Impact of RME biodiesel on the concentration of particulates and nitrogen oxides in compression ignition engine exhaust fumes

Abstract

Reciprocating engines with compression ignition are currently in common use. However, they are a significant source of harmful environmental impact. They have a substantial share in the total emissions of particulates and nitrogen oxides into the atmosphere, thereby affecting human health and life, it means ecological safety. Rigorous standards impose the limitation of emissions of harmful compounds by combustion engines used in transport. Therefore, there is search for solutions that will limit the negative effects of using compression ignition engines. One of such solutions is the use of renewable fuels in the form of vegetable oils’ fatty acid esters. The purpose of the paper was to demonstrate the impact of using rapeseed oil’s fatty acid methyl esters with no additives on the concentration of particulates and nitrogen oxides. The testing was conducted for a state-of-the-art compression ignition engine equipped with the Common Rail fuel supply system used for passenger cars. During the testing, the engine was operating at varying loads and constant crankshaft speed at which the engine achieves its maximum torque. The fuel compared to the measurement results for esters was diesel fuel without biofuel additives. Fuelling the engine with esters allowed for increasing the nitrogen oxides’ concentration in the exhaust fumes. Simultaneously, it allowed for obtaining substantially lower concentrations of Soot, soluble organic fractions and total particulates content. The concentration of hydrocarbons was also halved. The use of esters is a good fuel alternative for supplying compression ignition engines. Esters constitute renewable fuel obtained from organic matter and favourably affect the balance of carbon dioxide in the atmosphere.