JP5098980B2 - 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.

In a vehicle in which an internal combustion engine is mounted as a drive source, so-called ignition timing control is performed in which the ignition timing is controlled according to the operating state of the internal combustion engine.
In this ignition timing control, basically, a control target value for the ignition timing is set based on the operating state of the internal combustion engine. This control target value is corrected by a feedback correction term that is updated according to whether knocking has occurred. The feedback correction term is changed by a predetermined delay update amount when knocking occurs to correct the ignition timing, and is changed by a predetermined advance update amount when knocking does not occur. Correct the ignition timing. The control target value is corrected by a learning value that is updated based on the feedback correction term. As this learning value, for example, a value obtained by subjecting the feedback correction term to a gradual change process is calculated.

  Conventionally, as such a learning value, a first learning value for compensating for a change in ignition timing due to a change with time of the internal combustion engine (for example, deposit adhesion in the engine combustion chamber) and other factors (for example, a change in fuel properties) ) Has been proposed in which two learning values, ie, a second learning value for compensating for the change in ignition timing due to () are set (see, for example, Patent Document 1).

In the device described in Patent Document 1, learning of the first learning value is permitted in the first engine operation region where the influence on the ignition timing due to the deposit adhesion in the engine combustion chamber is large, but the influence is small. In the second engine operation region, learning of the first learning value is prohibited. As a result, a value suitable for the change in ignition timing due to deposit adhesion is learned as the first learning value, and a value suitable for the change in ignition timing due to a factor other than deposit adhesion is learned as the second learning value. The ignition timing is controlled according to the cause of knocking.
JP 2005-147112 A (paragraphs [0174], [0178])

  By the way, if the operating environment of the internal combustion engine (for example, the temperature and humidity of the intake air) and the properties of the fuel supplied to the internal combustion engine (for example, the octane number) change, the occurrence of knocking will change, and feedback is accompanied accordingly. The correction term also changes. Therefore, if the learning permission and the learning prohibition of the first learning value are switched according to the operation region of the internal combustion engine as in the device described in Patent Document 1, when the above-described operating environment and fuel properties change. The following inconvenience occurs.

  That is, when the internal combustion engine is operated in the first engine operation region immediately after the change of the operating environment and the fuel property, the ignition timing (specifically, the feedback correction term) is changed due to the change. This is reflected in the first learning value for compensating for the change in the ignition timing due to the change over time. This is not preferable because each learning value is a factor that obstructs the learning of the learning value to a value suitable for the compensation object.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an ignition timing control device for an internal combustion engine that can appropriately learn the engine ignition timing at the time of refueling.

Hereinafter, means for achieving the above-described object and its operation and effects will be described.
According to the first aspect of the present invention, the basic value set based on the operating state of the internal combustion engine is corrected by the feedback correction term updated in accordance with the presence / absence of knocking and the learning value updated based on the feedback correction term. The control target value of the ignition timing is set, and the first learning value that compensates for the change in the ignition timing due to the change of the internal combustion engine over time as the learning value and the change in the ignition timing due to other factors are compensated. In the internal combustion engine ignition timing control apparatus that learns the learning value of 2 separately, the first learning value and the second learning value in the first engine operating region in which the change over time of the internal combustion engine has a great influence on the ignition timing. The basic value is corrected by the learning value of the control value to set the control target value, and in the second engine operation region where the influence is small, the basic value is corrected only by the second learning value. Setting means for setting a control target value and only learning of the first learning value is permitted in the first engine operation region, and only learning of the second learning value is permitted in the second engine operation region. The learning amount so that the restriction degree of the learning amount per unit period of the first learning value is larger than the restriction degree of the learning amount per unit period of the second learning value. The gist of the present invention is to provide limiting means for limiting.

  When the operating environment of the internal combustion engine and the properties of the supplied fuel change greatly, the engine ignition timing changes rapidly accordingly. For this reason, it is desirable to set a value that changes rapidly in response to a sudden change in the ignition timing, as the second learning value that compensates for the change in the ignition timing due to changes in the operating environment and fuel properties. On the other hand, the change in the engine ignition timing accompanying the change with time of the internal combustion engine proceeds slowly over a long period. Therefore, the first learning value for compensating for the change in the ignition timing due to the change over time of the internal combustion engine may be set to a value that changes at a slow speed in accordance with the change in the ignition timing.

  According to the above configuration, since the degree of restriction of the learning amount of the first learning value learned in the first engine operation region where the influence on the ignition timing due to the change with time of the internal combustion engine is large is large, The value can be appropriately learned according to the change in the ignition timing that progresses slowly in accordance with the progress of the change over time of the internal combustion engine. Moreover, in the first engine operating region immediately after the operating environment and fuel properties have changed significantly, the ignition timing changes greatly at this time, but the amount of change reflected in the first learning value is kept small. Therefore, the amount of reflection that is erroneously reflected in the first learning value in the change in the ignition timing accompanying the change in the operating environment and the fuel property can be suppressed to a small amount. Furthermore, since the degree of restriction on the amount of update of the second learning value learned in the second engine operating region where the influence on the ignition timing due to changes over time of the internal combustion engine is small is small, the operating environment and fuel properties have changed significantly. In this case, the second learning value can appropriately learn the change in the ignition timing in accordance with the rapid change in the ignition timing accompanying the change.

  Thus, according to the above configuration, when the operating environment of the internal combustion engine and the properties of the supplied fuel change, the change in the ignition timing due to the change is suppressed from being reflected in the first learning value, and the same. The change can be quickly reflected in the second learning value, and the ignition timing can be appropriately learned.

  In addition, as described above, the configuration in which the degree of restriction on the learning amount per unit period of the first learning value is larger than the degree of restriction on the learning amount per unit period of the second learning value is according to claim 2 As described above, this can be realized by adopting a configuration in which the learning amount per unit period of the first learning value is limited and the learning amount per unit period of the second learning value is not limited.

  According to a third aspect of the present invention, in the ignition timing control device for an internal combustion engine according to the first or second aspect, the device includes a plurality of multiple engine engines in which the first engine operation region is divided according to the engine operation state. A first learning value is set for each of the multipoint learning areas, and the current engine operating state of the plurality of multipoint learning areas in the first engine operating area The gist of the present invention is to update the first learning value for a region including.

  The influence on the occurrence of knocking due to changes over time of the internal combustion engine (such as adhesion of deposits in the engine combustion chamber) may vary greatly for each fine operating region. In this case, if the control target value is set using the same value as the first learning value regardless of the engine operation region, the first learning value may be knocked depending on the change over time of the internal combustion engine depending on the engine operation region. It may be an inappropriate value for suppressing the occurrence of Specifically, the first learning value is a value that changes the ignition timing from the proper timing to the advance timing, so that the occurrence of knocking cannot be effectively suppressed, or the first learning value is appropriate for the ignition timing. Therefore, there is a risk that the output of the internal combustion engine may be reduced due to a value that is changed from the normal timing to the retarded timing.

  According to the above configuration, in the engine operation region where the variation in the influence on the occurrence of knocking due to the change with time of the internal combustion engine is large, the first learning value set for each multipoint learning region obtained by subdividing the region. Can be learned to appropriate values for suppressing the occurrence of knocking. Therefore, it is possible to suppress the occurrence of problems such as occurrence of knocking that cannot be effectively suppressed by learning an inappropriate value as the first learning value, or a decrease in the output of the internal combustion engine.

  As the unit period, a predetermined fixed time is adopted, or the same learning is performed in an apparatus in which both the first learning value and the second learning value are updated through a learning process executed every predetermined period. In addition to adopting the execution cycle of the process, a period during which the same learning value is continuously learned can be adopted as in claim 4.

  According to the fifth aspect of the present invention, a period from when the operation switch is operated to start the operation of the internal combustion engine to when the operation switch is operated to stop the operation can be adopted as the unit period.

  According to a sixth aspect of the present invention, in the internal combustion engine ignition timing control apparatus according to any one of the first to fifth aspects, the first learning value and the second learning value are both volatile memories. When the operation of connecting a storage battery to an electric circuit for supplying electric power to the internal combustion engine and its peripheral devices is performed, the apparatus learns the learning amount over a predetermined period thereafter. The gist of the present invention is to further include a restriction relaxation means for temporarily reducing the degree of restriction on.

  In the above configuration, once the connection between the electric circuit and the storage battery is released, both the first learning value and the second learning value that have been sequentially learned until then are lost, and thereafter the electric circuit When the battery and the storage battery are reconnected, it may take a long time until each learning value is learned and becomes a value suitable for the actual situation.

  According to the above configuration, when the operation of connecting the storage battery to the electric circuit is performed, the restriction on the learning amount in the learning is relaxed, so that the first learning value and the second learning value that have once disappeared Can be changed to a value suitable for the actual situation at an early stage.

  A seventh aspect of the present invention is the ignition timing control device for an internal combustion engine according to the sixth aspect, wherein the restriction relaxation means temporarily releases the restriction on the learning amount. To do.

According to the above configuration, the first learning value and the second learning value can be changed earlier to values that match the actual situation.
Note that the above-described configuration for limiting the learning amount per unit period of the learning value can be realized by a configuration in which an allowable limit amount that sets an allowable limit for the learning amount is set, as in claim 8. it can.

DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment in which an ignition timing control device for an internal combustion engine according to the present invention is embodied will be described.
FIG. 1 shows a schematic configuration of an internal combustion engine to which the ignition timing control device according to the present embodiment is applied.

  As shown in FIG. 1, air is sucked into the combustion chamber 11 of the internal combustion engine 10 through the intake passage 12 and fuel injected from the fuel injection valve 13 is supplied. The fuel stored in the fuel tank 14 is pumped to the fuel injection valve 13 by a fuel pump 15. When the air-fuel mixture composed of the intake air and the injected fuel is ignited by the spark plug 16, the air-fuel mixture burns, the piston 17 reciprocates, and the crankshaft 18 of the internal combustion engine 10 rotates. . The air-fuel mixture after combustion is sent as exhaust gas from the combustion chamber 11 of the internal combustion engine 10 to the exhaust passage 19.

  The ignition timing control device according to the present embodiment includes an electronic control device 30 that executes various controls for the operation of the internal combustion engine 10. The electronic control unit 30 includes a central processing unit (CPU) that executes various arithmetic processes related to various controls, a non-volatile memory (ROM) that stores programs and data necessary for the arithmetic operation, and the arithmetic results of the CPU. A volatile memory (RAM 30a) that is temporarily stored, an input / output port for inputting / outputting signals to / from the outside, and the like are provided.

  Various sensors are connected to the input port of the electronic control unit 30. As such sensors, for example, an accelerator sensor 31 for detecting the depression amount of the accelerator pedal 20 (accelerator depression amount AC), and an opening degree of the throttle valve 21 provided in the intake passage 12 (throttle opening degree TA) are detected. There are provided a throttle sensor 32 and a knock sensor 33 for detecting occurrence of knocking in the internal combustion engine 10. In addition, the air amount sensor 34 for detecting the amount of air passing through the intake passage 12 (passage air amount GA), the rotational speed (engine rotational speed NE) and the rotational angle (crank angle “° CA”) of the crankshaft 18. ) Is detected, and an operation switch 36 that is operated when the internal combustion engine 10 is started or stopped is also provided.

  The electronic control unit 30 grasps the operating state of the internal combustion engine 10 such as the engine rotational speed NE and the engine load KL based on output signals from various sensors. The engine load KL is calculated based on the intake air amount of the internal combustion engine 10 and the engine rotational speed NE obtained based on the accelerator depression amount AC, the throttle opening degree TA, and the passage air amount GA. The electronic control unit 30 outputs a command signal to various drive circuits connected to the output port in accordance with the operation state of the internal combustion engine 10 thus grasped. In this way, various controls such as ignition timing control of the internal combustion engine 10 are executed by the electronic control unit 30.

  The apparatus according to the present embodiment includes a storage battery 22, and this storage battery 22 is connected to an electric circuit (including the electronic control unit 30) for supplying electric power to the internal combustion engine 10 and its peripheral devices. In this device, even after the operation switch 36 is operated to stop the operation of the internal combustion engine 10, the power supply to the RAM 30a of the electronic control device 30 is maintained and the stored value is held. Yes.

Next, ignition timing control of the internal combustion engine 10 will be described with reference to FIG.
In the ignition timing control of the present embodiment, the ignition timing of the internal combustion engine 10 is controlled based on a control target value (specifically, the ignition timing command value ST) obtained from the operating state of the internal combustion engine 10 and the like. The smaller the timing command value ST is, the more the ignition timing of the internal combustion engine 10 is controlled to be retarded.

  As shown in FIG. 2, the ignition timing command value ST basically increases or decreases with respect to the knock limit ignition timing (BT-R) calculated based on the operating state of the internal combustion engine 10 depending on whether knocking occurs. The correction by the feedback correction term F and the correction by the basic learning value AG [i] updated based on the feedback correction term F are calculated.

  As knock limit ignition timing (BT-R), a value obtained by subtracting knock margin R from base ignition timing BT (solid line L1) is calculated. The base ignition timing BT is a value corresponding to the most advanced ignition timing at which knocking does not occur under standard environmental conditions, and is calculated based on the engine load KL and the engine speed NE. The knock margin R is a fixed value determined in advance by experiments or the like.

  The knock limit ignition timing (BT-R) calculated in this way is a value (broken line L2) obtained by retarding the base ignition timing BT by the knock margin R, in other words, under the environmental conditions where knocking is most likely to occur. This value represents the most advanced ignition timing in the ignition timing range that does not cause knocking. Examples of the environmental conditions include temperature, humidity, atmospheric pressure, engine cooling water temperature, and the like, and the likelihood of occurrence of knocking in the internal combustion engine 10 changes according to these conditions. In the present embodiment, knock limit ignition timing (BT-R) functions as a basic value.

  When it is determined that knocking has occurred based on the output signal of the knock sensor 33, the feedback correction term F is decreased by a predetermined delay update amount a to retard the ignition timing, while knocking occurs. When it is determined that the ignition timing has not been reached, the value is increased by the predetermined advance angle update amount b to advance the ignition timing. By this feedback correction term F, when knocking occurs, the ignition timing is immediately retarded to suppress the occurrence, and when knocking does not occur, the ignition timing is advanced to increase the engine output.

  The basic learning value AG [i] is a plurality (three in the present embodiment) of basic learning regions i [i = 1, 2] divided by the engine operating state (specifically, the engine load KL and the engine speed NE). , 3]. FIG. 3 shows the basic learning area i. In the example shown in FIG. 3, the basic learning area i [i = 1, 2, 3] divided into three according to the engine speed NE is set. Has been. When the ignition timing command value ST is calculated, the value of the basic learning region i corresponding to the engine speed NE at that time is used as the basic learning value AG [i]. This basic learning value AG [i] is learned and updated based on the change tendency of the feedback correction term F. Specifically, the value obtained by subjecting the feedback correction term F to the gradual change processing is stored as a new basic learning value AG [i] corresponding to the basic learning region i determined by the engine speed NE at that time. With this basic learning value AG [i], the ignition timing (specifically, the ignition timing command value ST) is steadily corrected so as to suppress the occurrence of knocking. Each basic learning value AG [i] is stored in the RAM 30a of the electronic control unit 30. In the gradual change process, for example, if the basic learning value AG [i] updated in the immediately preceding calculation cycle is “previous learning value” and a positive number of 1.0 or more is “n”, the relational expression [AG The basic learning value AG [i] is calculated through [i] = {“previous learning value” × (n−1) + “feedback correction term F”} / n].

  As shown in FIG. 2, the ignition timing command value ST is normally set to a knock limit ignition timing (BT-R) by correcting the knock limit ignition timing (BT-R) with a basic learning value AG [i]. The value corresponds to the time on the more advanced side than). In this state, when the feedback correction term F is increased / decreased depending on whether knocking has occurred, the ignition timing command value ST is increased / decreased by the increase / decrease of the feedback correction term F as indicated by the arrow Y1 or Y2 in the figure. To do. Then, the value obtained by gradually changing the feedback correction term F that increases and decreases in this way is stored as a new basic learning value AG [i], whereby the basic learning value AG [i] is updated.

  By the way, when a change with time of the internal combustion engine 10 such as deposit adheres to the combustion chamber 11 of the internal combustion engine 10, knocking may easily occur in the internal combustion engine 10. The value AG [i] is updated to a value on the decrease side. The update amount of the basic learning value AG [i] in this case is a value corresponding to the shift amount at which the knock limit of the ignition timing shifts to the retard side timing due to the change over time of the internal combustion engine 10. Therefore, by correcting the ignition timing (directly the knock limit ignition timing (BT-R)) using the updated basic learning value AG [i], knocking occurs with the time-dependent change of the internal combustion engine 10. The occurrence of inconvenience such as being easy to do is suppressed.

  However, the influence on the occurrence of knocking due to the change over time of the internal combustion engine 10 may be greatly different for each smaller engine operation region in the region i, even in the same basic learning region i. is there. In such a case, when the ignition timing is corrected using only the basic learning value AG [i] set for each basic learning region i, the basic learning is performed depending on the engine operating state in the basic learning region i. The value AG [i] may be an inappropriate value for suppressing the occurrence of knocking due to the change of the internal combustion engine 10 with time. Specifically, in order to suppress the occurrence of knocking, the basic learning value AG [i] is too large to prevent the occurrence of knocking effectively, or the basic learning value AG [i] is small. There is a possibility that the ignition timing is excessively corrected to the retard side and the output of the internal combustion engine 10 is reduced due to an excessive value.

  In the present embodiment, the ignition timing command value ST is obtained from the following relational expression (1) based on the knock limit ignition timing (BT-R), the feedback correction term F, and the total learned value AGT.

ST = (BT−R) + F + AGT (1)

The total learning value AGT in the relational expression (1) is a value obtained from the following relational expression (2) based on the basic learning value AG [i] and the multipoint learning value AGdp [n].

AGT = AG [i] + AGdp [n] (2)

The multipoint learning value AGdp [n] in the relational expression (2) is the same as the change over time with respect to the occurrence of knocking when the time change of the internal combustion engine 10 occurs, for example, deposits adhere to the combustion chamber 11 of the internal combustion engine 10. This is a correction term for correcting the ignition timing (specifically, the ignition timing command value ST) in a manner corresponding to the variation in influence. Each multipoint learning value AGdp [n] is stored in the RAM 30a of the electronic control unit 30.

  In the present embodiment, the operating state of the internal combustion engine 10 (specifically, the engine load KL and the engine rotational speed NE) is within a region in the basic learning region i where the variation of the influence of the internal combustion engine 10 with respect to the occurrence of knocking is large. A plurality of multi-point learning areas n that are finer than the basic learning area i divided according to the above are set. The multipoint learning value AGdp [n] is set for each multipoint learning area n.

  The multipoint learning value AGdp [n] is updated based on the feedback correction term F, with the value corresponding to the multipoint learning region n including the operation state of the internal combustion engine 10 at that time being included. The update of the multipoint learning value AGdp [n] is basically a new multipoint learning using a value obtained by subjecting the feedback correction term F to the gradual change process in the same manner as the update of the basic learning value AG [i]. For example, the value AGdp [n] is stored.

  By updating the multipoint learning value AGdp [n] in this way, in a region where the variation of the influence of the internal combustion engine 10 with respect to the occurrence of knocking is large, the multipoint learning region is subdivided according to the variation. The multipoint learning value AGdp [n] for each n can be set to an appropriate value for suppressing the occurrence of knocking.

  In the present embodiment, when the current operating state of the internal combustion engine 10 is in the multipoint learning area n, the basic learning value AG [i] of the basic learning area i in which the multipoint learning area n exists is updated. The multipoint learning value AGdp [n] is only updated. That is, when the engine operating state is included in any of the multipoint learning regions n, only the multipoint learning value AGdp [n] is learned, and the engine operating state is included in a region other than the multipoint learning region n. Only the basic learning value AG [i] is learned.

  When the ignition timing command value ST is obtained, if the current operating state of the internal combustion engine 10 is included in any of the plurality of multipoint learning regions n, the same operating state is set as the multipoint learning value AGdp [n]. A value corresponding to the multipoint learning region n including is used. On the other hand, when the operating state of the internal combustion engine 10 at that time is not included in any of the plurality of multipoint learning regions n, “0” is set as the multipoint learning value AGdp [n]. That is, when the current engine operating state is not included in any of the plurality of multipoint learning regions n, the ignition timing command value ST is calculated without using the multipoint learning value AGdp [n], and the multipoint The ignition timing is not corrected by the learned value AGdp [n].

  By determining the ignition timing command value ST in this manner, knock limit ignition is performed in a region (multi-point learning region n) that is within the basic learning region i and has a large variation in the influence of aging of the internal combustion engine 10 on the occurrence of knocking. The correction is applied to both the basic learning value AG [i] and the multipoint learning value AGdp [n] with respect to the time (BT-R).

  As a result, even in a region where the variation in the occurrence of knocking due to the change over time of the internal combustion engine 10 is large within the basic learning region i, the occurrence of steady knocking in the internal combustion engine 10 due to the change over time etc. It becomes possible to suppress accurately. In other words, in the basic learning region i, where the variation in the influence on the occurrence of knocking due to the time-dependent change of the internal combustion engine 10 is large, the ignition timing is corrected to the advance side from the appropriate timing, so that the occurrence of knocking is effective. Therefore, it is possible to suppress the occurrence of problems such as being unable to be suppressed or the ignition timing being corrected to the retard side from the appropriate timing and causing the output of the internal combustion engine 10 to decrease. In the present embodiment, the processing relating to the calculation of the ignition timing command value ST described above functions as setting means and permission means.

FIG. 3 shows how the multipoint learning area n is set.
As shown in FIG. 3, the plurality of multi-point learning areas n are within the basic learning area i [i = 1] that is present on the lowest rotation side in the direction of change of the engine rotation speed NE among the plurality of basic learning areas i. Are set in the low load region in the direction of change of the engine load KL. This is because, in such a region, variation in the degree of influence caused by the change with time of the internal combustion engine 10 with respect to the occurrence of knocking becomes large. This region is divided into four in the change direction of the engine rotational speed NE and is divided into six in the change direction of the engine load KL, so that a total of 24 multipoint learning regions n [ n = 1 to 24] are set. In the present embodiment, the multipoint learning area n functions as the first engine operation area, the multipoint learning value AGdp [n] functions as the first learning value, and the basic learning area i [i = 1]. The region excluding the multi-point learning region n functions as the second engine operation region, and the basic learning value AG [i] corresponding to the basic learning region i [i = 1] functions as the second learning value.

  Here, regarding the change of the ignition timing command value ST depending on whether or not the internal combustion engine 10 has changed over time, the difference between the multipoint learning region n and the other regions in the basic learning region i [i = 1] on the lowest rotation side. Will be explained.

  FIG. 4 shows an example of how the ignition timing command value ST changes depending on whether or not the internal combustion engine 10 changes with time in an area other than the multipoint learning area n in the basic learning area i [i = 1]. is there. Note that the solid line and the two-point difference line in the figure both show an example of the transition of the ignition timing command value ST with respect to the change in the engine load KL under the condition that the engine speed NE is constant, and the solid line shows the internal combustion engine 10. One example of the transition under the condition without change over time, and the two-dot difference line shows one example of the transition under the condition with change over time.

  As shown in FIG. 4, in a region other than the multi-point learning region n within the basic learning region i [i = 1], when the internal combustion engine 10 changes with time and knocking is likely to occur, the ignition timing command value ST is From the state indicated by the solid line to the state indicated by the two-point difference line, the change direction of the engine load KL changes to the retard side with a uniform width. The amount of change of the ignition timing command value ST toward the retard side is such that the basic learning value AG [i] in the basic learning region i is retarded in order to suppress the occurrence of knocking due to the occurrence of change over time in the internal combustion engine 10. Corresponds to the change that changed to the side. Through such correction of the ignition timing by the basic learning value AG [i], knocking is likely to occur due to a change with time of the internal combustion engine 10 in a region other than the multipoint learning region n in the basic learning region i [i = 1]. It can be suppressed. This is because, within the above region, the influence of the change over time of the internal combustion engine 10 on the occurrence of knocking is almost uniform.

  On the other hand, FIG. 5 shows a region in which each multipoint learning region n is set in the basic learning region i [i = 1] (here, for example, a region corresponding to the multipoint learning region n where n = 1 to 6). The change in the ignition timing command value ST depending on whether or not the internal combustion engine 10 has changed with time is shown. The solid line and the broken line in the figure both show an example of the transition of the ignition timing command value ST with respect to the change in the engine load KL under the condition that the engine speed NE is constant, and the solid line shows no change over time of the internal combustion engine 10. An example of the transition under the condition of (2), and the broken line shows an example of the transition under the condition with the change over time.

  As shown in FIG. 5, in the multi-point learning region n within the basic learning region i [i = 1], when the internal combustion engine 10 changes with time and knocking is likely to occur, the ignition timing command value ST is indicated by a solid line. The state changes from the state to the state shown by the broken line to the retard side with a different width for each engine load KL. The amount of change in the ignition timing command value ST toward the retard side includes knocking caused by the change over time of the internal combustion engine 10 in addition to the change in the basic learning value AG [i] toward the retard side. In order to suppress it, the amount of change of the multipoint learning value AGdp [n] of each multipoint learning region n to the retard side is also included.

  In the present embodiment, in the basic learning region i [i = 1] and in the region where each multipoint learning region n is set, knocking is likely to occur due to changes over time of the internal combustion engine 10. It can be suppressed through correction of the ignition timing by the point learning value AGdp [n]. This is because even if the degree of the influence of the internal combustion engine 10 on the occurrence of knocking varies greatly for each multipoint learning region n, the multipoint learning value for each multipoint learning region n subdivided in consideration of the variation. This is because AGdp [n] is updated to an appropriate value for suppressing the occurrence of knocking, and the ignition timing is corrected using these multipoint learning values AGdp [n].

  Incidentally, the influence of the change over time of the internal combustion engine 10 on the occurrence of knocking in a plurality of multipoint learning areas n is set to a lower speed side in which the engine speed NE in these multipoint learning areas n (see FIG. 3) is low. The larger the area. In addition, the above-described influence is greatest in a region including a specific engine load KL (for example, the median value of the width of the engine load KL including all the multipoint learning regions n) among the plurality of multipoint learning regions n. The smaller the region, the smaller the region. Therefore, each multi-point learning value AGdp [n] becomes a smaller value corresponding to the multi-point learning region n located on the low rotation side of the internal combustion engine 10, and includes a specific engine load KL. There is a tendency that the value corresponding to the region close to n becomes smaller.

  Here, when the operating environment (for example, the temperature and humidity of the intake air) of the internal combustion engine 10 changes, or the property (for example, the octane number) of the fuel supplied to the internal combustion engine 10 changes due to the fuel supply to the fuel tank 14. Thereafter, since the occurrence of knocking changes, the feedback correction term F also changes. Therefore, the state where the multipoint learning value AGdp [n] is learned in accordance with the operating state of the internal combustion engine 10 as in the device according to the present embodiment and the state where learning is prohibited (basic learning value AG [i] When the operating environment and the fuel properties change as described above, there is a possibility that the following inconvenience may occur.

  That is, when the internal combustion engine 10 is operated in the multipoint learning region n immediately after the change of the operating environment and the fuel property, the ignition timing (specifically, the feedback correction term F) is changed due to the change. This is reflected in the multipoint learning value AGdp [n] for compensating for the change in the ignition timing due to the change over time of the engine 10 (specifically, the variation in the degree of influence on the ignition timing due to the change over time). This is not preferable because both the basic learning value AG [i] and the multi-point learning value AGdp [n] are learned to a value that is suitable for the compensation target, and this is a factor that hinders it.

  Based on this point, in the present embodiment, the degree of restriction on the learning amount per unit period of each multipoint learning value AGdp [n] is the restriction on the learning amount per unit period of each basic learning value AG [i]. The learning amount of the basic learning value AG [i] and the multipoint learning value AGdp [n] is limited so as to be larger than the degree. Specifically, by limiting the learning amount per unit period of each multipoint learning value AGdp [n] and not limiting the learning amount per unit period of each basic learning value AG [i], the multipoint learning value AGdp [ n] is larger than the basic learning value AG [i].

Hereinafter, the effect | action by restrict | limiting the variation | change_quantity of each multipoint learning value AGdp [n] like that is demonstrated.
When the operating environment of the internal combustion engine 10 and the properties of the supplied fuel change greatly, the ignition timing (specifically, the feedback correction term F) changes rapidly accordingly. Therefore, it is desirable that the basic learning value AG [i] for compensating for the change in the ignition timing due to the change in the operating environment and the fuel property is set to a value that changes rapidly in accordance with the sudden change in the ignition timing. . On the other hand, the change in the ignition timing accompanying the change with time of the internal combustion engine 10 proceeds slowly over a long period. Therefore, as the multipoint learning value AGdp [n] for compensating for the change in the ignition timing due to the change of the internal combustion engine 10 with time, a value that changes at a slow speed in accordance with the change in the ignition timing is set. Good.

  In the present embodiment, the degree of restriction of the learning amount of the multipoint learning value AGdp [n] that is learned in the multipoint learning region n where the variation in the degree of influence on the ignition timing due to the change of the internal combustion engine 10 with time is large. Therefore, the multipoint learning value AGdp [n] can be learned in accordance with the change of the ignition timing that progresses slowly with the progress of the change with time of the internal combustion engine 10, and the multipoint learning value AGdp [n] It is possible to appropriately learn the change in the ignition timing that accompanies the change with time of the engine 10. In addition, when the operating environment of the internal combustion engine 10 and the properties of the supplied fuel are in the multipoint learning region n immediately after the change, the ignition timing changes greatly at this time, but the change is applied to the multipoint learning region n. Reflection amount can be kept small. For this reason, it is possible to suppress a reflection amount erroneously reflected in the multipoint learning value AGdp [n] of the change in the ignition timing accompanying the change in the operating environment and the fuel property.

  Further, in the present embodiment, the learning amount of the basic learning value AG [i] that is learned in the basic learning region i in which the variation in the degree of the influence on the ignition timing due to the temporal change of the internal combustion engine 10 is small is not limited. For this reason, when the operating environment of the internal combustion engine 10 and the properties of the supplied fuel change greatly, the basic learning value AG [i] quickly changes in accordance with the rapid change of the ignition timing accompanying the change. Based on the basic learning value AG [i], it is possible to appropriately learn the change in the ignition timing due to the change in the operating environment and the properties of the supplied fuel.

  As described above, according to the present embodiment, when the operating environment of the internal combustion engine 10 and the properties of the supplied fuel change, the change in the ignition timing due to the change is erroneously reflected in the multipoint learning value AGdp [n]. This change can be quickly reflected in the basic learning value AG [i], and the ignition timing can be appropriately learned.

  By the way, in the apparatus according to the present embodiment, once the power cable is disconnected from the terminal of the storage battery 22 and the connection between the electric circuit for supplying power to the internal combustion engine 10 and its peripheral devices and the storage battery 22 is once released. The stored value stored in the RAM 30a of the electronic control device 30 is lost. As a result, each basic learning value AG [i] and each multipoint learning value AGdp [n] that have been sequentially learned until then are lost. Therefore, when the electric circuit and the storage battery 22 are reconnected after that, each multi-point learning value AGdp [n] and each basic learning value AG [i] become a value deviating from a value suitable for the actual situation. There is a possibility that it takes a long time for the multi-point learning value AGdp [n] and the basic learning value AG [i] to be learned and become values suitable for the actual situation. In particular, in the apparatus according to the present embodiment, since the learning amount of the multipoint learning value AGdp [n] is limited, the time required for the multipoint learning value AGdp [n] to become a value suitable for the actual situation. It tends to be very long.

  Therefore, in the present embodiment, when the work of connecting the storage battery 22 to the electric circuit (specifically, the work of attaching the power cable to the terminal of the storage battery 22) is performed, multipoint learning is performed over a predetermined period thereafter. The restriction on the learning amount of the value AGdp [n] is temporarily lifted.

  As a result, when the multipoint learning value AGdp [n] disappears, the multipoint learning value AGdp [n] can be temporarily changed to a state in which the multipoint learning value AGdp [n] can be quickly changed. n] can be changed at an early stage to a value commensurate with the actual situation (specifically, a value corresponding to the degree of progress of the internal combustion engine 10 over time).

Hereinafter, learning processing including processing for limiting the amount of change of the multipoint learning value AGdp [n] (limit processing) and processing for canceling the limitation will be described with reference to the flowchart shown in FIG.
Note that the series of processing shown in this flowchart conceptually shows the specific execution procedure of the learning processing, and the actual processing is executed by the electronic control unit 30 as interruption processing for each predetermined crank angle. Is done.

  As shown in FIG. 6, in this process, first, it is determined whether or not the operating state of the internal combustion engine 10 is included in the multipoint learning region n (step S101). If the multi-point learning area n is not included (step S101: NO), learning of the basic learning value AG [i] is executed assuming that the operating area of the internal combustion engine 10 is the basic learning area i ( Step S102). In this case, as described above, the value obtained by subjecting the feedback correction term F to the gradual change processing is stored as the basic learning value AG [i]. That is, the learning amount per unit period of the basic learning value AG [i] is not limited.

  On the other hand, if it is the multipoint learning region n (step S101: YES), a value (gradual change value Vf) obtained by subjecting the feedback correction term F to a gradual change process is calculated (step S103). Thereafter, the restriction process (steps S105 to S110) is executed on condition that a predetermined period T3 or more has elapsed since the operation of connecting the storage battery 22 to the electric circuit was performed (step S104: YES). In the electronic control unit 30 (specifically, the RAM 30a), the operation switch 36 is operated to stop the operation of the internal combustion engine 10 after the operation switch 36 is operated to start the operation of the internal combustion engine 10. The count number (trip number “initial value = 0”) with 1 period as the count is stored. In the process of step S104, it is determined that the predetermined period T3 or more has elapsed if the number of trips stored in the electronic control unit 30 is equal to or greater than a predetermined value (“3” in the present embodiment). . In the present embodiment, the restriction process functions as a restriction unit.

  In the limiting process, first, a value (initial learning value) when the multipoint learning value AGdp [n] corresponding to the multipoint learning region n including the engine operating state at this time is the same multipoint learning region n. The absolute value of the difference between the gradual change values Vf (= “initial learning value” −Vf) is calculated as the same region change amount ΔVf1 (step S105). Here, the same multipoint learning value AGdp [n] in a period (unit period T1) in which the multipoint learning value AGdp [n] is continuously learned in the same multipoint learning area n as the same area change amount ΔVf1. The amount of change is calculated.

  Further, at the time of engine start with respect to the multipoint learning value AGdp [n] corresponding to the multipoint learning region n including the engine operating state at this time (in this embodiment, an operation switch for starting the operation of the internal combustion engine 10). The absolute value of the difference (= “learning value at start time” −Vf) between the value (starting learning value) at 36 and the gradual change value Vf is calculated as the change amount ΔVf2 after starting. Here, as the change amount ΔVf2 after starting, the same multipoint learning value AGdp [n] in the period (unit period T2) from the last operation of the operation switch 36 for starting the operation of the internal combustion engine 10 to the present time. The amount of change is calculated.

  Thereafter, it is determined whether or not the same region change amount ΔVf1 is larger than a predetermined value A (for example, 1.0 “° CA”) (step S106). The predetermined value A is an allowable limit amount that determines the allowable limit of the same region change amount ΔVf1, and a value that can appropriately suppress erroneous learning of the multipoint learning value AGdp [n] is a result of an experiment or simulation. Based on the above, it is obtained in advance and stored in the electronic control unit 30.

  When the same region change amount ΔVf1 is larger than the predetermined value A (step S106: YES), it is determined whether or not the post-startup change amount ΔVf2 is larger than a predetermined value B (for example, the number “° CA”, where B> A). (Step S107). The predetermined value B is an allowable limit amount that determines the allowable limit of the variation ΔVf2 after starting, and a value that can appropriately suppress erroneous learning of the multipoint learning value AGdp [n] It is obtained in advance based on the result and stored in the electronic control unit 30.

  If the after-start change amount ΔVf2 is less than or equal to the predetermined value B (step S107: NO), the after-start change amount ΔVf2 does not exceed the allowable limit amount, but the same region change amount ΔVf1 exceeds the allowable limit amount. As a result, the multipoint learning value AGdp [n] is updated so that the amount of change of the multipoint learning value AGdp [n] in the unit period T1 becomes the predetermined value A (step S108).

  On the other hand, when the after-start change amount ΔVf2 is larger than the predetermined value B (step S107: YES), it is assumed that both the after-start change amount ΔVf2 and the same region change amount ΔVf1 exceed the allowable limit amount as follows. The multipoint learning value AGdp [n] is updated (step S109). Here, the restriction by the predetermined value B is prioritized, and the multipoint learning value AGdp [n] is updated so that the change amount of the multipoint learning value AGdp [n] in the unit period T2 becomes the predetermined value B. The

  Further, when the same region change amount ΔVf1 is equal to or less than the predetermined value A (step S106: NO) and the post-startup change amount ΔVf2 is larger than the predetermined value B (step S110: YES), the post-startup change amount ΔVf2 is an allowable limit. The multipoint learning value AGdp [n] is updated so that the amount of change of the multipoint learning value AGdp [n] in the unit period T2 becomes the predetermined value B, assuming that the amount exceeds the amount (step S109).

  As described above, in this process, when one of the same region change amount ΔVf1 and the post-startup change amount ΔVf2 exceeds the allowable limit amount in the multipoint learning region n, the multipoint learning value AGdp [n] per unit period is exceeded. It is limited in order to prevent the learning amount from becoming excessively large.

  When the same region change amount ΔVf1 is equal to or less than the predetermined value A (step S106: NO) and the after-start change amount ΔVf2 is equal to or less than the predetermined value B (step S110: NO), the same region change amount ΔVf1 and the start The gradual change value Vf is stored as the multipoint learning value AGdp [n], assuming that both the post-change amount ΔVf2 do not exceed the allowable limit amount (step S111). In this case, the learning amount per unit period of the multipoint learning value AGdp [n] is not limited because the learning amount is smaller than the allowable limit amount even though the learning amount is limited in the engine operation region.

  Even when the engine operating state is included in the multipoint learning region n (step S101: YES), the predetermined period T3 has not elapsed after the operation of connecting the storage battery 22 to the electric circuit is performed. In this case (step S104: NO), the limiting process is not executed, and the gradual change value Vf is stored as the multipoint learning value AGdp [n] (step S111). That is, in this case, the multipoint learning value AGdp [n] has disappeared, and the multipoint learning value AGdp [n] may be in a state of being deviated from the value suitable for the actual situation. The restriction on the learning amount of AGdp [n] is released, and the multipoint learning value AGdp [n] is updated. In the present embodiment, the process of step S104 functions as a restriction relaxation unit.

As described above, according to the present embodiment, the effects described below can be obtained.
(1) The degree of restriction on the learning amount per unit period of each multipoint learning value AGdp [n] is larger than the degree of restriction on the learning amount per unit period of each basic learning value AG [i]. The learning amount of the basic learning value AG [i] and the multipoint learning value AGdp [n] is limited. Therefore, when the operating environment of the internal combustion engine 10 and the properties of the supplied fuel change, the change in ignition timing accompanying the change is suppressed from being erroneously reflected in the multipoint learning value AGdp [n] The minute can be quickly reflected in the basic learning value AG [i], and the ignition timing can be appropriately learned.

  (2) By limiting the learning amount per unit period of each multipoint learning value AGdp [n] and not limiting the learning amount per unit period of each basic learning value AG [i], the multipoint learning value AGdp [ n] can be made larger than the limit of the basic learning value AG [i].

  (3) A plurality of multipoint learning areas n divided according to the operating state of the internal combustion engine 10 are set, and a multipoint learning value AGdp [n] is set for each of the multipoint learning areas n. Therefore, in a region where the variation of the influence of the internal combustion engine 10 over time with respect to the occurrence of knocking is large, the multipoint learning value AGdp [n] for each of the multipoint learning regions n obtained by subdividing the region according to the variation is knocked. An appropriate value can be set for suppressing the occurrence. Accordingly, it is possible to suppress the occurrence of problems such that knocking cannot be effectively suppressed or the output of the internal combustion engine is reduced by learning an inappropriate value as the multipoint learning value AGdp [n]. .

  (4) When the operation of connecting the storage battery 22 to the electric circuit is performed, the restriction on the learning amount of the multipoint learning value AGdp [n] is temporarily released over a predetermined period T3 thereafter. . Therefore, when the multipoint learning value AGdp [n] disappears, the multipoint learning value AGdp [n] can be temporarily changed to a state in which the multipoint learning value AGdp [n] can be quickly changed. ] Can be quickly changed to a value that suits the actual situation.

The embodiment described above may be modified as follows.
-The number of sections of the basic learning area i can be arbitrarily changed.
-The number of divisions and the division mode of the multipoint learning area n can be arbitrarily changed.

  As a configuration for limiting the learning amount per unit period of the multipoint learning value AGdp [n], a configuration in which the learning amount per unit period T1 (the same region change amount ΔVf1) is limited by a predetermined value A, and a unit Only one of the configurations in which the learning amount per period T2 (the change amount ΔVf2 after starting) is limited by the predetermined value B may be employed. In addition to or in addition to such a configuration, a configuration in which “a predetermined amount of learning per fixed time is limited by the allowable limit amount” or “a learning amount per execution period of the learning process is an allowable limit” It is possible to adopt a configuration of “limit by amount”.

  The allowable learning amount of the basic learning value AG [i] may be determined to limit the learning amount. When such a configuration is adopted, the degree of restriction on the learning amount per unit period of the multipoint learning value AGdp [n] is larger than the degree of restriction on the learning amount per unit period of the basic learning value AG [i]. By setting the degree of restriction as described above, the effect according to the above embodiment can be obtained.

  The predetermined period for temporarily releasing the restriction on the learning amount of the multipoint learning value AGdp [n] is, for example, a period until the number of executions of the learning process reaches a predetermined number, or the integrated operation of the internal combustion engine 10 It can be arbitrarily changed such as setting a period until the time reaches a predetermined time. The point is that, as such a predetermined period, the state where the multipoint learning value AGdp [n] deviates from the value suitable for the actual situation is resolved at an early stage, and the ignition timing changes due to changes in the operating environment of the internal combustion engine 10 and the properties of the supplied fuel. It is only necessary to set a period in which it is possible to properly prevent the minute from being erroneously reflected in the multipoint learning value AGdp [n].

  When an operation for connecting the storage battery 22 to an electric circuit for supplying electric power to the internal combustion engine 10 and its peripheral devices is performed, the multipoint learning value AGdp [n] per unit period over a predetermined period thereafter. Instead of removing the restriction on the learning amount, the degree of restriction on the learning amount may be temporarily reduced.

1 is a schematic diagram showing a schematic configuration of an internal combustion engine to which an ignition timing control device according to an embodiment embodying the present invention is applied. Explanatory drawing which shows the outline | summary of the calculation procedure of ignition timing command value. Explanatory drawing which shows a basic learning area | region and a multipoint learning area | region. The graph which shows an example of the change aspect of the ignition timing command value by the presence or absence of a time-dependent change of an internal combustion engine. The graph which shows an example of the change aspect of the ignition timing command value by the presence or absence of a time-dependent change of an internal combustion engine. The flowchart which shows the specific execution procedure of a learning process.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... Combustion chamber, 12 ... Intake passage, 13 ... Fuel injection valve, 14 ... Fuel tank, 15 ... Fuel pump, 16 ... Spark plug, 17 ... Piston, 18 ... Crankshaft, 19 ... Exhaust passage, DESCRIPTION OF SYMBOLS 20 ... Accelerator pedal, 21 ... Throttle valve, 22 ... Storage battery, 30 ... Electronic control unit, 30a ... RAM, 31 ... Accelerator sensor, 32 ... Throttle sensor, 33 ... Knock sensor, 34 ... Air quantity sensor, 35 ... Crank sensor, 36: Operation switch.

Claims (8)

The basic value set based on the operating state of the internal combustion engine is corrected by the feedback correction term that is updated according to the presence or absence of knocking and the learning value that is updated based on the feedback correction term to set the control target value of the ignition timing As the learning value, a first learning value that compensates for a change in ignition timing due to a change with time of the internal combustion engine and a second learning value that compensates for a change in ignition timing due to other factors are separately learned. In the internal combustion engine ignition timing control device,
In the first engine operating region where the influence on the ignition timing due to the change over time of the internal combustion engine is large, the basic value is corrected by the first learning value and the second learning value to set the control target value, Setting means for correcting the basic value only by the second learning value and setting the control target value in the second engine operation region where the influence is small;
Permission means for permitting only learning of the first learning value in the first engine operation region and permitting only learning of the second learning value in the second engine operation region;
Limiting means for limiting the learning amount so that a restriction degree of the learning amount per unit period of the first learning value is larger than a restriction degree of the learning amount per unit period of the second learning value; An ignition timing control device for an internal combustion engine, comprising: The ignition timing control device for an internal combustion engine according to claim 1,
The limiting means limits the learning amount per unit period of the first learning value and does not limit the learning amount per unit period of the second learning value. An ignition timing control device for an internal combustion engine, characterized in that a restriction degree is larger than the restriction degree for the second learning value. The ignition timing control device for an internal combustion engine according to claim 1 or 2,
The apparatus comprises a plurality of multi-point learning areas in which the first engine operation area is partitioned according to the engine operation state, and the first learning value is set for each of the multi-point learning areas. An ignition timing control for an internal combustion engine, wherein the first learning value is updated for a region including a current engine operation state among the plurality of multi-point learning regions in the first engine operation region. apparatus. The ignition timing control device for an internal combustion engine according to any one of claims 1 to 3,
The ignition timing control device for an internal combustion engine, wherein the unit period is a period during which the same learning value is continuously learned. The ignition timing control device for an internal combustion engine according to any one of claims 1 to 3,
The unit period is a period from when the operation switch is operated to start the operation of the internal combustion engine to when the operation switch is operated to stop the operation. apparatus. In the ignition timing control device for an internal combustion engine according to any one of claims 1 to 5,
Both the first learning value and the second learning value are values stored in a volatile memory;
The apparatus temporarily limits the degree of restriction on the learning amount over a predetermined period after an operation of connecting a storage battery to an electric circuit for supplying electric power to the internal combustion engine and its peripheral devices is performed. An ignition timing control device for an internal combustion engine, further comprising restriction mitigation means for reducing the internal combustion engine. In the internal combustion engine ignition timing control device according to claim 6,
The ignition timing control device for an internal combustion engine, wherein the restriction relaxing means temporarily releases the restriction on the learning amount. In the ignition timing control device for an internal combustion engine according to any one of claims 1 to 7,
The ignition timing control apparatus for an internal combustion engine, wherein the limiting means limits the learning amount by setting an allowable limit amount that defines an allowable limit for the learning amount.

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