Hybrid vehicle control device

Abstract

To provide a controller of a hybrid vehicle which can restrain decrease of drivability by preceding, while suppressing occurrence of shock in accompany with start control of an internal combustion engine, the start of the internal combustion engine in a situation that the start of the internal combustion engine is prioritized in comparison with the occurrence of the shock.SOLUTION: An electronic control device 90 of a hybrid vehicle 10 includes: an engine 12 and an electric motor MG as drive power source for travel; and a K0 clutch 20 which is arranged in a power transmission path PT between the engine 12 and the electric motor MG. The electronic control device thereof cancels, when (a) delay control which delays based on detection of a prescribed delay request set in advance for a prescribed period Td is executed against the start control which performs engagement of the K0 clutch 20 based on detection of a prescribed first start request set in advance to start the engine 12 by use of the electric motor MG, execution of the delay control based on detection of a prescribed second start request set in advance to execute the start control.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a control device for a hybrid vehicle that is provided with a friction engagement device disposed between an internal combustion engine and an electric motor in a power transmission path. [Background technology]

[0002] In a hybrid vehicle having a friction engagement device disposed between an internal combustion engine and an electric motor in a power transmission path, a method is known in which, when a start condition for the internal combustion engine is satisfied, the electric motor is caused to output a cranking torque and the friction engagement device is caused to be engaged to start the internal combustion engine, as described in Patent Document 1, for example. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-54165 Summary of the Invention [Problem to be solved by the invention]

[0004] In the method described in Patent Document 1, when start control for starting the internal combustion engine using an electric motor and other controls (for example, shift control of an automatic transmission or hydraulic learning control of a friction engagement device) are performed at the same time, the rotation speed of the rotating shaft on the electric motor side in the friction engagement device may fluctuate due to the other controls, and the rotation speed of the friction engagement device may not be synchronized at the appropriate time, resulting in a shock. Therefore, in such a case, it is possible to delay the execution of the start control of the internal combustion engine in order to suppress the occurrence of the shock. However, in a situation where it is desired to prioritize the start of the internal combustion engine over suppression of the occurrence of the shock, the delay in the start of the internal combustion engine may deteriorate drivability.

[0005] The present invention has been made against the background of the above circumstances, and its object is to provide a control device for a hybrid vehicle that can suppress the occurrence of shock associated with start-up control of an internal combustion engine, while prioritizing the starting of the internal combustion engine in situations where it is desired to prioritize the starting of the internal combustion engine over the occurrence of shock, thereby suppressing a decrease in drivability. [Means for solving the problem]

[0006] The gist of a first invention is a control device for a hybrid vehicle including an internal combustion engine and an electric motor as a driving force source for running, and a friction engagement device disposed between the internal combustion engine and the electric motor in a power transmission path between the internal combustion engine and drive wheels, the control device comprising: a control device for stopping execution of the delay control and executing the start control when a predetermined, preset second start request is detected, the control device being configured to engage the friction engagement device to start the internal combustion engine by the electric motor when a delay control is being executed when a predetermined, preset second start request is detected, the control device being configured to stop execution of the delay control and execute the start control when a predetermined, preset second start request is detected, the control device being configured to delay execution of the delay control when a predetermined, preset second start request is detected, the control device being configured to stop execution of the delay control and execute the start control when a predetermined, preset second start request is detected, the control device being configured to engage the friction engagement device to start the internal combustion engine by the electric motor when a delay control is being executed when a predetermined, preset first start request is detected, the control device being configured to delay execution of the delay control for a predetermined period of time when a predetermined, preset second start request is detected, the control device being configured to stop execution of the delay control and execute the start control when a predetermined, preset second start request is detected, the control device being configured to engage the friction engagement device to start the internal combustion engine by the electric motor when a predetermined, preset first start request is detected, the control device being configured to engage the friction engagement device to start the internal combustion engine by the electric motor ... engage the friction engagement device to start the internal combustion engine by the electric motor when a predetermined, preset first start request is detected, the control device being configured to engage the friction engagement device to start the internal combustion engine The predetermined first start request is any one of the following: a state of charge value of a battery that supplies and receives power to the electric motor is less than a start threshold value of the internal combustion engine; a required drive torque is greater than a range that can be covered by only the regenerative output of the electric motor in a BEV driving mode; and warming up of the internal combustion engine is required. The predetermined second start request is any one of an accelerator operation by the driver, a brake operation by the driver, and a shift operation by the driver. The point is that. Effect of the Invention

[0007] According to the hybrid vehicle control device of the first invention, Either the state of charge value of a battery that supplies and receives power to the electric motor is less than a start threshold value of the internal combustion engine, the required drive torque in the BEV driving mode is greater than the range that can be covered by the regenerative output of the electric motor alone, or the internal combustion engine needs to be warmed up. When a delay control is being executed to delay a start control for starting the internal combustion engine by engaging the friction engagement device, which is executed based on the detection of a predetermined preset first start request, for a predetermined period of time based on the detection of a predetermined preset delay request, Either an accelerator operation has been performed by the driver, a brake operation has been performed by the driver, or a shift operation has been performed by the driverThe execution of the delay control is stopped based on detection of a predetermined preset second start request, and the start control is executed. The delay control is executed to delay the start control for starting the internal combustion engine using an electric motor for a predetermined period based on detection of the predetermined delay request, thereby suppressing the occurrence of shocks associated with the start control of the internal combustion engine. However, when the delay control for delaying the start control of the internal combustion engine is executed and a predetermined second start request is detected that prioritizes the start of the internal combustion engine over the occurrence of shocks, the execution of the delay control of the internal combustion engine is stopped and the start control of the internal combustion engine is executed. As a result, while the occurrence of shocks associated with the start control of the internal combustion engine is suppressed, in a situation where the start of the internal combustion engine is desired to be prioritized over the occurrence of shocks, the start is prioritized, thereby suppressing a decrease in drivability. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram of a hybrid vehicle equipped with an electronic control device according to an embodiment of the present invention, and is also a functional block diagram showing essential parts of control functions for various controls in the hybrid vehicle. [Diagram 2] 2 is an example of a flowchart illustrating a control operation of the electronic control device shown in FIG. 1. [Diagram 3] 3 is an example of a time chart in which the flowchart of FIG. 2 is executed when hydraulic pressure learning control of the K0 clutch is executed while the vehicle is stopped and the driver operates the accelerator while the hydraulic pressure learning control is being executed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that in the following embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of the various parts are not necessarily drawn accurately. EXAMPLES

[0012] This is a schematic configuration diagram of a hybrid vehicle 10 (hereinafter simply referred to as "vehicle 10") equipped with an electronic control device 90 according to an embodiment of the present invention, and is also a functional block diagram showing the main control functions for various controls in vehicle 10.

[0013] The vehicle 10 includes an engine 12 and an electric motor MG, which are driving power sources for traveling, and a power transmission device 16 provided in a power transmission path PT between the engine 12 and driving wheels 14. The vehicle 10 is a hybrid vehicle.

[0014] The engine 12 is a well-known internal combustion engine. An electronic control device 90 (described later) controls an engine control device 50 including a throttle actuator, a fuel injection device, an ignition device, and the like provided in the vehicle 10, thereby controlling an engine torque Te [Nm] that is an output torque of the engine 12. The engine 12 corresponds to the "internal combustion engine" in the present invention.

[0015] The power transmission device 16 includes, in order from the engine 12 side, a damper 42, a K0 clutch 20, an electric motor connecting shaft 36, a torque converter 22, an automatic transmission 24, and the like, housed within a case 18 which is a non-rotating member attached to the vehicle body. The power transmission device 16 also includes a propeller shaft 28 connected to a transmission output shaft 26 which is an output rotating member of the automatic transmission 24, a differential gear 30 connected to the propeller shaft 28, a pair of drive shafts 32 connected to the differential gear 30, and the like.

[0016] The power transmission device 16 includes an engine connecting shaft 34 that connects the engine 12 and a damper 42. The damper 42 is a well-known damper device, such as a pendulum damper, that transmits the rotation of the engine 12 while absorbing pulsation of the engine 12.

[0017] The K0 clutch 20 is a clutch disposed between the engine 12 and the electric motor MG in the power transmission path PT between the engine 12 and the drive wheels 14. The electric motor connecting shaft 36 connects the K0 clutch 20 and the torque converter 22. The K0 clutch 20 is a hydraulic friction engagement device constituted by, for example, a multi-plate or single-plate clutch. The K0 clutch 20 switches between an engaged state, a released state, or a controlled state by changing the K0 torque Tk0 [Nm], which is the transmission torque capacity (the engagement force of the K0 clutch 20), of the K0 clutch 20 by the K0 oil pressure PRk0 [Pa], which is the adjusted oil pressure supplied from the hydraulic control circuit 56. Hereinafter, unless otherwise specified, the "engagement" of the K0 clutch 20 includes full engagement and half engagement (slip engagement).

[0018] In the vehicle 10, when the K0 clutch 20 is in an engaged state, the engine 12 and the torque converter 22 are connected to each other via the damper 42 and the K0 clutch 20 so as to be able to transmit power. On the other hand, when the K0 clutch 20 is in a released state, power transmission between the engine 12 and the torque converter 22 is interrupted. The K0 clutch 20 functions as a clutch that connects and disconnects the engine 12 and the electric motor MG. When the K0 clutch 20 is in an engaged state, one end of the electric motor connecting shaft 36 is connected to the engine 12 via the damper 42, and is thereby driven to rotate by the engine 12. The K0 clutch 20 corresponds to the "friction engagement device" in this invention.

[0019] The torque converter 22 is a well-known torque converter. The torque converter 22 includes a pump wheel 22a connected to the motor connecting shaft 36, a turbine wheel 22b connected to a transmission input shaft 38 that is an input rotating member of the automatic transmission 24, and a lock-up clutch 40 that directly connects the pump wheel 22a and the turbine wheel 22b. The torque converter 22 is a fluid-type power transmission device that transmits the driving force for traveling from each of the driving force sources for traveling (the engine 12, the electric motor MG) from the motor connecting shaft 36 to the transmission input shaft 38 via a fluid. The torque converter 22 is connected to the engine 12 via the K0 clutch 20 and a damper 42. The automatic transmission 24 is connected to the torque converter 22 and is provided in a transmission path between the torque converter 22 and the drive wheels 14 in the power transmission path PT. The torque converter 22 and the automatic transmission 24 each constitute a part of a power transmission path PT between a driving power source for traveling (the engine 12, the electric motor MG) and the driving wheels 14.

[0020] The electric motor MG is a rotating electric machine having a function as an electric motor that generates mechanical power from electric power and a function as a generator that generates electric power from mechanical power, and is a so-called motor generator. The electric motor MG is connected to a battery 54 provided in the vehicle 10 via an inverter 52 described later. The battery 54 is an electricity storage device that supplies and receives electric power to the electric motor MG. The electric motor MG controls the electric motor torque Tm [Nm], which is the output torque of the electric motor MG, by controlling the inverter 52 by an electronic control device 90 described later. For example, when the rotation direction of the electric motor MG is a positive rotation that is the same as the rotation direction when the engine 12 is in operation, the electric motor torque Tm is a powering torque when it is a positive torque on the acceleration side, and is a regenerative torque when it is a negative torque on the deceleration side. The electric power also means electric energy when there is no particular distinction. The power also means torque and force when there is no particular distinction.

[0021] The electric motor MG is connected to the electric motor connecting shaft 36 in the case 18 so as to be capable of transmitting power. In other words, the electric motor MG is connected to a transmission path between the K0 clutch 20 and the torque converter 22 in the power transmission path PT so as to be capable of transmitting power. In other words, the electric motor MG is connected to the torque converter 22 and the automatic transmission 24 so as to be capable of transmitting power without passing through the K0 clutch 20.

[0022] The automatic transmission 24 is disposed between the driving power source (engine 12 and electric motor MG) and the drive wheels 14 in the power transmission path PT, specifically between the electric motor MG and the drive wheels 14 in the power transmission path PT, and is a known planetary gear type automatic transmission including, for example, one or more planetary gear sets (not shown) and a plurality of gear shift engagement devices CB. The gear shift engagement devices CB are, for example, known hydraulic friction engagement devices. The gear shift engagement devices CB have their respective transmission torque capacities, or CB torques Tcb [Nm], changed by the CB hydraulic pressure PRcb [Pa], or regulated hydraulic pressure, supplied from the hydraulic control circuit 56, to switch between control states such as an engaged state and a disengaged state.

[0023] The automatic transmission 24 is a stepped transmission in which one of a plurality of gear stages (also called gear stages) with different speed ratios (also called gear ratios) γat (=AT input rotation speed Ni [rpm] / AT output rotation speed No [rpm]) is formed by engaging one of the engagement devices for shifting CB. The automatic transmission 24 switches the formed gear stages by switching the control state of a predetermined engagement device, which is an engagement device involved in shifting the automatic transmission 24 among the engagement devices for shifting CB, according to the driver's accelerator operation, the vehicle speed V [km / h], etc., by an electronic control device 90 described later. The AT input rotation speed Ni is the rotation speed of the transmission input shaft 38, and is the input rotation speed of the automatic transmission 24. The AT input rotation speed Ni is the same value as the turbine rotation speed Nt [rpm], which is the output rotation speed of the torque converter 22. The AT input rotation speed Ni can be expressed by the turbine rotation speed Nt. The AT output rotation speed No is the rotation speed of the transmission output shaft 26 and is the output rotation speed of the automatic transmission 24.

[0024] For example, in the shift control of the automatic transmission 24, a shift is performed by switching one of the shift engagement devices CB between an engaged state and a released state, that is, a so-called clutch-to-clutch shift is performed. Here, the shift engagement device CB that is switched from a released state to an engaged state in the clutch-to-clutch shift is referred to as an "engagement side engagement device CBcon," and the shift engagement device CB that is switched from an engaged state to a released state in the clutch-to-clutch shift is referred to as a "release side engagement device CBdis." In addition, the CB oil pressure PRcb supplied to the hydraulic actuator that controls the engagement / disengagement state of the engagement side engagement device CBcon is referred to as an "engagement side operating oil pressure Pcon[Pa]," and the CB oil pressure PRcb supplied to the hydraulic actuator that controls the engagement / disengagement state of the release side engagement device CBdis is referred to as a "release side operating oil pressure Pdis[Pa]."

[0025] The hydraulic control circuit 56 uses the hydraulic pressure of oil (hydraulic oil OIL) pumped from the MOP 58, which is a mechanical oil pump, or the EOP 60, which is an electric oil pump, as a source pressure to supply the necessary hydraulic oil OIL to each part in the case 18. For example, the hydraulic control circuit 56 is provided with a K0 solenoid valve SC for controlling the connection and disconnection of the K0 clutch 20, and four shift solenoid valves SL1 to SL4 for controlling the shifting of the automatic transmission 24 (hereinafter, referred to as "shift solenoid valves SL" unless otherwise specified). The K0 solenoid valve SC and the shift solenoid valve SL are, for example, well-known linear solenoid valves, and include an electromagnetic part that is a device that converts electrical energy into driving force by supplying a driving current to a solenoid, and a pressure regulating part that regulates the pressure of the hydraulic oil OIL by driving the electromagnetic part to generate hydraulic oil pressure.

[0026] By controlling the drive current of the K0 solenoid valve SC, the hydraulic pressure supplied to the hydraulic actuator that controls the connected / disconnected state of the K0 clutch 20 is adjusted to control the connected / disconnected state of the K0 clutch 20. For example, the K0 clutch 20 is put into a released state by turning off the drive current of the K0 solenoid valve SC (a state in which no drive current flows), and the K0 clutch 20 is put into an engaged state by turning on the drive current of the K0 solenoid valve SC (a state in which drive current flows).

[0027] By controlling the combination of on / off of each drive current of the shift solenoid valve SL, the hydraulic pressure supplied to each hydraulic actuator that controls the engagement / disengagement state of the shift engagement device CB provided in the automatic transmission 24 is adjusted. As a result, the automatic transmission 24 is put into a neutral state or a desired gear ratio γat is formed. The shift engagement device CB is, for example, a wet-type multi-plate hydraulic friction engagement device such as a brake or a clutch. For example, the command pressures of the engagement side hydraulic pressure Pcon and the release side hydraulic pressure Pdis in a clutch-to-clutch shift are controlled according to a shift time chart that is predetermined experimentally or by design so that the engagement speed, release speed, and engagement shock of the engagement side engagement device CBcon and the release side engagement device CBdis are within an allowable range.

[0028] In the power transmission device 16, when the K0 clutch 20 is engaged, the power output from the engine 12 is transmitted from the engine connecting shaft 34 to the driving wheels 14 via the K0 clutch 20, the electric motor connecting shaft 36, the torque converter 22, the automatic transmission 24, the propeller shaft 28, the differential gear 30, the drive shaft 32, etc. in this order. The power output from the electric motor MG is transmitted from the electric motor connecting shaft 36 to the driving wheels 14 via the torque converter 22, the automatic transmission 24, the propeller shaft 28, the differential gear 30, the drive shaft 32, etc. in this order, regardless of the control state of the K0 clutch 20.

[0029] The vehicle 10 includes a MOP 58, an EOP 60, a pump motor 62, and the like. The MOP 58 is connected to the pump impeller 22a, and is rotated and driven by a driving power source for traveling (the engine 12, the electric motor MG) to discharge hydraulic oil OIL used in the power transmission device 16. The pump motor 62 is a motor dedicated to the EOP for rotating and driving the EOP 60. The EOP 60 is rotated and driven by the pump motor 62 to discharge hydraulic oil OIL. The hydraulic oil OIL discharged by the MOP 58 and the EOP 60 is supplied to a hydraulic control circuit 56. The hydraulic control circuit 56 supplies a CB hydraulic pressure PRcb, a K0 hydraulic pressure PRk0, and the like, each of which is adjusted based on the hydraulic oil OIL discharged by the MOP 58 and / or the EOP 60.

[0030] The vehicle 10 includes an electronic control device 90. The electronic control device 90 includes a so-called microcomputer equipped with, for example, a CPU, RAM, ROM, an input / output interface, and the like, and the CPU executes various controls of the vehicle 10 by performing signal processing according to a program previously stored in the ROM while utilizing the temporary storage function of the RAM. The electronic control device 90 includes computers for engine control, electric motor control, hydraulic control, and the like as necessary. The electronic control device 90 corresponds to the "control device" in the present invention.

[0031] The electronic control device 90 receives various signals based on detection values ​​from various sensors provided in the vehicle 10 (e.g., engine rotation speed sensor 70, turbine rotation speed sensor 72, output rotation speed sensor 74, electric motor rotation speed sensor 76, accelerator opening sensor 78, throttle valve opening sensor 80, battery sensor 84, etc.) (e.g., engine rotation speed Ne [rpm] which is the rotation speed of the engine 12, turbine rotation speed Nt which is the same value as the AT input rotation speed Ni, AT output rotation speed No corresponding to the vehicle speed V, electric motor rotation speed Nm [rpm] which is the rotation speed of the electric motor MG, accelerator opening θacc [%] which is the driver's accelerator operation amount which indicates the magnitude of the driver's acceleration operation, throttle valve opening θth [%] which is the opening of the electronic throttle valve, battery temperature THbat [°C] of the battery 54, battery charge / discharge current Ibat [A], battery voltage Vbat [V], etc.).

[0032] The electronic control device 90 outputs various command signals (e.g., an engine control signal Se for controlling the engine 12, an electric motor control signal Sm for controlling the electric motor MG, a CB hydraulic control signal Sbc for controlling the gear shift engagement device CB, a K0 hydraulic control signal Sk0 for controlling the K0 clutch 20, an LU hydraulic control signal Slu for controlling the lock-up clutch 40, an EOP control signal Seop for controlling the EOP 60, etc.) to each device (e.g., an engine control device 50, an inverter 52, a hydraulic control circuit 56, a pump motor 62, etc.) provided in the vehicle 10.

[0033] The electronic control device 90 functionally comprises a hybrid control means, i.e., a hybrid control unit 92 , a clutch control means, i.e., a clutch control unit 94 , a shift control means, i.e., a shift control unit 96 , and a delay feasibility determination means, i.e., a delay feasibility determination unit 98 .

[0034] The hybrid control unit 92 functionally comprises an engine control means, i.e., an engine control unit 92a, that controls the operation of the engine 12, and an electric motor control means, i.e., an electric motor control unit 92b, that controls the operation of the electric motor MG via the inverter 52, and performs hybrid drive control using the engine 12 and the electric motor MG, etc., using these control functions.

[0035] The hybrid control unit 92 calculates the drive demand amount of the vehicle 10 by the driver, for example, by applying the accelerator opening θacc and the vehicle speed V to a drive demand amount map. The drive demand amount map is a map in which the relationship between the accelerator opening θacc, the vehicle speed V, and the drive demand amount is obtained in advance experimentally or by design and stored. The drive demand amount is, for example, the required drive torque Trdem [Nm] at the drive wheels 14. In other words, the required drive torque Trdem is the required drive power Prdem [W] at the vehicle speed V at that time. The drive demand amount can also be the required drive force Frdem [N] at the drive wheels 14, the required AT output torque at the transmission output shaft 26, or the like. In calculating the drive demand amount, the AT output rotation speed No, or the like, can be used instead of the vehicle speed V.

[0036] The hybrid control unit 92 outputs an engine control signal Se for controlling the engine 12 and an electric motor control signal Sm for controlling the electric motor MG so as to realize the required driving power Prdem, taking into consideration the transmission loss, the auxiliary load, the gear ratio γat of the automatic transmission 24, the chargeable electric power Win [W] and the dischargeable electric power Wout [W] of the battery 54, etc. The engine control signal Se is, for example, a command value for the engine power Pe [W], which is the power of the engine 12 that outputs the engine torque Te at the engine rotation speed Ne at that time. The electric motor control signal Sm is, for example, a command value for the power consumption Wm [W] of the electric motor MG that outputs the electric motor torque Tm at the electric motor rotation speed Nm at that time.

[0037] The chargeable power Win of the battery 54 is the maximum power that can be input, which specifies the limit on the input power of the battery 54, and indicates the input limit of the battery 54. The dischargeable power Wout of the battery 54 is the maximum power that can be output, which specifies the limit on the output power of the battery 54, and indicates the output limit of the battery 54. The chargeable power Win and dischargeable power Wout of the battery 54 are calculated by the electronic control device 90 based on, for example, the battery temperature THbat and the state of charge value SOC [%] of the battery 54 (the ratio of the amount of charge actually stored to a predetermined full charge capacity).

[0038] When the required drive torque Trdem can be satisfied only by the output of the electric motor MG, the hybrid control unit 92 sets the drive mode to the motor drive (=BEV drive) mode. In the BEV drive mode, the hybrid control unit 92 performs BEV (Battery Electric Vehicle) drive in which the vehicle runs by outputting drive force for driving only from the electric motor MG among the drive force sources for driving (engine 12, electric motor MG) when the K0 clutch 20 is in the disengaged state. On the other hand, when the required drive torque Trdem cannot be satisfied without using at least the output of the engine 12, the hybrid control unit 92 sets the drive mode to the engine drive mode, i.e., hybrid drive (=HEV drive) mode. In the HEV drive mode, the hybrid control unit 92 performs engine drive, i.e., HEV (Hybrid Electric Vehicle) drive in which the vehicle runs by outputting drive force for driving only from the engine 12 among the drive force sources for driving (engine 12, electric motor MG) when the K0 clutch 20 is in the engaged state. On the other hand, even if the required drive torque Trdem can be satisfied only by the output of the electric motor MG, the hybrid control unit 92 establishes the HEV driving mode when the state of charge value SOC of the battery 54 is less than a predetermined engine start threshold value or when warming up of the engine 12 or the like is required. The engine start threshold value is a predetermined threshold value for determining that the state of charge value SOC is at a value at which the engine 12 needs to be forcibly started to charge the battery 54. In this way, the hybrid control unit 92 switches between the BEV driving mode and the HEV driving mode by automatically stopping the engine 12 during HEV driving and restarting the engine 12 after the engine has stopped, starting the engine 12 during BEV driving, automatically stopping the engine 12 in a stopped state and restarting the engine 12 after the engine has stopped, based on the required drive torque Trdem, etc.

[0039] The engine control unit 92a controls the engine torque Te to realize a drive demand amount for the vehicle 10. The electric motor control unit 92b controls the electric motor torque Tm to realize a drive demand amount for the vehicle 10. Specifically, in the BEV driving mode, the electric motor control unit 92b controls the electric motor torque Tm to realize the required drive torque Trdem. In the HEV driving mode, the engine control unit 92a controls the engine torque Te to realize all or a part of the required drive torque Trdem, and the electric motor control unit 92b controls the electric motor torque Tm to compensate for the torque that is insufficient in the engine torque Te with respect to the required drive torque Trdem.

[0040] The hybrid control unit 92 further includes, functionally, a first start request determination means for determining whether to start the engine 12, that is, a first start request determination unit 92c, and a start control means for executing start control of the engine 12, that is, a start control unit 92d.

[0041] The first start request determination unit 92c determines whether or not a start of the engine 12 is requested by a predetermined first start request. That is, the first start request determination unit 92c detects the presence or absence of a first start request. For example, when the state of charge value SOC of the battery 54 is less than the engine start threshold, the first start request is detected.

[0042] The clutch control unit 94 executes K0 clutch hydraulic control for controlling the K0 clutch 20 so as to execute start control of the engine 12 based on the detection of the first start request by the first start request determination unit 92c. For example, the K0 clutch hydraulic control is a control for outputting a K0 hydraulic control signal Sk0 to the hydraulic control circuit 56 for controlling the K0 clutch 20 in a released state toward an engaged state so as to obtain a K0 torque Tk0 for transmitting a cranking torque Tcr, which is a torque for increasing the engine rotation speed Ne to the engine 12 side in order to crank the engine 12. "Cranking" refers to rotating the engine connecting shaft 34 connected to the engine 12 in order to start the engine 12 by outputting a cranking torque Tcr [Nm] from the electric motor MG and bringing the K0 clutch 20 into an engaged state. The K0 clutch command pressure PRk0_tgt is a command pressure (target value) of the K0 hydraulic pressure PRk0. For example, in starting control of the engine 12, the K0 clutch command pressure PRk0_tgt is controlled according to a K0 time chart that is determined in advance experimentally or by design so that the engagement speed and engagement shock of the K0 clutch 20 are within an allowable range.

[0043] The start control unit 92d controls the engine 12 and the electric motor MG to execute start control of the engine 12 based on the detection of the first start request by the first start request determination unit 92c. For example, the start control unit 92d outputs to the inverter 52 an electric motor control signal Sm for causing the electric motor MG to output the cranking torque Tcr in accordance with the switching of the K0 clutch 20 to the engaged state by the clutch control unit 94. That is, when starting the engine 12, the start control unit 92d outputs to the inverter 52 an electric motor control signal Sm for controlling the electric motor MG to output the cranking torque Tcr.

[0044] The engine 12 is cranked by the K0 clutch hydraulic control by the clutch control unit 94 and the output control of the cranking torque Tcr of the electric motor MG by the start control unit 92d. In this manner, the start control of the engine 12 is a control for engaging the K0 clutch 20 to start the engine 12 by the electric motor MG.

[0045] The start control unit 92d outputs an engine control signal Se for starting fuel supply, ignition, and the like to the engine control device 50 in conjunction with cranking of the engine 12 by the K0 clutch 20 and the electric motor MG based on detection of the first start request by the first start request determination unit 92c. That is, when starting the engine 12, the start control unit 92d outputs an engine control signal Se for controlling the engine 12 so that the engine 12 starts operating to the engine control device 50. In this way, the start control unit 92d executes start control of the engine 12 based on detection of the first start request by the first start request determination unit 92c.

[0046] For example, when starting the engine 12 during BEV driving, the start control unit 92d causes the electric motor MG to output an electric motor torque Tm equivalent to the cranking torque Tcr in addition to the electric motor torque Tm for BEV driving, i.e., the electric motor torque Tm that generates the required drive torque Trdem.

[0047] The shift control unit 96 judges whether or not to shift the automatic transmission 24 by using, for example, a shift map which is a predetermined relationship, and outputs a CB hydraulic control signal Sbc to the hydraulic control circuit 56 for executing shift control of the automatic transmission 24 as necessary. The shift map is a predetermined relationship having a shift line for judging whether or not to shift the automatic transmission 24 on a two-dimensional coordinate system having, for example, vehicle speed V and required driving torque Trdem as variables. In the shift map, the AT output rotation speed No or the like may be used instead of the vehicle speed V, and the required driving force Frdem, accelerator opening θacc, throttle valve opening θth or the like may be used instead of the required driving torque Trdem.

[0048] The shift phase (shift stage) of the automatic transmission 24 includes a torque phase and an inertia phase. The torque phase is a phase during the shift period (the period from the start of shift control to the end of shift control) of the automatic transmission 24 during which the output torque of the automatic transmission 24 changes. The inertia phase is a phase during the shift period of the automatic transmission 24 during which the turbine rotation speed Nt, which is equal to the rotation speed of the transmission input shaft 38, which is an input side rotating member in the automatic transmission 24, changes from a theoretical pre-shift turbine rotation speed Nt_pre [rpm] (theoretical turbine rotation speed Nt calculated from the gear ratio γat in the gear stage before the shift and the vehicle speed V) to a theoretical post-shift turbine rotation speed Nt_post [rpm] (theoretical turbine rotation speed Nt calculated from the gear ratio γat in the gear stage after the shift and the vehicle speed V). The torque phase is also a period during which the transmission torque capacity of the engaging side engaging device CBcon and the disengaging side engaging device CBdis changes.

[0049] When it is determined to execute start control of the engine 12 during a period when the shift control of the automatic transmission 24 is not being executed during BEV running, the start control unit 92d executes the start control of the engine 12 as described above. Also, when the shift control of the automatic transmission 24 is executed during a period when the start control of the engine 12 is not being executed by the start control unit 92d during BEV running, the shift control is executed by the shift control unit 96 as described above.

[0050] However, if hydraulic learning control of the K0 clutch 20 and start-up control of the engine 12 are executed simultaneously while the vehicle is stopped, the rotation speed of the electric motor MG connected to one side of the K0 clutch 20 may become unstable, which may reduce the learning accuracy of the hydraulic learning control. "Hydraulic learning control" refers to learning that corrects the hydraulic command value so that the engagement speed and engagement shock when switching a hydraulic friction engagement device such as the K0 clutch 20 from a released state to an engaged state are within an allowable range.

[0051] The delay possibility determination unit 98 functionally includes a delay request determination means, i.e., a delay request determination unit 98a, that makes a delay determination regarding the execution of the start control of the engine 12, and a second start request determination means, i.e., a second start request determination unit 98b, that makes a start determination for the engine 12. The delay possibility determination unit 98 determines whether or not to delay the execution of the start control of the engine 12, based on the determination result by the delay request determination unit 98a and the determination result by the second start request determination unit 98b.

[0052] When the hydraulic learning control of the K0 clutch 20 is being executed, the delay request determination unit 98a determines that there is a predetermined, preset delay request for delaying the execution of the start control of the engine 12. That is, the delay request determination unit 98a detects a delay request for delaying the start control of the engine 12. When the delay request determination unit 98a detects a delay request, the clutch control unit 94 and the start control unit 92d execute delay control for delaying the start control of the engine 12 based on the detection of the first start request for a predetermined period Td. That is, the clutch control unit 94 and the start control unit 92d execute delay control based on the detection of the delay request with priority over the start control of the engine 12. The predetermined period Td is a period until the motor rotation speed Nm is stable enough to allow learning so that the deterioration of the learning accuracy in the hydraulic learning control of the K0 clutch 20 is within an allowable range, and is, for example, a period until the fluctuation (magnitude of change) of the motor rotation speed Nm becomes stable and less than a predetermined value during the execution of the hydraulic learning control of the K0 clutch 20. The predetermined value is a value determined experimentally or by design in advance to determine whether the motor rotation speed Nm is in a steady state, and is, for example, a value close to zero. Preferably, the predetermined period Td is a period until a state in which the fluctuation of the motor rotation speed Nm is less than a predetermined value continues for a certain period in order to ensure that the motor rotation speed Nm is in a steady state.

[0053] The second start request determination unit 98b determines whether or not the start of the engine 12 is requested by a predetermined preset second start request. That is, the second start request determination unit 98b detects the presence or absence of a second start request. For example, when an accelerator-on operation is performed by the driver to change an accelerator pedal (not shown) from a released state (θacc=0) to a depressed state (θacc>0), the second start request is detected. When a delay control is performed to delay the start control of the engine 12, which is performed based on the detection of the first start request, for a predetermined period Td based on the detection of a delay request, the second start request determination unit 98b cancels the delay request detected by the delay request determination unit 98a based on the detection of the second start request.

[0054] When the delay request detected by the delay request determination unit 98a is maintained, the clutch control unit 94 executes delay control to delay the K0 clutch hydraulic control for a predetermined period Td. In addition, the start control unit 92d delays the output control of the cranking torque Tcr of the electric motor MG in accordance with the execution of the delay control of the K0 clutch hydraulic control by the clutch control unit 94. As a result, the start control of the engine 12 is delayed for the predetermined period Td.

[0055] When the delay request detected by the delay request determination unit 98a is released, the clutch control unit 94 stops the delay of the K0 clutch hydraulic control and executes the K0 clutch hydraulic control. Furthermore, the start control unit 92d executes output control of the cranking torque Tcr of the electric motor MG in accordance with the execution of the K0 clutch hydraulic control by the clutch control unit 94. Therefore, based on the detection of the second start request, the delay control that delays the execution of the start control of the engine 12 is stopped, and the start control is executed.

[0056] In this manner, when the delay control is being executed to delay the start control of the engine 12, which is executed based on the detection of the first start request, for a predetermined period Td based on the detection of the delay request, if the second start request is detected by the second start request determination unit 98b, the clutch control unit 94 and the start control unit 92d stop the execution of the delay control and execute the start control. In other words, based on the detection of the second start request, the start control of the engine 12 is executed with priority over the delay control.

[0057] Fig. 2 is an example of a flowchart illustrating the control operation of the electronic control device 90 shown in Fig. 1. The flowchart in Fig. 2 is repeatedly executed.

[0058] First, in step S10 (hereinafter, step will be omitted) corresponding to the function of the first start request determination unit 92c, it is determined whether or not a first start request has been made, i.e., whether or not a first start request has been detected. If the determination in S10 is positive, then in S20 corresponding to the function of the delay request determination unit 98a, it is determined whether or not a delay request has been made due to execution of control other than the start control of the engine 12, for example, hydraulic learning control of the K0 clutch 20, i.e., whether or not a delay request has been detected. If the determination in S10 is negative, the process returns.

[0059] If the determination in S20 is positive, then in S30, which corresponds to the function of the clutch control unit 94, it is determined whether or not the start time of the K0 clutch hydraulic control is within a predetermined period Td. If the determination in S20 is negative, then S60 is executed.

[0060] If the determination in S30 is positive, then in S40, which corresponds to the function of the second start request determination unit 98b, it is determined whether or not a second start request has been made, i.e., whether or not a second start request has been detected. If the determination in S30 is negative, then S60 is executed.

[0061] If the determination in S40 is positive, the delay request detected in S20 is released in S50, which corresponds to the function of the second start request determination unit 98b. If the determination in S20 is negative, if the determination in S30 is negative, or after S50 is executed, K0 clutch hydraulic control is executed in S60, which corresponds to the function of the clutch control unit 94. This executes start control of the engine 12. After execution of S60, the process returns. If the determination in S40 is negative, S30 is executed again.

[0062] Fig. 3 is an example of a time chart in which the hydraulic learning control of the K0 clutch 20 is executed while the vehicle is stopped, and the driver operates the accelerator while the hydraulic learning control is being executed, and the flow chart in Fig. 2 is executed. The horizontal axis in Fig. 3 is time t [ms].

[0063] Figure 3(a) shows a case where delay control is executed to delay the K0 clutch hydraulic control for a predetermined period Td by executing hydraulic learning control of the K0 clutch 20 when the vehicle is stopped, and Figure 3(b) shows a case where the delay request is released by the driver pressing the accelerator, and the hydraulic learning control of the K0 clutch 20 is executed earlier than in the case of Figure 3(a).

[0064] First, FIG. 3(a) will be described.

[0065] Before time t1, the accelerator opening θacc is zero, the engine rotation speed Ne is zero, the electric motor rotation speed Nm is zero, and the vehicle speed V is zero, so that the vehicle is in a stopped state.

[0066] At time t1, a learning condition signal indicating whether or not the conditions for implementing hydraulic learning control of the K0 clutch 20 are satisfied is switched from an OFF state to an ON state. When the learning condition signal is in the ON state, the conditions for implementing hydraulic learning control of the K0 clutch 20 are satisfied, and hydraulic learning control of the K0 clutch 20 is executed. When the learning condition signal is in the OFF state, the conditions for implementing hydraulic learning control of the K0 clutch 20 are not satisfied, and hydraulic learning control of the K0 clutch 20 is not executed. In addition, a delay request is detected based on the switching of the learning condition signal from the OFF state to the ON state, and delay control is executed to delay the start control of the engine 12. That is, the start of the K0 clutch hydraulic control is delayed until time t4, which will be described later.

[0067] At time t2 (>t1), a first start request is detected. Based on the detection of the first start request, a target motor rotation speed Nm_tgt, which is a target value of the motor rotation speed Nm, is increased. With a slight delay from the increase in the target motor rotation speed Nm_tgt, the actual motor rotation speed Nm is also increased. As the motor MG is driven to rotate, oil (hydraulic oil OIL) is pumped from the MOP 58 to the hydraulic control circuit 56.

[0068] At time t3 (> t2), the actual motor rotation speed Nm becomes stable and in a steady state. At time t4 (> t3), when the steady state of the actual motor rotation speed Nm continues for a while from time t3, the K0 clutch hydraulic control is started, at time t5 (> t4), the engine rotation speed Ne starts to increase, and at time t6 (> t5), the K0 clutch 20 is fully engaged and the engine rotation speed Ne and the motor rotation speed Nm become equal.

[0069] Next, FIG. 3(b) will be described.

[0070] Until time t2, it is the same as in Fig. 3(a). At time t10 (t2 < t10 < t4) before time t4 when the K0 clutch hydraulic pressure control starts in Fig. 3(a), when the driver performs an accelerator-on operation, the accelerator opening θacc starts to increase. As a result, the implementation condition of the hydraulic pressure learning control of the K0 clutch 20 becomes invalid, and the learning condition signal is switched from the on state to the off state. Also, due to the switching of the learning condition signal from the on state to the off state, the delay request is cancelled. By cancelling the delay request, the K0 clutch hydraulic pressure control starts at time t10. At time t11 (>t10), the increase in the engine rotation speed Ne starts, and at time t12 (>t11), the K0 clutch 20 is brought into a fully engaged state and the engine rotation speed Ne and the motor rotation speed Nm match.

[0071] According to this embodiment, when delay control is executed to delay the start control for engaging the K0 clutch 20 executed based on the first start request and starting the engine 12 by the motor MG by a predetermined period Td based on the detection of a delay request, the execution of the delay control is cancelled based on the detection of the second start request and the start control is executed. By executing the delay control to delay the start control for starting the engine 12 using the motor MG based on the detection of a delay request by a predetermined period Td, the occurrence of shock associated with the start control of the engine 12 is suppressed. However, when the delay control for delaying the start control of the engine 12 is being executed, if a second start request for prioritizing the start of the engine 12 over the occurrence of shock is detected, the execution of the delay control of the engine 12 is cancelled and the start control of the engine 12 is executed. Thereby, while suppressing the occurrence of shock associated with the start control of the engine 12, in a situation where the start of the engine 12 is to be prioritized over the occurrence of shock, the start is prioritized, suppressing a decrease in drivability.

[0072] According to this embodiment, (a) the first start request is detected when the state of charge value SOC of the battery 54 that supplies and receives power to the electric motor MG is less than the engine start threshold, and (b) the delay request is detected when the hydraulic learning control of the K0 clutch 20 is executed. As a result, when the start control of the engine 12 based on the first start request and the hydraulic learning control of the K0 clutch 20 are performed simultaneously and the second start request is not detected, the delay control that delays the start control of the engine 12 is executed, thereby suppressing the occurrence of shocks associated with the start control of the engine 12.

[0073] According to this embodiment, the second start request is detected when the driver operates the accelerator. In this manner, when delay control is being executed to delay the start control of the engine 12 due to a delay request, if the driver operates the accelerator, the second start request is detected and the execution of the delay control of the engine 12 is stopped. As a result, in a situation where the driver operates the accelerator and it is desired to prioritize starting the engine 12 over suppressing the occurrence of shocks associated with the start control of the engine 12, the start is prioritized, thereby suppressing a deterioration in drivability.

[0074] Although the embodiment of the present invention has been described in detail above with reference to the drawings, the present invention can be applied to other embodiments.

[0075] In the above embodiment, the first start request is detected when the state of charge value SOC of the battery 54 is less than the engine start threshold, the delay request is detected when the hydraulic learning control of the K0 clutch 20 is being executed, and the second start request is detected when the driver performs an accelerator operation in which the accelerator pedal (not shown) is depressed. However, the present invention is not limited to this embodiment. For example, the first start request may be detected in either of the following cases: (a) when the required driving torque Trdem is greater than the range that can be covered by the output of the electric motor MG alone in the BEV driving mode, or (b) when the engine 12 or the like needs to be warmed up. Also, the delay request may be detected in either of the following cases: (a) when the shift control of the automatic transmission 24 or (b) when the flow rate control of the hydraulic oil OIL that controls the operating state of the K0 clutch 20 in a stopped state is being executed. The delay request when the flow control of the hydraulic oil OIL is being executed is a request to delay the start control of the engine 12 until the flow rate of the circulating hydraulic oil OIL stabilizes at a predetermined flow rate value or more when the electric motor MG is rotated and driven in a stopped state to drive the MOP 58 and start circulating the hydraulic oil OIL. If the start control of the engine 12 is started before the flow rate of the circulating hydraulic oil OIL stabilizes, the K0 clutch hydraulic control for executing the start control of the engine 12 may operate unstably. The predetermined flow rate value is a flow rate value that is determined in advance by experiment or design so that the K0 clutch hydraulic control for executing the start control of the engine 12 operates stably. In addition, the predetermined second start request may be detected when, for example, (a) the driver performs a brake operation or (b) the driver performs a shift operation.

[0076] In the above embodiment, the automatic transmission 24 is of the planetary gear type, but the automatic transmission 24 in the present invention may be a stepped transmission of other configurations, such as a constant meshing parallel shaft type.

[0077] In the above embodiment, the torque converter 22 is used as the fluid transmission device, but the present invention is not limited to this embodiment. For example, other fluid transmission devices, such as a fluid coupling that does not amplify torque, may be used as the fluid transmission device instead of the torque converter 22. Also, the fluid transmission device does not necessarily have to be provided, and may be replaced with, for example, a starting clutch.

[0078] It should be noted that the above is merely an embodiment of the present invention, and the present invention can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art without departing from the spirit of the present invention. [Explanation of symbols]

[0079] 10: Hybrid vehicles 12: Engine (internal combustion engine) 14: Drive wheel 20: K0 clutch (friction engagement device) 24: Automatic transmission 90: Electronic control device (control device) MG: Electric motor PT: Power transmission path

Claims

[Claim 1] A control device for a hybrid vehicle including an internal combustion engine and an electric motor as a driving force source for traveling, and a friction engagement device disposed between the internal combustion engine and the electric motor in a power transmission path between the internal combustion engine and a drive wheel, When a delay control is being executed for delaying a start control for starting the internal combustion engine by engaging the friction engagement device based on detection of a predetermined preset first start request for a predetermined period based on detection of a predetermined delay request, the execution of the delay control is stopped based on detection of a predetermined preset second start request, and the start control is executed; The predetermined first start request is any one of the following: a state of charge value of a battery that supplies and receives power to the electric motor is less than a start threshold value of the internal combustion engine; a required drive torque in a BEV driving mode is greater than a range that can be covered by only the regenerative output of the electric motor; and warming up of the internal combustion engine is required. The predetermined second start request is any one of an accelerator operation by the driver, a brake operation by the driver, and a shift operation by the driver. A control device for a hybrid vehicle.

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