Effect of port injection pressure on mixture quality in Homogeneous charges compression ignition (HCCI) engine

The purpose of this study is to investigate the effect of fuel injection pressure on homogeneous charge formation and performance and emission characteristics of Homogeneous charge compression ignition engine. The fuel injection pressure is one of the primary parameter for improving the homogeneity of the mixture and governing the power output and emission characteristics of HCCI engine. In this investigation, diesel fuel was injected at different injection pressures as 2bar, 3bar, 4bar and 5bar respectively through by port fuel injector. The experimental investigations show that increasing the fuel injection pressure will promote the fuel to penetrate with air and creates well pre mixed air/fuel charge. The result shows, the specific fuel consumption (SFC) of HCCI engine is slightly higher than the SFC of conventional diesel engine. The HCCI engine with 3bar injection pressure operated engine has lower SFC values compared to other injection pressure operated HCCI engine. The brake thermal efficiency of HCCI engine, operated with 3bar injection pressure has maximum BTE values over the other injection pressure operated engine. From the result, it is observed that HCCI engine has lower smoke density values compared to conventional diesel engine and further reduced by increasing the fuel injection pressure. The 3bar injection pressure operated HCCI engine has emitted lower smoke density compared to other injection pressure operated HCCI engine. The 3bar injection pressure operated HCCI engine has emitted maximum oxides of nitrogen (NOx) emissions than the other injection pressure operated HCCI engine. Other exhaust emissions of carbon monoxide (CO) and hydrocarbon (HC) emissions are increased when compared to convention diesel engine