The control method for a constant speed running of a vehicle performs a vehicle speed control for downshifting the gear position of the automatic transmission when the acceleration/deceleration of the vehicle is larger than the determination value during the constant speed running control. In the control method, the automatic transmission includes a plurality of gear positions that can be downshifted during the constant speed running control, and among the plurality of gear positions, the determination value between the gear positions having a relatively large difference in the gear ratio between the gear positions is set to be larger than the determination value between the gear positions having a relatively small difference in the gear ratio between the gear positions.

A power transmission device includes a torque converter device, a first hydraulic pump, a first oil channel, a second oil channel, a third oil channel, a second pressure control valve, and a controller. The torque converter device has a torque converter and a lock-up clutch. The first oil channel supplies hydraulic fluid from the first hydraulic pump to the torque converter. The second oil channel drains hydraulic fluid from the torque converter. The third oil channel communicates with the first oil channel and the second oil channel. The second pressure control valve is disposed in the third oil channel. The controller sets the second pressure control valve to an open state when the lock-up clutch is in an engaged state.

A transmission structure of the present invention changes capacity of pump body so that vehicle speed detected by vehicle speed sensor increases and reduces according to speed-increasing and speed-reducing operations of speed-change operating member while fixing capacity of motor body at a low-speed motor capacity when the vehicle speed is equal to or lower than a switching speed that is realized by setting motor body to the low-speed motor capacity and setting the pump body to a predetermined pump switching capacity, and changes capacity of motor body so that vehicle speed increases and reduces in accordance with speed-increasing and speed-reducing operations of speed-change operating member while fixing capacity of the pump body at the pump switching capacity when vehicle speed is higher than the switching speed.

A transmission structure of the present invention changes capacity of pump body so that vehicle speed detected by vehicle speed sensor increases and reduces according to speed-increasing and speed-reducing operations of speed-change operating member while fixing capacity of motor body at a low-speed motor capacity when the vehicle speed is equal to or lower than a switching speed that is realized by setting motor body to the low-speed motor capacity and setting the pump body to a predetermined pump switching capacity, and changes capacity of motor body so that vehicle speed increases and reduces in accordance with speed-increasing and speed-reducing operations of speed-change operating member while fixing capacity of the pump body at the pump switching capacity when vehicle speed is higher than the switching speed.

Disclosed are a method and device for controlling the state switching of a fluid torque converter, a vehicle and a storage medium, the method including: obtaining a target instruction when the torque converter of the vehicle is in a locked state, the target instruction triggering a change in the torque transmission direction of a transmission system of the vehicle; obtaining a state parameter, and determining whether the current vehicle is in a target operating condition according to the state parameter; and if the current vehicle is in the target operating condition, switching the fluid torque converter to an open state, and switching the torque converter back to the locked state after maintaining the open state for a preset period of time.

Disclosed are a method and device for controlling the state switching of a fluid torque converter, a vehicle and a storage medium, the method including: obtaining a target instruction when the torque converter of the vehicle is in a locked state, the target instruction triggering a change in the torque transmission direction of a transmission system of the vehicle; obtaining a state parameter, and determining whether the current vehicle is in a target operating condition according to the state parameter; and if the current vehicle is in the target operating condition, switching the fluid torque converter to an open state, and switching the torque converter back to the locked state after maintaining the open state for a preset period of time.

A control device for an automatic transmission in a vehicle with a constant speed travel mode includes: a determination section that determines whether the vehicle is traveling on a slope road; a slope adaptation control section that implements a first transmission shift control if not traveling on a slope road and, if traveling on a slope road, implements a second transmission shift control for selecting a transmission shift position of a lower speed than case of not traveling on a slope road; a delaying section that, upon switching from the second transmission shift control to the first transmission shift control, implements an upshift delay control for performing upshift one by one at a predetermined time interval; and a setting section that, in case of traveling at the constant speed travel mode, sets the time interval shorter in comparison with case of traveling not at the constant speed travel mode.

A control device for an automatic transmission in a vehicle with a constant speed travel mode includes: a determination section that determines whether the vehicle is traveling on a slope road; a slope adaptation control section that implements a first transmission shift control if not traveling on a slope road and, if traveling on a slope road, implements a second transmission shift control for selecting a transmission shift position of a lower speed than case of not traveling on a slope road; a delaying section that, upon switching from the second transmission shift control to the first transmission shift control, implements an upshift delay control for performing upshift one by one at a predetermined time interval; and a setting section that, in case of traveling at the constant speed travel mode, sets the time interval shorter in comparison with case of traveling not at the constant speed travel mode.

Various methods and systems are provided for a shift assembly for a vehicle transmission. In one example, a shift assembly for a transmission includes a first barrel cam including a first cam track; a second barrel cam arranged coaxially with the first barrel cam and including a second cam track; a first motor configured to drive the first barrel cam independent of the second barrel cam; and a second motor configured to drive the second barrel cam independent of the first barrel cam.

An oil pressure estimation device for calculating an estimated differential pressure that is an estimated value of a differential pressure between two oil chambers generated in a torque converter including the two oil chambers and a lockup clutch includes a storage device and an execution device. The storage device stores mapping data defining a mapping, the mapping outputting as an output variable an estimated differential pressure variable indicating the estimated differential pressure, in response to input of an input variable, and the mapping having been trained by machine learning. The mapping includes an instruction differential pressure variable indicating the instruction differential pressure as one of a plurality of the input variables. The execution device executes an acquisition process of acquiring a value of the input variable and a calculation process of inputting the value of the input variable into the mapping to calculate a value of the output variable.