The Impact of Biodiesel on Automotive Catalyst Performance Essay

Stringent diesel emissions regulations around the world have put much pressure on the shoulders of manufactures to reduce the level of emissions entering the atmosphere from diesel engines. Much of the initial attempt to achieve this by the manufactures was by the substitution of biodiesel in place of the conventional petroleum diesel. In order to create a balance between the vehicle performance and the imposed emissions regulations, many manufacturers prefer to blend petroleum diesel with biodiesel in a proportion which is deemed suitable to run on their engines. In a statement from the diesel fuel injection systems manufacturer’s association, they suggested that diesel fuel specification should be updated on a regular basis, to allow for the gradually increasing percentage of biodiesel. By so doing injection components could be manufactured such that they are protected from the possible secondary effect of the fatty acid methylesthers, which includes filter plugging due to softening and corrosion of zinc or aluminium parts in the fuel injection system due to the presence of free menthol residues. Whilst biodiesel has been highlighted as a plausible substitute for petroleum diesel, great concerns still arise over the effects of its emissions on health and environment, considering the fact that only a few of its hydrocarbon emissions are yet known. Studies about the effects of increasing biodiesel blend ratio on the operation and emissions of diesel engines have been documented in a vast amount of published and unpublished literature since the 1980’s (1), (2), (3). A general trend of observation amongst most of the literatures reviewed is a reduction in CO and THC emissions with increasing biodiesel blend ratio, like wise incre... ...ation of after treatment systems have been proposed by some researches, as a viable solution in reducing CO, THC and NOx emissions to a non-harmful level. Some of these proposed after treatment systems include DPF (Diesel particulate filter) and DOC (Diesel Oxidation Catalyst). Amy et al’s (27) research in to effect of biodiesel emissions on the performance of a diesel particulate filter in a diesel engine, showed that increased biodiesel blend ratio produced less soot and thus required a lesser regenerative temperature, when compared to the conventional petroleum diesel. Their conclusions indicated the fact that with biodiesel fuels, the regeneration of particulate filters could be carried out without the fear of causing an over heat in the exhaust system. They applauded the reactive nature of the biodiesel soot, as a major contributor to this trend.