Ignition control system for internal combustion engine

Abstract

To provide an ignition control system for an internal combustion engine which can appropriately shorten a conduction time to an ignition coil which supplies electric energy to an ignition plug to suppress shortening of life of the ignition plug by temporarily shortening the conduction time to the ignition coil and determining whether there is an accidental fire or not and further decreasing a margin for individual differences and variations of the ignition coil and the ignition plug.SOLUTION: A control device controls an ignition coil for a post-correction conduction time which is determined by subtracting a correction time from a base conduction time. When an update condition for the correction time is satisfied, conduction shortening control is executed where the correction time is temporarily prolonged and the post-correction conduction time is shortened until at least one cylinder is misfired. After that, conduction extension control is executed where the correction time is temporarily shortened and the post-correction conduction time is prolonged until all the cylinders are not misfired. If all the cylinders do not misfire, the conduction extension control is ended and the correction time at the time of ending is updated to a new correction time.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to an ignition control system for a spark ignition internal combustion engine. [Background technology]

[0002] Traditionally, spark-ignition internal combustion engines have used a spark from a spark plug in the combustion chamber to ignite the air-fuel mixture and initiate the combustion process. However, as the electrodes of a spark plug gradually wear over time, the electrical energy required to generate a spark gradually increases. Taking this deterioration into account, sufficient electrical energy is provided to prevent misfires. However, the more electrical energy is provided to the spark plug, the more the electrodes of the spark plug wear, shortening the lifespan of the spark plug. The spark plug receives electrical energy from an ignition coil, which stores electrical energy according to the duration of current flow controlled by a control device and supplies the stored electrical energy to the spark plug.

[0003] For example, Patent Document 1 discloses an engine ignition control device that energizes an ignition coil for a period of time based on a base energization time calculated based on engine speed, causing the spark plug to discharge (generate a spark). Patent Document 1 also discloses an engine ignition control device that accumulates either the number of times the spark plug ignites or the engine operating time, and corrects the base energization time so that the greater the accumulated number of ignitions or the engine operating time, the longer the energization time. Patent Document 1 discloses an engine ignition control device that prevents electrical energy shortages in response to deterioration of the spark plug electrodes over time, and does not supply more electrical energy than necessary before deterioration over time progresses, thereby preventing the spark plug from shortening its lifespan. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-241649 Summary of the Invention [Problem to be solved by the invention]

[0005] Ignition coils and spark plugs vary from one another, and as a result of deterioration over time, the electrical energy required also varies from one another. In the cited document 1, a margin is required to take these individual differences and variations into account in order to prevent misfires, and a longer current application time must be set to accommodate this margin. Therefore, in the cited document 1, depending on the individual differences and variations in the ignition coils and spark plugs, more electrical energy than necessary may be supplied.

[0006] The present invention was devised in consideration of these points, and its objective is to provide an ignition control system for an internal combustion engine that can temporarily shorten the time that electricity is supplied to the ignition coil that supplies electrical energy to the spark plug and determine whether or not a misfire has occurred, thereby reducing the margin for individual differences and variations in the ignition coil and spark plug, and more appropriately shortening the time that electricity is supplied to the ignition coil, thereby further preventing the shortening of the lifespan of the spark plug. [Means for solving the problem]

[0007] To solve the above problems, a first invention is an ignition control system for an internal combustion engine having a spark plug provided for each cylinder, an ignition coil provided for each spark plug to supply electrical energy to the spark plug, and a control device that controls each of the ignition coils, wherein the control device controls each of the ignition coils based on a corrected current conduction time obtained by subtracting a correction time from a base current conduction time set based on an operating state of the internal combustion engine, and when an update condition for the correction time is satisfied, controls each of the ignition coils based on the corrected current conduction time, in which a predetermined correction time is temporarily set as the correction time and is shorter than the base current conduction time, to determine whether or not a misfire has occurred in each cylinder, and performs correction time update control to update the predetermined correction time to a new correction time if no misfire has occurred in any of the cylinders.

[0008] A second aspect of the present invention is an ignition control system for an internal combustion engine having a spark plug provided for each cylinder, an ignition coil provided for each spark plug to supply electrical energy to the spark plug, and a control device that controls each of the ignition coils, wherein the control device controls each of the ignition coils based on a corrected current supply time obtained by subtracting a correction time from a base current supply time set based on an operating state of the internal combustion engine, and if an update condition for the correction time is satisfied, performs current supply reduction control to temporarily shorten the corrected current supply time by temporarily extending the correction time until at least one cylinder misfires, terminates the current supply reduction control if at least one cylinder misfires during the current supply reduction control and performs current supply extension control to temporarily extend the corrected current supply time by temporarily shortening the correction time until all cylinders no longer misfire, and if all cylinders do not misfire during the current supply extension control after the current supply reduction control, performs correction time update control to terminate the current supply extension control and update the correction time at the time of termination to a new correction time.

[0009] Next, a third invention is an ignition control system for an internal combustion engine according to the second invention, wherein when the control device temporarily shortens the corrected current supply time using the current supply reduction control, it adds a first correction time to the correction time to determine whether or not misfire has occurred in each cylinder, and if none of the cylinders has misfired, it repeats the process of adding the first correction time to the correction time again to determine whether or not misfire has occurred in each cylinder.

[0010] Next, a fourth invention is an ignition control system for an internal combustion engine according to the second invention, wherein when the control device temporarily extends the corrected current supply time using the current supply extension control, it subtracts a second correction time from the correction time to determine whether or not misfire has occurred in each cylinder, and if at least one cylinder has misfired, it repeats the process of subtracting the second correction time from the correction time again to determine whether or not misfire has occurred in each cylinder.

[0011] Next, a fifth invention is an ignition control system for an internal combustion engine according to any one of the first to fourth inventions, wherein the correction time is set for each of a plurality of operating regions according to the operating state of the internal combustion engine, and the control device calculates the corrected current application time using the correction time for the operating region according to the operating state, and when the update condition for the correction time is satisfied, executes the correction time update control for the correction time for the operating region according to the operating state, thereby updating the correction time for which no cylinder misfired to a new correction time for the operating region.

[0012] Next, a sixth invention is an ignition control system for an internal combustion engine according to any one of the second to fourth inventions, wherein the control device controls each of the ignition coils based on the corrected current flow time obtained by subtracting the correction time from the base current flow time when the update condition for the correction time is not satisfied, and determines whether or not there is misfire in each cylinder when a misfire detection condition is satisfied, and updates the correction time obtained by subtracting a third correction time from the correction time to a new correction time when misfire is detected in at least one cylinder. [Effects of the Invention]

[0013] According to the first aspect of the present invention, when a condition for updating the correction time is satisfied, the control device controls the ignition coil based on a corrected energization time obtained by subtracting a predetermined correction time corresponding to, for example, the cumulative operating time of the engine as the correction time and shortening the base energization time by the correction time. If none of the cylinders misfire, the control device updates the predetermined correction time as a new correction time. If at least one cylinder misfires, the control device does not update the correction time. This temporarily shortens the energization time of the ignition coil to determine whether or not a misfire has occurred, thereby reducing the margin for individual differences and variations in the ignition coil and spark plug, making it possible to more appropriately shorten the energization time of the ignition coil and further suppressing a shortened lifespan of the spark plug.

[0014] According to the second aspect of the present invention, when the update condition for the correction time is satisfied, the control device lengthens the correction time until at least one cylinder misfires (shortens the post-correction current supply time), and then shortens the correction time until all cylinders no longer misfire (lengthens the post-correction current supply time). This temporarily shortens the current supply time to the ignition coil to determine whether or not a misfire has occurred, thereby reducing the margin for individual differences and variations in the ignition coil and spark plug, making it possible to more appropriately shorten the current supply time to the ignition coil and further suppress a shortened lifespan of the spark plug.

[0015] According to the third aspect of the present invention, when the update condition for the correction time is satisfied, the corrected current supply time is temporarily shortened by the first correction time to determine whether or not a misfire has occurred, thereby preventing the corrected current supply time from being temporarily shortened more than necessary (causing more misfires than necessary).

[0016] According to the fourth aspect of the present invention, when the update condition for the correction time is satisfied, the corrected current supply time is temporarily extended by the second correction time to determine whether or not a misfire has occurred, thereby preventing the corrected current supply time from being temporarily extended more than necessary.

[0017] According to the fifth aspect of the present invention, by setting the correction time for each operating region based on the operating state of the internal combustion engine, the corrected current application time can be shortened to a length more appropriate for the operating state.

[0018] As the deterioration of the spark plug electrodes progresses gradually, the required electrical energy gradually increases. If the correction time update conditions are not satisfied, a corrected current flow time that is shorter than the base current flow time may cause the deterioration of the spark plug electrodes to progress more than expected, potentially resulting in a misfire. According to the sixth aspect of the present invention, if a misfire occurs when the correction time update conditions are not satisfied, the correction time can be shortened and the corrected current flow time can be lengthened, thereby preventing the misfire from continuing. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a diagram illustrating an example of the overall configuration of an internal combustion engine system. [Figure 2] FIG. 2 is a diagram illustrating an example of an input / output circuit between a control device and an igniter (ignition coil). [Figure 3] 4 is a flowchart illustrating an example of an "overall process" of a processing procedure of the control device in the first embodiment of the present invention. [Figure 4] 10 is a flowchart illustrating an example of a "correction time update process" of the processing procedure of the control device in the first embodiment. [Figure 5] 10 is a flowchart illustrating an example of a "processing of post-update elapsed time" in the processing procedure of the control device in the first embodiment. [Figure 6] 4 is a flowchart illustrating an example of a power supply start setting process of the processing procedure of the control device in the first embodiment. [Figure 7] 10 is a flowchart illustrating an example of a "power distribution end setting process" of the processing procedure of the control device in the first embodiment. [Figure 8] FIG. 10 is a diagram illustrating an example in which a non-volatile correction time (m, n), a post-update elapsed time (m, n), and an update completion flag (m, n) are set for each operating region (m, n) according to the operating state of the internal combustion engine. [Figure 9] FIG. 10 is a diagram illustrating an example of a base current-carrying time characteristic. [Figure 10] FIG. 3 is a diagram illustrating an example (example 1) of an operational waveform in the first embodiment. [Figure 11] FIG. 4 is a diagram illustrating an example (Example 2) of an operational waveform in the first embodiment. [Figure 12] 10 is a flowchart illustrating an example of a "correction time update process" of the processing procedure of the control device in the second embodiment. [Figure 13] 10 is a flowchart illustrating an example of "processing of accumulated operating time" in the processing procedure of the control device in the second embodiment. [Figure 14] FIG. 10 is a diagram illustrating an example of the [accumulated operating time vs. fourth corrected time characteristic] in the second embodiment. [Figure 15]FIG. 10 is a diagram illustrating an example (Example 3) of an operational waveform in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0020] <Overall configuration of internal combustion engine system 1 (Fig. 1)> An internal combustion engine system 1 including an ignition control system 2 of the present invention will be described below with reference to the drawings. First, an example of the overall configuration of the internal combustion engine system 1 will be described using FIG. 1. Note that the internal combustion engine 10 of the internal combustion engine system 1 in the example of FIG. 1 is a so-called gasoline engine. In the following description, an example will be described in which the internal combustion engine 10 has four cylinders. The ignition control system 2 has a control device 50, an ignition plug 71, and an igniter 72. The configuration of the internal combustion engine system 1 will be described below, starting from the intake side to the exhaust side.

[0021] An air flow rate detecting device 31 is provided in the intake pipe 11A. The air flow rate detecting device 31 (e.g., an intake air flow rate sensor) outputs a detection signal corresponding to the flow rate [g / sec] of air taken in by the internal combustion engine 10 to the control device 50. The air flow rate detecting device 31 is also provided with an intake air temperature detecting device 32A and an atmospheric pressure detecting device 33A. The intake air temperature detecting device 32A (e.g., an intake air temperature sensor) outputs a detection signal corresponding to the temperature of the intake air (in this case, the temperature of outside air) to the control device 50. The atmospheric pressure detecting device 33A (e.g., a pressure sensor) outputs a detection signal corresponding to the atmospheric pressure to the control device 50. The downstream side of the intake pipe 11A is connected to the upstream side of a throttle device 64.

[0022] The throttle device 64 has a motor 64A that adjusts the opening of the throttle valve to a target throttle opening based on a control signal from the control device 50, and an opening detection device 64B (e.g., an opening sensor) that outputs a detection signal corresponding to the opening of the throttle valve to the control device 50. The upstream side of the intake pipe 11C is connected to the downstream side of the throttle device 64, and the downstream side of the intake pipe 11C is connected to the upstream side of the intake manifold 11D. The downstream side of the EGR pipe 13 is also connected to the intake pipe 11C.

[0023] The downstream side of the intake manifold 11D is connected to an intake port that guides intake air to each cylinder of the internal combustion engine 10, and the intake port is provided with an injector 21. The intake air guided to the intake manifold 11D is drawn into each cylinder of the internal combustion engine 10 and used for combustion together with fuel injected from the injector 21.

[0024] The internal combustion engine 10 is also provided with a spark plug 71, which generates a spark in the combustion chamber using electrical energy supplied from an ignition coil of an igniter 72, igniting the air-fuel mixture in the combustion chamber. The control device 50 outputs a control signal to the ignition coil of the igniter 72, causing the ignition coil to store electrical energy and release the stored electrical energy to the spark plug 71. An injector 21 and a spark plug 71 are provided for each cylinder, and an igniter 72 (ignition coil) is provided for each spark plug 71. The primary coil 72C and secondary coil 72D shown in FIG. 2 correspond to the ignition coil.

[0025] The internal combustion engine 10 is provided with a rotation detection device 34A and a cylinder detection device 34B. The rotation detection device 34A (for example, a crankshaft rotation sensor) outputs a detection signal (crank angle signal) corresponding to the rotation angle of the crankshaft of the internal combustion engine 10 to the control device 50. Furthermore, the cylinder detection device 34B (for example, a camshaft rotation sensor) outputs a detection signal (cylinder discrimination signal) to the control device 50 when, for example, the piston of the first cylinder reaches top dead center of compression.

[0026] The internal combustion engine 10 is also provided with a coolant temperature detection device 32C. The coolant temperature detection device 32C (for example, a water temperature sensor) outputs to the control device 50 a detection signal corresponding to the temperature of the coolant (cooling water) that cools the internal combustion engine.

[0027] An accelerator depression amount detection device 38 (for example, an accelerator depression amount sensor) outputs a detection signal corresponding to the depression amount of the accelerator pedal operated by the driver to the control device 50. An ignition switch 39 is an input device for the driver to input commands to start or stop the internal combustion engine.

[0028] An exhaust manifold 12A is connected to an exhaust port of the internal combustion engine 10. Exhaust from the internal combustion engine 10 passes through the exhaust manifold 12A and an exhaust purification device 40 (such as a three-way catalyst) and is discharged into an exhaust pipe 12C.

[0029] The inlet side of EGR pipe 13, which returns part of the exhaust gas to the intake air, is connected to exhaust manifold 12A or exhaust pipe 12B. The outlet side of EGR pipe 13 is connected to intake pipe 11C (or intake manifold 11D). EGR pipe 13 is provided with EGR valve 13A, which is controlled by control device 50 to adjust the opening of the EGR pipe.

[0030] An exhaust pipe 12B is connected to the downstream side of exhaust manifold 12A. The upstream side of exhaust purification device 40 is connected to the downstream side of exhaust pipe 12B, and exhaust pipe 12C is connected to the downstream side of exhaust purification device 40. An A / F detection device 48 is also provided in exhaust manifold 12A. A / F detection device 48 (e.g., an A / F sensor) outputs a detection signal to control device 50 according to the air-fuel ratio of the exhaust gas.

[0031] For example, the control device 50 calculates the required fuel amount so that the air-fuel ratio detected by the A / F detection device 48 becomes the stoichiometric air-fuel ratio, based on the rotation speed of the internal combustion engine based on the detection signal from the rotation detection device 34A and the air flow rate based on the detection signal from the air flow rate detection device 31. Then, based on the detection signals from the rotation detection device 34A and the cylinder detection device 34B, the control device 50 controls the injector 21 at a predetermined timing to inject the required fuel amount into each of the #1 to #4 cylinders (in the case of a four-cylinder engine) of the internal combustion engine 10, and outputs a control signal to the ignition coil of the igniter 72 of each cylinder.

[0032] The exhaust purification device 40 (for example, a three-way catalyst) purifies carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NOx), and the like contained in the exhaust gas.

[0033] 2, the control device 50 is a known device including a CPU 51, a RAM 52, a ROM 53 (storage device), a timer 54, and a nonvolatile storage device 55 (e.g., an EEPROM). The CPU 51 executes various calculation processes based on various programs and maps stored in the ROM 53 (e.g., a Flash-ROM). The RAM 52 temporarily stores the results of calculations performed by the CPU and data input from each detection device, and the nonvolatile storage device 55 stores data that should be saved when the internal combustion engine 10 is stopped, for example.

[0034] Based on the input detection signals, the control device 50 can detect various operating states of the internal combustion engine 10. Furthermore, in response to the detected operating state of the internal combustion engine 10 and a request from the driver based on a detection signal from the accelerator depression amount detection device 38, the control device 50 outputs control signals to control various actuators such as the injector 21 that injects fuel into the cylinder, the igniter 72 (ignition coil), the throttle device 64, and the EGR valve 13A.

[0035] 2 shows an example of the input / output section between the control device 50 and the igniter 72. The control device 50 has a constant-voltage power supply 56A and an ignition control input / output circuit 57, and the igniter 72 has a primary coil 72C, a secondary coil 72D, a drive circuit 72A, an ignition confirmation signal generating circuit 72B, etc. A spark plug 71 is provided for each cylinder, and an igniter 72 (ignition coil) and an ignition control input / output circuit 57 are provided for each spark plug. The primary coil 72C and secondary coil 72D correspond to the ignition coils.

[0036] When the control device 50 outputs a pulse P1 (control signal) from the timer 54 of the CPU 51 to the igniter 72 (ignition coil), which rises at time TX and falls at time TY, the ignition coil of the igniter 72 stores electrical energy from time TX and releases the stored electrical energy to the spark plug 71 at time TY, generating a spark between the electrodes of the spark plug 71. The electrical energy increases as the pulse width W (corresponding to the current application time) of the pulse P1 becomes longer. When a spark occurs in the spark plug 71, a pulse P2 is generated in the ignition confirmation signal generating circuit 72B, and the control device 50 can confirm that ignition has occurred (that a spark has occurred) by receiving the pulse P2 in response to the pulse P1.

[0037] To generate a spark between the electrodes of the spark plug 71, the electrical energy required to generate the spark must be supplied from the ignition coil of the igniter 72 to the spark plug 71. If the supplied electrical energy is insufficient compared to the required electrical energy, a spark will not be generated, resulting in a misfire in the internal combustion engine 10. Furthermore, the electrodes of the spark plug 71 wear and deteriorate each time a spark is generated, gradually increasing the required electrical energy. Taking into account this deterioration, individual differences, and variations, the pulse width W of the pulse P1 (control signal) from the control device 50 is set to a somewhat long pulse width so that electrical energy greater than the required electrical energy can be supplied even if the expected deterioration (including individual differences and variations) progresses.

[0038] Because a somewhat long pulse width W is set in consideration of deterioration, individual differences, and variations, there are cases in which electrical energy that is higher than necessary for the required electrical energy is supplied. In this case, the deterioration of the spark plug 71 progresses more than necessary, which is undesirable because it shortens the life of the spark plug 71. Therefore, by performing the processing described in the following first and second embodiments, misfires can be detected even in the presence of deterioration, individual differences, and variations, and the pulse width W (corresponding to the energization time) of the pulse P1 (control signal) can be set to a shorter pulse width, thereby further suppressing a shortened life of the spark plug 71.

[0039] <Processing Procedures of the Control Device 50 in the First Embodiment (FIGS. 3 to 11)> <Overall processing (Fig. 3)> Next, the processing of the control device 50 (CPU 51) in the first embodiment will be described with reference to Figures 3 to 11. The control device 50 (CPU 51) starts the "overall processing" shown in Figure 3 at the timing of the compression top dead center of each cylinder, for example, and proceeds to step S10.

[0040] In step S10, the control device 50 acquires various operating states of the internal combustion engine (internal combustion engine system 1). The acquired operating states include physical quantities (such as engine speed) based on detection signals from the various detection devices described above, such as the engine speed, intake air volume, fuel injection amount, accelerator pedal depression amount, and outside air temperature, physical quantities (such as fuel injection amount) based on control amounts of actuators controlled by the control device 50 itself, and physical quantities (such as exhaust flow velocity) calculated using these physical quantities. The control device 50 then determines the operating region (m, n) based on the acquired operating states.

[0041] As shown in FIG. 8, a plurality of operating regions (m, n) according to the operating state are set according to the engine speed and the load on the engine (fuel injection amount, accelerator pedal depression amount, etc.). The example in FIG. 8 shows an example in which nine operating regions (m, n) are set, from operating region (1, 1) to operating region (3, 3). Each operating region (m, n) has a non-volatile correction time (m, n), a time elapsed since update (m, n), and an update completion flag (m, n). The non-volatile correction time (m, n), the time elapsed since update (m, n), and the update completion flag (m, n) are stored in a non-volatile storage device.

[0042] The control device 50 determines the operating region (m, n) for the current process according to the engine speed and load. The control device 50 then calculates the current crankshaft angular velocity ω [rad / sec] from the time required for 180-degree crank angle rotation (in the case of a four-cylinder engine) based on the time of the previous compression top dead center and the time of the current compression top dead center, stores the angular velocity ω, and proceeds to step S15. The angular velocity ω is used to determine whether or not a misfire has occurred.

[0043] In step S15, the control device 50 determines whether or not the warm-up of the internal combustion engine has been completed (for example, whether or not the coolant temperature is equal to or higher than a predetermined temperature). If the control device 50 determines that the warm-up of the internal combustion engine has been completed (Yes), the control device 50 proceeds to step S20, and if the control device 50 determines that the warm-up has not been completed (No), the control device 50 proceeds to step S70.

[0044] When the process proceeds to step S20, the control device 50 determines whether the update completion flag (m, n) corresponding to the current operating region (m, n) is OFF (update not yet performed). The update completion flag (m, n) is initially OFF, and is a flag that is set to ON when the non-volatile correction time (m, n) for the corresponding operating region (m, n) has been updated at least once. If the update completion flag (m, n) is OFF (Yes), the control device 50 proceeds to step S30, and if the update completion flag (m, n) is not OFF (No), the control device 50 proceeds to step S25.

[0045] If the process proceeds to step S25, the control device 50 determines whether the post-update elapsed time (m, n) corresponding to the current driving region (m, n) is equal to or greater than a predetermined time. The post-update elapsed time (m, n) is initially set to zero and indicates the elapsed time since the non-volatile correction time (m, n) for the corresponding driving region (m, n) was updated. The predetermined time is set to an appropriate value determined by experiments using an actual vehicle, a simulator, or the like. If the post-update elapsed time (m, n) is equal to or greater than the predetermined time (Yes), the control device 50 proceeds to step S30. If the post-update elapsed time (m, n) is less than the predetermined time (No), the control device 50 proceeds to step S60. Note that if the process proceeds to step S30 in steps S15, S20, and S25, the correction time update condition is met, and if the process proceeds to step S60, the correction time update condition is not met.

[0046] When the process proceeds to step S30, the control device 50 determines whether the update processing in progress flag is OFF. The update processing in progress flag is a flag that is set ON in step S35 of Fig. 3, and is set OFF in step U80 of Fig. 4 and step S80 of Fig. 3, and is set ON while the "correction time update process" of step S45 of Fig. 3 is being executed. If the update processing in progress flag is OFF (Yes), the control device 50 proceeds to step S35, and if the update processing in progress flag is not OFF (No), the control device 50 proceeds to step S40.

[0047] When the process proceeds to step S35 (when the correction time update process is started), the control device 50 performs the following settings to start the correction time update process. The control device 50 sets the update process in progress flag to ON, copies the current operating region (m, n) to the start operating region, sets the operation mode to "1," sets the correction increase / decrease flag to ON, reads out the non-volatile correction time (m, n) corresponding to the current operating region (m, n) and copies it to the correction time, and then proceeds to step S40. Note that the non-volatile correction time (m, n) is a learned value stored in the non-volatile storage device and corresponds to the correction time. However, since the correction time may temporarily increase or decrease, erroneous learning must be avoided. Therefore, the non-volatile correction time (m, n) is copied to the correction time, the copied correction time is increased or decreased, and when the final correction time is determined, the correction time is copied to the non-volatile correction time (m, n).

[0048] When the process proceeds to step S40, the control device 50 determines whether the current operating range (m, n) matches the start operating range. If the current operating range (m, n) matches the start operating range (Yes), the control device 50 proceeds to step S45. If the current operating range (m, n) does not match the start operating range (No), the control device 50 stops the update process because the operating range has changed even though the correction time is being updated, and proceeds to step S75.

[0049] If the process proceeds to step S45, the control device 50 executes "correction time update process" and proceeds to step S90. The "correction time update process" will be described in detail later.

[0050] If the process proceeds to step S90, the control device 50 acquires a base current conduction time, which is the base of the current conduction time of the control signal to the ignition coil of the igniter, and copies the current conduction time obtained by subtracting the correction time from the base current conduction time to the corrected current conduction time, and then proceeds to step S95. FIG. 9 shows an example of the base current conduction time characteristic. The base current conduction time is set as a current conduction time (Wmn) corresponding to the rotation speed (Nn) of the internal combustion engine and the load of the internal combustion engine (Lm: fuel injection amount, accelerator pedal depression amount, etc.). The current conduction time (Wmn) is set to an appropriate value selected through experiments and simulations using an actual vehicle.

[0051] In step S95, the control device 50 copies the angular velocity ω3 (angular velocity ω during the third processing cycle prior) to the angular velocity ω4 (angular velocity ω during the fourth processing cycle prior) and copies the angular velocity ω2 (angular velocity ω during the second processing cycle prior) to the angular velocity ω3 for use in determining misfire during the next processing cycle. Furthermore, the control device 50 copies the angular velocity ω1 (angular velocity ω during the one processing cycle prior) to the angular velocity ω2 and copies the current angular velocity ω to the angular velocity ω1, and then ends the processing shown in FIG. 3.

[0052] If the process proceeds to step S60, the control device 50 determines whether the misfire detection conditions are met. The processes of steps S60 to S80 are normal processes that do not update the correction time. However, if a misfire occurs when the corrected current supply time is set shorter than the base current supply time, the corrected current supply time is lengthened to prevent the misfire from continuing. The misfire detection conditions are, for example, that warm-up is complete, that the amount of fluctuation in the internal combustion engine speed is within a predetermined range, that the amount of fluctuation in the internal combustion engine load is within a predetermined range, and that the operating range (m, n) during the previous process matches the operating range (m, n) during the current process. If the misfire detection conditions are met (Yes), the control device 50 proceeds to step S65. If the misfire detection conditions are not met (No), the control device 50 proceeds to step S75.

[0053] If the process proceeds to step S65, the control device 50 determines whether a misfire has occurred. For example, the control device 50 determines that a misfire has occurred if the difference between the current angular velocity ω of the crankshaft and the angular velocity ω at the previous processing time (or the angular velocity ω4 at the processing time four times before (in the case of a four-cylinder engine)) is equal to or greater than a predetermined amount. Note that the method for determining whether a misfire has occurred is not limited to determination based on the angular velocity ω, and any determination method may be used. If the control device 50 determines that a misfire has occurred (Yes), the process proceeds to step S70, and if it determines that a misfire has not occurred (No), the process proceeds to step S75.

[0054] If the process proceeds to step S70, the control device 50 reads the non-volatile correction time (m, n) corresponding to the current operating region (m, n), and updates the non-volatile correction time (m, n) by copying the value obtained by subtracting the third correction time from the non-volatile correction time (m, n). As a result, the corrected power-on time is lengthened by the third correction time in steps S75 and S90. The control device 50 then proceeds to step S75.

[0055] If the process proceeds to step S75, the control device 50 reads out the non-volatile correction time (m, n) corresponding to the current operating region (m, n), copies the read value to the correction time, and then proceeds to step S80.

[0056] In step S80, the control device 50 sets the update processing in progress flag to OFF, sets the operation mode to 0, and proceeds to step S90. Note that the update processing in progress flag = OFF and the operation mode = 0 indicate that the correction time update process is not being performed.

[0057] <Correction time update process (Fig. 4)> After executing the "correction time update process" in step S45 shown in FIG. 3, the control device 50 advances the process to step U10 of the "correction time update process" shown in FIG.

[0058] In step U10, the control device 50 determines whether the operation mode is "1." If the operation mode is "1," the mode is for lengthening the correction time (a mode for shortening the current-carrying time after correction), and if the operation mode is "2," the mode is for shortening the correction time (a mode for lengthening the current-carrying time after correction). If the operation mode is "1" (Yes), the control device 50 proceeds to step U20, and if the operation mode is not "1" (No), the control device 50 proceeds to step U60.

[0059] If the process proceeds to step U20, the control device 50 determines whether the correction increase / decrease flag is ON. If the operation mode is "1" and the correction increase / decrease flag is ON, the correction time is lengthened, and if the operation mode is "2" and the correction increase / decrease flag is ON, the correction time is shortened. If the correction increase / decrease flag is ON (Yes), the control device 50 proceeds to step U55, and if the correction increase / decrease flag is not ON (No), the control device 50 proceeds to step U25.

[0060] If the process proceeds to step U25, the control device 50 increments the detection count by +1 and proceeds to step U30. The detection count is the number of times the Overall Process in FIG. 3 is started after the correction time is lengthened or shortened.

[0061] In step U30, the control device 50 determines whether the number of detections is two or more. The corrected energization time using the longer correction time (step U55) or the corrected energization time using the shorter correction time (step U95) is output to the ignition coil of the igniter at the start of the next [overall process] (when the number of detections = 1). The combustion stroke due to the corrected energization time affects the angular velocity ω of the crankshaft at the start of the next [overall process] (when the number of detections = 2). If the number of detections is two or more (Yes), the control device 50 proceeds to step U35. If the number of detections is less than two (No), the control device 50 ends the process shown in FIG. 4 and returns to step S90 in FIG. 3.

[0062] If the process proceeds to step U35, the control device 50 determines whether a misfire has occurred. As in step S65 of FIG. 3, the control device 50 determines that a misfire has occurred if the difference between the current angular velocity ω of the crankshaft and the angular velocity ω1 from the previous process (or the angular velocity ω4 from the fourth process before (in the case of a four-cylinder engine)) is equal to or greater than a predetermined amount. Note that the method for determining whether a misfire has occurred is not limited to determination based on the angular velocity ω, and any determination method may be used. If the control device 50 determines that a misfire has occurred (Yes), the process proceeds to step U50, and if it determines that a misfire has not occurred (No), the process proceeds to step U40.

[0063] If the process proceeds to step U40, the control device 50 determines whether the number of detections is 4+1 (=5) or more (in the case of four cylinders). For example, in the case of six cylinders, the control device 50 determines whether the number of detections is 6+1 (=7) or more. If the number of detections is 4+1 (=5) or more (Yes), it is determined that no misfires have been detected in cylinders 1 through 4 (that is, it is determined that no misfires have been detected in any of the cylinders), and the process proceeds to step U45. If the number of detections is less than 4+1 (=5), the process shown in FIG. 4 is terminated and the process returns to step S90 in FIG. 3 in order to detect a misfire in the next cylinder.

[0064] If the process proceeds to step U45, in the case of a four-cylinder engine, misfire was not detected in cylinders 1 through 4 (misfire was not detected in any of the cylinders), so the control device 50 sets the correction increase / decrease flag to ON in order to extend the correction time in step U55 during the next process and determine whether or not there is a misfire again, terminates the process shown in FIG. 4, and returns to step S90 in FIG. 3.

[0065] If the process proceeds to step U50, the control device 50 determines that a misfire has occurred in at least one cylinder, so it terminates operation mode 1 (a mode in which the first correction time is added to the correction time), sets the operation mode to "2", sets the correction increase / decrease flag to ON, terminates the process shown in Figure 4, and returns to step S90 in Figure 3.

[0066] If the process proceeds to step U55, the control device 50 will copy the value obtained by adding the first correction time to the correction time in operation mode 1, set the correction increase / decrease flag to OFF, set the number of detections to "0", terminate the process shown in Figure 4, and return to step S90 in Figure 3.

[0067] If the process proceeds to step U60, the control device 50 determines whether the correction increase / decrease flag is ON. If the operation mode is "1" and the correction increase / decrease flag is ON, the correction time is lengthened, and if the operation mode is "2" and the correction increase / decrease flag is ON, the correction time is shortened. If the correction increase / decrease flag is ON (Yes), the control device 50 proceeds to step U95, and if the correction increase / decrease flag is not ON (No), the control device 50 proceeds to step U65.

[0068] If the process proceeds to step U65, the control device 50 increments the detection count by +1 and then proceeds to step U70. The detection count is the number of times the Overall Process in FIG. 3 is started after the correction time is lengthened or shortened.

[0069] In step U70, the control device 50 determines whether the number of detections is two or more. The corrected energization time using the longer correction time (step U55) or the corrected energization time using the shorter correction time (step U95) is output to the ignition coil of the igniter at the start of the next [overall process] (when the number of detections = 1), and the combustion stroke due to the corrected energization time affects the angular velocity ω of the crankshaft at the start of the next [overall process] (when the number of detections = 2). If the number of detections is two or more (Yes), the control device 50 proceeds to step U75. If the number of detections is less than two (No), the control device 50 ends the process shown in FIG. 4 and returns to step S90 in FIG. 3.

[0070] If the process proceeds to step U75, the control device 50 determines whether a misfire has occurred. As in step S65 of FIG. 3, the control device 50 determines that a misfire has occurred if the difference between the current angular velocity ω of the crankshaft and the angular velocity ω1 from the previous process (or the angular velocity ω4 from the fourth process before (in the case of a four-cylinder engine)) is equal to or greater than a predetermined amount. Note that the method for determining whether a misfire has occurred is not limited to determination based on the angular velocity ω, and any determination method may be used. If the control device 50 determines that a misfire has occurred (Yes), the process proceeds to step U90, and if it determines that a misfire has not occurred (No), the process proceeds to step U80.

[0071] If the process proceeds to step U80, the control device 50 determines whether the number of detections is 4+1 (=5) or more (in the case of four cylinders). For example, in the case of six cylinders, the control device 50 determines whether the number of detections is 6+1 (=7) or more. If the number of detections is 4+1 (=5) or more (Yes), it is determined that no misfires have been detected in cylinders 1 through 4, and the process proceeds to step U85. If the number of detections is less than 4+1 (=5), the process shown in FIG. 4 is terminated and the process returns to step S90 in FIG. 3 in order to detect a misfire in the next cylinder.

[0072] When the process proceeds to step U85, since no misfire was detected in cylinders 1 through 4 in the case of a four-cylinder engine (no misfire was detected in any of the cylinders), the control device 50 ends the current application extension control (control in operation mode "2"), which subtracts the second correction time from the correction time to extend the post-correction current application time, and saves (updates) the correction time at the time of the end of the control operation in the non-volatile correction time (m, n). The control device 50 updates the non-volatile correction time (m, n) corresponding to the current operating range (m, n) by copying the correction time. Furthermore, the control device 50 initializes the post-update elapsed time (m, n) to zero, sets the update completion flag (m, n) to ON (updated), sets the update processing in progress flag to OFF (the correction time update process is terminated), and sets the number of detections to "0." The control device 50 then ends the process shown in FIG. 4 and returns to step S90 in FIG. 3.

[0073] If the process proceeds to step U90, the control device 50 determines that a misfire has occurred in at least one cylinder, so it sets the correction increase / decrease flag to ON in order to subtract the second correction time from the correction time again, terminates the process shown in Figure 4, and returns to step S90 in Figure 3.

[0074] If the process proceeds to step U95, the control device 50 copies the value obtained by subtracting the second correction time from the correction time in operation mode 2 to the correction time, since this is the timing to subtract the second correction time from the correction time. Furthermore, the control device 50 sets the correction increase / decrease flag to OFF, sets the number of detections to "0", ends the process shown in Fig. 4, and returns the process to step S90 in Fig. 3.

[0075] <Processing of elapsed time since update (Figure 5)> The control device 50 starts the "processing of post-update elapsed time" shown in FIG. 5 at predetermined time intervals (for example, every few seconds), and advances the process to step X10.

[0076] In step X10, the control device 50 counts up all of the post-update elapsed times (m, n) by +1 and ends the process. The post-update elapsed times (m, n) indicate the time elapsed since the non-volatile correction times (m, n) corresponding to the operating ranges (m, n) were updated.

[0077] <Power start setting process (Fig. 6)> The control device 50 starts the "energization start setting process" shown in Fig. 6 at the timing when the energization timer for starting energization of the ignition coil of the igniter is set, and the process proceeds to step Y10. Note that since the "energization start setting process" is an existing process, details will be omitted and an outline will be given.

[0078] In step Y10, the control device 50 predicts the power distribution end time, sets the power distribution start time in the power distribution timer so that power distribution starts from a time (power distribution start time) that is earlier than the power distribution end time by the corrected power distribution time, and then ends the processing.

[0079] <Power termination setting process (Fig. 7)> The control device 50 starts the "energization termination setting process" shown in Fig. 7 at the timing when the energization timer for terminating the energization of the ignition coil of the igniter is set, and the process proceeds to step Z10. Note that since the "energization termination setting process" is an existing process, details will be omitted and an outline will be given.

[0080] In step Z10, the control device 50 acquires the power supply start time, sets the power supply end time in the power supply timer so that the power supply will end at the time (power supply end time) after the corrected power supply time has elapsed from the power supply start time, and ends the processing.

[0081] <Example of Operation Waveforms of the First Embodiment (Example 1) (FIG. 10)> FIG. 10 shows an example of an operational waveform (Example 1) according to the processing of the control device 50 of the first embodiment. FIG. 10 shows an example of a four-cylinder internal combustion engine, and the "requested energization time for cylinder 1" to the "requested energization time for cylinder 4" show that the requested energization times gradually increase as deterioration progresses over time, indicating that they differ due to individual differences and variations. For example, when the "corrected energization time" is longer than the "requested energization time for cylinder 1," this indicates that a spark is normally generated from the spark plug of cylinder 1, and when the "corrected energization time" is shorter than the "requested energization time for cylinder 1," a normal spark is not normally generated from the spark plug of cylinder 1, resulting in a misfire. FIG. 10 also shows an example of the operating state of the internal combustion engine in the operating region (2, 2) shown in FIG. 8.

[0082] At time T11 (and times T21, T31, and T41) in FIG. 10, the conditions for updating the correction time are satisfied, and steps S30 to S45 of the "Overall Processing" shown in FIG. 3 and the "Correction Time Update Processing" shown in FIG. 4 are initiated, and the "Update Processing In Progress Flag" is turned ON. Then, from time T11 to time T13 (and times T21 to T23, T31 to T33, and T41 to T43), in operation mode "1," current application reduction control is executed, which temporarily shortens the corrected current application time by temporarily lengthening the correction time until at least one cylinder misfires. Steps U20 to U55 in FIG. 4 correspond to the current application reduction control. In the current application reduction control, the control device 50 adds the first correction time to the correction time (subtracts the first correction time from the corrected current application time) to determine whether or not a misfire has occurred. If none of the cylinders misfire, the control device 50 again adds the first correction time to the correction time and repeats the process of determining whether or not a misfire has occurred.

[0083] At time T13 in FIG. 10 (and times T23, T33, and T43), misfire is detected in at least one cylinder, so the current reduction control of operation mode "1" is terminated, and operation mode "2" is entered, in which current extension control is initiated, which temporarily extends the corrected current time by temporarily shortening the correction time until all cylinders no longer misfire. Steps U60 to U95 in FIG. 4 correspond to the current extension control. In the current extension control, the control device 50 subtracts the second correction time from the correction time (adds the second correction time to the corrected current time) to determine whether or not misfire has occurred, and if at least one cylinder has misfired, the control device 50 subtracts the second correction time from the correction time again to repeat the process of determining whether or not misfire has occurred. The example in Figure 10 shows cases where all cylinders did not misfire simply by shortening the correction time by the second correction time once (time T13 to time T14, time T23 to time T24, time T33 to time T34, time T43 to time T44).

[0084] 10, because none of the cylinders misfired during the current extension control following the current reduction control, the current extension control for operation mode "2" is terminated and correction time update control is executed to update the correction time to a new correction time. At time T14 (and time T24, time T34, time T44), the control device 50 copies the value of the correction time to the non-volatile correction time (2, 2) corresponding to the operating region (2, 2), initializes the post-update elapsed time (2, 2) to zero, sets the update completion flag (2, 2) to ON, and sets the update processing in progress flag to OFF (the correction time update processing has ended).

[0085] <Example of Operation Waveforms in the First Embodiment (Example 2) (FIG. 11)> Figure 11 shows an example in which the first correction time is greater than the second correction time, as compared to the example (Example 1) of the operating waveforms shown in Figure 10 (first correction time < second correction time), and shows an example in which a misfire occurred (times T56 and T66) even when the update process for the correction time to intentionally cause a misfire was not being executed (update process in progress flag = ON). The following mainly describes the differences from (Example 1) of Figure 10.

[0086] 11, the "correction time update process" shown in FIG. 4 is started, and the "update process in progress flag" is turned ON. Then, the control device 50 repeats adding the first correction time to the correction time and determining whether or not a misfire has occurred during the current reduction control of operation mode "1" (times T51 to T53, time T61 to T63, time T71 to T73) until a misfire is detected in at least one cylinder.

[0087] From time T52 to time T53 (and time T61 to time T63, time T71 to time T73) in Figure 11, the control device 50 detects misfire in at least one cylinder, so it terminates the current reduction control, transitions to operating mode "2", and from time T53 to time T54 (and time T63 to time T64, time T73 to time T74), it repeats subtracting the second correction time from the correction time to determine misfire until all cylinders no longer misfire.

[0088] At time T56 (and time T66) in Fig. 11, a misfire occurs when the [correction time update process] is not being performed to intentionally cause a misfire (when the update process in progress flag is OFF). In this case, in steps S60 to S80 of the [overall process] in Fig. 3, the control device 50 updates the non-volatile correction time (2, 2) obtained by subtracting the third correction time from the non-volatile correction time (2, 2) to a new non-volatile correction time (2, 2), and copies the updated non-volatile correction time (2, 2) to the correction time in step S75.

[0089] In other words, when a misfire occurs in at least one cylinder during normal control when the [correction time update process] is not being executed (when the correction time update conditions are not satisfied), the control device 50 shortens the correction time by the third correction time (lengthens the corrected current application time by the third correction time) to prevent the misfire from continuing.

[0090] <Processing Procedures of the Control Device 50 in the Second Embodiment (FIGS. 12 to 15)> <Correction time update process (Figure 12)> Next, the processing of the control device 50 (CPU 51) in the second embodiment will be described with reference to Figures 12 to 15. Note that the second embodiment differs from the first embodiment in that the "correction time update processing" shown in Figure 4 is changed to the "correction time update processing" shown in Figure 12, and the "accumulated operation time processing" shown in Figure 13 is added. The "overall processing" shown in Figure 3 and the processing shown in Figures 5, 6, and 7 are the same as those in the first embodiment. Below, the differences from the first embodiment will be mainly described.

[0091] After executing the "correction time update process" of step S45 shown in FIG. 3, the control device 50 advances the process to step V10 of the "correction time update process" shown in FIG.

[0092] In step V10, the control device 50 acquires the cumulative operating time, acquires a fourth correction time corresponding to the cumulative operating time based on the cumulative operating time and the cumulative operating time vs. fourth correction time characteristic shown in FIG. 14, and proceeds to step V20. The fourth correction time is set to be shorter as the cumulative operating time increases. In the subsequent processing, if the update condition for the correction time is satisfied, the control device 50 temporarily sets the correction time to the fourth correction time and determines whether or not a misfire has occurred. If none of the cylinders has misfired, the control device 50 updates the correction time and non-volatile correction time (m, n) to the fourth correction time. If at least one cylinder has misfired, the control device 50 cancels the update of the correction time and non-volatile correction time (m, n) and retains the values.

[0093] In step V20, the control device 50 determines whether the correction increase / decrease flag is ON. If the correction increase / decrease flag is ON, the control device 50 sets the correction time to the fourth correction time. If the correction increase / decrease flag is ON (Yes), the control device 50 proceeds to step V55, and if the correction increase / decrease flag is not ON (No), the control device 50 proceeds to step V25.

[0094] If the process proceeds to step V25, the control device 50 counts up the number of detections by +1 and proceeds to step V30. The number of detections is the number of times the "Overall Process" in FIG. 3 is started after the correction time is set to the fourth correction time.

[0095] In step V30, the control device 50 determines whether the number of detections is 2 or greater. The corrected energization time, in which the correction time is set to the fourth correction time (step V55), is output to the ignition coil of the igniter at the start of the next [overall processing] (when the number of detections = 1), and the combustion stroke due to this corrected energization time affects the angular velocity ω of the crankshaft at the start of the next [overall processing] (when the number of detections = 2). If the number of detections is 2 or greater (Yes), the control device 50 proceeds to step V35. If the number of detections is less than 2 (No), the control device 50 ends the processing shown in FIG. 12 and returns to step S90 in FIG. 3.

[0096] If the process proceeds to step V35, the control device 50 determines whether or not a misfire has occurred. As in step S65 of FIG. 3, for example, the control device 50 determines that a misfire has occurred if the difference between the current angular velocity ω of the crankshaft and the angular velocity ω1 from the previous process (or the angular velocity ω4 from the fourth process before (in the case of a four-cylinder engine)) is equal to or greater than a predetermined amount. Note that the method for determining whether a misfire has occurred is not limited to determination based on the angular velocity ω, and any determination method may be used. If the control device 50 determines that a misfire has occurred (Yes), the process proceeds to step V50, and if it determines that a misfire has not occurred (No), the process proceeds to step V40.

[0097] When the process proceeds to step V40, the control device 50 determines whether the number of detections is 4+1 (=5) or more (in the case of four cylinders). For example, in the case of six cylinders, the control device 50 determines whether the number of detections is 6+1 (=7) or more. If the number of detections is 4+1 (=5) or more (Yes), it is determined that no misfires have been detected in cylinders 1 through 4 (that is, it is determined that no misfires have been detected in any of the cylinders), and the process proceeds to step V45. If the number of detections is less than 4+1 (=5), the process shown in FIG. 12 is terminated and the process returns to step S90 in FIG. 3 in order to detect a misfire in the next cylinder.

[0098] When the process proceeds to step V45, in the case of a four-cylinder engine, no misfire was detected in cylinders 1 through 4 (no misfire was detected in any of the cylinders), so the control device 50 saves (updates) the fourth correction time (corresponding to the predetermined correction time) in the non-volatile correction time (m, n) before ending the process shown in FIG. 12. The control device 50 updates the non-volatile correction time (m, n) corresponding to the current operating range (m, n) by copying the correction time, initializes the post-update elapsed time (m, n) to zero, sets the update completion flag (m, n) to ON (updated), sets the update processing in progress flag to OFF (ends the correction time update process), and sets the number of detections to "0." The control device 50 then ends the process shown in FIG. 12 and returns to step S90 in FIG. 3.

[0099] If the process proceeds to step V50, the control device 50 stops setting the fourth correction time to the correction time because a misfire has occurred in at least one cylinder, and returns the correction time to the state before the update process. The control device 50 copies the non-volatile correction time (m, n) corresponding to the current operating range (m, n) to the correction time, initializes the post-update elapsed time (m, n) to zero, sets the update process in progress flag to OFF (terminating the update process of the correction time), and sets the detection count to "0". The control device 50 then ends the process shown in FIG. 12 and returns the process to step S90 in FIG. 3.

[0100] If the process proceeds to step V55, the control device 50 copies the fourth correction time to the correction time, sets the correction increase / decrease flag to OFF, sets the number of detections to "0", terminates the process shown in Figure 4, and returns to step S90 in Figure 3.

[0101] <Cumulative operating time processing (Fig. 13)> The control device 50 starts the "processing of accumulated operating time" shown in FIG. 13 at predetermined time intervals (for example, every few seconds), and proceeds to step R10.

[0102] In step R10, the control device 50 counts up the cumulative operating time by 1 and ends the process. The cumulative operating time is stored in a nonvolatile storage device, and the cumulative operating time of the internal combustion engine is stored.

[0103] <Example of Operation Waveforms of the Second Embodiment (Example 3) (FIG. 15)> FIG. 15 shows an example (Example 3) of the operating waveforms of the second embodiment when the [correction time update process] is changed from the process shown in FIG. 4 to the process shown in FIG. 12 (and FIG. 13) under the same conditions as in FIG. 10 (the internal combustion engine has four cylinders and the operating state of the internal combustion engine is in the operating region (2, 2)).

[0104] As shown in Fig. 15, the second embodiment differs in that the "correction time update process" does not shorten the post-correction power supply time until at least one cylinder misfires, but determines whether or not the fourth correction time calculated based on the cumulative operating time and the cumulative operating time vs. fourth correction time characteristic (see Fig. 14) can be used as the correction time. The following mainly describes the differences from the first embodiment (see Figs. 10 and 11).

[0105] At time T81 (and time T91, time TA1, and time TC1) in FIG. 15, the update conditions for the correction time are satisfied, and steps S30 to S45 of the overall process shown in FIG. 3 and the correction time update process shown in FIG. 12 are started, and the "update process in progress flag" is turned ON. When the correction time update process starts, the control device 50 acquires a fourth correction time based on the cumulative driving time vs. fourth correction time characteristic shown in FIG. 14 and the cumulative driving time, and temporarily sets the acquired fourth correction time as the correction time. Note that the fourth correction time corresponds to a predetermined correction time. Furthermore, instead of the cumulative driving time vs. fourth correction time characteristic, a cumulative mileage vs. fourth correction time characteristic may be similarly set, and the fourth correction time may be acquired based on the cumulative mileage and the cumulative mileage vs. fourth correction time characteristic.

[0106] At time T82 (and time T92, time TA2) in Figure 15, the control device 50 temporarily sets the correction time to the fourth correction time in the [correction time update process] (step V55 in Figure 12), and since none of the cylinders misfired, executes correction time update control to update the fourth correction time to a new correction time, copies the correction time to the non-volatile correction time (2, 2), and updates the non-volatile correction time (2, 2) (step V45 in Figure 12).

[0107] At time TB1 (and time TD1) in Fig. 15, a misfire occurs when the [correction time update process] is not being performed (when the update process in progress flag is OFF). In this case, the control device 50 updates the non-volatile correction time (2, 2) obtained by subtracting the third correction time from the non-volatile correction time (2, 2) to a new non-volatile correction time (2, 2) in steps S60 to S80 in the [overall process] in Fig. 3, and copies the updated non-volatile correction time (2, 2) to the correction time in step S75.

[0108] Between time TC1 and time TC2 in FIG. 15, the control device 50 temporarily set the correction time to the fourth correction time in the [correction time update process], but because a misfire occurred in at least one cylinder, the correction time was not changed to the fourth correction time, and the correction time was returned to the correction time immediately before time TC1 (step V50 in FIG. 12).

[0109] <Effects etc.> As described above, in the first and second embodiments, the "corrected time update process" temporarily shortens the time that the ignition coil of the igniter is energized to determine whether or not a misfire has occurred, thereby reducing the margin for individual differences and variations in the ignition coil and spark plug, and more appropriately shortening the time that the ignition coil of the igniter is energized (corrected energization time). This makes it possible to further prevent the life of the spark plug from being shortened.

[0110] In addition, in the first and second embodiments, if a misfire occurs when the [correction time update process] is not being performed, the time during which current is applied to the ignition coil of the igniter (corrected current application time) is lengthened, thereby preventing the misfire from continuing.

[0111] In the first embodiment, in the "correction time update process," the corrected energization time is shortened (the correction time is lengthened) until at least one cylinder misfires, and then the corrected energization time is lengthened (the correction time is shortened) until all cylinders no longer misfire. This makes it possible to determine a corrected energization time that is shorter to avoid misfires and that has a smaller margin that takes into account individual differences and variations. In the second embodiment, the corrected energization time cannot be shortened as much as in the first embodiment with simpler control than in the first embodiment, but it can be made shorter than conventional methods.

[0112] <Other> The ignition control system 2 for an internal combustion engine of the present invention is not limited to the configuration, structure, processing procedures, etc. described in this embodiment, and various modifications, additions, and deletions are possible within the scope that does not change the gist of the present invention.

[0113] The internal combustion engine ignition control system 2 of the present invention is not limited to vehicles equipped with gasoline engines, but can also be applied to spark-ignition internal combustion engines that use gasoline, natural gas, alcohol (including mixed fuels of gasoline and alcohol), hydrogen, etc. as fuel.

[0114] The first correction time, second correction time, third correction time, fourth correction time, predetermined time, etc. described in this embodiment are set to appropriate values ​​evaluated through experiments and simulations using an actual vehicle.

[0115] In the description of this embodiment, an example has been described in which a plurality of operating regions (m, n) are set according to the operating state of the internal combustion engine, and each operating region (m, n) has a non-volatile correction time (m, n), a time elapsed since update (m, n), and an update completion flag (m, n). However, in the case of an internal combustion engine for a heat pump, where the operating state of the internal combustion engine is kept almost constant, only one operating region (m, n) may be used.

[0116] In the description of this embodiment, the correction time and non-volatile correction time (m, n) are used in common for each cylinder, but the correction time and non-volatile correction time (m, n) may be set for each cylinder so that the corrected current supply time has a different value for each cylinder.

[0117] Furthermore, when expressions such as "greater than or equal to (≧)," "less than or equal to (≦)," "greater than," "exceeds (>)," and "less than (<)" are used, the equal sign may or may not be included. Furthermore, when numerical values ​​are used in the description of this embodiment, they are merely examples and are not limited to these numerical values. [Explanation of symbols]

[0118] 1 Internal combustion engine system 2. Ignition control system 10 Internal combustion engine 11A, 11C intake pipe 11D Intake manifold 12A Exhaust manifold 12B, 12C, 12D, 12E exhaust pipes 13 EGR piping 13A EGR valve 21 Injector 31 Air flow detection device 32A, 32B Intake air temperature detection device 32C Coolant temperature detector 33A Atmospheric pressure detector 34A Rotation detector 34B Cylinder detection device 38 Accelerator pedal depression amount detection device 39 Ignition switch 40 Exhaust gas purification device 48 A / F detector 50 Control device 51 CPU 52 RAM 53 ROM 54 Timer 55 Non-volatile storage 56A constant voltage power supply 64 Throttle device 64A motor 64B Opening detection device 71 Spark plug 72 Igniter 72A drive circuit 72B Ignition confirmation signal generating circuit 72C Primary coil (ignition coil) 72D Secondary coil (ignition coil) P1, P2 pulse

Claims

1. An ignition control system for an internal combustion engine having a spark plug provided for each cylinder, an ignition coil provided for each of the spark plugs and supplying electrical energy to the spark plug, and a control device for controlling each of the ignition coils, The control device controlling each of the ignition coils based on a corrected current conduction time obtained by subtracting a correction time from a base current conduction time set based on an operating state of the internal combustion engine; If the update condition for the correction time is satisfied, a correction time update control is executed to temporarily set a predetermined correction time as the correction time, the correction time being shorter than the base current time, to control each of the ignition coils based on the corrected current time, and to determine whether or not a misfire has occurred in each cylinder, and if no misfire has occurred in any of the cylinders, to update the predetermined correction time to a new correction time; Ignition control system for internal combustion engines.

2. An ignition control system for an internal combustion engine having a spark plug provided for each cylinder, an ignition coil provided for each of the spark plugs and supplying electrical energy to the spark plug, and a control device for controlling each of the ignition coils, The control device controlling each of the ignition coils based on a corrected current conduction time obtained by subtracting a correction time from a base current conduction time set based on an operating state of the internal combustion engine; If the update condition for the correction time is satisfied, executing a current supply reduction control for temporarily shortening the corrected current supply time by temporarily lengthening the corrected time until at least one cylinder misfires; When at least one cylinder misfires during the current reduction control, the current reduction control is terminated, and current extension control is executed to temporarily extend the corrected current reduction time by temporarily shortening the correction time until all cylinders no longer misfire, If no misfire occurs in any of the cylinders during the current extension control after the current reduction control, the current extension control is terminated, and the correction time at the time of termination is updated to a new correction time. Ignition control system for internal combustion engines.

3. 3. An ignition control system for an internal combustion engine according to claim 2, The control device When the corrected energization time is temporarily shortened in the energization shortening control, adding a first correction time to the correction time to determine whether or not a misfire has occurred in each cylinder; If none of the cylinders has misfired, the first correction time is added to the correction time again, and the determination of whether or not each cylinder has misfire is repeated. Ignition control system for internal combustion engines.

4. 3. An ignition control system for an internal combustion engine according to claim 2, The control device When the corrected current supply time is temporarily extended by the current supply extension control, Subtracting a second correction time from the correction time to determine whether or not a misfire has occurred in each cylinder; If at least one cylinder misfires, the second correction time is subtracted from the correction time again, and the determination of whether or not each cylinder misfires is occurring is repeated. Ignition control system for internal combustion engines.

5. An ignition control system for an internal combustion engine according to any one of claims 1 to 4, the correction time is set for each of a plurality of operating regions according to the operating state of the internal combustion engine, The control device The corrected current application time is calculated using the corrected time in the operating region according to the operating state. If the update condition for the correction time is satisfied, executing the correction time update control for the correction time in the operating region according to the operating state, and updating the correction time in which no cylinder misfires to a new correction time in the operating region; Ignition control system for internal combustion engines.

6. An ignition control system for an internal combustion engine according to any one of claims 1 to 4, The control device If the update condition of the correction time is not satisfied, controlling each of the ignition coils based on the corrected current conduction time obtained by subtracting the correction time from the base current conduction time, and determining whether or not a misfire has occurred in each cylinder when a misfire detection condition is satisfied, and updating the correction time obtained by subtracting a third correction time from the correction time to a new correction time when a misfire has been detected in at least one cylinder; Ignition control system for internal combustion engines.

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