A two-mode late intake valve closing system was designed for diesel engine to adjust the intake valve close timing based on the camshaft. The system was adjusted and assembled on a six-cylinder diesel engine. Tests were conducted at loads up to 1.0 MPa BMEP to study the effects of intake valve closing actuation system on combustion in diesel engine. Results show this system decreases the pressure and temperature during the compression stroke, resulting in an increased ignition delay as fuel fully mixed. Pre-mixed combustion is enhanced. The system can significantly reduce the trade-off emissions between NOx and soot, with fuel efficiency improvements of 3.5% and 7% at 1 600 r/min, 50% load and 1 900 r/min, 50% load respectively.%设计了一种基于凸轮轴的柴油机两模式进气门晚关系统,利用两种典型的气门升程曲线来调整气门定时,经过精细调整后装配于一台直列6缸排量为12L的柴油机上,在1.0 MPa的平均有效压力(BMEP)下研究了进气门晚关对于重型柴油机燃烧的影响.结果表明,该系统降低了压缩过程的压力和温度,使滞燃期延长,着火前油气混合更均匀,预混燃烧比例增加.试验证明,该系统可以使不同工况的碳烟和NOx折衷排放降低,有效热效率在1600 r/min、50％负荷和1900 r/min、50％负荷时分别有3.5％和7％的提高.
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