Effects of spray impingement, injection parameters, and EGR on the combustion and emission characteristics of a PCCI diesel engine
Effects of spray impingement, injection parameters, and EGR on the combustion and emission characteristics of a PCCI diesel engine
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DOI：
10.1016/j.applthermaleng.2011.11.011
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发表时间：
2012-05-01
影响因子：
6.4
通讯作者：
Yokobe, Sumito
中科院分区：
文献类型：
--
作者：
Kiplimo, Robert;Tomita, Eiji;Yokobe, Sumito
在一台单缸试验机和一台光学可达发动机上研究了喷雾碰壁、喷射参数和废气再循环（EGR）对预混压燃（PCCI）柴油机燃烧特性和排放的影响。试验是在恒转速、可变喷射压力和EGR率条件下进行的。在所有实验条件下测量排气排放和缸内压力。基于柴油喷雾演变和燃烧过程可视化以及性能和废气排放进行了分析。较高的喷射压力导致较低的烟雾，碳氢化合物（HC）和氮氧化物（NOx）的排放量，但大致相同的CO排放量相比，较低的喷射压力。较高的EGR率导致同时减少氮氧化物和烟尘排放，由于较低的燃烧温度相比，传统的柴油燃烧。然而，HC和CO的排放量增加，由于燃料的冲击，散装淬火，和过度混合，导致空气燃料混合物是太稀燃烧。确定了一个最佳的喷雾目标点，导致更低的碳烟，CO和HC的排放量，但更高的NOx排放量没有EGR。同时减少NOx和碳烟的最佳喷雾靶点，通过引入EGR，这是伴随着均匀燃烧和低亮度火焰归因于燃料撞击在活塞碗壁。(C)2011爱思唯尔有限公司保留所有权利。
The effects of spray impingement, injection parameters, and exhaust gas recirculation (EGR) on the combustion characteristics and exhaust emissions of a premixed charge compression ignition (PCCI) diesel engine were investigated using a single-cylinder test engine and an optically accessible engine. Tests were carried out under constant speed with variable injection pressures and EGR rates. Exhaust emissions and in-cylinder pressures were measured under all experimental conditions. Analyses were conducted based on diesel spray evolution and combustion process visualisation coupled with performance and exhaust emissions. Higher injection pressures led to lower smoke, hydrocarbons (HC), and nitrogen oxide (NOx) emissions but had roughly the same CO emissions compared with lower injection pressures. Higher EGR rates led to the simultaneous reduction in NOx and soot emissions due to lower combustion temperatures compared to conventional diesel combustion. However, HC and CO emissions increased due to fuel impingement, bulk quenching, and over-mixing, leading to an air fuel mixture that was too lean to burn. An optimum spray targeting spot was identified, leading to lower emissions of soot, CO, and HC but higher NOx emissions without EGR. The simultaneous reduction in NOx and soot was achieved using the optimum spray targeting spot by introducing EGR, which was accompanied by homogenous combustion and a low luminosity flame attributed to fuel impingement on the piston bowl wall. (C) 2011 Elsevier Ltd. All rights reserved.