US20080190400A1 - Vapor Fueled Engine - Google Patents

Abstract

A fuel supply assembly providing vaporized fuel to an engine wherein a quantity of liquid gasoline fuel is controllably heated for a desired vapor emission from the liquid fuel, and a conduit arrangement conducts the vapor, intermixes it with ambient air and conveys the intermixture to the engine's combustion chamber. A sensor in the engine exhaust monitors the hydrocarbon content of the exhaust and control valving controls the vapor to air intermixture in response to the monitor for maintaining a desired intermixture that produces the desired hydrocarbon content.

Description

RELATED APPLICATION
• This is a continuation-in-part of co-pending U.S. patent application Ser. No. 10/706,507 entitled “Vapor Fueled Engine” filed on Nov. 11, 2003, and claims priority to said '507 application.
FIELD OF THE INVENTION
• This invention relates to the use of vaporized fuel to power an engine and, more particularly, to improvements that enhance fuel efficiency.
BACKGROUND OF INVENTION
• It is known that under some conditions the use of vaporized fuel versus liquid fuel for gasoline powered vehicles can reduce the emission of hydrocarbons conveyed into the atmosphere, while also increasing fuel efficiency. The problem that has lingered is how to obtain and retain those benefits over the changing conditions in which such vehicles are typically driven.
SUMMARY OF THE INVENTION
• As known and as described in the commonly owned U.S. patent application Ser. No. 10/002,351, now U.S. Pat. No. 6,681,749, (incorporated herein by reference), fuel efficiency can be improved by heating a quantity of gasoline to cause vaporization, directing the vapor into a stream of ambient air, establishing a desired air-to-fuel mixture and directing the mixture into the intake manifold of an engine.
• Whereas the system as disclosed in the above application has resulted in significant improvement, it has not achieved the consistency of operation desired.
• It is known that there is an optimum fuel-to-air mixture that needs to be maintained. A fuel-to-air mixture of 1 to 20 is likely too rich resulting in an unacceptable percentage of hydrocarbons in the fuel that are not properly combusted and fuel efficiency is reduced. A 1 to 40 mixture is too lean with today's catalytic converters (CATs) and produces an emission of nitrogen oxide that is prohibited by the EPA emission standards. A fuel-to-air mixture of about 1 to 30 is about optimal for current gasoline engines used in vehicles and an objective of the invention is to control the fuel-to-air mixture to maintain the ratio in the range substantially at, e.g., 1 to 30.
• Consistent with the above objective, the mixture is monitored and adjusted throughout operation of the engine. This is accomplished automatically by the use of valves that control the flow of vapor fuel and/or ambient air that is mixed prior to entry of the vapor fuel into the engine's intake manifold. The valves are coupled to a control that is in turn coupled to a vehicle's 02 sensor which senses 02 emissions in a vehicle's exhaust (a standard feature on most modern vehicles.) It has been learned that the 02 emissions are directly related to hydrocarbon emissions which as explained is a reflection of the fuel-to-air mixture.
• In the preferred embodiment, an electrical output from the 02 sensor is transmitted to the mentioned control. It is known that the desired reading for the voltage output of the sensor as measured by the control is, e.g., 3 volts. At startup, the reading will typically be at, e.g., 4 volts, indicating a too rich mixture but desirable for startup and warming of the engine. After a time delay to accommodate warm up, any reading above or below, e.g., 3, will activate the control for opening and closing the valve or valves which control ambient air flow and vaporized fuel flow (more accurately an enriched mixture of air and fuel). For example, a 3.2 reading will produce an opening of the ambient air valve and/or a closing of the vaporized fuel flow. A 2.8 reading will produce the reverse.
• Whereas it would be presumed and has been assumed that an established fixed setting of fuel-to-air mixture would produce a stabilized mixture throughout the operation of the engine, such has been determined to be not the case. There are many variables that need to be controlled or accommodated. The liquid fuel temperature is known to have the greatest impact on hydrocarbon emissions and fuel efficiency, and that temperature will vary by small but very significant degrees of temperature due to environmental changes, i.e., temperature, elevation, humidity, and the like. Thus, in the preferred embodiment, a quantity of fuel to be vaporized is precisely temperature controlled to substantially eliminate the effect of such environmental variables.
• Regardless, there still remain significant changes that are not controlled simply by maintaining the liquid fuel temperature. These remaining variables are accordingly accommodated by monitoring the 02 sensors. To the extent that the fuel mixture strays from the desired reading from the 02 monitor, the mixture is corrected, i.e., by changing the setting of a valve or valves.
• Whereas the above improvements are considered the primary features for the preferred embodiment, the following is also considered to provide additional benefit.
• Again in the preferred embodiment, a quantity of liquid fuel, e.g., one gallon of fuel, is inserted into a vaporization tank. The fuel occupies, e.g., the lower half of the tank, and a heating element and temperature sensor is provided in the fuel-containing portion of the tank. The temperature is set and maintained at, e.g., 74 degrees, and that temperature causes vaporization of the fuel, the vapor rising from the liquid surface into the upper half of the tank. Within the tank, in the upper half, there is an ambient air inlet and a vaporized fuel outlet. A sequence of baffles directs air from the inlet and across the surface of the liquid fuel to the outlet which is connected to an outer first conduit. The ambient air temperature is stabilized by its movement over the liquid and in the process mixes with the rising fuel vapor. As expelled through the outlet and into the first conduit, such becomes the vaporized fuel heretofore alluded to and which is perhaps more correctly identified as an enriched fuel air mixture. A secondary source of ambient air is conducted through a second conduit and merges with the vaporized fuel of the first conduit. Prior to said joining of the air and vaporized fuel, at each or a selected one of the first and second conduits, control valves are provided which control the flow volume from the respective conduits to vary the amount of ambient air and vaporized fuel that is combined into a third conduit or continuing conduit (also referred to as a mixing chamber) which in turn conveys the mixture to the engine's intake manifold.
• A further problem for which a solution had to be derived was the discovery that the process as described, when vaporizing the common gasolines that are commercially available, generates a liquid residual that does not readily vaporize, e.g., at the temperature setting considered otherwise optimal. Over a period of time, this liquid residual becomes a greater and greater portion of the liquid content of the vaporization tank. Thus, a provision is made for a periodic purging of the liquid residual from the tank.
• Whereas it was determined that the residual liquid burned acceptably well in conventional engines, and particularly to the extent that the systems of the preferred embodiment are adaptable and applied as retrofits to such conventional engines, a first solution is the alternate running of the engine, i.e., on vaporized fuel as described above, and then, as desired, converting back to conventional liquid fuel operation wherein the residual liquid is used to fuel the engine. A recycling procedure may be established to (a) fill the tank with e.g., a gallon of liquid gasoline; (b) vaporizing 80% of the fuel and then switching to conventional engine operation to burn off the liquid residual; and (c) refill the tank and switch back to vaporized fuel. Other solutions are certainly contemplated. The residual can be simply extracted from the tank on a periodic basis, stored until refueling is required, and then disposed of or preferably transferred for use in a conventional engine use.
• A further enhancement to fuel economy was discovered by incremental increases in the temperature settings for heating the fuel in the vaporization tank. For example, it may be found optimal to heat the fuel to a temperature of e.g. 80 degrees at the outset, but the chemical makeup of that fuel changes as the more active component of the fuel vaporizes. The same temperature produces less vapor and the engine will detectably lose power. At a detected power loss it may be desirable to raise the temperature e.g. to 82 degrees which will increase vaporization and reinstate the power. Whereas theoretically the heat can be repeatedly increased to the point where virtually all of the fuel is vaporized, it is considered a more desirable practice to stop the incremental heating at a point where the residual component can still be effectively used as a liquid fuel. For example, the temperature can be increased in 1 or 2-degree increments up to 100 degrees (or where substantially 80% of the fuel is vaporized). At that point the process is interrupted and the vaporizing tank purged and refilled with fresh fuel.
• The invention will be more fully appreciated and understood by reference to the following detailed description and drawings referred to therein.
DESCRIPTION OF THE FIGURES
• FIG. 1 is a schematic overview of a preferred embodiment of the invention;
• FIG. 2 is an operational diagram of the system utilized for the embodiment ofFIG. 1;
• FIG. 3 is an exploded view of the vaporization tank ofFIG. 1; and
• FIG. 4 is a further exploded view illustrating in particular the control valves of the system ofFIGS. 1 and 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
• Reference is made toFIG. 1, which provides a schematic overview of the components of a system in accordance with the present invention. A gasoline-powered engine as labeled, includes anintake port10 connected to the engine's throttle body. The engine, when operating, draws air and fuel throughport10. The engine includes anexhaust pipe12 that is equipped with an 02sensor14. The engine,intake port10 and 02detector14 may be standard equipment provided for a conventional gasoline-driven vehicle, and the remainder of the components of the illustrated embodiment are incorporated into the system to achieve the objectives of the present invention.
• Item16 represents an air box through which ambient air is drawn when operating the engine.Air conducting conduits18 and20 fromair box16 provide the desired airflow to the remainder of the system as will be described.
• Conduit20 includes avalve22 that controls the volume of air directed throughconduit20 and which is conveyed to avapor producing tank26 via the tank's top orcover24.
• Conduit18 includes avalve28 which controls the volume of ambient air that is directed into a mixingchamber30.
• Returning to the vapor-producingtank26, the tank is provided with flow control apparatus, e.g., baffles, which will be later explained, but for this overview description it will be understood that air from conduit20 (as controlled by valve22) enters thetank26 through the top24,liquid fuel28 is drawn from agas tank32 viaconduit34, hot water heating coils immersed in the liquid fuel via inlets andoutlets36,38 heat the gas/fuel28 and generatevapors40. The vapors are picked up by the airflow fromair conduit20 and directed out throughconduit42 to the mixingchamber30 but controlled byvalve44. The air vapor mixture ofconduit42 is intermixed in mixingchamber30 with ambient air fromconduit18, and the mixture is directed through theintake port10 and from there into the combustion tank of the engine.
• Reference is now also directed toFIG. 2 which illustrates an automatic control process for the air, vapor, and fuel flow rates referred to inFIG. 1. Eachvalve22,28 and44 are opened and closed as desired (between any of the unlimited positions between fully opened and fully closed) by motors, e.g.,stepper motors22′28′ and44′.
• It has been determined that fuel efficiency can be measured by the hydrocarbons that are emitted from the vehicle exhaust. Unfortunately, the elimination of hydrocarbons from gasoline-produced engines currently available cannot be total as such produces an undesired and unpermitted emission of nitrogen oxides. Thus, one first determines the level of nitrogen oxide that is permitted and then the lowest level of hydrocarbons that will stay within the limits permitted for the restriction on nitrogen oxide.
• It has further been determined that 02 detectors for detecting a level of 02 in the vehicle's exhaust and which have been incorporated into the exhaust system of later model vehicles, are directly related to the level of hydrocarbons in that same exhaust. Thus, one can determine what 02 reading of thedetector14 produces the optimum fuel efficiency. For example, a desired hydrocarbon level may be determined to exist when the 02 monitor produces a reading of 3 volts.
• Returning toFIG. 1, it has been determined that fuel efficiency is achieved by controlling the ratio of fuel-to-air mixture achieved at the mixingchamber30 from which the mixture enters the engine intake throttle body. It is known that the vapor-air-mixture directed into the mixingchamber30 fromconduit42 is too rich, e.g., 1 part fuel to 10 parts air, and of course the air only fromconduit18 has zero parts fuel. The desired mixture may be that which achieves a 30 to 1 ratio, e.g., of 2 cubic feet of air, throughvalve28 for each cubic foot of air/vapor throughvalve44.
• Whereas thevalves28 and44 can be set to achieve the desired mixture at a given point in time, it has been learned that many factors affect the ratio achieved in the vapor/fuel mixture flowing throughconduit42.
• Assuming a specific hydrocarbon emission is desired, a reading of the 02 detector will verify that this desired mixture has been achieved, as that reading also indicates the hydrocarbons in the exhaust. As explained, a fixed setting will not likely achieve the optimum ratio over any given period of time. Any temperature change, any elevational change and even differences in fuel make up will skew the vapor/fuel mixture flowing from thetank26 to the mixingchamber30.
• Accordingly, thevalves22,28 and44 are operated bystepper motors22′,28′ and44′ (illustrated in the flow chart ofFIG. 2 and in exploded perspective view inFIG. 4) which stepper motors are automatically operated by computer C. Computer C monitors the 02 and thus the hydrocarbon emissions inexhaust12 and should those readings indicate too high or too low hydrocarbons, the stepper motors are activated by the computer to change the relative fluid volumes fromconduit18 andconduit42. Should the reading show a too high hydrocarbon level, the vapor/air flow ofconduit44 needs to be lessened, e.g., thevalve44 closed, or, e.g., thevalve28 opened, or, e.g., both closing ofvalve44 and opening ofvalve28.
• The adjustment may take place in stages, i.e., a 1° closing ofvalve44, a re-reading of the 02 detector followed by repeated partial closing ofvalve44 or alternatively the partial opening ofvalve18 or a combination of both.Valve22 can also be a factor as restricting air flow intoconduit20 will slow the flow of air to thetank26, thus toconduit42, while also diverting more airflow throughvalve28.
• The structure as described enables the designer to design a system that will theoretically provide the desired result in fuel-to-air mixture (e.g., 1 to 30) as deemed desirable, but then in recognition of the impact of small environmental changes that produce substantial deviations in efficiency, provide automatic adjustments that are responsive to real time readouts from an exhaust monitor, e.g., an 02 detector.
• Reference is now made toFIG. 3, which illustrates the components of the vaporizingtank26. Thetank26 consists of ametal box48 having dimensions of about 4″×8″×12″. Fitted to the bottom of the tank is ahot water coil50 that includes aninlet52 andoutlet54 which, when assembled to thebox48, extends from the box viainlet52′ andoutlet54′.
• Seated onto the box bottom and over thecoil50 is abaffle grid56. The plates of thebaffle grid56 includeslots58 which enable the seating of the grid over thecoil50.Baffle grid56 includesfastener tabs60 and assembled to thefastener tabs60 is alower baffle plate62 having spacedcircular opening64. Thebaffle plate62 is seated below the upper edge of box48 (defined by flange84) and affixed to theflange84 is anupper baffle plate66. Extendingflanges68 ofbaffle plate66 protrude laterally from the box and provide the means to secure thebox48 to the body of the vehicle.Upper flange68 hasrectangular openings70.
• Secured to theupper baffle plate66 and in alignment with an air inlet to be described is a secondaryupper baffle plate72, reduced in size and secured to theupper plate66 so as to cover a substantial portion of theopening70′. Provided in this secondary plate is a plurality of small holes, e.g., fiveholes74 having a size of about a quarter inch in diameter.Baffle plate72 provides an impediment to airflow fromair inlet78 and diverts the air flow laterally and downwardly within thetank26.
• Completing the assembly is the top or cover24 which has a complex shape which can be described as a distorted pyramid shape. The apex of the pyramid shape is positioned at one end whereat anair inlet78 is provided Avapor air outlet80 is provided at the same end but along the side wall of the pyramid shape. Theflange82 forming the peripheral edge of the top24 includes bolt holes which line up with bolt holes inflange portion76 ofbaffle plate66 and with bolt holes in aflange84 forming the peripheral edge ofbox48. Bolts (not shown) are inserted through the aligned bolt holes to fasten the components together. Afloat86 contained in thebox48 determines the level of liquid gasoline contained in the box. The liquid gasoline enters the box throughconduit34 and arecycling conduit90 is provided to drain and/or circulate the gasoline in the vaporizingtank26 as may be desired.
• In operation liquid gasoline is filled to a level of about ¾ inch in the bottom of thebox48 which is above the position of the heater coils50 and below the top of thebaffle grid56. Thebaffle grid56 andbaffle plate62 primarily prevent sloshing of the gasoline during driving of the vehicle. As the liquid gasoline vaporizes (induced by the heating coil50) air frominlet78 is dispersed across the liquid surface viabaffle plates72 and68 which collects vapors40 (seeFIG. 1) and is then directed throughoutlet80 and to the mixingchamber30 viaconduit42 as previously discussed.
• As gasoline is vaporized and drawn from the surface of the liquid gasoline, the gasoline level diminishes which is detected by thefloat86. As determined desirable by the system, the gasoline is replenished throughinlet34. After some period of time, the gasoline starts to become contaminated (does not vaporize) and it is desirable to purge the tank. This can be done by converting the engine to gasoline use and drawing the residual gas of thetank26 through the conventional gas injection system. It can also be simply drained into a holding tank and utilized for other power equipment, e.g., a powered law mower.
• As explained in the Summary of the Invention, a further improvement is the controlled modification to the temperature of the fuel in the vaporization tank. The temperature at the outset is established to provide a desired vaporization of a quantity of fresh fuel, e.g. 74 degrees (but note this initial desired temperature will likely change with different fuel types and for example 80° may be just as valid a start temperature). A temperature sensor previously referred to is utilized to control the heat generated by a heating source, e.g. the indicated water heating coils immersed in the liquid fuel.
• The power generated by the engine at the initial fuel temperature is monitored and when a determined power loss is detected, the temperature of the fuel in the vaporization tank is increased, e.g. by 1 or 2 degree increments. The loss of power is simply a result of the above described vaporization process. The liquid gasoline produces more vapors initially than it does as time goes on. The engine requires a quantity of vapor to run correctly and that quantity of vapor exists when the gasoline is fresh but not after some time vaporizing. This loss of power is detected by the 02 sensor that reports the air to fuel ratio. Many things such as high or low levels of hydrocarbons, carbon dioxide and oxygen can be derived from the 02 sensor. When there is a loss of power, the hydrocarbons and carbon dioxide levels go extremely low and the oxygen level goes extremely high as well as higher air to fuel ratio. Any or all of these can be utilized as a signal for loss of power.
• The initial cure to the power loss is to adjust either theambient air valve28 orvapor value44 or both. As the vaporization process continues, the ambient air valve will close and the vapor valve will open in response to the less and less potent liquid gasoline that is producing the required vapor. Eventually the vapor valve will be fully opened and the free air valve will be fully closed. At this point the temperature of the fuel is increased. Heating the gasoline in 1 or 2 degree increments is enough to increase the production to adequately provide the needed fuel vapors to the engine. As the heat is increased, the vapor valve moves away from its fully opened position until the new temperature is no longer adequate at which time the vapor valve opens and will eventually will be fully opened until more heat is added to the liquid gasoline. The process will repeat itself until a predetermined temperature is reached at which time the remaining liquid is drained, e.g., using the stock fuel injection system.
• The formula for signaling the change from vapor to liquid fuel is as follows: highest allowed heat of liquid gasoline plus vapor valve fully opened plus input that the engine is no longer being provided the needed vapor to perform properly equals switch from vapor system to stock fuel injection system and burn-off residual liquid.
• The system is designed so that the residue in the tank does not become so contaminated that it cannot be effectively used as a liquid fuel supply. For example, it may be determined that a power loss detected with the fuel in the tank heated to 100 degrees will trigger the switch-over, i.e., purging of the tank. Other triggering mechanism may be utilized such as monitoring the fuel volume and initiating switch-over, e.g. when 80% of the fuel is depleted.
• Whereas the above is considered a preferred embodiment, the reader will readily understand that numerous modifications and variations may be made without departing from the intended scope of the invention. Accordingly, the invention is not limited to the structures as described above but fully encompasses the definitions of the appended claims.

Claims (21)

1-4. (canceled)

5. A fuel supply assembly comprising:

a vaporization tank to vaporize an amount of fuel;

an air conduit to induct air and intermix the vaporized amount of fuel with the air prior to entry into a combustion chamber;

a controller adapted to control the vaporization of the amount of fuel by incrementally increasing the temperature of the amount of fuel prior to combustion.

6. The fuel supply assembly ofclaim 5 wherein the controller further controls a plurality of valves coupled to the air conduit, the plurality of valves adapted to control the intermixing of the vaporized amount of fuel with the air.

7. The fuel supply assembly ofclaim 6, wherein the controller controls the plurality of valves to maintain a desired air-to-fuel mixture.

8. The fuel supply assembly ofclaim 7, wherein the controller controls the plurality of valves to maintain a desired air-to-fuel mixture of approximately 14.7 to 1.

9. The fuel supply assembly ofclaim 5, wherein the controller incrementally increases the temperature of the amount of fuel in response to a detection of a condition change.

10. The fuel supply assembly ofclaim 9, wherein the condition change is a loss of power.

11. The fuel supply assembly ofclaim 5, wherein the controller incrementally increases the temperature of the amount of fuel in response to an O₂sensor detecting low hydrocarbon levels.

12. The fuel supply assembly ofclaim 5, wherein the controller incrementally increases the temperature of the amount of fuel by increments of about one degree.

13. The fuel supply assembly ofclaim 5, wherein the controller incrementally increases the temperature by increments of about two degrees or more.

14. A method comprising:

inducting an amount of fuel into a vaporization tank;

incrementally increasing the temperature of the amount of fuel in the vaporization tank to vaporize different portions of the amount of fuel;

intermixing an amount of air with the different vaporized portions of the amount of fuel; and

controlling the intermixing of the different vaporized portions of the amount of fuel with the amount of air to maintain a desired air-to-fuel mixture.

15. The method ofclaim 14 wherein incrementally increasing the temperature of the amount of fuel comprises increasing the temperature of the amount of fuel by increments of approximately two degrees or more.

16. The method ofclaim 14 wherein controlling the inducting of the amount of air into the vaporization tank comprises controlling a plurality of valves coupled to an air conduit adapted to induct the amount of air.

17. The method ofclaim 14, wherein the incrementally increasing the temperature of the amount of fuel comprises incrementally increasing the temperature of the amount of fuel in response to a detection of low power.

18. The method ofclaim 14, further comprising monitoring hydrocarbons in combustion exhaust, and incrementally increasing the temperature of the amount of fuel in the vaporization tank in response to detecting a determined hydrocarbon level.

19. The method ofclaim 14, further comprising purging the vaporization tank.

20. The method ofclaim 19, further comprising purging the vaporization tank in response to the temperature of the amount of fuel reaching a determined temperature.

21. A method comprising:

inducting an amount of fuel into a vaporization tank;

intermixing an amount of air with vaporized portions of the amount of fuel to create a fuel charge of a desired air-to-fuel ratio; and

increasing the temperature of the fuel charge prior to the fuel charge entering a combustion chamber.

22. The method ofclaim 21, wherein increasing the temperature of the fuel charge comprises increasing the temperature of the amount of fuel inducted into the vaporization tank.

23. The method ofclaim 21, wherein increasing the temperature of the fuel charge comprises increasing the temperature of the amount of air by increasing the temperature of the amount of fuel inducted into the vaporization tank.

24. The method ofclaim 21, wherein increasing the temperature of the fuel charge comprises increasing the temperature of the vaporized portions of the amount of fuel by increasing the temperature of the amount of fuel inducted into the vaporization tank.

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