Combustion chamber geometry and fuel supply system variations on fuel economy and exhaust emissions of GDI engine with EGR

Abstract

In this study, the combustion chamber geometry for spray-guided, wall-guided, and air-guided combustion strategies were fabricated. The piston crown shape and the cylinder head in each combustion chamber geometry was machined by fixing the fuel injector and spark plug at proper positions to obtain swirl, turbulence, and squish effects for better mixing of fuel with air and superior combustion of the mixture. Conducted tests on all the three modified gasoline direct injection engines with optimized exhaust gas recirculation and electronic control towards fuel injection timing, the fuel injection pressure, and the ignition timing for better the performance and emissions control. It is clear from the results that NOx emissions from all three combustion modes were reduced by 4.9% upto 50% of loads and it increase for higher loads due to increase of in-cylinder pressure. The fuel consumption and emissions showed better at 150 bar Fuel Injection Pressure for wall-guided combustion chamber geometry. Reduced HC emissions by 3.7% and 4.7%, reduced CO emissions by 2% and 3.3%, reduced Soot emissions by 6.12% and 10.6%. Reduces specific fuel consumption by about 10.3% and 13.3% in wall-guided combustion strategy compare with spray-guided and air-guided combustion modes respectively.