Electronic Refueling and Vent Control System with Integrated Control
A modification to the vent control system of a fluid tank is provided. More particularly, an electronically controlled vent control system used in connection with a fuel tank is provided. The vent control system disclosed is operable to automatically sense the beginning of a fueling event and to open a venting valve allowing fuel to enter the tank. Subsequently, as the fuel reaches a predetermined fill level, the vent control system is operable to automatically close the venting valve, halting the flow of fuel into the tank.
The invention relates to a vent control system used in connection with fluid tanks, and more particularly, to an electronically controlled vent control system used in connection with a fuel tank. The vent control system disclosed is operable to automatically sense the beginning of a fueling event and to open a venting valve allowing fuel to enter the tank. Subsequently, as the fuel reaches a predetermined fill level, the vent control system is operable to automatically close the venting valve, halting the flow of fuel into the tank.DESCRIPTION OF RELATED ART
The present invention relates to filling of fluid tanks, and more particularly to the venting of gasses or vapors in those tanks during the filling process. In general, these systems are known as Onboard Refueling Vapor Recovery (ORVR) systems. Typically, as a fluid enters a tank, it must displace the gas or vapor already in the tank. Depending on the fluid in the tank, such gas or vapor may be a benign substance such as air. However, in the case of volatile fluids such as gasoline which give off vapor, the release of this vapor must be controlled so as to prevent the release of harmful substances. In some systems, the venting of this vapor is trivial as the gas is allowed to escape through the fill point, or the tank may include a manually operated vent. However, in certain applications, such as the filling of a fuel tank, it is desirable that venting be controlled so that environmentally harmful fuel vapor is not released into the atmosphere. In these applications, fuel filler nozzles and fuel tank filler tubes have been designed to create a liquid or vapor seal between the nozzle and tube preventing the release of vapor through that outlet. As a result, a separate vent must be created that will allow the venting of vapor while retaining hydrocarbons, usually in a carbon charged filter canister.
Furthermore, it is known to use filler nozzles which are operable to automatically shut off when a certain level of back pressure within the tank being filled is reached. This design allows for the automatic filling of a tank while lessening the risk of an undesirable over-fill and spill. It is also known to utilize the vapor vent in connection with this automatic shut-off technology. Specifically, by closing the vapor vent it is possible to increase the pressure within the tank, causing the filler nozzle to shut off.
Finally, in applications in which the tank is a fuel tank in a vehicle, it is desirable to include additional safeguards to prevent the release of fuel in the event of a vehicle roll-over. Thus, for each of the reasons, it is desirable to have advanced refueling and venting systems capable of automatically controlling the opening and closing of one or more vapor vents.
Prior to the present invention, various refueling systems have been disclosed to control the flow of fuel into a fuel tank and the associated release of vapor out of the tank. U.S. Pat. No. 6,601,617, issued Aug. 5, 2003, to Enge, and U.S. Pat. No. 5,687,762 issued Nov. 18, 1997 to Teets, et al, are illustrative. While these patents disclose certain elements of automatic venting systems, the present invention provides an improvement in that it provides integrated electronic control of the opening and closing of the vent valve. This electronic control provides more precise opening and closing of the valve, reducing the amount of vapor allowed to escape from the tank. Furthermore, with the exception of an electrical connection to the vehicle battery to supply power, the present invention provides a self-contained system that operates free from other electrical systems that may be present depending on the application. For example, if the fluid tank were a fuel tank installed on a passenger vehicle, there may be an engine control or powertrain control module associated with that vehicle. Existing systems tie into these controls, occupying physical space and using processing power. The present invention is able to operate independently of these controls, freeing space and processing power on the engine or powertrain control modules.
Thus, it is an object of the present invention to provide a vent control system capable of automatically opening a vapor vent in response to a refueling event.
It is a further object of the present invention to provide an electronically controlled vent control system operable for use in connection with a fuel tank of a vehicle which, with the exception of a power connection, is self contained.SUMMARY OF THE INVENTION
The present invention is drawn to a new and improved electronically controlled vent control system. While the present invention may find greatest application in connection with the fuel tanks of vehicles, and the various examples herein are described in relation to vehicles, it is applicable to other fluid tanks which have a need for controlled venting of vapors from the tank. The apparatus of the present invention includes a sensor operable to detect the beginning of a refueling event, a sensor operable to detect when a predetermined fill level within the tank has been reached, an electronic control apparatus operable to send a signal once a refueling event has been detected and when the predetermined fill level has been reached, and a vent valve operable to open and close in response to signals received from the electronic control apparatus.
When in operation, the apparatus first detects the beginning of a refueling event by detecting the presence of a fill nozzle being inserted into a filler tube. When a fill nozzle is detected, a signal is sent to the vent valve causing it to open. With the vent valve open, pressure is released from the tank, allowing fuel to be introduced. As the fuel is introduced, a passive fill level sensor monitors the level of fuel in the tank. Once a predetermined level of fuel within the tank has been reached, the level sensor sends a signal to the vent valve causing it to close. By closing the vent valve, the system causes pressure in the tank to rise. The increased pressure causes the fill nozzle to automatically shut off, completing the fueling cycle.
These and other features, objects, and advantages of this invention will become apparent from the following detailed description and drawing in which:
Within fuel tank 10 is fuel 18 and fuel vapor/air mix 20. As additional fuel 18 is introduced into tank 10, vapor/air mix 20 is forced from tank 10 through vent valve 22. After exiting vent valve 22, vapor/air mix 20 travels through conduit 24 which is in fluid communication with vent valve 22 and a hydrocarbon recovery system (not shown). Also fully within tank 10 is fuel level sensor 26. In a preferred embodiment, fuel level sensor 26 is a passive system such as a thermistor or other device which is able to detect the level of fuel in tank 10, however, active fuel level sensors such as a float arm or other known systems may be used without deviating from the scope of this invention. Fuel level sensor 26 is operable to send a signal to vent valve 22 when the level of liquid fuel 18 within tank 10 reaches a predetermined level.
Fuel level sensor 26 and filler nozzle sensor 16 are both electrically connected to vent valve 22 by electrical connections 28 and 30 respectively. Vent valve 22 is also supplied power from battery 32 via electrical connection 34.
Vent valve 22 is any one of a number of known valves in which the unpowered state is normally closed. Typically, vent valve will include an electromechanical solenoid which is employed to open the valve in response to an electrical signal received from filler nozzle sensor 16 via electrical connection 30, and to automatically close once the signal from filler nozzle sensor 16 is lost. Similarly, vent valve 22 will also close in response to a signal received from fuel level sensor 26 via electrical connection 28.
Control for vent valve 22 is provided by one or more logic circuits 36 located within housing 38 of vent valve 22. Logic circuits 36 allow the vent valve 22 to operate in a more controlled fashion. For example, due to sloshing of liquid fuel 18, fuel level sensor 26 may prematurely signal a full condition. In an uncontrolled system, such a signal would cause vent valve 22 to prematurely close. By adding logic circuit 36 a premature signal may be ignored, allowing proper operation of the system. In a preferred embodiment, such circuitry is physically located within housing 38 of vent valve 22 although it may be associated with alternative elements of the system without deviating from the scope of the invention.
While a preferred embodiment of the invention has been shown and described, other embodiments will now become apparent to those skilled in the art. Accordingly, this invention is not to be limited to that which is shown and described but by the following claims.
1. A vent control system operable with a tank for holding liquids comprising:
- means for detecting the initiation of a tank filling event;
- means for detecting the level of fluid within said tank;
- a power supply;
- a vent having a housing, said vent in fluid communication with said tank and also in electrical communication with said means for detecting the initiation of a tank filling event, said means for detecting the level of fluid within said tank, and said power supply; and
- logic circuits located within said housing, said logic circuits operable to open and close said vent in response to one or more electrical signals received from said means for detecting the initiation of a tank filling event, and said means for detecting the level of fluid within said tank.
2. The vent control system of claim 1 wherein said means for detecting the initiation of a tank filling event is taken from the group consisting of infra-red sensors, magnetic sensors, thermistor arrays, resistor arrays, and proximity sensors.
3. The vent control system of claim 1 wherein said means for detecting the level of fluid within said tank is a thermistor array or capacitive sensor.
4. The vent control system of claim 1 further comprising a logic circuit operable to control the opening and closing of said vent.
5. The vent control system of claim 4 wherein said means for detecting the initiation of a tank filling event is taken from the group consisting of infra-red sensors, magnetic sensors, thermistor arrays, resistor arrays, and proximity sensors, wherein said means for detecting the level of fluid within said tank is a thermistor array.
6. A method for controlling a vent in a fuel tank comprising the steps of:
- providing a fuel tank with a filler tube and a vent having logic circuits operable to open and close said vent;
- introducing a filler nozzle into said filler tube;
- detecting said introduction of said filler nozzle;
- sending a first signal to said vent;
- introducing fuel into said fuel tank;
- monitoring the level of fuel within said fuel tank; and
- sending a second signal to said vent.
7. The method of claim 6 wherein the step of sending a first signal to said vent causes said vent to open, and wherein the step of sending said second signal causes said vent to close.
8. The method of claim 6 further comprising the step of sending said second signal when a predetermined level of fuel has been introduced into said fuel tank.