A powertrain system includes a geartrain configured to transfer mechanical power between an internal combustion engine, torque machines and a driveline by activation of a synchronous engagement clutch. A method includes commanding activation of the synchronous engagement clutch, including commanding operations of the engine and the first and second torque machines to control members of the clutch, including monitoring speeds thereof. A magnitude of clutch slip is determined. A zero-slip feedback control routine is executed when the clutch slip approaches a zero-slip state, wherein the zero-slip feedback control routine is operative to control the engine and the first and second torque machines to control the rotational speeds of the opposed first and second members to achieve zero clutch slip. The synchronous engagement clutch is activated when the clutch slip is less than a threshold level associated with the zero-slip state.

The present invention provides a method for searching a touch point of a clutch in a dual clutch transmission, including: (a) a step of checking whether a touch point searching condition for a non-driving clutch and a driving clutch is met or not; (b) when the search condition of the step (a) is met, a step of detecting a searching point at which an absolute value of a difference between an acceleration value of an engine and an acceleration value of the driving clutch is larger than a threshold value after applying a position value of the non-driving clutch to the engine; and (c) a step of determining a position of the non-driving clutch corresponding to the searching point as the touch point.

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 vehicle lock-up clutch control device is provided to suppress engine racing when a lock-up clutch is engaged at the time a vehicle starts moving. The vehicle lock-up clutch control device is provided with a control unit that delays the rise in lock-up command pressure if a line pressure, which is the source pressure of the actual lock-up oil pressure, is rising when the lock-up clutch is engaged at the time the vehicle starts moving. The control unit executes a torque reduction in the engine at least during the delay in the lock-up command pressure.

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 vehicle lock-up clutch control device is provided to suppress engine racing when a lock-up clutch is engaged at the time a vehicle starts moving. The vehicle lock-up clutch control device is provided with a control unit that delays the rise in lock-up command pressure if a line pressure, which is the source pressure of the actual lock-up oil pressure, is rising when the lock-up clutch is engaged at the time the vehicle starts moving. The control unit executes a torque reduction in the engine at least during the delay in the lock-up command pressure.

A control device that controls a vehicle drive device in which a rotary electric machine is provided in a power transfer path that connects between an internal combustion engine and wheels. Engagement of a second engagement device is started when a change in shift range from a stop range to a running range is detected when output torque of the rotary electric machine is zero with the internal combustion engine rotating and with both the first engagement device and the second engagement device disengaged. Engagement of a first engagement device is started after engagement of the second engagement device is started, and the output torque of the rotary electric machine is increased from zero at the same time as engagement of the first engagement device is started or before engagement of the first engagement device is started.

An engine stopping system for reducing electric consumption by interrupting power supply to a motor during disengagement of a clutch is provided. The engine stopping system is applied to a vehicle in which the clutch is interposed between an engine and a power distribution device. The engine stopping system is configured to interrupt power supply to the motor while bringing the clutch into disengagement, when an input speed N.sub.in falls below a threshold value , under conditions that the engine does not generate power during engagement of the clutch, and that the motor generates electricity utilizing an inertia torque of the engine while controlling an output torque of the motor to lower the engine speed.

The present invention provides a method for searching a touch point of a clutch in a dual clutch transmission, including: (a) a step of checking whether a touch point searching condition for a non-driving clutch and a driving clutch is met or not; (b) when the search condition of the step (a) is met, a step of detecting a searching point at which an absolute value of a difference between an acceleration value of an engine and an acceleration value of the driving clutch is larger than a threshold value after applying a position value of the non-driving clutch to the engine; and (c) a step of determining a position of the non-driving clutch corresponding to the searching point as the touch point.

This clutch control device includes a clutch apparatus configured to connect and disconnect power transmission between a prime mover and an output target, a clutch actuator configured to output a driving force for actuating the clutch apparatus, and a driving mechanism configured to receive the driving force of the clutch actuator and actuate the clutch apparatus, and the driving mechanism is able to apply a driving force in either a disconnecting direction or a connecting direction to the clutch apparatus.