METHOD FOR DECREASING NITROGEN OXIDE IN INTERNAL COMBUSTION ENGINE AND EQUIPMENT THEREFOR

摘要

PURPOSE:To effectively reduce and purify nitrogen oxide irrespective of gaseous oxygen concentration in exhaust gas without ruining low fuel expenses of the engine in lean-burn engines, diesel engines, etc. CONSTITUTION:Gaseous hydrogen from a hydrogen generator 1 for generating hydrogen by electrolyzing water or steam using a conducting membrane (solid electrolyte) having a proton conducting function is supplied to the inlet side of a catalytic device 2 installed in an exhaust system Ex for catalytically reacting gaseous hydrogen with nitrogen oxide to decompose them into gaseous nitrogen and water in the presence of nitrogen oxide and gaseous oxygen in exhaust gas generated by the combustion of feed fuel in the combustion chamber of an internal engine E. Nitrogen oxide in exhaust gas is efficiently reduced by a direct reducing purification by gaseous hydrogen in the low temp. atmosphere of >=350 deg.C.