Vehicle control device

Abstract

To enable a vehicle to start from a stopping / power generation mode while suppressing starting shock.SOLUTION: A control system executes a stopping / power generation mode in which a starting clutch is controlled in a release state, under a situation where a vehicle is stopped, a lock-up clutch is controlled in an engagement state, an engine is controlled in an operation state and a motor for power generation is controlled in a power generation state. The control system, after a starting condition is satisfied during execution of the stopping / power generation mode, controls torque for a motor for travelling at a braking side, when switching the starting clutch from the release state into the engagement state to start the vehicle, while holding the lock-up clutch in the engagement state.SELECTED DRAWING: Figure 12

Description

[Technical Field]

[0001] The present invention relates to a vehicle control device provided in a hybrid vehicle. [Background technology]

[0002] Hybrid vehicles equipped with an engine, a traction motor, and a power generation motor have been developed (see Patent Documents 1 to 4). Hybrid vehicles also have a power generation mode in which the engine is separated from the wheels by releasing the forward clutch or the like, and the power generation motor generates electricity using the engine while the vehicle is stationary. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3601193 [Patent Document 2] Patent No. 3963047 [Patent Document 3] Patent No. 5330130 [Patent Document 4] Patent No. 5900142 Summary of the Invention [Problem to be solved by the invention]

[0004] When the vehicle is in a stationary power generation mode, the lockup clutch of the torque converter is often engaged to avoid a decrease in power generation efficiency due to agitation loss in the torque converter. When starting the vehicle from this stationary power generation mode, it is considered to switch the forward clutch from a released state to an engaged state without disengaging the currently engaged lockup clutch in order to improve start responsiveness. However, switching the forward clutch from a released state to an engaged state while keeping the lockup clutch engaged is likely to cause a start shock, which can be a cause of discomfort to the driver. For this reason, there is a need to start the vehicle from the stationary power generation mode while suppressing the start shock.

[0005] An object of the present invention is to start a vehicle from a stationary power generation mode while suppressing start shock. [Means for solving the problem]

[0006] A vehicle control device in one embodiment is a vehicle control device provided in a hybrid vehicle, and includes: a traction motor connected to at least one of a first wheel and a second wheel; an engine connected to at least one of the first wheel and the second wheel via a power transmission path; a starting clutch provided in the power transmission path; a torque converter provided in the power transmission path and positioned between the engine and the starting clutch, the torque converter including a lock-up clutch; a power generation motor connected to the engine; a processor and a memory connected to each other so as to be able to communicate with each other; and a control system for controlling the starting clutch and the lock-up clutch, wherein the control system executes a stationary power generation mode in which, while the vehicle is stopped, it controls the starting clutch to a released state, the lock-up clutch to an engaged state, the engine to an operating state, and the generator motor to a power generating state, and when a starting condition is met while the stationary power generation mode is being executed, the control system controls the torque of the traction motor on the braking side when the starting clutch is switched from a released state to an engaged state while maintaining the lock-up clutch in an engaged state to start the vehicle. [Effects of the Invention]

[0007] In one embodiment, when a start condition is met while the vehicle is in the standstill power generation mode, the vehicle control device controls the torque of the traction motor on the braking side when the lockup clutch is held engaged and the start clutch is switched from a released state to an engaged state to start the vehicle, thereby making it possible to start the vehicle from the standstill power generation mode while suppressing start shock. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram showing an example of the configuration of a hybrid vehicle equipped with a vehicle control device according to an embodiment of the present invention; [Figure 2] FIG. 2 is a diagram illustrating an example of the configuration of a powertrain and a rear drive unit. [Figure 3]FIG. 2 is a diagram illustrating an example of a powertrain, a rear drive unit, and a control system. [Figure 4] FIG. 2 is a diagram simply illustrating the basic structure of each control unit. [Figure 5] FIG. 10 is a diagram illustrating an execution state of a lockup start mode. [Figure 6] FIG. 10 is a diagram showing an execution state of a torque converter start mode. [Figure 7] FIG. 10 is a diagram showing the execution status of a stationary power generation mode. [Figure 8] 10 is a flowchart showing an example of a procedure for executing target torque setting control. [Figure 9] FIG. 4 is a diagram illustrating an example of axle torque. [Figure 10] FIG. 4 is a diagram illustrating an example of axle torque. [Figure 11] 5A and 5B are diagrams illustrating an example of an axle torque, a differential torque, and a target motor torque. [Figure 12] 10 is a timing chart showing an example of an execution state of a lockup start mode. [Figure 13] 10A and 10B are diagrams illustrating other examples of mounting locations of the power generating motor. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. In the following description, identical or substantially identical configurations and elements are designated by the same reference numerals and will not be described repeatedly.

[0010] [Powertrain and rear drive unit] Fig. 1 is a diagram showing an example of the configuration of a hybrid vehicle 11 equipped with a vehicle control device 10 according to one embodiment of the present invention. As shown in Fig. 1, the hybrid vehicle 11 is equipped with a powertrain 14 including an engine 12 and a transmission 13. Rear wheels 18 are connected to an output shaft 15 of the powertrain 14 via a propeller shaft 16 and a rear drive unit 17. A front differential 19 is incorporated into the transmission 13, and front wheels 20 are connected to the front differential 19.

[0011] FIG. 2 is a diagram showing an example configuration of the powertrain 14 and the rear drive unit 17. As shown in FIG. 2, the powertrain 14 is provided with a center differential 22 consisting of a planetary gear mechanism 21. The planetary gear mechanism 21 of the center differential 22 has a ring gear R (also called an internal gear), a pinion P meshing with the ring gear R, a carrier C that rotatably supports the pinion P, and a sun gear S meshing with the pinion P. The engine 12 is connected to the carrier C via an input path 23, the rear wheels 18 are connected to the ring gear R via a rear wheel output path 24, and the front wheels 20 are connected to the sun gear S via a front wheel output path 25. The center differential 22 is provided with a limited slip clutch 26 that connects the ring gear R and the carrier C to each other.

[0012] An input path 23 connecting the engine 12 and the carrier C is provided with a torque converter 30, a forward / reverse switching mechanism 31, and a continuously variable transmission 32. The torque converter 30 provided in the input path 23 has a pump impeller 35 connected to a crankshaft 33 via a front cover 34, and a turbine runner 37 facing the pump impeller 35 and connected to a turbine shaft 36. The torque converter 30 also has a lock-up clutch 39 equipped with a lock-up piston 38. The torque converter 30 is divided into an apply chamber 40 and a release chamber 41, separated by the lock-up piston 38. By increasing the hydraulic pressure in the apply chamber 40 and decreasing the hydraulic pressure in the release chamber 41, the lock-up piston 38 is pressed against the front cover 34, and the lock-up clutch 39 is switched to an engaged state. On the other hand, by increasing the hydraulic pressure in the release chamber 41 and decreasing the hydraulic pressure in the apply chamber 40, the lock-up piston 38 is moved away from the front cover 34, and the lock-up clutch 39 is switched to a disengaged state.

[0013] The forward / reverse switching mechanism 31 provided in the input path 23 has a double-pinion planetary gear train 50, a forward clutch 51 that connects a sun gear 50s and a carrier 50c of the planetary gear train 50 to each other, and a reverse clutch 53 that fixes a ring gear 50r of the planetary gear train 50 to a transmission case 52. When the hybrid vehicle 11 is driven forward, the forward clutch 51 is engaged and the reverse clutch 53 is disengaged. This allows the input-side sun gear 50s and the output-side carrier 50c to rotate integrally, allowing the continuously variable transmission 32 to rotate in the forward direction. On the other hand, when the hybrid vehicle 11 is driven backward, the reverse clutch 53 is engaged and the forward clutch 51 is disengaged. This allows the input-side sun gear 50s and the output-side carrier 50c to rotate in opposite directions, allowing the continuously variable transmission 32 to rotate in the reverse direction.

[0014] The continuously variable transmission 32 provided in the input path 23 has a primary pulley 61 provided on a primary shaft 60 and a secondary pulley 63 provided on a secondary shaft 62. A drive chain 64 that transmits power between the pulleys 61, 63 is wound around the primary pulley 61 and the secondary pulley 63. A primary chamber 65 is provided in the primary pulley 61, and a secondary chamber 66 is provided in the secondary pulley 63. By controlling the hydraulic pressure supplied to the primary chamber 65 and the secondary chamber 66, the pulley groove width can be changed to vary the winding diameter of the drive chain 64, thereby enabling continuously variable speed change from the primary shaft 60 to the secondary shaft 62.

[0015] As described above, the front wheels 20 are connected to the sun gear S of the center differential 22 via the front wheel output path 25. The gear train 70 and the front differential 19 are provided in the front wheel output path 25, which connects the front wheels 20 and the sun gear S. That is, a drive gear 70a is connected to the sun gear S of the center differential 22, and a front wheel drive shaft 71 is connected to a driven gear 70b that meshes with the drive gear 70a. A pinion 72 is provided at the tip of the front wheel drive shaft 71, and a bevel gear 74 fixed to a differential case 73 of the front differential 19 meshes with the pinion 72. The front wheels 20 are connected to a front shaft 75 extending from the front differential 19.

[0016] Furthermore, rear wheels 18 are connected to a ring gear R of the center differential 22 via a rear wheel output path 24. A propeller shaft 16 and a rear drive unit 17 are provided in the rear wheel output path 24, which connects the rear wheels 18 and the ring gear R. The rear drive unit 17 has a traction motor 80 and a rear differential 81. A rotor shaft 82 connected to a rotor 80r of the traction motor 80 is provided with a bevel gear 83, and a pinion 84 connected to the propeller shaft 16 is meshed with this bevel gear 83. A drive gear 86 is connected to the rotor shaft 82 of the traction motor 80 via a rear clutch 85. A driven gear 88 fixed to a differential case 87 of the rear differential 81 is meshed with the drive gear 86. The rear wheels 18 are connected to a rear shaft 89 extending from the rear differential 81.

[0017] As explained above, the engine 12 is connected to the front wheels 20 and the rear wheels 18 via a power transmission path 90, which is made up of the input path 23, the front wheel output path 25, and the rear wheel output path 24. The traction motor 80 is connected to the rear wheels 18 via the rear wheel output path 24. The power transmission path 90 connecting the engine 12 to the front and rear wheels 18, 20 is provided with a forward clutch (starting clutch) 51 of the forward / reverse switching mechanism 31. The power transmission path 90 connecting the engine 12 to the front and rear wheels 18, 20 is also provided with a torque converter 30 equipped with a lock-up clutch 39. The torque converter 30 provided in the power transmission path 90 is located between the engine 12 and the forward clutch 51.

[0018] In the example shown in FIG. 2 , the engine 12 is coupled to both the front wheels 20 and the rear wheels 18, but this is not limited thereto, and the engine 12 may be coupled only to the front wheels 20, or the engine 12 may be coupled only to the rear wheels 18. Furthermore, in the example shown, the traction motor 80 is coupled to the rear wheels 18, but this is not limited thereto, and the traction motor 80 may be coupled to the front wheels 20, or the traction motor 80 may be coupled to both the front wheels 20 and the rear wheels 18. In other words, it is sufficient that the engine 12 is coupled to at least one of the front wheels 20 and the rear wheels 18, and the traction motor 80 is coupled to at least one of the front wheels 20 and the rear wheels 18. In other words, one of the front wheels 20 and the rear wheels 18 functions as a first wheel, and the other of the front wheels 20 and the rear wheels 18 functions as a second wheel.

[0019] [Control System] FIG. 3 is a diagram showing an example of the powertrain 14, rear drive unit 17, and control system 91. As shown in FIG. 3, the powertrain 14 is provided with a valve unit 92 including a plurality of electromagnetic valves and oil passages in order to control the torque converter 30, forward / reverse switching mechanism 31, continuously variable transmission 32, and other components incorporated in the powertrain 14. An oil pump 93 driven by the engine 12, etc., is connected to the valve unit 92. The supply destination, pressure, etc. of the hydraulic oil discharged from the oil pump 93 are controlled by the valve unit 92, and the hydraulic oil is supplied to the continuously variable transmission 32, torque converter 30, forward / reverse switching mechanism 31, etc. A transmission control unit 94 is connected to the valve unit 92 in order to control the continuously variable transmission 32, etc. via the valve unit 92.

[0020] A battery pack 96 is connected to the stator 80s of the traction motor 80 via an inverter 95. The battery pack 96 is provided with a battery module 97 consisting of a plurality of battery cells, and a battery control unit 98 that monitors the charging and discharging of the battery module 97. The battery pack 96 is also provided with a battery sensor 99 that detects the charging and discharging current, terminal voltage, etc. The battery control unit 98 has a function of calculating the SOC (State of Charge) that is the state of charge of the battery module 97 based on the charging and discharging current, terminal voltage, etc. detected by the battery sensor 99. The SOC of the battery module 97 is a ratio that indicates the remaining amount of electricity stored in the battery module 97, and is the ratio of the stored amount to the fully charged capacity of the battery module 97.

[0021] A travel motor control unit 100 is connected to the inverter 95 to control the travel motor 80 via the inverter 95. The travel motor control unit 100 controls the inverter 95, which is made up of a plurality of switching elements and the like, to control the current flow state of the stator 80s and thereby control the torque of the travel motor 80. When the travel motor 80 is controlled to be in a power running state, power is supplied from the battery module 97 to the stator 80s via the inverter 95. On the other hand, when the travel motor 80 is controlled to be in a power generating state, power is supplied from the stator 80s to the battery module 97 via the inverter 95.

[0022] A rotor 102r of a generator motor 102 is connected to the crankshaft 33 of the engine 12 via a belt mechanism 101. An inverter 103 is connected to a stator 102s of the generator motor 102, and the above-mentioned battery pack 96 is connected to this inverter 103. A generator motor control unit 104 is connected to the inverter 103 to control the generator motor 102 via the inverter 103. The generator motor control unit 104 controls the inverter 103, which is made up of a plurality of switching elements, thereby controlling the current flow state of the stator 102s and the torque of the generator motor 102. When the generator motor 102 is controlled to be in a power generating state, power is supplied from the stator 102s to the battery module 97 via the inverter 103. On the other hand, when the generator motor 102 is controlled to be in a power running state, power is supplied from the battery module 97 to the stator 102s via the inverter 103. The generator motor 102 may be made to function as a starter motor for starting the engine by powering the generator motor 102 when the engine is started.

[0023] A throttle valve 106 that adjusts the amount of intake air is provided in an intake manifold 105 of the engine 12. The engine 12 is also provided with an injector 107 that injects fuel into the intake port and cylinder, and an ignition device 108 that includes an igniter, a spark plug, etc. Furthermore, an engine control unit 109 is connected to the throttle valve 106, injector 107, ignition device 108, etc. in order to control the engine 12 via the throttle valve 106, etc.

[0024] The vehicle control device 10 is provided with a control system 91 consisting of a plurality of electronic control units for controlling the powertrain 14 and the like. The electronic control units constituting the control system 91 include the aforementioned transmission control unit 94, battery control unit 98, traction motor control unit 100, generator motor control unit 104, and engine control unit 109, as well as a vehicle control unit 110 that outputs control signals to these control units 94, 98, 100, 104, and 109. These control units 94, 98, 100, 104, 109, and 110 are connected to each other so as to be able to communicate with each other via an in-vehicle network 111 such as a CAN or LIN. The vehicle control unit 110 sets operation targets for the engine 12, the continuously variable transmission 32, and the like based on input information from the various control units 94, 98, 100, 104, 109, and 110 and various sensors described below. Then, the control signals are generated according to the operation targets of the engine 12, the continuously variable transmission 32, etc., and these control signals are output to the various control units 94, 98, 100, 104, and 109.

[0025] Sensors connected to vehicle control unit 110 include a vehicle speed sensor 112 that detects the vehicle speed, which is the traveling speed of hybrid vehicle 11, and an engine rotation speed sensor 113 that detects the engine rotation speed, which is the rotation speed of engine 12. Sensors connected to vehicle control unit 110 also include an accelerator sensor 114 that detects the operation status of an accelerator pedal, and a brake sensor 115 that detects the operation status of a brake pedal. Sensors connected to vehicle control unit 110 further include a primary rotation speed sensor 116 that detects the rotation speed of primary pulley 61, and a secondary rotation speed sensor 117 that detects the rotation speed of secondary pulley 63. Furthermore, a start switch 118 that is operated by the driver when starting up control system 91 is connected to vehicle control unit 110.

[0026] FIG. 4 is a diagram simply illustrating the basic structure of each of the control units 94, 98, 100, 104, 109, and 110. As shown in FIG. 4, each of the control units 94, 98, 100, 104, 109, and 110 includes a microcontroller 122 incorporating a processor 120, a memory 121, and the like. A predetermined program is stored in the memory 121, and the processor 120 executes an instruction set of the program. The processor 120 and the memory 121 are connected to each other so as to be able to communicate with each other. In the illustrated example, one processor 120 and one memory 121 are incorporated in the microcontroller 122, but this is not limiting. Multiple processors 120 may be incorporated in the microcontroller 122, and multiple memories 121 may be incorporated in the microcontroller 122.

[0027] Each of the control units 94, 98, 100, 104, 109, and 110 is also provided with an input conversion circuit 123, a drive circuit 124, a communication circuit 125, an external memory 126, a power supply circuit 127, and the like. The input conversion circuit 123 converts signals input from various sensors into signals that can be input to the microcontroller 122. The drive circuit 124 generates drive signals for actuators such as the valve unit 92 and inverters 95 and 103, based on signals output from the microcontroller 122. The communication circuit 125 converts signals output from the microcontroller 122 into communication signals directed to other control units. The communication circuit 125 also converts communication signals received from other control units into signals that can be input to the microcontroller 122. The power supply circuit 127 supplies a stable power supply voltage to the microcontroller 122, the input conversion circuit 123, the drive circuit 124, the communication circuit 125, the external memory 126, and the like. Furthermore, the external memory 126, such as a nonvolatile memory, stores data that should be retained even when power is off.

[0028] [Launch Mode] The start modes executed when the vehicle starts will now be described. Fig. 5 is a diagram showing the execution status of the lock-up start mode, and Fig. 6 is a diagram showing the execution status of the torque converter start mode. The control system 91 has, as start modes executed when the vehicle starts, a lock-up start mode (first start mode) in which the lock-up clutch 39 is engaged, and a torque converter start mode (second start mode) in which the lock-up clutch 39 is released. The arrows shown in Figs. 5 and 6 indicate the transmission path of the torque of the engine 12 (hereinafter referred to as engine torque).

[0029] As shown in Figure 5, in the lock-up start mode, the forward clutch 51 is switched from a released state to an engaged state while the lock-up clutch 39 remains engaged. Thus, in the lock-up start mode, engine torque is transmitted to the front wheels 20 and the rear wheels 18 via the forward clutch 51, which is engaged after passing through a slip state, without being amplified by the torque converter 30. On the other hand, as shown in Figure 6, in the torque converter start mode, the forward clutch 51 is maintained in an engaged state and the lock-up clutch 39 is maintained in a released state. Thus, in the torque converter start mode, the torque converter 30 is activated by the release of the lock-up clutch 39, and the engine torque amplified via the torque converter 30 is transmitted to the front wheels 20 and the rear wheels 18.

[0030] [Stopped power generation mode] Next, the stationary vehicle power generation mode will be described. FIG. 7 is a diagram showing the state in which the stationary vehicle power generation mode is being executed. The arrows in FIG. 7 indicate the transmission path of engine torque. As shown in FIG. 7, when the stationary vehicle power generation mode is being executed, with the hybrid vehicle 11 at a standstill, the forward clutch 51 is controlled to a released state, the lock-up clutch 39 is controlled to an engaged state, the engine 12 is controlled to an operating state, and the generator motor 102 is controlled to a power generating state. This allows the generator motor 102 to be rotationally driven by the engine 12, making it possible to control the generator motor 102 to a power generating state while the vehicle 11 is stopped.

[0031] In the stationary power generation mode, the lock-up clutch 39 of the torque converter 30 is engaged to restrict the relative rotation between the pump impeller 35 and the turbine runner 37. This prevents a decrease in engine output due to stirring loss in the torque converter 30, and increases the power generated by the power generator motor 102. This stationary power generation mode is executed, for example, when the SOC of the battery module 97 falls below a predetermined threshold. It goes without saying that in the stationary power generation mode shown in the figure, not only is the forward clutch 51 of the forward / reverse switching mechanism 31 disengaged, but the reverse clutch 53 of the forward / reverse switching mechanism 31 is also disengaged.

[0032] If the driver releases the brake pedal while the vehicle is in the stationary power generation mode, the control system 91 executes the lockup start mode described above to quickly start the hybrid vehicle 11. That is, as shown in FIG. 5 , the control system 91 switches the forward clutch 51 from a released state to an engaged state while keeping the lockup clutch 39 engaged, thereby starting the vehicle 11. This allows engine torque to be transmitted to the front wheels 20 and the rear wheels 18 without temporarily releasing the lockup clutch 39 and operating the torque converter 30, allowing the vehicle 11 to quickly start from the stationary power generation mode. Note that when starting the vehicle 11 from the stationary power generation mode, power generation by the generator motor 102 may be continued or may be stopped.

[0033] In lock-up start mode, relative rotation between the pump impeller 35 and the turbine runner 37 is not permitted, so torque-boost control is executed in response to a rapid decrease in engine speed, which may cause engine torque to fluctuate and result in a shock when starting. In other words, in lock-up start mode, the engine 12 is directly coupled to the stopped front wheels 20 and rear wheels 18, so engagement of the forward clutch 51 causes a rapid decrease in engine speed. Therefore, torque-boost control is executed to increase engine torque beyond its most recent value in order to prevent engine stall, which may cause a shock when starting due to this fluctuation in engine torque. Therefore, to suppress the shock when starting in lock-up start mode, the control system 91 sets a target motor torque for the traction motor 80 based on the accelerator position, etc., as described below, and controls the traction motor 80 in conjunction with the execution of the lock-up start mode.

[0034] [Target torque setting control] The following describes target torque setting control that sets a target motor torque in accordance with the lock-up start mode. Fig. 8 is a flowchart showing an example of the execution procedure for target torque setting control. Each step shown in the flowchart of Fig. 8 represents processing that is executed by one or more processors 120 that constitute control system 91. Furthermore, the target torque setting control shown in Fig. 8 is control that is executed by control system 91 at predetermined intervals after the driver operates start switch 118 and starts up control system 91, which is made up of vehicle control unit 110 and the like.

[0035] As shown in FIG. 8, in step S10, it is determined whether the stationary vehicle power generation mode is being executed. If it is determined in step S10 that the stationary vehicle power generation mode is being executed, the process proceeds to step S11, where it is determined whether a predetermined start condition is met. This start condition may be, for example, that the brake pedal is released or that the accelerator pedal is depressed. If it is determined in step S11 that the start condition is not met, the process proceeds to step S12, where the target motor torque Tm1 of the traction motor 80 is set to "0," and the process returns to step S10, where it is determined whether the stationary vehicle power generation mode is being executed. In other words, if the start condition of the vehicle 11 is not met, the target motor torque Tm1 remains set to "0," and the stationary vehicle power generation mode continues to be executed.

[0036] On the other hand, if it is determined in step S11 that the start condition for the vehicle 11 is met, that is, if the brake pedal is released, the process proceeds to step S13, where an axle torque Tx1 transmitted from the engine 12 to the front axle 75 and the rear axle 89 is estimated based on the accelerator operation amount (hereinafter referred to as accelerator opening), which is the amount of accelerator pedal depression, and the gear ratio of the continuously variable transmission 32. As shown in FIG. 5, the axle torque (first axle torque) Tx1 is the torque transmitted from the engine 12 to the front axle (axle) 75 and the rear axle (axle) 89 when the vehicle starts in the lock-up start mode. Here, FIG. 9 is a diagram showing an example of the axle torque Tx1. As shown in FIG. 9, the axle torque Tx1 is estimated to be larger as the accelerator opening increases and as the gear ratio becomes lower.

[0037] Once the axle torque Tx1 is estimated in step S13, the process proceeds to step S14, where the axle torque Tx2 transmitted from the engine 12 to the front axle 75 and the rear axle 89 is estimated based on the accelerator opening and the gear ratio. As shown in FIG. 6, the axle torque (second axle torque) Tx2 is the torque transmitted from the engine 12 to the front axle 75 and the rear axle 89 when the vehicle starts in the torque converter start mode. Here, FIG. 10 is a diagram showing an example of the axle torque Tx2. As shown in FIG. 10, the axle torque Tx2 is estimated to be larger as the accelerator opening increases and as the gear ratio becomes lower.

[0038] Once the axle torques Tx1 and Tx2 have been estimated based on the accelerator opening and the gear ratio in this way, the process proceeds to step S15. In step S15, the axle torque Tx1 is subtracted from the axle torque Tx2 to calculate a differential torque (difference) Tx3, and in the following step S16, the target motor torque Tm1 is set based on the differential torque Tx3. In other words, when the vehicle 11 is started from the stationary power generation mode, the lock-up start mode is executed while the traction motor 80 is controlled based on the target motor torque Tm1 set in step S16.

[0039] FIG. 11 is a diagram showing an example of axle torques Tx1 and Tx2, differential torque Tx3, and target motor torque Tm1. FIG. 11 also shows the torques when starting at a predetermined gear ratio. As shown in FIG. 11, when the accelerator pedal position is below a predetermined threshold Xa, the axle torque Tx1 in the lock-up start mode exceeds the axle torque Tx2 in the torque converter start mode. In other words, when the accelerator pedal position is below the predetermined threshold Xa during creep starting, the lock-up start mode is executed when torque-boost control is performed to prevent engine stall. Therefore, the axle torque Tx1 in the lock-up start mode is estimated to be greater than the axle torque Tx2 in the torque converter start mode.

[0040] On the other hand, when the accelerator opening exceeds the predetermined threshold value Xa, the axle torque Tx1 in the lock-up start mode is lower than the axle torque Tx2 in the torque converter start mode. In other words, when the accelerator pedal is depressed to start the vehicle, the lock-up start mode is executed when torque amplification is not performed by the torque converter 30. For this reason, the axle torque Tx1 in the lock-up start mode is estimated to be smaller than the axle torque Tx2 in the torque converter start mode.

[0041] As described above, when the accelerator opening degree is below the predetermined threshold Xa, the axle torque Tx1 exceeds the axle torque Tx2, so the differential torque Tx3 is calculated to be on the negative side (- side), and the target motor torque Tm1 is set to the braking side based on the differential torque Tx3. In other words, when the accelerator opening degree is below the predetermined threshold Xa and the vehicle 11 is started in the lock-up start mode, the target motor torque (target torque value) Tm1 of the traction motor 80 is set to the braking side.

[0042] That is, when the axle torque Tx1 in the lock-up start mode exceeds the axle torque Tx2 corresponding to the torque converter start mode, the target motor torque Tm1 is set to the braking side so as to reduce the axle torque Tx1 toward the axle torque Tx2, as shown by the arrow α1 in Fig. 11. As a result, even when the lock-up start mode is executed, the actual axle torque Ax2 (described later) can be made to approach the axle torque in the torque converter start mode during a normal start, and the vehicle 11 can be started without causing any discomfort to the driver.

[0043] On the other hand, when the accelerator opening exceeds the predetermined threshold Xa, the axle torque Tx1 falls below the axle torque Tx2, so the differential torque Tx3 is calculated to be on the positive side (+ side), and the target motor torque Tm1 is set to the acceleration side based on the differential torque Tx3. In other words, when the accelerator opening exceeds the predetermined threshold Xa and the vehicle 11 is started in the lock-up start mode, the target motor torque Tm1 of the traction motor 80 is set to the acceleration side.

[0044] That is, when the axle torque Tx1 in the lock-up start mode falls below the axle torque Tx2 corresponding to the torque converter start mode, the target motor torque Tm1 is set to the acceleration side so as to increase the axle torque Tx1 toward the axle torque Tx2, as shown by the arrow α2 in Fig. 11. As a result, even when the lock-up start mode is executed, the actual axle torque Ax2 (described later) can be made to approach the axle torque in the torque converter start mode during a normal start, and the vehicle 11 can be started without causing any discomfort to the driver.

[0045] In the above description, when the accelerator opening exceeds the predetermined threshold Xa and the vehicle 11 is started in the lock-up start mode, the target motor torque Tm1 is set to the acceleration side, but this is not limited to this. For example, when the accelerator opening exceeds the predetermined threshold Xa and the vehicle 11 is started in the lock-up start mode, the target motor torque Tm1 may be set to "zero." In this case, the lock-up start mode is executed using only the engine torque.

[0046] [Lock-up launch mode: timing chart] The execution status of the lockup start mode described above will be explained with reference to a timing chart. FIG. 12 is a timing chart showing an example of the execution status of the lockup start mode. The status shown in FIG. 12 is a status where the brake pedal is released during the vehicle-stop power generation mode, causing the hybrid vehicle 11 to creep start. Note that the engine torque TE shown in FIG. 12 refers to engine torque other than the torque consumed by the power generation motor 102, that is, engine torque output from the engine 12 to the torque converter 30. Also, in FIG. 12, the "L / U clutch" refers to the lockup clutch 39.

[0047] 12, at time t1, the stationary power generation mode is executed, so that the forward clutch 51 is controlled to a released state (symbol a1), the lock-up clutch 39 is controlled to an engaged state (symbol b1), and the engine 12 is controlled to an operating state (symbol c1). Subsequently, as shown at time t2, when the brake pedal is released (symbol d1), the torque required for the vehicle 11 increases in conjunction with the brake release (symbol e1). Then, in order to start the vehicle 11 in the lock-up start mode, the engine torque TE increases from its most recent value (symbol f1), and the forward clutch 51 is switched from a released state to an engaged state (symbol a2) while the lock-up clutch 39 is maintained in an engaged state (symbol b2).

[0048] Furthermore, at time t2, engine torque TE is increased (symbol f1) toward target engine torque Te1 in lockup start mode. Note that, because torque-up control is performed to prevent engine stall, target engine torque Te1 in lockup start mode is set higher than target engine torque Te2 in torque converter start mode. Furthermore, at time t2, motor torque TM of travel motor 80 is controlled on the braking side toward target motor torque Tm1 in lockup start mode. In this way, in lockup start mode, engine torque TE increases (arrow β1) due to torque-up control, and motor torque TM is controlled on the braking side to cancel out this increase in engine torque TE (arrow β2).

[0049] As a result, the axle torque Ax1 caused by the engine torque TE is controlled toward the axle torque Tx1 in the lock-up start mode described above, and the axle torque Ax3 caused by the motor torque TM is controlled toward the differential torque Tx3 described above. In other words, the axle torque Ax3 can be generated on the braking side to cancel out the increase in the axle torque Ax1, so that the actual axle torque Ax2 can be made closer to the axle torque Tx2 in the torque converter start mode. As a result, even when starting the vehicle 11 from the stationary power generation mode, the vehicle 11 can be started using the lock-up start mode without causing any discomfort to the driver.

[0050] As shown at time t3, when the vehicle speed stabilizes (symbol g1), the mode shifts from lock-up start mode to torque converter start mode, and normal creep driving is performed. That is, the lock-up clutch 39 is switched from the engaged state to the released state (symbol b3), the engine torque TE is controlled toward the target engine torque Te2 for the torque converter start mode (symbol f2), and the motor torque TM is controlled toward zero (symbol d2).

[0051] The present invention is not limited to the above-described embodiment and may be modified in various ways without departing from the spirit and scope of the present invention. In the above description, the control system 91 is configured with multiple control units 94, 98, 100, 104, 109, and 110, but this is not a limitation. For example, the control system 91 may be configured with a single control unit. In the above description, the power transmission path 90 is provided with a continuously variable transmission 32, but this is not a limitation. The power transmission path 90 may be provided with an automatic transmission including a planetary gear or the like. In the above description, the traction motor 80 is provided in the rear drive unit 17, but this is not a limitation. The traction motor 80 may be provided on the front wheels 20 or the rear wheels 18 as an in-wheel motor, or the traction motor 80 may be provided within the transmission 13. In the illustrated example, the vehicle 11 is equipped with a single traction motor 80, but this is not a limitation. It goes without saying that multiple traction motors may be provided on the vehicle 11.

[0052] In the example shown in FIG. 3, the generator motor 102 is connected via a belt mechanism 101 to the crankshaft 33 protruding from the front end face of the engine 12. However, this is not a limitation, and the generator motor connected to the engine 12 may be provided in another location. Here, FIG. 13 is a diagram showing another example of the mounting location of the generator motors 200, 300. As shown in FIG. 13, the generator motor 200 may be connected to the crankshaft 33 connecting the engine 12 and the torque converter 30. Furthermore, the generator motor 300 may be connected to the turbine shaft 36 connecting the torque converter 30 and the forward / reverse switching mechanism 31. Furthermore, in the example shown in FIG. 3, the forward / reverse switching mechanism 31 is provided on the input side (engine side) of the continuously variable transmission 32. However, this is not a limitation, and the forward / reverse switching mechanism 31 may be provided on the output side (wheel side) of the continuously variable transmission 32. In this case, the generator motor may be connected to the primary shaft 60 or the secondary shaft 62. It goes without saying that the front and rear wheels 18, 20 may be driven by the generator motor by controlling the generator motor to a power running state as required.

[0053] In the example shown in Figure 11, the axle torques Tx1 and Tx2 change along a straight line, but this is not limited thereto, and the axle torques Tx1 and Tx2 may change along a curve. Also, in the example shown in Figure 11, the axle torques Tx1 and Tx2 change continuously, but this is not limited thereto, and the axle torques Tx1 and Tx2 may change in steps. Also, in the above explanation, the axle torques Tx1 and Tx2 are estimated based on the accelerator pedal position and the gear ratio, but this is not limited thereto, and the axle torques Tx1 and Tx2 may be estimated based only on the accelerator pedal position.

[0054] In the above description, when moving the vehicle 11 forward from the stationary vehicle power generation mode to the lock-up start mode, the target motor torque Tm1 of the traction motor 80 is controlled to the braking side, zero, or acceleration side, but this is not limited to this. For example, when moving the vehicle 11 backward from the stationary vehicle power generation mode to the lock-up start mode, the target motor torque Tm1 of the traction motor 80 may be controlled to the braking side, zero, or acceleration side. In this case, the reverse clutch 53 functions as a start clutch. [Explanation of symbols]

[0055] 10 Vehicle control device 11 Hybrid vehicles 12 Engine 18 Rear wheels (1st wheel, 2nd wheel) 20 Front wheels (2nd wheel, 1st wheel) 30 Torque converter 39 Lock-up clutch 51 Forward clutch (starting clutch) 75 Front axle (axle) 80 Drive motor 89 Rear axle (axle) 90 Power transmission path 91 Control System 102 Power generating motor 120 processors 121 memory 200,300 Power generating motor TM Motor torque (torque) TE Engine Torque (torque) Tx1 axle torque (first axle torque) Tx2 axle torque (second axle torque) Tx3 Differential torque (Differential) Tm1 Target motor torque (target torque value) Xa threshold

Claims

1. A vehicle control device provided in a hybrid vehicle, a traction motor connected to at least one of the first wheel and the second wheel; an engine connected to at least one of the first wheel and the second wheel via a power transmission path; a starting clutch provided in the power transmission path; a torque converter provided in the power transmission path between the engine and the starting clutch, the torque converter including a lock-up clutch; a generator motor connected to the engine; a control system including a processor and a memory communicatively connected to each other, the control system controlling the engine, the traction motor, the generator motor, the starting clutch, and the lock-up clutch; and the control system executes a vehicle-stop power generation mode in which, under a condition in which the vehicle is stopped, the start clutch is controlled to a released state, the lock-up clutch is controlled to an engaged state, the engine is controlled to an operating state, and the power generation motor is controlled to a power generating state; When a start condition is met during execution of the stationary power generation mode, the control system controls the torque of the traction motor on the braking side when the start clutch is switched from a released state to an engaged state while maintaining the lock-up clutch in an engaged state to start the vehicle. Vehicle control device.

2. 2. The vehicle control device according to claim 1, When a start condition is satisfied during execution of the stationary vehicle power generation mode, and the start clutch is switched from a released state to an engaged state to start the vehicle, the control system increases the torque of the engine to a value higher than the most recent value and controls the torque of the traction motor on the braking side. Vehicle control device.

3. 3. The vehicle control device according to claim 1, the control system executes a first start mode in which the lock-up clutch is maintained in an engaged state and the start clutch is switched from a released state to an engaged state to start the vehicle, or a second start mode in which the torque converter is operated while the start clutch is maintained in an engaged state to start the vehicle, the control system controls the torque of the traction motor on the braking side when starting the vehicle in the first start mode, and controls the torque of the traction motor on the zero or acceleration side when starting the vehicle in the second start mode. Vehicle control device.

4. 4. The vehicle control device according to claim 3, the control system estimates a first axle torque transmitted from the engine to an axle in the first start mode based on an accelerator operation amount by a driver; the control system estimates a second axle torque transmitted from the engine to the axle in the second start mode based on an accelerator operation amount by a driver; When the vehicle is started in the first start mode, the control system sets a target value of the torque of the traction motor based on a difference between the first axle torque and the second axle torque. Vehicle control device.

5. 5. The vehicle control device according to claim 4, The control system includes: When the accelerator operation amount by the driver is below a threshold value and the vehicle is started in the first start mode, the first axle torque is estimated to be larger than the second axle torque, and a target value of the torque of the traction motor is set to a braking side based on the difference; When the accelerator operation amount by the driver exceeds the threshold value and the vehicle is started in the first start mode, the first axle torque is estimated to be smaller than the second axle torque, and the target value of the torque of the traction motor is set to the acceleration side based on the difference. Vehicle control device.

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