To improve efficiency of a transmission of a vehicle in running at high speed.
A continuously variable transmission 14 capable of changing a gear ratio in a continuously variable manner and a stepwise variable transmission 16 capable of changing a gear ratio from among a plurality of change gear ratios are series-coupled to each other. When a vehicular speed V detected by a vehicular speed sensor 44 is not more than a given speed V0, an electronic control unit 42 couples directly an input and output of the stepwise variable transmission 16 to control a change gear ratio γcvt of the continuously variable transmission 14 based on the vehicular speed V as well as fixing the change gear ratio γat of the stepwise variable transmission 16 to 1. On the contrary, when the vehicular speed V is higher than the given speed V0, the electronic control unit 42 fixes the change gear ratio γat of the stepwise variable transmission 16 to a change gear ratio lower than 1 and besides increases the change gear ratio γcvt of the continuously variable transmission 14 to a change gear ratio higher than that when the vehicular speed V0 is the given speed. Thus, a change gear ratio is controlled so as to make drive train efficiency ηcvt high-efficiency.
COPYRIGHT: (C)2007,JPO&INPIT
TARUYA ICHIRO
NAKAZAWA TERUHIKO
| JPS61241561A | 1986-10-27 | |||
| JPH11299005A | 1999-10-29 |
Jun Ishida