JP4957749B2 - Fuel injection control device - Google Patents

Description

  The present invention relates to a fuel injection control device applied to an internal combustion engine for vehicle travel.

  Conventionally, this type of fuel injection control device is described in Patent Document 1. In this prior art, the amount of fuel discharged from the fuel pump is adjusted by adjusting the amount of fuel sucked into the fuel pump by means of a suction metering valve, and consequently the fuel pressure in the common rail (hereinafter referred to as rail pressure) is controlled to the target pressure. It has come to be.

  Specifically, the intake metering valve includes a housing in which a fuel flow path through which fuel sucked into the fuel pump flows, and a housing that is slidably displaceable in the housing. A spool that adjusts the spool in one direction by an elastic force, and a solenoid that attracts the spool by a magnetic force in a direction opposite to the one direction. The fuel suction amount of the fuel pump is adjusted by adjusting the opening area of the flow path.

  In the intake metering valve having such a configuration, when wear of the inner peripheral surface of the housing and the outer peripheral surface of the spool progresses due to the secular change of the intake metering valve, the wear dust is applied to the inner peripheral surface of the housing and the outer peripheral surface of the spool. Occurs. For this reason, when wear progresses, resistance (hereinafter referred to as sliding resistance) received by the spool when the spool is displaced on the inner peripheral surface of the housing increases.

  When the sliding resistance increases, the displacement position of the spool cannot be adjusted properly. In other words, the displacement of the spool becomes awkward. As a result, the intake fuel amount of the fuel pump cannot be adjusted properly by the intake metering valve, and the actual pressure cannot be controlled appropriately. Specifically, the actual rail pressure (hereinafter referred to as actual pressure) deviates significantly from the target pressure.

  In view of this point, in this prior art, when it is determined that the displacement of the spool is reduced, the amount of energization to the solenoid is corrected and the spool is forced to vibrate so that the displacement of the spool is recovered normally. Yes.

  More specifically, when the time during which the difference between the actual pressure and the target pressure is greater than a predetermined value continues for a predetermined time, it is determined that the spool has become less irritating and the spool is forcibly vibrated.

JP 2008-75452 A

  However, in the above-described prior art, since it is determined that the displacement of the spool has been reduced, the spool is forcibly oscillated to recover the spool displacement normally, so that a delay in following the actual pressure with respect to the target pressure occurs to some extent.

  That is, the spool is forcibly vibrated to recover the spool displacement normally after the time during which the difference between the actual pressure and the target pressure is greater than the predetermined value continues for a predetermined time, so that the actual pressure in the common rail becomes the target pressure. On the other hand, the time to shift significantly becomes longer.

  Such pressure follow-up delay becomes a problem particularly when the vehicle is accelerated again after the vehicle is decelerated (hereinafter referred to as reacceleration). The reason for this will be described below.

  Since the fuel injection amount may be very small at the time of deceleration, the fuel discharge amount of the fuel pump becomes very small. On the other hand, since a large amount of fuel injection is required at the time of acceleration, the fuel discharge amount of the fuel pump increases. For this reason, the increase change amount of the fuel discharge amount of the fuel pump becomes large at the time of reacceleration.

  When a pressure follow-up delay occurs during such re-acceleration, the actual pressure in the common rail is greatly reduced with respect to the target pressure, and in the worst case, engine stall may occur.

  An object of this invention is to suppress the pressure follow-up delay at the time of reacceleration in view of the said point.

In order to achieve the above object, in the invention according to claim 1, a high-pressure pump (31) that pressurizes and discharges fuel;
A common rail (13) for storing high-pressure fuel discharged from the high-pressure pump (31);
An intake metering valve (32) for adjusting the intake fuel amount of the high-pressure pump (31);
A fuel injection valve (15) for injecting high-pressure fuel supplied from the common rail (13) into the internal combustion engine;
A control device (20) for controlling the intake metering valve (32) so that the fuel pressure in the common rail (13) becomes a target pressure,
The intake metering valve (32)
A cylinder (322) in which a flow path (327) through which fuel sucked into the high-pressure pump (31) flows is formed;
A spool (323) accommodated in the cylinder (322) so as to be slidably displaceable and adjusting a flow passage area of the flow passage (327) according to a displacement position;
A spring (324) for pressing the spool (323) in one direction by an elastic force;
A solenoid (321) for sucking the spool (323) in a direction opposite to the one direction when energized by the control device (20);
The control device (20) is characterized in that when the vehicle decelerates, the spool (323) is forcibly vibrated by correcting the energization amount to the solenoid (321).

  According to this, the spool (323) is forcibly vibrated when the vehicle is decelerated regardless of whether the displacement of the spool (323) is astringent or not. As compared with the case where the spool is forcedly vibrated after that, the pressure follow-up delay at the time of reacceleration can be suppressed.

Further, in the invention according to claim 1, the control device (20) has a spool determination means for determining whether the displacement of (323) is normal (S130), the displacement of the spool (323) When the determination means (S130) determines that the current is normal, the correction of the energization amount is stopped.

  According to this, since the forced vibration of the spool (323) is stopped when the displacement of the spool (323) is normal, the forced vibration of the spool (323) is performed more than necessary, which adversely affects the pressure behavior. Can be prevented.

Furthermore, in the invention according to claim 1, comprising a co Monreru (13) detecting means for the fuel pressure to the periodically detected (16), determination means (S130), the detection means at the time of re-acceleration of the vehicle (16 ), The displacement of the spool (323) is determined to be normal when the fuel pressure detected by (1) rises.

  Accordingly, it is possible to appropriately determine whether or not the displacement of the spool (323) is normal. Incidentally, “at the time of reacceleration” in the present invention means a time when the vehicle is accelerated again after the vehicle is decelerated.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

1 is an overall configuration diagram of a fuel injection control device according to an embodiment of the present invention. It is sectional drawing of the fuel pump of FIG. FIG. 3 is a cross-sectional view of the intake metering valve of FIG. 2. It is a wave form diagram explaining the electricity supply control with respect to the solenoid of FIG. It is a flowchart which shows the procedure which determines the start and stop of DUTY assist control. It is a flowchart which shows the procedure which calculates the DUTY ratio of a solenoid drive signal. It is a time chart which shows an example of the control result by one Embodiment. It is a wave form diagram explaining a basic DUTY ratio, a DUTY assist amount, and a drive DUTY ratio.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an overall configuration diagram of a fuel injection control device according to the present embodiment. The fuel injection control device controls fuel injection to an internal combustion engine (engine) (not shown), and constitutes a common rail diesel engine in this embodiment.

  The fuel in the fuel tank 10 is pumped up by the fuel pump 12 through the fuel filter 11 and pressurized (suppressed) to the common rail 13. The common rail 13 stores the fuel pumped from the fuel pump 12 in a high pressure state, and supplies the fuel to the fuel injection valve 15 via the high pressure fuel passage 14.

  The fuel injection valve 15 injects fuel into each cylinder of an internal combustion engine (not shown). An internal combustion engine (not shown) burns fuel in each cylinder to generate driving force for running the vehicle. The fuel injection valve 15 is provided in each cylinder according to the number of cylinders (in this example, 4 cylinders) of an internal combustion engine (not shown). On the other hand, the common rail 13 is provided in common to each cylinder of an internal combustion engine (not shown).

  The fuel pressure in the common rail 13 (hereinafter referred to as rail pressure) is periodically detected by the rail pressure sensor 16. In other words, the rail pressure sensor 16 constitutes detection means for periodically detecting the rail pressure.

  The operating state of the internal combustion engine is detected by various sensors such as a crank angle sensor 17 and an accelerator sensor 18. The crank angle sensor 17 detects the rotation angle of the crankshaft 19 of the internal combustion engine. The accelerator sensor 18 detects an operation amount of an accelerator pedal (not shown).

  The control device (ECU) 20 is mainly composed of a microcomputer, and controls the output of the diesel engine based on the detection results of the various sensors. For example, the ECU 20 controls the fuel pump 12 to feedback control the rail pressure detected by the rail pressure sensor 16 to the target value.

  FIG. 2 is a cross-sectional view of the fuel pump 12 of FIG. The fuel pump 12 includes a feed pump 30 that pumps up the fuel in the fuel tank 10, a high-pressure pump 31 that pressurizes and discharges the fuel pumped up by the feed pump 30, and a suction metering that adjusts the amount of fuel sucked in the high-pressure pump 31. And a valve (SCV) 32.

  The feed pump 30 functions as a low-pressure supply pump that sucks the fuel in the fuel tank 10 from the inlet 301 and sends the fuel to the high-pressure pump 31. In this example, a trochoid pump driven by the rotation of the drive shaft 33 is used as the feed pump 30. The drive shaft 33 is connected to the crankshaft 19 of the internal combustion engine, and is driven to rotate as the crankshaft 19 rotates.

  The regulator valve 302 limits the discharge pressure of the feed pump 30 to a predetermined pressure or less. Specifically, the regulator valve 302 causes the discharge side and the supply side of the feed pump 30 to communicate with each other when the discharge pressure of the feed pump 30 exceeds a predetermined pressure.

  The fuel pumped up by the feed pump 30 is sucked into the high-pressure pump 31 through the fuel passage 303. The SCV 32 adjusts the amount of fuel drawn into the high-pressure pump 31 by adjusting the amount of fuel flowing through the fuel passage 303.

  The high-pressure pump 31 is a plunger pump that pressurizes the fuel metered by the SCV 32 and discharges the fuel to the outside (common rail 13 in this example). The high-pressure pump 31 includes a plunger 311 that is reciprocally driven by a drive shaft 33, a pressure chamber 312 whose volume is changed by the reciprocation of the plunger 311, and a suction valve that communicates and blocks the pressure chamber 312 and the feed pump 30 side. 313, and a discharge valve 314 for communicating and blocking the pressurizing chamber 312 and the common rail 13 side.

  The plunger 311 is pressed against a cam ring 315 mounted around the eccentric cam 331 of the drive shaft 33 by a spring 316. When the drive shaft 33 rotates, the plunger 311 is pumped to the top dead center and the pressure feed along with the eccentric operation of the cam ring 315. Reciprocates between bottom dead center.

  When the pressure in the pressurizing chamber 312 decreases due to the lowering of the plunger 311, the discharge valve 314 is closed and the suction valve 313 is opened. As a result, fuel is supplied from the feed pump 30 into the pressurizing chamber 312 via the SCV 32.

  On the contrary, when the pressure in the pressurizing chamber 312 rises due to the rise of the plunger 311, the suction valve 313 is closed. When the pressure in the pressurizing chamber 312 reaches a predetermined pressure, the discharge valve 314 is opened, and the high-pressure fuel pressurized in the pressurizing chamber 312 is supplied toward the common rail 13.

  FIG. 3 is a cross-sectional view of the SCV 32 of FIG. In the example of FIG. 2, a normally closed type that is fully closed when the solenoid 321 is not energized is used as the SCV 32. That is, the SCV 32 increases the flow path area when the fuel flows from the feed pump 30 to the high-pressure pump 31 when the drive current to the solenoid 321 is increased.

  The SCV 32 has a cylinder 322 formed in a cylindrical shape as a whole. A spool 323 that is slidable in the axial direction is accommodated in the cylinder 322. The spool 323 has a cylindrical outer shape parallel to the axial direction of the cylinder 322. The spool 323 is pressed in one axial direction (left direction in FIG. 3) by the elastic force of the spring 324.

  A fuel introduction path 325 extending in the axial direction is formed in the spool 323, and a plurality of communication paths 326 extending in the radial direction are formed. On the other hand, a plurality of flow paths 327 extending in the radial direction are formed in the cylinder 322. The overlapping area between the communication path 326 of the spool 323 and the flow path 327 of the cylinder 322 is adjusted by the displacement position of the spool 323.

  One end portion (left end portion in FIG. 3) of the fuel introduction path 325 constitutes an inlet for low-pressure fuel pumped up by the feed pump 30. The communication path 326 of the spool 323 and the flow path 327 of the cylinder 322 constitute a flow path in which the low-pressure fuel introduced into the fuel introduction path 325 flows to the high-pressure pump 31.

  A housing 328 is assembled to the cylinder 322, and a solenoid 321 is accommodated in an annular space formed between the cylinder 322 and the housing 328. The solenoid 321 is energized by the ECU 20 via the connector 329.

  When the solenoid 321 is energized, the spool 323 is attracted to the inside of the solenoid 321 by the magnetic field generated in the solenoid 321. For this reason, the spool 323 is displaced in the direction opposite to the one direction (the right direction in FIG. 3) against the elastic force of the spring 324, and the overlapping area of the communication path 326 and the flow path 327 (the flow of the flow path 327). Road area) increases. In other words, the opening degree of the SCV 32 increases.

  The opening degree of the SCV 32 is adjusted according to the target current value for the solenoid 321, and the opening degree increases as the target current value increases. Incidentally, FIG. 3 shows a valve open state of the SCV 32 in which the flow path 327 of the cylinder 322 and the communication path 326 of the spool 323 communicate with each other. In this state, the low-pressure fuel introduced from the inlet of the fuel introduction path 325 is supplied to the high-pressure pump 31 via the communication path 326 and the flow path 327.

  FIG. 4 is a waveform diagram for explaining energization control for the solenoid 321. In the present embodiment, energization of the solenoid 321 is performed by inputting a drive signal having a predetermined frequency, and the average value (average current) of the current flowing through the solenoid 321 is set to the target current based on the duty ratio (DUTY ratio) of the drive signal. Adjusted to the value.

  Next, DUTY assist control, which is a main part of fuel injection control with the above configuration, will be described. The DUTY assist control is control that is performed to recover normally the displacement of the spool 323 that has become astringent due to the secular change of the SCV 32. Specifically, the spool 32 is forcibly vibrated.

  5 and 6 are flowcharts showing the processing procedure of the DUTY assist control. This process is repeatedly executed by the ECU 20 at the same cycle as the fuel discharge cycle from the fuel pump 12, for example. FIG. 7 is a time chart illustrating an example of a control result according to the flowcharts of FIGS. 5 and 6.

  First, the start and stop of the DUTY assist control are determined according to the flowchart of FIG. In the flowchart of FIG. 5, first, in step S100, it is determined whether or not the DUTY assist execution flag has already been turned on (ON). The DUTY assist execution flag is turned on when the DUTY assist control is performed, and is turned off (OFF) when the DUTY assist control is stopped.

  If the DUTY assist execution flag is off, the process proceeds to step S110. Step S110 determines whether or not the vehicle is decelerating. In this example, it is determined that the vehicle is decelerating when the condition shown in FIG. 5 is satisfied.

  If it is determined that the vehicle is not decelerating, the processing of the flowchart of FIG. 5 is temporarily ended without changing the DUTY assist execution flag, that is, while the DUTY assist execution flag remains off.

  If it is determined in step S110 that the vehicle is decelerating, the process proceeds to step S120, and after the DUTY assist execution flag is turned on, the process of the flowchart of FIG. 5 is temporarily ended.

  Here, an example of the determination condition in step S110 will be described. In step S <b> 110 of FIG. 5, the command injection amount is a command value of the injection amount for the fuel injection valve 15. The actual pressure change amount is a change amount of an actual rail pressure (hereinafter referred to as an actual pressure) periodically detected by the rail pressure sensor 16, and more specifically, an actual pressure change detected most recently. It is the difference between the pressure and the actual pressure detected last time. The pressure deviation is a difference between a rail pressure target value (hereinafter referred to as a target pressure) and an actual pressure.

  The command injection amount is calculated in accordance with, for example, an accelerator pedal operation amount detected by the accelerator sensor 18, and the target pressure is calculated based on, for example, the command injection amount and the rotation speed of the crankshaft 19. The rotation speed of the crankshaft 19 can be calculated based on the rotation angle of the crankshaft 19 detected by the crank angle sensor 17.

  In the example of FIG. 5, in step S110, it is determined that the vehicle is decelerating when the command injection amount is equal to or less than a predetermined threshold, the actual pressure change amount is less than the predetermined threshold, and the pressure deviation is equal to or less than the predetermined threshold.

  That is, since the amount of depression of the accelerator pedal is reduced during deceleration, the command injection amount is reduced. Moreover, since the target pressure is reduced during deceleration, the actual pressure change amount is reduced. In the example of FIG. 7, the actual pressure change amount P2-P1 during deceleration is a negative value.

  Moreover, since the target pressure is reduced during deceleration, the pressure deviation is reduced. In the example of FIG. 7, the pressure deviation Pt2-P2 during deceleration is a negative value. From the above, in this example, it is determined that the vehicle is decelerating when the above condition is satisfied in step S110.

  On the other hand, if the DUTY assist execution flag is on in step S100, the process proceeds to step S130. Step S130 constitutes determination means for determining whether or not the displacement of the spool 323 is normal.

  In this embodiment, step S130 determines whether the vehicle is reaccelerated (when accelerating again after deceleration) and whether the displacement of the spool 323 is normal. In this example, it is determined that the vehicle is reaccelerated when the condition shown in FIG. 5 is satisfied, and that the displacement of the spool 323 is normal.

  If it is not during re-acceleration or if it is determined that the displacement of the spool 323 is not normal, the processing of the flowchart of FIG. 5 is temporarily terminated without changing the DUTY assist execution flag, that is, while the DUTY assist execution flag remains on. To do.

  If it is determined that the reacceleration is in progress and the displacement of the spool 323 is normal, the process proceeds to step S140, and after the DUTY assist execution flag is turned off, the process of the flowchart of FIG.

  Here, an example of the determination condition in step S130 will be described. In the example of FIG. 5, in step S130, when the actual pressure change amount is larger than a predetermined threshold value and the pressure deviation is equal to or larger than the predetermined threshold value, it is determined that reacceleration is occurring and the displacement of the spool 323 is normal. .

  That is, the target pressure is increased during re-acceleration. When the displacement of the spool 323 is normal, when the target pressure is increased, the actual pressure follows the target pressure and the actual pressure change amount increases.

  This will be specifically described with reference to FIG. In FIG. 7D, the thick solid line shows the change in actual pressure in the present embodiment, and the thin solid line shows the change in actual pressure in the comparative example. In the comparative example, DUTY assist control is not performed during deceleration. In other words, the comparative example shows an example in which the displacement of the spool 323 becomes less steep during re-acceleration.

  In the comparative example, the displacement of the spool 323 is not normal at the time of re-acceleration and is astringent. Therefore, the increase in the actual pressure is slow even if the target pressure is increased. In other words, the followability of the actual pressure with respect to the target pressure is not good.

  On the other hand, in the present embodiment, since the DUTY assist control is performed at the time of deceleration, the displacement of the spool 323 is normally recovered by the DUTY assist control even if the displacement of the spool 323 becomes awkward at the time of deceleration.

  Therefore, in the present embodiment, if the target pressure is increased during reacceleration, the actual pressure increases following the target pressure, so the actual pressure change amount is larger than in the comparative example in which the displacement of the spool 323 is not normal. is there. Incidentally, in the example of FIG. 7, the actual pressure change amount P <b> 4-P <b> 3 is a positive value at the time of reacceleration and when the displacement of the spool 323 is normal.

  Further, at the time of reacceleration, since the target pressure is increased, the pressure deviation is increased. In the example of FIG. 7, the pressure deviation Pt4-P4 at the time of reacceleration has a positive value. From the above, in this example, when the above condition is satisfied, it is determined that reacceleration is performed and that the displacement of the spool 323 is normal.

  Next, the DUTY ratio of the drive signal input to the solenoid 321 is calculated according to the flowchart of FIG. In the flowchart of FIG. 6, first, the basic DUTY ratio is calculated in step S200.

  This basic DUTY ratio is a provisionally determined value of the DUTY ratio of the drive signal input to the solenoid 321. On the other hand, the drive DUTY ratio calculated in steps S220 and S240 described later is a final determination value of the DUTY ratio of the drive signal input to the solenoid 321.

  An example of a method for calculating the basic DUTY ratio will be described. First, a target current value (average current value) for the solenoid 321 for feedback control of the actual pressure to the target pressure is calculated. Here, it is desirable to calculate the target current value including a proportional term and an integral term based on the difference between the actual pressure and the target pressure. At this time, for example, a feedforward term based on a command injection amount, a change mode of the target pressure, or the like may be added.

  Then, the target current value is converted into a DUTY ratio. The DUTY ratio is obtained by dividing the pulse width of the drive signal input to the solenoid 321 by the pulse period. The DUTY ratio calculated in this way is set as a basic DUTY ratio.

  In a succeeding step S210, it is determined whether or not the DUTY assist execution flag is turned on. When the DUTY assist execution flag is not turned on, the process proceeds to step S220, and the basic DUTY ratio is used as it is (without correction) as the drive DUTY ratio (drive DUTY ratio = basic DUTY ratio). And the process of the flowchart of FIG. 6 is once complete | finished.

  If the DUTY assist execution flag is on, the process proceeds to steps S230 and S240, and the DUTY ratio corrected (added or subtracted) from the basic DUTY ratio is set as the drive DUTY ratio. Here, the correction amount of the DUTY ratio with respect to the basic DUTY ratio is referred to as a DUTY assist amount (drive DUTY ratio = basic DUTY ratio + DUTY assist amount).

  FIG. 8 is a waveform diagram for explaining the basic DUTY ratio, the DUTY assist amount, and the drive DUTY ratio. In FIG. 8, the basic DUTY ratio = τ1 / T, the DUTY assist amount = τ2 / T, and the drive DUTY ratio = τ3 / T = (τ1 + τ2) / T. Incidentally, FIG. 8 shows an example in which the basic DUTY ratio is increased and corrected. In this case, the DUTY assist amount becomes a positive value. However, when the basic DUTY ratio is decreased and corrected, the DUTY assist amount is negative. Value.

  In step S230, a DUTY assist amount is calculated. In this example, DUTY assist is performed only for a certain period of time (180 ° CA in this example), so the DUTY assist amount is calculated according to the rotational speed of the crankshaft 19. Incidentally, “CA” of 180 ° CA is an abbreviation of crank angle.

  In this example, the DUTY assist amount is calculated according to the target valve lift change amount of the SCV 32. Specifically, the target valve lift change amount is replaced with the target current value change amount, and the DUTY assist amount is calculated according to the target current value change amount.

  In step S240, a drive DUTY ratio is calculated based on the basic DUTY and the DUTY assist amount (drive DUTY ratio = basic DUTY ratio + DUTY assist amount). And the process of the flowchart of FIG. 6 is once complete | finished.

  A thick solid line in FIG. 7C indicates the valve lift amount of the SCV 32 in the present embodiment. Incidentally, the thin solid line in FIG. 7C indicates the valve lift amount of the SCV 32 in the above-described comparative example, that is, in which the DUTY assist control is not performed during deceleration.

  As can be seen from FIG. 7C, in the present embodiment, the duty lift assist control is performed at the time of deceleration, so the valve lift amount of the SCV 32 varies greatly compared to the comparative example in which the duty free control is not performed.

  In the example of FIG. 7C, the valve lift amount of the SCV 32 is increased by DUTY assist control. Here, in this example, a normally closed type is used as the SCV 32. Therefore, in the example of FIG. 7C, the valve lift amount of the SCV 32 is increased by increasing the basic DUTY ratio by setting the DUTY assist amount to a positive value.

  Thus, in the present embodiment, the valve lift amount of the SCV 32 is forcibly changed by the DUTY assist control. In other words, by correcting the DUTY ratio of the drive signal input to the solenoid 321, the energization amount to the solenoid 321 is corrected and the spool 323 is forcibly vibrated. For this reason, similarly to the prior art of the above-mentioned Patent Document 1, even if the displacement of the spool 323 becomes awkward, the displacement of the spool 323 can be recovered normally.

  Here, in the prior art disclosed in Patent Document 1, the spool is forcibly vibrated after it is determined that the time during which the difference between the actual pressure and the target pressure is greater than a predetermined value has continued for a predetermined time and the displacement of the spool has been reduced. On the other hand, in this embodiment, regardless of whether or not the displacement of the spool 323 is moderate, DUTY assist control is performed during deceleration to forcibly vibrate the spool 323.

  For this reason, compared with the prior art of the said patent document 1, in this embodiment, since the displacement of the spool 323 can be recovered normally early, the pressure follow-up delay at the time of reacceleration can be suppressed.

  On the other hand, in the present embodiment, the DUTY assist control is performed at the time of deceleration regardless of whether the displacement of the spool 323 is moderate or not, so the DUTY assist control is performed at the time of deceleration even if the displacement of the spool 323 is normal. Will be. For this reason, if the duration of the DUTY assist control is long, the pressure behavior may be disturbed by the influence of the DUTY assist control when the displacement of the spool 323 is normal.

  In view of this point, in this example, since DUTY assist is performed only for a certain period of time (180 ° CA in this example), the effect of DUTY assist control on pressure behavior when the displacement of the spool 323 is normal. Can be suppressed.

  Further, in the present embodiment, the DUTY assist control is stopped when it is determined that the acceleration is re-accelerated and the displacement of the spool 323 is normal, so that the DUTY assist control is performed more than necessary, and the pressure behavior is adversely affected. It can prevent giving.

(Other embodiments)
In the above-described embodiment, a normally closed type that is fully closed when the solenoid 321 is not energized is used as the SCV 32. However, the SCV 32 is normally open that is fully opened when the solenoid 321 is not energized. A formula may be used.

  In the above embodiment, the energization amount for the solenoid 321 is adjusted by the DUTY ratio of the drive signal input to the solenoid 321. However, the present invention is not limited to this, and the method for adjusting the energization amount for the solenoid 321 is not limited thereto. Various known methods can be employed.

  In the above embodiment, the spool 323 is forcibly oscillated by correcting the increase in the energization amount for the solenoid 321. However, the spool 323 may be forcibly oscillated by correcting the decrease in the energization amount for the solenoid 321.

  In addition, the above-described embodiment is merely an example of a determination method at the time of deceleration of the vehicle, and the present invention is not limited to this, and various known methods are adopted as a determination method at the time of deceleration of the vehicle. Can do. For example, it may be determined when the vehicle is decelerating by detecting the traveling speed of the vehicle.

  In the above embodiment, the forced vibration of the spool 323 is stopped when it is determined that the displacement of the spool 323 is normal at the time of reacceleration. If it is determined that the displacement of 323 is normal, the forced vibration of the spool 323 may be stopped. In this case, for example, it may be determined that the displacement of the spool 323 is normal when a time during which the pressure deviation is equal to or less than a predetermined threshold continues for a predetermined time.

  In the above embodiment, the rail pressure is directly detected by the rail pressure sensor 16, but the rail pressure is indirectly detected by another sensor (for example, a sensor for detecting the fuel pressure in the fuel injection valve 15). Also good.

13 common rail 15 fuel injection valve 20 ECU (control device)
31 High pressure pump 32 SCV (Suction metering valve)
321 Solenoid 322 Cylinder 323 Spool 324 Spring 327 Flow path

Claims (1)

A fuel injection control device applied to an internal combustion engine that generates driving force for traveling of a vehicle,
A high-pressure pump (31) for pressurizing and discharging fuel;
A common rail (13) for storing high-pressure fuel discharged from the high-pressure pump (31);
An intake metering valve (32) for adjusting the intake fuel amount of the high-pressure pump (31);
A fuel injection valve (15) for injecting high-pressure fuel supplied from the common rail (13) into the internal combustion engine;
A control device (20) for controlling the suction metering valve (32) so that the fuel pressure in the common rail (13) becomes a target pressure,
The suction metering valve (32)
A cylinder (322) in which a flow path (327) through which fuel sucked into the high-pressure pump (31) flows is formed;
A spool (323) accommodated in the cylinder (322) so as to be slidably displaceable, and adjusting a flow area of the flow path (327) according to a displacement position;
A spring (324) for pressing the spool (323) in one direction by an elastic force;
A solenoid (321) for sucking the spool (323) in a direction opposite to the one direction when energized by the control device (20);
The control device (20) forcibly vibrates the spool (323) by correcting the energization amount to the solenoid (321) when the vehicle is decelerated , and the control device (20) further controls the spool (323). And determining means (S130) for determining whether or not the displacement is normal, and correcting the energization amount when the determining means (S130) determines that the displacement of the spool (323) is normal. A fuel injection control device that stops;
A detection means (16) for periodically detecting the fuel pressure in the common rail (13);
The determination means (S130) determines that the displacement of the spool (323) is normal when the fuel pressure detected by the detection means (16) rises during re-acceleration of the vehicle. A fuel injection control device.

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