JP2009167932A - Internal combustion engine control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal combustion engine control device which can control the lowering of a temperature of a catalyst while preventing melting damage at fuel cut. <P>SOLUTION: An engine system is provided with a first air suction pathway 10a that leads outside air outside an engine room where an engine 60 is stored into the engine 60 as suction air, a second air suction pathway 10b that leads inner air inside the engine room to the engine 60, a switching valve 15 which selectively switches the connection of the first air suction pathway 10a and the second air suction pathway 10b, and an ECU 90 which executes air suction temperature raising processing that controls the switching valve 15 so that the second air suction pathway 10b is in a connected state at the fuel cut. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  2. Description of the Related Art Conventionally, a technique is known in which a canister adsorbs evaporated fuel in a fuel tank and purges the evaporated fuel adsorbed by the canister to an intake system of an internal combustion engine. Patent Document 1 discloses a technique for purging the evaporated fuel adsorbed by a canister when a fuel cut is performed. According to this technique, the evaporated fuel is purged into the intake system at the time of fuel cut, so that the temperature drop of the catalyst accompanying the fuel cut can be suppressed. By suppressing the temperature drop of the catalyst, it is possible to prevent the exhaust emission from deteriorating when the fuel supply is restored.

JP-A-5-248316 JP 2005-299628 A JP 2007-170251 A Japanese Patent Laid-Open No. 2003-083181 JP 2006-307770 A JP-A-11-062662

  However, according to the technique disclosed in the above-mentioned patent document, if the temperature of the catalyst immediately before the fuel cut is near the upper limit of the allowable temperature, or if the dilution ratio of the fuel into the engine oil is high, the evaporation By purging the fuel into the intake system, the catalyst may become hotter than expected. When the temperature of the catalyst becomes higher than the allowable temperature, the catalyst may be melted.

  Accordingly, an object of the present invention is to provide a control device for an internal combustion engine capable of suppressing temperature drop of a catalyst while preventing melting damage at the time of fuel cut.

  An object of the present invention is to provide a control device for an internal combustion engine comprising a catalyst for purifying exhaust gas of the internal combustion engine, and a fuel cut means for cutting the supply of fuel to the internal combustion engine when a predetermined condition is satisfied. A first intake passage for leading outside air outside the engine room as intake air to the internal combustion engine, a second intake passage for guiding inside air inside the engine chamber as intake air to the internal combustion engine, and communication between the first and second intake passages are selected. Control of the internal combustion engine, comprising: switching means for switching automatically; and catalyst temperature-decreasing control means for performing intake air temperature raising processing for controlling the switching means so as to bring the second intake passage into a communicating state at the time of fuel cut Can be achieved by equipment.

  Generally, the inside air in the engine room is hotter than the outside air outside the engine room. Therefore, by setting the second intake passage in the communication state at the time of fuel cut, the temperature drop of the catalyst at the time of fuel cut can be suppressed. Moreover, it is unlikely that the inside air in the engine room will reach such a high temperature that the catalyst is melted, no matter how high the temperature is. For this reason, even if it is a case where such a process is performed, a catalyst does not melt. Therefore, the temperature drop of the catalyst can be suppressed while preventing the catalyst from being melted.

  The above object is also achieved in an internal combustion engine control device comprising a catalyst for purifying exhaust gas of the internal combustion engine and fuel injection control means for cutting off the supply of fuel to the internal combustion engine when a predetermined condition is satisfied. A bypass passage bypassing the supercharger to be supplied, opening and closing means for opening and closing the bypass passage, and a part of the intake air supercharged by the supercharger at the time of fuel cut is returned to the supercharger again This can also be achieved by a control device for an internal combustion engine, comprising a catalyst temperature drop control means for performing intake air temperature raising processing for controlling the opening / closing means.

  When a part of the supercharged intake air is supercharged again, a part of the intake air is compressed and the temperature rises. The intake air can be raised in temperature by such processing.

  In the above configuration, the apparatus includes a catalyst temperature acquisition unit that acquires the temperature of the catalyst, and the catalyst temperature decrease control unit determines whether or not to execute the intake air temperature increase process according to the acquired temperature of the catalyst. Can be adopted. For example, when the temperature of the catalyst exceeds an upper limit temperature at which the catalyst does not melt or close to the upper limit temperature, the catalyst can be prevented from being melted by not performing the catalyst temperature decrease suppression process.

  In the above configuration, it is possible to employ a configuration that includes an intake air temperature acquisition unit that acquires an intake air temperature, and the catalyst temperature decrease control unit determines whether or not to execute the intake air temperature increase process according to the acquired intake air temperature. .

  In the above configuration, the catalyst temperature drop control means can execute an exhaust stroke injection process in which fuel injection is performed in an exhaust stroke at the time of fuel cut, and when the acquired catalyst temperature is relatively high, When the temperature raising process is relatively low, the exhaust stroke injection process can be alternatively executed.

  When the temperature of the catalyst is relatively low, the intake air temperature raising process alone is not sufficient to suppress the temperature drop of the catalyst. Therefore, when the catalyst temperature is relatively low, the exhaust stroke injection process is performed. By executing, the temperature of the catalyst can be raised.

  In the above configuration, the catalyst temperature drop control means can execute a purge process for purging the evaporated fuel in the fuel tank to the intake system when the fuel is cut, and when the obtained catalyst temperature is relatively high. Can adopt a configuration in which the intake air temperature raising process is executed selectively, and if the temperature is relatively low, the purge process is executed alternatively. Even with this configuration, the temperature of the catalyst can be raised by executing the purge process when the temperature of the catalyst is relatively low.

  ADVANTAGE OF THE INVENTION According to this invention, the control apparatus of the internal combustion engine which can suppress the temperature fall of a catalyst can be provided, preventing a melting loss at the time of fuel cut.

  FIG. 1 is a configuration diagram of an engine system according to the first embodiment. The engine system according to the first embodiment includes a first intake passage 10a, a second intake passage 10b, an intercooler 12, a surge tank 13, an exhaust passage 20, a fuel tank 30, a turbocharger 40, an engine (internal combustion engine) 60, a catalyst. 80, ECU (electronic control unit) 90, and the like.

  The ECU 90 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and controls the operation of the entire engine system. Further, it is configured to be able to execute processing to be described later in accordance with a control program stored in the ROM. In addition, the RAM is configured to temporarily store various data acquired in the course of processing to be described later. The ECU 90 corresponds to a fuel cut unit that cuts the supply of fuel to the engine 60 when a predetermined condition is satisfied. The ECU 90 corresponds to a catalyst temperature drop control means, which will be described later in detail.

  The fuel stored in the fuel tank 30 is accumulated in a high pressure state on the common rail 62 via the delivery pipe 61 by the fuel pump 31. The fuel accumulated in the common rail 62 is directly injected into each cylinder 64 by the injector 63.

  Further, the fuel tank 30 is provided with a purge device for allowing the evaporated fuel generated from the fuel stored in the fuel tank 30 to escape to the intake system. The purge device includes an evaporated fuel passage 32, a canister 33, a purge passage 34, a purge valve 35, and the like. The evaporated fuel generated in the fuel tank 30 is temporarily stored in the canister 33, and the purge valve 35 is opened during the start of the engine 60, so that it is sucked into the first intake passage 10a by the negative intake pressure and purge processing is performed. Is made.

  The engine system also includes an intake air temperature sensor 71 that detects the temperature of the intake air that is guided to the engine 60, an outside air temperature sensor 72 that detects the outside air temperature, and a catalyst temperature sensor 73 that detects the temperature of the catalyst 80. The detection signal is output to the ECU 90. Although not shown, the intake air temperature sensor 71 is on the downstream side of the intercooler 12 and on the downstream side of the junction between the first intake passage 10a and the second intake passage 10b. Arranged in the intake passage 10a. Thus, the intake air temperature sensor 71 can detect the intake air temperature in either case where outside air is introduced into the engine 60 as intake air or inside air is introduced.

  Note that the engine system according to the present embodiment includes the catalyst temperature sensor 73 that detects the temperature of the catalyst 80. However, the present invention is not limited to such a configuration. You may comprise so that the information regarding the temperature of the catalyst 80 may be acquired by estimating temperature.

  When intake air is introduced from the first intake passage 10 a, the intake air is pressurized by the compressor 41 and guided to the engine 60. The intake air guided to the engine 60 is combusted together with fuel in the cylinder 64 and is discharged into the exhaust passage 20 as exhaust. The exhaust is sent to the turbine 42 and then to the catalyst 80.

  As shown in FIG. 1, the engine system according to the present embodiment is provided with a first intake passage 10a and a second intake passage 10b. The first intake passage 10a is configured to guide outside air outside the engine room (engine room) to the engine 60 as intake air. The second intake passage 10b is configured to guide the inside air in the engine room to the engine 60 as intake air. The intake inlet of the second intake passage 10b is open in the engine room, and introduces air around the equipment that is relatively hot in the engine room into the engine 60 as the intake air during startup of the engine 60. For example, the inlet of the second intake passage 10b may be in the vicinity of the catalyst 80, may be behind a radiator (not shown), or may be behind the intercooler 12. The said position is a position where the surrounding air becomes comparatively high temperature in an engine room. In addition, when the introduction port of the second intake passage 10b is arranged behind the radiator, the traveling wind that escapes from the front to the rear of the radiator receives the heat from the radiator and rises in temperature. Can be introduced as intake. The same applies to the case where the inlet of the second intake passage 10b is arranged behind the intercooler 12.

  In addition, a switching valve 15 capable of switching the intake air introduced into the engine 60 to either the outside air or the inside air is disposed at a joining portion of the first intake passage 10a and the second intake passage 10b. Specifically, the switching valve 15 alternatively places one of the first intake passage 10a and the second intake passage 10b in a communication state. The operation of the switching valve 15 is controlled in accordance with a command from the ECU 90. Therefore, when the switching valve 15 is in communication with the first intake passage 10a, outside air is introduced into the engine 60 as intake air, whereas the switching valve 15 is in communication with the second intake passage 10b. The inside air is introduced into the engine 60 as intake air. The switching valve 15 corresponds to switching means.

  Next, the relationship among the temperature of the catalyst 80, the inside air temperature, and the outside air temperature after the engine 60 is started will be described. FIG. 2 is a graph showing the relationship between the temperature of the catalyst 80, the inside air temperature, and the outside air temperature. As shown in FIG. 2, after the engine 60 is started, the catalyst 80 becomes a high temperature of 200 to 300 ° C. or higher after a predetermined period. On the other hand, the inside air temperature rises gently with the operation of each device arranged in the engine room. The outside air temperature is constant regardless of the start of the engine 60. As shown in FIG. 2, the difference between the temperature of the catalyst 80 and the outside air temperature increases as time elapses after the engine 60 is started.

  Therefore, as will be described in detail later, when the outside air having a low temperature is supplied to the engine 60 as intake air when the fuel is cut, the catalyst 80 may be cooled. When the catalyst 80 is cooled, when the fuel injection is restored, the catalyst 80 becomes less than the activation temperature, and the exhaust emission may be deteriorated. Further, if the purge process is executed when the fuel is cut, the evaporated fuel is combusted in the catalyst 80 and the temperature of the catalyst 80 rises excessively. Depending on the temperature of the catalyst 80 just before the fuel cut, the catalyst 80 may be melted. is there. In order to solve the above problems, the ECU 90 executes the following processing.

  FIG. 3 is a flowchart illustrating an example of processing executed by the ECU 90. This process is repeatedly executed at a predetermined cycle. As shown in FIG. 3, the ECU 90 determines whether or not a fuel cut that cuts off the fuel supply to the engine 60 is executed (step S <b> 1). The fuel cut is executed, for example, during deceleration, and the fuel supply is restored when the engine speed has decreased to a predetermined speed. In the case of a negative determination, the ECU 90 ends this process.

  If the determination is affirmative, the ECU 90 determines whether the temperature of the catalyst 80 is equal to or lower than the allowable temperature based on the output from the catalyst temperature sensor 73 (step S2). The allowable temperature is an upper limit temperature at which the catalyst 80 is not likely to melt. When the temperature of the catalyst 80 is equal to or lower than the allowable temperature, the ECU 90 executes intake air temperature increase control (step S3). When it is determined that the temperature of the catalyst 80 exceeds the allowable temperature, intake air temperature lowering control is executed (step S4).

  Next, intake air temperature rise control will be described. FIG. 4 is a flowchart showing an example of intake air temperature rise control executed by the ECU 90. As shown in FIG. 4, the ECU 90 determines whether or not the intake air temperature is equal to or lower than the outside air temperature based on the outputs from the intake air temperature sensor 71 and the outside air temperature sensor 72 (step S31). If the determination is negative, this process ends. If the determination is affirmative, the ECU 90 controls the switching valve 15 so that the inside air is introduced into the engine 60 (step S32). That is, the ECU 90 controls the operation of the switching valve 15 so that the second intake passage 10b is in a communication state. As a result, the engine 60 is introduced into the engine 60 with the inside air having a higher temperature than the outside air.

  FIG. 5 is a graph comparing the temperature of the catalyst 80 and the temperature of the intake air when the intake air temperature rise control is executed and when it is not executed. As shown in FIG. 5, when the fuel cut is executed, the temperature of the catalyst 80 decreases. However, when the intake air temperature increase control is executed and when it is not executed, the catalyst is more effective when the fuel cut is executed. It can be seen that the temperature drop of 80 is suppressed.

  The reason for this is that when the intake air temperature rise control is not executed, the intake air introduced into the engine 60 is outside air, so that the temperature decrease of the catalyst 80 is promoted, whereas the intake air introduced into the engine 60 is not In the case of inside air, the temperature drop of the catalyst 80 is suppressed. Thus, ECU90 suppresses the temperature fall of the catalyst 80 at the time of fuel cut. Further, no matter how high the inside air is, it is unlikely that the temperature will be high enough to cause the catalyst 80 to melt. For this reason, even if it is a case where such a process is performed, the catalyst 80 does not melt. Therefore, the temperature drop of the catalyst 80 can be suppressed while preventing the catalyst 80 from melting.

  Next, intake air temperature reduction control executed by the ECU 90 will be described. FIG. 6 is a flowchart illustrating an example of intake air temperature decrease control executed by the ECU 90. As shown in FIG. 6, the ECU 90 determines whether the intake air temperature is equal to or lower than the outside air temperature based on the outputs from the intake air temperature sensor 71 and the outside air temperature sensor 72 (step S41). If the intake air temperature is lower than the outside air temperature, the ECU 90 ends this process. This is because the intake air temperature cannot be lowered further.

  When the intake air temperature exceeds the outside air temperature, the ECU 90 controls the switching valve 15 so that the outside air is introduced into the engine 60 (step S42). That is, the ECU 90 controls the operation of the switching valve 15 so that the first intake passage 10a is in a communication state. Thereby, when the intake air temperature exceeds the outside air temperature, the outside air having a temperature lower than the inside air is introduced into the engine 60 as the intake air. That is, the case where the intake air temperature exceeds the outside air temperature may occur when the inside air is introduced into the engine 60 as the intake air. Therefore, in the intake air temperature lowering control, the outside air is introduced as the intake air, thereby dissolving the catalyst 80. Loss can be prevented.

  As described above, the intake air temperature increase control shown in FIG. 4 and the intake air temperature decrease control shown in FIG. 6 are executed according to the temperature of the catalyst 80. That is, when the temperature of the catalyst 80 exceeds the allowable temperature, the intake air temperature increase control is not executed, and the intake air temperature decrease control is executed (step S4). Thus, the ECU 90 determines whether or not the intake air temperature increase control can be executed according to the temperature of the catalyst 80. Thereby, the melting loss of the catalyst 80 can be prevented.

Next, a modified example of the intake air temperature rise control executed by the ECU 90 will be described.
FIG. 7 is a map for the ECU 90 to execute a modification of the intake air temperature rise control. This map is stored in advance in the ROM. In this map, the vertical axis indicates the temperature of the catalyst 80 immediately before the fuel cut, and the horizontal axis indicates the intake air temperature immediately before the fuel cut. As shown in FIG. 7A, when the temperature of the catalyst 80 immediately before the fuel cut and the intake air temperature immediately before the fuel cut are both high, the intake air temperature decrease control is executed. On the other hand, when the temperature of the catalyst 80 immediately before the fuel cut and the intake air temperature immediately before the fuel cut are both low, the intake air temperature rise control is executed.

  Further, as shown in FIG. 7B, in the region where the intake air temperature rise control is executed, the inside air introduction region A where the inside air is introduced into the engine 60 from the highest temperature of the catalyst 80, and the fuel in the exhaust stroke. Is divided into an exhaust stroke injection region B where the fuel is injected and a purge region C where the evaporated fuel is purged into the intake system. The ECU 90 executes control corresponding to each region based on this map. Specifically, it is executed as follows.

  FIG. 8 is a flowchart showing a modified example of the intake air temperature rise control executed by the ECU 90. As shown in FIG. 8, the ECU 90 determines whether or not the intake air temperature is equal to or lower than the outside air temperature (step S31a). If the determination is negative, this process ends. In the case of an affirmative determination, the ECU 90 determines whether or not it is included in the inside air introduction region A shown in FIG. 7B based on the outputs from the intake air temperature sensor 71 and the catalyst temperature sensor 73 (step S32a). ). If the determination is affirmative, the ECU 90 controls the operation of the switching valve 15 so that the inside air is introduced into the engine 60 (step S33a). In the case of negative determination, the ECU 90 determines whether or not it is included in the exhaust stroke injection region B based on the outputs from the intake air temperature sensor 71 and the catalyst temperature sensor 73 (step S34a). If the determination is affirmative, the ECU 90 executes an exhaust stroke injection process in which fuel is injected from the injector 63 in the exhaust stroke of the engine 60 (step S35a). Thus, by injecting fuel in the exhaust stroke when the fuel is cut, the mixture of fuel and intake air reaches the catalyst 80 without being combusted, and the fuel is combusted depending on the temperature of the catalyst 80. With the above operation, the temperature of the catalyst 80 can be raised.

  If the determination is negative, the ECU 90 opens a purge valve 35 to execute a purge process for purging the evaporated fuel to the intake system (step S36a). By performing the purge process when the fuel is cut, the evaporated fuel reaches the catalyst 80 and the fuel is combusted depending on the temperature of the catalyst 80. The temperature of the catalyst 80 can also be raised by the above action.

  Here, the temperature increase reactivity of the catalyst 80 when the exhaust stroke injection process is executed and when the purge process is executed will be described. FIG. 9 is an explanatory diagram of the temperature rising reactivity of the catalyst 80. FIGS. 9A and 9B are graphs showing the temperature rise reactivity of the catalyst 80 when the exhaust stroke injection process and the purge process are executed, respectively. As shown in FIGS. 9A and 9B, the temperature rising reactivity of the catalyst 80 is faster in the purge process than in the exhaust stroke injection process. The reason for this is that in the exhaust stroke injection process, the amount of heat is lost due to the atomization of the fuel, so the temperature rising reaction of the catalyst 80 is somewhat dull, but in the purge process, the purged fuel has already evaporated. Therefore, the amount of heat is not lost due to evaporation.

  In the map shown in FIG. 7B, each region is set in consideration of the temperature-rising reactivity of the catalyst 80 as described above. That is, when the temperature of the catalyst 80 is relatively high and the exhaust stroke injection process or the purge process is executed, the catalyst 80 may be heated more than expected and may be melted even when the fuel is cut. is there. For this reason, when the temperature of the catalyst 80 is relatively high, the risk of the catalyst 80 being melted is prevented by introducing the inside air.

  Further, when the temperature of the catalyst 80 is relatively medium, it is not sufficient to suppress the temperature drop of the catalyst 80 by the inside air introduction process, and therefore, the temperature increase of the catalyst 80 is performed by executing the exhaust stroke injection process. I am trying. Further, even when the temperature of the catalyst 80 is relatively low, it is not sufficient to suppress the temperature drop of the catalyst 80 by the inside air introduction process, so that the temperature of the catalyst 80 is raised quickly by executing the purge process. be able to.

  In addition, the ECU 90 alternatively executes each process according to the temperature of the catalyst 80 in consideration of the temperature rise reactivity of the catalyst 80 in the exhaust stroke injection process and the purge process. As described above, since the temperature rise reactivity of the catalyst 80 is sharper in the purge process than in the exhaust stroke injection process, if the exhaust stroke injection process is executed when the temperature of the catalyst 80 is low, the catalyst 80 is removed earlier. This is because if the temperature cannot be raised and the temperature of the catalyst 80 is medium, if the purge process is executed, the catalyst 80 may be melted.

  FIG. 10 is a configuration diagram of an engine system according to the second embodiment. In the engine system according to the second embodiment shown in FIG. 10, a bypass passage 18 that bypasses the compressor 41 is provided in the first intake passage 10a. The bypass passage 18 is provided with an open / close valve 19. The on-off valve 19 opens and closes the bypass passage 18 based on a command from the ECU 90. When the bypass passage 18 is blocked by the on-off valve 19, the intake air introduced from the first intake passage 10 a is compressed by the compressor 41 and introduced into the engine 60.

  On the other hand, when the bypass passage 18 is communicated by the on-off valve 19, the intake air introduced from the first intake passage 10a is compressed by the compressor 41. A part of the compressed intake air is compressed by the bypass passage. 18 is again returned to the first intake passage 10a upstream of the compressor 41. This is because the pressure on the downstream side of the compressor 41 is higher than that on the upstream side of the compressor 41. The on-off valve 19 corresponds to an opening / closing means.

  11 illustrates an intake air temperature rise control executed by the ECU 90a employed in the engine system according to the second embodiment. FIG. 11 illustrates an example of the intake air temperature rise control performed by the ECU 90a employed in the engine system according to the second embodiment. It is a flowchart. After executing the process of step S32b, the ECU 90a determines again whether the intake air temperature is lower than the outside air temperature (step S33b). In the case of a negative determination, the ECU 90a ends this process. If the determination is affirmative, the ECU 90a controls the open / close valve 19 to open (step S34b). As a result, the state where the bypass passage 18 communicates is continued. By continuing this state, a part of the intake air compressed by the compressor 41 flows again to the upstream side of the compressor 41 and is compressed again. When the intake air is compressed in this way, the intake air temperature increases as the intake air pressure increases. As described above, the temperature of the intake air can be increased.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

  In the engine system according to the second embodiment, the ECU 90a performs a process of returning a part of the intake air compressed by the compressor 41, an exhaust stroke injection process, and a purge process according to the temperature of the catalyst 80 immediately before the fuel cut. It may be configured to execute alternatively.

1 is a configuration diagram of an engine system according to Embodiment 1. FIG. It is the graph which showed the relationship between the temperature of a catalyst, internal temperature, and external temperature. It is the flowchart figure which showed an example of the process which ECU performs. It is the flowchart which showed an example of the intake air temperature rise control which ECU performs. 6 is a graph comparing the temperature of the catalyst and the temperature of the intake air when the intake air temperature rise control is executed and when it is not executed. It is the flowchart which showed an example of the intake air temperature fall control which ECU performs. It is a map in order that ECU may perform the modification of intake air temperature rise control. 6 is a flowchart showing a modification of intake air temperature rise control executed by the ECU. It is explanatory drawing of the temperature rising reactivity of a catalyst. FIG. 3 is a configuration diagram of an engine system according to a second embodiment. 6 is a flowchart illustrating an example of intake air temperature rise control executed by an ECU employed in an engine system according to a second embodiment.

Explanation of symbols

10a 1st intake passage 10b 2nd intake passage 12 Intercooler 13 Surge tank 15 Switching valve (switching means)
18 Bypass passage 19 On-off valve (open / close means)
20 exhaust passage 30 fuel tank 40 supercharger 41 compressor 60 engine 71 intake air temperature sensor 72 outside air temperature sensor 73 catalyst temperature sensor 80 catalyst 90 ECU (fuel cut means, catalyst temperature drop control means)

Claims (6)

In a control device for an internal combustion engine comprising a catalyst for purifying exhaust gas of the internal combustion engine, and a fuel cut means for cutting the supply of fuel to the internal combustion engine when a predetermined condition is satisfied,
A first intake passage that guides outside air outside the engine room in which the internal combustion engine is housed to the internal combustion engine as intake air;
A second intake passage for guiding the internal air in the engine room as intake air to the internal combustion engine;
Switching means for selectively switching the communication between the first and second intake passages;
A control device for an internal combustion engine, comprising: a catalyst temperature lowering control means for executing an intake air temperature raising process for controlling the switching means so as to bring the second intake passage into a communication state at the time of fuel cut. In a control device for an internal combustion engine, comprising: a catalyst for purifying exhaust gas of the internal combustion engine; and fuel injection control means for cutting off the supply of fuel to the internal combustion engine when a predetermined condition is satisfied,
A bypass passage that bypasses a supercharger that supercharges intake air; and an opening and closing means that opens and closes the bypass passage;
And a catalyst temperature drop control means for performing an intake air temperature raising process for controlling the opening and closing means so that a part of the intake air supercharged by the supercharger at the time of fuel cut is returned to the supercharger again. A control device for an internal combustion engine. Comprising catalyst temperature acquisition means for acquiring the temperature of the catalyst;
3. The control device for an internal combustion engine according to claim 1, wherein the catalyst temperature lowering control unit determines whether or not to execute the intake air temperature raising process according to the acquired temperature of the catalyst. An intake air temperature acquisition means for acquiring the intake air temperature;
The control apparatus for an internal combustion engine according to claim 1 or 2, wherein the catalyst temperature decrease control means determines whether or not to execute the intake air temperature increase process according to the acquired intake air temperature.   The catalyst temperature lowering control means can execute an exhaust stroke injection process in which fuel injection is performed in an exhaust stroke at the time of fuel cut, and the intake air temperature increase process when the obtained catalyst temperature is relatively high The control apparatus for an internal combustion engine according to any one of claims 1 to 4, wherein the exhaust stroke injection processing is alternatively executed when the engine speed is relatively low. The catalyst temperature drop control means can execute a purge process for purging the evaporated fuel in the fuel tank to the intake system when the fuel is cut, and if the acquired catalyst temperature is relatively high, the intake temperature The control device for an internal combustion engine according to any one of claims 1 to 4, wherein when the temperature raising process is relatively low, the purge process is executed alternatively.

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