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A 1000-hour test was conducted to determine the durability effects of 2-ethylhexyl nitrate (2-EHN) cetane improver on heavy duty diesel engines. Two identical 1993 DDC Series 60 engines were run side-by-side on a severe duty cycle. Both were fueled with a commercial low sulfur fuel. The fuel in one engine was treated with 7500 ppm of 2-EHN cetane improver. At the end of the test, engine wear and deposit comparisons were made to determine the effect of high cetane improver treat rates on engine durability. After 1000 hours of operation, the engine running on fuel treated with 2-EHN cetane improver exhibited lower engine wear and deposits than the engine run without cetane improver. Analysis of oil samples drawn every 100 hours indicated no difference in wear metals or other physical properties when cetane improver was used. Fuel analyses demonstrated that 2-EHN did not degrade under the high operating temperatures of this modern heavy-duty diesel engine.

A laboratory Ball Rust Test (BRT) has been jointly developed by General Motors and Ethyl Corporation to replace the current Sequence IID engine test, and standard test procedures have been established to assess the rust/corrosion protection ability of experimental and commercial oils. Under the optimum test conditions developed, BRT data on eight industry reference and eighteen industry supplied oils showed a reasonable correlation with Sequence IID average rust test results. The capability of the BRT for differentiating oil quality was further demonstrated by evaluating 132 commercial oils obtained from around the world: oils with insufficient protection, such as those with API performance ratings of SA to SE, performed poorly in the BRT; oils with API ratings of SF, SG, and SH performed well in the test. The BRT will be made available to ASTM for development of a precision statement and for inclusion in future engine oil performance specifications.

This paper traces the evolution of the ASTM Test Monitoring Center (TMC) from its modest beginnings in 1976 to the present. Formed as an unbiased and non-aligned group within ASTM Subcommittee D02.B, the TMC operates a reference oil based calibration system that serves both the producers and users of automotive lubricants. Governed by the ASTM Test Monitoring Board, the center's primary mission is to calibrate engine dynamometer test stands used to conduct various ASTM test methods for evaluating lubricant performance. The core services of the TMC have remained the same over its nearly 25 year history. The center stores and distributes ASTM reference oils and is responsible for assuring, through the use of analytical testing, the quality and consistency of the oils. The number of reference oils handled by the TMC has steadily increased over time such that today the center inventories some 100 different formulations having a total volume of 65,000 gallons.

The Ball Rust Test (BRT), a corrosion bench test developed for evaluating the rust preventing qualities of crankcase motor oils, is being proposed as a replacement for the ASTM Sequence IID engine test. Details of this bench test are described in the paper “Development of the Ball Rust Test - A Bench Test Replacement for the Sequence IID Engine Test.” In this paper, a good correlation was established between rust performance in the BRT versus the IID engine test rust rating for a variety of oils. Following the development of the BRT, a comprehensive study was conducted using this bench test to define the effectiveness of oil additive type and concentration on rust inhibition. This paper summarizes these results and offers insight into effective rust control in a corrosive environment. High-base metallic sulfonates were found to be most effective at preventing rust primarily due to preservation of alkalinity.

The oxidation of surrogate diesel fuels composed of mixtures of three pure hydrocarbons with and without their cetane numbers chemically enhanced using 2-ethylhexyl nitrate (2-EHN) is studied in a variable pressure flow reactor over a temperature range 500 - 900 K, at 12.5 atmospheres and a fixed reaction time of 1.8 sec. Changes in both low temperature, intermediate temperature, and hot ignition chemical kinetic behavior are noted with changes in the fuel cetane number. Differences appear in the product distribution and in heat release generated in the low and intermediate temperature regimes as cetane number is increased. A chemically enhanced cetane fuel shows nearly identical oxidation characteristics to those obtained using pure fuel blends to produce the enhanced cetane value. The decomposition chemistry of 2-EHN was also studied. Pyrolysis data of 10% 2-EHN in n-heptane and toluene are reported.