Thermo-gravimetric study of the crankcase gases composition

Abstract

Introduction (problem statement and relevance). The paper presents the experimental results of crankcase gas (CG) condensate. The condensate was obtained during engine testing due to a special driving cycle. After holding at rest for 24 hours, the condensate separated into three parts: lower “A”, approximately 12%vol - water; medium “B”, about 6%vol - water-oil emulsion; upper “C”, about 82%vol - the mixture of condensed hydrocarbon vapors and solid particles.The purpose of the research was to determine the weight ratio of fuel and oil components in the CG.Methodology and research methods. In this work, the thermo-gravimetric research method (TGA -Thermo-gravimetric analysis) was used, the purpose of which was to determine the change in the test sample mass depending on temperature and time. The condensate was evaporated at T = 200°C. At this temperature all fuel fractions, including the tail fractions, evaporated completely, but the oil, if it was present in the condensate, evaporated in an extremely small amount.Scientific novelty and results. The results of the “C” upper part dispersal (evaporation) showed that with a well-designed and properly functioning crankcase ventilation system (CVS), the composition of the CG contained mainly heavy fuel fractions. In the studied part “C”, fuel fractions accounted for 96.3%wt, while the rest composed 3.7%wt, being a thick, pasty black precipitate with a specific smell of aromatic hydrocarbons. It was the first time when TGA was used to study the composition of CG, and highly accurate data was presented as a result.Practical significance. On the basis of TGA, a methodology for validation tests of ICS has been developed. The absence or low content of oil in the composition of the remnants is a criterion for a positive functional assessment of the CVS. The TGA also allows to evaluate the CVS quantity effect on oil consumption. The residue isolated during the research is a building material for the formation of the so-called “soot coat” on the plate and the intake valve stem from the intake channel.