Advanced combustion processes or low temperature combustion processes make it possible to achieve lower nitrogen oxide (NOx) and particulate matter (PM) emissions in comparison to conventional combustion processes with comparable engine efficiency. The use of suitable alternative fuels with a high ratio of H:C number of atoms contributes to lower carbon dioxide (CO2) emissions. In low temperature combustion processes with high homogenization level of the working mixture, the most researched are Homogeneous Charge Compression Ignition (HCCI), Partially Premixed Compression Ignition (PPCI) and Reactivity Controlled Compression Ignition (RCCI), of which the latter being analyzed in this diploma work. For RCCI combustion process, the influence of changing injection timing of the hydrotreated vegetable oil and petrol mixture (HVO/b) in 75 %/25 % ratio, temperature in intake manifold and the exhaust gas recirculation (EGR) fraction on pollutant emissions, various thermodynamic parameters and engine efficiency were investigated. Achieved PM emissions are always significantly lower compared to basic Diesel engine controlled by the original engine control unit. Early injection of HVO/b has beneficial influence on reducing NOx emissions and raising engine efficiency, but raises hexane (HC6) and carbon monoxide (CO) emissions. EGR has proven as a suitable system to control NOx emissions and combustion delay. The same effect on the combustion period and NOx emissions is also noticable when the temperature in the intake manifold is lowered.
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