US EPA Tier 4 Final certified mobile generator sets with 150 kW to 275 kW power outputs are now available from Cummins Power Generation for the rental market. Cummins officials said the company conducted extensive field research to develop a reliable product to meet the latest emissions regulations. The mobile generators have been validated and are now available to rental operators and customers.

The new units are based on the Cummins QSB7 and QSL9 engine platforms that have undergone extensive refinements to meet the EPA Tier 4 Final regulations. Cummins was able to meet the new Tier 4 Final regulations through a combination of in-cylinder engine improvements, exhaust gas recirculation (EGR), selective catalytic reduction (SCR) exhaust aftertreatment, and diesel oxidation catalyst (DOC).  Due to the success of the in-cylinder combustion improvements, these engines do not require the use of a diesel particulate filter (DPF) to meet the new air quality standards. The simpler SCR-only solution helps reduce maintenance overhead and service costs.

In addition, the company claims that these mobile rental generators are approximately 4% to 5% more fuel efficient than previous Tier 3 models and deliver higher availability and longer running times between service intervals with no increase in overall package size. The Tier 4 Final regulations limit mobile generator set emissions to 0.4 grams per kWh of nitrogen oxides (NOx) and 0.02 grams per kWh of particulate matter (PM or soot). These levels represent a 90% reduction of the two pollutants from the previous Tier 3, which was introduced in 2005.
 
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