Avtomobilʹnyj Transport (Harʹkov) (Jun 2018)
INFLUENCE OF FUEL SUPPLY PARAMETERS AND EXHAUST GAS RECIRCULATION ON DIESEL EMISSIONS
Abstract
Diesel engines used in road transport and other power plants are the sources of environmental pollution. Therefore, it is necessary to search for new approaches to the working process organization that allow reducing emissions of harmful substances in exhaust gases: nitrogen oxides (NOx), carbon oxides (CO), hydrocarbons (THC) and particulate matter (PM). Problem. The most difficult problem to fulfil the standard requirements to the emission of harmful substances in exhausted gases of diesel engines is simultaneous reduction of nitrogen oxides (NOx) and particulate matter (PM), due to the fact that these parameters are inversely related. Goal. The purpose of the research is to improve the ecological and fuel-economic parameters owing to working process improvement, determine the engine rational adjustment parameters: fuel injection pressure; fuel injection advance angle; degree of recirculation of exhaust gases; design parameters: the shape of the combustion chamber and the configuration of the injector nozzle, the controlled exhaust gases recirculation (EGR) over the high pressure circuit with cooling of the bypassed exhaust gas. Methodology. To choose adjusting parameters of the fuel supply system and the EGR, modeling of working process at all characteristic points of the NRSC cycle is carried out. Results. The minimum NOx emission at a different PM level is realized by changing the fuel injection pressure, the fuel injection advance angle and the EGR degree that is in the lower range of the study boundaries. Reduction of specific effective fuel rate at the nominal mode has been obtained due to the used EGR at the level of 8-11%. Originality. Based on the results of the research, the regressive dependencies of the change in the evaluation parameters NOx, PM, ge on the adjusting parameters (fuel injection pressure, the fuel injection advance angle and the EGR degree) which contribute to reducing fuel consumption and decreasing emissions of harmful substances from exhaust gases have been constructed. Practical value. Adjustment parameters which ensure the particulate matter emission corresponding to the level of Stage 4 have been obtained.
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