The main purpose of this research is to study the effect of various blends of an environmental friendly alternative fuel “methyl ester” on the performance of a heavy diesel engine. The biodiesel was obtained from a chemical process: the transesterification of waste oils (frying oils). Tests were conducted on an engine test bench in accordance to DIN 2020 standards. Results obtained demonstrate that the biodiesel gives very interesting ecological advantages but engine performance was reduced slightly comparatively to those obtained with a pure diesel fuel. We have noted about 5% decrease in power and torque and about 2% in Nox emission for every 10% of biodiesel blend added comparatively to pure diesel. However, the use of biodiesel has slightly increased specific fuel consumption (about 6% for every 10% of biodiesel blend added).

Three chemical kinetic mechanisms of methane combustion were tested and compared using the internal combustion engine model of Chemkin 4.02 [1]: one-step global reaction mechanism, four-step mechanism, and the standard detailed scheme GRIMECH 3.0. This study shows good concordances, especially between the four-step and the detailed mechanisms in the prediction of temperature and main species profiles. But reduced schemes were incapables to predict pollutant emissions in an internal combustion engine. The four-step mechanism can only predict CO emissions but without good agreement.

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