缸盖排气道结构优化对柴油机性能的影响

李丽丽，赵鹏，贾锡臣

潍柴动力股份有限公司发动机研究院，山东 潍坊  261061

摘要：为增大柴油机缸盖排气道的流量因数、提高柴油机性能，优化某6缸柴油机缸盖排气道结构，试验研究缸盖排气道优化前、后排气流量因数和柴油机性能。试验结果表明：优化后的缸盖排气道平均流量因数提高6.7%；缸盖排气道优化前、后，柴油机进、排气平均压力脉冲均随转矩和转速的增加而增大；缸盖排气道优化后柴油机的平均进气压力大于原缸盖排气道，平均排气压力小于原缸盖排气道；装配优化后缸盖排气道的柴油机燃烧持续期缩短且燃烧中心更接近上止点，NO_x排放降低11%~17%，燃油消耗率降低约1 g/(kW·h)。优化后的缸盖排气道有助于改善柴油机充气效率，提高工质的燃烧质量，降低油耗。

关键词：排气压力；泵气损失；进气流量；缸盖排气道；结构优化

Effect of the cylinder head exhaust duct structure optimization on diesel engine performance

LI Lili, ZHAO Peng, JIA Xichen

Engine Research Institute, Weichai Power Co.,Ltd., Weifang 261061, China

Abstract：In order to enlarge the exhaust flow coefficient of cylinder head exhaust duct and improve diesel engine performance, a 6-cylinder diesel engine is selected as an example, the structure of cylinder head exhaust channel is optimized, and the engine performance before and after the optimization is studied experimentally. The results show that the average flow coefficient of the cylinder head exhaust duct increases by 6.7% after optimization. The mean value of inlet and exhaust pressure pulse both with original and new cylinder head exhaust duct of diesel engine increases with the increase of torque and speed. The average value of intake pressure of the new cylinder head exhaust duct is larger than that of the original one, and the average value of exhaust pressure is smaller. The combustion duration of the new cylinder head exhaust duct is shortened and its combustion center is closer to the top dead center. NO_xemissions are reduced by 11% to 17%, and fuel consumption is reduced by about 1 g/(kW·h). New cylinder head exhaust duct is more helpful to improve the diesel engine charging efficiency, improve the combustion quality of the working fluid, and then reduce fuel consumption.

Keywords:exhaust pressure;pumping loss;air intake flow;cylinder head exhaust duct;structural optimization