JP4976814B2 - 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. In the first provisional determination unit, whether or not knocking has occurred is determined by comparing the maximum value of the output signal detected by the knock sensor with the knock determination level calculated based on the processing result of the statistical processing unit. Is determined. The knock determination value is corrected to a value obtained by subtracting the set value ΔV from the knock determination value, or a value obtained by adding the product of the value A greater than “1” and the set value ΔV to the knock determination level, based on the occurrence frequency of knocking. Is done.

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

  By the way, in an internal combustion engine, the frequency of occurrence of knocking varies depending on the operating state. For example, knocking is likely to occur in a high rotation / high load region, but knocking is unlikely to occur in a low rotation / low load region. Therefore, when the knock determination level (determination value) is corrected according to the frequency of occurrence of knocking as in the knock control device described in Japanese Patent Application Laid-Open No. 2003-21032, the operating state (output rotational speed and load ( It is conceivable to correct for each region classified according to the intake air amount)) or for each operating state. However, the internal combustion engine is not always operated in all regions (operating states). For example, it can be said that the high rotation and high load region has fewer opportunities to be operated than the medium rotation and middle load region. Therefore, it is not always possible to obtain a sufficient opportunity to correct the determination value in all regions or operating states. In this case, in a region where the determination value is rarely corrected or in an operating state, when the determination value is erroneously corrected by erroneous determination of the occurrence frequency of knocking, an opportunity to return (correct) the determination value to the correct determination value. Less is. Therefore, it is considered that the reliability of the determination value is low. In this case, there is a possibility that the ignition delay when knocking occurs or the ignition advance when knocking does not occur cannot be performed appropriately.

  The present invention has been made to solve the above-described problems, and an object of the present invention 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 is based on the intensity of vibration generated in the internal combustion engine, and determines the knock intensity related to the intensity of vibration caused by knocking as the operating state of the internal combustion engine (output speed and load (Intake air amount) etc.) based on the result of comparing the knock intensity calculating means for calculating for each of the plurality of areas classified according to (the intake air amount), the knock intensity and the determination value determined for each of the plurality of areas The control means for controlling the ignition timing of the internal combustion engine; the correction means for correcting the determination value based on the occurrence frequency of knocking for each of the plurality of areas; and at least one of the plurality of areas. Setting means for setting determination values in other areas so as to have values corresponding to the determination values in the reference area as one area.

  According to the first invention, based on the intensity of vibration generated in the internal combustion engine, the knock intensity relating to the intensity of vibration caused by knocking is calculated for each of a plurality of regions divided according to the operating state of the internal combustion engine. The ignition timing of the internal combustion engine is controlled based on the result of comparing the knock magnitude with the determination value determined for each region. For example, if the knock intensity is greater than a predetermined 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 correct the determination value in accordance with the state of vibration generated in the internal combustion engine so that the frequency of ignition timing retard control is increased. . Therefore, the determination value is corrected for each region based on the occurrence frequency of knocking. For example, when the occurrence frequency of knocking is higher than a predetermined frequency, the determination value is corrected to be small. Therefore, the ignition timing retarding control can be performed more. On the contrary, when the occurrence frequency of knocking is lower than a predetermined frequency, 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 corrected based on the occurrence frequency of knocking, and the ignition timing can be controlled appropriately. However, it is not always possible to obtain sufficient opportunities to correct the determination value in all regions. For example, it is rare to operate an internal combustion engine in a low rotation high load region, a high rotation low load region, or the like. Further, the opportunity for operating the internal combustion engine in the low rotation / low load region and the high rotation / high load region is less than the opportunity for operating the internal combustion engine in the middle rotation / intermediate load region. In areas where there are few opportunities to drive, there are fewer opportunities to correct the judgment value. For this reason, it is considered that the determination value in the region where the driving opportunity is small has a large influence when corrected erroneously and has low reliability. Therefore, the determination value in the other region is set so as to be a value corresponding to the determination value in the reference region which is at least one of the plurality of regions. As a result, if a region having a large opportunity for correction is selected as the reference region, a determination value in a region having a small opportunity for correction can be associated with a determination value in a region having a large opportunity for correction. For this reason, even in a region where there are few opportunities for correction, a judgment value corresponding to the frequency of knocking occurring in the internal combustion engine can be obtained, although this region is not. Based on such a determination value, the ignition timing is retarded or advanced. 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 apparatus for an internal combustion engine according to the second invention, in addition to the configuration of the first invention, the setting means includes a range in which the determination value changes within a range including a reference value corresponding to the determination value in the reference region. By limiting to, a means for setting a determination value in another region so as to become a value corresponding to the determination value in the reference region is included.

  According to the second invention, the range in which the determination value changes is limited to a range including a reference value determined according to the determination value in the reference region. Thereby, it can suppress that the judgment value in the area | region where there is little opportunity to correct | amend becomes large or too small. Based on the result of comparison between the determination value and the knock magnitude, the ignition timing is advanced by being retarded. Therefore, it is possible to appropriately control the ignition timing.

  In the ignition timing control device for an internal combustion engine according to the third invention, in addition to the configuration of the second invention, the plurality of regions are divided according to at least one of the output rotational speed and the load of the internal combustion engine. The The reference value is a value that increases in a region where at least one of the output rotational speed and the load of the internal combustion engine is high.

  According to the third invention, the range in which the determination value changes is limited to a range including a larger reference value in a region where at least one of the output rotation speed and the load of the internal combustion engine is higher. As a result, a relatively large determination value can be obtained in a region where the output rotational speed and the load are large. For this reason, even in the case where knocking has not occurred, a state in which the knock strength is higher than the judgment value frequently occurs in a high rotation region or a high load region where vibration with a relatively large strength can occur, and ignition is performed more than necessary. It is possible to prevent the timing from being delayed.

  In the ignition timing control device for an internal combustion engine according to the fourth invention, in addition to the configuration of the second invention, the plurality of regions are divided according to at least one of the output rotational speed and the load of the internal combustion engine. The The width of the range in which the judgment value changes is larger in the region where the reference value is higher in at least one of the output speed of the internal combustion engine and the load.

  According to the fourth invention, the determination value is changed (corrected) in a range in which at least one of the output rotational speed and the load of the internal combustion engine has a larger width as the region is higher. As a result, the determination value can be changed more in the region where the output rotational speed and the load are larger. For this reason, if the determination value is set to a large value, the knock strength is higher than the determination value in a high rotation region or a high load region where vibration of a relatively large intensity can occur even when knocking has not occurred. Therefore, it is possible to suppress the ignition timing from being delayed more than necessary. On the other hand, even if the judgment value is set larger than necessary and the knock intensity is lower than the judgment value frequently, the ignition timing may be advanced more than necessary, and the judgment value should be sufficiently high. By making it small, it is possible to prevent the ignition timing from being advanced more than necessary.

  An internal combustion engine ignition timing control device according to a fifth aspect of the present invention further includes storage means for storing a determination value in the reference region in addition to the configuration of any one of the first to fourth aspects. The setting means includes means for setting a determination value in another area so as to be a value corresponding to the stored determination value.

  According to the fifth aspect, the determination value corrected in the reference area is stored. Determination values in other areas are set so as to be values corresponding to the determination values. As a result, if only the determination value corrected in the reference region is stored, the determination frequency in other regions is not stored, but the knocking frequency in the internal combustion engine is considered. Can be obtained. Therefore, the capacity of storage means (for example, SRAM (Static Random Access Memory) etc.) for storing the determination value can be suppressed. As a result, the cost can be ultimately suppressed.

An ignition timing control device for an internal combustion engine according to a sixth aspect of the present invention includes a determination value set for the first region of the plurality of regions in addition to the configuration of any one of the first to fifth aspects. Based on the determination value for the first driving state and the determination value for the second driving state, the determination value set for the second region as the determination value for the second driving state. And means for setting a determination value for the third operating state.

  According to the sixth invention, the determination value set for the first region (the first region may be the reference region) of the plurality of regions is set as the determination value for the first operating state. The Similarly, the determination value set for the second region (the second region may be the reference region) is set as the determination value for the second operating state. Based on the determination values in these operating states, a determination value for the third operating state is set. Thereby, the determination value corresponding to the driving state can be obtained in more detail than the region.

  In the ignition timing control device for an internal combustion engine according to the seventh invention, in addition to the configuration of any one of the first to seventh inventions, the internal combustion engine is provided with a plurality of cylinders. A plurality of regions are set for each cylinder.

  According to the seventh invention, a plurality of regions are provided for one cylinder. Thereby, the determination value according to the frequency of occurrence of knocking in each cylinder can be obtained. Based on such a determination value, the ignition timing is retarded or advanced. Therefore, the ignition timing can be appropriately controlled for each cylinder.

  An ignition timing control device for an internal combustion engine according to an eighth aspect of the present invention relates to a calculation means for calculating a knock magnitude related to the magnitude of vibration caused by knocking based on the magnitude of vibration generated in the internal combustion engine, A control means for controlling the ignition timing of the internal combustion engine based on the result of comparison with the determined judgment value, a correction means for correcting the judgment value based on the occurrence frequency of knocking, A determination value that is corrected in the operation state within the region determined according to the operation state (output rotation speed, load (intake air amount), etc.) is set as a determination value in the predetermined operation state within the region. 1 setting means and an operation state different from the predetermined operation state, and a determination value in the operation state within the region is set based on the determination value in the predetermined operation state And a second setting means for.

According to the eighth 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. The ignition timing of the internal combustion engine is controlled based on the result of comparing the knock magnitude with the determination value. For example, if the knock intensity is greater than a predetermined 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 correct the determination value in accordance with the state of vibration generated in the internal combustion engine so that the frequency of ignition timing retard control is increased. . Therefore, the determination value is corrected based on the occurrence frequency of knocking. For example, when the occurrence frequency of knocking is higher than a predetermined frequency, the determination value is corrected to be small. Therefore, the ignition timing retarding control can be performed more. On the contrary, when the occurrence frequency of knocking is lower than a predetermined frequency, 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 corrected based on the occurrence frequency of knocking, and the ignition timing can be controlled appropriately. However, it is not always possible to obtain sufficient opportunities to correct the determination value in all operating states. Therefore, the determination value corrected in the operation state within the region determined according to the operation state of the internal combustion engine is set as the determination value in the predetermined operation state within the region. Thereby, even if there is no opportunity to correct the determination value in a predetermined driving state, it is possible to obtain a determination value corrected according to the occurrence frequency of knocking. The determination value in the operation state that is different from the predetermined operation state and in the region is set based on the determination value in the predetermined operation state. Thereby, the determination value corrected according to the frequency of occurrence of knocking can be obtained even in an operating state where the opportunity for correcting the determination value is small. Based on such a determination value, the ignition timing is retarded or advanced. Therefore, it is possible to provide an ignition timing control device for an internal combustion engine that can appropriately control the ignition timing.

  In the internal combustion engine ignition timing control apparatus according to the ninth aspect, in addition to the configuration of the eighth aspect, a plurality of regions are defined. The predetermined operating state is determined for each of a plurality of areas. The first setting means includes means for setting the corrected determination value as a determination value in a predetermined driving state for each of the plurality of regions. The second setting means includes means for setting, for each of the plurality of regions, a determination value in an operation state different from the predetermined operation state based on the determination value in the predetermined operation state.

  According to the ninth invention, a plurality of regions are defined. The predetermined operation state in which the determination value is set is determined for each of a plurality of areas. For each of the plurality of areas, the corrected determination value is set as a determination value in a predetermined operating state. Similarly, a determination value in an operation state different from the predetermined operation state is set for each of the plurality of areas based on the determination value in the predetermined operation state. Thereby, the determination value corrected according to the occurrence frequency of knocking can be obtained for each of a plurality of regions. Therefore, it is possible to obtain a determination value corresponding to the difference in the occurrence frequency of knocking due to the difference in the driving state included in each region. Based on such a determination value, the ignition timing is retarded or advanced. As a result, the ignition timing can be controlled appropriately.

  In the ignition timing control device for an internal combustion engine according to the tenth aspect, in addition to the configuration of the eighth or ninth aspect, the region is determined according to at least one of the output rotational speed and the load of the internal combustion engine. . The second setting means includes means for setting the determination value such that the determination value becomes larger as at least one of the output rotational speed and the load of the internal combustion engine is higher.

  According to the tenth invention, the region is determined according to at least one of the output rotational speed and the load of the internal combustion engine. The determination value is calculated so as to be larger as at least one of the output rotation speed and the load of the internal combustion engine is higher. As a result, a relatively large determination value can be obtained in a region where the output rotational speed and the load are large. For this reason, even in the case where knocking has not occurred, a state in which the knock strength is higher than the judgment value frequently occurs in a high rotation region or a high load region where vibration with a relatively large strength can occur, and ignition is performed more than necessary. It is possible to prevent the timing from being delayed.

  In the ignition timing control device for an internal combustion engine according to the eleventh aspect, in addition to the configuration of any of the eighth to tenth aspects, the internal combustion engine is provided with a plurality of cylinders. A region is set for each cylinder.

  According to the eleventh aspect of the present invention, regions are provided for each cylinder. Thereby, the determination value according to the frequency of occurrence of knocking in each cylinder can be obtained. Based on such a determination value, the ignition timing is retarded or advanced. Therefore, the ignition timing can be appropriately controlled for each cylinder.

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.

<First Reference Example >
With reference to FIG. 1, an engine 100 of a vehicle equipped with an ignition timing control device according to a first reference example of the present invention will be described. The engine 100 is provided with a plurality of cylinders. The ignition timing control apparatus according to this reference example 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
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. Engine ECU 200 performs arithmetic processing based on signals transmitted from each sensor and ignition switch 312, a map and a program stored in ROM (Read Only Memory) 202 and SRAM 204, and engine 100 enters a desired operating state. And control the equipment.

In this reference example , the engine ECU 200 determines a predetermined knock detection gate (from a predetermined first crank angle to a predetermined second crank angle based on a signal and a crank angle transmitted from the knock sensor 300. ) And a vibration waveform of the engine 100 (hereinafter referred to as a vibration waveform) is detected, and whether or not knocking has occurred in the engine 100 is determined based on the detected vibration waveform. The knock detection gate in this reference example 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 reference example , 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 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 this reference example , after the peak value of the vibration intensity, it is determined that the vibration intensity decreases as the crank angle increases, but the crank angle at which the vibration intensity reaches the peak value is defined. Is not defined.

The knock waveform model in this reference example 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 integrated value in the detected vibration waveform. The normalization method is not limited to this.

In this reference example , engine ECU 200 calculates a correlation coefficient K that is a value related to the deviation between the normalized vibration waveform and the 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 sum of ΔS (I). In this reference example , the 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. In addition, the maximum value P of the integrated value when calculating the knock magnitude N is logarithmically converted. Further, the calculation method of knock strength N is not limited to this.

  BGL is calculated as a value obtained by subtracting the product of the standard deviation σ and a coefficient (for example, “1”) from the median value V (50) in the frequency distribution of intensity values LOG (V) described later. Note that the BGL calculation method is not limited to this, and the BGL may be stored in the ROM 202.

In this reference example , the engine ECU 200 compares the calculated knock magnitude N with the determination value V (KX) stored in the SRAM 204, and further compares the detected waveform with the stored knock waveform model. Whether or not knocking has occurred in engine 100 is determined for each ignition cycle.

As shown in FIG. 7, the determination value V (KX) is stored as a map for each region divided by the operating state using the engine speed NE and the intake air amount KL (load) as parameters. In this reference example , low rotation (NE <NE (1)), medium rotation (NE (1) ≦ NE <NE (2)), high rotation (NE (2) ≦ NE), low load (KL <KL (1)) Nine regions are provided for each cylinder by dividing the load into medium loads (KL (1) ≦ KL <KL (2)) and high loads (KL (2) ≦ KL). The number of areas is not limited to this. Further, the region may be divided using parameters other than the engine speed NE and the intake air amount KL.

  When the engine 100 or the vehicle is shipped, a value determined in advance through experiments or the like is used as the determination value V (KX) (initial value of the determination value V (KX) at the time of shipment) stored in the ROM 202. 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 this reference example , the frequency indicating 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. Based on the 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 this reference example , median V (50) and standard deviation σ approximated to median and standard deviation calculated based on a plurality of (for example, 200 cycles) intensity values LOG (V) are calculated as follows. It is calculated every ignition cycle by the 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 frequency distribution of the intensity value LOG (V) is created for each region described above, and the determination value V (KX) for each region is corrected.

  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 this reference example , as shown in FIG. 12, the intensity value LOG (V) larger than the threshold value V (1) is obtained by using the intensity value LOG (V) in the region surrounded by the broken line. The median value V (50) and standard deviation σ are calculated by excluding them. 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, among the intensity values LOG (V) smaller than the threshold value V (1), the intensity value LOG (V) calculated in the ignition cycle in which the correlation coefficient K is larger than the threshold value K (1) is used. You may make it extract.

Referring to FIG. 13, control of a program executed by engine ECU 200, which is an ignition timing control device according to the present reference example , determines whether or not knocking has occurred and controls ignition timing for each ignition cycle. The 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 FIGS. 14 and 15, a control structure of a program executed by engine ECU 200, which is an ignition timing control device according to the present reference example , to set determination value V (KX) when engine 1000 is started. explain.

  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 each time intensity values LOG (V) for N (N is a natural number, for example, N = 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 intensity values LOG (V) for N cycles have been extracted since the last determination value V (KX) was corrected. If intensity values LOG (V) for N 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 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 S212), the process proceeds to S214. If not (NO in S212), the process proceeds to S216.

  In S214, engine ECU 200 decreases determination value V (KX) by a predetermined correction amount. In S216, engine ECU 200 increases determination value V (KX) by a predetermined correction amount.

In S300, engine ECU 200 determines that NE (1) ≦ engine speed NE <NE (2
) And whether or not the determination value V (KX) in the mid-rotation load region (hereinafter, this region is also referred to as a normal region) where KL (1) ≦ intake air amount KL <KL (2) is corrected. Is determined. If determination value V (KX) in the regular area is corrected (YES in S300), the process proceeds to S400. If not (NO in S300), the process proceeds to S500.

  In S400, engine ECU 200 stores determination value V (KX) in the normal area in SRAM 204. Thereafter, this process ends.

  In S500, engine ECU 200 determines whether or not determination value V (KX) in the normal area is stored in SRAM 204. If determination value V (KX) in the regular area is stored in SRAM 204 (YES in S500), the process proceeds to S502. If not (NO in S500), this process ends.

  In S502, engine ECU 200 sets determination value V (KX) of the corrected region so as to be within the range of determination value V (KX) ± X (X is a positive number) in the normal region. That is, the determination value V (KX) in the region other than the normal region is corrected within a range of ± X with reference to the determination value V (KX) in the normal region.

  At this time, if the determination value V (KX) is within the range of the determination value V (KX) ± X in the regular area, the value is maintained.

  When the determination value V (KX) exceeds the determination value V (KX) + X in the normal area (exceeds the upper limit value) by the correction, the determination value V (KX) becomes the determination value V (KX) + X (the upper limit in the normal area). Value).

  When the determination value V (KX) is lower than the determination value V (KX) -X in the normal area (lower than the lower limit value) due to the correction, the determination value V (KX) is the determination value V (KX) -X in the normal area. Set to (lower limit). Thereafter, this process ends.

An operation of engine ECU 200 that is the ignition timing control device according to the present reference example 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 detect the vibration waveform in which fine changes are suppressed. 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.

Therefore, in engine ECU 200 that is the ignition timing control device according to the present reference example , 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 determination level V (KD) is counted as the knock occupancy KC (S208). Intensity value LOG (V) for N cycles has been extracted since the previous determination value V (KX) was corrected (YES in S210), and knock occupancy KC is greater than threshold value KC (0) ( (YES in S212), determination value V (KX) is decreased (S214) so that the frequency of ignition timing retard control (S118) is increased. When knock occupancy KC is smaller than threshold value KC (0) (NO in S212), determination value V (KX) is increased so that the frequency of ignition timing advance control (S122) is increased. (S216). Accordingly, the determination value V (KX) in the knocking determination for each ignition cycle is appropriately corrected,
The ignition timing can be appropriately controlled.

  However, it is not always possible to obtain sufficient opportunities to correct the determination value V (KX) in all regions. For example, it is rare to operate the engine 100 in a low rotation high load region, a high rotation low load region, or the like. Further, the opportunity to operate the engine 100 in the low rotation / low load region and the high rotation / high load region is less than the opportunity to operate the engine 100 in the middle rotation / intermediate load region (normal region).

  In a region where there are few opportunities to drive, there are fewer opportunities to correct the determination value V (KX). Therefore, it is considered that the determination value V (KX) in the region where the driving opportunity is small has a large influence when it is erroneously corrected and has low reliability.

  Therefore, when determination value V (KX) in the regular area where it is considered that there are many opportunities to correct determination value V (KX) is corrected (YES in S300), this determination value V (KX) is stored in SRAM 204. (S400), the determination value V (KX) in the area other than the normal area is set so as to be within the range of the determination value V (KX) ± X in the normal area.

  Specifically, when determination value V (KX) in an area other than the normal area is corrected (NO in S300), if determination value V (KX) in the normal area is stored in SRAM 204 (in S500) YES), the determination value V (KX) of the corrected region is set so as to be within the range of the determination value V (KX) ± X in the normal region (S502).

  If the determination value V (KX) is within the range of the determination value V (KX) ± X in the regular area, that value is maintained. Thereby, in a region where an opportunity to correct the determination value V (KX) can be obtained, a determination value V (KX) that takes into account the occurrence of knocking in that region can be obtained.

  When the determination value V (KX) exceeds the determination value V (KX) + X in the normal area by the correction, the determination value V (KX) is set to the determination value V (KX) + X in the normal area. When the determination value V (KX) falls below the determination value V (KX) -X in the normal area due to the correction, the determination value V (KX) is set to the determination value V (KX) -X in the normal area. As a result, an opportunity to correct the determination value V (KX) can be obtained, but even when there is a possibility that the determination value V (KX) is corrected by mistake, the determination value V (KX) becomes excessive or insufficient. This can be suppressed.

As described above, according to the engine ECU that is the ignition timing control device according to this reference example , the engine is operated frequently and there are many opportunities to correct the determination value V (KX) based on the occurrence frequency of knocking. The determination value V (KX) outside the normal area is set so as to be a value within the range of the determination value V (KX) ± X in the normal area. Thereby, an opportunity to correct the determination value V (KX) can be obtained, but even when there is a possibility that the determination value V (KX) is corrected by mistake, the determination value V (KX) becomes excessive or small. This can be suppressed. Therefore, in each region, the ignition timing can be retarded or advanced using the determination value V (KX) appropriately corrected based on the occurrence frequency of knocking. As a result, the ignition timing can be appropriately controlled from the start of the engine.

In this reference example , the middle rotation intermediate load region is used as a normal region, and the determination value V (KX) in another region is set so as to be the determination value V (KX) ± X in this region. The setting range of the value V (KX) may be set for each region.

FIG. 16 shows a setting range of the determination value V (KX) in another region when the determination value V (KX) in the middle rotation load region (normal region) is “D”. As shown in FIG. 16, the reference value (“D + Y” portion) of the setting range of the determination value V (KX) and the width of the setting range (“± X” portion) are set for each region.

  In this case, the median of the setting range of the determination value V (KX) and the width of the setting range are set to be larger as the rotation speed is higher, or to be larger as the load is higher. May be. This is because the vibration generated in the engine 100 increases as the engine speed increases and the load increases, and the knock intensity N calculated using the peak value of the intensity of vibration increases. By setting the setting range of the determination value V (KX) for each region, an appropriate determination value V (KX) corresponding to each region can be obtained.

  Depending on the characteristics of engine 100, the median of the setting range of determination value V (KX) and the width of the setting range are set so as to increase as the speed decreases, or increase as the load decreases. It may be set as follows.

<Second Reference Example >
The second reference example of the present invention will be described below. In the present reference example , when the engine 100 is started, the determination value V (KX) in the other region is set based on the determination value V (KX) in the middle-rotation load region (normal region). This is different from the first reference example . Other structures are the same as those in the first reference example described above. The same applies to their functions. Therefore, detailed description thereof will not be repeated here.

With reference to FIG. 17, a control structure of a program executed by engine ECU 200 that is the ignition timing control device according to the present reference example will be described. The program described below is executed in addition to the program in the first reference example described above.

  In S600, engine ECU 200 determines whether engine 100 that has been stopped has been started or not. For example, when engine speed NE rises above a threshold value, it is determined that engine 100 has been started. If engine 100 in the stopped state is started (YES in S600), the process proceeds to S602. If not (NO in S600), the process returns to S600.

  In step S602, the engine ECU 200 determines that the intermediate rotational speed load range (normal range) where NE (1) ≦ engine speed NE <NE (2) and KL (1) ≦ intake air amount KL <KL (2). It is determined whether or not the determination value V (KX) is stored in the SRAM 204. If determination value V (KX) in the regular area is stored in SRAM 204 (YES in S602), the process proceeds to S604. If not (NO in S602), the process proceeds to S608.

  In S604, engine ECU 200 reads determination value V (KX) in the normal area from SRAM 204. In S606, engine ECU 200 sets determination value V (KX) in the region other than the normal region to the same determination value V (KX) as determination value V (KX) in the normal region. Thereafter, this process ends.

  In S608, engine ECU 200 reads determination value V (KX) stored in ROM 202. Thereafter, this process ends.

An operation of engine ECU 200 that is the ignition timing control device according to the present reference example based on the above-described structure and flowchart will be described.

As described in the first reference example , when the determination value V (KX) in the normal area is corrected, the corrected determination value is stored in the SRAM (S400). Here, the SRAM 204 is a non-volatile memory, and continues to store the determination value V (KX) unless the power supply to the SRAM 204 is interrupted by replacing the auxiliary battery 320 or the like.

  Therefore, when engine 100 is started again after engine 100 is stopped (YES in S600), determination value V (KX) is stored in SRAM 204 (YES in S602). (KX) is read (S604).

  The determination value V (KX) in the area other than the regular area is set to the same value as the determination value V (KX). As a result, only the determination value V (KX) in the normal area is stored in the SRAM 204, and the initial value of the determination value V (KX) with high reliability for each trip (between starting and stopping the engine 100) is set. Values can also be obtained in regions other than the regular region. Therefore, even in a region where the opportunity to correct the determination value V (KX) is rare, although it is not the occurrence frequency of knocking in that region, the determination value V (appropriately corrected according to the occurrence frequency of knocking in the engine 100) KX) can be obtained.

As described above, according to the engine ECU which is the ignition timing control device according to the present reference example , the determination value V (in the region other than the normal region is based on the determination value V (KX) in the normal region stored in the SRAM. KX) is set. As a result, it is possible to obtain a highly reliable determination value V (KX) in an area other than the normal area only by storing only the determination value V (KX) in the normal area in the SRAM. For this reason, even in an area where the determination value V (KX) is rarely corrected, the determination value V (KX) appropriately corrected according to the occurrence frequency of knocking in the engine, although not the occurrence frequency of knocking in that area. ) Can be obtained. In addition, since the determination value V (KX) stored in the SRAM can be set to only the determination value V (KX) in the regular area, the performance (capacity) of the SRAM can be suppressed, and ultimately the cost can be suppressed. it can.

  Instead of setting the determination value V (KX) in the area other than the normal area to the same determination value V (KX) as the determination value V (KX) in the normal area, the determination value V in the normal area is set for each area. A value obtained by adding or subtracting a coefficient to (KX) may be set. In this case, the determination value V (KX) may be increased or decreased in a higher rotation region or a higher load region.

<Third reference example >
The third reference example of the present invention will be described below. In the present reference example , the above-mentioned first reference is provided in that the determination value V (KX) corresponding more precisely to the operating state of the engine 100 is set based on the determination value V (KX) set for each region. It is different from the example and the second reference example . Other structures are the same as those in the first reference example described above. The same applies to their functions. Therefore, detailed description thereof will not be repeated here.

  As shown in FIG. 18, the determination value V (KX) set in each area is assumed to be the determination value V (KX) at the center point in that area. For example, the determination value V (KX) in the middle rotation / intermediate load region (NE (1) ≦ engine speed NE <NE (2) and KL (1) ≦ intake air amount KL <KL (2)). Is assumed to be a determination value of NE (3) = (NE (1) + NE (2)) / 2 and KL (3) = (KL (1) + KL (2)) / 2. The determination value V (KX) in each region may be assumed to be the determination value V (KX) at a point (operating state) other than the center point.

As shown in FIG. 18, the determination value V (KX) in the driving state located on the straight line connecting any two central points is set based on the determination value V (KX) at the central point. As shown in FIG. 19, a straight line equation between the intake air amount KL and the determination value V (KL) is obtained, and the determination value V (KL) is calculated from this equation. Thereby, the determination value V (KL) corresponding to a more detailed driving | running state can be obtained. It should be noted that a straight line equation formed between the engine speed NE and the determination value V (KL) may be obtained, and the determination value V (KL) may be calculated from this equation.

As described above, according to engine ECU 200 that is the ignition timing control device according to the present reference example , determination value V (KX) in each region is assumed to be determination value V (KX) at the center point of each region. The A determination value V (KX) in an operating state located on a straight line connecting any two center points is set based on the determination value V (KX) at these center points. Thereby, the determination value V (KX) corresponding to a more detailed driving | running state can be obtained.

< Embodiment >
Embodiments of the present invention will be described below. In the present embodiment, the corrected determination value V (KX) is set as the determination value V (KX) at the center point of the region where the determination value V (KX) is corrected, and other operating states in the region Is different from the first reference example described above in that the determination value V (KX) is set based on the determination value V (KX) at the center point. Other structures are the same as those in the first reference example described above. The same applies to their functions. Therefore, detailed description thereof will not be repeated here.

Referring to FIG. 20, a control structure of a program executed by engine ECU 200, which is the ignition timing control device according to the present embodiment, to set determination value V (KX) will be described. In addition, the same step number is attached | subjected about the same process as the program in the above-mentioned 1st reference example . Therefore, detailed description thereof will not be repeated here.

  In S700, engine ECU 200 sets corrected determination value V (KX) as determination value V (KX) at the center point of the region where determination value V (KX) is corrected. For example, the determination value V corrected in the middle-rotation load range (NE (1) ≦ engine speed NE <NE (2) and KL (1) ≦ intake air amount KL <KL (2)). (KX) is NE (3) = (NE (1) + NE (2)) / 2, and the determination value V (KX) at KL (3) = (KL (1) + KL (2)) / 2. Set as The determination value V (KX) corrected in each region may be set as the determination value V (KX) at a point (operating state) other than the center point. Further, the corrected determination value V (KX) may be further corrected and set as the determination value V (KX) at the center point.

  In S702, engine ECU 200 sets determination value V (KX) in another operating state in each region based on determination value V (KX) at the center point. For example, by adding or subtracting a correction amount determined by a map using the displacement amount from the center point for the engine speed NE and the intake air amount KL as a parameter to the determination value V (KX) at the center point. The determination value V (KX) in other operating states in the region is set. The determination value V (KX) is set to be larger as the engine speed NE is larger than the center point. Similarly, the determination value V (KX) is set to be larger as the intake air amount KL is larger than the center point.

  An operation of engine ECU 200 that is the control device according to the present embodiment based on the structure and flowchart as described above will be described.

When the determination value V (KX) is reduced (S214), the determination value V (KX) is increased (S216), and the determination value V (KX) is corrected, as shown in FIG. The determined determination value V (KX) is set as the determination value V (KX) at the center point of the region where the determination value V (KX) is corrected (S700). That is, the determination value V (KX) corrected in the operation state in each region is set as the determination value V (KX) at the center point of each region.

  As shown in FIG. 22, based on the determination value V (KX) at the center point, the determination value V (KX) in another operating state in each region is set (S702). Thereby, the determination value V (KL) corresponding to a more detailed driving | running state can be obtained.

  As described above, according to engine ECU 200 that is the ignition timing control device according to the present embodiment, corrected determination value V (KX) is determined at the center point of the region where determination value V (KX) is corrected. Set as the value V (KX). Thereby, even if there is no opportunity to correct the determination value V (KX) at the center point, the determination value V (KX) corrected according to the occurrence frequency of knocking can be obtained. Determination value V (KX) in other operating states in the region is set based on determination value V (KX) at the center point. Thereby, the determination value V (KX) corrected according to the frequency of occurrence of knocking can be obtained even in an operating state where there is little opportunity to correct the determination value V (KX). The ignition timing is retarded or advanced based on such a determination value V (KX). Therefore, it is possible to appropriately control the ignition timing.

<Other embodiments>
As shown in FIG. 23, when the intensity of vibration due to noise is large, the difference between the maximum integrated value during knocking and the maximum integrated value due to noise is small, and knocking and noise are distinguished from knock intensity N. May be difficult. 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. 24, since the generation period of vibration due to noise is shorter than the generation period of vibration due to knocking, the total sum of 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.

1 is a schematic configuration diagram showing an engine controlled by an engine ECU that is an ignition timing control device according to a first 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. It is a figure which shows the map of the determination value V (KX) memorize | stored in ROM or SRAM 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 a figure which shows intensity value LOG (V) used in order to create frequency distribution of intensity value LOG (V). It is a flowchart (the 1) which shows the control structure of the program which engine ECU which is the ignition timing control apparatus which concerns on the 1st Embodiment of this invention performs. It is a flowchart (the 2) which shows the control structure of the program which engine ECU which is the ignition timing control apparatus which concerns on the 1st Embodiment of this invention performs. It is a flowchart (the 3) which shows the control structure of the program which engine ECU which is the ignition timing control apparatus which concerns on the 1st Embodiment of this invention performs. It is a figure which shows the judgment value V (KX) set for every area | region. It is a flowchart which shows the control structure of the program which engine ECU which is an ignition timing control apparatus which concerns on the 2nd Embodiment of this invention performs. It is a figure which shows the center point of each area | region. It is a figure which shows the judgment value V (KX) in a center point. It is a flowchart which shows the control structure of the program which engine ECU which is an ignition timing control apparatus which concerns on the 4th Embodiment of this invention performs. It is a figure which shows the center point of each area | region. It is a figure which shows the driving | running state by which the determination value V (KX) is set based on the determination value V (KX) in a center point. 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, 202 ROM, 204 SRAM, 300 knock sensor, 302 water temperature sensor, 304 timing rotor, 306 crank position Sensor, 308 Throttle opening sensor, 314 Air flow meter, 320 Auxiliary battery.

Claims (4)

An ignition timing control device for an internal combustion engine,
A calculation means for calculating a 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 a result of comparing the knock intensity with a predetermined determination value;
Correction means for correcting the determination value based on the occurrence frequency of knocking;
First setting means for setting a determination value corrected in an operation state within a region determined according to the operation state of the internal combustion engine as a determination value in a predetermined operation state within the region;
A second setting means for setting a determination value in the driving state within the region based on the determination value in the predetermined driving state, the driving state being different from the predetermined driving state; An ignition timing control device for an internal combustion engine, comprising: A plurality of the regions are defined,
The predetermined operating state is determined for each of the plurality of regions,
The first setting means includes means for setting, for each of the plurality of regions, the corrected determination value as a determination value in the predetermined driving state,
The second setting means is means for setting, for each of the plurality of regions, a determination value in an operation state different from the predetermined operation state based on the determination value in the predetermined operation state. The ignition timing control device for an internal combustion engine according to claim 1 , comprising: The region is determined according to at least one of the output rotational speed and the load of the internal combustion engine,
Said second setting means includes means for setting a determination value as at least one is greater than the higher of the output speed and load of the internal combustion engine, according to claim 1 or 2 Ignition timing control device for internal combustion engine. The internal combustion engine is provided with a plurality of cylinders,
The ignition timing control device for an internal combustion engine according to any one of claims 1 to 3 , wherein the region is set in each of the cylinders.

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