JP2010133280A - Ignition timing controller of internal combustion engine - Google Patents

Abstract

An engine ignition timing at the time of refueling is appropriately learned.
In this apparatus, a control target value of an ignition timing is set such that a multipoint learning value AGdp [n] for compensating for a change in the ignition timing due to a change over time of the internal combustion engine and a change in the ignition timing due to other factors. Is corrected by the basic learning value AG [i] that compensates for. The control target value is corrected by the multipoint learning value AGdp [n] and the basic learning value AG [i] in the multipoint learning region n where the influence on the ignition timing due to the change over time of the internal combustion engine is large, and in the other regions, the control target value is corrected. Correction is made only by the learning value AG [i]. Only the learning of the multipoint learning value AGdp [n] is permitted in the multipoint learning area n, and only the learning of the basic learning value AG [i] is permitted in the other areas. When the basic learning value AG [i] is changed (S101: YES), the multipoint learning value AGdp [is changed to a value changed in the opposite direction to the change amount ΔAG of the basic learning value AG [i]. n] is changed (S103).
[Selection] Figure 6

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. A control target value for the ignition timing is set, and a first learning value for compensating for a change in the ignition timing due to a change with time of the internal combustion engine and a change in the ignition timing due to other factors are compensated as the learning value. In the internal combustion engine ignition timing control apparatus that separately learns the learning value of 2, 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. And an allowance means that, when the second learning value is changed, the first learning value is an amount equal to or less than a change amount of the second learning value in a direction opposite to the change direction of the second learning value. The gist of the present invention is to provide a changing means for changing the value to a value that has only changed.

  In the above configuration, when the operating environment of the internal combustion engine or the property of the fuel supplied to the internal combustion engine changes, the first learning value and the second learning value are corrected in the first engine operation region. Thus, the control target value of the ignition timing is set. Since the learning based on the feedback correction term of the first learning value is executed in accordance with this, the change in the ignition timing accompanying the change in the operating environment and the fuel property is the first learning value, that is, the internal combustion engine. This is reflected in the value for compensating for the change in the ignition timing due to the change over time.

  Thereafter, when the second engine operation region is reached, the ignition target control target value is set by being corrected by the second learning value, and in this state, learning based on the feedback correction term of the second learning value is performed. Will be executed. At this time, the change in the ignition timing due to the change in the operating environment and the fuel properties is reflected in the value for compensating the change, that is, the second learning value that should be reflected. Therefore, the amount of change in the second learning value at this time is an amount commensurate with the amount of change in the ignition timing associated with changes in the operating environment and fuel properties.

  According to the above configuration, when the second learning value is changed as a result of learning as described above, an amount equal to or less than the amount of change (amount commensurate with the change in the ignition timing associated with the change in the operating environment and fuel properties). The first learning value is changed so as to change in the direction opposite to the change direction of the second learning value. As a result, even if the change in the ignition timing due to the change in the operating environment or the fuel property is erroneously reflected in the first learning value, at least a part of the reflected amount is the second learning value. By changing the first learning value at the changed timing, the second learning value is shifted to the first learning value.

  As described above, according to the above configuration, even when the operating environment of the internal combustion engine and the properties of the supplied fuel change, the first learning value and the second learning value can be quickly changed to values suitable for the compensation target. The ignition timing can be appropriately learned.

  According to a second aspect of the present invention, in the ignition timing control device for an internal combustion engine according to the first aspect, the changing means changes the first learned value by an amount equal to a change amount of the second learned value. The gist is to do.

  According to the above configuration, when the change in the ignition timing due to the change in the operating environment or the fuel property is erroneously reflected in the first learning value, the reflection is more quickly changed from the first learning value to the second learning value. It is possible to shift to the learning value.

  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.

  In addition, in a device in which such a multi-point learning area and a multi-point learning value are set, the first learning value (specifically, the multi-point learning value) is changed in accordance with the change of the second learning value. In doing so, as in claim 4, it is possible to adopt a configuration in which all of the plurality of multi-point learning regions are collectively changed.

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. 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) 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 a sensor, for example, an accelerator sensor 31 for detecting the depression amount of the accelerator pedal 20 (accelerator depression amount AC), or an opening degree of the throttle valve 21 provided in the intake passage 12 (throttle opening degree TA) is detected. A throttle sensor 32 for detecting the occurrence of knocking in the internal combustion engine 10 and a knock sensor 33 for detecting occurrence of knocking are provided. In addition, the air amount sensor 34 for detecting the amount of air passing through the intake passage 12 (passage air amount GA), and the rotational speed (engine rotational speed NE) and rotational angle (crank angle) of the crankshaft 18 are detected. A crank sensor 35 and the like are 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.

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, a 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. In the above 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 [ The basic learning value AG [i] is calculated through AG [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.

  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. Specifically, in the same manner as the update of the basic learning value AG [i], the value obtained by subjecting the feedback correction term F to the gradual change process is stored as a new multipoint learning value AGdp [n]. AGdp [n] is updated.

  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, the variation in the degree of influence caused by the change over 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 of the internal combustion engine 10 (for example, the temperature or humidity of the intake air) changes or the property (for example, octane number) of the fuel supplied to the internal combustion engine 10 changes, the occurrence of knocking thereafter In order to change, 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, the following inconvenience occurs.

  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.

In view of such a situation, in this embodiment, a reflection process described in detail below is executed. In this embodiment, this reflection process functions as a changing unit.
Hereinafter, the reflection process will be described with reference to FIG.

  FIG. 6 is a flowchart showing a specific execution procedure of the reflection process. A series of processes shown in this flowchart is executed by the electronic control unit 30 as an interrupt process for each predetermined crank angle.

  As shown in FIG. 6, in this process, first, it is determined whether or not the basic learning value AG [i] in the basic learning region i [i = 1] on the lowest rotation side has changed (step S101). Here, it is determined that the basic learning value AG [i] has changed because the value A of the basic learning value AG [i] at the previous execution of this process is different from the value B at the time of the current execution. .

  When it is determined that the basic learning value AG [i] has changed (step S101: YES), a change amount ΔAG (= BA) of the basic learning value AG [i] is calculated ( In step S102, the multipoint learning value AGdp [n] of each multipoint learning region n is changed in the direction opposite to the change direction of the basic learning value AG [i] by the change amount ΔAG (step S103). Thereafter, this process is temporarily terminated.

  On the other hand, if it is determined that the basic learning value AG [i] has not changed (step S101: NO), the multipoint learning value AGdp [n] is not changed (step S102 and step S103). The process is temporarily terminated by jumping the process).

Hereinafter, the effect by performing such a reflection process is demonstrated, referring FIG.
FIG. 7 shows the total learning value AGT when the operating state of the internal combustion engine 10 shifts as “multi-point learning region n” → “basic learning region i [i = 1]” → “multi-point learning region n”. An example of the transition is shown. FIG. 7A shows an example of transition of the total learning value AGT when the operating environment of the internal combustion engine 10 and the properties of the supplied fuel hardly change. FIG. 7B shows an example of the transition of the total learning value AGT when the operating environment and fuel properties change and the reflection processing is not executed. FIG. 7C shows the operating environment and fuel properties changed. In this case, an example of the transition of the total learning value AGT when the reflection process is executed is shown.

  As shown in FIG. 7A, when the operating environment of the internal combustion engine 10 and the properties of the supplied fuel do not change, the multipoint learning value AGdp [n] and the basic learning value AG [i] hardly change. When the operating state of the internal combustion engine 10 shifts as described above, the previous value and the current value of the total learning value AGT in the multipoint learning region n do not become significantly different.

  On the other hand, when the operating environment of the internal combustion engine 10 and the properties of the supplied fuel change, the multipoint learning value AGdp [n] and the basic learning value AG [i] are updated and changed. Therefore, as shown in FIG. 7B, when it is assumed that the reflection process is not executed, the change in the basic learning value AG [i] (the arrow in the figure) when the multipoint learning area n is reached again. The current value and the previous value of the total learning value AGT are different from each other by the change indicated by C2.

  Specifically, when the operating environment and the fuel properties change, the knocking occurrence state changes thereafter, so that the feedback correction term F also changes. At this time, if the engine operating state is the multipoint learning region n, the multipoint learning value AGdp [n] is updated and learned based on the feedback correction term F in order to adjust the ignition timing to an appropriate timing. . Therefore, even though the ignition timing (specifically, the feedback correction term F) has changed due to changes in the operating environment and fuel properties at this time, a correction amount (a change indicated by an arrow C1 in the figure) for compensating the change amount. Min) is reflected in the multipoint learning value AGdp [n], that is, a value for compensating for a change in ignition timing due to a change with time of the internal combustion engine 10.

  Thereafter, when the engine operating state becomes the basic learning region i [i = 1] on the side with the lowest engine speed NE, in the example shown in FIG. 7B, the basic learning value AG [ Since the learning of i] is not executed, the basic learning value AG [i] at this time is a value commensurate with the operating environment and fuel properties before the change. Therefore, the feedback correction term F changes thereafter, and the basic learning value AG [i] corresponding to the basic learning region i [i = 1] adjusts the ignition timing to an appropriate timing according to the change. Updated and learned. As a result, the correction amount (the change indicated by the arrow C2 in the figure) that compensates for the change in the ignition timing due to the change in the operating environment and the fuel property is already learned through the multipoint learning value AGdp [n]. Despite being reflected in the value AGdp [n], it is also reflected in the basic learning value AG [i] corresponding to the basic learning region i [i = 1].

  Therefore, when the engine operation state is further changed to the multipoint learning region n after that, the multipoint learning value AGdp [n] in which the correction amount (C1) is reflected and the basic learning value AG in which the correction amount (C2) is reflected. Based on [i], the ignition timing command value ST is set, and the ignition timing deviates from an appropriate timing by a change indicated by an arrow C2 in the drawing. If the ignition timing is deviated in this manner, the ignition timing may be inappropriate for suppressing the occurrence of knocking or may be a timing that causes a decrease in engine output.

  In the present embodiment, the reflection process is executed when the ignition timing deviates from an appropriate timing as described above. That is, as shown in FIG. 7C, the multipoint learning value AGdp [n] of each multipoint learning region n is changed by the change of the basic learning value AG [i] (in the figure, the absolute value of the arrow C3 [= {C2 Value}] is changed to a value in the opposite direction to the direction of change of the basic learning value AG [i].

  Specifically, first, when the engine operation state becomes the basic operation region i [i = 1], the basic learning value AG [i] corresponding to the basic operation region i [i = 1] is set as the total learning value AGT. Therefore, at this time, the ignition timing command value ST is set by being corrected only by the basic learning value AG [i]. At this time, learning based on the feedback correction term F of the basic learning value AG [i] corresponding to the basic operation region i [i = 1] is executed.

  Therefore, in the example shown in FIG. 7C, when the basic operation region i [i = 1] is reached, the change in the ignition timing due to the change in the operating environment of the internal combustion engine 10 and the properties of the supplied fuel is It is reflected in the value for compensating the change, that is, the basic learning value AG [i] that should be reflected. For this reason, the amount of change in the basic learning value AG [i] at this time is an amount commensurate with the amount of change in the ignition timing that accompanies changes in the operating environment and fuel properties.

  In the present embodiment, when the basic learning value AG [i] is changed by learning as described above, the change amount ΔAG (that is, the amount commensurate with the change in the ignition timing accompanying the change in the operating environment and the fuel property). ), All the multi-point learning values AGdp [n] are collectively changed so that the basic learning value AG [i] changes in the opposite direction to the change direction by the same amount. Thereby, even if the change in the ignition timing due to the change in the operating environment and the fuel property is erroneously reflected in the multipoint learning value AGdp [n], the reflected amount is reflected in the basic learning value AG [i]. When the multipoint learning value AGdp [n] is changed at the timing when the change is made, the multipoint learning value AGdp [n] is shifted to the basic learning value AG [i].

  As described above, according to the present embodiment, even when the operating environment of the internal combustion engine and the properties of the supplied fuel are changed by executing the reflection process, the multipoint learning value AGdp [n] and the basic learning value AG [ i] can be quickly changed to values suitable for each compensation target, and the ignition timing can be learned appropriately. Therefore, it is possible to prevent the ignition timing command value ST from becoming an inappropriate value for suppressing the occurrence of knocking, or changing too much to the retard side and causing a decrease in engine output.

  In the present embodiment, when the multipoint learning value AGdp [n] is changed in a batch, the multipoint learning value AGdp [n] is changed by an amount equal to the change amount ΔAG of the basic learning value AG [i]. The Therefore, compared with the apparatus of the comparative example that is assumed to change the multipoint learning value AGdp [n] by an amount smaller than the change amount ΔAG for the purpose of suppressing an excessive change in the ignition timing command value ST. The reflected part erroneously reflected in the point learning value AGdp [n] can be quickly transferred from the multipoint learning value AGdp [n] to the basic learning value AG [i].

  Incidentally, even if the multipoint learning value AGdp [n] is not changed in accordance with the change of the basic learning value AG [i] corresponding to the basic operation region i [i = 1], the basic learning value AG [ After i] is learned, when the engine operating state becomes the multipoint learning region n and learning of the multipoint learning value AGdp [n] is executed, the multipoint learning value AGdp [n] matches the compensation target. It gradually changes to the value.

  In this case, however, the ignition timing command value ST is not changed until the engine operating state shifts to the multipoint learning region n after the basic learning value AG [i] has changed as in the example shown in FIG. When calculated, it is inevitable that the ignition timing command value ST is shifted by the change ΔAG of the basic learning value AG [i] (indicated by the arrow C2 in the figure).

  In this regard, in the present embodiment, the multipoint learning value AGdp [n] is matched with the compensation object at the timing when the basic learning value AG [i] changes without waiting for the engine operating state to become the multipoint learning region n. Thus, the ignition timing command value ST can be prevented from shifting by the change amount ΔAG as described above.

As described above, according to the present embodiment, the effects described below can be obtained.
(1) When the basic learning value AG [i] of the basic learning region i [i = 1] changes, the basic learning value AG [i] changes in the opposite direction to the change direction of the basic learning value AG [i]. The multipoint learning value AG [n] is changed to a value changed by an amount equal to the amount ΔAG. Therefore, even if the change in the ignition timing due to the change in the operating environment of the internal combustion engine 10 or the property of the supplied fuel is mistakenly reflected in the multipoint learning value AG [n], the reflected amount is reflected in the basic learning. By changing the multipoint learning value AG [n] at the timing when the value AG [i] changes, the basic learning value AG [i] can be shifted to the multipoint learning value AG [n]. Therefore, even when the operating environment and the fuel properties change, the multipoint learning value AGdp [n] and the basic learning value AG [i] can be quickly changed to values suitable for the compensation object, and the ignition timing can be learned. Can be performed appropriately.

  (2) When the multipoint learning value AGdp [n] is collectively changed, the multipoint learning value AGdp [n] is changed by an amount equal to the change amount ΔAG of the basic learning value AG [i]. Therefore, compared with the comparative apparatus that is assumed to change the multipoint learning value AGdp [n] by an amount that is smaller than the change amount ΔAG, the reflection component erroneously reflected in the multipoint learning value AGdp [n]. Can be quickly shifted from the multipoint learning value AGdp [n] to 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]. .

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.

  The change is not made by changing all the multi-point learning values AGdp [n] at the same time by an amount equal to the change amount ΔAG of the basic learning value AG [i] corresponding to the basic learning region i [i = 1]. All multi-point learning values AGdp [n] may be collectively changed by an amount (= ΔAG × K) obtained by multiplying the amount ΔAG by a predetermined coefficient K (where 0 <K <1.0). According to such a configuration, when the multipoint learning value AGdp [n] is changed in accordance with the change of the basic learning value AG [i], the amount of change can be suppressed small. Therefore, when the multipoint learning value AGdp [n] is erroneously changed for some reason, the influence on the ignition timing can be suppressed to a small value.

  Further, as the predetermined coefficient K, a different value may be set for each change direction of the multipoint learning value AGdp [n]. Specifically, for example, the multipoint learning value AGdp [n] is determined from a predetermined coefficient K (for example, “0.5”) when the multipoint learning value AGdp [n] is changed to an advance value. ] Is changed to a value on the retard side, the predetermined coefficient K (for example, “1.0”) is set to a large value. According to this configuration, when the multipoint learning value AGdp [n] is changed to a retarded value at which knocking is less likely to occur, the multipoint learning value AGdp [n] can be quickly changed. In addition, when the multipoint learning value AGdp [n] is changed to a value on the advance angle side at which knocking is likely to occur, the change amount is suppressed and the occurrence of knocking is suppressed appropriately while the multipoint learning value AGdp [n] is suppressed. ] Can be changed. On the contrary, the multipoint learning value AGdp [n] is changed to a retarded value from a predetermined coefficient K when the multipoint learning value AGdp [n] is changed to an advanced value. It is also possible to set the predetermined coefficient K in the case to a small value.

  Further, as the predetermined coefficient K, a different value may be set for each multipoint learning region n. Specifically, as such a configuration, for example, a predetermined coefficient K (for example, “1.0”) in a region where the engine rotational speed NE is high or a region where the engine load KL is large is used, and a region where the engine rotational speed NE is low or the engine load KL is A configuration in which a value larger than a predetermined coefficient K (for example, “0.5”) in a small region is set. According to this configuration, the multipoint learning value AGdp [n] is quickly changed to an appropriate value in a region where the engine rotational speed NE is high or a region where the engine load KL is large, that is, an engine operation region where knocking is likely to occur. Can do. On the contrary, the predetermined coefficient K in the region where the engine speed NE is high or the region where the engine load KL is high is set to a value smaller than the predetermined coefficient K in the region where the engine speed NE is low or the engine load KL is small. You may make it set.

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 reflection processing. (A)-(c) Explanatory drawing which shows an example of transition of a total learning value.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... Combustion chamber, 12 ... Intake passage, 13 ... Fuel injection valve, 16 ... Spark plug, 17 ... Piston, 18 ... Crankshaft, 19 ... Exhaust passage, 20 ... Accelerator pedal, 21 ... Throttle valve, DESCRIPTION OF SYMBOLS 30 ... Electronic controller, 31 ... Accelerator sensor, 32 ... Throttle sensor, 33 ... Knock sensor, 34 ... Air quantity sensor, 35 ... Crank sensor

Claims (4)

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;
When the second learning value is changed, the first learning value is changed to a value changed by an amount equal to or less than a change amount of the second learning value in a direction opposite to the changing direction of the second learning value. An ignition timing control device for an internal combustion engine, comprising: changing means for changing. The ignition timing control device for an internal combustion engine according to claim 1,
The ignition timing control device for an internal combustion engine, wherein the changing means changes the first learning value by an amount equal to a change amount of 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. In the internal combustion engine ignition timing control device according to claim 3,
The ignition timing control device for an internal combustion engine, wherein the changing means changes all of the plurality of multipoint learning regions at once.

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