JPH0646022B2 - Knotting control method for internal combustion engine - Google Patents

Description

The present invention relates to a knocking control method for an internal combustion engine, and particularly to a comparison between a corrected retard amount for performing a retard angle at a relatively high speed depending on the presence or absence of knocking and the presence or absence of knocking. The present invention relates to a method of correcting the basic ignition advance angle and controlling the knocking by performing the retard advance at a relatively slow speed and using the learning retard amount changed by the learning control.

The conventional learning control method is a knocking control method in which the engine speed N, the ratio Q / N of the intake air amount Q and the engine speed N
Alternatively, the basic ignition advance angle θ _BASE, which is determined in advance by the load determined by the intake pipe negative pressure, is stored in the form of a map in the lead-on memory (ROM) of the microcomputer.
Ignition advance angle θ that actually controls the igniter based on equation (1)
_ig is calculated, and knocking control is performed using this ignition advance angle.

θ _ig = θ _BASE − (θ _KG + θ _K ) …… (1) However, θ _KG is determined by the engine speed and load in order to set the knocking level to a predetermined level, and by learning control. The changed learning retard amount, θ _K, is a corrected retard amount that retards the ignition timing when knocking occurs and advances the ignition timing when knocking does not occur.

Here, the correction delay angle amount θ _K is obtained as follows.
First, the engine vibration is detected using a knocking sensor composed of a microphone, etc., and a predetermined multiple K · b (where K is a proportional constant) of the average value (back ground) of the engine vibration and the peak value of the engine vibration. Then, the peak value a is compared with the value of K · b. When the peak value a exceeds the value of K / b, it is judged that knocking has occurred and the following (2)
As shown in the equation, the correction retard angle amount θ _K is changed so that the ignition timing is delayed by a predetermined crank angle (for example, 0.4 ° CA) per occurrence of knocking.

θ _K ← θ _K + 0.4 ° CA ………… (2) When the peak value a is less than the value of K · b, it is judged that no knocking has occurred, and the first timer is used. It is determined whether or not a time (for example, 48 msec) has elapsed, and when a predetermined time has elapsed, a corrected crank angle (for example, 0.08 ° CA) correction retard amount is set so that the ignition timing advances as shown in the following equation (3). Change θ _K.

θ _K ← θ _K −0.08 ° CA (3) Further, the learning retard angle amount θ _KG according to the engine condition is calculated as follows. First, as shown in FIG. 1, the learning map is prepared by providing the addresses 0 to 23 for storing the learning retardation amount corresponding to the engine speed N and the load Q / N in the random access memory (RAM) of the microcomputer. Is created. A point (N, Q) indicating the current engine condition on the learning map by taking in the engine speed N and the intake air amount Q.
/ N) to find the addresses of the four RAMs surrounding it. Now, as shown in FIG. 2, a RAM surrounding a point indicating the current engine condition.
Address is n (n = 0, 1 ... 16), n + 1, n + 6,
n + 7, the learning retard angle θ _{KGN at} the address n, and the address n + 1
To the learning delay angle θ _{KG (n + 1)} , and at address n + 6 the learning delay angle θ _{KG (n + 1)}
It is assumed that the learning retard amount θ _{KG (n + 7)} is stored in the address _{KG (n + 6)} and the address n + 7. Then, the difference in engine speed between the addresses is X, the difference in load between the addresses is Y, the difference in engine speed between the address n and the point indicating the current engine condition is x, and the difference between the address n and the current engine is x. Assuming that the load difference between the point indicating the condition is y, the learning delay amount θ _{KG at the} point indicating the current engine state by the two-dimensional interpolation method shown in the following equations (4) to (6).
Is required.

Thus, the corrected retard angle θ changed as described above
_K and the learning retard angle amount θ _KG obtained by the two-dimensional interpolation method from the learning map to be learning-controlled, the basic ignition advance angle θ _BASE is interpolated based on the equation (1) to control the knocking. Of.

By the way, as shown in FIG. 3, the basic ignition advance θ _BASE, that is, MBT (Minimum Spark Advance For Best Torgu
e) changes like the curve C ₁ according to the engine speed. In addition, the minute knocking occurrence ignition timing when the knocking is difficult to occur, such as when the air is moist, is the curve C.
₂ , the minute knocking occurrence ignition timing when the knocking is likely to occur, such as when the air is dry, becomes like the curve C ₃ . Therefore, the minute knocking occurrence ignition timing varies depending on the engine speed and the annular condition.

In the notching control method by learning control as described above,
When the predetermined time has elapsed, all of the learning retard amount was independently changed to the advancing side by the learning control regardless of the presence or absence of knocking. There was a problem that the amount was too advanced and knocking occurred. Further, as described above, the learning retard amount tends to be learned and controlled toward the advance side, so that the learning control speed for controlling the ignition timing toward the advance side cannot be set fast, and the above-mentioned FIG. When the engine conditions, etc. change and it is difficult for knocking to occur, the ignition timing may be retarded too much due to the learning retard amount, and the best torque cannot be obtained in the region where knocking does not occur. There was a problem.

In order to deal with the above problem, the engine operation status is divided,
The learning control method that performs learning for each section is
It is proposed in JP-A-56-23566.

However, according to the method of the same publication, the retard amount of the ignition timing is increased when the knocking occurs, the retard amount is decreased when the knocking does not occur for a predetermined period, and the retard amount is directly operated. Since the learning is stored for each state, the retard amount corrected for knocking due to a transient state or noise is also learned. Therefore, there is a problem that the next time the same operation state is classified, the engine may be retarded too much and the best torque may not be obtained.

In order to solve the above problems, the learning value angle amount is learned and controlled so that the correction delay amount becomes a value in a predetermined range, and the same is always true under conditions where knocking easily occurs or when knocking does not easily occur. It is conceivable to perform knocking control. However, even with this method, the sum of the corrected retard amount and the learned retard amount becomes large, and the ignition timing may be delayed from the maximum retard condition of the ignition timing, leaving a problem that the output and fuel consumption deteriorate.

The present invention has been made to solve the above problems, and provides a knocking control method that always performs the same knocking control regardless of the knocking occurrence condition and prevents an extra retardation. The purpose is to

To achieve the above object, the structure of the first aspect of the present invention delays the ignition timing when knocking occurs and advances the ignition timing when knocking does not occur, from the basic ignition advance determined by the engine speed and the load. According to the operating state of the engine in order to bring the knocking level to a predetermined level, and the magnitude of the correction delay amount is equal to or greater than a first predetermined value or a second predetermined value. The ignition timing is controlled by subtracting the sum of the learning value angle amount rewritten by the learning control at the following time, and the sum of the learning retard amount and the correction retard amount is the basic ignition advance and the ignition timing. The learning retard amount is controlled so that the learning retard amount becomes a value equal to or smaller than the difference from the minimum ignition advance angle.

According to the configuration of the first aspect of the present invention, the ignition advance angle calculated by subtracting the sum of the corrected retard amount and the learned retard amount from the basic ignition advance is set to a predetermined ignition timing depending on the engine. Since the control is performed so as not to be on the retard side from the lower limit value (minimum ignition advance) on the side of the angle, it is possible to obtain a unique effect that the useless retard is lessened and the output and fuel consumption are improved.

The configuration of the second aspect of the invention is different from the configuration of the first aspect of the invention in that the learning retard amount and the correction retard amount are replaced by the method of limiting the sum of the learning retard amount and the correction retard amount. The learning retard amount is learned and controlled so that the sum of the values becomes less than or equal to the maximum retard amount from the basic ignition advance during the knocking control.

According to the configuration of the second aspect of the invention, the learning retard amount is learning-controlled to the optimum value so that the sum of the corrected retard amount and the learning retard amount is equal to or less than the maximum retard amount. The peculiar effect is that the optimum retardation amount is promptly obtained when the conditions are met.

Next, an example of an engine to which the present invention is applied is shown in FIG. As shown in the figure, this engine includes an air flow meter 2 as an intake air amount sensor provided on the downstream side of an air cleaner (not shown). The air flow meter 2 includes a compensation plate 2A rotatably provided in a damping chamber, and a potentiometer 2 for detecting the opening degree of the compensation plate 2A.
It is composed of B and. Therefore, the intake air amount Q is detected as the voltage output from the potentiometer 2B. An intake air temperature sensor 4 that detects the temperature of intake air is provided near the air flow meter 2.

A throttle valve 6 is arranged downstream of the air flow meter 2, and a surge tank 8 is provided downstream of the throttle valve 6.
Is provided. An intake manifold 10 is connected to the surge tank 8, and a fuel injection valve 12 is arranged so as to project into the intake manifold 10. The intake manifold 10 is connected to the combustion chamber 14A of the engine body 14 and is connected to the combustion chamber 1 of the engine.
4A is connected via an exhaust manifold 16 to a catalytic converter (not shown) filled with a three-way catalyst. The engine body 14 has a knocking sensor 1 configured by a microphone or the like for detecting engine vibration.
8 are provided. In addition, 20 is a spark plug, 22 is an O ₂ sensor for controlling the air-fuel mixture near the stoichiometric air-fuel ratio,
Reference numeral 24 is a cold / hot water temperature sensor for detecting the engine cooling water temperature.

The spark plug 20 of the engine body 14 is connected to a distributor 26, and the distributor 26 is connected to an igniter 28. This Distributor 2
6 is provided with a cylinder discrimination sensor 30 and an engine rotation angle sensor 32 which are composed of a pick-up and a signal rotor fixed to the distributor. The cylinder discrimination sensor 30 has, for example, a crank angle of 7
A cylinder discrimination signal is output every 20 degrees to an electronic control circuit 34 composed of a microcomputer, and the engine rotation angle sensor 32 outputs a crank angle reference position signal to the electronic control circuit 34, for example, every 30 degrees of the crank angle. To do.

The electronic control circuit 34, as shown in FIG.
Access memory (RAM) 36, read only memory (ROM) 38, and central processing unit (CPU) 4
0, a clock (CLOCK) 41, a first input / output port 42, a second input / output port 44, a first output port 46, and a second output port 48.
AM36, ROM38, CPU40, CLOCK41,
First input / output port 42, second input / output port 44, first
The output port 46 and the second output port 48 of are connected by a bus 50. An air flow meter 2, a cooling water temperature sensor 24, an intake air temperature sensor 4, etc. are connected to the first input / output port 42 via a buffer (not shown) multiplexer 54 and an analog-digital (A / D) converter 56. Has been done. This multiplexer 54 and
The A / D converter 56 is controlled by the signal output from the first input / output port 42. The O ₂ sensor 22 is connected to the second input / output port 44 via a buffer (not shown) and a comparator 62, and the cylinder discrimination sensor 30 and the engine rotation angle sensor 3 are connected via a waveform shaping circuit 64.
2 is connected. In addition, the bandpass filter 60 and the peak hold circuit 6 are connected to the second input / output port 44.
1. The knocking sensor 18 is connected via the channel switching circuit 66 and the A / D converter 68. This bandpass filter is connected to a channel switching circuit 66 via an integrating circuit 63. This channel switching circuit 6
6 includes an output of the peak hold circuit 61 and an integration circuit 63.
The control signal output from the second input / output port 44 for inputting either one of the output and the output of the second input / output port is input to the A / D converter 68, and the peak hold circuit 61 receives the second input / output port. A reset signal is input from 44. Further, the first output port 46 is connected to the igniter 28 via the drive circuit 70, and the second output port 48 is connected to the fuel injection valve 12 via the drive circuit 72.

The ROM 38 of the electronic control circuit 34 stores in advance a map of the basic ignition advance angle θ _BASE represented by the engine speed and the intake air amount and the basic fuel injection amount, and a signal from the air flow meter 2 and the engine rotation angle. Sensor 32
The basic ignition advance angle and the basic fuel injection amount are read by a signal from the engine, and the basic ignition advance angle and the basic fuel injection amount are corrected by various signals including the signals from the cooling water temperature sensor 24 and the intake air temperature sensor 4. The ignition advance and the corrected fuel injection amount are added, and the igniter 28 and the fuel injection valve 12 are controlled. The air-fuel ratio signal output from the O ₂ sensor 22 is used for air-fuel ratio control that controls the air-fuel ratio of the air-fuel mixture to near the stoichiometric air-fuel ratio. Further, the learning map shown in FIG. 1 is stored in advance in the RAM 36 of the electronic control circuit 34.

Next, an embodiment in which the present invention is applied to the above engine will be described in detail. In the description of the embodiments of the present invention, the fuel injection control, the air-fuel ratio control, the main routine of the ignition timing control, etc. are the same as the conventional ones, and therefore the description thereof will be omitted, and the knocking control related to the present invention will be omitted. Only the routine will be described.

FIG. 6 shows an interrupt routine for every 30 ° CA when the present invention is carried out by using a microcomputer. First, in step 81, the engine speed N is obtained from the rotation time based on the signal from the engine rotation angle sensor 32, and in step 82, the number of interrupts after the cylinder discrimination signal is input from the cylinder discrimination sensor 30 is counted. Set a flag that indicates the current crank angle. Next, in step 83, it is determined whether or not the flag set in step 82 is a top dead center (TDC) flag. When it is not the top dead center at present, the routine proceeds to step 88, and when it is now the top dead center, it is judged at step 84 whether or not the knock gate is closed. When the knock gate is open, the knock gate is closed at step 85, and when the knock gate is closed, the channel switching circuit 66 is switched at step 86 so that the engine vibration signal output from the knocking sensor 18 is transmitted to the band pass filter 6.
0, through integration circuit 63 and channel switching circuit 66
It is input to the A / D converter 68, and the A / D conversion of the average value of the engine vibration, that is, the background level is started. Then, at step 87, the closing time t ₁ of the knock gate,
That is, next, the time at which the knock gate is closed is calculated, and the time coincidence interrupt A is set.

Next, in step 88, it is determined whether or not the crank angle has reached 90 ° CA BTDC (before top dead center) based on the flag set in step 82. When the crank angle is not 90 ° CA BTDC, the routine proceeds to step 91, and when it is 90 ° CA BTDC, at step 89, the correction advance amount θ _K is updated and the ignition timing calculation processing is performed. explain). At step 90, the time coincidence interrupt B is set to find the time when the igniter 28 is turned on based on the ignition timing calculated at step 89 and the current time, and the igniter on flag is set. Then, in step 91, it is judged whether or not the crank angle has reached 60 ° CA BTDC. If it is not 60 ° CA BTDC, the process returns to the main routine, and if it is 60 ° CA BTDC, the igniter is turned off in step 92. The time is calculated, the time coincidence interrupt B is set, and the igniter-on flag set in step 90 is cleared.

Next, the time coincidence interrupt A shown in FIG. 7 will be described.
This interrupt routine is for obtaining the peak value of the engine vibration. When the time set in step 87 in FIG. 6 is reached, an interrupt is made, and the peak value held in the peak hold circuit 61 is transferred to the channel switching circuit in step 93. The peak hold value is input to the A / D converter 68 via 66 to start the A / D conversion of the peak hold value, and the process returns to the main routine.

FIG. 8 shows a routine of the time coincidence interrupt B. When the time set in step 90 and step 92 in FIG. At step 94, it is judged whether the igniter on flag is set, that is, whether this flag is 1 or not. When the flag is set, the igniter is turned on at step 96, and when the flag is set, the igniter is set at step 95. Turn off and return to the main routine.

FIG. 9 shows the A / D conversion completion interrupt routine, which is executed when the A / D conversion of the background level and the A / D conversion of the peak hold value are completed. First, in step 97, it is determined whether or not the knock gate is currently open. When the knock gate is closed, step 98 of FIG. 6 is executed at step 98.
The A / D conversion value converted in step 6 is stored in the memory of the RAM 36 to set it as the back ground level b. In step 99, the notch gate is opened and the process returns to the main routine. On the other hand, when the knock gate is open, the A / D converted value converted in step 93 of FIG. 7 is stored in the memory of the RAM 36 to be the peak value a, and the knock gate is closed in step 101 to return to the main routine.

FIG. 10 shows an interrupt routine that is performed every predetermined time (for example, 4 msec) for counting the time when the knocking does not occur and the learning control time. First, in step 102, the count value of the counter TIME 1 for obtaining the time when no knocking occurs is incremented by 1, and in step 103 the count value of the counter TIME 2 for obtaining the time for learning control is incremented by 1. At the next step 104, the counter TIME 1
It is determined whether or not the count value of is less than 12 (48 msec). When the count value exceeds 12, the count value of the counter TIME 1 is set to 12 in step 105, and when the count value is 12 or less, it is determined in step 106 whether the count value of the counter TIME 2 is 12 or less. . Here, when the count value exceeds 12, the count value of the counter TIME 2 is set to 12 in step 107 and the process returns to the main routine, and when the count value is 12 or less, the process returns to the main routine.

Next, the detailed routine of step 89 in FIG. 6 will be described with reference to FIG. When it is determined in step 88 of FIG. 6 that the crank angle has reached 90 ° CA BTDC, step 1
At 08, the peak value a stored at step 100 in FIG. 9 is compared with the background value b stored at step 98 in FIG. When the peak value a exceeds the value K · b, it is determined that knocking has occurred, and the correction retard angle amount θ _K is increased in step 110 by a predetermined angle (for example, 0.4 ° CA),
At step 112, the count value of the counter TIME 1 which counts the time when no knocking occurs is cleared. On the other hand, when the peak value a is equal to or less than the value K · b, it is determined that knocking does not occur, and it is determined in step 109 whether or not the count value of the counter TIME 1 is equal to or more than the predetermined value (12). Is greater than a predetermined value, the state in which no knocking has occurred continues for a predetermined time. Therefore, in step 111, the correction retard angle amount θ _K is decreased by a predetermined angle (for example, 0.08 ° CA), and then the step At 112, the counter TIME 1 is cleared.
If the count value is less than the predetermined value in step 109, the process proceeds to step 113. Step 11
In No. 3, the basic ignition amount is calculated by the corrected retard amount θ _K obtained as described above and the learned retard amount θ _KG obtained by the two-dimensional interpolation method from the learned map as shown in the above equation (1). The ignition advance angle θ _ig that actually controls the igniter is calculated by correcting the advance angle θ _BASE .

Next, a routine for obtaining the learning retard amount θ _KG corresponding to the current engine condition from the learning map and performing learning control will be described. FIG. 12 shows this routine from the middle of the main routine.

First, at step 114, the engine speed N and the load
Find the RAM addresses of four points surrounding the point indicating the current engine condition determined by Q / N on the learning map. Next, in step 115, the two-dimensional interpolation method (two-dimensional interpolation method) is performed on the basis of the data stored in the obtained four-point RAM addresses, that is, the learning delay amount stored in the four-point RAM addresses. The routine will be described later), and the learning retard amount θ _KG at the point indicating the current engine condition is calculated, and the calculated value is RA.
Store in a predetermined location of M. At step 116, the tenth
It is determined whether or not the count value of the counter TIME 2 for obtaining the learning control time counted in step 103 in the figure is a predetermined value (for example, 12) or more. If the count value is less than the predetermined value, return to the main routine,
If the count value is equal to or larger than the predetermined value, the count value of the counter TIME2 is cleared in step 117, and then the 11th
In step 118, it is determined whether or not the corrected retard amount θ _K updated in steps 110 and 111 is equal to or larger than the first predetermined crank angle (for example, 2 ° CA).

If it is determined in step 118 that the corrected retard amount θ _K is less than the first predetermined crank angle, in step 121 it is stored at four points on the learning map surrounding the point indicating the current engine condition. Learning control is performed to subtract a predetermined crank angle (for example, 0.04 ° CA) from each of the learning retard amounts, and the process returns to the main routine. As a result, when the corrected retard amount θ _K is less than the first predetermined crank angle, the learning control is performed so that the learning retard amount of the learning map becomes small, and the ignition timing is controlled to advance according to the learned retard amount. To be done. On the other hand, if it is determined in step 118 that the corrected retard amount θ _K is greater than or equal to the first predetermined crank angle, in step 119, the corrected retard amount θ _K is set to a value larger than the first predetermined crank angle. 2 predetermined crank angle (eg 4 ° C
It is determined whether or not less than A). When it is determined in step 119 that the corrected retard amount θ _K is less than the first predetermined crank angle, that is, when the corrected retard amount θ _K satisfies the following condition, the first predetermined crank angle ( 2 ° CA) ≤ θ _K <second predetermined crank angle (4 ° CA) (7) Return to the main routine without learning control. As a result, the learning control is not performed when the corrected retard amount θ _K takes a value in the predetermined range, and the ignition timing is not changed depending on the learned retard amount. It should be noted that learning control may be performed as necessary even when the correction delay amount takes a value within a predetermined range. If it is determined in step 119 that the corrected retard amount θ _K is greater than or equal to the second predetermined crank angle, in step 120, the learning delays stored at the four points on the learning map surrounding the point indicating the current engine condition are stored. Learning control for adding a predetermined crank angle (for example, 0.04 ° CA) to each angular amount is performed, and the process returns to the main routine. As a result, the learning control is performed so that the learning delay amount of the learning map becomes large when the corrected retard amount θ _K is equal to or greater than the second predetermined crank angle, and the ignition timing is delayed by the learning retard amount. To be done.

By performing the learning control as described above, the learning delay amount of the learning map is changed so that the correction delay amount becomes a value within a predetermined range.

The learning routine of FIG. 12 will be described in detail below.

FIG. 13 shows a detailed routine of the two-dimensional interpolation method in step 115 of FIG. In this two-dimensional interpolation routine, the map shown in FIG. 1 is used as a learning map, and the four RAM addresses indicating the current engine conditions are set to n, n + 1, n + 6, n + 7 as shown in FIG. . First, in step 130, the present load Q / N
Is the upper limit of the load on the learning map, ie 1.2 [/ re
v.] Judge whether or not the following. The load is 1.2 [/
rev.] is exceeded, 1.2 is stored in the register n in step 131, and if the load is 1.2 [/ rev.] or less, the current load Q / N value is read in step 134. Are stored in the register n. In step 135, it is determined whether or not the current engine speed N is the upper limit value of the engine speed on the learning map, that is, 6000 [r.p.m] or less. When the engine speed exceeds 6000 [rpm], step 136 stores 6000 in the register m, and when the engine speed is 6000 [rpm] or less, step 137. Is the current engine speed N
Store the value in register m. In step 138, it is judged whether or not the value of the register n is not less than the lower limit value of the load on the learning map, that is, 0.6 [/ rev.], And when the value of the register n is less than 0.6, step 139. When the value of the register n is set to 0.6 and the value of the register n is 0.6 or more, the process proceeds to step 140. Then, in step 140, the value of the register m is the lower limit value of the engine speed on the learning map, that is, 1000 [r.p.p.
m] or more, and the value of register m is 1000
If it is less than 1, the value of the register m is set to 1000 in step 141, and if the value of the register m is 1000 or more, the process proceeds to the next step 142. As a result, when the current engine speed N and the load Q / N are values on the learning map, the values are stored in the registers m and n, respectively, and the current engine speed N and the load Q / N are learned by the learning map. When the upper and lower limits are exceeded, the upper and lower limits are stored in registers m and n, respectively.

Steps 142 to 149 are a routine for selecting four points on the learning map. First, in step 142, a value obtained by subtracting the load value of 0.6 [/ rev.] From address 0 from the value of register n is stored in register n. Next, in step 143, the value of the register n is divided by 0.2 [/ rev.], Which is the scale interval of the load,
The integer part of the quotient is stored in register n, and the remainder of the quotient is stored in register y. The value of this register is equal to the load value y from the address n in FIG. 2 to the point indicating the current engine condition. In addition, the integer part of the quotient stored in the register n is a column of addresses that are closest to the point indicating the current engine condition and are equal to or less than the point indicating the current engine condition (horizontal arrangement of addresses, for example, addresses 0 to 5). Is the first column)
Indicates the column number of. Then, in step 144, the value of the register y is further divided by 0.2 [/ rev.]. Therefore, finally, in the register y, y in the equation (6) described above is written.
The value corresponding to / Y is stored.

In step 145, the value of the engine speed at address 0 is 1000 [r · p · m] from the value of register m, as described above.
The value obtained by subtracting is stored in the register m. Next, in step 146, the value of the register m is divided by the scale interval of the engine speed, 1000 [r.p.m], the integer part of the quotient is stored in the register m, and the remainder of the quotient is stored in the register x. Remember. The value of the register x is equal to the engine speed value x from the address n in FIG. 2 to the point indicating the current engine condition. In addition, the integer part of the quotient stored in the register m is the row of the addresses that are closest to the point indicating the current engine condition and are equal to or less than the point indicating the current engine condition (a vertical array of addresses, for example, 0, 6, The row numbers of addresses 12 and 18 are the first row). Then, in step 147, the value of the register x is further increased to 1000 [rp.
m]. Therefore, finally, the value corresponding to x / X of the equations (4) and (5) is stored in the register x.

Next, in step 148, the value of the register n is multiplied by 6 and stored in the register n, and in the next step 149, the value of the register n and the value of the register m are added and stored in the register n. As a result, the addresses at the lower left corners of the four points surrounding the current engine condition, that is, the address number of address n in FIG. 2 are obtained and stored in the register n.

In step 150, the learning delay amount θ _KGn stored at the address n on the learning _map is read and stored in the register A, and the learning delay amount θ stored at the address n + 1.
_{KG (n + 1)} is read and stored in the register B, the learning retard amount θ _{KG (n + 6)} stored in the address _{n + 6} is read and stored in the register C, and stored in the address n + 7. The learning retard amount θ _{KG (n + 7)} is read out and stored in the register D. Then, in step 151, the value of register B is subtracted from the value of register A and the value of register x is multiplied,
Further, the value of the register A of that value is added and stored in the register E. In step 152, the value of register D is subtracted from the value of register C, the value of register x is multiplied, and the value of register C is added to that value to register F.
To memorize. And finally in step 153,
The value of the register F is subtracted from the value of the register E, the value of the register y is multiplied, and the value of the register E is added to the value to obtain the learning retard amount θ _{KG at the} point indicating the current engine condition. .

Next, FIG. 14 shows a detailed routine of steps 118 to 121 in FIG. The register n in FIG. 14 uses the register n of the two-dimensional interpolation routine in FIG. First, in step 118, it is determined whether or not the corrected retard angle θ _K is 2 ° CA or more, as described above. When the corrected retard amount θ _K is less than 2 ° CA, the learning value α is set to -0.04 ° CA in step 160 and the process proceeds to step 162. If the corrected retard amount θ _K is 2 ° CA or more, the corrected retard amount θ _K is determined in step 119.
Judgment is over 4 ° CA. Corrected retard angle θ
_{When K} is less than 4 ° CA, the process returns to the main routine, and when the correction retard angle θ _K is 4 ° CA or more, the learning value α is set to 0.04 ° CA in step 161, and the process proceeds to step 162. In step 162, it is judged whether the load Q / N is equal to or more than the lower limit value 0.6 [/ rev.] Of the learning map. Step 1 if the load is 0.6 or more
At 66, the engine speed N is the lower limit value 10 of the learning map.
If the load is less than 0.6, it is determined in step 163 whether the engine speed N is 1000 [r · p · m] or less. To judge.

At step 166, the engine speed N is 1000 [r
.P.m], the step 167
At the nth address, the previously learned learning delay amount θ
Learning control is performed by adding the learning value α to _KGn , and in step 168, learning control is performed by adding the learning value α to the previously learned learning retard amount θ _{KG (n + 1)} at address _{n + 1.} And return to the main routine. Here, as described above, the current engine speed N and load Q / N are Q / N ≧
If it exists in the area of 0.6 [/ rev.] And N <1000 [r.p.m], register n indicating the address of RAM
Since the value of can take 0, 6, 12, 18 in the first row, if the point indicating the current engine condition exists in the above area, the learning delay of addresses 0, 6, 12, 18 is performed in step 167. The angle amount is learned and controlled, and at steps 168, 1, 7, 13,
The learning retard amount of the address 19 is controlled to be learned.

At step 166, the engine speed N is 1000 [r.
If it is determined that the value is greater than or equal to p · m], learning control is performed in step 169 in which the learning value α is added to the previously learned learning retard amount θ _KG at address n. The point that shows the current engine condition is Q / N ≧ 0.6 [/ rev.] And N ≧
If it exists in the area of 1000 [r ・ p ・ m], RA
Since the value of the register n indicating the address of M can be 0 to 23, all addresses are subject to learning control in step 169. At the next step 170, it is judged whether or not the value of the register n is 23. If the value of the register n is not 23, it is determined in step 171, step 173, and step 174 whether the value of the register n is not 17, 11 or 5, respectively.
The values 5, 11, 17, and 23 of this register n represent the addresses in the sixth row. When the value of the register n is 23, the process directly returns to the main routine. At this time, the learning retard amount of the address 23 is learning-controlled in step 169. When the value of the register n is 17, 11 or 5, the value of the register n is decremented by 1 in step 172, and the learning value α is added to the learning delay amount θ _{KG (n + 7)} at address n + 7 in step 178. The learning control to
Return to the main routine. Therefore, when the value of the register n is 17, 11 or 5, 1 is set in step 169.
The learning delay amounts at addresses 7, 11, and 5 are learning-controlled, and at step 178, the learning delay amounts at addresses 23, 17, and 11 one row above are learning-controlled.

If the value of the register n is not 23, 17, 11, or 5, learning control is performed in step 175 in which the learning value α is added to the learning delay amount θ _{KG (n + 1)} at the address _{n + 1.} Be seen. That is, when the RAM address obtained in step 149 of the two-dimensional interpolation routine is not on the sixth line, the RAM address obtained in the two-dimensional interpolation routine and the address on the right of this address are obtained in steps 169 and 175. Is learning controlled. In step 176, register n
Is less than 17, and if the value of the register n is 17 or more, the process returns to the main routine. That is, when the RAM addresses are 18 to 22 in the fourth column, the addresses stored in the register n in steps 169 and 175 and the addresses to the right of the addresses are learned and controlled. On the other hand, when the value of the register n is less than 17, that is, the point indicating the current engine condition is surrounded by 4
If one address exists, learning control is performed in step 177 to add the learning value α to the learning delay amount θ _{KG (n + 6)} at address n + 6, and in step 178 the learning delay amount θ _KG at address n + 7 θ _{KG (n + 6).} Learning control is performed to add the learning delay α to _{(n + 7)} .
As a result, when there are four addresses surrounding the point indicating the current engine condition, step 169, step 17
5, the learning delay amounts of the above-mentioned four addresses are learning-controlled in steps 177 and 178.

When it is determined in step 162 that the load is less than 0.6 [/ rev.], The engine speed is 1000 in step 163.
It is determined whether or not [r · p · m] or less, and if the engine speed is 1000 [r · p · m] or less, step 165
Then, 7 is subtracted from the value of the register n, and learning control is performed in step 178. Point indicating current engine condition Q / N <0.6
[/ Rev.] And N ≦ 1000 [r · p · m], the value of the register n becomes 0. Therefore, in this case, the learning delay amount at address 0 is learned and controlled. Will be. On the other hand, the engine speed N is 1000
When [r · p · m] is exceeded, step 164
, It is judged whether or not the value of the register n is 5, and
If not, 6 is subtracted from the value of the register n in step 179, and the learning retard amount of the addresses n + 6 and n + 7 is learned and controlled in steps 177 and 178. When the value of register n is 5, step 180 subtracts 7 from the value of register n, and then step 178
Learning control is performed in. Q / N <0.6 [/ rev.] And N> 1000 [rp
m], the value of register n is the first
Since the value of the address of the column can be taken, when the value of the register n is 5, the learning delay amount of the address 5 is learned and controlled in step 178, and when the value of the register n is 0, 1, 2, 3, or 4. In step 177 and step 178, the learning retardation amount of the address of the value of the register n and the address on the right side thereof are learned and controlled.

The following table summarizes the relationship between the condition of the corrected retard amount θ _K and the increase / decrease of the learned retard amount θ _KG when updating the learned retard amount θ _KG in the learning routine of FIG. 14 by the learning control. Show.

Further, FIG. 15 shows changes in the corrected retard amount θ _K , the learned retard amount θ _KG , and the ignition timing θ _{ig over} time. As can be seen, the retard amount theta _KG learning when the correction retard amount theta _K value of the predetermined range is constant, the retard amount learning when the delay correction amount theta _K exceeds the predetermined range theta _KG increases, and decreases when the corrected retard angle θ _K is less than the predetermined range.

Further, FIG. 16 shows the variation of the ignition timing corresponding to the engine speed. Curves C _{1 to} C ₃ in FIG. 16 are the same as those in FIG. 3, and the correction retard angle amount θ _K is always constant regardless of whether knocking is likely to occur or when knocking is unlikely to occur. To be understood.

FIG. 17 shows an interrupt routine executed at each predetermined crank angle (for example, 90 ° CA) for setting the sum of the corrected retard amount and the learned retard amount in the first invention within a predetermined range. Similar to steps 108 to 112 in FIG. 11, steps 182 to 187 in the figure are routines for changing the correction delay amount in accordance with the occurrence of knocking. In step 187, the value obtained by subtracting the minimum ignition retard amount θ _min of the ignition timing from the basic ignition advance θ _BASE and further subtracting the learning retard amount θ _KG calculated by the two-dimensional interpolation method is stored in the RAM as RA. Let In the next step 188, RA
Is greater than or equal to 0, and if it is greater than or equal to 0, RA is compared with the correction retard angle θ _{K in} step 189, and if less than 0, the value of RA is rewritten to 0 in step 190. Proceed to step 191. When it is determined in step 189 that the corrected retard amount θ _K is larger than the RA value, the process proceeds to step 191, and when it is determined that the corrected retard amount θ _K is equal to or less than the RA value, the process proceeds to step 192. Then, in step 191, the value of the corrected retard angle θ _K is rewritten to the value of RA, and in step 192, the ignition advance angle θ is calculated according to the above equation (1).
Calculate _ig . In the next step 193, the ignition advance angle θ _ig
And the minimum ignition advance angle θ _min, and the minimum ignition advance angle θ _min
Is larger than the ignition advance angle θ _ig, at step 194, the value of the minimum ignition advance angle θ _min is set to the ignition advance angle θ _{ig and the} process returns to the main routine, and the value of the ignition advance angle θ _ig is changed to the minimum ignition advance angle θ _ig.
If it is more than _min , it returns to the main routine.

The above routine will be further described with reference to FIGS. 18 (A) and 18 (B). FIG. 18 (A) shows the case where the value of RA is positive, and FIG. 18 (B) shows the case where the value of RA is negative. The change from the state (1) in FIG. 18 (A) to the state (2) is performed in steps 189 and 191. In the state of (2), since the corrected retard amount is 2 ° CA or less, the learning retard amount θ _KG becomes small by the learning control, and the state of (3) is obtained. The change from the state (1) to the state (2) in FIG. 18B is performed at steps 188, 190 and 191. That is, since the value of RA is negative, the value of the correction value angle amount θ _K is set to 0 in step 190 and step 191 to enter the state of (2), and the learning delay amount θ _KG is gradually increased by the learning control thereafter. Is reduced to the state of (3) and proceeds to the state of (4). The eighteenth
When the ignition advance angle is smaller than the minimum ignition advance angle as in the state (1) of FIG. (A) and the states (1) and (2) of FIG. 18B, step 193 and step 194 are performed. The minimum spark advance is used as shown in FIG.

FIG. 19 shows an interrupt routine executed at each predetermined crank angle (for example, 90 ° CA) for setting the sum of the corrected retard amount and the learned retard amount within the predetermined range in the second invention.
The routine of FIG. 19 is a combination of the routine of the first invention and the routine of the second invention. Routines of Steps 182 to 191 and Step 19
3. The routine of step 194 is the same as that of FIG. 17, and therefore its explanation is omitted. In step 196, the maximum value of the sum of the corrected retard amount and the learned retard amount, that is, the maximum retard amount θ _{kmax minus the} learned retard amount θ _K is stored in the RAM as RA. In step 197, it is determined whether or not the value of RA is less than the correction retard amount θ _K.
When the value of RA is less than the correction retard amount θ _K , the value of RA is set to the learning retard amount θ _K in step 198 and the process proceeds to step 199. When the value of RA is equal to or more than the correction retard amount θ _K , , And proceed to step 199 as it is. Step 19
9, the ignition advance angle θ _{ig is calculated} based on the equation (1) as described above.
To calculate.

According to the above routine, the learning control is performed so that the sum of the learning retard amount and the correction retard amount is equal to or less than the difference between the basic ignition advance amount and the minimum retard amount or the maximum retard amount. Although an example in which the first invention and the second invention are combined has been described above, only the routine of the second invention may be executed independently.

FIG. 20 shows changes in the learning retard angle and the ignition advance angle according to the present invention, and the learning retard angle amount and the ignition advance angle when the learning retardation amount is simply controlled so that the corrected retard angle amount falls within a predetermined range (hereinafter referred to as a comparative example). Shows the change of. In the figure, a curve C ₅ is a learning retard amount of the present invention, C ₆ is a learning retard amount of a comparative example, C ₇ is a slight knock occurrence ignition timing, C ₈ is an ignition advance angle of the present invention, and C ₉ is a comparative example. Ignition advance angle is shown respectively. As will be understood from the figure, according to the present invention, it is possible to prevent an additional delay as in the comparative example.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a learning map, FIG. 2 is an explanatory diagram showing a point indicating a current engine condition and four points surrounding this point, and FIG. 3 is a line showing a relationship between an engine speed and an ignition timing. Figure,
4 is a schematic diagram showing an engine to which the present invention is applied, FIG. 5 is a block diagram showing the electronic control circuit of FIG. 4, FIG. 6 is a flow chart of an interrupt routine every 30 ° CA, and FIG. 7 is FIG. 8 is a flow chart of the time coincidence interrupt A, FIG. 9 is a flow chart of the A / D completion interruption routine, and FIG. 10 is a flow chart showing an interruption routine every 4 msec.
FIG. 1 is a flow chart of a routine for updating the corrected retard amount,
FIG. 13 is a flow chart of the learning control routine, FIG. 13 is a flow chart of the two-dimensional interpolation routine, FIG. 14 is a flow chart showing the details of the learning routine, and FIG. 15 is a correction delay amount / learning delay amount / ignition with respect to the passage of time. FIG. 16 is a diagram showing the variation of the timing, FIG. 16 is a diagram showing the relationship between the engine speed and the ignition timing, which is the same as FIG. 3, and the relationship between the correction retard amount and the learning retard amount, and FIG. 18 is a flow chart showing a routine for setting the retard amount in a predetermined range, FIGS. 18 (A) and 18 (B) are explanatory views for explaining the routine of FIG. 17, and FIG. FIG. 20 is a flow chart showing a routine for setting the retard amount in the second invention within a predetermined range, and FIG. 20 is a diagram showing a change in ignition timing of the present invention. 2 ... Air flow meter, 12 ... Fuel injection valve, 18 ... Notking sensor, 32 ... Engine rotation angle sensor, 34 ... Electronic control circuit.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Toshio Suematsu 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Corporation (56) Reference JP-A-57-105530 (JP, A)

Claims (2)

[Claims] 1. A correction retard amount that is changed from a basic ignition advance determined by engine speed and load so as to delay the ignition timing when knocking occurs and advance the ignition timing when knocking no longer occurs. , A learning delay that is rewritten by learning control according to the operating state of the engine in order to bring the knocking level to a predetermined level and when the magnitude of the correction delay amount is equal to or greater than a first predetermined value or less than a second predetermined value. The ignition timing is controlled by subtracting the sum with the angle amount, and the sum of the learned retard amount and the corrected retard amount is less than or equal to the difference between the basic ignition advance and the minimum ignition advance of the ignition timing. A method for controlling knocking of an internal combustion engine, wherein learning control is performed on the learned value angular amount so as to obtain a value. 2. A corrected ignition retard amount, which is changed from a basic ignition advance determined by the engine speed and a load so as to delay the ignition timing when knocking occurs and advance the ignition timing when knocking no longer occurs. , A learning delay that is rewritten by learning control according to the operating state of the engine in order to bring the knocking level to a predetermined level and when the magnitude of the correction delay amount is equal to or greater than a first predetermined value or less than a second predetermined value. The ignition timing is controlled by subtracting the sum with the angle amount, and the sum of the learned retard amount and the corrected retard amount is set to a value equal to or less than the maximum retard amount from the basic ignition advance angle. A method for controlling knocking of an internal combustion engine, wherein learning control is performed on the learning retard amount.