In a case where a vehicle is in a first mode in which suppression of fuel consumption is prioritized, a forward gear stage selection unit selects as a forward gear stage a gear stage at which a minimum travelable vehicle speed, which is a minimum speed among a speed of the vehicle at which a driving force indicated by a driving force characteristic is equal to or greater than a travel resistance of a travel resistance characteristic, is highest, and in a case where the vehicle is in a second mode in which improvement of travel performance is prioritized, the forward gear stage selection unit selects as the forward gear stage a gear stage at which a maximum travelable vehicle speed, which is a maximum speed among the speed of the vehicle at which the driving force is equal to or greater than the travel resistance, is highest.

A vehicle lock-up clutch control method is performed in which an output of an engine is transmitted to an automatic transmission via a torque converter having a lock-up clutch. The method includes controlling a transmission torque capacity of the lock-up clutch such that a slip rotation speed of the lock-up clutch becomes zero after the lockup clutch is brought into a non-engaged state immediately after starting an accelerator operation, and when the accelerator operation is carried out during a fuel cut of the engine or in a state in which a road load and a driving force of the vehicle are balanced, and after completion of a downshift when the automatic transmission is downshifted while executing a slip control of the lock-up clutch from the non-engaged state to an engaged state during the accelerator operation.

Systems and methods for operating an engine with deactivating and non-deactivating valves are presented. In one example, estimates of engine fuel consumption for operating the engine with a plurality of cylinder modes or patterns while a transmission is engaged in different gears are determined and are used as a basis for deactivating engine cylinders.

A control device for an automatic transmission of a vehicle includes a shift control section including; a deceleration state judging section configured to judge whether a deceleration of the vehicle is a gentle deceleration state or a sudden deceleration state, and a downshift control section configured to command a plural stage downshift to downshift from a current shift stage of the automatic shift mechanism to a target shift stage that is lower than the current shift stage by two stages or more when the deceleration state judging section judges the sudden deceleration state.

A control device for an automatic transmission of a vehicle includes a shift control section including; a deceleration state judging section configured to judge whether a deceleration of the vehicle is a gentle deceleration state or a sudden deceleration state, and a downshift control section configured to command a plural stage downshift to downshift from a current shift stage of the automatic shift mechanism to a target shift stage that is lower than the current shift stage by two stages or more when the deceleration state judging section judges the sudden deceleration state.

An in-vehicle control device carries out fuel cut-off for stopping fuel injection from a fuel injection valve when a prescribed fuel cut-off condition including that a lockup clutch with which a torque converter is equipped is engaged and that an accelerator is off is fulfilled. Besides, the in-vehicle control device performs a fuel cut-off suspension process for carrying out fuel injection from the fuel injection valve and releasing the lockup clutch when there is a request to suspend fuel cut-off with the accelerator off. Also, the in-vehicle control device performs a speed increase process for performing shift control of an automatic transmission such that the rotational speed of a turbine impeller with which the torque converter is equipped becomes higher while the fuel cut-off suspension process is performed than when fuel cut-off is carried out.

An in-vehicle control device carries out fuel cut-off for stopping fuel injection from a fuel injection valve when a prescribed fuel cut-off condition including that a lockup clutch with which a torque converter is equipped is engaged and that an accelerator is off is fulfilled. Besides, the in-vehicle control device performs a fuel cut-off suspension process for carrying out fuel injection from the fuel injection valve and releasing the lockup clutch when there is a request to suspend fuel cut-off with the accelerator off. Also, the in-vehicle control device performs a speed increase process for performing shift control of an automatic transmission such that the rotational speed of a turbine impeller with which the torque converter is equipped becomes higher while the fuel cut-off suspension process is performed than when fuel cut-off is carried out.

A vehicle lock-up clutch control method is performed in which an output of an engine is transmitted to an automatic transmission via a torque converter having a lock-up clutch. The method includes controlling a transmission torque capacity of the lock-up clutch such that a slip rotation speed of the lock-up clutch becomes zero after the lockup clutch is brought into a non-engaged state immediately after starting an accelerator operation, and when the accelerator operation is carried out during a fuel cut of the engine or in a state in which a road load and a driving force of the vehicle are balanced, and after completion of a downshift when the automatic transmission is downshifted while executing a slip control of the lock-up clutch from the non-engaged state to an engaged state during the accelerator operation.

A control device for an automatic transmission of a vehicle includes a shift control section including; a deceleration state judging section configured to judge whether a deceleration of the vehicle is a gentle deceleration state or a sudden deceleration state, and a downshift control section configured to command a plural stage downshift to downshift from a current shift stage of the automatic shift mechanism to a target shift stage that is lower than the current shift stage by two stages or more when the deceleration state judging section judges the sudden deceleration state.

A control device for an automatic transmission of a vehicle includes a shift control section including; a deceleration state judging section configured to judge whether a deceleration of the vehicle is a gentle deceleration state or a sudden deceleration state, and a downshift control section configured to command a plural stage downshift to downshift from a current shift stage of the automatic shift mechanism to a target shift stage that is lower than the current shift stage by two stages or more when the deceleration state judging section judges the sudden deceleration state.