Nissan Motor Co. has been on a tear, boosting fuel economy across its product lines, and Takashi Hata's Jatco Ltd. gets a big piece of the credit. Engineers led by Hata, 54, have delivered a new generation of continuously variable transmissions that make CVTs attractive, even for larger cars and luxury vehicles. Jatco and Nissan redesigned 70 percent of the parts on the transmissions in a campaign to reduce 40 percent of the operating friction. Jatco also expanded the transmission's gear ratios so that the new Nissan Altima and Sentra can boast better fuel economy and less engine noise. The achievement cleared the way for CVTs to go into the new-generation Nissan Pathfinder and even the luxury Infiniti JX. Hata's results send a message to the industry that the once-decried CVT is now a legitimate benchmark in the push for fuel economy.