Abnormal detection device for fuel injection device

Abstract

To detect an abnormality in a fuel injection device without requiring an intake air amount and a value influenced by the intake air amount.SOLUTION: A CPU executes a first integration process. In the first integration process, the CPU calculates an integrated consumption amount CV. The integrated consumption amount CV is the integrated value of a consumption amount of fuel supplied from a fuel tank to a fuel injection device within a specified period RT. The CPU executes a second integration process. In the second integration process, the CPU calculates an integrated requirement amount DV. The integrated requirement amount DV is the integrated value of a required amount of fuel to be injected from the fuel injection device into a combustion chamber within the specified period RT. The CPU determines whether or not a determination value JV is equal to or greater than a predetermined threshold value TH. The determination value JV is the value obtained by dividing the absolute value of a difference D, which is obtained by subtracting the integrated requirement amount DV from the integrated consumption amount CV, by the specified period RT. When the determination value JV is equal to or greater than the threshold value TH (S14: YES), the CPU performs a detection process to detect an abnormality in the fuel injection device.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an abnormality detection device for a fuel injection device.

Background Art

[0002] Patent Document 1 describes a fuel injection device that supplies fuel to a combustion chamber of an internal combustion engine and a control device for the internal combustion engine. The control device for the internal combustion engine in Patent Document 1 performs feedback control on the required injection amount from the fuel injection device so that the air-fuel ratio detected by the air-fuel ratio sensor becomes the target air-fuel ratio. When the required injection amount is equal to or greater than the allowable value, the control device performs abnormality detection based on the correction value in the feedback control.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In an internal combustion engine as described in Patent Document 1, an abnormality may occur in the operation of the throttle valve due to deterioration or the like of the throttle valve that adjusts the intake air amount. In addition, foreign substances such as deposits may accumulate in the intake passage for sucking outside air into the internal combustion engine, causing an abnormality in the intake passage. In these cases, even if there is no abnormality in the fuel injection device itself, the value of the air-fuel ratio sensor may become an abnormal value. Therefore, in the technique described in Patent Document 1, there is a risk of erroneously detecting an abnormality in the fuel injection device even though the throttle valve or the like is in an abnormal state. Therefore, a technique for detecting an abnormality in the fuel injection device without necessarily requiring the intake air amount and the value of the air-fuel ratio affected by it is desired.

Means for Solving the Problems

[0005] In order to solve the above problems, the present invention is an abnormality detection device for a fuel injection device that supplies fuel to a combustion chamber of an internal combustion engine, which includes: a first integration process for calculating, within a predetermined specified period, an integrated value of the consumption amount of fuel supplied from a fuel tank to the fuel injection device as a consumption integrated amount; a second integration process for calculating, within the specified period, an integrated value of the required injection amount injected from the fuel injection device into the combustion chamber as a required integrated amount; and a detection process for detecting an abnormality of the fuel injection device when, when an absolute value of a difference obtained by subtracting the required integrated amount from the consumption integrated amount is divided by the specified period and the resulting value is a determination value, the determination value is equal to or greater than a predetermined threshold value.

[0006] According to the above configuration, the determination value is calculated from the consumption integrated amount and the required integrated amount. And the difference between the consumption integrated amount and the required integrated amount is not affected by the magnitude of the intake air amount. Therefore, even if an abnormality occurs in a throttle valve or the like that adjusts the intake air amount and the intake air amount fluctuates, the abnormality of the fuel injection device will not be detected due to this. On the other hand, the difference between the consumption integrated amount and the required integrated amount is affected by an abnormality in the fuel injection device and the fuel supply path to the fuel injection device. Therefore, it is possible to detect an abnormality of the fuel injection device without requiring the intake air amount and values affected by it.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0008] (One Embodiment) Hereinafter, an embodiment of the abnormality detection device for a fuel injection device will be described with reference to FIGS. 1 and 2.

[0009] <Overview of the Internal Combustion Engine> As shown in FIG. 1, the internal combustion engine 10 includes a cylinder block 11, a cylinder head 12, a piston 13, and a cylinder 14. The cylinder 14 is a cylindrical space partitioned inside the cylinder block 11. Both sides in the axial direction of the cylinder 14 are open to the outside of the cylinder block 11. The piston 13 is disposed in the cylinder 14. The top surface of the piston 13 faces the first end in the axial direction of the cylinder 14. The cylinder head 12 is connected to the cylinder block 11. The outer surface of the cylinder head 12 has a recess 15. The recess 15 faces the cylinder 14 in the axial direction of the cylinder 14. The wall surface of the cylinder block 11 partitioning the cylinder 14, the wall surface of the recess 15, and the top surface of the piston 13 partition a combustion chamber R.

[0010] The internal combustion engine 10 further includes a connecting rod 16 and a crankshaft 17. The connecting rod 16 is connected to the piston 13. The connecting rod 16 extends in a direction opposite to the cylinder head 12 with the piston 13 interposed therebetween. The crankshaft 17 is connected to the connecting rod 16. The crankshaft 17 and the connecting rod 16 convert the reciprocating motion of the piston 13 into a rotational motion.

[0011] The cylinder head 12 has an intake port 18. The intake port 18 is a space partitioned inside the cylinder head 12. The first end of the intake port 18 opens toward the recess 15. The second end of the intake port 18 opens toward the outside of the cylinder head 12.

[0012] The cylinder head 12 has an exhaust port 19. The exhaust port 19 is a space partitioned inside the cylinder head 12. The first end of the exhaust port 19 opens toward the recess 15. The second end of the exhaust port 19 opens toward the outside of the cylinder head 12.

[0013] The internal combustion engine 10 includes an intake valve 20 and an exhaust valve 21. The intake valve 20 is a valve that opens and closes the first end of the intake port 18. The exhaust valve 21 is a valve that opens and closes the first end of the exhaust port 19.

[0014] In addition, in FIG. 1, only one set of the combustion chamber R, the intake port 18 and the exhaust port 19 connected to the combustion chamber R is shown, but the internal combustion engine 10 includes a plurality of sets of the combustion chamber R, the intake port 18 and the exhaust port 19 connected to the combustion chamber R, etc.

[0015] The internal combustion engine 10 includes an intake passage 31 for inhaling outside air. The intake passage 31 is connected to the second end of the intake port 18. The intake passage 31 houses a throttle valve 32. The throttle valve 32 adjusts the intake air amount GA, which is the flow rate of air flowing through the intake passage 31, by changing the valve opening degree. The air inhaled from the intake passage 31 flows into the combustion chamber R through the intake port 18.

[0016] The internal combustion engine 10 includes a fuel injection device 33. The fuel injection device 33 is attached to the cylinder head 12. Therefore, the fuel injection device 33 is located in a portion downstream of the throttle valve 32 in the intake passage 31. The fuel injection device 33 injects fuel into the intake port 18. Thereby, the fuel injection device 33 supplies fuel to the combustion chamber R.

[0017] The internal combustion engine 10 includes a spark plug 35. The spark plug 35 is attached to the cylinder head 12. The spark plug 35 is located between the intake port 18 and the exhaust port 19. The spark plug 35 ignites the air-fuel mixture introduced into the combustion chamber R by a spark.

[0018] The internal combustion engine 10 includes an exhaust passage 41, which is a discharge path for exhaust gas generated by combustion in the combustion chamber R. The exhaust passage 41 is connected to the second end of the exhaust port 19. The exhaust passage 41 houses an exhaust purification catalyst 42. The exhaust purification catalyst 42 purifies, for example, carbon monoxide and nitrogen oxides in the exhaust gas.

[0019] Further, the internal combustion engine 10 includes a fuel supply device 50. The fuel supply device 50 includes a fuel tank 51, a fuel supply passage 52, and a fuel pump 53. The fuel tank 51 is a tank that stores fuel. The first end of the fuel supply passage 52 is located inside the fuel tank 51. Also, the second end of the fuel supply passage 52 is connected to the fuel injection device 33. And the fuel pump 53 is located in the middle of the fuel supply passage 52. The fuel pump 53 pumps up fuel from the fuel tank 51 and supplies it to the fuel injection device 33.

[0020] The internal combustion engine 10 includes a crank angle sensor 91. The crank angle sensor 91 is located near the crankshaft 17. The crank angle sensor 91 detects the rotational phase SC of the crankshaft 17.

[0021] The internal combustion engine 10 includes an air flow meter 92. The air flow meter 92 is located upstream of the throttle valve 32 in the intake passage 31. The air flow meter 92 detects the intake air amount GA, which is the flow rate of the air flowing through the intake passage 31.

[0022] The internal combustion engine 10 includes a fuel flow sensor 93. The fuel flow sensor 93 is located in the fuel supply passage 52. The fuel supply passage 52 detects the fuel flow rate FA, which is the flow rate of the fuel flowing through the fuel supply passage 52. Note that the fuel flow rate FA is the consumption amount of the fuel supplied from the fuel tank 51 to the fuel injection device 33 per unit time.

[0023] The vehicle equipped with the internal combustion engine 10 includes a control device 100. The control device 100 targets the internal combustion engine 10 for control. The control device 100 acquires a signal indicating the rotational phase SC of the crankshaft 17 from the crank angle sensor 91. The control device 100 acquires a signal indicating the intake air amount GA from the air flow meter 92. The control device 100 acquires a signal indicating the fuel flow rate FA from the fuel flow sensor 93.

[0024] The control device 100 includes a CPU 101, a peripheral circuit 102, a ROM 103, a storage device 104, and a bus 105. The bus 105 communicably connects the CPU 101, the peripheral circuit 102, the ROM 103, and the storage device 104 to each other. The peripheral circuit 102 includes a circuit that generates a clock signal for defining internal operations, a power supply circuit, a reset circuit, and the like. The ROM 103 stores in advance various programs for the CPU 101 to execute various controls. The CPU 101 controls the fuel injection device 33 of the internal combustion engine 10 by executing various programs stored in the ROM 103. In particular, the ROM 103 stores an abnormality detection program for detecting an abnormality of the fuel injection device 33. Further, the CPU 101 stores the detected and calculated values in the storage device 104 as time-series data for a predetermined period. Then, the control device 100 functions as an abnormality detection device for the fuel injection device 33.

[0025] Taking the fuel injection device 33 as a control target, the control device 100 executes injection control processing. In the injection control processing, first, the CPU 101 calculates a required injection amount, which is the amount of fuel used for one combustion. The CPU 101 calculates the required injection amount based on the engine load and the engine rotational speed. In this embodiment, as the engine load, a value obtained by dividing the intake air amount GA by the engine rotational speed is used. The CPU 101 calculates the engine rotational speed based on the rotational phase SC acquired from the crank angle sensor 91.

[0026] When the internal combustion engine 10 is driving, the CPU 101 repeatedly executes the abnormality detection program stored in the ROM 103 at a predetermined frequency.

[0027] As shown in FIG. 2, when the CPU 101 starts the abnormality detection program, it first performs the process of step S11. In step S11, the CPU 101 performs the first integration process. In the first integration process, the CPU 101 calculates the consumption integrated amount CV. The consumption integrated amount CV is the integrated value of the consumption amount of the fuel supplied from the fuel tank 51 to the fuel injection device 33 within a predetermined regular period RT. Specifically, the CPU 101 sets the time period from the current time to a time a predetermined fixed time before as the regular period RT. Then, the CPU 101 refers to the time-series data of the fuel flow rate FA stored in the storage device 104, integrates the fuel flow rate FA within the regular period RT, and sets this as the consumption integrated amount CV. After that, the CPU 101 advances the process to step S12.

[0028] In step S12, the CPU 101 performs the second integration process. In the second integration process, the CPU 101 calculates the required integrated amount DV. The required integrated amount DV is the integrated value of the required fuel amount injected from the fuel injection device 33 into the combustion chamber R within the regular period RT. Specifically, the CPU 101 refers to the time-series data of the required injection amount stored in the storage device 104, integrates the required injection amount within the regular period RT, and sets this as the required integrated amount DV. Note that the regular period RT in step S12 is the same time as the regular period RT in step S11. After that, the CPU 101 advances the process to step S13.

[0029] In step S13, the CPU 101 performs the determination value calculation process. In the determination value calculation process, the CPU 101 calculates the determination value JV. The determination value JV is the value obtained by dividing the absolute value of the difference D obtained by subtracting the required integrated amount DV from the consumption integrated amount CV by the regular period RT. Specifically, the CPU 101 subtracts the required integrated amount DV from the consumption integrated amount CV to calculate the difference D. Next, the CPU 101 divides the absolute value of the difference D by the regular period RT to calculate the determination value JV. Therefore, the determination value JV is always a positive value. After that, the CPU 101 advances the process to step S14.

[0030] In step S14, the CPU 101 determines whether the determination value JV is equal to or greater than a predetermined threshold TH. The threshold TH is a value determined in advance through tests or simulations as the absolute value of the difference D when the fuel injection device 33 is in a state where it no longer functions properly due to deterioration or the like, that is, in an abnormal state, divided by a specified period RT. When the determination value JV is less than the threshold TH (S14: NO), the CPU 101 ends the current series of processes. On the other hand, when the determination value JV is equal to or greater than the threshold TH (S14: YES), the CPU 101 advances the process to step S15.

[0031] In step S15, the CPU 101 performs a detection process. In the detection process, the CPU 101 detects an abnormality in the fuel injection device 33. Specifically, the state parameter of the fuel injection device 33 stored in the storage device 104 is set to a state indicating an abnormal state. Thereafter, the CPU 101 ends the current series of processes.

[0032] When the state parameter of the fuel injection device 33 stored in the storage device 104 becomes a state indicating an abnormal state, the CPU 101, for example, gives a warning indicating the abnormal state to the user. Specifically, a message indicating the abnormal state is displayed on the display of the vehicle on which the internal combustion engine 10 is mounted. When the fuel injection device 33 is replaced or the like by a dealer or the like, the state parameter of the fuel injection device 33 stored in the storage device 104 is changed to a state indicating a normal state.

[0033] (Operation of the Embodiment) According to the above embodiment, due to deterioration or the like, the fuel injection device 33 may inject more fuel or less fuel than expected. In this case, the determination value JV becomes a larger value as the fuel injection device 33 deteriorates. When an affirmative determination is made in step S14, that is, when the determination value JV is equal to or greater than the threshold TH, the CPU 101 performs a detection process.

[0034] (Effect of the Embodiment) According to the above embodiment, the determination value JV is calculated from the consumption integrated amount CV and the required integrated amount DV. And the difference D between the consumption integrated amount CV and the required integrated amount DV is not affected by the magnitude of the intake air amount GA. Therefore, even if an abnormality occurs in the throttle valve 32 that adjusts the intake air amount GA and the intake air amount GA fluctuates, an abnormality in the fuel injection device 33 will not be detected due to this. Also, even if foreign substances such as deposits accumulate in the intake passage 31, an abnormality occurs in the intake passage 31, and the intake air amount GA fluctuates, an abnormality in the fuel injection device 33 will not be detected due to this. On the other hand, the difference D between the consumption integrated amount CV and the required integrated amount DV is affected by an abnormality in the fuel injection device 33 and the fuel supply passage 52 to the fuel injection device 33. Therefore, an abnormality in the fuel injection device 33 can be detected without requiring the intake air amount GA and values affected by it.

[0035] (Other Embodiments) The above embodiment can be implemented with the following modifications. The above embodiment and the following modification examples can be implemented in combination with each other within a technically non - conflicting range.

[0036] · The method of calculating the determination value JV is not limited to the example of the above embodiment. For example, it may be calculated by subtracting the value obtained by dividing the required integrated amount DV by the specified period RT from the value obtained by dividing the consumption integrated amount CV by the specified period RT.

[0037] · The method of calculating the consumption integrated amount CV is not limited to the example of the above embodiment. For example, assuming that a mass sensor that measures the weight of the fuel stored in the fuel tank 51 detects the mass of the fuel. At this time, the change amount of the mass of the fuel detected by the mass sensor within the specified period RT may be calculated as the consumption integrated amount CV.

[0038] · When the determination value JV is less than the threshold value TH, the life of the fuel injection device 33 may be estimated based on the difference D between the determination value JV and the threshold value TH. In this modification example, the smaller the difference D between the determination value JV and the threshold value TH, the shorter the life of the fuel injection device 33 may be estimated.

[0039] · When the determination value JV is less than the threshold value TH and the absolute value of the difference D between the determination value JV and the threshold value TH exceeds a certain value, it may be possible to alert the vehicle user. · The fuel injection device 33 is not limited to a device that injects fuel into the intake port 18. For example, the fuel injection device 33 may be a device that directly injects fuel into the combustion chamber R.

[0040] · The abnormality detection device for the fuel injection device 33 may be a device separate from the control device 100 of the internal combustion engine 10.

Description of Signs

[0041] 10…Internal combustion engine 33…Fuel injection device 51…Fuel tank CV…Consumption integrated amount D…Difference DV…Required integrated amount JV…Determination value R…Combustion chamber RT…Specified period TH…Threshold value

Claims

【Claim 1】 An abnormality detection device for a fuel injection device that supplies fuel to a combustion chamber of an internal combustion engine, a first integration process that calculates, as an integrated consumption amount, an integrated value of the consumption amount of fuel supplied from a fuel tank to the fuel injection device within a predetermined specified period; a second integration process that calculates, as a required integrated amount, an integrated value of a required injection amount injected from the fuel injection device into the combustion chamber within the specified period; a detection process for detecting an abnormality of the fuel injection device when, when an absolute value of a difference obtained by subtracting the required integrated amount from the integrated consumption amount is divided by the specified period and the resulting value is a determination value, the determination value is equal to or greater than a predetermined threshold value; executing An abnormality detection device for a fuel injection device.

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