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Reduction of fuel consumption and pollutant emissions are key factors in the current development of powertrains. Engine oil has proven to be an efficient lever for improving fuel economy. The full potential of a low viscosity lubricant could be achieved by a shift towards formulations with low viscosity, high volatility base oils. However, there is a concern that this might increase oil consumption and limit long oil drain intervals. This article deals with the engine lubricant contribution to oil and particle emissions. A series of 0W-12 oil prototypes have been evaluated both within laboratory measurements and on a modern turbocharged direct injection gasoline engine. Correlation between oil emission and engine oil properties will be presented. The impact of engine oil on particle emissions has also been investigated under different engine operating conditions.

In the present paper the results of a set of experimental investigations on LSPI are discussed. The ignition system of a test engine was modified to enable random spark advance in one of the four cylinders. LSPI sequences were successfully triggered and exhibited similar characteristics compared to regularly occurring pre-ignition. Optical investigations applying a high speed camera system enabling a visualization of the combustion process were performed. In a second engine the influence of the physical properties of the considered lubricant on the LSPI frequency was analyzed. In addition different piston ring assemblies have been tested. Moreover an online acquisition of the unburned hydrocarbon emissions in the exhaust gas was performed. The combination of these experimental techniques in the present study provided further insights on the development of LSPI sequences.