Abstract: A planetary gear train of an automatic transmission may include: an input shaft receiving torque of an engine; an output shaft transmitting torque to an output gear; a first planetary gear set including first, second, and third rotation elements; a compound planetary gear set including fourth, fifth, sixth, and seventh rotation elements; a fourth planetary gear set including eighth, ninth, and tenth rotation elements; a first shaft fixedly connected to the ninth rotation element and the input shaft; a second shaft fixedly connected to the second and sixth rotation elements and fixedly connected to the output shaft; a third shaft fixedly connected to the first and tenth rotation elements; a fourth shaft fixedly connected to the fourth rotation element; a fifth shaft fixedly connected to the fifth rotation element; a sixth shaft fixedly connected to the seventh rotation element; and a plurality of shafts selectively connected to a transmission housing.

Abstract: A power transmission apparatus includes: a planetary gear set configured to output a reduced speed or a same speed as a rotation speed of an engine; a first input shaft selectively connected to an engine output shaft through a first clutch; a second input shaft disposed on the outer circumference of the first input shaft and selectively connected to the engine output shaft through a second clutch; a third input shaft disposed in parallel with the first input shaft; an output shaft disposed in parallel with the first input shaft; an idle shaft disposed in parallel with the first input shaft; and a fixed transmission for selectively shifting torque input according to gear ratios of four speed gear trains. The four speed gear trains are disposed by externally connecting drive gears and driven gears to the first, second, and third input shafts, the output shaft, and the idle shaft.

Abstract: A planetary gear train of an automatic transmission is provided to improve power delivery and fuel efficiency by applying six engagement elements to four planetary gear sets to achieve multiple speeds. The planetary gear train includes: input and output shafts; first to fourth planetary gear sets respectively including first to third rotation elements, fourth to sixth rotation elements, seventh to ninth rotation elements, tenth to twelfth rotation elements; and first to eighth shafts. In particular, the first shaft is fixedly connected to the second, sixth and eleventh rotation elements and the input shaft, the fourth shaft is fixedly connected to the fourth, seventh and tenth rotation elements, and the seventh and eighth shafts selectively and respectively connect a transmission housing to corresponding rotation elements of the first and third planetary gear sets, and the corresponding rotation elements are not connected to any shaft among the first to sixth shafts.

Abstract: A planetary gear train of an automatic transmission for a vehicle provides at least ten forward speeds and one reverse speed by combination of: first to fourth planetary gear sets respectively having first to third rotational elements, fourth to sixth rotational elements, seventh to ninth rotational elements, or tenth to twelfth rotational elements; first to ninth shafts; and multiple control elements including four clutches and three brakes. In particular, each of the tenth, eleventh, twelfth rotational elements is fixedly connected with a different shaft selected from the first, sixth, seventh and ninth shafts, and one clutch is fixedly connected with the ninth shaft.

Abstract: A planetary gear train of an automatic transmission for a vehicle improves power delivery and fuel efficiency by applying six control elements to four planetary gear sets to achieve forward nine speed stages and one reverse speed stage. The planetary gear train includes: an input shaft; an output shaft; first to fourth first planetary gear sets each having three rotational element: four clutches and two brakes as the six control elements; and first to ninth shafts. In particular, the first shaft connects a first rotational element and the input shaft; the second shaft is connected with a second rotational element and selectively connected with the first shaft; the third shaft connects third and fifth rotational elements; the fourth shaft is connected with a fourth rotational element and fixed to a transmission housing; and the fourth shaft is connected with the fourth rotational element and fixed to the transmission housing.

Abstract: Ten or more forward speeds and two or more reverse speed are achieved by a planetary gear train of an automatic transmission that includes three planetary gear sets mounted on an input shaft, an output shaft disposed in parallel with the input shaft and having an output gear. The transmission further includes six shafts respectively interconnecting corresponding elements among the input shaft and rotational elements of the three planetary gear sets, a first transfer gear selectively delivering torque between one of the six shafts and the output shaft; and a second transfer gear selectively delivering torque between the output shaft and one rotational element of the third planetary gear set.

Abstract: A power transmission apparatus for a vehicle is disclosed. The power transmission apparatus includes a first input shaft selectively connected to an engine output shaft through a first clutch, a second input shaft configured as a hollow shaft that is disposed on the outer circumference of the first output shaft without rotational interference and selectively connected to the engine output shaft through a second clutch, a third input shaft configured as a hollow shaft that is disposed on the outer circumference of the second output shaft without rotational interference and selectively connected to the engine output shaft through a third clutch. The transmission apparatus further comprises an output shaft placed parallel to the first, second, and third input shafts at a certain distance.

Abstract: A power transmission apparatus for a vehicle may include: a first, second, third, and fourth input shaft; an output shaft; an idle shaft; a fixed transmission performing shifts to fixed shift stages depending on gear ratios of four change gear trains; and a torque assist driving and electronic continuously variable automatic transmission performing a torque assist for a torque input from the fixed transmission and performing electric vehicle driving and electronic continuously variable automatic transmission functions to output the torque through the output shaft. The disclosed power transmission apparatus implements fixed shift stages of four forward speeds and one reverse speed in a dual clutch transmission (DCT) structure that uses three synchronizers.

Abstract: A planetary gear train may include input and output shafts, first to fourth planetary gear sets having first to third, fourth to sixth, seventh to ninth, and tenth to twelfth elements, a first shaft fixedly connected to the fourth and tenth elements, and selectively connectable to the input shaft, a second shaft fixedly connected to the third element, and selectively connectable to the input shaft, a third shaft fixedly connected to the eleventh element the output shaft, a fourth shaft fixedly connected to the first, sixth, and ninth elements, a fifth shaft fixedly connected to the eighth and twelfth elements, and a plurality of shafts each of which is selectively connectable to the transmission housing and fixedly connected to an element of the first, second and third planetary gear sets which is not fixedly connected to any of the first to seventh shafts.

Abstract: The present disclosure provides a hydraulic control system for an automatic transmission. The system includes: a linear solenoid valve configured to control a line pressure and to supply the line pressure to a coupling element, a shift valve to which an output hydraulic pressure of the linear solenoid valve is supplied, and a transmission control unit configured to control the shift vale and the linear solenoid valve.

Abstract: A planetary gear train may include input and output shafts, first to fourth planetary gear sets respectively having first to third, fourth to sixth, seventh to ninth, and tenth to thirteenth elements, a first shaft connected to the second element and the input shaft, a second shaft connected to the eleventh element and the output shaft, a third shaft connected to the first and seventh elements, a fourth shaft connected to the fifth and twelfth elements, a fifth shaft connected to the eighth and tenth elements, a sixth shaft connected to the thirteenth element, and a plurality of shafts each selectively connecting a corresponding element to a transmission housing, the corresponding element being an element of the first, second and third planetary gear sets which is not interconnected.

Abstract: A planetary gear train is provided. The gear train includes input and output shafts and first to fourth planetary gear sets that respectively have first to third, fourth to sixth, seventh to ninth, and tenth to twelfth elements. A first shaft is connected with the first and fourth elements and selectively connected with the input shaft, a second shaft is connected with the sixth element and selectively connected with the input shaft, a third shaft is connected with the eighth element and the output shaft, a fourth shaft is connected with the second, fifth, and ninth elements, and a fifth shaft is connected with the third and eleventh elements. A plurality of shafts are each selectively connected to the transmission housing and connected to an element of the third and fourth planetary gear sets that is not connected with any of the first to seventh shafts.

Abstract: A power transmission apparatus for a vehicle may include: a first, second, third, and fourth input shaft; an output shaft; an idle shaft; a fixed transmission performing shifts to fixed shift stages depending on gear ratios of four change gear trains; and a torque assist driving and electronic continuously variable automatic transmission performing a torque assist for a torque input from the fixed transmission and performing electric vehicle driving and electronic continuously variable automatic transmission functions to output the torque through the output shaft. The disclosed power transmission apparatus implements fixed shift stages of four forward speeds and one reverse speed in a dual clutch transmission (DCT) structure that uses three synchronizers.

Abstract: A planetary gear train may include input and output shafts, first to third planetary gear sets respectively having first to third, fourth to sixth, and seventh to ninth elements, a first shaft connected to the second element and the input shaft, a second shaft connected to the sixth and eighth elements and the output shaft, a third shaft connected to the third and seventh elements, a fourth shaft connected to the fourth element, and a plurality of shafts each selectively connecting a corresponding element to a transmission housing, the corresponding element being an element of the first, second and third planetary gear sets which is not interconnected.

Abstract: A planetary gear train may include: an input shaft an output shaft; first to fourth planetary gear sets including first to twelfth rotation elements; a first shaft fixedly connected to the second rotation element and the input shaft; a second shaft fixedly connected to the ninth and tenth rotation elements, and selectively connectable to the input shaft; a third shaft fixedly connected to the eleventh rotation element and the output shaft; a fourth shaft fixedly connected to the third rotation element; a fifth shaft fixedly connected to the fifth rotation element, the eighth rotation element, and the twelfth rotation element; a sixth shaft fixedly connected to the seventh rotation element; and a plurality of shafts formed by combinations of remaining rotation elements of the first and second planetary gear sets that are not connected to the first to sixth shafts, and selectively and respectively connected to a transmission housing.

Abstract: A planetary gear train may include input and output shafts, first to third planetary gear sets respectively having first to third, fourth to sixth, and seventh to ninth elements, a first shaft connected to the second element and the input shaft, a second shaft connected to the sixth and eighth elements and the output shaft, a third shaft connected to the third and seventh elements, a fourth shaft connected to the fourth element, and a plurality of shafts each selectively connecting a corresponding element to a transmission housing, the corresponding element being an element of the first, second and third planetary gear sets which is not interconnected.

Abstract: A planetary gear train may include input and output shafts, first to fourth planetary gear sets respectively having first to third, fourth to sixth, seventh to tenth, and eleventh to thirteenth elements, a first shaft connected to the second element and the input shaft, a second shaft connected to the twelfth element and the output shaft, a third shaft connected to the first and seventh elements, a fourth shaft connected to the eighth element, a fifth shaft connected to the ninth and eleventh element, a sixth shaft connected to the fifth and thirteenth elements, and a plurality of shafts each selectively connecting a corresponding element to a transmission housing, the corresponding element being an element of the first, second and third planetary gear sets which is not interconnected.

Abstract: A planetary gear train includes input and output shafts, first to fourth planetary gear sets respectively having first to third, fourth to sixth, seventh to ninth, and tenth to twelfth elements, a first shaft connected with the fifth rotational element and the input shaft, a second shaft connected with the ninth and tenth elements, and selectively connected with the input shaft, a third shaft connected with the eleventh element and the output shaft, a fourth shaft connected with the second and twelfth elements, a fifth shaft connected with the sixth elements, a sixth shaft connected with the seventh element, a seventh shaft connected with the eighth element, and a plurality of shafts each selectively connecting a corresponding element to a transmission housing, the corresponding element being an element of the first and second planetary gear sets that is not interconnected.

Abstract: A planetary gear train of an automatic transmission for a vehicle is disclosed. A planetary gear train of claim of an automatic transmission for a vehicle, includes an input shaft for receiving an external torque; an output shaft for outputting a shifted torque; a first planetary gear set having first, second, and third rotational elements; a second planetary gear set having fourth, fifth, and sixth rotational elements; a third planetary gear set having seventh, eighth, and ninth rotational elements; a fourth planetary gear set having tenth, eleventh, and twelfth rotational elements; a first shaft fixedly connected with the second rotational element, the sixth rotational element, the seventh rotational element, and the input shaft; a second shaft fixedly connected with the eleventh rotational element, and the output shaft; and a third shaft fixedly connected with the first rotational element and the tenth rotational element.

Abstract: A planetary gear train may include input and output shafts, first to fourth planetary gear sets respectively having first to third, fourth to sixth, seventh to ninth, and tenth to twelfth elements, a first shaft connected to the first, sixth, and seventh elements, and selectively connected to the input shaft, a second shaft connected to the ninth element and selectively connected to the input shaft, a third shaft connected to the eleventh element and the output shaft, a fourth shaft connected to the third and fourth elements, a fifth shaft connected to the fifth, eighth, and twelfth elements, and a plurality of shafts each selectively connecting a corresponding element to a transmission housing, the corresponding element being an element of the first and fourth planetary gear sets which is not interconnected.