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launch a new dual-clutch "automated" manual transmission dubbed "PowerShift." Codeveloped with its engineering partner, Getrag, a prototype six-speed unit was first shown to the public in 2004 in the Bronco Concept SUV. The production successor, also a six-speed, will be introduced this fall in Europe on turbodiesel versions of the Volvo S40/V50 and subsequently on a number of U.S. Ford models by the end of the decade. Ford claims the PowerShift gearbox has a mechanical efficiency of 80 percent, compared with a 68-percent figure for a typical four-speed automatic-sufficient to generate a fuel-economy savings of 10 percent. Equally promising, the basic design is adaptable to all types of vehicle/drivetrain configurations, and heavy-duty versions can already handle over 550 pound-feet of torque.

Less expensive to manufacture than a CVT and more compact than a traditional six-speed manual, this computer-controlled gearbox shares much common basic design with other dual-clutch systems, most notably, VW's original DSG unit. At its core is a hydraulically activated twin-clutch module that replaces the normal torque converter. This works in consort with a dual-layshaft architecture that places even-numbered gears on one shaft and odd-number gears on the other. Each set is activated by its corresponding clutch and ultimately sends power to a common output shaft. The "powershift" nomenclature refers to the manner in which this process occurs. Under acceleration, the system fully engages one gear while preselecting the next higher cog. At an optimum rpm/torque point, the electronic control unit executes a seamless changeover, disengaging one clutch as it engages the other to deliver a quick, smooth transition with virtually no interruption of power delivery. Like other dual-clutch systems, upshifting/downshifting can take place in full-auto mode or manually through the use of F1-style paddles.
 

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launch a new dual-clutch "automated" manual transmission dubbed "PowerShift." Codeveloped with its engineering partner, Getrag, a prototype six-speed unit was first shown to the public in 2004 in the Bronco Concept SUV. The production successor, also a six-speed, will be introduced this fall in Europe on turbodiesel versions of the Volvo S40/V50 and subsequently on a number of U.S. Ford models by the end of the decade. Ford claims the PowerShift gearbox has a mechanical efficiency of 80 percent, compared with a 68-percent figure for a typical four-speed automatic-sufficient to generate a fuel-economy savings of 10 percent. Equally promising, the basic design is adaptable to all types of vehicle/drivetrain configurations, and heavy-duty versions can already handle over 550 pound-feet of torque.

Less expensive to manufacture than a CVT and more compact than a traditional six-speed manual, this computer-controlled gearbox shares much common basic design with other dual-clutch systems, most notably, VW's original DSG unit. At its core is a hydraulically activated twin-clutch module that replaces the normal torque converter. This works in consort with a dual-layshaft architecture that places even-numbered gears on one shaft and odd-number gears on the other. Each set is activated by its corresponding clutch and ultimately sends power to a common output shaft. The "powershift" nomenclature refers to the manner in which this process occurs. Under acceleration, the system fully engages one gear while preselecting the next higher cog. At an optimum rpm/torque point, the electronic control unit executes a seamless changeover, disengaging one clutch as it engages the other to deliver a quick, smooth transition with virtually no interruption of power delivery. Like other dual-clutch systems, upshifting/downshifting can take place in full-auto mode or manually through the use of F1-style paddles.
Is the mechanical efficiency of a planetary trans really 60%?
 
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