Elizabeth A. Schiferl

Efficiency in Research, Development and Production: The Statistical Design and Analysis of Chemical Experiments

Economy and efficiency in research and development essentials of statistical analysis some important concepts in design and analysis range-finding experiments factorial design at two levels fractional factorial designs at two levels fractional factorial designs in sequence consistency of processes and products the optimization of processes and products factorial experiments at three levels sequential operation, composite designs and response surface methodology Taguchi methodology.

The Impact of Lubricant and Fuel Derived Sulfur Species on Efficiency and Durability of Diesel NOx Adsorbers

Global emission legislations for diesel engines are becoming increasingly stringent. While the exhaust gas composition requirements for prior iterations of emission legislation could be met with improvements in the engines combustion process, the next issue of European, North American and Japanese emission limits greater than 2005 will require more rigorous measures, mainly employment of exhaust gas aftertreatment systems. As a result, many American diesel OEMs are considering NOx adsorbers as a means to achieve 2007+ emission standards. Since the efficacy of a NOx adsorber over its lifetime is significantly affected by \sulfur (sulfur poisoning), forthcoming reductions in diesel fuel sulfur (down to 15 ppm), have raised industry concerns regarding compatibility and possible poisoning effects of sulfur from the lubricant. Since relatively little is known about the interaction between lubricant derived sulfur and NOx adsorbers, a joint technical program was conducted using a Cummins 5.9L engine and NOx adsorbers supplied by Delphi. Fuel sulfur was kept constant (2ppm) while the effects of high (0.6%) and ultra low (0.003%) S containing lubricants were examined. Statistical analysis of the change in NOx conversion revealed that the loss in NOx conversion was proportional to and mainly dependent on the rate of total sulfur exposure, regardless of the sulfur source. In addition, the results of this study allow review of the effects of engine oil sulfur in perspective to the future EPA mandated ultra low sulfur diesel fuel. It should be noted that this work describes only initial sulfur poisoning studies and that no evaluations of NOx adsorber desulfations are addressed.

Gear Oil Viscosity Modifiers and Their Impact on Efficiency

The essential functions of an automotive gear lubricant viscosity modifier (VM) are to maintain fluid film protection of gears and bearings as the lubricant warms to operating temperature, to improve cold temperature flow for efficient lubrication in winter and to minimise viscosity loss in a high shear, high load environment. Although a number of different VM technologies can be considered appropriately resistant to permanent shear for automotive gear oils use, their effect on fluid efficiency can vary widely. This paper outlines the study of a series of different VM technologies assessing relationship of operating temperature, operating viscosity and axle efficiency under different load and speed regimes. The fluids presented were formulated to equal kinematic viscosity at 100 °C but vary widely in viscosity index (VI), elastohydrodynamic (EHD) traction and EHD film thickness. The differences observed during efficiency testing were qualitatively related to the rheological properties of the VM technology present and further related to the operating temperature and operating viscosity.