Filter regeneration control device

Abstract

To provide a regeneration control device for a filter capable of easily starting and early completing forcible regeneration control.SOLUTION: A regeneration control device for a filter includes: a fuel supply control section that when a forcible regeneration request for burning particulate matters collected in the filter provided in an exhaust passage of an engine as a traveling power source of a vehicle during stop of the vehicle is made, while stopping fuel supply to at least one of a plurality of cylinders of the engine, supplies fuel to the cylinder other than the at least one cylinder; and a speed control section that when the forcible regeneration request is made, controls engine speed to become higher than that during an idling operation of the engine during stop of the vehicle without the forcible regeneration request.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] Forced regeneration control is known, which forcibly regenerates a filter while the vehicle is running under predetermined running conditions (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-029800 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to execute the above-mentioned forced regeneration control, the vehicle needs to be driven under predetermined driving conditions. This may make it difficult to start the forced regeneration control easily. Furthermore, it is preferable that such forced regeneration control can be completed as quickly as possible.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a filter regeneration control device that can easily start forced regeneration control and complete it quickly. [Means for solving the problem]

[0006] The object of the present invention is to provide a vehicle having an engine that is a power source for running a vehicle, and a fuel supply control unit that stops fuel supply to at least one of a plurality of cylinders of the engine while supplying fuel to the cylinders other than the at least one, when there is a request for forced regeneration to burn particulate matter trapped in a filter provided in an exhaust passage of the engine while the vehicle is stopped; While the vehicle is stopped a rotation speed control unit that controls the rotation speed of the engine when there is a request for forced regeneration to be higher than the rotation speed of the engine when idling and the vehicle is stopped without a request for forced regeneration. The vehicle is equipped with a motor as the driving power source, and the rotation speed control unit controls the rotation speed of the engine when there is a forced regeneration request while the vehicle is stopped to be higher than the rotation speed of the engine when there is no forced regeneration request and the motor is in regenerative operation while the vehicle is stopped, and includes an ignition timing control unit that controls the ignition timing of the cylinders other than the at least one when there is a forced regeneration request while the vehicle is stopped to be the same as the ignition timing when the engine is idling and there is no forced regeneration request while the vehicle is stopped. This can be achieved by a filter regeneration control device. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a filter regeneration control device that can easily start forced regeneration control and quickly complete it. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of a hybrid vehicle. [Figure 2] FIG. 2 is a schematic diagram of the engine. [Figure 3] FIG. 3 is a flowchart showing an example of control executed by the ECU. DETAILED DESCRIPTION OF THE INVENTION

[0011] [Hybrid vehicle configuration] FIG. 1 is a schematic diagram of a hybrid vehicle 1. In the hybrid vehicle 1, a K0 clutch 14, a motor 15, a wet clutch 18, and a transmission 19 are provided in this order in a power transmission path from an engine 10 to drive wheels 13. The engine 10 and the motor 15 are installed as a driving power source for the hybrid vehicle 1. The engine 10 is, for example, a V6 gasoline engine, but the number of cylinders is not limited thereto, and the engine 10 may be an in-line gasoline engine or a diesel engine. The K0 clutch 14, the motor 15, the wet clutch 18, and the transmission 19 are provided in a transmission unit 11. The transmission unit 11 and the left and right drive wheels 13 are drivingly connected via a differential 12.

[0012] The K0 clutch 14 is provided between the engine 10 and the motor 15 on the power transmission path. The K0 clutch 14 receives a supply of hydraulic pressure from a disengaged state and enters an engaged state, connecting the power transmission between the engine 10 and the motor 15. The K0 clutch 14 enters a disengaged state when the hydraulic pressure supply is stopped, and interrupts the power transmission between the engine 10 and the motor 15. The engaged state is a state in which both engagement elements of the K0 clutch 14 are connected and the engine 10 and the motor 15 are rotating at the same speed. The disengaged state is a state in which both engagement elements of the K0 clutch 14 are disengaged.

[0013] The motor 15 is connected to the battery 16 via an inverter 17. The motor 15 functions as a motor that generates driving force for the vehicle in response to power supplied from the battery 16, and 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.

[0014] The inverter 17 is controlled by an ECU (Electronic Control Unit) 100, which will be described later, and converts the DC voltage from the battery 16 into an AC voltage, or converts the AC voltage from the motor 15 into a DC voltage. In the case of power running in which the motor 15 outputs torque, the inverter 17 converts the DC voltage from the battery 16 into an AC voltage and adjusts the power supplied to the motor 15. In the case of regenerative running in which the motor 15 generates power, the inverter 17 converts the AC voltage from the motor 15 into a DC voltage and adjusts the power supplied to the battery 16.

[0015] The transmission 19 is a stepped automatic transmission that changes the gear ratio in multiple stages by changing the gear position, but is not limited to this and may be a continuously variable automatic transmission. The transmission 19 is provided between the motor 15 and the drive wheels 13 on the power transmission path. A wet clutch 18 is provided that receives a supply of hydraulic pressure and enters an engaged state to directly connect the motor 15 and the transmission 19.

[0016] 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 wet clutch 18, and the transmission 19 via the hydraulic control mechanism 22. The hydraulic control mechanism 22 is provided with hydraulic circuits for the K0 clutch 14, the wet clutch 18, and the transmission 19, as well as various hydraulic control valves for controlling the operating hydraulic pressures thereof. Note that a torque converter equipped with a lock-up clutch may be provided instead of the wet clutch 18.

[0017] The hybrid vehicle 1 is provided with an ECU 100 as a control device for the vehicle. The ECU 100 is an electronic control unit that includes a processing circuit that performs various arithmetic operations related to vehicle driving control, and a memory that stores control programs and data. The ECU 100 functionally realizes a fuel supply control unit, a rotation speed control unit, and an ignition timing control unit, which will be described in detail later.

[0018] The ECU 100 controls the operation of the engine 10 and the motor 15. Specifically, the ECU 100 controls the torque and rotation speed of the engine 10 by controlling the throttle opening, ignition timing, and fuel injection amount of the engine 10. The ECU 100 controls the rotation speed and torque of the motor 15 by controlling the inverter 17 to adjust the amount of power exchanged between the motor 15 and the battery 16. The ECU 100 also controls the operation of the K0 clutch 14, the wet clutch 18, and the transmission 19 through control of the hydraulic control mechanism 22.

[0019] The ECU 100 receives signals from an ignition switch 71, a crank angle sensor 72, a motor rotation speed sensor 73, an air flow meter 74, and an air-fuel ratio sensor 75. The crank angle sensor 72 detects the rotation speed of the crankshaft of the engine 10, i.e., the engine rotation speed. The motor rotation speed sensor 73 detects the rotation speed of the output shaft of the motor 15. The air flow meter 74 detects the amount of intake air of the engine 10. The air-fuel ratio sensor 75 detects the air-fuel ratio of the exhaust gas that has passed through the three-way catalyst 43.

[0020] The ECU 100 drives the hybrid vehicle in either an electric driving mode (hereinafter referred to as BEV (Battery Electric Vehicle) mode) or a hybrid driving mode (hereinafter referred to as HEV (Hybrid Electric Vehicle) mode). In the BEV mode, the ECU 100 disengages the K0 clutch 14 and drives the vehicle using power from the motor 15. In the HEV mode, the ECU 100 switches the K0 clutch 14 to an engaged state and drives the vehicle using power from at least the engine 10. The HEV mode includes a mode in which the vehicle drives using power from the engine 10 alone, and a mode in which the motor 15 is powered and the vehicle drives using both the engine 10 and the motor 15 as power sources.

[0021] The driving mode is switched based on the vehicle's required driving force, which is calculated from the vehicle speed and accelerator pedal position, and the SOC (State Of Charge), which indicates the amount of charge stored in the battery 16. For example, if the required driving force is relatively small and the SOC is relatively high, the BEV mode is selected. If the required driving force is relatively large or the SOC of the battery 16 is relatively low, the HEV mode is selected.

[0022] A forced regeneration request tool 200 that is manually operated by a vehicle mechanic at a car dealer, repair shop, or the like (hereinafter collectively referred to as "repair shop") is connected to the ECU 100 via wire or wireless. By manually operating the forced regeneration request tool 200, a forced regeneration request, which will be described later, is input to the ECU 100. The forced regeneration request tool 200 is, for example, a computer device equipped with an operation input unit and a display unit, and transmits control signals to the ECU 100 in accordance with operation input by the vehicle mechanic. The forced regeneration request tool 200 may also be configured to receive information on the progress of the work and the work results from the ECU 100.

[0023] [Engine outline] FIG. 2 is a schematic diagram of the engine 10. The engine 10 has a cylinder #1, a piston 31, a connecting rod 32, a crankshaft 33, an intake passage 35, an intake valve 36, an exhaust passage 37, and an exhaust valve 38. FIG. 2 shows only one of the four cylinders #1 to #4 of the engine 10. An air-fuel mixture is combusted in each of the cylinders #1 to #4. A piston 31 is accommodated in each of the cylinders #1 to #4 so as to be able to reciprocate, and is connected to the crankshaft 33, which is the output shaft of the engine 10, via a connecting rod 32. The connecting rod 32 converts the reciprocating motion of the piston 31 into the rotational motion of the crankshaft 33.

[0024] The intake passage 35 is connected to the intake ports of the cylinders #1 to #4 via intake valves 36. The exhaust passage 37 is connected to the exhaust ports of the cylinders #1 to #4 via exhaust valves 38. The intake passage 35 is provided with an air flow meter 74 and a throttle valve 40 that adjusts the amount of intake air.

[0025] A three-way catalyst 43 and a gasoline particulate filter (GPF) 44 are provided in the exhaust passage 37 from the upstream side. The three-way catalyst 43 contains a catalytic metal such as platinum (Pt), palladium (Pd), or rhodium (Rh), has oxygen storage capacity, and purifies NOx, HC, and CO.

[0026] The GPF 44 is a porous ceramic structure that captures exhaust particulate matter (hereinafter referred to as PM (Particulate Matter)) in the exhaust gas. The GPF 44 also supports a precious metal such as platinum. During regeneration control, this precious metal promotes the oxidation reaction of the accumulated PM. The GPF 44 is an example of a filter. If the engine 10 is a diesel engine, for example, a DPF (Diesel Particulate Filter) is provided instead of the GPF 44. An air-fuel ratio sensor 75 is provided downstream of the GPF 44 in the exhaust passage 37.

[0027] Each of the cylinders #1 to #4 is provided with an in-cylinder injection valve 41. The in-cylinder injection valve 41 injects fuel directly into the corresponding cylinder #1 to #4. Note that instead of or in addition to the in-cylinder injection valve 41, a port injection valve that injects fuel toward the intake port may be provided. Each of the cylinders #1 to #4 is provided with an ignition device 42 that ignites, by spark discharge, an air-fuel mixture of intake air introduced through the intake passage 35 and fuel injected by the in-cylinder injection valve 41.

[0028] [Control performed by ECU] FIG. 3 is a flowchart showing an example of control executed by the ECU 100. This control is repeatedly executed at predetermined intervals while the ignition is on. The ECU 100 determines whether or not a forced regeneration request is made by the forced regeneration request tool 200 described above while the hybrid vehicle 1 is stopped (step S1). If the answer is No in step S1, this control is terminated. If the answer is Yes in step S1, the ECU 100 executes forced regeneration control (step S2). The forced regeneration control is realized by controlling the K0 clutch 14 to a released state and executing one-cylinder fuel cut processing, rotation speed processing, and ignition timing processing, which will be described later. In this way, forced regeneration control can be easily started while the hybrid vehicle 1 is stopped. Step S2 is an example of processing executed by the fuel supply control unit, rotation speed control unit, and ignition timing control unit.

[0029] Next, the ECU 100 determines whether or not the forced regeneration is complete (step S3). For example, the ECU 100 may determine that the combustion of exhaust particulates trapped in the GPF 44 is complete and that the forced regeneration is complete when the differential pressure before and after the GPF 44 is equal to or less than a threshold value. If the answer is No in step S3, the processing from step S1 onwards is executed again. If the answer is Yes in step S3, the ECU 100 ends the forced regeneration control (step S4).

[0030] The forced regeneration control will now be described in detail. First, the one-cylinder fuel cut process will be described. When a forced regeneration request is made, the ECU 100 executes one-cylinder fuel cut process, which stops fuel supply to one of the four cylinders #1 to #4 of the engine 10 and supplies fuel to the other cylinders. For example, fuel supply to cylinder #1 is stopped, and the fuel injection amount and intake air amount are adjusted to the other cylinders #2 to #4 so that the air-fuel ratio is richer than the stoichiometric air-fuel ratio. As a result, excess fuel discharged from the cylinder controlled to a rich air-fuel ratio adheres to the GPF 44 and is burned in a lean atmosphere by the air discharged from the cylinder to which fuel supply is stopped. As a result, exhaust particulates deposited in the GPF 44 are burned, and the GPF 44 is regenerated.

[0031] For example, when there is a forced regeneration request, it is conceivable to stop fuel supply to all cylinders #1 to #4 and then restore fuel supply to all cylinders #1 to #4 when the engine speed drops below the return speed. In this case, combustion is not occurring in any of the cylinders while fuel supply is stopped, and the hybrid vehicle 1 is stopped. Therefore, there is no power to forcibly rotate the engine 10 from the outside, and the engine speed may drop even further below the return speed, resulting in a stall. In this embodiment, combustion in the engine 10 can be continued by executing a single-cylinder fuel cut process that stops fuel supply to any one cylinder as described above. This makes it possible to execute forced regeneration control while avoiding engine stalls while the hybrid vehicle 1 is stopped.

[0032] Next, the rotation speed processing will be described. When a forced regeneration request is made, the ECU 100 controls the engine rotation speed when there is a forced regeneration request to be higher than the rotation speed of the engine 10 during idling when there is no forced regeneration request and the hybrid vehicle 1 is stopped. The ECU 100 also controls the engine rotation speed when there is a forced regeneration request to be higher than the rotation speed of the engine 10 when there is no forced regeneration request and the hybrid vehicle 1 is stopped and the motor 15 is in regenerative operation. This ensures the amount of oxygen supplied to the GPF 44, promotes the combustion of exhaust particulates accumulated in the GPF 44, and enables the forced regeneration to be completed early.

[0033] Next, the ignition timing process will be described. When a forced regeneration request is made, the ECU 100 controls the ignition timing of each of cylinders #2 to #4, to which fuel is supplied during single-cylinder fuel cut processing, to the same ignition timing as when the engine 10 is idling and the hybrid vehicle 1 is stopped without a forced regeneration request. To promote the combustion of exhaust particulates accumulated in the GPF 44, it is conceivable to retard the ignition timing when a forced regeneration request is made compared to the ignition timing during the above-mentioned idle operation. However, the effect of retarding the ignition timing on the combustion speed of exhaust particulates is not as great as the effect on the combustion speed due to the increase in engine speed described above. Therefore, by controlling the ignition timing during forced regeneration to the same value as the ignition timing during the above-mentioned idle operation, forced regeneration control can be performed while minimizing complex control.

[0034] In the above embodiment, an example of a hybrid vehicle is shown having an engine 10 and a motor 15 as a power source for running, but the present invention is not limited to this. For example, the hybrid vehicle may have an engine and first and second motors as power sources for running, and may further have a planetary gear mechanism including a sun gear connected to the first motor, a ring gear connected to the drive wheels and the second motor, and a carrier connected to the engine. Alternatively, the hybrid vehicle may be an engine vehicle having only an engine as a power source for running.

[0035] In the above embodiment, the one-cylinder fuel cut control in which fuel supply to one of the plurality of cylinders #1 to #4 is stopped is described as an example, but the present invention is not limited to this. For example, the fuel cut control may be such that fuel is supplied to at least one cylinder while fuel supply to the remaining plurality of cylinders is stopped. For example, in a V-type engine in which GPFs corresponding to the left and right banks are provided, the fuel cut control may be executed for one of the plurality of cylinders in the left bank and one of the plurality of cylinders in the right bank.

[0036] 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]

[0037] 1 Hybrid vehicle 10 Engine 15 Motor 44 GPF (filter) 100 ECU (filter regeneration control device, fuel supply control unit, rotation speed control unit, ignition timing control unit)

Claims

[Claim 1] a fuel supply control unit that stops fuel supply to at least one of a plurality of cylinders of the engine while supplying fuel to the cylinders other than the at least one when there is a request for forced regeneration in which particulate matter trapped in a filter provided in an exhaust passage of the engine, which is a power source for driving the vehicle, is burned while the vehicle is stopped; a rotation speed control unit that controls the rotation speed of the engine when there is a forced regeneration request while the vehicle is stopped to be higher than the rotation speed of the engine during idling operation when there is no forced regeneration request and the vehicle is stopped, The vehicle is equipped with a motor as the driving power source, the rotation speed control unit controls the rotation speed of the engine when there is a forced regeneration request while the vehicle is stopped to be higher than the rotation speed of the engine when there is no forced regeneration request and the motor is operated in regenerative mode while the vehicle is stopped, A filter regeneration control device comprising an ignition timing control section that controls the ignition timing of the cylinders other than the at least one cylinder when there is a forced regeneration request while the vehicle is stopped to be the same as the ignition timing during idling of the engine when there is no forced regeneration request and the vehicle is stopped.

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