vehicle

Abstract

To provide a vehicle which can prevent a shift shock from occurring in the upshift of a gear shift of a transmission.SOLUTION: A transmission is controlled such that a gear shift gets to a target gear shift based on an accelerator operation quantity and a vehicle speed. A clutch is brought into a completely-engaged state when a target gear shift rotation number as the rotation number of an input shaft of the transmission corresponding to the target gear shift, and is brought into a slip engagement state when the target gear shift rotation number is less than the predetermined rotation number. In such a case, when the target gear shift rotation number is the predetermined rotation number or more, and when it is estimated that the upshift of the gear shift is performed within a predetermined time and the rotation number of the input shaft gets to less than the predetermined rotation number after the upshift, the clutch is brought into the slip engagement state.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a vehicle. [Background technology]

[0002] Conventionally, vehicles of this type have been proposed that include an engine or motor as a drive source and a clutch provided between the drive source and the drive wheels (see, for example, Patent Document 1). In this vehicle, when transitioning between a first mode in which the drive source is controlled in rotation speed and the clutch is placed in a slip-engaged state, and a second mode in which the drive source is controlled in torque and the clutch is placed in a fully engaged state, the transfer torque capacity of the clutch in the slip-engaged state is set to a value obtained by subtracting torque related to the inertia component on the drive source side from a target drive torque set based on the accelerator opening. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2012 / 053576 Summary of the Invention [Problem to be solved by the invention]

[0004] In such vehicles, the clutch is fully engaged when the target gear speed, which is the rotational speed of the input shaft of the transmission corresponding to the target gear of the transmission, is equal to or greater than a predetermined rotational speed, and the clutch is put into a slipping engagement state when the target gear speed is less than the predetermined rotational speed. In this case, if an upshift of the transmission is initiated while the clutch is fully engaged, the rotational speed of the input shaft of the transmission in the gear after the upshift may fall below the predetermined rotational speed, causing the clutch to be put into a slipping engagement state again during the upshift. Switching the clutch from a fully engaged state to a slipping engagement state during an upshift may cause gear shift shock.

[0005] A main object of the vehicle of the present invention is to suppress the occurrence of gear shift shock when upshifting the gear stage of the transmission. [Means for solving the problem]

[0006] The vehicle of the present invention employs the following means to achieve the above-mentioned main object.

[0007] The vehicle of the present invention comprises: The engine and a transmission connected to the drive wheels; a clutch provided between the engine and the transmission; a control device that controls the transmission so that the gear position becomes a target gear position based on an accelerator operation amount and a vehicle speed, and that brings the clutch into a fully engaged state when a target gear position rotation speed, which is the rotation speed of an input shaft of the transmission corresponding to the target gear position, is equal to or greater than a predetermined rotation speed, and brings the clutch into a slipping engaged state when the target gear position rotation speed is less than the predetermined rotation speed; A vehicle comprising: When the target gear speed is equal to or higher than the predetermined speed, the control device predicts that an upshift of the gear will be performed within a predetermined time and, when it predicts that the rotation speed of the input shaft will be less than the predetermined speed after the upshift, brings the clutch into a slip engagement state. The gist of this is as follows.

[0008] In the vehicle of the present invention, the transmission is controlled so that the gear position becomes a target gear position based on the accelerator operation amount and the vehicle speed, and the clutch is fully engaged when a target gear rotation speed, which is the rotation speed of the input shaft of the transmission corresponding to the target gear position, is equal to or greater than a predetermined rotation speed, and is put into a slipping engagement state when the target gear rotation speed is less than the predetermined rotation speed. In this case, when the target gear rotation speed is equal to or greater than the predetermined rotation speed, it is predicted that an upshift of the gear position will be performed within a predetermined time and that the rotation speed of the input shaft will be less than the predetermined rotation speed after the upshift, the clutch is put into a slipping engagement state. This makes it possible to prevent the clutch from being switched from a slipping engagement state to a fully engaged state when the target gear rotation speed rises from less than the predetermined rotation speed to equal to or greater than the predetermined rotation speed before an upshift of the transmission, and then the clutch is switched back into a slipping engagement state when the target gear rotation speed falls below the predetermined rotation speed in a short time due to a change in the upshift side of the target gear position. That is, the clutch can be prevented from switching from a fully engaged state to a slipping engaged state during a gear upshift. As a result, the occurrence of gear shift shock during a gear upshift can be suppressed. Also, the clutch can be prevented from switching between a slipping engaged state, a fully engaged state, and again a slipping engaged state in a short period of time. Here, the predetermined rotation speed is set, for example, as the lower limit of the rotation speed range within which it is assumed that engine stall will not occur when the clutch is fully engaged, and for example, a rotation speed equal to or slightly lower than the engine idle speed is used.

[0009] In the vehicle of the present invention, the control device may set the target gear based on a shift line that is a relationship between the accelerator operation amount and the vehicle speed, and further, the control device may predict whether or not an upshift of the gear will be performed within the predetermined time based on a vehicle speed difference between the current vehicle speed at the current accelerator operation amount and the vehicle speed of the upshift shift line. In this case, the control device may predict whether or not an upshift of the gear will be performed within the predetermined time based on the vehicle speed difference and vehicle acceleration. In this way, it is possible to more appropriately predict whether or not an upshift of the gear will be performed within the predetermined time.

[0010] In the vehicle of the present invention, the control device may control the engine so that, when the clutch is in the slip engagement state, the engine rotates at the greater of the predetermined rotation speed and a rotation speed that is higher than the rotation speed of the input shaft by a second predetermined rotation speed. This makes it possible to further prevent the engine rotation speed from falling below the predetermined rotation speed when the clutch is in the slip engagement state. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram showing an outline of the configuration of a hybrid vehicle 20 as an embodiment of the present invention. [Figure 2] FIG. 2 is an explanatory diagram showing an example of a shift line diagram. [Figure 3] 4 is a flowchart showing an example of a clutch control routine executed by the HVECU 70. [Figure 4] 10 is a flowchart illustrating an example of an upshift prediction routine executed by the HVECU 70. [Figure 5] This is a time chart showing an example of the target gear Gs* and gear Gs of the transmission 40 of the embodiment, the upshift prediction flag F1, the low rotation prediction flag F2, the command to the clutch 34, the rotation speed Ne of the engine 22, the rotation speed Ni of the input shaft 41, and the target gear rotation speed Nitg. [Figure 6]10 is a time chart showing an example of the target gear Gs*, gear Gs, command to the clutch 34, rotation speed Ne of the engine 22, rotation speed Ni of the input shaft 41, and target gear rotation speed Nitg of the transmission 40 of the comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0012] Next, a mode for carrying out the present invention will be described using examples. [Example]

[0013] 1 is a diagram showing the outline of the configuration of a hybrid vehicle 20 according to one embodiment of the present invention. As shown in the figure, the hybrid vehicle 20 of the embodiment includes an engine 22, a clutch 28, a motor 30, an inverter 32, a clutch 34, a transmission 40, a high-voltage battery 60, a low-voltage battery 62, a DC / DC converter 64, and a hybrid electronic control unit (hereinafter referred to as "HVECU") 70.

[0014] The engine 22 is configured as an internal combustion engine that outputs power using fuel such as gasoline or diesel fuel from a fuel tank. A crankshaft 23 of the engine 22 is connected to a rotor of a motor 30 via a clutch 28. The operation of the engine 22 is controlled by an engine electronic control unit (hereinafter referred to as "engine ECU") 24.

[0015] The engine ECU 24 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports (not shown). Signals from various sensors required for controlling the operation of the engine 22, such as a crank angle θcr from a crank position sensor 23a that detects the rotational position of a crankshaft 23 of the engine 22, are input to the engine ECU 24 via an input port. Various control signals for controlling the operation of the engine 22 are output from the engine ECU 24 via an output port. The engine ECU 24 is connected to the HVECU 70 via a communication port. The engine ECU 24 calculates the rotation speed Ne of the engine 22 based on the crank angle θcr of the crankshaft 23 from the crank position sensor 23a.

[0016] Clutch 28 is configured as, for example, a hydraulically driven friction clutch, and connects and disconnects between crankshaft 23 of engine 22 and the rotating shaft of motor 30. Motor 30 is configured as, for example, a synchronous generator-motor. A rotor of motor 30 is connected to crankshaft 23 of engine 22 via clutch 28 and to input shaft 41 of transmission 40 via clutch 34. Inverter 32 is used to drive motor 30 and is connected to high-voltage power line 61. Motor 30 is rotationally driven by HVECU 70 controlling the switching of multiple switching elements of inverter 32. Clutch 34 is configured as, for example, a hydraulically driven friction clutch, and connects and disconnects between the rotating shaft of motor 30 and input shaft 41 of transmission 40.

[0017] The transmission 40 is configured as, for example, a four-speed automatic transmission and has an input shaft 41, an output shaft 42, multiple planetary gears, and multiple hydraulically driven friction engagement elements (clutches and brakes). The input shaft 41 is connected to the rotor of the motor 30 via the clutch 34, and the output shaft is connected to a drive shaft 46 that is connected to drive wheels 49 via a differential gear 48. Each of the multiple friction engagement elements has a hydraulic servo composed of a piston, multiple friction engagement plates (friction plates and separator plates), an oil chamber to which hydraulic oil is supplied, and the like. The transmission 40 establishes forward gears (first to fourth speeds) and reverse gears by engaging and disengaging the multiple friction engagement elements, and transmits power between the input shaft 41 and the output shaft 42. The above-mentioned clutch 28, clutch 34, and multiple friction engagement elements of the transmission 40 are operated by supplying and discharging hydraulic oil from a hydraulic control device (not shown).

[0018] High-voltage battery 60 is configured as, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery, and is connected to high-voltage power line 61 together with inverter 32. Low-voltage battery 62 is configured as, for example, a lead-acid battery having a lower rated voltage than high-voltage battery 60, and is connected to low-voltage power line 63. High-voltage battery 60 and low-voltage battery 62 are housed in the same case. DC / DC converter 64 is connected to high-voltage power line 61 and low-voltage power line 63. DC / DC converter 64 is controlled by HVECU 70 to supply power from high-voltage power line 61 to low-voltage power line 63 with the voltage stepped down.

[0019] Although not shown, the HVECU 70 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. Signals from various sensors are input to the HVECU 70 via input ports. Examples of signals input to the HVECU 70 include the rotational position θm of the rotor of the motor 30 from a rotational position sensor (e.g., a resolver) 30a that detects the rotational position of the rotor of the motor 30, the rotation speed Ni of the input shaft 41 from a rotation speed sensor 41a that detects the rotation speed of the input shaft 41 of the transmission 40, and the rotation speed No of the output shaft 42 from a rotation speed sensor 42a that detects the rotation speed of the output shaft 42 of the transmission 40. Other examples of the current Ib1 include the voltage Vb1 of the high-voltage battery 60 from a voltage sensor attached between the terminals of the high-voltage battery 60, the current Ib1 of the high-voltage battery 60 from a current sensor attached to the output terminal of the high-voltage battery 60, the voltage Vb2 of the low-voltage battery 62 from a voltage sensor 67a attached between the terminals of the low-voltage battery 62, and the current Ib2 of the low-voltage battery 62 from a current sensor attached to the output terminal of the low-voltage battery 62. Other examples of the current Ib1 include a start signal from a start switch 80 and a shift position SP from a shift position sensor 82 that detects the operating position of a shift lever 81. Other examples of the current Ib1 include an accelerator opening Acc from an accelerator pedal position sensor 84 that detects the amount of depression of an accelerator pedal 83, a brake pedal position BP from a brake pedal position sensor 86 that detects the amount of depression of a brake pedal 85, a vehicle speed V from a vehicle speed sensor 88, and a vehicle acceleration α from an acceleration sensor 89.

[0020] Various control signals are output from the HVECU 70 via an output port. Examples of signals output from the HVECU 70 include a control signal to the clutch 28, a control signal to the inverter 32, a control signal to the clutch 34, a control signal to the transmission 40, and a control signal to the DC / DC converter 64. The HVECU 70 is connected to the engine ECU 24 via a communication port. The HVECU 70 calculates the rotation speed Nm of the motor 30 based on the rotational position θm of the rotor of the motor 30 from the rotational position sensor 30a, and calculates the gear position Gs of the transmission 40 based on the engaged friction engagement elements among the multiple friction engagement elements.

[0021] The hybrid vehicle 20 of the embodiment configured as described above runs in a hybrid driving mode (HV driving) and an electric driving mode (EV driving). The HV driving mode is a mode in which the vehicle runs with the clutch 28 and the clutch 34 engaged and the engine 22 running, while the EV driving mode is a mode in which the clutch 28 is released and the clutch 34 engaged and the vehicle runs without the engine 22 running. The engagement states of the clutches 28 and 34 include not only a fully engaged state but also a slipping engaged state.

[0022] In the HV driving mode, the following HV driving control is performed by cooperative control between the HVECU 70 and the engine ECU 24. In the control of the transmission 40 in the HV driving control, a target gear Gs* of the transmission 40 is set based on the accelerator opening Acc, the vehicle speed V, and a shift map. When the gear Gs matches the target gear Gs*, the gear Gs is maintained. When the gear Gs differs from the target gear Gs*, a shift process (upshift or downshift) is performed so that the gear Gs matches the target gear Gs*. FIG. 2 is an explanatory diagram showing an example of a shift map. In the figure, solid lines indicate shift lines for upshifting, and dashed lines indicate shift lines for downshifting.

[0023] The gear shift process (upshift or downshift) is performed as follows. First, the hydraulic pressure of a disengagement element, which is one of the multiple friction engagement elements and switches from an engaged state to a disengaged state, is reduced by one stage, and stroke control of the engagement element, which switches from a disengaged state to an engaged state, is performed. The stroke control involves a fast fill (stroking the piston) to close the gap between the piston of the engagement element and the friction engagement plate, and a low-pressure standby (low-pressure standby) to maintain the hydraulic pressure of the engagement element at a relatively low standby pressure. Next, the hydraulic pressure of the disengagement element is gradually reduced while the hydraulic pressure of the engagement element is gradually increased, thereby shifting torque transmission from the disengagement element to the engagement element (torque phase). Next, the hydraulic pressure of the disengagement element is gradually reduced while the hydraulic pressure of the engagement element is gradually increased, thereby changing the rotation speed Ni of the input shaft 41 of the transmission 40 to the rotation speed corresponding to the new gear position Gs (inertia phase). When the rotation speed Ni of the input shaft 41 reaches the rotation speed corresponding to the new gear position Gs, the hydraulic pressure of the engagement element is further increased, completing the gear shift process.

[0024] In controlling the engine 22 and motor 30 in HV driving control, the required torque Tin* of the input shaft 41 of the transmission 40 is set based on the accelerator opening Acc, the vehicle speed V, and the gear position Gs of the transmission 40, and operation control of the engine 22 (intake air volume control, fuel injection control, ignition control, etc.) and control of the motor 30 (switching control of multiple switching elements of the inverter 32) are performed so that the required torque Tin* is output to the input shaft 41.

[0025] In the EV driving mode, the following EV driving control is performed by cooperative control between the HVECU 70 and the engine ECU 24. The control of the transmission 40 in the EV driving control is the same as the control of the transmission 40 in the HV driving mode. The control of the motor 30 in the EV driving control is performed by setting the required torque Tin* of the input shaft 41, as in the HV driving mode, and controlling the motor 30 so that the required torque Tin* is output to the input shaft 41.

[0026] Next, a description will be given of the operation of the hybrid vehicle 20 of this embodiment configured as described above, in particular the control of the clutch 34. Figure 3 is a flowchart showing an example of a clutch control routine executed by the HVECU 70. This routine is executed repeatedly.

[0027] When the HV driving mode clutch control routine of FIG. 3 is executed, the HVECU 70 first inputs the driving mode Md (step S100). Here, the current driving mode (HV driving mode or EV driving mode) is input as the driving mode Md. Next, it is determined whether the driving mode Md is the HV driving mode or the EV driving mode (step S110). If the driving mode Md is the EV driving mode, a full engagement command is output to the clutch 34 (step S160), and this routine ends. This full engagement command causes the clutch 34 to enter a fully engaged state or to be maintained in a fully engaged state.

[0028] When the driving mode Md is the HV driving mode in step S110, the target gear rotation speed Nitg, which is the rotation speed of the input shaft 41 corresponding to the target gear Gs* of the transmission 40, the upshift prediction flag F1, and the low rotation prediction flag F2 are input (step S120). Here, the target gear rotation speed Nitg is input as a value obtained by multiplying the rotation speed No of the output shaft 42 of the transmission 40 detected by the rotation speed sensor 42a by the gear ratio ρ at the target gear Gs*. Note that when the gear Gs of the transmission 40 and the target gear Gs* match (when gear shift processing is not in progress), the target gear rotation speed Nitg matches the rotation speed Ni of the input shaft 41 detected by the rotation speed sensor 41a.

[0029] The upshift prediction flag F1 is a flag indicating the result of a prediction as to whether an upshift of a gear in the transmission 40 will be performed within a predetermined time T1 (e.g., several seconds to approximately 10 seconds), and a value set by the upshift prediction routine of FIG. 4 is input thereto. The low rotation speed prediction flag F2 is a flag indicating the result of a prediction as to whether the rotation speed Ni of the input shaft 41 will be less than a predetermined rotation speed Ni1 after an upshift of a gear in the transmission 40, and a value set by the upshift prediction routine of FIG. 4 is input thereto. The predetermined rotation speed Ni1 is set as the lower limit of the rotation speed range within which an engine stall is not expected to occur when the clutch 34 is fully engaged in the HV driving mode (when the rotation speed of the engine 22 and the rotation speed of the input shaft 41 of the transmission 40 are made the same). For example, a rotation speed equal to or slightly lower than the idle rotation speed Nidl of the engine 22 is used. Hereinafter, the description of the clutch control routine of FIG. 3 will be interrupted and the upshift prediction routine of FIG. 4 will be described. This routine is repeatedly executed when the driving mode Md is the HV driving mode.

[0030] 4 is executed, the HVECU 70 first inputs data such as accelerator pedal position Acc, vehicle speed V, and vehicle acceleration α (step S200). Here, the accelerator pedal position Acc is input as a value detected by the accelerator pedal position sensor 84. The vehicle speed V is input as a value detected by the vehicle speed sensor 88. The vehicle acceleration α is input as a value detected by the acceleration sensor 89.

[0031] Once the data has been input in this manner, an upshift vehicle speed Vup, which is the vehicle speed on the upshift line of the transmission 40 at the current accelerator opening Acc, is set (step S210). This process can be performed by applying the current accelerator opening Acc to the shift line diagram of Figure 2. For example, when the current gear Gs is first gear, the vehicle speed V at the intersection of the current accelerator opening Acc and the upshift line from first gear to second gear on the shift line diagram of Figure 2 is set as the upshift vehicle speed Vup.

[0032] Next, the vehicle speed difference ΔV between the upshift vehicle speed Vup and the current vehicle speed V is calculated (step S220), and based on the vehicle speed difference ΔV and the vehicle acceleration α, it is predicted whether or not the transmission 40 will upshift a gear within the predetermined time T1 (steps S230, S232). This process is performed, for example, as follows: When the vehicle acceleration α is equal to or less than 0, it is predicted that the transmission 40 will not upshift a gear within the predetermined time T1. When the vehicle acceleration α is greater than the value 0, the vehicle speed difference ΔV is divided by the vehicle acceleration α to calculate the required time Trq for the vehicle speed V to reach the upshift vehicle speed Vup, and when the required time Trq is equal to or less than a predetermined time T1, it is predicted that the gear upshift of the transmission 40 will be performed within the predetermined time T1, and when the required time Trq is longer than the predetermined time T1, it is predicted that the gear upshift of the transmission 40 will not be performed within the predetermined time T1.

[0033] If it is predicted in steps S230 and S232 that an upshift of the gear of the transmission 40 will not be performed within the predetermined time T1, the upshift prediction flag F1 is set to 0 (step S240). In this case, for convenience, it is predicted that the rotation speed Ni of the input shaft 41 will not fall below the predetermined rotation speed Ni1 after the upshift of the gear of the transmission 40 (engine stall will not occur when the clutch 34 is fully engaged), the low rotation prediction flag F2 is set to 0 (step S280), and this routine ends.

[0034] If it is predicted in steps S230 and S232 that an upshift of a gear of the transmission 40 will be performed within the predetermined time T1, the upshift prediction flag F1 is set to a value of 1 (step S250), and a post-upshift input rotational speed Niupf, which is the rotational speed of the input shaft 41 when the upshift of the gear of the transmission 40 is completed, is predicted based on the upshift vehicle speed Vup and the vehicle acceleration α (step S260). Here, the processing of step S260 is performed, for example, as follows: First, a post-upshift vehicle speed Vupf, which is the vehicle speed when the upshift of the gear is completed, is predicted based on the upshift vehicle speed Vup, the vehicle acceleration α, and the time required for the upshift. Next, a post-upshift output rotational speed Noupf, which is the rotational speed of the output shaft 42 when the upshift of the gear is completed, is predicted by multiplying the post-upshift vehicle speed Vupf by a conversion coefficient kv. Then, the product of the post-upshift output rotation speed Noupf and the gear ratio ρ of the gear stage after the upshift is estimated as the post-upshift input rotation speed Niupf. The time required for the upshift is determined in advance through experiments or analysis.

[0035] Once the post-upshift input rotation speed Niupf has been predicted in this manner, the predicted post-upshift input rotation speed Niupf is compared with the above-mentioned predetermined rotation speed Ni1 (step S270). This process is to predict whether or not the rotation speed Ni of the input shaft 41 will be less than the predetermined rotation speed Ni1 after an upshift of the gear stage of the transmission 40 (if the clutch 34 is fully engaged, engine stall may occur).

[0036] If the input rotation speed Niupf after upshift is equal to or greater than the predetermined rotation speed Ni1 in step S270, it is predicted that the rotation speed Ni of the input shaft 41 will not fall below the predetermined rotation speed Ni1 after upshifting the gear of the transmission 40 (engine stall will not occur when the clutch 34 is fully engaged), and the low rotation prediction flag F2 is set to 0 (step S280), and this routine is terminated.

[0037] If the input rotation speed Niupf after upshifting is less than the predetermined rotation speed Ni1 in step S270, it is predicted that the rotation speed Ni of the input shaft 41 will be less than the predetermined rotation speed Ni1 after upshifting the gear of the transmission 40 (engine stall may occur if the clutch 34 is fully engaged), the low rotation prediction flag F2 is set to a value of 1 (step S290), and this routine is terminated.

[0038] The upshift prediction routine of Figure 4 has been described. Returning to the description of the clutch control routine of Figure 3, when the target gear speed Nitg, upshift prediction flag F1, and low rotation prediction flag F2 are input in step S120, the target gear speed Nitg is compared with the above-mentioned predetermined speed Ni1 (step S130). This process is to determine whether or not engine stall may occur if the clutch 34 is brought into a fully engaged state.

[0039] If the target gear speed Nitg is less than the predetermined speed Ni1 in step S130, it is determined that fully engaging the clutch 34 may result in engine stall, and a slip engagement command is output to the clutch 34 (step S170), followed by terminating the routine. This slip engagement command causes the clutch 34 to enter or remain in a slip engagement state. This prevents the engine speed Ne of the engine 22 from falling below the predetermined speed Ni1, thereby preventing engine stall. In this embodiment, the engine 22 and the motor 30 are controlled so that the required torque Tin* is output to the input shaft 41 while the engine 22 rotates at the greater of the predetermined speed Ni1 and a speed (Ni + ΔNi) that is higher than the speed Ni of the input shaft 41 of the transmission 40 by a predetermined speed ΔNi. By this control, the rotation speed Ne of the engine 22 can be further prevented from falling below the predetermined rotation speed Ni1, and the occurrence of engine stall can be further prevented.

[0040] If the target gear speed Nitg is equal to or greater than the predetermined speed Ni1 in step S130, it is determined that engine stall will not occur when the clutch 34 is fully engaged, and the value of the upshift prediction flag F1 is checked (step S140). If the upshift prediction flag F1 is equal to 0, that is, if it is predicted that an upshift of the gear of the transmission 40 will not occur within the predetermined time T1, a full engagement command is output to the clutch 34 (step S160), and this routine ends.

[0041] When the upshift prediction flag F1 is set to 1 in step S140, i.e., when it is predicted that an upshift of the gear of the transmission 40 will occur within the predetermined time T1, the value of the low rotation prediction flag F2 is checked (step S150). When the low rotation prediction flag F2 is set to 0, i.e., when it is predicted that the rotation speed Ni of the input shaft 41 will not become less than the predetermined rotation speed Ni1 after the gear of the transmission 40 is upshifted (when the clutch 34 is fully engaged, the engine will not stall), a full engagement command is output to the clutch 34 (step S160), and the routine ends. On the other hand, when the low rotation prediction flag F2 is set to 1, i.e., when it is predicted that the rotation speed Ni of the input shaft 41 will become less than the predetermined rotation speed Ni1 after the gear of the transmission 40 is upshifted (when the clutch 34 is fully engaged, the engine may stall), a slip engagement command is output to the clutch 34 (step S170), and the routine ends.

[0042] FIG. 5 is a time chart showing an example of the target gear Gs* and gear Gs of the transmission 40 of the embodiment, the upshift prediction flag F1, the low rotation speed prediction flag F2, a command to the clutch 34, the rotation speed Ne of the engine 22, the rotation speed Ni of the input shaft 41, and the target gear rotation speed Nitg. FIG. 6 is a time chart showing an example of the target gear Gs* and gear Gs of the transmission 40 of the comparative example, the command to the clutch 34, the rotation speed Ne of the engine 22, the rotation speed Ni of the input shaft 41, and the target gear rotation speed Nitg. In the comparative example, in the clutch control routine of FIG. 3, in the HV driving mode, the upshift prediction flag F1 and the low rotation speed prediction flag F2 are not taken into consideration, and a slip engagement command is output to the clutch 34 when the target gear rotation speed Nitg is less than a predetermined rotation speed Ni1, and a full engagement command is output to the clutch 34 when the target gear rotation speed Nitg is equal to or greater than the predetermined rotation speed Ni1. In Figures 5 and 6, when the gear Gs of the transmission 40 matches the target gear Gs* (when not upshifting) (other than times t12 to t13 in Figure 5 and other than times t22 to t23 in Figure 6), the rotation speed Ni of the input shaft 41 matches the target gear rotation speed Nitg.

[0043] In the comparative example, as shown in FIG. 6, when the target gear Gs* and gear Gs of the transmission 40 are in first gear and the target gear rotation speed Nitg increases and reaches or exceeds a predetermined rotation speed Ni1 (time t21), the command for the clutch 34 is switched from a slip engagement command to a full engagement command. Thereafter, when the target gear Gs* switches from first gear to second gear (time t22), an upshift of the gear starts. At this time, because the target gear rotation speed Nitg is less than the predetermined rotation speed Ni1, the command for the clutch 34 is switched from a full engagement command to a slip engagement command. In this case, there is a possibility that a gear shift shock will occur when the clutch 34 is switched from a full engagement state to a slip engagement state during the upshift. For example, as shown in FIG. 6, if the clutch 34 is switched from a fully engaged state to a slipping engaged state during the inertia phase (when the rotation speed Ni of the input shaft 41 is changing toward the target gear rotation speed Nitg), the effect of the inertia of the mass body (such as the engine 22 or the motor 30) on the input shaft 41 may change, causing the rotation speed Ni of the input shaft 41 to change erratically, potentially resulting in a shift shock. In addition, in the comparative example, the clutch 34 may be switched between the slipping engaged state, the fully engaged state, and the slipping engaged state again in a short period of time. Then, when the gear upshift is completed (time t23), the gear Gs coincides with the target gear Gs*. Thereafter, when the target gear Gs* of the transmission 40 is in second gear and the target gear rotation speed Nitg increases and reaches or exceeds a predetermined rotation speed Ni1 (time t24), the command for the clutch 34 is switched from a slipping engaged command to a fully engaged command.

[0044] 5, in the embodiment, when the target gear Gs* and gear Gs of the transmission 40 are in first gear, and it is predicted that an upshift of the gear will occur within a predetermined time T1, and it is also predicted that the rotation speed Ni of the input shaft 41 will be less than a predetermined rotation speed Ni1 after the gear upshift (time t10), the upshift prediction flag F1 and the low rotation prediction flag F2 are switched from the value 0 to the value 1. Then, when the upshift prediction flag F1 and the low rotation prediction flag F2 are the value 1, and the target gear rotation speed Nitg increases and reaches or exceeds the predetermined rotation speed Ni1 (time t11), the command to the clutch 34 is maintained as a slip engagement command. Thereafter, when the target gear Gs* shifts from first to second (time t12), an upshift of the gear begins, and the upshift prediction flag F1 and the low rotation prediction flag F2 are set to 0 so that an upshift of the gear (from second to third) is not predicted within the predetermined time T1. When the target gear Gs* shifts from first to second, the target gear rotation speed Nitg is less than the predetermined rotation speed Ni1, so the command for the clutch 34 is maintained as a slip engagement command. This prevents the clutch 34 from switching between a fully engaged state and a slip engagement state during the upshift, thereby preventing shift shock. It also prevents the clutch 34 from switching between a slip engagement state, a fully engaged state, and a slip engagement state in a short period of time. Then, when the upshift of the gear is completed (time t13), the gear Gs coincides with the target gear Gs*. Thereafter, when the target gear Gs* of the transmission 40 is second speed, and it is predicted that an upshift of the gear will occur within a predetermined time T1, and it is also predicted that the rotation speed Ni of the input shaft 41 will not become less than a predetermined rotation speed Ni1 after the gear upshift (time t14), the upshift prediction flag F1 is switched to value 1, and the low rotation prediction flag F2 is maintained at value 0. Then, when the upshift prediction flag F1 is value 1 and the low rotation prediction flag F2 is value 0, and the target gear rotation speed Nitg increases and reaches or exceeds the predetermined rotation speed Ni1 (time t15), the command to the clutch 34 is switched from a slip engagement command to a full engagement command.

[0045] In this embodiment, when the target gear Gs* and the gear Gs match, if the target gear rotation speed Nitg changes from less than the predetermined rotation speed Ni1 to equal to or greater than the predetermined rotation speed Ni1 (times t11 and t15), and the upshift prediction flag F1 and the low rotation prediction flag F2 are set to value 1 (time t11), the command to the clutch 34 is maintained as a slip engagement command, and if the upshift prediction flag F1 is set to value 0 or if the upshift prediction flag F1 is set to value 1 and the low rotation prediction flag F2 is set to value 0 (time t15), the command to the clutch 34 is switched to a full engagement command. Therefore, it is necessary to set the predetermined time T1 so that it is possible to predict that an upshift of the gear will occur within the predetermined time T1 before the target gear rotation speed Nitg reaches or exceeds the predetermined rotation speed Ni1. Specifically, it is necessary to set the predetermined time T1.

[0046] In the hybrid vehicle 20 of the embodiment described above, when the target gear rotation speed Nitg, which is the rotation speed of the input shaft 41 corresponding to the target gear Gs* of the transmission 40, is less than the predetermined rotation speed Ni1, a slip engagement command is output to the clutch 34. Furthermore, when the target gear rotation speed Nitg is equal to or greater than the predetermined rotation speed Ni1, and it is predicted that the gear upshift of the transmission 40 will not be performed within the predetermined time T1, or when it is predicted that the gear upshift will be performed within the predetermined time T1 and the rotation speed Ni of the input shaft 41 will not become less than the predetermined rotation speed Ni1 after the gear upshift, a full engagement command is output to the clutch 34. Furthermore, when the target gear rotation speed Nitg is equal to or greater than the predetermined rotation speed Ni1, and it is predicted that the gear upshift will be performed within the predetermined time T1 and the rotation speed Ni of the input shaft 41 will become less than the predetermined rotation speed Ni1 after the gear upshift, a slip engagement command is output to the clutch 34. This prevents the clutch 34 from being switched from a slip-engagement state to a fully engaged state when the target gear rotation speed Nitg rises from less than the predetermined rotation speed Ni1 to equal to or greater than the predetermined rotation speed Ni1 before a gear upshift, and then, in a short time, a change in the target gear Gs* on the upshift side (e.g., a change from first gear to second gear) causes the target gear rotation speed Nitg to fall below the predetermined rotation speed Ni1, causing the clutch 34 to be switched back to the slip-engagement state. In other words, the clutch can be prevented from being switched from a fully engaged state to a slip-engagement state during a gear upshift. As a result, shift shock can be prevented from occurring during a gear upshift. Furthermore, the clutch 34 can be prevented from being switched between the slip-engagement state, the fully engaged state, and the slip-engagement state again in a short time.

[0047] In the hybrid vehicle 20 of the embodiment, it is predicted whether or not the transmission 40 will upshift a gear within the predetermined time T1 based on the vehicle speed difference ΔV and the vehicle acceleration α. ​​However, it may also be possible to predict whether or not the transmission 40 will upshift a gear within the predetermined time T1 based only on the vehicle speed difference ΔV without considering the vehicle acceleration α. ​​In this case, when the vehicle speed difference ΔV is equal to or smaller than a threshold value ΔVref, it may be predicted that the transmission 40 will upshift a gear within the predetermined time T1, and when the vehicle speed difference ΔV is greater than the threshold value ΔVref, it may be predicted that the transmission 40 will not upshift a gear within the predetermined time T1. Here, the threshold value ΔVref is, for example, a few km / h to 10 km / h.

[0048] In the hybrid vehicle 20 of the embodiment, the transmission 40 is configured as a four-speed automatic transmission. However, the transmission 40 may be configured as a three-speed, five-speed, six-speed, or other automatic transmission.

[0049] The hybrid vehicle 20 of the embodiment is equipped with the engine ECU 24 and the HVECU 70. However, these may be configured as a single electronic control unit.

[0050] In the embodiment, the hybrid vehicle 20 is configured to include an engine 22, a clutch 28, a motor 30, an inverter 32, a clutch 34, a transmission 40, a high-voltage battery 60, a low-voltage battery 62, and a DC / DC converter 64. However, the hybrid vehicle 20 may have a configuration in which the clutch 28, the motor 30, the inverter 32, the high-voltage battery 60, and the DC / DC converter 64 are excluded from the hardware configuration.

[0051] The correspondence between the main elements of the embodiment and the main elements of the invention described in the "Means for Solving the Problem" section will be explained below. In the embodiment, the engine 22 corresponds to the "engine," the transmission 40 corresponds to the "transmission," the clutch 34 corresponds to the "clutch," and the HVECU 70 and the engine ECU 24 correspond to the "controller."

[0052] The correspondence between the main elements of the Examples and the main elements of the invention described in the "Means for Solving the Problem" section does not limit the elements of the invention described in the "Means for Solving the Problem" section, since the Examples are examples for specifically explaining the mode for implementing the invention described in the "Means for Solving the Problem" section. In other words, the interpretation of the invention described in the "Means for Solving the Problem" section should be based on the description in that section, and the Examples are merely specific examples of the invention described in the "Means for Solving the Problem" section.

[0053] The above describes the form for carrying out the present invention using examples, but the present invention is not limited to these examples in any way, and it goes without saying that the present invention can be carried out in various forms within the scope that does not deviate from the gist of the present invention. [Industrial Applicability]

[0054] The present invention can be used in the vehicle manufacturing industry and the like. [Explanation of symbols]

[0055] 20 hybrid vehicle, 22 engine, 23 crankshaft, 23a crank position sensor, 24 engine ECU, 28 clutch, 30 motor, 30a rotational position sensor, 32 inverter, 34 clutch, 40 transmission, 41 input shaft, 41a rotation speed sensor, 42 output shaft, 42a rotation speed sensor, 46 drive shaft, 48 differential gear, 49 drive wheels, 60 high-voltage battery, 61 high-voltage side power line, 62 low-voltage battery, 63 low-voltage side power line, 64 DC / DC converter, 67a voltage sensor, 70 HVECU, 80 start switch, 81 shift lever, 82 shift position sensor, 83 accelerator pedal, 84 accelerator pedal position sensor, 85 brake pedal, 86 brake pedal position sensor, 88 vehicle speed sensor, 89 acceleration sensor.

Claims

1. The engine and a transmission connected to the drive wheels; a clutch provided between the engine and the transmission; a control device that controls the transmission so that the gear position becomes a target gear position based on an accelerator operation amount and a vehicle speed, and that brings the clutch into a fully engaged state when a target gear position rotation speed, which is the rotation speed of an input shaft of the transmission corresponding to the target gear position, is equal to or greater than a predetermined rotation speed, and brings the clutch into a slipping engaged state when the target gear position rotation speed is less than the predetermined rotation speed; A vehicle comprising: When the target gear speed is equal to or higher than the predetermined speed, the control device predicts that an upshift of the gear will be performed within a predetermined time and, when it predicts that the rotation speed of the input shaft will be less than the predetermined speed after the upshift, brings the clutch into a slip engagement state. vehicle.

2. 2. The vehicle according to claim 1, the control device sets the target gear position based on a shift line that is a relationship between the accelerator operation amount and the vehicle speed, Furthermore, the control device predicts whether or not the gear upshift will be performed within the predetermined time based on a vehicle speed difference between a current vehicle speed at a current accelerator operation amount and a vehicle speed on the shift line for upshifting. vehicle.

3. 3. The vehicle according to claim 2, the control device predicts whether or not an upshift of the gear position will be performed within the predetermined time based on the vehicle speed difference and the vehicle acceleration. vehicle.

Images