高效型SCR尿素计量泵精度标定台方案设计

Design of Efficiency Calibration Platform for Measurement Accuracy of SCR Urea Pump

SCR技术已成为柴油车降低NOX排放的主流技术方法。尿素泵作为SCR系统的核心部件之一,其计量精度直接影响系统运行效率。针对传统的尿素泵标定方法的不足,提出一种基于微小椭圆齿轮流量计的尿素计量泵精度标定台,设计了气助型和非气助型尿素泵标定方案,对于无回流型尿素计量泵,可采用单流量计装在吸液管上直接测量。对于有脉动强且有回流的尿素计量泵,使用“减重”法测量,在吸液管与回液管各安装一个椭圆齿轮流量计,通过差值的办法得到尿素喷射量。经过实践,实时性强,精度高。

SCR technology has become the mainstream technology to reduce NOX emissions from diesel vehicles.As one of the most important components of the SCR system,the measurement accuracy of urea pump has a direct impact on the efficiency of the system.In view of the deficiency of traditional calibration method of urea pump,a precision calibration platform for urea metering pump based on micro-elliptical gear flowmeter is proposed.The calibration schemes of air-assisted and non-air-assisted urea pumps are designed.For the urea pump with strong pulsation and reflux,the“Weight loss”method is used.An elliptical gear flowmeter is installed in the suction pipe and the return pipe respectively,and the urea injection quantity is obtained by the difference value.Through practice,the calibration platform has strong real-time performance and high precision.