JP2009013895A - Control device for internal combustion engine, control method, program for realizing the method by computer, and recording medium recording the program - Google Patents

Abstract

An object of the present invention is to suppress an influence caused by an erroneous determination of knocking.
When a correlation coefficient K between a vibration waveform detected by a knock sensor and a knock waveform model is larger than K (0) and a knock magnitude N is larger than V (0), an engine ECU 200 (S114). ) If knocking is determined (S116) and noise is not erroneously determined (NO in S118), ignition timing is retarded (S120) and noise is erroneously determined (YES in S118) ) If the advance angle is not (NO in S122), the ignition timing is maintained (S124). If the advance angle is NO (YES in S122), the ignition timing is advanced (YES). S128) is executed.
[Selection] Figure 9

Description

  The present invention relates to control of ignition timing of an internal combustion engine, and more particularly to a technique for appropriately controlling ignition timing in accordance with the degree of erroneous determination of knocking.

  Conventionally, various methods for detecting knocking (knock) occurring in an internal combustion engine have been proposed. For example, there is a technique for determining that knocking has occurred when the intensity of vibration of an internal combustion engine is higher than a threshold value. However, since it is determined that knocking has occurred even if the intensity of vibration due to mechanical noise or the like is higher than a threshold value, there is a possibility that knocking may be erroneously determined. For example, if it is erroneously determined that noise is knocking, the ignition timing is excessively retarded, resulting in problems such as deterioration in fuel consumption, reduction in output, and excessive increase in exhaust temperature. Further, when knocking cannot be detected because it is erroneously determined as noise, there is a problem such as deterioration of engine durability.

  In view of such a problem, Japanese Utility Model Laid-Open No. 5-64470 (Patent Document 1) discloses a knocking control device for an internal combustion engine in which knocking control is not performed by engine vibration other than knocking. This knocking control device compares basic ignition timing setting means for setting basic ignition timing according to engine operating conditions, engine vibration detection means for detecting engine vibration, and a detected value of engine vibration and a predetermined reference value. An internal combustion engine comprising knocking determination means for determining knocking when the former is greater than the latter, and advance / retard angle correction amount setting means for setting an advance / retard angle correction amount of the basic ignition timing in accordance with the presence or absence of knocking A correction amount for stopping the use of the ignition timing advance / deceleration correction amount when it is determined that knocking has occurred in the engine knock control device when the delay direction correction by the advance / retard correction means has continued for a predetermined number of times or more. The use stop means is provided.

According to the knocking control device disclosed in this publication, when it is determined that knocking has occurred in a state where the correction in the retarded direction has continued for a predetermined number of times or more, it is determined that the engine vibration other than knocking is the cause, and the ignition timing is By stopping the use of the angle correction amount, erroneous control due to engine vibration caused by noise other than knocking can be prevented, and the accuracy of control and the performance of the internal combustion engine are improved.
Japanese Utility Model Publication No. 5-64470

  However, in the knocking control device disclosed in the above-mentioned publication, engine vibration other than knocking occurs when it is determined that knocking has occurred when the correction in the retarding direction has continued for a predetermined number of times. However, there is a possibility that knocking is erroneously determined as noise because engine vibration other than knocking is not necessarily generated. In addition, even if it is determined that knocking has occurred before the correction in the retarding direction has continued for a predetermined number of times, engine vibration other than knocking may have occurred. there's a possibility that.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to realize a control device, a control method, and a method for an internal combustion engine that suppress effects caused by erroneous determination of knocking by a computer. Program and a recording medium on which the program is recorded.

  According to a first aspect of the present invention, there is provided a control device for an internal combustion engine, comprising: means for detecting vibration generated in the internal combustion engine; and whether or not vibration corresponding to knocking has occurred in the internal combustion engine based on the detected vibration intensity. A determination means for determining, a control means for controlling the ignition timing of the internal combustion engine based on the determination result, and a degree of erroneous determination of knocking is calculated based on the detected vibration and the ignition timing of the internal combustion engine. And a suppression control means for controlling the internal combustion engine such that an increase in the degree of erroneous determination is suppressed when the calculated degree of erroneous determination increases. An internal combustion engine control method according to a tenth aspect of the invention has a configuration similar to that of the control device for an internal combustion engine according to the first aspect of the invention.

  According to the first invention, the vibration corresponding to knocking tends to converge if the ignition timing is retarded, whereas mechanical noise other than knocking does not converge even if the ignition timing is retarded. Therefore, for example, in a state where the frequency of the detected vibration intensity being equal to or greater than the magnitude corresponding to knocking is increasing in spite of the fact that the ignition timing is retarded to the retard side, There is a high possibility of misjudging noise as knocking. In this case, for example, the internal combustion engine is controlled so as to suppress an increase in the degree of erroneous determination by suppressing the control of the ignition timing to the retard side or increasing the threshold value of the intensity corresponding to knocking. By controlling this, an excessive retardation of the ignition timing is suppressed, so that deterioration in fuel consumption, output reduction, and excessive increase in exhaust temperature can be suppressed. Therefore, it is possible to provide a control device and a control method for an internal combustion engine that suppress the influence caused by the erroneous determination of knocking.

  In the control apparatus for an internal combustion engine according to the second invention, in addition to the configuration of the first invention, the calculation means increases the retard amount of the ignition timing of the internal combustion engine and the detected vibration intensity. Means are included for calculating the degree to which the frequency of increasing the strength corresponding to knocking is increased. An internal combustion engine control method according to an eleventh aspect of the invention has the same configuration as the internal combustion engine control apparatus according to the second aspect of the invention.

  According to the second aspect of the invention, in the state where the retard amount of the ignition timing of the internal combustion engine increases and the frequency at which the detected vibration intensity becomes equal to or greater than the intensity corresponding to knocking increases, noise is erroneously detected as knocking. The possibility of judging is high. Therefore, by calculating the degree of such a state, the degree of erroneous determination can be calculated with high accuracy.

  In the control apparatus for an internal combustion engine according to the third invention, in addition to the configuration of the second invention, the calculating means calculates the amount of change in frequency at which the detected vibration intensity is equal to or greater than the intensity corresponding to knocking. The first change amount calculating means for calculating the change amount of the retard amount of the ignition timing of the internal combustion engine, and the change amount of the frequency and the change amount of the retard angle amount. And the means for calculating so as to increase the degree of erroneous determination. An internal combustion engine control method according to a twelfth aspect of the invention has the same configuration as the control apparatus for an internal combustion engine according to the third aspect of the invention.

  According to the third aspect of the present invention, in the state where the retard amount of the ignition timing of the internal combustion engine increases and the frequency at which the detected vibration intensity becomes equal to or greater than the intensity corresponding to knocking increases, noise is erroneously detected as knocking. The possibility of judging is high. Therefore, the degree of erroneous determination can be calculated with high accuracy by calculating so that the degree of erroneous determination increases as both the amount of change in frequency and the amount of change in retard amount increase.

  In the control apparatus for an internal combustion engine according to the fourth aspect of the invention, in addition to the configuration of the third aspect of the invention, the first change amount calculating means may detect the detected vibration in the predetermined number of ignition cycles of the internal combustion engine. Means for calculating a frequency at which the intensity of the power is equal to or greater than a predetermined intensity corresponding to knocking, and means for calculating a difference between the calculated frequency and the frequency calculated by the previous calculation . An internal combustion engine control method according to a thirteenth aspect of the invention has the same configuration as the internal combustion engine control apparatus according to the fourth aspect of the invention.

  According to the fourth aspect of the invention, in the predetermined number of ignition cycles of the internal combustion engine, the difference between the frequency at which the detected vibration intensity is equal to or higher than the predetermined intensity corresponding to knocking and the previously calculated frequency is calculated. By calculating, it is possible to calculate with high accuracy a state in which the frequency at which the detected vibration intensity is greater than or equal to the intensity corresponding to knocking increases.

  In the control apparatus for an internal combustion engine according to the fifth invention, in addition to the configuration of the third invention, the second change amount calculating means is configured to ignite the internal combustion engine in a predetermined number of ignition cycles of the internal combustion engine. Means for calculating an average value of the timing, and means for calculating a difference between the calculated average value of the ignition timing and the average value of the ignition timing calculated by the previous calculation. An internal combustion engine control method according to a fourteenth aspect of the invention has a configuration similar to that of the control device for an internal combustion engine according to the fifth aspect of the invention.

  According to the fifth invention, the retard amount of the ignition timing of the internal combustion engine is increased by calculating the difference between the average ignition timing in the predetermined number of ignition cycles of the internal combustion engine and the previously calculated average ignition timing. It is possible to calculate the state being performed with high accuracy.

  In the control apparatus for an internal combustion engine according to the sixth invention, in addition to the configuration of any one of the first to fifth inventions, the determination means has a detected vibration intensity equal to or greater than a threshold value of the intensity corresponding to knocking. Means for determining that knocking has occurred in the internal combustion engine. The suppression control means includes means for increasing the strength threshold value corresponding to knocking when the calculated degree of erroneous determination is large. An internal combustion engine control method according to a fifteenth aspect of the invention has the same configuration as the control device for an internal combustion engine according to the sixth aspect of the invention.

  According to the sixth aspect of the invention, the degree of erroneous determination increases the intensity threshold value corresponding to knocking, thereby suppressing an increase in the frequency at which the detected vibration intensity is determined to be vibration corresponding to knocking. can do. That is, an increase in the degree of erroneous determination can be suppressed.

  In the control apparatus for an internal combustion engine according to the seventh aspect of the invention, in addition to the configuration of any one of the first to fifth aspects, the suppression control means can control the ignition timing of the internal combustion engine if the calculated degree of erroneous determination is large. Means for suppressing the control to the retard side are included. An internal combustion engine control method according to a sixteenth aspect of the invention has the same configuration as the control device for an internal combustion engine according to the seventh aspect of the invention.

  According to the seventh invention, by suppressing the control of the ignition timing of the internal combustion engine to the retarded angle side, it is possible to suppress the occurrence of vibrations other than knocking that increase as the retarded angle side is reached. That is, an increase in the degree of erroneous determination can be suppressed.

  In addition to the structure of the seventh invention, the control device for an internal combustion engine according to the eighth invention is configured such that the ignition timing of the internal combustion engine is changed after a predetermined time has elapsed since the control to the retard side is suppressed. Means for controlling the internal combustion engine to be on the advance side is further included. An internal combustion engine control method according to a seventeenth invention has the same configuration as the control device for an internal combustion engine according to the eighth invention.

  According to the eighth invention, the control means controls the internal combustion engine so that the ignition timing of the internal combustion engine becomes an advance side after a predetermined time has elapsed since the control to the retard side is suppressed. . Thereby, an unnecessary retardation amount due to erroneous determination can be eliminated. Therefore, it is possible to suppress an increase in vibration of noise other than knocking, a decrease in output, and a deterioration in fuel consumption.

The control apparatus for an internal combustion engine according to a ninth aspect of the present invention is the control apparatus for the internal combustion engine according to the ninth aspect, wherein the detected vibration intensity in the predetermined number of ignition cycles of the internal combustion engine is predetermined corresponding to knocking. And a means for calculating a frequency that is equal to or higher than the intensity and a means for canceling the suppression of the control to the retard side when the calculated frequency increases. An internal combustion engine control method according to an eighteenth aspect of the invention has the same configuration as the internal combustion engine control apparatus according to the ninth aspect of the invention.

  According to the ninth aspect, vibration corresponding to knocking can be generated by controlling the ignition timing of the internal combustion engine to the advance side. Therefore, when the calculated frequency increases, the control of the ignition timing can be controlled to be retarded according to the occurrence of knocking by stopping the suppression of the retarding control. Therefore, the adverse effect on the engine due to knocking can be reduced.

  A program according to a nineteenth invention is a program for realizing the control method for an internal combustion engine according to any one of the tenth to eighteenth inventions by a computer, and the recording medium according to the twentieth invention is a program according to the tenth to eighteenth invention. A medium having recorded thereon a computer-implemented method for controlling an internal combustion engine according to any one of the inventions.

  According to the nineteenth or twentieth invention, the internal combustion engine control method according to any of the tenth to eighteenth inventions can be realized using a computer (which may be general purpose or dedicated).

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  With reference to FIG. 1, a description will be given of an engine 100 of a vehicle equipped with a control device for an internal combustion engine according to an embodiment of the present invention. The engine 100 is provided with a plurality of cylinders. The control device for an internal combustion engine according to the present embodiment is realized by a program executed by an engine ECU (Electronic Control Unit) 200, for example.

Engine 100 is an internal combustion engine that burns an air-fuel mixture of air sucked from air cleaner 102 and fuel injected from injector 104 by igniting with an ignition plug 106 in a combustion chamber. The ignition timing is the MBT (Minimum advance for Best) that maximizes the output torque.
Torque). However, when knocking occurs, it is retarded or advanced according to the operating state of the engine 100.

  When the air-fuel mixture burns, the piston 108 is pushed down by the combustion pressure, and the crankshaft 110 rotates. The combusted air-fuel mixture (exhaust gas) is purified by the three-way catalyst 112 and then discharged outside the vehicle. The amount of air taken into engine 100 is adjusted by throttle valve 114.

  Engine 100 is controlled by engine ECU 200. The engine ECU 200 includes a knock sensor 300, a water temperature sensor 302, a crank position sensor 306 provided facing the timing rotor 304, a throttle opening sensor 308, a vehicle speed sensor 310, an ignition switch 312, and an air flow meter. 314 is connected.

Knock sensor 300 is provided in a cylinder block of engine 100. Knock sensor 300 is composed of a piezoelectric element. Knock sensor 300 generates a voltage due to vibration of engine 100. The magnitude of the voltage corresponds to the magnitude of the vibration. Knock sensor 300 transmits a signal representing a voltage to engine ECU 200. Water temperature sensor 302 detects the temperature of the cooling water in the water jacket of engine 100 and transmits a signal representing the detection result to engine ECU 200.

  The timing rotor 304 is provided on the crankshaft 110 and rotates together with the crankshaft 110. A plurality of protrusions are provided on the outer periphery of the timing rotor 304 at predetermined intervals. The crank position sensor 306 is provided to face the protrusion of the timing rotor 304. When the timing rotor 304 rotates, the air gap between the protrusion of the timing rotor 304 and the crank position sensor 306 changes, so that the magnetic flux passing through the coil portion of the crank position sensor 306 increases and decreases, and an electromotive force is generated in the coil portion. . Crank position sensor 306 transmits a signal representing the electromotive force to engine ECU 200. Engine ECU 200 detects the crank angle and the rotational speed of crankshaft 110 based on the signal transmitted from crank position sensor 306.

  Throttle opening sensor 308 detects the throttle opening and transmits a signal representing the detection result to engine ECU 200. Vehicle speed sensor 310 detects the number of rotations of a wheel (not shown) and transmits a signal representing the detection result to engine ECU 200. Engine ECU 200 calculates the vehicle speed from the rotational speed of the wheel. Ignition switch 312 is turned on by the driver when engine 100 is started. Air flow meter 314 detects the amount of air taken into engine 100 and transmits a signal representing the detection result to engine ECU 200.

  Engine ECU 200 is operated by electric power supplied from auxiliary battery 320 as a power source. The engine ECU 200 performs arithmetic processing based on signals transmitted from the sensors and the ignition switch 312, a map and a program stored in a ROM (Read Only Memory) 202, so that the engine 100 enters a desired operating state. Control equipment.

  In the present embodiment, engine ECU 200 determines a knock detection gate (from a predetermined first crank angle to a predetermined second crank angle) based on a signal transmitted from knock sensor 300 and a crank angle. ) And a vibration waveform of the engine 100 (hereinafter referred to as a vibration waveform) is detected, and it is determined whether knocking has occurred in the engine 100 based on the detected vibration waveform. The knock detection gate in the present embodiment is from top dead center (0 degree) to 90 degrees in the combustion stroke. The knock detection gate is not limited to this.

  When knocking occurs, vibration of a frequency near the frequency indicated by the solid line in FIG. The frequency of vibration generated due to knocking is not constant and has a predetermined bandwidth. Therefore, in the present embodiment, as shown in FIG. 2, vibrations in the fourth frequency band D including the first frequency band A, the second frequency band B, and the third frequency band C are detected. . Note that CA in FIG. 2 indicates a crank angle. Further, the frequency band of vibration generated due to knocking is not limited to three.

  The engine ECU 200 will be further described with reference to FIG. Engine ECU 200 includes an A / D (analog / digital) conversion unit 400, a bandpass filter 410, and an integration unit 420.

The A / D converter 400 converts the analog signal transmitted from the knock sensor 300 into a digital signal. Bandpass filter 410 passes only the signal of fourth frequency band D among the signals transmitted from knock sensor 300. That is, only the vibration in the fourth frequency band D is extracted from the vibration detected by knock sensor 300 by bandpass filter 410.

  The accumulating unit 420 accumulates the signal selected by the bandpass filter 410, that is, the vibration intensity by 5 degrees in terms of crank angle. Hereinafter, the integrated value is referred to as an integrated value. By calculating the integrated value corresponding to the crank angle, a vibration waveform of the engine 100 is detected as shown in FIG.

  The detected vibration waveform is compared with a knock waveform model stored in ROM 202 of engine ECU 200 as shown in FIG. The knock waveform model is created in advance as a model of a vibration waveform when knocking occurs in engine 100.

  In the knock waveform model, the vibration intensity is expressed as a dimensionless number from 0 to 1, and the vibration intensity does not uniquely correspond to the crank angle. That is, in the knock waveform model of the present embodiment, it is determined that the vibration intensity decreases as the crank angle increases after the peak value of the vibration intensity. The corner is not fixed.

  The knock waveform model in the present embodiment corresponds to the vibration of a predetermined crank angle after the peak value of the intensity of vibration generated by knocking. Note that a knock waveform model corresponding to the vibration after the rise of vibration caused by knocking may be stored.

  The knock waveform model detects the vibration waveform of engine 100 when knocking is forcibly generated by experiments or the like, and is created and stored in advance based on the vibration waveform.

  The knock waveform model is created using the engine 100 (hereinafter referred to as a characteristic center engine) in which the dimensions of the engine 100 and the output value of the knock sensor 300 are the median of the tolerances of the dimensions and the output value of the knock sensor 300. Is done. That is, the knock waveform model is a vibration waveform when knocking is forcibly generated in the characteristic center engine. The method of creating the knock waveform model is not limited to this, and may be created by simulation.

  In the comparison between the detected waveform and the knock waveform model, as shown in FIG. 6, the normalized waveform and the knock waveform model are compared. Here, normalization is to express the intensity of vibration by a dimensionless number from 0 to 1, for example, by dividing each integrated value by the maximum integrated value in the detected vibration waveform. The normalization method is not limited to this.

  In the present embodiment, engine ECU 200 calculates a correlation coefficient K representing the degree to which the normalized vibration waveform is similar to the knock waveform model (representing the deviation between the vibration waveform and the knock waveform model). In the state where the timing when the vibration intensity is maximized in the vibration waveform after normalization and the timing when the vibration intensity is maximum in the knock waveform model are matched, the intensity in the vibration waveform after normalization and the intensity in the knock waveform model The correlation coefficient K is calculated by calculating the absolute value (deviation amount) of each difference for each crank angle (every 5 degrees). The absolute value of the difference between the intensity in the vibration waveform and the intensity in the knock waveform model may be calculated for each crank angle other than 5 degrees.

Here, the absolute value of the difference for each crank angle between the intensity in the normalized vibration waveform and the intensity in the knock waveform model is set to ΔS (I) (I is a natural number). Let S be the sum of the vibration intensity in the knock waveform model for each crank angle, that is, the area of the knock waveform model. The correlation coefficient K is
K = (S−ΣΔS (I)) / S (1)
Is calculated as Here, ΣΔS (I) is the sum of ΔS (I) at the crank angle at which the vibration waveform and the knock waveform model are compared. Further, the method of calculating the correlation coefficient K is not limited to this.

  Further, engine ECU 200 calculates knock magnitude N representing the magnitude of vibration based on the maximum value (peak value) of the integrated value. If the maximum value of the integrated value is P and a value representing the vibration intensity of the engine 100 in a state where the engine 100 is not knocked is BGL (Back Ground Level), the knock intensity N is N = P / BGL. It is calculated by the equation. The BGL is determined in advance based on, for example, simulations or experiments, and is stored in the ROM 202. Further, the calculation method of knock strength N is not limited to this.

  In the present embodiment, engine ECU 200 compares the calculated knock magnitude N with a threshold value corresponding to the knock stored in ROM 202, and further compares the detected waveform with the stored knock waveform model. Whether or not knocking has occurred in engine 100 is determined every ignition cycle.

  Further, when engine knocking is determined, engine ECU 200 controls engine 100 so that the ignition timing of engine 100 becomes the retarded ignition timing. For example, as shown in FIG. 7, the ignition timing is controlled to be the retarded ignition timing in response to frequent occurrence of knocking. Here, in FIG. 7, the horizontal axis indicates the ignition cycle, and the vertical axis indicates the ignition timing, the determination result of the vibration intensity, and the number of times determined to be knocking. As shown in FIG. 7, when the ignition timing is controlled so as to become the retarded ignition timing, the frequency of occurrence of knocking decreases. At this time, the ignition timing is controlled to converge to a substantially constant retardation amount.

  However, in the case where the intensity of mechanical noise other than knocking exceeds the intensity threshold corresponding to knocking and the noise is erroneously determined as knocking, the ignition timing is There are cases where the ignition timing is controlled to be retarded. As shown in FIG. 8, when the mechanical noise other than knocking exceeds the threshold value of the intensity corresponding to knocking, the ignition timing is controlled to the retard side. Mechanical noise other than knocking does not converge even when the ignition timing is controlled to the retard side. In addition, if the amount of retardation increases, the vibration intensity of mechanical noise other than knocking increases, and the frequency of exceeding the intensity threshold corresponding to knocking may increase, and the ignition timing is excessively retarded. There is a possibility of being controlled by the ignition timing.

  Therefore, the present invention is configured so that when the degree of erroneous determination of knocking based on the detected vibration and the ignition timing of the engine 100 increases, the increase in the degree of erroneous determination is suppressed. It is characterized in that the engine 100 is controlled.

  Specifically, engine ECU 200 enters a state in which the amount of retardation of the ignition timing of engine 100 increases and the frequency at which the intensity of vibration detected by knock sensor 300 is equal to or greater than the intensity corresponding to knocking increases. Calculate the degree. That is, engine ECU 200 calculates the amount of change in frequency at which the detected vibration intensity is equal to or greater than the intensity corresponding to knocking. Further, engine ECU 200 calculates the amount of change in the retard amount of the ignition timing of engine 100. Further, engine ECU 200 calculates so that the degree of erroneous determination increases as both the amount of change in frequency and the amount of change in retard amount increase. In the present embodiment, the amount of change in frequency is larger than a predetermined threshold value, and the amount of change in ignition timing is smaller than a predetermined threshold value (that is, the amount of change to the retard side is smaller). Larger), the noise erroneous determination count value is increased by a predetermined value (in this embodiment, “1”).

  Further, engine ECU 200 suppresses the control of the ignition timing of engine 100 to the retard side when the calculated degree of erroneous determination is large (when the noise erroneous determination count value is equal to or greater than a threshold value). Further, engine ECU 200 controls engine 100 such that the ignition timing of engine 100 becomes the advance side after a predetermined time has elapsed since the control to the retard side is suppressed. Then, engine ECU 200 calculates a frequency at which the detected vibration intensity is equal to or higher than a predetermined intensity corresponding to knocking in a predetermined number of ignition cycles of engine 100, and the calculated frequency increases. Then, the control of the retard side control is stopped.

  Referring to FIG. 9, a program executed by engine ECU 200, which is a control device for an internal combustion engine according to the present embodiment, determines whether or not knocking has occurred and controls ignition timing for each ignition cycle. The control structure will be described.

  In step (hereinafter, step is abbreviated as S) 100, engine ECU 200 detects engine speed NE based on the signal transmitted from crank position sensor 306, and based on the signal transmitted from air flow meter 314. Thus, the intake air amount KL is detected.

  In S102, engine ECU 200 detects the intensity of vibration of engine 100 based on the signal transmitted from knock sensor 300. The intensity of vibration is represented by the output voltage value of knock sensor 300. The intensity of vibration may be represented by a value corresponding to the output voltage value of knock sensor 300. The intensity is detected from the top dead center to 90 degrees (90 degrees in crank angle) in the combustion stroke.

  In S104, engine ECU 200 calculates a value (integrated value) obtained by integrating the output voltage value of knock sensor 300 (a value representing the intensity of vibration) every 5 degrees (for 5 degrees) in crank angle. The vibration waveform of the engine 100 is detected by calculating the integrated value.

  In S106, engine ECU 200 calculates the largest integrated value (peak value P) among the integrated values in the vibration waveform of engine 100.

  In S108, engine ECU 200 normalizes the vibration waveform of engine 100. Here, normalization means that the intensity of vibration is expressed by a dimensionless number from 0 to 1 by dividing each integrated value by the calculated peak value.

  In S110, engine ECU 200 calculates correlation coefficient K by matching the crank angle of peak value P with the timing at which the magnitude of vibration is maximized in the knock waveform model. In S112, engine ECU 200 calculates knock magnitude N by dividing peak value P by BGL.

  In S114, engine ECU 200 determines whether or not correlation coefficient K is greater than threshold value K (0) and knock magnitude N is greater than threshold value V (0). In the present embodiment, it is described that it is determined whether or not vibration corresponding to knocking has occurred based on correlation coefficient K and knock magnitude N. However, at least knocking magnitude is supported based on knock magnitude N. What is necessary is just to determine whether the vibration generate | occur | produced. Further, the calculation method of knock intensity N is not particularly limited to the above-described method, and a known technique may be used. If correlation coefficient K is greater than threshold value K (0) and knock magnitude N is greater than threshold value V (0) (YES in S114), the process proceeds to S116. If not (NO in S114), the process proceeds to S126.

  In S116, engine ECU 200 determines that knocking has occurred. In S118, engine ECU 200 determines whether noise is being erroneously determined. “Noise misjudgment” means that machine noise other than knocking is misjudged as knocking. The determination of whether or not noise is being erroneously determined is performed by a determination process (1) separately executed, and details thereof will be described later. For example, engine ECU 200 determines that noise is being erroneously determined when the corresponding flag is ON during erroneous noise determination. If noise is being erroneously determined (YES in S118), the process proceeds to S120. If not (NO in S118), the process proceeds to S122. In S120, engine ECU 200 retards the ignition timing.

  In S122, engine ECU 200 determines whether or not the noise avoidance advance is in progress. “Noise avoidance advance” refers to controlling the ignition timing to the advance side in order to avoid an increase in vibration due to mechanical noise other than knocking due to the control to the retard side of the ignition timing. The determination of whether or not the noise avoidance advance is in progress is performed by a determination process (2) separately executed, and details thereof will be described later. For example, the engine ECU 200 determines that the noise avoidance advance is being performed when the corresponding flag during the noise avoidance advance is on. If the noise avoidance advance is in progress (YES in S122), the process proceeds to S128. If not (NO in S122), the process proceeds to S124. In S124, engine ECU 200 holds the ignition timing.

  In S126, engine ECU 200 determines that knocking has not occurred. In S128, engine ECU 200 advances the ignition timing.

  Next, referring to FIG. 10, determination executed by engine ECU 200 that is the control device for the internal combustion engine according to the present embodiment to determine whether noise is being erroneously determined or knock is being determined. The control structure of the program for process (1) will be described.

  In S200, engine ECU 200 determines whether or not a trigger that is turned on every 10 ignitions (hereinafter referred to as a 10 ignition trigger) is on. For example, engine ECU 200 increments a predetermined count value for each ignition cycle of engine 100, and when the count value reaches a value corresponding to the number of times of ignition of 10, the trigger is triggered in the ignition cycle where the number of times of ignition is tenth. Turn on. Engine ECU 200 may reset the count value to the initial value when the 10 ignition trigger is turned on. If 10 ignition trigger is on (YES in S200), the process proceeds to S202. If not (NO in S200), the process proceeds to S226.

  In S202, engine ECU 200 calculates frequency A. Frequency A is the number of times that a vibration having a knock magnitude N greater than a threshold value has occurred during 10 ignitions (between turning off after 10 ignition triggers are turned on).

  In S204, engine ECU 200 calculates change amount dA of frequency A. The engine ECU 200 calculates the difference A−A ′ between the frequency A calculated in S202 and the frequency A ′ calculated during the previous 10 ignitions as the change amount dA.

  In S206, engine ECU 200 calculates average ignition timing B. The average ignition timing B is an average value of the ignition timing during 10 ignitions (between the time when 10 ignition triggers are turned on and until it is turned on). The engine ECU 200 calculates the average ignition timing B by dividing the sum of the ignition timings during 10 ignitions by the number of ignitions “10”. In the present embodiment, the average ignition timing B is described as a positive value on the advance side and a negative value on the retard side. However, instead of the average ignition timing B, the average ignition timing B is a positive value. A retardation amount may be used.

  In S208, engine ECU 200 calculates change amount dB in average ignition timing B. The engine ECU 200 calculates a difference B-B 'between the average ignition timing B calculated in S206 and the previously calculated average ignition timing B' during 10 ignitions as the change amount dB.

  In S210, engine ECU 200 determines whether or not the noise avoidance advance is in progress. If the noise avoidance advance is in progress (YES in S210), the process proceeds to S222. If not (NO in S210), the process proceeds to S212.

  In S212, engine ECU 200 determines whether or not change amount dA is larger than threshold value A (0) and change amount dB is smaller than threshold value B (0). The threshold values A (0) and B (0) are not particularly limited as long as they are adapted by experiments or the like. If variation dA is greater than threshold A (0) and variation dB is smaller than threshold B (0) (YES in S212), the process proceeds to S214. If not (NO in S212), the process proceeds to S220.

  In S214, engine ECU 200 counts up noise erroneous determination count value Ca. That is, engine ECU 200 adds a predetermined value to noise erroneous determination count value Ca.

  In S216, engine ECU 200 determines whether or not noise erroneous determination count value Ca is equal to or greater than a predetermined threshold value Ca (0). Note that the threshold value Ca (0) is not particularly limited as long as the threshold value Ca (0) is adapted by experiments or the like. If noise erroneous determination count value Ca is equal to or greater than a predetermined threshold value Ca (0) (YES in S216), the process proceeds to S218. If not (NO in S216), the process proceeds to S220.

  In S218, engine ECU 200 determines that mechanical noise other than knocking is erroneously determined as knocking. In S220, engine ECU 200 determines that knocking is normally determined.

  In S222, engine ECU 200 determines whether or not change amount dA is greater than threshold value A (1) and change amount dB is greater than or equal to threshold value B (1). A (1) may be the same value as A (0) or a different value. Further, B (1) may be the same value as B (0) or a different value. If variation dA is greater than threshold A (0) and variation dB is greater than threshold B (0) (YES in S222), the process proceeds to S224. If not (NO in S222), the process proceeds to S218.

  In S224, engine ECU 200 performs a return process to normal knock determination. That is, the erroneous noise determination count value Ca is reset to an initial value (for example, “0”). Furthermore, the retard interruption count value Cb is reset to an initial value (for example, “0”). The details of the retard angle interruption count value Cb will be described later.

  In S226, engine ECU 200 determines whether or not the noise avoidance advance is in progress. If the noise avoidance advance is in progress (YES in S226), the process proceeds to S218. If not (NO in S226), the process proceeds to S216.

  Next, referring to FIG. 11, engine ECU 200, which is the control device for the internal combustion engine according to the present embodiment, executes in order to determine whether the noise avoidance advance is in progress or the delay is being interrupted. The control structure of the determination process (2) program will be described.

  In S300, engine ECU 200 determines whether noise erroneous determination count value Ca is equal to or greater than Ca (1). Ca (1) may be the same value as Ca (0) or may be a different value. If noise erroneous determination count value Ca is equal to or greater than Ca (1) (YES in S300), the process proceeds to S302. Otherwise (NO in S300), this process ends.

  In S302, engine ECU 200 determines whether or not the 10 ignition trigger is turned on after Ca becomes equal to or greater than Ca (1). When the 10 ignition trigger is turned on (YES in S302), the process proceeds to S304. If not (NO in S302), the process proceeds to S308.

  In S304, engine ECU 200 counts up retard delay count value Cb. In other words, engine ECU 200 adds a predetermined value to retard angle interruption count value Cb.

  In S306, engine ECU 200 determines whether or not retard stop count value Cb is equal to or greater than threshold value Cb (0). The threshold value Cb (0) is a predetermined value. If retard stop count value Cb is equal to or greater than a predetermined threshold value Cb (0) (YES in S306), the process proceeds to S308. If not (NO in S306), the process proceeds to S310.

  In S308, engine ECU 200 determines that the angle is being advanced to avoid noise. For example, engine ECU 200 turns on the corresponding flag during the noise avoidance advance. In S310, engine ECU 200 determines that the retardation is being interrupted. For example, the engine ECU 200 may turn on the corresponding flag during the delay angle interruption, or turn off the corresponding flag during the noise avoidance advance angle.

  The operation of engine ECU 200 that is the control device for the internal combustion engine according to the present embodiment based on the above-described structure and flowchart will be described.

  During operation of engine 100, engine speed NE is detected based on a signal transmitted from crank position sensor 306, and intake air amount KL is detected based on a signal transmitted from air flow meter 314. (S100). Further, based on the signal transmitted from knock sensor 300, the intensity of vibration of engine 100 is detected (S102).

  An integrated value is calculated every 5 degrees between the top dead center and 90 degrees in the combustion stroke (S104). Thereby, the vibration waveform of engine 100 as shown in FIG. 4 is detected.

  By detecting the vibration waveform by the integrated value every 5 degrees, it is possible to detect the vibration waveform in which the intensity is suppressed from being finely changed. Therefore, the comparison between the detected vibration waveform and the knock waveform model can be facilitated.

  Based on the calculated integrated value, a peak value P of the integrated value in the vibration waveform of engine 100 is calculated (S106).

The integrated value in the vibration waveform of the engine 100 is divided by the calculated peak value P to normalize the vibration waveform (S108). By normalization, the vibration intensity in the vibration waveform is 0-1
It is expressed as a dimensionless number. Thereby, it is possible to compare the detected vibration waveform with the knock waveform model regardless of the intensity of vibration. Therefore, it is not necessary to store a large number of knock waveform models corresponding to the vibration intensity, and the creation of the knock waveform model can be facilitated.

  The timing at which the vibration intensity is maximized in the normalized vibration waveform and the timing at which the vibration intensity is maximized in the knock waveform model are matched (see FIG. 6), and the correlation coefficient K is calculated in this state. (S110).

  Thereby, the degree of coincidence between the detected vibration waveform and the knock waveform model can be expressed numerically and objectively determined. Further, by comparing the vibration waveform with the knock waveform model, it is possible to analyze whether or not the vibration is during knocking from the vibration behavior such as the vibration attenuation tendency.

  Further, knock magnitude N is calculated by dividing peak value P by BGL (S112). Thereby, it is possible to analyze in more detail whether or not the vibration of engine 100 is a vibration caused by knocking based on the intensity of vibration.

  If correlation coefficient K is equal to or smaller than threshold value K (0), or knock magnitude N is equal to or smaller than threshold value V (0) (NO in S114), it is determined that knocking has not occurred. (S126) The ignition timing is advanced (S128).

  If correlation coefficient K is greater than threshold value K (0) and knock magnitude N is greater than threshold value V (0) (YES in S114), it is determined that knocking has occurred ( S116) If no erroneous noise determination is in progress (NO in S118), the ignition timing is retarded (S120), and the occurrence of knocking is suppressed. In this way, by comparing the knock magnitude N with the threshold value V (0), it is determined whether or not knocking has occurred for each ignition cycle, and the ignition timing is retarded or advanced. .

  Further, if the erroneous noise determination is in progress (S118) and the noise avoidance advance is in progress (YES in S122), the ignition timing is advanced (S128). Further, since the noise is being erroneously determined (S118) and the noise avoidance advance is not in progress (NO in S122), the ignition timing is maintained (S124), so control is performed on both the retard side and the advance side. Not.

  For example, it is assumed that noise vibration other than knocking occurs in engine 100. In FIG. 12, the horizontal axis indicates the ignition cycle, and the vertical axis indicates the ignition timing, the knocking determination result, and the number of determinations. At this time, it is assumed that the corresponding flag during the noise avoidance advance is off. Also, the white point plotted in the graph showing the relationship between the ignition timing and the ignition cycle in FIG. 12 shows the average ignition timing B during 10 ignition cycles, and the graph showing the relationship between the number of determinations and the ignition cycle in FIG. The black dots plotted in FIG. 5 indicate the frequency A during 10 ignition cycles.

  When the 10 ignition trigger is turned on in the ignition cycle Ct (1) (YES in S200), it is determined that knocking occurs between 10 ignitions (between Ct (0) and Ct (1)). The frequency A is calculated (S202). Then, a difference (change amount dA) between the calculated frequency A and the previously calculated frequency A ′ is calculated (S204). Further, an average ignition timing B between 10 ignitions is calculated (S206), and a difference (amount of change dB) between the average ignition timing B and the previously calculated average ignition timing B 'is calculated (S206).

When the advance angle is not noise avoidance (NO in S210), the change amount dA is larger than A (0) (the knocking determination frequency is greatly increased), and the change amount dB is smaller than B (0) (slow When the angular amount increases more (YES in S212), noise erroneous determination count value Ca is counted up (S214).

  Further, the change amount dA is A (0) or less, or the change amount dB is B (0) or more (NO in S212), or the noise erroneous determination count value Ca is the threshold value Ca (0) or more. If not (NO in S216), it is determined that knock determination is being performed (S220). At this time, the flag corresponding to the erroneous noise determination is turned off or kept off. Therefore, while the corresponding flag is OFF during the erroneous noise determination, it is determined that the erroneous noise determination is not being performed (NO in S118), so that the retard control of the ignition timing is continued.

  If the erroneous noise determination count value Ca is equal to or greater than the threshold value C (0) in the ignition cycle Ct (3) (YES in S216), it is determined that the erroneous noise determination is being performed (S218). Therefore, even if correlation coefficient K is greater than threshold value K (0) and knock magnitude N is greater than threshold value V (0) (YES in S114), it is determined that knocking has occurred. (S116) Since the noise is being erroneously determined (YES in S118) and not in the noise avoidance advance (NO in S122), in the ignition cycle from Ct (3) to Ct (4), the retarded angle The control is interrupted and the ignition timing is maintained (S124).

  In ignition cycle Ct (4), noise erroneous determination count value Ca is equal to or greater than C (1) (YES in S300), and then 10 ignition trigger is turned on (YES in S302), 10 ignition trigger Even if is OFF (NO in S302), if the counted delay delay count value Cb is greater than or equal to the threshold value Cb (0) (YES in S304, S306), the noise avoidance advance is in progress And the corresponding flag is turned on during the noise avoidance advance. Therefore, even if knocking is determined (S116) and a noise erroneous determination is being made (YES in S118), since the noise avoidance advance is being made (YES in S122), Ct (4) to Ct (5) In the ignition cycle up to, the ignition timing is controlled to the advance side (S128).

  When the 10 ignition trigger is turned on in the ignition cycle Ct (5) (S200), the frequency A, the change amount dA, the average ignition timing B, and the change amount dB are calculated (S202 to S208), and the noise avoidance advance is in progress. (YES in S210), change dA is greater than A (1) (knocking determination frequency increases greatly), and change dB is greater than or equal to B (1) (advance amount increases). Then, in the ignition cycle from Ct (5) to Ct (6), return processing to normal knock determination is executed (S224). For this reason, the noise erroneous determination count value Ca and the retarded stop count Cb are reset to the initial values. At this time, the corresponding flag during the noise avoidance advance may be turned off.

  As described above, according to the control device for an internal combustion engine according to the present embodiment, the vibration corresponding to knocking tends to converge if the ignition timing is retarded, whereas mechanical noise other than knocking Does not converge even if the ignition timing is retarded. Therefore, for example, in a state where the frequency of the detected vibration intensity being equal to or greater than the magnitude corresponding to knocking is increasing in spite of the fact that the ignition timing is retarded to the retard side, There is a high possibility of misjudging noise as knocking. In this case, by suppressing the ignition timing control to the retarded angle side, the engine is controlled so that an increase in the noise erroneous determination count value Ca is suppressed, and the excessive retard of the ignition timing is suppressed. Therefore, fuel consumption deterioration, output reduction, and excessive increase in exhaust temperature can be suppressed. Therefore, it is possible to provide a control device and a control method for an internal combustion engine that suppress the influence caused by the erroneous determination of knocking.

In addition, when the amount of retard of the ignition timing of the engine increases and the frequency at which the detected vibration intensity exceeds the intensity corresponding to knocking increases, there is a possibility that noise is erroneously determined as knocking. Is expensive. Therefore, by calculating such a state numerically as the noise erroneous determination count value, the degree of erroneous determination can be calculated with high accuracy.

  In addition, the engine ECU controls the ignition timing of the engine so that it becomes the advance side after a predetermined time has elapsed since the control to the retard side is suppressed. Thereby, an unnecessary retardation amount due to erroneous determination can be eliminated. Therefore, it is possible to suppress output reduction and fuel consumption deterioration.

  In the present embodiment, if the engine ECU determines that the noise is being erroneously determined, the engine ignition timing is maintained and the ignition timing is controlled to the retarded side unless the noise avoidance advance is being performed. However, the present invention is not limited to this. For example, the threshold value V (0) of the knock intensity N may be increased. Even if it does in this way, since the increase in the noise erroneous determination count value Ca can be suppressed, an excessive retardation of the ignition timing can be suppressed.

  Furthermore, in the present embodiment, it has been described that the ignition timing is controlled to be advanced after a predetermined time has elapsed since the ignition timing control to the retard side is suppressed. As shown in FIG. 13, the ignition timing control to the retard side may be continuously suppressed. Even in this case, it is possible to suppress the retard of the excessive ignition timing. In addition, you may make it cancel suppression of retardation by the fall of the frequency A, for example.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a schematic configuration diagram showing an engine controlled by an engine ECU which is a control device for an internal combustion engine according to an embodiment of the present invention. It is a figure which shows the frequency band of the vibration which generate | occur | produces with an engine at the time of knocking. It is a control block diagram which shows the engine ECU of FIG. It is a figure which shows the vibration waveform of an engine. It is a figure which shows the knock waveform model memorize | stored in ROM of engine ECU. It is the figure which compared the vibration waveform and the knock waveform model. FIG. 6 is a diagram (part 1) illustrating a change in ignition timing and determination frequency with respect to a change in ignition cycle. FIG. 6 is a diagram (part 2) showing a change in ignition timing and determination frequency with respect to a change in ignition cycle. It is a flowchart which shows the control structure of the program which engine ECU which is a control apparatus of the internal combustion engine which concerns on this Embodiment performs. It is a flowchart which shows the control structure of the program of the determination process (1) which engine ECU which is a control apparatus of the internal combustion engine which concerns on this Embodiment performs. It is a flowchart which shows the control structure of the program of the determination process (2) which engine ECU which is a control apparatus of the internal combustion engine which concerns on this Embodiment performs. FIG. 6 is a diagram (part 3) illustrating a change in ignition timing and determination frequency with respect to a change in ignition cycle. FIG. 6 is a diagram (part 4) illustrating a change in ignition timing and determination frequency with respect to a change in ignition cycle.

Explanation of symbols

100 Engine, 102 Air Cleaner, 104 Injector, 106 Spark Plug, 108 Piston, 110 Crankshaft, 112 Three-way Catalyst, 114 Throttle Valve, 200 Engine ECU, 202 ROM, 300 Knock Sensor, 302
Water temperature sensor, 304 timing rotor, 306 crank position sensor, 308
Throttle opening sensor, 310 vehicle speed sensor, 312 ignition switch, 314 air flow meter, 320 auxiliary battery, 400 A / D converter, 410 band-pass filter, 420 accumulator.

Claims (20)

Means for detecting vibrations occurring in the internal combustion engine;
Determination means for determining whether vibration corresponding to knocking has occurred in the internal combustion engine based on the detected vibration intensity;
Control means for controlling the ignition timing of the internal combustion engine based on a determination result;
Calculation means for calculating the degree of erroneous determination of knocking based on the detected vibration and the ignition timing of the internal combustion engine;
A control apparatus for an internal combustion engine, comprising: suppression control means for controlling the internal combustion engine such that an increase in the degree of erroneous determination is suppressed when the calculated degree of erroneous determination increases.   The calculating means calculates the degree to which the retard amount of the ignition timing of the internal combustion engine increases and the frequency at which the detected vibration intensity becomes equal to or greater than the intensity corresponding to the knocking increases. The control apparatus for an internal combustion engine according to claim 1, comprising: The calculating means includes
First change amount calculating means for calculating a change amount of the frequency at which the detected vibration intensity is equal to or greater than the intensity corresponding to the knocking;
A second change amount calculating means for calculating a change amount of the retard amount of the ignition timing of the internal combustion engine;
The control device for an internal combustion engine according to claim 2, further comprising means for calculating so that the degree of erroneous determination increases when both the change amount of the frequency and the change amount of the retardation amount increase. The first change amount calculation means includes:
Means for calculating a frequency at which the intensity of the detected vibration is greater than or equal to a predetermined intensity corresponding to knocking in a predetermined number of ignition cycles of the internal combustion engine;
The control device for an internal combustion engine according to claim 3, comprising means for calculating a difference between the calculated frequency and a frequency calculated by a previous calculation. The second change amount calculating means includes:
Means for calculating an average value of the ignition timing of the internal combustion engine in a predetermined number of ignition cycles of the internal combustion engine;
The control apparatus for an internal combustion engine according to claim 3, further comprising means for calculating a difference between the calculated average value of the ignition timing and the average value of the ignition timing calculated by the previous calculation. The determination means includes means for determining that knocking has occurred in the internal combustion engine when the detected vibration intensity is greater than or equal to a threshold value of intensity corresponding to knocking,
The internal combustion engine according to any one of claims 1 to 5, wherein the suppression control means includes means for increasing a threshold value of an intensity corresponding to the knocking when the calculated degree of erroneous determination is large. Control device.   The said suppression control means contains a means for suppressing the control to the retard side of the ignition timing of the said internal combustion engine, if the calculated degree of erroneous determination is large. Control device for internal combustion engine.   The control device is configured to control the internal combustion engine so that an ignition timing of the internal combustion engine becomes an advance side after a predetermined time has elapsed since the control to the retard side is suppressed. The control device for an internal combustion engine according to claim 7, further comprising: The controller is
Means for calculating a frequency at which the intensity of the detected vibration is greater than or equal to a predetermined intensity corresponding to knocking in a predetermined number of ignition cycles of the internal combustion engine;
The control device for an internal combustion engine according to claim 8, further comprising means for canceling the suppression of the control to the retard side when the calculated frequency increases. Detecting vibrations occurring in the internal combustion engine;
A determination step of determining whether or not vibration corresponding to knocking has occurred in the internal combustion engine based on the detected vibration intensity;
A control step for controlling the ignition timing of the internal combustion engine based on a determination result;
A calculation step for calculating a degree of erroneous determination of the knocking based on the detected vibration and the ignition timing of the internal combustion engine;
A control method for an internal combustion engine, comprising: a suppression control step for controlling the internal combustion engine such that an increase in the degree of erroneous determination is suppressed when the calculated degree of erroneous determination increases.   The calculating step calculates the degree to which the amount of retardation of the ignition timing of the internal combustion engine increases and the frequency at which the detected vibration intensity becomes greater than or equal to the intensity corresponding to the knocking increases. The method for controlling an internal combustion engine according to claim 10, comprising: The calculating step includes:
A first change amount calculating step of calculating a change amount of a frequency at which the detected vibration intensity is equal to or higher than the intensity corresponding to the knocking;
A second change amount calculating step for calculating a change amount of the retard amount of the ignition timing of the internal combustion engine;
The control method for an internal combustion engine according to claim 11, further comprising a step of calculating so that the degree of erroneous determination increases when both the change amount of the frequency and the change amount of the retard amount increase. The first change amount calculating step includes:
Calculating a frequency at which the intensity of the detected vibration is equal to or greater than a predetermined intensity corresponding to knocking in a predetermined number of ignition cycles of the internal combustion engine;
The method for controlling an internal combustion engine according to claim 12, comprising calculating a difference between the calculated frequency and a frequency calculated by a previous calculation. The second change amount calculating step includes:
Calculating an average value of the ignition timing of the internal combustion engine in a predetermined number of ignition cycles of the internal combustion engine;
The method for controlling an internal combustion engine according to claim 12, comprising calculating a difference between the calculated average value of the ignition timing and the average value of the ignition timing calculated by the previous calculation. The determination step includes a step of determining that knocking has occurred in the internal combustion engine when the detected vibration intensity is equal to or greater than a threshold value of intensity corresponding to knocking,
The control of the internal combustion engine according to any one of claims 10 to 14, wherein the suppression control step includes a step of increasing an intensity threshold value corresponding to the knocking when the calculated degree of erroneous determination is large. Method.   The internal combustion engine according to any one of claims 10 to 14, wherein the suppression control step includes a step of suppressing control of the ignition timing of the internal combustion engine to the retard side when the calculated degree of erroneous determination is large. How to control the engine. The control method further includes a step of controlling the internal combustion engine so that an ignition timing of the internal combustion engine becomes an advance side after a predetermined time has elapsed since the control to the retard side is suppressed. The method for controlling an internal combustion engine according to claim 16, further comprising: The control method is:
Calculating a frequency at which the intensity of the detected vibration is equal to or greater than a predetermined intensity corresponding to knocking in a predetermined number of ignition cycles of the internal combustion engine;
The method of controlling an internal combustion engine according to claim 17, further comprising a step of canceling the suppression of the control to the retard side when the calculated frequency increases.   A program for realizing the control method for an internal combustion engine according to any one of claims 10 to 18 by a computer.   A recording medium recording a program for realizing the control method for an internal combustion engine according to any one of claims 10 to 18 by a computer.

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