The conventional threeway catalysts are not efficient enough to remove the CO and hydrocarbons during vehicle coldstart period due to the low temperature of catalyst bed.

汽车冷启动时催化剂床层温度低，尾气中的CO和烃类不能被传统三效催化剂有效消除。

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In a testing of petrolic engine, about 70% to 80% of nonmethane hydrocarbon is emitted into atmosphere without catalysis conversion in theoment of coldstart, so that serious pollution is produced.

在汽油机的一个测试循环中，约占排放污染物总量70%～80%的非甲烷碳氢化合物是在汽油机冷起动阶段没有经催化转化而直接排入大气中，造成严重污染。

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