The major objective of the presented work is to explore the effect of post injection (PI) strategy using neat diesel fuel (D100) blended with cetane number enhancer (CNE). The motive behind adding CNE in diesel fuel was to lower its self-ignition temperature and hence delay period subsequently. This can lead to more efficient combustion of post injected fuel which leads to lower incomplete combustion losses. The CNE used was Di-Tert-Butyl Peroxide (DTBP) which was blended with D100 in proportion of 1 % by volume. Initially experiments were conducted with D100 under various PI modes where variation of post injection timing (PIT) as well as post quantity (PQ) was considered. The experimental results showed that implementing PI resulted in lower smoke, unburned hydrocarbon (UHC), carbon monoxide (CO) and nitrogen oxides (NOx) emissions compared to single injection while affecting fuel consumption negatively. Then after similar experiments under various PI modes were repeated using blends of D100 and DTBP (D/DTBP) and results were compared with D100 case. It was found that addition of CNE in D100 resulted in more complete combustion of post fuel which further reduced CO and UHC emissions. The shorter delay period in case of D/DTBP blend compared to D100 case led to lower NOx emissions as well as higher smoke emissions. The obtained results revealed that PI mode with 3 mg PQ and 20° after top dead center (ATDC) PIT with D/DTBP blend offered 41.18 %, 17.55 %, 64 % and 62.5 % reduction in smoke, NOx, UHC and CO emissions respectively compared to single injection mode using D100 fuel.

中文翻译：

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柴油发动机中高十六烷值柴油燃料和后喷射模式的组合：降低废气排放的途径


本工作的主要目的是探索使用纯柴油 （D100） 与十六烷值增强剂 （CNE） 混合的后注射 （PI） 策略的效果。在柴油中添加 CNE 的动机是降低其自燃温度，从而延迟随后的周期。这可以更有效地燃烧后喷射燃料，从而降低不完全燃烧损失。使用的 CNE 是过氧化二叔丁酯 （DTBP），它与 D100 按体积 1% 的比例混合。最初，在各种 PI 模式下使用 D100 进行实验，其中考虑了注射后时间 （PIT） 和后数量 （PQ） 的变化。实验结果表明，与单次喷射相比，实施 PI 可降低烟雾、未燃烧的碳氢化合物 （UHC）、一氧化碳 （CO） 和氮氧化物 （NOx） 排放，同时对燃料消耗产生负面影响。然后，在各种 PI 模式下使用 D100 和 DTBP （D/DTBP） 的混合物重复进行类似实验，并将结果与 D100 案例进行比较。研究发现，在 D100 中添加 CNE 会导致后燃料更完全燃烧，从而进一步减少 CO 和 UHC 排放。与 D100 案例相比，D/DTBP 混合物的延迟时间更短，从而降低了 NOx 排放量和较高的烟雾排放量。获得的结果表明，与使用 D100 燃料的单次喷射模式相比，具有 3 mg PQ 和 20° 后上止点 （ATDC） PIT 的 PI 模式分别减少了 41.18 %、17.55 %、64 % 和 62.5% 的烟雾、NOx、UHC 和 CO 排放。