Fuel Consumption Monitoring System Using Control Signal and Characteristic Correlations of Fuel Injector

Abstract

Objectives of this study are (i) to investigate characteristics of a fuel injector and to establish the characteristic correlation for correcting the fuel injection rate calculated from the control signal of a fuel injector, and (ii) to design and fabricate the fuel consumption monitoring system by measuring the control signal of a fuel injector in conjunction with considering the obtained characteristic correlation to enhance accuracy of the measured fuel consumption rate. The characteristics of a fuel injector, e.g., engine speeds, percentages of injector’s duty cycle, and pressure differences between fuel rail and intake manifold, were experimentally investigated on a test set in the laboratory. The study found that when the engine speed increased, the fuel injection rate increased. This trend was not agreed with the ideal trend due to the inertia of an injector’s needle that caused the closing phase duration of the injector to be longer. When the percentages of injector’s duty cycle increased; although the fuel injection rate increased as the ideal trend, the increasing ratio was less than the one-to-one increasing ratio as a case of the ideal due to the cavitation effect in the fuel passage inside the fuel injector that caused obstacle to the fuel injection. Moreover, when the pressure difference increased, the fuel injection rate increased. After that, the fuel consumption monitoring system was designed and fabricated based on the Arduino Mega 2560 microcontroller. Trip distance was measured by a GPS module. The real-time fuel consumption rate could be shown on a LCD display. All recorded data were stored onto a SD card for further data analysis. Finally, it was found from the on-road-test validation that the average discrepancy of the measured fuel volume was ± 1.88% compared to the actual fuel volume obtained by measuring a decreasing volume of consumed fuel.