JPS59136574A - Knocking control of internal-combustion engine - Google Patents

Abstract

PURPOSE:To obtain the optimum ignition timing quickly when an engine condition is transferred into a control area by a method wherein a correcting delay angle upon the time of transfer, in which the engine condition transfers into the non- control area of knocking, is memorized and maintained. CONSTITUTION:An electronic control circuit 34 dicides by the ratio of an air volume Q, sensed by an airflow meter 2, and a revolving signal N, detected by a sensor 32, at a predetermined crank angle whether an engine condition is in the knocking control area or not. If the engine codition is in the control area and the generation of knocking is detected by the signal of a knock sensor 18, knocking is controlled by subtracting the sum of the corecting amount of delay angle and the amount of learning delay angle from a basic spark advance. When the engine condition is transferring into the non-control area, the amount of correcting delay angle upon the transfer is memorized and maintained, while the knocking control is effected by utilizing the memorized and maintained amount of correcting delay angle at the initial stage in which the engine condition is transferred into the control area again. Thus, the optimum ignition timing may be obtained and the knocking will never be generated.

Description

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

The conventional knocking control method using learning control is based on the engine rotational speed N, the ratio Q/ of the intake thrust amount Q and the engine rotational speed N.
The basic ignition advance angle θBASE, which is predetermined by the load determined by N or intake pipe negative pressure, is stored in the read-only memory (ROM) of the microcomputer in the form of a map, and the igniter is actually activated based on the following equation (1). The ignition advance angle θ12 to be controlled is calculated, and knocking control is performed using the ignition advance angle θ12. Further, in a light load region such as during idle linking, knocking does not occur, so knocking control is not performed, and the corrected retard amount is set to zero and ignition is performed using the basic ignition advance angle.

θif=θBASE−(θKG+θK)・・・・・・
(1) However, θKG is the learned retard amount that is determined by the engine speed and load and is changed by learning control in order to bring the knocking level to a predetermined level, and θ is the learning retardation amount that is changed by learning control when non-king occurs. 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, the engine vibration is detected using a knocking sensor consisting of a microphone, a microphone, etc.

A predetermined times the average value (background) b of engine vibration, b (where k is a proportionality constant), and a peak value a of engine vibration are determined, and this peak value a is compared with the value of b. When the peak value a exceeds the value of -b, it is determined that knocking has occurred, and the crank angle is set at a predetermined crank angle (for example, 04℃A-) per knocking occurrence, as shown in the following equation (2).
The corrected retard amount θK is changed so that the ignition timing is delayed.

θ ← θ +04°C A... (2) Determine that no ticking has occurred, and use the first timer to determine whether a predetermined time (for example, 48m5ec) has elapsed;
``When a predetermined time has elapsed, the corrected retard amount θK is changed so that the ignition timing advances by a predetermined crank angle (for example, 008° C.A.) as shown in the following equation (3).

θ to ← θ to -0.08℃A... (3) It's a sword.
The learning retardation amounts 19y and 19c depending on the engine conditions are calculated as follows. As shown in Fig. 1, the addresses 0 to 23 for storing the learning retardation amount in correspondence with the engine speed N and the load Q/N are stored in the microcomputer's access memory (RAM). Prepare and create a learning map.

The engine speed N and intake air amount Q are taken in, and a point (N, Q/N
) to find the RAM addresses of the four points surrounding it.

Now, as shown in Fig. 2, the addresses of R and AM surrounding the point indicating t4 of the current engine are n (n=0.1.,...
...16), n+1, n+6, n+7,
Learning retard amount θKGn at address n, learning retard amount θKG (n+1) at address n+1, learning retard amount θKG at address n+6
(n+6), learning retard amount θKG (n+7) at address n+7
) are respectively memorized. Then, the difference in engine speed between addresses is X, the difference in load between addresses is Y, the difference in engine speed between address n and the point indicating the current engine condition is X, and the difference between address n and the current engine If the difference in load between the points indicating the conditions is y, then the current engine moat 1. The learning retardation amount θKG of the point indicating r is determined.

X(θKG+θKc(n+1)) A= +θK
G n... (4)X(θKG(n+6)−θKG
(n+7))B=□+θKG(n+fi)...(And the learning control of the above learning map is performed as follows.First, the learning control time is determined according to the current engine conditions. 2 and a third timer that determines the learning control time regardless of whether the engine freezes or not. A second timer is used for a predetermined period of time (for example, j8 m
5ec), when it is detected that the corrected retardation amount θK is changed to a predetermined crank angle (for example, 4℃A)
When the corrected retardation amount θK exceeds a predetermined crank angle, a predetermined learning retardation amount is applied to the four points on the learning map surrounding the point indicating the current engine condition explained above. Add the crank angle (for example, 0.04°C A). 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, 155
ec) When it is detected that the ignition timing has elapsed, the ignition timing is advanced by subtracting a predetermined crank angle (for example, OO1℃A) from the learning retardation amount of all addresses on the learning map, regardless of the presence or absence of knocking. The learning retardation amount is controlled as follows.

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

However, in the conventional knocking control method, as mentioned above, a knocking non-control area is provided at light loads below a predetermined load, such as during idling, and the correction retard amount is set to zero in this non-king non-controlling area. Therefore, when the engine conditions change from a knocking non-control area to a knocking control area, learning control is performed so that the learning retardation amount is small because the corrected retardation amount is small. There was a problem in that knocking occurred, which adversely affected the engine, and the learning retardation amount learned last time on the light load side was changed.

The present invention has been made to solve the above problems, and provides a knocking control method for an internal combustion engine in which when engine conditions change from a non-knocking control region to a knocking control region, the optimum ignition timing is immediately adjusted to prevent knocking from occurring. The purpose is to provide.

In order to achieve the above object, the present invention is configured such that, in a conventional knocking control method for an internal combustion engine, a correction retardation amount at the time of transition to a non-engine control region is memorized and held. As a result, knocking control is performed using the previously stored corrected retardation amount at the initial stage when the engine condition shifts from the knocking non-control region to the knocking control region.

According to the configuration of the present invention, when the engine condition transitions from the knocking non-control area to the knocking control area, the correction retard amount at the time of transition from the knocking control area to the knocking non-control area, that is, the learning controlled learning. Since the non-king control is started from the corrected retardation amount that matches the retardation amount, a unique effect is obtained in that knocking does not occur and erroneous learning control is not performed.

Still, as shown in FIG. 3, the basic ignition advance angle θBASE, that is, M
dvancefor Be5t Torque) changes as shown in curve C7 according to the engine speed, and when knocking is difficult to occur, such as when the air is humid, the ignition timing at which slight knocking occurs changes as shown in curve C2,
The ignition timing at which slight knocking occurs when knocking is likely to occur, such as when the air is dry, is as shown by curve c3, and the ignition timing at which slight knocking occurs varies depending on the engine speed and environmental conditions. Therefore, in the above configuration of the present invention, in order to control knocking in the same way under operating conditions where non-king is likely to occur and operating conditions where knocking is unlikely to occur, the correction retard amount is set within a predetermined range in learning control within the non-king control region. (For example, 2℃A≦θ≦
It is preferable to change the learning retardation amount to a value of 4° C.A).

Next, FIG. 4 shows an example of an engine to which the present invention is applied. As shown in the figure, this engine is
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 two compensation plates that are rotatably provided in the damping chamber and a potentiometer 1 that detects the opening degree of the compensation plate 12A.
'2B. Therefore, the amount of intake air. is detected as the voltage output from the potentiometer 2B. Still, an intake air amount sensor 4 is provided near the air flow meter 2 to detect the temperature of intake air.

A throttle valve ℃ 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 1o is connected to the surge tank 8, and a fuel injection valve 12 is disposed to protrude into the intake manifold 1o. Ear 7- The manifold IO is connected to the combustion chamber 14A of the engine body 14, and the combustion chamber 14A of the engine is connected to a catalytic converter (not shown) filled with a three-way catalyst via the exhaust manifold 16. . The engine body 14 is provided with a knocking sensor 18 that is configured with a microphone or the like and detects vibrations of the engine. In addition, 2o is a spark plug, and 22 is an o2 used to control the air-fuel mixture to near the stoichiometric air-fuel ratio.
The sensor is a cold/hot water temperature sensor that detects the engine coolant temperature.

The spark plug 2 (1:) of the engine body 14 is connected to a distributor 26, and the distributor 26 is connected to an igniter 28. , a cylinder discrimination sensor 30, and an engine rotation angle sensor 32 are provided.

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 the g-th
Access memory (RAM) 36, read-only memory (R, OM) 38, and central processing unit (CPU)
40, a clock (CLOCK) 41, a first input/output port 42, and a second output port 48, and includes R, AM36, ROM38, CPTJ40.
CLOCK41. 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 by a bus 50. The first input/output port 42 includes a buffer (not shown), a multiplexer 54, and an analog-to-digital (A/1.)
') The air flow meter 2, the cooling water temperature sensor 24, the intake air temperature sensor 4, etc. are connected via the converter 56. The multiplexer 54 and A/D converter 56 are controlled by signals output from the first input/output port 42. The second input/output port 44 is connected to the 02 sensor 2 via a buffer (not shown) and a comparator 62.
2 is connected to the cylinder discrimination sensor 3o and the engine rotation angle sensor 32 via the waveform shaping circuit 64.The second input/output port 44 also has a bandpass filter 60, a peak hold circuit 61, and a channel switching circuit. circuit 6
A knocking sensor 18 is connected via an A/D converter 68 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, and a reset signal is input to the peak hold circuit 61 from the second input/output port 44. 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 θBASH expressed by the engine speed and the intake view, the basic fuel injection amount, etc. The basic ignition advance angle and the basic fuel injection amount are read by the signal from the angle sensor 32, and the basic ignition advance angle and the basic fuel injection amount are read 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 amount, and the igniter 28 and the fuel injection valve 12 are controlled. 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°C when the present invention is implemented using a microcomputer. first,
In step 811C, 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 transferred to the band bus. Fi/L/ Taro 0
, is input to the A/D converter 68 via the integrating circuit 63 and the channel switching circuit 66, and starts A/D conversion of the average value of engine vibration, that is, the background level.

Subsequently, in step 87, the knock gate is turned to the closing side t.
11, that is, calculate the next time to close the knock gate, and calculate the time - opening and closing time, and then in step 88 step 82
The crank angle is 90℃A based on the flag set by BTD
It is determined whether or not it has reached C (before top dead center). If the crank angle is not 90°C A BTDC, the process advances to step 91, and if it is 90°C A BTDC, the correction advance amount θ is updated to θ and the ignition timing is calculated (details of this are given below). In step 90, 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 B is set, and an igniter-on flag is set. Then, in step 91,
It is determined whether the crank angle has reached 60°C A BTDC or not, and if it is not 60°C A BTDC, return to the HOME routine L. If it is 60°C A BTDC, the igniter off time is calculated in step 92. Set time coincidence interrupt B and lower the igniter-on flag set in step 9o.

Next, the time coincidence interrupt A[' shown in FIG. 7 will be explained. This interrupt routine is to find the peak value of engine vibration, and when the time set in step 87 in FIG. A/T) is input to the converter 68 via the circuit 66 to start A/Di conversion of the peak hold value, and the process returns 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 90 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 or not. If the flag is set, the igniter is turned on in step 96, and if the flag is off, the igniter is Turn off and return to the main routine.

Figure 9 shows the A/D conversion completion interrupt routine, and shows the A/D conversion completion interrupt routine.
This interrupt occurs when the conversion and A/D conversion of the peak hold value is complete. 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.
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, 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 that is performed every predetermined time (for example, 4 m5 ec) for counting the time when no knocking occurs and the time for learning control. Instead, in step 102, the count value of the counter TIMEI, which calculates the time when knocking does not occur, is increased by 1, and in step 103, the counter 'I' I M E 2 calculates the time for learning control.
Increase the count value by 1. In the next step 104, the count value of the counter T I M E 1 becomes 12.
(48 msec) or less. If the count value exceeds 12, step 10
In step 5, the count value of the counter TIMEI is set to 12, and when the count value is 12 or less, it is determined in step 106 whether the count value of the counter TIME2 is 12 or less. Here, if the count value exceeds 12, the counter T
The count value of IME2 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 explained based on the eleventh column. When it is determined in step 88 of FIG. 6 that the crank angle has reached 90°A BTDC, the load Q, /N is determined to be 0.6 CL/ in step 122.
rev, ': Determine whether or not it is 1 or more, that is, whether it is a non-knocking control region or a knocking non-control region. Load is 0.
6 (L/rev, ), that is, in the knocking non-control region, the basic ignition advance angle θBASK is set as the ignition advance angle θif in step 123 and the process proceeds to the next routine.In the knocking non-control region, unlike the conventional method, Do not reduce the correction retard amount to zero.On the other hand, if the load is 0.6 (
t/rev, :) or more, that is, in the knocking control region, in step 108, the peak value a stored in step 100 of FIG. constant k
Compare the multiplied value with -b. Peak value a or value -
If it exceeds b, it is determined that knocking has occurred, and in step 110, the correction retard amount θK stored in the RAM is increased by a predetermined angle (for example, 0.4°C A), and in step 112, the time during which knocking does not occur is increased. Clear the count value of the counter TIMEI. On the other hand, when the peak value a is less than or equal to the value -b, it is determined that no metering occurs, 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 the value is greater than or equal to the predetermined value, it means that a state in which no knocking occurs has continued for a predetermined period of time.
The correction retard amount θK stored in
℃A), then in step 112 the counter T I
Clear M E 1. Further, if the count value is less than the predetermined value in step 109, the process proceeds to step 113. In step 113, the basic ignition advance angle is determined by using the corrected retard amount θ obtained as described above and the learning retard amount θKG obtained from the learning map by the two-dimensional interpolation method, as shown in the above-mentioned equation (1). Ignition advance angle θI2 that corrects θRASE and actually controls the igniter
Calculate.

As mentioned above, the corrected retardation amount θ calculated in the non-knocking control area is not cleared (4 is stored in the RAM, so even if the engine condition moves from the knocking control area to the knocking non-control area) The final corrected retardation amount calculated within the non-king control area is stored and held, and when the engine condition shifts to the knocking control area again, knocking is controlled using the stored corrected retardation amount.

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, the load Q/N is 0.6 [
L/rev. If it is not in the knocking control region, the main routine continues as it is, and if it is in the knocking control region, in step 114, the four points in the RAM surrounding the point indicating the current engine condition determined by the engine speed N and the load Q/N are stored. Find the street address on the learning map. Next, in step 115, the obtained four points R, A
The data stored at address M, that is, 4 points of RA
Using the two-dimensional interpolation method (the routine of the two-dimensional interpolation method will be explained later) based on the learning retardation amount stored at the address M,
The learning retardation amount θKG at the point indicating the current engine condition is calculated, and the calculated value is stored in a predetermined location in the RAM. At step 116, it is determined whether or not the count value of 4B2 is greater than or equal to a predetermined value (for example, 12), which is sent to the counter T for calculating the learning control time counted at step 103 in FIG. If the count value is less than the 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 'I' I M E2 is cleared in step 117, and then
The corrected retardation amount θK updated in steps 110 and 111 in FIG. 11 is the first predetermined crank angle (for example, 2°C
It is determined in step 118 whether or not this is the case.

If it is determined in step 118 that the corrected retardation amount 6K 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° C.A.) from each retard amount, and the main routine heliturf is performed. As a result, when the corrected retardation amount θK is less than the first predetermined crank angle, learning control is performed so that the learning retardation amount of the learning map becomes smaller1, and the ignition timing is controlled to advance according to the learning retardation 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 first predetermined crank angle. at a predetermined crank angle (e.g. 4°C)
A) Determine whether it is less than or not. 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 amount θK satisfies the following conditions, the first predetermined crank angle (2°C A)≦θK<second predetermined crank angle (4°C A) (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
At 0, learning control is performed to add a predetermined crank angle (for example, 0.04°C) to each of the learning retard amounts stored at four points on the learning map surrounding the point indicating the current engine condition. Routine heritor 7-f. 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 in step 115 of FIG. 12. In this two-dimensional interpolation routine, the map shown in Fig. 1 is used as a learning map, and the addresses of four points R and AM indicating the current engine conditions are set as 0% n+1, n +6, as shown in Fig. 2. n
+7. First, in step 30, the current load Q/N is the upper limit of the load on the learning map, that is, 1.2.
[t/rev,] Determine whether it is less than or equal to [t/rev,]. If the load exceeds 1.2 [near/rev,:], 1.2 is stored in register n in step 131, and if the load is less than 1.2 (1/rev,), step 131 is executed. At step 134, the current load Q/N value is stored in register n. At step 135, the current engine speed N is set to the upper limit of the engine speed on the learning map, that is, 6000.
[r, p, m] Determine whether it is the following. If the engine speed exceeds 6000 (r, p, m:), register m[6000 is stored in step 136, and the engine speed is 6000 Cr, p, rr+
), in step 137, the value of the current engine rotation speed N is stored in register m. Step 138
Now, it is determined whether the value of register n is greater than or equal to the lower limit of the load on the learning map, that is, 0.6 [:t/rev, :], and if the value of distal is less than 0.6, then In step 139, the value of register n is set to 06, and if the value of register n is 06 or more, the process proceeds to step 140. Then, in step 140, register m
It is determined whether the value of the register m is greater than or equal to the lower limit value of the engine rotation speed on the learning map, that is, 1000 (r, p, m3), and if the value of the register m is less than 1000, the value of the register m is set to 1000 in step 141. When the value of 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, the values are stored in registers m and 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 n, 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 0.6 (j/rev, ) at address 0 from the value of register n is stored in register n. Next, in step 143, the value of register n is stored in the load scale interval 0, 21
:t/rev, ), 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 arrangement of addresses, for example 0
5 is the first column).

Then, in step 144, the value of register y is further divided by 0.2 (L/rev, ).

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

In step 145, similarly to the above, the value of the engine rotation speed at address 0 is changed from the value of register m to 1000 [r-p-m
] The value obtained by subtracting is stored in register m. Next, in step 146, the value of the register m is set to 1000 [r], which is the scale interval of the engine rotation speed.

p0m], 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 stored in 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.
16, 12, and 188 are listed in the first row). Then, in step 147, the value of register X is further divided by 1000 (r, p, m). Therefore, in the end, register
A value corresponding to x/X in equation (5) is stored.

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
KG(n+1) is read and stored in register B, and n+
Learning delay angle θKG stored in address 6 (n+6)
is read out and stored in register C, and the learning retard amount θKG(n+7) stored at address n+7 is read out and stored in register D. Next, step 151
Then, 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 this value, and the result is stored in register E. Also, step 1
52, the value of register D is subtracted from the value of register C, multiplied by the value of register
The values of are added and 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 of steps 118 to 121 in FIG. 12 is shown in FIG. 14. The register n in FIG. 14 uses the register n of the two-dimensional interpolation routine in FIG. First, in step 118, similarly to the above, it is determined whether the corrected retard amount θK is equal to or greater than 2°C. When the corrected retardation amount θK is less than 2°C, the learned value α is set to 1004°C in step 160, and the process proceeds to step 162. When the corrected retard amount θK is 2° C.8 or more, it is determined in step 119 whether the corrected retard amount θK is 4° C.8 or more. If the corrected retardation amount θK is less than 4°C, the process returns to the main routine, and if the corrected retardation amount θK is 4°C or more, the learned value α is set to 0.04°C in step 161, and the process proceeds to step 162. move on. In step 162, it is determined whether the load Q, /N is greater than or equal to the lower limit value of 0.6 (7/rev,) of the learning map. If the load is 06 or more, step 16
6, the engine speed N is the lower limit of the learning map 10
00 (r, p1m+) or more, and if the load is less than 0.6, in step 163 it is determined whether the engine rotation speed N is 1000 [r, p, m+] or less. to decide.

In step 166, the engine speed N is 1000.
[: r, p, m) If it is determined that the value is less than [: r, p, m), learning control is performed in which the learned value α is added to the previously learned learned retard amount θKGn at address n in step 167, and in step 168 Learning control is performed in which the learned value α is added to the previously learned learned retard amount θKG (n+1) at the address, and the process returns to the main routine. As mentioned above, the current engine speed N and load Q, / N vs Q, / N≧
0.6 (t/rev, :)gN〈1000 (r
, p, m), the value of register n indicating the RAM address will be 0.6.12.18 in the first row, so the point indicating the current engine condition will be exists in the area of 0.6.12. in step 167.
The learning delay amount at address 18 is controlled by learning, and step 168
The learning retardation amount at address 13.19 is controlled by learning by 1.7%.

In step 166, the engine speed N is 1000.
(r, p, m:) When it is determined that the above is the case, learning control is performed in step 169 in which the learning value α is added to the previously learned learning retard amount θKG at address n. The point indicating the current engine condition is Q/N≧0.
6 (t/rev, ) and N≧1000Cr-p, m
), the value of register n indicating the RAM address can take a value from 0 to 23, so step 169
In this case, all addresses are subject to learning control. In the next step 170, it is determined whether the value of register n is not 3 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, and 5, respectively. The value 5.11.17.23 of this register n represents the address of the sixth row. When the value of register n 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. When the value of register n is 17.11.5, the value of register n is decreased by 1 in step 172, and the learning retard amount θKG (n+
Learning control is performed to add the learning value α to 7), and the process returns to the main routine. Therefore, the value of register n is 1
7, when it is 11.5.

In step 169, the learning retard amounts at addresses 17, 11, and 5 are each subjected to learning control, and in step 178, the learning retard amounts at addresses 17, 11, and
The learning retard amounts of addresses 3, 17, and 11 are each subjected to learning control.

When the value of register n is neither 23.17.11.5, learning control is performed in step 175 in which the learning value α is added to the learning retard amount θKG(n+4) at address n+1. However, if the RAM address obtained in step 149 of the two-dimensional interpolation routine is 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 176,
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 address of R'AM is 1 in the fourth column.
When the number is 8 to 22, learning control is performed on the address stored in register n and the address to the right of it in steps 169 and 175. On the other hand, if the value of register n is less than 17, that is, if there are four addresses surrounding the point indicating the current engine condition, then step 17
In step 7, learning control is performed to add the learning value α to the learning retard amount θKc(n+6') at address n+6, and in step 17
At step 8, learning control is performed to add the learning value α to the learning retard amount θKG (n+7) at address n+7. 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 controlled in steps 169, 175, 177 and 178.

At step 162, the load is 0.6 [t/rev, :]
If it is determined that the engine rotation speed is less than 1000 [r, p, m), it is determined in step 163 whether the engine rotation speed is less than 1000 [r, p, m).

If the engine speed is less than 1000 (r, p, m), subtract 7 from the value of register n in step 165,
Learning control is performed in step 178. The point indicating the current engine condition is Q, /N<0.6 Ct/rev,) and N
≦1000 [r, p-m''J (r) When the value exists in the region, the value of register n becomes O, so in step 178 in this case, the learning delay amount at address 0 is controlled by learning. .On the other hand, when the engine speed N is 1000
If it exceeds (r, p, m'), step 1
In step 64, it is determined whether the value of register n is 5 or not, and if it is not 5, 5.6 is subtracted from the value of register n in step 179, and step 177 and step 1 are performed.
At 78, learning control is performed on the learning retardation amounts at addresses n-4-6 and n-4-7.

When the value of register n is 5, 7 is subtracted from the value of register nO in step 180, and learning control is performed in step 178. The point indicating the current engine condition is Q, /
N< 0.6 (L/rev, ) and N> 100
0 [r, pom) (7) Exist in area t 7)
In Toki, the value of register n can take the value of the address in the first column, so when the value of register n is 5, the learning delay amount at address 5 is controlled by learning in step 178, and the value of register n is In step 177 and step 178 of 0, 1, 2.3.4, 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
Corrected retarded bone θ when updating G by learning control
7) The relationship between the conditions and the increase/decrease in the learning retardation amount θKG is summarized in the following table.

Further, FIG. 15 shows the changes in the corrected retard amount θ, learned retard amount θKG, and ignition timing θ12 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 θ
When K exceeds a predetermined range, the learned retard amount θKG increases, and when the corrected retard amount θK falls below the predetermined range, it decreases.

Furthermore, FIG. 16 shows variations in ignition timing corresponding to engine speed. In Fig. 16, curves 01 to C3 are the same as those in Fig. 3, and it is understood that the corrected retardation amount θK always remains constant, whether knocking is likely to occur or knocking is unlikely to occur. be done.

Further, FIG. 17 shows the characteristics of ignition timing with respect to load. In the figure, the solid line indicates the basic ignition advance angle, the curve C4 indicates the ignition timing at which slight knocking occurs, and the curve C3 indicates the ignition timing retarded by the learning retard amount. In the above embodiment, since the correction retardation amount is stored and held when the engine condition shifts from the knocking control region to the knocking non-control region, the load changes from light load A to load B in the non-knocking control region. Also, since the ignition timing is controlled along curve C4, no knocking occurs. However, if the corrected retardation amount is O'cA as in the past, when the load changes as described above, the ignition timing will change to curve C in the initial state.
Since the control is performed along the curve C3, which is more advanced than the curve C3, knocking will occur.

[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 flow chart of the interrupt routine every 30°C, Fig. 7 is a flow chart of the time match interrupt, and Fig. 8 is a flow chart of the time match interrupt B. , Figure 9 Al1) Flowchart of Completion Interrupt Routine,
Fig. 10 is a flowchart showing the interrupt routine every 4 m5ec, Fig. 11 is a flowchart of the routine for updating the correction retardation amount, Fig. 12 is a flowchart of the learning control routine, and Fig. 13 is a flowchart of the routine for updating the correction retardation amount.
A flowchart of the dimensional interpolation routine, FIG. 14 is a flowchart showing details of the learning routine, and FIG. 15 is a diagram showing changes in the correction retardation amount, learning 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 FIG. 3, and FIG. 17 explains the ignition timing of the embodiment of the present invention. FIG. 2 is a diagram showing the relationship between load and ignition timing for the purpose of the present invention. 2...Air flow meter, 12...Fuel injection valve, 18...Knocking sensor, 32'...Engine l [1 Turn angle sensor, 34...Electronic control circuit. Agent Tatsuyuki Unuma (L (v゛2ro) Fig. 1 Fig. 2) Fig. 3 (2) Esojishi Kaikan @ Fig. 6 Fig. 7 @ Fig. 8 Fig. 9 Fig. 11 Fig. 12 Fig. 15 'M &”+ M a −/,,. Fig. 16 Enshishiro medium type Kin

Claims (2)

[Claims] (1) Within the knocking control range of a predetermined load or higher, the basic ignition advance angle is determined by the engine speed and load and changed by learning control to maintain the knocking level to a predetermined level from the basic ignition advance angle determined by the engine speed and load. A knocking control method for an internal combustion engine in which knocking is controlled by subtracting the sum of a learned retardation amount to be retarded and a corrected retardation 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, characterized in that when engine conditions shift from the knocking control region to the knocking non-control region, the corrected retardation amount at the time of transition is stored and retained. (2) The knocking control method for an internal combustion engine according to claim 1, wherein the learning retardation amount is set so that the corrected retardation amount remains within a predetermined range within the knocking control region.