| 摘要 |
A combination vent valve/purge valve apparatus (10) for an automotive fuel vapor recovery system canister (14) comprises a purge valve (26) and a vent valve (16) in a single housing. When open, the vent valve (16) allows outside air to enter the canister (14). The purge valve (26), when open, allows fuel vapor to flow from the canister (14) into a vacuum source (12). A gas channel (28, 130, 168) extends between a vent chamber (18) within the vent valve (16) and a purge chamber (28) within the purge valve (26). When the purge valve (26) is open and a purge plunger (86) within the purge chamber (28) is positioned away from the gas channel (28, 130, 168), the manifold vacuum draws air from one side of a diaphragm (126) within the vent chamber (18) drawing the diaphragm (126) and a vent plunger (152) downward against a spring to close the vent valve (16). When the purge plunger (86) is positioned to block the gas channel (28, 130, 168), the spring forces the vent plunger (152) upward to open the vent valve (16). Therefore, a single actuator (36) is able to directly control purge closure position and to indirectly control vent closure position to either purge the canister (14) or evacuate the canister (14) to prepare for a leak check.
|
