ENERGY EFFICIENCY IN GASOLINE DIRECT INJECTION ENGINES

The growing awareness about the environmental impact of human activities and their influence on the increased concentrations of greenhouse gases (GHGs) has recently affected research efforts in the transportation field. Knocking in gasoline direct ignition (GDI) engine, is a kind of abnormal combustion that can restrict engine energy efficiency. It can also lead to permanent engine damage, under specific operating conditions. This paper focuses on the state of the art of engine knock research, considering the causes, influencing aspects, effects and methodology to predict and to reduce the probability of occurrence of this phenomenon. We present some examples of experimental procedures that were followed to analyze this event, through visualization images that can be supported by numerical activity, consisting of fluid dynamic simulation of the combustion process. Different systems to measure engine knock intensity and some mathematical models to predict abnormal combustion, in order to improve engine performance, are analyzed. Finally, in this work we try to give new perspectives for future research, through the use of different techniques to achieve knocking reduction.