vehicle

Abstract

To provide a vehicle in which shock at the time of recover from fuel cut is suppressed while improving regeneration efficiency of a filter.SOLUTION: A vehicle comprises an engine having a throttle valve, a filter that collects exhaust particulates from the engine, and a control device. The control device includes an acquisition unit that acquires a temperature of the engine; a regeneration control unit that increases an opening of the throttle valve as the temperature increases, thereby executing regeneration control of the filter by fuel cut; and a retard control unit that increases a retard amount of ignition timing when returning from the fuel cut as the temperature increases.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] In order to improve the efficiency of filter regeneration by fuel cut, it is known to increase the throttle opening to increase the amount of air supplied to the filter (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-099049 Summary of the Invention [Problem to be solved by the invention]

[0004] However, if the amount of air is increased, the engine output torque will become too large when the fuel supply is restored, which may cause a shock to the vehicle.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a vehicle that improves the efficiency of filter regeneration while suppressing shocks when resuming operation after a fuel cut. [Means for solving the problem]

[0006] The object is to provide a vehicle engine having an engine with a throttle valve, a filter for collecting exhaust particulates from the engine, and a control device, the control device including: an acquisition unit for acquiring a temperature of the engine; Acquired when there is a regeneration request for the filter The higher the temperature, 、 a regeneration control unit that increases the opening of the throttle valve to perform regeneration control of the filter by cutting fuel; The signal obtained when there is a request to return from the fuel cut during the execution of the regeneration control This can be achieved by a vehicle including a retard control unit that increases the amount of retard of the ignition timing when returning from the fuel cut as the temperature increases.

[0007] The engine may include a motor provided on a power transmission path between the engine and drive wheels, and a torque converter having a lock-up clutch provided on the power transmission path between the motor and the drive wheels, wherein the regeneration control includes normal regeneration control that engages the lock-up clutch to perform the fuel cut, and auxiliary regeneration control that releases the lock-up clutch to perform the fuel cut while assisting the rotation of the engine with the motor, and the regeneration control unit may increase the opening of the throttle valve in the auxiliary regeneration control more than the opening of the throttle valve in the normal regeneration control.

[0008] The regeneration control section may control the rate of increase of the throttle valve opening relative to the temperature so that the rate of increase is greater in the normal regeneration control than in the auxiliary regeneration control. [Effects of the Invention]

[0009] According to the present invention, a vehicle can be provided in which the filter regeneration efficiency is improved while suppressing shock when resuming operation after a fuel cut. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of a hybrid vehicle. [Figure 2] FIG. 1 is a schematic diagram of an engine. [Figure 3] 10 is a flowchart illustrating a GPF regeneration control. [Figure 4] 10A and 10B are maps illustrating an example of the throttle opening degree during execution of regeneration control due to fuel cut, and a map illustrating an example of the retard amount of ignition timing when returning from fuel cut. DETAILED DESCRIPTION OF THE INVENTION

[0011] [Hybrid vehicle configuration] FIG. 1 is a schematic diagram of a hybrid vehicle 1. The hybrid vehicle 1 is equipped with an engine 10 and a motor 15 as a power source for traveling. The engine 10 is a gasoline engine having multiple cylinders, but may also be a diesel engine. A transmission unit 11 is provided on a power transmission path from the engine 10 to drive wheels 13. The transmission unit 11 and the left and right drive wheels 13 are drivingly connected via a differential 12.

[0012] The transmission unit 11 is provided with a K0 clutch 14 and a motor 15. The motor 15 is provided on a power transmission path from the engine 10 to the drive wheels 13.

[0013] The K0 clutch 14 is provided between the engine 10 and the motor 15 in the power transmission path. The K0 clutch 14 is engaged when supplied with hydraulic pressure, connecting the power transmission between the engine 10 and the motor 15. The K0 clutch 14 is released when the hydraulic pressure supply is stopped, cutting off the power transmission between the engine 10 and the motor 15. The K0 clutch 14 is in a slip state from when torque transmission begins until it is fully engaged.

[0014] The motor 15 is connected to the battery 16 via an inverter 17. The battery 16 is a rechargeable secondary battery such as a nickel-metal hydride battery or a lithium-ion battery. The motor 15 functions as a motor that generates driving force for the vehicle in response to power supplied from the battery 16. The motor 15 also functions as a generator that generates electric power to charge the battery 16 in response to power transmitted from the engine 10 and the drive wheels 13. The electric power exchanged between the motor 15 and the battery 16 is adjusted by the inverter 17.

[0015] The transmission unit 11 is provided with a torque converter 18 and an automatic transmission 19. The torque converter 18 is a fluid coupling with a torque amplification function. The automatic transmission 19 is a stepped transmission that switches the gear ratio in multiple stages. The torque converter 18 is provided on the power transmission path between the motor 15 and the drive wheels 13. The automatic transmission 19 is provided on the power transmission path between the torque converter 18 and the drive wheels 13. The torque converter 18 is provided with a lock-up clutch (hereinafter referred to as an LU clutch) 20 that receives a supply of hydraulic pressure and engages to directly connect the motor 15 and the automatic transmission 19.

[0016] The LU clutch 20 is engaged when hydraulic pressure is supplied, connecting the power transmission between the motor 15 and the drive wheels 13. The LU clutch 20 is released when the hydraulic pressure supply is stopped. The LU clutch 20 is in a slip state from the released state to the engaged state.

[0017] The transmission unit 11 is further provided with an oil pump 21 and a hydraulic control mechanism 22. The hydraulic pressure generated by the oil pump 21 is supplied to the K0 clutch 14, the torque converter 18, the automatic transmission 19, and the LU clutch 20 via the hydraulic control mechanism 22. The hydraulic control mechanism 22 is provided with hydraulic circuits for each of the K0 clutch 14, the torque converter 18, the automatic transmission 19, and the LU clutch 20, and various hydraulic control valves for controlling the operating hydraulic pressures thereof.

[0018] The hybrid vehicle 1 is provided with an ECU (Electronic Control Unit) 50 as a control device for the hybrid vehicle. The ECU 50 is an electronic control unit that includes a processing circuit that performs various types of calculations related to vehicle driving control, and a memory that stores control programs and data. The ECU 50 is an example of a control device, and functionally realizes an acquisition unit, a regeneration control unit, and a retard control unit, which will be described in detail later.

[0019] The ECU 50 is connected to an ignition switch 61, a crank angle sensor 62, an air flow meter 63, air-fuel ratio sensors 64 and 65, and a water temperature sensor 66. The ignition switch 61 detects whether the ignition is on or off. The crank angle sensor 62 detects the rotation speed of the crankshaft of the engine 10. The air flow meter 63 detects the amount of intake air introduced into the engine 10. The air-fuel ratio sensors 64 and 65 detect the air-fuel ratio of the exhaust gas from the engine 10. The water temperature sensor 66 detects the temperature of the coolant that cools the engine 10.

[0020] The ECU 50 controls the operation of the engine 10 and the motor 15. Specifically, the ECU 50 controls the inverter 17 to adjust the amount of electric power exchanged between the motor 15 and the battery 16, thereby controlling the torque of the motor 15. The ECU 50 controls the operation of the K0 clutch 14, the LU clutch 20, and the automatic transmission 19 through the control of the hydraulic control mechanism 22.

[0021] The ECU 50 drives the hybrid vehicle 1 in either a motor driving mode or a hybrid driving mode. In the motor driving mode, the ECU 50 disengages the K0 clutch 14 to rotate the drive wheels 13 using the power of the motor 15. In the hybrid driving mode, the ECU 50 engages the K0 clutch 14 to rotate the drive wheels 13 using the power of at least one of the engine 10 and the motor 15. For example, when the required driving force for the hybrid vehicle 1 exceeds a driving force threshold, the mode is switched from the motor driving mode to the hybrid driving mode. Furthermore, when the charge amount of the battery 16 falls below a power threshold, the mode is switched from the motor driving mode to the hybrid driving mode.

[0022] [Engine outline] 2 is a schematic diagram of the engine 10. The engine 10 includes a cylinder block 30, a cylinder head 32, a piston 33, a connecting rod 34, a crankshaft 35, an intake passage 36, an intake valve 36v, an exhaust passage 37, and an exhaust valve 37v.

[0023] A cylindrical bore 31 is provided in the cylinder block 30. A piston 33 is housed in the bore 31 so as to be able to reciprocate. A combustion chamber C is defined by the wall surface of the bore 31, the lower surface of the cylinder head 32, and the top surface of the piston 33. The volume of the combustion chamber C increases and decreases as the piston 33 reciprocates.

[0024] The engine 10 is connected to a crankshaft 35, which is the output shaft of the engine 10, via a connecting rod 34. The connecting rod 34 and the crankshaft 35 convert the reciprocating motion of the piston 33 into the rotational motion of the crankshaft 35. The engine 10 is provided with the crank angle sensor 62 described above.

[0025] The intake passage 36 is connected to the combustion chamber C via an intake valve 36v. The exhaust passage 37 is connected to the combustion chamber C via an exhaust valve 37v. The intake passage 36 is provided with the air flow meter 63 described above.

[0026] The cylinder block 30 is provided with an in-cylinder injection valve 41D that injects fuel directly into the combustion chamber C. The intake passage 36 is provided with a port injection valve 41P that injects fuel toward the intake port. The cylinder head 32 is provided with an ignition plug 42 that ignites the mixture of intake air and fuel introduced into the combustion chamber C. Note that only one of the in-cylinder injection valve 41D and the port injection valve 41P may be provided.

[0027] The exhaust passage 37 is provided with a three-way catalyst 43 and a GPF (Gasoline Particulate Filter) 44. The three-way catalyst 43 contains catalytic metal, has oxygen storage capacity, and purifies NOx, HC, and CO. The GPF 44 is a porous ceramic structure that captures exhaust fine particles (hereinafter referred to as PM (Particulate Matter)) in the exhaust gas. The GPF 44 is an example of a filter. Note that, for example, if the engine 10 is a diesel engine, a DPF (Diesel Particulate Filter) is provided instead of the GPF 44.

[0028] An air-fuel ratio sensor 64 is provided between the three-way catalyst 43 and the GPF 44. The air-fuel ratio sensor 64 detects the air-fuel ratio of the exhaust gas discharged from the three-way catalyst 43. An air-fuel ratio sensor 65 is provided downstream of the GPF 44. The air-fuel ratio sensor 65 detects the air-fuel ratio of the exhaust gas discharged from the GPF 44.

[0029] The ECU 50 controls the operation of the engine 10 by controlling the opening of the throttle valve 40, the fuel injection amount of the in-cylinder injection valve 41D and the port injection valve 41P, the ignition timing of the spark plug 42, etc. based on the detection signals of the above-mentioned sensors.

[0030] [Playback Control] The ECU 50 estimates the amount of PM accumulated in the GPF 44, and when the amount of PM accumulated exceeds a predetermined value, requests regeneration control of the GPF 44. The method for estimating the amount of PM accumulated may be, for example, based on the driving history of the engine 10 since the completion of the previous regeneration control, the pressure difference across the GPF 44, or other known methods. In regeneration control, oxygen is supplied to the GPF 44 by cutting fuel to burn the accumulated PM.

[0031] The ECU 50 executes either normal regeneration control or auxiliary regeneration control as regeneration control. Normal regeneration control is regeneration control in which fuel cut is performed while the LU clutch 20 is engaged. When the LU clutch 20 is engaged, power is transmitted from the drive wheels 13 to the engine 10 even during fuel cut, suppressing a decrease in engine 10 rotation. This makes it possible to regenerate the GPF 44 while preventing the engine 10 from stalling. Auxiliary regeneration control is regeneration control in which fuel cut is performed while the LU clutch 20 is disengaged and the motor 15 assists the rotation of the engine 10. Because the motor 15 assists the rotation of the engine 10 even when the LU clutch 20 is disengaged, it is possible to ensure time for fuel cut while preventing the engine 10 from stalling.

[0032] Whether normal regeneration control or auxiliary regeneration control is performed is determined based on, for example, the temperature of the hydraulic oil. If the hydraulic oil is at a low temperature below a predetermined temperature, the LU clutch 20 may not be able to engage, and in such cases auxiliary regeneration control is required. If the hydraulic oil temperature is higher than the predetermined temperature, normal regeneration control is required.

[0033] 3 is a flowchart illustrating the GPF regeneration control. This control is repeatedly executed while the ignition is on. The ECU 50 determines whether or not a regeneration request is made (step S1). If the result in step S1 is No, this control ends.

[0034] If the answer is Yes in step S1, the ECU 50 acquires the water temperature (step S2). Next, the ECU 50 determines whether or not a normal regeneration request is made (step S3). If the answer is Yes in step S3, the ECU 50 executes normal regeneration control (step S4). If the answer is No in step S3, the ECU 50 executes supplemental regeneration control (step S5).

[0035] FIG. 4A is a map showing an example of the throttle opening while regeneration control is being executed due to fuel cut. The horizontal axis represents water temperature, and the vertical axis represents throttle opening. The ECU 50 references the map in FIG. 4A and sets the throttle opening while regeneration control is being executed based on the water temperature acquired in step S2. FIG. 4A specifies the throttle opening for both normal regeneration control and supplemental regeneration control. As shown in FIG. 4A, the throttle opening in either case is specified to increase as the water temperature increases. As will be described in more detail later, this is because the higher the water temperature, the greater the amount of retardation of the ignition timing when resuming operation after fuel cut, thereby suppressing the occurrence of shock when resuming operation after fuel cut.

[0036] Furthermore, when the water temperature is the same, the throttle opening is set to a larger value in auxiliary regeneration control than in normal regeneration control. In auxiliary regeneration control, the LU clutch 20 is in a released state, so the output torque of the engine 10 is not easily transmitted to the drive wheels 13 when the engine resumes from fuel cut. This is because shock is less likely to occur when the engine resumes from fuel cut. Therefore, in auxiliary regeneration control, the throttle opening is increased more than in normal regeneration control, allowing more oxygen to be supplied to the GPF 44, improving regeneration efficiency.

[0037] Furthermore, the rate of increase in throttle opening relative to water temperature is greater in normal regeneration control than in auxiliary regeneration control. That is, normal regeneration control has a greater effect on throttle opening relative to water temperature than auxiliary regeneration control. The higher the water temperature, the greater the amount of retardation of ignition timing when returning from fuel cut, making it possible to suppress the output torque of the engine 10. In auxiliary regeneration control, the LU clutch 20 is in a released state, so shock is less likely to occur when returning from fuel cut. In contrast, in normal regeneration control, the LU clutch 20 is in an engaged state, so the amount of retardation has a greater effect on suppressing shock, and the throttle opening can be increased accordingly.

[0038] Next, the ECU 50 determines whether or not there is a request to resume from fuel cut (step S6). If the answer is No in step S6, this control ends. If the answer is Yes in step S6, the ECU 50 acquires the water temperature (step S7).

[0039] Next, the ECU 50 calculates the amount of ignition timing retardation when the engine resumes from the fuel cut based on the water temperature (step S8). FIG. 4B is a map illustrating an example of the amount of ignition timing retardation when the engine resumes from the fuel cut. The horizontal axis represents the water temperature, and the vertical axis represents the amount of ignition timing retardation. The ECU 50 references the map in FIG. 4B and sets the amount of ignition timing retardation when the engine resumes from the fuel cut based on the water temperature acquired in step S7. The larger the amount of retardation, the more the output torque of the engine 10 can be reduced, so increasing the amount of retardation when the engine resumes from the fuel cut can suppress the occurrence of shock. However, when the water temperature is low, the combustion speed is slow, so if the amount of retardation is too large, there is a risk of misfire. For this reason, the map in FIG. 4B specifies that the amount of ignition timing retardation decreases as the water temperature decreases. Furthermore, when the water temperature drops below a predetermined temperature, the amount of retardation is set to zero.

[0040] Next, the ECU 50 executes control to return from the fuel cut (step S9). In the return control, the ignition timing is retarded from the basic ignition timing by the retard amount set in step S8, and fuel injection is resumed. As described above, the higher the water temperature, the greater the throttle opening is increased to improve the regeneration efficiency of the GPF 44, and the higher the water temperature, the greater the retard amount of the ignition timing is increased to suppress shock when returning from the fuel cut.

[0041] In the above embodiment, the temperature of the coolant is used as the temperature of the engine 10, but this is not limited to this and the temperature of the hydraulic oil may be used instead. In the above embodiment, the hybrid vehicle 1 is used as an example, but the vehicle may be an engine vehicle equipped with only an engine as a driving power source.

[0042] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as defined in the claims. [Explanation of symbols]

[0043] 1 Hybrid vehicle 10 Engine 15 Motor 16 Battery 18 Torque converter 20 Lock-up clutch 44 GPF (filter) 50 ECU (controller, acquisition unit, regeneration control unit, retard control unit)

Claims

1. an engine having a throttle valve; a filter for collecting exhaust particulates from the engine; a control device; The control device an acquisition unit that acquires the temperature of the engine; a regeneration control unit that increases an opening of the throttle valve as the acquired temperature increases when there is a request for regeneration of the filter, thereby executing regeneration control of the filter by cutting fuel; a retard control unit that increases a retard amount of the ignition timing at the time of recovery from the fuel cut as the acquired temperature increases when there is a request to recover from the fuel cut during execution of the regeneration control.

2. a motor provided on a power transmission path between the engine and drive wheels; a torque converter having a lock-up clutch provided on the power transmission path between the motor and the drive wheels, the regeneration control includes normal regeneration control in which the lock-up clutch is engaged to perform the fuel cut, and auxiliary regeneration control in which the lock-up clutch is released to perform the fuel cut while assisting the rotation of the engine by the motor, 2. The vehicle according to claim 1, wherein the regeneration control section increases the opening of the throttle valve in the auxiliary regeneration control to a degree greater than the opening of the throttle valve in the normal regeneration control.

3. 3. The vehicle according to claim 2, wherein the regeneration control section controls the rate of increase of the throttle valve opening relative to the temperature so that the rate of increase is greater in the normal regeneration control than in the auxiliary regeneration control.

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