Control device of vehicle, control method of vehicle, and storage medium

Abstract

A control device of a vehicle, a control method of a vehicle, and a storage medium are provided. An air supply passage is connected to a portion of an exhaust passage that is upstream of a filter. An air supply process supplies air to the filter via the air supply passage by driving an air pump. An oxygen supply process supplies oxygen that has passed through a combustion chamber of an internal combustion engine to the filter via the exhaust passage. A reduction process makes an amount of air supplied per unit time in the air supply process while the oxygen supply process and the air supply process are simultaneously performed less than an amount of air supplied per unit time in the air supply process when the oxygen supply process and the air supply process are not simultaneously performed.

Description

Technical Field

[0001] This disclosure relates to a control device for controlling a vehicle equipped with an internal combustion engine, a vehicle control method, and a storage medium. Background Technology

[0002] Japanese Patent Application Publication No. 2010-013974 discloses an internal combustion engine equipped with an air supply device for introducing air into the exhaust passage. The air supply device includes an air supply passage connected to the exhaust passage and an air pump. The internal combustion engine disclosed in the above document supplies air into the exhaust passage via the air supply passage by driving the air pump. The air supply device promotes the combustion of accumulated particulate matter by supplying air to a filter installed in the exhaust passage.

[0003] Furthermore, Japanese Patent Application Publication No. 2021-060027 discloses a vehicle equipped with an internal combustion engine having multiple cylinders. This vehicle is equipped with an exhaust purification device for purifying the exhaust gas discharged from the multiple cylinders. The control device of the vehicle disclosed in this document performs a stop operation. The stop operation stops the fuel supply to one or more of the cylinders that are shut down, while simultaneously supplying fuel to the remaining cylinders.

[0004] Therefore, by performing a shutdown process, oxygen is supplied to the exhaust purification device through the shutdown cylinder where fuel supply is stopped. The oxidation reaction in the catalyst is promoted, thus promoting the combustion of particulate matter accumulated in the filter.

[0005] By treating the oxygen supply from the combustion chamber of the internal combustion engine to the exhaust passage, similar to stopping the process, it is also possible to promote the combustion of particulate matter accumulated in the filter.

[0006] Supplying oxygen to the filter can accelerate its regeneration by promoting the combustion of particulate matter. However, excessive oxygen supply can lead to overheating of the filter. Therefore, it is desirable to complete the filter regeneration process quickly while preventing overheating. Summary of the Invention

[0007] According to one aspect of this disclosure, a vehicle control device is provided. The vehicle to which the control device is applied includes an air supply passage and an air pump connected to an exhaust passage upstream of a filter. An internal combustion engine is equipped with an air supply device that introduces air into the exhaust passage via the air supply passage by driving the air pump. The control device performs: air supply processing, supplying air introduced into the exhaust passage via the air supply passage by driving the air pump to the filter; and oxygen supply processing, supplying oxygen that has passed through the combustion chamber of the internal combustion engine to the filter via the exhaust passage. The control device performs a reduction processing related to the amount of air supplied per unit time in the air supply processing. The reduction processing causes the amount of air supplied per unit time in the air supply processing when both the oxygen supply processing and the air supply processing are performed simultaneously to be less than the amount of air supplied per unit time in the air supply processing when neither the oxygen supply processing nor the air supply processing is performed simultaneously.

[0008] If the air supply process and the oxygen supply process are performed simultaneously, the insufficient oxygen supply that would be required if only one of the air supply process or the oxygen supply process were performed can be compensated by the other. Therefore, filter regeneration is completed quickly. However, if the air supply process and the oxygen supply process are performed simultaneously, the filter may overheat due to an excess of oxygen supplied to it. In contrast, the control device described above reduces the amount of oxygen supplied by the air supply device. Therefore, the control device can supply the "insufficient oxygen if only the oxygen supply process were performed" while suppressing the supply of excess oxygen. That is, this control device can prevent filter overheating while ensuring rapid filter regeneration.

[0009] In one embodiment of the vehicle control device, during the reduction process, the greater the accumulation of particulate matter in the filter at the start of the reduction process, the less air is supplied per unit time.

[0010] The greater the amount of particulate matter accumulated in the filter, the more likely it is to overheat due to oxygen supply. Based on the above configuration, by controlling the air supply in accordance with the ease of overheating, it is possible to suppress the overheating of the filter.

[0011] In one embodiment of the vehicle control device, when the oxygen supply process is not performed simultaneously with the air supply process, the air supply process involves driving the electrically powered air pump at a predetermined speed for a predetermined time. The reduction process involves lowering the speed of the air pump below the predetermined speed. Furthermore, in this control device, when the reduction process is performed during the air supply process, an extension process is performed to extend the time the air pump is driven.

[0012] Electric air pumps are difficult to operate continuously under high loads for extended periods. Therefore, the control device protects the air pump by limiting the operation at a predetermined speed to a predetermined time. When the speed is reduced in the reduction process, the load on the air pump decreases, thus extending the pump's operating time. Therefore, this control device, while performing the reduction process, also performs an extension process that extends the air pump's operating time. Thus, by extending the period of simultaneous air supply and oxygen supply operations while protecting the air pump, this control device enables rapid filter regeneration.

[0013] In one embodiment of the vehicle control device, the greater the amount of particulate matter accumulated in the filter at the start of the reduction process during the extended process, the longer the extension time for driving the air pump.

[0014] The greater the accumulation of particulate matter at the start of the reduction process, the lower the air pump speed, and the smaller the load on the air pump. In other words, the greater the accumulation of particulate matter at the start of the reduction process, the smaller the load on the air pump becomes due to the reduction process, thus allowing for a longer air pump drive duration. Therefore, the greater the accumulation of particulate matter at the start of the reduction process, the longer the extension time in the extended process can be achieved by this control device. Thus, this control device can adjust the air supply processing time in accordance with the air pump load. Furthermore, by maximizing the period of simultaneous air supply processing and oxygen supply processing while protecting the air pump, the filter regeneration process can be completed quickly.

[0015] In one embodiment of the vehicle control device, as part of the oxygen supply process, a stop process is performed to stop the fuel supply to the stopped cylinder and supply fuel to the remaining cylinders, wherein the stopped cylinder is one or more of the multiple cylinders of the internal combustion engine.

[0016] If a stop procedure is performed, oxygen is supplied to the filter via the cylinders that have stopped supplying fuel.

[0017] In one embodiment of the vehicle control device, as part of the oxygen supply process, an ignition stop process is performed that supplies fuel to each cylinder of the internal combustion engine without ignition.

[0018] If an ignition stop procedure is performed, fuel combustion in each cylinder is not carried out, so the oxygen contained in the unburned mixture is supplied to the filter.

[0019] One solution for the vehicle control device is applicable to vehicles equipped with a motor that drives the output shaft of the internal combustion engine. Furthermore, in this control device, as part of the oxygen supply process, a drive process is performed whereby the output shaft is driven by the motor while fuel supply to each cylinder of the internal combustion engine and ignition in each cylinder are stopped.

[0020] If a drag process is performed, the internal combustion engine acts like a pump, thus sending the air that has passed through the combustion chamber into the exhaust passage. Therefore, oxygen is supplied to the filter.

[0021] In one embodiment of the vehicle's control system, a lean operation process is performed as part of the oxygen supply process, which causes the air-fuel ratio of the mixture in each cylinder to be higher than the stoichiometric air-fuel ratio.

[0022] If a lean operation is performed, the air-fuel mixture contains residual oxygen that has not been completely consumed by combustion. Therefore, the oxygen in the exhaust gas is supplied to the filter.

[0023] According to another aspect of this disclosure, a vehicle control method that performs various processes described in association with any of the aforementioned vehicle control devices can also be embodied.

[0024] According to another aspect of this disclosure, a non-transitory, computer-readable recording medium storing a program that causes the processing device to perform various processes recorded in association with any of the aforementioned vehicle control devices may also be embodied. Attached Figure Description

[0025] Figure 1 This is a schematic diagram illustrating the relationship between the vehicle's control unit and the hybrid vehicle controlled by that control unit.

[0026] Figure 2 It is shown in Figure 1 The flowchart illustrates the process flow of the routine involving the regeneration of the exhaust passage filter in a hybrid vehicle.

[0027] Figure 3 It is shown in Figure 1 A flowchart of the process flow involving the reduction and extension processes performed in the air supply treatment of a hybrid vehicle.

[0028] Figure 4 It is shown Figure 3 A graph showing the relationship between filter buildup and supply airflow in reducing the amount of air deposited during the process.

[0029] Figure 5 It is shown Figure 3 A graph showing the relationship between filter buildup and extension time during extended processing.

[0030] Figure 6 It shows according to Figure 3 The flowchart shows the timeline of the shift of the marker F and the shift of the supplied air flow rate. Figure 6 Part (a) is a time graph showing the progression of the sign F. Figure 6 Part (b) is a time graph showing the shift in the supply air flow.

[0031] Figure 7 It is shown Figure 4 A graph showing the relationship between filter buildup and supply airflow in a modified example.

[0032] Figure 8 It is shown Figure 5 A graph showing the relationship between filter backlog and extension time in other change examples. Detailed Implementation

[0033] The phrase “at least one of A and B” in this specification shall be understood to mean “only A” or “only B” or “both A and B”.

[0034] The following is for reference Figures 1-6 The control device 500, which is a vehicle control device according to one embodiment, will be described.

[0035] <Composition of Vehicle 10>

[0036] First, by reference Figure 1 To illustrate the configuration of the vehicle 10 equipped with the control device 500. For example... Figure 1 As shown, vehicle 10 is equipped with an engine 11 and a second electric generator 32 as power sources. That is, vehicle 10 is a hybrid vehicle.

[0037] The engine 11 has an intake passage 12 and an exhaust passage 21. Furthermore, in Figure 1In the example shown, engine 11 has four cylinders. A throttle valve 13 is provided in the intake passage 12 to adjust the flow rate of the intake air flowing in the intake passage 12. In engine 11, one of multiple fuel injectors 14 is provided for each cylinder. Alternatively, multiple injectors 14 may be provided for each cylinder, or the number of injectors for each cylinder may be different. Additionally, in engine 11, one of multiple spark plugs 15 is provided for each cylinder to ignite the fuel-air mixture using a spark discharge. Alternatively, multiple spark plugs 15 may be provided for each cylinder, or the number of spark plugs for each cylinder may be different.

[0038] An upstream exhaust purification device 22 and a downstream exhaust purification device 23 are provided in the exhaust passage 21 of the engine 11. The downstream exhaust purification device 23 is located downstream of the upstream exhaust purification device 22 in the exhaust passage 21. The upstream exhaust purification device 22 is a NOx-storing three-way catalytic converter. In addition, the downstream exhaust purification device 23 is a particulate filter that captures particulate matter in the exhaust gas and carries the three-way catalytic converter. That is, the downstream exhaust purification device 23 is a filter provided in the exhaust passage 21.

[0039] An air supply device 26 is installed in the engine 11. The air supply device 26 includes an electric air pump 24 and an air supply passage 25. The air pump 24 is connected to the exhaust passage 21 via the air supply passage 25. The air supply passage 25 is connected to the portion of the exhaust passage 21 upstream of the upstream exhaust purification device 22. The air supply device 26 uses the air pump 24 to draw in outside air and introduces air into the exhaust passage 21 via the air supply passage 25.

[0040] The second electric generator 32 is connected to the battery 50 via a power control circuit (power control unit) 35. The second electric generator 32 is connected to the drive wheel 40 via a reduction gear 34.

[0041] Furthermore, the engine 11 is connected to the drive wheel 40 via a power distribution mechanism 30 and a reduction gear 34. Additionally, a first electric generator 31 is also connected to the power distribution mechanism 30. The first electric generator 31 is, for example, a three-phase AC electric generator. The power distribution mechanism 30 is a planetary gear mechanism capable of distributing the driving force of the engine 11 to the first electric generator 31 and the drive wheel 40.

[0042] The first electric generator 31 generates electricity by receiving driving force from the engine 11 and driving force from the drive wheel 40. Additionally, when starting the engine 11, the first electric generator 31 also functions as a starter for the output shaft, i.e., the crankshaft, of the engine 11. At this time, the first electric generator 31 functions as a motor that generates driving force based on the power supplied from the battery 50.

[0043] The first electric generator 31 and the second electric generator 32 are connected to the battery 50 via the power control circuit 35. The AC power generated by the first electric generator 31 is converted into DC power by the power control circuit 35 and used to charge the battery 50. That is, the power control circuit 35 functions as a converter.

[0044] Furthermore, the DC power from the battery 50 is converted to AC power by the power control circuit 35 and supplied to the second electric generator 32. Additionally, when the vehicle 10 decelerates, the second electric generator 32 generates electricity using the driving force from the drive wheels 40. The generated electricity then charges the battery 50. In other words, regenerative charging is performed in the vehicle 10. At this time, the second electric generator 32 functions as a generator. The AC power generated by the second electric generator 32 is converted to DC power by the power control circuit 35 and used to charge the battery 50.

[0045] Furthermore, when the first electric generator 31 functions as a starter, the power control circuit 35 supplies power to the first electric generator 31 by converting the DC power from the battery 50 into AC power.

[0046] <Regarding Control Device 500>

[0047] The control device 500 includes control circuits for controlling the engine 11, the first electric generator 31, and the second electric generator 32. The control device 500 includes an engine control circuit (control unit) 110 for controlling the engine 11. Additionally, the control device 500 includes a motor control circuit (control unit) 130 that controls the first electric generator 31 and the second electric generator 32 via a power control circuit 35. Furthermore, the control device 500 includes a comprehensive control circuit (control unit) 100 connected to the engine control circuit 110 and the motor control circuit 130 and overseeing the control of the vehicle 10. Moreover, these control circuits (control units) consist of processing circuits and memory storing programs executed by the processing circuits.

[0048] This control device 500 controls the engine 11, the first electric generator 31, and the second electric generator 32. That is, the control device 500 controls the power system of the vehicle 10. Detection signals from sensors installed in various parts of the vehicle 10 are input to the control device 500.

[0049] Specifically, the overall control circuit 100 is connected to an accelerator position sensor 101, a brake sensor 102, and a vehicle speed sensor 103. The accelerator position sensor 101 detects the accelerator opening. The brake sensor 102 detects the amount of brake operation. The vehicle speed sensor 103 detects the speed of the vehicle 10, i.e., the vehicle speed.

[0050] A crankshaft position sensor 111, a coolant temperature sensor 112, and an air flow meter 113 are connected to the engine control circuit 110. The crankshaft position sensor 111 outputs a crankshaft angle signal whenever the crankshaft rotates a certain angle. Based on the crankshaft angle signal, the engine control circuit 110 calculates the crankshaft rotation phase and the crankshaft speed, i.e., the internal combustion engine speed NE. The coolant temperature sensor 112 detects the temperature of the coolant in the engine 11, i.e., the coolant temperature THW. The air flow meter 113 detects the amount of intake air Ga drawn in through the intake passage 12.

[0051] An air-fuel ratio sensor 114 is installed in the exhaust passage 21. The air-fuel ratio sensor 114 is connected to the engine control circuit 110. The air-fuel ratio sensor 114 detects the air-fuel ratio.

[0052] Furthermore, the engine control circuit 110 is also connected to a differential pressure sensor 115 that detects the difference between the exhaust pressure of the portion between the upstream exhaust purification device 22 and the downstream exhaust purification device 23 in the exhaust passage 21 and the exhaust pressure of the portion downstream of the downstream exhaust purification device 23.

[0053] Additionally, an upstream temperature sensor 116 is connected to the engine control circuit 110 to detect the temperature of the exhaust gas between the upstream exhaust purification device 22 and the downstream exhaust purification device 23 in the exhaust passage 21. Furthermore, a downstream temperature sensor 117 is also connected to the engine control circuit 110 to detect the temperature of the exhaust gas downstream of the downstream exhaust purification device 23.

[0054] In addition, the motor control circuit 130 receives the current, voltage, and temperature of the battery 50 via the power control circuit 35. Based on these current, voltage, and temperature, the motor control circuit 130 calculates the ratio of the battery 50's charge margin to its charge capacity, i.e., the state of charge (SOC) value.

[0055] The engine control circuit 110 and the motor control circuit 130 are respectively connected to the overall control circuit 100 via communication lines. Furthermore, the overall control circuit 100, the motor control circuit 130, and the engine control circuit 110 exchange information and calculated information based on the detection signals input from the sensors via CAN communication, thereby sharing this information.

[0056] <Control of Vehicle 10>

[0057] The vehicle 10 configured as described above can drive the second electric generator 32 using the electricity stored in the battery 50, thereby enabling it to travel using only the second electric generator 32 to drive the drive wheels 40. Alternatively, it can also achieve hybrid driving by using both the engine 11 and the second electric generator 32 to drive the drive wheels 40.

[0058] The overall control circuit 100 outputs the required power and internal combustion engine speed of the engine 11 to the engine control circuit 110 based on the accelerator opening, brake operation, vehicle speed, and state of charge (SOC) value. Additionally, it outputs the required torque and target speed to the first electric generator 31 and the second electric generator 32 to the motor control circuit 130.

[0059] Engine control circuit 110 controls engine 11 to achieve the required power and internal combustion engine speed. Furthermore, engine control circuit 110 performs fuel injection control essentially in a manner that ensures the air-fuel ratio in each cylinder of engine 11 is the stoichiometric air-fuel ratio. Additionally, fuel injection and ignition in engine 11 are performed in the sequence of cylinder #1, cylinder #3, cylinder #4, and cylinder #2.

[0060] The motor control circuit 130 controls the first electric generator 31 and the second electric generator 32 respectively in a manner that achieves the required torque and target speed.

[0061] <Regarding the regeneration of particulate filters>

[0062] As described above, vehicle 10 includes a downstream exhaust purification device 23 in which a three-way catalytic converter is mounted on a particulate filter. The amount of particulate matter (DPM) accumulated in the particulate filter increases with the operation of engine 11. Therefore, in vehicle 10, when the amount of particulate matter (DPM) accumulated in the particulate filter increases to a certain level, the particulate filter needs to be regenerated by burning the accumulated particulate matter. In vehicle 10, the particulate matter accumulated in the particulate filter is burned by introducing oxygen into the particulate filter while it is sufficiently heated.

[0063] <About Recycling Process>

[0064] exist Figure 2 The diagram shows the processing steps in the routine involved in the regeneration process performed by the control device 500. Figure 2 The example shown is implemented by a processing circuit that repeatedly executes a program stored in memory at predetermined intervals. Furthermore, the step numbers of each process are indicated below by numbers beginning with "S".

[0065] exist Figure 2In the illustrated routine, the control device 500 first obtains the internal combustion engine speed NE, the charging efficiency η, and the coolant temperature THW (S10). The charging efficiency η is calculated by the engine control circuit 110 based on the intake air volume Ga and the internal combustion engine speed NE. Next, the control device 500 calculates the update amount ΔDPM of the buildup DPM based on the internal combustion engine speed NE, the charging efficiency η, and the coolant temperature THW (S12). Specifically, the control device 500 calculates the amount of particulate matter in the exhaust gas discharged into the exhaust passage 21 based on the internal combustion engine speed NE, the charging efficiency η, and the coolant temperature THW. In addition, the control device 500 calculates the temperature of the downstream exhaust purification device 23 based on the detection values ​​of the upstream temperature sensor 116 and the downstream temperature sensor 117. Then, the control device 500 calculates the update amount ΔDPM based on the amount of particulate matter in the exhaust gas and the temperature of the downstream exhaust purification device 23.

[0066] Next, the control device 500 adds the update amount ΔDPM to the accumulated amount DPM to obtain a new accumulated amount DPM. This update of the accumulated amount DPM is performed (S14). Next, the control device 500 determines whether the flag F is "1" (S16). If the flag F is "1", it indicates that the oxygen supply process (described later) is being performed for the regeneration process used to burn off particulate matter from the downstream exhaust purification device 23. On the other hand, if the flag F is "0", it indicates that no oxygen supply process is being performed. If the control device 500 determines that the flag F is "0" (S16: No), it determines whether the accumulated amount DPM is above the regeneration execution value DPMH (S18). The regeneration execution value DPMH is a threshold used to determine whether a state requiring the removal of particulate matter is reached based on the accumulated amount DPM being above the regeneration execution value DPMH.

[0067] If the control device 500 determines that the accumulation amount DPM is greater than or equal to the regeneration execution value DPMH (S18: Yes), it determines whether the execution conditions for the regeneration process of the downstream exhaust purification device 23 are met (S20). Here, the execution conditions are set as the condition that the logical AND of the following conditions (A) to conditions (C) is true.

[0068] Condition (A): The required power of engine 11 is above the predetermined value.

[0069] Condition (B): The internal combustion engine speed NE is above the predetermined speed.

[0070] Condition (C): The conditions under which torque compensation processing of S24 can be performed.

[0071] When the control device 500 determines that the logical AND operation is true (S20: Yes), it performs an oxygen supply process for regeneration, thereby setting the flag F to "1" (S22). That is, the control device 500 stops the injection of fuel from the injector 14 of cylinder #1. Furthermore, the control device 500 makes the air-fuel ratio of the mixture in cylinders #2 to #4 richer than the stoichiometric air-fuel ratio. In other words, the oxygen supply process in this embodiment is a process of stopping the fuel supply to one or more cylinders that are considered as stopped cylinders and supplying fuel to the remaining cylinders. The stopping process promotes the oxidation reaction in the upstream exhaust purification device 22 and the downstream exhaust purification device 23 by discharging oxygen and unburned fuel into the exhaust passage 21. Furthermore, the stopping process is used to burn off particulate matter captured by the downstream exhaust purification device 23 by raising the temperature of the upstream exhaust purification device 22 and the downstream exhaust purification device 23. That is, the control device 500 increases the temperature of the exhaust gas by discharging oxygen and unburned fuel into the exhaust passage 21, thereby causing the unburned fuel to burn in the exhaust purification devices (22, 23). Therefore, the temperature of the downstream exhaust purification device 23 can be increased. In addition, by supplying oxygen to the downstream exhaust purification device 23, the particulate matter captured by the downstream exhaust purification device 23 can be burned off.

[0072] Furthermore, the stop cylinder where fuel supply is stopped is not limited to cylinder #1. For example, the stop cylinders where fuel supply is stopped can be switched sequentially in a manner that avoids an imbalance in the number of times fuel supply is stopped.

[0073] Next, the control unit 500 performs a process (S24) to compensate for the torque variation of the crankshaft of the engine 11 caused by the cessation of combustion control of cylinder #1. In this process, the power control circuit 35 adds a compensation torque to the required torque for driving of the second electric generator 32. Furthermore, the motor control circuit 130 operates the power control circuit 35 based on the required torque with the compensation torque added.

[0074] Furthermore, the conditions for performing this torque compensation process are that the second electric generator 32 does not produce any abnormalities and the battery 50 has the power required to perform the torque compensation process.

[0075] On the other hand, when the control device 500 determines that the flag F is "1" (S16: Yes), it determines whether the accumulation amount DPM is below the stop threshold DPML (S26). The stop threshold DPML is a threshold used to determine whether the regeneration process can be stopped based on the accumulation amount DPM being below the stop threshold DPML. When the accumulation amount DPM is below the stop threshold DPML (S26: Yes), the control device 500 stops the regeneration process, thereby setting the flag F to "0" (S28).

[0076] Furthermore, if the control device 500 has completed the processing of S24 and S28, or if a negative determination is made during the processing of S18 and S20, it temporarily terminates the process. Figure 2 The example shown.

[0077] <Regarding Air Supply Management>

[0078] To rapidly preheat the catalyst in the upstream exhaust purification device 22 to its activation temperature, the control device 500 uses the air supply device 26 to perform air supply processing. Specifically, the control device 500 introduces air into the exhaust passage 21 via the air supply passage 25 by driving the air pump 24 for a predetermined time TAI. Thus, air is supplied to the upstream exhaust purification device 22. The air supply processing is performed during the low-temperature start-up of the engine 11. Specifically, the control device 500 performs the air supply processing based on the "execution conditions of the air supply processing being met". The execution conditions of the air supply processing are (i) the water temperature THW is below a threshold (e.g., below 60°C), (ii) the engine 11 has been started, (iii) the water temperature THW is above 0°C, and (iv) there are no abnormalities in the air pump 24. In addition, (iii) the water temperature THW is above 0°C is a condition used to prevent the air pump 24 from being driven when the condensate in the air supply passage 25 is frozen.

[0079] If air is supplied to the upstream exhaust purification device 22 by performing air supply processing during the cold start of the engine 11, preheating is promoted by the oxidation reaction in the upstream exhaust purification device 22.

[0080] While the control device 500 is operating, if the coolant temperature (THW) decreases due to continuous operation where only the second electric generator 32 is used as the driving source for the vehicle 10 and the engine 11's motor is not used, the engine 11 will be started. Therefore, the air supply process is only performed once during the continuous operation of the control device 500 and is not performed thereafter. In addition, sometimes the air supply process is not performed when the coolant temperature (THW) is already high.

[0081] If air supply processing and oxygen supply processing for regeneration are performed simultaneously, the oxygen supply processing can supplement the oxygen that is insufficient by oxygen supply processing alone. Therefore, the regeneration of the downstream exhaust gas purification unit 23 is completed quickly. However, if air supply processing and oxygen supply processing are performed simultaneously, the downstream exhaust gas purification unit 23 may overheat due to an excess of oxygen supplied to it.

[0082] Therefore, the control device 500 of this embodiment performs air supply processing. Figure 3 The routine shown adjusts the drive amount of the air pump 24 in the air supply process.

[0083] exist Figure 3 The diagram shows the processing steps in the routines involved in the reduction and extension processes performed by the control device 500 in the air supply process. Figure 3 The example shown is implemented by the processing circuit repeatedly executing a program stored in memory, for example, at predetermined cycles, before performing a reduction process during the execution of the air supply process. Furthermore, the step numbers of each process are indicated below using numbers prefixed with "S".

[0084] exist Figure 3 In the example shown, control device 500 first determines whether flag F is "1" (S30). This determination process is performed in conjunction with reference to... Figure 2 The process described in S16 is the same. When the control device 500 determines that flag F is "1" (S30: Yes), it reduces the supply air flow rate QAI based on the accumulation amount DPM (S32). Furthermore, the supply air flow rate QAI is the amount of air supplied to the exhaust passage 21 per unit time by the air supply device 26. The air supply device 26 supplies air by driving the air pump 24. Therefore, the control device 500 adjusts the supply air flow rate QAI by controlling the rotational speed of the air pump 24. In the process of S32, the control device 500 determines the rotational speed of the air pump 24 based on the accumulation amount DPM.

[0085] like Figure 4 As shown, when the buildup amount DPM is below the stop threshold DPML (i.e., oxygen supply processing is not performed), the rotational speed of the air pump 24 is set so that the supply air flow rate QAI becomes the base flow rate Qbase. In the process of S32, the rotational speed of the air pump 24 is set as follows: Figure 4 As shown, when the accumulated amount (DPM) exceeds the stop threshold (DPML), the higher the accumulated amount (DPM), the lower the supply air flow rate (QAI). Furthermore, the rotational speed of the air pump 24 is determined so that the supply air flow rate (QAI) is "0," i.e., the air pump 24 is stopped, when the accumulated amount (DPM) is above the threshold (D1). Moreover, the threshold (D1) is set based on a lower limit of the accumulated amount (DPM) that raises concerns about overheating of the downstream exhaust purification unit 23 due to simultaneous oxygen supply processing and air supply processing. The threshold (D1) is a value greater than the regeneration execution value (DPMH).

[0086] That is, the processing in S32 is a reduction processing related to the air supply volume under air supply processing. The reduction processing makes the air supply volume per unit time in the air supply processing when oxygen supply processing and air supply processing are performed simultaneously less than the air supply volume per unit time in the air supply processing when oxygen supply processing and air supply processing are not performed simultaneously. In other words, in the processing of S32, when air supply processing is performed, the air supply volume per unit time in the air supply processing is made less when oxygen supply processing is performed simultaneously than when oxygen supply processing is not performed simultaneously. Furthermore, when the accumulation amount DPM becomes so high that there is concern about overheating of the downstream exhaust purification device 23, the control device 500 stops the air supply processing by stopping the air pump 24.

[0087] After the speed of the air pump 24 is reduced through the process in S32, the control device 500 determines the extension time TEx (S34) based on the accumulation amount DPM. As described above, the air supply process is the process of driving the air pump 24 for a predetermined time TAI. When no oxygen supply process is performed, the predetermined time TAI is the basic time Tbase. For example, the basic time Tbase is 1 minute. The extension time TEx is the time during the air supply process for which the air pump 24 continues to be driven even after the basic time Tbase, that is, the time for extending the predetermined time TAI of driving the air pump 24.

[0088] like Figure 5 As shown, the extension time TEx is "0" when the accumulated amount DPM is below the stop threshold DPML, i.e., when no oxygen supply process is performed. The extension time TEx is also determined to be "0" when the accumulated amount DPM is above the threshold D1. That is, when the air pump 24 is stopped, the extension time TEx is determined to be "0". When the accumulated amount DPM is in a range greater than the stop threshold DPML but less than the threshold D1, in the process of S34, the extension time TEx is determined in a way that the higher the accumulated amount DPM, the longer the extension time TEx. Furthermore, the maximum value Tmax of the extension time TEx is, for example, a value shorter than several minutes.

[0089] After the extension time TEx is determined through the process in S34, the control device 500 updates the predetermined time TAI by adding the extension time TEx to the base time Tbase to obtain the new predetermined time TAI. That is, the processes in S34 and S36 are extended processes that increase the amount of accumulation DPM at the beginning of the process, thereby increasing the extension time TEx and extending the predetermined time TAI.

[0090] After completing the processing of S36, the control device 500 terminates the routine.

[0091] On the other hand, if the control device 500 determines that the flag F is "0" (S30: No), it does not execute the processing of S32 to S36, and directly terminates the routine temporarily.

[0092] <The function of this implementation method>

[0093] Next, by reference Figure 6 The function of the control device 500 will be explained below. Furthermore, Figure 6 This is a time graph showing the indicator F and the shift of the supplied air flow rate QAI when oxygen supply processing is started midway through an ongoing air supply process. Furthermore, in Figure 6 In the example, the shift of the supply air flow rate QAI without performing reduced processing and extended processing is shown with a single-dot line.

[0094] In such Figure 6 As shown in part (b), at the start of the air supply process at time t1, the supply air flow rate QAI increases due to the driving air pump 24. At this time, since no oxygen supply process is performed, the flag F is "0" (S30: No).

[0095] In such Figure 6 As shown in part (a), at the start of the oxygen supply process at time t2, flag F becomes "1" (S30: Yes). Furthermore, a reduction process is performed (S32). Therefore, as... Figure 6 As shown in section (b), the supply air flow rate QAI is reduced. In addition, an extension process (S34) is performed, so the predetermined time TAI is extended to the length obtained by adding the extension time TEx to the base time Tbase.

[0096] Therefore, from time t2 to time t4, oxygen supply processing and air supply processing with reduced supply air flow rate QAI are performed simultaneously. At time t4, after a predetermined time TAI, the drive of air pump 24 stops, thus ending the air supply processing. Furthermore, since it takes several tens of minutes for the regeneration process of the downstream exhaust purification unit 23 based on oxygen supply processing to be completed, oxygen supply processing continues even after time t4.

[0097] In contrast, Figure 6 Part (b) shows the supply air flow rate QAI of the comparative example where the reduction and extension processes are not performed with a single-dotted line. As shown by the single-dotted line, in the comparative example where the reduction and extension processes are not performed, the supply air flow rate QAI remains at the basic flow rate Qbase even after the oxygen supply process begins at time t2. Furthermore, as shown by the single-dotted line, in the comparative example, the drive of the air pump 24 stops at time t3 after the basic time Tbase has elapsed, and therefore the air supply process ends.

[0098] If air supply processing and oxygen supply processing are performed simultaneously, the regeneration of the downstream exhaust purification unit 23 is completed quickly. However, if air supply processing and oxygen supply processing are performed simultaneously without reducing the supply air flow rate QAI, as in the comparative example, the downstream exhaust purification unit 23 may overheat due to excessive oxygen supply.

[0099] In contrast, the control device 500 of this embodiment performs a reduction process while performing air supply processing. The reduction process reduces the supply air flow rate QAI in the air supply processing compared to when oxygen supply processing is not performed simultaneously. Therefore, according to the control device 500, the amount of oxygen supplied by the air supply device 26 is reduced when air supply processing and oxygen supply processing are performed simultaneously.

[0100] <Effects of this implementation method>

[0101] (1) The control device 500 can supplement the oxygen supply that is insufficient by oxygen supply alone using the air supply device 26, and can suppress the supply of excess oxygen. That is, the control device 500 can quickly complete the regeneration process while suppressing the overheating of the downstream exhaust purification device 23.

[0102] (2) As by reference Figure 4 As explained, the control device 500 reduces the amount of accumulated air (DPM) at the start of the process, resulting in a lower supply air flow rate (QAI). A higher DPM accumulation makes it easier for the downstream exhaust purification unit 23 to overheat due to oxygen supply issues. By controlling the air supply in accordance with the ease of overheating, the control device 500 can suppress overheating.

[0103] (3) The electric air pump 24 cannot sustain high-load operation for an extended period. Therefore, the control device 500 protects the air pump 24 by limiting the operation at a predetermined speed to a predetermined time TAI. When the speed is reduced through the reduction process, the load on the air pump 24 is reduced. Therefore, the operation time can be extended. Thus, in this control device 500, when the reduction process is performed, an extension process is performed that extends the time for driving the air pump 24 beyond the basic time Tbase. Therefore, by protecting the air pump 24 and extending the period during which air supply processing and oxygen supply processing are performed simultaneously, this control device 500 enables the regeneration process of the downstream exhaust gas purification device 23 to be completed quickly.

[0104] (4) When the accumulation amount DPM at the start of the reduction process results in a lower rotational speed for the air pump 24, the accumulation amount DPM at the start of the reduction process also results in a lower load on the air pump 24. That is, the higher the accumulation amount DPM at the start of the reduction process, the lower the load on the air pump 24 becomes due to the reduction in processing, thus allowing for a longer driving time for the air pump 24. Therefore, the control device 500, by referring to... Figure 5 As explained, the greater the initial buildup (DPM) at the start of processing, the longer the extended processing time (TEx) becomes. Therefore, the control device 500 can adjust the air supply processing time in accordance with the load on the air pump 24. Furthermore, by protecting the air pump 24 and maximizing the duration of simultaneous air supply processing and oxygen supply processing, the regeneration process can be completed quickly.

[0105] <Example of Change>

[0106] This embodiment can be implemented by modifications as follows. This embodiment and the following modifications can be combined and implemented within the scope of technical inconsistency.

[0107] • In the above-described embodiments, such as Figure 4 The diagram illustrates an example of reducing the rotational speed of air pump 24 in a reduction process by decreasing the supply air flow rate (QAI) as the accumulation volume (DPM) increases. However, the reduction scheme for the supply air flow rate (QAI) in a reduction process is not limited to this approach. For example, as... Figure 7 As shown, the supply airflow rate QAI can also be set separately according to multiple levels (grades) of the buildup volume DPM. Figure 7 In the illustrated modification example, when the buildup amount DPM is greater than the stop threshold DPML but less than the threshold D2, the supply air flow rate QAI is set to Q2. Furthermore, threshold D2 is smaller than threshold D1. Conversely, when the buildup amount DPM is greater than threshold D2 but less than threshold D1, the supply air flow rate QAI is set to Q1. Furthermore, Q1 is smaller than Q2. In this way, the supply air flow rate QAI, set by reducing the processing, can also be set step-by-step according to the buildup amount DPM.

[0108] • In the above-described embodiments, such as Figure 5 The diagram illustrates an example of extending the predetermined time TAI in an extension process in which a higher DPM results in a longer extension time TEx. However, the extension scheme for the predetermined time TAI in an extension process is not limited to this approach. For example, as... Figure 8 As shown, the extension time TEx can also be set when the accumulated amount DPM is too high, that is, when the supplied air flow rate QAI is too low due to reduced processing, and the extension time is extended. Figure 8In the illustrated modification example, the extension time TEx is set only when the stacked quantity DPM is above the threshold D3 and below the threshold D1. Therefore, the extension process is essentially limited to situations where the stacked quantity DPM is above the threshold D3 and below the threshold D1. Furthermore, the threshold D3 is smaller than the threshold D1. Alternatively, the extension time TEx set by the extension process can be set incrementally based on the stacked quantity DPM.

[0109] • The extended processing can also be omitted. That is, in the air supply processing, the reduction processing is performed, but the extended processing is not performed, and the air pump 24 is always driven during the basic time Tbase.

[0110] In the above-described embodiment, an example is shown whereby a stop process is performed as an oxygen supply process, which stops the fuel supply to one or more cylinders of the engine 11 and supplies fuel to the remaining cylinders. In contrast, the oxygen supply process is not limited to a stop process. The oxygen supply process can be any process that supplies oxygen that has passed through the combustion chamber of the engine 11 to the filter via the exhaust passage 21.

[0111] • As an oxygen supply process, an ignition stop process can also be performed, in which fuel is supplied to each cylinder of engine 11 but no ignition is performed. If the ignition stop process is performed, since the fuel in each cylinder is not burned, the oxygen contained in the unburned mixture is supplied to the filter.

[0112] • As an oxygen supply process, a crankshaft-driving process can also be performed by using a motor such as a first electric generator 31 or a second electric generator 32 to drive the crankshaft while the fuel supply to each cylinder in the engine 11 and the ignition in each cylinder are stopped. If the driving process is performed, the engine 11 functions like a pump, and air passing through the combustion chamber is sent into the exhaust passage 21. Therefore, oxygen is supplied to the filter.

[0113] • As an oxygen supply process, a lean operation process can also be performed, which makes the air-fuel ratio of the mixture in each cylinder higher than the stoichiometric air-fuel ratio. If a lean operation process is performed, the mixture contains residual oxygen that has not been completely burned. Therefore, the oxygen contained in the exhaust gas is supplied to the filter.

[0114] While the example shown is an inline 4-cylinder engine with four cylinders, the internal combustion engine controlled by the control device 500 is not limited to this. That is, the internal combustion engine is not limited to a 4-cylinder engine. Alternatively, the internal combustion engine could be a V-type engine, a horizontally opposed engine, or a W-type engine, each with an exhaust gas purification device for each cylinder bank. In this case, the stopping process can be configured to stop the fuel supply to at least one cylinder in each cylinder bank during one cycle. Therefore, sufficient oxygen can be supplied to the exhaust gas purification devices of each cylinder bank in the V-type engine, etc.

[0115] An example is shown where an upstream exhaust purification device 22 and a downstream exhaust purification device 23 are provided, with the downstream exhaust purification device 23 being a particulate filter. The configuration of the exhaust purification device is not limited to this configuration. The same configuration as described above can be applied to any control device 500 that controls a vehicle 10 equipped with an internal combustion engine that is equipped with at least a particulate filter.

[0116] The composition of the power system in vehicle 10 is not limited to... Figure 1 The configuration illustrated above. Any control device 500 that can control a vehicle 10 capable of performing torque compensation processing using a motor can be configured in the same way as described in the above embodiment.

[0117] • Alternatively, torque compensation processing may not be performed. Therefore, vehicle 10 may not be a hybrid vehicle equipped with a motor.

[0118] • The predetermined conditions for allowing the regeneration process to proceed are not limited to the conditions exemplified in the above embodiments. For example, regarding the three conditions (A) to (C) above, only two of them may be included, or for example, only one may be included. Furthermore, the predetermined conditions may include conditions other than the three conditions mentioned above, or none of the three conditions may be included.

[0119] • As an estimate of the DPM (Distribution Per Mille), it is not limited to Figure 2 The processing is illustrated in the example. For instance, the buildup amount DPM can also be estimated based on the pressure difference between the upstream and downstream sides of the downstream exhaust purification device 23 detected by the differential pressure sensor 115 and the intake air volume Ga. Specifically, the buildup amount DPM when the pressure difference is large is estimated to be a larger value than the buildup amount DPM when the pressure difference is small. Thus, even if the pressure difference is the same, the buildup amount DPM when the intake air volume Ga is small can be estimated to be a larger value than the buildup amount DPM when the intake air volume Ga is large.

[0120] • The downstream exhaust purification device 23 is not limited to a filter carrying a three-way catalytic converter; it may be any filter. Furthermore, the downstream exhaust purification device 23 is not limited to a device downstream of the upstream exhaust purification device 22 located in the exhaust passage 21. The same configuration as described above can also be applied to the control device 500 of the vehicle 10 that controls the engine 11, which performs air supply processing to promote preheating of the filter carrying a three-way catalytic converter, equivalent to the downstream exhaust purification device 23 described above.

[0121] The control circuitry of the control device 500 includes an engine control circuit 110, a motor control circuit 130, and an overall control circuit 100. These control circuits (control units) can be configured as one or more processors (processing devices) that execute various processes according to computer programs (software). Alternatively, these control circuits (control units) can be configured as one or more application-specific integrated circuits (ASICs) or other dedicated hardware circuits that execute at least a portion of the various processes. Furthermore, these control units can also be configured as a circuitry including combinations thereof. The processor includes a CPU and memories such as RAM and ROM, which store program code or instructions configured to cause the CPU to execute processes. Memory, or computer-readable medium, includes all usable media that can be accessed using a general-purpose or special-purpose computer.

[0122] • As for vehicle 10, it is not limited to a series-parallel hybrid vehicle; for example, it could also be a parallel hybrid vehicle or a series hybrid vehicle. However, it is not limited to hybrid vehicles; for example, vehicle 10 could also be a vehicle 10 whose power generation device is only engine 11.

[0123] Furthermore, the expression "at least one" as used in this specification means "more than one" of the desired options. For example, if the number of options is two, the expression "at least one" as used in this specification means "only one option" or "both options". As another example, if the number of options is three or more, the expression "at least one" as used in this specification means "only one option" or "any combination of two or more options".

Claims

1. A vehicle control device, the control device comprising a control circuit, wherein the vehicle to which the control device is used is equipped with an internal combustion engine, the control circuit being configured to execute: Air supply processing involves supplying air to a filter in an exhaust passage by driving an air pump of an air supply device. The internal combustion engine includes the air supply device, which has an air supply passage connected to a portion of the exhaust passage upstream of the filter and the air pump. The air supply processing involves driving the air pump to introduce air into the exhaust passage via the air supply passage, thereby supplying the air introduced into the exhaust passage to the filter. Oxygen supply processing involves supplying oxygen from the combustion chamber of the internal combustion engine to the filter via the exhaust passage; and A reduction process related to the air supply volume under the aforementioned air supply treatment, wherein the reduction process causes the air supply volume per unit time in the air supply treatment when the oxygen supply treatment and the air supply treatment are performed simultaneously to be less than the air supply volume per unit time in the air supply treatment when the oxygen supply treatment and the air supply treatment are not performed simultaneously. The control circuit is configured to, when the oxygen supply process is started while the air supply process is being performed, reduce the amount of air supplied per unit time in the air supply process and extend the duration of the air supply process.

2. The vehicle control device according to claim 1, In the reduction process, the greater the accumulation of particulate matter in the filter at the start of the reduction process, the less air is supplied per unit time.

3. The vehicle control device according to claim 1 or 2, The air pump is an electric air pump. Without simultaneously performing the air supply process and the oxygen supply process, the air supply process is the process of driving the electrically powered air pump at a predetermined speed for a predetermined time. The reduction process involves making the speed of the air pump lower than the predetermined speed. The control circuit is configured to perform an extension process that extends the time for driving the air pump when the reduction process is executed during the air supply process.

4. The vehicle control device according to claim 3, In the extended process, the greater the amount of particulate matter accumulated in the filter at the start of the reduction process, the longer the extension time for driving the air pump will be.

5. The vehicle control device according to claim 1, The control circuit is configured to, as part of the oxygen supply process, execute a stop process that stops the fuel supply to one or more cylinders of the internal combustion engine and supplies fuel to the remaining cylinders.

6. The vehicle control device according to claim 1, The control circuit is configured to perform an ignition stop process, which, as part of the oxygen supply process, supplies fuel to each cylinder of the internal combustion engine without ignition.

7. The vehicle control device according to claim 1, The vehicle to which the control circuit is applied has a motor that drives the output shaft of the internal combustion engine. The control circuit is configured to perform, as part of the oxygen supply process, a drive process in which the output shaft is driven by the motor while the fuel supply to each cylinder of the internal combustion engine and the ignition in each cylinder are stopped.

8. The vehicle control device according to claim 1, The control circuit is configured to perform a lean operation process, as part of the oxygen supply process, to make the air-fuel ratio of the mixture in each cylinder higher than the stoichiometric air-fuel ratio.

9. A vehicle control method, wherein the vehicle to which the control method is applied is equipped with an internal combustion engine, the control method comprising the following steps: An air supply process is performed by supplying air to a filter in an exhaust passage by driving an air pump of an air supply device. The internal combustion engine has the air supply device, which has an air supply passage connected to a portion of the exhaust passage upstream of the filter and the air pump. The air supply process introduces air into the exhaust passage via the air supply passage by driving the air pump, thereby supplying the air introduced into the exhaust passage to the filter. The process involves supplying oxygen from the combustion chamber of the internal combustion engine to the filter via the exhaust passage. and A reduction process is performed related to the air supply volume under the aforementioned air supply process, which reduces the air supply volume per unit time in the air supply process when both the oxygen supply process and the air supply process are performed simultaneously, compared to the air supply volume per unit time in the air supply process when both the oxygen supply process and the air supply process are not performed simultaneously. In the control method, when the oxygen supply process is started while the air supply process is being performed, the amount of air supplied per unit time in the air supply process is reduced and the duration of the air supply process is extended.

10. A non-transitory computer-readable storage medium storing a program that causes a processing device to perform control processing of a vehicle, the vehicle to which the control processing is applied being equipped with an internal combustion engine, the control processing comprising the following steps: An air supply process is performed by supplying air to a filter in an exhaust passage by driving an air pump of an air supply device. The internal combustion engine has the air supply device, which has an air supply passage connected to a portion of the exhaust passage upstream of the filter and the air pump. The air supply process introduces air into the exhaust passage via the air supply passage by driving the air pump, thereby supplying the air introduced into the exhaust passage to the filter. The process involves supplying oxygen from the combustion chamber of the internal combustion engine to the filter via the exhaust passage. and A reduction process is performed related to the air supply volume under the aforementioned air supply process, which reduces the air supply volume per unit time in the air supply process when both the oxygen supply process and the air supply process are performed simultaneously, compared to the air supply volume per unit time in the air supply process when both the oxygen supply process and the air supply process are not performed simultaneously. In the control process, if the oxygen supply process is started while the air supply process is being performed, the amount of air supplied per unit time in the air supply process is reduced and the duration of the air supply process is extended.

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