Regulated, carbonyl and polycyclic aromatic hydrocarbon emissions from a light-duty vehicle fueled with diesel and biodiesel blends

This study investigates the impact of low concentration biodiesel blends on the regulated, carbonyl and PAH emissions from a modern passenger vehicle. The vehicle was a Euro 4 compliant SUV type fitted with a common-rail diesel engine and a diesel oxidation catalyst. Emission and fuel consumption measurements were performed on a chassis dynamometer using a constant volume sampling (CVS) technique, following the European regulations. All measurements were conducted over the NEDC and Artemis driving cycles. Aiming to evaluate the fuel impact on emissions, a soy-based biodiesel was blended with an ultra low sulphur diesel at proportions of 10 and 30% by volume. The experimental results revealed that emissions of PM, HC and CO decreased with biodiesel over most driving conditions. Some increases were observed over the NEDC which may be attributed to the cold-start effect and to certain fuel characteristics. NO x emissions were found to be higher with biodiesel especially during Artemis operation. CO 2 emissions and fuel consumption followed similar patterns and increased with biodiesel. Most carbonyl compound emissions increased with biodiesel, with the exception of aromatic aldehydes. It was found that carbonyl emissions decreased as the mean speed and load of the driving cycle was increased. Most PAH emissions were found to be lower with biodiesel, however, some increases were observed for certain toxic compounds. This study attempts to address the issue of mid-low concentration biodiesel blends application in modern passenger cars and their potential impact on the criteria and unregulated exhaust emissions and air pollution.