Influence of fuel properties and composition on NOx emissions from biodiesel powered diesel engines: A review

Biodiesel has proved to be an environment friendly alternative fuel for diesel engine because it can alleviate regulated and unregulated exhaust emissions. However, most researchers have observed a significant increase in NOx emissions with biodiesel when compared to petrodiesel. The exact cause of this increase is still unclear; however, researchers believe that the fuel properties have been shown to effect the emissions of NOx. The present work reviews the effect of fuel properties and composition on NOx emissions from biodiesel fuelled engines. The paper is organised in three sections. The first section deals with the NOx formation mechanisms. In the following section, the reasons for increased NOx emissions of biodiesel fuel are discussed. After this, the influence of composition and fuel properties on NOx emissions from biodiesel fuelled engines has been reviewed. Finally, some general conclusions concerning this problem are summarised and further researches are pointed out.