三元(三效)催化净化器是指对汽车尾气中的CO、HC和NOX同时具有净化作用的催化转化装置。目前,国外主要以铂、钯、铑等贵金属为催化剂,国内正在研制以稀土加少量贵金属为催化剂的三元催化净化器。三元催化净化器外形设计一般为椭圆形,也有圆柱形或其它柱体形状。它主要由金属封 The three-way (three-way) catalytic converter refers to a catalytic converter that simultaneously purifies CO, HC, and NOX in automobile exhaust. At present, foreign countries mainly use platinum, palladium, rhodium and other precious metals as catalysts, and China is developing a three-way catalytic converter using a rare earth and a small amount of precious metals as catalysts. The three-way catalytic converter is generally oval in shape and has a cylindrical or other cylindrical shape. It is mainly made of metal seals