Artigo:

Normally diesel injectors are tested with higher internal pressure levels at test bench than usual at work conditions, to verify any possible leakage regarding process deviation. During this test, some injectors shown micro leakage at interface between injector and nozzle bodies. However, the same injectors do not show leakage when assembled at engines. Besides the higher internal pressure levels, the assembly condition at test bench is different than at engines. At engines, there is an additional assembly load coming from the screwing force of the injector at engine block. Finite element analyses were performed to verify the sealing at the interface where the micro leakage was identified, comparing both assembly conditions under normal working conditions and with higher loading levels, according to the applied at test bench. These studies show the possibility of leakage when assembled at test bench, due to the missing of injector assembly load and the higher applied internal pressure level. Therefore, it was validated the injector robustness when assembled at engines, even under higher pressure levels than normal working condition. Improvements at assembly conditions at test bench will be implemented in order to reduce the leakage possibility and to approximate the real assembly condition at engines.