分级净化 meaning in English

stage purification

( 9 ) by studying matching between catalytic converter and exhaust gas system , the conclusions having been gotten as follow : " purifying step by step and driving step by step " and " mental substrate and chinaware substrate being used in same engine " being the laying principles in exhaust gas system , which can solve the contradiction between high converting efficiency of exhaust emission and small loss of power , fuel economics , the rapid light - off and laying difficulty of catalyst
（ 9 ）进行了催化转化器与排气系统的匹配研究，对于催化剂的布置，提出了“分级净化，逐级推动”的原则；对于载体形式的选择，提出了“金属载体和陶瓷载体复合”使用的原则。这样可以良好的解诀催化转化器与发动机匹配时，排气污染物高净化率与动力性经济性损失小之间的矛盾、快速起燃和结构布置困难的矛盾。