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为了改善8V120柴油机的性能,对它的进气道进行研究与改进是重要的措施之一。该机系采用切向进气道。在该气道及 T—148进气道试验分析的基础上进行了气道的改进设计,并且定型了两种新的切向气道。这两种改进气道的共同特点是降低了气道阻力,而它们的主要区别在于涡流比不相同。这主要是为了以后在单缸试验机上进一步研究涡流比对发动机工作性能的影响及其与燃烧室、燃料系统等的配合问题。试验过程中初步摸清了影响切向气道性能的一些敏感部位及切向气道设计中应注意的问题。对于如何评价发动机的涡流比进行了初步的探讨。通过切向气道的改进设计发现它在解决阻力与涡流这一矛盾上并不理想。这种气道由于不能使气门流通面积得到充分的利用,因此使得气道的阻力较大。这是该种气道的主要缺点,也是同类型柴油机大多采用螺旋气道的原因之一。因此建议在气道改进工作取得一定的台架效果之后,对该机的气缸盖进行彻底的改进设计。
In order to improve the performance of the 8V120 diesel engine, it is one of the important measures to study and improve its intake port. The machine uses tangential inlet. Based on the experimental analysis of the airway and the T-148 air intake, the airway improvement design was performed and two new tangential airways were finalized. The common feature of these two improved airways is reduced airway resistance, and their main difference is that they have different eddy currents. This is mainly to further study the influence of the eddy current ratio on the working performance of the engine and its cooperation with the combustion chamber and the fuel system in a single cylinder testing machine later. During the experiment, some sensitive sites that affect the performance of the tangential airway and the problems that should be paid attention to in the design of the tangential airway were found. How to evaluate the engine's eddy current ratio for a preliminary discussion. The improved design of the tangential airway shows that it is not ideal for solving the contradiction between resistance and eddy current. This airway can not make full use of the valve flow area, thus making the airway resistance larger. This is the main drawback of this airway, but also one of the reasons why most diesel engines of the same type adopt spiral airways. Therefore, it is suggested that a thorough improvement design of the cylinder head of the aircraft should be made after a certain gantry effect is obtained in the airway improvement work.