Biodiesel Production Using Modified Direct Transesterification by Sequential Use of Acid-Base Catalysis and Performance Evaluation of Diesel Engine Using Various Blends

Biodiesel is a seemingly suitable alternative substitute for conventional fossil fuels to run a diesel engine. In the first part of the study, the production of biodiesel by modified direct transesterification (MDT) is reported. An enhancement in the biodiesel yield with a considerable reduction in reaction time with the MDT method was observed. The required duration for diesel and biodiesel blending was minimized including glycerol separation time from biodiesel in the MDT method. The development in the automotive sector mainly focuses on the design of an efficient, economical, and low emission greenhouse gas diesel engine. In the current experimental work Ceiba pentandra/Nigella sativa and diesel blends (CPB10 and NSB10) were used to run the diesel engine. A variety of approaches were implemented to improve the engine performance for these combinations of fuels. The fuel injector opening pressure (IOP) was set at 240 bar, the torriodal re-entrant combustion chamber (TRCC) having a six-hole injector with a 0.2 mm orifice diameter each, provided better brake thermal efficiency (BTE) with lower emissions compared with the hemispherical combustion chamber (HCC) and trapezoidal combustion chamber (TCC) for both CPB10 and NSB10. CPB10 showed better performance compared with NSB10. A maximum BTE of 29.1% and 28.6% were achieved with CPB10 and NSB10, respectively, at all optimized conditions. Diesel engine operation with CPB10 and NSB10 at 23° bTDC fuel injection timing, and 240 bar IOP with TRCC can yield better results, close to a diesel run engine at 23° bTDC fuel injection timing, and 205 bar IOP with HCC.

Particulate Emission Reduction by Fuel Injection Timing Optimization in a Gasoline Direct Injection Engine

Optimized fuel injection timings in internal combustion (IC) engines exhibit superior performance, combustion characteristics, and lower emissions. Particularly, particulate emissions from a gasoline direct injection (GDI) engine are highly dependent on fuel injection timings. GDI engines have emerged as a popular choice of powerplants for automobiles among customers. They are preferred over multiple-port fuel injection (MPFI) engines in the transport sector because of their superior fuel economy and performance characteristics. The main objective of this study was to optimize a GDI engine for the lowest particulate emission at different fuel injection timings. GDI engine was investigated for particulate matter (PM) mass/ particulate number (PN) emissions at five fuel injection timings (230, 250, 270, 290, 310 °btdc), which covered the entire envelope. Once the optimum fuel injection timing was determined, an engine exhaust particle sizer was used to measure the particle size-number distribution. Particulate samples from the engine were also collected on the filter paper for morphological investigations of particulates collected under optimized fuel injection timings. These experiments confirmed the importance and need to optimize the fuel injection timings at every engine operating point to reduce the PM/PN emissions from a GDI engine, which remains one of the biggest challenges to this technology.