The main purpose of this research is for the investigation on the impact of engine oil formulation and aging on PM characterization from light-duty diesel engine. It is widely known that lubricant specifications and consumption from an internal combustion engine(ICE) have significantly influenced on the regulated and unregulated harmful emissions as the engine operating conditions. Especially, combustion related PM(particulate matter) and PN(particle number) concentrations in the exhaust gases were influenced by the degradation of both the engine oil and engine durability. Especially, significant increase amounts of PMs were released in the atmosphere during the diesel particulate filter(DPF) regeneration stage in advanced diesel vehicles. Moreover, determination of engine oil contribution in the exhausted PM need new measurement technique for analyzing various lubricant additives, chemical compositions, and morphology, through physical and chemical analysis methods.
From the literatures survey on advanced engine oil developing trends, engine lubricant quality standards, testing methods, and additives in Korean automotive market are comparable or surpass the worldwide engine lubricant standards. Also, establishment of new approach of PM sampling, and impact of regulated and unregulated emission gas, fuel economy, CO, PM/PN, and lubricant formulation strategy to improve environmental impact are reported.
In this research, various physiochemical analytic instruments are applied to establish the standard engine testing procedure for verifying engine oil effects on harmful emissions, especially PMs with the DPF equipped Euro 5 CRDI engine. The tested engine oils(base and genuine) are supplied from SK Lubricant(SKL) which have different oil formulation on the additives and physical properties. In addition, most widely used synthetic oils in domestic market for diesel vehicles (CRDI vehicle) is tested for assessment of lubricant effects on PM composition.
Detailed engine lubricant properties of oils are analyzed to evaluate the effects of engine oil. Also, physical and chemical analysis with SEM(Scanning Electron Microscope), EDS(Energy-dispersive X-ray Spectroscopy), XPS(X-ray Photoelectron Spectroscope) are applied to quantify the engine oil contribution on PM composition that are sampled onto quartz filters using specially designed PM sampling equipments. The physiochemical characteristics of the real-world aged DPFs around 130,000 km were assessed to inspect soot/ash accumulation in the DPF channels sites. Especially, engine oil-derived soot/ash compositions deposited in the DPF was throughly analyzed by X-CT(X-ray Computerized Tomography), SEM, EDS, XPS, and XRD(X-ray Diffractometer).