A low-voltage hybrid powertrain system for a vehicle includes an engine that is coupled via an engine disconnect clutch to an input member of the transmission, and a low-voltage electric machine is coupled to the transmission. The powertrain system operates in an electric vehicle (EV) mode with the engine in an OFF state and with the engine disconnect clutch in an open/deactivated state. When an output torque request indicates a command for vehicle acceleration, the electric machine is controlled to generate torque in response to the output torque request and the engine is simultaneously cranked and started. Upon starting, the engine operates in a speed control mode to activate the engine disconnect clutch. The engine and the low-voltage electric machine are controlled to generate torque in response to the output torque request when the engine disconnect clutch is activated.

A method for exiting from a recuperation phase in a parallel hybrid vehicle includes, in a first step, the vehicle is in a recuperation phase, started by means of a trigger, with a predefined recuperation driving demand, and, in a second step, the electric machine is brought to an increased rotational speed during the recuperation phase. In a third step, a phase for departing from the recuperation phase is started by means of a trigger, wherein, in this phase, the internal combustion engine is made available for coupling to the electric machine, such that a target rotational speed determined between the internal combustion engine to be connected and the electric machine for the connection to the transmission input is set, and in parallel, by means of an upshift, a highest possible gear ratio for the connection to the drivetrain is set, in order to satisfy a present driving demand. In a fourth step, the departure from the recuperation phase is completed.

A method for controlling revolutions per minute (RPM) flare, in which an RPM of a transmission increases due to clutch slip, for a hybrid vehicle can include: determining whether gear-shifting is performed in a transmission of the hybrid vehicle; detecting whether RPM flare of the transmission occurs when it is determined that the gear-shifting is performed; and controlling a torque of a motor of the hybrid vehicle so as to reduce the RPM flare of the transmission by reducing the torque of the motor when the RPM flare of the transmission is detected.

Presented are engine-disconnect clutches with attendant control logic, methods for making/operating such disconnect clutches, and hybrid electric vehicles (HEV) equipped with an engine that is coupled to/decoupled from a transmission and electric motor via a disconnect clutch. A representative method for controlling an HEV powertrain includes receiving an HEV powertrain operation command, then determining a clutch mode of a multi-mode clutch device to execute the HEV powertrain operation. This multi-mode clutch device is operable in: a lock-lock mode, in which the clutch device transmits torque to and from the engine; a free-free mode, in which the clutch device disconnects the engine's output member from the transmission's input member, preventing torque transmission to and from the engine; a lock-free mode, in which the clutch device transmits torque from but not to the engine; and, a free-lock mode, in which the clutch device transmits torque to but not from the engine.

A control device that switchably has a first drive mode which is attained with the fixing mechanism being in the non-fixing state and in which a rotational speed of the input is steplessly shifted and transmitted to the output and torque of the second rotating electrical machine is transmitted to the output, and a second drive mode which is attained with the fixing mechanism being in the fixing state and the decoupling mechanism being in the non-transmitting state and in which, with the second rotating electrical machine being decoupled from the output, the rotational speed of the input is shifted according to a gear ratio of the differential gear unit and transmitted to the output.

A control system for hybrid vehicles configured to improve an acceleration feeling or enhance acceleration. In the hybrid vehicle, an engine and a first motor are connected to an input side of a transmission, and a second motor is connected to drive wheels. A controller is configured to selectively execute a first assist control to raise an input speed to the transmission by the first motor, and a second assist control to increase an output torque of the second motor, depending on a required drive force.

The present disclosure provides a control method for an engine and a transmission. The control method may include: determining whether a current mode corresponds to a coasting mode; outputting a neutral operation signal to the transmission when the current mode corresponds to the coasting mode; determining whether an operation condition corresponds to a coasting mode release condition based on the signal of each sensor; outputting a D-stage connection signal to the transmission and outputting an engine torque limitation signal to the engine when the operation condition corresponds to the coasting mode release condition; determining whether the operation condition corresponds to a release of the engine torque limitation condition according to an entry of D stage and the signals of the engine RPM and turbine RPM; and outputting a normal operation signal to the engine when the operation condition corresponds to the release of the engine torque limitation condition.

A method and a system for controlling a backlash of a powertrain included in a vehicle in connection with a gear shifting operation is presented. The method comprises: controlling, in connection with a first gear shifting operation, a clutch included in the powertrain to a slipping position, in which slipping position the clutch transfers a slipping torque that is less than a torque being transferred in a closed position for the clutch; analyzing a change of a rotational speed for an input shaft of a gearbox included in the powertrain; determining a position for the clutch, for which position the change of the rotational speed has a value corresponding to a backlash torque, the backlash torque having a predetermined value for eliminating the backlash; and utilizing the determined clutch position for controlling the clutch in connection with a second subsequent gear shifting operation.

The present disclosure provides a control method for an engine and a transmission. The control method may include: determining whether a current mode corresponds to a coasting mode; outputting a neutral operation signal to the transmission when the current mode corresponds to the coasting mode; determining whether an operation condition corresponds to a coasting mode release condition based on the signal of each sensor; outputting a D-stage connection signal to the transmission and outputting an engine torque limitation signal to the engine when the operation condition corresponds to the coasting mode release condition; determining whether the operation condition corresponds to a release of the engine torque limitation condition according to an entry of D stage and the signals of the engine RPM and turbine RPM; and outputting a normal operation signal to the engine when the operation condition corresponds to the release of the engine torque limitation condition.

A vehicle regenerative speed control device is provided that includes a controller which performs a regenerative speed control for downshifting a belt-type continuously variable transmission to the low gear ratio side and increasing a rotational speed of a transmission input shaft to which a motor generator is connected when there is a request for an increase in the regeneration amount while decelerating. The controller also imposes the limitation of staying within a Pri end command rotational speed change rate for the Pri end command rotational speed when performing a regenerative speed control for increasing the Pri end command rotational speed based on a braking operation in a brake switching region for switching from regenerative braking to hydraulic braking due to a decrease in vehicle speed.