JP4677897B2 - Ignition timing control device for internal combustion engine - Google Patents

Description

  The present invention relates to an ignition timing control device for an internal combustion engine, and more particularly, to an ignition timing control device that controls an ignition timing by predicting an ignition timing at which knocking occurs.

  In the ignition timing control of an internal combustion engine, the ignition timing is advanced to the limit while being close to MBT while preventing knocking. The trace knock ignition timing, which is the limit ignition timing at which knock occurs, depends on operating conditions such as intake air temperature, engine temperature, engine speed, and load. For this reason, conventionally, the ignition timing control is performed using a map obtained by obtaining the trace knock ignition timing for each operating condition by experiments or the like.

However, the creation of a map requires adaptation work that requires enormous man-hours. For accurate ignition timing control, many parameters indicating operating conditions are required. However, as the number of parameters increases, the necessary map data becomes enormous and the number of man-hours required for adaptation work increases. Regarding such a problem, Patent Document 1 estimates the in-cylinder pressure and the unburned gas temperature at the reference crank angle after the compression top dead center based on the operating conditions of the internal combustion engine, and the occurrence of knocking occurs from the estimation result. A technique for calculating an index value for determining ease is proposed. Specifically, in this prior art, the self-ignition time of the elementary reaction is calculated as a knock index value. Then, the retard amount from the MBT is determined based on the calculated self-ignition time, and the ignition timing retarded from the MBT by the retard amount is obtained as the trace knock ignition timing.
JP 2004-245173 A JP 2005-36754 A

  By the way, according to experiments, it has been confirmed that there is a certain relationship between the maximum value of the in-cylinder pressure and the crank angle at which knocking occurs. The inventor of the present application pays attention to this relationship, and has devised a method for accurately predicting the trace knock ignition timing by a method different from the above-described prior art, without requiring enormous map data.

  That is, the present invention provides an ignition timing control device for an internal combustion engine that accurately predicts a trace knock ignition timing without requiring enormous map data and can perform ignition timing control based on the prediction. With the goal.

In order to achieve the above object, a first invention provides an ignition timing control device for an internal combustion engine.
Information acquisition means for acquiring information on operating conditions of the internal combustion engine;
Storage means for storing the relationship between the maximum value of the in-cylinder pressure and the crank angle at which knocking occurs for each operating condition;
Predicting means for predicting the relationship between the ignition timing and the in-cylinder pressure maximum value based on operating conditions;
Predicting means for predicting the crank angle at which the combustion ratio of the fuel in the cylinder becomes a predetermined value based on the operating conditions;
The relationship between the maximum in-cylinder pressure value and the knocking crank angle under the current operating conditions, the relationship between the ignition timing predicted under the current operating conditions and the maximum in-cylinder pressure value, and under the current operating conditions Calculation means for calculating an ignition timing at which the combustion ratio at the time of knock occurrence is a predetermined value under the current operating conditions from a crank angle at which the combustion ratio is a predetermined value;
Control means for controlling the ignition timing based on the calculation result;
It is characterized by having.

The second invention is the first invention, wherein
Knock signal detecting means for detecting a knock signal generated in the internal combustion engine;
The in-cylinder pressure maximum value stored in the storage means and the occurrence of knock based on the crank angle when the knock signal is detected and the maximum in-cylinder pressure value predicted from the set ignition timing and operating conditions at that time Correction means for correcting the relationship with the crank angle;
Is further provided.

The third invention is the first invention, wherein
In-cylinder pressure measuring means for measuring in-cylinder pressure;
Knock detection means for detecting the occurrence of knock from a change in in-cylinder pressure;
Based on the crank angle when the occurrence of knocking is detected and the in-cylinder pressure maximum value measured in the cycle in which the knock has occurred, the in-cylinder pressure maximum value and the knocking crank angle stored in the storage means Correction means for correcting the relationship between
Is further provided.

  In the first invention, the relationship between the ignition timing and the in-cylinder pressure maximum value and the crank angle at which the combustion ratio of the in-cylinder fuel becomes a predetermined value are predicted from the current operating conditions of the internal combustion engine. Based on these prediction results and the relationship between the pre-stored maximum in-cylinder pressure value and the knock generation crank angle, the ignition timing at which the combustion ratio at the time of knock occurrence becomes a predetermined value under the current operating conditions is determined. Calculated. The size of the knock and the presence or absence of occurrence depend on the combustion rate. Therefore, the trace knock ignition timing can be obtained by the above calculation by setting the predetermined value to a combustion ratio value at which a weak knock occurs. That is, according to the first aspect, the trace knock ignition timing under the current operating condition can be accurately predicted, and the ignition timing can be controlled based on the predicted trace knock ignition timing. Moreover, the data that is required in advance is only data relating to the relationship between the maximum value of the in-cylinder pressure for each operating condition and the crank angle at which knocking occurs, and enormous map data is not required.

  Further, according to the second invention, based on the crank angle when the knock signal is actually detected and the maximum in-cylinder pressure predicted from the set ignition timing and operating conditions at that time, the maximum in-cylinder pressure is obtained. The relationship between the value and the knocking crank angle can be learned. This makes it possible to accurately predict the trace knock ignition timing even when the knock characteristics of the internal combustion engine change due to factors that cannot be taken into account by models or mathematical formulas, such as individual differences or aging of the internal combustion engine.

  According to the third aspect of the invention, the relationship between the in-cylinder pressure maximum value and the knock generation crank angle can be learned based on the actually measured in-cylinder pressure maximum value and the knock generation crank angle. This makes it possible to accurately predict the trace knock ignition timing even when the knock characteristics of the internal combustion engine change due to factors that cannot be taken into account by models or mathematical formulas, such as individual differences or aging of the internal combustion engine.

Embodiment 1 FIG.
Hereinafter, the first embodiment of the present invention will be described with reference to FIGS.

  In Embodiment 1 of the present invention, an ignition timing control device is realized as a function of an ECU (Electronic Control Unit) that comprehensively controls an internal combustion engine (hereinafter, engine). The ECU is connected to a plurality of sensors (information acquisition means) for acquiring various information related to the engine operating conditions, but the description thereof is omitted here.

  In the ignition timing control by the ECU, the trace knock ignition timing is determined based on the operating condition of the engine, and a driver for operating the spark plug is driven based on the determined trace knock ignition timing. The ECU determines the trace knock ignition timing by the routine shown in the flowchart of FIG. The routine shown in FIG. 1 is executed every cycle.

  In the first step S100 of the routine shown in FIG. 1, information on the current engine operating conditions is acquired based on signals from various sensors connected to the ECU. The operating condition information includes information such as engine speed, engine load, valve timing, air-fuel ratio, intake air temperature, fuel octane number, and the like.

  In the next step S102, the relationship between the ignition timing and the maximum value Pmax of the in-cylinder pressure is predicted using an engine model. For example, a Wiebe model can be used as the engine model. The value of each parameter of the Wiebe model is preset according to the operating conditions and stored in the map. In step S102, a parameter value corresponding to the operating condition acquired in step S100 is read from the map, and calculation using the Wiebe model is performed using the parameter value. FIG. 2 is a diagram illustrating an example of the calculation result of step S102. As shown in this figure, the calculation of the in-cylinder pressure maximum value Pmax by the Wiebe model is performed for a plurality of preset representative ignition timings.

  In the next step S104, calculation is performed using the map shown in FIG. The map shown in FIG. 3 is a map (hereinafter referred to as a Pmax-CAkc map) showing the correspondence between the in-cylinder pressure maximum value Pmax and the knock generation crank angle CAkc. This Pmax-CAkc map is prepared for each engine load.

  The Pmax-CAkc map is created from data obtained during engine test operation. When the engine is operated, the in-cylinder pressure changes with respect to the crank angle as shown in FIG. 4, and the in-cylinder pressure maximum value Pmax and the knock generation crank angle CAkc are determined for each cycle. The in-cylinder pressure maximum value Pmax may be a value including the amplitude of knock vibration as shown in the figure, or may be a value excluding the amplitude of knock vibration through a filter. Since the amplitude of the knock vibration is very small compared to the absolute value of the in-cylinder pressure, the influence of the amplitude of the knock vibration on the in-cylinder pressure maximum value Pmax is within an error range and can be ignored. The Pmax-CAkc map is obtained by obtaining the in-cylinder pressure maximum value Pmax and the knock generation crank angle CAkc for each cycle and plotting them on a graph prepared for each engine load. As shown in the Pmax-CAkc map, the in-cylinder pressure maximum value Pmax and the knock generation crank angle CAkc are in a proportional relationship.

  In step S104, first, a Pmax-CAkc map corresponding to the engine load is selected from the operating conditions acquired in step S100. Then, the in-cylinder pressure maximum value Pmax for each representative ignition timing calculated in step S102 is collated with the selected Pmax-CAkc map, and the knock generation crank angle CAkc corresponding to each in-cylinder pressure maximum value Pmax is calculated. .

  In the next step S106, the combustion ratio Bk at each knock generation crank angle CAkc calculated in step S104 is calculated. The combustion ratio is defined as the total heat generation up to the crank angle with respect to the total heat generation of the supplied fuel. The relationship between the crank angle and the combustion ratio can be obtained by using an engine model (heat generation model) such as a Wiebe model. The value of each parameter of the Wiebe model is preset according to the operating conditions and stored in the map. In step S106, first, a parameter value corresponding to the operating condition acquired in step S100 is read from the map, and calculation using the Wiebe model is performed using the parameter value. FIG. 5 is a diagram showing the relationship between the crank angle and the combustion ratio obtained by calculation. By using this relationship, the combustion ratio Bk at each knock generation crank angle CAkc can be calculated.

  In the next step S108, the ignition timing Sk at which the combustion ratio Bk at the time of knock occurrence becomes the predetermined value Bko is calculated using the calculation results in steps S102 to S106. Specifically, in-cylinder pressure maximum value Pmax at each representative ignition timing calculated in step S102, knock generation crank angle CAkc corresponding to each in-cylinder pressure maximum value Pmax calculated in step S102, and in step S106 From the calculated combustion ratio Bk at each knock generation crank angle CAkc, a knock generation combustion ratio Bk corresponding to each representative ignition timing is calculated. As shown in FIG. 6, a certain relationship is found between the representative ignition timing and the combustion rate Bk at the time of knock occurrence, that is, a relationship in which the combustion rate Bk at the time of knock occurrence decreases as the ignition timing advances. Therefore, by performing interpolation calculation based on this relationship, as shown in the figure, it is possible to calculate the ignition timing Sk at which the combustion rate Bk at the time of knock occurrence becomes the predetermined value Bko.

  The size of the knock and the presence or absence of the knock depend on the combustion rate. Specifically, as the combustion rate increases, the unburned fuel in the combustion chamber decreases. Therefore, when the combustion rate is too high, there is no more fuel to be burned, so rapid combustion does not occur and knock does not occur. That is, the combustion ratio has an upper limit value at which knocking can occur. The predetermined value Bko is set to a value near this upper limit value (for example, about 90%). Thus, the ignition timing Sk obtained by the calculation in step S108 means the limit ignition timing at which knocking occurs under the current operating conditions, that is, the trace knock ignition timing. In the next step S110, the ignition timing Sk calculated in step S108 is determined as the trace knock ignition timing.

  Note that if the engine operating conditions change, the upper limit value of the combustion rate at which knocking can occur also changes. Therefore, it is preferable to obtain the upper limit value of the combustion rate at which knocking may occur by experiment or calculation for each engine operating condition, and to set a predetermined value Bko corresponding to the upper limit value for each engine operating condition.

  According to the routine described above, it is possible to accurately predict the trace knock ignition timing under the current operating conditions, and to control the ignition timing based on the accurate trace knock ignition timing. Moreover, the data required in advance is only the map data of the Pmax-CAkc map, and a huge amount of map data is not required.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to FIGS.

  The ignition timing control apparatus as the second embodiment of the present invention can be realized by causing the ECU to execute a routine shown in the flowchart of FIG. 7 instead of the routine shown in the flowchart of FIG. In the routine shown in FIG. 7, the same step numbers are assigned to the processes having the same contents as those in the routine shown in FIG. In the following, redundant description of the processing already described in the first embodiment will be omitted, and processing unique to this embodiment will be described.

  In the first step S100-2 of the routine shown in FIG. 7, information on the current engine operating conditions is acquired. The operating condition information acquired in the present embodiment includes the crank angle CAkcs at which knocking actually occurred in the previous cycle, in addition to the various information acquired in the first embodiment. A knock sensor is attached to the cylinder block of the engine according to the present embodiment. The knock sensor detects knock vibration (knock signal) transmitted from the combustion chamber to the cylinder block. The ECU receives a signal (knock detection signal) output from the knock sensor when the knock signal is detected, and acquires the crank angle at that time as a knock generation crank angle CAkcs.

  In the routine shown in FIG. 7, the determination in step S200 is performed after the processing in step S102. In step S200, it is determined whether a knock (trace knock) has actually occurred from the strength and frequency of the knock detected by the knock sensor. When knocking occurs, the knocking crank angle CAkcs is included in the driving condition information acquired in step S100-2. When knocking does not occur, the knocking crank is included in the driving condition information. Corner CAkcs are not included. As a result of the determination, if knocking has not occurred, the process proceeds to step S104, and the processing from step S104 to step S110 is executed as in the first embodiment.

  If knocking has occurred as a result of the determination in step S200, the process in step S202 is executed. In step S202, the map data of the Pmax-CAkc map is corrected using the knock generation crank angle CAkcs acquired in step S100-2. FIG. 8 is a diagram illustrating an example of a correction method for the Pmax-CAkc map. As indicated by a solid line in the figure, the relationship between Pmax and CAkc defined in the Pmax-CAkc map is represented by a single straight line. In step S202, first, points having the coordinates of the knocking crank angle CAkcs and the in-cylinder pressure maximum value Pmaxc are plotted on this graph. The in-cylinder pressure maximum value Pmaxc is the in-cylinder pressure maximum value predicted using the engine model described above under the current ignition timing. Then, a straight line indicating the relationship between Pmax and CAkc is translated so as to pass through the plotted points (CAkcs, Pmaxc) as indicated by a broken line in the figure. The relationship between the in-cylinder pressure maximum value Pmax and the knock generation crank angle CAkc indicated by the straight line (broken line) after translation is updated as a corrected Pmax-CAkc map. At this time, as shown in FIG. 8, the offset amount in the Y-axis (Pmax) direction is acquired as the correction amount Cf of the Pmax-CAkc map.

  Note that the correction of the Pmax-CAkc map by the above-described method is performed for the Pmax-CAkc map corresponding to the engine load acquired in step S100-2. However, other Pmax-CAkc maps prepared for each engine load can be corrected. In that case, the straight line indicating the relationship between Pmax and CAkc may be offset by the correction amount Cf for the other Pmax-CAkc maps. The above correction method is merely an example, and the map data of the Pmax-CAkc map may be corrected by other methods.

  In the next step S204, it is determined whether or not the correction amount Cf exceeds the reference value Cb. When the correction amount Cf is within the reference value Cb, the process proceeds to step S104, and the in-cylinder pressure maximum value Pmax for each representative ignition timing calculated in step S102 is collated with the corrected Pmax-CAkc map. A knock generation crank angle CAkc corresponding to the in-cylinder pressure maximum value Pmax is calculated. Thereafter, similarly to the first embodiment, the processing from step S106 to step S110 is executed.

  If the correction amount Cf exceeds the reference value Cb as a result of the determination in step S204, that is, if the correction of the Pmax-CAkc map is excessive, there is some abnormality in the sensor related to ignition timing control such as a knock sensor. Is determined (step S206). In this case, a signal notifying the abnormality of the sensor is output and the control by this routine is finished.

  According to the routine described above, the map of the Pmax-CAkc map is based on the crank angle CAkc when knocking actually occurs and the in-cylinder pressure maximum value Pmaxc predicted from the set ignition timing and operating conditions at that time. Data can be learned. This makes it possible to accurately predict the trace knock ignition timing even when the engine knock characteristics change due to factors that cannot be taken into account by models or mathematical formulas, such as individual engine differences or aging.

  Further, according to the above routine, since the reference value Cb that defines the normal correction range is provided in the correction amount Cf of the map data, an abnormality of a sensor such as a knock sensor is prevented while preventing erroneous correction of the map data. It can also be discovered early.

Embodiment 3 FIG.
Next, Embodiment 3 of the present invention will be described with reference to FIG. 9 and FIG.

  The ignition timing control apparatus according to the third embodiment of the present invention can be realized by causing the ECU to execute a routine shown in the flowchart of FIG. 9 instead of the routine shown in the flowchart of FIG. In the routine shown in FIG. 9, processes having the same contents as those in the routine shown in FIG. In the following, redundant description of the processing already described in the first embodiment will be omitted, and processing unique to this embodiment will be described.

  In the first step S100-3 of the routine shown in FIG. 9, information on the current engine operating conditions is acquired. The operating condition information acquired in the present embodiment includes the actual in-cylinder pressure maximum value Pmaxs in the previous cycle and the crank angle CAkcs at which the actual knocking occurred in addition to the various information acquired in the first embodiment. . An in-cylinder pressure sensor is attached to the cylinder head of the engine according to the present embodiment. The in-cylinder pressure sensor outputs a signal (in-cylinder pressure signal) corresponding to the pressure in the combustion chamber. The ECU measures the in-cylinder pressure maximum value Pmaxs from the in-cylinder pressure signal, detects the occurrence of knock from the fluctuation of the in-cylinder pressure signal, and acquires the crank angle at that time as the knock generation crank angle CAkcs.

  In the routine shown in FIG. 9, the determination in step S300 is subsequently performed. In step S300, it is determined whether or not there is a knock generation cycle in which knock (trace knock) has actually occurred from the fluctuation of the in-cylinder pressure signal. When knocking occurs, the knocking crank angle CAkcs is included in the driving condition information acquired in step S100-3. When knocking does not occur, the knocking crank is included in the driving condition information. Corner CAkcs are not included. As a result of the determination, if knocking has not occurred, the process proceeds to step S102.

  In step S102, as in the first embodiment, the in-cylinder pressure maximum value Pmax at each representative ignition timing is predicted using the engine model. At that time, based on the actual in-cylinder pressure maximum value Pmaxs acquired in step S100-3 and the current ignition timing, the in-cylinder pressure maximum value Pmax at each representative ignition timing is corrected. Thereafter, similarly to the first embodiment, the processing from step S104 to step S110 is executed.

  If knocking has occurred as a result of the determination in step S300, the process in step S302 is executed. In step S202, the map data of the Pmax-CAkc map is corrected using the in-cylinder pressure maximum value Pmaxs and the knock generation crank angle CAkcs acquired in step S100-3. FIG. 10 is a diagram illustrating an example of a correction method for the Pmax-CAkc map. As indicated by a solid line in the figure, the relationship between Pmax and CAkc defined in the Pmax-CAkc map is represented by a single straight line. In step S302, first, points having the coordinates of the knocking crank angle CAkcs and the in-cylinder pressure maximum value Pmaxs are plotted on this graph. Then, a straight line indicating the relationship between Pmax and CAkc is translated so as to pass through the plotted points (CAkcs, Pmaxs) as indicated by a broken line in the drawing. The relationship between the in-cylinder pressure maximum value Pmax and the knock generation crank angle CAkc indicated by the straight line (broken line) after translation is updated as a corrected Pmax-CAkc map. At this time, as shown in FIG. 10, the offset amount in the Y-axis (Pmax) direction is acquired as the correction amount Cf of the Pmax-CAkc map.

  The correction of the Pmax-CAkc map by the above-described method is performed on the Pmax-CAkc map corresponding to the engine load acquired in step S100-3. However, other Pmax-CAkc maps prepared for each engine load can be corrected. In that case, the straight line indicating the relationship between Pmax and CAkc may be offset by the correction amount Cf for the other Pmax-CAkc maps. The above correction method is merely an example, and the map data of the Pmax-CAkc map may be corrected by other methods.

  In the next step S304, it is determined whether or not the correction amount Cf exceeds the reference value Cb. If the correction amount Cf is within the reference value Cb, the process proceeds to step S102. In step S102, as described above, the in-cylinder pressure maximum value Pmax at each representative ignition timing is predicted using the engine model. At that time, based on the actual in-cylinder pressure maximum value Pmaxs and the current ignition timing, Correction of the in-cylinder pressure maximum value Pmax at the representative ignition timing is performed. In the next step S104, the in-cylinder pressure maximum value Pmax for each representative ignition timing calculated in step S102 is collated with the Pmax-CAkc map corrected in step S302 and corresponds to each in-cylinder pressure maximum value Pmax. Knock generation crank angle CAkc is calculated. Thereafter, similarly to the first embodiment, the processing from step S106 to step S110 is executed.

  As a result of the determination in step S304, if the correction amount Cf exceeds the reference value Cb, that is, if the correction of the Pmax-CAkc map is excessive, there is some abnormality in the sensor related to ignition timing control such as the in-cylinder pressure sensor. It is determined that there is (step S306). In this case, a signal notifying the abnormality of the sensor is output and the control by this routine is finished.

  According to the routine described above, the map data of the Pmax-CAkc map can be learned based on the actually measured in-cylinder pressure maximum value Pmaxs and the crank angle CAkc when knocking actually occurs. This makes it possible to accurately predict the trace knock ignition timing even when the engine knock characteristics change due to factors that cannot be taken into account by models or mathematical formulas, such as individual engine differences or aging.

  Further, according to the above routine, it is possible to detect the occurrence of knock without using a knock sensor that easily picks up noise, and therefore it is possible to accurately predict the trace knock ignition timing. Further, since map data is corrected using the actually measured in-cylinder pressure maximum value Pmaxs, the map data is corrected by using the estimated in-cylinder pressure maximum value Pmaxc, and the map data is corrected. Since the error can be eliminated, a more accurate trace knock ignition timing can be predicted.

  Further, according to the above routine, since the reference value Cb that defines the normal correction range is provided in the correction amount Cf of the map data as in the second embodiment, the cylinder data can be corrected while preventing the map data from being erroneously corrected. It is also possible to detect an abnormality in a sensor such as an internal pressure sensor at an early stage.

Others.
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, the following modifications may be made.

  In step S104 of each embodiment, a Pmax-CAkc map is prepared for each engine load. However, in order to further improve the accuracy of map data, a Pmax-CAkc map is prepared for each engine load and each engine speed. May be. Further, since the in-cylinder pressure maximum value Pmax and the knock generation crank angle CAkc are in a proportional relationship, an approximate expression (primary expression of Pmax-CAkc) may be used instead of the map. Also in this case, a formula of Pmax-CAkc is prepared for each engine load, more preferably for each engine load and for each engine speed. When the approximate expression is used, the memory of the ECU can be saved.

  In step S106 of each embodiment, instead of calculating the combustion rate Bk at each knock generation crank angle CAkc, the crank angle CAbk at which the combustion rate becomes the predetermined value Bko may be calculated. The crank angle CAbk can be calculated every time using an engine model such as a Wiebe model, or can be read from a map created in advance for each operating condition. In this case, in the next step S108, the ignition timing corresponding to the crank angle CAbk is calculated by interpolation from the relationship between each representative ignition timing obtained from the calculation results of steps S102 and S104 and the knocking crank angle CAkc. Thereby, the ignition timing Sk at which the combustion rate Bk at the time of knock occurrence becomes the predetermined value Bko, that is, the trace knock ignition timing can be obtained.

It is a flowchart of the routine for determination of the trace knock ignition timing performed in Embodiment 1 of this invention. It is a figure which shows the relationship between each representative ignition timing obtained by calculation using a model, and the cylinder pressure maximum value Pmax. It is a figure which shows the correspondence of the cylinder pressure maximum value Pmax and knock generation | occurrence | production crank angle CAkc in a Pmax-CAkc map. It is a figure which shows the change of the cylinder pressure with respect to a crank angle. It is a figure which shows the relationship between the crank angle obtained by calculation using a model, and a combustion rate. It is a figure which shows the relationship between the representative ignition timing and the combustion rate Bk at the time of knock occurrence. It is a flowchart of the routine for determination of the trace knock ignition timing performed in Embodiment 2 of this invention. It is a figure shown about an example of the correction method of the Pmax-CAkc map concerning Embodiment 2 of this invention. It is a flowchart of the routine for determination of the trace knock ignition timing performed in Embodiment 3 of this invention. It is a figure shown about an example of the correction method of the Pmax-CAkc map concerning Embodiment 3 of this invention.

Claims (3)

Information acquisition means for acquiring information relating to operating conditions of the internal combustion engine;
Storage means for storing the relationship between the maximum value of the in-cylinder pressure and the crank angle at which knocking occurs for each operating condition;
A predicting means for predicting a relationship between the ignition timing and the in-cylinder pressure maximum value based on operating conditions;
A predicting means for predicting a crank angle at which the combustion ratio of the fuel in the cylinder reaches a predetermined value based on operating conditions;
Relationship between maximum in-cylinder pressure value and knocking crank angle under current operating conditions, relationship between ignition timing and in-cylinder pressure maximum value predicted under current operating conditions, and under current operating conditions Calculation means for calculating an ignition timing at which the combustion ratio at the time of knock occurrence becomes a predetermined value under a current operating condition from a crank angle at which the combustion ratio reaches a predetermined value;
Control means for controlling the ignition timing based on the calculation result;
An ignition timing control device for an internal combustion engine, comprising: Knock signal detecting means for detecting a knock signal generated in the internal combustion engine;
The in-cylinder pressure maximum value stored in the storage means and the occurrence of knock based on the crank angle when the knock signal is detected and the maximum in-cylinder pressure value predicted from the set ignition timing and operating conditions at that time Correction means for correcting the relationship with the crank angle;
The ignition timing control device for an internal combustion engine according to claim 1, further comprising: In-cylinder pressure measuring means for measuring in-cylinder pressure;
Knock detection means for detecting the occurrence of knock from a change in in-cylinder pressure;
Based on the crank angle when the occurrence of knocking is detected and the in-cylinder pressure maximum value measured in the cycle in which the knocking has occurred, the in-cylinder pressure maximum value and the knocking crank angle stored in the storage means Correction means for correcting the relationship between
The ignition timing control device for an internal combustion engine according to claim 1, further comprising:

Images