JPS63253173A - Knocking control device for engine - Google Patents

Abstract

PURPOSE:To enable a high accurate control of knocking to be attained, by obtaining the maximum value of detection signals from a knocking sensor by a predetermined number of times and setting a control amount of knocking being based on the statistical characteristic value of the maximum value. CONSTITUTION:A detection signal from a knocking sensor 4 is detected for its maximum value in a generation period of knocking, generated in the vicinity of at least the top dead center, by a predetermined number of times in a maximum value detecting means 5 being statistically processed in a characteristic value arithmetic means 6, and the statistical characteristic value of mean value, maximum times value, etc. is obtained. And a knocking control device, being based on this statistical characteristic values, sets a control amount of knocking of knocking decision level or the like in a control amount setting means 7, retarding, for instance, the ignition timing of a spark plug 3 to suppress generation of knocking, in the time of its generation, while advancing the ignition timing to improve a combustion condition, when no knocking is generated, by a combustion condition control means 2. In this way, a high accurate control of knocking can be performed by accurately catching a generation condition of knocking.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine knocking control device that controls ignition timing, etc. in response to the occurrence of engine knocking so as to eliminate this knocking. It is.

(Prior Art) Conventionally, as an engine knock control device, a technique is known that, when the occurrence of knocking is detected, controls Offi, which governs the ignition timing and other combustion conditions, to suppress the occurrence of knocking. In addition, for determining the occurrence of knocking, for example, Japanese Patent Application Laid-Open No. 58-28646
As seen in the issue, the average value of the knocking sensor output in a state where no knocking occurs is determined in advance, a certain knocking judgment level is set for each engine and each knocking sensor corresponding to this, and this judgment level is set. Some devices compare the output of the knocking sensor with the output of the knocking sensor, and determine that knocking has occurred when the sensor output exceeds a determination level.

(Problem to be Solved by the Invention) As described above, when detecting engine i+ by a knocking sensor and controlling the combustion state of the engine according to the knocking determination based on the detected value of this non-king sensor, When knocking is not occurring, the knocking sensor output detects noise caused by vibrations such as valve opening/closing sounds that occur regularly as the engine operates, and when knocking is occurring. The detection signal is output with knocking vibration superimposed on the background noise. If the knocking determination level is not set accurately between the two, the knocking detection viscosity will decrease, and the knocking control control tII accuracy will decrease.

However, the background noise and non-king signal described above vary depending on the individual engine and operating conditions such as aging, engine speed, and ambient temperature.
It changes depending on the detection error of each knocking sensor and changes over time.If the judgment level is set to a constant value as mentioned above, it will be possible to judge the noise as a knocking state or to detect a non-knocking state. It may not be possible to accurately determine the engine output, or the engine output may be unnecessarily suppressed, or the occurrence of knocking may not be suppressed, which may adversely affect the durability of the engine.

Therefore, in view of the above circumstances, the present invention provides an engine knocking control I device that accurately determines the state of occurrence of knocking from the detection signal of a knocking sensor and performs highly accurate knocking control without being affected by background noise, etc. The purpose is to provide

When the knocking sensor detects engine vibration and detects the maximum value Vp of vibration during the knocking period at least near the top dead center of the engine a predetermined number of times, the distribution characteristic in statistical processing is determined, for example, as shown in FIG. , the detection signal when no knocking occurs, that is, the background noise, has an approximately normal distribution as shown by the solid line, where the frequency of occurrence Mi with respect to the magnitude of the maximum value Vp is shown by the broken line when non-knocking occurs. It has been found that the frequency of occurrence in the high level region of the detection output increases and its distribution characteristics change, and the objective is to improve the accuracy of the control based on this characteristic.

(Means for Solving the Problems) The knock control til+ device of the present invention detects engine vibration with a knock sensor, and controls the combustion state of the engine in accordance with a knock determination based on the detected value of the knock sensor. Maximum value detection means for determining the maximum value of the detection signal of the knocking sensor a predetermined number of times during at least the knocking occurrence period during one engine cycle; Characteristic value calculation means for determining a statistical characteristic value such as the average value of the plurality of detected maximum values. , and control 1ffi setting means for setting the control gI amount of knocking control based on the characteristic value.

FIG. 1 is an overall configuration diagram for clearly showing the configuration of the present invention.

The engine 1 includes a combustion state control means 2 that suppresses knocking by controlling the combustion state of the spark plug 3 to change its combustion state, for example, by controlling the ignition timing of the spark plug 3. The above-mentioned combustion state side 61] means 2 controls the ignition timing, as well as the air-fuel ratio side,
It may be configured by control means such as EGR control and knocking suppressant supply control.

Further, a knocking sensor 4 for detecting engine vibration is installed in the engine 1, and its detection signal is outputted to a maximum value detection means 5. The maximum value detection means 5 is for determining the maximum value of the detection signal of the knocking sensor 4 at least a predetermined number of times during a knocking occurrence period near the top dead center. The maximum value obtained a predetermined number of times by the maximum value detection means 5 is outputted to the characteristic value calculation means 6, and the plurality of detected maximum values are statistically processed to obtain statistical characteristic values such as an average value and a maximum degree numerical value. This statistical characteristic value is output to the control amount setting means 7, and this control 611 setting means 7 sets the control amount for knocking control such as the knock judgment level based on the statistical characteristic value.
A signal is output to the combustion state control means 2 to shift the combustion state in the direction of suppressing knocking by, for example, retarding the ignition timing when knocking occurs, and advancing the ignition timing, for example, when knocking is not occurring. Knocking control is performed to output a signal to shift to a combustion state that is preferable in terms of engine output, etc.

(Function) Knocking system as described above tl]B[l! Now, the maximum value of the detection signal of the knocking sensor that detects engine vibration is determined a predetermined number of times, a statistical characteristic value such as the average value of the plurality of detected maximum values is determined, and the knocking control is controlled based on this statistical characteristic value. Even if the background noise and knocking signal change depending on the error of individual knocking sensors, individual engine or operating conditions, aging, etc., the noise will be approximately normally distributed. Therefore, since the characteristics of the knocking signal that occurs on the high level side do not change, the control amount of knocking control is set for the statistical characteristic value that changes in response to changes in the normal distribution characteristics, and the knocking occurrence state is determined. The engine is designed to accurately detect this and perform highly accurate knocking control accordingly.

(Example) Hereinafter, each embodiment of the present invention will be described in detail along with the drawings.

Embodiment 1 FIG. 3 is an overall configuration diagram of a specific example. This embodiment shows an example in which knocking control is performed by controlling the ignition timing of the engine.

A spark plug 3 is disposed facing the combustion chamber 11 of the cylinder of the engine 1, and the spark plug 3 has a distributor 1.
A discharge voltage from an ignition coil 13 is applied through the ignition coil 13, and an ignition signal from a control unit 14 is output to the ignition coil 13 to adjust and control the ignition timing.

On the other hand, an intake passage 17 that supplies intake air to the combustion chamber 11 of the engine 1 in response to opening and closing of the intake valve 16 includes an intake air amount sensor 18 that detects the intake air amount from the upstream side, and a throttle valve 19 that controls the intake air amount. , an injector 20 are installed in this order. Furthermore, the exhaust gas from the combustion chamber 11 is removed from the exhaust valve 21.
A catalyst device 23 is interposed in the exhaust passage 22 which is discharged by opening and closing. Further, the engine 1 is provided with a knocking sensor 4 that detects engine vibration, and the distributor 12 is further provided with a first crank angle sensor 25 that outputs a signal at a predetermined crank angle (60 to 90 degrees after top dead center). and other predetermined crank angles (30~ before top dead center)
A second crank angle sensor 26 that outputs a signal at 0°) is installed, and detection signals from these various sensors are input to the control unit 14.

Then, the control unit 14 performs basic ignition timing setting based on the engine speed and load (filling amount) in accordance with detection signals from various sensors, and also sets the knocking sensor 4 based on the knock judgment level based on the learned value. The feedback correction value is set so that the ignition timing is retarded to suppress the occurrence of knocking when non-king occurs, and the ignition timing is gradually advanced when knocking is not occurring. Performs feedback control.

In addition, the maximum value (peak voltage) of the knock sensor 4 output during the knocking period near top dead center is input a predetermined number of times, the average value is obtained, and this average value is multiplied by a predetermined coefficient to obtain the learned value of the knock judgment level. control to update. In setting the actual ignition timing, the final ignition timing is set based on the basic ignition timing and the feedback correction value, and an ignition signal is output at this ignition timing to perform ignition timing control.

FIG. 4 shows the internal structure of the control unit 14, which includes a CPU 28, a ROM 29 that stores calculation programs, a RAM 30 that stores learning values, etc., a free running counter 31, a CP
Three PTM32-3 whose time is set by U28
4 (program timer), and the first and second crank angle sensors 25 .
26 crank angle signals are input as interrupt signals,
Furthermore, an intake air amount signal from the intake air amount sensor 18 and a detection signal from the knocking sensor 4 are inputted via an analog buffer 36 and an A/D converter 37 .

The detection signal of the knocking sensor 4 is processed by the knock detection circuit 38 (details shown in FIG. 5) of the analog buffer 136 using the gate signal GA from the first and second PTMs 32, 33 and the knock judgment from the D/A converter 39. Level signal Vre, reset signal R1 from output boat 4o
, Rz and the gain control signals Gl, G2, and the maximum value signal Vp between knocking occurrence wJ
(peak voltage) and the knock intensity signal 1k as a comparison result with the judgment level (<integrated voltage) is determined by the CPU 28.
is input. Further, the ignition timing as a calculation result of the CPLI 28 is set in the third PTM 34 and activated by the trigger signal of the first crank angle sensor 25.
The output signal is outputted to the ignition coil 13 as an ignition signal via an output interface 41.

As shown in FIG. 5, the knock detection circuit 38 has a BPF 45 (band pass filter) which receives a signal from the knock sensor 4 and extracts a knocking frequency component, and this signal is amplified by an input AMP 46. By opening and closing the gate of the analog switch 47 in response to the gate signal GA, only the signal during the knocking photogeneration period (10 to 50 degrees after top dead center) is inputted to the peak hold circuit 48 and the comparator 49.

The peak hold circuit 48 obtains the maximum value Vp by holding the peak value during the gate open period, and is reset by the reset signal R1. On the other hand, the knock determination level signal Vre is input to the comparator 49, and a signal with a higher level than this determination level is input to the integrator 50, which calculates the integral value 1k (knock intensity signal) of the gate open period, and outputs the reset signal R.
It is reset by z.

In addition, since the output of the knocking sensor 4 changes depending on the engine speed, a gain adjusting resistor arranged in parallel is applied to the output of the input AMP 46 so as to keep the output of the input AMP 46 within a predetermined range. Gain control @ No. Gs to open and close analog switch 51.52,
G2 is input in accordance with the engine speed, and the gain of the input AMP 46 is adjusted by opening and closing analog switches 51 and 52.

The operation of the control unit 14 will be explained based on the flowcharts shown in FIGS. 6 to 8. FIG. 6 shows the main routine. After starting, initialization is performed in step S1, and based on the crank angle signal, the engine rotation speed Ne is calculated from the TDC cycle To.
Read the intake air ff1Qa from the output (G3). Then, in step S4, charge 1gff1Ce corresponding to the load is calculated from the engine speed NO and intake air amount Qa, and in step S5, engine speed Ne and charge 1affi are calculated.
The basic ignition timing Ab is calculated from the basic map with Ce.

In step $6, it is determined whether the operating state is in the knock zone or not based on the value of the filling amount Ce. If YES in the knock zone, the knock control flag Fk is set to 1 in step S7, and then the engine rotation speed is set to NO. and the current learning zone Zj from the zone map of the filling fitce
Find k (G8).

Then, in step S9, a learning value Ljk is read from the learning map corresponding to this current learning zone Zjk, and in step 810, this learning value Ljk is converted into a voltage Vre as a knock determination level and output to the D/A converter 39.

The above zone map shows engine speed Ne and charging ff1c.
e is divided into sections and set into vertical and horizontal zones Zjk, and the learning map stores the learning value Ljk of the knock judgment level in each zone corresponding to the zone map as shown in FIG.

Then, in step 811, the filling amount change rate Qc for acceleration detection is calculated from the difference between the current filling IWfflce and the previous filling amount Cb, and the previous filling ff1ctl is updated (S12).
In step 813, the charge Ia suspension change rate [)C is set to a predetermined value D.
It is determined whether the acceleration is greater than CO or not. This step 81
If the determination in step 3 is YES and acceleration is occurring, the maximum average number of times Na is set to a small value (30 times) in step 814 to increase responsiveness, whereas if the determination is NO and acceleration is not occurring, step 8
15, the maximum average number of times Na is set to a large value (100 times) to improve the stability of 1lilJ control.

Steps 816 to 820 are for adjusting the gain of the input AMP 46 according to the engine rotation speed N (3). In step 816, it is determined whether the engine rotation speed Ne is in a high rotation range of 4500 rpm+ or more, and in step 81
In step 7, it is determined whether the engine rotation speed Ne is in a medium rotation range of 2000 rpm or more. This step 816. As a result of the determination in S17, if the rotation is in the high rotation range, input A is input in step 318.
Both gate signals @Gt so that the gain of MP46 is small
, set G2 to high level and analog switch 51.52
is closed, and in the case of medium rotation range, the input AM is input in step 819.
One gate signal G1 so that the gain of P46 becomes an intermediate value.
is set to high level, one analog switch 51 is closed, and if the rotation speed is low, the input A is set to high level in step 820.
Both gate signals @G1. so that the gain of MP46 becomes a large value.
This is to set Gz to low level and open analog switches 51 and 52.

If the determination in step S6 is No and the knock zone is not present, the process proceeds to step 821 and the knock control flag "k" is cleared to O.

Next, FIG. 7 shows an interwoven routine, which starts with a signal input every 60'' after top dead center, reads interrupt time T1 from the free running counter 31 in step 822, and starts cranking from the previous time Tz. Calculate the TDC period To in which the angle rotates 180° and find <3
23>, update the previous vl loading time T2 (824
>.

Step 825 is for determining whether or not the knock control flag Fk of the main routine is in the knock zone. If YES in the knock zone, step 825 is performed.
At step 6, the knock intensity 1k is read from the knock detection circuit 38, and at step 827, a low level reset signal R2 is output to the integrator 50 so as to reset the knock intensity 1k. On the other hand, when it is determined No in step 825 that the knock zone is not in the knock zone, the feedback correction value Af is determined in step 828.
Clear b to 0.

Step 329 determines whether or not knocking has occurred depending on whether or not knocking intensity 1 is detected. If YES that knocking has occurred, step 830 retards the feedback correction value Afb according to knock intensity 1k ( Cr is a coefficient). On the other hand, if the determination in step 829 is No and knocking has not occurred, the process proceeds to step S31 and the feedback correction value Afb is advanced by a predetermined value.

After correcting the feedback correction value Afb as described above, in step 832, the maximum value VD (peak voltage) is input from the peak hold circuit 48, and this maximum value Vp
833). Then, in step 834, the cumulative value yt of the maximum value Vp is obtained, and the number of additions NC is calculated (S35).

Next, in step 836, it is determined whether learning is completed or not by adding the number of times Nc
The determination is made based on whether or not the value has reached the predetermined value Na (30 or 100). If the determination is YES, the determination level creation magnification Cj corresponding to the current learning zone Zjk is read from the map in step 337. As shown in FIG. 10, the map in which the above-mentioned magnification Cj is set has a value that becomes smaller as the engine speed increases, in each zone divided by the engine speed Ne and the filling ff1ce corresponding to the classification of the learning map. However, the magnification Cj is set in advance so that it increases as the filling amount increases. In other words, this magnification Cj is used to find a level corresponding to the noise distribution width from the average value, and the higher the engine rotation speed Ne, the narrower the distribution width, and the higher the engine speed, the wider the distribution width. It is set accordingly.

Then, the average value of the maximum value Vp (cumulative value Vt/number of additions N
c> and the magnification Cj, the learning value Ljk of the current learning zone Zjk is updated in step 838, and the learning register Nc
, Vt is cleared (839).

This learning value Ljk is updated by 5% of the average value Vt/NC.
is multiplied by a magnification (1+Cj) and added to 95% of the previous learned value to avoid sudden fluctuations.

Based on the basic ignition timing Ab and the feedback correction value Afb obtained as described above, the final ignition timing AsC (top dead center curve advance angle) is calculated in step S40.
In step 41, the time Tc (energization time) from 90 degrees before top dead center when the signal of the first crank angle sensor 25 becomes low level until the final ignition timing As is reached is calculated, and this power supply time TC is set to the third PTM 34. 842), the crank angle signal at 90' before top dead center is used as a trigger to set the 3rd P.
TM34 is activated and is controlled to output an ignition signal after a set time TC.

FIG. 8 shows the second interwoven routine, which starts every 30 degrees before top dead center. This is for setting and outputting a gate signal GA to the analog switch 47 of the knock detection circuit 38. That is, in step 843, the time TgO until the analog switch 47 opens at 10 degrees from the top dead center is calculated, and the opening time T (IC) until the analog switch 47 closes at 50'' after the top dead center is calculated. <844).Then, in step 845, the above time T
Go.

Output TCIC to the first and second PTM32.33,
After top dead center, time T (analog switch 47 when IQ elapses)
After the time Tqc has elapsed, the analog switch 47 is closed and the intake valve closing sound is peak-holded by the circuit 4.
8 and the comparator 49 so as not to allow input. Also, at the same time as setting the time to PTM32.33 above,
High-level reset signals R2 and Rt are output to the integrator 50 and the peak hold circuit 48, which have been reset in steps 827 and 833, to enable them to operate (846 and 847).

In the embodiment described above, the maximum value V in a predetermined period during which knocking occurs from the detection signal of the knocking sensor 4.
p is obtained, and the maximum value Vp detected a predetermined number of times is statistically processed to obtain an average value, and this average value approximately corresponds to the center position of the normal distribution of background noise, and is preset for the engine rotation speed and filling amount. The knock judgment level obtained by multiplying by the multiplication factor Cj is stored in the academic Akane map, read out according to the operating state, and outputted to the comparator 49 to be compared with the output of the knocking sensor 4. When knocking occurs, the high level signal increases. Accordingly, the comparator 49 provides an output to the integrator 50 in accordance with the magnitude of knocking, and feedback control of the ignition timing is performed in accordance with this signal to control the occurrence of knocking to approximately the knocking occurrence limit.

Embodiment 2 In this embodiment, the maximum value Vp from the knocking sensor 4 is detected a plurality of times, and the maximum value Vp in the distribution characteristic of the frequency of occurrence with respect to the magnitude of the maximum value Vp is determined by statistical processing.
1 is calculated, and the knock determination level is set based on the distribution width on the low level side from this maximum degree value. Its basic configuration is the same as that of the previous example, and the processing of the control unit 14 will be explained based on the flowcharts of FIGS. 11 to 13. In this flowchart, gain adjustment of the input AMP 46, gate control for the analog switch 47 for setting the detection period, etc. are omitted. In this example, the knock detection circuit 38 does not include a comparator 49 and an integrator 50, and the maximum value Vp
The system is designed to detect the occurrence of knocking.

FIG. 11 shows the main routine. After starting and initializing (849), intake air ff1Qa is read (35
0), the basic ignition timing Ab (ignition advance angle) is determined from this intake air ff1Qa and engine speed NO (35
1). Then, in step 852, it is determined whether or not the full affiCe is in the knock zone of a predetermined value of 080 or more, and if this determination is YES and it is in the knock zone, step 3
In step 53, the knock control flag Fk is set to 1, and the operating zone 2jk is determined based on the filling amount Ce and the engine speed Ne (354). On the other hand, if the determination in step S52 is No and the knock zone is non-knock, the knock control flag Fk is cleared to O in step 855.

FIG. 12 shows an interrelated routine, in which after an interrupt start, in step 856, the engine rotation speed Ne is calculated from the interrupt period TO, and the next ignition cylinder number is set to the cylinder flag Fc based on the cylinder identification signal from the cylinder sensor, etc.
Set to y (857). Then, in step 858, the knock zone is determined based on whether or not the knock control flag l''k is set to 1, and if YES in the knock zone, the basic ignition timing Ab is determined in step 359 using the feedback obtained by the interlaced routine described below. While the final ignition timing AS is obtained by correcting the knock retardation using the correction value Afb, the N in the non-knock zone.

Sometimes, in step 860, the final ignition timing AS is determined from the basic ignition timing Ab without performing feedback correction (knock retardation correction). Further, this final ignition timing As is converted into ignition time and the ignition is set for the two M34s (861), and the peak bold reset is canceled in step 862.

Furthermore, FIG. 13 shows a second interwoven routine, in which after the interrupt is started, the maximum value Vp of the knocking occurrence period of the knocking sensor 4 output is read in step S63. In step 864, the knock zone is determined by whether or not the knock control flag Fk is set to 1, and if YES in the knock zone, it is determined whether the current driving zone Zjk is in the learned state (365), When the answer is YES, the knock judgment level Ljk of the current cylinder number Fcy is read out from the learning map in step 866. On the other hand, when the judgment is NO in an unlearned state, the knock judgment level Ljk of the current cylinder number Fcy is read out from the learning map.
67 is the knock judgment level Ljk of the current cylinder number Fcy.
is read from the initial value map.

Then, in step 868, it is determined whether the maximum value Vp is greater than the knock determination level Ljk, and this determination is YES.
When knocking occurs in step S69, the feedback correction value Afb is set to the knock determination level Ljk8. fIl
The retard angle is corrected by adding a value obtained by multiplying the obtained maximum ravρ by a predetermined coefficient α, and in step 870, it is determined whether the feedback correction value Afb calculated above is less than or equal to the upper limit value A nax. regulates the feedback correction value Afb to this upper limit (lfiAnax (8
71). If the determination in step 868 is NO and knocking has not occurred, then in step 872 the lead angle is corrected by subtracting a predetermined value Aad from the feedback correction value Afb, and in step 873 the feedback correction value Afb calculated above is set to the lower limit value 0. It is determined whether or not the above is true, and in the following cases, the feedback correction value Afb is regulated to O (874
).

Step 875 is to determine whether the current operation zone Zjk is the same zone as the previous one. If YES, which indicates that the current operating zone Zjk is in a steady state in the same zone, in step 876, the distribution calculation memory is stored in order to calculate the distribution of the maximum value Vp. The memory value Mi of number i corresponding to the output level of the current maximum value Vρ inputted to is incremented, the frequency of occurrence of the corresponding output level is determined, and the total number of additions NC is calculated (<877').

Next, in step 878, it is determined whether learning is completed or not based on whether the number of additions Nc has reached a predetermined value No. If this determination is YES, in step 879, the maximum value Vpn at the maximum point MIN of the occurrence frequency Mi is determined. Search from the memory for the distribution meter sieve. This search, for example, sequentially compares the memory values Mi, sequentially updates the memory number with the largest memory value,
Compare all memory values and find the final maximum memory value fvll
The output level corresponding to the memory number of
That is.

Then, based on the maximum degree value Vpl obtained by the above search, in step S80, the distribution on the lower level side than the maximum degree value vpn+ in the maximum value distribution (see FIG. 14) is shifted to the higher level side with this maximum degree value Vpn as the center. The standard deviation σ of the symmetrically folded distribution, that is, the background noise distribution is determined, and in step 381, the knock determination level l jki is calculated for each cylinder. This knock judgment level l
jki is calculated by multiplying the standard deviation σ by the cylinder coefficient Ki and adding it to the maximum degree value Vpl.

Knock judgment level 1j for each cylinder determined as above
In step S82, ki is entered into a predetermined zone Zjk of the knock determination level learning map for each cylinder to update the learning value. Then, a register Mi for distribution calculation,
Clear the NC (883), update the previous zone Zjk (884), and reset the peak hold circuit 18 in step 885.

Also, in the middle of the transition to the non-knock zone, stencil 864
When the determination in step 375 is No, or even if the driving zone is in the knock zone, the driving zone changes and the determination in step 375 is No.
If so, the process advances to step 883 and learning of the knock determination level is stopped.

In this embodiment, as a statistical characteristic value of the maximum value Vp from the knocking sensor 4, a maximum degree value Vpm which is almost unaffected by the occurrence of non-king is obtained, and a knock judgment is made in accordance with this maximum degree value VpIl. By setting the level Ljk for each cylinder, the knocking detection accuracy is further improved, and the knocking control accuracy is also increased.

Embodiment 3 In this embodiment, the maximum value Vρ from the knocking sensor 4 is detected a plurality of times, and the average value of the maximum value Vp and the maximum frequency MID in the distribution characteristic of the benshi frequency are determined by statistical processing. This is an example in which the knock determination level Ljk is set based on the knock determination level Ljk, and its basic configuration is the same as the previous example, and the processing of the control unit 14 will be explained based on the flowcharts of FIGS. 15 to 17.

FIG. 15 shows the main routine. After starting and initialization (S'100), the learning value reflection permission flag Fre for the knock determination level is set to 1 in step 5101.

This reflection permission flag Fre is set to the learned value Ljk when learning is performed for the first time after the engine starts vJ in a certain school zone Zjk.
This is to reflect the change in other learning zones only once when the change exceeds a predetermined value.

In step 8102, intake air ff1Qa is read, and basic ignition timing Ab is calculated from this intake air mQa and engine speed Ne (8103). And step 51
In step 04, it is determined whether or not the filling ff1ce is in the knock zone of a predetermined value 000 or more. If the determination is YES and it is in the knock zone, the knock control flag Fk is set to 1 in step 5105, and the filling ff1ce is set to 1.
An operating zone Zjk is calculated from ce and engine speed NO (8106).

On the other hand, if the determination in step 8104 is No and the knock zone is non-knock, the knock control flag Fk is cleared to O in step 5107.

FIG. 16 shows an interwoven routine in which after an interrupt start, in step 3108, the engine rotation speed Ne is calculated from the J-in period TO, and in step 5109, the knock zone is determined to determine whether the knock control flag Fk is set to 1 or not. Y in the knock zone.
In the case of ES, the basic ignition timing Ab is corrected in step 5110 using the feedback correction value Afb obtained by the interrelated routine described later to obtain the final ignition timing As, while in the case of N0 in the non-knock zone, step 5111 is carried out.
The final ignition timing As is determined from the basic ignition timing Ab without feedback correction. This final ignition timing AS
Set the ignition based on the value of 8112), step 5
In step 113, the peak hold reset is canceled.

Furthermore, FIG. 17 shows a second interwoven routine, in which after the interrupt is started, the maximum value Vp of the knocking occurrence period of the knocking sensor 4 output is read in step 5114. In step 5115, the knock zone is determined by whether or not the knock control flag l''kl is set, and if YES in the knock zone, it is determined whether the current driving zone Zjk is in a learned state (116);
When the answer is YES in the learned state, the knock judgment level Ljk of the current driving zone Zjk is read from the learning map in step 5117. On the other hand, when the judgment is No in the unlearned state, the knock judgment level Ljk of the current driving zone Zjk is set to the initial value in step 8118. Read from map.

Then, in step 5119, it is determined whether the maximum value VD is greater than the knock determination level Ljk, and this determination is YE.
When knocking occurs in S, the feedback correction value Afi+ is corrected in step 5120 by a value obtained by multiplying the magnitude of the maximum value Vp at the knock judgment level and beyond the forest by a predetermined coefficient α, and in step 5121 the above-mentioned The calculated feedback correction fIiAfb is the upper limit A l1a
It is determined whether it is less than or equal to x, and if it exceeds, the feedback correction value Afb is regulated to the upper limit value AIIaX (8
122). If the determination in step 5119 is No and knocking has not occurred, then in step 5123 the feedback correction value Afb is reduced by a predetermined value Aad to advance the angle f, and in step 5124 the feedback correction value Afb based on the above calculation is corrected. It is determined whether or not the lower limit value is 0 or more, and in the following cases, the feedback correction value Afb is set to O (8125>).

Step 8126 is for determining whether or not the current operating zone Zjk is the same zone as the previous time. If YES in the same zone and in a steady state, step $127 is performed to determine if the difference between the detected maximum value Vρ and the judgment level Ljk is a predetermined value 3kn. Determine whether or not the value is greater than or equal to the value. This determination is performed in order to exclude the detected maximum value Vp from the average calculation when it is larger than a predetermined value, thereby reducing an error in the knock determination level due to excessive knocking or noise.

If the determination in step 5127 is NO, then in step 8128, in order to calculate the distribution of the maximum value Vp, the number i corresponding to the output level of the current maximum value Vp is stored in the memory for division 5 totals, etc. The memory value M1 is incremented to determine the frequency of occurrence of the corresponding output level, and step 8129
Calculate the total number of cylinders NC.

Next, in step 5130, it is determined whether or not the character shape is completed by counting the number of cylinders NC.
The determination is made based on whether or not the maximum value Vp has reached a predetermined value No. If the determination is YES, the maximum value Vp is
The average value AVp of is calculated from the maximum value ■cumulative sum of p.

Further, in step 5132, the maximum frequency Mm is obtained from the memory Mi of the frequency of occurrence, and the magnification K for calculating the knock determination level is calculated according to the value Ml11. This magnification has a tendency that the larger the maximum frequency Mlll is, the more concentrated the minute ti is, and the smaller its dispersion (standard ? 9; deviation).
It is set so that the larger the maximum frequency Ml11 is, the smaller the value becomes. Then, in step 5133, the average value AV
A knock determination level Ljk is calculated using p and the magnification K.

That is, as shown in FIG. 18, as the maximum frequency Mm, which approximately corresponds to the average value AVp, increases, the dispersion (distribution width) becomes narrower, while as the maximum frequency Mum decreases, the dispersion (distribution width) widens; By setting a relationship in which the magnification K is inversely proportional to the maximum frequency MIn, and multiplying the average value AVp by this magnification K, the knock determination level Ljk is set in accordance with the distribution characteristics.

Next, steps 8134 to 5139 are for reflecting the initial learned value to other zones, and in step 5134 it is determined whether the current driving zone Zjk is a pre-written type, and if YES for already learned, the learned value is reflected. It is determined whether the flag Fre is set to 1 (5135), and if it is set to YES, the determination level Ljk obtained this time and the determination level L stored in the learning map are determined in step 8136.
It is determined whether the ratio of L jkll is equal to or greater than a predetermined value Ra, and in step 5137, the ratio L jk / L jk is determined.
It is determined whether or not l is less than or equal to a predetermined value Rb, and if both determinations are YES, that is, if there has been a large change up or down beyond the range of the predetermined values Ra and Rb, all learning determinations other than the current driving zone are performed in step 8138. Level l jlv to above ratio L jk
/ L jlun is reflected and corrected as a coefficient, the reflection permission flag Fre is cleared (8139), and the process of reflecting the initial learning value to other zones is completed.

In step 5140, the knock determination level jk obtained as described above is entered into a predetermined zone Zjk of the knock determination level learning map for each cylinder to update the learned value. And registers Mi, Nc for the distribution PiAm
8141), the previous zone Zjk is updated (8142), and the peak hold circuit 48 is reset in step 5143.

In this embodiment, the average value AVp and the maximum frequency M1 are obtained as statistical characteristic values of the maximum value Vp of the knocking sensor 4/]-, and the average value AVp is The knock determination level Ljk is set by setting the magnification K of , thereby further improving the knocking detection accuracy and increasing the viscosity of the knocking control.

(Effects of the Invention) According to the present invention as described above, the maximum value of the detection signal of the knocking sensor that detects engine vibration is determined a predetermined number of times,
Through statistical processing of the plurality of detected maximum values, statistical characteristic values such as the average value, maximum degree value, maximum degree, etc. are obtained, and knocking control is performed by setting the knocking control control 11ffi based on the statistical characteristic values. By doing this, even if background noise and knocking signals change due to errors in individual knocking sensors, individual engine or operating conditions, changes over time, etc., knocking control can be adjusted based on the statistical characteristic values. The control 61ffi fluctuates, and the R1 state of knocking can be accurately captured to perform highly accurate knocking control.

[Brief explanation of drawings]

Fig. 1 is an overall configuration diagram to clarify the structure of the present invention, Fig. 2 is an explanatory diagram showing an example of the maximum value distribution 'v'f surname obtained from the detection signal of the non-king sensor, and Figs. 1st
Figure 0 shows the first embodiment of the present invention, Figure 3 is an overall configuration diagram, Figure 4 is a block diagram showing the internal configuration of the controller 1 to the roll unit, Figure 5 is a block diagram of the knock detection circuit, and Figure 5 is a block diagram of the knock detection circuit. Figure 6 is a flowchart showing the main routine, Figures 7 and 8 are flowcharts showing the interwoven routine, Figure 9 is a map showing an example of learning map settings, and Figure 10 is the magnification for creating a knock judgment level. FIG. 14 is an explanatory diagram illustrating the setting characteristics of the judgment level for the distribution characteristics in the second embodiment, and FIGS.
FIG. 7 is a flowchart in the third embodiment of the present invention, and FIG. 18 is an explanatory diagram illustrating the determination level setting characteristic for the distribution characteristic in the third embodiment. 1... Engine, 2... Combustion state control means, 4... Knocking sensor, 5...
・Maximum value detection means, 6...Characteristic value operating means, 7
... Control 611 Hanging setting means, 14 ... Control unit, 38 ... Knock detection circuit, 47 ... Analog switch, 48 ...
・Peak hold circuit. Figure 1 Figure 2 Figure 1 B-vρ (signed sword..., shi) Figure 9 Figure 10 Bad smell Ce

Claims (1)

[Claims] (1) An engine knocking control device that detects engine vibration with a knocking sensor and controls the combustion state of the engine according to a knocking determination based on the detected value of the knocking sensor, which maximum value detection means for determining the maximum value of the detection signal of the knocking sensor during the occurrence period a predetermined number of times; characteristic value calculation means for determining a statistical characteristic value such as the average value of the plurality of detected maximum values; 1. A knocking control device for an engine, comprising: control amount setting means for setting a control amount for knocking control.