JPS62189372A - Ignition timing control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To enable promotion of prevention of knocking, by a method wherein, when one cylinder is transferred to a knock inducing condition attendant with a rapid decrease in rotation of an engine, the other cylinders are also corrected according to a corrected ignition delay angle amount serving as a lower limit value. CONSTITUTION:In a control circuit 19, knocking is detected at each cylinder of an engine 1 from an output from a knock sensor 18, and a condition under which knocking is apt to occur is decided from continuance of a rapid change in rotation of the engine. When a cylinder corresponds to the condition, a limit value on the advancing angle side in a delay angle correction amount is immediately set to a delay angle correction amount corrected at a present time, and the delay angle amounts of other cylinders are also reset along therewith. Thus, when a cylinder is transferred to a knock inducing condition, delay angle processing of an ignition timing at each cylinder is extremely rapidly effected to prevent the occurrence of knocking.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an ignition timing control device that improves drivability while suppressing knocking in an internal combustion engine such as an automobile.

(Prior Art) The ignition timing of an internal combustion engine needs to be determined depending on the state of the engine so that the engine can be operated optimally.

Considering engine efficiency and fuel consumption in −C, the minimum advance angle at maximum l・rut, so-called M B T (Minimum
ad-vance for Be5t Torque
) It is known that it is best to ignite near MBT, and it is necessary to change the ignition timing to MBT depending on the engine condition.

However, in certain engine conditions, advancing the ignition timing causes knocking, making it impossible to operate the engine stably. For example, knocking is likely to occur during transient operation.

Therefore, as a control device designed to avoid knocking during transient operation, there is known a control device as described in, for example, Japanese Patent Laid-Open No. 60-26170. This device determines the acceleration state of the engine, and when it is determined that the engine is in the acceleration state, reads out the retardation correction amount that is assigned in advance according to the throttle opening and the amount of change in the throttle opening. Based on this, the basic ignition timing is corrected and this value is used as the actual ignition timing to avoid knocking.

(Problem to be solved by this invention) However,
In such conventional ignition timing control devices, the basic ignition timing is corrected based on a predetermined retardation correction amount when the engine accelerates. If a gear shift (with the valve opening unchanged) is performed, there may be a large difference in the required retardation correction amount to keep the knocking level at a constant level with respect to the engine speed, or there may be a sudden change in the engine speed. The engine is placed under a high load due to a drop in rotational speed and the inflow of air into the intake pipe due to inertial force (hereinafter referred to as knock inducing conditions). There was a problem in that the retardation correction could not be performed and knocking occurred.

(Objective of the Invention) Therefore, the present invention predicts the occurrence of knock from the continuation of rapid changes in engine rotation, and sets the limit value on the advance side of the retard angle correction amount to the currently corrected retard angle correction amount for a predetermined period. At the same time, by immediately resetting the retardation correction amount for other cylinders in response to this, the ignition timing for each cylinder is retarded extremely quickly when knocking trigger conditions occur, thereby speeding up the avoidance of knocking and improving engine performance. The aim is to improve the operational control of

(Means for Solving the Problems) In order to achieve the above object, the ignition timing control device for an internal combustion engine according to the present invention has an operating state detection system that detects the operating state of the engine, as shown in FIG. means a, knock detection means for detecting knocking occurring in the engine, and condition determination means C for determining whether or not the engine has transitioned to a predetermined knock-inducing condition based on the output of the operating state detection means a. , a correction amount calculation means d that calculates a retardation correction amount for each cylinder to correct the ignition timing to the retard side so as to suppress knocking to a predetermined level; A changing means e predicts the occurrence and changes the limit value on the advance side of the retardation correction amount, sets the basic ignition timing based on the driving condition, corrects it according to the retardation correction amount, and changes the engine an ignition timing setting means f which performs the correction based on the output of the changing means e when the transition to a predetermined knock inducing condition; and an ignition means g which ignites the air-fuel mixture based on the output of the ignition timing setting means f.
It is equipped with.

(Operation) In the present invention, knocking is detected for each cylinder, and conditions where knocking is likely to occur (knock inducing conditions) are determined from the continuation of rapid changes in engine rotation. When this condition is met, the advance side limit value of the retard angle correction amount is immediately added to the currently corrected retard angle correction amount, and the retard angle correction amounts of other cylinders are also reset accordingly. .

Therefore, when the knock-inducing condition is reached, the ignition timing for each cylinder is retarded extremely quickly, and knocking can be avoided more quickly.

(Example) Hereinafter, the present invention will be explained based on the drawings.

2 to 12 are diagrams showing an embodiment of the present invention.

First, the configuration will be explained. In FIG. 2, reference numeral 1 denotes an engine. Intake air is supplied to each cylinder through an intake pipe 3 from an air cleaner (not shown), and fuel is injected by an injector 5 based on an injection signal. 7 spark plugs for each cylinder
The spark plug 7 is supplied with high voltage pulses from the ignitor 11 via the distributor 9. The spark plug 7, the distributor 9, and the ignitor 11 constitute an ignition means 13 that ignites the air-fuel mixture, and the ignition means 13 generates and discharges a high-voltage pulse based on the ignition signal Sp. Then, the air-fuel mixture in the cylinder is ignited and exploded by the high-pressure pulse discharge, and is discharged through the exhaust pipe 15 as exhaust gas.

The intake air flow rate Qa is detected by an air flow sensor 16 and controlled by a throttle valve 17 in the intake pipe 3. The combustion pressure of the engine 1 is detected by a knock sensor 18, which is composed of a pressure element, a magnetostrictive element, etc., and is provided for each cylinder.The output S of the knock sensor 18 is input to a control circuit (control unit) 19. control unit 1
9 determines whether or not knocking has occurred in each cylinder based on the output S of the knock sensor 18.

Further, a pair of crank angle sensors 20 and 21 are respectively attached to the distributor 9, one crank angle sensor 20 discriminates each cylinder, and the other crank angle sensor 21 detects the crank angle CA.

That is, one crank angle sensor 20 generates one pulse (hereinafter referred to as REF signal) every time the distributor shaft rotates 60 degrees, that is, every time the crankshaft rotates at a crank angle CA of 120 degrees.

The rising position of this pulse is, for example, 70° crank angle CA before the top dead center (TDC) of each cylinder, and the pulse width (crank angle CA from rising to falling) differs for each cylinder. The other crank angle sensor 21 generates 360 pulses every time the distributor shaft rotates once, and thus one rising or falling pulse (hereinafter referred to as a PoS signal) for every 1° crank angle CA.

Air flow sensor 16 and crank angle sensor 20°2
1 constitutes a driving state detecting means 22, and signals from the driving state detecting means 22 and the knock sensor 18 are input to a control unit 19. The control unit 19 performs ignition timing control (
There are other injection amount controls, but they are omitted here).

In addition to the above, the engine is usually equipped with various sensors such as an intake air temperature sensor that detects the operating state, and the control unit 19 also controls fuel injection, etc., but these are not directly related to the present invention. , all of these will be omitted in the following explanation.

FIG. 3 is a block diagram showing an example of the configuration of the control unit 19.

In this figure, the intake air amount signal from the air flow sensor 16 is sent to the analog multiplexer 32 via the buffer 30, and the micro-blossoming unit (
A
After being converted into a digital signal by the /D converter 34, it is taken into the microcomputer via the input/output port 36.

The REF signal from the crank angle sensor 20 is sent to the buffer 3
8 to an interrupt request signal forming circuit 40 and a cylinder discriminating circuit 41. Further, the PO3 signal from the crank angle sensor 21 is transmitted via a buffer 42 to the signal forming circuit 40 and the engine rotation speed signal forming circuit 4.
4 is input. The cylinder discrimination circuit 41 discriminates the currently ignited cylinder from the pulse width of the REF signal (crank angle CA from rise to fall), forms a corresponding double code, and sends it to the microcomputer via the input/output port 46. .

The interrupt request signal forming circuit 40 receives the REF signal and the Po
Interrupt request signals are generated for each predetermined crank angle CA from the S signal, and these interrupt request signals are input into the microcomputer via the input/output port 46. The engine rotational speed signal forming circuit 44 forms a binary signal representing the engine rotational speed Ne from the period of the PO8 signal. This binary signal is sent into the microcomputer via the input/output port 46.

The output signal S from the knock sensor 18 is input to the peak hold circuit 50 via a circuit 48 consisting of a buffer for impedance conversion and a bandpass filter through which the knocking-specific frequency band (7 to 8k) Iz) can pass. Ru. The peak hold circuit 50 receives a "1" level signal from the MPU 62 via the line 52 and the input/output port 46, and the peak hold circuit 50 receives a signal of "1" level from the MPU 62 through the line 52 and the input/output port 46. When the knock gate is opened, the maximum amplitude value (peak value a) of the output signal S from the knock sensor 18 is held. The output of the peak hold circuit 50 is converted into a binary signal by the A/D converter 54 and sent to the microcomputer via the input/output port 46.

However, the start of A/D conversion of the A/D converter 54 is
This is performed by an A/D conversion activation signal applied from the MPU 62 via the input/output port 46 and line 56.

Furthermore, when the A/D conversion is completed, the A/D converter 54 notifies the microcomputer of the completion of the A/D conversion via the line 58 and the input/output port 46. Therefore, the knock sensor 18, buffer filter 48, peak hold circuit 50, and A/D converter 58 collectively constitute knock detection means.

On the other hand, when the ignition signal Sp is output from the MPU 62 to the drive circuit 60 via the input/output boat 46, this is converted into a drive signal to energize the ignitor 11, and the ignition signal Sp
Ignition control is performed accordingly.

The microcomputer has an input/output port of 36.46, MP
It mainly consists of U62, random access memory (RAM) 64, read-only memory (ROM) 66, a clock generation circuit (not shown), and a path 68 connecting these. Execute processing. Also, R.O.
The M66 has a basic value determined by the engine speed Ne and the intake air amount per engine rotation (intake pipe pressure when using a pressure sensor that detects the pressure on the downstream side of the throttle valve 17 instead of the air flow sensor 16). Ignition timing SAo
is memorized. Furthermore, the control unit 19
is a microcomputer, buffer 30.38.42,
Buffer filter 48, peak hold circuit 50, A/
It is composed of a D converter 34, 54, a cylinder discrimination circuit 41, an interrupt request signal formation circuit 40, an engine rotation speed signal formation circuit 44, an analog multiplexer 32, and a drive circuit 60, and includes a condition discrimination means, a change means, and a correction amount calculation. It has a function as a means and an ignition timing setting means.

Next, the effect will be explained.

First, the processing routine according to this embodiment will be explained. In the following explanation, the most convenient numerical values will be used to avoid complication, but the present invention is not limited to these numerical values, and the optimum value will be selected for each engine. Ru.

Interrupt request signals for each specific crank angle CA predetermined from the interrupt request signal forming circuit 40, that is, an interrupt at the rising edge of the REF signal (hereinafter referred to as REF interrupt) and an interrupt at ATDC 30° and 60° (hereinafter referred to as angle interrupt) When the MPU 62 receives the input request signal, the MPU 62 executes the interrupt processing routine shown in FIGS. 4 and 5. The main routine shown in FIG. 4 is mainly for controlling the ignition timing SA by determining the timing to hold the peak of the signal Sl output from the knock sensor 18 and knocking. The subroutine shows a routine for resetting the count value m of the crank angle counter.

When the REF interrupt request signal is input, the routine shown in FIG. 5 is executed, the count value m is reset in step 70, and the process returns to the main routine. Since the rise of the REF signal is output at a crank angle CA of 70° before the TDC of each cylinder, the curvature straight line m is reset at a crank angle CA of 70° before the top dead center of each cylinder.

On the other hand, when an angle interrupt request is input, the main routine shown in FIG. 4 is executed, and first, in step 72, the engine speed Ne determined by the engine speed signal forming circuit 44 is fetched. Next, in step 80, the count value m of the crank angle counter is incremented by +1.

Here, the relationship between the count value m and the crank angle CA is shown in FIG. 9(A).

Next, in step 86, it is determined whether the count value m is 2, that is, whether the piston has reached the TDC of each cylinder. If it is not the TDC of each cylinder, the process proceeds to step 92, and if it is the TDC of each cylinder, the cylinder discrimination result is read from the input/output boat 46 in step 87, and the cylinder discrimination result is set as the cylinder number i. In step 88, the knock gate of the peak hold circuit 50 is opened to start peak hold, and in step 90, time t for closing the knock gate and ending peak hold is calculated and set in conveyor register A.

At time t, when a cent is placed on conveyor register A,
The time-number ticking routine shown in FIG. 6 is executed, and A/D conversion of the peak hold value is started in step 102. When the A/D conversion is completed, the A/D converter 54
A D conversion end notification is input, and in response to this notification, the A/D conversion end interrupt routine shown in FIG. 7 is executed. In this routine, in step 104, the A/D conversion value is stored as a peak value a in a predetermined area of the RAM 64, and in step 106, the knock gate is closed, and the routine returns. The timing of closing the knock gate oven in the above routine is shown in FIGS. 9(B) and 9(C).

In step 92, it is determined whether the count value m is 3, that is, whether the piston has reached 30° A'I'DC of each cylinder. If it is not 30° ATDC, the process proceeds to step 98. On the other hand, when the angle is 30° ATDC, in step 94, a knocking control process is executed in which it is determined whether knocking has occurred and a corrected retardation amount 5Ari is calculated. This knocking control process is performed in the first step, which will be explained later.
This is executed in the interrupt processing routine every 30' ATDC in the θ diagram (see FIG. 9(D)).

In step 96, in the main routine (not shown),
Basic ignition timing SA calculated by interpolation from the basic ignition timing map stored in OM66.

and a corrected retardation amount 5Ari assigned to each cylinder for knock control. + (i+1 is the cylinder number i and means the next cylinder. Therefore, when i+1=6, it is considered as O) and the effective ignition timing 5A (=SAo-3Ar i
, 1), and calculates the ignitor on time from the effective ignition timing SA and the current time, and stores it in the conveyor register B (see FIG. 9(E)). In the following step 98, if the count value m is 1 or not, that is, if the piston is not at 60° ATDC of each cylinder, the process returns to the main routine, and if it is 60' ATDC, the ignitor is turned off according to the effective ignition timing SA and the current time. The time is calculated and set in conveyor register B, and the process returns to the main routine.

When the time set in steps 96 and 100 is reached, the time-number ticking processing routine shown in FIG. turns on the ignitor in step 110,
If the ignitor is turned off, the ignitor is turned off in step 112 and the process returns. As a result, the engine is ignited at 31 JISA during actual ignition.

Next, the contents of the knocking control process in step 94 in FIG. 4 will be explained in detail based on the flowchart showing the subroutine in FIG. 10.

This routine determines conditions where knocking is likely to occur (corresponding to knock-inducing conditions) based on the deceleration of engine rotation and its duration, and when that condition is met, the advance side of the retard angle correction amount is set for a predetermined period. By setting the limit value to the currently corrected correction amount and immediately resetting the retardation correction amounts for other cylinders accordingly, knocking can be avoided more quickly.

First, in step 122, the FLAG
is 1, and when FLAG=0, in step 124, the engine rotation change ΔN is calculated according to the following formula (■), and this is set to a predetermined value r (for example, 10r, p,
/IGN, usually 10~-5Or, p.

button/IGN level).

ΔN=Ne−Neb ・・・・・・■ However, when Ne: Current engine speed Neb: Previous engine speed ΔNor, it is determined that the degree of damping is large, and the process proceeds to step 130, and ΔN: Sr In this case, in step 126, the count value CT for counting the elapsed time of knock inducing conditions and sudden deceleration is set to CT=IO/IGN, and in step 1
28, set FLAG to 0.

On the other hand, in step 130, the count value CT is incremented by 1, and in step 132, it is determined whether or not the count value CT is O. When CT=O, the process advances to step 134, and C
If T≠0, the process advances to step 128. Step 134
Then, the count value CT is the initial value CT=255
/ I GN and FLAG in step 136.
is set to 1 to indicate that knocking is likely to occur (knock inducing condition), and this routine ends.

On the other hand, if step 128 is passed, then in step 142 the slice level S of the peak value detected this time (corresponding to the cylinder that was ignited last time) is used for knock determination.
Compare with L. When a>SL, it is determined that knocking is occurring and the process proceeds to step 144; when a≦SL, it is determined that knocking is not occurring and step 14
Proceed to step 6. In step 144, as shown in the following equation
, is the basic retardation bone Y (for example,
0°025°) to perform retardation correction.

SA r i-, 4-SA r i-, +y =”■
On the other hand, in step 146, as shown in the following equation 〇, the basic advance angle X (for example, 0.25
The lead angle is corrected by subtracting .

5Ari, '-5Ari-, -X ------
-■ Next, in step 148, the newly calculated retardation correction ff1SAri-1 is set to a predetermined upper limit (for example, 1
5°) or a lower limit value (for example, 0゛), and if the value is exceeded, the retard angle correction amount 5Ari-1 is determined.
is limited to this upper limit value or lower limit value, and the process proceeds to step 150. In step 150, FLAG is checked and FLAG is checked.
When AG=O, there is no knock inducing condition, so this routine ends. When FLAG-1, in step 151, the retard angle correction amount 5 corrected in steps 144 to 148 is
Ari-, is set as the lower limit (i1! (retard limit value)), and the advance angle correction amount 5Arj (however, j
≠1-1). Note that detailed processing of this step 151 will be explained later with reference to FIG. 11.

Next, in step 152, the count value CT is decremented by 1, and in step 154, the count value CT is compared with O. When CT≠0, this routine ends and CT=
If it is 0, in step 162 the count value CT is set to CT=1.
The flag is set to 0, and in step 164, FLAG is set to 0, and this routine ends.

Although not shown in the flowchart, at least CT=O1FLAG=0 is set when initializing each control circuit including the control unit 19 when the power is turned on (when the ignition key is turned on).

Next, the process of step 151 will be explained using FIG. 11.

As already mentioned, this routine sets the currently corrected corrected retard amount 5Arl-+ as the lower limit value (advance limit value), and calculates the retard correction amount SAr j (j#
1-1) is corrected.

First, in step 200, j is initialized (j=0). Next, in step 202, it is compared whether j is the cylinder (cylinder number 1-1) for which the current retardation correction amount was corrected;
If =i-1, jump to step 208. j
In the case of #i-1, proceed to the steering knob 204 and set the retard angle correction amount 5Arj and SAr! −+, 5Arj is SAr
+-, if the angle is more retarded or the same, jump to step 208; if 5Arj is on the advance side, proceed to step 206, and replace the value of 5Arj with the value of 5Ari-.

As a result, the retard angle correction amount 5Arj of the cylinder that is advanced with respect to 5Ari-+ is corrected to the retard side, and 5Ari-+
, is taken as the value of . That is, in order to avoid knocking, the advance angle of the retard angle correction amount is determined, and only the advanced cylinders are corrected to the retard side.

In step 208, the value of j is increased by 1, and if j<5 in step 210, the process returns to step 202 and the same process is performed for the next cylinder until j=6.
When j≧6, this routine is completed for one winter. In this way, 5Arj corrections are made for all cylinders.

Next, the actual engine situation resulting from the execution of the main routine shown in FIG. 10 will be explained.

If the acceleration, steady state, or slow deceleration state continues, this routine proceeds to steps 122, 124, and 126;
128.142.144 (146), 14B, 150
is executed. That is, CT=10 (initial value), FL
AG=O is maintained and normal ignition timing correction is performed.

If sudden deceleration is detected, step 122.130.13
2, 128, etc. are executed. This state is 1
Steps 134, 136, 142, old, etc. are executed only after m consecutive 0 ignitions (until the Count value becomes 0).

Then, in these steps, the knocking occurrence prediction period (
255 ignition) to the count value, FLAG=1
(Indicates that the conditions are such that knocking is likely to occur)
shall be.

On the other hand, if the sudden deceleration does not continue for 1O ignition, it is not determined that the condition is likely to cause knocking, and FLAC=O is maintained and normal correction control is continued.

In addition, if FLAC becomes -1, this routine executes steps 122.142.144 (146) and 14B.
, 150.151 , i52.154.156.158
．． 160 is executed. This means that the count value CT is 225
The process continues from 0 to 0. At this time, step 15
1, the corrected 5Ari- and the retardation correction ff1sArj (j≠1-1) of other cylinders that are more advanced are 5A
The value is ri-. Then, the count value CT is CT
=O, step 162.1 from step 154
64 is executed, count value CT=0 (initial value),
FLAC;=O, and normal correction control will be executed from then on.

Next, FIG. 12 shows the peak value a (see (B) in FIG. 12) and the retardation correction amount S A ri (see (B) in FIG. 12) accompanying changes in engine speed Ne and load (see (A) in FIG. 1
FIG. 2 is a diagram showing changes over time in (see (C) in FIG. 2).

First, as shown by (A, ) in Fig. 12, when the operating state continues such that the load is constant and the rotational speed Ne gradually increases, the retardation correction amount 5Ari is calculated based on the above formula 0.
Since the value gradually decreases, the ignition timing SA is slowly corrected (see (C) in FIG. 12).

On the other hand, when a gear change is performed with an engine equipped with an automatic transmission with a constant throttle opening, the engine speed increases due to the sudden drop in engine rotation and the inflow of air into the intake pipe due to inertia. When the load state shifts to a knock-inducing condition in which knocking is predicted to occur (see (A) in Figure 12), in this case, conventionally, normal retardation correction is performed as shown by the broken line, so the retardation The corners were slow, allowing knocking to occur.

On the other hand, in this embodiment, when a knock inducing condition is detected, during that period (during the 255 ignition period), the corrected retard angle correction amount 5Art-t is set as the lower limit value (advance angle limit value) and normal retardation in other cylinders is performed. The angle correction amount 5Arj (j=i-1) is corrected to speed up the prevention of knocking in other cylinders (see (B) and (C) in Figure 12).

Therefore, the time required to avoid knocking and the level of knocking can be made much smaller than in the past, and the drivability of the engine can be improved.

FIG. 13 is a diagram showing a second embodiment of the present invention.

This embodiment differs from the first embodiment in that step 166.16B is added following step 136 to perform recoup. The rest is the same as the first embodiment,
The same step numbers are marked.

That is, after step 136 is executed, in step 166, a value that is most retarded than the retard angle correction amount 5Aro-5 for each cylinder is determined (the detailed flow of this step is common, so a detailed explanation will be omitted). Next, in step 168, the value is stored as the retardation correction amount for each cylinder. Thereafter, the process proceeds to step 142.

The operation of this embodiment differs from the first embodiment in the following points.

After a sudden deceleration is detected and this state continues for 10 ignitions, (the count value CT becomes CT=0 and the process advances from step 132 to step 134), step 134.136.1
66.168.142... are executed. At this time, the expected knocking period (255 ignitions) is added to the count value CT and set to FLAC;=1, and the most retarded value among the retard angle correction values 5Aro-5 for each cylinder is set as the advance angle limit. Store as a value in the retard angle correction amount. As a result, when the knocking prediction period is reached (when the knock inducing condition is reached), the correction amount for the other cylinders is immediately unified with the correction amount for the most retarded cylinder, so that knocking is further avoided than in the first embodiment. is accelerated.

(Effects) According to the present invention, when the knock-inducing condition occurs due to a sudden drop in engine speed, the corrected retardation correction amount is set as the lower limit and the other cylinders are also corrected accordingly. This can speed up the avoidance of engine problems and improve engine drivability.

In addition, in the second embodiment, since the retardation correction amount for the most retarded cylinder is immediately added to the retardation correction amount for other cylinders, knocking is further reduced compared to the first embodiment. Can speed up evasion.

[Brief explanation of drawings]

FIG. 1 is a basic conceptual diagram of the present invention, FIGS. 2 to 12 are diagrams showing an embodiment of the present invention, FIG. 2 is an overall configuration diagram thereof, FIG. 3 is a block diagram of its control circuit, and FIG. 4 to 8 are flowcharts showing each processing routine executed by the control circuit, FIG. 9 is a timing chart showing the operation of the control circuit, and FIG. 10 is a flowchart showing the knocking control processing execution program of FIG. 4. FIG. 11 is a flowchart showing the subroutine of the process in step 151 in FIG. 10, FIG. 12 is a timing chart for explaining its operation, and FIG. 13 is a knocking control process execution showing a second embodiment of the present invention. It is a flowchart showing a program. 1... Engine, 13... Ignition means, 18.48.50.54... Knock detection means,
19... Control unit (condition determining means, changing means, correction amount calculating means, ignition time setting means), 22... Operating state detecting means.

Claims (1)

[Scope of Claims] a) operating state detection means for detecting the operating state of the engine; b) knock detection means for detecting knocking occurring in the engine; d) calculating a retardation correction amount for each cylinder to retard the ignition timing so as to suppress knocking to a predetermined level; correction amount calculating means; e) changing means for predicting the occurrence of knocking and changing the limit value on the advance side of the retardation correction amount when the engine shifts to a predetermined knock-inducing condition; f) based on the operating state. ignition timing setting means that sets the basic ignition timing according to the retardation correction amount, and performs the correction based on the output of the changing means when the engine shifts to a predetermined knock-inducing condition; g) An ignition timing control device for an internal combustion engine, comprising: ignition means for igniting an air-fuel mixture based on the output of the ignition timing setting means.