JP2010121507A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for setting ignition timing to an appropriate value in transient time with change in EGR gas amount, in a control device for an internal combustion engine. <P>SOLUTION: The control device for an internal combustion engine includes: a first correction means calculating a delay from a reference value of ignition timing when knocking occurs in an operating range where EGR gas is not led; a second correction means setting, as a second reference value, ignition timing delayed from a reference value by the delay calculated by the first correction means when the ignition timing is advanced according to the EGR gas amount in an operating range where the EGR gas is led, and calculating an advance from the second reference value according to the EGR gas amount; and a third correction means setting, as a third reference value, ignition timing advanced from the second reference value by the advance calculated by the second correction means when the ignition timing is delayed when knocking occurs in the operating range where the EGR gas is led, and calculating a delay from the third reference value. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a control device for an internal combustion engine.

  When EGR gas is introduced into the internal combustion engine, the combustion state changes, so the appropriate value of the ignition timing changes. And the technique which determines the control amount of ignition timing based on the amount of EGR gas is known (for example, refer to patent documents 1). According to this technique, the advance amount of the ignition timing is increased as the EGR gas amount increases.

  By the way, since the appropriate value of the ignition timing varies greatly depending on a slight difference in the EGR gas amount, the ignition timing is divided into more operation regions as the operation region into which the EGR gas is introduced and the EGR gas amount is larger. Must be set. This requires a lot of experimentation and takes time.

In addition, there is a possibility that the ignition timing may be advanced or retarded too much during a transition from an operation region where EGR gas is not introduced to an operation region where EGR gas is introduced, or vice versa. As a result, knocking, misfire, drivability, etc. may occur.
JP 2007-16609 A JP-A-8-151971 JP 2005-127154 A JP 2006-291895 A

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a technique for setting an ignition timing to an appropriate value during a transition accompanied by a change in the amount of EGR gas in a control device for an internal combustion engine.

In order to achieve the above object, an internal combustion engine control apparatus according to the present invention employs the following means. That is, the control device for an internal combustion engine according to the present invention provides:
In a control device for an internal combustion engine comprising: an EGR device that reintroduces part of the exhaust gas of the internal combustion engine into the cylinder; and an ignition plug that generates an electric spark in the cylinder.
First correction means for calculating a retard amount from a reference value of the ignition timing when the ignition timing is retarded when knocking occurs in an operation region in which EGR gas is not introduced;
When the ignition timing is advanced according to the amount of EGR gas in the operation region where EGR gas is introduced, the ignition timing obtained by retarding the retardation amount calculated by the first correction means from the reference value is a second value. Second correction means for calculating a lead angle amount from the second reference value according to an EGR gas amount as a reference value;
When the ignition timing is retarded when knocking occurs in the operation region where EGR gas is introduced, the ignition timing obtained by advancing the advance amount calculated by the second correction means from the second reference value is set. Third correction means for calculating a retardation amount from the third reference value as a third reference value;
It is characterized by providing.

The greatest feature of the present invention is that the correction target is changed between an operation region in which EGR gas is not introduced and an operation region in which EGR gas is introduced, and the correction value obtained in the operation region in which EGR gas is not introduced In the operation area to be introduced, it is to be treated as a fixed value as a reference. That is, the second reference value is treated as a fixed value.

  Here, in the operation region where EGR gas is not introduced, the ignition timing is retarded when knocking occurs. The retardation amount at this time may be a predetermined amount or an amount corresponding to the strength of knocking. Here, since the combustion state becomes unstable if the ignition timing is retarded too much, the retard amount may be limited. By retarding the ignition timing in this way, the occurrence of knocking can be suppressed. Further, in the operation region where EGR gas is not introduced, the ignition timing may be advanced when knocking does not occur.

  On the other hand, in the operation region where EGR gas is introduced, the ignition timing is advanced according to the amount of EGR gas. However, if knocking occurs when the ignition timing is advanced, the ignition timing is retarded from the value after the advance. That is, the degree of advance is reduced. The retardation amount when knocking occurs may be a predetermined amount or an amount corresponding to the strength of knocking.

  In the present invention, when the ignition timing is advanced in accordance with the amount of EGR gas in the operation region where EGR gas is introduced, the ignition timing set in the operation region where EGR gas is not introduced is used as the second reference value. That is, the ignition timing after correction in the operation region where EGR gas is not introduced is used as a reference, and the advance according to the amount of EGR gas is performed from that value. By doing so, the retard amount calculated in the operation region where the EGR gas is not introduced is maintained even in the operation region where the EGR gas is introduced. Therefore, when shifting again to the operation region in which the EGR gas is not introduced, it is possible to return to the previously set retardation amount.

  Further, even in the operation region where EGR gas is introduced, the ignition timing is retarded by the occurrence of knocking. At this time, the ignition timing is retarded from the third reference value. That is, even in the operation region where the EGR gas is introduced, it is affected by the retardation amount calculated in the operation region where the EGR gas is not introduced.

  As described above, the correction target is changed before and after the introduction of the EGR gas. Further, by not changing the retard amount calculated in the operation region where the EGR gas is not introduced in the operation region where the EGR gas is introduced, the ignition timing is excessively advanced before and after the introduction of the EGR gas or when the EGR gas amount is changed. It is possible to suppress the angle or the retardation.

  In the present invention, the third correction means calculates the retard amount of the ignition timing when knocking occurs in the operation region where the EGR gas is introduced, and calculates the advance amount of the ignition timing when knocking does not occur. At this time, the limit of the retard amount from the third reference value is set to the same magnitude as the advance amount calculated by the second correction unit, and the limit of the advance amount is calculated by the first correction unit. It may be the same size as the retardation amount.

  This is the same as the retard amount calculated by the first corrector, with the ignition timing retarded from the reference value by the retard amount calculated by the first corrector as a limit on the retard side. This is the same as setting the ignition timing advanced from the third reference value by the amount of advance of the magnitude as a limit on the advance side. Further, it is the same as setting the third reference value when the retardation amount calculated by the first correction means is 0 as the limit of the ignition timing on the advance side.

Here, even if knocking occurs in the operation region where EGR gas is not introduced, knocking does not necessarily occur in the operation region where EGR gas is introduced. That is, if the retard amount of the ignition timing calculated when knocking occurs in the operation region where EGR gas is not introduced is used as it is in the operation region where EGR gas is introduced as it is, the ignition timing may become too late. On the other hand, if the ignition timing is advanced when knocking does not occur, it is possible to suppress the ignition timing from being excessively delayed. However, if the ignition timing is advanced too much, knocking may occur, so a limit is set for the advance amount. This limit is a value obtained by adding the advance amount of the same magnitude as the retard amount calculated by the first corrector to the advance amount calculated by the second corrector. That is, the ignition timing set by the second correction unit when there is no correction by the first correction unit is set to the advance side limit. That is, it is possible to advance the ignition timing until the influence of the first correction means is eliminated. This suppresses the ignition timing from being delayed excessively when knocking does not occur in the operation region where EGR gas is introduced even though knocking occurs in the operation region where EGR gas is not introduced. it can.

  Further, when knocking occurs in the operation region where EGR gas is introduced, the ignition timing is retarded. There is also a limit on the amount of retardation at this time. This limit is a retard amount that is the same as the advance amount calculated by the second correcting means. That is, the ignition timing to which the retard amount calculated by the first correcting means is applied is set as the retard side limit. Thereby, in the operation region in which the EGR gas is introduced, the ignition timing is not retarded as compared with the operation region in which the EGR gas is not introduced, so that it is possible to suppress the ignition timing from being excessively retarded.

  According to the control apparatus for an internal combustion engine according to the present invention, the ignition timing can be set to an appropriate value at the time of transition accompanied by a change in the amount of EGR gas.

  Hereinafter, specific embodiments of a control device for an internal combustion engine according to the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of an internal combustion engine to which the control device for an internal combustion engine according to this embodiment is applied, and its intake system and exhaust system. The internal combustion engine 1 shown in FIG. 1 is a water-cooled four-cycle gasoline engine having four cylinders.

  An intake pipe 4 is connected to the combustion chamber in the cylinder 2 via an intake port 3 provided in the cylinder head 10. Inflow of intake air into the cylinder 2 is controlled by an intake valve 5. Opening and closing of the intake valve 5 is controlled by rotational driving of the intake side cam 6. An exhaust pipe 8 is connected via an exhaust port 7 provided in the cylinder head 10. Exhaust exhaust to the outside of the cylinder 2 is controlled by an exhaust valve 9. Opening and closing of the exhaust valve 9 is controlled by rotational driving of the exhaust side cam 11.

  The piston 15 connected to the crankshaft 13 of the internal combustion engine 1 via the connecting rod 14 reciprocates in the cylinder 2.

  An intake throttle valve 16 that adjusts the amount of intake air flowing through the intake pipe 4 is provided in the middle of the intake pipe 4. An air flow meter 95 that outputs a signal corresponding to the amount of air flowing through the intake pipe is attached to the intake pipe 4 upstream of the intake throttle valve 16. The air flow meter 95 detects the intake air amount of the internal combustion engine 1.

  The internal combustion engine 1 is provided with a knock sensor 94 that detects that knocking has occurred. The knock sensor 94 may measure the strength of knocking.

  Further, the internal combustion engine 1 is provided with an EGR device 30 that recirculates a part of the exhaust gas (hereinafter referred to as EGR gas) flowing through the exhaust pipe 8 to the intake pipe 4. The EGR device 30 includes an EGR passage 31 and an EGR valve 32.

  The EGR passage 31 connects the exhaust pipe 8 and the intake pipe 4 downstream of the intake throttle valve 16. The EGR gas is recirculated through the EGR passage 31. The EGR valve 32 adjusts the amount of EGR gas flowing through the EGR passage 31 by adjusting the passage cross-sectional area of the EGR passage 31.

  A fuel injection valve 81 that injects fuel toward the intake port 3 is attached to the intake pipe 4 in the vicinity of the internal combustion engine 1. The internal combustion engine 1 is provided with a spark plug 82 that generates an electric spark in the cylinder 2.

  Further, the internal combustion engine 1 is provided with an ECU 90 that is an electronic control unit for controlling the internal combustion engine 1. The ECU 90 includes a CPU, a ROM, a RAM, and the like for storing various programs and maps, and a unit that controls the operating condition of the internal combustion engine 1 according to the operating conditions of the internal combustion engine 1 and the driver's request. It is.

  Here, in addition to the various sensors described above, an accelerator opening sensor 91 and a crank position sensor 92 are electrically connected to the ECU 90. The ECU 90 receives a signal corresponding to the accelerator opening from the accelerator opening sensor 91 and calculates an engine load required for the internal combustion engine 1 in accordance with this signal. The ECU 90 receives a signal corresponding to the rotation angle of the output shaft of the internal combustion engine 1 from the crank position sensor 92 and calculates the engine rotational speed of the internal combustion engine 1.

  The ECU 90 introduces EGR gas or adjusts the amount of EGR gas according to the operating state of the internal combustion engine 1.

  In this embodiment, the ignition timing is retarded when knocking occurs in the operation region where EGR gas is not introduced. The retard correction amount at this time is AKNK. Further, in the operation region where the EGR gas is introduced, the ignition timing is advanced in accordance with the amount of EGR gas. The advance angle correction amount at this time is assumed to be AEGR. Further, in the operation region where EGR gas is introduced, the advance angle correction amount AEGR is corrected when knocking occurs.

  As described above, the correction target is different between the operation region where the EGR gas is introduced and the operation region where the EGR gas is not introduced. In other words, the retardation correction amount AKNK calculated in the operation region where EGR gas is not introduced does not change in the operation region where EGR gas is introduced. Therefore, the value of the retardation correction amount AKNK is maintained as it is even in the operation region where the EGR gas is introduced.

  The retard correction amount AKNK is a retard amount from the reference ignition timing ABASE. The reference ignition timing ABASE is a value set in advance so as to suppress the occurrence of knocking and misfire, and is set according to, for example, the operating state (for example, the engine speed and engine load) of the internal combustion engine 1. The reference ignition timing ABASE is obtained in advance through experiments or the like in association with the operating state of the internal combustion engine 1, for example, and is stored in the ECU 90. In the operation region where EGR gas is introduced, the ignition timing is obtained by retarding the retardation correction amount AKNK from the reference ignition timing ABASE. In this embodiment, the reference ignition timing ABASE corresponds to the reference value in the present invention.

When knocking occurs, the retardation correction amount AKNK is increased by a predetermined amount. That is, the ignition timing is delayed by a predetermined amount. The predetermined amount is determined in advance by an experiment or the like. The predetermined amount may be determined according to the strength of knocking. Note that, if the ignition timing is excessively delayed, misfires are caused. Therefore, the ignition timing when the retardation correction amount AKNK is applied is prevented from being retarded from the retardation guard value. That is, a limit is set for the retardation correction amount AKNK. As a result, the retardation correction amount AKNK becomes a value between 0 and the retardation guard value. This retard guard value is obtained in advance through experiments or the like as a value that can suppress misfire. In this embodiment, the retardation correction amount AK
The ECU 90 that calculates NK corresponds to the first correction means in the present invention.

And the ignition timing set in the operation area | region which does not introduce EGR gas is calculated | required by the following formula | equation. In this embodiment, it is assumed that the ignition timing becomes smaller as the retardation is retarded.
Ignition timing = reference ignition timing ABASE−retarding angle correction amount AKNK (1)
The retardation correction amount AKNK is a positive value. In this embodiment, the ignition timing calculated by the equation (1) corresponds to the second reference value in the present invention.

  Here, FIG. 2 is a diagram showing the ignition timing in the operation region where EGR is not introduced.

  Since the retard correction amount AKNK is a retard amount from the reference ignition timing ABASE, the finally set ignition timing is between the reference ignition timing ABASE and the retard guard value. That is, the ignition timing is set within the “AKNK range” in FIG.

  Next, the ignition timing in the operation region where EGR gas is introduced will be described. When knocking occurs in the operation region where EGR gas is introduced, the advance angle correction amount AEGR is corrected to the retard angle side. The advance angle correction amount AEGR is determined from the correction amount due to the introduction of EGR gas and the correction amount due to the occurrence of knocking. Here, the correction amount (hereinafter referred to as EGR introduction advance amount AEGRB) by introducing the EGR gas is determined by, for example, the operating state (for example, the engine speed and the engine load) of the internal combustion engine 1. This relationship is obtained in advance by experiments or the like and stored in the ECU 90. The advance angle amount AEGRB at the time of EGR introduction is a positive value. Further, the correction amount AEGRKNK according to the presence or absence of occurrence of knocking is decreased by a predetermined amount when knocking occurs, and is increased by a predetermined amount when knocking does not occur. That is, the correction amount AEGRKNK based on the presence or absence of occurrence of knocking increases the ignition timing as the value increases, and retards the ignition timing as the value decreases. The correction amount AEGRKNK depending on whether knocking has occurred can be a negative value.

That is, the advance angle correction amount AEGR is set by the following equation.
Advance angle correction amount AEGR = EGR angle advance angle amount AEGRB + correction amount AEGRKNK

And the ignition timing in the operation area | region which introduce | transduces EGR gas is calculated | required by the following formula | equation.
Ignition timing = reference ignition timing ABASE−retard angle correction amount AKNK + (advance angle amount AEGRB + correction amount AEGRKNK when EGR is introduced) Equation (2)

  That is, in the operation region where the EGR gas is introduced, the retardation correction amount AKNK obtained in the operation region where the EGR gas is not introduced is used as it is. In the operation region where EGR gas is introduced, the retardation correction amount AKNK is handled as a fixed value without being changed. By doing in this way, it can suppress that an ignition timing is corrected too much at the time of a transition. In this embodiment, the ECU 90 that calculates the EGR introduction advance amount AEGRB to be added to (reference ignition timing ABASE−retard angle correction amount AKNK) corresponds to the second correction means in the present invention. In this embodiment, the ECU 90 that calculates the correction amount AEGRKNK to be added to (reference ignition timing ABASE−retard angle correction amount AKNK + EGR introduction advance amount AEGRB) corresponds to the third correction means in the present invention. Further, in this embodiment, (reference ignition timing ABASE−retard angle correction amount AKNK + EGR introduction advance angle amount AEGRB) corresponds to the third reference value in the present invention.

Further, even if knocking occurs in the operation region where the EGR gas is not introduced, knocking does not necessarily occur in the operation region where the EGR gas is introduced. Therefore, the retardation correction amount AKNK obtained in the operation region where EGR gas is not introduced may be too large in the operation region where EGR gas is introduced. Therefore, when knocking does not occur in the operation region where EGR is introduced, the ignition timing can be corrected at least in the range of the reference ignition timing ABASE + EGR introduction advance amount AEGRB. That is, a limit is set to the maximum value of the set ignition timing, and this limit is set to a value obtained by adding the EGR introduction advance amount AEGRB to the reference ignition timing ABASE. The ignition timing obtained by adding the EGR introduction advance amount AEGRB to the reference ignition timing ABASE is defined as an advance guard value.

  That is, the correction amount AEGRKNK has −AEGRB as a lower limit value and + AKNK as an upper limit value. Therefore, the relationship of -AEGRB ≦ AEGRKNK ≦ + AKNK is established.

  FIG. 3 is a diagram showing the ignition timing in the operation region in which EGR is introduced.

  From the ignition timing delayed by the retard correction amount AKNK from the reference ignition timing ABASE, the advance angle is advanced by the EGR introduction advance amount AEGRB. Based on this ignition timing, a correction amount AEGRKNK is added according to whether knocking has occurred.

  FIG. 4 is a flowchart showing a flow for calculating the ignition timing according to the present embodiment. This routine is repeatedly executed every predetermined time.

  In step S101, it is determined whether or not it is an operation region where EGR gas is introduced. That is, it is determined whether or not EGR gas is introduced. Since the calculation method of the ignition timing changes depending on whether or not EGR gas is introduced, whether or not EGR gas is introduced is determined.

  If an affirmative determination is made in step S101, the process proceeds to step S102, and if a negative determination is made, the process proceeds to step S109.

  In step S102, the advance angle amount AEGRB at the time of EGR introduction, the correction amount AEGRKNK, and the retardation correction amount AKNK are read. These values are values stored in the ECU 90.

  In step S103, it is determined whether knocking has occurred. If an affirmative determination is made in step S103, the process proceeds to step S104, and if a negative determination is made, the process proceeds to step S105.

  In step S104, the correction amount AEGRKNK is decreased. At this time, it may be reduced by a preset amount or may be reduced by an amount corresponding to the strength of knocking.

  In step S105, the correction amount AEGRKNK is increased. At this time, it is increased by a preset amount.

  In step S106, an upper limit guard and a lower limit guard are applied to the correction amount AEGRKNK. That is, if the value after subtraction in step S104 is smaller than -AEGRB, -AEGRB is substituted for the correction amount AEGRKNK. If the value after the addition in step S105 is larger than AKNK, AKNK is substituted into the correction amount AEGRKNK. That is, the ignition timing is limited to be between the retard angle guard value and the advance angle guard value.

  In step S107, the finally set ignition timing is calculated. That is, the ignition timing is calculated by the equation (2).

  In step S108, the correction amount AEGRKNK is stored.

  In step S109, the retard correction amount AKNK is read. This value is the value at the previous routine.

  In step S110, it is determined whether knocking has occurred. If an affirmative determination is made in step S110, the process proceeds to step S111, and if a negative determination is made, the process proceeds to step S112.

  In step S111, the retard correction amount AKNK is increased. At this time, it may be increased by a preset amount, or may be increased by an amount corresponding to the strength of knocking.

  In step S112, the retardation correction amount AKNK is decreased. At this time, it is reduced by a preset amount.

  In step S113, an upper limit guard and a lower limit guard are applied to the retardation correction amount AKNK. That is, if the value after subtraction in step S112 is smaller than 0, 0 is substituted for the retardation correction amount AKNK. If the value after addition in step S111 is larger than the retard guard value, the retard guard value is substituted into the retard correction amount AKNK. This retardation guard value is an optimum value obtained in advance through experiments or the like.

  In step S114, the finally set ignition timing is calculated. That is, the ignition timing is calculated by the equation (1).

  In step S115, the retard correction amount AKNK is stored.

  By performing the processing described above, the ignition timing can be set.

  Here, the transition of the ignition timing at the transition time when the introduction of the EGR gas is stopped from the state where the EGR gas is introduced will be described. FIG. 5 is a time chart showing the transition of the opening degree of the EGR valve 32 and the ignition timing during a transition when the introduction of the EGR gas is stopped from the state where the EGR gas is introduced. The solid line in the ignition timing indicates the ignition timing that is finally set, the two-dot difference line indicates the ignition timing that is advanced from the reference ignition timing ABASE by the EGR introduction advance amount AEGRB, and the one-dot chain line indicates the reference ignition timing ABASE. The ignition timing is advanced by the advance amount AEGRB when EGR is introduced and further retarded by the correction amount AEGRKNK.

  The EGR valve 32 is initially fully opened (opening degree is 100%), starts to close from the time indicated by A, and is fully closed (opening degree is 0%) at the time indicated by B. Since EGR gas is introduced from before the time indicated by A to the time indicated by B, the ignition timing is calculated by equation (2). Further, the ignition timing after the time indicated by B is calculated by equation (1).

In the period from C to B, the advance amount AEGRB at the time of EGR introduction decreases with time, and unless the lower limit guard is applied to the correction amount AEGRKNK, the ignition timing is retarded from the retard guard value ( (See broken line in FIG. 5). Then, at the time B, the ignition timing is retarded from the ignition timing calculated by the equation (1). That is, at the time B, although the ignition timing calculated by the equation (1) is an appropriate value, the ignition timing is set to the retard side. Then, from the ignition timing calculated by Equation (2) at time B, Equation (1
), The ignition timing is rapidly changed to the calculated ignition timing. On the other hand, in this embodiment, by applying a lower limit guard to the correction amount AEGRKNK, the ignition timing does not become smaller than the value obtained by retarding the retardation correction amount AKNK from the reference ignition timing ABASE. Therefore, the ignition timing is constant during the period from C to B (see the solid line in FIG. 5).

  In this way, in the present embodiment, the ignition timing in B is equal to the value calculated by the equation (1) and the value calculated by the equation (2), so the ignition timing is switched smoothly. Thereby, since it can suppress that ignition timing is advanced or retarded excessively, it can suppress that misfire and knocking generate | occur | produce.

  In this embodiment, the ignition timing is corrected by adding or subtracting the correction amount, but it may be corrected by multiplying by a coefficient.

  FIG. 6 is a flowchart showing a flow of calculating the ignition timing according to the present embodiment by multiplying the correction coefficient. This routine is repeatedly executed every predetermined time.

  In step S201, it is determined whether or not it is an operation region where EGR gas is introduced. That is, it is determined whether or not EGR gas is introduced. That is, since the calculation method of the ignition timing varies depending on whether or not EGR gas is introduced, whether or not EGR gas is introduced is determined.

  If an affirmative determination is made in step S201, the process proceeds to step S202, and if a negative determination is made, the process proceeds to step S209.

  In step S202, the EGR introduction advance amount AEGRB, the correction coefficient AKEGR, and the retard correction amount are read. These values are values stored in the ECU 90. The correction coefficient AKEGR is a value used for correction by multiplying the advance angle amount AEGRB at the time of EGR introduction.

  In step S203, it is determined whether knocking has occurred. If an affirmative determination is made in step S203, the process proceeds to step S204, and if a negative determination is made, the process proceeds to step S205.

  In step S204, the correction coefficient AKEGR is decreased. At this time, it may be reduced by a preset amount or may be reduced by an amount corresponding to the strength of knocking.

  In step S205, the correction coefficient AKEGR is increased. At this time, it is increased by a preset amount.

  In this embodiment, the ECU 90 that processes step S204 or step S205 also corresponds to the third correction means in the present invention.

  In step S206, an upper limit guard and a lower limit guard are applied to the value obtained by multiplying the EGR introduction time advance amount AEGRB by the correction coefficient AKEGR. That is, when AKEGR × AEGRB is smaller than 0, 0 is substituted into AKEGR × AEGRB. When AKEGR × AEGRB is larger than AEGRB + AKNK, AEGRB + AKNK is substituted into AKEGR × AEGRB.

In step S207, the finally set ignition timing is calculated. That is, the ignition timing is calculated by the following equation.
Ignition timing = ABASE-AKNK + AKEGR x AEGRB

  In step S208, the correction coefficient AKEGR is stored.

  After step S209, the same processing as step S109 and subsequent steps in FIG.

  Thus, the ignition timing can also be set using the correction coefficient.

  As described above, according to the present embodiment, the retard correction amount AKNK obtained in the operation state in which the EGR gas is not introduced is treated as a fixed value in the operation state in which the EGR gas is introduced. Can be prevented from being advanced or retarded excessively. In addition, by setting a limit on the corrected ignition timing, it is possible to prevent the ignition timing from being advanced or retarded excessively. Thus, the occurrence of misfire or knocking can be suppressed.

It is a figure which shows schematic structure of the internal combustion engine which applies the control apparatus of the internal combustion engine which concerns on an Example, its intake system, and an exhaust system. It is the figure which showed the ignition timing in the driving | running | working area | region which does not introduce EGR. It is the figure which showed the ignition timing in the driving | running | working area | region which introduces EGR. It is the flowchart which showed the flow which calculates the ignition timing which concerns on an Example. It is the time chart which showed transition of the opening degree and ignition timing of the EGR valve at the time of transition when stopping the introduction of the EGR gas from the state where the EGR gas is introduced. It is the flowchart which showed the flow which calculates the ignition timing which concerns on an Example by multiplication of a correction coefficient.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Cylinder 3 Intake port 4 Intake pipe 5 Intake valve 6 Intake side cam 7 Exhaust port 8 Exhaust pipe 10 Exhaust valve 10 Cylinder head 11 Exhaust side cam 13 Crankshaft 14 Connecting rod 15 Piston 16 Intake throttle valve 30 EGR device 31 EGR Passage 32 EGR valve 81 Fuel injection valve 82 Spark plug 90 ECU
91 Accelerator opening sensor 92 Crank position sensor 94 Knock sensor 95 Air flow meter

Claims (2)

In a control device for an internal combustion engine comprising: an EGR device that reintroduces part of the exhaust gas of the internal combustion engine into the cylinder; and an ignition plug that generates an electric spark in the cylinder.
First correction means for calculating a retard amount from a reference value of the ignition timing when the ignition timing is retarded when knocking occurs in an operation region in which EGR gas is not introduced;
When the ignition timing is advanced according to the amount of EGR gas in the operation region where EGR gas is introduced, the ignition timing obtained by retarding the retardation amount calculated by the first correction means from the reference value is set to a second value. Second correction means for calculating a lead angle amount from the second reference value according to an EGR gas amount as a reference value;
When the ignition timing is retarded when knocking occurs in the operation region where EGR gas is introduced, the ignition timing obtained by advancing the advance amount calculated by the second correction means from the second reference value is set. Third correction means for calculating a retardation amount from the third reference value as a third reference value;
A control device for an internal combustion engine, comprising:   The third correction means calculates a retard amount of the ignition timing when knocking occurs in the operation region where EGR gas is introduced, and calculates an advance amount of the ignition timing when knocking does not occur. The limit of the retard amount from the third reference value is the same as the advance amount calculated by the second correction unit, and the limit of the advance amount is the retard amount calculated by the first correction unit. 2. The control device for an internal combustion engine according to claim 1, wherein the control devices have the same size.

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