燃料着火性对增压中冷柴油机瞬态工况排放的影响

Effects of fuel cetane number on emissions from a turbocharged and intercooled diesel engine under transient operating conditions

应用自行开发的瞬态工况控制系统及排气采集装置,试验研究了不同着火性的燃料对车用增压中冷柴油机瞬态工况下排放特性的影响。研究结果表明,适当提高燃料十六烷值可有效降低HC和NOx排放。在稳态工况下,十六烷值由40增加到66时,在1800 r/min低负荷工况下HC排放降低62%;对于CO排放及消光烟度,十六烷值存在一个最佳值。瞬态工况排放与稳态工况存在明显差异,在恒转速增负荷工况下,随着负荷的增加,HC和CO排放及烟度迅速上升,然后降低趋于一稳定值,且随着瞬变率的增大,CO排放和消光烟度峰值上升;增加燃料十六烷值,可明显降低中等转速增负荷工况下的CO和HC排放及消光烟度;在高速增负荷工况下,十六烷值为66和55,燃料的排气烟度基本相近。

The effect of fuel cetane number on the emission behavior from turbocharged and intercooled diesel engine were investigated under steady and transient operating conditions with a self-made special transient operation control and exhaust measurement system. The high cetane number fuel can improve HC and NOx emissions. Under 1800 r/min, low load operating conditions, when the fuel cetane number increases from 40 to 66, HC decreases by 62%. To improve the CO and opacity smoke emissions, the fuel cetane number exists an optimum. The emission behavior from diesel engine under constant speed increasing torque transient operating conditions are different with that under steady operating conditions, and with the increase of engine torque changing rate HC, CO and opacity smoke emissions all rise. The high cetane number fuel can improve CO, HC and opacity smoke emissions under middle-speed operating conditions. Under the high speed increasing torque operating conditions, the two fuel cetane numbers 66 and 55 have no difference on opacity smoke emission.