Advanced biofuels have gained importance as a solution to reduce fossil fuel consumption in vehicles, mainly with the enforcement of the recent EU Renewable Energy Directive (2018/2001). This directive establishes a contribution of renewable energy of 14% in rail and road transport by 2030, encouraging the use of biofuels with non-crop and waste origin (with a contribution of at least 3.5% and multiple counting). Medium-long chain bio-alcohols produced from wastes or lignocellulosic raw material through bacterial fermentation or from green-H2 and captured-CO2 (this latter compounds usually denoted as electro-fuels), are a good option to be used in diesel vehicles. Although renewable ethanol is the typical alcohol blended with diesel fuel, n-butanol offers better properties such as a higher cetane number, higher heating value, better lubricity and better miscibility with diesel fuel. In parallel, last European emission regulations for light-duty diesel vehicles have become much more restrictive regarding NOx (the limit moved from 180 mg/km in Euro 5 to 80 mg/km in Euro 6). Internal techniques affecting the combustion development like exhaust gas recirculation (EGR) and complex injection strategies are not enough to fulfil the current regulation, so vehicle manufacturers have been forced to incorporate DeNOx aftertreatment systems consisting of lean NOx trap (LNT) and/or selective catalytic reduction (SCR). Because of current compression ignition vehicles have been optimized to operate with conventional diesel fuel, the combination of modern DeNOx devices and the upcoming higher contribution of advanced biofuels is a new challenge still unknown. &nbsp;Moreover, cold ambient conditions, for which the properties of alcohols could be a drawback, will be implemented in forthcoming emissions regulations. Considering these aspects, two different Euro 6 diesel vehicles (SUV segment), one equipped with LNT and the other with ammonia-SCR, have been tested following the Worldwide harmonized Light-duty vehicles Test Cycle (WLTC) at warm (24ºC) and cold (-7ºC) conditions using conventional diesel fuel and a diesel-butanol blend with 10% by vol. of the latter (selected in previous work as an optimal content). The vehicles performance and regulated pollutant emissions as well as the DeNOx systems efficiency were analysed and discussed. Results provide relevant information about the compatibility of current vehicles to these new fuels as well as for the optimization of future diesel vehicles. While the effect of butanol on the LNT efficiency was not significant, its influence on the SCR performance was notable during the low and medium-speed phases of the driving cycle, mainly under warm climatic conditions. This behaviour could be attributed to differences in the hydrocarbons content at the SCR inlet, which could inhibit the NOx reduction reactions with ammonia.

Effect of Butanol on the Performance of DeNOx Aftertreatment Systems of a Diesel Vehicle Under WLTC Driving Conditions

Paper Proceedings: https://asmedigitalcollection.asme.org/ICEF/ICEF2021/volume/85512

ASME 2021 Internal Combustion Engine Division Fall Technical Conference (ICEF2021)

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.