A method is provided to start a hybrid powertrain to optimize fuel consumption, wherein such hybrid powertrain comprises a combustion engine; a gearbox with input shaft and output shaft; a first planetary gear, connected to the input shaft and a first main shaft; a second planetary gear, connected to the first planetary gear and a second main shaft; first and second electrical machines respectively, connected to the first and second planetary gears; one gear pair connected with the first main shaft; and one gear pair connected with the second main shaft. The method comprising: ensuring that the moveable parts of each of the first and second planetary gears are respectively disconnected from each other; bringing the combustion engine to a predetermined engine speed (n.sub.ice); and controlling the first and the second electrical machine in such a way that a desired torque (T.sub.Drv) is achieved in the output shaft.

At a time of HV traveling entailing a load operation of an engine in a CD mode, an electronic control unit sets a required torque Tr* by using a map for a CS mode, in which the required torque Tr* is set to be lower than in a map for the CD mode, as at a time of the CS mode. Then, the electronic control unit control the engine and a motor for traveling in accordance with the required torque Tr*. Accordingly, a rise in the required torque Tr* can be suppressed compared to setting of the required torque Tr* using the map for the CD mode and a sense of high-rpm idling attributable to a rise in a rotation speed of the engine can be inhibited from being felt by a driver.

A system and a method for controlling torque intervention of a hybrid electric vehicle including a motor and an engine as power sources that includes: a driving information detector detecting a running state of the vehicle and demand information of a driver of the vehicle; a transmission control unit (TCU) requesting torque reduction while shifting of the vehicle based on a signal from the driving information detector; a traction control system (TCS) requesting torque reduction by outputting an intervention torque for preventing a wheel slip of the vehicle; and a controller controlling torque intervention by dividing a request amount of torque reduction into the engine and the motor when receiving the torque reduction request from the TCU or the TCS, wherein the controller firstly reduces a motor assist torque when a state of the motor before the torque intervention is an assist state, maintains a motor charging torque when the state of the motor before torque intervention is a charging state, and divides an additional reduction requirement in proportion to an available reduction range of the engine and an available reduction range of the motor.

A drive system for a vehicle comprises two electrical machines arranged between a combustion engine and an input shaft to a gearbox. The first machine's rotor and the input shaft of the gearbox are each connected to a separate component of a planetary gear. The second electrical machine's rotor is connected with the output shaft of the combustion engine, which is connected with another component of the planetary gear. A first locking means may be moved between a locked position, in which the planetary gear's three components rotate at the same rotational speed, and a release position, allowing for different rotational speeds. A second locking means is moveable between a locked position, in which the output shaft of the combustion engine is locked together with the second machine's rotor and a release position, in which the combustion engine's output shaft is disconnected from the second machine's rotor.

Disclosed is a method for control a vehicle with a drive system comprising an output shaft of a combustion engine and a planetary gear with a first and a second electrical machine, connected via their rotors to the components of the planetary gear, the vehicle is started by controlling the first electrical machine to achieve a torque thereof, so that the requested torque is transmitted to the planetary gear's output shaft, and controlling the second electrical machine to achieve a torque, so that the desired power to electrical auxiliary aggregates and/or loads in the vehicle, and/or electric energy storage means, if present in the vehicle, for exchange of electric energy with the first and second electrical machine is achieved.

In a method for controlling a vehicle with a drive system comprising a power unit configuration adapted to provide power for the vehicle's operation, and further comprising a planetary gear and a first and second electrical machine, connected to components in the planetary gear via their rotors, a locking means is moved from a release position, in which the planetary gear's components are free to rotate independently of each other, to a locked position, in which two of the planetary gear's components are locked together, so that the three components in the planetary gear rotate with the same speed. The power unit configuration is controlled in order to achieve a synchronous, or substantially synchronous, rotational speed between the input and output shaft of the planetary gear, and the locking means are then moved to the locked position.

In a method for controlling a vehicle with a drive system comprising a power unit configuration adapted to provide output for the vehicle's operation, and further comprising a planetary gear and a first and second electrical machine, connected to components in the planetary gear via their rotors, a locking means is moved from a locked position, in which two of the planetary gear's components are locked together, so that the three components of the planetary gear rotate with the same speed, to a release position, when the vehicle is driven with the locking means in a locked position, by carrying out the following method steps. The power unit configuration is controlled in order to achieve torque balance between the components that are locked together by the locking means, and such locking means are moved into a release position, when said torque balance prevails.

In a method for controlling a vehicle with a drive system comprising an output shaft in a combustion engine, a planetary gear and a first and second electrical machine connected to the planetary gear, the turning off of the combustion engine is achieved when the vehicle is driven with the combustion engine running, and a transition to operation of the vehicle with the electrical machines is achieved by ensuring that the second electrical machine's rotor is connected with the combustion engine's output shaft, that injection of fuel into the combustion engine is interrupted and that the second electrical machines rotational speed is controlled towards and until a standstill, whereupon the combustion engine's output shaft is disconnected from the second electrical machine and the planetary gear.

Disclosed is a method for control of a vehicle with a drive system comprising an output shaft in a combustion engine and a planetary gear with a first and a second electrical machine connected via their rotors to the components in the planetary gear, a supply of electrical power to electrical auxiliary units and/or loads present in the vehicle is carried out, by way of the combustion engine being kept running with its output shaft connected with the second electrical machine's rotor, and the electrical auxiliary units and/or loads being supplied with electrical power via the first electrical machine and/or the second electrical machine.

In a method for controlling a vehicle with a drive system comprising an output shaft of a combustion engine and a planetary gear with a first and a second electrical machine, connected via their rotors to the components of the planetary gear, the combustion engine is started while the vehicle is driven by ensuring that the rotor of the second electrical machine is connected with the output shaft of the combustion engine, and controlling such electrical machine's rotational speed towards the combustion engine's idling speed, whereupon fuel injection into the combustion engine is carried out to start the latter.