Combustion and emissions of a diesel engine utilizing novel intake manifold designs and running on alternative fuels

This work presents a number of integrated strategies aimed at enhancing the performance of the diesel engine and the subsequent reduction of its associated emissions. Three novel spiral-helical shaped intake manifolds with varying helical diameter and designs (1D, 2D, 3D, where D is the internal manifold diameter) were used to generate high turbulent kinetic energy and strong induction swirl inside the engine cylinder. The manifolds were tested using a number of alternative fuels including Gas-to-Liquid (GTL) fuel, waste cooking oil biodiesel and corn oil biodiesel in addition to blends of these fuels with conventional diesel. Manifold design (1D) exhibited superior improvements in engine performance and marked reducing in emissions irrespective of the fuel type. For high cetane-number (CN) fuels (such as GTL), a marked reduction in the pressure raise rate (dP/d theta) and the peak pressure inside the cylinder was observed. In addition, 47% reduction in NO and 32% reduction in particulate matter (PM) emissions at part load were achieved compared to amounts emitted from conventional diesel. Furthermore, using 1D manifold with high oxygen contents fuels (such as biodiesel blends) resulted in a notable reduction in the CO and HC emissions when compared to diesel fuel.