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New environmental regulations and stringent emissions standards have lowered the limits for Particulate Matter (PM) mass and Particle Number (PN) emissions requiring further optimization of gasoline direct injection (GDI) engines. Partially burned and unburned lubricating oil contributes significantly to black carbon and soot particle emissions which are not neglectable compared to fuel generated particles. Oil emissions are influenced by engine speed and load conditions but also by engine oil properties and formulation. Minimizing oil consumption has become a fundamental concern and there is a real need for better understanding associated sources and mechanisms. Therefore, researchers and engineers need appropriate tools and methodologies to solve these new problems. A reliable oil consumption measurement methodology able to quantify oil emissions (all oil emissions forms) and only oil emissions is a prerequisite.

In order to meet the particulate emission targets (6 x 1011 #/km), some gasoline direct injection (GDI) engines might require the use of particulate filters (GPF). The lifetime of wall-flow filters is influenced by the composition of the engine lubricant due to its potential to contribute to the ash accumulation in the GPF. Due to space constraints and to facilitate trapping and soot regeneration, a large number of GPFs will be in closed-coupled configuration. A study was carried out on an endurance test with a radio labelling method and conventional mass gain measurement to evaluate this GPF configuration, and verify the impact of metallic additives contained in the lubricant such as magnesium (Mg) and calcium (Ca) based detergent, a zinc (Zn) based anti-wear, and a molybdenum (Mo) based friction modifier. Two oils were evaluated, with two levels (0.85%-1.1%) of SAPS (Sulphated Ash, Phosphorus and Sulphur).