OBTAINING DIESEL FUEL WITH IMPROVED PROPERTIES

It is known that one of the ways to increase the level of operational properties of diesel fuels is the injection of special components – additives – into their composition. Today this way is a quite rational and economically feasible for Ukraine, especially in the absence of high-quality oil raw materials for the production of fuels, which in turn leads to a significant dependence on imports. The range of additives used in diesel fuels is very diverse, which makes it difficult to select a balanced package, especially considering their effectiveness and compatibility with each other. This procedure can be a bit simplified by adding poly-functional additives to diesel fuel, the use of which is devoted to a lot of periodical literature. Based on the relevance of the direction of scientific research related to improving the properties of diesel fuel, which is produced at the enterprises of the oil refining industry in Ukraine, we proposed to use a substance belonging to the class of aromatic diazocompounds and having polyfunctional properties in the composition of diesel fuels. Thus, this additive was added to a straight-run diesel fraction (240–350 °C) in an amount of up to 1.0%, followed by a study of the properties of the resulting mixture. Studies have shown that the additive significantly improves low-temperature properties (by -10 °C), contributes to an increase in fuel density and viscosity, and additionally gives diesel fuel a stable color (from yellow to orange). Consequently, it can be used in the composition of commercial diesel fuels with improved performance properties.

Numerical Study of Evaporation Modelling for Different Fuels at High Operating Conditions in a Diesel Engine

A fuel injection system in a diesel engine has different processes that affect the complete burning of the fuel in the combustion chamber. These include the primary and secondary breakups of liquid fuel droplets and evaporation. In the present paper, evaporation of two different diesel fuels has been modelled numerically. Evaporation of n-heptane and n-decane is governed by the conservation equations of mass, energy, momentum, and species transport. Results have been plotted by varying the droplet diameter and temperature. It was observed that droplet size, temperature of droplets, and ambient temperature have notable effect on the evaporation time of diesel fuel droplets in the engine cylinder.

Phenomenological Analysis of the Combustion of Gaseous Fuels to Measure the Fuel's Energy Quality and Availability to Produce Work in Si Engines, Part 2

A novel methodology is proposed to evaluate fuel´s performance in spark ignition (SI) engines based on the fuel´s energy quality and availability to produce work. Experiments used a diesel engine with a high compression ratio (CR), modified by SI operation, and using interchangeable pistons. The interchangeable pistons allowed for the generation of varying degrees of turbulence during combustion, ranging from middle to high turbulence. The generating efficiency (ηq), and the maximum electrical energy (EEmax) were measured at the knocking threshold (KT). A cooperative fuel research (CFR) engine operating at the KT was also used to measure the methane number (MN), and critical compression ratio (CCR) for gaseous fuels. Fuels with MNs ranging from 37 to 140 were used: two biogases, methane, propane, and five fuel blends of biogas with methane/propane and hydrogen. Results from both engines are linked at the KT to determine correlations between fuel´s physicochemical properties and the knocking phenomenon. Certain correlations between knocking and fuel properties were experimentally determined: energy density (ED), laminar flame speed (SL), adiabatic flame temperature (Tad), heat capacity ratio (γ), and hydrogen/carbon (H/C) ratio. Based on the results, a mathematical methodology for estimating EEmax and ηq in terms of ED, SL, Tad, γ, H/C, and MN is presented. These equations were derived from the classical maximum thermal efficiency for SI engines given by the Otto cycle efficiency (ηOtto). Fuels with MN > 97 got higher EEmax, and ηq than propane, and diesel fuels.

An Explainable DL-Based Condition Monitoring Framework for Water-Emulsified Diesel CR Systems

Despite global patronage, diesel engines still contribute significantly to urban air pollution, and with the ongoing campaign for green automobiles, there is an increasing demand for controlling/monitoring the pollution severity of diesel engines especially in heavy-duty industries. Emulsified diesel fuels provide a readily available solution to engine pollution; however, the inherent reduction in engine power, component corrosion, and/or damage poses a major concern for global adoption. Notwithstanding, on-going investigations suggest the need for reliable condition monitoring frameworks to accurately monitor/control the water-diesel emulsion compositions for inevitable cases. This study proposes the use of common rail (CR) pressure differentials and a deep one-dimensional convolutional neural network (1D-CNN) with the local interpretable model-agnostic explanations (LIME) for empirical diagnostic evaluations (and validations) using a KIA Sorento 2004 four-cylinder line engine as a case study. CR pressure signals were digitally extracted at various water-in-diesel emulsion compositions at various engine RPMs, pre-processed, and used for necessary transient and spectral analysis, and empirical validations. Results reveal high model trustworthiness with an average validation accuracy of 95.9%.