Volvo Trucks North America will bring a completely re-designed version of the I-Shift automated mechanical transmission built by its Swedish parent AB Volvo for trucks to the U.S. in the second quarter of 2007.
Unveiled at a special ride-and-drive event held by Volvo in Savannah, GA, the U.S.-version of the I-Shift has been designed to specifically mesh with the company's line of '07-compliant engines — the D-11, D-13, and D-16 — to get the best fuel economy possible, while allowing a truck driver to either drive completely in automatic mode or have manual shift control without the need for a clutch pedal.
Scott Kress, senior vp-sales & marketing, said Volvo would offer three I-Shift models, with the ability to handle all power and torque inputs from its new engine family, including the top 600 hp./2,050 lb.-ft. rating. The OEM plans to make the transmission available for all Volvo truck models, including the VN and VT highway tractors, and the VHD vocational truck.
Bo Hammerlind, Volvo's product marketing manager, said the I-Shift is a 12-sp. single counter-shaft transmission built up with a splitter, with a main section that has three forward and one reverse gear, plus a range gear.
As an automated mechanical transmission, the I-Shift does not use synchronizers in its main section and thus doesn't require a clutch pedal. The I-Shift weighs between 597 and 610 lb.
“We've focused on two key points with I-Shift: maximizing fuel economy across all trucking conditions while improving driver comfort by not having to manually shift all the time,” Hammerlind said.
The I-Shift is programmed with Volvo's engine efficiency map for each engine rating, working with special road sensors to continuously calculate the vehicle's speed, acceleration, torque demand, weight, rolling and air resistance, and road grade in 30-second intervals to optimize engine performance and fuel economy.
One of the I-Shift's special features is a system called Eco-Roll, which automatically disengages the engine when the vehicle is in top gear on long, slight downgrades that require no engine torque input. By allowing the engine to idle in these situations, Eco-Roll can reduce parasitic losses by as much as 30 hp. and thus conserve fuel, Hammerlind noted.
“But the biggest benefit is safety. I-Shift keeps the driver's hands on the wheel and eyes on the road, while relieving the inexperienced driver of the challenge of selecting and shifting into the correct gear,” he said. “The driver can always concentrate on what is happening around him in traffic…while also reducing the work and fatigue brought on by continuous shifting — especially in traffic congestion.”