Fuel tank vent system and diaphragm valve for such system

Claim 2

In a vehicle fuel system of the type which includes a fuel tank, a filler pipe having an inlet opening for admitting fuel to the tank, a cap for closing the outer end of the filler pipe inlet opening and a vapor trap for collecting fuel vapor vented from the tank, the fuel system further comprising: a vent valve connected between the tank and the vapor trap and having an open condition and a closed condition; said vent valve including first means for placing said valve in an open, venting condition when the outer end of the filler pipe inlet opening is closed; and second means for placing said valve in a closed, non-venting position when the outer end of the filler pipe inlet opening is open.

Claim 3

Apparatus as defined in claim 1 wherein the vent valve comprises: 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; and a control element connected to the valve element for maintaining the valve element on said seat when the filler pipe inlet is at atmospheric pressure.

Claim 4

Apparatus as defined in claim 2 wherein the control element is a diaphragm sealed in said body, means communicating one side of the diaphragm to the filler pipe inlet; and means communicating the other side of the diaphragm to the tank.

Claim 5

Apparatus as defined in claim 1 further including a rollover valve connected between the tank and the vent valve.

Claim 6

Apparatus as defined in claim 1 wherein said first means includes a vapor vent line from said vent valve to the fuel tank; and said second means includes a vapor pressure line from said filler pipe to said vent valve.

Claim 7

A fuel system of the type including a fuel tank, a filler pipe for discharging fuel into the tank, a cap for closing the filler pipe inlet and a vapor trap for collecting fuel vapor vented from the fuel 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 seat 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.

Claim 8

A fuel system of the type including a fuel tank, a filler pipe for discharging fuel into the tank, a cap for closing the filler pipe inlet and a vapor trap for collecting fuel vapor vented from the fuel 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 seat 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.

Claim 9

A fuel system as in claim 6 wherein the control element is a diaphragm.

Claim 10

A fuel system as in claim 6 wherein the valve element is biased towards said seat by a spring.

Claim 11

A fuel system of the type including a fuel tank, a filler pipe for discharging fuel into the tank, a cap for closing the filler pipe inlet and a vapor trap for collecting fuel vapor vented from the fuel tank, the fuel system further comprising; a tank vent valve comprising a valve body defining an interior chamber, an inlet connected to the tank and communicating with said chamber, an outlet connected to a vapor trap communicating with said chamber, a valve seat within said chamber and between said inlet and said outlet, a valve element movable within said chamber into and out of engagement with said seat to control communication between said inlet and said outlet, a control element sealingly disposed within and across said chamber to separate said chamber into a first side which is in constant communication with said tank by way of said inlet, and a second side having a second inlet connected in fluent communication with a tank filler pipe effectively proximate the inlet opening thereof; said control element being mechanically connected to the valve element to urge the valve element positively into engagement with the seat when tank pressure substantially exceeds the pressure adjacent the tank filler pipe opening.

Claim 12

A fuel system of the type including a fuel tank, a filler pipe for discharging fuel into the tank, a cap for closing the filler pipe inlet and a vapor trap for collecting fuel vapor vented from the fuel tank, the fuel system further comprising; a tank vent valve comprising a valve body defining an interior chamber, an inlet connected to the tank and communicating with said chamber, an outlet connected to a vapor trap communicating with said chamber, a valve seat within said chamber and between said inlet and said outlet, a valve element movable within said chamber into and out of engagement with said seat to control communication between said inlet and said outlet, a control element sealingly disposed within and across said chamber to separate said chamber into a first side which is in constant communication with said tank by way of said inlet, and a second side having a second inlet connected in fluent communication with a tank filler pipe effectively proximate the inlet opening thereof; said control element being mechanically connected to the valve element to urge the valve element positively into engagement with the seat when tank pressure substantially exceeds the pressure adjacent the tank filler pipe opening.

Claim 13

Apparatus as defined in claim 9, wherein the control element comprises a flexible diaphragm.

Claim 14

Apparatus as defined in claim 10, wherein the effective area of the diaphragm is larger than the effective area of the seat to maintain positive closure at all pressures.

Claim 15

A fuel system of the type including a fuel tank, a filler pipe for discharging fuel into the tank, a cap for closing the filler pipe inlet and 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; and the vent valve having a valve body, a vapor outlet to the vapor trap, and a vapor inlet from the rollover valve, the 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 seat 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.

Claim 16

A fuel system of the type including a fuel tank, a filler pipe for discharging fuel into the tank, a cap for closing the filler pipe inlet and 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; and the vent valve having a valve body, a vapor outlet to the vapor trap, and a vapor inlet from the rollover valve, the 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 seat 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.

Claim 17

A fuel system as claimed in claim 12 wherein the valve element is biased toward said seat by a spring.

Claim 18

In a vehicle fuel system of the type which includes a fuel tank, a filler pipe having an inlet opening for admitting fuel to the tank, a cap for closing the inlet opening of the filler pipe and a vapor trap for collecting fuel vapor vented from the tank; a venting system comprising: a partition means dividing the filler neck into an outer chamber communicable with the inlet opening and an inner chamber communicable with the fuel tank; a vent valve connected between the tank and the vapor trap having an open, venting position and a closed, non-venting position; means for opening said vent valve when the pressure in the outer chamber is substantially equal to tank pressure; and means for closing said vent valve when the pressure in the outer chamber is at substantially atmospheric pressure.

Claim 19

In a vehicle fuel system of the type which includes a fuel tank, a filler pipe having an inlet opening for admitting fuel to the tank, a cap for closing the inlet opening of the filler pipe and a vapor trap for collecting fuel vapor vented from the tank; a venting system comprising: a partition means dividing the filler neck into an outer chamber communicable with the inlet opening and an inner chamber communicable with the fuel tank; a vent valve connected between the tank and the vapor trap having an open, venting position and a closed, non-venting position; means for opening said vent valve when the pressure in the outer chamber is substantially equal to tank pressure; and means for closing said vent valve when the pressure in the outer chamber is at substantially atmospheric pressure.

Claim 20

Apparatus as defined in claim 14 wherein the vent valve comprises: a valve body having a vapor inlet from the tank, a vapor outlet to the vapor trap, a valve seat between the inlet and the 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; and a control element connected to the outer chamber and responsive to a pressure differential between the inner chamber and outer chamber to maintain the valve element on the seat.

Claim 21

An apparatus as defined in claim 15 wherein the control element is a diaphragm sealed in said body, means communicating one side of the diaphragm to the other chamber; and means communicating the other side of the diaphragm to the inner chamber.

Claim 22

In combination with a fuel storage tank for a vehicle having a fuel vapor trap; a fuel system comprising: a filler pipe having a selectively closeable inlet for discharged 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 opened and closed positions; and condition-responsive means for operating the control valve in response to vapor pressure conditions near the filler pipe inlet.

Claim 23

In combination with a fuel storage tank for a vehicle having a fuel vapor trap; a fuel system comprising: a filler pipe having a selectively closeable inlet for discharged 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 opened and closed positions; and condition-responsive means for operating the control valve in response to vapor pressure conditions near the filler pipe inlet.

Claim 24

In a vehicle fuel system of the type which includes a fuel tank, a filler pipe for admitting fuel to the tank, a cap for closing the 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 and having an open condition and a closed condition; said vent valve including first means for opening said vent valve when the filler pipe inlet is closed; and second means for closing said vent valve when the filler pipe inlet is open.

Claim 25

In a vehicle fuel system of the type which includes a fuel tank, a filler pipe for admitting fuel to the tank, a cap for closing the 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 and having an open condition and a closed condition; said vent valve including first means for opening said vent valve when the filler pipe inlet is closed; and second means for closing said vent valve when the filler pipe inlet is open.

Claim 26

Apparatus as defined in claim 18, wherein the vent valve remains closed when the filler pipe inlet is open and fuel is being admitted to the fuel tank.