In a move that Freightliner Trucks says is a first for the industry, it will begin offering rack and pinion steering as an option on Century Class S/T, Coronado, Columbia, Classic, and Classic XL Class 8 trucks late in 2006. Rack and pinion steering is said to be lighter, have fewer moving parts than integral gear steering, and provide better control and steering responsiveness.
Freightliner showed the new system at the Mid-America Trucking Show. On vehicles with spring suspensions, the rack and pinion system weigh 45 lb less than conventional gear steering. With fewer parts and pivot points, rack and pinion steering controls front wheel direction more accurately, Freightliner says, while enhancing driveability and increasing the operator's feeling of control.
The idea to equip heavy highway tractors with rack and pinion steering came from Freightliner engineers involved with truck racer Mike Ryan's Pikes Peak hill climb truck. The same qualities needed to drive at top speed up a mountain are the same ones needed to negotiate traffic and tight dock areas, says Jonathan Randall, director of product engineering at Freightliner.
Rack and pinion steering has two main components, a horizontal rack with gear teeth and an intersecting pinion with a toothed wheel. Turning the steering wheel rotates the pinion, causing the rack to move left or right as required. The new steering system made its show debut in two Freightliner trucks, a Century Class S/T highway tractor and a Columbia daycab.
In other Freightliner developments, the company announced the availability of the Bergstrom NITE (No-Idle Thermal Environment) climate control system for heavy trucks with sleepers. The Bergstrom system has two components, a battery powered air-conditioner for cooling and a diesel-fired heater. A pack of four deep-cycle batteries power a hermetically sealed air-conditioner that provides 3,500 Btu/hr cooling capacity. The unit draws no power from the truck electrical system when the engine is shut down, but recharges its batteries from the alternator during normal highway operation.
The heater uses diesel fuel to generate from 2,900 to 7,500 Btu per hour at a consumption rate of less than one-tenth gallon per hour. The entire system adds only 345 lb to total vehicle weight.
Freightliner has begun to deliver test trucks equipped with engines that meet the 2007 exhaust emission standards to fleet customers. Freightliner, Sterling, and Western Star trucks will be available with engines from Detroit Diesel, Mercedes-Benz, and Caterpillar.