A shift control device for a vehicle includes: an engine; a shift mechanism disposed between the engine and driving wheels; a shift control section configured to control a transmission gear ratio of the shift mechanism; and a fuel cut control section configured to stop a fuel supply to the engine, at least when an accelerator pedal is in a release state, and when an engine speed is equal to or greater than a predetermined rotation speed, the shift control section being configured to perform a minimum rotation speed restriction control to control the transmission gear ratio of the shift mechanism so that the minimum rotation speed of the engine is equal to or greater than the predetermined rotation speed regardless of a vehicle front condition and an accelerator operation condition.

A shift control device for a vehicle includes: an engine; a shift mechanism disposed between the engine and driving wheels; a shift control section configured to control a transmission gear ratio of the shift mechanism; and a fuel cut control section configured to stop a fuel supply to the engine, at least when an accelerator pedal is in a release state, and when an engine speed is equal to or greater than a predetermined rotation speed, the shift control section being configured to perform a minimum rotation speed restriction control to control the transmission gear ratio of the shift mechanism so that the minimum rotation speed of the engine is equal to or greater than the predetermined rotation speed regardless of a vehicle front condition and an accelerator operation condition.

An engine control method includes determining an intention of a driver for acceleration during vehicle traveling, stopping fuel supply to an engine when a determination is made that the driver does not have the intention for acceleration, detecting a speed of the vehicle during inertial traveling, with fuel supply to the engine kept stopped, permitting restart of the engine when a determination is made that the driver has the intention for acceleration after stopping the fuel supply to the engine, prohibiting the restart of the engine until an engine rotational speed drops to or below a predetermined rotational speed threshold, even when the restart of the engine is permitted, restarting the engine after the engine rotational speed drops to or below the predetermined rotational speed threshold, and changing the rotational speed threshold depending on the detected speed. The rotational speed threshold increases with increase in the detected speed.

An engine control method includes determining an intention of a driver for acceleration during vehicle traveling, stopping fuel supply to an engine when a determination is made that the driver does not have the intention for acceleration, detecting a speed of the vehicle during inertial traveling, with fuel supply to the engine kept stopped, permitting restart of the engine when a determination is made that the driver has the intention for acceleration after stopping the fuel supply to the engine, prohibiting the restart of the engine until an engine rotational speed drops to or below a predetermined rotational speed threshold, even when the restart of the engine is permitted, restarting the engine after the engine rotational speed drops to or below the predetermined rotational speed threshold, and changing the rotational speed threshold depending on the detected speed. The rotational speed threshold increases with increase in the detected speed.

A first control unit executes a valve stop inertial running including stopping an intake valve and an exhaust valve in a closed state during rotation of an output shaft, stopping supply of fuel to an engine, and setting a clutch in an engaged state to drive pistons of the engine by a rotational force from driving wheels. A second control unit executes a valve operation running including operating the intake valve and the exhaust valve during the rotation of the output shaft, and supplying the fuel to the engine based upon an intake conduit pressure. When a cancellation request is made during execution of the valve stop inertial running, a transient control unit operates the intake valve and the exhaust valve, and controls a throttle valve to an idling opening or less, thereby supplying a negative pressure to an intake passage.

When an alternator load torque Talt is larger than a threshold , a lockup clutch is released. Thus, a deceleration G can be restrained from becoming too large due to the alternator load torque Talt. Besides, the threshold is changed in accordance with a speed ratio of a continuously variable transmission. Thus, the deceleration G can be favorably controlled within a predetermined range. For example, in a vehicle state where a deceleration is unlikely to be achieved due to the smallness of the speed ratio , the threshold is large. Therefore, the lockup clutch is unlikely to be released, and the deceleration G is likely to be secured.

When an accelerator pedal is released while a vehicle is running, a lockup clutch is unlocked. Simultaneously, ignition timing is retarded and a fuel-cut operation to stop fuel supply to an internal combustion engine is performed. However, when it is predicted that a fuel recovery is to be performed after unlocking the lockup clutch, execution of the fuel-cut operation is prohibited. A shock due to the fuel recovery after the fuel-cut operation performed when the accelerator pedal is released is thereby prevented.

A first control unit executes a valve stop inertial running including stopping an intake valve and an exhaust valve in a closed state during rotation of an output shaft, stopping supply of fuel to an engine, and setting a clutch in an engaged state to drive pistons of the engine by a rotational force from driving wheels. A second control unit executes a valve operation running including operating the intake valve and the exhaust valve during the rotation of the output shaft, and supplying the fuel to the engine based upon an intake conduit pressure. When a cancellation request is made during execution of the valve stop inertial running, a transient control unit operates the intake valve and the exhaust valve, and controls a throttle valve to an idling opening or less, thereby supplying a negative pressure to an intake passage.