Development of custom-made engine control unit for a research engine

In this paper, hardware development, software coding using embedded C programming language for an Arduino ATMEGA microcontroller, calibration of electronic control unit (ECU) was tested for a research engine to control the fuel injection flow rate with respect to the suction top dead center (TDC) of the engine. The system could control the fuel flow rate with a variable reluctance sensor, an Arduino microcontroller and a solenoid operated injector in a closed loop domain with a varying pulse width modulator controlled exclusively by the engine operator. The injection flow rates were measured and calibrated with the calculated fuel flow rates for different equivalence ratios (Ø) of the engine. The results showed a very close match between the measured fuel flow rates after calibration and the calculated fuel flow rates at 1500 RPM. The gasoline mass flow rate error was reduced from 40% to 3.25% by compensating the ON/OFF time of the pulse width.