Fuel tank vent system and diaphragm valve for such system

• US 5,524,662 A
• Filed: 08/02/1994
• Issued: 06/11/1996
• Est. Priority Date: 01/25/1990
• Status: Expired due to Fees

• Current Assignee: GT Products, Inc. (Eaton Corporation PLC.)
• Original Assignee: GT Products, Inc. (Eaton Corporation PLC.)
• Inventors: Villemure, Matthew, Schwager, Bryce, Benjey, Robert P.
• Primary Examiner(s): Michalsky, Gerald A.
• Application Number:
  US08/284,264
• Time in Patent Office: 679 Days
• Field of Search: 137/43, 137/202, 137/587, 220/86.2, 220/746
• US Class Current: 137/43
• 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: Y10T 137/0874 Vent opening or closing on tipping container
• CPC Class Codes: Y10T 137/86324 Tank with gas vent and inlet or outlet

Abstract

A diaphragm-activated control valve and system for both refuel and running loss venting of a fuel tank to a vapor trap. The control valve is connected to fill control and rollover valves in the fuel tank, and defines a separate venting flow path for each valve to the vapor trap. The control valve is responsive to pressure conditions at the filler pipe inlet to alternately open and close the flow paths. During refueling the control valve vents the tank through the fuel-level responsive fill control valve. When the filler pipe inlet is closed, the control valve switches to vent the tank through the rollover valve. In a preferred form, the control valve includes a liquid fuel drain to prevent its being disabled by fuel entering from the filler pipe inlet via the signal pressure line during refueling. The drain includes a reverse flow check valve to prevent vapor venting out the drain path to the atmosphere during refueling.

Claims

1. In a vehicle fuel system of the type which includes a fuel tank, a filler pipe for admitting fuel to the tank, a selectively closeable filler pipe inlet and a vapor trap for collecting fuel vapor vented from the tank:

a vent valve connected between the tank and the vapor trap, having a first condition and a second condition, said vent valve including first means for placing said vent valve in the first condition when the filler pipe inlet is closed and second means for placing said vent valve in the second condition when the filler pipe inlet is open, a rollover valve connected between the tank and the vent valve and a fill control valve connected between the tank and the vent valve, the vent valve defining a first vapor flow path from the rollover valve to the vapor trap, and a second vapor flow path from the fill control valve to the vapor trap, further including means for opening the first vapor flow path and independently closing the second vapor flow path in the first condition, and means for closing the first vapor flow path and independently opening the second vapor flow path in the second condition.

2. A fuel system of the type including a fuel tank, a filler pipe for discharging fuel into the tank, a selectively closeable filler pipe inlet and a vapor trap for collecting fuel vapor vented from the tank, the fuel system further comprising:

a rollover valve disposed between the fuel tank and the vapor trap; and

a vent valve having a valve body, a vapor outlet to the vapor trap, and a vapor inlet from the rollover valve, a valve seat between the vapor inlet and the vapor outlet, a valve element matable with the valve seat, and a control element connected to the valve element for maintaining the valve element on the valve seal when the filler pipe inlet is at atmospheric pressure, and for displacing the valve element from the valve seat when the filler pipe inlet is at tank pressure, further including a fill control valve disposed between the fuel tank and the vapor trap, the vent valve including a second vapor inlet from the fill control valve and a second valve seat between the second vapor inlet and the vapor outlet, a second valve element matable with the second valve seat, and a second control element connected to the second valve element for displacing the second valve element from the second valve seat when the filler pipe inlet is at atmospheric pressure, and for maintaining the second valve element on the second valve seat when the filler pipe inlet is at tank pressure, wherein said first and second valve elements operate independently of each other.

3. A fuel system of the type including a fuel tank, a filler pipe for discharging fuel into the tank, a selectively closeable filler pipe arid a vapor trap for collecting fuel vapor vented from the fuel tank, the fuel system further comprising:

a rollover valve;

a vent valve;

means connecting the rollover valve and the vent valve in series between the tank and the vapor trap;

the vent valve having a valve body, a vapor outlet to the vapor trap, a filler pipe inlet, and a vapor inlet from the rollover valve, a first valve seat between the vapor inlet and the vapor outlet, a first valve element matable with the valve scat, and a first control element connected to the first valve element for maintaining the first valve element on the first valve seat when the filler pipe inlet is at atmospheric pressure, and for displacing the first valve element from the first valve seat when the filler pipe inlet is at tank pressure, further including a fill control valve and means connecting the fill control valve and the vent valve in series between the tank and the vapor trap, the vent valve further including a second vapor inlet from the fill control valve, a second valve seat between the second vapor inlet and the vapor outlet, a second valve element matable with the second valve seat, and a second control element connected to the second valve element for maintaining the second valve element on the second valve seat independently of the first valve element when the inlet from the filler pipe is at tank pressure, and for displacing the second valve element from the second valve seat independently of the first valve element when the inlet from the filler pipe is at atmospheric pressure, the vent valve connecting the rollover valve and the fill control valve in parallel.

4. A fuel system as defined in claim 3, wherein the vent valve further includes a second vapor inlet from the fill control valve, a second valve seat between the second vapor inlet and the vapor outlet, a second valve element matable with the second valve seat, and a second control element connected to the second valve element for displacing the second valve element from the second valve seat when the filler pipe inlet is at atmospheric pressure, and for maintaining the second valve element on the second valve seat when the filler pipe inlet is at tank pressure.

5. In combination with a fuel storage tank for a vehicle having a fuel vapor canister, a fuel system comprising:

a filler pipe having a selectively closeable inlet for discharging fuel into the fuel storage tank;

a rollover valve connected between the tank and the trap to vent the tank when the vehicle is in a normal attitude and to close the tank when the vehicle is not in a normal attitude;

a control valve in series with the rollover valve and operable between first arid second conditions; and

condition-responsive means for operating the control valve in response to the vapor pressure conditions near the filler pipe inlet, further including a fill control valve connected between the tank and the vapor trap to vent the tank when the liquid fuel level in the tank is below a predetermined maximum, the control valve connected in series with the fill control valve, the control valve including first means for venting fuel vapor from the rollover valve to the vapor trap in the first condition and second means for venting fuel vapor from the fill control valve to the vapor trap in the second position, said first and second means operating independently of one other.

6. A fuel system as defined in claim 5, the control valve further including means for shutting off venting from the fill control valve in the opened position, and means for shutting off venting from the rollover valve in the second position.

7. In combination with a fuel tank for a vehicle having a fuel vapor trap:

a rollover valve connected to the fuel tank;

a fuel-level responsive valve connected to the fuel tank;

a control valve connected to the rollover valve, the fuel level responsive valve and the vapor trap, the control valve defining a first vapor flow path between the rollover valve and the vapor trap, and a second vapor flow path between the fuel level responsive valve and the vapor trap; and

condition-responsive means for operating the control valve to alternately open and close the first and second flow paths the condition-responsive means including independent first and second valve elements.

8. A fuel system as defined in claim 7, further including a filler pipe for discharging fuel into the fuel tank and a selectively closeable filler pipe inlet, the condition-responsive means operating the control valve in response to pressure conditions near the filler pipe inlet.

9. A fuel system as defined in claim 8, wherein the condition-responsive means closes the first vapor flow path and opens the second vapor flow path when the filler pipe inlet is open, and opens the first vapor flow path and closes the second vapor flow path when the filler pipe inlet is closed.

10. A fuel system as defined in claim 9, wherein the condition-responsive means further comprise a first diaphragm for moving the first valve element on and off a first valve seat to close and open the first vapor flow path, and a second diaphragm for moving the second valve element on and off a second valve seat to close and open the second vapor flow path.

11. A fuel system as defined in claim 10, wherein the first diaphragm communicates with the filler pipe inlet on one side and the rollover valve on the other side, and the second diaphragm communicates with the filler pipe inlet on one side and the fill control valve on the other side.

12. A fuel system as defined in claim 11, wherein the first valve means communicates with the rollover valve on one side and with the vapor trap on the other side, and the second valve means communicates with the filler pipe inlet on one side and the vapor trap on the other side.

13. A fuel system as defined in claim 12, wherein the area of the first and second valve elements is less than-the area of the first and second diaphragms, respectively.

14. A fuel system as defined in claim 12, wherein the second valve element has a drain path formed therethrough communicating with the filler pipe inlet and the second vapor flow path.

15. A fuel system as defined in claim 14, wherein the drain path further includes means for preventing reverse fuel vapor flow from the fuel tank to the filler pipe inlet.

16. A fuel system as defined in claim 15, wherein the means for preventing reverse fuel vapor flow comprise a check valve in the drain path.

17. A fuel system as defined in claim 15, wherein the drain path communicates only with the fuel tank when the second valve element is in the closed position.

18. In combination with fuel tank for a vehicle having a fuel vapor trap:

a rollover valve connected to the fuel tank;

a fuel-level responsive valve connected to the fuel tank;

a control valve connected to the rollover valve, the fuel level responsive valve and the vapor trap, the control valve defining a first vapor flow path between the rollover valve and the vapor trap, and a second vapor flow path between the fuel level responsive valve and the vapor trap;

condition-responsive means for operating the control valve to alternately open and close the first and second flow paths;

a filler pipe for discharging fuel into the fuel tank and a selectively closeable filler pipe inlet, the condition-responsive means operating the control valve in response to pressure conditions near the filler pipe inlet;

wherein the condition-responsive means include drainage means between the filler pipe inlet and the second vapor flow path.

19. A fuel system as defined in claim 18, wherein the drainage means include means for preventing reverse flow of fuel vapor from the fuel tank to the filler pipe inlet through the drainage means.

20. A fuel system as defined in claim 19, wherein the means for preventing reverse vapor flow comprise a vapor-pressure operated check valve in the drainage means.

21. In a vehicle fuel system of the type which includes a fuel tank, a filler pipe for admitting fuel to the tank, a selectively closeable filler pipe inlet and a vapor trap for collecting fuel vapor vented from the tank;

a vent valve connected between the tank and the vapor trap said vent valve including first means for placing said vent valve in a first condition when the filler pipe inlet is closed and second means for placing said vent valve in a second condition when the filler pipe inlet is open, the vent valve comprising a valve body having a vapor inlet from the tank, a vapor outlet to the vapor trap, a valve seat between the inlet and outlet and a valve element biased toward and matable with said seat, said valve element being normally responsive to tank pressure to be displaced from said seat to provide vapor venting from the tank to the trap;

a control element connected to the valve element and responsive to the net of atmospheric pressure in the filler pipe inlet and vapor pressure in the tank to maintain the valve element on said seat;

drainage means formed in the valve element to permit liquid fuel to drain through the valve element regardless of the position of the valve element on the valve seat, the drainage means comprising a drain path formed in the valve element communicating with the filler pipe inlet and the fuel tank, the drainage means further including check valve means in the drain path for preventing reverse flow of fuel vapor from the fuel tank to the filler pipe inlet.

22. For use in a vehicle fuel system of the type which includes a fuel tank, a filler pipe for admitting fuel to the tank, a selectively closeable filler pipe inlet, a vapor trap for collecting fuel vapor vented from the tank, a rollover valve associated with the tank and a fill control valve associated with the tank, a vapor venting control valve comprising:

a valve body having a vapor inlet from the filler pipe, a vapor inlet from the rollover valve, a vapor inlet from the fill control valve, and a vapor outlet to the canister;

first and second diaphragm-operated valve elements comprising a diaphragm control element and a valve member;

a pressure chamber defined between the diaphragms of the first and second valve elements, the pressure chamber connected to the vapor inlet from the filler pipe, the first and second valve elements being pressure balanced such that higher vapor pressure in the pressure chamber forces the valve elements in opposite directions to open a rollover venting path associated with the first valve element and to simultaneously close a fill control venting path associated with the second valve element, and lower pressure in the pressure chamber when the filler pipe inlet is open forces the first and second valve elements toward one another to close the rollover venting path and open the fill control venting path.