Nissan Motor Co. is planning a fourfold increase in vehicles fitted with CVT (continuously variable transmission) over the next three years, according to a report last week in Automotive News and a news release from the company. Reaching that goal requires Nissan to increase by seven times the number of CVT-equipped vehicles it sold in the United States in 2004, assuming that its sales don't drop dramatically. In fiscal year 2007, Nissan plans to sell around 1 million CVT-fitted models worldwide, up from an estimated 250,000 this fiscal year. This will raise the proportion of CVT-fitted vehicles to around 24 percent of global sales volume, up from seven percent at present.General Motors discontinued its CVT, used in the Saturn Ion and Vue, after the 2004 model year. A CVT is standard equipment on the 2005 Ford Freestyle and optional on the 2005 Ford Five Hundred, but availability of the transmission has been limited. Audi offers a CVT on its A4 line.Currently, the Murano SUV is the only Nissan or Infiniti vehicle equipped with a CVT sold in the U.S. market. A CVT is standard equipment on the Murano, mated to a 3.5-liter V-6 that produces 245 horsepower.Continuously variable transmissions can improve fuel economy seven to 11 percent, according to General Motors. One limiting factor has been the amount of engine torque the transmission's metal belt can handle, but improvements in the technology have allowed automakers to use the transmission on bigger engines, the report said.