Development of Theta II 2.4L GDI Engine for High Power & Low Emission 2009-01-1486
Flow and wall guided gasoline direct injection engine was developed for decreasing fuel consumption in vehicle by operating engine in the stratified lean air fuel ratio and reducing Nitrogen Oxides by applying the system of exhaust gas recirculation in the part load. However, it needed an expensive lean NOx catalytic converter and low Sulfur gasoline. So, they are not successful because of higher cost of lean NOx catalytic converter and lower gain in fuel economy in the higher emission level. Yet, Homogeneous GDI engine fulfills demands for higher specific power output in full load over port injection gasoline engines by intake air cooling and shows the enhanced fuel economy by higher compression ratio and internal exhaust gas recirculation in part load. Also, Gasoline direct injection inside cylinder leads to the cost reduction of catalytic converter by reducing Hydro Carbon and NOx exhausted until catalyst light off from engine start and shortening light off time. So, Most of OEM are mass producing and developing the naturally aspirated and turbocharged homogeneous GDI engines. They meet the existing and future emission legislation in lower cost and higher power compared with flow and wall guided GDI engines.