Even though Tier 4 Final regulations are not here yet, Cummins is not wasting anytime in telling its hundreds of engine customers what the company will do for emissions reductions in the QSL9 and QSX15 engines.
The 9-liter mill combines a Cummins Compact Catalyst with SCR to meet the near zero emissions levels. The CCC is positioned in front of the SCR system for easier and more flexible installation options, and the two elements can be configured in a horizontal, vertical or switchback configuration. Cummins characterizes the CCC as a “fit and forget” component, meaning it will not need periodic ash cleanout maintenance.
With the exception of the SCR system the Tier 4 Final version of the QSL9 uses most of the same architecture as the Tier 4 Interim version, including variable geometry turbocharger, Xtra high pressure injection (XPI fuel injection) and space saving direct flow air cleaner technology.
The QSX15 engine uses a Cummins Particulate Filter with an SCR system, a design it will share with the QSX11.9. Power ratings get a boost on the bigger engine (up to 675 hp) and power density rises to 45 hp per liter on the QSX15 and 44 hp per liter on the QSX11.9. Both engines gained about 5 percent fuel efficient moving from Tier 3 to Tier 4 Interim and the company claims additional fuel gains of 3 to 4 percent when the Tier 4 Final versions hit the streets in 2014.