JPS59103964A - Knocking control method for internal-combustion engine - Google Patents

Abstract

PURPOSE:In knocking control method where the firing timing is learning controlled in accordance to knocking strength, to stabilize the learning control amount by stopping learning control if correction lag angle is within predetermined range. CONSTITUTION:In steps 114, 115, current learning control amount thetakg is obtained. If it is decided in steps 118, 119 that the correction lagging angle thetak is within predetermined range, learning control is not performed. In other cases, learning control is performed in steps 120, 121. Consequently learning control amount is stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a knocking control method for an internal combustion engine, and particularly relates to a corrective retardation amount for performing retarding at a relatively fast speed depending on the presence or absence of knocking, and a method for controlling knocking at a relatively slow speed depending on the presence or absence of knocking. The present invention relates to a method for controlling knocking by retarding the basic ignition advance angle and correcting the basic ignition advance angle using a learned retard amount and K that are changed by learning control.

In the conventional knocking control method using learning control, the ratio of the engine rotation speed N1 to the intake air amount Q and the engine rotation speed N is Q/
Basic ignition advance angle θBA determined in advance by the load determined by N or intake pipe negative pressure! It is stored in the read-only memory (ROM) of the microcomputer in the form of a map, and the ignition advance angle θ to actually control the igniter is calculated based on the following equation (1), and this ignition advance angle is used to calculate the ignition advance angle θ. This is used to control knocking.

θ■ = θBASE (θKG + θx ) °゛Curve ° (1) However, θKG is a learning retardation amount that is determined by the engine speed, load, and K in order to keep the knocking level at a predetermined level, and is changed by learning control. , θ is a correction retard amount that retards the ignition timing when knocking occurs and advances the ignition timing when knocking no longer occurs.

Here, the corrected retard amount θ is determined as follows.

First, engine vibration is detected using a knocking sensor composed of a microphone, etc., and the engine vibration is increased to a predetermined times the average value (background) h of the engine vibration, l! + (where K is a proportionality constant) and the peak value α of engine vibration,
This peak value α and the value of K·b are compared. Peak value α
When the value of crab-b is exceeded, it is determined that knocking has occurred, and a correction delay is performed so that the ignition timing is delayed by a predetermined crank angle (for example, 0.4° CA) per occurrence of knocking, as shown in equation (2) below. The angle amount θxe is changed.

θ to ← θ to +0.4°CA ・・・・・・・・・・・・
・・・・・・・・・・・・ (2) Also, the peak value α, b
When the value is less than the value of ) The corrected retard amount θK is changed so that the ignition timing is advanced by a predetermined crank angle (for example, 0.08° CA).

To θ ← To θ -0.08°CA ・・・・・・・・・・・・
(3) Further, the learning retardation amount θKG according to the engine conditions is calculated as follows.

First, as shown in Fig. 1, engine speed N and load Q/
Addresses 0 to 23 where the learning delay angle amount is stored in correspondence with N.
The random access memory of a microcomputer (
(RAM) and create a learning map. A point (NXQ/N)'i that takes in the engine speed N and intake air amount Q and indicates the current engine condition on the learning Mazda
Find the RAM addresses of the four surrounding points.

Now, as shown in Fig. 2, the RAM address surrounding the point indicating the current engine state is rL (n-0, 1,...
(W
+ 1), learning retard amount θKG (rL+6
), and the learning retard amount θKG(rL+7) is stored at address l+7. Then, the difference in engine speed between addresses is 1tX, the difference in load between addresses is −+Y, and the difference in engine speed between address and the point indicating the current engine condition is x1. Assuming that the load difference ky between the point and the point shown is ky, the learning retardation amount θKG of the point showing the current engine state is determined by the two-dimensional interpolation method shown in equations (4) to (6) below.

The learning control of the learning map is performed as follows. First, a second timer that determines the learning control time depending on the current engine condition and a third timer that determines the learning control time regardless of the engine condition φ are prepared. The second timer sets the predetermined time (for example, 48 m5
When it is detected that e= ) has elapsed, the correction retard amount θK is changed to a predetermined crank angle (for example, 4° CA)
'i is exceeded, and when the corrected retard amount θK exceeds a predetermined crank angle, the learned retard amount of the four points on the learning map surrounding the point indicating the current engine condition explained above is determined. A predetermined crank angle (for example, 0.04° CA) is added.

As a result, the learning retard amount is learning-controlled so that the ignition timing is delayed. On the other hand, the third timer is set for a predetermined time (for example, 1
When it is detected that 6 seconds) have elapsed, a predetermined crank angle (for example, 0.01° CA) is subtracted from the learning retard amount of all addresses on the learning map, regardless of the presence or absence of knocking, so that the ignition timing is advanced. The learning delay amount is controlled by learning.

Using the corrected retardation amount θ changed as described above and the learning retardation amount KG obtained by the two-dimensional interpolation method from the learning map subjected to learning control, the above formula (1) is calculated. Based on this, the basic ignition advance angle θBAsIE is corrected to control knocking.

By the way, as shown in Fig. 3, the basic ignition advance angle θBAS
Ezunawachi M B T (Minimum 5park
Advance for Be5t Torque)
The ignition timing changes as shown by curve C according to the engine speed. Also, when knocking is less likely to occur, such as when the air is humid, the ignition timing at which slight knocking occurs is shown by curve C2.
When knocking is likely to occur, such as when the air is dry, the ignition timing at which minute knocking occurs is as shown by curve C8. Therefore, the ignition timing at which minute knocking occurs varies depending on the engine speed and environmental conditions.

In the above knocking control method using learning control,
When a predetermined period of time has elapsed, all learning retardation amounts are independently changed to the advance side by learning control, regardless of the presence or absence of knocking, so the learning retardation amount is changed in engine conditions where there are few opportunities for learning control on the retard side. There was a problem in that the amount was too advanced and knocking occurred. In addition, as mentioned above, since the learning retardation amount tends to be learned and controlled to the advance side, the learning control speed for controlling the ignition timing to the advance side cannot be set quickly, and as shown in Figure 3 above. When the engine conditions change and knocking becomes less likely to occur, as in the case shown in , the ignition timing may be retarded too much due to the learning retardation amount, and the best torque LA may not be achieved in the range where knocking does not occur. The problem was that there was no.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a knocking control method that can always perform knocking control in the same way under conditions where knocking is likely to occur and under conditions where knocking is unlikely to occur.

In order to achieve the above object, the configuration of the present invention changes from a basic ignition advance angle determined by engine speed and load to a basic ignition advance angle determined by engine speed and load and changed by learning control in order to bring the level of knocking to a predetermined level. A knocking control method for an internal combustion engine in which knocking is controlled by subtracting the sum of a learned retardation amount and a corrected retardation amount that retards ignition timing when knocking occurs and advances ignition timing when knocking no longer occurs. The learning retardation amount is changed so that the corrected retardation amount falls within a predetermined range. In the above configuration, it is preferable that learning control is not performed when the corrected retard amount takes a value within a predetermined range.

According to the configuration of the present invention, the learned retard amount is controlled to advance or retard so that the corrected retard amount falls within a predetermined range, for example, 2° CA≦θ and ≦4° CA. , there is no need to perform learning control on the advance side over a relatively long period of time (16 seconds) as in the past, and the speed of learning control on the advance side can be made as fast as the speed of learning control on the retard side. This prevents the ignition timing from being too late, and the once learned value is retained until the next time it is learned, reducing the occurrence of knocking. Programming is simplified because the conventional third counter program can be omitted. A unique effect can be obtained.

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

Further, an intake air temperature sensor 4 is provided near the air flow meter 2 to detect the temperature of intake air.

A throttle valve 6 is arranged downstream of the air flow meter 2, and a surge tank 8 is arranged 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 disposed protruding into the intake manifold 10. The intake 7-manifold 10 is connected to the combustion chamber 14A of the engine body 14, and is connected to the combustion chamber 14A of the engine body 14.
4A is connected via an exhaust manifold 16 to a catalytic converter (not shown) filled with a three-way catalyst. The engine body 14 is provided with a knocking sensor 18 configured with a microphone or the like and configured to detect vibrations of the engine.

Note that 20 is a spark plug, 22 is an oxygen sensor for controlling the air-fuel mixture to near the stoichiometric air-fuel ratio, and 24 is a cooling water temperature sensor for detecting 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 pickup and a signal rotor fixed to a distributor shaft.

This cylinder discrimination sensor 30 outputs a cylinder discrimination signal to an electronic control circuit 34 constituted by a microcomputer or the like, for example, every 720 degrees of crank angle, and this engine rotation angle sensor 32 outputs a cylinder discrimination signal, for example, every 30 degrees of crank angle. A reference position signal is output to the electronic control circuit 34.

The electronic control circuit 34, as shown in FIG.
Access memory (RAM) 36, read only memory (ROM) 38, and central processing unit (CPU)
40, 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. , ROM38, CPU40, CLOCK
41, first input/output boat 42, second input/output boat 4
4. First output port 46 and second output port 48
are connected to bus 50. The first input/output port 42 includes a buffer (not shown), a multiplexer 5
4. The air flow meter 2, the cooling water temperature sensor 24, the intake air temperature sensor 4, etc. are connected via an analog-digital (A/D) converter 56t. The multiplexer 54 and A/D converter 56 are controlled by a signal output from the first input/output port 42. The O sensor 22 is connected to the second input/output boat 44 via a buffer (not shown) and a controller 62, and a cylinder discrimination sensor 30 and an engine rotation angle sensor 32 are connected to the second input/output boat 44 via a waveform shaping circuit 64. It is connected.

Further, the knocking sensor 18 is connected to the second 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 66 receives a control signal output from the second input/output port 44 for inputting either the output of the peak hold circuit 61 or the output of the integrating circuit 63 to the A/D converter 68. is input to the peak hold circuit 61, and a reset signal is input from the second input/output port 44 to the peak hold circuit 61.

Further, the first output port 46 is connected to the igniter 28 via a drive circuit 70, and the second output port 48 is connected to the fuel injection device 12 via a drive circuit 72.

The ROM 38 of the electronic control circuit 34 stores in advance a map of the basic ignition advance angle θBASE expressed by the engine speed and intake air amount, the basic fuel injection amount, etc., and the signal from the air flow meter 2 and the engine rotation angle. The basic ignition advance angle and the basic fuel injection amount are successively determined by the signal from the sensor 32, and the basic ignition advance angle and the basic fuel injection amount are determined by various signals including the signals from the cooling water temperature sensor 24 and the intake air temperature sensor 4. A corrected ignition advance angle and a corrected fuel injection amount are added to the igniter 28 and the fuel injection valve 12 to control the igniter 28 and the fuel injection valve 12. 0. The air-fuel ratio signal output from the sensor 22 is used for air-fuel ratio control to control the air-fuel ratio of the air-fuel mixture to near the stoichiometric air-fuel ratio. Further, a 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 engine as described above will be described in detail. In addition, in explaining the present invention in detail, the main routines of fuel injection control, air-fuel ratio control, ignition timing control, etc. are the same as conventional ones, so the explanation will be omitted, and only the knocking control routine related to the present invention will be explained. explain.

FIG. 6 shows an interrupt routine every 30° CA when the present invention is implemented using a microcomputer. First, in step 81, the engine rotation speed N is determined from the rotation time based on the signal from the engine rotation angle sensor 32.
In step 82, the number of interruptions after the cylinder discrimination signal is input from the cylinder discrimination sensor 30 is counted, and a flag indicating the current crank angle is set. Next, step 83
, the flag set in step 82 is at top dead center (TD
It is determined whether the flag is C). If the current position is not the top dead center, the process proceeds to step 88, and if the current position is the top dead center, it is determined in step 84 whether or not the knock gate is closed. When the knock gate is open, the knock gate is closed in step 85, and when the knock gate is closed, the channel switching circuit 66 is switched in step 86, and the engine vibration signal output from the knock sensor 18 is passed through the band pass filter 60 and integrated. Al1 via the circuit 63 and channel switching circuit 66
) to converter 68 to begin A/D conversion of the average engine vibration value or background level. Subsequently, in step 87, the closing time t of the knock gate, that is, the next time to close the knock gate is calculated, and a time coincidence interrupt Af: is set.

Next, in step 88, based on the flag set in step 82, it is determined whether the crank angle has reached 90° CA# BTDC (before top dead center). Crank angle is 90°C
A If it is not BTDC, proceed to step 91,
In the case of °CA BTDC, the corrected advance angle amount θ is updated in step 89, and ignition timing calculation processing is performed (details of this will be explained below). Step 9
0, the time to turn on the igniter 28 is determined based on the ignition timing calculated in step 89 and the current time, and a time coincidence interrupt Bt is set, and an igniter-on flag is set. Then, in step 91, it is determined whether the crank angle has reached 600 CA BTDC,
If it is not 60°CA BTDC, return to the main routine, and if it is 60°CA BTDC, calculate the igniter off time in step 92, set time coincidence interrupt B, and set the igniter on time set in step 90. 7. Take down the rug.

Next, the time coincidence interrupt A shown in FIG. 7 will be explained.

This interrupt routine is for finding the peak value of engine vibration. When the time set in step 87 in FIG. 66 to the A/D converter 68 to start A/D conversion of the peak hold value, and then return to the main routine.

FIG. 8 shows the routine of time coincidence interrupt B, and the interrupt is performed when the time set in step 9o and step 92 of FIG. 6 comes. In step 94, it is determined whether the igniter on flag is set, that is, whether this flag is 1. If the flag is set, the igniter is turned on in step 96, and if the flag is off, the igniter is turned on in step 95. Turn off and return to the main routine.

FIG. 9 shows the Al1) conversion completion interrupt routine, and this interrupt is performed 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 the knock gate is currently open. When the knock gate is closed, in step 98 the A/D conversion value converted in step 86 of FIG. 6 is stored in the memory of kRAM 36 to set the background level to 6, and in step 99 the knock gate is opened and the process returns 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.
The peak value α is stored in the memory of the AM 36, and in step 101, the check 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 m5ec) for counting the time when no knocking occurs and the time for learning control. First, in step 102, a counter TIIV is used to calculate the time when knocking does not occur.
A counter TI ME increases the count value of IEI by 1 and calculates the time for learning control in step 103.
Increase the count value of 2 by 1. In the next step 104, the count value of the counter TIMEI is 12 (4
8rnsec) or less. If the count value exceeds 12, the count value of the counter TIMEI is set to 12 in step 105, and if the count value is 12 or less, it is determined in step 106 whether the count value of the counter TIMEI is 12 or less. to decide. Here, the count value is 1
When the count value exceeds 2, the count value of the counter TIME2 is set to 12 in step 107, 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 explained based on FIG. 11. When it is determined in step 88 of FIG. 6 that the crank angle has reached 90° CA BTDC, in step 108, the peak value α stored in step 100 of FIG. 9 and the peak value α stored in step 98 of FIG. The value obtained by multiplying the background level b by the constant K is
Compare with b. When the peak value α exceeds the value −bf, it is determined that knocking has occurred, and step 11
0, the correction retard amount θK is set to a predetermined angle (for example, 0.4°c
A] In step 112, the count value of the counter TIMEI, which counts the time during which knocking does not occur, is cleared. On the other hand, when the peak value α is less than or equal to h, it is determined that knocking does not occur, and in step 109, it is determined whether the count value of the counter TIMEI is greater than or equal to a predetermined value (12), and the count value is If it is equal to or greater than the predetermined value, it means that a state in which knocking does not occur has continued for a predetermined period of time, so in step 111, the corrected retard amount θKf: a predetermined angle (for example, 0.
08° CA), the counter TIME1ffi is cleared in step 112. Further, when the count value is D[not fixed value -] in step 109, the process advances to step 113. In step 113, the basic ignition advance is calculated using the corrected retard amount θ obtained as described above and the learned retard amount θKG obtained from the learning map using the two-dimensional interpolation method, as shown in equation (1). Ignition advance angle θitt that corrects the angle θBASE and actually controls the igniter
calculate.

Next, from the learning map,
A routine for determining M&retard amount θKG and performing learning control will be explained. FIG. 12 shows this routine from the middle of the main routine.

First, in step 114, the RAM addresses of four points surrounding the point indicating the current engine condition determined by the engine speed N and the load Q/N are found on the learning map. Next, in step 115, the two-dimensional sleeve spacing method (two-dimensional sleeve spacing method) is performed based on the takes stored in the four RAM addresses obtained, that is, the learning delay angle amounts stored in the four RAM addresses. The learning retardation amount θKG at the point indicating the current engine condition is calculated using a routine (the routine of which will be explained later), and the calculated value is stored in a memory location in the RAM. In step 116, it is determined whether or not the count value of the counter TIME2 for calculating the learning control time amount counted in step 103 in FIG. 10 is equal to or greater than a predetermined value (for example, 12). If the count value is less than a predetermined value, return to the main routine; if the count value is greater than or equal to the predetermined value, proceed to step 1.
After clearing the count value of the counter TIME2 in step 17, the corrected retard amount θK updated in steps 110 and 111 in FIG.
A) It is determined in step 118 whether or not it is greater than or equal to A).

If it is determined in step 118 that the corrected retardation amount θK is less than the first predetermined crank angle, then in step 121 the learning information stored in the four points on the learning map surrounding the point indicating the current engine condition is determined. Learning control is performed to subtract a predetermined crank angle (for example, 0.04° CA) from each retard amount, and the process returns to the main routine. As a result, when the corrected retard amount θK is less than the first predetermined crank angle, learning control is performed so that the learning retard amount of the learning map becomes smaller, and the ignition timing is controlled to advance by the learned retard amount. On the other hand, if it is determined in step 118 that the corrected retard amount θK is greater than or equal to the first predetermined crank angle, then in step 119 the corrected retard amount θK is set to a second value larger than the predetermined crank angle @1. A predetermined crank angle (e.g. 4°
CA). If it is determined in step 119 that the corrected retard amount θK is less than the first predetermined crank angle, that is, if the corrected retard angle h(θK satisfies the following conditions), the first predetermined crank angle (2 °CA)≦θK〈Second predetermined crank angle (4°CA) (7) Return to the main routine without learning control.

As a result, when the corrected retard amount θK takes a value within a predetermined range, learning control is not performed, and the ignition timing is not changed depending on the learned retard amount. Note that even when the corrected retard amount takes a value within a predetermined range, learning control may be performed as necessary. If it is determined in step 119 that the corrected retard amount θK is greater than or equal to the second predetermined crank angle, step 12
Performs learning control in which a predetermined crank angle (for example, 0.04° CA) is added to each of the learning retard amounts stored at four points on the learning map surrounding the point indicating the current engine condition at 0, Return to main routine.

As a result, when the corrected retard amount θK is equal to or greater than the second predetermined crank angle, learning control is performed so that the learning retard amount of the learning map becomes thicker, and the ignition timing is controlled to be delayed by the learned retard amount. .

By performing the learning control as described above, the learning retard cover of the learning map is changed so that the corrected retard amount falls within a predetermined range.

The learning routine shown in FIG. 12 will be explained in detail below.

FIG. 13 shows a detailed routine of the two-dimensional sleeve method of step 115 in FIG. 12. In this two-dimensional Soma routine, the entire map shown in Figure 1 is used as a learning map, and the four RAM addresses representing the current engine conditions are set as shown in Figure 2: L, L+1, L+6, Let +7. First, in step 130, the current load Q/
N is the upper limit of the load on the learning map, that is, 1.2 [t
/rev, make a full judgment as to whether it is less than or equal to E. load is 1
．． If it exceeds 2 (1/rev, :), 12 is stored in the register in step 131, and the load is set to 1.2.
(t/rev,] Step 13 if less than or equal to
4, the current load Q/N value is stored in register n. In step 135, the current engine speed N is equal to the upper limit of the engine speed on the learning map, that is, 6000 [r
, p, rn] or less. If the engine speed exceeds 6000 (γ, p, m'31r), 6000 is stored in register m in step 136,
If the engine speed is less than 6000 [τ, p, m], the current value of the engine speed N is stored in register m in step 137. In step 138, the value of the register is set to the lower limit of the load on the learning map, that is, 0.6.
(L/r, iv,) or more is determined, and if the register value is less than 0.6, step 139
In this step, the register value is set to 0.6, and if the register value is 0.6 or more, the process proceeds to step 140. Then, in step 140, the value of the register m is set to the lower limit of the engine speed on the learning map, that is, 1000 Cr,
P, m ) or more, and if the value of register m is less than 1000, in step 141 the value of register m is set to 1/register value 'z1000, and if the value of register m is 1000 or more, the next step 142 Proceed to.

As a result of the above, the current engine speed N and load Q/N
is a value on the learning map, that value is stored in register m
When the current engine speed N and load Q/N exceed the upper and lower limits of the learning map, the upper and lower limits are stored in registers m and 1, respectively.

Steps 142 to 149 are a routine for selecting four points on the learning map.

First, in step 142, the value obtained by subtracting the load value Q, 5 [t/rev,] at address 0 from the value of the register is stored in the register. Next, in step 143, the register value is set to 0, which is the load scale interval.
2 (t/rev, ), the integer part of the quotient is stored in the register, and the dark remainder is stored in the register y. The value of this register y is equal to the load value y from address 1 in FIG. 2 to the point representing the current engine condition. In addition, the integer part of the quotient stored in the register is the row of addresses closest to the point indicating the current engine condition and below the point indicating the current engine condition (horizontal arrangement of addresses, for example, addresses 0 to 5). The first column is the column number. Then, in step 144, the value of register y is further divided by 0.2 (1/rgv,).

Therefore, finally, register y contains y of equation (6) mentioned above.
A value corresponding to /Y is stored.

At step 145, the engine speed value ioo at address 0 is obtained from the value of register m, as described above.

The value obtained by subtracting (r, plm) is stored in register m. Next, in step 146, the value on the register door is set to 1000 (r, 7), 7, which is the scale interval of the engine rotation speed.
1Z), the integer part of the quotient is stored in register m, and the remainder of the song is stored in register X. The value of this register X is equal to the engine speed value X from address 9 in FIG. 2 to the point indicating the current engine condition. In addition, the integer part of the quotient stored in register m is the row of addresses closest to the point indicating the current engine condition and below the point indicating the current engine condition (vertical arrangement of addresses, e.g. 0.6
．． 12.18 is the first row). Then, in step 147, the value of register X is further increased by 1000 Cr, P, m). Therefore, in the end, register X contains (4), (
5) A value corresponding to x/X in the equation is stored.

Next, in step 148, the value of the register is multiplied by six and stored in the register, and in the next step 149, the value of the register and the value of register m are all added together and stored in the register. As a result, the addresses of the lower left corner of the four points surrounding the current engine condition, that is, the address number 7L in FIG. 2, are determined and stored in the register.

In step 150, the learned retard amount θKGrLfc stored at address 1 on the learning map is read out and stored in register A, and the learned retard amount θxa(+s+1) stored at address 1+1 is read out and stored in register B. The learning retardation amount θKG is stored in address +6.
(W+6) is read out and recorded in register C, and the learning retard amount θKG (tL+
7) is read and stored in register D.

Subsequently, in step 151, the value of register B is subtracted from the value of register A, the value of register X is multiplied, and the value of register A is added to the subtracted value, and the result is stored in register E. Also, in step 152, the value of register 1) is subtracted from the value of register C, and the value of register X is multiplied by
Then, add the value of register C to that value and write it to register F.
to be memorized.

Finally, in step 153, register E's 1
The value of register F is subtracted from 11, the value of register y is multiplied, and the value of register E is further added to that value to obtain the learning retard amount θKG at the point indicating the current engine condition.

Next, the detailed routine of steps 118 to 121 in FIG. 12 is shown in FIG. 14. Note that the register n in FIG. 14 is the register n of the two-dimensional sleeve routine in FIG. 13. First, in step 118, a full determination 1' is made as to whether the corrected retard amount θK is greater than or equal to 2°OA, as described above. When the corrected retard amount θK is less than 2°CA, the learned value αi−0,048CA is set in step 160.
As a result, the process proceeds to step 2 162. Correction retard amount θK is 2°
If it is equal to or greater than CA, it is determined in step 119 whether the corrected retard amount θK is equal to or greater than 4°CA. If the corrected retard amount θK is less than 4° CA, the process returns to the main routine, and if the corrected retard amount θK is 4° CA or more, the learned value α is set to 0.04° CA in step 161, and step 162 Proceed to. In step 162, the load Q/
Determine whether N is greater than or equal to the lower limit of the educational capital map, 0.6 [z/rgv, 1. If the load is 0.6 or higher, it is determined in step 166 whether the engine speed N is higher than the lower limit value i o o o [r, 7), 7Fl) of the learning map, and if the load is less than 0.6. If so, in step 163 the engine 11 rotation number N is 10.
00 [r, p, yn] Determine whether or not it is equal to or not.

In step 166, the engine speed N is 1000.
Cr, p, m), step 1
In step 67, a learning control is performed in which the educational fund value α is added to the previously learned learning retardation amount θKGft at address 11, and in step 168, the learning value is added to the learning retardation h10KG (7L+1) learned last time at address 11. Learning control is performed to add α, and the process returns to the main routine. Here, as shown above, the current engine speed N
and load Q/N is Q/N≧0.6 (: t /l'
eV, ) and N If the point indicating the problem exists in the above area, the learning delay amount of address 0.6.12.18 is controlled by learning in step 167, and in step 168, the learning delay amount of address 1.7.13.
The learning delay amount at address 19 is subjected to learning control 1.

In step 166, the engine speed N is 1000.
[If it is determined that r, p, m3 or more, learning control 1 is performed in step 169 in which the previously learned learning retard amount θ·9 learned value α at address fL is added. The point indicating the current engine condition is Q/N≧o, 6
[t/raw, ] and ≧1000Cr, p, m]
If the address exists in the area, the value of the register indicating the RAM address can take a value of θ to 23, so all addresses are subject to learning control in step 169. In the next step 170, it is determined whether the value of the register is not 23 or not. If the register value is not 23, it is determined whether the register value is not 17, 11, and 5 in steps 171, 173, and 174, respectively. The value of this register is 5
．． 11.17.23 represents the address on the 6th line.

When the register value is 23, the process directly returns to the main routine. The learning retardation amount at address 23 at this time is subjected to learning control in step 169. If the register value is 17.11.5, step 1
At 72, decrease the register value by 1 and proceed to step 1.
78, the learning delay angle θKc(rL+
7) performs learning control to add the educational capital value α, and then returns to the main routine. Therefore, when the value of the register is 17.11.5, step 169 determines that the register value is 17.11.5.
The learned angle of attack amounts at address 11.5 are each subjected to learning control, and in step 178, the learned angle retard amounts at addresses 23, 17, and 11 one column above are subjected to learning control.

When the register value is not 23.17.11.5, learning control is performed in step 175 in which the learning value α is added to the learning retard amount θxc(rL+1) at address +L+1. That is, if the RAM address obtained in step 149 of the 2-dimensional inter-axes routine is not on the 6th line, in steps 169 and 175, the RAM address obtained in the 2-dimensional inter-axes routine and this address are Learning control is applied to the right one and address 90. Step 17
6, determine whether the value of the register is less than 17.
If the value of the tiDI register is 17 or more, the process returns to the main routine. That is, when the RAM address is 18 to 22 in the fourth column, step 16
9 and step 175, the address stored in the register and the address to the right thereof are controlled to be learned. on the other hand,
When the value of V-distal is less than 17, that is, when there are four addresses surrounding the point indicating the current engine condition, in step 177, the learned retard amount θKG (
+L+6) is subjected to learning control that adds the learned value “total”,
In step 178, the learning delay amount θKG (TL
Learning control is performed to add the learning value α to +7). As a result, if there are four addresses surrounding the point indicating the current engine condition, step 169, step 175
, in step 177 and step 178, the above 4
The learning delay amount of each address is controlled by learning.

If it is determined in step 162 that the load is less than 0.6 [j/rev,'), it is determined in step 163 whether the engine speed is less than 1000 Cr,P,)rL), and the engine speed is If it is less than 1000 [r, p, m), 7 is subtracted from the register value in KH step 165, and learning control is performed in step 178. The point indicating the current engine condition is Q/N < 0.6 (t/rgv
, ) and N≦1000 (7', p, m) (7) When the current exists in the region, the register value is 0, so in step 178 in this case, the learning retard amount of the θ address is learned? 1ill III. On the other hand, if the engine rotation speed N is 1000 [r, P, m) e[,tiilt*KH, it is determined in step 164 whether the register value is 5 or not, and if it is not 5, the process is performed in step 17.
In step 9, calculate 6 increments from the register value, and in step 17
7 and step 178, address 6 and address 178 are
Learning delay angle 1rLk learning control at address 7.

When the register value is 5, 7 is subtracted from the register value in step 180, and learning control is performed in step 178. The point indicating the current engine condition is Q/
N< 0.6 (L/rsv,) KakN>100
0(?-, ρ1m), the value of the register can take the value of the address in the first column, so if the value of the register is 5, the learning slow I of address 5 is set in step 178.
The J amount is controlled by learning, and the register value is 0, ■, 2.3
．． 4, in steps 177 and 178, the learning delay amount of the address 1iIf of the register and the address to the right of it is controlled by learning.

Learning retardation amount θK in the learning routine shown in FIG. 14 above
Gf: The relationship between the conditions for the corrected Japanese angle amount θ when updated by learning control and the increase/decrease in the learning retardation amount θKG is summarized in the following table.

Figure 15 shows the changes in the corrected retardation amount θ, the learned retardation amount θKG, and the ignition timing θ increase over time. As can be seen from the figure, when the corrected retard amount θK is within a predetermined range, the learned retard amount θKG is constant, and when the corrected retard amount θK exceeds the predetermined range, the learned retard amount θKG is It increases, and decreases when the corrected retard amount θK is less than the desired range.

Furthermore, Fig. 16 shows the variation of ignition timing corresponding to the engine speed. In Fig. 16, curves 01 to C5 are
It is understood that the corrected retardation amount θK is always constant regardless of whether knocking is likely to occur or knocking is unlikely to occur.

As explained above, according to the embodiment of the present invention, since the %I control is not performed when the corrected retard angle Jd is within a predetermined range, the learned retard amount is stabilized and the fluctuation of one ignition timing, that is, the torque This has the effect of reducing fluctuations in .

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing the learning map, Figure 2 is an explanatory diagram showing a point indicating the current engine condition and the four points surrounding this point, and Figure 3 is a line indicating the relationship between engine speed and ignition timing. figure,
FIG. 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 flowchart of an interrupt routine every 30° CA, and FIG. Figure 8 is a flowchart of time coincidence interrupt A, Figure 8 is a flowchart of time coincidence interrupt B, Figure 9 is a flowchart of the A/D completion side input routine, Figure 10 is a flowchart showing the interrupt routine every 4 m5ec, and Figure 11 is a flowchart showing the interrupt routine every 4 m5ec. FIG. 12 is a flowchart of the learning control routine; FIG. 13 is a flowchart of the two-dimensional interpolation routine; FIG. 14 is a flowchart showing details of the learning routine; FIG. 15 is a flowchart of the learning control routine. A diagram showing changes in the amount of corrected retardation, amount of learning retardation, and ignition timing over time. Figure 16 shows the relationship between the engine speed and ignition timing, the amount of corrected retardation, and the amount of learning retardation, similar to Figure 3. FIG. 2... Air flow meter, 12... Fuel injection valve, 18... Sink sensor, 32... Engine rotation angle sensor, 34... Electronic control circuit. Agent Tatsuyuki Unuma (and 2 others) Figure 1 Figure 2 Figure 3 Kunzun ■ Transfer Figure 6 Figure 8 Figure 7 Figure 9 Figure 11 Figure 12 Figure 15
Day 9N1 Aoi TsukijE) /,,. Figure 16

Claims (2)

[Claims] (1) From the basic ignition advance angle determined by the engine speed and load, the learning retard amount and knock, which are determined by the engine speed and load and changed by learning control, are determined in order to bring the level of knock to a predetermined level. Decrease the sum of the correction retard amount that retards the ignition timing when knocking occurs and advances the ignition timing when knocking no longer occurs.
A knocking control method for an internal combustion engine that controls knocking, characterized in that the learning retardation angle amount is changed so that the corrected retardation amount falls within a predetermined range of values. . (2) A knocking control method for an internal combustion engine according to claim 1, characterized in that learning control is not performed when the corrected retardation amount takes a value within a predetermined range.