Volvo piles on the power
Feb 1, 2005 12:00 PM
Volvo Trucks North America has announced a new highway tractor powered by what Volvo claims to be the most powerful truck engine in North America. Set atop its product line, the new VT 880 is aimed directly at the owner-operator and other premium tractor users market.
To meet the desire for classic truck appearance from owner-operators, the VT 880 is a longnose conventional tractor that measures 200 inches from the bumper to the back of the integral 77-inch sleeper berth. Independent operators often say that a long hood is essential for true “big truck” appearance. To achieve this, the cab has been moved back on the chassis by eight inches compared to previous Volvo cab mountings. To make the VT 880 look even more aggressive, the front axle has been moved forward by 12.4 inches compared to other Volvo tractors. These two changes help to isolate the engine from the cab for a quieter, smoother ride, Volvo says. Moving the cab and front axle produces an engine mounting position for maximum airflow through the cooling system while providing an axle position that allows a 45° wheel cut for easy maneuverability.
Inside the VT 880, the sleeper has 374 cubic feet of space that combines with the operator's compartment for a total cab volume of 520 cubic feet. The tractor comes with a premium interior trim package not available on other Volvo trucks.
The new tractor is designed specifically for high horsepower engines. Optional power plants from Cummins in the ISX line range from 475 to 565 hp. However, the VT 880 was designed around Volvo's newest engine, the D16, a 16-liter six-cylinder. In English units, the D16 displaces a massive 976 cubic inches. At the top of its horsepower and torque range, the D16 produces 625 hp and 2,250 lb/ft torque. Other versions produce 500 or 525 hp at 1,850 lb/ft torque or 600 hp at 2,050 lb/ft torque.
All that torque could be deadly to drivelines at low speeds in low gear. To protect drivelines, Volvo has equipped the D16 with a new technology called Intelligent Torque that limits torque output at low speed. In the startup gears, the engine produces only 1,650 lb/ft torque with output increasing to 1,850 lb/ft as speed increases for the 500 or 525 hp versions. Engines producing 600 or 625 hp have two torque output phases before reaching maximum power.
An integrated engine compression brake provides 335 hp of braking power at 1,500 rpm. Volvo says its engine brake is not as altitude-sensitive as some other brakes.
Displacement of the D16 is achieved by using large cylinder bores rather than increasing the stroke of an existing engine design. This provides a large top surface on the piston, which Volvo says generates more power at lower forces inside the engine. The short stroke design produces less engine wear, because pistons travel a shorter distance with each engine revolution. The D16 block is longer than other Volvo engines, providing more space between the cylinder bores for a stronger block that runs at more consistent temperature.
The D16 has a rear-mounted gear train to drive the camshaft, air compressor, and power steering pump. The camshaft is dampened to reduce vibration. The cam can be lifted up and out of the engine without removing the radiator or removing the engine from the tractor.
Development work to meet emission standards was done in the US, so the D16 meets current standards and is designed with the 2007 standards in mind. Design work also considered the more stringent standards scheduled to go into effect in 2010.
Volvo says the D16 engines are designed for operators who want to maintain high average legal speeds while running in mountainous terrain at full gross weight. According to Volvo, a VT 880 combination loaded to 80,000 lb can maintain 65 mph at 1,400 rpm on a 3% grade without changing gears. The D16 is available only in the VT 880.
The VT 880 and the D16 engine can be ordered now for initial deliveries in June 2005 from production beginning in April. Full production will be available in the fourth quarter 2005.
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