JP2007303330A - Control unit of internal combustion engine with turbocharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control unit of an internal combustion engine with a turbocharger capable of performing deceleration control by efficiently using an auxiliary supercharger, in the internal combustion engine having the auxiliary supercharger for assisting supercharging of the main turbocharger. <P>SOLUTION: In the engine 10 equipped with the turbocharger 30, the auxiliary compressor 38 is provided upstream of a compressor impeller 31. A bypass path 41 bypassing the auxiliary compressor 38 is provided with a bypass valve 42 and the bypass valve 42 is opened and closed by an electric actuator 43. In this arrangement, the engine ECU 60 outputs a control command signal for closing the bypass valve 42 to the electric actuator 43 when deceleration is demanded. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a control device applied to an internal combustion engine including a main supercharger such as a turbocharger and an auxiliary supercharger such as an auxiliary compressor.

  A turbocharger is generally known as a supercharger that supercharges intake air using exhaust power. In recent years, various technical improvements have been attempted in order to improve the responsiveness of supercharging by a supercharger, and an auxiliary compressor has been developed as one of them. Such an auxiliary compressor is provided upstream or downstream of the turbocharger in the intake passage, and is operated by power other than exhaust power. Here, an electric motor is mainly used as a power source other than the exhaust power.

  Moreover, as an engine system provided with an auxiliary compressor, there exists a structure further provided with the bypass path provided so that an auxiliary compressor may be bypassed, and the bypass valve provided in the bypass path (for example, patent document 1). In such a configuration, the opening / closing control of the bypass valve is performed as follows during acceleration. That is, when the auxiliary compressor is driven in a low rotation range, the bypass valve is closed so that the intake air does not flow through the bypass passage, and supercharging assistance is performed by the auxiliary compressor. On the other hand, when the auxiliary compressor is not driven, such as when the supercharging pressure by the turbocharger exceeds the pressure that can be supercharged by the auxiliary compressor, the intake air flows through the bypass path by opening the bypass valve, The auxiliary compressor prevents the intake air flow from being obstructed.

As described above, the prior art such as Patent Document 1 discloses a control method of the bypass valve during acceleration, but does not disclose any control method during deceleration. For this reason, there is room for studying the control of the auxiliary compressor and the bypass valve during deceleration. In Patent Document 1, since the bypass valve is opened when the auxiliary compressor is not driven, the bypass valve remains open during deceleration.
JP 2004-251248 A

  The present invention relates to an internal combustion engine having an auxiliary supercharger that assists supercharging by a main supercharger, and control of an internal combustion engine with a supercharger capable of performing deceleration control by effectively using the auxiliary supercharger. The first object is to provide an apparatus.

  Further, it can be said that the above-described auxiliary supercharger indirectly assists the power of the main supercharger. Therefore, the power assist device is effective in an internal combustion engine equipped with a supercharger that supercharges intake air and the power assist device together with a device that directly assists the power of the supercharger. A second object of the present invention is to provide a control device for an internal combustion engine with a supercharger that can be used for deceleration control.

  Hereinafter, means for solving the above-described problems and the effects thereof will be described.

  The control device for an internal combustion engine with a supercharger according to the present invention presupposes a main supercharger that supercharges intake air by exhaust power, and other than exhaust that is provided upstream or downstream of the main supercharger in the intake passage. The present invention is applied to an internal combustion engine including an auxiliary supercharger that is operated by power and a bypass valve that opens and closes a bypass path that bypasses the auxiliary supercharger. Then, the bypass valve is closed when the auxiliary supercharger is driven, and the open / close state of the bypass valve is controlled so that the bypass path is opened when the auxiliary supercharger is not driven. As a result, supercharging assistance by the auxiliary supercharger is performed when the auxiliary supercharger is driven, and it is avoided that the flow of the intake air is obstructed by the auxiliary supercharger when the auxiliary supercharger is not driven. It has become.

  In the first aspect of the invention, the opening degree of the bypass valve is controlled to the closed side when the deceleration is requested.

  When the opening degree of the bypass valve is controlled to the closed side, the bypass path is closed accordingly, and part or all of the intake air flows through the auxiliary supercharger. Then, since the flow of the intake air is hindered by the auxiliary supercharger, a pressure loss occurs and the pump loss increases. As a result, the engine output is reduced and a larger deceleration is obtained. Therefore, when the deceleration request is made, the bypass valve is controlled to be opened and closed, and the opening degree of the bypass valve is controlled to the closed side, whereby deceleration using the auxiliary supercharger is performed effectively.

  According to the second aspect of the present invention, there is provided means for calculating the degree of the deceleration request, and the opening degree of the bypass valve is adjusted according to the degree of the deceleration request.

  The closer the opening of the bypass valve is to the close side, the greater the amount of intake air that flows through the auxiliary supercharger. As a result, the degree to which the flow of the intake air is hindered increases and the deceleration increases. Therefore, by adjusting the opening degree of the bypass valve, the deceleration according to the degree of the deceleration request can be realized.

  The degree of deceleration request may be calculated based on the amount of change in the accelerator operation amount by the driver, the rate of change over time, and the like. In this case, the greater the amount of change in the accelerator operation amount and the greater the rate of change with time, the more rapid deceleration is required, and the greater the degree of deceleration request. Even when a brake operation is performed, the degree of deceleration request may be calculated to be large, assuming that rapid deceleration is required. In addition, the degree of deceleration request may be calculated based on the target engine output and engine speed.

  In the third aspect of the invention, the bypass valve is fully closed when the degree of deceleration request is greater than or equal to a predetermined value.

  That is, when the bypass valve is fully closed, all the intake air flows through the auxiliary supercharger. In such a case, the pump loss is maximized and the degree of decrease in engine output is maximized. Therefore, according to the said structure, the big deceleration according to the comparatively sudden deceleration request | requirement whose degree of deceleration request | requirement is more than predetermined is implement | achieved.

  In a fourth aspect of the invention, as a premise, a throttle valve for adjusting the intake air amount is provided, and throttle valve opening / closing control for adjusting the opening of the throttle valve is performed. In such a configuration, the opening degree of the bypass valve is controlled to the closed side in cooperation with the throttle valve opening / closing control for adjusting the opening degree of the throttle valve at the time of deceleration request.

  The engine output is actually determined by the amount of air charged into the internal combustion engine in addition to the pressure of the intake air, and the amount of air is adjusted by opening and closing the throttle valve. For this reason, when the deceleration is requested, the desired deceleration can be accurately realized by controlling the opening degree of the bypass valve to the closed side in cooperation with the throttle valve opening / closing control.

  The invention according to claim 5 is applied to an internal combustion engine that uses a turbocharger as a main supercharger and includes a wastegate valve that opens and closes a passage that bypasses a turbine wheel of the turbocharger. The opening of the waste gate valve is controlled to the closed side, and the opening of the waste gate valve is controlled to the open side.

  When the opening degree of the wastegate valve is controlled to the open side, the amount of exhaust gas that flows around the turbine wheel increases. Then, the actual power of the main supercharger operated by the exhaust power is reduced, the supercharging pressure is lowered, and the engine output is reduced. Therefore, it is possible to further increase the deceleration by controlling the opening degree of the bypass valve to the closed side and controlling the opening degree of the waste gate valve to the open side when the deceleration is requested.

  Desirably, the opening degree of the wastegate valve is adjusted according to the degree of deceleration request. As a result, the amount of exhaust gas that flows around the turbine wheel is adjusted, and the actual power of the main supercharger is adjusted, so that a desired deceleration can be realized.

  The invention according to claim 6 is applied to an internal combustion engine that uses a variable nozzle type turbocharger and can adjust the supercharging pressure by operating the variable nozzle, and when the deceleration is requested, the opening of the bypass valve is closed. And the variable nozzle is operated so that the supercharging pressure decreases.

  By operating the variable nozzle of the turbine wheel so that the supercharging pressure decreases, the engine output decreases. Therefore, at the time of deceleration request, it is possible to further increase the deceleration by controlling the opening degree of the bypass valve to the closed side and operating the variable nozzle.

  Desirably, the variable nozzle may be operated according to the degree of deceleration request. Thereby, since the supercharging pressure by the main supercharger is adjusted, a desired deceleration can be realized.

  According to a seventh aspect of the invention, there is provided means for driving and controlling the auxiliary supercharger so that a braking force is generated in the auxiliary supercharger when the deceleration is requested.

  When drive control is performed so that braking force is generated in the auxiliary supercharger, the flow of the intake air is more disturbed than when the auxiliary supercharger idles. For this reason, a larger deceleration can be obtained by performing the drive control so that the braking force is generated in the auxiliary supercharger when the deceleration is requested.

  According to the eighth aspect of the present invention, the auxiliary supercharger is brought into a stationary state or reversely operated so as to generate a braking force in the auxiliary supercharger. According to such a configuration, the degree to which the flow of the intake air is hindered becomes larger than when the auxiliary supercharger idles. For this reason, a larger deceleration can be realized by setting the auxiliary supercharger to a stationary state or reversely operating.

  According to the ninth aspect of the present invention, the torque control for controlling the output torque of the internal combustion engine is performed based on the target torque corresponding to the driver's request, and in the torque control, the auxiliary supercharger is used based on the target torque. The present invention is applied as a control device that performs supercharging assistance and performs opening / closing control of a bypass valve. That is, the present invention is applied as a control device that performs so-called torque-based control for operating various actuators such as an auxiliary supercharger so as to satisfy the target torque.

  In the torque control as in the above configuration, the deceleration according to the target torque corresponding to the driver's request is realized by closing the opening of the bypass valve at the time of the deceleration request.

  In the invention according to claim 10, as a premise, a main supercharger that supercharges intake air by exhaust power, and an upstream or downstream side of the supercharger that is provided in the intake passage and is operated by power other than exhaust. Applies to internal combustion engines with an auxiliary supercharger. In this configuration, the auxiliary supercharger is driven and controlled so that a braking force is generated in the auxiliary supercharger when the deceleration is requested.

  A control method for obtaining a larger deceleration by performing drive control so that braking force is generated in the auxiliary supercharger includes a bypass path that bypasses the auxiliary turbocharger and a bypass valve that opens and closes the bypass path Is not necessarily required. That is, even in an internal combustion engine that does not include a bypass passage and a bypass valve, the braking force is generated in the auxiliary supercharged engine, whereby the flow of intake air is further prevented and a greater deceleration can be obtained.

  In the invention described in claim 11, the auxiliary supercharger is brought into a stationary state or reversely operated so as to generate a braking force in the auxiliary supercharger. According to such a configuration, the degree to which the flow of the intake air is hindered becomes larger than when the auxiliary supercharger idles. For this reason, a larger deceleration can be realized by setting the auxiliary supercharger to a stationary state or reversely operating.

  In the invention described in claim 12, as a premise, a supercharger that supercharges intake air by exhaust power, a power assist device that is operated by power other than exhaust power and directly assists the power of the supercharger, and It is applied to the internal combustion engine provided with. In such a configuration, the power assist device is driven and controlled so that a braking force is generated in the supercharger when a deceleration request is made.

  According to the above configuration, since a braking force is generated in the supercharger, supercharging by the supercharger is suppressed. As a result, the supercharging pressure is reduced, resulting in a reduction in engine output. Therefore, a larger deceleration can be obtained as compared with the case where the drive assist device is not controlled during deceleration.

  By the way, since it can be said that the auxiliary supercharger indirectly assists the power of the supercharger, the present invention is a turbocharger that is operated by exhaust power and supercharges intake air, and other than exhaust power. It is applied to internal combustion engines equipped with a power assist device that is actuated by power and assists the power of the turbocharger directly or indirectly, and realizes a large deceleration by controlling the drive of the power assist device during deceleration. It can be said that there is.

  Further, in an internal combustion engine equipped with an auxiliary supercharger or a power assist device that is operated using a motor generator as a power source, the motor generator may be configured to generate power when a deceleration request is made. According to such a configuration, a braking force is generated in the auxiliary supercharger or the supercharger as a result of power generation, so that there is an advantage that electric energy can be obtained in addition to realizing a large deceleration.

(First embodiment)
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 on-vehicle multi-cylinder gasoline engine that is an internal combustion engine, and the engine of the control system is provided with an electrically assisted turbocharger as a supercharger. . 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 whose opening degree 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 upstream side of the throttle valve 14 is provided with a boost pressure sensor 12 for detecting the pressure upstream of the throttle (a boost pressure by a turbocharger described later), and an intake air temperature sensor 13 for detecting the intake air temperature upstream of the throttle. It has been.

  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.

  A crank angle sensor 26 that outputs a rectangular crank angle signal is attached to the cylinder block of the engine 10 at every predetermined crank angle (for example, at a cycle of 30 ° CA) as the engine 10 rotates.

  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, and these are connected by a shaft 33. 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 shaft 33. The intake air flowing through the intake pipe 11 is compressed by the compressor impeller 31 to perform supercharging. The air supercharged by the turbocharger 30 is cooled by the intercooler 37 and then fed downstream. As the intake air is cooled by the intercooler 37, the charging efficiency of the intake air is increased.

  In the intake pipe 11, an electric auxiliary compressor 38 is provided on the upstream side of the compressor of the turbocharger 30. The auxiliary compressor 38 compresses the intake air upstream from the turbocharger 30. The auxiliary compressor 38 uses a motor 38a as a drive source, and the auxiliary compressor 38 is operated by driving the motor 38a with power supplied from a battery (not shown). That is, unlike the turbocharger 30, the auxiliary compressor 38 uses power other than exhaust as a power source.

  Here, the intake pipe 11 is provided with a bypass passage 41 so as to bypass the auxiliary compressor 38. A bypass valve 42 is provided in the bypass passage 41, and the bypass valve 42 is opened and closed by an electric actuator 43. In this case, by switching the bypass valve 42, it is switched whether the intake air flows through the auxiliary compressor 38 or the bypass passage 41. In the present embodiment, the bypass valve 42 is provided in the bypass passage 41. However, a similar bypass valve may be provided in the intake pipe 11. In short, any configuration that can open and close the bypass passage 41 is acceptable.

  The exhaust pipe 24 is provided with a bypass passage 45 so as to bypass the turbine wheel 32. A waste gate valve (hereinafter referred to as WGV) 46 is provided in the bypass passage 45, and the WGV 46 is opened and closed by an electric actuator 47. In this case, when the WGV 46 is opened, the exhaust power of the turbocharger 30 is reduced and the generation of excessive supercharging pressure is prevented.

  An air cleaner (not shown) is provided at the most upstream portion of the intake pipe 11, and an air flow meter 51 for detecting the intake air amount is provided downstream of the air cleaner. In addition, the present control system is provided with an accelerator opening sensor 53 that detects the depression degree of the accelerator pedal (accelerator opening) and an atmospheric pressure sensor 54 that detects the atmospheric pressure.

  As is well known, the engine ECU (electronic control unit) 60 is mainly composed of a microcomputer composed of a CPU, ROM, RAM, etc., and executes various control programs stored in the ROM, so that the engine operating state in each case. Various controls of the engine 10 are performed according to the above. That is, detection signals are input to the engine ECU 60 from the various sensors described above. The engine 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 driving of the fuel injection valve 19 and the spark plug 25.

  In this embodiment, electronic throttle control by so-called torque base control is performed, and the throttle opening is controlled to a target value based on the torque generated in the engine 10. Briefly, the engine ECU 60 calculates a target torque (requested torque) based on the detection signal of the accelerator opening sensor 53 and calculates a target air amount that satisfies the target torque. The target throttle opening is calculated based on the upstream and downstream pressures and the intake air temperature. The engine ECU 60 controls the throttle actuator 15 with a control command signal based on the target throttle opening, and controls the throttle opening to the target throttle opening.

  The engine ECU 60 determines the control amount of the auxiliary compressor 38 (motor 38a) in conjunction with the torque base control. Thereby, assist power (auxiliary power) is added to the turbocharger 30 during vehicle acceleration so that a desired supercharging pressure can be obtained quickly. That is, the engine ECU 60 calculates target assist power, power assist timing, and the like based on the target boost pressure calculated according to the target torque, and outputs the calculation results to the motor ECU 70. The motor ECU 70 inputs a signal from the engine ECU 60, performs a predetermined calculation process in consideration of the motor efficiency and the like, and controls the power supplied to the motor 38a of the auxiliary compressor 38.

  Further, the engine ECU 60 determines the open / close state of the bypass valve 42 when determining the control amount of the auxiliary compressor 38. Specifically, when the auxiliary compressor 38 is driven, the intake air is supercharged by the auxiliary compressor 38 by closing the bypass valve 42. On the other hand, when the auxiliary compressor 38 is not driven, the bypass valve 42 is opened so that the intake air flows through the bypass passage 41 so that the flow of the intake air is not hindered by the auxiliary compressor 38. To do. The engine ECU 60 controls the electric actuator 43 by a control command signal corresponding to the determined open / close state, and opens / closes the bypass valve 42.

  Now, when the stepping operation is released from the state where the accelerator pedal is depressed, the vehicle is decelerated. At this time, the throttle opening is reduced as the accelerator operation amount decreases, but the response of this deceleration is slow, and there is a case where sufficient deceleration cannot be obtained.

  Therefore, in the present embodiment, when the deceleration is requested due to such a change in the accelerator opening, the bypass valve 42 is fully closed to realize a larger deceleration. That is, when the bypass valve 42 is fully closed, the intake air flows through the auxiliary compressor 38. Then, since the flow of the intake air is hindered by the auxiliary compressor 38, the pump loss increases. As a result, the degree of decrease in output torque is increased, and a greater deceleration is realized.

  The control to fully close the bypass valve 42 at the time of the deceleration request is performed at the time of a relatively sudden deceleration request at which the deceleration obtained by fully closing the throttle valve 14 is not sufficient. In the present embodiment, whether or not the request for deceleration is relatively abrupt is determined based on a change in the accelerator opening. That is, it is assumed that the greater the amount of change in the accelerator opening at the time of deceleration request, the more rapid deceleration is required. Further, when a brake operation is performed by the driver or when an abnormality occurs in the engine 10 and the output torque needs to be reduced, it is determined that the request for deceleration is relatively abrupt.

  Hereinafter, the flow of the torque base control process by the engine ECU 60 and the flow of the determination process of the bypass valve open / close state will be described based on the flowcharts of FIGS. 2 and 3. FIG. 2 is a flowchart showing the base routine. This routine is executed by the engine ECU 60 every 4 msec, for example. In the base routine of FIG. 2, the subroutine of FIG. 3 is appropriately executed.

  In the base routine shown in FIG. 2, first, in step S110, the target torque is calculated by torque base control, and the target throttle opening corresponding to the target torque is calculated. Here, the target torque is calculated according to the driver's request based on the accelerator opening and the like. Subsequently, in step S120, assist power to be applied by the auxiliary compressor 38 is calculated. Specifically, the target power of the turbocharger 30 is calculated according to the target torque, the target throttle opening degree, and the like, the actual power of the turbocharger 30 is calculated, and the difference between the target power and the actual power is set as the assist power. In step S130, the open / close state of the bypass valve 42 is calculated in a bypass valve open / close state determination routine of FIG.

  In the bypass valve open / close state determination routine shown in FIG. 3, first, in step S201, it is determined based on the amount of change in the accelerator opening whether or not it is a relatively sudden deceleration request. When such a deceleration request is made, the open / close state of the bypass valve 42 is fully closed in step S202. On the other hand, when it is not a relatively sudden deceleration request, a normal open / close state determination process is performed in step S203. That is, the open / close state of the bypass valve 42 is determined according to whether the auxiliary compressor 38 is driven or not.

  FIG. 4 is a time chart showing various behaviors when requesting acceleration / deceleration in the present embodiment. In FIG. 4, as a comparison object, conventional control in the case where the bypass valve 42 is opened and closed only according to whether the auxiliary compressor 38 is driven or not is shown, and various behaviors in such control are indicated by broken lines.

  Now, as a relatively sudden deceleration request, when the accelerator opening is greatly reduced as shown in (a) and deceleration is started, the throttle opening is reduced as shown in (b) and as shown in (d). The target torque decreases. And since the comparatively sudden deceleration request | requirement is made, in this Embodiment, the bypass valve 42 will be in a fully-closed state like (c). As a result, as shown in (d), compared to the conventional control with the bypass valve 42 open, the output torque is rapidly reduced in the present embodiment.

  When the accelerator opening increases after deceleration as shown in (a) and acceleration starts, the throttle opening increases as shown in (b) and the target torque increases as shown in (d). Here, in the present embodiment, the bypass valve 42 is fully closed as shown in (c). For this reason, it is not necessary to close the bypass valve 42 after the acceleration is started unlike the conventional control, and the supercharging by the auxiliary compressor 38 is started promptly. As a result, the output torque rises relatively quickly as shown in FIG.

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

  The bypass valve 42 is closed when a deceleration request is made. As a result, the intake air flows through the auxiliary compressor 38 and is blocked by the auxiliary compressor 38. As a result, the pump loss increases and the output torque decreases, so that a larger deceleration can be obtained.

  Here, the bypass valve 42 is fully closed when a relatively sudden deceleration request is made. In this case, all of the intake air flows through the auxiliary compressor 38, and the pump loss is maximized. Therefore, a large deceleration corresponding to a relatively sudden deceleration request is realized.

  Furthermore, there is the following merit when an acceleration request is made after deceleration. That is, since the bypass valve 42 is closed at the time of deceleration, it is not necessary to close the bypass valve 42 with the start of acceleration, and supercharging assistance by the auxiliary compressor 38 is started promptly. As a result, good acceleration response can be obtained.

(Second Embodiment)
In the first embodiment, when a relatively large deceleration request is made, the bypass valve is fully closed to increase the deceleration. However, in this embodiment, the turbocharger is further increased. By operating the WGV as an actuator capable of adjusting the supercharging state, a larger deceleration is realized. Details will be described below. The configuration shown in FIG. 1 is used for the engine control system, and the base routine shown in FIG. 2 is used for the engine ECU 60.

  That is, in this embodiment, when a relatively large deceleration request is made, WGV 46 is fully opened. By opening the WGV 46 in this manner, the amount of exhaust gas flowing to the turbine wheel 32 is reduced. As a result, the actual power of the turbocharger 30 is reduced, the supercharging pressure is reduced, and the output torque is reduced as the supercharging pressure is reduced.

  FIG. 5 is a flowchart showing an open / close state determination routine of the bypass valve 42 and the WGV 46. In the base routine shown in FIG. 2, the routine is executed in place of the bypass valve open / close state determination routine of step S130.

  First, in step S301, it is determined whether or not it is a relatively sudden deceleration request based on the amount of change in the accelerator opening. When such a deceleration request is made, the open / close state of the bypass valve 42 is fully closed in step S302, and the open / close state of the WGV 46 is fully opened in step S303. On the other hand, if it is not a relatively sudden deceleration request, the normal open / close state determination process is performed in steps S304 and S305. That is, in step S304, the open / close state of the bypass valve 42 is determined according to whether the auxiliary compressor 38 is driven or not. In step S305, basically, the open / close state of the WGV 46 is fully closed, while when the supercharging pressure is generated, the open / close state of the WGV 46 is fully opened to reduce the actual power of the turbocharger 30 and perform supercharging. Reduce pressure.

  FIG. 6 is a time chart showing various behaviors when a deceleration request is made in the present embodiment. In FIG. 6, as a comparison object, conventional control in the case where the bypass valve 42 is opened / closed only in accordance with driving / non-driving of the auxiliary compressor 38 is also shown, and various behaviors in such control are indicated by broken lines.

  When the accelerator opening is greatly reduced as shown in (a) and deceleration is started as a relatively steep deceleration request, the throttle opening is reduced as shown in (b) and the target torque as shown in (d). Decrease. Since a relatively sudden deceleration request is made, in this embodiment, the bypass valve 42 is fully closed as shown in (c), and the WGV 46 is fully opened as shown in (e). . As a result, as shown in (d), compared to the conventional control with the bypass valve 42 open, the output torque is rapidly reduced in the present embodiment.

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

  When the deceleration request is relatively sudden, the bypass valve 42 is closed and the WGV 46 is opened. By opening the WGV 46 in this manner, the actual power of the turbocharger 30 is reduced, the supercharging pressure is lowered, and the output torque is lowered, so that a larger deceleration is realized.

(Other embodiments)
In addition, this invention is not limited to the description content of the said embodiment, For example, you may implement like following (1)-(5).

  (1) In the first embodiment, when a relatively large deceleration request is made, the bypass valve 42 is fully closed to increase the deceleration. However, the bypass valve is bypassed according to the degree of the deceleration request. The valve 42 may be closed. That is, the degree of deceleration request is quantified based on the change amount of the accelerator operation amount, and the bypass valve is closed according to the degree of deceleration request.

  In this case, as the bypass valve 42 is closed, the amount of intake air flowing to the auxiliary compressor 38 increases, so that the degree of obstruction by the auxiliary compressor 38 increases. As a result, the degree of decrease in the output torque of the engine 10 increases. Therefore, the desired deceleration can be realized by adjusting the opening degree of the bypass valve 42 according to the degree of the deceleration request.

  FIG. 7 is an example of a map showing the relationship between the degree of deceleration request and the opening of the bypass valve 42 (hereinafter referred to as bypass valve opening). Here, the degree of the deceleration request is obtained based on the change amount of the accelerator opening described above. That is, as shown in FIG. 7, the greater the degree of deceleration request, the better the bypass valve opening is set to the fully closed side. As a result, the greater the degree of deceleration request, the greater the degree to which the flow of intake air is hindered, and the deceleration corresponding to the degree of deceleration request is realized.

  Further, the bypass valve 42 may be closed according to the operating state of the engine 10 without being limited to the degree of deceleration request. That is, when the deceleration request is made, the target supercharging pressure or the like decreases, so the bypass valve 42 may be closed based on the target supercharging pressure. FIG. 8 is an example of a map showing the relationship between the target boost pressure and the bypass valve opening. That is, the bypass valve 42 is preferably closed as the target boost pressure is smaller. As a result, the smaller the target supercharging pressure, the greater the degree to which the flow of intake air is hindered, the actual supercharging pressure is reduced according to the target supercharging pressure, and the deceleration according to the operating state is realized.

  Furthermore, the opening degree of the WGV 46 may be adjusted according to the degree of deceleration request and the operating state of the engine 10. That is, by adjusting the opening degree of the WGV 46, the amount of exhaust gas flowing around the turbine wheel 32 changes, so that the supercharging state by the turbocharger 30 can be adjusted. Therefore, by adjusting the opening degree of the WGV 46, it is possible to adjust the deceleration according to the degree of the deceleration request and the operating state of the engine 10. In an internal combustion engine equipped with a variable nozzle turbo (VNT) capable of adjusting the supercharging state by adjusting the blade angle (nozzle opening) of the turbine wheel 32, the degree of deceleration demand and the engine 10 The blade angle of the turbine wheel may be adjusted according to the operating state. Even in such a configuration, since the output torque of the engine 10 can be adjusted by changing the supercharging state, a desired deceleration can be realized.

  (2) In the above (1), the opening degree of the bypass valve 42 is adjusted in accordance with the degree of deceleration request and the operating state of the engine 10, but the bypass valve 42 is controlled in coordination with the opening / closing control of the throttle valve 14. The opening is adjusted. That is, the output torque of the engine 10 is actually determined by the amount of air charged in the engine 10 and the intake pipe pressure (intake air pressure). For this reason, by adjusting the opening degree of the throttle valve 14 that adjusts the amount of air charged in the engine 10 and the opening degree of the bypass valve 42 that can adjust the intake pipe pressure, that is, in coordination with each other, The desired deceleration can be realized more accurately.

  (3) In the second embodiment, the deceleration is increased by fully closing the opening of the bypass valve and fully opening the opening of the WGV when a relatively sudden deceleration request is made. Not limited to this. In an internal combustion engine equipped with the variable nozzle turbo (VNT) described above, the opening angle of the bypass valve may be fully closed and the blade angle of the turbine wheel may be changed so that the supercharging pressure is reduced. Even in such a configuration, the deceleration can be increased.

  (4) In each of the above embodiments, the bypass valve 42 is closed at the time of a deceleration request. However, the power supplied to the motor 38a is controlled so that a braking force is generated in the auxiliary compressor 38. In this case, the assist power can be calculated as a negative value.

  When the braking force is generated in the auxiliary compressor 38 as described above, the degree to which the flow of the intake air is prevented is increased as compared with the case where the auxiliary compressor 38 is free running. For this reason, the pump loss increases, the degree of decrease in the output torque increases, and a larger deceleration can be obtained.

  Desirably, the supplied power may be controlled so that the auxiliary compressor 38 is in a stationary state or reversely rotated. Thereby, since the flow of the intake air is particularly disturbed, a large deceleration can be realized.

  Further, the auxiliary compressor 38 using a motor generator as a power source instead of the motor 38a may be configured to cause the motor generator to generate power when a deceleration request is made. According to such a configuration, a braking force is generated in the auxiliary compressor 38 along with power generation, so that a large deceleration is realized. In this case, there is an advantage that electric energy can be obtained.

  (5) The configuration in which the braking force is generated in the auxiliary compressor 38 when the deceleration request is made as in the above (4) is also effective in an engine system that does not include the bypass passage 41 and the bypass valve 42. In such an engine system as well, by controlling the power supplied to the motor 38a so that a braking force is generated in the auxiliary compressor 38, the flow of the intake air is hindered and a large deceleration can be obtained.

  Furthermore, in an engine system that does not include the bypass passage 41 and the bypass valve 42, a motor is attached to the shaft 33 of the turbocharger 30 instead of the auxiliary compressor 38, and an electric turbocharger that directly assists the power of the turbocharger 30 is provided. To do. In such an engine system, when a deceleration request is made, the motor is driven and controlled so that a braking force is generated in the motor. When braking force is generated by the motor in such an engine system, the actual power of the turbocharger 30 is reduced and the supercharging pressure is lowered. As a result, the output torque of the engine 10 decreases, and a large deceleration can be obtained.

  In short, in an engine system equipped with a power assist device that assists the power of the supercharger directly or indirectly, by driving and controlling the power assist device so as to assist the turbocharger with negative power when a deceleration request is made. It is possible to realize a large deceleration.

  In particular, in an internal combustion engine including a power assist device that is operated using a motor generator as a power source, the motor generator may be configured to generate power when a deceleration request is made. According to this configuration, negative power is assisted by the supercharger as the power is generated. In this case, there is an advantage that a large deceleration is realized and electric energy can be obtained.

It is a block diagram which shows the outline of the engine control system in embodiment of invention. It is a flowchart which shows the base routine by engine ECU. It is a flowchart which shows a bypass valve opening / closing state determination routine. It is a time chart which shows the various behavior at the time of the acceleration / deceleration request | requirement. It is a flowchart which shows the opening / closing state determination routine of a bypass valve and WGV. It is a time chart which shows the various behavior at the time of the deceleration request | requirement in 2nd Embodiment. It is a figure which shows the relationship between the degree of a deceleration request | requirement, and a bypass valve opening degree. It is a figure which shows the relationship between a target supercharging pressure and a bypass valve opening degree.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Engine, 30 ... Turbocharger as main supercharger, 38 ... Auxiliary compressor as auxiliary supercharger, 41 ... Bypass passage, 42 ... Bypass valve, 43 ... Electric actuator, 45 ... Bypass passage, 46 ... WGV, 47: Electric actuator, 60: Engine ECU.

Claims (12)

A main supercharger that supercharges intake air by exhaust power; an auxiliary supercharger that is provided upstream or downstream of the supercharger in the intake passage and that is operated by power other than exhaust; and the auxiliary supercharger Applied to an internal combustion engine provided with a bypass valve that opens and closes a bypass path provided around
In the control device for controlling the open / close state of the bypass valve so as to open the bypass valve when the auxiliary supercharger is not driven while closing the bypass valve when the auxiliary supercharger is driven,
A control device for an internal combustion engine with a supercharger, comprising a deceleration time control means for controlling the opening degree of the bypass valve to a closed side when a deceleration request is made.   The turbocharger according to claim 1, further comprising means for calculating a degree of deceleration request, wherein the deceleration time control means adjusts an opening of the bypass valve in accordance with the degree of deceleration request. Control device for internal combustion engine.   3. The control device for an internal combustion engine with a supercharger according to claim 2, wherein the deceleration control means fully closes the bypass valve when the degree of deceleration request is equal to or greater than a predetermined value. In a control device for an internal combustion engine having a throttle valve for adjusting the amount of intake air, and performing throttle valve opening / closing control for adjusting the opening of the throttle valve,
The internal combustion engine with a supercharger according to any one of claims 1 to 3, wherein the deceleration time control means controls the opening degree of the bypass valve to the closed side in cooperation with the throttle valve opening / closing control. Control device. The turbocharger is used as the main supercharger, and is applied to an internal combustion engine including a wastegate valve that opens and closes a passage provided around the turbine wheel of the turbocharger.
The said deceleration time control means controls the opening degree of the said bypass valve to a close side, and controls the opening degree of the said wastegate valve to an open side. Control device for an internal combustion engine with a supercharger. A variable nozzle turbocharger is used as the main supercharger, and is applied to an internal combustion engine capable of adjusting a supercharging pressure by operating a variable nozzle of the variable nozzle turbocharger.
6. The deceleration control means controls the opening degree of the bypass valve to a closed side and operates the variable nozzle so that the supercharging pressure decreases. The control apparatus of the internal combustion engine with a supercharger of description.   2. The deceleration control means controls the opening degree of the bypass valve to a closed side and drives and controls the auxiliary supercharger so that a braking force is generated in the auxiliary supercharger. 6. The control apparatus for an internal combustion engine with a supercharger according to any one of 6 above.   8. The internal combustion engine with a supercharger according to claim 7, wherein the deceleration control means causes the auxiliary supercharger to be stationary or reversely operated so as to generate a braking force on the auxiliary supercharger. Engine control device.   Torque control is performed to control the output torque of the internal combustion engine based on the target torque corresponding to the driver's request, and during the torque control, drive control of the auxiliary supercharger is performed based on the target torque. The control device for an internal combustion engine with a supercharger according to any one of claims 1 to 8, wherein the control device is applied as a control device that performs opening / closing control of the bypass valve. Applicable to an internal combustion engine equipped with a main supercharger that supercharges intake air by exhaust power and an auxiliary supercharger that is provided upstream or downstream of the supercharger in the intake passage and is operated by power other than exhaust A control device,
A control device for an internal combustion engine with a supercharger, comprising: an auxiliary supercharger control means for driving and controlling the auxiliary supercharger so that a braking force is generated in the auxiliary supercharger when a deceleration request is made.   The supercharger according to claim 10, wherein the auxiliary supercharger control means causes the auxiliary supercharger to perform a stationary operation or a reverse operation so as to generate a braking force on the auxiliary supercharger. Control device for internal combustion engine. A control device applied to an internal combustion engine comprising a supercharger that supercharges intake air by exhaust power and a power assist device that is operated by power other than exhaust and directly assists the power of the supercharger. There,
A control device for an internal combustion engine with a supercharger, comprising means for driving and controlling the power assist device so that a braking force is generated in the supercharger when a deceleration request is made.

Images