Eaton Launches Dual-Clutch Transmission
Marshall, MI — Eaton has introduced the Procision, a new medium-duty dual-clutch transmission. An automated manual gearbox — meaning two pedals only — the company claims it can deliver 8 to 10 percent better fuel economy than a similarly equipped vehicle with a torque-converter automatic. Production is scheduled to start mid-year in 2015 for North America, some time later for global markets.
It’s the first dual-clutch transmission built for class-6 and -7 applications, though Mitsubishi Fuso has offered one — the 6-speed Duonic — since 2012 in its Canter trucks up to class 5. Volvo has also developed the I-Shift 2, a dual-clutch version of its automated I-Shift transmission, making it the first manufacturer to install such a gearbox in a heavy-duty truck. It was introduced earlier this year, though not yet for North American sale. Several high-end cars also sport dual-clutch gearboxes these days.
Not incidentally, John Beering, Eaton’s senior vice president and general manager, Commercial Vehicle Transmission, says the Procision was conceived for applications from class 4 through 8 but he couldn’t provide a timetable for those other weight classes.
Initial class-6/7 application targets are pickup-and-delivery, towing, and beverage vehicles, plus school buses.
Eaton’s slick variation on the dual-clutch theme is a 7-speed that employs electronically controlled shifting, using grade, vehicle weight, and throttle input data to provide, in the company’s words, “optimal fuel efficiency and smooth, continuous delivery of torque under all shift conditions.”
After spending half a day driving the Procision in several different trucks at the Eaton Proving Grounds in Marshall, MI, I won’t argue with that word ‘smooth’. Shifts were seamless, up or down, sometimes nearly imperceptible because there’s no torque interruption.
Eaton says it employed dual-clutch technology to allow for more efficient acceleration from a stopped position and to optimize shift points that will efficiently get to the highest gear. Gear changes are made by swapping the engine torque between clutches with the next gear pre-selected.
“The highly efficient dual-clutch technology with a closed-loop control system significantly reduces slip and steady-state losses that are associated with torque-converter automatic transmissions,” said Jeff Carpenter, engineering manager for the medium-duty Procision.
The dual-clutch module is fully contained within the transmission, hydraulically controlled and oil cooled for extended life. A 5-spring damper is used to control torsional vibrations and is fully sealed to eliminate contamination.
Features such as Eaton Dynamic Shifting allow the transmission to automatically switch between economy and performance shift schedules based on mass, grade, and demand at the throttle. Base shift results are modified dynamically based on available torque, engine acceleration, and grade.
Economy and performance shift tables can be adjusted to tune an overall calibration to meet any customer’s specific needs, says Eaton, adding that this calibration flexibility is the most it’s ever offered.
Two key options seem likely to be popular. The adjustable ‘Creep Mode’ provides excellent low-speed maneuverability. As well, the adjustable ‘Hill Helper’ technology prevents roll-back or roll-forward for up to three seconds while on grades of up to 8 percent, allowing for a controlled launch. Uniquely, these features can be turned on and off using Eaton’s ServiceRanger software.
Procision comes standard with three power take-off (PTO) openings, also enabled via ServiceRanger software by dealerships after purchase.
The new transmission is fully integrated with Cummins Vehicle Acceleration Management.
Procision transmissions use a new synthetic lubricant that reduces maintenance costs thanks to 150,000-mile lube and filter change intervals. The internal sump filter and electrical system do not require maintenance.
The Procision’s design life is 10 years/400,000 miles and it comes with a three-year/unlimited mile warranty, which covers the complete system including the dual-clutch module, in commercial vehicle applications. School bus applications receive a five-year/unlimited mile warranty.
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