Information about the Mirage CVT (Jatco CVT7 JF015E) operation, video, diagrams
The CVT in the Mirage is supplied by Jatco -- Japanese Automatic Transmission Company -- a subsidiary of Nissan (Wikipedia page / Corporate site). Production began in 2009 (source).
It's unique in that it's the first CVT with an auxiliary 2-speed gearbox. This gives the transmission the widest gear ratio (7.3 ratio spread) of any CVT, which offers both improved low RPM performance and greater efficiency at higher road speeds.
Source: Jatco’s next-gen CVTs bring high ratio spreads, more efficiency - 23-Apr-2012 - SAE International
The addition of the auxiliary gearbox allows the CVT to function more frequently in its most efficient 1:1 pulley ratio configuration. Traditional CVTs utilize only 1:1 pulley ratios for a brief period. In high gear the CVT7 is capable of maintaining this efficient condition during most normal driving conditions, the company claims.
Numerous additional improvements have gone into this transmission to improve efficiency relative to other CVT's. From the Jatco CVT7 page, "Jatco CVT7 CVT with an auxiliary gearbox for mini and small FWD vehicles JF015E" ...
By reducing the general thickness by using the optimum configuration and clearance of limits during production, a weightsaving of 22% was achieved compared with same class conventional CVT.
||The revolutionary-structure which combines of the belt CVT with an auxiliary transmission (two-step gear change) realizes the world's highest*2 transmission gear ratio, as well as enhanced responsiveness on starting and acceleration and improved quietness in high-speed driving.
||Reduction in pulley size, oil agitation resistance, etc. realize friction cut by 30% compared with conventional CVTs of the same class.
||The two-step gear change by an auxiliary transmission realizes smaller pulleys, reducing the overall length by 10% and weight by 13% compared with conventional CVTs of the same class.
The Mirage CVT also has "Idle Neutral Logic" which shifts the transmission to neutral while stopped to conserve fuel. See: CVT owners... what is "Idle Neutral Logic"? And what is it like to drive?
In addition, the CVT also has "hill start assist" so the car does not roll backward on a hill while moving your foot from the brake to the gas pedal when stopped.
The same CVT7 (though potentially with different programming) is also supplied to the Nissan Versa/Note, and will replace the inefficient slushbox stepped-gear automatic in the 2014 Chevrolet Spark in North America (in some other countries the Spark already has the CVT7). It's installed in a bunch of other cars, including cars in the Kei class in Japan (see list).
I'm not generally a fan of automatic transmissions, and I was prepared to dislike the Mirage's CVT. But I was genuinely pleasantly surprised when I test drove one last weekend. It's the first automatic I've driven that didn't feel like it was fighting against me while trying to get good fuel economy. See: Brief test drive: Mirage CVT and 5-speed (Donnelly Mitsubishi, Kanata/Ottawa, Canada)
Thread: How your CVT works
JATCO Eyes Global Expansion, Faces Down Strong Yen - May 24, 2012 Roger Schreffler | WardsAuto
Jatco starts up Thailand's first plant for CVT production - The Nation - September 11, 2013
View my fuel log 2014 Mirage base ES 1.2 manual: 54.0 mpg (US) ... 23.0 km/L ... 4.4 L/100 km ... 64.9 mpg (Imp)