Control device and control method for a hybrid vehicle

Abstract

A control device for a hybrid vehicle, the hybrid vehicle (10; 210) comprising an engine (12) with a supercharger (SC) serving as a travel drive power source, a rotary machine (MG2; MG) serving as another travel drive power source, an energy storage device (54) configured to transmit and receive electric power to and from the rotary machine (MG2; MG), and a transmission (60; 262) provided in a power transmission path between the engine (12) and drive wheels (16) and between the rotary machine (MG2; MG) and the drive wheels (16), the control device (100; 200) comprising: a prediction unit (104) configured to predict whether a necessary discharge power (Wnd) from the energy storage device (54) required to perform a downshift in the transmission (60; 262) exceeds an upper limit of the discharge power (Wout) of the energy storage device (54) when the downshift in the transmission (60; 262) is performed in a hybrid vehicle driving mode; and a control unit (106) configured to control a compressor speed (Ncmp) such that an increase rate (ΔNcmp) of the compressor speed (Ncmp) of the supercharger (SC) at the time of downshifting in the transmission (60; 262) increases as the upper limit of the discharge power (Wout) decreases when the necessary discharge power (Wnd) is predicted to exceed the upper limit of the electrical discharge power (Wout).

Description

Background of the invention 1. Field of the invention

[0001] The invention relates to a control device and a control method for a hybrid vehicle having an engine with a supercharger and a rotary machine as travel drive power sources and a transmission in a power transmission path between the engine and the drive wheels and between the rotary machine and the drive wheels. 2. Description of the state of the art

[0002] A control device for a hybrid vehicle is known, which includes an engine with a supercharger, a rotating machine, and an energy storage device that transmits and receives electric power to and from the rotating machine using the power output from the engine and the rotating machine as traction power, as well as a transmission in a power transmission path between the engine and the drive wheels and between the rotating machine and the drive wheels. One example is a control device for a hybrid vehicle described in JP 2015-214184 A.

[0003] Furthermore, DE 11 2011 104 907 T5 discloses a control unit for a (hybrid) vehicle drive system comprising an internal combustion engine, an electric motor, a battery, a transmission, and an air conditioning compressor. The control unit includes a first map in which a pure electric motor drive permission range is set according to a state of charge of the battery, and a second map in which the pure electric motor drive permission range of the first map is restricted, wherein drive control is performed by selecting to refer to the second map instead of the first map when the air conditioning compressor is actuated.

[0004] Furthermore, DE 10 2018 201 584 A1 discloses a hybrid vehicle having an internal combustion engine, an electric compressor, a generator, a battery, and an energization control device. The energization control device is configured to be able to select two control modes, that is, a supercharging mode and an electric power consumption mode. The supercharging mode is a control mode in which the energization control device controls the energization to the electric compressor to rotate the electric compressor to supercharge intake air.The electric power consumption mode is a control mode in which the energization control device controls the energization to the electric compressor to deteriorate engine efficiency compared to the supercharging mode to increase electric power consumption of the electric compressor. The energization control device is configured to supply the regenerated electric power to the electric compressor and control the energization to the electric compressor with the electric power consumption mode when regenerative braking is performed by using the generator and the regenerated electric power for obtaining a regenerative braking force required is more than an input limit level of the battery.

[0005] Furthermore, JP 2009-126258 A discloses a vehicle comprising an electric motor capable of outputting power for driving the vehicle, power storage means capable of exchanging power with the electric motor, a plurality of accessories driven by power from a power system including the power storage means, required driving force setting means for setting a required driving force required for driving, and, when acceleration is required, control means for controlling the electric motor and the plurality of accessories so that the vehicle travels with a driving force based on the set required driving force, and the power supply to at least some of the plurality of accessories is limited in accordance with a power limiting order.which corresponds to the order of the accessories to which the energy supply is limited among the multitude of accessories. Summary of the invention

[0006] When an energy storage device is subjected to a discharge limitation by using an upper limit of the electric discharge power, the necessary discharge power from the energy storage device required to perform a downshift in a transmission may exceed the upper limit of the electric discharge power. JP 2015 - 214 184 A discloses that, when the necessary discharge power is predicted to exceed the upper limit of the electric discharge power at the time a downshift is performed in a transmission, a time required for the downshift to proceed is adjusted based on a predicted power surplus.However, in the control device described in JP 2015 - 214 184 A, deterioration in gear shift responsiveness may be caused because the time required for downshifting to proceed becomes longer as the predicted power surplus increases.

[0007] It is therefore an object of the invention to provide a control apparatus and a control method for a hybrid vehicle which can prevent the necessary discharge power required when a downshift is performed in a transmission from exceeding an upper limit of the electric discharge power and which can mitigate deterioration in the response of the gear shift.

[0008] This object is achieved by the control device according to the independent patent claim and by a control method according to the independent patent claim. Advantageous developments of the invention are described in the subclaims.

[0009] According to a first aspect of the invention, a control device for a hybrid vehicle is provided, which includes an engine with a supercharger serving as a traction drive power source, a rotary machine serving as a traction drive power source, an energy storage device configured to transmit and receive electric power to and from the rotary machine, and a transmission provided in a power transmission path between the engine and drive wheels and between the rotary machine and the drive wheels. The control device includes a prediction unit and a control unit.The prediction unit is configured to predict whether a required discharge power from the energy storage device required to perform a downshift in the transmission exceeds the upper limit of the electric discharge power of the energy storage device when the downshift in the transmission is performed in a hybrid vehicle traveling mode (hereinafter referred to as an HV traveling mode). The control unit is configured to control a compressor speed such that an increase rate of the compressor speed of the supercharger at the time the downshift in the transmission is performed increases as the upper limit of the discharge power decreases when the required discharge power is predicted to exceed the upper limit of the electric discharge power.

[0010] The control device for a hybrid vehicle according to the first aspect of the invention includes the prediction unit that predicts whether the necessary discharge power from the energy storage device required to perform a downshift in the transmission exceeds the upper limit of the electric discharge power of the energy storage device when a downshift in the transmission is performed in the HV traveling mode, and includes the control unit that controls the compressor speed so that an increase rate of the compressor speed of the supercharger at the time the downshift in the transmission is performed increases as the upper limit of the discharge power decreases when the necessary discharge power is predicted to exceed the upper limit of the electric discharge power.When downshifting is performed in the transmission, as the upper limit of the discharge power of the energy storage device decreases, the increase rate of the compressor speed of the supercharger increases, a response delay of the boost pressure decreases, and an increase rate of engine torque increases. Accordingly, it is possible to dampen an amount of assist torque of the rotating machine required to increase an input speed of the transmission and reduce the necessary discharge power from the energy storage device to the rotating machine.Consequently, it is possible to prevent the necessary discharge power from the energy storage device, which is required when downshifting is performed in the transmission, from exceeding the upper limit of the electric discharge power of the energy storage device, and it is possible to dampen the deterioration in the gearshift response.

[0011] In the control device for a hybrid vehicle according to the first aspect, the control unit may be configured to control the compressor speed so that the increase rate of the compressor speed increases as a target boost pressure increases.

[0012] In the control device for a hybrid vehicle having this configuration, the control unit further controls the compressor speed so that the increase rate of the compressor speed increases as the target boost pressure increases. As the target boost pressure increases, the increase rate of the compressor speed of the supercharger increases, and the boost pressure increases faster. When downshifting in the transmission is performed as the target boost pressure increases, the increase rate of the compressor speed increases, the increase rate of the boost pressure becomes more appropriate, and the response delay of the boost pressure decreases. Accordingly, it is possible to prevent the necessary discharge power from the energy storage device, which is required when downshifting in the transmission, from exceeding the upper limit of the electric discharge power of the energy storage device, and it is possible to mitigate the deterioration in the gearshift response.

[0013] In the control device for a hybrid vehicle according to the first aspect, the prediction unit may be configured to estimate the necessary discharge power using a map in which a relationship between a combination type / possibility of gear stages before and after the downshift is performed in the transmission and the necessary discharge power is determined in advance.

[0014] In the control device for a hybrid vehicle having this configuration, the prediction unit estimates the required discharge power using the map in which the relationship between a combination type of gear stages before and after performing the downshift in the transmission and the required discharge power is determined in advance. By using the map in this way, it is possible to estimate the required discharge power before performing the downshift.

[0015] In the control device for a hybrid vehicle according to the first aspect, the supercharger may include at least one electric supercharger, and the compressor speed of the supercharger may be a speed of an electric compressor included in the electric supercharger.

[0016] In the control device for a hybrid vehicle having this configuration, the supercharger includes at least one electric supercharger, and the compressor speed of the supercharger is set as the electric compressor speed of the supercharger. Accordingly, for example, by controlling the speed of the electric motor connected to the electric compressor, the speed of the electric compressor, which is the compressor speed of the supercharger, is controlled.

[0017] In the control device for a hybrid vehicle according to the first aspect, the upper limit of the discharge power may be configured to be determined based on a temperature and a state of the charge value / state of charge value of the energy storage device.

[0018] In the control device for a hybrid vehicle having this configuration, the upper limit of the discharge power is determined based on the temperature and the state of the charge level of the energy storage device. Accordingly, it is possible to mitigate the progression of deterioration of the energy storage device and determine the upper limit of the electric discharge power according to the need / necessity for charging the energy storage device.

[0019] In the control device for a hybrid vehicle according to the first aspect, the upper limit of the discharge power may be configured to be determined to decrease as a degree of deterioration of the energy storage device increases.

[0020] In the control device for a hybrid vehicle having this configuration, it is determined that the upper limit of the discharge power decreases as the degree of deterioration of the energy storage device increases. By determining that the upper limit of the discharge power of the energy storage device decreases as the degree of deterioration of the energy storage device increases, it is possible to limit the charge / discharge power of the energy storage device and thus mitigate the progression of deterioration of the energy storage device.

[0021] In the control device for a hybrid vehicle according to the first aspect, the control unit may be configured to control the compressor speed so that the increase rate of the compressor speed of the supercharger at the time when the downshift is performed in the transmission increases as the upper limit of the discharge power decreases, if the upper limit of the discharge power is limited to be less than a predetermined determination power value.

[0022] In the control device for a hybrid vehicle having this configuration, when the upper limit of the discharge power is limited to be lower than the predetermined determination power value, the control unit controls the compressor speed so that the increase rate of the compressor speed of the supercharger at the time of performing the downshift in the transmission increases as the upper limit of the discharge power decreases. This is because there is a possibility that the required discharge power will exceed the upper limit of the electric discharge power when the upper limit of the discharge power is limited.

[0023] According to a second aspect of the invention, there is provided a control method for a hybrid vehicle, which includes an engine with a supercharger serving as a traction drive power source, a rotary machine serving as a traction drive power source, an energy storage device configured to transmit and receive electric power to and from the rotary machine, and a transmission provided in a power transmission path between the engine and drive wheels and between the rotary machine and the drive wheels.The control method includes: predicting whether a necessary discharge power from the energy storage device required to perform a downshift in the transmission exceeds an upper limit of the discharge power of the energy storage device when the downshift in the transmission is performed in a hybrid vehicle traveling mode; and controlling a compressor speed so that an increase rate of the compressor speed of the supercharger at the time of performing the downshift in the transmission increases as the upper limit of the discharge power decreases when the necessary discharge power is predicted to exceed the upper limit of the electric discharge power.

[0024] With the control method for a hybrid vehicle according to the second aspect, when downshifting is performed in the transmission, the increase rate of the compressor speed of the supercharger increases, the response delay of the boost pressure decreases, and the increase rate of the engine torque increases as the upper limit of the discharge power of the energy storage device decreases. Accordingly, it is possible to dampen an amount of assist torque of the rotating machine required to increase an input speed of the transmission, and it is possible to reduce the necessary discharge power from the energy storage device to the rotating machine.Consequently, it is possible to prevent the necessary discharge power from the energy storage device, which is required when the downshift is performed in the transmission, from exceeding the upper limit of the electric discharge power of the energy storage device, and it is possible to dampen the deterioration of the gearshift response. Short description of the drawings

[0025] Features, advantages and technical and industrial significance of exemplary embodiments of the invention will be described below with reference to the accompanying drawings, in which the same reference numerals designate the same elements, and wherein: Fig. 1 is a functional block diagram schematically illustrating a configuration of a vehicle in which an electronic control unit according to a first embodiment of the invention is mounted, and illustrating principal parts of a control function for various types of control in the vehicle; Fig. 2 is a diagram schematically illustrating a configuration of an engine used in Fig. 1 is shown; Fig. 3 is a diagram illustrating an example of an optimal engine operating point in a two-dimensional coordinate system with an engine speed and an engine torque of the engine as variables; Fig. 4 is a diagram illustrating an example of a power source switching map used for switching control between electric vehicle running (hereinafter referred to as EV running) and hybrid vehicle running (hereinafter referred to as HV running) of the vehicle; Fig. 5 is an engagement operation table showing a relationship between a gear shift operation of a step gear shift unit shown in Fig. 1 and a combination of the operating states of the engagement devices used therein; Fig. 6 is a collinear diagram showing a relative relationship between the speeds of the rotating elements in a continuously variable speed gear shifting unit and a stepped speed gear shifting unit used in Fig. 1 is shown, represents; Fig. 7 is a graph showing a relationship between a discharge power of a battery used in Fig. 1 and represents an increase rate of a compressor speed of a supercharger; Fig. 8 is a graph illustrating a relationship between a target boost pressure of the charger and the increase rate of the compressor speed; Fig. 9 is a diagram showing an example of a flowchart of a principal part of a control operation of the electronic control unit; Fig. 10 is a diagram showing an example of a timing chart when the control operation of the electronic control unit shown in Fig. 9 is shown; and Fig. 11 is a functional block diagram schematically illustrating a configuration of a vehicle in which an electronic control unit according to a second embodiment of the invention is mounted, and illustrating a principal part of a control function for various types of control in the vehicle. Detailed description of the embodiments

[0026] Hereinafter, embodiments of the invention will be described in detail with reference to the accompanying drawings. In the following embodiments, the drawings are simplified or modified accordingly, and dimensional relationships, shapes, and the like of constituent elements are not necessarily depicted accurately.

[0027] Fig. 1 is a diagram schematically illustrating a configuration of a hybrid vehicle 10 in which an electronic control device 100 according to a first embodiment of the invention is mounted, and illustrating a principal part of a control function for various types of control in the hybrid vehicle 10. The hybrid vehicle 10 (hereinafter referred to as a "vehicle 10") includes an engine 12, a first rotating machine MG1, a second rotating machine MG2, a power transmission device 14, and drive wheels 16.

[0028] Fig. 2 is a diagram schematically illustrating a configuration of the engine 12. The engine 12 is a travel power source of the vehicle 10 and is a known internal combustion engine, such as a gasoline engine or a diesel engine, which has a supercharger SC, that is, an engine with the supercharger ST. The supercharger SC includes an exhaust turbine turbocharger 18 and an electric supercharger 48. An intake pipe 20 is provided in an intake system of the engine 12, and the intake pipe 20 is connected to an intake manifold 22 attached to an engine body 12a. An exhaust pipe 24 is provided in an exhaust system of the engine 12, and the exhaust pipe 24 is connected to an exhaust manifold 26 attached to the engine body 12a.

[0029] The exhaust turbine turbocharger 18 is a known exhaust turbine turbocharger that includes a compressor 18c provided in the intake pipe 20 and a turbine 18t provided in the exhaust pipe 24. The turbine 18t is rotatably driven by the exhaust gas, i.e., a flow of the exhaust gas. The compressor 18c is connected to the turbine 18t and is rotatably driven by the turbine 18t to compress the air drawn toward the engine 12, i.e., the intake air.

[0030] The electric supercharger 48 includes an electric compressor 48c provided in the intake pipe 20 upstream of the compressor 18c, and an electric motor 48m connected to the electric compressor 48c, and electrically performs supercharging / turbocharging. The electric compressor 48c is rotatably driven by the electric motor 48m to compress the intake air of the engine 12. The electric motor 48m is controlled by an electronic control device 100, which will be described later, to rotatably drive the electric compressor 48c. The electric supercharger 48 is driven, for example, to complete a response delay of the turbocharging by the exhaust turbine turbocharger 18.

[0031] An exhaust bypass 28b, which causes the exhaust gas to flow from upstream to downstream of the turbine 18t by bypassing the turbine 18t, is provided in the exhaust pipe 24. A wastegate valve 28v (hereinafter referred to as a "WGV 28v"), which continuously adjusts a ratio of the exhaust gas passing through the exhaust bypass 28b to the exhaust gas passing through the turbine 18t, is provided in the exhaust bypass 28b. A valve opening of the WGV 28v is continuously adjusted by causing the electronic control device 100, which will be described later, to operate an actuator, not shown. As the valve opening of the WGV 28v increases, the exhaust gas of the engine 12 is more likely to be discharged via the exhaust bypass 28b.Accordingly, in a turbocharging state of the engine 12 in which a turbocharging operation of the exhaust turbine turbocharger 18 operates, a boost pressure Pchg [Pa] of the supercharger SC increases as the valve opening of the WGV 28v increases. The boost pressure Pchg is an intake air pressure and is an air pressure downstream of the compressor 18c in the intake pipe 20. A side on which the boost pressure Pchg is low is, for example, an intake air pressure side in a non-charging state of the engine 12 in which the boosting operation of the supercharger SC does not operate at all, that is, an intake air pressure side in an engine without the supercharger SC.

[0032] An air cleaner / air purification device 32 is provided at an inlet of the intake pipe 20, and an air flow meter 34, which measures an amount of intake air Qair of the engine 12, is provided in the intake pipe 20 downstream of the air cleaner 32 and upstream of the electric compressor 48c. An intercooler 36, which is a heat exchanger that cools the intake air compressed by the supercharger SC by exchanging heat between the intake air and the outside air or a coolant, is provided in the intake pipe 20 downstream of the compressor 18c.An electronic throttle valve 38, whose opening and closing are controlled by causing the electronic control device 100, described later, to actuate a throttle actuator (not shown), is provided in the intake pipe 20 downstream of the intercooler 36 and upstream of the intake manifold 22. A boost pressure sensor 40 that detects the boost pressure Pchg and an intake air temperature sensor 42 that detects an intake air temperature THair [°C], which is the temperature of the intake air, are provided in the intake pipe 20 between the intercooler 36 and the electronic throttle valve 38. A throttle valve opening sensor 44 that detects a throttle valve opening Θth [%], which is an opening of the electronic throttle valve 38, is provided near the electronic throttle valve 38, for example, in the throttle actuator.

[0033] An intake bypass 46b, which causes intake air to flow from upstream to downstream of the electric compressor 48c by bypassing the electric compressor 48c, is provided in the intake pipe 20. The intake bypass 46b is connected to the intake pipe 20 upstream of the electric compressor 48c at a connecting part 46c1 and is connected to the intake pipe 20 downstream of the electric compressor 48c at a connecting part 46c2. An air bypass valve 46v, which opens and closes a passage of the intake bypass 46b between a fully open state and a fully closed state, is provided in the intake bypass 46b. The opening and closing of the air bypass valve 46v are controlled by causing the electronic control device 100, which will be described later, to operate an actuator which is not shown.For example, the air bypass valve 46v is opened so that the electric supercharger 48 is less likely to serve as a resistance to the intake air flowing through the intake pipe 20 at the time of non-actuation of the electric supercharger 48.

[0034] A low-pressure EGR device 30 is provided for recirculating a portion of the exhaust gas flowing at a relatively low pressure in the exhaust pipe 24 downstream of the turbine 18t to the intake pipe 20. The low-pressure EGR device 30 includes an EGR bypass 30b, an EGR valve 30v, and an EGR cooler 30c. The EGR bypass 30b connects the intake pipe 20 between the connecting portion 46c2 and the compressor 18c to the exhaust pipe 24 downstream of the turbine 18t and directs a portion of the exhaust gas from the exhaust pipe 24 downstream of the turbine 18t to the intake pipe 20 between the connecting portion 46c2 and the compressor 18c. Here, the exhaust gas recirculated via the EGR bypass 30b is referred to as "EGR gas." The EGR valve 30v adjusts the amount of EGR gas by changing a passage portion of the EGR bypass 30b.The EGR cooler 30c reduces the temperature of the EGR gas by exchanging heat between the EGR gas passing through the EGR cooler 30c and a coolant. For example, the valve opening of the EGR valve 30v is controlled by the electronic control device 100 to achieve a ratio of the EGR gas to a preset amount of intake air Qair according to a confirmation state of the engine 12 (for example, an engine speed Ne [rpm] and an engine load).

[0035] In the engine 12, an engine torque Te [Nm] output from the engine 12 is controlled by causing the electronic control device 100, which will be described later, to control an engine control device 50 (see FIG. Fig. 1) which comprises the electronic throttle valve 38, a fuel injection device, an ignition device, the WGV 28v, the electric motor 48m and the air bypass valve 46v.

[0036] Referring back to Fig. 1, the first rotary machine MG1 and the second rotary machine MG2 are rotary electric machines that function as an electric motor (a motor) and a power generator (a generator), and are so-called motor generators. The first rotary machine MG1 and the second rotary machine MG2 can serve as drive power sources for driving the vehicle 10. The first rotary machine MG1 and the second rotary machine MG2 are connected to a battery 54 provided in the vehicle 10 via an inverter 52 provided in the vehicle 10.In the first rotary machine MG1 and the second rotary machine MG2, an MG1 torque Tg [Nm] output from the first rotary machine MG1 and an MG2 torque Tm [Nm] output from the second rotary machine MG2 are controlled by causing the electronic control device 100, which will be described later, to control the inverter 52. For example, in the case of forward rotation, a torque output from a rotary machine is a drive torque at a positive torque, which is an acceleration side, and is a regenerative torque at a negative torque, which is a deceleration side.When the MG1 torque Tg and the MG2 torque Tm output from the first rotating machine MG1 and the second rotating machine MG2 are drive torques, the power output from the first rotating machine MG1 and the second rotating machine MG2 is the travel drive power. The battery 54 transmits and receives electric power to and from the first rotating machine MG1 and the second rotating machine MG2. The battery 54 is a chargeable / dischargeable second battery, such as a lithium-ion battery pack or a nickel-hydride battery pack. The first rotating machine MG1 and the second rotating machine MG2 are provided in a casing 56, which is a non-rotating member attached to the vehicle body. The battery 54 is an example of an "energy storage device" in the claims.

[0037] The power transmission device 14 includes an electrically continuously variable speed unit 58 and a mechanically stepped speed unit 60 arranged in series on a common axis in a housing 56 serving as a non-rotating member mounted on the vehicle body. The continuously variable speed unit 58 is connected to the engine 12 directly or indirectly via a damper or the like, not shown. The stepped speed unit 60 is connected to an output side of the continuously variable speed unit 58. The power transmission device 14 includes a differential gear 68 connected to an output shaft 74, which is an output rotating element of the stepped speed unit 60, and a pair of axles 78 connected to the differential gear.In the power transmission device 14, the power output from the engine 12 or the second rotary machine MG2 is transmitted to the step-change unit 60. The power transmitted to the step-change unit 60 is transmitted to the drive wheels 16 via the differential gear 68 or the like. The step-change unit 60 is provided in a power transmission path PT, which will be described later, between the engine 12 and the drive wheels 16 and between the second rotary machine MG2 and the drive wheels 16. The step-change unit 60 is an example of a "transmission" in the claims.

[0038] The power transmission device 14 having this configuration is appropriately used for a front-engine rear-wheel drive (FR) type vehicle. The continuously variable speed shift unit 58, the step-type speed shift unit 60, or the like is arranged to be substantially symmetrical with respect to the common axis, and a lower half with respect to the axis is not in Fig. 1. The common axis is an axis of a crankshaft of the engine 12, an input shaft 72 connected to the crankshaft, or the like. The intermediate gear member 76, the step gear unit 60, the differential gear 68, and the axes 78 of the power transmission device 14 constitute the power transmission path PT provided between the engine 12 and the drive wheels 16 and between the second rotary machine MG2 and the drive wheels 16.

[0039] The continuously variable transmission unit 58 includes a differential mechanism 80, which is a power splitting mechanism that mechanically splits the power of the engine 12 between the first rotating machine MG1 and the intermediate gear member 76, which is an output rotating member of the continuously variable transmission unit 58. The first rotating machine MG1 is a rotating machine to which the power of the engine 12 is transmitted. The second rotating machine MG2 is connected to the intermediate gear member 76 in a power transmission manner. Since the intermediate gear member 76 is connected to the drive wheels 16 via the step-shifting unit 60, the second rotating machine MG2 is connected to the power transmission path PT in a power transmission manner, and the second rotating machine MG2 is a rotating machine connected to the drive wheels 16 in a power transmission manner.The differential mechanism 80 is a differential mechanism that splits and transmits the power of the engine 12 to the drive wheels 16 and the first rotary machine MG1. The continuously variable transmission unit 58 is an electric continuously variable transmission in which a differential state of the differential mechanism 80 (i.e., a differential state of the continuously variable transmission unit 58) is controlled by controlling the operating state of the first rotary machine MG1, which is connected to the differential mechanism 80 in a power transmission manner. The first rotary machine MG1 is a rotary machine that can control an engine speed Ne. The engine speed Ne is a speed of the engine 12.

[0040] The differential mechanism 80 is a known single pinion planetary gear device including a sun gear S1, a carrier CA1, and a ring gear R1.

[0041] The stepped gear shift unit 60 is a mechanical gear shift mechanism serving as a stepped transmission constituting a part of the power transmission path PT between the intermediate gear member 76 and the drive wheels 16, that is, an automatic transmission constituting a part of the power transmission path PT between the differential mechanism 80 and the drive wheels 16. The intermediate gear member 76 also serves as an input rotational element of the stepped gear shift unit 60. The stepped gear shift unit 60 is, for example, a known automatic planetary transmission including a plurality of planetary gear units such as a first planetary gear unit 82A and a second planetary gear unit 82B, and a plurality of engagement devices such as a clutch C1, a clutch C2, a brake B1, a brake B2, and a one-way clutch F1.In the following description, the clutch C1, the clutch C2, the brake B1 and the brake B2 are simply referred to as engagement devices CB unless they are expressly distinguished from one another.

[0042] Each engagement device CB is a hydraulic friction engagement device constituted by a multi-disk or single-disk clutch or brake pressed by a hydraulic actuator, a band brake tightened by a hydraulic actuator, and the like. In each engagement device CB, an engagement torque, which is a torque capacity of each engagement device CB, is changed according to the adjusted hydraulic pressures output from the solenoid valves SL1 to SL4 in a hydraulic pressure control circuit 84 by causing the electronic control device 100, which will be described later, to control the hydraulic pressure control circuit 84 provided in the vehicle 10. Accordingly, the operating state, such as an engaged state or a disengaged state, of each engagement device CB is switched.

[0043] The first planetary gear unit 82A is a known single-pinion planetary gear unit including a sun gear S2, a carrier CA2, and a ring gear R2. The second planetary gear unit 82B is a known single-pinion planetary gear unit including a sun gear S3, a carrier CA3, and a ring gear R3.

[0044] The differential mechanism 80, the first planetary gear unit 82A, the second planetary gear unit 82B, the engagement devices CB, the one-way clutch F1, the first rotary machine MG1 and the second rotary machine MG2 are connected as shown in Fig. 1. In the differential mechanism 80, the carrier CA1 serves as an input element, the sun gear S1 serves as a reaction element, and the ring gear R1 serves as an output element.

[0045] In the stepped gearshift unit 60, a specific gear stage is formed from a plurality of gearshift stages having different gear ratios γat (= AT input rotational speed Nati [rpm] / AT output rotational speed Nato [rpm]) by switching a combination of the actuation stages of the plurality of engagement devices CB. In the first embodiment, a gear stage formed in the stepped gearshift unit 60 is referred to as an AT gear stage. The AT input rotational speed Nati is an input rotational speed of the stepped gearshift unit 60 and has the same value as the rotational speed of the intermediate gear member 76 and the same value as an MG2 rotational speed Nm [rpm].The AT output speed Nato is a rotational speed of the output shaft 74, which is an output rotating element of the step gear shifting unit 60, and is also an output speed No [rpm] of a compound transmission 62, which is a combined transmission including the continuously variable gear shifting unit 58 and the step gear shifting unit 60.

[0046] Fig. Figure 3 is a diagram showing an example of the optimal engine operating point OPengf in a two-dimensional coordinate system with the engine speed Ne and the engine torque Te as variables. Fig. 3, a maximum efficiency line Leng denotes a group of optimal engine operating points POengf when the engine 12 is operating. An optimal engine operating point OPengf is predetermined as an engine operating point OPeng at which the overall fuel efficiency in the vehicle 10 is best in terms of the charging / discharging efficiency in the battery 54 in addition to the fuel efficiency of the engine 12 alone, for example, when the required engine power Pedem [W] is realized. That is, the engine speed Ne at an optimal engine operating point OPengf is an optimal fuel efficiency speed Neeff at which the engine 12 can output the required engine power Pedem most efficiently.

[0047] The equi-motor energy lines Lpw1, Lpw2, and Lpw3 denote examples where the required motor power Pedem is the motor power Pe1, Pe2, and Pe3, respectively. A point A is a motor operating point OPengA when the motor power Pe1 is realized at the optimal motor operating point OPengf, a point B is a motor operating point OPengB when the motor power Pe2 is reduced at the optimal motor operating point OPengf, and a point C is a motor operating point OPengC when the motor power Pe3 is realized at the optimal motor operating point OPengf. Points A, B, and C are also target values ​​of the motor operating point OPeng, which is expressed by a target motor speed Netgt [rpm] and a target motor torque Tetgt [Nm] (i.e., a target motor operating point OPengtgt). That is, the target engine speed Netgt is a target value of the engine speed Ne and the target engine power Tetgt is a target value of the engine torque Te.The motor power Pe [W] is energy output by the motor 12 and is the traction power output by the motor 12.

[0048] For example, when the target engine operating point OPengtgt changes from point A to point C with an increase in an accelerator opening Θacc [%] (for example, an increase in an accelerator opening based on an increase in a depression amount of an accelerator pedal, not shown, by a driver), the engine operating point OPeng changes on a path that crosses / intersects the maximum efficiency line Leng.

[0049] Even if it is in Fig. 3, the optimal engine operating points OPengf at which the fuel efficiency is highest in the engine 12 with the supercharger SC are stored in advance with a boost pressure Pchg, in addition to the engine speed Ne and the engine torque Te, as variables. The boost pressure Pchg is a target boost pressure Pchgtgt [Pa] when the required engine power Pedm is realized at the optimal engine operating point OPengf.

[0050] Fig. 4 is a diagram showing an example of a power source switching map used for switching control between EV driving and HV driving. Fig. 4, a solid line Lswp is a boundary line between an EV driving range and an HV driving range, where switching between EV driving and HV driving is performed. A range in which a vehicle speed V [km / h] is relatively low and a required driving torque Twdem [Nm] is relatively low (i.e., the required driving power Pwdem [N] is relatively low) is set / defined in advance in the EV driving range. A range in which the vehicle speed V is relatively high and the required driving torque Twdem is relatively high (i.e., the required driving power Pwdem is relatively large) is defined in advance in the HV driving range. When an SOC value SOC [%] of the battery 54, which will be described later, is lower than a predetermined condition value, or when warming up of the engine 12 is necessary, the EV driving range may be selected from Fig. 4 to the HV driving range. The predetermined state value is a predetermined limit / threshold for determining that the state of charge value SOC is a value at which the engine 12 must be forcibly started to charge the battery 54.

[0051] The first rotary machine MG1 and the second rotary machine MG2 are connected to the battery 54 provided in the vehicle 10 via an inverter 52 provided in the vehicle 10. The MG1 torque Tg of the first rotary machine MG1 and the MG2 torque Tm of the second rotary machine MG2 are controlled by causing the electronic control unit 100, which will be described later, to control the inverter 52.

[0052] Fig. 5 is an engagement operation table showing a relationship between a gear shift operation of the step gear shift unit 60 shown in Fig. 1, and a combination of operating states of the engagement devices CB used therein. In the step gear shift unit 60, for example, four AT gear stages for forward movement, including a first AT gear stage (“1st” in Fig. 5) up to a fourth AT gear (“4th” in Fig. 5), designed as a plurality of AT gear stages. The gear ratio γat of the first AT gear stage is the highest and the gear ratio γat becomes lower in a higher AT gear stage. An AT gear stage for the reverse movement (“Rev” in Fig. 5) is formed, for example, by the engagement of the clutch C1 and the engagement of the brake B2. In Fig. 5, "◯" denotes engagement, "Δ" denotes engagement at the time of engine braking or at the time of a slide downshift of the step gearshift unit 60, and a blank denotes disengagement. A slide downshift is, for example, a downshift performed in a deceleration traveling state with an accelerator turned off during the downshift, which is performed due to a decrease in the vehicle speed V during deceleration traveling with the accelerator turned off (the accelerator opening Θacc is 0 or substantially 0). The downshift is synonymous with the downshift, and the upshift is synonymous with the upshift.

[0053] In the step-by-step gearshift unit 60, for example, an AT gear stage established according to the accelerator opening Θacc, which is an operation amount of an accelerator by a driver, is switched according to the vehicle speed V or the like, that is, a plurality of AT gear stages are selectively established by the electronic control device 100, which will be described later. For example, in the gearshift control of the step-by-step gearshift unit 60, so-called clutch-to-clutch gearshift is performed, in which gearshift is performed by switching one of the engagement devices CB, that is, gearshift is performed by switching the engagement devices CB between an engaged state and a disengaged state.

[0054] The vehicle 10 also has a one-way clutch F0 (see Fig. 1). The one-way clutch F0 is a locking mechanism that can fix the carrier CA1 so that it is not rotatable. That is, the one-way clutch F0 is a locking mechanism that can fix an input shaft 72 that is connected to the crankshaft of the engine 12 and that rotates integrally with the carrier CA1 on the housing 56. In the one-way clutch F0, one of two elements that are rotatable relative to each other is integrally connected to the input shaft 72, and the other element is integrally connected to the housing 56. The one-way clutch F0 is inactive in a positive rotation direction, which is a rotation direction at the time of actuation of the engine 12, and automatically engages in a negative rotation direction, which is opposite to that at the time of actuation of the engine 12. When the one-way clutch F0 is inactive, the engine 12 is accordingly rotatable relative to the housing 56.On the other hand, when the one-way clutch F0 is engaged, the motor 12 is not rotatable relative to the housing 56. That is, the motor 12 is fixed to the housing 56 by the engagement of the one-way clutch F0. In this way, the one-way clutch F0 allows rotation in the positive rotation direction of the carrier CA1, which is a rotation direction at the time of actuation of the motor 12, and prevents rotation in the negative rotation direction of the carrier CA1. That is, the one-way clutch F0 is a locking mechanism that can allow rotation in the positive rotation direction of the motor 12 and prevent rotation in the negative rotation direction of the motor 12.

[0055] Fig. 6 is a collinear diagram showing a relative relationship between the rotational speeds of the rotating elements in the continuously variable speed shifting unit 58 and the stepped speed shifting unit 60, which are shown in Fig. 1. In Fig. 6, three vertical lines Y1, Y2, and Y3, corresponding to the three rotating elements of the differential mechanism 80 constituting the continuously variable speed unit 58, are axes each representing, in order from the left, the rotational speed of the sun gear S1 corresponding to a second rotating element RE2, the rotational speed of the carrier CA1 corresponding to a first rotating element RE1, and the rotational speed of the ring gear R1 (i.e., the input rotational speed Nati of the stepped speed unit 60) corresponding to a third rotating element RE3. Four vertical lines Y4, Y5, Y6, and Y7 of the stepped speed unit 60 are axes each representing, in order from the left, the rotational speed of the sun gear S3 corresponding to a fourth rotating element RE4, the rotational speed of the ring gear R2 and the carrier CA3 (i.e.,the rotational speed of the output shaft 74), which are interconnected and correspond to a fifth rotational element RE5, the rotational speed of the carrier CA2 and the ring gear R3, which are interconnected and correspond to a sixth rotational element RE6, and the rotational speed of the sun gear S2, which corresponds to a seventh rotational element RE7. The gaps between the vertical lines Y1, Y2, and Y3 are determined according to a gear ratio ρ1 of the differential mechanism 80 (=number of teeth of the sun gear S1 / number of teeth of the ring gear R1). The gaps between the vertical lines Y4, Y5, Y6, and Y7 are determined according to the gear ratios ρ2 (=number of teeth of the sun gear S2 / number of teeth of the ring gear R2) and ρ3 (=number of teeth of the sun gear S3 / number of teeth of the ring gear R3) of the first planetary gear unit 82A and the second planetary gear unit 182B.

[0056] Referring to the collinear diagram shown in Fig. 6, the engine 12 (see “ENG” in Fig. 6) in the differential mechanism 80 of the continuously variable speed unit 58 is connected to the first rotary element RE1, the first rotary machine MG1 (see “MG1” in Fig. 6) is connected to the second rotation element RE2, the second rotation machine MG2 (see “MG2” in Fig. 6) is connected to the third rotating element RE3, which rotates integrally with the intermediate gear element 76, and the rotation of the engine 12 is transmitted to the stepless gear shifting unit 60 via the intermediate gear element 76. In the stepless gear shifting unit 58, a relationship between the rotational speed of the sun gear S1 and the rotational speed of the ring gear R1 is represented by the straight lines L0e L0m intersecting the vertical line Y2.

[0057] In the stepped gear shift unit 60, the fourth rotating element RE4 is selectively connected to the intermediate gear member 76 via the clutch C1, the fifth rotating element RE5 is connected to the output shaft 74, the sixth rotating element RE6 is selectively connected to the intermediate gear member 76 via the clutch C2 and is selectively connected to the housing 56 via the brake B2, and the seventh rotating element RE7 is selectively connected to the housing 56 via the brake B1. In the stepped gear shift unit 60, the rotational speeds of the "1st", "2nd", "3rd", and "4th" in the output shaft 74 are represented by the straight lines L1, L2, L3, and L4, which intersect the vertical line Y5 through the engagement / disengagement control of the engagement device CB.

[0058] The straight line L0e and the straight lines L1, L2, L3 and L4, which are connected by the solid lines in Fig. 6 indicate relative speeds of the rotating elements at the time of forward traveling in an HV traveling mode with at least the motor 12 as a traveling drive power source. In the HV traveling mode, the motor 12 is a main traveling drive power source, and the first rotating machine MG1 and the second rotating machine MG2 are auxiliary drive power sources for traveling according to necessity. In the differential mechanism 80 in the HV traveling mode, when a reaction torque, which is a negative torque of the first rotating machine MG1 with respect to the motor torque Te input to the carrier CA1, is input to the sun gear S1 at the time of positive rotation, a direct motor-transmitted torque Td [Nm] (= Te / (1 + ρ1) = - 1 / ρ × Tg), which is a positive torque at the time of positive rotation, occurs in the ring gear R1.A combined torque of the direct engine-transmitted torque Td and the MG2 torque Tm is transmitted to the drive wheels 16 as a drive torque Tw in the forward movement direction of the vehicle 10 to the drive wheels 16 via the step gear shift unit 60, in which an AT gear stage is formed from the first AT gear stage to the fourth AT gear stage according to the required drive power Pwdem. At this time, the first rotary machine MG1 serves as a power generator that generates a negative torque at the time of positive rotation. The generated power Wg [W] of the first rotary machine MG1 is charged into the battery 54 or is consumed in the second rotary machine MG2.The second rotary machine MG2 outputs the MG2 torque Tm by using all or part of the generated electric power Wg or the electric power from the battery 54 in addition to the generated electric power Wg.

[0059] The straight line L0m, which is defined by an alternating long and short dashed line in Fig. 6, and the straight lines L1, L2, L3 and L4, which are represented by the solid lines in Fig. 6 indicate relative speeds of the rotating elements at the time of forward traveling in an electric vehicle traveling mode (hereinafter referred to as EV traveling mode) using at least one of the first rotating machine MG1 and the second rotating machine MG2 as a traveling drive power source in a state where the operation of the motor 12 is stopped. Forward traveling in the EV traveling mode includes, for example, a single-drive EV traveling mode in which the motor 12 is not used as a traveling drive power source and only the second rotating machine MG2 is used as a traveling drive power source, and includes, for example, a dual-drive EV traveling mode in which the motor 12 is not used as a traveling drive power source and both the first rotating machine MG1 and the second rotating machine MG2 are used as driving power sources for traveling.The second rotary machine MG2 is an example of a “rotary machine” in the claims.

[0060] In the single-drive EV driving mode, the carrier CA1 does not rotate, and the MG2 torque Tm, which is a positive torque at the time of positive rotation, is input to the ring gear R1. At this time, the first rotating machine MG1 connected to the sun gear S1 enters a no-load state and is idle / inactive at the time of negative rotation.

[0061] In the single-drive EV driving mode, the one-way clutch F0 is released / disengaged and the input shaft 72 is not fixed to the housing 56.

[0062] In the dual-drive EV running mode, the one-way clutch F0 is automatically engaged, so that rotation in the negative rotation direction of the carrier CA1 is prevented when the MG1 torque Tg, which is a negative torque at the time of negative rotation, is input to the sun gear S1 in a state where the carrier CA1 is not rotating. In the state where the carrier CA1 is fixed to be non-rotatable by the engagement of the one-way clutch F0, a reaction torque based on the MG1 torque Tg is input to the ring gear R1. In the dual-drive EV running mode, similar to the single-drive EV running mode, the MG2 torque Tm is input to the ring gear R1.

[0063] At the time of forward travel in the single-drive EV travel mode and the dual-drive EV travel mode, the motor 12 is not driven, the engine speed Ne is 0, and the MG1 torque Tg and / or the MG1 torque Tm is transmitted as a drive torque Tw in the forward travel direction of the vehicle 10 to the drive wheels 16 via the step gear shift unit 60 in which an AT gear stage from the first AT gear stage to the fourth AT gear stage is selected. At the time of forward travel in the single-drive EV travel mode and the dual-drive EV travel mode, the motor 12 is not driven, the MG1 torque Tg is a drive torque which is a negative torque at the time of negative rotation, and the MG2 torque Tm is a drive torque which is a positive torque at the time of positive rotation.

[0064] In the HV driving mode, the target engine operating point OPengtgt is set to achieve the required engine power Pedem for realizing the required drive power Pwdem when the required drive power Pwdem required for the vehicle 10 changes.

[0065] In the HV running mode, the rotational speed of the carrier CA1, i.e., the engine rotational speed Ne, increases or decreases as the rotational speed of the sun gear S1 increases or decreases by controlling the rotational speed of the first rotary machine MG1 with respect to the rotational speed of the ring gear R1, which is restricted to the rotation of the drive wheels 16, forming an AT gear stage in the stepped gear shift unit 60. Accordingly, in the HV running mode, the engine 12 can operate with high efficiency at an engine operating point Peng. The compound transmission 62, which includes the stepped gear shift unit 60 in which an AT gear stage is formed and the continuously variable gear shift unit 58 operating as a continuously variable transmission, can constitute a continuously variable transmission.

[0066] Referring back to Fig. 1, the vehicle 10 includes the electronic control device 100, which serves as a control device for the vehicle 10 in connection with the control of the engine 12, the first rotary machine MG1, the second rotary machine MG2, and the like. The electronic control device 100 is configured to include a so-called microcomputer including, for example, a CPU, a RAM, a ROM, and an input and output interface. The CPU performs various types of control of the vehicle 10 by performing signal processing in connection with a program stored in the ROM in advance, while utilizing a temporary storage function of the RAM. The electronic control device 100 is configured to include a computer for engine control, a computer for rotary machine control, and a computer for hydraulic pressure control according to need.The electronic control device 100 is an example of a “control unit” in the claims.

[0067] The electronic control device 100 is supplied with various signals (e.g., a boost pressure Pchg, a throttle valve opening θth, an engine speed Ne, an output speed No, which is the speed of the output shaft 74 according to a vehicle speed V, an MG1 speed Ng [rpm], which is the speed of the first rotary machine MG1, an MG2 speed Nm, which is the speed of the second rotary machine MG2, a compressor speed Ncmp [rpm], which is the speed of the electric compressor 48c, an accelerator opening θacc, which is an accelerator operation amount indicating the size of the driver's acceleration operation, and a battery temperature THbat [°C], a battery charge / discharge current Ibat [mA], or a battery voltage Vbat [V] of the battery 54) based on detection values ​​from various sensors (e.g., a boost pressure sensor 40, a Throttle valve opening sensor 44,An engine speed sensor 88, an output speed sensor 90, an MG1 speed sensor 92A, an MG2 speed sensor 92B, a compressor speed sensor 94, an accelerator opening sensor 96, and a battery sensor 98) provided in the vehicle 10. The compressor speed Ncmp, which is the speed of the electric compressor 48c in the supercharger SC, is an example of a "compressor speed" in the claims, and an increase rate ΔNcmp, which is an increase rate of the compressor speed Ncmp, is an example of an "increase rate of the compressor speed" in the claims. The increase rate ΔNcmp of the compressor speed is an increase amount per unit time, that is, an increase rate of the compressor speed Ncmp.

[0068] The electronic control device 100 outputs various command signals (for example, an engine control command signal Se for controlling the engine 12, a rotary machine control command signal Smg for controlling the first rotary machine MG1 and the second rotary machine MG2, a hydraulic pressure control command signal SP for controlling the operating states of the engagement devices CB) to various devices (for example, the engine control device 50, the inverter 52, and the hydraulic pressure control circuit 84) provided in the vehicle 10.

[0069] The electronic control device 100 calculates a state of charge value SOC, which is a value indicating the state of charge of the battery 54, based on, for example, the battery charging / discharging current Ibat and the battery voltage Vbat. The electronic control device 100 calculates, based on, for example, the battery temperature THbat and the state of charge value SOC of the battery 54, the charging power Win [W] and the discharging power Wout [W] to define a possible range of the battery power Pbat [W], which is the electric power of the battery 54. The charging power Win and the discharging power Wout are adjusted to mitigate the deterioration of the battery 54.The charging power Win is a possible input power for defining a limitation of the charging power of the battery 54, and the discharging power Wout is a possible output power for defining a limitation of the discharging power Wdis [W] of the battery 54. Accordingly, in view of the deterioration of the battery 54, it is not desirable that the charging electric power of the battery 54 exceeds the charging power Win for a long time or that the discharging electric power Wdis of the battery 54 exceeds the discharging power Wout for a long time.For example, the charging power Win and the discharging power Wout decrease as the battery temperature THbat decreases in a low-temperature region where the battery temperature THbat is lower than in a normal range, and decrease as the battery temperature THbat increases in a high-temperature region where the battery temperature THbat is higher than in the normal range, in order to mitigate the deterioration of the battery 54. For example, the charging power Win decreases as the state of charge value SOC increases in a region where the state of charge value SOC is high. For example, the discharging power Wout decreases as the state of charge value SOC decreases, that is, as a need for charging the battery 54 increases, in a region where the state of charge value SOC is low. The discharging power Wout is an example of the "upper limit of the discharging power" in the claims.

[0070] The electronic control device 100 functionally comprises a determination unit 102, a prediction unit 104 and a control unit 106.

[0071] When the execution of the downshift is determined in the step-shift unit 60, the determination unit 102 determines whether the discharge power Wout is limited. For example, in a relationship including the upshift lines and the downshift lines stored in advance with the vehicle speed V and the accelerator opening θacc as variables (shift diagram or map, not shown), the execution of the downshift is determined when a point indicating a vehicle condition based on the vehicle speed V and the accelerator opening θacc intersects a downshift line. Whether the discharge power Wout is limited is determined, for example, based on whether the discharge power Wout is lower than a predetermined determination power value Woutj.

[0072] Here, a predetermined target gearshift time period Ttrns [ms] is a target value of a predetermined time period (a gearshift time period from the start to the end of the gearshift) required for the progress of the gearshift in view of the balance between the gearshift shock and the gearshift response in execution of a downshift. A predetermined base value ΔNcmp0 is a predetermined standard value of the increase rate ΔNcmp [rpm / ms] of the compressor speed at the time of execution of a downshift. The "downshift execution time period" refers to "a period during which the downshift control is performed" and is, for example, a period during which the so-called clutch-to-clutch gearshift is performed when switching the AT gear stage in the step gearshift unit 60.

[0073] In each type of downshift described later, even if an increase in the engine torque Te is delayed due to a request delay of the boost pressure Pchg, when the increase rate ΔNcmp of the compressor speed at the time of executing a downshift is the predetermined basic value ΔNcmp0 and the discharge power Wout is equal to or greater than the predetermined determination power value Woutj, an assist torque for increasing the AT input speed Nati of the step gearshift unit 60 to a speed corresponding to the AT gear stage after the downshift can be output within the predetermined target gearshift period Ttrns of the second rotary machine MG2. In this way, the predetermined basic value ANcmp0 and the predetermined determination power value Woutj are set in advance by experiment or design.Here, the auxiliary torque is the MG2 torque Tm output from the second rotary machine MG2 and transmitted to the drive wheels 16 to compensate for a shortage of the engine torque Te output from the engine 12, which is a main travel drive power source, and is transmitted to the drive wheels 16.

[0074] When the determination unit 102 determines that the discharge power Wout is limited, the prediction unit 104 predicts whether the necessary discharge power Wnd [W] from the battery 54 required to perform a downshift in the step gear shift unit 60 in the HV travel mode exceeds the discharge power Wout of the battery 54.

[0075] The necessary discharge power Wnd is the discharge power Wdis from the battery 54 (energy consumption in the second rotary machine MG2 or the like) when the increase rate ΔNcmp of the compressor speed is the base value ΔNcmp0, and the gear shift control is performed so that a downshift ends within the predetermined target gear shift period Ttnrs and is a maximum energy value in a period from the start to the end of the downshift. For example, the necessary discharge power Wnd varies depending on the type of combination of an AT gear stage before the shift and an AT gear stage after the shift (a type of downshift) when the downshift is performed.Accordingly, the prediction unit 104 estimates the necessary discharge power Wnd by applying the combination type of the AT gear stages before and after the shift in a downshift that will actually be performed to a predetermined map in which a relationship between the combination type of the AT gear stages before and after the shift in the downshift and the necessary discharge power Wnd is stored in advance.

[0076] When the prediction unit 104 predicts that the required discharge power Wnd exceeds the discharge power Wout, the control unit 106 controls the increase rate ΔNcmp of the compressor speed at the time of downshift execution based on the discharge power Wout and the target boost pressure Pchgtgt. The control unit 106 controls the compressor speed Ncmp and the increase rate ΔNcmp of the compressor speed at the time of downshift execution by controlling, for example, the rotational speed of the electric motor 48m at the time of downshift execution.

[0077] When an increase rate of the engine torque Te is low due to a response delay of the boost pressure Pchg and the auxiliary torque required to increase the AT input speed Nati of the step-shift unit 60 within the predetermined target gearshift period Ttrns is output from the second rotary machine MG2, the necessary discharge power Wnd is more likely to exceed the discharge power Wout when the discharge power Wout is small than when the discharge power Wout is large. To prevent the necessary discharge power Wnd from exceeding the discharge power Wout, it is necessary to reduce the auxiliary torque output from the second rotary machine MG2, and there is a fear that a gearshift response will decrease (there is a fear that a current gearshift period exceeds the predetermined target gearshift period Ttrns).

[0078] Fig. 7 is a graph illustrating a relationship between the discharge power Wout and the compressor speed increase rate ΔNcmp. The control unit 106 performs control such that the compressor speed increase rate ΔNcmp at the time of downshift execution is larger when the discharge power Wout is small than when the discharge power Wout is large.This means that when conditions different from the discharge power Wout are the same (for example, when the target boost pressure Pchgtgt, which will be described later, is constant), control is performed so that the increase rate ΔNcmp of the compressor speed is larger when the discharge power Wout is small than when the discharge power Wout is large, and does not mean that when the conditions different from the discharge power Wout are different, control is performed so that the increase rate ΔNcmp of the compressor speed is larger when the discharge power Wout is small than when the discharge power Wout is large. In this way, the control unit 106 performs control so that the increase rate ΔNcmp of the compressor speed increases at the time of executing a downshift in the step gearshift unit 60 as the discharge power Wout decreases.

[0079] When the target boost pressure Pchgtgt is high, the increase rate of the engine torque Te is more likely to decrease due to a request delay of the boost pressure Pchg, and when the target boost pressure Pchgtgt is low, the amount of assist / auxiliary torque of the second rotary machine MG2 required to increase the AT input speed Nati of the step gearshift unit 60 within the predetermined target gearshift period Ttrns increases. Since a discharge power from the battery 54 to the second rotary machine MG2 increases due to the decrease in the amount of assist torque, the necessary discharge power Wnd increases. When the target boost pressure Pchgtgt is high, the necessary discharge power Wnd is more likely to exceed the discharge power Wout than when the target boost pressure Pchgtgt is low.In order to prevent the necessary discharge power Wnd from exceeding the discharge power Wout, it is necessary to reduce the auxiliary torque output from the second rotary machine MG2, and there is a fear that the gear shift response will deteriorate.

[0080] Fig. 8 is a graph illustrating a relationship between the target boost pressure Pchgtgt and the compressor speed increase rate ΔNcmp. The control unit 106 performs control such that the compressor speed increase rate ΔNcmp at the time of downshift execution is larger when the target boost pressure Pchgtgt is high than when the target boost pressure Pchgtgt is low.This means that when conditions different from the target boost pressure Pchgtgt are the same (for example, when the discharge power Wout is the same), control is performed such that the increase rate ΔNcmp of the compressor speed is necessarily larger when the target boost pressure Pchgtgt is high than when the target boost pressure Pchgtgt is low, and does not mean that when conditions different from the target boost pressure Pchgtgt are different, control is performed such that the increase rate ΔNcmp of the compressor speed is larger when the target boost pressure Pchgtgt is high than when the target boost pressure Pchgtgt is low. In this way, the control unit 106 performs control such that the increase rate ΔNcmp of the compressor speed increases at the time of executing a downshift in the step gearshift unit 60 as the target boost pressure Pchgtgt increases.

[0081] As mentioned above with reference to Fig. 7 and Fig. 8, the control unit 106 controls the increase rate ΔNcmp of the compressor speed at the time of executing a downshift using the discharge power Wout and the target boost pressure Pchgtgt as variables. The control unit 106 controls the increase rate ΔNcmp of the compressor speed in at least a part of a period in which the downshift is executed (a period in which the downshift control is executed) so that the boost pressure Pchg reaches the target boost pressure Pchgtgt within the predetermined target gearshift period Ttrns.

[0082] If the prediction unit 104 predicts that the required discharge power Wnd does not exceed the discharge power Wout, the control unit 106 performs control so that the increase rate ΔNcmp of the compressor speed at the time of downshifting reaches the base value ΔNcmp0. If the determination unit 102 determines that the discharge power Wout is not limited, the control unit 106 further performs control so that the increase rate ΔNcmp of the compressor speed at the time of downshifting reaches the base value ΔNcmp0.

[0083] Fig. Fig. 9 shows an example of a flowchart showing a principal part of a control operation of the electronic control device 100. The flowchart shown in Fig. 9 is performed when it is determined that a downshift is to be performed in the step gear shift unit 60.

[0084] First, in step S10, it is determined whether the discharge power Wout is limited according to the function of the determination unit 102. If the determination result of step S10 is positive, step S20 is performed. If the determination result of step S10 is negative, step S40 is performed.

[0085] In step S20, according to the function of the prediction unit 104, the necessary discharge power Wnd predicted when a downshift is performed is calculated. Then, step S30 is performed.

[0086] In step S30, according to the function of the prediction unit 140, it is predicted whether the required discharge power Wnd is equal to or lower than the discharge power Wout. If the required discharge power Wnd is equal to or lower than the discharge power Wout (that is, if the required discharge power Wnd does not exceed the discharge power Wout), the determination result of step S30 is positive. If the required discharge power Wnd exceeds the discharge power Wout, the determination result of step S30 is negative. If the determination result of step S30 is positive, step S40 is performed. If the determination result of step S30 is negative, step S50 is performed.

[0087] In step S40, according to the function of the control unit 106, the increase rate ΔNcmp of the compressor speed at the time of downshift execution is set to the basic value ANcmp0. Then, step S60 is performed.

[0088] In step S50, according to the function of the control unit 106, the increase rate ΔNcmp of the compressor speed at the time of downshift execution is set based on the discharge power Wout and the target boost pressure Pchgtgt. Accordingly, the increase rate ΔNcmp of the compressor speed set in step S50 has a value greater than the base value ΔNcmp0 set in step S40 and is determined based on the discharge power Wout and the target boost pressure Pchgtgt. Then, step S60 is performed.

[0089] In step S60, according to the function of the control unit 106, the compressor speed Ncmp is controlled so that the increase rate ΔNcmp of the compressor speed reaches the value set in step S40 or S50, and the downshift is performed.

[0090] Fig. Fig. 10 shows an example of a timing chart when the control operation of the electronic control device 100 shown in Fig. 9 is shown.

[0091] In Fig. 10, the horizontal axis represents time t [ms], and the vertical axis represents the accelerator opening θacc, the engine speed Ne, the MG1 speed Ng, the MG2 torque Tm, the MG2 speed Nm, the control hydraulic pressures Pc2 [Pa] and Pb1 [Pa] of the clutch C2 and the brake B1, the boost pressure Pchg, and the discharge power Wdis, in order from the top. The graphs when the control is performed such that the increase rate ΔNcmp of the compressor speed at the time of downshift execution is greater than the basic value ΔNcmp0 according to the first embodiment are represented by thick / bold solid lines, and the graphs when the control is performed such that the increase rate ΔNcmp of the compressor speed at the time of downshift execution reaches the basic value ΔNcmp0 according to a comparison example, are shown by the thick alternating long and short dashed lines.

[0092] First, the graphs (thick solid lines) when the control is performed so that the increase rate ΔNcmp of the compressor speed at the time of downshift execution is larger than the basic value ΔNcmp0 according to the first embodiment shown by the thick solid lines will be described below.

[0093] In a period before time t1, the accelerator opening θacc has an accelerator opening value θacc1 (>0), and the vehicle 10 is traveling in a state where the third AT gear stage ("3rd") is established in the step-by-step gear shift unit 60 based on the accelerator opening value θacc1 and the vehicle speed V. The first rotary machine MG1 serves as a power generator that generates a negative torque at a positive speed value Ng1 (>0), and the electric power Wg generated by the first rotary machine MG1 is consumed in the second rotary machine MG2. Accordingly, the MG2 torque Tm output from the second rotary machine MG2 is a drive torque, and the discharge power Wdis is 0.

[0094] In a period between time t1 and just before time t2 (>t1), the accelerator opening θacc increases from the accelerator opening value θacc1 to an accelerator opening value θacc2 (>θacc1), for example, due to a driver depressing an accelerator pedal. The required drive power Pwdem increases with the increase in the accelerator opening θacc, and the execution of a downshift from the third AT speed stage ("3rd") to the second AT speed stage ("2rd") in the step-shift unit 60 is determined based on a gear shift line, not shown.

[0095] In a period from time t1 to time t2, the engine speed Ne increases with the increase in the accelerator opening θacc, the MG1 speed Ng increases from a speed value Ng1 to a speed value MG2, and the MG2 torque Tm increases from a torque value Tm1 to a torque value Tm2 (>Tm1). With the increase in the engine speed Ne, the boost pressure Pchg also increases by rotating the compressor 18c of the exhaust turbine turbocharger 18. The discharge power Wdis increases to a power value Wdis1 (>0) to increase the MG2 torque Tm.

[0096] The gearshift control is started at time t2, and the gearshift control is terminated at time t4 (>t2). The period from time t2 to time t4 is a period during which a downshift is performed.

[0097] In the period from time t2 to time t4, a control hydraulic pressure Pc2 for the control engagement and control disengagement of the clutch C2 gradually changes from a high state to a low state. On the other hand, in the period from time t2 to time t4, a control hydraulic pressure Pb1 for the control engagement and control disengagement of the brake B1 gradually changes from a low state to a high state. Thus, in the gearshift control period from time t2 to time t4, the disengagement operation of the clutch C2 and the engagement operation of the brake B1 during downshifting from the third AT speed stage to the second AT speed stage are performed by the so-called clutch-to-clutch gearshift.

[0098] When a downshift is performed, control is performed so that the increase rate ΔNcmp of the compressor speed becomes larger than the base value ΔNcmp0. Accordingly, the boost pressure Pchg decreases in a period from time t3 to time t4 (t2 <t3<t4) von einem Druckwert Pchg2 auf einen Druckwert Pchg3 (> Pchg2) increases faster compared to a comparative example described later. The pressure value Pchg3 is a target boost pressure Pchgtgt, which is determined based on the accelerator opening value θacc2.

[0099] In the period from time t2 to time t4, the engine speed Ne increases rapidly to a speed value Ne2 (> Ne1). On the other hand, the MG1 speed Ng increases gradually from a speed value Ng2 to a speed value Ng3 ( <Ng2) ab. In der Zeitspanne vom Zeitpunkt t2 bis zum Zeitpunkt t4 nimmt das MG2-Drehmoment Tm von einem Drehmomentwert Tm2 auf einen Drehmomentwert Tm3 (Tm1<Tm3<Tm2) ab. Die MG2-Drehzahl Nm (=die AT-Eingangsdrehzahl Nati der Stufen-Gangschalteinheit 60) nimmt aufgrund des MG2-Drehmoments Tm von einem Drehzahlwert Nm1 auf einen Drehzahlwert Nm2 (> Nm1).By rapidly increasing the boost pressure Pchg, the engine speed Ne rapidly increases, the AT input speed Nati (=MG2 speed Nm) of the step-shift unit 60 rapidly increases at the time of executing a downshift even when the MG2 torque Tm is equal to or lower than the torque value Tm2 (a torque value Tm4 (>Tm2) in the comparative example), and the discharge power Wdis of the battery 54 becomes equal to or lower than the discharge power Wout. For the purpose of easier understanding of the invention, the discharge power Wdis in the period in which the downshift is performed (the period from time t2 to time t4) is represented as a constant power value Wdis1, but in fact, the discharge power Wdis varies. Even if the discharge power Wdis varies, the necessary discharge power Wnd, which has the maximum value thereof, is lower than the discharge power Wout.

[0100] After time t4, the engine speed Ne is maintained at the speed value Ne2, the MG1 speed Ng is maintained at the speed value Ng3, and the MG2 torque Tm is maintained at the torque value Tm3. The boost pressure Pchg is maintained at the pressure value Pchg3, and the discharge power Wdis is maintained lower than the discharge power Wout. The control hydraulic pressure Pc2 is maintained at a low state, the control hydraulic pressure Pb1 is maintained at a high state, and the gear stage formed in the step gear switching unit 60 is switched to the second AT gear stage.

[0101] The graphs (thick, alternating long and short dashed lines) when control is performed so that the increase rate ΔNcmp of the compressor speed at the time of downshift execution reaches the base value ΔNcmp0 according to a comparative example will be described below. Accordingly, in the graphs according to the comparative example, the description of the same parts as in the graphs according to the first embodiment will be omitted.

[0102] At time t2, the gear shift control is started. Since the control is performed so that the increase rate ΔNcmp of the compressor speed at the time of downshift execution reaches the base value ΔNcmp0 in a period from time t2 to time t5 (>t4), the boost pressure Pchg increases more slowly from the pressure value Pchg2 to the pressure value Pchg3 in a period from time t3 to time t5 compared to the first embodiment.

[0103] In the period from time t2 to time t5, the engine speed Ne1 slowly increases to the speed value Ne2.

[0104] To improve the gearshift response during downshifting according to the comparative example, it is necessary to output a large assist torque from the second rotary machine MG2 so that the AT input rotational speed Nati of the step-type gearshift unit 60 increases rapidly. Similar to the graphs according to the first embodiment, the MG2 torque Tm required for the MG2 rotational speed Nm to increase rapidly so that the AT input rotational speed Nati (=MG2 rotational speed Nm) reaches the rotational speed value at a second time point t4 is represented by a thick alternate long and short dashed line. However, the discharge power Wdis of the battery 54 exceeds the discharge power Wout, as represented by the thick alternate long and short dashed line (and a hatched area), to output the MG2 torque Tm represented by the thick alternate long and short dashed line.Accordingly, a gear shifting period must be extended, so that the gear shifting response deteriorates because the MG2 torque Tm required as the auxiliary torque cannot be output.

[0105] Accordingly, the gearshift control ends later than in the first embodiment, for example, the gearshift control ends at time t5. The time period from time t2 to time t5 is a time period during which the downshift is performed in the comparative example. Thus, the gearshift period (=t5-t2) of a downshift according to the comparative example is longer than the gearshift period (=t4-t2) of the downshift according to the first embodiment, and the gearshift response is inferior.

[0106] The vehicle 10 in which the electronic control device 100 according to the first embodiment is mounted includes the engine 12 with the supercharger SC, the second rotary machine MG2, and the battery 54 that transmits and receives electric power to and from the second rotary machine MG2, uses the power output from the engine 12 and the second rotary machine MG2 as a traveling drive power, and includes the step gear shift unit 60 in the power transmission path PT between the engine 12 and the drive wheels 16 and between the second rotary machine MG2 and the drive wheels 16.

[0107] The control device for a hybrid vehicle according to the first embodiment includes the prediction unit 104 that predicts whether the necessary discharge power Wnd from the battery 54 required to perform a downshift in the step-gear shift unit 60 exceeds the discharge power Wout of the battery 54 when the downshift is performed in the step-gear shift unit 60 in the HV traveling mode, and includes the control unit 106 that controls the compressor rotation speed Ncmp so that the increase rate ΔNcmp of the compressor rotation speed at the time of executing the downshift in the step-gear shift unit 60 increases as the discharge power Wout decreases when the necessary discharge power Wnd is predicted to exceed the discharge power Wout.When a downshift is performed in the step-shift unit 60, as the discharge power Wout of the battery 54 decreases, the increase rate ΔNcmp of the compressor speed increases, a response delay of the boost pressure Pchg decreases, and the increase rate of the engine torque Te increases. Accordingly, it is possible to dampen an amount of auxiliary torque of the second rotary machine MG2 required to increase the AT input speed Nati of the step-shift unit 60, and it is possible to reduce the discharge power Wdis from the battery 54. Consequently, it is possible to prevent the necessary discharge power Wnd from the battery 54, which is required when a downshift is performed in the step-shift unit 60, from exceeding the discharge power Wout of the battery 54, and it is possible to dampen the deterioration of the gearshift response.

[0108] According to the first embodiment, the control unit 106 further controls the compressor speed Ncmp so that the increase rate ΔNcmp of the compressor speed increases as the target boost pressure Pchgtgt increases. As the target boost pressure Pchgtgt increases, the increase rate ΔNcmp of the compressor speed increases, and the boost pressure Pchg increases more rapidly. When a downshift is performed in the step gearshift unit 60, the increase rate ΔNcmp of the compressor speed increases, the increase rate of the boost pressure Pchg becomes more appropriate, and the response delay of the boost pressure Pchg decreases as the target boost pressure Pchgtgt increases. Accordingly, it is possible to prevent the necessary discharge power Wnd from the battery 54, which is required when a downshift is performed in the step gearshift unit 60, from exceeding the discharge power Wout of the battery 54, and it is possible to mitigate the deterioration of the gearshift response.

[0109] According to the first embodiment, the prediction unit 104 estimates the necessary discharge power Wnd using a map in which the relationship between a combination type of the AT gear stages before and after the downshift is performed in the step-shift unit 60 and the necessary discharge power Wnd is stored in advance. By using the map in this way, it is possible to estimate the necessary discharge power Wnd before the downshift is performed.

[0110] According to the first embodiment, the supercharger SC includes the electric supercharger 48, and the control unit 106 controls the compressor speed Ncmp, which is the speed of the electric compressor 48c of the electric supercharger 48. Accordingly, for example, by controlling the speed of the electric motor 48m connected to the electric compressor 48c, the speed of the electric compressor 48c, which is the compressor speed Ncmp of the supercharger SC, is controlled.

[0111] According to the first embodiment, the discharge power Wout is determined based on the battery temperature THbat and the state of charge value SOC. Accordingly, it is possible to mitigate the progress of deterioration of the battery 54 and determine the discharge power Wout according to the need for charging the battery 54.

[0112] According to the first embodiment, it is determined that the discharge power Wout decreases as the degree of deterioration of the battery 54 increases. By determining that the discharge power Wout decreases as the degree of deterioration of the battery 54 increases, it is possible to limit the battery charge / discharge current Ibat, and thus to mitigate the progress of the deterioration of the battery 54.

[0113] According to the first embodiment, the control unit 106 controls the compressor speed Ncmp so that the increase rate ΔNcmp of the compressor speed at the time of performing a downshift in the step-shift unit 60 increases when the discharge power Wout decreases when the discharge power Wout is limited to be lower than the predetermined determination power value Woutj. This is because there is a possibility that the necessary discharge power Wnd will exceed the discharge power Wout when the discharge power Wout is limited.

[0114] Fig. 11 is a functional block diagram schematically illustrating a configuration of a vehicle 210 in which an electronic control unit 200 according to a second embodiment of the invention is mounted, and illustrating a principal part of a control function for various types of control in the vehicle 210. The vehicle 210 is a hybrid vehicle including an engine 12, a rotary machine MG, a power transmission device 214, and drive wheels 16. The elements of the second embodiment that are substantially common to the functions of the first embodiment are denoted by the same reference numerals, and the description thereof will not be repeated.

[0115] An engine torque Te of the engine 12 is controlled by causing the electronic control unit 200, which will be described later, to control an engine control device 50 provided in the vehicle 210.

[0116] The rotary machine MG is an electric rotary machine that has a function of an electric motor and a function of a power generator, and is called a motor generator. The rotary machine MG is connected to the battery 54 provided in the vehicle 210 via an inverter 252 provided in the vehicle 210. In the rotary machine MG, an MG torque Tmg, which is an output torque of the rotary machine MG, is controlled by causing the electronic control unit 200, which will be described later, to control the inverter 252. A generated electric power Wg of the rotary machine MG is charged into the battery 54 or is consumed in an auxiliary machine such as an air conditioner. The rotary machine MG outputs the MG torque Tmg using the power from the battery 54.

[0117] The power transmission device 214 includes a clutch K0 and an automatic transmission 262. An input rotating member of the automatic transmission 262 is connected to the engine 12 via the clutch K0 and is directly connected to the rotating machine MG. The power transmission device 214 includes a differential gear 68 connected to an output side of the automatic transmission 262 and a pair of axles 78 connected to the differential gear 68. In the power transmission device 214, the power output from the engine 12 or the rotating machine MG is transmitted to the automatic transmission 262. The power transmitted to the automatic transmission 262 is transmitted to the drive wheels 16 via the differential gear 68, a pair of axles 78, and the like.The automatic transmission 262 is provided in a power transmission path PT, which will be described later, between the engine 12 and the drive wheels 16 and between the rotary machine MG and the drive wheels 16. The automatic transmission 262 is an example of a "transmission" in the claims.

[0118] The engine 12 and the rotary machine MG are drive power sources for traveling the vehicle 210, which are connected to the drive wheels 16 in a power transmission manner. The automatic transmission 262, the differential gear 68, and the axles 78 in the power transmission device 214 constitute the power transmission path PT provided between the engine 12 and the drive wheels 16, and between the rotary machine MG and the drive wheels 16. The rotary machine MG also functions as a starter that cranks the engine 12 in a state where the clutch K0 is engaged. The rotary machine MG in the second embodiment is an example of a "rotary machine" in the claims.

[0119] The clutch K0 is a hydraulic friction engagement device that connects or cuts off the transmission of power between the engine 12 and the rotating machine MG.

[0120] The automatic transmission 262 may be a stepped transmission, and may be, for example, a stepped planetary gear or a normally toothed parallel-axial stepped transmission. The automatic transmission 262 is controlled to establish one of a plurality of gear stages with different gear ratios by a hydraulic pressure control circuit 284 controlled by the electronic control unit 200, which will be described later. The automatic transmission 262 is an example of a "transmission" in the claims.

[0121] The vehicle 210 can perform EV traveling in which only the rotary machine MG is used as a traveling drive power source using the power from the battery 54 in a state where the clutch K0 is released and the operation of the motor 12 is stopped. The vehicle 210 can perform HV traveling in which the motor 12 is caused to operate in a state where the clutch K0 is engaged and at least the motor 12 is used as a traveling drive power source. That is, in the HV traveling mode, the motor 12 serves as a main traveling drive power source, and the rotary machine MG serves as an auxiliary traveling drive power source according to need.

[0122] The vehicle 210 further includes the electronic control unit 200, which serves as a control device for the vehicle 210 in connection with the control of the engine 12, the rotary machine MG, and the like. The electronic control unit 200 has the same configuration as the control device 100 described above in the first embodiment. The electronic control unit 200 is inputted with various signals that are the same as those inputted to the electronic control device 100. Here, an MG rotation speed Nmg [rpm], which is the rotation speed of the rotary machine MG detected by an MG rotation speed sensor (not shown), is inputted instead of the MG1 rotation speed Ng and the MG2 rotation speed Nm. Various command signals that are the same as those outputted from the electronic control device 100 are outputted from the electronic control unit 200.A rotary machine control command signal Smg is a command signal for controlling the rotary machine MG.

[0123] Similar to the electronic control device 100, the electronic control unit 200 has the same functions as the functions of the determination unit 102, the prediction unit 104, and the control unit 106. Accordingly, similar to the first embodiment, the prediction unit 104 predicts whether the necessary discharge power Wnd of the battery 54 required to perform a downshift in the automatic transmission 262 in the HV traveling mode exceeds the discharge power Wout of the battery 54. When the prediction unit 104 predicts that the necessary discharge power Wnd exceeds the discharge power Wout, the control unit 106 controls the compressor rotation speed Ncmp so that the increase rate ΔNcmp of the compressor rotation speed at the time of executing a downshift in the automatic transmission 262 increases as the discharge power Wout decreases.The control unit 106 controls the compressor speed Ncmp so that the increase rate ΔNcmp of the compressor speed increases as the target boost pressure Pchgtgt increases. The electronic control unit 200 is an example of a "control device" in the claims.

[0124] According to the second embodiment, the same advantages as in the first embodiment are achieved.

[0125] While the first and second embodiments of the invention have been described above in detail with reference to the accompanying drawings, the invention can also be applied to other aspects.

[0126] In the first and second embodiments described above, the supercharger SC includes both the exhaust turbine turbocharger 18 and the electric supercharger 48, but the invention is not limited to this aspect. For example, the supercharger SC may include the exhaust turbine turbocharger 18 and / or the electric supercharger 48. When the supercharger SC includes only the exhaust turbine turbocharger 18, the rotational speed of the compressor 18c in the supercharger SC is an example of a "compressor rotational speed" in the claims, and the control of the increase rate of the compressor rotational speed is performed by adjusting the valve opening of the WGV 28v.

[0127] In the first and second embodiments, the increase rate ΔNcmp of the compressor speed at the time of downshift execution is determined based on two parameters, namely, the discharge power Wout and the target boost pressure Pchgtgt, but the invention is not limited to this aspect. For example, the increase rate ΔNcmp of the compressor speed at the time of downshift execution may be determined based only on the discharge power Wout.

[0128] In the first and second embodiments, the discharge power Wout, which is exemplified as the upper limit of the discharge power, is calculated based on the battery temperature THbat and the state of charge value SOC of the battery 54, but the invention is not limited to this aspect. For example, a deterioration degree of the battery 54 can be estimated from a relationship between the deterioration degree (a progression of the deterioration state) of the battery 54 and a current value of the battery charge / discharge current Ibat and cumulative data of the charge / discharge frequency, which is determined in advance through an experiment, and the discharge power Wout can be calculated based on the estimated deterioration degree.For example, the discharge power Wout decreases to delay the progression of deterioration of the battery 54, and the battery charge / discharge current Ibat is limited to decrease as the deterioration degree of the battery 54 increases. The discharge power Wout can be calculated based on the battery temperature THbat, the state of charge value SC of the battery 54, and the deterioration degree of the battery 54.

[0129] In the first and second embodiments, in the flowchart shown in Fig. 9, step S10 is performed, but it need not be performed. For example, step S10 in the flowchart shown in Fig.9 are omitted, and the processes from step S20 and subsequent steps can be started. That is, regardless of whether the discharge power Wout is limited, (a) the prediction unit 104 can predict whether the necessary discharge power Wnd exceeds the discharge power Wout, and (b) when the prediction unit 104 determines that the necessary discharge power Wnd exceeds the discharge power Wout, the control unit 106 can control the compressor speed Ncmp so that the increase rate ΔNcmp of the compressor speed at the time of executing a downshift in the step gearshift unit 60 increases as the discharge power Wout decreases.

[0130] In the first embodiment and the second embodiment, forward driving is described, but the invention can also be applied to reverse driving.

[0131] In the first embodiment, the one-way clutch F0 is used as a locking mechanism that can fix the carrier CA1 in a non-rotational manner, but the invention is not limited to this aspect. For example, this locking mechanism may be an engagement device such as a gear clutch, a hydraulic friction engagement device such as a clutch or a brake, a dry engagement device, an electromagnetic friction engagement device, or a magnetic powder clutch that selectively connects the input shaft 72 and the housing 56. Alternatively, the vehicle 10 may not have the one-way clutch F0.

Claims

[1] A control device for a hybrid vehicle, the hybrid vehicle (10; 210) comprising an engine (12) with a supercharger (SC) serving as a travel drive power source, a rotary machine (MG2; MG) serving as another travel drive power source, an energy storage device (54) configured to transmit and receive electric power to and from the rotary machine (MG2; MG), and a transmission (60; 262) provided in a power transmission path between the engine (12) and drive wheels (16) and between the rotary machine (MG2; MG) and the drive wheels (16), the control device (100; 200) comprising: a prediction unit (104) configured to predict whether a necessary discharge power (Wnd) from the energy storage device (54) required to perform a downshift in the transmission (60; 262) exceeds an upper limit of the discharge power (Wout) of the energy storage device (54) when the downshift in the transmission (60; 262) is performed in a hybrid vehicle driving mode; and a control unit (106) configured to control a compressor speed (Ncmp) such that an increase rate (ΔNcmp) of the compressor speed (Ncmp) of the supercharger (SC) at the time of downshifting in the transmission (60; 262) increases as the upper limit of the discharge power (Wout) decreases when the necessary discharge power (Wnd) is predicted to exceed the upper limit of the electrical discharge power (Wout). [2] A control device for a hybrid vehicle according to claim 1, wherein the control unit (106) is configured to control the compressor speed (Ncmp) such that the increase rate (ΔNcmp) of the compressor speed (Ncmp) increases as a target boost pressure increases. [3] A control device for a hybrid vehicle according to claim 1 or 2, wherein the prediction unit (104) is configured to estimate the necessary discharge power (Wnd) using a map in which a relationship between a combination type of gear stages before and after the downshift in the transmission (60; 262) and the necessary discharge power (Wnd) is determined in advance. [4] A control device for a hybrid vehicle according to any one of claims 1 to 3, wherein: the charger (SC) comprises at least one electric charger (48); and the compressor speed (Ncmp) of the charger (SC) is a speed of an electric compressor included in the electric charger (48). [5] A control device for a hybrid vehicle according to any one of claims 1 to 4, wherein the upper limit of the discharge power (Wout) is determined based on a temperature and a state of charge value of the energy storage device (54). [6] A control device for a hybrid vehicle according to any one of claims 1 to 5, wherein the upper limit of the discharge power (Wout) is determined to decrease as a degree of deterioration of the energy storage device (54) increases. [7] A control device for a hybrid vehicle according to any one of claims 1 to 6, wherein, when the upper limit of the discharge power (Wout) is limited to be lower than a predetermined determination power value, the control unit (106) is configured to control the compressor speed (Ncmp) so that the rate of increase (ΔNcmp) of the compressor speed (Ncmp) of the supercharger (SC) at the time of downshifting in the transmission (60; 262) increases as the upper limit of the discharge power (Wout) decreases. [8] A control method for a hybrid vehicle (10; 210) comprising an engine (12) with a supercharger (SC) serving as a travel drive power source, a rotary machine (MG2; MG) serving as a travel drive power source, an energy storage device (54) configured to transmit and receive electric power to and from the rotary machine (MG2; MG), and a transmission (60; 262) provided in a power transmission path between the engine (12) and drive wheels (16) and between the rotary machine (MG2; MG) and the drive wheels (16), the control method comprising: Predicting whether a necessary discharge power (Wnd) from the energy storage device (54) required to perform a downshift in the transmission (60; 262) exceeds an upper limit of the discharge power (Wout) of the energy storage device (54) when the downshift in the transmission (60; 262) is performed in a hybrid vehicle driving mode; and Controlling a compressor speed (Ncmp) such that an increase rate (ΔNcmp) of the compressor speed (Ncmp) of the charger (SC) at the time of downshifting in the transmission (60; 262) increases as the upper limit of the discharge power (Wout) decreases when the necessary discharge power (Wnd) is predicted to exceed the upper limit of the electrical discharge power (Wout).

Images