Tier 4 InterimEPA Tier 4 Interim regulations took effect in North America in January 2011 for engines above 173 hp (129 kW) and in January 2012 for engines at or below 173 hp (129 kW). Equivalent EU Stage IIIB regulations began at the same time for European Union countries, while similar regulations commenced in 2013 for Japan Ministry of Land, Infrastructure and Transportation (JMLIT) / Japan Ministry of the Environment (JMOE).
Cummins QSB6.7, QSL9. QSX11.9 and QSX15 engines met the 2011 low emissions standards using an integrated Cummins Particulate Filter exhaust aftertreatment and a cooled exhaust gas recirculation (EGR) system incorporated on the engine.
Cummins QSB6.7, QSB4.5, and QSB3.3 engines met the 2012 low emissions standards with an integrated Cummins Compact Catalyst exhaust aftertreatment and a cooled exhaust gas recirculation (EGR) system incorporated on the engine.
Cummins Tier 4 Interim products have performed extremely well with greater productivity and reliability across a wide range of machine types, duty cycles and environments. These include machines such as excavators, mud pumps, forestry feller bunchers, front-end loaders, snow groomers, compressors, heavy forklifts, yard spotter trucks/ terminal tractors, rock drills and four-wheel-drive tractors.