JP4434057B2 - Supercharging pressure control device for internal combustion engine - Google Patents

Description

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

  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 the supercharging state of the supercharger has been proposed, and one of them is an exhaust turbine provided in an exhaust pipe. There is a technique in which a bypass passage is provided so as to bypass the valve and a wastegate valve is provided in the bypass passage. The operation of the waste gate valve adjusts the exhaust gas flow rate flowing into the exhaust turbine, thereby suppressing an excessive increase in the supercharging pressure.

  In the waste gate valve, when a change with time occurs due to long-term use, even if the same control amount is given to the drive actuator of the waste gate valve, a difference occurs in the actual waste gate valve opening. Therefore, it is considered to change the control amount of the wastegate valve according to the change with time. For example, in Patent Document 1, when the engine rotation speed and the engine load are in a predetermined range (that is, in the acceleration mode), a wastegate valve control signal is learned.

  Further, in Patent Document 2, in a configuration in which the opening degree of the wastegate valve is feedback-controlled by the duty ratio, an appropriately high value is set as the upper limit guard value from the required duty ratio defined corresponding to the engine rotation speed during steady operation. On the other hand, the value of the required duty ratio at a predetermined engine speed is learned in the actual operating state, and the upper limit guard value at each engine speed is calculated from the learned value and a preset map. As a result, overshoot and control delay during feedback control are eliminated.

However, the difference in the opening degree of the wastegate valve varies depending on factors such as a temperature change in the wastegate valve and its drive system in addition to a steady factor due to a change with time. Therefore, in the above-described conventional technique, it is considered that a learning error occurs due to a temperature change in the wastegate valve or its drive system, and as a result, there is a possibility that the supercharging pressure cannot be controlled properly.
Japanese Patent Laid-Open No. 11-218031 Japanese Patent No. 3105402

  The present invention provides a supercharging pressure control device for an internal combustion engine that can correctly learn a reference position of a flow control valve related to supercharging pressure control, such as a wastegate valve, and can appropriately control the supercharging pressure. This is the main purpose.

  A supercharging pressure control device according to the present invention is applied to an internal combustion engine having a turbocharger having an exhaust turbine and an intake compressor, and includes a flow control valve provided in a passage that bypasses the exhaust turbine, or an intake compressor. The opening degree of the flow control valve provided in the bypass path is adjusted based on the reference position of the control valve. By adjusting the opening degree of the flow rate control valve, the flow rate of exhaust gas and intake air flowing through the passage is adjusted, thereby controlling the supercharging pressure. Further, reference position learning means for learning a reference position of the flow control valve is provided, and the reference position learning means learns the reference position after the internal combustion engine is warmed up. The flow control valve provided in the passage that bypasses the exhaust turbine is generally called a wastegate valve (WGV), and the exhaust amount flowing into the exhaust turbine is adjusted by the wastegate valve. The flow control valve provided in the passage that bypasses the intake compressor is generally called an air bypass valve (ABV), and the amount of intake air flowing into the intake compressor is adjusted by the air bypass valve.

  In short, when the warm-up completion of the internal combustion engine is compared with that after the warm-up is completed, a temperature difference occurs in the flow control valve and its drive system, resulting in a reference position learning error. In this regard, according to the present invention, since the reference position is learned after the internal combustion engine is warmed up, a learning error caused by a temperature difference in the flow control valve or its drive system can be eliminated. As a result, it is possible to correctly learn the reference position of the flow rate control valve related to the supercharging pressure control such as the waste gate valve, and to properly control the supercharging pressure.

  Here, in order to be able to arbitrarily control the opening degree of the flow control valve without depending on each supercharging pressure or the like, it is conceivable to employ an electric actuator using an electric motor as a drive source. The flow control valve and the electric actuator are mechanically connected via a connecting member such as a rod. In such a case, the mechanical configuration and the connecting member of the electric actuator expand or contract in accordance with the temperature change, but as described above, the reference position is learned after the internal combustion engine is warmed up, so that the connecting member and the like It is possible to suppress mislearning caused by the expansion and contraction of.

  As a method of supercharging pressure control, an opening correction amount of the flow control valve is calculated based on a target supercharging pressure set according to the operating state of the internal combustion engine and an actual supercharging pressure in each case, and the opening degree It is conceivable to control the opening degree of the flow control valve based on the correction amount. In such a configuration, the reference position may be learned based on the calculated opening correction amount. In other words, when a change with time occurs in the flow control valve and its drive system, a steady supercharging pressure deviation occurs, which is reflected in the opening correction amount of the flow control valve. Therefore, the reference position can be learned on the basis of the opening correction amount of the flow control valve.

  In addition to after the internal combustion engine is warmed up, the following conditions (1) to (4) are preferably set as the execution conditions of the reference position learning.

  (1) Provided with a boost pressure control means for performing feedback control so that the actual boost pressure matches the target boost pressure set according to the operating state of the internal combustion engine, and performing the feedback control by the boost pressure control means The reference position is learned on the condition that it is in the middle. When the supercharging pressure feedback control is performed, a deviation of the reference position due to a change over time or the like is reflected as a feedback control amount, and appropriate reference position learning is possible.

  (2) The reference position is learned on the condition that the amount of fluctuation in the opening degree of the flow control valve is larger than a predetermined value. When a change with time or the like occurs in the flow control valve or its drive system, the amount of change in the opening of the flow control valve increases. Therefore, it is possible to determine whether or not the reference position learning is necessary based on the amount of change in the opening of the flow control valve, and the reference position learning can be performed at an appropriate time.

  (3) In the configuration in which it is determined whether or not the pressure in the intake passage is a negative pressure, and the flow control valve is controlled to the fully closed position when it is determined that the pressure in the intake passage is a negative pressure, The reference position is learned on condition that the pressure in the passage is negative. When the pressure in the intake passage becomes negative (that is, lower than atmospheric pressure), even if the flow control valve is fully closed, supercharging is not performed, and the fully closed position can be learned as the reference position of the flow control valve. .

  (4) In the configuration in which it is determined whether or not the rotation of the exhaust turbine is in a predetermined low rotation state, and the flow control valve is controlled to the fully closed position when it is determined that the rotation is in the low rotation state, the rotation of the exhaust turbine The reference position is learned on the condition that is in a low rotation state. When the rotation of the exhaust turbine is low, supercharging is not performed even if the flow control valve is fully closed, and the fully closed position can be learned as the reference position of the flow control valve.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described 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 as an 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. 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 includes a compressor impeller (intake compressor) 31 provided in the intake pipe 11 and a turbine wheel (exhaust turbine) 32 provided in the exhaust pipe 24, which are connected by a rotary shaft 33. Yes. 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 (WGV) 37 is provided in the bypass passage 36.

  The wastegate valve 37 is connected to an actuator 42 (hereinafter referred to as a WGV actuator) with a motor (electric motor) via a rod 41 as a connecting member. By driving the WGV actuator 42, the wastegate valve 37 is opened and closed. Accordingly, the opening area of the bypass passage 36, that is, the exhaust flow rate flowing through the bypass passage 36 is variably adjusted. In this case, the wastegate valve 37 functions as a supercharging state variable means, and is configured to be able to adjust the supercharging pressure in an arbitrary state.

  FIG. 2 is a drawing schematically showing the mechanical configuration of the WGV actuator 42. A motor 43 is disposed in a case (not shown) of the WGV actuator 42, and a motor gear 44 is attached to the tip of the motor rotating shaft 43a. A flat gear 45 is engaged with the motor gear 44, and a worm 46 is connected to a shaft portion of the flat gear 45. Further, a helical gear 47 is provided so as to mesh with the worm 46, and the helical gear 47 is rotatable around a shaft portion 48. An arm 49 that rotates integrally with the helical gear 47 is provided on the shaft portion 48, and a wastegate valve 37 is connected to one end of the arm 49 via a rod 41. A case (not shown) surrounding the helical gear 47 is provided with a WGV opening sensor 50 that detects the WGV opening by detecting the rotational position of the gear 47.

  In the WGV actuator 42 configured as described above, when the motor 43 is energized, the motor gear 44 rotates in either the forward or reverse direction, and the rotation is transmitted to the helical gear 47 via the spur gear 45 and the worm 46. Then, as the helical gear 47 rotates, the rod 41 is interlocked, and as a result, the waste gate valve 37 opens and closes.

  In the configuration using the conventional positive pressure actuator, the WGV opening degree is controlled according to the supercharging pressure. However, by using the electric WGV actuator 42 as described above, the WGV is not dependent on the supercharging pressure. The opening can be set arbitrarily.

  Returning to the description of FIG. 1, in the turbocharger 30, the turbine wheel 32 is rotated by the exhaust gas supplied to the turbine wheel 32, and the rotational force is transmitted to the compressor impeller 31 via the rotating shaft 33. The intake air flowing through the intake pipe 11 is compressed by the compressor impeller 31 to perform supercharging. At this time, a desired supercharging pressure can be realized by opening and closing the wastegate valve 37 based on the engine operating state and the like each time.

  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, in the present control system, an accelerator opening sensor 51 is provided for detecting an accelerator pedal depression operation amount (accelerator opening) by the driver.

  As is well known, the ECU (electronic control unit) 60 is mainly composed of a microcomputer composed of a CPU, ROM, RAM, and the like, and by executing various control programs stored in the ROM, the engine operation state can be changed to each time. In response, various controls of the engine 10 are performed. That is, detection signals are input to the ECU 60 from the various sensors described above. The ECU 60 calculates the fuel injection amount, 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 ignition device.

  Further, the ECU 60 calculates the target throttle opening based on the various detection signals, and performs the desired air amount control by driving the throttle actuator 15 based on the target throttle opening. In this case, in particular, the target air amount is calculated based on the accelerator opening, the target throttle opening is calculated using the target air amount as a parameter, and the throttle opening is controlled based on the target throttle opening. Further, in parallel with the throttle opening control, the ECU 60 performs the WGV opening control so that the required WGV opening is obtained each time. With the throttle opening control and WGV opening control described above, the required torque requested by the driver can be realized.

  Incidentally, the throttle opening, the WGV opening, and the output torque of the engine 10 have the relationship shown in FIG. 3, and according to the figure, the equal torque lines L1 to L4 are defined as shown in the figure. The equal torque lines are L1, L2, L3, L4 in order from the smallest torque.

  For example, the difference when torque control is performed at each point of P1 and P2 on the equal torque line L2 will be described. The torque control at the point P1 corresponds to the conventional control, and the torque control at the point P2 corresponds to the control of the present embodiment. At point P1, WGV opening = a1 (almost fully closed value) and throttle opening = b1, and at point P2, WGV opening = a2 and throttle opening = b2.

  Comparing the torque control at points P1 and P2, the torque opening at point P2 has a larger throttle opening. As a result, as shown in the PV diagram (pressure volume diagram) in FIG. 4, the exhaust pressure is lowered, and as a result, the pump loss is reduced. In FIG. 4, the two-dot chain line indicates the characteristics when the WGV opening is substantially fully closed, and the solid line indicates the characteristics when the WGV opening is opened to a predetermined opening. Therefore, the fuel efficiency improvement effect is obtained by the torque control at the point P2. In the present embodiment, the WGV opening is controlled by an intermediate opening excluding a predetermined fully closed region. Specifically, the WGV opening is controlled within a range of 20 to 100% during the normal operation of the engine 10 (preferably 50 The WGV opening is controlled within a range of ˜80%.

  However, assuming that an acceleration operation is performed, when accelerating from the point P1, the torque can be increased by increasing the throttle opening as shown by an arrow X1 in FIG. On the other hand, in order to increase the torque during acceleration from the point P2, in addition to increasing the throttle opening as shown by the arrow X2 in FIG. 3, it is necessary to reduce the WGV opening. That is, in the present embodiment, the amount of opening / closing operation of the wastegate valve 37 is larger than that in the conventional control. Therefore, considering the response delay of the WGV actuator 42, the response of the supercharging pressure is delayed, and the response of torque control is affected.

  Therefore, in the present embodiment, in order to improve the supercharging pressure response, the target WGV opening is set based on the supercharging pressure deviation that is the difference between the target supercharging pressure and the actual supercharging pressure, and the actual WGV opening. Is made to coincide with the target WGV opening, and the supercharging pressure feedback control is performed. At this time, the WGV opening is controlled based on the fully closed position of the wastegate valve 37.

  On the other hand, when the waste gate valve 37 is controlled by the electric WGV actuator 42 as described above, deposits are accumulated on the valve end face or the like by using these over a long period of time, or rust is generated. As a result, it is considered that a deviation occurs in the fully closed position (reference position) of the waste gate valve 37. Therefore, in the present embodiment, the fully closed position is learned at any time in order to continue appropriate WGV opening control even if the full closed position shift of the wastegate valve 37 due to a change with time occurs, and the learning result is stored in the ECU 60. It is assumed that the data is stored in a non-volatile memory such as an EEPROM provided in the memory.

  In addition to the change over time described above, the cause of the fully closed position deviation of the waste gate valve 37 includes thermal expansion (such as a rod 41 connecting the waste gate valve 37 and the WGV actuator 42, and a case constituting the actuator 42). Or contraction). In this case, the fully closed position shift due to a change with time is steady, whereas the fully closed position shift due to thermal expansion changes depending on the member temperature and the ambient temperature. In order to learn a steady fully closed position shift, it is considered desirable to eliminate the factor due to thermal expansion. Therefore, in this embodiment, the fully closed position is set on the condition that the engine has been warmed up. Perform location learning.

  Here, in the configuration in which the WGV opening is feedback-controlled so that the actual WGV opening coincides with the target WGV opening as described above, the actual WGV opening (sensor detection value), the target WGV opening, The above-mentioned deviation constantly occurs, and at that time, the supercharging pressure deviation also constantly occurs. Therefore, the WGV fully closed learning value is calculated by the WGV opening correction amount calculated based on the supercharging pressure deviation, and the WGV opening is controlled by reflecting the learning value.

  Next, the details of control realized by the ECU 60 will be described in detail. FIG. 5 is a control block diagram showing an outline of a control function by the ECU 60 regarding the supercharging pressure control. In FIG. 5, the calculation function realized by the CPU in the ECU 60 is shown for each block. In the present embodiment, the intake pipe pressure on the downstream side of the throttle is referred to as “supercharging pressure”, and the pressure detected by the intake pressure sensor 17 is assumed to be “actual supercharging pressure PM”.

  In FIG. 5, the target boost pressure calculation unit 61 uses, for example, the map shown in FIG. 6A, and calculates the target boost pressure PMTG using the throttle opening degree TA and the engine rotational speed NE as parameters. . According to the map, a larger value is calculated as the target boost pressure PMTG as the engine speed NE is larger or the throttle opening degree TA is larger.

  The WGV opening correction amount calculation unit 62 calculates a deviation ΔPM between the calculated target boost pressure PMTG and the actual boost pressure PM detected by the intake pressure sensor 17 (ΔPM = PMTG−PM), and is well known. The WGV opening correction amount is calculated using a feedback method. Specifically, the WGV opening correction amount is calculated based on the supercharging pressure deviation ΔPM, for example, using the PID method.

  Further, the base WGV opening calculation unit 63 calculates the base WGV opening by using, for example, the map shown in FIG. 6B and the throttle opening TA and the engine speed NE as parameters. According to the map, a larger value is calculated as the base WGV opening as the engine rotational speed NE is larger or the throttle opening TA is larger. In this case, in particular, the base WGV opening is set within a range of 50 to 80%.

  The learning value calculation unit 64 calculates the WGV fully closed learning value based on the WGV opening correction amount calculated by the WGV opening correction amount calculation unit 62 and updates the learning value. In particular, here, the fully closed learning is performed on the condition that the engine is warmed up at least.

  The target WGV opening calculation unit 65 calculates the target WGV opening based on the base WGV opening, the WGV opening correction amount, and the WGV fully closed learning value (target WGV opening = base WGV opening + WGV opening correction amount + WGV total). Closed learning value).

  The WGV opening control unit 66 calculates a WGV control amount based on the calculated target WGV opening and the actual WGV opening detected by the WGV opening sensor 50. Then, the WGV control amount calculated by the WGV opening calculation unit 66 is output to the drive circuit 67, and the WGV actuator 42 is driven by the drive circuit 67.

  FIG. 7 is a flowchart showing the WGV opening degree control process, and this process is repeatedly executed by the ECU 60 at a predetermined time period.

  In FIG. 7, first, in step S101, parameters (engine speed NE, throttle opening degree TA, actual boost pressure PM) necessary for this processing are read. In step S102, the base WGV opening is calculated with reference to the WGV opening map (for example, FIG. 6B), and in step S103, the target boost pressure map (for example, FIG. 6A) is calculated. The target boost pressure PMTG is calculated with reference to FIG.

  Thereafter, in step S104, a supercharging pressure deviation ΔPM is calculated (ΔPM = PMTG-PM), and in subsequent step S105, a feedback method such as PID is used to calculate a WGV opening correction amount based on the supercharging pressure deviation ΔPM. To do. In step S106, learning of the fully closed position of the wastegate valve 37 is performed. The details will be described later.

  Thereafter, in step S107, the target WGV opening is calculated by adding the base WGV opening, the WGV opening correction amount, and the WGV fully closed learning value (target WGV opening = base WGV opening + WGV opening correction amount + WGV fully closing). Learning value). Finally, in step S108, a WGV control amount is calculated based on the target WGV opening and the actual WGV opening. Then, the drive of the WGV actuator 42 (motor 43) is controlled by the WGV control amount calculated in this way.

  Next, the fully closed learning process (step S106 in FIG. 7) of the waste gate valve 37 will be described with reference to FIG.

  In FIG. 8, first, learning execution conditions are determined in steps S201 to S203. Specifically, in step S201, it is determined whether or not the engine water temperature Tw is equal to or higher than a predetermined determination value Kd (for example, 70 ° C.), that is, whether or not the engine has been warmed up. In step S202, it is determined whether or not the fluctuation amount of the WGV opening accompanying the change with time exceeds a predetermined amount, that is, whether or not the average value of the target WGV opening is out of the predetermined range. In step S203, it is determined whether or not supercharging pressure feedback control is being executed. If any of the above steps S201 to S203 is NO, the process is terminated without executing the subsequent fully closed learning, and if all the steps S201 to S203 are YES, the subsequent fully closed learning (steps S204 to S208) is completed. ).

  In the fully closed learning, the WGV fully closed learning value is updated depending on whether the WGV opening correction amount is shifted to the negative side or the positive side. Actually, in step S204, it is determined whether or not the WGV opening correction amount is less than a predetermined value α1, and in step S205, it is determined whether or not the WGV opening correction amount exceeds a predetermined α2. The determination values α1 and α2 are set to have a relationship of α1 <0 <α2. -Α1 = α2 may be sufficient.

  When the WGV opening correction amount <α1, the process proceeds to step S206, and the predetermined value β is subtracted from the previous value (current memory value) of the WGV fully closed learning value. When WGV opening correction amount> α2, the process proceeds to step S207, and a predetermined value β is added to the previous value (current memory value) of the WGV fully closed learning value. Then, after increasing or decreasing the WGV fully closed learning value as described above, the WGV fully closed learning value in the EEPROM is rewritten with the current value. If the WGV opening correction amount is α1 to α2, the WGV fully closed learning value is not increased or decreased.

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

  Since the WGV fully closed position is learned after the engine 10 is warmed up, the learning error due to the temperature difference in the wastegate valve 37 and its drive system (rod 41 and WGV actuator 42) can be eliminated. As a result, it is possible to correctly learn the WGV fully closed position and thus to properly control the supercharging pressure.

  In addition to the fact that the engine 10 has been warmed up, the supercharging pressure feedback control is being implemented, and the WGV fully closed position is learned on the condition that the fluctuation amount of the WGV opening has exceeded a predetermined amount. Therefore, it is possible to appropriately learn the change of the WGV fully closed position accompanying the change with time.

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

  When the intake pipe pressure is negative, the waste gate valve 37 is controlled to the fully closed position (WGV opening = 0%). In such a configuration, learning of the WGV fully closed position is performed on the condition that the pressure in the intake pipe is negative. When the intake pipe pressure becomes negative (that is, lower than atmospheric pressure), even if the wastegate valve 37 is fully closed, supercharging is not performed, and learning of the WGV fully closed position is possible.

  In addition, the waste gate valve 37 is controlled to the fully closed position (WGV opening = 0%) when the turbine rotational speed is equal to or lower than the predetermined rotational speed (that is, the turbine low rotational state). In such a configuration, learning of the WGV fully closed position is performed on condition that the turbine rotation speed is equal to or lower than the predetermined rotation speed. When the turbine rotation is low, supercharging is not performed even when the wastegate valve 37 is fully closed, and the WGV fully closed position can be learned.

  In the above embodiment, the WGV fully closed learning value is calculated based on the WGV opening correction amount calculated based on the supercharging pressure deviation. Instead, the WGV opening deviation (= target WGV opening−actual WGV). It is also possible to calculate the WGV fully closed learning value based on the WGV opening correction amount calculated based on (opening).

  In the above embodiment, the engine warm-up determination is performed based on whether or not the engine water temperature Tw is equal to or higher than a predetermined warm-up determination value. Instead, the engine oil temperature (the temperature of the engine lubricating oil) is predetermined. The engine warm-up determination may be carried out depending on whether or not the warm-up determination value is equal to or greater than.

  In addition to the wastegate valve, an air bypass valve (ABV) provided in a passage that bypasses the intake compressor may be employed as the flow control valve. That is, as shown in FIG. 9, a bypass passage 71 is provided between an upstream portion and a downstream portion of the intake pipe 11 with the compressor impeller 31 interposed therebetween, and an air bypass valve 72 is provided in the bypass passage 71. It has been. An actuator 74 (ABV actuator) with a motor (electric motor) is connected to the air bypass valve 72 via a rod 73 as a connecting member. By driving the ABV actuator 74, the air bypass valve 72 opens and closes. Accordingly, the opening area of the bypass passage 71, that is, the intake flow rate flowing through the bypass passage 71 is variably adjusted. The ABV actuator 74 is provided with an ABV opening sensor 75 for detecting the ABV opening. The driving of the ABV actuator 74 is controlled by the ECU 60. The configuration of the ABV actuator 74 may be any that conforms to the configuration of the WGV actuator 42, and the description thereof is omitted here (see FIG. 2).

  In this case, the ECU 60 sets the target ABV opening based on the supercharging pressure deviation that is the difference between the target supercharging pressure and the actual supercharging pressure, and makes the actual ABV opening coincide with the target ABV opening. To implement boost pressure feedback control. Then, after the warm-up of the engine 10 is completed, in addition to the fact that the supercharging pressure feedback control is being performed, the average value of the target ABV opening is out of the predetermined range (the fluctuation amount of the ABV opening) The reference position (fully closed position) of the air bypass valve 72 is learned on the condition that the predetermined amount has been exceeded). At this time, the ABV fully closed position is learned from the ABV opening correction amount calculated based on the supercharging pressure deviation.

It is a block diagram which shows the outline of the engine control system in embodiment of invention. It is a figure which shows the mechanical structure of a WGV actuator. It is a figure which shows an equal torque characteristic. It is a PV diagram of an engine. It is a control block diagram which shows the outline | summary of the control function by ECU regarding supercharging pressure control. (A) is a figure which shows a target supercharging pressure map, (b) is a figure which shows a base WGV opening degree map. It is a flowchart which shows a WGV opening degree control process. It is a flowchart which shows a WGV fully closed learning process. It is a block diagram which shows the outline of the engine control system in another form.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Engine, 11 ... Intake pipe, 24 ... Exhaust pipe, 26 ... Water temperature sensor, 30 ... Turbocharger, 31 ... Compressor impeller, 32 ... Turbine wheel, 36 ... Bypass passage, 37 ... Wastegate valve, 41 ... Rod, 42 WGV actuator, 43 ... motor, 60 ... ECU, 71 ... bypass passage, 72 ... air bypass valve, 73 ... rod, 74 ... ABV actuator.

Claims (9)

A flow control valve provided in an internal combustion engine having a turbocharger having an exhaust turbine provided in an exhaust passage and an intake compressor provided in an intake passage, and provided in a passage bypassing the exhaust turbine; or Opening adjustment means for adjusting the opening degree of the flow control valve provided in the passage bypassing the intake compressor based on the reference position of the control valve, and the boost pressure is adjusted by adjusting the opening degree by the opening adjustment means. In the supercharging pressure control device to be controlled,
Reference position learning means for learning a reference position of the flow rate control valve, the reference position learning means learns the reference position after warming up the internal combustion engine ,
A supercharging pressure control means for performing feedback control so as to make the actual supercharging pressure coincide with the target supercharging pressure set according to the operating state of the internal combustion engine;
The supercharging pressure control device for an internal combustion engine, wherein the reference position learning means learns the reference position on condition that feedback control by the supercharging pressure control means is being executed . 2. The internal combustion engine according to claim 1, wherein the reference position learning unit learns the reference position on the condition that an opening fluctuation amount of the flow control valve becomes larger than a predetermined value. Supply pressure control device. A flow control valve provided in an internal combustion engine having a turbocharger having an exhaust turbine provided in an exhaust passage and an intake compressor provided in an intake passage, or provided in a passage bypassing the exhaust turbine; or Opening adjustment means for adjusting the opening degree of the flow control valve provided in the passage bypassing the intake compressor based on the reference position of the control valve, and the boost pressure is adjusted by the opening degree adjustment by the opening adjustment means. In the supercharging pressure control device to be controlled,
Reference position learning means for learning a reference position of the flow rate control valve, the reference position learning means learns the reference position after warming up the internal combustion engine,
The supercharging pressure control device for an internal combustion engine, wherein the reference position learning means learns the reference position on condition that an opening fluctuation amount of the flow control valve becomes larger than a predetermined value . Means for determining whether or not the pressure in the intake passage is negative, and means for controlling the flow control valve to a fully closed position when it is determined that the pressure in the intake passage is negative. Prepared,
4. The internal combustion engine engine according to claim 1, wherein the reference position learning unit learns the reference position on the condition that the pressure in the intake passage is a negative pressure. 5. Supply pressure control device. Means for determining whether or not the rotation of the exhaust turbine is in a predetermined low rotation state, and means for controlling the flow control valve to a fully closed position when it is determined that the rotation is in a low rotation state;
4. The internal combustion engine according to claim 1, wherein the reference position learning means learns the reference position on the condition that the rotation of the exhaust turbine is in a low rotation state. Supply pressure control device. A flow control valve provided in an internal combustion engine having a turbocharger having an exhaust turbine provided in an exhaust passage and an intake compressor provided in an intake passage, or provided in a passage bypassing the exhaust turbine; or Opening adjustment means for adjusting the opening degree of the flow control valve provided in the passage bypassing the intake compressor based on the reference position of the control valve, and the boost pressure is adjusted by adjusting the opening degree by the opening adjustment means. In the supercharging pressure control device to be controlled,
Reference position learning means for learning a reference position of the flow rate control valve, the reference position learning means learns the reference position after warming up the internal combustion engine,
Means for determining whether or not the pressure in the intake passage is negative, and means for controlling the flow control valve to a fully closed position when it is determined that the pressure in the intake passage is negative. Prepared,
The supercharging pressure control device for an internal combustion engine, wherein the reference position learning means learns the reference position on condition that the pressure in the intake passage is negative . A flow control valve provided in an internal combustion engine having a turbocharger having an exhaust turbine provided in an exhaust passage and an intake compressor provided in an intake passage, and provided in a passage bypassing the exhaust turbine; or Opening adjustment means for adjusting the opening degree of the flow control valve provided in the passage bypassing the intake compressor based on the reference position of the control valve, and the boost pressure is adjusted by adjusting the opening degree by the opening adjustment means. In the supercharging pressure control device to be controlled,
Reference position learning means for learning a reference position of the flow rate control valve, the reference position learning means learns the reference position after warming up the internal combustion engine,
Means for determining whether or not the rotation of the exhaust turbine is in a predetermined low rotation state, and means for controlling the flow control valve to a fully closed position when it is determined that the rotation is in a low rotation state;
The supercharging pressure control device for an internal combustion engine, wherein the reference position learning means learns the reference position on condition that the rotation of the exhaust turbine is in a low rotation state . Means for calculating an opening correction amount of the flow control valve based on a target boost pressure set in accordance with an operating state of the internal combustion engine and an actual boost pressure in each case;
The supercharging pressure control device for an internal combustion engine according to any one of claims 1 to 7, wherein the reference position learning means learns the reference position based on the calculated opening correction amount . The boost pressure of the internal combustion engine according to any one of claims 1 to 8, further comprising an electric actuator mechanically connected to the flow control valve via a connecting member and driving the flow control valve using an electric motor as a drive source. Control device.

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