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Adrian PatonFord's PowerShift dual-clutch gearbox
January 22nd 2009 04:30
Ford has become the latest car maker to introduce a dual-clutch gearbox to its lineup in North America starting with the small-car segment in 2010. Dubbed PowerShift, the six-speed dual-clutch gearbox is essentially two manual transmissions working in parallel, each with its own independent clutch unit. One clutch carries the odd gears - 1, 3 and 5 - while the other takes of the even gears – 2, 4 and 6 - and reverse.
"PowerShift represents a true competitive advantage for Ford and is one of the many technologies that will help our global small-car platforms set a new world standard for efficiency and drive quality," said Barb Samardzich, vice president, Global Powertrain Engineering.
"This advanced six-speed is an improvement over today's automatic transmissions in terms of fuel economy, while providing customers an even more fun-to-drive experience."
"This advanced six-speed is an improvement over today's automatic transmissions in terms of fuel economy, while providing customers an even more fun-to-drive experience."
In North America, a dry-clutch derivative of Ford's PowerShift transmission will be used for added efficiency and durability - as opposed to the wet-clutch system used in the European Ford Focus. A dry clutch transmits power and torque through manual transmission clutch facings, while most automatic transmissions utilize wet clutch plates submerged in oil. Consequently, the dry-clutch PowerShift transmission does not require an oil pump or torque converter, providing superior mechanical efficiency.
"A dry clutch is a real sweet spot for lighter vehicle applications," said Piero Aversa, manager, Ford Automatic Transmission Engineering.
"PowerShift is more efficient, it saves weight, is more durable, more efficient and the unit is sealed for life, requiring no regular maintenance."
"PowerShift is more efficient, it saves weight, is more durable, more efficient and the unit is sealed for life, requiring no regular maintenance."
Unique driving features for the PowerShift gearbox includes:
• Neutral coast down – The clutches will disengage when the brakes are applied, improving coasting downshifts and clutch robustness as well as reducing parasitic losses for increased fuel economy.
• Precise clutch control in the form of a clutch slip to provide torsional damping of the engine vibration – This function improves noise, vibration and harshness (NVH) at low engine speeds and enables lower lugging limits for improved fuel economy.
• Low-speed driving or creep mode with integrated brake pressure – This function simulates the low-speed control drivers are accustomed to from an automatic transmission. The amount of rolling torque in Drive and Reverse is precisely controlled, gradually building as brake pressure is released.
• Hill mode or launch assist – Prevents a vehicle from rolling back on a grade by maintaining brake pressure until the engine delivers enough torque to move the vehicle up the hill, providing improved driver confidence, comfort, safety and clutch robustness.
• Reduces fuel consumption by up to 9 percent depending on the application.
[Source: Ford]
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