Department of diesel fuel in the three dual cases, the fuel injector nozzle couplings have a special detector to test its performance, fuel Plunger pump by rotating camshaft (high-pressure tubing and nozzle connected) and with feeling Couples can know good and bad, without disintegration testing, only the valve can not be detected in the pump test schools, generally only test the opening pressure of school, as its one-way sealing, vacuum sealing ring can not be tested by this to the fuel system fault diagnosis and repair work to bring many difficulties.
Repair oil pump in the school often have customers tell their gross engine work, speed instability and low Knocking sound serious, but the injector well and the other part of the normal diesel engine, which suspected the problem of high pressure oil pump repair. When the oil pumps in the inspection time, governor, oil sealing plunger, delivery valve opening pressure were normal, the plunger set screws and locking plunger adjustment screw ring gear and the oil valve seat are not loose, but individual cylinder fuel are high. If the high-cylinder fuel transferred to normal, often malfunction persists. If the adjustment in the fuel oil before the oil valve cylinder high renewal,
The fault can be all removed, why?
As everyone knows, the oil valve is a one-way valve, whose role is to guarantee a certain pressure of diesel into the high-pressure pipeline when, at the same time prevent the high-pressure diesel fuel injection pump flows down from the high-pressure pipeline and oil in each end, the reduction pressure zone can be rapidly within the high pressure oil diesel oil pressure decreases, the injector after the rapid drop off oil to prevent. If a decompression valve and valve seat ring with the gap is too large, then the decompression effects of variation, high-pressure tubing higher than normal residual pressure. Thus, when a total of plunger upward pressure oil, the oil valve to increase the one hand,
On the other hand diesel across the vacuum valve seat ring and the oil is too large gap between the top open cone directly into high-pressure pipeline, which in fact is equivalent to advance the start of oil. If we debug the corresponding pump cylinder when the fuel supply only a small adjustment, although it solves the problem of uneven fuel tank, but the original oil tank is still the high side than the other oil tanks in advance, so engine failure can not be completely resolved, thus see that the oil valve on the test room is necessary.
Because we in the diagnosis of fuel system failure, not only the sights on the governor and the oil plunger and the nozzle on the pump at the repair school, be sure to pay attention to check the quality of the oil valve, otherwise the problem complicated, or even resolve. However, check out the current lack of quality valve equipment, repair shop received multiple high-pressure tubing connector with a pressure gauge to check the quality of the plunger valve while checking out the quality, but can only test a valve cone seal, and can not Measurement know these decompression valve seat ring and matching quality. To this end, we trial a simple and practical tool for quality inspection of the oil valve,
Convenient to bring a lot of maintenance work, are recommended as follows. Use, first the valve mount fixtures, fittings and then a nozzle test device with the tubing connected with the establishment of hydraulic injector tester can. According to our experience of using the service to require:
Taper sealing: Pressure from the time of not less than 1.5MPa 21MPa down to 50s, or need to grind sealing cone.
Decompression ring seal performance: first, screw the outlet valve from the valve seat top from 0.3mm, the pressure decreased from 21MPa 2MPa time not less than 3s, or scrapped.