New engines and transmissions for medium-duty truck applications are evolving rapidly in response to ongoing demands for improved fuel consumption. Software is playing a major role in these advances while also helping improve diagnostic capabilities. Several manufacturers revealed their new wares at the recent Work Truck Show in Indianapolis.

Algorithms were the primary tool when Allison Transmission upgraded its FuelSense software to FuelSense 2.0, which features DynActive Shifting. It’s an evolution from table-based shifting that boosts fuel consumption by up to 6%.

“DynActive Shifting has a learning algorithm that handles shift scheduling,” said Ryan Milburn, Executive Director of Embedded Controls at Allison. “It will adjust based on loads and grade to deliver maximum performance. It will respond differently when the vehicle is fully loaded versus pulling an empty trailer.”

He also noted that vehicle manufacturers and owners could select the settings that balance performance and fuel economy. Options in the FuelSense 2.0 family, which comprises three versions, include improved Neutral at Stop, which reduces or eliminates the load on the engine when the vehicle is stopped. Another option, Acceleration Rate Management, mitigates aggressive driving by automatically controlling engine torque.

Cummins Inc. is also focusing on fuel savings. The engine maker has updated its B6.7 line, which produces from 200 to 325 hp (149 to 242 kW). Cummins also added start-stop capability, which is provided via software revisions. The upgrade brings solid improvements.

“It improves fuel efficiency by 8.5% on average; it can go as high as 13%,” said Jeff Caldwell, Executive Director for North American Truck OEMs at Cummins. “It also adds 5% in performance ratings. Stop-start adds 7% on top of the other benefits. The improvements reduce consumables and improve reliability. They also reduce noise and vibration.”

Daimler Trucks North America highlighted a different type of software offered on the Detroit DD8, which has a power range of 260-350 hp (194-261 kW) and a torque range of 660-1050 lb·ft (895-1424 N·m). Vehicles equipped with the 7.7-L in-line 6-cylinder engine will have access to the Detroit Connect Virtual Technician remote diagnostic service.

The telematic link lets technicians monitor a broad range of parameters to ensure services are performed only when needed. Virtual Technician also tells technicians which components have failed so they can prepare parts and equipment while the vehicle is being brought to the shop.

In another recent move, Isuzu Commercial Truck of America increased the B10 durability rating of its 5.2-L 4HK1-TC four-cylinder diesel engine to 375,000 mi (603,500 km). The B10 life rating means 90% of 4HK1-TC engines should last 375,000 miles before requiring major repairs. That’s an increase over the original prediction of 310,000 mi (498,900 km).