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The thermomechanical fatigue assessment in the automotive industry is discussed. The design strategy is based upon a consistent approach of the thermomechanical loading, the mechanical constitutive law of the material, the damage parameters and the fatigue strength criteria. The good understanding of these different steps allows to perform predictive calculations of automotive parts subjected to thermomechanical loading. The main hypotheses and modeling choices are presented and results are illustrated by a series of computations on real 3D structures. Cracked area and lifetime prediction are described in the case of aluminum alloy cylinder heads submitted to transient thermal loadings.

The fatigue design is realized at PSA within a probabilistic approach. This approach takes into account the industrial context of the design. It includes the analysis of customer distribution, the handling of the production scatter, and the definition of relevant loading specifications ad acceptance criterion for the designers. This approach permits to avoid variable amplitude analysis by the mean of an appropriate fatigue equivalence method, and by the mean of the Dang Van criterion for the fatigue analysis of the FEM results.

2-Methyltetrahydrofuran, MTHF, can be produced from waste cellulose at a cost as low as US$ 0.60 per gallon ($ 0.16 per liter). Prior work in Florida has indicated good driveability and fuel system compatibility at MTHF levels up to 100 vol.%. FTP exhaust emissions testing is reported here using fuel consisting of 60 vol.% MTHF and 40 vol.% gasoline, and a single vehicle equipped with adaptive-learn, port electronic fuel injection and a closed-loop, three-way catalyst. The emissions effect of the MTHF fuel compared to the gasoline base used to blend the fuel was to produce significant reductions in HCs (by 52%), CO (by 20%), ozone forming potential (by 39%), and benzene (by 75%). Increases in NOx(not significant at 13%), carbonyls (by 37%) and NMOG-specific ozone reactivity (33%) were also found. Hydrocarbon and carbonyl speciation results are also reported.

Factors contributing to clogging of fine porosity filters in automobile fuel systems were investigated in the laboratory. Analyses of deposits from filters of cars operated on commercial gasolines indicated that clogging could be caused by metal corrosion products, dirt, water, additives, and microorganisms. The effects of these substances on clogging were studied using filtration tests under various conditions. Fine sediment dispersed in fuels readily clogged filter elements. Certain surfactant additives in gasoline accelerated filter clogging by promoting suspension of corrosion products with free water present. Some gasoline additives reacted with certain contaminants to form a gelatinous material which caused very rapid filter clogging.