The pursuit of a dominating diesel engine

Engineers at Cummins and Detroit Diesel believe the diesel engine will assume a larger share of future light-truck sales.

Two manufacturers with solid reputations in the heavy-duty engine field are taking aim at the light-duty market. Light trucks, which include pickups, SUVs, and vans, comprise over 50% of family vehicles in the U.S. Automakers have repeatedly increased light-truck vehicle size in response to customer demand. These marketing characteristics coupled with relatively low fuel prices within the U.S. have drastically changed the product mix away from smaller, more fuel-efficient cars toward larger, more profitable light trucks. This trend has also resulted in decreasing fleet fuel economy average, making it difficult for automakers to reach CAFE targets.

Detroit Diesel Corp. (DDC) developed an engine specifically for the North American light-truck market, with the first engine firing just 228 days after pencil touched a clean sheet of paper. The process began with a quality function deployment (QFD) analysis, which prioritized the development criteria. QFD captures primary customer wants, and through an unbiased process, evaluates tradeoffs and dependencies. In the first QFD phase, these parameters are reduced to technical system expectations, which form the basis for the second QFD phase and, ultimately, the engine-design process. The development process integrated a colocated, fully cross-functional team among suppliers and DDC. The first demonstration vehicle was driven 12 weeks after the first engine fired.