Experimental investigation of porous media combustion applied on the piston bowl of diesel engine

The attainment of homogenous combustion in diesel engines has always been a challenge. The erstwhile literatures reported the potential of porous media (PM) in enhancing the homogeneity of fuel-air mixture in various combustion devices. Taking cognisance of this fact, it was attempted to apply PM on the piston bowl of the diesel engine to study the consequent efficacy of homogenous combustion. It was revealed from the study that with the application of PM on the piston bowl, the evaporation rate of the fuel mixture was enhanced (shorter ignition delay) and mechanical efficiency was also improved as compared to the conventional engine. Compression tests were performed for the three commercially available PMs, like silicon carbide, alumina and zirconia, to determine their load bearing capacity inside the engine during operation. Silicon carbide was found to have better material strength to resist load. Also, experimental analysis was conducted by the use of cylindrical shaped silicon carbide fixed in the cylindrical piston bowl, which was modified from the traditional hemispherical one. The standard volumetric compression ratio of 17.5 and the porosity of similar to 78% were considered for PM. The experiments were performed at different part loads with PM for the safe operation of the engine. The mechanical efficiency (eta m) was found to enhance by similar to 9% and ignition delay got advanced by similar to 2 degrees crank angle with PM. Emission parameters with PM, such as nitrogen oxides (NOX) and carbon dioxide (CO2) were reduced up to similar to 62% and similar to 39%, respectively, than those of conventional diesel engine. [GRAPHICS] .