Cummins introduces four new EPA Tier-4 Interim and EU Stage IIIB emissions-meeting engines. The next generation of 4-cylinder QSB3.3 and QSB4.5 engines are designed for compact equipment. The QSX11.9 and QSX15 engines range from 300 hp to 600 hp. The XPI system is complemented by a single Cummins turbocharger able to continuously vary airflow boost to match engine rpm and load demands. The units feature a scaled-down cooled Exhaust Gas Recirculation system and Cummins particulate exhaust aftertreatment. The direct-flow air cleaner reduces space claim by up to 35 percent compared with typical Tier-3 filters.