A simulation and experimental study is conducted on a natural gas fuel injection system. The injection system includes a rail tube, a solenoid gas injector and an electric pressure regulator (EPR). The purpose of this study is to examine the operating characteristics of the injection system such as EPR control voltage, EPR plunger displacement, gas pressure in the rail tube, and injection flow rate. Mathematical models are established to describe the operation of solenoid gas injector and EPR. Besides, a control model is built to examine the response as well as injection pressure controlled by EPR. These models are solved in MatlabSimulink. Effects of EPR design parameters such as spring stiffness and plunger mass on the operating characteristics of the gaseous fuel injection system are investigated. The simulation results show that the operating performance of the gaseous fuel injection system can be improved if EPR spring stiffness and plunger mass are suitably chosen. In addition, the electric pressure regulator can be successfully controlled to maintain a stable output pressure providing to the solenoid injector. The simulation results are validated with experimental results for the controlled gas pressure.
Keywords Solenoid injector, injection system, pressure regulator, plunger mass, spring stiffness