JP2015059568A - Control device of engine with supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of an engine with a supercharger capable of preventing EGR gas from stagnating inside an intake bypass valve and preventing condensate water from being generated inside the same.SOLUTION: A control device of an engine with a supercharger comprises the supercharger 7, an exhaust recirculation passage 17, an exhaust recirculation valve 18, an intake air bypass passage 41, an ABV 42 and an ECU 50. The control device of the engine with the supercharger also has scavenging means 89, 44 and 43 which scavenges a pressure equilibrium chamber 82 to discharge recirculated exhaust gas stagnating in the pressure equilibrium chamber 82 of the ABV valve 42.

Description

  The present invention relates to an engine provided with a supercharger, and relates to a control device for a supercharged engine that controls various devices provided in the supercharger and the engine.

  Conventionally, it is well known that an exhaust gas recirculation (EGR) device is also provided in an engine equipped with a supercharger. The following Patent Document 1 describes an engine equipped with this type of supercharger and a low-pressure loop EGR device provided on the engine. The supercharger includes a turbine provided in the exhaust passage and a compressor provided in the intake passage and driven by the turbine. In the EGR device, an EGR passage is provided between an exhaust passage downstream of the turbine and an intake passage upstream of the compressor, and an EGR valve is provided in the EGR passage. In this EGR device, the EGR gas recirculation amount is limited by closing the EGR valve as necessary in order to prevent corrosion due to condensed water generated in the EGR passage while responding to strict NOx reduction requirements. It is like that.

  Here, in a turbocharged engine, if the pressure difference between the inlet and outlet of the compressor of the turbocharger becomes too large, the air flow becomes unstable on the blade surface of the compressor, and self-excited vibration occurs in the air flow. Surging may occur. Therefore, in order to prevent this surging, an intake bypass passage that bypasses between the intake passage upstream of the compressor and the intake passage downstream of the compressor is provided, and an intake bypass valve is provided in the intake bypass passage. Open the valve if necessary. This reduces the pressure difference between the compressor inlet and outlet and prevents surging. Further, it is conceivable to provide a low-pressure loop EGR device in a supercharged engine equipped with this type of intake bypass valve.

  This type of intake bypass valve is disclosed in Patent Document 2 below. The intake bypass valve includes a movable body having a valve member that opens and closes a valve seat provided between the inflow path and the outflow path of the intake bypass path on the outflow path side, and an elastic member that biases the movable body in the closing direction. , An electromagnetic device that moves the movable body in the opening direction by electromagnetic force against the biasing force of the elastic member, and a pressure that is provided between the stationary member of the electromagnetic device and the movable body and is partitioned with respect to the outflow path In a closed state in which the valve member is seated on the valve seat, the pressure responsive member forming the equilibrium chamber and the pressure introduction passage formed in the movable body and communicating with the inlet passage and the pressure equilibrium chamber are provided. The air pressure applied to the road side and the pressure equilibrium chamber side is balanced. The pressure introduction passage is provided with a dynamic pressure reducing member that reduces the dynamic pressure of air acting on the pressure equilibrium chamber. With this configuration, the dynamic pressure reducing member provided in the pressure introduction passage reduces the dynamic pressure of air acting on the pressure equilibrium chamber at the start of the valve opening, shortens the valve opening time, and improves the valve opening response. be able to.

JP 2012-229679 A JP 2013-83339 A

  However, in an engine with a supercharger equipped with a low-pressure loop type EGR device, when an intake bypass valve is provided in the intake bypass passage as described above, if EGR is introduced in the supercharge region (intake bypass valve: closed valve) Due to the pressure change (low-high) at the compressor outlet, the EGR gas flows into the pressure equilibrium chamber of the intake bypass valve, and the inflowed EGR gas may remain in the pressure equilibrium chamber. As described above, when the EGR gas remaining in the intake bypass valve is cooled after the engine is stopped, condensed water may be generated due to moisture in the EGR gas. For this reason, the condensed water may corrode the driving unit inside the intake bypass valve or may freeze the condensed water to fix the driving unit, thereby hindering normal operation of the intake bypass valve.

  The present invention has been made in view of the above circumstances, and its object is to prevent EGR gas from staying inside the intake bypass valve and to prevent the generation of condensed water inside the intake bypass valve. An object of the present invention is to provide a supercharger-equipped engine control device.

In order to solve the above-described problems, a supercharger-equipped engine control device of the present invention has the following configuration.
(1) A supercharger that is provided between an intake passage and an exhaust passage of an engine and boosts the intake air in the intake passage, and the supercharger is disposed in a compressor disposed in the intake passage and in the exhaust passage. And a rotating shaft that connects the compressor and the turbine so as to be integrally rotatable, and a portion of the exhaust discharged from the combustion chamber of the engine to the exhaust passage flows into the intake passage as exhaust recirculation gas. The exhaust gas recirculation passage, the exhaust gas recirculation valve for adjusting the flow of the exhaust gas recirculation gas in the exhaust gas recirculation passage, the exhaust gas recirculation passage, the inlet of which is connected to the exhaust gas passage downstream from the turbine, and the outlet of the exhaust gas recirculation passage An intake bypass passage that bypasses the connection between the intake passage upstream of the compressor and the intake passage upstream of the compressor. An intake bypass valve for opening and closing the intake bypass passage, the intake bypass valve includes a valve seat provided on the intake bypass passage, a movable body having a valve member provided so as to be seatable on the valve seat, and movable A driving means for driving the body, a pressure equilibrium chamber provided and partitioned between the driving means and the movable body, and a pressure introduction path formed in the movable body for communicating the intake bypass passage and the pressure equilibrium chamber. A supercharger-equipped engine comprising: an operating state detecting unit for detecting an operating state of the engine; and a control unit for controlling at least the exhaust gas recirculation valve and the intake bypass valve based on the detected operating state The apparatus is characterized in that scavenging means for scavenging the pressure equilibrium chamber is provided in order to discharge the exhaust gas recirculation gas remaining in the pressure equilibrium chamber of the intake bypass valve.

(2) In the control apparatus for an engine with a supercharger described in (1), the scavenging means includes a scavenging flow path provided in the intake bypass valve and communicating with the pressure equilibrium chamber. (3) In the control device for an engine with a supercharger described in (1), the scavenging means is provided in the intake bypass valve, and a scavenging passage communicating with the pressure equilibrium chamber and one end of the scavenging passage are connected to the scavenging passage. A communication passage communicating with the intake passage upstream of the compressor and the scavenging passage or the communication passage are provided to block the flow of gas from the scavenging passage to the communication passage, and from the communication passage toward the scavenging passage. A non-supercharging region in which the supercharger does not operate, and the control means is configured to scavenge the exhaust gas recirculation gas remaining in the pressure equilibrium chamber. During the valve closing control, the intake bypass valve is repeatedly opened and closed.
(4) In the control device for an engine with a supercharger described in (3), the control means repeatedly opens and closes the intake bypass valve when the engine is stopped.

(5) In the control device for an engine with a supercharger described in (1), the intake passage is provided with an intake air amount adjustment valve for adjusting an intake air amount flowing through the intake passage, and the scavenging means is configured to A scavenging passage that is provided in the bypass valve and communicates with the pressure balancing chamber, a communication passage that communicates one end of the scavenging passage with the intake passage downstream of the intake amount adjustment valve, and provided in the scavenging passage or the communication passage. And a check valve that allows a gas flow from the scavenging passage to the communication passage and prevents a gas flow from the communication passage to the scavenging passage, and that exhausts recirculation gas remaining in the pressure equilibrium chamber When the engine is operated at a light load when the intake air amount adjustment valve is closed, negative pressure generated in the intake passage downstream of the intake air amount adjustment valve is passed through the communication passage and the scavenging passage. Said Characterized in that the action of the force balance chamber.

(6) In the control device for an engine with a supercharger described in (1), an intake air amount adjusting valve for adjusting an intake air amount flowing through the intake air passage is provided in the intake air passage, and the scavenging means A scavenging passage that is provided in the bypass valve and communicates with the pressure equilibrium chamber, and a communication passage that communicates one end of the scavenging passage with the intake passage downstream of the intake air amount adjustment valve, and remains in the pressure equilibrium chamber In order to scavenge the exhaust gas recirculation gas, during the light load operation of the engine in which the intake air amount adjustment valve is closed, a negative pressure generated in the intake passage downstream of the intake air amount adjustment valve is generated in the communication passage and the scavenging air. The pressure balance chamber is caused to act through a passage.
(7) In the control device for an engine with a supercharger described in (5) or (6), a throttle is provided in the communication path.
(8) In the control device for an engine with a supercharger described in any one of (5) to (7), when an open / close valve is provided in the communication passage, and the control means controls the exhaust recirculation valve to be closed. The exhaust gas recirculation gas remaining in the pressure equilibrium chamber is scavenged.

(9) In the supercharger-equipped engine control device according to (1), a scavenging passage communicating with the pressure equilibrium chamber, and a communication passage communicating one end of the scavenging passage with the intake passage upstream of the compressor A pressure pump is provided in the communication passage, and the control means controls the pressure from the pressure pump through the communication passage and the scavenging passage when the exhaust gas recirculation valve is closed. By supplying to the equilibrium chamber, the exhaust gas recirculation gas remaining in the pressure equilibrium chamber is pushed out and discharged.
(10) In the control device for an engine with a supercharger described in (1), a scavenging passage that communicates with the pressure equilibrium chamber, and a communication passage that communicates one end of the scavenging passage with the intake passage upstream of the compressor. A negative pressure pump is provided in the communication passage, and the control means controls the pressure balancing chamber from the negative pressure pump through the communication passage and the scavenging passage when the exhaust gas recirculation valve is controlled to be closed. The exhaust gas recirculation gas remaining in the pressure equilibrium chamber is sucked and discharged by sucking a gas from the pressure balance chamber.
(11) In the control device for an engine with a supercharger described in (1), the scavenging means repeatedly opens and closes the intake bypass valve according to an EGR amount when the exhaust recirculation valve is controlled to close. It is characterized by controlling.
(12) In the control device for an engine with a supercharger described in (11), the amount of EGR gas remaining in the intake bypass valve is estimated from the operating state of the engine, and the estimated amount of RGR gas is calculated. Accordingly, the number of counts for repeatedly opening and closing the intake bypass valve is determined.
(13) In the control device for an engine with a supercharger described in (12), the count number is increased under a process condition that changes from non-supercharging to supercharging and an engine stop condition.

According to the invention of (1), there is provided scavenging means for scavenging the pressure equilibrium chamber in order to exhaust the exhaust gas recirculation gas remaining in the pressure equilibrium chamber of the intake bypass valve. The EGR gas remaining in the exhaust gas can be reliably removed, so that even if the engine is cooled after the engine is stopped, the condensed water is not generated by the moisture in the EGR gas. There is no possibility that the drive unit is corroded or the drive unit is fixed by freezing of condensed water, thereby hindering normal operation of the intake bypass valve.

According to the invention of (2), the scavenging means includes a scavenging flow path provided in the intake bypass valve and communicating with the pressure equilibrium chamber, so that air is circulated through the scavenging flow path. Thus, the EGR gas remaining in the intake bypass valve can be efficiently exhausted. Therefore, even if the engine is cooled after the engine is stopped, condensed water is not generated by the moisture in the EGR gas. There is no possibility that the condensed water will corrode the driving part inside the intake bypass valve or the condensed water freezes to fix the driving part, thereby hindering normal operation of the intake bypass valve.
According to the invention of (3), when the intake bypass valve is changed from the open state to the closed state, the check valve is opened to suck in fresh air that has not introduced EGR from the intake passage into the pressure equilibrium chamber. Then, after reducing the remaining exhaust gas recirculation gas concentration, when the intake bypass valve is changed from the closed state to the open state, the check valve is closed and the exhaust gas recirculation gas having a reduced concentration in the pressure equilibrium chamber is exhausted to the inflow passage. To do. By repeating this, the concentration of the exhaust gas recirculation gas remaining in the pressure equilibrium chamber can be set to a predetermined value or less. Even if the exhaust gas recirculation gas cannot be completely eliminated, even if the concentration becomes a predetermined value or less, even if the engine is stopped and the intake bypass valve is cooled, no condensed water is generated and there is no problem. Further, when the ABV 42 is changed from the valve open state to the valve closed state, the compression resistance of the escape chamber 88 is lost, so that the responsiveness when the ABV 42 is changed from the valve open state to the valve closed state can be improved.

According to the invention of (4), after the engine is stopped, the exhaust gas recirculation gas remaining inside the intake bypass valve can be excluded regardless of the operation of the vehicle, so that the operation is not affected.
According to the invention of (5), the exhaust gas recirculation gas remaining in the pressure equilibrium chamber is discharged to the surge tank through the scavenging passage. At this time, the surge tank is in a negative pressure state because the engine is operated at a light load and the intake air amount adjustment valve is closed, and the exhaust gas recirculation gas remaining in the pressure equilibrium chamber can be exhausted. When the surge tank is in the positive pressure state, the check valve is closed, so that the exhausted exhaust gas does not return to the scavenging passage. Then, by repeating this, the concentration of the exhaust gas recirculation gas remaining in the pressure equilibrium chamber can be set to a predetermined value or less. Even if the exhaust gas recirculation gas cannot be completely eliminated, even if the concentration becomes a predetermined value or less, even if the engine is stopped and the intake bypass valve is cooled, no condensed water is generated and there is no problem.
Further, since the intake pipe negative pressure is guided to the escape chamber 88 of the ABV 42 during deceleration, the responsiveness when the ABV 42 is changed from the closed state to the open state can be improved. In addition, the electromagnetic coil can be reduced in size.

According to the invention of (6), the exhaust gas recirculation gas remaining in the pressure equilibrium chamber is discharged to the surge tank through the scavenging passage. At this time, the surge tank is in a negative pressure state because the engine is operated with a light load and the intake air amount adjustment valve is closed, and the inflow path pressure (compressor outlet pressure) is positive. The exhaust gas recirculation gas remaining in can be exhausted. Since EGR cut and light load operation are always performed before the engine is stopped, exhaust recirculation gas remaining in the intake bypass valve can be scavenged before soaking, so even if the engine is stopped and the intake bypass valve is cooled, There is no problem because no condensed water is generated.
Further, since the intake pipe negative pressure is guided to the escape chamber 88 of the ABV 42 during deceleration, the responsiveness when the ABV 42 is changed from the closed state to the open state can be improved. In addition, the electromagnetic coil can be reduced in size.
The effect of the invention of (7) will be described. In the inventions of (5) and (6), the amount of air flowing into the intake pipe from the intake bypass valve during deceleration and idling is mainly affected by the clearance of the sliding portion inside the intake bypass valve. When the clearance becomes large due to variations due to tolerances or aging wear for each product, there is a problem that problems such as deterioration of deceleration and an increase in idle rotation occur. According to the above invention, since the throttle is provided, it is possible to prevent excessive air from flowing into the surge tank.
Further, since the intake pipe negative pressure is guided to the escape chamber 88 of the ABV 42 during deceleration, the responsiveness when the ABV 42 is changed from the closed state to the open state can be improved. In addition, the electromagnetic coil can be reduced in size.

According to the invention of (8), since the scavenging of the intake bypass valve can be limited to the EGR cut condition, the exhaust amount flowing in the surge tank can be suppressed. This is because the EGR gas contains exhaust particulates and therefore suppresses the flow into the surge tank as much as possible.
According to the invention of (9), when the exhaust gas recirculation valve is closed, the air pressurized by the pressure pump can be directly supplied into the pressure equilibrium chamber, so that the exhaust gas recirculation remaining in the pressure equilibrium chamber can be supplied. Gas can be surely scavenged.
According to the invention of (10), the exhaust gas recirculation gas remaining in the pressure equilibrium chamber can be surely scavenged because the negative pressure pump can suck directly from the pressure equilibrium chamber when the exhaust gas recirculation valve is closed. be able to.

According to the invention of (11), the scavenging means repeatedly opens and closes the intake bypass valve in accordance with the EGR amount when the exhaust gas recirculation valve is closed. The object can be achieved only by the control method using the conventional intake bypass valve not equipped with the.
That is, when shifting from the valve-closed state to the valve-opened state, the movable body moves upward, and the air in the escape chamber moves to the pressure equilibrium chamber through the gap on the outer periphery of the movable body. As a result, the exhaust gas recirculation gas remaining in the pressure transfer chamber is discharged from the vent hole of the shielding plate to the intake bypass passage. Thereafter, when the valve opening state is shifted to the valve closing state, the movable body moves downward, and new air in the intake bypass passage flows into the pressure equilibrium chamber. Furthermore, the air that has flowed into the pressure equilibrium chamber moves to the escape chamber through the gap on the outer periphery of the movable body. As a result, new air flows into the escape chamber and the pressure transfer chamber.
By repeating this, the exhaust gas recirculation gas concentration in the pressure equilibrium chamber can be reduced. Even if the exhaust gas recirculation gas cannot be completely eliminated, even if the concentration becomes a predetermined value or less, even if the engine is stopped and the intake bypass valve is cooled, no condensed water is generated and there is no problem.
In this case, after the engine is stopped, new air does not enter the intake passage. Therefore, scavenging control is preferably performed before the engine is stopped. Moreover, when it is performed after the engine is stopped, it is necessary to increase the number of times of opening and closing.
According to the invention of (12), the amount of EGR gas remaining in the intake bypass valve is estimated from the operating state of the engine, and the intake bypass valve is repeatedly opened and closed according to the estimated amount of RGR gas. Therefore, the EGR gas remaining in the intake bypass valve can be efficiently exhausted.
(13) In the control device for an engine with a supercharger described in (12), the count is increased in accordance with a process condition that changes from non-supercharging to supercharging and an engine stop condition. When it is estimated that high-concentration EGR gas remains in the valve, the opening / closing is repeated many times, so that the concentration of EGR gas remaining in the intake bypass valve can be reliably lowered to a predetermined value or less. it can.

It is a figure which shows the whole structure of 1st Embodiment. It is sectional drawing which shows the structure of ABV42 of 1st Embodiment. It is a flowchart which shows the control method of 1st Embodiment. It is a flowchart which shows the control method of 2nd Embodiment. It is a figure which shows the whole structure of 3rd Embodiment. It is sectional drawing which shows the structure of ABV42 of 3rd Embodiment. It is a figure which shows the whole structure of 4th-2 embodiment. It is a figure which shows the structure of ABV42 of 4th Embodiment. It is a flowchart which shows the control method of 4th-2 embodiment. It is a figure which shows the whole structure of 5th Embodiment. It is a flowchart which shows the control method of 5th Embodiment. It is a figure which shows the whole structure of 6th Embodiment. It is sectional drawing which shows the structure of ABV42 of 6th Embodiment. It is a figure which shows the whole structure of 4th-1 embodiment. It is a flowchart which shows the control method of 6th Embodiment. It is a flowchart which shows the control method of 7th Embodiment.

<First Embodiment>
Hereinafter, a first embodiment of a control device for a supercharged engine according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing a gasoline engine system including a control device for an engine with a supercharger in this embodiment. This engine system includes a reciprocating engine 1. An intake passage 3 is connected to the intake port 2 of the engine 1, and an exhaust passage 5 is connected to the exhaust port 4. An air cleaner 6 is provided at the inlet of the intake passage 3. A supercharger 7 for boosting the intake air in the intake passage 3 is provided in the intake passage 3 downstream of the air cleaner 6 between the exhaust passage 5 and the intake passage 3.

The supercharger 7 includes a compressor 8 disposed in the intake passage 3, a turbine 9 disposed in the exhaust passage 5, and a rotating shaft 10 that connects the compressor 8 and the turbine 9 so as to be integrally rotatable. The supercharger 7 rotates the turbine 9 by the exhaust gas flowing through the exhaust passage 5 and integrally rotates the compressor 8 via the rotary shaft 10 to boost the intake air in the intake passage 3, that is, perform supercharging. It is like that.
An exhaust bypass passage 11 that bypasses the turbine 9 is provided in the exhaust passage 5 adjacent to the supercharger 7. A waste gate valve 12 is provided in the exhaust bypass passage 11. By adjusting the exhaust gas flowing through the exhaust bypass passage 11 by the waste gate valve 12, the exhaust gas flow rate supplied to the turbine 9 is adjusted, the rotational speeds of the turbine 9 and the compressor 8 are adjusted, and supercharging by the supercharger 7 is performed. The pressure is adjusted.

  An intake bypass passage 41 that bypasses the compressor 8 is provided in the intake passage 3 adjacent to the supercharger 7. The intake bypass passage 41 is provided with an intake bypass valve (hereinafter referred to as “ABV”) 42. By adjusting the intake air flowing through the intake bypass passage 41 by the ABV 42, the pressure difference between the inlet and the outlet of the compressor 8 is reduced, and surging is prevented. One end of a communication path 43 that communicates with the inside of the ABV 42 is connected to the ABV 42 in order to discharge the EGR gas remaining inside the ABV 42. The other end of the communication passage 43 is connected to the intake passage 3 upstream of the compressor 8 and upstream of the outlet 17 a of the EGR passage 17.

  In the intake passage 3, an intercooler 13 is provided between the compressor 8 of the supercharger 7 and the engine 1. The intercooler 13 is for cooling the intake air that has been pressurized by the compressor 8 to a high temperature. A surge tank 3 a is provided in the intake passage 3 between the intercooler 13 and the engine 1. An electronic throttle device 14 that is an electric throttle valve is provided in the intake passage 3 downstream from the intercooler 13 and upstream from the surge tank 3a. The electronic throttle device 14 detects a butterfly throttle valve 21 disposed in the intake passage 3, a DC motor 22 for opening and closing the throttle valve 21, and an opening degree (throttle opening degree) TA of the throttle valve 21. And a throttle sensor 23 for performing the operation. The electronic throttle device 14 is configured such that the opening degree of the throttle valve 21 is adjusted by the throttle valve 21 being opened and closed by the DC motor 22 in accordance with the operation of the accelerator pedal 26 by the driver. In this embodiment, the electronic throttle device 14 corresponds to an example of an intake air amount adjustment valve of the present invention. The exhaust passage 5 downstream from the turbine 9 is provided with a catalytic converter 15 as an exhaust catalyst for purifying exhaust.

  The engine 1 is provided with an injector 25 for injecting and supplying fuel to the combustion chamber 16. Fuel is supplied to the injector 25 from a fuel tank (not shown). In this embodiment, the injector 25 corresponds to an example of the fuel supply means of the present invention. The engine 1 is provided with a spark plug 29 corresponding to each cylinder. Each spark plug 29 is ignited by receiving a high voltage output from the igniter 30. The ignition timing of each spark plug 29 is determined by the high voltage output timing from the igniter 30. The spark plug 29 and the igniter 30 constitute an ignition device.

  In this embodiment, the engine 1 is provided with an EGR device for realizing a large amount of EGR. The EGR device includes an exhaust gas recirculation passage (EGR passage) 17 that causes a part of the exhaust gas discharged from the combustion chamber 16 of the engine 1 to the exhaust passage 5 to flow into the intake passage 3 as EGR gas and recirculate to the combustion chamber 16, and an EGR passage. And an exhaust gas recirculation valve (EGR valve) 18 provided in the EGR passage 17 in order to adjust the flow of EGR gas in the engine 17. In this embodiment, the EGR device is a low-pressure loop type, and the EGR passage 17 is provided between the exhaust passage 5 downstream from the catalytic converter 15 and the intake passage 3 upstream from the compressor 8. That is, a part of the exhaust gas flowing through the exhaust passage 5 flows as EGR gas to the intake passage 3 through the EGR passage 17 and recirculates to the combustion chamber 16, so that the outlet 17 a of the EGR passage 17 has an intake passage 3 upstream of the compressor 8. Connected to. Further, the inlet 17 b of the EGR passage 17 is connected to the exhaust passage 5 downstream from the catalytic converter 15. The EGR passage 17 is provided with an EGR cooler 20 for cooling the EGR gas flowing through the passage 17. In this embodiment, the EGR valve 18 is disposed in the EGR passage 17 downstream of the EGR cooler 20.

  As shown in FIG. 1, the EGR valve 18 is configured as a poppet valve and as an electric valve. That is, the EGR valve 18 includes a valve body 32 that is driven by the DC motor 31. The valve body 32 has a substantially conical shape, and is provided so as to be seated on a valve seat 33 provided in the EGR passage 17. The DC motor 31 includes an output shaft 34 that is configured to be able to reciprocate (stroke) in a straight line. A valve body 32 is fixed to the tip of the output shaft 34. The output shaft 34 is supported by a housing constituting the EGR passage 17 via a bearing 35. The opening degree of the valve body 32 with respect to the valve seat 33 is adjusted by moving the output shaft 34 of the DC motor 31 in a stroke. The output shaft 34 of the EGR valve 18 is provided so as to be able to perform a stroke movement by a predetermined stroke from a fully closed state in which the valve body 32 is seated on the valve seat 33 to a fully open state in which the valve body 32 contacts the bearing 35. In this embodiment, in order to realize a large amount of EGR, the opening area of the valve seat 33 is enlarged as compared with the conventional technique. Accordingly, the valve body 32 is enlarged.

  In this embodiment, in order to execute fuel injection control, ignition timing control, intake air amount control, EGR control, supercharging control, and the like according to the operating state of the engine 1, the injector 25, the igniter 30, and the electronic throttle device 14 are controlled. The DC motor 22, the DC motor 31 of the EGR valve 18, and the ABV 42 are controlled by an electronic control unit (ECU) 50 in accordance with the operating state of the engine 1. The ECU 50 stores in advance a central processing unit (CPU), a predetermined control program and the like, various memories for temporarily storing a calculation result of the CPU, and the like, an external input circuit connected to these parts, and an external And an output circuit. In this embodiment, the ECU 50 corresponds to an example of a control unit of the present invention. An igniter 30, an injector 25, DC motors 22 and 31, and an ABV 42 are connected to the external output circuit. The external input circuit is connected to various sensors 27 and 51 to 55 corresponding to an example of the operating state detecting means of the present invention for detecting the operating state of the engine 1 including the throttle sensor 23, and various engine signals are inputted. It has come to be.

  Here, in addition to the throttle sensor 23, various sensors include an accelerator sensor 27, an intake pressure sensor 51, a rotation speed sensor 52, a water temperature sensor 53, an air flow meter 54, an air-fuel ratio sensor 55, and an intake air temperature sensor 56 (not shown). Provided. In addition, an ignition switch 57 (not shown) is provided. The accelerator sensor 27 detects an accelerator opening ACC that is an operation amount of the accelerator pedal 26. The intake pressure sensor 51 detects the intake pressure PM in the surge tank 3a. That is, the intake pressure sensor 51 detects the intake pressure PM in the surge tank 3a downstream from the throttle valve 21. The rotational speed sensor 52 detects the rotational angle (crank angle) of the crankshaft 1a of the engine 1 and detects the change in the crank angle as the rotational speed (engine rotational speed) NE of the engine 1. The water temperature sensor 53 detects the cooling water temperature THW of the engine 1. The air flow meter 54 detects the intake air amount Ga flowing through the intake passage 3 immediately downstream of the air cleaner 6. The air-fuel ratio sensor 55 is provided in the exhaust passage 5 immediately upstream of the catalytic converter 15, and detects the air-fuel ratio A / F in the exhaust.

In this embodiment, the ECU 50 controls the EGR valve 18 in order to execute the EGR control in accordance with the operation state of the engine 1 in the entire operation region of the engine 1. Further, the ECU 50 normally controls the opening of the EGR valve 18 based on the operating state detected during the acceleration operation or the steady operation of the engine 1, and the EGR valve 18 when the engine 1 is stopped, idle operation, or deceleration operation. Is controlled to be fully closed.
In this embodiment, the ECU 50 controls the electronic throttle device 14 based on the accelerator opening ACC in order to drive the engine 1 in response to a driver's request. Further, the ECU 50 controls to open the electronic throttle device 14 based on the accelerator opening ACC during acceleration operation or steady operation of the engine 1 and closes the electronic throttle device 14 when the engine 1 is stopped or decelerated. It has become. Thereby, the throttle valve 21 is opened during the acceleration operation or the steady operation of the engine 1 and is fully closed when the engine 1 is stopped or decelerated.

Next, the configuration of the ABV 42 will be described in detail. FIG. 2 shows the ABV 42 in a sectional view. As shown in FIG. 2, the ABV 42 is installed in the casing 61 of the supercharger 7. The ABV 42 is arranged vertically so that the opening / closing direction of a valve member 62 (described later) is the vertical direction (vertical direction). An intake bypass passage 41 is formed in the casing 61. The intake bypass passage 41 has an inflow passage 63 and an outflow passage 64. A valve seat 65 is formed between the inflow path 63 and the outflow path 64. A mounting hole 66 is formed in the casing 61 at a concentric position above the valve seat 65. The inner diameter of the mounting hole 66 is larger than the inner diameter of the valve seat 65.
The ABV 42 includes an electromagnetic device 67. The electromagnetic device 67 includes a housing 68, a coil 69, a fixed core 70, an end plate 71, and the like. The housing 68 is formed in a cylindrical shape. The coil 69 is accommodated in the housing 68 while being wound around the bobbin 72. The fixed core 70 is formed in a cylindrical shape and is disposed in the hollow portion of the bobbin 72. The end plate 71 is formed in an annular plate shape, and is provided concentrically on the lower end surface of the bobbin 72. The housing 68 as a stator, the fixed core 70 and the end plate 71 are each formed of a magnetic material such as iron, and form a fixed magnetic circuit. A mounting flange 68 a that protrudes outward in the radial direction is formed at the lower end of the housing 68. An inner flange 68b is formed inside the mounting flange 68a. The outer peripheral portion of the end plate 71 is sandwiched between the inner flange 68b and the bobbin 72.

  A guide shaft 73 protruding downward is concentrically attached to the lower end portion of the fixed core 70. A cylindrical movable core 74 is fitted to the guide shaft 73 through a resin guide sleeve 75 so as to be reciprocally movable in the vertical direction. The movable core 74 is loosely fitted in the hollow portion of the end plate 71. The movable core 74 is formed of a magnetic material such as iron. The guide sleeve 75 is fixed to the movable core 74 by press fitting or the like. A coil spring 76 fitted to the guide shaft 73 is interposed between the guide sleeve 75 and the fixed core 70. The coil spring 76 biases the movable core 74 away from the fixed core 70, that is, downward. In this embodiment, the coil spring 76 corresponds to an example of the elastic member of the present invention.

When the coil 69 of the electromagnetic device 67 is not excited, the biasing force of the coil spring 76 biases the movable core 74 away from the fixed core 70, that is, downward. When the coil 69 of the electromagnetic device 67 is excited, the movable core 74 is attracted to the fixed core 70 side, that is, upward, against the urging force of the coil spring 76 by the electromagnetic force.
At the lower end of the movable core 74, an attachment cylinder portion 74a that reduces the outer diameter is formed. A circular dish-shaped stopper plate 77, an annular diaphragm 78, a reverse cup-shaped cylindrical member 79, and a retaining ring 80 are sequentially and concentrically fitted to the mounting cylindrical portion 74a, and the mounting cylindrical portion 74a It is fixed by caulking all around the lower end. The outer peripheral portion of the stopper plate 77 abuts on the end plate 71 when the movable core 74 moves upward, and restricts further upward movement of the movable core 74. The diaphragm 78 is formed from a resinous rubber-like elastic material. The inner peripheral portion of the diaphragm 78 is sandwiched between the stopper plate 77 and the cylindrical member 79.

An annular diaphragm guide 81 made of resin is concentrically connected to the lower surface side of the inner flange 68 b of the housing 68. Between the inner flange 68b and the diaphragm guide 81, the outer peripheral portion of the diaphragm 78 is sandwiched. As a result, a sealed pressure equilibrium chamber 82 is formed between the various fixed-side members of the electromagnetic device 67 and the movable core 74.
In the movable core 74, a plurality of lateral holes 74b that are adjacent to the upper side of the stopper plate 77 and penetrate in the radial direction are formed at equal intervals in the circumferential direction. The lateral hole 74 b communicates the hollow portion 74 c of the movable core 74 and the pressure equilibrium chamber 82. The total opening area of the plurality of horizontal holes 74 b is set to be approximately the same as the opening area of the hollow portion 74 c of the movable core 74. A series of pressure introduction passages 83 are formed by the internal space 79a of the cylindrical member 79, the hollow portion 74c of the movable core 74, and the lateral hole 74b.

A resin shielding plate 84 is provided at the lower end of the cylindrical member 79. The shielding plate 84 is formed in a disc shape. On the lower surface of the shielding plate 84, a valve portion 84a made of an annular protrusion is formed concentrically. The shielding plate 84 is formed with a plurality of ventilation holes 84b penetrating in the thickness direction at equal intervals in the circumferential direction. Each vent hole 84b has a circular shape and is disposed on the inner peripheral side of the valve portion 84a. The total opening area of the plurality of vent holes 84 b is set to be approximately the same as the opening area of the hollow portion 74 c of the movable core 74. A pressure receiving wall portion that receives air pressure is formed by a plate-like portion excluding the vent hole 84b on the inner peripheral side of the valve portion 84a of the shielding plate 84.
The shielding plate 84 is fitted into the lower end opening of the cylindrical member 79 so as to close the opening. The shielding plate 84 is fixed to the cylindrical member 79 in a concentric and vertically positioned state. The caulking portion of the cylindrical member 79 is referred to as a caulking portion. The pressure receiving wall portion of the shielding plate 84 is disposed with a positional relationship overlapping the hollow portion 74 c of the movable core 74 in a projected view as viewed from the axial direction of the movable core 74. The ventilation hole 84b of the shielding plate 84 is disposed with a positional relationship that does not overlap the hollow portion 74c of the movable core 74 in a projected view as viewed from the axial direction of the movable core 74. The valve member 62 is configured by the shielding plate 84 having the valve portion 84 a and the tubular member 79. The movable core 85, the stopper plate 77, the inner periphery of the diaphragm 78, the retaining ring 80, the valve member 62, and the like constitute a movable body 85 that can reciprocate in the vertical direction. The housing 68, the coil 69, the fixed core 70, the end plate 71, the guide shaft 73, and the outer periphery of the diaphragm 78 constitute a fixed side member 86.

The ABV 42 is installed on the casing 61. Specifically, the housing 68 is disposed on the casing 61 so as to be concentric with the mounting hole 66 and close the mounting hole 66. The mounting flange 68a of the housing 68 is fixed to the casing 61 by fastening or the like. The cylindrical member 79 is disposed in the outflow path 64 from the mounting hole 66 of the casing 61. The valve portion 84 a of the shielding plate 84 corresponds to the valve seat 65. An O-ring 87 for sealing is provided between the casing 61 and the mounting flange 68a.
An escape chamber 88 that allows the movable core 74 to move up and down is formed between the fixed core 70 and the upper end of the movable core 74. The fixed core 70 and the housing 68 are formed with a scavenging passage 89 that allows the escape chamber 88 to communicate with the outside. The scavenging passage 89 communicates with the pressure balance chamber 82 via a clearance chamber 88 and a gap between the movable core 74 and the end plate 71. The scavenging passage 89 is a passage for discharging the EGR gas remaining in the pressure balance chamber 82 and scavenging the pressure balance chamber 82. A pipe joint 90 is fixed to the upper portion of the housing 68 corresponding to the outlet of the scavenging passage 89. One end of the communication passage 43 described above is connected to the pipe joint 90. A check valve 44 composed of a reed valve is provided inside the pipe joint 90. The check valve 44 is provided so as to stop the flow of air from the scavenging passage 89 to the communication passage 43 and to allow the reverse air flow.

Next, the operation of the ABV 42 will be described. When the electromagnetic device 67 is not energized (non-excited), the movable body 85 including the movable core 74 is urged away from the fixed core 70 by the urging force of the coil spring 76. As a result, the valve portion 84a of the shielding plate 84 of the valve member 62 is seated on the valve seat 65, and the valve is closed. On the other hand, when the electromagnetic device 67 is energized (excited), the movable body 85 moves in the opening direction against the urging force of the coil spring 76 by the electromagnetic force. As a result, the valve portion 84a is separated from the valve seat 65 and is opened.
In the valve closed state of the ABV 42, the diaphragm 78 defines the pressure equilibrium chamber 82 corresponding to the outflow path 64. The inflow path 63 and the pressure equilibrium chamber 82 act on the pressure equilibrium chamber 82 via the vent hole 84 b of the shielding plate 84 and the pressure introduction passage 83. For this reason, the pressure of the air applied before and after the valve member 62, that is, the inflow path 63 side and the pressure equilibrium chamber 82 side is balanced. Therefore, the urging force of the coil spring 76 and the electromagnetic force of the electromagnetic device 67 are reduced.

  By the way, when the ABV 42 is opened, particularly when the valve is opened, most of the high-pressure air flowing out from the inflow path 63 through the hollow portion of the valve seat 65 to the outflow path 64 collides with the pressure receiving wall portion of the shielding plate 84. . At the same time, most of the air flows into the outflow passage 64, but a part of the air flows into the pressure equilibrium chamber 82 from the vent hole 84 b of the shielding plate 84 through the pressure introduction passage 83. At this time, the dynamic pressure of the air acting on the pressure equilibrium chamber 82 through the vent hole 84b of the shielding plate 84 is the movement of the air acting on the pressure equilibrium chamber 82 through the hollow portion 74c of the movable core 74 when the shielding plate 84 is omitted. Lower than pressure. Therefore, the dynamic pressure of air acting on the pressure equilibrium chamber 82 at the start of valve opening is reduced. Thereby, compared with the conventional example, the pressure of the air in the pressure equilibrium chamber 82 is easily lowered, and the valve opening time required from the start to the end of the valve opening is shortened. Further, the internal space of the valve member 62 by the tubular member 79 and the shielding plate 84 is larger in passage cross-sectional area than the opening area (passage area) of the hollow portion 74c of the movable core 74 and the vent hole 84b of the shielding plate 84. Therefore, it functions as a buffer chamber for the dynamic pressure of air acting on the pressure balance chamber 82 (same as the internal space 79a of the cylindrical member 79). The buffer chamber corresponds to the inlet side passage of the pressure introduction passage 83.

  Here, in the ABV 42 of this embodiment, the EGR gas into which the EGR gas flows into the pressure equilibrium chamber 82 may stay in the pressure equilibrium chamber 82. When the EGR gas staying in the ABV 42 is cooled after the engine is stopped or the like, condensed water may be generated due to moisture in the EGR gas, and this condensed water corrodes the driving part inside the ABV 42. There is a risk that the normal operation of the ABV 42 may be hindered by causing the driving unit to be fixed by freezing the condensed water. Therefore, in this embodiment, the ECU 50 performs the following scavenging control in order to prevent the EGR gas from staying in the ABV 42 and prevent the condensed water from being generated in the ABV 42. ing.

FIG. 3 is a flowchart showing an example of processing contents of this scavenging control. When the process proceeds to this routine, in step 100, the ECU 50 determines whether or not the EGR is switched from on to off. If this determination is negative, the ECU 50 returns the process to step 100. If the determination result is affirmative, the ECU 50 proceeds to step 110.
In step 110, the ECU 50 determines whether or not the operating state of the engine 1 is in a non-supercharging region. If this determination result is negative, the ECU 50 proceeds to step 230. If the determination result is affirmative, the ECU 50 proceeds to step 120.
In step 230, the ECU 50 resets the scavenging completion determination flag XABVOC to “0”. This flag XABVOC is reset to “1” when scavenging of the ABV 42 is completed, and to “0” when scavenging is not completed.
Next, in step 240, the ECU 50 resets the ABV valve opening control flag XABVO to “0”. The flag XABVO is reset to “1” when the ABV 42 is opened, and is reset to “0” when the ABV 42 is closed.

Next, in step 250, the ECU 50 resets the ABV scavenging number ABVOC described later to “0”.
Next, in step 260, the ECU 50 controls the ABV 42 to be closed. Thereafter, the ECU 50 returns the process to step 100.
On the other hand, in step 120, the ECU 50 determines whether or not the scavenging completion determination flag XABVOC is “0”. If the determination result is negative, the ECU 50 proceeds to step 240. Subsequently, Step 250 and Step 260 are executed. If the determination result is affirmative, the ECU 50 proceeds to step 130.
In step 130, the ECU 50 determines whether or not the ABV valve opening control flag XABVO is “0”.
In step 140, the ECU 50 controls the valve opening of the ABV 42. Next, in step 150, the ECU 50 waits for a predetermined time to elapse after the valve opening, and then proceeds to step 160.
In step 160, the ECU 50 sets the ABV valve opening control flag XABVO to “1” and returns the process to step 100.

On the other hand, in step 170, the ECU 50 controls the ABV 42 to be closed. Next, in step 180, the ECU 50 waits for a predetermined time to elapse after the valve is closed and proceeds to step 190.
In step 190, the ECU 50 calculates the current ABV scavenging number ABVOC (i) by adding “1” to the ABV scavenging number ABVOC (i−1) up to the previous time.
Next, at step 200, the ECU 50 determines whether or not the ABV scavenging frequency ABVOC is greater than a predetermined value C1. If the determination result is affirmative, the ECU 50 proceeds to step 210. If this determination result is negative, the ECU 50 proceeds to step 220.
In step 210, the ECU 50 sets the scavenging completion determination flag XABVOC to “1”, assuming that scavenging has been completed, and returns the process to step 100.
In step 220, assuming that scavenging has not been completed, the ECU 50 resets the scavenging completion determination flag XABVOC to “0” and returns the process to step 100.
According to the control described above, the ECU 50 alternately repeats the opening and closing of the ABV 42 a predetermined number of times when the EGR is switched from on to off and the operating state of the engine 1 is in the non-supercharging range. ing.

According to the control device for an engine with a supercharger of the present embodiment, scavenging means 89, 44, 43 for scavenging the pressure equilibrium chamber 82 in order to exhaust the exhaust gas recirculation gas remaining in the pressure equilibrium chamber 82 of the ABV 42. Since the EGR gas remaining in the ABV 42 can be surely eliminated, condensed water is not generated by the water in the EGR gas even if it is cooled after the engine is stopped. There is no possibility that the condensed water corrodes the driving part inside the ABV 42, or the condensed water freezes to fix the driving part, thereby hindering the normal operation of the ABV 42.
Further, when the ABV 42 is changed from the open state to the closed state, the check valve 44 is opened and the outside air is sucked into the pressure equilibrium chamber 82 from the communication passage 43. Then, after reducing the remaining exhaust gas recirculation gas concentration, when the ABV 42 is changed from the closed state to the open state, the check valve 44 is closed, and the exhaust gas recirculation gas having a reduced concentration in the pressure equilibrium chamber 82 is supplied to the inflow path. Exhaust. By repeating this, the concentration of the exhaust gas recirculation gas remaining in the pressure equilibrium chamber 82 can be set to a predetermined value or less. Even if the exhaust gas recirculation gas cannot be completely eliminated, even if the concentration becomes a predetermined value or less, even if the engine is stopped and the intake bypass valve is cooled, no condensed water is generated and there is no problem.

Second Embodiment
Next, a second embodiment of the present invention will be described. Since most contents of the second embodiment are the same as those of the first embodiment, description of the same contents will be omitted, and only differences will be described in detail.
The second embodiment is different only in the control method. FIG. 4 is a flowchart showing the control method. Also in the flowchart, the difference is that S100 is changed to S101. Also, there is no S230.
In the first embodiment, the condition for performing the scavenging process is EGR cut and the non-supercharging region, but in the second embodiment, the engine is stopped. That is, scavenging is performed when the ignition key (IG) is turned off from on in S101.
According to the present embodiment, after the engine is stopped, the exhaust gas recirculation gas remaining in the ABV 42 can be excluded regardless of the operation of the vehicle, so that the operation is not affected.

<Third Embodiment>
Next, a third embodiment of the present invention will be described. Since most of the contents of the third embodiment are the same as those of the first embodiment, description of the same contents will be omitted, and only differences will be described in detail.
FIG. 5 shows the overall configuration of the third embodiment. Only differences from FIG. 1 will be described. Instead of the communication path 43, a communication path 91 is provided. That is, one end 91 b of the communication passage 91 is communicated with the pipe joint 90. The other end 91a of the communication passage 91 communicates with the intake passage 3 downstream from the electronic throttle device 14 that is an intake air amount adjusting valve.
FIG. 6 is a cross-sectional view showing the configuration of ABV42. Only differences from FIG. 2 will be described. A check valve 92 is provided instead of the check valve 44. The check valve 92 is attached to the outlet surface of the scavenging passage 89, allows a gas flow from the scavenging passage 89 toward the communication passage 91, and prevents a gas flow from the communication passage 92 toward the scavenging passage 89.

Next, functions and effects of the third embodiment will be described.
Since the engine light load (idle, deceleration) region is EGR cut, the inflow path 63 and the outflow path 64 are fresh. This new air flows from the vent hole 84b and scavenges the EGR gas. That is, the exhaust gas recirculation gas remaining in the pressure equilibrium chamber 82 is discharged to the surge tank 3 a through the scavenging passage 89. At this time, the surge tank 3a is in a negative pressure state because the engine 1 is operated at a light load and the throttle valve 21 is closed, and the exhaust gas recirculation gas remaining in the pressure equilibrium chamber 82 can be exhausted. When the surge tank 3a is in a positive pressure state, the check valve 92 is closed, so that the exhausted recirculated gas does not return to the scavenging passage 89. By repeating this, the concentration of the exhaust gas recirculation gas remaining in the pressure equilibrium chamber 82 can be made equal to or less than a predetermined value. Even if the exhaust gas recirculation gas cannot be completely eliminated, even if the concentration becomes a predetermined value or less, even if the engine is stopped and the intake bypass valve is cooled, no condensed water is generated and there is no problem.
Further, since the intake pipe negative pressure is guided to the escape chamber 88 of the ABV 42 during deceleration, the responsiveness when the ABV 42 is changed from the closed state to the open state can be improved.

<Fourth embodiment>
Next, a fourth embodiment of the present invention will be described. Since most of the content is the same as that of the third embodiment, the description of the same content will be omitted, and only the differences will be described in detail.
FIG. 7 shows the overall configuration of the fourth embodiment. Only differences from FIG. 5 will be described. A feature of the fourth embodiment is that the communication passage 91 is provided with a throttle 93 and an on-off valve (VSV94).
FIG. 8 is a sectional view showing the configuration of the ABV 42 according to the fourth embodiment. The difference from FIG. 1 is that the check valve 44 is not provided. As an embodiment, as shown in FIG. 14, only the diaphragm 93 may be provided and the VSV 94 may be omitted. This is referred to as a 4-1 embodiment. Further, an embodiment including both the diaphragm 93 and the VSV 94 is referred to as a 4-2 embodiment.
In the third embodiment, the amount of air flowing from the ABV 42 into the intake pipe during deceleration and idling is mainly affected by the clearance of the sliding portion inside the ABV 42. When the clearance becomes large due to variations due to tolerances or aging wear for each product, there is a problem that problems such as deterioration of deceleration and an increase in idle rotation occur. According to the 4-1 embodiment, since the throttle 93 is provided, it is possible to prevent excessive air from flowing into the surge tank 3a.

Next, the case where the diaphragm 93 and the VSV 94 are both provided (the 4-2 embodiment) will be described. FIG. 9 is a flowchart showing the control method according to the 4-2 embodiment. When the EGR cut (off) condition is affirmative (S300; YES) and the VSV flag is 0 (indicating that VSV 94 is off) (S310; YES), VSV 94 is turned on. After a predetermined time has elapsed (S330), the VSV flag is set to 1 (S340). When the EGR valve 18 is on (S300; NO), the VSV flag is set to 0 (S350), and the VSV 94 is turned off (S360).
As described above, in the 4-2 embodiment, control is performed so that the on-off valve 94 is opened only when the EGR cut (off) condition is satisfied.
According to the 4-2 embodiment, the scavenging of the ABV 42 can be limited to the EGR cut condition (the closed state of the EGR valve 18), so that the exhaust amount flowing into the surge tank 3a is suppressed. Can do. This is because the EGR gas contains exhaust particulates, and therefore suppresses the flow into the surge tank 3a as much as possible.

<Fifth Embodiment>
Next, a fifth embodiment of the present invention will be described. Since most contents of the fifth embodiment are the same as those of the first embodiment, description of the same contents will be omitted, and only differences will be described in detail.
FIG. 10 shows the overall configuration of the fifth embodiment. The difference from FIG. 1 is that a pressurizing pump 96 or a negative pressure pump 97 is attached to the other end of the communication path 95. An embodiment in which the pressurizing pump 96 is attached is referred to as a 5-1th embodiment. An embodiment in which the negative pressure pump 97 is attached is referred to as a 5-2 embodiment.
A control method according to the fifth embodiment is shown in a flowchart in FIG. When the EGR cut (off) condition is affirmative (S400; YES) and the PUMP flag is 0 (indicating that the pressurization pump 96 or the negative pressure pump 97 is off) (S410; YES), The pressure pump 96 or the negative pressure pump 97 is turned on. After a predetermined time has elapsed (S430), the PUMP flag is set to 1 (S440). When the EGR valve 18 is on (S400; NO), the PUMP flag is set to 0 (S450), and the pressurization pump 96 or the negative pressure pump 97 is turned off (S460).
According to the 5-1th embodiment, when the EGR valve 18 is closed, the air pressurized by the pressurizing pump 96 can be directly supplied into the pressure equilibrium chamber 82. The exhaust gas recirculation gas remaining in the gas can be surely scavenged.
According to the 5-2 embodiment, when the EGR valve 18 is closed, the negative pressure pump 97 can suck directly from the pressure equilibrium chamber 82, so that the exhaust gas remaining in the pressure equilibrium chamber 82 is exhausted. The reflux gas can be surely scavenged.

<Sixth Embodiment>
Next, a sixth embodiment of the present invention will be described. Since most contents of the fifth embodiment are the same as those of the first embodiment, description of the same contents will be omitted, and only differences will be described in detail.
FIG. 12 shows the overall configuration of the sixth embodiment. The difference from FIG. 1 is that the communication path 43 is not provided. FIG. 13 shows the configuration of the ABV 42 according to the sixth embodiment. The difference from FIG. 2 is that the ABV 42 does not include the scavenging passage 89.
The sixth embodiment is characterized by a control method. That is, when the ABV 42 shifts from the closed state to the open state, the movable body 85 moves upward, and the air in the escape chamber 88 moves to the pressure equilibrium chamber 82 through the gap on the outer periphery of the movable body 85. Thereby, the exhaust gas recirculation gas remaining in the pressure equilibrium chamber 82 is discharged from the vent hole 84 b of the shielding plate 84 to the intake bypass passage 41.
Thereafter, when the ABV 42 shifts from the valve open state to the valve close state, the movable body 85 moves downward, and new air in the intake bypass passage 41 flows into the pressure equilibrium chamber 82. Further, the air that has flowed into the pressure equilibrium chamber 82 moves to the escape chamber 88 through a gap on the outer periphery of the movable body 85. As a result, new air flows into the escape chamber 88 and the pressure balance chamber 82.
Thereby, the density | concentration of the exhaust gas recirculation gas in the escape chamber 88 and the pressure equilibrium chamber 82 falls. By repeating this, the exhaust gas recirculation gas concentration in the pressure equilibrium chamber 82 can be reduced. Even if the exhaust gas recirculation gas cannot be completely eliminated, even if the concentration becomes a predetermined value or less, even if the engine is stopped and the intake bypass valve is cooled, no condensed water is generated and there is no problem.

If the ABV 42 is repeatedly opened and closed, the concentration of the EGR gas remaining in the ABV 42 can be reduced. However, if the same number of times of opening and closing is always performed, there is a problem that the life of the ABV 42 is shortened. Therefore, in the present embodiment, the concentration of EGR gas remaining in the ABV 42 is estimated, and when the concentration is estimated to be high, the number of repetitions of opening and closing is increased, but the concentration is estimated to be low. In such a case, the number of times of opening and closing is reduced.
A method for estimating the EGR gas concentration will be described. FIG. 15 shows a flowchart. When the EGR is on (S500; NO), if it is the supercharging region (S510; YES), the scavenging completion determination flag XABVOC is set to “0” (S520). Next, if the supercharging determination flag XPMP = 0 (S530; YES), it is determined that it is in the non-supercharging region, it is determined that EGR gas has entered the ABV 42, and the ABV scavenging count ABVOC is counted. Is increased by α (S540). Here, α is a scavenging integration counter value each time the non-supercharging is changed to the supercharging. Thereby, the number of scavenging is added according to the number of times of entering the supercharging region (that is, estimating the assumed inflow EGR amount).
Next, if ABVOC is less than the predetermined value E (S550; YES), the supercharging determination flag XPMP = 1 is set (S570). When ABVOC is equal to or larger than the predetermined value E (S550; NO), ABVOC-E is calculated (S560), and the process proceeds to S570. Here, E is a guard value of the scavenging integration counter, that is, an upper limit value of the number of scavenging times.
On the other hand, if it is not the supercharging region (S510; NO), the supercharging determination flag XPMP = 0 is set (S511), and the process returns to the return.

When the EGR is turned off (S500; YES), if it is a non-supercharging region (S580; YES), the scavenging completion flag ABVOC is checked (S590). If the ABVOC flag is not set (S590; YES), the open / close flag XABVO is checked. If the XABVO flag is not set (S600; YES), it is determined that the ABV 42 is in a closed state, and the valve opening control of the ABV 42 is performed (S610). Next, after As is opened for a predetermined time (S620; YES), XABVO = 1 is set and the process returns.
On the other hand, if it is not the non-supercharging range (S580; NO), XABVOC = 0 is set (S710). Next, XABVO = 0 is set (S720), "0" is inserted into ABVOC (S730), and ABV valve closing control is performed (S740).
On the other hand, if the scavenging completion flag is set (S590; NO), XPMP = 0 is set (S700), and the process proceeds to S720.
On the other hand, if the open / close flag is not set (S600; NO), it is determined that the ABV 42 is in the valve open state, and the valve closing control of the ABV 42 is performed (S640). Next, after Bs is closed for a predetermined time (S650), β is subtracted from ABVOC by S (S660). Here, β is a scavenging subtraction counter for each opening and closing of the ABV 42 at the time of EGR cut. α> β. When the ABV 42 is opened and closed during the EGR cut, the concentration of EGR gas remaining in the ABV 42 is lowered, so that the necessary number of scavenging times is reduced.
Next, when ABVOC is zero or negative (S670; YES), XABVOC = 1 is set (S690), and the process returns to RETURN. If ABVOC is not zero or negative (S670; NO), XABVOC = 0 is set (S680), and the process returns.

  According to this flowchart, since the number of times of opening and closing for scavenging the ABV 42 is increased according to the number of process conditions that change from non-supercharging to supercharging, the concentration of EGR gas remaining in the ABV 42 is high. Therefore, since the scavenging frequency is increased, the concentration of EGR gas remaining in the ABV 42 can be efficiently reduced. At the same time, since the ABV 42 is not subjected to a useless scavenging opening / closing operation, the durability of the ABV 42 can be improved.

Next, a seventh embodiment will be described. Since the seventh embodiment is different from the sixth embodiment only in a part of the flowchart, this point will be described in detail.
FIG. 16 shows a flowchart of the seventh embodiment. The flowchart of FIG. 15 is different in that after the valve closing control (S640) of the ABV 42 is performed, it is checked whether or not the engine is in an operating state (S800) and when the engine is operating (S800). YES), the process proceeds to S660, and when the engine is stopped (S800; NO), it is a point that is minus γ from ABVOC (S810).
Here, γ is minus the necessary number of scavenging operations because the EGR gas concentration remaining in the ABV 42 decreases when the ABV 42 is opened and closed while the EGR cut and the engine stop are performed simultaneously. . Here, β> γ. This is because, when the engine is stopped, there is no flow of fresh air on the inflow path 63 side. Therefore, compared with the opening / closing operation of the ABV 42 when the EGR cut and the engine operation are performed simultaneously, This is because there is little scavenging of the EGR gas. Therefore, it is necessary to increase the number of scavenging times when the engine is stopped.

In the sixth embodiment, when the ABV 42 is changed from the closed state to the open state and the movable body 85 is moved upward, it is necessary to move the movable body 85 as slowly as possible. This is because if the moving speed of the movable body 85 is fast, the air in the escape chamber 88 is only compressed, and does not flow from the gap on the outer periphery of the movable body 85 to the pressure equilibrium chamber 82.
For this purpose, it is necessary to reduce the attraction force of the coil 69 so that the electric power applied to the coil 69 is close to the minimum electric power that the movable body 85 can move. For this purpose, the amount of power may be controlled by voltage control or current control.

In addition, this invention is not limited to the said embodiment, In the range which does not deviate from the meaning of invention, it can implement as follows.
For example, in the present embodiment, the exhaust gas recirculation gas remaining in the pressure equilibrium chamber 82 has been mainly described, but the exhaust gas recirculation gas remaining in the escape chamber 88 may be considered in the same manner.

18 EGR valve 42 ABV (intake bypass valve)
43, 91 Communication passages 44, 92 Check valve 52 ECU
82 Pressure balancing chamber 84 Shield plate 85 Movable body 89 Scavenging passage 93 Restriction 94 VSV

Claims (13)

A turbocharger provided between an intake passage and an exhaust passage of the engine for boosting intake air in the intake passage;
The supercharger includes a compressor disposed in the intake passage, a turbine disposed in the exhaust passage, and a rotation shaft that connects the compressor and the turbine so as to be integrally rotatable.
An exhaust gas recirculation passage that causes a part of the exhaust gas discharged from the combustion chamber of the engine to flow into the intake passage as exhaust gas recirculation gas and recirculates to the combustion chamber;
An exhaust gas recirculation valve for adjusting the flow of exhaust gas recirculation gas in the exhaust gas recirculation passage;
The exhaust gas recirculation passage has an inlet connected to the exhaust passage downstream of the turbine and an outlet connected to the intake passage upstream of the compressor;
An intake bypass passage that bypasses between the intake passage downstream of the compressor and the intake passage upstream of the compressor;
An intake bypass valve for opening and closing the intake bypass passage;
The intake bypass valve includes a valve seat provided on the intake bypass passage, a movable body having a valve member provided so as to be seatable on the valve seat, drive means for driving the movable body, and the drive means A pressure equilibrium chamber that is provided and partitioned between the movable body and a pressure introduction path that is formed in the movable body and communicates with the intake bypass passage and the pressure equilibrium chamber;
An operating state detecting means for detecting the operating state of the engine;
In a control device for an engine with a supercharger comprising at least control means for controlling the exhaust gas recirculation valve and the intake bypass valve based on the detected operating state,
A supercharger-equipped engine control device comprising scavenging means for scavenging the pressure balance chamber to discharge exhaust gas recirculation gas remaining in the pressure balance chamber of the intake bypass valve. 2. The supercharger-equipped engine control device according to claim 1, wherein the scavenging means includes a scavenging flow path provided in the intake bypass valve and communicating with the pressure equilibrium chamber. The scavenging means is provided in the intake bypass valve and communicates with the pressure balance chamber, a communication passage that connects one end of the scavenging passage to the intake passage upstream of the compressor, the scavenging passage, A check valve that is provided in the communication passage, prevents a gas flow from the scavenging passage to the communication passage, and allows a gas flow from the communication passage to the scavenging passage;
The control means repeatedly opens and closes the intake bypass valve during the exhaust recirculation valve closing control in order to scavenge the exhaust recirculation gas remaining in the pressure equilibrium chamber in a non-supercharging region where the supercharger does not operate. The control device for an engine with a supercharger according to claim 1, wherein the control device is controlled.   The control device for an engine with a supercharger according to claim 3, wherein the control means repeatedly opens and closes the intake bypass valve when the engine is stopped. The intake passage is provided with an intake air amount adjustment valve for adjusting an intake air amount flowing through the intake passage,
The scavenging means is provided in the intake bypass valve, communicates with the pressure balance chamber, communicates with one end of the scavenging passage to the intake passage downstream of the intake air amount adjustment valve, and the scavenging A check valve provided in a passage or the communication passage, allowing a gas flow from the scavenging passage toward the communication passage, and blocking a gas flow from the communication passage toward the scavenging passage,
In order to scavenge the exhaust gas recirculation gas remaining in the pressure balance chamber, the negative pressure generated in the intake passage downstream of the intake air amount adjustment valve during light load operation of the engine in which the intake air amount adjustment valve is closed 2. The supercharger-equipped engine control device according to claim 1, wherein the control device acts on the pressure equilibrium chamber via the communication passage and the scavenging passage. The intake passage is provided with an intake air amount adjustment valve for adjusting an intake air amount flowing through the intake passage,
The scavenging means includes a scavenging passage that is provided in the intake bypass valve and communicates with the pressure equilibrium chamber; and a communication passage that communicates one end of the scavenging passage with the intake passage downstream of the intake air amount adjustment valve;
In order to scavenge the exhaust gas recirculation gas remaining in the pressure balance chamber, the negative pressure generated in the intake passage downstream of the intake air amount adjustment valve during light load operation of the engine in which the intake air amount adjustment valve is closed 2. The supercharger-equipped engine control device according to claim 1, wherein the control device acts on the pressure equilibrium chamber via the communication passage and the scavenging passage.   The control device for an engine with a supercharger according to claim 5 or 6, wherein a throttle is provided in the communication path.   The open / close valve is provided in the communication path, and the exhaust gas recirculation gas remaining in the pressure equilibration chamber is scavenged when the control means controls the exhaust gas recirculation valve to be closed. The engine control device with a supercharger according to claim 1. A scavenging passage communicating with the pressure equilibrium chamber, and a communication passage communicating one end of the scavenging passage with the intake passage upstream of the compressor;
A pressure pump is provided in the communication path;
The control means supplies gas from the pressurizing pump to the pressure equilibrium chamber through the communication passage and the scavenging passage when the exhaust gas recirculation valve is controlled to close, thereby remaining in the pressure equilibrium chamber. The control device for an engine with a supercharger according to claim 1, wherein the exhaust recirculation gas is pushed out and discharged. A scavenging passage communicating with the pressure equilibrium chamber, and a communication passage communicating one end of the scavenging passage with the intake passage upstream of the compressor;
A negative pressure pump is provided in the communication path;
The control means sucks gas from the pressure equilibrium chamber from the negative pressure pump through the communication passage and the scavenging passage when the exhaust gas recirculation valve is closed, and remains in the pressure equilibrium chamber. The control device for an engine with a supercharger according to claim 1, wherein the exhaust gas recirculation gas is sucked and discharged. 2. The supercharged engine according to claim 1, wherein when the exhaust gas recirculation valve is controlled to close, the scavenging means repeatedly opens and closes the intake bypass valve in accordance with an EGR amount. 3. Control device. An amount of EGR gas remaining in the intake bypass valve is estimated from an operating state of the engine, and a count number for repeatedly opening and closing the intake bypass valve is determined according to the estimated amount of RGR gas. The control device for an engine with a supercharger according to claim 11.   13. The supercharger-equipped engine control device according to claim 12, wherein the count number is increased under a process condition that changes from non-supercharging to supercharging and an engine stop condition.

Images