Chemical Characteristics of the Soot Produced in a High-Speed Direct Injection Engine Operated with Diesel/Biodiesel Blends

Abstract

The aim of this work is to study the influence of the molecular structure of fatty acid esters present in biodiesel and their blends with diesel on the chemical characteristics of the emitted particulate matter. Biodiesel produced from palm oil, jatropha, castor oil and sachainchi was blended at 5% and 20% by volume with diesel. These fuels were used for the operation of a four-cylinder direct injection automotive diesel engine. The equivalent ratio was kept between 0.36 and 0.40, and the engine was operated at the point of minimum air–fuel ratio and maximum smoke opacity. The amount of particulate matter emitted was evaluated by opacity index. A marked reduction in soot formation was observed when the concentration of unsaturated methyl esters in the fuel was at low concentrations. This was accompanied by a reduction of the aliphatic carbon content in the particulate matter.

Keywords:

• Biodiesel
• Chemical characterization
• Chemical structure
• Direct injection engine
• Particulate matter

ACKNOWLEDGMENTS

The authors want to thank the Colombian Ministry of Agriculture and Rural Development and the Environmental authority from Medellín (Área Metropolitana del Valle de Aburrá) for the financial support of project No. 003 2007D3608-67-07 (Biodiesel project). The authors also would like to thank the Sostenibilidad Program 2012–2013 of the University of Antioquia for financial support. M.S. thanks COLCIENCIAS and the University of Antioquia for the Ph.D. scholarship.

Notes

*Values obtained for XRF data.

Published as part of the Seventh Mediterranean Combustion Symposium Special Issue with Guest Editors Federico Beretta, Nevin Selçuk, Mohy S. Mansour, and Andrea D'Anna.