JP2009127513A - Control device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device of an internal combustion engine preventing variation of an EGR gas amount with control of an exhaust gas regulating valve and stabilizing a combustion condition. <P>SOLUTION: The control device of the internal combustion engine comprises a heat exchanger, an exhaust switching valve and a valve control means. The heat exchanger has the functions of recovering heat from exhaust gas and cooling EGR gas as an EGR cooler function. The exhaust switching valve regulates an exhaust gas amount from an exhaust passage to the heat exchanger. The valve control means closes an EGR valve and stops circulation of EGR gas when the EGR valve is in an open state before operation of the exhaust switching valve. With this, variation of back pressure by operation of the exhaust switching valve can be prevented. The EGR gas amount can be prevented from varying and the combustion condition can be prevented from becoming unstable. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  2. Description of the Related Art Conventionally, in an internal combustion engine equipped with an exhaust gas recirculation (EGR) device that recirculates a part of exhaust gas to an intake system, a heat exchanger for recovering thermal energy from the exhaust gas is arranged. The control for passing the exhaust gas to the heat exchanger is performed by opening and closing an exhaust gas regulating valve provided on the exhaust passage.

  In Patent Document 1, when the catalyst temperature is low, the exhaust gas regulating valve is set to the fully open position to minimize the amount of exhaust gas flowing through the connecting pipe, and as the catalyst temperature rises, the position of the exhaust gas regulating valve is set to the intermediate position An exhaust gas circulation device for an engine that increases the amount of exhaust gas flowing through a connecting pipe as a fully closed position is described.

JP 2001-280200 A

  Generally, when the amount of gas (EGR gas) to be recirculated by the EGR device is increased with respect to the intake air amount, the air in the combustion chamber of the internal combustion engine tends to decrease and combustion tends to become unstable. For this reason, the recirculation of the EGR gas is performed in a state of a predetermined engine water temperature or higher. However, if the exhaust gas regulating valve is operated during the recirculation process of EGR gas, the amount of EGR gas fluctuates due to fluctuations in the back pressure, and as a result, the combustion state may become unstable. Patent Document 1 does not discuss the above-described problem.

  The present invention has been made to solve the above-described problems, and provides a control device for an internal combustion engine that prevents fluctuations in the amount of EGR gas accompanying control of an exhaust gas regulating valve and stabilizes the combustion state. For the purpose.

  In one aspect of the present invention, an internal combustion engine control device having an EGR device adjusts a heat exchanger having both an exhaust heat recovery function and an EGR cooler function, and a flow of exhaust gas from an exhaust passage to the heat exchanger. An exhaust gas switching valve and valve control means for closing the EGR valve when the exhaust gas switching valve is operated are provided.

  The control device for an internal combustion engine is a control device for an internal combustion engine having an EGR device that recirculates a part of exhaust gas to an intake system. The control device for an internal combustion engine includes a heat exchanger, an exhaust gas switching valve, and valve control means. The heat exchanger collects heat from the exhaust gas and has a function of cooling the EGR gas as an EGR cooler function. The exhaust switching valve adjusts the amount of exhaust gas from the exhaust passage to the heat exchanger. The valve control means is, for example, an ECU (Electronic Control Unit), and closes the EGR valve and stops the recirculation of the EGR gas when the EGR valve is open before the operation of the exhaust gas switching valve. By doing in this way, the fluctuation | variation of the back pressure by operation of the exhaust gas switching valve can be prevented. Therefore, it is possible to prevent the amount of EGR gas from fluctuating and to prevent the combustion state from becoming unstable.

  In one aspect of the control apparatus for an internal combustion engine, the valve control means opens the EGR valve again after the operation of the exhaust gas switching valve is completed when the EGR valve is switched from the closed state to the open state. It is characterized by that.

  In this aspect, the EGR valve is closed only during the operation of the exhaust gas switching valve, and the EGR valve is returned to the original state after the operation of the exhaust gas switching valve is completed. Therefore, it is possible to minimize the suspension time of the exhaust gas recirculation by the EGR device and to prevent the combustion state from becoming unstable.

  In another aspect of the control apparatus for an internal combustion engine, the valve control means is executed when the exhaust gas switching valve is operated from an open state to a closed state.

  In another aspect of the control device for an internal combustion engine, the exhaust gas passes from the exhaust passage to the heat exchanger, and the exhaust gas passes from the heat exchanger to the exhaust passage. And a second bypass passage for adjusting the flow of the exhaust gas by opening and closing the second bypass passage and the exhaust passage.

  In this way, when the exhaust switching valve closes the second bypass passage, the heat recovery of the exhaust gas by the heat exchanger can be performed, and when the exhaust passage is closed, the heat recovery is Without this, warming up of the catalyst downstream of the exhaust passage can be performed.

  Another aspect of the control device for an internal combustion engine described above further includes a first catalyst and a second catalyst, and the first catalyst is located upstream of the first bypass passage in the exhaust passage, The second catalyst is located downstream of the second bypass passage in the exhaust passage. The first catalyst is mainly a small catalyst having a small volume, and the second catalyst is a large catalyst having a larger volume than the first catalyst. In this aspect, since the first catalyst is always warmed up by the exhaust gas, the exhaust gas can be purified by the first catalyst even when the second catalyst has not reached the activation temperature. As a result, emission deterioration can be further suppressed.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

[Control device for internal combustion engine]
First, the configuration of the control device for an internal combustion engine according to the present embodiment will be described. FIG. 1 is a block diagram showing an example of a schematic configuration of a control device 100 for an internal combustion engine having an engine 3 according to the present embodiment. In FIG. 1, solid arrows indicate the flow of intake and exhaust, and broken arrows indicate control signals. The control device 100 for an internal combustion engine is mounted on a vehicle and uses the output of the engine 3 as a driving power source. The control device 100 for the internal combustion engine includes the engine 3, the EGR device 5, the catalysts 30a and 30b, the exhaust gas switching valve 20, various sensors 25 and 26, and the ECU 10 as components.

  The engine 3 is supplied with air (intake air) through the intake passage 2. A throttle valve 22 that adjusts the amount of inflow into the engine is disposed in the intake passage 2. Further, an exhaust passage 4 is connected to the engine 3, and exhaust gas generated by the above-described combustion is discharged from the exhaust passage 4.

  The control device 100 for an internal combustion engine includes an EGR device 5 that recirculates a part of the exhaust gas to the intake system. The EGR device 5 includes an EGR passage 6, a heat exchanger 7, and an EGR valve 9. The EGR passage 6 has one end connected to the exhaust passage 4 and the other end connected to the intake passage 2.

  The heat exchanger 7 functions as an EGR cooler that cools the exhaust gas that passes through the EGR passage 6 and also functions as an exhaust heat recovery device that transmits thermal energy contained in the exhaust gas to the engine coolant. That is, the heat exchanger 7 is a heat exchanger in which the functions of the EGR cooler and the exhaust heat recovery device are integrated. Specifically, the heat exchanger 7 is configured as a water-cooled type, and performs cooling using cooling water passing through the inside. That is, the heat exchanger 7 cools the exhaust gas by exchanging heat between the cooling water and the exhaust gas. The cooling water passes through the cooling water passage 8 and is circulated by a water pump (not shown).

  The EGR valve 9 is a valve for controlling the amount of exhaust gas to be recirculated (hereinafter referred to as “EGR amount”). The opening degree of the EGR valve 9 is controlled by a control signal S2 supplied from the ECU 10.

  A first catalyst 30 a and a second catalyst 30 b are disposed in the exhaust passage 4. The first catalyst 30 a is a small catalyst having a small volume, and is a catalyst disposed in the exhaust passage 4 downstream of the engine 3 and upstream of the first bypass passage 15. In a preferred example, the first catalyst 30a is preferably a NOx storage reduction catalyst that stores and purifies NOx.

  The second catalyst 30b is a large-sized catalyst having a larger volume than the first catalyst 30a, and is a catalyst disposed downstream of the exhaust gas switching valve 20 in the exhaust passage 4. The second catalyst 30b is preferably a NOx storage reduction catalyst that stores and purifies NOx, similarly to the first catalyst 30a.

  The first bypass passage 15 is a passage for connecting the exhaust passage 4 and the heat exchanger 7 and flowing the exhaust gas from the exhaust passage 4 to the heat exchanger 7. The second bypass passage 16 is a passage for connecting the exhaust passage 4 and the heat exchanger 7 and allowing the exhaust gas to flow from the heat exchanger 7 to the exhaust passage 4.

  The exhaust gas switching valve 20 is a valve that adjusts the flow of exhaust gas by opening and closing the second bypass passage 16 and the exhaust passage 4. The exhaust switching valve 20 is controlled to be opened and closed by a control signal S1 supplied from the ECU 10.

  Further, the control device 100 for the internal combustion engine is provided with various sensors. Specifically, an engine water temperature sensor 25 that measures the water temperature is provided on the cooling water passage 8 in the head portion of the engine 3. The second catalyst 30b is provided with a catalyst bed temperature sensor 26 for measuring the temperature of the second catalyst 30b (hereinafter referred to as “catalyst bed temperature”). The engine water temperature sensor 25 and the catalyst bed temperature sensor 26 supply detection signals S5 and S6 corresponding to the detected temperatures to the ECU 10, respectively. The ECU 10 controls the EGR valve 9 and the exhaust gas switching valve 20 based on the engine water temperature and the catalyst bed temperature.

  The ECU 10 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like (not shown). The ECU 10 controls the engine 3 based on detection signals supplied from various sensors. For example, the ECU 10 determines the required torque of the engine 3 based on a detection signal supplied from an accelerator opening sensor (not shown). Then, the ECU 10 controls the engine 3 based on the determined required torque.

  The ECU 10 controls the exhaust gas switching valve 20 and the EGR valve 9 by transmitting control signals S1 and S2 to them. Therefore, the ECU 10 functions as valve control means in the present invention.

  The configuration of the control device 100 for an internal combustion engine to which the present invention is applicable is not limited to this. For example, the heat exchanger 7 may be disposed downstream of the second catalyst 30b in the exhaust passage 4. In this case, since the exhaust gas always passes through the second catalyst 30b before passing through the heat exchanger 7, the warm-up of the second catalyst 30b is performed regardless of whether or not the exhaust gas passes through the heat exchanger 7. Can be executed.

  Next, the state of the airflow of each exhaust gas, which changes by the control of the EGR valve 9 and the exhaust gas switching valve 20 performed by the ECU 10, will be described.

  FIG. 2A shows a state in which the ECU 10 controls the EGR valve 9 and the exhaust gas switching valve 20 so that the EGR valve 9 is closed and the exhaust gas switching valve 20 closes the second bypass passage 16. That is, the state 70 is a state when the ECU 10 controls the EGR valve 9 and the exhaust gas switching valve 20 so that the exhaust gas is not recirculated by the EGR device 5 and the exhaust gas switching valve 20 is positioned on the broken line 20a. Hereinafter, the state 70 is referred to as “catalyst warm-up mode”. An arrow 80 indicates the flow of exhaust. Hereinafter, controlling the exhaust gas switching valve 20 to be positioned on the broken line 20a is simply expressed as “closing the exhaust gas switching valve 20” or “making the exhaust gas switching valve 20 closed”.

  In the catalyst warm-up mode, the exhaust gas discharged from the engine 3 does not pass through the heat exchanger 7, so that the heat of the exhaust gas is not recovered by the heat exchanger 7. Therefore, the exhaust gas follows the flow of the arrow 80 and passes through the second catalyst 30b. Thereby, the second catalyst 30b is warmed up by the exhaust gas.

  FIG. 2B shows a state in which the ECU 10 controls the EGR valve 9 and the exhaust gas switching valve 20 so as to close the EGR valve 9 and open the exhaust gas switching valve 20. Hereinafter, the state 71 is referred to as a “heat recovery mode”. An arrow 81 indicates the flow of exhaust. Hereinafter, controlling the exhaust gas switching valve 20 to be positioned on the broken line 20b is expressed as “opening the exhaust gas switching valve 20” or “opening the exhaust gas switching valve 20”.

  In the heat recovery mode, as indicated by an arrow 81, the exhaust gas discharged from the engine 3 passes through the heat exchanger 7, whereby the heat of the exhaust gas is recovered by the heat exchanger 7.

  FIG. 3A shows a state in which the ECU 10 controls the EGR valve 9 and the exhaust gas switching valve 20 so that the EGR valve 9 is opened and the exhaust gas switching valve 20 is closed. Hereinafter, the state 72 is referred to as “EGR cooler mode”. Arrows 82a and 82b indicate the flow of exhaust.

  In the EGR cooler mode, as indicated by the arrow 82a, part of the exhaust gas discharged from the engine 3 is recirculated to the intake passage 2 by the EGR device 5 again. Thereby, the negative pressure of the intake passage 2 is relatively lowered, and the fuel consumption can be improved by the reduction of the pumping loss. Further, the exhaust gas that is not recirculated by the EGR device 5 passes through the second catalyst 30b without passing through the heat recovery unit 7, as indicated by the arrow 82b. As a result, the second catalyst 30b is warmed up by the exhaust gas.

  FIG. 3B shows a state in which the ECU 10 controls the EGR valve 9 and the exhaust gas switching valve 20 so that the EGR valve 9 is opened and the exhaust gas switching valve 20 is opened. Hereinafter, the state 73 is referred to as “heat recovery / EGR cooler mode”. Arrows 83a and 83b indicate the flow of exhaust.

  In the heat recovery / EGR cooler mode, as indicated by an arrow 83a, a part of the exhaust gas discharged from the engine 3 is returned to the intake passage 2 again by the EGR device 5. Thereby, the negative pressure of the intake passage 2 is relatively lowered, and the fuel consumption can be improved by the reduction of the pumping loss. In the heat recovery / EGR cooler mode, as indicated by arrows 83a and 83b, the exhaust gas discharged from the engine 3 passes through the heat exchanger 7 so that the heat of the exhaust gas is recovered by the heat exchanger 7. Is done.

  Next, a mode switching method according to temperature changes of the engine water temperature and the catalyst bed temperature will be specifically described. In FIG. 4, an example of a graph showing the relationship between the elapsed time from the start of the engine 3 and the engine water temperature is shown in the upper part, and the relationship between the elapsed time from the start of the engine 3 and the catalyst bed temperature of the second catalyst 30b. An example of a graph showing is shown below.

  In FIG. 4, the second catalyst 30b reaches a predetermined activation temperature T3 (herein referred to as “first catalyst bed temperature”) from time t0 to time t1, which is the time of starting, that is, in period A. Absent. Therefore, the ECU 10 needs to close the exhaust gas switching valve 20 in order to pass the exhaust gas to the second catalyst 30b without recovering the heat of the exhaust gas with the heat exchanger 7.

  The ratio of the EGR amount to the total amount of fresh air and EGR amount supplied from the throttle valve 22 (hereinafter referred to as “EGR rate”) increases as the value increases. The temperature tends to decrease and combustion becomes unstable. Therefore, the EGR device 5 starts to recirculate the EGR gas when the engine coolant temperature is equal to or higher than a predetermined engine coolant temperature T1 (hereinafter referred to as “first engine coolant temperature”). Therefore, during the period A in FIG. 4, the engine water temperature is equal to or lower than the first engine water temperature T1, so the ECU 10 needs to close the EGR valve 9.

  As described above, in the period A, the ECU 10 executes the catalyst warm-up mode shown in FIG.

  Next, at time t1, the catalyst bed temperature reaches the first catalyst bed temperature T3, and the warm-up is completed. Therefore, as shown in FIG. 2B, the ECU 10 performs control to open the exhaust gas switching valve 20 in the period B. That is, the ECU 10 executes the heat recovery mode in the period B. In the period B, as in the period A, since the engine water temperature has not reached the first engine water temperature T1, the EGR gas is not recirculated.

  Next, at time t2, the warm-up of the second catalyst 30b is completed, and the engine water temperature has reached or exceeded the first engine water temperature T1. In this case, the ECU 10 opens the EGR valve 9 at time t2 and starts recirculation of EGR gas. That is, in the period C, the ECU 10 executes the heat recovery / EGR cooler mode.

  Next, in a period after time t3, that is, in period D, the engine water temperature reaches a predetermined temperature T2 higher than the first engine water temperature (hereinafter referred to as “second engine water temperature”). When the engine water temperature reaches the second engine water temperature T2, it is necessary to cool only the engine 3 and prevent heat recovery from the exhaust gas in order to prevent boiling of the cooling water. Therefore, in the period D, the ECU 10 switches the exhaust gas switching valve 20 to the closed state. That is, the ECU 10 executes the EGR cooler mode in the period D.

  When the ECU 10 executes the above exhaust gas state control, heat recovery from the exhaust gas and adjustment of the catalyst bed temperature can be performed. However, at time t3, that is, when the exhaust state is switched from the heat recovery / EGR cooler mode to the EGR cooler mode, the back pressure fluctuates and the EGR amount fluctuates. And the combustion state of the engine 3 may become unstable due to the change in the EGR amount.

  This will be described in detail. In order to execute the above-described state control, the ECU 10 holds in advance a suitable value of the opening amount of the EGR valve 9 according to the operating state of the engine 3 as a map. The amount of EGR varies depending on the pressure difference between the back pressure and the intake pressure. In the heat recovery / EGR cooler mode, the back pressure at the mouth of the EGR passage 6 on the heat recovery device 7 side is high, and the back pressure in the EGR mode is low. Therefore, the ECU 10 has the above-described map for each of the open state and the closed state of the exhaust gas switching valve 20.

  However, during the operation of the exhaust gas switching valve 20, that is, during the state transition between the open state and the closed state, neither of the above two maps can be applied, and as a result, the EGR amount changes. The combustion state of the engine 3 may become unstable.

  Therefore, in the present embodiment, the EGR valve 9 is temporarily closed during operation of the exhaust gas switching valve 20 to prevent the EGR amount from changing. That is, the heat recovery mode and the catalyst warm-up mode are bypassed before switching from the heat recovery / EGR cooler mode to the EGR cooler mode. Thereby, since the EGR gas is not recirculated during the operation of the exhaust gas switching valve 20, it is possible to prevent the combustion state of the engine 3 from becoming unstable due to the change in the EGR amount.

  FIG. 5 is a flowchart illustrating an example of processing of the control method of the EGR valve 9 and the exhaust gas switching valve 20 for preventing the above-described change in the EGR amount performed by the ECU 10. Note that the flowchart shown in FIG. 5 is executed by the ECU 10 before the operation of the exhaust gas switching valve 20.

  First, the ECU 10 determines whether the exhaust state is the heat recovery / EGR cooler mode (step S101, step S102). Specifically, first, it is determined whether or not the exhaust gas switching valve 20 is in the position of the broken line 20b, that is, whether or not it is in an open state (step S101).

  When the ECU 10 determines that the exhaust gas switching valve 20 is not at the position of the broken line 20b but at the position of the broken line 20a (step S101; No), the ECU 10 ends the processing of the flowchart and executes the operation of the exhaust gas switching valve 20. To do.

  On the other hand, when the ECU 10 determines that the exhaust gas switching valve 20 is at the position of the broken line 20b, that is, in the open state (step S101; Yes), the ECU 10 determines whether the EGR valve 9 is open, that is, whether EGR is being executed. (Step S102).

  If the ECU 10 determines that the EGR valve 9 is closed (step S102; No), the ECU 10 ends the process of the flowchart and executes the operation of the exhaust gas switching valve 20.

  On the other hand, when the ECU 10 determines that the EGR valve 9 is in the open state (step S102; Yes), the ECU 10 transmits a signal S2 to close the EGR valve 9 (step S103). Then, it is determined whether or not the EGR valve 9 has changed to the closed state (step S104), and if the EGR valve 9 is not in the closed state (step S104; No), the ECU 10 signals that the EGR valve 9 be closed again. S2 is transmitted (step S103).

  After confirming that the EGR valve 9 is closed (step S104; Yes), the ECU 10 switches the exhaust gas switching valve 20. That is, the signal S1 is transmitted so as to close the exhaust gas switching valve 20 (step S105). In this case, since the EGR is in a stopped state, the back pressure does not fluctuate even by the control of the exhaust gas switching valve 20 described above, and the problem of fluctuation of the EGR amount does not occur. Therefore, instability of the combustion state due to operation of the exhaust gas switching valve 20 can be prevented.

  Then, the ECU 10 confirms whether or not the exhaust gas switching valve 20 has been closed, i.e., moved to the position of the broken line 20a. If the exhaust gas switching valve 20 is not in the closed state (step S106; No), the ECU 10 executes step S105 again.

  Next, after confirming that the exhaust gas switching valve 20 is in the closed state (step S106; Yes), the ECU 10 opens the EGR valve 9 temporarily closed for controlling the exhaust gas switching valve 20 to the open state again. (Step S107). By the above processing, the exhaust state can be switched from the heat recovery / EGR cooler mode to the EGR cooler mode while preventing an unexpected change in the EGR amount.

  In the flowchart shown in FIG. 5, the ECU 10 performs control to temporarily close the EGR valve 9 when the exhaust state is changed from the heat recovery / EGR cooler mode to the EGR mode. However, actually, there is a case where the EGR cooler mode is changed to the heat recovery / EGR cooler mode. Even in this case, since the exhaust gas switching valve 20 is controlled during the control of the EGR, an unexpected change in the EGR amount may occur during the operation of the exhaust gas switching valve 20.

  FIG. 6 shows an example of a flowchart considering the above-described case. The flowchart shown in FIG. 6 is executed by the ECU 10 before the operation of the exhaust gas switching valve 20 as in the flowchart of FIG.

  First, the ECU 10 determines whether or not the EGR valve 9 is in an open state (step S201). If the EGR valve 9 is in the open state (step S201; Yes), the ECU 10 determines that the exhaust state is the EGR cooler mode or the heat recovery / EGR cooler mode, and closes the EGR valve 9 (Step S202, Step S203).

  Next, after confirming that the EGR valve 9 is in the closed state (step S203; Yes), the ECU 10 performs switching of the exhaust gas switching valve 20 (step S204, step S205). In this case, the switching operation of the exhaust gas switching valve 20 is different from the process of the flowchart of FIG. 5 in two ways: a switching operation for switching from the open state to the closed state and a switching operation for switching from the closed state to the open state.

  Then, after confirming that the switching operation of the exhaust gas switching valve 20 has been completed (step S205; Yes), the temporarily closed EGR valve 9 is opened again (step S206), and the processing of the flowchart ends.

  With the above processing, not only when the heat recovery / EGR cooler mode is changed to the EGR mode but also when the EGR cooler mode is changed to the heat recovery / EGR cooler mode, the combustion state of the engine 3 due to the switching of the exhaust gas switching valve 20 is changed. Instability can be prevented.

It is a figure which shows schematic structure of the control apparatus of an internal combustion engine. It is a figure which shows the flow of exhaust in the state which closed the EGR valve. It is a figure which shows the flow of exhaust in the state which opened the EGR valve. It is a figure which shows an example of the graph of the engine water temperature and catalyst bed temperature with time progress after a driving | running | working start. It is a flowchart which shows an example of the control processing which ECU performs at the time of operation of an exhaust gas switching valve. It is a flowchart which shows another example of the control processing which ECU performs at the time of operation of an exhaust gas switching valve.

Explanation of symbols

3 Engine 7 Heat exchanger 9 EGR valve 10 ECU
30a First catalyst 30b Second catalyst 100 Control device for internal combustion engine

Claims (5)

In a control device for an internal combustion engine having an EGR device,
A heat exchanger having both an exhaust heat recovery function and an EGR cooler function;
An exhaust gas switching valve for adjusting the flow of exhaust gas from an exhaust passage to the heat exchanger;
And a valve control means for closing the EGR valve when operating the exhaust gas switching valve.   2. The control device for an internal combustion engine according to claim 1, wherein, when the EGR valve is switched from a closed state to an open state, the valve control means opens the EGR valve again after the operation of the exhaust gas switching valve is completed.   The control apparatus for an internal combustion engine according to claim 1 or 2, wherein the valve control means is executed when the exhaust gas switching valve is operated from an open state to a closed state. A first bypass passage for exhaust gas to pass from the exhaust passage to the heat exchanger;
A second bypass passage for exhaust gas to pass from the heat exchanger to the exhaust passage,
The control device for an internal combustion engine according to any one of claims 1 to 3, wherein the exhaust gas switching valve adjusts the flow of exhaust gas by opening and closing the second bypass passage and the exhaust passage. Further comprising a first catalyst and a second catalyst;
The first catalyst is located upstream of the first bypass passage in the exhaust passage;
The control device for an internal combustion engine according to any one of claims 1 to 4, wherein the second catalyst is located downstream of the second bypass passage in the exhaust passage.

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