The fuel injection rate

transient flow coefficient

fuel injection quantity etc. of each nozzle hole of diesel injector could be calculated by the measured fuel injection pressure and spray momentum flux of each nozzle hole. The fuel injection characteristics of each nozzle hole of four same size valve covered orifice (VCO) nozzles with the same model in a pump-pipe-injector fuel deliver system were measured and analyzed on a fuel injection pump tester with a data acquisition system. The results are as follows：for the same model of injector

the injection holes of different injectors and the various injection holes of the same injector have different injection characteristics. The transient flow coefficient of nozzle changes with time (pump cam angle) in the fuel injection process. The change tendency of flow coefficient of each nozzle hole in the same injector during the needle fully open is the same as that of the cycle injection quantity of each nozzle hole. The non-uniformity of fuel injection quantity and flow coefficient of each nozzle hole decreases with the increase of pump speed and fuel injection quantity. The non-uniformity of flow coefficient of each nozzle hole is less than that of fuel injection quantity. This means that the flow coefficient can not completely reflect the fuel injection characteristics of each nozzle hole.