JP6915474B2 - Fuel injection control device and fuel injection control system - Google Patents

Description

The disclosure herein relates to a fuel injection control technique for controlling a fuel injection device.

Conventionally, for example, Patent Documents 1 and 2 disclose a fuel injection device capable of switching the inclination of an injection rate increase in fuel injection. The fuel injection device of Patent Document 1 is provided with two solenoid valves each having a drive unit. The control device that controls this fuel injection device increases the injection rate in fuel injection by changing the control that inputs drive energy to only one solenoid valve and the control that inputs drive energy to both solenoid valves. Switch the tilt.

On the other hand, the fuel injection device of Patent Document 2 has only one drive unit. The control device that controls the fuel injection device changes the fuel path through which the fuel flows out from the pressure control chamber by controlling the driving energy input to the driving unit to be increased or decreased. As a result, even if there is only one drive unit, it is possible to switch the inclination of the injection rate increase.

Japanese Unexamined Patent Publication No. 2000-297719 JP-A-2017-150390

By the way, when controlling the fuel injection device in which the slope of the increase in the injection rate is switched by the increase or decrease of the drive energy as in Patent Document 2, it is important to set the drive energy to realize the slope of each increase in the injection rate. However, the threshold value of the driving energy at which the slope of the increase in the injection rate is switched is unlikely to be constant due to the machine difference of each fuel injection device and the secular change that occurs in each fuel injection device. Therefore, it may be difficult to carry out fuel injection with a desired slope of increase in injection rate.

An object of the present disclosure is to provide a fuel injection control device capable of avoiding a situation in which fuel injection is performed due to an erroneous inclination of an injection rate increase.

In order to achieve the above object, one aspect disclosed is to inject fuel from the injection hole (29) toward the combustion chamber (2b) of the engine (2), and the inclination of the injection rate increase in the fuel injection is the driving unit. A fuel injection control device that controls a fuel injection device (10) that can be switched by the drive energy input to (30), the drive control unit (72) that controls the input of drive energy to the drive unit, and a drive. The fuel injection device switches between the injection determination unit (73), which determines the correlation between the drive energy input by the control unit and the inclination of the injection rate increase caused by the input of the drive energy, from the fluctuation amount of the engine rotation speed. The fuel injection control device includes an energy setting unit (74) that sets a set value of the drive energy that realizes the inclination of each injection rate increase based on the determination result of the injection determination unit.

Further, in one disclosed aspect, fuel is injected from the injection hole (29) toward the combustion chamber (2b) of the engine (2), and the inclination of the injection rate increase in the fuel injection is input to the drive unit (30). A fuel injection device (10) that can be switched by the drive energy to be generated, a drive control unit (72) that controls the input of the drive energy to the drive unit, a drive energy input by the drive control unit, and a drive energy input. A set value of the drive energy that realizes the inclination of each injection rate increase that can be switched by the injection determination unit (73) that determines the correlation with the generated inclination of the injection rate increase from the fluctuation amount of the engine rotation speed and the fuel injection device. Is a fuel injection control system including an energy setting unit (74) for setting based on a determination result of the injection determination unit, and a fuel injection control device (100) for controlling the fuel injection device.

If the inclination of the injection rate increase differs in the fuel injection performed by the fuel injection device, the mode of fluctuation that occurs in the engine speed also differs. Therefore, in each of the above aspects, the correlation between the drive energy input to the drive unit and the slope of the injection rate increase caused by the input of the drive energy is determined from the fluctuation amount of the engine speed. Then, based on the determination result of the correlation between the drive energy and the slope of the injection rate increase, the set value of the drive energy that realizes the slope of each injection rate increase is set.

As described above, if the drive energy is actually input to the drive unit and a set value of the drive energy is set based on the determination result, the set value is the injection rate desired by the current fuel injection device. It can be a value that correctly realizes the slope of the rise. Therefore, it is possible to avoid a situation in which fuel injection is performed with an erroneous inclination of the injection rate increase due to a machine difference, aged change, or the like.

The reference numbers in parentheses are merely examples of the correspondence with the specific configuration in the embodiment described later, and do not limit the technical scope at all.

It is a figure which shows the whole structure of the fuel injection control system including a fuel injection device and a control device. It is a vertical sectional view of a fuel injection device. It is a figure which shows the state of the valve mechanism in the low-speed valve opening mode in which the inclination of the injection rate rise becomes small. It is a figure which shows the state of the valve mechanism in the high-speed valve opening mode in which the inclination of the injection rate rise becomes large. It is a block diagram which shows the functional block constructed in the control device. It is a figure for demonstrating the correlation between the driving energy input in each valve opening mode, and the threshold value at which the state of a valve mechanism is switched. It is a figure which shows typically the change of the drive energy which the drive control part applies to the drive part in the detection injection process. It is a figure which shows typically the influence which the change of the slope of the injection rate increase in fuel injection has on the fluctuation of the rotation speed. It is a flowchart which shows the detail of the correlation detection process for updating a setting value. It is a flowchart which shows the detail of the injection process for detection. It is a flowchart which shows the detail of the detection process which detects a high-low threshold value. It is a flowchart which shows the detail of the detection process which detects the valve opening threshold value. It is a figure for demonstrating the detail of the process of searching for a high-low threshold value and a valve opening threshold value. It is a flowchart which shows the detail of the correlation detection processing performed in the initial learning. It is a figure which shows the modification of the fuel injection device.

The control device 100 according to the embodiment of the present disclosure is used in the fuel injection control system 1 shown in FIG. By controlling the fuel injection device 10, the control device 100 causes each combustion chamber 2b of the diesel engine (hereinafter, “engine 2”), which is an internal combustion engine, to supply the fuel stored in the fuel tank 4. The engine 2 is mounted on a vehicle as a power source for generating power for traveling, for example. The fuel injection control system 1 includes a feed pump 5, a high-pressure fuel pump 6, a common rail 3, a crank angle sensor 7, and the like together with the fuel injection device 10 and the control device 100.

The feed pump 5 is, for example, a trochoidal electric pump. The feed pump 5 is built in the high pressure fuel pump 6. The feed pump 5 pumps light oil as fuel stored in the fuel tank 4 to the high-pressure fuel pump 6. The feed pump 5 may be separate from the high-pressure fuel pump 6 and may be arranged inside, for example, the fuel tank 4.

The high-pressure fuel pump 6 is, for example, a plunger type pump. The high-pressure fuel pump 6 is driven by the output shaft of the engine 2. The high-pressure fuel pump 6 is connected to the common rail 3 by a fuel pipe 6a. The high-pressure fuel pump 6 further boosts the fuel supplied by the feed pump 5 and supplies it to the common rail 3 as high-pressure fuel.

The common rail 3 is connected to a plurality of fuel injection devices 10 via a high-pressure fuel pipe 3b. The common rail 3 is connected to the fuel tank 4 via a surplus fuel pipe 8a. The common rail 3 temporarily stores the high-pressure fuel supplied from the high-pressure fuel pump 6 and distributes the high-pressure fuel to each fuel injection device 10 while maintaining the pressure. The common rail 3 is provided with a pressure sensor 3a and a pressure reducing valve 8. The pressure sensor 3a detects the fuel pressure stored in the common rail 3. The detection signal by the pressure sensor 3a is taken into the control device 100. When the fuel pressure of the common rail 3 is higher than the target pressure, the pressure reducing valve 8 discharges the surplus fuel to the surplus fuel pipe 8a.

The crank angle sensor 7 is combined with the signal rotor 7a to detect the rotation of the crankshaft of the engine 2. The signal rotor 7a is formed in a disk shape and rotates integrally with the crankshaft of the engine 2, for example. A large number of protrusions (for example, 36 teeth) are formed on the outer peripheral portion of the signal rotor 7a. The crank angle sensor 7 is an electromagnetic pickup that outputs a signal according to the approach and separation of the protrusions. The detection signal from the crank angle sensor 7 is taken into the control device 100.

The fuel injection device 10 shown in FIGS. 1 and 2 injects fuel from the injection hole 29 toward the combustion chamber 2b under the control of the control device 100. As will be described later, the fuel injection device 10 changes the throttle state of the valve mechanism 60 according to the magnitude of the drive energy input to one drive unit 30, and gradually switches the inclination of the injection rate increase in the fuel injection. (See FIGS. 3 and 4). The fuel injection device 10 includes a valve body 20 and a nozzle needle 50 together with the drive unit 30 and the valve mechanism 60 described above.

The valve body 20 is formed by combining a plurality of members formed of a metal material. In addition to the injection hole 29, the valve body 20 includes a high-pressure fuel passage 21, a high-pressure chamber 21a, a supply passage 22, a control passage 23, a low-pressure chamber 24, a low-pressure passage 26, a control chamber 27, and a valve chamber 28. Is provided.

The injection hole 29 is formed at the tip end portion in the insertion direction in the valve body 20 inserted into the head member 2a. A plurality of injection holes 29 are provided radially from the inside to the outside of the valve body 20. Each injection hole 29 injects high-pressure fuel toward the combustion chamber 2b. The high-pressure fuel is atomized by passing through the injection hole 29, and is easily mixed with air.

The high-pressure fuel passage 21 is connected to the high-pressure fuel pipe 3b. The high-pressure fuel passage 21 supplies the high-pressure fuel supplied from the common rail 3 through the high-pressure fuel pipe 3b to the high-pressure chamber 21a. The high pressure chamber 21a is a columnar space accommodating the nozzle needle 50. The high pressure chamber 21a is filled with high pressure fuel supplied through the high pressure fuel passage 21. The high-pressure chamber 21a distributes high-pressure fuel to the injection hole 29.

The supply communication passage 22 communicates the high-pressure fuel passage 21 with the valve chamber 28. The supply passage 22 limits the flow rate of fuel flowing from the high-pressure fuel passage 21 into the valve chamber 28 by the orifice 22a. The control communication passage 23 communicates the control chamber 27 and the valve chamber 28 with each other. The control communication passage 23 limits the fuel flow rate flowing between the control chamber 27 and the valve chamber 28 by the orifice 23a.

The low pressure chamber 24 is connected to the return pipe 8b, and the surplus fuel is circulated to the return pipe 8b. The low pressure chamber 24 is filled with fuel having a lower pressure than the high pressure chamber 21a. The low-pressure communication passage 26 communicates the valve chamber 28 and the low-pressure chamber 24. The fuel in the valve chamber 28 is discharged to the low pressure chamber 24 through the low pressure communication passage 26. The low pressure communication passage 26 limits the fuel flow rate discharged from the valve chamber 28 by the orifice 26a.

The control chamber 27 is a flat disk-shaped space located on the opposite side of the injection hole 29 with the nozzle needle 50 in between. High-pressure fuel flowing through the high-pressure fuel passage 21 is supplied to the control chamber 27 through the supply passage 22, the valve chamber 28, and the control passage 23. The control chamber 27 is filled with fuel.

The valve chamber 28 is a multi-stage columnar space provided between the low pressure chamber 24 and the control chamber 27. The valve chamber 28 is filled with the fuel flowing through the supply passage 22. The partition wall for partitioning the valve chamber 28 is provided with an upper opening wall portion 25a and a lower opening wall portion 25b. One end of each of the supply passage 22 and the low pressure passage 26 is opened in the upper opening wall portion 25a. One end of the control communication passage 23 is open in the lower opening wall portion 25b.

The nozzle needle 50 is formed in a cylindrical shape by a metal material. The nozzle needle 50 is housed in the high-pressure chamber 21a, and receives a force from the high-pressure fuel in the high-pressure chamber 21a in the direction of opening the injection hole 29 (hereinafter, “valve opening direction”). The nozzle needle 50 is formed with a needle pressure receiving surface 51. The needle pressure receiving surface 51 receives a force in the direction of closing the injection hole 29 (hereinafter, “valve closing direction”) from the high-pressure fuel filled in the control chamber 27.

The nozzle needle 50 is pushed up by the fuel in the high pressure chamber 21a due to the depressurization of the control chamber 27, and is displaced in the valve opening direction. As a result, the high-pressure fuel filled in the high-pressure chamber 21a is injected from the injection hole 29 toward the combustion chamber 2b. On the other hand, according to the pressure recovery of the control chamber 27, the nozzle needle 50 is pushed down in the valve closing direction. As a result, fuel injection from the injection hole 29 is stopped. In this way, the nozzle needle 50 is displaced relative to the valve body 20 along the axial direction due to the fluctuation of the fuel pressure in the control chamber 27, and opens and closes the injection hole 29.

The drive unit 30 drives the valve mechanism 60 by a telescopic operation. The drive unit 30 has a piezo actuator 31 and a drive transmission pin 32. The piezo actuator 31 has a piezoelectric element laminate. The drive voltage, which is the output of the control device 100, is input to the piezo actuator 31, and the drive energy corresponding to the drive voltage is charged. The drive amount (extension amount) of the piezo actuator 31 increases as the input amount of drive energy increases.

The drive transmission pin 32 is a pressing shaft portion that transmits the expansion / contraction operation of the piezo actuator 31 to the valve mechanism 60. The tip of the drive transmission pin 32 is abutted against the center of the top surface of the first control valve body 61, which will be described later. Due to the extension of the piezo actuator 31 due to the input of drive energy, the drive transmission pin 32 is displaced in the direction of protruding into the valve chamber 28. On the other hand, due to the contraction of the piezo actuator 31 due to the electric discharge, the drive transmission pin 32 is displaced in the direction of retracting from the valve chamber 28.

The valve mechanism 60 is housed in the valve chamber 28. The valve mechanism 60 functions as a three-way valve that switches between allowing and shutting off the communication of the supply communication passage 22 and the low pressure communication passage 26 to the valve chamber 28. The valve mechanism 60 is composed of a first control valve body 61, a hydraulically actuated valve body 62, a second control valve body 63, an intermediate member 64, coil springs 65a, 65b, and the like. Each configuration of the valve mechanism 60 is arranged so as to be coaxial with each other.

The first control valve body 61 is composed of a valve closing member 61a formed in a partially spherical shape by a metal material or the like, and a fitting member 61b or the like formed in a columnar shape by a metal material or the like. The first control valve body 61 takes off and seats on the upper opening wall portion 25a by driving the drive unit 30, and opens and closes one end of the low-voltage communication passage 26 opened in the upper opening wall portion 25a. According to the opening of the first control valve body 61, the fuel in the valve chamber 28 can flow out to the low pressure chamber 24. On the other hand, according to the closing of the first control valve body 61, the communication between the valve chamber 28 and the low pressure chamber 24 is cut off.

The hydraulically actuated valve body 62 is formed of a metal material or the like into a flat columnar shape as a whole. The hydraulically actuated valve body 62 is a hydraulically driven valve that is displaced by a pressure difference generated in the surroundings. The hydraulically actuated valve body 62 is slidable with respect to the outer peripheral surface of the first control valve body 61, and is independently displaceable with respect to the first control valve body 61. The hydraulically actuated valve body 62 is displaced in the axial direction due to the pressure difference between the upper and lower sides, and is detached and seated on the upper opening wall portion 25a to open and close one end of the supply communication passage 22 opened in the upper opening wall portion 25a.

A plurality of (two) communication passages 62a and 62b are formed in the hydraulically actuated valve body 62. The low-speed communication passage 62a axially penetrates between the upper surface and the lower surface of the hydraulically actuated valve body 62. A first orifice 66a is formed in the low-speed communication passage 62a. The first orifice 66a controls the fuel flow rate through the low-speed communication passage 62a. The high-speed communication passage 62b connects the upper surface of the hydraulically actuated valve body 62 to the center hole. A second orifice 66b is formed in the high-speed communication passage 62b. The second orifice 66b controls the fuel flow rate through the high-speed communication passage 62b.

The second control valve body 63 is formed of a metal material or the like into a flat columnar shape as a whole. An intermediate member 64 is inserted into the insertion hole provided in the second control valve body 63. The second control valve body 63 switches the throttle state of the valve mechanism 60 from the first throttle state (see FIG. 3) to the second throttle state (see FIG. 4) by leaving the hydraulically actuated valve body 62.

In the first throttle state, the flow of fuel in the low-speed communication passage 62a is permitted, while the flow of fuel through the high-speed communication passage 62b is blocked. As a result, the fuel flow rate flowing out from the valve chamber 28 to the low pressure chamber 24 is limited only by the first orifice 66a. On the other hand, in the second throttle state, the fuel of the valve chamber 28 can flow into the high-speed communication passage 62b, and both the first orifice 66a and the second orifice 66b direct the fuel of the valve chamber 28 toward the low pressure chamber 24. Distribute. According to the above, in the second throttle state, the outflow flow rate from the valve chamber 28 increases as compared with the first throttle state, and the pressure in the control chamber 27 drops at a higher speed than in the first throttle state.

The intermediate member 64 is formed in a substantially columnar shape by a metal material or the like. The intermediate member 64 has a rod portion 64a. The tip of the rod portion 64a is pressed against the fitting member 61b. The coil springs 65a and 65b are formed in a cylindrical spiral shape. The coil spring 65a urges the first control valve body 61 toward the upper opening wall portion 25a via the intermediate member 64. The coil spring 65b urges the second control valve body 63 toward the first control valve body 61.

As described above, the fuel injection device 10 described above can perform fuel injection in a plurality of valve opening modes having different injection rate characteristics (inclinations of increase in injection rate) from each other while the vehicle is running. As an example, the plurality of valve opening modes for traveling include a low-speed valve opening mode (see FIG. 3) and a high-speed valve opening mode (see FIG. 4). The slope of the injection rate increase in the low-speed valve opening mode is gentler than the slope of the injection rate increase in the high-speed valve opening mode. Assuming that the drive energy input to the drive unit 30 in the low-speed valve opening mode is the first drive energy V _Lo and the drive energy input to the drive unit 30 in the high-speed valve opening mode is the second drive energy V _Hi . The second drive energy V _Hi is set to a value larger than that of the first drive energy V _Lo.

The fuel injection rate is the amount of fuel injected from the fuel injection device 10 per hour. The slope of the increase in the injection rate is the slope in the process in which the fuel injection rate gradually increases from 0 after the start of injection. The inclination of the injection rate increase is closely related to the step-down speed of the control chamber 27 and the valve opening speed of the nozzle needle 50, and increases as the step-down speed and the valve opening speed increase.

In the low-speed valve opening mode shown in FIG. 3, _{the drive unit 30 charged with the first drive energy V Lo} causes the first control valve body 61 to be separated from the upper opening wall portion 25a. On the other hand, since the drive amount of the drive unit 30 is small, the second control valve body 63 remains seated on the flood control valve body 62. According to the above, since the valve mechanism 60 is in the first throttle state, the step-down speed of the valve chamber 28 and the control chamber 27, and thus the valve opening speed of the nozzle needle 50, is lower than that of the high-speed valve opening mode. As a result, the slope of the injection rate increase becomes small (smooth).

_{On the other hand, in the drive unit 30 to which the second drive energy VHi} was input in the high-speed valve opening mode shown in FIG. 4, the first control valve body 61 was separated from the upper opening wall portion 25a due to the increase in the drive amount. Then, the second control valve body 63 is separated from the hydraulically operated valve body 62. As a result, since the valve mechanism 60 is in the second throttle state, the step-down speed of the valve chamber 28 and the control chamber 27, and thus the valve opening speed of the nozzle needle 50, is higher than that of the low-speed valve opening mode. As a result, the slope of the injection rate increase becomes larger (steeper) than in the low-speed valve opening mode.

The control device 100 shown in FIGS. 1 and 5 includes an arithmetic circuit mainly composed of a microcomputer or a microcontroller, and a drive circuit for applying a drive voltage to the drive unit 30 of each fuel injection device 10. The arithmetic circuit is provided with a processor, RAM, a rewritable non-volatile memory device, an input / output interface, and the like. The control device 100 executes a fuel injection control program stored in the memory device by a processor, and performs functional blocks such as an information acquisition unit 71, a drive control unit 72, an injection determination unit 73, an energy setting unit 74, and a timing determination unit 75. To construct.

The information acquisition unit 71 acquires information related to the operating state of the engine 2 from various sensors. For example, the information acquisition unit 71 calculates the number of rotations (rotational speed) of the crankshaft per unit time by a process of measuring the interval time of the signal detected by the crank angle sensor 7. In addition, the information acquisition unit 71 calculates the fuel pressure supplied to each fuel injection device 10 by the process of measuring the signal detected by the pressure sensor 3a. Further, the information acquisition unit 71 acquires information indicating the mileage traveled by the vehicle, information indicating the cooling water temperature and lubricating oil temperature of the engine 2, information indicating the accelerator opening degree, diagnostic information indicating an abnormality of the engine 2, and the like. ..

The drive control unit 72 determines the mode of the drive signal applied to the fuel injection device 10 based on various information acquired by the information acquisition unit 71, and controls the drive energy input to each drive unit 30. Specifically, the drive control unit 72 selects the valve opening mode of the fuel injection device 10 and outputs a drive signal corresponding to the selected valve opening mode to the fuel injection device 10. When the drive control unit 72 performs fuel injection in the low-speed valve opening mode, the first drive energy V _Lo is input to each drive unit 30, and when fuel injection is performed in the high-speed valve opening mode, the drive control unit 72 inputs the fuel injection. , The second drive energy V _Hi is input to each drive unit 30. By switching the drive energy in this way, the drive control unit 72 makes each fuel injection device 10 realize the intentional inclination of each injection rate increase.

Here, each magnitude of the first drive energy V _Lo and the second drive energy V _Hi is a preset value set in advance using at least one of the valve opening threshold value Th _Lo and the high / low threshold value Th _{Hi shown in FIG.} .. The valve opening threshold Th _Lo is a value indicating a boundary between the driving energy that does not open the injection hole 29 and the driving energy that opens the injection hole 29 in the low-speed valve opening mode. The high / low threshold value Th _Hi is a value indicating a boundary between the driving energy for opening the injection hole 29 in the low-speed valve opening mode and the driving energy for opening the injection hole 29 in the high-speed valve opening mode. That is, the high / low threshold value Th _Hi is the drive energy for switching the throttle state of the valve mechanism 60 in the fuel injection device 10, and the drive in which the number of passages in the communication state among the low speed communication passage 62a and the high speed communication passage 62b changes. It is energy.

However, each value of the driving energy that becomes the valve opening threshold Th _Lo and the high / low threshold Th _Hi becomes constant due to the machine difference of each fuel injection device 10 and the secular change that occurs in each fuel injection device 10. hard. Therefore, it is desirable that the first drive energy V _Lo and the second drive energy V _Hi are initially set for each fuel injection device 10 and appropriately adjusted in the process of use. Therefore, the control device 100 performs initial learning and updating of _{the valve opening threshold Th Lo} and the high / low threshold Th _Hi based on the correlation detection process for detecting the correlation between the input drive energy and the slope of the injection rate increase.

For such processing, the drive control unit 72 shown in FIG. 5 determines a single fuel injection as the injection for correlation detection at the timing when the engine 2 is in the deceleration non-injection state due to the accelerator pedal being turned off or the like. Perform multiple times with an interval of. _{At this time, the drive control unit 72 changes the drive voltage (drive energy V h} , V _l ) for correlation detection stepwise each time while maintaining the length of the injection period substantially constant (see FIG. 7). .. It should be noted that the vehicle does not travel with _{the driving energies V h} and V _{l for correlation detection.}

The injection determination unit 73 determines the correlation between the drive energy input by the drive control unit 72 and the slope of the injection rate increase caused by the input of the drive energy from the amount of fluctuation in the engine speed (see FIG. 8). .. The injection determination unit 73 at least determines whether the inclination of the injection rate increase is for high-speed valve opening, low-speed valve opening, or no injection, based on the amount of fluctuation in the rotation speed of the engine 2. More specifically, even if the drive energy is input to the drive unit 30 in the deceleration-free injection state, the fuel injection is not performed if _{the drive energy is less than the valve opening threshold Th Lo (see FIG. 6).} Therefore, the number of revolutions continues to decelerate at a substantially constant speed (see the solid line in FIG. 8).

On the other hand, if the driving energy _{exceeds the valve opening threshold Th Lo} , the increase fluctuation of the rotation speed is detected by the execution of fuel injection (see FIG. 6). At this time, if the driving energy further _{exceeds the high / low threshold value Th Hi} , more fuel is supplied immediately after the start of valve opening than in the case where the drive energy is less than the high / low threshold value Th _Hi. Therefore, the amount of increase fluctuation of the rotation speed becomes large. The injection determination unit 73 determines whether the fuel injection is performed in the high-speed valve opening mode or the low-speed valve opening mode based on the amount of increase fluctuation of the engine speed (see FIG. 8).

The injection determination unit 73 detects the correlation between the drive energy and the slope of the increase in the injection rate in parallel with the process in which the drive control unit 72 increases or decreases the drive energy stepwise, whereby the valve opening threshold Th _Lo and the high / low threshold are set. Search for Th _Hi. More specifically, according to the gradual increase (or decrease) of the drive energy, at a certain number of times (see FIG. 7n1), the drive energy passes through _{the true valve opening threshold Th Lo of the fuel injection device 10.} .. At this time, the injection determination unit 73 can determine whether or not fuel injection has been performed from the fluctuation in the number of revolutions, and can detect that the non-injection state has disappeared (see FIG. 8). Therefore, the injection determination unit 73 sets the driven energy input at the timing when the fuel injection is detected as the searched valve opening threshold Th _Lo .

Similarly, according to the gradual increase (or decrease) of the drive energy, at a certain number of times (see FIG. 7n2), the drive energy passes through _{the true high-low threshold Th Hi of the fuel injection device 10.} At this time, the injection determination unit 73 can determine the change in the magnitude of the increase inclination of the injection rate from the fluctuation of the rotation speed and detect the transition of the valve opening mode (see FIG. 8). _{Therefore, the injection determination unit 73 sets the searched high / low threshold value Th Hi} as the drive energy input at the timing when the change of the slope of the injection rate increase is detected.

The energy setting unit 74 sets the first drive energy V _Lo and the second drive energy V _Hi , which are the set values of the drive energy, based on the determination result of the injection determination unit 73. Specifically, the energy setting unit 74, the setting value of the second drive energy V _Hi to realize high-speed opening mode is set based on the height threshold Th _Hi. The second drive energy V _Hi is set by a process of adding a predetermined constant m to the high / low threshold value Th _{Hi (see FIG. 6). The energy setting unit 74 sets the set value of the first drive energy V Lo} that realizes the low-speed valve opening mode based on both the high / low threshold value Th _Hi and the valve opening threshold value Th _Lo. The second drive energy V _Hi is set to an intermediate value between the high and low thresholds Th _Hi and the valve opening threshold Th _{Lo (see FIG. 6).}

The timing determination unit 75 determines the timing of initial setting of _{the first drive energy V Lo} and the second drive energy V _{Hi and the update timing thereof.} The amount of deterioration of the fuel injection device 10 occurs in proportion to the mileage. Therefore, as an example, when the integrated mileage D (see FIG. 9) from the previous update exceeds a certain distance, which is the update threshold value, based on the mileage acquired by the information acquisition unit 71. It is determined that the set value needs to be updated. The update threshold value that defines the detection interval is determined by conformity based on durability test data or the like performed in advance.

_{Hereinafter, the details of the correlation detection process in which the control device 100 sets the respective drive energies V Lo} and V _Hi based on the determination of the timing determination unit 75 will be described with reference to FIGS. 1 and 6 based on FIGS. 9 to 14. explain.

The correlation detection process shown in FIG. 9 is started by the control device 100 based on, for example, the ignition being turned on by the user of the vehicle and the engine 2 being started. In S101 of the correlation detection process, the integrated mileage D is calculated, and the process proceeds to S102. In S102, it is determined whether or not the integrated mileage D exceeds a predetermined update threshold value. If the integrated mileage D is equal to or less than the update threshold value, the process proceeds to S112. In S112, it is determined that the detection has not been performed, and the correlation detection process is terminated.

On the other hand, if it is determined in S102 that the integrated mileage D exceeds the update threshold value, the process proceeds to S103. In S103 to S108, it is determined in order whether or not the operating state of the engine 2 is a state suitable for correlation detection. Specifically, in S103, it is determined whether or not the state of the engine is a normal state based on the diagnostic information and the like. The reason why the correlation detection is not performed at the time of abnormality is to avoid a situation in which _{the wrong drive energies V Hi} and V _{Lo are set due to the wrong detection.} If the state of the engine 2 is not normal, the process proceeds to S112 to end the correlation detection process. On the other hand, if the state of the engine 2 is normal, the process proceeds to S104.

In S104, it is determined whether or not the cooling water temperature is within a predetermined range. According to the change in the cooling water temperature, the amount of energy loss generated during combustion changes, and the rotation fluctuation in the single injection becomes different. In order to prevent such a situation, the temperature range in which the correlation detection is performed is predetermined. If the cooling water temperature is out of the specified range, the process proceeds to S112 and the correlation detection process is terminated. On the other hand, if the cooling water temperature is within the specified range, the process proceeds to S105.

In S105, it is determined whether or not the clutch is in the released state by the control of the control device 100. The clutch is a configuration provided in the drive system between the crankshaft and the drive wheels. When the clutch is opened, the torque transmission from the drive wheels of the vehicle to the engine 2 is cut off or reduced. As described above, the situation where the road noise is transmitted from the drive wheels to the engine 2 and the fluctuation of the rotation speed due to the single injection becomes difficult to see can be avoided. If it is determined in S105 that the clutch is in the connected state, the process proceeds to S112 and the correlation detection process is terminated. On the other hand, if the clutch is in the open state, the process proceeds to S106.

In S106, the fuel injection command for driving the vehicle disappears, and it is determined whether or not the fuel injection is temporarily cut in the non-injection control state. If the fuel injection is continued, the process proceeds to S112 to end the correlation detection process. On the other hand, for example, when it is determined that the accelerator pedal is no longer operated during traveling and the non-injection control state is reached, the process proceeds to S107.

In S107, it is determined whether or not the pressure of the common rail 3 (hereinafter, “rail pressure”) detected by the pressure sensor 3a is within a predetermined range. Fluctuations in rail pressure change the injection rate. Therefore, the range of rail pressure for performing correlation detection is predetermined. If the rail pressure is out of the specified range, the process proceeds to S112 to end the correlation detection process. On the other hand, if the rail pressure is within the specified range, the process proceeds to S107. The regulation range is a pressure range defined in advance as a range in which correlation can be detected.

In S108, it is determined whether or not the rotation of the crankshaft of the engine 2 is stable. For example, if the rotation speed of the crankshaft is not stable due to disturbance of the alternator, the compressor of the air conditioner, or the like, the inclination of the increase in the injection rate cannot be correctly determined. In order to avoid such a situation, when the engine 2 is driving the alternator, the compressor, and the like and it is determined that the rotation of the crankshaft is not stable, the process proceeds to S112 and the correlation detection process is terminated. On the other hand, when it is determined that the load for driving the alternator, the compressor, etc. is not substantially generated in the engine 2 and the rotation of the crankshaft is stable, the process proceeds to S109.

In S109, an injection process for correlation detection is performed, _{a search for a high / low threshold value Th Hi} or a valve opening threshold value Th _{Lo is performed} , and a second drive energy V _Hi or a first drive energy V _Lo is set, and the process proceeds to S110. .. In S110, the detection of the correlation between the drive energy and the slope of the injection rate increase is completed, and it is determined whether or not the update of the _{drive energies V Hi} and V _{Lo is completed.} When it is determined in S110 that the correlation detection is not completed, the update of _{each drive energy VHi and VLo is continued by repeatedly executing the correlation detection process.} On the other hand, when it is determined that the correlation detection is completed, the process proceeds to S111 and the value of the integrated mileage D is cleared. As described above, after resetting the integrated mileage D, the correlation detection process is temporarily terminated.

Next, the details of the detection injection process performed in S109 of the correlation detection process will be described with reference to FIGS. 10 to 13.

In S131 of the detection injection process shown in FIG. 10, it is determined whether or not the _{high / low threshold value Th Hi has been detected.} When it is determined in S131 that the detection of the high / low threshold value Th _Hi has not been completed, the process proceeds to S132 to perform a detection process for detecting the _{high / low threshold value Th Hi (hereinafter, “Th Hi} detection process”). On the other hand, when it is determined in S131 that the high / low threshold value Th _Hi has been detected, the process proceeds to S133, and a detection process for detecting the _{valve opening threshold value Th Lo (hereinafter, “Th Lo} detection process”) is performed.

In _{Th Hi} detection process of S151 shown in FIG. 11, the driving energy _{V h} for correlation detection for searching the height threshold value _{Th Hi} put the drive unit 30, the process proceeds to S152. For the initial value of the drive energy V _h input in S151, for example, the value of the second drive energy V _Hi before the update or the value of the high / low threshold value Th _Hi before the update is used.

In S152, the magnitude of the inclination of the injection rate increase is determined from the fluctuation amount of the rotation speed accompanying the input of the _{drive energy V h, and the process proceeds to S153.} Specifically, when the fluctuation amount of the rotation speed is equivalent to Δr2 (see the short broken line in FIG. 8), it is determined that the slope of the injection rate increase is “large”. On the other hand, when the fluctuation amount of the rotation speed is equivalent to Δr1 (see the long broken line in FIG. 8), it is determined that the slope of the injection rate increase is “small”.

In S153, based on the determination of S152, by adjusting the driving energy _{V h} to be introduced at the next S151, the process proceeds to S154. Specifically, in S153, _{the value obtained by adding ΔE to the drive energy V h} input immediately before is defined as the next drive energy V _h . When it is determined in S152 immediately before that the slope of the injection rate increase is “small” (see the black square in FIG. 13), ΔE is set to a positive value. Therefore, the drive energy V _h is gradually increased. On the other hand, when it is determined in S152 that the slope of the injection rate increase is “large” (see the white square in FIG. 13), ΔE is set to a negative value. Therefore, the drive energy V _h is gradually reduced. By setting the positive and negative values of ΔE as described above, the driving energy V _h is changed little by little and the injection is repeated, and the driving energy V _h is adjusted so as to asymptotically approach the high / low threshold value Th _Hi (see FIG. 13).

_{In S154, the high / low threshold value Th Hi} is detected based on whether or not the change in the slope of the injection rate increase has occurred. If the determination result of the inclination of the injection rate increase in the immediately preceding S152 is the same as the previous determination result, the process returns to the detection injection process (correlation detection process). On the other hand, when the determination result of S152 is different from the previous determination result, that is, when the slope of the injection rate increase changes, it can be seen _{that the drive energy V h} at that time is a high / low threshold value Th _Hi. Therefore, assuming that the high / low threshold value The _Hi is detected, the process proceeds to S155.

In S155, the drive energy V _h input in the immediately preceding S 151 is regarded as a high / low threshold value Th _Hi, and the second drive energy V _Hi is set. Specifically, in S155, a value obtained by adding a predetermined constant m to the high / low threshold value Th _Hi is set as the second drive energy V _Hi , and the process returns to the detection injection process (correlation detection process). The constant m is a value that is predetermined by conformity and is a margin that allows for an injection error.

On the other hand, in S171 of the _{Th Lo} detection process shown in FIG. 12, _{the drive energy V l} for correlation detection for searching the _{valve opening threshold Th Lo} is input to the drive unit 30, and the process proceeds to S172. For the initial value of the drive energy V _l input in S171, for example, the value of the first drive energy V _Lo before the update or the value of the valve opening threshold Th _Lo before the update is used.

In S172, it is determined whether or not fuel injection has been performed in the low-speed valve opening mode from the amount of fluctuation in the rotation speed accompanying the input of the _{drive energy V l, and the process proceeds to S173.} Specifically, when the fluctuation amount of the rotation speed is equivalent to Δr1 (see the long dashed line in FIG. 8), it is determined that the fuel injection has been performed, and when there is no fluctuation amount of the rotation speed, no injection is performed. Judged as

In S173, based on the determination in S172, the drive energy V _l to be input in the next S171 is adjusted, and the process proceeds to S174. Specifically, in S173, _{the value obtained by adding ΔE to the drive energy V l} input immediately before is defined as the next drive energy V _l . When it is determined in S172 immediately before that there is no injection (see the black circle in FIG. 13), ΔE is set to a positive value. Therefore, the drive energy V _l is gradually increased. On the other hand, when it is determined in S172 that the fuel injection has been performed (see the white circle in FIG. 13), ΔE is set to a negative value. Therefore, the drive energy V _l is gradually reduced. By setting the positive and negative values of ΔE as described above, the driving energy V _l is changed little by little and the injection is repeated, and the driving energy V _l is adjusted so as to asymptotically approach the valve opening threshold Th _Lo (see FIG. 13).

_{In S174, the valve opening threshold Th Lo} is detected based on whether or not the switching of the presence or absence of fuel injection has occurred. If the determination result of the presence or absence of fuel injection in S172 immediately before is the same as the previous determination result, the process returns to the detection injection process (correlation detection process). On the other hand, when the determination result of S172 is different from the previous determination result, it is known that the drive energy V _l at that time is the valve opening threshold Th _Lo . Therefore, assuming that the valve opening threshold Th _Lo is detected, the process proceeds to S175.

In S175, the drive energy V _l input in the immediately preceding S171 is regarded as the valve opening threshold Th _Lo, and the first drive energy V _Lo is set. Specifically, in S175, the average value of the _{valve opening threshold Th Lo} and _{the high / low threshold Th Hi detected in the Th Hi} detection process (see FIG. 11) _{is set as the first drive energy V Lo} , and the detection injection process (see FIG. 11). Correlation detection processing) returns.

Here, when the above-mentioned correlation detection conditions (S103 to S108) are not satisfied due to the restart of the vehicle running during the correlation detection, the correlation before the interruption is satisfied the next time the correlation detection condition is satisfied. Correlation detection is restarted from the driving energies V _h and V _{l during detection.} The fuel injection for running during the period in which the correlation detection is interrupted is carried out by inputting the _{drive energies V Hi} and V _{Lo used before the start of the correlation detection.} Further, if the engine 2 is provided with a plurality of fuel injection devices 10, the processes of setting _{the driving energies V Hi} and V _{Lo for traveling of each fuel injection device 10 are sequentially executed.}

Next, the details of the correlation detection process performed as the initial learning will be described with reference to the flowchart shown in FIG. The correlation detection process of FIG. 14 is performed, for example, when the vehicle is shipped or when the fuel injection device 10 is replaced. The control device 100 starts the correlation detection process based on, for example, an execution command for initial learning input from the outside. The control device 100 intentionally adjusts the state of the engine 2 to a state suitable for detecting the high / low threshold value Th _Hi and the valve opening threshold value Th _{Lo, and then performs the initial learning.}

In S191, the state of the engine is normalized, and the process proceeds to S192. In S192, the cooling water temperature is adjusted within the specified range, and the process proceeds to S193. In S193, the clutch of the drive system is opened so that the fluctuation of the rotation speed due to the single injection is easily reflected, and the process proceeds to S194. In S194, the fuel injection is cut, a non-injection deceleration state is created, and the process proceeds to S195. In S195, the rail pressure is adjusted within the specified range, and the process proceeds to S196. In S196, the rotation of the crankshaft is stabilized, and the process proceeds to S197. In S197, the detection injection process (see FIGS. 10 to 12) is performed, and the correlation detection process for initial setting is completed.

In the present embodiment described so far, attention is paid to the fact that if the slope of the increase in the injection rate is different, the mode of fluctuation occurring in the rotation speed of the engine 2 is also different. The correlation with the inclination is determined from the amount of fluctuation in the rotation speed of the engine 2. Then, based on the determination result of the correlation between the drive energy and the slope of the injection rate increase, the first drive energy V _Lo and the second drive energy V _{Hi are set as the setting values of the drive energy for realizing the slope of each injection rate increase.} Is set.

As described above, if the drive energy for correlation detection is actually input to the drive unit 30 and each set value is set based on the determination result, the drive energies V _Lo and V _Hi will be the current fuel injection. It can be a value that correctly realizes the desired inclination of the injection rate increase in the device 10. Therefore, it is possible to avoid a situation in which fuel injection is performed with an erroneous inclination of the injection rate increase due to a machine difference, aged change, or the like.

In addition, the injection determination unit 73 of the present embodiment determines whether the inclination of the injection rate increase is for high-speed valve opening or low-speed valve opening, and is a high-low threshold value Th that is a boundary between the high-speed valve opening mode and the low-speed valve opening mode. Search for _Hi. If the high / low threshold value Th _Hi is determined in this way, the second drive energy V _Hi input in the high-speed valve opening mode can be a suitable value for causing the inclination of the injection rate increase required in the high-speed valve opening mode. ..

Further, the injection determination unit 73 of the present embodiment further searches for the _{valve opening threshold Th Lo,} which is a boundary between the fuel injection in the low-speed valve opening mode and the non-injection state, based on the determination of the presence or absence of fuel injection. If the valve opening threshold Th _Lo is determined together with the high and low threshold Th _Hi in this way, the first drive energy V _Lo input in the low speed valve opening mode causes the inclination of the injection rate increase required in the low speed valve opening mode. It can be a suitable value for.

Further, in the detection injection process of the present embodiment, the drive control unit 72 _{stepwise sets the detection drive energies V h} and V _l closer to the _{high and low threshold values Th Hi} and the valve opening threshold value Th _Lo , respectively. Change. According to the above processing, the injection determination unit 73 can search for each true value of the high / _{low threshold value Th Hi} and the valve opening threshold value Th _{Lo with high accuracy.} Therefore, the first drive energy V _Lo and the second drive energy V _Hi are values that allow the individual fuel injection devices 10 to perform fuel injection with a correct inclination of the injection rate increase.

In addition, the present embodiment, the second drive energy V _Hi for fast opening valve is set based on the height threshold Th _Hi. Further, the first drive energy V _Lo for low-speed valve opening is set based on both the high-low threshold Th _Hi and the valve opening threshold Th _Lo. As described above, if the drive energies V _Hi and V _Lo used in each valve opening mode are set based on the threshold values Th _Hi and Th _Lo , the drive energies V _Hi and V _Lo are set to the threshold values Th _Hi. , Th _Lo can be a value with a sufficient margin. Therefore, even if an error in the search and a secular change occur, the control device 100 can make the fuel injection device 10 continuously perform fuel injection at an intentional inclination of the injection rate increase.

Further, in the correlation detection process of the present embodiment, the search for the high / low threshold value Th _Hi is prioritized over the search for _{the valve opening threshold value Th Lo.} As described above, the second drive energy V _Hi for fast opening valve, even before placing the valve opening threshold value Th _Lo, if the even determined height threshold Th _Hi, can be set. Therefore, if the priority is searched high and low threshold Th _Hi, allowing rapid updates of the second drive energy V _Hi.

Further, in the detection injection process in the present embodiment, the magnitude of the driving energy is increased or decreased while the length of the injection period is maintained substantially constant. As described above, according to the process of aligning the injection periods as the condition of the drive signal, the fluctuation of the inclination of the injection rate increase is likely to be directly reflected in the fluctuation of the rotation speed of the engine 2. As a result, the injection determination unit 73 can accurately determine the correlation between the driving energy and the inclination of the injection rate increase.

In addition, in the present embodiment, the correlation detection process as the initial learning is performed, and the initial values of the _{drive energies V Hi} and V _{Lo used in each valve opening mode are set based on the determination result.} According to the implementation of the initial learning as described above, the control device 100 can execute the fuel injection of the fuel injection device 10 with the intentional inclination of the injection rate increase even immediately after shipment and immediately after replacement.

Further, in the present embodiment, the execution timing of the correlation detection process in consideration of the deterioration of the fuel injection device 10 is controlled by the timing determination unit 75, and is set at the time when the vehicle has traveled a certain distance or more since the previous correlation detection. Therefore, the valve opening threshold Th _Lo and the high / low threshold Th _Hi are searched for at an appropriate timing, and the first drive energy V _Lo and the second drive energy V _Hi are updated. As a result, the control device 100 can continuously execute the fuel injection of the fuel injection device 10 with the intentional inclination of the injection rate increase.

Further, the correlation detection process in consideration of the deterioration of the fuel injection device 10 is performed during use by the user after shipment, unlike the initial learning. Therefore, the correlation detection process needs to be performed so as not to be recognized by the user. In addition, since it is a special control, it is desirable to minimize the effect on driving. Further, in order to discriminate the slope of the increase in the injection rate, it is desirable that the amount of variation in the number of revolutions generated with respect to a specific fuel injection is constant. Therefore, the correlation detection process is performed when a plurality of correlation detection conditions are satisfied.

Specifically, in the present embodiment, the correlation between the driving energy and the inclination of the injection rate increase is detected in the non-injection control state and the clutch open state, and the valve opening threshold Th _Lo and the high / low threshold Th _Hi are searched. According to the setting of the correlation detection condition as described above, the influence on the rotation speed due to the increase / decrease in the running resistance due to the road surface condition, the influence on the rotation speed due to the fuel injection for running, and the like can be substantially eliminated. .. Therefore, the injection determination unit 73 can accurately determine the correlation between the drive energy and the inclination of the injection rate increase. In the above embodiment, the engine 2 corresponds to the "engine" and the control device 100 corresponds to the "fuel injection control device".

(Other embodiments)
Although one embodiment of the present disclosure has been described above, the present disclosure is not construed as being limited to the above embodiment, and is applied to various embodiments and combinations without departing from the gist of the present disclosure. be able to.

The specific configuration of the valve mechanism provided in the fuel injection device can be changed as appropriate. For example, in the modified example shown in FIG. 15, the hydraulically actuated valve body 62 separates the control chamber 27 and the valve chamber 28. In this modification as well, the _{drive unit 30 to which the first drive energy V Lo} is input leaves the first control valve body 61 away from the seat, while the second control valve body 63 remains seated on the hydraulically actuated valve body 62. And. In the above first throttle state, the fuel flow in the low-speed communication passage 62a is permitted, while the fuel flow in the high-speed communication passage 62b is blocked. As a result, the fuel flow rate flowing out from the control chamber 27 to the valve chamber 28 and the low pressure chamber 24 is limited only by the first orifice 66a, so that the inclination of the injection rate increase becomes small.

In contrast, the second drive energy V _Hi driver 30, which is charged are both thereby unseating the first control valve 61 and the second control valve body 63. In the above second throttle state, the fuel of the control chamber 27 can flow into the high-speed communication passage 62b, and both the first orifice 66a and the second orifice 66b use the fuel of the control chamber 27 in the valve chamber 28 and the low pressure chamber. Distribute to 24. As a result, the inclination of the injection rate increase becomes large.

If the correlation detection process of the present disclosure is applied to the control device that controls the fuel injection device as described above, the correlation between the drive energy input to the drive unit and the number of paths in the communication state can be correctly learned. Then, by resetting the drive energy that realizes the inclination of each injection rate increase based on the threshold value of the drive energy that switches the number of paths, it is possible to prevent fuel injection at an unintended inclination of the fuel injection rate increase. It becomes.

Further, if the fuel injection device has a configuration in which the throttle state changes depending on the magnitude of the drive energy input to one drive unit, the number of continuous passages flowing out from the control chamber 27 is not switched as described above. May be good. For example, in the valve mechanism, a low-speed communication passage provided with a small orifice and a high-speed communication passage provided with a large orifice are selectively (exclusively) switched by increasing or decreasing the driving energy input to one drive unit. It may be configured to be. Further, the valve mechanism is provided with a small orifice and a large orifice in series in one communication passage, and the small orifice is separated from the communication passage by switching the increase of the drive energy input to the drive unit. May be good. Further, the throttle state in the valve mechanism may be further switched in multiple stages.

In the above embodiment, the clutch open state is set as the correlation detection condition. The clutch that is disengaged during the correlation detection may be provided anywhere in the drive system. The torque converter of the automatic transmission may be in the open state (lockup release state). Further, the clutch or brake in the main body of the automatic transmission may be in the open state (neutral state).

Further, in the above embodiment, the correlation detection process is performed in the deceleration-free state. However, for example, if the influence of fuel injection for maintaining the idle speed can be eliminated by calculation, the correlation detection process may be performed at idle.

The correlation detection process of the above embodiment was started by turning on the ignition. However, the correlation detection process may be started, for example, when the deceleration non-injection state is reached. In such a form, the step of determining the fuel cut in the correlation detection process may be omitted as appropriate.

In the above embodiment, for example, the drive energy values (V _Hi , V _Lo ) for running before the update are used as _{the initial values of the drive energies V h} and V _{l for correlation detection.} Here, according to the deterioration of the drive unit, the high / low threshold value Th _Hi and the valve opening threshold value Th _Lo gradually increase. Therefore, assuming the secular change of the high and low thresholds Th _Hi and the valve opening threshold Th _{Lo , the initial values of the driving energies V h} and V _l for correlation detection are higher than those of the previous high _{and low thresholds Th Hi} and the valve opening threshold Th _Lo. Set to a slightly higher value. Based on the above, it may be possible to speed up the search for each of the threshold values Th _Hi and Th _Lo.

In the above embodiment, both the _{high and low thresholds Th Hi} and the valve opening threshold Th _Lo are detected as the correlation between the driving energy and the slope of the increase in the injection rate. However, for example, the detected value may be only _{the high / low threshold value Th Hi.} Further, the method of calculating the set value of the driving energy using the high / low threshold value Th _Hi and the valve opening threshold value Th _{Lo may be appropriately changed.}

In the above embodiment, a piezo actuator having a laminated body of piezoelectric elements has been adopted as a drive unit. However, the drive unit may have a configuration having, for example, a magnetic actuator or the like.

In the above embodiment, an example in which the correlation detection process according to the present disclosure is applied to a control device that controls a fuel injection device that injects light oil as fuel has been described. However, the implementation of the above correlation detection process is also effective in a control device that controls a fuel injection device that injects a fuel other than light oil, for example, a liquefied gas fuel such as dimethyl ether.

1 Fuel injection control system, 2 Engine (engine), 2b Combustion chamber, 10 Fuel injection device, 29 Injection hole, 30 Drive unit, 72 Drive control unit, 73 Injection judgment unit, 74 Energy setting unit, 75 Timing determination unit, 100 Control device (fuel injection control device), Th _Hi high / low threshold, Th _Lo valve opening threshold

Claims (11)

Fuel is injected from the injection hole (29) toward the combustion chamber (2b) of the engine (2), and the inclination of the injection rate increase in the fuel injection can be switched by the drive energy input to the drive unit (30). A fuel injection control device that controls the device (10).
A drive control unit (72) that controls the input of drive energy to the drive unit, and
The injection determination unit (73) determines the correlation between the drive energy input by the drive control unit and the slope of the injection rate increase caused by the input of the drive energy from the fluctuation amount of the engine speed.
A fuel injection control device including an energy setting unit (74) that sets a set value of a drive energy that realizes an inclination of each injection rate increase that can be switched by the fuel injection device based on a determination result of the injection determination unit. The injection determination unit
Based on the fluctuation amount of the engine speed, at least it is determined whether the inclination of the injection rate increase is for high-speed valve opening or low-speed valve opening.
The fuel injection control device according to claim 1 for searching a height threshold (Th _Hi) indicating the boundary between the driving energy for the slow opening of the injection hole and the driving energy for fast opening of the injection hole. The fuel injection control device according to claim 2, wherein the drive control unit gradually changes the drive energy input to the drive unit so as to approach the high / low threshold value in order to set the set value. The injection determination unit
Based on the fluctuation amount of the engine speed, at least it is determined whether or not the fuel injection by the fuel injection device has been performed.
The fuel injection control device according to claim 2 or 3, further searching _{for a valve opening threshold value (Th Lo} ) indicating a boundary between a driving energy that does not open the injection hole and a driving energy that opens the injection hole at a low speed. The energy setting unit
The set value of the drive energy that realizes the inclination of the injection rate increase for high-speed valve opening is set based on the high / low threshold value.
The fuel injection control device according to claim 4, wherein the set value of the driving energy for realizing the inclination of the injection rate increase for low-speed valve opening is set based on both the high-low threshold value and the valve opening threshold value. The fuel injection control device according to claim 4 or 5, wherein the injection determination unit prioritizes the search for the high / low threshold value over the search for the valve opening threshold value. The fuel injection control device according to any one of claims 1 to 6, wherein the drive control unit fluctuates the drive energy while maintaining the length of the injection period for inputting the drive energy into the drive unit. The injection determination unit determines the correlation between the driving energy and the inclination of the injection rate increase as initial learning of the fuel injection device.
The item according to any one of claims 1 to 7, wherein the energy setting unit sets an initial value of the driving energy that realizes the inclination of each injection rate increase as the set value based on the determination result by the initial learning. Fuel injection control device. A timing determination unit (75) for determining the update timing of the set value is further provided.
The injection determination unit determines a change in the correlation between the drive energy and the inclination of the injection rate increase at the timing determined by the timing determination unit.
The fuel injection control device according to any one of claims 1 to 8, wherein the energy setting unit sets the set value based on the determination result of the injection determination unit. The injection determination unit is in a non-injection control state in which there is no fuel injection command for driving the vehicle equipped with the engine, and the clutch provided between the drive wheels of the vehicle and the engine is released. The fuel injection control device according to any one of claims 1 to 9, wherein the fuel injection control device determines the correlation between the driving energy and the inclination of the injection rate increase in this state. Fuel is injected from the injection hole (29) toward the combustion chamber (2b) of the engine (2), and the slope of the increase in the injection rate in the fuel injection can be switched by the drive energy input to the drive unit (30). Device (10) and
A drive control unit (72) that controls the input of drive energy to the drive unit,
The injection determination unit (73) determines the correlation between the drive energy input by the drive control unit and the slope of the injection rate increase caused by the input of the drive energy from the amount of fluctuation in the rotation speed of the engine.
The fuel injection device has an energy setting unit (74) that sets a set value of a drive energy that realizes an inclination of each injection rate increase that can be switched by the fuel injection device based on the determination result of the injection determination unit. A fuel injection control system including a fuel injection control device (100) for controlling the device.

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