JP2010007528A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the control accuracy of an actuator while preventing the occurrence of hunching in control over the actuator by an operation influence of the actuator on a predetermined physical amount when controlling the operation of the actuator according to the predetermined physical amount related to an engine output such as an air volume. <P>SOLUTION: The operation of a variable valve timing mechanism (VVT) is controlled according to first target valve timing (first target VT) which is set based on a target air volume (target KL). Actual valve timing (actual VT) as the control result thereof is obtained, and a difference (VT deviation) between the actual VT and a second target valve timing (second VT) set based on the actual KL is calculated. A target VT correction amount is calculated by the integration of VT deviation, and the first target VT is corrected by the target VT correction amount. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a control device for an internal combustion engine, and more particularly to an actuator that is controlled in operation according to a predetermined physical quantity related to engine output, and that includes an actuator whose operation affects the physical quantity. Relates to the device.

  The internal combustion engine is provided with a plurality of actuators such as an EGR device, a variable valve timing mechanism, or a swirl control valve. By appropriately operating these actuators, various functions such as improvement of fuel consumption and reduction of exhaust emission can be realized. Further, as information for controlling the operation of these actuators, a predetermined physical quantity related to the engine output such as the air amount and the intake pressure is used.

  However, depending on the type of actuator, the physical quantity may change due to the influence of its operation. For example, when the valve timing is changed by the variable valve mechanism, the air amount (cylinder intake air amount) also changes. When the target value of the valve timing is set based on the actual air amount, the target value is changed according to the change in the air amount, and the valve timing must be changed again.

  Such a control system is called a double control system, and FIG. 4 shows a block diagram of the entire configuration. When the configuration shown in FIG. 4 is applied to the control system of the aforementioned variable valve timing mechanism, the controlled object 1 is the air amount and the controlled object 2 is the valve timing. Then, the target value determination unit determines the target value of the valve timing based on the air amount. In the dual control system, when the input of the control object 1 changes, the control object 1 changes and the target value of the control object 2 changes. Then, when the controlled object 2 changes according to the change of the target value, the input of the controlled object 1 changes, and the controlled object 1 changes again. Since such an operation is repeated, hunting occurs in the operation of the controlled object 2 in the dual control system.

Regarding such a problem, Japanese Patent Application Laid-Open No. 2002-332884 discloses a technique for determining a target operation amount of each actuator from a target air amount instead of an actual air amount. For example, the target EGR opening degree of the EGR device is determined from the target air amount, and the target VVT advance value of the variable valve timing mechanism (VVT) is determined from the target air amount. According to this, it is possible to avoid the occurrence of hunting in the operation of the actuator due to the actual fluctuation of the air amount.
JP 2002-332884 A

  However, in the control of the internal combustion engine, the actual air amount does not necessarily match the target air amount. Due to the effects of calculation errors when calculating the throttle opening based on the target air volume, aging of the throttle, individual differences, sensor errors used to calculate the air volume, etc. There may be a steady error during the period.

  In the technique described in the above publication, the target operation amount of the actuator is determined based on the target air amount. For this reason, the operation amount of the actuator actually realized according to the target operation amount is not necessarily the optimum operation amount for the actual air amount. For example, in the case of a variable valve timing mechanism, the valve timing may be controlled to an incorrect phase. That is, although the technique described in the above publication is effective in avoiding hunting, there is room for improvement in the control accuracy of the actuator.

  The present invention has been made to solve the above-described problems. When the operation of the actuator is controlled in accordance with a predetermined physical quantity related to the engine output such as the air quantity, the influence of the operation on the physical quantity. Accordingly, an object of the present invention is to provide a control device for an internal combustion engine that can improve the control accuracy of the actuator while preventing hunting from occurring in the operation of the actuator.

In order to achieve the above object, the first invention is an actuator whose operation is controlled in accordance with a predetermined physical quantity (hereinafter referred to as output-related quantity) related to engine output, and the action affects the output-related quantity. In an internal combustion engine control device including an actuator for
Target output related quantity acquisition means for acquiring a target value of the output related quantity;
A temporary target operation amount setting means for setting a temporary target operation amount of the actuator based on the target output related amount;
Control means for controlling the operation of the actuator according to the temporary target operation amount;
Actual operation amount acquisition means for acquiring the actual operation amount of the actuator;
Actual output related quantity acquisition means for acquiring an actual value of the output related quantity;
Target operation amount setting means for setting a target operation amount of the actuator based on the actual output related amount;
An operation correction amount learning means for learning an operation correction amount for correcting a deviation between the temporary target operation amount and the target operation amount from a deviation between the target operation amount and the actual operation amount;
Temporary target motion amount correction means for correcting the temporary target motion amount by the motion correction amount;
It is characterized by having.

According to a second invention, in the first invention,
The apparatus further comprises delay processing means for delaying the target operation amount by the response delay time of the actuator.

According to a third invention, in the first or second invention,
The control means includes
A feedback control circuit comprising an element different from an element of the motion correction amount learning means among a proportional element, an integral element, and a derivative element; and a difference between the temporary target motion amount and the actual motion amount is determined by the feedback control circuit. An operation amount setting means for setting the operation amount of the actuator as the operation amount of the actuator;
Actuator driving means for driving the actuator according to the operation amount;
It is characterized by having.

According to a fourth invention, in the third invention,
The motion correction amount learning means has an integral element,
The feedback control circuit is characterized by comprising a proportional element and a differential element.

According to a fifth invention, in any one of the first to fourth inventions,
The output related quantity is an air quantity.

According to a sixth invention, in the fifth invention,
The actuator is a variable valve timing mechanism.

  According to the first invention, the temporary target operation amount of the actuator is set based on the target value, not the actual value of the output-related amount, and the operation of the actuator is controlled based on the temporary target operation amount. Even if the actual value of the output-related quantity changes due to the operation, it is possible to avoid the occurrence of hunting in the operation of the actuator.

  Further, according to the first invention, the deviation between the target motion amount and the temporary target motion amount based on the actual value of the output-related amount is determined by the motion correction amount learned from the deviation between the target motion amount and the actual motion amount. It is corrected. In addition, the influence of mutual interference that occurs between the actual movement amount of the actuator and the actual value of the output-related amount extends to the calculation of the movement correction amount, but the influence is absorbed in the learning process of the movement correction amount. The influence of interference is prevented from affecting the control of the actuator via the operation correction amount. Therefore, according to the first invention, the actual value of the output-related amount is prevented while preventing hunting in the operation of the actuator due to the influence of mutual interference between the actual operation amount of the actuator and the actual value of the output-related amount. The control result according to can be obtained.

  According to the second invention, the target operation amount is set at the same response speed as the operation of the actuator is reflected in the actual operation amount. According to this, even when there is a transient delay in the response of the actuator, it is possible to avoid a large deviation between the target operation amount and the actual operation amount. Stability can be ensured.

  According to the third aspect of the invention, control interference occurs between feedback control for bringing the actual motion amount of the actuator closer to the temporary target motion amount and feedback control for bringing the temporary target motion amount closer to the target motion amount. Can be prevented.

  According to the fourth invention, it is possible to slowly absorb the deviation between the temporary target motion amount and the target motion amount by learning while quickly converging the actual motion amount of the actuator to the temporary target motion amount.

  The fifth aspect of the invention relates to an actuator whose operation is controlled in accordance with the amount of air, and even if the amount of air changes due to the operation of the actuator, the control accuracy is improved while avoiding the occurrence of hunting. be able to.

  According to the sixth aspect of the invention, the control accuracy of the valve timing by the variable valve timing mechanism can be improved.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a control device for an internal combustion engine as the first embodiment of the present invention. The control device of the present embodiment is configured as a control device that controls the operation of a variable valve timing mechanism (hereinafter referred to as VVT) provided in the drive system of the intake valve. Hereinafter, the configuration of the control device of the present embodiment will be described with reference to FIG.

  The control device of the present embodiment sets the target valve timing (hereinafter referred to as target VT) for controlling the operation of the VVT based on the actual air amount (hereinafter referred to as actual KL), and at the same time, Hereinafter, it is also set based on the target KL). Hereinafter, the target VT determined from the target KL is referred to as a first target VT, and the target VT determined from the actual KL is referred to as a second target VT. The control device of the present embodiment uses the first target VT determined from the target KL as the basic target VT for actually operating the VVT.

  The control device according to the present embodiment controls the VVT according to the target KL setting unit 2 that sets the target KL, the first target VT setting unit 4 that sets the first target VT based on the target KL, and the first target VT. A VVT control unit 6 is provided. The target KL setting unit 2 sets the target KL based on the required torque for the internal combustion engine. The first target VT setting unit 4 calculates a VT corresponding to the target KL using a map prepared in advance, and sets it as the first target VT. The relationship between KL and VT defined in the map is determined from the viewpoint of various functions of the internal combustion engine such as fuel efficiency and exhaust emission. The VVT control unit 6 calculates a VVT operation amount (for example, OCV drive duty) from the first target VT, and operates the VVT according to the operation amount.

  The target KL set by the target KL setting unit 2 is also used in the intake control system 18. In the intake control system 18, the operation of the throttle is controlled so that the actual KL becomes the target KL. The valve timing (hereinafter, actual VT) realized by the operation of the VVT described above is reflected in the control of the intake control system 18.

  The change in the actual VT affects the actual KL. Although intake control is performed by the intake control system 18 so that the actual KL becomes the target KL, when the actual VT changes, a transitional change also occurs in the actual KL. For this reason, if the target VT is set based on the actual KL, a change in the actual KL and a change in the actual VT will affect each other, resulting in hunting in the operation of the VVT. In this regard, according to the configuration adopted by the control device of the present embodiment, the operation of the VVT is controlled by the first target VT set based on the target KL instead of the actual KL. Even if KL changes, it is avoided that hunting occurs in the operation of VVT.

  By the way, due to the control error of the intake control system 18, there may be a steady error between the target KL and the actual KL. In such a case, with the first target VT set based on the target KL, it is not always possible to realize the optimum valve timing according to the actual KL. In order to prevent the valve timing from being controlled to an incorrect phase, it is necessary to compensate for a deviation in valve timing due to a steady error between the target KL and the actual KL by some method.

  In the control device of the present embodiment, as a method for compensating for the deviation of the valve timing, the second target VT set from the actual KL is set as the true target VT, and the deviation between the second target VT and the actual VT is calculated. It was decided to correct the first target VT by the correction amount calculated using it. That is, by learning the deviation between the second target VT, which is the true target VT, and the first target VT from the deviation between the second target VT and the actual VT, the first target VT, which is the temporary target VT, is It was made to approach the target VT. In order to implement such a method, the control device of the present embodiment includes an actual KL calculation unit 8, a second target VT setting unit 10, a VT deviation calculation unit 12, an I control unit 14, and a target VT correction unit 16. Is provided.

  The actual KL calculation unit 8 calculates the actual KL based on the throttle opening. For calculating the actual KL, an air model in which the response of the air amount to the operation of the throttle is modeled by a mathematical formula or the like is used. In this air model, the output value of the air flow sensor, the engine speed, the actual VT, etc. are used as parameters.

  The second target VT setting unit 10 calculates a VT corresponding to the actual KL using a map prepared in advance, and sets it as the second target VT. The second target VT setting unit 10 and the first target VT setting unit 4 are different only in input, and the maps used there are common to both.

  The VT deviation calculation unit 12 calculates a difference (VT deviation) between the second target VT set by the second target VT setting unit 10 and the actual VT. The actual VT is calculated by the VVT control unit 6 based on the output value of the rotation angle sensor provided in the VVT.

  The I control unit 14 is a feedback control circuit including an integration element (I term), and integrates the VT deviation input from the VT deviation calculation unit 12. Then, a value obtained by multiplying the integrated value by a predetermined FB gain is output as a target VT correction amount.

  The target VT correction unit 16 is provided between the first target VT setting unit 4 and the VVT control unit 6, and is input from the I control unit 14 to the first target VT set by the first target VT setting unit 4. Add the VT correction amount. The corrected first target VT to which the target VT correction amount is added is input to the VVT controller 6.

  According to the above configuration, the deviation between the first target VT (provisional target VT) set from the target KL and the second target VT (true target VT) set from the actual KL is It can correct | amend by the target VT correction amount learned from the deviation with respect to 2nd target VT. By controlling the VVT in accordance with the first target VT corrected in this way, an optimum actual VT corresponding to the actual VL can be realized.

  In addition, since the fluctuation of the actual VL is reflected in the second target VT, the VT deviation that is the deviation between the actual VT and the second target VT is caused by the influence of mutual interference generated between the actual VT and the actual VL. fluctuate. However, since the target VT correction amount is an integral value of the VT deviation, the fluctuation due to the influence of mutual interference is smoothed and absorbed by the integration process, and the target VT correction quantity does not fluctuate due to the influence of mutual interference. That is, according to the above-described configuration, the influence of the mutual interference between the actual VT and the actual VL is prevented from reaching the control of the VVT via the target VT correction amount.

  In the first embodiment described above, KL (air amount) corresponds to the “output related amount” according to the first invention, and the target KL setting unit 2 serves as the “target output related amount acquisition means” of the first invention. Equivalent to. The first target VT setting unit 4 corresponds to the “temporary target operation amount setting means” of the first invention, and the first target VT set there corresponds to the “temporary target operation amount” according to the first invention. The VVT control unit 6 functions as the “control unit” of the first invention and as the “actual operation amount acquisition unit” of the first invention. The actual KL calculation unit 8 corresponds to the “actual output related amount acquisition unit” of the first invention. The second target VT setting unit 10 corresponds to the “target operation amount setting means” of the first invention, and the second target VT set there corresponds to the “target operation amount” according to the first invention. The VT deviation calculation unit 12 and the I control unit 14 constitute the “motion correction amount learning means” of the first invention. The target VT correction unit 16 corresponds to the “temporary target operation amount correction means” of the first invention.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to the drawings.

  FIG. 2 is a block diagram showing the configuration of the control device for the internal combustion engine as the second embodiment of the present invention. The control device of the present embodiment has a configuration in which new elements are added to the configuration of the control device of the first embodiment. In FIG. 2, elements common to the first embodiment are denoted by the same reference numerals. Hereinafter, the configuration of the control device of the present embodiment will be described with reference to FIG. However, the description of the configuration common to the first embodiment is omitted or simplified, and the configuration different from the first embodiment is mainly described.

  The control device of the present embodiment has a configuration in which a VVT model 20 is added between the second target VT setting unit 10 and the VT deviation calculation unit 12 in the configuration of the control device of the first embodiment. The VVT model 20 models a response delay between input and output in the VVT, specifically, a response delay of the actual VT with respect to a change in the target VT. The modeling may use a physical model or a statistical model. Alternatively, a simple mathematical model expressed by dead time and first-order lag element may be used. The second target VT set by the second target VT setting unit 10 is delayed by the VVT model 20 and then input to the VT deviation calculating unit 12.

  According to the control device of the present embodiment, after the first target VT is set by the first target VT setting unit 4, the first target VT is reflected on the actual VT through the control by the VVT control unit 6. And the response speed until the second target VT is reflected in the calculation of the VT deviation in the VT deviation calculation unit 12 after the second target VT is set by the second target VT setting unit 10 Can be aligned. According to this, even when there is a transient delay in the response of the VVT, it is possible to avoid a large deviation between the second target VT compared with the VT deviation calculating unit 12 and the actual VT. . Therefore, according to the control device of the present embodiment, it is possible to ensure the stability of the VVT control during the transition without setting the FB gain of the I control unit 14 low.

  In the second embodiment described above, the VVT model 20 corresponds to the “delay processing means” of the second invention. The other correspondence relationship between the second embodiment and the present invention is common to the correspondence relationship between the first embodiment and the present invention.

Embodiment 3 FIG.
Next, Embodiment 3 of the present invention will be described with reference to the drawings.

  FIG. 3 is a block diagram showing the configuration of the control device for the internal combustion engine as the third embodiment of the present invention. The control device according to the present embodiment is based on the control device according to the first embodiment and is characterized by the internal configuration of the VVT control unit 6. In FIG. 3, elements common to the first embodiment are denoted by the same reference numerals. Hereinafter, the configuration of the control device of the present embodiment will be described with reference to FIG. However, the description of the configuration common to the first embodiment is omitted or simplified, and the configuration different from the first embodiment is mainly described.

  As shown in FIG. 3, the VVT control unit 6 according to this embodiment includes a VT deviation calculation unit 30, a PD control unit 32, and a VVT drive unit 34. The VT deviation calculation unit 30 calculates a deviation between the first target VT input to the VVT control unit 6 and the actual VT output from the VVT control unit 6. The PD control unit 32 is a feedback control circuit including a proportional element (P term) and a differential element (D term). The VT deviation input from the VT deviation calculation unit 30 is subjected to proportional processing and differential processing, and the calculated value is obtained. Output as VVT manipulated variable. The VVT drive unit 34 drives the VVT by the operation amount input from the PD control unit 32, and calculates and outputs the actual VT from the drive result. According to such a configuration of the VVT control unit 6, the actual VT can be quickly brought close to the first target VT (the first target VT after being corrected by the target VT correction amount).

  In the configuration shown in FIG. 3, the feedback control system for bringing the first target VT closer to the second target dynamic VT and the feedback control system for bringing the actual VT closer to the first target VT overlap. In general, in such a double feedback control system, there is a concern about control interference between two feedback controls. However, since the control device of the present embodiment uses low frequency feedback control by I control and one side by high frequency feedback control by PD control, it is avoided to give control interference to each other. . According to the control device of the present embodiment, the actual VT is quickly converged to the first target VT, and the deviation between the first target VT and the second target VT is slowly absorbed into the target VT correction amount by learning. be able to.

  In the third embodiment described above, the VT deviation calculation unit 30 and the PD control unit 32 constitute the “operation amount setting means” of the third invention. The VVT drive unit 34 corresponds to the “actuator drive unit” of the third invention. Regarding the other correspondence relationship between the third embodiment and the present invention, it is common to the correspondence relationship between the first embodiment and the present invention.

Others.
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, the following modifications can be made.

  The configuration of VVT control unit 6 according to the third embodiment can also be applied to the configuration of the control device of the second embodiment. In the third embodiment, the feedback control circuit provided in the VVT control unit 6 is a PD control circuit, but a P control circuit may be used.

  In the above-described embodiment, the present invention is applied to control of VVT. However, the present invention can also be applied to control of an EGR device, SCV, ignition device, or the like. These actuators are also common to the VVT in that the target operation amount is set in accordance with the air amount and the operation affects the actual air amount. In the above-described embodiment, the air amount is used as the output-related amount, but torque may be used as the output-related amount. The torque is also a physical quantity related to the engine output like the air quantity, and is affected by the operation of an actuator such as VVT.

It is a block diagram which shows the structure of the control apparatus of the internal combustion engine as Embodiment 1 of this invention. It is a block diagram which shows the structure of the control apparatus of the internal combustion engine as Embodiment 2 of this invention. It is a block diagram which shows the structure of the control apparatus of the internal combustion engine as Embodiment 3 of this invention. It is a figure for demonstrating the problem of a double control system.

Explanation of symbols

2 Target KL setting unit 4 First target VT setting unit 6 VVT control unit 8 Actual KL calculation unit 10 Second target VT setting unit 12 VT deviation calculation unit 14 I control unit 16 Target VT correction unit 18 Intake control system 20 VVT model 30 VT deviation calculation unit 32 PD control unit 34 VVT drive unit

Claims (6)

In an internal combustion engine control apparatus comprising an actuator whose operation is controlled according to a predetermined physical quantity related to engine output (hereinafter, output-related quantity), the operation of which affects the output-related quantity.
Target output related quantity acquisition means for acquiring a target value of the output related quantity;
A temporary target operation amount setting means for setting a temporary target operation amount of the actuator based on the target output related amount;
Control means for controlling the operation of the actuator according to the temporary target operation amount;
Actual operation amount acquisition means for acquiring the actual operation amount of the actuator;
Actual output related quantity acquisition means for acquiring an actual value of the output related quantity;
Target operation amount setting means for setting a target operation amount of the actuator based on the actual output related amount;
An operation correction amount learning means for learning an operation correction amount for correcting a deviation between the temporary target operation amount and the target operation amount from a deviation between the target operation amount and the actual operation amount;
Temporary target motion amount correction means for correcting the temporary target motion amount by the motion correction amount;
A control device for an internal combustion engine, comprising: 2. The control apparatus for an internal combustion engine according to claim 1, further comprising delay processing means for delaying the target operation amount by a response delay time of the actuator. The control means includes
A feedback control circuit comprising an element different from an element of the motion correction amount learning means among a proportional element, an integral element, and a derivative element; and a difference between the temporary target motion amount and the actual motion amount An operation amount setting means for setting the operation amount of the actuator as the operation amount of the actuator;
Actuator driving means for driving the actuator according to the operation amount;
The control apparatus for an internal combustion engine according to claim 1, further comprising: The motion correction amount learning means has an integral element,
4. The control device for an internal combustion engine according to claim 3, wherein the feedback control circuit includes a proportional element and a differential element.   The control apparatus for an internal combustion engine according to any one of claims 1 to 4, wherein the output-related quantity is an air quantity.   6. The control apparatus for an internal combustion engine according to claim 5, wherein the actuator is a variable valve timing mechanism.

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