A b s t r a c t . HCCI (Homogenous Charge Compression Ignition) combustion system is now one of the most promising solutions used in piston engines. The paper presents the results of three-dimensional modeling of combustion in the singlecylinder HCCI engine powered with Diesel fuel. 3D modeling was performed in AVL Fire code. The basic combustion parameters including start of the ignition (SOI), burn duration (BD), indicated pressure (pi) and nitric oxide (NO) and soot (Soot) emissions were analyzed. The modeling results show that combustion process in HCCI engine compared to a conventional engine with compression ignition is characterized by an earlier ignition (SOI) and shorter burn duration (BD). The impossibility of controlling HCCI combustion process leads to deterioration of engine performance and increased emissions of harmful exhaust gas components. Calculations showed that for the same equivalence ratio of burn mixture, uncontrolled HCCI combustion compared to a controlled combustion in engine with fuel injection operated is characterized by higher NO emission and reduced Soot emission.
Key words: homogenous charge compression ignition (HCCI), exhaust gas recirculation (EGR), heat release rate (HRR), start of the ignition (SOI), burn duration (BD), injection timing (IT), conventional compression ignition engine (CI), indicated pressure (pi), nitric oxide (NO).