Biodiesel emissions profile in modern diesel vehicles. Part 1: Effect of biodiesel origin on the criteria emissions

This paper presents the regulated emissions profile of a Euro 4 compliant common rail passenger car, fuelled with low concentration biodiesel blends. Four biodiesels of different origin and quality blended with a typical automotive diesel fuel at proportions of 10, 20, and 30% v/v. Emission and fuel consumption measurements were conducted on a chassis dynamometer with constant volume sampling (CVS) technique, over the New European Driving Cycle (NEDC) and the real traffic-based Artemis driving cycles. Limited effects were observed on CO2 emissions, while fuel consumption marginally increased with biodiesel. PM, HC and CO emissions improved with the addition of biodiesel, with some exceptions. Some increases with biodiesel were observed over the NEDC, as a consequence of biodiesel characteristics and engine conditions. NOx emissions were increased with the use of biodiesel blends and positively correlated with fuel unsaturation levels.

Research Highlights
► NOx emissions for the saturated blends were similar to those of diesel fuel.
► Higher NOx emissions for the unsaturated and oxidized biodiesel blends.
► Presence of oxidation products favors the formation of NOx.
► PM reductions with the use of biodiesel blends due to the presence of oxygen.
► Some increases for PM, HC, and CO emissions during cold-start.