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为了提高开式燃烧室柴油机的性能,首要的是改善预制混合气的燃烧过程以及紧接其后的主混合气的形成。我们用辅助油束分别在燃烧室内不同的地方先产生一种预制混合气。本文就是研究这种预制混合气燃烧火焰的扩展对柴油机性能、尤其是输出功率、烟度和NO浓度的影响。研究结果综述如下: (1) 如果辅助油束安排在主油束易着火区(例如主油束的前峰和中段),虽烟度下降,但柴油机功率也下降。因此最好是把辅助油束喷到在主油束根部的地方。 (2) 采用一只喷油器实现二级喷油的方法难以有效地改善柴油机性能。这是因为第一级喷入的燃料落在随后喷入的主油束易着火区。为提高二级喷油的效果,第一级喷入的燃料所形成的预制混合气中含油应当更稀薄些。这可在压缩冲程初期喷入辅助燃料实现之。
In order to improve the performance of the open-hearth combustion engine, it is of prime importance to improve the combustion process of the pre-mixed gas and the formation of the main mixed gas immediately thereafter. We use an auxiliary oil bundle to produce a pre-mixture at different locations in the combustion chamber. This article is to investigate the effect of this prefired mixed-gas combustion flame on diesel engine performance, especially output power, smoke, and NO concentration. The results of the study are summarized as follows: (1) If the auxiliary fuel bundles are arranged in areas prone to ignition of main oil bundles (for example, in the front and middle sections of the main oil bunker), the diesel engine power is reduced although the smoke level is decreased. Therefore, it is best to spray the auxiliary oil to the root of the main oil. (2) It is difficult to effectively improve the performance of a diesel engine by adopting a single injector to realize two-stage injection. This is because the fuel injected in the first stage falls on the easy-to-fire area of the main oil jet that is subsequently injected. In order to improve the effect of secondary fuel injection, the fuel contained in the primary fuel should form leaner oil in the pre-mixture. This can be done by injecting auxiliary fuel early in the compression stroke.