This thesis identifies and assesses strategies for achieving Low Soot Combustion (LSC) in automotive diesel applications. The interaction of fundamental parameters such as fuel chemistry, mixture formation and temperature-control was investigated and the implications thereof on LSC were explored. For the purpose of this work, LSC is defined to have an emissions index for particulate matter (EI-PM) of equal or less than 0.4 g/kg of fuel and an emission index of oxides of nitrogen (EI-NOx) of equal or less than 1 g/kg of fuel.; Several distinct strategies were investigated using a single-cylinder engine including retarded LSC, premixed LSC and fuel with different chemical properties to identify the most promising approach to achieve LSC for diesel engines. A premixed strategy with diesel fuel was identified as a promising approach to achieve LSC for passenger car applications. Subsequently, this concept was refined and implemented into a 1.7L, 4-cylinder, production type diesel engine. A combination of narrow spray cone angles along with injection of a substantial amount of fuel at very advanced injection timings and EGR rates of more than 50% created combustion patterns that no longer followed the traditional soot/NOx trade off, and NOx and PM emissions could be reduced simultaneously. Consequently, the developed combustion strategy established predominantly premixed diesel combustion and exhibited reductions in NOx emissions of 82% and in PM emissions of 39% with a 4.5% penalty in net thermal efficiency compared to the base engine configuration.
展开▼
机译：本文确定并评估了在汽车柴油应用中实现低烟尘燃烧（LSC）的策略。研究了诸如燃料化学，混合物形成和温度控制等基本参数的相互作用，并探讨了其对LSC的影响。出于这项工作的目的，LSC被定义为具有等于或小于0.4 g / kg燃料的颗粒物排放指数（EI-PM）和等于或小于0.4 g / kg的氮氧化物排放指数（EI-NOx）。少于1克/千克燃料。使用单缸发动机研究了几种不同的策略，包括延迟LSC，预混合LSC和具有不同化学性质的燃料，以确定实现柴油发动机LSC的最有前途的方法。柴油的预混合策略被确定为实现轿车应用LSC的有前途的方法。随后，对该概念进行了改进，并应用于1.7升4缸生产型柴油发动机。狭窄的喷雾锥角加上在非常先进的喷射正时喷射大量燃料以及EGR率超过50％的组合所产生的燃烧模式不再遵循传统的烟灰/ NOx权衡，NOx和PM排放可能同时减少。因此，已开发的燃烧策略主要建立了预混合柴油燃烧，与基本发动机配置相比，NOx排放减少了82％，PM排放减少了39％，净热效率降低了4.5％。
展开▼
