Methodology and Results of F-34 Fuel Impact on the Reliability of the Engine Injection System on the Non-Engine-Based Test Stand

The study of the F-34 aviation fuel used to power a diesel engine requires an extensive testing programme be carried out in the steady and transient states of the engine operation. The researches of the engines are expensive therefore, the tests can be also performed on the non-engine-based stand at a lower price.

The design of the non-engine-based test stand and the methodology of the engine injection system testing follow the AEP-5 qualifying test has been described in the paper. The measurement methods used on the stand and the selected measurement results are presented. The tests have included checking the changes of three basic sets of the injection systems that may be subject to wear during the operation of the system. This applies to the following assemblies: jet needle - injection nozzle body, delivery valve plug - carrier, injection pump plunger and barrel. The non-disassembly measurement methods used to assess the state of wear of the injection system assemblies have been set forth. The wear of the injectors has been estimated on the fuel pressure drop before the injector and an amount of the fuel leaking through the injector during one cycle. The delivery valve tightness has been evaluated on the fuel pressure drop before the pressure valve bracket. The barrel-plunger assembly wear has been assessed on the fuel maximum injection pressure and average fuel charges. The fuel temperature has been measured in the small fuel tank calming fuel injection. Based on the results of the measurements made in respect of F-34 fuel, it has been found that there is no impact of the tested fuel on the wear of the injection system units. F-34 fuel can be used to power piston engines without any changes made to these engines. In comparison, some measurement results in respect of IZ-40 diesel fuel are presented.