Investigation of carbon-black emissions of a tractor biofuel diesel

Abstract

BACKGROUND: On the one hand, a petroleum-based liquid fuel diesel engine is a reliable basis for tractors and self-propelled agricultural machines, and on the other hand, the current trends make us to think about the environmental component of these diesel engines and besides to remember about reasonable use of non-renewable petroleum motor fuel. In order to reduce the anthropogenic impact on natural ecosystems and to assess the smokiness of exhaust gases from a tractor diesel running on ethanol and rapeseed oil, the paper considers the relevant model of the carbon-black formation inside it. AIM: Development of the relevant model of carbon-black emission in a tractor diesel running on ethanol and rapeseed oil to assess the smokiness of exhaust gases and to reduce anthropogenic impact on natural ecosystems. METHODS: To simulate the processes of formation and burnout of carbon-black particles in a tractor diesel engine, the volume of the combustion chamber was conditionally divided into several areas (soot content indicators in different areas were added up), and the cycle of calculating the exhaust gas smokiness level included several stages (determination of pressure, integral and differential characteristics of heat dissipation, 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 carbon-black particles, the mass of dispersed carbon, the rate of transition of particles to the burnout zone). RESULTS: The developed mathematical model is capable of calculating the carbon-black concentration and the main components of the gas mixture in the reaction zone of the combustion chamber, the content of carbon-black in the exhaust gases at various speed and load modes of operation of a tractor diesel engine. It is capable of obtaining valuable information about the dynamics of the main stages of carbon-black formation and burnout in the cylinder of a tractor diesel engine running on ethanol and rapeseed oil. The results of numerical simulation of carbon-black formation and burnout in a tractor diesel cylinder when running on diesel fuel, ethanol and rapeseed oil are obtained and presented. CONCLUSION: Based on the developed relevant model of carbon-black 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 by 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 the multi-area modeling and researches of such in-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 fuel evaporation, 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.