基于文丘里管测量的EGR闭环控制试验研究

Experimental Study on EGR Closed-loop Control Based on Venturi Measurement

EGR技术是满足国六排放的关键技术之一,通过控制EGR率实现控制NOx排放,新鲜进气量和废气量精确测量是柴油机EGR闭环控制的前提。采用文丘里管测量EGR质量流量进行闭环控制研究,分别在发动机台架和整车PEMS进行稳态和瞬态工况验证。结果表明:文丘里管布置在EGR阀下游(EGR阀前置),在稳态工况下,测量偏差在1%以内;在瞬态工况下,大部分工况的偏差都在3%以内,能够满足国六整车匹配适应性和排放一致性控制要求。

Exhaust gas recirculation(EGR)is one of the key technologies to meet the emission of CN VI,NOx emission is controlled by controlling EGR rate,the accurate mass flow measurement of fresh air intake or exhaust gas is the key to diesel engine EGR valve closed-loop control.Venturi tube is used to measure the EGR mass flow for closed-loop control.The method was testified in the engine rig and PEMS under both steady and transient conditions.The results show that the Venturi tube is arranged downstream of the EGR valve(the front of the EGR valve),the measurement deviation rate is within 1%under steady conditions,and the measurement deviation rate of most working conditions is within 3%under transient conditions.The test results meet the requirements of CN VI emission consistency control and vehicle matching adaptability.