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New environmental regulations require significant reduction of fuel consumption and engine emissions. This implies improvement of the internal combustion (I.C.) process, reduction of friction, development of complex after-treatment systems, and a reduction of oil consumption. New technical challenges are related to fuel dilution problems in diesel and super-ethanol engines; new wear problems are due to fuel dilution and soot loading in the lubricant; clogging and poisoning problems of after-treatment systems are related to oil consumption, etc. Therefore, researchers and engineers need appropriate tools to better understand and solve these new problems. The paper focuses on the combination of modern engine test beds equipped with innovative radionuclide techniques for real-time oil consumption, oil aeration, fuel dilution, and for on-line wear measurement.

Thin Layer Activation (TLA), a radionuclide technique, was recently applied at the Research Center of ELF Solaize, France, to perform on-line monitoring of wear on diesel car engines. Measurements aimed at better understanding how wear develops on cam lobes as a function of various parameters such as lubricant formulation, soot concentration, and oil aging. The engine itself (passenger car diesel engine) was operated under severe steady state conditions (speed, torque, oil temperature and smoke) and on-line measurements were performed by applying two independent methods: direct measurement of material loss from cam lobes (inlet and exhaust valves) and concentration measurement of worn debris in oil or in the oil filter. These methods have proved to be very repeatable and absolute wear values given by TLA were consistent with those measured by profilometry.