US3289711A - Device for controlling the hydrocarbon evaporation losses from automotive vehicles - Google Patents

Description

Dec. 6, 1966 F. v. HALL 3,289,7M

DEVICE FOR OONTROLLING THE HYDROOARBON EVAPORATION LOSSES FROM AUTOMOTIVE VEHICLES Original Filed Aug. 18, 1960 INVENTOR.

FRED 1/ y 'AL/2 United States Patent O 3,289,711 DEVICE FOR CONTRLLING THE HYDROCAR- BN EVAPORATlON LOSSES BRGM AUTOMO- TIVE VEHICLES i Fred V. Hall, San Francisco, Calif., assigner to Brooks Walker, San Francisco, Calif. Continuation of application Ser. No. 407,946, `liuly 27, 1964, which is a division of application Ser. No. 50,509, Aug. 18, 1960, now Patent No. 3,191,587. This application Dec. 13, 1965, Ser. No. 517,501

2 Claims. (Cl. 141-286) This application is a continuation of application Serial No. 407,946, tiled July 27, 1964, which was a division of application Serial No. 50,509, tiled August 18, 1960, now United States Letters Patent No. 3,191,587.

This invention relates to a device to control the hydrocarbon evaporation losses from automotive vehicles. More particularly, it controls the hydrocarbon evaporative loss from the carburetor and gas tank of automobiles and trucks.

It has been established that automobiles constitute a significant source of atmospheric pollution, leading to the :smog problemV in many cities. In Los Angeles automobiles appear to be the major source. While the bulk of the polluting emissions come from the automobile exhaust, in the form of'unburned hydrocarbons and nitrogen oxides, unburned hydrocarbons also pass into the atmosphere from the carburetor and fuel tanks by evaporation. While the amount may not seem to be great enough in one automobile to cause the owner to think he is suffering from this waste, the compounding of the pollution effect by millions of automobiles in such areas as Los Angeles has led tomajor problems. The present invention is intended to solve this problem of evaporation loss, just as my Patent 2,809,623 solves the problem of keeping the unburned hydrocarbons escaping via the automobile exhaust within allowable units.

There are several kinds of hydrocarbon loss by evaporation from automobiles:

(l) Carburetor running losa- This term refers to the loss of hydrocarbon vapors from the carburetor though external vents while the engine is running. Most carburetors are equipped with external vents for the pur- 'pose of releasing the vapors boiling olf in the carburetor, because it such vapors are not vented, the air-fuel mixture tends to become richer at elevated temperatures. External ventilation results, however, in a loss of fuel by evaporation while the engine is running (hence the term running loss), the amount of loss generally being highest during engine idling at times when the engine is hot after a prolonged run at high speed or high ambient temperature or both. However, significant amounts may also be lost during cruising and other operating phases. Some ,carburetors are internally vented; these, while not having this problem, have heretofore accentuated the exhaust problem by causing rough engine operation, due to overrich mixtures at high under-hood temperatures, and they have upset the air-fuel ratio that the carburetor is intended to provide.

(2) Carburetor' "Ilot Soak loss-When an engine stops running after having become hot, the carburetor tends to be heated by the soak back of engine heat. The temperatures in the carburetor bowl rise substantially after a hot shutdown, and this increase in temperature boils fuel out of the carburetor bowl, (hence the term hot soak loss), the boiled-out `fuel passing to the atmosphere via the external vent or the air cleaner in the form of unburned hydrocarbons. This hot soak loss occurs during about the irst half-hour after shutdown of a hot engine; after this time, the loss is relatively insignificant, because by that time the more volatile portions of the CII 3,289,711 Patented Dec. 6, 1966 gasoline in the carburetor bowl have already evaporated and the engine has become cool.

(3) Tank breathing loss.-Temperature fluctuations cause the gasoline tank to breathe," due to expansion and contraction of the gases in the vapor space above the liquid level. Hydrocarbon vapors are forced out of the tank during expansion, hence the term tank breathing loss. rl`he vapor pressure of the summer grade of gasoline is roughly eight pounds per square inch at F., and therefore the amount of evaporation is significant, especially on a hot day. The evaporated gasoline passes through the vent line of the gasoline tank out into the atmosphere.

(4) Tank lling loss.When a gasoline tank is being filled at the filling station, a volume of hydrocarbon vapor and air approximately equivalent to the amount of liquid gasoline added into the tank is displaced and passes into the atmosphere, thereby aggravating the problem.

(5) Overflow lose-When a gas tank is overlled or when an automobile is parked in an inclined attitude, as on the hills in many cities, an overflow of liquid gasoline may pass through the vent line, spill on the ground, and subsequently evaporate into the atmosphere.

The present invention solves all live of the above problems by a novel combination of elements. For example, carburetor running loss is controlled by inducting tjhe vapors into the intake air of the engine while supplying additional combustion air with a thermal leaning device. This thermal leaning device also operates to prevent rough engine operations that tends to result when the carburetor is internally vented. In the invention, the normally external vents of the carburetor are plugged if there are ample internal vents, or the external vents are diverted so that they vent internally, thus completely eliminating carburetor running loss.

The invention solves the problem of hot soak loss by trapping the vapors in an activated adsorbent or in an absorbent, which is later automatically regenerated by desorbing. A mechanism is provided for actuating the adsorber or absorber system during only the first half hour and then turning the mechanism off automatically. instead of being timed, however, the mechanism is preferably dea-ctuated by temperature so that when the engine is cool, this device is turned off.

The invention prevents the evaporative losses due to tank breathing and filling by guiding the vent line from the tank through the adsorbing or absorbing mechanism. Furthermore, the invention provides a novel connection at the tank inlet spout and a filling nozzle adapter, which may be used at the service station to obtain a vaportight connection between the service station dispensing pump and the fuel tank.

Finally, the invention prevents the losses that tend to occur when the tank overliows, not only by routing the vent line through the absorbing or adsorbing agent but more particularly by providing an elevated gooseneck with an ample drop-out pot or liquid trap that prevents overflow and spillage loss.

Other objects and advantages of the invention will appear and the above ones will 'be explained more clearly and understood better from the following description of a preferred embodiment of the invention presented in accordance with the statutes.

In the drawings:

FIG. l is a schematic diagram of a system embodying the principles of the present invention for preventing evaporation losses from an automotive engine and fuel system.

FIG. 2 is an enlarged view in elevation of a regenerative absorbing or adsorbing filter that may be used in this invention.

FIG. 3 is an enlarged view in elevation of a springloaded check valve of a type that may be used Ain this invention.

FIG. 1 shows a gasoline engine 10 and pertinent portions of a system concerned with this invention. Its fuel system comprises a gas tank 11 provided with a filling spout 12, a vent line 13 and a fuel line 14. The fuel line 14 leads via a fuel pump 14a to a carburetor 15, which has an air cleaner 16 for intake air and is vented internally by a tube 16a. Similarly, a circuit diagram of a portion of the engines ignition system is shown, with a battery 17, an on-off switch 18, a coil 19, a distributor 20, and a spark plug 21.

The present invention provides a duct 22 that leads from the air cleaner 16 to an electrically driven air pump 23 having a motor 24. The motor 24 and air pump 23 are operated only when the ignition switch 18 is in the off position and only when a bimetallic thermal delay switch 25 is closed. This thermal delay switch 25 is mounted where it Will be sensitive to engine heat; it may be on the exhaust manifold (not shown) or some other similarly convenient location. When the manifold (and engine) is hot, the switch 25 is closed, but it opens when the manifold cools, the temperature characteristics of the switch 25 being adjusted to give the proper opening time, usually corresponding to a normal delay of about one-half hour. Thus, it will be evident that the air pump 23 operates only when the engine 10 is both off and hot.

A discharge line 26 from the air pump 23 leads to a filter 27 (FIG. 3) containing suitable absorbent or adsorbent material 28 such as charcoal, oil on crushed fire brick, or any other suitable gasoline-adsorbing or absorbing material. The fuel tank vent line 13 also leads to` the same filter 27. One end of the filter 27 is open to the atmosphere through a screen 29. A conduit 30 from the ilter 27 leads to a thermal leaning device 31, which is connected by an idle air duct 32 to the carburetor 15. The thermal leaning device 31 may be that shown in my Patent 2,809,623 or other means for leaning the carburetor mixture when the temperature gets hotter. It is shown in somewhat more detail in FIG. 2. It will be noted that the line 30 enters opposite the line 32 and that there is a bimetallic thermally operated pad valve 33 that controls air flow from outside air into a passage 34. The passage 34 is restricted by a needle valve 35, so that the needle valve 35 controls the air flow of supplementary fresh air which is added as the temperature rises. A temperature range screw 36 may be provided to vary the activating temperature of the thermal element 33. The basic idle air requirement of the engine is controlled by an adjustment valve 37.

In the vent line 13 between the tank 11 and the lter 27 there is a drop-out pot 40 elevated above the tank 11 in a gooseneck 41 to retain liquid gasoline and return it to the tank 11. There is also a spring-type check valve 42 (FIG. 3).

An opening 43 on the spout 12 of the gasoline tank 11 is connected to and closed by an adapter 44 on the nozzle spout 45 when filling the tank 11 from a conventional automatic shutofic service station nozzle 46, to provide a vaportight connection at that point.

OPERATION When the fuel tank 11 is filled with gasoline, a vaportight connection is provided by the adapter 44, which may have a neoprene seal at both ends. All the gasoline vapors then in the tank 11 are displaced through the vent line 13 rather than passing back up out of the spout 12. Thus, they pass to the filter 27 where the vapors are absorbed or adsorbed to a very large degree.

All gasoline tanks which are normally vented to the atmosphere breathe, and when they breathe they exhale some gasoline vapor. Moreover, since gasoline has a rather high vapor pressure, loss constantly occurs during hot days due to evaporation, and this loss is increased by the breathing action of the tank. In this invention, as has been shown, the breathing action takes place only through the activated carbon 28 or other adsorbent or absorbent in the lter 27, which sorbs the hydrocarbon vapors with a high degree of efficiency.

Tank overflow loss has heretofore been combatted by simply placing the vent line 13 in the tank 11 at the highest point and by providing an elevated gooseneck 41. However, these vents are not elevated enough to prevent overflow loss under all conditions, and frequently vehicles parked in an inclined attitude or speeding around corners have lost gasoline out of the overflow vent. Here, the drop-out pot 40 just below the highest point in the gooseneck 41 protects against this. In the event that liquid gasoline is forced through the vent 13, it collects in the drop-out pot 40 and later drains back into the gasoline tank 11.

During operation of the vehicle, carburetor running loss is prevented by inducting the vapors into the intake air of the engine via the internal vent 16a supplying additional combustion air through the thermal leaning device 31 to prevent abnormal enrichment of the mixture, according to my Patent 2,809,623. This invention also calls for either plugging the normal external vent to the carburetor 15, if there are ample internal vents, or diverting them so that they do vent internally. The carburetor 15, being internally vented by the vent 16a, has no carburetor running loss, and the thermal leaning device 31 prevents overrich air-fuel ratio from being furnished to the invention and prevents rough engine operation, which is itself a cause of excessive exhaust pollutants, as explained in Patent 2,809,623.

After the automobile has been run awhile and then is parked, the engine heat soaks back to the carburetor 15 and boils off vapor which have heretofore been emitted either through the air horn or `through external vents of the carburetor. In the present invention the vapors are trapped in the filter 27 and absorbed or adsorbed by the agent 2?) therein. Thus, when the engine 1i) is shut down, the ignition switch 18 is turned to the engines off position, which is the on position for the motor 24. If the engine manifold is hot, the switch 25 will be closed. The switch 25, a simple bimetallic thermal element adjusted to open when the engine temperature drops below a desired level, will, when the engine is hot, conduct current from the battery 17 and this results in energizing the motor 24 for the air pump 23, which then pumps the air laden with gasoline vapors from the air cleaner 16 and the carburetor vapors into the filter 27 through the conduits 22 and 26. In about one-half hour the exhaust manifold will have cooled to the point (e.g., F.) where the thermal switch 25 opens and shuts off the air pump 23, it no longer being required. In fact, the thermal switch 25 will open even when the under-hood temperatures are quite hot, as they are when the car is parked in the sun on a hot day, for the temperature of a hot exhaust manifold of an engine that has been running is much hotter than such under-hood temperatures due to the sun.

The adsorber or absorber 28 collects and retains the hydrocarbons from the hot soak loss, the tank breathing loss, and the tank filling loss. In order for the absorber or adsorber to continue to function efiiciently, it might be thought tha-t fresh activated carbon would be required periodically, but this would be undesirable both from an expense and convenience standpoint; so the present invention provides a system for automatically regenerating the carbon or other agent 28 after each engine start-up and during the subsequent normal operation of the vehicle. This is accomplished by a reverse-how process in which the idle air requirement is drawn into conduit 30 through the carbon absorber in the reverse direction. Thus, by connecting the tube 30 to the absorber or adsorber filter 27, a portion of the engine air requirement flows in reverse through the carbon adsorber during all part-throttle operation, passing through the thermal leaning device 31, and then through the conduit 32 to the carburetor 15. During such operating cycles as lowpower cruise or idle, whenever a relatively high partial vacuum exists in the intake manifold, this reverse air How through the conduit 30 will result. The air ow requirement of the engine is very large in comparison with the small quantities of vapors adsorbed on the carbon and so this large quantity of air passing through the adsorber desorbs the hydrocarbon vapors from the carbon and these are subsequently burned in the engine. The engine fuel requirement being very large in comparison with the small amount and low rate at which these vapors are introduced into the engine, no significant change in the air fuel ratio occurs in the engine, yet these materials are used.

Thus, the present invention, especially when used in combination with the thermal leaning device 314 of my Patent 2,809,623, cuts down the evaporation losses from automobiles to a negligible amount. Thereby it can considerably alleviate the smog problem if the device is installed on a substantial number of automobiles in an area.

If desired, in place of the filter 27 a device for catalytic or glow-plug-type combustion may be provided or, if desired, a non-regenerative system may be used by changing the filter cartridge 28 periodically, although, as said before, this is somewhat less desirable, being more eX- pensive and also more wasteful.

To thise skilled in the art to which this invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the spirit and scope of the invention. The disclosures and the description herein are purely illustrative and. are not intended to be in any sense limiting.

I claim:

1. A device for controlling fuel evaporation and leakage losses when filling an automobile fuel tank having a filling spout from a filling station pump having a nozzle, comprising: vapor seal means for sealing between said spout and said nozzle to prevent leakage of vapors from said tank when it is being filled with gasoline, a vent line extending from said tank, and filter means for withdrawing gasoline vapor from air connected to said gasoline vent line.

2. A device for controlling fuel evaporation and leakage losses from an automobile having a gasoline tank with a filling spout, fuel line, and vent line, said tank being filled from a filling station pump by a nozzle inserted into said filling spout, comprising: seal means for sealing between said spout and end nozzle for preventing leakage of vapors from said tank when it is being filled with gasoline; a gooseneck in said vent line extending a substantial distance above said tank; a collection drop out pot below the highest point in said gooseneck and draining into said tank; a check valve in said vent line; and filter means for withdrawing gasoline vapor from air, connected to said gasoline tank vent line.

No references cited.

MARK NEWMAN, Primary Examiner.

H. BELL, Assistant Examiner.

GOOD-

Claims (1)

1. A DEVICE FOR CONTROLLING FUEL EVAPORATION AND LEAKAGE LOSSES WHEN FILLING AN AUTOMOBILE FUEL TANK HAVING A FILLING SPOUT FROM A FILLING STATION PUMP HAVING A NOZZLE, COMPRISING: VAPOR SEAL MEANS FOR SEALING BETWEEN SAID SPOUT AND SAID NOZZLE TO PREVENT LEAKAGE OF VAPORS FROM SAID TANK WHEN IT IS BEING FILLED WITH GASOLINE, A VENT LINE EXTENDING FROM SAID TANK, AND FILTER MEANS FOR WITHDRAWING GASOLINE VAPOR FROM AIR CONNECTED TO SAID GASOLINE VENT LINE.

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