International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

At the time of exploitation, the geometrical position of the control valve changes as a result of wearing, which leads to a change of residual electromagnetic gap stroke and force of control valve spring. The following study measures the hydraulic characteristic changes, based only on common rail injector increased stroke of control valve and residual electromagnetic gap. The results show that the increasing of control valve stroke and residual electromagnetic gap increase the fuel flow rate and return fuel flow. Increased fuel flow rate and return fuel flow are presented with short injector signal time and lower levels of working pressure. The increasing is lower with longer injector signal time and high level of working pressure. The follow-up results are practically significant by common rail electromagnetic injector diagnosing and repairing.

In the process of operation, there are changes in the injector with hydro-electromagnetic control of the nozzle needle. These changes are due to a wear on all components of the fuel system. Essential to the wear rate of the nozzle elements, excluding the clearing degree of the fuel and the extent of its cleaning prior to entering the high-pressure system of fuel system, are the operating pressure of the fuel, the number of sprays, the thermal load, the speed and the accelerations of the movable elements. The valve wear on the control valve changes the stroke of the ball valve. This variation results in an increase in the output flow from the control chamber, which increases the speed and the maximum stroke of the control piston and the flow fuel rate respectively. The ball valve stroke increasing respectively increases the distance between the core of the electromagnet and the coil. The increased distance between the coil and the core also has a significant effect on the hydraulic characteristics of the nozzle.