Main role of fuel rail for GDI(Gasoline Direct Injection) system is to store and distribute gasoline between high pressure pump and injector. Under the engine operating condition, fuel pressure and ambient temperature are applied to fuel rail as fatigue load, which can cause fatigue fracture. Accordingly, fatigue behaviors of fuel rail must be analyzed at the development stage.
In this study, fatigue life estimating process was developed. With this, fatigue load on the GDI fuel rail can be expected under actual vehicle operating conditions. Furthermore, fatigue life of a part can be verified based on the expected fatigue load. To establish certain process, pressure and temperature on fuel rail were measured under real car condition. Afterwards, measured data was extrapolated to product warranty with probabilistic method and damage model specified. By applying obtained result, fatigue test mode was designed for fuel rail reliability target.