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LOW EVAPORATIVE EMISSION REFUELING METHOD FOR SADDLE TANKS

IP.com Disclosure Number: IPCOM000246980D
Publication Date: 2016-Jul-20
Document File: 1 page(s) / 199K

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The IP.com Prior Art Database

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LOW EVAPORATIVE EMISSION REFUELING METHOD FOR SADDLE TANKS

Most All Wheel Drive (AWD) vehicles have two fuel tanks connected to each other at the top due to packaging constraints around the AWD gear differential unit and shaft. These fuel tanks are called saddle tanks. Saddle tanks are typically positioned east-west in the rear of a car with one tank on driver side and the other on passenger side. The active side has a fuel pump, a filler neck and a Fuel Level Indication (FLI). The passive side only has a FLI without an active pump nor a filler neck.The active side is maintained full of fuel as a jet pump driven off the main electric pump siphons fuel from the passive side to the active side. This is how passive tank fuel is utilized. It must first go to the active side and from there it is pumped to the fuel rail and cylinders.The jet pump siphons the fuel using a simple Venturi effect device driven off the main active pump. In HEVs with saddle tanks, the fuel pump may be off for extended times if the car is driven in electric mode. Meanwhile, vehicle motion and dynamics may transfer fuel from the active side to the passive side. Since the main fuel pump is off in Electric drive mode (EV), this natural fuel transfer may result in emptying the active fuel tank. Even if vehicle is not a HEV, if prior to refueling a series of turns cause large amounts of fuel to migrate naturally from active to passive side and customer turns off the key, the passive side will have much more fuel than the active s...