Reductions in Particulate and NO_x Emissions by Diesel Engine Parameter Adjustments with HVO Fuel

Abstract

Hydrotreated vegetable oil (HVO) diesel fuel is a promising biofuel candidate that can complement or substitute traditional diesel fuel in engines. It has been already reported that by changing the fuel from conventional EN590 diesel to HVO decreases exhaust emissions. However, as the fuels have certain chemical and physical differences, it is clear that the full advantage of HVO cannot be realized unless the engine is optimized for the new fuel. In this article, we studied how much exhaust emissions can be reduced by adjusting engine parameters for HVO. The results indicate that, with all the studied loads (50%, 75%, and 100%), particulate mass and NO(x) can both be reduced over 25% by engine parameter adjustments. Further, the emission reduction was even higher when the target for adjusting engine parameters was to exclusively reduce either particulates or NO(x). In addition to particulate mass, different indicators of particulate emissions were also compared. These indicators included filter smoke number (FSN), total particle number, total particle surface area, and geometric mean diameter of the emitted particle size distribution. As a result of this comparison, a linear correlation between FSN and total particulate surface area at low FSN region was found.

Effects of hydrotreated vegetable oil on emissions of aerosols and gases from light-duty and medium-duty older technology engines

“…[26,28–30] However, the majority of those studies reported effects of the NO X emissions, but none reported separately the effects on two major NO X components: NO and NO 2 . Due to the relatively high toxicity [34] and technical and economic issues related to ventilation, the NO 2 emissions are of particular concern in the case of confined occupational environments.…”

“…Those engines were not adjusted to compensate for the substantial differences in physical and chemical properties between test fuels. Independent studies [26,30] have shown that engines with modifications made to compensate for changes in fuel properties, such as increasing injection pressure, theoretically, have the potential for relatively minor additional reductions in DPM emissions on top of those achieved by using HVORD in place of ULSD. The practices with FAME biodiesel fuels showed that mine operators in the U.S. are unlikely to invest into optimization of in-use engines to specific fuels.…”

“…Several studies showed that regulated emissions can be further reduced via optimization of fuel injection and other engine parameters. [26,30] …”

Effects of FAME biodiesel and HVORD on emissions from an older-technology diesel engine

“…HVORD is favored over FAME biodiesel due to lower environmental impact (Yano et al, 2015). Compared with ULSD, HVORD has favorable effects not only on particulate, carbon monoxide and total hydrocarbon emissions but also NO X emissions (Aatola et al, 2008; Happonen et al, 2012; Kim et al, 2014; Westphal et al, 2013; Bugarski et al, 2015). Westphal et al (2013) found that HVORD particulate extracts have lower mutagenicity than ULSD and rape-seed and jatropha FAME biodiesel particulate extracts.…”

Study of Miller timing on exhaust emissions of a hydrotreated vegetable oil (HVO)-fueled diesel engine

“…They reported that NO x emission reduced by 25-45% depending on load and on the IVC timing of the Miller cycle, but filter smoke number (FSN) increased simultaneously. Happonen et al (2012) studied the effect of advanced intake valve closing and fuel injection timings on exhaust emissions with an engine run with HVO fuel. They obtained notable reductions with all tested loads in PM and NO x emissions by combining advanced intake valve closing and fuel injection timings with EGR.…”