A power transmission device mounted on a vehicle in which operation of an engine is stopped when vehicle speed has been reduced to a predetermined vehicle speed. The device includes an oil pump driven by the engine; a hydraulic control device regulating pressure from the oil pump; a continuously variable transmission mechanism in which groove widths of a primary pulley and a secondary pulley are set by hydraulic pressure from the hydraulic control device; a hydraulic engagement element engaged by hydraulic pressure from the hydraulic control device to couple the continuously variable transmission mechanism to the engine; a clamping pressure sensor that detects clamping pressure of a belt of the continuously variable transmission mechanism; and a control device disengaging the hydraulic engagement element when the detected clamping pressure of the belt reaches less than or equal to a threshold value after operation of the engine is stopped.

A powertrain includes an engine and a transmission. A vehicle includes a body structure and the powertrain supported by the body structure. The powertrain is configured to propel the body structure. The engine includes an output shaft, and the transmission includes an input member. The powertrain further includes a torque converter operable between the output shaft and the input member. The torque converter includes a pump and a turbine. The powertrain also includes a motor-generator operable as a motor and a generator. The input member of the transmission is connected to the turbine such that torque from the torque converter is transferrable to the input member. The input member of the transmission is coupled to the motor-generator such that torque is transferred between the input member and the motor-generator.

A vehicle is provided with a mechanical oil pump (O/P) that is driven by a motor/generator (MG), an electric oil pump (M/O/P) that is driven by a sub-motor (S/M) and a second clutch (CL2) that transmits the drive force of the motor/generator (MG) to left and right drive wheels (LT, RT). When an accelerator pedal is depressed while a brake pedal is still depressed, an integrated controller (10) drives the electric oil pump (M/O/P) before the brake pedal is released, and oil pressure supplied to the second clutch (CL2) is increased.

While a vehicle is coasting with an engine being automatically stopped and a power transmission path between the engine and wheels being disengaged, when a deceleration request is made and the engine is restarted with the power transmission path being engaged, a deceleration level increases relative to the deceleration level required by a driver or the vehicle, thereby lowering drivability. A vehicle control apparatus includes a deceleration level control unit that controls the deceleration level of the vehicle such that, during travelling of the vehicle continuing to travel with a power transmission mechanism between the engine and the wheels being disengaged, when the deceleration request is made and the engine is started by an engagement of the power transmission mechanism, the deceleration level becomes a target deceleration level calculated from a first target deceleration level generated after the engagement of the power transmission mechanism is complete and a second target deceleration level generated in response to the deceleration request.

A transmission assembly including a clutch system, an accumulator, and a controller is provided. The clutch system may include a flow source. The accumulator may be selectively in communication with the flow source via a solenoid valve. The controller may be programmed to, responsive to detection of a vehicle stop and the accumulator charged below a predetermined threshold, output a command to open the solenoid valve to rapidly charge the accumulator from the flow source. The predetermined threshold may be an accumulator pressure between 700 kPa and 900 kPa. The controller may be further programmed to, responsive to detection of the accumulator being charged to or above the predetermined threshold, output a shut down command to an engine in communication with the transmission assembly and to output a close command to the solenoid valve. The flow source may be a pump out circuit or a line pressure circuit.

A method for operating a vehicle drivetrain (1) includes proceeding, in the presence of the demand for activation of the engine start-stop function of the vehicle drivetrain (1) and a simultaneously shut-down drive machine (2), from an operating state of the vehicle drivetrain (1) during which a sailing operating function of the vehicle drivetrain (1) is active, during which the drive machine (2) is decoupled from the drive output (3), during which the positively engaging shift element (F) is open and during which a rotational speed (n_ab) of the drive output (3) is higher than a defined rotational speed at which a rotational speed difference between shift element halves of the positively engaging shift element (F) lies within a rotational speed range within which the positively engaging shift element (F) is transferrable into the closed operating state, and actuating the positively engaging shift element (F) in a closing direction no later than when the defined rotational speed is reached.

In a hydraulic control device and a hydraulic control method of a transmission, in a case that an oil supplying section is supplying a first oil to a continuously variable transmission mechanism, a TCU outputs, to an LC control valve of the oil supplying section, a control signal for giving a command to start supply of a second oil to a torque converter if a pulley pressure detected by a pressure sensor reaches a pressure threshold value.

A hydraulic circuit device for a vehicle, includes a clutch, a flow path, a fluid pump, a pressure generating device, and a control valve. The control valve is configured to determine whether a transmission start-stop function activation condition other than a vehicle speed is satisfied, determine whether a system start-stop function activation condition related to a component of the vehicle is satisfied, the component being other than the transmission, determine whether the vehicle speed is equal to or lower than a first speed threshold, and boost a line pressure of the flow path to accumulate pressure in the pressure generating device for preparing activation of the start-stop function if it is determined that the transmission start-stop function activation condition and the system start-stop function activation condition are satisfied, and if it is determined that the vehicle speed is equal to or lower than the first speed threshold.

A vehicle control device configured to be capable of executing idle stop control to automatically stop an engine when a predetermined automatic stop condition is satisfied and restart the engine when a predetermined restart condition is satisfied during the automatic stop of the engine, the vehicle control device includes: a start request detector, a shift position detector, and a delay time setting module. A start request detector detects a driver operation indicating a request for starting the engine by a driver. A shift position detector detects a shift position of a shift changer. A delay time setting module sets, on a basis of presence or absence of the driver operation and the shift position, a delay time from when the engine is restarted until when an automatic stop of the engine is permitted.

A method for operating a vehicle drivetrain (1) having a drive machine (2), an output (3) and a gearbox (4) with the gearbox (4) arranged in power flow between the drive machine (2) and the output (3) includes opening, in the presence of a demand for activation of a sailing operating function of the vehicle drivetrain (1) and a simultaneously activated engine start-stop function, a positively engaging shift element (F) while the drive machine (2) is left both decoupled from the output (3) and shut down.