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The selection and tuning of the Fuel Injection System (FIS) are among the most critical tasks for the automotive diesel engine design engineers. In fact, the injection strongly affects the combustion phenomena through which controlling a wide range of related issues such as pollutant emissions, combustion noise and fuel efficiency becomes feasible. In the scope of the engine design optimization, the simulation is an efficient tool in order to both predict the key performance parameters of the FIS, and to reduce the amount of experiments needed to reach the final product configuration. In this work a complete characterization of a solenoid ballistic injector for a Light-Duty Common Rail system was therefore implemented in a commercially available one-dimensional computational software called GT-SUITE. The main phenomena governing the injector operation were simulated by means of three sub-models (electro-magnetic, hydraulic and mechanical).

The injection rate modulation and the spray characteristics are determining factors for the quality of mixture formation when applying GDI. Their variation with load and speed is a basic criterion for the adaptability of a type of injection system to an engine with known requirements. The increased interest for the utilization of regenerative fuels - such as methanol obtained from biomass - as well as the success of previous utilization scenarios of variable gasoline/methanol mixture using manifold injection formed the base of the present analysis: the paper describes the results concerning injection performances and spray characteristics when using gasoline/methanol mixtures with different ratios in a direct injection system with high pressure modulation. The results are compared for different parameters of the injection systems as follows: injection volume, injector opening pressure, needle lift, pintle/seat geometry.