通用型 SCR 还原剂喷射系统的设计与控制策略研究

摘要

自主设计了通用型SCR还原剂喷射系统，并在试验的基础上以CA6DL2-35E3高压共轨、增压中冷柴油机为基础样机，对其自学习控制策略与算法进行了研究，对通用型SCR系统的结构框架和尿素自动供给装置的工作过程进行了详细介绍。通过发动机台架试验制取了原机NOx 排放脉谱、SCR后处理器转化效率脉谱、氨氮比脉谱以及尿素喷射量脉谱，且通过自学习控制策略制取了还原剂喷射量脉谱。利用CodeWarrior软件平台对其自学习控制策略和算法完成了C程序的编写。最后通过发动机台架试验对自行设计的SCR还原剂喷射系统和自学习控制策略与算法进行了试验验证。试验数据表明，该喷射系统可以确保尿素及时供给和喷嘴入口处压力恒定，自学习控制策略和算法可以实现通用型SCR系统的功能，且能够满足我国国Ⅳ排放法规要求。%The universal SCR injection system was self-designed and its self-learning control strategy and algorithm were re-searched based on CA6DL2-35E3 diesel engine with high-pressure common rail and turbocharged intercooling .The structure of SCR system and the working process of urea auto-supplied device were introduced in detail .The MAPs of NOx emission ,SCR conversion efficiency ,ammonia-nitrogen ratio and urea injection quantity were acquired by the experiment and the MAP of re-ductant injection quantity was determined by self-learning control strategy .The self-learning control strategy and algorithm were compiled into C codes with the software of CodeWarrior .Finally ,the self-designed system and control algorithm were verified by bench test .The results show that the injection system can supply urea in time and keep pressure constant in the in-let .The self-learning control strategy and algorithm can realize the function of universal SCR system and meet the state-Ⅳ e-mission legislation .