Design of an ESP32-based electronic control system for evaluating motorcycle fuel injector characteristics

The development of electronic fuel injection (EFI) technology and the growing use of ethanol-blended fuels have introduced new challenges for motorcycle fuel systems, particularly injector performance and reliability. Commercial injector testers are relatively expensive and often use closed architectures, limiting their accessibility for small workshops and educational laboratories. This study aimed to design and develop a web-based injector characteristic testing control system using an ESP32-S3 CAM microcontroller and to evaluate its performance. An engineering design method with a quantitative testing approach was applied. The system was designed to conduct fuel volume, spray pattern, and leakage tests by controlling engine speed simulation (RPM), duty cycle, and test duration through a web interface. The ESP32-S3 CAM generated pulse-width modulation (PWM) signals to actuate the injector and provided real-time visual monitoring through an integrated camera. The results showed that the system successfully executed the intended testing functions. Increasing RPM, duty cycle, and test duration produced proportional increases in injected fuel volume. Linearity analysis indicated that injector responses were generally linear with respect to changes in RPM and duty cycle. Repeatability testing produced maximum coefficient of variation values of 1% for injector 1 and 2% for injector 2, indicating good measurement consistency. Spray pattern testing showed a uniform cone-shaped atomization pattern. In contrast, leakage testing confirmed the absence of fuel droplets under inactive conditions. These findings demonstrate that the developed ESP32-based tester provides a low-cost, flexible, and practical alternative for evaluating motorcycle injector characteristics in workshop and laboratory settings, especially where standardized diagnostic equipment is not readily available.