JP2011208596A - Control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To flexibly adjust an EGR rate, boost pressure, an exhaust gas supply amount to a turbine, and the like depending on the state of an internal combustion engine capable of circulating the full amount of exhaust gas of a specific cylinder to an intake system in a control device of the internal combustion engine.SOLUTION: The control device of the internal combustion engine includes: a turbine upstream passage (exhaust manifold 22) connecting exhaust gas ports of turbine drive cylinder groups (#1-#3) and an inlet of the turbine 18 of a turbocharger 16; an exhaust gas circulation passage 34 connecting an exhaust gas port of a circulation gas generation cylinder (#4) and an intake manifold 12; an exhaust gas circulation valve 36; an upstream communication passage 38 interconnecting the exhaust gas circulation passage 34 and the turbine upstream passage; an upstream communication passage open/close valve 40; a downstream communication passage 42 interconnecting the exhaust gas circulation passage 34 and a downstream-side exhaust gas passage 24 of the turbine 18; a downstream communication passage open/close valve 44; and a control means for controlling open/close of each of the exhaust gas circulation valve 36, the upstream communication passage open/close valve 40 and the downstream communication passage open/close valve 44.

Description

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

  Japanese Patent Publication No. 2003-506619 discloses that the entire amount of exhaust gas discharged from a specific cylinder is recirculated to the intake air of all cylinders, and the exhaust gas of other cylinders other than the specific cylinder flows into the turbine of the turbocharger. A multi-cylinder internal combustion engine configured as described above is disclosed. In such an internal combustion engine, assuming that the amount of exhaust gas in each cylinder is the same, the ratio of the exhaust gas that recirculates (EGR rate) depending on the ratio of the number of cylinders that generate the recirculated exhaust gas and the total number of cylinders. Therefore, the predetermined EGR rate can be accurately realized regardless of the engine operating state.

  Even in the internal combustion engine as described above, there is a situation where the EGR rate should be controlled to a value different from the predetermined EGR rate. In such a case, the technique disclosed in the above publication adjusts the exhaust gas amount of the recirculated exhaust gas generating cylinder by setting the fuel injection amount of the recirculated exhaust gas generating cylinder to a value different from that of the other cylinders. The EGR rate is made variable.

JP-T-2003-506619 Japanese Patent No. 3462445

  However, the range in which the exhaust gas amount can be changed only by adjusting the fuel injection amount is limited. For this reason, in the above conventional technique, the range in which the EGR rate can be adjusted is narrow. Therefore, it may be difficult to control the EGR rate to a value required from the engine operating state. Also, if the fuel injection amount is made different between the recirculated exhaust gas generating cylinder and the other cylinders, the generated torque of the recirculated exhaust gas generating cylinder does not become the same as the generated torque of the other cylinders, so that a large torque fluctuation is likely to occur.

  Furthermore, in the above conventional technique, the amount of exhaust gas flowing into the turbine of the turbocharger is always reduced by one cylinder. For this reason, the rotation increase of the turbocharger at the time of acceleration becomes slow, and the acceleration response is inferior.

  The present invention has been made in view of the above points, and in an internal combustion engine that can recirculate the entire amount of exhaust gas of a specific cylinder to the intake system, the EGR rate, the supercharging pressure, and the exhaust gas supply amount to the turbine It is an object of the present invention to provide a control device for an internal combustion engine that can be flexibly adjusted according to the engine state.

In order to achieve the above object, a first invention is an apparatus for controlling a multi-cylinder internal combustion engine having a turbocharger,
The internal combustion engine includes a recirculation gas generating cylinder capable of recirculating the entire amount of exhaust gas to the intake system, and a turbine drive cylinder group capable of supplying the entire amount of exhaust gas to the turbine of the turbocharger.
A turbine upstream passage connecting an exhaust port of the turbine-driven cylinder group and an inlet of the turbine;
An intake manifold that distributes intake air to the reflux gas generation cylinder and the turbine-driven cylinder group;
An exhaust recirculation passage for connecting the exhaust port of the recirculation gas generation cylinder and the intake manifold or an intake passage on the upstream side thereof to send exhaust gas to the intake side of the recirculation gas generation cylinder and the turbine drive cylinder group; ,
An exhaust recirculation valve that can be switched between a fully open state in which exhaust gas in the exhaust recirculation passage flows into the intake side and a fully closed state in which exhaust gas in the exhaust recirculation passage does not flow into the intake side;
An upstream communication passage communicating between the exhaust gas recirculation passage and the turbine upstream passage;
An upstream communication passage opening / closing valve that can be switched between a fully open state in which exhaust gas flows through the upstream communication passage and a fully closed state in which exhaust gas does not flow through the upstream communication passage;
A downstream communication passage communicating between the exhaust gas recirculation passage and an exhaust passage downstream of the turbine;
A downstream communication passage opening / closing valve that can be switched between a fully open state in which exhaust gas flows through the downstream communication passage and a fully closed state in which exhaust gas does not flow through the downstream communication passage;
Control means for controlling opening and closing of each of the exhaust gas recirculation valve, the upstream communication path on-off valve and the downstream communication path on-off valve;
It is characterized by providing.

The second invention is the first invention, wherein
The control means includes means for executing a first mode in which the exhaust gas recirculation valve is fully opened and the upstream communication passage on-off valve and the downstream communication passage on-off valve are fully closed.
During execution of the first mode, the total amount of exhaust gas from the recirculation gas generation cylinder flows into the intake side, and the total amount of exhaust gas from the turbine-driven cylinder group is supplied to the turbine. .

The third invention is the first or second invention, wherein
The control means includes means for executing a second mode in which the exhaust gas recirculation valve is fully opened and the upstream communication passage on-off valve and the downstream communication passage on-off valve are set to an intermediate opening degree,
During execution of the second mode, a part of the exhaust gas of the turbine-driven cylinder group flows into the exhaust gas recirculation path through the upstream communication path, and a part of the exhaust gas in the exhaust gas recirculation path flows to the downstream side. The exhaust gas flows into the exhaust passage on the downstream side of the turbine through the communication passage.

According to a fourth invention, in any one of the first to third inventions,
The control means includes means for executing a third mode in which the exhaust gas recirculation valve is fully opened, the upstream communication passage opening / closing valve is fully opened or an intermediate opening, and the downstream communication passage opening / closing valve is fully closed. ,
During execution of the third mode, a part of the exhaust gas of the turbine-driven cylinder group flows into the exhaust gas recirculation passage through the upstream communication passage, so that the inflowing exhaust gas and the recirculation gas generation cylinder An amount of exhaust gas that is the sum of all the exhaust gases flows into the intake side.

According to a fifth invention, in any one of the first to fourth inventions,
The control means includes means for executing a fourth mode in which the exhaust gas recirculation valve is fully opened, the upstream communication passage opening / closing valve is fully closed, and the downstream communication passage opening / closing valve is at an intermediate opening degree,
During execution of the fourth mode, a part of the exhaust gas of the recirculation gas generating cylinder that has flowed into the exhaust gas recirculation passage flows into the exhaust gas passage on the downstream side of the turbine through the downstream communication passage, and the remaining portion Is supplied to the turbine through the upstream communication passage and the turbine upstream passage.

In a sixth aspect based on any one of the first to fifth aspects, the control means sets the exhaust gas recirculation valve to a fully closed state, sets the upstream communication passage opening / closing valve to a full open state, and sets the downstream communication passage to the downstream communication passage. Means for executing a fifth mode in which the on-off valve is fully closed;
During execution of the fifth mode, the entire amount of exhaust gas in the recirculation gas generation cylinder flows from the exhaust recirculation passage through the upstream communication passage into the turbine upstream passage, thereby the turbine drive cylinder group and the A total amount of exhaust gas in the recirculation gas generation cylinder is supplied to the turbine.

According to a seventh invention, in any one of the first to sixth inventions,
The control means includes means for executing a sixth mode in which the exhaust gas recirculation valve is fully closed, the upstream communication passage opening / closing valve is fully opened, and the downstream communication passage opening / closing valve is at an intermediate opening degree,
During execution of the sixth mode, a part of the exhaust gas in the exhaust recirculation passage flows into the exhaust passage on the downstream side of the turbine through the downstream communication passage, so that the turbine driven cylinder group and the recirculation gas An amount of exhaust gas obtained by subtracting the amount of exhaust gas that has passed through the downstream communication path from the total amount of exhaust gas in the generating cylinder is supplied to the turbine.

Further, an eighth invention is any one of the first to seventh inventions,
The control means includes means for executing a seventh mode in which the exhaust gas recirculation valve is fully closed, and the upstream communication passage on-off valve and the downstream communication passage on-off valve are fully open,
During execution of the seventh mode, most of the exhaust gas of the turbine-driven cylinder group does not pass through the turbine, and passes through the upstream communication path, the exhaust gas recirculation path, and the downstream communication path. It flows into the exhaust passage on the downstream side.

  According to the first invention, in an internal combustion engine that can recirculate the entire amount of exhaust gas in a specific cylinder (recirculation gas generation cylinder) to the intake system, the EGR rate, the supercharging pressure, the exhaust gas supply amount to the turbine, etc. It can be flexibly adjusted according to the engine condition. For this reason, not only when the EGR rate is set to a predetermined ratio, it is possible to perform optimal control for all engine states. In addition, the above effects can be achieved with a simple structure.

  According to the second aspect of the invention, the entire amount of exhaust gas in the recirculation gas generating cylinder can be caused to flow into the intake side, so that the ratio of the recirculated exhaust gas can be kept constant. That is, the EGR rate can be accurately and reliably maintained at a predetermined ratio regardless of the engine speed and the engine load.

  According to the third aspect, it is possible to reduce the supercharging pressure and the back pressure as necessary while executing EGR.

  According to the fourth invention, it is possible to operate at an EGR rate exceeding the predetermined ratio.

  According to the fifth aspect of the invention, it is possible to operate at an EGR rate less than the predetermined ratio.

  According to the sixth aspect of the invention, the amount of exhaust gas flowing into the turbine can be increased, so that the response during acceleration and the output can be improved.

  According to the seventh aspect, it is possible to reduce the supercharging pressure and the back pressure as necessary while allowing a large amount of exhaust gas to flow into the turbine.

  According to the eighth aspect, the temperature of the exhaust gas flowing into the exhaust purification catalyst on the downstream side of the turbine can be maximized. For this reason, the exhaust purification catalyst can be warmed up early.

It is a figure for demonstrating the system configuration | structure of Embodiment 1 of this invention. It is a figure for demonstrating a 1st mode. It is a figure for demonstrating a 2nd mode. It is a figure for demonstrating the 3rd mode. It is a figure for demonstrating 4th mode. It is a figure for demonstrating 5th mode. It is a figure for demonstrating 6th mode. It is a figure for demonstrating 7th mode.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element which is common in each figure, and the overlapping description is abbreviate | omitted.

Embodiment 1 FIG.
FIG. 1 is a diagram for explaining a system configuration according to the first embodiment of the present invention. As shown in FIG. 1, the system of the present embodiment includes an internal combustion engine 10 (hereinafter simply referred to as “engine 10”) mounted on a vehicle or the like. The engine 10 of this embodiment is an in-line four-cylinder type having four cylinders # 1 to # 4. Each cylinder of the engine 10 is provided with a fuel injector, a spark plug, an intake valve, an exhaust valve, and the like. The intake port of each cylinder is connected to the intake manifold 12. An intake passage 14 is connected to the intake manifold 12.

  The engine 10 includes a turbocharger 16. The turbocharger 16 includes a turbine 18 that is rotated by the energy of exhaust gas, and a compressor 20 that is driven by the turbine 18. The exhaust ports of # 1, # 2, and # 3 cylinders are connected to the exhaust manifold 22. The exhaust manifold 22 is connected to the inlet of the turbine 18. An exhaust purification catalyst 26 for purifying exhaust gas is installed in the exhaust passage 24 on the downstream side of the turbine 18. The compressor 20 is disposed in the intake passage 14. An air cleaner 28 is installed at the inlet of the intake passage 14. An intake air passage 14 between the compressor 20 and the intake manifold 12 is provided with an intercooler 30 for cooling intake air compressed by the compressor 20 and a throttle valve 32 for controlling the intake air amount. . The intake air that has passed through the throttle valve 32 is distributed by the intake manifold 12 and flows into the cylinders # 1 to # 4.

  The exhaust port of the # 4 cylinder is connected to one end of the exhaust gas recirculation passage 34. The other end of the exhaust gas recirculation passage 34 is connected to the intake manifold 12. An exhaust gas recirculation valve 36 is installed at a connection portion between the exhaust gas recirculation passage 34 and the intake manifold 12. Between the exhaust gas recirculation passage 34 and the exhaust manifold 22, an upstream communication passage 38 that communicates both is provided. An upstream communication passage opening / closing valve 40 is installed in the middle or end of the upstream communication passage 38. Further, a downstream communication passage 42 is provided between the exhaust gas recirculation passage 34 and the exhaust passage 24 on the downstream side of the turbine 18. A downstream communication passage opening / closing valve 44 is installed in the middle or at the end of the downstream communication passage 42. The other end of the exhaust gas recirculation passage 34 may be connected to the intake passage 14 between the exhaust manifold 22 and the throttle valve 32.

  The system of the present embodiment further includes a sensor system including each sensor described below, and an ECU (Electronic Control Unit) 50 that controls the operation of each actuator provided for the engine 10. The air / fuel ratio sensor 46 detects the air / fuel ratio of the exhaust gas flowing into the exhaust purification catalyst 26. The crank angle sensor 52 outputs a signal synchronized with the rotation of the crankshaft of the engine 10. The ECU 50 can detect the engine speed and the crank angle based on the output of the crank angle sensor 52. The air flow meter 54 detects the amount of fresh air drawn into the intake passage 14. The intake air temperature sensor 56 detects the temperature of intake air. The supercharging pressure sensor 58 detects the pressure (supercharging pressure) on the outlet side of the compressor 20. The accelerator opening sensor 60 detects the amount of operation of the accelerator pedal (accelerator opening) by the driver of the vehicle. The vehicle speed sensor 62 detects the speed of the vehicle.

  In addition to the above, the sensor system includes various sensors necessary for controlling the vehicle and the engine (for example, a water temperature sensor that detects the temperature of engine cooling water). Connected to the input side. In addition to the throttle valve 32, the exhaust gas recirculation valve 36, the upstream communication passage opening / closing valve 40, and the downstream communication passage opening / closing valve 44, various actuators including a fuel injector, a spark plug, and the like are connected to the output side of the ECU 50. ing.

  The ECU 50 detects the operation information of the engine by the sensor system, and controls the operation by driving each actuator based on the detection result. Specifically, the engine speed and the crank angle are detected based on the output of the crank angle sensor 52, and the intake air amount is detected by the air flow meter 54. Further, the fuel injection amount is calculated based on the intake air amount, the engine speed, etc., and after determining the fuel injection timing, ignition timing, etc. based on the crank angle, the fuel injector and spark plug are driven.

  Further, the ECU 50 calculates a target EGR rate based on the engine operation information detected by the sensor system and a predetermined EGR rate map, and the exhaust recirculation valve 36, the upper valve so as to realize the target EGR rate. The opening and closing of each of the flow communication passage opening / closing valve 40 and the downstream communication passage opening / closing valve 44 are controlled. At this time, the ECU 50 can selectively execute first to seventh modes, which will be described later, as control modes for the exhaust gas recirculation valve 36, the upstream communication passage opening / closing valve 40 and the downstream communication passage opening / closing valve 44. Hereinafter, each control mode will be sequentially described with reference to FIGS. 2 to 8, the open / close states of the exhaust gas recirculation valve 36, the upstream communication passage opening / closing valve 40, and the downstream communication passage opening / closing valve 44 are represented as follows. A white background represents a fully open state. Black fill represents a fully closed state. The shaded area represents an opening between the fully open state and the fully closed state (hereinafter referred to as “intermediate opening”). In the fully open state, the exhaust gas is allowed to flow. In the fully closed state, the flow of exhaust gas is blocked. At the intermediate opening, the passage amount of the exhaust gas is limited according to the opening.

(First mode)
FIG. 2 is a diagram for explaining the first mode. As shown in FIG. 2, in the first mode, the exhaust gas recirculation valve 36 is fully opened, and the upstream communication passage opening / closing valve 40 and the downstream communication passage opening / closing valve 44 are fully closed. During the execution of the first mode, the entire amount of exhaust gas of the # 4 cylinder is sent to the intake manifold 12 through the exhaust recirculation passage 34 and is recirculated to the intake side of the # 1 to # 4 cylinders. On the other hand, the entire exhaust gas of cylinders # 1 to # 3 is supplied to the turbine 18. In such a first mode, the total amount of exhaust gas of one cylinder (# 4 cylinder) among all four cylinders becomes the exhaust gas recirculation gas. For this reason, when the exhaust gas amount of each cylinder is equal, the EGR rate is accurately 25% (1/4). Therefore, according to the first mode, the EGR rate can be accurately and reliably maintained at a predetermined ratio (25% in this embodiment) regardless of the engine speed and the engine load.

(Second mode)
FIG. 3 is a diagram for explaining the second mode. As shown in FIG. 3, in the second mode, the exhaust gas recirculation valve 36 is fully opened, and the upstream communication passage opening / closing valve 40 and the downstream communication passage opening / closing valve 44 are set to intermediate openings. During execution of the second mode, a part of the exhaust gases of the # 1 to # 3 cylinders in the exhaust manifold 22 flows into the exhaust gas recirculation passage 34 through the upstream communication passage 38. A part of the exhaust gas in the exhaust gas recirculation passage 34 flows into the exhaust passage 24 on the downstream side of the turbine 18 through the downstream communication passage 42. In this case, a part of the exhaust gas of the # 1 to # 3 cylinders in the exhaust manifold 22 does not pass through the turbine 18, and passes through the upstream communication path 38, the exhaust gas recirculation path 34, and the downstream communication path 42. Into the exhaust passage 24 on the downstream side. Accordingly, when it is necessary to reduce the supercharging pressure (for example, when knocking is to be prevented), or when it is necessary to reduce the back pressure of the # 1 to # 3 cylinders (hereinafter simply referred to as “back pressure”). In the case of improving the fuel consumption (for example, when the fuel economy is improved), the supercharging pressure and the back pressure can be reduced by setting the second mode.

  In the second mode, by controlling the opening degree of the upstream communication passage opening / closing valve 40 and the downstream communication passage opening / closing valve 44, the exhaust gas amount passing through the upstream communication passage 38 and the exhaust gas amount passing through the downstream communication passage 42 are controlled. The ratio can be controlled. When the exhaust gas amount passing through the upstream communication passage 38 and the exhaust gas amount passing through the downstream communication passage 42 are controlled to be equal, the EGR rate can be maintained at 25%. On the other hand, when it is necessary to control the EGR rate to be less than 25%, the exhaust gas amount passing through the downstream communication passage 42 is controlled to be less than 25% by controlling the exhaust gas amount passing through the upstream communication passage 38 to be smaller. An EGR rate of less than can be realized. Further, when it is necessary to control the EGR rate to exceed 25%, the exhaust gas amount passing through the downstream communication passage 42 is controlled so that the exhaust gas amount passing through the upstream communication passage 38 becomes smaller, so that 25% An EGR rate exceeding 1 can be realized.

(Third mode)
FIG. 4 is a diagram for explaining the third mode. As shown in FIG. 4, in the third mode, the exhaust gas recirculation valve 36 is fully opened, the upstream communication passage opening / closing valve 40 is fully opened or an intermediate opening degree, and the downstream communication passage opening / closing valve 44 is fully closed. During execution of the third mode, a part of the exhaust gases of the # 1 to # 3 cylinders in the exhaust manifold 22 flows into the exhaust gas recirculation passage 34 through the upstream communication passage 38. Therefore, the exhaust gas recirculation amount is the sum of the total amount of exhaust gas of the # 4 cylinder and the exhaust gas amount that flows from the exhaust manifold 22 through the upstream communication passage 38 into the exhaust gas recirculation passage 34. For this reason, the EGR rate exceeds 25%. When the target EGR rate exceeds 25%, the target EGR rate can be realized by setting the third mode and controlling the opening degree of the upstream communication passage opening / closing valve 40.

(4th mode)
FIG. 5 is a diagram for explaining the fourth mode. As shown in FIG. 5, in the fourth mode, the exhaust gas recirculation valve 36 is fully opened, the upstream communication passage opening / closing valve 40 is fully closed, and the downstream communication passage opening / closing valve 44 is set to an intermediate opening. During execution of the fourth mode, part of the exhaust gas in the exhaust gas recirculation passage 34 flows into the exhaust passage 24 on the downstream side of the turbine 18 through the downstream communication passage 42. Therefore, the exhaust gas recirculation amount is an amount obtained by subtracting the exhaust gas amount that has passed through the downstream communication passage 42 from the total amount of exhaust gas of the # 4 cylinder. Therefore, in this case, the EGR rate is less than 25%. When the target EGR rate is less than 25%, the target EGR rate can be realized by setting the fourth mode and controlling the opening degree of the downstream communication passage opening / closing valve 44.

(5th mode)
FIG. 6 is a diagram for explaining the fifth mode. As shown in FIG. 6, in the fifth mode, the exhaust gas recirculation valve 36 is fully closed, the upstream communication passage opening / closing valve 40 is fully opened, and the downstream communication passage opening / closing valve 44 is fully closed. During the execution of the fifth mode, the entire amount of exhaust gas of the # 4 cylinder flows into the exhaust manifold 22 from the exhaust gas recirculation passage 34 through the upstream communication passage 38. Therefore, the EGR rate is 0%, and the entire amount of exhaust gas of all cylinders # 1 to # 4 is supplied to the turbine 18. For this reason, the rotation speed of the turbocharger 16 can be raised rapidly. When a high output is required, such as during acceleration, the fifth mode is controlled. Thereby, the response at the time of acceleration can be improved and the output can be improved.

(Sixth mode)
FIG. 7 is a diagram for explaining the sixth mode. As shown in FIG. 7, in the sixth mode, the exhaust gas recirculation valve 36 is fully closed, the upstream communication passage opening / closing valve 40 is fully opened, and the downstream communication passage opening / closing valve 44 is set to an intermediate opening. During execution of the sixth mode, a part of the exhaust gas in the exhaust gas recirculation passage 34, that is, the exhaust gas of the # 4 cylinder flows into the exhaust passage 24 on the downstream side of the turbine 18 through the downstream communication passage 42. . The remaining part of the exhaust gas of the # 4 cylinder, excluding the above part, flows into the exhaust manifold 22 through the upstream communication passage 38, and merges with the exhaust gas of the cylinders # 1 to # 3, and the turbine. 18 is supplied. In this case, the amount of exhaust gas supplied to the turbine 18 is an amount obtained by subtracting the amount of exhaust gas that has passed through the downstream communication passage opening / closing valve 44 from the total amount of exhaust gas of all cylinders # 1 to # 4. In the sixth mode, the downstream communication passage opening / closing valve 44 functions in the same manner as a wastegate valve of a general turbocharger. That is, by controlling the opening degree of the downstream communication passage opening / closing valve 44, the amount of exhaust gas flowing through the exhaust passage 24 on the downstream side of the turbine 18 without passing through the turbine 18 can be controlled. When it is necessary to reduce the supercharging pressure, it is possible to control the supercharging pressure to the target value by setting the sixth mode and controlling the opening degree of the downstream communication passage opening / closing valve 44.

(Seventh mode)
FIG. 8 is a diagram for explaining the seventh mode. As shown in FIG. 8, in the seventh mode, the exhaust gas recirculation valve 36 is fully closed, and the upstream communication passage opening / closing valve 40 and the downstream communication passage opening / closing valve 44 are fully opened. During the execution of the seventh mode, the entire amount of exhaust gas of the # 4 cylinder flows into the exhaust passage 24 on the downstream side of the turbine 18 through the downstream communication passage 42. Further, the resistance passing from the exhaust manifold 22 through the upstream communication path 38, the exhaust gas recirculation path 34 and the downstream communication path 42 to bypass the turbine 18 is smaller than the resistance passing through the turbine 18. For this reason, most of the exhaust gases of the # 1 to # 3 cylinders do not pass through the turbine 18, pass through the upstream communication passage 38, the exhaust gas recirculation passage 34, and the downstream communication passage 42, so 24. Therefore, in the seventh mode, most of the exhaust gases of all cylinders # 1 to # 4 can be directly flowed into the exhaust purification catalyst 26 without passing through the turbine 18. When the exhaust purification catalyst 26 needs to be warmed up, such as during a cold start, the amount of work that the exhaust gas performs on the turbine 18 is minimized by setting the seventh mode. The temperature of the exhaust gas flowing into 26 can be maximized. For this reason, the exhaust purification catalyst 26 can be warmed up early.

  As described above, according to the present embodiment, the EGR rate, the supercharging pressure, the back pressure, and the turbine 18 are supplied by selectively executing the first to seventh modes according to the state of the engine 10. The amount of exhaust gas, the catalyst warm-up state, etc. can be adjusted flexibly. For this reason, not only when the EGR rate is set to a predetermined ratio (first mode), it is possible to optimally control all engine states.

  In the first embodiment described above, the # 4 cylinder is the “recirculation gas generation cylinder” in the first invention, and the # 1 to # 3 cylinders are the “turbine drive cylinder group” in the first invention. 22 respectively correspond to the “turbine upstream passage” in the first invention.

  The present invention is not limited to an in-line 4-cylinder engine, and can be applied to various multi-cylinder engines such as an in-line 3-cylinder, in-line 6-cylinder, V-type 6-cylinder, and V-type 8-cylinder. The number of recirculation gas generation cylinders is not limited to one, and may be two or more.

10 internal combustion engine 12 intake manifold 14 intake passage 16 turbocharger 18 turbine 20 compressor 22 exhaust manifold 24 exhaust passage 26 exhaust purification catalyst 34 exhaust recirculation passage 36 exhaust recirculation valve 38 upstream communication passage 40 upstream communication passage on-off valve 42 downstream communication passage 44 downstream Communication passage opening / closing valve

Claims (8)

An apparatus for controlling a multi-cylinder internal combustion engine having a turbocharger,
The internal combustion engine includes a recirculation gas generating cylinder capable of recirculating the entire amount of exhaust gas to the intake system, and a turbine drive cylinder group capable of supplying the entire amount of exhaust gas to the turbine of the turbocharger.
A turbine upstream passage connecting an exhaust port of the turbine-driven cylinder group and an inlet of the turbine;
An intake manifold that distributes intake air to the reflux gas generation cylinder and the turbine-driven cylinder group;
An exhaust recirculation passage for connecting the exhaust port of the recirculation gas generation cylinder and the intake manifold or an intake passage on the upstream side thereof to send exhaust gas to the intake side of the recirculation gas generation cylinder and the turbine drive cylinder group; ,
An exhaust recirculation valve that can be switched between a fully open state in which exhaust gas in the exhaust recirculation passage flows into the intake side and a fully closed state in which exhaust gas in the exhaust recirculation passage does not flow into the intake side;
An upstream communication passage communicating between the exhaust gas recirculation passage and the turbine upstream passage;
An upstream communication passage opening / closing valve that can be switched between a fully open state in which exhaust gas flows through the upstream communication passage and a fully closed state in which exhaust gas does not flow through the upstream communication passage;
A downstream communication passage communicating between the exhaust gas recirculation passage and an exhaust passage downstream of the turbine;
A downstream communication passage opening / closing valve that can be switched between a fully open state in which exhaust gas flows through the downstream communication passage and a fully closed state in which exhaust gas does not flow through the downstream communication passage;
Control means for controlling opening and closing of each of the exhaust gas recirculation valve, the upstream communication path on-off valve and the downstream communication path on-off valve;
A control device for an internal combustion engine, comprising: The control means includes means for executing a first mode in which the exhaust gas recirculation valve is fully opened and the upstream communication passage on-off valve and the downstream communication passage on-off valve are fully closed.
During execution of the first mode, the total amount of exhaust gas from the recirculation gas generation cylinder flows into the intake side, and the total amount of exhaust gas from the turbine-driven cylinder group is supplied to the turbine. The control device for an internal combustion engine according to claim 1. The control means includes means for executing a second mode in which the exhaust gas recirculation valve is fully opened and the upstream communication passage on-off valve and the downstream communication passage on-off valve are set to an intermediate opening degree,
During execution of the second mode, a part of the exhaust gas of the turbine-driven cylinder group flows into the exhaust gas recirculation path through the upstream communication path, and a part of the exhaust gas in the exhaust gas recirculation path flows to the downstream side. 3. The control device for an internal combustion engine according to claim 1, wherein the control device flows into the exhaust passage on the downstream side of the turbine through the communication passage. The control means includes means for executing a third mode in which the exhaust gas recirculation valve is fully opened, the upstream communication passage opening / closing valve is fully opened or an intermediate opening, and the downstream communication passage opening / closing valve is fully closed. ,
During execution of the third mode, a part of the exhaust gas of the turbine-driven cylinder group flows into the exhaust gas recirculation passage through the upstream communication passage, so that the inflowing exhaust gas and the recirculation gas generation cylinder 4. The control device for an internal combustion engine according to claim 1, wherein an amount of exhaust gas that is the sum of all the exhaust gases flows into the intake side. 5. The control means includes means for executing a fourth mode in which the exhaust gas recirculation valve is fully opened, the upstream communication passage opening / closing valve is fully closed, and the downstream communication passage opening / closing valve is at an intermediate opening degree,
During execution of the fourth mode, a part of the exhaust gas of the recirculation gas generating cylinder that has flowed into the exhaust gas recirculation passage flows into the exhaust gas passage on the downstream side of the turbine through the downstream communication passage, and the remaining portion 5. The control device for an internal combustion engine according to claim 1, wherein the engine is supplied to the turbine through the upstream communication passage and the turbine upstream passage. 6. The control means includes means for executing a fifth mode in which the exhaust gas recirculation valve is fully closed, the upstream communication passage opening / closing valve is fully opened, and the downstream communication passage opening / closing valve is fully closed,
During execution of the fifth mode, the entire amount of exhaust gas in the recirculation gas generation cylinder flows from the exhaust recirculation passage through the upstream communication passage into the turbine upstream passage, thereby the turbine drive cylinder group and the The control apparatus for an internal combustion engine according to any one of claims 1 to 5, wherein the entire amount of exhaust gas in the recirculation gas generation cylinder is supplied to the turbine. The control means includes means for executing a sixth mode in which the exhaust gas recirculation valve is fully closed, the upstream communication passage opening / closing valve is fully opened, and the downstream communication passage opening / closing valve is at an intermediate opening degree,
During execution of the sixth mode, a part of the exhaust gas in the exhaust recirculation passage flows into the exhaust passage on the downstream side of the turbine through the downstream communication passage, so that the turbine driven cylinder group and the recirculation gas The exhaust gas in an amount obtained by subtracting the amount of exhaust gas that has passed through the downstream communication path from the total amount of exhaust gas in the generating cylinder is supplied to the turbine. Control device for internal combustion engine. The control means includes means for executing a seventh mode in which the exhaust gas recirculation valve is fully closed, and the upstream communication passage on-off valve and the downstream communication passage on-off valve are fully open,
During execution of the seventh mode, most of the exhaust gas of the turbine-driven cylinder group does not pass through the turbine, and passes through the upstream communication path, the exhaust gas recirculation path, and the downstream communication path. 8. The control device for an internal combustion engine according to claim 1, wherein the control device flows into an exhaust passage on the downstream side.

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