Fuel Tank System Design Consideration with Low Fuel Filling Circuit Position in Automotive Vehicle

Liquid fuel storage system stores the fuel to facilitate vehicle running for desired range. Fuel system being a safety critical component is designed to endure varied environmental condition and defined robustness for all usage conditions. Liquid fuel system consists of three major systems viz. filling system, storage system and vapor management system. Of the three, filling system’s major function is to assist proper re-fueling of the storage system. Pre-mature shut-off, spillage and fuel spit back are the three major risks associated to judge system performance. In general, fuel filling system is connected to fuel tank via inlet pipe which houses a flapper to avoid fuel spillage from filler neck. Fuel filling creates positive pressure inside the tank which causes tank to bulge. In process of regaining the shape fuel is pushed out of the inlet pipe to neck which might cause spillage. A one-way valve mechanism (flapper) is added to restrict fuel spillage. In models where fuel neck height is very low wrt fuel tank breathing port position, addition of flapper causes hinderance in fuel filling. This paper addresses the root cause analysis of the problem and counter measure action plan. Keywords: Pre-mature shut-off, spillage, fuel spit back, flapper, breathing port