中文摘要：

利用流体分析软件Fire建立了柴油机氧化催化器（DOC）的三维仿真模型，并通过试验验证了模型的有效性。通过仿真模型分析了空速、DOC入口温度、NO与NOx浓度比（RNO）、CO浓度和HC浓度对柴油机DOC后NO2与NOx浓度比（RNO2）的影响。仿真结果表明：增加空速，DOC后的RNO2降低；DOC入口的RNO、CO浓度、HC浓度增大，DOC末端的RNO2增加；DOC后的RNO2随DOC入口排气温度的增加先升高后降低，在600K附近达到最大值。

英文摘要：

A DOC 3D model for diesel engine was established with FIRE fluid software and its validity was verified by the ex- periment. Based on the model, the influences of space velocity, DOC inlet temperature, NO/NOx ratio （RNO）, CO concentra- tion and HC concentration on NO2/NO. ratio （RNO2） after DOC were analyzed. The results show that RNO2 decreases after in- creasing the space velocity. With the increase of RNO, CO concentration and HC concentration at the entrance of DOC, the RNO2 after DOC increases. With the increase of DOC entrance temperature, the RNO2 after DOC first increases and then decreases, and reaches the maximum at 600 K.