| 摘要 |
When a tank filler tube cap (42) is closed, several flow paths having solenoid-operated valves are selectively operated by an engine management computer (16) to control pressurizing of a bladder (74) disposed in a fuel tank (12) and of surrounding fuel vapor space not occupied by the bladder to attenuate fuel vapor generation. Venting of the bladder to atmophere and of the vapor headspace (20) to a canister are also controlled. The control further regulates the pressure in the bladder relative to that in the vapor headspace. On-board testing for leakage can be automatically accomplished for ascertaining compliance with relevant regulations. When the tank is to be re-fueled, a signal is sent to the computer. If conditions, as sensed by certains sensors, are appropriate, the computer unlatches an access door (48) to the filler tube cap so that upon removal of the cap, no significant pressure differential that might cause vapor to be expelled from the tank to atmosphere, or impede the filling of the tank with fuel from the nozzle, is present. As liquid fuel is dispensed into the tank, the combined volume of the blader and the tank vapor headspace are reduced by the volume of liquid fuel introduced into the tank. The headspace cannot be repressurized until the cap again closes the filler tube.
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