JPH0711265B2 - 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 for correcting the basic ignition advance angle and controlling knocking by performing a retard angle at a relatively slow speed and changing the learning retard angle by 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 predetermined by the load determined by the intake pipe negative pressure, is stored in the form of a map in the read-only memory (ROM) of the microcomputer, and is actually calculated based on the following equation (1). The ignition advance angle θig for controlling the igniter is calculated, and the knocking control is performed using this ignition advance angle.

θig = θ _BASE − (θ _KG + θ _K ) (1) However, θ _KG is determined by the engine speed and load and is changed by learning control in order to bring the level of knocking to a predetermined level. The learning retard amount, θ _K, is a correction 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 vibration of the engine is detected using a knocking sensor composed of a microphone or the like, and a predetermined multiple K · b (where K is a proportional constant) of the average value (back ground) b of the engine vibration and the peak value of the engine vibration. a is obtained, and the peak value a and the value of K · b are compared. The peak value a is K
When the value of b is exceeded, it is determined that knocking has occurred, and as shown in the following equation (2), the correction retardation amount θ _K is set so that the ignition timing is delayed by a predetermined crank angle (for example, 0.4 ° C A) per occurrence of knocking. change.

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

θ _K ← θ _K −0.08 ° C. A (3) Further, the learning retard amount θ _KG according to the engine condition is calculated as follows. First, as shown in FIG. 1, the random access memory (RAM) of the microcomputer is provided with addresses 0 to 23 for storing the learning retard amount in association with the engine speed N and the load Q / N, and the learning map is prepared. Is created. The engine speed N and the intake air amount Q are taken in and a point (N, Q /
Find the addresses of 4 RAMs surrounding N). Now, as shown in FIG. 2, the RAM addresses surrounding the points indicating the current engine state are n (n = 0, 1, ... 16), n + 1, n + 6, n + 7, and the learning delay amount is set at the address n. θ _KG n, learning delay amount θ _{KG (} n ₊₁₎ at address n + 1, learning delay amount θ _{KG (} n ₊₆₎ at address n + 6, learning delay amount θ _{KG (} n ₊₇₎ at address n + 7, respectively. It is assumed to be remembered. 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 retardation amount θ _{KG at the} point indicating the current engine state is obtained by the two-dimensional interpolation method shown in the following equations (4) to (6). To be

Thus, the corrected retard angle θ changed as described above
_{Using K} and the learning retard 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 corrected based on the equation (1) to control the knocking. Of.

By the way, as shown in FIG. 3, basic ignition advance θ _BASE, that is, MBT (Minimum Spark Advance for Best Torque)
Changes like a curve C ₁ according to the engine speed.
Further, the micro Notsukingu occurrence ignition timing when Notsukingu when such air is Shimetsu hardly occurs is as shown in curve C _2, micro Notsukingu occurrence when prone Notsukingu when such air is dry occurs Ignition timing is as shown by curve C ₃ . Therefore, the minute knocking occurrence ignition timing differs depending on the engine speed and the environmental conditions.

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 such a problem, Japanese Patent Laid-Open No. 56-23566 proposes a learning control method in which the operating states of the engine are classified and learning is performed for each classification.

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. In other words, since knocking due to noise or the like is also learned, there is a problem that the best torque may not be obtained even when the same operating state classification is entered next time. .

The present invention has been made to solve the above problems, and can always perform the same knocking control under conditions where knocking is likely to occur and conditions where knocking is unlikely to occur, and is stable against knocking due to noise or the like. An object of the present invention is to provide a knocking control method capable of controlling ignition timing.

In order to achieve the above object, the configuration of the present invention is a basic ignition advance determined by the engine speed and the load, delays the ignition timing when knocking occurs, and advances the ignition timing when no knocking occurs, and a correction retard amount. In the knocking control method of the internal combustion engine, which calculates the ignition timing by subtracting the sum with the learning retard amount changed by the learning control, when the corrected retard amount exceeds a preset predetermined range, the learning is performed. The retard amount is retarded, and when the learning retard amount is less than the predetermined range, the learning retard amount is advanced, and the update amount when retarding or advancing the learning retard amount is updated by the correction retard amount. It is set smaller than the amount. In the above configuration, it is preferable that the learning control is not performed when the correction delay amount takes a value within the predetermined range.

According to the above configuration of the present invention, the learning retard amount is learned and controlled to the advance side or the retard side so that the correction retard amount falls within a predetermined range, for example, 2 ° C ≤ θ _K ≤ 4 ° C. , It is not necessary to perform learning control on the advance side for a relatively long time (16 sec) as in the past, and the speed of the learning control on the advance side can be made to be as high as the speed of the learning control on the retard side. Therefore, the ignition timing is not delayed too much, and the value learned once is retained until the next learning, so that the occurrence of knocking is reduced and the program of the conventional third counter can be omitted. A unique effect is obtained.

Further, by setting the update amount when retarding or advancing the learning retard amount to be smaller than the update amount of the correction retard amount, the update speed of the correction retard amount can be increased and the responsiveness to knocking can be improved. In addition to being improved, the correction by learning is performed relatively slowly, so that the fluctuation of the ignition timing becomes small and stable knocking control can be realized.

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 is composed of a compensation plate 2A that is rotatably provided in the damping chamber, and a potentiometer 2B that detects the opening degree of the compensation plate 2A. Therefore, the intake air amount Q is detected as the voltage output from the potentiometer 2B. Also,
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 a combustion chamber 14A of the engine body 14, and the combustion chamber 14A of the engine is connected via an exhaust manifold 16 to a catalytic converter (not shown) filled with a three-way catalyst. Further, the engine body 14 is provided with a knocking sensor 18 configured by a microphone or the like for detecting vibration of the engine. Reference numeral 20 is a spark plug, 22 is an O ₂ sensor for controlling the air-fuel mixture in the vicinity of the stoichiometric air-fuel ratio, and 24 is a cooling water temperature sensor for detecting the engine cooling water temperature.

The spark plug 20 of the engine body 14 is a distributor.
26, the distributor 26 is connected to an igniter 28. The distributor 26 is provided with a cylinder discriminating sensor 30 and an engine rotation angle sensor 32 which are composed of a pick-up and a signal rotor fixed to the distributor shaft. The cylinder discrimination sensor 30 is, for example, an electronic control circuit configured by a microcomputer or the like for a cylinder discrimination signal for each crank angle of 720 degrees.
The engine rotation angle sensor 32 outputs a crank angle reference position signal to the electronic control circuit 34 every 30 degrees of the crank angle.

As shown in FIG. 2, the electronic control circuit 34 includes a random access memory (RAM) 36, a read only memory (ROM) 38, a central processing unit (CPU) 40, and a clock (CLOCK) 41. And a first input / output port 42, a second input / output port 44, a first output port 46, and a second output port 48. The RAM 36, ROM 38, CPU 40, CLOCK
41, the first input / output port 42, the second input / output port 44, the first output port 46, and the second output port 48 are connected to the bus 50.
Connected by. The air flow meter 2, the cooling water temperature sensor 24, the intake air temperature sensor 4, etc. are connected to the first input / output port 42 via a buffer (not shown), a multiplexer 54, and an analog-digital (A / D) converter 56. It is connected. This multiplexer 54 and A / D converter 56
Are controlled by signals 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 32 are connected via a waveform shaping circuit 64. ing. Also, the second
A knotting sensor 18 is connected to the input / output port 44 via a bandpass filter 60, a peak hold circuit 61, a channel switching circuit 66 and an A / D converter 68. This bandpass filter is connected to a channel switching circuit 66 via an integrating circuit 63. This channel switching circuit
The control signal output from the second input / output port 44 for inputting one of the output of the peak hold circuit 61 and the output of the integration circuit 63 to the A / D converter 68 is input to 66. The peak hold circuit 61 has a second input / output port.
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 device 12 via the drive circuit 72.

In the ROM 38 of the electronic control circuit 34, the map of the basic ignition advance angle θ _BASE represented by the engine speed and the intake air amount, the basic fuel injection amount, and the like are stored in advance, and the signal from the air flow meter 2 and the engine speed are stored. The basic ignition advance and the basic fuel injection amount are continuously output by the signal from the angle sensor 32, and the basic ignition advance and the basic fuel injection are performed by various signals including the signals from the cooling water temperature sensor 24 and the intake air temperature sensor 4. The corrected ignition advance and the corrected fuel injection amount are added to the amount, 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 previously stored 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 embodiment 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 ° C. A when the present invention is carried out by using a microcomputer. First, at step 81, the engine speed N is obtained from the rotation time based on the signal from the engine rotation angle sensor 32, and the step is performed.
At 82, the number of interrupts after the cylinder discrimination signal is input from the cylinder discrimination sensor 30 is notified and a flag indicating the current crank angle is set. Next, in step 83, it is determined whether or not the flag set in step 82 is a top dead center (TDC) flag. Step if not currently at top dead center
If it is at the top dead center at 88, it is determined at step 84 whether the knock gate is closed or not. If the knock gate is open, close it at step 85; if the knock gate is closed, go to step 85.
At 86, the channel switching circuit 66 is switched so that the engine vibration signal output from the knocking sensor 18 is transferred to the bandpass filter 60, the integrating circuit 63, and the channel switching circuit 66.
To the A / D converter 68 to start the A / D conversion of the average value of engine vibration, that is, the back ground level.
Next, 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, at step 88, it is judged based on the flag set at step 82 whether or not the crank angle has reached 90 ° C BTDC (before top dead center). If the crank angle is not 90 ° C BTDC, proceed to step 91. If the crank angle is 90 ° C BTDC, step 89.
In step (1), the corrected advance angle θ _K is updated and the ignition timing is calculated (the details will be described below). In 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 in 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 ° C BTDC, and 60
If it is not ℃ A BTDC, it returns to the main routine, and if it is 60 ℃ A BTDC, it calculates the off time of the igniter in step 92, sets the time match interrupt B, and sets the igniter on flag set in step 90. Grate

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, and an interrupt is made at the time set in step 87 of FIG. 6, and the peak value held in the peak hold circuit 61 in step 93 is changed to the channel switching circuit. The value is input to the A / D converter 68 via 66 to start the A / D conversion of the peak hold value and return to the main routine.

FIG. 8 shows the 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. Off,
Return to the main routine.

FIG. 9 shows an A / D conversion completion interrupt routine, which is executed when the background level A / D conversion and the peak hold value A / D conversion are completed. First, in step 97, it is determined whether the knock gate is currently open. When the knock gate is closed, the A / D conversion value converted in step 86 of FIG. 6 is stored in the memory of the RAM 36 to be the back ground level b in step 98, and the not gate is opened in step 99 to return to the main routine. . On the other hand, when the knock gate is open, the A / D conversion value converted in step 93 of FIG. 7 is stored in the memory of the RAM 36 and the peak value a
Then, in step 101, the knock gate is closed and the process returns 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 TIME1 for determining the time when no knocking occurs is incremented by 1, and in step 103, the count value of the counter TIME2 for determining the time for learning control is incremented by 1. At the next step 104, the count value of the counter TIME1 is
Judge whether it is 12 (48msec) or less. When the count value exceeds 12, the count value of the counter TIME1 is set to 12 in step 105, and the count value becomes 12
In the following cases, it is determined in step 106 whether the count value of the counter TIME2 is 12 or less. Here, when the count value exceeds 12, step 107
In, the count value of the counter TIME2 is set to 12, and the process returns to the main routine. 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. The crank angle is 90 ° C at step 88 in Fig. 6.
When it is determined that the ABTDC has been reached, in step 108, the peak value a stored in step 100 of FIG.
The back ground level b stored in step 98 of FIG. 9 is compared with a value K · b obtained by multiplying the back ground level b by a constant K. When the peak value a exceeds the value K · b, it is determined that knocking has occurred, and in step 110, the corrected retard angle θ _K
Is increased by a predetermined angle (for example, 0.4 ° C. A), and the count value of the counter TIME1 for counting the time in which knocking does not occur in step 112 is cleared. On the other hand, the peak value a
Is less than the value K · b, it is determined that knocking does not occur, and it is determined in step 109 whether the count value of the counter TIME1 is greater than or equal to the predetermined value (12), and the count value is greater than or equal to the predetermined value. In this case, since the state in which no knocking occurs continues for a predetermined time, the correction retard angle amount θ _K is set to a predetermined angle (eg 0.08) in step 111.
℃ A) After the decrease, at step 112, the counter TIME1 is cleared. If the count value is less than the predetermined value in step 109, the process proceeds to step 113. In step 113, the corrected retard amount θ obtained as described above
_The basic ignition advance angle θ _BASE is corrected by _K and the learning delay amount θ _KG obtained by the two-dimensional interpolation method from the learning map as shown in the above equation (1) to actually control the igniter. Calculate the angle θig.

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, engine speed N and load Q / N
RA of 4 points surrounding the point that shows the current engine condition determined by
Find the address of M on the learning map. Next, in step 115, the two-dimensional interpolation method (two-dimensional interpolation method) is performed based on 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 stored in a predetermined location of the RAM. In step 116, a counter TI for obtaining the learning control time counted in step 103 of FIG.
It is determined whether the count value of ME2 is a predetermined value (for example, 12) or more. If the count value is less than the predetermined value, the process returns to the main routine, and if the count value is more than the predetermined value, the counter TIME2 is cleared in step 117 and then updated in steps 110 and 111 in FIG. The corrected correction angle amount θ _K is the first predetermined crank angle (for example, 2 ° C. A).
It is determined in step 118 whether or not the above is true.

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, the learning map surrounding the point indicating the current engine condition is set to 4
Learning control is performed to subtract a predetermined crank angle (for example, 0.04 ° C. A) from each of the learning delay amounts stored at the points, and the process returns to the main routine. As a result, the correction retard angle θ
_{When 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 smaller, and the ignition timing is controlled so as to advance according to the learning retard amount. On the other hand, if it is determined in step 118 that the corrected retard amount θ _K is equal to or larger than the first predetermined crank angle, in step 119, the corrected retard amount θ _K is larger than the first predetermined crank angle. It is determined whether or not it is less than a predetermined crank angle of 2 (for example, 4 ° C. 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 ° C A) ≤ θ _K <second predetermined crank angle (4 ° C A) (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 in the four points on the learning map surrounding the point indicating the current engine condition are stored. Learning control is performed to add a predetermined crank angle (for example, 0.04 ° C. A) to each of the angular amounts, 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 shown in 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 the learning map, and the four RAM addresses indicating the current engine conditions are assigned to the second map.
As shown in the figure, n, n + 1, n + 6, and n + 7. First, in step 130, it is judged whether or not the current load Q / N is less than or equal to the upper limit value of the load on the learning map, that is, 1.2 [/ rev.]. If the load exceeds 1.2 [/ rev.], 1.2 is stored in register n in step 131 and the load is
If it is less than 1.2 [/ rev.], The current load Q / N value is stored in the register n in step 134. In step 135, it is determined whether or not the current engine speed N is less than or equal to the upper limit value of the engine speed on the learning map, that is, 6000 [rpm]. When the engine speed exceeds 6000 [rpm], 6000 is stored in the register m in step 136, and when the engine speed is less than 6000 [rpm], the current engine speed N of step 137 is stored. Store the value in register m. In step 138, the value of the register n is the lower limit value of the load on the learning map, that is, 0.6 [/r.ev.].
It is determined whether or not it is above, and if the value of the register n is less than 0.6, the value of the register n is changed in step 139.
When 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, 10
If the value of the register m is less than 1000, 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 next step 142 is executed. move on. 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, the load value at address 0 from the value of register n is 0.6 [/ re
The value obtained by subtracting v.] is stored in the 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, and the integer part of the quotient is stored in the register n and the remainder of the quotient is stored in the register y. The value of this register y is equal to the value y of the load from 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). Then, in step 144, the value of the register y is further divided by 0.2 [/ rev.]. Therefore, finally, the value corresponding to y / Y in the equation (6) described above is stored in the register y.

In step 145, a value obtained by subtracting the value 1000 [rpm] of the engine speed at address 0 from the value in register m is stored in register m, as described above. Next, in step 146, the value of the register m is divided by the scale interval of the engine speed, 1000 [rpm], the integer part of the quotient is stored in the register m, and the remainder of the quotient is stored in the register x. The value of the register x is equal to the value x of the engine speed 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 address that is closest to the point that indicates the current engine condition and is below the point that indicates the current engine condition
For example, the row number of 0, 6, 12, 18 is defined as the first row). Then, in step 147, the value of the register x is further divided by 1000 [rpm]. Therefore, finally, the register x stores the value corresponding to x / X in the above equations (4) and (5).

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 four lower left corner addresses surrounding the current engine condition, that is, the address number of the nth address in FIG. 2 are obtained and stored in the register n.

In step 150, the learning delay amount θ _KG n stored at address n on the learning map is read out and stored in register A, and the learning delay amount θ _{KG (} n stored at address n + 1 is read.
₊₁₎ is read and stored in the register B, the learning delay amount θ _{KG (} n ₊₆₎ stored in the address n + 6 is read and stored in the register C, and the learning delay amount stored in the address n + 7 is read. The quantity θ _{KG (} n ₊₇₎ is read 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, and the value of register A is added to the value and stored in 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 the value and stored in register F. Finally, at step 153, register E
Is subtracted from the value in register F to be multiplied by the value in register y, and the value in register E is added to that value to obtain the learning retard angle 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.
Uses the register n of the two-dimensional interpolation routine of FIG.
First, in step 118, it is determined whether or not the corrected retard amount θ _K is 2 ° C. or more, as in the above. When the corrected retard angle θ _K is less than 2 ° C. A, the learning value α is set to −0.04 ° C. A at step 160 and the routine proceeds to step 162. When the corrected retard amount θ _K is 2 ° C. or more, it is determined in step 119 whether the corrected retard amount θ _K is 4 ° A or more. If the corrected retard amount θ _K is less than 4 ° C, the process returns to the main routine. If the corrected retard amount θ _K is 4 ° C or more, the learning value α is set to 0.04 ° C in step 161 and the process proceeds to step 162. move on. At 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. When the load is 0.6 or more, the engine speed N is the learning map lower limit value 1000 [rpm] in step 166.
If the load is less than 0.6, the engine speed N is 1000 [r.
pm] or less.

At step 166, the engine speed N is 1000 [rpm]
When it is determined that the learning delay amount θ _KG n is the learning delay amount θ _KG n previously learned at the address n in step 167.
Learning control is performed to add the learning retard amount θ _{KG (} n
Learning control is performed in which the learning value α is added to ( _+1), and the process returns to the main routine. As described above, the current engine speed N and load Q / N are Q / N ≧ 0.6 [/ re
v.] and N <1000 [rpm] exists, the value of the register n indicating the address of the RAM is 0 in the first line,
Since 6, 12, 18 can be taken, if a point indicating the current engine condition exists in the above area, 0 in step 167,
The learning delay amount at addresses 6, 12, and 18 is learning controlled, and the step
At 168, the learning retard amount of the addresses 1, 7, 13, and 19 is learning-controlled.

At step 166, the engine speed N is 1000 [rpm]
If it is determined that the learning retard angle θ _KG n previously learned at the nth address is the learning value α at step 169.
Learning control in which is added is performed. Points indicating the current engine conditions are Q / N ≧ 0.6 [/ rev.] And N ≧ 1000 [rp
m], the value of the register n indicating the RAM address can be from 0 to 23, and therefore all addresses are subject to learning control in step 169. Next step
At 170, it is determined whether the value of register n is not 23.
If the value of the register n is not 23, the values of the register n in step 171, step 173, and step 174 are respectively set.
It is judged whether it is not 17, whether it is 11, or not 5. 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 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 retardation amount θ _{KG (} n
_Perform learning control to add the learning value α to ₊₇₎ , and return to the main routine. Therefore, the value of register n is 1
When it is 7, 11, or 5, the learning delay amounts at addresses 17, 11, and 5 are respectively controlled to be learned in step 169, and the learning delay amounts at addresses 23, 17, and 11 on the next row are respectively controlled in step 178. Learning will be controlled.

When the value of the register n is neither 23, 17, 11 nor 5, in step 175, the learning delay amount θ _{KG (}
Learning control is performed in which the learning value α is added to (n ₊₁₎ . That is, the RAM obtained in step 149 of the two-dimensional interpolation routine
If the address of is not on the 6th line, the RAM obtained by the two-dimensional interpolation routine in steps 169 and 175.
The learning control is performed on the address No. and the address to the right of this address.
In step 176, it is judged whether or not the value of the 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 addresses of the RAM are 18 to 22 in the fourth column, the addresses stored in the register n and the addresses on the right side thereof are learning-controlled in steps 169 and 175. On the other hand, when the value of the register n is less than 17, that is, when there are four addresses surrounding the point indicating the current engine condition, step 177 is executed.
Learning control is performed by adding the learning value α to the learning delay amount θ _{KG (} n ₊₆₎ at the address n + 6. At step 178, the learning value α is added to the learning delay amount θ _{KG (} n ₊₇₎ at the address n + 7. Learning control for addition is performed. As a result, when there are four addresses surrounding the point indicating the current engine condition, the learning delay amounts of the above four addresses are learned and controlled in steps 169, 175, 177 and 178.

If the load is judged to be less than 0.6 [/ rev.] In step 162, the engine speed is 1000 [rpm] in step 163.
It is judged whether or not it is below, and the engine speed is 1000 [rpm]
In the following cases, 7 is subtracted from the value of the register n in step 165, and learning control is performed in step 178. The points indicating the current engine conditions are Q / N <0.6 [/ rev.] And N ≦ 1000.
When it is in the [rpm] area, the value of the register n becomes 0, so that the learning retardation amount of address 0 is learned and controlled in step 178 in this case. On the other hand, when the engine speed N exceeds 1000 [rpm], it is determined in step 164 whether the value of the register n is 5, and when it is not 5, 6 is subtracted from the value of the register n in step 179. , Steps 177 and 178 control the learning delay amount at addresses n + 6 and n + 7. When the value of register n is 5, step 180 subtracts 7 from the value of register n, and learning control is performed in step 178. The point that shows the current engine conditions is
When existing in the area of Q / N <0.6 [/ rev.] And N> 1000 [rpm], the value of register n can take the value of the address in the first column. Step 17
When the learning delay amount of the 5th address is learned and controlled by 8 and the value of the register n is 0, 1, 2, 3, 4, the addresses of the value of the register n and the addresses to the right of the register n are obtained in steps 177 and 178. The learning retard amount is learning-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 the learning retard amount θ _KG in the learning routine of FIG. 14 is updated by the learning control. Shown in.

Further, FIG. 15 shows changes in the corrected retard amount θ _K , the learned retard amount θ _KG , and the ignition timing θig with the passage of 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. In FIG. 16, the curves C _{1 to} C ₃ are the same as those in FIG. 3, and the correction delay angle θ _K is always constant regardless of whether knocking is likely to occur or not. To be understood.

As described above, according to the present invention, learning control is not performed when the correction delay amount is within the predetermined range, and thus knocking due to noise or the like can be excluded during learning control. As a result, it is possible to obtain an internal combustion engine in which fluctuations in ignition timing are small and torque fluctuations are small.

Further, since the update amount of the learning delay amount is set to be smaller than the update amount of the correction delay amount, the update speed of the correction delay amount can be increased and the responsiveness to the knock can be improved. Therefore, stable knocking control can be realized.

[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 ° C., and FIG. Flow chart of time coincidence interrupt A, FIG. 8 is a flow chart of time coincidence interrupt B, FIG. 9 is a flow chart of A / D completion interruption routine, FIG. 10 is a flow chart showing interruption routine every 4 msec, and FIG. FIG. 12 is a flow chart of a learning control routine, FIG. 13 is a flow chart of a two-dimensional interpolation routine, and FIG. 14 is a flow chart showing details of the learning routine.
FIG. 15 is a diagram showing changes in the corrected retard amount, the learned retard amount, and the ignition timing with the passage of time, and FIG. 16 is the same relationship between the engine speed and the ignition timing as in FIG. 3 and the corrected retard amount. FIG. 7 is a diagram showing the relationship between the learning delay amount and 2 ... Air flow meter, 12 ... Fuel injection valve, 18 ... Notting sensor, 32 ... Engine rotation angle sensor, 34 ... Electronic control circuit.

Front Page Continuation (72) Inventor Toshio Suematsu 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd. (56) References JP 56-23566 (JP, A) JP 57-105530 (JP, A)

Claims (2)

[Claims] Claims: 1. A basic ignition advance angle determined by engine speed and load, a retard correction amount for advancing the ignition timing when knocking occurs and for advancing the ignition timing when no knocking occurs, and a learning retard angle changed by learning control. In a knocking control method for an internal combustion engine, which calculates the ignition timing by subtracting the sum with the amount, when the corrected retard amount exceeds a preset predetermined range, the learning retard amount is retarded, When it is less than the range, the learning retard amount is advanced, and the update amount when retarding or advancing the learning retard amount is set to be smaller than the update amount of the correction retard amount. Control method for internal combustion engine. 2. The knocking control method according to claim 1, wherein the learning retard amount is stored in a memory in association with an operating region of the internal combustion engine.