JP2009293489A - Intake device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intake device for an internal combustion engine suppressing excessiveness of an EGR amount when a flow control valve changes from a valve closed state to a valve opened state. <P>SOLUTION: The intake device is applied to an internal combustion engine 1 provided with an EGR passage 21 returning part of exhaust to an intake passage 10, and an opening adjustable EGR valve 22 provided in the EGR passage 21. The device is equipped with a bulkhead 17 partitioning the intake passage 10 into two passages 12A, 12B, and an opening adjustable tumble control valve (TCV) 18 provided in one passage 12A. In a process of changing from the valve closed state to the valve opened state of the TCV 18, the EGR valve 22 is controlled to a closed side such that a return amount of exhaust via the EGR passage 21 is reduced prior to completion of changing to the valve opened state of the TCV. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an intake device for an internal combustion engine applied to an internal combustion engine provided with an EGR passage that recirculates a part of exhaust gas to an intake passage and an EGR valve that is provided in the EGR passage and is adjustable in opening.

  In many cases, an internal combustion engine is provided with an exhaust gas recirculation device that recirculates a part of the exhaust gas extracted from the exhaust passage to the intake passage in order to reduce the emission temperature of nitrogen oxides by lowering the combustion temperature. As an intake device applied to such an internal combustion engine, an intake port is divided into two flow paths by a partition plate, a flow control valve is provided in one flow path, and an EGR passage is connected to the other flow path. (Patent Document 1). In addition, as a similar intake device, the operation of the flow control valve and the operation of the EGR valve so that the opening of the EGR valve is throttled in accordance with the increase of the opening of the flow control valve provided in one of the two flow paths. Is known (Patent Document 2).

JP 2002-106419 A JP-A-2-185653

  In the intake devices of these documents, when the flow control valve is in a closed state, burned gas blown back from the cylinder side may stay in the flow path provided with the flow control valve. For this reason, when the flow control valve shifts from the closed state to the open state while the burnt gas that can be regarded as exhaust gas remains, the burned gas and the exhaust gas that passes through the EGR gas passage are introduced into the cylinder together. Therefore, the substantial EGR amount may temporarily become excessive. In the intake device of Patent Document 2, the opening degree of the EGR valve is reduced according to the increase in the opening degree of the flow control valve, but the opening degree of the EGR valve is only reduced in the state where the flow control valve is opened. Such a temporary excess of the EGR amount cannot be sufficiently suppressed.

  Therefore, an object of the present invention is to provide an intake device for an internal combustion engine that can suppress an excessive amount of EGR when the flow rate control valve shifts from the closed state to the open state.

  An intake system for an internal combustion engine according to the present invention is applied to an internal combustion engine provided with an EGR passage that recirculates a part of exhaust gas to an intake passage and an EGR valve that is provided in the EGR passage and is adjustable in opening. In an engine intake device, a partition member that divides the intake passage into at least two flow paths, a flow rate control valve that is provided in one of the two flow paths and can be adjusted in opening, and the flow rate In the process in which the control valve shifts from the closed state to the open state, the EGR valve is controlled so that the recirculation amount of the exhaust gas that has passed through the EGR passage decreases prior to the completion of the transition of the flow rate control valve to the open state. The above-described problem is solved by providing control means for controlling to the closed side (Claim 1).

  According to this intake device, the exhaust gas recirculation amount is reduced prior to the completion of the transition of the flow control valve to the open state in the process of transition of the flow control valve from the closed state to the open state. Therefore, even when the burned gas staying in the flow path is released by the flow control valve, the corresponding amount of the burned gas staying in the flow path is offset by the decrease in the recirculation amount of the exhaust gas passing through the EGR passage. Thereby, it is possible to suppress a substantial excess of the EGR amount guided into the cylinder.

  In one aspect of the intake device of the present invention, the control means includes a valve opening mode for controlling the EGR valve so as to obtain an opening degree corresponding to a valve opening state of the flow control valve, and a closing of the flow control valve. And selectively executing a valve closing mode for controlling the EGR valve so as to obtain an opening corresponding to the valve state, and in the process of the flow control valve shifting from the valve closing state to the valve opening state, While switching from the mode to the valve opening mode, the EGR valve may be controlled to the closed side so that the recirculation amount of the exhaust gas passing through the EGR passage decreases. Since the flow field in the intake passage changes when the state of the flow control valve changes, the change affects the amount of exhaust gas recirculated via the EGR passage. According to this aspect, since the control mode corresponding to the state of the flow control valve is selectively executed, stable exhaust gas recirculation to the intake passage can be realized. Since the flow rate of the exhaust flow through the EGR passage decreases while the flow rate control valve switches from the closed mode to the open mode with the transition from the closed state to the open state, the flow control valve is led into the cylinder. Excessive EGR amount can be suppressed.

  When the EGR valve is controlled to be closed, the control means may throttle the opening of the EGR valve as the intake air flow rate increases. According to this aspect, since the flow rate of the burned gas staying in the flow path increases as the intake air flow rate increases, the recirculation amount of the exhaust gas via the EGR passage can be reduced as much as the increase amount. Thereby, excess of the EGR amount can be more reliably suppressed.

  Although the connection position of the EGR passage to the intake passage is arbitrary, for example, the EGR passage may be connected to one of the two flow paths (Claim 4). When a flow control valve is provided for one flow rate and an EGR passage is connected to the other flow channel, the burned gas that has accumulated in one flow channel when the flow control valve shifts from the closed state to the open state. Since the gas and the exhaust gas passing through the EGR passage are guided into the cylinder without time difference, the EGR amount tends to be excessive. According to this aspect, since the excess of the EGR amount can be effectively suppressed, a highly practical intake device can be provided.

  In this aspect, the control means includes an opening mode for controlling the EGR valve so as to obtain an opening corresponding to the opened state of the flow control valve, and an open state corresponding to the closed state of the flow control valve. A valve closing mode for controlling the EGR valve so as to obtain a degree of pressure, and in a process in which the flow control valve shifts from a valve opening state to a valve closing state, Prior to the completion of the transition to, the valve opening mode may be switched to the valve closing mode (Claim 5). When the flow rate control valve is in the closed state, the flow velocity and pulsation of the other flow path increase as compared to the open state. Therefore, when the flow rate control valve is in the open state and the closed state, and the EGR valve is set to the same opening degree and the exhaust gas recirculation amount is compared, the recirculation amount of the exhaust gas when the flow control valve is in the closed state. Becomes larger than when the flow control valve is in the open state. Therefore, when the flow rate control valve is switched from the valve opening mode to the valve closing mode at the same time or after the transition to the valve closing state, the EGR amount may temporarily become excessive at the time of switching. According to this embodiment, since the valve opening mode is switched to the valve closing mode prior to the completion of the transition of the flow control valve to the closed state, the operation of the flow control valve is delayed with respect to the operation of the EGR valve. Thereby, such temporary excess of the EGR amount can be suppressed.

  As described above, according to the present invention, the exhaust gas recirculation amount is reduced prior to the completion of the transition of the flow control valve to the open state in the process of transition of the flow control valve from the closed state to the open state. The Therefore, even when the burned gas staying in the flow path is released by the flow control valve, the corresponding amount of the burned gas staying in the flow path is offset by the decrease in the recirculation amount of the exhaust gas passing through the EGR passage. Thereby, it is possible to suppress a substantial excess of the EGR amount guided into the cylinder.

  FIG. 1 shows a main part of an internal combustion engine to which an intake device according to an embodiment of the present invention is applied. The internal combustion engine 1 is mounted as a driving power source for an automobile and is configured as an in-cylinder direct injection internal combustion engine that directly injects fuel into the cylinder 2. Although the internal combustion engine 1 has a plurality of cylinders 2, only one cylinder 2 is shown in the figure for convenience.

  The cylinder 2 is formed in the cylinder block 3, and the opening of the cylinder 2 is closed by the cylinder head 4. A piston 5 is inserted into the cylinder 2 so as to freely reciprocate, and a combustion chamber 6 is formed above the piston 5. The cylinder head 4 is provided with a spark plug 7 so that its tip faces the center of the ceiling surface of the cylinder 2. A fuel injection valve 8 is attached to the cylinder head 4 such that the tip of the cylinder head 4 faces the corner of the ceiling surface of the cylinder 2.

  The internal combustion engine 1 includes an intake passage 10 for taking intake air into the cylinder 2 and an exhaust passage 11 for guiding exhaust from the cylinder 2. The intake passage 10 has a branch portion (not shown) that branches for each cylinder 2 and an intake port 12 that follows the branch portion. The intake port 12 is formed in the cylinder head 4 and opens on the ceiling surface of the cylinder 2. The exhaust passage 11 includes an exhaust port 13 that is formed in the cylinder head 4 and opens to the ceiling surface of the cylinder 2.

  An intake valve 15 that opens and closes the intake port 12 is slidably attached to the cylinder head 4, and an exhaust valve 16 that opens and closes the exhaust port 13 is also slidably attached to the cylinder head 4. Yes. Each of the intake valve 15 and the exhaust valve 16 is driven to open / close by a valve mechanism (not shown) according to a predetermined opening / closing timing.

  The intake port 12 is divided into two flow paths 12A and 12B by a partition wall 17 as a partition member. The partition wall 17 extends in the flow direction of the intake port 12, and the flow paths 12 </ b> A and 12 </ b> B divided by the partition wall 17 are arranged vertically in the center line direction of the cylinder 2. Further, a tumble control valve (TCV) 18 as a flow control valve whose opening degree can be adjusted is provided in the upper flow path 12A in order to change the flow ratio of the flow paths 12A and 12B. The TCV 18 is rotatably attached to the upstream end of the flow path 12A. The TCV 18 is provided with a drive device (not shown) that can freely hold the opening degree from the fully closed position indicated by the solid line to the fully open position indicated by the imaginary line. By appropriately operating the drive device to change the opening of the TCV 18, the flow rate ratio between the flow rate of the flow channel 12A and the flow rate of the flow channel 12B can be changed within a range of 1: 1 to 0: 1. . For example, by setting the opening of the TCV 18 to the closed side and biasing the flow velocity distribution in the intake port 12 downward, it is possible to generate the tumble Ft that is the intake flow swirling in the cylinder 2 in the vertical direction. . Further, the strength of the tumble Ft can be adjusted by appropriately setting the opening on the closing side.

  The internal combustion engine 1 is provided with an EGR device 20 that recirculates the exhaust gas extracted from the exhaust passage 11 to the intake passage 10 in order to lower the combustion temperature in the cylinder 2 and reduce the emission amount of nitrogen oxides. The EGR device 20 includes an EGR passage 21 connecting the exhaust passage 11 and the intake passage 10 and an EGR valve 22 provided in the EGR passage 21 and having an adjustable opening. The EGR passage 21 has a branch portion 21a for distributing a part of the exhaust gas taken out from the exhaust passage 11 to each intake port 12, and the branch portion 21a is connected to a flow path 12B below the intake port 12. Has been. As a result, a part of the exhaust G1 is introduced into the lower flow path 12B as shown by the arrow line in FIG.

  The respective opening degrees of the TCV 18 and the EGR valve 22 are controlled by an engine control unit (ECU) 25 configured as a computer that controls the operating state of the internal combustion engine 1. The ECU 25 controls the injection timing of the fuel injection valve 8 and the ignition timing of the spark plug 7 according to a predetermined program while referring to information from various sensors. Hereinafter, the control performed by the ECU 25 will be described by limiting to the control related to the present invention.

  The opening degree control of the TCV 18 is performed so that the tumble Ft is formed according to the rotational speed and load of the internal combustion engine 1. In the case of this embodiment, the TCV 18 is not held at the intermediate opening of the TCV 18 and the TCV 18 is operated so as to switch between a valve closing state in which the upper flow path 12A is fully closed and a valve opening state in which the flow path 12A is fully opened. I try to let them. When the state of the TCV 18 changes between the valve closing state and the valve opening state, the flow field in the intake passage 10 changes, so that the change affects the amount of exhaust gas recirculated via the EGR passage 21.

  Therefore, the ECU 25 opens the EGR valve 22 so that the opening degree corresponding to the valve opening state of the TCV 18 is obtained, and the valve opening mode for controlling the EGR valve 22 so as to obtain the opening degree corresponding to the valve opening state of the TCV 18. The valve closing mode to be controlled is selectively executed. In these control modes, the ECU 25 refers to an opening map that associates the target opening of the EGR valve 22 with the operation parameters such as the rotation speed and load of the internal combustion engine 1, so that it corresponds to the actual operation parameter value. The target opening is calculated and the EGR valve 22 is controlled so that the target opening can be realized. An opening degree map is prepared for each control mode, and the ECU 25 selectively switches the opening degree map as the state of the TCV 18 is changed. This embodiment is characterized by the control of the EGR valve 22 linked to the operation of the TCV 18 in a transient state in which the state of the TCV 18 is switched between the valve open state and the valve closed state.

  FIG. 2 is a timing chart showing an example of a control result according to this embodiment. In this timing chart, the TCV 18 operation request, the TCV 18 operation permission flag, the TCV 18 operation state, and the time variation of the target opening of the EGR valve 22 are shown on the same time axis. The operation request for the TCV 18 is issued in accordance with the operating state of the internal combustion engine 1. The operation request includes an opening request for shifting the TCV 18 from the valve closing state to the valve opening state, and from the valve opening state to the valve closing state. And a close request to be transferred. The operation permission flag of the TCV 18 is a variable that is set to a predetermined value when an operation permission condition that satisfies the requirement that an operation request is issued is satisfied, and is cleared when the condition is not satisfied. The operation permission flag is assigned to a predetermined storage area of the ECU 25. The TCV 18 is actually operated when the permission flag is set.

  As shown in FIG. 2, since the TCV 18 is in the closed state at time t0, the target opening degree of the EGR valve 22 is calculated based on the opening degree map for the closed state. That is, the ECU 25 selects the valve closing mode as the control mode of the EGR valve 22. When the TCV 18 is in a closed state, as shown in FIG. 1, the upper flow path 12A is closed on the upstream side, so that the burned gas G2 that can be regarded as exhaust blown back from the cylinder 2 side flows on the downstream side of the TCV 18. It will be in the state which stayed in the path 12A.

  Returning to FIG. 2, when a request to open the TCV 18 is issued at time t1, the operation permission flag is set immediately, and the target opening of the EGR valve 18 is set to the predetermined opening α on the closing side in response to the setting of the operation permission flag. Be changed. The predetermined opening degree α may be a fixed value (for example, an opening degree of 0% in a fully closed state), or may be a variable value that changes in accordance with the intake flow rate so that the opening degree of the EGR valve 22 is reduced as the intake flow rate increases. . The target opening degree of the EGR valve 18 is maintained at the predetermined opening degree α for a predetermined time Δt1 until the TCV 18 is completely shifted to the valve opening state. After the elapse of the predetermined time Δt1, the opening degree map for calculating the target opening degree of the EGR valve 22 is switched to the opening degree opening degree map. That is, the EGR valve 22 is controlled to the predetermined opening degree α on the closing side while the control mode is switched from the valve closing mode to the valve opening mode. In parallel with such control of the EGR valve 18, the TCV 18 is operated to shift from the valve closing state to the valve opening state in response to the setting of the operation permission flag. With this operation, the burned gas G2 (FIG. 1) staying downstream of the TCV 18 is released and starts flowing toward the downstream indicated by the arrow in FIG.

  As described above, in the process of the TCV 18 shifting from the valve closing state to the valve opening state, the opening degree of the EGR valve 18 is controlled to the predetermined opening degree α on the closing side prior to completion of the transition of the TCV 18 to the valve opening state. The recirculation amount of the exhaust gas that has passed through the EGR passage 21 decreases before the TCV 18 shifts to the valve open state. Therefore, even when the burned gas G2 staying in the flow path 12A is released by the TCV 18, a considerable amount of the burned gas G2 staying in the flow path 12A is reduced due to a decrease in the recirculation amount of the exhaust gas passing through the EGR passage 21. Offset. Accordingly, it is possible to suppress an excessive excess of the EGR amount guided into the cylinder 2.

  At time t2, since the TCV 18 is in the valve opening state, the target opening degree of the EGR valve 22 is calculated based on the opening degree opening degree map. That is, the ECU 25 selects the valve opening mode as the control mode of the EGR valve 22.

  Thereafter, when a request for closing the TCV 18 is issued at time t3, the control mode of the EGR valve 22 is switched from the valve opening mode to the valve closing mode while the TCV 18 is maintained in the valve opening state. The operation permission flag is set when a predetermined time Δt2 has elapsed since the control mode was switched, and the TCV 18 is operated so as to shift from the open state to the closed state in response to the setting. That is, in the process in which the TCV 18 transitions from the valve opening state to the valve closing state, the control mode of the EGR valve 22 is switched from the valve opening mode to the valve closing mode prior to completion of the transition of the TCV 18 to the valve closing state.

  As shown in FIG. 1, when the TCV 18 is in the valve closing state, the flow velocity and pulsation of the lower flow path 12B increase as compared with the valve opening state. Therefore, if the control mode of the EGR valve 22 is switched from the valve opening mode to the valve closing mode at the same time or after the TCV 18 shifts from the valve opening state to the valve closing state, the EGR amount is temporarily changed during the switching. May be excessive. In this embodiment, since the control mode of the EGR valve 22 is switched from the valve opening mode to the valve closing mode prior to the completion of the transition of the TCV 18 to the valve closing state, the operation of the TCV 18 is delayed with respect to the operation of the EGR valve 22. . Thereby, such temporary excess of the EGR amount can be suppressed.

  In order to realize the control shown in FIG. 2, the ECU 25 of the present embodiment executes the control routine of FIG. FIG. 3 is a flowchart showing an example of a control routine according to this embodiment. A program for this routine is held in the ECU 25, read out in a timely manner, and repeatedly executed at predetermined intervals.

  As shown in the figure, in step S1, it is determined whether or not the TCV 18 is in a closed state. The determination is made based on an output signal from the opening sensor 26 that outputs a signal corresponding to the opening of the TCV 18. When the TCV 18 is in the closed state, the process proceeds to step S2, and when not, that is, when the TCV 18 is in the opened state, the process proceeds to step S9.

  In step S2, the valve closing mode is selected as the control mode of the EGR valve 22. That is, the target opening of the EGR valve 22 is calculated based on the opening map for the closed state, and the EGR valve 22 is controlled so that the target opening is obtained.

  In step S3, it is determined whether or not there is an open request for the TCV 18. If there is an open request, the process proceeds to step S4, and if not, the subsequent process is skipped in order to maintain the valve closing mode, and the current routine is terminated.

  In step S4, an operation permission flag for permitting the TCV 18 to shift from the valve closing state to the valve opening state is set. In response to the setting of the operation permission flag, the TCV 18 is operated so as to shift from the valve closing state to the valve opening state by an opening degree control routine (not shown) of the TCV 18 executed in parallel with the routine of FIG. The

  In step S5, the closing side control for maintaining the opening degree of the EGR valve 22 at a predetermined opening degree α on the closing side is started.

  In step S6, it is determined whether or not a predetermined time Δt1 has elapsed since the opening of the TCV 18 has been approved, that is, since the operation permission flag has been set, and the processing is suspended until the predetermined time Δt1 has elapsed. That is, the closing side control for the EGR valve 22 is continued.

  If the predetermined time Δt1 has elapsed, the process proceeds to step S7, and the closing side control of the EGR valve 22 started in step S5 is terminated. In this embodiment, the closing side control of the EGR valve 22 is completed before the transition to the valve opening state is completed in consideration of the delay time from when the operation permission flag of the TCV 18 is output until the transition to the valve opening state of the TCV 18 is completed. Is set to a predetermined time Δt1 (see FIG. 2).

  In step S8, the control mode of the EGR valve 22 is switched to the valve opening mode. That is, the valve opening mode is selected as the control mode, and the target opening degree of the EGR valve 22 is calculated based on the opening degree opening degree map. Then, the EGR valve 22 is controlled so that the target opening degree is realized. Thereafter, the current routine is terminated.

  In step S9, since the TCV 18 is in the valve opening state, the valve opening mode is selected as the control mode of the EGR valve 22. That is, the target opening degree of the EGR valve 22 is calculated based on the opening degree opening degree map, and the EGR valve 22 is controlled so as to obtain the target opening degree.

  In step S10, it is determined whether or not there is a close request for the TCV 18. If there is a closing request, the process proceeds to step S11. If not, the subsequent routine is terminated by skipping the subsequent processing to maintain the valve opening mode.

  In step S11, the control mode of the EGR valve 22 is switched to the valve closing mode. That is, the valve closing mode is selected as the control mode, the target opening degree of the EGR valve 22 is calculated based on the opening degree map for the valve closing state, and the EGR valve 22 is controlled so that the target opening degree is realized. .

  In step S12, it is determined whether or not a predetermined time Δt2 has elapsed since the switching of the control mode, and the process is suspended until the predetermined time Δt2 has elapsed.

  When the predetermined time Δt2 has elapsed, the process proceeds to step S13, and an operation permission flag for permitting the TCV 18 to shift from the valve open state to the valve close state is set. In response to the setting of the operation permission flag, the TCV 18 is operated so as to shift from the valve open state to the valve closed state by an opening degree control routine (not shown) of the TCV 18 executed in parallel with the routine of FIG. The Thereafter, the current routine is terminated.

  According to the above routine, the opening degree of the EGR valve 18 is controlled to the predetermined opening degree T on the closing side prior to the completion of the transition of the TCV 18 to the valve opening state in the process of the TCV 18 shifting from the valve closing state to the valve opening state. At the same time, the control mode of the EGR valve 22 is switched from the valve opening mode to the valve closing mode prior to the completion of the transition of the TCV 18 to the valve closing state in the process of the TCV 18 shifting from the valve opening state to the valve closing state. Thereby, the effect demonstrated in FIG. 2 can be acquired. And when ECU25 performs the routine of FIG. 3, ECU25 functions as a control means which concerns on this invention.

  This invention is not limited to the form mentioned above, It can implement with a various form. The internal combustion engine to which the intake device of the present invention can be applied is not limited to the direct injection type internal combustion engine. The present invention can also be applied to a port injection type internal combustion engine that injects fuel into the intake passage.

  In the illustrated form, the EGR passage 21 is connected to the lower flow path 12B partitioned by the partition wall 17, but is not limited to the connection position, and the EGR passage 21 is connected to an arbitrary place in the intake passage 10. May be. For example, the present invention can be implemented in a form in which the EGR passage 21 is connected to the intake passage 10 on the upstream side of the TCV 18.

  The TCV 18 is only an example of a flow control valve. For example, the present invention may be implemented in a form in which a swirl control valve that forms a swirl that turns in a circumferential direction is provided as a flow control valve. Further, the flow control valve may not be configured as a butterfly valve like the TCV 18. For example, as shown in FIG. 4, a flap that is arranged in a rotatable state around a rotation axis Ax set at the upstream end of the partition wall 17 and opens or closes one of the two flow paths 12A and 12B. It is also possible to implement the present invention in a form in which 30 is provided as a flow control valve.

  In the above-described form, the control mode of the EGR valve is switched between the valve opening mode and the valve closing mode in accordance with the state of the flow control valve. However, as long as the above-described closing side control is performed on the EGR valve, the closing operation is performed. In an area where side control is not performed, the EGR valve may be controlled in a single control mode.

The figure which showed the principal part of the internal combustion engine to which the intake device which concerns on one form of this invention was applied. The timing chart which showed an example of the control result. The flowchart which shows an example of a control routine. Explanatory drawing explaining the other form of a flow control valve.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 10 Intake passage 12A, 12B Flow path 17 Partition (partition member)
18 TCV (Flow control valve)
21 EGR passage 22 EGR valve 25 ECU (control means)
30 flaps (flow control valve)

Claims (5)

In an internal combustion engine intake system applied to an internal combustion engine provided with an EGR passage that recirculates a part of exhaust gas to an intake passage and an EGR valve that is provided in the EGR passage and can be adjusted in opening degree.
A partition member that divides the intake passage into at least two flow paths, a flow rate control valve that is provided in one of the two flow paths and can be adjusted in opening, and the flow rate control valve is in a closed state Control for controlling the EGR valve to the closed side so that the recirculation amount of the exhaust gas passing through the EGR passage is reduced prior to completion of the transition of the flow rate control valve to the valve open state in the process of transition from the valve to the valve open state. And an intake device for an internal combustion engine.   The control means obtains a valve opening mode for controlling the EGR valve so as to obtain an opening corresponding to the open state of the flow control valve, and an opening corresponding to the closed state of the flow control valve. The valve closing mode for controlling the EGR valve is selectively executed and the flow rate control valve is switched from the valve closing mode to the valve opening mode in the process of shifting from the valve closing state to the valve opening state. The intake device according to claim 1, wherein the EGR valve is controlled to be closed so that a recirculation amount of the exhaust gas that has passed through the EGR passage decreases.   3. The intake device according to claim 1, wherein when the control means controls the EGR valve to the closed side, the opening degree of the EGR valve is reduced as the intake flow rate increases.   The intake device according to claim 1, wherein the EGR passage is connected to one of the two flow paths.   The control means obtains a valve opening mode for controlling the EGR valve so as to obtain an opening corresponding to the open state of the flow control valve, and an opening corresponding to the closed state of the flow control valve. The valve closing mode for controlling the EGR valve is selectively executed, and the transition of the flow control valve to the closed state is completed in the process of the flow control valve shifting from the open state to the closed state. The intake device according to claim 4, wherein the valve opening mode is switched to the valve closing mode prior to the valve opening mode.

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