Justification for Widening the Control Parameters Limits of Diesel Fuel Injectors During Repair.

The fuel injectors of diesel engines and other components of fuel supply systems require diagnostic and repair during operation. The actual technical condition and the quality of the fuel injectors' repair are mainly determined by the accuracy of the Test Plan control values, usually provided by manufacturing plant. For various reasons, the factory Test Plans do not meet the requirements of new and operating fuel injectors, which narrows the deviations of their control parameters during testing. Five diagnostic indicators identified during the research were used to assess the technical condition of various fuel injector types. These indicators depend significantly on twenty-four structural parameters. Evaluation criteria for each identified parameter were established. Experimentally confirmed computational and numerical studies allowed determining their permitted deviations from the control values, which kept the final fuel injector operating results within limits specified by the manufacturer. Thus, the Bosch fuel injector testing proved that the factory Test Plan values could be significantly widened without changing the output fuel injector operating results. The study allowed compiling a table summarizing the wide tolerances of the Bosch fuel injector control parameters. The table contains information on the operating mode of this fuel injector during testing. The data obtained make it possible to develop softer recommendations for fuel injector repair and refuse using unreasonable rigid test plans provided by manufacturers. [ABSTRACT FROM AUTHOR]