Hybrid vehicle control device

Abstract

To provide a control device, for a hybrid vehicle using an engine and an electric motor as drive power sources, capable of promptly completing downshifting when a driver switches to manual shift transmission while a transmission interposed between a drive power source and drive wheels performs the downshifting.SOLUTION: When detecting switchover to a second transmission mode M2 while an automatic transmission 24 is performing downshifting associated with regeneration through an electric motor MG, a hybrid vehicle control device makes a variation per unit time of hydraulic pressure PRcb1 of an engaging side engagement device CB1 larger than that when a transmission mode is not switched to the second transmission mode M2 and thereby enabling the downshifting when the transmission mode is switched to the second transmission mode M2 to be completed faster than the downshifting when the transmission mode is not switched thereto with progression of an inertia phase accelerated.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a gear change control for a hybrid vehicle that uses an engine and an electric motor as driving power sources. [Background technology]

[0002] Patent document 1 describes a method for suppressing shock to the vehicle that occurs when downshifting during regenerative coasting in a hybrid vehicle equipped with an engine, an electric motor, and a transmission provided in the power transmission path between the engine and the electric motor and the drive wheels, by selecting a gear to which the shift is to be made that causes less shock than the gear set in a normal downshift. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-159181 Summary of the Invention [Problem to be solved by the invention]

[0004] In addition to a method of determining a gear based on a preset shift line of an automatic transmission, a downshift can also be requested by the driver manually selecting a gear by, for example, operating a shift lever. When the driver manually selects a gear during a downshift involving regeneration, the downshift must be completed quickly to achieve the deceleration desired by the driver. However, in conventional systems, the same shift control is executed regardless of whether the driver operates the shift lever during the downshift, which means it takes time to complete the shift and achieve the deceleration desired by the driver.

[0005] The present invention has been made against the background of the above circumstances, and its purpose is to provide a control device that can quickly complete a downshift in a hybrid vehicle that is equipped with a transmission in the power transmission path between the engine and electric motor that serve as the driving force source and the drive wheels when the driver switches to manual shifting during a downshift. [Means for solving the problem]

[0006] The gist of the first invention is a control device for a hybrid vehicle, (a) which is applied to a hybrid vehicle having an engine, an electric motor, and a transmission provided in a power transmission path between the engine and the electric motor and drive wheels, and which is configured to be switchable between a first shift mode in which a gear is automatically established based on the driving state, and a second shift mode in which a gear is established by manual operation by the driver, and which is configured to increase the command pressure of an engagement side engagement device that is engaged during a shift transition period, and which is characterized in that (b) when a downshift based on the first shift mode is performed during regenerative driving in which the vehicle is traveling with regeneration by the electric motor, and when the driver switches to the second shift mode before the start of the inertia phase, the change amount per unit time of the command pressure of the engagement side engagement device during the inertia phase is increased compared to when the mode cannot be switched to the second shift mode. [Effects of the Invention]

[0007] According to the first aspect of the present invention, when switching to the second shift mode is detected during a downshift of the transmission involving regeneration by the electric motor, the amount of change per unit time in the command pressure of the on-coming engagement device is increased compared to when switching to the second shift mode is not possible, so the inertia phase progresses more quickly and the downshift can be completed earlier than when switching to the second shift mode is not possible. As a result, the downshift time is shortened and the deceleration requested by the driver can be achieved earlier. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating a schematic configuration of a vehicle to which the present invention is applied, and is also a diagram illustrating main parts of control functions and control systems for various controls in the vehicle. [Figure 2] 3 is an engagement operation table showing combinations of engagement devices for establishing gear stages of an automatic transmission. [Figure 3] 10 is a time chart illustrating a control state when a switching operation from the D position to the S position is performed during a downshift involving regeneration. [Figure 4] This is a flowchart explaining the main parts of the control operation of the electronic control device, and is a flowchart explaining the control operation that allows the gear change to be completed quickly when a switching operation to the S position is performed during a downshift involving regeneration. DETAILED DESCRIPTION OF THE INVENTION

[0009] 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. [Example]

[0010] Fig. 1 is a diagram illustrating the schematic configuration of a vehicle 10 to which the present invention is applied, as well as a diagram illustrating the main parts of the control functions and control systems for various controls in the vehicle 10. In Fig. 1, the vehicle 10 is a hybrid vehicle equipped with an engine 12 and an electric motor MG, which are driving power sources for traveling. The vehicle 10 also has drive wheels 14 and a power transmission device 16 provided in a power transmission path between the engine 12 and the drive wheels 14.

[0011] The engine 12 is a known internal combustion engine such as a gasoline engine, a diesel engine, etc. An electronic control device 90 (described later) controls an engine control device 50 including a throttle actuator, a fuel injection device, an ignition device, etc., provided in the vehicle 10, thereby controlling the engine torque Te, which is the output torque of the engine 12.

[0012] The electric motor MG is a rotating electric machine, a so-called motor generator, that functions as both a motor that generates mechanical power from electric power and a generator that generates electric power from mechanical power. The electric motor MG is connected to a battery 54 provided in the vehicle 10 via an inverter 52 provided in the vehicle 10. The inverter 52 is controlled by an electronic control device 90 (described later), which controls the MG torque Tm, which is the output torque of the electric motor MG. For example, when the rotation direction of the electric motor MG is forward, which is the same as the rotation direction of the engine 12 during operation, the MG torque Tm is a powering torque when it is a positive torque on the acceleration side, and a regenerative torque when it is a negative torque on the deceleration side. Specifically, the electric motor MG generates power for traveling using electric power supplied from the battery 54 via the inverter 52 instead of or in addition to the engine 12. The electric motor MG also generates electric power using the power of the engine 12 and the driven force input from the drive wheels 14. The electric power generated by the electric motor MG is stored in the battery 54 via the inverter 52. The battery 54 is an electricity storage device that supplies and receives electric power to the electric motor MG. The electric power also refers to electrical energy unless otherwise specified. The power also refers to torque or force unless otherwise specified.

[0013] The power transmission device 16 includes a K0 clutch 20, 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 K0 clutch 20 is a clutch provided between the engine 12 and the electric motor MG in the power transmission path between the engine 12 and the drive wheels 14. The torque converter 22 is connected to the engine 12 via the K0 clutch 20.

[0014] The automatic transmission 24 is provided in a power transmission path between the engine 12 and electric motor MG and the drive wheels 14. In other words, the automatic transmission 24 constitutes a part of the power transmission path between the engine 12 and electric motor MG and the drive wheels 14. 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, etc. The power transmission device 16 also includes an engine connecting shaft 34 that connects the engine 12 and K0 clutch 20, an electric motor connecting shaft 36 that connects the K0 clutch 20 and the torque converter 22, etc.

[0015] 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. The electric motor MG is connected to a power transmission path between the engine 12 and the drive wheels 14, particularly to a power transmission path between the K0 clutch 20 and the torque converter 22. In other words, the electric motor MG is connected to the torque converter 22 and the automatic transmission 24 so as to be able to transmit power without passing through the K0 clutch 20. In other words, the torque converter 22 and the automatic transmission 24 each constitute part of the power transmission path between the electric motor MG and the drive wheels 14. The torque converter 22 and the automatic transmission 24 transmit the driving power from the driving power sources of the engine 12 and the electric motor MG to the drive wheels 14, respectively.

[0016] The torque converter 22 includes a pump wheel 22a connected to an electric motor connecting shaft 36 and a turbine wheel 22b connected to a transmission input shaft 38, which is an input rotating member of the automatic transmission 24. The pump wheel 22a is connected to the engine 12 via the K0 clutch 20 and is also directly connected to the electric motor MG. The pump wheel 22a is the input member of the torque converter 22, and the turbine wheel 22b is the output member of the torque converter 22. The electric motor connecting shaft 36 is also the input rotating member of the torque converter 22. The transmission input shaft 38 is also the output rotating member of the torque converter 22, formed integrally with a turbine shaft that is rotationally driven by the turbine wheel 22b. The torque converter 22 is a fluid transmission that transmits driving force from each of the driving force sources (engine 12, electric motor MG) to the transmission input shaft 38 via fluid. The torque converter 22 includes a known lock-up clutch 40 (hereinafter referred to as LU clutch 40) that connects and disconnects the pump wheel 22a and the turbine wheel 22b.

[0017] The operating state, i.e., the control state, of the LU clutch 40 is switched by changing the LU clutch torque Tlu, which is the torque capacity of the LU clutch 40, using the regulated LU oil pressure PRlu supplied from a hydraulic control circuit 56 provided in the vehicle 10. The control states of the LU clutch 40 include a fully released state in which the LU clutch 40 is released, a slip state in which the LU clutch 40 is engaged with slippage, and a fully engaged state in which the LU clutch 40 is engaged.

[0018] The automatic transmission 24 is a known planetary gear automatic transmission equipped with, for example, one or more planetary gear sets (not shown) and a plurality of engagement devices CB. The engagement devices CB are hydraulic friction engagement devices, such as multi-plate or single-plate clutches or brakes pressed by hydraulic actuators, or band brakes tightened by hydraulic actuators. Each engagement device CB has its torque capacity, or CB torque Tcb, changed by regulated hydraulic pressure PRcb supplied from a hydraulic control circuit 56, thereby switching its control state, such as an engaged state or a disengaged state. In this embodiment, the engagement devices CB are composed of, for example, four clutches C1 to C4 and two brakes B1 and B2.

[0019] The automatic transmission 24 is a stepped automatic transmission in which one of a plurality of gear stages (also referred to as "gear stages") with different speed ratios (also referred to as "gear ratios") γat (=AT input rotation speed Ni / AT output rotation speed No) is established by engaging one of the engagement devices CB. That is, the automatic transmission 24 shifts to a plurality of gear stages according to combinations of engagement and disengagement of the plurality of engagement devices CB (clutches C1 to C4 and brakes B1, B2). Specifically, the automatic transmission 24 shifts gears based on an engagement operation table shown in FIG. 2 that shows combinations of the engagement devices CB for establishing the gear stages of the automatic transmission 24. In FIG. 2, "◯" indicates an engagement of an engagement device CB, and "X" indicates a disengagement of an engagement device CB. As shown in FIG. 2, the automatic transmission 24 is configured to be able to switch between 10 gear stages from 1st gear stage 1st to 10th gear stage 10th by changing the combination of engagement and disengagement of each engagement device CB.

[0020] The automatic transmission 24 determines the gear position by an electronic control device 90 (described later) based on the accelerator opening θacc, which is the amount of operation of the accelerator pedal 42 by the driver, and the vehicle speed V. Note that the decision to shift gears may be made not only based on the accelerator opening θacc, but also based on a related value of the accelerator opening θacc that is correlated with the accelerator opening θacc, such as the throttle opening θth. Similarly, the decision to shift gears may be made not only based on the vehicle speed V, but also based on a related value of the vehicle speed V that is correlated with the vehicle speed V, such as the AT output rotation speed No. 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 also the rotation speed of the output rotating member of the torque converter 22 and is equivalent to the turbine rotation speed Nt, which is the output rotation speed of the torque converter 22. The AT input rotation speed Ni can be expressed in terms of 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. The automatic transmission 24 is configured so that the gear position can be changed by the driver manually operating the shift lever 48. The automatic transmission 24 corresponds to the transmission of the present invention.

[0021] The K0 clutch 20 is a wet or dry friction engagement device configured with a multi-plate or single-plate clutch pressed by a hydraulic actuator (not shown). The control state of the K0 clutch 20, such as an engaged state or a disengaged state, is switched by an electronic control device 90 (described later) controlling the operating state of the hydraulic actuator. When the K0 clutch 20 receives a K0 oil pressure PRk0 regulated by the hydraulic control circuit 56 and supplied to the hydraulic actuator, the K0 torque Tk0, which is the torque capacity of the K0 clutch 20, is changed, thereby switching the control state of the K0 clutch 20.

[0022] When the K0 clutch 20 is engaged, the pump wheel 22a and the engine 12 are rotated integrally via the engine connecting shaft 34. That is, when engaged, the K0 clutch 20 connects the engine 12 and the drive wheels 14 so that power can be transmitted between them. On the other hand, when the K0 clutch 20 is disengaged, power transmission between the engine 12 and the pump wheel 22a is interrupted. That is, when disengaged, the K0 clutch 20 disconnects the engine 12 and the drive wheels 14. Because the electric motor MG is connected to the pump wheel 22a, the K0 clutch 20 is provided in the power transmission path between the engine 12 and the electric motor MG and functions as a clutch that connects and disconnects the power transmission path, i.e., a clutch that connects and disconnects the engine 12 and the electric motor MG. That is, the K0 clutch 20 is a connecting / disconnecting clutch that connects the engine 12 and the electric motor MG when engaged and disconnects the connection between the engine 12 and the electric motor MG when disengaged.

[0023] 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 drive 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. Similarly, the power output from the electric motor MG is transmitted from the electric motor connecting shaft 36 to the drive 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.

[0024] The vehicle 10 is equipped with a MOP 58 which is a mechanical oil pump, an EOP 60 which is an electric oil pump, a pump motor 62, etc. The MOP 58 is connected to the pump impeller 22a and is driven to rotate by a driving power source (the engine 12, the electric motor MG) to discharge hydraulic oil used in the power transmission device 16. The pump motor 62 is a motor dedicated to the EOP 60 for driving the EOP 60 to rotate. The EOP 60 is driven to rotate by the pump motor 62 to discharge hydraulic oil. The hydraulic oil discharged by the MOP 58 and the EOP 60 is supplied to a hydraulic control circuit 56. The hydraulic control circuit 56 supplies hydraulic pressures PRcb, K0 hydraulic pressure PRk0, LU hydraulic pressure PRlu, etc., which are adjusted based on the hydraulic oil discharged by at least one of the MOP 58 and the EOP 60.

[0025] The vehicle 10 further includes an electronic control unit 90 including a control device related to driving control of the vehicle 10. The electronic control unit 90 includes a so-called microcomputer equipped with, for example, a CPU, RAM, ROM, an input / output interface, etc., and the CPU executes various controls of the vehicle 10 by performing signal processing in accordance with programs stored in the ROM in advance while utilizing the temporary storage function of the RAM. The electronic control unit 90 includes computers for engine control, electric motor control, hydraulic control, etc. as necessary.

[0026] The electronic control device 90 receives various signals based on detected values ​​from various sensors provided in the vehicle 10 (for example, an engine rotation speed sensor 70, a turbine rotation speed sensor 72, an output rotation speed sensor 74, an MG rotation speed sensor 76, an accelerator opening sensor 78, a throttle opening sensor 80, a brake switch 82, a battery sensor 84, an oil temperature sensor 86, a shift position sensor 88), and the like (for example, an engine rotation speed Ne which is the rotation speed of the engine 12, a turbine rotation speed Nt which is the same value as the AT input rotation speed Ni, an AT output rotation speed No corresponding to the vehicle speed V, an MG rotation speed Nm which is the rotation speed of the electric motor MG, a driver's The signals supplied include accelerator opening θacc, which is the amount of operation of the accelerator pedal 42 by the driver and indicates the magnitude of the acceleration operation; throttle opening θth, which is the opening of the electronic throttle valve; brake-on signal Bon, which is a signal indicating the state in which the brake pedal 44 for activating the wheel brakes is being operated by the driver; battery temperature THbat, battery charge / discharge current Ibat, and battery voltage Vbat of the battery 54; hydraulic oil temperature THoil, which is the temperature of the hydraulic oil in the hydraulic control circuit 56; and shift operation position Psh, which is the operating position of the shift lever 48 of the shift operation device 46 operated by the driver.

[0027] The shift operation device 46 is configured to be switchable among five shift operation positions Psh, including a P position, an R position, an N position, a D position, and an S position, depending on the operating position of the shift lever 48.

[0028] The P position is a shift operation position Psh for switching the power transmission device 16 to the P range (parking range). That is, when the shift operation position Psh is switched to the P position, the power transmission device 16 is switched to the P range (parking range). At this time, the power transmission path of the power transmission device 16 is interrupted, and the power transmission device 16 enters a parking state in which a lock gear mechanically connected to the drive wheels 14 is locked so as not to rotate. The operation of switching to the P position is substantially the same as the operation of switching the power transmission device 16 to the P range.

[0029] The R position is a shift operation position Psh for switching the power transmission device 16 to the R range (reverse range), which is a reverse driving range. In other words, when the shift operation position Psh is switched to the R position, the power transmission device 16 is switched to the R range. At this time, a power transmission path for reverse driving is formed in the power transmission device 16, making reverse driving possible. The operation of switching to the R position is substantially the same as the operation of switching the power transmission device 16 to the R range.

[0030] The N position is a shift operation position Psh for switching the power transmission device 16 to N range (neutral range). That is, when the shift operation position Psh is switched to the N position, the power transmission device 16 is switched to the N range. At this time, the power transmission device 16 enters a neutral state in which the power transmission path is interrupted. The operation of switching to the N position is substantially the same as the operation of switching the power transmission device 16 to the N range.

[0031] The D position is a shift operation position Psh for switching the power transmission device 16 to the D range (drive range), which is a forward driving range. In other words, when the shift operation position Psh is switched to the D position, the power transmission device 16 is switched to the D range. At this time, a power transmission path for forward driving is formed in the power transmission device 16, making forward driving possible. The operation of switching to the D position is substantially the same as the operation of switching the power transmission device 16 to the D range.

[0032] The S position is a shift operation position Psh for switching the automatic transmission 24 to an S range (sequential range) that can be shifted by manual operation by the driver. That is, when the shift operation position Psh is switched to the S position, the power transmission device 16 is switched to the S range. At this time, a gear stage of the automatic transmission 24 is selected in response to an upshift operation or a downshift operation by the driver via the shift lever 48, and the automatic transmission 24 is shifted to the selected gear stage. The operation of switching to the S position is substantially the same as the operation of switching the power transmission device 16 to the S range.

[0033] The electronic control device 90 outputs various command signals (e.g., an engine control command signal Se for controlling the engine 12, an MG control command signal Sm for controlling the electric motor MG, a CB hydraulic control command signal Sbc for controlling the engagement device CB, a K0 hydraulic control command signal Sko for controlling the K0 clutch 20, an LU hydraulic control command signal Slu for controlling the LU clutch 40, an EOP control command signal Seop for controlling the EOP 60, etc.) to each device provided in the vehicle 10 (e.g., the engine control device 50, the inverter 52, the hydraulic control circuit 56, the pump motor 62, etc.).

[0034] The electronic control device 90 includes a hybrid control means or hybrid control unit 92, a clutch control means or clutch control unit 94, and a gear shift control means or gear shift control unit 96 in order to realize various controls in the vehicle 10.

[0035] The hybrid control unit 92 has a function as an engine control means, i.e., an engine control unit 92a, that controls the operation of the engine 12, and a function as 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 using these control functions.

[0036] The hybrid control unit 92 calculates the drive amount required by the driver for the vehicle 10, for example, by applying the accelerator opening θacc and the vehicle speed V to a required drive amount map. The required drive amount map is a relationship that is experimentally or design-based and stored in advance, i.e., a predetermined relationship. The required drive amount is, for example, the required drive torque Trdem at the drive wheels 14. In other words, the required drive torque Trdem [Nm] is the required drive power Prdem [W] at the current vehicle speed V. The required drive 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. When calculating the required drive amount, the AT output rotation speed No, or the like, can be used instead of the vehicle speed V.

[0037] The hybrid control unit 92 calculates a target engine torque Tedem for the engine 12 and a target MG torque Tmdem for the electric motor MG that realize the required drive torque Trdem, taking into consideration transmission loss, the auxiliary load, the gear ratio γat of the automatic transmission 24, the chargeable power Win and dischargeable power Wout of the battery 54, etc. The hybrid control unit 92 outputs an engine control command signal Se for the engine 12 that outputs the calculated target engine torque Tedem to the engine control device 50. The hybrid control unit 92 also outputs an MG control command signal Sm for the electric motor MG that outputs the calculated target MG torque Tmdem to the inverter 52. The engine control command signal Se is, for example, a command value for engine power Pe, which is the power of the engine 12 that outputs the target engine torque Tedem at a current engine rotation speed Ne. The MG control command signal Sm is, for example, a command value for power consumption Wm of the electric motor MG that outputs the target MG torque Tmdem at a current MG rotation speed Nm.

[0038] The chargeable power Win of the battery 54 is the maximum power that can be input, which defines a 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 defines a 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 state-of-charge value SOC of the battery 54 is a value that indicates the state of charge (charge amount, remaining charge) of the battery 54, and is calculated by the electronic control device 90 based on, for example, the battery charge / discharge current Ibat and the battery voltage Vbat.

[0039] 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 motor drive (hereinafter referred to as BEV drive) mode. In the BEV drive mode, the hybrid control unit 92 performs BEV drive, in which the vehicle runs using only the electric motor MG as a drive power source with the K0 clutch 20 in a 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 engine drive mode, i.e., hybrid drive (hereinafter referred to as HEV drive) mode.

[0040] In the HEV driving mode, the hybrid control unit 92 performs engine driving, i.e., HEV driving, in which the engine 12 and the electric motor MG are used as driving power sources with the K0 clutch 20 engaged. On the other hand, even if the required driving torque Trdem can be satisfied solely 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 falls below a predetermined engine start threshold or when warming up of the engine 12, etc., is required. The engine start threshold is a predetermined threshold for determining that the state of charge value SOC is such that the engine 12 must be forcibly started to charge the battery 54. In this way, the hybrid control unit 92 automatically stops the engine 12 during HEV driving, restarts the engine 12 after the engine stop, or starts the engine 12 during BEV driving, appropriately switching between the BEV driving mode and the HEV driving mode, based on the required driving torque Trdem, etc.

[0041] During coasting with the accelerator pedal 42 released, the hybrid control unit 92 executes regenerative control to rotate the electric motor MG using the driven torque transmitted from the drive wheels 14 to generate electricity. The electric power generated by regeneration is charged into the battery 54 via the inverter 52. When braking by depressing the brake pedal 44, the braking force distribution between the braking force by the hydraulic brakes provided on each wheel and the braking force by the regeneration of the electric motor MG is appropriately adjusted so that a braking force corresponding to the amount of operation of the brake pedal 44 is obtained.

[0042] The clutch control unit 94 controls the K0 clutch 20 in accordance with the driving mode during driving. For example, when it is determined that the driving mode is to be switched to the HEV driving mode during BEV driving, the clutch control unit 94 controls the engagement of the K0 clutch 20 so as to execute start control of the engine 12. For example, when it is determined that there is a request to start the engine 12 based on the driving state, the clutch control unit 94 outputs a K0 hydraulic control command signal Sko to the hydraulic control circuit 56 to control the K0 clutch 20 from a released state toward an engaged state so as to obtain a K0 torque Tk0 for transmitting to the engine 12 a torque required for cranking the engine 12, which is a torque that increases the engine rotation speed Ne.

[0043] The shift control unit 96 determines whether to shift the automatic transmission 24 based on, for example, a shift map in which predetermined shift conditions are defined, and outputs a CB hydraulic pressure control command signal Scb to the hydraulic control circuit 56 as necessary to execute shift control of the automatic transmission 24. During a shift transition period, control is performed so that the hydraulic pressure PRcb1 supplied to the engagement side engagement device CB1 that is engaged during the shift is increased, and the hydraulic pressure PRcb2 supplied to the release side engagement device CB2 that is released during the engagement is decreased.

[0044] The shift map is a predetermined relationship having shift lines for determining whether to shift gears in the automatic transmission 24 on a two-dimensional coordinate system using, for example, vehicle speed V and accelerator pedal position θacc as variables. For example, when the vehicle speed V or accelerator pedal position θacc changes while traveling and the traveling state crosses a shift line defined on the relationship map, it is determined that the shift conditions are met and the gear is changed. In the shift map, the AT output rotation speed No or the like may be used as a value related to the vehicle speed V instead of the vehicle speed V, and the required drive torque Trdem, required drive force Frdem, throttle position θth or the like may be used as a value related to the accelerator pedal position θacc instead of the accelerator pedal position θacc. The automatic transmission 24 shifts gears based on the shift map in which the shift conditions are defined when the shift operation position Psh is in the D position. The mode in which the gear position of the automatic transmission 24 is established based on such a shift map (shift conditions) is defined as a first shift mode M1.

[0045] Furthermore, when the shift operation position Psh is switched to the S position, the shift control unit 96 makes a shift decision based on the upshift operation and downshift operation by the driver via the shift lever 48, and outputs a CB hydraulic control command signal Scb to the hydraulic control circuit 56 to execute shift control to the gear selected by the driver. This mode in which the shift operation position Psh is switched to the S position and the gear is established based on manual operation by the driver is defined as a second shift mode M2.

[0046] While the shift position Psh is in the D position and the accelerator pedal 42 is released while the vehicle is running in a regenerative mode with the electric motor MG regenerating power (regenerative coasting), a determination may be made to downshift the automatic transmission 24 as the vehicle speed V decreases. In this case, the shift control unit 96 downshifts the automatic transmission 24 in parallel with the regeneration by the electric motor MG. In such a downshift with regeneration, the shift time is set longer to prioritize suppression of shock. If the driver switches the shift position Psh from the D position to the S position during a downshift with regeneration, i.e., from the first shift mode M1 (D range) to the second shift mode M2 ​​(S range), the shift must be completed quickly to achieve the deceleration desired by the driver. However, in conventional systems, the same hydraulic control was executed regardless of whether or not the shift to the S range was performed, resulting in a change in the shift time and making it impossible to quickly achieve the deceleration desired by the driver.

[0047] In contrast, when a downshift of the automatic transmission 24 is executed during regenerative traveling in which the vehicle is traveling with regeneration by the electric motor MG, and when the driver switches to the S range (second shift mode M2) before the inertia phase starts, the shift control unit 96 switches the sweep amount of the hydraulic pressure PRcb1 of the engagement-side engagement device CB1 during the inertia phase and the timing at which the sweep starts. When a downshift is started during regenerative traveling in which the vehicle is traveling with regeneration by the electric motor MG, the shift control unit 96 determines whether the shift operation position Psh has been switched from the D position to the S position, that is, whether the shift mode has been switched from the first shift mode M1 (D range) to the second shift mode M2 ​​(S range), until the inertia phase starts. If the gear shift control unit 96 detects a driver's switching operation to the S position before the inertia phase starts, it determines that the mode has been switched to the second gear shift mode M2 ​​(S range), and makes the timing for starting the sweep of the hydraulic pressure PRcb1 of the engagement side engagement device CB (hereinafter referred to as engagement side engagement device CB1) during the inertia phase earlier than when switching to the second gear shift mode M2 ​​is not possible. Furthermore, the gear shift control unit 96 increases the sweep amount, which is the amount of change per unit time of the hydraulic pressure PRcb1 of the engagement side engagement device CB1 during the inertia phase, compared to when switching to the second gear shift mode M2 ​​is not possible.

[0048] The shift control section 96 stores a first shift mode map (D range map) that defines the hydraulic pressure PRcb1 (command pressure) of the engagement side engagement device CB1 during the inertia phase when the mode cannot be switched to the second shift mode M2 ​​(S range) before the inertia phase starts, and a second shift mode map (S range map) that defines the hydraulic pressure PRcb1 of the engagement side engagement device CB1 during the inertia phase when the mode is switched to the second shift mode M2 ​​before the inertia phase starts. If the mode is not switched to the second shift mode M2 ​​before the inertia phase starts, the shift control section 96 sets the hydraulic pressure PRcb1 (command value) based on the first shift mode map (D range map), and if the mode is switched to the second shift mode M2, it sets the hydraulic pressure PRcb1 of the engagement side engagement device CB1 based on the second shift mode map (S range map).

[0049] Here, the second shift mode map (S range map) has an earlier sweep start point (start timing) for the oil pressure PRcb1 of the on-coming engagement device CB1 than the first shift mode map (D range map). Furthermore, the second shift mode map has a larger sweep amount for the oil pressure PRcb1 of the on-coming engagement device CB1 during the inertia phase than the first shift mode map. As a result, when the hydraulic control circuit 56 is controlled so that the oil pressure PRcb1 of the on-coming engagement device CB1 during the inertia phase becomes equal to the value set based on the second shift mode map, the turbine rotation speed Nt quickly synchronizes with the synchronous rotation speed Nsyc after the downshift, and the shift time required to complete the downshift is shortened.

[0050] FIG. 3 is a time chart illustrating the control state when switching from the first shift mode M1 (D range) to the second shift mode M2 ​​(S range) during a downshift involving regeneration. FIG. 3 shows an example of a downshift from third gear 3rd to second gear 2nd. In FIG. 3, the horizontal axis represents time t [ms], and the vertical axis represents, from top to bottom, the gear, the shift operation position Psh, the turbine rotation speed Nt [rpm], and the hydraulic pressure PRc1 [Pa] (indicated pressure) of the clutch C1, which is the engagement-side engagement device CB1 engaged during the downshift. The turbine rotation speed Nt can be interpreted as the AT input rotation speed Ni of the automatic transmission 24, and the shift operation position Psh can be interpreted as the shift range of the power transmission device 16. In addition, in FIG. 3, the oil pressure PRc1 indicated by the solid line and set after time t3 corresponds to the command pressure set based on the map for the first shift mode described above, and the oil pressure PRc1 indicated by the dashed line and set after time t3 corresponds to the command pressure set based on the map for the second shift mode described above.

[0051] First, we will explain the case where switching to the second shift mode M2 ​​(S range) is not performed during a downshift. The behavior when switching to the second shift mode M2 ​​is not performed is shown by the solid line in Figure 3. At time t1 in Figure 3, a downshift from third gear (3rd) to second gear (2nd) is determined due to a decrease in vehicle speed V during regenerative driving, and a gear change is initiated. At this time, a quick apply is performed, temporarily increasing the hydraulic pressure PRc1 of the clutch C1, and then the clutch C1 waits for a predetermined time at a predetermined standby pressure PRstd. The standby pressure PRstd is set, for example, to the hydraulic pressure (also known as packing pressure) at which the clutch C1 is about to begin to exert its torque capacity. At time t2, after the predetermined time has elapsed, the hydraulic pressure PRc1 of the clutch C1 gradually increases by a predetermined sweep amount. Here, the sweep amount corresponds to the amount of change (increase) in hydraulic pressure per unit time. The larger the sweep amount, the steeper the slope of the hydraulic pressure PRc1 after time t2. At time t3, the oil pressure PRc1 of the clutch C1 is temporarily maintained at a constant pressure, and then at time t3a, a predetermined time after time t3, the oil pressure PRc1 is gradually increased by a predetermined sweep amount. As a result, after a predetermined time has elapsed from time t3a, the turbine rotation speed Nt increases, and at time t4b, the oil pressure PRcb1 is increased until it reaches a level at which the clutch C1 is fully engaged.

[0052] Next, a case where the mode is switched to the second shift mode M2 ​​(S range) during a downshift will be described. FIG. 3 shows, as an example, a case where the mode is switched to the second shift mode M2 ​​at time ts, which corresponds to the torque phase after time t2. At time ts, a predetermined time after time t2, the mode is switched from the first shift mode M1 (D range) to the second shift mode M2 ​​(S range). In connection with the switch to the second shift mode M2, the hydraulic pressure PRc1 of the clutch C1 is controlled thereafter based on a second shift mode map.

[0053] When the mode is switched to the second shift mode M2 ​​(S range) at time ts before the start of the inertia phase, the sweep of the hydraulic pressure PRc1 is started at time t3. As shown in Fig. 3, when the mode is switched to the second shift mode M2 ​​(S range), the timing at which the sweep starts is advanced by a time Δt from the start of the sweep at time t3a based on the first shift mode map.

[0054] Furthermore, when the mode is switched to the second shift mode M2, the sweep amount during the inertia phase is increased compared to when the mode is not switched to the second shift mode M2. For example, when comparing the rate of increase α of the hydraulic pressure PRcb, which correlates with the sweep amount corresponding to the change (increase) in the hydraulic pressure PRcb (command pressure) per unit time at a predetermined time tx during the inertia phase, the rate of increase α is αd when the mode is not switched to the second shift mode M2, whereas the rate of increase αs is αs when the mode is switched to the second shift mode M2. As shown in FIG. 3, the rate of increase αs when the mode is switched to the second shift mode M2 ​​is greater than the rate of increase αd when the mode is not switched to the second shift mode M2. In other words, when the mode is switched to the second shift mode M2, the sweep amount (amount of change per unit time) of the hydraulic pressure PRc1 of the clutch C1 during the inertia phase is increased compared to when the mode is not switched to the second shift mode M2. As a result, when the mode is switched to the second speed change mode M2, the timing at which the turbine rotation speed Nt starts to increase is earlier than when the mode is not switched to the second speed change mode M2. As a result, when the mode is switched to the second speed change mode M2, the downshift is completed more quickly than when the mode is not switched to the second speed change mode M2, and the deceleration due to the downshift can be obtained earlier.

[0055] 4 is a flowchart illustrating the main control operations of the electronic control unit 90, which are performed to quickly complete a gear shift when a switching operation to the second shift mode M2 ​​(S range) is performed during a downshift involving regeneration. This flowchart is repeatedly executed while the vehicle is traveling.

[0056] First, in step S10 (hereinafter, the term "step" will be omitted) corresponding to the control function of the shift control unit 96, it is determined whether the automatic transmission 24 is currently downshifting with regeneration by the electric motor MG. If the determination in S10 is negative, this routine is terminated. If the determination in S10 is positive, it is determined in S20 corresponding to the control function of the shift control unit 96 whether the first shift mode M1 (D range) has been switched to the second shift mode M2 ​​(S range) before the start of the inertia phase. If the mode has not been switched to the second shift mode M2 ​​before the start of the inertia phase, or if the mode has been switched to the second shift mode M2 ​​but is still in the inertia phase, the determination in S20 is negative.

[0057] If the determination in S20 is negative, in S50, which corresponds to the control function of the gear shift control unit 96, the sweep start point (sweep start timing) and sweep amount of the oil pressure PRcb1 of the on-coming engagement device CB1 are set when switching to the second gear shift mode M2 ​​(S range) is not possible, i.e., when in the first gear shift mode M1 (D range). In other words, the sweep start point and sweep amount of the oil pressure PRcb1 of the on-coming engagement device CB1 are set based on the first gear shift mode map (D range map) that is applied when switching to the second gear shift mode M2 ​​is not possible. Next, in S60, which corresponds to the control function of the gear shift control unit 96, the oil pressure PRcb1 of the on-coming engagement device CB1 is controlled to have the sweep start point and sweep amount of the oil pressure PRcb1 of the on-coming engagement device CB1 set in S50.

[0058] On the other hand, if the determination in S20 is positive, in S30, which corresponds to the control function of the gear shift control unit 96, the sweep start point (i.e., sweep start timing) and sweep amount of the oil pressure PRcb1 of the on-coming engagement device CB1 when switched to second shift mode M2 ​​are set. In other words, the sweep start point and sweep amount of the oil pressure PRcb1 of the on-coming engagement device CB1 are set based on the second shift mode map (S range map) that is applied when switched to second shift mode M2. Next, in S40, which corresponds to the control function of the gear shift control unit 96, the oil pressure PRcb1 of the on-coming engagement device CB1 is controlled so that the sweep start point and sweep amount of the oil pressure PRcb1 of the on-coming engagement device CB1 become the ones set in S30.

[0059] By controlling as described above, when the mode is switched to the second speed change mode M2 ​​before the start of the inertia phase, the sweep start point and sweep amount of the oil pressure PRcb1 of the engagement side engagement device CB1 are set based on the second speed change mode map, and the sweep start point (i.e., sweep start timing) is advanced and the sweep amount is increased compared to when the mode is not switched to the second speed change mode M2. As a result, the timing at which the turbine rotation speed Nt starts to increase is advanced and the speed change time is shortened.

[0060] As described above, according to this embodiment, when switching to the second shift mode M2 ​​is detected during a downshift of the automatic transmission 24 involving regeneration by the electric motor MG, the amount of change per unit time in the hydraulic pressure PRcb1 of the engagement-side engagement device CB1 is increased compared to when switching to the second shift mode M2 ​​is not possible, so the inertia phase progresses more quickly and the downshift can be completed earlier than when switching to the second shift mode M2 ​​is not possible. As a result, the downshift time is shortened and the deceleration requested by the driver can be achieved earlier.

[0061] Although the embodiments of the present invention have been described in detail above with reference to the drawings, the present invention can also be applied to other embodiments.

[0062] For example, in the above-described embodiment, when the mode is switched to the second shift mode M2 ​​during a downshift, the start point of the sweep of the hydraulic pressure PRcb1 of the engagement side engagement device CB1 is advanced and the sweep amount is increased compared to when the mode is not switched to the second shift mode M2. However, in the present invention, it is not necessary to perform both of these. For example, it is also acceptable to increase only the sweep amount of the hydraulic pressure PRcb1. Even when only the sweep amount is increased, the progression of the inertia phase is accelerated, thereby shortening the shift time.

[0063] In the above-described embodiment, the mode is switched to the second speed change mode M2 ​​during the torque phase in which the hydraulic pressure PRc1 of the clutch C1, which is the on-coming engagement device, is gradually increasing in the time chart of Fig. 3, but the present invention is not necessarily limited to this. For example, the present invention can be applied even when the mode is switched to the second speed change mode M2 ​​in a state in which the standby pressure PRstd after the quick apply is maintained. In short, the present invention can be applied as appropriate as long as it is before the start of the inertia phase.

[0064] 3 illustrates a case in which the second shift mode M2 ​​is switched to during a downshift from third gear 3rd to second gear 2nd. However, the present invention is not necessarily limited to a downshift from third gear 3rd to second gear 2nd. For example, the present invention can also be applied to a downshift from second gear 2nd to first gear 1st. In this regard, the engagement side engagement device CB1 engaged during a downshift is not limited to the clutch C1, and can be changed as appropriate depending on the gear being shifted, such as the clutch C2.

[0065] In the above-described embodiment, when the mode is switched to the second shift mode M2, the gear position of the automatic transmission 24 is determined by manual operation by the driver, but the present invention is not limited to this. For example, the upper limit of the gear positions to which the automatic transmission 24 can be shifted may be determined by manual operation by the driver.

[0066] It should be noted that the above is merely one embodiment, and the present invention can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art. [Explanation of symbols]

[0067] 10: Vehicle (hybrid vehicle) 12: Engine 14: Drive wheel 24: Automatic transmission (transmission) MG: Electric motor CB1: Engagement side engagement device M1: First gear shift mode M2: Second gear shift mode

Claims

[Claim 1] A control device for a hybrid vehicle, which is applied to a hybrid vehicle including an engine, an electric motor, and a transmission provided in a power transmission path between the engine, the electric motor, and drive wheels, wherein the transmission is configured to be switchable between a first shift mode in which a gear is established based on predetermined shift conditions, and a second shift mode in which a gear is established based on manual operation by a driver, and is configured to increase a command pressure of an engagement-side engagement device that is engaged during a shift during a shift transition period, When a downshift is executed based on the first speed change mode during regenerative running in which the vehicle is running with regeneration by the electric motor, and when the driver switches to the second speed change mode before the start of an inertia phase, the amount of change per unit time of the command pressure of the engagement-side engagement device during the inertia phase is increased compared to when the mode cannot be switched to the second speed change mode. A control device for a hybrid vehicle.

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