A power-split drive train having a main drive, three output shafts (Ab1, Ab2, Ab3) and a continuously variable powersplit transmission with three additional drive units. The transmission enables rotational speed variability at the shafts (Ab1, Ab2, Ab3). Furthermore, each drive unit (2a, 2b, 2c) has a respective energy converter (3a, 3b, 3c) which are all electrically connected. Drive unit (2a) has planetary gearset (4a) that is connected, via a first shaft (W1), to the main drive. Shaft (Ab1) is connected, via a second shaft (W2), to gearset (4a) and energy converter (3a) is connected, via a third shaft (W3), to gearset (4a). The drive unit (2a) is at least indirectly connected to drive unit (2b) which is connected by a fifth shaft (W5) to shaft (Ab2). Drive unit (2a) is at least indirectly connected to drive unit (2c) which is connected by a seventh shaft (W7) to shaft (Ab3).

A power-split drive train for a working machine having a main drive element, drive output shafts (Ab1, Ab2, Ab3), and a continuous power-split transmission with three drive units (2a, 2b, 2c). The transmission enables all three output shafts to be operated at the same time with rotational speed variability. A first drive unit (2a) has two energy converters while second and third drive units (2b, 2c) each comprise one energy converter. All four energy converters are functionally connected to an electric line. The first unit (2a) is connected, via a first shaft, to the main drive element and, via a second shaft, to output shaft (Ab1). The first unit (2a) is connected to drive unit (2b) which is connected, via a third shaft, to output shaft (Ab2). The first drive unit (2a) is connected to drive unit (2c) which is connected, via a fourth shaft, to output shaft (Ab3).

In a vehicle including an engine, drive wheels, a power transmission system, and an electronic control unit, during shifting of an automatic transmission, a hydraulic command value of a clutch is set to a higher value as an engine power command value is larger, so that a shift or change of the speed ratio proceeds in an electronic continuously variable transmission and the automatic transmission, in accordance with engine power as a product of the engine speed and engine torque, rather than torque of the engine, etc.

A plurality of virtual gear positions are established by an electric continuously variable transmission, and the number of speeds of the virtual gear positions is equal to or larger than the number of speeds of mechanical gear positions of a mechanical stepwise variable transmission. One or two or more virtual gear positions is/are assigned to each mechanical gear position, and shifts among the mechanical gear positions are performed in the same timing as the shift timing of the virtual gear positions. Thus, shifting of the mechanical stepwise variable transmission is accompanied by change of the engine speed Ne, and the driver is less likely to feel uncomfortable even if shift shock occurs during shifting of the mechanical stepwise variable transmission.

A method is provided to control a hybrid powertrain comprising an internal combustion engine; a gearbox with input and output shafts; a range gearbox, connected to the output shaft; a first planetary gear, connected to the input shaft; a second planetary gear, connected to the first planetary gear; a first electrical machine, connected to the first planetary gear; a second electrical machine, connected to the second planetary gear; at least one gear pair, connected with the first planetary gear and the output shaft; and at least one gear pair, connected with the second planetary gear and the output shaft, wherein the internal combustion engine is connected with the first planetary gear via the input shaft. The method comprises the steps: a) engaging a gear by way of connecting two rotatable components in the first planetary gear; b) connecting the at least one gear pair, connected with the second planetary gear and the output shaft; c) connecting a sixth gear pair, arranged between a countershaft and the range gearbox with the countershaft, so that the countershaft is connected with the output shaft via the range gearbox; d) controlling the range gearbox from a low range position to a neutral state, in which no torque transmission occurs through the range gearbox; e) controlling two rotatable components in the range gearbox towards achieving a synchronized rotational speed with the assistance of the first electrical machine; f) connecting the rotatable components with the use of a shiftable third clutch device; and g) engaging a gear by way of connecting two rotatable components in the second planetary gear.

Provided is a method to control a hybrid powertrain to achieve a reverse drive, wherein the hybrid powertrain comprises an internal combustion engine; a gearbox with an input 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 the output shaft; and one gear pair connected with the second main shaft and the output shaft, wherein the internal combustion engine is connected with the first planetary gear via the input shaft. The method comprises: ensuring that moveable component parts in the first planetary gear are disconnected from each other and/or that moveable component parts in the second planetary gear are disconnected from each other; ensuring that an output shaft in the internal combustion engine is prevented from rotating; and controlling the first electrical machine and/or second electrical machine to achieve a negative torque in the output shaft via the first main shaft and/or second main shaft.

The present invention relates to a hybrid powertrain, comprising an internal combustion engine; a gearbox with an input shaft and an output shaft; a first planetary gear, connected to the input shaft; a second planetary gear, connected to the first planetary gear; a first electrical machine, connected to the first planetary gear; a second electrical machine, connected to the second planetary gear; at least one gear pair, connected with the first planetary gear and the output shaft; and at least one gear pair, connected with the second planetary gear and the output shaft, wherein the internal combustion engine is connected with the first planetary gear via the input shaft, wherein a countershaft is arranged between the respective first and second planetary gears and the output shaft; and the countershaft is connected with the output shaft via a range gearbox.

A method is provided to control a hybrid powertrain comprising an internal combustion engine; a gearbox with input and output shafts; a range gearbox connected to the output shaft; a first planetary gear, connected to the input shaft; a second planetary gear, connected to the first planetary gear; first and second electrical machines, respectivley connected to the first and second planetary gears; a gear pair connected with the first planetary gear and the output shaft; and a gear pair, connected with the second planetary gear and the output shaft, wherein the internal combustion engine is connected to the input shaft. The method comprises: a) engaging a gear by connecting two rotatable components in the first planetary gear; b) connecting the second or the fourth gear pair; c) connecting a sixth gear pair, arranged between a countershaft and the range gearbox to the countershaft, so that the countershaft is connected with the output shaft via the range gearbox; d) synchronising the rotational speed between two rotatable components in the range gearbox; e) connecting the rotatable components with a shiftable third clutch device; and f) engaging a gear by way of connecting two rotatable components in the second planetary gear.

An infinitely variable transmission (IVT) provides a plurality of transmission modes. At least one mode is a serial mode and at least one other mode is a split-path mode. The IVT provides substantially seamless shifting between the plurality of transmission modes.

A power transmission system includes first differential mechanism connected to an engine, and second differential mechanism. The first differential mechanism includes a first rotating element connected to the engine, and second and third rotating elements. The second differential mechanism includes a fourth rotating element connected to second rotating element, fifth rotating element connected to a first electric rotary machine, and sixth rotating element that is an output element of the second differential mechanism. The power transmission system further includes at least one of a first clutch and brake, and a second clutch. The first clutch is configured to releasably couple two of the first, second and third rotating elements to each other. The brake is configured to releasably couple the third rotating element to a stationary element. The second clutch is configured to releasably couple the third rotating element to one of the fifth and sixth rotating elements.