JP2015010548A - Control device for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve both responsiveness and convergence properties of boost pressure in a control device for an engine.SOLUTION: A control device 1 for an engine for controlling a boost pressure by controlling an opening of a waste gate valve 17 includes setting means 2 for setting a virtual boost pressure Pcorresponding to an output request to the engine 10. The control device 1 further includes filter value calculating means 3 for calculating filter values P, Pin which filter processing that simulates transient response delay of the boost pressure is applied to the virtual boost pressure P. Moreover, the control device 1 includes: stationary time opening calculation means 4a for calculating a waste gate opening of the waste gate valve 17 for generating the virtual boost pressure Pas a stationary time opening R; and opening correction amount calculating means 4b for calculating a correction amount C of the waste gate opening relative to the stationary time opening R on the basis of a difference between the virtual boost pressure Pand the filter values P, P.

Description

  The present invention relates to an engine control device that controls supercharging pressure by adjusting the opening of a waste gate valve.

  Conventionally, in an engine equipped with a supercharging system that uses the exhaust pressure of the engine, a waste gate valve is provided in a bypass for bypassing the turbocharging turbine that is interposed on the exhaust passage, and depending on the supercharging state A technique for controlling the open / close state is known. That is, the pressure of the intake air flowing into the cylinder is controlled by adjusting the opening of the waste gate valve (waste gate opening) according to the supercharging pressure required for the engine. In general control of the waste gate valve, the rotation speed of the supercharging turbine is lowered and the supercharging pressure is lowered by increasing the waste gate opening degree (controlling in the opening direction). Conversely, when the waste gate opening is decreased (controlled in the closing direction), the rotational speed of the turbocharging turbine increases and the supercharging pressure increases.

  In such a supercharging system, a response delay occurs between the control of the waste gate valve and the actual change of the supercharging pressure. This delay in response includes, for example, a time lag until a change in the wastegate opening is reflected in a change in the exhaust amount flowing into the turbocharger turbine, or a time lag until the intake air supercharged by the compressor reaches the intake manifold. Is included. Therefore, even if the waste gate valve is controlled without delay so that the waste gate valve corresponds to the target supercharging pressure when the target supercharging pressure required for the engine increases rapidly, the actual supercharging pressure increases rapidly. It is difficult to let

  In order to solve the above problem, it has been proposed to control the waste gate opening based on the difference between the target boost pressure and the actual boost pressure. That is, the deviation of the actual control amount with respect to the target value is fed back and corrected in the next control cycle. By adopting such a control method, the correction amount increases and the supercharging response improves as the deviation of the supercharging pressure increases (see, for example, Patent Document 1).

JP 2006-274831 A

  However, in the control method based on the difference between the target supercharging pressure and the actual supercharging pressure, a steady deviation (offset) may occur between the target supercharging pressure and the actual supercharging pressure. There is a problem that it is difficult to improve. For example, when there is a steady deviation that stabilizes in a state where the actual supercharging pressure is slightly larger than the target supercharging pressure, the actual supercharging pressure becomes too high in response and the controllability is impaired.

  It is also conceivable to adopt a method of converging the supercharging pressure to the target supercharging pressure by adding a correction term for eliminating the above-described steady deviation. For example, it is conceivable to reflect the integrated value of the deviation of the actual control amount with respect to the target value in the correction amount. However, in this case, the responsiveness may be lowered instead of improving the convergence. In general, in the feedback control of the supercharging pressure, it is difficult to provide a correction amount that improves the convergence while improving the response, and it is difficult to improve the drivability.

  One of the purposes of this case was devised in view of the above-described problems. In an engine control device that controls the supercharging pressure by adjusting the opening of the waste gate valve, the responsiveness and convergence of the supercharging pressure are considered. To improve both. The present invention is not limited to this purpose, and is a function and effect derived from each configuration shown in the embodiments for carrying out the invention described later, and other effects of the present invention are to obtain a function and effect that cannot be obtained by conventional techniques. Can be positioned.

(1) The engine control device disclosed here is an engine control device that controls the supercharging pressure by adjusting the opening degree of the waste gate valve. The control apparatus simulates a transient response delay of the supercharging pressure with respect to the virtual supercharging pressure set by the setting means for setting the virtual supercharging pressure corresponding to the output request to the engine and the setting means Filter value calculation means for calculating a filter value subjected to the filter processing.
In addition, there is provided a steady-state opening degree calculation means for calculating a wastegate opening degree of the wastegate valve that generates the virtual supercharging pressure set by the setting means as a steady-state opening degree. Further, based on the difference between the virtual boost pressure set by the setting means and the filter value calculated by the filter value calculation means, a correction amount of the waste gate opening degree with respect to the steady-state opening degree is calculated. Opening correction amount calculating means is provided.

(2) First filter value calculation means for calculating, as the filter value, a first filter value that has been subjected to filter processing that simulates a transient response delay in the fully closed state of the waste gate valve. It is preferable to have. In this case, it is preferable that the opening correction amount calculating means calculates the correction amount based on a difference between the virtual supercharging pressure and the first filter value.
The “transient response delay in the fully closed state” referred to here is a transient response delay having the fastest response speed in the engine operating state at that time. Thereby, the increasing gradient of the first filter value is maximized in the operating state of the engine at that time.

  (3) It is preferable that the opening degree correction amount calculating means corrects the waste gate opening degree in a closing direction when a difference between the virtual supercharging pressure and the first filter value is a predetermined value or more. That is, it is preferable to correct the wastegate opening in the closing direction rather than the steady-state opening during the first half of the process (transitional state) in which the supercharging pressure varies (transitional first half). In addition, you may define the transition first term here as "the state where the difference of the said virtual supercharging pressure and said 1st filter value is more than a predetermined deviation."

(4) The filter value calculation means includes second filter value calculation means for calculating, as the filter value, a second filter value that has been subjected to filter processing that simulates a transient response delay in a fully open state of the waste gate valve. It is preferable. In this case, the opening correction amount calculating means calculates the correction amount based on the difference between the virtual supercharging pressure and the first filter value and the difference between the virtual supercharging pressure and the second filter value. It is preferable to calculate.
The “transient response delay in the fully opened state” here is a transient response delay having the slowest response speed in the engine operating state at that time. As a result, the increasing gradient of the second filter value is minimized in the engine operating state at that time.

  (5) The opening degree correction amount calculation means is configured such that a difference between the virtual supercharging pressure and the first filter value is less than a predetermined value, and a difference between the virtual supercharging pressure and the second filter value is It is preferable to correct the waste gate opening degree in the opening direction when the second predetermined value or more is reached. In other words, it is preferable to correct the waste gate opening in the opening direction rather than the steady-state opening in the second half of the process (transient state) in which the supercharging pressure varies (transient state). The late transition term here may be defined as “a state where the difference between the virtual supercharging pressure and the first filter value is less than a predetermined deviation” or “the virtual supercharging pressure and the second filter”. You may define as the state where the difference with a value is less than a 2nd predetermined deviation.

  (6) It is preferable that the filter value calculation means performs the filter process using a time constant (or filter coefficient) set based on an intake air amount and an engine rotation speed of the engine. For example, it is preferable that the first filter value calculation means calculates the first filter value according to the operating state of the engine. Or it is preferable that said 2nd filter value calculation means calculates said 2nd filter value according to the driving | running state of the said engine.

  (7) A positive correction amount for the opening correction amount calculating means to correct the waste gate opening in the opening direction from the steady-state opening according to the difference between the virtual supercharging pressure and the filter value; It is preferable to have a map that gives a negative correction amount that corrects the wastegate opening in the closing direction rather than the steady-state opening.

  According to the disclosed engine control device, by calculating the opening correction amount of the waste gate opening based on the difference between the virtual supercharging pressure and the filter value, the actual supercharging pressure can be calculated in calculating the opening correction amount. Since it is not used, it is possible to eliminate the influence of a steady deviation that may occur between the virtual boost pressure and the actual boost pressure. Therefore, the responsiveness and convergence of the supercharging pressure can be improved, and drivability can be improved.

It is a figure which illustrates the structure of the engine which concerns on one Embodiment. It is a figure which illustrates the hardware constitutions of an engine control apparatus. It is a figure which illustrates the block configuration of an engine control apparatus. It is a graph which shows the transient response delay of a supercharging pressure, (a) respond | corresponds to a 1st filter value, (b) respond | corresponds to a 2nd filter value. It is a graph which shows the change of a waste gate opening degree, (a) shows the change from a fully-closed state to a steady-state opening degree, (b) shows the change from a fully open state to a steady-state opening degree. It is a graph which illustrates a part of three-dimensional map which concerns on the setting of correction amount, (a) shows a relationship with a 1st pressure difference, (b) shows a relationship with a 2nd pressure difference. It is a flowchart which illustrates the control procedure in an engine control apparatus. It is a time chart for demonstrating the control effect | action by an engine control apparatus, (a) is an accelerator operation amount, (b) is a 1st filter value, (c) is a 2nd filter value, (d) is a waste gate opening degree. , (E) shows the actual supercharging pressure.

  An engine control apparatus as an embodiment will be described with reference to the drawings. Note that the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not explicitly described in the following embodiment. Each configuration of the present embodiment can be implemented with various modifications without departing from the spirit of the present embodiment, and can be selected or combined as necessary.

[1. Device configuration]
[1-1. engine]
The engine control device of the present embodiment is applied to the on-vehicle gasoline engine 10 (hereinafter simply referred to as the engine 10) shown in FIG. FIG. 1 shows one of a plurality of cylinders (cylinders) provided in a multi-cylinder engine 10. A piston is slidably mounted in the cylinder, and the reciprocating motion of the piston is converted into rotational motion of the crankshaft via a connecting rod (connecting rod).
An intake port and an exhaust port are provided on the top surface of each cylinder, and an intake valve and an exhaust valve are provided in each port opening. In addition, a spark plug 15 is provided between the intake port and the exhaust port in a state where the tip thereof protrudes toward the combustion chamber. The timing of ignition at the spark plug 15 (ignition timing) is controlled by the engine control device 1.

  The engine 10 is provided with an in-cylinder injection valve 11 and a port injection valve 12 as injectors for supplying fuel to each cylinder. The in-cylinder injection valve 11 is a direct injection injector that directly injects fuel into the cylinder, and the port injection valve 12 is an injector that injects fuel into the intake port. The fuel injection amount injected from these injection valves 11 and 12 and the injection timing thereof are controlled by the engine control device 1. For example, a control pulse signal is transmitted from the engine control device 1 to the injection valves 11 and 12, and the injection holes of the injection valves 11 and 12 are opened only during a period corresponding to the magnitude of the control pulse signal. Accordingly, the fuel injection amount becomes an amount corresponding to the magnitude (drive pulse width) of the control pulse signal, and the injection timing corresponds to the time when the control pulse signal is transmitted.

[1-2. Intake and exhaust system]
Upper portions of the intake valve and the exhaust valve are connected to a variable valve mechanism for changing a valve lift amount and a valve timing. The variable valve mechanism includes a variable valve lift mechanism and a variable valve timing mechanism as a mechanism for changing, for example, the rocking amount and rocking timing of the rocker arm. The operations of the intake valve and the exhaust valve are controlled by an engine control device 1 described later via these variable valve mechanisms.

  The intake system 20 and the exhaust system 30 of the engine 10 are provided with a turbocharger 16 (supercharger) that performs supercharging with exhaust pressure. The turbocharger 16 is interposed across both the intake passage 21 connected to the upstream side of the intake port and the exhaust passage 31 connected to the downstream side of the exhaust port. The turbine 16A (supercharging turbine) of the turbocharger 16 is rotated by the exhaust pressure in the exhaust passage 31 and transmits the rotational force to the compressor 16B on the intake passage 21 side. In response to this, the compressor 16B feeds the air in the intake passage 21 while compressing it to the downstream side, and supercharges each cylinder. The supercharging operation of the turbocharger 16 is controlled by the engine control device 1.

  An intercooler 25 is provided on the intake passage 21 downstream of the compressor 16B to cool the compressed intake air. Further, an air filter 22 is provided on the upstream side of the compressor 16B, and air taken in from the outside is filtered here. Further, a bypass passage 23 is provided so as to connect the upstream and downstream intake passages 21 of the compressor 16 </ b> B, and a bypass valve 24 is interposed on the bypass passage 23. The amount of air flowing through the bypass passage 23 is adjusted according to the opening degree of the bypass valve 24. The bypass valve 24 is controlled, for example, in the opening direction when the vehicle is suddenly decelerated, and functions to release the supercharging pressure supplied from the compressor 16B to the upstream side again. The opening degree of the bypass valve 24 is controlled by the engine control device 1.

  A throttle body is connected to the downstream side of the intercooler 25, and an intake manifold (intake manifold) is connected to the downstream side thereof. An electronically controlled throttle valve 26 is provided inside the throttle body. The amount of air flowing toward the intake manifold is adjusted according to the opening of the throttle valve 26 (throttle opening TH). The throttle opening TH is controlled by the engine control device 1.

  The intake manifold (intake manifold) is provided with a surge tank 27 for temporarily storing air flowing to each cylinder. The intake manifold downstream of the surge tank 27 is formed so as to branch toward the intake port of each cylinder, and the surge tank 27 is located at the branch point. The surge tank 27 functions to alleviate intake pulsation and intake interference that can occur in each cylinder.

  A catalyst device 33 is interposed on the exhaust passage 31 downstream of the turbine 16A. This catalyst device 33 purifies, decomposes, and removes components such as PM (Particulate Matter), nitrogen oxide (NOx), carbon monoxide (CO), and hydrocarbon (HC) contained in the exhaust gas, for example. It has a function to do. Further, an exhaust manifold (exhaust manifold) branched toward the exhaust port of each cylinder is connected to the upstream side of the turbine 16A.

  A bypass 32 is provided so as to connect the upstream and downstream exhaust passages 31 of the turbine 16 </ b> A, and an electronically controlled waste gate valve 17 is interposed on the bypass 32. The waste gate valve 17 is a supercharging pressure adjusting valve for controlling the exhaust flow rate flowing into the turbine 16A side to change the supercharging pressure. The waste gate valve 17 is provided with a waste gate actuator 18 to electrically control the position (that is, the opening) of the valve body. The opening degree of the waste gate valve 17 (the waste gate opening degree D) is controlled by the engine control device 1.

[1-3. Sensor system]
An air flow sensor 52 for detecting the intake flow rate Q _IN is provided in the intake passage 21. The intake air flow rate Q _IN is a parameter corresponding to the flow rate of air that has passed through the air filter 22. An intake manifold pressure sensor 53 and an intake air temperature sensor 54 are provided in the surge tank 27. Intake manifold pressure sensor 53 detects the pressure in the surge tank 27 as the intake manifold pressure P _IM, the intake air temperature sensor 54 for detecting an intake air temperature T _IM in the surge tank 27.

In the vicinity of the crankshaft, an engine speed sensor 55 that detects the engine speed Ne (the number of revolutions per unit time) is provided. A cooling water temperature sensor 56 for detecting the temperature of the engine cooling water (cooling water temperature W _T ) is provided at an arbitrary position on the cooling water circulation path of the engine 10.

The waste gate actuator 18 is provided with a hall sensor 57 that detects the stroke of the valve body driving member corresponding to the waste gate opening degree D. The stroke detected by the hall sensor 57 corresponds to the amount of movement of the valve body drive member from the reference position. Also, at any position within or vehicle engine control device 1, the atmospheric pressure sensor 58 is provided to detect the atmospheric pressure P _BP. Information atmospheric pressure P _BP is used, for example, when estimating the upstream pressure P _THU of the throttle valve 26.

  An accelerator opening sensor 59 for detecting the amount of depression of the accelerator pedal (accelerator opening APS) is provided at an arbitrary position of the vehicle. The accelerator opening APS is a parameter corresponding to the driver's acceleration request and intention to start, in other words, a parameter correlated to the load of the engine 10 (output request to the engine 10). Various information detected by the various sensors 52 to 59 is transmitted to the engine control apparatus 1.

[1-4. Control system]
A vehicle equipped with the engine 10 is provided with an engine control device 1 (Engine Electronic Control Unit). The engine control device 1 is configured as an electronic device in which a microprocessor such as a CPU (Central Processing Unit) and an MPU (Micro Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like are integrated. Is connected to a communication line of an in-vehicle network provided in the network. Note that various known electronic control devices such as a brake control device, a transmission control device, a vehicle stability control device, an air conditioning control device, and an electrical component control device are communicably connected to each other on the in-vehicle network. An electronic control device other than the engine control device 1 is called an external control system, and a device controlled by the external control system is called an external load device.

The engine control device 1 is an electronic control device that comprehensively controls a wide range of systems such as an ignition system, a fuel system, an intake / exhaust system, and a valve system related to the engine 10, and air supplied to each cylinder of the engine 10. It controls the amount, fuel injection amount, ignition timing of each cylinder, supercharging pressure, etc. The aforementioned various sensors 52 to 59 are connected to the input port of the engine control apparatus 1. Specific input information includes accelerator opening APS, intake air flow rate Q _IN , intake manifold pressure P _IM , intake air temperature T _IM , engine speed Ne, cooling water temperature W _T , stroke of waste gate actuator 18 (waste gate opening D ), Information such as atmospheric pressure P _BP .

  Specific control objects of the engine control device 1 include the fuel injection amount and the injection timing injected from the in-cylinder injection valve 11 and the port injection valve 12, the ignition timing by the ignition plug 15, and the valve lifts of the intake valve and the exhaust valve. Examples include the amount and valve timing, the operating state of the turbocharger 16, the throttle opening TH, the opening of the bypass valve 24, the waste gate opening D, and the like. In the present embodiment, control of the waste gate opening degree D when the accelerator pedal is depressed will be described in detail.

[2. Overview of control]
The waste gate opening degree D is basically controlled to be an opening degree corresponding to the output required for the engine 10. For example, a driver's acceleration request or a request from an external load device is input to the engine control device 1, and a target torque of the engine 10 is set according to these requests. Then, a target intake air amount corresponding to the target torque is calculated, a virtual boost pressure as a target value of the boost pressure is calculated, and a waste gate opening D is a target opening corresponding to the virtual boost pressure. It is controlled to become.

  On the other hand, since the actual supercharging pressure (actual supercharging pressure) fluctuates with respect to the change in the waste gate opening degree D, good response may not be obtained depending on the operating state of the engine 10. Even if the deviation of the actual control amount from the target value is fed back and corrected in the next control cycle, a steady deviation (offset) occurs between the virtual boost pressure and the actual boost pressure, and the boost pressure It may be difficult to improve convergence. Therefore, in this case, the responsiveness and convergence of the boost pressure are improved by giving the opening correction amount C based on the predicted response delay value without feeding back the deviation of the actual control amount from the target value to the correction amount. To do.

  The opening correction amount C is set based on the difference between the filter value simulating the transient response delay and the virtual boost pressure. The transient response delay is simulated using models such as a primary response delay element, a secondary response delay element, and dead time. Therefore, the magnitude of the difference between the virtual boost pressure (target opening) and the actual boost pressure (actual waste gate opening D) is not reflected in the opening correction amount C as in the conventional feedback control.

  There are two possible methods for setting the opening correction amount C. The first method predicts the transient response delay of the actual supercharging pressure in the operating state of the engine 10 at that time, and the opening degree based on the difference between the filter value obtained by simulating this and the virtual supercharging pressure. A correction amount C is set. The second method predicts the fastest transient response delay and the slowest transient response delay that can be assumed in the operating state of the engine 10 at that time, and simulates these two filter values and a virtual transient delay. The opening correction amount C is set based on the respective differences from the supply pressure.

  The first method corresponds to a method using a predicted value (filter value) simulating a transient response delay instead of the actual boost pressure in the conventional feedback control. However, unlike the conventional feedback control, the predicted value does not have to exhibit a behavior that closely mimics the fluctuation of the actual boost pressure. For example, the predicted value may be changed slightly later than the actual supercharging pressure, or may be changed slightly faster than the actual supercharging pressure. That is, the “degree of transient response delay” reflected in the predicted value can be arbitrarily set as long as it corresponds to the operating state of the engine 10.

  The second method corresponds to a method using two types of predicted values having different “degrees of transient response delay” instead of the actual boost pressure in the conventional feedback control. By using two predicted values, it becomes possible to set an appropriate opening correction amount C according to the change rate of each predicted value, and controllability is improved. For example, the transitional state until the actual boost pressure converges to the virtual boost pressure is classified into the first half of the transition (first half) and the second half of the transition (second half). It is conceivable to associate two predicted values. In this case, the filter value obtained by simulating the fastest transient response delay is mainly used for setting the opening correction amount C in the first half of the transition. Further, the filter value obtained by simulating the slowest transient response delay is mainly used for setting the opening correction amount C in the late transition period.

  The “fastest transient response delay” related to the calculation of the filter value is a transient response delay when the waste gate opening degree D is fully closed. On the contrary, the “latest transient response delay” is a transient response delay when the waste gate opening D is fully opened. This is because the time until the change in the exhaust amount appears as the change in the supercharging pressure is shorter as the waste gate opening D is smaller, and the time is longer as the waste gate opening D is larger.

[3. Configuration of control device]
A hardware configuration of the engine control apparatus 1 is illustrated in FIG. The engine control device 1 includes a central processing unit 71, a main storage device 72, an auxiliary storage device 73, and an interface device 74, and these are communicably connected via an internal bus 75. In addition, each of these devices 71 to 74 operates by receiving power supply from a power source (not shown) such as an in-vehicle battery or a button battery.

  The central processing unit 71 is a processing unit (processor) incorporating a control unit (control circuit), an arithmetic unit (arithmetic circuit), a cache memory (register group), and the like. Further, the main storage device 72 is a memory device that stores programs and working data, and includes, for example, the aforementioned RAM and ROM. On the other hand, the auxiliary storage device 73 is a memory device that stores data and programs that are held for a longer period of time than the main storage device 72. This includes storage devices such as solid state drives (SSD). The interface device 74 controls input / output (I / O) between the engine control device 1 and the outside. For example, information is exchanged between the various sensors 52 to 59 mounted on the vehicle and the external control system and the engine control device 1 through the interface device 74.

  FIG. 3 is a block diagram for explaining the processing content executed by the engine control apparatus 1. These processing contents are recorded on the auxiliary storage device 73 or a removable medium as an application program, for example. Further, when the program is executed, the contents of the program are expanded in the memory space in the main storage device 72 and executed by the central processing unit 71. When the processing contents are classified functionally, this program is provided with a setting unit 2, a filter value calculation unit 3, a waste gate control unit 4, and a throttle control unit 5. Each of these elements may be realized by an electronic circuit (hardware), or a part of these functions may be provided as hardware and the other part may be software.

[3-1. Setting section]
Setting unit 2 (setting means) is for setting a virtual boost pressure P _A in accordance with the output of the engine 10 as a target. Virtual supercharging pressure P _A is the boost pressure required to achieve the engine output to the target. The setting unit 2 includes a required torque setting unit 2a and a virtual supercharging pressure setting unit 2b.

  The required torque setting unit 2a sets the torque required for the engine 10 as the required torque Pi (output request). Here, the required torque Pi is set based on the driver's acceleration request. The required torque Pi is set based on a map, a mathematical expression, or a function using the engine speed Ne and the accelerator opening APS as arguments. For example, the required torque Pi is set larger as the engine speed Ne is higher or the accelerator opening APS is larger. The required torque Pi may be set in consideration of not only the driver's acceleration request but also a request from the external load device.

Virtual supercharging pressure setting unit 2b is for setting a virtual boost pressure P _A that corresponds to the required torque Pi set by required torque setting unit 2a. Virtual supercharging pressure P _A is (a target value of the supercharging pressure at the time, instantaneous value) supercharging pressure steady for realizing the driver's acceleration demand is equivalent to the request and the engine rotational speed Ne It is set based on a map, a mathematical expression, or a function with the torque Pi as an argument. For example, high engine rotational speed Ne, or as the demanded torque Pi is large, virtual boost pressure P _A is set larger. Value of the virtual boost pressure P _A that is set here is transmitted to the filter value calculation section 3.

In order to actually realize the driver's acceleration request, it is preferable to control the amount of air introduced into the cylinder of the engine 10 and to control not only the supercharging pressure but also the throttle opening TH. preferable. Further, the supercharging pressure for satisfying the required torque Pi changes according to the throttle opening TH. This means that the virtual boost pressure P _A may not be associated necessarily one-to-one to an engine output. Therefore, according to the operating state of the engine 10, another factor is the engine output be set virtual boost pressure P _A in consideration of the (fuel, pumping loss, exhaust performance, state of the variable valve mechanism) Good. For example, it is possible to set a virtual boost pressure P _A regardless of the required torque Pi.

[3-2. Filter value calculation unit]
Filter value calculating unit 3 (the filter value calculating means) is for carrying out the filtering process which simulates the transient response delay of the actual supercharging pressure to the virtual supercharging pressure P _A. Here, of the two types of setting methods related to the opening correction amount C described above, a method for calculating the filter value used in the second method will be described. The filter value calculation unit 3 includes a first filter value calculation unit 3a (first filter value calculation unit) and a second filter value calculation unit 3b (second filter value calculation unit).

The first filter value calculation unit 3a calculates a first filter value P _B by performing a filter process that simulates a transient response delay in the fully closed state of the waste gate valve 17. This filtering process is performed to obtain the fastest transient response delay in the operating state of the engine 10 at that time (that is, the transient response delay when the waste gate opening D is fully closed in the operating state of the engine 10 at that time). Simulated.

The "fastest transient response delay", as shown in FIG. 4 (a), when the virtual boost pressure P _A is increased accelerator pedal is depressed, for example, time t _0, the waste gate valve 17 This means a transient response delay in which the boost pressure increases with almost the same increase gradient as when the is controlled to the fully closed state. That is, the first filter value P _B is given a characteristic that increases with substantially the same increasing gradient as when the waste gate valve 17 is controlled to be in the fully closed state. Incidentally, in FIG. 4 (a), the value of virtual boost pressure P _A at time t ₀ after showed the case is constant, the actual virtual supercharging pressure P _A may vary with time.

In the present embodiment, as shown in FIG. 5 (a), from the time t ₀ after maintaining the fully closed state of the waste gate valve 17 a predetermined time, as the boost pressure does not exceed greatly the virtual boost pressure P _A , opening degree corresponding wastegate opening D virtual boost pressure P _a (i.e., opening degree R steady state to be described later) the behavior of the supercharging pressure in case of increasing to the behavior of the first filter value P _B Set as

FIG. 5 (a) as indicated by a one-dot chain line in, and hold maintaining the waste gate valve 17 is fully closed, beyond the boost pressure virtual supercharging pressure P _A, in FIGS. 4 (a) Converges to the fully closed supercharging pressure P _HEI (P _A <P _HEI ) indicated by a one-dot chain line. On the other hand, the increase gradient when the boost pressure rises toward the fully closed boost pressure P _HEI is a gradient according to the operating state of the engine 10 at that time (engine rotational speed Ne, intake air amount, etc.). . Therefore, the increasing gradient of the first filter value P _B indicated by the solid line in FIG. 4A can be estimated from the operating state of the engine 10 at that time.

In the first filter value calculating section 3a, which were subjected to such a filtering process on the virtual boost pressure P _A is calculated as a first filter value P _B. The first filter value P _B is in a transient state until the supercharging pressure is converged to the virtual boost pressure P _A, the parameter for grasping the most rapid transients.

The first filter value calculating section 3a, as shown in Equation 1 below, assuming that the first filter value P _B is represented by the transfer function of the secondary delay with respect to the virtual supercharging pressure P _A, the first filter The value P _B is calculated. The subscript n in these mathematical expressions represents the calculation cycle. For example, P _{B (n)} is the first filter value P _B obtained in the current computation cycle, and P _{B (n-1)} is the first filter value P _B obtained in the previous computation cycle (that is, the previous value). ). The coefficient K ₁ is a first filter coefficient (corresponding to a time constant) corresponding to the reciprocal of the increasing gradient of the solid line in FIG. 4A, and is set according to the operating state of the engine 10. For example, the first filter coefficient K ₁ is set using a map, a mathematical expression, or a function using the engine speed Ne and the charging efficiency Ec (that is, the intake air amount) as arguments. Charging efficiency Ec is calculated based on the intake air flow rate Q _IN detected by the air flow sensor 52.

The filling efficiency Ec is obtained by normalizing the volume of air filled in the cylinder per unit combustion cycle (unit time) to the gas volume in the standard state and then dividing by the cylinder volume. In other words, the charging efficiency Ec represents the ratio of the mass of air filled in the cylinder to the mass of air occupying the cylinder under standard atmospheric conditions, and the air introduced into the cylinder per unit combustion cycle (unit time). It is a parameter corresponding to the quantity. Therefore, parameters correlating to the intake air amount such as the volume efficiency Ev, the intake flow rate Q _IN , the target torque, and the target engine output may be used instead of the charging efficiency Ec.

Second filter value calculating unit 3b is subjected to a filtering process which simulates the transient response delay in the fully opened state of the waste gate valve 17, and calculates the second filter value P _C. This filtering process simulates the slowest transient response delay in the operating state of the engine 10 at that time (that is, the transient response delay when the waste gate opening D is fully opened in the operating state of the engine 10 at that time). It is assumed that.

The "slowest transient response delay", as shown in FIG. 4 (b), for example, at time t ₀ virtual boost pressure P _A is in increased, to control the waste gate valve 17 fully open It means a transient response delay in which the supercharging pressure increases with almost the same increase gradient as the case. That is, the second filter value P _C, properties such as increased at approximately the same incremental gradient and when controlling the waste gate valve 17 fully open is given. This increasing gradient is smaller and gentler than the increasing gradient when the waste gate valve 17 is controlled to the fully closed state.

In the present embodiment, as shown in FIG. 5 (b), from the time t ₀ after maintaining the open state of the waste gate valve 17 a predetermined time, as the boost pressure does not converge remains below the virtual boost pressure P _A , opening degree corresponding wastegate opening D virtual boost pressure P _a (i.e., opening degree R steady state to be described later) is the behavior of the supercharging pressure in the case of reduced to the behavior of the second filter value P _C Set as

5B, if the waste gate valve 17 is kept in the fully open state as indicated by the one-dot chain line in FIG. 5B, the fully open supercharging pressure P _KAI (P It converges to _KAI <P _A ). On the other hand, the increasing gradient when the supercharging pressure increases toward the fully open supercharging pressure P _KAI is a gradient according to the operating state of the engine 10 at that time (engine rotational speed Ne, intake air amount, etc.). Thus, an increase gradient of the second filter value P _C indicated by a solid line in FIG. 4 (b), can be estimated from the operation state of the engine 10 at that time.

In the second filter value calculating unit 3b, that has been subjected to such a filtering process on the virtual boost pressure P _A is calculated as the second filter value P _C. Second filter value P _C is in a transient state until the supercharging pressure is converged to the virtual boost pressure P _A, the parameter for grasping the most stable transients were.

Second filter value calculating unit 3b, as shown in equation 3 and 4 below, as the second filter value P _C is represented by the transfer function of the secondary delay with respect to the virtual supercharging pressure P _A, the second filter to calculate the value P _C. The coefficient K ₂ is a second filter coefficient (corresponding to a time constant) corresponding to the reciprocal of the increasing gradient of the solid line in FIG. 4B, and is set according to the operating state of the engine 10. For example, the second filter coefficient K ₂ is set using a map, a mathematical expression, or a function with the engine speed Ne and the charging efficiency Ec as arguments. Incidentally, when the operation state of the engine 10 are the same, the second filter coefficient value of K ₂ greater than the first value of the filter coefficient K ₁ (i.e., a K ₁ <K _2).

The value of the first filtered value P _B and the second filter value P _C calculated by the filter value calculating unit 3 is transmitted to the wastegate control unit 4.

[3-3. Wastegate control unit]
Wastegate control unit 4, the virtual boost pressure P _A, the first filter value P _B, and controls the wastegate opening D on the basis of the second filter value P _C. The waste gate control unit 4 includes a steady-state opening calculation unit 4a, an opening correction amount calculation unit 4b, and a control signal output unit 4c.

Steady opening calculation section 4a (steady opening calculation means) is for calculating the wastegate opening D to produce a virtual boost pressure P _A as steady opening R. The steady state opening R, means a waste gate opening D which supercharging pressure converges to a virtual boost pressure P _A in the case of continuing to maintain its opening. The steady-state opening degree calculation unit 4a calculates the steady-state opening degree R using a map, a mathematical formula, or a function using the engine speed Ne and the required torque Pi as arguments. The opening degree correction amount C calculated by the opening degree correction amount calculation unit 4b is an increase / decrease amount of the waste gate opening degree D (relative to the steady state opening degree R) based on the steady state opening degree R calculated here. Is defined as

Opening correction amount calculation section 4b (opening correction amount calculating means), based on the respective differences between the virtual boost pressure P _A and two filter value, calculates the opening correction amount C with respect to the steady opening R Is. Here, along with the difference between the virtual boost pressure P _A and the first filter value P _B is calculated as a first pressure difference DP _1, the difference between the virtual boost pressure P _A and the second filter value P _C is the It is calculated as a two-pressure difference DP _2. Further, the opening correction amount C is calculated based on the first pressure difference DP ₁ and the second pressure difference DP ₂ . The opening correction amount C calculated here is transmitted to the control signal output unit 4c.

Various methods for calculating the opening correction amount C can be considered. For example, it is conceivable to obtain the opening correction amount C using a map, a mathematical formula, or a function using the first pressure difference DP ₁ and the second pressure difference DP ₂ as arguments. In this case, it is sufficient to prepare opening correction amount C, and the relationship of the first pressure difference DP ₁ and the second pressure difference DP ₂ as a three-dimensional map. Part of the three-dimensional map is illustrated in FIGS. 6 (a) and 6 (b).

FIG. 6A shows the relationship between the opening degree correction amount C and the first pressure difference DP ₁ when the second pressure difference DP ₂ is constant. First pressure difference DP _1, a value becomes maximum at the time t ₀ of the virtual boost pressure P _A is increased as shown in FIG. 4 (a), as compared to the second pressure difference DP _2, decreases faster slightly It is. In other words, the process of the first pressure difference DP ₁ is reduced corresponds to the process of the supercharging pressure is converged toward the virtual boost pressure P _A half-life in (transient state) (transient year). Therefore, by setting the opening correction amount C according to the first pressure difference DP _1, the rise of the supercharging pressure is improved.

The characteristic indicated by the solid line in FIG. 6A is that the opening correction amount C is 0 when the first pressure difference DP ₁ is less than the predetermined value A ₁ , and the first pressure difference DP ₁ is equal to or greater than the predetermined value A _1. In this case, the opening correction amount C is set to a negative value. The negative opening correction amount C is a correction amount for correcting the waste gate opening D in the closing direction rather than the steady-state opening R. The predetermined value A ₁ in FIG. 6A varies depending on the second pressure difference DP ₂ . Further, as indicated by a broken line in the drawing, the opening correction amount C may be partially set to a positive value within a range where the first pressure difference DP ₁ is equal to or less than a predetermined value A ₁ .

FIG. 6B shows the relationship between the opening correction amount C and the second pressure difference DP ₂ when the first pressure difference DP ₁ is constant. Second pressure difference DP ₂ is different from the first pressure difference DP _1, a value that decreases a little later. In other words, the process of the second pressure difference DP ₂ is decreased, corresponds to the process of the supercharging pressure is converged toward the virtual boost pressure P _A period late in (transient state) (transient late). Therefore, by setting the opening correction amount C according to the second pressure difference DP _2, overshoot or convergence of the supercharging pressure is improved.

The characteristic shown in FIG. 6B is that when the second pressure difference DP ₂ is less than the second predetermined value A ₂ , the opening degree correction amount C is 0, and the second pressure difference DP ₂ is the second predetermined value A _2. As described above, the opening correction amount C is set to a positive value when it is less than the third predetermined value A ₃ (however, A ₂ <A ₃ ). The positive opening correction amount C is a correction amount for correcting the waste gate opening D in the opening direction from the steady-state opening R. The second predetermined value A ₂ and the third predetermined value A ₃ in FIG. 6B vary according to the first pressure difference DP ₁ . As indicated by broken lines in FIG. 6 (b), the by the first pressure difference DP ₁ value map area negative opening correction amount C is set may also be present.

6A and 6B are graphs for explaining a three-dimensional map in which the relationship between the opening correction amount C, the first pressure difference DP ₁ and the second pressure difference DP ₂ is defined. It is also conceivable that two types of opening correction amounts are calculated using, and the final opening correction amount C is obtained based on these. That is, from the relationship shown in FIG. 6 (a), to calculate the first opening correction amount C ₁ corresponding to the first pressure difference DP _1, from the relationship shown in FIG. 6 (b), the second The second opening correction amount C ₂ corresponding to the pressure difference DP ₂ may be calculated. Further, the final opening correction amount C may be obtained as the sum of the first opening correction amount C ₁ and the second opening correction amount C ₂ , or may be obtained as a product of these.

  The control signal output unit 4c sets an addition value of the steady-state opening degree R and the opening degree correction amount C as a target opening degree of the waste gate valve 17, and outputs a control signal corresponding thereto to the waste gate actuator 18. It is. The waste gate actuator 18 drives the valve body driving member with a stroke corresponding to the control signal. As a result, the actual waste gate opening D becomes the target opening corresponding to the addition value of the steady-state opening R and the opening correction amount C.

When the opening correction amount C calculated by the opening correction amount calculation unit 4b is negative, the actual wastegate opening D is controlled in the closing direction rather than the normal opening R, and the opening correction amount C is positive. In this case, the actual waste gate opening degree D is controlled in the opening direction rather than the steady-state opening degree R. For example, in the first half of the transition, the first pressure difference DP ₁ has not yet decreased, and the opening correction amount C is set to a negative value from the map characteristics as shown in FIG. The degree D is controlled more in the closing direction than the steady-state opening degree R. Thereby, the increase gradient of the supercharging pressure in the first half of the transition increases.

Further, the first pressure difference DP ₁ decreases and becomes close to 0 already in the latter half of the transition, while the second pressure difference DP ₂ decreases more slowly than the first pressure difference DP ₁ . At this time, since the opening correction amount C is temporarily set to a positive value from the map characteristics as shown in FIG. 6B, the waste gate opening D is more open than the steady-state opening R. Be controlled. Thereby, the overshoot of the supercharging pressure in the late transition period is suppressed, and the convergence is improved.

[3-4. Throttle control unit]
The throttle control unit 5 (throttle control means) controls the throttle opening TH based on the operating state of the engine 10. As shown in FIG. 3, the throttle control unit 5 includes a target flow rate calculation unit 5a, a pressure ratio calculation unit 5b, a flow velocity calculation unit 5c, a mass flow velocity calculation unit 5d, and a throttle area calculation unit 5e.

The target flow rate calculation unit 5a calculates the target flow rate Q as a target value of the intake air amount that passes through the throttle valve 26 per unit time based on the target torque of the engine 10. The target torque is calculated based on the aforementioned required torque Pi set from the engine rotational speed Ne and the accelerator opening APS, the external required torque requested from the external control system to the engine 10, and the like. Further, the target flow rate Q is calculated based on the target torque and the engine rotational speed Ne. At this time, the value of the target flow rate Q may be corrected based on the intake air temperature _TIM , the cooling water temperature W _T , the intake manifold pressure P _IM , the atmospheric pressure P _BP , the intake air density, and the like.

The pressure ratio calculation unit 5b calculates the pressure ratio between the upstream side and the downstream side of the throttle valve 26. The pressure ratio is a ratio (P _IM / P _THU ) between the intake manifold pressure P _IM actually detected by the intake manifold pressure sensor 53 and the upstream pressure P _THU of the throttle valve 26. Upstream pressure P _THU of the throttle valve 26 is calculated on the basis of the actual boost pressure and the atmospheric pressure P _BP. Moreover, the actual boost pressure, the virtual boost pressure P _A, the first filter value P _B, is calculated on the basis of the second filter value P _C and the like. Alternatively, the actual boost pressure may be estimated by calculating the pressure increase amount P _X due to supercharging from the waste gate opening D.

The flow velocity calculator 5c calculates the flow velocity of the intake air through the throttle based on the pressure ratio calculated by the pressure ratio calculator 5b. The flow velocity calculation unit 5c calculates a flow velocity U corresponding to the pressure ratio using a map, a mathematical expression, or a function in which the relationship between the pressure ratio and the amount of change in the flow rate through the throttle is defined. The flow velocity U increases as the pressure ratio (P _IM / P _THU ) decreases.

The mass flow velocity calculation unit 5d calculates a mass flow velocity M _MACH per unit area for the intake air passing through the throttle valve 26. The mass flow rate M _MACH is calculated based on the intake air temperature _TIM , the cooling water temperature W _T , the outside air temperature, the intake manifold pressure P _IM , the atmospheric pressure P _BP , the intake air density, and the like.
The throttle area calculator 5e calculates a target throttle opening area S corresponding to the throttle opening TH based on the target flow rate Q, the flow velocity U, and the mass flow velocity M _MACH . The target throttle opening area S is obtained by dividing the target flow rate Q _{TH_TGT} by the value obtained by multiplying the flow velocity U by the mass flow velocity M _MACH . Further, the throttle control unit 5 outputs a control signal for matching the opening area of the throttle valve 26 with the target throttle opening area S, thereby controlling the throttle opening TH.

[4. flowchart]
FIG. 7 is a flowchart illustrating the control procedure of the waste gate opening degree D. This flow is repeatedly performed in the engine control apparatus 1 at a predetermined calculation cycle.

In step A <b> 10, various information detected by the various sensors 52 to 59 is input to the engine control device 1. Here, accelerator opening APS, intake air flow rate Q _IN , intake manifold pressure P _IM , intake air temperature T _IM , engine speed Ne, cooling water temperature W _T , stroke of waste gate actuator 18 (waste gate opening D), atmospheric pressure P Information about _BP etc. is input. In step A20, the required torque Pi of the engine 10 is set in the required torque setting unit 2a of the setting unit 2 based on the engine speed Ne and the accelerator opening APS. Subsequently, at step A30, the virtual supercharging pressure setting unit 2b, on the basis of the engine rotational speed Ne and the required torque Pi, virtual boost pressure P _A is set. Here virtual boost pressure P _A is set, the corresponding instantaneous value of the desired boost pressure.

In step A40, the first filter value calculating section 3a, based on the engine rotational speed Ne and the charging efficiency Ec, the first filter coefficient K ₁ is calculated. Similarly, the second filter value calculating unit 3b, based on the engine rotational speed Ne and the charging efficiency Ec, the second filter coefficient K ₂ is calculated.
In step A50, the first filter value calculating section 3a, on the basis of the virtual boost pressure P _A and the first filter coefficient K _1, the first filter value P _B is calculated. The first filter value P _B is a calculated value of the boost pressure obtained by simulating the fastest transient response delay in the operating state of the engine 10 at that time. On the other hand, in step A60, the second filter value calculating unit 3b, on the basis of the virtual boost pressure P _A and the second filter coefficient K _2, the second filter value P _C is calculated. Second filter value P _C is the calculated value of the supercharging pressure obtained by simulating the slowest transient response delay in the operating state of the engine 10 at that time. These first filter value P _B, the second filter value P _C is the degree of the transient response delay, which is reflected in each is different.

In Step A70, the steady-state opening degree calculation unit 4a calculates the steady-state opening degree R based on the engine speed Ne and the required torque Pi. In step A80, the opening correction amount calculation unit 4b, the virtual with boost pressure P first pressure difference from _A to the first filter value P _B is subtracted DP ₁ is calculated, the virtual boost pressure P _A second filter value P _C is the second pressure difference DP ₂ is subtracted is calculated from. In step A90, the opening correction amount C is calculated based on the first pressure difference DP ₁ and the second pressure difference DP ₂ . The opening correction amount C is given by the sum or product of the first opening correction amount C ₁ and the second opening correction amount C ₂ corresponding to the first pressure difference DP ₁ and the second pressure difference DP ₂ , respectively. Alternatively, the first pressure difference DP ₁ and the second pressure difference DP ₂ may be given as arguments based on a map as shown in FIGS. 6 (a) and 6 (b).

  In step A100, the control signal output unit 4c calculates the addition value of the steady-state opening R and the opening correction amount C as a target value for the waste gate opening D, and outputs a control signal to the waste gate actuator 18. The waste gate actuator 18 drives the valve body driving member with a stroke corresponding to the control signal, and the waste gate opening D becomes an opening corresponding to the addition value of the steady-state opening R and the opening correction amount C.

[5. Action]
As shown in FIG. 8 (a), when the accelerator pedal at time t ₀ is depressed, the required torque Pi is set based on the engine rotational speed Ne and the accelerator opening APS at that time. Further, FIG. 8 (d), the (e), the steady state along with the boost pressure P _A is set virtual based on the engine rotational speed Ne and the required torque Pi, corresponding to the virtual boost pressure P _A The opening degree R is calculated.

In the filter value calculating unit 3, a first filter value P _B simulating the fastest transient response delay with respect to the virtual supercharging pressure P _A, and the second filter value P _C simulating the slowest transient response delay is calculated. As shown in FIG. 8B, the first filter value P _B has substantially the same increase gradient as when the waste gate valve 17 is controlled to the fully closed state, and from the supercharging pressure at that time to the virtual supercharging pressure. quickly change toward the P _a. Here, placing the time on which the first filter value P _B substantially matches the virtual boost pressure P _A and t _1, the virtual boost pressure P _A and the period difference is not zero the first filter value P _B is From time t ₀ to time t ₁ . That is, the opening correction amount C is set by the first pressure difference DP ₁ during the period from time t ₀ to time t ₁ .

In contrast, the second filter value P _C, as shown in FIG. 8 (c), at approximately the same incremental gradient and when controlling the waste gate valve 17 fully open, the supercharging pressure at that time slowly it varies toward the virtual supercharging pressure P _a. Here, if put a time where the second filter value P _C substantially coincides with the virtual boost pressure P _A and t _2, the opening correction amount C by the second pressure difference DP ₂ is set, the time t ₀ a period of from up to time t _2.

Thus, between the time t ₀ ~t ₁ corresponding to the transient year, the first filter value P _B, the degree of each of the transient response delay of the second filter value P _C is reflected in the opening correction amount C. At this time, the second filter value P _C to reduce slowly, it is possible to reflect only the degree of the transient response delay of the first filter value P _B with the opening degree correction amount C. Meanwhile, between the time t ₁ ~t ₂ corresponding to the transient late, the first filter value P _B has a value close to the virtual supercharging pressure P _A, and has a first pressure difference DP ₁ almost 0 Therefore, it is possible to reflect only the degree of the transient response delay of the second filter value P _C in opening correction amount C.

Here, when the map of the opening correction amount C as shown in FIGS. 6A and 6B is given, the opening correction amount C in the first half of the transition is negative according to the first pressure difference DP _1. Is set to the value of Accordingly, as shown in FIG. 8D, the waste gate opening D in the first half of the transition is corrected in the closing direction rather than the steady-state opening R. Therefore, as shown in FIG. 8 (e), the actual boost pressure increases with an increasing gradient corresponding to the fastest transient response delay in the operating state of the engine 10 at that time, and the acceleration response is improved.

Further, the opening correction amount C in the transient later is set to a positive value in response to the second pressure difference DP _2. As a result, the waste gate opening D in the late transition period is corrected in the opening direction from the steady-state opening R, as shown in FIG. Therefore, the actual overshoot supercharging pressure exceeds the virtual boost pressure P _A is suppressed, the convergence of the supercharging pressure is improved.

[6. effect]
(1) In the above-described engine control device 1, since the actual supercharging pressure to the calculation of the opening correction amount C is not used, the effect of steady state error that may occur between the virtual boost pressure P _A and the actual boost pressure Can be eliminated. Therefore, the responsiveness, convergence and stability of the supercharging pressure can be improved, and drivability can be improved.

The virtual boost pressure P _A and the filter value P _B, by calculating an opening degree correction amount C of the waste gate opening D on the basis of the difference between P _C, to give an appropriate degree of opening correction amount C can, while rapidly brought close to the actual boost pressure the virtual supercharging pressure P _a, it is possible to shorten the convergence time of the actual supercharging pressure. In particular, the filter value P _B, P _C, the actual transient response delay of the supercharging pressure from being a value obtained through simulating the filtering, the opening correction amount C that transient response delay of the supercharging pressure is considered The opening correction amount C suitable for the operating state of the engine 10 can be given.

(2) In the engine control apparatus 1 described above, the first filter value is simulated by simulating a transient response delay in which the supercharging pressure increases with substantially the same increase gradient as when the waste gate valve 17 is controlled to be fully closed. P _B is calculated. By calculating the opening correction amount C based on the first pressure difference DP ₁ is the difference between the first filter value P _B and the virtual supercharge pressure P _A, the increase rate of the supercharging pressure the fastest state It is possible to make it closer, and it is possible to correct the delay in the rise of the actual boost pressure. That is, it is possible to improve the responsiveness in the first half of the transition in a transient state (a process in which the boost pressure varies).

(3) with respect to the first pressure difference DP _1, for example, as shown in FIG. 6 (a), so that the first pressure difference DP ₁ is opening correction amount C is a negative value when the predetermined value A ₁ or more In addition, the relationship between the first pressure difference DP ₁ and the opening correction amount C is determined. That is, the wastegate opening degree D is corrected in the closing direction at the initial stage even during the first half of the transition. By such control, it is possible to reduce the delay in the rise of the actual supercharging pressure and further improve the responsiveness.
Further, when the first pressure difference DP ₁ is smaller than the predetermined value A ₁ is opening correction amount C is set to 0 or a positive value. As a result, the wastegate opening degree D is controlled to the steady-state opening degree R at the end stage even in the first half of the transition, or is corrected slightly in the opening direction. Therefore, the convergence rate can be improved by slightly suppressing the increase rate of the actual supercharging pressure.

(4) In the engine control apparatus 1 described above, the second filter value P is simulated by simulating a transient response delay in which the supercharging pressure increases at substantially the same increasing gradient as when the waste gate valve 17 is controlled to be fully open. _C is calculated. Speaking on the basis of the second pressure difference DP ₂ is the difference between the second filter value P _C and the virtual boost pressure P _A (more precisely, based on the first pressure difference DP ₁ and the second pressure difference DP ₂ Te) by calculating an opening degree correction amount C, can be actual boost pressure is suppressed pressure changes from approaching the virtual supercharging pressure P _a. That is, it is possible to improve the convergence of the late transition in the transient state.

(5) with respect to the second pressure difference DP _2, for example, as shown in FIG. 6 (b), opening correction amount C is a positive value when the second predetermined value A ₂ or more and a third less than the predetermined value A ₃ Thus, the relationship between the second pressure difference DP ₂ and the opening correction amount C is determined. At this time, the difference between the first filter value P _B and the virtual boost pressure P _A is sufficiently small, and the first pressure difference DP ₁ is less than the predetermined value A ₁ , that is, from the beginning of the late phase to the middle stage. At the stage, the waste gate opening D is corrected in the opening direction. By such control, it is possible to suppress the overshoot by weakening the increase of the supercharging pressure, and to improve the convergence and stability of the actual supercharging pressure.

When the waste gate opening degree D is corrected in the opening direction from the early stage of the transition period, the third predetermined value A ₃ shown in FIG. 6B is moved to the right side on the graph, and the second pressure difference DP ₂ The relationship between the second pressure difference DP ₂ and the opening correction amount C may be set so that the opening correction amount C becomes a positive value when is greater than or equal to the second predetermined value A ₂ . Even with such a setting, it is possible to suppress the overshoot in the latter half of the transition and improve the convergence and stability of the actual boost pressure.

(6) In the engine control apparatus 1 described above, the first filter coefficient K ₁ and the second filter coefficient K ₂ are set based on the charging efficiency Ec corresponding to the intake air amount of the engine 10 and the engine rotational speed Ne. . These filter coefficients K _1, K ₂ is a parameter that corresponds to a time constant of filtering process for obtaining a first filtered value P _B and the second filter value P _C from the virtual boost pressure P _A. As described above, by setting the parameter corresponding to the time constant of the transient response delay according to the operating state of the engine 10, the convergence time of the boost pressure fluctuation simulated by the filter process can be optimized.

For example, the transient response delay time of the supercharging pressure changes depending on the exhaust flow rate (intake air amount) per unit time, so that the transient response delay time is constant even if the engine speed Ne is constant. Not exclusively. That is, FIG. 8 (b), the increase gradient of the boost pressure as shown by a dashed line in (c), the pressure change amount until the waste gate opening D and virtual boost pressure P _A (eg, the first pressure difference Not only DP ₁ and second pressure difference DP ₂ ) but also the operating state of the engine 10 changes.

By performing a simulation operation using a time constant set based on the operating state of the engine 10 for such a change in the transient response delay time, the first filter value P _B and the second filter with higher accuracy can be obtained. it is possible to calculate the value P _C. Accordingly, it is possible to improve the calculation accuracy of the opening correction amount C for controlling the behavior of the actual supercharging pressure, and it is possible to improve both the responsiveness and convergence of the actual supercharging pressure in the transient state.

(7) In the engine control apparatus 1 described above, as shown in FIG. 8D, when the waste gate opening D is corrected in the closing direction rather than the steady-state opening R in the transient state of the actual boost pressure. And a time to be corrected in the opening direction from the steady-state opening degree R. In this way, by using a control map that provides the timing for promoting the increase in boost pressure and the timing for suppressing the increase in boost pressure, it suppresses overshoot while quickly increasing the boost pressure. can do. Therefore, it is possible to improve both the response and convergence of the actual boost pressure in the transient state.
Further, the opening correction amount C to correct the waste gate opening D in the closing direction, as shown in FIG. 6 (a), provided primarily by the first pressure difference DP _1. On the other hand, the opening correction amount C for correcting the waste gate opening D in the opening direction is mainly given by the second pressure difference DP _{2 as shown} in FIG.

  In this way, the operation of the waste gate opening D is precisely made different from the parameter that provides the correction amount for closing the waste gate opening D, and the parameter that provides the correction amount for opening the waste gate opening D. Can be controlled. Specifically, the timing for closing the waste gate opening degree D and the correction amount thereof, and the opening timing and the correction amount thereof can be controlled independently. Therefore, it is possible to improve both the response and convergence of the actual boost pressure in the transient state.

[7. Modified example]
Regardless of the embodiment described above, various modifications can be made without departing from the spirit of the invention. Each structure of this embodiment can be selected as needed, or may be combined appropriately.

In the above embodiment, the second method is described in detail among the two types of setting methods related to the opening correction amount C. However, the opening correction amount C may be set using the first method. That is, the opening degree correction amount C is set based on the difference between the single filter value and the target boost pressure. In this case, the filter value to be used can be arbitrarily set as long as it corresponds to the operating state of the engine 10 at that time. For example, as shown in FIG. 8B, the opening correction amount C may be set using only the first filter value P _B in the above-described embodiment. The relationship between the opening correction amount C and the first pressure difference DP ₁ can be given by a map, a mathematical expression, or a function as shown in FIG. In this case, as shown by a broken line in the figure, if the opening correction amount C is partially a positive value within the range where the first pressure difference DP ₁ is equal to or less than the predetermined value A ₁ , the response of the boost pressure The overshoot can be suppressed while improving the performance.

Further, as shown in FIG. 8 (c), it may set the opening correction amount C using only the second filter value P _C in the above embodiment. The relationship between the opening correction amount C and the second pressure difference DP ₂ can be given by a map, a mathematical expression, or a function as shown in FIG. Again, as shown by the broken line in the figure, in the range the second pressure difference DP ₂ exceeding a third predetermined value A _3, if the opening correction amount C and a negative value, the responsiveness of boost pressure Overshoot can be suppressed while improving the above.

In the above-described embodiment, the opening correction amount C is calculated based on the difference between the filter value simulating the transient response delay and the virtual boost pressure. However, instead of these “differences”, “ The calculation configuration may be such that the opening correction amount C is calculated using the “ratio”. If either the filter value or the virtual boost pressure is known, these ratios can be uniquely converted into differences. Therefore, even when “ratio” is used instead of “difference”, the same effects as those of the above-described embodiment can be obtained.
In addition, the kind of the engine 10 in the above-mentioned embodiment is arbitrary, A gasoline engine, a diesel engine, and another combustion type engine can be used.

DESCRIPTION OF SYMBOLS 1 Engine control apparatus 2 Setting part (setting means)
2a Required torque setting unit 2b Virtual supercharging pressure setting unit 3 Filter value calculation unit (filter value calculation means)
3a First filter value calculation unit (first filter value calculation means)
3b Second filter value calculation unit (second filter value calculation means)
4 Wastegate control unit 4a Constant-time opening calculation unit (steady-state opening calculation means)
4b Opening correction amount calculation unit (opening correction amount calculation means)
4c Control signal output unit 5 Throttle control unit
P _A Virtual supercharging pressure
P _B First filter value
P _C second filter value
R Constant opening
C Opening correction amount
D Wastegate opening
DP ₁ first pressure differential
DP ₂ second pressure differential

Claims (7)

In the engine control device that controls the boost pressure by adjusting the opening of the waste gate valve,
Setting means for setting a virtual supercharging pressure in response to an output request to the engine;
A filter value calculating means for calculating a filter value obtained by performing a filter process simulating a transient response delay of the supercharging pressure with respect to the virtual supercharging pressure set by the setting means;
A steady-state opening degree calculation means for calculating a wastegate opening degree of the wastegate valve that generates the virtual boost pressure set by the setting means as a steady-state opening degree;
An opening for calculating a correction amount of the wastegate opening relative to the steady-state opening based on a difference between the virtual supercharging pressure set by the setting means and the filter value calculated by the filter value calculating means Correction amount calculating means;
An engine control device comprising: The filter value calculation means has first filter value calculation means for calculating a first filter value subjected to filter processing that simulates a transient response delay in the fully closed state of the waste gate valve as the filter value,
2. The engine control device according to claim 1, wherein the opening degree correction amount calculating means calculates the correction amount based on a difference between the virtual supercharging pressure and the first filter value. The opening degree correction amount calculating means corrects the waste gate opening degree in a closing direction when a difference between the virtual supercharging pressure and the first filter value is a predetermined value or more. Item 3. The engine control device according to Item 2. The filter value calculation means has second filter value calculation means for calculating a second filter value subjected to filter processing that simulates a transient response delay in a fully open state of the waste gate valve as the filter value,
The opening degree correction amount calculating means calculates the correction amount based on a difference between the virtual supercharging pressure and the first filter value and a difference between the virtual supercharging pressure and the second filter value. The engine control device according to claim 2 or 3, wherein The opening degree correction amount calculating means has a difference between the virtual boost pressure and the first filter value less than a predetermined value, and a difference between the virtual boost pressure and the second filter value is a second predetermined value. 5. The engine control device according to claim 4, wherein when the value is equal to or greater than the value, the waste gate opening is corrected in an opening direction. The filter value calculation means performs the filter process using a time constant set based on an intake air amount and an engine rotation speed of the engine. The engine control device according to Item. The opening correction amount calculation means corrects the waste gate opening in the opening direction from the steady-state opening according to the difference between the virtual supercharging pressure and the filter value, and the waste correction amount calculating means. The engine control device according to any one of claims 1 to 6, further comprising a map that gives a negative correction amount for correcting a gate opening degree in a closing direction with respect to the steady-state opening degree.

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