Transmission characteristic of a new type of power transmission unit that is proposed by the author is analyzed in different working condition. The unit can switch from single-degree-of-freedom mode to two-degree-of-freedom mode

which accommodates the requirements of hybrid vehicles. Especially

it also can help to start the vehicle and shift the gear peacefully without torque converter or main clutch in the power train. Different means are proposed to fit different drive condition

such as single engine drive

single ISG drive

parallel hybrid drive

break regeneration

engine start

torque control during vehicle start and gear shift

etc. Accordingly

the relationship of kinematics and dynamics in each drive condition also is analyzed.