Common Feeding Injection System Equipped with Reduced-Leakage Solenoid Injectors 2014-01-2735
A numerical-experimental analysis of a new generation Common Feeding (CF) fuel injection system, equipped with last generation solenoid injectors that feature pressure-balanced pilot-valves, has been developed.
The main feature of the CF system is that it removes the accumulator from the high-pressure layout of the standard Common Rail (CR). In the CF apparatus, the high-pressure pump is connected directly to the injectors, and a small accumulation volume is integrated in the pump high-pressure circuit. The hydraulic performance of the CF system, including the injectors with the pressure-balanced pilot-valve, has been compared with that of the standard CR system in terms of injected masses, fuel leakages, high-pressure and injected flow-rate time histories.
A previously developed advanced one-dimensional code for CR type systems has been adapted for the simulation of the CF high-pressure layout. Furthermore, electromagnetic, hydraulic and mechanical submodels have been set up for the pressure-balanced pilot-valve simulation. This new pilot-valve configuration is aimed at reducing injector fuel leakages and at improving the dynamic response of the needle to the electrical command.
The complete numerical model of the CF system has been validated by means of comparison with experimental data that have been acquired at the hydraulic test bench. Hence, the validated model has been applied to investigate the internal fluid-dynamics of the pressure-balanced solenoid injector, when inserted into the CF setup, as well as the effects of some design modifications in the high-pressure hydraulic circuit of the CF system.