Analysis of oil consumption in cylinder of diesel engine for optimization of piston rings

Abstract

The performance and particulate emission of a diesel engine are affected by the consumption of lubricating oil. Most studies on oil consumption mechanism of the cylinder have been done by using the experimental method, however they are very costly. Therefore, it is very necessary to study oil consumption mechanism of the cylinder and obtain the accurate results by the calculation method. Firstly, four main modes of lubricating oil consumption in cylinder are analyzed and then the oil consumption rate under common working conditions are calculated for the four modes based on an engine. Then, the factors that affect the lubricating oil consumption such as working conditions, the second ring closed gap, the elastic force of the piston rings are also investigated for the four modes. The calculation results show that most of the lubricating oil is consumed by evaporation on the liner surface. Besides, there are three other findings: (1) The oil evaporation from the liner is determined by the working condition of an engine; (2) The increase of the ring closed gap reduces the oil blow through the top ring end gap but increases blow-by; (3) With the increase of the elastic force of the ring, both the left oil film thickness and the oil throw-off at the top ring decrease. The oil scraping of the piston top edge is consequently reduced while the friction loss between the rings and the liner increases. A neural network prediction model of the lubricating oil consumption in cylinder is established based on the BP neural network theory, and then the model is trained and validated. The main piston rings parameters which affect the oil consumption are optimized by using the BP neural network prediction model and the prediction accuracy of this BP neural network is within 8%, which is acceptable for normal engineering applications. The oil consumption is also measured experimentally. The relative errors of the calculated and experimental values are less than 10%, verifying the validity of the simulation results. Applying the established simulation model and the validated BP network model is able to generate numerical results with sufficient accuracy, which significantly reduces experimental work and provides guidance for the optimal design of the piston rings diesel engines.

Lubricating Oil as a Major Constituent of Ship Exhaust Particles

“…This may lead to an increased rate of oil evaporation from the cylinder liner during the expansion stroke, which is when most of the oil evaporates from the engine. 36,37 Finally, we also conclude that potential biological effects of lubrication oil components should be investigated in closer detail (e.g., in air−liquid−interface exposure experiments 29 ).…”

“…Stengel et al recently observed on the same engine that MGO ignites before the top dead center of the piston, while HFO ignites only after the top dead center. This may lead to an increased rate of oil evaporation from the cylinder liner during the expansion stroke, which is when most of the oil evaporates from the engine. , …”

Investigation of oil emission mechanisms in a marine medium-speed dual-fuel engine

“…Since particulate emissions in diesel engines are dominated by unburnt fuel emissions (e.g. soot), research is more focussed on fuel-oil interaction and lube oil consumption rather than oil emissions, as seen in Zhang et al, 14 Pasligh et al 15 Due to the mechanisms being related, findings also show the above-mentioned necessity to co-develop piston rings and cylinder liners.…”