IMPACT OF OPERATING PARAMETERS ON ENERGY EFFICIENCY AND REGULATED EMISSIONS OF DUAL FUEL DIRECT INJECTED REACTIVITY-CONTROLLED COMPRESSION-IGNITION COMBUSTION

Abstract

ABSTRACT In the current investigation, a modified non-road naturally aspirated conventional RCCI (i.e., PFI RCCI) engine has been replaced with low-pressure gasoline and high-pressure diesel dual fuel direct injection (DFDI) system and successfully investigated. Direct injection of low and high Cetane number fuels enhanced the in-cylinder stratification of the injected fuels and decreased the gasoline contact with the crevice region. Detailed tests have been conducted on the DFDI engine by sweeping the operating parameters, such as gasoline energy ratio (GER), the number of gasoline/diesel injection, gasoline/diesel mass and exhaust gas recirculation (EGR). The experimental results indicated that DFDI RCCI combustion increased the combustion efficiency by 8% and brake thermal efficiency (BTE) by 3% compared to conventional RCCI combustion. The simultaneous reduction in NO and Soot emission was observed in DFDI RCCI. Also, hydrocarbon (HC) and carbon monoxide (CO) emissions decreased by about 35% and 12%, respectively, in DFDI RCCI than conventional RCCI combustion. The results indicated that each parameter had an impact on the BTE and emission characteristics of DFDI RCCI, particularly GER and EGR. Abbreviations: aTDC: after Top Dead Center; bTDC: before Top Dead Center; BTE: Brake Thermal Efficiency; CA: Crank Angle; CDC: Conventional Diesel Combustion; CE: Combustion Efficiency; CO: Carbon Monoxide; COV: Coefficient of Variation; DDFS: Dual Direct Fuel Stratifications; DFDI: Dual Fuel Direct Injection; DGI: Double Gasoline Injection; DIP: Diesel Injection Pressure; EGR: Exhaust Gas Recirculation; GDI: Gasoline Direct injection; GER: Gasoline Energy Ratio; GIP: Gasoline Injection Pressure; HC: Hydrocarbon; HCCI: Homogeneous Charge Compression Ignition; HR: High reactivity; IMEP: Indicated Mean Effective Pressure; ITE: Indicated Thermal Efficiency; LTC: Low-Temperature Combustion; LR: Low reactivity; NO: Nitric Oxide; NOx: Oxides of Nitrogen; PCCI: Premixed Charge Compression Ignition; PFI: Port Fuel Injection; PPCI: Partial Premixed Charge Ignition; RCCI: Reactivity Controlled Compression Ignition; RoHR: Rate of Heat Release; RoPR: Rate of Pressure Rise; SGI: Single Gasoline Injection; SOI-1: HRF first pulse start angle; SOI-1mass:HRF first pulse mass quantity; SOI-2: HRF Second pulse start angle