JP2020067031A - Fuel injection control device - Google Patents

Abstract

To provide a fuel injection control device which can lower the internal pressure of a common rail without imposing thermal stress to a charging part as much as possible.SOLUTION: When lowering the internal pressure of a common rail at normal injection control or abnormal injection control, a first control IC close-controls a first valve, and a second control IC open-controls a second valve by carrying a pickup current Ipa 2 after carrying a peak current Ip2 to a second solenoid of at least one objective fuel injection device out of the fuel injection devices. Then, when lowering the internal pressure of the common rail at the normal injection control or the abnormal injection control, the second control IC sets a peak current Ip2/2 carried to the second solenoid of the objective fuel injection device lower than that at the normal injection control, and elongates a time for carrying the pickup current Ipa2 by a prescribed time Ta.SELECTED DRAWING: Figure 12

Description

  The present invention relates to a fuel injection control device.

  Conventionally, the applicant has proposed a fuel injection device that injects fuel from the tip of a nozzle by controlling hydraulic pressure using two solenoid valves (see, for example, Patent Document 1). The injector described in Patent Document 1 is configured such that fuel can be injected from a nozzle at the tip end by using an actuator using a piezo stack.

German Patent Application Publication No. 1020131122751

  When the fuel injection control device controls the fuel injection, the fuel is injected and controlled from the common rail accumulating the fuel to the internal combustion engine by using the plurality of fuel injection devices. When the fuel injection control device hydraulically controls fuel injection by using two solenoid valves (hereinafter, referred to as a first valve and a second valve, respectively) in a fuel injection device (also referred to as an injector) The first valve is driven to control the fuel injection timing, and the second valve is driven to control the fuel injection rate. The fuel injection rate can be changed by adjusting the opening speed of the nozzle needle at the tip of the fuel injection device.

  Further, when there is a pressure reduction request during the normal control, the fuel injection control device can reduce the internal pressure of the common rail by opening the second valve of the fuel injection device. Further, even if the high-pressure fuel pump that supplies high-pressure fuel to the fuel injection device is stuck on the pumping side, the second valve can be opened to reduce the hydraulic pressure in the hydraulic control chamber and prevent a high-pressure abnormality. As a result, the fuel pressure can be adjusted to the target pressure even during the normal control even when the high-pressure pump has a sticking failure on the pumping side.

  For example, when the internal combustion engine has four cylinders, four fuel injection devices are provided in the internal combustion engine. When the above-described two-valve configuration is adopted, two valves are provided for each of these four fuel injection devices, so the fuel injection control device controls eight valves.

  As described above, when there is a pressure reduction request during normal times or abnormal times, the second valves for all cylinders are opened simultaneously. However, if the fuel injection control device controls the opening of the second valves for all the cylinders at the same time, the energy supply load for the drive is large and the thermal stress is large, which may cause a malfunction. This can be solved by increasing the stored energy so that the valves for all cylinders can be controlled to be opened at the same time, but it is necessary to increase the capacitance value of the charging capacitor as the charging unit for storing energy. In this case, This is not preferable because the circuit size increases and the cost increases.

  An object of the present invention is to provide a fuel injection control device capable of reducing the internal pressure of the common rail without applying heat stress to the charging section as much as possible.

  The invention according to claim 1 is a fuel injection control device for controlling the injection of each fuel from a common rail (5) in which fuel is accumulated to an internal combustion engine (11) using a plurality of fuel injection devices (7 to 10). Intended. Each of the plurality of fuel injection devices includes a first solenoid (31), a first valve (29), a second solenoid (32), and a second valve (30). The first control section (52) controls the fuel injection timing by driving the first valve by energizing the first solenoid during normal injection control. During normal injection control, the second control unit (53) uses the charging voltage (Vboost2) charged in the charging unit (75) to supply the peak current (Ip2) indicating the maximum set value current to the second solenoid. Then, the second valve is driven to control the fuel injection rate by supplying a predetermined constant current (Ipb2) lower than the peak current without using the charging voltage.

  When the internal pressure of the common rail is reduced during normal injection control or during an abnormality, the first control unit controls the first valve to close and the second control unit controls the target fuel of at least one of the plurality of fuel injection devices. It is configured to control the opening of the second valve by energizing the second solenoid in the injection device.

  Then, when the internal pressure of the common rail is reduced during normal injection control or during an abnormality, the second control unit sets the peak current supplied to the second solenoid of the target fuel injection device lower than during normal injection control. At the same time, the control for extending the time for supplying the pickup current by a predetermined time is executed. According to the first aspect of the present invention, the peak current is set lower than that during normal injection control, so that the internal pressure of the common rail can be reduced without applying thermal stress to the charging section as much as possible.

  A fifth aspect of the present invention is directed to a fuel injection control device that controls injection of each of the fuels from a common rail in which fuel is accumulated to an internal combustion engine using a plurality of fuel injection devices. Each of the plurality of fuel injection devices includes a first solenoid (31), a first valve (29), a second solenoid (32), and a second valve (30). During normal injection control, the first controller (52) applies a current to the first solenoid to drive the first valve (29) and control fuel injection timing. During normal injection control, the second control unit (53) energizes the plurality of second solenoids using the charging voltage (Vboost2) charged in the same charging unit (75) to inject a plurality of fuels. The second valve (30) of the device (8, 9) is driven to change and control the fuel injection rate.

  When the internal pressure of the common rail is reduced during normal injection control or during an abnormality, the first control unit controls the first valve to close and the second control unit controls the target fuel of at least one of the plurality of fuel injection devices. It is configured to control the opening of the second valve by energizing the second solenoid in the injection device.

  Then, the second control unit sets the energization period of the second solenoid in the target fuel injection device to the energization period of the second solenoid during normal injection control in another fuel injection device in the period in which the internal pressure of the common rail is reduced. And have a different period. According to the fifth aspect of the present invention, the energization period of the second solenoid in the target fuel injection device is different from the energization period of the second solenoid during normal injection control in another fuel injection device. Even if a plurality of second solenoids are energized by using the same charging voltage of the charging unit, the current load applied to the charging unit can be dispersed and the thermal stress can be reduced. As a result, the internal pressure of the common rail can be reduced without applying heat stress to the charging section as much as possible.

Configuration diagram of a fuel injection control system in the first embodiment Sectional drawing which shows a fuel-injection apparatus typically. Explanatory drawing explaining the flow of fuel when lowering the internal pressure of the common rail Block diagram showing electrical configuration Circuit diagram of booster circuit Circuit diagram of valve drive Circuit diagram of pump driver Part 1 of the explanatory diagram for explaining the flow of injection control The figure which shows the change of the valve drive current supplied to the 1st and 2nd solenoid. Flowchart showing the processing when the internal pressure of the common rail is controlled to decrease Part 2 of the explanatory diagram for explaining the flow of injection control The figure which shows the change of the valve drive current at the time of normal and abnormalities in contrast. Part 3 of the explanatory diagram illustrating the flow of injection control Explanatory drawing explaining the flow of injection control in 2nd Embodiment. Flowchart showing the processing when the internal pressure of the common rail is controlled to decrease The figure which shows the change of the valve drive current at the time of normal and abnormalities in contrast.

  Hereinafter, some embodiments of the fuel injection control device will be described with reference to the drawings. In each embodiment, configurations that perform the same or similar operations are denoted by the same or similar reference numerals, and description thereof will be omitted as necessary.

(First embodiment)
First, the configuration of the fuel injection control system 1 will be described with reference to FIG. The fuel injection control system 1 includes a fuel injection control device (hereinafter referred to as a control device) 2 based on an ECU (Electronic (Engine) Control Unit) 2, a feed pump 3, a high-pressure fuel pump 4, a common rail 5, a crank angle sensor 6, and a fuel. The injectors 7 to 10 and the internal combustion engine 11 are mainly provided.

  The control device 2 controls fuel supply to the fuel chambers of the cylinders # 1 to # 4 of the internal combustion engine 11 by individually controlling the fuel injection devices 7 to 10. In the present embodiment, an example in which the internal combustion engine 11 has four cylinders is shown, but it may have six cylinders, and the number is not limited to this. Further, among the four cylinders, two cylinders # 1 and # 4 will be referred to as a first bank, and two cylinders # 2 and # 3 will be referred to as a second bank.

  The feed pump 3 pumps the fuel stored in the fuel tank 12 to the high-pressure fuel pump 4. The high-pressure fuel pump 4 is, for example, a plunger type pump. The high-pressure fuel pump 4 is driven by a pump drive unit 60 (see later) of the control device 2 using the output shaft of the internal combustion engine 11. The high-pressure fuel pump 4 boosts the low-pressure fuel supplied from the feed pump 3 into high-pressure fuel and supplies it to the common rail 5 through the high-pressure fuel pipe 13. The common rail 5 is provided to supply fuel to the fuel injection devices 7-10. The common rail 5 temporarily stores the high-pressure fuel supplied from the high-pressure fuel pump 4, and distributes the high-pressure fuel to each of the fuel injectors 7 to 10 through the high-pressure pipe 16 while maintaining the high pressure.

  The common rail 5 is equipped with a pressure sensor 14. The pressure sensor 14 detects the fuel pressure accumulated in the common rail 5 and outputs this detection signal to the control device 2. The crank angle sensor 6 is configured by being combined with the signal rotor 15, and detects the rotation of a crankshaft (not shown) inside the internal combustion engine 11. The signal rotor 15 has, for example, a disc shape and rotates integrally with, for example, the crankshaft of the internal combustion engine 11. A large number of protrusions are formed on the outer peripheral portion of the signal rotor 15, and the crank angle sensor 6 outputs a crank angle signal corresponding to the approach and separation of the protrusions of the signal rotor 15.

  The control device 2 can calculate the engine speed in response to receiving the crank angle signal of the crank angle sensor 6. The control device 2 changes and controls the torque for rotating the crankshaft in accordance with the change in the sensor signal S. The control device 2 controls fuel injection through the fuel injection devices 7 to 10 based on various sensor signals S including a crank angle signal.

<Basic configuration and operation description of the fuel injection devices 7 to 10>
Hereinafter, basic configurations and operations of the fuel injection devices 7 to 10 will be described. The fuel injection devices 7 to 10 are provided for injecting fuel into the cylinders of the internal combustion engine 11, and are also called injectors or fuel injection valves.

  Each of the fuel injection devices 7-10 is equipped with a built-in pressure sensor 7a-10a. The fuel injection devices 7 to 10 have the same structure. Therefore, hereinafter, the structure of the fuel injection device 7 will be described with reference to FIG. 2, and the structure description of the fuel injection devices 8 to 10 will be omitted.

  As shown in FIG. 2, the fuel injection device 7 includes first to fourth members 21 to 24, a nozzle needle 25, a spring 26 for the nozzle needle 25, a hydraulic driven valve 27, a spring 28 for the hydraulic driven valve 27, a The 1st valve 29, the 2nd valve 30, the 1st solenoid 31, the 2nd solenoid 32, the 1st spring 33, the 2nd spring 34, etc. are mainly provided.

  The first member 21 includes a first high pressure fuel flow path 35, a low pressure chamber 36, and a low pressure passage 37. When the first to third members 21 to 23 are assembled, the first high pressure fuel flow path 35 is configured to penetrate through the first to third members 21 to 23. The first high-pressure fuel passage 35 is connected to the common rail 5 through the high-pressure pipe 16, and the high-pressure fuel is supplied from the common rail 5 through the high-pressure pipe 16.

  The low-pressure chamber 36 provided in the first member 21 is configured to communicate with the third passage 39 from the opening on the second member 22 side when the first valve 29 is opened, and is closed when the first valve 29 is closed. The third passage 39 is configured to be blocked. The low-pressure chamber 36 is configured to communicate with the second passage 41 from the opening on the second member 22 side when the second valve 30 is opened, and is connected to the second passage 41 when the second valve 30 is closed. Is configured to be shut off.

  The low pressure chamber 36 is sealed around the opening on the second member 22 side between the first member 21 and the second member 22. A low pressure passage 37 is connected to the low pressure chamber 36. A low pressure pipe 38 shown in FIG. 1 is connected to the low pressure passage 37. The low-pressure fuel inside the low-pressure chamber 36 flows out from the low-pressure chamber 36 and is returned to the fuel tank 12 via the low-pressure passage 37 and the low-pressure pipe 38.

  A first valve 29, a second valve 30, a first solenoid 31, a second solenoid 32, a first spring 33, and a second spring 34 are arranged inside the low pressure chamber 36 of the first member 21.

  Usually, the first spring 33 is arranged so as to bias the first valve 29 in the direction of approaching the third passage 39. In this case, since the first valve 29 is closed, the low pressure chamber 36 and the third passage 39 are shut off from each other. The second spring 34 is arranged so as to urge the second valve 30 in a direction to approach the second passage 41. In this case, since the second valve 30 is closed, the low pressure chamber 36 and the second passage 41 are shut off from each other.

  The first solenoid 31 generates an electromagnetic force when energized, and repels the biasing force of the first spring 33 to separate the first valve 29 from the second member 22. Accordingly, the first solenoid 31 is energized to drive the first valve 29 to open, and the first valve 29 is opened to allow communication between the low pressure chamber 36 and the third passage 39.

  The second solenoid 32 generates an electromagnetic force when energized, and repels the urging force of the second spring 34 to separate the second valve 30 from the second member 22. Accordingly, the second solenoid 32 can be energized to drive the second valve 30 to open, and the second valve 30 to open allows the low pressure chamber 36 and the second passage 41 to communicate with each other.

  The second member 22 has a third passage 39, an intermediate chamber 40, and a second passage 41, and further has a second high-pressure fuel passage 35 a branched from the first high-pressure fuel passage 35. . The high-pressure fuel is branched and supplied from the first high-pressure fuel passage 35 to the second high-pressure fuel passage 35a. The second high-pressure fuel flow path 35a includes a third orifice 35aa and is connected to the annular chamber 42. The third orifice 35aa limits the flow rate of the high pressure fuel flowing through the second high pressure fuel flow path 35a. The structure itself of the second high-pressure fuel flow passage 35a is the third because the second high-pressure fuel flow passage 35a is provided with a plurality of third orifices 35aa and the flow passage area of the second high-pressure fuel flow passage 35a is small. It may be configured as the orifice 35aa.

  The second passage 41 includes a second orifice 41 a, and connects the low pressure chamber 36 and the first control chamber 43 without interposing the inside of the hydraulic driven valve 27. The second passage 41 may include a plurality of second orifices 41a, or the structure of the second passage 41 may be configured as the second orifice 41a due to the small passage area of the second passage 41. good.

  The annular chamber 42 is configured in an annular shape and is configured to communicate with the first control chamber 43 through the opening on the third member 23 side. A first control chamber 43 is formed in the third member 23. The first control chamber 43 is arranged in contact with the second member 22 and has a partial opening on the side of the second member 22. The periphery of this opening is sealed between the second member 22 and the third member 23. A connection passage 44 is connected to the first control chamber 43. The connection passage 44 connects the passage between the first control chamber 43 and the second control chamber 49. The connection passage 44 includes a fourth orifice 44 a, and the fourth orifice 44 a limits the flow rate of the fuel flowing through the connection passage 44. The connection passage 44 may be provided with a plurality of fourth orifices 44a, and the structure of the connection passage 44 itself has the function of the fourth orifice 44a by setting the flow passage area of the connection passage 44 to be small. It may be.

  A hydraulic driven valve 27 is arranged inside the first control chamber 43. The hydraulic driven valve 27 has a cylindrical shape. The cylindrical hydraulic driven valve 27 is configured such that the first passage 45 penetrates in the central axis direction. The first passage 45 includes a first orifice 45a. The first orifice 45a limits the flow rate of fuel flowing through the first passage 45. The first passage 45 may include a plurality of first orifices 45a, or the first passage 45 may have the function of the first orifice 45a by setting the passage area of the first passage 45 to be small. .

  Inside the first control chamber 43, a spring 28 for urging the hydraulic driven valve 27 in a direction of approaching the second member 22 is arranged. When the hydraulic driven valve 27 is in contact with the second member 22, the intermediate chamber 40 communicates with the first control chamber 43 via the first passage 45 and the first orifice 45a, but the third member of the annular chamber 42. The opening on the side of 23 is closed by the hydraulic driven valve 27.

  For example, as shown in FIG. 3, when the hydraulic driven valve 27 is separated from the second member 22, the intermediate chamber 40 is communicated with the first control chamber 43 without passing through the first passage 45, and the annular chamber 42 is also connected. It communicates with the first control room 43. As shown in FIGS. 2 and 3, the second passage 41 is configured to communicate with the first control chamber 43 without the hydraulic driven valve 27. The second passage 41 directly connects the low pressure chamber 36 and the first control chamber 43 regardless of the position of the hydraulic driven valve 27, that is, the lift state of the hydraulic driven valve 27.

  As shown in FIG. 2, the fourth member 24 includes a high pressure chamber 46, an injection hole 47, a cylinder 48, and a second control chamber 49. The high pressure fuel is supplied to the high pressure chamber 46 through the first high pressure fuel flow path 35. A nozzle needle 25 is arranged inside the fourth member 24. The tip end of the nozzle needle 25 is formed in a conical shape and the base end is formed in a cylindrical shape, and the high pressure chamber 46 is arranged so as to cover the side surface thereof. The cylinder 48 supports the nozzle needle 25 so that it can slide back and forth in the vertical direction of FIG. A second control chamber 49 is arranged behind the nozzle needle 25. The second control chamber 49 is connected to the first control chamber 43 through the connection passage 44.

  Inside the second control chamber 49, a spring 26 that urges the nozzle needle 25 in the direction of pressing it against the injection hole 47 is arranged. The first control chamber 43 and the second control chamber 49 form a control chamber. The injection hole 47 is configured to communicate with the cylinder of the internal combustion engine 11.

  When the pressure inside the second control chamber 49 is higher than a predetermined pressure, the nozzle needle 25 keeps the high pressure chamber 46 and the injection hole 47 blocked, or the nozzle needle 25 closes the injection hole 47. Moving. On the contrary, when the pressure in the second control chamber 49 is equal to or lower than the predetermined pressure, the nozzle needle 25 moves toward the third member 23, that is, in the upward direction in the drawing. In this case, the high pressure fuel is injected from the inside of the high pressure chamber 46 through the injection hole 47. Therefore, based on the pressure inside the first control chamber 43 and the second control chamber 49, the high pressure chamber 46 and the cylinder of the internal combustion engine 11 can be communicated / cut off.

<Explanation of Pressure Change in Each Chamber Inside Fuel Injection Devices 7-10>
The fuel injection control system 1 operates by setting various modes, and the control device 2 controls the injection of fuel from the injection holes 47 of each of the fuel injection devices 7 to 10 based on this mode, and controls the fuel injection. By controlling the discharge of fuel to the fuel tank 12 through the injectors 7 to 10, the internal pressure of the common rail 5 can be lowered. Hereinafter, the pressure change of each chamber inside the fuel injection devices 7 to 10 due to the opening / closing operation of the first valve 29 and the second valve 30 in each mode will be described.

  First, it is assumed that the urging force of the first spring 33 and the urging force of the second spring 34 act to close both the first valve 29 and the second valve 30. When the first valve 29 is closed, the third passage 39 and the low pressure chamber 36 are shut off from each other. Further, when the second valve 30 is closed, the connection between the second passage 41 and the low pressure chamber 36 is shut off. In such an initial state, the insides of the second control chamber 49, the first control chamber 43, the intermediate chamber 40, the third passage 39, and the second passage 41 are sealed, and the fuel pressures inside these are all in a high pressure state. Balance with. Therefore, the injection hole 47 is closed. Further, the hydraulic driven valve 27 comes into contact with the second member 22 by being biased by the spring 28.

<Low injection rate mode>
Hereinafter, a change in the pressure state of each chamber inside the fuel injection devices 7 to 10 in the low injection rate mode in which fuel is injected into the internal combustion engine 11 relatively slowly from the injection hole 47 will be described. In this low injection rate mode, the control device 2 opens the first valve 29 while keeping the second valve 30 closed from the initial state, and then closes the first valve 29.

  When the first valve 29 opens, the third passage 39 and the low pressure chamber 36 communicate with each other. The low pressure chamber 36, the intermediate chamber 40, and the first control chamber 43 communicate with each other through the third passage 39. As a result, the first control chamber 43 and the intermediate chamber 40 are reduced in pressure, and the intermediate chamber 40 is reduced in pressure to the same level as the low pressure chamber 36.

  Further, although the fuel accumulated in the first control chamber 43 flows to the intermediate chamber 40 side through the first passage 45, the flow rate of the fuel through the first orifice 45a is limited by the action of the first orifice 45a. To be done. At this time, the first passage 45 causes a pressure difference before and after the first orifice 45a. As a result, the first control chamber 43 is maintained at the medium pressure state.

  Due to the action of the fuel pressure inside the first control chamber 43, the hydraulic driven valve 27 is attracted to the intermediate chamber 40 side of the second member 22. Since the opening of the annular chamber 42 on the side of the third member 23 is closed by the hydraulic driven valve 27, the cutoff state between the second high pressure fuel flow path 35a and the first control chamber 43 is maintained.

  Since the pressure in the first control chamber 43 is in the medium pressure state, the pressure in the second control chamber 49 also changes to the medium pressure state. Then, the high-pressure fuel acts on the nozzle needle 25 through the first high-pressure fuel flow path 35 and slides the nozzle needle 25 along the cylinder 48 toward the second control chamber 49. As a result, the nozzle needle 25 is opened and high-pressure fuel is injected from the injection hole 47. At this time, since the flow path of the fuel through the first orifice 45a is limited to a relatively narrow range, the speed at which the first control chamber 43 reaches the intermediate pressure state also becomes slow. As a result, the valve opening speed of the nozzle needle 25 becomes relatively slow, and the change in the fuel injection amount over time, that is, the injection rate is relatively low.

  After that, when the first valve 29 is closed, the third passage 39, the intermediate chamber 40, the second passage 41 and the first control chamber 43 are closed, but the fuel in the first control chamber 43 is the first orifice 45a. Through to the intermediate chamber 40 and the third passage 39. On the other hand, since a pressure difference is generated between the annular chamber 42 and the first control chamber 43, the hydraulic driven valve 27 is set so that the fuel in the second high pressure fuel flow passage 35a repels the biasing force of the spring 28 through the annular chamber 42. Press.

  As a result, the lift amount of the hydraulic driven valve 27 decreases, and the high-pressure fuel flows into the first control chamber 43 and the second control chamber 49 through the annular chamber 42, and as a result, the first control chamber 43 and the second control chamber 49 are separated. Increase the pressure. When the internal pressure of the first control chamber 43 and the second control chamber 49 changes to a high pressure state that is approximately the same as the pressure of the first high pressure fuel flow path 35, the urging force of the spring 28 acts and the hydraulic driven valve 27 causes the second member to move. 22 side is contacted. As a result, the hydraulic driven valve 27 closes the gap between the annular chamber 42 and the first control chamber 43 and returns to the initial state.

<High injection rate mode>
Hereinafter, a change in the pressure state of each chamber inside the fuel injection device 7 in the high injection rate mode when fuel is injected at high speed from the injection hole 47 will be described. In the high injection rate mode, the control device 2 controls the first valve 29 and the second valve 30 to be opened almost simultaneously from the initial state.

  When the first valve 29 and the second valve 30 are opened substantially at the same time, the third passage 39 and the low pressure chamber 36 are communicated with each other, and the second passage 41 and the low pressure chamber 36 are also communicated with each other. Therefore, the low pressure chamber 36, the intermediate chamber 40, and the first control chamber 43 communicate with each other through the third passage 39 and the second passage 41. As a result, the first control chamber 43 and the intermediate chamber 40 have a low pressure.

  At this time, the pressure in the intermediate chamber 40 is reduced to the same level as that of the low pressure chamber 36, but the pressure can be quickly reduced compared to the case where only the first valve 29 described above is opened. Further, although the fuel accumulated in the first control chamber 43 flows to the side of the intermediate chamber 40 through the first passage 45, the flow rate of the fuel is limited because the first orifice 45a acts. At this time, the first passage 45 causes a pressure difference before and after the first orifice 45a.

  On the other hand, the fuel inside the first control chamber 43 flows into the low pressure chamber 36 also via the second passage 41. At this time, the second orifice 41a acts and the flow rate of the fuel through the second orifice 41a is also limited. The second passage 41 causes a pressure difference before and after the second orifice 41a. As a result, the first control chamber 43 is maintained in the medium pressure state.

  At this time, the hydraulic driven valve 27 is attracted to the intermediate chamber 40 side of the second member 22 by the action of the fuel pressure inside the first control chamber 43. Since the opening of the annular chamber 42 on the side of the third member 23 is closed by the hydraulic driven valve 27, the cutoff state between the second high pressure fuel flow path 35a and the first control chamber 43 is maintained.

  When the first control chamber 43 is in the medium pressure state, the pressure in the second control chamber 49 is also changed to the medium pressure state. Since the first control chamber 43 and the second control chamber 49 are in the intermediate pressure state, when the high-pressure fuel acts on the nozzle needle 25 through the first high-pressure fuel flow path 35, the nozzle needle 25 moves along the cylinder 48 as described above. And slides toward the second control chamber 49. As a result, the nozzle needle 25 is opened and high-pressure fuel is injected from the injection hole 47. At this time, the flow path of the fuel through the first orifice 45a and the second orifice 41a is widely restricted as compared with the low injection rate mode described above, so that the speed at which the first control chamber 43 reaches the intermediate pressure state is also high. Become. As a result, the valve opening speed of the nozzle needle 25 becomes relatively high, and the change in the fuel injection amount over time, that is, the injection rate becomes relatively high.

  After that, even if the second valve 30 is closed, the internal hydraulic pressure in each chamber such as the first control chamber 43 does not change substantially. Flows into the intermediate chamber 40 and the third passage 39 through the first orifice 45a. At this time, the third passage 39, the intermediate chamber 40, the second passage 41, and the first control chamber 43 are sealed, and the intermediate chamber 40 and the first control chamber 43 are in an intermediate pressure state.

  Since a pressure difference is generated between the annular chamber 42 and the first control chamber 43, the hydraulic driven valve 27 is pressed so that the fuel in the second high-pressure fuel passage 35a repels the biasing force of the spring 28 through the annular chamber 42. As a result, the lift amount of the hydraulic driven valve 27 decreases, and the high-pressure fuel flows into the first control chamber 43 and the second control chamber 49 through the annular chamber 42, and as a result, the first control chamber 43 and the second control chamber 49 are separated. Increase the pressure. When the internal pressure of the first control chamber 43 and the second control chamber 49 changes to a high pressure state that is approximately the same as the pressure of the first high pressure fuel flow path 35, the urging force of the spring 28 acts and the hydraulic driven valve 27 causes the second member to move. 22 side is contacted. As a result, the hydraulic driven valve 27 closes the gap between the annular chamber 42 and the first control chamber 43 and returns to the initial state.

<Description of Difference in Lifting Speed of Nozzle Needle 25 Based on Opening / Closing State of Second Valve 30>
When the first valve 29 and the second valve 30 are opened substantially at the same time, the internal pressure of the first control chamber 43 is reduced more quickly than when only the first valve 29 is opened. Therefore, when the first valve 29 and the second valve 30 are opened substantially at the same time, the lift speed of the nozzle needle 25 is faster than when only the first valve 29 is opened. Therefore, when the first valve 29 and the second valve 30 are simultaneously opened, the injection rate can be increased as compared with the case where only the first valve 29 is opened.

<Boot injection mode>
Hereinafter, a pressure change in each chamber of the fuel injection device 7 in the boot injection mode will be described. In the boot injection mode, the fuel injection devices 7 to 10 inject fuel from the injection holes 47 by gradually increasing the injection rate. In the boot injection mode, the control device 2 controls to open the first valve 29 and then the second valve 30 from the above-mentioned initial state.

  First, when the first valve 29 is opened, the third passage 39 and the low pressure chamber 36 communicate with each other. Therefore, the low pressure chamber 36, the intermediate chamber 40, and the first control chamber 43 communicate with each other through the third passage 39. As a result, the first control chamber 43 and the intermediate chamber 40 have a low pressure. At this time, the intermediate chamber 40 is reduced in pressure to the same level as the low pressure chamber 36. Further, although the fuel accumulated in the first control chamber 43 flows to the side of the intermediate chamber 40 through the first passage 45, the first orifice 45a acts, so that the flow rate of the fuel through the first orifice 45a is limited. . At this time, the first passage 45 causes a pressure difference before and after the first orifice 45a, and the first control chamber 43 is maintained at an intermediate pressure state. Due to the action of the fuel pressure inside the first control chamber 43, the hydraulic driven valve 27 is attracted to the intermediate chamber 40 side of the second member 22. Since the opening of the annular chamber 42 on the side of the third member 23 is closed by the hydraulic driven valve 27, the cutoff state between the second high pressure fuel flow path 35a and the first control chamber 43 is maintained.

  Then, similarly to the above, the high-pressure fuel acts on the nozzle needle 25 through the first high-pressure fuel flow path 35 and slides the nozzle needle 25 along the cylinder 48 toward the second control chamber 49. As a result, the injection hole 47 is opened and high-pressure fuel is injected from the injection hole 47. At this time, the flow path of the fuel through the first orifice 45a is restricted to be relatively narrow, so that the speed at which the pressure in the first control chamber 43 is reduced becomes slow. As a result, the valve opening speed of the nozzle needle 25 becomes relatively slow, and in the initial period of the boot injection mode, the change in the fuel injection amount over time, that is, the injection rate becomes relatively low. After that, when the second valve 30 is opened, the fuel in the first control chamber 43 flows into the low pressure chamber 36 also via the second passage 41. At this time, the second orifice 41a acts to limit the flow rate of fuel through the second orifice 41a. At this time, the second passage 41 has a pressure difference before and after the second orifice 41a.

  Since the flow path of the fuel through the first orifice 45a and the second orifice 41a becomes wider than that in the initial period of the boot injection mode, the speed of the first control chamber 43 lowering to reach the intermediate pressure state also increases. As a result, the valve opening speed of the nozzle needle 25 becomes relatively high, and the change in the fuel injection amount over time, that is, the injection rate becomes relatively large.

  After that, even if the second valve 30 is closed, the internal hydraulic pressure in each chamber such as the first control chamber 43 does not change substantially. Flows into the intermediate chamber 40 and the third passage 39 through the first orifice 45a. Then, the third passage 39, the intermediate chamber 40, the second passage 41, and the first control chamber 43 are sealed, and the intermediate chamber 40 and the first control chamber 43 are in a medium pressure state.

  Since a pressure difference is generated between the annular chamber 42 and the first control chamber 43, the hydraulic driven valve 27 is pressed so that the fuel in the second high-pressure fuel passage 35a repels the biasing force of the spring 28 through the annular chamber 42. As a result, the lift amount of the hydraulic driven valve 27 decreases, and the high-pressure fuel flows into the first control chamber 43 and the second control chamber 49 through the annular chamber 42, and as a result, the first control chamber 43 and the second control chamber 49 are separated. Increase the pressure. When the internal pressure of the first control chamber 43 and the second control chamber 49 changes to a high pressure state that is approximately the same as the pressure of the first high pressure fuel flow path 35, the urging force of the spring 28 acts and the hydraulic driven valve 27 causes the second member to move. 22 side is contacted. As a result, the hydraulic driven valve 27 closes the gap between the annular chamber 42 and the first control chamber 43 and returns to the initial state.

<Rail decompression mode, full decompression mode>
Hereinafter, the rail depressurization mode and the full depressurization mode will be described with reference to FIG. In order to reduce the internal pressure of the common rail 5, a rail depressurization mode and a full depressurization mode are provided. In the rail depressurization mode, the control device 2 controls the second valve 30 to be opened by the second solenoid 32 while keeping the first valve 29 closed by the first solenoid 31 from the initial state and being held in the closed state.

  As described above, in the initial state, the hydraulic driven valve 27 is biased by the spring 28, and the hydraulic driven valve 27 is in contact with the second member 22. When the second valve 30 is opened in this state, the accumulated fuel in the first control chamber 43 is discharged to the low pressure chamber 36 through the second passage 41, and the internal pressure of the first control chamber 43 becomes low.

  The accumulated fuel in the second high-pressure fuel passage 35a presses the hydraulic driven valve 27 through the annular chamber 42, the hydraulic driven valve 27 is separated from the second member 22, and the lift amount is reduced. Then, the first control chamber 43 and the intermediate chamber 40 communicate with each other. Since the pressure in the intermediate chamber 40 becomes the same level as the pressure in the first control chamber 43, the hydraulic driven valve 27 is not attracted to the intermediate chamber 40 by receiving the fuel pressure from the second high pressure fuel passage 35a. Therefore, the fuel flows from the common rail 5 into the low pressure chamber 36 through the first high pressure fuel flow passage 35, the second high pressure fuel flow passage 35a, the first control chamber 43, and the second passage 41, and the fuel flows from the low pressure chamber 36 through the low pressure pipe 38. It is discharged to the tank 12. See the fuel flow indicated by the arrow in FIG.

  Further, the fuel flow rate flowing into the first control chamber 43 via the third orifice 35aa of the second high pressure fuel flow path 35a becomes larger than the fuel flow rate flowing out to the low pressure chamber 36 via the second orifice 41a of the second passage 41. Is set. Therefore, the amount of fuel flowing into the first control chamber 43 from the second high-pressure fuel passage 35a is larger than the amount of fuel discharged from the first control chamber 43.

  As a result, the fuel pressure in the first control chamber 43 and the second control chamber 49 does not drop, and the nozzle needle 25 does not slide along the cylinder 48. As a result, the high pressure chamber 46 and the injection hole 47 can be maintained in a state of being blocked by the nozzle needle 25. As a result, the fuel can be discharged from the low pressure chamber 36 without injecting the fuel into the internal combustion engine 11 from the injection hole 47, and the internal pressure of the common rail 5 can be reduced.

  As described above, in the rail depressurization mode, the internal pressure of the common rail 5 can be reduced by using at least one fuel injection device (for example, 7). A mode in which the processing operation of the rail pressure reduction mode is executed using all the fuel injection devices 7 to 10 is referred to as a full pressure reduction mode. In this full decompression mode, the internal pressure of the common rail 5 can be quickly reduced by using all the fuel injection devices 7 to 10.

<Description of electrical configuration of control device 2>
Next, a drive system circuit of the fuel injection devices 7 to 10 will be described. FIG. 4 schematically shows the electrical configuration of the control device 2.
The control device 2 operates by being supplied with the power supply voltage VB from the battery. Here, a specific example of the power supply voltage VB of 12V system is shown, but it may be 24V system and can be changed appropriately. The control device 2 includes a microcomputer (hereinafter referred to as a microcomputer) 51, a first control IC 52, a second control IC 53, a first booster circuit 54, a second booster circuit 55, first valve drive units 56 and 57, and a second valve. The driving units 58 and 59 and the pump driving unit 60 are provided. The first control IC 52 corresponds to the first control unit, and the second control IC 53 corresponds to the second control unit.

  The first valve drive unit 56 is provided for driving the first valves 29 of the fuel injection devices 7 and 10 corresponding to the cylinders # 1 and # 4 of the first bank, and the first valve drive unit 57 is the second bank. Are provided for driving the first valves 29 of the fuel injection devices 8 and 9 corresponding to the cylinders # 2 and # 3. The second valve drive unit 58 is provided for driving the second valves 30 of the fuel injection devices 7 and 10 corresponding to the cylinders # 1 and # 4 of the first bank, and the second valve drive unit 59 is the second bank. Are provided for driving the second valves 30 of the fuel injection devices 8 and 9 corresponding to the cylinders # 2 and # 3.

  The microcomputer 51 is composed of, for example, an internal memory (not shown) including a CPU, a RAM, and a ROM, etc., and mainly executes various controls by executing a program stored in the internal memory. The microcomputer 51 outputs an injection signal based on an injection start command and an injection stop command to the first control IC 52 and the second control IC 53.

  Further, the microcomputer 51 can communicate with the first control IC 52 and the second control IC 53, respectively, using a serial communication line. The microcomputer 51 can change various setting values set in the memories of the first control IC 52 and the second control IC 53, whereby the microcomputer 51 integrally controls the first control IC 52 and the second control IC 53. There is. As will be described later in detail, the set value includes peak currents Ip and Ip2 that are maximum currents, pickup currents Ipa and Ipa2, constant currents Ipb and Ipb2, and their energization durations. The microcomputer 51 also outputs a pump control signal to the first control IC 52 using a dedicated line. The pump control signal indicates a control signal for controlling the high pressure fuel pump 4.

  Each of the first control IC 52 and the second control IC 53 is an integrated circuit device such as an ASIC, and includes a control body such as a logic circuit and a CPU, a memory such as a RAM, a ROM, and an EEPROM, and is based on hardware and software. To perform various controls.

  The first control IC 52 drives and controls the first booster circuit 54, the first valve drive units 56 and 57, and the pump drive unit 60. The first booster circuit 54 boosts the power supply voltage VB based on the booster control signal input from the first control IC 52, and outputs the first boosted voltage Vboost1 higher than the power supply voltage VB to the first valve drive units 56, 57 and the pump. It is supplied to the drive unit 60.

  FIG. 5 shows a configuration example of the first booster circuit 54. A resistor 73 is connected in series between the supply terminal of the power source voltage VB and the ground, between the coil 71 and the drain / source of the n-channel MOSFET 72. A diode 74 is forwardly connected from a common connection point of the coil 71 and the drain of the MOSFET 72 to the output node of the first boosted voltage Vboost1, and a charging capacitor 75 is connected between this output node and the source of the MOSFET 72. Therefore, when the first control IC 52 controls the turning on / off of the MOSFET 72, the energy accumulated in the coil 71 can be gradually accumulated in the charging capacitor 75 while flowing the current in the coil 71. As a result, the charging capacitor 75 can charge the first boosted voltage Vboost1 higher than the power supply voltage VB.

  FIG. 6 shows a circuit configuration of the first valve drive section 56. The first valve drive unit 56 is connected to the output terminals 2a to 2c of the control device 2 when driving the first valves 29 of the fuel injection devices 7 and 10 corresponding to the cylinders # 1 and # 4 of the first bank. The first solenoid 31 is cut off. Accordingly, the first control IC 52 controls the fuel injection timing by applying a current to the first solenoid 31 using the first valve drive unit 56.

  The first valve drive unit 56 is mainly composed of a discharge switch 81, a constant current switch 82, selection switches 83 and 84, and is further composed of a combination of current detection resistors 85 and 86 and diodes 87 to 90. The discharge switch 81 and the selection switches 83 and 84 are each composed of, for example, an n-channel type MOS transistor. The constant current switch 82 is composed of, for example, an n-channel type MOS transistor.

  The first boosted voltage Vboost1 charged in the charging capacitor 75 of the first booster circuit 54 is input to the drain of the MOS transistor that serves as the input terminal of the discharge switch 81. The discharge switch 81 supplies the first boosted voltage Vboost1 input to the input terminal according to the control signal given from the first control IC 52 to the control terminal of the discharge switch 81 from the output terminal side to the positive output terminal 2a of the control device 2. It can be energized.

  Between the input node of the power supply voltage VB and the positive output terminal 2a of the control device 2, the drain and source of the MOS transistor forming the constant current switch 82 and the anode and cathode of the diode 87 are connected in series. The diode 88 is reversely connected between the positive output terminal 2a of the control device 2 and the ground. The diodes 87 and 88 are provided for preventing energization from the positive output terminal 2a to the supply terminal side of the power supply voltage VB and from the positive output terminal 2a to the ground side, respectively.

  A first solenoid 31 for driving the first valve 29 of the fuel injection device 7 is connected between the positive output terminal 2a and the first negative output terminal 2b of the control device 2. The first solenoid 31 opens the first valve 29 of the fuel injection device 7 when energized. When the first solenoid 31 is de-energized, the first valve 29 is closed by the urging force of the first spring 33.

  A diode 89 is connected in the forward direction between the first negative output terminal 2b of the control device 2 and the output node of the first boosted voltage Vboost1 of the first booster circuit 54. The diode 89 is provided to feed back the stored energy based on the current flowing in the first solenoid 31 to the charging capacitor 75 of the first booster circuit 54 when the injection command is turned off.

  A first solenoid 31 for driving the first valve 29 of the fuel injection device 10 is connected between the positive output terminal 2a and the second negative output terminal 2c of the control device 2. The first solenoid 31 opens the first valve 29 of the fuel injection device 10 when energized, and closes the first valve 29 when energized.

  A diode 90 is forwardly connected between the second negative output terminal 2c of the control device 2 and the output node of the first boosted voltage Vboost1 of the first booster circuit 54. When the first control IC 52 receives an injection stop command as an injection signal from the microcomputer 51, the diode 90 stores the stored energy based on the current flowing in the first solenoid 31 into the charging capacitor 75 of the first booster circuit 54. It is provided for feedback charging.

  Between the first negative output terminal 2b of the control device 2 and the ground, the drain and source of the MOS transistor forming the selection switch 83 and the current detection resistor 85 are connected in series. Between the second negative output terminal 2c of the control device 2 and the ground, the drain and source of the MOS transistor forming the selection switch 84 and the current detection resistor 86 are connected in series.

  The selection switches 83 and 84 are provided to select the fuel injection devices 7 and 10 that inject fuel. The current detection resistor 85 detects the voltage of the current flowing through the first solenoid 31 of the fuel injection device 7 while the selection switch 83 is turned on. This detected value is input to the first control IC 52. The current detection resistor 86 detects the voltage of the current flowing through the first solenoid 31 of the fuel injection device 10 while the selection switch 84 is turned on. This detected value is input to the first control IC 52.

  The first control IC 52 performs on / off control of the discharge switch 81, the constant current switch 82, and the selection switches 83 and 84 based on the set value and the injection signal set by the microcomputer 51 and the detection current of the current detection resistor 85. . Since the first valve drive unit 56 is configured in this way, the first control IC 52 can control the electric current to be turned on and off through the first solenoid 31 by using the first valve drive unit 56, and each fuel injection device 7 can be controlled. It is possible to control the opening and closing of the first valves 29 of 10.

  The first valve drive unit 57 is connected to the output terminals 2a to 2c of the control device 2 when driving the first valves 29 of the fuel injection devices 8 and 9 corresponding to the cylinders # 2 and # 3 of the second bank. The first solenoid 31 is cut off. Accordingly, the first control IC 52 controls the fuel injection timing by energizing the first solenoid 31 using the first valve drive unit 57. The circuit configuration of the first valve drive unit 57 is the same as that of the first valve drive unit 56, and thus the description thereof is omitted.

  The pump drive unit 60 shown in FIG. 7 is provided to drive the high-pressure fuel pump 4. When driving the high-pressure fuel pump 4, the pump driving unit 60 disconnects the high-pressure fuel pump 4 by connecting and disconnecting the driving solenoid 61 of the high-pressure fuel pump 4 connected to the output terminals 2d to 2e of the control device 2. To drive.

  The pump drive unit 60 is mainly configured by a pump drive switch 91, a pump constant current switch 92, and a pump selection switch 93, and is configured by connecting a current detection resistor 94 and diodes 95, 96, 97 in the illustrated form. The pump drive unit 60 is configured to include one pump selection switch 93. The other configurations of the pump drive unit 60 are similar to the configuration of the first valve drive unit 56, and thus the wiring description will be omitted. The first control IC 52 can use the pump drive unit 60 to pass or disconnect the current to the driving solenoid 61 of the high-pressure fuel pump 4, and can drive and control the high-pressure fuel pump 4.

  The reference drawing is returned to FIG. 4 for explanation. The second control IC 53 drives and controls the second booster circuit 55 and the second valve drive units 58 and 59. The second booster circuit 55 boosts the power supply voltage VB based on the boosting control signal input from the second control IC 53 and supplies the second booster voltage Vboost2 higher than the power supply voltage VB to the second valve drive units 58 and 59. The circuit configuration of the second booster circuit 55 is the same as that of the first booster circuit 54. Therefore, the description of the circuit configuration is omitted. The value of the first boosted voltage Vboost1 of the first booster circuit 54 and the value of the second boosted voltage Vboost2 of the second booster circuit 55 may be the same or different from each other. The charging capacitor 75 of the second booster circuit 55 corresponds to the "charging unit" according to the present invention.

  The second valve drive unit 58 is connected to the output terminal of the control device 2 when driving the second valve 30 of the fuel injection device 7, 10 corresponding to the cylinders # 1, # 4 of the first bank. The solenoid 32 is cut off and turned on. The second control IC 53 applies a current to the second solenoid 32 of the second valve 30 of the fuel injection device 7, 10 corresponding to the cylinders # 1, # 4 of the first bank by using the second valve drive section 58. Therefore, the fuel injection rate is changed and controlled. The circuit configuration of the second valve drive unit 58 is the same as the circuit configuration of the first valve drive unit 56, and therefore description thereof will be omitted.

  The second valve drive unit 59 is a second solenoid connected to the output terminal of the control device 2 when driving the second valve 30 of the fuel injection devices 8 and 9 corresponding to the cylinders # 2 and # 3 of the second bank. The power is cut off to 32. The second control IC 53 uses the second valve drive unit 59 to apply a current to the second solenoid 32 of the second valve 30 of the fuel injection devices 8 and 9 corresponding to the cylinders # 2 and # 3 of the second bank. Therefore, the fuel injection rate is changed and controlled. The circuit configuration of the second valve drive unit 59 is the same as the circuit configuration of the first valve drive unit 56, and a description thereof will be omitted.

<Drive control processing of high-pressure fuel pump 4>
First, the basic pump drive processing by the high-pressure fuel pump 4 will be described with reference to FIG. When the fuel injection devices 7 ... 10 inject fuel from the injection holes 47, the pressure of the fuel accumulated in the common rail 5 decreases. The microcomputer 51 of the control device 2 detects the fuel pressure by the pressure sensor 14, and when the fuel pressure falls below the pressure lower limit threshold, outputs a boost command to the first control IC 52 as a pressure adjustment command signal. The first control IC 52 raises the internal pressure of the common rail 5 by driving and controlling the high-pressure fuel pump 4 using the pump driving unit 60. The drive control of the high-pressure fuel pump 4 is performed once for each crank angle of 180 ° CA as shown in FIG. As a result, the internal pressure of the common rail 5 can be adjusted to fall within the predetermined range.

  The circuit operation of the pump drive unit 60 will be described with reference to FIG. When the first control IC 52 receives a boost command as a pressure adjustment command signal from the microcomputer 51, the first control IC 52 controls the pump selection switch 93 to be ON and the pump drive switch 91 to be ON to drive the first boost voltage Vboost1 to the high pressure fuel pump 4. The power solenoid 61 is energized. The first control IC 52 turns off the pump drive switch 91 when the detection current of the current detection resistor 94 reaches the peak threshold value. After that, the drive current of the high-pressure fuel pump 4 decreases, but when the detection current of the current detection resistor 94 reaches the constant current range lower than the peak threshold value, the high-pressure fuel pump 4 is controlled by turning on / off the pump constant current switch 92. Drive current is maintained within a certain range. As a result, the operation of the high pressure fuel pump 4 is maintained. Then, when the first control IC 52 receives the boosting stop command of the pressure adjustment command signal from the microcomputer 51, it turns off all the switches 91 to 93 to stop the operation of the high-pressure fuel pump 4.

<Description of basic injection control processing>
Next, a basic injection control process will be described. When the internal combustion engine 11 has four cylinders and four cycles, single-injection injection or multi-stage injection such as three or five injections is performed within a crank angle range of 180 ° CA of crank angle signals before and after the top dead center TDC. For example, when injection is performed five times, each injection is referred to as pilot injection, pre-injection, main injection, after injection, and post injection. For example, when the injection is performed three times, the pre-injection and the post-injection are omitted and executed.

  When the control device 2 controls the injection of fuel into the cylinder of the internal combustion engine 11 through the injection holes 47 of the fuel injection devices 7 to 10, the microcomputer 51 outputs the injection start signal corresponding to each fuel injection device 7 to 10 It outputs to the control IC 52 and the second control IC 53.

  An example will be described in which the microcomputer 51 outputs the injection start signals of the injections M and M2 from the fuel injection device 7 corresponding to the cylinder # 1 to the first control IC 52 and the second control IC 53, respectively. The first control IC 52 energizes the first solenoid 31 to drive the first valve 29, thereby controlling the communication / blocking of the first orifice 45a. In parallel with the processing of the first control IC 52, the second control IC 53 uses the second valve drive unit 58 to energize the second solenoid 32 to drive the second valve 30 and thereby the second orifice 41 a of the second orifice 41 a. It controls communication / interruption and controls the fuel injection rate.

  FIG. 9 shows changes in the valve drive current flowing through the first solenoid 31 and the second solenoid 32. The first control IC 52 turns on the discharge switch 81 and the constant current switch 82 while turning on the selection switch 83.

  When the discharge switch 81, the constant current switch 82, and the selection switch 83 are turned on, the first boosted voltage Vboost1 of the charging capacitor 75 of the first booster circuit 54 is applied to the first solenoid 31. Therefore, the valve drive current increases. After that, when the valve drive current reaches the peak current Ip set in the microcomputer 51, the first control IC 52 detects the peak current Ip based on the voltage detected by the current detection resistor 85 and turns off the discharge switch 81. . Then, the valve drive current decreases and reaches the pickup current Ipa.

  When detecting that the valve drive current has reached the pickup current Ipa, the first control IC 52 holds the pickup current Ipa by controlling the on / off of the constant current switch 82. The pickup current Ipa is set lower than the peak current Ip, and is generated using the power supply voltage VB without using the boosted voltage Vboost1 charged in the charging capacitor 75 of the first booster circuit 54.

  After that, when the first control IC 52 finishes the command period Tp1 of the pickup current Ipa set by the microcomputer 51, the first control IC 52 further reduces the valve drive current from the pickup current Ipa to a predetermined constant value larger than 0. The constant current switch 82 is on / off controlled so as to hold the current Ipb. The predetermined constant current Ipb is set to be lower than the pickup current Ipa, and is generated using the power supply voltage VB without using the boosted voltage Vboost1 charged in the charging capacitor 75 of the first booster circuit 54. Thereafter, when the microcomputer 51 outputs an injection stop signal and the first control IC 52 receives this injection stop signal from the microcomputer 51, the constant current switch 82 is turned off to reduce the valve drive current.

  On the other hand, when the second control IC 53 receives the injection start signal, the second control IC 53 controls ON / OFF of the switches 81 to 83. As shown in the current waveform at the time of injection M2 in FIG. 9, the second control IC 53 controls the valve drive current to the peak current Ip2, and then controls the pickup current Ipa2 to be lower than this peak current Ip2, and then the pickup current Ipa2. It is controlled to a predetermined lower constant current Ipb2. The on / off control processing of the switches 81 to 83 executed by the second control IC 53 has the same contents as the on / off control processing of the switches 81 to 83 performed by the first control IC 52 described above, and therefore description thereof will be omitted. To do.

  The second control IC 53 generates the peak current Ip2 using the charging power charged in the charging capacitor 75 of the second booster circuit 55 and the second boosted voltage Vboost2 based on the on / off control of the discharge switch 81. In addition, the second control IC 53 generates the pickup current Ipa2 and the constant current Ipb2 by turning on / off the constant current switch 82 and the selection switch 83 while keeping the discharge switch 81 off. Therefore, the pickup current Ipa2 and the constant current Ipb2 are generated using the power supply voltage VB without using the charging power charged in the charging capacitor 75 of the second booster circuit 55 and the second boosted voltage Vboost2.

  Further, the microcomputer 51 sets the current setting values for driving the first valve 29 (peak current Ip, pickup current Ipa, constant current Ipb) to the current setting values for driving the second valve 30 (peak current Ip2, pickup current Ipa2, It is set independently of the constant current Ipb2). The microcomputer 51 also independently sets the energization time of these current set values in accordance with the characteristics of the first valve 29 and the second valve 30.

  However, the microcomputer 51 sets the on / off control timing of the switches 81 to 83 by the second control IC 53 to be the same as or different from the on / off control timing of the switches 81 to 83 by the first control IC 52. By setting to, the opening / closing control timing of the first valve 29 and the second valve 30 is adjusted. As a result, the fuel injection rate can be changed and controlled according to the above-mentioned mode. By performing such control, the control device 2 can inject fuel while changing the high injection rate mode, the low injection rate mode, and the boot injection mode described above.

<Normal decompression control>
Hereinafter, the processing operation when the control device 2 controls the internal pressure of the common rail 5 to be reduced will be described with reference to FIGS. 8 and 10.

  Normally, the control device 2 includes a fuel injection device 7 corresponding to the cylinder # 1 of the first bank, a fuel injection device 9 corresponding to the cylinder # 3 of the second bank, and a fuel injection device corresponding to the cylinder # 4 of the first bank. 10, the control process of the injection M is executed in the cycle of the fuel injection device 8, ... Corresponding to the cylinder # 2 of the second bank. Therefore, the fuel injection devices 7, 9, 10 and 8 perform main injection of fuel in this order. Note that FIG. 8 also shows other injections related to the multi-stage injection, but the description thereof is omitted because they are not related to the features of the present application.

  As shown in FIG. 8, after the control device 2 injects fuel from the fuel injection device 10 corresponding to the cylinder # 4 of the first bank, the control device 2 injects fuel from the fuel injection device 8 corresponding to the cylinder # 2 of the second bank. Consider the case where the pressure sensor 14 or the built-in pressure sensors 7a to 10a of the fuel injection devices 7 to 10 detect that the internal pressure of the common rail 5 exceeds the pressure upper limit threshold before injection. .

  At this time, the microcomputer 51 determines that there is a pressure reduction request in step S2 of FIG. The microcomputer 51 sets the energization condition of the second solenoid 32 that drives the second valve 30 in step S3 of FIG. 10, and outputs a decompression command to the second control IC 53 together with the energization condition of the second solenoid 32 as a pressure adjustment command signal. To do. The second control IC 53 opens the second valve 30 of interest by energizing the second solenoid 32 of interest in step S4 of FIG. 10 using the second valve drive units 58 and 59, thereby opening the second valve 30 of interest. The internal pressure of the common rail 5 is reduced in the rail depressurization mode.

  At timing t1 in FIG. 8, when a pressure reduction request is generated, since it is immediately before the fuel is injected from the fuel injection device 10 of the second bank # 2, the microcomputer 51 sets the target second solenoid 32 to the cylinder in step S4. The second solenoid 32 of the fuel injection devices 7 to 9 corresponding to the cylinders # 1 to # 3 other than # 4 is used. When the second solenoid 32 of each of the fuel injection devices 7 to 9 is energized, the internal pressure of the common rail 5 decreases in the rail depressurization mode. The microcomputer 51 energizes the target second solenoid 32 in steps S4 and S5 until it detects the signal from the pressure sensor 14 and reaches the target pressure.

  As shown in FIG. 8, during the fuel injection period t2 to t3 of the fuel injection device 8 corresponding to the cylinder # 2 of the second bank, the second control IC 53 controls the cylinder # 3 of the same bank as the cylinder # 2. In order to control the second valve 30 to be closed, the energization of the second solenoid 32 is temporarily stopped. This is because if the second valves 30 of the fuel injection devices 8 and 9 corresponding to the cylinders # 2 and # 3 of the same second bank are controlled to be opened at the same time, the fuel injection device 8 corresponding to the same second bank will be used. , 9 of the second solenoid 32 are energized at the same time, the amount of charge power consumed by the charging capacitor 75 of the second booster circuit 55 is significantly increased, and a large thermal stress is applied to the charging capacitor 75. This is because the operation reliability may be impaired.

  By controlling the second control IC 53 so that the second solenoids 32 of the fuel injection devices 8 and 9 corresponding to the same second bank are not energized at the same time, the thermal stress of the charging capacitor 75 can be reduced. After the fuel injection period t2 to t3 by the fuel injection device 8 has passed, the second control IC 53 again controls the second valves 30 of the fuel injection devices 8 and 9 corresponding to the second bank to be simultaneously opened, thereby the inside of the common rail 5 is controlled. Reduce pressure. See periods t3 to t6 in FIG.

  As shown in FIG. 8, after the timing t4, the fuel is injected using the fuel injection device 7 corresponding to the cylinder # 1 of the first bank, so that the first control IC 52 of the control device 2 causes the fuel injection device 7 to operate. During the fuel injection period t4 to t5, the second valve 30 of the fuel injection device 10 corresponding to the cylinder # 4 of the first bank is controlled to be closed. After timing t6 shown in FIG. 8, the fuel is injected by the fuel injection device 9 corresponding to the cylinder # 3 of the second bank, so the second control IC 53 of the control device 2 injects the fuel from the fuel injection device 9. After timing t6, the second valve 30 of the fuel injection device 8 corresponding to the cylinder # 2 of the same second bank is controlled to be closed.

  The microcomputer 51 detects the signals of the pressure sensor 14 and the built-in pressure sensors 7a to 10a, determines that the pressure reduction request is completed when the target pressure is reached, and stops energization of the target second solenoid 32 in step S6. See timing t7 in FIG. Subsequent processing is the same as the injection control processing in normal times.

  According to the present embodiment, in the period t1 to t4 during which the internal pressure of the common rail 5 is reduced, the second control IC 53 sets the same energization periods t1 to t2 and t3 to t6 of the second solenoid 32 in the target fuel injection device 9. The period is different from the energization periods t2 to t3 of the second solenoid 32 during normal injection control in the other fuel injection device 8 of the bank.

  Similarly, in the period t4 to t6 during which the internal pressure of the common rail 5 is decreased, the second control IC 53 sets the energization periods t1 to t4 and t5 to t7 of the second solenoid 32 in the target fuel injection device 10 to the same bank. The fuel injection device 7 has a period different from a part of the energization period t4 to t6 of the second solenoid 32 at the time of normal injection control.

  Therefore, even if the second control IC 53 controls the energization of the plurality of second solenoids 32 using the second boosted voltage Vboost2 of the same charging capacitor 75, the current load applied to the charging capacitor 75 can be dispersed. And can reduce heat stress. As a result, the internal pressure of the common rail 5 can be reduced without applying heat stress to the charging capacitor 75 as much as possible.

<Processing operation in case of abnormality>
In addition, a processing operation in the case where an abnormality occurs due to the high pressure fuel pump 4 having a sticking failure on the pressure feeding side will be described with reference to FIG. 11. When the microcomputer 51 of the control device 2 detects a full pressure feeding failure by detecting the values of the pressure sensor 14 and the built-in pressure sensors 7a to 10a as abnormal values, it shifts to the full depressurization mode and shifts to processing operation at the time of abnormality. To do.

  The microcomputer 51 outputs a stop command of the pressure adjustment command signal to the first control IC 52 and the second control IC 53 in the full decompression mode. Then, the first control IC 52 stops the drive control of the pump drive unit 60, and at the same time, the second control IC 53 sets all the fuel injection devices 7 to 10 as the target fuel injection devices 7 to 10 for the depressurization drive. By energizing the second solenoids 32 of 7 to 10, the second valve 30 is controlled to be opened.

  FIG. 11 shows an example in which the energization start processing of the second solenoids 32 for driving the second valves 30 of all the fuel injection devices 7 to 10 is simultaneously executed at the timing t11. At this time, the valve drive current is supplied to the second solenoids 32 of all the target fuel injection devices 7 to 10 via the second valve drive parts 58 and 59, so that the consumption amount of the charging power of the charging capacitor 75 is significantly increased. Will increase.

  In order to mitigate the effect of this rapid increase in the consumption of charging power, the second control IC 53 compares the peak current Ip2 that is applied to the second solenoid 32 of the target fuel injection device 7 to 10 with that during normal injection control. It may be set to be low, and the pickup current Ipa2 may be energized for a predetermined time Ta.

  The broken line in FIG. 12 shows the valve drive current at the time of normal injection control, and the solid line in FIG. 12 shows the valve drive current at the time of abnormality. The period Tp2b in which the pickup current Ipa2 is supplied is set to be longer than the period Tp2 during normal injection control by a predetermined time Ta. For example, the peak current Ip2 / 2 of the valve drive current at the time of abnormality is set to half the peak current Ip2 of the valve drive current at the time of normal injection control.

  The second control IC 53 sets the peak current to be supplied to the second solenoid 32 at the time of abnormality to be lower than the peak current Ip2 at the time of normal injection control, so that the transiently generated current is compared with the conventional technique. It can be suppressed and the thermal stress generated in the charging capacitor 75 can be reduced.

  Further, since the energization time of the pickup current Ipa2 is extended by the predetermined time Ta, the integrated amount of the energization current also increases. Since the opening degree of the second valve 30 is determined based on the integrated amount of the energization current, the second valve 30 can be reliably controlled to open so that it does not differ from that during normal injection control.

  Further, it is desirable to set the predetermined time Ta according to the characteristics of the fuel injection devices 7-10. For example, the mechanical or electrical characteristics of the fuel injection devices 7 to 10 are obtained in advance by experiments or simulations, and the correspondence map of the predetermined time Ta that matches these characteristics is stored in the internal memory of the second control IC 53 in a nonvolatile manner. It is good to do it. Then, the second control IC 53 refers to this correspondence map and controls the predetermined time Ta in accordance with the measured values of the peak current Ip2 / 2 and the pickup current Ipa2 to open the second valve 30 more reliably. You can control.

<Modification of processing during normal injection control>
In the above description, the peak current of the valve drive current at the time of abnormality is set lower than the peak current Ip of the valve drive current at the time of normal injection control, but when there is a pressure reduction request at the time of normal injection control. In addition, the second control IC 53 sets the peak current of the valve drive current lower than the peak current Ip in the normal injection control, and executes the control in which the time for energizing the pickup current Ipa2 is extended by the predetermined time Ta. It may be done. At this time, similarly to the above, the peak current Ip / 2 of the valve drive current may be set to half the peak current Ip during normal injection control, and the predetermined time Ta may be set longer. As a result, the same effect as described above is achieved.
In the above description, the peak current Ip / 2 of the valve drive current is set to half the peak current Ip of the valve drive current during the normal injection control when a pressure reduction request is made during the normal injection control or during an abnormality. Although shown, the amount is not limited to half.

<Modification of processing during normal injection control or abnormal time>
As another method, it is desirable to shift the energization timing of the peak current Ip2 by shifting the energization start timing of each second solenoid 32 for driving each second valve 30 of the fuel injection devices 7-10. For example, as shown at timing t21 in FIG. 13, after the second solenoids 32 for driving the respective second valves 30 of the fuel injection devices 7 and 10 are energized, at timing t22, each of the fuel injection devices 8 and 9 is driven. It is advisable to start energizing each second solenoid 32 for driving the two-valve 30. As a result, the transiently generated current can be suppressed as compared with the conventional one, and the thermal stress generated in the charging capacitor 75 of the second booster circuit 55 can be reduced. The second solenoids 32 of the fuel injection devices 8 and 9 may be energized prior to the second solenoids 32 of the fuel injection devices 7 and 10.
Conventionally, the pressure reducing valve is provided in the common rail 5, but if the fuel can be discharged from the low pressure chambers 36 of the fuel injection devices 7 to 10 as in the present embodiment, it is not necessary to provide the pressure reducing valve in the common rail 5. In addition to the configuration of the present embodiment, a common rail 5 may be provided with a pressure reducing valve.

(Second embodiment)
With reference to FIG. 14 and FIG. 15, a processing operation when the control device 2 controls to decrease the internal pressure of the common rail 5 will be described. As shown in FIG. 14, let us consider a case where the control device 2 causes a full-pressure feeding failure after the fuel is controlled to be injected from the fuel injection device 7 corresponding to the cylinder # 1 of the first bank.

  While the control device 2 is performing normal injection control in S11 of FIG. 15, when the microcomputer 51 determines that there is a pressure reduction request and no injection request in S12 and S13, the second valve 30 is turned on in S14 of FIG. The energization condition of the second solenoid 32 to be driven is set, and a pressure reduction command is output to the second control IC 53 together with the energization condition of the second solenoid 32 as a pressure adjustment command signal. The second control IC 53 energizes the target second solenoid 32 in S15 to open the target second valve 30, thereby reducing the internal pressure of the common rail 5 in the full decompression mode. After this, as shown in S16 to S18 of FIG. 15, if the internal pressure of the common rail 5 reaches the target pressure without an injection request, the control device 2 stops the energization of the target second solenoid 32, and thereby the full pressure reduction is performed. Exit the mode.

  However, when the injection request is generated based on the sensor signal S, the microcomputer 51 determines NO in S16, stops energization of the target second solenoid 32, returns the process to S11, and executes the processes of S11 to S13. repeat.

  At this time, since the control device 2 has shifted to the full decompression mode, the microcomputer 51 causes the first control IC 52 to cause the first valve drive unit 57 to cause the first solenoid 31 of the fuel injection device 9 to respond to the injection request. After starting energization and ending energization of the first solenoid 31, the second control IC 53 starts energizing the second solenoid 32 of the fuel injection device 9 by the second valve drive unit 59. See timings t31 and t32 in FIG.

  The first control IC 52 controls the peak current Ip, the pickup current Ipa, and the constant current Ipb using the set values set in the internal memory. The second control IC 53 controls the peak current Ip2, the pickup current Ipa2, and the constant current Ipb2 using the set values set in the internal memory.

  At timing t31, the internal values of the first control IC 52 and the second control IC 53 store the set values in each mode set in the microcomputer 51, such as the low injection rate mode and the high injection rate mode. .

  Therefore, the first control IC 52 controls the opening and closing of the first valve 29 according to the set value corresponding to each mode, and then the second control IC 53 opens and closes the second valve 30 according to the set value corresponding to each mode. You can control. The microcomputer 51 controls the opening / closing of the first valve 29 by the first control IC 52 to continue the injection control, and then controls the opening / closing of the second valve 30 by the second control IC 53 to lower the internal pressure of the common rail 5. Can be made.

  After that, the microcomputer 51 deenergizes the common rail 5 again by energizing the target second solenoid 32 in S14. See timings t32 to t33 in FIG. When an injection request corresponding to the sensor signal S is generated again, the microcomputer 51 stops energizing the target second solenoid 32 in S19, and shifts to normal control in S11. Since the above-mentioned set values are stored in advance in the internal memory of the first control IC 52 and the second control IC 53 by the microcomputer 51, the injection control is performed as usual in accordance with the requests of the low injection rate mode and the high injection rate mode. I can continue. See timings t33 to t34 in FIG.

According to this embodiment, after the first control IC 52 finishes energizing the first solenoid 31 for driving the first valve 29, the second control IC 53 shifts to the second solenoid 32 for driving the second valve 30. Energization has started.
While maintaining the controllability of the low / high injection rate in each mode, it is possible to control the opening / closing of the first valve 29 and the second valve 30 by sequentially energizing the first solenoid 31 and the second solenoid 32. It is possible to meet the pressure reduction request while ensuring the controllability of a high injection rate.

(Third Embodiment)
In the present embodiment, a method for controlling change of the peak current Ip at the time of abnormality will be described. When the control device 2 makes a pressure reduction request at the time of the above-described normal injection control or at the time of abnormality and reduces the internal pressure of the common rail 5, the second control IC 53 causes the normal injection control at the time of the normal injection control as shown in FIG. The pickup current Ipaa is controlled without controlling the peak current Ip. Then, the second control IC 53 can control the peak current Ipm to be the same as the pickup current Ipaa, as shown in FIG. As a result, the peak current Ipm can be made significantly lower than the peak current Ip during normal injection control.

  In this case, the second control IC 53 performs on / off control of the constant current switch 82 to energize the second solenoid 32 from the power supply voltage VB so as to reach the peak current Ipm. Is never used. As a result, the charging power of the charging capacitor 75 is not consumed, and the thermal stress applied to the charging capacitor 75 can be significantly reduced.

(Other embodiments)
The present disclosure is not limited to the above-described embodiments, and can be variously modified without departing from the gist thereof. For example, the following modifications or extensions are possible.

Although the fuel injection device 7 to 10 is configured to return the fuel to the fuel tank 12 through the low pressure pipe 38, the common rail 5 may be provided with a pressure reducing valve. When the pressure reducing valve is provided on the common rail 5, the pressure may be reduced from the pressure reducing valve or from the fuel injection devices 7 to 10.
When the common rail 5 is not provided with a pressure reducing valve, the pressure may be reduced from the fuel injection devices 7 to 10. As the pressure sensor 14, the built-in pressure sensors 7a to 10a of the fuel injection devices 7 to 10 may be used, or the pressure sensor 14 mounted on the common rail 5 may be used.

  The first control IC 52 and the second control IC 53 may be configured within an integrated circuit integrated with each other, may be configured within separate integrated circuits, or may be integrated with the microcomputer 51 to configure a control unit. You may. The first control chamber 43 and the second control chamber 49 may be configured as an integrated chamber.

Although the mode in which the N-channel type MOS transistor is used as each of the switches 81 to 84 and 91 to 93 is shown, the invention is not limited to this, and various transistors and switching elements can be applied.
Although only one second orifice 41a is provided in the second passage 41, a plurality of passages connecting the low pressure chamber 36 and the first control chamber 43 may be provided, and the second orifice 41a may be provided in these passages. You may respectively provide in several passages. That is, at least one second orifice 41a may be provided.

  Further, in the above-described embodiment, since the internal combustion engine 11 has four cylinders, two of the cylinders # 1 to # 4 corresponding to the plurality of fuel injection devices 7 to 10 are provided in each of the cylinders # 1 and # 4 of the first bank. , The form treated as the cylinders # 2 and # 3 of the second bank is shown, but the present invention is not limited to this. It can be applied even to 6 cylinders.

  The configurations of the respective embodiments can be appropriately combined and applied. A mode in which a part of the above-described embodiment is omitted as long as the problem can be solved can be regarded as the embodiment. Further, all possible modes can be regarded as the embodiments without departing from the essence of the invention specified by the wording recited in the claims.

  Although the present disclosure has been described based on the above-described embodiments, it is understood that the present disclosure is not limited to the embodiments and structures. The present disclosure also includes various modifications and modifications within an equivalent range. In addition, various combinations and forms, and other combinations and forms including one element, more, or less than them are also included in the scope and concept of the present disclosure.

  In the drawings, 2 is a fuel injection control device, 5 is a common rail, 7 to 10 are fuel injection devices, 11 is an internal combustion engine, 27 is a hydraulic driven valve, 29 is a first valve, 30 is a second valve, and 31 is a first solenoid. , 32 is a second solenoid, 36 is a low pressure chamber, 41 is a second passage, 41a is a second orifice, 43 is a first control chamber (control chamber), 45 is a first passage, 45a is a first orifice, and 47 is injection. A hole, 49 is a second control room (control room), 52 is a first control IC (first control unit), 53 is a second control IC (second control unit), and 75 is a charging capacitor (of the second booster circuit 55). The charging capacitor 75 corresponds to the "charging unit").

Claims (8)

A fuel injection control device for respectively controlling injection of the fuel from a common rail (5) where fuel is accumulated to an internal combustion engine (11) using a plurality of fuel injection devices (7 to 10),
Each of the plurality of fuel injection devices includes a first solenoid (31), a first valve (29), a second solenoid (32), and a second valve (30),
At the time of normal injection control, a first controller (52) for controlling the fuel injection timing by driving the first valve by energizing the first solenoid,
During the normal injection control, the peak current (Ip2) showing the maximum current is supplied to the second solenoid by using the charging power of the charging section (75), and then the pickup current (Ipa2) lower than the peak current is supplied. A second controller (53) that drives the second valve by energizing to control the injection rate of the fuel;
When the internal pressure of the common rail is reduced during the normal injection control or during an abnormality different from the normal injection control, the first control unit closes the first valve and the second control unit It is configured to control the opening of the second valve by energizing the second solenoid in at least one target fuel injection device of the plurality of fuel injection devices,
When reducing the internal pressure of the common rail during the normal injection control or during an abnormality different from the normal injection control, the second controller energizes the second solenoid of the target fuel injection device. A fuel injection control device that performs a control in which a peak current is set lower than that in the normal injection control and the pickup current is energized for a predetermined time.   The second control unit reduces the peak current by half when compared with the normal injection control when the internal pressure of the common rail is reduced during the normal injection control or during the abnormality. Fuel injection control device.   When lowering the internal pressure of the common rail during the normal injection control or during the abnormality, the second control unit does not perform the peak current control using the charging power of the charging unit (75). 2. The fuel injection control device according to claim 1, which controls the pickup current.   The fuel injection control device according to any one of claims 1 to 3, wherein the second control unit sets the predetermined time in accordance with the characteristics of the fuel injection device. A fuel injection control device for controlling injection of each of the fuels from a common rail in which fuel is accumulated to an internal combustion engine using a plurality of fuel injection devices,
Each of the plurality of fuel injection devices includes a first solenoid (31), a first valve (29), a second solenoid (32), and a second valve (30),
At the time of normal injection control, a first controller (52) for controlling the fuel injection timing by driving the first valve (29) by applying a current to the first solenoid,
During the normal injection control, the second valves (30) of the plurality of fuel injection devices (8, 9) are supplied by energizing the plurality of second solenoids with the same charging power of the charging unit (75). ), And a second controller (53) for changing and controlling the injection rate of the fuel.
When the internal pressure of the common rail is reduced during the normal injection control or during an abnormality different from the normal injection control, the first control unit closes the first valve and the second control unit It is configured to control the opening of the second valve by energizing the second solenoid in at least one target fuel injection device of the plurality of fuel injection devices,
In the period in which the internal pressure of the common rail is reduced, the second control unit sets the energization period of the second solenoid in the target fuel injection device to the second period during the normal injection control in another fuel injection device. A fuel injection control device having a period different from the energization period of the solenoid. When two banks of each of the plurality of cylinders provided corresponding to the plurality of fuel injection devices are set as one bank, respectively,
The fuel injection control device according to claim 5, wherein the second control unit controls differently the energization period of the second solenoids of the two fuel injection devices corresponding to the two cylinders of the same bank. When the first control unit energizes the first solenoid for driving the first valve during the abnormality,
After the first control unit finishes energizing the first solenoid for driving the first valve, the second control unit starts energizing the second solenoid for driving the second valve. The fuel injection control device according to claim 5 or 6. The fuel injection device,
A nozzle needle (25) for injecting the fuel supplied from the common rail through a high-pressure fuel flow path (35) through an injection hole (47), and accumulating the fuel at the back of the nozzle needle and for injecting the nozzle needle. A control chamber (43, 49) for controlling the fuel injected from a hole, a hydraulic driven valve (27) provided inside the control chamber and driven by the pressure of the high-pressure fuel passage and the control chamber, The first passage (45) provided inside the hydraulic driven valve inside the control chamber, the first orifice (45a) that limits the first passage, and the first passage (45a) that does not pass through the inside of the hydraulic driven valve. At least one or more second passages (41) connecting the control chamber and the low pressure chamber (36), and at least one or more second orifices (41a) limiting the second passages respectively; Wherein provided for discharging the fuel that is not injected from the injection hole low-pressure chamber (36), it is configured with,
The first control unit energizes the first solenoid to drive the first valve, and the second control unit energizes the second solenoid to drive the second valve, whereby the second orifice It is configured to control connection and disconnection,
When lowering the internal pressure of the common rail, the first solenoid controls the closing of the first valve and the second solenoid controls the opening of the second valve, so that the hydraulic driven valve is driven and the second valve is driven. By communicating the orifice and communicating the high-pressure fuel flow path, the control chamber, and the low-pressure chamber from the common rail, the fuel is supplied to the internal combustion engine without injecting the fuel from the injection hole of the nozzle needle. 8. The fuel injection control device according to claim 1, wherein the fuel injection control device is configured to flow out from the low pressure chamber to reduce the internal pressure of the common rail.

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