Search Results

SCR-on-filter, or SCRoF, is an emerging technology for different market segments and vehicle applications. The technology enables simultaneous particulate matter trapping and NOX reduction, and provides thermal management and aftertreatment packaging benefits. However, there is little information detailing the lubricant derived exposure effects on functional SCR performance. A study was conducted to evaluate the impact of various oil consumption pathways on a light duty DOC and SCRoF aftertreatment system. This aftertreatment system was aged utilizing an engine test bench modified to enable increased oil consumption rates via three unique oil consumption pathways. The components were characterized for functional SCR performance, ash morphology, and ash deposition characteristics. This included utilizing techniques, such as SEM / EDS, to evaluate the ash structures and quantify the ash elemental composition.

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.

With the advancement of engine technologies and combustion strategies, aftertreatment architectures are expected to evolve as they continue to be the primary emissions mitigation hardware. Some of the engine approaches offer unique challenges and benefits that are not well understood beyond criteria pollutant emissions. As such, there continues to be a need to quantify engine emissions characteristics in pursuit of catalyst technology development and the use of advanced simulation tools. The following study discusses results from an extensive engine emissions assessment for current state-of-the-art technology and novel combustion regimes. The engines tested include a Tier 4 final compliant 6.8 L John Deere PSS 6068 diesel engine, a modified 15 L diesel engine, and a dual fuel 13 L natural gas-diesel engine. The dual fuel engine could operate in conventional positive ignition mode (CDF) or low temperature reactivity-controlled compression ignition mode (RCCI).

This paper describes a new method for measuring oil consumption using laser induced breakdown spectroscopy (LIBS). LIBS focuses a high energy laser pulse on a sample to form a transient plasma. As the plasma cools, each element produces atomic emission lines which can be used to identify and quantify the elements present in the original sample. In this work, a LIBS system was used on simulated engine exhaust with a focus on quantifying the inorganic components (termed ash) of the particulate emissions. Because some of the metallic elements in the ash almost exclusively result from lube oil consumption, their concentrations can also be correlated to an oil consumption rate. Initial testing was performed using SwRI’s Exhaust Composition Transient Operation Laboratory®(ECTO-Lab®) burner system so that oil consumption and ash mass could be precisely controlled.

A push for more stringent emissions regulations has resulted in larger, increasingly complex aftertreatment solutions. In particular, oxides of nitrogen (NOX) and particulate matter (PM) have been controlled using two separate systems, selective catalytic reduction (SCR) and the catalyze diesel particulate filter (CDPF), or the functionality has been combined into a single device producing the SCR on filter (SCRoF). The SCRoF forgoes beneficial NO2 production present in the CDPF to avoid NH3 oxidation which occurs when using platinum group metals (PGM) for oxidation. In this study, mixed-metal oxides are shown to oxidize NO to NO2 without appreciable NH3 oxidation. This selectivity leads to enhanced performance when combined with a typical Cu-zeolite catalyst.

The most recent 2010 emissions standards for heavy-duty engines have established a tailpipe limit of oxides of nitrogen (NOX) emissions of 0.20 g/bhp-hr. However, it is projected that even when the entire on-road fleet of heavy-duty vehicles operating in California is compliant with 2010 emission standards, the National Ambient Air Quality Standards (NAAQS) requirement for ambient particulate matter and Ozone will not be achieved without further reduction in NOX emissions. The California Air Resources Board (CARB) funded a research program to explore the feasibility of achieving 0.02 g/bhp-hr NOX emissions.

Recent 2010 emissions standards for heavy-duty engines have established a limit of oxides of nitrogen (NOX) emissions of 0.20 g/bhp-hr. However, CARB has projected that even when the entire on-road fleet of heavy-duty vehicles operating in California is compliant with 2010 emission standards, the National Ambient Air Quality Standards (NAAQS) requirement for ambient particulate matter and Ozone will not be achieved without further reduction in NOX emissions. The California Air Resources Board (ARB) funded a research program to explore the feasibility of achieving 0.02 g/bhp-hr NOX emissions. This paper details engine and aftertreatment NOX management requirements and model based control considerations for achieving Ultra-Low NOX (ULN) levels with a heavy-duty diesel engine. Data are presented for several Advanced Technology aftertreatment solutions and the integration of these solutions with the engine calibration.

The 2010 emissions standards for heavy-duty engines have established a limit of oxides of nitrogen (NOX) emissions of 0.20 g/bhp-hr. However, the California Air Resource Board (ARB) projects that even when the entire on-road fleet of heavy-duty vehicles operating in California is compliant with 2010 emission standards, the National Ambient Air Quality Standards (NAAQS) requirement for ambient particulate matter (PM) and Ozone will not be achieved without further reduction in NOX emissions. The California Air Resources Board (CARB) funded a research program to explore the feasibility of achieving 0.02 g/bhp-hr NOX emissions.