Application of Injector-Volume Ratio Values in the Development of a Fuel Injection Controller

The primary function of an electronic control unit (ECU) of an engine is to calculate the amount of fuel to be delivered into the combustion chamber. The injection duration and duty cycle of the injector will be based on several sensors whose signals the ECU will process to ensure the best engine running condition. However, to study new injection and combustion strategies, where such operation is unavailable in standard ECU, a custom-built fuel injection control system need to be made. This paper describes the development of a fuel injector signal controller, which is being used for internal combustion engine experiment or for the evaluation of any fuel injector static flow rate. Herewith a new term Injector-Volume Ratio (IVR) was introduced to assist the development process. Using the custom-built fuel injection controller, the static flow rate of an injector for a single cylinder 125cc motorcycle engine was determined in accordance to SAEJ1832. From the experiment, the IVR value is proven useful in choosing the right size of a fuel injector to fit any specified engine displacement of a spark ignition engine.