JP2019039310A - Control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress unstable combustion of an air-fuel mixture in each cylinder in a control device of an internal combustion engine capable of performing both dither control and sprung vibration damping control. SOLUTION: A control device 20 includes a dither control unit M80 in which a part of a plurality of cylinders is a rich combustion cylinder and a cylinder different from the rich combustion cylinder in each cylinder is a lean combustion cylinder. It is provided with an intake amount target value calculation unit M41 for calculating an intake amount target value. The intake amount target value calculation unit M41 calculates the intake amount target value so that the intake amount target value becomes larger when the dither control is performed than when the dither control is not performed. And the sprung vibration suppression control that corrects the intake amount target value according to the sprung vibration of the vehicle. Then, when either the dither control or the spring damping control is being controlled, the other control is prohibited or the other control is restricted. [Selection diagram] Fig. 2

Description

  The present invention relates to an internal combustion engine control apparatus applied to an internal combustion engine having a plurality of cylinders.

  Patent Document 1 describes an example of a control device for an internal combustion engine that raises the temperature of a catalyst provided in an exhaust passage by performing dither control. In the dither control, some of the plurality of cylinders are rich combustion cylinders in which the air-fuel ratio of the mixture is richer than the stoichiometric air-fuel ratio, and the remaining cylinders of the plurality of cylinders are the stoichiometric air-fuel ratio. Rather, the lean air-fuel ratio of the air-fuel mixture is lean. In the dither control, the fuel supply amount in each cylinder is adjusted so that the average value of the air-fuel ratio of the air-fuel mixture in all cylinders including the rich combustion cylinder and the lean combustion cylinder becomes the target air-fuel ratio. The When such dither control is performed, in the exhaust passage, unburned fuel components and incomplete combustion components contained in the exhaust discharged from the rich combustion cylinder are oxidized by oxygen contained in the exhaust discharged from the lean combustion cylinder. Is done. Thereby, the temperature of the catalyst can be raised.

  Note that when the dither control is performed, the output torque of the internal combustion engine is lower than before the dither control is performed. For this reason, when dither control is performed, in order to compensate for such a decrease in output torque, dither time correction control for increasing the throttle opening that is the throttle valve opening, that is, the intake air amount, is performed. There is. By performing such dither correction control together with dither control, it is possible to suppress a decrease in output torque of the internal combustion engine that accompanies the dither control.

  Further, while the vehicle is running, so-called sprung vibration, which is vibration on the vehicle body side of the vehicle suspension, may occur due to vehicle operation by the vehicle driver or input of disturbance to the vehicle. Patent Document 2 describes an example of a control device for an internal combustion engine that performs sprung mass damping control that suppresses such sprung vibration. In this sprung mass damping control, the sprung vibration is suppressed by correcting the output torque of the internal combustion engine in accordance with the sprung vibration. An example of a method of correcting the output torque of the internal combustion engine during the execution of sprung mass damping control is a method of adjusting the intake air amount.

JP 2004-218541 A Japanese Patent No. 5099231

  By the way, when both dither control and sprung mass damping control are performed, the correction of the intake air amount by the dither correction control performed together with the dither control and the correction of the intake air amount by the sprung mass damping control overlap. Will be. In this case, the correction of the two intake air amounts may interfere with each other, and the intake air amount may change suddenly. If the intake air amount changes abruptly in this way, the air-fuel ratio of the air-fuel mixture in each cylinder fluctuates, and the combustion of the air-fuel mixture in each cylinder may become unstable.

  An internal combustion engine control apparatus for solving the above-described problem is that a part of a plurality of cylinders of the internal combustion engine is a rich combustion cylinder in which the air-fuel ratio of the air-fuel mixture is richer than the stoichiometric air-fuel ratio. Dither control is performed to adjust the amount of fuel supplied to each cylinder so that a cylinder other than the rich combustion cylinder becomes a lean combustion cylinder in which the air-fuel ratio of the air-fuel mixture becomes leaner than the stoichiometric air-fuel ratio. A dither control unit that performs the above operation, and an intake air amount target value calculation unit that calculates an intake air amount target value that is a target value of the intake air amount. The intake air amount target value calculation unit calculates the same intake air amount target value so that the intake air amount target value becomes larger when the dither control is performed than when the dither control is not performed. And sprung mass damping control for correcting the intake air amount target value according to the sprung vibration of the vehicle. Then, when either one of the dither control and the sprung mass damping control is being performed, the control device prohibits the execution of the other control or places a restriction on the other control.

  According to the above configuration, when the dither control is performed, the intake air amount is increased by performing the dither correction control than when the dither control is not performed. Thus, the output torque of the internal combustion engine can be increased by increasing the intake air amount. That is, it is possible to compensate for a decrease in output torque accompanying the execution of dither control.

  Further, when the sprung mass damping control is performed, the intake air amount is corrected in accordance with the sprung mass vibration. Thereby, since the torque generated at the wheel is adjusted in accordance with the sprung vibration, the sprung vibration can be suppressed.

  In the above configuration, when any one of the dither control and the sprung mass damping control is performed, the execution of the other control is prohibited, or a restriction is provided on the other control. By prohibiting the execution of the other control, it is possible to prevent the correction of the intake air amount by the dither correction control performed together with the dither control and the correction of the intake air amount by the sprung mass damping control from interfering with each other. As a result, a sudden change in the intake air amount is suppressed. Therefore, fluctuations in the air-fuel ratio of the air-fuel mixture in each cylinder can be suppressed, and consequently the combustion of the air-fuel mixture in each cylinder can be suppressed from becoming unstable.

  In addition, by providing a restriction on the other control, it is possible to reduce the degree of interference between the correction of the intake air amount by the dither correction control performed together with the dither control and the correction of the intake air amount by the sprung mass damping control. it can. As a result, it is possible to suppress a sudden change in the intake air amount as compared with the case where no limitation is imposed on the other control. Therefore, fluctuations in the air-fuel ratio of the air-fuel mixture in each cylinder can be suppressed, and consequently the combustion of the air-fuel mixture in each cylinder can be suppressed from becoming unstable.

The block diagram which shows an internal combustion engine provided with the control apparatus which is 1st Embodiment of the control apparatus of an internal combustion engine, a transmission, and a wheel. The block diagram which shows the function structure of the control apparatus in the 1st Embodiment. The flowchart explaining the processing routine which a drive torque conversion part performs in the same 1st Embodiment. 9 is a flowchart for explaining a processing routine executed by a request value calculation unit in the first embodiment. The timing chart when the execution conditions of dither control are satisfied under the condition in which sprung mass damping control is performed in the first embodiment. The flowchart explaining the process routine which a drive torque conversion part performs in 2nd Embodiment. The flowchart explaining the process routine which a request value calculation part performs in the said 2nd Embodiment.

Hereinafter, an embodiment of a control device for an internal combustion engine will be described with reference to FIGS.
FIG. 1 illustrates an internal combustion engine 10 including the control device 20 of the present embodiment, a transmission 100 to which the output torque of the internal combustion engine 10 is input, and a wheel 101 to which the output torque of the transmission 100 is input. ing.

  As shown in FIG. 1, the internal combustion engine 10 includes a plurality (four in this embodiment) of cylinders # 1, # 2, # 3, and # 4 and combustion chambers 11 of the cylinders # 1 to # 4. An intake passage 12 through which air to be introduced flows and a fuel injection valve 13 of the same number as the number of cylinders are provided. The intake passage 12 is provided with a throttle valve 14 that operates to adjust the intake air amount GA. Each fuel injection valve 13 is driven to supply fuel to the combustion chamber 11.

  In each combustion chamber 11, an air-fuel mixture containing air introduced from the intake passage 12 and fuel supplied by driving the fuel injection valve 13 is combusted by spark discharge of the ignition device 15. The air-fuel mixture used for combustion is discharged from each combustion chamber 11 to the exhaust passage 16 as exhaust. The exhaust passage 16 is provided with a three-way catalyst 17 for purifying exhaust.

  Various controls related to the operation of the internal combustion engine 10 are performed by the control device 20. The control device 20 includes a CPU 21 that performs various engine controls, and a memory 22 that stores information necessary for the engine controls. Detection signals are input to the internal combustion engine 10 from various sensors such as an air-fuel ratio sensor SE1, a crank angle sensor SE2, an air flow meter SE3, an accelerator sensor SE4, and a wheel speed sensor SE5.

  The air-fuel ratio sensor SE1 is disposed upstream of the three-way catalyst 17 in the exhaust passage 16, and outputs a signal corresponding to the oxygen concentration of the exhaust gas flowing through the exhaust passage 16. The control device 20 calculates an air-fuel ratio detection value AF, which is an air-fuel ratio detection value, based on the detection signal from the air-fuel ratio sensor SE1.

  The crank angle sensor SE2 outputs a signal corresponding to the engine rotational speed NE that is the rotational speed of the engine output shaft. The air flow meter SE3 is provided in the intake passage 12 and outputs a signal corresponding to the intake air amount GA. The accelerator sensor SE4 outputs a signal corresponding to the accelerator operation amount ACCP that is the operation amount of the accelerator pedal.

  The wheel speed sensor SE5 outputs a signal corresponding to the rotation speed of the wheel 101. In the control device 20, the rotational speed of the wheel 101 is calculated based on the signal from the wheel speed sensor SE5, and the wheel speed VW is calculated based on the rotational speed and radius of the wheel 101.

  The controller 20 performs sprung mass damping control, dither control, and dither correction control as part of engine control. The sprung mass damping control is a control for correcting the output torque of the internal combustion engine 10 to suppress the sprung vibration of the vehicle. Dither control is control for increasing the temperature of the three-way catalyst 17 provided in the exhaust passage 16. The dither correction control is control for compensating for a decrease in output torque of the internal combustion engine 10 due to execution of dither control.

  Here, the sprung vibration refers to vibration generated in the vehicle body via the suspension due to the input of disturbance from the road surface to the wheel 101. This sprung vibration includes a component in the vehicle pitching direction or the vehicle vertical direction.

  As shown in FIG. 2, the control device 20 includes a required torque setting unit M10 and a sprung mass damping correction torque calculation unit M20 as functional units for performing sprung mass damping control, dither control, and dither correction control. A target air-fuel ratio setting unit M30, a throttle opening target value calculation unit M40, a throttle valve control unit M50, a base injection amount calculation unit M60, an air-fuel ratio control unit M70, a dither control unit M80, and an injection valve control unit M90. Yes.

<Required torque setting unit M10>
The required torque setting unit M10 includes a base required torque calculation unit M11 and a dither correction torque calculation unit M12. Base required torque calculation unit M11 calculates base required torque TrqB based on accelerator operation amount ACCP. The base required torque TrqB is the sum of the torque for the wheel 101 (driving wheel) determined according to the accelerator operation amount ACCP and the torque (load torque) for auxiliary equipment such as an alternator and an air conditioner compressor. Therefore, the base required torque calculation unit M11 calculates the base required torque TrqB by taking into account the operation amount of auxiliary equipment such as an alternator and a compressor.

  The dither correction torque calculation unit M12 calculates the dither torque correction amount TrqD based on the injection amount correction request value α calculated by the request value calculation unit M81 of the dither control unit M80 described later. The dither correction torque calculation unit M12 makes the dither torque correction amount TrqD equal to “0” when the injection amount correction request value α is equal to “0” (that is, when the dither control is not performed). On the other hand, when the injection amount correction request value α is larger than “0”, the dither correction torque calculation unit M12 corrects the dither torque so that the dither torque correction amount TrqD increases as the injection amount correction request value α increases. The amount TrqD is calculated.

  Further, the required torque setting unit M10 obtains the sum of the base required torque TrqB calculated by the base required torque calculating unit M11 and the dither torque correction amount TrqD calculated by the dither correction torque calculating unit M12 as the required torque Trq. Is provided as an adder M13. Further, the required torque setting unit M10 corrects the sum of the required torque Trq calculated by the adder M13 and the damping torque correction amount TrqS calculated by the sprung mass damping correction torque calculating unit M20. An adder M14 that calculates the required torque Trq is provided. That is, in the present embodiment, the required torque Trq can be calculated by correcting the base required torque TrqB with the dither torque correction amount TrqD and the damping torque correction amount TrqS.

<Spring-suppressed vibration correction torque calculation unit M20>
The sprung mass damping correction torque calculation unit M20 converts the required torque Trq calculated by the adder M13 of the required torque setting unit M10 into the required wheel torque WTrq0, which is a required value of the torque generated by the wheel 101 (drive wheel). A wheel torque conversion unit M21 for conversion is included. The wheel torque conversion unit M21 converts the required torque Trq into the required wheel torque WTrq0 in consideration of the gear ratio selected by the transmission 100.

  Further, the sprung mass damping correction torque calculation unit M20 calculates a wheel torque estimated value WTrqE that is an estimated value of the torque generated in the drive wheel based on the average value of the wheel speeds VW of the wheels 101. A torque estimation unit M22 is included. When a disturbance is input to the wheel 101, the wheel speed VW is changed by the input of the disturbance, so that the wheel torque estimated value WTrqE includes a disturbance component input to the wheel 101.

  Further, the sprung mass damping correction torque calculation unit M20 is provided with a vibration damping correction amount calculation unit M23 to which the requested wheel torque WTrq0 and the wheel torque estimated value WTrqE are input. The vibration suppression correction amount calculation unit M23 has a vehicle body motion model. Therefore, the vibration suppression correction amount calculation unit M23 can derive the vibration suppression wheel torque correction amount WTrq1, which is a correction amount of the required torque Trq with respect to the disturbance, based on the required wheel torque WTrq0 and the wheel torque estimated value WTrqE. .

  The sprung mass damping correction torque calculation unit M20 uses the vibration damping wheel torque correction amount WTrq1 derived by the vibration damping correction amount calculation unit M23 as the damping amount that is the correction amount of the output torque of the internal combustion engine 10. A drive torque conversion unit M24 that converts the torque correction amount TrqS for use is provided. The drive torque conversion unit M24 converts the vibration damping wheel torque correction amount WTrq1 into the vibration damping torque correction amount TrqS in consideration of the gear ratio selected by the transmission 100. Then, the drive torque conversion unit M24 outputs the derived damping torque correction amount TrqS to the adder M14 of the required torque setting unit M10.

The calculation of the damping torque correction amount TrqS for suppressing the sprung vibration is performed when a predetermined condition for the sprung damping control is satisfied. For example, the execution condition of sprung mass damping control includes the following three conditions.
(Condition 1-1) An air-fuel ratio feedback correction value (hereinafter referred to as “air-fuel ratio F / B” derived by air-fuel ratio feedback control (hereinafter referred to as “air-fuel ratio F / B control”) by an air-fuel ratio control unit M70 described later. It is called “correction value.”) The absolute value of FAF is less than the specified value.
(Condition 1-2) The learning of the air-fuel ratio is completed by the air-fuel ratio learning control by the air-fuel ratio control unit M70.
(Condition 1-3) The concentration of the purge gas is less than a predetermined value.

  When the condition for executing the sprung mass damping control is satisfied, the drive torque converting unit M24 derives the damping torque correction amount TrqS as described above, and uses the damping torque correction amount TrqS as the required torque. Output to the setting unit M10. Thereby, the required torque Trq is corrected by the damping torque correction amount TrqS. On the other hand, when the execution condition of the sprung mass damping control is not satisfied, the drive torque conversion unit M24 makes the damping torque correction amount TrqS equal to “0”, and this damping torque correction amount TrqS (= 0) ) Is output to the required torque setting unit M10. In this case, the required torque Trq is not corrected by the damping torque correction amount TrqS.

<Target air-fuel ratio setting unit M30>
The target air-fuel ratio setting unit M30 sets a target air-fuel ratio AFT that is a target value of the air-fuel ratio.
<Throttle opening target value calculation unit M40>
The throttle opening target value calculation unit M40 includes an intake air amount target value setting unit M41 that calculates an intake air amount target value GAT that is a target value of the intake air amount GA. The intake air amount target value setting unit M41 calculates the required torque Trq calculated by the adder M14 of the required torque setting unit M10, the target air-fuel ratio AFT set by the target air-fuel ratio setting unit M30, and the engine speed NE. Based on this, an intake air amount target value GAT is calculated. At this time, the intake air amount target value setting unit M41 calculates the intake air amount target value GAT so that the intake air amount target value GAT increases as the required torque Trq increases. Therefore, when the required torque Trq is increased and corrected by the dither torque correction amount TrqD, the intake air amount target value GAT increases as the dither torque correction amount TrqD increases. That is, when the injection amount correction request value α is larger than “0” because the dither control is performed, than when the injection amount correction request value α is equal to “0” because the dither control is not performed. As the dither torque correction amount TrqD is larger than “0”, the intake air amount target value GAT increases. Therefore, in the present embodiment, the calculation of the intake air amount target value GAT under such a situation where the dither torque correction amount TrqD is not “0” is referred to as “dither time correction control”. That is, the intake air amount target value setting unit M41 can perform dither correction control.

  When the required torque Trq is corrected by the damping torque correction amount TrqS, the intake air amount target value GAT increases as the damping torque correction amount TrqS increases. That is, when the damping torque correction amount TrqS is larger than “0”, the intake air amount target value GAT is larger than when the damping torque correction amount TrqS is equal to “0”. Therefore, in the present embodiment, the calculation of the intake air amount target value GAT based on the required torque Trq corrected with the damping torque correction amount TrqS in this way is referred to as “sprung vibration damping control”. That is, the intake air amount target value setting unit M41 can perform sprung mass damping control.

  The throttle opening target value calculation unit M40 is provided with a reverse air model M42 to which the intake air amount target value GAT is input. The engine speed NE is also input to the reverse air model M42. Then, the reverse air model M42 calculates the engine load factor KL based on the intake air amount target value GAT and the engine speed NE. Further, the reverse air model M42 calculates a throttle opening target value TAT that is a target value of the throttle opening TA that is the opening of the throttle valve 14, based on the calculated engine load factor KL.

<Throttle valve controller M50>
The throttle valve controller M50 controls the operation of the throttle valve 14 so that the throttle opening TA approaches the throttle opening target value TAT calculated by the reverse air model M42 of the throttle opening target value calculator M40.

<Base injection amount calculation unit M60>
The base injection amount calculation unit M60 calculates the base injection amount QB based on the engine load factor KL calculated by the reverse air model M42 of the throttle opening target value calculation unit M40. The base injection amount QB is derived by multiplying the specified full-charge theoretical injection amount QTH by the engine load factor KL. As the full charge theoretical injection amount QTH, a calculated value of the fuel injection amount when the engine load factor KL is “100%” and the air-fuel ratio detection value AF is equal to the target air-fuel ratio AFT is set.

<Air-fuel ratio control unit M70>
The air-fuel ratio control unit M70 performs air-fuel ratio F / B control for updating the air-fuel ratio F / B correction value FAF so that the deviation between the air-fuel ratio detection value AF and the target air-fuel ratio AFT becomes small. In addition, the air-fuel ratio control unit M70 performs air-fuel ratio learning control for updating the air-fuel ratio learning value KG so that the absolute value of the air-fuel ratio F / B correction value FAF becomes small. The air-fuel ratio control unit M70 can determine that the learning of the air-fuel ratio is completed when the absolute value of the air-fuel ratio F / B correction value FAF does not exceed the specified value.

  Then, the air-fuel ratio control unit M70 corrects the base injection amount QB calculated by the base injection amount calculation unit M60 using the air-fuel ratio F / B correction value FAF and the air-fuel ratio learning value KG, so that each cylinder A required injection amount QBF which is a required supply amount into # 1 to # 4 is derived. For example, the required injection amount QBF can be calculated using the following relational expression (formula 1).

QBF = QB · (1 + FAF) · KG (Formula 1)
<Dither control unit M80>
The dither control unit M80 performs dither control when a predetermined dither control execution condition is satisfied. For example, the dither control execution condition includes that the temperature of the three-way catalyst 17 is required to be increased, and that the target air-fuel ratio AFT is equal to the stoichiometric air-fuel ratio.

In the dither control performed in the present embodiment, the required injection amount QBF calculated by the air-fuel ratio control unit M70 is corrected so as to satisfy the following conditions.
(Condition 2-1) The first cylinder # 1 is a rich combustion cylinder in which the air-fuel ratio of the air-fuel mixture becomes richer than the target air-fuel ratio AFT (ie, the stoichiometric air-fuel ratio), and other than the first cylinder # 1 Cylinders # 2 to # 4 become lean combustion cylinders in which the air-fuel ratio of the air-fuel mixture becomes leaner than the target air-fuel ratio AFT (that is, the stoichiometric air-fuel ratio).
(Condition 2-2) The average value of the air-fuel ratio of the air-fuel mixture in all the cylinders # 1 to # 4 including the rich combustion cylinder and the lean combustion cylinder is equal to the target air-fuel ratio AFT.

  The dither control unit M80 is provided with a request value calculation unit M81 that calculates the injection amount correction request value α. The required value calculation unit M81 makes the injection amount correction request value α equal to “0” when the dither control is not performed, and sets the injection amount correction request value α to a value larger than “0” when the dither control is performed. . As described above, the injection amount correction request value α is also used in the calculation of the dither torque correction amount TrqD of the dither correction torque calculation unit M12.

  The dither control unit M80 also calculates a rich correction request value calculation unit M82 for calculating the injection amount correction request value βi for the rich combustion cylinder, and a lean correction request for calculating the injection amount correction request value βd for the lean combustion cylinder. A value calculation unit M83. The rich correction request value calculation unit M82 sets the sum obtained by adding “1” to the injection amount correction request value α calculated by the request value calculation unit M81 as the injection amount correction request value βi for the rich combustion cylinder. The lean correction request value calculation unit M83 adds a sum of “1” to the product obtained by multiplying the injection amount correction request value α calculated by the request value calculation unit M81 by “−1 / N” for the lean combustion cylinder. The injection amount correction request value βd is used. “N” is the number of lean combustion cylinders, and is “3” in the present embodiment.

  The dither control unit M80 includes a rich correction processing unit M84 that calculates an injection amount command value QBFi for a rich combustion cylinder, and a lean correction processing unit M85 that calculates an injection amount command value QBFd for a lean combustion cylinder. Have. The rich correction processing unit M84 multiplies the product obtained by multiplying the required injection amount QBF calculated by the air-fuel ratio control unit M70 by the injection amount correction request value βi (= 1 + α) for the rich combustion cylinder, an injection amount command for the rich combustion cylinder. Let it be the value QBFi. The lean correction processing unit M85 multiplies the required injection amount QBF by the injection amount correction request value βd (= 1-α / N) for the lean combustion cylinder as an injection amount command value QBFd for the lean combustion cylinder.

<Injection valve control unit M90>
The injection valve control unit M90 is for the first cylinder # 1 so that the amount of fuel injected from the fuel injection valve 13 for the first cylinder # 1 is equal to the injection amount command value QBFi for the rich combustion cylinder. The fuel injection valve 13 is driven. Further, the injection valve control unit M90 determines that the amount of fuel injected from the fuel injection valves 13 for the cylinders # 2 to # 4 other than the first cylinder # 1 is the injection amount command value QBFd for the lean combustion cylinder. The fuel injection valves 13 for the cylinders # 2 to # 4 are driven so as to be equal.

Next, a processing routine that is repeatedly executed by the drive torque converter M24 will be described with reference to FIG.
As shown in FIG. 3, in the present processing routine, the drive torque conversion unit M24 determines whether or not the conditions for executing the sprung mass damping control are satisfied (S11). That is, the drive torque conversion unit M24 determines that the execution condition is satisfied when any of the above conditions 1-1, 1-2, and 1-3 is satisfied. On the other hand, the drive torque converter M24 does not determine that the execution condition is satisfied when at least one of the conditions 1-1, 1-2, and 1-3 is not satisfied. If the execution condition is not satisfied (S11: NO), the drive torque conversion unit M24 proceeds to step S14 described later.

  On the other hand, when the execution condition of the sprung mass damping control is satisfied (S11: YES), the drive torque converter M24 determines whether or not the execution condition of the dither control is satisfied (S12). When the execution condition for the dither control is satisfied (S12: YES), since the dither control is performed, the drive torque converting unit M24 proceeds to step S14 described later. On the other hand, when the execution condition of the dither control is not satisfied (S12: NO), the drive torque conversion unit M24 uses the vibration suppression wheel torque correction amount WTrq1 derived by the vibration suppression correction amount calculation unit M23 for vibration suppression. By converting to the torque correction amount TrqS, the damping torque correction amount TrqS is derived (S13). Then, the drive torque conversion unit M24 once ends this processing routine.

  In step S14, the drive torque conversion unit M24 makes the damping torque correction amount TrqS equal to “0”. Thereafter, the drive torque conversion unit M24 once ends this processing routine.

Next, a processing routine that is repeatedly executed by the request value calculation unit M81 will be described with reference to FIG.
As shown in FIG. 4, in the present processing routine, the required value calculation unit M81 determines whether or not the above-described dither control execution condition is satisfied (S21). When the execution condition is not satisfied (S21: NO), the request value calculation unit M81 once ends this processing routine. On the other hand, when the execution condition is satisfied (S21: YES), the required value calculation unit M81 determines whether or not the sprung mass damping control is still executed (S22). When the sprung mass damping control is still executed (S22: YES), the required value calculation unit M81 repeats the determination in step S22 until the completion of the sprung mass damping control is completed.

  On the other hand, when the sprung mass damping control is not performed (S22: NO), the request value calculation unit M81 sets the injection amount correction request value α so that the injection amount correction request value α is larger than “0”. Calculate (S23). Subsequently, the request value calculation unit M81 determines whether or not a dither control termination condition is satisfied (S24). An example of the dither control termination condition is that the temperature increase of the three-way catalyst 17 has been completed.

  When the dither control termination condition is not satisfied (S24: NO), the request value calculation unit M81 proceeds to step S23 described above. That is, the execution of dither control is continued. On the other hand, when the termination condition is satisfied (S24: YES), the required value calculation unit M81 performs a gradual decrease process for gradually decreasing the injection amount correction required value α toward “0” (S25). When the injection amount correction request value α becomes equal to “0” and the gradual decrease process is completed, the request value calculation unit M81 once ends this processing routine. That is, the execution of the dither control is terminated.

Next, referring to FIG. 5, an explanation will be given of the operation when starting the execution of the dither control while the vehicle is running, together with the effects. It is assumed that the target air / fuel ratio AFT is equal to the theoretical air / fuel ratio.
Before the timing t1 shown in FIG. 5, the conditions for executing the dither control are not satisfied, while the conditions for executing the sprung mass damping control are satisfied. Therefore, as shown in FIG. 5, before the timing t1, the dither control is not performed, but the sprung mass damping control is performed. As a result, during the period in which the sprung vibration occurs, the throttle opening degree TA is corrected by correcting the intake air amount target value GAT by performing the sprung mass damping control.

  In the timing chart shown in FIG. 5, in the timing chart showing the transition of the sprung vibration, the solid line indicates the spring according to the present embodiment that can perform the sprung mass damping control when the dither control execution condition is not satisfied. It shows the transition of the upper vibration. On the other hand, the broken line indicates the transition of the sprung vibration in the comparative example in which the sprung mass damping control is not performed. In the timing chart shown in FIG. 5, in the timing chart showing the transition of the throttle opening TA (intake air amount GA), the solid line shows the transition of the throttle opening TA (intake air amount GA) in the present embodiment. ing. On the other hand, the broken line shows the transition of the throttle opening degree TA (intake air amount GA) in the comparative example in which the sprung mass damping control, the dither control, and the dither correction control are not performed.

  Before the timing t1, the wheel torque generated by the wheel 101 (drive wheel) is corrected by correcting the throttle opening degree TA by performing the sprung mass damping control. Thereby, sprung vibration can be suppressed. However, the period during which sprung vibration occurs is very short. By correcting the throttle opening TA, that is, the intake air amount GA in such a very short period, the center of the air-fuel ratio, which is also the average value of the air-fuel ratio of the air-fuel mixture in all the cylinders # 1 to # 4, is increased. May fluctuate.

  Thereafter, the dither control execution condition is satisfied at timing t1. Then, the implementation of sprung mass damping control is terminated. Then, the execution of dither control is started. When the dither control is performed, the output torque of the internal combustion engine 10 tends to decrease.

  Therefore, when dither control is performed, dither correction control is also performed. That is, since the dither torque correction amount TrqD is larger than “0”, the throttle opening degree TA, that is, the intake air amount GA is corrected to be increased. Thereby, the fall of the output torque of the internal combustion engine 10 during execution of dither control can be suppressed.

  In the present embodiment, when the dither control and the dither correction control are performed, the execution of the sprung mass damping control is prohibited. When the dither control and the dither correction control are performed, by prohibiting the execution of the sprung mass damping control, the correction of the intake air amount GA by the dither correction control and the correction of the intake air amount GA by the sprung mass damping control are performed. Can be prevented from interfering with each other. As a result, a sudden change in the intake air amount GA is suppressed. Therefore, during the execution of the dither control, fluctuations in the air-fuel ratio of the air-fuel mixture in each cylinder # 1 to # 4 can be suppressed, and consequently the combustion of the air-fuel mixture in each cylinder # 1 to # 4 becomes unstable. This can be suppressed.

(Second Embodiment)
Next, a second embodiment of the control apparatus for an internal combustion engine will be described with reference to FIGS. The second embodiment is different from the first embodiment in that when the sprung mass damping control is performed, the execution of the dither control and the dither correction control is prohibited. Therefore, in the following description, parts different from those of the first embodiment will be mainly described, and the same or corresponding member configurations as those of the first embodiment are denoted by the same reference numerals, and redundant description will be given. Shall be omitted.

With reference to FIG. 6, the processing routine repeatedly executed by the drive torque converter M24 will be described.
As shown in FIG. 6, in this processing routine, the drive torque conversion unit M24 determines whether or not the above-described sprung mass damping control execution condition is satisfied (S31). When the execution condition is not satisfied (S31: NO), the drive torque conversion unit M24 makes the damping torque correction amount TrqS equal to “0” (S32). Thereafter, the drive torque conversion unit M24 once ends this processing routine.

  On the other hand, when the execution condition of the sprung mass damping control is satisfied (S31: YES), the drive torque conversion unit M24 determines whether or not the dither control is being performed (S33). When the dither control is still performed (S33: YES), the drive torque converter M24 repeats the determination in step S33 until the dither control is finished. On the other hand, when the dither control is not performed (S33: NO), the drive torque conversion unit M24 derives the damping torque correction amount TrqS in the same manner as in step S13 (S34). Thereafter, the drive torque conversion unit M24 once ends this processing routine.

Next, a processing routine that is repeatedly executed by the request value calculation unit M81 will be described with reference to FIG.
As shown in FIG. 7, in the present processing routine, the required value calculation unit M81 determines whether or not the above-described dither control execution condition is satisfied (S41). When the execution condition is not satisfied (S41: NO), the request value calculation unit M81 once ends this processing routine. On the other hand, when the execution condition is satisfied (S41: YES), the required value calculation unit M81 determines whether or not the execution condition for the sprung mass damping control is satisfied (S42).

  When the execution condition of the sprung mass damping control is not satisfied (S42: NO), the request value calculation unit M81 calculates the injection amount correction request value α, similarly to step S23 (S43). Subsequently, the request value calculation unit M81 determines whether or not a dither control end condition is satisfied, similarly to step S24 (S44). If the end condition for the dither control is not satisfied (S44: NO), the request value calculation unit M81 shifts the process to the above-described step S42. That is, if the execution condition for the sprung mass damping control is not satisfied, the execution of the dither control is continued.

  On the other hand, when the dither control end condition is satisfied (S44: YES), the request value calculation unit M81 performs the gradual decrease process of the injection amount correction request value α in the same manner as in step S25 (S45). When the injection amount correction request value α becomes equal to “0” and the gradual decrease process is completed, the request value calculation unit M81 once ends this processing routine. That is, the execution of the dither control is terminated.

  On the other hand, when the execution condition of the sprung mass damping control is satisfied in step S42 (YES), the required value calculation unit M81 shifts the process to the above-described step S45. That is, even when the dither control is being performed, if the execution condition for the sprung mass damping control is satisfied, the execution of the dither control is terminated.

As described above, according to the present embodiment, the following effects can be obtained.
In the present embodiment, when the sprung mass damping control is performed, the dither control and the dither correction control are prohibited. Thereby, the correction of the intake air amount GA by the dither correction control and the correction of the intake air amount GA by the sprung mass damping control can be prevented from interfering with each other. As a result, a sudden change in the intake air amount GA is suppressed. Therefore, fluctuations in the air-fuel ratio of the air-fuel mixture in each of the cylinders # 1 to # 4 can be suppressed, and consequently the combustion of the air-fuel mixture in each of the cylinders # 1 to # 4 can be suppressed from becoming unstable.

The above embodiment may be changed to another embodiment as described below.
In the first embodiment, the sprung mass damping control is not performed when the dither control and the dither correction control are performed. However, if the degree of interference between the correction of the intake air amount GA by performing the dither correction control and the correction of the intake air amount GA by performing the sprung mass damping control can be reduced, the dither control is being performed. The sprung mass damping control may be performed. However, in this case, it is preferable to limit the correction amount of the intake air amount GA by performing the sprung mass damping control. For example, the damping torque correction amount TrqS derived by the drive torque converter M24 is multiplied by a predetermined correction gain (a value greater than 0 and less than 1), and the damping torque correction after this decrease correction is performed. The amount TrqS is input to the adder M14 of the required torque setting unit M10. As a result, the correction amount of the intake air amount GA due to the execution of the sprung mass damping control can be reduced by the amount that the increase correction of the required torque Trq is suppressed.

  Further, the smaller value of the damping torque correction amount TrqS derived by the drive torque conversion unit M24 and the preset limiting torque correction value is set as the required torque as the damping torque correction amount TrqS. You may make it input into the adder M14 of the setting part M10. Even if such a control configuration is adopted, it is possible to limit the correction of the intake air amount GA by performing the sprung mass damping control.

  As described above, during the execution of the dither control and the dither correction control, the spring is controlled by limiting the sprung mass damping control, that is, by limiting the correction of the intake air amount GA by performing the sprung mass damping control. Compared to the case where no restriction is imposed on the upper vibration suppression control, the intake air amount GA is suppressed from changing suddenly. Therefore, fluctuations in the air-fuel ratio of the air-fuel mixture in each of the cylinders # 1 to # 4 can be suppressed, and consequently the combustion of the air-fuel mixture in each of the cylinders # 1 to # 4 can be suppressed from becoming unstable.

  In the second embodiment, when the sprung mass damping control is performed, the dither control and the dither correction control are not performed. However, if the degree of interference between the correction of the intake air amount GA by performing the dither correction control and the correction of the intake air amount GA by performing the sprung mass damping control can be reduced, the sprung mass damping control is performed. The dither control and the dither correction control may be performed even during the execution of the above. However, in this case, it is preferable to provide a limit to the dither control, that is, to limit the injection amount correction request value α calculated when the dither control is performed. For example, the injection amount correction request value α calculated by the request value calculation unit M81 is multiplied by a predetermined correction gain (a value greater than 0 and less than 1), and the injection amount correction request value α after this decrease correction is performed. Is input to the rich correction request value calculation unit M82, the lean correction request value calculation unit M83, and the dither correction torque calculation unit M12. In this case, the correction amount of the intake air amount GA due to the execution of the dither correction control can be reduced by the amount that the dither torque correction amount TrqD is less likely to increase.

  Further, the smaller one of the injection amount correction request value α calculated by the request value calculation unit M81 and the restriction correction request value set in advance is set as the injection amount correction request value α for the rich correction request. The value calculation unit M82, the lean correction request value calculation unit M83, and the dither correction torque calculation unit M12 may be input. Even if such a control configuration is adopted, the correction amount of the intake air amount GA by performing the dither correction control can be reduced.

  In this way, during the execution of the sprung mass damping control, there is no restriction on the dither control by providing a restriction on the dither control, that is, by providing a restriction on the correction of the intake air amount GA by performing the dither correction control. Compared to the case, a sudden change in the intake air amount GA is suppressed. Therefore, fluctuations in the air-fuel ratio of the air-fuel mixture in each of the cylinders # 1 to # 4 can be suppressed, and consequently the combustion of the air-fuel mixture in each of the cylinders # 1 to # 4 can be suppressed from becoming unstable.

  In the dither control performed in each of the above embodiments, the fuel supply amount into the rich combustion cylinder so that the average value of the air-fuel ratio of the air-fuel mixture in all the cylinders # 1 to # 4 is equal to the stoichiometric air-fuel ratio And the fuel supply amount into the lean fuel cylinder. However, not limited to this, in the dither control, the air-fuel ratio of the air-fuel mixture in the rich combustion cylinder is richer than the stoichiometric air-fuel ratio, and the air-fuel ratio of the air-fuel mixture in the lean combustion cylinder is leaner than the stoichiometric air-fuel ratio. If so, the average value of the air-fuel ratio of the air-fuel mixture in all the cylinders # 1 to # 4 may be different from the stoichiometric air-fuel ratio.

  In each of the above embodiments, the number of lean combustion cylinders is greater than the number of rich combustion cylinders, but this is not a limitation. For example, the number of lean combustion cylinders may be the same as the number of rich combustion cylinders, or the number of lean combustion cylinders may be smaller than the number of rich combustion cylinders. Further, each cylinder # 1 to # 4 may include a stoichiometric combustion cylinder in which the air-fuel ratio of the air-fuel mixture is equal to the stoichiometric air-fuel ratio as long as it includes a lean combustion cylinder and a rich combustion cylinder.

In each of the above embodiments, an example in which the rich combustion cylinder is fixed by the first cylinder # 1 has been described. However, the rich combustion cylinder may be appropriately changed during the dither control.
The internal combustion engine 10 may be an internal combustion engine other than the 4-cylinder internal combustion engine (for example, a 6-cylinder internal combustion engine).

  The internal combustion engine 10 may include a fuel injection valve that injects fuel into the intake passage 12 instead of the fuel injection valve 13 that directly injects fuel into the combustion chamber 11. The internal combustion engine 10 may be provided with a fuel injection valve 13 that directly injects fuel into the combustion chamber 11 and a fuel injection valve that injects fuel into the intake passage 12 for each cylinder.

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 20 ... Control apparatus, M41 ... Intake amount target value setting part, M80 ... Dither control part, # 1- # 4 ... Cylinder.

Claims (1)

Some cylinders of the plurality of cylinders of the internal combustion engine become rich combustion cylinders in which the air-fuel ratio of the air-fuel mixture becomes richer than the stoichiometric air-fuel ratio, and cylinders different from the rich combustion cylinders among the cylinders A dither control unit that performs dither control to adjust the fuel supply amount into each cylinder so that the air-fuel ratio of the air-fuel mixture becomes leaner than the stoichiometric air-fuel ratio;
An intake air amount target value calculating unit that calculates an intake air amount target value that is a target value of the intake air amount;
The intake air amount target value calculation unit
When the dither control is performed, the dither correction control for calculating the intake amount target value so that the intake amount target value is larger than when the dither control is not performed;
And a sprung mass damping control for correcting the intake air amount target value in accordance with the sprung vibration of the vehicle,
A control device for an internal combustion engine that prohibits the execution of the other control or restricts the control of the other when either one of the dither control and the sprung mass damping control is being performed.