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Researchers at the UC Davis HEV Center have developed a new design of a continuously variable transmission for use in all vehicle sizes. They have implemented this design by modifying a conventional pulley-type CVT both significantly increasing the efficiency and allowing for implementation in hybrid powertrains. The CVT is a pulley-type transmission in which a chain or belt is used to transmit torque from the input shaft to the output drive shaft. The hydraulically controlled pulleys allow for an infinite number of transmission ratios in a specified range, eliminating the need for discrete shifts. With drivability characteristics better than that of an automatic transmission and higher efficiency, the CVT is a considerable alternative. Modifications have been developed at UCDavis and Gear Chain Industries for conventional CVTs that increase the efficiency.

The objective of this paper is to indicate the design principals of a Continuously Variable Transmission that is physically about the size of a conventional manual transmission for the same power and torque with an equal or better efficiency and durability. The CVT will be designed for use in either a hybrid electric drive or a conventional vehicle with the addition of a torque converter and reverse gear. The design objectives are as follows: 1. About the same size as a 5 or 6 speed manual transmission for North-South engine orientation and rear wheel drive. 2. About the same weight as the 5 or 6 speed manual transmission 3. Cost about the same or less 4. Much smaller than a comparable performance rated automatic transmission 5. Fewer parts than manual transmissions and less than 1/30th of the part count of an automatic. 6. Ratio span greater than equivalent manual or automatic transmissions. 7.