Nissan's next generation CVT claims world's highest transmission ratio
By Jeff Salton
July 30, 2009
Nissan and its transmission supplier Jatco have jointly developed a next generation CVT (continuously variable transmission) that promises better fuel economy and performance in a compact and lightweight package. The new CVT combines conventional CVT belt operation with an auxiliary gearbox and has a significantly increased gear ratio range – roughly 20 percent higher than other CVTs and among the world's highest for production vehicles according to Nissan.
The 7.3:1 ratio (up from 6.0:1) is higher than the average conventional seven-speed automatic transmissions used on high-displacement engine-equipped compact and lightweight vehicles. The new CVT features Adaptive Shift Control (ASC), which improves performance by automatically selecting the best ratio for startup, acceleration and uphill or downhill driving.
The configuration combines a typical belt-operated CVT with an auxiliary transmission for the top gear. It is also shorter by 10 percent and 13 percent lighter compared to conventional CVTs in its class. Lighter components, in particular, usually equate to better fuel economy, which the company is aiming for as well as improved performance.
Nissan’s corporate vice president, Nissan Powertrain Engineering Division, Shuichi Nishimura says: "Nissan believes the CVT has very good potential as a leading technology for raising the fuel efficiency of internal-combustion engine systems." He added: "Nissan first began applying CVT technology in 1991 and has been continuously evolving CVTs, engine-cooperative management and other systems, and expanding their use in Nissan vehicles. The need to improve fuel economy, with the resulting reductions in CO2 emissions motivated us to step up our efforts in the joint development with Jatco of this next-generation CVT."
Jatco’s vice president, Yo Usuba, says Jatco is the producer of 43 percent of the world’s CVTs, and is the only company that offers a full range of CVTs for applications from mini-vehicles up to 3.5-liter V6-equipped cars.
"The revolutionary structure of the next-generation CVT, with its auxiliary transmission, not only raises the transmission ratio, reduces weight and adds fuel efficiency, its compact design also expands its applicability to a broader range of vehicles," he says. "We believe it is an excellent choice for automakers seeking to raise the fuel efficiency of their smaller cars."
Together, Nissan and Jatco have sold of 1 million CVT-equipped vehicles, as well as introducing seven-speed automatic transmissions to improve fuel efficiency.
The company says we can expect to see the new CVT in compact Nissan vehicles worldwide in "the near future".[youtube:ABaJidk9SJA&hl=en&fs=1&]