Fuel tank pressure-vacuum relief valve

• US 4,040,404 A
• Filed: 01/19/1976
• Issued: 08/09/1977
• Est. Priority Date: 02/17/1973
• Status: Expired due to Term

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Tagawa, Katsuhiro
• Primary Examiner(s): Dority, Jr., Carroll B.
• Assistant Examiner(s): Devinsky, Paul
• Application Number:
  US05/650,153
• Time in Patent Office: 568 Days
• Field of Search: 123/136, 137/493, 137/493.8, 137/493.1
• US Class Current: 123/519
• CPC Class Codes: B60K 15/03519 Valve arrangements in the vent line
• CPC Class Codes: F02M 25/0836 Arrangement of valves controlling the admission of fuel vapour to an engine, e.g. valve being disposed between fuel tank or absorption canister and intake manifold
• CPC Class Codes: F16K 15/14 with flexible valve members
• CPC Class Codes: F16K 17/19 Equalising valves predominantly for tanks when combined with safety valve by change of position F16K17/36
• CPC Class Codes: F16K 17/196 spring-loaded
• CPC Class Codes: Y10T 137/7773 Supporting valve only spring biased
• CPC Class Codes: Y10T 137/7774 Supporting valve spring carried by supporting valve

Abstract

Two check valves are connected between a fuel tank and a carbon canister to relieve excessive pressure or vacuum in the fuel tank.

Claims

1. A pressure relief valve for a fuel tank of a motor vehicle equipped with an evaporative emission control system, said valve comprising:

a cylindrical hollow casing having end portions said end portions being closed and having an inlet and outlet at said both end portions, respectively, said inlet communicating with the fuel tank and said outlet communicating with the atmosphere;

a cylindrical movable valve element coaxially disposed within said cylindrical hollow casing and being in spaced relationship thereto and also in spaced relationship with said both end portions, said cylindrical movable valve element including a cylindrical wall portion, and an annular partition wall portion which is integral with the inner surface of the cylindrical wall portion adjacent one end of said cylindrical movable valve element, the one end being adjacent to one hollow casing end portion having the outlet, the annular partition wall portion having at least one radially outward hole therethrough;

a compression spring interposed between the inner surface of the one hollow casing end portion having the outlet and the annular partition wall portion of said cylindrical movable valve element to bias said cylindrical movable valve element in the direction of another hollow casing end portion having the inlet;

an annular resilient valve member mounted at its central portion on the annular partition wall portion of said cylindrical movable valve element, said annular resilient valve member having at its peripheral portion a flexible flap portion which is located opposite said compression spring with respect to the annular partition wall portion, the flexible flap portion normally urgingly closing the hole of the annular partition wall portion and opening the hole to introduce atmospheric air therethrough from the outlet of said cylindrical hollow casing to the inlet of said cylindrical hollow casing when fuel vapor pressure in the fuel tank drops bellow zero gage pressure; and

a cylindrical resilient valve member securely mounted on the another end of said cylindrical movable valve element adjacent to the inlet of said cylindrical hollow casing, said cylindrical resilient valve member being formed with a central bore therethrough and an annular lip portion which is normally urged by said compression spring into sealingly contact with the inner surface of the another hollow casing end portion having the inlet, said cylindrical resilient movable valve member being moved to a position which unseats the lip portion from the inner surface so as to introduce fuel vapor from the fuel tank through the inlet of said cylindrical hollow casing and around said cylindrical movable valve element to the outlet of said cylindrical hollow casing when the fuel vapor pressure in the fuel tank exceeds a predetermined value.

2. A valve as claimed in claim 1, in which the evaporative emission control system includes a fuel storage unit communicable with the fuel tank and the atmosphere, said valve being connected between the fuel vapor storage unit and the fuel tank.

3. A valve as claimed in claim 2, in which the fuel vapor storage unit is a carbon canister.