【摘要】 为了研究涡轮增压缸内直喷汽油机(TGDI)匹配整车在NEDC循环时颗粒物排放特性,以一款1.5L TGDI发动机为研究对象,在发动机台架上运行车辆NEDC循环对应的发动机工况来测试初始PM(Particulate Matter)与PN(Particulate Number)。该发动机初始PM为10 mg/km,PN为12×1013。PM排放不满足欧五,PN排放不满足欧六B,PM与PN排放均不满足开发目标。通过燃油二次喷射,优化二次喷射点火角,优化启动阶段空燃比,优化三元催化器加热时间与油轨压力,最终使PM降为1 mg/km,PN降为2.5×1012,满足欧六B与开发目标。研究表明:汽油二次喷射可以降低50%的颗粒物排放;三元催化器加热时间由60 s增加至80 s,可以降低10%的PN排放;PN与PM随着轨压压力的升高,先降低后升高,轨压压力0.8 MPa为最优方案。更多还原

【Abstract】 In order to study the Particle Emission characteristics of NEDC cycle when vehicle matched TGDI engine, a 1.5 L TGDI engine is adopted to measure initial PM and PN by running engine operation point corresponding to the NEDC cycle of the vehicle on the engine test bench. The initial PM of the engine is 10 mg/km while PN is 12*1013, which means that PM emission does not meet the requirements of Euro V and PN emission does not meet the requirement of Euro VI B, therefore both PM and PN emissions don’t reach the development target. By using Secondary Fuel Injection, optimizing Secondary Injection Timing, optimizing Lambda of Engine Start Phase and optimizing TWC warming time and rail pressure,PM and PN emissions are reduced to 1 mg/km and 2.5*1012 respectively meeting the development target of Euro VI B. The study states that the secondary injection of gasoline can reduce particle emissions by 50%;a 10% reduction of PN emission can be realized by increasing TWC warming time from 60 s to 80 s, PM and PN emissions are firstly reduced and then increased with the increasing rail pressure turning out that8 bars is the optimal rail pressure.更多还原