JP5287637B2 - Anomaly detection device - Google Patents

Description

  The present invention relates to an abnormality detection device that detects an abnormality of a fuel injection valve that injects fuel into an internal combustion engine.

  The internal combustion engine includes a fuel injection valve that injects fuel. For example, if an abnormality such as a change in the injection amount per unit time occurs in the fuel injection valve, it becomes difficult to stably operate the internal combustion engine. Thus, an abnormality detection device that detects an abnormality of the fuel injection valve has been proposed.

  In the case of Patent Document 1, the fuel injection valves respectively provided in the plurality of cylinders of the internal combustion engine are sequentially controlled to stop operation. At this time, if a fuel injection valve is detected in which the operation state of the internal combustion engine does not change even when control for stopping the operation is performed, it is determined that the fuel injection valve is abnormal. In the case of Patent Document 2, the abnormality of the fuel injection valve is detected from the rotational speed of the internal combustion engine, that is, the rotational speed of the crankshaft. In this case, the abnormality of the fuel injection valve is detected based on the correction amount of the fuel injection amount between the cylinders calculated from the deviation of the rotational speed of the crankshaft. Further, in the case of Patent Document 3, the abnormality of the fuel injection valve is detected by trying to inject fuel from the fuel injection valve after the operation of the fuel pump immediately after the internal combustion engine stops. In this case, the abnormality of the fuel injection valve is detected based on a change in fuel pressure caused by injecting fuel from the fuel injection valve.

  However, in the case of Patent Document 1, the fuel injection is stopped not only for an abnormal fuel injection valve but also for a normal fuel injection valve. Therefore, in the case of Patent Document 1, there is a problem that a change in the operating state of the internal combustion engine and a deterioration in operability occur while detecting an abnormality. Further, in the case of Patent Document 2, if an abnormality occurs in a plurality of fuel injection valves, the normal fuel injection valve is subjected to excessive correction in order to reduce the rotational speed deviation. As a result, due to excessive correction, the fuel injection amount of the normal fuel injection valve may exceed the determination value and may be determined to be abnormal. Furthermore, in the case of Patent Document 3, since it is necessary to inject fuel after the operation of the internal combustion engine is stopped, dilution of the lubricating oil or the like may occur, which may cause a malfunction of the internal combustion engine.

JP 2009-150246 A JP-A-2-5736 JP 2004-308464 A

  Therefore, an object of the present invention is to provide a highly accurate abnormality detection device in which an abnormal increase / decrease in the fuel injection amount is detected without causing a change or malfunction of the operation state.

  According to the first aspect of the present invention, the abnormal fuel injection valve specifying means performs fuel injection based on the injection correction amount for each fuel injection valve acquired by the correction amount acquisition means and the total injection amount calculated by the total injection amount calculation means. It is specified which of the valves the fuel injection valve is abnormal. If an abnormality occurs in any one of the fuel injection valves, the fuel injection amount of the abnormal fuel injection valve becomes excessive or excessive as compared with other fuel injection valves. Therefore, the difference in the injection correction amount becomes large between the normal fuel injection valve and the abnormal fuel injection valve. On the other hand, the injection correction amount is a relative amount between the fuel injection valves. Therefore, it is not possible to distinguish between a normal fuel injection valve and an abnormal fuel injection valve only by the difference in the injection correction amount. Therefore, the abnormal fuel injection valve specifying means detects abnormality of the fuel injection valve in consideration of not only the injection correction amount but also the total injection amount. Therefore, an abnormal increase or decrease in the amount of fuel injected by the fuel injection valve can be detected, and an abnormality in the fuel injection valve can be accurately detected.

  In the first aspect of the invention, the injection correction amount and the total injection amount that are used by the abnormal fuel injection valve specifying means for determining the abnormality of the fuel injection valve are both obtained when the internal combustion engine is maintained in the idle state. Is done. The injection correction amount and the total injection amount are obtained without stopping the fuel injection from the fuel injection valve or changing the fuel injection amount, for example. Therefore, the abnormality of the fuel injection valve can be detected without causing a change or malfunction of the operating state of the internal combustion engine.

  In the invention according to claim 2, the abnormal fuel injection valve specifying means determines whether or not the injection correction amount is within an appropriate range for each fuel injection valve. For example, when the fuel injection amount is excessive in an abnormal fuel injection valve, the injection correction amount is set in a direction to reduce the injection amount in the fuel injection valve. This injection correction amount is expanded in the direction of reducing the injection amount as the injection amount at the abnormal fuel injection valve becomes excessive, and exceeds the appropriate range. Therefore, by determining whether or not the injection correction amount of each fuel injection valve is within an appropriate range, a fuel injection valve that may have an abnormality is identified. On the other hand, as described above, the injection correction amount is a relative amount between the fuel injection valves. Therefore, it is difficult to determine that the fuel injection valve is abnormal because the injection correction amount is simply not within the appropriate range. Therefore, when the abnormal fuel injection valve specifying unit determines that any of the injection correction amounts is not within the appropriate range in the plurality of fuel injection valves, it determines whether the average value of the total injection amounts is within the appropriate injection amount range. . This total injection amount is the sum of the injection amounts of fuel injected from the fuel injection valves by applying the injection correction amount in the idle state. The average value per cylinder is calculated by dividing the total injection amount by the number of cylinders of the internal combustion engine. It is determined whether or not the average value of the total injection amount is within the appropriate injection amount range. When the internal combustion engine is maintained in an idle state, all the fuel injection valves are corrected with an increase or decrease in the injection correction amount for the purpose of compensating for the abnormal fuel injection valves. For this reason, in a normal fuel injection valve, the corrected fuel injection amount is excessively large or small. As a result, by considering the average value of the total injection amount, it is determined whether or not the fuel injection valve whose injection correction amount is not in the appropriate range is abnormal. Therefore, it is possible to accurately detect an abnormal fuel injection valve including an excessive injection amount or an excessive injection amount.

  In the invention according to claim 3, the upper limit threshold and the lower limit threshold are set according to the ratio of the fuel injection valves that become abnormal. The injection correction amount varies depending on the proportion of fuel injection valves that become abnormal. Therefore, the appropriate range between the upper limit threshold and the lower limit threshold varies depending on the ratio of fuel injection valves that become abnormal. Therefore, by setting the upper limit threshold and the lower limit threshold according to the ratio of the fuel injection valves, an abnormal fuel injection valve can be detected with higher accuracy.

  In the invention according to claim 4, the upper limit threshold and the lower limit threshold are set according to the operating state of the internal combustion engine. Even when the internal combustion engine is in an idle state, the load on the internal combustion engine may change due to, for example, the operation of a power supply device or an air conditioning device. In this case, the amount of fuel injected from each fuel injection valve also changes. Therefore, by setting the upper limit threshold and the lower limit threshold according to the operating state, an abnormal fuel injection valve can be detected with higher accuracy regardless of the operating state of the internal combustion engine.

The schematic diagram which shows the structure of the diesel engine system to which the abnormality detection apparatus by one Embodiment of this invention is applied. Schematic which shows the flow of an operation | movement of the abnormality detection apparatus by one Embodiment. Explanatory drawing which shows the conditions of abnormality determination by the abnormality detection apparatus by one Embodiment, and the distribution image of injection correction amount

Hereinafter, a diesel engine system to which an abnormality detection apparatus according to an embodiment of the present invention is applied will be described with reference to the drawings.
A diesel engine system 10 shown in FIG. 1 includes a diesel engine (hereinafter referred to as “engine”) 11 as an internal combustion engine and an abnormality detection device 12. The engine 11 includes an engine body 13 and a fuel injection unit 14. The engine body 13 has a plurality of cylinders 15. An engine 11 shown in FIG. 1 is a four-cylinder engine having four cylinders 15. The engine 11 is not limited to a diesel engine as in the present embodiment, but may be a gasoline engine. The fuel injection unit 14 has an injector 16 as a fuel injection valve. The injector 16 is provided in each cylinder 15 of the engine body 13. The fuel injection unit 14 includes a fuel pump 17, a common rail 18, and an injection control unit 19 in addition to the injector 16. The fuel pump 17 pressurizes the fuel stored in the fuel tank 21 and supplies it to the common rail 18. The common rail 18 stores the fuel pressurized by the fuel pump 17 in a pressure accumulation state. The injector 16 injects fuel stored in the common rail 18 into each cylinder 15 of the engine body 13. In the case of this embodiment, the injector 16 is a direct injection type injector, and injects fuel into the air sucked into the cylinder 15 of the engine body 13.

  The abnormality detection device 12 includes a control unit 31, an injection control unit 19, an idle operation control unit 32, a correction amount calculation unit 33, an injection correction amount acquisition unit 34, a total injection amount calculation unit 35, an abnormal injector specification unit 36, and a storage unit 37. The operation state detection unit 38 and the injection amount setting unit 39 are provided. The control unit 31 includes a microcomputer having a CPU, a ROM, and a RAM. The CPU of the control unit 31 controls the entire diesel engine system 10 including the engine 11 and the abnormality detection device 12 according to a computer program stored in the ROM. The injection control unit 19, the idle operation control unit 32, the correction amount calculation unit 33, the injection correction amount acquisition unit 34, the total injection amount calculation unit 35, the abnormal injector specification unit 36, and the injection amount setting unit 39 are computer programs in the control unit 31. This is realized by software. The injection control unit 19, the idle operation control unit 32, the correction amount calculation unit 33, the injection correction amount acquisition unit 34, the total injection amount calculation unit 35, the abnormal injector specification unit 36, and the injection amount setting unit 39 are configured by hardware. It may be realized.

The injection control unit 19 controls the injection of fuel from the injector 16 by outputting a drive signal to a drive unit (not shown) of the injector 16. This drive signal opens and closes a nozzle hole (not shown) of the injector 16 and intermittently injects fuel from the nozzle hole. For example, when the fuel injection amount from the injector 16 is increased, the injection control unit 19 sets the drive signal so that the time during which the injection hole of the injector 16 is opened is lengthened. The injection control unit 19 controls the fuel injection from each injector 16 based on the fuel injection amount set according to the operation state of the engine 11 detected by the operation state detection unit 38.
The idle operation control unit 32 operates the engine 11 in an idle state. That is, the idle operation control unit 32 maintains the engine 11 at a low speed to such an extent that the engine 11 can continue the autonomous operation. At this time, the injection control unit 19 sets the fuel injection amount from the injector 16 so that the engine 11 can maintain the idle state.

The correction amount calculation unit 33 calculates an injection correction amount TQk for correcting the fuel injection amount between the injectors 16 provided in each cylinder 15 of the engine body 13. Here, the subscript k is the number of the cylinder 15. As shown in FIG. 1, in the case of the four-cylinder engine 11, the subscript k is any one of “1” to “4”. The injector 16 has a difference in injection characteristics for each individual, such as a fuel injection amount per unit time. Further, the injection characteristics change every moment even for the same individual due to the biting or accumulation of foreign matter accompanying the use of the injector 16 over time. Therefore, in order to maintain the engine 11 in a stable operating state, it is necessary to equalize the fuel injection amount from the injectors 16 provided in each cylinder 15 of the engine body 13. Therefore, the correction amount calculation unit 33 corrects the fuel injection amount from each injector 16 in order to equalize the fuel injection amount from each injector 16 in consideration of the injection characteristics that are different for each injector 16. . The injection correction amount acquisition unit 34 acquires the injection correction amount TQk corrected for each injector 16 by the correction amount calculation unit 33 from the correction amount calculation unit 33. More specifically, the injection correction amount acquisition unit 34 determines the injection correction amount for each injector 16 from the correction amount calculation unit 33 when the engine 11 is maintained in the idle state and the fuel injection amount from the injector 16 is corrected. Get TQk.
The total injection amount calculation unit 35 calculates the total amount of fuel injected from the plurality of injectors 16 as the total injection amount Q when the engine 11 is maintained in the idle state. In this case, the total injection amount calculation unit 35 calculates the total amount of fuel injected from each injector 16 as the total injection amount Q in consideration of the injection correction amount TQk calculated by the correction amount calculation unit 33.

  The abnormal injector specifying unit 36 selects any one of the plurality of injectors 16 based on the injection correction amount TQk for each injector 16 acquired by the injection correction amount acquisition unit 34 and the total injection amount Q calculated by the total injection amount calculation unit 35. It is specified whether an abnormality has occurred in the injector 16. The abnormal injector specifying unit 36 includes an injection correction amount range determining unit 41 and an average injection amount range determining unit 42. The injection correction amount range determination unit 41 determines whether or not the injection correction amount TQk is within an appropriate range for each injector 16 acquired by the injection correction amount acquisition unit 34. The injection correction amount TQk is set in consideration of the injection characteristics for each injector 16 as described above. Therefore, there are cases where the injection characteristics cannot be improved by correcting the injection amount depending on the degree of abnormality of the injector 16. As described above, when the injection characteristic cannot be improved by correcting the injection amount, the injection correction amount TQk exceeds the predetermined appropriate range between the upper limit threshold (+ THF) and the lower limit threshold (−THFa). Become. In this way, the injection correction amount range determination unit 41 determines whether or not the injection correction amount TQk of each injector 16 is within the appropriate range, that is, whether or not it is between the upper limit threshold (+ THFa) and the lower limit threshold (−THFa). to decide. The upper limit threshold (+ THFa) and the lower limit threshold (−THFa) are set according to the ratio of the number of injectors 16 that are determined to be abnormal with respect to the total number of injectors 16, and are stored in the storage unit 37.

  On the other hand, the average injection amount range determination unit 42 determines whether or not the average injection amount QFIN obtained by dividing the total injection amount Q calculated by the total injection amount calculation unit 35 by the number of cylinders n is within the appropriate injection amount range. The total injection amount Q is also determined in consideration of the injection characteristics for each injector 16 as described above. Therefore, a large error occurs in the average injection amount QFIN depending on the degree of abnormality of the injector 16. When an error occurs in the average injection amount QFIN in this way, the average injection amount QFIN exceeds the appropriate injection amount range defined between the preset upper limit average injection amount THQH and the lower limit average injection amount THQL. . Thus, the average injection amount range determination unit 42 determines whether the average injection amount QFIN is within the appropriate injection amount range, that is, whether it is between the upper limit average injection amount THQH and the lower limit average injection amount THQL. The upper limit average injection amount THQH and the lower limit average injection amount THQL correspond to the fuel injection amount that becomes the upper limit or the fuel injection amount that becomes the lower limit when the engine 11 is maintained in the idle state in the idle operation control unit 32, respectively. Yes. That is, the upper limit of the fuel injection amount when the engine 11 is maintained in the idle state is the upper limit average injection amount THQH, and the lower limit of the fuel injection amount is the lower limit average injection amount THQL. A range between the upper limit average injection amount THQH and the lower limit average injection amount THQL corresponds to an appropriate injection amount range.

  The storage unit 37 includes, for example, a nonvolatile memory. The storage unit 37 stores, as an abnormal fuel injection valve, the injector 16 that is specified as having an abnormality in the abnormal injector specifying unit 36. The storage unit 37 is not limited to the nonvolatile memory as described above, and any recording medium can be applied. The storage unit 37 may be shared with the ROM and RAM of the control unit 31. The storage unit 37 may store not only the abnormal fuel injection valve but also, for example, various types of data that need to be stored by the computer program or the abnormality detection device 12. The memory | storage part 37 comprises the abnormal fuel injection valve memory | storage means of a claim with the control part 31. FIG.

  The operation state detection unit 38 includes an accelerator sensor 43, a rotation speed sensor 44, a water temperature sensor 45, and the like. The accelerator sensor 43 detects the amount of depression of an accelerator pedal (not shown). The rotation speed sensor 44 detects the rotation speed of the crankshaft of the engine 11. The water temperature sensor 45 detects the temperature of the cooling water of the engine 11. The driving state detection unit 38 determines whether the accelerator pedal 43 is detected by the accelerator sensor 43, the rotation speed of the crankshaft detected by the rotation speed sensor 44, the temperature of the cooling water detected by the water temperature sensor 45, and the like. 11 operation states, that is, load states are detected.

  The upper limit threshold (+ THFa) and the lower limit threshold (−THFa) used by the injection correction amount range determination unit 41 are set according to the operation state of the engine 11 detected by the operation state detection unit 38. The operating state detection unit 38 is not limited to the accelerator sensor 43, the rotation speed sensor 44, and the water temperature sensor 45, such as an outside air temperature sensor that detects the outside air temperature or a voltage sensor that detects a power generation voltage of a generator driven by the engine 11. A configuration for detecting other operating states may be included.

  The injection amount setting unit 39 sets the fuel injection amount based on the operation state of the engine 11 detected by the operation state detection unit 38. Then, the injection amount setting unit 39 adds the correction amount for each injector 16 calculated by the correction amount calculation unit 33 to the fuel injection amount set based on the operating state of the engine 11 to determine the final fuel injection amount. Set. The injection control unit 19 outputs a drive signal to each injector 16 based on the fuel injection amount set by the injection amount setting unit 39.

Next, the operation of the abnormality detection device 12 configured as described above will be described with reference to FIG.
When the operation of the engine 11 is started, the control unit 31 determines whether or not the engine 11 is in an idle state (S101). Specifically, the control unit 31 determines whether or not ISC (Idol Speed Control) control is being performed on the engine 11 by the idle operation control unit 32. When the control unit 31 determines that the engine 11 is not in the idle state (S101: No), the control unit 31 returns to S101.

  If the control unit 31 determines that the engine 11 is in an idle state, that is, determines that ISC control is being executed (S101: Yes), whether or not the load condition of the engine 11 is within a preset detectable range. Is determined (S102). Even when the engine 11 is in an idle state, for example, a load applied to the engine 11 from peripheral devices such as electrical components and air conditioners driven by the engine 11 may increase. Thus, when the load applied to the engine 11 is large, the operating state of the engine 11 is changed due to the fluctuation of the load, and there is a possibility that the accuracy of abnormality detection is reduced. Therefore, the control unit 31 determines whether or not the load condition of the engine 11 is within a detectable range. This detectable range can be arbitrarily set as long as the accuracy of abnormality detection can be maintained.

  When the control unit 31 determines that the load condition is not within the detectable condition range (S102: No), the control unit 31 returns to S101. On the other hand, when the control unit 31 determines that the load condition is within the detectable range (S102: Yes), the inter-cylinder injection amount correction control (hereinafter, the inter-cylinder injection amount correction control is abbreviated as “FCCB control”). It is determined whether it is executed (S103). When the ISC control is being executed by the idle operation control unit 32, the control unit 31 is executing the FCCB control in order to stabilize the operation state of the engine 11. That is, the control unit 31 calculates the injection correction amount TQk injected from the injector 16 of each cylinder 15 in the correction amount calculation unit 33, and corrects the fuel injection amount based on the injection correction amount TQk. Variations in fuel injection amount from are reduced. As described above, the control unit 31 determines whether or not the FCCB control is executed simultaneously with the ISC control.

  When determining that the FCCB control is not being executed (S103: No), the control unit 31 returns to S101. On the other hand, if it is determined that the FCCB control is being executed (S103: Yes), the injection correction amount acquisition unit 34 acquires the correction value by the FCCB control as the injection correction amount TQk for each injector 16 (S104). The injection correction amount acquisition unit 34 acquires, for each injector 16, the injection correction amount TQk calculated by the correction amount calculation unit 33 in S103.

  When the injection correction amount TQk is acquired, the total injection amount calculation unit 35 calculates the total injection amount Q and the average injection amount QFIN (S105). The total injection amount calculation unit 35 calculates the total injection amount Q by integrating the individual fuel injection amounts QFINk injected from the injectors 16 provided in the cylinders 15 of the engine body 13, and calculates the calculated total injection amount Q Is divided by the number of cylinders n of the engine body 13. Thus, the average injection amount QFIN is calculated as QFIN = Q / n. For example, as shown in FIG. 1, in the case of a four-cylinder engine 11, the average injection amount is obtained by dividing the total injection amount Q, which is the sum of the fuel injection amounts injected from the four injectors 16, by 4, which is the number of cylinders. QFIN is calculated. In this case, the individual fuel injection amount QFINk in each injector 16 used for calculating the total injection amount Q is the corrected injection amount after the injection amount correction is performed between the injectors 16 when the ISC control is executed, that is, It is calculated including the injection correction amount TQk.

  The control unit 31 determines whether or not the injection correction amount TQk for each injector 16 calculated in S104 is stable (S106). Even if the engine 11 shifts to the idle state and the ISC control and the FCCB control are executed, the injection correction amount TQk may fluctuate when there is a transient condition such as immediately after the transition to the idle state. Therefore, the control unit 31 monitors the acquired injection correction amount TQk until the injection correction amount TQk is stabilized. The period until the injection correction amount TQk is stabilized is, for example, about a fraction of a second to several seconds.

  When determining that the injection correction amount TQk is not stable (S106: No), the control unit 31 returns to S101. On the other hand, when determining that the injection correction amount TQk is stable, the abnormal injector specifying unit 36 determines whether or not the injection correction amount TQk is outside the appropriate range for each injector 16 in the injection correction amount range determining unit 41. (S107). The fuel injection amount from the injector 16 may be excessive or small. Therefore, the injection correction amount TQk is a positive or negative value with the correction amount “0” serving as the reference value as the center, as shown in FIG. The injection correction amount range determination unit 41 determines whether the injection correction amount TQk that is a positive or negative value is within an appropriate range between the upper limit threshold (+ THF) and the lower limit threshold (−THFa) or outside the appropriate range. Judging. Here, the suffix “a” of the upper limit threshold (+ THFa) and the lower limit threshold (−THFa) indicates the number of injectors 16 that may be determined to be abnormal. In the flow shown in FIG. 2, the number of injectors 16 that may be determined to be abnormal in S107 is unknown. Therefore, as shown in FIG. 3, first, an upper limit threshold (+ THF1) and a lower limit threshold (−THF1) are selected on the assumption that one of the four injectors 16 is abnormal. The upper threshold (+ THF1) and the lower threshold (−THF1) are stored in the storage unit 37, the ROM of the control unit 31, or the like. Further, the upper limit threshold (+ THFa) and the lower limit threshold (−THFa) are set according to the ratio of the number of injectors 16 that may be determined to be abnormal with respect to the total number of injectors 16.

  If the injection correction amount range determining unit 41 determines that the injection correction amounts TQk of all the injectors 16 are not outside the appropriate range, that is, within the appropriate range (S107: No), the control unit 31 repeats the processing from S101. On the other hand, when the injection correction amount range determining unit 41 determines that the injection correction amount TQk of any of the injectors 16 is outside the appropriate range (S107: Yes), the abnormal injector specifying unit 36 determines that the injection correction amount TQk is outside the appropriate range. It is determined whether there are two or more injectors 16 (S108). The injection correction amount range determination unit 41 determines whether or not the set injection correction amount TQk is outside the appropriate range for each injector 16 provided in each cylinder 15 in S107. At this time, the abnormal injector specifying unit 36 determines whether or not there are two or more injectors 16 whose injection correction amounts TQk are outside the appropriate range in order to specify which of the injectors 16 is abnormal. .

  If the abnormal injector specifying unit 36 determines that there are not two or more injectors 16 whose injection correction amount TQk is outside the proper range, that is, only one injector 16 is outside the proper range (S108: No), it is out of the proper range. It is determined whether or not the injection correction amount TQk of the injector 16 that has become equal to or greater than the upper threshold (+ THFa) (S109). At this time, since there is only one injector 16 outside the appropriate range, the upper threshold (+ THF1) is applied as shown in FIG.

  When the abnormal injector specifying unit 36 determines that the injection correction amount TQk of the injector 16 that is out of the appropriate range is equal to or greater than the upper threshold (+ THFa = + THF1) (S109: Yes), the average injection amount range determining unit 42 performs the average injection. It is determined whether the amount QFIN is equal to or less than the lower limit average injection amount THQL (S110). If the abnormal injector specifying unit 36 determines that the average injection amount QFIN is not less than or equal to the lower limit average injection amount THQL, that is, the average injection amount QFIN is greater than the lower limit average injection amount THQL (S110: No), the injection correction amount TQk is appropriate in S107. It is specified that the injector 16 that is out of range is abnormal (S111). On the other hand, if the abnormal injector specifying unit 36 determines that the average injection amount QFIN is equal to or less than the lower limit average injection amount THQL (S110: Yes), the remaining injectors except the injector 16 whose injection correction amount TQk is outside the appropriate range in S107. It is specified that the injector 16 is abnormal (S112).

  In S108 and S109, when it is determined that only the injection correction amount TQk of one injector 16 is equal to or higher than the upper limit threshold (+ THF1), only the injector 16 that is equal to or higher than the upper limit threshold (+ THF1) is abnormal or the upper limit threshold ( Only the injector 16 that is + THF 1) or higher is considered normal. In the case of the four-cylinder engine 11 as in the present embodiment, four injectors 16 are provided. If one of the four injectors 16 is normal, the other three injectors 16 become abnormal. Thus, when the three injectors 16 are abnormal, the injection amount correction is performed so that the fuel injection amounts from the abnormal three injectors 16 and the normal one injector 16 are made uniform. As a result, the injection correction amount TQk of the normal injector 16 becomes equal to or greater than the upper limit threshold value (+ THF1) due to the influence of the abnormal three injectors 16. That is, only by determining whether or not the injection correction amount TQk is within the appropriate range, it is determined whether only the injector 16 having the injection correction amount TQk equal to or greater than the upper limit threshold (+ THF1) is abnormal or normal. It is difficult.

  Here, when the average injection amount QFIN is larger than the lower limit average injection amount THQL, the average injection amount QFIN is included in the appropriate injection amount range. The average injection amount QFIN becomes out of the appropriate injection amount range as the number of injectors 16 that become abnormal increases. In particular, when the three injectors 16 are abnormal, the ratio of the abnormal injectors 16 to the total number of the injectors 16 increases, so the average injection amount QFIN is outside the appropriate injection amount range.

  If it is determined in S110 that the average injection amount QFIN is equal to or greater than the lower limit average injection amount THQL based on the above conditions, it is determined in S107 that only one injector 16 for which the injection correction amount TQk is determined to be outside the proper range is abnormal. Is done. At the same time, the injection correction amount TQk of the injector 16 determined to be abnormal is set excessively in order to increase the fuel injection amount. Therefore, the injector 16 determined to be abnormal is determined to be abnormal in which the fuel injection amount becomes excessively small. Also, when the average injection amount QFIN is within the appropriate injection amount range, that is, THQL <QFIN <THQH, it is determined that only one injector 16 for which the injection correction amount TQk is determined to be outside the appropriate range in S107 is abnormal. The

  On the other hand, if it is determined in S110 that the average injection amount QFIN is equal to or less than the lower limit average injection amount THQL, the remaining three injectors 16 except for the one injector 16 in which the injection correction amount TQk is determined to be outside the proper range in S107. Is determined to be abnormal. At the same time, one injector 16 for which the injection correction amount TQk is determined to be out of the proper range is set with an excessive injection correction amount TQk in order to match the excessive fuel injection amount of the abnormal three injectors 16. Will be. Therefore, the three injectors 16 that are determined to be abnormal are determined to be abnormal in which the fuel injection amount becomes excessive.

  If the abnormal injector specifying unit 36 determines that the injection correction amount TQk of the injector 16 that is out of the appropriate range in S109 is not equal to or greater than the upper threshold (+ THF1) (S109: No), the average injection amount range determining unit 42 determines the average injection amount. It is determined whether or not QFIN is greater than or equal to the upper limit average injection amount THQH (S113). The abnormal injector specifying unit 36 determines whether or not the injection correction amount TQk is outside the appropriate range for each injector 16 in S107, and when the injection correction amount TQk is not within the appropriate range, the processing after S108 is continued. Therefore, when the injection correction amount TQk of the injector 16 that is out of the appropriate range in S109 is not equal to or higher than the upper limit threshold (+ THF1), it is determined that the injection correction amount TQk of the injector 16 is equal to or lower than the lower limit threshold (−THF = −THF1). become.

  As described above, when the abnormal injector specifying unit 36 determines in S109 that the injection correction amount TQk of the injector 16 is equal to or lower than the lower limit threshold (−THF1), it is determined in S113 whether or not the average injection amount QFIN is equal to or higher than the upper limit average injection amount THQH. to decide. If the abnormal injector specifying unit 36 determines that the average injection amount QFIN is not equal to or greater than the upper limit average injection amount THQH, that is, the average injection amount QFIN is less than the upper limit average injection amount (S113: No), the injection correction amount TQk is appropriate in S107. It is specified that the injector 16 that is out of range is abnormal (S114). On the other hand, when the abnormal injector specifying unit 36 determines that the average injection amount QFIN is greater than or equal to the upper limit average injection amount THQH (S113: Yes), the remaining injectors except the injector 16 whose injection correction amount TQk is outside the proper range in S107. It is specified that the injector 16 is abnormal (S115).

  In S108 and S109, when it is determined that only the injection correction amount TQk of one injector 16 is equal to or lower than the lower threshold (-THF1), only the injector 16 that is equal to or lower than the lower threshold (-THF1) is abnormal or lower Only the injector 16 that is equal to or less than the threshold value (−THF1) is considered normal. In the case of the four-cylinder engine 11 as in the present embodiment, four injectors 16 are provided. If one of the four injectors 16 is normal, the other three injectors 16 become abnormal. When there is an abnormality in the three injectors 16 in this way, the injection amount correction is performed so that the fuel injection amounts from the abnormal three injectors 16 and the normal one injector 16 are made uniform. As a result, the injection correction amount TQk of the normal injector 16 becomes equal to or lower than the lower limit threshold (−THF 1) due to the influence of the abnormal three injectors 16. That is, only by determining whether or not the injection correction amount TQk is within the appropriate range, it is determined whether only the injector 16 having the injection correction amount TQk equal to or lower than the lower limit threshold (−THF1) is abnormal or normal. It is difficult.

  Here, when the average injection amount QFIN is less than the upper limit average injection amount THQH, the average injection amount QFIN is included in the appropriate injection amount range. The average injection amount QFIN becomes out of the appropriate injection amount range as the number of injectors 16 that become abnormal increases. In particular, when the three injectors 16 are abnormal, the ratio of the abnormal injectors 16 to the total number of the injectors 16 increases, so the average injection amount QFIN is outside the appropriate injection amount range.

  When the average injection amount QFIN is determined to be less than the upper limit average injection amount THQH in S113 due to the above conditions, it is determined that only one injector 16 for which the injection correction amount TQk is determined to be outside the appropriate range in S107 is abnormal. Is done. At the same time, the injection correction amount TQk of the injector 16 determined to be abnormal is set to be too small in order to reduce the fuel injection amount. Therefore, the injector 16 determined to be abnormal is determined to be abnormal in which the fuel injection amount becomes excessive. Also, when the average injection amount QFIN is within the appropriate injection amount range, that is, THQL <QFIN <THQH, it is determined that only one injector 16 for which the injection correction amount TQk is determined to be outside the appropriate range in S107 is abnormal. The

  On the other hand, if it is determined in S113 that the average injection amount QFIN is equal to or greater than the upper limit average injection amount THQH, the remaining three injectors 16 except for the one injector 16 in which the injection correction amount TQk is determined to be outside the proper range in S107. Is determined to be abnormal. At the same time, one injector 16 for which the injection correction amount TQk is determined to be out of the proper range is set with an excessive injection correction amount TQk to match the excessive fuel injection amount of the abnormal three injectors 16. Will be. Therefore, the three injectors 16 determined to be abnormal are determined to be abnormal in which the fuel injection amount becomes excessively small.

  If the abnormal injector specifying unit 36 determines that there are two or more injectors 16 that are outside the appropriate range of the injection correction amount TQk in S108 (S108: Yes), the average injection amount range determining unit 42 determines the average injection amount QFIN and the appropriate injection amount. The range is compared (S120). Specifically, the average injection amount range determination unit 42 determines whether “A: QFIN ≦ THQL”, “B: THQL <QFIN <THQH”, or “C: THQH ≦ QFIN?” "Is determined. That is, the average injection amount range determination unit 42 determines whether the average injection amount QFIN is “A: is lower than or equal to the lower limit average injection amount THQL”, “B: is included in the appropriate injection amount range”, or “C: upper limit average injection. It is determined whether or not the amount is THQH or more.

  If it is determined that “A: QFIN ≦ THQL” in S120 (S120: A), the abnormal injector specifying unit 36 determines all of the injectors 16 in which the injection correction amount TQk calculated in S104 is equal to or less than the lower threshold (−THFa). It is determined that the fuel injection amount is abnormal (S121). Further, when it is determined that “B: THQL <QFIN <THQH” in S120 (S120: B), the abnormal injector specifying unit 36 causes all the injectors 16 provided in the engine 11 to have excessive or small fuel injection amounts. Regardless, it is determined to be abnormal (S122). Furthermore, if it is determined that “C: THQH ≦ QFIN” in S120 (S120: C), the abnormal injector specifying unit 36 determines all of the injectors 16 in which the injection correction amount TQk calculated in S104 is equal to or greater than the upper threshold (+ THFa). Is judged as an abnormality in which the fuel injection amount becomes excessively small (S123). In this case, since there are two or more injectors 16 that are out of the proper range in S121 and S123, the upper threshold (+ THF2) and the lower threshold (-THF2) are applied as shown in FIG.

  The injector 16 whose injection correction amount TQk is outside the proper range is determined to be “A: QFIN ≦ THQL” in S120, that is, when it is determined that the average injection amount QFIN is equal to or lower than the lower limit average injection amount THQL, the fuel injection amount is reduced. It is controlled. Therefore, the injector 16 whose injection correction amount TQk is outside the appropriate range has an excessive fuel injection amount, and the injection correction amount TQk is set to a value on the negative side of the reference value “0”, thereby reducing the fuel injection amount. ing. Therefore, when it is determined in S108 that there are two or more injectors 16 whose injection correction amount TQk is outside the proper range, the injector 16 in which the average injection amount QFIN is determined to be equal to or lower than the lower limit average injection amount THQL in S120. In any case, it is determined that the fuel injection amount is abnormal.

  Similarly, the injector 16 whose injection correction amount TQk is outside the appropriate range is determined as “C: THQH ≦ QFIN” in S120, that is, when it is determined that the average injection amount QFIN is equal to or greater than the upper limit average injection amount THQH. It is controlled to increase. Therefore, the injector 16 whose injection correction amount TQk is outside the appropriate range has an excessively small fuel injection amount, and the injection correction amount TQk is set to a value on the positive side of the reference value “0”, thereby increasing the fuel injection amount. ing. Therefore, when it is determined in S108 that there are two or more injectors 16 whose injection correction amount TQk is outside the appropriate range, the injector 16 in which the average injection amount QFIN is determined to be equal to or greater than the upper limit average injection amount THQH in S120. In any case, it is determined that the fuel injection amount is abnormal.

Further, the injector 16 whose injection correction amount TQk is outside the appropriate range is determined as “B: THQL <QFIN <THQH” in S120, that is, the average injection amount QFIN is between the lower limit average injection amount THQL and the upper limit average injection amount THQH. As a result of setting the injection correction amount TQk in which the fuel injection amount set for each injector 16 exceeds the upper limit threshold (+ THF2) or the lower limit threshold (−THF2) when determined to be in the appropriate injection amount range, as a whole It is within the proper injection amount range. Therefore, when it is determined in S108 that there are two or more injectors 16 whose injection correction amount TQk is outside the appropriate range, the injector 16 in which the average injection amount QFIN is determined to be in the appropriate injection amount range in S120. Regardless of whether the fuel injection amount is excessive or small, it is determined that all are abnormal.
When the abnormal injector specifying unit 36 specifies the injector 16 that becomes abnormal in S111, S112, S114, S115, S121, S122, and S123, it stores the specified injector 16 in the storage unit 37 (S124). Then, when the storage of the specified injector 16 is completed, the control unit 31 returns to S101.

  In the embodiment described above, the abnormal injector specifying unit 36 calculates the injection correction amount TQk for each injector 16 acquired by the injection correction amount acquisition unit 34 and the total injection amount Q calculated by the total injection amount calculation unit 35. Based on the average injection amount QFIN, it is specified which of the plurality of injectors 16 has an abnormality. When an abnormality occurs in any of the injectors 16, the fuel injection amount of the abnormal injector 16 is excessive or small as compared with the other injectors 16. Therefore, the difference between the injection correction amount TQk of the normal injector 16 and the injection correction amount TQk of the abnormal injector 16 becomes large. On the other hand, the injection correction amount TQk is a relative amount between the injectors 16. Therefore, the normal injector 16 and the abnormal injector 16 cannot be distinguished only by the difference in the injection correction amount TQk. Therefore, the abnormal injector specifying unit 36 detects an abnormality of the injector 16 in consideration of not only the injection correction amount TQk but also the average injection amount QFIN calculated from the total injection amount Q. Therefore, an abnormal increase or decrease in the fuel injection amount by the injector 16 can be detected, and the abnormality of the injector 16 can be detected with high accuracy.

  In one embodiment, both the injection correction amount TQk and the total injection amount Q that are used by the abnormal injector specifying unit 36 for determining the abnormality of the injector 16 are acquired when the engine 11 is maintained in the idle state. The injection correction amount TQk and the total injection amount Q are obtained without stopping the fuel injection from the injector 16 or changing the fuel injection amount, for example. Therefore, the abnormality of the injector 16 can be detected without causing a change or malfunction of the operating state of the engine 11.

  In one embodiment, the abnormal injector specifying unit 36 determines whether or not the injection correction amount TQk is within an appropriate range for each injector 16. For example, when the fuel injection amount is excessive in an abnormal injector 16, the injection correction amount TQk is set in a direction to reduce the fuel injection amount in the injector 16. The injection correction amount TQk is expanded in the direction of decreasing the fuel injection amount as the fuel injection amount in the abnormal injector 16 becomes excessive, and exceeds the appropriate range. Therefore, by determining whether or not the injection correction amount TQk of each injector 16 is within an appropriate range, the injector 16 that may have an abnormality is identified. On the other hand, as described above, the injection correction amount TQk is a relative amount between the injectors 16. Therefore, it is difficult to determine that the injector 16 is abnormal because the injection correction amount TQk is not in the appropriate range. Therefore, when the abnormal injector specifying unit 36 determines that any of the injection correction amounts TQk is not within the appropriate range in the plurality of injectors 16, the average injection amount QFIN, which is the average value of the total injection amounts Q, is within the appropriate injection amount range. Determine whether or not. When the engine 11 is maintained in the idle state, the fuel injection amount is corrected based on the increase or decrease of the injection correction amount TQk for all the injectors 16 in order to compensate for the fuel injection amount from the abnormal injector 16. Therefore, in the normal injector 16, the fuel injection amount after correction may be excessively large or small. As a result, by considering this average injection amount QFIN, it is determined whether or not the injector 16 whose injection correction amount TQk is not in the proper range is abnormal. Therefore, it is possible to accurately detect the abnormal injector 16 including whether the fuel injection amount is on the excessive side or the excessive side.

  Furthermore, in one embodiment, the upper limit threshold (+ THFa) and the lower limit threshold (−THFa) that define the appropriate range are set according to the proportion of the injectors 16 that are abnormal. The injection correction amount TQk varies depending on the ratio of the injector 16 that becomes abnormal. Therefore, the appropriate range between the upper limit threshold (+ THFa) and the lower limit threshold (-THFa) varies depending on the ratio of the injectors 16 that become abnormal. Therefore, by setting the upper threshold (+ THFa) and the lower threshold (−THFa) according to the ratio of the injectors 16 that are abnormal, the abnormal injectors 16 can be detected with higher accuracy.

(Other embodiments)
The present invention described above is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist thereof.
In the case of the above-described embodiment, in S102, the example in which it is determined whether or not the load condition of the engine 11 is within the detectable range has been described in order to reduce the influence on the detection accuracy due to the load variation of the engine 11. However, when the fluctuation of the load applied to the engine 11 is small or a constant load is applied, a plurality of upper limit threshold values (+ THFa) and lower limit threshold values (−THFa) used in S107 and the like are prepared according to the magnitude of the load. It is good also as a structure which selects a suitable upper and lower threshold value (+ THFa) and a lower limit threshold value (-THFa) according to.

  Thereby, the upper threshold (+ THFa) and the lower threshold (−THFa) are set according to the operating state of the engine 11. Even if the engine 11 is in an idle state, the load changes due to the operation of the power supply device or the air conditioning device. In this case, the fuel injection amount from each injector 16 also changes. Therefore, by setting the upper limit threshold (+ THFa) and the lower limit threshold (−THFa) according to the operating state of the engine 11, the abnormal injector 16 can be detected more accurately regardless of the operating state of the engine 11. .

  In the drawings, 11 is an engine (internal combustion engine), 12 is an abnormality detection device, 15 is a cylinder, 16 is an injector (fuel injection valve), 31 is a control unit (abnormal fuel injection valve storage means), and 32 is an idle operation control unit ( Idle operation means), 34 is an injection correction amount acquisition unit (injection correction amount acquisition means), 35 is a total injection amount calculation unit (total injection amount calculation means), 36 is an abnormal injector specifying unit (abnormal fuel injection valve specifying unit), Reference numeral 37 denotes a storage unit (abnormal fuel injection valve storage unit), 38 denotes an operation state detection unit (operation state detection unit), 41 denotes an injection correction amount range determination unit, and 42 denotes an average injection amount range determination unit.

Claims (4)

An abnormality detection device for detecting an abnormality of a fuel injection valve provided in each of a plurality of cylinders of an internal combustion engine,
Idle operation means for operating the internal combustion engine in an idle state;
When the internal combustion engine is maintained in the idle state by the idle operation means and the injection amount correction is performed to correct the amount of fuel injected from the fuel injection valve among the plurality of cylinders, each fuel Injection correction amount acquisition means for acquiring, as an injection correction amount, an injection amount corrected for each injection valve;
When the internal combustion engine is maintained in an idle state, the total amount of fuel injected from the plurality of fuel injection valves is calculated as the total injection amount by applying the injection correction amount acquired by the injection correction amount acquisition means. A total injection amount calculating means;
Based on the injection correction amount of each fuel injection valve acquired by the correction amount acquisition unit and the total injection amount calculated by the total injection amount calculation unit, any one of the plurality of fuel injection valves is selected. An abnormal fuel injection valve specifying means for specifying whether an abnormality has occurred;
Abnormal fuel injection valve storage means for storing the fuel injection valve specified as abnormal by the abnormal fuel injection valve specifying means as an abnormal fuel injection valve;
An abnormality detection device comprising: The abnormal fuel injection valve specifying means includes
The injection correction amount for each of the fuel injection valves acquired by the injection correction amount acquisition means is compared with the upper limit threshold value and the lower limit threshold value of the injection correction amount set in advance, and the injection is performed for each fuel injection valve. An injection correction amount range determining means for determining whether or not a correction amount is within an appropriate range between the upper limit threshold and the lower limit threshold;
When the injection correction amount range determining means determines that the injection correction amount is not in the appropriate range for any of the fuel injection valves, the fuel injection valve is determined to be out of the appropriate range according to the number of the fuel injection valves. The average injection amount obtained by dividing the injection correction amount, the upper and lower thresholds of the injection correction amount, and the total injection amount calculated by the total injection amount calculating means by the number of cylinders of the internal combustion engine And a comparison means for comparing the upper limit average injection amount and the lower limit average injection amount of the average injection amount set in advance in combination according to the case ,
A specifying means for specifying the abnormal fuel injection valve according to a comparison result of the comparing means;
The abnormality detection device according to claim 1, comprising:
  The upper limit threshold and the lower limit threshold are set according to a ratio of the number of the abnormal fuel injection valves specified by the abnormal fuel injection valve specifying means to the total number of the fuel injection valves. Item 3. The abnormality detection apparatus according to Item 2. An operation state detecting means for detecting an operation state of the internal combustion engine;
The abnormality detection device according to claim 2 or 3, wherein the upper limit threshold and the lower limit threshold are set according to an operation state of the internal combustion engine detected by the operation state detection means.

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