In the present invention, an internal combustion engine is provided with a variable-compression-ratio mechanism with a variable mechanical compression ratio and the variable-compression-ratio mechanism comprises a drive device for changing the volume of a combustion chamber when a piston reaches top dead center. The drive device comprises a reverse input blocking clutch disposed in a drive power transmission path for transmitting the rotational force of a rotator. A control device estimates the reverse input torque applied to an output shaft of the reverse input blocking clutch and sets a gradient for torque output by the rotator and a continuation duration for continuing the torque increase on the basis of the reverse input torque.

In the present invention, an internal combustion engine is provided with a variable-compression-ratio mechanism with a variable mechanical compression ratio and the variable-compression-ratio mechanism comprises a drive device for changing the volume of a combustion chamber when a piston reaches top dead center. The drive device comprises a reverse input blocking clutch disposed in a drive power transmission path for transmitting the rotational force of a rotator. A control device estimates the reverse input torque applied to an output shaft of the reverse input blocking clutch and sets a gradient for torque output by the rotator and a continuation duration for continuing the torque increase on the basis of the reverse input torque.

A device for controlling a start of a vehicle includes a rotation speed obtaining unit that obtains an actual engine rotation speed of the engine, a target rotation speed computing unit that computes a target rotation speed of the engine in the slip control, a control target value computing unit that computes a control target value, which is a target value for controlling the engine rotation speed to the target rotation speed based on the actual engine rotation speed and the target rotation speed, and an instruction value computing unit that computes an instruction value for the lock-up clutch necessary to control the engine rotation speed to the control target value based on the control target value.

A power transmitting apparatus can be configured to restart an engine when the acceleration pedal is actuated in an assist-start engine speed range and can improve responsiveness of engine restart. Such a power transmitting apparatus of a vehicle can provided with a clutch for selectively transmitting or cutting off a driving power of an engine to wheels. The power transmitting apparatus can comprise an assist-controller configured to increase an engine rotational speed above an self-start rotational speed by actuating the clutch when the vehicle is decelerated and fuel supply to the engine is stopped, in response to operation of an acceleration pedal of the vehicle, when the engine rotational speed is in an assist-start range which is an engine rotational speed range lower than the self-start rotational speed and higher than a starter-start rotational speed in which the engine cannot be started by a starter.

A vehicle control system for a vehicle including an engine having a plurality of cylinders, a power transmission route between the engine and drive wheels and a clutch device for selectively connecting and disconnecting the power transmission route. The vehicle control system can disconnect the power transmission route during running to allow the vehicle to coast. The vehicle control system including an electronic control unit (ECU) for detecting, among other things, vehicle speed and operation of an accelerator by a driver, as well as for executing and controlling various components of the vehicle.