Fuel temperature influence on spray and combustion characteristics in a constant volume combustion chamber (CVCC) under simulated engine operating conditions
Fuel temperature influence on spray and combustion characteristics in a constant volume combustion chamber (CVCC) under simulated engine operating conditions
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DOI：
10.1016/j.fuel.2015.08.004
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发表时间：
2015-11
期刊：
影响因子：
7.4
通讯作者：
Joonsik Hwang;Youngsoo Park;C. Bae;Jin-wook Lee;Soon-Chan Pyo
中科院分区：
文献类型：
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作者：
Joonsik Hwang;Youngsoo Park;C. Bae;Jin-wook Lee;Soon-Chan Pyo
柴油机冷起动过程中存在着碳氢化合物排放量高和燃烧不稳定的问题。为了解决这些问题，必须了解燃油温度对喷雾和燃烧的影响。在这项研究中，宏观喷雾和燃烧实验进行了广泛的燃料温度范围从243至313 K。试验是在模拟低温冷起动条件下进行的。在定容燃烧室（CVCC）中结合了室内压力分析和高速成像。在模拟发动机操作条件下，以35 MPa的喷射压力将柴油燃料喷射到CVCC中。在宏观喷雾成像中，冷柴油的液体穿透长度较长，喷雾角较窄。燃油蒸发衰减和环境空气卷吸是造成喷雾特性恶化的主要原因。在燃烧成像中，检测到柴油机冷起动条件下喷雾的部分失火。另一方面，在热态启动条件下，所有的喷雾羽流都被成功点燃。冷燃料在点火延迟期内由于混合气制备不充分，导致燃烧室内压力峰值和火焰亮度峰值降低。
High amount of unburned hydrocarbon emission and combustion instability are serious problems in diesel engines during cold starting. In order to solve these troubles, the effects of fuel temperature on spray and combustion should be understood. In this study, macroscopic spray and combustion experiments were carried out over a wide range of fuel temperatures from 243 to 313 K. The tests were performed under simulated low temperature cold start condition. In-chamber pressure analysis and high speed imaging were combined in a constant-volume combustion chamber (CVCC). The diesel fuel was injected into the CVCC under simulated engine operating conditions with an injection pressure of 35 MPa. The cold diesel fuel showed a longer liquid penetration length and a narrower spray angle in macroscopic spray imaging. The reasons for the deteriorated spray characteristics were revealed to be the attenuation of the fuel evaporation and ambient air entrainment. In combustion imaging, partial misfires of the diesel spray were detected under cold start condition. On the other hand, all of spray plumes were successfully ignited under hot start condition. The peaks of in-chamber pressure and flame luminosity were decreased with cold fuel because of the poor air–fuel mixture preparation during the ignition delay period.