The reduction of pollutant emissions in internal combustion engines can be achieved either through the use of exhaust aftertreatment systems or with the introduction of advanced combustion processes. Exhaust aftertreatment systems increase engine cost, therefore, advanced low-temperature combustion processes are being intensively investigated to allow simultaneous achievement of lower NOx and particulate matter (PM) emissions compared to conventional diesel combustion processes while achieving comparable indicated efficiency. An additional reduction in CO2 emissions can be achieved by using alternative fuels, such as hydrogenated vegetable oil (HVO) and biomethane, whose use in low-temperature combustion processes is analyzed in this thesis. For reactivity controlled compression ignition (RCCI), which represents one of the low-temperature combustion processes, the influence of different mixtures of high and low reactive fuel and the proportion of recirculated exhaust gases on the thermodynamic combustion parameters, the indicated engine efficiency and the pollutant emissions are investigated. In the RCCI combustion process, simultaneously achieved emissions of NOx and PM were significantly lower than can be simultaneously achieved in a conventional diesel combustion process. With the use of HVO, NOx and PM emissions were slightly higher, carbon monoxide (CO) and unburned hydrocarbon (THC) emissions were reduced compared to the emissions achieved with diesel in the RCCI combustion process. Based on to the results of the analyzes, the use of HVO instead of conventional diesel in low-temperature combustion processes contributes to a lower carbon footprint.
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