Dedicated exhaust gas recirculation in spark ignition engines

The impact of high levels of exhaust gas recirculation (EGR) has been well documented to decrease fuel consumption and reduce emissions of spark ignition engines. But there are also many limitations associated with this technology like EGR control and tolerance, which can reduce the potential efficiency improvements. A new concept called D-EGR has been presented in which the exhaust from a sub group of power cylinders is channeled back to the intake of all the cylinders. In this literature review both experimental and numerical analysis of this technology is shown. In the former case experiments were performed on 2.0 L PFI engine with gasoline as a fuel in part and high load conditions and the results show that at part loads the D-EGR engine can lead to lower Brake Specific Fuel Consumption, lower HC and CO emissions and higher brake thermal efficiency. At high load operations the results show improved combustion stability and superior knock tolerance. In the numerical studies it shows comparable thermal efficiency with conventional spark ignition (SI) engines and reduction in NOX emissions.