JP3721996B2 - Ignition timing control device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ignition timing control device for an internal combustion engine that controls the ignition timing in accordance with the operating state of the internal combustion engine.
[0002]
[Prior art]
As is well known, changing the ignition timing of the internal combustion engine changes the output torque of the engine, the state of occurrence of knocking, and the like. Also, the optimal ignition timing of the internal combustion engine varies depending on the operating state of the engine such as the engine rotational speed, the engine load, the control position of a variable valve timing mechanism (VVT mechanism) that makes the valve timing of the engine valve variable. To do.
[0003]
Conventionally, such an ignition timing control device for controlling the ignition timing of an internal combustion engine usually calculates the ignition timing as follows, for example. That is, first, the basic ignition timing is calculated by map calculation based on the engine speed and the engine load, and further, the calculated basic ignition timing is corrected by the control position of the VVT mechanism, etc. Ask for time. Usually, the ignition timing calculated in this way is an ignition timing (MBT: Minimum advance for the Best Torque) that gives the best output torque and fuel consumption rate of the internal combustion engine under the condition that the occurrence of knocking is suppressed. The closest time is chosen.
[0004]
[Problems to be solved by the invention]
By the way, for example, when the control position of the VVT mechanism is changed, the influence of the ignition timing correction accompanying the change is different depending on the influence on the MBT and the occurrence of knocking.
[0005]
Specifically, when the control position of the VVT mechanism changes, the period (valve overlap period) in which both the intake valve and the exhaust valve of the internal combustion engine are open (valve overlap period) comes to be set or expanded. Then, exhaust gas recirculation (internal EGR) occurs in the combustion chamber of the engine. At this time, since the combustion speed of the air-fuel mixture in the combustion chamber is reduced by the amount of EGR gas as an inert gas introduced into the combustion chamber, the MBT has a more advanced timing. On the other hand, when the valve overlap period is set or extended in this manner, the temperature of the intake air in the combustion chamber rises by the amount of EGR gas introduced into the combustion chamber, and knocking is likely to occur. And in order to suppress the occurrence of such knocking, it is necessary to set the ignition timing to the retard side.
[0006]
However, since the conventional ignition timing control device does not perform such control that clearly intends such a situation, even when correcting the basic ignition timing as described above, the control on the side that has the greater influence, that is, knocking, is eventually achieved. A correction was made to correct the ignition timing to the retarded side in order to suppress the occurrence. For this reason, in some cases, the ignition timing is excessively retarded, and as a result, the output torque of the internal combustion engine is reduced.
[0007]
Not only the ignition timing correction based on the control position of the VVT mechanism described above, but also the ignition timing correction based on the intake air temperature, the cooling water temperature, the fuel increase, etc. These facts are generally common.
[0008]
The present invention has been made in view of the above circumstances, and an object thereof is to provide an ignition timing control device for an internal combustion engine capable of setting a more desirable ignition timing according to various operating states of the internal combustion engine. It is in.
[0009]
[Means for Solving the Problems]
In the following, means for achieving the above object and its effects are described.
First, the invention described in claim 1 is an internal combustion engine that controls the ignition timing of the engine according to the operating state while correcting the basic ignition timing calculated based on the rotational speed and load of the internal combustion engine based on the engine parameter. In this ignition timing control device, the ignition timing correction term based on the engine parameter is determined according to the engine speed and load. The output torque and fuel consumption rate of the internal combustion engine are the best The correction term for the first ignition timing that is the optimal ignition timing and the correction term for the second ignition timing that is the limit ignition timing that can suppress the occurrence of knocking of the engine are obtained separately. The first ignition timing and the second ignition timing are calculated for each basic value based on the rotational speed and load of the engine, and based on the correction term obtained for each. The first and second ignition timings are calculated by correcting the values separately, and the ignition timing to be controlled based on the more retarded value of the calculated first and second ignition timings Is determined, the appropriate value for the second ignition timing is learned based on the occurrence of knocking of the engine, and the control limit is set as a value retarded by a certain value from the second ignition timing. The learning value is reflected in the ignition timing to be controlled as an advance amount from the determined limit retardation value. This is the gist.
[0010]
According to the above configuration, the correction term for the first ignition timing and the correction term for the second ignition timing, which are obtained separately, are determined according to the influence of changes in engine parameters on the first and second ignition timings. It becomes possible to reflect the ignition timing to be controlled in a form. As a result, even when different correction requests are made between the first ignition timing and the second ignition timing in accordance with changes in the engine parameters, the ignition timing to be controlled in a manner corresponding to each of the correction requests. Can be corrected. Therefore, a more desirable ignition timing can be set according to various operating states of the internal combustion engine.
[0012]
further According to the above configuration, the calculation of the basic value based on the rotation speed and the load of the internal combustion engine and the correction of the basic value based on the correction term obtained separately are performed separately, and then the first and second Are respectively calculated. As a result, the different correction requests can be accurately reflected on the first and second ignition timings. Moreover, since the basic value of the ignition timing to be controlled is calculated based on the more retarded value of the first and second ignition timings calculated in this way, the basic value of knocking is used as the basic value. It is possible to determine a suitable value for calculating the timing closest to the optimal ignition timing under the condition that the generation is suppressed.
[0014]
In the above-described conventional ignition timing control device, the reflected amount is usually obtained as the displacement from the basic ignition timing in the learning control of the ignition timing based on the occurrence of knocking. The actual ignition timing in this device is determined by correcting the basic ignition timing based on changes in engine parameters. For this reason, when the engine parameter is changed, the reflected amount is changed by learning the change, and this is one of the causes for reducing the responsiveness of the learning control. In this regard, according to the above configuration, in such learning control, the reflected amount is obtained as a displacement amount from the second ignition timing which is a so-called knock ignition timing. Therefore, the influence of the engine parameter in learning control can be eliminated as much as possible, and the responsiveness of the learning control can be improved.
[0015]
Claims 2 The invention described in claim 1 In the ignition timing control device for an internal combustion engine described above, a limit retardation amount is obtained as a difference between a value on the more retarded side of the first and second ignition timings and the limit retardation value. A retard reflection amount for suppressing the occurrence of knocking in the same engine is obtained as an amount obtained by correcting the obtained limit retarding amount with the learning value and a value indicating the occurrence of knocking in the engine, and the first and second retarding amounts are obtained. The gist of the invention is that the ignition timing to be controlled is determined as a value obtained by correcting the retarded value of the ignition timing by the retarded reflection amount.
[0016]
According to the above configuration, even if the basic value of the ignition timing to be controlled is determined in advance based on the more retarded value of the first and second ignition timings, knocking of the internal combustion engine The retard reflection amount for the basic value for suppressing the generation can be obtained based on the first ignition timing, the second ignition timing, and the limit retardation value.
[0017]
Claims 3 The invention described in claim 1 Or 2 In the internal combustion engine ignition timing control device described above, the internal combustion engine is a variable valve timing mechanism in which the valve overlap period of the engine valve is variably controlled. The gist of the valve overlap period is the variable control.
[0018]
According to the above configuration, for example, a more desirable ignition timing can be set as an ignition timing to be controlled in response to a change in the valve overlap period that has different effects on the MBT and the occurrence of knocking. Become.
[0019]
Claims 4 The invention described in claim 1 3 In the ignition timing control device for an internal combustion engine according to any one of the above, the gist is that the engine parameter for which the correction term is separately obtained is the temperature of the intake air introduced into the combustion chamber of the engine.
[0020]
Claims 5 The invention described in claim 1 4 In the ignition timing control apparatus for an internal combustion engine according to any one of the above, the gist is that the engine parameter for which the correction term is separately obtained is the temperature of the cooling water of the engine.
[0021]
Claims 6 The invention described in claim 1 5 In the ignition timing control device for an internal combustion engine according to any one of the above, the amount of fuel that is increased and corrected in accordance with the operating state of the engine is also used as an engine parameter for correcting the second ignition timing. The gist.
[0022]
Even when the temperature of the intake air introduced into the combustion chamber of the internal combustion engine or the temperature of the cooling water of the engine changes, or when the fuel amount is corrected to increase according to the operating state of the engine, the change or The influence of the ignition timing correction accompanying the execution of the increase correction is different for the influence on the MBT and the influence on the knocking occurrence state. In this regard, the above claims 4 ~ 6 According to the configuration of the invention described in the above, by applying the intake air temperature, the cooling water temperature, or the fuel amount to be corrected for increase as the engine parameter, control should be performed in accordance with the change. A more desirable ignition timing can be set as the ignition timing.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of an ignition timing control device for an internal combustion engine according to the present invention will be described in detail with reference to FIGS.
First, a schematic configuration of an internal combustion engine to which the ignition timing control device according to the embodiment is applied and its peripheral devices will be described with reference to FIG.
[0024]
As shown in FIG. 1, the internal combustion engine 1 includes a cylinder block 1a having a cylinder bore 2 and a cylinder head 1b. A piston 3 provided in the cylinder bore 2 so as to be movable up and down is connected to a crankshaft 10 which is an output shaft of the internal combustion engine 1 via a connecting rod 3a. In the cylinder bore 2, a combustion chamber 4 is defined by a space surrounded by the piston 3 and the cylinder head 1b.
[0025]
The cylinder head 1 b is provided with a spark plug 11 corresponding to the combustion chamber 4. The cylinder head 1b is provided with an intake port 5a and an exhaust port 6a communicating with the combustion chamber 4, and an intake passage 5 and an exhaust passage 6 are connected to the intake port 5a and the exhaust port 6a, respectively. . An intake valve 7 and an exhaust valve 8 are respectively provided at open ends of the intake port 5a and the exhaust port 6a that communicate with the combustion chamber 4. The intake valve 7 and the exhaust valve 8 are opened and closed by intake and exhaust camshafts 31 and 32 that are rotated by the power of the crankshaft 10, respectively. The power of the crankshaft 10 is transmitted to the intake and exhaust camshafts 31 and 32 via a timing belt 35 and timing pulleys 33 and 34.
[0026]
Here, in this embodiment, a structure is adopted in which the relative rotational phase of the intake camshaft 31 with respect to the crankshaft 10 is made variable, and the opening / closing timing of the intake valve 7 is variable according to the rotational speed and load of the internal combustion engine 1. Thus, the torque characteristics of the internal combustion engine 1 can be improved in a wide rotational range. Specifically, a variable valve timing mechanism (VVT mechanism) 50 for continuously changing the relative angle of the intake camshaft 31 to the crankshaft 10 by hydraulic pressure between the intake camshaft 31 and the cam timing pulley 33 is provided. By providing, the timing for opening and closing the intake valve 7 can be continuously changed.
[0027]
A fuel injection injector 9 is provided in the vicinity of the intake port 5a. The injector 9 is supplied with fuel at a predetermined pressure via a fuel supply system (not shown).
[0028]
The operation of the internal combustion engine 1 is started, and fuel is injected from the injector 9 together with the introduction of the intake air into the intake passage 5, whereby the intake air and the fuel are mixed to form an air-fuel mixture. In the intake stroke of the internal combustion engine 1, the intake port 5a is opened by the intake valve 7, whereby the air-fuel mixture is introduced into the combustion chamber 4 through the intake port 5a. Thereafter, the air-fuel mixture introduced into the combustion chamber 4 is ignited by the spark plug 11 and the air-fuel mixture explodes and burns, whereby a driving force is applied to the internal combustion engine 1. The exhaust gas after combustion is discharged into the exhaust passage 6 when the exhaust port 6a is opened by the exhaust valve 8. The ignition operation by the ignition plug 11 is executed according to the application timing of the high voltage applied from the igniter 13 to the ignition plug 11.
[0029]
In addition, a surge tank 16 is provided in the intake passage 5, and a throttle valve 18 that is opened and closed according to the operation of the accelerator pedal 21 is provided on the upstream side of the surge tank 16. The amount of intake air introduced into the intake passage 5 is adjusted according to the opening of the throttle valve 18.
[0030]
The internal combustion engine 1 includes a crank sensor 61 for detecting the rotational phase (crank angle) and the rotational speed (engine rotational speed NE) of the crankshaft 10 as sensors for detecting the operating state, and the internal combustion engine 1. Knock sensor 62 for detecting the occurrence of knocking through the vibration generation state, water temperature sensor 63 for detecting the temperature THW of the cooling water, air flow meter 64 for detecting the intake air amount Ga, and detecting the temperature THA of the intake air. There are provided an intake air temperature sensor 65, a relative rotation phase of the intake camshaft 31 with respect to the crankshaft 10, that is, a VVT sensor 66 for detecting a control position of the VVT mechanism 50, and the like.
[0031]
Further, this apparatus is provided with an electronic control unit (ECU) 60 configured with, for example, a microcomputer, and the output signals of the sensors 61 to 66 are taken into the ECU 60, respectively. . The ECU 60 performs various calculations based on these signals, and controls the fuel injection amount through the drive control of the injector 9 based on the calculation results, the ignition timing control through the drive control of the igniter 13, and the VVT. Various controls relating to the internal combustion engine 1 such as drive control of the mechanism 50 are executed. In this apparatus, the air-fuel ratio of the air-fuel mixture is basically controlled to be the stoichiometric air-fuel ratio (air / fuel = 14.7) through the fuel injection amount control.
[0032]
The ignition timing control device according to the present embodiment can suppress the occurrence of an optimal ignition timing (MBT, referred to as MBT ignition timing in the present embodiment) and knocking determined according to the rotational speed NE and load of the internal combustion engine 1. For the limit ignition timing (knock ignition timing), their basic values (MBT basic value and knock basic value) are calculated separately. At the same time, the apparatus is based on changes in engine parameters such as the control position of the VVT mechanism 50, the intake air temperature THA, the coolant temperature THW, and the fuel amount that is corrected to increase in accordance with the operating state of the internal combustion engine 1. Correction terms are calculated separately for the MBT basic value and the knock basic value.
[0033]
The apparatus calculates the MBT ignition timing and the knock ignition timing by separately correcting the MBT basic value and the knock basic value based on these correction terms, and further controls the control based on both the ignition timings. A basic value (control basic value) of the ignition timing (required ignition timing) to be calculated is calculated. Thereby, the influence on the ignition timing due to the change of each engine parameter is reflected in the required ignition timing.
[0034]
Hereinafter, details of the processing relating to such ignition timing control will be described with reference to FIGS.
Here, first, with reference to FIG. 2, the process of calculating each correction term will be described in detail. This process is executed by the ECU 60 as an interrupt process every predetermined cycle (for example, every crank angle).
[0035]
As shown in FIG. 2, in this process, first, each correction term for the MBT ignition timing is calculated as described in (a) to (c) below (step S100).
(A) “Correction term VVTm”: As described above, when the valve overlap period is set or extended, the MBT ignition timing becomes the advance timing. Therefore, the valve overlap period is determined based on the control position of the VVT mechanism 50, and a correction term VVTk that corrects the MBT ignition timing to the advance side timing as the overlap period is increased is calculated.
(B) “Correction term tam”: When the intake air temperature THA increases, the combustion speed of the air-fuel mixture in the combustion chamber 4 increases, and as a result, the MBT ignition timing becomes a retarded timing. Therefore, the correction term VVTk for correcting the MBT ignition timing to the retard side timing is calculated as the intake air temperature THA increases.
(C) “Correction term thwm”: When the cooling water temperature THW is low, the atomization of the fuel is difficult to be promoted, so that the combustion state of the air-fuel mixture deteriorates and the combustion speed becomes slow. As a result, the MBT ignition timing becomes the advance timing. For this reason, when the coolant temperature THW is low, the correction term VVTk for correcting the MBT ignition timing to the advance side timing is calculated.
[0036]
After the correction terms for the MBT ignition timing are thus calculated, the correction terms for the knock ignition timing are calculated as described in (d) to (g) below (step S101).
(D) “Correction term VVTk”: As described above, when the valve overlap period is set or expanded, the knock ignition timing becomes the retarded timing. Therefore, the correction term VVTk for correcting the knock ignition timing to the retard side is calculated as the overlap period is increased.
(E) “Correction term thak”: When the intake air temperature THA becomes higher, the combustion temperature also becomes higher, so that the knock ignition timing becomes the retarded timing. Therefore, the correction term VVTk for correcting the knock ignition timing to the retard side timing as the intake air temperature THA becomes higher is calculated. However, the correction amount by the correction term VVTk is set larger than the correction amount by the correction term VVTm.
(F) “Correction term thwk”: When the coolant temperature THW is low, that is, when the engine temperature is low, knocking is unlikely to occur, so the knock ignition timing is the advance timing. For this reason, the correction term VVTk that corrects the knock ignition timing to the advance timing as the coolant temperature THW is lower is calculated.
(G) “Correction term Qk”: For example, in an apparatus in which the air-fuel ratio of the air-fuel mixture is set to the above-described stoichiometric air-fuel ratio, the amount of fuel is temporarily increased from the viewpoint of lowering the exhaust gas temperature or improving acceleration performance When corrected, the combustion temperature tends to decrease. As a result, the knock ignition timing becomes the advance timing. Therefore, the correction term Qk for correcting the knock ignition timing to the advance timing when the fuel amount is increased is calculated in this way.
[0037]
After the correction terms for the knock ignition timing are calculated in this way, the present process is temporarily terminated.
Next, the process for calculating the control basic value will be described in detail with reference to FIG. This process is also executed by the ECU 60 as an interrupt process at predetermined intervals (for example, every crank angle).
[0038]
As shown in FIG. 3, in this process, first, an engine load fl (= Ga / NE) is calculated based on the engine rotational speed NE and the intake air amount Ga, and the engine load fl and the engine rotational speed NE are calculated. Based on the map, the MBT basic value Amb is calculated (step S200). The map is a map for calculating the MBT basic value Amb based on the relationship between the engine load fl and the engine speed NE, and is stored in the ECU 60 in advance.
[0039]
After that, the MBT ignition timing Am
Am = Amb + VVTm + tham + thwm
As described above, it is calculated by correcting the MBT basic value Amb by the correction terms VVTm, tam, and thwm (step S201).
[0040]
Thereafter, the knock basic value Akb is calculated from the map based on the engine load fl and the engine speed NE (step S202). The above map is a map for calculating the knock basic value Akb based on the relationship between the engine load fl and the engine speed NE, and this map is also stored in the ECU 60 in advance.
[0041]
After that, the knock ignition timing Ak becomes
Ak = Akb + VVTk + thak + thwk + Qk
As described above, the knock basic value Akb is calculated by correcting with the correction terms VVTk, thak, thwk, and Qk (step S203).
[0042]
Thereafter, the retarded timing is selected from the calculated MBT ignition timing Am and knock ignition timing Ak, and the selected timing is set to the control basic value Absef (step S204). Is temporarily terminated.
[0043]
Next, the process for calculating the required ignition timing will be described in detail with reference to FIGS. This process is also executed by the ECU 60 as an interrupt process at predetermined intervals (for example, every crank angle). 4 and 5 show a processing procedure for calculating the required ignition timing, and FIG. 6 shows an example of how to calculate the required ignition timing in order to facilitate understanding of the above processing. .
[0044]
As shown in FIG. 4, in this process, first, based on the driving state of the vehicle (not shown) such as the engine speed NE, the vehicle speed, the depression amount of the accelerator pedal 21, etc., whether or not the vehicle is in the idle driving state. Is determined (step S301).
[0045]
When it is determined that the vehicle is not in the idling state (step S301: NO), the basic ignition timing Abse is set to the control basic value Absef (step S302). On the other hand, when it is determined that the vehicle is in the idling state (step S301: YES), the basic ignition timing Abse is set to the basic idle value Absei calculated in a process different from the process described above (step S301). S303). The idle basic value Absei is also set in advance after calculating the MBT ignition timing and the knock ignition timing suitable for the idle operation state in a manner in accordance with the setting mode of the control basic value Absef.
[0046]
After that, through the following processing (steps S304 to S317), the basic ignition timing Abse set in this way is retarded by the reflection amount learned based on the occurrence of knocking, thereby calculating the required ignition timing. Is done.
[0047]
That is, first, it is determined whether or not knocking has occurred through the detection signal of the knock sensor 62 (step S304). If it is determined that knocking has occurred (step S304: YES), the knock control amount AKCS (see FIG. 6) is added / updated by a predetermined value A1 (for example, 0.4 ° CA). . “° CA” represents the crank angle. On the other hand, when it is determined that knocking has not occurred (step S304: NO), the knock control amount AKCS is subtracted and updated by a predetermined value A2 (for example, 0.01 ° CA).
[0048]
This knock control amount AKCS is an amount whose magnitude changes according to the current knocking occurrence state of the internal combustion engine 1. Specifically, the knock control amount AKCS sets the required ignition timing to the retarded timing when knocking occurs in the internal combustion engine 1, and conversely, when the knocking does not occur, the required ignition timing is set. Is an amount for controlling the ignition timing in accordance with the state of occurrence of knocking at that time, such as setting the timing to the advance side.
[0049]
After the knock control amount AKCS is updated in this way, it is determined whether or not the knock control amount AKCS is larger than a predetermined value A3 (for example, 2.5 ° CA) (step S307). If it is determined that the value is larger than the predetermined value A3 (step S307: YES), the knock learning amount AGKNK (see FIG. 6) is subtracted / updated by a predetermined value A5 (for example, 0.5 ° CA). (Step S308).
[0050]
On the other hand, when it is determined that knock control amount AKCS is equal to or smaller than predetermined value A3 (step S307: NO), is knock control amount AKCS smaller than predetermined value A4 (for example, 0.5 ° CA)? It is determined whether or not (step S309). If it is determined that the value is smaller than the predetermined value A4 (step S309: YES), the knock learning amount AGKNK is added / updated by a predetermined value A6 (for example, 0.5 ° CA) (step S310).
[0051]
On the other hand, when it is determined that knock control amount AKCS is equal to or smaller than predetermined value A3 and equal to or larger than predetermined value A4 (step S307: NO and step S309: NO), knock learning amount AGKNK is updated. Without moving to the next process.
[0052]
This knock learning amount AGKNK is set relatively small when knocking tends to occur frequently, and conversely, it is set relatively large when the number of occurrences of knocking is small. Therefore, the knock learning amount AGKNK is a value reflecting a factor that constantly affects the occurrence of knocking, such as variations in characteristics of the internal combustion engine 1 and changes with time. Specifically, the required ignition timing is set to the retarded timing as the knock learning amount AGKNK is smaller.
[0053]
After that, the limit retardation value Akmf (see FIG. 6), which is the control limit for the reflection amount learned based on the occurrence of knocking, is delayed from the knock ignition timing Ak by a predetermined value A7 (for example, 15 ° CA). It is obtained as the horned time (FIG. 5: Step S311).
[0054]
Thereafter, it is determined whether or not the limit retardation value Akmf is equal to the basic ignition timing Abse, or whether or not the limit retardation value Akmf is more advanced than the basic ignition timing Abse (step S312). ). When it is determined that the limit retardation value Akmf is equal to the basic ignition timing Abse, or that the limit retardation value Akmf is on the more advanced side than the basic ignition timing Abse (step S312: YES), In the first place, the required ignition timing Acal is set to the basic ignition timing Abse on the assumption that there is no need to perform retardation correction based on the occurrence of knocking (step S313).
[0055]
On the other hand, when it is determined that the limit retard angle value Akmf is on the retard side with respect to the basic ignition timing Abse (step S312: NO), the reflection amount is calculated based on the occurrence of knocking.
[0056]
That is, first, the limit retardation amount Akmax is
Akmax ← Abse-Akmf
That is, it is calculated as a difference between the basic ignition timing Abse and the limit retardation value Akmf (step S314).
[0057]
Then, based on the limit retardation amount Akmax calculated in this way, the knock learning amount AGKNK and the knock control amount AKCS, the knock retardation reflection amount AKNK serving as the reflection amount is
AKNK = Akmax−AGKNK + AKCS
In other words, that is, the limit retardation amount Akmax is calculated as an amount corrected by the knock learning amount AGKNK and the knock control amount AKCS (step S315).
[0058]
Then, it is determined whether or not the knock retardation reflection amount AKNK is equal to or smaller than “0 ° CA” (step S316). When it is determined that the knock retardation reflection amount AKNK is larger than “0 ° CA” (step S316: NO). The required ignition timing Acal is
Acal = Abse-AKNK
In this manner, the delay angle is corrected and set based on the knock delay reflection amount AKNK (step S317).
[0059]
On the other hand, when it is determined that the knock retard reflection amount AKNK is equal to or less than “0 ° CA” (step S316: YES), it is necessary to set the required ignition timing Acal to the advance side with respect to the basic ignition timing Abse. If not, the required ignition timing Acal is set to the basic ignition timing Abse (step S313).
[0060]
After the required ignition timing Acal is thus set (step S313 or step S317), this process is temporarily terminated. In actual control, the required ignition timing Acal determined in this way, for example, ignition timing control for reducing shock associated with resumption of fuel injection immediately after the end of fuel cut, ignition timing control for reducing acceleration shock, etc. The ignition timings determined during the transient control are compared with each other, and the most retarded timing among these ignition timings is selected to determine the reflected ignition timing AOP.
[0061]
The ECU 60 controls the driving of the igniter 13 so that the ignition timing by the spark plug 22 coincides with the reflected ignition timing AOP in a process different from the series of processes described above.
[0062]
As described above, according to the present embodiment, the effects described below can be obtained.
(1) A correction term based on a change in each engine parameter such as a control position of the VVT mechanism 50, an intake air temperature THA, a cooling water temperature THW, and a fuel amount that is corrected to be increased according to the operating state of the internal combustion engine 1 The calculation is performed separately for the basic value Amb and the knock basic value Akb. For this reason, it is possible to reflect the correction term obtained separately for each of the required ignition timings Acal in accordance with the influence of changes in the engine parameters on the MBT ignition timing Am and the knock ignition timing Ak. That is, even when different correction requests are made between the MBT ignition timing Am and the knock ignition timing Ak in accordance with changes in each engine parameter, the required ignition timing Acal is corrected in accordance with each of the correction requests. This makes it possible to set a more desirable ignition timing according to various operating states of the internal combustion engine.
[0063]
(2) The MBT basic value Amb and the knock basic value Akb are calculated separately, and the MBT ignition timing Am and the MBT basic value Amb and the knock basic value Akb are corrected separately by a correction term based on a change in each engine parameter. The knock ignition timing Ak is calculated. For this reason, the correction term based on the change of each engine parameter calculated separately for the MBT basic value Amb and the knock basic value Akb can be accurately reflected on the MBT basic value Amb and the knock basic value Akb. become able to. In addition, since the more retarded timing of the MBT ignition timing Am and the knock ignition timing Ak calculated in this way is set as the control basic value Absef, the occurrence of knocking is suppressed as the control basic value Absef. Therefore, it is possible to set a suitable time for calculating the time closest to the optimum ignition timing.
[0064]
(3) After obtaining the limit retardation value Akmf as a timing delayed by a predetermined value A7 from the knock ignition timing Ak reflecting the respective correction terms VVTk, thak, thwk, Qk, and successively based on the occurrence of knocking The updated knock learning amount AGKNK is reflected in the required ignition timing Acal as the advance amount from the limit retard angle value Akmf. As a result, the influence of the engine parameter in the process of calculating the required ignition timing Acal can be eliminated as much as possible, and the responsiveness of the process can be improved.
[0065]
(4) The retard amount is calculated as a difference between the basic ignition timing Abse and the limit retard angle value Akmf, and the retard delay amount is calculated by correcting the limit retard amount Akmax with the knock learning amount AGKNK and the knock control amount AKCS. After obtaining AKNK, the required ignition timing Acal is set by correcting the basic ignition timing Abse with the retard reflection amount AKNK. Thus, even when the more retarded timing of the MBT ignition timing Am and the knock ignition timing Ak is determined in advance as the basic ignition timing Abse, the delay angle reflection to be reflected in the basic ignition timing Abse is reflected. The quantity AKNK can be determined based on the MBT ignition timing Am, the knock ignition timing Ak, and the limit retard angle value Akmf.
[0066]
The embodiment described above may be modified as follows.
In the above embodiment, correction terms based on changes in the engine parameters are calculated separately for the MBT ignition timing Am and the knock ignition timing Ak, and these correction terms are set for the MBT basic value Amb and the knock basic value Akb, respectively. Although it was made to reflect separately, the aspect which reflects these correction | amendment terms is arbitrary. In short, these correction terms are accurately set for the MBT ignition timing Am and the knock ignition timing Ak in accordance with changes in engine parameters that require different correction requests for the MBT ignition timing Am and the knock ignition timing Ak. Any mode that can be reflected may be used.
[0067]
In the above embodiment, as the engine parameter, the control position of the VVT mechanism 50, the intake air temperature THA, the coolant temperature THW, and the fuel amount that is corrected to increase according to the engine operating state are adopted. Any one, any two, or any three of these engine parameters may be adopted. In addition to the engine parameters described above, any engine parameters that make different correction requests for the MBT ignition timing Am and the knock ignition timing Ak in accordance with the change can be adopted as appropriate.
[0068]
In the above embodiment, the ignition timing control device according to the present invention is applied to the internal combustion engine 1 in which the VVT mechanism 50 that varies the timing for opening and closing the intake valve 7 is mounted. The ignition timing control device according to the present invention may be applied to an internal combustion engine equipped with a VVT mechanism in which the timing for opening and closing the exhaust valve is variable, or the timing for opening and closing the intake and exhaust valves is variable. .
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of an embodiment of an ignition timing control device for an internal combustion engine according to the present invention.
FIG. 2 is a flowchart showing a processing procedure for calculating a correction term for ignition timing.
FIG. 3 is a flowchart showing a processing procedure for calculating a control basic value.
FIG. 4 is a flowchart showing a processing procedure for calculating a required ignition timing.
FIG. 5 is a flowchart showing a processing procedure for calculating a required ignition timing.
FIG. 6 is a graph showing an example of how the required ignition timing is calculated.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 1a ... Cylinder block, 1b ... Cylinder head, 2 ... Cylinder bore, 3 ... Piston, 3a ... Connecting rod, 4 ... Combustion chamber, 5 ... Intake passage, 5a ... Intake port, 6 ... Exhaust passage, 6a ... Exhaust Port, 7 ... Intake valve, 8 ... Exhaust valve, 9 ... Injector, 10 ... Crankshaft, 11 ... Ignition plug, 13 ... Igniter, 16 ... Surge tank, 18 ... Throttle valve, 21 ... Accelerator pedal, 22 ... Ignition plug, 31 ... Intake camshaft, 32 ... Exhaust camshaft, 33, 34 ... Timing pulley, 35 ... Timing belt, 50 ... VVT mechanism, 60 ... ECU, 61 ... Crank sensor, 62 ... Knock sensor, 63 ... Water temperature sensor, 64 ... Air flow meter, 65 ... intake air temperature sensor, 66 ... VVT sensor.

Claims (6)

In an ignition timing control device for an internal combustion engine that controls the ignition timing of the engine according to the operating state while correcting the basic ignition timing calculated based on the rotation speed and load of the internal combustion engine based on the engine parameter,
The correction term for the ignition timing based on the engine parameter is a correction term for the first ignition timing which is the optimum ignition timing at which the output torque and fuel consumption rate of the internal combustion engine determined according to the rotational speed and load of the engine are the best. And a correction term for the second ignition timing which is the limit ignition timing that can suppress the occurrence of knocking in the engine ,
The basic values of the first ignition timing and the second ignition timing are calculated separately based on the rotation speed and load of the engine, and the basic values are calculated based on the correction terms obtained separately. Are corrected separately, and the first and second ignition timings are calculated. Of the calculated first and second ignition timings, the ignition timing to be controlled is controlled based on the more retarded value. The base value is determined,
An appropriate value for the second ignition timing is learned on the basis of the occurrence of knocking in the engine, and a retard value serving as a control limit is obtained as a value retarded by a certain value from the second ignition timing. And the learning value is reflected in the ignition timing to be controlled as an advance amount from the determined limit retardation value . A limit retard amount is obtained as a difference between a more retarded value of the first and second ignition timings and the limit retard value, and the obtained limit retard amount is determined as the learned value and A retarded reflection amount for suppressing the occurrence of knocking in the engine is obtained as an amount corrected with a value indicating the knocking occurrence state of the engine, and a value on the more retarded side of the first and second ignition timings. The ignition timing to be controlled is determined as a value obtained by correcting the retard by the retard reflection amount.
  The ignition timing control device for an internal combustion engine according to claim 1. In the internal combustion engine, the valve overlap period of the engine valve is variably controlled by a variable valve timing mechanism, and the engine parameter for which a correction term is separately required is the variably controlled valve overlap period.
  The ignition timing control device for an internal combustion engine according to claim 1 or 2. The engine parameter for which a correction term is separately required is the temperature of the intake air introduced into the combustion chamber of the engine.
  The ignition timing control device for an internal combustion engine according to any one of claims 1 to 3. The engine parameter for which a correction term is separately obtained is the temperature of the cooling water of the engine.
  The ignition timing control device for an internal combustion engine according to any one of claims 1 to 4. As an engine parameter for correcting the second ignition timing, a fuel amount that is increased and corrected in accordance with the operating state of the engine is also used.
  The ignition timing control device for an internal combustion engine according to any one of claims 1 to 5.

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