柴油机稀燃NOx催化剂的性能评价试验

如何在稀燃条件下降低柴油机尾气中的NOχ是柴油机后处理技术的难点之一。在发动机台架上对乙醇作为还原添加剂的柴油机稀燃NOχ催化剂进行了起燃特性和空速特性的性能评价，并考察了该催化剂对欧Ⅲ排放法规的适应性。结果表明：催化剂的起燃特性曲线先随温度升高而增加，后随温度升高而降低，并且整个转化率曲线随空速增加而下降；欧Ⅲ测试循环中，NOχ排放值明显降低，其转化效率达50％以上，能够满足欧Ⅲ要求．但CO和HC排放值明显升高，不能满足欧Ⅲ要求，需要采取其他措施。

Performance Evaluation of the Lean NOx Catalyst for Diesel Engine

s: Reducing the exhaust NO_x in the lean combustion is one of the difficult points in exhaust after-treatment of diesel engine. In this paper, the light-off and space velocity characteristics of lean NO_x diesel catalyst with ethanol as the additive were evaluated on engine test bench and the adaptability of this catalyst to the Euro III Standard (ESC) was also tested. The test results show that the light-off curve of the catalyst at low temperature range increases with the increase in the catalyst inlet temperature while at high temperature range it decreases with the increase in the temperature. The whole curve will decrease with the increase in space velocity. The exhaust NO_x emission is reduced greatly by using this diesel catalyst with the conversion efficiency over than 50%, which can meet the requirement of Euro III, however, exhaust CO and HC increases greatly and other measures should be taken to make them meet Euro III standard.