External mixture formation (PFI) of a diesel fuel aerosol has employed to investigate the diesel\nHCCI engine combustion and emissions characteristics. The key to the external mixture formation\nwith diesel fuel is the proper fuel/air mixture preparation. A proposed intake diesel fuel aerosol\nsystem mainly consists of a small chamber, in which the diesel fuel is fully vaporized by means of\nfuel cavitation inside the diesel injector nozzle. Nozzle cavitation is mainly affected by the injection\npressure and the fuel system temperature. Results obtained reveal that the proposed method\ndetermines the possibility of producing a complete homogeneous fuel/air mixture, which can be\napplied to the diesel HCCI engine. With this method, the combustion and emission behavior were\nentirely optimized and the engine is capable of running in HCCI combustion mode with nearly\nideal mixture preparation. In the present investigation, a methodology for the HCCI combustion\nmode of the diesel aerosol/air mixtures based on the fuel cavitation inside the injector nozzle parameters\n(such as the injection pressure and the fuel system temperature where fuel premixed\nratio, NOx, CO, CO2, and HC emissions) have analyzed. Based on the engine performance and emissions\ncharacteristics the fuel injection pressure and the fuel system temperature have optimized\nto produce a suitable fuel premixed ratio and the perfect fuel/air mixture homogeneity at different\nengine operating conditions. The optimal injection pressure ranges between 150 - 200 bars,\nwhile the fuel system temperature lies within 175C - 200C. Loops of exhaust gas recirculation\n(EGR) are used to extend the engine load by controlling the combustion phasing.
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