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This study, lead by Elf AQUITAINE for several years, shows the possibility to use ETBE instead of MTBE as a gasoline component and compares properties of these two ethers regarding different parameters like octanes, volatility, engine cleanliness, stability of the ethers themselves and of gasoline blends, lubricant compatibility and toxicological data. ETBE appears at least as good as MTBE and sometimes better, as ETBE is chemically more similar to hydrocarbons than MTBE and can be used avantageously as a gasoline oxygenated component.

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.

For environmental and economical reasons, reduction of fuel consumption is becoming a major concern for car and truck manufacturers and customers. Analysis of consumer way of using their cars indicates, that it is by working on low temperature and low engine rotating speed that benefits given by the lubricant can be optimized. Analysis of customers way of using their trucks indicates that the engine is mainly working at stabilized temperature, in hydrodynamic conditions; in such conditions (for exemple highway), the reduction of fuel consumption coming from the engine lubricant is rather low, compared with passenger car applications. On that basis, specific rig tests have been developed to help the lubricant formulator. Each of these tests is specifically designed, for different engine friction area study: valve train, rings/liner, crankshaft bearings. The correlation between engine friction on each area and fuel consumption reduction is discussed.

This communication examines three strategies of predictive lubricant monitoring and replacement, used for farm tractors or similar vehicles. These strategies optimise the draining periodicity. They are the off-line follow-up, the sensors follow-up and the analytical model follow-up. The implementation of the suggested analytical model will be discussed, on the basis of field collected data (on a series of tractors, either customer's or on loan). Regular oil samples, and significant ones carried out at the end of the study, were taken and analysed in order to predict the evolution of the lubricant characteristics. Extensions to the experimental study were carried out at the end of this work. They are discussed in the paper (FZG gear scuffing, 4 ball wear and EP…).