Search Results

Current specifications for automatic-transmission fluids and gear oils have viscosity limits which are determined by ASTM D 2983. However, that test is plagued by poor precision. This paper describes the development of a method using the Mini-Rotary Viscometer to make the determination of apparent viscosity at the same nominal shear stress as ASTM D 2983. In this test procedure, samples are cooled in a manner similar to that described in ASTM D 2983. Experimental data were obtained on a mixture of 17 automatic-transmission and gear-oil fluids that included a number of different formulation strategies and commercial products. The results of this method yield a nearly one to one correlation with the results determined by ASTM D 2983.

Thermal barrier coatings have been shown to be effective at reducing particulate emissions from diesel engines. Prior work by the authors has demonstrated a significant decrease in particulate emissions from a thermal barrier coated, single-cylinder, indirect injection (IDI) diesel engine, primarily through reduction of the volatile (VOF) and soluble (SOF) fraction of the particulate. Most of this prior work relied on conventional, commercially available, petroleum-based lubricants. Recently, the authors demonstrated additional particulate emissions reductions when a high oleic sunflower-based lubricant was used instead of a conventional petroleum-based lubricant. This paper concerns the manner in which the particulate was reduced, and reports on the changes in particulate composition and morphology between the two lubricants. Composition was examined quantitatively through thermal analysis of the particulate from a single-cylinder IDI diesel engine.

Legislation world-wide has made it necessary to find ways to control the level of engine emissions and reduce the damage to our environment. Increasing restrictions have made the elimination of zinc dithiophosphates from crankcase oils and increasing the effectiveness of catalytic converters viable options. Lead and phosphorus containing compounds in the exhaust are known catalyst poisons that shorten the life of current automotive catalysts. Unleaded fuel has successfully resulted in a reduction of harmful emissions due to the fuel. Current government and industry research is actively pursuing replacement of phosphorus additives with phosphorus free additives. Several phosphorus-free oils were developed and are evaluated in bench tests in this study. Test comparisons with phosphorus- containing oils demonstrated satisfactory oxidation stability and wear performance of the phosphorus free oils.

Thermal barrier coated diesel engines, also known as low heat rejection (LHR) engines, have offered the promise of reducing heat rejection to the engine coolant and thereby increasing overall thermal efficiency. However, the larger market potential for thermal barrier coated engines may be in retrofitting in-service diesel engines to reduce particulate emissions. Prior work by the authors has demonstrated a significant decrease in particulate emissions from a thermal barrier coated, single-cylinder, indirect injection (IDI) diesel engine, primarily through reduction of the volatile (VOF) and soluble (SOF) fraction of the particulate. This prior work relied on conventional, commercially available, petroleum-based lubricants. The present study concerns the additional benefits for particulate reduction provided by vegetable oil lubricants. These lubricants are derived from renewable resource materials and can provide a reduction in lubricant generated particulate matter.

Reports published by Gulf R&D Co. and Battelle Columbus Laboratories under contract to the Coordinating Research Council's APRAC project group CAPE-24 were reviewed. Both studies failed to verify the accuracy of polynuclear aromatic hydrocarbon (PNA) emission measurements from heavy-duty diesel engines. Thermal decomposition and chemical reactions of the PNA occur in raw exhaust at temperatures above 500°F. Therefore, pipes which transfer exhaust to dilution tunnels can significantly reduce the apparent emission values. Dilution tunnel conditions have comparatively little effect on PNA measurements. However, vapor traps are required behind particle filters to assure complete collection of 4-ring PNA compounds. Guidelines are presented for controlling and testing sampling systems for accurate PNA emission measurements.