Emission measurements of naturally aspirated and turbo-charged diesel internal combustion engines for various biodiesel blends

Abstract

Biodiesel blends and pure biodiesel fuels are currently used in diesel internal combustion engines (ICE), and the European Union imposes a usage lower limit of 7% by volume of biodiesel fuel blend in diesel fuel. The objective of the present study is to examine and quantify the effects of biodiesel blends on the emissions and performance of two different types of diesel ICE, namely naturally aspirated and turbo-charged. Methanol-based biodiesel was produced in the laboratory of Frederick University by chemical processing of raw materials. The biodiesel fuel was used for blending pure diesel fuel at various percentages, and four test fuels were used for the experimental investigations, namely pure diesel, 25% by volume of biodiesel in diesel, 50% by volume of biodiesel in diesel and 75% by volume of biodiesel in diesel, denoted B0, B25, B50 and B75, respectively. The test fuels were used for smoke emissions measurements of the two diesel engines at increasing engine speed and for increasing engine temperature. A gas analyser utilising an opacimeter was employed for the experimental measurements. For the two diesel engines, similar trends in the emitted smoke for increasing engine temperature and increasing engine speed were observed, and the emitted smoke decreased when the biodiesel blending percentage was increasing. However, at high engine speeds, the naturally aspirated engine smoke emissions were by almost a factor of two higher than the emitted smoke by the turbo-charged engine. Based on the experimental results, conclusions are drawn and recommendations are provided for the application of biodiesel blends in diesel engines.