JP2017089583A - Control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of an internal combustion engine which can suppress the chattering of a waste gate valve.SOLUTION: A control device of an internal combustion engine comprises: a waste gate valve which adjusts a flow rate of exhaust emission flowing in an exhaust bypass passage which bypasses a turbine of a supercharger; an actuator for switch-driving the waste gate valve; and a control part for adjusting an opening of the waste gate valve by controlling the actuator. When boost pressure reaches target boost pressure before the waste gate valve is fully closed, and when the boost pressure is in hunting, the control part performs full-close control for fully closing the waste gate valve.SELECTED DRAWING: Figure 4

Description

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

  An exhaust turbine driven supercharger is known. Further, as shown in Patent Document 1, there is also known a supercharger equipped with an exhaust bypass passage that bypasses the exhaust turbine and a waste gate valve that adjusts the flow rate of exhaust gas flowing through the exhaust bypass passage by an opening / closing operation. The supercharging pressure can be adjusted by allowing a part of the exhaust to flow through the exhaust bypass passage. For example, when the opening degree of the waste gate valve is reduced, the flow rate of the exhaust gas flowing through the exhaust bypass passage is reduced, and the supercharging pressure is increased. When the waste gate valve is fully closed, the exhaust gas does not flow through the exhaust bypass passage, and the boost pressure further increases.

  However, the position of the seating portion of the waste gate valve may slightly change due to wear over time. In this case, the waste gate valve cannot be fully closed, and there is a possibility that sufficient supercharging pressure cannot be obtained. Patent Document 2 discloses a configuration that reliably closes the waste gate valve in such a case. Specifically, if the actual opening of the waste gate valve is smaller than a predetermined opening near the fully closed state, the opening adjustment by the opening adjustment unit is canceled and the waste gate valve is seated on the seating part. A configuration is disclosed in which full-closed control is performed to close the waste gate valve with a predetermined operation amount.

Japanese Patent Laying-Open No. 2015-81578 Japanese Patent Laying-Open No. 2015-40488

  By the way, even at the time of full throttle in which the intake throttle valve is fully opened and accelerated, full-close control is performed to close the waste gate valve. Here, if the supercharging pressure reaches the target supercharging pressure before the waste gate valve is fully closed, the waste gate valve may be held in a slightly opened state and may not be completely closed. If exhaust pulsation acts on the waste gate valve in this state, the waste gate valve causes chattering (fluttering), and a hitting sound may occur due to contact with the seating portion of the waste gate valve.

  An object of the present invention is to provide a control device for an internal combustion engine that can suppress chattering of a waste gate valve.

  An internal combustion engine control apparatus according to the present invention includes a waste gate valve that adjusts a flow rate of exhaust gas that flows through an exhaust bypass passage that bypasses a turbine of a supercharger, an actuator that opens and closes the waste gate valve, and controls the actuator And a control unit that adjusts the opening of the waste gate valve, and the control unit is a case where a supercharging pressure reaches a target supercharging pressure before the waste gate valve is fully closed, When the supercharging pressure is hunting, full-closed control for closing the waste gate valve is executed.

  According to this configuration, when the supercharging pressure reaches the target supercharging pressure before the waste gate valve is fully closed and the supercharging pressure is hunting, the control unit performs full close control for closing the waste gate valve. Run. Thereby, even if exhaust pulsation acts on the waste gate valve in a state where the waste gate valve is slightly opened, chattering of the waste gate valve is suppressed.

  According to the present invention, chattering of the waste gate valve can be suppressed.

It is a figure explaining an example of the control apparatus of an internal combustion engine. It is a figure for demonstrating an example of the state in which the waste gate valve opened slightly. It is a figure for demonstrating an example of a waste gate valve. It is a flowchart which shows an example of operation | movement of ECU. It is an example of the graph showing the relationship between clearance and valve opening. It is an example of the graph showing the relationship between elapsed time and an actual supercharging pressure.

  Hereinafter, an embodiment for carrying out this case will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating an example of a control device for the internal combustion engine 10. FIG. 2 is a view for explaining an example of a state in which the waste gate valve 27 is slightly opened. FIG. 3 is a view for explaining an example of the waste gate valve 27. First, as shown in FIG. 1, the supercharger 20 includes an intake air compressor 21 provided in the intake passage 11 of the internal combustion engine 10 and an exhaust turbine 22 provided in the exhaust passage 12. The intake compressor 21 includes a compressor impeller 23 therein. The exhaust turbine 22 includes a turbine wheel 24 therein. The compressor impeller 23 and the turbine wheel 24 are connected via a shaft 25 so as to be integrally rotatable. In the supercharger 20, when the exhaust of the internal combustion engine 10 is blown onto the turbine wheel 24, the turbine wheel 24 and the compressor impeller 23 rotate integrally. As a result, the intake air flowing through the intake passage 11 is pressurized and forced into the combustion chamber of the internal combustion engine 10.

  The exhaust turbine 22 is provided with an exhaust bypass passage 26 having a shape extending so as to bypass (bypass) the turbine wheel 24. The exhaust bypass passage 26 extends in such a shape that a portion on the exhaust upstream side of the turbine wheel 24 in the exhaust passage 12 communicates with a portion on the exhaust downstream side. The exhaust turbine 22 is provided with a waste gate valve 27 that switches between communication through the exhaust bypass passage 26 and blocking of the communication and adjusts the flow rate of the exhaust gas flowing through the exhaust bypass passage 26.

  As shown in FIG. 2, the exhaust bypass passage 26 includes a communication passage 32 and a through hole 33. The communication passage 32 is formed in a shape that communicates with a portion of the exhaust passage 12 on the exhaust downstream side of the turbine wheel 24. The through-hole 33 is formed in a shape that communicates a portion of the exhaust passage 12 upstream of the turbine wheel 24 with respect to the exhaust passage 12 and the communication passage 32.

  As shown in FIGS. 1 to 3, the waste gate valve 27 has a seating portion (hereinafter, referred to as a valve seating portion) 41 at the peripheral edge of the through hole 33 on the side of the communication path 32. As shown in FIG. 1, the waste gate valve 27 includes a valve body 46 connected to an electric actuator 44 through a link mechanism 42. The link mechanism 42 includes a swing arm 43 that swings about the axis of the rotary shaft 36 as a swing center. A drive rod 45 of an actuator 44 is connected to one end of the swing arm 43 so as to be relatively rotatable. As shown in FIGS. 2 and 3, a valve body 46 formed in a disc shape is integrally attached to the other end of the swing arm 43 by a connecting pin 46A.

  The internal combustion engine 10 and the supercharger 20 are provided with various sensors as peripheral devices. Examples of the sensors include an engine speed sensor 51A, a throttle opening sensor 51B, a WGV opening sensor 51C, an engine torque sensor 51D, a vehicle speed sensor 51E, and a supercharging pressure sensor 51F.

  The engine speed sensor 51 </ b> A outputs a detection signal corresponding to the speed of the internal combustion engine 10. The throttle opening sensor 51B outputs a detection signal corresponding to the opening of the intake throttle valve 11A. As shown in FIG. 1, the intake throttle valve 11 </ b> A is arranged in the intake upstream side of the compressor impeller 23 in the intake passage 11. The WGV opening sensor 51C outputs a detection signal corresponding to the opening of the waste gate valve 27. The engine torque sensor 51D outputs a detection signal corresponding to the output (torque) of the internal combustion engine 10. The vehicle speed sensor 51E outputs a detection signal corresponding to the speed of the vehicle. The supercharging pressure sensor 51F outputs a detection signal corresponding to the actual supercharging pressure that is the actual pressure of the gas in the intake passage 11. The supercharging pressure sensor 51F is disposed in the intake passage 11 on the downstream side of the supercharger 20 (specifically, the compressor impeller 23).

  An ECU (Engine Control Unit) 50 made up of a microcomputer or the like is also provided as a peripheral device. The ECU 50 takes in detection signals output from the various sensors described above, and performs various calculations based on the detection signals. Then, the ECU 50 executes various controls related to the operation of the internal combustion engine 10 such as operation control of the actuator 44 based on the calculation result. The control device for the internal combustion engine 10 according to the present embodiment includes the waste gate valve 27, the actuator 44, the ECU 50, and the like.

  In addition, an operation switch 52 and a relay 53 are also provided as the peripheral devices described above. The operation switch 52 is turned on when the operation of the internal combustion engine 10 is started, and is turned off when the operation of the internal combustion engine 10 is stopped. The relay 53 includes an actuator 44, an ECU 50, an engine speed sensor 51A, a throttle opening sensor 51B, a WGV opening sensor 51C, an engine torque sensor over a predetermined period after the operation of the internal combustion engine 10 is stopped by turning off the operation switch 52. The power supply to 51D, the vehicle speed sensor 51E, and the supercharging pressure sensor 51F is continued.

  In the operation control of the actuator 44, the operation position of the swing arm 43 is changed according to the operating state of the internal combustion engine 10, as indicated by the solid arrow in FIG. Through the operation control of the actuator 44, when the valve body 46 reaches the position where the valve seat 46 is seated on the valve seat 41 (position shown in FIG. 1 [fully closed position]), the through-hole 33 is closed. It will be in the closed state (valve closed state). On the other hand, when the valve body 46 is separated from the valve seat 41 (valve open position), the through-hole 33 is opened, so that the exhaust bypass passage 26 is opened (valve open state).

  Next, the operation of the ECU 50 will be described with reference to FIGS.

  FIG. 4 is a flowchart showing an example of the operation of the ECU 50. FIG. 5 is an example of a graph showing the relationship between the clearance and the valve opening. FIG. 6 is an example of a graph showing the relationship between elapsed time and actual supercharging pressure. The flowchart shown in FIG. 4 is repeatedly executed with an extremely short cycle time of, for example, about several microseconds to several tens of microseconds. The flowchart shown in FIG. 4 is executed alone or in parallel with other flowcharts.

  First, as shown in FIG. 4, the ECU 50 acquires the engine speed, throttle opening, waste gate valve (indicated as WGV in FIG. 4) opening, engine torque, vehicle speed, and actual supercharging pressure based on the accelerator operation. (Step S101). More specifically, the ECU 50 acquires the detection signal output from the engine speed sensor 51A as the engine speed. Similarly, the ECU 50 detects the detection signals output from the throttle opening sensor 51B, the WGV opening sensor 51C, the engine torque sensor 51D, the vehicle speed sensor 51E, and the supercharging pressure sensor 51F, respectively. Obtained as the degree, engine torque, vehicle speed, and actual boost pressure.

  When the process of step S101 is completed, the ECU 50 then determines whether or not the actual boost pressure has reached the target boost pressure (step S102). More specifically, the ECU 50 sequentially determines a target boost pressure, which is a target value of the boost pressure, based on the following vehicle state represented by vehicle speed and the like. Here, the vehicle state is a general term for the traveling state and load state of the vehicle. The driving state and the load state are not strictly distinguished from each other, and both the driving state and the load state are, for example, part of parameters such as engine speed, throttle opening, engine torque, vehicle speed, and actual boost pressure. Or they are all represented. Then, the ECU 50 determines whether or not the actual boost pressure has reached the determined target boost pressure.

  Here, when the ECU 50 determines that the actual boost pressure has not reached the target boost pressure (step S102: NO), this flowchart is ended. In this case, the waste gate valve 27 is not held in a slightly opened state. Therefore, no hitting sound is generated and no special control is required. On the other hand, when the ECU 50 determines that the actual boost pressure has reached the target boost pressure (step S102: YES), the ECU 50 then determines whether or not the WGV opening is within a threshold (step S103). Specifically, when the ECU 50 determines that the waste gate valve 27 is held in a slightly opened state (see FIG. 2), the WGV opening is within the range of the opening that contacts the valve seat 41. Judge whether or not.

  Here, as shown in FIG. 5, there is a predetermined relationship between the clearance and the valve opening. The clearance represents a gap formed between the valve seat 41 and the waste gate valve 27 (more specifically, the valve body 46). As shown in FIG. 5, when the clearance between the valve seat 41 and the waste gate valve 27 is equal to or less than a predetermined value, in other words, when the WGV opening is within a threshold corresponding to the predetermined value, the waste gate valve 27 comes into contact with the valve seat 41 and a hitting sound is generated. The predetermined value is smaller than the clearance corresponding to the slightly opened state shown in FIG.

  Further, when the ECU 50 determines that the WGV opening is not within the threshold (step S103: NO), the ECU 50 determines whether or not the actual supercharging pressure is hunting (step S104). More specifically, as shown in FIG. 6, when the actual boost pressure varies with a constant fluctuation amount over a predetermined period, the ECU 50 determines that the actual boost pressure is hunting. Judge that the boost pressure is not hunting. That is, when the waste gate valve 27 chatters, the exhaust gas does not flow stably in the exhaust bypass passage 26, and the exhaust gas blown to the turbine wheel 24 also becomes unstable. Thereby, the rotation of the compressor impeller 23 that rotates integrally with the turbine wheel 24 also becomes unstable, and the actual supercharging pressure varies. If the ECU 50 determines that the actual supercharging pressure is not hunting (step S104: NO), the ECU 50 ends this flowchart. On the other hand, when the actual supercharging pressure is hunted, a hitting sound is generated. That is, even if a clearance larger than the predetermined value described above exists between the valve seat 41 and the waste gate valve 27, the clearance is equal to or less than the clearance corresponding to the slightly opened state shown in FIG. If hunting occurs, the waste gate valve 27 contacts the valve seat 41. In other words, even if the WGV opening is larger than the above-described threshold, the waste gate is less than the opening corresponding to the slightly opened state shown in FIG. The valve 27 contacts the valve seat 41. In this case, a hitting sound is generated.

  Therefore, the ECU 50 determines that the WGV opening is within the threshold value in the process of step S103 (step S103: YES), or determines that the actual boost pressure is hunting in the process of step S104 ( Step S104: YES), the fully closed control for completely closing the waste gate valve 27 is executed (step S105). Thereby, chattering of the waste gate valve 27 is suppressed, and the hitting sound is reduced. In particular, in order to obtain high evaluation when measuring noise outside the vehicle, it is not necessary to separately provide a cover member for suppressing the hitting sound in the supercharger 20, and an increase in vehicle cost can be suppressed.

  When the process of step S105 is completed, the routine shifts to a normal operation without hitting sound, but the actual supercharging pressure increases and deviates from the target supercharging pressure. Therefore, the ECU 50 controls the intake throttle valve 11A to the closed side (step S106). This converges to the target boost pressure. When the process of step S106 ends, the ECU 50 ends this flowchart.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

DESCRIPTION OF SYMBOLS 10 Internal combustion engine 20 Supercharger 27 Waste gate valve 41 Valve seating part 44 Actuator 46 Valve body 50 ECU

Claims (1)

A waste gate valve that adjusts the flow rate of the exhaust gas flowing through the exhaust bypass passage that bypasses the turbocharger turbine;
An actuator for opening and closing the waste gate valve;
A controller that controls the actuator to adjust the opening of the waste gate valve, and
The control unit is a case where a supercharging pressure reaches a target supercharging pressure before the wastegate valve is closed, and when the supercharging pressure is hunting, the control unit completely closes the wastegate valve. A control device for an internal combustion engine, characterized by executing a closing control.

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