A power transmission system of hybrid electric vehicle includes an input shaft, counter shaft, an output shaft, first motor/generator, second motor/generator, first planetary gear set, second planetary gear set to selectively externally gear-connect fourth rotation element to third rotation element through counter shaft while being directly connected to counter shaft and to directly connect fifth rotation element to output shaft and selectively connect sixth rotation element to transmission housing, first transfer gear disposed between second rotation element and output shaft, second transfer gear disposed between third rotation element and counter shaft, variable direct connection device to selectively connect two of three rotation elements of second planetary gear set, and variable connection device to selectively connect sixth rotation element to transmission housing or selectively external gear-connect third rotation element to fourth rotation element.

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.

A drive unit is provided for hybrid vehicles capable of reducing electric power consumption during propulsion in an EV mode. The drive unit includes a first planetary gear unit to which an engine is connected, and a second planetary gear unit connected to a third rotary element of the first planetary gear unit. The drive unit includes a first engagement device that connects a first rotary element of the first planetary gear unit and a sixth rotary element of the second planetary gear unit, and a second engagement device that connects a fourth rotary element and the sixth rotary element of the second planetary gear unit.

A powertrain for a hybrid vehicle may include a complex planetary gear set including four rotation elements having first, second, third, and fourth rotation elements; a motor-generator fixedly connected to the first rotation element of the complex planetary gear set; a first brake configured to selectively connect the second rotation element of the complex planetary gear set to a transmission housing; an input shaft connected to an engine and configured to be selectively connectable to each of the first rotation element and the third rotation element of the complex planetary gear set; and an output shaft connected to the fourth rotation element of the complex planetary gear set.

A two-speed drive unit of an electric vehicle includes a planetary gear set transmission having multiple elements including a first element, a second element and a third element. A motor generator unit supplies a motive force to the planetary gear set transmission. A first stage gear transfers the motive force to the planetary gear set transmission from the motor generator unit. A second stage gear is connected through the second element to a final drive. A first torque transmitting device defining a selectable one-way clutch (SOWC) is connected to the third element.

Disclosed is a transmission apparatus comprising: a sun gear connected to the input terminal; a plurality of first planetary gears engaging with an outer surface of the sun gear; a second planetary gear which forms a concentric circle with each first planetary gear, and which is integrally formed with the first planetary gears; a first ring gear engaging with outer surfaces of the first planetary gears and connected to the output terminal; a second ring gear engaging with an outer surface of the second planetary gear; a cage for supporting rotary shafts of the first and second planetary gears such that the first and second planetary gears can revolve about the sun gear; and a brake member.

A vehicle transmission having a housing and a main transmission which includes input and output shafts and four planetary gearsets. Each of the gearsets has sun and ring gears, a carrier which supports a planetary gearwheel. The sun gear and the carrier of the second gearset are coupled permanently to the input and output shafts, respectively. The carrier of the second gearset is permanently coupled to the carrier of the fourth gearset. The ring gear of the second gearset is permanently coupled to the ring gear of the third gearset. The carrier of the fourth gearset can be coupled, via a first shifting element, to the sun gear of the second gearset. The carrier of the third gearset can be coupled, via a second shifting element, to the housing. The sun gear of the third gearset can be coupled, via third and fourth shifting elements, to the input shaft.

A vehicle control system configured to limit damage to an electric storage device even if a speed of a motor is changed abruptly. The control system includes a differential mechanism connected to an engine, a motor, and drive wheels, and a clutch. The control system includes a controller is configured to calculate an upper limit power possible to be applied or discharged to or from an electric storage device when a condition to engage the clutch is satisfied and restrict the electric power to be applied or discharged to or from the electric storage device when the electric power is equal to or less than a maximum allowable power that is less than the upper limit power before the clutch is engaged.

A first ring gear of a drive unit is connected to a second carrier and is mechanically connected to a counter shaft. A first sun gear is connected to a second sun gear and a first rotary electric machine. A first clutch selectively switches between a connection state and a disconnection state of the first sun gear and an engine. A second clutch selectively switches between a connection state and a disconnection state of a first carrier and the engine. A brake selectively switches between a fixed state and a release state of a second ring gear to and from a fixing member.

A motor vehicle group transmission with at least one housing, a main transmission and a range transmission connected downstream from the main transmission. The main transmission comprises at least four planetary gearsets, each of which comprises a sun gear, a carrier, a planetary gearwheel mounted on the carrier and a ring gear, and at least five shifting elements. The range transmission includes at least two planetary gearsets, each of which has a sun gear, a carrier, a planetary gearwheel mounted on the carrier and a ring gear, and at least three shifting elements. The main transmission and the range transmission, together in combination, provide at least thirteen forward gears and at least eight reverse gears.