JPS59138774A - Control method for knocking of internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent generation of knocking when the load changes, by giving a specific value exceeding zero to the correction amount of angle delay in the knocking uncontrolled range under a specific load. CONSTITUTION:In the attached illustration, solid line represents the fundamental angle advance for ignition while curves C4 and C5 are the ignition timing with micro-knocking generation and the ignition timing delayed by the study angle delay amount, respectively. Because a CA specific value, for ex. 3 deg., is given to the correction amount of angle delay in the knocking uncontrolled range, the ignition timing is controlled as along the curve C4 even though the drawn cargo has changed from light load A to a load B in the knocking control range. Thus no knocking will be produced.

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.

In the conventional knocking control method using learning control, the ratio of the engine rotation speed N1 to the intake air amount Q and the engine rotation speed N is Q/
The basic ignition advance angle θBASE is predetermined by the load determined by N or the negative pressure in the intake pipe. The ignition advance angle θiyk for all igniter control is calculated, and this ignition advance angle is used to perform all knocking control. Further, in a light load range 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.

θiy=θBASE (θKG+θK)・・・・・・
・・・・・・・・・ (1) However, θKG is the learning retardation amount determined by the engine speed and load and changed by learning control in order to bring the knocking level to a predetermined level, and θ is the amount of learning retardation that is changed by learning control. This is a correction retard amount that retards the ignition timing when knocking occurs and advances the ignition timing when knocking no longer occurs.

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

First, engine vibration is detected using a knocking sensor composed of a microphone, etc., and the average value (background) of engine vibration is multiplied by A (where K is a proportionality constant) and the peak of engine vibration. Determine the value a(!:'fc) and compare this peak value with the value of K・b. If the peak value α exceeds the value of b, it is determined that knocking has occurred and the following formula (2) is used. As shown in the figure, the corrected retardation amount θK is changed so that the ignition timing is delayed by a predetermined crank angle (for example, 0.4° CA) for each non-king occurrence.

To θ←θx + 0.4°CA ・・・・・・・・・
・・・・・・・・・・・・ (2) When the peak value α is less than the value α−b, it is determined that knocking has not occurred, and the first timer is used to control the timing for a predetermined period of time (e.g. 4
8m5ec) has elapsed, and when the predetermined time has elapsed, the corrected retardation amount θKk is changed so that the ignition timing advances by a predetermined crank angle (for example, 0.08° CA) as shown in the following equation (3). .

θK ← θxo, 08° CA...In between...
(3) Also, the learning retardation amount θK according to engine conditions
G is calculated as follows. First, as shown in Fig. 1, addresses 0 to 23 for storing all 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. The engine speed N and intake air amount Q are taken in, and the RAM addresses of four points surrounding the point (N, Q/N)' indicating the current engine condition on the learning map are determined.

Now, as shown in Figure 2, the RAM address surrounding the point indicating the current engine frost is yb (+z = Q, l, ・16)
, ru+1, ru+6, ru+7, the learning retardation amount θKG is at address ru, and the learning retardation amount θxc(yL+1) is at address ru+1.
, a learning retard amount θKG (rL+6) is stored at address 'R+6, and a learning retard amount θxc (n, +7) is stored at address R+7. Then, the difference in engine speed between addresses is fcX, and the difference in load between addresses is Y1, and the difference in engine speed between address 1 and a point indicating the current engine condition is x1, which indicates the current engine condition. The difference in load between the points f
:y, the learning retardation amount θKG of the point indicating the current engine position is determined by the two-dimensional interpolation method shown in equations (4) to (6) below.

The learning control of the learning map is performed as follows. First, a second timer that determines the learning control time depending on the current engine condition and a third timer that determines the learning control time regardless of the engine strip are prepared. A second timer is used for a predetermined period of time (for example, 48m5ec).
), when it is detected that the correction retard amount θK
is changed and exceeds a predetermined crank angle (for example, 4° CA)'i, and when the corrected retard amount θK exceeds the predetermined crank angle, the point indicating the current engine condition explained above is determined. A predetermined crank angle (for example, 0.04° CA) is added to the learning retardation amount of the four points on the surrounding learning map.

As a result, the learning retard amount is learning-controlled so that the ignition timing is delayed. On the other hand, the third timer is set for a predetermined time (for example, 1
6) When it is detected that the ignition timing has elapsed, the ignition timing is advanced by subtracting a predetermined crank angle (for example, λ is 0.018CA) from the learning retard 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 retard amount θ changed as described above and the learned retard amount θKG obtained by the two-dimensional interpolation method from the learning map subjected to learning control, the calculation is performed based on the equation (1) above. Then, the basic ignition advance angle θBASIE 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 in this knocking non-controlling area, the amount of correction retardation is completely zero and knocking Since no control is performed, when the engine conditions change from the non-knocking control region to the knocking control region, since the supplementary retardation amount is small, learning control is performed to reduce the learning retardation amount, and the knocking is prevented. There was a problem in that this caused a negative impact on the engine, and the learning retardation amount learned last time on the light load side was changed.

The present invention has been made in order to solve all of the above problems, and provides a method for controlling knocking in an internal combustion engine in which when engine conditions change from a knocking non-control region to a knocking control region, the optimum ignition timing is quickly reached and knocking does not occur. The purpose is to provide.

In order to achieve the above object, the configuration of the present invention is to increase the engine rotational speed to bring the level of knocking to a predetermined level from the basic ignition advance angle determined by the engine rotational speed and the load within the knocking control region of a predetermined load or more. Subtract the sum of the learned retard amount, which is determined by the and load, and is changed by learning control, and the corrected retard amount, which retards the ignition timing when non-king occurs and advances the ignition timing when knocking no longer occurs. In the knocking control method for an internal combustion engine, the knocking control method for an internal combustion engine is performed, and the knocking retardation amount is set to zero within the knocking non-control region where the load is less than the predetermined load. It is possible to set the value to a predetermined value exceeding zero. here,
It is preferable that the predetermined value of the supplementary retard amount is selected from a value within a predetermined range of the corrected retard amount in the knocking control region.

According to the above configuration of the present invention, since the corrected retard amount is set to a predetermined value exceeding zero in the knock non-control area, when the engine condition changes from the knock non-control area to the knock control area, the corrected retard amount is set to a predetermined value exceeding zero. This provides the unique effect that the optimal ignition timing is quickly reached, no knocking occurs, and therefore no abnormal learning control is performed.

In addition, as shown in FIG. 3, the basic ignition advance angle θBASE, that is, M B 'p
Advance for Best 'Porge)
changes like curve C3 depending on the engine speed,
The ignition timing at which slight knocking occurs when knocking is difficult to occur, such as when the air is humid, is as shown by curve C2, and the ignition timing at which slight knocking occurs when knocking is likely to occur, such as when the air is dry, is as shown in curve C2. As shown by curve c3, the ignition timing at which slight knocking occurs varies depending on the p1 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 knocking is likely to occur and operating conditions where knocking is unlikely to occur, the supplementary retardation amount is set to a predetermined value in the learning control within the knocking control region. range (e.g. 2° CA
It is preferable to change the learning retardation amount so that it becomes a value of ≦θ and ≦4° CA).

Next, FIG. 4 shows an example of an engine to which the present invention is applied. This engine has an air cleaner (
An air flow meter 2 is provided as an intake air amount sensor provided on the downstream side of the engine (not shown). The air 70-make 2 includes a compensation plate 2A rotatably provided in the damping chamber and a potentiometer 2B that detects the opening degree of the convention plate 12A.
It is composed of. Therefore, the intake air 1ltQ is detected as a voltage output from the potentiometer 2B. Further, an intake air temperature sensor 4 is provided near the air flow meter 2 to detect the temperature of intake air.

A throttle valve 6 is disposed downstream of the air flow meter 2, and a surge tank 8 is disposed downstream of the throttle valve 6.
is provided. An intake manifold 10 is connected to the surge tank 8, and a fuel injection valve 12 is disposed protruding into the intake manifold lo. The intake manifold 1o is connected to the combustion chamber 14A of the engine body 14, and is connected to the combustion chamber 14A of the engine body 14.
4A is connected via an exhaust manifold 16 to a catalytic converter (not shown) fully filled with a three-way catalyst. A knocking sensor 18 is provided, which includes an engine body 14Kid, a microphone, etc., and detects all images of the engine.

Note that 20 is a spark plug, 22 is an O2 sensor for controlling the air-fuel mixture near the stoichiometric air-fuel ratio, and 24 is a cooling water temperature sensor for detecting the engine cooling water temperature.

The spark plug 2o of the engine body 140 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, for example, every 720 degrees of crank angle to an electronic control circuit 34 made up of a microcomputer, etc., 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 electronic control port j834.

The electronic control circuit 34, as shown in FIG.
Access Φ memory (RAM) 36, read only memory (ROM) 38, and central processing unit (CPU)
) 40, a CLOCK 41, a first input/output port 42, a second input/output port 44, a first output port 46, and a second output port 48. RAM36, ROM38, CPU40. C.L.O.
The CK 41, the first input/output port 42, the second input/output port 44, the first output port 46, and the second output port 48 are connected to the bus 5o. First input/output port 42K, buffer (not shown), multiplexer 54, analog-digital (A/D) converter 5
6, air flow meter 2, cooling water temperature sensor 24
and an intake air temperature sensor 4, etc. are connected. The multiplexer 54 and A/D converter 56 are controlled by signals output from the first input/output port 42. Second
The input/output port 44 of 0.0. The sensor 22 is connected,
A cylinder discrimination sensor 3o and an engine rotation angle sensor 32 are connected via a waveform shaping circuit 64.

In addition, my second input/output boat 44 includes a bandpass filter 60, a peak hold circuit 61. Knocking sensor 18 is connected via channel switching circuit 66 and 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 is connected to the fuel injection device 12 via a second output port 481d 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 intake air amount, the basic fuel injection amount, etc. The basic ignition advance angle and the basic fuel injection amount are read out based on the signal from the angle sensor 32, and the basic ignition advance angle and the basic fuel injection amount are read out based on various signals including signals from the cooling water temperature sensor 24 and the intake air temperature sensor 4. The corrected ignition advance angle and corrected fuel injection amount are added to the basic fuel injection amount, and the igniter 28 and the fuel injection valve 12 are controlled. 0. The air-fuel ratio signal output from the sensor 22 is used for air-fuel ratio control to control the air-fuel ratio of the air-fuel mixture to near the stoichiometric air-fuel ratio. Further, the learning map shown in FIG. 1 is stored in advance in the RAM 36 of the electronic control circuit 340.

Next, an embodiment in which the present invention is applied to the engine as described above will be described in detail. In addition, in explaining the present invention in detail, the main routines of fuel injection control, air-fuel ratio control, ignition timing control, etc. are the same as conventional ones, so the explanation will be omitted, and only the knocking control routine related to the present invention will be explained. explain.

FIG. 6 shows an interrupt routine every 30° CA when the present invention is implemented using a microcomputer. First, in step 81, the engine rotation speed Nt is determined 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, the flag set in step 82 is at top dead center (T
DC) 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 odor lock gate is closed. When the knock gate is open, the knock gate is fully 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 f18 is switched to a pantone filter. 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.
1%, that is, the next time to close the knock gate e, and set all time coincidence interrupts A.

Next, in step 88, it is determined based on the flag set in step 82 whether the crank angle has reached 90° CA BTDC (before top dead center). Crank angle is 90°C
A If it is not BTDC, proceed to step 91, 9
When it is 0° CA BTDC, the corrected advance angle amount θ is updated in step 89, and the entire ignition timing calculation process is performed (details of this will be explained below). In step 90, the time to turn on the p 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 7 lags for the igniter to be turned on are set. Then, in step 91, it is determined whether the crank angle has reached 60° CA BTDC, and if it is not 60° CA BTDC, the process returns to the main routine, and if it is 60° CA BTDC, the igniter is turned off in step 92. The time is calculated and set in the time coincidence interrupt B', and the igniter-on flag set in step 90 is lowered.

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

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

FIG. 8 shows the routine of time coincidence interrupt B. When the time set in step 90 and step 92 of FIG. 6 arrives, an interrupt 75 is performed. Step 9
In step 4, it is determined whether the igniter on flag is set, that is, whether this flag is 1 crab or not, and if the flag is set, the igniter is turned on in step 96. Turn off the igniter and return to the main routine.

FIG. 9 shows the A/D conversion completion interrupt routine. This interrupt is performed when the A/D conversion of the bank ground level and the A/D conversion power of the peak hold value are completed. First, in step 97, it is determined whether or not the knock gate is currently open.If the knock gate is closed, the process proceeds to step 98, as shown in FIG.

The A/D conversion value converted in step 86 is stored in the memory of the RAM 36 and set as background level b, and in step 99 the knock gate is opened and the process returns to the main routine. On the other hand, when the knock gate is open, the seventh
A/D conversion value eRAM36 converted in step 93 in the figure
The knock gate is stored in the memory as the peak value α, and in step 101 the knock gate is closed and the process returns to the main routine.

FIG. 10 shows an interrupt routine that is performed every predetermined time (for example, 4 m5ec) for counting the time when no knocking occurs and the time for learning control. First, in step 102, a counter TIM is used to calculate the time when knocking does not occur.
The count value of E1 is incremented by 1, and in step 103, the count value of counter TIMP22 for determining the learning control time is incremented by 1. In the next step 104, the count value of the counter TIMEI becomes 12 (48rrL).
SeC) and below. If the count value exceeds 12, the count value of the counter TIMEI is set to 1'2 in step 105, and if the count value is 12 or less, it is determined in step 106 whether the count value of the counter TIME2 is 12 or less. . Here, if the count value exceeds 12, in step 107 the counter TIME2 is
The count value is set to 12 and the process returns to the main routine, and when the count value is 12 or less, the process returns to the main routine.

Next, the detailed routine of step 89 in FIG. 6 will be explained based on FIG. 11. When it is determined in step 88 of FIG. 6 that the crank angle has reached 90° CA BTDC, in step 122 the load Q/N becomes Q, 5 [t/r
gv, ] or more, that is, whether it is a knocking control region or a non-knocking non-control region. Load is 0.6C
L /7J, : ], that is, in the knocking non-control region, the correction retard amount θK stored in the RAM is set to a predetermined value (for example, 3° CA) in step 123.
At the same time, in step 124, the basic ignition advance angle θ
BAsE is set as the ignition advance angle θiy and the process proceeds to the next routine.

The value 3°CA of the correction retardation amount exemplified above is within a predetermined range of the correction retardation amount (for example, 2°CA≦θ and ≦4°
CA). On the other hand, the load is 0.6 (L/r
ev, ), that is, in the knocking control region, in step 108, step 100 in FIG.
The peak value α stored in step 98 is compared with h, which is the value obtained by multiplying the background level b stored in step 98 of FIG. 9 by a constant K. When the peak value α exceeds the value −hf, it is determined that knocking has occurred, and in step 110, the correction retard amount θxe is set at a predetermined angle (for example, 0.
4° CA) and counts the time during which knocking does not occur in step 112.
Clear the count value. On the other hand, the peak value α becomes the value,
If it is less than h, it is determined that knocking will not occur, and in step 109 it is determined whether the count value of the counter T I ME 1 is greater than or equal to a predetermined value (12). Since the state in which knocking does not occur continues for a predetermined period of time, the corrected retard amount θxk is decreased by a predetermined angle (for example, 0.08° CA) in step 111, and then the counter TIMF:1 is cleared in step 112. Also, step 1
If the count value is less than the predetermined value in step 09, the process advances to step 113. In step 113, the basic ignition advance angle is calculated by using the corrected retard amount θ obtained as described above and the learning retard amount θKG obtained from the learning map by two-dimensional interpolation, as shown in the above-mentioned equation (1). θaAsg
Ignition advance angle θiy that corrects and actually controls the igniter
Calculate f.

Next, a routine for determining the learning retardation amount θKGk 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 126, the load Q/N is 0.6 [t
/γgv, ) or more, that is, whether or not it is in the knocking control region. When not in the knocking control area,
The main routine continues as it is, and if it is in the knocking control region, the engine speed N is changed in step 114.
The RAM addresses of four points surrounding the point indicating the current engine condition determined by Next, in step 115, a two-dimensional interpolation method (two-dimensional interpolation method (The routine will be explained later), the learning retardation amount θKG of the point indicating the current engine condition is completely calculated and the calculated value is stored in a predetermined location of tRAM. In step 116, it is determined whether the count value of counter TIME2 for determining the learning control time counted in step 103 of FIG. 10 is equal to or greater than 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 TIME2 is cleared in step 117, and then updated in steps 110 and 111 in FIG. The corrected retard amount θK is set to the first predetermined crank angle (for example, 2°
CA) It is determined in all steps 118 whether or not the result is greater than or equal to CA).

If it is determined in step 118 that the corrected retardation amount θK is less than the first predetermined crank angle, r is stored in four points on the learning map surrounding the point indicating the current valley engine condition in step 121. 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 learning retard amount of the learning map becomes smaller, and the ignition timing is controlled to advance by the learned retard amount. On the other hand, if it is determined in step 118 that the corrected retard amount θK is equal to or greater than the first predetermined crank angle, then in step 119 the corrected retard amount θK is set to a value larger than the first predetermined crank angle. 2 predetermined crank angles (e.g. 4
°CA). Step 119
If it is determined 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° CA) ≦θ Second predetermined crank angle (4° CA) (7) Return to the main routine without learning control.

As a result, when the corrected retard amount θK takes a value within a predetermined range, learning control is not performed, and the ignition timing is not changed depending on the learned retard amount. Note that even when the corrected retard amount takes a value within a predetermined range, learning control may be performed as necessary. If it is determined in step 119 that the corrected retard amount θK is greater than or equal to the second predetermined crank angle, step 12
At 0, learning control is performed to add a predetermined crank angle (for example, 0104° 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 process returns to the main routine. do.

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 amount of school retardation in the learning map is increased, and the ignition timing is controlled to be delayed by the amount of retardation.

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 gold shown in Figure 1 is used as a learning map, and the four RAM addresses representing the current engine conditions are set as shown in Figure 2. +7. First, in step 130, the current load Q/
N is the upper limit of the load on the learning map, that is, 1.2 [t
/re, v,) or less. If the load exceeds 1.2 [t/ygv,) f, 12 is stored in the register in step 131, and the load is reduced to 1.2.
(L/rgv,) or less, the current value of load Q/H is stored in register 1 in step 134. In step 135, the current 1797 engine speed N is the upper limit of the engine speed on the learning map, that is, 6000Cr,p,
m) or less. Engine speed is 6
If the engine speed exceeds 000 Cr,p,m'3'c, 6000' is stored in the register m in step 136, and if the engine speed is less than 6000 Cr,p,m:], the current value is stored in step 137. The value of engine rotation speed N is stored in register m. In step 138, the value of the register is set to the lower limit of the load on the learning map, that is, 0.6.
[L/rgv, make a full judgment as to whether or not it is greater than or equal to E. If the register value is less than 0.6, the register value is set to 0.6 in step 139, and if the register value is 0.6 or more, the register value is set to 0.6. Proceed to step 140. Then, in step 140, the value of register m is set to the lower limit of engine speed on the learning map, that is, 1000[:γ,P
Irn], and if the value of register m is less than 1ooo, the value of the register door is set to 1iooo in step 141, and the value of the register is set to 100.
If it is 0 or more, the process advances 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 le, respectively, and the current engine speed N and load Q/N are on the learning map. When the upper and lower limit values are exceeded, the upper and lower limit values are stored in registers m and l, 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 0.6 (t/'rev,:]k of the load at address θ from the value of the register is stored in the register.Next, in step 143
, the register value is set to 0, which is the load scale interval p,
2 (t/rev, ), store the integer part of the quotient in the register, and store the remainder of the quotient in the bt register y.
to be memorized. The value of this register y is equal to the load value y from address 1 in FIG. 2 to the point representing the current engine condition. In addition, the integer part of the quotient stored in the register is the row of addresses closest to the point indicating the current engine condition and below the point indicating the current engine condition (horizontal arrangement of addresses,
For example, the first column is a sequence of addresses 0 to 5). Then, in step 144, the value of register y is further divided by 0.2 CL /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 O is 1000C'', P, m from the register-only value.
The value obtained by subtracting 3'fr is stored in register m. next,
At step 146, the value in register m is ioo, which is the scale interval of the total engine speed.

Divide by Cr, p, mE and store the integer part of the quotient in register m
and store the remainder of the quotient in register X. The value of this register X is equal to the engine speed value X from address 1 in FIG. 2 to the point indicating the current engine condition. Further, 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... 12.18 is the first row). Then, in step 147, the value of register X is further increased to 1000 (T, P, yyt)"c'
Do the division. Therefore, the value corresponding to Z/X in the above-mentioned equations (4) and (5) is finally stored in register X.

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

In step 150, -Gn is read out from the learned retard amount θ stored at address 1 on the learning mass and stored in register A, and the learned retard amount θxc(rL+1) stored at address 1+1 is read out. is read out and stored in register B, and the learning retard amount θKG (7
1, +6) k is read out and stored in register C, and the learning retard amount θKG (rL+
7) Read '5r and store it in register D.

Subsequently, in step 151, the entire 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 value is stored in register E. Also, in step 152, the value of register D is subtracted from the value of register C, and the value of register X is multiplied,
Furthermore, 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, the value of register y is multiplied by the entire value, 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. Note that the register rL of the two-dimensional interpolation routine of FIG. 13 is used as the register path in FIG. First, in step 118, 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 αe−0.04°CA is set in step 160.
The process then proceeds to step 162. Correction retard amount θK is 2°C
If it is equal to or greater than A, it is determined in step 119 whether the corrected retard amount θK is equal to or greater than 4° CA. If the corrected retard amount θK is less than 4° CA, 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, the load Q/N
It is determined whether or not is greater than or equal to the lower limit value of the learning map 0.6 CLlr g v,). If the load is 0.6 or more, it is determined in step 166 whether the engine rotation speed N is more than the lower limit value 1000 [r, p, rrb] of the learning map, and if the load is less than 0.6. If the engine speed N is 1000 in step 163,
[τ, p, m': Determine whether it is less than or equal to l.

In step 166, the engine speed N is 1000.
Cr, p, ml), in step 167 learning control is performed in which the learned value α is added to the previously learned learned angle movement amount θ Learning control is performed in which the learned value α is added to the previously learned learned retard amount θKG1) at the address, and the process returns to the main routine. Here, as mentioned above, if the current engine speed N and load Q/N are in the region of Q/N ≧ 0.6 (t /rtv, ) and N < 100 ocy; P, m), The value of the register path indicating the RAM address can be 0.6.12.18 in the first row, so if the point indicating the current engine condition exists in the above area, step 1
At step 67, the learning retardation amount at address 016.12.18 is learning controlled, and at step 168, the learning retardation amount at address 1.7.13.19 is learning controlled.

In step 166, the engine speed N is 1000 [
r, P1m] or more, step 16
9, the previously learned learning delay angle θ at address 9
Learning control is performed in which a learning value α is added to KG. The point indicating the current engine condition is Q/N≧0.6 (L/
raV,] and N≧1000 [r, p, rn], the value of the register path indicating the RAM address can take θ~23, so all addresses are learned in step 169. be subject to control. Next step 1
At 70, it is determined whether the value in the register path is not 23 or not. If the value in the register path is not 23, step 17
1. In step 173 and step 174, respectively, whether the value of the register path is not 17 or not, 5
Determine whether or not. The value of this register path is 5.11
．． 17.23 represents the address of the 6th line. When the value of the register path is 23, the process directly returns to the main routine. The learning retard angle □ amount at address 23 at this time is controlled by learning in step 169. It turns out. If the register path value is 17.11.5, step 17
2, the value of the register path is decreased by 1 and step 17
At 8, the learning retardation amount θxc (rL+7) at address r+7
The learning value α is added to the learning flil control amount, and the process returns to the main routine. Therefore, when the value of the register path is 17.11.5, the learning delay amount of address 17.11.5 is controlled by learning in step 169.
In step 178, the learning delay amounts of the 23, 17, and 11% areas one row above are each subjected to learning control.

When the value of the register path is neither 23.17.11.5d, in step 175, learning control is performed in which the learning value α is added to the learning retard amount θxG (ru+1). That is, If the RAM address found in step 149 of the two-dimensional interpolation routine is not on the sixth row, the RAM address found in the two-dimensional interpolation routine and the address to the right of this address are learned in steps 169 and 175. In step 176, it is fully determined whether the register value is less than 17, and if the register value is 17 or more, the process returns to the main routine.In other words, the RAM address is in the fourth column. 18~
22, step 169 and step 17
In step 5, the address stored in the register and the address to the right of the address are subjected to learning control. On the other hand, the register value is 17
If the value is less than 1, that is, if there are four addresses surrounding the point indicating the current engine condition, then in step 177 learning control is performed to add the learning value α to the learning retard amount θKG (7L+6) at address LE+6. Then, in step 178, learning control is performed in which the learning value α is added to the learning retard amount θKc (rL-1-7) of LE+7 points. As a result, if there are four addresses surrounding the point indicating the current engine condition, step 169, step 175, step 1
In step 77 and step 178, the learning delay angle amounts of the four addresses are determined by learning control.

In step 162, the load is 0.6 [A,/rgv,'J
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 or equal to 1000 [r, p, m:].
In the following cases, 7 is subtracted from the value of the register in step 165, and learning control is performed in step 178. The point indicating the current engine condition is Q / N (0,6Ct /r
ev, :] and N≦1000 Cr, p, m], the value of the register is 0, so in step 178 in this case, the learning delay amount at address 0 is controlled by learning. Become. On the other hand, if the engine speed N exceeds i o o o cr, p, rn]+, it is determined in step 164 whether the value of register n is 5, and if it is not 5, in step 179 6 is subtracted from the value of the register, and in step 177 and step 178, the learning retard amount at addresses RU+6 and RU+7 is fully learned and controlled.

When the register value is 5, 7 is subtracted from the register value in step 180, and learning control is performed in step 178. The point indicating the current engine condition is Q/
N < 0.6 (L/r e v,] and N>1
000 [r, p0m] Since the value of the register can take the value of the address in the first column, when the value of the register is 5, the learning delay amount at address 5 is controlled by learning in step 178. , the resinutal value is 0.1.2.
3.4, in steps 177 and 178, the learning delay amount of the address of the register value and the address of its right neighbor 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 amount θ when G is updated by learning control and the increase/decrease in the learned retard amount θKG.

Further, FIG. 15 shows the variation of the corrected retard amount θ and the learning retard amount θKG% of the ignition timing θ 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 remains constant, and when the corrected retard amount θK exceeds the predetermined range, the learned retard amount θKG increases. However, when the corrected retard amount θK is less than a predetermined range, it decreases.

Further, FIG. 16 shows all the variations in ignition timing corresponding to engine speed. In FIG. 16, the curves CI to Cs 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. .

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 C5 indicates the ignition timing retarded by the learning retard amount. In the above embodiment, since the corrected retardation amount θK is set to a predetermined value of, for example, 3° OA within the knock non-control region, even if the load changes from light load A to load B within the knock control region, the ignition Since the timing is controlled along curve C4, knocking does not occur. However, if the corrected retard amount is set to 0°CA as in the past, when the load changes as described above, the ignition timing will be controlled along the curve C6, which is more advanced than the curve C2, in the initial state. As a result, knocking will occur.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the learning map, Fig. 2 is an explanatory diagram showing a point indicating the current engine condition and the four points surrounding this point, and Fig. 3 is a diagram showing 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. FIG. 8 is a flow chart of time match interrupt A, FIG. 9 is a flow chart of time match interrupt B, and FIG. 9 is a flow chart of A/D completion interrupt routine.
Fig. 1θ is a flowchart showing an interrupt routine every 4m5ec, Fig. 11 is a flowchart of a routine for updating the correction retard amount,
FIG. 12 is a flowchart of the learning control routine, FIG. 13 is a flowchart of the two-dimensional interpolation routine, and FIG. 14 is a flowchart of the learning control routine.
Fig. 15 is a flowchart showing the details of the ignition timing;
Fig. 6 is a diagram similar to Fig. 3, showing the relationship between the engine rotation speed and the ignition timing, the corrected retardation amount, and the learning retardation amount, and Fig. 17 explains the ignition timing in 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... Sotting sensor, 32... Engine rotation angle sensor, 34... Electronic control circuit. Agent Tatsuyuki Unuma (and 2 others) Figure 1 Figure 2! Figure 3 Esozoshi Kaisoftyou @ Figure 6 Figure 7 Figure 8 Figure 9 Figure 11 Figure 12 Figure 15 Tokiho Hakitori, 56° Figure 16

Claims (3)

[Claims] (1) Within the knocking control range above a predetermined load, the basic ignition advance angle determined by the engine speed and load is determined by learning control and determined by the engine speed and load in order to bring the knocking level to the specified level. Knocking is controlled by subtracting the sum of the learning retardation amount to be changed and the corrected retardation amount, which retards the ignition timing when knocking occurs and advances the ignition timing when knocking no longer occurs, and at the same time controls the knocking when the load is lower than the predetermined load. (7) Knocking control method for an internal combustion engine in which the corrected retard amount is set to zero within the knock non-control region, characterized in that the corrected retard amount is set to a predetermined value exceeding zero within the knock non-control region. A knocking control method for an internal combustion engine. (2) The knocking control method for an internal combustion engine according to claim 1, characterized in that the learning retardation amount is set so that the corrected retardation amount falls within a predetermined range within the knocking control region. (3) The correction/retard amount in the knock non-control region is a value within a predetermined range of the correction retard amount in the knock control region. Knocking control method for an internal combustion engine as described in .