Abstract
This study explores the behavior and evolution on the quality of premium spark-ignition engine gasoline distributed in Costa Rica during the period 2006 to 2010. Traditionally, fuel behavior studies are done on univariate and bivariate statistical methods but fail to provide sufficient information to describe the relationship between the attributes and multidimensionality of the individuals’ behavior information. To overcome this limitation, a principal component analysis (PCA) is performed using the data gathered during the five years of the study. Additionally, an automatic classification by an ascending hierarchical classification, using the Ward method and the classical euclidean distance was performed to determine the behavior of individuals when forming groups with similar characteristics. Based on the analysis, it is found that premium gasoline evolves toward a less contaminant fuel where the main improvement is the reduction in olefins and benzene content. However an increase in the composition of heavy fuel fractions is observed, resulting in an increment in the second half of the distillation curve and in the distillation residue. All centers of gravity are kept within the limits of the current regulations.