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研究旨在评佑不同的发动机扭矩和转速工况下引燃喷射对涡轮增压直喷(TDD)柴油机燃烧的影响。本研究中,在宽广范围内变动了引燃喷射定时和持续期,并分析了它们对燃烧压力、放热率、引燃及主燃烧延迟、燃烧过程以及NO_X,和烟度排放等方面的影响。对一台直列4缸、涡轮增压、共轨喷油系统的FIAT 1. 931. TDI柴油机进行了试验。为了获得燃烧压力,在燃烧室内安装了一个压电传感器,从这些信号中推导出总放热率,以分析燃烧特性。利用排气分析仪测量了污染物排放量,采用暗度计测量烟度。研究发现,引燃喷射定时和持续期对其自燃倾向有显著影响,特别是引燃喷射的自燃主要发生在低的定时值和高持续期时。而且,引燃喷射定时对引燃喷射滞燃期的影响比引燃持续期更明显,然而,这两个变量对主燃烧滞燃期的影响取决于发动机的运行工况。引燃喷射参数对发动机排放特性的影响也很显著,特别是NO_X,的排放水平主要受到引燃持续期的影响,然而在发动机较低负荷和转速时,引燃喷射定时的影响更为明显。碳烟排放似乎受到这两个参数变化的影响.但它们的影响龙中高合蒜时特别显著.
The purpose of the study was to evaluate the effects of pilot injection at different engine torques and speed conditions on the combustion of turbocharged direct injection (TDD) diesel engines. In this study, the timing and duration of pilot injection were varied over a broad range and their effects on combustion pressure, heat release rates, pilot and main combustion delays, combustion processes, and NO x, and smoke emissions were analyzed . A test on a FIAT 1. 931. TDI diesel engine with an inline 4-cylinder, turbocharged, common rail fuel injection system was conducted. In order to obtain the combustion pressure, a piezoelectric sensor is installed in the combustion chamber, and the total heat release rate is derived from these signals to analyze the combustion characteristics. Exhaust analyzer was used to measure the amount of pollutant emissions and darkness was used to measure the smoke level. It is found that the timing and duration of pilot injection have a significant effect on the spontaneous combustion tendency. In particular, the pilot injection spontaneous combustion occurs mainly at low timing and high duration. Moreover, the timing of the pilot injection has a more significant effect on the ignition delay than the ignition duration. However, the effect of these two variables on the ignition delay of the main combustion depends on the operating conditions of the engine. The influence of pilot injection parameters on engine emission characteristics is also significant. In particular, the emission level of NO_X is mainly affected by the ignition duration. However, the influence of pilot injection timing is more obvious at lower engine load and speed. Soot emissions appear to be affected by these two parameter changes, but their effects are particularly significant when it is mixed with garlic.