JP5821566B2 - Abnormality detection apparatus for internal combustion engine - Google Patents

Description

  The present invention relates to a misfire abnormality detection device for an internal combustion engine comprising an in-cylinder injector that injects fuel into a cylinder and an intake passage injector that injects fuel into an intake passage (intake port). About.

  As an internal combustion engine (engine) mounted on a vehicle or the like, an in-cylinder injector for injecting fuel into a cylinder, and an intake passage injection for injecting fuel into an intake passage (intake port) 2. Description of the Related Art A so-called dual-injection internal combustion engine that includes an injector is known. In such a dual injection type internal combustion engine, for example, stratified combustion in a low load operation region and homogeneous combustion in a high load operation region can be performed by switching two injectors according to the operating state of the engine. Can be realized. Further, fuel efficiency characteristics and output characteristics can be improved by adjusting the injection ratio (injection ratio) between the in-cylinder injector and the intake manifold injector.

  In such an internal combustion engine, for example, detection of misfire abnormality and normal return from the abnormality are performed. As an example of the misfire abnormality detection process, in addition to the engine speed, engine load (load factor), and warm-up state when the count number of the misfire counter exceeds a predetermined value, the injection state (port injection, in-cylinder injection) , Dual injection) is stored, and normal return determination is performed under conditions similar to the stored engine operation state and injection state (see, for example, Patent Document 1). According to such a misfire abnormality detection method (prior art), in addition to the engine operating state (engine speed, engine load (load factor), warm-up state), the injection state is also stored as a condition. Although the state is different, it is possible to reduce the normal return.

JP 2011-026961 A

  By the way, in the above-described misfire abnormality detection method, when the count number of the misfire counter becomes equal to or larger than a predetermined value, the engine operation state and the injection state are simply stored. There may be a deviation from the engine operating state where misfire has occurred. For example, it may be stored that the injection state in which the misfire has occurred is the dual injection state although the engine operating state in which the misfire has occurred is the in-cylinder injection state. In such a situation, there is a case where normal return determination cannot be performed properly.

  The present invention has been made in view of such circumstances, and includes an in-cylinder injector that injects fuel into the cylinder, and an intake-path injector that injects fuel into the intake passage. Another object of the present invention is to provide an internal combustion engine including a misfire detection device capable of storing an abnormal operation state in accordance with an injection state when a misfire occurs.

The present invention includes an in-cylinder fuel injection valve that directly injects fuel into a combustion chamber, and an intake passage fuel injection valve that injects fuel into an intake passage, and one of a plurality of injection states having different injection ratios. This presupposes a misfire abnormality detection device for an internal combustion engine that can be selectively switched to one injection state. In such a misfire abnormality detection device, the operation state and the injection state of the internal combustion engine at the time of the misfire are stored, the abnormality operation state is obtained for each of the plurality of injection states, and within a predetermined period. in misfire determines the abnormal injection state based on a predetermined condition from among a plurality of injection state when that occurred and the determined abnormal injection-shaped on purpose, the abnormal operation state in the abnormal injection state It is characterized by memorizing it in association.

  In the present invention, the normal return determination is performed when the injection state is the same as the abnormal injection state determined by the processing, and when the abnormal operation state stored by the processing is similar. The similar operation state is an engine operation state that is the same as the abnormal operation state stored by the processing or an engine operation state that is within a predetermined range that is set in advance with respect to the abnormal operation state. .

  According to the present invention, it is possible to memorize the abnormal operation state in accordance with the injection state when the misfire has occurred. Therefore, when performing the normal return determination after detecting the misfire abnormality, the normal return determination is appropriately performed. It can be carried out.

  Here, in the present invention, the plurality of injection states having different injection ratios include, for example, an injection state in which fuel is injected only by the in-cylinder fuel injection valve (DI injection), and fuel by only the intake passage fuel injection valve. Examples include an injection state (PFI injection) in which fuel is injected, and an injection state (DUAL injection) in which fuel is injected by the in-cylinder fuel injection valve and the intake passage fuel injection valve.

  In the present invention, as a specific method for determining the above-described abnormal injection state, the number of misfires for each injection state that occurs within a predetermined period (detection period of misfire abnormality: see FIG. 8) ( Specifically, a method of determining based on a misfire counter count value for each injection state can be mentioned.

  In this case, for example, the injection state with the largest number of misfires within a predetermined period may be determined as the abnormal-time injection state. Further, for example, when the plurality of injection states having different injection ratios are three forms of DUAL injection, DI injection, and PFI injection, if the number of misfires in the DUAL injection is equal to or greater than a predetermined determination value, the DUAL injection Is determined as an abnormal injection state (DUAL abnormality). On the other hand, if the number of misfires in the DUAL injection is less than the judgment value, the number of misfires in the DI injection is compared with the number of misfires in the PFI injection. If the number of misfires in the DI injection is larger, the DI injection is performed. When the abnormal injection state (DI abnormality) is determined and the number of misfires in the PFI injection is larger, the PFI injection may be determined as the abnormal injection state (PFI abnormality).

  According to the present invention, it is possible to memorize the abnormal operation state in accordance with the injection state when the misfire has occurred. Therefore, when performing the normal return determination after detecting the misfire abnormality, the normal return determination is appropriately performed. It can be carried out.

It is a schematic block diagram which shows an example of the engine (internal combustion engine) to which this invention is applied. It is a block diagram which shows the structure of control systems, such as ECU. It is a figure which shows an example of the injection division ratio map of fuel injection. It is a flowchart which shows an example of the misfire abnormality detection process which ECU performs. It is a figure which shows a normal return area | region. It is a figure which shows the problem of the conventional misfire abnormality detection method. It is a flowchart which shows the other example of the misfire abnormality detection process which ECU performs. It is a figure which shows the detection period of misfire abnormality.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

-Engine-
FIG. 1 is a diagram showing a schematic configuration of an engine to which the present invention is applied. FIG. 1 shows only the configuration of one cylinder of the engine.

  The engine 1 of this example is a four-cylinder (first cylinder # 1 to fourth cylinder # 4) gasoline engine mounted on a vehicle, and reciprocates vertically in a cylinder block 1a constituting each cylinder. A moving piston 1c is provided. The piston 1c is connected to the crankshaft 15 via the connecting rod 16, and the reciprocating motion of the piston 1c is converted into rotation of the crankshaft 15 by the connecting rod 16.

  A signal rotor 17 is attached to the crankshaft 15. A plurality of teeth (projections) 17a are provided on the outer peripheral surface of the signal rotor 17 at equal angles (in this example, for example, 10 ° CA (crank excessive)). Further, the signal rotor 17 has a missing tooth portion 17b in which two teeth 17a are missing.

  A crank position sensor (engine speed sensor) 201 for detecting a crank angle is disposed near the side of the signal rotor 17. The crank position sensor 201 is, for example, an electromagnetic pickup, and generates a pulse signal (voltage pulse) corresponding to the teeth 17a of the signal rotor 17 when the crankshaft 15 rotates. The engine speed NE can be calculated from the output signal of the crank position sensor 201.

  The cylinder block 1a of the engine 1 is provided with a water temperature sensor 203 that detects the temperature of engine cooling water. A cylinder head 1b is provided at the upper end of the cylinder block 1a, and a combustion chamber 1d is formed between the cylinder head 1b and the piston 1c. A spark plug 3 is disposed in the combustion chamber 1 d of the engine 1. The ignition timing of the spark plug 3 is adjusted by the igniter 4. The igniter 4 is controlled by an ECU (Electronic Control Unit) 100.

  An oil pan 18 for storing lubricating oil (engine oil) is provided below the cylinder block 1 a of the engine 1. Lubricating oil stored in the oil pan 18 is pumped up by an oil pump (not shown) through an oil strainer that removes foreign matters during operation of the engine 1, and the engine such as the piston 1 c, crankshaft 15, connecting rod 16, etc. It is supplied to each part and used for lubrication and cooling of each part. The lubricating oil supplied in this way is used for lubrication and cooling of each part of the engine, then returned to the oil pan 18 and stored in the oil pan 18 until it is pumped up again by the oil pump. .

  An intake passage 11 and an exhaust passage 12 are connected to the combustion chamber 1 d of the engine 1. A part of the intake passage 11 is formed by an intake port 11a and an intake manifold 11b. A part of the exhaust passage 12 is formed by an exhaust port 12a and an exhaust manifold 12b.

  In the intake passage 11, an air cleaner 7 that filters intake air (fresh air), an air flow meter 204, an intake air temperature sensor 207, a throttle valve 5 for adjusting the intake air amount of the engine 1, and the like are arranged. The air flow meter 204 detects the intake air amount (new air amount). The intake air temperature sensor 207 detects the temperature of the air taken into the engine 1 (intake air temperature).

  The throttle opening of the throttle valve 5 is driven and controlled by the ECU 100. Specifically, the optimum intake air amount (in accordance with the operating state of the engine 1 such as the engine speed NE calculated from the output signal of the crank position sensor 201 and the accelerator pedal depression amount (accelerator opening) of the driver). The throttle opening of the throttle valve 5 is controlled so as to obtain a target intake air amount. More specifically, the actual throttle opening of the throttle valve 5 is detected using the throttle opening sensor 205, and the actual throttle opening coincides with the throttle opening (target throttle opening) at which the target intake air amount can be obtained. Thus, the throttle motor 6 of the throttle valve 5 is feedback controlled. Such a control system for the throttle valve 5 is referred to as an “electronic throttle system”, and it is also possible to control the throttle opening independently of the driver's accelerator pedal operation during idling operation or the like. .

  An intake valve 13 is provided between the intake passage 11 and the combustion chamber 1d. By opening and closing the intake valve 13, the intake passage 11 and the combustion chamber 1d are communicated or blocked. Further, an exhaust valve 14 is provided between the exhaust passage 12 and the combustion chamber 1d. By opening and closing the exhaust valve 14, the exhaust passage 12 and the combustion chamber 1d are communicated or blocked. The opening / closing drive of the intake valve 13 and the exhaust valve 14 is performed by each rotation of the intake camshaft 21 and the exhaust camshaft 22 to which the rotation of the crankshaft 15 is transmitted via a timing chain or the like.

  In the vicinity of the intake camshaft 21, a cam position sensor 202 is provided that generates a pulse signal when the piston 1c of a specific cylinder (for example, the first cylinder # 1) reaches the compression top dead center (TDC). ing. The cam position sensor 202 is, for example, an electromagnetic pickup, and is disposed so as to face one tooth (not shown) on the outer peripheral surface of the rotor provided integrally with the intake camshaft 21. When the shaft 21 rotates, a pulse signal (voltage pulse) is output. Since the intake camshaft 21 (and the exhaust camshaft 22) rotates at a half speed of the crankshaft 15, the cam position sensor 202 is set to 1 every time the crankshaft 15 rotates twice (720 ° rotation). Two pulse signals are generated.

  From the output signals of the cam position sensor 202 and the crank position sensor 201, the piston position (intake stroke / compression) of each cylinder (first cylinder # 1 to fourth cylinder # 4) of the engine 1 during engine operation. Stroke, explosion stroke, and exhaust stroke) can be recognized, and engine operation control such as precise fuel injection control and ignition timing control can be performed.

On the other hand, a three-way catalyst 9 is disposed in the exhaust passage 12. In the three-way catalyst 9, oxidation of CO and HC and reduction of NOx in the exhaust gas exhausted from the combustion chamber 1d to the exhaust passage 12 is performed, and these are made harmless CO ₂ , H ₂ O, and N ₂ . In this way, the exhaust gas is purified.

  An air-fuel ratio (A / F) sensor 209 is disposed in the exhaust passage 12 upstream of the three-way catalyst 9 (upstream of the exhaust flow). The air-fuel ratio sensor 209 is a sensor that exhibits linear characteristics with respect to the air-fuel ratio. An O 2 sensor 210 is disposed in the exhaust passage 12 on the downstream side of the three-way catalyst 9. The O2 sensor 210 generates an electromotive force in accordance with the oxygen concentration in the exhaust gas. When the output is higher than the voltage (comparison voltage) corresponding to the theoretical air-fuel ratio, the O2 sensor 210 determines that the output is rich, and conversely compares When the output is lower than the voltage, it is judged as lean.

<Fuel injection system>
Next, the fuel injection system of the engine 1 will be described.

  Each cylinder of the engine 1 is provided with an in-cylinder injector (in-cylinder fuel injection valve) 2a capable of directly injecting fuel into each combustion chamber 1d. These in-cylinder injectors 2a are connected to a common high-pressure fuel delivery pipe 20a.

  Further, in the intake passage 11 of the engine 1, a port injector (intake passage fuel injection valve) 2b capable of injecting fuel into each intake port 11a is disposed. The port injector 2b is provided for each cylinder. These port injectors 2b are connected to a common low pressure fuel delivery pipe 20b.

  Fuel supply to the high-pressure fuel delivery pipe 20a and the low-pressure fuel delivery pipe 20b is performed by a feed pump 301 and a high-pressure pump 302 as low-pressure pumps. The feed pump 301 pumps up fuel (gasoline etc.) in the fuel tank 300 and supplies it to the delivery pipe 20b for low pressure fuel and the high pressure pump 302. The high pressure pump 302 pressurizes the low pressure fuel from the feed pump 301 and supplies it to the high pressure fuel delivery pipe 20a.

  The in-cylinder injector 2a is an electromagnetically driven on-off valve that opens when a predetermined voltage is applied and injects fuel directly into the combustion chamber 1d. The opening / closing (injection time / injection timing) of the in-cylinder injector 2a is duty-controlled by the ECU 100.

  Similarly, the port injector 2b is an electromagnetically driven on-off valve that opens when a predetermined voltage is applied and injects fuel into the intake port 11a. The port injection injector 2b is also duty-controlled by the ECU 100 for opening and closing (injection time / injection timing).

  The injection ratio (PFI injection ratio: KPFI) between the fuel injection (DI injection) by the in-cylinder injector 2a and the fuel injection (PFI injection) by the port injector 2b will be described later.

  An air-fuel mixture (fuel + air) is formed in the combustion chamber 1b by fuel injection from one or both of the in-cylinder injector 2a and the port injector 2b. This air-fuel mixture is ignited by the spark plug 3 and burns and explodes. The piston 1c is reciprocated by the high-temperature and high-pressure combustion gas generated at this time, the crankshaft 15 is rotated, and the driving force (output torque) of the engine 1 is obtained. The combustion gas burned in the combustion chamber 1d is discharged to the exhaust passage 12 when the exhaust valve 14 is opened.

-ECU-
As shown in FIG. 2, the ECU 100 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, a backup RAM 104, a misfire counter 110, a detection period counter 120, and the like. ing.

  The ROM 102 stores various control programs, maps that are referred to when the various control programs are executed, and the like. The CPU 101 executes various arithmetic processes based on various control programs and maps stored in the ROM 102. The RAM 103 is a memory that temporarily stores calculation results of the CPU 101, data input from each sensor, and the like. The backup RAM 104 is a nonvolatile memory that stores data to be saved when the engine 1 is stopped, for example. Memory.

  The detection period counter 120 is a counter that measures the cumulative number of revolutions (Rev) of the engine 1. When the count value of the detection period counter 120 reaches, for example, 1000 Rev, one misfire detection period (FIG. 8). End).

  As will be described later, the misfire counter 110 is a total misfire counter that counts up (increments) by one each time the rotational fluctuation amount ΔNE of each cylinder # 1 to # 4 of the engine 1 exceeds the misfire determination threshold. A misfire-time dual counter, a misfire-time DI counter, and a misfire-time PFI counter are provided for counting the number of misfires for each injection state (DUAL injection, DI injection, PFI injection). In the misfire counter 110 of this example, when a misfire occurs during the detection period shown in FIG. 8, every time the misfire occurs, the count value of the total misfire counter is incremented by one. The count value of the misfire-time DUAL counter, the misfire-time DI counter, or the misfire-time PFI counter is incremented by one according to the injection state.

  The CPU 101, the ROM 102, the RAM 103, the backup RAM 104, the misfire counter 110, and the detection period counter 120 are connected to each other via the bus 107, and are connected to the input interface 105 and the output interface 106.

  The input interface 105 includes a crank position sensor (engine speed sensor) 201, a cam position sensor 202, a water temperature sensor 203, an air flow meter 204, a throttle opening sensor 205, and an accelerator that outputs a detection signal corresponding to the depression amount of the accelerator pedal. An opening sensor 206, an intake air temperature sensor 207, an intake manifold pressure sensor 208, an air-fuel ratio sensor 209, an O2 sensor 210, a high-pressure fuel pressure sensor 211 for detecting the pressure (fuel pressure) of high-pressure fuel supplied to the in-cylinder injector 2a, Various sensors such as a low-pressure fuel fuel pressure sensor 212 for detecting the pressure (fuel pressure) of the low-pressure fuel supplied to the port injector 2b are connected. Further, an ignition switch 213 is connected to the input interface 105, and when the ignition switch 213 is turned on (IG-ON), cranking of the engine 1 by a starter motor (not shown) is started.

  In-cylinder injector 2a, port injector 2b, igniter 4 of spark plug 3, and throttle motor 6 of throttle valve 5 are connected to output interface 106.

  Then, the ECU 100 controls the following fuel injection amount control, ignition timing control of the ignition plug 3, and drive control (intake air amount control) of the throttle motor 6 of the throttle valve 5 based on the detection signals of the various sensors described above. Various controls of the engine 1 including the above are executed. Further, the ECU 100 executes the following “misfire detection process” and “misfire abnormality detection process”.

  The internal combustion engine (engine) misfire detection apparatus of the present invention is realized by the program executed by the ECU 100 described above.

-Fuel injection amount control-
First, the ROM 102 of the ECU 100 stores an injection ratio map shown in FIG.

  The injection ratio map shown in FIG. 3 is an experiment of fuel injection mode in consideration of fuel consumption (fuel consumption rate) characteristics and output characteristics using the engine speed NE and the load ratio KL indicating the operating state of the engine 1 as parameters. The maps are adapted by simulation or the like, and the DI region (direct injection region) in which fuel is injected only by the in-cylinder injector 2a, and the PFI region (port injection region) in which fuel is injected only by the port injector 2b. In addition, a dual region (direct injection and port injection region (PFI + DI)) in which fuel is injected by the in-cylinder injector 2a and the port injector 2b is set.

  The ECU 100 refers to the map of FIG. 3 based on the engine speed NE and the engine load factor KL obtained from the output signal of the crank position sensor 201, and determines the fuel injection ratio (injection from the port injector 2b). The fuel injection ratio KPFI (%)) is calculated, and the fuel injection is executed by calculating the injection time and the injection timing based on the injection ratio KPFI and the required injection amount.

  Specifically, when the engine operating state (engine speed NE / load factor KL) is in the DI region (injection ratio KPFI = 0%), the DI required injection amount and the output signal of the fuel pressure sensor 211 for high-pressure fuel Based on the obtained fuel pressure and the capacity (flow rate size) of the in-cylinder injector 2a, the DI injection time and DI injection timing of the high-pressure fuel injected from the in-cylinder injector 2a are calculated, and the calculated DI injection Based on the time and DI injection timing, the in-cylinder injector 2a is controlled to open and close to perform fuel injection.

  When the engine operation state (engine speed NE / load factor KL) is in the PFI region (injection ratio KPFI = 100%), the PFI required injection amount, the fuel pressure obtained from the output signal of the low-pressure fuel pressure sensor 212, and The PFI injection time and the PFI injection timing of the low-pressure fuel injected from the port injector 2b are calculated based on the capacity (flow rate size) of the port injector 2b, and the calculated PFI injection time and PFI injection timing are calculated. Based on this, the port injection injector 2b is controlled to open and close to perform fuel injection.

  When the engine operating state (engine speed NE / load factor KL) is in the DUAL region (0% <split distribution ratio KPFI <100%), the DI required injection of the in-cylinder injector 2a based on the spray split ratio KPFI The amount (total required injection amount × (1−injection ratio KPFI / 100)) and the PFI required injection amount of the port injector 2b (total required injection amount × injection ratio KPFI / 100) are obtained and the same as above. Thus, the DI injection time and DI injection timing, and the PFI injection time and PFI injection timing are calculated. The in-cylinder injector 2a is controlled to open and close based on the calculated DI injection time and DI injection timing, and the port injection injector 2b is controlled to open and close based on the calculated PFI injection time and PFI injection timing. Perform injection.

  Here, the required injection amount is the amount of fuel in which the air-fuel ratio of the air-fuel mixture combusted in the engine 1 becomes the stoichiometric air-fuel ratio, and is, for example, in the engine operating state (engine speed NE and engine load factor KL). Based on this, it can be calculated using a map or the like. Further, the engine load factor KL uses a map or the like based on, for example, the engine rotational speed NE, the intake air amount obtained from the output signal of the air flow meter 204, the throttle opening obtained from the output signal of the throttle opening sensor 205, and the like. Can be calculated.

-Misfire detection processing-
Next, misfire detection processing executed by the ECU 100 will be described.

  First, when a misfire occurs in a cylinder (for example, the first cylinder # 1) among the four cylinders # 1 to # 4 of the engine 1, the engine rotation in the explosion stroke of the cylinder (including a plurality of cylinders) Since the speed decreases, the time required for the crankshaft 15 to rotate at a constant crank angle during the explosion stroke of the cylinder (first cylinder # 1) in which this misfire has occurred is determined by other cylinders (for example, the second cylinder # 2). ~ It becomes longer than the time during the explosion stroke of the fourth cylinder # 4). Therefore, it is possible to recognize the occurrence of misfire by measuring and comparing these times.

  An example of the specific processing will be described.

  First, the ECU 100 takes in the output signals of the crank position sensor (engine speed sensor) 201 and the cam position sensor 202 at every predetermined crank angle (for example, every 30 ° CA), and based on these signals, the first When the cylinder # 1 is in the explosion stroke, the elapsed time T1 required for the crankshaft 15 to rotate at a constant crank angle (for example, 180 ° CA) during the explosion stroke, and the explosion stroke of the first cylinder # 1 Elapsed time required for the crankshaft 15 to rotate at a certain crank angle (for example, 180 ° CA) during the explosion stroke of the second cylinder # 2 that has reached the explosion stroke one time before (360 ° CA). The difference from T2 is calculated to obtain the rotation fluctuation amount ΔNE1 (= T1−T2) of the first cylinder # 1.

  Similarly, the elapsed time T3 (third cylinder # 3) required for the crankshaft 15 to rotate at a constant crank angle (for example, 180 ° CA) during the explosion stroke of the cylinders # 2 to # 4 of the engine 1 is the same. , T4 (fourth cylinder # 4), T2 (second cylinder # 2) are sequentially calculated, and the third cylinder # 3 rotational fluctuation amount ΔNE3 (= T3−T1), the fourth cylinder # 4 rotational fluctuation amount. ΔNE4 (= T4-T3) and the rotational fluctuation amount ΔNE2 (= T2-T4) of the second cylinder # 2 are obtained.

  Then, the ECU 100 compares the rotational fluctuation amounts ΔNE1 to ΔNE4 of the cylinders # 1 to # 4 obtained by the above calculation with the misfire determination threshold value, and when there is a cylinder in which the rotational fluctuation amount ΔNE exceeds the misfire determination threshold value. Determine that a misfire has occurred. Each time the rotational fluctuation amount ΔNE exceeds the misfire determination threshold, the misfire counter (total misfire counter) 110 provided in the ECU 100 is incremented by one.

  Here, the misfire determination threshold value set with respect to the rotational fluctuation amount ΔNE is a value that is empirically adapted based on the result obtained by experimentally / simulating the rotational fluctuation amount of the engine 1 in which misfire occurs. is there. This misfire determination threshold value is stored in the ROM 102 of the ECU 100. Further, the misfire determination threshold value may be variably set according to the rotational fluctuation amount ΔNE or the like. The rotational fluctuation amount of each cylinder # 1 to # 4 may be recognized (calculated) by other known methods.

Further, the method of detecting misfire of the engine 1 is not limited to the method of detecting misfire using the rotation fluctuation amount of the engine 1 described above. For example, an air-fuel ratio sensor and O ₂ arranged before and after the catalyst are used. Other known methods such as a method of detecting the occurrence of misfire based on an output signal (difference between two sensor detection values) with a sensor (oxygen sensor) may be adopted.

-Misfire detection process-
First, as described above, in the conventional misfire abnormality detection method, when the count number of the misfire counter becomes a predetermined value or more, the engine operation state and the injection state are merely stored. In some cases, the memorized injection state and the engine operation state where the misfire has actually occurred (operation state at the time of abnormality) deviate. For example, as shown in FIG. 6, the abnormal injection state is stored as the dual injection state even though the abnormal operation state where the misfire has occurred is a point in the PFI region (port injection region). There is. In such a situation, the area that simultaneously satisfies the dual area and the normal determination area (hatched area in the figure) becomes narrow, so that it is difficult to determine whether the normal state is restored.

  In order to eliminate such a point, in this embodiment, it is made possible to memorize the abnormal operation state in accordance with the operation state when the misfire abnormality occurs.

  An example of the specific process (misfire abnormality detection process) will be described with reference to the flowchart of FIG. The processing routine of FIG. 4 is repeatedly executed in the ECU 100, for example, every several milliseconds.

  Here, the target operating states in the present embodiment are the engine speed NE, the load factor KL, and the warm-up state. Further, the warm-up state is set to one of a cold state (a state where the water temperature is lower than the warm-up temperature (for example, 80 ° C.)) and a high temperature (a state where the water temperature is equal to or higher than the warm-up temperature).

  In the present embodiment, the detection period counter 120 in the ECU 100 starts counting from the time when the control routine of FIG. 4 is started (counted in another routine), and the engine 1 (crankshaft 15) rotates once. Every time (1 Rev) is performed, the count value of the detection period counter 120 is incremented by one. ECU 100 recognizes the rotational speed of engine 1 based on the output signal of crank position sensor 201.

  When the control routine of FIG. 4 is started, first, in step ST101, it is determined whether or not the count value of the misfire counter (total misfire counter) 110 has been increased.

  When the determination result in step ST101 is negative (NO) (when the misfire counter 110 is not counted up), the process returns. When the determination result of step ST101 is affirmative (YES) (when the misfire counter 110 is counted up), the process proceeds to step ST102.

  In step ST102, it is determined whether or not the abnormal-time injection state when a misfire occurs (when the misfire counter 110 is counted up) is a dual injection (dual abnormality). If the determination result is affirmative (YES), the process proceeds to step ST103. In the case of a dual failure, the misfire counter 110 count value of the misfire counter 110 is incremented.

  In step ST103, the operation state at the time of DUAL abnormality is updated. Thereafter, the process proceeds to step ST105. The abnormality-time operation state update process executed in step ST102 will be specifically described for each operation state (engine speed NE, load factor KL, warm-up state).

(Engine speed NE)
The engine speed NE is updated by the following formula (1) for the engine speed NE when the misfire is abnormal (when the misfire counter 110 is counted up) (update) Value).

NE (i) = (NE (i-1) + NE (i)) / 2 (1)
In this equation (1), NE (i) is the engine speed at the time of this misfire abnormality (dual abnormality), and NE (i-1) is the engine speed at the time of the previous misfire abnormality (dual abnormality). .

  When the above equation (1) is used, for example, when the engine speed NE at the time of the previous misfire abnormality is 1200 rpm, and the engine speed NE at the time of the current misfire abnormality is 1400 rpm, the engine speed NE The update value is 1300 rpm, and when the engine speed NE at the next misfire abnormality is 1600 rpm, the update value of the engine speed NE at that time is 1450 rpm.

(Load factor KL)
The load factor KL at the time of misfire abnormality (when the misfire counter 110 is counted up) is subjected to a smoothing process (1/2 smoothing process) according to the following formula (2) to update the load factor KL (update value) calculate).

KL (i) = (KL (i-1) + KL (i)) / 2 (2)
In this equation (2), KL (i) is a load factor at the time of the current misfire abnormality (dual abnormality), and KL (i-1) is a load factor at the time of the previous misfire abnormality (dual abnormality).

  When the above formula (2) is used, for example, when the load factor KL at the time of the previous misfire abnormality is 30% and the load factor KL at the time of the current misfire abnormality is 40%, the load factor KL is updated. The value is 35%, and when the load factor KL at the time of the next misfire abnormality is 45%, the updated value of the load factor KL at that time is 40%.

(Warm-up state)
The warm-up state when the misfire is abnormal (when the misfire counter 110 is counted up) is sequentially updated to the latest state (cold or high temperature). For example, if the warm-up state at the previous misfire abnormality (dual abnormality) is high temperature and the warm-up state at the current misfire abnormality (dual abnormality) is cold, the warm-up state is set to “ Update to “when cold”. In addition, instead of such update processing, if a misfire abnormality (dual abnormality) occurs even at least once during the detection period (see FIG. 8), the update value of the warm-up state is set to “cold”. It may be fixed at “time”.

  If the determination result of step ST102 is negative (NO), the process proceeds to step ST104. In step ST104, it is determined whether or not the abnormality injection state is DI injection (DI abnormality) when a misfire occurs (when the misfire counter 110 is counted up). If the determination result is affirmative (YES), the process proceeds to step ST113. When the DI is abnormal, the misfire counter 110 count value of the misfire counter 110 is incremented.

  In step ST113, the operation state at the time of DI abnormality is updated by the process similar to step ST103 mentioned above. That is, the engine speed NE and the load factor KL at the time of misfire abnormality (when DI is abnormal) are subjected to a smoothing process according to the above formulas (1) and (2), and the engine speed NE at the time of DI abnormality and Update the load factor KL. In addition, the warm-up state at the time of DI abnormality is updated to the latest state (cold or high temperature) (or if there is a cold abnormality during the detection period, the warm-up state is fixed during cold. ). After performing this update process, the process proceeds to step ST105.

  If the determination result in step ST104 is negative (NO), that is, if the malfunction injection state is PFI injection when a misfire occurs (when the misfire counter 110 is counted up), the process proceeds to step ST123. move on. When the PFI is abnormal, the misfire counter 110 count value of the misfire counter 110 is incremented.

  In step ST123, the operation state at the time of PFI abnormality is updated by the same process as step ST103 described above. In other words, the engine speed NE and the load factor KL at the time of misfire abnormality (when PFI is abnormal) are subjected to a smoothing process according to the above formulas (1) and (2), and the engine speed NE at the time of PFI abnormality and Update the load factor KL. In addition, the warm-up state at the time of PFI abnormality is updated to the latest state (cold or high temperature) (or if there is a cold abnormality during the detection period, the warm-up state is fixed at cold). ). After performing this update process, the process proceeds to step ST105.

  In step ST105, it is determined whether or not the count value of the detection period counter 120 has reached 1000 Rev. If the determination result is negative (NO) (in the detection period shown in FIG. 8), the process returns and returns to step ST101. Thereafter, the processing of [Step ST101 to Step ST103], [Step ST101, Step ST102, Step ST104, Step ST113] or [Step ST101, Step ST102, Step ST104, Step ST123] is positive, and the determination result of Step ST105 is positive. Each time a misfire occurs in the process of repeated processing until the determination (YES) is reached, and depending on the injection state at the time of the misfire, the above-described operation state at the time of DUAL abnormality, operation at the time of DI abnormality The state and the operation state at the time of PFI abnormality are updated.

  Then, when the count value of the detection period counter 120 reaches 1000 Rev (when the determination result of step ST105 is affirmative determination (YES)), the process proceeds to step ST106. Here, when the count value of the detection period counter 120 reaches 1000 Rev (at the end of the detection period), the updated value of the operational state at the time of DUAL abnormality (such as the final smoothing value), the updated value of the operational state at the time of DI abnormality ( The final smoothing value etc.) and the updated value (final smoothing value etc.) of the operating state at the time of PFI abnormality are stored in the RAM 103, for example.

  In step ST106, an abnormal injection state is determined. Specifically, if the count value of the misfire-time dual counter is equal to or greater than a predetermined determination value, the dual injection is determined as an abnormal injection state (dual abnormality). On the other hand, if the count value of the misfire time DUAL counter is less than the judgment value, the count value of the misfire time DI counter is compared with the count value of the misfire time PFI counter, and the injection state with the larger count value is abnormal. It is determined that the time injection state. That is, if the count value of the DI counter at the time of misfire is larger, the DI injection is determined to be an abnormal state of injection (DI abnormality), and if the count value of the PFI counter at the time of misfire is larger, the PFI injection is abnormal The injection state (PFI abnormality) is determined.

  Note that the process of determining the abnormal injection state in the above-described step ST106 is an "abnormal injection state based on a predetermined condition among a plurality of injection states when a misfire occurs within a predetermined period" in the present invention. This is equivalent to “determining”.

  Here, the determination value set for the count value of the misfire-time dual counter may be “1” or a positive integer equal to or greater than “2”. Also, determination values are set for the count value of the misfire DI counter and the count value of the misfire PFI counter. If both count values are less than the determination value, it is determined that there is no misfire abnormality. It may be.

  Next, in step ST107, it is determined whether or not the abnormality injection state determined in step ST106 is “DUAL abnormality”. If the determination result is affirmative (YES), the process proceeds to step ST108.

  In step ST108, the updated value of the operation state at the time of the DUAL abnormality when the count value of the detection period counter 120 reaches 1000 Rev (at the end of the detection period) is stored in the RAM 103, for example. Specifically, the abnormality injection state determined in step ST106 (in this case, a dual abnormality) is associated with the updated value (engine speed NE, load factor KL, warm-up state) of the operational state during the dual abnormality. Remember.

  If the determination result of step ST107 is negative (NO), the process proceeds to step ST109. In step ST109, it is determined whether or not the abnormality injection state determined in step ST106 is “DI abnormality”. If the determination result is affirmative (YES), the process proceeds to step ST118.

  In step ST118, the updated value of the operating state at the time of DI abnormality when the count value of the detection period counter 120 reaches 1000 Rev (at the end of the detection period) is stored in the RAM 103, for example. Specifically, the abnormal injection state (in this case, DI abnormality) determined in step ST106 is associated with the updated value of the DI abnormal operation state (engine speed NE, load factor KL, warm-up state). Remember.

  If the determination result in step ST107 is negative (NO), that is, if the abnormality injection state determined in step ST106 is “PFI abnormality”, the process proceeds to step ST128.

  In step ST128, the updated value of the operating state at the time of PFI abnormality when the count value of the detection period counter 120 reaches 1000 Rev (at the end of the detection period) is stored in, for example, the RAM 103. Specifically, the abnormality injection state determined in step ST106 (in this case, PFI abnormality) is associated with the updated value of the PFI abnormality operation state (engine speed NE, load factor KL, warm-up state). Remember.

  With the above processing, one misfire abnormality detection is completed. Such misfire abnormality detection processing may be repeatedly executed.

  Then, the ECU 100 performs a normal return determination based on the DUAL abnormal operation state, the DI abnormal operation state, or the PFI abnormal operation state stored in the RAM 103. One example will be described with reference to FIG.

  When the abnormal injection state and the abnormal operation state stored in the RAM 103 are a dual abnormal operation state due to a dual abnormality, as shown in FIG. 5, an updated value (an annealed value) Pdual of the dual operational state is displayed as shown in FIG. A region within a predetermined range (for example, NEdual ± 375 rpm, KLdual ± 20%) set with respect to the operation point Pdual (NEdual, KLdual) as a center point is set as a normal determination region, and engine operation in the normal determination region is performed. Perform normal return judgment in the state.

  Similarly, when the abnormal injection state and the abnormal operation state stored in the RAM 103 are DI abnormal operation states due to DI abnormality, a predetermined value set for the operation point Pdi (NEdi, KLdi) is set. A range (for example, NEdi ± 375 rpm, KLdi ± 20%) is set as a normal determination region, and normal return determination is performed in the engine operating state in the normal determination region. Similarly, when the abnormal injection state and the abnormal operation state stored in the RAM 103 are PFI abnormal operation states due to PFI abnormality, a predetermined set for the operation point Ppfi (NEpfi, KLpfi) is set. A region in a range (for example, NEpfi ± 375 rpm, Kpfi ± 20%) is set as a normal determination region, and normal return determination is performed in an engine operation state in the normal determination region.

  As described above, according to the present embodiment, the operation state and the injection state at the time of misfire are stored, and the operation state at the time of abnormality is obtained for each injection state, and is generated within the misfire abnormality detection period. An abnormal-time injection state is determined based on the number of misfires for each injection state. Since the abnormal operation state in the determined abnormal injection state is stored, the abnormal operation state is matched with the injection state (DUAL abnormality, DI abnormality, PFI abnormality) when the misfire abnormality occurs. Can be stored. Thereby, in carrying out the normal return determination after the misfire abnormality detection, the normal return determination can be appropriately performed. In addition, as shown in FIG. 5, for example, the normal determination area can be enlarged, so that opportunities for normal return determination can be increased.

  In the present embodiment, as a method of determining the abnormal injection state in step ST106, in addition to the method described above, for example, the count value of the misfire DUAL counter, the count value of the misfire DI counter, and the misfire time Of the count values of the PFI counter, a method may be employed in which the injection state having the largest count value is set to the abnormal-time injection state.

(Modification)
In the above embodiment, the injection state is divided into three states of DUAL injection, DI injection, and PFI injection. However, the present invention is not limited to this, and the injection state is expressed by the injection ratio KPFI. You may make it divide into three. One example will be described with reference to the flowchart of FIG. The control routine of FIG. 7 can also be executed by the ECU 100.

  In this example as well, the target operation states are the engine speed NE, the load factor KL, and the warm-up state. Further, the warm-up state is set to one of a cold state (a state where the water temperature is lower than the warm-up temperature (for example, 80 ° C.)) and a high temperature (a state where the water temperature is equal to or higher than the warm-up temperature).

  Also in this example, the count of the detection period counter 120 in the ECU 100 is started from the time when the control routine of FIG. 7 is started (counted in another routine), and the engine 1 (crankshaft 15) is rotated once (1 Rev). Each time the count value of the detection period counter 120 is incremented by one. ECU 100 recognizes the rotational speed of engine 1 based on the output signal of crank position sensor 201.

  In this example, the first misfire counter, the second misfire counter, and the third misfire counter are used instead of the misfire DUAL counter, misfire DI counter, and misfire PFI counter.

  When the control routine of FIG. 7 is started, first, in step ST201, it is determined whether or not the count value of the misfire counter (total misfire counter) 110 has been increased.

  If the determination result in step ST201 is negative (NO) (if the misfire counter 110 is not counted up), the process returns. When the determination result in step ST201 is affirmative (YES) (when the misfire counter 110 is counted up), the process proceeds to step ST202.

  In step ST202, it is determined whether or not the injection division rate KPFI in the abnormal injection state when the misfire occurs (when the misfire counter 110 is counted up) is [0% ≦ KPFI <30%]. If the determination result is affirmative (YES), the process proceeds to step ST203. In addition, when the ejection division ratio KPFI is in an abnormal state (0% -30% abnormal) in the range of [0% ≦ KPFI <30%], the count value of the first misfire counter of the misfire counter 110 is incremented. The

  In step ST203, the abnormal operation state (0% -30% abnormal operation state) is updated when the injection ratio KPFI is [0% ≦ KPFI <30%] by the same process as in step ST103 of FIG. To do. Specifically, the engine speed NE and the load factor KL at the time of misfire abnormality (0% -30% abnormality) are subjected to a smoothing process according to the above-described equations (1) and (2), and 0% -Update the engine speed NE and load factor KL at the time of 30% abnormality. In addition, the warm-up state at the time of abnormality of 0% -30% is updated to the latest state (cold or high temperature) (or if there is a cold abnormality during the detection period, the warm-up state is cooled). Fix in between). After performing this update process, the process proceeds to step ST205.

  If the determination result of step ST202 is negative (NO), the process proceeds to step ST204. In step ST204, it is determined whether or not the injection ratio KPFI in the abnormal injection state when a misfire occurs (when the misfire counter 110 is counted up) is [30% ≦ KPFI <70%]. If the determination result is affirmative (YES), the process proceeds to step ST213. Note that when the injection ratio KPFI is abnormal (30% -70% abnormal) in the range of [30% ≦ KPFI <70%], the count value of the second misfire counter of the misfire counter 110 is incremented. The

  In step ST213, the abnormal operation state (30% -70% abnormal operation state) is updated when the injection ratio KPFI is [30% ≦ KPFI <70%] by the same process as in step ST103 of FIG. To do. Specifically, the engine speed NE and the load factor KL at the time of misfire abnormality (30% -70% abnormality) are subjected to a smoothing process according to the above formulas (1) and (2), and 30% -Update the engine speed NE and load factor KL at the time of 70% abnormality. Also, the warm-up state at the time of 30% -70% abnormality is updated to the latest state (cold or high temperature) (or if there is a cold abnormality during the detection period, the warm-up state is Fix in between). After performing this update process, the process proceeds to step ST205.

  When the determination result of step ST204 is negative (NO), that is, when the misfire occurs (when the misfire counter 110 is counted up), the injection ratio KPFI in the abnormal injection state is [70% ≦ If KPFI ≦ 100%], the process proceeds to step ST223. In addition, when the injection ratio KPFI is in an abnormal state within the range of [70% ≦ KPFI ≦ 100%] (70% -100% abnormal), the count value of the third misfire counter of the misfire counter 110 is incremented. The

  In step ST223, the abnormal operation state (70% -100% abnormal operation state) is updated when the injection ratio KPFI is [70% ≦ KPFI ≦ 100%] by the same processing as in step ST103 of FIG. 4 described above. To do. Specifically, the engine speed NE and the load factor KL when the misfire is abnormal (70% -100% abnormal) are subjected to a smoothing process according to the above formulas (1) and (2), and 70% -Update the engine speed NE and the load factor KL at the time of 100% abnormality. In addition, the warm-up state at the time of 70% -100% abnormality is updated to the latest state (cold or high temperature) (or if there is a cold abnormality during the detection period, the warm-up state is cooled). Fix in between). After performing this update process, the process proceeds to step ST205.

  In step ST205, it is determined whether or not the count value of the detection period counter 120 has reached 1000 Rev. If the determination result is negative (NO) (within the detection period shown in FIG. 8), the process returns and returns to step ST201. Thereafter, the processing of [Step ST201 to Step ST203], [Step ST201, Step ST202, Step ST204, Step ST213], or [Step ST201, Step ST202, Step ST204, Step ST223] is affirmed. Each time a misfire occurs in the process of the repetition process, the above-described 0% -30% abnormal operation state, depending on the injection state at the time of the misfire, The 30% -70% abnormal operation state and the 70% -100% abnormal operation state are updated respectively.

  Then, the process proceeds to step ST206 when the count value of the detection period counter 120 reaches 1000 Rev (when the determination result of step ST205 is affirmative determination (YES)). Here, when the count value of the detection period counter 120 reaches 1000 Rev (at the end of the detection period), the updated value of the operating state at the time of abnormality of 0% -30% (final smoothing value, etc.), 30% -70% An updated value (such as the final smoothing value) of the abnormal operating state and an updated value (such as the final smoothed value) of the abnormal operating state of 70% -100% are stored in, for example, the RAM 103 (see FIG. 1).

  In step ST206, an abnormal injection state is determined. Specifically, the count value of the first misfire counter (for 0% -30% misfire), the count value of the second misfire counter (for 30% -70% abnormal time), and the third The count value of the misfire counter (for 70% -100% abnormal time) is compared, and the injection state with the maximum count value is determined as the abnormal injection state. That is, when the count value of the first misfire counter is the maximum, the abnormality injection state is determined as “0% -30% abnormality”. Further, when the count value of the second misfire counter is maximum, the abnormal injection state is determined as “30% -70% abnormal”, and when the third misfire counter value is the largest, the abnormal injection state is determined. Is determined as “70% -100% abnormal”.

  Next, in step ST207, it is determined whether or not the abnormality injection state determined in step ST206 is “0% -30% abnormality”. If the determination result is affirmative (YES), step ST208. Proceed to

  In step ST208, the updated value of the 0% -30% abnormal operation state when the count value of the detection period counter 120 reaches 1000 Rev (at the end of the detection period) is stored in the RAM 103, for example. Specifically, the abnormal injection state determined in step ST206 (in this case, 0% -30% abnormality) and the updated value of the 0% -30% abnormal operation state (engine speed NE, load factor KL, The warm-up state) is stored in association with each other.

  When the determination result of step ST207 is negative (NO), the process proceeds to step ST209. In step ST209, it is determined whether or not the abnormal injection state determined in step ST206 is “30% -70% abnormal”. If the determination result is affirmative (YES), the process proceeds to step ST218.

  In step ST218, the updated value of the 30% -70% abnormal operation state when the count value of the detection period counter 120 reaches 1000 Rev (at the end of the detection period) is stored in the RAM 103, for example. Specifically, the abnormal injection state determined in step ST206 (in this case, 30% -70% abnormality) and the 30% -70% abnormal operation state (engine speed NE, load factor KL, warm-up state) ) And the updated value are stored in association with each other.

  If the determination result in step ST207 is negative (NO), that is, if the abnormal injection state determined in step ST206 is “70% -100% abnormal”, the process proceeds to step ST228.

  In step ST228, the updated value of the 70% -100% abnormal operation state when the count value of the detection period counter 120 reaches 1000 Rev (at the end of the detection period) is stored in, for example, the RAM 103. Specifically, the abnormal injection state determined in step ST206 (70% -100% abnormality in this case) and the 70% -100% abnormal operation state (engine speed NE, load factor KL, warm-up state) ) And the updated value are stored in association with each other.

  With the above processing, one misfire abnormality detection is completed. Such misfire abnormality detection processing may be repeatedly executed.

  Then, the ECU 100 performs a normal return determination based on the DUAL abnormal operation state, the DI abnormal operation state, or the PFI abnormal operation state stored in the RAM 103. Since the process for the normal return determination is basically the same as the process of the above-described embodiment (the process described with reference to FIG. 5), the specific description thereof is omitted.

  Also in this modified example, when an abnormality occurs according to the injection state when the misfire abnormality occurs, that is, the division of the injection ratio KPFI (0% -30% abnormality, 30% -70% abnormality, 70% -100% abnormality) The operating state (engine speed NE, load factor KL, warm-up state) can be stored. Thereby, in carrying out the normal return determination, the normal return determination can be appropriately performed.

  In this modification, the injection state is divided into three by the injection division rate KPFI, but is not limited thereto, and the injection state is divided into two or four or more by the injection division rate KPFI, A misfire abnormality may be detected.

-Other embodiments-
In the above example, the engine speed NE and the load factor KL when a misfire occurs are subjected to a ½ smoothing process to obtain an abnormal operation update value (smoothed value). For example, the smoothing value of the engine speed NE and the smoothing value of the load factor may be calculated by a smoothing process of any other smoothing coefficient such as a 1/4 smoothing process.

  In the above example, the smoothed value obtained by performing the smoothing process on the engine speed NE and the load factor KL at the time of misfire is used as the updated value of the abnormal operation state, but the present invention is not limited to this. Not.

  For example, in the misfire abnormality detection period shown in FIG. 8, the average value of the engine speed NE and the average value of the load factor KL for each injection state when a misfire occurs are calculated as the abnormal operation state for each injection state. It may be an updated value. In addition, when the misfire occurs within the detection period shown in FIG. 8, the engine speed NE and the load factor KL for each injection state are sequentially updated and stored to the latest values, and the detection period ends. In addition, the last updated value within the detection period may be used as the updated value of the abnormal operation state for each injection state.

  In the above example, it is determined that the detection period ends when the count value of the detection period counter 120 reaches 1000 Rev (the number of engine revolutions = 1000 revolutions). However, the present invention is not limited to this. When the count value reaches 200 Rev (number of engine revolutions = 200 revolutions), the detection period may be determined to end. Further, the end of the detection period may be determined when the count value reaches an arbitrary numerical value (Rev) other than 1000 Rev and 200 Rev. Note that the misfire abnormality detection period may be determined based on the elapsed time from the start of detection or the travel distance.

  In the above example, an area within a predetermined range set in advance with respect to the updated value of the abnormal operation state is set as a normal determination area, and normal return determination is performed in the engine operation state in the normal determination area. The present invention is not limited to this, and the normal return determination may be performed in the same engine operating state as the updated value of the abnormal operating state.

  In the above example, the case where the present invention is applied to a four-cylinder gasoline engine has been described. However, the present invention is not limited to this, and can be applied to a gasoline engine having any number of cylinders such as a six-cylinder gasoline engine. It is. In addition to the in-line multi-cylinder gasoline engine, the present invention can be applied to control of a V-type multi-cylinder gasoline engine.

  The present invention includes an in-cylinder fuel injection valve that directly injects fuel into a combustion chamber, and an intake passage fuel injection valve that injects fuel into an intake passage, and one of a plurality of injection states having different injection ratios. The present invention can be effectively used in a misfire abnormality detection device for an internal combustion engine that can be selectively switched to one injection state.

1 Engine 1d Actual combustion 11 Intake passage 11a Intake port 2a In-cylinder injector (in-cylinder fuel injection valve)
2b Injector for port injection (fuel injection valve for intake passage)
100 ECU
103 RAM
110 Misfire counter 120 Detection period counter

Claims (5)

An in-cylinder fuel injection valve that directly injects fuel into the combustion chamber and an intake passage fuel injection valve that injects fuel into the intake passage, and is in one of a plurality of injection states with different injection ratios. A misfire abnormality detection device for an internal combustion engine that can be selectively switched,
The operation state and the injection state of the internal combustion engine when misfiring has occurred are stored, the abnormal operation state is obtained for each of the plurality of injection states, and the plurality of injections when misfire has occurred within a predetermined period An abnormality injection state is determined based on a predetermined condition from among the states, and the determined abnormality injection state and the abnormal operation state in the abnormality injection state are stored in association with each other. Engine misfire abnormality detection device. The misfire abnormality detection device for an internal combustion engine according to claim 1,
An abnormality detection apparatus for misfiring of an internal combustion engine, wherein an abnormality injection state is determined based on the number of misfires for each injection state occurring within the predetermined period. The misfire abnormality detection device for an internal combustion engine according to claim 1 or 2,
A misfire abnormality detection device for an internal combustion engine, which performs a normal return determination when the injection state is the same as the determined abnormal injection state and is in an operation state similar to the stored abnormal operation state . The misfire abnormality detection device for an internal combustion engine according to claim 3,
The similar operation state is the same engine operation state as the stored abnormal operation state, or an engine operation state within a predetermined range preset with respect to the abnormal operation state. A misfire abnormality detection device for an internal combustion engine. The misfire abnormality detection device for an internal combustion engine according to any one of claims 1 to 4,
The engine operating state is an engine speed, an engine load factor, a warm-up state,
The injection state includes an injection state in which fuel is injected only by an in-cylinder fuel injection valve, an injection state in which fuel is injected only by an intake passage fuel injection valve, an in-cylinder fuel injection valve, and an intake passage fuel injection valve. A misfire abnormality detection device for an internal combustion engine, characterized by being in an injection state in which fuel is injected.

Images