JPS59108872A - Method of controlling knocking of intenal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent unnecessary ignition lag by stopping a learning control while ignition timing is being controlled in accordance with engine operating conditions other than knocking. CONSTITUTION:In step 194, four points surrounding a point that indicates the present engine condition, are plotted on a learning map. In steps 195, 196, judgement is made whether or not the compensating quantity on cooling water temperature is stored in a RAM. When the compensating quantity is stored, a learning control is stopped since it is the time when an ignition timing control is carried out in accordance with the cooling water temperature. Thereby, the quantity of learning control is stabilized, preventing variation in ignition timing and unnecessary ignition lag.

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 correction retard 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 correcting a basic ignition advance angle by retarding the ignition angle and using a learning retard amount changed by learning control.

In the conventional knocking control method using learning control, the basic ignition advance angle θBASK' is determined in advance by the engine speed N, e, the ratio Q/N of the intake air mass Q and the engine speed N, or the load determined by the intake pipe negative pressure. i Microcombu, -
Store it in the read-only memory (ROM) in the form of a map, calculate the ignition advance angle θ1g that actually controls the igniter based on the following equation (1), and use this ignition advance angle to control knocking. 1.

01g=θBA8E −(θKG+θK) Song・・Song・
・(1) However, θKGit is a learning retard amount determined by the engine speed and load and changed by learning control in order to bring the level of knocking to a predetermined level, and θ is a learning retard amount that is determined by the engine speed and load and is changed by learning control. This is a correction retard amount that 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 average value (background) of engine vibration is multiplied by -1) (where k
is a proportionality constant) and the peak value a of engine vibration is determined, and this peak value a is compared with the value of -b. When the peak value a-b is exceeded, it is determined that knocking has occurred, and the ignition timing is delayed by a predetermined crank angle (for example, 0.4°GA) per knocking occurrence, as shown in the following equation (2). The correction retard amount θK is changed accordingly.

To θ←+0.4°GA to θ ・・・・・・・・・
・River... +21 Also, when the peak value a is below the value b, it is determined that knocking has not occurred, and the first
for a predetermined time (e.g. 43 m5ec) using a timer.
It is determined whether or not the elapsed time has elapsed, and when the predetermined time has elapsed, the predetermined crank angle (91, for example, 0.
08°CA) Change the corrected retard amount θK so that the ignition timing advances.

θ to ← θ to α08°CA...song...
・131 Also, learning retardation amount θKG according to engine conditions
is calculated as follows. First, as shown in Fig. 1, addresses θ to 23 for storing learning retard amounts in correspondence with engine speed N and load Q/N are prepared in the random access memory (RAM) of the microcomputer, and a learning map is created. Create. A point (N, Q/N) that takes in the engine speed N and intake air amount Q and indicates the current engine condition on the learning map - 4 points of RAM surrounding it
Find the address.

Now, as shown in Figure 2, the RAM address surrounding the current engine line 4,000'e is n (n = o, z, ・
------16), n+1. n+6, n4-7 is 6,
address n [learning retard amount θKGn, address n+1 is learning retard amount θKG ln+ 1), address n+6 is learning retard amount θ
KGln+61, learning delay amount θKaln+ at address n+7
71 are respectively stored. Then, the difference in engine speed between addresses X1 indicates the difference in load between addresses fY, and the difference in engine speed between address n and the point indicated by the current engine condition indicates the current engine condition at address X1. If the difference in load between the two points is y, then the learning retardation amount θKG of the point indicating the current engine condition can be 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 are all prepared. The second timer is set to a predetermined time (for example, 46 m5e).
c) When it is detected that the crank angle has elapsed, the corrected retard amount θK is changed to a predetermined crank angle (for example, 4°GA) i
When the corrected crank angle exceeds the predetermined crank angle, the learning retard amount θK is determined based on the learning retard amount at four points on the learning map surrounding the point indicating the current engine condition described above. Add the crank angle (for example, 0.04°ch).

As a result, the learning retard amount is learning-controlled so that the ignition timing is delayed. On the other hand, a third timer is used for a predetermined period of 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 θKG obtained by two-dimensional interpolation from the learning map subjected to learning control, the above (based on equation 11) is calculated. Knocking is controlled by correcting the basic ignition advance angle θBA81Ct.

Conventionally, in addition to the learning control described above, when the cooling water temperature is high, the cylinder inner wall temperature increases and knocking is likely to occur, so the ignition advance is increased by a predetermined crank angle. For this purpose, the ignition timing is advanced by a predetermined crank angle.

However, in such conventional knock control methods, learning control of the learning retard amount is performed when ignition timing control is performed according to engine cooling water temperature, so learning control is not performed under such engine operating conditions. If the engine operating conditions are such that the ignition timing is not controlled according to the engine coolant temperature after the engine cooling water temperature has been reached, knocking may occur, or if the amount of retardation during knocking control is increased, the output may decrease and fuel efficiency may decrease. There was a problem that deterioration occurred.

The present invention has been made to solve the above-mentioned problems, and even when the operating conditions change from the operating conditions in which ignition timing is controlled in accordance with engine operating conditions other than knocking to the operating conditions in which knocking is controlled, knocking does not occur. The overall purpose is to provide a knocking control method that performs learning control to prevent knocking from occurring.

In order to achieve the above object, the configuration of the present invention is to fully control the amount of retardation from the basic ignition advance angle determined by the engine speed and load according to engine operating conditions other than knocking, and to The learning retardation amount, which is determined by the engine speed and load and changed by learning control, in order to bring the knocking level to a predetermined level, delays the ignition timing when knocking occurs, and changes the ignition timing when knocking no longer occurs. In a knocking control method for an internal combustion engine, in which knocking is controlled by subtracting the sum of the learning retardation amount and the learning retardation amount, when ignition timing control is performed according to engine operating conditions other than the knocking, the learned retardation amount is This is designed to stop the learning control sound.

According to the configuration of the present invention, erroneous learning control is prevented, so a decrease in output and deterioration of fuel efficiency is prevented, and knocking does not occur even if the engine operating conditions change as described above. A unique effect can be obtained.

By the way, as shown in Fig. 3, the basic ignition advance angle θBAS
K or M B T (Minimum 5park
AdvanceFor Be5t Torgue)
changes like song 113Cs according to the engine speed. In addition, when knocking is difficult to occur, such as when the air is humid, the ignition timing at which slight knocking occurs is curve C.
2, and 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 C3. Therefore, the ignition timing at which minute knocking occurs varies depending on the engine speed and environmental conditions.

Therefore, in the conventional knocking control method using learning control as described above, when a predetermined period of time has elapsed, all of the learning retard angle amounts are independently changed to the advance side by learning control, regardless of the presence or absence of knocking. Under engine conditions where there are few opportunities for learning control on the retard side, the learning retard amount becomes too advanced, and there is a risk that knocking will occur. 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 Figure 2, the ignition timing may be retarded too much depending on the learned retardation amount, and the best torque may not be obtained in the range where knocking does not occur. There is a risk that it will not be possible.

Therefore, it is preferable that the learning control in the configuration of the present invention is performed so that the corrected retard amount falls within a predetermined range. In addition, engine operating conditions other than knocking include:
There are cases where the ignition timing is advanced while the air conditioner is operating.

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 as an intake air sensor is provided on the downstream side of the engine (not shown). The air flow meter 2 includes two compensation motion grates 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 IQ is detected as the voltage output from the potentiometer 2B. 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 IO is connected to the surge tank 8, and a fuel injection valve 12 is disposed to protrude 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 14A of the engine body 14.
4A is exhaust manifold 16 Kousuke 1. and is connected to a catalytic converter (not shown) filled with a three-way catalyst. The engine body 14 is provided with a knocking sensor 18, which is configured with a microphone or the like, and detects all vibrations of the engine. In addition, 20 is a spark plug,
22 is an 02 sensor for controlling the air-fuel mixture near the stoichiometric air-fuel ratio, and 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 3o 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 3o outputs a cylinder discrimination signal to an electronic control circuit 34 made up of a microcomputer or the like, for example, every 720 degrees of crank angle. The angular 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) 3B, and central processing unit (CPU)
) 40, ri l:I:, /ri ((:LOCK) 41, M 1 input/output boat 42, and second input/output boat 4
4, a first output boat 46, and a second output boat 48
RAM36, ROM38, CPU
40. CLOCK41, it.

The human output boat 42, the second input/output boat 44, the first output boat 46, and the second output boat 48 are connected to the bus 50.
connected by. The gt input/output boat 42 includes
Through a buffer (not shown), multiplexer 54, and analog-to-digital (A/D) converter 56, air flow meter 2, cooling water temperature sensor 24, and intake air temperature sensor 4 are connected.
etc. are connected. This multiplexer 54 and A
The /D converter 56 is controlled by a signal output from the first input/output port 42. Second input/output boat 4
4 includes a buffer (not shown) and a comparator 6
2, the sensor 22 is connected to the waveform shaping circuit 6.
4, a cylinder discrimination sensor 30 and an engine rotation angle sensor 32 are 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 set signal is input from the second input/output port 44 to the peak hold circuit 61. Further, the first output boat 46 is connected to the igniter 28 via a drive circuit 70, and the second output boat 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 basic fuel injection amount are read out based on the signals from the sensor 32, and various signals including those from the cooling water temperature sensor 24 and the intake air temperature sensor 4 are used to read out the basic ignition advance angle and the basic fuel injection amount. A corrected ignition advance angle and a corrected fuel injection amount are added to the basic ignition advance angle and basic fuel injection amount to control the igniter 28 and the fuel injection valve 12. The air-fuel ratio signal output from the 02 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. The learning control will be described with reference to the example in which the corrected retardation amount is within a predetermined range, and an example in which the ignition timing is retarded in accordance with the coolant temperature as an engine operating condition other than knocking will be described.

FIG. 6 shows an interrupt routine for every 39'CnA when the present invention is implemented using a microcomputer. First, in step 81, the engine rotation speed N is calculated from the rotation time based on the signal from the engine rotation angle sensor 32, and in step 82, the number of interruptions after the cylinder discrimination signal is input from the cylinder discrimination sensor 30 is counted. Sets a flag indicating the current crank angle. Next, step 8
3, in step 82 the standing t-coat flag is set to top dead center (
TDC) flag. 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. ,
A via the integrating circuit 63 and channel switching circuit 66
/D converter 68 to begin A/D conversion of the average value of engine vibration, ie, the background level. Subsequently, in step 87, the closing side t1 of the knock gate, that is, the next time to close the knock gate is calculated, and time-opening depth A is set.

Next, in step 88, the crank angle is set to 90° CABTDC (before top dead center) based on the flag set in step 82.
Judgment II is made to see if it has become. Crank angle is 90°CA
If not D T D C, proceed to step 91;
°CABTDC is adjusted in step 89 by updating the corrected advance angle θ and calculating the ignition timing (details of this will be explained below) in step 90.
Now, use the ignition timing calculated in step 89 and the current time to find the time to turn on the igniter 28, and set the time -
At the same time as setting the opening and opening B, the flag for Eve Knife On is set. Then, in step 91, it is determined whether or not the crank angle has reached 60° CABTDC.
If it is not CABTDC, return to the main routine, and if it is 60° CABTDC, calculate the igniter off time in step 92, set time-opening B, and set the evening knife on flag set in step 90. Take it down.

Next, the time-opening and opening 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 6B to start A/D conversion of the peak hold value, and then return to the main routine.

FIG. 8 shows the routine of time-spreading B, in which an interrupt is performed when the time set in step 90 and step 92 of FIG. 6 comes. In step 94, it is determined whether the even knife 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 down, the igniter is turned on in step 95. Turn off the igniter and return to the main routine.

FIG. 9 shows an A/D conversion completion interrupt routine, and this interrupt is performed when the background level A/D conversion and the peak hold value A/D conversion are completed. First, it is determined in step 97 whether or not 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.
Store in AM36 memory and set background level b
Then, 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 converted in step 93 of FIG.
/ The D conversion value is stored in the memory of the RAM 36 as the peak value a, the knock gate is closed in step 101, and the process returns to the main routine.

FIG. 10 shows an interrupt routine performed every predetermined time (for example, 4 mm) for counting the time when no knocking occurs and the time for learning control. First, in step 102, the count value of the counter MFil, which calculates the time when knocking does not occur, is increased by 1, and in step 103, the count value of the counter MB20, which calculates the time for learning control, is increased by 1.

In the next step 104, it is determined whether the count value of the counter TIMEI is less than or equal to 12 (48m5ec). If the count value exceeds 12, the count value of the counter TIMEt 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 color/time2 is 12 or less. . Here, if the count value exceeds 12, in step 107, the counter TIMT! The count value of 2 is set to 12 and the process returns to the main routine, and the count value is 12 or less.

Sometimes it returns to the main routine.

Next, the detailed route 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° CABTDC, step 122 determines whether the load is 0.6 [l/rev] or more.
In other words, it is determined whether or not the knocking control area is reached. If it is not in the knocking control region, the basic ignition advance angle θBA81C is set to 01g in step 123, and if it is in the knocking control region, in step 108, the peak value a stored in step 100 in FIG. The value obtained by multiplying the background level b stored in step 98 by a constant k is compared with -b. The peak value a is the value k
l), it is determined that knocking has occurred, and in step 110 the correction retard amount θK is increased by a predetermined angle (by 0.4° CA), and in one step 112, the time during which knocking does not occur is determined. Clear the count value of the counter MFII. On the other hand, when the peak value a is equal to or greater than the value ktl, it is determined that knocking does not occur, and in step 109, it is determined whether the count value of the °C counter MKt is equal to or greater than a predetermined value (12), and the When the value is greater than or equal to 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 correction retard amount θK is determined.
After decreasing by a predetermined angle (if!l, o, o s'CA), the counter TIME1 is cleared in step 112. Further, if the count value is less than the predetermined value in step 109, the process proceeds to step 125. In step 125, the advance angle amount θ is calculated according to the following equation (7), and then the process proceeds to step tta.

θ←θBAE! I-θHOT+θC0LD...
(7) However, θHOT is a correction value for the advance angle amount when the cooling water temperature is high, and θC0LD is a correction value for the advance angle amount when the cooling water temperature is low to -. These correction values θHOT.

The calculation routine for θC0LD will be explained later.

In step 113 described above, the second medical school advance angle 01g is calculated from the corrected retardation amount θ obtained as described above and the learning map.

Next, a routine for determining the learning retardation amount θKG corresponding to the current engine condition from the learning map and performing learning control will be explained. FIG. 12 shows this routine from the middle of the main routine.

First, in step 124, it is determined whether or not the knocking control region is reached based on the load. If it is not the knocking control region, the process proceeds to the main routine, and if it is in the knocking control region, the engine speed N and the load Q are determined in step 114.
4 surrounding the point indicating the current engine condition determined by /N.
Find the RAM address of the point on the school funds map. Next, in step 115, a two-dimensional interpolation method (two-dimensional interpolation method (The routine will be explained later) calculates the learning retardation amount θKG at the point indicating the current engine condition, and stores the calculated value in a predetermined location in the RAM.

In step 116, a counter TI is used to obtain the learning control time counted in step 103 in Fig. 1θ.
It is determined whether the count value of ME2 is greater than or equal to a predetermined value (for example, 12). If the count value is less than a predetermined value, the process returns to the main routine, and if the count value is greater than or equal to the predetermined value, the count value of the counter TIMIlj2 is cleared in step 117, and then updated in step 110 and itt in FIG. In step 11B, it is determined whether the corrected retard amount θK is equal to or larger than a first predetermined crank angle (for example, 2° CA).

If it is determined in step 118 that the corrected retardation amount θK is less than the first predetermined crank angle, it is stored in four points on the learning map surrounding the point indicating the current engine condition in step 121 (S Learning control is performed to subtract a predetermined crank angle (for example, 0.04° CA) from each learning 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 learned retard amount of the learning Mazda 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 ttS that the corrected retard amount θK is equal to or greater than the first predetermined crank angle,
In step 119, it is determined whether the corrected retardation amount θK is less than a second predetermined crank angle (for example, 4° CA) that is greater than the first predetermined crank angle. Step 1
In step 19 (), if it is determined that the corrected retard amount θK is less than the first predetermined crank angle, that is, if the force is applied to the corrected retard amount θ and the following conditions are satisfied, the predetermined crank angle ( 4°CA) 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 1
At step 20, learning control is performed to add a predetermined crank angle (for example, 0.04° CA) to each of the learning retard amounts stored at the four points on the learning map surrounding the point indicating the current engine condition, and the main routine Return to.

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 larger, and the ignition timing is controlled to be delayed by the learned retard amount.

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

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

FIG. 13 shows a detailed routine of the two-dimensional interpolation method of step ttS in FIG. 12. In this two-dimensional interpolation routine, the map shown in Figure 1 is used as a learning map, and the four RAM addresses representing the current engine conditions are determined as n, n + l, n + 6, and n + 6 as shown in Figure 2. n
The score shall be 4-7. First, in step 130, it is determined whether the current load is less than the upper limit of the load on the Q/NIJ' learning map, that is, 1.2 (1/rθv,). If the load exceeds 1.2 (J/rev, ), store 1.2 in register n in step tat, and if the load is less than 1.2 C-t/rθV. At 134, the current load Q/N value is stored in register n. In step 135, the current engine speed N is the upper limit of the engine speed on the learning Mazda, which is 6000.
(r, p, m,: Determine whether or not it is 3 or less. If the engine speed exceeds 6000 [rpm], 6000 is stored in register m in step 136, and the engine speed is set to 6000 [rpm]. (rpm) or less, the value of the current engine speed N is stored in register m in step 137. In step 13B, the value of register n is set to the lower limit of the load on the learning map, that is, 0.6 [t /
rθ■] or more, and if the value of register n is less than 0.6, the value of register n is set to 0.6 in step 139, and if the value of register n is 0.6 or more, the value of register n is set to 0.6. Step 14. OK proceed.

In Stella 1140, the value of register m is the lower limit of engine rotation speed on the learning mag, that is, 1ooo(rp
m) Determine whether or not the value is greater than or equal to the value of register river 10.
If the value is less than 00, the value of the register m is set to tooo 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 of the above, when the current engine speed N and load Q,/N are values on the learning map, those values are stored in registers m and n, respectively, and the current engine speed N and load Q/N are When the upper and lower limits of the learning map are exceeded, the upper and lower limits are stored in registers m and n, respectively.

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

First, in step 142, the value obtained by subtracting the load value o, 61:t/rθv]° at address 0 from the value of register n is stored in register n. Next, in step 143, the value of register n is set to 0, 2 [ψ
θV], 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 y is equal to the load value y from address n in FIG. 2 to the point representing the current engine condition. In addition, the integer part of the quotient stored in register n is the column of addresses closest to the point indicating the current engine condition and below the point indicating the current engine condition (horizontal sequence of addresses, e.g. 0 to 5). The first column is the address sequence).

Then, in step 144, the value of register y is further divided by 0.2 (j/rev,). Therefore, finally register y has Plr1 as 7/ of equation (6) mentioned above.
A value corresponding to Y is stored.

In step 145, the value of the engine rotational speed at address O is calculated from the value of register m, as described above.

The value obtained by subtracting (rp, m ) is stored in register m.

Next, in step 146, the value of register m is set to 1 000 (r, p, m
), the integer part of the quotient is stored in register m, and the remainder of the quotient is stored in register X.

The value of this register X is equal to the engine speed value X from address n 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, for example, 0.6, The first row is the sequence of addresses I2.18).

Then, in step 147, the value of register X is further divided by too(r-nm). Therefore, the value corresponding to x/X in the above-mentioned equations (4) and (5) is finally stored in register X.

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

In step 150, the learning retard amount θKGn stored at address n on the learning map is read out from the register A.
The learning delay angle θ stored at address n+1
xatn-zl is successively stored in register B, and n+
Learning retardation amount θKGln+fil stored at address 6
is read out and stored in register C, and the value of learning retard amount register B stored at address n+7 is subtracted, multiplied by the value of register Let E memorize it. Also, step 152
Then, 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 this value, and the result is stored in register F. Finally, in step 153, the value of register F is subtracted from the value of register E, multiplied by the value of register y, and the value of register E is added to that value to learn a point indicating the current engine condition. Let the retard amount be θKG.

Next, a detailed routine from step ttS to step 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 interpolation routine in FIG. 13. First, in step ttS, it is determined whether the corrected retard amount θK is equal to or greater than 2° CA, as described above. When the corrected retard amount θK is less than 2° CA, the learned value α is set to −0.04° CA in step 160, and the process proceeds to step 162. Correction retard amount θK is 2°CA
In the above case, in step 119, the correction retard angle mθ
Determine whether K is greater than or equal to 4° CA. If the corrected retard amount θK is less than 4°ch, return to the main routine, and if the corrected retard amount θK is 4°CA or more, set the learned value α to 0°04'CA in step 161 and proceed to step 162. move on. In step 162, it is determined whether the load Q/N is greater than or equal to the learning map's T'' limit value 0.6 (j/rev,':1. If the load is greater than or equal to 0.6, in step 166 It is determined whether the engine speed N is equal to or higher than the lower limit of the learning map (1oooCr, pm), and if the load is less than 0.6, step 1
At 63, the engine speed N is t o o o [:
r, p, m) or less.

In step 166, the engine speed N is 10 o
o (r, p, m), in step 167 learning control is performed in which the learning value α is added to the previously learned learning retard amount θKGH at address n, and in step 168 The learning delay angle θxa ln+ 11 is the learning value α that was learned last time at the address.
A learning control is performed in which the value is added, and the process returns to the main routine. Here, as mentioned above, the current engine speed N and load Q/N are Gl/N22.6 [
j/rev,] and N<too(r, p, m), register n indicating the address of RAM.
Since the value of can take the value 0.6.12.18 in the first row, if a point indicating the current engine condition exists in the above region, the 0.6.12.18 point is learned in step 167. The amount of retardation is controlled by learning, and in step 168 1.7.13.
The learning retardation amount of the 19 points is controlled by learning.

In step 166, the engine speed N is 1ooo (
rpm) or more, in step 169, the previously learned learning retard amount θKG at address n is determined.
Learning control is performed in which a learning value α is added to . The point indicating the current engine condition is Q/N22.6 (j/r
ev ) and N22000 (rpm: 1), the value of register n indicating the RAM address is θ~
23, all addresses are subject to learning control in step 169. In the next step 170, it is determined whether the value of register n is not 23 or not. If the value of register n is not 23, it is determined in step 171, step 173, and step 174 whether the value of register n is not 17, 11 (or resultant), and 5, respectively. The value of this register n is 5, tt, t
';r, 23 represents the address of the 6th line. When the value of register n is 23, the process directly returns to the main routine. At this time, the learning retardation amount for the 23 locations is subjected to learning control in step +69. register n
When the value of is 17, tt, S, the value of register n is decreased by 1 in steps 172 to 9, and step 178 is performed.
The learning delay angle θK a (n +
Learning control is performed to add the learning value α to 71, and the process returns to the main routine. Therefore, the value of register n is 1
7.11.5, step 169 sets 17.1.
The learning retard amounts for address 1.5 are each subjected to learning control, and in step 178, the learning retard amounts for address 23.17.11 one column above are subjected to learning control.

When the value of register n is not 23.17.1115, learning control is performed in step 175 in which n+ is added to the learning retard amount θKGtn+1) of the address and the learning value α. That is, when the RAM address obtained in step 149 of the two-dimensional interpolation routine is not on the sixth row, the second
Learning control is performed on the RAM address obtained by the dimensional interpolation routine and the address to the right of this address. In step 116,
It is determined whether the value of register n is less than 17, and if the value of register n is 17 or more, the process returns to the main routine. In other words, the RAM address is 18 in four columns.
~22, step 169 and step 1
At 75, the address stored in register n and the address to the right of the address are subjected to learning control. -10,000, the value of register n is 1
If it is less than 7, that is, there are four addresses surrounding the point representing the current engine condition, step 177
Then set the learning value α to the learning delay amount θKG(n+6) at address n16.
Learning control is performed to add n+ in step 178.
Learning control is performed in which the learning value α is calculated by the learning retardation amount θKG (n+7) at 7 m ground. As a result, when there are four addresses surrounding the point indicating the current engine condition, the learning retard amounts of the four addresses are learning-controlled in steps 169, 175, 177, and 178. .

If it is determined in step +62 that the load is less than 0.6 Ci/rev, it is determined in step 163 whether the engine speed is 3 or less. In step 165, subtract 7 from the value of regimen 7n, and in step 1
Learning control is performed at 78. The point indicating the current engine condition is Q/N (0,6 (1/rev:] force・tsuN≦1
000 (rpm), the value of register n is O, so in this case Q) Step 17
At No. 8, the learning delay amount at address 0 is subjected to learning control. On the other hand, when the engine speed N exceeds 1000 [rpm], the Stellar Two 164 judges whether the value of the register n is 5 or not. Subtract 6 from direct,
n+Ft at step turtle 77 and step 178
The learning delay amount of the address and n+7 address is controlled by learning. Furthermore, when the value of register n is 5, 7 is subtracted from the value of register n in step 180, and learning control is performed in stellar 1178. The point indicating the current engine condition is Q/
N (0,6(i/rev) and N) 100
o[:r-pm], the value of register n can take the value of the address in the first column.
When the value of is 5, the learning delay amount at address 5 is controlled by learning in step 17B, and the value of register n is 0, 1, 2, 3, 4.
In this case, in Step 1F7 and Step 178, the learning delay amount of the address of the value of register n 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
The following table summarizes the relationship between the conditions for the corrected retard angle -1θ when G is updated by learning control and the increase/decrease in the learned retard amount θKG.

Further, FIG. 15 shows changes in the corrected retard amount θ, one learning retard angle θKG, and the ignition timing 01g over time. As can be understood from the figure, when the corrected retard amount θK is within a predetermined range, the learned retard amount θKG is constant, and the corrected retard amount θI
When ( exceeds the predetermined range), the learned retard amount θKG increases, and when the corrected retard amount θK is less than the predetermined range, it decreases.

Furthermore, FIG. 16 shows the variation in ignition timing corresponding to the engine speed. In FIG. 16, the curves C0 to C8 are the same as those in FIG. 3, and it is understood that the corrected retardation amount θK is always constant whether knocking is likely to occur or knocking is unlikely to occur. .

Next, the main routine for calculating the advance angle correction values θHOT, θcot, and o''l based on the engine cooling water temperature will be explained using FIG.

I'll leave it there. In creating this map, since knocking is more likely to occur as the cooling water temperature is higher, the correction sound on the high temperature side is made small and the correction amount on the low temperature side is made large. In steps tst, t8a, 185, it is determined in which range of water temperatures W1, W, . . . W on the map the current water temperature T falls. When T≦W, the correction amount θ is set as the correction value θCoLD in step 182, and when W, (T≦W, the correction value is calculated by interpolation using the following equation (8) in step +84. Calculate θC0LD and proceed to step 190.

Then, the process proceeds to step 190. If WI≦T, the correction value θC0LD is set to 0 in step +89 and the process proceeds to step 190. In step 190, the current figure 19 is
The routine for determining whether or not to perform learning control is shown from the middle of the main routine. In step 194, four points surrounding the point indicating the current engine condition are found on the learning map, and in steps 195 and 196, it is determined whether or not the correction amounts θC0LD and θHOT regarding the cooling water temperature are not O, that is, they are found using the routine shown in FIG. It is determined whether the correction amount is stored in the RAM. Correction amount θC
0LD.

If either θHOT is stored, the ignition timing is controlled according to the cooling water temperature, so the process proceeds to the next routine without learning control and the correction amount θC0LD is performed.
, θHOT are not stored, in step 197, learning control is performed on the four points surrounding the point indicating the current engine condition as described above, and the process proceeds to the next routine.

As explained above, according to the above embodiment of the present invention, learning control is not performed when the corrected retard amount is within a predetermined range, so that the learned retard value is stabilized and fluctuations in ignition timing, that is, fluctuations in torque, are prevented. This has the effect of reducing the amount of

In addition, in the above embodiment, the case where the corrected retardation amount is controlled within a predetermined range as learning control has been described, but the present invention is not limited to this, and the present invention is not limited to this, and the present invention is not limited to this. It can be used.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing the learning Mazda, Figure 2 is an explanatory diagram showing a point indicating the current engine condition and 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 A/D completion side input routine, and Figure 10 is a flowchart showing an interrupt routine every 4m (8). Figure 12 is a flowchart of a routine for updating the correction retardation amount, Figure 12 is a flowchart of a learning control routine, Figure 13 is a flowchart of a two-dimensional interpolation routine, Figure 14 is a flowchart showing details of the learning routine, and Figure 15. is a diagram showing changes in correction retardation amount, learned retardation amount, and ignition timing over time;
Fig. 16 is a diagram showing the relationship between the engine speed and ignition timing, the corrected retard amount, and the learned retard amount, similar to the stripe 3 chart, and Fig. 17 is a map of the correction amount θC0LD due to cooling water temperature and pressure. FIG. 18 is a flowchart of a routine for calculating the correction amount based on the cooling water temperature, and FIG. 19 is a flowchart of a routine for determining whether or not to perform learning control. 2... Air flow meter, +2... Fuel injection valve, 1
8...Knocking sensor, 32...Engine rotation angle upper sensor, 34...Electronic control circuit. Agent Tatsu Unouma Nogo 1 ■X Chive 62 Figure 1 Figure 2 Figure 3 Figure 1 Shijishi round ＼ Figure 18 Figure 19

Claims (1)

[Claims] (1) In addition to controlling the amount of retardation from the basic ignition advance angle determined by the engine speed and load according to engine operating conditions other than knocking, the level of knocking is controlled from the basic ignition advance angle to a predetermined level/l/l. The learning retard amount is determined by the engine speed and load and is changed by learning control in order to increase the engine speed, and the correction retard is used to retard the ignition timing when knocking occurs and to advance the ignition timing when knocking no longer occurs. In the knocking control method for an internal combustion engine, in which knocking is controlled by subtracting the sum of the learning retardation amount and the ignition timing control according to engine operating conditions other than the knocking, the learning control of the learning retardation amount is performed. A knocking control method for an internal combustion engine characterized by stopping the engine.