Reduction of Soot Emission at a DI Diesel Engine by Additional Injection of Hydrogen Peroxide During Combustion

We will introduce two methods with which hydrogen peroxide (H₂O₂) is injected into the combustion chamber of a DI Diesel engine during main time of combustion. One method is using a second injection system to inject the H₂O₂ and the other method is the injection of a fuel-H₂O₂ emulsion into the combustion chamber. Hereby the emission of soot can be considerably reduced without a large influence to NO_x, even with the second method a reduction of NO_x is measured. From calculations on soot kinetics and measurements it is known that the majority of soot is already being oxidized within the cylinder itself. Considering the high temperatures during the combustion, it is mainly the OH radical that leads to soot oxidation. By injecting H₂O₂ and in this way increasing the concentration of OH later on during the combustion, soot can almost completely be reduced provided that there is an ideal mixture.