摘要 |
<p>FUEL TANK VAPOR FLOW CONTROL VALVE -- -- In an evaporative emission control system for a vehicle, the flow of fuel vapor from the fuel tank to the vapor storage canister in the system is controlled by a vapor flow control valve having a housing with a chamber therein in flow communication with the fuel tank to receive fuel vapor therefrom this chamber being connected to the vapor storage canister by a first vapor passage means and by a second vapor passage means, with flow from the chamber through the first vapor passage means being controlled by a diaphragm valve means that is normally biased closed by a spring, and which is responsive to either engine vacuum on one side thereof or to a predetermined fuel vapor pressure on its opposite side whereby to permit vapor flow and, the second vapor passage means including a sized bleed orifice passage used to control the rate of vapor flow to the storage canister via this second vapor passage means.</p> |