Controlling vapor emission in a small engine fuel tank system
AssigneeVaughn K. Mills
InventorVaughn Mills
Life of this patent
Estimating the term…
Abstract
A fuel vapor emission system for small engine gas tank which does not require redesign or retooling for manufacturing of the tank. A new filler tube has the lower end positioned to cause fuel to rise rapidly in the tube before the tank is full, signaling the operator to stop refueling and maintain a vapor dome in the tank when the filler cap is replaced. A vapor vent valve is disposed in a separate access opening and includes a float operated rollover valve. The vent valve opens when a predetermined positive pressure is reached in the tank; and, a reverse flow vacuum relief valve is disposed in the vent valve. The outlet of the vent valve is intended to be connected to either a storage canister or the engine air inlet.
Claims25
A small engine fuel tank vapor emission control system comprising:
- a fuel tank for use with a small engine;
- a vapor vent valve disposed to receive vapor from within the tank and including a vent outlet, wherein the vapor vent valve closes the vent outlet when the fuel level rises to a predetermined level in the tank;
- a filler tube disposed through a wall of the tank;
- a fill level device that responds to liquid fuel rising in the tank during refueling to define a vapor dome in the tank;
- and,
- a normally closed check valve disposed to block vapor flow in said vent outlet and operable to open at a predetermined vapor pressure in the tank.
A method of controlling vapor emission from a small engine fuel tank comprising:
- forming a fuel tank;
- disposing a vapor vent valve for communicating fuel vapor in the tank from the valve outlet to a canister and closing the vent valve when fuel in the tank reaches a predetermined level;
- disposing a fill level device through a wall in the fuel tank and locating the fill level device to respond to liquid fuel rising in the tank to define a vapor dome in the tank;
- and,
- disposing a normally closed check valve in the valve outlet of the vent valve to prevent vapor flow to one of a canister and an engine air inlet until the vapor pressure reaches a predetermined level above atmospheric pressure.
A method of controlling venting of fuel vapor in a small engine fuel tank comprising:
- disposing a filler tube through a wall of the tank and extending one end of the tube to a desired level of fuel fill in the tank;
- disposing a float operated vent valve in the tank, wherein the vent valve vents vapor and closes in response to a rising fuel level, and wherein a vapor outlet of the vent valve is connected to at least one of a storage canister an engine air inlet;
- and,
- disposing a check valve in the vapor outlet of said vent valve to block flow therethrough at vapor pressures less than a predetermined minimum level above atmospheric pressure.
A system for maintaining a vapor dome in a small engine fuel tank connected to a vapor storage device comprising:
- (a) a filler tube with one end extending to a predetermined level in the tank, wherein the filler tube is closable by a user operable closure on an end of the filler tube communicating exteriorly of the tank;
- (b) a conduit defining a vapor vent path from the tank to the vapor storage device;
- (c) a pressure responsive valve disposed in the vapor vent path and operable to substantially prevent vapor flow when vapor pressure in the tank remains below a predetermined threshold and to substantially permit vapor flow to the vapor storage device when the vapor pressure in the tank reaches the threshold, wherein upon removal of said closure and refueling through said tube, fuel reaching the predetermined level causes fuel to reach different levels in the filler tube and in the tank to provide visual notice of the fill level and preserve a vapor dome in the tank.
A method of controlling fuel vapor emission in a small engine fuel system comprising:
- (a) disposing a filler tube on the tank with an operable closure on one end and locating the end opposite said one end at a predetermined fill level in the tank such that, upon reaching said predetermined fuel level, the fuel in the filler tube rises at a different level than the fuel in the tank, thereby forming a vapor dome in the tank;
- (b) forming a vapor vent flow path from the interior of the tank to the exterior thereof;
- and,
- (c) disposing a normally closed pressure responsive valve in said vent path and opening the valve when the vapor pressure in the tank reaches a predetermined level.
Dependencies are inferred from the claim text.