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Tier 4 Emission Reductions: Quick Facts and Comparison

Miguel Jimenez

Ever since Cummins Power Generation introduced the Tier 4i and Tier 4 final product line, much has been discussed about the remarkable emission reduction capability these packages have. Complex, state-of-the-art devices such as the Cummins Selective Catalytic Reduction (SCR) system, the Diesel Particulate Filter (DPF) and the aftertreatment control board have enabled us with the technology required to meet the very stringent, near-zero emissions EPA Tier 4 requirements. As part of this blog entry, I want to provide a different perspective as to what our engineers in Cummins Power Generation have accomplished, along with some trivial comparisons.

For this study,  I compared the emission reductions between our stationary emergency 2000 kWe, EPA Tier 2 model DQKAB, and our non-emergency 2000 kWe, EPA Tier 4 final DQKAL generator set. Comparing Total Particulate Matter (TPM) emissions at 75% load, our Tier 4 final capable product achieves a 99.5% reduction in PM emissions when compared to our Tier 2 product. To demonstrate how remarkable this reduction is, the particulates generated over one hour on a Tier 2 unit would be the equivalent of running a Tier 4 final unit for more than 8 days, continuously.

A very similar comparison can be made by selecting another criteria pollutant, oxides of nitrogen (better known as NOx). This time, we will benchmark the DQKAB emissions with the Tier 4 interim DQKAL product at full rated power, 2 MWe. As discussed in more detail on previous entries, fundamentally speaking, the SCR system converts NOx into nitrogen gas (N2) and water (H2O) through the use of diesel exhaust fluid, or DEF – a urea based solution. This, together with our latest control in emissions technology, enables CPG to achieve a NOx reduction greater than 91 percent, enough to reduce more than 30 pounds of NOx per hour of operation at full rated power.

It is hard to argue that the latest EPA regulations represented an unprecedented challenge in the stationary generator set industry. Nonetheless, by integrating our world-class expertise in internal combustion engines, emissions technologies and advanced controls, Cummins Power Generation has been capable of supplying a certified and compliant product ahead of the federal deadline, not by months, but years ahead. This is Tier 4 peace of mind.

For more information about our Tier 4i and Tier 4 final compliant and certified products, please contact your local Cummins distributor.