
Heavy-duty diesel engine maker Cummins this weekend pulled the curtain back on two new 15-liter engine offerings that will come to market late this year. The 2017 Cummins X15 engines offer two new configurations: The fuel-economy focused X15 Efficiency spec for long-haul applications and the X15 Performance spec for heavy-haul and other more demanding applications.
Cummins says both engines exceed 2017 Environmental Protection Agency emissions standards that take effect next year.

The engine maker also unveiled a leaner X12, which will come to market in 2018. The company also announced a rebranding of its heavy-duty engines, dropping the “ISX” branding in favor of the new “X” nomenclature.
While the ISX platform has only one 15-liter starting option, the X series offers two: The fuel-sipping X15 Efficiency Series geared toward line-haul and regional markets, and the X15 Performance Series, built specifically for heavy-haul, vocational and other demanding applications.
Cummins made several hardware changes to improve performance on the X15 Performance engine, including a high-flow EGR cooler and piston cooling nozzles and exhaust valves to improve reliability. The X15 Performance Series boasts from 485 to 605 horsepower, torque ratings from up to 2,050 lb-ft, and as much as 600 braking horsepower.
The X15 Efficiency Series ranges from 400 to 500 horsepower and 1,450 to 1,850 lb-ft of torque, and 400 braking horsepower at 1,300 rpm. In addition, Cummins has added predictive cruise control to its ADEPT suite of connected vehicle technology.