Hydraulic Characterization of Solenoid-actuated Injectors for Diesel Engine Common Rail Systems

Injection systems represent key elements in modern diesel engines because of the fundamental role played in fuel spray formation and evolution during the combustion phase. For this reason, their design needs attention and continuous improvements in order to satisfy environmental standards and consumer demands. The present work illustrates the main phases that form the basis of an activity of hydraulic characterization of a solenoid injector for diesel engine applications. The performance of the injection system has been verified by means of injected flow-rate time histories, fuel injected quantities, leakages through the injector pilot-valve, electric driving signals and pressure transients, for different operating conditions, which refer to single and multiple injections. Furthermore, a complete numerical model of the injector and of the high-pressure hydraulic circuit of the injection apparatus has been developed with the aim of deepening the understanding of the internal dynamics of the injection system, which could not be analyzed only experimentally.