DEF DOSING USING MULTIPLE DOSING LOCATIONS WHILE MAINTAINING HIGH PASSIVE SOOT OXIDATION

Diesel exhaust fluid is metered into an engine exhaust gas aftertreatment system having a close coupled SCR catalyst and a main SCR catalyst. The DEF is injected into two injector locations, one upstream of the close coupled SCR catalyst and another upstream of the main SCR catalyst, the quantity of DEF in each injector being based on primarily the temperature at the main SCR catalyst and the massflow of the NOx through the aftertreatment system. This method of injection enables a relatively better fuel economy outcome while meeting the regulated tailpipe NOx emission levels and the N2O formation limits. 将柴油机排气流体计量加入内燃机废气后处理系统，该系统具有紧密连接的SCR催化剂和主SCR催化剂。将DEF喷射至两个喷射器位置，一个位于紧密连接的SCR催化剂的上游，另一个位于主SCR催化剂的上游，每个喷射器中的DEF量主要基于主SCR催化剂的温度和通过后处理系统的NO质量流量。该喷射方法能够在满足规定的NO尾气排放水平和NO形成限制的同时实现相对更好的燃料经济性结果。