JP2003003941A - Ignition timing control apparatus for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ignition timing control apparatus for an internal combustion engine, which can easily implement the prevention of the generation of knocking as well as the prevention of unnecessary lowering of engine torque. SOLUTION: This apparatus calculates reference ignition timing ABSE based on an operating state of an internal combustion engine, learns a knock retard amount AKNK depending on generating states of knocking of the engine to prevent the generation of the knocking, and sets required ignition timing Acal of ignition timing relating to the engine control while reflecting the knock delay amount AKNK to the reference ignition timing ABSE. Setting modes of the required ignition timing Acl is alternatively switched from/to 'ABSE+ AKNK' (step S201) to/from 'ABSE' (step S202) every ignition. Therefore, the knock retard amount AKNK is reflected to the reference ignition timing ABSE by thinning the ignition every other time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition timing control device for an internal combustion engine, which controls the ignition timing according to the knocking occurrence condition in the internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, as an ignition timing control device of this type, for example, there is a device described in Japanese Patent Laid-Open No. 2000-73925.

In this device, first, the basic ignition timing is calculated based on the operating state of the internal combustion engine, and further, the calculated basic ignition timing is learned according to the occurrence state of knocking in order to suppress the occurrence of knocking. The ignition timing required for the internal combustion engine is obtained by reflecting the angular amount. The retard amount is learned so that the ignition timing is retarded when knocking occurs, and conversely, the ignition timing is gradually advanced when knocking does not occur. Amount.

However, even if the knocking does not occur after the ignition timing is greatly retarded due to strong knocking continuously or even in a single shot, the subsequent ignition timing is constant. When advancing at the speed of, the following problems may occur. That is, in the period until the ignition timing retarded by the occurrence of knocking is gradually advanced and reaches the ignition timing before the knocking occurrence, the ignition timing is retarded even though knocking does not occur. Therefore, if this period is prolonged, the engine torque is unnecessarily reduced.

Therefore, in the above device, in order to suppress such an unnecessary decrease in engine torque, the speed at which the ignition timing is retarded or advanced is changed according to the knocking occurrence state. For example, even if the ignition timing is greatly retarded in response to the occurrence of knocking, and if the knocking is difficult to occur thereafter, the advance speed is set to a higher speed. As a result, when knocking is unlikely to occur and knocking does not occur, the ignition timing is quickly advanced, and an unnecessary decrease in engine torque is suppressed accordingly. .

[0006]

As described above, the occurrence of knocking is suppressed by variably setting the retarding speed or the advancing speed of the ignition timing according to the knocking occurrence situation.
It is possible to achieve both suppression of unnecessary decrease in engine torque due to retardation of ignition timing.

However, in order to do so, it is necessary to detect various environmental conditions and engine conditions related to the occurrence of knocking in detail, and to obtain the knocking occurrence state at each time and the retarding speed or advancing speed corresponding thereto. However, there are many practical problems such as complicated calculation being required.

The present invention has been made in view of the above circumstances, and an object thereof is to ignite an internal combustion engine which can more easily achieve both suppression of knocking occurrence and suppression of unnecessary reduction of engine torque. It is to provide a timing control device.

[0009]

[Means for Solving the Problems] Means for achieving the above-mentioned objects and their effects will be described below. First, the invention according to claim 1 calculates the basic ignition timing based on the operating state of the internal combustion engine, and learns a retard amount corresponding to the occurrence state of the engine in order to suppress the occurrence of knocking. In an ignition timing control device for an internal combustion engine that controls the engine ignition timing while reflecting the learned retard angle amount on the basic ignition timing, the reflection of the learned retard angle amount on the basic ignition timing is performed every predetermined ignition times. The gist is to provide a thinning control means for thinning control.

When the ignition timing is retarded in accordance with the occurrence of knocking, the ignition timing is not necessarily retarded uniformly for all ignitions. For example, the ignition timing is not retarded once every two ignitions. It has been confirmed by the present inventors that even if the angle control is performed intermittently, substantially the same suppressing effect on the occurrence of knocking can be obtained. Therefore, according to the above-described configuration in which the reflection amount is reflected in the basic ignition timing for every predetermined number of ignitions, a knocking suppression effect that is substantially the same as the case where the same ignition amount is reflected in the ignition timing in all ignitions is obtained. In addition to being obtained, the reduction of the engine torque is suppressed by the amount that the ignition timing in the ignition in which the reflection of the retard amount is thinned is advanced. Therefore, it is possible to more easily achieve both suppression of knocking occurrence and suppression of unnecessary reduction in engine torque. The predetermined number of ignitions does not necessarily mean a constant number of ignitions, and the number may be changed according to the control cycle of the thinning control.

The invention described in claim 2 is the same as claim 1.
In the ignition timing control device for an internal combustion engine according to claim 1, the knocking occurrence frequency of the engine is obtained, and when the obtained knocking occurrence frequency is equal to or higher than a predetermined frequency, the thinning control inhibiting means for inhibiting the thinning control by the thinning control means. It is the gist to further provide.

The invention described in claim 3 is the same as claim 1
In the ignition timing control device for an internal combustion engine according to claim 1, the knocking strength and the knocking occurrence frequency of the engine are respectively determined, and when the obtained knocking strength and knocking occurrence frequency are both above a predetermined level, the thinning control by the thinning control means is performed. The gist of the present invention is to further include a thinning-out control prohibiting means for prohibiting.

According to the structure of the present invention as set forth in claim 2 or 3, when the knocking cannot be suitably suppressed, such as when the knocking occurs frequently or when the strength thereof is large, the delay occurs. The thinning of the reflection of the angular amount is prohibited. At this time, because the ignition retard amount is reflected in the ignition timing in all ignitions,
The occurrence of knocking can be suppressed more quickly.

The invention described in claim 4 is the same as that of claim 2
Alternatively, in the ignition timing control device for an internal combustion engine as described in 3, the thinning-out control is performed so that the learned retard angle amount becomes different between a period in which the thinning-out control is prohibited and another period. The gist of the present invention is to further include a correction unit that corrects at least one of the retard amount during the period in which the control is prohibited and the retard amount during the other period.

According to the above-mentioned structure, the retard amount reflected on the basic ignition timing is separately set as the amount suitable for each period in the period in which the thinning of the retard amount is prohibited and the other period. It will be possible. As a result, the degree of freedom in setting the ignition timing can be increased, and it is possible to achieve a more suitable balance between the suppression of knocking occurrence and the suppression of an unnecessary decrease in engine torque.

The invention according to claim 5 is the same as claim 1.
The ignition timing control device for an internal combustion engine according to any one of claims 1 to 4, wherein the internal combustion engine has a plurality of cylinders, and the thinning control means executes thinning control for each of the predetermined ignition times for each cylinder. What to do is the gist.

According to the above construction, it is possible to achieve well-balanced suppression of knocking occurrence in all of the plurality of cylinders.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an ignition timing control device for an internal combustion engine according to the present invention will be described below.

FIG. 1 shows a schematic configuration of an internal combustion engine to which an ignition timing control device according to this embodiment is applied.
As shown in FIG. 1, in the internal combustion engine 10, a knock sensor 21 that outputs a knock signal KCS according to the intensity of vibration (engine vibration) generated in the internal combustion engine 10 is provided near the combustion chamber 12. It is provided. Further, in the vicinity of the crankshaft 13, its rotation speed (engine rotation speed) NE
A rotation speed sensor 22 that outputs a signal according to the above is provided. On the other hand, the surge tank 14 provided in the intake passage 11 has a pressure PM of intake air in the surge tank 14.
An intake pressure sensor 23 that outputs a signal according to the above is provided. An appropriate pulse signal (cam angle signal) CA corresponding to a predetermined cam angle (here, the cam angle corresponding to the compression top dead center) is provided in the vicinity of the cam shaft 15 that is connected to and driven by the crankshaft 13. Output cam angle sensor 2
4 are provided.

Further, the internal combustion engine 10 is provided with a spark plug 16 for igniting the air-fuel mixture drawn into the combustion chamber 12. An ignition coil 17 and an igniter 18 are electrically connected to the ignition plug 16. The igniter 18 drives the ignition coil 17 on the basis of an input ignition signal to execute an ignition operation by the ignition plug 16.

The ignition timing control device according to the present embodiment is provided with an electronic control device 30 including, for example, a microcomputer, and the electronic control device 30 includes:
The output signals of the sensors 21 to 24 are fetched. Then, the electronic control unit 30 performs various calculations based on these output signals, and based on the calculation results, ignition timing control through drive control of the igniter 18, etc.
Performs various controls related to engine control.

Further, the electronic control unit 30 determines, based on the knock signal KCS detected by the knock sensor 21,
Whether or not knocking has occurred in the internal combustion engine 10 and its strength are determined.

FIG. 2 shows the relationship between the knock signal KCS and the intensity of the engine vibration. As shown in FIG. 2, as the strength of engine vibration increases, the knock signal KCS is output as a larger value. Then, the electronic control unit 30
Determines that knocking of the internal combustion engine 10 occurs when the knock signal KCS becomes equal to or higher than a predetermined value K1 (a value corresponding to the predetermined strength W1 regarding the strength of engine vibration). Further, in the device 30, the knock signal KCS has the predetermined value K1.
When the value is equal to or more than the predetermined value K2 (a value corresponding to the predetermined strength W2 regarding the strength of the engine vibration), it is determined that knocking with a relatively small strength (hereinafter, "small knock") occurs. . On the other hand, when the knock signal KCS is a value equal to or larger than the predetermined value K2, the device 30 determines that knocking with a large intensity (hereinafter, “large knock”) occurs. In the device of the present embodiment, the presence / absence of knocking, the strength of knocking, and the like thus determined are also used for the ignition timing control.

The ignition timing control system of the present embodiment calculates the basic ignition timing based on the engine speed NE and the intake air pressure PM, and at the same time, in order to suppress knocking of the internal combustion engine 10, the knock signal KCS and knocking occurrence are generated. The knock delay amount is learned according to the presence or absence of the knock, the knock intensity, and the knocking occurrence frequency described later. Then, the same device sets the ignition timing (required ignition timing) for engine control while reflecting the knock retard amount in the basic ignition timing. The basic ignition timing is set as a timing at which the engine torque becomes maximum when the influence of the knocking occurrence situation is not taken into consideration. That is, when the required ignition timing is corrected based on the engine environment other than knock, the basic ignition timing may be the time when the correction based on the engine environment is added.

FIG. 3 shows the results of the inventors' measurement of the transition of the peak value of the fluctuation speed of the pressure in the combustion chamber in each combustion stroke of the internal combustion engine. 3 (a) shows the transition of the peak value when the ignition timing is set to a timing at which knocking occurs, and FIG. 3 (b) shows the ignition timing with a predetermined retard amount every other ignition. The transition of the peak value when reflected is shown.

As is clear from FIG. 3, by reflecting a predetermined retardation amount every other ignition in the ignition timing at which knocking occurs, the peak of the fluctuation speed of the pressure in the combustion chamber can be suppressed, and by extension, the peak. The occurrence of knocking is suppressed.

Also, when the predetermined retard amount is uniformly reflected in the ignition timing at which the knocking occurs in all ignitions, it is almost the same as when the predetermined retard amount is reflected every other ignition. It has been confirmed by the present inventors that an equivalent peak suppression effect can be obtained, and thus an almost equivalent knocking suppression effect can be obtained.

Therefore, in the device of the present embodiment, when the required ignition timing is set, the reflection of the knock retard amount to the basic ignition timing is thinned out every other ignition. As a result, in all ignitions, a knocking suppression effect that is almost the same as when the knocking retard amount is reflected in the required ignition timing is obtained, and the required ignition timing in the ignition in which the reflection of the knocking retard amount is thinned out is The decrease in the engine torque is suppressed by the amount of advance.

Further, in the device of the present embodiment, the thinning of the knock delay amount reflected can be suitably suppressed when a large knock has occurred and the knock frequency is high, that is, knocking. We try to ban it when it is gone. At this time, the knock retard amount is reflected in the required ignition timing for all ignitions.

The procedure of the ignition timing calculation process of this embodiment will be described below with reference to the flowcharts shown in FIGS. 4 and 5. The series of processes shown in FIGS. 4 and 5 is executed by the electronic control unit 30 as an interrupt process for each predetermined cycle (for example, for each crank angle).

As shown in FIG. 4, in this series of processes, first, the basic ignition timing ABSE is calculated from the map based on the engine speed NE and the intake air pressure PM (step S100). The map is based on the relationship between the engine speed NE and the intake air pressure PM, and the basic ignition timing ABS
It is a map for calculating E, and is an electronic control unit 3 in advance.
It is stored in 0.

After that, the engine speed NE and the intake air pressure P
The limit retard angle value AKMF is calculated from the map based on M and the limit retard angle amount AKMAX is calculated as a difference between the limit retard angle value AKMF and the basic ignition timing ABSE in the form of AKMAX ← AKMF-ABSE. (Step S10
1). The map is a map for calculating the limit retard value AKMF based on the relationship between the engine speed NE and the intake air pressure PM, and this map is also stored in the electronic control unit 30 in advance. In addition, the above limit retard angle AKM
AX is an amount that becomes the control limit of the knock retard amount,
It is calculated as an amount that reliably suppresses the occurrence of knocking.

After that, the following processing (step S1)
02 to S110), the knock control amount AKCS is calculated as an amount according to the knocking occurrence state. That is, first, it is determined whether knocking of the internal combustion engine 10 has occurred through the determination based on the knock signal KCS described above (step S102).

When it is determined that knocking has occurred (step S102: YES), the knock control amount AK is calculated from the map based on the knock signal KCS.
The knock basic amount AKCSB, which is the basic amount of CS, is calculated. The map is a map for calculating the knock basic amount AKCSB from the knock signal KCS, and this map is also stored in the electronic control unit 30 in advance. Further, the basic knock amount AKCSB is the knock signal KCS.
Is calculated as a larger value.

Thereafter, it is determined whether or not a large knock has occurred and the frequency of occurrence of knocking (hereinafter, "knock frequency") is high (step S104). Whether or not the knock frequency is high is determined based on the count value of the knock counter. This knock counter is a counter whose count value is incremented each time the ignition operation of the spark plug 16 is executed, and which is reset when knocking occurs. When the count value of the knock counter is equal to or less than a predetermined value (for example, in the case of a 4-cylinder internal combustion engine, a value corresponding to “4” in one cycle conversion), it is determined that the knock frequency is high. It

When it is determined that a large knock has occurred and the knock frequency is high (step S104: YES), the correction coefficient Ka is set to a predetermined value α (for example, "2"). (Step S105). On the other hand, when the large knock has not occurred or the knock frequency is small (step S104: NO), the correction coefficient Ka is set to "1" (step S106).

After the correction coefficient Ka is set in this way, the correction value Kn for the engine speed NE is set as follows based on the engine speed NE and the knock frequency (step S107). In addition, "° CA" shown below
Represents the crank angle. When the engine speed NE is less than the predetermined speed and the knock frequency is small, the correction value Kn is set to the predetermined value β1 (for example, 0.06 ° CA). When the engine speed NE is less than the predetermined speed and the knock frequency is high, the correction value Kn is set to the predetermined value β2 (for example, 0.12 ° CA). The correction value Kn is set to "0" when the engine speed NE is equal to or higher than the predetermined speed.

Then, the correction value Kp for the intake air pressure PM is set as follows based on the intake air pressure PM and the knock frequency (step S108). When the intake air pressure PM is less than the predetermined pressure and the knock frequency is small, the correction value Kp is set to the predetermined value γ1 (for example, 0.
06 ° CA). When the intake air pressure PM is less than the predetermined pressure and the knock frequency is high, the correction value Kp is set to the predetermined value γ2 (for example, 0.
12 ° CA). When the intake air pressure PM is equal to or higher than the predetermined pressure, the correction value Kp is set to "0".

Thus, the correction coefficient Ka and each correction value Kn,
After Kp is calculated, the knock control amount AKCS is in the form of AKCS ← AKCSB × Ka + Kn + Kp, that is, the knock basic amount AKCSB.
Is calculated as the amount corrected by the correction coefficient Ka and the respective correction values Kn and Kp (step S109).

On the other hand, if it is determined that knocking of the internal combustion engine 10 has not occurred (step S102: N
O), the knock control amount AKCS is subtracted and updated by a predetermined amount A1 (for example, 0.23 ° CA every 0.262 seconds) as in the following equation (step S110). AKCS ← AKCS-predetermined amount A1 By calculating or updating the knock control amount AKCS according to the presence or absence of knocking in this way, the knock control amount AKCS becomes larger in accordance with the current knocking state of the internal combustion engine 10. Is the amount that changes. Specifically, this knock control amount AKCS sets the required ignition timing to the retard side when knocking occurs, and conversely, when the knocking does not occur, the required ignition timing advances. It is an amount for controlling the ignition timing according to the occurrence situation of knocking at that time, such as setting the timing of.

After the knock control amount AKCS is calculated or updated in this way, as shown in FIG. 5, the knock control amount AKCS, the limit retard angle AKMAX, and the process (steps S112 to S114) described later are learned. Based on the knock learning amount AGKNK, the knock delay amount AK
NK is calculated by the following equation (step S111). AKNK ← AKMAX−AGKNK + AKCS That is, the knock retard amount AKNK is calculated as a value obtained by correcting the limit retard amount AKMAX with the knock learning amount AGKNK and the knock control amount AKCS.

Then, after that, the knock learning amount AGKN is calculated.
K is learned and updated as follows. That is, first, it is determined whether the knock control amount AKCS is less than a predetermined value A2, that is, a value obtained by performing a process of slowing the increase / decrease speed (step S112).

If it is determined that the smoothed value is less than the predetermined value A2 (step S112: YE
S), the knock learning amount AGKNK is subtracted / updated by a predetermined amount A3 in a mode of AGKNK ← AGKNK-predetermined amount A3 (step S113).

On the other hand, when it is determined that the smoothed value is the predetermined value A2 or more (step S112: NO),
The knock learning amount AGKNK is added / updated by a predetermined amount A4 in a mode of AGKNK ← AGKNK + predetermined amount A4 (step S114).

This knock learning amount AGKNK is set relatively small when knocking tends to occur frequently, and conversely is set relatively large when the number of knocking occurrences is small. Therefore, this knock learning amount A
GKNK is a value that reflects factors that have a steady influence on the occurrence of knocking, such as variations in the characteristics of the internal combustion engine 10 and changes over time. Specifically, the smaller the knock learning amount AGKNK, the more the requested ignition timing is set to the timing on the retard side.

After the knock learning amount AGKNK is updated in this manner, it is determined whether or not the thinning out of the reflection of the knock delay amount described above is prohibited. That is, first, it is determined whether or not a large knock has occurred (step S115),
Further, it is determined whether or not the knock frequency is high (step S116).

If it is determined that a large knock has occurred and the knock frequency is high (step S1
15 and S116: YES), the required ignition timing Acal
However, after being set in a mode such as Acal ← ABSE + AKNK, that is, as a timing in which the knocking retardation amount AKNK is reflected in the basic ignition timing ABSE (step S117), this processing is temporarily terminated. That is, in this case, the thinning of the reflection of the knock retard amount AKNK is prohibited.

On the other hand, if it is determined that a large knock has not occurred (step S115: NO), or if it is determined that a large knock has occurred but the knock frequency is low (step S115: YES and Step S11
6: NO), after the process of thinning out the reflection of the knocking delay amount AKNK is executed (step S118), this process is once ended.

Hereinafter, the processing procedure of the processing for thinning the reflection of the retard amount will be described with reference to the flowchart shown in FIG. It should be noted that this process is executed by the electronic control unit 30 as an interrupt process immediately before the execution of the ignition operation by the spark plug 16.

As shown in FIG. 6, in this process, it is first judged whether or not the count value of the thinning counter is "1" (step S200). Note that this thinning-out counter is a binary counter, and its count value is
In addition to being incremented each time the ignition operation by the ignition plug 16 is executed during execution of this processing,
This counter is reset to "0" when execution of this process is prohibited. When the count value of the thinning-out counter is "1", it is determined that the thinning-out of the knock retardation amount AKNK has not been thinned out at the time of the previous ignition.

When the count value of the thinning-out counter is "0" (step S200: NO),
The required ignition timing Acal is the basic ignition timing A according to the following equation.
It is set as the time when the knock retard amount AKNK is reflected in BSE (step S201). Acal ← ABSE + AKNK On the other hand, when the count value of the thinning-out counter is “1” (step S200: YES), the required ignition timing Acal is the basic ignition timing ABSE as shown below.
Is set (step S202). Acal ← ABSE By setting the required ignition timing Acal in this way, the required ignition timing Aca is reflected in the basic ignition timing ABSE so that the reflection of the knock retard amount AKNK is thinned out every other ignition.
l will be set.

FIG. 7 shows an example of how the required ignition timing Acal is set by the ignition timing control device of the present embodiment.
It should be noted that FIG. 7A shows the transition of the count value of the thinning-out counter, and FIG. 7B shows the transition of the required ignition timing Acal.

When the knocking intensity is smaller than or equal to a small knock or when the knocking frequency is small, based on the transition of the counter value of the knock counter shown in FIG.
As shown in (b), the reflection of the knock retard amount AKNK to the basic ignition timing ABSE is thinned out every other ignition (before the timing t1 in FIG. 7).

Thereafter, when a large knock occurs and the knock frequency increases (timing t1 in FIG. 7),
As shown in (b), thereafter, the thinning-out is prohibited until the knocking intensity becomes smaller than or equal to the small knocking or the knocking frequency becomes small (see FIG. 7).
Middle timings t1 to t2). That is, in this period, the knock retard amount AKNK is reflected in the required ignition timing Acal for all ignitions.

After that, when the knocking intensity becomes smaller than or equal to the small knocking or the knocking frequency becomes small, the thinning-out based on the count value of the knocking counter is restarted (timing t2 in FIG. 7).

As described above, according to this embodiment, the effects described below can be obtained. (1) When setting the required ignition timing Acal, the reflection of the knock retardation amount AKNK to the basic ignition timing ABSE is thinned out every other ignition. Therefore, in all ignitions, the knock retard amount AKNK is set to the required ignition timing Acal.
A knocking suppression effect that is almost the same as the case of reflecting the above is obtained, and the required ignition timing Acal in the ignition in which the reflection of the same knock delay amount AKNK is thinned is on the advance side (in FIG. The decrease in engine torque is suppressed by the amount shown. Therefore, it becomes possible to more easily achieve both suppression of knocking occurrence and suppression of unnecessary reduction in engine torque.

(2) The delay of the knock delay amount AKNK is prohibited from being skipped when a large knock occurs and the knock frequency is high. At this time, the knock retard amount AKNK is reflected in the required ignition timing Acal for all ignitions, so that knocking can be suppressed more quickly.

The above embodiment may be modified and implemented as follows. Further, in the above-described embodiment, the knock delay amount AKNK
So that the amount of retard angle reflected in the basic ignition timing ABSE is different between the period in which the thinning is reflected and the other period, the knock retard amount AKNK in the period in which the thinning is prohibited and the other period. It is also possible to correct at least one of the knock delay amount AKNK of. With such a configuration, it is possible to separately set the retardation amount reflected in the basic ignition timing ABSE as an amount suitable for each period between the period in which the thinning is prohibited and the other period. As a result, the degree of freedom in setting the required ignition timing Acal can be increased, and it is possible to achieve a more suitable balance between suppression of knocking occurrence and suppression of unnecessary reduction in engine torque.

In the above embodiment, the knock delay amount AK
The thinning of NK is prohibited when a large knock occurs and the knock frequency is high. Alternatively, the thinning-out may be prohibited when the knock frequency is high. Further, if the occurrence of knocking can be appropriately suppressed, the prohibition of thinning may be omitted.

In the above embodiment, the basic ignition timing AB
Although SE is calculated based on the engine speed NE and the intake air pressure PM, the present invention is not limited to this. In short, if the time when the engine torque becomes maximum is calculated without considering the knocking occurrence situation, the calculation mode can be arbitrarily changed.

The manner of calculating the knock delay amount AKNK is not limited to the manner of calculation according to the above embodiment. The point is that if the amount of retardation that is learned according to the knocking occurrence state and that the amount of retardation that can appropriately suppress the occurrence of knocking is calculated, the calculation mode can be arbitrarily changed. it can.

In the above embodiment, the basic ignition timing AB
Although the reflection of the knock retard amount AKNK to the SE is thinned out every other ignition, the present invention is not limited to this. In short, if the occurrence of knocking can be appropriately suppressed, the interval for thinning the reflection of the knock retardation amount AKNK may be appropriately changed, for example, every two ignitions, every three ignitions, or the like. Further, the thinning interval does not necessarily have to be set every fixed number of ignitions, and the number may be changed by a thinning control cycle.

In the above embodiment, only one cylinder is referred to, but when the ignition timing control device according to the present invention is applied to an internal combustion engine having a plurality of cylinders, a predetermined number of ignitions is performed for each cylinder. Knock retardation amount for each AKNK
It suffices that the thinning out is reflected. With such a configuration, it is possible to achieve well-balanced suppression of knocking occurrence in all of the plurality of cylinders.

Further, in this case, the variation of the engine torque can be suppressed as much as possible by thinning out the reflection of the knock retardation amount AKNK for every predetermined number of ignitions in the ignition order of each cylinder. Note that instead of the thinning for each predetermined number of times of ignition, the interval according to the thinning for the ignition order of each cylinder is set so that the variation is small, and the effect similar to the above effect can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an embodiment of an ignition timing control device for an internal combustion engine of the present invention.

FIG. 2 is a graph showing the relationship between the knock signal and the intensity of vibration of the internal combustion engine.

FIG. 3 is a graph showing changes in the peak value of the fluctuation speed of the pressure in the combustion chamber.

FIG. 4 is a flowchart showing a processing procedure for setting a required ignition timing.

FIG. 5 is a flowchart showing a processing procedure for setting a required ignition timing.

FIG. 6 is a flowchart showing a processing procedure when thinning the reflection of the retard amount.

FIG. 7 is a timing chart showing an example of a setting mode of required ignition timing.

[Explanation of symbols]

10 ... Internal combustion engine, 11 ... Intake passage, 12 ... Combustion chamber, 13
... crankshaft, 14 ... surge tank, 15 ... camshaft, 16 ... spark plug, 17 ... ignition coil, 18
... igniter, 21 ... knock sensor, 22 ... rotation speed sensor, 23 ... intake pressure sensor, 24 ... cam angle sensor, 30
… Electronic control unit.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kenji Kasashima             1 Toyota Town, Toyota City, Aichi Prefecture Toyota Auto             Car Co., Ltd. F-term (reference) 3G022 DA01 EA02 FA00 FA05 GA01                       GA05 GA07 GA13                 3G084 BA17 DA38 EA11 EB17 FA11                       FA25 FA33

Claims (5)

[Claims] 1. A basic ignition timing is calculated on the basis of the operating state of an internal combustion engine, and a retard angle amount is learned in accordance with the occurrence state of the engine so as to suppress the occurrence of knocking, and the basic ignition timing is set to the basic ignition timing. In an ignition timing control device for an internal combustion engine that controls the engine ignition timing while reflecting the learned retard angle amount, a thinning control that thins out the reflection of the learned retard angle amount to the basic ignition timing every predetermined ignition times. An ignition timing control device for an internal combustion engine, comprising: means. 2. The ignition timing control device for an internal combustion engine according to claim 1, wherein a knocking occurrence frequency of the engine is obtained, and when the obtained knocking occurrence frequency is equal to or higher than a predetermined frequency, the thinning-out control means performs thinning-out. An ignition timing control device for an internal combustion engine, further comprising thinning-out control prohibiting means for prohibiting control. 3. The ignition timing control device for an internal combustion engine according to claim 1, wherein a knocking strength and a knocking occurrence frequency of the engine are respectively obtained, and the knocking strength and the knocking occurrence frequency thus obtained are both predetermined or more. An ignition timing control device for an internal combustion engine, further comprising a thinning control inhibiting means for inhibiting the thinning control by the thinning control means. 4. The ignition timing control device for an internal combustion engine according to claim 2 or 3, wherein the learned retard angle amount is in a period in which the thinning-out control is prohibited by the thinning-out control prohibiting means and in other periods. An ignition timing control device for an internal combustion engine, further comprising: a correcting unit that corrects at least one of a retard amount during a period in which the thinning control is prohibited and a retard amount during another period so as to have different values. 5. The internal combustion engine comprises a plurality of cylinders,
The ignition timing control device for an internal combustion engine according to claim 1, wherein the thinning-out control means executes thinning-out control for each of the predetermined ignition times for each of the cylinders.