Control method of internal combustion engine and control device of internal combustion engine

Abstract

With respect to the internal combustion engine (1), automatic stop is performed if a prescribed idle stop condition is satisfied, and automatic restart is performed if a prescribed idle stop cancellation condition is satisfied. In the operation of the vehicle, in a case where new gas does not flow into the GPF (18) even if fuel injection is stopped, the internal combustion engine (1) is controlled in such a manner that fuel injection stop is permitted in a state where the temperature of the GPF (18) is high. That is, when the temperature of the GPF (18) is higher than a prescribed temperature T1, the internal combustion engine (1) prohibits fuel injection stop, and in a case where the vehicle is stopped in a state where the temperature of the GPF (18) is higher than the prescribed temperature T1, the internal combustion engine (1) is able to stop fuel injection.

Description

TECHNICAL FIELD

[0001] The present application relates to a control method of an internal combustion engine and a control device of an internal combustion engine. BACKGROUND

[0002] For example, Patent Document 1 discloses a technology in which, in a case where the temperature of a GPF (Gasoline Particulate Filter) provided in an exhaust passage of an internal combustion engine is higher than a prescribed temperature (prohibited temperature) at the time of deceleration operation of a vehicle, fuel cut of the internal combustion engine is prohibited and the amount of oxygen supply to the GPF is limited so that the soot accumulated in the GPF does not burn all at once and heat deterioration of the GPF is prevented.

[0003] However, in Patent Document 1, if the temperature of the GPF is higher than the prescribed temperature (prohibited temperature), fuel cut is always prohibited, and the fuel consumption of the internal combustion engine can deteriorate.

[0004] For example, it can be conceived that, if the state in which the amount of oxygen supply to the GPF is limited, even when fuel cut (stop of fuel injection) of the internal combustion engine is implemented at the time when the temperature of the GPF is higher than the prescribed temperature (prohibited temperature), the soot accumulated in the GPF does not burn all at once.

[0005] That is, with respect to an internal combustion engine having a GPF, there is room for further improvement in prohibiting fuel cut of the internal combustion engine in accordance with the temperature of the GPF.

[0006] Patent Document 1: Japanese Patent Application Publication No. 2020-12404 SUMMARY

[0007] The internal combustion engine of the present application prohibits stop of fuel injection when the temperature of an exhaust particulate filter provided in an exhaust passage of the internal combustion engine is higher than a prescribed temperature, and can stop fuel injection in a case where the vehicle is stopped in a state where the temperature of the exhaust particulate filter is higher than the prescribed temperature.

[0008] According to the present application, in a state where the vehicle is stopped, even when fuel injection is stopped, the exhaust particulate filter does not cause desired performance to be impaired, and improvement in fuel consumption can be achieved by stopping fuel injection. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 is an explanatory diagram schematically showing the system structure of an internal combustion engine to which the present application is applied.

[0010] Figure 2 is an explanatory diagram schematically showing the state of a GPF.

[0011] Figure 3 is a time chart showing one example of the operation at the time when the vehicle is temporarily stopped.

[0012] Figure 4 is a timing chart showing one example of an operation when the vehicle is temporarily stopped.

[0013] Figure 5 is a flowchart showing a control flow of the internal combustion engine according to the present application. DETAILED DESCRIPTION

[0014] Hereinafter, one embodiment of the present application will be described in detail based on the drawings. Figure 1 is an explanatory diagram schematically showing a system structure of the internal combustion engine 1.

[0015] The internal combustion engine 1 is, for example, a spark-ignition type internal combustion engine of in-line 3-cylinder, and is fueled with gasoline, and is mounted as a drive source on a vehicle such as an automobile. That is, the internal combustion engine 1 drives a drive wheel (not shown) of the vehicle on which the internal combustion engine 1 is mounted.

[0016] The internal combustion engine 1 is, for example, a spark-ignition type internal combustion engine of in-line 3-cylinder, and is fueled with gasoline, and is mounted as a drive source on a vehicle such as an automobile. That is, the internal combustion engine 1 drives a drive wheel (not shown) of the vehicle on which the internal combustion engine 1 is mounted.

[0017] A fuel injection valve 5 that injects fuel toward the intake valve 2 is disposed at an intake port 6 of the internal combustion engine 1. In addition, the internal combustion engine 1 can be an in-cylinder direct injection type internal combustion engine that directly injects fuel into the cylinder.

[0018] An intake passage 7 connected to the intake port 6 has an intake manifold 7a. On the upstream side of the intake manifold 7a, an air cleaner 8, an air flow meter 9, and an electronically controlled throttle valve 10 are disposed in this order from the upstream side.

[0019] A catalytic device 15 composed of a three-way catalyst is provided at an exhaust passage 14 of the internal combustion engine 1 connected to an exhaust port 13.

[0020] An air-fuel ratio sensor 16 is disposed on the upstream side of the catalytic device 15. An O2 sensor 17 is disposed on the downstream side of the catalytic device 15. In addition, on the exhaust passage 14, further on the downstream side than the O2 sensor 17, a particulate matter filter (hereinafter, simply referred to as GPF) 18 that traps PM that is particulate matter in exhaust gas is disposed. The GPF 18 is, for example, a structure in which a three-way catalyst is applied to a ceramic monolithic filter of a plugged type. The catalytic device 15 on the upstream side is, for example, located in an engine room of the vehicle. In addition, the GPF 18 is, for example, located under a floor of the vehicle.

[0021] The GPF 18 has an inlet-side temperature sensor 19 at the inlet side thereof and an outlet-side temperature sensor 20 at the outlet side thereof. The inlet-side temperature sensor 19 detects the exhaust gas temperature at the inlet side of the GPF 18. The outlet-side temperature sensor 20 detects the exhaust gas temperature at the outlet side of the GPF 18. In addition, the GPF 18 has a differential pressure sensor 21 that responds to the pressure difference between the inlet side and the outlet side of the GPF 18 in order to detect the pressure loss of the GPF 18 (i.e., the particulate accumulation state).

[0022] The internal combustion engine 1 is capable of implementing exhaust gas recirculation (EGR) in which a portion of the exhaust gas is introduced (recirculated) from the exhaust passage 14 to the intake passage 7 as EGR gas, and has an exhaust gas recirculation passage 23 that branches from the exhaust passage 14 and is connected to the intake passage 7.

[0023] An electrically driven EGR valve 25 that controls the flow rate of the EGR gas in the exhaust gas recirculation passage 23, and an EGR cooler 24 that is capable of cooling the EGR gas, are provided in the exhaust gas recirculation passage 23.

[0024] In addition, the internal combustion engine 1 has various sensors such as a coolant temperature sensor 27 that detects the temperature of the coolant of the internal combustion engine 1, and a crank angle sensor 31 that detects the crank angle of the crankshaft (not shown). The crank angle sensor 31 is capable of detecting the engine speed of the internal combustion engine 1.

[0025] The detection signals of the above-described various sensors are input to an engine controller 35. The engine controller 35 also has input thereto the detection signal of an accelerator opening sensor 36 that detects the amount of depression of an accelerator pedal operated by the driver, the detection signal of an acceleration sensor 37 that is capable of detecting the acceleration of the vehicle, the vehicle speed signal from a vehicle speed sensor 38 that is capable of detecting the vehicle speed of the vehicle, and the like. The acceleration sensor 37 is capable of detecting the acceleration in the front-rear direction of the vehicle.

[0026] The engine controller 35 calculates the requested load (engine load) of the internal combustion engine 1 using the detection signal (detection value) of the accelerator opening sensor 36. In addition, the engine controller 35 is capable of calculating the State Of Charge (SOC) that is the ratio of the charge remaining amount to the charge capacity of the vehicle-mounted battery (not shown).

[0027] The engine controller 35 performs overall control of the internal combustion engine 1 based on the above-described detection signals. For example, the fuel injection amount and injection timing of the fuel injection valve 5 of each cylinder, the ignition timing of the spark plug 4, the opening of the throttle valve 10, the opening of the EGR valve 25, and the like are controlled to be optimal.

[0028] When a particulate accumulation state (so-called clogging state) equal to or greater than a predetermined level is detected in the GPF 18 , the engine controller 35 also performs control (GPF regeneration control) to forcibly regenerate the GPF 18 in consideration of other conditions such as the temperature of the GPF 18 .

[0029] Specifically, the GPF regeneration control increases the opening of the throttle valve 10 to increase the intake air and fuel amounts, and retards the ignition timing to increase the exhaust temperature, thereby burning and removing the accumulated exhaust particulate matter.

[0030] For example, the engine controller 35 calculates the temperature of the GPF 18 using detection signals from the inlet temperature sensor 19 and the outlet temperature sensor 20 . For example, the engine controller 35 calculates the amount of exhaust particulate matter accumulated in the GPF 18 using detection signals from the differential pressure sensor 21 .

[0031] Furthermore, normally, when the temperature of the GPF 18 is high due to high-load operation, etc., the GPF 18 can be naturally regenerated. Therefore, when the temperature of the GPF 18 is low due to continued low-load operation, etc., forced regeneration of the GPF 18 is performed. For example, forced regeneration of the GPF 18 is also performed when the driver releases the accelerator pedal, that is, when the accelerator opening is "0."

[0032] If a predetermined automatic stop condition is met while the vehicle is traveling or stopped, the internal combustion engine 1 automatically stops by stopping the fuel supply. Furthermore, if a predetermined automatic restart condition is met during the automatic stop, the internal combustion engine 1 is restarted. Specifically, the engine controller 35 automatically stops the internal combustion engine 1 if the predetermined automatic stop condition is met, and automatically restarts the internal combustion engine 1 if the predetermined automatic restart condition is met.

[0033] The automatic stop conditions of the internal combustion engine 1 include, for example, a state in which the accelerator pedal is not depressed and a battery SOC of the vehicle-mounted battery is greater than a predetermined battery threshold.

[0034] If all of the above-mentioned automatic stop conditions are met, the internal combustion engine 1 automatically stops. In other words, if all of the above-mentioned automatic stop conditions are met while the internal combustion engine 1 is operating, the engine controller 35 automatically stops the internal combustion engine 1. Specifically, the engine controller 35 acts as a control unit that stops fuel injection and automatically stops the internal combustion engine 1 when the predetermined automatic stop conditions are met.

[0035] The automatic restart conditions of the internal combustion engine 1 include, for example, a state where the accelerator pedal is depressed, a battery SOC of the vehicle-mounted battery being equal to or less than a predetermined battery threshold, and the like.

[0036] If there is a request for restart in the automatic stop, the internal combustion engine 1 is caused to restart. In other words, if any one of the above-described automatic restart conditions is established in the automatic stop of the internal combustion engine 1, the engine controller 35 causes the internal combustion engine 1 to restart. For example, if the battery SOC of the vehicle-mounted battery is less than or equal to a prescribed battery threshold value, the internal combustion engine 1 in the automatic stop is caused to restart.

[0037] That is, the engine controller 35 corresponds to a control section that causes the internal combustion engine 1 to restart from the automatic stop if the prescribed automatic restart condition is established.

[0038] As the automatic stop of the internal combustion engine 1, for example, there are included an idle stop, a coast stop, and a sailing stop.

[0039] The idle stop is implemented at the time of temporary stop of the vehicle, for example, in a case where the above-described automatic stop condition is established. In addition, for example, if any one of the above-described automatic restart conditions is established, the idle stop is released.

[0040] The coast stop is implemented in the running of the vehicle, for example, in a case where the above-described automatic stop condition is established. In addition, if any one of the above-described automatic restart conditions is established, for example, the coast stop is released. Further, the coast stop refers to, for example, the automatic stop of the internal combustion engine 1 in deceleration in a state where the brake pedal is depressed at a low vehicle speed.

[0041] The sailing stop is implemented in the running of the vehicle, for example, in a case where the above-described automatic stop condition is established. In addition, the sailing stop is released in a case where any one of the above-described automatic restart conditions is established, for example. Further, the sailing stop refers to, for example, the automatic stop of the internal combustion engine 1 in inertial running in which the brake pedal is not depressed at a medium-high vehicle speed.

[0042] That is, the above-described automatic stop condition is a superordinate concept that includes an idle stop condition for performing the idle stop, a coast stop condition for performing the coast stop, and a sailing stop condition for performing the sailing stop.

[0043] In addition, the above-described automatic restart condition is a superordinate concept that includes an idle stop release condition for performing the release of the idle stop, a coast stop release condition for performing the release of the coast stop, and a sailing stop release condition for performing the release of the sailing stop.

[0044] Here, in the case where the fuel injection of the internal combustion engine 1 is stopped (fuel cut) in a state where the temperature of the GPF 18 is high due to the middle of the regeneration of the GPF 18 in the operation of the vehicle, the temperature of the GPF 18 excessively increases due to the inflow of the new gas, and it is likely that the exhaust performance of the GPF 18 and the like are adversely affected.

[0045] In the case where the stop of the fuel injection of the internal combustion engine 1 is prohibited in a state where the temperature of the GPF 18 is high, the excessive increase in the temperature of the GPF 18 due to the inflow of the new gas is prevented, but the stop of the fuel injection of the internal combustion engine 1 is always prohibited in a state where the temperature of the GPF 18 is high, and it is likely that the fuel consumption deteriorates.

[0046] In addition, with regard to the idling stop performed in a state where the vehicle is stopped, if the fuel injection of the internal combustion engine 1 is stopped (fuel cut), the rotation of the crankshaft is stopped, and the new gas does not flow into the GPF 18.

[0047] Therefore, the engine controller 35 controls the internal combustion engine 1 in such a manner that, in the operation of the vehicle, in the case where the new gas does not flow into the GPF 18 even if the fuel injection is stopped (fuel cut), the stop of the fuel injection (fuel cut) is permitted in a state where the temperature of the GPF 18 is high.

[0048] That is, the engine controller 35 basically prohibits the stop of the fuel injection when the temperature of the GPF 18 is higher than the prescribed temperature, and the fuel injection can be stopped in the case where the vehicle is stopped in a state where the temperature of the GPF 18 is higher than the prescribed temperature.

[0049] In detail, the engine controller 35 corresponds to a control portion that prohibits the stop of the fuel injection when the temperature in the regeneration of the GPF 18 is higher than the prescribed temperature T1 and the accumulation amount of the exhaust particulates accumulated in the GPF 18 is greater than or equal to the prescribed second accumulation amount V2 (first accumulation amount) in the operation of the vehicle, and the fuel injection can be stopped in the case where the vehicle is stopped even in the regeneration of the GPF 18 in a state where the temperature of the GPF 18 is higher than the prescribed temperature T1 and the accumulation amount of the exhaust particulates accumulated in the GPF 18 is greater than or equal to the prescribed second accumulation amount V2.

[0050] In a state where the vehicle is stopped, the rotation of the crankshaft of the internal combustion engine 1 is stopped, and the new gas does not flow into the GPF 18, and it is possible to avoid the GPF 18 from becoming an excessively high temperature even if the fuel injection is stopped (fuel cut). That is, in a state where the vehicle is stopped, even if the fuel injection is stopped (fuel cut), the GPF 18 does not become a state where the desired performance is impaired, and it is possible to achieve the improvement in the fuel consumption by stopping the fuel injection (fuel cut).

[0051] Further, in a case where the temperature of the GPF 18 is less than or equal to a predetermined temperature and the accumulation amount of the exhaust particulates accumulated in the GPF 18 is greater than or equal to a predetermined amount when the vehicle is stopped, the engine controller 35 prohibits the stop of fuel injection.

[0052] Specifically, in a case where the temperature of the GPF 18 is less than or equal to a predetermined temperature T1 and the accumulation amount of the exhaust particulates accumulated in the GPF 18 is greater than or equal to a predetermined first accumulation amount V1 (second accumulation amount) when the vehicle is stopped, the engine controller 35 prohibits the stop of fuel injection. The first accumulation amount V1 is a value smaller than the above-described second accumulation amount V2.

[0053] In a case where the temperature of the GPF 18 is low (less than or equal to a predetermined temperature T1) and the accumulation amount of the exhaust particulates of the GPF 18 is greater than or equal to a predetermined amount (first accumulation amount V1), the stop of fuel injection (fuel cut) is prohibited to promote the temperature increase of the GPF 18, and thus appropriate purification effect of the GPF 18 can be obtained at all times.

[0054] Further, in a case where the temperature of the GPF 18 is higher than a predetermined temperature and the accumulation amount of the exhaust particulates accumulated in the GPF 18 is less than a predetermined amount, the engine controller 35 can stop fuel injection.

[0055] Specifically, in a case where the temperature of the GPF 18 is higher than a predetermined temperature T1 and the accumulation amount of the exhaust particulates accumulated in the GPF 18 is less than a first accumulation amount V1, the engine controller 35 can stop fuel injection (fuel cut).

[0056] In a case where the purification effect of the GPF 18 is appropriately obtained without affecting the exhaust performance, the stop of fuel injection (fuel cut) can be permitted, and thus improvement of fuel consumption can be achieved.

[0057] The engine controller 35 determines the stop of the vehicle using a detection signal of the acceleration sensor 37 and a detection signal of the vehicle speed sensor 38.

[0058] Thus, by determining the stop of the vehicle using different two (two kinds) of sensors, even in a case where one sensor malfunctions, it is possible to prevent a case where the vehicle is erroneously determined to be stopped, the GPF 18 becomes an excessively high temperature, and the desired performance is impaired.

[0059] Figure 2 is a diagram schematically showing the state of the GPF 18 with the temperature of the GPF 18 as a vertical axis and the accumulation amount of the exhaust particulates of the GPF 18 (PM accumulation amount) as a horizontal axis.

[0060] Region 1 is a region including a region in which the temperature of the GPF 18 is higher than the prescribed temperature T1 and the PM accumulation amount of the GPF 18 is smaller than the above-described first accumulation amount V1.

[0061] Specifically, region 1 is a region in which the temperature of the GPF 18 is higher than the prescribed temperature T1 and smaller than or equal to a prescribed high-temperature threshold T2 and the PM accumulation amount of the GPF 18 is smaller than the first accumulation amount V1, the temperature of the GPF 18 is higher than the prescribed temperature T1 and smaller than or equal to the prescribed high-temperature threshold T2 and the PM accumulation amount of the GPF 18 is larger than or equal to the first accumulation amount V1 and smaller than a second accumulation amount V2, and the temperature of the GPF 18 is smaller than or equal to the prescribed temperature T1 and the PM accumulation amount of the GPF 18 is smaller than the first accumulation amount V1, taken together.

[0062] Region 1 is a normal region in which the exhaust gas purification effect achieved by the GPF 18 can be obtained. In a case where the state of the GPF 18 is within region 1, fuel cut based on automatic stop of the internal combustion engine 1 is permitted.

[0063] Region 2 is a region including a region in which the temperature of the GPF 18 is smaller than or equal to the prescribed temperature T1 and the PM accumulation amount of the GPF 18 is larger than or equal to the prescribed first accumulation amount.

[0064] Specifically, region 2 is a region in which the temperature of the GPF 18 is smaller than the prescribed temperature T1 and the PM accumulation amount of the GPF 18 is larger than or equal to the first accumulation amount V1 and smaller than a prescribed third accumulation amount V3. The third accumulation amount V3 is a value larger than the second accumulation amount V2.

[0065] Region 2 is a heating region in which the temperature of the GPF 18 is increased. In region 2, the internal combustion engine 1 is controlled, for example, in such a manner that the flowability of the combustion chamber is increased so that the residual gas ratio of the internal combustion engine 1 is decreased. Also, in region 2, the internal combustion engine 1 is controlled, for example, in such a manner that the internal combustion engine 1 is operated at an operating point on the high-load side as compared with region 1. Also, in region 2, the internal combustion engine 1 is controlled, for example, in such a manner that the air-fuel ratio is set to the stoichiometric air-fuel ratio so that the ignition timing is retarded as compared with the normal ignition timing. In a case where the state of the GPF 18 is within region 2, fuel cut based on automatic stop of the internal combustion engine 1 is prohibited. In a case where the state of the GPF 18 is within region 2, the internal combustion engine 1 is controlled overall in such a manner that the temperature and the PM accumulation amount of the GPF 18 are within region 1 or region 3.

[0066] Region 3 is a region including a region in which the temperature of the GPF 18 is higher than the prescribed temperature T1 and the PM accumulation amount of the GPF 18 is larger than or equal to the prescribed second accumulation amount V2.

[0067] Specifically, region 3 is a region in which the temperature of the GPF 18 is higher than the prescribed temperature T1 and lower than a prescribed high-temperature threshold T2, and the PM accumulation amount of the GPF 18 is greater than or equal to the 2nd accumulation amount V2 and lower than the 3rd accumulation amount V3.

[0068] Region 3 is a regeneration region in which the GPF 18 is regenerated. In addition, region 3 is a region in which the temperature of the GPF 18 is relatively high and the PM accumulation amount is relatively large, and is a region in which the exhaust temperature is desired to be reduced as compared with region 2.

[0069] In region 3, for example, in order to reduce the exhaust temperature, the air-fuel ratio is made rich as compared with region 2, and the internal combustion engine 1 is controlled in such a manner that the ignition timing is not retarded with respect to the normal ignition timing. In a case where the state of the GPF 18 is within region 3, if the vehicle is in a stop, fuel cut based on automatic stop of the internal combustion engine 1 is permitted. In a case where the state of the GPF 18 is within region 3, if the vehicle is not in a stop, fuel cut based on automatic stop of the internal combustion engine 1 is prohibited. In a case where the state of the GPF 18 is within region 3, the temperature and the PM accumulation amount of the GPF 18 are controlled to be within region 1 or region 2 in general.

[0070] Region 4 is a region in which the temperature of the GPF 18 is higher than the high-temperature threshold T2 and the PM accumulation amount of the GPF 18 is lower than the prescribed 3rd accumulation amount V3. Region 4 is an overheating region in which the temperature of the GPF 18 is relatively high. The engine controller 35 controls the internal combustion engine 1 so that the state of the GPF 18 does not fall within region 4.

[0071] Region 5 is a region in which the PM accumulation amount of the GPF 18 is greater than or equal to the prescribed 3rd accumulation amount V. Region 5 is a use prohibition region. The engine controller 35 controls the internal combustion engine 1 so that the state of the GPF 18 does not fall within region 4. In a case where the state of the GPF 18 falls within region 5, for example, it is necessary to notify the driver by causing a warning light to be displayed or the like, and maintenance of the GPF 18 is performed at a repair factory or the like.

[0072] Figure 3 is a timing chart indicating one example of the operation when the state of the GPF 18 is within region 3 and the vehicle is temporarily stopped.

[0073] Figure 3 The time t1 of is a timing at which the vehicle speed detected by the vehicle speed sensor 38 becomes "0". Figure 3 The time t2 of is a timing at which the actual vehicle speed of the vehicle becomes "0". Figure 3 The time t3 of is a timing at which the deceleration of the vehicle detected by the acceleration sensor 37 becomes "0". Figure 3 The time t4 of is a timing at which movement from a state in which the vehicle is stopped is started.

[0074] In Figure 3 In the example shown, the vehicle stops on a flat ground, so the deceleration is "0" between time t3 and time t4. Figure 3 In the example shown, at time t3, the timed idle stop condition (automatic stop condition) is met, and the flag indicating the idle stop request switches from "0" to "1." When the idle stop request flag is "0," idle stop is not requested, and when the flag is "1," idle stop is requested.

[0075] like Figure 3 As shown, the accuracy of the detection value of the vehicle speed sensor 38 may decrease immediately before the vehicle stops. Consequently, there may be a discrepancy between the timing at which the vehicle stops, as detected by the detection signal of the acceleration sensor 37, and the timing at which the vehicle stops, as detected by the vehicle speed sensor 38. In the above embodiment, the vehicle is determined to have stopped when a predetermined time has elapsed from the timing at which the vehicle stops, as detected by the speed sensor 38 (time t3 when the vehicle stops, as detected by the detection signal of the acceleration sensor 37).

[0076] exist Figure 3 In the example shown, at time t3, the state of the GPF 18 is within the aforementioned zone 3. Therefore, at time t3 when the vehicle is determined to be stopped, the flag indicating the fuel cut request from the GPF 18 is switched from "1" to "0." The fuel cut request from the GPF 18 permits fuel cut when the flag is "0" and prohibits fuel cut when the flag is "1."

[0077] The flag indicating a fuel cut request from the GPF 18 is set to "0" to allow fuel cut when the state of the GPF 18 is in zone 1. The flag indicating a fuel cut request from the GPF 18 is set to "1" to prohibit fuel cut when the state of the GPF 18 is in zone 2. The flag indicating a fuel cut request from the GPF 18 is set to "0" to allow fuel cut if the vehicle is stopped when the state of the GPF 18 is in zone 3. The flag indicating a fuel cut request from the GPF 18 is set to "1" to prohibit fuel cut if the vehicle is not stopped when the state of the GPF 18 is in zone 3.

[0078] Therefore, in Figure 3 In the example shown, at time t3 , the flag indicating the idle stop request becomes “1”, the flag indicating the fuel cut request from the GPF 18 becomes “0”, and fuel injection into the internal combustion engine 1 is stopped, thereby stopping the internal combustion engine 1 .

[0079] exist Figure 3 In the example shown, the idling stop cancellation condition (automatic restart condition) is satisfied at time t4, and the flag indicating the idling stop request is switched from "1" to "0". Figure 3 In the example shown, the flag indicating the fuel cut request from the GPF 18 is accepted, the vehicle starts moving, and the timing at time t4 switches from "0" to "1".

[0080] Therefore, in Figure 3 In the example shown, at the timing of time t4, the flag indicating the idle stop request becomes "0", the flag indicating the fuel cut request from the GPF 18 becomes "1", fuel injection of the internal combustion engine 1 is restarted, and the internal combustion engine 1 is started.

[0081] In the case where the temperature of the GPF 18 is high, in the case where the stop (fuel cut) of the fuel injection of the internal combustion engine 1 is prohibited in all, as Figure 3 indicated by the broken line in FIG. 10, the fuel cut request from the GPF 18 does not switch to "0" at time t3, and the fuel consumption deteriorates in correspondence with the operation of the internal combustion engine 1 during the period from time t3 to time t4.

[0082] That is, in the case where the state of the GPF 18 is within the region 3, if the fuel cut of the internal combustion engine 1 is prohibited even if the idle stop condition is satisfied although the temperature is high, as Figure 3 indicated by the broken line in FIG. 10, the fuel consumption deteriorates in correspondence with the operation of the internal combustion engine 1 during the period from time t3 to time t4.

[0083] Figure 4 is a timing chart indicating one example of the operation when the vehicle temporarily stops while the state of the GPF 18 is within the region 2.

[0084] Figure 4 Time t1 of FIG. 9 is a timing at which the vehicle speed detected by the vehicle speed sensor 38 becomes "0". Figure 4 Time t2 of FIG. 9 is a timing at which the actual vehicle speed of the vehicle becomes "0". Figure 4 Time t3 of FIG. 9 is a timing at which the deceleration of the vehicle detected by the acceleration sensor 37 becomes "0". Figure 4 Time t4 of FIG. 9 is a timing at which the vehicle starts moving from the stopped state.

[0085] In Figure 4 In the example shown, the temperature of the GPF 18 is low, and therefore the idle stop condition (automatic stop condition) does not hold at the timing of time t3, and the flag indicating the idle stop request is maintained at "0". In Figure 4 In the example shown, the state of the GPF 18 is within the region 2 at time t3, and therefore at the timing of time t3 at which it is determined that the vehicle is stopped, the flag indicating the fuel cut request from the GPF 18 does not switch from "1" to "0".

[0086] Therefore, in Figure 4In the example shown, after the timing of time t3, fuel injection of the internal combustion engine 1 is not stopped, and the internal combustion engine 1 continues idling operation.

[0087] In the case where fuel injection of the internal combustion engine 1 is stopped (fuel cut) in a case where the temperature of the GPF 18 is low, as shown by a dashed line in FIG. 10, the fuel cut request from the GPF 18 is switched to "0" at time t3, and the idle stop request is switched to "1", so that the temperature of the GPF 18 decreases and the exhaust performance deteriorates during a period from time t3 to time t4 in correspondence with the stop of the internal combustion engine 1. Figure 4

[0088] Figure 5 is a flowchart showing a control procedure of the above-described internal combustion engine 1.

[0089] In step S1, it is determined whether the vehicle is parked (stopped). In the case where the vehicle is parked, the procedure proceeds to step S2. In the case where the vehicle is not parked, the procedure for this time is ended.

[0090] In step S2, it is determined whether the GPF 18 is in regeneration. In the case where the GPF 18 is in regeneration, the procedure proceeds to step S3. In the case where the GPF 18 is not in regeneration, the procedure proceeds to step S5.

[0091] In step S3, it is determined whether idle stop is permitted. That is, in step S3, in the case where an idle stop condition is satisfied and fuel cut is permitted in accordance with a fuel cut request from the GPF 18, it is determined that idle stop is permitted. In the case where it is determined that idle stop is permitted, the procedure proceeds to step S4, and fuel cut is implemented.

[0092] In step S5, it is determined whether the GPF 18 is in a heating mode. That is, in step S5, it is determined whether the state of the GPF 18 is within the region 2. In the case where it is determined that the state of the GPF 18 is within the region 2, the procedure proceeds to step S6, and implementation of fuel cut is prohibited. In the case where it is not determined that the state of the GPF 18 is within the region 2, the procedure proceeds to step S3.

[0093] The above describes a specific embodiment of the present application, but the present application is not limited to the above-described embodiment, and various modifications can be made within the scope of the gist thereof.

[0094] The high temperature threshold T2 may, for example, be set to vary in accordance with the PM accumulation amount of the GPF 18. In detail, for the high temperature threshold T2, for example, it can be set to be lower the more the PM accumulation amount of the GPF 18.

[0095] In the case where the stop of the vehicle is determined using the detection signal of the acceleration sensor 37, not only the deceleration of the vehicle but also the amount of change in the deceleration of the vehicle can be used to determine the stop of the vehicle.​

[0096] The above-described embodiments relate to a control method of an internal combustion engine and a control device of an internal combustion engine.

Claims

1. A method for controlling an internal combustion engine, the method being a method for controlling an internal combustion engine mounted on a vehicle capable of automatically stopping the internal combustion engine by stopping fuel injection, wherein: When the temperature of an exhaust particulate filter provided in an exhaust passage of the internal combustion engine is higher than a predetermined temperature and the amount of exhaust particulates accumulated on the exhaust particulate filter is greater than or equal to a predetermined amount, stopping of fuel injection is prohibited. When the temperature of the exhaust particulate filter is higher than the predetermined temperature and the amount of exhaust particulates accumulated on the exhaust particulate filter is less than the predetermined amount, fuel injection can be stopped. When the vehicle stops with the temperature of the exhaust particulate filter higher than the predetermined temperature, fuel injection can be stopped to automatically stop the internal combustion engine.

2. The internal combustion engine control method according to claim 1, wherein: When the vehicle is stopped, if the temperature of the exhaust particulate filter is lower than or equal to the predetermined temperature and the amount of exhaust particulates accumulated on the exhaust particulate filter is greater than or equal to the predetermined amount, stopping of fuel injection is prohibited.

3. The internal combustion engine control method according to claim 1 or 2, wherein: Whether the vehicle has stopped is determined based on a detection signal from a vehicle speed sensor that detects the speed of the vehicle and a detection signal from an acceleration sensor that detects acceleration in a front-rear direction of the vehicle.

4. The internal combustion engine control method according to any one of claims 1 to 3, wherein: When a predetermined time has elapsed since the vehicle stopped, fuel injection is stopped.

5. A control device for an internal combustion engine, wherein: The control device of the internal combustion engine comprises: An internal combustion engine mounted on a vehicle capable of automatically stopping the internal combustion engine by stopping fuel injection; an exhaust particulate filter provided in an exhaust passage of the internal combustion engine; and A control unit that prohibits stopping fuel injection when the temperature of the exhaust particulate filter is higher than a predetermined temperature and the amount of exhaust particulates accumulated on the exhaust particulate filter is greater than or equal to a predetermined amount, and that stops fuel injection when the temperature of the exhaust particulate filter is higher than the predetermined temperature and the amount of exhaust particulates accumulated on the exhaust particulate filter is less than the predetermined amount. When the vehicle stops with the temperature of the exhaust particulate filter higher than the predetermined temperature, fuel injection is stopped to automatically stop the internal combustion engine.

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