JPH06186114A - Method and apparatus for control of knock - Google Patents

Abstract

PURPOSE:To comply easily with a difference in the type and the specifications of an internal combustion engine and to detect a knock with high accuracy. CONSTITUTION:In response to the output of a crank angle sensor, the period of a prescribed crank angle is set as obervation periods W1 in a period until the piston of a next cylinder reaches an upper end point after the piston of a cylinder entering an ignition stroke has reached an upper end point. The frequency of the output of a knock sensor is analyzed inside the observation periods W1. On the basis of the spectral distribution of its analyzed result, e.g. maximum values of spectral power are set as index values S1, S2,.... On the basis of the running average of the spectral power of the index values S1, S2,..., a knock judgment reference V is formed, and the ignition time is controlled so as to correspond to a judged result using the knock judgment reference V.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a knocking control method and device suitably implemented in an ignition timing control device for an internal combustion engine.

[0002]

2. Description of the Related Art In the conventional knocking control method for controlling the ignition timing of an internal combustion engine,
Of the output from the knock sensor that detects vibration due to knocking of the internal combustion engine, only the frequency component due to knocking is filtered by a bandpass filter, and the presence or absence of knocking is determined by discriminating the level of the filtered output. It is configured to control the ignition advance amount correspondingly. The knock sensor is realized by a so-called piezo-type acceleration sensor attached to the cylinder block, a pressure sensor for detecting the cylinder internal pressure, or the like.

[0003]

In the above-mentioned prior art,
The center frequency of the bandpass filter is selected to be a typical value of the resonance frequency of the cylinder block due to knocking, for example, 7.1 kHz. However, in reality, the resonance frequency changes as shown in FIG. 13 (2) corresponding to each of the plurality of resonance modes shown in FIG. 13 (1). FIG. 13 (1) is a diagram showing the pressure distribution in the cylinder. Reference numeral + indicates a region where the pressure is relatively high, and reference numeral − indicates a region where the pressure is relatively low.

As is clear from FIG. 13 (2), the resonance frequency greatly differs when the resonance mode is different, and the resonance frequency depends on the number of cylinders of the internal combustion engine and the distance difference between the cylinder to be detected and the sensor. Also changes. Therefore, there is a problem in that the resonance frequency varies depending on the type and specifications of the internal combustion engine, and matching of the resonance frequencies of the bandpass filter becomes complicated.

Further, from the viewpoint of exhaust gas purification and fuel consumption reduction, automobile manufacturers are trying to improve these by increasing the compression ratio. However, in order to reduce the influence of the resonance frequency component other than 7.1 kHz which increases as the rotation speed becomes higher, the ignition timing at the high rotation speed is retarded more than the optimum value at the low rotation speed.

It is an object of the present invention to provide a knocking control method and device which can easily cope with different types and specifications of internal combustion engines and can detect knocking with high accuracy.

[0007]

According to the present invention, a knocking observation period is set at a predetermined timing between the top dead centers of pistons in response to the output of a crank angle sensor, and the frequency of the output of the knock sensor during the observation period is set. Perform an analysis, set the value calculated based on the spectrum power over the observation period to the index value from the spectrum distribution of the analysis result, perform knocking determination based on the index value, and respond to the determination result. The knocking control method is characterized by controlling the ignition advance angle.

Further, according to the present invention, in response to the output of the crank angle sensor, the knocking observation period is set at a predetermined timing between the top dead centers of the pistons, and the frequency of the output of the knock sensor is analyzed during the observation period. From the spectrum distribution of the analysis result, a frequency band that may contain a signal component indicating the occurrence of knocking is preset over the observation period, and a value calculated based on the spectrum power in this frequency band is set. Set to the index value, create a knocking judgment standard based on the index value, perform knocking judgment from whether the maximum value of the spectrum power at all frequencies is above this judgment standard, and respond to the judgment result. The knocking control method is characterized by controlling the ignition advance angle.

Further, according to the present invention, a knocking observation period is set at a predetermined timing between the top dead centers of the pistons in response to the output of the crank angle sensor, and the frequency of the knock sensor output is analyzed during the observation period. From the spectrum distribution of the analysis result, a frequency band that may include a signal component indicating the occurrence of knocking is preset over the observation period, and a value calculated based on the spectrum power in this frequency band. Is set as an index value, and a knocking determination standard is created based on the index value,
Knocking is determined based on whether or not the maximum value of the spectrum power in the frequency band that may include the signal component indicating the occurrence of knocking is equal to or greater than this criterion, and ignition progress is performed according to the result of the determination. It is a knocking control method characterized by controlling a corner.

Further, according to the present invention, in response to the output of the crank angle sensor, a knocking observation period is set at a predetermined timing between the top dead centers of the pistons, and the frequency of the output of the knock sensor is analyzed during the observation period. From the spectrum distribution of the analysis result, a plurality of frequency bands that may include a signal component indicating the occurrence of knocking are preset over the observation period, and are calculated based on the spectrum power in each frequency band. The determined value is set as an index value, a knocking determination standard is created based on the index value, and the knocking determination is performed based on whether or not the maximum value of the spectrum power at all frequencies is equal to or greater than this determination standard, and the determination is made. The knocking control method is characterized by controlling the ignition advance angle in accordance with the result.

Further, according to the present invention, in response to the output of the crank angle sensor, a knocking observation period is set at a predetermined timing between the top dead centers of the pistons, and the frequency of the output of the knock sensor is analyzed during the observation period. From the spectrum distribution of the analysis result, a plurality of frequency bands that may include a signal component representing the occurrence of knocking are preset over the observation period, and based on the spectrum power in each frequency band. The calculated value is set as an index value, a knocking determination standard is created based on the index value, and the maximum value of the spectrum power in each frequency band that may include a signal component representing the occurrence of the knocking. Knocking judgment is made based on whether or not is above this judgment criterion, and the ignition advance angle can be controlled according to the judgment result. A knock control method according to claim.

According to the present invention, the knocking observation period is set at a predetermined timing between the top dead centers of the pistons in response to the output of the crank angle sensor, and the frequency of the output of the knock sensor is analyzed during the observation period. From the spectrum distribution of the analysis result, a plurality of frequency bands that may include a signal component indicating the occurrence of knocking are preset over the observation period, and based on the spectrum power of each frequency band. The calculated value is set as an index value, a knocking determination standard is created for each of the frequency bands based on the index value, and at least one of the spectrum powers in the corresponding frequency band is equal to or greater than the determination standard. Knocking control characterized by performing knocking determination based on whether or not there is, and controlling the ignition advance angle according to the determination result. It is the law.

Furthermore, the index value of the present invention is set to the maximum value of the spectrum power.

Further, the index value of the present invention is set to an addition value of spectrum powers of a frequency at which the spectrum power is maximum and a frequency adjacent to the frequency.

Further, the index value of the present invention is a plurality of frequencies representing the peak value of the spectrum power,
It is characterized in that it is set to the maximum value of the added value of the spectrum power with the frequency adjacent to the frequency.

Further, the index value of the present invention is set to an added value of the spectrum power over the entire frequency band.

Furthermore, the present invention provides a knock sensor for detecting knocking of an internal combustion engine, a crank angle sensor for detecting a rotational angle position of the internal combustion engine, and a piston of the internal combustion engine in response to an output of the crank angle sensor. Analyzing means for performing frequency analysis of the output from the knock sensor in a knocking observation period set during a predetermined timing between dead points, and an index value setting for obtaining an index value over the observation period from the analysis result of the analyzing means. The knocking control device is characterized by including a means and a control means for performing knocking determination based on the index value and controlling the ignition advance angle in accordance with the determination result.

[0018]

According to the present invention, in response to the output of the crank angle sensor, when the internal combustion engine is, for example, a 4-cylinder 4-cycle internal combustion engine, every 180 ° crank angle (hereinafter referred to as ° CA), or In the case of 6 cylinders, in every 120 ° CA, in the period from when the piston of a certain cylinder reaches the top dead center to when the piston of the next cylinder reaches the top dead center,
For example, the knocking observation period is set between 10 ° and 110 ° CA from the top dead center. In the observation period, the frequency analysis of the output of the knock sensor realized by the piezoelectric element or the like is performed, that is, the spectrum power at each frequency is analyzed.

From the spectrum distribution of the analysis result, for example, the maximum value of all the spectrum power over the observation period is set as an index value, or the sum value of the spectrum power of the maximum frequency and the frequency adjacent to the frequency is set. To the index value, or set the maximum value of the sum of the spectrum power of a plurality of frequencies representing the peak value of the spectrum power and the frequency adjacent to the frequency to the index value, or in the entire frequency band The added value of the spectrum power over the range is set as the index value.

Based on the index value thus obtained, for example, an average value of the index values up to a value prior to the predetermined calculation timing is set as the knocking determination standard, and when the current index value is higher than this determination standard. It is determined that knocking has occurred, and the ignition advance amount is controlled to be small.

Therefore, the knocking component is accurately extracted from the output of the knocking sensor for the knocking determination regardless of the difference in the type and specifications of the number of cylinders of the internal combustion engine, or the difference in the knocking vibration mode. This can be performed, the versatility can be improved, and the determination accuracy can be improved.

Further, according to the present invention, after the frequency analysis is performed, from the spectrum distribution of the analysis result, only the frequency band including the signal component indicating the occurrence of knocking, that is, the noise component due to the valve vibration is included. The index value is set in the remaining frequency band excluding the frequency band. Based on the knocking determination standard created based on the index value, knocking determination is performed based on whether or not the maximum value of spectrum power at all frequencies is large.

Further, as another embodiment of the present invention, the maximum value of the spectrum power within only the frequency band in which the signal component representing the occurrence of the knocking may be included with respect to the knocking criterion is: The knocking determination may be performed based on whether or not the determination criterion is equal to or more than this.

Further, according to the present invention, there is a possibility that the signal component indicating occurrence of knocking is included, for example, 7k.
Hz, 11 kHz, 13 kHz, 15 kHz and 19
A plurality of frequency bands are set in advance with a frequency such as kHz as the center frequency. In the set frequency band, for example, the maximum value of the spectrum power, or the addition value of the spectrum power between the maximum frequency and the frequency adjacent to the frequency, or a plurality of the peak values of the spectrum power are displayed. The maximum value of the added value of the spectrum power of each frequency and the frequency adjacent to the frequency or the added value of the spectrum power over the entire frequency band is set as the index value.

Based on the index value set in this way, for example, an average value of the index values up to a value before the predetermined calculation timing is set as the knocking determination standard. With respect to this knocking determination standard, knocking determination is performed when the maximum value of the spectrum power at all frequencies is equal to or higher than this determination standard.

Further, as another embodiment of the present invention, the maximum value of the spectrum power within only the frequency band that may include the signal component representing the occurrence of the knocking with respect to the knocking determination criterion is: The knocking determination may be performed based on whether or not the determination criterion is equal to or more than this.

Further, according to the present invention, the index value is set for each of the plurality of frequency bands that may include the signal component representing the occurrence of knocking in the same manner as described above. A knocking determination standard is created based on this index value as described above, and knocking occurs when the spectrum power in the frequency band corresponding to each determination standard is larger than any one of the determination standards. To determine.

Further, according to the present invention, in performing the knocking determination as described above, a knock sensor which is realized by a piezoelectric element or the like and is mounted on a cylinder block or the like, and a crank angle sensor for detecting the rotational angular position of the crankshaft. And an analysis means for performing the frequency analysis, and an index value setting means for obtaining the index value from the analysis result,
Based on the obtained index value, the control means makes knocking determination as described above, and controls the ignition advance angle according to the determination result.

[0029]

1 is a block diagram showing an electrical configuration of an ignition timing control system 1 for an internal combustion engine in which a knocking control method according to an embodiment of the present invention is used. The knock sensor 2, which is realized by a piezoelectric element such as a so-called piezo-type acceleration sensor, is fixed to a cylinder block of an internal combustion engine. The output from the knock sensor 2 is input to the analog / digital converter 4 via a low-pass filter (abbreviated as LPF) 3 having a cutoff frequency of 20 kHz, for example, in order to prevent aliasing noise.

On the other hand, from the crank angle sensor 5 provided for detecting the rotational angle position of the internal combustion engine, each time the piston of the cylinder about to enter the ignition stroke reaches the top dead center, that is, for example, the internal combustion engine. Is a 4-cylinder 4-cycle internal combustion engine, a crank pulse is derived every 180 ° CA, and when it is 6-cylinder, 120 ° CA
A crank pulse is derived every time. The crank pulse is input to the sampling signal generating circuit 7 via the input interface circuit 6. A sampling signal is derived from the sampling signal generation circuit 7 in response to the crank pulse, and the analog / digital converter 4 outputs the sampling signal.
Converts the output from the knock sensor 2 into a digital value at a sampling frequency of, for example, 40 kHz in synchronization with the sampling signal, and then outputs the digital value to the frequency analyzer 8.

The frequency analyzer 8 is realized by a so-called digital signal processor or the like, and carries out frequency analysis of the knock sensor output converted into a digital value by a fast Fourier transform method in synchronization with the sampling signal. , And outputs the analysis result to the knocking determination circuit 9. The knocking determination circuit 9 determines a knocking signal from the knocking frequency created based on the output of the frequency analyzer 8 and the knocking frequency band width and signal level to be filtered in order to pass only the knocking signal, as described later. Based on the knocking determination standard V, it is determined whether or not knocking has occurred, and the determination result is derived to the control circuit 11 realized by a microcomputer or the like.

In association with the control circuit 11, there are provided an intake pressure sensor 12, a cooling water temperature sensor 13, and other sensors 14 such as an intake temperature sensor and a throttle valve opening sensor. The detection result of 14 is input to the analog / digital converter 16 via the input interface circuit 15, converted into a digital value, and then input to the control circuit 11. The crank pulse from the crank angle sensor 5 is also input to the control circuit 11, and the control circuit 11 responds to the crank pulse by the determination result of the knocking determination circuit 9 and the sensor 1.
The ignition advance amount is calculated based on the detection results of 2 to 14.
The control circuit 11 outputs an ignition signal to the igniter 18 via the output interface circuit 17 so that the ignition advance amount thus calculated is obtained, and the ignition timing of the ignition plug 19 is drive-controlled. In this way, it is possible to suppress the occurrence of knocking and perform ignition timing control with a large ignition advance amount.

FIG. 2 is a diagram for explaining the basic idea of the knocking determination method of the present invention. 2 (1) from the knock sensor 2, the observation period W1 is between the top dead center (TDC) of the piston, when the period W2, for example, 10 ° CA, elapses from the top dead center. To 110 ° CA, for example.

Now, when the internal combustion engine has four cylinders and four cycles, and the rotation speed of the internal combustion engine detected by the crank angle sensor 5 is 3000 rpm, the interval between the top dead centers is 180.
It becomes CA, and the time becomes 10 msec. Also,
The start time of the observation period W1 after the period W2 has elapsed is a time point after 0.56 msec from the top dead center,
The end of the observation period W1 is 6.11 m from the top dead center.
This is the time when sec has elapsed.

The frequency analyzer 8 analyzes the spectrum power at each of a plurality of frequencies, as shown in FIG. 2B, based on all the sampling data within the observation period W1. Based on the analysis result, the knocking determination circuit 9 detects each observation period W as shown in FIG.
The maximum value Pa in 1 is the index values Si, S (i + 1), S
(I + 2), ... (Generally indicated by reference symbol S), and filter calculation is performed from these index values as shown in Expression 1 to obtain a knocking determination reference V.

V = [S (i-1) + S (i-2) + ... S (i-8)] / 8 (1) That is, from the previous index value S (i-1), before 7 calculation cycles The moving average value up to the index value S (i-8) of is set as the knocking determination standard V.

The knocking determination circuit 9 determines that knocking has occurred when the index value Si of this time exceeds the knocking determination reference V thus obtained, and the control circuit 1
The ignition advance amount is reduced to 1. In this way, the ignition timing control corresponding to the output of the knock sensor 2 is performed.

However, the calculation represented by the above equation 1 is performed only when it is determined that knocking has not occurred, and the knocking determination reference V is updated. That is, for example, when it is determined that knocking occurs at the index values S (i-3) and S (i-4), these data are deleted from the calculation of the knocking determination reference V,
Therefore, the knocking determination standard V is calculated and updated using the data up to the index value S (i-10).

FIG. 3 is a flow chart for explaining a concrete index value setting operation. In step m1, the count value i of the counter is reset to 0. The minimum value of the count value i is 0, and the maximum value is an integer value of (fn-f0) / fd when the analysis target frequency is f0 to fnHz and the resolution of the frequency analyzer 8 is fdHz. Become.

At step m2, it is judged whether or not the comparison of the spectrum powers for all the frequencies is completed. If so, the operation is ended, and if not so, the process proceeds to step m3. In step m3, the spectrum power Pi of the i-th frequency fi is read, and in step m4 the maximum value Pa up to that time and the spectrum power Pi of this time are compared, and the spectrum power P of this time is read.
When i is large, the maximum value Pa is updated to the spectrum power Pi of this time in step m5, and then the process proceeds to step m6. Otherwise, the process directly proceeds to step m6. In step m6, 1 is added to the count value i to update it, and then the process returns to step m2. In this way, the maximum value Pa of the spectrum power Pi is searched over the frequencies f0 to fn, and the searched maximum value Pa is set as the index value S of the observation period W1.

As described above, in the knocking control method according to the present invention, the output of the knock sensor 2 is used to detect the difference in the type of the internal combustion engine, such as the number of cylinders, the specification, and the vibration mode of the knocking. The knocking component can be accurately extracted and knocking determination can be performed, so that versatility can be improved and determination accuracy can be improved.

FIG. 4 is a diagram for explaining the operation of another embodiment of the present invention. In the above-described embodiment, a plurality of frequencies f0, f1, ..., F (i-1), obtained by frequency-analyzing the output from the knock sensor 2 within the observation period W1,
The spectrum power P of fi, f (i + 1), ..., Fn
Of 0, P1, ..., Pn, the maximum value is set to the index value S, whereas the maximum value in the remaining frequency band excluding the forbidden band indicated by reference numeral fb is set to the index value S. To be done. That is, the forbidden band fb is provided to prevent erroneous detection of valve opening / closing noise and the like indicated by the reference symbol PB as a knocking signal component, and improve knocking determination accuracy.

FIG. 5 is a flow chart for explaining the index value setting operation shown in FIG. This Figure 5
The operation indicated by is similar to the operation shown in FIG.
Corresponding parts are designated by the same reference numerals. It should be noted that
When data to be compared remains at step m2, at step m10, the i-th frequency f to be read next.
It is determined whether or not i is data within the forbidden band fb, and if so, the process directly moves to step m6,
Only when that is not right, it moves to step m3 and the spectrum power Pi is read.

With respect to the knocking determination standard V obtained on the basis of the index value S obtained in this way, the knocking determination is that any of the spectrum powers P0 to Pn of all frequencies f0 to fn is the knocking determination. It may be performed depending on whether or not it is equal to or higher than the reference V, or may be performed depending on whether or not the spectrum power of the frequency of the remaining band excluding the forbidden band fb is equal to or higher than the knocking determination reference V.

FIG. 6 is a diagram for explaining a knocking determination method according to still another embodiment of the present invention. In this embodiment, with respect to the analysis result of the observation period W1, a frequency that may include a signal component representing the occurrence of knocking, such as 7 kHz, 11 kHz, 13 kHz, 15 kHz, and 19 kHz, is mainly shown in FIG. , A plurality of frequency bands are set in advance and the maximum value Pa1 of the spectrum power in each frequency band F1, .. are compared with each other, and the maximum value (Pa2 in FIG. 6) is set as the index value S.

FIG. 7 is a flow chart for explaining the index value setting operation shown in FIG. 6 described above. This Figure 7
The operation indicated by is similar to the operation shown in FIG.
Corresponding parts are designated by the same reference numerals. It should be noted that
When data to be compared remains in step m2, it is determined in step m10a whether or not the i-th frequency fi to be read next is in the frequency band F in which knocking may occur. If not, the process proceeds to step m6, and if it is not, the process proceeds to step m3 to read the spectrum power Pi.

With respect to the knocking determination reference V created based on the index value S thus obtained, the knocking determination is based on the knocking determination reference V at all frequencies f0 to f.
It may be performed based on whether or not any of the spectrum powers P0 to Pn of n is exceeded, and is performed by comparing only the spectrum power in the frequency band F with the knocking determination reference V. Good.

FIG. 8 is a diagram for explaining the concept of a knocking determination method according to another embodiment of the present invention. In this embodiment, the spectrum power Pi of each frequency fi is analyzed as shown in FIG. 8 (2) for each observation period W1 with respect to the output from the knock sensor 2 shown in FIG. 8 (1). . From the analysis result, similar to the embodiment shown in FIG. 6 described above, the maximum value Pa of the spectrum power is generated for each frequency band F1, F2, ... In which knocking may occur.
1, Pa2 is calculated, and these maximum values Pa1, Pa2, ...
Are set to index values Sa1, Sa2, ..., respectively.

These index values Sa1, Sa2, ... Are frequency bands F1, F2, which correspond to each other in each observation period W1.
A moving average is obtained for each of the above-mentioned equations 1 and is used as knocking determination criteria V1, V2 ,. Any one of the knocking determination criteria V1, V2, ... Obtained in this way corresponds to the corresponding index value Sa1i, Sa2i ,.
When at least one of the above is exceeded, it is determined that knocking has occurred.

When obtaining the knocking determination reference V1 from the index values Sa1, Sa2, ... According to the equation 1, the index values Sa1, Sa2, ... May be weighted as shown in the equation 2.

V = [Sa1 (i-1) * α1 + Sa1 (i-2) * α2 + ... Sa1 (i-8) * α8] / 8 (2) That is, for example, α1 = 2, α2 = 1.6, α3 =
1.2, ..., From the last index value Sa1 (i-1) to the index value Sa1 (i-8) before 7 calculation cycles, weighting is performed so that the new index value has a greater influence. The moving average can be calculated.

As still another embodiment of the present invention, in FIG. 9, frequencies f (a-1) and f (a +) adjacent to the frequency fa at which the spectrum power has the maximum value Pa.
A value obtained by adding the spectrum power of 1) to the maximum value Pa may be set as the index value S. by this,
The actual maximum value indicated by reference sign Pb can be captured. That is, even if the maximum value of the actual spectrum power cannot be detected due to the resolution of the frequency analyzer 8, the maximum value is detected without omission from the sum of the spectrum power of the sampling frequencies adjacent to it. It becomes possible.

In this embodiment, the upper and lower two frequencies f (a-1) and f (a + 1) adjacent to the frequency fa are added, but as another embodiment of the present invention, the frequency band is further expanded. For example, the spectrum powers at the frequencies f (a-2) and f (a + 2) may be added together. Further, with respect to the knocking determination reference V obtained from these added values, the knocking determination may be performed only by the maximum value Pa of the spectrum power, or the frequency f (a adjacent to the frequency fa of the maximum value Pa is determined. Knocking determination may be performed by the added value obtained by adding the spectrum powers of −1) and f (a + 1).

Further, in this embodiment as well, the forbidden band fb may be set similarly to the above-mentioned embodiments, and a plurality of frequency bands F in which knocking may occur may occur.
1, F2, ... May be set. Further, the knocking determination may be performed based on the maximum value Pa as in the above, or based on the spectrum power at frequencies other than the forbidden band fb or frequencies within the frequency bands F1, F2, .... Good.

FIG. 10 is a diagram for explaining a knocking determination method according to another embodiment of the present invention. In this embodiment, as indicated by reference numerals Pb1, Pb2, ... (When collectively referred to as reference numeral Pb), spectrum powers P0, P1, P2 of, for example, three frequencies f0, f1, f2 adjacent to each other are provided. The added value Pb1 of
Spectrum power P1, P2, P at f2, f3
The added value Pb2 of 3 is set to the next frequency f2, f3, f
4 and so on, and their added values Pb1, Pb
The maximum value of 2, ... Is used as the index value S. Also in this case, similarly to the above, the knocking determination may be performed from the maximum value Pa of the spectrum power with respect to the knocking determination reference V obtained by using the added values Pb1, Pb2, ... As the index value S. Knocking determination may be performed from the added values Pb1 and Pb2. Furthermore, also in this embodiment, the forbidden band fb may be set, and frequency bands F1 and F where knocking may occur.
2, ... May be set.

Furthermore, in each of the above-described embodiments, the P0 to Pn maximum value Pa or the added value Pb of the spectrum power is set.
Although the index value S is set on the basis of the maximum value of, the spectrum powers P0 to Pn of all the frequencies f0 to fn
The added value of may be used as the index value.

Further, as shown in FIG. 11, the forbidden band f
It is also possible to set b and use the added value of the spectrum power over the remaining frequency band as the index value. Furthermore, as shown in FIG. 12, a plurality of frequency bands F1, F2, ... In which knocking may occur are set, and each frequency band F
1, F2, ... Calculates the added value of spectrum power,
The maximum value of the added values may be used as the index value, or the index value may be set for each frequency band F1, F2, ....

Furthermore, in each of the above-described embodiments, the knocking determination criterion V is the consecutive index values S (i-1), S (i
-2), ..., but as another embodiment of the present invention, for example, in the case of four cylinders, S (i-1), S
(I-5), S (i-9), ..., In the case of 6 cylinders, S (i-1), S (i-7), S (i-13) ,. Data may be collected for each cylinder. This makes it possible to deal with variations in the detection sensitivity of each cylinder of the knock sensor 2 due to a distance difference from the knock sensor 2 and the like, and it is possible to perform a highly accurate knocking determination.

[0059]

As described above, according to the present invention, it is possible to knock from the output of the knock sensor regardless of the difference in the type and specifications of the internal combustion engine, such as the number of cylinders, and the difference in the knocking vibration mode. It is possible to accurately extract the component and perform knocking determination, which improves versatility and improves determination accuracy.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electrical configuration of an ignition timing control device 1 for an internal combustion engine in which a knocking control method according to an embodiment of the present invention is used.

FIG. 2 is a diagram for explaining the basic idea of the knocking determination method of the present invention.

FIG. 3 is a diagram for explaining a specific method for obtaining an index value S in FIG.

FIG. 4 is a diagram for explaining a knocking determination method according to another embodiment of the present invention.

5 is a flowchart for explaining the index value setting operation shown in FIG.

FIG. 6 is a diagram for explaining a knocking determination method according to still another embodiment of the present invention.

FIG. 7 is a flowchart for explaining an index value setting operation in FIG.

FIG. 8 is a diagram for explaining the concept of a knocking determination method according to another embodiment of the present invention.

FIG. 9 is a diagram for explaining a knocking determination method according to still another embodiment of the present invention.

FIG. 10 is a diagram for explaining a knocking determination method according to another embodiment of the present invention.

FIG. 11 is a diagram for explaining a knocking determination method according to still another embodiment of the present invention.

FIG. 12 is a diagram for explaining a knocking determination method according to another embodiment of the present invention.

FIG. 13 is a diagram showing a relationship between a resonance mode of a cylinder block due to knocking and a resonance frequency.

[Explanation of symbols]

 1 Ignition Timing Control Device 2 Knock Sensor 5 Crank Angle Sensor 7 Sampling Signal Generation Circuit 8 Frequency Analyzer 9 Knocking Judgment Circuit 11 Control Circuit 12-14 Sensors S1, S2, ..., Sa1, Sa2, ... Index Value W1 Observation Period

Claims (11)

[Claims] 1. A knocking observation period is set at a predetermined timing between the top dead center of the piston in response to the output of the crank angle sensor, and a frequency analysis of the output of the knock sensor is performed during the observation period. From the spectrum distribution, set a value calculated based on the spectrum power over the observation period as an index value, perform knocking determination based on the index value, and control the ignition advance angle according to the determination result. A knocking control method characterized by: 2. A knocking observation period is set at a predetermined timing between the top dead center of the piston in response to the output of the crank angle sensor, and a frequency analysis of the output of the knock sensor is performed during the observation period. From the spectrum distribution, the frequency band that may contain the signal component that indicates the occurrence of knocking is preset over the observation period, and the value calculated based on the spectrum power in this frequency band is used as the index value. Set a knocking judgment standard based on the index value and perform knocking judgment based on whether or not the maximum value of the spectrum power at all frequencies is equal to or larger than this judgment standard. A knocking control method characterized by controlling a corner. 3. A knocking observation period is set at a predetermined timing between the top dead center of the piston in response to the output of the crank angle sensor, and the frequency of the knock sensor output is analyzed during the observation period. From the spectrum distribution, the frequency band that may contain the signal component that indicates the occurrence of knocking is preset over the observation period, and the value calculated based on the spectrum power in this frequency band is used as the index value. Set, and create a knocking criterion based on the index value, whether the maximum value of the spectrum power in the frequency band that may include a signal component representing the occurrence of knocking is more than this criterion. A knocking control method characterized by performing knocking determination from the front and controlling the ignition advance angle according to the determination result. Law. 4. A knocking observation period is set at a predetermined timing between the top dead centers of the pistons in response to the output of the crank angle sensor, and the frequency of the output of the knock sensor is analyzed during the observation period. From the spectrum distribution, over the observation period, preset a plurality of each frequency band that may contain a signal component representing the occurrence of knocking, a value calculated based on the spectrum power in each frequency band Is set as an index value, a knocking determination standard is created based on the index value, knocking determination is performed based on whether or not the maximum value of the spectrum power at all frequencies is equal to or greater than this determination standard, and the determination result is supported. And a knocking control method for controlling an ignition advance angle. 5. A knocking observation period is set at a predetermined timing between the top dead center of the piston in response to the output of the crank angle sensor, and a frequency analysis of the output of the knock sensor is performed during the observation period. From the spectrum distribution, over the observation period, preset a plurality of each frequency band that may contain a signal component representing the occurrence of knocking, a value calculated based on the spectrum power in each frequency band Is set as an index value, and a knocking determination standard is created based on the index value, and the maximum value of the spectrum power in each frequency band that may include a signal component representing the occurrence of the knocking is the determination standard. The knocking determination is made based on whether or not it is above, and the ignition advance angle is controlled according to the determination result. Locking control method. 6. A knocking observation period is set at a predetermined timing between the top dead center of the piston in response to the output of the crank angle sensor, and a frequency analysis of the output of the knock sensor is performed in the observation period. From the spectrum distribution, a plurality of frequency bands that may include a signal component representing the occurrence of knocking are preset over the observation period, and are calculated based on the spectrum power of each of the frequency bands. Value is set as an index value, a knocking determination standard is created for each of the frequency bands based on the index value, and whether at least one of the spectrum powers in the corresponding frequency band is equal to or greater than the determination standard. A knocking control method characterized by performing knocking determination from the front and controlling the ignition advance angle according to the determination result. 7. The knocking control method according to claim 1, wherein the index value is set to a maximum value of the spectrum power. 8. The index value is set to an addition value of spectrum powers of a frequency having the maximum spectrum power and a frequency adjacent to the frequency. The knocking control method described in 1. 9. The index value is set to a maximum value of a sum of spectrum powers of a plurality of frequencies representing a peak value of the spectrum power and a frequency adjacent to the frequency. Item 7. A knocking control method according to any one of items 1 to 6. 10. The knocking control method according to claim 1, wherein the index value is set to an addition value over the entire frequency band of the spectrum power. 11. A knock sensor for detecting knocking of an internal combustion engine, a crank angle sensor for detecting a rotation angle position of the internal combustion engine, and a top dead center of a piston of the internal combustion engine in response to an output of the crank angle sensor. Analyzing means for performing a frequency analysis of the output from the knock sensor in a knocking observation period set between predetermined timings, from the analysis result of the analyzing means, an index value setting means for obtaining an index value over the observation period, and A knocking control device, comprising: a control unit that performs knocking determination based on an index value and controls the ignition advance angle according to the determination result.