JP2022148900A - Control device of vehicle - Google Patents

Abstract

To provide a control device of a vehicle, which can suppress shock when an engine is stopped.SOLUTION: When an engine stop request for switching an engine 12 from an operating state to a stopping state is determined, a fuel cut for stopping fuel supply to the engine 12 after operating the engine 12 in a self-sustaining operation state for a prescribed period TE after engine torque Te is made into idle torque Teidl and a K0 clutch 20 is released. Therefore, engine speed Ne becomes stable as compared with engine speed Ne just after the K0 clutch 20 is released, for instance, by operating the engine 12 in the self-sustaining operation for the prescribed period TE after the K0 clutch 20 is released, so that shock when the engine 12 is stopped can be suppressed.SELECTED DRAWING: Figure 4

Description

TECHNICAL FIELD The present invention relates to a control device for a vehicle that cuts fuel after releasing a clutch when an engine stop request is determined, and relates to a technique capable of suppressing a shock when the engine stops.

(a) an engine; (b) an electric motor coupled to a power transmission path between the engine and drive wheels; and (c) a clutch provided between the engine and the electric motor; Control systems for vehicles equipped with are well known. For example, a vehicle control device described in Patent Document 1 is one of them. In the vehicle control device of Patent Document 1, for example, in order to switch from engine running (hybrid running) to motor running, when stopping the engine according to an engine stop command, the output torque of the engine is set to a predetermined idle torque. A fuel cut is disclosed in which the clutch is released from the engine and the fuel supply to the engine is promptly stopped when the torque capacity of the clutch becomes zero.

JP 2010-143307 A

By the way, in Patent Document 1, since the fuel cut is performed immediately after the clutch is released, the fuel cut is performed in a state where the engine rotation speed is not stable. could have caused a shock.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vehicle control system capable of suppressing shock when the engine stops.

The gist of the first invention is that: (a) an engine, an electric motor connected to a power transmission path between the engine and drive wheels so as to be able to transmit power, and a motor provided between the engine and the electric motor. and (b) when an engine stop request for switching the engine from an operating state to a stopped state is determined, the output torque of the engine is set to a predetermined value. To perform a fuel cut to stop the supply of fuel to the engine after operating the engine in a self-sustaining state for a predetermined period after setting the idle torque to release the clutch.

Further, the gist of the second invention is that in the first invention, the predetermined period is a period from after the clutch is released until the rotational speed of the engine becomes equal to or lower than a predetermined rotational speed. It is in being.

Further, the gist of the third invention is that in the first invention or the second invention, (a) whether or not the engine stop request is issued is determined at least during hybrid running in which driving force from the engine is used for running. (b) when the engine stop request is determined, the electric motor outputs a torque that decreases when the output torque of the engine is set to the idle torque.

The gist of the fourth invention is that in any one of the first to third inventions, (a) the vehicle is provided with a clutch hydraulic pressure for switching the control state of the clutch; (b) when the engine stop request is determined, the clutch hydraulic pressure is adjusted according to the output torque of the engine while the clutch is maintained in the engaged state; (c) when the output torque of the engine is reduced to the idle torque, the hydraulic control circuit reduces the clutch hydraulic pressure; To release the clutch by lowering the engagement maintaining oil pressure.

According to the vehicle control device of the first invention, (b) when an engine stop request for switching the engine from an operating state to a stopped state is determined, the output torque of the engine is set to a predetermined idle torque. After releasing the clutch, the engine is operated in a self-sustaining state for a predetermined period, and then a fuel cut is performed to stop the supply of fuel to the engine. Therefore, by operating the engine in the self-sustaining state for the predetermined period after the clutch is released, the rotation speed of the engine is reduced, for example, compared to the rotation speed of the engine immediately after the clutch is released. is stabilized, it is possible to suppress the shock when the engine stops.

According to the vehicle control device of the second aspect of the invention, the predetermined period is a period from after the clutch is released until the rotational speed of the engine becomes equal to or lower than a predetermined rotational speed. Therefore, it can be suitably determined that the rotational speed of the engine has stabilized after the clutch is released.

According to the vehicle control device of the third aspect of the invention, (a) the presence or absence of the engine stop request is determined during hybrid running in which at least the driving force from the engine drives, and (b) the engine stop request. is determined, the electric motor outputs a torque that decreases when the output torque of the engine is set to the idle torque. Therefore, fluctuations in the torque transmitted to the drive wheels can be suitably reduced when the engine is stopped.

According to the vehicle control device of the fourth aspect of the invention, (a) the vehicle is provided with a hydraulic control circuit for controlling clutch hydraulic pressure, which is hydraulic pressure for switching the control state of the clutch, and (b) the engine is stopped. When the request is determined, the clutch hydraulic pressure is set to the engagement maintaining hydraulic pressure for generating the torque capacity of the clutch corresponding to the output torque of the engine while the clutch is maintained in the engaged state. (c) when the output torque of the engine decreases to the idle torque, the hydraulic control circuit reduces the clutch hydraulic pressure from the engagement maintaining hydraulic pressure to release the clutch; Therefore, fluctuations in the torque transmitted to the driving wheels when the clutch is disengaged can be suitably reduced.

FIG. 1 is a diagram for explaining a schematic configuration of a vehicle to which the present invention is applied, and is a diagram for explaining main parts of a control function and a control system for various controls in the vehicle; FIG. 4 is a diagram for explaining a portion of the hydraulic control circuit related to hydraulic pressure supply to the K0 clutch, and a diagram for explaining a hydraulic pressure source that supplies hydraulic oil to the hydraulic control circuit; 4 is a time chart illustrating an example of each phase of the K0 clutch in the process of stopping the engine; 4 is a time chart illustrating an example of each phase of torque control of the engine and the electric motor in the process of stopping the engine; 4 is a flowchart for explaining a main part of the control operation of the electronic control unit, and is a flowchart for explaining the control operation for suppressing a shock when switching the engine from an operating state to a stopped state.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram for explaining a schematic configuration of a vehicle 10 to which the present invention is applied, and is a diagram for explaining control functions and main parts of a control system for various controls in the vehicle 10. As shown in FIG. In FIG. 1, a vehicle 10 is a hybrid vehicle including an engine 12 and an electric motor MG, which are driving force sources for running. The vehicle 10 also includes drive wheels 14 and a power transmission device 16 provided in a power transmission path between the engine 12 and the drive wheels 14 .

The engine 12 is a known internal combustion engine such as a gasoline engine or a diesel engine. The engine 12 is controlled by an electronic control device (control device) 90 to be described later. A certain engine torque Te is controlled.

The electric motor MG is a rotating electric machine having a function as a motor that generates mechanical power from electric power and a function as a generator that generates power from mechanical power, and is a so-called motor generator. Electric motor MG is connected to a battery 54 provided in vehicle 10 via an inverter 52 provided in vehicle 10 . The battery 54 is a power storage device that transfers electric power to and from the electric motor MG. In the electric motor MG, the MG torque Tm, which is the output torque of the electric motor MG, is controlled by controlling the inverter 52 by the electronic control unit 90, which will be described later. For example, when the rotation direction of the electric motor MG is the same rotation direction as the engine 12 is running, the MG torque Tm is a power running torque when the positive torque is on the acceleration side, and is a regenerative torque when the negative torque is on the deceleration side. be. Electric power is also synonymous with electrical energy when not specifically distinguished. The power is also synonymous with torque and force unless otherwise specified.

The power transmission device 16 includes a K0 clutch 20, a torque converter 22, an automatic transmission 24, etc. in a case 18, which is a non-rotating member attached to the vehicle body. K0 clutch 20 is a clutch provided between engine 12 and electric motor MG in a power transmission path between engine 12 and driving wheels 14 . Torque converter 22 is connected to engine 12 via K0 clutch 20 . Automatic transmission 24 is connected to torque converter 22 and is interposed in a power transmission path between torque converter 22 and drive wheels 14 . The power transmission device 16 includes a propeller shaft 28 connected to a transmission output shaft 26 which is an output rotating member of an automatic transmission 24, a differential gear 30 connected to the propeller shaft 28, and a gear 1 connected to the differential gear 30. A pair of drive shafts 32 and the like are provided. The power transmission device 16 also includes an engine connection shaft 34 that connects the engine 12 and the K0 clutch 20, an electric motor connection shaft 36 that connects the K0 clutch 20 and the torque converter 22, and the like.

The electric motor MG is connected to the electric motor connecting shaft 36 within the case 18 so as to be able to transmit power. In other words, the electric motor MG is connected to a power transmission path between the engine 12 and the drive wheels 14, particularly a power transmission path between the K0 clutch 20 and the torque converter 22 so that power can be transmitted. In other words, the electric motor MG is connected to the torque converter 22 and the automatic transmission 24 without the K0 clutch 20 so that power can be transmitted.

The torque converter 22 includes a pump impeller 22 a connected to an electric motor connecting shaft 36 and a turbine impeller 22 b connected to a transmission input shaft 38 which is an input rotating member of the automatic transmission 24 . Torque converter 22 is a hydrodynamic transmission device that transmits driving force from each of the driving force sources (engine 12, electric motor MG) from electric motor coupling shaft 36 to transmission input shaft 38 via fluid. The torque converter 22 includes an LU clutch 40 as a direct clutch that connects the pump impeller 22a and the turbine impeller 22b, that is, connects the electric motor connecting shaft 36 and the transmission input shaft 38. The LU clutch 40 is a known lockup clutch.

The automatic transmission 24 is a known planetary gear type automatic transmission including, for example, one or a plurality of sets of planetary gears (not shown) and a plurality of engagement devices CB. The engagement device CB is, for example, a known hydraulic friction engagement device. Each engagement device CB changes its torque capacity CB torque Tcb by CB hydraulic pressure PRcb which is regulated hydraulic pressure supplied from the hydraulic control circuit 56, so that the engagement device CB is in an engaged state or a disengaged state. is switched between operating states or control states.

In the automatic transmission 24, the gear ratio (also referred to as gear ratio) γat (=AT input rotation speed Ni/AT output rotation speed No) is established by engaging any one of the engagement devices CB. is a stepped transmission in which one of a plurality of gear stages (also referred to as gear stages) is formed. The automatic transmission 24 switches between gear stages according to the driver's accelerator operation, the vehicle speed V, and the like, by an electronic control unit 90, which will be described later. The AT input rotation speed Ni is the rotation speed of the transmission input shaft 38 and the input rotation speed of the automatic transmission 24 . The AT input rotation speed Ni has the same value as the turbine rotation speed Nt, which is the output rotation speed of the torque converter 22 . The AT input rotation speed Ni can be represented by the turbine rotation speed Nt. The AT output rotation speed No is the rotation speed of the transmission output shaft 26 and the output rotation speed of the automatic transmission 24 .

The K0 clutch 20 is a hydraulic friction engagement device composed of, for example, a multi-plate or single-plate clutch. The K0 clutch 20 changes its control state such as an engaged state and a released state by changing the K0 torque Tk0, which is the torque capacity of the K0 clutch 20, by the K0 hydraulic pressure PRk0, which is the hydraulic pressure supplied from the hydraulic control circuit 56. be done. The K0 oil pressure PRk0 is a clutch oil pressure for switching the control state of the K0 clutch 20 .

In the vehicle 10, when the K0 clutch 20 is engaged, the engine 12 and the torque converter 22 are connected so as to be able to transmit power. On the other hand, when the K0 clutch 20 is released, power transmission between the engine 12 and the torque converter 22 is cut off. Since the electric motor MG is connected to the torque converter 22, the K0 clutch 20 functions as a clutch that connects and disconnects the engine 12 with the electric motor MG.

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 connection shaft 34 to the K0 clutch 20, the electric motor connection shaft 36, the torque converter 22, the automatic transmission 24, The power is transmitted to the drive wheels 14 through the propeller shaft 28, the differential gear 30, the drive shaft 32, and the like. The power output from the electric motor MG is transmitted from the electric motor connecting shaft 36 to the torque converter 22, the automatic transmission 24, the propeller shaft 28, the differential gear 30, the drive shaft 32, etc. regardless of the control state of the K0 clutch 20. The power is transmitted to the driving wheels 14 through successively.

The vehicle 10 includes a mechanical oil pump MOP 58, an electric oil pump EOP 60, a pump motor 62, and the like. The MOP 58 is connected to the pump impeller 22a, and is driven to rotate by a driving force source (engine 12, electric motor MG) to discharge hydraulic oil OIL used in the power transmission device 16 (see FIG. 2 described later). . The pump motor 62 is a motor dedicated to the EOP 60 for rotating the EOP 60 . The EOP 60 is rotationally driven by a pump motor 62 to discharge hydraulic oil OIL (see FIG. 2 described later). Hydraulic oil OIL discharged from the MOP 58 and the EOP 60 is supplied to the hydraulic control circuit 56 . The hydraulic control circuit 56 supplies the CB hydraulic pressure PRcb, the K0 hydraulic pressure PRk0, etc., each of which is adjusted based on the hydraulic oil OIL discharged from the MOP 58 and/or the EOP 60 . That is, the hydraulic control circuit 56 controls, for example, the CB hydraulic pressure PRcb and the K0 hydraulic pressure PRk0 based on the hydraulic oil OIL discharged from the MOP 58 and/or the EOP 60 .

FIG. 2 is a diagram for explaining a portion of the hydraulic control circuit 56 related to hydraulic pressure supply to the K0 clutch 20, and is a diagram for explaining a hydraulic source for supplying hydraulic oil OIL to the hydraulic control circuit 56. As shown in FIG. In FIG. 2, the MOP 58 and the EOP 60 are provided in parallel due to the configuration of the oil passage through which the hydraulic oil OIL flows. Each of the MOP 58 and EOP 60 sucks up the hydraulic oil OIL that has flowed back to the oil pan 100 provided at the bottom of the case 18 through a strainer 102 that is a common suction port, and discharges it to each of the discharge oil passages 104 and 106. do. The discharge oil passages 104 and 106 are each connected to an oil passage provided in the hydraulic control circuit 56, for example, a line pressure oil passage 108 through which the line pressure PL flows. A discharge oil passage 104 through which hydraulic oil OIL is discharged from the MOP 58 is connected to a line pressure oil passage 108 via a MOP check valve 110 provided in the hydraulic control circuit 56 . A discharge oil passage 106 through which hydraulic oil OIL is discharged from the EOP 60 is connected to a line pressure oil passage 108 via an EOP check valve 112 provided in the hydraulic control circuit 56 .

The hydraulic control circuit 56 includes a line pressure oil passage 108, a MOP check valve 110, and an EOP check valve 112, as well as a regulator valve 114, a pressure regulation oil passage 116, a K0 supply oil passage 118, a PL solenoid valve SLT, It has a pressure regulating valve SK0, a K0 oil passage switching valve SCK0, and the like.

The regulator valve 114 regulates the line pressure PL based on the working oil OIL discharged by at least one of the MOP 58 and the EOP 60 . The PL solenoid valve SLT is, for example, a linear solenoid valve, and is an electronic control device that outputs a pilot pressure Pslt corresponding to the input torque Tinat to the automatic transmission 24 to the regulator valve 114 based on the modulator pressure PM. 90. The modulator pressure PM is a hydraulic pressure regulated to a constant value by a modulator valve (not shown) using, for example, the line pressure PL as a source pressure.

The pressure regulating valve SK0 is, for example, a linear solenoid valve, and is controlled by the electronic control unit 90 so as to regulate the SK0 oil pressure PRsk0, which is the hydraulic pressure supplied to the pressure regulating oil passage 116, using the line pressure PL as the source pressure. The SK0 oil pressure PRsk0 is a regulated oil pressure obtained by regulating the line pressure PL.

The K0 oil passage switching valve SCK0 is a switching valve whose oil passage is switched by actuation of a solenoid. Specifically, the K0 oil passage switching valve SCK0 cuts off the oil passage between the pressure regulating oil passage 116 and the K0 supply oil passage 118 when the solenoid is de-energized (=OFF). The oil passage is switched to connect the pressure oil passage 108 and the K0 supply oil passage 118 . On the other hand, the K0 oil passage switching valve SCK0 cuts off the oil passage between the line pressure oil passage 108 and the K0 supply oil passage 118 when the solenoid is energized (=ON), and the pressure regulation oil passage 116 is closed. and the K0 supply oil passage 118 are switched. The K0 supply oil passage 118 is an oil passage connected to the K0 clutch 20 and through which the K0 oil pressure PRk0 supplied to the K0 clutch 20 flows. Therefore, in the OFF state of the K0 oil passage switching valve SCK0, the line pressure PL is set to the K0 oil pressure PRk0. On the other hand, when the K0 oil passage switching valve SCK0 is on, the SK0 oil pressure PRsk0 is set to the K0 oil pressure PRk0. The K0 oil passage switching valve SCK0 is controlled by the electronic control unit 90 so as to switch between an OFF state and an ON state.

In this manner, the hydraulic control circuit 56 selectively supplies one of the line pressure PL, which is the original pressure of the K0 hydraulic pressure PRk0, and the SK0 hydraulic pressure PRsk0 obtained by regulating the line pressure PL, to the K0 clutch 20 as the K0 hydraulic pressure PRk0. supply.

The vehicle 10 further includes an electronic control unit 90 that includes a control unit for the vehicle 10 . The electronic control unit 90 includes, for example, a so-called microcomputer having a CPU, a RAM, a ROM, and an input/output interface. Various controls of the vehicle 10 are executed by performing signal processing. The electronic control unit 90 includes computers for engine control, electric motor control, hydraulic control, etc., as required.

The electronic control unit 90 includes various sensors provided in the vehicle 10 (for example, the engine rotation speed sensor 70, the turbine rotation speed sensor 72, the output rotation speed sensor 74, the MG rotation speed sensor 76, the accelerator opening sensor 78, the throttle valve Various signals based on detection values by the opening sensor 80, the brake switch 82, the battery sensor 84, the oil temperature sensor 86, etc. (e.g., the engine rotation speed Ne, which is the rotation speed of the engine 12, and the AT input rotation speed Ni) Turbine rotation speed Nt, AT output rotation speed No corresponding to vehicle speed V, MG rotation speed Nm, which is the rotation speed of electric motor MG, and accelerator opening θacc, which is the amount of accelerator operation by the driver representing the magnitude of acceleration operation by the driver. , the throttle valve opening θth which is the opening of the electronic throttle valve, the brake-on signal Bon which is a signal indicating that the brake pedal for operating the wheel brake is being operated by the driver, the battery temperature THbat of the battery 54, and A battery charging/discharging current Ibat, a battery voltage Vbat, a working oil temperature THoil which is the temperature of the working oil OIL in the hydraulic control circuit 56, etc.) are respectively supplied.

From the electronic control device 90, various command signals (for example, engine A control command signal Se, an MG control command signal Sm for controlling the electric motor MG, a CB hydraulic control command signal Scb for controlling the engagement device CB, and a pressure regulating valve as a command value for controlling the K0 clutch 20 An SK0 oil pressure command value Ssk0, which is a command value of the SK0 oil pressure PRsk0 for controlling SK0, an SCK0 command signal Ssck0 for controlling the on/off of the K0 oil passage switching valve SCK0, and an LU oil pressure control command for controlling the LU clutch 40 signal Slu, an EOP control command signal Seop for controlling the EOP 60, etc.) are respectively output.

The electronic control unit 90 includes hybrid control means, a hybrid control section 92 , clutch control means, a clutch control section 94 , and shift control means, a shift control section 96 , in order to realize various controls in the vehicle 10 .

The hybrid control unit 92 functions as engine control means, that is, an engine control unit 92a that controls the operation of the engine 12, and functions as an electric motor control unit, that is, an electric motor control unit 92b that controls the operation of the electric motor MG via the inverter 52. , and the hybrid drive control by the engine 12 and the electric motor MG is executed by these control functions.

The hybrid control unit 92 calculates the amount of driving demand for the vehicle 10 by the driver, for example, by applying the accelerator opening θacc and the vehicle speed V to a driving demand amount map. The required drive amount map is a relationship that is experimentally or design-experimentally obtained and stored, that is, a predetermined relationship. The required drive amount is, for example, the required drive torque Trdem at the drive wheels 14 . The required driving torque Trdem [Nm] is, in other words, the required driving power Prdem [W] at the vehicle speed V at that time. As the required driving amount, the required driving force Frdem [N] at the driving wheels 14, the required AT output torque at the transmission output shaft 26, and the like can be used. In the calculation of the drive demand amount, the AT output rotation speed No or the like may be used instead of the vehicle speed V. FIG. A hybrid control unit 92 generates an engine control command signal Se for controlling the engine 12 and an electric motor and an MG control command signal Sm for controlling the MG.

The hybrid control unit 92 sets the driving mode to the motor driving (=EV driving) mode when the required drive torque Trdem can be covered only by the output of the electric motor MG. In the EV traveling mode, the hybrid control unit 92 performs EV traveling in which driving force is output only from the electric motor MG of the driving force sources (the engine 12 and the electric motor MG) when the K0 clutch 20 is released. On the other hand, when the required drive torque Trdem cannot be met without using at least the output of the engine 12, the hybrid control unit 92 sets the running mode to the engine running mode, that is, the hybrid running (=HV running) mode. In the HV running mode, the hybrid control unit 92 outputs the driving force from at least the engine 12 of the driving force sources (the engine 12 and the electric motor MG) in the engaged state of the K0 clutch 20 to run the engine running, that is, the HV running. I do. On the other hand, even if the required drive torque Trdem can be covered only by the output of the electric motor MG, the hybrid control unit 92, when charging the battery 54 or warming up the engine 12 or the like, Establish the HV running mode.

The clutch control unit 94 supplies the line pressure PL to the K0 clutch 20 by turning off the K0 oil passage switching valve SCK0 in the operating state of the engine 12 in which the K0 clutch 20 is in the fully engaged state, such as the HV drive mode. , the SCK0 command signal Ssck0 is output to control the hydraulic control circuit 56. At this time, the clutch control unit 94 adjusts the SK0 oil pressure command values Ssk0 and SCK0 so that the line pressure PL is supplied to the K0 clutch 20 in a state where the value of the SK0 oil pressure PRsk0 by the pressure regulating valve SK0 is zero [kPa]. The hydraulic control circuit 56 may be controlled by outputting the command signal Ssck0. On the other hand, in the stopped state of the engine 12 in which the K0 clutch 20 is in the completely released state as in the EV driving mode, the clutch control unit 94 sets the value of the SK0 oil pressure PRsk0 by the pressure regulating valve SK0 to zero. The SK0 oil pressure command value Ssk0 and the SCK0 command signal Ssck0 are output to control the oil pressure control circuit 56 so that the SK0 oil pressure PRsk0 is supplied to the K0 clutch 20 by turning on the K0 oil passage switching valve SCK0.

The hybrid control unit 92 determines whether there is an engine start request, which is a request to start the engine 12 to switch the control state of the engine 12 from the stopped state to the operating state. For example, the hybrid control unit 92 determines whether or not the required driving torque Trdem has increased beyond the range that can be covered by the output of the electric motor MG alone, or whether or not the engine 12 or the like needs to be warmed up, during the EV running mode. Alternatively, it is determined whether or not there is an engine start request based on whether or not charging of the battery 54 is required.

When the hybrid control unit 92 determines that there is an engine start request, the clutch control unit 94 transmits to the engine 12 the torque necessary for cranking the engine 12, which is the torque for increasing the engine rotational speed Ne. SK0 oil pressure command value Ssk0 and The SCK0 command signal Ssck0 is output to the hydraulic control circuit 56 . In this embodiment, the torque required for cranking the engine 12 is referred to as required cranking torque Tcrn.

When the hybrid control unit 92 determines that there is an engine start request, the hybrid control unit 92 controls the electric motor MG to output the necessary cranking torque Tcrn in accordance with the switching of the K0 clutch 20 to the engaged state by the clutch control unit 94. MG control command signal Sm is output to inverter 52 . Further, when the hybrid control unit 92 determines that there is an engine start request, the hybrid control unit 92 interlocks with the cranking of the engine 12 by the K0 clutch 20 and the electric motor MG, and performs engine control for starting fuel supply, engine ignition, and the like. A command signal Se is output to the engine control device 50 .

After the engine 12 has been started by the hybrid control unit 92 and the switching of the K0 clutch 20 to the fully engaged state has been completed, the clutch control unit 94 switches the K0 oil passage switching valve SCK0 from the ON state to the OFF state. Then, the SCK0 command signal Ssck0 for supplying the line pressure PL to the K0 clutch 20 is output to the hydraulic control circuit 56 . Thereafter, the clutch control unit 94 preferably outputs to the hydraulic control circuit 56 the SK0 hydraulic pressure command value Ssk0 for setting the value of the SK0 hydraulic pressure PRsk0 to zero.

The hybrid control unit 92 determines whether there is an engine stop request, which is a request to stop the engine 12 to switch the control state of the engine 12 from the operating state to the stopped state. For example, the hybrid control unit 92 determines that the required driving torque Trdem is within a range that can be covered only by the output of the electric motor MG during the HV driving mode, ie, the hybrid driving mode, and the warm-up of the engine 12 and the like is unnecessary, and the battery 54 is charged. is unnecessary, it is determined whether there is an engine stop request.

When the hybrid control unit 92 determines that there is an engine stop request, that is, when it determines that there is an engine stop request, the hybrid control unit 92 gradually decreases the engine torque Te to bring the engine 12 into an idling state, that is, an idle torque Teidl, which will be described later. An engine control command signal Se is output to the engine control device 50 . After that, the hybrid control unit 92 performs a fuel cut (=FC) to stop the supply of fuel to the engine 12 after the K0 clutch 20 is switched to a completely released state by the clutch control unit 94 as will be described later. An engine control command signal Se for execution is output to the engine control device 50 .

When the hybrid control unit 92 determines that there is an engine stop request, the clutch control unit 94 switches the K0 oil passage switching valve SCK0 from the OFF state to the ON state during the transition in which the engine torque Te is gradually reduced. The SCK0 command signal Ssck0 for supplying the SK0 oil pressure PRsk0 to the K0 clutch 20 is output to the oil pressure control circuit 56, and the value of the SK0 oil pressure PRsk0 is gradually decreased from the value at which the K0 clutch 20 is engaged to zero. SK0 hydraulic pressure command value Ssk0 for switching 20 to the completely released state is output to the hydraulic control circuit 56 .

The shift control unit 96 performs shift determination for the automatic transmission 24 using, for example, a shift map having a predetermined relationship, and outputs a CB hydraulic control command signal for executing shift control of the automatic transmission 24 as necessary. Scb is output to the hydraulic control circuit 56 . The shift map is a predetermined relationship having a shift line for judging the shift of the automatic transmission 24 on two-dimensional coordinates having, for example, the vehicle speed V and the required driving torque Trdem as variables. In the shift map, the AT output rotational speed No may be used instead of the vehicle speed V, and the required driving force Frdem, the accelerator opening θacc, the throttle valve opening θth, etc. may be used instead of the required driving torque Trdem. can be

Here, since the control state of the K0 clutch 20 is controlled when the engine 12 is stopped, a plurality of progress stages, ie, phases, are defined for each control state of the K0 clutch 20 that is switched during the process of stopping the engine 12. there is

FIG. 3 is a time chart illustrating an example of each phase of the K0 clutch 20 in the process of stopping the engine 12. As shown in FIG. In FIG. 3, "K0 control phase" indicates the transition state of each phase of the K0 clutch 20 during the engine 12 stopping process. These phases are "stop K0 standby", "standby before K0 pressure regulation", "pressure regulation before K0 release", "K0 release transition SW", "K0 complete release transition SW", "after K0 release SW", "K0 complete release" and the like are defined. "... SW" indicates "... sweep".

In FIG. 3, at time t1, the stop control request flag is switched from OFF (=OFF) to ON (=ON) as it is determined that there is an engine stop request during HV driving mode, ie, hybrid driving. , indicates the point in time when the engine stop control for stopping the engine 12 in the operating state is started.

After the start of the engine stop control, the "standby for stop K0" phase (see time t1-t2) is executed. The "stop K0 standby" phase prepares for switching the K0 oil passage switching valve SCK0 from the OFF state to the ON state after the start of the engine stop control, that is, for switching from the line pressure PL of the K0 oil pressure PRk0 to the SK0 oil pressure PRsk0. In order to output the SK0 oil pressure command value Ssk0 for securing the K0 torque Tk0 corresponding to the engine torque Te in advance, the K0 oil pressure PRk0 is set to the line pressure PL until the engine torque Te decreases to the predetermined engine torque Tef. , the SK0 oil pressure command value Ssk0 is output to set the SK0 oil pressure PRsk0 to the EV steady-state K0 oil pressure PRk0ev while ensuring engagement of the K0 clutch 20 . The EV steady-state K0 oil pressure PRk0ev is the SK0 oil pressure PRsk0 in the EV travel mode, and the SK0 oil pressure PRsk0 is zero [kPa].

The SK0 oil pressure command value Ssk0 for ensuring the K0 torque Tk0 corresponding to the engine torque Te is set to the state where the K0 clutch 20 is maintained in the engaged state when the K0 oil pressure PRk0 is set to the SK0 oil pressure PRsk0. is the SK0 oil pressure command value Ssk0 as the engagement maintaining oil pressure PRk0c for generating the K0 torque Tk0 corresponding to the engine torque Te. The engine torque Te when the engagement maintaining oil pressure PRk0c is set is, for example, a value obtained by multiplying the actual engine torque Ter (see the thick solid line), which is the actual value of the engine torque Te, by the safety factor SF (see the long dashed line). is used. Specifically, the value obtained by multiplying the actual engine torque Ter by the safety factor SF is defined as the required K0 torque Tk0d (see the thin solid line), which is the required value of the K0 torque Tk0. The total K0 oil pressure PRk0 obtained by adding the equivalent of the K0 oil pressure PRk0 that generates the K0 torque Tk0d is set as the engagement maintaining oil pressure PRk0c. The pack end pressure of the K0 clutch 20 is the K0 oil pressure PRk0 in the so-called packing completion state in which the pack clearance of the K0 clutch 20 is closed. This is the K0 oil pressure PRk0 for keeping the state where Tk0 is not generated. The K0 clutch 20 generates the K0 torque Tk0 by further increasing the K0 oil pressure PRk0 from the packing completion state. The safety factor SF is a value greater than 1, and is a predetermined value that facilitates maintaining the engaged state of the K0 clutch 20 with respect to the actual engine torque Ter within a range in which the engagement maintaining oil pressure PRk0c is not excessively increased. value. The actual engine torque Ter is, for example, an estimated value of the engine torque Te calculated by applying the engine rotation speed Ne and the throttle valve opening θth to a predetermined engine torque map.

The predetermined engine torque Tef is a predetermined threshold that can suppress or prevent hydraulic vibration in the pressure regulating valve SK0 when the engagement maintaining hydraulic pressure PRk0c is output. The predetermined engine torque Tef may be a threshold value compared with the actual engine torque Ter, or may be a threshold value compared with a value obtained by multiplying the actual engine torque Ter by a safety factor SF.

In the "stop K0 standby" phase, when the engine torque Te decreases to a predetermined engine torque Tef, the phase is shifted to the "pre-K0 pressure adjustment standby" phase (see time t2-time t3). In the "standby before K0 pressure adjustment" phase, the K0 oil pressure PRk0 is set to the line pressure PL until the pressure adjustment oil passage 116 to which the SK0 oil pressure PRsk0 is supplied is filled with the hydraulic oil OIL, and the K0 clutch 20 is engaged. , SK0 oil pressure command value Ssk0 for setting the SK0 oil pressure PRsk0 to the engagement maintaining oil pressure PRk0c in preparation for switching from the line pressure PL of the K0 oil pressure PRk0 to the SK0 oil pressure PRsk0. Therefore, until the "standby before K0 pressure adjustment" phase, the actual K0 torque Tk0r (see the short dashed line) is generated by the K0 oil pressure PRk0 set to the line pressure PL.

After the start of the "standby before K0 pressure regulation" phase, when a predetermined filling time TMfil for filling the pressure regulation oil passage 116 with hydraulic oil OIL has passed, the "pressure regulation before K0 release" phase (time t3 - see time t4). In the "pre-K0 release pressure adjustment" phase, the SCK0 command signal Ssck0 is output to switch the K0 oil passage switching valve SCK0 from the off state to the on state, the K0 oil pressure PRk0 is switched from the line pressure PL to the SK0 oil pressure PRsk0, and the SK0 oil pressure PRsk0 is switched. This is the phase for outputting the SK0 oil pressure command value Ssk0 as the engagement maintaining oil pressure PRk0c. At time t3, the SCK0 command signal Ssck0 is switched from a non-energization (OFF) signal in which the solenoid of the K0 oil passage switching valve SCK0 is de-energized to an energization (ON) signal in which the solenoid of the K0 oil passage switching valve SCK0 is energized. That is, the SK0 switching start time PTstsk0, which is the time to start switching from the line pressure PL of the K0 oil pressure PRk0 to the SK0 oil pressure PRsk0. In the "pre-K0 release pressure adjustment" phase, the actual K0 torque Tk0r is reduced toward the required K0 torque Tk0d by the SK0 oil pressure PRsk0, that is, the K0 oil pressure PRk0 set to the engagement maintaining oil pressure PRk0c. The "pre-K0 release pressure adjustment" phase is executed until the engine torque Te decreases to a predetermined low torque Telow that allows the K0 clutch 20 to be determined to be switched to the released state. The predetermined low torque Telow is, for example, a no-load operating state in which the K0 clutch 20 is released and the engine 12 is self-sustaining with no load (for example, a state of idling rotation at the minimum rotational speed that is the limit of stability, or a no-load is the engine torque Te output to the engine connection shaft 34, that is, the idle torque Teidl [Nm], which is substantially zero [Nm]. That is, the predetermined low torque Telow is an engine torque Te that is considered to be output from the engine 12 in a no-load state that operates according to a predetermined engine torque command value Ste1, which will be described later. The engine torque Te used for comparison with the predetermined low torque Telow may be the actual engine torque Ter or a value obtained by multiplying the actual engine torque Ter by a safety factor SF.

In the "pre-K0 release pressure adjustment" phase, when the engine torque Te decreases to a predetermined low torque Telow, a transition is made to the "K0 release transition SW" phase (see time t4-t5). In the "K0 release transition SW" phase, in order to release the K0 clutch 20, the SK0 oil pressure PRsk0 is swept down (=gradually decreased) from the engagement maintaining oil pressure PRk0c to the pack end pressure of the K0 clutch 20 at the first gradient SW1. This is the phase for outputting the SK0 oil pressure command value Ssk0. The "K0 release transition SW" phase is executed until the SK0 oil pressure PRsk0 decreases to the pack end pressure at which the K0 torque Tk0 becomes zero [Nm].

In the "K0 release transition SW" phase, when the SK0 oil pressure PRsk0 drops to the pack end pressure, a transition is made to the "K0 complete release transition SW" phase (see time t5-t6). The "K0 full release transition SW" phase is a phase for outputting the SK0 oil pressure command value Ssk0 for sweeping down the SK0 oil pressure PRsk0 from the pack end pressure to the release ensuring oil pressure PRk0rl at the first gradient SW1. The disengagement protection oil pressure PRk0rl is, for example, a predetermined value of the SK0 oil pressure PRsk0 that can ensure that the K0 clutch 20 is in the disengagement state. The "K0 full release transition SW" phase is executed until the SK0 oil pressure PRsk0 drops to the release protection oil pressure PRk0rl.

In the "K0 full release transition SW" phase, when the SK0 oil pressure PRsk0 drops to the release protection oil pressure PRk0rl, the phase is changed to the "K0 post-release SW" phase (see time t6-t7). In the "SW after K0 release SW" phase, the SK0 oil pressure command value Ssk0 that sweeps down the SK0 oil pressure PRsk0 from the release protection oil pressure PRk0rl to the EV steady-state K0 oil pressure PRk0ev (=0 [kPa]) at the second gradient SW2 is output. is. The absolute value of the second slope SW2 is larger than the absolute value of the first slope SW1. The "SW after K0 release" phase is executed until the SK0 oil pressure PRsk0 decreases to the EV steady-state K0 oil pressure PRk0ev.

In the "SW after K0 release" phase, when the SK0 oil pressure PRsk0 drops to the EV steady-state K0 oil pressure PRk0ev (=0), the phase is shifted to the "K0 complete release" phase (see time t7-t9). The "K0 full release" phase is a phase in which the SK0 oil pressure command value Ssk0 is output so that the SK0 oil pressure PRsk0 is the EV steady-state K0 oil pressure PRk0ev until the engine stop control is completed.

In the "K0 complete release" phase, for example, the engine 12 is put on standby in a self-sustaining state as needed (see time t7-t8). After that, the fuel of the engine 12 is cut and the engine 12 is stopped (see time t8-t9). When the engine rotation speed Ne is determined to be zero [rpm], the engine stop control is completed (see time t9).

In the "stop K0 standby" phase and the "pre-K0 pressure regulation standby" phase, the K0 clutch 20 is in a fully engaged state. In the "pre-K0 release pressure adjustment" phase, the K0 clutch 20 is in a preparatory state before being released. In the "K0 disengagement transition SW" phase, the K0 clutch 20 is in transition to the disengaged state. In the "K0 full release transition SW" phase, the K0 clutch 20 is in a transition state to a full release state. In the "SW after K0 release" phase and the "K0 complete release" phase, the K0 clutch 20 is in a completely released state.

In addition, since the torques Te, Tm, etc. of the engine 12 and the electric motor MG are controlled when the engine 12 is stopped, there are a plurality of progression stages divided for each torque control of the engine 12 and the electric motor MG that are switched during the process of stopping the engine 12. That is, phases are defined.

FIG. 4 is a time chart illustrating an example of each phase of torque control of the engine 12 and the electric motor MG in the process of stopping the engine 12, which is performed in parallel with the K0 control of FIG. In FIG. 4 , “torque control phase” indicates a transition state of each phase of torque control of the engine 12 and the electric motor MG during the process of stopping the engine 12 . These phases are defined as "engine torque down", "power switching", "engine independence", "engine stop", and the like.

After starting the engine stop control, the "engine torque down" phase (see time t1-t4A) is executed. In the "engine torque down" phase, after the start of the engine stop control, the engine torque Te is reduced to an engine torque Te that can be released by the K0 clutch 20, such as an idle torque Teidl (predetermined low torque Telow), while ensuring the required driving torque Trdem requested by the driver. This is the phase in which the For example, in the "engine torque down" phase, the engine torque Te is reduced to the idle torque Teidl, and the engine torque Te is reduced to the idle torque Teidl to secure the required drive torque Trdem. This is the phase in which the torque to be applied is output from the electric motor MG. As shown in FIG. 4, in the "engine torque down" phase, after the start of the engine stop control, the engine torque command value (dynamic engine torque) Ste [Nm] indicated by the thick solid line is set to a predetermined engine torque. The MG torque command value (dynamic MG torque) Stm [Nm] indicated by the thin solid line is decreased (gradually decreased) to the command value Ste1 [Nm], and the decrease in the engine torque command value Ste [Nm] is compensated for. be raised. Note that the "engine torque down" phase continues until the time when the K0 clutch 20 starts to be released (time t4A), that is, the K0 torque command value (dynamic K0 torque) Stk0 [Nm] indicated by the long dashed line. becomes equal to or less than the engine torque command value Ste [Nm]. The engine torque command value Ste is a torque command value for controlling the engine torque Te, the MG torque command value Stm is a torque command value for controlling the MG torque Tm, and the K0 torque command value Stk0 is , are torque command values for controlling the K0 torque Tk0, which is the torque capacity of the K0 clutch 20. FIG. The predetermined engine torque command value Ste1 is a torque command value for controlling the engine torque Te to the idle torque Teidl. In FIG. 4, the required driving torque command value (dynamic required driving torque) Stemg [Nm] indicated by a short dashed line is constant during the process of stopping the engine 12 .

In the "engine torque down" phase, when the K0 torque command value Stk0 becomes equal to or less than the engine torque command value Ste (predetermined engine torque command value Ste1), a transition is made to the "power switching" phase (see time t4A-t6). In the "power switching" phase, the K0 torque Tk0, which is the torque capacity of the K0 clutch 20, is reduced, and the driving force source transmitted to the driving wheels 14 by disengaging the K0 clutch 20 is changed from the engine 12 and the electric motor MG to the electric motor. This is the phase to switch to MG only. For example, the "power switching" phase is a phase in which the engine torque Te is maintained at the idle torque Teidl and the torque (K0 torque Tk0) reduced to release the K0 clutch 20 is output from the electric motor MG. As shown in FIG. 4, in the "power switching" phase, the engine torque command value Ste is maintained at the predetermined engine torque command value Ste1, and the MG torque command value Stm increases to compensate for the decrease in the K0 torque command value Stk0. Let me. In the "power switching" phase, the MG torque command value Stm is increased until it matches the required drive torque command value Stetm (Stm=Stetm). The "power switching" phase is executed until the K0 torque command value Stk0 becomes zero [Nm] and the K0 clutch 20 is completely released, that is, until the time t6.

In the "power switching" phase, when the K0 clutch 20 is completely released, a transition is made to the "engine independence" phase (see time t6-t8). The "engine self-sustaining" phase is a phase in which the engine 12 is operated in a self-sustaining state for a predetermined period of time TE (t8-t6) [sec] after the K0 clutch 20 is released. The self-sustaining operation is a state in which the engine 12 is disconnected from the driving force source so that the driving force of the engine 12 is not transmitted to the driving wheels 14 (a state in which the engine 12 is idling). It is to drive while continuously outputting the aforementioned idle torque Teidl (≈0 Nm). For example, the "engine independence" phase is a phase in which the engine torque Te is maintained at the idle torque Teidl and the MG torque Tm is controlled so that the required drive torque Trdem is covered by the output of the electric motor MG alone. As shown in FIG. 4, in the "engine self-sustaining" phase, the engine torque command value Ste is maintained at the predetermined engine torque command value Ste1, and the MG torque command value Stm is matched with the required drive torque command value Stetm. The "engine independence" phase is executed until the engine rotation speed Ne becomes equal to or lower than a predetermined rotation speed Ne1 [rpm] (time t8). The predetermined rotation speed Ne1 is, for example, a judgment value for determining whether or not the engine rotation speed Ne is stable. It is the minimum rotation speed at which rotation is possible, that is, the idle rotation speed (lowest no-load rotation speed), and the rotation speed at which the K0 clutch 20 is released and the fuel cut (FC) is performed without adversely affecting the catalyst function. is. That is, the predetermined period TE is the period from when the K0 clutch 20 is completely released until the engine rotation speed Ne becomes equal to or less than the predetermined rotation speed Ne1, that is, after the K0 clutch 20 is completely released, the engine rotation speed Ne stabilizes. It is a period until

In the "engine independent" phase, when the engine rotation speed Ne becomes equal to or lower than a predetermined rotation speed Ne1, the phase is shifted to the "engine stop" phase (see time t8-t9). The “engine stop” phase is a phase in which a fuel cut (FC) is performed to stop the engine 12 . For example, the "engine stop" phase is a phase in which a fuel cut (FC) is performed to stop the engine 12, and the MG torque Tm is controlled so that the required driving torque Trdem is covered by the output of the electric motor MG alone. As shown in FIG. 4, in the "engine stop" phase, the fuel is cut and the MG torque command value Stm is matched with the required driving torque command value Stetm. The "engine stop" phase is executed until the engine rotation speed Ne becomes zero [rpm] (time t9).

Returning to FIG. 1, when the hybrid control unit 92 determines that there is an engine stop request, the clutch control unit 94 maintains the SCK0 command signal Ssck0 as a non-energization (OFF) signal and reduces the SK0 oil pressure PRsk0. An SK0 oil pressure command value Ssk0 is output to the oil pressure control circuit 56 as the EV steady-state K0 oil pressure PRk0ev (=0).

When the hybrid control unit 92 determines that there is an engine stop request, the clutch control unit 94 determines whether the actual engine torque Ter becomes equal to or less than a predetermined engine torque Tef during a transition period in which the actual engine torque Ter is gradually decreased. determine whether or not

When the clutch control unit 94 determines that the actual engine torque Ter has become equal to or less than the predetermined engine torque Tef, the SCK0 command signal Ssck0 remains the non-energization (OFF) signal, and the SK0 oil pressure PRsk0 is set to the EV steady-state K0 oil pressure. From PRk0ev (=0), the SK0 oil pressure command value Ssk0 is output to the oil pressure control circuit 56 as the engagement maintaining oil pressure PRk0c.

The clutch control unit 94 supplies the SK0 oil pressure PRsk0 based on whether or not a predetermined filling time TMfil has elapsed since the time when the SK0 oil pressure PRsk0 was switched from the EV steady-state K0 oil pressure PRk0ev to the engagement maintaining oil pressure PRk0c (time t2). It is determined whether or not the hydraulic oil OIL is filled in the pressure regulation oil passage 116 to be controlled.

When the clutch control unit 94 determines that the pressure adjustment oil passage 116 is filled with the hydraulic oil OIL, the SCK0 command signal Ssck0 is turned off (OFF) while keeping the SK0 oil pressure PRsk0 at the engagement maintaining oil pressure PRk0c. to an energization (ON) signal (switching the K0 oil pressure PRk0 from the line pressure PL to the SK0 oil pressure PRsk0).

The clutch control unit 94 determines whether or not the actual engine torque Ter has decreased to a predetermined low torque Telow during the transition in which the actual engine torque Ter is gradually decreased.

When the clutch control unit 94 determines that the actual engine torque Ter has decreased to the predetermined low torque Telow, the SK0 oil pressure PRsk0, that is, the K0 oil pressure PRk0, changes from the engagement maintaining oil pressure PRk0c to the pack end pressure of the K0 clutch 20 at the first gradient. SK0 oil pressure command value Ssk0 to be swept down by SW1 is output to the oil pressure control circuit 56 .

When the SK0 oil pressure PRsk0 sweeps down from the engagement maintaining oil pressure PRk0c, the clutch control unit 94 determines whether the SK0 oil pressure PRsk0 has become the pack end pressure of the K0 clutch 20 or less.

When the clutch control unit 94 determines that the SK0 oil pressure PRsk0 has become equal to or lower than the pack end pressure of the K0 clutch 20, the SK0 oil pressure PRsk0 is swept down from the pack end pressure to the release securing oil pressure PRk0rl at the first gradient SW1. The SK0 oil pressure command value Ssk0 is output to the oil pressure control circuit 56 .

When the SK0 oil pressure PRsk0 sweeps down from the pack end pressure, the clutch control unit 94 determines whether or not the SK0 oil pressure PRsk0 has become equal to or lower than the release protection oil pressure PRk0rl.

When the clutch control unit 94 determines that the SK0 oil pressure PRsk0 has become equal to or lower than the release guarantee oil pressure PRk0rl, the SK0 oil pressure PRsk0 is set at the second gradient from the release guarantee oil pressure PRk0rl to the EV steady-state K0 oil pressure PRk0ev (=0 [kPa]). SK0 oil pressure command value Ssk0 to be swept down by SW2 is output to the oil pressure control circuit 56 .

When the SK0 oil pressure PRsk0 sweeps down from the release protection oil pressure PRk0rl, the clutch control unit 94 determines whether or not the SK0 oil pressure PRsk0 has reached the EV steady-state K0 oil pressure PRk0ev (=0 [kPa]).

When the clutch control unit 94 determines that the SK0 oil pressure PRsk0 has become the EV steady state K0 oil pressure PRk0ev (=0 [kPa]), the clutch control unit 94 sets the SK0 oil pressure PRsk0 to the EV steady state K0 oil pressure PRk0ev (=0 [kPa]). The SK0 oil pressure command value Ssk0 to be maintained is output to the oil pressure control circuit 56 .

When the hybrid control unit 92 determines that there is an engine stop request, the engine control unit 92 outputs an engine control command signal Se for decreasing (gradually decreasing) the engine torque Te to the idle torque Teidl in order to bring the engine 12 into an idling state. 50, and outputs to the inverter 52 an MG control command signal Sm that causes the electric motor MG to output a torque that decreases when the engine torque Te is reduced to the idle torque Teidl in order to secure the required drive torque Trdem.

When the hybrid control unit 92 determines that there is an engine stop request, the hybrid control unit 92 determines whether or not the K0 clutch 20 has started to be released. For example, when the SK0 oil pressure command value Ssk0 [Nm] becomes equal to or less than the engine torque command value Ste [Nm], that is, when the K0 torque Tk0 [Nm] becomes equal to or less than the engine torque Te [Nm], the hybrid control unit 92 controls the K0 clutch 20 has started to release.

When the hybrid control unit 92 determines that the K0 clutch 20 has started to disengage, the hybrid control unit 92 outputs an engine control command signal Se for maintaining the engine torque Te at the idle torque Teidl to the engine control device 50, and outputs the K0 torque. An MG control command signal Sm is output to the inverter 52 to increase the MG torque Tm so as to compensate for the decrease in Tk0.

When the hybrid control unit 92 determines that the K0 clutch 20 has started to be released, it determines whether the K0 clutch 20 has been released, that is, completely released. For example, the hybrid control unit 92 determines that the K0 clutch 20 is completely released when the K0 torque Tk0 becomes zero, that is, when the SK0 oil pressure PRsk0 becomes equal to or lower than the disengagement protection oil pressure PRk0rl.

When the hybrid control unit 92 determines that the K0 clutch 20 is completely released, the hybrid control unit 92 reduces the engine torque Te to the idle torque Teidl for the predetermined period TE in order to operate the engine 12 in the self-sustaining state for the predetermined period TE. is output to the engine control device 50, and an MG control command signal Sm is output to the inverter 52 so that the MG torque Tm becomes the required drive torque Trdem.

When the hybrid control unit 92 determines that the K0 clutch 20 has been completely released, the hybrid control unit 92 determines whether or not a predetermined period TE has passed since the K0 clutch 20 was completely released. For example, after the K0 clutch 20 is completely released, the hybrid control unit 92 determines that the predetermined period TE has passed when the engine rotation speed Ne becomes equal to or lower than the predetermined rotation speed Ne1.

When the hybrid control unit 92 determines that the predetermined period TE has elapsed, the hybrid control unit 92 outputs an engine control command signal Se for cutting fuel (FC) to the engine control device 50, and the MG torque Tm exceeds the required drive torque Trdem. The MG control command signal Sm is output to the inverter 52 as follows. Note that the hybrid control unit 92 performs engine control to prohibit fuel cut (FC) from the time point when it is determined that there is an engine stop request (time point t1) to the time point when it is determined that the predetermined period TE has passed (time point t8). A command signal Se is output to the engine control device 50 .

FIG. 5 is a flowchart for explaining the essential part of the control operation of the electronic control unit 90, and is a flowchart for explaining the control operation for suppressing the shock when switching the engine 12 from the operating state to the stopped state. Executed repeatedly. 3 and 4 are diagrams showing examples of time charts when the control operation shown in the flowchart of FIG. 5 is executed.

In FIG. 5, first, in step S10 (hereinafter, step omitted) corresponding to the function of the hybrid control unit 92, it is determined whether or not there is an engine stop request. If the determination in S10 is negative, this routine is terminated. If the determination in S10 is affirmative (time t1 in FIGS. 3 and 4), in S20 corresponding to the function of the hybrid control unit 92, the engine torque Te is reduced while the required drive torque Trdem is secured by the MG torque Tm. . Also, fuel cut (FC) is prohibited. Next, in S30 corresponding to the function of the clutch control unit 94, the SK0 oil pressure PRsk0 is set to the EV steady-state K0 oil pressure PRk0ev (=0) while the SCK0 command signal Ssck0 remains a non-energization (OFF) signal. Next, in S40 corresponding to the function of the clutch control section 94, it is determined whether or not the actual engine torque Ter has become equal to or less than the predetermined engine torque Tef. If the determination in S40 is negative, S40 is repeatedly executed. If the determination in S40 is affirmative (time t2 in FIGS. 3 and 4), in S50 corresponding to the function of the clutch control unit 94, the SK0 oil pressure PRsk0 is changed from the EV steady-state K0 oil pressure PRk0ev (=0) to the engagement maintenance oil pressure PRk0c. It is said that

Next, in S60 corresponding to the function of the clutch control section 94, it is determined whether or not the hydraulic oil OIL is filled in the pressure regulating oil passage 116 to which the SK0 oil pressure PRsk0 is supplied. If the determination in S60 is negative, S60 is repeatedly executed. If the determination in S60 is affirmative (time t3 in FIGS. 3 and 4), the SCK0 command signal Ssck0 is switched from a de-energization (OFF) signal to an energization (ON) signal in S70 corresponding to the function of the clutch control unit 94. Thus, the K0 oil pressure PRk0 is switched from the line pressure PL to the SK0 oil pressure PRsk0. Next, in S80 corresponding to the function of the clutch control section 94, it is determined whether or not the actual engine torque Ter has decreased to a predetermined low torque Telow. If the determination in S80 is negative, S80 is repeatedly executed. If the determination in S80 is affirmative (time t4 in FIGS. 3 and 4), in S90 corresponding to the function of the clutch control unit 94, the SK0 oil pressure PRsk0 is changed from the engagement maintaining oil pressure PRk0c to the pack end pressure at the first gradient SW1. Swept down. Next, in S100 corresponding to the function of the hybrid control unit 92, it is determined whether or not the release of the K0 clutch 20 has started. If the determination in S100 is negative, S100 is repeatedly executed. If the determination in S100 is affirmative (time t4A in FIG. 4), in S110 corresponding to the function of the hybrid control unit 92, the engine torque Te is maintained at the idle torque Teidl and the decrease in the K0 torque Tk0 is compensated for. MG torque Tm is increased.

Next, in S120 corresponding to the function of the clutch control section 94, it is determined whether or not the SK0 oil pressure PRsk0 has become equal to or lower than the pack end pressure of the K0 clutch 20 or not. If the determination in S120 is negative, S120 is repeatedly executed. If the determination in S120 is affirmative (at time t5 in FIGS. 3 and 4), in S130 corresponding to the function of the clutch control unit 94, the SK0 oil pressure PRsk0 changes from the pack end pressure to the release securing oil pressure PRk0rl at the first gradient SW1. Swept down. Next, at S140 corresponding to the function of the hybrid control unit 92, it is determined whether or not the K0 clutch 20 has been completely released, that is, whether or not the SK0 oil pressure PRsk0 has become equal to or lower than the release securing oil pressure PRk0rl. If the determination in S140 is negative, S140 is repeatedly executed. If the determination in S140 is affirmative (time t6 in FIGS. 3 and 4), in S150 corresponding to the function of the hybrid control unit 92, the engine 12 is operated in the self-sustained state.

Next, in S160 corresponding to the function of the clutch control unit 94, the SK0 oil pressure PRsk0 is swept down from the release guarantee oil pressure PRk0rl to the EV steady-state K0 oil pressure PRk0ev (=0 [kPa]) at the second gradient SW2. Next, in S170 corresponding to the function of the clutch control unit 94, it is determined whether or not the SK0 oil pressure PRsk0 has become the EV steady-state K0 oil pressure PRk0ev (=0 [kPa]). If the determination in S170 is negative, S170 is repeatedly executed. If the determination in S170 is affirmative (time t7 in FIGS. 3 and 4), in S180 corresponding to the function of the hybrid control unit 92, it is determined whether or not the engine 12 has been independently operated for the predetermined period TE, that is, the engine rotation It is determined whether or not the speed Ne has become equal to or less than a predetermined rotational speed Ne1. If the determination in S180 is negative, S180 is repeatedly executed. If the determination in S180 is affirmative (time t8 in FIGS. 3 and 4), fuel cut (FC) is performed to stop the engine 12 in S190 corresponding to the function of the hybrid control unit 92 .

As described above, according to the electronic control unit 90 of the vehicle 10 of the present embodiment, when the engine stop request for switching the engine 12 from the operating state to the stopped state is determined, the engine torque Te is reduced to the idle torque Teidl. After the K0 clutch 20 is released, the engine 12 is operated in a self-sustaining state for a predetermined period TE, and then the fuel supply to the engine 12 is stopped. Therefore, after the K0 clutch 20 is released, the engine 12 is operated in a self-sustaining state for a predetermined period TE, so that the engine rotation speed Ne is stabilized, it is possible to suppress the shock when the engine 12 stops.

Further, according to the electronic control unit 90 of the vehicle 10 of the present embodiment, the predetermined period TE is the period from after the K0 clutch 20 is released until the engine rotation speed Ne becomes equal to or lower than the predetermined rotation speed Ne1. is. Therefore, it can be suitably determined that the engine rotation speed Ne has stabilized after the K0 clutch 20 is released.

Further, according to the electronic control unit 90 of the vehicle 10 of the present embodiment, the presence or absence of the engine stop request is determined at least during the hybrid running in which the driving force from the engine 12 is used for running, and the engine stop request is determined. If so, the electric motor MG outputs a torque that decreases when the engine torque Te is set to the idle torque Teidl. Therefore, the fluctuation (step) in the torque transmitted to the drive wheels 14 when the engine 12 is stopped can be suitably reduced.

Further, according to the electronic control device 90 of the vehicle 10 of this embodiment, the vehicle 10 is provided with the hydraulic control circuit 56 for controlling the K0 hydraulic pressure PRk0, which is the hydraulic pressure for switching the control state of the K0 clutch 20, and the engine When the stop request is determined, the K0 oil pressure PRk0 is the engagement maintaining oil pressure that generates the torque capacity of the K0 clutch 20 according to the engine torque Te of the engine 12 while the K0 clutch 20 is maintained in the engaged state. When the engine torque Te of the engine 12 drops to the idling torque Teidl, the hydraulic control circuit 56 lowers the K0 oil pressure PRk0 from the engagement maintaining oil pressure PRk0c, thereby opening the K0 clutch 20. release the Therefore, the fluctuation (step) in the torque transmitted to the drive wheels 14 when the K0 clutch 20 is disengaged can be suitably reduced.

Although the embodiments of the present invention have been described in detail above with reference to the drawings, the present invention is also applicable to other aspects.

For example, in the above-described embodiment, the "engine self-sustaining" phase was executed after the K0 clutch 20 was released until the engine rotation speed Ne became equal to or lower than the predetermined rotation speed Ne1. , the K0 clutch 20 may be released until a predetermined period of time [sec] elapses. The predetermined period is a period from when the K0 clutch 20 is released to when the engine speed Ne stabilizes, which is set in advance by experiment or the like. Further, the "engine self-sustaining" phase may be executed, for example, until the engine rotation speed Ne becomes equal to or lower than the predetermined rotation speed Ne1 for a predetermined period after the K0 clutch 20 is released.

Further, in the above-described embodiment, the automatic transmission 24 is a planetary gear type automatic transmission, but it is not limited to this aspect. The automatic transmission 24 may be a synchronous mesh parallel twin-shaft automatic transmission including a known DCT (Dual Clutch Transmission), a known belt-type continuously variable transmission, or the like. Alternatively, the automatic transmission 24 does not necessarily have to be provided.

Further, in the above-described embodiment, the torque converter 22 is used as the hydrodynamic transmission device, but the present invention is not limited to this aspect. For example, instead of the torque converter 22, another hydrodynamic transmission such as a fluid coupling that does not amplify torque may be used as the hydrodynamic transmission. Alternatively, the hydrodynamic transmission device does not necessarily have to be provided, and may be replaced with, for example, a starting clutch.

It should be noted that what has been described above is just one embodiment, and the present invention can be implemented in aspects with various modifications and improvements based on the knowledge of those skilled in the art.

10: Vehicle 12: Engine 14: Driving Wheel 20: K0 Clutch (Clutch)
56: Hydraulic control circuit 90: Electronic control device (control device)
92: Hybrid control unit 94: Clutch control unit MG: Electric motor Ne: Engine rotation speed (rotational speed)
Ne1: Predetermined rotation speed PRk0: K0 hydraulic pressure (clutch hydraulic pressure)
PRk0c: Engagement maintenance oil pressure TE: Predetermined period Te: Engine torque (output torque)
Teidl: idle torque

Claims (4)

A control device for a vehicle comprising an engine, an electric motor connected to a power transmission path between the engine and drive wheels so as to be able to transmit power, and a clutch provided between the engine and the electric motor There is
When an engine stop request for switching the engine from an operating state to a stopped state is determined, after the output torque of the engine is set to a predetermined idle torque and the clutch is released, the engine is operated in a self-supporting state. A control device for a vehicle, characterized by performing a fuel cut to stop the supply of fuel to the engine after the vehicle has been operated for a predetermined period. 2. The control device for a vehicle according to claim 1, wherein the predetermined period is a period from after the clutch is released until the rotational speed of the engine becomes equal to or lower than a predetermined rotational speed. The presence or absence of the engine stop request is determined at least during hybrid running in which driving force from the engine is used,
3. The control device for a vehicle according to claim 1, wherein when the engine stop request is determined, the electric motor outputs a torque that decreases when the output torque of the engine is set to the idle torque. The vehicle is provided with a hydraulic control circuit for controlling clutch hydraulic pressure, which is hydraulic pressure for switching the control state of the clutch,
When the engine stop request is determined, the clutch hydraulic pressure is an engagement maintenance hydraulic pressure that generates a torque capacity of the clutch corresponding to the output torque of the engine while the clutch is maintained in the engaged state. The hydraulic control circuit is controlled so that
4. The clutch is released by lowering the clutch hydraulic pressure from the engagement maintaining hydraulic pressure by the hydraulic control circuit when the output torque of the engine decreases to the idle torque. vehicle controller.

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