Comparative tests of diesel injectors with current and upgraded nozzles

Abstract

BACKGROUND: More than 60% of agricultural tractor failures are due to diesel engine failure. Half of diesel engine failures relate to the fuel supply system, which is mainly dependent on the service life of diesel injectors’ nozzles. AIM: Increasing the durability of the nozzle by means of upgrading the nozzle needle. METHODS: To increase the working life of the diesel injector nozzle, a new technical solution, the idea of which is applying a screw channel to the bearing surface of the needle, was proposed. The presence of the screw channel leads to axisymmetric pressure on the needle, which gives it increased stability and prevents the possibility of skewing and freezing. The Russian patent has been received for this invention. To confirm the expected effect, comparative laboratory tests were carried out with current and upgraded nozzle design. To carry out accelerated tests, the “dusty” fuel, obtained by adding quartz sand abrasive, was used. During the tests, the following were assessed: atomization quality, sealing cone tightness, hydraulic density, needle stroke and effective flow area. The assessment of wear of the mating surfaces of the nozzle depends on the value of the hydraulic density. RESULTS: As a result of the experiment, it was found that the limiting value of hydraulic density for the current injectors occurs after 2500 operating hours and is characterized by a violation of tightness. For the upgraded injectors, the hydraulic density limit occurs after 4300 operating hours. CONCLUSION: Applying a screw channel on the bearing surface of the needle helps to increase the service life of the diesel injector by 23%.