Vehicle control device

Abstract

To reproduce a filter without damaging the filter.SOLUTION: Enabled are: first fuel cut processing for alternatively repeating, while continuing to operate an internal combustion engine, a stop pattern for stopping a fuel supply to cylinders continuously for M-piece and a combustion pattern for supplying the fuel to cylinders continuously for N-piece; and processing of calculating, as a first temperature T1, an estimated temperature of a filter with an assumption that a quantity of current particulate materials accumulated in the filter has been reduced to an end accumulation amount by executing the first fuel cut processing. The first fuel cut processing is executed in a case where a first start condition is established (step S200). The first start condition includes all the following: an automatic transmission is in a neutral range (Yes for step S110); the vehicle is traveling on a downhill road (Yes for steps 140, S150); and the first temperature T1 is equal to or lower than a set temperature TA (Yes for step S190).SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a vehicle control device. [Background technology]

[0002] The vehicle disclosed in Patent Document 1 has an internal combustion engine and a control device. The internal combustion engine has a plurality of cylinders, an exhaust passage, a catalyst, and a filter. The exhaust passage is connected to the cylinders. The catalyst is located midway through the exhaust passage. The catalyst purifies the exhaust gas. The filter is located downstream of the catalyst in the exhaust passage. The filter collects particulate matter in the exhaust gas.

[0003] When the amount of particulate matter deposited on the filter becomes large, the control device performs a filter regeneration process. That is, the control device makes the air-fuel ratio of some of the cylinders leaner than the theoretical air-fuel ratio, while making the air-fuel ratio of the remaining cylinders richer than the theoretical air-fuel ratio. In this case, oxygen discharged from the former cylinders and unburned fuel discharged from the latter cylinders are combusted in a catalyst. When the resulting high-temperature exhaust gas reaches the filter, the particulate matter deposited on the filter is combusted. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-085965 A Summary of the Invention [Problem to be solved by the invention]

[0005] In a vehicle such as that described in Patent Document 1, the internal combustion engine may be coupled to an automatic transmission. When the vehicle is traveling downhill, the shift range of the automatic transmission may be in the neutral range. In such a situation where the vehicle is traveling downhill in the neutral range, the vehicle can travel without requiring the output of the internal combustion engine. In this case, there are few constraints on the output of the internal combustion engine when the vehicle travels. Therefore, the control device is allowed to increase or decrease the amount of fuel supplied to the cylinder, that is, to perform, for example, the above-mentioned filter regeneration process. Therefore, in order to increase the opportunity for filter regeneration, it is conceivable to perform filter regeneration during the period when the vehicle is traveling downhill in the neutral range.

[0006] When the filter is regenerated, the temperature of the filter rises as particulate matter is burned. If the temperature of the filter becomes excessively high, the filter may be damaged. Therefore, even if there is no restriction on the output of the internal combustion engine when traveling downhill in the neutral range, if the filter regeneration is prioritized without any consideration of the filter condition, the filter may be damaged. [Means for solving the problem]

[0007] A vehicle control device for solving the above problem is applied to a vehicle having an internal combustion engine including a plurality of cylinders, a filter that collects particulate matter in exhaust gas discharged from the cylinders, and a crankshaft, an input shaft connected to the crankshaft, an output shaft connected to drive wheels, and a transmission mechanism that reduces the rotation of the input shaft and transmits it to the output shaft, the transmission mechanism being an automatic transmission that can be switched to a neutral range in which torque is not transmitted from the input shaft to the output shaft, and the vehicle control device includes a stop pattern for stopping the supply of fuel to M consecutive cylinders in the order of the cylinders that will enter the combustion stroke, where "M" and "N" are integers of 1 or more, and a stop pattern for stopping the supply of fuel to N consecutive cylinders in the order of the cylinders that will enter the combustion stroke. The vehicle is capable of executing a fuel cut process that alternately repeats a combustion pattern in which fuel is supplied to a cylinder while continuing to operate the internal combustion engine, and a first estimation process that calculates an estimated temperature of the filter as a first temperature when it is assumed that the current amount of particulate matter accumulated in the filter has been reduced to a predetermined ending accumulation amount by executing the fuel cut process, and the fuel cut process is executed when a predetermined first start condition is met, and the first start condition includes the following conditions all being met: the transmission mechanism is in the neutral range, the vehicle is traveling on a downhill road, and the first temperature is equal to or lower than a predetermined set temperature.

[0008] In the above configuration, the control device calculates a first temperature as an estimated future temperature of the filter if a fuel cut process is performed, based on the current amount of particulate matter accumulated in the filter. The control device then performs the fuel cut process on the condition that the first temperature is equal to or lower than a set temperature. This allows the control device to regenerate the filter only when the filter does not overheat even if the fuel cut process is performed, among the opportunities to travel downhill in the neutral range. Therefore, the control device can regenerate the filter without damaging it when traveling downhill in the neutral range.

[0009] In a vehicle control device, when the fuel cut process executed with predetermined values ​​of "M" and "N" is defined as a first fuel cut process, and the fuel cut process executed with predetermined values ​​of "M" and "N" where the value of "M / N" is greater than that of the first fuel cut process is defined as a second fuel cut process, a second estimation process can be further executed to calculate, during execution of the first fuel cut process, an estimated temperature of the filter when it is assumed that the current amount of particulate matter deposited in the filter has been reduced to the termination deposition amount by executing the second fuel cut process, as a second temperature, and the second fuel cut process is executed when a predetermined second start condition is satisfied, and the second start condition may include the satisfaction of all of the following: the second temperature is equal to or lower than the set temperature, and the current amount of particulate matter deposited in the filter is equal to or lower than the predetermined set deposition amount.

[0010] When the second fuel cut process is performed, the ratio of cylinders to which fuel supply is stopped increases compared to when the first fuel cut process is performed, and therefore the amount of oxygen supplied to the filter increases. In other words, the second fuel cut process makes it easier for the filter temperature to rise compared to when the first fuel cut process is performed. Here, the filter has a portion where particulate matter is likely to accumulate. If a large amount of oxygen is supplied to such a portion where a large amount of particulate matter accumulates, the portion where a large amount of particulate matter accumulates may become locally hot, causing the filter to generate abnormal heat. In consideration of this, the control device regenerates the filter on the condition that the current amount of particulate matter accumulated on the filter is equal to or less than the set accumulation amount. In other words, the control device performs the second fuel cut process only when the filter is unlikely to generate abnormal heat even if the amount of oxygen supplied to the filter increases by performing the second fuel cut process.

[0011] Furthermore, the control device calculates a second temperature as an estimated future temperature of the filter if the second fuel cut process is performed based on the current amount of particulate matter accumulated in the filter.Then, the control device performs the second fuel cut process on the condition that the second temperature is equal to or lower than a set temperature.In other words, the control device performs the second fuel cut process only in a situation where the filter will not overheat even if the second fuel cut process is performed.

[0012] With this configuration, the control device can prevent damage to the filter when regenerating the filter, and can promote filter regeneration by supplying a large amount of oxygen to the filter under circumstances where the filter will not be damaged. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram of a vehicle. [Diagram 2] FIG. 2 is a flowchart showing a processing procedure of the first determination processing. [Diagram 3] FIG. 3 is a flowchart showing a processing procedure of the second determination processing. [Figure 4] FIG. 4 is a flowchart showing the procedure of the end determination process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of a vehicle control device will be described with reference to the drawings. <Vehicle Overview> 1, a vehicle 500 has an internal combustion engine 10. The internal combustion engine 10 is a drive source of the vehicle 500.

[0015] The internal combustion engine 10 has an engine body 10A and a crankshaft 31. The engine body 10A has a plurality of cylinders 11. Each cylinder 11 is a space partitioned in the engine body 10A. Although not shown, each cylinder 11 houses a piston. In each cylinder 11, the piston is capable of reciprocating. The piston is connected to the crankshaft 31 via a connecting rod. The crankshaft 31 rotates in response to the reciprocating motion of the piston.

[0016] The engine body 10A has a water jacket 18. The water jacket 18 is a passage through which cooling water flows. The water jacket 18 is positioned around the multiple cylinders 11.

[0017] The internal combustion engine 10 has a plurality of spark plugs 19. One spark plug 19 is provided for each cylinder 11. The tip of the spark plug 19 is located inside the cylinder 11. The spark plug 19 ignites an air-fuel mixture of intake air and fuel. As a result, the air-fuel mixture is burned inside the cylinder 11.

[0018] The internal combustion engine 10 has an intake passage 15, a throttle valve 16, and multiple fuel injection valves 17. The intake passage 15 is a passage for introducing intake air into each cylinder 11. The intake passage 15 is connected to each cylinder 11. The throttle valve 16 is located midway through the intake passage 15. The throttle valve 16 adjusts the amount of intake air GA flowing into the intake passage 15. The multiple fuel injection valves 17 are located downstream of the throttle valve 16 in the intake passage 15. The fuel injection valve 17 is provided for each cylinder 11. The fuel injection valve 17 injects fuel to supply the fuel into the cylinder 11.

[0019] The internal combustion engine 10 has an exhaust passage 21, a three-way catalyst 22, and a gasoline particulate filter (hereinafter referred to as GPF) 23. The exhaust passage 21 is a passage for discharging exhaust gas from each cylinder 11. The exhaust passage 21 is connected to each cylinder 11. The three-way catalyst 22 is located midway through the exhaust passage 21. The three-way catalyst 22 purifies the exhaust gas. The three-way catalyst 22 has an oxygen storage capacity. The GPF 23 is located downstream of the three-way catalyst 22 in the exhaust passage 21. The GPF 23 collects particulate matter (hereinafter referred to as PM) contained in the exhaust gas.

[0020] The internal combustion engine 10 has an air flow meter 61, a first temperature sensor 62, a second temperature sensor 63, and a crank angle sensor 64. The air flow meter 61 is located upstream of the throttle valve 16 in the intake passage 15. The air flow meter 61 detects the amount of intake air GA flowing into the intake passage 15. The first temperature sensor 62 is located near the GPF 23. The first temperature sensor 62 detects the temperature TF of the GPF 23. The second temperature sensor 63 is located at the outlet of the water jacket 18. The second temperature sensor 63 detects the temperature TW of the cooling water. The crank angle sensor 64 is located near the crankshaft 31. The crank angle sensor 64 detects the rotational position CR of the crankshaft 31.

[0021] The vehicle 500 has an automatic transmission 50. The automatic transmission 50 has an input shaft 52, an output shaft 54, a transmission mechanism 56, and a hydraulic circuit 55. The input shaft 52 is connected to the crankshaft 31. The output shaft 54 ​​is connected to the drive wheels 60 via a differential or the like. The transmission mechanism 56 is interposed between the input shaft 52 and the output shaft 54. The transmission mechanism 56 has a plurality of engagement elements 58, a plurality of planetary gear mechanisms 57, and a lock mechanism 59. In FIG. 1, the plurality of engagement elements 58 are all shown as one square. The same is true for the plurality of planetary gear mechanisms 57. Each engagement element 58 is either a clutch or a brake. The engagement and disengagement states of each engagement element 58 are switched according to the hydraulic pressure of the hydraulic circuit 55. According to the engagement and disengagement states of each engagement element 58, the transmission mechanism 56 can form a plurality of gear stages. Specifically, the transmission mechanism 56 can form a gear for forward travel and a gear for reverse travel. When these gears are formed, the transmission mechanism 56 reduces the rotation of the input shaft 52 and transmits it to the output shaft 54. In addition to the above-mentioned gears, the transmission mechanism 56 can form a gear (hereinafter, referred to as a cut-off gear) that cuts off the power transmission between the input shaft 52 and the output shaft 54. In other words, when the transmission mechanism 56 forms the cut-off gear, the transmission mechanism 56 does not transmit torque from the input shaft 52 to the output shaft 54. The lock mechanism 59 locks the output shaft 54 ​​so that it cannot rotate, or allows the output shaft 54 ​​to rotate.

[0022] The transmission mechanism 56 switches to one of four shift ranges according to a combination of the above-mentioned multiple gears and whether the output shaft 54 ​​is locked. The four shift ranges are a drive range, a reverse range, a neutral range, and a parking range. The drive range is established when the transmission mechanism 56 is in a forward gear and allows the output shaft 54 ​​to rotate. The reverse range is established when the transmission mechanism 56 is in a reverse gear and allows the output shaft 54 ​​to rotate. The neutral range is established when the transmission mechanism 56 is in a cut-off gear and allows the output shaft 54 ​​to rotate. The parking range is established when the transmission mechanism 56 is in a cut-off gear and locks the output shaft 54 ​​from rotating.

[0023] The vehicle 500 has a shift lever 82. The shift lever 82 is located within the passenger compartment of the vehicle 500. The shift lever 82 is a lever that can be switched by an occupant to one of four predetermined operating positions. Each operating position corresponds to a different shift range in the automatic transmission 50.

[0024] The vehicle 500 has a shift position sensor 84, an accelerator sensor 87, a vehicle speed sensor 88, and a GPS receiver 89. The shift position sensor 84 detects the operation position of the shift lever 82 as a lever position LV. The accelerator sensor 87 detects the depression amount of the accelerator pedal in the vehicle 500 as an accelerator operation amount ACC. The vehicle speed sensor 88 detects the traveling speed of the vehicle 500 as a vehicle speed SP. The GPS receiver 89 receives a signal related to the current position coordinate U of the vehicle 500 from a GPS satellite. The position coordinate U is, in detail, a coordinate value of latitude and longitude.

[0025] <Outline of the control device> The vehicle 500 includes a control device 100. The control device 100 may be configured as one or more processors that execute various processes according to a computer program (software). The control device 100 may be configured as one or more dedicated hardware circuits, such as an application specific integrated circuit (ASIC), that execute at least a part of the various processes, or a circuit including a combination thereof. The processor includes a CPU 102 and memories such as a RAM and a ROM 104. The memory stores program codes or instructions that are configured to cause the CPU 102 to execute processes. The memory, i.e., a computer-readable medium, includes any available medium that can be accessed by a general-purpose or dedicated computer. The control device 100 also includes a storage device 106, which is an electrically rewritable non-volatile memory.

[0026] The control device 100 receives detection signals from various sensors attached to the vehicle 500. Specifically, the control device 100 receives detection signals for the following parameters:

[0027] - Intake volume GA detected by air flow meter 61 The temperature TF of the GPF 23 detected by the first temperature sensor 62 The temperature of the cooling water detected by the second temperature sensor 63, TW The rotational position CR of the crankshaft 31 detected by the crank angle sensor 64 Lever position LV detected by shift position sensor 84 Accelerator operation amount ACC detected by accelerator sensor 87 Vehicle speed SP detected by the vehicle speed sensor 88 The control device 100 also receives a signal relating to the current position coordinate U received by the GPS receiver 89 .

[0028] The control device 100 stores map data in advance. The map data has a plurality of nodes and a plurality of links. Each node indicates a position coordinate. Each link is defined as a line segment connecting adjacent nodes. Each link indicates a road. The plurality of nodes and the plurality of links form a road map. The map data also includes information on the altitude of each node.

[0029] The control device 100 controls the automatic transmission 50. The control device 100 switches the shift range of the automatic transmission 50 in accordance with the lever position LV. The control device 100 controls the internal combustion engine 10. The control device 100 controls various parts of the internal combustion engine 10 based on a required torque obtained from the vehicle speed SP and the accelerator operation amount ACC. The control device 100 controls the internal combustion engine 10 to an idle operation state according to the situation. For example, when the shift range of the automatic transmission 50 is the neutral range and the accelerator operation amount ACC is zero, the control device 10 controls the internal combustion engine 10 so that the rotation speed (hereinafter, referred to as the engine rotation speed) NE of the crankshaft 31 becomes a target idle rotation speed. At this time, the control device 100 feedback controls the opening degree of the throttle valve 16 and adjusts the amount of fuel supplied to the cylinder 11 accordingly. The control device 100 stores the target idle rotation speed in advance. Note that when the shift range of the automatic transmission 50 is the neutral range and the accelerator operation amount ACC is greater than zero, the control device 100 controls the internal combustion engine 10 so as to output a torque corresponding to the accelerator operation amount ACC.

[0030] The control device 100 constantly calculates various parameters indicating the operating state of the internal combustion engine 10 based on detection signals received from various sensors. Specifically, the control device 100 calculates the engine speed NE based on the rotational position CR of the crankshaft 31. The control device 100 also calculates the engine load KL based on the engine speed NE and the intake air amount GA. Furthermore, the control device 100 calculates the amount of PM accumulated in the GPF 23 (hereinafter referred to as PM accumulation amount) Z based on the engine load KL and the coolant temperature TW.

[0031] <Fuel cut processing> The control device 100 can execute a fuel cut process as one of a number of processes for controlling the internal combustion engine 10. The fuel cut process is a process for removing PM accumulated in the GPF 23 from the GPF 23. In the fuel cut process, the control device 100 alternately repeats a stop pattern and a combustion pattern while continuing the operation of the internal combustion engine 10. The stop pattern is a pattern in which fuel supply to M consecutive cylinders 11 is stopped in the order of the cylinders 11 that undergo a combustion stroke. The number M of cylinders 11 to which fuel supply is stopped (hereinafter, referred to as stopped cylinders) will be described later. The combustion pattern is a pattern in which fuel is supplied to N consecutive cylinders 11 in the order of the cylinders 11 that undergo a combustion stroke. The number N of cylinders 11 to which fuel is supplied (hereinafter, referred to as combustion cylinders) will be described later. When executing the fuel cut process, the control device 100 stops ignition by the spark plug 19 for the stopped cylinders and performs ignition by the spark plug 19 for the combustion cylinders.

[0032] In this embodiment, the control device 100 can execute two types of fuel cut processing. In the first fuel cut processing, which is one of the fuel cut processing, the number M of stopped cylinders is set to "1" and the number N of combustion cylinders is set to "3". That is, in the first fuel cut processing, the control device 100 stops the fuel supply to one of the four cylinders 11 during one combustion cycle, while supplying fuel to the remaining three. One combustion cycle is a series of processes in which the four cylinders 11 each undergo a combustion stroke once, that is, a period in which the crankshaft 31 rotates twice. In the second fuel cut processing, which is the other fuel cut processing, the number M of stopped cylinders is set to "2" and the number N of combustion cylinders is set to "2". That is, in the second fuel cut processing, the control device 100 stops the fuel supply to two of the four cylinders 11 during one combustion cycle, while supplying fuel to the remaining two. In the following, the above two types of fuel cut processing will be referred to as a first fuel cut processing and a second fuel cut processing when described individually, and will be referred to as a fuel cut processing when described collectively.

[0033] In both the first fuel cut process and the second fuel cut process, the control device 100 supplies fuel to the combustion cylinder so that the air-fuel ratio of the mixture in the combustion cylinder becomes the theoretical air-fuel ratio. Here, a mechanism for removing PM from the GPF 23 through the execution of the fuel cut process will be described. Now, it is assumed that fuel is supplied to the combustion cylinder and ignition is performed by the spark plug 19. In this case, the mixture is burned in the combustion cylinder. Then, the combustion cylinder discharges high-temperature exhaust gas into the exhaust passage 21. On the other hand, the stopped cylinder discharges oxygen into the exhaust passage 21. When the high-temperature exhaust gas discharged by the combustion cylinder and the oxygen discharged by the stopped cylinder reach the GPF 23, the PM accumulated in the GPF 23 is burned. Then, the PM disappears. Through this process, it is possible to remove PM from the GPF 23, that is, to regenerate the GPF 23. In the second fuel cut process, the number M of stopped cylinders increases compared to the first fuel cut. Accordingly, in the second fuel cut process, the amount of oxygen supplied to the GPF 23 per combustion cycle is increased compared to the first process.

[0034] <Outline of the first judgment process> The control device 100 is capable of executing a first determination process. The first determination process is a process for determining whether or not a first start condition, which is a start condition for a first fuel cut process, is satisfied.

[0035] The first starting condition is that all of the following five items are met: (1A) The shift range of the automatic transmission 50 is the neutral range. (1B) The current accelerator operation amount ACC is zero. (1C) The current PM accumulation amount Z is equal to or greater than the initial accumulation amount ZA. (1D) Vehicle 500 is traveling downhill. (1E) After this, the downhill road continues for a distance equal to or greater than the judgment distance L. (1F) The first temperature T1 is equal to or lower than the set temperature TA.

[0036] The contents of each variable defining the first start condition will be explained. The initial accumulation amount ZA is determined in advance, for example, by experiment or simulation, as a value at which the PM accumulation amount Z in the GPF 23 is appropriately large and it is desired to remove PM from the GPF 23. The control device 100 stores the initial accumulation amount ZA in advance.

[0037] The judgment distance L is determined by experiment or simulation as a traveling distance at which a reasonable amount of PM can be expected to be removed in the GPF 23 when the first fuel cut process is performed. The control device 100 stores the judgment distance L in advance.

[0038] The first temperature T1 is an estimated temperature of the GPF 23 when it is assumed that the current PM accumulation amount Z has been reduced to the end accumulation amount ZB by performing the first fuel cut process. The set temperature TA is determined in advance, for example, by experiment or simulation, as the maximum temperature TF of the GPF 23 that is allowable for preventing damage to the GPF 23. Damage to the GPF 23 means, for example, melting of the GPF 23. The control device 100 stores the set temperature TA in advance. The end accumulation amount ZB is determined in advance, for example, by experiment or simulation, as a value at which the PM accumulation amount Z becomes sufficiently small and the PM removal process may be terminated. The end accumulation amount ZB is smaller than the start accumulation amount ZA. The control device 100 stores the end accumulation amount ZB in advance.

[0039] The first temperature T1 varies depending on the current PM accumulation amount Z and the current temperature TF of the GPF 23. For example, if the difference between the current PM accumulation amount Z and the final accumulation amount ZB is large, the temperature rise of the GPF 23 increases as a result of burning a large amount of PM. In addition, even if the temperature rise is the same, if the temperature TF of the current GPF 23, which is the initial temperature, is high, the first temperature T1, which is the final temperature, is also high. Therefore, in this embodiment, the control device 100 calculates the first temperature T1 based on the first temperature rise amount ΔT1 and the current temperature TF of the GPF 23. The first temperature rise amount ΔT1 is the temperature rise amount of the GPF 23 when it is assumed that the current PM accumulation amount Z is reduced to the final accumulation amount ZB by performing the first fuel cut process. The control device 100 calculates the first temperature T1 by adding the current temperature TF of the GPF 23 to the first temperature rise amount ΔT1. The process of calculating the first temperature T1 is a first estimation process.

[0040] The control device 100 stores a first temperature rise map in advance as information for calculating the first temperature rise amount ΔT1. The first temperature rise map represents the relationship between the amount of PM reduction in the GPF 23 and the temperature rise amount of the GPF 23 when the first fuel cut process is performed. The above-mentioned first temperature rise map reflects the temperature rise amount of the GPF 23 according to the amount of oxygen in the total gas supplied to the GPF 23 when the first fuel cut process is performed. The first temperature rise map is created based on, for example, an experiment or a simulation.

[0041] <Outline of the second judgment process> The control device 100 is capable of executing a second determination process. The second determination process is a process for determining whether or not a second start condition, which is a start condition for the second fuel cut process, is satisfied. The control device 100 performs the second determination process while the first fuel cut process is being executed. In other words, the second determination process is a process for determining whether or not it is possible to switch from the first fuel cut process to the second fuel cut process.

[0042] The second start condition is that the following two items are both true: (2A) PM accumulation amount Z is less than or equal to the set accumulation amount ZC. (2B) The second temperature T2 is equal to or lower than the set temperature TA.

[0043] The contents of each variable defining the second start condition will be explained below. First, the set accumulation amount ZC will be described. As a premise, the GPF 23 is cylindrical as a whole. When the GPF 23 is disposed in the exhaust passage 21, the central axis of the GPF 23 extends so as to be generally along the direction in which the exhaust gas flows. The GPF 23 has an accumulation concentration point 23a where PM is likely to accumulate. Specifically, the accumulation concentration point 23a is an upstream portion of the GPF 23 and a radially inner portion. In FIG. 1, the accumulation of PM in the GPF 23 is shown diagrammatically by the density of dots. In FIG. 1, the accumulation concentration point 23a is an area with a high dot density. When the total amount of PM accumulation amount Z in the GPF 23 is large, the PM accumulation amount Z at the accumulation concentration point 23a becomes considerably large. As described above, the amount of oxygen supplied to the GPF 23 is larger in the second fuel cut process than in the first fuel cut process. If a large amount of oxygen is supplied to the deposition concentration point 23a under the condition that a large amount of PM is deposited at the deposition concentration point 23a, the deposition concentration point 23a locally becomes hot due to the combustion of the PM at the deposition concentration point 23a. This may cause the GPF 23 to enter an abnormal heat generation state. The set deposition amount ZC is determined in advance, for example, by experiment or simulation, as the maximum value of the PM deposition amount Z at which the GPF 23 does not enter an abnormal heat generation state even when the second fuel cut is performed. The set deposition amount ZC is, for example, 20% of the initial deposition amount ZA. The control device 100 stores the set deposition amount ZC in advance.

[0044] Next, the second temperature T2 will be described. The second temperature T2 is an estimated temperature of the GPF 23 when it is assumed that the current PM accumulation amount Z is reduced to the final accumulation amount ZB by performing the second fuel cut process. The second temperature T2 varies depending on the current PM accumulation amount Z and the current temperature TF of the GPF 23, similar to the above-mentioned first temperature T1. Therefore, the control device 100 calculates the second temperature T2 based on the second temperature increase amount ΔT2 and the current temperature TF of the GPF 23. The second temperature increase amount ΔT2 is the temperature increase amount of the GPF 23 when it is assumed that the current PM accumulation amount Z is reduced to the final accumulation amount ZB by performing the second fuel cut process. The control device 100 calculates the second temperature T2 by adding this second temperature increase amount ΔT2 to the current temperature TF of the GPF 23. The process of calculating the second temperature T2 is the second estimation process.

[0045] The control device 100 stores a second temperature rise map in advance as information for calculating the second temperature rise amount ΔT2. The second temperature rise map represents the relationship between the amount of decrease in the PM accumulation amount Z and the temperature rise amount of the GPF 23 when the second fuel cut process is performed. The second temperature rise map reflects the temperature rise amount of the GPF 23 according to the amount of oxygen in the total gas supplied to the GPF 23 when the second fuel cut process is performed. Here, when the amount of oxygen supplied to the GPF 23 is large, the GPF 23 becomes an environment in which PM is more likely to burn than when it is small. Therefore, in the former case, the combustion of PM in the GPF 23 is promoted compared to the latter case. And more PM is burned. As a result, in the former case, the temperature rise amount of the GPF 23 is larger compared to the latter case. Reflecting this, there are the following differences between the second temperature rise map and the first temperature rise map. That is, when the decrease in the PM accumulation amount Z is the first value, the temperature rise amount of the GPF 23 in the second temperature rise map is larger than the temperature rise amount of the GPF 23 in the first temperature rise map. Note that the second temperature rise map is created based on, for example, an experiment or a simulation.

[0046] <About the end judgment process> The control device 100 is capable of executing an end determination process. The end determination process is a process for determining whether or not an end condition for the fuel cut process currently being executed is satisfied. The fuel cut process currently being executed may be either the first fuel cut process or the second fuel cut process. In this embodiment, the same end condition is set for both the first fuel cut process and the second fuel cut process.

[0047] The termination condition is that at least one of the following items is met: (3A) The shift range of the automatic transmission 50 is other than the neutral range. (3B) The current accelerator operation amount ACC is greater than zero. (3C) The end of the downhill section has been reached. (3D) The current temperature TF of GPF23 is greater than the judgment temperature TB. (3E) The current PM accumulation amount Z is equal to or less than the final accumulation amount ZB.

[0048] The contents of each variable that specifies the termination condition will be explained below. The final accumulation amount ZB is as already described in relation to the first determination process. The control device 100 stores the final accumulation amount ZB in advance.

[0049] The judgment temperature TB is a value as follows. As described above, the item (1F) of the first start condition relates to an estimated value of the temperature TF of the GPF 23 when it is assumed that the first fuel cut process is performed. Since this item is included, the control device 100 starts the first fuel cut process in a situation where it is expected that the GPF 23 will not overheat even if the first fuel cut process is performed. On the other hand, when the fuel cut process is actually performed to burn PM, for example, due to an error in the amount of oxygen supplied to the GPF 23, a temperature rise exceeding the temperature rise amount of the GPF 23 specified in the first temperature rise map may occur. The same can be said about the second fuel cut process. The above item (3D) is a requirement for avoiding such an overheating of the GPF 23 during the process of actually burning PM. The judgment temperature TB is determined in advance, for example, by an experiment or a simulation, as the maximum value of the temperature TF of the GPF 23 that is allowed to prevent damage to the GPF 23 under a situation where the fuel cut process is actually performed. The control device 100 stores the judgment temperature TB in advance.

[0050] <Specific Processing Procedure of the First Determination Process> The control device 100 repeatedly executes the first determination process while the internal combustion engine 10 is in operation and neither the first fuel cut process nor the second fuel cut process is being executed.

[0051] As shown in FIG. 2, when the control device 100 starts the first determination process, it first executes the process of step S110. In step S110, the control device 100 determines whether the shift range of the automatic transmission 50 is the neutral range. The control device 100 makes this determination by referring to the control content related to the automatic transmission 50. If the shift range of the automatic transmission 50 is not the neutral range (step S110: NO), the control device 100 temporarily ends the series of steps of the first determination process. In this case, the control device 100 executes the process of step S110 again.

[0052] On the other hand, in step S110, if the shift range of the automatic transmission 50 is the neutral range (step S110: YES), the control device 100 proceeds to step S120. The process of step S110 is a process for determining whether or not the first start condition item (1A) is satisfied.

[0053] In step S120, the control device 100 judges whether the current accelerator operation amount ACC is zero. Specifically, the control device 100 refers to the latest accelerator operation amount ACC. If the latest accelerator operation amount ACC is greater than zero (step S120: NO), the control device 100 temporarily ends the series of processes in the first judgment process. Then, the control device 100 executes the process of step S110 again.

[0054] On the other hand, in step S120, if the latest accelerator operation amount ACC is zero (step S120: YES), the control device 100 advances the process to step S130. The process of step S120 is a process for determining whether or not the item (1B) of the first start condition is satisfied.

[0055] In step S130, the control device 100 judges whether the current PM accumulation amount Z is equal to or greater than the start accumulation amount ZA. Specifically, the control device 100 refers to the latest PM accumulation amount Z and the start accumulation amount ZA. Then, the control device 100 compares the magnitude of these values. If the latest PM accumulation amount Z is less than the start accumulation amount ZA (step S130: NO), the control device 100 temporarily ends the series of processes in the first judgment process. Then, the control device 100 executes the process of step S130 again.

[0056] On the other hand, in step S130, if the latest PM accumulation amount Z is equal to or greater than the start accumulation amount ZA (step S130: YES), the control device 100 proceeds to step S140. The process of step S130 is a process for determining whether or not the item (1C) of the first start condition is satisfied.

[0057] In step S140, the control device 100 determines whether the vehicle 500 is traveling. Specifically, the control device 100 refers to the latest vehicle speed SP. If the vehicle speed SP is zero, the control device 100 determines that the vehicle 500 is stopped (step S140: NO). In this case, the control device 100 temporarily ends the series of processes in the first determination process. Then, the control device 100 executes the process of step S110 again.

[0058] On the other hand, in step S140, when the vehicle speed SP is greater than zero, the control device 100 determines that the vehicle 500 is traveling (step S140: YES). In this case, the control device 100 advances the process to step S150. The processes of step S140 and step S150 described below are processes for determining whether or not the item (1D) of the first start condition is satisfied.

[0059] In step S150, the control device 100 judges whether the road on which the vehicle 500 is traveling is a downhill road. Specifically, the control device 100 refers to the map data, the latest position coordinate U, and the position coordinate U received at the previous timing. Then, the control device 100 specifies the current position of the vehicle 500 in the road map in the map data based on the latest position coordinate U. After that, the control device 100 grasps the road surface gradient of the link on which the vehicle 500 is currently located based on the altitude information included in the map data. Note that, in the map data of this embodiment, for example, when an uphill road and a downhill road are alternately continued, one link represents the lowest point to the highest point of the uphill road, and one link represents the highest point to the lowest point of the downhill road. In other words, the map data represents the highest point to the lowest point of a continuous slope road with one link. And the nodes at both ends of the link representing the slope road are the highest point and the lowest point of the slope road.

[0060] Now, when determining the road surface gradient of the link on which the vehicle 500 is currently located, the control device 100 refers to the difference in altitude between the nodes at both ends of the link. If the road surface gradient of the link on which the vehicle 500 is currently located is within a range that can be considered to be zero, the control device 100 determines that the link on which the vehicle 500 is traveling is not a slope (step S150: NO). In this case, the control device 100 temporarily ends the series of processes of the first determination process. In this case, the control device 100 executes the process of step S110 again.

[0061] On the other hand, when the road surface gradient of the link on which the vehicle 500 is currently located is greater than a value that can be regarded as zero, the control device 100 determines that the link on which the vehicle 500 is traveling is a slope. In this case, the control device 100 identifies the traveling direction of the vehicle 500 based on the latest position coordinate U and the position coordinate U at the previous timing. Then, the control device 100 determines whether the vehicle 500 is traveling from a high altitude side to a low altitude side. When the vehicle 500 is traveling from a low altitude side to a high altitude side, the control device 100 determines that the link on which the vehicle 500 is traveling is an uphill road (step S150: NO). In this case, the control device 100 temporarily ends a series of processes of the first determination process. Then, the control device 100 executes the process of step S110 again. On the other hand, when the vehicle 500 is traveling from a high altitude side to a low altitude side, the control device 100 determines that the link on which the vehicle 500 is traveling is a downhill road (step S150: YES). In this case, the control device 100 advances the process to step S160.

[0062] In step S160, the control device 100 judges whether the downhill road continues for the judgment distance L or more. The control device 100 performs the process of step S160 by referring to the map data and the information specified in step S150. Specifically, the control device 100 refers to the current position of the vehicle 500 on the road map and the link on which the vehicle 500 is currently traveling. Then, the control device 100 calculates an estimated distance, which is the length of the path from the current position of the vehicle 500 to a node on the link on which the vehicle 500 is currently traveling in the traveling direction of the vehicle 500. Then, the control device 100 refers to the judgment distance L. Then, the control device 100 compares the estimated distance with the judgment distance L. If the estimated distance is less than the judgment distance L, the control device 100 judges that the downhill road does not continue for the judgment distance L or more (step S160: NO). In this case, the control device 100 temporarily ends the series of processes of the first judgment process. In this case, the control device 100 executes the process of step S110 again.

[0063] On the other hand, in step S160, if the estimated distance is equal to or longer than the judgment distance L, the control device 100 determines that the downhill road will continue for equal to or longer than the judgment distance L (step S160: YES). In this case, the control device 100 advances the process to step S170. The process of step S160 is a process for determining whether or not the item (1E) of the first start condition is satisfied.

[0064] In step S170, the control device 100 calculates the first temperature rise amount ΔT1. As described above, the first temperature rise amount ΔT1 is the temperature rise amount of the GPF 23 when it is assumed that the current PM accumulation amount Z is reduced to the final accumulation amount ZB by performing the first fuel cut process. As a specific process in step S170, the control device 100 refers to the latest PM accumulation amount Z and the final accumulation amount ZB. Then, the control device 100 calculates a first difference value ΔZ1 obtained by subtracting the final accumulation amount ZB from the latest PM accumulation amount Z. Next, the control device 100 refers to the first temperature rise map. Then, the control device 100 calculates the temperature rise amount of the GPF 23 corresponding to the first difference value ΔZ1 based on the first temperature rise map. After this, the control device 100 advances the process to step S180.

[0065] In step S180, the control device 100 calculates the first temperature T1. As described above, the first temperature T1 is an estimated temperature of the GPF 23 when it is assumed that the current PM accumulation amount Z has been reduced to the final accumulation amount ZB by performing the first fuel cut process. As a specific process in step S180, the control device 100 refers to the latest temperature TF of the GPF 23 and the first temperature rise amount ΔT1 calculated in step S170. Then, the control device 100 calculates the first temperature T1 by adding these values. After this, the control device 100 proceeds to the process in step S190. The processes in steps S170 and S180 are the first estimation process.

[0066] In step S190, the control device 100 judges whether the first temperature T1 is equal to or lower than the set temperature TA. Specifically, the control device 100 refers to the first temperature T1 calculated in step S180 and the set temperature TA. Then, the control device 100 compares these temperatures. If the first temperature T1 is higher than the set temperature TA (step S190: NO), the control device 100 temporarily ends the series of steps in the first judgment process. In this case, the control device 100 executes the process of step S110 again.

[0067] On the other hand, in step S190, if the first temperature T1 is equal to or lower than the set temperature TA (step S190: YES), the control device 100 advances the process to step S200. The process of step S190 is a process for determining whether or not the item (1F) of the first start condition is satisfied.

[0068] In step S200, the control device 100 starts the first fuel cut process. In this case, the control device 100 ends the series of processes of the first determination process. Note that, when the first determination process is ended through the process of step S200, the execution condition of the first determination process, that is, neither the first fuel cut process nor the second fuel cut process is being executed, is not satisfied. Therefore, in this case, the control device 100 waits for execution of the first determination process until a state in which neither the first fuel cut process nor the second fuel cut process is being executed is reached. That is, the control device 100 waits for execution of the first determination process until the first fuel cut process or the second fuel cut process is ended by executing step S480 of the end determination process described later. Then, when the control device 100 executes step S480 in the end determination process, it resumes the first determination process. Note that, when the ignition switch of the vehicle 500 is turned off during the execution of the above-mentioned first determination process, the control device 100 ends the first determination process at that point.

[0069] <Specific Processing Procedure of the Second Determination Process> When the control device 100 starts the first fuel cut process, it starts the second determination process. The control device 100 repeatedly executes the second determination process while the first fuel cut process is being executed.

[0070] As shown in FIG. 3, when the control device 100 starts the second determination process, it first executes the process of step S310. In step S310, the control device 100 determines whether the current PM deposition amount Z is equal to or less than the set deposition amount ZC. Specifically, the control device 100 refers to the latest PM deposition amount Z and the set deposition amount ZC. Then, the control device 100 compares these amounts. If the latest PM deposition amount Z is greater than the set deposition amount ZC (step S310: NO), the control device 100 temporarily ends the series of steps of the second determination process. In this case, the control device 100 executes the process of step S310 again.

[0071] On the other hand, in step S310, if the PM accumulation amount Z is equal to or less than the set accumulation amount ZC (step S310: YES), the control device 100 proceeds to step S320. This is a situation in which the PM accumulation amount Z has decreased to or less than the set accumulation amount ZC due to the first fuel cut process before it is determined to end the first fuel cut process by the end determination process described below. Note that the process of step S310 is for determining whether or not the item (2A) of the second start condition is satisfied.

[0072] In step S320, the control device 100 calculates the second temperature rise amount ΔT2. As described above, the second temperature rise amount ΔT2 is the temperature rise amount of the GPF 23 when it is assumed that the current PM deposition amount Z is reduced to the final deposition amount ZB by performing the second fuel cut process. As a specific process in step S320, the control device 100 refers to the latest PM deposition amount Z and the final deposition amount ZB. Then, the control device 100 calculates a second difference value ΔZ2 obtained by subtracting the final deposition amount ZB from the latest PM deposition amount Z. Next, the control device 100 refers to the second temperature rise map. Then, the control device 100 calculates the temperature rise amount of the GPF 23 corresponding to the second difference value ΔZ2 based on the second temperature rise map. After this, the control device 100 advances the process to step S330.

[0073] In step S330, the control device 100 calculates the second temperature T2. As described above, the second temperature T2 is an estimated temperature of the GPF 23 when it is assumed that the current PM accumulation amount Z has been reduced to the final accumulation amount ZB by performing the second fuel cut process. As a specific process in step S330, the control device 100 refers to the latest temperature TF of the GPF 23 and the second temperature rise amount ΔT2 calculated in step S320. Then, the control device 100 calculates the second temperature T2 by adding these values. After this, the control device 100 proceeds to the process in step S340. The processes in steps S320 and S330 are second estimation processes.

[0074] In step S340, the control device 100 determines whether the second temperature T2 is equal to or lower than the set temperature TA. Specifically, the control device 100 refers to the second temperature T2 calculated in step S330 and the set temperature TA. Then, the control device 100 compares these temperatures. If the second temperature T2 is higher than the set temperature TA (step S340: NO), the control device 100 temporarily ends the series of steps in the second determination process. In this case, the control device 100 executes the process of step S310 again.

[0075] On the other hand, in step S340, if the second temperature T2 is equal to or lower than the set temperature TAZC (step S340: YES), the control device 100 proceeds to step S350. This is a situation in which the second temperature T2 has decreased to or lower than the set temperature TA as a result of the first fuel cut process before the end determination process determines that the first fuel cut process is to be ended. The process of step S340 is for determining whether or not the item (2B) of the second start condition is satisfied.

[0076] In step S350, the control device 100 ends the first fuel cut process and starts the second fuel cut process. After this, the control device 100 ends the series of processes of the second determination process. Note that, if the second determination process is ended through the process of step S350, the execution condition of the second determination process, that is, the first fuel cut process is being executed, is not satisfied. Therefore, in this case, the control device 100 waits to execute the second determination process until the first fuel cut process is next started. Note that, similarly to the case of the first determination process, if the ignition switch of the vehicle 500 is turned off during the execution of the second determination process, the control device 100 ends the second determination process at that point.

[0077] <Specific processing procedure for end determination processing> When the control device 100 is executing the first fuel cut processing or the second fuel cut processing, the control device 100 repeatedly executes an end determination processing in parallel with these fuel cut processing.

[0078] As shown in Fig. 4, when the control device 100 starts the end determination process, it first executes the process of step S410. In step S410, the control device 100 determines whether the shift range of the automatic transmission 50 is the neutral range. As with step S110 of the first determination process, the control device 100 makes this determination by referring to the control content related to the automatic transmission 50. If the shift range of the automatic transmission 50 is not the neutral range (step S410: NO), the control device 100 advances the process to step S480.

[0079] In step S480, the control device 100 ends the fuel cut process currently being executed. That is, if the first fuel cut process is currently being executed, the control device 100 ends the first fuel cut process. Also, if the second fuel cut process is currently being executed, the control device 100 ends the second fuel cut process. After this, the control device 100 ends the series of processes of the end determination process. Note that, if the end determination process is ended through the process of step S480, a situation occurs in which neither the first fuel cut process nor the second fuel cut process is being executed. In this case, a situation occurs in which the execution condition of the end determination process, that is, the first fuel cut process or the second fuel cut process is being executed, is not satisfied. In this case, the control device 100 waits to execute the end determination process until the first fuel cut process is started next. Also, if the end determination process is ended through the process of step S480, the control device 100 starts the first determination process because the execution condition of the first determination process is satisfied.

[0080] Now, in step S410, if the shift range of the automatic transmission 50 is the neutral range (step S410: YES), the control device 100 proceeds to step S420. The process of step S410 is a process for determining whether or not the end condition item (3A) is satisfied.

[0081] In step S420, the control device 100 judges whether the current accelerator operation amount ACC is zero. Specifically, the control device 100 refers to the latest accelerator operation amount ACC. Then, if the latest accelerator operation amount ACC is greater than zero (step S420: NO), the control device 100 advances the process to step S480. Then, the control device 100 ends the fuel cut process currently being executed.

[0082] On the other hand, in step S420, if the latest accelerator operation amount ACC is zero (step S420: YES), the control device 100 advances the process to step S430. The process of step S420 is a process for determining whether or not the end condition item (3B) is satisfied.

[0083] In step S430, the control device 100 judges whether the vehicle 500 has not yet reached the end point of the downhill road. As a specific process of step S430, the control device 100 refers to the map data, the information identified in step S150, and the latest position coordinate U. Then, the control device 100 identifies the current position of the vehicle 500 in the road map in the map data based on the latest position coordinate U. After that, the control device 100 judges whether the latest position coordinate U matches the position coordinate of the node on the traveling direction side of the link identified in step S150. If the above judgment is positive, the control device 100 judges that the vehicle 500 has reached the end point of the downhill road (step S430: NO). Furthermore, even if the latest position coordinate U is not on the link identified in step S150, the control device 100 judges that the vehicle 500 has reached the end point of the downhill road (step S430: NO). In these cases, the control device 100 advances the process to step S480. Then, the control device 100 ends the fuel cut process currently being executed.

[0084] On the other hand, in step S430, the control device 100 determines that the vehicle 500 has not yet reached the end point of the downhill road in the following case. That is, the latest position coordinate U does not match the position coordinate of the node on the traveling direction side of the link identified in step S150, and the latest position coordinate U is on the link. In this case (step S430: NO), the control device 100 advances the process to step S440. The process of step S430 is a process for determining whether or not the end condition item (3C) is satisfied.

[0085] In step S440, the control device 100 determines whether the current temperature TF of the GPF 23 is equal to or lower than the judgment temperature TB. Specifically, the control device 100 refers to the latest temperature TF of the GPF 23 and the judgment temperature TB. Then, the control device 100 compares these temperatures. If the latest temperature TF of the GPF 23 is greater than the judgment temperature TB (step S440: NO), the control device 100 proceeds to step S480. Then, the control device 100 ends the fuel cut process currently being executed.

[0086] On the other hand, if the latest temperature TF of the GPF 23 is equal to or lower than the judgment temperature TB (step S440: YES), the control device 100 proceeds to step S450. The process of step S440 is a process for determining whether or not the end condition item (3D) is satisfied.

[0087] In step S450, the control device 100 determines whether the current PM accumulation amount Z is greater than the end accumulation amount ZB. Specifically, the control device 100 refers to the latest PM accumulation amount Z and the end accumulation amount ZB. Then, the control device 100 compares these amounts. If the latest PM accumulation amount Z is equal to or less than the end accumulation amount ZB (step S450: NO), the control device 100 advances the process to step S480. Then, the control device 100 ends the fuel cut process currently being executed.

[0088] On the other hand, when the latest PM accumulation amount Z is greater than the end accumulation amount ZB (step S450: YES), the control device 100 temporarily ends the series of processes of the end determination process. In this case, the control device 100 executes the process of step S410 again. The process of step S450 is a process for determining whether or not the end condition item (3E) is satisfied.

[0089] The above is the content of the termination determination process. If the ignition switch of the vehicle 500 is turned off during the execution of the termination determination process, the control device 100 ends the termination determination process at that point in time.

[0090] <Operation of the embodiment> (a) Overall flow of the start and end of each process Now, assume that the ignition switch of the vehicle 500 is turned on and the internal combustion engine 10 is started. Then, the control device 100 starts the first determination process. Then, the control device 100 repeats the first determination process. That is, the control device 100 repeats the determination of whether the first start condition is satisfied. After the internal combustion engine 10 is started, the vehicle 500 starts traveling and the vehicle 500 approaches a downhill road with a relatively long distance. Then, assume that the passenger sets the shift range of the automatic transmission 50 to the neutral range and releases the accelerator pedal. At this time, if the first temperature T1 is equal to or lower than the set temperature TA, the first start condition is satisfied (steps S110 to S160: YES, step S190: YES). If the first start condition is satisfied, the control device 100 starts the first fuel cut process (step S200). At the same time, the control device 100 ends the repeated execution of the first determination process. When the control device 100 starts the fuel cut process, oxygen is supplied to the GPF 23. This causes the PM to be burned in the GPF 23. Then, the PM accumulation amount Z gradually decreases.

[0091] When the control device 100 starts the first fuel cut process, it starts the second determination process and the end determination process. Then, the control device 100 repeats these processes. That is, the control device 100 repeats the determination of whether or not both the second start condition and the end determination condition are satisfied. The flow of the process thereafter differs in the following two cases.

[0092] The first case is a case in which the end condition is satisfied after the start of the first fuel cut process and before the second start condition is satisfied. The first case is, for example, a case in which the occupant switches the shift range of the automatic transmission 50 to a range other than the neutral range at a relatively early stage after the start of the first fuel cut process (step S410: NO). In the first case, the control device 100 ends the first fuel cut process at that point (step S480) and ends the repeated execution of the end determination process. In this case, the control device 100 ends the repeated execution of the second determination process. Also, the control device 100 resumes the first determination process.

[0093] The second case is a case where the second start condition is satisfied after the start of the first fuel cut process and before the end condition is satisfied. The second case is, for example, a case where the occupant does not switch the shift range to the neutral range for a long period of time, and the period during which the end condition is not satisfied continues for a relatively long period of time. During the period during which the end condition is not satisfied, if the PM accumulation amount Z becomes equal to or less than the set accumulation amount ZC due to the first fuel cut process (step S310: YES) and the second temperature T2 becomes equal to or less than the set temperature TA (step S340: YES), the second condition is satisfied. Then, the control device 100 ends the first fuel cut process and starts the second fuel cut process (step S350). At the same time, the control device 100 ends the repeated execution of the second determination process. The control device 100 thereafter repeats the end determination process. After this, the control device 100 continues the second fuel cut process until the end condition is satisfied. Accordingly, the PM accumulation amount Z gradually decreases. Thereafter, when the end condition is met, for example, when the vehicle 500 finishes traveling downhill (step S430: NO) or the PM accumulation amount Z becomes equal to or less than the end accumulation amount ZB (step S450: NO), the control device 100 ends the second fuel cut process (step S480). At the same time, the control device 100 ends the repeated execution of the end determination process. Then, the control device 100 resumes the first determination process.

[0094] (b) Two-stage fuel cut processing In the second case, the control device 100 switches the type of the fuel cut process from the first fuel cut process to the second fuel cut process in the middle of a series of fuel cut processes. In this case, the amount of oxygen supplied to the GPF 23 is changed to remove PM from the GPF 23 in two stages. During the period in which the first fuel cut process is performed, the amount of oxygen supplied to the GPF 23 is appropriately small. In this case, the combustion of PM is difficult to proceed in the GPF 23 as a whole because the amount of oxygen supplied is small. On the other hand, because the amount of oxygen supplied is small, PM is burned moderately in the deposition concentration point 23a. That is, once PM starts to burn in the deposition concentration point 23a, the combustion area will expand if there is a certain amount of oxygen supplied. At this time, because the amount of oxygen supplied is not so large, the combustion of PM proceeds in the deposition concentration point 23a without causing an abnormal heat generation state.

[0095] When the PM accumulation amount Z at the accumulation concentration point 23a gradually decreases, the second start condition is eventually satisfied. Then, the control device 100 starts the second fuel cut process, which is the second stage. During the period in which the second fuel cut process is being performed, the amount of oxygen supplied to the GPF 23 increases. In this case, PM combustion progresses throughout the GPF 23. That is, PM is also burned in the radially outer parts of the GPF 23 and the downstream parts of the GPF 23, which are parts other than the accumulation concentration point 23a. As a result, PM is quickly eliminated throughout the GPF 23.

[0096] <Effects of the embodiment> (1) When the automatic transmission 50 is in the neutral range and the internal combustion engine 10 is in an idling state while traveling on a downhill road, there are few restrictions on the output of the internal combustion engine 10 while the vehicle 500 is traveling. The control device 100 performs the fuel cut process under such a situation where there is a reasonable degree of freedom in the control of the internal combustion engine 10. At that time, the control device 100 calculates the first temperature T1 as a future estimated temperature of the temperature TF of the GPF 23 in the case where the first fuel cut process is performed, based on the current PM accumulation amount Z and the current temperature TF of the GPF 23. Then, the control device 100 performs the first fuel cut process under the condition that the first temperature T1 is equal to or lower than the set temperature TA. As a result, the control device 100 performs the first fuel cut process only when the GPF 23 does not overheat even if the first fuel cut process is performed, among the situations where there is a reasonable degree of freedom in the control of the internal combustion engine 10. This allows PM to be removed from GPF23 without damaging GPF23.

[0097] (2) When the second fuel cut process is performed, a larger amount of oxygen is supplied to the GPF 23 than when the first fuel cut process is performed. Therefore, in terms of promoting the combustion of PM in the GPF 23, the second fuel cut process is more advantageous than the first fuel cut process. On the other hand, supplying a large amount of oxygen to the GPF 23 may cause the following problem. That is, the total amount of PM accumulation amount Z may be large, and a large amount of PM may accumulate at the accumulation concentration point 23a. In this situation, if a large amount of oxygen is supplied to the GPF 23, the GPF 23 may enter an abnormal heat generation state.

[0098] Therefore, the control device 100 performs the second fuel cut process on the condition that the PM accumulation amount Z is equal to or less than the set accumulation amount ZC. In other words, the control device 100 performs the second fuel cut process only when the GPF 23 will not fall into an abnormal heat generation state even if the second fuel cut process is performed.

[0099] Furthermore, the control device 100 calculates a second temperature T2 as an estimated future temperature of the temperature TF of the GPF 23 in the case where the second fuel cut process is performed, based on the current PM accumulation amount Z and the current temperature TF of the GPF 23. Then, the control device 100 performs the second fuel cut process on the condition that the second temperature T2 is equal to or lower than the set temperature TA. In other words, the control device 100 performs the second fuel cut process only when the temperature of the GPF 23 does not rise excessively even if the second fuel cut process is performed.

[0100] In this way, by performing the second fuel cut process only under circumstances where the GPF 23 is not abnormally heated or overheating and increasing the amount of oxygen supplied to the GPF 23, it is possible to promote the removal of PM without damaging the GPF 23.

[0101] (3) In this embodiment, the control device 100 switches the number M of stopped cylinders in a series of fuel cut processes during the fuel cut process. As a result, the control device 100 changes the amount of oxygen supplied to the GPF 23 during the series of fuel cut processes. That is, the control device 100 keeps the number of stopped cylinders to a minimum in the early stage of starting the removal of the GPF 23. As a result, the control device 100 reduces the amount of oxygen supplied to the GPF 23. This small supply of oxygen allows the PM in the deposition concentration area 23a to be burned appropriately. On the other hand, when the PM in the deposition concentration area 23a is reduced to a certain extent, the control device 100 increases the number of stopped cylinders. As a result, the amount of oxygen supplied to the GPF 23 increases. Accordingly, the combustion of PM in the entire GPF 23 is promoted. If the combustion of PM is progressed in this manner, the GPF 23 will not be in an abnormal heat generation state from the start to the end of the series of fuel cut processes. Moreover, after the amount of PM at the deposition concentration area 23a has decreased to a certain extent, the increase in the amount of oxygen allows the PM to be quickly removed from the entire GPF 23. Therefore, in this embodiment, the PM can be removed from the GPF 23 efficiently without damaging the GPF 23.

[0102] <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.

[0103] The first start condition is not limited to the example of the above embodiment. The first start condition only needs to include the content that all of the items (1A), (1D), and (1F) are satisfied. As long as the first start condition includes this content, the number of items defining the first start condition and the contents of the items may be changed from those in the above embodiment. When an item other than the above three items is included in the first start condition, the contents of the item only need to be appropriate for starting the first fuel cut process.

[0104] Regarding the first start condition, for example, item (1B) in the above embodiment may be omitted. When the shift range of the automatic transmission 50 is the neutral range, the crankshaft 31 and the drive wheels 60 are in a state of being separated from each other. In this case, the output of the internal combustion engine 10 does not become a driving force for running the vehicle 500. Therefore, when the shift range of the automatic transmission 50 is the neutral range, there are few constraints on the output of the internal combustion engine 10 from the viewpoint of running the vehicle 500, regardless of the magnitude of the accelerator operation amount ACC. In other words, not only when the accelerator operation amount ACC is zero, but also when the accelerator operation amount ACC is greater than zero, there is a corresponding degree of freedom in the control of the internal combustion engine 10 as long as the shift range of the automatic transmission 50 is the neutral range. Under such circumstances, it is permitted to perform the first fuel cut process.

[0105] Regarding the first start condition, for example, item (1C) in the above embodiment may be omitted. In other words, the first fuel cut process may be performed to remove PM when the PM accumulation amount Z is not so large. If PM is removed when the PM accumulation amount Z is not so large, the PM accumulation amount Z can be maintained at a low level.

[0106] Regarding the first start condition, for example, item (1E) in the above embodiment may be omitted. Here, when the vehicle 500 approaches a downhill road and the occupant switches the shift range of the automatic transmission 50 to the neutral range, the occupant is likely to know in advance that a fairly long downhill road will follow. Therefore, if items (1A) and (1D) are satisfied, item (1E) is likely to be satisfied.

[0107] Regarding item (1E) of the above embodiment, the method of determining the judgment distance L is not limited to the example of the above embodiment. Even if the judgment distance L is considerably short, by performing the first fuel cut process, it is possible to remove a considerable amount of PM.

[0108] The second start condition is not limited to the example of the above embodiment. The second start condition only needs to include the content that both items (2A) and (2B) described in the above embodiment are satisfied. As long as it includes this content, the number of items defining the second start condition and the contents of the items may be changed from those in the above embodiment. When an item other than the above two items is included in the second start condition, the content of that item only needs to be appropriate for starting the second fuel cut process.

[0109] Regarding item (2A) of the above embodiment, the method of determining the set deposition amount ZC is not limited to the example of the above embodiment. The set deposition amount ZC may be determined from the viewpoint of suppressing abnormal heat generation of the GPF 23. For example, the set deposition amount ZC may be smaller than the maximum value of the PM deposition amount Z at which the GPF 23 does not become abnormally heated.

[0110] The termination conditions are not limited to the examples of the above embodiment. The termination conditions may be any conditions that can terminate the fuel cut process at an appropriate timing on the premise that the running state of the vehicle 500 is maintained in a good condition. For example, from the same viewpoint as the modified example of the above item (1B), item (3B) may be omitted from the termination conditions. That is, the fuel cut process may be continued when the accelerator operation amount ACC is greater than zero. Also, item (3C) may be omitted from the termination conditions. That is, the fuel cut process may be continued after the end point of the downhill road is reached. As long as the shift range of the automatic transmission 50 is in the neutral range, the crankshaft 31 and the drive wheels 60 are in a disconnected state. At this time, there is a corresponding degree of freedom in the control of the internal combustion engine 10. Therefore, even after the end point of the downhill road is reached, for example, if the shift range of the automatic transmission 50 is in the neutral range, the fuel cut process is allowed to be continued.

[0111] The end conditions for the first fuel cut process and the second fuel cut process may be different. The method of calculating the first temperature T1 is not limited to the example of the above embodiment. As long as it is possible to calculate an estimated temperature of the GPF 23 when it is assumed that the current PM accumulation amount Z is reduced to the final accumulation amount ZB by performing the first fuel cut process, the method of calculating the first temperature T1 is not important. In calculating the first temperature T1, for example, a map showing the relationship between the PM accumulation amount Z and the first temperature T1 may be created in advance. Then, the first temperature T1 according to the current PM accumulation amount Z may be calculated based on the map. For example, if the temperature TF of the GPF 23 before the start of the first fuel cut process can be grasped to some extent, it is also possible to create the map as described above.

[0112] The method of calculating the second temperature T2 is not limited to the example of the above embodiment. As long as it is possible to calculate an estimated temperature of the GPF 23 when it is assumed that the current PM accumulation amount Z is reduced to the final accumulation amount ZB by performing the second fuel cut process, the method of calculating the second temperature T2 is not important. As in the above modification of the first temperature T1, a map showing the relationship between the PM accumulation amount Z and the second temperature T2 may be created in advance.

[0113] The number M of stopped cylinders may be switched multiple times during a series of fuel cuts. The number M of stopped cylinders may be increased to three or more in response to such switching. That is, the number of types of fuel cut processes may be three or more. When switching the number M of stopped cylinders, the number M of stopped cylinders before and after the switching may not be consecutive. If the GPF 23 is not damaged even if the amount of oxygen supplied to the GPF 23 increases in response to an increase in the number M of stopped cylinders, a mode in which the number M of stopped cylinders is switched multiple times in this manner is also possible. As in the above embodiment, if the future temperature of the GPF 23 when the number M of stopped cylinders is increased is estimated in advance, the number M of stopped cylinders can be increased only under circumstances in which the GPF 23 is not damaged.

[0114] The number M of stopped cylinders and the number N of combustion cylinders set in the first fuel cut process are not limited to the examples of the above embodiment. Similarly, the number M of stopped cylinders and the number N of combustion cylinders set in the second fuel cut process are not limited to the examples of the above embodiment. The number M of stopped cylinders and the number N of combustion cylinders in each fuel cut process may be set so that the following relationship is established. That is, the relationship that the value of "M / N" in the second fuel cut process is greater than the value of "M / N" in the first fuel cut process may be established. If this relationship is established, for example, the number M of stopped cylinders in the first fuel cut process and the number M of stopped cylinders in the second fuel cut process may not be consecutive. That is, the number M of stopped cylinders in the first fuel cut process may be "1", and the number M of stopped cylinders in the second fuel cut process may be "3". In addition, the sum of "M" and "N" does not have to match the total number of cylinders 11. If the sum of "M" and "N" does not match the total number of cylinders 11, the stopped cylinders and the burning cylinders may change for each combustion cycle, or some combustion cycles may not have any burning cylinders. Even if the number M of stopped cylinders and the number N of burning cylinders are changed from the example of the above embodiment, "M" and "N" may be integers equal to or greater than 1.

[0115] It is not essential to perform the second fuel cut. That is, in the above configuration, the second fuel cut process and the second determination process may be omitted. Then, only the first fuel cut process may be executable as a process for removing PM from the GPF 23. Even in this case, PM can be removed from the GPF 23 by executing the first fuel cut process.

[0116] It is not essential that the air-fuel ratio of the mixture in the combustion cylinder is the air-fuel ratio. For example, the air-fuel ratio of the combustion cylinder may be made richer than the theoretical air-fuel ratio. In this case, the combustion cylinder discharges unburned fuel into the exhaust passage 21. This unburned fuel is burned in the three-way catalyst 22, causing the temperature of the exhaust gas to rise. This exhaust gas reaches the GPF 23, causing the temperature of the GPF 23 to rise. If the temperature of the GPF 23 increases, PM becomes more easily combusted.

[0117] The configuration of the internal combustion engine 10 is not limited to the example of the above embodiment. For example, the number of cylinders may be changed. The internal combustion engine only needs to have a plurality of cylinders, a filter that collects particulate matter in the exhaust gas discharged from the cylinders, and a crankshaft.

[0118] The method of calculating the PM deposition amount Z is not limited to the example of the above embodiment. For example, a differential pressure sensor may be provided to detect the pressure difference between the upstream side and the downstream side of the GPF 23. Then, the PM deposition amount Z may be calculated using the detection value of the differential pressure sensor.

[0119] The method of calculating the temperature TF of the GPF 23 is not limited to the example of the above embodiment. For example, the temperature TF of the GPF 23 may be calculated based on the engine speed NE, the engine load KL, the fuel injection amount, etc. In this case, a map or the like showing the relationship between these parameters and the temperature TF of the GPF 23 may be created in advance. When this modified example is adopted, the first temperature sensor 62 can be omitted.

[0120] The configuration of the automatic transmission 50 is not limited to the example of the above embodiment. The automatic transmission 50 may include an input shaft, an output shaft connected to the drive wheels, and a speed change mechanism that reduces the rotation of the input shaft and transmits it to the output shaft. The speed change mechanism may be capable of switching to a neutral range in which torque is not transmitted from the input shaft to the output shaft.

[0121] The overall configuration of the vehicle 500 is not limited to the example of the above embodiment. For example, the vehicle may be configured as a hybrid vehicle having an internal combustion engine and a motor generator as the drive source of the vehicle. Here, if the number of stopped cylinders in the fuel cut process is increased, the internal combustion engine may not be able to maintain the idle rotation speed. In this case, if the vehicle has a motor generator as a drive source, it is possible to apply the torque of the motor generator to the internal combustion engine to assist the drive of the internal combustion engine.

[0122] The method of determining whether the road is a downhill road is not limited to the example of the above embodiment. For example, an acceleration sensor may be provided in the vehicle 500. Then, the road surface gradient of the road on which the base vehicle 500 is traveling may be calculated based on the detected value of the acceleration sensor. Then, based on the road surface gradient, it may be determined whether the road is a downhill road. [Explanation of symbols]

[0123] 10. Internal combustion engine 11…Cylinder 23…GPF 31…Crankshaft 50…Automatic transmission 52…Input shaft 54…Output shaft 56...Gear shift mechanism 60…Drive wheel 100...Control device 500…Vehicle

Claims

1. An internal combustion engine including a plurality of cylinders, a filter that collects particulate matter in exhaust gas discharged from the cylinders, and a crankshaft; an automatic transmission including an input shaft connected to the crankshaft, an output shaft connected to driving wheels, and a speed change mechanism that reduces the rotation of the input shaft and transmits the reduced rotation to the output shaft, the speed change mechanism being switchable to a neutral range in which no torque is transmitted from the input shaft to the output shaft; This applies to vehicles having a fuel cut process in which a stop pattern in which fuel supply to M consecutive cylinders in the order of the cylinders entering a combustion stroke, where "M" and "N" are integers equal to or greater than 1, is alternately repeated while continuing operation of the internal combustion engine, and a combustion pattern in which fuel supply to N consecutive cylinders in the order of the cylinders entering a combustion stroke, where "M" and "N" are integers equal to or greater than 1; a first estimation process for calculating, as a first temperature, an estimated temperature of the filter when it is assumed that a current amount of the particulate matter accumulated in the filter has been reduced to a predetermined final accumulation amount by executing the fuel cut process; The fuel cut process is executed when a predetermined first start condition is satisfied, The first start condition is: the transmission mechanism is in the neutral range; The vehicle is traveling on a downhill road. the first temperature being equal to or lower than a predetermined set temperature; This includes all of the following: Vehicle control device.

2. When the fuel cut process executed with predetermined values ​​of "M" and "N" is defined as a first fuel cut process, and the fuel cut process executed with predetermined values ​​of "M" and "N" in which the value of "M / N" is larger than that in the first fuel cut process is defined as a second fuel cut process, a second estimation process for calculating, as a second temperature, an estimated temperature of the filter when it is assumed that a current amount of the particulate matter accumulated in the filter has been reduced to the final accumulation amount by executing the second fuel cut process during execution of the first fuel cut process, The second fuel cut process is executed when a predetermined second start condition is satisfied, The second start condition is: the second temperature being equal to or lower than the set temperature; the amount of particulate matter currently deposited on the filter is equal to or less than a predetermined set deposition amount; This includes all of the following: The vehicle control device according to claim 1 .

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