Cummins Inc. claimed in a Sept. 21 announcement that it had achieved an industry milestone by commencing production and supply of the first EPA Tier 4 Interim and EU Stage IIIB certified engines and aftertreatment for early installation by off-highway equipment customers. The latest-generation QSB6.7 and QSL9 engines, certified with integrated Cummins Particulate Filter exhaust aftertreatment, are built at the Cummins Rocky Mount plant in North Carolina for customers in North America and East Asia, with the Darlington plant in the U.K. supplying European customers. Before finalization of the engine build specification for production release, the QSB6.7 and QSL9 underwent a series of field tests on commercial operations to validate performance and in-service reliability; the engines achieved up to 5% improved fuel efficiency and faster engine response, boosting machine productivity, according to Cummins. The new emissions regulations take effect Jan.1 for engines over 173 hp (129 kW). The QSB6.7 engine is certified to 300 hp (224 kW) and the QSL9 up to 400 hp (298 kW). The engine supplier says that technology already successfully used with its EPA 2007 on-highway engines helped to accelerate its Tier 4 Interim program.