JP4559977B2 - Ignition timing control device for internal combustion engine - Google Patents

Description

  The present invention relates to an ignition timing control device for an internal combustion engine, and more particularly to a technique for controlling the ignition timing according to the presence or absence of knocking.

  Conventionally, various methods for determining the presence or absence of knocking (knocking) have been proposed. For example, there is a technique for determining the occurrence of knocking based on whether or not the intensity of vibration detected from an internal combustion engine is greater than a knock determination value. A knock control device for an internal combustion engine described in Japanese Patent Laying-Open No. 2003-21032 (Patent Document 1) includes a knock sensor for detecting knocking of the internal combustion engine, and statistical processing for statistically processing an output signal detected by the knock sensor. A first temporary determination unit that determines the occurrence of knocking based on the processing result of the statistical processing unit, and a second temporary determination unit that determines the occurrence of knocking based on the waveform shape of the output signal detected by the knock sensor A determination unit, and a final knock determination unit that finally determines the occurrence of knocking based on the results of the knock temporary determination by the first temporary determination unit and the knock temporary determination by the second temporary determination unit. The final knock determination unit determines that knocking has finally occurred when both the first temporary determination unit and the second temporary determination unit determine that knocking has occurred. The first provisional determination unit compares the maximum value of the output signal detected by the knock sensor with the knock determination level (knock determination value) calculated based on the processing result of the statistical processing unit, thereby preventing knocking. It is determined whether it has occurred. The knock determination value is corrected to a value that can appropriately control the ignition timing based on the maximum value of the output signal of a predetermined number of cycles detected by the knock sensor.

According to the knock control device described in this publication, only when it is determined that knocking has occurred in each temporary determination using the knock temporary determination by the statistical processing program and the knock temporary determination by the waveform shape program, Finally, it is determined that knocking has occurred. Thereby, in the knock determination using only the statistical processing program and the waveform shape program, it is possible to accurately determine the occurrence of knocking even for an output signal in which knocking is erroneously detected.
JP 200321032 A

  However, in the knock control device described in Japanese Patent Application Laid-Open No. 2003-21032, when the rotational speed of the internal combustion engine is low, it takes time to detect the maximum value of the output signal for the predetermined number of cycles. Therefore, it takes a long time to correct the determination value once. As a result, it takes time to determine whether knocking has occurred accurately or not, and to obtain a knock determination value that can appropriately control the ignition timing. For this reason, it takes a long time to correct the determination value so that the ignition timing can be appropriately controlled. As a result, there has been a problem that the ignition delay when knocking occurs and the ignition advance when knocking does not occur may not be performed properly.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide an ignition timing control device for an internal combustion engine that can appropriately control the ignition timing.

  An ignition timing control device for an internal combustion engine according to a first aspect of the present invention includes a knock strength calculation means for calculating a knock strength related to the strength of vibration caused by knocking based on the strength of vibration generated in the internal combustion engine, and the knock strength And means for controlling the ignition timing of the internal combustion engine based on the result of comparing the determination value and the determination value, and a detection means for detecting an intensity value relating to the intensity of vibration generated in the internal combustion engine in a plurality of ignition cycles. And determining means for determining the occurrence frequency of knocking based on the intensity value, and determining means for determining the determination value based on the occurrence frequency of knocking and the rotational speed of the internal combustion engine.

  According to the first invention, based on the intensity of vibration generated in the internal combustion engine, the knock intensity related to the intensity of vibration caused by knocking is calculated, and based on the result of comparing the knock intensity with a predetermined determination value. The ignition timing of the internal combustion engine is controlled. For example, when the knock magnitude is larger than the determination value, it is determined that knocking has occurred, and the ignition timing is retarded. If the knock magnitude is smaller than the determination value, it is determined that knocking has not occurred, and the ignition timing is advanced. By the way, even if the same vibration occurs in the internal combustion engine due to, for example, variation or deterioration of the output value of the knock sensor, the intensity detected by the knock sensor may change, and the calculated knock intensity may change. In this case, the ignition timing appropriately controlled in the initial state of the internal combustion engine may be inappropriate. Therefore, for example, when it can be said that the frequency of occurrence of knocking is high, it is necessary to determine the determination value according to the state of vibration generated in the internal combustion engine so that the frequency at which the retard control of the ignition timing is performed increases. . Therefore, intensity values relating to the intensity of vibration generated in the internal combustion engine are detected in a plurality of ignition cycles. The occurrence frequency of knocking is determined based on the detected plurality of intensity values. Here, when the rotational speed of the internal combustion engine is low, it takes time to detect the quantity of intensity values necessary for determining the occurrence frequency of knocking. Therefore, it takes time to determine the frequency of occurrence of knocking, and the time required to determine one determination value becomes longer. As a result, it takes a long time to determine the determination value so that the ignition timing can be appropriately controlled. Therefore, the determination value is determined based on the occurrence frequency of knocking and the rotational speed of the internal combustion engine. For example, when it is determined that the occurrence frequency of knocking is high, the determination value is determined to be small. Therefore, the ignition timing retarding control can be performed more. Conversely, when it is determined that the occurrence frequency of knocking is low, the determination value is determined to be large. Therefore, more advance control of the ignition timing can be performed. In addition, when the rotational speed of the internal combustion engine is low, the determination value is determined so as to be closer to a value that can appropriately control the ignition timing, compared to when the rotational speed is high. Therefore, it is possible to suppress an increase in the time taken for the determination value to be a value that can appropriately control the ignition timing. Thus, the determination value can be determined based on the occurrence frequency of knocking and the rotational speed of the internal combustion engine, and the ignition timing can be appropriately controlled. As a result, an ignition timing control device for an internal combustion engine that can appropriately control the ignition timing can be provided.

  An ignition timing control device for an internal combustion engine according to a second aspect of the invention includes, in addition to the configuration of the first invention, an ignition timing control device for correcting a predetermined determination value based on the occurrence frequency of knocking. It further includes correction means and setting means for setting the correction amount of the determination value based on the rotational speed of the internal combustion engine. The determination unit includes a unit for determining the determination value by correcting the predetermined determination value by the correction unit.

  According to the second invention, the predetermined determination value is corrected based on the occurrence frequency of knocking. For example, the determination value is corrected so that the determination value decreases when it is determined that the occurrence frequency of knocking is high, and the determination value is increased when it is determined that the occurrence frequency of knocking is low. The correction amount of the determination value is set based on the rotational speed of the internal combustion engine. For example, when the rotational speed of the internal combustion engine is low, the correction amount of the determination value is set larger than when the rotational speed is high. For this reason, it is possible to suppress an increase in the time required to properly control the ignition timing.

  The ignition timing control apparatus for an internal combustion engine according to a third aspect of the present invention, in addition to the configuration of the second aspect of the present invention, is characterized in that the setting means sets the correction amount of the determination value as compared with the case where the internal combustion engine is low when the rotational speed is low. Means for setting larger.

  According to the third invention, the correction amount of the determination value is set larger when the rotational speed of the internal combustion engine is low than when it is high. When the rotational speed of the internal combustion engine is low, it takes time to detect the quantity of intensity values necessary for determining the occurrence frequency of knocking. Therefore, it takes time to determine the frequency of occurrence of knocking, and the time required to correct one determination value becomes longer. As a result, it takes a long time to correct the determination value so that the ignition timing can be appropriately controlled. Therefore, when the rotational speed of the internal combustion engine is low, the correction amount of the determination value is set larger than when the rotational speed is high. For this reason, it is possible to suppress an increase in the time required to properly control the ignition timing.

  An ignition timing control device for an internal combustion engine according to a fourth aspect of the present invention is that, in addition to the configuration of the second or third aspect, the ignition timing control device is such that the correction amount of the determination value is smaller than a predetermined value. And further includes means for prohibiting.

  According to the fourth invention, it is prohibited that the correction amount of the determination value becomes smaller than a predetermined value. For this reason, it is possible to prevent the correction amount of the determination value from becoming too small and increasing the time required to properly control the ignition timing.

  An ignition timing control device for an internal combustion engine according to a fifth aspect of the present invention is based on the number of revolutions of the internal combustion engine, in addition to the configuration of any one of the first to fourth aspects, and the determination means determines the occurrence frequency of knocking. It further includes quantity setting means for setting the quantity of intensity values to be used.

  According to the fifth invention, the quantity of intensity values used for determining the occurrence frequency of knocking is set based on the rotational speed of the internal combustion engine. When the rotational speed of the internal combustion engine is low, it takes time to detect the quantity of intensity values necessary for determining the occurrence frequency of knocking. Therefore, it takes time to determine the frequency of occurrence of knocking, and the time required to determine one determination value becomes longer. As a result, it takes a long time to determine the determination value so that the ignition timing can be appropriately controlled. Therefore, the number of intensity values used by the determining means for determining the occurrence frequency of knocking is set based on the rotational speed of the internal combustion engine. For example, the number of intensity values used for determining the occurrence frequency of knocking is set to be smaller when the rotational speed of the internal combustion engine is low than when it is high. For this reason, it is possible to suppress an increase in the time required to properly control the ignition timing.

  An ignition timing control device for an internal combustion engine according to a sixth aspect of the present invention includes a knock strength calculating means for calculating a knock strength related to the strength of vibration caused by knocking based on the strength of vibration generated in the internal combustion engine, and the knock strength And means for controlling the ignition timing of the internal combustion engine based on the result of comparing the determination value and the determination value, and a detection means for detecting an intensity value relating to the intensity of vibration generated in the internal combustion engine in a plurality of ignition cycles. A determination means for determining the occurrence frequency of knocking based on the intensity value, a determination means for determining a determination value based on the occurrence frequency of knocking, and a determination based on the rotational speed of the internal combustion engine Quantity setting means for setting the quantity of intensity values used by the means for determining the occurrence frequency of knocking.

  According to the sixth aspect of the invention, the knock magnitude related to the magnitude of vibration caused by knocking is calculated based on the magnitude of vibration generated in the internal combustion engine, and based on the result of comparing the knock magnitude and the determination value, The ignition timing is controlled. For example, when the knock magnitude is larger than the determination value, it is determined that knocking has occurred, and the ignition timing is retarded. When the knock intensity is smaller than a predetermined determination value, it is determined that knocking has not occurred, and the ignition timing is advanced. By the way, even if the same vibration occurs in the internal combustion engine due to, for example, variation or deterioration of the output value of the knock sensor, the intensity detected by the knock sensor may change, and the calculated knock intensity may change. In this case, the ignition timing appropriately controlled in the initial state of the internal combustion engine may be inappropriate. Therefore, for example, when it can be said that the frequency of occurrence of knocking is high, it is necessary to determine the determination value according to the state of vibration generated in the internal combustion engine so that the frequency at which the retard control of the ignition timing is performed increases. . Therefore, intensity values relating to the intensity of vibration generated in the internal combustion engine are detected in a plurality of ignition cycles. The occurrence frequency of knocking is determined based on a plurality of detected intensity values, and the determination value is determined based on the occurrence frequency of knocking. For example, when it is determined that the occurrence frequency of knocking is high, the determination value is corrected to be small. Therefore, the ignition timing retarding control can be performed more. On the other hand, when it is determined that the occurrence frequency of knocking is low, the determination value is corrected so as to increase. Therefore, more advance control of the ignition timing can be performed. Thereby, the determination value can be determined based on the occurrence frequency of knocking, and the ignition timing can be controlled appropriately. By the way, if the rotational speed of the internal combustion engine is low, it takes time to detect the quantity of intensity values necessary for determining the occurrence frequency of knocking. Therefore, it takes time to determine the frequency of occurrence of knocking, and the time required to correct one determination value becomes longer. As a result, it takes a long time to determine the determination value so that the ignition timing can be appropriately controlled. Therefore, the number of intensity values used by the determining means for determining the occurrence frequency of knocking is set based on the rotational speed of the internal combustion engine. For example, the number of intensity values used for determining the occurrence frequency of knocking is set to be smaller when the rotational speed of the internal combustion engine is low than when it is high. For this reason, it is possible to suppress an increase in the time required to properly control the ignition timing. As a result, an ignition timing control device for an internal combustion engine that can appropriately control the ignition timing can be provided.

  In the ignition timing control device for an internal combustion engine according to the seventh invention, in addition to the configuration of the fifth or sixth invention, the quantity setting means uses the quantity of the intensity value used for determining the occurrence frequency of knocking as the internal combustion engine. When the number of rotations is low, it includes means for setting the number of rotations to be smaller than when the number of rotations is high.

  According to the seventh invention, the number of strength values used for determining the occurrence frequency of knocking is set to be smaller when the rotational speed of the internal combustion engine is low than when it is high. When the rotational speed of the internal combustion engine is low, it takes time to detect the quantity of intensity values necessary for determining the occurrence frequency of knocking. Therefore, it takes time to determine the frequency of occurrence of knocking, and the time required to determine one determination value becomes longer. As a result, it takes a long time to determine the determination value so that the ignition timing can be appropriately controlled. Therefore, the number of intensity values used for determining the occurrence frequency of knocking is set to be smaller when the rotational speed of the internal combustion engine is low than when it is high. For this reason, it is possible to suppress an increase in the time required to properly control the ignition timing.

  An ignition timing control device for an internal combustion engine according to an eighth aspect of the invention includes a predetermined number of intensity values used for determining the occurrence frequency of knocking in addition to the configuration of any of the fifth to seventh aspects of the invention. Further included is a means for inhibiting less.

  According to the eighth aspect, the quantity of strength values used for determining the occurrence frequency of knocking is prohibited from becoming smaller than a predetermined quantity. Thereby, it can be suppressed that the number of intensity values used for determining the occurrence frequency of knocking becomes too small, and the determination accuracy of the occurrence frequency of knocking is deteriorated. A determination value is determined based on such a determination result of the occurrence frequency of knocking. Thereby, ignition timing can be controlled appropriately.

  An ignition timing control device for an internal combustion engine according to a ninth aspect of the present invention includes a predetermined number of intensity values used for determining the occurrence frequency of knocking in addition to the configuration of any of the fifth to eighth aspects of the invention. It further includes means for prohibiting the increase.

  According to the ninth aspect, the number of strength values used for determining the occurrence frequency of knocking is prohibited from being larger than a predetermined number. Thereby, it can be suppressed that the number of intensity values used for determining the occurrence frequency of knocking becomes too large, and the time taken to determine the occurrence frequency of knocking becomes too long. For this reason, it is possible to suppress an increase in the time required to properly control the ignition timing.

  An ignition timing control device for an internal combustion engine according to a tenth aspect of the invention is for detecting a waveform of vibration generated in the internal combustion engine at a predetermined interval in addition to the configuration of any of the first to ninth aspects of the invention. A predetermined condition among a plurality of intensity values based on a result of comparing the detected waveform and the stored waveform with the means, the waveform for storing the reference waveform of the internal combustion engine, and the detected waveform Means for extracting an intensity value satisfying. The determination means includes means for determining the occurrence frequency of knocking based on the extracted intensity value.

  According to the tenth invention, a waveform of vibration generated in the internal combustion engine at a predetermined interval is detected, and the detected waveform is compared with a waveform stored as a waveform of vibration caused by knocking, for example. Further, an intensity value related to the intensity of vibration generated in the internal combustion engine is detected in a plurality of ignition cycles, and an intensity value satisfying a predetermined condition among the detected intensity values is stored as a detected waveform and stored. The extracted waveform is extracted based on the result of comparison. Thereby, intensity values other than those can be extracted without extracting the intensity values in the ignition cycle in which the same waveform as the waveform of the vibration caused by the vibration of the noise component or a waveform close thereto is detected. That is, it is possible to remove the vibration intensity value resulting from the vibration of the noise component. The occurrence frequency of knocking is determined based on such an intensity value. A determination value is determined based on the determination result. Accordingly, it is possible to appropriately determine the determination value and appropriately control the ignition timing based on the vibration state in the past ignition cycle in which the influence of the noise component is suppressed.

  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, an engine 100 of a vehicle equipped with an ignition timing control device according to an embodiment of the present invention will be described. The ignition timing control apparatus 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 controlled to be MBT (Minimum advance for Best Torque) that maximizes the output torque, but is retarded or advanced according to the operating state of the engine 100 such as when knocking occurs. Or

  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 clamp position sensor 306 increases or 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 performs arithmetic processing based on signals transmitted from each sensor and ignition switch 312, a map and a program stored in memory 202, and controls equipment so that engine 100 is in a desired operating state. .

  In the present embodiment, engine ECU 200 determines a predetermined knock detection gate (a predetermined second crank angle from a predetermined first crank angle based on a signal and a crank angle transmitted from knock sensor 300). The vibration waveform of the engine 100 (hereinafter referred to as a vibration waveform) is detected in the period up to this point), and whether or not knocking has occurred in the engine 100 is determined 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, vibrations included in the first frequency band A, the second frequency band B, and the third frequency band C are detected as shown in FIG. Note that CA in FIG. 2 indicates a crank angle. Note that the frequency band of vibrations 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) converter 400, a bandpass filter (1) 410, a bandpass filter (2) 420, a bandpass filter (3) 430, and an integrating unit 450. .

  The A / D converter 400 converts the analog signal transmitted from the knock sensor 300 into a digital signal. Bandpass filter (1) 410 passes only the signal of first frequency band A among the signals transmitted from knock sensor 300. That is, only the vibration in the first frequency band A is extracted from the vibration detected by knock sensor 300 by bandpass filter (1) 410.

  Bandpass filter (2) 420 passes only the signal of second frequency band B among the signals transmitted from knock sensor 300. That is, only the vibration in the second frequency band B is extracted from the vibration detected by knock sensor 300 by bandpass filter (2) 420.

  Bandpass filter (3) 430 passes only signals in third frequency band C among signals transmitted from knock sensor 300. That is, only the vibration in the third frequency band C is extracted from the vibration detected by knock sensor 300 by bandpass filter (3) 430.

  The integrating unit 450 integrates the signals selected by the bandpass filter (1) 410 to the bandpass filter (3) 430, that is, the vibration intensity by 5 degrees in terms of crank angle. Hereinafter, the integrated value is referred to as an integrated value. The integrated value is calculated for each frequency band. By calculating the integrated value, a vibration waveform in each frequency band is detected.

  Further, the calculated integrated values of the first frequency band A to the third frequency band C are added corresponding to the crank angle. That is, the vibration waveforms in the first frequency band A to the third frequency band C are synthesized.

  Thereby, as shown in FIG. 4, the vibration waveform of engine 100 is detected. That is, the combined waveform of first frequency band A to third frequency band C is used as the vibration waveform of engine 100.

  The detected vibration waveform is compared with a knock waveform model stored in memory 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, after the peak value of the vibration intensity, it is determined that the vibration intensity decreases as the crank angle increases. The corner is not fixed.

  The knock waveform model in the present embodiment corresponds to vibrations after the peak value of the vibration intensity 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 value of the integrated value in the detected vibration waveform. The normalization method is not limited to this.

  In the present embodiment, engine ECU 200 calculates correlation coefficient K, which is a value related to the deviation between the normalized vibration waveform and knock waveform model. The deviation between the normalized vibration waveform and the knock waveform model in the state where the timing when the vibration intensity becomes maximum in the normalized vibration waveform and the timing when the vibration intensity becomes maximum in the knock waveform model are matched. By calculating the absolute value (deviation amount) for each crank angle (every 5 degrees), the correlation coefficient K is calculated.

  The absolute value of the deviation between the normalized vibration waveform and knock waveform model for each crank angle is ΔS (I) (I is a natural number), and the value obtained by integrating the vibration intensity in the knock waveform model with the crank angle (knock waveform model) If S is the area, the correlation coefficient K is calculated by the equation K = (S−ΣΔS (I)) / S. Here, ΣΔS (I) is the total sum of ΔS (I) from the top dead center to 90 degrees. In the present embodiment, correlation coefficient K is calculated as a larger value as the shape of the vibration waveform is closer to the shape of the knock waveform model. Therefore, when the vibration waveform includes a vibration waveform due to a factor other than knocking, the correlation coefficient K is calculated to be small. Note that the method of calculating the correlation coefficient K is not limited to this.

  Further, engine ECU 200 calculates knock magnitude N based on the maximum value (peak value) of the integrated values. 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. BGL is stored in the memory 202. The method for calculating knock magnitude N is not limited to this.

  In the present embodiment, engine ECU 200 compares calculated knock magnitude N with determination value V (KX) stored in memory 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.

  As shown in FIG. 7, the determination value V (KX) is stored as a map using the engine speed NE and the intake air amount KL as parameters.

  As the initial value of the determination value V (KX), a value determined in advance through experiments or the like is used. However, the detected intensity can change even when the same vibration occurs in engine 100 due to variations or deterioration in the output value of knock sensor 300. In this case, it is necessary to correct the determination value V (KX) and determine whether or not knocking has occurred using the determination value V (KX) corresponding to the actually detected intensity.

  Therefore, in the present embodiment, the relationship between the intensity value LOG (V), which is a value obtained by logarithmically converting the intensity V, and the frequency (also referred to as the number of times or probability) at which each intensity value LOG (V) is detected is shown. Based on the frequency distribution, knock determination level V (KD) is calculated.

  An intensity value LOG (V) is calculated for each region using the engine speed NE and the intake air amount KL as parameters. The intensity V used for calculating the intensity value LOG (V) is an intensity peak value (peak value of integrated value every 5 degrees) between predetermined crank angles. Based on the calculated intensity LOG (V), a median value V (50) is calculated that accumulates the frequency of the intensity value LOG (V) from the minimum value to 50%. In addition, a standard deviation σ at the intensity value LOG (V) equal to or lower than the median value V (50) is calculated. For example, in the present embodiment, median value V (50) and standard deviation σ approximated to median value and standard deviation calculated based on a plurality of (for example, 200 cycles) intensity values LOG (V) are as follows: It is calculated for each ignition cycle by the calculation method.

  When the intensity value LOG (V) detected this time is larger than the median value V (50) calculated last time, a value obtained by adding a predetermined value C (1) to the median value V (50) calculated last time Is calculated as the median value V (50) of this time. Conversely, when the intensity value LOG (V) detected this time is smaller than the median value V (50) calculated last time, a predetermined value C (2) ( For example, a value obtained by subtracting C (2) is the same value as C (1) is calculated as the median value V (50) of this time.

  The intensity value LOG (V) detected this time is smaller than the median value V (50) calculated last time, and the value obtained by subtracting the standard deviation σ calculated last time from the median value V (50) calculated last time. Is larger, the value obtained by subtracting a value obtained by doubling a predetermined value C (3) from the previously calculated standard deviation σ is calculated as the current standard deviation σ. Conversely, when the intensity value LOG (V) detected this time is larger than the median value V (50) calculated last time, or the standard deviation σ calculated last time from the median value V (50) calculated last time is used. When the value is smaller than the subtracted value, a value obtained by adding a predetermined value C (4) (for example, C (4) is the same value as C (3)) to the previously calculated standard deviation σ is the current standard deviation. Calculated as σ. In addition, the calculation method of median value V (50) and standard deviation (sigma) is not limited to this. The initial value of median value V (50) and standard deviation σ may be a preset value or “0”.

  Knock determination level V (KD) is calculated using median value V (50) and standard deviation σ. As shown in FIG. 8, the value obtained by adding the product of coefficient U (1) (U (1) is a constant, for example, U (1) = 3) and standard deviation σ to median value V (50) is knocked. The determination level is V (KD). The method for calculating knock determination level V (KD) is not limited to this. The frequency of the intensity value LOG (V) greater than the knock determination level V (KD) is determined as the frequency of occurrence of knocking, and the determination value V (KX) is corrected based on the frequency of occurrence of knocking.

  The coefficient U (1) is a coefficient obtained from data or knowledge obtained through experiments or the like. The magnitude value LOG (V) larger than the knock determination level V (KD) when U (1) = 3 substantially matches the magnitude value LOG (V) in the ignition cycle in which knocking actually occurs. A value other than “3” may be used for the coefficient U (1).

  In the frequency distribution of the intensity value LOG (V), if knocking does not occur in the engine 100, a normal distribution is obtained as shown in FIG. 9, and the maximum value V (MAX) of the intensity value LOG (V) and the knock determination level are obtained. V (KD) matches. On the other hand, when knocking occurs, the detected intensity V increases, and when a large intensity value LOG (V) is calculated, as shown in FIG. 10, the maximum value V is greater than the knock determination level V (KD). (MAX) increases.

  Further, when the frequency of occurrence of knocking increases, the maximum value V (MAX) further increases as shown in FIG. At this time, the median value V (50) and the standard deviation σ in the frequency distribution increase with the maximum value V (MAX). Therefore, knock determination level V (KD) increases.

  An intensity value LOG (V) smaller than knock determination level V (KD) is not determined to be an intensity value LOG (V) in a cycle in which knocking has occurred. Therefore, if knock determination level V (KD) increases, knocking is correspondingly increased. Even if this occurs, the frequency at which it is determined that knocking has not occurred increases.

  Therefore, in the present embodiment, as shown in FIG. 12, the intensity value LOG (V) larger than the threshold value V (1) is used by using the intensity value LOG (V) in the region surrounded by the broken line. The median value V (50) and the standard deviation σ are calculated by excluding. FIG. 12 is a diagram in which the calculated intensity value LOG (V) is plotted for each correlation coefficient K in the cycle in which the intensity value LOG (V) was obtained.

  The threshold value V (1) is the median of the frequency distribution of the intensity value LOG (V), the standard deviation and the coefficient U (2) (U (2) is a constant in the intensity value LOG (V) below the median value. For example, it is a value obtained by adding the product of U (2) = 3).

  By extracting only the intensity value LOG (V) smaller than the threshold value V (1) and calculating the median value V (50) and the standard deviation σ, the median value V (50) and the standard deviation σ are excessive. It becomes a stable value. Thereby, knock determination level V (KD) can be suppressed from becoming excessive. Therefore, even if knocking has occurred, it is possible to suppress an increase in the frequency at which it is determined that knocking has not occurred.

  The method of extracting the intensity value LOG (V) used for calculating the median value V (50) and the standard deviation σ is not limited to this. For example, as shown in FIG. 13, among the intensity values LOG (V) smaller than the aforementioned threshold value V (1), the correlation coefficient K is calculated in the ignition cycle larger than the threshold value K (1). The intensity value LOG (V) may be extracted.

  By extracting an intensity value LOG (V) in which the correlation coefficient K is larger than the threshold value K (1), the intensity in the ignition cycle in which the same waveform as that of the vibration caused by the vibration of the noise component or a waveform close thereto is detected The intensity values LOG (V) other than these can be extracted without extracting the values. That is, it is possible to remove the vibration intensity value LOG (V) caused by the vibration of the noise component. By calculating median value V (50) and standard deviation σ based on such intensity value LOG (V), knock determination level V (KD) is calculated. Therefore, the occurrence frequency of knocking can be determined based on the vibration state in the past ignition cycle in which the influence of the noise component is suppressed.

  Referring to FIG. 14, a program executed by engine ECU 200 that is an ignition timing control device according to the present embodiment to determine whether or not knocking has occurred and control the 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 integrated value is calculated for each vibration in the first frequency band A to the third frequency band C. Further, the integrated values of first frequency band A to third frequency band C are added corresponding to the crank angle, and the vibration waveform of engine 100 is detected.

  In S106, engine ECU 200 calculates the largest integrated value (peak value P) among the integrated values in the combined waveform (vibration waveform of engine 100) of first frequency band A to third frequency band C.

  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, which is a value related to the deviation between the normalized vibration waveform and knock waveform model. In S112, engine ECU 200 calculates knock magnitude N.

  In S114, engine ECU 200 determines whether or not correlation coefficient K is larger than a predetermined value and knock magnitude N is larger than determination value V (KX). If correlation coefficient K is greater than a predetermined value and knock magnitude N is greater than determination value V (KX) (YES in S114), the process proceeds to S116. If not (NO in S114), the process proceeds to S120.

  In S116, engine ECU 200 determines that knocking has occurred in engine 100. In S118, engine ECU 200 retards the ignition timing. In S120, engine ECU 200 determines that knocking has not occurred in engine 100. In S122, engine ECU 200 advances the ignition timing.

  Referring to FIG. 15, engine ECU 200 that is the ignition timing control device according to the present embodiment sets the correction amount of determination value V (KX) and executes it to correct determination value V (KX). The control structure of the program will be described.

  In S200, engine ECU 200 calculates intensity value LOG (V) from intensity V detected based on the signal transmitted from knock sensor 300. Here, the intensity V is a peak value between predetermined crank angles (peak value of integrated value every 5 degrees).

  In S202, engine ECU 200 determines whether intensity value LOG (V) is smaller than threshold value V (1) described above. If intensity value LOG (V) is smaller than threshold value V (1) described above (YES in S202), the process proceeds to S204. If not (NO in S202), the process returns to S200.

  In S204, engine ECU 200 calculates median value V (50) and standard deviation σ for extracted intensity value LOG (V). Median value V (50) and standard deviation σ may be calculated every time intensity values LOG (V) for M (M is a natural number, for example, M = 200) cycles are extracted.

  In S206, engine ECU 200 calculates knock determination level V (KD) based on median value V (50) and standard deviation σ.

  In S208, engine ECU 200 counts the ratio of intensity value LOG (V) larger than knock determination level V (KD) in extracted intensity value LOG (V) as knock occupation ratio KC.

  In S210, engine ECU 200 determines whether or not intensity values LOG (V) of N (1) (N (1) is a natural number, for example, N (1) = 150) cycles or more have been extracted. If intensity values LOG (V) equal to or greater than N (1) cycles have been extracted (YES in S210), the process proceeds to S212. If not (NO in S210), the process returns to S200.

  In S212, engine ECU 200 determines whether the number of revolutions of engine 100 is a low rotation region, a medium rotation region, or a high rotation region. When the current rotational speed of engine 100 is smaller than a predetermined rotational speed R (1), engine ECU 200 has a low rotational speed range and is larger than a predetermined rotational speed R (1). When the rotational speed R (2) (R (2)> R (1)) is smaller than the medium rotational speed range, and when the rotational speed is higher than the predetermined rotational speed R (2), Judge each. It should be noted that the rotational speed of engine 100 may be the current rotational speed, or may be the average rotational speed over the elapsed time from when correction value V (KX) was corrected last time. If it is determined that it is the low rotation region (low in S212), the process proceeds to S214. If it is determined that the region is the middle rotation region (middle in S212), the process proceeds to S216. If it is determined that the region is a high rotation region (high in S212), the process proceeds to S218.

  In S214, engine ECU 200 sets correction amount H of determination value V (KX) to be large. The correction amount H (1) of the determination value V (KX) after the setting is a predetermined time A, and a time elapsed after the correction of the previous determination value V (KX) (correction is performed). In the case where the engine 100 is not started, the time elapsed from the start of the engine 100 is B, and the correction value (initial value of the correction value) of the determination value V (KX) before setting is H (0). It is calculated by an equation represented by (B / A) × H (0). The predetermined time A is the time taken to calculate the intensity value LOG (V) for N (1) cycles at the predetermined rotation speed R (1). The method for setting the correction amount H of the determination value V (KX) is not limited to this. Further, the predetermined time A is not limited to this.

  In S216, engine ECU 200 determines whether or not a predetermined time A has elapsed since the previous determination value V (KX) was corrected. If predetermined time A has elapsed (YES in S216), the process proceeds to S220. If not (NO in S216), the process returns to S200.

  In S218, engine ECU 200 has extracted an intensity value LOG (V) of N (2) (N (2) is a natural number greater than N (1), for example, N (2) = 200) cycles or more. Determine whether or not. If intensity values LOG (V) of N (2) cycles or more have been extracted (YES in S218), the process proceeds to S220. If not (NO in S218), the process returns to S200.

  In S220, engine ECU 200 determines whether knock occupancy KC is larger than threshold value KC (0) or not. If knock occupancy KC is larger than threshold value KC (0) (YES in S220), the process proceeds to S222. If not (NO in S220), the process proceeds to S224.

  In S222, engine ECU 200 decreases determination value V (KX). In S224, engine ECU 200 increases determination value V (KX). In S226, the engine ECU starts counting the timer.

  The operation of engine ECU 200 that is the ignition timing control device 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).

  Between the top dead center and 90 degrees in the combustion stroke, an integrated value every 5 degrees is calculated for each vibration in the first frequency band A to the third frequency band C (S104). The calculated integrated values of the first frequency band A to the third frequency band C are added corresponding to the crank angle, and the vibration waveform of the 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 suppress detection of a vibration waveform having a complicated shape in which the vibration intensity changes finely. 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 combined waveform (vibration waveform of engine 100) of first frequency band A to third frequency band C 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 intensity of vibration in the vibration waveform is represented by a dimensionless number from 0 to 1. 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). In this state, the normalized vibration waveform and knock An absolute value ΔS (I) of deviation for each crank angle from the waveform model is calculated. The correlation coefficient K is calculated by K = (S−ΣΔS (I)) / S based on the sum ΣΔS (I) of ΔS (I) and the value S obtained by integrating the vibration intensity with the crank angle in the knock waveform model. (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 greater than a predetermined value and knock magnitude N is greater than determination value V (KX) (YES in S114), it is determined that knocking has occurred (S116), and the ignition timing is The angle is retarded (S118). Thereby, occurrence of knocking is suppressed. If correlation coefficient K is greater than a predetermined value and knock magnitude N is not greater than determination value V (KX) (NO in S114), it is determined that knocking has not occurred (S120). ), The ignition timing is advanced (S122). In this manner, by comparing the knock magnitude N with the determination value V (KX), it is determined whether or not knocking has occurred for each ignition cycle, and the ignition timing is retarded or advanced. .

  By the way, even if the same vibration occurs in the engine 100 due to variations or deterioration in the output value of the knock sensor 300, the detected intensity can change. In this case, it is necessary to correct the determination value V (KX) and determine whether or not knocking has occurred using the determination value V (KX) corresponding to the actually detected intensity. Thus, in order to correct the determination value V (KX), it is necessary to determine the occurrence frequency of knocking at the actually detected intensity.

  Therefore, in engine ECU 200 that is the ignition timing control device according to the present embodiment, intensity value LOG (V) is calculated (S200). If calculated intensity value LOG (V) is smaller than threshold value V (1) described above (YES in S202), median value V (50) and standard deviation σ are calculated (S204). Based on such median value V (50) and standard deviation σ, knock determination level V (KD) is calculated (S206). Therefore, it can be suppressed that knock determination level V (KD) becomes excessive. The ratio of the intensity value LOG (V) larger than the knock determination level V (KD) is counted as the knock occupancy KC (S208). Thereby, the knocking occurrence frequency at the actually detected intensity can be obtained as the knock occupancy KC.

  By the way, when the quantity of intensity values LOG (V) used for calculating median value V (50) and standard deviation σ is small, the accuracy of median value V (50) and standard deviation σ is not sufficiently secured. It is conceivable that the accuracy of knock occupancy KC will deteriorate.

  Accordingly, when the intensity value LOG (V) used for calculating the median value V (50) and the standard deviation σ is N (1) cycles or more, the intensity value LOG (V) is not extracted. (NO in S210), the process from calculation of intensity value LOG (V) (S200) is repeated until intensity values LOG (V) of N (1) cycles or more are extracted. That is, the number of intensity values LOG (V) used for calculating median value V (50) and standard deviation σ is prohibited to be less than N (1) cycles. For example, as shown in FIG. 16, N (1) is a value obtained experimentally in advance by the minimum number of ignitions in which the standard deviation σ in the intensity value LOG (V) converges to the ideal standard deviation. As a result, the accuracy of median value V (50) and standard deviation σ can be ensured to a minimum, and deterioration of the accuracy of knock occupancy KC can be suppressed.

  By the way, as shown in FIG. 17, the time taken to extract the intensity values LOG (V) for N (1) cycles is in a substantially inversely proportional relationship with the rotational speed of the engine 100. Therefore, when the rotational speed of engine 100 is low, it takes time to extract intensity values LOG (V) for N (1) cycles. Accordingly, it takes time to correct a determination value V (KX) described later once. Therefore, it takes a long time to correct the determination value V (KX) and make the ignition timing appropriately controllable.

  Therefore, when it is determined that the rotation speed of engine 100 is in the low rotation range (low in S212), correction amount H of determination value V (KX) is set to be large (S214). As shown in FIG. 18, the correction amount H is increased as the rotational speed of the engine 100 is smaller than the predetermined rotational speed R (1). For this reason, it is possible to suppress an increase in the time required to properly control the ignition timing. At this time, as shown in FIG. 19, the intensity value LOG (V) of N (1) cycles is extracted in the low rotation region. Therefore, as described above, the accuracy of median value V (50) and standard deviation σ can be ensured at a minimum, and deterioration of the accuracy of knock occupancy KC can be suppressed.

  When it is determined that the rotation speed of engine 100 is the medium rotation region or the high rotation region (medium and high in S212), correction amount H remains at initial value H (0). Therefore, the correction amount H of the determination value V (KX) does not become smaller than the initial value H (0), and it is suppressed that the time taken to make the ignition timing appropriately controllable is increased.

  If the rotational speed of engine 100 is greater than a predetermined rotational speed R (1), the rotational speed of engine 100 is determined to be in the middle rotational speed range (middle in S212). Therefore, it is considered that the time T (1) when the intensity values LOG (V) for N (1) cycles are extracted is shorter than the predetermined time A. In such a case, it is desirable to increase the accuracy of the standard deviation σ by increasing the number of extracted intensity values LOG (V) by more than N (1) cycles. Therefore, when it is determined that engine speed is in the middle rotation range (middle in S220), if predetermined time A has not elapsed (NO in S216), intensity value LOG (V) The process from the calculation (S200) is repeated. Therefore, in the middle rotation region, the accuracy of the knock occupancy KC is reduced by increasing the extracted intensity value LOG (V) by N (1) cycles to further improve the accuracy of the standard deviation σ. Can be improved.

  When the rotational speed of the engine 100 is high, many intensity values LOG (V) can be extracted in a short time. Therefore, when the number of revolutions of engine 100 is determined to be in the high revolution range (high in S212), when the intensity value LOG (V) for N (2) cycles is extracted (YES in S218), A determination value V (KX) to be described later is corrected. N (2) is a value obtained by experimentally preliminarily obtaining an ignition number sufficient for the standard deviation σ in the intensity value LOG (V) to converge to the ideal standard deviation. Therefore, in the high rotation region, the accuracy of the standard deviation σ can be sufficiently improved at an early stage. Thereby, it can be suppressed that the number of strength values LOG (V) used for the determination of the knock occupancy KC becomes too large and the time required for the determination of the knock occupancy KC becomes too long.

  When correction amount H of determination value V (KX) is changed in the low rotation region (S214), when a predetermined time A has elapsed in the medium rotation region (YES in S216), and high When intensity values LOG (V) for N (2) cycles are extracted in the rotation region (YES in S218), it is determined whether knock occupancy KC is larger than threshold value KC (0). (S220). When knock occupancy KC is larger than threshold value KC (0) (YES in S220), determination value V (KX) is reduced so that the frequency of ignition timing retard control (S118) is increased. (S222). If knock occupancy KC is smaller than threshold value KC (0) (NO in S220), determination value V (KX) is increased so that the frequency of ignition timing advance control (S122) is increased. (S224). Accordingly, it is possible to appropriately correct the determination value in the knocking determination for each ignition cycle and appropriately control the ignition timing.

  As described above, according to engine ECU 200 that is the ignition timing control device according to the present embodiment, when the engine speed is low, the correction amount of determination value V (KX) is set to be large. Therefore, even when it takes time to correct the determination value V (KX) once, the correction of the determination value V (KX) can make the ignition value closer to the determination value in a state where the ignition timing can be appropriately controlled. it can. For this reason, it is possible to suppress an increase in the time required to properly control the ignition timing. Further, when the engine speed is low, the number of intensity values LOG (V) used for determining the occurrence frequency of knocking is set to the minimum number of ignitions that can ensure the minimum determination accuracy of the occurrence frequency of knocking. . Thereby, the determination of the occurrence frequency of knocking can be performed at an early stage, and the time required for correcting the determination value V (KX) once can be shortened. For this reason, it is possible to suppress an increase in the time required to properly control the ignition timing. As a result, an ignition timing control device for an internal combustion engine that can appropriately control the ignition timing can be provided.

  As shown in FIG. 20, when the strength of vibration due to noise is large, the difference between the maximum value of the integrated value at the time of knocking and the maximum value of the integrated value due to noise is small. May be difficult to distinguish. Therefore, instead of the peak value P of the integrated value, as shown in FIG. 21, the knock intensity is calculated using a total sum of the integrated values in the vibration waveform (a value obtained by integrating all output voltage values of the knock sensor 300 in the knock detection gate). N may be calculated. That is, the knock magnitude N may be calculated by dividing the total sum of the integrated values in the vibration waveform by BGL.

  As shown in FIG. 21, since the generation period of vibration due to noise is shorter than the generation period of vibration due to knocking, the total sum of the integrated values can be greatly different between knocking and noise. Therefore, by calculating the knock intensity N based on the total sum of the integrated values, the difference between the knock intensity N calculated at the time of knocking and the knock intensity N calculated by noise can be increased. Thereby, the vibration caused by knocking and the vibration caused by noise can be clearly distinguished.

  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.

It is a schematic block diagram which shows the engine controlled by engine ECU which is the ignition timing control apparatus which concerns on embodiment of this 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 memory of engine ECU. It is the figure which compared the vibration waveform and the knock waveform model. It is a figure which shows the map of the determination value V (KX) memorize | stored in memory of engine ECU. It is a figure (the 1) which shows frequency distribution of intensity value LOG (V). FIG. 6 is a second diagram illustrating a frequency distribution of intensity values LOG (V). FIG. 10 is a third diagram illustrating a frequency distribution of intensity values LOG (V). It is FIG. (4) which shows frequency distribution of intensity value LOG (V). It is FIG. (1) which shows intensity value LOG (V) used in order to create frequency distribution of intensity value LOG (V). It is FIG. (2) which shows intensity value LOG (V) used in order to create frequency distribution of intensity value LOG (V). 4 is a flowchart (No. 1) showing a control structure of a program executed by the engine ECU of FIG. 4 is a flowchart (No. 2) showing a control structure of a program executed by the engine ECU of FIG. It is a figure which shows the relationship between the number of intensity | strength values LOG (V), and a standard deviation. It is a figure which shows the relationship between the rotation speed of an engine, and the time from which intensity value LOG (V) is extracted. It is a figure which shows the relationship between the rotation speed of an engine, and the corrected amount of determination value V (KX). It is a figure which shows the relationship between the rotation speed of an engine, and the number of intensity | strength values LOG (V) extracted. It is the figure (the 1) which shows the integration value at the time of knocking, and the integration value by noise. It is the figure (the 2) which shows the integrated value at the time of knocking, and the integrated value by noise.

Explanation of symbols

  100 engine, 104 injector, 106 spark plug, 110 crankshaft, 116 intake valve, 118 exhaust valve, 120 pump, 200 engine ECU, 300 knock sensor, 302 water temperature sensor, 304 timing rotor, 306 crank position sensor, 308 throttle opening Sensor, 314 Air flow meter.

Claims (9)

An ignition timing control device for an internal combustion engine,
Knock intensity calculating means for calculating knock intensity related to the intensity of vibration caused by knocking based on the intensity of vibration generated in the internal combustion engine;
Control means for controlling the ignition timing of the internal combustion engine based on the result of comparing the knock magnitude and the determination value;
Detecting means for detecting an intensity value relating to the intensity of vibration generated in the internal combustion engine in a plurality of ignition cycles;
Determination means for determining the occurrence frequency of knocking based on the intensity value;
Determining means for determining the determination value based on the occurrence frequency of knocking and the rotational speed of the internal combustion engine ;
An ignition timing control device for an internal combustion engine, comprising: quantity setting means for setting the quantity of intensity values used by the determination means for determining the occurrence frequency of knocking based on the rotational speed of the internal combustion engine. The ignition timing control device includes:
Correction means for correcting a predetermined determination value based on the occurrence frequency of knocking;
Setting means for setting a correction amount of the determination value based on the rotational speed of the internal combustion engine;
The ignition timing control device for an internal combustion engine according to claim 1, wherein the determining means includes means for determining the determination value by correcting the predetermined determination value by the correcting means.   The ignition timing control for an internal combustion engine according to claim 2, wherein the setting means includes means for setting the correction amount of the determination value larger when the rotational speed of the internal combustion engine is low than when the rotational speed is high. apparatus.   The ignition timing control device for an internal combustion engine according to claim 2 or 3, wherein the ignition timing control device further includes means for prohibiting the correction amount of the determination value from becoming smaller than a predetermined value. An ignition timing control device for an internal combustion engine,
Knock intensity calculating means for calculating knock intensity related to the intensity of vibration caused by knocking based on the intensity of vibration generated in the internal combustion engine;
Control means for controlling the ignition timing of the internal combustion engine based on the result of comparing the knock magnitude and the determination value;
Detecting means for detecting an intensity value relating to the intensity of vibration generated in the internal combustion engine in a plurality of ignition cycles;
Determination means for determining the occurrence frequency of knocking based on the intensity value;
Determining means for determining the determination value based on the occurrence frequency of knocking;
An ignition timing control device for an internal combustion engine, comprising: quantity setting means for setting the quantity of intensity values used by the determination means for determining the occurrence frequency of knocking based on the rotational speed of the internal combustion engine. The quantity setting means includes means for setting the quantity of intensity values used for determining the occurrence frequency of knocking to be smaller when the rotational speed of the internal combustion engine is low than when it is high. Item 6. The ignition timing control device for an internal combustion engine according to Item 1 or 5 . The ignition timing control device, the quantity of the intensity value used for the determination of the frequency of occurrence of knocking, further comprising means for prohibiting be less than the quantity determined in advance, according to any one of claims 1 to 6, Ignition timing control device for internal combustion engine. The ignition timing control device, the quantity of the intensity value used for the determination of the frequency of occurrence of knocking, further comprising means for prohibiting to become more than the quantity determined in advance, according to any one of claims 1 to 7 Ignition timing control device for internal combustion engine. The ignition timing control device includes:
Means for detecting a waveform of vibration generated in the internal combustion engine at a predetermined interval;
Means for storing a waveform serving as a reference for vibration of the internal combustion engine;
Means for extracting an intensity value satisfying a predetermined condition from among the plurality of intensity values based on a result of comparing the detected waveform and the stored waveform;
The ignition timing control device for an internal combustion engine according to any one of claims 1 to 8 , wherein the determination means includes means for determining the occurrence frequency of knocking based on the extracted intensity value.

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