JP2019074056A - Vehicular controller and control method - Google Patents

Abstract

To effectively engage a lock-up clutch upon letting out a clutch.SOLUTION: A controller 100 of a vehicle 1 is configured to transmit rotational power of a drive source 2 to a transmission 80 from a fluid joint 10 including a lock-up clutch 25 via a clutch device 70. The controller is configured to, when shift control is executed in a state where a lock-up output rotational frequency is larger than a lock-up input rotational frequency and the lock-up clutch 25 is in a cut-off state, execute rotational frequency control of controlling the drive source 2 so that a rotational frequency input from the drive source 2 to the lock-up clutch 25 is kept so as to be equal to or larger than a rotational frequency in start of shift control.SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to a control device and control method of a vehicle.

  Conventionally, in vehicles and the like, a power transmission device in which a fluid coupling (including a torque converter), a clutch device, a transmission, and the like are disposed in order on the output side of a power source has been widely put to practical use. 2).

  Generally, this type of fluid coupling includes a front cover and a lockup clutch that includes a piston. The lockup clutch is configured to be engaged by releasing the hydraulic pressure from the working pressure chamber between the front cover and the piston.

JP, 2016-142321, A Japanese Patent Application Laid-Open No. 09-004693

  By the way, in the above-mentioned fluid coupling, if the number of rotations on the input side is not higher than the number of rotations on the output side, the lockup clutch tends not to be engaged or difficult to be engaged. Therefore, for example, when the rotational speed of the input side of the lockup clutch is lower than the rotational speed of the output side, the lockup clutch is engaged, for example, when the transmission shifts while the transmission shifts while the vehicle makes inertia travel on a downhill There is a problem that it becomes difficult to effectively utilize the braking force of the exhaust brake etc. by becoming difficult to do.

  The technique of the present disclosure aims to effectively engage the lockup clutch when the clutch is disengaged due to a shift change of the transmission.

  The device of the present disclosure is a control device of a vehicle equipped with a power transmission device in which rotational power of a power source is transmitted from a fluid coupling including a lock-up clutch to a transmission via a clutch device. Based on at least the vehicle speed, an input rotation speed acquiring unit that acquires an input rotation speed, an output rotation speed acquiring unit that acquires an output rotation speed of the lockup clutch, and a vehicle speed acquiring unit that acquires the vehicle speed of the vehicle. First control means for performing shift control to shift the transmission by switching the clutch device from connection to disconnection, the output rotational speed is higher than the input rotational speed, and the lockup clutch is disconnected When the first control means implements the shift control in the state of (c), the number of revolutions input from the power source to the lockup clutch is A second control means for performing a rotational speed control for controlling the driving of said power source so as to be maintained in the serial shift control at the start of the above rotational speed, and comprising: a.

  Further, the second control means may carry out the rotational speed control when the first control means implements the shift control in a state where the vehicle speed is increasing while the vehicle is traveling by inertia. preferable.

  Preferably, the second control means ends the rotational speed control when the input rotational speed matches the output rotational speed and the lockup clutch is engaged after the start of the rotational speed control.

  The transmission control apparatus further comprises transmission input rotational speed acquiring means for acquiring the input rotational speed of the transmission, and the second control means is configured to output the rotational speed after the start of the rotational speed control with the transmission input rotational speed. It is preferable that the rotational speed control be ended when the clutch device comes into contact by coincidence.

  Further, the lockup clutch includes a front cover provided integrally rotatably with an output shaft of the power source, and a piston defining an operating pressure chamber between the front cover and the front cover. It may be connected by releasing it.

  A method according to the present disclosure is a control method of a vehicle equipped with a power transmission device, wherein a rotational power of a power source is transmitted from a fluid coupling including a lockup clutch to a transmission through a clutch device. When the shift control is performed to shift the transmission by switching the clutch device from the on state to the off state with the output rotation speed being higher than the input rotation speed and the lockup clutch being disengaged, The driving of the power source is controlled so as to maintain the number of rotations input from the power source to the lockup clutch at or above that at the start of the shift control.

  According to the technology of the present disclosure, the lockup clutch can be effectively engaged when the clutch is disengaged due to a shift change of the transmission.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows an example of the power transmission device mounted in the vehicle which concerns on this embodiment. It is a timing chart figure explaining processing contents of rotation number maintenance control concerning this embodiment. It is a flowchart figure explaining rotation speed maintenance control concerning this embodiment.

  Hereinafter, based on an accompanying drawing, a control device and control method of a vehicle concerning this embodiment are explained. The same parts are given the same reference numerals, and their names and functions are also the same. Therefore, detailed description about them will not be repeated.

  FIG. 1 is a schematic view showing an example of a power transmission device mounted on a vehicle 1 according to the present embodiment. An engine 2 is mounted on the vehicle 1 as an example of a power source. A fluid coupling (for example, a torque converter) 10 is connected to the crankshaft 3 of the engine 2. A transmission 80 is connected to the fluid coupling 10 via a clutch device 70.

  The fluid coupling 10 mainly includes a pump 12, a turbine 13, an output shaft 20, a turbine hub 21, a front cover 14 constituting a lockup clutch 25, and a piston 22.

  The front cover 14 is a cylindrical member whose front side is closed and whose rear side is open. The front cover 14 is provided on the crankshaft 3 so as to be integrally rotatable, and a driving force from the engine 2 is input to the front cover 14 via the crankshaft 3.

  The front end side outer peripheral edge of the pump 12 is joined to the rear end side outer peripheral edge of the front cover 14 by, for example, welding or the like. The pump 12 is provided rotatably on the output shaft 20. The space surrounded by the front cover 14 and the pump 12 is filled with hydraulic oil.

  The turbine hub 21 is fixed to the output shaft 20 so as to be integrally rotatable. The turbine 13 is disposed to face the pump 12, and the inner peripheral side of the turbine 13 is fixed to the output shaft 20 via the turbine hub 21 so as to be integrally rotatable. The turbine 13 receives the driving force transmitted from the engine 2 to the pump 12 via the crankshaft 3 and the front cover 14 via the hydraulic fluid and transmits it to the output shaft 20.

  The piston 22 is disposed to face the rear side surface of the front cover 14. On the front side surface of the outer peripheral portion of the piston 22, a clutch fading 23 as an example of a friction material is mounted. Also, the piston 22 is fixed to the turbine hub 21 via the damper mechanism 24.

  The damper mechanism portion 24 acts to reduce torque fluctuation due to an impact when the piston 22 engages with the front cover 14 and torque fluctuation etc. when the front cover 14 and the piston 22 are in contact with each other. .

  The piston 22 is movable in the axial direction of the output shaft 20, and moves toward the front cover 14 to bring the clutch fading 23 into contact with the rear side surface of the front cover 14 to mechanically engage with the front cover 14 It is possible to With such a configuration, the piston 22 and the front cover 14 constitute a so-called lockup clutch 25.

  The piston 22 divides a space surrounded by the front cover 14 and the pump 12 into a first operating pressure chamber 29 and a second operating pressure chamber 30. The first hydraulic pressure chamber 29 can be supplied and drained with hydraulic fluid by a hydraulic oil circuit (not shown), and the second hydraulic pressure chamber 30 is operated by a hydraulic oil circuit (not shown) It is possible to supply and discharge oil.

  When the hydraulic pressure on the first working pressure chamber 29 side is higher than the hydraulic pressure on the second working pressure chamber 30 side, the piston 22 moves in a direction away from the front cover 14 and the lockup clutch 25 is disengaged ( Locked up). On the other hand, when the hydraulic pressure on the second working pressure chamber 30 side is higher than the hydraulic pressure on the first working pressure chamber 29 side, the piston 22 moves in the direction approaching the front cover 14 and the lockup clutch 25 slips. The state (half clutch state) or the engagement state (lock-up engagement state) is established.

  The clutch device 70 is, for example, a wet multi-plate clutch, and includes a plurality of clutch plates 72. The clutch device 70 has the clutch drum 71 on the input side connected to the output shaft 20 of the torque converter 10, and the clutch hub 73 on the output side connected to the input shaft 82 of the transmission 80. Connect and close the power transmission with the machine 80. The clutch device 70 may be another clutch device such as a dry single disc clutch as long as it is a speed change clutch.

  The transmission 80 is, for example, a mechanical automatic transmission (AMT), and mainly includes an input shaft 82, an output shaft 83, a countershaft 84, and a plurality of transmission gear trains 85 provided on these shafts 82 to 84, and A synchromesh mechanism 86 is provided. The output shaft 83 is connected to the left and right drive wheels via a propeller shaft, a differential gear, etc. (not shown).

  The engine speed sensor 90 is an example of the input speed acquisition means of the present invention, and acquires the engine speed NE. The turbine rotational speed sensor 91 is an example of the output rotational speed acquisition means of the present invention, and acquires the rotational speed of the clutch drum 71 (hereinafter referred to as a turbine rotational speed NT). The transmission input rotational speed sensor 92 is an example of the transmission input rotational speed acquisition means of the present invention, and acquires the input rotational speed of the transmission 80 (hereinafter referred to as the input shaft rotational speed NI). The vehicle speed sensor 93 acquires the vehicle speed V from the output rotational speed of the transmission 80. The accelerator opening degree sensor 94 acquires an accelerator opening degree AC (or a fuel injection instruction value Q) according to the depression amount of the accelerator pedal (not shown). The sensor values of these various sensors 90 to 94 are output to the electrically connected electronic control unit 100.

  The electronic control unit 100 performs various controls of the vehicle 1 and includes a known CPU, ROM, RAM, input port, output port, and the like. Further, the electronic control unit 100 includes the transmission control unit 110 and the engine control unit 120 as a part of functional elements. Although each of these functional elements is described as being included in the electronic control unit 100 which is one-piece hardware, these may be provided in separate hardware.

  The shift control unit 110 is an example of the first control means of the present invention, and is an automatic shift that automatically shifts up or down the transmission 80 based on the operating state of the engine 2 or the traveling state of the vehicle 1 or the like. Implement control. Specifically, the memory of the electronic control unit 100 stores, for example, a shift change map 130 that is referenced based on the vehicle speed V and the accelerator opening degree AC. In the shift change map 130, a plurality of shift change lines L corresponding to each gear of the transmission 80 are set. For example, when the traveling state of the vehicle 1 according to the sensor value of the vehicle speed sensor 93 moves from point A on the shift change map 130 to point B across the shift change line L, the shift control unit 110 At the same time, the synchromesh mechanism 86 is operated to execute upshift control to shift the gear train 85 to the gear on the high speed side. The shift-up shift control is ended by switching the clutch device 70 from disconnection to contact when the shift gear train 85 at the shift-up destination is synchronously coupled (geared in) by the synchromesh mechanism 86. Note that the shift change map 130 does not necessarily have to be graphical, and may be stored as numerical data. Further, the processing contents at the time of downshifting are substantially the same as those at the time of upshifting, and thus detailed description will be omitted.

  The engine control unit 120 is an example of the second control means of the present invention, and performs engine control to control the fuel injection amount of the injector (not shown) of the engine 2 according to the depression amount of the accelerator pedal by the driver. . Further, even when the driver does not depress the accelerator pedal (accelerator opening degree AC is substantially zero), engine control unit 120 causes shift control unit 110 to perform inertia travel when vehicle 1 travels downhill or the like. When the shift up control is started, the engine speed maintenance control is performed to maintain (or slightly increase) the engine speed NE at the start of the shift up control. Hereinafter, details of the rotation speed maintenance control will be described.

  FIG. 2 is a timing chart diagram for explaining the processing content of the rotation speed maintenance control. In the illustrated example, the upshift from the second gear to the third gear is shown, but it is possible to shift to the other gear such as the first gear to the second gear, or the third gear to the fourth gear, etc. The same processing is performed at the time of shift-up, so the description will be omitted.

  In FIG. 2, time t0 to t1 indicates, for example, a state in which the vehicle 1 is coasting downhill while being in geared to the second gear. At time t0 to t1, the vehicle speed V gradually increases due to the inertia running of the vehicle 1. Similarly, the turbine rotational speed NT and the input shaft rotational speed NI are gradually increased by the power transmitted from the drive wheels through the clutch device 70. During this time, the engine speed NE also gradually rises due to the drag of the fluid coupling 10.

  When the vehicle speed V exceeds the threshold (the shift line L of the shift change map 130 shown in FIG. 1) at time t1, the shift control unit 110 starts shift-up control from the second gear to the third gear. That is, the clutch device 70 is switched from being connected to being disconnected, and a gear disengaging operation to make the synchromesh mechanism 86 of the second gear stage neutral is started. Furthermore, while the hydraulic fluid is drained from the first hydraulic pressure chamber 29 of the fluid coupling 10, the engagement (lockup clutch ON) of the lockup clutch for supplying the hydraulic fluid to the second hydraulic pressure chamber 30 is started.

The engine control unit 120 sets the engine speed NE input from the engine speed sensor 90 to the target speed NE _Tag at time t1 at the start of upshift control, and thereafter, the engine speed NE is the target speed. Start rotation speed maintenance control to maintain (or slightly increase) the number NE _Tag . The fuel injection instruction value output to the injector of the engine 2 at the time of rotation speed maintenance control may output a predetermined injection amount instruction value previously set according to each target rotation speed NE _Tag , or an engine rotation speed sensor The feedback control may be performed based on the difference between the actual engine rotational speed NE _Act and the target rotational speed NE _Tag obtained by 90.

When the gear shifting operation of the second gear is started at time t1, the coupling between the second gear gear 85 and the output shaft 83 is released, whereby the input shaft rotational speed NI gradually decreases. . Similarly, as the clutch device 70 is disengaged, the turbine speed NT also gradually decreases. During this time, the engine speed NE is maintained at the target speed NE _Tag by the speed maintenance control.

  When the turbine rotational speed NT becomes lower than the engine rotational speed NE at time t2, the rotational speed of the front cover 14 on the input side of the fluid coupling 10 becomes higher than the rotational speed of the turbine 13 on the output side. 22 starts to move to the front cover 14 side. That is, when the engine speed maintenance control is not performed, as indicated by the broken line L1, the engine speed NE is lower than the turbine speed NT, so that the lockup clutch 25 becomes difficult to engage. However, by making the engine rotational speed NE (the rotational speed of the front cover 14) higher than the turbine rotational speed NT by rotational speed maintenance control, the piston 22 can be easily moved to the front cover 14 side, and the lockup clutch It becomes possible to secure 25 firmly.

  At time t3, gear-in operation of the third gear is started, and in accordance with this, when a synchronous load is generated in the synchromesh mechanism 86, the input shaft rotational speed NI gradually starts to rise due to power transmission from the drive wheels. Furthermore, at time t4, when the clutch device 70 is in the half clutch state, the turbine rotational speed NT also starts to gradually increase thereafter. Thereafter, when the turbine rotational speed NT matches the engine rotational speed NE and the lockup engagement state is established, and the clutch device 70 is completely engaged from the half clutch state, shift up control to the third gear is ended at time t5. . When the upshift control to the third gear is completed, the engine speed NE, the turbine speed NT, and the input shaft speed NI increase at substantially the same speed as the vehicle speed V increases. Dashed lines L2 and L3 indicate the transition of the turbine rotation speed NT and the input shaft rotation speed NI when the rotation speed maintenance control is not performed.

  The rotational speed maintenance control started at time t1 is at the time of lockup engagement where the turbine rotational speed NT matches the engine rotational speed NE, the end of shift up control in which the clutch device 70 is completely engaged, or from time t1. It may be ended when any condition is satisfied when the elapsed time reaches a predetermined threshold time.

  Next, the flow of the rotation speed maintenance control according to the present embodiment will be described based on FIG.

  In step S100, it is determined whether or not the vehicle 1 is in an inertia running state in which the vehicle 1 travels on a downhill or the like with inertia. If it is judged whether the accelerator opening degree acquired by the accelerator opening degree sensor 94 is substantially zero and the vehicle speed V acquired by the vehicle speed sensor 93 is increasing, whether it is in the inertia running state or not Good. If the determination is affirmative, the present control proceeds to step S110.

  In step S110, it is determined whether or not the upshift control has been started because the vehicle speed V has exceeded the threshold. When upshift control is started, the present control proceeds to step S120 in order to carry out rotation speed maintenance control.

In step S120, engine speed maintenance control is started to maintain the engine speed NE at the start of the upshift control (target engine speed NE _Tag ).

  In step S130, it is determined whether the termination condition of the rotation speed maintenance control is satisfied. As termination conditions, complete engagement of the lockup clutch 25 in which the turbine rotational speed NT matches the engine rotational speed NE, complete engagement of the clutch device 70 in which the turbine rotational speed NT matches the input shaft rotational speed NI, or rotation speed maintenance The determination may be made on the condition that any elapsed time from the start of control reaches a predetermined threshold time.

  If the end condition is satisfied in step S130, the process proceeds to step S140 and the rotation speed maintenance control is ended. That is, if the vehicle 1 is still coasting (the accelerator opening is zero), the fuel injection of the engine 2 is stopped, and if the vehicle 1 is reaccelerating, the fuel injection amount according to depression of the accelerator pedal etc. This control is returned by switching to normal engine control to control.

  According to the present embodiment described above in detail, the transmission 80 is in the state where the output side rotational speed of the fluid coupling 10 is higher than the input side rotational speed and the lockup clutch 25 is disengaged during coasting of the vehicle 1. Is shifted up, the engine speed maintenance control is performed to maintain the engine speed NE at the start of the upshift control. As a result, the engine rotational speed NE becomes higher than the turbine rotational speed NT at the time of upshift control, and the piston 22 can be easily moved to the front cover 14 side, and the lockup clutch 25 can be reliably engaged. . In addition, since the lockup clutch 25 is securely engaged, the braking force of the auxiliary brake such as the exhaust brake can be effectively used.

  The present invention is not limited to the embodiments described above, and can be appropriately modified and implemented without departing from the spirit of the present invention.

  For example, although it has been described that the rotation speed maintenance control is performed when the transmission 80 is shifted up when the vehicle 1 travels downward on the downhill, the output side rotation speed of the fluid coupling 10 is the input side rotation You may implement, when the shift change of the transmission 80 is carried out in the state higher than a number.

  The fluid coupling 10 is not limited to the torque converter, and any other pressure converter than the torque converter may be used as long as the lockup clutch 25 is disengaged by the differential pressure between the first working pressure chamber 29 and the second working pressure chamber 30. It may be another fluid coupling.

  Further, although the vehicle 1 has been described as including the engine 2 as a power source, it may be a hybrid vehicle or the like including a traveling motor.

Reference Signs List 1 vehicle 2 engine 10 fluid coupling 12 pump 13 turbine 14 front cover 22 piston 25 lockup clutch 70 clutch device 80 transmission 90 engine rotational speed sensor 91 turbine rotational speed sensor 92 transmission input rotational speed sensor 93 vehicle speed sensor 94 accelerator opening degree Sensor 100 Electronic control unit 110 Transmission control unit 120 Engine control unit

Claims (6)

A control device for a vehicle equipped with a power transmission system in which rotational power of a power source is transmitted from a fluid coupling including a lockup clutch to a transmission through a clutch device,
Input rotation number acquisition means for acquiring the input rotation number of the lockup clutch;
An output rotational speed acquiring unit that acquires an output rotational speed of the lockup clutch;
Vehicle speed acquisition means for acquiring the vehicle speed of the vehicle;
First control means for switching the clutch device from contact to disconnection based on at least the vehicle speed and performing shift control to shift the transmission;
When the first control means implements the shift control while the output rotational speed is higher than the input rotational speed and the lockup clutch is disengaged, the power is input from the power source to the lockup clutch Control means for performing rotation speed control for controlling driving of the power source such that the required rotation speed is maintained at or above the rotation speed at the start of the shift control. apparatus. The second control means executes the rotational speed control when the first control means implements the shift control in a state in which the vehicle speed is increasing while the vehicle is coasting. Control device for a vehicle. The second control means ends the rotation speed control when the input rotation speed becomes equal to the output rotation speed after the start of the rotation speed control and the lockup clutch is engaged. Control device for a vehicle. It further comprises transmission input rotational speed acquisition means for acquiring the input rotational speed of the transmission.
The second control means ends the rotation speed control when the output rotation speed becomes equal to the transmission input rotation speed after the start of the rotation speed control and the clutch device comes into contact. The control device of a vehicle according to claim 1. The lockup clutch includes a front cover provided integrally rotatably with an output shaft of the power source, and a piston defining an operating pressure chamber between the front cover and the front cover, and releasing oil pressure from the operating pressure chamber The control device for a vehicle according to any one of claims 1 to 4, which is in close contact with each other. A control method of a vehicle equipped with a power transmission device, wherein a rotational power of a power source is transmitted from a fluid coupling including a lockup clutch to a transmission through a clutch device,
In the state where the output rotational speed of the lock-up clutch is higher than the input rotational speed and the lock-up clutch is disengaged, shift control is performed to shift the transmission by shifting the clutch device from the on state to the off state. And controlling the drive of the power source to maintain the number of rotations input from the power source to the lockup clutch at or above the speed at the start of the shift control. .

Images