An Experimental Study on the Impact of Biodiesel Origin and Type on the Exhaust Emissions from a Euro 4 Pick-up Truck 2010-01-2273

This study investigates the impact of mid-high biodiesel blends on the criteria and PAH emissions from a modern pick-up diesel vehicle. The vehicle was a Euro 4 (category N1, subclass III) compliant common-rail light-duty goods pick-up truck fitted with a diesel oxidation catalyst. Emission and fuel consumption measurements were performed on a chassis dynamometer equipped with CVS, following the European regulations. All measurements were conducted over the certification New European Driving Cycle (NEDC) and the real traffic-based Artemis driving cycles. Aiming to evaluate the fuel impact on emissions, a soy-based biodiesel, a palm-based biodiesel, and an oxidized biodiesel obtained from used frying oils were blended with a typical automotive ultra-low-sulfur diesel at proportions of 30, 50 and 80% by volume. The experimental results revealed that CO₂ emissions and fuel consumption exhibited an increase with biodiesel over all driving conditions. NO

emissions were found to be above the Euro 4 limit and increased with biodiesel except the blends prepared with the palm-based methyl ester. In general, the emissions of PM, HC, and CO decreased with the addition of biodiesel; however, some increases were observed over the NEDC which may be attributed to the cold-start conditions during the first phase of the cycle, along with certain physicochemical characteristics of biodiesel. Regarding the unregulated emissions, the results showed that the application of biodiesel may negatively affected the toxicological characteristics of diesel particulate matter due to potential increases of certain toxic compounds in its composition. Sharp increases in most PAH, nitro-PAH and oxy-PAH compounds were observed with the application of biodiesel. These increases were particularly noticeable with the use of the oxidized blends, a phenomenon that it is related with the type and quality of this fuel. The emissions were also affected by the operating conditions of the engine. It was found that most PAH compounds were decreased as the mean speed and load of the driving cycle increased.