Mack’s optimized lift axle, powertrain specs spell cement hauling fuel economy

Sources: Mack Trucks, Greensboro, N.C.; CP staff

Mack Trucks has unveiled a sensor technology, Load Logic, and 6×2 liftable pusher axle option for its Pinnacle highway tractor, citing the potential for fuel efficiency and driver productivity improvement in cement and other bulk material deliveries, where vehicles tend to haul out heavy and return empty.

The Load Logic and 6×2 spec combine to monitor tanker or trailer weight and adjust the truck’s driveline configuration to lower fuel consumption without impacting performance. The former integrates an advanced sensor in the rear suspension with the Mack mDRIVE automated manual transmission. Upon detecting a fully loaded trailer, mDRIVE operates in direct drive mode, locking out the 12th gear for increased pulling power. When an empty trailer is detected, the transmission switches to overdrive, enabling the 12th gear to lower cruise RPMs and maximize fuel efficiency.

The 6×2 with liftable pusher axle is also capable of determining payload by using sensors in the rear suspension and either lifting or lowering the foremost rear axle. When an empty load is detected, the axle lifts, allowing the tractor to operate as a 4×2 for less drag, better fuel economy and reduced tire wear. For full loads, the same axle is lowered to provide additional stability and distribution of the trailer’s weight on the fifth wheel.

To deliver optimal traction, the system’s suspension pressure and ride height are continuously monitored and adjusted to maintain a load bias toward the drive axle. Three driver-selectable control modes are available via a dash-mounted switch. Enhanced Traction augments low-speed operation for improved starts, docking and slippery road conditions. A default setting, Optimized Traction maximizes load to the drive axle; if wheel slip is detected, the system can increase load to the drive axle for 30 seconds to improve traction. A Basic Traction setting lowers the lift axle regardless of suspension load and maintains a 50/50 load split between the lift and drive axles during loading or unloading, prolonged stops or areas that require such balance between tandem axles.

During normal operation, automatic lift axle control is based on payload. The system offers a manual control feature that enables a driver to raise or lower the suspension for easier landing gear retraction or tanker/trailer hook-up, respectively. —