JP2010196524A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for an internal combustion engine appropriately controlling the amount of exhaust gas recirculated. <P>SOLUTION: This control device for the internal combustion engine includes: a first throttle valve 14 arranged in an intake passage 11 and regulating to intake air volume according to a required load; a supercharger 30 provided in the intake passage and supercharging intake air; an exhaust gas recirculation means 40 having a recirculation passage 41 recirculating a part of exhaust gas in an exhaust passage 21 to the upstream side of the supercharger in the intake passage, and a recirculation valve 42 opening/closing the recirculation passage; a recirculation passage 70 for allowing the downstream side of the supercharger in the intake passage to communicate with the upstream side thereof; and a recirculation valve 71 opening/closing the recirculation passage. In the control device, a control means 50 is provided for outputting a control signal only for a predetermined time in order to open the recirculation valve 42 and recirculation valve 71 when transferring from an operating condition that the exhaust gas recirculation means is operated to an operating condition that the exhaust gas recirculation means is not operated. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a control device for an internal combustion engine in which exhaust gas recirculation (EGR) is applied to an engine with a supercharger.

As one in which exhaust gas recirculation is applied to an engine with a supercharger, there is known one that recirculates exhaust gas downstream of a catalytic converter to an intake system upstream of a supercharger (Patent Document 1).

In this engine, exhaust gas is recirculated upstream of the turbocharger before the intake air is pressurized, so that a large amount of recirculated gas can be stabilized even in the high-load operation region where the supercharging pressure increases. There is an advantage that the combustion temperature can be suppressed in the high load side operation region.

JP-A-5-296095

  However, in the configuration in which the exhaust gas is recirculated to the intake system upstream of the turbocharger, for example, when the throttle valve shifts to the closed state in response to the driver's intention to decelerate the accelerator, the throttle valve Since the exhaust gas recirculated is pushed in by the supercharger while the engine is closed, a large amount of exhaust gas remains in the intake system.

  The remaining exhaust gas amount varies depending on the operating conditions and cannot be accurately grasped. Therefore, it remains when the throttle valve is opened for re-acceleration or when idling is started. Since the exhaust gas is supplied to the cylinder, there is a problem that the amount of the recirculated exhaust gas cannot be accurately controlled.

The problem to be solved by the present invention is that, in a system that recirculates exhaust gas in the intake passage upstream of the turbocharger, the amount of exhaust gas to be recirculated is appropriate even during reacceleration or when idle operation is resumed. It is providing the control apparatus of the internal combustion engine which can be controlled easily.

The present invention provides a supercharger for supercharging intake air, an exhaust gas recirculation means having a recirculation valve for recirculating a part of exhaust gas to an intake passage upstream of the supercharger, Recirculation for a predetermined time when the exhaust gas recirculation means stops from the operating state in a system including a recirculation passage communicating the downstream side and the upstream side of the turbocharger and a recirculation valve for opening and closing the recirculation passage. The valve and the reflux valve are controlled to be opened.

  As a result, the throttle valve is normally closed, so that the recirculated exhaust gas is pushed in by the supercharger and remains in a large amount between the throttle valve and the supercharger. Since the valve and the recirculation valve are controlled to open, the exhaust gas remaining in the intake passage is removed from the recirculation passage through the recirculation passage. Further, since there is no influence of the remaining exhaust gas at the time of reacceleration or when the idle operation is resumed, the amount of exhaust gas corresponding to the operation state at that time can be appropriately controlled at the time of reacceleration or when the idle operation is resumed.

1 is a block diagram showing a control device for an internal combustion engine to which an embodiment of the present invention is applied. It is a perspective view which shows the variable valve mechanism of the intake valve of the internal combustion engine of FIG. It is a characteristic view which shows the phase change of the valve lift characteristic by the phase variable mechanism of the variable valve mechanism of FIG. FIG. 3 is a cross-sectional view showing a lift / operating angle variable mechanism of the variable valve mechanism in FIG. 2. FIG. 3 is a characteristic diagram showing a change in lift / operation angle characteristics by the variable lift / operation angle mechanism of the variable valve mechanism of FIG. It is a flowchart which shows the control procedure by the control apparatus of FIG. 2 is a region map showing EGR control by the control device of FIG. 1. It is a timing chart which shows the control by the control apparatus of FIG.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments in the case where the present invention is applied to a control device for an internal combustion engine will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing a control apparatus for an internal combustion engine to which an embodiment of the present invention is applied. In an intake passage 11 of the internal combustion engine 1, an air filter 12, an air flow meter 13 for detecting an intake air flow rate, A first throttle valve 14, a second throttle valve 72, a pressure sensor 73, and a collector 15 that control the intake air flow rate are provided.

  The first throttle valve 14 is provided with a throttle sensor that detects the opening degree of the throttle valve 14 and a throttle valve control device that can control the opening degree of the first throttle valve 14 by an actuator such as a DC motor. ing. This throttle valve control device electronically controls the opening degree of the first throttle valve 14 based on a drive signal from the control unit 50 so as to achieve a required torque calculated based on a driver's accelerator pedal operation amount or the like. .

On the other hand, the second throttle valve 72 provided downstream of the air flow meter 13 in the intake passage 11 is a valve that mainly adjusts the recirculation amount by the exhaust gas recirculation mechanism 40, and is a supercharging region B1 shown in FIG. , B2 and C, by restricting the second throttle valve 72, a differential pressure is provided between the pressure of the intake passage 11 between the second throttle valve 72 and the compressor wheel 34 and the exhaust passage 21, whereby the exhaust passage 21 Control the amount of exhaust gas recirculation.

The second throttle valve 72 also has a function of preventing fuel components contained in the exhaust gas from adhering to the air flow meter 13. The opening degree of the second throttle valve 72 is electronically controlled based on a drive signal from the control unit 50.

The pressure sensor 73 detects the pressure in the intake passage 11 between the second throttle valve 72 and the compressor wheel 34 and outputs the detection signal to the control unit 50. The pressure detected by the pressure sensor 73 is used to determine the end timing of the residual gas purge process.

  A fuel injection valve 17 is provided facing the combustion chamber 16 of each cylinder of the internal combustion engine 1. The fuel injection valve 17 is driven to open by a drive pulse signal set in the control unit 50, and pressure is supplied from a fuel pump (not shown) and is controlled to a predetermined pressure by a pressure regulator (not shown). Inject directly into.

  The spark plug 20 is mounted facing the combustion chamber 16 of each cylinder, and ignites the intake air-fuel mixture based on an ignition signal from the control unit 50.

  On the other hand, the exhaust passage 21 is provided with an exhaust purification catalyst 24 for purifying the exhaust. The exhaust purification catalyst 24 oxidizes carbon monoxide CO and hydrocarbon HC in the exhaust in the vicinity of stoichiometric (theoretical air-fuel ratio, λ = 1, air weight / fuel weight = 14.7), and nitrogen oxide NOx. It is possible to use a three-way catalyst that can purify the exhaust gas by reducing the above, or an oxidation catalyst that oxidizes carbon monoxide CO and hydrocarbon HC in the exhaust gas.

  Further, an exhaust pressure sensor 25 that detects the pressure of the exhaust gas is provided on the downstream side of the exhaust purification catalyst 24 in the exhaust passage 21, and the detection signal is output to the control unit 50. The pressure detected by the exhaust pressure sensor 25 is used together with the pressure detected by the pressure sensor 73 to determine the end timing of the residual gas purging process.

  In FIG. 1, reference numeral 23 denotes a muffler.

  The internal combustion engine 1 of the present embodiment is an engine having a supercharger 30, and the supercharger 30 shown in the figure is directly connected to the turbine wheel via a turbine wheel 32 provided in the exhaust passage 21 and a rotor shaft 33. The compressor wheel 34 is provided, the turbine wheel 32 is rotated by the exhaust gas, and the intake air is compressed by the rotating compressor wheel 34 and sent to the collector 15.

  On the turbine side of the turbocharger 30, a bypass circuit 35 is provided in which part or all of the exhaust gas from the combustion chamber 16 bypasses the turbine wheel 32 and reaches the exhaust purification catalyst 24, and passes through the bypass circuit 35. A waste gate valve 31 for controlling the amount of exhaust gas is provided in the bypass 35. The waste gate valve 31 performs opening / closing control so as to release part or all of the exhaust gas to the detour 35 side so as to reach the target boost pressure according to the operating state of the engine.

  An intercooler 36 for cooling the intake air compressed by the compressor of the supercharger 30 and cooled to high temperature is provided between the downstream of the supercharger 30 (compressor side) in the intake passage 11 and the throttle valve 14. . The intercooler 36 can be either air-cooled or water-cooled.

  A recirculation passage 70 that bypasses the intercooler 36 is provided between the intake passage 11 upstream of the compressor wheel 34 and the intercooler 36, and a recirculation valve 71 is provided in the recirculation passage 70. The reflux valve 71 opens and closes the reflux passage 70 based on a drive signal from the control unit 50. This will be described later.

  The internal combustion engine 1 of the present embodiment includes an exhaust gas recirculation mechanism 40 that recirculates exhaust gas downstream of the exhaust purification catalyst 24 to the intake passage 11 upstream of the supercharger 30, and has predetermined operating conditions (for example, In the high load region), since the exhaust gas is recirculated upstream of the supercharger 30 before the intake air is pressurized, a large amount of recirculated gas is supplied to the intake passage 11 even when the supercharging pressure is high. Can be introduced stably. As a result, the exhaust gas temperature can be lowered and the fuel consumption can be improved.

  On the other hand, although details will be described later, the exhaust gas recirculation mechanism 40 is stopped and exhausted into the combustion chamber 16 by the overlap control of the intake and exhaust valves described later, except for the predetermined operating conditions (for example, in a low load region). Emission is reduced by performing so-called internal EGR that causes gas to remain, and reoxidizing unburned HC contained in the remaining high-temperature exhaust gas.

  The exhaust gas recirculation mechanism 40 of this example is provided in the recirculation passage 41, which connects the exhaust passage 21 downstream of the exhaust purification catalyst 24 and the intake passage 11 upstream of the supercharger 30, and the recirculation passage 41. And a recirculation valve 42 that opens and closes to adjust the flow rate of the recirculated exhaust gas. The opening / closing operation of the recirculation valve 42 is controlled by a control signal from the control unit 50.

  Further, a refrigerant for cooling the exhaust gas to be recirculated is circulated as shown by an arrow 43, and the exhaust gas cooled by exchanging heat with the exhaust gas is recirculated to the intake passage 11.

  The internal combustion engine 1 of the present embodiment is an engine including a variable valve mechanism 60 that can change the overlap of intake and exhaust valves, and an example of the variable valve mechanism 60 will be described with reference to FIGS.

  FIG. 2 is a perspective view showing an example of the intake valve side variable valve mechanism 60 of the internal combustion engine 1. The variable valve mechanism 60 of the present example is a lift that changes the lift and operating angle of an intake valve (not shown). The operating angle variable mechanism 61 is combined with a phase variable mechanism 62 that advances or retards the phase of the lift center angle (phase relative to the crankshaft).

  As shown in the figure, the phase variable mechanism 62 includes a sprocket 622 provided at the front end of the drive shaft 621, and a phase control that relatively rotates the sprocket 622 and the drive shaft 621 within a predetermined angle range. And a hydraulic actuator 624 for use.

  The sprocket 623 is linked to the driving of the crankshaft via a timing chain or a timing belt (not shown). The hydraulic pressure supply to the phase control hydraulic actuator 624 is controlled based on a control signal from the control unit 50.

  By this hydraulic control to the phase control hydraulic actuator 624, the sprocket 623 and the drive shaft 621 rotate relatively, and the lift center angle is retarded as shown in FIG. FIG. 3 is a characteristic diagram showing a phase change of the valve lift characteristic by the phase variable mechanism 62. That is, the lift characteristic curve itself does not change, and the whole advances or retards. This change can be obtained continuously.

  The phase variable mechanism 62 is not limited to the hydraulic type shown in the figure, and various configurations such as those using an electromagnetic actuator are possible.

  Next, FIG. 4 is a cross-sectional view showing only the lift / operating angle variable mechanism 61, and an outline of the lift / operating angle variable mechanism 61 will be described based on FIGS. 2 and 4.

  The lift / operating angle varying mechanism 61 of this example is rotatably supported by a cam bracket 163 above the cylinder head 161 with respect to an intake valve 162 slidably provided on the cylinder head 161 via a valve guide (not shown). A hollow drive shaft 621, an eccentric cam 611 fixed to the drive shaft 621 by press-fitting or the like, and a cam bracket 163 that is rotatably supported above the drive shaft 621 and parallel to the drive shaft 621. , A rocker arm 613 swingably supported by an eccentric cam portion 612a of the control shaft 612, and a swing cam 614 that abuts a tappet 164 disposed at the upper end of each intake valve 162. And comprising.

  The eccentric cam 611 and the rocker arm 613 are connected by a link arm 615, and the rocker arm 613 and the swing cam 614 are connected by a link member 616.

  The drive shaft 621 is driven by the engine crankshaft via the timing chain or timing belt as described above.

  The eccentric cam 611 has a circular outer peripheral surface, the center of the outer peripheral surface is offset by a predetermined amount from the axis of the drive shaft 621, and the annular portion 615a of the link arm 615 is rotatable on the outer peripheral surface. It is mated.

  The rocker arm 613 is supported at an approximately central portion by an eccentric cam portion 612a. An extension portion 615b of the link arm 615 is connected to one end portion thereof, and an upper end portion of the link member 616 is connected to the other end portion thereof. The eccentric cam portion 612a is eccentric from the axis of the control shaft 612. Therefore, the rocking center of the rocker arm 613 changes depending on the angular position of the control shaft 612.

  The swing cam 614 is rotatably supported by being fitted to the outer periphery of the drive shaft 621, and a lower end portion of the link member 616 is connected to an end portion 614 a extending sideways. On the lower surface of the swing cam 614, a base circle surface 617a that forms a concentric arc with the drive shaft 621, a cam surface 617b extending from the base circle surface 617a to the end 614a in a predetermined curve, The base circle surface 617a and the cam surface 617b are in contact with the upper surface of the tappet 164 according to the swing position of the swing cam 614.

  That is, the base circle surface 617a is a section where the lift amount becomes 0 as a base circle section, and when the swing cam 614 swings and the cam surface 617b contacts the tappet 164, it gradually lifts. . A slight ramp section is provided between the base circle section and the lift section.

  As shown in FIG. 2, the control shaft 612 is configured to rotate within a predetermined rotation angle range by a lift / operation angle control hydraulic actuator 618 provided at one end. The hydraulic pressure supply to the lift / operating angle control hydraulic actuator 618 is controlled based on a control signal from the control unit 50. The actuator 618 is configured to urge the intake valve 162 to the small lift / small operating angle side under the condition that the drive power of the actuator 618 is OFF.

  The operation of the lift / operation angle varying mechanism 61 of this example will be described. When the drive shaft 621 rotates, the link arm 615 moves up and down by the cam action of the eccentric cam 611, and the rocker arm 613 swings accordingly. The swing of the rocker arm 613 is transmitted to the swing cam 614 via the link member 616, and the swing cam 614 swings. The tappet 164 is pressed by the cam action of the swing cam 614, and the intake valve 162 is lifted.

  Here, when the angle of the control shaft 612 changes via the lift / operating angle control hydraulic actuator 618, the initial position of the rocker arm 613 changes, and consequently the initial swing position of the swing cam 614 changes.

  For example, if the eccentric cam portion 612a is positioned upward in the drawing, the rocker arm 613 is positioned upward as a whole, and the end 614a of the swing cam 614 is relatively lifted upward. That is, the initial position of the swing cam 614 is inclined in a direction in which the cam surface 617 b is separated from the tappet 164. Therefore, when the swing cam 614 swings with the rotation of the drive shaft 621, the base circle surface 617a continues to contact the tappet 164 for a long time, and the period during which the cam surface 617b contacts the tappet 164 is shortened. As a result, the lift amount is reduced as a whole, and the angle range from the opening timing to the closing timing, that is, the operating angle is also reduced.

  Conversely, if the eccentric cam portion 612a is positioned downward in the drawing, the rocker arm 613 is positioned downward as a whole, and the end portion 614a of the swing cam 614 is pushed downward relatively. That is, the initial position of the swing cam 614 is inclined in the direction in which the cam surface 617 b approaches the tappet 164. Therefore, when the swing cam 614 swings with the rotation of the drive shaft 621, the portion that contacts the tappet 164 immediately shifts from the base circle surface 617a to the cam surface 617b. As a result, the lift amount as a whole increases and the operating angle also increases.

  Since the position of the eccentric cam portion 612a can be continuously changed, the valve lift characteristic changes continuously as shown in FIG. FIG. 5 is a characteristic diagram showing changes in lift / operating angle characteristics by the lift / operating angle variable mechanism 61. That is, the lift and the operating angle can be continuously expanded and contracted simultaneously. In particular, in this case, the opening timing and the closing timing of the intake valve 162 change substantially symmetrically as the lift and operating angle change.

  In the control according to the present invention, when the overlap of the intake and exhaust valves is largely controlled, it is not necessary to provide both the phase variable mechanism 62 and the lift / operating angle variable mechanism 62 described above, and the valve that can adjust the overlap. Since any mechanism is sufficient, one of the mechanisms 61 and 62 can be omitted.

  Returning to FIG. 1, a crank angle sensor 27 is provided on the crankshaft of the internal combustion engine 1, and the control unit 50 counts a crank unit angle signal output from the crank angle sensor 27 in synchronization with the engine rotation for a certain period of time. Alternatively, the engine speed Ne can be detected by measuring the cycle of the crank reference angle signal.

  The accelerator pedal operated by the driver is provided with an accelerator opening sensor 26 that detects an accelerator opening corresponding to the amount of depression, and a detection signal is output to the control unit 50.

  Further, a torque sensor 28 for detecting the torque of the drive system corresponding to the load of the internal combustion engine 1 is provided in the drive system, and the detection signal is output to the control unit 50.

  As described above, the detection signals from the various sensors 13, 14, 26, 27, 28, 31, 42, 73 include a CPU, a ROM, a RAM, an A / D converter, an input / output interface, and the like. The control unit 50 is input to a control unit 50 composed of a microcomputer, and the control unit 50 controls the opening of the first throttle valve 14 in accordance with the operating state detected based on the signals from the sensors to inject fuel. The valve 17 is driven to control the fuel injection amount, the ignition timing is set, and the ignition plug 20 is ignited at the ignition timing.

  The exhaust gas recirculation mechanism 40 corresponds to the exhaust gas recirculation means of the present invention, and the control unit 50 corresponds to the control means of the present invention.

  Next, a control procedure according to the present embodiment will be described.

  6 is a flowchart showing a control procedure by the control unit 50 of FIG. 1, FIG. 7 is a region map showing EGR control by the control unit 50, and FIG. 8 is a timing chart showing control by the control unit 50.

  The control unit 50 of this example operates the exhaust gas recirculation mechanism 40 in the regions B1, B2, and C of the engine rotation speed-engine torque map shown in FIG. 7 to recirculate the exhaust gas to the intake passage 11. In the region A in the figure, the exhaust gas recirculation mechanism 40 is stopped, and the variable valve mechanism 60 sets the overlap of the intake and exhaust valves so that the exhaust gas remains by so-called internal EGR. Further, exhaust gas recirculation is not performed in regions other than regions A, B1, B2, and C.

  However, the area map shown in the figure is an example for understanding the present invention, and is not intended to limit the present invention. Further, the torque threshold T1 between the region A and the regions B1, B2, and C can be exemplified by a numerical value such as 120 Nm, and the leftmost rotation speed threshold N1 of the regions A, B1, and C can be exemplified as 1200 rpm, but is not limited thereto. Can be changed.

  The regions B1, B2, C corresponding to the high load region higher than the torque T1 are, for example, 20% for the EGR rate of the regions B1, B2 (the ratio of the recirculated gas to the total in-cylinder gas amount), The rate shall be distinguished as 30%.

  In the following flow, the operation state X in the region C in the figure, that is, the relatively high rotation / high load state X shifts to the low rotation / low load state Y on the left side of the region A as shown by the arrow. The case where it does is demonstrated.

  As described above, in the configuration in which the exhaust gas is recirculated to the intake passage 11 upstream of the first throttle valve 14 as in this example, when the throttle valve 14 shifts from the open state to the closed state in accordance with the driver's deceleration request. The recirculated exhaust gas remains in the intake passage 11. Strictly speaking, the recirculation gas remains in the intake passage 11 from the outlet of the recirculation valve 42 of FIG. 1 to the first throttle valve 14. In this example, the recirculated gas is purged, and the engine control including EGR when the accelerator is stepped on next time can be appropriately performed.

  In step S1 of FIG. 6, it is determined whether or not the current operation state is the regions B1, B2, and C shown in FIG. As described above, since the exhaust gas recirculation mechanism 40 is operated when the operation state is in any of the regions B1, B2, and C, the above-described recirculation gas residual problem may occur. On the other hand, when the operating state is in the region A, the variable valve mechanism 60 shown in FIGS. 2 to 5 is driven to adjust the overlap amount of the intake and exhaust valves, thereby executing the internal EGR control. At this time, since the exhaust gas recirculation mechanism 40 is stopped, the above-described recirculation gas remaining problem does not occur.

  If it is determined in step S1 that the operation state is one of the regions B1, B2, and C, the process proceeds to step S2, and if other than the regions B1, B2, and C, step S1 is repeated. In this state, the recirculation valve 42 is open.

  Although illustration is omitted, when the operation state is in any of the regions B1, B2, and C, the recirculation valve 42 of the exhaust gas recirculation mechanism 40 shown in FIG. 1 is opened (in the regions B1, B2, and C). In other words, the exhaust gas is recirculated to the upstream side of the supercharger 30 in the intake passage 11 while cooling a part of the exhaust gas in the exhaust passage 21. As a result, the exhaust gas temperature can be lowered and fuel consumption can be improved.

  In step S2, the accelerator opening APO is read from the accelerator opening sensor 26, and in step S3, it is determined whether or not the accelerator opening is zero. If the accelerator opening APO is not zero in step S3, the process returns to step S1, but if the accelerator opening APO is zero, the process proceeds to step S4, and the opening TVO of the first throttle valve 14 is set to a non-zero idle opening. Set.

  In step S5, the fuel injection from the fuel injection valve 17 is cut when the accelerator opening APO becomes zero.

Further, in steps S6 and S7, the second throttle valve 72 is fully closed and the reflux valve 71 is fully opened. Note that the recirculation valve 42 of the exhaust gas recirculation mechanism 40 remains open. The above corresponds to the times t1 to t2 in FIG.
As described above, when the accelerator opening becomes zero from the high load EGR region (which is also the supercharging region), the first throttle valve 14 shifts to the closed state according to the normal control, so that the recirculation to the intake passage 11 described above is performed. A gas residue occurs. However, in this example, the second throttle valve 72 and the recirculation valve 72 are both fully opened in steps S6 and S7, so that they remain in the intake passage 11 between the supercharged compressor wheel 34 and the first throttle valve 14. The recirculated gas is purged from the opened recirculation valve 42 to the exhaust passage 21 via the reflux passage 70.
Of course, the upstream side of the compressor wheel 34 that is not supercharged is also at a high pressure, so that it is purged to the exhaust passage 21 via the recirculation valve 42. Further, since the second throttle valve 72 is fully closed, the fuel component contained in the recirculation gas is also prevented from adhering to the air flow meter 13.
In step S8, it is determined whether there is a request for reacceleration. This re-acceleration request is determined based on whether or not the accelerator opening APO has become a non-zero positive value, that is, whether or not the driver has stepped on the accelerator again.
If there is no request for reacceleration in step S8, the process proceeds to step S9, where the pressure in the intake passage 11 detected by the pressure sensor 73 is compared with the pressure in the exhaust passage 21 detected by the exhaust pressure sensor 25. The above-described control is continued until the pressure becomes equal to the pressure in the exhaust passage 21. The above corresponds to the times t2 to t3 in FIG.
When the pressure in the intake passage 11 decreases and becomes equal to the pressure in the exhaust passage 21 in step S9, the process proceeds to step S10, and the recirculation valve 42 is fully closed. In step S11 and step S12, the reflux valve 71 is fully closed and the second throttle valve 72 is fully opened. This completes the purge process while preventing the recirculation gas from flowing backward from the exhaust passage 21 via the recirculation passage 41. In step S13, fuel injection is resumed, and the idle state is maintained in step S14. The above corresponds to the times t3 to t4 in FIG.
On the other hand, if there is a request for reacceleration in step S8, the process proceeds to step S15, and the recirculation valve 42 is fully closed. In step S16 and step S17, the reflux valve 71 is fully closed and the second throttle valve 72 is fully opened.
Then, in step S18, the first throttle valve corresponding to the accelerator opening APO or the like

The opening degree TVO of 14 is calculated and set in the normal control flow. In step S19, the fuel cut from the fuel injection valve 17 is stopped, and the fuel injection amount corresponding to the operation request is calculated and set according to the normal control flow.

  In step S20, the exhaust gas recirculation operation in the low load region A, for example, the internal EGR for adjusting the overlap amount of the intake and exhaust valves by driving the variable valve mechanism 60 described above is executed.

  As described above, according to the control apparatus for an internal combustion engine of the present embodiment, even when the first throttle valve 14 is closed and the exhaust gas recirculation mechanism 40 is stopped, the recirculation is performed for a predetermined purge time. Since the valve 71 is opened and the second throttle valve 72 is closed, the recirculation gas remaining in the intake passage 11 between the first throttle valve 14 and the recirculation valve 42 can be purged to the exhaust passage 21. As a result, the intake control during the next operation control such as reacceleration can be accurately executed.

  The supercharger according to the above-described embodiment employs a so-called exhaust turbine-driven supercharger that rotates a compressor wheel by a turbine wheel. A mechanically driven supercharger can also be used.

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 11 ... Intake passage 12 ... Air filter 13 ... Air flow meter 14 ... First throttle valve 15 ... Collector 16 ... Combustion chamber 17 ... Fuel injection valve 20 ... Spark plug 21 ... Exhaust passage 23 ... Muffler 24 ... Exhaust purification catalyst 25 ... Exhaust pressure sensor 26 ... Accelerator opening sensor 27 ... Crank angle sensor 28 ... Torque sensor 30 ... Supercharger 31 ... Waste gate valve 32 ... Turbine wheel 33 ... Rotor shaft 34 ... Compressor wheel 35 ... Detour 36 ... Intercooler 40. Exhaust gas recirculation mechanism (exhaust gas recirculation means)
41 ... Recirculation passage 42 ... Recirculation valve (recirculation valve)
43 ... Refrigerant 50 ... Control unit (control means)
60. Variable valve mechanism (variable valve means)
70 ... Reflux passage 71 ... Reflux valve 72 ... Second throttle valve 73 ... Pressure sensor

Claims (9)

A first throttle valve that is provided in the intake passage and adjusts the intake amount according to the required load;
A supercharger that is provided in the intake passage and supercharges intake air;
Exhaust gas recirculation means having a recirculation passage for recirculating a part of the exhaust gas in the exhaust passage upstream of the supercharger in the intake passage, and a recirculation valve for opening and closing the recirculation passage;
A recirculation passage communicating the downstream side and the upstream side of the supercharger of the intake passage;
A control device for an internal combustion engine comprising a return valve for opening and closing the return passage;
Control means for outputting a control signal for opening the recirculation valve and the recirculation valve for a predetermined time when the exhaust gas recirculation means is shifted from an operating state to an inoperative operating state. A control device for an internal combustion engine. The control apparatus for an internal combustion engine according to claim 1,
An air flow meter provided in the intake passage, and a second throttle valve provided between the air flow meter in the intake passage and the supercharger,
The internal combustion engine characterized in that the control means outputs a control signal for closing the second throttle valve when the exhaust gas recirculation means shifts from an operating state to an inactive operating state. Control device. The control apparatus for an internal combustion engine according to claim 2,
A pressure sensor for detecting a pressure between the second throttle valve in the intake passage and the supercharger;
The internal combustion engine is characterized in that the control means outputs a control signal for closing the recirculation valve when the pressure in the intake passage detected by the pressure sensor becomes equal to the pressure in the exhaust passage. Engine control device. The control apparatus for an internal combustion engine according to claim 3,
The control means outputs a control signal for opening the second throttle valve when the pressure of the intake passage detected by the pressure sensor becomes equal to the pressure of the exhaust passage. Control device for internal combustion engine. The control apparatus for an internal combustion engine according to claim 4,
The internal combustion engine, wherein the control means outputs a control signal for closing the recirculation valve when the pressure of the intake passage detected by the pressure sensor becomes equal to the pressure of the exhaust passage. Control device. In the control device for an internal combustion engine according to any one of claims 1 to 5,
The exhaust gas recirculation means recirculates exhaust gas downstream of an exhaust purification catalyst provided in the exhaust passage to the intake passage upstream of the supercharger,
The internal combustion engine characterized in that the control means outputs a control signal for adjusting the opening of the second throttle valve in accordance with a target recirculation amount of exhaust gas in an operating state in which the exhaust gas recirculation means operates. Engine control device. The control apparatus for an internal combustion engine according to claim 6,
The control device for an internal combustion engine, wherein the control means operates the exhaust gas recirculation means in a high supercharging region where the rotational speed and output torque of the internal combustion engine are each equal to or greater than a predetermined value. The control apparatus for an internal combustion engine according to claim 7,
The control means deactivates the exhaust gas recirculation means and controls the valve overlap of the intake / exhaust valves to execute internal EGR in a case other than the high supercharging region. Control device for internal combustion engine. In the control device for an internal combustion engine according to any one of claims 1 to 8,
The control means closes the recirculation valve and the recirculation valve and outputs the second recirculation valve when there is a request for reacceleration while outputting a signal for opening the recirculation valve and the recirculation valve. A control device for an internal combustion engine, which outputs a control signal for opening a throttle valve.

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