Investigation of carbon black emissions in tractor diesel powered by biofuels

Abstract

BACKGROUND: On the one hand, a diesel engine running on liquid fuel of petroleum origin is a reliable basis for tractors and self-propelled agricultural machines, and on the other hand, the realities of modern times force us to think about the environmental component of these diesel engines, and besides, do not forget about the economy of that non-renewable petroleum motor fuel. In order to reduce the anthropogenic impact on natural ecosystems and assess the smokiness of exhaust gases from tractor diesel powered by ethanol and rapeseed oil, the paper considers a modern model of the formation of soot content in it. AIMS: development of a modern model of soot emission in a tractor diesel powered by ethanol and rapeseed oil to assess the smokiness of exhaust gases and reduce anthropogenic impact on natural ecosystems. METHODS: To simulate the processes of formation and burnout of soot particles in a tractor diesel engine, the volume of the combustion chamber was conditionally divided into several zones (soot content indicators in different zones were added up), and the cycle of calculating the exhaust gas smoke level included several stages (determination of pressure, integral and differential characteristics of heat release, average temperature of the working fluid, fuel supply indicators and fuel evaporation rate, local coefficients of excess air, composition of gases, concentration of decomposition and oxidation products of rapeseed oil and ethanol, the number of soot particles, the mass of dispersed carbon, the rate of transition of particles to the burnout zone). RESULTS: The developed mathematical model allows us to calculate the concentration of soot and the main components of the gas mixture in the reaction zone of the combustion chamber and the content of soot in the exhaust gases at various speed and load modes of operation of a tractor diesel engine, to obtain valuable information about the dynamics of the main stages of soot formation and burnout in the cylinder when a tractor diesel engine is running on ethanol and rapeseed oil. The results of numerical simulation of soot formation and burnout in a tractor diesel cylinder when running on diesel fuel, ethanol and rapeseed oil are obtained and presented. CONCLUSIONS: Based on the developed modern model of soot emission in a tractor diesel engine running on ethanol and rapeseed oil, an assessment of its exhaust gas smokiness was carried out, clearly showing a decrease of 3.4-3.8 times in comparison with diesel fuel operation. The presented method for calculating the carbon black emission of tractor diesel can be used in multi-zone modeling and research of such intra-cylinder processes as heat generation, heat transfer, etc. The accuracy of calculations based on the proposed model is characterized by the perfection of mathematical algorithms describing the rate of evaporation of fuel, the development of a fuel flare, the determination of local temperatures, the rate of flame propagation, the local composition of gases in the cylinder, etc.