| 摘要 |
A powertrain includes a continuously variable traction drive unit, a two-mode planetary gear set, and transfer gearing between the continuously variable unit (CVU) and the planetary gear unit. The planetary gear unit is essentially a four-node linkage mechanism having two members of each gear set interconnected. One member of one of the gear sets is connected to the CVU through a low range clutch and one of the interconnected members is connectable with the CVU through a high range clutch and another member is continuously connected with a prime mover, such as an engine. The planetary gear unit is controlled to provide a low mode that is controllable through the ratio of the CVU to establish a reverse range, a neutral condition, and a forward range. The planetary gear unit is also controllable to provide a high mode wherein the output the CVU and a mechanical path are combined at one gear set to provide a split drive, wherein a portion of the power is transmitted by the CVU and a portion of the power is transmitted by the more efficient mechanical path.
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