Particles Morphology of Mechanically Generated Oil Mist Mixtures of SAE 40 Grade Lubricating Oil with Diesel Oil in the Context of Explosion Risk in the Crankcase of a Marine Engine

Abstract

This article presents research results on mechanically generated oil mists. The research was carried out for oil mixtures for the Agip/Eni Cladium 120 SAE 40 API CF oil for industrial and marine engines diluted with diesel oil Orlen Efecta Diesel Bio at diesel oil concentrations of 2%, 5%, 10%, 20%, and 50% m/m. Pure lubricating oil and pure diesel oil were also tested. Droplet size distributions were determined for the reference moment at which residual discrepancies R between the measurement data and the sprayed pure diesel oil calculation model obtained the lowest value. For mechanically generated oil mists, the light transmission coefficient through the oil mist T, the specific surface area of the oil mist SSA, and the volumetric share of drops DV(V%) for 10%, 50%, and 90% of the total volume of the generated oil mist were determined. The span of the volumetric distributions of droplet sizes SPAN, Sauter mean diameter D[3,2], De Brouckere mean diameter D[4,3], the volumetric and mass percentage of droplets with diameters ≤5 μm (diameters necessary for a crankcase explosion), the minimum difference between the measurement results, and the calculation model used by the residual error measuring device were determined. The best fit in each measurement cycle (the smallest R value was analyzed. For specific indicators, correlations with diesel oil levels in the mixture were determined using the Pearson rXY linear correlation coefficient. Those results confirmed an increase in smaller-diameter droplets, an increase in the number of droplets with diameters up to 5 μm, and an increase in the span of the oil mist droplet diameter distribution with additional diesel oil. This confirmed a relationship between an increased lubricating oil dilution and an increased explosion risk in the crankcase.

Assessment of the Impact of Lubricating Oil Contamination by Biodiesel on Trunk Piston Engine Reliability

“…At the same time, given the decrease in viscosity and, thus, the deterioration of the lubrication conditions and the reduction in the evaporation and ignition temperatures, one can conclude that the synergistic interaction of these factors increases the risk of explosion in the engine crankcase. Previous work [23] has presented a middle ground for the earlier-mentioned extreme opinions regarding the impact of diesel oil contamination on engine performance and, simultaneously, the obtained results show that diesel oil levels are above 10% when oil film rupture occurs and can be classified as critical.…”

“…Simultaneously, in [23], an analysis of the selected quantities describing the tribological properties of the mixture is carried out, namely, the results of the mixture's lubricity tests that are performed with the use of a High-Frequency Reciprocating Rig (HFFR). At the same time, additional parameters obtained during this test are analyzed.…”

“…In turn, the increase in these forces causes a growth in the temperature at the interface of the cooperating bodies [65]. The local temperature rises within the crankcase are referred to as hot spots; they are one of the elements of the oil mist formation [23] in the crankcase space that, when concentrated inside an explosive area, may explode when in contact with the elements when temperatures exceed the ignition temperature [66]. For both mixtures of the tested lubricating oils with SAE 30 and SAE 40 grades, an increase in the value of the average coefficient of friction between the samples (separated by these mixtures during the lubricity test at the HFFR stand) is observed.…”

Modeling of Selected Parameters of Used Lubricating Oil Diluted with Diesel Oil Using the Characteristics of Fresh Lubricating Oil

“…surface acoustic wave sensing (SAW) (ASTM D8004-15 [23], ASTM D8004-23 [24]), • gas chromatography coupled with mass spectrometry (GC-MS) [6], ultraviolet (UV) spectrofluorimetry [7,25,26],…”

Arrhenius Equation for Calculating Viscosity in Assessing the Dilution Level of Lubricating Oil with Diesel Oil—A Case Study of SAE 30 and SAE 40 Grade Marine Lubricating Oils

“…One of the threats that may occur during the operation of marine piston combustion engines is the deterioration of lubrication conditions, which is influenced by the design [1][2][3] and technical condition of the engine [4][5][6], and type of oil [7][8][9] and fuel [10][11][12] with which the engine is powered. There are many research results devoted to assessing the efficiency and reliability of internal combustion engines with contaminated circulating lubricating oil (LO) [13][14][15], including fuel-diluted lube oil (both distillation and residual) [16][17][18]. Operating experience and test results clearly show that diluting LO with fuel is unfavorable for the engine, deteriorating the engine's operating efficiency, shortening the life of the oil, and reducing the reliability and safety of the engine [19,20].…”