用于SCR催化器性能评价的尿素喷射控制系统

A Urea Injection Control System for the SCR Catalyst Performance Evaluation

基于16位微控制器控制单元和后台管理系统,开发用于选择性催化还原(selective catalytic reduction,SCR)催化器性能评价试验的尿素喷射控制系统。根据上位机给定的目标,采用双闭环控制方式控制喷射压力,基于尿素喷射速率与尿素喷射系统驱动占空比脉谱图的开环控制方式控制喷射速率。利用柴油机后处理系统性能评价试验装置的废气流量与温度控制子系统来保障工况条件;由排放测量设备测量NOx排放和氨泄漏;根据标定试验确定控制特性;通过台架试验验证尿素喷射控制系统可用性。结果表明,尿素喷射控制系统完全能够满足SCR催化器单体和组合评价测试的要求。

Based on a 16-bit microcontroller control unit and a back-end management system, a urea injection control system for selective catalytic reduction(SCR) catalyst performance evaluation tests is developed. According to the target value given by the upper computer, the double-closed-loop control mode is used to control the injection pressure, and the open-loop control mode based on duty cycle pulse spectrum of urea injection rate and urea injection system is used to control the injection rate. The exhaust gas flow and temperature control subsystem of the diesel engine after-treatment system performance evaluation test device is used to ensure the working conditions. The NO_x concentration and ammonia leakage are measured by using an emission measurement device. The control characteristics are determined by the calibration tests. Availability of the urea injection control system is verified by bench test. The results show that this urea injection control system can fully meet the requirements of SCR catalyst monomer and combination evaluation test.