A method and device for controlling an engine clutch of a hybrid vehicle are provided. The method includes setting a target speed of an engine to change a driving mode of the hybrid vehicle from an EV mode to an HEV mode and operating a HSG to adjust an engine speed to reach the target speed. An engine clutch that connects the engine with a driving motor or disconnects the engine from the driving motor is engaged to start when the speed of the engine is maintained at the target speed. A kiss point generated when the engine clutch is in a slip state is detected to learn the kiss point of the engine clutch and an output of the engine is increased based on a driver required torque when the speed of the engine and a speed of the driving motor are synchronized after the kiss point is learned.

While a vehicle is traveling in an automatic driving mode, an auto-driving oil pressure changing unit makes the engagement pressure of hydraulic oil supplied to a release-side engagement device to be released during a downshift of a stepwise shifting unit, higher than the engagement pressure set during traveling in a manual driving mode, so that retraction of the acceleration due to a drop of drive torque during the downshift is reduced. At this time, an auto-driving rotating machine controller makes drive-side MG2 torque generated from a second rotating machine, larger than that generated during traveling in the manual driving mode, so as to speed up the progress of the downshift, and prevent retraction of the acceleration from being prolonged.

Methods and systems are provided for operating a powertrain or driveline of a hybrid vehicle that includes two electric machines and a transmission are described. In one example, vehicle propulsion is maintained while transmission operating parameters are determined for improving transmission operation. In particular, a rear drive unit maintains vehicle speed and monitors torque delivered via an output of the transmission.

A method to estimate an amount of force in a clutch pack of a clutch actuation system. The method includes engaging an actuation motor to apply a set point force to the clutch pack and monitoring a position of the actuation motor when the set point force is applied. Additionally, the method includes determining one or more clutch clamping curves and one or more clutch releasing curves based on a relationship between the position of the actuation motor and an amount of torque applied by the actuation motor at position of the actuation motor. The method further includes modeling one or more frictional characteristics of the clutch actuation system and estimating an amount of clamping and releasing force within the clutch pack by using a control unit. The amount of torque applied to the clutch pack between the clutch clamping and releasing curves at the set point force is maintained.

A clutch arrangement for a hybrid vehicle powertrain including an input shaft to be connected to a crankshaft of an internal combustion engine, an output shaft for connection to a transmission, a one-way clutch comprising an inner race connected to rotate with the input shaft and an outer race, a coupling hub rotationally coupled with the output shaft, a synchronizer ring arranged between the coupling hub and the one-way clutch, the synchronizer ring cooperating with the outer race of the one-way clutch, and a coupling sleeve unit that is selectively and axially moveable across the coupling hub. The synchronizer ring and the outer race include three positions, a neutral position, a first position, and a second position.

A vehicle driving system comprises a first motor, a second motor, a clutching mechanism disposed between a first rotary shaft of the first motor and a second rotary shaft of the second motor and configured to engage the first rotary shaft with the second rotary shaft or disengage the first rotary shaft from the second rotary shaft, a control unit connected with the first motor, the second motor and the clutching mechanism and a sensor connected with the control unit and configured to sense a travelling status of the vehicle. The control unit is configured to determine and control an operation mode the clutching mechanism and/or an operation mode and a load of the first motor and the second motor based on a signal outputted from the sensor and representing the travelling status of the vehicle.

A drive force control system appropriately controls motors each connected to a corresponding one of drive wheels, so that a vehicle can be propelled with high efficiency. First motor and second motors are controlled in such a manner that a sum of torques transmitted to a right front wheel and a left rear wheel equals to a total value of required torques of the right front wheel and the left rear wheel. A target torque of the first motor and a target torque of the second motor achieving a smallest amount of power output from an electrical power source, for the output torques from the first motor and the second motor are calculated. A torque is generated by the first motor based on the target torque of the first motor calculated, and a torque is generated by the second motor based on the target torque of the second motor calculated.

Methods and systems for controlling shifting of a tandem axle assembly are described. In one example, a method comprises adjusting torque applied at an input connection of a first axle of a tandem axle assembly based on a clutch disengagement torque while transitioning the first axle between shift settings.

A method for learning engine clutch kiss point of a hybrid vehicle is provided. The method includes adjusting a speed of a driving motor to be reduced when a deceleration event is generated in front of the hybrid vehicle and adjusting a speed of an engine to be synchronized with the speed of the driving motor. An engine clutch that connects the engine with the driving motor or disconnects the engine from the driving motor is engaged to start and then a kiss point of the engine clutch is learned by detecting the kiss point that is generated when the engine clutch is in a slip state.

A method and device for controlling an engine clutch of a hybrid vehicle are provided. The method includes setting a target speed of an engine to change a driving mode of the hybrid vehicle from an EV mode to an HEV mode and operating a HSG to adjust an engine speed to reach the target speed. An engine clutch that connects the engine with a driving motor or disconnects the engine from the driving motor is engaged to start when the speed of the engine is maintained at the target speed. A kiss point generated when the engine clutch is in a slip state is detected to learn the kiss point of the engine clutch and an output of the engine is increased based on a driver required torque when the speed of the engine and a speed of the driving motor are synchronized after the kiss point is learned.