Patent ID: 9644552
Date: 2017-05-09
CPC Classifications: F02D,F02M,F16K,F17C

Claim:
1. A method for a fuel system, comprising: responsive to a refueling request and prior to allowing access to a fuel filler neck, fluidly coupling a fuel tank to a fuel vapor canister by opening a valve; fluidly coupling the fuel vapor canister to atmosphere via a deactivated vacuum pump, where the fuel vapor canister is fluidly coupled to atmosphere via the deactivated vacuum pump further responsive to a fuel tank pressure above a first threshold; responsive to the fuel tank pressure decreasing below the first threshold, fluidly coupling the fuel vapor canister to atmosphere bypassing the deactivated vacuum pump, responsive to a fuel tank depressurization rate being less than a depressurization threshold, pulsing the changeover valve between the first conformation and the second conformation.