While diesel engine development activity has been focused for many years on meeting emissions standards, there is little doubt that engine electronics have also continued to evolve. Today, the advanced capabilities designed into modern diesels are helping fleets achieve efficiency objectives and boost fuel economy. Cummins ISX engines, for example, are enabled with SmartTorque ratings. These engine calibrations deliver up to 200 lb.-ft. of extra torque in the top gears, making it possible to run longer in gears where fleets can reap the greatest fuel economy benefit. Detroit Diesel Corp's newest engines incorporate an amplified common rail system that optimizes each injection event to minimize fuel consumption. Many factors, from vehicle design and specifications to driver competence, can impact fuel efficiency in today's over-the-road trucks. For their part, engine manufacturers are also enabling advanced electronics to help achieve the goal of improving fuel economy and cutting costs.