DE102019216069B4 - FUEL INJECTION CONTROL DEVICE - Google Patents

Abstract

A fuel injection control device configured to implement injection control for injecting fuel stored in a common rail (5) into an internal combustion engine (11) using a plurality of fuel injectors (7 to 10), each of the fuel injectors having a first Solenoid (31), a first valve (29), a second solenoid (32) and a second valve (30), wherein the fuel injection control device comprises: a first control section (52) configured to energize the first solenoid, to drive the first valve and control fuel injection timing under normal injection control; anda second control section (53) configured to apply a peak current (Ip2) indicative of a maximum current to the second solenoid using charging power of a charging section (75) and then to apply a pickup current (Ipa2) lower than that Peak current is to drive the second valve to control an injection ratio of the fuel under the normal injection control, wherein when an internal pressure of the common rail is reduced under the normal injection control or under an abnormal condition other than the normal injection control ,the first control section is configured to implement a control to close the first valve, andthe second control section is configured to energize the second solenoid for at least one targeted fuel injector among the fuel injectors and to implement a control to open the second valve ement, wherein when the internal pressure of the common rail is reduced under the normal injection control or under the abnormal condition different from the normal injection control, the second control section is configured to implement control to reduce the peak current applied to the second solenoid is energized for the target fuel injector to be set to be lower than the peak current under the normal injection control and to extend a time for applying the pickup current by a predetermined period of time.

Description

[Technical Field]

The present disclosure relates to a fuel injection control device.

BACKGROUND

The applicants have already proposed the fuel injection device that injects the fuel from a nozzle tip using two solenoid valves and controlling an oil pressure (see, for example, DE 10 2013 112 751 A1 ). The Indian DE 10 2013 112 751 A1 The injector described is able to inject the fuel from a nozzle at the tip using an actuator that uses a piezo stack.

The fuel injection control device each controls fuel injection from a common rail storing fuel to an internal combustion engine using a plurality of fuel injection devices. When the fuel injection control device controls oil pressure to control fuel injection using two solenoid valves (hereinafter referred to as first valve and second valve) in the fuel injection device (also referred to as injector), the fuel injection control device controls the first valve to control fuel injection timing control, and drives the second valve to control a fuel injection ratio. The fuel injection ratio can be changed by adjusting a speed for releasing a nozzle needle at the tip of the fuel injector.

When a pressure reduction request occurs during normal control, the fuel injection control device may reduce an internal pressure of the common rail by releasing the second valve of the fuel injection device. When a high-pressure fuel pump supplies high-pressure fuel to the fuel injection device and malfunctions occur due to sticking on the forced-feed side, the fuel injection control device can reduce the oil pressure in the oil pressure control chamber and prevents high-pressure abnormality by releasing the second valve. This makes it possible to adjust the fuel pressure to a target pressure even when a high-pressure pump malfunctions due to sticking on the forced-feed side during normal control.

For example, a four-cylinder internal combustion engine includes four fuel injectors. When the valve configuration mentioned above is used, two valves are provided for each of the four fuel injectors. Therefore, the fuel injection control device controls eight valves.

The second valves for all cylinders are opened simultaneously when a pressure reduction request occurs during the normal or abnormal operation as above. When the fuel injection control device provides control to simultaneously open the second valves for all cylinders, a load for supplying the power for driving increases and a thermal load increases. Normal operation may not be possible. One solution may be to increase the stored energy so that control can be provided to open the valves for all cylinders simultaneously. However, it is necessary to increase the capacitance values of a charging capacitor as a charging section in order to store energy. The solution is inconvenient as circuit size and complexity increase.

From the DE 10 2015 114 828 A1 a fuel injector with an indirectly actuated valve body for releasing and ending fuel injections is also known. The movement of the valve body is controlled by the pressure in a control chamber which provides the rear (dorsal) hydraulic support of the valve body. The fuel injector has a separating body which is arranged in the control chamber and divides the control chamber into a first dorsal section and a second distal section. A transfer throttle point can be formed in and or on the separating body, which dampens pressure oscillations that can occur when the valve body is lifted off a valve seat. This damping smoothes or linearizes the movement behavior of the valve body and the course of the injection rate at the beginning and/or at the end of an injection process. More fuel injectors are from the WO 2019 - 039 480 A1 and the JP 2002 - 054 522 A known.

EXECUTIVE SUMMARY

It is an object of the present disclosure to provide a fuel injection control device capable of reducing an internal pressure of a common rail without thermally stressing a charging portion as much as possible.

The object is achieved by a fuel injection control device according to claims 1 and 5, respectively. Advantageous developments are the subject of the subclaims.

According to an aspect of the present disclosure, a fuel injection control device is configured to implement injection control for injecting fuel stored in a common rail into an internal combustion engine using a plurality of fuel injection devices. Each of the fuel injectors includes a first solenoid, a first valve, a second solenoid, and a second valve. The fuel injection control device includes a first control portion configured to energize the first solenoid to drive the first valve and control fuel injection timing under normal injection control. The fuel injection device further includes a second control section configured to apply a peak current indicative of a maximum current to the second solenoid using charging energy of a charging section and then to apply a pickup current lower than the peak current to the second valve to control an injection ratio of the fuel under the normal injection control. When an internal pressure of the common rail is reduced under the normal injection control or under an abnormal condition different from the normal injection control, the first control section is configured to implement control to close the first valve, and the second control section is configured to energize the second solenoid for at least one targeted fuel injector among the fuel injectors and implement control to open the second valve. When the internal pressure of the common rail is reduced under the normal injection control or under the abnormal condition different from the normal injection control, the second control section is configured to implement control to reduce the peak current supplied to the second solenoid for setting the target fuel injector applied to be lower than the peak current under the normal injection control and extending a time for applying the pickup current by a predetermined period of time.

When the internal pressure of the common rail is reduced under the normal injection control or in an abnormal state, the first control section provides control to close the first valve, and the second control section energizes the second solenoid for at least one target fuel injector of the fuel injectors and energizes accordingly a control for opening the second valve ready.

When the internal pressure of the common rail is reduced under the normal injection control or in an abnormal state, the second control section provides control to adjust the peak current applied to the second solenoid for the target fuel injector to be is lower than the same under the normal injection control, and to lengthen the time for applying the pull-in current by a predetermined length of time. The invention according to claim 1 adjusts the peak current to be lower than that under the normal injection control. Therefore, it is possible to reduce an internal pressure on the common rail without thermally stressing the charging portion as much as possible.

According to an aspect of the present disclosure, a fuel injection control device is configured to implement injection control for injecting fuel stored in a common rail into an internal combustion engine using multiple fuel injection devices. Each of the fuel injectors includes a first solenoid, a first valve, a second solenoid, and a second valve. The fuel injection control device includes a first control section configured to apply current to the first solenoid to drive the first valve and control fuel injection timing under normal injection control. The fuel injector further includes a second control section configured to energize each of the second solenoids using charging energy of an identical charging section under the normal injection control and drive the second valve of each of the fuel injectors to control for changing an injection ratio of the fuel to implement. When the internal pressure of the common rail is reduced under the normal injection control or under an abnormal condition different from the normal injection control, the first control section is configured to implement control to close the first valve, and the second control section is configured to implement control for energizing the second solenoid of at least one targeted fuel injector among the fuel injectors to open the second valve. During a period in which the internal pressure of the common rail is reduced, the second control section is configured to distinguish an energizing period for the second solenoid of the target fuel injector from an energizing period for the second solenoid of the other fuel injector under the normal injection control.

When the internal pressure of the common rail is reduced under the normal injection control or in an abnormal state, the first control section provides control to close the first valve, and the second control section energizes and energizes the second solenoid for at least one targeted fuel injector among the fuel injectors accordingly ready a control for opening the second valve.

During a period for reducing an internal pressure of the common rail, the second control section discriminates an energizing period for the second solenoid of the target fuel injector from an energizing period for the second solenoid of the other fuel injector under the normal injection control. The invention according to claim 5 distinguishes an energizing period for the second solenoid of the target fuel injector from an energizing period for the second solenoid of the other fuel injector under the normal injection control. A charge voltage for the same charge section can be used to energize multiple of the second solenoids. Even in such a case, it is possible to distribute a current load to the charging section and reduce thermal stress. As a result, it is possible to reduce an internal pressure on the common rail without thermally stressing the charging portion as much as possible.

character list

• 1 ein Konfigurationsdiagramm, das ein Kraftstoffinjektionssteuersystem gemäß einer ersten Ausführungsform darstellt;
• 2 eine Schnittansicht, die schematisch eine Kraftstoffinjektionsvorrichtung darstellt;
• 3 ein erläuterndes Diagramm, das einen Kraftstofffluss zum Reduzieren des Innendrucks eines Common-Rails darstellt;
• 4 ein Blockschaltbild, das eine elektrische Konfiguration darstellt;
• 5 ein Schaltbild, das eine Verstärkerschaltung darstellt;
• 6 ein Schaltbild, das eine Ventilansteuereinheit darstellt;
• 7 ein Schaltbild, das eine Pumpenansteuereinheit darstellt;
• 8 Teil 1 eines erläuternden Diagramms, das einen Ablauf einer Injektionssteuerung darstellt;
• 9 ein Diagramm, das Änderungen eines Ventilansteuerstroms darstellt, der an den ersten und den zweiten Elektromagneten angelegt wird;
• 10 ein Ablaufdiagramm, das eine Verarbeitung darstellt, die eine Steuerung zum Reduzieren eines Innendrucks des Common-Rails bereitstellt;
• 11 Teil 2 des erläuternden Diagramms, das einen Ablauf der Injektionssteuerung darstellt;
• 12 ein Diagramm, das Änderungen in einem Ventilansteuerstrom durch Vergleich während einer normalen Operation und einer anormalen Operation darstellt;
• 13 Teil 3 des erläuternden Diagramms, das einen Ablauf der Injektionssteuerung darstellt;
• 14 ein erläuterndes Diagramm, das einen Ablauf einer Injektionssteuerung gemäß einer zweiten Ausführungsform darstellt;
• 15 ein Ablaufdiagramm, das eine Verarbeitung darstellt, die eine Steuerung zum Reduzieren eines Innendrucks des Common-Rails bereitstellt; und
• 16 ein Diagramm, das Änderungen in einem Ventilansteuerstrom durch Vergleich während einer normalen Operation und einer anormalen Operation darstellt.

The object, features and advantages of the present invention are more apparent from the following detailed description with reference to the accompanying drawings. Show it:

• 1 12 is a configuration diagram showing a fuel injection control system according to a first embodiment;
• 2 Fig. 12 is a sectional view schematically showing a fuel injection device;
• 3 Fig. 14 is an explanatory diagram showing a fuel flow for reducing the internal pressure of a common rail;
• 4 12 is a block diagram showing an electrical configuration;
• 5 a circuit diagram showing an amplifier circuit;
• 6 a circuit diagram showing a valve drive unit;
• 7 a circuit diagram showing a pump drive unit;
• 8th Part 1 of an explanatory diagram showing a flow of injection control;
• 9 Fig. 14 is a graph showing changes in a valve drive current applied to the first and second electromagnets;
• 10 12 is a flowchart showing processing that provides control for reducing an internal pressure of the common rail;
• 11 Part 2 of the explanatory diagram showing a flow of the injection control;
• 12 12 is a diagram showing changes in valve drive current by comparison during normal operation and abnormal operation;
• 13 Part 3 of the explanatory diagram showing a flow of the injection control;
• 14 12 is an explanatory diagram showing a flow of injection control according to a second embodiment;
• 15 12 is a flowchart showing processing that provides control for reducing an internal pressure of the common rail; and
• 16 Fig. 14 is a diagram showing changes in valve drive current by comparison during normal operation and abnormal operation.

DETAILED DESCRIPTION

Embodiments of the fuel injection control device will be described with reference to the accompanying drawings. In each embodiment, configurations for performing the same or similar operations are denoted by the same or similar reference numerals, and a description thereof is omitted as necessary.

First embodiment

The configuration of a fuel injection control system 1 is shown in FIG 1 described. The fuel injection control system 1 mainly includes a fuel injection control device (hereinafter referred to as a control device) 2 based on an ECU (electronic (engine) control unit), a feed pump 3, a high-pressure fuel pump 4, a common rail 5, a crank angle sensor 6, fuel injection devices 7 to 10 and an internal combustion engine 11.

The control device 2 individually controls the fuel injection devices 7 to 10 and thereby provides control to cut the fuel combustion chambers of the cylinders #1 to #4 of the internal combustion engine 11. According to the example of the present embodiment, the internal combustion engine 11 uses four cylinders, but is not limited to this, and may use six cylinders. Of four cylinders, two cylinders #1 and #4 are designated as the first bank, and two cylinders #2 and #3 are designated as the second bank.

The feed pump 3 forcibly feeds the fuel stored in a tank 12 to the high-pressure fuel pump 4. The high-pressure fuel pump 4 is, for example, a piston pump. The high-pressure fuel pump 4 pressurizes low-pressure fuel supplied from the feed pump 3 and supplies the fuel as high-pressure fuel to the common rail 5 via the high-pressure fuel pipe 13. The common rail 5 supplies the fuel to the fuel injectors 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 the fuel injectors 7 to 10 via the high-pressure pipe 16 while maintaining the high pressure.

The common rail 5 includes a pressure sensor 14 . The pressure sensor 14 detects fuel pressure stored in the common rail 5 and outputs a detection signal to the control device 2 . The crank angle sensor 6 is combined with a signal rotor 15 and detects the rotation of a crankshaft, not shown, in the internal combustion engine 11. The signal rotor 15 is formed, for example, in a disc shape and rotates integrally with the crankshaft of the internal combustion engine 11. Many protrusions are formed on an outer periphery of the signal rotor 15 . The crank angle sensor 6 outputs a crank angle signal corresponding to the approach and departure of the protrusions on the signal rotor 15 .

The control device 2 is configured to calculate an engine speed by receiving the crank angle signal from the crank angle sensor 6 . The controller 2 provides control for changing the torque for rotating the crankshaft according to a change in the sensor signal S. The controller 2 provides control for injecting the fuel by the fuel injectors 7 to 10 based on various sensor signals S including the crank angle signal.

Basic Configuration and Operations of Fuel Injectors 7 to 10

A basic configuration and operation of the fuel injection devices 7 to 10 will be described. The fuel injection devices 7 to 10 inject the fuel into the cylinders of the internal combustion engine 11 and are also referred to as injectors or fuel injection valves.

The fuel injectors 7 to 10 include built-in pressure sensors 7a to 10a, respectively. The fuel injection devices 7 to 10 are structured in the same way. Therefore, in the following description, the structure of the fuel injector 7 is explained, and a description of the structure of the fuel injectors 8 to 10 is omitted.

As in 2 is shown, the fuel injection device 7 mainly includes first to fourth elements 21 to 24, a nozzle needle 25, a spring 26 for the nozzle needle 25, an oil pressure driven valve 27, a spring 28 for the oil pressure driven valve 27, 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.

A first high-pressure fuel passage 35 , a low-pressure chamber 36 and a low-pressure path 37 are arranged in the first element 21 . In the configuration where the first to third members 21 to 23 are provided, the first high pressure fuel passage 35 penetrates through the first to third members 21 to 23 . The common rail 5 delivers the high-pressure fuel through the high-pressure line 16.

When the first valve 29 opens, the low-pressure chamber 36 provided in the first member 21 communicates with a third path 39 from an opening on the second member 22 side. When the first valve 29 closes, the low-pressure chamber 36 is isolated from the third path 39 . When the second valve 30 opens, the low-pressure chamber 36 is connected to a second path 41 from an opening on the second member 22 side. When the second valve 30 closes, the low-pressure chamber 36 is isolated from the second path 41 .

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 . The low-pressure path 37 is connected to the low-pressure chamber 36 . The low-pressure path 37 is provided with an in 1 illustrated low-pressure line 38 connected. 1. The low-pressure fuel in the low-pressure chamber 36 flows from the low-pressure chamber 36, passes through the nozzle the pressure path 37 and the low pressure line 38 and returns to the fuel tank 12.

The low pressure chamber 36 of the first member 21 accommodates the first valve 29, the second valve 30, the first solenoid 31, the second solenoid 32, the first spring 33 and the second spring 34 inside.

Normally, the first spring 33 is placed to exert a force in a direction that allows the first valve 29 to approach the third path 39 . In this way, the first valve 29 closes to separate the low-pressure chamber 36 from the third path 39 . The second spring 34 is arranged to exert a force in a direction that allows the second valve 30 to approach the second path 41 . In this way, the second valve 30 closes to isolate the low-pressure chamber 36 from the second path 41 .

When energized, the first solenoid 31 generates an electromagnetic force, responds to the force exerted by the first spring 33 and allows the first valve 29 to deviate from the second member 22 . When energized, the first solenoid 31 is configured to open the first valve 29 . The first valve 29, when open, allows communication between the low pressure chamber 36 and the third path 39.

When energized, the second solenoid 32 generates an electromagnetic force, responds to the force exerted by the second spring 34, and allows the second valve 30 to deviate from the second member 22. When energized, the second solenoid 32 is configured to open the second valve 30 . The second valve 30, when open, allows communication between the low pressure chamber 36 and the second path 41.

The second member 22 includes the third path 39, an intermediate chamber 40, the second path 41, and a second high-pressure fuel passage 35a branched from the first high-pressure fuel passage 35. As shown in FIG. The high-pressure fuel is supplied to branch from the first high-pressure fuel passage 35 to the second high-pressure fuel passage 35a. The second high-pressure fuel passage 35a includes a third restriction 35aa connected to an annular chamber 42 . The third restriction 35aa restricts a flow rate of the high-pressure fuel flowing through the second high-pressure fuel passage 35a. The structure of the second high-pressure fuel passage 35a itself may be configured as the third restriction 35aa by including a plurality of third restrictions 35aa or reducing a passage area of the second high-pressure fuel passage 35a.

The second path 41 includes a second restriction 41a and connects the low pressure chamber 36 and a first control chamber 43 without using the interior of the oil pressure driven valve 27 therebetween. The structure of the second path 41 itself can be configured as the second constriction 41a by including a plurality of second constrictions 41a or by reducing a channel area of the second path 41 .

The annular chamber 42 is annularly configured and communicates with the first control chamber 43 through an opening on the third member 23 side. The third member 23 includes the first control chamber 43. The first control chamber 43 is disposed in contact with the second member 22 and partially includes an opening on the second member 22 side. The perimeter of the opening is between the second member 22 and the third member 23 sealed. The first control chamber 43 is connected to a communication path 44 . The communication path 44 connects the first control chamber 43 to a second control chamber 49. The communication path 44 includes a fourth restriction 44a. The fourth restriction 44a restricts a flow rate of fuel flowing through the communication path 44 . The connection path 44 may include a plurality of fourth restrictions 44a. The structure of the connection path 44 itself can include the function of the fourth constriction 44a by reducing a channel area of the connection path 44 .

The oil pressure driven valve 27 is placed in the first control chamber 43 . The oil pressure driven valve 27 has a cylindrical configuration. The cylindrical oil pressure driven valve 27 allows a first path 45 to pierce toward a central axis line. The first path 45 includes a first constriction 45a. The first restriction 45a restricts a flow rate of fuel flowing through the first path 45 . The first path 45 may include the function of the first restriction 45a by including multiple first restrictions 45a or by reducing a channel area of the first path 45 .

The spring 28 is located in the first control chamber 43 and exerts a force in a direction that allows the oil pressure driven valve 27 to approach the second member 22 . When the oil pressure driven valve 27 contacts the second member 22, the intermediate chamber 40 communicates with the first control chamber 43 via the first path 45 and the first restriction 45a. However, the oil pressure driven valve 27 closes the opening on the third member 23 side of the annular chamber 42.

As in 3 For example, as shown, the oil pressure driven valve 27 is separate from the second member 22. In this case, the intermediate chamber 40 communicates with the first control chamber 43 without the first path 45 in between to use. The annular chamber 42 is also connected to the first control chamber 43 . As in 2 and 3 As shown, the second path 41 is connected to the first control chamber 43 without using the oil pressure driven valve 27 therebetween. The second path 41 directly connects the low pressure chamber 36 and the first control chamber 43 regardless of positions or stroke states of the oil pressure driven valve 27 .

As in 2 As shown, the fourth element 24 includes a high pressure chamber 46, an injection hole 47, a cylinder 48 and the second control chamber 49. The high pressure fuel is supplied to the high pressure chamber 46 through the first high pressure fuel passage 35. As shown in FIG. The nozzle needle 25 is arranged in the fourth element 24 . The nozzle needle 25 is configured to have a conical tip and a cylindrical base. The high-pressure chamber 46 is placed to cover the nozzle needle 25 side. The cylinder 48 supports the nozzle needle 25 so that the nozzle needle 25 is configured to be in 2 slides back and forth in the up-down direction. The second control chamber 49 is placed at the rear of the nozzle needle 25 . The second control chamber 49 is connected to the first control chamber 43 via the communication path 44 .

The spring 26 is arranged in the second control chamber 49 and exerts a force in a direction that presses the nozzle needle 25 against the injection hole 47 . The first control chamber 43 and the second control chamber 49 configure a control chamber. The injection hole 47 is connected to the cylinder of the internal combustion engine 11 .

When the pressure in 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 separated from each other. Alternatively, the nozzle needle 25 moves in a direction to close the injection hole 47 . The pressure in the second control chamber 49 may be lower than a predetermined pressure. In such a case, the nozzle needle 25 moves to the third element 23, namely to the top of the drawing. In this case, the high-pressure fuel is injected from the high-pressure chamber 46 through the injection hole 47 . Therefore, it is possible to connect or disconnect the high-pressure chamber 46 to or from the cylinder within the internal combustion engine 11 based on the pressure within the first control chamber 43 and the second control chamber 49.

Pressure changes in the chambers of fuel injectors 7 to 10

The fuel injection control system 1 operates in different modes. Based on the modes, the control device 2 provides control to inject the fuel from the injection hole 47 of the fuel injectors 7 to 10 or to discharge the fuel into the fuel tank 12 through the fuel injectors 7 to 10 . This makes it possible to reduce the internal pressure of the common rail 5 . The following description explains pressure changes in the chambers inside the fuel injectors 7 to 10 in response to the operation of opening and closing the first valve 29 and the second valve 30 in each mode.

It is assumed that the first spring 33 and the second spring 34 apply a force to close the first valve 29 and the second valve 30 . When the first valve 29 is closed, the third path 39 is isolated from the low-pressure chamber 36 . When the second valve 30 is closed, the second path 41 is isolated from the low-pressure chamber 36 . This initial condition seals the second control chamber 49, the first control chamber 43, the intermediate chamber 40, the third path 39 and the second path 41 internally. Internal fuel pressures are kept high and balanced. Therefore, the injection hole 47 is closed. The spring 28 exerts a force on the oil pressure driven valve 27 which then comes into contact with the second element 22 .

Low injection ratio mode

The low injection ratio mode relatively slowly injects the fuel into the engine 11 through the injection hole 47. The following description explains changes in pressure states in the chambers inside the fuel injectors 7 to 10 in the low injection ratio mode. In the low injection ratio mode, the controller 2 opens the first valve 29 from the initial state while closing the second valve 30, and then closes the first valve 29.

When the first valve 29 opens, the third path 39 is connected to the low-pressure chamber 36 . The third path 39 connects the low pressure chamber 36, the intermediate chamber 40 and the first control chamber 43. The first control chamber 43 and the intermediate chamber 40 switch to low pressure. The intermediate chamber 40 goes to low pressure similar to that of the low pressure chamber 36.

The fuel stored in the first control chamber 43 flows through the first path 45 to the intermediate chamber 40. However, the first restriction 45a limits the flow rate of fuel through the first restriction 45a. The first path 45 causes a pressure difference before and after the fuel passes through the first restriction 45a. The first control chamber 43 remains in an intermediate pressure state.

The fuel pressure in the first control chamber 43 pulls the oil pressure driven valve 27 toward the intermediate chamber 40 of the second member 22. The oil pressure driven valve 27 closes the opening in the annular chamber 42 on the third member 23 side, thereby closing the separation between the second high-pressure fuel passage 35a and of the first control chamber 43 is maintained.

The pressure of the first control chamber 43 changes to the intermediate pressure state. The pressure of the second control chamber 49 also changes to the intermediate pressure state. Then, the high-pressure fuel acts on the nozzle needle 25 through the first high-pressure fuel passage 35 and pushes the nozzle needle 25 along the cylinder 48 toward the second control chamber 49. The nozzle needle 25 is thereby opened. The high-pressure fuel is injected from the injection hole 47 . The fuel passage through the first restriction 45a is restricted to be relatively narrow, thereby reducing the velocity of the first control chamber 43 to reach the intermediate pressure condition. As a result, the nozzle needle 25 opens relatively slowly, thereby relatively reducing an injection ratio, namely, a change in fuel injection amount compared with the lapse of time.

When the first valve 29 is closed, the third path 39, the intermediate chamber 40, the second path 41 and the first control chamber 43 are sealed. The fuel in the first control chamber 43 also flows into the intermediate chamber 40 and the third path 39 through the first restriction 45a. The fuel in the second high pressure fuel passage 35a pushes the oil pressure driven valve 27 through the annular chamber 42 to respond to the force exerted by the spring 28.

Consequently, the lift amount of the oil pressure driven valve 27 decreases. The high-pressure fuel flows into the first control chamber 43 and the second control chamber 49 through the annular chamber 42. As a result, the first control chamber 43 and the second control chamber 49 change to high pressure. When the internal pressure of the first control chamber 43 and the second control chamber 49 changes to a pressure approximately as high as the pressure of the first high-pressure fuel passage 35, the force exerted by the spring 28 acts and allows the oil pressure-operated valve 27 to come into contact with the second member 22 . As a result, the oil pressure driven valve 27 separates the annular chamber 42 from the first control chamber 43. The above initial state is resumed.

High injection ratio mode

A high injection ratio mode injects the fuel from the injection hole 47 at high speed. The following description explains changes in the pressure states in the chambers inside the fuel injectors 7 to 10 in the high injection ratio mode. In the high injection ratio mode, the controller 2 provides control to open the first valve 29 and the second valve 30 almost simultaneously from the initial state.

When the first valve 29 and the second valve 30 open almost simultaneously, the third path 39 communicates with the low-pressure chamber 36 . The second path 41 also communicates with the low-pressure chamber 36 . Therefore, the low-pressure chamber 36, the intermediate chamber 40 and the first control chamber 43 are connected to each other via the third path 39 and the second path 41. The first control chamber 43 and the intermediate chamber 40 change to low pressure.

The intermediate chamber 40 changes to low pressure similar to the low-pressure chamber 36 . However, the intermediate chamber 40 is configured to transition to a low pressure more quickly than when only the first valve 29 opens as described above. The fuel stored in the first control chamber 43 flows toward the intermediate chamber 40 through the first path 45. However, the first restriction 45a limits the flow rate of the fuel. The first path 45 causes a pressure difference before and after the fuel passes through the first restriction 45a.

The fuel in the first control chamber 43 also flows into the low-pressure chamber 36 through the second path 41. The second restriction 41a restricts the flow rate of the fuel flowing through the second restriction 41a. The second path 41 causes a pressure difference before and after the fuel passes through the second restriction 41a. The first control chamber 43 remains in the intermediate pressure state.

The fuel pressure in the first control chamber 43 pulls the oil pressure driven valve 27 toward the intermediate chamber 40 of the second member 22. The oil pressure driven valve 27 closes the opening in the annular chamber 42 on the third member's side Element 23, whereby the separation between the second high-pressure fuel passage 35a and the first control chamber 43 is maintained.

When the first control chamber 43 enters the intermediate pressure state, the pressure of the second control chamber 49 also changes to the intermediate pressure state. The first control chamber 43 and the second control chamber 49 enter the intermediate pressure state. In this state, the nozzle needle 25 slides toward the second control chamber 49 along the cylinder 48 when the high-pressure fuel acts on the nozzle needle 25 via the first high-pressure fuel passage 35 as above. The nozzle needle 25 thereby opens to inject the high-pressure fuel from the injection hole 47 . The fuel passage through the first restriction 45a and the second restriction 41a is restricted to be wider than the above-mentioned low injection ratio mode. The first control chamber 43 reaches the intermediate pressure state at a higher speed. As a result, the nozzle needle 25 opens relatively quickly and relatively increases an injection ratio, namely, a change in fuel injection amount compared with the lapse of time.

When the second valve 30 is closed thereafter, the internal oil pressure does not normally vary in the chambers including the first control chamber 43. When the first valve 29 is closed thereafter, the fuel in the first control chamber 43 flows through the first restriction 45a into the intermediate chamber 40 and the third path 39. Then, the third path 39, the intermediate chamber 40, the second path 41 and the first control chamber 43 are sealed. The intermediate chamber 40 and the first control chamber 43 enter the intermediate pressure state.

A pressure difference is created between the annular chamber 42 and the first control chamber 43 . The fuel in the second high pressure fuel passage 35a pushes the oil pressure driven valve 27 through the annular chamber 42 to respond to the force exerted by the spring 28. Consequently, the lift amount of the oil pressure driven valve 27 decreases. The high-pressure fuel flows into the first control chamber 43 and the second control chamber 49 through the annular chamber 42. As a result, the first control chamber 43 and the second control chamber 49 change to high pressure. When the internal pressure of the first control chamber 43 and the second control chamber 49 changes to a pressure approximately as high as the pressure of the first high-pressure fuel passage 35, the force exerted by the spring 28 acts and causes the oil pressure-operated valve 27 to come into contact with the second member 22. As a result, the oil pressure driven valve 27 separates the annular chamber 42 from the first control chamber 43. The above initial state is resumed.

Different lifting speeds of the nozzle needle 25 depending on the opening and closing states of the second valve 30

When the first valve 29 and the second valve 30 open almost simultaneously, the internal pressure of the first control chamber 43 reduces more rapidly than in the case of opening only the first valve 29. When the first valve 29 and the second valve 30 open almost simultaneously, rises the nozzle needle 25 faster than in the case of opening only the first valve 29. When the first valve 29 and the second valve 30 open at the same time, an injection ratio can be higher than in the case of opening only the first valve 29.

Boot injection mode

The following description explains pressure changes in the chambers within the fuel injection device 7 in the boot injection mode or boot injection mode. In the boat injection mode, the fuel injectors 7 to 10 inject the fuel from the injection hole 47 by increasing the injection ratio stepwise. In the boot injection mode, the controller 2 opens the first valve 29 from the above initial state and then opens the second valve 30.

When the first valve 29 opens, the third path 39 is connected to the low-pressure chamber 36 . Therefore, the low-pressure chamber 36, the intermediate chamber 40 and the first control chamber 43 are connected to each other via the third path 39. FIG. The first control chamber 43 and the intermediate chamber 40 change to low pressure. The intermediate chamber 40 changes to a low pressure similar to that of the low pressure chamber 36. The fuel stored in the first control chamber 43 flows towards the intermediate chamber 40 through the first path 45. However, the first restriction 45a limits the flow rate of the fuel passing through the first restriction 45a flows. The first path 45 causes a pressure difference before and after the fuel passes through the first restriction 45a. The first control chamber 43 remains in the intermediate pressure state. The fuel pressure in the first control chamber 43 pulls the oil pressure driven valve 27 towards the intermediate chamber 40 of the second member 22. The oil pressure driven valve 27 closes the opening towards the third member 23 of the annular chamber 42, thereby separating the second high pressure fuel passage 35a and the first Control chamber 43 is maintained.

As above, the high-pressure fuel acts on the nozzle needle 25 through the first high-pressure fuel passage 35 to push the nozzle needle 25 along the cylinder 48 toward the second control chamber 49 . The injection hole 47 is thereby opened to inject the high-pressure fuel from the injection hole 47 . The fuel passage through the first restriction 45a is restricted to be relatively narrow, thereby reducing the speed of the first control chamber 43 to transition to low pressure. As a result, the nozzle needle 25 opens relatively slowly, thereby relatively reducing an injection ratio, namely, a change in fuel injection amount compared to the timing for the initial period of the boot injection mode. When the second valve 30 opens thereafter, the fuel in the first control chamber 43 also flows through the second path 41 into the low-pressure chamber 36. The second restriction 41a then limits the flow rate of the fuel through the second restriction 41a. The second path 41 causes a pressure difference before and after the fuel passes through the second restriction 41a.

The fuel path through the first restriction 45a and the second restriction 41a is wider than the same available for the initial period of the boot injection mode, thereby increasing the speed to reduce the pressure of the first control chamber 43 and reach the intermediate pressure state. As a result, the nozzle needle 25 opens relatively quickly and relatively increases an injection ratio, namely, a change in fuel injection amount compared with the lapse of time.

When the second valve 30 is closed thereafter, the internal oil pressure does not normally change in the chambers including the first control chamber 43. When the first valve 29 is closed thereafter, the fuel in the first control chamber 43 flows through the first restriction 45a into the intermediate chamber 40 and the third path 39. Then the third path 39, the intermediate chamber 40, the second path 41 and the first control chamber 43 are sealed. The intermediate chamber 40 and the first control chamber 43 enter the intermediate pressure state.

A pressure difference is created between the annular chamber 42 and the first control chamber 43 . The fuel in the second high pressure fuel passage 35a pushes the oil pressure driven valve 27 through the annular chamber 42 to respond to the force exerted by the spring 28. Consequently, the lift amount of the oil pressure driven valve 27 decreases. The high-pressure fuel flows into the first control chamber 43 and the second control chamber 49 through the annular chamber 42. As a result, the first control chamber 43 and the second control chamber 49 change to high pressure. When the internal pressure of the first control chamber 43 and the second control chamber 49 changes to about the same as the pressure of the first high-pressure fuel passage 35, the force exerted by the spring 28 acts and lets the oil-pressure-operated valve 27 with the second element 22 in contact. As a result, the oil pressure driven valve 27 separates the annular chamber 42 from the first control chamber 43. The above initial state is resumed.

Rail pressure reduction mode and full pressure reduction mode

The rail pressure reduction mode and the full pressure reduction mode are described with reference to FIG 3 described. The rail pressure reduction mode and the full pressure reduction mode are provided to reduce the internal pressure of the common rail 5 . In the rail pressure reduction mode, the control device 2 provides control to allow the second solenoid 32 to open the second valve 30 while providing control to allow the first solenoid 31 to keep the first valve 29 closed from the initial state .

In the initial state, as above, the spring 28 exerts a force on the oil pressure driven valve 27 which then comes into contact with the second member 22. When the second valve 30 opens in this state, the fuel stored in the first control chamber 43 is discharged into the low-pressure chamber 36 via the second path 41, whereby the internal pressure of the first control chamber 43 is reduced.

The fuel stored in the second high pressure fuel passage 35a pushes the oil pressure driven valve 27 through the annular chamber 42. The oil pressure driven valve 27 exits the second member 22 to reduce the lift amount. Then the first control chamber 43 is connected to the intermediate chamber 40 . The pressure of the intermediate chamber 40 and the pressure of the first control chamber 43 change to the same level. The oil pressure driven valve 27 is not drawn into the intermediate chamber 40 due to the fuel pressure of the second high pressure fuel passage 35a. Therefore, the fuel flows from the common rail 5 through the first high-pressure fuel passage 35, the second high-pressure fuel passage 35a, the first control chamber 43 and the second path 41 into the low-pressure chamber 36. The fuel is fed from the low-pressure chamber 36 via the low-pressure line 38 into the fuel tank 12 delivered. See the one indicated by arrows in 3 specified fuel flow.

The fuel flows into the first control chamber 43 via the third restriction 35aa of the second high-pressure fuel passage 35a. The flow rate of this fuel is configured to be higher than the flow rate of the fuel flowing into the low-pressure chamber 36 via the second restriction 41a of the second path 41 flows. Therefore, the amount of fuel discharged from the first control chamber 43 is larger than the amount of fuel flowing into the first control chamber 43 from the second high-pressure fuel passage 35a.

As a result, the first control chamber 43 and the second control chamber 49 do not reduce the fuel pressure. The nozzle needle 25 does not slide along the cylinder 48. The nozzle needle 25 is configured to thereby keep the high-pressure chamber 46 separated from the injection hole 47. As a result, it is possible to inject the fuel from the low-pressure chamber 36 without injecting the fuel from the injection hole 47 into the engine 11 . The internal pressure of the common rail 5 can be reduced.

As above, the rail pressure reduction mode can reduce the internal pressure of the common rail 5 by using at least one fuel injector (like the fuel injector 7). In addition, the full pressure reduction mode performs the processing in the rail pressure reduction mode using all the fuel injectors 7 to 10 . The full pressure reduction mode can quickly reduce the internal pressure of the common rail 5 using all the fuel injectors 7 to 10 .

Electrical configuration of the control device 2

The following description explains control circuits of the fuel injection devices 7 to 10. 4 shows schematically an electrical configuration of the control device 2.

The power supply voltage VB is supplied from a battery for the control device 2 to operate. The example below uses the supply voltage VB set to 12V, but can be set to 24V and change as required. The control device 2 includes a microcomputer 51, a first control IC 52, a second control IC 53, a first amplifier circuit 54, a second amplifier circuit 55, first valve drive units 56 and 57, second valve drive units 58 and 59 and the pump drive unit 60. The first Control IC 52 is comparable to a first control section. The second control IC 53 is comparable to a second control section.

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

The microcomputer 51 includes a CPU and an internal memory such as RAM and ROM (not shown). The microcomputer 51 mainly provides various controls by executing programs stored in the internal memory. The microcomputer 51 outputs an injection signal to the first control IC 52 and the second control IC 53 based on an injection start instruction or an injection stop instruction.

The microcomputer 51 is configured to communicate with the first control IC 52 and the second control IC 53 using a serial communication line. The microcomputer 51 is configured to change various setting values assigned to each memory of the first control IC 52 and the second control IC 53 . At this time, the microcomputer centrally controls the first control IC 52 and the second control IC 53. As will be described in detail later, the set value includes values for peak current Ip and Ip2 as maximum currents, values for absorption currents Ipa and Ipa2, values for constant currents Ipb and Ipb2 and continued periods of excitation for these. The microcomputer 51 uses a dedicated line to output a pump control signal to the first control IC 52 . The pump control signal controls the high-pressure fuel pump 4.

The first control IC 52 and the second control IC 53 are integrated circuit devices available as an ASIC, for example. The first control IC 52 and the second control IC 53 include a logic circuit and a CPU as control bases and memories such as RAM, ROM, and EEPROM, and provide various controls based on the hardware and the software.

The first control IC 52 provides control for driving the first booster circuit 54, the first valve drive units 56 and 57, and of the pump driver 60. The first booster circuit 54 boosts the power supply voltage VB based on a boost control signal input from the first control IC 52. FIG. The first booster circuit 54 supplies a first booster voltage Vboost1 higher than the power supply voltage VB to the first valve drive units 56 and 57 and the pump drive unit 60.

5 12 shows an exemplary configuration of the first booster circuit 54. An inductor 71, a drain-source path of an n-channel MOSFET 72, and a resistor 73 are connected in series between a supply terminal of the power supply voltage VB and ground. A diode 74 is connected from a common connection point between the coil 71 and the drain of the MOSFET 72 to an output node of the first forward-biased boosting voltage Vboost1. A charging capacitor 75 is connected between the output node and the source of MOSFET 72 . The first control IC 52 provides control for turning on or off the MOSFET 72 to supply the coil 71 with a current. At the same time, the energy stored in the coil 71 can be stored in the charging capacitor 75 gradually. The charging capacitor 75 is configured to thereby charge the first boosting voltage Vboost1 higher than the power supply voltage VB.

6 12 shows a circuit configuration of the first valve drive unit 56. The first valve drive unit 56 energizes or de-energizes the first solenoid 31 connected to output ports 2a to 2c of the control device 2 to drive the first valve 29 of the fuel injectors 7 and 10 corresponding to cylinders #1 and #4 of Fig head for the first bank. The first control IC 52 thereby controls the fuel injection timing using the first valve driver 56 to apply the current to the first solenoid 31 .

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

The first boosting voltage Vboost1 is charged into the charging capacitor 75 of the first booster circuit 54 and input to the drain of the MOS transistor which is an input terminal of the discharge switch 81 . The discharge switch 81 uses the input terminal to be supplied with the first boosting voltage Vboost1 corresponding to a control signal supplied to a control terminal of the discharge switch 81 from the first control IC 52 . The discharge switch 81 is configured to use the output terminal to supply a first boosting voltage Vboost1 to a positive output terminal 2a of the control device 2 .

The drain-source path of a MOS transistor configuring the constant current switch 82 and the anode-cathode path of the diode 87 are connected in series between an input node of the power supply voltage VB and the positive output terminal 2a of the controller 2 . The diode 88 is reversely connected between the positive output terminal 2a of the controller 2 and ground. The diodes 87 and 88 prevent energization from the positive output terminal 2a to the supply terminal of the power supply voltage VB and energization from the positive output terminal 2a to the ground, respectively.

The first solenoid 31 for driving the first valve 29 of the fuel injection device 7 is connected between the positive output port 2a and a first negative port 2b of the control device 2 . When energized, the first solenoid 31 opens the first valve 29 of the fuel injector 7. When de-energized, the first solenoid 31 allows the first valve 29 to be closed due to the force exerted by the first spring 33.

A diode 89 is forward-connected between the first negative terminal 2b of the controller 2 and an output node of the first boosting voltage Vboost1 of the first booster circuit 54 . When an injection stop instruction is accepted, the diode 89 recharges the charged energy to the charging capacitor 75 of the first booster circuit 54 based on a current flowing through the first solenoid 31 .

The first solenoid 31 is connected between the positive output port 2a and a second negative port 2c of the control device 2 to drive the first valve 29 of the fuel injection device 10 . When energized, the first solenoid 31 opens the first valve 29 of the fuel injection device 10. When de-energized, the first solenoid 31 closes the first valve 29.

A diode 90 is forward-connected between the second negative terminal 2c of the controller 2 and the output node of the first boosting voltage Vboost1 of the first booster circuit 54 . When the first control IC 52 receives the injection stop instruction as Injec tion signal from the microcomputer 51 is accepted, the diode 90 charges the stored energy back to the charging capacitor 75 of the first booster circuit 54 based on a current flowing through the first solenoid 31 .

The drain-source path of a MOS transistor configuring the selection switch 83 and the current-detecting resistor 85 is connected in series between the first negative terminal 2b of the control device 2 and ground. The drain-source path of a MOS transistor configuring the selection switch 84 and the current-sensing resistor 86 is connected in series between the second negative terminal 2c of the control device 2 and ground.

The selection switches 83 and 84 select the fuel injectors 7 and 10 that inject the fuel. While the selector switch 83 is on, the current detection resistor 85 detects a current flowing through the first solenoid 31 of the fuel injector 7 based on a voltage. The detection value is input to the first control IC 52 . While the selector switch 84 is on, the current detection resistor 86 detects a current flowing through the first solenoid 31 of the fuel injector 10 based on a voltage. The detection value is input to the first control IC 52 .

The first control IC 52 provides control for turning on and off the discharge switch 81, the constant current switch 82 and the selection switches 83 and 84 based on setting values and injection signals supplied from the microcomputer 51 and the current detected by the current detection resistor 85 becomes. Since the first valve driver 56 is configured as above, the first control IC 52 is configured to use the first valve driver 56 to control supplying or not supplying the current to the first solenoid 31 and opening and closing the first valve 29 of the fuel injection devices 7 and 10 to implement.

The first valve driver 57 energizes or de-energizes the first solenoid 31 connected to the output ports 2a to 2c of the controller 2 to drive the first valve 29 of the fuel injectors 8 and 9 corresponding to cylinders #2 and #3 of the second bank. The first control IC 52 thereby controls the fuel injection timing using the first valve driver 57 to energize the first solenoid 31. The first valve driver 57 has the same circuit configuration as the first valve driver 56 and description is omitted for simplicity.

The pump control unit 60, which is 7 is illustrated, the high-pressure fuel pump 4 controls. The pump drive unit 60 drives the high-pressure fuel pump 4 by energizing or de-energizing a solenoid 61 for driving the high-pressure fuel pump 4 connected to the output ports 2d and 2e of the controller 2 .

The pump drive unit 60 mainly includes 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 and 97 as shown in the drawing. The pump driver 60 includes a pump selection switch 93. The other configurations of the pump driver 60 are the same as those of the first valve driver 56, and a description of the wiring is omitted for simplicity. The first control IC 52 is configured to turn on and off a current supplied to the solenoid 61 for driving the high pressure fuel pump 4 using the pump drive unit 60 and is configured to implement control for driving the high pressure fuel pump 4 .

For further description becomes 4 returned. The second control IC 53 provides control for driving 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 a boost control signal from the second control IC 53 and supplies a second boosting 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 that of the first amplifier circuit 54. Therefore, the description of the circuit configuration is omitted for the sake of simplicity. The value of the first boosting voltage Vboost1 for the first booster circuit 54 may or may not be equal to the value of the second boosting voltage Vboost2 for the second booster circuit 55 . The charging capacitor 75 of the second booster circuit 55 is comparable to a "charging section" according to the present invention.

The second valve driver 58 energizes or de-energizes the second solenoid 32 connected to the output port of the controller 2 to drive the second valve 30 of the fuel injectors 7 and 10 corresponding to the cylinders #1 and #4 of the first bank. The second control IC 53 provides control for changing fuel injection ratios using the second valve drive unit 58 for applying a current to the second solenoid 32 for the second valve 30 of the fuel injectors 7 and 10 corresponding to cylinders #1 and #4 of the first bank. 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 a description is omitted for the sake of simplicity.

The second valve driver 59 energizes or de-energizes the second solenoid 32 connected to the output port of the controller 2 to drive the second valves 30 for the fuel injectors 8 and 9 corresponding to the second bank cylinders #2 and #3. The second control IC 53 provides control for changing fuel injection ratios using the second valve driver 59 to apply current to the second solenoid 32 for the second valves 30 of the fuel injectors 8 and 9 corresponding to cylinders #2 and #3 of the second bank. 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 is omitted for the sake of simplicity.

Drive control processing for the high-pressure fuel pump 4

The following description explains basic pump drive processing of the high-pressure fuel pump 4 with reference to FIG 8th . The pressure of the fuel stored in the common rail 5 reduces when the fuel injectors 7 to 10 inject the fuel from the injection hole 47 . The microcomputer 51 of the control device 2 outputs a boost command as a pressure adjustment command signal to the first control IC 52 when the pressure sensor 14 detects that the fuel pressure drops to a pressure lower limit or lower. The first control IC 52 provides control for driving the high-pressure fuel pump 4 using the pump drive unit 60 and thereby increases the internal pressure of the common rail 5. As in FIG 8th 1, the drive control via the high-pressure fuel pump 4 is performed once per crank angle 180° CA. Therefore, it is possible to adjust the internal pressure of the common rail 5 within a predetermined range.

Circuit operations of the pump drive unit 60 are described with reference to FIG 7 described. When the first control IC 52 accepts the boost command as a pressure adjustment command signal, the first control IC 52 provides control to turn on the pump select switch 93 and the pump drive switch 91 . The first control IC 52 applies a first boosting voltage Vboost1 to the solenoid 61 to drive the high-pressure fuel pump 4 . The first control IC 52 provides control for turning off the pump drive switch 91 when a current detected by the current detection resistor 94 reaches a peak limit value. The drive current for the high-pressure fuel pump 4 then decreases. When the current detected by the current detection resistor 94 reaches a constant current range lower than the peak limit value, the first control IC 52 provides control to turn on or off the pump constant current switch 92 to maintain the driving current for the high pressure fuel pump 4 within a specified range . The operation of the high-pressure fuel pump 4 is thereby maintained. When the first control IC 52 accepts a boost stop command as a pressure adjustment command signal from the microcomputer 51, the first control IC 52 provides control to turn off all the switches 91 to 93 to stop the operation of the high-pressure fuel pump 4.

Basic injection control processing

Basic injection control processing will be described below. The internal combustion engine 11 using four cylinders and four cycles performs single injection or multi-stage injection such as three injections and five injections within a range of crank angle 180° CA according to a crank angle signal before and after top dead center (TDC). For example, five injections are each referred to as pre-injection, pre-injection, main injection, post-injection, and post-injection. For example, three injections will skip the pre- and post-injection.

The control device 2 provides control for injecting the fuel from the injection hole 47 of the fuel injection devices 7 to 10 into the cylinder of the internal combustion engine 11 . In this case, the microcomputer 51 outputs an injection start signal corresponding to each of the fuel injectors 7 to 10 to the first control IC 52 and the second control IC 53 .

The following description explains an example in which the microcomputer 51 outputs injection start signals corresponding to injections M and M2 from the fuel injector 7 corresponding to 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 providing control to connect or close the first orifice 45a separate. In parallel with the processing of the first control IC 52, the second control IC 53 uses the second valve driver 58 to energize the second solenoid 32 and drive the second valve 30, thereby providing control for connecting or disconnecting the second orifice 41a and controls the fuel injection ratio.

9 FIG. 12 shows changes in a valve drive current flowing through the first solenoid 31 and the second solenoid 32. FIG. The first control IC 52 provides control for turning on the selection switch 83 and at the same time provides control for turning on the discharging switch 81 and the constant current switch 82.

The discharge switch 81, the constant current switch 82 and the selection switch 83 turn on to apply the first boosting voltage Vboost1 for the charging capacitor 75 of the first booster circuit 54 to the first solenoid 31. FIG. Therefore, a valve drive current increases. The valve drive current then reaches the peak current Ip set for the microcomputer 51. Then, the first control IC 52 detects the peak current Ip based on the voltage detected by the current detection resistor 85 and provides control to turn off the discharge switch 81 . Then the valve drive current decreases and reaches the pick-up current Ipa.

The first control IC 52 detects that the valve drive current reaches the absorbing current Ipa. Then, the first control IC 52 holds the absorbing current Ipa by providing control to turn the constant current switch 82 on or off. The absorption current Ipa is set to be lower than the peak current Ip and is generated using the power supply voltage VB without using the boosting voltage Vboost1 charged in the charging capacitor 75 of the first booster circuit 54 .

The first control IC 52 thereafter terminates the instruction period Tp1 set by the microcomputer 51 for the peak current Ip. Then, the first control IC 52 provides control for turning on or off the constant current switch 82 to reduce the valve drive current to be lower than the absorbing current Ipa and to keep the predetermined constant current Ipb greater than zero. The predetermined constant current Ipb is configured to be lower than the absorption current Ipa and is generated using the power supply voltage VB without using the boosting voltage Vboost1 charged in the charging capacitor 75 of the first booster circuit 54 . The microcomputer 51 then outputs an injection stop signal. The first control IC 52 receives the injection stop signal from the microcomputer 51, provides control to turn off the constant current switch 82, and thereby reduces the valve drive current.

The second control IC 53 accepts an injection start signal and then provides control to turn on or off the switches 81 to 83. As shown in FIG 9 As can be seen, showing current waveforms during injection M2, the second control IC 53 provides control to set the valve drive current to the peak current Ip2, then to a pickup current Ipa2 lower than the peak current Ip2, and then to the predetermined constant current Adjust Ipb2, which is lower than intake current Ipa2. The control processing performed by the second control IC 53 to turn on or off the switches 81 to 83 has contents similar to the above-mentioned control processing performed by the first control IC 52 to turn on or off the switches 81 to 83. and the description is omitted for the sake of simplicity.

Based on the control to turn on or off the discharge switch 81, the second control IC 53 generates the peak current Ip2 using the charged energy charged in the charging capacitor 75 of the second booster circuit 55 and the second boosting voltage Vboost2. The second control IC 53 generates a pickup current Ipa2 and a constant current Ipb2 by providing control for turning the constant current switch 82 and the selection switch 83 on or off, while providing control for turning the discharge switch 81 off. Therefore, the absorption current Ipa2 and the constant current Ipb2 are generated using the power supply voltage VB without using the charged energy charged in the charging capacitor 75 of the second booster circuit 55 and the second boosting voltage Vboost2.

The microcomputer 51 sets the current setting values (peak current Ip, absorption current Ipa and constant current Ipb) for driving the first valve 29 independently of the current setting values (peak current Ip2, absorption current Ipa2 and constant current Ipb2) for driving the second valve 30. The microcomputer 51 also independently sets energization times for the current setting values according to the characteristics of the first valve 29 and the second valve 30. FIG.

However, the microcomputer 51 adjusts the control timing for opening or closing the first valve 29 and the second valve 30 by ensuring coincidence or difference between the timing for the second control IC 53 to implement control for turning the switches 81-83 on or off, and the timing for the first control IC 52 for implementing control for turning the switches 81-83 on or off. As a result, it is possible to implement control for changing the fuel injection ratio according to the above modes. By executing the above control, the control device 2 is configured to inject the fuel by changing the high injection ratio mode, the low injection ratio mode, and the boot injection mode described above.

Pressure reduction control during normal operation

Regarding 8th and 10 For example, the following description explains a processing operation in which the control device 2 provides control for reducing the internal pressure of the common rail 5 .

Normally, the control device 2 executes the control processing for the injection M in one cycle of the fuel injector 7 corresponding to the #1 cylinder of the first bank, the fuel injector 9 corresponding to the second bank cylinder #3, the fuel injector 10 corresponding to the first bank cylinder #4, and of the fuel injector 8 corresponding to the #2 cylinder of the second bank. Therefore, the fuel injectors 7, 9, 10 and 8 mainly inject the fuel in this order. 8th shows the other injections related to the multi-stage injection. These injections do not relate to the features of the present application, and description is omitted for the sake of simplicity.

8th 12 shows that the control device 2 detects that the internal pressure of the common rail 5 exceeds an upper pressure threshold based on the pressure sensor 14 or one of the built-in pressure sensors 7a to 10a of the fuel injectors 7 to 10 after the fuel injector 10 corresponding to cylinder #4 of the first bank injects the fuel and before the fuel injector 8 corresponding to cylinder #2 of the second bank injects the fuel.

In step S2 in 10 the microcomputer 51 determines that a pressure reduction request is issued. In step S3 in 10 For example, the microcomputer 51 sets a condition for energizing the second solenoid 32 that drives the second valve 30 and outputs a pressure reduction instruction and the condition for energizing the second solenoid 32 as a pressure adjustment instruction signal to the second control IC 53. In step S4 in 10 For example, the second control IC 53 uses the second valve drive units 58 and 59 to energize the targeted second solenoid 32 and thereby open the second valve 30. The internal pressure of the common rail thereby reduces in the rail pressure reduction mode.

The pressure reduction request occurs at timing t1 in 8th immediately before the fuel injector 10 of the second bank #2 injects the fuel. In step S4, the microcomputer 51 assumes that the targeted second solenoid 32 is the second solenoid 32 for the fuel injectors 7 to 9 corresponding to the cylinders #1 to #3 except for the cylinder #4. When the second solenoid 32 for the fuel injectors 7 to 9 is energized, the internal pressure of the common rail 5 reduces in the rail pressure reduction mode. The microcomputer 51 detects a signal from the pressure sensor 14 and energizes the target second solenoid 32 in steps S4 and S5 until the target pressure is reached.

As in 8th 1, the second control IC 53 temporarily stops energizing the second solenoid 32 to implement control to close the second valve 30 for the #3 cylinder belonging to the same bank as the #2 cylinder during the Fuel injection periods t2 and t3 for the fuel injector 8 corresponding to cylinder #2 of the second bank. This is because when the control is arranged to simultaneously open the second valves 30 for the fuel injectors 8 and 9 corresponding to cylinders #2 and #3 of the same second bank, the second solenoids 32 for the fuel injectors 8 and 9 corresponding to the same second Bank to be excited at the same time. The charging capacitor 75 of the second booster circuit 55 consumes increasing charging energy. A large thermal load is applied to the charging capacitor 75 . Operation reliability is likely to deteriorate.

The second control IC 53 is configured to reduce thermal stress on the charging capacitor 75 by providing control so as not to simultaneously energize the second solenoids 32 for the fuel injectors 8 and 9 corresponding to the same second bank. After the elapse of the fuel injection periods t2 and t3 for the fuel injector 8, the second control IC 53 again provides control to open the second valves 30 corresponding to the second bank for the fuel injectors 8 and 9, thereby reducing the interior pressure of the common rail 5. See periods t3 to t6 in 8th .

As in 8th 1, the fuel injector 7 corresponding to cylinder #1 of the first bank is used to inject the fuel at timing t4 and later. To this end, the first control IC 52 of the controller 2 controls the closing of the second valve 30 of the fuel injector 10 corresponding to cylinder #4 of the first bank during the fuel injection periods t4 and t5 for the fuel injector 7. The fuel injector 9 corresponding to cylinder #3 of the second bank is used to inject the fuel at timing t6 and later, as in 8th is shown. For this purpose, the second control IC 53 provides the control device 2 with control to close the second valve 30 of the fuel injector 8 corresponding to cylinder #2 of the same second bank at the timing t6 and later to inject the fuel from the fuel injector 9.

The microcomputer 51 acquires signals from the pressure sensor 14 and the built-in pressure sensors 7a to 10a. When the target pressure is reached, the microcomputer 51 determines that the pressure reduction request ends. In step S6, the microcomputer 51 stops energizing the second solenoid 32 as a target. See timing t7 in 8th . The following processing is similar to the injection control processing during normal operation.

During the period t1 to t4, in order to reduce the internal pressure of the common rail 5 according to the present embodiment, the second control IC 53 takes energizing periods t1 and t2 and t3 to t6 for the second solenoid 32 in the target fuel injection device 9 differently to the energizing periods t2 and t3 for the second solenoid 32 in the other fuel injector 8 belonging to the same bank during the normal injection control.

Similarly, during the period t4 to t6 to reduce the internal pressure of the common rail 5, the second control IC 53 takes the energizing periods t1 to t4 and t5 to t7 for the second solenoid 32 in the target fuel injector 10 differently to a part of the energizing periods t4 and t6 for the second solenoid 32 in the other fuel injector 7 belonging to the same bank during the normal injection control.

If the second control IC 53 excites a plurality of the second solenoids 32 using the second boosting voltage Vboost2 for the same charging capacitor 75, it is possible to distribute a current load to the charging capacitor 75 and reduce the thermal load. As a result, it is possible to reduce an internal pressure on the common rail 5 without thermally stressing the charging capacitor 75 as much as possible.

Processing operation in abnormal state

Regarding 11 For example, the following description explains a processing operation in an abnormal state that occurs due to a malfunction of the high-pressure fuel pump 4 stuck on the forced-feed side. When the microcomputer 51 of the control device 2 detects a complete forced-feed malfunction by detecting a value from the pressure sensor 14 or the built-in pressure sensors 7a to 10a as an abnormal value, the microcomputer 51 enters the full pressure reduction mode and proceeds to processing operation in the abnormal state.

In the full pressure reduction mode, the microcomputer 51 outputs the stop instruction to the first control IC 52 and the second control IC 53 as the pressure adjustment instruction signal. Then, the first control IC 52 stops providing control for driving the pump drive unit 60. At the same time, the second control IC 53 targets all fuel injectors 7 to 10 in pressure reduction driving and provides control for opening the second valve 30 by energizing the second solenoids 32 for the targeted fuel injectors 7 to 10.

11 12 shows an example of simultaneously performing processing for starting energization of the second solenoids 32 for driving the second valves 30 of all the fuel injectors 7 to 10 at the timing t11. The valve drive current is applied to the second solenoids 32 for the targeted fuel injectors 7 to 10 via the second valve drive units 58 and 59 . Therefore, the charging capacitor 75 greatly increases charging power consumption.

Advantageously, in order to mitigate an effect of the sudden increase in charging power consumption, the second control IC 53 adjusts the peak current Ip2 applied to the second solenoids 32 for the target fuel injectors 7 to 10 to be lower than the same for the normal one Injection is and provides control to extend the time to energize the pickup current Ipa2 by a predetermined time Ta.

A dashed line in 12 represents the valve drive current during normal injection control. A solid line in 12 represents the valve drive current in an abnormal state. The period Tp2b for energizing the absorbing current Ipa2 is longer than the period Tp2 during the normal injection control by a predetermined time Ta. For example, the peak current Ip2/2 for the valve drive current in an abnormal state is set to be half the peak current Ip2 for the valve drive current during normal injection control.

In an abnormal state, the second control IC 53 adjusts a peak current applied to the second solenoid 32 to be lower than the peak current Ip2 during normal injection control. It is possible to suppress a transient current more efficiently than the prior art and to reduce the thermal stress on the charging capacitor 75.

The accumulated amount of applied current increases because the time for applying the absorbing current Ipa2 is lengthened by a predetermined time Ta. An opening rate of the second valve 30 is adjusted based on the accumulated amount of applied current. It is possible to reliably implement control for opening the second valve 30 similar to the normal injection control.

It is advisable to set the predetermined time Ta according to characteristics of the fuel injectors 7-10. For example, it is a good practice to find structural or electrical characteristics of the fuel injectors 7 to 10 and store a record of a correlation between the characteristics and the predetermined time Ta in a non-volatile internal memory of the second control IC 53 . Then, the second control IC 53 is configured to refer to the correlation record, and the control to open the second valve 30 by controlling the predetermined time Ta based on actual measured values of the peak current Ip2/2 and the absorption current Ipa2 is more reliably implemented.

Modification of processing under normal injection controls

As above, the peak current for the valve drive current in an abnormal state is set to be lower than the peak current Ip for the valve drive current under normal injection control. Even if a pressure reduction request occurs under normal injection control, the second control IC 53 can set the peak current for the valve drive current to be lower than the peak current Ip under normal injection control, and implement control to change the time to energize the intake current Ipa2 to extend a predetermined time Ta. As explained above, it is a good practice to set the peak current Ip/2 for the valve drive current to half the peak current Ip under normal injection control and to lengthen the predetermined time Ta. With this, it is possible to obtain an effect similar to the above.

As above, the peak current Ip/2 for the valve drive current under normal injection control is set to half the peak current Ip when a pressure reduction request occurs under normal injection control or in an abnormal state. However, the reduction is not limited to half.

Modifications to processing under normal injection control or in an abnormal state

Another recommended method is to shift the timing for energizing the peak current Ip2 by shifting the timing for starting energization of each alternate solenoid 32 for driving each alternate valve 30 of the fuel injectors 7-10. For example, as in 13 1, it is good practice to begin energizing every other solenoid 32 to drive every other valve 30 of fuel injectors 7 and 10 at timing t21 and then to start energizing every other solenoid 32 to drive every other valve 30 of fuel injectors 8 and 9 at timing t22. Thereby, it is possible to suppress a transient current more efficiently than the prior art and to reduce the thermal stress on the charging capacitor 75 of the second booster circuit 55. Energization of each alternate solenoid 32 for fuel injectors 8 and 9 may begin prior to energization of each alternate solenoid 32 for fuel injectors 7 and 10 .

Usually, the common rail 5 is provided with a pressure reducing valve. However, it is not necessary to provide a pressure reducing valve for the common rail 5 if the low pressure chamber 36 for the fuel injectors 7 to 10 can inject the fuel according to the present embodiment. In addition to the configuration of the present embodiment, the common rail 5 may be provided with a pressure reducing valve.

Second embodiment

Regarding 14 and 15 the description below explains processing ope rations when the control device 2 provides control for reducing the internal pressure of the common rail 5 . As in 14 1, assume a case where a full forced-feed failure occurs after the controller 2 provides control for injecting the fuel from the fuel injector 7 corresponding to cylinder #1 of the first bank.

In S11 of 15 the controller 2 provides normal injection control. Meanwhile, the microcomputer 51 determines in S12 and S13 that no injection request occurs. Then in S14 of 15 the processing inputs a condition for energizing the second solenoid 32 to drive the second valve 30 and outputs a pressure reduction instruction as a pressure adjustment instruction signal together with the condition for energizing the second solenoid 32 to the second control IC 53 . In S<b>15 , the second control IC 53 energizes the targeted second solenoid 32 to open the targeted second valve 30 . As a result, the internal pressure of the common rail 5 is reduced in the full pressure reduction mode. As in S16 to S18 of 15 1, no injection request occurs and the internal pressure of the common rail 5 reaches a target pressure. Then, the controller 2 stops energizing the targeted second solenoid 32 to end the full pressure reduction mode.

However, when the microcomputer generates an injection request based on the sensor signal S in S16, the processing determines that the result is No. The processing stops energizing the target second solenoid 32, returns to S11, and is repeated in S11 to S13.

At this time, the control device 2 enters the full pressure reduction mode. Therefore, the microcomputer 51 responds to the injection request mentioned above. The first control IC 52 allows the first valve driver 57 to start energizing the first solenoid 31 for the fuel injector 9 . After the energization of the first solenoid 31 ends, the second control IC 53 allows the second valve drive unit 59 to start energizing the second solenoid 32 for the fuel injector 9 . See timings t31 and t32 in 14 .

The first control IC 52 uses setting values stored in internal memory to control the peak current Ip, the absorbing current Ipa, and the constant current Ipb. The second control IC 53 uses setting values stored in the internal memory to control the peak current Ip2, the absorbing current Ipa2, and the constant current Ipb2.

At timing t31, the internal memories of the first control IC 52 and the second control IC 53 store setting values for the modes specified by the microcomputer 51, such as the low injection ratio mode and the high injection ratio mode.

Therefore, the first control IC 52 is configured to implement control to open or close the first valve 29 in connection with the set value according to each mode. Then, the second control IC 53 is configured to implement control to open or close the second valve 30 in connection with the set value according to each mode. The microcomputer 51 is configured to continue the injection control by allowing the first control IC 52 to implement the control to open or close the first valve 29 and then reduce the internal pressure of the common rail 5 by the second control IC 53 enables the control to open or close the second valve 30 to be implemented.

The microcomputer 51 thereafter re-energizes the targeted second solenoid 32 in S14, thereby reducing the pressure of the common rail 5. See timings t32 and t33 in FIG 14 . When the injection request is generated again in response to the sensor signal S, the microcomputer stops energizing the targeted second solenoid 32 in S19 and proceeds to normal control in S11. The microcomputer 51 previously stores the above-mentioned setting values in the internal memories of the first control IC 52 and the second control IC 53. Therefore, injection control based on a request can be normally continued in the low injection ratio mode or in the high injection ratio mode . See timings t33 and t34 in 14 .

According to the present embodiment, the first control IC 52 stops energizing the first solenoid 31 to drive the first valve 29, and then the second control IC 53 starts energizing the second solenoid 32 to drive the second valve 30.

It is possible to implement the control for opening or closing the first valve 29 and the second valve 30 by sequentially energizing the first solenoid 31 and the second solenoid 32 while ensuring controllability at low or high injection ratios in each mode. It is also possible to respond to the pressure reduction request words while ensuring controllability at low or high injection ratios in any mode.

Third embodiment

The present embodiment explains a method for providing change control for the peak current Ip in an abnormal state. As above, the control device 2 generates a pressure reduction request and reduces the internal pressure of the common rail 5 under normal injection control or in an abnormal state. In this case controls as in 16 As shown, the second control IC 53 controls the pickup current Ipaa without controlling the peak current Ip under normal injection control. Then as in 16 As shown, the second control IC 53 is configured to control the peak current Ipm to be equal to the pickup current I-paa. As a result, the peak current Ipm can be changed to be much lower than the peak current Ip under normal injection control.

In this case, the second control IC 53 provides control for turning on or off the constant current switch 82 to apply the power supply voltage VB to the second solenoid 32, thereby implementing control for achieving the peak current Ipm. Therefore, there is no need to use the charging energy of the charging capacitor 75. As a result, it is possible to avoid consuming the charging energy of the charging capacitor 75 and greatly reduce the thermal load on the charging capacitor 75 .

Other embodiments

The present disclosure is not limited to the above embodiments, but can be modified in various ways within the spirit and scope of the disclosure. The following modifications or extensions are available, for example.

The configuration that returns the fuel from the fuel injectors 7 to 10 to the fuel tank 12 through the low-pressure line 38 has been described. However, the common rail 5 may be provided with a pressure reducing valve. When the common rail 5 is provided with a pressure reducing valve, the pressure can be reduced by the pressure reducing valve or the fuel injectors 7 to 10.

If the common rail 5 is not provided with a pressure reducing valve, it is advisable to reduce the pressure of the fuel injectors 7 to 10. The pressure sensor 14 may be available as the built-in pressure sensors 7 a to 10 a for the fuel injectors 7 to 10 of the pressure sensor 14 or as the pressure sensor 14 provided for the common rail 5 .

The first control IC 52 and the second control IC 53 may be configured on the same integrated circuit, may be configured on different integrated circuits, or may be integrated into the microcomputer 51 to be configured as a control section. The first control chamber 43 and the second control chamber 49 can be integrated into a single chamber.

Switches 81-84 and 91-93 have been described as, but not limited to, N-channel MOS transistors. Various transistors and switching elements can be used.

The configuration using only one second restriction 41a for the second path 41 has been described. However, multiple paths connecting the low pressure chamber 36 and the first control chamber 43 may be provided. The second restriction 41a may be provided for each of the paths. Namely, at least one second constriction 41a can be provided.

According to the above-mentioned embodiments, the internal combustion engine 11 uses four cylinders. Therefore, the cylinders #1 to #4 correspond to the fuel injectors 7 to 10. The first bank includes, but is not limited to, two cylinders #1 and #4, and the second bank includes two cylinders #2 and #4. The embodiments are also applicable to six cylinders.

The configurations of the embodiments can be combined as appropriate. A mode of omitting part of the above-mentioned embodiment can be adopted as an embodiment on condition that the omission is performed as long as the problem can be solved. All conceivable modes can be adopted as an embodiment without departing from the essence of the invention, which is identified by the formulations described in the scope of the claims.

It should be understood that although the processes of the embodiments of the present disclosure have been described herein as involving a specific sequence of steps, other alternative embodiments involving various other sequences of these steps and/or additional steps not disclosed herein are within further consideration of the steps of the present disclosure should be considered lying.

Claims (9)

A fuel injection control device configured to implement injection control for injecting fuel stored in a common rail (5) into an internal combustion engine (11) using a plurality of fuel injectors (7 to 10), each of the fuel injectors having a first A solenoid (31), a first valve (29), a second solenoid (32) and a second valve (30), the fuel injection control device comprising: a first control section (52) configured to energize the first solenoid to drive the first valve and control fuel injection timing under normal injection control; and a second control section (53) configured to apply a peak current (Ip2) indicating a maximum current to the second solenoid using charging power of a charging section (75) and then apply a pickup current (Ipa2) lower than that Peak current is to drive the second valve to control an injection ratio of the fuel under the normal injection control, where, when an internal pressure of the common rail is reduced under the normal injection control or under an abnormal condition different from the normal injection control, the first control section is configured to implement control for closing the first valve, and the second control portion is configured to energize the second solenoid for at least one targeted fuel injector among the fuel injectors and implement control for opening the second valve, wherein, when the internal pressure of the common rail is reduced under the normal injection control or under the abnormal condition different from the normal injection control, the second control section is configured to implement control to adjust the peak current applied to the second solenoid for the targeted fuel injector to be lower than the peak current under the normal injection control, and to adjust a time to Applying the pickup current to extend a predetermined period of time. Fuel injection control device claim 1 wherein when the internal pressure of the common rail is reduced under the normal injection control or under the abnormal condition, the second control section is configured to adjust the peak current to be half the peak current under the normal injection control. Fuel injection control device claim 1 wherein when the internal pressure of the common rail is reduced under the normal injection control or under the abnormal condition, the second control section is configured to control the intake current without controlling the peak current using the charging power of the charging section (75). Fuel injection control device according to one of Claims 1 until 3 , wherein the second control portion is configured to adjust the predetermined amount of time based on characteristics of the fuel injector. A fuel injection control device configured to implement injection control for injecting fuel stored in a common rail into an internal combustion engine using a plurality of fuel injectors, each of the fuel injectors having a first solenoid (31), a first valve (29 ), a second solenoid (32) and a second valve (30), the fuel injection control device comprising: a first control portion (52) configured to apply a current to the first solenoid to drive the first valve (29). , and to control fuel injection timing under normal injection control; and a second control section (53) configured to energize each of the second solenoids using charging energy of an identical charging section (75) under the normal injection control and drive the second valve (30) of each of the fuel injectors (8, 9), to implement a control for changing an injection ratio of the fuel, wherein when the internal pressure of the common rail is reduced under the normal injection control or under an abnormal condition different from the normal injection control, the first control section is configured to implement control for closing the first valve, and the second control portion is configured to implement control for energizing the second solenoid of at least one targeted fuel injector among the fuel injectors to open the second valve, and during a period iode in which the internal pressure of the common rail is reduced, the second control section is configured to select an energization period for the second solenoid of the target fuel injection device from an energization period for the second solenoid of the other fuel to distinguish injection device under the normal injection control. Fuel injection control device claim 5 wherein each bank includes two of multiple cylinders corresponding to the fuel injectors, the second control section is configured to differently control energization periods for the second solenoids of the two fuel injectors corresponding to the two cylinders of the same bank. Fuel injection control device claim 5 or 6 wherein when the first control section energizes the first solenoid to drive the first valve in the abnormal state, the first control section is configured to stop energizing the first solenoid to drive the first valve, and the second control section is configured to then start energizing the second solenoid to drive the second valve. Fuel injection control device according to one of Claims 1 until 7 wherein the fuel injection device includes: a nozzle needle (25) configured to allow an injection hole (47) to inject the fuel supplied from the common rail through a high-pressure fuel passage (35); a control chamber (43, 49) configured to store fuel behind the nozzle needle and to control fuel injected from the injection hole of the nozzle needle; an oil pressure driven valve (27) provided within the control chamber and configured to be driven by the pressure of the high pressure fuel passage and the control chamber; a first path (45) provided within the oil pressure driven valve within the control chamber; a first restriction (45a) configured to limit the first path; at least one second path (41) connecting the control chamber to a low pressure chamber (36) without passing through an interior of the oil pressure driven valve; at least one second restriction (41a), each configured to limit the second path; and the low-pressure chamber (36) is configured to discharge the fuel not injected from the injection hole, the first control section being configured to energize the first solenoid to drive the first valve and the second control section being configured to energize the second solenoid energize to drive the second valve to implement control for connecting and disconnecting the second orifice; and when the internal pressure of the common rail is reduced, the first solenoid is configured to implement a control to close the first valve, and the second solenoid is configured to implement a control to open the second valve to correspondingly operate the oil pressure driving valve to connect the second restriction to connect the high-pressure fuel passage, the control chamber and the low-pressure chamber from the common rail, and drain the fuel from the low-pressure chamber without injecting the fuel from the injection hole of the nozzle needle into the internal combustion engine, to reduce an internal pressure of the common rail. Fuel injection control device according to one of Claims 1 until 8th wherein, the internal pressure of the common rail is reduced under the normal injection control or under the abnormal condition, the second control section is configured to implement the control to reduce the peak current applied to the second solenoid for the target fuel injector to be set to be lower than the peak current under the normal injection control when the internal pressure of the common rail is not reduced, and to extend time for applying the pick-up current by the predetermined period of time.

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