Control device for a vehicle

Abstract

Control device for a vehicle (10; 100) with an internal combustion engine (12), with an automatic transmission (40; 106) which forms part of an energy transmission path between the internal combustion engine (12) and a drive wheel (14), and with a rotary device (MG2) which is coupled to the drive wheel (14) to transmit drive energy, wherein the control device has an electronic control unit (90) which is configured to: a driver assistance control system for driving the vehicle (10, 100) at least by automatically controlling a vehicle speed independently of any driving action by a driver; to perform regenerative braking using the rotary device (MG2) at a time of deceleration while driving with the driver assistance control and to limit downshifting of the automatic transmission (40, 106) when a requested deceleration amount (Grdem) for the vehicle (10, 100) is equal to or less than a predetermined deceleration amount (Grf); and to perform regenerative braking using the rotary device (MG2) at the time of deceleration while driving with the driver assistance control and not to restrict downshifting if the required deceleration amount (Grdem) is higher than the predetermined deceleration amount (Grf), wherein the electronic control unit (90) is configured to perform a shift depending on whether downshifting is to be limited on the basis of the requested deceleration amount (Grdem), if a second requested deceleration amount for the vehicle (10, 100) associated with an operation by the driver is not included in the requested deceleration amount (Grdem) during driving with the driver assistance control, the required deceleration amount (Grdem) is a deceleration amount (Gr) achievable by regenerative braking and by engine braking using the friction of the internal combustion engine (12); and the electronic control unit (90) is configured to set the requested deceleration amount (Grdem) equal to or lower than the predetermined deceleration amount (Grf) when the deceleration amount (Gr) is increased by a wheel brake in a state where the requested deceleration amount (Grdem) is higher than the predetermined deceleration amount (Grf) at the time of deceleration during driving with the driver assistance control.

Description

BACKGROUND OF THE INVENTION 1. Field of the invention

[0001] The present invention relates to a control device for a vehicle with an internal combustion engine, an automatic transmission and a rotary device. 2. Description of the state of the art

[0002] A control device for a vehicle with an internal combustion engine, an automatic transmission, and a rotary device is generally known. The automatic transmission forms part of an energy transmission path between the internal combustion engine and the drive wheels. The rotary device is coupled to the drive wheels to transmit drive energy. This control device corresponds, for example, to a vehicle control device described in JP 2018-62247A. JP 2018-62247A discloses that the automatic transmission downshifts when necessary by means of regenerative braking performed by the rotary device, when there is a requirement to decelerate the vehicle.

[0003] Furthermore, JP H10-73161A discloses a drive control device for a hybrid vehicle with an engine and an automatic transmission between the engine and the drive wheels. It includes a brake assist control system to support regenerative braking. During regenerative braking, gear shift prevention can occur, regardless of at least the vehicle speed. If it is determined that the actual deceleration is insufficient compared to the target deceleration, the automatic transmission downshifts. If the actual deceleration is not insufficient (i.e., if the actual deceleration is equal to or greater than the target deceleration), the shift state of the automatic transmission is not affected.

[0004] DE 10 2008 024 622 A1 refers to a hybrid vehicle that uses a hydraulic brake.

[0005] DE 10 2013 104 315 A1, in turn, relates to the control of the regenerative braking torque in a hybrid vehicle powertrain during a transmission ratio change that occurs during regenerative braking. A brake control unit is provided that divides the total wheel braking torque between (i) a powertrain brake torque signal (representing the torque quantity to be achieved through regenerative braking) and (ii) a friction brake torque signal (representing the torque quantity to be achieved through friction braking). SUMMARY OF THE INVENTION

[0006] When decelerating, the vehicle can also be slowed by engine braking, which is generated by friction. Using engine braking during deceleration can increase the deceleration by downshifting the automatic transmission. This makes it easy to achieve the required deceleration. However, downshifting can increase noise and vibration (NV) due to the increased engine speed. NV is a general term for noise and vibration generated in the vehicle. When driving with driver assistance systems that control the vehicle independently of driver input, the driver may perceive NV more easily than when driving with manual controls based on driver input. Therefore, increased NV can impair drivability.When the required deceleration value increases and decreases, it can lead to jerky shifting, i.e., repeated downshifting and upshifting. While driving with the driver assistance control system, the driver may perceive changes in engine speed or gear shift jolts more easily than when driving with manual controls. Therefore, jerky shifting can negatively impact driving performance.

[0007] The present invention was made under the circumstances described above and is based on the objective of providing a control device for a vehicle in which a decrease in drivability can be suppressed, whereby a required amount of deceleration is achieved at the time of deceleration during driving with the driver assistance control.

[0008] One aspect of the present invention relates to a control device for a vehicle with an internal combustion engine, with an automatic transmission which forms part of an energy transmission path between the internal combustion engine and a drive wheel, and with a rotary device which is coupled to the drive wheel for the transmission of drive energy.The control device includes an electronic control unit configured to: perform a driver assistance control to drive the vehicle, at least by automatically controlling a vehicle speed independently of any driving input from the driver; perform regenerative braking using the rotary device at a time of deceleration while driving with the driver assistance control and to limit downshifting of the automatic transmission when a required deceleration amount for the vehicle is equal to or less than a predetermined deceleration amount; and to perform regenerative braking using the rotary device at a time of deceleration while driving with the driver assistance control and not to limit downshifting when the required deceleration amount is greater than the predetermined deceleration amount.The electronic control unit is configured to perform a shift depending on whether downshifting is to be limited based on the required deceleration amount, if a second required deceleration amount for the vehicle, resulting from driver input, is not included in the required deceleration amount while driving with the driver assistance control system. The required deceleration amount is the amount achievable through regenerative braking and engine braking using the friction of the combustion engine.The electronic control unit is also configured to set the required deceleration amount equal to or lower than the predetermined deceleration amount if the deceleration amount is increased by a wheel brake in a state where the required deceleration amount is higher than the predetermined deceleration amount at the time of deceleration while driving with the driver assistance control.

[0009] As described above, regenerative braking is executed during deceleration while driving with the assistance control system. If the required deceleration amount is equal to or less than the predetermined deceleration amount, downshifting of the automatic transmission is limited. If the required deceleration amount is greater than the predetermined deceleration amount, downshifting is not limited. In this way, the vehicle's deceleration is controlled. During gentle deceleration, an increase in engine speed and a rise in engine power are suppressed, thus preventing jerky gear changes. During heavy deceleration, a large deceleration amount is achieved easily through downshifting.Thus, the decrease in drivability can be suppressed by achieving the required amount of deceleration at the time of deceleration while driving with the driver assistance control.

[0010] Based on the above aspect, the predetermined deceleration amount can be a predetermined maximum value of a deceleration amount achievable through regenerative braking.

[0011] According to the aspect described above, the predetermined deceleration amount is the maximum value achievable through regenerative braking. During gentle deceleration, the required deceleration amount can be achieved through regenerative braking, although downshifting is limited.

[0012] Based on the above aspect, the electronic control unit can be configured to restrict downshifting by prohibiting / forbidding downshifting.

[0013] As described above, downshifting is restricted by prohibiting / prohibiting it. During gentle deceleration, the increase in NV (Non-V) along with the rise in engine speed is reliably suppressed, and jerky shifting is reliably prevented.

[0014] According to the above aspect, the electronic control unit can be configured to: generate a deceleration amount through regenerative braking without using the engine brake, using the friction of the internal combustion engine, when the required deceleration amount is equal to or lower than the predetermined deceleration amount; and generate the deceleration amount through the engine brake and regenerative braking when the required deceleration amount is higher than the predetermined deceleration amount.

[0015] According to the aspect described above, if the required deceleration is equal to or less than the predetermined deceleration, the required deceleration is generated by regenerative braking without using engine braking. During gentle deceleration, the required deceleration can be achieved even though downshifting is prohibited. If the required deceleration is greater than the predetermined deceleration, the required deceleration is generated by engine braking and regenerative braking. During heavy deceleration, the required deceleration can be achieved by increasing the friction of the internal combustion engine through downshifting.

[0016] According to the above aspect, the electronic control unit is configured to perform a shift depending on whether downshifting is limited based on the required deceleration amount, if a second required deceleration amount for the vehicle associated with an actuation by the driver during driving with the driver assistance control is not included in the required deceleration amount.

[0017] If, according to the aspect described above, the second required deceleration amount, which accompanies driver input while driving with the driver assistance control, is not included in the required deceleration amount, the shifting will be performed depending on whether downshifting is to be limited based on the required deceleration amount. Thus, the increase in NV and jerky shifting are easily suppressed if no driver input of the brakes or any other input to reduce vehicle speed is made during deceleration.

[0018] In the above context, the required deceleration amount is the amount of deceleration to be achieved through regenerative braking and engine braking, utilizing the friction of the internal combustion engine. The electronic control unit is configured so that the required deceleration amount is equal to or lower than the predetermined deceleration amount when the deceleration is increased by a wheel brake in a state where the required deceleration amount is higher than the predetermined deceleration amount at the time of deceleration while driving with the driver assistance control engaged.

[0019] In accordance with the aspect described above, when increasing the deceleration amount by the wheel brakes in a situation where the required deceleration amount to be achieved through regenerative braking and engine braking is higher than the predetermined deceleration amount at the time of deceleration while driving with the driver assistance control system, the required deceleration amount is set to be equal to or lower than the predetermined deceleration amount. This prevents the automatic transmission from downshifting and generates a large deceleration amount by the wheel brakes with good responsiveness.

[0020] According to the above aspect, the electronic control unit can be configured to control the vehicle, at least by automatically controlling a vehicle speed based on information about the vehicle's surroundings.

[0021] According to the aspect described above, the driver assistance control system is a drive control system for driving the vehicle by automatically controlling the vehicle speed based on information about the vehicle's surroundings. This ensures that the required deceleration is achieved appropriately and that the vehicle speed is controlled appropriately at the time of deceleration while driving with the driver assistance control system engaged. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Features, advantages and technical and industrial significance of exemplary embodiments of the invention are described below with reference to the accompanying drawings, in which the same reference numerals denote the same elements, and wherein: Fig. 1 a diagram to describe a schematic structure of a vehicle to which the present invention is applied, and to describe a main part of the control functions and a control system for different types of control of the vehicle; Fig. 2. An operating table to describe the relationships between the gear-shifting processes of a mechanical stepped transmission unit. Fig. 1 and the operating combinations of intervention devices for use in gear shifting operations; Fig. 3 is a nomogram that shows a relative relationship between the rotational speeds of the rotating elements of a continuously variable electric transmission unit and the mechanical stepped transmission unit. Fig. 1 represents; Fig. 4 is a diagram that shows examples of and a relationship between an automatic transmission (AT) gear shift diagram for use in the gear shift control of the mechanical step-through transmission unit from Fig. 1 and a driving mode switching diagram for use in driving mode switching control; Fig. 5 a flowchart to describe a main part of a control process of an electronic control unit and to describe a control process to suppress a decrease in drivability when a required deceleration is reached at the time of deceleration during driving with the driver assistance control; Fig. 6 is a diagram that represents an example of a time diagram in a case where the flowchart of Fig. The control process shown in point 5 is executed and a gentle deceleration is performed; Fig. 7 is a diagram that represents an example of a time diagram for the case where the flowchart of Fig. 5. The control process shown is executed and a strong braking action is performed; Fig. 8 is a diagram that shows an example of a time diagram in a case where the flowchart of Fig. The control process shown in section 5 is executed and the wheel brakes are applied during heavy braking; and Fig. 9 is a diagram describing a schematic structure of a vehicle to which the present invention is applied, and describing an embodiment that differs from the embodiment in relation to the vehicle in Fig. 1 distinguishes. DETAILED DESCRIPTION OF THE EXECUTION FORMS

[0023] In embodiments of the present invention, a transmission ratio of an automatic transmission is defined as "rotational speed of the input-side rotating element / rotational speed of the output-side rotating element". A high side of the transmission ratio is a side with high vehicle speed where the transmission ratio is low. A low side of the transmission ratio is a side with low vehicle speed where the transmission ratio is high. For example, a transmission ratio on the lowest side is a transmission ratio on the side with the lowest vehicle speed and is a maximum transmission ratio.

[0024] The embodiments of the present invention are described in detail below with reference to the drawings. First embodiment

[0025] Fig. Figure 1 is a diagram describing the overall structure of a vehicle 10 to which the present invention is applied, and also describes a main part of a control system for various types of control of the vehicle 10. Fig. The vehicle 10 comprises an internal combustion engine 12, a first rotary device MG1, and a second rotary device MG2. The vehicle 10 also comprises drive wheels 14 and a power transmission device 16, which is provided on a power transmission path between the internal combustion engine 12 and the drive wheels 14.

[0026] The internal combustion engine 12 is a power source designed to generate motive force. The internal combustion engine 12 is a gasoline internal combustion engine, a diesel internal combustion engine, or another commonly known internal combustion engine. An engine torque Te, which is an output torque of the internal combustion engine 12, is controlled by an internal combustion engine control device 50, which includes a throttle actuator, a fuel injection device, and an ignition device, provided in the vehicle 10 by an electronic control unit 90 described later.

[0027] Both the first rotary device MG1 and the second rotary device MG2 are so-called motor-generators, which are rotating electrical machines with the functions of an electric motor (motor) and an electric generator (generator). The first rotary device MG1 and the second rotary device MG2 are connected to a battery 54 in the vehicle 10 via an inverter 52. An MG1 torque Tg, which is an output torque of the first rotary device MG1, and an MG2 torque Tm, which is an output torque of the second rotary device MG2, are controlled by the inverter 52 via the electronic control unit 90 described later.Regarding the output torque of the rotary device, for example, a positive torque on an acceleration side is a power torque, and a negative torque on a deceleration side is a regenerative torque during positive rotation in the same direction of rotation as during operation of the internal combustion engine 12. The battery 54 is an energy storage device configured for the exchange of electrical energy with the first rotary device MG1 and the second rotary device MG2. The first rotary device MG1 and the second rotary device MG2 are provided in a housing 18, which is a non-rotating element attached to a vehicle body.

[0028] The power transmission device 16 comprises an electric continuously variable transmission unit 20 and a mechanical stepped transmission unit 22, which are arranged in series on a common central shaft in the housing 18. The electric continuously variable transmission unit 20 is coupled directly or indirectly to the internal combustion engine 12 via a damper (not shown) or the like. The mechanical stepped transmission unit 22 is coupled to an output side of the electric continuously variable transmission unit 20. The power transmission device 16 further comprises a differential 26 and a pair of axles 28. The differential 26 is coupled to an output shaft 24, which is a rotary output element of the mechanical stepped transmission unit 22. The axles 28 are coupled to the differential 26. The axles 28 are coupled to the drive wheels 14. The combined assembly is referred to below as the "continuously variable transmission unit 20".The mechanical stepped gear unit 22 is hereinafter referred to as "stepped gear unit 22". The continuously variable transmission unit 20, the stepped gear unit 22, and other devices are arranged essentially symmetrically about the common central axis. In . Fig. 1. A lower half below the axis center point is omitted. The common axis center point serves, for example, as the axis center point of a crankshaft of the internal combustion engine 12 and a clutch shaft 30, which is an input rotary element of the continuously variable transmission unit 20 coupled to the crankshaft.

[0029] The continuously variable transmission unit 20 comprises the first rotary device MG1 and a differential mechanism / gearbox 34, which serves as an energy distribution device configured to mechanically divide the drive energy of the internal combustion engine 12 between the first rotary device MG1 and an intermediate gear element 32, which is an output rotary element of the continuously variable transmission unit 20. The second rotary device MG2 is coupled to the intermediate gear element 32 to transmit the drive energy. The continuously variable transmission unit 20 is an electric continuously variable transmission in which a differential state of the differential mechanism 34 is controlled by controlling an operating state of the first rotary device MG1. The continuously variable transmission unit 20 operates as an electric continuously variable transmission configured to change a transmission ratio γ0 (= engine speed Ne / MG2 speed Nm).The engine speed Ne is the speed of the internal combustion engine 12 and assumes the same value as the input speed of the continuously variable transmission unit 20, i.e., the speed of the clutch shaft 30. The MG2 speed Nm is the speed of the second rotary device MG2 and assumes the same value as the output speed of the continuously variable transmission unit 20, i.e., the speed of the intermediate gear element 32. The first rotary device MG1 can control the engine speed Ne and corresponds to a differential rotary device. The control of the operating state of the first rotary device MG1 is an operating control for the first rotary device MG1.

[0030] The differential mechanism 34 is a single-pinion planetary gear and comprises a sun gear S0, a carrier CA0, and a ring gear R0. The internal combustion engine 12 is coupled to the carrier CA0 via the clutch shaft 30 to transmit the drive energy. The first rotary device MG1 is coupled to the sun gear S0 to transmit the drive energy. The second rotary device MG2 is coupled to the ring gear R0 to transmit the drive energy. In the differential mechanism 34, the carrier CA0 acts as the input element, the sun gear S0 acts as the reactive element, and the ring gear R0 acts as the output element.

[0031] The stepped transmission unit 22 is a mechanical gearshift mechanism that serves as a stepped transmission and forms part of a power transmission path between the intermediate transmission element 32 and the drive wheels 14, i.e., the continuously variable transmission unit 20 and the drive wheels 14. The intermediate transmission element 32 also functions as the input rotary element of the stepped transmission unit 22. The second rotary device MG2 is rotationally fixed to the intermediate transmission element 32. The second rotary device MG2 acts as a drive source, designed to generate a driving force, and corresponds to a drive drive rotary device. The internal combustion engine 12 is coupled to an input side of the continuously variable transmission unit 20. Thus, the stepped transmission unit 22 is an automatic transmission that forms part of a power transmission path between the drive source (internal combustion engine 12 and second rotary device MG2) and the drive wheels 14.The second rotary device MG2 is coupled to the energy transmission path between the internal combustion engine 12 and the drive wheels 14 to transmit the drive energy. That is, the second rotary device MG2 is coupled to the drive wheels 14 via the step-through transmission unit 22 to transmit the drive energy. Examples of the step-through transmission unit 22 include a well-known planetary automatic transmission comprising several sets of planetary gears, namely a first planetary gear 36 and a second planetary gear 38, as well as several engagement devices, namely a clutch C1, a clutch C2, a brake B1, and a brake B2, including a one-way clutch F1. Unless otherwise specified, the clutch C1, clutch C2, brake B1, and brake B2 are hereby simply referred to as "engagement devices CB".

[0032] Each engagement device CB is a hydraulic friction engagement device with a multi-disc or single-disc clutch or brake actuated by a hydraulic actuator, or with a band brake applied by the hydraulic actuator. A control state, such as an engaged or non-engaged / released state, i.e., an operating state of each engagement device CB, is switched by changing a torque capacity using controlled engagement pressures of the engagement device CB, which are output by solenoid valves SL1 to SL4 of a hydraulic control circuit 56 in the vehicle 10.

[0033] In the stepped gear unit 22, rotary elements of the first planetary gear 36 and the second planetary gear 38 are coupled directly or indirectly, via the engagement devices CB and the one-way clutch F1, either to each other or partially to the intermediate gear element 32, the housing 18, or the output shaft 24. The rotary elements of the first planetary gear 36 are a sun gear S1, a carrier CA1, and a ring gear R1. The rotary elements of the second planetary gear 38 are a sun gear S2, a carrier CA2, and a ring gear R2.

[0034] The stepped gear unit 22 is a stepped gear unit configured to select any gear from a plurality of gears that differ in a gear ratio (= AT input speed Ni / output speed No) by, for example, engaging predetermined engagement devices from the plurality of engagement devices. That is, the stepped gear unit 22 shifts the gear, i.e., it performs a gear change by engaging one of the engagement devices. In this embodiment, the gear selected by the stepped gear unit 22 is referred to as the "AT gear." The AT input speed Ni is an input speed of the stepped gear unit 22, i.e., a speed of the intermediate gear element 32, and has the same value as the MG2 speed Nm. The AT input speed Ni can be represented by the MG2 speed Nm.The output speed No is an output speed of the stepped transmission unit 22, i.e., a speed of the output shaft 24. The output speed No is also an output speed of a complex transmission 40, which is a complete transmission comprising a combination of the continuously variable transmission unit 20 and the stepped transmission unit 22. The complex transmission 40 is an automatic transmission that forms part of the power transmission path between the internal combustion engine 12 and the drive wheels 14. The engine speed Ne is also an input speed of the complex transmission 40.

[0035] As in an intervention activation table in Fig. As shown in Figure 2, the stepped transmission unit 22, for example, provides four forward automatic transmission gear stages, including a first automatic transmission gear stage (“1st” in Fig. 2) to a fourth AT gear stage (“4th” in Fig. 2) are, as a multitude of AT gear ratios. The gear ratio γat is highest in the first AT gear ratio and decreases with each subsequent AT gear ratio. For example, an AT reverse gear (“Rev” in Fig. 2) by engaging the clutch C1 and the brake B2. This means that the first automatic transmission gear is set, for example, for reversing. The engagement table in Fig. Section 2 is a summary of the relationships between the AT gear stages and the operating states of the engagement devices. That is, the engagement operating table in Fig. Section 2 is a summary of the relationships between the AT gear stages and the predetermined engagement devices to be engaged at each AT gear stage. Fig. 2 stands for “O” for intervention, “Δ” for intervention at the time of engine braking or downshifting of the step transmission unit 22 and an empty field stands for non-intervention / release.

[0036] In the stepped transmission unit 22, the automatic transmission gear stages to be set are selected depending on, for example, the driver's accelerator pedal input or the vehicle speed V; that is, the automatic transmission gear stages are selectively set by the electronic control unit 90 described later. In the gear shift control of the stepped transmission unit 22, the gear change is carried out, for example, by changing the engagement state of any intervention device CB, i.e., by switching between the engagement and non-engagement of any intervention device CB. This gear shifting is a so-called clutch-to-clutch shift.

[0037] The vehicle 10 further comprises a mechanical oil pump (MOP) 58 and an electric oil pump (not shown). The MOP 58 is coupled to the clutch shaft 30 and rotates with the rotation of the internal combustion engine 12 to pump / drain hydraulic oil OIL for use in the power transmission device 16. For example, the electric oil pump (not shown) is driven to drain the hydraulic oil OIL when the internal combustion engine 12 is stationary, i.e., when the MOP 58 is not driven. The hydraulic oil OIL pumped by the MOP 58 or the electric oil pump (not shown) is supplied to the hydraulic control circuit 56. The operating state of each engagement device CB is switched by the engagement pressures, which are controlled by the hydraulic control circuit 56 based on the hydraulic oil OIL.

[0038] Fig. Figure 3 is a nomogram or Kutzbach diagram illustrating a relative relationship between the rotational speeds of the rotating elements of the continuously variable transmission unit 20 and the stepped transmission unit 22. Fig. 3 are three vertical lines Y1, Y2, and Y3, corresponding to the three rotational elements of the differential mechanism 34 of the continuously variable transmission unit 20. Starting from the left, the g-axis represents the rotational speed of the sun gear S0, corresponding to a second rotational element RE2; the e-axis represents the rotational speed of the carrier CA0, corresponding to a first rotational element RE1; and the m-axis represents the rotational speed of the ring gear R0, corresponding to a third rotational element RE3 (i.e., the input speed of the stepped transmission unit 22). The four vertical lines Y4, Y5, Y6, and Y7 of the stepped transmission unit 22 are axes representing, starting from the left, the rotational speed of the sun gear S2, corresponding to a fourth rotational element RE4; the rotational speed of the ring gear R1 and the carrier CA2, which are coupled together, corresponding to a fifth rotational element RE5 (i.e.,The rotational speed of the output shaft 24), the rotational speed of the carrier CA1 and the ring gear R2, which are coupled together and correspond to a sixth rotational element RE6, and the rotational speed of the sun gear S1, which corresponds to a seventh rotational element RE7, are represented. The distances between the vertical lines Y1, Y2, and Y3 are determined based on a gear ratio ρ0 of the differential mechanism 34. The distances between the vertical lines Y4, Y5, Y6, and Y7 are set based on a gear ratio ρ1 of the first planetary gear 36 and a gear ratio ρ2 of the second planetary gear 38. In the relationship between the vertical axes of the nomogram, if a distance between the sun gear and the carrier corresponds to "1", a distance between the carrier and the ring gear corresponds to a gear ratio ρ of the planetary gear (= number of teeth of the sun gear / number of teeth of the ring gear).

[0039] In the representation using the nomogram of Fig. 3 The differential mechanism 34 of the continuously variable transmission unit 20 transmits the rotation of the internal combustion engine 12 via the intermediate gear element 32 to the stepped transmission unit 22, by means of the internal combustion engine 12 (see “ENG” in Fig. 3) with the first rotary element RE1, the first rotary device MG1 (see “MG1” in Fig. 3) with the second rotary element RE2 and the second rotary device MG2 (see “MG2” in Fig. 3) are coupled to the third rotating element RE3, which rotates together with the intermediate gear element 32. In the continuously variable transmission unit 20, the relationships between the rotational speed of the sun gear S0 and the rotational speed of the ring gear R0 are each represented by straight lines L0e, L0m and L0R, which intersect the vertical line Y2.

[0040] In the stepped gear unit 22, the fourth rotary element RE4 is selectively coupled to the intermediate gear element 32 via the clutch C1, the fifth rotary element RE5 is coupled to the output shaft 24, the sixth rotary element RE6 is selectively coupled to the intermediate gear element 32 via the clutch C2 and to the housing 18 via the brake B2, and the seventh rotary element RE7 is selectively coupled to the housing 18 via the brake B1. In the stepped gear unit 22, the rotational speeds of the output shaft 24 at "1st", "2nd", "3rd", "4th", and "Rev" are each represented by straight lines L1, L2, L3, L4, and LR, which intersect the vertical line Y5 through the engagement / non-engagement control at the engagement devices CB.

[0041] In Fig. Figure 3 shows that the continuous lines L0e, L1, L2, L3, and L4 represent the relative velocities of the rotating elements during forward travel in a hybrid vehicle (HV) driving mode, in which the vehicle can perform hybrid driving (= HV driving) using at least the internal combustion engine 12 as a drive source. HV driving is internal combustion engine driving in which at least the drive force of the internal combustion engine 12 is utilized. In HV driving mode, when the MG1 torque Tg, which is a negative reaction torque of the first rotating device MG1, is applied to the sun gear S0 against the positive engine torque Te, which is applied to the carrier CA0 in the differential mechanism 34, a direct engine torque Td (= Te / (1 + ρ0) = - (1 / ρ0) x Tg) is generated in the ring gear R0, which is a positive torque in the positive rotation.In response to a requested driving force Frdem, a torque combined from the direct engine torque Td and the MG2 torque Tm is transmitted as drive torque in a forward direction of the vehicle 10 via the stepped transmission unit 22, which shifts any automatic transmission gear from the first to the fourth gear stage, to the drive wheels 14. The first rotating device MG1 acts as an electric generator when producing a negative torque in the positive direction of rotation. The electrical energy Wg generated by the first rotating device MG1 is charged into the battery 54 or consumed by the second rotating device MG2. The second rotating device MG2 outputs the MG2 torque Tm by using all or part of the generated electrical energy Wg, or by using electrical energy from the battery 54 in addition to the generated electrical energy Wg.

[0042] In Fig. Figure 3 shows the long-short dashed straight line L0m and the solid straight lines L1, L2, L3, and L4 representing the relative velocities of the rotating elements during forward travel in an electric vehicle (EV) driving mode. In this mode, the vehicle can perform an electric motor drive (EV drive) using the second rotating device MG2 as the drive source, while the operation of the internal combustion engine 12 is suspended / stopped. The EV drive is an electric motor drive in which only the driving force of the second rotating device MG2 is used. During the EV drive while traveling forward in the EV driving mode, the rotation of the carrier CA0 is zero, and the MG2 torque Tm, which is a positive torque in the positive direction of rotation, is applied to the ring gear R0. At this point, the first rotating device MG1, which is coupled to the sun gear S0, is in an unloaded state due to negative rotation.This means that during forward travel in EV driving mode, the combustion engine 12 is not driven, the engine speed Ne is zero, and the MG2 torque Tm is transmitted as drive torque in the forward direction of the vehicle 10 via the step-through transmission unit 22, which shifts any automatic transmission gear from the first to the fourth gear, to the drive wheels 14. The MG2 torque Tm is a positive power torque in the positive direction of rotation.

[0043] In Fig. Figure 3 shows that the dashed lines L0R and LR represent the relative rotational speeds of the rotating elements during reverse travel in EV mode. During reverse travel in EV mode, the MG2 torque Tm, which is a negative torque in the negative direction of rotation, is applied to the ring gear R0 and transmitted as drive torque in a reverse direction of the vehicle 10 via the step-through transmission unit 22, which engages the first automatic transmission gear stage, to the drive wheels 14. In the vehicle 10, reverse travel can be initiated by the electronic control unit 90, described later, which causes the second rotating device MG2 to output the reverse MG2 torque Tm with a positive / negative sign opposite to the forward MG2 torque Tm during forward travel in a state in which, for example, the first automatic transmission gear stage, which is the forward automatic transmission gear stage on the low side, is engaged from the multitude of automatic transmission gear stages.The MG2 torque Tm is a negative power torque in the negative direction of rotation. Even in HV driving mode, the negative rotation of the second rotary device MG2 can be executed, as indicated by the straight line L0R. Thus, reverse driving can be performed similarly to EV driving mode.

[0044] Vehicle 10 is a hybrid vehicle with the internal combustion engine 12 and the second rotary device MG2 as its drive sources. In the energy transmission device 16, the drive energy output by the internal combustion engine 12 or by the second rotary device MG2 is transferred to the step-through transmission unit 22, and from the step-through transmission unit 22, via the differential gear 26 and the like, to the drive wheels 14. Thus, the energy transmission device 16 transmits the drive force from the drive source (internal combustion engine 12 or second rotary device MG2) to the drive wheels 14. Drive energy has the same meaning as torque or force, unless otherwise specified.

[0045] Referring back to Fig. 1 The vehicle 10 has the electronic control unit 90, which serves as a control device including a control device for the vehicle 10, which is connected to the control of, for example, the internal combustion engine 12, the continuously variable transmission unit 20 and the stepped transmission unit 22. Fig. Figure 1 is a diagram illustrating the input / output system of the electronic control unit 90 and is also a functional block diagram describing a major part of the control functions of the electronic control unit 90. The electronic control unit 90 comprises a so-called microcomputer with a central processing unit (CPU), random access memory (RAM), read-only memory (ROM), and an input / output interface. The CPU performs various types of control of the vehicle 10 by processing signals based on programs pre-stored in the ROM and utilizing a temporary storage function of the RAM. Depending on requirements, the electronic control unit 90 includes internal combustion engine control, rotary device control, and hydraulic control computers.

[0046] The electronic control unit 90 receives various signals (e.g., the engine speed Ne, the output speed No according to the vehicle speed V, an MG1 speed Ng of the first rotating device MG1, the MG2 speed Nm with the same value as the AT input speed Ni, an accelerator pedal actuation amount Θacc indicating the magnitude of a driver's acceleration actuation, a throttle valve opening degree Θth indicating the opening degree of an electronic throttle valve, a brake-ON signal Bon indicating a state in which the driver is depressing a brake pedal to use wheel brakes, a brake actuation amount Bra indicating the magnitude of a driver's actuation to depress the brake pedal, a steering angle Θsw and a steering direction Dsw of a steering wheel in the vehicle 10, a steering-ON signal SWon indicating a state in which the driver is gripping the steering wheel, a driver state signal Drv indicating the driver's state,a longitudinal acceleration Gx and a lateral acceleration Gy of the vehicle 10, a yaw rate Ryaw, which is a rotational angular velocity about a vertical axis of the vehicle 10, a battery temperature THbat, a battery charge / discharge current Ibat and a battery voltage Vbat of the battery 54, a hydraulic oil temperature THoil of the hydraulic oil OIL, vehicle environment information Iard, position information Ivp, a communication signal Scom, navigation information Inavi, a driver assistance setting signal Sset, which indicates the driver's settings for the driver assistance control CTs, such as autonomous driving control or speed control (cruise control), and an actuation position POSsh of a gearshift lever in the vehicle 10) based on detection values ​​from various sensors in the vehicle 10 (for example, an engine speed sensor 60, an output speed sensor 62, an MG1 speed sensor 64, an MG2 speed sensor 66,an accelerator pedal actuation amount sensor 68, a throttle valve opening degree sensor 70, a brake pedal sensor 71, a steering sensor 72, a driver condition sensor 73, a G-sensor 74, a yaw rate sensor 76, a battery sensor 78, an oil temperature sensor 79, a vehicle environment information sensor 80, a vehicle position sensor 81, an external network communication antenna 82, a navigation system 83, a driver assistance setting switch unit 84 and a shift position sensor 85).

[0047] The driver's accelerator pedal actuation amount is an accelerator pedal actuation amount that is an actuation amount of an acceleration device actuation element, such as an accelerator pedal, and is an output amount requested by the driver for the vehicle 10. The throttle valve opening degree Θth or similar can be used as the driver's requested output amount, as can the accelerator pedal actuation amount Θacc.

[0048] The driver condition sensor 73 includes at least one camera configured to capture the driver's facial expression or pupils, and a biological information sensor configured to capture the driver's biological information and the driver's condition, such as the driver's gaze direction, face direction, eyeball or face movement, and heart rate.

[0049] The vehicle environment information sensor 80 comprises at least one lidar sensor, a radar, and an on-board camera, and acquires the vehicle environment information Iard directly from the surroundings of the vehicle 10. The vehicle environment information Iard relates to a roadway and objects around the vehicle. The lidar sensor corresponds, for example, to a plurality of lidar sensors configured to detect objects in front of, beside, and behind the vehicle 10, or to a single lidar sensor configured to detect objects around the vehicle 10. The lidar sensor outputs object information relating to the detected objects as vehicle environment information Iard.For example, the radar corresponds to a variety of radar devices configured to detect objects in front of, near the front of, and near the rear of the vehicle 10, and outputs object information about the detected objects as vehicle environment information (Iard). The object information from the lidar sensor or radar includes distances and directions of the detected objects from the vehicle 10. The onboard camera, for example, is a monocular or stereo camera configured to image areas in front of or behind the vehicle 10, and outputs the image information as vehicle environment information (Iard). The image information includes information about lanes of a roadway, road signs, parking spaces and other vehicles, pedestrians, or obstacles on the roadway.

[0050] The vehicle position sensor 81 has a GPS (Global Positioning System) antenna. The position information Ivp includes information about the driver's vehicle position, showing the current position of the vehicle 10 on the ground or on a map, based, for example, on a GPS signal (trajectory signal) from a GPS satellite.

[0051] The Navigation System 83 is a well-known navigation system with a display and a speaker. The Navigation System 83 determines the driver's vehicle's position using pre-stored map data based on the position information Ivp. The Navigation System 83 displays the driver's vehicle's position on a map shown on the display. When a destination is entered, the Navigation System 83 calculates a route from the starting point to the destination and uses the display and speaker to provide the driver with information such as route guidance. The navigation information Ivp includes map information, such as road information and device information, based on the map data pre-stored in the Navigation System 83. Road information includes details about road types, such as city streets, suburban roads, mountain roads, and highways.Highways, junctions and intersections, road gradients, and speed limits. Information about facilities includes details about the type, location, and names of places such as supermarkets, shops, restaurants, parking lots, parks, vehicle repair shops, apartments, and rest areas along highways / expressways. A rest area is a location with facilities such as a parking lot, a restaurant, and a gas station on a highway / expressway. The road information or similar data in the Inavi navigation information can also serve as vehicle environment information.

[0052] The driver assistance control switch unit 84 has an autonomous driving selector switch for autonomous driving control, a vehicle speed switch for vehicle speed control, a switch for setting a vehicle speed during vehicle speed control / for cruise control, a switch for setting a vehicle-to-vehicle distance to a vehicle ahead during vehicle speed control, and a lane keeping control switch, in which the vehicle drives while maintaining a designated lane.

[0053] The Scom communication signal comprises road traffic information sent to and received from a central unit, which may be an external device such as a road traffic information communication system, and / or vehicle-to-vehicle communication information sent directly to and received by other vehicles in the vicinity of vehicle 10 without intervention from the central unit. The road traffic information includes details about traffic jams, accidents, construction sites, time restrictions, and parking areas on roads. The vehicle-to-vehicle communication information includes vehicle information, travel information, and traffic environment information. The vehicle information includes details about the vehicle type, such as a car, truck, or motorcycle.Driving / travel information includes vehicle speed (V), position, brake pedal activity, turn signal flashing, and hazard warning light flashing. Traffic environment information includes details of traffic jams and roadworks.

[0054] The electronic control unit 90 outputs various command signals (e.g., an internal combustion engine control command signal Se for controlling the internal combustion engine 12, a rotary device control command signal Smg for controlling the first rotary device MG1 and the second rotary device MG2, a hydraulic control command signal Sat for controlling the operating states of the intervention devices CB, a communication signal Scom, a brake control command signal Sbra for controlling a braking torque Tb of the wheel brakes, a steering control command signal Sste for controlling the steering of the wheels (especially the front wheels), and an information message control command signal Sinf for transmitting an alarm or notification to the driver) to devices in the vehicle 10 (e.g.,to the combustion engine control device 50, the inverter 52, the hydraulic control circuit 56, the external network communication antenna 82, a wheel brake device 86, a steering device 88 and an information signaling device 89).

[0055] The wheel brake device 86 uses the braking torque Tb of the wheel brakes for the wheels. The braking torque Tb is a negative torque on one side of the brakes resulting from a drive torque Tr. The wheel brake device 86 supplies hydraulic brake pressure to the wheel cylinders of the wheel brakes, for example, in response to the driver's application of the brake pedal. In the wheel brake device 86, the wheel cylinders are normally supplied with master cylinder hydraulic pressure as brake hydraulic pressure. This pressure is generated by a master brake cylinder and has a magnitude corresponding to the amount of brake application Bra. In the wheel brake device 86, for example, when controlling the anti-lock braking system (ABS), traction control, automatic vehicle speed control, or autonomous driving control, the wheel cylinders are supplied with a brake hydraulic pressure required for the respective type of control to generate the braking torque Tb of the wheel brakes.The wheels are the drive wheels 14 and driven wheels (not shown).

[0056] For example, the steering device 88 uses a support / assistance torque for a steering system of the vehicle 10, based on the vehicle speed V, the steering angle Θsw, the steering direction Dsw, and the yaw rate Ryaw. For example, during autonomous driving control, the steering device 88 uses a torque to control the steering of the front wheels for the steering system of the vehicle 10.

[0057] For example, the information signaling device 89 issues a warning or notification to the driver in the event of a malfunction relating to the operation of the vehicle 10 or in the event of a decrease in functions relating to the operation of the vehicle 10. The information signaling device 89 includes a display device, such as a monitor, a display, or an alarm light, and / or an audible output device, such as a speaker or a beeper. The display device provides a visual warning or notification to the driver. The audible output device provides an audible warning or notification to the driver.

[0058] In order to implement different types of control of the vehicle 10, the electronic control unit 90 has AT gear shift control means, i.e. an AT gear shift control device 92, hybrid control means, i.e. a hybrid control device 94, deceleration control means, i.e. a deceleration control device 96, and driving control means, i.e. a driving control device 98.

[0059] The AT gearshift control device 92 executes a gearshift determination for the stepped transmission unit 22, for example by selecting a gear in Fig. The AT gear shift diagram shown in Figure 4 is used, which depicts a predetermined relationship, i.e., a relationship determined through experimentation or design and stored in advance. The AT gear shift control device 92 outputs the hydraulic control command signal Sat to the hydraulic control circuit 56, as required to execute the gear shift control for the step-through transmission unit 22.

[0060] In Fig. Figure 4 of the AT gear shift diagram shows a predetermined relationship in which, for example, a variety of types of predetermined gear shift lines SH are provided for determining the gear shift for the stepped transmission unit 22 on a two-dimensional coordinate system with the vehicle speed V and the required drive force Frdem as variables. Instead of the vehicle speed V, the output speed No can be used, for example. Instead of the required drive force Frdem, a required drive torque Trdem, the accelerator pedal actuation amount Θacc, or the throttle valve opening degree Θth can be used, for example. The gear shift lines SH include solid upshift lines SHua, SHub, and SHuc for determining the upshift and dashed downshift lines SHda, SHdb, and SHdc for determining the downshift.

[0061] The hybrid control device 94 has a function as an internal combustion engine control device, i.e., an internal combustion engine control device configured to control the operation of the internal combustion engine 12, and a function as a rotary device control device, i.e., a rotary device control device configured to control the operation of the first rotary device MG1 and the second rotary device MG2 via the inverter 52. These control functions enable, for example, hybrid drive control using the internal combustion engine 12, the first rotary device MG1, and the second rotary device MG2.

[0062] For example, the hybrid control device 94 calculates the required drive force Frdem of the drive wheels 14 as the required drive amount by applying the accelerator pedal actuation amount Θacc and the vehicle speed V to a characteristic map for the required drive amount, which has a predetermined relationship. In addition to the required drive force Frdem [N], the required drive torque Trdem [Nm] of the drive wheels 14, the required drive power Prdem [W] of the drive wheels 14, or a required AT output torque of the output shaft 24 can also be used as the required drive amount.For example, the hybrid control device 94 outputs the combustion engine control command signal Se to control the combustion engine 12 and the rotary device control command signal Smg to control the first rotary device MG1 and the second rotary device MG2 in order to achieve the required drive power Prdem based on the required drive torque Trdem and the vehicle speed V, taking into account the rechargeable electrical energy Win and the dischargeable electrical energy Wout of the battery 54. The combustion engine control command signal Se, for example, is a setpoint / command value of the combustion engine power Pe of the combustion engine 12, which delivers an engine torque Te at an engine speed Ne at the setpoint / command output time.For example, the rotary device control command signal Smg is a setpoint / command value of the electrical energy Wg to be generated by the first rotary device MG1, which delivers an MG1 torque Tg as a reaction torque of the motor torque Te at an MG1 speed Ng at the setpoint / command output time, and is a setpoint / command value of an energy consumption Wm of the second rotary device MG2, which delivers an MG2 torque Tm at an MG2 speed Nm at the setpoint / command output time.

[0063] The rechargeable electrical energy Win of battery 54 is an input electrical energy that defines a limit to the input electrical energy of battery 54. The dischargeable electrical energy Wout of battery 54 is an output electrical energy that defines a limit to the electrical output energy of battery 54. The rechargeable electrical energy Win and the dischargeable electrical energy Wout of battery 54 are calculated, for example, by the electronic control unit 90 based on the battery temperature THbat and a state of charge (SOC) [%], which corresponds to the charge level of battery 54. The state of charge (SOC) of battery 54 indicates the state of charge of battery 54 and is calculated by the electronic control unit 90, for example, based on the battery charge / discharge current Ibat and the battery voltage Vbat.

[0064] For example, if the continuously variable transmission unit 20 operates as a continuously variable transmission and the complex transmission 40 also functions as a continuously variable transmission, the hybrid control device 94 changes the transmission ratio γ0 of the continuously variable transmission unit 20 by performing the continuously variable gear shift control for the continuously variable transmission unit 20 in such a way that the electrical energy Wg to be generated by the first rotary device MG1 is controlled and the internal combustion engine 12 is controlled so that it has an engine speed Ne and an engine torque Te that can achieve an internal combustion engine power Pe to obtain the required drive power Prdem, taking into account, for example, an optimal internal combustion engine operating point. As a result of this control, a transmission ratio γt (= Ne / No) of the complex transmission 40 is controlled when used as a continuously variable transmission.The optimal combustion engine operating point is, for example, set as a combustion engine operating point at which the overall fuel efficiency of the vehicle 10 is highest, taking into account the fuel efficiency of the combustion engine 12 and the charging / discharging efficiency of the battery 54, when achieving the required combustion engine power Pedem. The combustion engine operating point is an operating point of the combustion engine 12, which is represented by the engine speed Ne and the engine torque Te. Thus, in the energy transmission device 16, the entire complex transmission 40 with the continuously variable transmission unit 20 and the stepped transmission unit 22, which are arranged in series, can function as a continuously variable transmission, with the stepped transmission unit 22 setting the automatic transmission gear stages and the continuously variable transmission unit 20 operating as a continuously variable transmission.

[0065] The continuously variable transmission unit 20 can perform gear changes similar to a stepped transmission. Therefore, the complex transmission 40 of the power transmission device 16 can perform gear changes similar to a stepped transmission through the stepped transmission unit 22, which sets the automatic transmission gear ratios, and through the continuously variable transmission unit 20, which performs gear changes similar to a stepped transmission. That is, the stepped transmission unit 22 and the continuously variable transmission unit 20 of the complex transmission 40 can be controlled to selectively use a variety of gear ratios that differ in the gear ratio γt, which is a ratio of the engine speed Ne to the output speed No. In this embodiment, the gear ratios used by the complex transmission 40 are referred to as "simulated gear ratios".The transmission ratio γt is an overall transmission ratio set by the continuously variable transmission unit 20 and by the stepped transmission unit 22, which are arranged in series / one behind the other, and is a value obtained by multiplying the transmission ratio γ0 of the continuously variable transmission unit 20 with the transmission ratio γat of the stepped transmission unit 22 (γt = γ0 x γat).

[0066] For example, the simulated gear ratios are assigned such that one or more types of simulated gear ratios for each automatic transmission (AT) gear ratio of the stepped transmission unit 22 are formed by a combination of each AT gear ratio of the stepped transmission unit 22 and one or more types of the transmission ratio γ0 of the continuously variable transmission unit 20. The simulated gear ratios are preset, for example, such that for the first AT gear ratio, a first simulated gear ratio up to a third simulated gear ratio is used; for the second AT gear ratio, a fourth simulated gear ratio up to a sixth simulated gear ratio is used; for the third AT gear ratio, a seventh simulated gear ratio up to a ninth simulated gear ratio is used; and for the fourth AT gear ratio, a tenth simulated gear ratio is used.In the complex transmission 40, various simulated gear stages are used for a specific automatic transmission (AT) gear stage by controlling the continuously variable transmission (CVT) unit 20 to maintain an engine speed Ne that achieves a predetermined gear ratio γt with respect to the output speed No. In the complex transmission 40, the simulated gear stages are engaged by controlling the CVT unit 20 synchronously with the shifting of the AT gear stages.

[0067] For example, if the continuously variable transmission unit 20 performs a gear shift like the stepped transmission, and the entire complex transmission 40 performs a gear shift like the stepped transmission, the hybrid control device 94 performs a gear shift determination for the complex transmission 40, for example, by using a simulated gear shift diagram showing a predetermined relationship, and performs a gear shift control for the continuously variable transmission unit 20 to selectively use a variety of simulated gears in conjunction with a gear shift control for the automatic transmission gears of the stepped transmission unit 22 by the automatic transmission gear shift control device 92. The simulated gears can be used by controlling the engine speed Ne as a function of the output speed No using the first rotary device MG1 to maintain the respective gear ratios γt.The gear ratio γt of each simulated gear stage need not be an essentially constant value over the entire range of the output speed No, but can be varied within a predetermined range or, for example, limited by upper and lower speed limits for each segment. Thus, the hybrid control device 94 can perform gear shift control to change the engine speed Ne as in the case of a stepped gear transmission. For example, the simulated stepped gear shift control, which causes the complex transmission 40 to perform gear shifting like a stepped transmission, can be prioritized over the continuously variable transmission control, which causes the entire complex transmission 40 to operate as a continuously variable transmission, only if the driver selects a sporty driving mode or other performance-oriented driving modes, or if the required drive torque Tr is relatively high.The simulated step-by-step gear shift can generally be executed unless there is a predetermined execution restriction.

[0068] Depending on the driving conditions, the hybrid control device 94 selectively sets the EV driving mode or the HV driving mode as the driving mode. For example, the hybrid control device 94 uses a Fig. 4 shown driving mode switching schedule, which shows a predetermined relationship to use the EV driving mode in an EV driving range where the required drive power Prdem is relatively small, and to use the HV driving mode in an HV driving range where the required drive power Prdem is relatively large.

[0069] In Fig. Figure 4 shows the driving mode switching schedule with a predetermined relationship, in which, for example, a boundary line between the HV driving range and the EV driving range is defined for switching between the HV and EV driving modes in the two-dimensional coordinate system, which has the vehicle speed V and the required drive force Frdem as variables. The boundary line is, for example, a predetermined long-short dashed driving range switching line CF for determining the switch between EV and HV driving. Since the change of driving modes is accompanied by a change of the drive source, the driving range switching line CF is also a drive source switching line. Fig. Figure 4 shows the driving mode switching diagram together with the AT gear shift diagram for the sake of simplicity.

[0070] Even if the required drive power Prdem is within the EV driving range, the hybrid control device 94 initiates the HV driving mode if, for example, the state of charge (SOC) of the battery 54 is lower than a predetermined combustion engine start threshold or if the combustion engine 12 needs to be warmed up. The combustion engine start threshold is a predetermined threshold for determining whether the state of charge (SOC) requires charging the battery 54 by forcibly starting the combustion engine 12.

[0071] When the HV driving mode is used while the operation of the internal combustion engine 12 is stopped, the hybrid control device 94 executes the internal combustion engine start control to start the internal combustion engine 12. To start the internal combustion engine 12, the hybrid control device 94, for example, increases the engine speed Ne using the first rotary device MG1 and ignites the internal combustion engine 12 when the engine speed Ne is equal to or higher than a predetermined ignition speed. That is, the hybrid control device 94 starts the internal combustion engine 12 by cranking the internal combustion engine 12 using the first rotary device MG1.

[0072] The braking control device 96 calculates a required deceleration Grdem as the required deceleration amount, for example, based on the driver's accelerator pedal input (e.g., based on the accelerator pedal input amount θacc or a rate of decrease of the accelerator pedal input amount θacc), the vehicle speed V, the gradient of a slope, and the driver's braking input to use the wheel brakes (e.g., the braking input amount Bra or a rate of increase of the braking input amount Bra), and sets a required braking torque Tbdem to achieve the required deceleration Grdem using a predetermined relationship. For example, the deceleration amount can be represented by a deceleration Gr, a braking force, or a braking torque. In addition to the required deceleration Grdem, a required braking force, a required braking torque, or the like can also be used as the required deceleration amount.In this embodiment, the deceleration Gr is used as the amount of deceleration and the required deceleration Grdem as the required amount of deceleration. When the vehicle 10 decelerates, the braking control device 96 generates the braking torque Tb of the vehicle 10 to obtain the required braking torque Tbdem. The side on which the deceleration Gr is high is a side on which the braking torque Tb is small, that is, the absolute value of the braking torque Tb is large.

[0073] The braking torque Tb of vehicle 10 is generated, for example, by a regenerative braking torque Tbr, a wheel braking torque Tbw, or an engine braking torque Tbe. The regenerative braking torque Tbr, for instance, is a braking torque Tb obtained by braking exerted by regenerative control using the second rotary device MG2, i.e., by regenerative braking of the second rotary device MG2. In regenerative control with the second rotary device MG2, the second rotary device MG2 is set in rotation by a drive torque supplied by the drive wheels 14 to operate as an electric generator and charges the battery 54 with the generated electrical energy via the inverter 52. The wheel braking torque Tbw is a braking torque Tb obtained by the wheel brakes using the wheel brake device 86.The engine braking torque Tbe is a braking torque Tb applied by the engine brake through friction of the internal combustion engine 12.

[0074] The braking torque Tb of vehicle 10 is generated, for example, primarily using the regenerative braking torque Tbr, with the aim of improving energy efficiency. The braking control device 96 issues a command to the hybrid control device 94 to execute regenerative control using the second rotary device MG2 in order to obtain the regenerative torque required for the regenerative braking torque Tbr. During the rotation of the internal combustion engine 12, the engine brake is used, thus generating the engine braking torque Tbe, based on the engine speed Ne, as the braking torque Tb of vehicle 10. The regenerative braking torque Tbr and the engine braking torque Tbe are braking torques Tb generated by the drive sources, i.e., drive source braking torques Tbp.

[0075] For example, if the absolute value of the required braking torque Tbdem is relatively small, the braking control device 96 achieves the required braking torque Tbdem by using only the regenerative braking torque Tbr. If, for example, the absolute value of the required braking torque Tbdem is relatively large, the braking control device 96 achieves the required braking torque Tbdem by adding the wheel braking torque Tbw to the regenerative braking torque Tbr.

[0076] Immediately before the vehicle 10 comes to a stop, for example, the braking control device 96 achieves the required braking torque Tbdem by replacing the regenerative braking torque Tbr with the wheel braking torque Tbw. The braking control device 96 outputs the brake control command signal Sbra to the wheel brake device 86 to obtain the wheel braking torque Tbw required to achieve the required braking torque Tbdem.

[0077] During the rotation of the internal combustion engine 12, the required braking torque Tbdem is achieved, for example, by adding the engine braking torque Tbe to the regenerative braking torque Tbr. When the engine braking torque Tbe is applied, its absolute value increases because the simulated gear stage of the complex transmission 40 is at a lower vehicle speed, for example, under the condition that the vehicle speed V remains constant. When the engine braking torque Tbe is applied, the braking control device 96 issues a command to downshift the complex transmission 40 to the automatic transmission gearshift control device 92 and the hybrid control device 94, for example, based on the vehicle speed V, the conditions of a driving route, such as a gradient, and the required braking torque Tbdem. For example, simulated gear stages of the complex transmission 40 are preset that are prohibited / forbidden when braking the vehicle 10.The braking control device 96 issues the command to downshift the complex transmission 40 by sequentially switching on prohibition flags for the simulated gear stages of the complex transmission 40 starting from the high vehicle speed side.

[0078] The driving control device 98 can, as a driving control in the vehicle 10, execute the manual driving control CTm to initiate the driving of the vehicle 10 based on driving inputs from the driver, and can execute the driving assistance control CTs to drive the vehicle 10 independently of the driver's driving inputs. With manual driving control CTm, the vehicle 10 is driven by manual driving inputs from the driver. Manual driving is a driving style in which the vehicle 10 is normally driven by driving inputs from the driver, such as accelerator pedal operation, brake pedal operation, and steering input. With driving assistance control CTs, the vehicle 10 is driven, for example, by a driving assistance system to automatically support the driving inputs. Driving assistance is a driving method in which the vehicle 10 is driven by automatic control of speed or the like by the electronic control unit 90 based on, for example,Information and signals from various sensors allow the vehicle to drive independently of the driver's input and intentions. Examples of automatic speed control include acceleration, deceleration, and steady driving through the application of the accelerator and brakes.

[0079] Examples of driver assistance control systems (CTs) include autonomous driving control, where the vehicle 10 drives autonomously to automatically set a target driving condition based on map information and a destination input from the driver, and to automatically perform speed control and steering based on the target driving condition. The driver assistance control system (CTs) can be any driving control for driving the vehicle 10, at least through automatic speed control. Examples of driver assistance control systems (CTs) can include, in addition to autonomous driving control, automatic vehicle speed control, where the driver performs part of the driving operation, such as steering.Examples of automatic vehicle speed control include the well-known adaptive cruise control (ACC), which acts as a vehicle speed control system to regulate the drive torque Tr, including the braking torque Tb, in order to ensure that the vehicle speed V follows a target vehicle speed Vtgt set by the driver or that a vehicle-to-vehicle distance to a vehicle ahead, also set by the driver, is maintained. Another example of automatic vehicle speed control is the well-known adjustable speed limiter (ASL), which regulates a drive force Fr to prevent the vehicle speed V from exceeding the target vehicle speed Vtgt set by the driver.This means that the CTs driver assistance control is a driving control system for guiding the vehicle 10 at least by automatically controlling the vehicle speed V on the basis of, for example, the vehicle environment information Iard.

[0080] If driving using the driver assistance system is not selected because the autonomous driving selector switch or the driving speed switch of the driver assistance system setting switch unit 84 is switched off, the driving control device 98 performs manual driving control CTm by using a manual driving mode. For example, the driving control device 98 performs manual driving control CTm by issuing commands to the AT gearshift control device 92, the hybrid control device 94, and the braking control device 96 to control the step-through transmission unit 22, the internal combustion engine 12, the first rotary device MG1, the second rotary device MG2, and the wheel brake device 86 to control the speed in response to a driver operation.

[0081] When autonomous driving control is selected because the driver activates the autonomous driving selector switch of the driver assistance setting switch unit 84, the driving control device 98 executes autonomous driving control by using an autonomous driving mode. In particular, the driving control device 98 automatically sets a target driving condition based on a destination input entered by the driver, the driver's vehicle position information obtained from the position information Ivp, map information obtained from the navigation information Inavi, and various types of information about driving routes obtained from the vehicle environment information Iard.The driving control device 98 performs autonomous driving control by issuing commands to the AT gearshift control device 92, the hybrid control device 94 and the braking control device 96 to control the step transmission unit 22, the internal combustion engine 12, the first rotary device MG1, the second rotary device MG2 and the wheel brake device 86, and by issuing the steering control command signal Sste to the steering device 88 to control the steering of the front wheels in order to automatically perform speed control and steering based on the set target driving condition.

[0082] When adaptive cruise control (ACC) is selected because the driver operates the cruise control switch of the driver assistance setting switch unit 84, the drive control unit 98 executes the ACC by using an ACC mode. Specifically, the drive control unit 98 issues commands to the automatic transmission gearshift control unit 92, the hybrid control unit 94, and the braking control unit 96 to control the step-through transmission unit 22, the internal combustion engine 12, the first rotary device MG1, the second rotary device MG2, and the wheel brake device 86 to automatically control the speed based on the target vehicle speed Vtgt and the vehicle distance to the vehicle ahead, which are set by the driver.The hybrid control device 94 or the braking control device 96 sets a required ACC torque Taccdem, which is a required torque in ACC based on the target vehicle speed Vtgt and the vehicle distance to the vehicle ahead, which are set by the driver. The hybrid control device 94, the braking control device 96, and the like automatically control the speed to achieve the required ACC torque Taccdem. During braking, when the required ACC torque Taccdem has a negative value, the required ACC torque Taccdem serves as the required braking torque Tbdem.

[0083] While driving with the CTs driving assistance control, the driver may perceive NV, a change in engine speed Ne, or a gearshift jolt more easily than when driving with the manual CTm driving control. If the engine speed Ne is increased by downshifting the complex transmission 40 to achieve the required deceleration Grdem at the time of deceleration while driving with the CTs driving assistance control, NV may increase and drivability may decrease. If, due to an increase and decrease in the required deceleration Grdem at the time of deceleration while driving with the CTs driving assistance control, jerky shifting occurs, i.e., repeated downshifting and upshifting of the complex transmission 40, a change in engine speed or a gearshift jolt may occur, and drivability may decrease.

[0084] The braking control device 96 performs regenerative braking using the second rotary device MG2 during deceleration while driving with the CTs driver assistance control system. If the required deceleration Grdem of the vehicle 10 is equal to or less than a predetermined deceleration Grf, which is a predetermined deceleration amount, the braking control device 96 restricts the downshifting of the complex transmission 40. If the required deceleration Grdem is greater than the predetermined deceleration Grf, the braking control device 96 does not restrict the downshifting of the complex transmission 40. In this way, the braking control device 96 controls the deceleration Gr of the vehicle 10.

[0085] For example, the predetermined deceleration Grf is a predetermined maximum value of the deceleration Gr achievable by regenerative braking using the second rotary device MG2. For example, the predetermined deceleration Grf is also a predetermined maximum value of the (achievable) deceleration Gr that can be achieved when the actuation position / operating position POSsh of the shift lever is a D actuation position. That is, the predetermined deceleration Grf is a deceleration Gr that can be achieved, for example, by the required braking torque Tbdem when an accelerator pedal actuation amount θacc from zero is applied to the required drive amount plan. In this embodiment, the braking torque Tb for achieving the predetermined deceleration Grf is referred to as the "D drive source braking torque TbpD". The D actuation position is a forward-driving actuation position for selecting a forward driving position (= D position).D position) of the complex transmission 40. The D position of the complex transmission 40 is a switching position of the complex transmission 40 in which the vehicle 10 can move forward by executing an automatic gear shift control of the complex transmission 40.

[0086] The electronic control unit 90 further comprises status determination means, i.e. a status determination device 99, to achieve a control function to suppress the decrease in drivability when the required deceleration Grdem is reached at the time of deceleration during driving with the driver assistance control CTs.

[0087] The status determination device 99 determines whether the vehicle 10 is operating with the CTs driver assistance control system. If the status determination device 99 determines that the vehicle 10 is operating with the CTs driver assistance control system, the status determination device 99 determines whether the vehicle 10 brakes. For example, if the vehicle 10 is operating with ACC, the status determination device 99 determines whether the vehicle 10 brakes based on whether the required ACC torque Taccdem is a negative value, or whether a negative value than the required ACC torque Taccdem is set and the required ACC torque Taccdem is reduced in the direction of the set negative value.

[0088] When the status determination device 99 detects that the vehicle 10 is driving and braking with the driver assistance control CTs engaged, the status determination device 99 determines whether the deceleration / braking status is a smooth deceleration. The status determination device 99 determines whether the deceleration status is smooth deceleration based on whether the requested deceleration Grdem is equal to or less than the predetermined deceleration Grf. For example, if the vehicle 10 is driving with ACC engaged, the status determination device 99 determines whether the deceleration status is smooth deceleration based on whether the requested ACC torque Taccdem is equal to or greater than the D-drive source braking torque TbpD.That is, the status determination device 99 determines whether the deceleration status is smooth deceleration, based on whether the absolute value of the requested ACC torque Taccdem, which is a negative value, is equal to or less than the absolute value of the D drive source braking torque TbpD.

[0089] When the status determination device 99 determines that the deceleration state is smooth deceleration, in the case of the determination that the vehicle 10 is driving and decelerating with the CTs driver assistance control, the braking control device 96 restricts the downshifting of the complex transmission 40. In particular, the braking control device 96 restricts the downshifting of the complex transmission 40 by prohibiting it. If the deceleration state during driving with the CTs driver assistance control is smooth deceleration, the braking control device 96 achieves the required deceleration Grdem by using the regenerative braking torque Tbr without increasing the absolute value of the engine braking torque Tbe by downshifting the complex transmission 40.

[0090] If the status determination device 99 determines that the vehicle 10 is driving and braking with the CTs driver assistance control system engaged, and that the deceleration condition is a heavy deceleration / hard braking, the braking control device 96 does not restrict the downshifting of the complex transmission 40. During heavy deceleration, the required deceleration Grdem is higher than the predetermined deceleration Grf. If the deceleration condition is heavy deceleration while driving with the CTs driver assistance control system engaged, the braking control device 96 achieves the required deceleration Grdem by using the regenerative braking torque Tbr, while increasing the absolute value of the engine braking torque Tbe by downshifting the complex transmission 40 as needed.

[0091] When the driver performs a driving action while the vehicle is operating with the CTs driving assistance control, the driver barely perceives the change in engine speed or the shift jolt, similar to driving with the manual CTm driving control. Therefore, there is no need to limit the downshifting of the complex transmission 40 if, at the time of deceleration while driving with the CTs driving assistance control, a second required deceleration is included in the required deceleration Grdem, along with the driver's action. That is, whether the downshifting of the complex transmission 40 should be limited can be determined if the second required deceleration is only the required deceleration Grdem set in the CTs driving assistance control.

[0092] If the second requested deceleration, together with the driver's input while driving with the CTs driver assistance control, is not included in the requested deceleration Grdem, the braking control device 96 performs a shift depending on whether the downshifting of the complex transmission 40 is to be limited / restricted based on the requested deceleration Grdem. Examples of the second requested deceleration, together with the driver's input, are a requested deceleration based on a driver braking input, a requested deceleration caused by the driver having set a lower target vehicle speed Vtgt, and a requested deceleration caused by the driver having set a larger vehicle-to-vehicle distance to a vehicle ahead.

[0093] When the wheel brake device 86 uses the wheel brakes while driving with the CTs driving assistance control, a large deceleration Gr is immediately achieved compared to the case where the absolute value of the engine braking torque Tbe is increased by downshifting the complex transmission 40. Therefore, the required deceleration Grdem while driving with the CTs driving assistance control is a deceleration Gr achieved by regenerative braking using the second rotary device MG2 and the engine brake. If the deceleration Gr is increased by the wheel brakes in a state where the required deceleration Grdem is higher than the predetermined deceleration Grf at the time of deceleration while driving with the CTs driving assistance control, the braking control device 96 adjusts the required deceleration Grdem to be equal to or lower than the predetermined deceleration Grf in order to limit downshifting of the complex transmission 40.For example, if the deceleration Gr is increased by the wheel brakes at the time of deceleration while driving with ACC, the braking control device 96 sets the required ACC torque Taccdem so that it is equal to or greater than the D-drive source braking torque TbpD. An example of when the wheel brakes are used while driving with the driver assistance control CTs is when the wheel braking torque Tbw is required because a vehicle ahead has braked hard. Other examples of when the wheel brakes are used while driving with the driver assistance control CTs include when the wheel braking torque Tbw is required because another vehicle moves between vehicle 10 and the vehicle ahead, and therefore a new vehicle ahead is detected.

[0094] Fig. Figure 5 is a flowchart describing a main part of a control operation of the electronic control unit 90 and also describing a control operation for suppressing the decrease in drivability while achieving the required deceleration (Gredem) at the time of deceleration during driving with the CTs driver assistance control system. For example, the control operation is executed repeatedly. Fig. 6, Fig. 7 and Fig. 8 are diagrams that show examples of a time diagram in a case where the flowchart of Fig. The control process shown in section 5 is executed.

[0095] In step (“step” will be omitted in the following) S10, which corresponds to the function of the status determination device 99 in Fig. If S10 corresponds to the status determination device 99, it is first determined whether the vehicle 10 is operating with the CTs driver assistance control system. If the result of the determination in S10 is "No", then in S20, an acceleration run, a steady-state run, or a deceleration run is performed according to the function of, for example, the driving control device 98, under normal control by the manual driving control CTm. If the result of the determination in S10 is "Yes", then in S30, it is determined according to the function of the status determination device 99 whether the vehicle 10 is decelerating. If the result of the determination in S30 is "No", then in S40, an acceleration run or a steady-state run is performed with the CTs driver assistance control system, according to the function of, for example, the driving control device 98. If the result of the determination in S30 is "Yes", then in S50, it is determined according to the function of the status determination device 99 whether the deceleration state is smooth deceleration.If the determination result in S50 is "Yes", downshifting of the complex transmission 40 is prohibited, and the required deceleration Grdem is achieved using the regenerative braking torque Tbr in S60 according to the function of the braking control device 96. In S60, the absolute value of the engine braking torque Tbe is not increased by downshifting the complex transmission 40, but the engine braking torque Tbe can be applied. If the determination result in S50 is "No", downshifting of the complex transmission 40 is not restricted, and the required deceleration Grdem is achieved by using the regenerative braking torque Tbr, while the absolute value of the engine braking torque Tbe is increased by downshifting the complex transmission 40 as needed in S70 according to the function of the braking control device 96.

[0096] Fig. Figure 6 shows an example where smooth deceleration is performed while driving with ACC. At time t1a in Fig. 6. Braking is initiated by reducing the required ACC torque Taccdem while driving with ACC engaged. In a comparative example shown by dashed lines, the complex transmission 40 downshifts by sequentially locking / preventing / prohibiting the simulated gear stages of the complex transmission 40, starting from the side with the high vehicle speed, after the deceleration begins. In this comparative example, NV increases because the engine speed Ne increases with the downshifting of the complex transmission 40. In this embodiment shown by solid lines, the simulated gear stages of the complex transmission 40 on the side with the high vehicle speed are not locked even after the deceleration begins because the required ACC torque Taccdem is equal to or greater than the D-drive source braking torque TbpD. Therefore, the complex transmission 40 does not downshift.In this embodiment, the increase in engine speed Ne at the time of gentle deceleration is suppressed. Thus, the increase in NV is suppressed.

[0097] Fig. Figure 7 shows an example where hard braking is performed while driving with ACC. At time t1b in Fig. 7. Braking is initiated by reducing the required ACC torque Taccdem while driving with ACC engaged. In a comparative example shown by dashed lines, the complex transmission 40 is downshifted by sequentially locking the simulated gear stages of the complex transmission 40, starting from the side with the high vehicle speed, from a point in time before the required ACC torque Taccdem falls below the D-drive source braking torque TbpD after the start of braking. In this embodiment shown by solid lines, the complex transmission 40 is downshifted by sequentially locking the simulated gear stages of the complex transmission 40, starting from the side with the high vehicle speed, from a point in time when the required ACC torque Taccdem falls below the D-drive source braking torque TbpD after the start of braking (see a period after a point in time t2b).In this embodiment, the increase in engine speed Ne is suppressed because the complex transmission 40 is not downshifted until the required ACC torque Taccdem falls below the D-drive source braking torque TbpD. In this embodiment, the absolute value of the engine braking torque Tbe is increased by downshifting the complex transmission 40 when the required ACC torque Taccdem falls below the D-drive source braking torque TbpD. Thus, the required deceleration Grdem is adequately achieved at the time of heavy deceleration. When the required ACC torque Taccdem increases, the locking of the simulated gear stages of the complex transmission 40 is sequentially terminated, starting from the side with the low vehicle speed.

[0098] Fig. Figure 8 shows an example where the wheel brakes are used when heavy deceleration is performed while driving with ACC. At time t1c in Fig. 8. Braking is initiated by reducing the required ACC torque Taccdem while driving with ACC. In a comparative example, shown by dashed lines, and in this embodiment, shown by solid lines, the process is similar to that described in Fig. 7, until a preceding vehicle is detected (see time t2c) and the wheel braking torque Tbw is applied. In both the comparative example and this embodiment, the required ACC torque Taccdem is adjusted to the D drive source braking torque TbpD (see a time interval after time t3c) when the wheel braking torque Tbw is used in a state where the required ACC torque Taccdem is less than the D drive source braking torque TbpD.

[0099] According to the embodiment described above, regenerative braking is performed using the second rotary device MG2 at the time of deceleration while driving with the CTs driver assistance control. If the required deceleration Grdem is equal to or less than the predetermined deceleration Grf, downshifting of the complex transmission 40 is restricted. If the required deceleration Grdem is greater than the predetermined deceleration Grf, downshifting of the complex transmission 40 is not restricted. In this way, the deceleration Gr of the vehicle 10 is controlled. During gentle deceleration, the increase in NV with the increase in engine speed Ne is suppressed, and jerky shifting is prevented. During hard braking, a large deceleration Gr is easily achieved by downshifting.Thus, the decrease in drivability can be suppressed by achieving the required deceleration Grdem at the time of deceleration during driving with the CTs driver assistance control system.

[0100] According to this embodiment, the predetermined deceleration Grf is the maximum value of the deceleration Gr achievable by regenerative braking using the second rotary device MG2. During gentle deceleration, the required deceleration Grdem can be achieved by regenerative braking, although the downshifting of the complex transmission 40 is limited.

[0101] According to this embodiment, downshifting of the complex transmission 40 is limited by locking / prohibiting downshifting. During gentle deceleration, the increase in NV with the increase in engine speed Ne is reliably suppressed, and jerky shifting is reliably suppressed.

[0102] According to this embodiment, if the second required deceleration, together with the driver's input while driving with the CTs driver assistance control system, is not included in the required deceleration Grdem, a shift is performed depending on whether the downshifting of the complex transmission 40 is to be limited based on the required deceleration Grdem. Thus, the increase in NV and the jerky shifting are easily suppressed if the driver does not apply the brakes or perform any other action to reduce the vehicle speed V during deceleration.

[0103] According to this embodiment, when increasing the deceleration Gr by the wheel brakes in the state where the required deceleration Grdem to be achieved by regenerative braking using the second rotary device MG2 and the engine brake is higher than the predetermined deceleration Grf at the time of deceleration while driving with the CTs driver assistance control, the required deceleration Grdem is set to be equal to or lower than the predetermined deceleration Grf. This suppresses downshifting of the complex transmission 40 and generates a large deceleration Gr with good responsiveness from the wheel brakes.

[0104] According to this embodiment, the driving assistance control CTs is the driving control for driving the vehicle 10, at least by automatically controlling the vehicle speed V based on the vehicle environment information Iard. Thus, the required deceleration Grdem is achieved in a suitable manner, and the vehicle speed V is controlled appropriately at the time of deceleration while driving with the driving assistance control CTs.

[0105] A further embodiment of the present invention is described below. In the following description, parts common to the embodiments are represented by the same reference numerals to avoid describing them separately. Second embodiment

[0106] Fig. Figure 9 is a diagram describing the overall structure of a vehicle 100 to which the present invention is applied. The vehicle 100 of this embodiment differs from the vehicle 10 of the first embodiment.

[0107] In Fig. Figure 9, in comparison to the continuously variable transmission unit 20 of vehicle 10, further features a brake B0 and a clutch C0. The brake B0 is arranged between the sun gear S0 and the housing 18. The clutch C0 is arranged between the sun gear S0 and the carrier CA0.

[0108] The electric continuously variable transmission unit 102 functions as an electric continuously variable transmission similar to the continuously variable transmission unit 20 when both the clutch C0 and the brake B0 are disengaged. The electric continuously variable transmission unit 102 is in a non-differential state in which differential action is impossible when the clutch C0 or the brake B0 is engaged. In a non-differential state in which the clutch C0 is engaged, the continuously variable electric transmission unit 102 is in a stepped gear-shifting state to function as a transmission in which the gear ratio γ0 is set to "1".In a non-differential state, with the brake B0 engaged, the continuously variable electric transmission unit 102 is in a stepped gear shift state to function as a speed increaser transmission, with the gear ratio γ0 set to a value less than “1”.

[0109] A mechanical stepped transmission unit 104 of the vehicle 100 is a well-known planetary automatic transmission comprising a plurality of planetary gear sets and a plurality of engagement devices similar to the stepped transmission unit 22 of the vehicle 10.

[0110] A complex transmission 106, which is a complete transmission comprising a combination of the electric continuously variable transmission unit 102 and the mechanical stepped transmission unit 104, is an automatic transmission that forms part of the power transmission path between the internal combustion engine 12 and the drive wheels 14, similar to the complex transmission 40 of the vehicle 10. The complex transmission 106 can operate similarly to the complex transmission 40 when neither the clutch C0 nor the brake B0 is engaged. When the clutch C0 or the brake B0 is engaged, the complex transmission 106 can operate as a stepped transmission with a plurality of gear ratios that differ in the gear ratio γt of the entire complex transmission 106.

[0111] Although the embodiments of the present invention are described in detail above with reference to the drawings, the present invention is also applied to other embodiments.

[0112] For example, in the embodiments described above, if the required deceleration Grdem is equal to or less than the predetermined deceleration Grf while driving with the CTs driver assistance control, downshifting of the complex transmission 40 is prohibited, but the engine braking torque Tbe can be applied. In the continuously variable transmission unit 20, the engine speed Ne can be kept at zero, for example, by idling the first rotary device MG1 through negative rotation in the no-load condition. Thus, engine braking can be prevented if downshifting of the complex transmission 40 is prohibited in the case where the required deceleration Grdem is equal to or less than the predetermined deceleration Grf while driving with the CTs driver assistance control.This means that the braking control device 96 generates the deceleration Gr through regenerative braking using the second rotary device MG2 without applying the engine brake if the required deceleration Grdem is equal to or less than the predetermined deceleration Grf, and generates the deceleration Gr through the engine brake and regenerative braking using the second rotary device MG2 if the required deceleration Grdem is greater than the predetermined deceleration Grf. If the required deceleration Grdem is equal to or less than the predetermined deceleration Grf, the deceleration Gr is generated through regenerative braking using the second rotary device MG2 without using the engine brake. Therefore, during gentle deceleration, the required deceleration Grdem can be achieved even though downshifting of the complex transmission 40 is prohibited.The braking torque Tb is achieved solely through regenerative braking using the second rotary device MG2. This improves energy efficiency. If the required deceleration Grdem is higher than the predetermined deceleration Grf, the deceleration Gr is generated by the engine brake and regenerative braking using the second rotary device MG2. Therefore, during heavy deceleration, the required deceleration Grdem can be achieved by increasing the friction of the internal combustion engine 12 through downshifting of the complex transmission 40.

[0113] In the embodiments described above, downshifting of the complex transmission 40 is restricted by prohibiting downshifting altogether, but the present invention is not limited to this case. For example, downshifting of the complex transmission 40 can be restricted such that the complex transmission 40 downshifts only once instead of twice or three times. Even in this case, predetermined effects can be achieved during gentle deceleration, namely that the increase in NV along with the increase in engine speed Ne is suppressed, and jerky shifting is prevented.

[0114] In the embodiments described above, the continuously variable transmission unit 20 can include a locking mechanism that can fix the carrier CA0 in a rotationally fixed position. Examples of the locking mechanism are a one-way coupling with which the coupling shaft 30 can be attached to the housing 18. Other examples of the locking mechanism are a jaw coupling, a hydraulic friction engagement device with a clutch or brake, a dry engagement device, an electromagnetic friction engagement device, and an engagement device with a magnetic particle coupling that can selectively couple the coupling shaft 30 to the housing 18. The differential mechanism 34 can be a double-pinion planetary gear set. The differential mechanism 34 can have four or more rotating elements by coupling a plurality of planetary gear sets together.The differential mechanism 34 can be a differential gear unit comprising a pinion driven by the internal combustion engine 12 and a pair of bevel gears meshing with the pinion, wherein the first rotating device MG1 and the intermediate gear element 32 are each coupled to the bevel gears. The differential mechanism 34 can be a mechanism constructed such that two or more planetary gear sets are coupled to each other by a subset of their rotating elements, and the internal combustion engine, the rotating devices, and the drive wheels are coupled to the rotating elements of the planetary gear sets to transmit drive energy.

[0115] The embodiments described above refer to the example in which the 10 types of simulated gear stages are assigned to the four types of automatic transmission (AT) gear stages, but the present invention is not limited to this example. The number of simulated gear stages can preferably be equal to or greater than the number of AT gear stages. The number of simulated gear stages can be equal to the number of AT gear stages, but is preferably greater than the number of AT gear stages. For example, it is appropriate for the number of simulated gear stages to be twice as large as or greater than the number of AT gear stages. The AT gear stages are engaged such that the rotational speed of the intermediate gear element 32 or of the second rotary device MG2 coupled to the intermediate gear element 32 is maintained within a predetermined speed range.The simulated gear ratios are engaged to maintain the engine speed (Ne) within a predetermined range. The number of automatic transmission (AT) gear ratios and simulated gear ratios is determined as needed.

[0116] In the embodiments described above, vehicle 10 with the complex transmission 40 and vehicle 100 with the complex transmission 106 are exemplary embodiments of the vehicle to which the present invention is applied. The vehicle is not limited to vehicle 10 or vehicle 100. The present invention is also applicable to a vehicle having a single automatic transmission. That is to say, the present invention is applicable to a vehicle having an internal combustion engine, an automatic transmission forming part of an energy transmission path between the internal combustion engine and a drive wheel, and a rotary device coupled to the drive wheel for transmitting drive energy.Examples of the automatic transmission include an automatic transmission comprising only the continuously variable transmission unit 20, an automatic transmission comprising only the stepped transmission unit 22, a generally known synchronously meshing parallel two-shaft automatic transmission comprising a dual-clutch transmission (DCT), and a generally known continuously variable belt transmission. The rotary device may be coupled to the drive wheel via the automatic transmission or without intervention of the automatic transmission to transmit drive energy. The rotary device may be coupled to drive wheels (e.g., front wheels) to transmit drive energy, and these drive wheels are distinct from drive wheels (e.g., rear wheels) to which a drive force from the internal combustion engine is transmitted. In this case, the vehicle is an all-wheel-drive vehicle.

Claims

Control device for a vehicle (10; 100) with an internal combustion engine (12), with an automatic transmission (40; 106) which forms part of an energy transmission path between the internal combustion engine (12) and a drive wheel (14), and with a rotary device (MG2) which is coupled to the drive wheel (14) to transmit drive energy, wherein the control device has an electronic control unit (90) which is configured to: perform a driver assistance control for driving the vehicle (10, 100) at least by automatically controlling a vehicle speed independently of any driving action by a driver;to perform regenerative braking using the rotary device (MG2) at a time of deceleration while driving with the driver assistance control and to limit downshifting of the automatic transmission (40, 106) when a required deceleration amount (Grdem) for the vehicle (10, 100) is equal to or lower than a predetermined deceleration amount (Grf);and to perform regenerative braking using the rotary device (MG2) at the time of deceleration while driving with the driver assistance control and not to restrict downshifting if the requested deceleration amount (Grdem) is higher than the predetermined deceleration amount (Grf), wherein the electronic control unit (90) is configured to perform shifting depending on whether downshifting is to be restricted on the basis of the requested deceleration amount (Grdem), if a second requested deceleration amount for the vehicle (10, 100) associated with an actuation by the driver is not included in the requested deceleration amount (Grdem) while driving with the driver assistance control, the requested deceleration amount (Grdem) being a deceleration amount (Gr) achievable by regenerative braking and by engine braking using the friction of the internal combustion engine (12);and the electronic control unit (90) is configured to set the requested deceleration amount (Grdem) equal to or lower than the predetermined deceleration amount (Grf) when the deceleration amount (Gr) is increased by a wheel brake in a state where the requested deceleration amount (Grdem) is higher than the predetermined deceleration amount (Grf) at the time of deceleration during driving with the driver assistance control. Control device according to claim 1, wherein the predetermined deceleration amount (Grf) is a predetermined maximum value of a deceleration amount (Gr) achievable by regenerative braking. Control device according to claim 1 or 2, wherein the electronic control unit (90) is configured to restrict downshifting by prohibiting downshifting. Control device according to claim 3, wherein the electronic control unit (90) is configured to: generate a deceleration amount (Gr) by regenerative braking without using an engine brake using friction of the internal combustion engine (12) when the required deceleration amount (Grdem) is equal to or lower than the predetermined deceleration amount (Grf); and generate the deceleration amount (Gr) by the engine brake and by regenerative braking when the required deceleration amount (Grdem) is higher than the predetermined deceleration amount (Grf). Control device according to one of claims 1 to 4, wherein the electronic control unit (90) is configured to drive the vehicle (10; 100) at least by automatically controlling the vehicle speed based on information about the vehicle's (10, 100) surroundings.

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