Abstract: A method is provided for starting a piston engine of a hybrid drive in an electric travel state. The hybrid drive includes at least the piston engine, an electric motor, a transmission, and a clutch situated between the piston engine and the electric motor. A converter lockup clutch, which is switchable into a slip state, is also provided. A slip is set at the converter lockup clutch, and a speed of the electric motor is then increased. The speed and the torque either do not change or only change in a predefined range at the output side of the converter lockup clutch. The clutch is closed to transmit a torque pulse, so that a first top dead center of the piston of the piston engine may be overcome. A predefined slip is then set at the clutch.

Abstract: A method for controlling a drivetrain for a road vehicle, in particular for a hybrid vehicle, is provided. The drivetrain includes at least an electric motor, an electric energy accumulator, and an active connection to at least one drivable axle. In the recuperation mode, thus, when an electric motor is operating as a generator for generating electric energy for charging an electric energy accumulator, the generated electric energy is transmitted at least partly to at least one electric heating resistor in order to convert the energy into heat.

Abstract: A method for controlling a drivetrain for a hybrid vehicle is provided. The drivetrain has at least one internal combustion engine, a torque converter and an operational link to at least one drivable axle, an electrical energy store, and an electrical machine, which is usable as a generator for charging the electrical energy store during a recuperation operation. The electrical machine is provided on the pump wheel and the operational link being provided on the turbine wheel of the torque converter. A torque is introduced from the drivable axle via the operational link and through the turbine wheel into the liquid of the torque converter in recuperation operation in order to be dissipated as heat.

Abstract: A method is employed for starting an internal combustion engine in a hybrid vehicle drive which is driven by an electric motor. A speed of the internal combustion engine is adjusted to a target speed. The internal combustion engine speed exceeds the target speed over a predefined time by a predetermined speed differential.

Abstract: The invention relates to a method for operating a drive train (1) comprising an internal combustion engine (2), an electric motor (10) and an automatic transmission (11), in which, during an operating state with the electric motor (10) switched on and the internal combustion engine (2) switched off, the internal combustion engine (2) is engaged by a transmission of torque to the internal combustion engine (2), used to accelerate the internal combustion engine (2), being coupled in time with a downshift operation in the automatic transmission (11).

Abstract: A system and method for controlling a hybrid vehicle drive has a device for detecting a charging power of a heavy-duty battery for an electric motor, a device for determining at least one fuel consumption parameter for several different transmission gear positions at the detected charging power and for determining an optimized gear position in which the determined fuel consumption parameter indicates an optimized fuel consumption. The determining device controls the gear position of the transmission to the determined optimized gear position by via a transmission control device.

Abstract: A drivetrain of a motor vehicle has an internal combustion engine, an electric motor, a transmission, and a torque converter with a converter bypass clutch. The drivetrain is controlled such that, during an electric operating mode in which the internal combustion engine is deactivated and the electric motor is activated, and/or during a recuperation operating mode in which the internal combustion engine is deactivated and the electric motor is operated as a generator, the converter bypass clutch is permanently closed, at least between shift processes of the transmission, in order to bypass the torque converter.

Abstract: A method operates a drive train the is formed of an internal combustion engine, an electric motor, a transmission and a first clutch that connects the internal combustion engine to the electric motor. During an operating state for applying a current requested torque to a transmission input with the electric motor switched on and the internal combustion engine switched off, the internal combustion engine is connected into the circuit by increasing the torque applied to the drive train by the electric motor before the internal combustion engine starts, in such a way that only the current requested torque is applied to the transmission input. Excess torque is extracted from the drive train by actuating the first clutch and applying the excess torque to the internal combustion engine in order to accelerate it. The internal combustion engine is started when its starting state is reached.

Abstract: A method and a device for controlling a hybrid vehicle drive. The device contains a multiplicity of control parameter sets with different set point charge states for a high performance battery of the electric motor. The set point charge states are assigned to a respective operating mode of the vehicle. A definition device for defining a current operating mode of the vehicle, as a result of which a control parameter set which corresponds to the defined current operating mode of the vehicle can be used to control a charge mode of the high performance battery of the electric motor with a corresponding set point charge state.

Abstract: A method and a device control a hybrid vehicle drive. The device contains a multiplicity of control parameter sets having different recovery torques for a conversion control device which sets a recovery torque of the electric motor in an overrun phase, which recovery torques are assigned a respective driving mode indicator. A definition device is provided for defining a current driving mode indicator, as a result of which a control parameter set corresponding to the defined current driving mode indicator can be used to control the conversion control device in an overrun phase of the hybrid vehicle drive.