Improving the damaged surfaces due to particle erosion by pre-forming process to be applied to the valve seat surface in solenoid diesel injector

Common-Rail system is the most used injection technology in modern diesel engines. One of the most important parts of this system is the injectors that inject fuel with a pressure up to 2500 bars into the combustion chamber. The most used injector type in this fuel system is diesel injectors with solenoid valves controlled by electro valves. The balance of forces around control volume of valve provides control of the solenoid valve. Fuel is injected into the combustion chamber by opening or closing the solenoid valve with the current from the Electronic Control Unit (ECU). This cycle is repeated millions of times over the life of the injector. As a result of this cycle repeated over and over at high pressure, the injector valve may wear out due to solid particles in the fuel and may cause the valves to leak. Thus, differences in injection characteristics and engine emission values can occur. In a study conducted by the Bosch development department, the injectors which have coated and worn valve bodies were subjected to a second endurance test. As a result of this test, the cleanliness of the injector had not changed. Accordingly, it has been interpreted that this wear geometry may be an alternative to coating application on valve bodies. In this thesis, the deformation of the surface by applying force with a spherical profile to the ball seating surface of uncoated valve parts in zero-kilometre diesel injectors and its effect on the performance of the valve part were investigated. In this context, a computer-aided simulation study was carried out to examine the functional behaviour of the valve. Based on the simulation study result, test studies were completed to examine the particle and cavitation behaviour.