JP6156125B2 - Control device for internal combustion engine - Google Patents

Description

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

  In a vehicle equipped with an internal combustion engine, when the accelerator operation amount by the driver decreases to “0” during deceleration, the intake air amount of the internal combustion engine is reduced to the target intake air amount for setting the engine rotation speed to the idle rotation speed. The Due to the reduction of the intake air amount, the torque of the internal combustion engine is reduced and the engine speed is adjusted to the idle speed. However, since there is a response delay in reducing the intake air amount of the internal combustion engine to the target intake air amount, excess air is sucked into the internal combustion engine due to the response delay. As a result, extra torque is generated in the internal combustion engine, thereby causing a delay in the torque reduction of the internal combustion engine for adjusting the engine rotational speed to the idle rotational speed. Therefore, as shown in Patent Document 1, it is conceivable to suppress the generation of the excessive torque in the engine by retarding the ignition timing of the internal combustion engine.

JP-A-2-123279

  By the way, when there is a response delay in the reduction of the intake air amount of the internal combustion engine to the target intake air amount, and the intake air amount greatly deviates from the target intake air amount, the internal combustion engine is In order to suppress the excessive torque generation of the engine, it is necessary to increase the retard amount of the ignition timing and greatly reduce the torque of the engine. However, in this case, the difference between the torque before execution of the retard of the ignition timing and the torque after execution becomes large, and drivability may be lowered.

  An object of the present invention is that drivability is reduced due to the retard of the ignition timing of the internal combustion engine when the engine speed is adjusted to the idle speed based on the accelerator operation amount being reduced to “0”. An object of the present invention is to provide a control device for an internal combustion engine that can be suppressed.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
A control device for an internal combustion engine that solves the above problem reduces the intake air amount of the internal combustion engine to a target intake air amount that sets the engine rotation speed to an idle rotation speed based on the fact that the accelerator operation amount has decreased to "0". . In addition, when an excessive torque is generated in the internal combustion engine due to a response delay in the reduction of the intake air amount, the control device for the internal combustion engine executes a retard control of the ignition timing of the engine to suppress the excessive torque. Is possible. When the amount of intake air of the internal combustion engine is reduced to the target intake air amount based on the reduction of the accelerator operation amount to “0”, the control device converges the intake air amount of the internal combustion engine with respect to the target intake air amount. Until the specified level is reached, the retard control of the ignition timing of the engine is not executed. The control device calculates a target throttle opening required to make the intake air amount of the internal combustion engine the target intake air amount, and drives the throttle valve based on the target throttle opening. Further, the actual throttle opening is calculated, and the convergence destination estimated air amount is estimated as the intake air amount when it is assumed that the internal combustion engine is normally operated at the actual throttle opening at the time of the calculation. An air amount estimation process for estimating a current estimated air amount as an actual intake air amount at the time of throttle opening calculation, and a convergence destination estimated air amount is less than a value obtained by adding a first predetermined value to a target intake air amount; and When the current estimated air amount is less than the value obtained by adding the second predetermined value to the convergence destination estimated air amount, the retardation permission is determined to determine that the convergence of the intake air amount of the internal combustion engine with respect to the target intake air amount has reached a specified level. And a determination process. Then, after the convergence of the intake air amount of the internal combustion engine with respect to the target intake air amount reaches a specified level, the retard control of the ignition timing of the internal combustion engine is executed.

  Thus, in a state where the convergence of the intake air amount of the internal combustion engine with respect to the target intake air amount reaches a specified level, the excessive torque in the internal combustion engine becomes small. Therefore, in order to suppress the excessive torque, the delay is performed. There is no need to significantly reduce the torque of the internal combustion engine through angular control. Therefore, it is possible to suppress an increase in torque fluctuation of the internal combustion engine when the ignition timing is retarded through the retard angle control, and thus it is possible to suppress a drivability decrease due to the torque fluctuation.

1 is a schematic diagram showing the overall configuration of a control device for an internal combustion engine. The block diagram which shows the outline | summary of the process performed through an electronic controller in the case of intake air amount control and ignition timing control of an internal combustion engine. (A)-(e) is a time chart which shows the change of the accelerator operation amount at the time of deceleration of a vehicle, the torque of an internal combustion engine, the amount of intake air, throttle opening, and ignition timing. The flowchart which shows the procedure which permits the retard angle control of the ignition timing in an internal combustion engine.

Hereinafter, an embodiment of a control device for an internal combustion engine will be described with reference to FIGS.
An internal combustion engine 1 shown in FIG. 1 is mounted on a vehicle such as an automobile. In the internal combustion engine 1, a throttle valve 13 is provided in an intake passage 3 connected to the combustion chamber 2 so as to be openable and closable. Air is sucked into the combustion chamber 2 through the intake passage 3, and from the fuel injection valve 4 to the engine. The fuel injected toward one intake port 3 a is supplied to the combustion chamber 2. When the air / fuel mixture is ignited by the spark plug 5, the air / fuel mixture burns, the piston 6 reciprocates, and the crankshaft 7 that is the output shaft of the internal combustion engine 1 rotates. On the other hand, the air-fuel mixture after burning in the combustion chamber 2 is sent to the exhaust passage 8 as exhaust gas.

  A vehicle on which the internal combustion engine 1 is mounted is provided with an electronic control device 51 that executes various controls relating to the operation of the engine 1. The electronic control unit 51 includes a CPU that executes various arithmetic processes related to the above control, a ROM that stores programs and data necessary for the control, a RAM that temporarily stores CPU calculation results, and the like. Input / output ports for inputting / outputting signals are provided.

Various sensors shown below are connected to the input port of the electronic control unit 51.
An air flow meter 52 that detects the amount of air passing through the intake passage 3 (intake air amount).
A crank position sensor 54 that outputs a signal corresponding to the rotation of the crankshaft 7.

A throttle position sensor 55 that detects the opening (throttle opening) of the throttle valve 13 provided in the intake passage 3.
An accelerator position sensor 57 that detects the amount of depression (accelerator operation amount) of the accelerator pedal 56 that is depressed by the driver of the vehicle.

  Connected to the output port of the electronic control unit 51 are drive circuits for various devices related to the operation of the internal combustion engine 1, such as a drive circuit for the fuel injection valve 4, a drive circuit for the spark plug 5, and a drive circuit for the throttle valve 13. .

  Then, the electronic control unit 51 grasps the current engine operating state and the required engine operating state based on the detection signals input from the various sensors, and various types connected to the output port based on the grasped engine operating state. A command signal is output to the drive circuit. Thus, intake air amount control, fuel injection amount control, ignition timing control, and the like in the internal combustion engine 1 are performed through the electronic control unit 51.

  In the fuel injection amount control of the internal combustion engine 1, the fuel injection valve 4 is driven such that an amount of fuel corresponding to the intake air amount of the engine 1 is injected from the fuel injection valve 4. For this reason, the amount of the air-fuel mixture supplied to the combustion chamber 2 is adjusted through the adjustment of the intake air amount of the internal combustion engine 1, and the torque of the internal combustion engine 1 is adjusted accordingly. In the intake air amount control of the internal combustion engine 1, the target intake air amount of the internal combustion engine 1 is set based on the accelerator operation amount and the like, and the throttle valve 13 is driven to realize the target intake air amount. Further, in the ignition timing control of the internal combustion engine 1, the ignition timing of the engine 1 is adjusted so that ignition is performed at the target ignition timing. It should be noted that the target ignition timing is normally the time when the torque of the engine 1 is maximized (MBT ignition timing) under the engine operating state in which the throttle valve 13 is driven to achieve the target intake air amount. Is set.

Next, details of intake air amount control and ignition timing control of the internal combustion engine 1 will be described.
FIG. 2 is a block diagram showing an outline of processing performed through the electronic control unit 51 during intake air amount control and ignition timing control of the internal combustion engine 1.

  The electronic control unit 51 determines the target torque Tt of the engine 1 based on various torque requests for the internal combustion engine 1 through the torque arbitration process S1. Examples of the various torque requests include a driver request torque based on the accelerator operation amount, an ISC target torque for adjusting the engine speed to the idle speed when the internal combustion engine 1 is idling, and the like. The engine speed is obtained based on a detection signal from the crank position sensor 54. The ISC target torque is a value obtained through the ISC control required torque calculation process S2 by the electronic control unit 51. In this ISC control request torque calculation process S2, the above-mentioned torque of the internal combustion engine 1 for adjusting the engine rotational speed to a predetermined idle rotational speed during idle operation of the internal combustion engine 1 at which the accelerator operation amount is “0”. The ISC target torque is calculated based on the rotational speed difference between the engine rotational speed and the idle rotational speed.

  In the torque adjustment process S1, the target torque Tt of the internal combustion engine 1 is set based on the driver request torque or the like when the accelerator operation amount is greater than “0”, while the ISC target torque is set as the target when the accelerator operation amount is “0”. Set to torque Tt. Subsequently, the electronic control unit 51 calculates a target intake air amount Gat in the internal combustion engine 1 based on the target torque Tt through an air amount conversion process S3. This target intake air amount Gat is a value corresponding to the intake air amount of the internal combustion engine necessary for setting the torque of the internal combustion engine 1 to the target torque Tt. Further, the electronic control unit 51 calculates a target throttle opening degree TAt in the internal combustion engine 1 based on the target intake air amount Gat through the throttle opening degree conversion process S4. This target throttle opening degree TAt is a value corresponding to the throttle opening degree necessary for setting the intake air amount of the internal combustion engine to the target intake air amount Gat.

  The electronic control unit 51 drives the throttle valve 13 based on the target throttle opening degree TAt so that the target throttle opening degree TAt is realized through the throttle driving process S5. By driving the throttle valve 13, the intake air amount of the engine 1 is adjusted to the target intake air amount Gat so that the torque of the internal combustion engine 1 becomes equal to the target torque Tt. Then, by adjusting the intake air amount in the internal combustion engine 1, the torque of the engine 1 is adjusted to the target torque Tt, whereby various torque requirements for the internal combustion engine 1 are satisfied.

  On the other hand, the electronic control unit 51 calculates the target ignition timing SAt based on the target torque Tt through the target ignition timing calculation process S6, and ignites the spark plug 5 at the target ignition timing SAt. The target ignition timing SAt calculated through the target ignition timing calculation process S6 is normally set so that the opening of the throttle valve 13 is the target throttle opening TAt so that the intake air amount of the internal combustion engine 1 matches the target intake air amount Gat. In such a situation, the ignition timing of the internal combustion engine 1 is set to a value that makes the MBT ignition timing.

  By the way, during the idling operation of the internal combustion engine 1 in which the accelerator operation amount is “0”, the above-described ISC target torque is set as the target torque Tt of the internal combustion engine 1. For this reason, in a situation where the driver reduces the accelerator operation amount to “0” while the vehicle is traveling, the target torque Tt is changed from the value set based on the driver request torque or the like to the ISC target torque described above. Is done. In this case, the target torque Tt is significantly reduced, and the target intake air amount Gat is also significantly reduced. Further, in order to reduce the intake air amount of the internal combustion engine 1 in accordance with the target intake air amount Gat, the throttle opening is rapidly reduced based on the decreasing target intake air amount Gat.

  However, even if the throttle opening is rapidly reduced in this way, it is inevitable that a response delay occurs in the reduction of the intake air amount of the internal combustion engine 1 with respect to the target intake air amount Gat that decreases as described above. . For this reason, excess air is sucked into the internal combustion engine 1 due to the response delay of the reduction in the intake air amount, and accordingly, excessive torque is generated in the internal combustion engine 1. The extra torque generation in the internal combustion engine 1 causes a delay in the torque reduction of the internal combustion engine 1 for adjusting the engine rotational speed to the idle rotational speed. In order to suppress such a delay in torque reduction, it is conceivable to retard the ignition timing of the internal combustion engine 1, but in order to determine whether or not the retard control of the ignition timing should be permitted, the electronic control unit 51 is used. Through this, an air amount estimation process S7 and a retard permission determination process S8 are performed.

  Specifically, the electronic control unit 51 obtains the actual throttle opening based on the detection signal from the throttle position sensor 55, and based on the actual throttle opening, through the air amount estimation processing S7, the convergence destination estimated air amount Ga1 and the current estimation. The air amount Ga2 is calculated. The convergence destination estimated air amount Ga1 is an estimated value of the intake air amount when it is assumed that the internal combustion engine 1 is normally operated at the calculated throttle opening in the transition period of the throttle opening change. The current estimated air amount Ga2 is an estimated value of the actual intake air amount at the time of calculation in the transition period of the throttle opening change. Further, the electronic control unit 51 determines the ignition timing for suppressing the delay of the torque reduction based on the convergence destination estimated air amount Ga1 and the current estimated air amount Ga2, and the target intake air amount Gat and the ISC target torque. It is determined whether or not the retard control should be permitted through the retard permission determination process S8.

  When it is determined through the retard permission determination process S8 that the ignition timing retard control for suppressing the delay in the torque reduction is to be permitted, the ignition timing retard control is performed based on the determination to that effect. Executed. Specifically, the target ignition timing SAt calculated in the target ignition timing calculation process S6 is retarded, and thereby the ignition timing of the internal combustion engine 1 is retarded to suppress the delay in torque reduction.

Next, the retard angle control of the ignition timing of the internal combustion engine 1 for suppressing the delay in torque reduction will be described in more detail.
3A to 3E show changes in the accelerator operation amount, the torque of the internal combustion engine 1, the intake air amount, the throttle opening, and the ignition timing when the traveling vehicle is decelerated. When the driver decelerates the accelerator operation amount to “0” as shown in FIG. 3 (a) (timing t1), the target torque Tt becomes as shown by the solid line in FIG. 3 (b). By changing the setting to the ISC target torque, the target torque Tt significantly decreases before and after the accelerator operation amount decreases to “0”. As the target torque Tt decreases significantly, the target intake air amount Gat also decreases significantly as shown by the solid line in FIG. Further, as the target intake air amount Gat significantly decreases, the throttle opening rapidly decreases as shown in FIG.

  Even if the throttle opening is rapidly reduced in this way, the response to the reduction of the intake air amount of the internal combustion engine 1 is responsive to the target intake air amount Gat that significantly decreases as shown by the solid line in FIG. There is a delay. In relation to such a response delay in the reduction of the intake air amount, the convergence destination estimated air amount Ga1 changes as shown by a broken line in FIG. 3C, and as shown by a two-dot chain line in FIG. The estimated air amount Ga2 changes. Then, excess air is sucked into the internal combustion engine 1 due to the response delay of the intake air amount, and accordingly, excessive torque is generated in the internal combustion engine 1. Then, due to the generation of the extra torque in the internal combustion engine 1, there is a delay in the decrease in the torque of the internal combustion engine 1 for adjusting the engine rotational speed to the idle rotational speed, that is, the decrease in the actual torque of the internal combustion engine toward the target torque Tt. Arise. Therefore, the actual torque of the internal combustion engine 1 decreases only slowly as shown by the broken line in FIG. 3B, whereas the target torque Tt decreases by the solid line in FIG.

  In order to suppress such a delay in torque reduction of the internal combustion engine 1, it is conceivable to retard the ignition timing of the internal combustion engine 1. Here, when a delay in the torque reduction occurs, the target torque Tt is significantly changed as described above by changing the setting to the ISC target torque. Therefore, the target torque Tt (corresponding to the ISC target torque) at this time is the internal combustion engine when the intake air amount is converged to the target intake air amount Gat in the internal combustion engine 1 and ignition is performed at the MBT ignition timing. It becomes less than the torque of the engine 1 (hereinafter referred to as ISC target MBT torque). For this reason, based on the fact that the target torque Tt is less than the ISC target MBT torque, the delay control of the ignition timing of the internal combustion engine 1 is permitted in order to suppress the response delay in a situation where the response delay of the torque reduction occurs. It can be determined that the situation should be, and it is conceivable to retard the ignition timing when the determination is made.

  When permitting retarding control of the ignition timing under such conditions, the timing at which the accelerator operation amount becomes “0” and the target torque Tt (ISC target torque) becomes less than the ISC target MBT torque, that is, target intake air. The ignition timing is retarded at a timing when the intake air amount of the internal combustion engine 1 greatly deviates toward the increase side with respect to the amount Gat. In this case, if an attempt is made to suppress the generation of excess torque in the engine 1 due to a delay in response to the reduction of the intake air amount in the internal combustion engine 1 due to the retard of the ignition timing, the ignition is performed as shown by a broken line in FIG. It is necessary to greatly reduce the torque of the internal combustion engine 1 by increasing the timing retardation amount. If the retard amount of the ignition timing is increased in this way, the actual torque of the internal combustion engine 1 can be quickly reduced in accordance with the target torque Tt that decreases as shown by the solid line in FIG.

However, in this case, the difference between the torque before execution of the ignition timing retardation and the torque after execution becomes large, which may cause a decrease in drivability.
In order to cope with such a problem, the retard control of the ignition timing in the internal combustion engine 1 is executed as follows. That is, when the intake air amount of the internal combustion engine 1 is reduced to the target intake air amount Gat based on the decrease in the accelerator operation amount to “0”, the intake air amount of the internal combustion engine 1 with respect to the target intake air amount Gat is reduced. Until the convergence reaches a specified level, the control is not executed by not permitting the retard control of the ignition timing in the engine 1. Then, when the convergence of the intake air amount of the internal combustion engine 1 with respect to the target intake air amount Gat reaches a specified level, the retard control of the ignition timing is permitted, whereby the intake air of the internal combustion engine 1 with respect to the target intake air amount Gat. The retard control of the ignition timing is executed after the convergence of the quantity reaches a specified level.

  When the intake air amount of the internal combustion engine 1 is reduced to the target intake air amount Gat based on the decrease in the accelerator operation amount to “0”, the convergence of the intake air amount of the internal combustion engine 1 with respect to the target intake air amount Gat is converged. The determination as to whether or not the specified level has been reached is made based on whether or not the following [Condition A] and [Condition B] are satisfied through the retard angle permission determination process S8.

[Condition A] The convergence destination estimated air amount Ga1 becomes less than a value obtained by adding a predetermined value OS1 to the target intake air amount Gat (“Gat + OS1”).
[Condition B] The current estimated air amount Ga2 becomes less than a value (“Ga1 + OS2”) obtained by adding a predetermined value OS2 to the convergence destination estimated air amount Ga1.

  Based on the establishment of both [Condition A] and [Condition B], it is determined that the convergence of the intake air amount of the internal combustion engine 1 with respect to the target intake air amount Gat has reached a specified level. On the other hand, if either [Condition A] or [Condition B] is not satisfied, it is determined that the convergence of the intake air amount of the internal combustion engine 1 with respect to the target intake air amount Gat has not reached the specified level.

  In the example of FIG. 3, [Condition A] is satisfied at timing t2 later than timing t1, and “Condition B” is also satisfied at timing t3. Therefore, at timing t3, it is determined that the convergence of the intake air amount of the internal combustion engine 1 with respect to the target intake air amount Gat has reached a specified level, and based on this determination, retarding control of the ignition timing is permitted. By permitting such retard control of the ignition timing, the retard of the ignition timing of the internal combustion engine 1 is started at a timing t3 that is later than the timing t1, as indicated by a solid line in FIG. During the process until the ignition timing delay is started and the intake air amount of the internal combustion engine 1 converges with respect to the target intake air amount Gat, the internal combustion engine 1 is controlled according to the reduction of the intake air amount. The actual torque gradually decreases as shown by the broken line in FIG. Therefore, at the timing t3, the extra torque generated in the internal combustion engine 1 due to the response delay in the reduction of the intake air amount is reduced. For this reason, it is not necessary to significantly reduce the torque of the internal combustion engine 1 by significantly retarding the ignition timing by the retardation control in order to suppress the excessive torque.

Next, the operation of the control device for the internal combustion engine 1 will be described.
FIG. 4 is a flowchart showing a retard control permission routine for permitting the retard control of the ignition timing in the internal combustion engine 1. This retardation control permission routine is periodically executed by a time interruption every predetermined time through the retardation permission determination processing S8 in the electronic control unit 51.

  The electronic control unit 51 proceeds to S102 based on an affirmative determination in step 101 (S101) of the routine, that is, a determination that the retard control is not permitted. The electronic control unit 51 determines whether or not the target torque Tt is less than the ISC target MBT torque (hereinafter referred to as torque idle state) as the process of S102. In this torque idle state, when the accelerator operation amount is reduced to “0” in order to decelerate the running vehicle, a delay occurs in the torque reduction of the internal combustion engine 1 for adjusting the engine rotational speed to the idle rotational speed. This occurs when the target torque Tt (corresponding to the ISC target torque) is reduced in order to promptly reduce the engine speed to the idle speed. Then, when the target torque Tt thus reduced becomes less than the ISC target MBT torque, it is determined in S102 that the engine is in the torque idle state.

  Therefore, when it is determined in S102 that the torque idle state is not established, it means that the response delay of the torque reduction is not caused. In this case, the process proceeds to S106. The electronic control unit 51 does not allow the retard control of the ignition timing in the internal combustion engine 1 for suppressing the delay of the torque reduction as the process of S106, in other words, prohibits the execution of the retard control. . After executing the process of S106, the electronic control unit 51 once terminates the retard control permission routine. On the other hand, when it is determined in S102 that the engine is in the torque idle state, it means that the response delay of the torque reduction occurs. In this case, the process proceeds to S103.

  The processes of S103 and S104 are for determining whether or not the convergence has reached a specified level in the process in which the intake air amount of the internal combustion engine 1 converges with respect to the target intake air amount Gat. The electronic control unit 51 determines whether or not [Condition A] is satisfied as the processing of S103, that is, the convergence destination estimated air amount Ga1 is less than a value (“Gat + OS1”) obtained by adding the predetermined value OS1 to the target intake air amount Gat. It is determined whether or not. If a positive determination is made here, the process proceeds to S104. The electronic control unit 51 determines whether or not [Condition B] is satisfied as the process of S104, that is, the current estimated air amount Ga2 is less than the value obtained by adding the predetermined value OS2 to the convergence destination estimated air amount Ga1 (“Ga1 + OS2”). It is determined whether or not.

  If a negative determination is made in either of the processes of S103 and S104, the electronic control unit 51 determines that the convergence of the intake air amount of the internal combustion engine 1 with respect to the target intake air amount Gat has not reached a specified level. In this case, the process of S106 described above is executed. Further, when both the processing of S103 and the processing of S104 are positively determined, the electronic control unit 51 determines that the convergence of the intake air amount of the internal combustion engine 1 with respect to the target intake air amount Gat has reached a specified level. . In this case, the process proceeds to S105. The electronic control unit 51 permits the retard control of the ignition timing in the engine 1 to suppress the delay of the torque reduction as the process of S105, and then temporarily terminates the retard control permission routine.

  By permitting the retard control of the ignition timing in the process of S105, the ignition timing of the engine 1 is set to suppress the delay of the torque decrease in the internal combustion engine 1 for adjusting the engine speed to the idle speed. Be retarded. Thereby, it is suppressed that the torque fluctuation of the internal combustion engine 1 due to execution of the retard of the ignition timing becomes large and the drivability is lowered. This is because, at the timing at which the retard of the ignition timing is started, the extra torque generated in the engine 1 due to the response delay of the reduction in the intake air amount of the internal combustion engine 1 with respect to the target intake air amount Gat is small. This is related to the fact that the retard amount of the ignition timing for suppressing the excessive torque is small. Since the retard amount of the ignition timing is small, the torque of the internal combustion engine is not greatly reduced by the retard amount of the ignition timing corresponding to the retard amount, and the torque fluctuation at that time increases. There is nothing. As a result, a decrease in drivability is suppressed as described above.

  If the retard control of the ignition timing in the internal combustion engine 1 is permitted by the process of S105, a negative determination is made in the subsequent process of S101, and the process proceeds to S107. The electronic control unit 51 determines whether or not the engine is in a torque idle state as a process of S107, in other words, whether or not the torque idle state continues after execution of retarding the ignition timing based on permission of the retardation control. If the determination is affirmative, the routine proceeds to S105, where the above retard control is continuously permitted, and the retard of the ignition timing based on the permit is also continued. On the other hand, if the intake air amount of the internal combustion engine 1 converges with respect to the target intake air amount Gat while the retard of the ignition timing continues, the engine speed is reduced due to the torque reduction of the engine 1 due to the retard of the ignition timing. Becomes less than the idle rotation speed, the target torque Tt (ISC target torque) increases. If the ISC target torque is equal to or greater than the ISC target MBT torque, a negative determination is made in the process of S107, and the process proceeds to S106. In this case, execution of the retard control is prohibited and the retard of the ignition timing is terminated.

According to the embodiment described in detail above, the following effects can be obtained.
(1) When the accelerator operation amount is reduced to “0” when the traveling vehicle is decelerated, the intake air amount of the internal combustion engine 1 toward the target intake air amount Gat for adjusting the engine rotation speed to the idle rotation speed Response delay occurs in the weight loss. Further, with the response delay of the reduction of the intake air amount, a delay also occurs in the torque reduction of the internal combustion engine toward the target torque Tt (corresponding to the ISC target torque) for adjusting the engine rotational speed to the idle rotational speed. Then, the retard control of the ignition timing in the internal combustion engine 1 for suppressing the delay of the torque decrease is executed as follows. That is, until the convergence of the intake air amount of the internal combustion engine 1 with respect to the target intake air amount Gat reaches a specified level, the control is not executed by not permitting the retard control of the ignition timing in the engine 1. . Then, when the convergence of the intake air amount of the internal combustion engine 1 with respect to the target intake air amount Gat reaches a specified level, the retard control of the ignition timing is permitted, whereby the intake air of the internal combustion engine 1 with respect to the target intake air amount Gat. The retard control of the ignition timing is executed after the convergence of the quantity reaches a specified level. When ignition timing retard control is executed in this way, excess torque generated in the internal combustion engine 1 due to a response delay in reducing the intake air amount at the start of ignition timing retard by the retard control is generated. Get smaller. For this reason, in order to suppress the excessive torque, there is no need to greatly reduce the torque of the internal combustion engine 1 by increasing the retard amount of the ignition timing in the retard control. Accordingly, it is possible to suppress a decrease in drivability due to an increase in torque fluctuation of the internal combustion engine 1 when the ignition timing is retarded.

  (2) Since the ignition timing of the internal combustion engine 1 is retarded from the MBT ignition timing during execution of the retardation control, it cannot be denied that the fuel consumption of the internal combustion engine 1 deteriorates due to the retardation. However, the retard control is not permitted until the convergence of the intake air amount of the internal combustion engine 1 with respect to the target intake air amount Gat reaches a specified level, and delays the start timing of the retard of the ignition timing until the permission is granted. be able to. And by delaying the start timing of the retard of the ignition timing in this way, it is possible to suppress the deterioration of the fuel consumption of the internal combustion engine 1 due to the retard.

  (3) Whether the convergence of the intake air amount of the internal combustion engine 1 with respect to the target intake air amount Gat has reached a specified level is determined based on whether [Condition A] and [Condition B] are satisfied. The That is, based on the establishment of both [Condition A] and [Condition B], it is determined that the convergence of the intake air amount of the internal combustion engine 1 with respect to the target intake air amount Gat has reached a specified level. Therefore, when it is determined that the convergence of the intake air amount of the internal combustion engine 1 with respect to the target intake air amount Gat has reached a specified level, the determination can be made accurate.

  DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Combustion chamber, 3 ... Intake passage, 3a ... Intake port, 4 ... Fuel injection valve, 5 ... Spark plug, 6 ... Piston, 7 ... Crankshaft, 8 ... Exhaust passage, 13 ... Throttle valve, DESCRIPTION OF SYMBOLS 51 ... Electronic control unit, 52 ... Air flow meter, 54 ... Crank position sensor, 55 ... Throttle position sensor, 56 ... Accelerator pedal, 57 ... Accelerator position sensor

Claims (1)

Based on the fact that the accelerator operation amount has decreased to “0”, the intake air amount of the internal combustion engine is reduced to the target intake air amount with the engine speed set to the idle rotation speed, and this is due to a response delay in the reduction of the intake air amount. In a control device for an internal combustion engine that executes retarded control of ignition timing of the engine for suppressing excess torque of the internal combustion engine,
Calculating a target throttle opening required for the intake air amount of the internal combustion engine to be the target intake air amount, and driving a throttle valve based on the target throttle opening;
When the intake air amount of the internal combustion engine is reduced to the target intake air amount based on the reduction of the accelerator operation amount to “0”, the convergence of the intake air amount of the internal combustion engine with respect to the target intake air amount reaches a specified level. Until this, the retard control of the ignition timing of the engine is not executed ,
In addition to calculating the actual throttle opening, the convergence target estimated air amount is estimated as the intake air amount when it is assumed that the internal combustion engine is normally operated at the actual throttle opening at the time of the calculation, and the actual throttle opening An air amount estimation process for estimating the current estimated air amount as the actual intake air amount at the time of opening calculation;
The convergence destination estimated air amount is less than a value obtained by adding a first predetermined value to the target intake air amount, and the current estimated air amount is less than a value obtained by adding a second predetermined value to the convergence destination estimated air amount. A control device for an internal combustion engine that performs a retard permission determination process for determining that the convergence of the intake air amount of the internal combustion engine with respect to the target intake air amount has reached the specified level .