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Results of engine bench tests on a 1998 heavy-duty diesel engine have confirmed the emissions reduction performance of a U.S. Environmental Protection Agency (EPA) registered platinum/cerium bimetallic fuel borne catalyst (FBC) used with several different catalyzed and uncatalyzed diesel particulate filters (DPF's). Performance was evaluated on both a 450ppm sulfur fuel (No.2 D) and a CARB 50ppm low sulfur diesel (LSD) fuel. Particulate emissions of less than 0.02g/bhp-hr were achieved on several combinations of FBC and uncatalyzed filters on 450ppm sulfur fuel while levels of 0.01g/bhp-hr were achieved for both catalyzed and uncatalyzed filters using the FBC with the low sulfur CARB fuel. Eight-mode steady state testing of one filter and FBC combination with engine timing changes produced a 20% nitrogen oxide (NOx) reduction with particulates (PM) maintained at 0.01g/bhp-hr and no increase in measured fuel consumption.

The Tank-Automotive RD&E Center periodically conducts foreign materiel evaluations to assess the current state of the art for ground vehicle technologies. The Propulsion Laboratory is conducting performance evaluations of an opposed-piston two-stroke diesel tank engine produced by the Kharkov Design Bureau in Ukraine. A key factor in the performance of all two-stroke engines is the scavenging process, which determines how well the cylinders are emptied of exhaust and filled with fresh air. The overall air flow rate is not sufficient to determine this, as a significant amount of air may be lost through the exhaust ports during the scavenging process. The inlet tracer gas method was employed to provide the additional data required. With methane as the tracer, it produced reasonable and consistent data over a wide range of engine speeds and loads. The inlet tracer gas method was found to be an effective tool for measuring the scavenging performance of a running two-stroke diesel engine.

This study compared diesel exhaust emission from four different diesel fuels: a conventional low sulfur D2 diesel (0.03% sulfur, 28% aromatics), California Air Resources Board (CARB) diesel (0.015% sulfur, 8% aromatics), “Swedish” diesel (<0.001% sulfur, 4% aromatics), and a Fischer-Tropsch (F-T) diesel (<0.0001% sulfur, <0.1% aromatics) fuel. The comparison included regulated emissions, hydrocarbon speciation, air toxics, aldehydes and ketones, particle size distribution, and greenhouse gas emissions. Testing was conducted using a Cummins B-Series engine installed both in a heavy light-duty truck operating on a chassis dynamometer and on an engine dynamometer. The chassis driving cycles included city, highway, and aggressive driving operation. Engine dynamometer tests included the U.S. transient cycle.

Semi-volatile organic compounds (SVOC) are a group of compounds in engine exhaust that either form during combustion or are part of the fuel and lubricating oil. Since these compounds occur at very low concentrations in diesel engine exhaust, the methods for sampling, handling, and analyzing these compounds are critical to obtaining good results. An improved dilute exhaust sampling method was used for sampling and analyzing SVOC in engine exhaust, and this method was performed during transient engine operation. A total of 22 different SVOC were measured using a 2012 medium-duty diesel engine. This engine was equipped with a stock diesel oxidation catalyst (DOC), a diesel particulate filter (DPF), and a selective catalytic reduction (SCR) catalyst in series. Exhaust concentrations for SVOC were compared both with and without exhaust aftertreatment. Concentrations for the engine-out SVOC were significantly higher than with the aftertreatment present.

Since the conception of the internal combustion engine, smoky and ill-smelling exhaust was prevalent. Over the last century, significant improvements have been made in improving combustion and in treating the exhaust to reduce these effects. One group of compounds typically found in exhaust, polycyclic aromatic hydrocarbons (PAH), usually occurs at very low concentrations in diesel engine exhaust. Some of these compounds are considered carcinogenic, and most are considered hazardous air pollutants (HAP). Many methods have been developed for sampling, handling, and analyzing PAH. For this study, an improved method for dilute exhaust sampling was selected for sampling the PAH in diesel engine exhaust. This sampling method was used during transient engine operation both with and without aftertreatment to show the effect of aftertreatment.