Control device for hybrid vehicle

Abstract

To provide a control device of a hybrid vehicle for suppressing the occurrence of a shock and the deterioration of emission accompanying the power generation start of an alternator.SOLUTION: A control device for a hybrid vehicle including an engine, an alternator configured to generate electric power by rotational power of the engine, a motor provided on a power transmission path from the engine to a drive wheel, and a clutch provided between the engine and the motor on the power transmission path, the control device comprising: A control device for a hybrid vehicle, comprising: a start control unit configured to, when there is a power generation request to the alternator in a state where the engine is stopped and the clutch is disengaged, slip the clutch to start the engine by the motor, and engage the clutch; and a power generation control unit configured to start power generation by the alternator after completion of torque replacement processing for increasing the torque of the engine and reducing the torque of the motor to zero or less.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] A hybrid vehicle is known that includes an engine, an alternator that generates electricity using the rotational power of the engine, a motor provided on a power transmission path from the engine to the drive wheels, and a clutch provided between the engine and the motor on the power transmission path (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2024-027458 Summary of the Invention [Problem to be solved by the invention]

[0004] When the alternator is requested to generate electricity while the engine is stopped and the clutch is disengaged, it is conceivable to start the engine and initiate power generation by the alternator. For example, it is conceivable to start the alternator generating electricity while cranking the engine with the motor via the clutch, and then engage the clutch. In this case, the alternator starts generating electricity before the engine combustion state stabilizes, which increases the load on the engine and may cause a shock when the clutch is engaged. Furthermore, this may worsen the combustion state at engine start, which may result in poor emissions.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a control device for a hybrid vehicle that suppresses the occurrence of shock and deterioration of emissions that accompany the start of power generation by an alternator. [Means for solving the problem]

[0006] The above object can be achieved by a control device for a hybrid vehicle that includes an engine, an alternator that generates electricity using the rotational power of the engine, a motor provided on a power transmission path from the engine to drive wheels, and a clutch provided between the engine and the motor on the power transmission path, the control device comprising: a start control unit that, when the engine is stopped and the clutch is released and there is a request for the alternator to generate electricity, executes engine start control to slip the clutch, start the engine using the motor, and engage the clutch; and a power generation control unit that starts generating electricity using the alternator after engagement of the clutch is completed, the combustion state of the engine is stabilized, and a torque switching process is completed in which the torque of the engine is increased and the torque of the motor is reduced to zero or below. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a control device for a hybrid vehicle that suppresses the occurrence of shock and deterioration of emissions that accompany the start of power generation by the alternator. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a hybrid vehicle. [Figure 2] 4 is a flowchart illustrating an example of alternator power generation control. [Figure 3] 4 is a timing chart illustrating an example of alternator power generation control. DETAILED DESCRIPTION OF THE INVENTION

[0009] [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, and a transmission 18 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 mounted as a driving source for running the hybrid vehicle 1. The engine 10 is, for example, a V6 gasoline engine, but the number of cylinders is not limited thereto, and it may be an in-line gasoline engine or a diesel engine. The engine 10 is provided with an alternator 10a. The K0 clutch 14, the motor 15, and the transmission 18 are provided in a transmission unit 11. The transmission unit 11 and the left and right drive wheels 13 are drivingly connected via a propeller shaft 12a and a differential gear 12. The transmission 18 includes a torque converter 19 and a gearbox 20.

[0010] 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 and changes from a released state to a slip state and then to an engaged state, connecting the power transmission between the engine 10 and the motor 15. The K0 clutch 14 changes to a released state when the hydraulic pressure supply is stopped, cutting off 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 rotation speed and the motor rotation speed are the same. The released state is a state in which both engagement elements of the K0 clutch 14 are separated. The slip state is a state in which there is a predetermined rotation speed difference between the engine 10 and the motor 15 and both engagement elements of the K0 clutch 14 are in sliding contact with each other.

[0011] 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 regenerative power to charge the battery 16 in response to power transmitted 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.

[0012] The inverter 17 is controlled by the ECU 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 regenerative power supplied to the battery 16.

[0013] The torque converter 19 is a fluid coupling with a torque amplification function. The transmission 20 is a stepped automatic transmission that switches the gear ratio in multiple stages by changing gear positions, but is not limited to this and may be a continuously variable automatic transmission. The transmission 20 is provided between the motor 15 and the drive wheels 13 on the power transmission path. The motor 15 and the transmission 20 are connected via the torque converter 19. The torque converter 19 is provided with a lock-up clutch 19a that receives hydraulic pressure and enters an engaged state to directly connect the motor 15 and the transmission 20.

[0014] 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 via the hydraulic control mechanism 22 to the K0 clutch 14, the torque converter 19, the transmission 20, and the lock-up clutch 19a.

[0015] The alternator 10a generates electricity by rotating the engine 10. The alternator 10a rotates the field coil in an excited state to generate induced electromotive force in the stator coil, and the induced current is converted to direct current by a rectifier to charge an auxiliary battery (not shown).

[0016] The hybrid vehicle 1 is provided with an ECU (Electronic Control Unit) 100 as a control device for the vehicle. The ECU 100 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 100 is an example of a control device, and functionally realizes a starting control unit and a power generation control unit, which will be described in detail later.

[0017] 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 power torque, regenerative torque, and rotation speed 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 lock-up clutch 19a, and the transmission 20 through control of the hydraulic control mechanism 22.

[0018] The ECU 100 is connected to an ignition switch 71, a crank angle sensor 72, and a motor rotation speed sensor 73. 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, i.e., the motor rotation speed.

[0019] The ECU 100 runs the hybrid vehicle in either a motor mode or a hybrid mode. In the motor mode, the ECU 100 disengages the K0 clutch 14 and runs the vehicle using the power of the motor 15. In the hybrid mode, the ECU 100 switches the K0 clutch 14 to an engaged state and runs the vehicle using at least the power of the engine 10.

[0020] [Alternator power generation control] 2 is a flowchart illustrating the alternator power generation control. This control is repeatedly executed at predetermined intervals with the engine 10 stopped, the K0 clutch 14 disengaged, and the ignition on. The ECU 100 determines whether or not there is a request for the alternator 10a to generate power (step S1). If the answer is No in step S1, this control ends.

[0021] If the answer is Yes in step S1, the ECU 100 executes start control of the engine 10 (step S2). Specifically, the start control of the engine 10 is a control for starting the engine 10 by cranking the engine 10 by the motor 15 via the K0 clutch 14 and engaging the K0 clutch 14 to start combustion in the engine 10. Step S2 is an example of a process executed by the start control unit.

[0022] Next, the ECU 100 determines whether or not the engagement of the K0 clutch 14 is complete (step S3). Specifically, when the engine rotation speed and the motor rotation speed match, it is determined that the engagement of the K0 clutch 14 is complete. If the determination in step S3 is No, this control ends.

[0023] If the answer to step S3 is Yes, the ECU 100 determines whether the combustion state of the engine 10 is stable (step S4). For example, if the engine speed is equal to or higher than the complete combustion speed and the rate of change of the engine speed is equal to or lower than a predetermined value, the combustion state is determined to be stable. If the answer to step S4 is No, this control ends.

[0024] If the answer is Yes in step S4, the ECU 100 determines whether or not the torque substitution process, which will be described in detail later, has been completed (step S5). For example, if the torque of the motor 15 becomes equal to or less than zero, it is determined that the torque substitution process has been completed. If the answer is No in step S5, this control ends. If the answer is Yes in step S5, the ECU 100 starts power generation by the alternator 10a (step S6). Step S6 is an example of a process executed by the power generation control unit.

[0025] Fig. 3 is a timing chart illustrating alternator power generation control. Fig. 3 shows the transitions of engine speed, motor speed, engine torque, motor torque, the state of the K0 clutch 14, and the power generation state of the alternator 10a. The motor speed and motor torque are indicated by dotted lines.

[0026] With the engine 10 stopped and the K0 clutch 14 in a disengaged state, the motor 15 is driven, increasing the motor speed and motor torque (time t1). As the motor torque increases (time t2) and the K0 clutch 14 enters a slip state, the rotation of the motor 15 increases the engine speed (time t3). The engine speed increases to the motor speed, and the K0 clutch 14 enters an engaged state (time t4). Thereafter, combustion in the engine 10 begins, and the combustion state stabilizes, increasing the engine torque (time t5). A torque substitution process is executed to reduce the motor torque to offset this increase in engine torque. The motor torque decreases to zero or less, completing the torque substitution process (time t6). After the torque substitution process is completed, the alternator 10a starts generating electricity (time t7).

[0027] As described above, the engagement of the K0 clutch 14 is completed, the combustion state of the engine 10 is stabilized, and the alternator 10a starts generating power after the torque switching process is completed. Therefore, the occurrence of shocks and deterioration of emissions associated with the start of power generation by the alternator 10a are suppressed.

[0028] FIG. 3 illustrates an example of alternator power generation control that is performed when the hybrid vehicle 1 is stopped. However, alternator power generation control can also be performed while the vehicle is traveling in motor mode. When alternator power generation control is performed while the vehicle is traveling in motor mode, combustion in the engine 10 begins with the K0 clutch 14 in a slip state, and the combustion state stabilizes after the K0 clutch 14 is engaged, after which the torque switching process is completed. After that, the alternator 10a begins generating power. In this case, the occurrence of shocks and deterioration of emissions associated with the start of power generation by the alternator 10a are suppressed. In this case, the traveling mode is switched from motor mode to hybrid mode.

[0029] 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]

[0030] 1 Hybrid vehicle 10 Engine 10a alternator 13 Drive wheels 14 K0 clutch (clutch) 15 Motor 100 ECU (controller, start control unit, power generation control unit)

Claims

[Claim 1] A control device for a hybrid vehicle including an engine, an alternator that generates electricity using rotational power of the engine, a motor provided on a power transmission path from the engine to drive wheels, and a clutch provided between the engine and the motor on the power transmission path, a start control unit that executes engine start control to slip the clutch and start the engine using the motor to engage the clutch when there is a request for power generation from the alternator in a state where the engine is stopped and the clutch is released; a power generation control unit that starts power generation by the alternator after the engagement of the clutch is completed, the combustion state of the engine is stabilized, and a torque switching process is completed in which the torque of the engine is increased and the torque of the motor is reduced to zero or less; A control device for a hybrid vehicle comprising:

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