Engine control device and engine control method

Abstract

The present invention provides an engine control device and an engine control method. The engine control device includes a processing circuit, the processing circuit being configured to perform catalyst early activation control by performing a first process of maintaining the opening of a wastegate valve at a predetermined first opening, and performing a second process of setting the opening of the wastegate valve to an opening different from the first opening after performing the first process.

Description

Technical Field

[0001] The present disclosure relates to an engine control device for controlling an engine equipped with a turbocharger. In addition, the present disclosure relates to an engine control method. Background Art

[0002] In a turbocharger, there is a turbocharger having a bypass passage that bypasses the turbine and allows exhaust gas to flow, and an exhaust bypass valve that opens and closes the bypass passage. In addition, Japanese Patent Gazette No. 2018-145914 describes an engine control device that controls an engine including a turbocharger having a bypass passage and an exhaust bypass valve. In the engine control device described in the document, when the engine is cold-started, a catalyst early activation control is performed to advance the activation period of the catalyst device by opening the exhaust bypass valve. When the exhaust bypass valve is opened, the exhaust gas is blown to a part of the catalyst device. Therefore, compared with the case where the exhaust gas is evenly blown to the entire catalyst device, the period of forming the "part where the catalyst is activated" is advanced. Therefore, by performing the catalyst early activation control, the period when the catalyst device starts exhaust purification can be advanced.

[0003] When the catalyst early activation control is completed, only a portion of the catalyst device is in an activated state. Therefore, if the accelerator pedal is depressed immediately after the catalyst early activation control is completed and a large amount of exhaust gas flows into the catalyst device, most of the exhaust gas may be discharged to the outside air in an unpurified state. Summary of the invention

[0004] According to one embodiment of the present disclosure, an engine control device is provided, which is applied to an engine, the engine comprising: a turbine, which is arranged in an exhaust passage; a bypass passage, which branches from the exhaust passage at a position in the exhaust passage on the upstream side of the turbine, and merges with the exhaust passage at a position in the exhaust passage on the downstream side of the turbine; a wastegate valve, which is arranged at a merging position in the bypass passage where the wastegate merges with the exhaust passage; and a catalyst device for exhaust purification, which is arranged at a portion in the exhaust passage on the downstream side of the merging position, wherein the engine control device is configured to perform catalyst early activation control for promoting activation of the catalyst device by maintaining the wastegate valve in an open state when the engine is cold started. The engine control device includes a processing circuit, which is configured to perform the catalyst early activation control by performing a first process for maintaining the opening of the wastegate valve at a predetermined first opening, and performing a second process for making the opening of the wastegate valve different from the first opening after performing the first process.

[0005] According to one embodiment of the present disclosure, an engine control method is provided, the engine control method being a control method for an engine having an exhaust bypass valve and a catalyst device for exhaust purification, the exhaust bypass valve being configured to open a bypass passage that bypasses a turbine disposed in an exhaust passage, the catalyst device being disposed in a portion of the exhaust passage that is downstream of the exhaust bypass valve. The engine control method comprises: performing a first process of injecting exhaust gas into a first region of the catalyst device by maintaining the opening of the exhaust bypass valve at a predetermined first opening when the engine is cold started; and performing a second process of injecting exhaust gas into a second region of the catalyst device that is different from the first region by maintaining the opening of the exhaust bypass valve at a second opening that is different from the first opening after performing the first process. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 It is a diagram schematically showing the configuration of the engine control device according to the first embodiment.

[0007] Figure 2 1 is a flowchart showing a process procedure of catalyst early activation control executed by the engine control device.

[0008] Figure 3 It is a diagram showing the state of the periphery of the catalyst device during the implementation of the first process in the catalyst early activation control.

[0009] Figure 4 This is a diagram showing the state of the catalyst device periphery immediately after the control is completed, with respect to a comparative example in which the catalyst early activation control is completed only by the first process.

[0010] Figure 5 It is a diagram showing the state of the periphery of the catalyst device during the implementation of the second process in the catalyst early activation control.

[0011] Figure 6 It is a time chart related to the catalyst early activation control in the engine control device of the second embodiment, (A) shows the transition of the WGV opening degree, and (B) shows the transition of the ignition timing.

[0012] Figure 7 It is a time chart showing the transition of the WGV opening degree during the catalyst early activation control in the engine control device of the modified example.

[0013] Figure 8 1 is a time chart showing the transition of the WGV opening degree during the catalyst early activation control in the engine control device according to another modified example. DETAILED DESCRIPTION

[0014] (First Embodiment)

[0015] Hereinafter, an engine control device according to a first embodiment will be described in detail with reference to the drawings.

[0016] <Structure of Engine Control Device>

[0017] First, refer to Figure 1 The structure of the engine control device of the present embodiment is described below. The engine 10, which is the control object of the engine control device of the present embodiment, includes a combustion chamber 11 in which a mixture is burned. In addition, the engine 10 includes: an intake passage 12 as an inlet passage for introducing intake air into the combustion chamber 11; and an exhaust passage 13 as an exhaust passage for exhausting exhaust gas from the combustion chamber 11. Moreover, the engine 10 also includes: an injector 14 that injects fuel into the intake air to form a mixture; and an ignition device 15 that ignites the mixture in the combustion chamber 11 by spark discharge. A throttle valve 16 is provided in a portion of the intake passage 12 that is on the downstream side of the compressor 21. The throttle valve 16 adjusts the amount of intake air introduced into the combustion chamber 11 according to the change in the opening. In addition, the engine 10 rotates a crankshaft 17 by the combustion of the mixture in the combustion chamber 11, thereby generating a driving force for the vehicle.

[0018] The engine 10 is provided with a turbocharger 20. The turbocharger 20 has a compressor 21 provided in the intake passage 12 and a turbine 22 provided in the exhaust passage 13. The compressor 21 is an impeller that compresses the intake air by rotating. The turbine 22 is an impeller that rotates by receiving the flow of exhaust gas. The compressor 21 and the turbine 22 are connected via a turbine shaft 23. Thus, the compressor 21 rotates in conjunction with the rotation of the turbine 22. In addition, a bypass passage 24 is provided in the exhaust passage 13, and the bypass passage 24 is a passage for passing exhaust gas while bypassing the turbine 22. The bypass passage 24 branches from the exhaust passage 13 at a portion of the exhaust passage 13 on the upstream side of the turbine 22. And the bypass passage 24 merges with the exhaust passage 13 at a portion of the exhaust passage 13 on the downstream side of the turbine 22. A WGV (wastegate valve) 25 for opening and closing the bypass passage 24 is provided at a merging position of the bypass passage 24 with the exhaust passage 13. That is, the WGV 25 is configured to open the bypass passage 24 that bypasses the turbine 22 provided in the exhaust passage 13 .

[0019] An air-fuel ratio sensor 18 is provided in the exhaust passage 13. The air-fuel ratio sensor 18 is a sensor for detecting the air-fuel ratio of the mixture after combustion in the combustion chamber 11. The air-fuel ratio sensor 18 is provided in the exhaust passage 13 at a portion downstream of the turbine 22 and downstream of the confluence position of the bypass passage 24. In addition, a catalyst device 19 is provided in the exhaust passage 13. The catalyst device 19 carries a catalyst for exhaust purification such as a three-way catalyst. The catalyst device 19 is provided in the exhaust passage 13 at a portion downstream of the air-fuel ratio sensor 18.

[0020] The engine 10 is controlled by an ECM (engine control module) 30 as an engine control device. The ECM 30 includes a processing device 31 and a storage device 32. The storage device 32 stores programs and data for engine control. The processing device 31 controls the engine 10 by reading the program from the storage device 32 and executing it. The detection results of various sensors for detecting the operating conditions of the engine 10 are input to the ECM 30. In addition to the above-mentioned air-fuel ratio sensor 18, the sensors that input the detection results to the ECM 30 include an air flow meter 33, an intake air temperature sensor 34, a water temperature sensor 35, a crank angle sensor 36, a boost pressure sensor 37, and an intake manifold pressure sensor 38. The air flow meter 33 is a sensor for detecting the flow rate of intake air flowing through the intake passage 12, that is, the intake air flow rate GA. The intake air temperature sensor 34 is a sensor for detecting the temperature of the intake air taken into the intake passage 12, that is, the intake air temperature THA. The water temperature sensor 35 is a sensor for detecting the temperature of the cooling water of the engine 10, that is, the engine water temperature THW. The crank angle sensor 36 is a sensor for detecting the rotation angle of the crankshaft 17, that is, the crank angle CRNK. The boost pressure sensor 37 is a sensor for detecting the pressure of the intake air in the portion of the intake passage 12 downstream of the compressor 21 and upstream of the throttle valve 16, that is, the boost pressure PB. The intake manifold pressure sensor 38 is a sensor for detecting the pressure of the intake air in the portion of the intake passage 12 downstream of the throttle valve 16, that is, the intake manifold pressure PM. Based on the detection results of these sensors, the ECM 30 controls the injection amount and injection timing of the fuel of the injector 14, the ignition timing of the ignition device 15, the throttle opening, the WGV opening, and the like.

[0021] <Catalyst Early Activation Control>

[0022] When the engine 10 is cold started, the ECM 30 performs a catalyst early activation control to open the WGV 25 and promote the activation of the catalyst device 19. In the catalyst early activation control, the activation of the catalyst device 19 is promoted in the following manner. In addition, the ECM 30 stops the engine 10 in a state where the WGV 25 is closed. Therefore, the WGV 25 is closed when the engine 10 is started.

[0023] When the WGV25 is closed, the exhaust gas flows through the turbine 22. When passing through the turbine 22, the flow of the exhaust gas becomes a swirling flow. Therefore, the exhaust gas spreads over a wide range after passing through the turbine 22. Therefore, when the WGV25 is closed, the exhaust gas is sprayed to a wide range at the front end of the catalyst device 19. In addition, the front end here refers to the end surface on the upstream side of the flow direction of the exhaust gas in the catalyst device 19.

[0024] On the other hand, when WGV25 is open, most of the exhaust gas flows through the bypass passage 24. The flow of the exhaust gas flowing out of the bypass passage 24 becomes a jet. Therefore, when WGV25 is open, the exhaust gas is concentratedly sprayed onto a portion of the front end of the catalyst device 19. That is, the heating performed by the exhaust gas is concentrated on a portion of the catalyst device 19. As a result, when WGV25 is open, a portion where the catalyst is activated is formed earlier in the catalyst device 19 than when the valve is closed. Therefore, in the catalyst early activation control, by keeping WGV25 in an open state, the period during which the catalyst device 19 cannot perform exhaust gas purification after the cold start of the engine 10 is shortened.

[0025] In addition, in the present embodiment, the WGV opening is defined as follows. The operating position of WGV25 when the bypass passage 24 is closed is set to the operating position of the WGV opening "0". And, the amount of movement of WGV25 from the operating position of the WGV opening "0" is set to the value of the WGV opening. In addition, in the following description, the maximum value of the control range of the WGV opening is recorded as the fully open opening. And, the WGV opening that is larger than "0" and smaller than the fully open opening is recorded as an intermediate opening.

[0026] Figure 2 1 shows the processing procedure of the catalyst early activation control routine executed by the ECM 30. The ECM 30 starts this routine at the same time when the start of the engine 10 is completed.

[0027] When this routine is started, the ECM 30 first determines in step S100 whether the catalyst device 19 is activated. In the present embodiment, this determination is made based on the intake air temperature THA and the engine water temperature THW at the time of engine start. When the ECM 30 determines that the catalyst device 19 is activated (S100: Yes), the processing of this routine at the time of the engine 10 start is terminated. In addition, after the end of this routine, the ECM 30 sets the target boost pressure according to the operating conditions of the engine 10, and starts the feedback control of the WGV opening so that the boost pressure PB becomes the target boost pressure.

[0028] On the other hand, when ECM30 determines that the catalyst device 19 is not activated (S100: No), the processing proceeds to step S110. Then, in step S110, ECM30 opens the WGV25 until the WGV opening reaches a predetermined first opening A1. In the present embodiment, the full opening is set to the first opening A1. In addition, when the WGV25 is opened as described above, the injection of exhaust gas into the catalyst device 19 is concentrated on a portion of the catalyst device 19. In addition, the temperature increase of the portion of the catalyst device 19 where the injection of exhaust gas is concentrated is promoted. In the following description, the portion at the front end of the catalyst device 19 and where the injection of exhaust gas is concentrated when the WGV opening is set to the first opening A1 is recorded as the first region R1.

[0029] Afterwards, ECM30 determines whether the activation of the first region R1 is completed at every predetermined control cycle (S120). That is, it determines whether the temperature of the first region R1 reaches the activation temperature of the catalyst. This determination is performed based on the time that has passed since the WGV25 was opened in step S110. Then, when ECM30 determines that the activation of the first region R1 is completed (S120: Yes), in step S130, the WGV opening is changed from the first opening A1 to a predetermined second opening A2. In the present embodiment, the second opening A2 is an intermediate opening. In addition, in the present embodiment, the processing from the opening of the WGV25 in step S110 to the transfer to step S130 corresponds to the first processing.

[0030] When the WGV opening is changed, the blowing direction of the exhaust gas from the bypass passage 24 changes. In addition, the region where the exhaust gas is blown at the front end of the catalyst device 19 is concentrated also changes. Therefore, by changing the WGV opening in step S130, the part of the catalyst device 19 heated by the exhaust gas moves. In the following description, the portion at the front end of the catalyst device 19 where the exhaust gas is blown when the WGV opening is set to the second opening A2 is described as the second region R2.

[0031] Afterwards, ECM30 determines whether the temperature rise of the second region R2 is completed at every predetermined control cycle (S140). The completion of the temperature rise here refers to, for example, the situation where the temperature of the second region R2 reaches the activation temperature of the catalyst. Even if the temperature of the second region R2 is lower than the activation temperature of the catalyst, the temperature rise can be regarded as completed when it rises to a temperature close to it. This judgment is made, for example, based on the elapsed time after the WGV opening is changed to the second opening A2 in step S130. Then, when ECM30 determines that the temperature rise of the second region R2 is completed (S140: Yes), it ends the processing of this routine. In addition, in the present embodiment, the processing from the change of the WGV opening in step S130 to the end of this routine corresponds to the second processing.

[0032] <Functions and Effects of Implementation Methods>

[0033] As described above, in this embodiment, after executing the first process of maintaining the WGV opening at the first opening A1, the second process of changing the WGV opening to the second opening A2 different from the first opening A1 is executed to perform catalyst early activation control.

[0034] Figure 3 The state of the catalyst device 19 and its surroundings during the implementation of the first treatment is shown. Figure 3 and the following Figure 4 , Figure 5 In the figure, the flow of exhaust gas sprayed to the catalyst device 19 is indicated by arrows. When the WGV25 is opened, most of the exhaust gas bypasses the turbine 22 and flows through the bypass passage 24. Therefore, the spraying of exhaust gas to the front end of the catalyst device 19 is concentrated in the first region R1. The first treatment continues until the activation of the catalyst in the first region R1 is completed. At the time point when the activation of the catalyst device 19 in the first region R1 is completed, it becomes a state that the exhaust gas can be purified even partially. However, when the catalyst early activation control is ended at the same time as the first treatment is completed, the following problems may sometimes occur.

[0035] Figure 4 For the comparative example in which the catalyst early activation control is terminated at the same time as the first treatment is completed, the state of the catalyst device 19 and its surroundings immediately after the control is completed is shown. At this time, the portion outside the first region R1 of the catalyst device 19 becomes a catalyst-inactivated state. When the WGV25 is closed in this state, the exhaust gas also flows to the catalyst-inactivated portion of the catalyst device 19. As a result, most of the exhaust gas is discharged to the outside air in an unpurified state, so the emission of the engine 10 deteriorates. Unlike the comparative example, in this embodiment, by performing the second treatment as described above after performing the first treatment, the deterioration of the emission of the engine 10 is suppressed.

[0036] Figure 5 The state of the catalyst device 19 and its surroundings during the implementation of the second treatment is shown. In the second treatment, the WGV opening is changed from the first opening A1 to the second opening A2. By changing the WGV opening, the direction of the exhaust gas from the bypass passage 24 toward the catalyst device 19 changes. And, as a result, the area heated by the exhaust gas moves from the first area R1 to the second area R2. As a result, the temperature of the second area R2 can be increased. Therefore, compared with the case where the WGV opening is fixed to a constant to perform the catalyst early activation control, the area where the catalyst temperature rises at the end of the control becomes larger. As a result, the deterioration of the emissions of the engine 10 immediately after the catalyst early activation control is completed is suppressed.

[0037] In addition, as described above, the second process may be continued until the activation of the catalyst in the second region R2 is completed, or may be terminated before that. In the latter case, if the catalyst temperature in the second region R2 rises to a certain level when the catalyst early activation control is terminated, the catalyst in the second region R2 is also activated in a short time after the control is terminated. Therefore, in such a case, the deterioration of the emission of the engine 10 immediately after the catalyst early activation control is also suppressed.

[0038] According to the engine control device of the present embodiment described above, the following effects can be achieved.

[0039] In the present embodiment, the catalyst early activation control is performed by performing a second process of making the WGV opening become a second opening A2 after performing a first process of maintaining the WGV opening at a first opening A1. By performing the second process, the region where the catalyst temperature rises is expanded. Thus, the deterioration of the exhaust performance of the engine 10 immediately after the catalyst early activation control is suppressed. Therefore, the engine control device of the present embodiment has the effect of improving the exhaust performance of the engine 10 during cold start.

[0040] (Second Embodiment)

[0041] Next, refer to Figure 6 The engine control device according to the second embodiment will be described in detail. In this embodiment, the same reference numerals are used for the same configurations as those in the above-described embodiment, and detailed description thereof will be omitted.

[0042] In the engine control device of the present embodiment, during the execution of the catalyst early activation control, the exhaust heat increase control is also executed. The exhaust heat increase control is a control to increase the heat of the exhaust gas flowing into the catalyst device 19. The exhaust heat increase control includes control to increase the temperature of the exhaust gas flowing into the catalyst device 19 by retarding the ignition timing, leaning the air-fuel ratio, etc. In addition, the exhaust heat increase control also includes control to increase the flow rate of the exhaust gas flowing into the catalyst device 19 by increasing the intake air amount, etc. In short, by executing such an exhaust heat increase control together with the catalyst early activation control, the activation of the catalyst device 19 can be further promoted.

[0043] In addition, the temperature increase of the exhaust gas flowing into the catalyst device 19 is achieved by increasing the heat loss of the engine 10. In addition, if the intake air is increased, the fuel injection amount needs to be increased accordingly. Therefore, when the exhaust heat increase control is performed, there is a contradiction that the fuel consumption performance of the engine 10 is reduced. On the other hand, before the first treatment is completed and the activation of the catalyst in the first region R1 is completed, the catalyst device 19 is in a state where it can hardly purify the exhaust gas. In contrast, the second treatment is implemented in a state where the catalyst in the first region R1 is activated, that is, in a state where the catalyst device 19 can purify the exhaust gas to a certain extent. Therefore, the temperature increase of the second region R2 in the second treatment has a time margin compared with the temperature increase of the first region R1 in the first treatment. Therefore, compared with performing the exhaust heat increase control throughout the execution of the catalyst early activation control, it is preferred to perform the exhaust heat increase control in the following manner. That is, the exhaust heat increase control is preferably performed during the implementation of the second treatment, suppressing the increase in the heat of the exhaust gas compared with the implementation of the first treatment. Alternatively, the exhaust heat increase control is preferably performed only during the implementation of the first treatment and not during the implementation of the second treatment.

[0044] Figure 6 An example of how the catalyst early activation control and the exhaust heat increase control are executed is shown. Figure 6 In the example of , exhaust heat increase control is performed by retarding the ignition timing. Figure 6 (A) shows the change of WGV opening degree. Figure 6 (B) shows the change of the ignition delay amount. In addition, the ignition delay amount represents the delay amount of the ignition timing caused by the exhaust heat increase control. Figure 6 In the process, at time t0, the catalyst early activation control and the exhaust heat increase control are started. Then, in the catalyst early activation control, the first process of maintaining the WGV opening at the first opening A1 is implemented during the period from time t0 to time t1, and the second process of changing the WGV opening to the second opening A2 is implemented during the period from time t1 to time t2. On the other hand, the ignition delay amount is maintained at a predetermined positive value during the implementation of the first process from time t0 to time t1, and is "0" during the implementation of the second process from time t1 to time t2. That is, in Figure 6 In the example of FIG. 1 , the exhaust heat increase control based on the retardation of the ignition timing is performed only during the implementation of the first process.

[0045] By executing the exhaust heat increase control during the implementation of the first process, the time required for the start of exhaust gas purification by the catalyst device 19 is shortened. On the other hand, since the exhaust heat increase control is not executed during the implementation of the second process, the reduction in fuel efficiency performance of the engine 10 associated with the execution of the control is suppressed. Figure 6 As shown by the dotted line in (B), during the implementation of the second treatment, the ignition delay amount can be made smaller than the ignition delay amount during the implementation of the first treatment period to perform the exhaust heat increase control. In this case, the same effect can be obtained. In addition, if the activation of the catalyst device 19 takes priority over the fuel consumption performance, the ignition delay amount can also be kept at the same value as that during the implementation of the first treatment during the implementation of the second treatment to perform the exhaust heat increase control.

[0046] (Modification of the above embodiment)

[0047] The above-mentioned embodiment can be implemented by changing the following aspects. The above-mentioned embodiment and the following modified examples can be implemented in combination with each other within the scope of no technical contradiction.

[0048] <About the First Opening Degree A1 and the Second Opening Degree A2>

[0049] In the above embodiment, the first opening degree A1 is set as the maximum opening degree, but an intermediate opening degree may be set as the first opening degree A1. In this case, the second opening degree A2 is an intermediate opening degree smaller than the first opening degree A1 or an opening degree larger than the first opening degree A1.

[0050] <About Completion Determination of First Process and Second Process>

[0051] In the above embodiment, the first process and the second process are completed based on the elapsed time from the start of the first process and the second process. The time required for activation and temperature rise of the catalyst in the first process and the second process varies according to the catalyst temperature and the outside air temperature at the start of the process. Therefore, the implementation time of the first process and the second process can also be made variable based on the engine water temperature THW and the intake air temperature THA when the engine 10 is started.

[0052] The amount of heat received by the catalyst device 19 from the exhaust gas is related to the flow rate of the exhaust gas flowing into the catalyst device 19. Furthermore, the flow rate of the exhaust gas is related to the intake air flow rate GA. Therefore, the completion determination of the first process and the second process may be performed based on the integrated value of the intake air flow rate GA from the start of the process.

[0053] Furthermore, the completion determination of the first process and the second process may be performed based on the estimated values ​​of the catalyst temperatures of the first region R1 and the second region R2. The catalyst temperatures of the first region R1 and the second region R2 can be estimated based on the engine water temperature THW, the outside air temperature, the intake air flow rate GA, the ignition timing, etc. when the engine 10 is started. Furthermore, the catalyst temperatures of the first region R1 and the second region R2 may be detected by a sensor, and the completion determination of the first process and the second process may be performed based on the detected values ​​of the catalyst temperatures.

[0054] <Regarding Changes in WGV Opening Degree in Second Process>

[0055] In the above embodiment, the second process is to maintain the WGV opening at the second opening A2. The second process may be to gradually change the WGV opening from the first opening A1 to a predetermined third opening A3 different from the first opening A1.

[0056] Figure 7 The change in the WGV opening during the execution of the catalyst early activation control in this case is shown. Figure 7 In the case of the catalyst early activation control starting at time t0. Then, during the period from this time t0 to the subsequent time t1, the first treatment of maintaining the WGV opening at the first opening A1 is implemented. Then, during the period from the time t1 to the subsequent time t2, the second treatment is implemented. And, from the time t1 to the time t2, the WGV opening is gradually changed from the first opening A1 to the third opening A3. In this case, during the implementation of the second treatment, the second region R2 where the exhaust gas injection is concentrated gradually moves. Therefore, in the second treatment, the catalyst temperature over a wide range can be raised.

[0057] Alternatively, the second process may be a process of repeatedly increasing and decreasing the opening degree of the WGV 25 within a predetermined opening degree range. Figure 8 The change in the WGV opening during the execution of the catalyst early activation control in this case is shown. Figure 8 In the example, the first process is performed during the period from time t0 to time t1, and the second process is performed during the period from time t1 to time t2. Figure 8 In this case, during the implementation of the second treatment, the opening of WGV25 is repeatedly increased and decreased within the range from the first opening A1 to the third opening A3. In this case, during the implementation of the second treatment, the second region R2 where the exhaust gas injection is concentrated gradually moves, so that the catalyst temperature in a wide range can be raised.

[0058] In addition, Figure 7 , Figure 8In the embodiment, the third opening degree A3 is set to an intermediate opening degree, but the third opening degree A3 may also be set to "0".

[0059] <About Engine Control Unit>

[0060] The engine control device is not limited to a device that includes a processing device 31 and a storage device 32 and executes software processing. For example, a dedicated hardware circuit such as an ASIC (Application Specific Integrated Circuit) that processes at least a part of the software processing executed in the above embodiment may be provided. That is, the engine control device can be any of the following structures (a) to (c). (a) A processing device that executes all the above processing according to a program and a program storage device such as a ROM that stores the program. (b) A processing device and a program storage device that execute a part of the above processing according to a program, and a dedicated hardware circuit that executes the remaining processing. (c) A dedicated hardware circuit that executes all the above processing. Here, the software execution device and the dedicated hardware circuit that include the processing device and the program storage device may be multiple. That is, the above processing can be executed by a processing circuit (processing circuitry) that includes at least one of one or more software execution devices and one or more dedicated hardware circuits. The program storage device, i.e., the computer-readable medium, includes any available medium that can be accessed by a general-purpose or dedicated computer.

Claims

1. An engine control device, applied to an engine, the engine comprising: a turbine, arranged in an exhaust passage; a bypass passage, branching from the exhaust passage at a portion of the exhaust passage on the upstream side of the turbine, and merging with the exhaust passage at a portion of the exhaust passage on the downstream side of the turbine; an exhaust bypass valve, arranged at a merging position of the bypass passage merging with the exhaust passage; and a catalyst device for exhaust purification, arranged at a portion of the exhaust passage on the downstream side of the merging position, wherein the engine control device is configured to perform catalyst early activation control for promoting activation of the catalyst device by maintaining the exhaust bypass valve in an open state when the engine is cold started, wherein: The engine control device comprises a processing circuit, The processing circuit is configured to perform the catalyst early activation control by performing a first process for maintaining the opening of the wastegate valve at a predetermined first opening, and performing a second process for changing the opening of the wastegate valve to an opening different from the first opening after performing the first process. The second process is a process of repeatedly increasing and decreasing the opening of the waist gate valve within a predetermined opening range.

2. The engine control device according to claim 1, wherein: The processing circuit is configured to execute exhaust heat increasing control for increasing the heat of exhaust gas flowing into the catalyst device during execution of the catalyst early activation control.

3. The engine control device according to claim 2, wherein: The processing circuit is configured to perform the exhaust gas heat increase control by suppressing an increase in the amount of heat of the exhaust gas during the execution of the second process compared to the execution of the first process.

4. The engine control device according to claim 3, wherein: The processing circuit is configured to execute the exhaust heat increase control only during the implementation of the first process.

5. An engine control method, comprising: a method for controlling an engine having an exhaust bypass valve and a catalyst device for exhaust purification, wherein the exhaust bypass valve is configured to open a bypass passage that bypasses a turbine disposed in an exhaust passage, and the catalyst device is disposed in a portion of the exhaust passage that is downstream of the exhaust bypass valve, wherein: The engine control method comprises: When the engine is cold started, performing a first process of injecting exhaust gas into a first region of the catalyst device by maintaining the opening of the wastegate valve at a predetermined first opening; and After the first process is performed, a second process is performed to inject exhaust gas into a second region of the catalyst device different from the first region by maintaining the opening of the wastegate valve at a second opening different from the first opening. The second process is a process of repeatedly increasing and decreasing the opening of the waist gate valve within a predetermined opening range.

Images