NOVEL CATALYTIC CONVERTER OXIDE FOR SI ENGINES

Subject of the paper are converters of lean mixtures for SI engines wi th a good efficiency of NOx reduction. Investigation of new effective catalytic mater ials having good sorptive propriet ies of nitrogen oxi des and simultaneously resistant on the ther mal destruction and chemical destruction are main aim of t he paper. The operating idea of such converters and conditions of their work are also presented. Main objective of the paper is performance of the new re actor of the Pt/Rh-MgO/CeO2/Al2O3 formula. The magnesium oxide MgO is here an absorber of nitrous oxi des and has an essential feature, it is resistant on sintering. Such re actor can be the alternative for generally applied converters containing the barium oxide. Experimental results of cat alytic converter containing various quantities of magnesium oxide for SI engi nes with lean mixtures are presented in t he paper. Researches involved both labor atory and engine tests. The laboratory researches concern the topogr aphy active surface of t he reactor with the scanning electron microscopy) method. Size of platinum and rhodium crystallites obtained from the Scherrer dependence analyzing the diffractive spectrum of the X-radiation (XRD) was about 5 nm. Moreover method covering of reactor's active layers on the metal- monolith is presented. Engine researches comprised CO, THC, and NOx conversion for two engi nes in conditions of lean (A/F=20.0), reach (A/F=14.0), and stoichiometric (A/F=14.7) mixtures. CO, THC, and NOx conversion were stated in the de pendence of temperature catalytic process in conditions of the various mixtures: