Experimental Study of the Hydraulic Circuit of a Commercial Common Rail Diesel Fuel Injection System

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.