殷海红1，解永辉1，李海庆1，周海磊2,3，肖有强2,3
1.潍坊职业学院机电工程学院，山东潍坊261001；2.内燃机可靠性国家重点实验室，山东潍坊261061；3.潍柴动力股份有限公司，山东潍坊261061
摘要：针对某2级增压车用柴油机的废气再循环(exhaust gas recirculation，EGR)系统，试验研究不同EGR率对发动机经济性和排放性的影响，以及利用EGR实现进气旁通后对发动机性能的影响。试验结果表明：随着EGR率升高，柴油机燃油消耗率和噪声降低；排气温度升高，有助于提高选择性催化还原后处理效率；降低缸内压力，可以提高发动机可靠性。随着EGR率升高，NOx和HC排放明显减低，但会导致CO和烟度排放升高；EGR率低于23%时，CO和烟度排放升高缓慢，EGR率高于23%时，CO和烟度排放升高趋势明显。超低排放发动机应选择高EGR系统，当中冷后进气压力比涡前排气压力高时，EGR阀可作为旁通阀，将进气旁通到增压器涡端，提高增压器的效率和发动机缸内进气量，增加低速时的过量空气系数和低速扭矩。
关键词：柴油机；EGR系统；试验研究
Abstract: In this paper, the application of exhaust gas recirculation (EGR) in a twostage turbocharged automotive vehicle diesel engine is studied by experiment, the effects of different EGR rates on engine economy and emission, as well as the effects of EGR on engine performance after engine bypass are evaluated. The test results show that with the increase of EGR rate, the fuel consumption and noise of diesel engine decrease. The increase of exhaust temperature is benefit to SCR. Reduced pressure in cylinder can improve engine reliability. At the same time, with the increase of EGR rate, the NOx and HC of diesel decreased significantly, but the CO and smoke increased. When the EGR rate is lower than 23%, the increase is slow, while when the EGR rate is higher than 23%, the increase trend is obvious. For ultralow emission engines, high EGR systems are preferred. After engine bypass can improve the efficiency of the supercharger to improve the air intake in the engine cylinder, and then improve the excess air coefficient at low speed, and improve the low speed torque.
Keywords:diesel engine; EGR system; experimental study
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