STUDY OF IGNITION DELAY IN ENGINES USING BIODIESEL

Resumo

In direct injection diesel engines, where fuel is injected directly into the combustion chamber, one of the problems they may present is the ignition delay, defined as the time interval between the start of fuel injection and the start of combustion. This ignition delay is an important factor in determining diesel engine performance characteristics such as fuel conversion efficiency, smoothness of operation, misfire, smoke emission, noise and ease of start. It is in the technological context of the analysis of the delay of ignition with the use of biodiesel that the study is based. The objective of this study was to quantify and analyze the ignition delay in compression ignition engines when using biodiesel blends (B3, B10, B20 and B50) and pure soy biodiesel (B100) by means of theoretical correlations found in the literature. Delay values are calculated by three theoretical correlations, in nine operating conditions, corresponding to 1500, 2000 and 2500 rpm and 25%, 50% and 75% of the maximum engine torque. Subsequently, these results are compared with experimental data of ignition delay, obtained from pressure curves of an already performed research. From this comparison, the limitations and adjustments of each model of correlation evaluated are analyzed and indicated when using blends of fuels containing biodiesel and pure soy biodiesel.