JP2024066861A - Vehicle control device - Google Patents

Abstract

[Problem] To provide a vehicle control device capable of executing both filter temperature increase control and regeneration control while ensuring drivability. [Solution] A control device for a vehicle including an engine as a driving power source, a filter that collects exhaust particulates from the engine, and a torque converter having a lock-up clutch provided on a power transmission path between the engine and drive wheels, the control device including a determination unit that determines whether there is a request to increase the temperature of the filter by retarding the ignition timing of the engine and a request to regenerate the filter by cutting fuel in the engine, and a control unit that, when there is a request to increase the temperature and a request to regenerate the filter, releases the lock-up clutch when the accelerator is on and executes the temperature increase control of the filter, and engages the lock-up clutch when the accelerator is switched from on to off after the temperature increase control is completed. [Selected Figure] Figure 3

Description

The present invention relates to a vehicle control device.

Filter temperature control may be performed by retarding the ignition timing in the engine. In this case, the lock-up clutch is released, thereby preventing engine vibrations caused by retarding the ignition timing from being transmitted to the drive wheels (see, for example, Patent Document 1). Filter regeneration control may be performed by cutting fuel in the engine. In this case, engaging the lock-up clutch of the torque converter transmits power from the drive wheels to the engine, suppressing a drop in engine speed and preventing engine stall (see, for example, Patent Document 2).

JP 2018-141445 A JP 2021-148097 A

The above patent documents do not disclose the case where both a temperature increase request and a regeneration request are made, and it is desirable to execute both temperature increase control and regeneration control while ensuring drivability.

The present invention aims to provide a vehicle control device that can perform both filter temperature increase control and regeneration control while ensuring drivability.

The above object can be achieved by a vehicle control device that includes an engine as a driving power source, a filter that collects exhaust particulates from the engine, and a torque converter having a lock-up clutch provided on a power transmission path between the engine and drive wheels, the vehicle control device including: a determination unit that determines whether there is a request to heat the filter by retarding the ignition timing of the engine and a request to regenerate the filter by cutting fuel in the engine; and a control unit that, when there is a request to heat the filter and a request to regenerate the filter, releases the lock-up clutch when the accelerator is on and executes temperature rise control of the filter, and engages the lock-up clutch when the accelerator is switched from on to off after completion of the temperature rise control.

The control unit may continue the temperature rise control if the accelerator is switched from on to off before the temperature rise control is completed.

The vehicle may also include a motor that is a driving power source provided on the power transmission path between the engine and the torque converter, and a battery that supplies and receives power between the motor.

The present invention provides a vehicle control device that can perform both filter temperature increase control and regeneration control while ensuring drivability.

FIG. 1 is a schematic diagram of a hybrid vehicle. FIG. 1 is a schematic configuration diagram of an engine. 4 is a flowchart illustrating a temperature rise control and a regeneration control.

[General configuration of hybrid vehicle]
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 driving power source. The engine 10 is a gasoline engine having multiple cylinders, but may be a diesel engine. A transmission unit 11 is provided in 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.

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

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 hydraulic pressure is applied, 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 starts until it is fully engaged.

The motor 15 is connected to the battery 16 via the 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 power to charge the battery 16 in response to power transmission from the engine 10 and the drive wheels 13. The power exchanged between the motor 15 and the battery 16 is adjusted by the inverter 17.

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 amplifying function. The automatic transmission 19 is a stepped transmission that switches the gear ratio in multiple stages. The torque converter 18 is provided between the motor 15 and the drive wheels 13 on the power transmission path. The automatic transmission 19 is provided between the torque converter 18 and the drive wheels 13 on the power transmission path. 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.

The LU clutch 20 is engaged when hydraulic pressure is applied, 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 release to engagement.

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 the K0 clutch 14, the torque converter 18, the automatic transmission 19, and the LU clutch 20, as well as various hydraulic control valves for controlling the operating hydraulic pressures thereof.

The hybrid vehicle 1 is provided with an ECU (Electronic Control Unit) 50 as a control device for the vehicle. The ECU 50 is an electronic control unit that includes a calculation processing circuit that performs various calculation processes related to the vehicle's driving control, and a memory that stores control programs and data. The ECU 50 is an example of a vehicle control device, and functionally realizes a determination unit and a control unit, which will be described in detail later.

Signals are input to the ECU 50 from an ignition switch 61, a crank angle sensor 62, an air flow meter 63, air-fuel ratio sensors 64 and 65, and an accelerator position 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 accelerator position sensor 66 detects the accelerator position operated by the accelerator pedal.

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 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.

The ECU 50 drives the hybrid vehicle 1 in either the motor driving mode or the hybrid driving mode. In the motor driving mode, the ECU 50 releases the K0 clutch 14 to rotate the drive wheels 13 with 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 with the power of at least one of the engine 10 and the motor 15. The motor driving mode is selected when there is sufficient charge remaining in the battery 16. The hybrid driving mode is selected when the battery 16 has a low charge remaining, when the vehicle speed exceeds the upper limit in the motor driving mode, or when rapid acceleration occurs.

[General configuration of engine]
2 is a schematic diagram of the engine 10. The engine 10 has 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.

The cylinder block 30 has a cylindrical bore 31. A piston 33 is accommodated in the bore 31 so that it can 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 due to the reciprocating motion of the piston 33.

The engine 10 is connected to the crankshaft 35, which is the output shaft, via a connecting rod 34. The connecting rod 34 and the crankshaft 35 form a crank mechanism that converts 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.

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.

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.

A three-way catalyst 43 and a gasoline particulate filter (GPF) 44 are provided in the exhaust passage 37. 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 collects exhaust particulates (hereinafter referred to as PM (Particulate Matter)) in the exhaust gas. The GPF 44 is an example of a filter. For example, if the engine 10 is a diesel engine, a diesel particulate filter (DPF) is provided instead of the GPF 44.

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.

Based on the detection signals of the above-mentioned sensors, the ECU 50 controls 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., thereby controlling the operation of the engine 10.

[Temperature increase control and regeneration control]
Next, a description will be given of an example of the temperature increase control and regeneration control of the GPF 44 executed by the ECU 50. Fig. 3 is a flow chart illustrating the temperature increase control and regeneration control of the GPF 44 in this embodiment. This control is repeatedly executed while the ignition is on.

The ECU 50 determines whether there is a request to heat the GPF 44 (step S1). If the answer is Yes in step S1, the ECU 50 determines whether there is a request to regenerate the GPF 44 (step S2). If the answer is Yes in step S1 and No in step S2, the ECU 50 releases the LU clutch 20 and executes temperature rise control of the GPF 44 (step S3). In the temperature rise control, ignition timing retardation processing is executed. The amount of exhaust heat increases due to the ignition timing retardation processing, and the temperature of the GPF 44 rises. In addition, because the LU clutch 20 is released, it is possible to avoid transmission of fluctuations in the combustion state of the engine 10 due to the ignition timing retardation processing to the drive wheels 13.

If step S1 is No, the ECU 50 determines whether or not there is a request to regenerate the GPF 44 (step S4). If steps S1 and S4 are No, this control ends. If step S1 is No and step S4 is Yes, the ECU 50 executes regeneration control (step S5). In regeneration control, fuel is cut off with the LU clutch 20 engaged. By cutting fuel, oxygen can be supplied to the GPF 44 to promote the combustion of accumulated PM. In addition, because fuel is cut off with the LU clutch 20 engaged, stalling of the engine 10 can be prevented.

If steps S1 and S2 are Yes, the ECU 50 determines whether the accelerator is on, i.e., whether the accelerator pedal is depressed, based on the detection value of the accelerator opening sensor 66 (step S6). If step S6 is Yes, the hybrid vehicle 1 can be considered to be accelerating, and the ECU 50 releases the LU clutch 20 and executes temperature rise control (step S7). Temperature rise control can be executed while satisfying the driver's acceleration request. Steps S1 and S2 are an example of processing executed by the determination unit.

Next, the ECU 50 executes step S6 again. If the answer is No in step S6, that is, if the accelerator is off and the hybrid vehicle 1 is decelerating, the ECU 50 judges whether or not the temperature rise control is completed (step S8). Specifically, it is determined that the temperature rise control is completed when the temperature of the GPF 44 is equal to or higher than a predetermined value. The temperature of the GPF 44 may be an estimated value calculated based on the engine speed or engine load, may be a detected value of a temperature sensor provided in the GPF 44, or may be calculated by other known methods. If the answer is No in step S8, step S7 is executed again.

If step S6 is No and step S8 is Yes, it is assumed that the hybrid vehicle 1 is decelerating and the temperature increase control is complete, and the ECU 50 engages the LU clutch 20 to execute regeneration control by fuel cut (step S9). Because fuel cut is executed when the accelerator is off, the impact on drivability can also be suppressed. Steps S6 to S9 are an example of processing executed by the control unit.

In this way, when there is both a temperature increase request and a regeneration request, temperature increase control and regeneration control can be executed continuously in response to accelerator on/off. This makes it possible to execute both temperature increase control and regeneration control while minimizing the impact on drivability.

As described above, the hybrid vehicle 1 is equipped with the motor 15 and the battery 16 in addition to the engine 10. For example, the battery 16 supplies power to the motor 15, which is the driving power source, and charges the motor 15 with the regenerative power. For this reason, the battery 16 is heavier than the battery mounted on the engine vehicle. In this way, the weight of the hybrid vehicle 1 is greater than that of an engine vehicle. As a result, the load on the engine 10 in the hybrid driving mode is greater than that of the engine of the engine vehicle. For this reason, the amount of PM emissions in the hybrid driving mode may be greater than that of an engine vehicle. For this reason, the hybrid vehicle 1 may be more frequently executed with temperature rise control and regeneration control than with an engine vehicle. The contents of the above embodiment are suitable for the hybrid vehicle 1, which is executed with high frequency with such temperature rise control and regeneration control. However, the contents of the above embodiment can also be applied to a control device for an engine vehicle that has only an engine as a driving power source.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as described in the claims.

Reference Signs List 1 Hybrid vehicle 10 Engine 15 Motor 16 Battery 18 Torque converter 20 Lock-up clutch 44 GPF (filter)
50 ECU (vehicle control device, determination unit, control unit)

Claims (3)

A control device for a vehicle including an engine as a driving power source, a filter for collecting exhaust particulates from the engine, and a torque converter having a lock-up clutch provided on a power transmission path between the engine and a drive wheel,
a determination unit that determines whether or not there is a request to increase the temperature of the filter due to a retardation process of the ignition timing of the engine and a request to regenerate the filter due to a fuel cut in the engine;
and a control unit that, when there is a temperature increase request and a regeneration request, releases the lock-up clutch when the accelerator is on and executes temperature increase control of the filter, and engages the lock-up clutch and executes regeneration control of the filter when the accelerator is switched from on to off after completion of the temperature increase control. The vehicle control device of claim 1, wherein the control unit continues the temperature rise control if the accelerator is switched from on to off before the temperature rise control is completed. a motor serving as a driving power source provided on a power transmission path between the engine and the torque converter;
3. The vehicle control device according to claim 1, further comprising: a battery for supplying and receiving electric power to and from the motor.

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