Daimler to Debut Predictive Powertrain Controller for Buses

Daimler AG says it can hike the average fuel economy of large buses more than 9% with its predictive powertrain control (PPC) system.

The company plans to debut the technology this summer in its top-of-the-line Setra TopClass 500 coach. By year-end it will expand the technology to the Mercedes-Benz Travego and Setra ComfortClass 500 buses.

PPC accesses topographical data available for virtually all main roadways in Europe and pairs it with GPS that accurately locates the coach and the elevation changes of the route ahead. The system also monitors the bus's current speed, specified speed, vehicle mass, engine load and transmission performance.

PPC then manages the powertrain to optimize fuel economy through a broad range of adjustment options.

The system automatically downshifts the transmission in anticipation of inclines and reduces power before cresting a hilltop. It allows the powertrain to freewheel on downhill gradients with light peak engine revs to maintain proper speed. When deemed useful, it also can shift the transmission into neutral to prolong freewheeling without engine drag losses.

Daimler recently gave two dozen European journalists who specialize in bus and coach reporting the chance to test various iterations of PPC-equipped Setra buses in Germany over five days and 4,000 km (2,500 miles). Without PPC, the buses averaged 7.4 mpg over hilly routes. With the technology, the average climbed to 8.2 mpg over the same roads.