Systems and methods for transitioning a torque source between speed control and torque control modes during a vehicle creep mode are disclosed. In one example, torque of an electric machine is adjusted in response to a torque converter model. The torque converter model provides for a locked or unlocked torque converter clutch.

A shift control method for a rapidly accelerating DCT vehicle, may include determining, by a controller, whether or not there occurs a power-on upshift situation in which an accelerator pedal is depressed 50% or more; estimating, by the controller, a predicted time remaining until an engine speed enters a red zone when engagement of a target shift-stage gear is completed under the power-on upshift situation; and performing, by the controller, a torque phase by updating a predetermined target torque phase time to fall within the predicted time when the predicted time is less than the target torque phase time and controlling a disengaging clutch and an engaging clutch depending on the updated target torque phase time.

A vehicle includes an engine and electric machine connected to a planetary gear, a one-way clutch, and a controller. The one-way clutch transfers torque from the planetary gear to an overdrive gear. The controller, in response to a condition requiring disengagement of the one-way clutch, increases a torque of the electric machine based on a torque command for the electric machine and the torque transferred from the planetary gear to the overdrive gear.

A system and method for controlling engine clutch slip for a hybrid vehicle, in which it is determined whether an engine clutch has entered a slip mode and lubrication of the engine clutch is easily achieved through an additional lubrication hydraulic pressure circuit whenever the engine clutch enters the slip mode, thereby achieving the engine clutch slip control in all shift ranges including low-speed and medium-speed ranges and maintaining the heat energy that is generated from the engine clutch at a predetermined level or lower.

A vehicle is provided that includes a motor connected to vehicle wheels and configured to generate electrical power. A first rotational speed detector detects rotational speed of the motor and an engine generates mechanical power. A second rotational speed detector detects rotational speed of the engine. A clutch is disposed between the engine and the motor to open and close the connection between the engine and the motor. A controller diagnoses a failure of the clutch and outputs an instruction to open the clutch and an instruction to turn off the engine when the clutch has a failure. The controller determines whether the clutch is successfully opened based on the detected rotational speed of the motor and the detected rotational speed of the engine, executes a series driving mode when that the clutch is successfully opened and speed limit driving when that the clutch has failed to be opened.

Methods and systems are provided for operating a vehicle driveline where the vehicle driveline does not include a torque converter. In one example, a method comprises controlling a capacity of a clutch configured to transmit torque between an engine and a transmission, and an output of an electric motor positioned in a driveline of the hybrid vehicle during a vehicle launch to emulate a performance of a torque converter positioned in the driveline of the vehicle. In this way, vehicle launch maneuvers may be conducted for vehicles that are equipped with a clutch and an electric motor, such that said launch maneuvers mimic those of a vehicle with a torque converter, which may improve customer satisfaction and improve engine efficiency.

A method for operating a powertrain of a hybrid vehicle is provided. The method includes outputting via a controller an engine speed command that is based on a predicted impeller speed of a torque converter and corresponds to the accelerator tip-in to output a torque from the engine to wheels of the vehicle in response to detection of an accelerator pedal tip-in greater than a predetermined threshold. The method may also include accessing a history of impeller speed outputs of the hybrid vehicle to obtain the predicted impeller speed. The engine speed command may set engine speed substantially equal to or greater than the predicted impeller speed. The predetermined threshold may be based on a driver requested torque output of the wheels in which torque from the torque converter to the wheels results in saturation.

A parallel hybrid vehicle includes an engine and a motor separated along a driveshaft by a clutch. The motor can operate (either alone or in combination with the engine) to provide positive drive torque to the wheels. The motor can also act as a generator and provide negative torque when converting mechanical energy from the driveshaft into mechanical energy to be stored in a battery. The clutch selectively couples the motor to the engine. Torque and its effects on the clutch can vary dramatically when the motor changes from providing positive and negative torque, and vice versa, while the engine is running. At least one controller in the vehicle is programmed to, while the engine is running, initiate an increase in pressure at the clutch in response to an anticipated change in torque provided by the motor from positive to negative or from negative to positive.

Systems and methods for transitioning a torque source between speed control and torque control modes during a vehicle creep mode are disclosed. In one example, torque of an electric machine is adjusted in response to a torque converter model. The torque converter model provides for a locked or unlocked torque converter clutch.

Systems and methods for transitioning a torque source between speed control and torque control modes during a vehicle creep mode are disclosed. In one example, torque of an electric machine is adjusted in response to a torque converter model. The torque converter model provides for a locked or unlocked torque converter clutch.