A control device for a vehicle is provided. The control device includes an automatic transmission constituted of a stepwise variable transmission mechanism configured to switch a plurality of shift stages by engagement and disengagement of a plurality of friction engaging elements, an engine as a driving source, a motor configured to assist a driving force of the engine, a hydraulic controller configured to supply a hydraulic pressure to control the engagement and the disengagement of the friction engaging element, and a control unit configured to control the automatic transmission to a target speed ratio through changing the shift stage of the stepwise variable transmission mechanism. The control unit performs a learning control that learns at least one of hydraulic pressure of the engagement and the disengagement of the friction engaging element, and inhibits the assist of the driving force to the engine by the motor in performing the learning control.

In a transmission control device, a controller determines failure of a rotation sensor. A hydraulic control circuit and the controller variably control a speed ratio of a variator. The hydraulic control circuit and the controller variably control a gear position of a sub-transmission mechanism, and in a case where the failure is determined, fix the gear position of the sub-transmission mechanism to first speed. The hydraulic control circuit and the controller fix the gear position of the sub-transmission mechanism to the first speed during a vehicle stop in a case where the gear position of the sub-transmission mechanism upon a determination of the failure is second speed.

A transmission includes a sub-transmission mechanism, a variator having lower shift responsiveness than the sub-transmission mechanism, and a controller configured to carry out a coordinated shift for changing a speed ratio of the variator in a direction opposite to a changing direction of a speed ratio of the sub-transmission mechanism as the sub-transmission mechanism is shifted so that a through speed ratio reaches a target through speed ratio. The controller sets a target speed ratio of the sub-transmission mechanism on the basis of the target through speed ratio and an actual speed ratio of the variator in carrying out the coordinated shift.

In a transmission, a controller sets a target line pressure to an offset target value, which is a value obtained by adding a positive offset amount to one of a target PRI pressure and a target SEC pressure, in a speed ratio range in which the offset target value is higher than the other at least during an inertia phase in a sub-transmission mechanism when a coordinated shift is carried out. At that time, the one of the target PRI pressure and the target SEC pressure is the target SEC pressure when a variator is downshifted by the coordinated shift while being the target PRI pressure when the variator is upshifted by the coordinated shift.

When the speed ratio of a belt-type continuously variable transmission is equal to or larger than a predetermined threshold value, switching between a first power transmission path including a gear transmission mechanism and a second power transmission path including a belt-type continuously variable transmission is performed by means of clutches, so as to reduce a difference in an input shaft rotational speed applied to the clutches before and after the switching.

As a mode switching shift line when a sub-transmission mechanism is switched from a first-speed to a second-speed, a first mode switching shift line, which prioritizes a learning of a hydraulic pressure with which a Low brake starts to slip and a learning of a hydraulic pressure with which a High clutch starts to transmit a torque, or a second mode switching shift line, which is a shift line in a Low side with respect to the first mode switching shift line and prioritizes a fuel efficiency of an engine is selected, and the sub-transmission mechanism is switched from the first-speed to the second-speed on the basis of the selected mode switching shift line.

In a transmission control device, a controller determines failure of a rotation sensor. A hydraulic control circuit and the controller variably control a speed ratio of a variator, and in a case where the failure is determined, execute first control of restricting a shift range of the variator. The hydraulic control circuit and the controller variably control a gear position of a sub-transmission mechanism, and in a case where the failure is determined, execute second control of fixing the gear position of the sub-transmission mechanism to first speed. The hydraulic control circuit and the controller execute the second control at a different timing from the first control in a case where the gear position of the sub-transmission mechanism upon a determination of the failure is second speed.

Methods and systems for a hydromechanical transmission are provided herein. In one example, the transmission operating method includes asynchronously shifting between a first pair of drive ranges in the transmission via operation of two clutches and a variable displacement hydraulic pump in a hydrostatic assembly. In the method, asynchronously shifting between the two drive ranges includes a plurality of phases that include a swiveling phase where a speed of the hydrostatic assembly is inverted.

A control device for a vehicle is provided. The control device includes an automatic transmission constituted of a stepwise variable transmission mechanism configured to switch a plurality of shift stages by engagement and disengagement of a plurality of friction engaging elements, an engine as a driving source, a motor configured to assist a driving force of the engine, a hydraulic controller configured to supply a hydraulic pressure to control the engagement and the disengagement of the friction engaging element, and a control unit configured to control the automatic transmission to a target speed ratio through changing the shift stage of the stepwise variable transmission mechanism. The control unit performs a learning control that learns at least one of hydraulic pressure of the engagement and the disengagement of the friction engaging element, and inhibits the assist of the driving force to the engine by the motor in performing the learning control.