Vehicle exhaust system catalytic converter control device

Abstract

To manage a catalyst device used in an exhaust system of an engine of a vehicle while reducing a burden on a driver of the vehicle.SOLUTION: A management device of an exhaust system catalyst of a vehicle 1 includes catalyst devices 5-7 used in an exhaust system 4 of an engine 3, differential pressure sensors 10-12 for detecting an accumulation state of an exhaust-containing object in the catalyst devices 5-7, a control unit 21 for executing output control for removing the exhaust-containing object from the catalyst devices, and outside-vehicle sensors 13, 14 for detecting the circumference of the vehicle 1. The control unit 21 determines the accumulation state of the exhaust-containing object in the catalyst devices 5-7 in correspondence with the detection result of the differential pressure sensors 10-12. The control unit 21 determines, on the basis of the detection result of the circumference of the vehicle 1 by the outside-vehicle sensors 13, 14, whether the vehicle 1 is in a traveling environment in which output control for removing can be executed or not, and executes the output control for removing so as to improve the state of the catalyst devices 5-7 during traveling of the vehicle 1.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] This invention relates to a control device for the catalytic converter in a vehicle's exhaust system. [Background technology]

[0002] In vehicles such as automobiles, an engine is used to generate the driving force necessary for propulsion. Engines can be configured in various ways, including those that use a carburetor to inject gasoline into the air to create a fuel-air mixture, which is then drawn into the engine, or those that directly inject gasoline into the engine's combustion chamber. Furthermore, some engines use a reduced amount of gasoline in the combustion chamber for lean combustion. In contrast, conventional gasoline engines use a rich mixture of gasoline in the combustion chamber for combustion.

[0003] These engines require the combustion gases to be exhausted outside the engine. Furthermore, engine exhaust tends to produce nitrogen oxides or soot. In particular, direct injection engines capable of lean combustion tend to generate large amounts of nitrogen oxides or soot. Furthermore, regardless of whether lean combustion is used or not, gasoline-fueled engines can produce sulfur compounds. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2010-084686 [Patent Document 2] Japanese Patent Publication No. 2013-113215 [Patent Document 3] Japanese Patent Publication No. 2010-059832 [Overview of the project] [Problems that the invention aims to solve]

[0005] Therefore, the exhaust system of a vehicle's engine uses a catalytic converter to capture nitrogen oxides, soot, or sulfur compounds. However, exhaust contaminants such as nitrogen oxides, soot, or sulfur compounds accumulate in the catalytic converter. When a large amount of exhaust contaminants accumulate in the catalytic converter, it needs to be replaced. When the catalytic converter is not functioning properly, the driver needs to take the vehicle to a repair shop such as a dealer. Replacing the catalytic converter, in particular, is time-consuming and expensive. Furthermore, driving with a large amount of exhaust gas particles accumulated in the catalytic converter may reduce engine performance. Thus, in vehicles, it is desirable to manage the catalytic converter used in the exhaust system of the vehicle's engine. In particular, in vehicles, it is desirable to manage the catalytic converter in a way that reduces the frequency of replacement, if possible.

[0006] Patent documents 1 to 3 disclose techniques for improving the accumulation of exhaust gases in catalytic converters. However, in order to improve the accumulation of exhaust gases in the catalytic converter, it is basically necessary to maintain a high engine exhaust temperature. Patent Document 1 discloses methods for automatically and manually controlling the accumulation of exhaust gases in a catalytic converter. Patent Document 2 discloses a method for controlling the accumulation of exhaust gas components in a catalytic converter based on the operation of a driver switch. In these cases, the driver must determine for themselves whether the current driving environment is one in which removal control can be implemented. The driver is required to have sufficient awareness to determine whether or not it is appropriate to implement removal control while driving, and to make that determination. In addition, Patent Document 3 discloses changing the guidance route of an automobile in order to execute control for improving the accumulation state of exhaust gas components in a catalytic device. In this case, the driver feels uncomfortable because they are guided along a route different from the usual one. The driver may not drive along a route that takes more time and cost than usual. For a driver who does not recognize that it is necessary to remove exhaust gas components from the catalytic device, it is incomprehensible to be guided along a long route deliberately, and it is only stressful. In any case, the burden on the driver is great.

[0007] Thus, in a vehicle, it is desirable to manage a catalytic device used in an exhaust system of a vehicle engine while reducing the burden on the driver.

Means for Solving the Problems

[0008] An exhaust system catalyst management device for a vehicle according to one aspect of the present invention includes Vehicle a catalytic device used in an exhaust system of an engine, a differential pressure sensor that detects an accumulation state of exhaust gas components in the catalytic device based on a pressure difference between an inlet pressure and an outlet pressure of the catalytic device, and Records a control unit that executes output control for removal to improve the accumulation state, and an outside-vehicle sensor that detects the surroundings of the vehicle. The control unit determines the accumulation state of the exhaust gas components in the catalytic device according to the detection result of the differential pressure sensor, and determines whether it is a driving environment in which output control for removal can be executed based on the detection result of the surroundings of the vehicle by the outside-vehicle sensor, and executes output control to improve the accumulation state of the exhaust gas components in the catalytic device. to exhaust gas components but accumulation doing state Whether or not and executes output control for removal based on the detection result of the surroundings of the vehicle by the outside-vehicle sensor. The aforementioned executable Driving on a regular road or highway driving environment to exhaust gas components but accumulation If this is the case and it is determined that the vehicle is traveling on the expressway, the engine is made lean to increase the exhaust temperature while the vehicle is traveling at high speed. pre Records accumulation state improvement For the removal of the above for highways execute output control Furthermore, if exhaust contaminants have accumulated in the catalytic converter and it is determined that the vehicle is traveling on the public road, the system performs output control for removal on public roads to improve the accumulation state by leaning the engine to increase the exhaust temperature when the vehicle starts moving from a stop.

Effects of the Invention

[0009] In this invention, the accumulation state of exhaust contaminants in a catalytic converter used in the exhaust system of a vehicle engine is detected by a differential pressure sensor based on the pressure difference between the inlet and outlet pressures of the catalytic converter. The control unit then determines the accumulation state of exhaust contaminants in the catalytic converter according to the detection result of the differential pressure sensor. This makes it possible to manage the accumulation state of exhaust contaminants in the catalytic converter of a vehicle's exhaust system. In particular, in this invention, output control for removal is performed during vehicle operation to improve the accumulation state of exhaust contaminants in the catalytic converter, based on the result of determining the state of exhaust contaminant accumulation in the catalytic converter. As a result, the accumulation state of exhaust contaminants in the vehicle's catalytic converter can be improved by the operation of the vehicle. Exhaust contaminants such as nitrogen oxides, soot, or sulfur compounds contained in the exhaust become less likely to accumulate in large quantities in the vehicle's catalytic converter. Direct injection gasoline engines capable of lean combustion tend to have higher levels of these exhaust contaminants compared to engines that do not perform lean combustion or engines that do not directly inject gasoline. By using this invention, exhaust contaminant accumulation becomes less likely even in catalytic converters used in the exhaust system of direct injection gasoline engines capable of lean combustion. Furthermore, this embodiment includes an external sensor that detects the area around the vehicle. The control unit also determines, based on the detection results of the external sensor, whether the driving environment is suitable for executing output control for removal. When the control unit determines that the driving environment is suitable for executing output control for removal, it executes output control for removal to improve the accumulation of exhaust gases in the catalytic converter. As a result, the control unit executes output control for removal, which is performed while the vehicle is in motion, only when it determines that the driving environment is suitable for executing output control for removal. The driver does not need to determine for themselves whether the current driving environment is suitable for executing output control for removal. In addition, output control for removal can be executed when the driving environment is safe. Thus, the present invention makes it possible to manage the catalytic converter used in the exhaust system of a vehicle's engine while reducing the burden on the driver. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is an explanatory diagram of an automobile to which an exhaust system catalyst control device according to the first embodiment of the present invention is applied. [Figure 2] Figure 2 is a flowchart of the catalyst management control performed by the control unit shown in Figure 1. [Figure 3] Figure 3 shows an example of the PM catalyst replacement notification screen displayed on the meter panel in Figure 1 during the process shown in Figure 2. [Figure 4] Figure 4 shows the engine check lamp screen displayed on the meter panel in Figure 1 during the process shown in Figure 2. [Figure 5] Figure 5 shows an example of a PM removal process warning notification screen displayed on the meter panel in Figure 1 during the process shown in Figure 2. [Figure 6] Figure 6 shows the PM removal warning lamp screen displayed on the meter panel in Figure 1 during the process shown in Figure 2. [Figure 7] Figure 7 is a flowchart of the output control system, as shown in Figure 1, that supports self-propelled removal processing. [Figure 8] Figure 8 shows an example of the PM accumulation status display screen shown on the meter panel in Figure 1 during the process in Figure 7. [Figure 9] Figure 9 is an example of a detailed flowchart for determining the vehicle's driving environment in the output control shown in Figure 7. [Figure 10] Figure 9 is an example of a detailed flowchart for determining the end of PM removal control in the output control shown in Figure 7. [Figure 11] Figure 11 shows an example of a success notification screen for the PM removal process displayed on the meter panel in Figure 1, during the process shown in Figure 10. [Figure 12] Figure 12 shows an example of a notification screen indicating the failure of the PM removal process, displayed on the meter panel in Figure 1, during the process shown in Figure 10. [Figure 13] Figure 13 is an explanatory diagram illustrating an example of the relationship between the PM accumulation rate of a PM catalyst device and the pressure difference detected by a differential pressure sensor. [Figure 14]Figure 14 shows an example of a notification screen for the replacement of a catalyst device for sulfur compounds, displayed on the meter panel in Figure 1, as a result of the processing shown in Figure 2 in the second embodiment of the present invention. [Figure 15] Figure 15 shows an example of a warning notification screen for the sulfur compound removal process displayed on the meter panel in Figure 1, based on the process shown in Figure 2 in the second embodiment of the present invention. [Figure 16] Figure 16 is an example of a detailed flowchart for determining the termination of sulfur compound removal control in the second embodiment of the present invention. [Figure 17] Figure 17 shows an example of a success notification screen for the sulfur compound removal process displayed on the meter panel in Figure 1, during the process shown in Figure 16. [Figure 18] Figure 18 shows an example of a notification screen indicating the failure of the sulfur compound removal process, as displayed on the meter panel in Figure 1, during the process shown in Figure 16. [Modes for carrying out the invention]

[0011] Embodiments of the present invention will be described below with reference to the drawings.

[0012] [First Embodiment] Figure 1 is an explanatory diagram of an automobile 1 to which an exhaust system catalyst control device according to the first embodiment of the present invention is applied. Automobile 1 in Figure 1 is an example of a vehicle. Automobile 1 may not only be capable of driving based on the driver's input, but may also be capable of driving with driver assistance to support the driver's input, or driving autonomously.

[0013] Automobile 1 has a body 2. An engine 3 is installed in the front of the body 2. The engine 3 may be, for example, a direct injection gasoline engine. The engine 3 may also use a carburetor or the like to inject gasoline into the air to create a fuel-air mixture, and then draw the created mixture into the engine 3. And in engine 3, in order to improve environmental performance in recent years, not only combustion in a state where conventional gasoline is supplied rich, but also lean combustion with diluted gasoline may be used. An exhaust system 4 is connected to the engine 3 by an exhaust pipe. The air-fuel mixture burned in the engine 3 is exhausted to the outside of the vehicle through the exhaust pipe. The exhaust of this gasoline engine may contain exhaust constituents such as nitrogen oxides such as NO X , X , X , X , X , X , , ,

[0016] , , and sulfur compounds. Therefore, various catalytic devices are provided in the exhaust system 4. In the exhaust system 4 of the present embodiment, from the side of the engine 3, a three-way catalytic device 5, a first NO X storage reduction catalytic device 6, and a second NO X storage reduction catalytic device 7 are provided with three catalytic devices.

[0014] The three-way catalytic device 5 removes hydrocarbons, carbon monoxide, and nitrogen oxides from the exhaust. Further, the three-way catalytic device 5 may have a particulate filter and capture and accumulate soot and the like contained in the exhaust. Such a three-way catalytic device 5 is likely to accumulate PM (particulate matter) such as nitrogen oxides and soot. The three-way catalytic device 5 functions as a PM catalytic device.

[0015] The first NO X storage reduction catalytic device 6, or the second NO X storage reduction catalytic device 7 reduces NO by Lean NO X Trap. However, sulfur compounds may accumulate in the NO X storage reduction catalytic device that reduces NO by Lean NO X Trap. X X

[0016] With these multiple catalytic devices, nitrogen oxides, soot, sulfur compounds, etc. are well removed from the exhaust of the automobile 1. Particularly, in a direct injection engine capable of lean combustion, a large amount of nitrogen oxides or soot is likely to be generated, but the multiple catalytic devices can well remove these from the exhaust. Furthermore, regardless of whether lean combustion is used or not, sulfur compounds are generated in the exhaust of engine 3 which uses gasoline as fuel, but multiple catalytic converters can effectively remove these from the exhaust.

[0017] However, exhaust gas components such as nitrogen oxides, soot, or sulfur compounds removed from the exhaust gas can accumulate in the catalytic converter, some of which may undergo alteration. In particular, direct injection engines capable of lean combustion are prone to generating nitrogen oxides and soot. For example, if short-distance driving is repeated before the engine 3 has warmed up, nitrogen oxides and soot may accumulate on the three-way catalytic converter 5 to a degree that requires removal.

[0018] Furthermore, if a large amount of exhaust contaminants accumulate in the catalytic converter, it becomes necessary to replace the catalytic converter. Also, if the vehicle is driven with a large amount of exhaust contaminants accumulated in the catalytic converter, the performance of the engine 3 may deteriorate. In these cases, the driver will need to take the vehicle 1 to a repair shop such as a dealer. Replacing the catalytic converter will incur time and expense for the driver. In vehicles such as automobile 1, it is desirable to manage the catalytic converter used in the exhaust system 4 of the vehicle's engine 3. In particular, in automobile 1, it is desirable to manage the catalytic converter in a way that reduces the number of times the catalytic converter needs to be replaced, if possible. Furthermore, drivers of trucks and other vehicles using diesel engines are expected to have knowledge and awareness that exhaust contaminants can accumulate in catalytic converters and that their removal is necessary. However, it is thought that most ordinary drivers do not possess this knowledge or awareness. In managing catalytic converters, it is desirable that even these ordinary drivers be able to manage them properly. In managing catalytic converters, it is desirable that drivers be able to manage them appropriately while reducing their burden.

[0019] The automobile 1 of this embodiment has a first differential pressure sensor 10, a second differential pressure sensor 11, a third differential pressure sensor 12, and a control unit 21 to which these are connected, in order to manage the exhaust system catalytic converter. The control unit 21 is further connected to an external camera 13, a Lidar 14, a speed sensor 15, a GNSS receiver 16, a timer 17, a meter panel 18, a speaker 19, and a memory 20. The first differential pressure sensor 10, the second differential pressure sensor 11, and the third differential pressure sensor 12 are external sensors 13 and 14.

[0020] The first differential pressure sensor 10 detects the pressure at the inlet and outlet of the three-way catalytic converter 5 and detects the pressure difference between the inlet and outlet pressures of the three-way catalytic converter 5. The pressure difference between the inlet and outlet pressures of the three-way catalytic converter 5 increases as the amount of exhaust gas content accumulated in the three-way catalytic converter 5 increases. The first differential pressure sensor 10 may also use the pressure difference when there is no exhaust gas content accumulated in the three-way catalytic converter 5 as a reference and detect the difference from that as the pressure difference. In this way, the first differential pressure sensor 10 can detect the state of exhaust gas content accumulation in the three-way catalytic converter 5 based on the pressure difference between the inlet pressure and the outlet pressure of the three-way catalytic converter 5.

[0021] The second differential pressure sensor 11 is the first NO X The pressure at the inlet and outlet of the storage-reduction catalyst device 6 is detected, and the first NO X The pressure difference between the inlet and outlet pressures of the storage reduction catalyst device 6 is detected. X The pressure difference between the inlet and outlet pressures of the storage reduction catalyst device 6 is the first NO X The second differential pressure sensor 11 increases as the amount of exhaust gas content accumulated in the storage-reduction catalyst device 6 increases. X The pressure difference may be detected by using the pressure difference when no exhaust gas contents have accumulated in the storage-reduction catalyst device 6 as a reference. In this way, the second differential pressure sensor 11 detects the first NO X The pressure difference between the inlet pressure and outlet pressure of the storage reduction catalyst device 6 causes the first NO X The accumulation state of exhaust gas components in the storage and reduction catalyst device 6 can be detected.

[0022] The third differential pressure sensor 12 is the second NO XThe pressure at the inlet and outlet of the storage reduction catalyst device 7 is detected, and the second NO X The pressure difference between the inlet and outlet pressures of the storage reduction catalyst device 7 is detected. X The pressure difference between the inlet and outlet pressures of the storage reduction catalyst device 7 is the second NO X The amount of exhaust gas content accumulated in the storage and reduction catalyst device 7 increases, and the third differential pressure sensor 12 detects the second NO X The pressure difference may be detected by using the pressure difference when no exhaust gas contents have accumulated in the storage reduction catalyst device 7 as a reference. In this way, the third differential pressure sensor 12 detects the second NO X The pressure difference between the inlet and outlet pressures of the storage-reduction catalyst device 7 causes the second NO X The accumulation state of exhaust gas components in the storage and reduction catalyst device 7 can be detected.

[0023] The external camera 13 is mounted facing outwards in the vehicle 1 and detects the surroundings of the vehicle 1 by imaging as an external sensor. Preferably, the external camera 13 is capable of imaging the front side of the vehicle 1, which is the direction of travel, and the rear side of the vehicle 1. Multiple external cameras 13 may be installed in the vehicle 1. The external camera 13 may also analyze the captured images to detect predetermined objects included in the captured images. This allows the external camera 13 to detect other vehicles 1, such as a preceding vehicle in front of it or a following vehicle behind it, as well as traffic lights, stop lines, etc. The external camera 13 functions as an external sensor that detects the surroundings of the vehicle 1.

[0024] Lidar14, acting as an external sensor, outputs light outward from the vehicle 1 and generates spatial information detecting the area around the vehicle 1 based on the reflected light. Lidar14 may analyze the external spatial information and detect predetermined objects included in the spatial information. This allows Lidar14 to detect other vehicles 1, such as a preceding vehicle in front of it or a following vehicle behind it, as well as traffic lights, stop lines, etc. Lidar14 functions as an external sensor that detects the area around the vehicle 1.

[0025] The speed sensor 15 detects the speed of the vehicle 1. Alternatively, the speed sensor 15 may detect the speed of the vehicle 1 by using an acceleration sensor and integrating the detected acceleration over time.

[0026] The GNSS receiver 16 receives radio waves from multiple GNSS satellites (not shown) and generates the vehicle's position and time based on the time and position information of the satellites contained in the radio waves. The GNSS satellites may include zenith satellites. The GNSS receiver 16 may also receive radio waves from ground-based fixed stations and base stations to correct the generated vehicle's position and time.

[0027] Timer 17 measures, for example, time or period. The time measured by Timer 17 may be calibrated by the time measured by GNSS receiver 16.

[0028] The meter panel 18 is installed in the vehicle body 2 of the automobile 1 in a passenger compartment (not shown) where the driver and other occupants are seated. The meter panel 18 is a display device installed in the automobile 1. The meter panel 18 may be installed in front of the seat where the driver sits. This allows the driver to visually check the meter panel 18 while driving the automobile 1. The automobile 1 may also be equipped with other display devices besides the meter panel 18, such as a center console touch panel.

[0029] The speaker 19 is installed in the passenger compartment (not shown) of the automobile 1. The speaker 19 may output, for example, a warning sound, an operation start sound, an operation end sound, a synthesized sound, and the like.

[0030] Memory 20 stores programs for control, which will be described later, and various data used when the program is executed. Memory 20 may consist of, for example, non-volatile semiconductor memory, RAM, HDD, etc. Various data used when the program is executed may include, for example, a removal flag 26 and high-precision map data 27 that can be used for route guidance of the automobile 1. The high-precision map data 27 may include information on road shapes and information on traffic lights around the roads.

[0031] The control unit 21 is a computer device, such as an ECU, that can read and execute programs. The control unit 21 reads and executes the program stored in the memory 20. For example, the control unit 21, in order to manage the catalytic converter, determines the accumulation state of exhaust gas components in the various catalytic converters described above, based on the detection result of any of the differential pressure sensors 10 to 12 among the first differential pressure sensors 10 to the third differential pressure sensors 12 described above. Furthermore, if exhaust contaminants are accumulating in the catalytic converter, the control unit 21, while the vehicle 1 is running, executes output control for removal, which is different from the normal performance-prioritizing output control, in order to improve the state of exhaust contaminant accumulation in the catalytic converter. Furthermore, when the control unit 21 performs output control for removal, it may display the status of the catalyst device involved in the process on the meter panel 18.

[0032] Figure 2 is a flowchart of the catalyst management control performed by the control unit 21 in Figure 1. The control unit 21 repeatedly performs the catalyst management control shown in Figure 2. In this embodiment, we will explain using the case where the exhaust gas content accumulated in the catalytic device involved in the treatment is mainly nitrogen oxides and soot, which are particulate matter (PM). In the above-mentioned catalytic devices, for example, the three-way catalytic converter 5 functions as a PM catalytic converter.

[0033] In step ST1, the control unit 21 acquires the detected values ​​from the differential pressure sensors 10 to 12 corresponding to the catalytic device to be controlled. For example, when controlling a three-way catalytic converter 5, the control unit 21 only needs to acquire the detected pressure difference between the input pressure and output pressure of the first differential pressure sensor 10. First NO X When controlling the storage reduction catalyst device 6, the control unit 21 only needs to acquire the detected pressure difference between the input pressure and output pressure of the second differential pressure sensor 11. Second NO X When controlling the storage reduction catalyst device 7, the control unit 21 only needs to acquire the detected pressure difference between the input pressure and output pressure of the third differential pressure sensor 12. The control unit 21 may repeatedly execute the catalyst management control shown in Figure 2 for each of the multiple catalyst devices installed in the automobile 1, one by one in sequence. Furthermore, if only PM (particulate matter) is to be removed, the control unit 21 may repeatedly execute the catalyst management control shown in Figure 2 for at least the three-way catalyst device 5.

[0034] In step ST2, the control unit 21 compares the acquired differential pressure detection value with the catalytic converter replacement threshold to determine whether the catalytic converter is in a state of accumulation requiring replacement. The catalytic converter replacement threshold may be, for example, the differential pressure detection value when the catalytic converter is in a state of PM accumulation requiring replacement. Based on the detection results of the differential pressure sensors 10-12, which are external sensors, the control unit 21 determines the state of exhaust gas accumulation in the catalytic converter. If the differential pressure detection value is greater than or equal to the replacement threshold, the control unit 21 proceeds to step ST3 to prompt the replacement of the catalytic converter. If the differential pressure detection value is not greater than or equal to the replacement threshold, the catalytic converter does not need to be replaced, and the control unit 21 proceeds to step ST5.

[0035] In step ST3, the control unit 21 generates a "Dealer Replacement Required" display screen that notifies the user that the catalytic converter needs to be replaced, and displays it on the meter panel 18. The control unit 21 may also output sound from the speaker 19. Figure 3 shows an example of a PM catalyst replacement notification screen 30 displayed on the meter panel 18 in Figure 1 during the process shown in Figure 2. The control unit 21 may display the PM catalyst replacement notification screen 30 on the meter panel 18. The PM catalyst replacement notification screen 30 in Figure 3 displays a message notifying the driver that the PM catalyst needs to be replaced, along with a driver-operable dealer guidance button 31. This allows the driver to recognize that the three-way catalytic converter 5, which functions as a PM catalyst, needs to be replaced while driving or while riding in the vehicle 1. Figure 4 shows the engine 3 check lamp screen 32 displayed on the meter panel 18 in Figure 1 during the process shown in Figure 2. The control unit 21 may display the engine 3 check lamp screen 32 shown in Figure 4 on the meter panel 18. This allows the driver to recognize that the engine 3 needs to be checked while driving or while riding in the vehicle 1. Based on the display of the engine 3 check lamp screen 32 in the vehicle 1 brought in, a repair shop such as a dealer can investigate the malfunction of the engine 3 and replace the three-way catalytic converter 5, which functions as a PM catalyst.

[0036] In step ST4, the control unit 21 displays information about dealers that can replace the catalyst unit. The control unit 21 may also display information about dealers in step ST4 only if the dealer information button 31 is pressed on the PM catalyst unit replacement notification screen 30 in Figure 3. For example, the control unit 21 may use the map data 27 stored in the memory 20 to search for a route from the current location determined by the GNSS receiver 16 to the location of the dealer, and display the route to the dealer on the meter panel 18. Furthermore, the control unit 21 may display contact information such as the dealer's phone number and short messages, as well as information about the vehicle 1, on the meter panel 18. In this way, the control unit 21 can display on the meter panel 18 that the catalytic converter needs to be replaced, and then display instructions for maintenance operators on the meter panel 18. Subsequently, the control unit 21 terminates this control.

[0037] In step ST5, the control unit 21 compares the acquired differential pressure detection value with the catalytic converter's warning threshold in order to determine whether maintenance of the catalytic converter is necessary based on the differential pressure detection value. If the amount of PM accumulated in the catalytic converter is small, the driver may be able to remove the accumulated PM from the catalytic converter by driving the vehicle 1 at a predetermined speed. The warning threshold may be, for example, the differential pressure detection value when the amount of PM accumulated in the catalytic converter is such that it can be removed by driving. This allows the control unit 21 to determine the state of exhaust gas accumulation in the catalytic converter according to the detection results of the differential pressure sensors 10 to 12. The control unit 21 can determine whether improvement is possible by the driver's actions while driving by setting a warning threshold (second threshold) that is smaller than the exchange threshold (first threshold) of the pressure difference at which improvement is deemed impossible by the driver's actions while driving. If the differential pressure detection value is equal to or greater than the warning threshold, the control unit 21 proceeds to step ST6 to encourage the removal of PM from the catalytic converter. If the differential pressure detection value is not equal to or greater than the warning threshold, there is no need to remove PM from the catalytic converter, and this control is terminated.

[0038] In step ST6, the control unit 21 generates a display screen warning that maintenance of the catalytic converter is required and displays it on the meter panel 18. The control unit 21 may also output sound from the speaker 19. Figure 5 shows an example of a PM removal process warning notification screen 33 displayed on the meter panel 18 in Figure 1 during the process shown in Figure 2. The control unit 21 may display the PM removal process warning notification screen 33 on the meter panel 18. The PM removal process warning notification screen 33 in Figure 5 displays a message warning about the PM removal process, along with a driver-operated dealer processing button 34 and a self-driving processing button 35 that allows the driver to perform the process by driving the vehicle themselves. This allows the driver to recognize that maintenance is required for PM removal of the three-way catalytic converter 5, which functions as a PM catalyst. Figure 6 shows the PM removal warning lamp screen 36 displayed on the meter panel 18 in Figure 1 during the process shown in Figure 2. The control unit 21 may display the PM removal warning lamp screen 36 shown in Figure 6 on the meter panel 18. This allows the driver to recognize that maintenance is needed for the catalytic converter while driving or while riding in the vehicle 1. Based on the display of the PM removal warning lamp screen 36 in the vehicle 1 brought in, a repair shop such as a dealer can examine the catalytic converter and perform maintenance on the three-way catalytic converter 5, which functions as a PM catalytic converter. Furthermore, PM accumulates in the catalyst device in a stepwise manner. Therefore, the processes from step ST5 to step ST6 are executed at least once before the processes from step ST3 to step ST4. As a result, the screens shown in Figures 5 and 6 are displayed on the meter panel 18 at least once before the screens shown in Figures 3 and 4.

[0039] In step ST7, the control unit 21 determines whether the driver has selected self-driving maintenance. The PM removal process warning notification screen 33 in Figure 5 displays a dealer processing button 34 and a self-driving processing button 35. The driver operates either button 34 or 35. If the self-driving processing button 35 is operated, the control unit 21 determines that the driver has selected self-driving maintenance and proceeds to step ST8. On the other hand, if the dealer processing button 34 is operated, the control unit 21 proceeds to step ST4. The control unit 21 displays information about dealers that can replace the catalytic converter. In this case, the dealer's process is not to replace the catalytic converter, but to burn off the PM accumulated in the catalytic converter. The dealer can effectively burn off the PM accumulated in the catalytic converter and refresh the catalytic converter through a special process tailored to the vehicle 1. Alternatively, the dealer can burn off the PM accumulated in the catalytic converter by driving the vehicle for a predetermined period.

[0040] In step ST8, the control unit 21 sets a removal flag 26 in the memory 20. The removal flag 26 in memory 20 may be the reset initial value. The removal flag 26 is used in the output control described later to switch between performance-prioritizing output control, which allows the normal performance of the engine 3 to be utilized, and removal-prioritizing output control, which prioritizes removal. When the removal flag 26 is set, the control unit 21 prioritizes removal-prioritizing output control over normal output control. When the removal flag 26 is reset, the control unit 21 executes normal output control and does not execute removal-prioritizing output control. Furthermore, by using such a removal flag 26, the control unit 21 does not need to start output control for removal when it determines that the catalytic converter requires self-propelled maintenance. The driving environment of the vehicle at the time the control unit 21 determines that the catalytic converter requires self-propelled maintenance is not necessarily suitable for output control for removal. For example, when the vehicle is parked or stuck in traffic, it is difficult for the vehicle 1 to continuously control the engine 3 to a lean state in order to obtain a high exhaust temperature that can burn off the PM. By using the removal flag 26, the control unit 21 can execute output control for the self-propelled maintenance process in a driving environment suitable for the self-propelled maintenance of the catalytic converter. Thus, in the first display processing of step ST6, if the control unit 21 selects an action to be improved by the driver's own actions while driving, it will execute output control for removal to improve the accumulation state of exhaust gases in the catalytic converter. Furthermore, the first screen from step ST6 will be displayed on the meter panel 18 at least once before the second screen from step ST3 is displayed.

[0041] In step ST9, the control unit 21 guides the vehicle along a route that allows for maintenance of the catalytic converter while it is in motion. For example, the control unit 21 may use the map data 27 stored in the memory 20 to search for a road section, such as a highway, that is suitable for performing output control for processing near the current position of the GNSS receiver 16, and then search for a route to that road section and display it on the meter panel 18. The road section searched here should be a distance that allows for the driving speed and distance required to burn out the PM. Subsequently, the control unit 21 terminates this control. The control unit 21 may terminate this control after processing in step ST8 without executing step ST9. In this case, the control unit 21 will prioritize output control for removal in subsequent runs based on the removal flag 26 already set in memory 20. Furthermore, if the route being searched before processing step ST9 includes an expressway, the control unit 21 may display that route on the meter panel 18 as is.

[0042] In this way, the control unit 21 separately determines, based on the detection results of the differential pressure sensors 10 to 12, whether the problem can be improved by the driver's actions while driving, and whether it cannot be improved by the driver's actions while driving. If the problem can be improved by the driver's actions while driving, the control unit 21 displays on the meter panel 18 that the problem can be improved by the driver's actions while driving through the first display process in step ST6. The meter panel 18 also displays that processing is required as an indication of the accumulation state of exhaust gases in the catalytic converter. Here, the fact that the problem can be improved by the driver's actions while driving is displayed on the meter panel 18 as one of several options that the driver can select, in addition to processing by a maintenance company that does not perform the work themselves. Furthermore, if the problem cannot be resolved by the driver's actions while driving, the control unit 21 displays on the meter panel 18, through the second display process in step ST3, that replacement by a dealer (a service provider) is required. If exhaust gas components that can be removed by self-propulsion have accumulated in the catalyst device, the control unit 21 can determine this state based on the detection results of the differential pressure sensors 10 to 12 and propose to the driver that the exhaust gas components be removed by self-propulsion. Furthermore, if the driver chooses to remove exhaust contaminants by driving, the control unit 21 sets a removal flag 26, which is recorded in the memory 20, in order to execute output control for processing to remove exhaust contaminants during subsequent driving.

[0043] Figure 7 is a flowchart of the output control that can handle the self-propelled removal process, performed by the control unit 21 in Figure 1. When the automobile 1 is in motion, the control unit 21 repeatedly executes the output control shown in Figure 7.

[0044] In step ST10, the control unit 21 determines whether or not the vehicle 1 is in motion. This determination of whether or not the vehicle 1 is in motion may include not only when the vehicle 1 is actually moving, but also when the vehicle 1 is parked or stopped for driving. The control unit 21 may determine whether or not the vehicle 1 is in motion based on, for example, whether the engine 3 is running, or whether an ignition switch (not shown) for operating the engine 3 is turned ON. If the vehicle 1 is not in motion, the control unit 21 may terminate this control without performing any specific output control. If the vehicle 1 is in motion, the control unit 21 proceeds to step ST11. Furthermore, the control unit 21 may start the output control shown in Figure 7 when the ignition switch is operated to the ON position. In this case, it is desirable for the control unit 21 to repeatedly execute the output control shown in Figure 7 until the ignition switch is operated to the OFF position. This ensures that the control unit 21 always executes the output control shown in Figure 7 only when the vehicle 1 is in motion.

[0045] In step ST11, the control unit 21 retrieves the value of the removal flag 26 stored in the memory 20 and determines whether the removal flag 26 is set or not. If the removal flag 26 is set, the control unit 21 proceeds to step ST13 in order to prioritize output control for processing to remove PM and other particles while driving. If the removal flag 26 has been reset and is not set, the control unit 21 proceeds to step ST12 for normal output control.

[0046] In step ST12, the control unit 21 performs normal output control. Here, normal output control may involve, for example, supplying a rich supply of gasoline to the engine 3 of automobile 1 to maximize the driving performance of automobile 1, while simultaneously using lean combustion for engine 3 when reducing gasoline consumption would not significantly affect driving performance. In contrast, the output control for processing keeps engine 3 running in a lean combustion state, except in emergencies. In lean combustion, the exhaust temperature of engine 3 rises compared to rich combustion, making it easier to burn off PM and other particles accumulated in the catalytic converter. For example, when driving with significant acceleration, such as when starting from a stop at a traffic light, lean combustion of engine 3 will dull the acceleration of vehicle 1. Therefore, when maintenance of the catalytic converter is not required, it is desirable for the control unit 21 to perform normal output control. Thus, in normal output control, the control unit 21 prioritizes a rich fuel supply to the engine 3 over a lean fuel supply in order to enable the engine 3 to perform to its full potential. Subsequently, the control unit 21 terminates this control.

[0047] In step ST13, the control unit 21 starts output control for removal. In the output control for removal, the control unit 21 prioritizes a lean state over a rich state for, for example, the supply of gasoline to the engine 3. When the gasoline supplied to the engine 3 of the automobile 1 is in a lean state, the exhaust temperature of the engine 3 increases. By being continuously or intermittently exposed to the high-temperature exhaust, PM and sulfur compounds accumulated in the catalytic converter can be burned off and removed from the catalytic converter. Furthermore, the control unit 21 may, if necessary, allow the engine 3 to burn in a rich state during the output control for removal. The control unit 21 may, in the output control for removal, prioritize a lean state over a rich state for the supply of gasoline to the engine 3.

[0048] In step ST14, the control unit 21 acquires information about the vehicle's surroundings in order to determine whether the current driving environment is suitable for output control for removal. The vehicle 1 is equipped with an external camera 13 and a LiDAR 14. The control unit 21 may acquire captured images and spatial information about the current surroundings from these external sensors 13 and 14. Based on the information acquired from the external sensors 13 and 14, the control unit 21 may acquire information about other vehicles around the vehicle, such as preceding vehicles and following vehicles, and information about the type of road the vehicle is traveling on, such as highways and general roads. The control unit 21 may also acquire information about signs installed on the road, such as the lighting status of traffic lights and stop lines, based on the information acquired from the external sensors 13 and 14.

[0049] In step ST15, the control unit 21 determines the current driving environment based on the acquired information about the vehicle's surroundings. For example, the control unit 21 may determine whether or not the automobile 1 is traveling at a high speed on an uncongested highway. For example, the control unit 21 may determine whether or not the automobile 1 is about to stop and start from a stop at a traffic light on a public road.

[0050] In step ST16, the control unit 21 determines whether the current driving environment is suitable for executing output control for processing. For example, the control unit 21 may determine that it can perform output control for processing if it determines that the current driving environment is such that the vehicle 1 is traveling at a high speed on an uncongested highway. For example, if the current driving environment is such that car 1 is traveling on a highway but is stopped at a low speed or in a traffic jam, the control unit 21 may determine that the current driving environment is such that output control for processing cannot be performed. For example, if car 1 is about to stop and start from a stop at a traffic light on a public road, the control unit 21 may determine that the current driving environment is suitable for executing output control for processing. For example, if car 1 is stopped on a public road at a low speed or in a traffic jam, the control unit 21 may determine that the current driving environment is not suitable for performing output control for processing. The decision in step ST15 will be explained in detail in Figure 9, which will be discussed later. As a result, the control unit 21 determines, based on the detection results of the external sensors around the vehicle 1, whether or not the driving environment is suitable for executing output control for removal. Then, if the current driving environment allows for the execution of output control for processing, the control unit 21 proceeds to step ST17. If the current driving environment is not suitable for executing output control for processing, the control unit 21 proceeds to step ST12. In this case, the control unit 21 will execute normal output control despite the removal flag 26 being set. The control unit 21 will not execute output control for processing that is suitable for removing PM and sulfur compounds from the catalyst. The control unit 21 will stop executing output control for processing until the driving environment becomes suitable for executing output control for processing.

[0051] In step ST17, the control unit 21 performs output control for processing. The control unit 21 performs output control prioritizing lean combustion. Thus, the control unit 21 performs output control for removal to improve the accumulation state of exhaust gas components in the catalytic converter only when it determines that the driving environment is suitable for performing output control for removal while the automobile 1 is in motion. This makes it easier to remove PM and sulfur compounds from the catalytic device.

[0052] In step ST18, the control unit 21 obtains detection results from the differential pressure sensors 10 to 12 during the execution of output control for processing.

[0053] In step ST19, the control unit 21 displays the detected results of the output control for processing that have been acquired on the meter panel 18. This allows the driver to easily visually confirm that the output control for processing is being executed while driving, and also the changes in the accumulation state of the catalyst due to that processing. Figure 8 shows an example of the PM accumulation status display screen 37 displayed on the meter panel 18 in Figure 1 during the process shown in Figure 7. The control unit 21 may display the PM accumulation status display screen 37 on the meter panel 18 during output control for processing. The PM accumulation status display screen 37 in Figure 8 displays the accumulation status of the catalyst device during processing using a level meter. Figure 8 shows an example of a state where approximately half of the catalyst device's capacity of PM has accumulated. In this manner, when the control unit 21 performs output control for removal to improve the accumulation of exhaust gases in the catalytic converter, it displays the accumulation status of exhaust gases in the catalytic converter on the meter panel 18, based on the detection results of the differential pressure sensors 10 to 12. The driver of the automobile 1 can understand the progress of the catalytic converter's improvement in detail. Furthermore, based on the display, the driver can understand that the system has switched from normal output control to output control for removal to improve the accumulation of exhaust gases in the catalytic converter, and also understand the timing of the return to the original normal output control. The driver can understand the driving status of the automobile 1.

[0054] In step ST20, the control unit 21, while performing output control for processing, instructs the driver to perform variable operation of the accelerator as needed. By operating the accelerator to open and close, large pressure changes are more likely to occur in the exhaust. This can make it easier to remove PM accumulated from the catalytic converter. Step ST20 is not a necessary process when performing output control for processing.

[0055] In step ST21, the control unit 21 determines whether or not to terminate the output control for processing. If the PM accumulated in the catalytic device is almost completely removed from the catalytic device through processing, there is no need to perform further output control for processing. Furthermore, even if the output control for processing is run for a while, the accumulation of PM in the catalyst may not show significant improvement. In this case, continuing to run the output control for processing further is unlikely to yield a satisfactory removal effect. If the PM accumulated in the catalyst completely solidifies, it becomes difficult to remove. Then, when the control unit 21 determines that it has finished output control for processing, it proceeds to step ST22. If the control unit 21 determines that it will continue without terminating the output control for processing, it terminates this control without proceeding to step ST22.

[0056] In step ST22, the control unit 21 resets the removal flag 26 in the memory 20 to terminate the output control for processing. After that, the control unit 21 terminates this control.

[0057] In this way, the control unit 21 can control the start or continuation of the execution of output control for processing based on the setting of the removal flag 26 in the memory 20. Furthermore, the control unit 21 can execute output control for processing when the current driving environment is suitable for executing output control for processing. Furthermore, the control unit 21 can display the status of PM removal from the catalyst device on a display device such as the meter panel 18 while it is performing output control for processing.

[0058] Figure 9 is an example of a detailed flowchart for determining the driving environment of vehicle 1 in the output control shown in Figure 7. The control unit 21 may perform the driving environment determination shown in Figure 9 in step ST15 of Figure 7. Based on the driving environment determination shown in Figure 9, the control unit 21 will determine whether step ST39 can be executed or step ST40 cannot be executed. Then, in step ST16 of Figure 7, the control unit 21 may determine, based on the driving environment determination result of Figure 9, whether or not the current driving environment is suitable for executing output control for processing.

[0059] In step ST31, the control unit 21 determines whether or not the vehicle 1 is traveling on a highway. In this case, the control unit 21 may make the determination based on the detection information from the external sensors 13 and 14, or based on the latest position and map data 27 generated by the GNSS receiver 16. The roads on which the vehicle 1 generally travels can be classified into highways and general roads. Highways are designed to allow the vehicle 1 to travel at higher speeds than general roads. When the vehicle 1 is traveling at high speed, the engine 3 tends to maintain a higher rotational speed than when traveling at low speed. When the engine 3 is in a lean state during such driving, the exhaust temperature tends to be high and stable. Exhaust components such as PM accumulated in the catalytic converter are continuously burned at high temperatures and are easily detached from the catalytic converter and discharged. If the control unit 21 determines that vehicle 1 is traveling on a highway, it proceeds to step ST32. If the control unit 21 does not determine that vehicle 1 is traveling on a highway, it proceeds to step ST36.

[0060] In step ST32, the control unit 21 determines that the automobile 1 is traveling on a highway.

[0061] In step ST33, the control unit 21 determines whether the driving state of the vehicle 1 is stable at high speed. When driving on a straight highway, the vehicle 1 is likely to be stable at high speed. The speed considered to be high speed may be, for example, 60 km / h or 70 km / h. Stabilization at high speed can be defined as, for example, the period until exhaust contaminants such as PM accumulated in the catalytic converter begin to burn off, even partially. If the vehicle is in a stable, high-speed driving state, the control unit 21 proceeds to step ST34. If the vehicle is not in a high-speed, stable driving state, the control unit 21 proceeds to step ST40.

[0062] In step ST34, the control unit 21 determines whether the driving state of the vehicle 1 is such that the distance between it and the preceding vehicle is equal to or greater than a threshold (distance threshold). Changing the output control of the vehicle 1 from normal to processing mode may degrade the performance of the vehicle 1. For this reason, when starting to drive with processing output control, it is desirable to ensure a sufficient distance between the vehicle and the preceding vehicle. The distance threshold used here may be, for example, the distance that is recommended to be maintained depending on the vehicle speed. Then, if the distance between the vehicle and the preceding vehicle is greater than or equal to the distance threshold, the control unit 21 proceeds to step ST35. If the distance to the preceding vehicle is not equal to or greater than the distance threshold, the control unit 21 proceeds to step ST40.

[0063] In step ST35, the control unit 21 determines whether the driving state of the vehicle 1 is such that the distance between it and the following vehicle is equal to or greater than a threshold (distance threshold). When vehicle 1 starts driving with processing output control, it may exhibit different behavior than when it was driving with normal output control up to that point. The driver of the following vehicle needs to deal with this change. For this reason, when starting to drive with processing output control, it is desirable to maintain a sufficient distance between the vehicle and the following vehicle. The distance threshold used here may be, for example, the distance that is recommended to be maintained depending on the vehicle speed. Then, if the distance between the following vehicle and the vehicle below is greater than or equal to the following vehicle threshold, the control unit 21 proceeds to step ST39. If the distance between the following vehicle and the vehicle below is not equal to or greater than the following vehicle threshold, the control unit 21 proceeds to step ST40.

[0064] In step ST36, the control unit 21 determines that the vehicle 1 is traveling on a regular road and not on an expressway. Driving on ordinary roads is more prone to disturbances and less stable than driving on expressways. However, there are drivers who rarely drive on highways. Therefore, in this embodiment, even when the vehicle 1 is driving on ordinary roads, the output control for processing can be executed intermittently. As a result, it is expected that the effect of removing exhaust contaminants such as PM from the catalytic converter will be higher compared to when the output control for processing is performed only on highways.

[0065] In step ST37, the control unit 21 determines whether the vehicle is starting from a stop. When the vehicle 1 is in motion, it stops at a stop signal or stop line, and then starts moving again to continue driving. If output control for processing is used when starting from a stop, the vehicle 1 will accelerate slowly. The driver may further press the accelerator to obtain the desired acceleration. During the period until the speed limit is reached, the exhaust temperature of the engine 3 can be expected to rise. If the vehicle is starting from a standstill, the control unit 21 proceeds to step ST38. If the vehicle is not starting from a standstill, the control unit 21 proceeds to step ST40.

[0066] In step ST38, the control unit 21 checks the safety of the area behind the vehicle 1 as part of the vehicle's driving status. If a following vehicle starts moving while maintaining a close gap, changing the output control of vehicle 1 from normal to processing mode may result in a situation caused by a decrease in the vehicle 1's driving performance. If the area behind the vehicle is safe, the control unit 21 proceeds to step ST39. If the area behind the vehicle is unsafe, the control unit 21 proceeds to step ST40. Furthermore, the control unit 21 may check for safety not only behind the vehicle but also in front of the vehicle as part of the vehicle's driving status.

[0067] In step ST39, the control unit 21 determines that the current driving environment of the vehicle is feasible. After that, the control unit 21 terminates this control.

[0068] In step ST40, the control unit 21 determines that the current driving environment of the vehicle is unsuitable. Subsequently, the control unit 21 terminates this control.

[0069] As a result, when the control unit 21 determines that the vehicle 1 is traveling in a predetermined driving environment on a highway in which processing can be performed, it executes output control for processing, putting the engine 3 into a lean combustion state and increasing its exhaust temperature while traveling at high speed. In this case, it can be expected that the output control for processing will be executed continuously and effectively on the highway. Furthermore, if the control unit 21 determines that the vehicle 1 is traveling in a predetermined driving environment on a public road in which processing can be performed, it will execute output control for public roads when starting from a stop, putting the engine 3 into a lean combustion state and increasing its exhaust temperature. In this case, it can be expected that the output control for processing may be executed intermittently.

[0070] Figure 10 is an example of a detailed flowchart for determining the end of PM removal control in the output control shown in Figure 7. Figure 10 is a flowchart for determining the end of removal control in an example suitable for removing PM accumulated in a catalytic converter while driving on a highway. In step ST21 of Figure 7, the control unit 21 may perform the termination determination shown in Figure 10.

[0071] In step ST51, the control unit 21 obtains the latest detected speed from the vehicle speed sensor and determines whether the vehicle's current speed is maintained at 60 km / h or higher. The threshold speed used to determine speed could also be, for example, 70 km / h. If the vehicle's current speed is maintained at 60 km / h or higher, the control unit 21 proceeds to step ST52. If the vehicle's current speed cannot be maintained at 60 km / h or higher, the control unit 21 proceeds to step ST53.

[0072] In step ST52, the control unit 21 determines whether 30 minutes have elapsed since the start of output control for processing. The control unit 21 may determine whether 30 minutes have elapsed by obtaining the current information of the measurement period instructed to the timer 17 when the output control for processing was started. The threshold period used to determine the duration could also be, for example, 40 minutes. If 30 minutes have elapsed since the start of processing, the control unit 21 proceeds to step ST54. If 30 minutes have not elapsed since the start of processing, the control unit 21 proceeds to step ST53.

[0073] In step ST53, the control unit 21 determines that the PM removal control has not finished and is therefore incomplete. Subsequently, the control unit 21 terminates this control. In this case, the control unit 21 determines in step ST21 of Figure 7 that it will not terminate the removal control and continues the output control for removal.

[0074] In step ST54, the control unit 21 acquires the detection results from the differential pressure sensors 10 to 12.

[0075] In step ST55, the control unit 21 determines whether the detected values ​​of the differential pressure sensors 10 to 12 have improved to below the removal threshold. Here, the removal threshold should basically be a value smaller than the warning threshold. Preferably, the removal threshold should be the detected values ​​of the differential pressure sensors 10 to 12 when there is almost no accumulation of exhaust gas in the catalytic converter. If the detected values ​​from the differential pressure sensors 10 to 12 are below the rejection threshold, the control unit 21 proceeds to step ST56. If the detected values ​​from the differential pressure sensors 10 to 12 are not below the rejection threshold, the control unit 21 proceeds to step ST57.

[0076] In step ST56, the control unit 21 determines that the exhaust residue has been effectively removed by the self-propelled PM removal control and confirms that the process has been successfully completed. Furthermore, the control unit 21 may display a successful completion message on the meter panel 18. After that, the control unit 21 terminates this control. In this case, the control unit 21 determines that it will terminate the removal control during the process of step ST21 in Figure 7, and will not perform the output control for removal thereafter.

[0077] Figure 11 shows an example of a success notification screen 38 for the PM removal process displayed on the meter panel 18 in Figure 1 during the process shown in Figure 10. The PM removal process success notification screen 38 in Figure 11 displays a message indicating that the exhaust residue has been successfully removed by the self-propelled PM removal control. The driver can then recognize the processing result of the self-propelled PM removal control.

[0078] In step ST57, the control unit 21 determines that it was unable to effectively remove exhaust residue through self-propelled PM removal control, and thus confirms that the process has ended unsuccessfully. Furthermore, the control unit 21 may display an unsuccessful termination on the meter panel 18. Furthermore, the control unit 21 may display dealer information on the meter panel 18. After that, the control unit 21 terminates this control. In this case, the control unit 21 determines that it will terminate the removal control during the process of step ST21 in Figure 7, and will not perform the output control for removal thereafter.

[0079] Figure 12 shows an example of a notification screen 39 indicating the failure of the PM removal process, which is displayed on the meter panel 18 in Figure 1 during the process shown in Figure 10. The PM removal process failure notification screen 39 in Figure 12 displays a message indicating that the PM removal control by self-propulsion failed to effectively remove exhaust residues. The driver can recognize that the PM removal control by self-propulsion was unable to sufficiently remove exhaust components such as PM accumulated in the catalytic converter. Furthermore, the PM removal process failure notification screen 39 in Figure 12 displays a driver-operable dealer guidance button 40. This allows the driver to recognize that further processing of the catalyst device is required.

[0080] As shown in Figure 10, the termination determination for PM removal control determines whether the time during which the engine 3 is running in a lean combustion state while the vehicle 1's speed is above the speed threshold is at least above the time threshold. In this case, the output control for removal, which is necessary to improve the accumulation of exhaust gases in the catalytic converter, will be executed continuously or intermittently until the termination determination condition is met. Furthermore, after performing output control for removal at least once, the control unit 21 determines whether the accumulation of exhaust contaminants in the catalytic converter has improved based on the detection results of the differential pressure sensors 10 to 12. If the accumulation of exhaust contaminants in the catalytic converter has not improved, the control unit 21 stops the output control for removal to improve the accumulation of exhaust contaminants in the catalytic converter and displays a third screen on the meter panel 18, which includes a notification of the actions taken by the dealer, which is the maintenance provider. The third screen does not include actions taken by the driver while driving.

[0081] Figure 13 is an explanatory diagram illustrating an example of the relationship between the PM accumulation rate of the PM catalyst device and the pressure difference detected by differential pressure sensors 10-12. The three-way catalytic converter 5 functions as a PM catalytic converter. The horizontal axis of Figure 13 represents the PM accumulation rate in the PM catalyst device. The vertical axis of Figure 13 represents the pressure difference detected by differential pressure sensors 10-12. Figure 13 shows the characteristic curve 70 of the PM catalyst device. This characteristic curve 70 is just one example. The pressure difference detected by differential pressure sensors 10-12 increases as the amount of PM accumulated in the PM catalyst increases and the accumulation ratio increases. When the accumulation ratio in the PM catalyst becomes approximately 1, the PM catalyst needs to be replaced. In a PM catalyst device with these characteristics, as shown in the figure, the exchange threshold, warning threshold, and removal threshold can be set. The replacement threshold should be slightly smaller than the pressure difference that occurs when the PM catalyst is replaced. The warning threshold should ideally be lower than the replacement threshold, but preferably lower than the pressure difference during a professional removal process at a dealership. This allows dealerships to remove PM from the PM catalyst system through a professional removal process immediately after a warning is issued, without having to replace the PM catalyst system. Alternatively, the warning threshold should be higher than the pressure difference in a new PM catalyst system that has not accumulated any PM. The warning threshold can be set to any value between the pressure difference that the dealer can handle and the pressure difference of a new unit. Lowering the warning threshold tends to increase the frequency of warnings and self-drive processes, but it helps keep the PM catalyst unit in a relatively clean state. Increasing the warning threshold can reduce the frequency of warnings and self-drive processes. The removal threshold should be smaller than the warning threshold. Furthermore, the removal threshold should be larger than the pressure difference in a new PM catalyst device where no PM has accumulated. Furthermore, by setting a low removal threshold, the PM catalyst system can recover to a relatively clean state. This also allows for a longer period before further processing is required after recovery. Increasing the removal threshold is expected to increase the number of successful completions during self-propelled processing.

[0082] As described above, in this embodiment, the accumulation state of exhaust contaminants in the catalytic converter used in the exhaust system 4 of the engine 3 of the automobile 1 is detected by differential pressure sensors 10 to 12. The control unit 21 then determines the accumulation state of exhaust contaminants in the catalytic converter according to the detection results of the differential pressure sensors 10 to 12. This makes it possible to manage the accumulation state of exhaust contaminants in the catalytic converter of the exhaust system 4 of the automobile 1 in this embodiment. In particular, in this embodiment, depending on the determination result of the exhaust gas content accumulation state in the catalytic converter, output control for removal is performed during the driving of the vehicle 1 after the determination has been made to improve the exhaust gas content accumulation state in the catalytic converter. As a result, the exhaust gas content accumulation state in the catalytic converter of the vehicle 1 can be improved as the vehicle 1 is driven. Exhaust gas content such as nitrogen oxides, soot, or sulfur compounds contained in the exhaust becomes less likely to accumulate in large quantities in the catalytic converter of the vehicle 1. Direct injection gasoline engines capable of lean combustion tend to have an increase in these exhaust gas content compared to engines 3 that do not perform lean combustion or engines 3 that do not directly inject gasoline. By using this embodiment, exhaust gas content accumulation becomes less likely even in catalytic converters used in the exhaust system 4 of a direct injection gasoline engine capable of lean combustion. Furthermore, this embodiment includes an external sensor that detects the surroundings of the automobile 1. The control unit 21 also determines whether the driving environment is suitable for executing output control for removal based on the detection results of the external sensor's detection of the surroundings of the automobile 1. The control unit 21 then executes output control for removal to improve the accumulation state of exhaust contaminants in the catalytic converter only when it determines that the driving environment is suitable for executing output control for removal. As a result, the control unit 21 of the automobile 1 executes output control for removal, which is performed while the automobile 1 is in motion, only when it determines that the driving environment is suitable for executing output control for removal. The driver does not need to determine for themselves whether the current driving environment is suitable for executing output control for removal. In addition, output control for removal can only be executed when the driving environment is safe. The burden on the driver is reduced.

[0083] In this embodiment, the control unit 21 determines whether or not the automobile 1 is traveling on a highway. If the automobile 1 is traveling on a highway, the control unit 21 continuously performs output control for highways, which puts the engine 3 into a lean combustion state and increases its exhaust temperature while the automobile is traveling at high speeds. As a result, in this embodiment, while the automobile 1 is traveling on a highway, output control for removal appropriate to the driving environment is performed, and nitrogen oxides, soot, or sulfur compounds accumulated in the catalytic converter can be efficiently removed from the catalytic converter. Furthermore, the control unit 21 determines whether or not the vehicle 1 is traveling on a public road. If the vehicle 1 is traveling on a public road, the control unit 21 repeatedly performs output control for public roads, which puts the engine 3 into a lean combustion state and increases its exhaust temperature when starting from a stop. In this embodiment, by performing output control for removal that can be executed under the driving environment while traveling on a public road, nitrogen oxides, soot, or sulfur compounds accumulated in the catalytic converter can be removed from the catalytic converter.

[0084] [Second Embodiment] Next, a control device for the exhaust system catalyst of an automobile 1 according to a second embodiment of the present invention will be described. The following description will mainly focus on the differences from the embodiments described above. The same configurations and processes as those in the embodiments described above will not be described. The above-described embodiment is an example of removing mainly PM from exhaust gases that may accumulate in the catalytic converter. In this embodiment, we will describe an example of removing mainly sulfur compounds from exhaust gases that may accumulate in the catalytic converter. In this case, the control by the control unit 21 may be basically the same as in the embodiment described above. However, it is desirable to modify at least a portion of the display on the meter panel 18 and the termination determination of the removal control from the embodiments described above. Furthermore, if only sulfur compounds are to be removed, the treatment in step ST21 of Figure 7 may be unnecessary.

[0085] Figure 14 shows an example of a notification screen 50 for the replacement of a catalyst device for sulfur compounds, displayed on the meter panel 18 in Figure 1, as a result of the processing shown in Figure 2 in the second embodiment of the present invention. In step ST3 of Figure 2, the control unit 21 generates a "Dealer Replacement Required" display screen 50 informing the user that the catalyst device for sulfur compounds shown in Figure 14 needs to be replaced, and displays it on the meter panel 18. Furthermore, the sulfur oxide catalyst replacement notification screen 50 in Figure 3 displays a message notifying the driver that the sulfur compound catalyst needs to be replaced, along with a driver-operable dealer guidance button 51. This allows the driver to recognize that the sulfur oxide catalyst needs to be replaced while driving or while riding in the vehicle 1.

[0086] Figure 15 shows an example of a warning notification screen 53 for sulfur compound removal processing displayed on the meter panel 18 in Figure 1, based on the processing shown in Figure 2 in the second embodiment of the present invention. In step ST6 of Figure 2, the control unit 21 generates the sulfur compound removal process warning notification screen 53 shown in Figure 15 and displays it on the meter panel 18. Furthermore, the warning notification screen 53 for the sulfur compound removal process in Figure 15 displays a message warning about the removal process for sulfur oxides, along with a driver-operated dealer processing button 54 and a self-driving processing button 55 that allows the driver to perform the process while driving the vehicle. This allows the driver to recognize that maintenance is required to remove sulfur oxides from the catalyst device for sulfur oxides.

[0087] Figure 16 is an example of a detailed flowchart for determining the termination of sulfur compound removal control in the second embodiment of the present invention. Figure 16 is a flowchart for determining the end of removal control in an example suitable for removing sulfur compounds accumulated in a catalytic converter while driving on a highway. In step ST21 of Figure 7, the control unit 21 may perform the termination determination shown in Figure 16, etc.

[0088] In step ST61, the control unit 21 obtains the latest detected speed from the vehicle speed sensor and determines whether the vehicle's current speed is maintained at 70 km / h or higher. If the vehicle's current speed is maintained at 70 km / h or higher, the control unit 21 proceeds to step ST62. If the vehicle's current speed cannot be maintained at 70 km / h or higher, the control unit 21 proceeds to step ST63.

[0089] In step ST62, the control unit 21 obtains the current measurement period from, for example, the timer 17 and determines whether 5 minutes have elapsed since the start of output control for processing. If the processing period has elapsed 5 minutes, the control unit 21 proceeds to step ST64. If the processing period has not elapsed 5 minutes, the control unit 21 proceeds to step ST63.

[0090] In step ST63, the control unit 21 determines that the sulfur compound removal control is not yet complete and confirms that it is incomplete. Subsequently, the control unit 21 terminates this control. In this case, the control unit 21 determines in step ST21 of Figure 7 that it will not terminate the removal control and continues the output control for removal.

[0091] In step ST64, the control unit 21 acquires the detection results from the differential pressure sensors 10 to 12.

[0092] In step ST65, the control unit 21 determines whether the detected values ​​of the differential pressure sensors 10 to 12 have improved to below the removal threshold. Here, the removal threshold should basically be a value smaller than the warning threshold. Preferably, the removal threshold should be the detected values ​​of the differential pressure sensors 10 to 12 when there is almost no accumulation of exhaust gas in the catalytic converter. If the detected values ​​from the differential pressure sensors 10 to 12 are below the rejection threshold, the control unit 21 proceeds to step ST66. If the detected values ​​from the differential pressure sensors 10 to 12 are not below the rejection threshold, the control unit 21 proceeds to step ST67.

[0093] In step ST66, the control unit 21 determines that the exhaust residue has been effectively removed by the self-propelled sulfur compound removal control, and confirms that the process has been successfully completed. Furthermore, the control unit 21 may display a successful completion message on the meter panel 18. After that, the control unit 21 terminates this control. In this case, the control unit 21 determines that it will terminate the removal control during the process of step ST21 in Figure 7, and will not perform the output control for removal thereafter.

[0094] Figure 17 shows an example of a success notification screen 58 for the sulfur compound removal process displayed on the meter panel 18 in Figure 1, during the process shown in Figure 16. The success notification screen 58 of the sulfur compound removal process in Figure 11 displays a message indicating that the exhaust residue was successfully removed by the self-propelled sulfur compound removal control. The driver can recognize the processing result of the self-propelled PM removal control.

[0095] In step ST67, the control unit 21 determines that it was unable to effectively remove exhaust residue through self-propelled sulfur compound removal control, and thus confirms that the process has ended unsuccessfully. Furthermore, the control unit 21 may display an unsuccessful termination on the meter panel 18. Furthermore, the control unit 21 may display dealer information on the meter panel 18. After that, the control unit 21 terminates this control. In this case, the control unit 21 determines that it will terminate the removal control during the process of step ST21 in Figure 7, and will not perform the output control for removal thereafter.

[0096] Figure 18 shows an example of a notification screen 59 indicating the failure of the sulfur compound removal process, which is displayed on the meter panel 18 in Figure 1 during the process shown in Figure 16. The unsuccessful sulfur compound removal process notification screen 59 in Figure 18 displays a message indicating that the self-propelled sulfur compound removal control failed to effectively remove exhaust residues. The driver can recognize that the self-propelled sulfur compound removal control was unable to sufficiently remove exhaust components such as sulfur compounds accumulated in the catalytic converter. Furthermore, the unsuccessful sulfur compound removal process notification screen 59 in Figure 18 displays a driver-operable dealer guidance button 60. This allows the driver to recognize that further processing of the catalyst device is required.

[0097] As shown in Figure 16, the termination determination for sulfur compound removal control determines whether the time during which the engine 3 is running in a lean combustion state while the vehicle 1's speed is above the speed threshold is at least above the time threshold. In this case, the output control for removal, which is necessary to improve the accumulation of exhaust gases in the catalytic converter, will be executed continuously or intermittently until the termination determination condition is met. Furthermore, after performing output control for removal at least once, the control unit 21 determines whether the accumulation of exhaust contaminants in the catalytic converter has improved based on the detection results of the differential pressure sensors 10 to 12. If the accumulation of exhaust contaminants in the catalytic converter has not improved, the control unit 21 stops the output control for removal to improve the accumulation of exhaust contaminants in the catalytic converter and displays a screen (third screen) 59 on the meter panel 18 that notifies the dealer, who is a maintenance provider, of the action taken. The third screen does not include a button prompting the driver to take action while driving.

[0098] As described above, in this embodiment, similar to the embodiment described above, it becomes possible to determine the state of exhaust gas accumulation in the catalytic converter used in the exhaust system 4 of the engine 3 of the automobile 1 based on the detection results of differential pressure sensors 10 to 12, and to manage the state of exhaust gas accumulation. Furthermore, in automobile 1 to which such an embodiment is applied, even a driver who is unaware of the need to remove exhaust contaminants accumulated in the catalytic converter can maintain the catalytic converter in a clean state for a long period of time. Furthermore, the driver can maintain and use the catalytic converter in a clean state for a longer period without having to determine the driving conditions themselves to perform a drive to remove exhaust contaminants accumulated in the catalytic converter. Moreover, during output control for processing, the driver can deepen their understanding of the catalyst's accumulation status and other information displayed on the meter panel 18, and thus become less likely to experience discomfort. Even if the driver is guided to a route they don't normally use, it is expected that they will be less likely to feel uncomfortable. Furthermore, it is expected that the driver will learn to drive according to the control of the control unit 21 on the route guided for processing. The burden on the driver can be reduced. In this embodiment, it is possible to effectively manage the catalytic converter used in the exhaust system 4 of the engine 3 of the automobile 1 while reducing the burden on the driver.

[0099] The embodiments described above are examples of preferred embodiments of the present invention, but the present invention is not limited thereto, and modifications can be made as appropriate without departing from the spirit of the invention.

[0100] The embodiments described above disclose output control for processing that is suitable for each type of exhaust gas content. The control unit 21 may perform output control for processing that integrates the embodiments described above. For example, if the engine 3 is operated in a lean state continuously for 30 minutes or more at a speed of 70 km / h or more, the exhaust temperature will be efficiently maintained at a high level during that time. In this case, it is thought that exhaust contaminants accumulated in each of the multiple catalytic converters provided in the automobile 1 can be efficiently removed. By the control unit 21 performing such output control for processing, multiple types of exhaust contaminants such as NOx, soot, and sulfur compounds can be removed from all of the multiple catalytic converters provided in the automobile 1.

[0101] The embodiments described above primarily assume a state in which the automobile 1 is driving according to the driver's operations. The control unit 21 of the automobile 1 may similarly perform output control for processing, whether it is assisting the driver's operation to control the driving of the automobile 1 or controlling the driving of the automobile 1 through automatic driving without driver operation. In the case of automated driving that includes these driver assistance features, the control unit 21 may replace the accelerator operation instruction process in step ST20 of Figure 7 with a process that notifies that the accelerator is being automatically and variably controlled.

[0102] For the sake of simplicity, the above-described embodiment illustrates an example in which the automobile 1 is equipped with one ECU, and this one ECU performs all the control of the control unit 21 described above. However, modern automobiles typically have multiple control units (ECUs). These multiple ECUs are connected to each other via an in-vehicle network such as CAN, enabling them to communicate with one another. These multiple ECUs in automobile 1 may cooperate to perform all of the above-mentioned controls. Furthermore, modern automobiles often have a communication control unit that communicates with an external base station or similar device. In this case, some of the above-mentioned controls may be performed by a control unit of the base station that can communicate with the communication control unit, and further by a server device that can communicate with the communication control unit of automobile 1 through the base station. Furthermore, when transmitting information from vehicle 1 to an external location in this manner, it is desirable that the information transmitted from vehicle 1 to the outside be processed in such a way that it is impossible to identify an individual contained in the information, even when based on or combined with other information. Additionally, it is desirable that information transmitted and received via communication be encrypted or encoded. [Explanation of Symbols]

[0103] 1...Automobile (vehicle), 2...Vehicle body, 3...Engine, 4...Exhaust system, 5...Three-way catalytic converter (PM catalytic converter), 6...First NO X Storage and reduction catalyst device, 7... Second NOX Storage and reduction catalyst device, 10...First differential pressure sensor, 11...Second differential pressure sensor, 12...Third differential pressure sensor, 13...External camera (external sensor), 14...Lidar (external sensor), 15...Speed ​​sensor, 16...GNSS receiver, 17...Timer, 18...Meter panel, 19...Speaker, 20...Memory, 21...Control unit, 26...Removal flag, 27...Map data, 30...Replacement notification screen, 31,40,51,60...Dealer guidance button, 32...Check lamp screen, 33...Warning notification screen, 34,54...Dealer processing button, 35,55...Self-driving processing button, 36...Warning lamp screen, 37...Display screen, 38,58...Success notification screen, 39,59...Failure notification screen, 50...Replacement notification screen, 53...Warning notification screen, 70...Characteristic curve

Claims

1. A catalytic converter used in the exhaust system of a vehicle engine, A differential pressure sensor detects the accumulation state of exhaust gas components in the catalytic converter based on the pressure difference between the inlet and outlet pressures of the catalytic converter. A control unit that performs output control for removal in order to improve the aforementioned accumulation state, An external sensor that detects the surroundings of the vehicle, It has, The control unit, Based on the detection result of the differential pressure sensor, it is determined whether or not exhaust gas components are accumulating in the catalyst device. Based on the detection results of the external sensor around the vehicle, it is determined whether the vehicle is traveling on a public road or highway where the output control for removal can be executed. If exhaust contaminants are accumulating in the catalytic converter and it is determined that the vehicle is traveling on the expressway, the engine is made lean during the vehicle's high-speed travel to increase the exhaust temperature and execute the expressway-specific output control for removal to improve the accumulation state. If exhaust contaminants have accumulated in the catalytic converter and it is determined that the vehicle is traveling on the public road, the engine is set to a lean state when the vehicle starts moving from a stop to increase the exhaust temperature, thereby executing the output control for removal on public roads to improve the accumulation state. A control device for the catalytic converter in a vehicle's exhaust system.

2. The catalytic converter removes nitrogen oxides, soot, or sulfur compounds from the exhaust of the engine. A control device for the exhaust system catalyst of a vehicle, as described in claim 1.

3. The control unit, The output control for removal is as follows: The process is carried out until the time during which the engine burns in a lean state while the vehicle is traveling at a speed threshold or higher is at least equal to or greater than a time threshold. A control device for the exhaust system catalyst of a vehicle, according to claim 1 or 2.

4. It has memory, The control unit, The result of determining the storage state using the detection result of the differential pressure sensor is recorded in the memory. When controlling the movement of the vehicle, the determination of whether or not to perform the output control for removal is made by referring to the determination result recorded in the memory. A control device for the exhaust system catalyst of a vehicle, as described in claim 3.

5. Having a display device, The control unit, When performing the output control for removal to improve the accumulation state, the accumulation state is displayed on the display device based on the detection result of the differential pressure sensor during the output control for removal. A control device for the exhaust system catalyst of a vehicle, as described in claim 4.

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