Lift axle, powertrain specs net fuel savings for cement hauling

Mack Trucks has added the 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 vehicles47 Mackv 400
tend to haul out heavy and return empty.

The Load Logic technology and 6×2 spec monitor tanker or trailer weight and adjust the truck’s driveline configuration to boost fuel efficiency 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 as a direct drive transmission, 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.

47 Mackvi 400

Sensors and software equip Load Logic to adjust driveline configuration for optimal fuel economy. The technology switches the mDRIVE automated manual transmission from direct drive for a fully loaded trailer to overdrive when empty. Mack engineers tailored the 6×2 liftable pusher axle with their peers at Link Manufacturing.

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 efficiency 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. Optimized Traction, a default setting, 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 with which a driver can raise or lower the suspension for easier landing gear retraction or tanker/trailer hook-up, respectively. —