Methods and systems are provided for operating a driveline of a hybrid vehicle that may include an internal combustion engine, a rear drive unit electric machine, an integrated starter/generator, and a transmission are described. In one example, torque capacity of an on-coming clutch is adjusted during an inertia phase of a power-on upshift to improve shift smoothness.

A speed reducer includes a planetary gear, a first ring gear and a second ring gear. The planetary gear is a helical gear and has planetary gear teeth each of which is tilted relative to an axis of the planetary gear. The first ring gear is a spur gear and has first ring gear teeth which extend in parallel with an axis of the first ring gear and are configured to mesh with the planetary gear teeth. The second ring gear is a spur gear and has second ring gear teeth which extend in parallel with an axis of the second ring gear and are configured to mesh with the planetary gear teeth.

A control device is configured to perform torque response slip control for bringing an engagement device into a slip engaged state so that transfer torque of the engagement device has a magnitude corresponding to required torque, shift control for shifting the shift speed of an automatic transmission, and transfer torque limit control for limiting the transfer torque of the engagement device to a value equal to or less than a limit value smaller than the required torque, the required torque being torque that is required to be transferred from the rotating electrical machine side to the automatic transmission via the engagement device that connects and disconnects power transmission between the rotating electrical machine and the automatic transmission. The control device performs the transfer torque limit control instead of the torque response slip control in a case where the torque response slip control is being performed when performing the shift control.

A method for controlling a hybrid vehicle may include detecting, in a controller, a circumstance that a vehicle is rapidly decelerated and then rapidly accelerated; confirming that a transmission clutch slipped in the controller as a result of performing the detecting; reducing a driving torque and a motor speed while minimizing a hydraulic pressure of the transmission clutch in the controller, in the case that the transmission clutch has slipped as a result of performing the confirming; determining when the transmission clutch is available for synchronization in the controller while performing the reducing; and normalizing the hydraulic pressure of the transmission clutch and the driving torque in the controller, in the case that it is determined that the transmission clutch is available for synchronization as a result of performing the determining.

A method for operating a drive device for a motor vehicle including an internal combustion engine and an electrical machine. A drive shaft of the internal combustion engine can be coupled to a machine shaft of the electrical machine by a shift clutch. The shift clutch is opened in a first shift state for decoupling the internal combustion engine and the electrical machine, and is closed in a second shift state for coupling the internal combustion engine and the electrical machine. When a switching occurs from the first shift state to the second shift state, a clutch target torque that is set at the shift clutch is determined in a first mode of operation by a closed-loop control, and in a second mode of operation is determined by an open-loop control.

Some embodiments of the present invention comprise a method of controlling a powertrain of a vehicle, the powertrain comprising drive torque means, a transmission and a driveline, the drive torque means comprising an internal combustion engine, the method comprising: detecting that coasting entry criteria have been met; causing the powertrain to assume a first coasting mode for a first time period in which the drive torque means delivers positive drive torque to the driveline to substantially balance powertrain losses; determining a value for at least one parameter, the or each parameter being indicative of: a probability that a demand will be made for torque to be delivered to the driveline in addition to torque delivered to substantially balance powertrain losses; or a probability that a demand will be made for braking of the vehicle; and setting the value of the first time period in dependence on the value of the or each parameter.

Systems and methods for operating a driveline of a hybrid vehicle are presented. In one example, torque capacity of a driveline disconnect is coordinated with torque control of an electric machine immediately following engine starting. The electric machine and the driveline disconnect clutch may assist starting of an engine, or alternatively, the engine may be started via a starter motor.

Disclosed is a gear shift control method of a Dual Clutch Transmission (DCT) vehicle. The gear shift control method includes a gear shift start determination step of determining whether a kick down shift, a biaxial shift determination step of determining, when the kick down shift is started, whether the gear shift is a biaxial shift; a clutch torque control step of uniformly decreasing torque of a release-side clutch and uniformly increasing torque of a connection-side clutch to synchronize revolutions per minute of a target gear input shaft with increasing revolutions per minute of an engine, a clutch synchronization determination step of determining whether the revolutions per minute of the target gear input shaft is synchronized with the revolutions per minute of the engine by the clutch torque control, and a gear shift performing step of performing gear shift control for engaging the target gear.

Methods and systems are provided for launching a vehicle in an electric-only mode of operation. In one example, a driveline operating method comprises engaging a parking pawl to an output shaft of a dual clutch transmission in response to a request to engine a vehicle into a parked state, and disengaging the parking pawl via rotating an engine via an integrated starter/generator in response to a request to propel the vehicle solely via power of an electric machine positioned downstream of the dual clutch transmission. In this way, the vehicle may be launched in the electric-only mode without activating the engine in a fueled mode of operation and then deactivating the engine, which may increase vehicle operator satisfaction and which may improve fuel economy.

Disclosed is a downshift control method for a hybrid DCT vehicle. The method includes: determining, by a controller, whether a downshift is desired while a vehicle travels on a slope having equal to or more than a predetermined reference gradient; comparing, by the controller, a motor speed with a desired shift stage input shaft speed, and selectively performing either a forward control step of increasing a motor torque in a forward direction to increase the motor speed in the forward direction or a negative control step of increasing the motor torque in a negative direction to increase the motor speed in the negative direction. Thus, it is possible to reduce the backward sliding of the vehicle by suppressing the motor speed from unnecessarily increasing and rapidly finishing the downshift.