Urea-SCR催化器压力损失及其对柴油机性能的影响

在柴油机排气系统上安装SCR催化器会有效降低NOx排放，但同时也会造成较大的排气背压，对发动机的动力性和经济性带来负面影响。该文利用计算流体力学软件FIRE和发动机热力循环软件BOOST相耦合的方法，对SCR催化器的压力损失进行了计算，对带Urea-SCR催化器的柴油机动力性和经济性能进行了仿真分析。结果表明，催化器载体的沿程阻力损失是催化器压力损失的主要来源；柴油机排气系统上安装SCR催化器后，其动力性、经济性均有所下降，下降幅度在5%左右。研究结果对SCR催化器的设计和安装有一定指导意义。

Pressure loss of urea-SCR converter and its influence on diesel engine performance

Urea-SCR catalytic converter can effectively reduce the NOx emission of diesel engines, but meanwhile catalytic converter will cause some pressure loss in the exhaust system, which has negative influences on the engine performances. With the aid of BOOST (engine cycle simulation software) coupled with FIRE (computational fluid dynamic software), the pressure loss caused by converter was calculated and a modeling simulation and validity test were conducted on the power performance and fuel economy of diesel engine with urea-SCR catalyst. The results show that the pressure losses mainly come from the monolith resistance along the converter. The exhaust back pressure rising caused by SCR catalyst has some influence on the diesel fuel economy and power performance, which are reduced by about 5%. The results can provide a reference for optimum design of SCR catalytic converters and assembling.