JP2010163937A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for an internal combustion engine, capable of extending, in an internal combustion engine provided with an exhaust gas recirculation device, the period for recirculating exhaust gas through an exhaust gas recirculation passage while suppressing freezing of condensed water in an intake passage and deterioration of burning state in a combustion chamber. <P>SOLUTION: Cooling time control is executed in cooling of an engine. In the cooling time control, a tumble control valve (TCV) 30 is controlled, when recirculating EGR gas through an EGR passage 21, so that the passage sectional area (Scold) of an intake passage 13 is smaller than the passage sectional area (Swarm) of the intake passage 13 in engine warming time (Scold<Swarm). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an internal combustion engine control device that includes an exhaust gas recirculation device that recirculates part of exhaust gas to an intake passage and an airflow control valve that generates a vortex flow in a combustion chamber.

  2. Description of the Related Art Conventionally, an internal combustion engine includes an exhaust gas recirculation device (EGR device) that recirculates a part of exhaust gas to an intake passage through an exhaust gas recirculation passage (EGR passage) that connects the exhaust passage and the intake passage. Are known. In such an EGR device, an EGR valve for adjusting the amount of exhaust gas flowing through the EGR passage is provided in the EGR passage, and the opening degree of the EGR valve is controlled according to the engine operating state, so that the intake passage The amount of exhaust gas recirculated is adjusted to an amount suitable for the engine operating condition. In this way, an amount of exhaust gas suitable for the engine operating state is recirculated to the combustion chamber, so that the combustion temperature in the combustion chamber is lowered, so that cooling loss can be reduced and fuel efficiency can be improved. Further, in an internal combustion engine in which an intake air amount adjustment valve (throttle valve) for adjusting the intake air amount is provided in the intake passage, the pumping loss can be reduced by recirculating the exhaust gas through the EGR passage. It is also possible to improve fuel efficiency.

  Conventionally, an internal combustion engine in which an airflow control valve for generating a vortex flow such as a tumble flow (vertical vortex) or a swirl flow (lateral vortex) in a combustion chamber is provided in an intake passage is known. By generating such a vortex, the intake air and the fuel are mixed well in the combustion chamber and the combustion speed of the air-fuel mixture is increased, so that the combustion state is stabilized. For example, in the internal combustion engine described in Patent Document 1, in addition to the exhaust gas recirculation device described above, an airflow control valve that generates a swirl flow is provided in the intake passage.

JP 2006-266159 A

  By the way, the exhaust gas recirculated to the intake passage through the EGR passage described above contains moisture generated by the combustion of the air-fuel mixture. Therefore, if the exhaust gas is recirculated when the internal combustion engine is cold, condensed water is generated by cooling the exhaust gas in the intake passage, and there is a concern that the generated condensed water may freeze. Furthermore, if the generation of such condensed water proceeds, the intake passage may be blocked. Further, since the combustion state in the combustion chamber is unstable when the internal combustion engine is cold, there is a concern that if the exhaust gas is recirculated in such a state, the combustion state is further deteriorated.

  Therefore, conventionally, when the internal combustion engine is cold, the exhaust gas is not recirculated through the EGR passage, and the exhaust gas recirculation is started when the internal combustion engine is warmed up. Therefore, there is a problem to be improved in that the exhaust gas cannot be recirculated through the EGR passage as described above when the internal combustion engine is cold.

  The present invention has been made in view of such circumstances, and an object thereof is to suppress freezing of condensed water in an intake passage and deterioration of a combustion state in a combustion chamber in an internal combustion engine including an exhaust gas recirculation device. An object of the present invention is to provide a control device for an internal combustion engine capable of extending the period of recirculation of exhaust gas through an exhaust gas recirculation passage.

In the following, means for achieving the above object and its effects are described.
According to a first aspect of the present invention, an exhaust gas recirculation device that recirculates a part of exhaust gas to the intake passage through an exhaust gas recirculation passage that communicates an intake passage and an exhaust passage of an internal combustion engine, and the intake passage is provided. And an airflow control valve that generates a vortex flow in the combustion chamber of the engine by adjusting a passage cross-sectional area of the intake passage, and when the engine is cold, the exhaust gas is exhausted through the exhaust gas recirculation passage. When the engine is recirculated, a cold time control is performed to control the air flow control valve so that a passage sectional area of the intake passage is smaller than a passage sectional area of the intake passage when the engine is warm. And

  In the above configuration, when the engine is cold, the air flow control valve is set so that the passage cross-sectional area of the intake passage is smaller than the cross-sectional area of the intake passage when the engine is warm when the exhaust gas is recirculated through the exhaust recirculation passage. To control. As a result, when the engine is cold, the flow speed of the intake air flowing through the intake passage is faster than when the engine is warm, so that the condensed water generated in the intake passage can be blown off with a strong air flow, Freezing of condensed water can be suppressed.

  Further, by controlling the airflow control valve as described above, a stronger vortex flow is generated in the combustion chamber than when the engine is warm. Therefore, even when the exhaust gas is recirculated when the engine is cold, which tends to be more unstable than when the engine is warm, the mixture of intake air and fuel is mixed well and the combustion speed is increased. The combustion state can be stabilized.

  Therefore, according to this configuration, the period during which the exhaust gas can be recirculated through the exhaust gas recirculation passage while suppressing the freezing of the condensed water in the intake passage and the deterioration of the combustion state in the combustion chamber is extended to the time when the engine is cold. Will be able to. Thereby, for the purpose of improving fuel consumption, it is possible to suitably set a period during which the exhaust gas is recirculated.

  According to a second aspect of the present invention, in the control device for an internal combustion engine according to the first aspect, the wall surface temperature estimation means for estimating a wall surface temperature around the opening of the exhaust gas recirculation passage in the intake passage is provided, The gist is to stop the cold control when the wall surface temperature estimated based on the temperature estimation means is equal to or higher than a predetermined temperature higher than zero degrees.

  Here, when intake air having a low temperature of zero degrees or less flows through the intake passage, the wall surface temperature of the intake passage may drop to zero degrees or less due to cooling of the wall surface of the intake passage. Then, when the exhaust gas recirculation is performed through the exhaust gas recirculation passage as described above when the wall surface temperature of the intake passage is equal to or lower than 0 ° C., the condensed water contained in the exhaust gas is frozen in the intake passage. There is concern. In particular, such condensed water tends to be generated around the opening of the exhaust gas recirculation passage, which is a portion where exhaust gas is first introduced into the intake passage.

  On the other hand, even when the intake air temperature is less than or equal to zero degrees, the wall temperature of the intake passage may become higher than zero degrees as the internal combustion engine warms up. Freezing of condensed water will be suppressed.

  Therefore, in the above configuration, the cold control is stopped when the wall surface temperature around the opening estimated based on the wall surface temperature estimating means is equal to or higher than a predetermined temperature higher than zero degrees. As described above, by determining whether or not the condensate water is likely to be frozen based on the wall surface temperature, the execution period of the cold control for the purpose of suppressing the condensate water freezing is longer than necessary. Can be suppressed.

  According to a third aspect of the present invention, in the control apparatus for an internal combustion engine according to the second aspect, the apparatus further comprises a water temperature detecting means for detecting a cooling water temperature of the engine, and is estimated based on the wall surface temperature estimating means. The cold time control is performed when the temperature is equal to or higher than a predetermined temperature higher than zero and the cooling water temperature detected by the water temperature detecting means is equal to or higher than a second predetermined temperature at which the combustion state in the combustion chamber is determined to be stable. The gist is to stop.

As the coolant temperature rises as the internal combustion engine warms up, the combustion state becomes stable in the combustion chamber.
Therefore, in the above configuration, the estimated wall surface temperature around the opening is equal to or higher than a predetermined temperature higher than zero, and the detected coolant temperature is equal to or higher than a second predetermined temperature at which the combustion state in the combustion chamber is determined to be stable. In such a case, the cold control is stopped. Therefore, it is possible to suppress the execution period of the cold time control for suppressing the freezing of the condensed water in the intake passage and the deterioration of the combustion state in the combustion chamber from being unnecessarily long.

  According to a fourth aspect of the present invention, in the control device for an internal combustion engine according to any one of the first to third aspects, the intake air flowing through the intake passage is upstream of the airflow control valve in the intake passage. An engine operation in which an intake air amount adjusting valve for adjusting the amount is arranged, and when the engine is cold, the pumping loss is reduced with the execution of the cold time control compared to the non-execution of the cold time control. The gist of the present invention is to provide a judging means for judging that the engine is in a state, and to execute the cold control when the judging means judges that the engine operating state reduces the pumping loss.

  When the intake air amount adjusting valve described above is provided in the intake passage, the intake air amount adjusting valve is opened as the exhaust gas recirculates through the exhaust gas recirculation passage as compared to when the recirculation is not executed. Since the degree increases, the pumping loss is reduced.

  On the other hand, when the above-described cold control is executed, the airflow control valve is adjusted so that the passage cross-sectional area of the intake passage is reduced. Therefore, the pumping loss is reduced by the amount that the passage cross-sectional area of the intake passage is reduced. Will increase.

  Therefore, in order to improve fuel efficiency, the reduction in pumping loss due to the opening of the intake air amount adjustment valve is compared with the increase in pumping loss due to the passage cross-sectional area being reduced by the airflow control valve. Therefore, it is desirable to execute the cold control in the engine operation state in which the pumping loss can be further reduced.

  In view of this, in the above configuration, when the engine is cold, there is provided a determination unit that determines that the engine operating state is such that the pumping loss is reduced as compared with the non-execution of the cold time control when the cold time control is executed. When the determination means determines that the engine operating state reduces the pumping loss, the cold control is executed. As described above, by executing the cold time control in a suitable period for executing the cold time control, it is possible to effectively improve the fuel consumption.

  When it is determined by the determination means that the engine operating state does not reduce the pumping loss, the cross-sectional area of the intake passage by the airflow control valve is set to a fully open state, as in the fifth aspect of the invention. The exhaust gas recirculation through the exhaust gas recirculation passage can be stopped.

As the airflow control valve, as in the sixth aspect of the invention, it is possible to adopt a configuration such as a tumble control valve that generates a tumble flow in the combustion chamber.
According to a seventh aspect of the present invention, in the control device for an internal combustion engine according to the sixth aspect, in the intake passage, an internal space of the intake passage is divided into a plurality of divided intake passages along the axis of the intake passage. The gist is that a partition wall is disposed.

  As described above, when the partition wall is disposed in the intake passage, the intake air is drifted by adjusting the passage cross-sectional area of the intake passage by the tumble control valve which is an airflow control valve, and thus the drifted intake air Can be sent to the combustion chamber side along the partition wall.

  Therefore, a favorable tumble flow can be generated in the combustion chamber by the air flow control valve and the partition wall, and the combustion state can be stabilized more effectively in the combustion chamber.

  As the passage cross-sectional area of the intake passage adjusted by the airflow control valve described above, the cross-sectional area of the intake passage adjusted by the airflow control valve when the engine is warm may be plural. Among the divided intake passages, the sectional area of the divided intake passage formed on the opening side of the exhaust gas recirculation passage in the intake passage is set to be substantially the same. A mode in which the cross-sectional area is adjusted by the airflow control valve so that the cross-sectional area becomes smaller than the cross-sectional area of the divided intake passage can be employed.

  According to a ninth aspect of the present invention, in the control device for an internal combustion engine according to the seventh or eighth aspect, the partition is disposed so as to face an opening of the exhaust gas recirculation passage in the intake passage. Is the gist.

  According to the above configuration, since the partition wall is disposed so as to face the opening of the exhaust gas recirculation passage in the intake passage, the intake air that is drifted by the airflow control valve to increase the flow velocity is formed along the partition wall. Pass through the surroundings. Therefore, it is possible to suppress the generation of condensed water around the opening, which tends to generate condensed water, or to remove the generated condensed water. Therefore, it becomes possible to more effectively suppress the freezing of condensed water.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an internal combustion engine to which the control device for an internal combustion engine according to the present invention is embodied and a peripheral configuration thereof; FIG. 2 is an enlarged view of a structure within a dashed line A in FIG. The figure which shows the relationship between an engine speed and an engine load, and the execution area | region of normal control and cold time control. The figure which shows the relationship between cooling water temperature and wall surface temperature, and the execution area | region of cold control and normal control. The flowchart which shows the procedure of the process performed in the same embodiment. The time chart which shows the state of the EGR valve and tumble control valve which are controlled through execution of cold time control and normal control in the same embodiment. The schematic diagram which shows the internal combustion engine to which the control apparatus concerning 2nd Embodiment is applied, and its periphery structure. The flowchart which shows the procedure of the process performed in the same embodiment. It is a modification of 1st Embodiment, Comprising: The schematic diagram which shows the structure of the part corresponding to the part shown in FIG. FIG. 6 is a schematic diagram showing a configuration of a portion corresponding to the portion shown in FIG. 2, which is another modification of the first embodiment. The schematic diagram which shows the internal combustion engine in the other modification of 1st Embodiment, and its periphery structure.

(First embodiment)
A first embodiment in which a control device for an internal combustion engine according to the present invention is embodied will be described below with reference to FIGS.

  FIG. 1 shows an internal combustion engine 10 to which the control device according to the present embodiment is applied and its peripheral configuration. The internal combustion engine 10 is a vehicular in-cylinder injection gasoline engine. As shown in FIG. 1, a piston 11 is slidably accommodated in a cylinder of the internal combustion engine 10. A combustion chamber 12 is defined by the top surface of the piston 11 and the inner peripheral surface of the cylinder, and an intake passage 13 and an exhaust passage 14 are connected to the combustion chamber 12, respectively.

  The combustion chamber 12 is provided with a fuel injection valve 15 that injects fuel into the combustion chamber 12 and an ignition plug 16 that ignites a mixture of fuel and air in the combustion chamber 12. In addition, a crankshaft 17 that is rotated by reciprocating movement of the piston 11 is connected to the piston 11 via a connecting rod 17a.

  The intake passage 13 is provided with a throttle valve 18 for adjusting the amount of intake air flowing through the intake passage 13 and a throttle motor 19 for adjusting the opening of the throttle valve 18.

  Further, a tumble control valve (hereinafter abbreviated as “TCV”) that generates a tumble flow in the combustion chamber 12 by adjusting the cross-sectional area of the intake passage 13 downstream of the throttle valve 18 in the intake passage 13. ) 30 and an actuator 32 that opens and closes the TCV 30. As shown in FIG. 2, the TCV 30 has a plate-like valve body 30 a that drifts intake air and an end portion 30 b on the intake upstream side of the valve body 30 a that is pivotally supported with respect to the intake passage 13. It is comprised with the rotating shaft 31 which does.

  Further, a partition wall 33 that divides the internal space of the intake passage 13 into a plurality of divided intake passages 13 a and 13 b along the axis C is disposed downstream of the TCV 30 in the intake passage 13. Specifically, the partition wall 33 is disposed at a position where the passage sectional areas Sa and Sb of the divided intake passages 13a and 13b are substantially the same.

  When the TCV 30 is driven by the actuator 32 and the intake air is drifted to the divided intake passage 13a side by the valve body 30a, the passage cross-sectional area of the intake passage 13 is reduced, and the flow velocity of the intake air flowing through the intake passage 13 is increased. Get faster. The intake air thus drifted is sent to the combustion chamber 12 side along the partition wall 33, and a tumble flow is generated in the combustion chamber 12. Note that the flow velocity of the intake air and the strength of the tumble flow are adjusted by adjusting the cross-sectional area of the passage through the control of the opening / closing position of the valve body 30a of the TCV 30.

  The internal combustion engine 10 is provided with an EGR device 20 that recirculates a part of the exhaust gas flowing through the exhaust passage 14 to the intake passage 13 as EGR gas. The EGR device 20 includes an EGR passage 21 that connects the intake passage 13 and the exhaust passage 14, and an EGR valve 22 that is provided in the EGR passage 21 and adjusts the amount of EGR gas (EGR amount) that flows through the passage 21. And an EGR motor 23 that adjusts the opening degree of the EGR valve 22. Note that the opening 21 </ b> A of the EGR passage 21 in the intake passage 13 is formed at a position facing the partition wall 33. Thus, when the EGR valve 22 is opened through the drive of the EGR motor 23, EGR gas is introduced into the divided intake passage 13 a formed by the partition wall 33 on the downstream side of the TCV 30 in the intake passage 13.

  Various controls of the internal combustion engine 10 are performed by the electronic control unit 40. The electronic control unit 40 includes a CPU that executes arithmetic processing related to control of the internal combustion engine 10, a ROM that stores programs and data necessary for the control, a RAM that temporarily stores arithmetic results of the CPU, An input port and an output port for inputting and outputting signals between them are provided (both not shown).

The following various sensors are connected to the input port of the electronic control unit 40 in order to detect the operating state of the internal combustion engine 10.
For example, the intake air temperature sensor 41 provided on the upstream side of the throttle valve 18 in the intake passage 13 detects the intake air temperature Ta, and the air flow meter 42 provided on the downstream side thereof detects the intake air amount Ga. A throttle sensor 43 provided in the vicinity of the throttle valve 18 in the intake passage 13 detects the opening degree of the throttle valve 18. Further, an EGR sensor 44 provided in the vicinity of the EGR valve 22 in the EGR passage 21 detects the opening degree of the EGR valve 22. In addition to these sensors, a rotation speed sensor 45 provided near the crankshaft 17 for detecting the engine rotation speed NE, a water temperature sensor 46 for detecting the cooling water temperature Tw of the internal combustion engine 10, and the operation are provided at the input port. An accelerator position sensor 47 or the like for detecting the amount of depression of an accelerator pedal (not shown) by the person is connected.

  The output port of the electronic control unit 40 is connected to drive circuits such as the fuel injection valve 15, the spark plug 16, the throttle motor 19, the EGR motor 23, and the actuator 32 described above. Then, the electronic control unit 40 grasps the operating state of the internal combustion engine 10 based on the detection signals input from the various sensors, and sends command signals to various driving circuits connected to the output port according to the grasped operating state. Is output. Thereby, fuel injection control for adjusting the injection amount and timing of the fuel supplied by the fuel injection valve 15, ignition timing control of the ignition plug 16, opening control of the throttle valve 18, and adjustment of the opening of the EGR valve 22 are adjusted. EGR control, opening / closing control of the TCV 30 and the like are performed.

  Specifically, as the EGR control, an EGR amount suitable for the engine operation state is set, and an opening degree of the EGR valve 22 that can recirculate the EGR amount is set as a target opening degree. The opening degree of the EGR valve 22 is adjusted so as to reach the target opening degree. Since the amount of EGR gas suitable for the engine operating state is recirculated to the intake passage 13, the opening of the throttle valve 18 is increased as compared with the case where the EGR gas is not recirculated, thereby reducing the pumping loss. As a result, fuel consumption can be improved.

  Here, the EGR gas recirculated to the intake passage 13 through the EGR passage 21 contains moisture generated by the combustion of the air-fuel mixture in the combustion chamber 12. Therefore, when the EGR gas is recirculated when the engine is cold, condensed water may be generated by cooling the EGR gas in the intake passage 13. Further, when the intake air flows through the intake passage 13 when the engine is cold and the intake air temperature Ta is 0 ° C. or less, the wall surface Tp is reduced to 0 ° C. or less by cooling the wall surface of the intake passage 13. May go down. Thus, if the EGR gas is recirculated when the wall surface temperature Tp of the intake passage 13 is 0 ° C. or less, the condensed water generated in the intake passage 13 may be frozen. Such condensed water tends to be generated particularly in the vicinity of the opening 21A of the EGR passage 21, which is a portion where EGR gas is first introduced into the intake passage 13. Furthermore, when the generation of such condensed water proceeds, the opening area around the opening 21A in the intake passage 13 may decrease or the blockage may occur.

  In addition, when the EGR gas is introduced into the combustion chamber 12, the combustion state of the air-fuel mixture may become unstable. In particular, when the engine is cold, the combustion state in the combustion chamber 12 is unstable. Therefore, when the EGR gas is recirculated into the intake passage 13 in such a state, the EGR gas is further introduced into the combustion chamber 12 due to the introduction of the EGR gas. There is concern about the deterioration of the combustion state.

  Therefore, in the present embodiment, in conjunction with the EGR control, the opening / closing control of the TCV 30 is executed to adjust the flow velocity of the intake air flowing through the intake passage 13 and adjust the strength of the tumble flow generated in the combustion chamber 12. I am doing so.

  Specifically, as shown in FIG. 3, when the engine is warm, an area where an amount of EGR gas set according to the engine operating state is introduced into the combustion chamber 12 is shown in FIG. An “EGR gas introduction area” is set. In this region, the EGR control is executed to introduce EGR gas into the combustion chamber 12.

  As a region in which the combustion state in the combustion chamber 12 is likely to become unstable with the introduction of such EGR gas, a “TCV closed region” shown in FIG. 3B is set. In this region, in addition to the adjustment of the opening degree of the EGR valve 22 described above, the position of the TCV 30 is controlled to the “warm closed position” indicated by the solid line in FIG. A stream is generated.

  It should be noted that the intake air amount is relatively large in the “EGR gas introduction region” and outside the “TCV closed region”, so even if no tumble flow is generated in the combustion chamber 12, the fuel and the air are mixed. It is well mixed and the combustion state is kept good. Therefore, the position of the TCV 30 is controlled to the “fully open position” indicated by the alternate long and short dash line in FIG. 2A, and the EGR control is executed to introduce EGR gas into the combustion chamber 12.

  On the other hand, as described above, particularly when the engine is cold, there is a concern about deterioration of the combustion state in the combustion chamber 12 and freezing of condensed water in the intake passage 13. Therefore, in the present embodiment, a “cold control adaptive region” shown in FIG. 3C is set. In this region, the cold control described below is executed, the EGR control is executed to introduce EGR gas into the combustion chamber 12, and the position of the TCV 30 is indicated by a chain line in FIG. Controlled to “cold position”.

  As shown in FIG. 2, the passage cross-sectional area Scold of the intake passage 13 when the TCV 30 is controlled to the “cold position during cold control” indicates that the TCV 30 is “closed when warm” when the engine is warm. It is controlled to be smaller than the passage sectional area Swarm of the intake passage 13 when it is controlled to “position” (Scold <Swarm). The passage sectional area Swarm of the intake passage 13 when the TCV 30 is controlled to the “warm closed position” is the passage breakage of the divided intake passage 13a formed on the opening 21A side of the EGR passage 21 in the intake passage 13. It is set to be substantially the same as the area Sa. Therefore, the passage cross-sectional area Scold of the intake passage 13 when the cold control is executed is controlled to be smaller than the passage cross-sectional area Sa of the divided intake passage 13a (Scol <Sa).

  Thus, when the TCV 30 is controlled to the “cold position when cold” and the passage cross-sectional area is reduced (Scold), the TCV 30 is controlled to the “close position when warm” when the engine is warm. Thus, the flow velocity in the vicinity of the opening 21A indicated by the arrow A in the intake passage 13 is increased. Therefore, even if condensed water is generated around the opening 21 </ b> A, it can be blown away with a strong air flow, and freezing of condensed water in the intake passage 13 can be suppressed. Further, since a stronger tumble flow is generated in the combustion chamber 12 than when the engine is warm, the intake air and the fuel are mixed well in the combustion chamber 12 and the combustion speed of these air-fuel mixtures increases. The combustion state becomes stable.

By the way, the “cold control adaptive region” is set as follows.
In the present embodiment, as described above, when the EGR gas is recirculated through the EGR passage 21, the opening degree of the throttle valve 18 is increased as compared with the case where the EGR gas is not recirculated. Is reduced.

  On the other hand, when the cold control is executed, the TCV 30 adjusts the passage cross-sectional area of the intake passage 13 to be small, so that the pumping loss is increased by the amount by which the cross-sectional area of the intake passage 13 is reduced. To come.

  Therefore, in order to improve fuel consumption, by comparing the reduction in pumping loss due to the opening of the throttle valve 18 and the increase in pumping loss due to the passage cross-sectional area being reduced by the TCV 30, It is desirable to execute the cold control in an engine operation state in which the pumping loss can be further reduced.

  Therefore, in the present embodiment, the region that is in the engine operating state in which the pumping loss is reduced with respect to the non-execution of the cold time control with the execution of the cold time control is preliminarily set as the “cold time control adaptive region”. The relationship between this area and the engine operating state is stored in the memory of the electronic control unit 40 as a map. As shown in FIG. 3, this map is set corresponding to the engine speed NE and the engine load.

  As a result, when the engine is cold and falls under the “cold control adaptive range”, when the EGR valve 22 is opened and the EGR control is executed, the TCV 30 is also in the “cold cold position”. Controlled. On the other hand, even when the engine is cold, if it does not fall within the “cold control adaptive range”, the EGR valve 22 is closed and EGR control is stopped, and the TCV 30 is also set to “fully open”. "Position" is controlled.

FIG. 4 shows the relationship between the cooling water temperature Tw and the wall surface temperature Tp and the execution region of the cold time control and the normal control.
As shown in FIG. 4, the region where the coolant temperature Tw is equal to or higher than the first predetermined temperature α (Tw ≧ α) and the wall surface temperature Tp is equal to or higher than the second predetermined temperature β (Tp ≧ β) Since this corresponds to the time when the engine warm-up of 10 is completed, normal control is executed.

  Note that the first predetermined temperature α is higher than “0 ° C.” and is a temperature at which it can be determined that freezing of condensed water is suppressed in the opening 21A of the EGR passage 21 (eg, “5 ° C.”). Is set.

Further, the second predetermined temperature β is set to a temperature (for example, “40 ° C.”) that can be determined that the combustion state of the air-fuel mixture in the combustion chamber 12 is stable.
Moreover, it is the area | region shown with the oblique line of the figure, Comprising: The area | region (Tw <(alpha)) where the cooling water temperature Tw is lower than 1st predetermined temperature (alpha), and the area | region (Tp <<) where wall surface temperature Tp is lower than 2nd predetermined temperature (beta). β) corresponds to a time when the engine is not warmed up and the engine is cold. In these regions, the cold control is executed when the engine operating state corresponds to the “cold control adaptive region”.

  As described above, in the present embodiment, by performing the cold time control, the freezing of the condensed water in the intake passage 13 and the deterioration of the combustion state in the combustion chamber 12 are suppressed, and the EGR gas is recirculated. The period during which fuel efficiency can be improved is expanded.

Next, with reference to FIG. 5, a procedure of processing executed by the electronic control device 40 will be described.
When this process is started, first, it is determined whether or not the wall surface temperature Tp is equal to or higher than the first predetermined temperature α (Tp ≧ α) (step S100). This wall surface temperature Tp is the wall surface temperature Tp around the opening 21A of the EGR passage 21 in the intake passage 13, and is estimated by the wall surface temperature estimation process executed in the electronic control unit 40. In this wall surface temperature estimation process, the intake air temperature Ta detected by the output signal of the intake air temperature sensor 41, the coolant temperature Tw detected by the output signal of the water temperature sensor 46, the elapsed time T after the start of the internal combustion engine 10, etc. Based on the above, the wall surface temperature Tp is estimated. This wall surface temperature estimation process corresponds to wall surface temperature estimation means. As described above, the condensed water tends to be generated around the opening 21A of the EGR passage 21, which is a portion where the EGR gas is first introduced into the intake passage 13, and therefore the wall surface around the opening 21A. The temperature Tp is estimated.

  If it is determined in step S100 that the wall surface temperature Tp is equal to or higher than the first predetermined temperature α (Tp ≧ α) (step S100: YES), the intake air is taken into account as the internal combustion engine 10 warms up. It can be determined that the wall surface temperature Tp around the opening 21A in the passage 13 has increased. In this case, even if the intake air temperature Ta flowing through the intake passage 13 is 0 ° C. or lower (Ta ≦ 0), the wall surface temperature Tp is increased as the wall surface temperature Tp increases as the internal combustion engine 10 warms up. 1 It can be determined that the temperature has risen to a predetermined temperature α or higher. In such a case, freezing of the condensed water in the intake passage 13 is suppressed.

  Therefore, when it is determined that the wall surface temperature Tp is equal to or higher than the first predetermined temperature α (Tp ≧ α) (step S100: YES), the cooling water temperature Tw is subsequently equal to or higher than the second predetermined temperature β. (Tw ≧ β) is determined (step S110). The cooling water temperature Tw is detected based on the output signal of the water temperature sensor 46.

  In step S110, when it is determined that the coolant temperature Tw is equal to or higher than the second predetermined temperature β (Tw ≧ β) (step S110: YES), the cooling is performed as the internal combustion engine 10 is warmed up. It can be determined that the water temperature Tw has risen and the combustion state has stabilized in the combustion chamber 12.

  Thus, when it is determined that the cooling water temperature Tw is equal to or higher than the second predetermined temperature β (Tw ≧ β) (step S110: YES), the wall surface temperature Tp is equal to or higher than the first predetermined temperature α (Tp ≧ α). (Step S100: YES) Since the coolant temperature Tw is equal to or higher than the second predetermined temperature β (Tw ≧ β) (Step S110: YES), it is determined that the internal combustion engine 10 has been warmed up. Therefore, normal control is executed (step S120), and this process is terminated. When this normal control is executed, if it is determined that the engine operating state corresponds to either the “EGR gas introduction region” or the “TCV closed region” shown in FIG. The EGR valve 22 and the TCV 30 are controlled. Note that if the cold control has already been executed when an affirmative determination is made in step S110, the cold control is stopped by executing the normal control.

  On the other hand, when it is determined in step S100 that the wall surface temperature Tp is lower than the first predetermined temperature α (Tp <α) (step S100: NO), the condensed water is frozen in the intake passage 13 as described above. There is a concern to do.

  Further, when it is determined in step S110 that the coolant temperature Tw is lower than the second predetermined temperature β (Tw <β) (step S110: NO), as described above, combustion occurs with the introduction of the EGR gas. There is a concern that the combustion state of the air-fuel mixture deteriorates in the chamber 12.

  Therefore, if a negative determination is made in any of these steps S100 and S110, it is determined that the internal combustion engine 10 has not been warmed up and that the engine is cold. Accordingly, it is subsequently determined whether or not it is the “cold control adaptive region” (step S130).

  This determination process is determined based on the engine speed NE and the engine load by referring to the map shown in FIG. 3 stored in the electronic control unit 40. The processing in this step corresponds to “determination means” for determining that the engine operating state is such that the pumping loss is reduced when the cold control is not performed when the cold control is performed when the engine is cold. .

As a result, when it is determined that it is the “cold control adaptive region” (step S130: YES), the cold control is executed.
That is, the position of the TCV 30 is controlled to the “cold closed position” (step S140). As a result, a stronger tumble flow is generated in the combustion chamber 12 and a stronger air flow is generated in the intake passage 13 than when the engine is warmed to the “warm closed position”.

  Then, the EGR valve 22 is opened (step S150), and EGR control is executed. Thereby, EGR gas is introduced into the combustion chamber 12. As a result, this process is terminated.

  On the other hand, when it is determined that it is not the “cold control adaptive region” (step S130: NO), it is assumed that the opening degree of the throttle valve 18 is increased by recirculating the EGR gas to the intake passage 13. However, it is determined that the pumping loss is increased by controlling the TCV 30 to the “cold closed position”.

  Therefore, in this case, the cold control is not executed, the position of the TCV 30 is controlled to the “fully open position” (step S160), and the EGR valve 22 is closed (step S170). Thereby, since the recirculation of EGR gas is stopped, the deterioration of the combustion state due to the introduction of EGR gas into the combustion chamber 12 can be suppressed. This process is thus completed.

  If it is determined in step S130 that it is the “cold control adaptive region” and the cold control is executed, an affirmative determination is made in steps S100 and S110 in this process that is executed again. Sometimes, it is determined that the internal combustion engine 10 has been warmed up. And normal control is performed at this time (step S120), and cold time control is stopped by this.

Next, the states of the EGR valve 22 and the TCV 30 set through the execution of the cold time control and the normal control in the present embodiment will be described with reference to FIG.
FIG. 6 shows an example in which the internal combustion engine 10 is started at time t1 and the warm-up of the internal combustion engine 10 is completed at time t3.

  First, after the internal combustion engine 10 is started at time t1, the engine is cold and the engine operation state does not correspond to the “cold control adaptive region” (“No”) (from time t1 to time t2). Until cold), the cold control is not executed. In this case, the EGR valve 22 is closed and the TCV 30 is controlled to the “fully open position”.

  Next, at the time t2, when the engine operation state corresponds to the “cold control adaptive region” (“positive”), the cold control is executed. In this case, the EGR valve 22 is opened and the TCV 30 is controlled to the “cold closed position”.

  Next, when the warm-up of the internal combustion engine 10 is completed at time t3, normal control is executed. From time t3 to time t4, since the engine operating state corresponds to the “TCV closed region”, the EGR valve 22 is opened and the TCV 30 is controlled to the “warm closed position”. Further, after the time t4, the engine operating state falls within the “EGR gas introduction region” and falls outside the “TCV closed region”, so the EGR valve 22 is opened and the TCV 30 is “ It is controlled to the “fully open position”.

According to 1st Embodiment described above, there can exist the following effects.
(1) When the EGR gas is recirculated through the EGR passage 21 when the engine is cold, the passage sectional area Scold of the intake passage 13 is made smaller than the passage sectional area Swarm of the intake passage 13 when the engine is warm. (Scold <Swarm), the TCV 30 is controlled. As a result, when the engine is cold, the flow velocity of the intake air flowing through the intake passage 13 is faster than when the engine is warm, so that the condensed water generated in the intake passage 13 can be blown off with a strong air flow. Freezing of condensed water in the passage 13 can be suppressed. Further, by controlling the TCV 30 as described above, a stronger vortex flow (tumble flow) is generated in the combustion chamber 12 than when the engine is warm. Therefore, even when the EGR gas is recirculated when the engine is cold, where the combustion state tends to be more unstable than when the engine is warm, the mixture of intake air and fuel is mixed well and the combustion speed is reduced. It can be raised and the combustion state can be stabilized. Therefore, according to the present embodiment, the period during which the EGR gas can be recirculated through the EGR passage 21 while suppressing the freezing of the condensed water in the intake passage 13 and the deterioration of the combustion state in the combustion chamber 12 is extended until the engine is cold. It becomes possible to enlarge (FIG. 4). Accordingly, it is possible to suitably set a period for recirculating the EGR gas for the purpose of improving fuel consumption.

  (2) When it is determined that the wall surface temperature Tp is equal to or higher than the first predetermined temperature α (Tp ≧ α) and the cooling water temperature Tw is equal to or higher than the second predetermined temperature β (Tp ≧ β), the cold time control is performed. Is stopped (step S120). Accordingly, it is possible to suppress the execution period of the cold time control for suppressing the freezing of the condensed water in the intake passage 13 and the deterioration of the combustion state in the combustion chamber 12 from becoming unnecessarily long.

  (3) It is determined that the engine operating state (cold control adaptive region) is reduced when the engine is cold and the pumping loss is reduced when the cold control is not executed. When this is done (step S130: YES), cold time control is executed (steps S140, S150). That is, the cold time control is executed in a suitable period for executing the cold time control. Therefore, fuel efficiency can be effectively improved.

  (4) Even when the engine is cold, if the engine operating state does not correspond to the cold control adaptive region (step S130: NO), the cold control is not executed, and the exhaust through the EGR passage 21 is not performed. The recirculation is stopped (steps S160 and S170). That is, when it is determined that the engine operating state is such that the pumping loss is not reduced even if the above-described cold control is executed when the engine is cold, pumping is performed by controlling the TCV 30 to the “cold closed position”. The increase in loss is avoided. As a result, when the engine is cold, the pumping loss can be suitably reduced according to the operating state of the internal combustion engine 10, and the fuel consumption can be improved more effectively.

  (5) Since the partition wall 33 is disposed in the intake passage 13, the intake air is drifted by adjusting the passage cross-sectional area of the intake passage 13 by the TCV 30, and the drifted intake air flows along the partition wall 33. It can be sent to the combustion chamber 12 side. Therefore, a good tumble flow can be generated in the combustion chamber 12 by the TCV 30 and the partition wall 33, and the combustion state can be stabilized more effectively in the combustion chamber 12.

  (6) Since the partition wall 33 is disposed so as to oppose the opening portion 21A of the EGR passage 21 in the intake passage 13, the intake air that is drifted by the TCV 30 to increase the flow velocity is formed along the partition wall 33 with the opening portion 21A. Pass through the surroundings. Therefore, it is possible to suppress the generation of condensed water around the opening 21A that tends to generate condensed water, or to remove the generated condensed water. Therefore, it becomes possible to more effectively suppress the freezing of condensed water.

(Second Embodiment)
Next, a second embodiment that embodies the control device for an internal combustion engine according to the present invention will be described with reference to FIGS. 7 and 8, focusing on the differences from the first embodiment.

In the first embodiment, the partition wall 33 is disposed in the intake passage 13. However, in the present embodiment, as illustrated in FIG. 7, the partition wall is not disposed in the intake passage 13.
In the first embodiment, it is determined that the wall surface temperature Tp is equal to or higher than the first predetermined temperature α (Tp ≧ α) and the cooling water temperature Tw is equal to or higher than the second predetermined temperature β (Tw ≧ β). Sometimes, it is determined that the warm-up of the internal combustion engine 10 has been completed, and the cold control is stopped. In contrast, in the present embodiment, when it is determined that the wall surface temperature Tp is equal to or higher than the first predetermined temperature α (Tp ≧ α), the cold control is stopped.

Next, with reference to FIG. 8, a procedure of processing executed by the electronic control device 40 in the present embodiment will be described.
When the internal combustion engine 10 is started and this process is started, it is first determined whether or not the engine is cold (step S200). Specifically, whether or not the engine is cold is determined based on the intake air temperature Ta detected by the intake air temperature sensor 41 and the coolant temperature Tw detected by the water temperature sensor 46. For example, the intake air temperature Ta is 0 ° C. or less (Ta ≦ 0), and there is a concern that the water in the EGR gas freezes in the intake passage 13, and the cooling water temperature Tw is less than the second predetermined temperature β. (Tw <β) When it is feared that the combustion state in the combustion chamber 12 becomes unstable, it is determined that the engine is cold.

If it is determined that the engine is not cold (step S200: NO), normal control is executed (step S250), and the process is terminated.
On the other hand, when it is determined that the engine is cold (step S200: YES), it is subsequently determined whether the engine is in the “cold control adaptive region” (step S210). The determination process in this step is the same as the determination process in step S130.

  And when it determines with it being "a cold control adaptation area | region" (step S210: YES), the cold control is performed. That is, the TCV 30 is controlled to the “cold closed position” (step S220), and the EGR valve 22 is opened (step S230).

  Next, it is determined whether or not the wall surface temperature Tp is equal to or higher than the first predetermined temperature α (Tp ≧ α) (step S240). This determination process is the same as the determination process in step S100.

  When it is determined by this determination process that the wall surface temperature Tp is equal to or higher than the first predetermined temperature α (Tp ≧ α) (step S240: YES), normal control is executed (step S250), and this process is performed. Is terminated.

  On the other hand, when it is determined that it is not the “cold control adaptive region” (step S210: NO), the cold control is not executed and the TCV 30 is controlled to the “fully open position” (step S260). The EGR valve 22 is closed (step S270), and the processes from step S210 are executed again.

  Even when it is determined in step S240 that the wall surface temperature Tp is lower than the first predetermined temperature α (Tp <α) (step S240: NO), the processing from step S210 is executed again.

  If an affirmative determination is made in step S240 through such determination processing (step S240: YES), normal control is executed (step S250). As a result, the cold control is stopped and the present process is terminated.

According to the second embodiment described above, the following operational effects can be obtained in addition to the operational effects described in (1), (3), and (4) above.
(7) It is determined based on the wall surface temperature Tp whether or not the condensate is frozen, and when the wall surface temperature Tp around the opening 21A is equal to or higher than the first predetermined temperature α (Tp ≧ α). ), Cold control is stopped. Therefore, it is possible to suppress the execution period of the cold control for the purpose of suppressing the freezing of the condensed water from becoming longer than necessary.

(Other embodiments)
Note that the control device for an internal combustion engine according to the present invention is not limited to the configuration exemplified in each of the above-described embodiments, and may be implemented as, for example, the following forms in which those embodiments are appropriately changed.

  In the first embodiment, the example in which the determination process (step S110) related to the cooling water temperature Tw is executed after the determination regarding the determination process (step S100) related to the wall surface temperature Tp is made is shown. You may change suitably about.

  In the first embodiment, an example (steps S100 and S110) in which it is determined that the engine is cold is shown based on the wall surface temperature Tp and the cooling water temperature Tw. However, as in the determination process in step S200 in the second embodiment, it is determined that the engine is cold based on the intake air temperature Ta and the cooling water temperature Tw, and thereby the cold time control is started. It may be. Then, when it is determined that the wall surface temperature Tp is equal to or higher than the first predetermined temperature α (Tp ≧ α) and the cooling water temperature Tw is equal to or higher than the second predetermined temperature β (Tw ≧ β), the cold time control is performed. By stopping the operation, the effects shown in the above (1) to (6) can be achieved.

  In the first embodiment, the example in which the partition wall 33 is disposed so as to face the opening portion 21A of the EGR passage 21 has been described. However, the partition wall is disposed without facing the opening portion 21A. You may do it. Even in this case, the effects shown in the above (1) to (5) can be achieved.

  In the first embodiment, the passage cross-sectional area Swarm of the intake passage 13 when the TCV 30 is controlled to the “closed position during warm” when the engine is warm is equal to the divided intake passage 13a formed by the partition wall 33. An example (Swarm = Sa) that is substantially the same as the passage cross-sectional area Sa is shown. However, the “warm closed position” of the TCV 30 is an example, and may be appropriately changed in consideration of the generation state of the tumble flow in the combustion chamber 12. In short, the passage cross-sectional area Swarm when the TCV 30 is controlled is set to have such a size that a tumble flow is satisfactorily generated in the combustion chamber 12, thereby the above (1) to (6 The effects shown in FIG.

  In each of the above embodiments, the TCV 30 is controlled in three stages of “fully open position”, “warm closed position”, and “cold closed position”. However, such a tumble control may be configured so that its position can be changed steplessly. Even in this case, the passage sectional area of the intake passage 13 when the engine is cold is controlled so as to be smaller than the passage sectional area of the intake passage 13 when the engine is warm. The effect shown to (7) can be show | played.

  In each of the above embodiments, the tumble control valve is configured by a single TCV 30 and the rotation shaft 31 of the TCV 30 is fixed to the intake passage 13 at a position separated from the partition wall 33. However, the configuration of such a tumble control valve and its fixed position can be changed as appropriate. For example, as shown in FIG. 9, a plurality of valve bodies, such as a valve body 60 pivotally supported on the intake passage 13 by a rotation shaft 61 and a valve body 70 pivotally supported on the intake passage 13 by a rotation shaft 71, are tumbled. A control valve may be configured. That is, the rotation shaft 61 of the valve body 60 is disposed at the same position as in the above embodiments, but the rotation shaft 71 of the valve body 70 is disposed in the vicinity of the partition wall 33. Even in this case, the same effect as described above can be obtained by controlling the valve body 60 and the valve body 70 as follows. When the engine is warm, the valve body 60 and the valve body 70 are respectively controlled to the “warm closed position” indicated by the solid line in FIG. When the engine is cold, the valve body 60 is controlled to the position indicated by the solid line in FIG. 5B (the same position as the “closed position during warm”), and the valve body 70 is indicated by the chain line in FIG. It is controlled to the “cold closing position” shown. Further, when the tumble control valve is controlled to the “fully opened position”, the valve body 60 is controlled to the “fully opened position” indicated by the alternate long and short dash line in FIG. 9A, and the valve body 70 is indicated by the solid line in FIG. It is controlled to the position shown (the same position as the “warm closed position”).

  Further, the tumble control valve may be configured as a valve body 80 and a rotation shaft 81 shown in FIG. 10 instead of the valve body 60 and the rotation shaft 61 shown in FIG. Even in this case, the valve body 70 and the valve body 80 are each controlled to the same position as in FIG.

  In each of the above embodiments, an example in which a tumble control valve (TCV) 30 that generates a tumble flow in the combustion chamber 12 is provided as an airflow control valve has been described. On the other hand, a swirl control valve that generates a swirl flow in the combustion chamber 12 may be provided as an air flow control valve. Even in this case, when the EGR gas is recirculated when the engine is cold, the swirl so that the passage cross-sectional area of the intake passage at that time becomes smaller than the cross-sectional area of the intake passage when the engine is warm. By controlling the control valve, at least the above-described operational effect (1) can be achieved.

  In each of the above embodiments, the example in which the wall surface temperature Tp is estimated by executing the wall surface temperature estimation process in the electronic control unit 40 has been described. However, as shown in FIG. 11, the wall surface temperature Tp may be directly detected by providing a wall surface temperature sensor 48 that outputs a signal corresponding to the wall surface temperature Tp of the intake passage 13 as the wall surface temperature estimating means. Furthermore, the wall surface temperature Tp around the opening 21A may be estimated based on the output signal of the wall surface temperature sensor.

  In each of the above-described embodiments, the example in which the in-cylinder injection type fuel injection valve 15 that supplies the fuel into the combustion chamber 12 of the internal combustion engine 10 is shown. However, as shown in FIG. 11, a port injection type fuel injection valve 56 that supplies fuel into the intake passage 13 may be provided.

  In each of the above embodiments, the internal combustion engine 10 is a gasoline engine, but the present invention may be applied to a diesel engine. In such a diesel engine, there is a configuration in which the throttle valve 18 as described above is not provided, but even in this case, the operational effects shown in the above (1), (2), and (7) are achieved. be able to.

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... Piston, 12 ... Combustion chamber, 13 ... Intake passage, 13a, 13b ... Split intake passage, 14 ... Exhaust passage, 15, 56 ... Fuel injection valve, 16 ... Spark plug, 17 ... Crankshaft, 17a ... connecting rod, 18 ... throttle valve (intake air amount adjustment valve), 20 ... EGR device (exhaust gas recirculation device), 21 ... EGR passage (exhaust gas recirculation passage), 21A ... opening, 22 ... EGR valve, 23 ... EGR motor, 30 ... Tumble control valve (airflow control valve), 31, 61, 71, 81 ... Rotating shaft, 32 ... Actuator, 33 ... Bulkhead, 40 ... Electronic control device, 41 ... Intake temperature sensor, 42 ... Air flow meter 43 ... Throttle sensor, 44 ... EGR sensor, 45 ... Rotational speed sensor, 46 ... Water temperature sensor (water temperature detection means), 47 ... Accelerator positive Yonsensa, 48 ... wall temperature sensor (wall temperature estimating means) 60, 70, 80 ... valve body.

Claims (9)

An exhaust gas recirculation device that recirculates part of the exhaust gas to the intake passage through an exhaust gas recirculation passage that connects the intake passage and the exhaust passage of the internal combustion engine, and a cross-sectional area of the intake passage provided in the intake passage. In a control device for an internal combustion engine comprising an airflow control valve that generates a vortex flow in the combustion chamber of the engine by adjusting,
When the engine is cold, when the exhaust gas is recirculated through the exhaust gas recirculation passage, the air flow control is performed so that the passage sectional area of the intake passage is smaller than the passage sectional area of the intake passage when the engine is warm. A control apparatus for an internal combustion engine, characterized by executing cold control for controlling a valve. The control apparatus for an internal combustion engine according to claim 1,
Wall surface temperature estimating means for estimating the wall surface temperature around the opening of the exhaust gas recirculation passage in the intake passage;
The control apparatus for an internal combustion engine, wherein the cold-time control is stopped when the wall surface temperature estimated based on the wall surface temperature estimating means is equal to or higher than a predetermined temperature higher than zero degrees. The control apparatus for an internal combustion engine according to claim 2,
A water temperature detecting means for detecting the cooling water temperature of the engine;
A second predetermined value in which the wall surface temperature estimated based on the wall surface temperature estimating means is equal to or higher than a predetermined temperature higher than zero degrees and the cooling water temperature detected by the water temperature detecting means is determined to stabilize the combustion state in the combustion chamber. The control apparatus for an internal combustion engine, wherein the cold control is stopped when the temperature is equal to or higher than a temperature. The control device for an internal combustion engine according to any one of claims 1 to 3,
An intake air amount adjustment valve for adjusting the amount of intake air flowing through the intake passage is disposed upstream of the airflow control valve in the intake passage,
A determination means for determining that the engine is in an engine operating state in which a pumping loss is reduced with respect to a non-execution of the cold time control when the cold time control is executed when the engine is cold;
The control apparatus for an internal combustion engine, wherein the cold time control is executed when it is determined by the determination means that the engine operating state is such that a pumping loss is reduced. The control apparatus for an internal combustion engine according to claim 4,
When it is determined by the determination means that the engine operating state does not reduce the pumping loss, the cross-sectional area of the intake passage by the airflow control valve is set to a fully open state, and the exhaust gas recirculation through the exhaust recirculation passage is set. A control device for an internal combustion engine, characterized by stopping circulation. The control apparatus for an internal combustion engine according to any one of claims 1 to 5,
The control device for an internal combustion engine, wherein the airflow control valve is a tumble control valve that generates a tumble flow in the combustion chamber. The control apparatus for an internal combustion engine according to claim 6,
A control device for an internal combustion engine, wherein a partition that divides the internal space of the intake passage into a plurality of divided intake passages along an axis of the intake passage is disposed in the intake passage. The control apparatus for an internal combustion engine according to claim 7,
The passage cross-sectional area of the intake passage adjusted by the airflow control valve when the engine is warm is a division formed on the opening side of the exhaust gas recirculation passage in the intake passage among the plurality of divided intake passages. It is set to be approximately the same as the cross-sectional area of the intake passage,
The control device for an internal combustion engine, wherein the airflow control valve is adjusted so that a passage sectional area of the intake passage is smaller than a sectional area of the divided intake passage during execution of the cold time control. . The control apparatus for an internal combustion engine according to claim 7 or 8,
The control apparatus for an internal combustion engine, wherein the partition wall is disposed so as to face an opening portion of the exhaust gas recirculation passage in the intake passage.

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