Method of Optimizing Turbocharged Engine Systems

In order to utilize exhaust gas energy effectively, various engine systems equipped with exhaust gas turbines have been proposed. Since their performance depends greatly on the matching technique, the authors have been developing a method of optimizing these systems on the basis of mathematical treatments. The purpose of this paper is to describe a mathematical optimization procedure and to show its application to a turbocharged engine. This method consists of three steps : (1) choice of parameters representative of turbine and compressor characteristics, (2) efficient estimation of their behavior, (3) parameter optimization. The method was shown to have the capability of optimizing the engine system efficiently and to possess both flexibility and generality.