Effect of Premixed Diesel Fumigation on Performance and Emissions Characteristics of Homogenous Charge Compression Ignition Engine

The effect of premixed diesel fumigation (PDF) on performance and emissions characteristics of Homogenous Charge Compression Ignition (HCCI) engine and optimisation of the diesel fumigation temperature are prime focus of this study. The experimental investigations were carried on single cylinder, four stroke, water cooled, port injected Kirloskar SV1 engine. For this research, the engine was modified as HCCI engine with electric air heater, fixed at suction pipe. During the experimental investigation the diesel fuel was premixed by the port injector and vaporised or fumigated the fuel by heated suction air. After heating process, the diesel has changed its phase and mixed with air and form partially homogenous mixture. During the test, the engine was operated with different diesel fumigation temperature from 100°C to 150°C in steps of 10°C and observed the performance and emissions characteristics of the engine. The effective diesel fumigation temperature for creating better homogeneous charge is identified. The diesel fumigation made huge impact on NO_x and smoke formation. The level of NO_x and smoke emissions were decreased simultaneously as 10% and 16% compared to compression ignition (CI) engine. At the same time, the HCCI engine has emitted high CO and HC emissions at low fumigation temperatures and they were reduced at high fumigation temperatures, because of improved combustion. The suction air temperatures of 120°C and 130°C for the HCCI engine registered low NO_x and smoke emissions. From the performance point of view, the HCCI engine consumed much more fuel due to low volumetric efficiency and slightly affected the brake thermal efficiency.