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Reports of disabling diesel engine seal failures which accompanied the introduction of low sulfur diesel fuel in October '93 prompted an in-depth survey of diesel fuel chemical and physical properties. The purpose of the survey was to anticipate other possible problems which might arise with the newly introduced low sulfur fuels. The survey will produce a database containing over 1000 number 2 diesel fuels from various parts of the US. About 75% of the samples tested were on-highway low sulfur diesel fuels. Samples analyzed were from the D-A Lubricant Company, Cummins customers failures (truck fleets of various sizes), and a number of retail fueling stations. Properties under investigation are % Sulfur, Cloud/Pour Points, Viscosity, API Gravity, TAN/TBN, Boiling Range, Aromatics content, Heat Content, Lubricity, and Peroxide number.

The specific goal of this project was to determine if there is a difference in the lube oil degradation rates in a heavy-duty diesel engine equipped with an EGR system, as compared to the same configuration of the engine, but minus the EGR system. A secondary goal was to develop FTIR analysis of used lube oil as a sensitive technique for rapid evaluation of the degradation properties of lubricants. The test engine selected for this work was a Caterpillar 3176 engine. Two engine configurations were used, a standard 1994 design and a 1994 configuration with EGR designed to meet the 2004 emissions standards. The most significant changes in the lubricant occurred during the first 50-100 hours of operation. The results clearly demonstrated that the use of EGR has a significant impact on the degradation of the engine lubricant.

Corrosive wear of non-ferrous engine components by lubricants is a concern of all major heavy duty diesel engine manufacturers since warranty on key engine components has been extended to 500,000 miles. Several commercial lubricants have been linked to premature cam and rod bearing failures induced by corrosion in certain fleets. Although the overall failure rate is low, specific fleets have experienced significantly higher failure rates due to the lubricants used. These failures usually occur at high mileages but less than 500,000 miles. This kind of slow corrosion easily escapes detection of engine tests contained in current oil specifications, and it represents a serious issue in long term warranty cost to diesel engine manufacturers. A comprehensive fleet database has been established to identify the most corrosive lubricants. These lubricants have served as reference oils to develop a corrosion bench test.