The Effect of the Diesel Cetane Number on Exhaust Emissions Characteristics by Various Additives

Abstract

This paper described the effect of the diesel cetane number on exhaust emissions characteristics according to various additives. In addition, the emission characteristics of test fuels blended with three additives (GTL, biodiesel and additive for improving CN) were analyzed and the potential for uses of these additives were evaluated in this study. To achieve this purpose, the test diesel vehicle with a two-thousand cubic centimeter displacement was used to analyze the emission characteristics according to the CN. Also, the NEDC (New European Driving Cycle) was applied as the test mode which is widely used as the test method for environmental certification of diesel vehicles. To analyze the characteristics of HAPs, the VOCs and PAHs were analyzed from the BTEX and the particulate matter, respectively. The analysis results revealed that the CO emissions show the largest reduction rate while the NOx+THC emissions are reduced at a low as the CN got higher. In the NEDC mode, the PM emissions in the EUDC mode were found to be at a lower level than those in the UDC mode. As for the VOCs and PAHs characteristics, the VOCs of the CN 58 show the lowest amounts. Also, the PAHs of diesel blended with GTL show the highest level, followed by those of diesel blended with biodiesel and diesel blended with cetane additive.

The Effects of Neat Biodiesel and Biodiesel and HVO Blends in Diesel Fuel on Exhaust Emissions from a Light Duty Vehicle with a Diesel Engine

“…Additionally, it was observed that all aromatics have a higher PM formation tendency than paraffins . This may explain the PM reduction in the case of HVO blend, however, the opposite tendency was also obtained and was attributed to the improved cetane number in comparison to diesel fuel, resulting in a reduction of the premixed combustion region, while diffusion combustion increases . As shown by Happonen and co-workers even higher PM emissions reductions are possible by blending HVO fuel with a suitable oxygenate.…”

“…Moreover, pure HVO has a very high cetane number (>70) and its addition to diesel fuel increases the cetane number linearly. It was found that increased cetane number also reduced emissions of HC and CO, probably due to improvement of ignition performance …”

“…11 In turn, Lim et al indentified the increased cetane number with HVO addition to diesel fuel as an important factor for reducing the CO emission level. 30 During the EUDC phase, emissions of CO were at a very low level, due to the high effectiveness of the vehicle's diesel oxidation catalyst at removing CO, and comparable for all tested fuels. No reductions in CO emissions during the EUDC phase were observed for any of the fuels containing FAME, nor for HVO blend.…”

“…It was found that increased cetane number also reduced emissions of HC and CO, probably due to improvement of ignition performance. 30 Another cause for the observed reduction may be a decrease in concentration of precursors for carbonyl compound formation and the degree of molecular unsaturation. The ability of paraffinic fuel to reduce emission of carbonyl compounds was also found in some earlier studies.…”

Experimental investigation on performance, combustion, and emission characteristics of diesel doped with green synthesized nano cerium oxide

“…In this connection, extensive study is going on to improve the performance of diesel engine by doping diesel fuel with specific nanomaterials. Doping will not only enhance the thermal efficiency of engine bust also accounts for reduction of emissions from the combustion 8,9 . In recent years, many researchers have worked in this theme and reported the influence of various fuel additives such as metal oxide in nanoscale form.…”