JP2019007428A - Control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively reduce smoke during rapid acceleration of an internal combustion engine. One aspect of the present invention provides a control device for an internal combustion engine. The internal combustion engine 1 includes a variable displacement turbocharger 14 having a variable vane 28 and an EGR device 30 having an EGR valve 33, and the control device is configured to control the opening degree of the variable vane and the EGR valve. A control unit 100 is provided. The control unit sets the minimum opening of the variable vane based on the operating state of the internal combustion engine and the opening of the EGR valve, and continuously changes the minimum opening of the variable vane according to the opening of the EGR valve. Let [Selection diagram] Figure 1

Description

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

  For example, an internal combustion engine for a vehicle is known that includes a variable displacement turbocharger having a variable vane at a turbine inlet and an EGR device having an EGR valve (see, for example, Patent Documents 1-3).

JP 2002-161791 A Japanese Patent Laid-Open No. 10-231730 JP 2005-180234 A

  During rapid acceleration of the internal combustion engine, the opening degree of the variable vane is decreased, and the boost pressure or boost pressure is increased. However, at this time, the exhaust pressure increases momentarily with respect to the intake pressure, excessive EGR gas flows into the cylinder, and smoke may deteriorate. In order to suppress this smoke deterioration, a minimum value or a guard value related to the variable vane opening is set so that the variable vane opening does not decrease below this minimum value. However, conventionally, since this minimum value is not an appropriate value, it is difficult to effectively reduce smoke during sudden acceleration.

  Accordingly, the present invention has been made in view of such circumstances, and an object thereof is to provide a control device for an internal combustion engine that can effectively reduce smoke during sudden acceleration of the internal combustion engine.

According to one aspect of the invention,
A control device for an internal combustion engine,
The internal combustion engine includes a variable displacement turbocharger having a variable vane and an EGR device having an EGR valve,
The control device includes a control unit configured to control the opening of the variable vane and the EGR valve,
The control unit sets the minimum opening of the variable vane based on the operating state of the internal combustion engine and the opening of the EGR valve, and the minimum opening of the variable vane according to the opening of the EGR valve. A control device for an internal combustion engine is provided, characterized in that the degree is continuously changed.

  Preferably, the control unit continuously increases the minimum opening of the variable vane in accordance with an increase in the opening of the EGR valve.

Preferably, the control unit is
Calculating a first vane minimum opening, which is a variable vane minimum opening when the EGR valve is closed, based on an operating state of the internal combustion engine;
Calculating a second vane minimum opening, which is a variable vane minimum opening when the EGR valve is opened, based on an operating state of the internal combustion engine;
Calculating a weight based on the operating state of the internal combustion engine and the opening of the EGR valve;
The minimum opening of the variable vane is calculated by weighted averaging the first vane minimum opening and the second vane minimum opening by the weight.

  According to the present invention, smoke at the time of sudden acceleration of the internal combustion engine can be effectively reduced.

It is the schematic which shows the structure of embodiment of this invention. It is a flowchart of the control routine in this embodiment. It is a figure which shows various maps. It is a figure which shows various maps. It is a map which shows an example of the value of a weight. It is a table | surface which shows an example of the numerical change in the control of this embodiment. It is a graph which shows an example of the numerical change in the control of this embodiment. It is the time chart which compared the result of control with this embodiment and a comparative example.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. It should be noted that the present invention is not limited to the following embodiments.

  FIG. 1 is a schematic diagram showing a configuration of an embodiment of the present invention. An internal combustion engine (also referred to as an engine) 1 is a multi-cylinder engine mounted on a vehicle (not shown). In the present embodiment, the vehicle is a large vehicle such as a truck, and the engine 1 as a vehicle power source mounted on the vehicle is an in-line four-cylinder diesel engine. However, there are no particular limitations on the types, types, applications, etc. of the vehicle and the internal combustion engine. For example, the vehicle may be a small vehicle such as a passenger car, and the engine 1 may be a gasoline engine.

  The engine 1 includes an engine body 2, an intake passage 3 and an exhaust passage 4 connected to the engine body 2, a turbocharger 14, and a fuel injection device 5. The engine body 2 includes structural parts such as a cylinder head, a cylinder block, and a crankcase, and movable parts such as a piston, a crankshaft, and a valve housed therein.

  The fuel injection device 5 includes a common rail fuel injection device, and includes a fuel injection valve, that is, an injector 7 provided in each cylinder, and a common rail 8 connected to the injector 7. The injector 7 directly injects fuel into the cylinder 9, that is, into the combustion chamber. The common rail 8 stores the fuel injected from the injector 7 in a high pressure state.

  The intake passage 3 is mainly defined by an intake manifold 10 connected to the engine body 2 (particularly a cylinder head) and an intake pipe 11 connected to the upstream end of the intake manifold 10. The intake manifold 10 distributes and supplies the intake air sent from the intake pipe 11 to the intake ports of each cylinder. The intake pipe 11 is provided with an air cleaner 12, an air flow meter 13, a compressor 14 </ b> C of the turbocharger 14, an intercooler 15, and an electronically controlled intake throttle valve 16 in order from the upstream side. The air flow meter 13 is a sensor for detecting an intake air amount per unit time of the engine 1, that is, an intake flow rate, and is also referred to as a MAF sensor or the like.

  The exhaust passage 4 is mainly defined by an exhaust manifold 20 connected to the engine body 2 (particularly a cylinder head) and an exhaust pipe 21 disposed on the downstream side of the exhaust manifold 20. The exhaust manifold 20 collects exhaust gas sent from the exhaust port of each cylinder. A turbine 14 </ b> T of the turbocharger 14 is provided between the exhaust pipe 21 or between the exhaust manifold 20 and the exhaust pipe 21. In the exhaust pipe 21 downstream of the turbine 14T, an oxidation catalyst 22, a particulate filter (DPF) 23, a selective reduction type NOx catalyst (SCR) 24, and an ammonia oxidation catalyst 26 are provided in this order from the upstream side. An addition valve 25 for adding urea water as a reducing agent is provided on the upstream side of the NOx catalyst 24, particularly in the exhaust passage 4 near the inlet.

  The turbocharger 14 is a variable capacity turbocharger. The turbocharger 14 includes a plurality of variable vanes 28 for making the opening degrees of the nozzles at the turbine inlet variable, and a turbo actuator 29 that simultaneously changes the opening degrees of these variable vanes.

  The engine 1 also includes an EGR device 30. The EGR device 30 includes an EGR passage 31 for returning a part of exhaust gas (referred to as “EGR gas”) in the exhaust passage 4 (especially in the exhaust manifold 20) to the intake passage 3 (particularly in the intake manifold 10). The EGR cooler 32 that cools the EGR gas flowing through the EGR passage 31 and the EGR valve 33 for adjusting the flow rate of the EGR gas are provided.

  The control apparatus according to the present embodiment includes an electronic control unit (hereinafter referred to as “ECU”) 100 that forms a control unit or a controller. ECU 100 includes a CPU, a ROM, a RAM, an input / output port, a storage device, and the like. The ECU 100 controls the injector 7, the intake throttle valve 16, the addition valve 25, the EGR valve 33, the turbo actuator 29, and the like.

  The control device according to the present embodiment also includes the following sensors. Regarding these sensors, in addition to the air flow meter 13 described above, a rotational speed sensor 40 for detecting the rotational speed of the engine (specifically, the rotational speed per unit time (rpm)) and the accelerator opening degree are detected. The accelerator opening sensor 41 is provided. Further, exhaust temperature sensors 42, 43, 44, and 46 are provided for detecting exhaust temperatures (inlet gas temperatures) upstream or near the inlet of each of the oxidation catalyst 22, the DPF 23, the NOx catalyst 24, and the ammonia oxidation catalyst 26. ing. Further, a differential pressure sensor 45 for detecting a differential pressure between the exhaust pressure upstream and downstream of the DPF 23 is provided. Output signals from these sensors are sent to the ECU 100.

  Further, a boost pressure sensor 47 for detecting the supercharging pressure or boost pressure and a pressure sensor 48 for detecting the turbine inlet pressure are provided. Output signals from these sensors are also sent to the ECU 100. The boost pressure sensor 47 is installed in the intake pipe 11 downstream of the intake throttle valve 16 and immediately before the intake manifold 10 in this embodiment, but this installation position is arbitrary, for example, installed in the intake manifold 10. May be. In the present embodiment, the pressure sensor 48 is installed in the EGR passage 31 on the upstream side in the EGR gas flow direction of the EGR valve 33 and the EGR cooler 32, but this installation position may be on the upstream side of the turbine 14T (especially the nozzle). For example, it may be installed in the exhaust manifold 20. The turbine inlet pressure may be estimated based on a predetermined model.

  Next, the control of this embodiment will be described with reference to the control routine shown in FIG. The illustrated routine is repeatedly executed by the ECU 100 at every predetermined calculation cycle τ (for example, 10 msec).

  In step S101, the ECU 100 compares the engine speed Ne, the accelerator opening Ac, the boost pressure Pb, and the intake air amount Ga detected by the rotation speed sensor 40, the accelerator opening sensor 41, the boost pressure sensor 47, and the air flow meter 13, respectively. Get the value.

  In step S102, the ECU 100 determines the fuel injection amount, specifically, the command injection amount to the injector 7 according to a predetermined map as shown in FIG. 3A based on the engine speed Ne and the accelerator opening degree Ac. A target fuel injection amount Q is calculated.

  The engine speed Ne, the accelerator opening degree Ac, and the target fuel injection amount Q are all engine parameters that represent the operating state of the engine. The engine operating state is thus defined by at least one of these three engine parameters. Further, the accelerator opening degree Ac and the target fuel injection amount Q are both engine parameters corresponding to the engine load.

  Next, the ECU 100 calculates the target opening degree Sv of the variable vane 28 and the target opening degree Se of the EGR valve 33 in steps S103 to S106. These target openings Sv and Se are obtained by adding the feedforward (F / F) terms Svff and Seff and the feedback (F / B) terms Svfb and Sefb.

  The calculation methods of the target opening degrees Sv and Se are the same. First, the calculation method of the variable vane target opening degree Sv will be described in detail.

  In step S103, the ECU 100 calculates the F / F term Svff according to a predetermined map as shown in FIG. 3B based on the engine speed Ne and the target fuel injection amount Q.

  In step S104, the ECU 100 calculates the target boost pressure Pbt according to a predetermined map as shown in FIG. 3C based on the engine speed Ne and the target fuel injection amount Q.

  In step S105, the ECU 100 calculates the F / B term Svfb based on the difference between the target boost pressure Pbt and the actual boost pressure Pb acquired in step S101. Specifically, ECU 100 calculates a difference ΔPb = Pbt−Pb between target boost pressure Pbt and actual boost pressure Pb. Based on the difference ΔPb, the F / B term Svfb is calculated according to a predetermined map (not shown). When the difference ΔPb is positive, that is, when the actual boost pressure Pb is smaller than the target boost pressure Pbt, the negative F / B term Svfb on the boost pressure increasing side is calculated. Conversely, when the difference ΔPb is negative, that is, when the actual boost pressure Pb is larger than the target boost pressure Pbt, the positive F / B term Svfb on the boost pressure decrease side is calculated. In calculating the F / B term Svfb, it is preferable to set the total value of the P term, the I term, and the D term corresponding to the difference ΔPb as the F / B term Svfb in accordance with the PID control method.

  In step S106, the ECU 100 calculates the variable vane target opening Sv (= Svff + Svfb) by adding the calculated F / F term Svff and F / B term Svfb.

  Thus, the variable vane opening degree control is performed by a combination of the F / F control by the F / F term Svff and the F / B control by the F / B term Svfb. The F / F term Svff is a value that serves as a base for the variable vane target opening Sv, and is a value that can generally achieve the target boost pressure Pbt in the current engine operating state. On the other hand, the target boost pressure Pbt cannot always be realized only by the F / F term Svff, for example, because the actual engine operating state constantly changes. Therefore, the feedback term Svsb is added, and the variable vane opening is precisely controlled so that the target boost pressure Pbt can be stably realized.

  Next, a method for calculating the EGR valve target opening degree Se will be described.

  In step S103, the ECU 100 calculates the F / F term Seff based on the engine speed Ne and the target fuel injection amount Q according to a predetermined map as shown in FIG.

  In step S104, the ECU 100 calculates a target intake air amount Gat based on the engine speed Ne and the target fuel injection amount Q according to a predetermined map as shown in FIG.

  In step S105, the ECU 100 calculates the F / B term Sefb based on the difference between the target intake air amount Gat and the actual intake air amount Ga acquired in step S101. Specifically, the ECU 100 calculates a difference ΔGa = Gat−Ga between the target intake air amount Gat and the actual intake air amount Ga. Based on the difference ΔGa, the F / B term Sefb is calculated according to a predetermined map (not shown). When the difference ΔGa is positive, that is, when the actual intake air amount Ga is smaller than the target intake air amount Gat, the negative F / B term Sefb on the intake air amount increase side, that is, the EGR gas amount decrease side is calculated. Conversely, when the difference ΔGa is negative, that is, when the actual intake air amount Ga is larger than the target intake air amount Gat, the positive F / B term Sefb on the intake air amount decrease side, that is, the EGR gas amount increase side is calculated. . In calculating the F / B term Sefb, it is preferable to set the total value of the P term, the I term, and the D term according to the difference ΔGa as the F / B term Sefb in accordance with the PID control method.

  In step S106, the ECU 100 adds the calculated F / F term Seff and the F / B term Sefb to calculate the EGR valve target opening degree Se (= Seff + Sefb). In step S107, the ECU 100 controls the opening degree of the EGR valve 33 to the EGR valve target opening degree Se.

  As described above, the EGR valve opening degree control is also performed by a combination of the F / F control by the F / F term Seff and the F / B control by the F / B term Sefb. The F / F term Seff is a value that is a base of the EGR valve target opening degree Se, and is a value that can generally achieve the target EGR rate in the current engine operating state. On the other hand, the target EGR rate cannot always be realized only by the F / F term Seff, for example, because the actual engine operating state constantly changes. Therefore, the feedback term Sesb is added, and the EGR valve opening is precisely controlled so that the target EGR rate can be stably realized.

  Next, the ECU 100 calculates the minimum opening Svmin of the variable vane 28 in steps S108 to S110, and controls the opening of the variable vane 28 so as to be equal to or greater than the minimum opening Svmin in steps S111 to 113. That is, the minimum opening degree Svmin is a guard value that defines the lower limit of the variable vane opening degree. The reason for providing such a minimum opening degree Svmin is to avoid excessively reducing the opening degree of the variable vane 28 (over-throttle) due to transient operation conditions such as engine product variations and rapid acceleration. is there.

  As will be described later, in the present embodiment, smoke at the time of sudden acceleration is effectively reduced by optimally setting the minimum opening degree Svmin.

  In step S108, the ECU 100 calculates two types of variable vane minimum opening, that is, the first vane minimum opening Svmin1 and the second vane minimum opening Svmin2 based on the engine operating state. Specifically, the ECU 100 calculates the first vane minimum opening degree Svmin1 according to a predetermined map as shown in FIG. 4 (A) based on the engine speed Ne and the target fuel injection amount Q, and FIG. 4 (B). The second vane minimum opening Svmin2 is calculated according to a predetermined map as shown in FIG.

  The first vane minimum opening Svmin1 is set in advance on the assumption that the EGR valve 33 is originally closed, that is, the EGR valve 33 is fully closed and the opening is 0 (%). Minimum opening.

  On the other hand, the second vane minimum opening Svmin2 is based on the assumption that the EGR valve 33 is originally open, that is, the EGR valve 33 is not fully closed and the opening is larger than 0 (%). It is a preset minimum opening.

  The first vane minimum opening Svmin1 is a relatively small value. The reason is that the EGR valve 33 is assumed to be closed, and even if the variable vane opening is decreased and the exhaust pressure is increased, the problem of smoke deterioration due to excessive EGR gas amount does not occur. Conversely, the second vane minimum opening Svmin2 is a relatively large value. The reason is that the EGR valve 33 is assumed to be opened, and if the variable vane opening is decreased to increase the exhaust pressure, there is a possibility that a problem of smoke deterioration due to excessive EGR gas amount may occur.

  Therefore, in the same engine operating state (engine speed Ne and target fuel injection Q), the second vane minimum opening Svmin2 is larger than the first vane minimum opening Svmin1.

  Next, in step S109, the ECU 100 calculates a weight w (0 ≦ w ≦ 1) used in the subsequent weighted average according to the engine operating state and the EGR valve opening. Specifically, the ECU 100, as shown in FIG. 4C, is based on the engine speed Ne acquired in step S101, which is one of the engine parameters, and the EGR valve target opening degree Se calculated in step S106. The weight w is calculated according to a predetermined map.

  FIG. 5 shows an example of the value of the weight w when the engine speed Ne is a specific engine speed N1. As shown in the drawing, the weight w increases from 0.00 to 1.00 as the EGR valve target opening degree Se changes from 0 (%) to 100 (%). As will be described later, since the minimum opening degree Svmin is calculated by applying the second vane minimum opening degree Svmin2 as the weight w increases, the minimum opening degree Svmin tends to increase as the EGR valve target opening degree Se increases.

  Shown in the figure are the values of the grid points in the map of FIG. The weight w is maintained at 0.00 until the EGR valve target opening degree Se reaches 0 (%) to 30 (%), and the EGR valve target opening degree Se is changed from 30 (%) to 40 (%). As it increases, it increases continuously from 0.00 to 0.92. When the EGR valve target opening degree Se increases from 40 (%) to 50 (%), it continuously increases from 0.92 to 1.00, and the EGR valve target opening degree Se increases from 50 (%) to 100 ( %) Until it reaches 1.00.

  In addition, the numerical example described in this specification is an example, and is for the purpose of easy understanding only, and the numerical value itself has no meaning. The numerical values can naturally be changed, and there is no intention to limit the present invention to such numerical examples.

Next, in step S110, the ECU 100 calculates the variable vane minimum opening Svmin by weighted averaging the first vane minimum opening Svmin1 and the second vane minimum opening Svmin2 with the weight w. Specifically, ECU 100 calculates variable vane minimum opening degree Svmin according to the following equation (1).
Svmin = (1-w) × Svmin1 + w × Svmin2 (1)

  Next, in step S111, the ECU 100 compares the variable vane target opening Sv calculated in step S106 with the variable vane minimum opening Svmin. When Sv> Svmin, the routine proceeds to step S112, where the ECU 100 controls the opening degree of the variable vane 28 to the variable vane target opening degree Sv. That is, the turbo actuator 29 is controlled so that the actual opening of the variable vane 28 matches the variable vane target opening Sv.

  On the other hand, when Sv ≦ Svmin, the ECU 100 proceeds to step S113, and the ECU 100 controls the opening degree of the variable vane 28 to the variable vane minimum opening degree Svmin. That is, the turbo actuator 29 is controlled so that the actual opening of the variable vane 28 matches the variable vane minimum opening Svmin. Thereby, the opening degree of the variable vane 28 is limited to the variable vane minimum opening degree Svmin or more.

  6 and 7 show examples of numerical changes in the control of the present embodiment. In this example, the engine speed Ne is N1 and the target fuel injection Q is a specific value Q1. The first vane minimum opening degree Svmin1 and the second vane minimum opening degree Svmin2 are values obtained from the maps of FIGS. 4A and 4B, respectively.

  As shown in the drawing, the first vane minimum opening Svmin1 is constant at 15 (%), and the second vane minimum opening Svmin2 is constant at 25 (%). The weight w changes as shown in FIG. 5 according to the EGR valve target opening degree Se.

  As a result of calculating the variable vane minimum opening Svmin according to the equation (1), the variable vane minimum opening Svmin is the first vane until the EGR valve target opening Se reaches 20 (%) to 30 (%). It is held at 15.0 (%) equal to the minimum opening degree Svmin1. Further, the variable vane minimum opening degree Svmin continuously increases from 15.0 (%) to 24.2 (%) when the EGR valve target opening degree Se increases from 30 (%) to 40 (%). The variable vane minimum opening Svmin is equal to the second vane minimum opening Svmin2 from 24.2 (%) when the EGR valve target opening Se increases from 40 (%) to 50 (%). (%) Continuously increasing.

  In this way, the ECU 100 sets the minimum opening Svmin of the variable vane according to the engine operating state (engine speed Ne and target fuel injection amount Q) and the EGR valve opening (EGR valve target opening Se), and As shown when the EGR valve target opening degree Se is between 30 (%) and 50 (%), the minimum opening degree Svmin of the variable vane is continuously changed according to the opening degree of the EGR valve. In particular, the ECU 100 continuously increases the minimum opening Svmin of the variable vane according to the increase in the opening of the EGR valve.

  Next, the advantages of this embodiment will be described in comparison with a comparative example.

  In the comparative example, the variable vane minimum opening Svmin ′ is simply set to one of the first vane minimum opening Svmin1 and the second vane minimum opening Svmin2. That is, when the EGR valve 33 is closed, the first vane minimum opening Svmin1 obtained from the map of FIG. 4A is set to the variable vane minimum opening Svmin ′, and when the EGR valve 33 is opened, FIG. ) Is obtained as the variable vane minimum opening Svmin ′. The second vane minimum opening Svmin2 is larger than the first vane minimum opening Svmin1. Note that the value of the second vane minimum opening Svmin2 input to the map of FIG. 4B is different from the input value of this embodiment, and the same engine operating state (engine speed Ne and target fuel injection amount Q). Under this condition, a value equal to or smaller than the input value of the present embodiment is input.

  Therefore, in the comparative example, when setting the variable vane minimum opening degree Svmin ′, the magnitude of the EGR valve opening degree is not considered so much, and simply depends on whether it is zero (closed) or non-zero (opened). Only, the variable vane minimum opening degree Svmin ′ is switched and changed stepwise or alternatively. Specifically, when the EGR valve opening is zero, the variable vane minimum opening Svmin ′ is set to the first vane minimum opening Svmin1, and when the EGR valve opening is other than zero, the variable vane minimum opening Svmin ′ is larger. The second vane minimum opening Svmin2 is set.

  However, it turns out that the variable vane minimum opening degree Svmin ′ when the EGR valve 33 is opened is too small and the actual variable vane opening degree is reduced too much, and smoke is noticeably generated during sudden acceleration. did.

  FIG. 8 is a time chart comparing the results of control in this embodiment and the comparative example. The horizontal axis is time t. The vertical axis in FIG. 8A is the smoke discharge amount, the line g is for the comparative example, and the line h is for the present embodiment. The vertical axis in FIG. 8B is the actual EGR valve opening. Line e is for the comparative example, and line f is for the present embodiment, but they overlap. The vertical axis | shaft of FIG.8 (C) is a variable vane opening degree. Line a is the variable vane minimum opening Svmin ′ in the comparative example, line b is the actual opening of the variable vane in the comparative example, line c is the variable vane minimum opening Svmin in the present embodiment, and line d. Is the actual opening of the variable vane in this embodiment.

  In the case of the comparative example, when sudden acceleration starts at time t1, the actual opening degree of the variable vane (line b) is finally reduced to the variable vane minimum opening degree Svmin ′ (line a). However, since this variable vane minimum opening degree Svmin ′ is a value that is too small, a significant amount of smoke is generated as seen in the line g.

  On the other hand, in the case of this embodiment, after sudden acceleration starts at time t1, the actual opening of the variable vane (line d) is finally reduced to the variable vane minimum opening Svmin (line c). The However, since this variable vane minimum opening degree Svmin is larger than the variable vane minimum opening degree Svmin 'of the comparative example, the variable vane opening degree after reduction can be made larger than the comparative example. As a result, an excessive decrease in the variable vane opening can be prevented, and the amount of smoke discharged during sudden acceleration can be suppressed. As can be seen in FIG. 8A, the smoke discharge amount (line h) of the present embodiment can be more effectively reduced than the smoke discharge amount (line g) of the comparative example.

  As described above, according to the present embodiment, the variable vane minimum opening is not simply switched between two values when the EGR valve is closed and opened, but is changed according to the opening of the EGR valve. Since the vane minimum opening is continuously changed, the variable vane minimum opening can be optimally set in consideration of the EGR valve opening, and smoke at the time of sudden acceleration can be effectively reduced.

  In particular, according to this embodiment, since the variable vane minimum opening is continuously increased as the EGR valve opening increases, the variable vane minimum opening is also increased when the EGR valve opening is large during sudden acceleration. Thus, it is possible to prevent the variable vane opening from being excessively reduced and to effectively reduce smoke during sudden acceleration. Note that when the EGR valve opening is small during rapid acceleration, there is less risk of smoke deterioration, and therefore the boost pressure can be increased by reducing the variable vane minimum opening, thereby improving the acceleration performance.

  In addition, according to the present embodiment, the optimum variable vane minimum opening can be obtained only by adding the necessary logic (steps S109 and S110 in FIG. 2) using the maps of FIGS. 4A and 4B in the comparative example. The degree Svmin can be calculated, and the load and cost during development can be reduced.

  As mentioned above, although embodiment of this invention was described in detail, various embodiment of this invention can be considered variously.

  (1) For example, in step S109 of FIG. 2, the ECU 100 determines the engine based on the target fuel injection amount Q calculated in step S102 and the EGR valve target opening degree Se calculated in step S106, which are different engine parameters. The weight w may be calculated according to a predetermined map as shown in 4 (D). That is, the weight w may be a function of the fuel injection amount and the EGR valve opening.

  (2) The weight w may be calculated based on the engine speed Ne, the target fuel injection amount Q, and the EGR valve target opening degree Se, as shown in FIG. In this case, a map or function indicating the relationship between the four is stored in the ECU 100 in advance, and the ECU 100 calculates the weight w according to the map or function. In this case, the weight w is a function of the engine speed, the fuel injection amount, and the EGR valve opening.

  (3) In the above embodiment, the control of FIG. 2 is always performed. Alternatively, the control of FIG. 2 may be performed only when the engine is suddenly accelerated. In this case, the control of the comparative example can be performed, for example, except during the rapid acceleration.

  (4) As for the value of the EGR valve opening, when there is a sensor for detecting the actual opening of the EGR valve 33, a sensor detection value may be used instead of the EGR valve target opening Se.

  The embodiment of the present invention is not limited to the above-described embodiment, and includes all modifications, applications, and equivalents included in the concept of the present invention defined by the claims. Therefore, the present invention should not be construed as being limited, and can be applied to any other technique belonging to the scope of the idea of the present invention.

1 Internal combustion engine
14 Turbocharger 14T Turbine 28 Variable vane 30 EGR device 33 EGR valve 100 Electronic control unit (ECU)

Claims (3)

A control device for an internal combustion engine,
The internal combustion engine includes a variable displacement turbocharger having a variable vane and an EGR device having an EGR valve,
The control device includes a control unit configured to control the opening of the variable vane and the EGR valve,
The control unit sets the minimum opening of the variable vane based on the operating state of the internal combustion engine and the opening of the EGR valve, and the minimum opening of the variable vane according to the opening of the EGR valve. A control device for an internal combustion engine characterized by continuously changing the degree. The control device for an internal combustion engine according to claim 1, wherein the control unit continuously increases the minimum opening of the variable vane in accordance with an increase in the opening of the EGR valve. The control unit is
Calculating a first vane minimum opening, which is a variable vane minimum opening when the EGR valve is closed, based on an operating state of the internal combustion engine;
Calculating a second vane minimum opening, which is a variable vane minimum opening when the EGR valve is opened, based on an operating state of the internal combustion engine;
Calculating a weight based on the operating state of the internal combustion engine and the opening of the EGR valve;
3. The control device for an internal combustion engine according to claim 1, wherein the minimum opening of the variable vane is calculated by weighted averaging the first vane minimum opening and the second vane minimum opening by the weight.

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