Cummins announces 4-cylinder QSB3.3 and QSB4.5 engines will meet EPA Tier 4 Interim off-highway emissions in 2012. These engines range from 75-hp to 160-hp.
The lower emissions are achieved by using cooled Exhaust Gas Recirculation (EGR) for NOx control and exhaust aftertreatment for removing particulate matter. The 4-cylinder models were built with a more compact and simplified version of the Tier 4 Interim technology for the 6-cylinder QSB6.7 engine.
The High Pressure Common Rail (HPCR) fuel system employed on the Tier 3 QSB3.3 and QSB4.5 is already capable for Tier 4 Interim and will require no major change. An upgraded turbocharger with electronic control will be utilized to manage EGR flow across the entire engine rpm range. These engines retain the same 3.3- and 4.5-liter platforms and will be supplied as a fully integrated air-intake-to-exhaust system.
The particulate aftertreatment unit designed by Cummins for the Tier 4 Interim QSB3.3 and QSB4.5 removes more than 90% of particulate matter. The unit replaces the muffler in the exhaust stream and offers equivalent noise reduction, and it can be installed vertically or horizontally.
For more Information: Cummins