A comparative study of the detection of the fuel-injection start and stop timing of a diesel injector using a photo sensor, a shock sensor and a needle lift sensor

The fuel-injection start and stop timings of a diesel injector were measured using a photo sensor, a shock sensor, and a needle lift sensor. The fuel spray jet was detected by installing a photo sensor at the position closest to the fuel spray jet exiting the diesel injector nozzle hole. The shock sensor was mounted outside of the injector holder assembly and the fuel injection timing was measured by detecting the shock wave generated when the injector needle moved. The injector needle lift was measured by using an injector with a built-in needle lift sensor (TDI G80 sensor). The G80 sensor has an integrated solenoid allowing the detection of the movement of the injector needle. As the injector needle moves, an electrical signal is induced from the solenoid and the voltage is measured. The photo sensor, shock sensor, and needle lift sensor all confirm that the timing of the start of fuel injection by the injector can be accurately measured. The fuel injection stop timing could be measured by the photo sensor and the needle lift sensor. The variation of the fuel injection stop timing was greater than that of the fuel injection start timing. The shock sensor could not accurately measure the fuel injection stop timing. The detecting time order of the start of the fuel injection by the three sensors was in order of the needle lift sensor, the shock sensor and the photo sensor.