Moving decisively to produce a vehicle package that incorporates the new EPA '02 engines, Sterling Truck Corporation has introduced a new chassis for its A- and L-line trucks and tractors. Designated the HX chassis, the new design replaces the HN80 chassis from earlier Sterling models.
The HX chassis is the result of a need to upgrade cooling capacity in all Sterling trucks to accommodate the new engines, Landon Grogan, program manager for the HX project, said. In addition to changing the cooling system, the HX has a new design for the front of the frame, new front suspension, and enhanced steering. While making these changes, Sterling has produced strong, lightweight frames, a new proprietary cab air suspension, and new fuel tank options.
The new cooling system uses an aluminum radiator core with vacuum-brazed tubing. The cross flow radiator is available in 1,000-, 1,200-, or 1,400-sq inch sizes. The 1,200- and 1,400-sq inch radiators have the capacity to handle the cooling requirements of engines up to 500 horsepower. Cab positioning has been adjusted to provide room for the larger radiators. The new design braces the radiator to the cab and uses narrow-based radiator isolators for increased strength. Radiator mounting is the same for all three BBC lengths — 101, 111, and 113 inches — in the Sterling line. The new cooling system is specific to the Sterling product line; although, the radiator cores are the same as those in other Freightliner Corporation products.
The cab is the same as previous Sterling trucks. The design is only five years old and is well accepted by the company's customer base, officials said. Instead of introducing a new cab appearance to go with the new chassis, Sterling chose to maintain product continuity for customers.
In addition to changing the cooling system, Sterling made extensive changes to the frame of the new HX chassis. In addition to the 10- and 11-inch frame sections from previous Sterling chassis, the HX also offers a new 13-inch frame section. The frame is built with five-piece welded cross members. All frame reinforcements are now a 1/4-inch C-channel installed inside the frame to provide a consistent frame rail height and frame width. Sterling's previous practice of reinforcing the frame with an exterior channel, an outsert, caused some difficulty for body builders. With inserts, the new HX frame can provide a resistance bending moment of up to 5 million inch-pounds.
The new frames are produced with Sterling's “Optilock Chassis Grid System” that standardizes the layout used for punching holes in the frame. The grid system provides five rows of potential hole locations, each spaced roughly two inches apart. All frame components mount within this grid pattern. In addition, Sterling can pre-punch the frame for bodies and equipment to be mounted later.
New power steering
Standard power steering now is a high-pressure system from TRW. It includes a two-quart see-through fluid reservoir.
Front axle and suspension options are available up to 20,000 lb with composite springs as an option. In the setback front axle configuration, Freightliner's Airliner combination air and leaf spring suspension rated at 12,000 lb is available.
Fuel tank options have been simplified for the new HX chassis. The Sterling standard now is a 23-inch diameter cylindrical aluminum tank with an option for a 25-inch diameter. Tank capacity ranges from 50 to 150 gallons. Tanks are mounted with cast aluminum brackets for lighter weight. On most trucks, fuel tanks are mounted to the frame under the cab so that the frame is clear from the back of the cab all the way to the rear.
Scroll air-conditioning compressor
In addition to changes made for the new engines, Sterling used the HX announcement to introduce a new air-conditioning compressor. Beginning in 2004, Sterling trucks will offer a scroll compressor from Visteon as standard equipment. The new compressor, which has only two moving parts, has been adapted for heavy truck use from a compressor used for years in luxury automobiles. The two scroll elements are forged aluminum and designed specifically for heavy-duty applications. The entire compressor package, including the clutch, weighs just over 14 lb. In addition to durability and reliability, scroll compressors have the lowest power demand of any automotive air-conditioning compressor, Sterling says. The new compressor carries a two-year warranty.
The HX chassis project was started 18 months ago and will go into production in November 2003. Chassis rollout is timed to coincide with engine availability. The first HX chassis in November will have Caterpillar engines. Sterling trucks with Detroit Diesel engines will be available in the first quarter of 2004. The last step in the HX rollout will be Mercedes-Benz engines in the second quarter of 2004.
Sterling used the introduction of the HX chassis to celebrate the production of the 100,000th truck at its plant in St Thomas, Ontario, Canada. All conventional cab Sterling products are manufactured in St Thomas. The celebratory truck was delivered to USF Holland, a regional LTL carrier based in Holland, Michigan.
The St Thomas plant was originally started in 1991 to build Freightliner trucks. At first, the plant had 259,000 sq ft of manufacturing space and produced 18 trucks a day on one shift. After Freightliner acquired the rights to Ford's heavy truck designs and inventory in 1997, the plant was expanded to 416,000 sq ft and dedicated to building the Sterling product line early in 1998 with a daily production of 76 trucks. Today the plant covers 444,000 sq ft and has 1,200 employees. Although production has slowed slightly, the St Thomas plant has built as many as 111 trucks per day in its five years for Sterling.
Rainer Schmueckle, president and chief executive of Freightliner, said that Sterling is a key component of Freightliner's goal of being the leading commercial vehicle vendor in North America from a network of 400 dealers. The target for Sterling is to hold 10% of the Class 8 vehicle market. He said the company is dedicated to serving the regional, short haul, and vocational markets as well as truckload carriers. As a part of reaching its goals, Freightliner has invested more than C$500 million in the St Thomas plant.
In addition to Terry Bruni, St Thomas plant manager, John Merrifield, senior vice-president, sales & marketing for Sterling; Jeff Kohler, mayor of the city of St Thomas; and Buzz Hargrove, national president of the Canadian Auto Workers, took part in the celebration.