Douglas M. Yost

Feasibility of Using Full Synthetic Low Viscosity Engine Oil at High Ambient Temperatures in Military Vehicles

Abstract : Advancements in lubricant technology over the last two decades, in particular, the availability of high quality synthetic base oils, has set the stage for the development of a new fuel efficient, multifunctional powertrain lubricant with extended drain capabilities. Given its large fleet size, diversity of equipment, and range of environments in which it must operate, the U.S. Army is perhaps uniquely positioned to benefit from these advancements. This report summarizes the initial work that the U.S. Armys Fuel and Lubricants Technology Team has been doing to establish the technical feasibility of developing a new multifunctional, fuel efficient powertrain lubricant for the Armys fleet of combat and tactical vehicles and equipment referred to as the Single Common Powertrain Lubricant (SCPL) project. The feasibility of using a low viscosity diesel engine oil in Army engines was determined. At desert like operating conditions, a prototype SCPL provided similar overall performance as an SAE15W.40 oil in 3 Army engines.

Emissions of Toxicologically Relevant Compounds Using Dibutyl Maleate and Tripropylene Glycol Monomethyl Ether Diesel Fuel Additives to Lower NOx Emissions

A previous paper reported (SAE Paper 2002-01-2884) that it was possible to decrease mode-weighted NOx emissions compared to the OEM calibration with corresponding increases in particulate matter (PM) emissions. These PM emission increases were partially overcome with the use of oxygenated diesel fuel additives. We wanted to know if compounds of toxicological concern were emitted more or less using oxygenated diesel fuel additives that were used in conjunction with a modified engine operating strategy to lower engine-out NOx emissions. Emissions of toxicologically relevant compounds from fuels containing triproplyene glycol monomethyl ether and dibutyl maleate were the same or lower compared to a low sulfur fuel (15 ppm sulfur) even under engine operating conditions designed to lower engine-out NOx emissions. The emissions of toxicologically relevant compounds using a 100% Fisher Tropsch fuel, a recognized clean fuel, were equivalent to or less than emissions from the two oxygenated diesel fuels. These results suggest that these oxygenated diesel fuel additives can be used to lower engine-out NOx emissions without risking any increase in tailpipe emissions of compounds of toxicological concern.

Engine wear with methanol fuel in a nitrogen-free environment

Several test programs have shown that the combustion of methanol in spark ignition engines can cause unusually high corrosive wear of the upper cylinder bore and ring areas. In this study, a 2.3-liter engine fueled with methanol was operated in a nitrogen-free atmosphere to determine the importance of nitric acid in the corrosion mechanism. A 20-hour steady-state test was carried out using neat methanol as the fuel and a mixture of oxygen, argon, and carbon dioxide in place of air. The intake and exhaust gases were frequently analyzed to be sure their compositions were constant and free of nitrogen. Emission measurements showed only trace amounts (1 ppm) of NOx in the exhaust. Analysis of the condensates from the exhaust and blow also showed that the wear indicated by iron buildup in the lubricant was essentially the same in the nitrogen-free test as that detected in baseline engine tests combusting methanol-air mixtures. It was concluded that nitric acid does not play a role in the corrosion of the upper cylinder bore and ring areas of methanol-fuelded engines.

Emissions of toxicologically relevant compounds using fischer-tropsch diesel fuel and aftertreatment at a low NOx, low power engine condition

Previously we reported (SAE Paper 2005-01-0475) that emissions of toxicologically relevant compounds from an engine operating at low NOx conditions using Fischer-Tropsch fuel (FT100) were lower than those emissions from the engine using an ultra-low sulfur (15 PPM sulfur) diesel fuel (BP15). Those tests were performed at two operating modes: Mode 6 (4.2 bar BMEP, 2300 RPM) and Mode 11 (2.62 bar BMEP, 1500 RPM). We wanted to evaluate the effect on emissions of operating the engine at low power (near idle) in conjunction with the low NOx strategy. Specifically, we report on emissions of total hydrocarbon (HC), carbon monoxide (CO), NOx, particulates (PM), formaldehyde, acetaldehyde, benzene, 1,3-butadiene, gas phase polyaromatic hydrocarbons (PAHs) and particle phase PAHs from a DaimlerChrysler OM611 CIDI engine using a low NOx engine operating strategy at Mode 22 (1.0 bar BMEP and 1500 RPM). Mode 22 did produce some differences in emissions levels and aftertreatment performance for toxicologically relevant species compared to Modes 6 and 11. Further, uncontrolled step changes in these emissions were observed to occur at the low exhaust temperature of Mode 22. Nevertheless the emissions for Mode 22 with Fischer-Tropsch diesel fuel were generally consistent with Modes 6 and 11.

The measurement of octane numbers for methanol and reference fuels blends

The purpose of this work was to develop a series of octane reference fuels for road testing methanol fueled vehicles. Preliminary attempts to measure the research octane number of neat methanol by the standard ASTM test procedure produced anomalous results. This led to a more basic method of measuring the octane number based on the incipient knock compression ratio