No abstract

The significance of the paper is confirmed by the need to replace petroleum motor fuels with fuels produced from alternative energy sources. Biofuels derived from various vegetable resources are considered as promising alternative fuels for diesel engines. These fuels offer significant advantages with respect to the renewability of their raw materials and good emission performances when burned in ICEs. The main problem of using vegetable oils as biofuels for diesel engines is their high viscosity. This problem can be resolved by using mixed biofuels with the addition of gasoline. The analysis of physico-chemical properties of petroleum diesel fuel (DF) and mixed biofuels containing petroleum DF, rapeseed oil (RO) and AI-80 automotive gasoline was conducted. Experimental studies of the D-245.12S diesel fuelled with these mixed fuels were carried out. The mixed fuels were prepared from 80% DF + 20% RO, from 75% DF + 20% RO + 5% AI-80, and from 70% DF + 20% RO + 10% AI-80. It was shown that the addition of gasoline to mixed biofuels could improve two main toxicity indicators of exhaust gases exhaust gases smoke and emissions of nitrogen oxides. The best emission performance was achieved for the mixture of 70% DF, 20% RO and 10% AI-80. When the diesel engine was switched from the mixture of 80% DF and 20% RO to the mixture of 70% DF, 20% RO and 10% AI-80, the exhaust gases smoke at maximum torque mode decreased from 17.5 to 14.5% on the Hartridge scale, i.e. by 17.1%. The specific emissions of nitrogen oxides decreased from 6.559 to 6.154 g/(kW·h), i.e. by 6.2%.

The article discusses the possibility of using blended biofuels from rapeseed oil (RO) as fuel for a diesel engine. RO blended diesel fuel (DF) and emulsified multicomponent biofuels have been investigated. Fuel physicochemical properties have been analyzed. Experimental tests of a diesel engine D-245 in the operating conditions of the external characteristic curve and the 13-mode test cycle have been conducted to investigate the effect of these fuels on engine performances. CFD simulations of the nozzle inner flow were performed for DF and ethanol-emulsified RO. The possibility of a significant improvement in brake thermal efficiency of the engine has been noted. The efficiency of using blended biofuels from RO as a motor fuel for diesel engines has been evaluated based on the experimental test results. It was shown that in comparison with the presence of RO in emulsified multicomponent biofuel, the presence of water has a more significant effect on NOx emission reduction. The content of RO and the content of water in the investigated emulsified fuels have a comparable influence on exhaust smoke reduction. Nozzle inner flow simulations show that the emulsification of RO changes its flow behaviors and cavitation regime.

This study addresses the problem of selecting the optimal structure and parameters of an electronic rotational speed controller for the crankshaft of a locomotive engine. An electronic control system of fuel supply ESUVT.01 developed by OOO PPP Dizelavtomatika (Saratov) for the locomotive diesel engine D50 manufactured by OAO Penzadizelmash is presented in the paper. Experimental studies were conducted to evaluate the impact of the structure and parameters of the system on dynamic properties of the engine. Bench tests were conducted on a diesel generator unit 1-PDG4D consisting of a diesel engine D50 and a traction generator MPT-84/39. As the result of the testing, equations describing dependencies of the transient process duration, overspeeding during the transient process and the free period on the parameters of the proportional-and-integral controller were obtained. The study confirmed the need to optimise the values of the coefficients of the proportional and integral components of the proportional-and-integral governing law and adjust them in accordance with the operational mode of the diesel engine. An appropriate optimisation method was proposed. Optimised values of these coefficients for the transient process of the studied diesel engine acceleration with regard to the locomotive characteristic were obtained.

The fuel economy and exhaust emissions of diesel engines can be improved by adding carbon nanotubes to petroleum diesel fuel. Carbon nanotubes, used as a promising nanoscale additive for diesel fuel, have high thermal conductivity and a large surface area to volume ratio. The thermophysical properties of these fuels, which depend on the composition of the mixtures, are analyzed in this study. Findings of research show that carbon nanotubes added to diesel fuel have little effect on its dynamic viscosity and thermal conductivity. By means of numerical models, we simulated the process of atomization and evaporation of diesel fuel with the different carbon nanotubes content in a constant volume combustion chamber. The accuracy of the calculations is confirmed by the good agreement between the calculated and experimental data. Simulation of mixture atomization showed that the jet length linearly depends on the carbon nanotubes content in diesel fuel. The more carbon nanotubes are in the mixture, the smaller the droplet Sauter mean diameter and the angle of the jet cone opening are. The presence of carbon nanotubes in diesel fuel insignificantly affects the fuel vapor content in it.