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A METHOD TO ELIMINATE PASSIVE VALVES IN NIRCOS SEALED TANKS

IP.com Disclosure Number: IPCOM000240487D
Publication Date: 2015-Feb-03
Document File: 1 page(s) / 247K

Publishing Venue

The IP.com Prior Art Database

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A METHOD TO ELIMINATE PASSIVE VALVES IN NIRCOS SEALED TANKS

HEV vehicles have a sealed fuel tank. HEV Evap system is called NIRCOS (Non Integrated Refueling Canister Only System).The sealed fuel tank is required since HEV engine run time is limited. Hence, diurnal and running loss vapors cannot be allowed to load the canister. Only refueling vapors can load the canister.NIRCOS fuel tanks are typically made of steel and designed to withstand extreme pressure and vacuum magnitudes from diurnal temperature swings. FirstGen NIRCOS is comprised of a solenoid valve (FTIV) that is normally closed between the fuel tank and carbon canister. Fuel tanks are also typically equipped with passive valves FLVV (Fuel Fill Limit Valve) and GVV (Grade Vent Valves). FLVV is used to shut off the dispensing valve during refueling. The GVV is needed to prevent fuel carryover into the Evap vapor lines when parking on inclines.

Method

This design centers around cost reducing the NIRCOS Evap system. Since the NIRCOS system includes essentially an active electromechanical valve and a passive valve (GVV, FLVV) in series, an opportunity exists to cost reduce the design by eliminating the passive valves (GVV and FLVV). The purpose of the FLVV is to shutoff the dispensing pump when fuel reaches 100% level during refueling. In a PHEV, the PCM is typically alive during refueling, as the fuel tank must first be vented. A button on the dash wakes up the PCM to request refueling. Once the fuel...