气门重叠角的大小及位置对汽油机性能影响的研究

Study in Influence of Valve Overlap Angle on Engine Performance

改变配气相位是发动机提升性能和改善排放的重要途径之一,随着可变气门正时(VVT)技术的发展,使得气门重叠角的大小和位置都可调节,实现了根据不同发动机工况对配气相位进行调节,本文采用GT-power软件,针对发动机不同工况采用不同重叠角的大小及位置进行模拟研究,从性能角度给出不同重叠角大小及位置对性能的影响规律。研究表明:在扫气区,增加重叠角有利于提高充气效率同时抑制爆震,但重叠角位置不能过于靠后,在小负荷,采用大的重叠角会增加残余废气量,使得燃烧不稳定,然而通过前移重叠角位置可以使得在较大重叠角下仍然具有很好的残余废气控制。

The change of valve timing is one of the important ways to enhance the engine performance and Improve emissions. With the development of VVT technology and strict regulation, the size and position of valve overlap angle can be adjusted, and the valve timing is also adjusted according to different engine operating conditions. In this paper, the GT-power software is used to simulate and study the size and position of overlap angles in different engine conditions. The influence of different overlapping angle size and position on performance is analyzed according to engine performance. The results show that the increase of overlap angle is helpful to improve the VE and to suppress the knock in the sweep gas province, but the overlap angle can not be too late. In low load, large overlap angle will increase the amount of residual gases, which made the combustion instability. However the position of overlap angle forward can make a very good control of residual gas in a large overlap angle