Fuel injection rate variation and energy consumption of solenoid in a diesel solenoid injector with injector driving current patterns

Injected fuel mass per stroke (IFMPS) was measured by varying the driving current pattern of a solenoid-type diesel common rail injector. Repeated measurements of IFMPS were statistically analyzed to determine deviation from the average. The control of the injector’s driving current waveform was achieved through pulse width modulation (PWM) on the microcontroller’s CCP (capture compare and PWM) pin. The solenoid injector driving current pattern took the form of a peak & hold shape. A total of 36 types of driving current patterns were generated by manipulating peak and hold conditions in different combinations, and each driving current waveform was applied to drive injector. To evaluate the solenoid’s thermal dissipation characteristics, the injector solenoid’s driving energy was calculated by integrating the injector’s driving current waveform over time. The IFMPS per energy consumed by the solenoid was then calculated based on the injector driving current waveform, defining it as the thermal parameter for injector solenoid (TPIS). The TPIS value can be used as a reference to identify the optimal injector drive current pattern concerning the solenoid’s thermal dissipation. The fuel rail pressure was controlled at three levels: 40, 80 and 120 MPa.