The effect of length of high pressure pipes on injection process in common rail system of diesel engine

The storage supply systems of Common Rail type are characterized by high possibilities in shaping the rate of injection. The possibility to implement multi-injection at high pressure, easiness of adapting the system to the engine, relatively easiness of compensation the arrangement of injector parameters resulting from work tolerance, as well as easiness of making changes in the electronic engine controller enabling the production of engines with various performances, cause that type of these solutions currently are widely used injection systems in diesel engines. Injection system should be characterized above all by high precision fuel dosing into engine cylinders, the accuracy in starts controlling of individual phase of injection, repeatability and reliability and durability, as well as the up keep of these parameters for long time during operating duration. Fuel injection system works in difficult conditions resulting from high pressure, vibrations, electromagnetic interference affecting electronic executive systems and high temperatures. Especially the injector and injection pipes are open to high temperatures. The dimensions of used elements are also important. The article presents selected results concerning the effect of the length of high-pressure pipes on injection process parameters such as fuel amount, overflow in injector, and the fuel pressure course in injection pipe in front of electromagnetic injector socket. The study was conducted with test stand with electronic measurement system of fuel amount. The tests were made at different pressures in the rail and for different durations of the injector opening.