JP2006125352A - Controller for internal combustion engine with supercharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate excessive shortage of torque when performing transient operation of an internal combustion engine to improve drivability. <P>SOLUTION: A turbocharger 30 is provided in an intake pipe 11 of the engine 10, and a throttle valve 14 is provided on its downstream side. A bypass passage 36 is provided between an upstream side part and a downstream side part of an exhaust pipe 24 across a turbine wheel 32 of the turbocharger 30, and a waste gate valve 37 as a supercharging condition variable means is provided in the bypass passage 36. An ECU 50 sets first target torque for controlling the throttle valve 14 and second target torque for controlling the waste gate valve 37 individually when the engine 10 is in a transient operation condition. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

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

  Conventionally, various internal combustion engines provided with a supercharger such as a turbocharger have been put into practical use. The operation of this supercharger improves intake efficiency and improves the output of the internal combustion engine. Further, in such an internal combustion engine with a supercharger, a configuration including a supercharging state variable device for adjusting a supercharging state of the supercharger has been proposed, and one of them is a turbine wheel provided in an exhaust pipe. There is a technique in which a bypass passage is provided so as to bypass the valve, and a waste gate valve is provided in the bypass passage. By operating the wastegate valve, the supercharging pressure can be controlled to the target supercharging pressure in each case.

  By the way, during the transient operation of the internal combustion engine, it is considered that the supercharged state of the supercharger is changed according to the transient operation state. For example, in Patent Document 1, when the supercharging pressure increase execution condition is satisfied during transient operation of the internal combustion engine, the supercharging pressure by the supercharger is controlled to a higher supercharging pressure than the target supercharging pressure, and When the supercharging pressure attenuation execution condition is satisfied, the high side supercharging pressure is controlled to be gradually attenuated to the target supercharging pressure. As a result, the output at the time of transient operation is improved to improve the followability, and the driving feeling of the vehicle is improved.

  However, in the case of the above-mentioned Patent Document 1, it is considered that the supercharging pressure is assumed to be a high side supercharging pressure during transient operation, and the high side supercharging pressure is not necessarily an optimum amount. That is, since the boost pressure is expected to rise, unexpected torque fluctuations occur depending on the operating conditions and the like each time. Therefore, there are cases where the desired running feeling (drivability) cannot be obtained, and an improvement thereof is desired.

In recent years, it has been considered to adopt so-called torque-based control in a vehicle control system that performs various types of vehicle control using torque as a unified parameter. Allocation is to be made. In such a case, the torque adjustment / distribution cannot be properly performed with the configuration in which the supercharging state is controlled as described above. As a result, excessive or insufficient torque may occur, which may lead to deterioration of drivability.
JP-A-6-146913

  The main object of the present invention is to provide a control device for an internal combustion engine with a supercharger that can eliminate excess and deficiency of torque during transient operation of the internal combustion engine and thereby improve drivability. is there.

  In the present invention, when the internal combustion engine is in a specific operating state, the first target torque for controlling the air amount adjusting means (for example, the throttle valve) and the supercharging state varying means (for example, the waste gate valve) are controlled. Are set individually. Thus, unlike the case where the air amount adjusting means and the supercharging state varying means are controlled based on a common target torque, for example, the air amount and the supercharging state (supercharging pressure) according to the transient operation state each time. ) And can be controlled appropriately. In this case, both the air amount adjusting means and the supercharging state varying means are controlled using torque as a basic parameter, so that unexpected torque fluctuations can be suppressed. Accordingly, it is possible to eliminate excess and deficiency of torque during transient operation of the internal combustion engine, thereby improving drivability.

  For example, the first target torque and the second target torque may be set individually when the operating state of the internal combustion engine is in a transient state.

  When the operating state of the internal combustion engine is in a transient state, the first target torque is set to a torque value that matches the driver request, whereas the second target torque is increased by a transient amount with respect to the first target torque. The torque value is good. That is, only the second target torque is increased at the time of transition, and the supercharging state varying means is controlled by this second target torque, so that the boost pressure increase at the time of transient operation can be accelerated. At this time, the first target torque is not increased during the transition, and has a torque value that matches the driver request. Therefore, the air amount does not become excessive, and torque overshoot can be suppressed.

  Here, it is preferable to calculate an increase in transient amount of the second target torque based on the relationship between the driver request torque and the actual torque (for example, the ratio of both torques, the difference between the two torques, etc.). Specifically, the amount of increase during transient is increased as the torque ratio (= actual torque / driver required torque) decreases. Alternatively, it is preferable to calculate an increase in transient amount of the second target torque based on the change amount of the driver request torque. Specifically, the amount of increase during transient is increased as the change amount of the driver request torque is larger.

In an internal combustion engine in which intake air is supercharged on the upstream side of the throttle, the throttle upstream pressure changes depending on the supercharging state, and the change in the throttle upstream pressure causes the passing air amount to change even at the same throttle opening. Therefore, in throttle control, based on the relationship between the upstream and downstream pressures of the throttle valve (for example, pressure ratio = throttle downstream pressure / throttle upstream pressure) and the target air amount calculated from the first target torque. The target opening of the throttle valve is calculated. In this case, in particular, the throttle upstream pressure used as the target throttle opening calculation parameter is preferably determined as follows.
(1) As a calculation parameter for the target throttle opening, an intermediate value between the target throttle upstream pressure and the actual throttle upstream pressure, which are calculated based on the engine operating state each time, is used.
(2) As a parameter for calculating the target throttle opening, a value obtained by subjecting the target throttle upstream pressure calculated based on the engine operating state in each case to a smoothing process is used.
(3) As a parameter for calculating the target throttle opening, a value obtained by pre-reading the actual change in the throttle upstream pressure is used.

  According to each of the above-described configurations, the behavior of the throttle valve has a low response to the actual change in the throttle upstream pressure during the transient operation of the internal combustion engine. Therefore, torque overshoot can be more reliably suppressed. In the case where the target throttle upstream pressure is smoothed as in (2) above, the actual throttle upstream pressure may be set as a guard value. Further, when the change in the actual throttle upstream pressure is prefetched as in (3) above, the target throttle upstream pressure may be set as a guard value.

  The transient target air amount is calculated based on the torque value obtained by increasing the transient amount with respect to the first target torque during the transient operation of the internal combustion engine, and the target calculated based on the transient target air amount is calculated. The throttle upstream pressure may be used as a parameter for calculating the target throttle opening. In this case, since the transient target air amount is used as a calculation parameter for the target throttle upstream pressure, the transient operation is performed as compared with the case where the target air amount calculated based on the first target torque (the target torque not increased during the transient) is used. Responsiveness to the state is improved.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS An embodiment of the invention will be described below with reference to the drawings. In the present embodiment, an engine control system is constructed for an in-vehicle multi-cylinder gasoline engine that is an internal combustion engine, and the engine of the control system is provided with a turbocharger as supercharging means. First, an overall schematic configuration diagram of the engine control system will be described with reference to FIG.

  In the engine 10 shown in FIG. 1, the intake pipe 11 is provided with a throttle valve 14 (air amount adjusting means) whose opening is adjusted by a throttle actuator 15 such as a DC motor. The throttle actuator 15 incorporates a throttle opening sensor for detecting the throttle opening. An intake pressure sensor 12 that detects an intake pressure upstream of the throttle and an intake air temperature sensor 13 that detects the intake air temperature are provided upstream of the throttle valve 14.

  A surge tank 16 is provided on the downstream side of the throttle valve 14, and an intake pressure sensor 17 for detecting the intake pressure on the downstream side of the throttle is provided in the surge tank 16. The surge tank 16 is connected to an intake manifold 18 that introduces air into each cylinder of the engine 10. In the intake manifold 18, an electromagnetically driven fuel injection that injects fuel near the intake port of each cylinder. A valve 19 is attached.

  An intake valve 21 and an exhaust valve 22 are respectively provided in the intake port and the exhaust port of the engine 10, and an air / fuel mixture is introduced into the combustion chamber 23 by the opening operation of the intake valve 21, and the exhaust valve 22. By the opening operation, the exhaust gas after combustion is discharged to the exhaust pipe 24. A spark plug 25 is attached to the cylinder head of the engine 10 for each cylinder, and a high voltage is applied to the spark plug 25 at a desired ignition timing through an ignition device (not shown) including an ignition coil. By applying this high voltage, a spark discharge is generated between the opposing electrodes of each spark plug 25, and the air-fuel mixture introduced into the combustion chamber 23 is ignited and used for combustion.

  The cylinder block of the engine 10 includes a water temperature sensor 26 that detects the temperature of engine cooling water, and a crank that outputs a rectangular crank angle signal at every predetermined crank angle (for example, at a cycle of 30 ° CA) as the engine 10 rotates. An angle sensor 27 is attached.

  A turbocharger 30 is disposed between the intake pipe 11 and the exhaust pipe 24. The turbocharger 30 has a compressor impeller 31 provided in the intake pipe 11 and a turbine wheel 32 provided in the exhaust pipe 24, which are connected by a rotary shaft 33. A bypass passage 34 is provided between the upstream portion and the downstream portion of the intake pipe 11 with the compressor impeller 31 interposed therebetween, and an air bypass valve (ABV) 35 is provided in the bypass passage 34. Further, a bypass passage 36 is provided between an upstream portion and a downstream portion of the exhaust pipe 24 with the turbine wheel 32 interposed therebetween, and a waste gate valve (WG) 37 is provided in the bypass passage 36.

  In the turbocharger 30, the turbine wheel 32 is rotated by the exhaust gas flowing through the exhaust pipe 24, and the rotational force is transmitted to the compressor impeller 31 via the rotation shaft 33. The intake air flowing through the intake pipe 11 is compressed by the compressor impeller 31 to perform supercharging. In this case, when the air bypass valve 35 is opened, the compressed pressure on the downstream side of the turbocharger is released, and the supercharging pressure is controlled. Further, the waste gate valve 37 is opened, so that excessive supercharging pressure is prevented from being generated.

  Here, the wastegate valve 37 functions as a supercharging state varying means, and is configured to be able to adjust the supercharging state from an arbitrary state. An example of the configuration will be briefly described. The wastegate valve 37 includes a diaphragm-type movable portion and a pressure control valve (vacuum switching valve) for adjusting the pressure of the pressure chamber defined by the diaphragm. An actuator is attached. An intake pipe pressure (that is, a supercharging pressure) downstream of the compressor impeller 31 is introduced into the pressure chamber, and the pressure acting on the pressure chamber is controlled by the ECU 50 being duty-controlled by the pressure control valve. Thereby, the wastegate valve 37 is displaced, and the supercharging state is adjusted.

  In this case, if the control duty ratio is small and the pressure control valve is closed, the intake pipe pressure directly acts on the pressure chamber. Therefore, the wastegate valve 37 operates according to the supercharging pressure. That is, when the supercharging pressure increases and the intake pipe pressure rises, the pressure in the pressure chamber rises, and accordingly, the wastegate valve 37 operates to the open side and the turbine power decreases. As the turbine power decreases, the compressor power also decreases, and the supercharging pressure decreases. Conversely, when the control duty ratio is large and the pressure control valve is opened, the pressure acting on the pressure chamber is reduced accordingly. Therefore, even if the supercharging pressure increases and the intake pipe pressure rises, the pressure in the pressure chamber does not rise, and the wastegate valve 37 is kept closed. Therefore, even if the supercharging pressure increases, the turbine power is maintained, and the supercharging pressure is maintained or the supercharging pressure is increased.

  The air supercharged by the turbocharger 30 is cooled by the intercooler 38 and then fed downstream. As the intake air is cooled by the intercooler 38, the charging efficiency of the intake air is increased.

  Further, on the upstream side of the turbocharger 30, an air flow meter 41 for detecting the intake air amount and an intake air temperature sensor 42 for detecting the intake air temperature in the intake upstream portion are provided. In addition, the present control system is provided with an accelerator opening sensor 43 that detects an accelerator pedal depression amount (accelerator opening) and an atmospheric pressure sensor 44 that detects atmospheric pressure.

  As is well known, the ECU (electronic control unit) 50 is mainly composed of a microcomputer composed of a CPU, ROM, RAM, etc., and by executing various control programs stored in the ROM, the engine operating state can be changed each time. In response, various controls of the engine 10 are performed. That is, detection signals are input to the ECU 50 from the various sensors described above. The ECU 50 calculates the fuel injection amount, the ignition timing, and the like based on various detection signals that are input as needed, and controls the drive of the fuel injection valve 19 and the spark plug 25.

  In this embodiment, so-called torque-based control is adopted in various types of vehicle control. For example, in electronic throttle control, the throttle opening is controlled to a target value using the driver-requested torque as a basic parameter. In brief, the ECU 50 calculates the target air amount based on the required torque calculated based on the accelerator opening and the like, and calculates the target throttle opening based on the target air amount. Then, a desired air amount control is performed by driving the throttle actuator 15 based on the target throttle opening.

  Note that in this vehicle, control is performed using torque as a unified parameter in a similar manner other than throttle control. For example, torque base control is also performed in transmission control, cruise control, and the like. By using the torque as a unified parameter in this way, it is possible to share parameters for engine control and other vehicle control, and the cooperation of each control is enhanced. There is also an advantage that control can be easily applied to different vehicles and engines.

  Next, the control content realized by the ECU 50 will be described. FIG. 2 is a functional block diagram showing calculation logic relating to target throttle opening calculation and target WG opening calculation. The target throttle opening and target WG opening (target wastegate valve opening) are calculated by this logic. The In this case, the target throttle opening is calculated based on the following basic formula (1) for calculating the throttle passage intake air amount Ga.

Ga = f (Thr) × Pb / √T × f (Pm / Pb) (1)
In equation (1), Thr is the throttle opening, Pb is the throttle upstream pressure, Pm is the throttle downstream pressure, and T is the intake air temperature. However, in FIG. 2, the basic throttle-passing intake air amount Ga is the target air amount, the throttle opening Thr is the target throttle opening, the throttle upstream pressure Pb is the intermediate target throttle upstream pressure, and the throttle downstream pressure Pm is the target throttle. The target throttle opening is calculated based on the target air amount, the intermediate target throttle upstream pressure, the target throttle downstream pressure, and the like.

  In detail, the target air amount calculation unit 51 calculates the target air amount using the engine speed, the target torque, and the intake air temperature as parameters. The target torque corresponds to the driver request torque corresponding to the driver's accelerator operation, and is calculated based on the engine speed, the accelerator opening, and the like.

  Further, the intermediate target throttle upstream pressure calculation unit 52 calculates the intermediate target throttle upstream pressure based on the target throttle upstream pressure and the actual throttle upstream pressure. Here, the target throttle upstream pressure is calculated based on the target air amount and the engine speed each time, for example, using the relationship shown in FIG. The actual throttle upstream pressure is calculated based on the detection signal of the intake pressure sensor 12. FIG. 3 shows a configuration example of the calculation unit 52. In FIG. 3, an intermediate target throttle upstream pressure calculation unit 52 calculates a pressure deviation between the target throttle upstream pressure and the actual throttle upstream pressure. Further, a pressure ratio correction value is calculated using the engine speed, load (intake air amount), ABV execution flag, and accelerator opening as parameters. Specifically, for example, the pressure ratio correction value is calculated based on the intake air amount and the engine speed using the relationship shown in FIG. According to FIG. 5, the smaller the intake air amount, the larger the pressure ratio correction value. Conversely, the larger the intake air amount, the smaller the pressure ratio correction value. However, the maximum value of the pressure ratio correction value is 1. Further, when calculating the pressure ratio correction value, a transient determination is made based on the accelerator opening, and if the pressure ratio correction value is in a steady state, the pressure ratio correction value is set to zero. Further, it is determined whether or not the air bypass valve 35 is open based on the ABV execution flag. If the air bypass valve 35 is open (if the ABV execution flag = ON), the pressure ratio correction value is set to 0. . Since the cause of the response delay of the throttle downstream pressure is the control response delay of the intake system volume and the throttle valve 14, the characteristics shown in FIG. 5 should be set reflecting the control response of the intake system volume and the throttle valve. .

  Then, the actual throttle upstream pressure is added to the product of the pressure deviation and the pressure ratio correction value to calculate the intermediate target throttle upstream pressure. At this time, the pressure ratio correction value determines how much the intermediate target throttle upstream pressure is set to the target throttle upstream pressure side or the actual throttle upstream pressure side. For the intermediate target throttle upstream pressure, upper and lower limit guards are implemented with the actual throttle upstream pressure and the target throttle upstream pressure as the upper limit value and the lower limit value, respectively (the larger of the actual throttle upstream pressure and the target throttle upstream pressure). Is the upper limit, and the smaller is the lower limit). As described above, the intermediate target throttle upstream pressure calculation unit 52 calculates the intermediate target throttle upstream pressure between the target throttle upstream pressure and the actual throttle upstream pressure.

  Further, the pressure ratio calculation unit 53 calculates a pressure ratio between the intermediate target throttle upstream pressure and the target throttle downstream pressure (= target throttle downstream pressure / intermediate target throttle upstream pressure). At this time, the target throttle downstream pressure is calculated based on the target air amount and the engine speed each time, for example, using the relationship of FIG.

  The target throttle opening calculation unit 54 calculates the target air amount calculated by the target air amount calculation unit 51, the intermediate target throttle upstream pressure calculated by the intermediate target throttle upstream pressure calculation unit 52, and the pressure ratio calculation unit 53. The target throttle opening is calculated based on the pressure ratio.

  On the other hand, regarding the calculation of the target WG opening, a target torque for WG control (hereinafter referred to as WG target torque) is newly calculated. The target WG opening is calculated based on this WG target torque. That is, a transient torque is set at the time of transition such as during vehicle acceleration, and the WG target torque calculation unit 55 calculates the WG target torque by adding the target torque and the transient torque. The transient torque is calculated based on, for example, the relationship shown in FIG. According to FIG. 6, the torque ratio (= estimated torque / target torque) between the estimated torque and the target torque is used as a parameter, and the transient torque is calculated as a smaller value as the torque ratio is larger. Further, the larger the intake air amount, the smaller the transient torque is calculated. The estimated torque is obtained by estimating the actual torque, and is calculated based on, for example, the engine speed and the intake air amount. At this time, a larger value is calculated as the estimated torque as the engine speed is higher or as the intake air amount is larger. If it is not a transition time, transient torque = 0, and target torque = WG target torque.

  The WG target throttle upstream pressure calculation unit 56 calculates a WG target throttle upstream pressure (a boost pressure targeted by the WG opening control) based on the WG target torque. At this time, the same processing as when the target throttle upstream pressure for throttle control is calculated may be performed, the target air amount for WG control is calculated based on the target torque for WG, and the relationship of FIG. 4 is used. The WG target throttle upstream pressure is calculated based on the target air amount.

  The target WG opening calculation unit 57 calculates the target WG opening based on the WG target throttle upstream pressure, for example, using the relationship shown in FIG. In FIG. 7, a relationship is set such that the target WG opening becomes smaller as the WG target throttle upstream pressure increases. In the present embodiment, the target torque (driver required torque) corresponds to the “first target torque”, and the WG target torque corresponds to the “second target torque”.

  FIG. 8 is a flowchart showing a calculation procedure of the target throttle opening, and this process is executed by the ECU 50 at a predetermined time cycle (for example, 8 msec cycle).

  In step S101, the target air amount is calculated based on the engine speed, the target torque, and the like. In step S102, a pressure ratio correction value is calculated using the engine speed, load (intake air amount), ABV execution flag, and accelerator opening as parameters. In step S103, the target throttle upstream pressure is calculated based on the target air amount and the engine speed. In step S104, the target throttle downstream pressure is calculated based on the target air amount and the engine speed. In step S105, the intermediate target throttle upstream pressure is calculated based on the target throttle upstream pressure, the actual throttle upstream pressure, and the pressure ratio correction value.

  Finally, in step S106, target throttle opening is performed based on the target air amount, intermediate target throttle upstream pressure, throttle upstream and downstream pressure ratio (= target throttle downstream pressure / intermediate target throttle upstream pressure), and throttle upstream intake air temperature. Calculate the degree.

  FIG. 9 is a flowchart showing a procedure for calculating the target WG opening, and this process is executed by the ECU 50 at a predetermined time period (for example, 8 msec period), as in the process of FIG. For example, it is executed subsequent to the processing of FIG.

  In FIG. 9, in step S201, the estimated torque (actual torque) is calculated based on the engine speed and the intake air amount, and in the subsequent step S202, the estimated torque and the target torque (calculated value in step S101 of FIG. 8). The torque ratio is calculated from

  Thereafter, in step S203, transient determination is performed depending on whether the torque ratio is equal to or less than a predetermined value. The predetermined value is a value less than 1, and is 0.5 in the present embodiment. If the torque ratio ≦ predetermined value, it is determined that the transition is in progress, and the process proceeds to step S204. In step S204, a transient torque is calculated based on the relationship shown in FIG. If the torque ratio is greater than the predetermined value, it is considered that there is no transient state, or even if it is a transient level, the level is considered to be minor, and the process proceeds to step S205 to reset the transient torque (transient torque = 0).

  Thereafter, in step S206, the target torque for WG is calculated by adding the target torque and the transient torque. Further, in step S207, the WG target throttle upstream pressure is calculated based on the WG target torque, and in step S208, the target WG opening is calculated based on the WG target throttle upstream pressure.

  FIG. 10 is a time chart showing the state of throttle opening control and WG opening control during transient operation of the engine 10. In FIG. 10, the behavior of the target value is indicated by a one-dot chain line, and the behavior of the actual value is indicated by a solid line. In the chart portion showing the throttle upstream pressure in (b), the intermediate target throttle upstream pressure is indicated by a dotted line.

  In FIG. 10, at timing t <b> 1, the target torque increases with an acceleration operation by the driver (see (a)). Further, the transient torque is calculated according to the transient operation state at that time, and the WG target torque (= target torque + transient torque) is calculated as shown (see (e)). At this time, with respect to the throttle opening control, the target throttle upstream pressure and the target throttle downstream pressure increase as the target air amount (not shown) increases as the target torque increases (see (b) and (c)). ). The actual throttle upstream pressure and the actual throttle downstream pressure change as illustrated with a delay from the target value. Then, an intermediate target throttle upstream pressure is calculated between the target throttle upstream pressure and the actual throttle upstream pressure (see (b)). Based on this intermediate target throttle upstream pressure, other target throttle downstream pressure, target air amount, and the like. The throttle opening is controlled by the calculated target throttle opening (see (d)).

  On the other hand, regarding the WG opening control, the WG target throttle upstream pressure is calculated based on the WG target torque, and further the target WG opening is calculated based on the WG target throttle upstream pressure. The WG opening is controlled by the control duty corresponding to the target WG opening. At this time, the hatched portion in the figure indicates that the wastegate valve 37 is controlled to be closed more in accordance with the transient operation state of the engine, and accordingly, the supercharging pressure rises quickly.

  According to the embodiment described above in detail, the following excellent effects can be obtained.

  Since the target torque for throttle opening control and the target torque for WG opening control are individually set when the engine is in a transient operation state, each control is performed based on the common target torque. Unlike the case where it carries out, it becomes possible to appropriately control the air amount and the supercharging state (supercharging pressure) according to the transient operation state each time. In this case, both throttle opening control and WG opening control are performed using torque as a basic parameter, so that unexpected torque fluctuations can be suppressed. Therefore, it is possible to eliminate the excess or deficiency of torque during the transient operation of the engine, thereby improving drivability.

  While the target torque for throttle opening control is the driver required torque, the target torque for WG opening control is the torque obtained by increasing the transient for the driver required torque. The increase in supply pressure can be accelerated. Therefore, acceleration performance is improved. In this case, if the target torque for throttle control is also increased during transition, it is considered that the air amount becomes excessive and torque overshoot occurs. However, according to the present embodiment, such inconvenience can be solved.

  In throttle control, the intermediate target throttle upstream pressure is set between the target throttle upstream pressure and the actual throttle upstream pressure, and the target throttle opening is calculated based on the intermediate target throttle upstream pressure. At times, the behavior of the throttle valve 14 becomes less responsive to changes in the actual throttle upstream pressure. Therefore, torque overshoot can be more reliably suppressed.

  In addition, this invention is not limited to the content of description of the said embodiment, For example, you may implement as follows.

  In the above embodiment, the calculation logic related to the target throttle opening calculation and the target WG opening calculation is configured as shown in FIG. 2, but this may be changed as shown in FIGS. 11 and 12. In FIG. 11, the intermediate target throttle upstream pressure calculation unit 52 is eliminated as the difference from FIG. 2 and the pressure ratio calculation unit 53 uses the pressure ratio between the actual throttle upstream pressure and the target throttle downstream pressure (= target throttle downstream pressure / actual (Throttle upstream pressure) is calculated. Even in this configuration, when the engine is in a transient operation state, the target torque for throttle opening control and the target torque for WG opening control are individually set, so that each transient operation state Accordingly, the air amount and the supercharging state (supercharging pressure) can be appropriately controlled. Therefore, it is possible to eliminate the excess or deficiency of torque during the transient operation of the engine, thereby improving drivability. However, from the viewpoint of suppressing torque overshoot, it can be said that FIG. 2 is superior.

  Further, in FIG. 12, as a difference from FIG. 2, the target throttle upstream pressure calculation unit 61 calculates the target throttle upstream pressure using the added torque of the target torque and the transient torque (transient target torque) as a parameter. The intermediate target throttle upstream pressure calculation unit 52 calculates the intermediate target throttle upstream pressure based on the target throttle upstream pressure calculated by the target throttle upstream pressure calculation unit 61. That is, at this time, the transient target air amount is calculated based on the torque value obtained by increasing the transient amount, and the target throttle upstream pressure (corresponding to the base target value) calculated based on the transient target air amount is calculated. The intermediate target throttle upstream pressure is calculated so as to change to a low response.

  The operation in the case of the configuration shown in FIG. 12 is shown in the time chart of FIG. In FIG. 13, the behavior of the target value is indicated by a one-dot chain line, and the behavior of the actual value is indicated by a solid line. In the chart portion showing the throttle upstream pressure in (b), the intermediate target throttle upstream pressure is indicated by a dotted line.

  In FIG. 13, at timing t <b> 11, the target torque increases with an acceleration operation by the driver or the like (see (a)). In the figure, the target torque obtained by adding the transient torque (hatched portion) is shown. At this time, the calculation of the target air amount and the calculation of the target throttle upstream pressure (see (b)) are performed based on the target torque obtained by adding the increase amount during the transition. Then, an intermediate target throttle upstream pressure is calculated between the target throttle upstream pressure and the actual throttle upstream pressure (see (b)). Based on this intermediate target throttle upstream pressure, other target throttle downstream pressure, target air amount, and the like. The throttle opening is controlled by the calculated target throttle opening (see (d)). On the other hand, the WG opening degree control is equivalent to FIG.

  In this case, the transient target air amount (transient increase torque) is used as a parameter for calculating the target throttle upstream pressure. Therefore, transient operation is performed compared to the case where the target air amount calculated based on the target torque that has not increased during the transient is used. Responsiveness to the state is improved. Further, since the intermediate target throttle upstream pressure is increased, the throttle valve 14 is controlled on the closed side as compared with FIG. 10, and torque overshoot can be more reliably suppressed.

  In the above embodiment, the intermediate target throttle upstream pressure (throttle upstream pressure used as a target throttle opening calculation parameter) is calculated as an intermediate value between the target throttle upstream pressure and the actual throttle upstream pressure. You may do it. For example, a value obtained by performing a smoothing process on the target throttle upstream pressure may be used as a target throttle opening calculation parameter, or a value obtained by pre-reading a change in the actual throttle upstream pressure may be used as a target throttle opening calculation parameter. good. Even in such a configuration, during the transient operation of the engine, the behavior of the throttle valve becomes low response to the change in the actual throttle upstream pressure, and the torque overshoot can be more reliably suppressed. When the target throttle upstream pressure is smoothed, the actual throttle upstream pressure should be set as the guard value. When the change in the actual throttle upstream pressure is prefetched, the target throttle upstream pressure is set as the guard value. It is good to keep.

  In the above embodiment, the transient state is determined based on the torque ratio (= estimated torque / target torque), but this may be changed. For example, the transient state may be determined based on the deviation between the estimated torque and the target torque, or the transient state may be determined based on the amount of change in the target torque (driver request torque). When determining the transient state based on the change amount of the target torque, the transient torque is increased as the change amount of the target torque (driver request torque) is larger. In addition, the transient torque can be calculated based on the boost pressure response determined by the intake air amount, the accelerator opening, and the like.

  Further, during the transient operation of the engine, the transient torque may be first calculated based on the torque ratio or the like, and thereafter, the transient torque may be attenuated by a predetermined amount as time passes.

  In the above embodiment, the actual torque is calculated as the estimated torque based on the engine operating state in each case, but instead of this, the actual torque may be detected using a torque sensor or the like.

  The target torque (first target torque) for throttle opening control and the target torque (second target torque) for WG opening control are individually set except when the engine 10 is in a transient operation state. A configuration is also possible.

  A configuration other than the throttle valve may be adopted as the air amount adjusting means. For example, it is possible to adopt a configuration in which the amount of air is adjusted by controlling the operation of the intake valve.

  In the above-described embodiment, the wastegate valve 37 is used as the supercharging state varying means, and the supercharging state is adjusted by controlling the opening degree of the wastegate valve 37. However, this may be changed. For example, an electric motor built in the turbocharger 30 is used as the supercharging state varying means, and the supercharging state is adjusted by controlling the electric motor. In such a case, by setting the target torque for throttle opening control and the target torque for motor control individually, the air amount and the supercharging state (supercharge according to the transient operation state in each case, as described above, are used. Supply pressure) can be controlled appropriately. Therefore, it is possible to eliminate the excess or deficiency of torque during the transient operation of the engine, thereby improving drivability.

It is a block diagram which shows the outline of the engine control system in embodiment of invention. It is a functional block diagram which shows the calculation logic regarding target throttle opening calculation and target WG opening calculation. It is a functional block diagram which shows the structure of an intermediate | middle target throttle upstream pressure calculation part. It is a figure for calculating a target throttle upstream pressure and a target throttle downstream pressure. It is a figure for calculating a pressure ratio correction value. It is a figure for calculating transient torque. It is a figure for calculating the target WG opening. It is a flowchart which shows the calculation process of target throttle opening. It is a flowchart which shows the calculation process of the target WG opening degree. It is a time chart which shows the mode of throttle opening control and WG opening control at the time of engine transient operation. It is a functional block diagram which shows the calculation logic regarding target throttle opening calculation and target WG opening calculation. It is a functional block diagram which shows the calculation logic regarding target throttle opening calculation and target WG opening calculation. It is a time chart which shows the mode of throttle opening control and WG opening control at the time of engine transient operation.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Engine, 14 ... Throttle valve, 30 ... Turbocharger, 37 ... Wastegate valve, 50 ... ECU.

Claims (8)

A supercharging unit provided upstream of an air amount adjusting unit provided in the intake system and operating by exhaust energy to compress intake air, and a supercharging state variable for adjusting the supercharging state of the supercharging unit And a control device that controls the operating state of the internal combustion engine based on a target torque according to a driver request.
Separately setting a first target torque for controlling the air amount adjusting means and a second target torque for controlling the supercharging state varying means when the internal combustion engine is in a specific operating state; A control device for an internal combustion engine with a supercharger.   When the operating state of the internal combustion engine is in a transient state, the first target torque is set to a torque value that matches a driver request, whereas the second target torque is increased in a transient amount with respect to the first target torque. The control device for an internal combustion engine with a supercharger according to claim 1, wherein the torque value obtained by performing the above is set.   The control device for an internal combustion engine with a supercharger according to claim 2, wherein an increase in transient amount of the second target torque is calculated based on a relationship between a driver request torque requested by the driver and an actual torque.   3. The control device for an internal combustion engine with a supercharger according to claim 2, wherein a transient increase amount of the second target torque is calculated based on a change amount of a driver request torque requested by the driver. A throttle valve is provided as the air amount adjusting means, and the target throttle opening is calculated based on the relationship between the upstream and downstream pressures of the throttle valve and the target air amount calculated from the first target torque. A control device,
5. The intermediate value between the target throttle upstream pressure and the actual throttle upstream pressure calculated based on the engine operating state each time is used as the target throttle opening calculation parameter. The control apparatus of the internal combustion engine with a supercharger according to any one of the above. A throttle valve is provided as the air amount adjusting means, and the target throttle opening is calculated based on the relationship between the upstream and downstream pressures of the throttle valve and the target air amount calculated from the first target torque. A control device,
5. The value obtained by subjecting the target throttle upstream pressure calculated based on the engine operating state in each case to a smoothing process as the target throttle opening calculation parameter. The control apparatus of the internal combustion engine with a supercharger as described. A throttle valve is provided as the air amount adjusting means, and the target throttle opening is calculated based on the relationship between the upstream and downstream pressures of the throttle valve and the target air amount calculated from the first target torque. A control device,
The control device for an internal combustion engine with a supercharger according to any one of claims 1 to 4, wherein a value obtained by pre-reading an actual change in the throttle upstream pressure is used as a calculation parameter for the target throttle opening.   A transient target air amount is calculated based on a torque value obtained by increasing the transient amount with respect to the first target torque during the transient operation of the internal combustion engine, and a target throttle calculated based on the transient target air amount is calculated. The control device for an internal combustion engine with a supercharger according to any one of claims 5 to 7, wherein an upstream pressure is used as a calculation parameter for the target throttle opening.

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