The disclosure provides a control method, a control device for vehicular automatic transmission, and a recording medium. The control device includes an ON/OFF control solenoid controlling LC to either ON or OFF, and an LC pressure control linear solenoid controlling LC pressure between a released state and a fully engaged state. The control device acquires, when an accelerator pedal opening of a vehicle is on a deceleration side in a fully closed state, a torque converter slip ratio when the ON/OFF control solenoid maintains ON for a predetermined time period and the LC pressure control linear solenoid is controlled such that the LC pressure is OFF, and determines whether or not the second solenoid has a high-pressure fixation failure according to whether or not the slip ratio is within a predetermined range from a slip reference value.

The controller starts an output of an engagement instruction of the lockup clutch when a vehicle speed becomes a lockup start vehicle speed under a state where the lockup clutch is disengaged. When the vehicle speed, which is obtained a predetermined time after the output of the engagement instruction is started due to the vehicle speed becoming the lockup start vehicle speed, has reached a predetermined vehicle speed, the controller continues the output of the engagement instruction. When the vehicle speed has not reached the predetermined vehicle speed, the controller stops the output of the engagement instruction and restarts the output of the engagement instruction when the vehicle speed reaches a lockup restart vehicle speed which is set to a vehicle speed higher than the lockup start vehicle speed while the output is stopped.

In one aspect, a control method and a control apparatus are provided for protecting a damper clutch of a vehicle. In one aspect, the control method of protecting the damper clutch of the vehicle includes determining whether a vehicle state satisfies a condition for operating a damper clutch protection logic, calculating a slip power in real time on the basis of a turbine speed of a torque converter, an engine speed, a capacity coefficient of the torque converter, a clutch torque, and a hydraulic torque when the condition for operating the damper clutch protection logic is satisfied, determining whether a repetitive tip-in/tip-out that is intentionally performed occurs or not on the basis of a change in the slip power that is calculated in real time for a set time, and operating the damper clutch protection logic for restraining a slip of the damper clutch when there is the repetitive tip-in/tip-out that is intentionally performed.

A torque convertor and direct drive unit arrangement and operating methods are provided herein. In one example, a prime mover may be configured to be coupled to a transmission via one of a torque convertor and a direct drive unit, the direct drive unit including a higher range clutch and a lower range clutch.

A control device controls a lockup clutch interposed between an engine and an automatic transmission mechanism of a vehicle. The control device includes a control part supplying hydraulic pressure to the lockup clutch and controlling differential pressure of the lockup clutch. The control part supplies the hydraulic pressure to the lockup clutch so that the differential pressure is lower than a reference differential pressure in a disengaged state of the lockup clutch. In a case of shifting the lockup clutch from the disengaged state to an engaged state, the control part supplies the hydraulic pressure to the lockup clutch so that the differential pressure increases as a filling ratio of an oil passage of the lockup clutch decreases. The reference differential pressure is a lower limit of the differential pressure that increases a slip ratio of the lockup clutch or reduces a slip amount of the lockup clutch.

A lockup disengagement control device for an automatic transmission including a torque converter including a lockup clutch, and a lockup control section, the lockup disengagement control device includes: when a brake is operated from a brake OFF to a brake ON during a coast traveling in an engagement state of the lockup clutch, the lockup control section being configured to sense an initial deceleration by the brake ON operation, and to set a lockup release vehicle speed to be higher as an absolute value of the initial deceleration is greater, and when a vehicle speed is sensed to be equal to or smaller than the set lockup release vehicle speed in a middle of a brake deceleration scene by the brake ON operation, the lockup control section being configured to disengage the lockup clutch.

A work vehicle includes an engine, a drive wheel, a power transmission mechanism configured to transmit a driving power of the engine to the drive wheel, and a control unit configured to control the power transmission mechanism. The power transmission mechanism has a torque converter including a first clutch, and a second clutch coupled to the torque converter. The control unit controls an oil pressure supplied to the first clutch to a predetermined oil pressure when the second clutch is partially engaged.

Systems and methods for starting an engine that is incorporated into a hybrid vehicle driveline are described. In one example, a torque converter clutch is fully opened if a threshold amount has transpired after a request for torque converter clutch slip is requested but not delivered. Further, the torque converter clutch may be fully opened if a commanded torque converter clutch torque capacity is less than a threshold torque capacity.

The disclosure provides a control method, a control device for vehicular automatic transmission, and a recording medium. The control device includes an ON/OFF control solenoid controlling LC to either ON or OFF, and an LC pressure control linear solenoid controlling LC pressure between a released state and a fully engaged state. The control device acquires, when an accelerator pedal opening of a vehicle is on a deceleration side in a fully closed state, a torque converter slip ratio when the ON/OFF control solenoid maintains ON for a predetermined time period and the LC pressure control linear solenoid is controlled such that the LC pressure is OFF, and determines whether or not the second solenoid has a high-pressure fixation failure according to whether or not the slip ratio is within a predetermined range from a slip reference value.

Provided is a lockup control device and a lockup control method for a vehicle power transmission device provided with a fluid transmission device including a lockup clutch. The lockup clutch is controlled to perform slip-engagement such that a differential rotation between an input-side rotating member and an output-side rotating member of the fluid transmission device is a target differential rotation set in advance, and the target differential rotation is corrected based on transition of a heat accumulation amount applied to friction members of the lockup clutch.