| 摘要 |
A fuel cap having a pressure-vacuum valve assembly for sealing a vehicle fuel tank is provided. The cap has a normally closed vent to vent the fuel tank, with a first valve member to open the vent when the pressure within the tank reaches a predetermined superatmospheric level. The cap also has a second valve member to open the vent when the pressure within the tank reaches a predetermined subatmospheric level. The cap includes a roll-over valve disposed above the first and second valve members to close the vent when the vehicle and cap are rolled over to a substantially inverted orientation to prevent fuel from spilling out of the cap. |
