JP2008025405A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for an internal combustion engine for properly preventing the occurrence of knocking while suppressing torque fluctuation. <P>SOLUTION: The control device for the internal combustion engine is provided with a knocking detection means 54 for detecting the occurrence of knocking, an ignition timing retarding means for retarding ignition timing when the occurrence of knocking is detected by the knocking detection means 54, and an ozone supply means 44 for performing supply of ozone so as to supply the ozone into a cylinder 20 when the ignition timing is retarded by the ignition timing retarding means. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a control device for an internal combustion engine that avoids knocking while suppressing torque fluctuation.

  Conventionally, when self-ignition, that is, so-called knocking occurs in the air-fuel mixture in the engine combustion chamber, for example, control for retarding the ignition timing by the spark plug is performed in order to avoid the occurrence of this knocking.

  Further, for example, Patent Document 1 includes a fuel supply unit that supplies fuel directly into a cylinder and an ozone supply unit that supplies ozone directly into the cylinder, and both the fuel supply unit and the ozone supply unit are provided. A self-igniting engine that is configured to operate during a compression stroke is disclosed. In this self-ignition engine, the amount of ozone supplied into the cylinder is reduced when the knocking intensity detected by the knocking detection means is higher than the limit value.

  On the other hand, Patent Document 2 discloses a combustion stability detecting means for detecting combustion stability, and negative gas in which burned gas is confined in the cylinder by closing both the exhaust valve and the intake valve near the exhaust top dead center. A compression self-ignition internal combustion engine is disclosed that includes control means for extending the overlap period and ignition auxiliary means for urging ignition. In this internal combustion engine, when combustion stability deteriorates, the negative overlap period is extended in accordance with the decrease in engine load, and ignition assist is provided when the engine load is below a predetermined judgment point in the low load region. Means are activated to prompt ignition. The ignition assisting means promotes ignition by advancing the intake valve closing timing to increase the substantial compression ratio or supplying ozone.

JP 2002-309941 A JP 2003-003873 A

  As described above, when the ignition timing is retarded to avoid the occurrence of knocking, the torque is reduced due to the ignition timing retardation. This is a torque fluctuation that is not desired by the driver or the like and is not preferable.

  Accordingly, an object of the present invention is to provide a control device for an internal combustion engine that appropriately avoids knocking while suppressing torque fluctuation.

  In order to solve the above-described problems, a control apparatus for an internal combustion engine according to the present invention includes a knocking detection unit that detects or estimates the occurrence of knocking, and an ignition timing when the occurrence of knocking is detected or estimated by the knocking detection unit. Ignition timing retarding means for retarding the ignition timing, and ozone supply means for supplying ozone so that ozone is supplied into the cylinder when the ignition timing is retarded by the ignition timing retarding means. It is characterized by that.

  According to the above configuration, when the occurrence of knocking is detected or estimated by the knocking detection means, the ignition timing is retarded by the ignition timing retarding means, so that it is possible to appropriately avoid the occurrence of knocking. Further, when the ignition timing is retarded by the ignition timing retarding means, the ozone supply is executed so that ozone is supplied into the cylinder by the ozone supply means, so that combustion of the air-fuel mixture is promoted. Therefore, sufficient combustion of the air-fuel mixture is performed in a shorter time, and torque improvement corresponding to the amount of supplied ozone can be achieved. Therefore, it is possible to compensate for the torque decrease due to the ignition timing retardation by the torque improvement by the ozone supply as described above, and it is possible to suppress the torque fluctuation of the internal combustion engine when the occurrence of knocking is avoided.

  In particular, it is preferable that the amount of ozone supplied by the ozone supply means corresponds to the ignition delay amount by the ignition timing delay means. As a result, it is possible to make the torque decrease due to the ignition timing retardation substantially equal to the torque improvement due to the ozone supply.

  Further, in addition to the above configuration, a failure determination unit that determines a failure of the ozone supply unit, and when the failure determination unit determines a failure of the ozone supply unit, it corresponds to the amount of ozone that is scheduled to be supplied. It is preferable to further include intake air amount increasing means for increasing the intake air amount by the amount of intake air. When the failure determination means determines that the ozone supply means has failed, the intake air amount increase means increases the intake air amount corresponding to the amount of ozone scheduled to be supplied. The torque improvement expected by the ozone supply can be achieved by increasing the torque by increasing the intake air amount.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a conceptual diagram of a vehicle engine system to which the control device for an internal combustion engine of the present embodiment is applied. The internal combustion engine (engine) 10 of the present embodiment is a port injection type spark ignition internal combustion engine.

  In the engine 10, air (intake air) drawn from the intake port is introduced into the intake passage 14 via the air cleaner 12. The air flows into the surge tank 18 while the flow rate is adjusted by the opening degree of the throttle valve 16, and is divided into intake manifolds 22 that are branched corresponding to the cylinders 20. However, in the engine 10, the depression operation of an accelerator pedal (not shown) and the opening / closing operation of the throttle valve 16 can be separated and electronically controlled. The intake passage 14 is formed by a surge tank 18, an intake manifold 22, an intake pipe 23 connected upstream of them, and the like. A fuel injection valve 24 is disposed in the intake manifold 22. The fuel injected by the fuel injection valve 24 is mixed with the diverted air, and an ignition plug 30 that is operated by the control of the ignition coil 28 via the intake valve 26 is provided in the combustion chamber 32 provided in the upper center. Inhaled.

  In the combustion chamber 32 of each cylinder 20, the air-fuel mixture is ignited by a spark plug 30. A flame generated by the ignition gradually propagates to the entire air-fuel mixture, and the air-fuel mixture usually burns. Exhaust gas generated by the combustion is discharged through an exhaust valve 34 to an exhaust manifold 36 that is branched corresponding to each cylinder 20. The exhaust gas is purified by passing through a catalytic converter 42 disposed in the middle of an exhaust pipe 40 that defines an exhaust passage 38 together with the exhaust manifold 36 and the like, and is discharged into the atmosphere.

  In the present embodiment, the valve operating mechanism (not shown) for opening and closing the intake valve 26 and the exhaust valve 34 is capable of freely changing the phase of the working angle (operating angle) of the intake valve 26 and the exhaust valve 34 and the lift amount. That is, it is a variable valve mechanism that makes the valve timing freely variable and the lift amount freely variable. This valve operating mechanism moves the intake valve 26 and the exhaust valve 34 by the electromagnetic force of the electromagnetic coil, and these intake / exhaust valves 26 and 34 are electromagnetically driven valves. Therefore, the phase of the working angle and the lift amount can be freely changed by the electromagnetic force by the energization drive controlled by the electromagnetic coils of the intake valve 26 and the exhaust valve 34.

Further, ozone supply means 44 is provided that supplies ozone so that ozone (O ₃ ) is supplied into the cylinder 20, that is, supplies ozone so that the mixture before combustion contains ozone. It has been. The ozone supply means 44 has an ozone generator 46, and ozone generated by the ozone generator 46 is supplied to the portion of the intake passage 14 on the downstream side of the throttle valve 16 in this embodiment. Specifically, the ozone generator 46 is configured to include a pump, a discharger, and a pulse power source, and serves as a part of the ozone supply means 44. The electronic control unit (ECU), which will be described later. It is operated by 48 control outputs. The ozone generator 46 removes dust and the like in the discharger, takes in air from the outside by a pump, and generates corona discharge between a pair of electrodes in the discharger by power supply from a pulse power source. Thereby, corona discharge acts on the air in the discharger, and ozone which is a kind of oxygen active component is generated. More specifically, electrons collide with oxygen molecules (O ₂ ) in the air to generate oxygen atoms, which combine with the oxygen molecules to generate ozone. The ozone generated in this way is supplied to the intake passage 14 via a discharge passage 50 having a nozzle shape that constitutes a part of the ozone supply means 44, and is introduced through the air cleaner 12 (intake air). And mix. However, the ozone generator 46 controls the power supplied to the discharger to an appropriate value so that a predetermined amount of ozone is generated and supplied. In the present embodiment, the pulse power source includes a battery in which electricity generated by the alternator using the power from the engine 10 is stored.

In order to perform fuel injection control, ignition timing control, ozone supply control, etc., the ECU 48 is provided as described above. The ECU 48 is constituted by a microcomputer including a CPU, a ROM and a RAM for recording various programs and data, an input interface circuit, and an output interface circuit. In the input interface circuit, a knock sensor 54 for detecting high-frequency vibration due to knocking transmitted to the cylinder block 52, and an ozone sensor 56 for detecting the ozone concentration are disposed downstream of the location where the ozone supply means 44 is connected. , An intake pressure sensor 58 for detecting the intake pressure downstream of the throttle valve 16, a throttle position sensor 60 for detecting the opening of the throttle valve 16, and an accelerator pedal depression amount, that is, an accelerator opening. An accelerator position sensor 62 for detecting the crank rotation signal of a crankshaft 66 provided on the cylinder block 52 and connected to the piston 64 via a connecting rod is provided on the cylinder block 52. The engine 10 the water temperature sensor 70 for detecting the temperature of cooling water (cooling water temperature) of, such as O ₂ sensor 72 for detecting the oxygen concentration in the exhaust gas flowing through upstream of the catalytic converter 42 via an electrical wiring connection Has been. In the present embodiment, the crank position sensor 68 is used as a rotational speed sensor for detecting the rotational speed (rotational speed) of the engine 10. The output interface circuit of the ECU 48 is connected to the fuel injection valve 24, the ignition coil 28 incorporating the igniter, the valve mechanism, the ozone generator 46, the throttle actuator 74 that operates the throttle valve 16, and the like. Based on data obtained by various sensors or the like, they can be controlled.

  In the engine 10, during normal operation, the intake pressure based on the output signal from the intake pressure sensor 58, the engine speed based on the output signal from the crank position sensor 68, that is, the operation expressed by the engine load and the engine speed. Based on the state, the basic fuel injection amount, the basic fuel injection timing, the basic ignition timing, and the like are set by searching data stored in the ROM in advance. Then, these basic values are corrected by the cooling water temperature of the engine 10, etc., and the fuel injection amount, fuel injection timing, ignition timing, etc. targeted for control are derived, and the operation of the fuel injection valve 24, the ignition plug 30, etc. Is controlled.

  Specifically, the ECU 48 of the engine 10 comprehensively determines the state of the engine 10 based on the driving state, and calculates the basic ignition timing obtained by searching data stored in the ROM in advance, such as knocking correction. To correct the advance or retard to determine the optimal ignition timing. Then, by sending an ignition signal to the igniter, the air-fuel mixture is ignited at the determined ignition timing.

  Further, in the engine 10, the valve mechanism is controlled by the ECU 48 so that a predetermined amount of overlap between the intake valve 26 and the exhaust valve 34 occurs when the engine speed and load are high during normal operation. It is controlled. Thereby, the air is effectively guided into the combustion chamber 32. On the other hand, during normal operation and when the engine speed and load are low, the above-described operation is performed in order to prevent the exhaust gas from flowing backward from the exhaust passage 38 into the combustion chamber 32 and causing unstable combustion. The valve operating mechanism is controlled so that the amount of overlap is smaller than that sometimes, or the overlap does not occur. The reason why the intake / exhaust valves 26 and 34 are controlled in this way is that, based on the valve timing during normal operation, data based on the operation state is obtained in advance through experiments and stored in the ROM. Note that such valve timing is generally set so that knocking does not occur and high drivability is ensured.

  Next, control for suppressing, ie, avoiding, the occurrence of knocking in the present embodiment will be described.

  In the ignition timing control, when the knocking occurs or is likely to occur, the ignition timing retarding control is performed to retard the ignition timing in order to avoid the occurrence of knocking. In this control, the occurrence of knocking is determined based on the output signal from the knock sensor 54. That is, when high-frequency vibration due to knocking is detected using the knock sensor 54, a predetermined ignition delay angle is determined from the basic ignition timing. The ignition timing is set to the ignition timing retarded by the amount. Preferably, the ignition timing is set after compression top dead center. The ignition timing retarding means for retarding the ignition timing in order to avoid the occurrence of knocking includes an ignition coil 28 and a spark plug 30, and a part of the functions is carried by the ECU 48.

  Then, while performing this ignition timing retardation control, the ECU 48 performs ozone supply control for causing the ozone generator 46 to generate and supply a predetermined amount of ozone. As a result, a predetermined amount of ozone is supplied to the intake passage 14. However, in order to prevent the amount of air sucked into the cylinder from increasing with the ozone supply, the throttle actuator 74 is used to reduce the opening of the throttle valve 16 so as to reduce the amount of air corresponding to the amount of ozone. Control is performed. When knocking occurs, the engine 10 is generally in a predetermined operation state of high rotation or medium / high load. Therefore, the throttle valve 16 is fully opened before the control for avoiding the occurrence of knocking is performed. In this embodiment, together with the ignition retard amount, the ozone supply amount is determined and stored in a predetermined amount corresponding to the ignition retard amount, and the opening degree of the throttle valve 16 is determined in advance to an amount corresponding thereto. Stored in the ROM. Therefore, when the occurrence of knocking is detected, in addition to retarding the ignition timing by a predetermined ignition delay amount, a predetermined amount of ozone is supplied, and an intake air amount corresponding to the predetermined amount is supplied. The opening of the throttle valve 16 is reduced.

  By supplying ozone, the air-fuel mixture in the combustion chamber 32 becomes chemically active. Therefore, the flame propagation in the air-fuel mixture is promoted, and the air-fuel mixture burns quickly. That is, the time from ignition to combustion is shortened. When ignition timing retarding control is performed to avoid knocking, the flame is generated by ignition at several degrees after compression top dead center, for example, 1 to 3 °, and propagates properly before the piston 64 is greatly lowered. Sufficient combustion pressure due to rapid combustion is exerted on the upper surface of the piston 64. Therefore, torque can be improved by supplying ozone, and this torque improvement can compensate for the torque reduction due to combustion deterioration at the ignition timing retardation. In addition, since combustion is performed quickly and appropriately by supplying ozone, it is possible to prevent deterioration in fuel consumption and exhaust emission due to retarded ignition timing.

  Furthermore, since the ignition timing is retarded while supplying ozone in this way, the ignition retard amount can be made larger than when ozone is not supplied. Therefore, it is possible to more reliably avoid the occurrence of knocking. However, it is preferable that the supplied ozone amount and the ignition retard amount correspond to each other so as not to cause torque fluctuation.

  FIG. 2 conceptually shows a series of control flow for avoiding such knocking. Hereinafter, a description will be given with reference to FIG.

  Schematically, the ECU 48 first determines whether or not knocking has occurred based on whether or not high-frequency vibration due to knocking has been detected based on an output signal from the knock sensor 54 (step S201). If it is determined that knocking has not occurred and the result is negative, ignition timing retard control for avoiding knocking is stopped (step S203), and ozone supply control is stopped (step S205). ). When the ozone supply control is stopped at this time, the control for reducing the opening of the throttle valve 16 is also stopped, and the opening of the throttle valve 16 is not reduced. On the other hand, if it is determined that knocking has occurred and the determination is affirmative (step S201), ignition timing retarding control is performed (step S207), and ozone supply control is performed almost simultaneously (step S209). When the ozone supply is executed, as described above, the opening of the throttle valve 16 is also reduced to reduce the intake air amount corresponding to the ozone amount. Therefore, if it is determined that knocking has occurred, the ignition timing is retarded, and ozone is supplied so that the amount of air containing ozone does not change, so torque fluctuation due to ignition timing retardation is suppressed. However, it is possible to appropriately avoid the occurrence of knocking.

  Note that the order of steps S203 and S205 may be interchanged, and the order of steps S207 and S209 may also be interchanged. It is only necessary that the ignition timing retardation and the ozone supply be performed substantially at the same time.

  By the way, if the ozone supply means 44 cannot supply ozone during the ignition timing retardation control as described above, it is impossible to compensate for the torque decrease due to the ignition timing retardation. In particular, as described above, when the ignition delay amount is further increased from the viewpoint of ozone supply, the torque reduction amount cannot be ignored. Therefore, in the present embodiment, the above-described control for avoiding knocking is terminated in order to suppress the torque drop, that is, the torque fluctuation at this time. However, in general, for the control in such a transition period, the ignition timing is newly calculated and the calculation necessary for executing it, that is, to greatly change the ignition timing, is to calculate other control values. It takes a long time compared to the switching control. That is, when changing the ignition timing from the ignition timing retarded state, a delay of the determination calculation (interrupt calculation) occurs, and the ignition timing is in an over retarded state during the delay. In this case, combustion deteriorates during this period, and torque fluctuations that cannot be ignored, that is, torque fluctuations that cause the vehicle to vibrate enough to be perceived by the driver may occur. Therefore, in order to reduce such torque fluctuation, the amount of intake air is increased at this time so as to compensate for the torque decrease due to the ignition timing retardation. The control will be described below, but the following description is established in the presence of the control described above. Therefore, the following description will be made based on the above description. In the following description, FIGS. 3 and 4 are further used.

  FIG. 3 shows a valve timing diagram of the intake / exhaust valves 26, 34. A black arrow indicates the valve timing (EX) of the exhaust valve 34, and a white arrow indicates the valve timing (IN) of the intake valve 26. In FIG. 3, the ignition timing is also indicated by white stars. However, the solid line in the figure represents the valve timing and ignition timing at that time, and the dotted line represents the valve timing and ignition timing at the previous stage. FIG. 3A shows a valve timing diagram in, for example, a high-load operation, that is, an operation state in which knocking may occur, and FIG. 3B shows the valve timing diagram in FIG. FIG. 3 (c) shows the valve timing diagram when the ignition timing is retarded with the ozone supply from the state of FIG. 3. FIG. 3 (c) shows that the ozone supply cannot be performed while knocking is avoided, so that the intake air amount can be increased. FIG. 3D shows the valve timing diagram when the opening timing of the intake valve 26 is advanced from the state shown in FIG. 3B, and FIG. 3D ends the ignition timing retarding control for avoiding the occurrence of knocking. The valve timing diagram when returning to the original is conceptually shown. FIG. 4 is a conceptual diagram in which air amount (intake air amount + ozone amount), intake valve opening timing advance amount, torque, ignition advance amount, and ozone amount are arranged side by side with respect to time. .

  As shown in FIG. 3 (a), the valve operating mechanism is operated at the valve timing of the intake and exhaust valves 26 and 34, and as shown in the figure, the air-fuel mixture is mixed before compression top dead center, for example, several degrees before compression top dead center. When the occurrence of knocking is detected, the control for delaying the ignition timing is performed in order to avoid the occurrence of knocking as described above. For example, as shown in FIG. 3B, the ignition timing before the compression top dead center represented by the dotted line is ignited after the compression top dead center represented by the solid line, for example, several degrees after the compression top dead center. The time is retarded. As a result, a significant increase in the in-cylinder pressure is avoided, and an increase in the temperature of the air-fuel mixture is also suppressed, making it possible to prevent the occurrence of self-ignition that does not depend on flame propagation.

  When the control is performed as shown in FIG. 3B, the time t0 to the time t1 in FIG. 4 correspond to each other. At this time, the ignition timing is retarded by the ignition retard amount Δθa. In addition, ozone supply for a predetermined amount Fa is performed. By controlling in this way, it becomes possible to avoid the occurrence of knocking without causing torque reduction, that is, torque fluctuation, compared to before the ignition timing is retarded. However, if a failure occurs in the ozone supply means 44 at time t1 in FIG. 4, ozone will not be supplied thereafter. Therefore, the occurrence of knocking can be avoided by continuing to retard the ignition timing. However, if this state is maintained as it is, the torque will decrease. Therefore, in the present invention, control for avoiding the occurrence of knocking is terminated in order to give priority to avoiding such torque fluctuations over avoiding occurrence of knocking.

  In the present embodiment, the failure of the ozone supply unit 44 is determined based on an output signal from the ozone sensor 56. That is, if the ozone concentration obtained based on the output signal from the ozone sensor 56 is equal to or less than a predetermined value, it is determined that there is a failure, and if it exceeds this, it is determined that there is no failure.

  By the way, as described above, the determination calculation of the ignition timing control takes a longer time than the determination calculation of the opening degree of the throttle valve 16, the valve timings of the intake and exhaust valves 26 and 34, the fuel injection amount, etc. The difference is remarkable in the transition period of control switching. Therefore, after a failure occurs in the ozone supply means 44 (time t1), the ignition timing delay correction is terminated and the ignition timing is advanced by an amount corresponding to the ignition delay amount Δθa (time t2). In order to suppress the torque fluctuation based on the delay time Δt conceptually shown in FIG. 4, the intake air amount is increased by changing the valve timing as shown in FIG. In this embodiment, when it is determined that the ozone supply means 44 is out of order, as shown in FIG. 3C, the opening timing of the intake valve 26 is advanced from the opening timing represented by the dotted line to the time represented by the solid line. Sufficient valve overlap. The advancement degree (advance amount) (Δθva in FIG. 4) at this time is obtained in advance by experiments and stored in the ROM. If the intake air amount increases, it is excluded that the valve timing and lift amount of the intake / exhaust valves 26 and 34 are changed in other ways by searching data (not shown) based on the operation state. is not.

  In general, the valve timings of the intake / exhaust valves 26 and 34 are set so as to be away from the knocking limit where the possibility of knocking is high so that knocking does not occur as described above. Therefore, even when the ignition timing is retarded, even if the valve timing is changed and the intake air amount increases to some extent, knocking does not occur due to the increase in the intake air amount.

  Returning to FIG. 3, in the state where the ignition timing is retarded while the intake air amount is increased, the time Δt corresponding to the delay in the ignition timing determination calculation has elapsed, and it is possible to return from the ignition timing retarded state. Then, while returning the opening timing of the intake valve 26, the ignition timing is also returned to the original state, and the state is returned to the state where the ignition timing retarding control or the like for avoiding knocking is not performed (in FIG. 3D). Solid line). This case corresponds to the time t2 in FIG.

  By doing so, it may not be possible to avoid the occurrence of knocking, but for example, an unexpected torque fluctuation as shown by a dotted line in FIG. 4 is prevented. Therefore, it is possible to prevent vibrations or the like felt by the driver or the like from occurring in the vehicle. That is, according to the above control, drivability is not deteriorated.

  As mentioned above, although this invention was demonstrated based on the said embodiment, this does not limit this invention. In the above embodiment, the ozone supply means 44 is provided so as to supply ozone to the intake passage 14, but the present invention is not limited to this. The present invention includes the provision of ozone supply means at any location such as an intake port, an intake manifold, and an intake pipe upstream of the intake port in order to supply ozone into the cylinder 20. For example, ozone may be supplied into the intake air that has already been taken into the combustion chamber 32, or ozone may be supplied into the air-fuel mixture already formed in the combustion chamber 32. That is, the present invention does not exclude not only providing the ozone supply means 44 so as to supply ozone in the intake passage 14 but also supplying ozone directly to the combustion chamber 32.

  Further, the ozone supply means 44 is not limited to the above embodiment, and may be a device that generates and supplies other ozone. For example, a reactor may be provided as an ozone supply means in the intake passage so that air that has passed through the air cleaner passes inside. More specifically, a reaction provided with an insulator case forming a part of the intake passage, a center electrode arranged along the central axis of the case, and a high voltage power source connected to the center electrode by a metal wire It is good also as providing a device in the middle of an intake passage. Then, by controlling the high voltage power source so as to apply a desired high voltage to the center electrode, it is possible to discharge into the air flowing through the intake passage and generate and supply ozone in the intake air.

  Further, in the above embodiment, the ignition delay amount for avoiding the occurrence of knocking is made constant, and the supply amount of ozone supplied at the same time and the opening degree (throttle amount) of the throttle valve 16 are made constant. It is also good. For example, when knocking has not occurred, the angle is advanced by a predetermined angle. When knocking has occurred, the angle is retarded by a predetermined angle, and the engine 10 is operated in a boundary region where knocking occurs or not. An ignition timing may be set. Then, an ozone amount corresponding to such an ignition retardation amount may be derived each time to control the ozone supply. That is, the engine 10 sequentially learns and corrects the ignition timing, outputs an operation signal to the igniter based on the ignition timing obtained in this way, and supplies the ozone supply means 44 to the ozone supply means 44 to execute the same amount of ozone. Also good. Thereby, it is possible to more appropriately suppress the torque fluctuation when the occurrence of knocking is avoided. In this case, the opening degree of the throttle valve 16, that is, the throttle amount is preferably derived and controlled in each case.

  In the above embodiment, ozone is supplied only when the occurrence of knocking is avoided, but the present invention does not exclude supplying ozone at other times. For example, when the engine is started, ozone may be supplied to improve combustion at that time. However, in order to generate and supply ozone, a large amount of electric power is consumed. Therefore, it is preferable to limit the ozone supply time when the ozone supply requirement is high, such as when knocking is avoided as described above.

  Furthermore, in the above embodiment, the failure of the ozone supply means 44 is determined based on the output signal from the ozone sensor 56, but the determination may be made using other means. For example, a failure of the ozone supply unit 44 may be determined from a change in power consumption in the ozone generator 46. Alternatively, the failure of the ozone supply means 44 may be determined based on an output signal from the in-cylinder pressure sensor, that is, the combustion pressure sensor. Specifically, only control for retarding the ignition timing with a minute time difference is performed when preventing the occurrence of knocking. Then, the combustion pressure at this time is detected and stored. Then, in addition to the ignition timing retardation, ozone supply is started with a slight time difference, and the combustion pressure when ozone is supplied is continuously detected. Then, these are compared, and if the combustion pressure when ozone is further supplied is higher than the combustion pressure when only the ignition timing is retarded, it is determined that ozone is properly supplied; Is determined not to be properly supplied. That is, when ozone is supposed to be supplied but no increase in combustion pressure is recognized, it may be determined that the ozone supply means has failed. Alternatively, a torque sensor may be provided, and it may be determined that the ozone supply means is out of order when a decrease in torque is detected in spite of supplying ozone.

  In the above embodiment, the knock sensor is used as the knocking detection means. However, the occurrence of knocking may be detected or estimated by another method. For example, when a predetermined operating state is located in a region with a high load or high rotation, the occurrence of knocking is estimated, and control for preventing knocking may be performed as described above.

  Furthermore, in the above embodiment, a valve mechanism using the intake valve 26 and the exhaust valve 34 as electromagnetically driven valves is used. However, other valve mechanisms such as intake and exhaust valves 26 and 34 having cams and camshafts are used. It does not exclude the valve mechanism. For example, any other mechanism may be used as long as it can change the phase of the operating angle of the intake valve 26 and the exhaust valve 34 so that the intake air amount can be increased. Such devices include known variable valve timing mechanisms and variable valve timing-lift mechanisms. For example, the operating angle of the intake valve 26 or the exhaust valve 34 can be changed by the hydraulic pressure controlled by the ECU 48. For example, a plurality of cams are provided, and the intake valves can be switched by switching the cams. There is one that continuously changes the phase of the operating angle of the valve 26 and the exhaust valve 34. In addition, a variable timing controller is provided on the camshaft rotated by the timing chain, and the hydraulic pressure of the advance chamber and the like in the housing is adjusted so that the phase of the working angle of the intake valve 26 and the exhaust valve 34 is continuously adjusted. There is something to change.

  In the above embodiment, the internal combustion engine to which the present invention is applied is a spark ignition engine of an intake port injection type, but other spark ignition engines, for example, a spark ignition engine of in-cylinder injection type may be used.

  In the above embodiment, the present invention has been described with a certain degree of concreteness, but various modifications and changes can be made to the present invention without departing from the spirit and scope of the invention described in the claims. It must be understood that. That is, the present invention includes modifications and changes that fall within the scope and spirit of the appended claims and their equivalents.

1 is a conceptual diagram of an engine system to which an internal combustion engine control device of an embodiment is applied. FIG. 5 is a diagram conceptually showing a series of control flow for avoiding knocking. FIG. 4 is a valve timing diagram conceptually showing valve timings of intake and exhaust valves before, during and after control for avoiding occurrence of knocking, and also shows ignition timing. FIG. 5 is a conceptual diagram in which air amount (intake air amount + ozone amount), intake valve opening timing advance amount, torque, ignition advance amount, and ozone amount are arranged with respect to time.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Engine 14 Intake passage 16 Throttle valve 18 Surge tank 22 Intake manifold 24 Fuel injection valve 30 Spark plug 32 Combustion chamber 36 Exhaust manifold 38 Exhaust passage 42 Catalytic converter 44 Ozone supply means 46 Ozone generator 50 Discharge passage 54 Knock sensor 56 Ozone sensor

Claims (3)

Knock detection means for detecting or estimating occurrence of knock;
An ignition timing retarding means for retarding the ignition timing when occurrence of knocking is detected or estimated by the knocking detection means;
Ozone supply means for supplying ozone so that ozone is supplied into the cylinder when the ignition timing is retarded by the ignition timing retarding means;
A control device for an internal combustion engine, comprising:   2. The control apparatus for an internal combustion engine according to claim 1, wherein the amount of ozone supplied by the ozone supply means corresponds to an ignition delay amount by the ignition timing delay means. Failure determination means for determining a failure of the ozone supply means;
An intake air amount increasing means for increasing the intake air amount by an intake air amount corresponding to the ozone amount scheduled to be supplied when a failure of the ozone supply means is determined by the failure determination means;
The control device for an internal combustion engine according to claim 1, further comprising:

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