is turned off, the pumping stroke is finished. When the plunger 22 starts to descend from the top dead center, the metering valve 24 that is turned off is opened and the suction stroke is started, so that fuel is sucked into the pressurizing chamber 200.

Next, an estimation method for estimating the pumping amount of the high-pressure pump 20 by detecting a change in the low-pressure fuel pressure or a physical quantity related to the low-pressure fuel pressure will be described.
(Pumping amount estimation)
The pumping amount of the high-pressure pump 20 is such that the plunger 22 reaches the top dead center after the metering valve 24 is closed and the pressurization of the fuel in the pressurizing chamber 200 is started and the discharge valve 28 is opened. Thus, it is determined by the pressurizing period until the pumping is completed.

  As described above, in the pumping stroke, when the plunger 22 starts to rise from the bottom dead center to the top dead center, the low-pressure fuel pressure rises, and when the metering valve 24 is closed and fuel pumping starts, the low pressure is started. The fuel pressure of the system drops rapidly. Accordingly, in the pumping stroke, when the period from when the low-pressure fuel pressure starts to rise to when it suddenly drops is the pressure rising period, the pressurizing period is from the pumping stroke period to the pressure rising period representing the pumping stroke period. Is a value obtained by subtracting.

  Judging from the crank angle that represents the rotation angle of the crankshaft that drives the camshaft, the pressure rise period varies depending on the valve closing timing of the metering valve 24, but the pumping stroke period is a fixed value regardless of the engine speed. is there. Therefore, if the pressure increase period is known, the pressurization period is determined, and the pumping amount of the high-pressure pump 20 can be estimated from the pressurization period. Since the pumping stroke period is a fixed value, the pumping amount of the high-pressure pump 20 can be estimated from the pressure rising period.

The pumping amount can be estimated as follows from (1) the detected pressure of the pressure sensor 32 or (2) the driving current of the FP 12.
(1) Pressure detected by the pressure sensor 32 When the pressure sensor 32 detects the low-pressure fuel pressure, the pressure increase period Tp from when the low-pressure fuel pressure starts to rise until the rise ends and rapidly decreases. Can be obtained directly. The rise start timing and the rise end timing of the low-pressure fuel pressure are detected by the time when the ECU 60 performs sampling, and the pressure rise period Tp is also obtained by time.

Specifically, the pumping amount Q of the high-pressure pump 20 is obtained from the following equation (1), where TG is the fuel pressure rising start timing and TR is the rising end timing.
Q = F (TG-TR) (1)
(TG-TR) is a parameter representing the pressure increase period Tp. As described above, if the pressure increase period is known, the pressurization period is determined. The function F is a mathematical expression or map data for obtaining a pumping amount determined by the cam profile using (TG-TR) as a parameter.

  However, since the pumping amount cannot be obtained with the pressure increase period Tp expressed in time, the pressure increase period Tp expressed in time is converted into a crank angle based on the engine speed, and expressed in angle. The pumping amount is obtained from the passed pressure increase period Tp.

  Here, if there is an error in the mounting angle of the high-pressure pump 20, the rising start timing TG and the rising end timing TR may be different from the crank angle when the high-pressure pump 20 is normally mounted. Further, the detected rise start timing TG and rise end timing TR may deviate from the actual rise start timing TG and rise end timing TR due to the propagation delay of the fuel pressure detected by the pressure sensor 32.

  However, the attachment of the high-pressure pump 20 is obtained by obtaining the pumping amount of the high-pressure pump 20 by using the difference (TG-TR) between the rising start timing TG and the rising end timing TR as a parameter representing the pressure rising period as in the equation (1). The pumping amount can be estimated with high accuracy by offsetting the angle error and the pressure propagation delay.

  If the error in the mounting angle of the high-pressure pump 20 and the propagation delay of the fuel pressure detected by the pressure sensor 32 are negligible, the period from the rising end timing TR to the top dead center of the pumping stroke is the pressurizing period. Therefore, the pumping amount of the high-pressure pump 20 may be estimated only from the rising end timing TR.

(2) Drive Current The drive current of the FP 12 changes according to the low-pressure fuel pressure as described above, although there is a time delay with respect to the low-pressure fuel pressure detected by the pressure sensor 32. The current increase period Ti, which is a period between the increase start timing TG at which the drive current starts increasing and the increase end timing TR at which the increase ends, is the same length as the pressure increase period Tp. Accordingly, by obtaining the current rise period Ti from the rise start timing and the rise end timing of the drive current, the high pressure pump 20 is pumped from the equation (1) in the same manner as when the pressure sensor 32 detects the low pressure fuel pressure. The quantity Q can be determined.

  Note that the change in the low-pressure fuel pressure caused by the operation of the high-pressure pump 20 attenuates due to the piping length while propagating from the high-pressure pump 20 to the FP 12. If this attenuation is large, it becomes difficult to obtain the current rising period Ti with high accuracy from the change in the driving current of the FP 12. Therefore, in order to reduce the attenuation of the fuel pressure propagating to the FP 12 as much as possible, it is desirable to use a material having a high elastic coefficient for the low-pressure pipe 100.

  Further, the value of the low-pressure fuel pressure detected by the pressure sensor 32 is the difference between the regulator valve 30, the rotation speed of the high-pressure pump 20, the injection amount of the fuel injection valve 50, and the foreign matter of the fuel filter installed in the low-pressure system. It varies depending on the degree of pressure loss due to collection, fuel properties, fuel temperature, and the like. Therefore, even if the fuel pressure value detected by the pressure sensor 32 is compared with a fixed threshold value, the fuel pressure rise start timing and rise end timing cannot be obtained with high accuracy.

  Therefore, the pressure rise period Tp can be obtained with high accuracy by obtaining the rise start timing and the rise end timing using a differential value, a slope, a change width, or the like of the low-pressure fuel pressure.

  Similarly, when obtaining the rise start timing and rise end timing of the drive current of the FP 12, by obtaining the rise start timing and the rise end timing with a differential value, slope, change width, etc. of the drive current, or a combination thereof, The current rising period Ti can be obtained with high accuracy.

  In the case of the driving current of the FP 12, noise is generated as shown in FIG. 3 due to pressure pulsation generated by blades formed on the outer periphery of the impeller when the FP 12 pumps fuel, and rotational speed unevenness caused by magnetic unevenness in the circumferential direction of the motor. Occurs. Therefore, it is desirable to obtain the rise start timing and rise end timing of the drive current after removing this noise by the band pass filter.

  Next, the pumping amount control processes 1 and 2 of the high-pressure pump 20 executed by the ECU 60 according to a control program stored in the ROM or the like will be described. In the flowcharts of FIGS. 4 and 5, “S” represents a step.

(Pressure feed amount control process 1)
In the pumping amount control process 1 shown in FIG. 4, the pumping amount of the high-pressure pump 20 is estimated based on the driving current of the FP 12.

  The ECU 60 samples the drive current of the FP 12 at a predetermined time interval and performs AD conversion (S400), and performs AD conversion in a noise frequency band determined by the number of rotations of the FP 12 and the number of impeller blades and the magnetic unevenness of the FP 12 motor. A band pass filter is applied to the converted value (S402).

  It is determined that the drive current rise start timing TG is reached when both the forward and backward inclination and the rise width of the drive current after passing through the filter are in a predetermined rise range (S404). When both the forward and backward inclination and the decrease range are within the predetermined decrease ranges, it is determined that the drive current increase end timing TR is reached (S406).

In S408, the ECU 60 calculates the estimated pumping amount of the high-pressure pump 20 from the equation (1) based on the rising start timing TG and the rising end timing TR.
In S410, the ECU 60 determines whether or not the pressure sensor 42 as the rail pressure sensor is normal. Whether the pressure sensor 42 is normal is determined based on the level of the output signal of the pressure sensor 42. If the output signal of the pressure sensor 42 changes within a predetermined output level range, the pressure sensor 42 is normal, and if the output level is fixed to “high” or “low”, it is determined that the pressure sensor 42 is abnormal. To do.

  If the pressure sensor 42 is normal (S410: Yes), for example, the target pumping amount is determined so that the common rail pressure detected by the pressure sensor 42 follows the target pressure determined from the engine operating state, and becomes the target pumping amount. The metering valve 24 is energized to control the pressurization start timing (S412).

  In this case, the metering valve 24 may be energized and controlled so that the target pumping amount is determined based on the differential pressure between the target pressure and the actual pressure without considering the actual pumping amount of the high-pressure pump 20. The energization to the metering valve 24 may be feedback controlled so that the estimated pumping amount obtained from the equation (1) becomes the target pumping amount determined based on the differential pressure between the target pressure and the actual pressure.

  If the pressure sensor 42 is abnormal (S410: No), the metering is performed based on the estimated pumping amount obtained from the equation (1) so that the pumping amount of the high-pressure pump 20 becomes the target pumping amount required from the engine operating state. The valve 24 is energized and controlled (S414). The energization control for the metering valve 24 at this time may be open control or feedback control.

(Pressure feed amount control process 2)
In the pumping amount control process 2 shown in FIG. 5, the pumping amount of the high-pressure pump 20 is estimated based on the low-pressure fuel pressure detected by the pressure sensor 32.

  The ECU 60 samples the output signal of the pressure sensor 32 that detects the low-pressure fuel pressure at predetermined time intervals and performs AD conversion (S420). Then, it is determined that it is the start timing TG of the low pressure fuel pressure when both the forward and backward inclination and the increase range of the low pressure fuel pressure are within a predetermined increase range (S422). It is determined that the low-pressure fuel pressure rise end timing TR is reached when both the fuel pressure gradient before and after and the reduction range are within the predetermined reduction ranges (S424). The processing after S426 is substantially the same as the processing after S408 in FIG.

  In the pumping amount control process 2 of FIG. 5, the pumping amount of the high-pressure pump 20 is estimated based on the low-pressure fuel pressure detected by the pressure sensor 32, so that the pumping amount of the high-pressure pump 20 can be controlled with higher accuracy.

  According to the present embodiment described above, since the pumping amount of the high-pressure pump 20 is estimated based on the driving current of the FP 12 that changes in relation to the fuel pressure of the low-pressure system or the fuel pressure itself of the low-pressure system, based on the estimated pumping amount. The pumping amount of the high-pressure pump 20 can be accurately adjusted to the target pumping amount.

  Further, even if there is no high pressure sensor for detecting the fuel pressure of the common rail 40, the pumping amount of the high pressure pump 20 can be adjusted with high accuracy. Even when the low-pressure fuel pressure is detected by the pressure sensor, a pressure sensor that is less expensive than the high-pressure fuel pressure sensor can be used.

When estimating the pumping amount of the high-pressure pump 20 based on the driving current of the FP 12, both the high-pressure and low-pressure pressure sensors may be unnecessary.
[Other Embodiments]
In the above embodiment, the driving current of the FP 12 is detected as a physical quantity related to the low-pressure fuel pressure. In addition to this, as long as the rotation speed of the FP 12 or the flow rate of the low-pressure pipe 100 can be detected, these may be detected as physical quantities related to the fuel pressure of the low-pressure system.

  In the above embodiment, the rise start timing and the rise end timing are detected based on both the drive current or the slope of the low-pressure fuel pressure and the change width represented by the rise or fall width. On the other hand, the rise start timing and the rise end timing may be detected based only on the gradient or change width of the drive current or the low-pressure fuel pressure. Further, a differential value may be used instead of the slope.

  In the above embodiment, the driving current of the FP 12 or the fuel pressure of the low pressure system is sampled at predetermined time intervals, and the rising start timing and the rising end timing are detected. On the other hand, the driving current of the FP 12 or the low-pressure fuel pressure may be sampled in synchronization with the crank angle to detect the rising start timing and the rising end timing.

  The present invention is not limited to a common rail system for a diesel engine, and may be applied to a fuel injection system of a direct injection gasoline engine that accumulates fuel in a pressure accumulating chamber formed by a delivery pipe.

  In the above embodiment, the functions of the detection value acquisition means, the control means, and the pumping amount estimation means are realized by the ECU 60 whose functions are specified by the control program. On the other hand, at least some of the functions of the plurality of means may be realized by hardware whose functions are specified by the circuit configuration itself.

  As described above, the present invention is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist thereof.

2: fuel injection system, 12: FP (low pressure pump), 20: high pressure pump, 24: metering valve, 32: pressure sensor, 40: common rail, 50: fuel injection valve, 60: ECU (fuel injection control device, detection) Value acquisition means, control means, pumping amount estimation means)

Claims (5)

The pressurization start timing for pressurizing the fuel supplied from the electric low-pressure pump (12) by the high-pressure pump (20) is controlled by the metering valve (24) to meter the pumping amount of the high-pressure pump, and the high-pressure pump A fuel injection control device (60) applied to a fuel injection system (2) for accumulating the fuel pressurized in the pressure accumulation chamber (40) and injecting the fuel from the fuel injection valve (50),
Detection value acquisition means (S400) that acquires, as an electrical signal, a detection value of either a low-pressure fuel pressure between the low-pressure pump and the high-pressure pump or a physical quantity related to the fuel pressure.
, S420),
Pumping amount estimating means (S408, S426) for estimating the pumping amount of the high-pressure pump based on the detection value acquired by the detection value acquiring means;
Control means (S414, S432) for adjusting the pressurization start timing by controlling the metering valve based on the pumping amount estimated by the pumping amount estimating means and metering the pumping amount of the high-pressure pump. ,
A fuel injection control device comprising: The fuel injection system includes a pressure accumulation chamber sensor (42) for detecting a fuel pressure in the pressure accumulation chamber,
The control means (S410, S412, S414, S428, S430, S432) controls the metering valve based on the fuel pressure of the pressure accumulation chamber detected by the pressure accumulation chamber sensor when the pressure accumulation chamber sensor is normal. , When the pressure accumulation chamber sensor becomes abnormal, the metering valve is controlled based on the pumping amount estimated by the pumping amount estimating means .
The fuel injection control device according to claim 1 . The fuel injection control device according to claim 1 or 2 , wherein the detection value acquisition means (S400) acquires a detection value of a driving current of the low-pressure pump as a detection value of the physical quantity. The fuel injection control device according to claim 1 or 2 , wherein the detection value acquisition means (S420) acquires a detection value of the fuel pressure of the low pressure system from a pressure sensor installed in the low pressure system. . An electric low-pressure pump;
A high-pressure pump that controls the pressurization start timing for pressurizing the fuel supplied from the low-pressure pump with a metering valve to meter the pumping amount;
A common rail for accumulating fuel supplied from the high-pressure pump;
A fuel injection valve for injecting fuel accumulated in the common rail;
A fuel injection control device according to any one of claims 1 to 4 ,
A fuel injection system comprising:

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