WO2011037632A1

WO2011037632A1 - Fuel additive metering apparatus and method

Info

Publication number: WO2011037632A1
Application number: PCT/US2010/002610
Authority: WO
Inventors: Robert P. Queen
Original assignee: Queen Fuel Components, Llc
Priority date: 2009-09-25
Filing date: 2010-09-24
Publication date: 2011-03-31

Abstract

An apparatus for dispensing liquid chemical additives into fuel tanks. The apparatus includes a controller incorporating a programable integrated circuit, an electronic fuel tank sensor, an additive holding tank, and an additive metering pump. The fuel tank sensor communicates with the controller, and functions to measure a change in volume of fuel contained in the fuel tank after refueling. The additive holding tank stores a liquid chemical additive, and is operatively connected to an additive metering pump via a first supply line. The additive metering pump is adapted to deliver the chemical additive to the fuel tank via a second supply line. The controller communicates with the metering pump, and directs the metering pump to deliver the chemical additive to the fuel tank at a precise flow rate based on the volume change measured by the fuel tank sensor after refueling.

Description

FUEL ADDITIVE METERING APPARATUS AND METHOD

Technical Field and Background

[0001] The present disclosure relates broadly and generally to a fuel additive metering apparatus and method, and in exemplary embodiment discussed herein, enables automatic "hands free" dispensing of fuel additives into diesel fuel tanks after refueling operations. The present disclosure is applicable for use on or in combination with tractor trucks, transit buses, straight trucks, construction equipment, mining equipment, boats, generators, and the like.

[0002] Some chemical characteristics and natural impurities in diesel fuel can affect exhaust emissions from diesel engines, can damage or impede the operation of emission control devices, and can increase secondary pollutant formation in the atmosphere. The EPA, which has a mandate to assure healthy air quality, has regulated highway diesel fuel quality nearly 20 years, and has most recently established low sulfur requirements in diesel fuel. While diesel fuel specification changes at the federal level have helped reduce emissions, they have also reduced the lubricating and cleaning qualities of diesel fuel. Diesel fuel is also subject to gelling, wax crystal formation, and ice crystal formation at low temperatures. Additives are required to restore the lubricating qualities of diesel fuel and clean (keep clean) fuel system components. Additives also lower the temperature at which gelling, wax crystal formation, and ice crystal formation occurs. Additives can also improve the cetane rating of diesel fuel.

[0003] Currently, diesel equipment operators must calculate how much additive to use based on the amount of new fuel dispensed into the fuel tanks and the additive mix ratio. Additive is poured into a graduated container to measure volume and then

- 436/4PCT Page 1 - poured into the appropriate tank. This process is repeated for each fuel tank. This process is time consuming, subject to human error, and potentially hazardous due to spills or human contact with the additive. Additionally, fuel additives can cloud and gel in cold environments in a similar manner to diesel fuel. Therefore, the additive should be kept above its cloud/gel point until it can be dispensed into the fuel. This may be an increased concern in diesel equipment operated in areas where temperatures fall below 20F for a significant amount of time.

Summary of Exemplary Embodiments

[0004] Various exemplary embodiments of the present invention are described below. Use of the term "exemplary" means illustrative or by way of example only, and any reference herein to "the invention" is not intended to restrict or limit the invention to exact features or steps of any one or more of the exemplary embodiments disclosed in the present specification. References to "exemplary embodiment," "one embodiment," "an embodiment," "various embodiments," and the like, may indicate that the embodiment(s) of the invention so described may include a particular feature, structure, or characteristic, but not every embodiment necessarily includes the particular feature, structure, or characteristic. Further, repeated use of the phrase "in one embodiment," or "in an exemplary embodiment," do not necessarily refer to the same embodiment, although they may.

[0005] It is also noted that terms like "preferably", "commonly", and "typically" are not utilized herein to limit the scope of the claimed invention or to imply that certain features are critical, essential, or even important to the structure or function of the claimed invention. Rather, these terms are merely intended to highlight alternative or

- 436/4PCT Page 2 - additional features that may or may not be utilized in a particular embodiment of the present invention.

[0006] According to one exemplary embodiment, the present disclosure comprises an apparatus for dispensing liquid chemical additives into fuel tanks. The apparatus includes a controller comprising a programable integrated circuit (or logic device), an electronic fuel tank sensor, an additive holding tank, and an additive metering pump. The fuel tank sensor communicates with the controller, and is adapted for measuring a change in volume of fuel contained in the fuel tank after refueling. The additive holding tank stores a liquid chemical additive. The additive metering pump is operatively connected to the holding tank via a first supply line, and is adapted for delivering the chemical additive to the fuel tank via a second supply line. The first and second supply lines may comprise one or more conduits, tubes, hoses, pipes, or the like. The controller communicates with the metering pump, and is adapted for directing the metering pump to deliver the chemical additive to the fuel tank at a precise flow rate based on the volume change measured by the fuel tank sensor after refueling.

[0007] According to another exemplary embodiment, the electronic fuel tank sensor comprises an ultrasonic sensor adapted for mounting at an opening formed with an outside wall of the fuel tank.

[0008] According to another exemplary embodiment, means are provided for operatively connecting the fuel tank sensor to a remote electrical power source.

[0009] According to another exemplary embodiment, means are provided for mounting the additive holding tank to a vehicle.

[0010] According to another exemplary embodiment, a heating element is operatively connected to the additive holding tank.

- 436/4PCT Page 3 - too ] According to another exemplary embodiment, a thermostat is operatively connected to (or formed with) the heating element, and is adapted for regulating a temperature of the additive holding tank.

[0012] According to another exemplary embodiment, an electromechanical valve is connected to the first supply line intermediate the additive holding tank and the metering pump. The valve is adapted for opening and closing a supply of chemical additive from the holding tank to the metering pump.

[0013] According to another exemplary embodiment, the electromechanical valve comprises a solenoid valve.

[0014] According to another exemplary embodiment, a second electromechanical valve is connected to the second supply line downstream of the metering pump. This valve is adapted for opening and closing a supply of chemical additive to the fuel tank.

[0015] According to another exemplary embodiment, the second electromechanical valve comprises a solenoid valve.

[0016] In another exemplary embodiment, the present disclosure comprises a vehicle in combination with an apparatus for dispensing liquid chemical additives into at least one fuel tank of the vehicle. The apparatus includes a controller operatively connected to the vehicle's onboard electrical power source. The exemplary controller incorporates an integrated circuit, such as a programable logic device. An electronic fuel tank sensor communicates with the controller, and is adapted for measuring a change in volume of fuel contained in the vehicle fuel tank after refueling. An additive holding tank is mounted to the vehicle, and is adapted for storing a liquid chemical additive. An additive metering pump is operatively connected to the holding tank via a first supply line, and is adapted for delivering the chemical additive to the vehicle fuel

- 436/4PCT Page 4 - tank via a second supply line. The controller communicates with the metering pump, and is adapted for directing the metering pump to deliver the chemical additive to the vehicle fuel tank at a precise flow rate based on the volume change measured by the fuel tank sensor after refueling.

[0017] In yet another exemplary embodiment, the present disclosure comprises a method for dispensing a liquid chemical additive into a fuel tank. The method includes locating an ultrasonic sensor at an opening formed within an outside wall of the fuel tank. Using the ultrasonic sensor, a change in volume of fuel contained in the fuel tank is measured after refueling. The measured volume change comprises fuel- added data indicating an amount of untreated fuel added to the fuel tank. The fuel- added data is transmitted (via controller or other computing device) to an additive metering pump operatively connected to an additive holding tank. A liquid chemical additive is dispensed from the holding tank through the metering pump to the fuel tank. The chemical additive is pumped at a precise flow rate based on the fuel-added data, such that the untreated fuel is mixed on-ratio with the chemical additive.

[0018] According to another exemplary embodiment, the volume change of fuel contained in the fuel tank is measured at a predetermined time delay after refueling.

[0019] According to another exemplary embodiment, the step of locating the ultrasonic sensor comprises removing an existing cover plate attached to the fuel tank, and then mounting the ultrasonic sensor at a location of the removed cover plate.

[0020] According to another exemplary embodiment, the method includes removing an existing fuel vent attached at a vent opening formed with the fuel tank, and dispensing the liquid chemical additive into the fuel tank through the vent opening.

- 436/4PCT Page 5 - [0021] The means for implementing the exemplary methods discussed herein may comprise structural elements, components, and features which are mounted directly onboard a vehicle, such as a heavy-duty diesel-engine truck, or which may be incorporated in stand-alone or portable units designed to carry-out the various steps and acts of the exemplary methods.

Brief Description of the Drawings

[0022] The description of exemplary embodiments proceeds in conjunction with the following drawings, in which:

[0023] Figure 1 is an environmental perspective view of an automatic additive metering apparatus according to one exemplary embodiment of the present disclosure, and showing the apparatus side-mounted on a heavy-duty diesel engine truck;

[0024] Figures 2-8 are views illustrating various components and elements located inside the apparatus cabinet with the cabinet removed;

[0025] Figure 9 is a schematic view illustrating attachment of the exemplary apparatus to saddle tanks of the diesel truck and the truck's existing battery; and

[0026] Figure 10 is an additional schematic view showing the exemplary apparatus operatively attached to the truck.

Description of Exemplary Embodiments and Best Mode

[0027] The present invention is described more fully hereinafter with reference to the accompanying drawings, in which one or more exemplary embodiments of the invention are shown. Like numbers used herein refer to like elements throughout. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be operative, enabling, and complete.

- 436/4PCT Page 6 - Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention, which is to be given the full breadth of the appended claims and any and all equivalents thereof. Moreover, many embodiments, such as adaptations, variations, modifications, and equivalent arrangements, will be implicitly disclosed by the embodiments described herein and fall within the scope of the present invention.

[0028] Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. Unless otherwise expressly defined herein, such terms are intended to be given their broad ordinary and customary meaning not inconsistent with that applicable in the relevant industry and without restriction to any specific embodiment hereinafter described. As used herein, the article "a" is intended to include one or more items. Where only one item is intended, the term "one", "single", or similar language is used. When used herein to join a list of items, the term "or" denotes at least one of the items, but does not exclude a plurality of items of the list.

[0029] For exemplary methods or processes of the invention, the sequence and/or arrangement of steps described herein are illustrative and not restrictive. Accordingly, it should be understood that, although steps of various processes or methods may be shown and described as being in a sequence or temporal arrangement, the steps of any such processes or methods are not limited to being carried out in any particular sequence or arrangement, absent an indication otherwise. Indeed, the steps in such processes or methods generally may be carried out in various different sequences and arrangements while still falling within the scope of the present invention.

- 436/4PCT Page 7 - [0030] Additionally, any references to advantages, benefits, unexpected results, or operability of the present invention are not intended as an affirmation that the invention has been previously reduced to practice or that any testing has been performed. Likewise, unless stated otherwise, use of verbs in the past tense (present perfect or preterit) is not intended to indicate or imply that the invention has been previously reduced to practice or that any testing has been performed.

[0031] Referring now specifically to the drawings, a fuel additive metering apparatus according to one exemplary embodiment of the present invention is illustrated in Figure 1 , and shown generally at reference numeral 10. In the exemplary embodiment, the present apparatus 10 is side mounted on a heavy-duty diesel engine truck 11 , and functions to automatically dispense chemical fuel additives into fluidly connected, identical, top-fill, cylindrical saddle tanks 12, 14 after refueling the tanks. The precise location and mounting of the apparatus 10 on the truck 11 is illustrated by way of example only. In other exemplary embodiments, the apparatus 10 may comprise a stand-alone portable unit particularly adapted for use with portable fuel transfer tanks, small bulk tanks, and fuel pump dispensers for "off-road" refueling of heavy equipment.

[0032] In either of the above applications, the additive to fuel ratios may range from 1 :250 to 1 :8000 by volume. Fuel additives may include any chemical solution, compound, agent, or product added to diesel fuel and designed to improve performance, such as cetane number improvers, metal deactivators, corrosion inhibitors, antioxidants, rust inhibitors, dispersants, lubricity improvers, fuel stabilizers, anti-gel agents, and anti-ice agents. Additionally, the exemplary apparatus 10 may utilize or incorporate a fuel additive injector, such as the TurboDos® injector, designed

- 436/4PCT Page 8 - for larger bulk fuel tanks at terminal facilities for equipment fueled primarily at the terminal. In this embodiment, additive is mixed with the fuel as it is offloaded from larger bobtail and transport trucks. The TurboDos® injector is manufactured by Dosmatic U.S.A., Inc. of Carrollton, Texas.

[0033] In the exemplary embodiment shown, the apparatus 10 has an exterior metal or fiberglass cabinet 15 which mounts directly to the truck 11 using a convenient installation kit comprising angle irons and suitable hardware. Basic elements and internal components housed within the cabinet 15 are illustrated in Figures 2-8 (cabinet removed). As shown in Figures 2, 3, and 4, the cabinet 15 houses a large (e.g., 4- gallon) additive holding tank 21 comprising an internal heating element 22 and thermostat 23, a programmable controller 24, a metering pump 25, and cabinet heater 26. Liquid additive is inserted into the holding tank 21 by removing threaded cap 21A to access a tank opening (not shown). The metering pump 25 may have a pump head and an electric motor, an inlet line connector and an outlet line connector. As described further below, chemical additive is dispensed from the holding tank 21 through tank fitting 28, appropriate supply tubes (not shown), the metering pump 25, and upstream 3-way solenoid valve 31 and downstream 2-way solenoid valves 32, 33 to the vehicle fuel tanks 12, 14. As best shown in Figures 5, 6, 7, and 8, the programmable controller 24 communicates with switching relays 34, 35, solid state relay 36, solenoid valves 31 , 32, 33, and the metering pump 25 to direct and control metering operation of the apparatus 10. Fuse box 38 divides the electrical power feeds in the various circuits, and provides a protective breaker for each circuit in a common enclosure. The cabinet heater 26 may function to maintain the temperature of the electronic components inside the cabinet at an acceptable level.

- 436/4PCT Page 9 - [0034] During installation of the apparatus 10, information regarding fuel tank size and additive mix ratio are entered via suitable input peripheral by an operator into the programmable controller 24 via any suitable wired or wireless input peripheral (not shown). Exemplary menu selections offered by the controller 24 may include: number of fuel tanks (one or two), fuel tank cross section (cylindrical or rectangular), fuel tank diameter for cylindrical tanks, fuel tank depth and width for rectangular tanks, tank length, and additive mix ratio. The controller 24 described herein refers broadly and generally to any computing device, such as a small digital computer (or "microcontroller" or PLC) on an integrated circuit containing a processor core, memory, and programmable input/output peripherals. The exemplary controller 24 may comprise a computer adapted for real-time automation of electromechanical processes. The exemplary controller 24 may be designed for multiple inputs and output arrangements, extended temperature ranges, immunity to electrical noise, and resistance to vibration and impact. Programs to control operation of the exemplary apparatus 10 may be stored in battery-backed or non-volatile memory. The term "controller" may also refer to any other computer or computing device including a general purpose microprocessor, or a computer with a microprocessor as its central processing unit.

[0035] Referring to Figures 1 and 9, electrical power to the programmable controller 24, metering pump 25, solenoid valves 31 , 32, 33, heaters 22, 26, and other components (discussed above) within the cabinet 15 may be supplied by an onboard electrical power source, such as one or more existing vehicle batteries 40. Electric current may be supplied from the truck battery 40 though one or more operatively attached cables 41 which enter the cabinet 15 though cable hole 42. Additive supply tubes 43, 44 within the cabinet 15 extend through respective tube holes 45, 46 to the

- 436/4PCT Page 10 - vehicle fuel tanks 12, 14 where the liquid chemical additive is injected through existing tank vent openings 48 (in tank 12). As shown in Figure 9, the additive supply tubes 43, 44 are fluidly connected to identical tanks 12, 14 using standard brass T-fittings 51. With reference to fuel tank 12, the T-fitting 51 has an externally threaded male "run end" 51 A which attaches to the tank 12 at the exposed (complementary-threaded) vent opening 48. Once attached, the removed tank vent 52 is replaced at an internally- threaded female "run end" 51 B of the fitting 51. An open free end of the additive supply tube 43 is then attached using suitable connectors 53, 54 to the T end 51 C of the fitting 51. Additive supply tube 44 is attached in an identical manner to tank 14 using an identical T-fitting 51. The replaced tank vent 52 may be atmospheric venting only, pressure relief, or full function (atmospheric pressure and thermal relief).

[0036] The volume of fuel contained in the tanks 12, 14 is determined using an ultrasonic sensor 60 (in one or both tanks) operatively connected via bundled electrical cables 61 to the programmable controller 24 inside the cabinet 15. The electrical cables 61 extend from the ultrasonic sensor 60 and passes through cable hole 63 formed with the cabinet 15. In the exemplary embodiment, the ultrasonic sensor 60 is mounted directly to a single fuel tank 12 at an existing opening 65 normally covered and sealed by a sending unit cover plate (not shown). With the cover plate removed, an annular 5-hole base 60A of the ultrasonic sensor 60 can be secured using the same hardware 66 and matching 5-hole pattern 67 formed with tank 12.

[0037] To determine the amount of fuel in the tanks 12, 14, the ultrasonic sensor

60 measures the distance to the surface of the fuel. Generally, the sensor 60 uses a transducer which generates sound waves in the ultrasonic range (above 20,000 hertz) by turning electrical energy into sound. Upon receiving the echo, the transducer turns

- 436/4PCT Page 11 - the sound waves into electrical energy which can be measured and signaled to the programmable controller 24. The ultrasonic sensor 60 is calibrated to accommodate various tank geometries, and may also supply continuous real-time fuel level readings to the dashboard fuel gauge in the truck cab.

[0038] The exemplary ultrasonic sensor 60 is powered by 12V DC from the programmable controller 24, and when installed in place of an existing fuel sending unit (not shown), the replacement "ultrasonic sender" returns a non-ratiometric 0V to 5V signal (depending on fuel level in the tanks) to the input side of a converter board 68 best shown in Figures 5, 6, and 7. The converter board 68 manipulates the voltage signal into a 240 ohm to 30 ohm resistance. The output side of the converter board 68 is connected to existing dashboard fuel gage wiring. The dashboard fuel gage 71 (Figure 10) converts the resistance output from the converter board 68 into a fuel quantity reading.

Operation of the Exemplary Apparatus 10

[0039] Referring to Figures 9 and 10, after refueling the vehicle fuel tanks 12, 14, the operator turns on the truck ignition thereby supplying sufficient electric current from the onboard battery 40 through cables 41 to energize the apparatus 10. Once energized, the programmable controller 24 checks the temperature of the chemical additive stored in the additive holding tank 21 inside cabinet 15. If the initial additive temperature is below an operator-programmed value, the controller 24 will initiate an additive heating delay. The additive tank heating element 22 and thermostat 23 are energized to heat the additive to the programmed temperature. The cabinet heater 26 (with internal thermostat) may be active or inactive independent of the heating element 22. The heating delay allows sufficient time for the additive tank heating element 22 to

- 436/4PCT Page 12 - heat the additive above its cloud point. After the heating delay is completed, the controller 24 confirms that the additive temperature is above the preset value, and functions to continuously monitor additive temperature during operation of the apparatus 10. The controller 24 initiates heating anytime the additive temperature falls below the programmed temperature.

[0040] The controller 24 cooperates with ultrasonic sensor 60 to determine when refueling has taken place. Once the fuel level has stopped rising in the tanks 12, 14, the controller 24 initiates a 15-minute measurement delay. This delay allows the fuel level in both tanks 12, 14 to equalize, as the fuel is free to travel between tanks 12, 14 through a fluidly connected crossover 70. After the prescribed delay, the controller 24 takes another fuel level reading from the ultrasonic sensor 60 and assumes this to be the fuel level in both tanks 12, 14. The controller 24 then calculates the total volume of fuel added to the tanks 12, 14 during refueling, and uses this fuel-added data to direct operation of the metering pump 25.

[0041] When the controller 24 activates the metering pump 25, chemical additive stored in the holding tank 21 is drawn through the additive tank fitting 28 and open solenoid valve 31 , and through the inlet and outlet connection of metering pump 25. The metering pump 25 pumps the additive downstream at a precise (programmed) flow rate through open solenoid valves 32, 33, and outwardly from the cabinet 15 through supply tubes 43, 44 extending to respective fuel tank fittings 51. After dispensing the calculated amount of additive into the fuel tanks 12, 14, the 3-way solenoid valve 31 is energized to stop additive flow from the additive holding tank 21 while opening the solenoid port 31 A to open air. The metering pump 25 continues to operate causing air

- 436/4PCT Page 13 - to pump through downstream solenoid valves 32, 33 thereby purging the additive supply tubes 43, 44 and fuel tank fittings 51.

[0042] As indicated above, the controller 24 determines a precise amount of chemical additive to add (on-ratio) to the fuel tanks 12, 14 based on fuel-added data calculated via ultrasonic sensor 60 and transmitted by the controller 24 to the metering pump 25. Additionally, the controller 24 may convert the ultrasonic sensor voltage signal into a resistive signal. If the ultrasonic sensor 60 is installed in place of the existing fuel sender, the resistive signal is sent to the dashboard fuel gage 71 to provide fuel level information to the operator. If the ultrasonic sensor 60 is installed in place of a fuel sender cover-plate, the resistive signal is capped and not used, and the dashboard fuel gage 71 will continue to receive fuel level information from the existing fuel sender.

[0043] For the purposes of describing and defining the present invention it is noted that the use of relative terms, such as "substantially", "generally", "approximately", and the like, are utilized herein to represent an inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. These terms are also utilized herein to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue.

[0044] Exemplary embodiments of the present invention are described above.

No element, act, or instruction used in this description should be construed as important, necessary, critical, or essential to the invention unless explicitly described as such. Although only a few of the exemplary embodiments have been described in detail herein, those skilled in the art will readily appreciate that many modifications are

- 436/4PCT Page 14 - possible in these exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the appended claims.

[0045] In the claims, any means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. Unless the exact language "means for" (performing a particular function or step) is recited in the claims, a construction under §112, 6th paragraph is not intended. Additionally, it is not intended that the scope of patent protection afforded the present invention be defined by reading into any claim a limitation found herein that does not explicitly appear in the claim itself.

- 436/4PCT Page 15 -

Claims

What is Claimed:

1. An apparatus for dispensing liquid chemical additives into fuel tanks, said apparatus comprising:

a controller comprising an integrated circuit;

an electronic fuel tank sensor communicating with said controller, and adapted for measuring a change in volume of fuel contained in the fuel tank after refueling; an additive holding tank adapted for storing a liquid chemical additive;

an additive metering pump operatively connected to said holding tank via a first supply line, and adapted for delivering the chemical additive to the fuel tank via a second supply line; and

said controller communicating with said metering pump, and adapted for directing said metering pump to deliver the chemical additive to the fuel tank at a precise flow rate based on the volume change measured by said fuel tank sensor after refueling.

2. An apparatus according to claim 1 , wherein said electronic fuel tank sensor comprises an ultrasonic sensor adapted for mounting at an opening formed with an outside wall of the fuel tank.

3. An apparatus according to claim 1 , and comprising means for operatively connecting said fuel tank sensor to a remote electrical power source.

- 436/4PCT Page 16 -

4. An apparatus according to claim 1 , and comprising means for mounting said additive holding tank to a vehicle.

5. An apparatus according to claim 1 , and comprising a heating element operatively connected to said additive holding tank.

6. An apparatus according to claim 5, and comprising a thermostat operatively connected to said heating element, and adapted for regulating a temperature of said additive holding tank.

7. An apparatus according to claim 1 , and comprising an electromechanical valve connected to the first supply line intermediate said additive holding tank and said metering pump, and adapted for opening and closing a supply of chemical additive from said holding tank to said metering pump.

8. An apparatus according to claim 7, wherein said electromechanical valve comprises a solenoid valve.

- 436/4PCT Page 17 -

9. An apparatus according to claim 1 , and comprising an electromechanical valve connected to the second supply line downstream of said metering pump, and adapted for opening and closing a supply of chemical additive to the fuel tank.

10. An apparatus according to claim 1 , and comprising an electronic converter board operatively connected to said controller, and adapted for receiving a voltage signal from said fuel tank sensor and converting said voltage signal to a variable-resistance output measured by a remote operator-readable fuel gage.

11. In combination with a vehicle comprising at least one fuel tank and an onboard electrical power source, an apparatus for dispensing liquid chemical additives into said fuel tanks, said apparatus comprising:

a controller operatively connected to the onboard electrical power source, and comprising an integrated circuit;

an electronic fuel tank sensor communicating with said controller, and adapted for measuring a change in volume of fuel contained in the vehicle fuel tank after refueling;

an additive holding tank mounted to said vehicle and adapted for storing a liquid chemical additive;

an additive metering pump operatively connected to said holding tank via a first supply line, and adapted for delivering the chemical additive to the vehicle fuel tank via a second supply line; and

- 436/4PCT Page 18 - said controller communicating with said metering pump, and adapted for directing said metering pump to deliver the chemical additive to the vehicle fuel tank at a precise flow rate based on the volume change measured by said fuel tank sensor after refueling.

12. A combination according to claim 11 , wherein said electronic fuel tank sensor comprises an ultrasonic sensor mounted at an opening formed with an outside wall of the vehicle fuel tank.

13. A combination according to claim 11 , and comprising a heating element operatively connected to said additive holding tank.

14. A combination according to claim 13, and comprising a thermostat operatively connected to said heating element, and adapted for regulating a temperature of said additive holding tank.

15. A combination according to claim 11 , and comprising an electromechanical valve connected to the first supply line intermediate said additive holding tank and said metering pump, and adapted for opening and closing a supply of chemical additive from said holding tank to said metering pump.

- 436/4PCT Page 19 -

16. A combination according to claim 11 , and comprising an electromechanical valve connected to the second supply line intermediate said metering pump and the vehicle fuel tank, and adapted for opening and closing a supply of chemical additive to the fuel tank.

17. A method for dispensing a liquid chemical additive into a fuel tank, the method comprising:

locating an ultrasonic sensor at an opening formed within an outside wall of the fuel tank;

using the ultrasonic sensor, measuring a change in volume of fuel contained in the fuel tank after refueling, the measured volume change comprising fuel-added data transmitting to a controller and indicating an amount of untreated fuel added to the fuel tank;

transmitting the fuel-added data from the controller to an additive metering pump operatively connected to an additive holding tank; and

dispensing a liquid chemical additive from the holding tank through the metering pump to the fuel tank, the chemical additive being pumped at a precise flow rate based on the fuel-added data such that the untreated fuel is mixed on-ratio with the chemical additive.

- 436/4PCT Page 20 -

18. A method according to claim 17, wherein the volume change of fuel contained in the fuel tank is measured at a predetermined time delay after refueling.

19. A method according to claim 17, wherein locating the ultrasonic sensor comprises removing an existing fuel sending unit cover plate attached to the fuel tank, and then mounting the ultrasonic sensor at a location of the removed cover plate.

20. A method according to claim 17, and comprising removing an existing fuel vent attached at a vent opening formed with the fuel tank, and dispensing the liquid chemical additive into the fuel tank through the vent opening.

- 436/4PCT Page 21 -