JP2013079637A - Internal combustion engine control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine control device which can constantly find a target control amount satisfying constraints related to a control amount.SOLUTION: When the target control amount is to be changed to another target control amount Pb different form the current target control amount Pt, the internal combustion engine control device selects the control amount satisfying the constraints related to a control amount out of control amounts within the range specified based on a reference control amount by using the another target control amount as the reference control amount, sets the selected control amount to the target control amount, and controls the control amount in accordance with the target control amount that has been set. Moreover, the range is defined by a value exceeding the current target control amount and the reference control amount in a direction separate from the reference control amount.

Description

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

  Non-Patent Document 1 describes a so-called reference governor. In this reference governor, the target value of the control amount is determined as follows. That is, when the control amount is controlled according to the increased target control amount when the target value of the control amount (hereinafter, this target value is referred to as “target control amount”) is increased, A state relating to a controlled object that controls the controlled variable (hereinafter, this state is referred to as “controlled object state”) is predicted by model calculation. Then, it is determined whether or not the predicted control amount and the control target state satisfy a predetermined constraint.

  Here, when it is determined that the control amount and the control target state satisfy the constraints, the increased target control amount is a target control amount used for controlling the actual control amount (hereinafter, this target control amount is referred to as “ Actual control target control amount "). On the other hand, when it is determined that the control amount and the control target state do not satisfy the constraints, the increased target control amount (hereinafter, this target control amount is referred to as “original target control amount”) and before the increase is performed. When the control amount is controlled by using the control amount between the target control amount and the target control amount as the target control amount (hereinafter, this target control amount is referred to as “first corrected target control amount”). The state is predicted by model calculation. Then, it is determined whether or not the predicted control amount and the control target state satisfy the predetermined constraint.

  Here, when it is determined that the control amount and the control target state satisfy the constraints, the first corrected target control amount is set as a target control amount for actual control. On the other hand, when it is determined that the control amount and the control target state do not satisfy the constraint, the control amount between the first corrected target control amount and the original target control amount is a target control amount (hereinafter, this target control amount). In the case where the control amount is adopted as the “second correction target control amount”) and the control amount is controlled, the control amount and the control target state are predicted by the model calculation. Then, it is determined whether or not the predicted control amount and the control target satisfy the predetermined constraint.

  Thereafter, until it is determined that the control amount and the control target state satisfy the above constraints, as described above, the control amount and the control target when the new correction target control amount is adopted as the target control amount and the control amount is controlled. The state is predicted, and the corrected target control amount when it is determined that the predicted value of the control amount and the predicted value of the control target state satisfy the above constraints is set as the target control amount for actual control.

  In this way, according to the reference governor described in Non-Patent Document 1, as described above, the target control amount of the actual control amount is searched for such that the control amount and the control target state satisfy the constraints.

Automatica, 2002 (pages 2063-2073)

  By the way, according to the reference governor described in Non-Patent Document 1, the target control amount for actual control is only corrected so as to approach the original target control amount, and is separated from the original target control amount. It will not be corrected. For this reason, when the control amount or the control target state does not satisfy the above constraints while the control amount is being controlled toward the actual control target control amount, the control amount or the control target state is Even if a target control amount that satisfies the constraints is searched, a situation in which such a target control amount cannot be found may occur.

  Therefore, an object of the present invention is to provide a control device for an internal combustion engine that can always find out a target control amount that satisfies a restriction on the control amount.

  The present invention relates to a control device that controls a control amount related to an internal combustion engine. Then, the control device of the present invention is based on the reference control amount when the target control amount is to be changed to another target control amount different from the current target control amount. A control amount that satisfies the constraint on the control amount is selected from among the control amounts within a predetermined range, and the selected control amount is set as a target control amount, and the control amount is set according to the set target control amount. To control. In the present invention, the range is defined by a value exceeding the current target control amount in a direction away from the reference control amount, and the reference control amount.

  According to the present invention, the following effects can be obtained. That is, in the present invention, one of the limit values of a range (hereinafter, this range is also referred to as a “search range”) for searching for a target control amount that satisfies the restriction on the control amount in order to set the target control amount deviates from the reference control amount. The value exceeds the current target control amount in the direction. That is, in the present invention, the search range is expanded to a range beyond the current target control amount in a direction away from the reference control amount. Therefore, according to the present invention, even when the target control amount that satisfies the constraint on the control amount is not within the range between the reference control amount and the current target control amount, the control is performed within the expanded range. An effect is obtained that a target control amount that satisfies the constraint on the amount can be found. And according to this invention, the effect that control amount is controllable in the state which satisfy | filled restrictions regarding control amount is also acquired.

  Further, in another invention of the present application, in the above invention, a target control amount that satisfies the constraint from among target control amounts within the range based on a predicted value of the control amount ahead for a predetermined time from the present time. Is selected. In the present invention, the predicted value of the control amount ahead for a time longer than the time constant related to the change of the control amount, the predicted value of the control amount ahead of the predetermined time, and the value of the current control amount. The range is defined by a value exceeding the current target control amount in a direction away from the reference control amount by a value set based on the reference control amount and the reference control amount.

  According to the present invention, the following effects can be obtained. That is, the time constant related to the change in the control amount represents the behavior of the change in the control amount when the control amount is controlled to the changed target control amount. Here, in the present invention, one of the limit values of the search range is determined by using the predicted value of the control amount ahead for a time longer than the time constant related to the change of the control amount. Therefore, according to the present invention, it is possible to surely find out the target control amount that satisfies the restriction on the control amount from the control amount within the search range.

  Further, in still another invention of the present application, in the above invention, the difference between the predicted value of the control amount ahead of the predetermined control time by the predetermined time and the time constant of the control amount ahead of the time constant by the time longer than the time constant. A value exceeding the current target control amount in a direction away from the reference control amount by a value set based on the difference between the current control amount value and the predicted value of the previous control amount for a longer time, and The range is defined by the reference control amount.

It is the figure which showed the internal combustion engine to which the control apparatus of 1st Embodiment was applied. It is the figure which showed the vane of the supercharger of 1st Embodiment. It is the figure which showed the map used for acquisition of the reference | standard supercharging pressure of 1st Embodiment. It is a figure for demonstrating the setting procedure of the target supercharging pressure of 1st Embodiment in case a target supercharging pressure is increased. It is a figure for demonstrating the setting procedure of the target supercharging pressure of 1st Embodiment in case a target supercharging pressure is reduced. It is the figure which showed an example of the routine which performs the setting of the target supercharging pressure of 1st Embodiment. It is the figure which showed the internal combustion engine which can apply the control apparatus of this invention.

  Hereinafter, embodiments of the control device for an internal combustion engine of the present invention will be described. FIG. 1 shows an internal combustion engine to which the control device of the first embodiment of the present invention is applied. In the following description, “engine speed” means “the speed of the internal combustion engine”, “engine operation” means “the operation of the internal combustion engine”, and “engine operation state” means “the operation state of the internal combustion engine”. "Means.

  The internal combustion engine shown in FIG. 1 is a compression ignition type internal combustion engine (so-called diesel engine). In FIG. 1, 10 is an internal combustion engine, 20 is a main body of the internal combustion engine 10, 21 is a fuel injection valve, 22 is a fuel pump, 23 is a fuel supply passage, 30 is an intake passage, 31 is an intake manifold, 32 is an intake pipe, 33 Is a throttle valve, 34 is an intercooler, 35 is an air flow meter, 36 is an air cleaner, 37 is a supercharging pressure sensor, 40 is an exhaust passage, 41 is an exhaust manifold, 42 is an exhaust pipe, 60 is a supercharger, and 70 is an accelerator pedal. , 71 denotes an accelerator pedal depression amount sensor, 72 denotes a crank position sensor, and 80 denotes an electronic control device. The intake passage 30 includes an intake manifold 31 and an intake pipe 32. The exhaust passage 40 includes an exhaust manifold 41 and an exhaust pipe 42.

  The electronic control unit 80 is composed of a microcomputer. The electronic control unit 80 includes a CPU (microprocessor) 81, a ROM (read only memory) 82, a RAM (random access memory) 83, a backup RAM 84, and an interface 85. The CPU 81, ROM 82, RAM 83, backup RAM 84, and interface 85 are connected to each other by a bidirectional bus.

  The fuel injection valve 21 is attached to the main body 20 of the internal combustion engine. A fuel pump 22 is connected to the fuel injection valve 21 via a fuel supply passage 23. The fuel pump 22 supplies high-pressure fuel to the fuel injection valve 21 via the fuel supply passage 23. The fuel injection valve 21 is electrically connected to the interface 85 of the electronic control device 80. The electronic control unit 80 supplies a command signal for causing the fuel injection valve 21 to inject fuel to the fuel injection valve 21. The fuel pump 22 is also electrically connected to the interface 85 of the electronic control device 80. The electronic control unit 80 supplies the fuel pump 22 with a control signal for controlling the operation of the fuel pump 22 so that the pressure of the fuel supplied from the fuel pump 22 to the fuel injection valve 21 is maintained at a predetermined pressure. . The fuel injection valve 21 is attached to the main body 20 of the internal combustion engine so that its fuel injection hole is exposed in the combustion chamber. Therefore, when a command signal is supplied from the electronic control unit 80 to the fuel injection valve 21, the fuel injection valve 21 directly injects fuel into the combustion chamber.

  The intake manifold 31 is branched into a plurality of pipes at one end thereof, and these branched pipes are connected to intake ports (not shown) formed respectively corresponding to the combustion chambers of the main body 20 of the internal combustion engine. Has been. The intake manifold 31 is connected to one end of the intake pipe 32 at the other end.

  The exhaust manifold 41 is branched into a plurality of pipes at one end thereof, and these branched pipes are connected to exhaust ports (not shown) formed respectively corresponding to the combustion chambers of the main body 20 of the internal combustion engine. Has been. The exhaust manifold 41 is connected to one end of the exhaust pipe 42 at the other end.

  The throttle valve 33 is disposed in the intake pipe 32. Further, when the opening of the throttle valve 33 (hereinafter referred to as “throttle valve opening”) is changed, the flow passage area in the intake pipe 32 in the region where the throttle valve 33 is disposed changes. As a result, the amount of air passing through the throttle valve 33 changes, and as a result, the amount of air taken into the combustion chamber changes. The throttle 33 is electrically connected to the interface 85 of the electronic control device 80. The electronic control unit 80 supplies a control signal for operating the throttle valve 33 to the throttle valve 33.

  The intercooler 34 is disposed in the intake pipe 32 upstream of the throttle valve 33. The intercooler 34 cools the air flowing into the intercooler 34.

  The air flow meter 35 is disposed in the intake pipe 32 upstream of the intercooler 34. The air flow meter 35 is electrically connected to the interface 85 of the electronic control device 80. The air flow meter 35 outputs an output value corresponding to the amount of air passing therethrough. This output value is input to the electronic control unit 80. Based on this output value, the electronic control unit 80 calculates the amount of air passing through the air flow meter 35, that is, the amount of air taken into the combustion chamber.

  The supercharging pressure sensor 37 is disposed in the intake passage 30 (more specifically, the intake manifold 31) downstream of the throttle valve 33. The supercharging pressure sensor 37 is electrically connected to the interface 85 of the electronic control device 80. The supercharging pressure sensor 37 outputs an output value corresponding to the pressure of the surrounding gas (that is, the pressure of the gas in the intake manifold 31 and the pressure of the gas sucked into the combustion chamber). Based on this output value, the electronic control unit 80 calculates the pressure of the gas around the supercharging pressure sensor 37, that is, the pressure of the gas sucked into the combustion chamber (hereinafter, this gas is referred to as “supercharging pressure”).

  The supercharger 60 has a compressor 60C and an exhaust turbine 60T. The supercharger 60 can increase the pressure of the gas by compressing the gas sucked into the combustion chamber. The compressor 60 </ b> C is disposed in the intake passage 30 (more specifically, the intake pipe 32) upstream of the intercooler 34. The exhaust turbine 60T is disposed in the exhaust passage 40 (more specifically, the exhaust pipe 42). As shown in FIG. 2, the exhaust turbine 60T includes an exhaust turbine body 60B and a plurality of blade-like vanes 60V. The compressor 60C and the exhaust turbine 60T (more specifically, the exhaust turbine body 60B) are connected by a shaft (not shown), and when the exhaust turbine is rotated by exhaust gas, the rotation of the exhaust turbine is reduced. It is transmitted to the compressor 60C by the shaft, and thereby the compressor 60C is rotated. Note that the gas in the intake passage 30 downstream of the compressor is compressed by the rotation of the compressor 60C, and as a result, the pressure of the gas is increased.

  On the other hand, the vanes 60V are radially arranged at equiangular intervals around the rotation center axis R1 of the exhaust turbine body so as to surround the exhaust turbine body 60B. Each vane 60V is arranged so as to be rotatable around a corresponding axis indicated by reference numeral R2 in FIG. The direction in which each vane 60V extends (that is, the direction indicated by symbol E in FIG. 2) is referred to as an “extending direction”, and the rotation center axis R1 of the exhaust turbine body 60B and the rotation of the vane 60V are referred to as “extension direction”. When a line (namely, a line indicated by a symbol A in FIG. 2) connecting the moving axis line R2 is referred to as a “reference line”, each vane 60V has its extending direction E and the corresponding reference line A and Are rotated so that the angles formed by the two are equal for all the vanes 60V. Then, each vane 60V is rotated so that the angle formed between the extending direction E and the corresponding reference line A is small, that is, the flow area between adjacent vanes 60V is small. The pressure in the exhaust passage 40 upstream of the exhaust turbine main body 60B (hereinafter, this pressure is referred to as “exhaust pressure”) increases, and as a result, the flow rate of the exhaust gas supplied to the exhaust turbine main body 60B increases. For this reason, the rotational speed of the exhaust turbine body 60B is increased, and as a result, the rotational speed of the compressor 60C is also increased. Therefore, the gas flowing in the intake passage 30 is greatly compressed by the compressor 60C. For this reason, the gas flowing through the intake passage 30 is compressed by the compressor 60C as the angle between the extending direction E of each vane 60V and the reference line corresponding thereto (hereinafter, this angle is referred to as “vane opening”) becomes smaller. (That is, the supercharging pressure increases).

  The vane 60V is electrically connected to the interface 85 of the electronic control unit 80. The electronic control unit 80 supplies a control signal for operating the vane 60V to the vane 60V.

  An accelerator pedal depression amount sensor 71 is connected to the accelerator pedal 70. The accelerator pedal depression amount sensor 71 is electrically connected to the interface 85 of the electronic control unit 80. The accelerator pedal depression amount sensor 71 outputs an output value corresponding to the depression amount of the accelerator pedal 70. This output value is input to the electronic control unit 80. The electronic control unit 80 calculates the amount of depression of the accelerator pedal 70 and thus the torque required for the internal combustion engine (hereinafter, this torque is referred to as “requested engine torque”) based on the output value.

  The crank position sensor 72 is disposed in the vicinity of a crankshaft (not shown) of the internal combustion engine. The crank position sensor 72 is electrically connected to the interface 85 of the electronic control unit 80. The crank position sensor 72 outputs an output value corresponding to the rotational phase of the crankshaft. This output value is input to the electronic control unit 80. The electronic control unit 80 calculates the engine speed based on this output value.

  Next, the vane control according to the first embodiment will be described. In the following description, “target boost pressure” means “target value of boost pressure”. In the first embodiment, the supercharging pressure deviation is reduced and the supercharging pressure is set based on the deviation of the actual supercharging pressure at that time with respect to the target supercharging pressure (hereinafter, this deviation is referred to as “supercharging pressure deviation”). A control signal to be supplied to the vane is calculated to converge to the target supercharging pressure with the change characteristic of the period. The calculated control signal is supplied to the vane. That is, in the first embodiment, the vane is feedback-controlled based on the target boost pressure.

  Next, the setting of the target boost pressure according to the first embodiment will be described. In the first embodiment, the optimum supercharging pressure is obtained in advance by experiments or the like according to the engine operating state defined by the engine speed and the required engine torque. The obtained supercharging pressure is stored in the electronic control unit as a reference supercharging pressure Pb in the form of a function map of the engine speed NE and the required engine torque TQ as shown in FIG. . Then, during engine operation, the reference boost pressure Pb corresponding to the current engine speed NE and the required engine torque TQ at that time is acquired from the map of FIG. In the map of FIG. 3, the reference boost pressure Pb increases as the engine speed NE increases, and the reference boost pressure Pb increases as the required engine torque TQ increases. In the first embodiment, a supercharging pressure constraint (hereinafter simply referred to as “constraint”) is predetermined.

  Then, when there is a need to change the target supercharging pressure from the current target supercharging pressure because the engine speed or the required engine torque has changed, it corresponds to the engine speed at that time and the required engine torque at that time. The reference boost pressure is obtained from the map of FIG. Then, a range defined by the acquired reference supercharging pressure and a supercharging pressure exceeding the current target supercharging pressure in a direction away from the reference supercharging pressure by a predetermined value is set as a search range. When the vane is controlled by adopting the supercharging pressure at the center of the search range as the provisional target supercharging pressure (hereinafter referred to as the provisional target supercharging pressure) The preceding supercharging pressure is predicted as the predicted supercharging pressure for a predetermined time.

  Here, when the predicted predicted boost pressure (hereinafter, this predicted boost pressure is referred to as “first predicted boost pressure”) satisfies the constraint, the reference boost pressure and the adopted temporary target boost pressure are Is used as a new search range, and the supercharging pressure at the center of the search range is adopted as the provisional target supercharging pressure. The supply pressure is predicted as a new predicted supercharging pressure.

  On the other hand, when the first predicted supercharging pressure satisfies the constraint, the range defined by the current target supercharging pressure and the temporary target supercharging pressure is adopted as a new search range, and the supercharge at the center of the search range is adopted. The previous supercharging pressure is predicted as a new predicted supercharging pressure for the predetermined time when the supply pressure is adopted as the temporary target supercharging pressure and the vane is controlled.

  After that, when the predicted boost pressure that is predicted based on the newly adopted provisional target boost pressure does not satisfy the constraints, it is between the provisional target boost pressure at that time and the current target boost pressure. The range defined by the provisional target supercharging pressure that is closest to the temporary target supercharging pressure at that time and the provisional target supercharging pressure at that time among the provisional target supercharging pressures that were previously adopted as a new search range Adopting the supercharging pressure at the center of the search range as a new provisional target supercharging pressure and predicting the supercharging pressure ahead by the predetermined time when the vane is controlled, and predicting by this A determination is made as to whether or not the predicted boost pressure that has been satisfied satisfies the constraint.

  On the other hand, when the predicted boost pressure that is predicted based on the newly adopted provisional target boost pressure does not satisfy the constraints, it is adopted first between the provisional target boost pressure at that time and the current boost pressure. The range defined by the provisional target boost pressure closest to the provisional target boost pressure at that time and the provisional target boost pressure at that time is adopted as a new search range. When the supercharging pressure at the center of the search range is adopted as the new provisional target supercharging pressure and the vane is controlled, the supercharging pressure is predicted only for the predetermined time, and the predicted overpressure predicted thereby A determination is made as to whether the supply pressure satisfies the constraint.

  The search range is gradually narrowed each time the above prediction and the above determination are performed. When the search range becomes narrower than a predetermined range, the supercharging pressure at the center of the search range is set as a target supercharging pressure that is actually used for vane control. That is, the above-described prediction and the above-described determination are repeatedly performed until the search range becomes narrower than a predetermined range.

  That is, in the first embodiment, when the target supercharging pressure is to be changed to another target supercharging pressure different from the current target supercharging pressure, this other target supercharging pressure is used as the reference supercharging pressure. From among the boost pressures within a range determined based on the reference boost pressure (that is, the search range), a boost pressure that satisfies the constraints on the boost pressure is selected, and the selected boost pressure is the target boost pressure. The boost pressure is set, and the boost pressure is controlled according to the set target boost pressure. Here, in the first embodiment, the range (that is, the search range) is defined by a value exceeding the current target boost pressure in a direction away from the reference boost pressure, and the reference boost pressure.

  Next, a specific example of setting the target boost pressure described above will be described. When it becomes necessary to change the target supercharging pressure from the current target supercharging pressure because the engine speed or the required engine torque has changed, the reference overpressure corresponding to the engine speed at that time and the required engine torque at that time The supply pressure Pb is acquired from the map of FIG. When the acquired reference supercharging pressure Pb is larger than the current target supercharging pressure (that is, when it is necessary to increase the target supercharging pressure from the current target supercharging pressure), The target boost pressure is set as follows.

  That is, as shown in FIG. 4A, the current target boost pressure Pt is set to a predetermined value β in the direction away from the acquired reference boost pressure Pb and the reference boost pressure Pb. And a range defined by a supercharging pressure Pt−β that exceeds the current target supercharging pressure Pt (that is, a value that is smaller by a predetermined value β than the current target supercharging pressure Pt) (ie, hatched in FIG. 4A) Is used as a search range, and the supercharging pressure P1 at the center of the search range is used as a temporary target supercharging pressure (hereinafter, this temporary target supercharging pressure is referred to as "first temporary target supercharging pressure"). The supercharging pressure ahead for a predetermined time when the vane is controlled by being adopted is predicted as the predicted supercharging pressure (hereinafter, this predicted supercharging pressure is referred to as “first predicted supercharging pressure”). A determination is made as to whether the first predicted boost pressure satisfies the constraint.

  Here, when the first predicted supercharging pressure satisfies the constraint, as shown in FIG. 4B, a range defined by the reference supercharging pressure Pb and the first provisional target supercharging pressure P1. (That is, a range indicated by hatching in FIG. 4B) is adopted as a new search range, and the supercharging pressure P2 at the center of the search range is set as a provisional target supercharging pressure (hereinafter, this provisional target supercharging pressure). As the “second provisional target supercharging pressure”), the supercharging pressure ahead of the predetermined time when the vane is controlled becomes a new predicted supercharging pressure (hereinafter, this predicted supercharging pressure). Is referred to as “second predicted boost pressure”), and a determination is made as to whether or not this second predicted boost pressure satisfies the constraint.

  Here, when the second predicted supercharging pressure satisfies the constraint, as shown in FIG. 4C, a range defined by the reference supercharging pressure Pb and the second provisional target supercharging pressure P2. The vane is controlled by adopting the new search range (that is, the range shown by hatching in FIG. 4C) and using the supercharging pressure P3 at the center of the search range as the temporary target supercharging pressure. The previous supercharging pressure is predicted as a new predicted supercharging pressure for the predetermined time at this time, and it is determined whether or not this predicted supercharging pressure satisfies the constraint. Thereafter, the prediction of the predicted boost pressure and the determination of whether or not the predicted boost pressure satisfies the constraints are repeatedly performed, and finally, at least, it is indicated by hatching in FIG. The boost pressure within the search range is set to the target boost pressure actually used for vane control.

  On the other hand, when the second predicted supercharging pressure does not satisfy the constraints, as shown in FIG. 4D, the first temporary target supercharging pressure P2 and the second temporary target supercharging pressure P2 are used. A prescribed range (that is, a range indicated by hatching in FIG. 4D) is adopted as a new search range, and a supercharging pressure P4 at the center of the search range is adopted as a provisional target supercharging pressure. The previous supercharging pressure is predicted as a new predicted supercharging pressure for the predetermined time when the vane is controlled, and it is determined whether or not this predicted supercharging pressure satisfies the constraint. Thereafter, the prediction of the predicted boost pressure and the determination of whether or not the predicted boost pressure satisfies the constraints are repeatedly performed, and finally, at least, it is indicated by hatching in FIG. The boost pressure within the search range is set to the target boost pressure actually used for vane control.

  Further, when the first predicted supercharging pressure does not satisfy the constraint, as shown in FIG. 4E, it is defined by the current target supercharging pressure Pt and the first provisional target supercharging pressure P1. Range (that is, a range indicated by hatching in FIG. 4E) is used as a new search range, and the supercharging pressure P5 at the center of the search range is set as the provisional target supercharging pressure (hereinafter referred to as this provisional target overpressure). When the vane is controlled by adopting the supply pressure as “fifth provisional target boost pressure”), the previous boost pressure is changed to a new predicted boost pressure (hereinafter, this predicted boost pressure) for the predetermined time. The supply pressure is predicted as “the fifth predicted supercharging pressure”), and it is determined whether or not the fifth predicted supercharging pressure satisfies the constraint.

  Here, when the fifth predicted supercharging pressure does not satisfy the constraint, it is defined by the current target supercharging pressure Pt and the fifth provisional target supercharging pressure P5 as shown in FIG. The range to be used (that is, the range indicated by hatching in FIG. 4F) is adopted as the new search range, and the supercharging pressure P6 at the center of the search range is adopted as the temporary target supercharging pressure. The previous supercharging pressure is predicted as a new predicted supercharging pressure for the predetermined time when the engine is controlled, and it is determined whether or not this predicted supercharging pressure satisfies the constraint. Thereafter, the prediction of the predicted boost pressure and the determination of whether or not the predicted boost pressure satisfies the constraints are repeatedly performed, and finally, at least, it is indicated by hatching in FIG. The boost pressure within the search range is set to the target boost pressure actually used for vane control.

  On the other hand, when the fifth predicted supercharging pressure satisfies the constraint, as shown in FIG. 4G, it is defined by the fifth temporary target supercharging pressure P1 and the first temporary target supercharging pressure P1. The range to be used (that is, the range indicated by hatching in FIG. 4G) is adopted as the new search range, and the supercharging pressure P7 at the center of the search range is adopted as the provisional target supercharging pressure. The previous supercharging pressure is predicted as a new predicted supercharging pressure for the predetermined time when the engine is controlled, and it is determined whether or not this predicted supercharging pressure satisfies the constraint. Thereafter, the prediction of the predicted boost pressure and the determination of whether or not the predicted boost pressure satisfies the constraints are repeatedly performed, and finally, at least, it is indicated by hatching in FIG. The boost pressure within the search range is set to the target boost pressure actually used for vane control.

  On the other hand, when the acquired reference supercharging pressure Pb is smaller than the current target supercharging pressure (that is, when it is necessary to reduce the target supercharging pressure from the current target supercharging pressure), The target boost pressure is set as follows.

  That is, as shown in FIG. 5 (A), the acquired reference supercharging pressure Pb and the current target supercharging pressure Pt in a direction away from the reference supercharging pressure Pb are set to a predetermined value β. A range defined by a supercharging pressure exceeding the current target supercharging pressure Pt (that is, a value larger than the current target supercharging pressure Pt by a predetermined value β) Pt + β (that is, shown by hatching in FIG. 5A) Is used as the search range, and the supercharging pressure P8 at the center of the search range is used as the temporary target supercharging pressure (hereinafter, this temporary target supercharging pressure is referred to as "eighth temporary target supercharging pressure"). Then, the supercharging pressure ahead for a predetermined time when the vane is controlled is predicted as the predicted supercharging pressure (hereinafter, this predicted supercharging pressure is referred to as “eighth predicted supercharging pressure”). A determination is made as to whether or not the predicted boost pressure satisfies the constraint.

  Here, when the eighth predicted supercharging pressure satisfies the constraint, as shown in FIG. 5B, a range defined by the reference supercharging pressure Pb and the eighth provisional target supercharging pressure P8. (That is, a range indicated by hatching in FIG. 5B) is adopted as a new search range, and a supercharging pressure P9 at the center of the search range is set as a provisional target supercharging pressure (hereinafter, this provisional target supercharging pressure). As the “9th provisional target boost pressure”), and the vane is controlled, the previous boost pressure is changed to a new predicted boost pressure (hereinafter, this predicted boost pressure) for the predetermined time. Is determined as “the ninth predicted supercharging pressure”), and it is determined whether or not the ninth predicted supercharging pressure satisfies the constraint.

  Here, when the ninth predicted supercharging pressure satisfies the constraint, as shown in FIG. 5C, a range defined by the reference supercharging pressure Pb and the ninth provisional target supercharging pressure P9. The vane is controlled by adopting a new search range (that is, a range indicated by hatching in FIG. 5C) and using the supercharging pressure P10 at the center of the search range as the temporary target supercharging pressure. The previous supercharging pressure is predicted as a new predicted supercharging pressure for the predetermined time at this time, and it is determined whether or not this predicted supercharging pressure satisfies the constraint. Thereafter, the prediction of the predicted boost pressure and the determination of whether or not the predicted boost pressure satisfies the constraints are repeatedly performed, and finally, at least, it is indicated by hatching in FIG. The boost pressure within the search range is set to the target boost pressure actually used for vane control.

  On the other hand, when the ninth predicted supercharging pressure does not satisfy the constraint, as shown in FIG. 5D, the eighth temporary target supercharging pressure P9 and the eighth temporary target supercharging pressure P9 A prescribed range (that is, a range indicated by hatching in FIG. 5D) is adopted as a new search range, and a supercharging pressure P11 at the center of the search range is adopted as a provisional target supercharging pressure. The previous supercharging pressure is predicted as a new predicted supercharging pressure for the predetermined time when the vane is controlled, and it is determined whether or not this predicted supercharging pressure satisfies the constraint. Thereafter, the prediction of the predicted boost pressure and the determination of whether or not the predicted boost pressure satisfies the constraints are repeatedly performed, and finally, at least, it is indicated by hatching in FIG. The boost pressure within the search range is set to the target boost pressure actually used for vane control.

  Further, when the eighth predicted supercharging pressure does not satisfy the constraint, as shown in FIG. 5E, it is defined by the current target supercharging pressure Pt and the eighth provisional target supercharging pressure P8. Range (that is, the range indicated by hatching in FIG. 5E) is used as a new search range, and the supercharging pressure P12 at the center of the search range is set as the temporary target supercharging pressure (hereinafter referred to as this temporary target overpressure). When the vane is controlled by adopting the charging pressure as “a twelfth provisional target supercharging pressure”), the previous supercharging pressure is changed to a new predicted supercharging pressure (hereinafter, this predicted supercharging pressure) for the predetermined time. The supply pressure is predicted as “a twelfth predicted boost pressure”), and it is determined whether or not the twelfth predicted boost pressure satisfies the constraint.

  Here, when the twelfth predicted supercharging pressure does not satisfy the constraint, it is defined by the current target supercharging pressure Pt and the twelfth provisional target supercharging pressure P12 as shown in FIG. The range to be used (that is, the range shown by hatching in FIG. 5F) is adopted as a new search range, and the supercharging pressure P13 at the center of the search range is adopted as the provisional target supercharging pressure. The previous supercharging pressure is predicted as a new predicted supercharging pressure for the predetermined time when the engine is controlled, and it is determined whether or not this predicted supercharging pressure satisfies the constraint. Thereafter, the prediction of the predicted boost pressure and the determination of whether or not the predicted boost pressure satisfies the constraints are repeatedly performed, and finally, at least, it is indicated by hatching in FIG. The boost pressure within the search range is set to the target boost pressure actually used for vane control.

  On the other hand, when the twelfth predicted supercharging pressure satisfies the constraint, it is defined by the twelfth provisional target supercharging pressure P12 and the eighth provisional target supercharging pressure P8, as shown in FIG. The range to be used (that is, the range shown by hatching in FIG. 5G) is adopted as the new search range, and the supercharging pressure P14 at the center of the search range is adopted as the temporary target supercharging pressure. The previous supercharging pressure is predicted as a new predicted supercharging pressure for the predetermined time when the engine is controlled, and it is determined whether or not this predicted supercharging pressure satisfies the constraint. Thereafter, the prediction of the predicted supercharging pressure and the determination of whether the predicted supercharging pressure satisfies the constraints are repeatedly performed, and finally, at least, it is indicated by hatching in FIG. The boost pressure within the search range is set to the target boost pressure actually used for vane control.

  According to the first embodiment, the following effects can be obtained. That is, in the first embodiment, in order to set the target supercharging pressure, one of the limit values of the range in which the target supercharging pressure that satisfies the constraint on the supercharging pressure is searched is shifted in the direction away from the reference supercharging pressure. The value exceeds the supply pressure. In other words, in the first embodiment, the range for searching for the target boost pressure that satisfies the constraint on the boost pressure is expanded to the range beyond the current target boost pressure in a direction away from the reference boost pressure. Therefore, according to the first embodiment, even if the target boost pressure that satisfies the constraint on the boost pressure is not within the range between the reference boost pressure and the current target boost pressure, the expansion The effect that the target boost pressure satisfying the constraint on the boost pressure can be found within the determined range is obtained. And according to 1st Embodiment, the effect that a supercharging pressure can be controlled in the state which satisfy | filled the restrictions regarding a supercharging pressure is also acquired.

  In the first embodiment, it is determined whether or not the predicted supercharging pressure satisfies the constraint. However, in the first embodiment, in addition to the determination of whether the predicted supercharging pressure satisfies the constraint, the state of the supercharger when the supercharging pressure is controlled to the changed target supercharging pressure (for example, The state of the vane, the exhaust turbine, the compressor, or the like) may be predicted, and it may be determined whether or not the predicted state of the turbocharger satisfies a restriction regarding the state of the supercharger.

  Moreover, as a method for executing the setting of the target boost pressure described above, for example, a so-called reference governor can be used.

  Next, an example of a routine for performing the setting of the target boost pressure according to the first embodiment will be described. An example of this routine is shown in FIG. Note that this routine is started every time a predetermined crank angle arrives.

  When the routine of FIG. 6 is started, first, at step 100, the engine speed NE at that time and the required engine torque TQ at that time are acquired. Next, at step 101, the reference boost pressure Pb corresponding to the engine speed NE and the required engine torque TQ acquired at step 100 is acquired from the map of FIG. Next, at step 102, the reference boost pressure Pb acquired at step 101 is larger than the current target boost pressure Pt (Pb> Pt), or the reference boost pressure Pb acquired at step 101 is the current It is determined whether or not it is smaller than the target boost pressure Pt (Pb <Pt). Here, when it is determined that Pb> Pt or Pb <Pt, the routine proceeds to step 103. On the other hand, when it is determined that Pb> Pt or Pb <Pt is not satisfied, the routine ends as it is.

  In step 103, the target boost pressure Pp that satisfies the constraints as described above is searched. Next, at step 104, the target boost pressure Pp searched at step 103 is set to the target boost pressure Pt, and then the routine ends.

  By the way, in the first embodiment, the first search range is defined by the reference boost pressure and the boost pressure that exceeds the current target boost pressure by a predetermined value in a direction away from the reference boost pressure. The Here, the predetermined value may be any value as long as the value is greater than zero. For example, a value set as follows can be adopted as the predetermined value. That is, as the predetermined value, a time longer than a time constant related to a change in the supercharging pressure when the supercharging pressure is controlled to the changed target supercharging pressure (hereinafter, this time is simply referred to as “time constant”). A value that is set based on the predicted value of the supercharging pressure that is ahead for a predetermined period of time), the predicted value of the supercharging pressure that is ahead for the predetermined time, and the current supercharging pressure value Can be adopted.

  In this case, the set value may be any value as long as the value is set based on the predicted value and the current supercharging pressure value. For example, a value set as follows can be adopted as this value. That is, as this value, the difference between the predicted value of the supercharging pressure ahead by the predetermined time with respect to the predicted value of the supercharging pressure ahead by the time longer than the time constant (hereinafter, this difference is referred to as “first predicted value deviation”). )) And the difference in the current supercharging pressure with respect to the predicted value of the supercharging pressure that is longer than the time constant (hereinafter, this difference is referred to as “second predicted value deviation”). A value can be adopted.

  In this case, the set value may be any value as long as the value is set based on the first predicted value deviation and the second predicted value deviation. For example, the ratio of the first predicted value deviation to the second predicted value deviation can be used as this value.

  Further, the time longer than the time constant may be any time as long as it is longer than the time constant related to the change in the supercharging pressure when the supercharging pressure is controlled to the changed target supercharging pressure. . For example, a time that is three times the time constant can be adopted as this time.

  Thus, as the predetermined value, the predicted value of the supercharging pressure ahead for a time longer than the time constant, the predicted value of the supercharging pressure ahead for the predetermined time, and the current supercharging If the value set based on the pressure value is adopted, the following effects can be obtained. That is, the time constant related to the change in the supercharging pressure represents the behavior of the change in the supercharging pressure when the supercharging pressure is controlled to the changed target supercharging pressure. Therefore, it is possible to surely find out the target boost pressure that satisfies the constraint on the boost pressure from the boost pressure within the search range. Further, when the predetermined time is shorter than the time longer than the time constant, there is a high possibility that an error occurs in the predicted value of the preceding supercharging pressure for the predetermined time. However, in this case, since the search range is further expanded, the target boost pressure is set with certainty so that the boost pressure does not break the constraint. On the other hand, when the predetermined time is shorter than the time constant, it is unlikely that an error will occur in the predicted value of the preceding supercharging pressure for the predetermined time, and therefore the supercharging pressure breaks the constraint. Although the possibility is low, in this case, since the expansion of the search range becomes small, the target boost pressure that ensures that the boost pressure does not break the constraints is set reliably, and the calculation required for setting the target boost pressure The load is reduced.

  In addition, although embodiment mentioned above is embodiment at the time of applying this invention to the setting of target supercharging pressure, this invention is applicable also to the internal combustion engine shown by FIG. That is, in the internal combustion engine shown in FIG. 7, reference numeral 50 denotes an exhaust gas recirculation device (hereinafter, this device is referred to as “EGR device”). The EGR device 50 includes an exhaust gas recirculation pipe (hereinafter referred to as “EGR pipe”) 51, an exhaust gas recirculation control valve (hereinafter referred to as “EGR control valve”) 52, and an exhaust gas recirculation cooler. (Hereinafter, this cooler is referred to as an “EGR cooler”) 53. The EGR device 50 can introduce the exhaust gas discharged from the combustion chamber into the exhaust passage 40 into the intake passage 30 via the EGR pipe 51. The EGR pipe 51 is connected to the exhaust passage 40 (more specifically, the exhaust manifold 41) at one end, and connected to the intake passage 30 (more specifically, the intake manifold 31) at the other end. Yes. That is, the EGR pipe 51 connects the exhaust passage 40 to the intake passage 30.

  The EGR control valve 52 is disposed in the EGR pipe 51. When the opening degree of the EGR control valve 52 (hereinafter, this opening degree is referred to as “EGR control valve opening degree”) is changed, the amount of exhaust gas passing through the EGR control valve 52 is changed. The amount of exhaust gas introduced into the combustion chamber changes. The EGR control valve 52 is electrically connected to the interface 85 of the electronic control device 80. The electronic control unit 80 supplies a control signal for operating the EGR control valve 52 to the EGR control valve. The EGR cooler 53 is disposed in the EGR pipe 51. The EGR cooler 53 cools the exhaust gas flowing through the EGR pipe 51.

  In the internal combustion engine described above, the present invention can also be applied when setting the target value of the EGR rate (that is, the ratio of the amount of exhaust gas introduced into the combustion chamber to the amount of gas sucked into the combustion chamber). .

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 30 ... Intake passage, 40 ... Exhaust passage, 50 ... Exhaust gas recirculation device (EGR device), 52 ... Exhaust gas recirculation control valve (EGR control valve), 60 ... Supercharger, 60C ... Compressor, 60T ... Exhaust turbine, 60V ... Vane, 80 ... Electronic control device

Claims (3)

A control device for controlling a control amount related to an internal combustion engine,
When the target control amount is to be changed to another target control amount different from the current target control amount, the control amount is within a range determined based on the reference control amount with the other target control amount as the reference control amount In the control device that selects a control amount that satisfies the constraint on the control amount from among the control amount, sets the selected control amount as a target control amount, and controls the control amount according to the set target control amount,
A control device defined by a value that exceeds a current target control amount in a direction in which the range is away from the reference control amount, and the reference control amount. 2. The control device according to claim 1, wherein a target control amount that satisfies the constraint is selected from among target control amounts within the range based on a predicted value of a control amount that is a predetermined time ahead from a current time. ,
A value set based on the predicted value of the previous control amount for a time longer than the time constant relating to the change in the control amount, the predicted value of the previous control amount for the predetermined time, and the current control amount value A control device in which the range is defined by a value exceeding a current target control amount in a direction away from the reference control amount and the reference control amount. The control device according to claim 2,
The difference between the predicted value of the control amount ahead of the predetermined amount of time and the predicted value of the control amount ahead of the time constant and the current value relative to the predicted value of the control amount ahead of the time constant by a time longer than the time constant. A control device in which the range is defined by a value that exceeds a current target control amount in a direction away from the reference control amount by a value set based on a difference between control amount values of the control amount and the reference control amount .

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