WO2011078153A1 - Device for determining abnormality in fuel injection valve, and method for determining abnormality in fuel injection valve - Google Patents

Abstract

Provided is an abnormality determination device for determining the presence of abnormalities in a plurality of fuel injection valves. The abnormality determination device is provided with a pressure sensor, and an electronic control unit. The electronic control unit determines the presence of abnormalities in a fuel injection valve on the basis of the changes in the condition of the fuel, which is detected by means of the pressure sensor. The electronic control unit determines whether or not the fuel injection valve which injected fuel remains open on the basis of the changes in the condition of the fuel pressure at the fuel injection valve which injected fuel, and the changes in the condition of the fuel pressure at the fuel injection valve which did not inject fuel.

Description

Fuel injection valve abnormality determination device and fuel injection valve abnormality determination method

The present invention relates to an abnormality determination device for a fuel injection valve, and more particularly to an abnormality determination device and an abnormality determination method for a fuel injection valve that determine the occurrence of open sticking in a fuel injection valve provided for each of a plurality of cylinders of an internal combustion engine.

As a method of determining the occurrence of open sticking that causes the fuel injection valve to open and not close, monitor the change in rail pressure, which is the fuel pressure in the common rail and delivery pipe, and the change in engine speed, There is known a method of detecting that the fuel is continuously injected against the valve closing command based on these change modes and determining that the injection valve is stuck open.

However, in such a method, since the occurrence of open adhesion cannot be determined after the occurrence of open adhesion until the rail pressure and the engine rotational speed fluctuate due to the influence thereof, it takes time to determine the occurrence of open adhesion. It will take. In addition, it is difficult to determine which of the fuel injection valves provided for each of the plurality of cylinders is open and stuck.

Therefore, in the fuel injection valve abnormality determination device described in Patent Document 1, a pressure sensor for detecting the pressure of the fuel supplied to each of the plurality of cylinders is provided for each of the injection valves. Provided. And the change of the fuel pressure accompanying injection is monitored for every injection valve, and abnormality of each injection valve is judged based on the change mode.

According to such a configuration, small fluctuations in fuel pressure accompanying opening and closing of the injection valves can be quickly detected by the pressure sensors provided in the respective injection valves. Therefore, for example, when it is detected that the fuel pressure in the injection valve has not increased even though the fuel pressure should increase with the end of fuel injection, It can be determined that open sticking has occurred. That is, compared with the case where the occurrence of open sticking is determined based on changes in rail pressure or engine rotational speed, the occurrence of open sticking can be quickly determined, and any injection valve has an open sticking. It becomes possible to easily determine whether or not there is.

JP 2009-85164 A

However, when it is detected that the fuel pressure in the injection valve has not increased despite the fact that fuel injection has been completed as described above, the occurrence of open sticking is immediately determined based on this. In such a case, there is a possibility that an erroneous determination that open sticking has occurred due to superimposition of noise on the detected value of the fuel pressure or the like may occur. In addition, in order to suppress the occurrence of such an erroneous determination, by changing the fuel pressure determination threshold value or the like to make it difficult to determine the open sticking, the open sticking actually occurs although the open sticking has occurred. The sticking judgment is not made.

An object of the present invention is to provide a fuel injection valve abnormality determination device and a fuel injection valve abnormality determination method capable of quickly and accurately determining the occurrence of open sticking while suppressing the occurrence of erroneous determination. is there.

In order to achieve the above object, according to the first aspect of the present invention, an abnormality determination device for determining abnormality of a plurality of fuel injection valves is provided. The abnormality determination device includes a pressure sensor and a determination unit. The plurality of fuel injection valves are respectively provided for the plurality of cylinders of the internal combustion engine. Pressure sensors are respectively provided in the fuel injection valves. The pressure sensor detects the pressure of the fuel supplied to the corresponding fuel injection valve. The determination unit determines abnormality of the fuel injection valve based on a fuel change mode detected by the pressure sensor. The determination unit causes an open sticking to occur in the fuel injection valve that injects the fuel based on the fuel pressure change mode in the fuel injection valve that injected the fuel and the fuel pressure change mode in the fuel injection valve that did not inject the fuel. Determine what happened.

According to a second aspect of the present invention, a method for determining an abnormality in a plurality of fuel injection valves is provided. The plurality of fuel injection valves are respectively provided for the plurality of cylinders of the internal combustion engine. The method includes detecting a pressure of fuel supplied to a corresponding fuel injection valve by a pressure sensor provided in each of the fuel injection valves, and detecting a pressure sensor provided in the fuel injection valve that injected the fuel. And confirming that there is no increase in pressure due to the closing of the fuel injection valve in the fuel pressure change mode, and the fuel pressure detected by the pressure sensor provided in the fuel injection valve that did not inject fuel. A step of confirming that there is no pressure increase due to the closing of the fuel injection valve that injected the fuel in the change mode, a change mode of the fuel pressure in the fuel injection valve that injected the fuel, and a fuel injection valve that did not inject the fuel The fuel was injected on the basis of the fact that it was confirmed that there was no pressure increase due to the closing of the fuel injection valve that injected the fuel in both aspects of the fuel pressure change in And a step of determining that the open sticking to fuel injection valve occurs.

The schematic diagram which shows schematic structure of the fuel-injection apparatus concerning one Embodiment of this invention. Sectional drawing of the fuel injection valve of the fuel-injection apparatus of FIG. The time chart which shows the relationship between the change aspect of the fuel pressure in the fuel injection valve which injected the fuel, and the change aspect of the fuel pressure in the other fuel injection valve which did not inject fuel. The flowchart which shows the flow of a series of processes of the open sticking determination process concerning the fuel-injection apparatus of FIG.

Hereinafter, an embodiment in which a fuel injection valve abnormality determination device according to the present invention is applied to a fuel injection device of a diesel engine will be described with reference to FIGS.
As shown in FIG. 1, the fuel injection device according to this embodiment includes a total of four fuel injection valves 20, one for each cylinder of the diesel engine. Each fuel injection valve 20 is connected to a common rail 34 via a branch passage 31a.

The common rail 34 is connected to the fuel tank 32 through the supply passage 31b, and a fuel pump 33 is provided in the middle of the supply passage 31b. As a result, the fuel pumped by the fuel pump 33 is stored in the common rail 34 and supplied to each fuel injection valve 20 via the common rail 34 and the branch passage 31a.

Further, a return passage 35 is connected to each fuel injection valve 20. The return passage 35 is connected to the fuel tank 32, and a part of the fuel not injected from the fuel injection valve 20 is returned to the fuel tank 32 through the return passage 35.

The fuel injection device according to the present embodiment configured as described above is controlled by an electronic control unit 40 (determination unit) that comprehensively controls the diesel engine. The electronic control unit 40 detects a water temperature sensor 41 for detecting the engine cooling water temperature THW, a rotation speed sensor 42 for detecting the engine rotation speed NE, an intake air amount sensor 43 for detecting the intake air amount GA of the diesel engine, and a vehicle speed SPD. A vehicle speed sensor 44 and an accelerator pedal depression amount sensor (accelerator operation amount sensor) 45 for detecting an accelerator pedal depression amount (accelerator operation amount) ACCP by the driver are connected.

Further, as shown in FIG. 1, each fuel injection valve 20 is provided with a pressure sensor 46 for detecting a fuel pressure PQ, which is the pressure of the fuel supplied to the fuel injection valve 20, and an electronic control unit. This pressure sensor 46 is also connected to 40.

The electronic control unit 40 takes in the signals output from these various sensors 41 to 46 and performs various calculations based on the signals. And according to the calculation result, the electronic control unit 40 performs fuel injection control.

For example, the electronic control unit 40 selects an injection pattern based on the intake air amount GA, the engine rotational speed NE, the fuel pressure PQ, the accelerator operation amount ACCP, and the like, and the injection timing and the injection amount conform to the injection pattern. Thus, the target value of the opening / closing timing of each fuel injection valve 20 is calculated. Then, the electronic control unit 40 outputs a valve opening command and a valve closing command as injection commands to each fuel injection valve 20 so as to correspond to these target values, and opens and closes each fuel injection valve 20 separately. As a result, an amount of fuel commensurate with the engine operating state is injected from each fuel injection valve 20 with an injection pattern suitable for the engine operating state at that time.

In the fuel injection device according to the present embodiment, a plurality of injection patterns that combine main injection, pilot injection, after-injection, etc. are preset and stored in the electronic control unit 40. An injection pattern suitable for the engine operating state at that time is selected from previously stored injection patterns.

Next, the internal structure of the fuel injection valve 20 and the mounting position of the pressure sensor 46 according to this embodiment will be described with reference to FIG. FIG. 2 is a cross-sectional view of the fuel injection valve 20 according to the present embodiment.

2, a housing space 21 a for housing the needle valve 22 is formed inside the housing 21 of the fuel injection valve 20. In addition, a nozzle hole 21 b that penetrates the housing 21 and communicates with the outside is provided at the tip of the housing 21.

In the accommodating space 21a, the needle valve 22 is accommodated so as to be slidable in the axial direction thereof, that is, in the vertical direction in FIG. The accommodation space 21a is connected to an introduction passage 21c communicating with a branch passage 31a connected to the common rail 34. Fuel supplied from the common rail 34 is introduced into the accommodation space 21a through the introduction passage 21c. The As shown in the upper side of FIG. 2, the pressure sensor 46 is provided in the upper part of the fuel injection valve 20, and detects the pressure of the fuel in the introduction passage 21c as the fuel pressure PQ.

As shown in FIG. 2, the needle valve 22 is always urged downward by the spring 23 in FIG. When the tip of the needle valve 22 is seated on the inner peripheral surface of the tip of the housing 21 as shown in FIG. 2, the introduction of fuel from the accommodation space 21a to the nozzle hole 21b is stopped, The injection is stopped.

A back pressure chamber 21d is provided in the rear end portion of the needle valve 22 in the housing 21. As shown in FIG. 2, the back pressure chamber 21d communicates with the accommodation space 21a via the control chamber 21e.

The control chamber 21e is provided with a discharge hole 21f communicating with a discharge passage 21g connected to the return passage 35, and a control valve 24 for closing the discharge hole 21f is accommodated in the control chamber 21e. The control valve 24 is always urged by the spring 25 in the direction of closing the discharge hole 21f.

A piezoelectric element actuator 26 in which piezoelectric elements that expand and contract due to the piezoelectric effect are stacked is disposed at a position facing the control valve 24 across the discharge hole 21f in the housing 21. The distal end portion 26a of the piezo element actuator 26 is in contact with the control valve 24 inside the discharge hole 21f. The piezo element actuator 26 is an actuator that expands when a charge (not shown) is charged, and contracts when the charge stored in the drive circuit is discharged. The drive current controlled by the electronic control unit 40 It expands and contracts according to.

When no electric charge is stored in the drive circuit, the piezo element actuator 26 is contracted, and the control valve 24 is held at a position where the discharge hole 21f is closed by the urging force of the spring 25 as shown in FIG. . Thereby, the fuel introduced through the introduction passage 21c is filled in the accommodation space 21a, the control chamber 21e, and the back pressure chamber 21d, and the pressure of the fuel acting on the portion of the needle valve 22 on the accommodation space 21a side, The pressure of the fuel acting on the portion of the needle valve 22 on the back pressure chamber 21d side is kept high.

At this time, there is no significant difference between the pressure of the fuel acting on the portion of the needle valve 22 on the accommodation space 21a side and the pressure of the fuel acting on the portion of the needle valve 22 on the back pressure chamber 21d side. The needle valve 22 is held in a state of being seated on the housing 21 by the urging force of the spring 23.

When fuel is injected from the fuel injection valve 20, the electronic control unit 40 operates the drive current so as to charge the drive circuit of the piezo element actuator 26 as a valve opening command. As a result, the piezo element actuator 26 extends, and the control valve 24 pressed by the tip portion 26a of the piezo element actuator 26 is displaced to the valve opening side against the biasing force of the spring 25, and is controlled via the discharge hole 21f. The chamber 21e communicates with the discharge passage 21g. When the control chamber 21e and the discharge passage 21g communicate with each other in this way, the fuel in the back pressure chamber 21d communicating with the control chamber 21e is discharged together with the fuel in the control chamber 21e to the return passage 35 through the discharge passage 21g. The pressure of the fuel 21d decreases. When the fuel pressure in the back pressure chamber 21d decreases in this way, the balance of the fuel pressure acting on the needle valve 22 is lost, and the needle valve 22 increases the volume of the back pressure chamber 21d against the biasing force of the spring 23. In the decreasing direction, that is, upward in FIG. As the needle valve 22 is displaced in this way, the fuel flows from the accommodation space 21a into the nozzle hole 21b through the gap formed between the tip of the needle valve 22 and the inner peripheral surface of the tip of the housing 21. Is injected into the cylinder.

On the other hand, when the fuel injection is stopped, the electronic control unit 40 operates the drive current so as to discharge the electric charge from the drive circuit of the piezo element actuator 26 as a valve closing command. As a result, the piezo element actuator 26 contracts, the control valve 24 pressed by the tip portion 26 a of the piezo element actuator 26 is displaced to the valve closing side by the urging force of the spring 25, and the discharge hole 21 f is closed by the control valve 24. Is done. By closing the discharge hole 21f in this way, the discharge of fuel from the control chamber 21e and the back pressure chamber 21d to the return passage 35 is stopped, the fuel pressure in the back pressure chamber 21d rises, and the needle valve 22 The chamber 21d is displaced in the direction of increasing the volume, that is, downward in FIG. Thus, the needle valve 22 is displaced, and the tip of the needle valve 22 is seated on the inner peripheral surface of the tip of the housing 21, whereby the introduction of fuel from the accommodation space 21a to the injection hole 21b is stopped and fuel injection is stopped. It will be stopped.

Next, how the fuel pressure PQ is detected by the pressure sensor 46 provided in each fuel injection valve 20 will be described with reference to FIG. FIG. 3 is a time chart showing a relationship between a change mode of the fuel pressure PQ in the fuel injection valve 20 that has injected the fuel and a change mode of the fuel pressure PQ in the other fuel injection valves 20 that have not injected the fuel. .

When an injection command is issued to one of the four fuel injection valves 20 through the fuel injection control, and the drive current is charged and discharged as shown in the upper part of FIG. 3, the injection is performed as described above. The needle valve 22 of the commanded fuel injection valve 20 is driven, and the fuel injection valve 20 is opened and closed.

When the fuel injection valve 20 is opened, fuel is injected from the fuel injection valve 20, and the fuel pressure PQ detected by the pressure sensor 46 provided in the fuel injection valve 20 that injected the fuel is shown in the middle part of FIG. As shown in FIG. 4, the fuel amount decreases by the amount of injected fuel (time t1 to t2). When the fuel injection valve 20 is closed, the fuel injection is stopped, so that the decrease in the fuel pressure PQ is stopped, the fuel pressure PQ increases with the supply of fuel from the common rail 34, and the fuel pressure The PQ recovers to a level close to the original level (time t2 to t3).

Note that there is a slight delay from when the drive current is operated until the needle valve 22 of the fuel injection valve 20 is displaced and fuel is injected. Therefore, as shown in FIG. 3, the fuel pressure PQ varies with a slight delay with respect to the change of the drive current. Further, due to the influence of the fluctuation of the fuel pressure PQ accompanying the fuel injection, the fuel pressure PQ immediately after the fuel injection is pulsated as shown in the middle right side of FIG. 3 (from time t3). This pulsation gradually converges to a predetermined value as time passes.

Further, the fuel pressure PQ detected by the pressure sensor 46 provided in the other fuel injection valve 20 where the injection command is not issued through the fuel injection control and the fuel is not injected is the fuel in the common rail 34 by the fuel injection. It fluctuates as shown in the lower part of FIG. Specifically, the fuel pressure PQ detected by the pressure sensor 46 decreases as the fuel pressure in the common rail 34 decreases due to the fuel injection (time t4 to t5). The fuel pressure PQ increases as the fuel pressure in the common rail 34 increases due to the stop of fuel injection, and recovers to a level almost equal to the level before injection (time t5 to t6).

It should be noted that it takes some time until the pressure fluctuation due to the influence is propagated to the other fuel injection valves 20 connected through the common rail 34 after the fuel injection is performed in any one of the fuel injection valves 20. . Therefore, there is a slight delay as shown in FIG. 3 until the fuel pressure PQ in the other fuel injection valves 20 that did not inject fuel changes due to the influence of the fuel injection. Further, even when the fuel pressure PQ is detected by the pressure sensor 46 provided in the other fuel injection valve 20 that is not injecting the fuel, the fuel pressure is immediately after the fuel injection as shown in the lower right side of FIG. Pulsations are generated due to the influence of PQ fluctuation (from time t6).

By the way, when the fuel injection valve 20 does not close while the fuel injection valve 20 is in the open state due to the foreign matter biting into the movable part such as the needle valve 22 as the fuel injection is performed, the valve is closed. Despite the valve command being issued and the drive current being discharged, fuel continues to be injected. Therefore, when such open sticking occurs, the fuel pressure PQ detected by each pressure sensor 46 does not increase toward the level before injection as shown by the two-dot chain line in the middle and lower parts of FIG. It will continue to decline.

Accordingly, when the driving current is discharged and the change in the fuel pressure PQ detected by each pressure sensor 46 does not show a pressure increase due to the valve closing even though the valve closing command is issued, the valve is closed. It is estimated that the fuel injection valve 20 continues to open against the valve command. That is, in this case, it is estimated that the fuel injection valve 20 is stuck open.

In the fuel injection device according to the present embodiment, the fuel injection valve 20 is firmly fixed to the fuel injection valve 20 based on the change mode of the fuel pressure PQ detected by the pressure sensor 46 provided in each fuel injection valve 20 using this relationship. An open sticking determination process is performed to determine that the occurrence has occurred.

Hereinafter, the open adhesion determination process according to the present embodiment will be described with reference to FIG. FIG. 4 is a flowchart showing a flow of a series of processes related to the open adhesion determination process. This open adhesion determination process is repeatedly executed by the electronic control unit 40 every time fuel is injected from each fuel injection valve 20.

The electronic control unit 40 refers to the change mode of the fuel pressure PQ accompanying the fuel injection after the fuel injection is performed, so that each target value can be corrected at the next fuel injection so that each target value can be corrected during the engine operation. The value of the fuel pressure PQ output from the sensor 46 is sequentially stored in the memory. In the open sticking determination processing according to the present embodiment, it is determined whether or not the open sticking has occurred in the fuel injection valve 20 with reference to the change mode of the fuel pressure PQ stored in the memory.

Specifically, when the fuel injection is executed in any one of the fuel injection valves 20, the electronic control unit 40 executes the open sticking determination process shown in FIG. First, in step S100, the change mode of the fuel pressure PQ detected by the pressure sensor 46 provided in the fuel injection valve 20 that injected the fuel is read, and the fuel injection valve 20 is closed to the read change mode of the fuel pressure PQ. Make sure there is no pressure increase associated with the valve.

It should be noted that various methods can be adopted as a method for confirming that the pressure increase associated with the closing of the fuel injection valve 20 is not observed in the change mode of the fuel pressure PQ. In the open adhering determination process according to the present embodiment, it is determined whether or not the fuel pressure PQ of the fuel injection valve 20 that has injected the fuel has become equal to or lower than the first threshold value X after the valve closing command is issued, Based on this determination result, it is confirmed that no pressure increase is observed.

That is, in the open adhering determination process of the present embodiment, the electronic control unit 40 refers to the change mode of the read fuel pressure PQ, and the fuel pressure PQ is equal to or less than the first threshold value X after the valve closing command is issued. It is determined whether or not. When the fuel pressure PQ is not less than or equal to the first threshold value X as shown by the solid line in the middle stage of FIG. 3, the electronic control unit 40 changes the pressure associated with the valve closing to the change mode of the fuel pressure PQ. Determine that there is a rise. On the other hand, when the fuel pressure PQ is equal to or lower than the first threshold value X after the valve closing command is issued as shown by a two-dot chain line in the middle stage of FIG. It is determined that no pressure increase due to the valve closing is observed in the fuel pressure PQ change mode.

The first threshold value X is based on the fact that the fuel pressure PQ is equal to or lower than the first threshold value X after the valve closing command is issued, and the fuel pressure PQ continues to decrease after the valve closing command. It is sufficient that the size is set so that it can be determined. Therefore, in the present embodiment, the first threshold value X is set to the minimum value of the fuel pressure PQ in the fuel injection valve 20 estimated from the valve opening period of the fuel injection valve 20 accompanying fuel injection, that is, in FIG. As shown in the middle, the fuel injection valve 20 is set to a value slightly smaller than the minimum fuel pressure P1, which is the minimum value of the fuel pressure PQ when the fuel injection valve 20 is closed correctly. Note that as the first threshold value X is set to a value closer to the minimum fuel pressure P1, it is easier to determine that no pressure increase is observed.

If it is determined in step S100 that the pressure increase associated with the closing of the fuel pressure PQ in the fuel injection valve 20 that has injected the fuel is not observed (YES in step S100), the process proceeds to step S200. move on.

The electronic control unit 40 then adjusts the fuel pressure PQ detected by the pressure sensor 46 provided in the fuel injection valve 20 that injects the next fuel among the other three fuel injection valves 20 that did not inject the fuel. The change mode is read, and it is confirmed that there is no pressure increase associated with the closing of the fuel injection valve 20 that has injected the fuel in the read change mode of the fuel pressure PQ.

Of the three fuel injectors 20 that did not inject fuel in this way, there is no pressure increase associated with closing the valve by referring to the change mode of the fuel pressure PQ of the fuel injector 20 that injects fuel next. This is because the fuel pressure PQ detected by the pressure sensor 46 is most stable in the fuel injection valve 20 that injects fuel next to the fuel injection valve 20 that injected the fuel. That is, the fuel injection valve 20 that injects fuel next to the fuel injection valve 20 that injected the fuel has the longest time since the last fuel injection among the fuel injection valves 20 provided for each cylinder. This is because the elapsed injection valve. Therefore, in the fuel injection valve 20 that injects fuel next to the fuel injection valve 20 that injected the fuel, the pulsation of the fuel pressure PQ accompanying the previous injection in the fuel injection valve 20 has converged, and the same fuel The detected value of the fuel pressure PQ detected by the pressure sensor 46 provided in the injection valve 20 is stable.

In the open adhering determination process according to the present embodiment, the fuel pressure PQ of the fuel injection valve 20 that injects fuel after the fuel injection valve 20 that injected the fuel is second after the valve closing command is issued. It is determined whether or not the threshold value Y is equal to or less than the threshold value Y, and it is confirmed that no pressure increase is observed based on the determination result.

That is, in the open adhering determination process of the present embodiment, whether or not the fuel pressure PQ is equal to or lower than the second threshold Y after the valve closing command is made with reference to the read change mode of the fuel pressure PQ If the fuel pressure PQ is not less than or equal to the second threshold Y as shown by the solid line in the lower part of FIG. . On the other hand, when the fuel pressure PQ is equal to or lower than the second threshold value Y after the valve closing command is given to the serpentine tube of FIG. It is determined that no pressure increase due to valve closing is observed in the mode.

Note that the second threshold value Y is similar to the first threshold value X, based on the fact that the fuel pressure PQ is equal to or lower than the second threshold value Y after the valve closing command is issued. However, it is only necessary to set the magnitude so that it can be determined that the fuel pressure PQ has continued to decrease. Therefore, in the present embodiment, the second threshold value Y is shown as the minimum value of the fuel pressure PQ estimated from the valve opening period of the fuel injection valve 20 accompanying fuel injection, that is, as shown in the lower part of FIG. The fuel injection valve 20 is set to a value slightly smaller than the minimum fuel pressure P2, which is the minimum value of the fuel pressure PQ when the fuel injection valve 20 is correctly closed. Note that as the second threshold Y is set to a value closer to the minimum fuel pressure P2, it is easier to determine that no pressure increase is observed.

In step S200, when it is determined that the change in the fuel pressure PQ in the fuel injection valve 20 that injects the fuel after the fuel injection valve 20 that injected the fuel does not show an increase in pressure due to the valve closing (step S200). If YES in S200, the process proceeds to step S300.

In step S300, the electronic control unit 40 determines that the fuel injection valve 20 that injected the fuel has been stuck open, and stores the determination result in the memory as an abnormality determination value. When it is determined that the open sticking has occurred in this way, the electronic control unit 40 once ends this process.

On the other hand, when it is determined in step S100 that the pressure increase associated with the valve closing is observed in the change mode of the fuel pressure PQ in the fuel injection valve 20 that injected the fuel (NO in step S100), the electronic control unit In Step 40, Steps S200 and S300 are skipped and the process is temporarily terminated.

Further, in step S100, it is determined that no pressure increase due to valve closing is observed (YES in step S100), but in step S200, it is determined that pressure increase due to valve closing is observed (in step S200). If NO, the electronic control unit 40 skips step S300 and terminates this process once.

That is, in the open adhering determination process according to the present embodiment, the fuel injection valve that injects fuel on the condition that it has been confirmed that no pressure increase due to the valve closing is observed in both step S100 and step S200. It is determined that an open sticking has occurred at 20.

In the fuel injection device according to the present embodiment, the fuel injection valve in which fuel is injected based on the fuel pressure PQ detected by the pressure sensor 46 provided in each fuel injection valve 20 through such an open sticking determination process. Whether or not the open sticking has occurred in 20 is determined.

This embodiment has the following advantages.
(1) Fuel injection in which fuel is injected after referring not only to the change mode of the fuel pressure PQ in the fuel injection valve 20 that has injected fuel, but also to the change mode of the fuel pressure PQ in the fuel injection valve 20 that has not injected fuel It is determined whether or not the open sticking has occurred in the valve 20. Accordingly, since it is comprehensively determined whether or not the open sticking has occurred based on the change in the fuel pressure PQ detected by the separate pressure sensors 46, the open sticking due to the superimposition of noise on the detection value of the pressure sensor 46 or the like. The occurrence of misjudgment is suppressed. Further, the fuel pressure is controlled in order to suppress the erroneous determination of the open sticking, as in the abnormality judging device that judges the open sticking of the fuel injector 20 based only on the change mode of the fuel pressure PQ in the fuel injector 20 that injected the fuel. It is not necessary to make it difficult to make the open adhesion determination by changing the determination threshold of PQ. Therefore, it is possible to promptly determine whether or not open sticking has occurred when open sticking occurs. That is, it is possible to quickly determine the occurrence of open adhesion with high accuracy while suppressing the occurrence of erroneous determination of open adhesion.

(2) Both the change mode of the fuel pressure PQ of the fuel injection valve 20 that injected the fuel and the change mode of the fuel pressure PQ of the fuel injection valve 20 that injects the fuel after the fuel injection valve 20 that injected the fuel. On the condition that no increase in pressure due to the valve closing is confirmed, it is determined that the open sticking has occurred in the fuel injection valve 20 that injected the fuel. Therefore, it is possible to determine the occurrence of open fixation with high accuracy.

(3) Of the four fuel injection valves 20 provided for the cylinder, the fuel is determined based on the change in the fuel pressure PQ of the fuel injection valve 20 that injects fuel next to the fuel injection valve 20 that injected the fuel. It is confirmed that no increase in pressure due to the valve closing is observed in the fuel pressure change mode in the fuel injection valve 20 that did not inject fuel. Therefore, it becomes possible to confirm that there is no pressure increase due to the valve closing without being affected by the pulsation of the fuel pressure PQ accompanying the previous injection in the fuel injection valve 20, and the accuracy of the open sticking determination is improved. Can be improved.

In addition, the said embodiment can also be implemented with the following forms which changed this suitably.
In the above-described embodiment, when it is determined that the open sticking has occurred through the open sticking determination process, the determination result is stored in the memory as an abnormality determination value. On the other hand, when it is determined that the open sticking has occurred, it is also possible to adopt a configuration that notifies the occurrence of the open sticking by turning on a warning lamp or the like.

In the open adhering determination process of the above embodiment, step S100 is first executed by the electronic control unit 40 as the first confirmation unit, and the change mode of the fuel pressure PQ in the fuel injection valve 20 that injected the fuel in step S100. When the determination is made that no increase in pressure due to valve closing is observed, step S200 is executed by the electronic control unit 40 as the second confirmation unit. On the other hand, the order of step S100 and step S200 in the open adhesion determination process may be switched.

That is, in the open sticking determination process, fuel injection is performed by injecting fuel on the condition that it is confirmed that both the first confirmation unit and the second confirmation unit have no pressure increase due to valve closing. It is sufficient that it is determined that the open fixation has occurred in the valve 20, and the processing procedure can be changed as appropriate.

Further, the step S200 may be performed as long as it is confirmed that there is no pressure increase due to the valve closing in the change mode of the fuel pressure PQ of the fuel injection valve 20 that has not injected the fuel. Therefore, step S200 monitors the fuel pressure PQ of the other fuel injection valves 20 that did not inject fuel instead of the fuel injection valve 20 that injects fuel next to the fuel injection valve 20 that injected the fuel, It may be confirmed that no pressure increase is observed in the change mode of the fuel pressure PQ of the fuel injection valve 20 that has injected the fuel.

In addition, step S200 monitors the average value of the fuel pressures PQ of the plurality of fuel injection valves 20 that did not inject fuel, and determines the average value of the fuel pressures PQ of the fuel injection valves 20 that did not inject fuel. You may confirm that the pressure rise accompanying the valve closing of the fuel injection valve 20 which injected the fuel into the change aspect is not seen.

Further, when any one of the fuel injection valves 20 that did not inject fuel does not show a pressure increase due to closing, the fuel pressure of the fuel injection valve 20 that did not inject fuel. It may be determined that the pressure rise due to the valve closing is not observed in PQ.

Further, in all the fuel injection valves 20 that did not inject fuel, when the fuel pressure PQ did not increase due to the valve closing, the fuel pressure PQ of the fuel injection valve 20 that did not inject the fuel was It may be determined that no pressure increase is observed.

In the above embodiment, in step S100 and step S200, as a means for confirming that the pressure increase due to the valve closing is not observed in the change mode of the fuel pressure PQ, the fuel pressure PQ is changed to the first after the valve closing command is issued. The example which employ | adopted the structure which determines whether it became below 1 threshold value X or 2nd threshold value Y was shown. On the other hand, the specific means for confirming that the fuel pressure PQ does not increase in pressure due to the valve closing can be appropriately changed.

As another method for confirming that the fuel pressure PQ does not increase in pressure due to the closing of the fuel injection valve 20 in the change mode of the fuel pressure PQ, for example, the differential value of the fuel pressure PQ is calculated and the differential value is positive. A configuration can be adopted in which it is determined that no pressure increase due to valve closing is observed based on the fact that the value is not reached. Further, it is also possible to adopt a configuration for determining that no pressure increase due to valve closing is observed when the fuel pressure PQ does not exceed a predetermined threshold before a predetermined period elapses from the valve closing command.

In the above-described embodiment, the configuration in which the pressure sensor 46 is provided on the upper portion of the fuel injection valve 20 has been exemplified. However, the configuration is such that the pressure of the fuel supplied to each fuel injection valve 20 can be detected individually. For example, the position of the pressure sensor 46 can be changed as appropriate.

In the above embodiment, in the fuel injection device employing the piezo type fuel injection valve 20 including the piezo element actuator 26, the configuration for determining whether the fuel injection valve 20 is stuck open is exemplified. In contrast, the present invention is not limited to a piezo-type fuel injection valve, and instead of the piezo-type fuel injection valve 20, a solenoid-type fuel injection valve driven by a solenoid coil is employed. The present invention can also be applied to existing fuel injection devices.

In the above embodiment, the configuration in which the electronic control unit 40 performs the open sticking determination process is adopted, and the configuration in which the fuel injection device has the function as the abnormality determination device of the present invention is exemplified. On the other hand, an electronic control device for executing the open sticking determination process is newly provided separately from the electronic control unit 40, and the electronic control device and the pressure sensor 46 are applied to the present invention separately from the fuel injection device. You may make it comprise the abnormality determination apparatus of a fuel injection valve.

Not only a diesel engine having four cylinders, but also a diesel engine having two cylinders, a diesel engine having three cylinders, or a diesel engine having five or more cylinders, the abnormality determination of the fuel injection valve according to the present invention The device can be applied.

In the above embodiment, the fuel injection valve abnormality determination device according to the present invention is applied to a diesel engine fuel injection device. However, the fuel injection valve abnormality determination device according to the present invention is a diesel engine. However, the present invention can be applied to gasoline engines and natural gas engines.

DESCRIPTION OF SYMBOLS 20 ... Fuel injection valve, 21 ... Housing, 21a ... Accommodating space, 21b ... Injection hole, 21c ... Introduction passage, 21d ... Back pressure chamber, 21e ... Control chamber, 21f ... Discharge hole, 21g ... Discharge passage, 22 ... Needle valve , 23 ... Spring, 24 ... Control valve, 25 ... Spring, 26 ... Piezo element actuator, 31a ... Branch passage, 31b ... Supply passage, 32 ... Fuel tank, 33 ... Fuel pump, 34 ... Common rail, 35 ... Return passage, 40 DESCRIPTION OF SYMBOLS Electronic control unit 41 ... Water temperature sensor 42 ... Rotational speed sensor 43 ... Intake amount sensor 44 ... Vehicle speed sensor 45 ... Accelerator pedal depression amount sensor 46 ... Pressure sensor

Claims (6)

In an abnormality determination device for determining abnormality of a plurality of fuel injection valves respectively provided for a plurality of cylinders of an internal combustion engine,
A pressure sensor provided on each of the fuel injection valves for detecting the pressure of the fuel supplied to the corresponding fuel injection valve;
A determination unit that determines abnormality of the fuel injection valve based on a fuel change mode detected by the pressure sensor, and a fuel pressure change mode in the fuel injection valve that injected the fuel, and the fuel was not injected An abnormality determination device for a fuel injection valve, comprising: a determination unit that determines that an open sticking has occurred in a fuel injection valve that has injected fuel based on a fuel pressure change mode in the fuel injection valve. A first confirmation unit for confirming that no increase in pressure due to the closing of the fuel injection valve is observed in the fuel pressure change mode detected by a pressure sensor provided in the fuel injection valve that injected the fuel;
Second confirmation for confirming that no increase in pressure due to the closing of the fuel injection valve that injected the fuel is observed in the fuel pressure change mode detected by the pressure sensor provided in the fuel injection valve that did not inject the fuel And further comprising
The determination unit determines the fuel based on the fact that both the first confirmation unit and the second confirmation unit have confirmed that there is no increase in pressure due to the closing of the fuel injection valve that injected the fuel. The abnormality determination device according to claim 1, wherein it is determined that open sticking has occurred in the injected fuel injection valve. The first confirmation unit estimates a fuel pressure detected by a pressure sensor provided in a fuel injection valve that has injected fuel from a valve opening period after a valve closing command is issued to the fuel injection valve. The fuel injection valve is closed in the fuel pressure change mode detected by the pressure sensor provided in the fuel injection valve that injected the fuel based on the fact that the fuel pressure is less than the first threshold value that is smaller than the minimum fuel pressure. The abnormality determination device according to claim 2, wherein it is confirmed that no pressure increase due to the pressure is observed. The second confirmation unit is configured such that after the fuel pressure detected by the pressure sensor provided in the fuel injection valve that has not injected the fuel is instructed to close the fuel injection valve that has injected the fuel, Fuel detected by a pressure sensor provided in a fuel injection valve that did not inject fuel based on being less than or equal to a second threshold value that is smaller than a minimum fuel pressure estimated from a valve opening period associated with injection The abnormality determination device according to claim 2 or 3, wherein it is confirmed that a pressure increase due to closing of the fuel injection valve that injects fuel is not observed in a pressure change mode. The second confirmation unit includes a pressure sensor provided in a fuel injection valve that injects fuel next to a fuel injection valve that injects fuel among pressure sensors provided in fuel injection valves that have not injected fuel. The detected fuel pressure change mode is monitored, and it is confirmed that the fuel pressure change mode detected by the pressure sensor does not show a pressure increase due to closing of the fuel injection valve that injected the fuel. The abnormality determination device according to any one of 1 to 4. In a method for determining an abnormality of a plurality of fuel injection valves respectively provided for a plurality of cylinders of an internal combustion engine,
Detecting a pressure of fuel supplied to the corresponding fuel injection valve by a pressure sensor provided in each of the fuel injection valves; and
Confirming that there is no pressure increase due to closing of the fuel injection valve in the fuel pressure change mode detected by the pressure sensor provided in the fuel injection valve that injected the fuel;
Confirming that there is no increase in pressure due to the closing of the fuel injection valve that injected the fuel in the fuel pressure change mode detected by the pressure sensor provided in the fuel injection valve that did not inject the fuel;
There is no increase in pressure due to the closing of the fuel injection valve that injected the fuel in both the fuel pressure change mode in the fuel injection valve that injected the fuel and the fuel pressure change mode in the fuel injection valve that did not inject the fuel. Determining that open sticking has occurred in the fuel injection valve that injected the fuel based on the fact that it has been confirmed.

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