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After-treatment systems (ATS) consisting of new catalyst technologies and particulate filters will be necessary to meet increasingly stringent global regulations limiting particulate matter (PM) and NOx emissions from heavy duty and light duty diesel vehicles. Fuels and lubes contain elements such as sulfur, phosphorus and ash-forming metals that can adversely impact the efficiency and durability of these systems. Investigations of the impact of lubricant formulation on the transfer of ash-forming elements to diesel particulate filters (DPF) and transfer of sulfur to NOx storage catalysts were conducted using passenger car diesel engine technology. It was observed that for ATS configurations with catalyst(s) upstream of the DPF, transfer of ash-forming elements to the DPF was significantly lower than expected on the basis of oil consumption and lube composition. Sulfur transfer strongly correlated with oil consumption and lubricant sulfur content.

A test program has been conducted to evaluate the low-temperature cranking, pumping and starting characteristics of light and heavy duty diesel trucks using various lubricants. The low-temperature performance of oils with different SAE viscosity grades and base stock type were evaluated. Included are formulations based on conventional mineral, hydrocracked and synthetic base stocks. The results show that lower viscosity grade oils using special base stocks, in particular synthetics, demonstrate improved low-temperature cranking and pumping performance over conventional lubricants. The engine test results are compared against laboratory low-temperature flow, cranking and pumpability tests.

Methanol continues to be an important alternative fuel candidate for use in spark ignition engines. In addition to its potential as an alternative energy source, methanol has been claimed to provide benefits in possibly reducing reactive hydrocarbon emissions which contribute to ozone formation. This has resulted in considerable interest in using methanol fuels in several U.S. urban areas to assist in air pollution reduction. As a result of government incentives on these issues, engine builders are now developing new generations of vehicles capable of operating on methanol. Lubrication of these engines will require methanol-compatible oil formulations. Test work has shown that some current quality engine oils, designed for use with gasoline fuel, severely limit engine durability due to excessive wear of the valve train, cylinder bore, and bearings. A laboratory engine test program using a 2.3-liter engine has been conducted to evaluate methanol-fueled engine lubrication.

Since the early 1970's, the dominant trend in aircraft gas turbine engines has been increasing fuel efficiency. This has resulted in higher operating temperatures which, along with other engine design changes, place additional stress on the lubricant. This paper describes the laboratory evaluation of an oil developed to meet those more demanding conditions and presents field performance evidence in support of expectations based on laboratory tests.