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This paper presents an experimental study of the correlation between rail-to-injector connection pipe geometry (3 lengths and 3 diameters) and pressure oscillation characteristics (amplitudes, mean pressure drop, frequency, damping of the oscillation) and injected volume, respectively. The injection input parameters are based on a single injection with 5 pressure levels and 4 injection durations. Pressure recordings are available for the injector inlet, an adjacent injector port, and the rail. The study shows that the connection pipe geometry may have a considerable impact on the analyzed variables. Particularly interesting appears the unexpected bond between pipe diameter and oscillation frequency.

This paper investigates the source of pressure fluctuations in a common rail (CR) system for high speed diesel engines as a function of injection parameters and system design (pipe between rail and injector). The pressure values are recorded experimentally at the inlet of the injector. In addition, a simulation model has been developed. The parameters include: injection pressure (800 to 1500 bar) and duration (0.4 to 1 ms), and connection pipe length (180 to 500 mm) and diameter (2.2 to 3 mm). The model shows good agreement with the measurements. The study shows that all parameters have an effect on the pressure oscillation at the injector inlet.