Detailed Characterization of Particle Emissions from Advanced Internal Combustion Engines

Detailed characterization of particle emissions from three different engine technologies were performed, two of which were advanced technology engines. One of the engines was a nonroad Tier 4 Final emission regulation compliant 6.8L John Deere PSS 6068 diesel engine operated with its production calibration strategy. The other two engine platforms were advanced engine technologies whose controllers were developed by Southwest Research Institute (SwRI). These included a dual fuel Navistar MaxxForce 13L natural gas-diesel engine and a Cummins ISX 15L diesel engine. The dual fuel engine was operated in two distinct modes, conventional dual fuel (CDF) mode and low temperature reactivity controlled compression ignition (RCCI) mode. The Cummins ISX engine was operated using a “hot” or low EGR combustion strategy. For each engine technology, the test campaign involved steady-state test modes ranging from low speed low load to high speed high load conditions. Regulated particulate matter (PM) mass, real-time soot mass, solid and total (solid + volatile species) particle number/size and elemental carbon/organic carbon mass were examined for all three engines. The CDF and RCCI applications exhibited high total PN emissions especially in the sub 23 nm size range. In the case of the dual fuel engine platform, solid particle emissions observed for the RCCI decreased between 18 % - 67 % relative to CDF mode. The “hot” combustion engine technology typically exhibited low PM/PN emissions for most operating conditions. Results from this program highlight that some advanced engine technologies have potential in reducing regulated particle emissions. However, they could be a source of unregulated particle emissions, especially in the sub 23 nm size range. Gaining such in-depth knowledge of their emission characteristics is important to develop aftertreatment solutions, and to understand their potential impacts on the environment.