Influence of the Phosphorus Content in Rapeseed Oil Methyl Esters During a 1000 Hours Endurance Test on the Function of a SCR-system Measured by Exhaust Gas Emissions and Health Effects

Two batches of rapeseed oil methyl esters containing approximately 10 ppm phosphorus (RME₁₀), one rapeseed oil methyl ester with a content of less than 1 ppm phosphorus (RME) and common diesel fuel (DF) were investigated regarding their effects on regulated and non-regulated emissions of a modern diesel engine (Euro IV) equipped with an SCR system (selective catalytical reduction of nitrogen oxides). The regulated emissions of carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NO_x) and particulate matter (PM) were determined for RME₁₀ and DF. Non-regulated emissions alkenes, alkynes, aromatics, aldehydes, ketones and the particle size distribution were measured for all fuels. Additionally the mutagenic potency of the PM emissions was determined using the Ames test.

RME₁₀ led to lower regulated emissions than conventional diesel fuel. Regarding the non-regulated emissions RME showed the lowest values compared with RME₁₀ and DF. The catalytic activity of the SCR system was reduced after an endurance test of 1000 hours using RME₁₀ as fuel resulting in higher regulated and non-regulated emissions.

The mutagenicity of all PM extracts was very low compared to prior studies probably due to an effective PAH conversion by the SCR system. Nevertheless, mutagenic effects of PM extracts increased moderately after the endurance test.