The determination of the flow characteristics of a low-pressure vapor-phase injector with a dynamic method

Currently, the most widespread alternative fuel systems for combustion engines are low-pressure gas ones. When configuring such types of systems or when attempting to initiate simulation research, the flow characteristics of individual subassemblies, particularly the injectors need to be known. The equipment manufacturers only provide the volumetric flow rate at a given pressure without indicting whether the measurement was carried out under standardized guidelines. Therefore, the author attempted to determine the flow characteristics of low-pressure vapor-phase injectors using the 'tank' method following the guidelines of the JIS B 8390 standard. The copyrighted algorithm of throughput identification has been developed based on the flow model using the lumped elements method. Characteristics were determined depending on the injection time and depending on the opening frequency of the injector and linear increments in the investigated ranges were observed. The coefficient of determination adjusted to the degrees of freedom in both cases exceeded 99.9%. Compliance of the measurements using the proposed method with the flow meter measurements was confirmed. The maximum differences sometimes exceeded 5%. The paper presents the variability of the mass flow depending on the injection time and depending on the opening frequency of the injector. This is a basis in the course of modeling of the operation of engines or the assessment of the fuel consumption in simulation models of standardized driving cycles.