Validation of indirect methods used in the operational assessment of LPG vapor phase pulse injectors

Engine adaptation for alternative fueling may generate certain difficulties in terms of configuration or quality of the subassemblies. The main actuator of a modern LPG (Liquefied Petroleum Gas) system is the vapor phase injector. These systems are commonplace because of the possibility of a modification of the mixture composition in order to meet the emission standards. Multitude of injector design solutions and quality of their workmanship frequently make them the main reason for system malfunction, hence, the need to apply simplified research methods in the course of operation that would allow an assessment of their technical condition. The paper directly compares selected research procedures evaluating their applicability. The proposed method of pressure measurement at the outlet of the injector nozzle turned out to be sufficient for a non-invasive assessment of the technical condition of the injector, which was confirmed by the measurement of the injector piston lift by the displacement sensor. The current on the power line and the vibrations of the injector housing have been sufficient to diagnose the subassembly, thus supporting the decision on the extent of the repair.