US3800768A

US3800768A - Apparatus and method for fueling an internal combustion engine

Info

Publication number: US3800768A
Application number: US00229708A
Authority: US
Inventors: J Rhodes; I Ginsburgh
Original assignee: Standard Oil Co
Current assignee: Standard Oil Co
Priority date: 1972-02-28
Filing date: 1972-02-28
Publication date: 1974-04-02
Anticipated expiration: 1991-04-02
Also published as: JPS4899517A; FR2174138A1; DE2309733A1; GB1378276A; FR2174138B3; IT977445B

Abstract

Disclosed is a method and apparatus for operating an internal combustion engine in a manner to reduce hydrocarbon and carbon monoxide exhaust emissions during startup and warmup of the engine. Means are provided for bypassing the engine carburetor and fueling the engine with a gaseous fuel of air and low boiling gasoline components derived from gasoline by bubbling air through the gasoline. After the engine and emission control devices have reached predetermined operating conditions, fuel is supplied to the engine by the carburetor. A novel mixing valve is employed for controlling the air-fuel ratio of the gaseous fuel.

Description

United States Patent 1191 Rhodes et al.

[451 v Apr. 2, 1974 APPARATUS AND METHOD FOR FUELING AN INTERNAL COMBUSTION ENGINE [75] Inventors: Joseph C. Rhodes, Park Forest;

' Irwin Ginsburgh, Morton Grove,

both of 111.

[73] Assignee: Standard Oil Company, Chicago, 111.

[22] Filed: Feb. 28, I972 [21] Appl. No.: 229,708

[52] US. Cl. .l 123/133 [51] Int. Cl. F02m 17/22 [58] Field of Search 123/133, 134, 1 21, 120,

123/136, 180 A, 140 VS; 60/285 [56] References Cited UNITED STATES'PATENTS 3,718,000 2/1973 Walker 60/285 3,483,855 12/1969 Thoma 123/140 VS 3,049,850 8/1962 Smith 123/134 1,051,122 l/1913 Krayer 123/134 2,285,905 6/1942 Cunningham et a1 123/121 3,601,107 8/1971 Rohrbacher 123/136 2,073,282 3/1937 McCarthey 123/133 1,507,533 9/1924 Walker et a1. 123/120 FOREIGN PATENTS OR APPLICATIONS 1,906,907 9/1970 Germany 123/134 Primary Examiner-Laurence M. Goodridge Attorney, Agent, or FirmArthur G. Gilkes; William T. McClain; John J. Connors [57] ABSTRACT Disclosed is a method and apparatus for operating an internal combustion engine in a manner to reduce hydrocarbon and carbon monoxide exhaust emissions during startup and warmup of the engine. Means are provided for bypassing the engine carburetor and fueling the engine with a gaseous fuel of air and low boiling gasoline components derived from gasoline by bubbling air through the gasoline. After the engine and emission control devices have reached predetermined operating conditions, fuel is supplied to the engine by the carburetor. A novel mixing valve is employed for controlling the air-fuel ratio of the gaseous fuel.

8 Claims, 12 Drawing Figures 1 111111! Ill 5/ Pl(Vij8T FUEL INTAKE SYSTEM fi/E ENGINE VP Ill EXHAUST CATALYST SYSTEM EATENTEDAPR- 2 m4 SHEET 1 OF 5 FIG. I

FUEL INTAKE SYSTEM ENGINE V Ill' EXHAUST CATALYST SYSTEM JE.

PATENTEU R 2 I974 SHEET 2 0F 5 PATENTEDAPR 21914- SHEET 6 0F 5 FIG. 9

AIR

. 1 APPARATUS AND METHOD FOR FUELING AN. INTERNAL COMBUSTION ENGINE BACKGROUND By 1975 automobiles will be required to limit exhaust hydrocarbon to 0.41 grams per mile and carbon monoxide to 3.4 grams per mile. At present there is no technology available permitting an automobile to meet these standards when tested according to Federal Emissions Test CVS Ill-I-IC. This test requires a run of about 7 miles in 23 minutes from a cold start at 6886 F. Emission control devices for oxidizing hydrocarbons and carbon monoxide are available but they are not effective until warmed up. Consequently, vehicles equipped with such devices fail the federal test because of hydrocarbon and carbon monoxide emission during the first minute or so of the test. This occurs because during warmup, using a conventional carburetor,.excess gasoline is introduced into the engine by carburetor choking. Eliminating or reducing carburetor choking will substantially reduce emissions, but the driveability of the vehicle will be unacceptable due to stalling or lack of power. Highly volatile fuels, such as natural gas, propane, or gasoline with very low end point temperature, could be used with little or no choking. But all of these have serious drawbacks. Natural gas needs bulky, pressurized storage, and is already in short A TI-IE INVENTION We have invented a novel fueling system which solves this problem. Our system calls for bypassing the conventional carburetor at startup and fueling the engine with a gaseous fuel comprising a mixture of air and low boiling gasoline components (mostly C and C hydrocarbons with some C and C hydrocarbons). This gaseous fuel is clean-burning and does not materi ally impair the driveability of the automobile. Mixing of air and the low boiling gasoline components is carefully controlled to provide an about constant air to fuel ratio which is at about stoichiometric or leaner. This is important in order to minimize hydrocarbon and carbon monoxide exhaust emissions. At predetermined engine conditions, for example at elevated engine or exhaust catalyst temperature, fueling of the engine is turned over to the carburetor. Suitable monitor means sense such predetermined engine operating conditions. An automobile equipped with our systemand known catalytic mufflers will meet the 1975 federal hydrocarbon and carbon monoxide emissions standards. This is achieved with a relatively minor modification of the automobile. The structure, function and advantages of the preferred embodiments of our system are disclosed in the attached drawings and accompanying descriptron.

'ployed in our system.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of our novel fueling system for an internal combustion engine.

FIG. 2 is an exploded perspective view of the mixing valve employed in our system to control the air-fuel ratio.

FIG. 3 is a sectional view of mixing valve taken along line 33 of FIG. 5.

FIG. 4 is a sectional view of the mixing valve taken along line 44 of FIG. 5.

FIG. 5 is a side elevational view of the mixing valve assembled.

FIG. 6 is a schematic view of the air-fuel ratio controller of the mixing valve.

FIG. 7 is a schematic wiring diagram for switching control of fueling between our novel fueling apparatus and a conventional carburetor.

FIG. 8 is a schematic drawing showing one alternate embodiment of our invention.

FIG. 9 is a schematic drawing of another alternate embodiment of our invention.

FIG. 10 is a perspective view of the gasoline tank em- FIG. 11 is a fragmentary view of the top of the air chamber in the tank shown in FIG.- 10;

FIG. 12 is a fragmentary view in cross-section of the. bottom of the gasoline tank in a tilted position.

DESCRIPTION OF PREFERRED EMBODIMENTS GENERAL FIG. 1 schematically illustrates our system 10 for operating internal combustion engine 11 in a way which reduces hydrocarbon and carbon monoxide exhaust ping the gasoline with air. This is the preferred technique for separating low boiling components from higher boiling components, although other separation techniques may be suitable. According to our invention, during startup and warmup, fueling of the engine is accomplished with our fueling apparatus 14. When predetermined engine operating conditions have been attained, then fueling of engine 1 l is accomplished with carburetor 12'.

Our system 10 is shown in the startup mode where carburetor 12 is bypassed. In this mode, fueling apparatus 14 controls the feeding of fuel to the engine. This apparatus 14 includes tank 20 containing gasoline 22,

mixing valve 24 for blending air with the gasoline vapor contained in tank 20, and fuel-line 40 placing valve 24 in communication with engine 11 through fuel intake system 16.

Tank 20 has fuel inlet 21 which includes tube 23 extending about two inches below the top of tank 20. This limits the amount of fuel that can be placed in tank 20 and insures that there will always be space 32 above pors.

Mixing valve 24 includes fuel port 26, air port 28, pressure regulator 42 and air-fuel ratio controller 44. Fuel port 26 is in communication through line 30 with vapor space 32, and air port 28 in communication through

lines

34 and 36 and filter 38 with the atmosphere. Controller 44 provides means for setting at a predetermined ratio the blending of air and fuel. Pressure regulator 42 provides means for maintaining said air-fuel ratio constant while varying the amounts of air and gasoline components being introduced into mixing valve 24. Thus the proper quantity of a controlled, lean gaseous fuel mixture flows through line 40 to the engine despite varying fuel demand. At startup the engine is then fueled with such a gaseous mixture, which is burned in the engine to produce a minimal quantity of hydrocarbon and carbon monoxide even though the engine may be cold. The air-fuel ratio of the mixture will be about stoichiometric or leaner provided acceptable driveability is achieved. Normally this is a ratio ranging between about :1 and about 23:1, preferably about 18:1. This clean-burning fuel is provided at startup, warmup, idling and high speed with our apparatus 14.

Fuel line 40'includes throttle valve 46, ganged together

valves

48 and 50, and flame arrester 52. Under the proper conditions, fuel line 40 may be vented to the atmosphere through valved line 54 or' normally closed outlet 56. Throttle valve 46 controls the flow of fuel through line 40, and this fuel flow is directed into fuel intake system 16 when control valve 47 is closed as shown. The purpose of ganged together

valves

48 and 50 is to insure that an ignitable mixture is trapped in fuel line 40. This assures instant starting.

MIXING VALVE FIGS. 2 through 6 show in greater detail the structure and function of mixing valve 24. Specifically, FIG. 2 shows the principal components of this valve: blocks 60 -62, triangular swinger plate 64, slider plate 66, and cover 68. Cavities in block 60 form fuel chamber 78 and air chamber 80. Tube 70 attached to hole 74 places fuel chamber 78 in communication with vapor space 32 through line 30, and tube 72 attached to hole 76 places air chamber 80 in communication with the atmosphere through

lines

34 and 36 and filter 38.

Block 61 provides a mounting for swinger and

slider plates

64 and, 66, and it includes swinger cavity 82, slider cavity 84, triangular opening 86 and quadrangular opening 88. Securely attached to the apex of swinger plate 64 is pin 90 which has pivot end 92 seated in semicircular cut-out 94 in block 61. Seated swinger plate 64 lies flush against wall 96 of swinger cavity 82 and is free to swing back and forth within this cavity with rotation of pin 90. Swinger plate 64 has sealing appendage 98 which rides in groove 100 as this plate either partially or completely covers

openings

86 and 88 in accordance with plate position. Slider plate 66 lies on top of swinger plate 64 and slides to and fro in slider cavity 84 when arm 102, secured to plate 66, is actuated. Plate 66 lies flush against wall 104 of cavity 84, and arm 102 slides along groove 106 in the perimeter of block 61.

As best shown in FIG. 3, triangular opening 86 and quadrangular .opening 88 may be partially or completely covered depending upon the positions of swinger and

slider plates

64 and 66. Slider plate 66 controls the ratio of the areas defined by openings 86' and 88 and swinger plate position. This ratio determines the ratio of flow through port 26 to flow through port 28. As swinger plate 64 pivots, both triangular opening 86 and quadrangular opening 88 are partially or completely covered. Because of the geometry of these

openings

86 and 88, the ratio of the opening areas will remain constant even though the sizes of these openings change. This follows because the relationship between triangular opening 86 and quadrangular opening 88 is equivalent to the relationship of similar triangles. However, we could, for example, have made these openings equal sized rectangles. But with such design any slight change in the position of slider plate 66 would cause a great change in the ratio of opening areas. Thus it would be difficult to accurately. control the air-fuel ratio. Though we prefer the design shown, alternate designs for controlling the ratio of opening areas could be used. For example, structure similar to the shutter for a camera lens might be suitable.

When the parts of mixing valve 24 are assembled as shown in FIG. 5, block 62 covers block 61, and pin extends through bushing 1 10 (FIGS. 3 and 4) in

blocks

61 and 62, and then through hole 112 in cover 68. Block 62 includes triangular opening 114 and quadrangular opening 1 16 which are coincident to

openings

86 and 88, respectively, with blocks 60-62 bolted together. As shown in FIG. 4, the inside face 1 18 of block 62 includes elongated groove which accommodates arm 102, and shims 122 and 124 which hold the base end of swinger plate 64 snug in cavity 82.

As illustrated by this embodiment of mixing valve 24, fuel port 26 is defined by tube 70, hole 74, triangular openings 86 and 1 l4, and air port 28 is defined by tube 72, hole 76, and

quadrangular openings

88 and 116. Sealing appendage 98 on swinger plate 64, fitting into groove 100, prevents the passage of gases between air port 28 and fuel port 26 until the gases reach chamber (FIG. 2). This chamber 130, formed by a cavity in the outer face of block 62, serves as a blending chamber where air and fuel mix together. Tube 131, projecting from the face of cover 68, places fuel line 40 into communication with blending chamber 130 so that the lean fuel mixture flows from this chamber into the engine.

As shown in FIG. 6, air-fuel ratio controller 44 sets the position of slider plate 66. Controller 44 includes tubular chamber 134 which extends'below the level of gasoline 22, bellows 136, and spring-loaded diaphragm 140. Bellows 136, attached to lower end of chamber 134, communicates through line 138 to the spring side of diaphragm 140. The other side of diaphragm 140 is connected to rod 102 of slider plate 66. Solenoid 142 is attached to the back of bellows 136, and spring 144 is attached between this back and closure plate 146. O- ring 148 is seated adjacent bellows mouth 149, be tween closure plate 147 and open end 1530f tubular chamber 134. When solenoid 142 is de-energized, gasoline flows through open end 153 and fills bellows 136. With the solenoid energized, closure plate 146 snaps to an up position sealing off end 153 of tubular chamber 134. Simultaneously, bellows 136 is extended, as shown in dotted lines, to trap gasoline in the bellows and form a vapor space above this trapped gasoline. The vapor space should be about 4 times as large as the volume of trapped gasoline. This minimizes any effect dissolved air may have on pressure in the vapor space. Springloaded diaphragm 140 responds to the vapor pressure within this vapor space and adjusts slider plate 66 according to this vapor pressure. Consequently, as the composition of the gasoline changes due to seasonal blending or air stripping, and as gasoline temperature varies, slider plate 66 will be moved to different positions to compensate for these changes to maintain the ratio of air to fuel at a predetermined level. For example, if the temperature of gasoline 22 rises, its vapor pressure increases. To maintain the air-fuel ratio constant, plate 66 must be moved to reduce the size of

triangular openings

86 and 114 and increase the size of

quadrangular openings

88 and 116. If vapor pressure decreases, the converse is true. If gasoline 22 has been stripped of most of its low boiling components, its vapor pressure decreases. Consequently, the size of

openings

86 and 114 is reduced and the size of

openings

88 and 116 is increased. Ordinarily, the size of these openings is such that the air-fuel ratio in line 40 ranges between about :1 and about 23:1.

With slider plate 66 in a set condition, the openings permitting air and fuel to flow through control valve 24 must be varied as thedemand for flow of fuel changes with the operation of throttle valve 46. Yet, air-fuel ratio must remain abput constant. We achieve this by moving swinger plate 64 to different positions in re-' sponse to a differential in pressure between atmospheric pressure and pressure in fuel line 40. Pressure regulator 42 senses this differential pressure and maintains pressure drop across

ports

26 and 28 about equal. It achieves this desite v'arying fuel demand and variations in gasoline level in tank 20. Normally, the hydrostatic pressure head in tank is about +5 inches of water.

.As shown in FIGS. 1 and 5, swinger plate 64 is connected through pivoted actuating arm 128 and rod 150 to one side of spring-loaded diaphragm 152 of regulator 42. Arm 128 is pivotally connected at 151 to rod 150. Spring 154 is on the opposite side of diaphragm 152 and normally urges rod 150 to the right, as shown in FIG. 1. This moves swinger plate 64 to a position which completely blocks the triangular and

quadrangular openings

86, 88, 1 14 and 116. At startup, as throttle valve 46 is opened and the engine cranked, a vacuum is created in fuel line 40. When the vacuum pressure within line 40 is about 50 inches of water, the differential in pressure across diaphragm 152 is such that spring 154 is compressed, pulling rod 150 to the left. This moves swinger plate 64 so that

openings

86, 88, 114 and 116 are uncovered, at least partially. By providing sufficient negative pressure, e.g. 50 inches of water, the gasoline head is overcome and air is forced to bubble through gasoline 22 during cranking and slow idling.

As the demand for fuel increases, spring 154 is further compressed and swinger plate 64 is moved such that these openings are further uncovered. As previously mentioned, the ratio of opening areas remains constant, but more fuel mixture flows through the control valve 24. When throttle valve 46 is fully open, the demand for fuel flow is greatest and plate 64 does not block these openings. When fully closed, the demand is the least and plate 64 returns to a position blocking these openings.

To attain controlled mixing of air and fuel, the relative pressure between

ports

26 and 28 remains essentially constant. This is achieved when the pressure drop across air port 28 is about equal to the pressure drop across fuel port 26. However, this cannot be attained in an absolute sense because of the hydrostatic head in tank 20. For example, if the hydrostatic head in tank 20 is +5 inches of water and the vacuum pressure in the fuel line is 50 inches of water there will be a pressure drop across fuel port 26 of -45 inches. In contrast, since air port 28 is in direct communication with the atmosphere, the pressure drop across this port will be 50 inches of water. This ten percent or so difference will not adversely interfere with proper mixing of fuel and air. In this example, spring 154, controlling the actuation of rod 150, must be sufficiently strong so that it will not be compressed by atmospheric pressure until the suction in fuel line 40 is about -50 inches of water. Any spring strength sufficiently great so that the hydrostatic head has a minimal effect on the pressure drop, but not so great that it would interfere with flow of fuel to the engine, is suitable. Hence, despite varying demand for fuel flow and variation in gasoline line level in tank 20, the air-fuel ratio remains about constant.

OPERATION The operation of our fueling system 10 is best understood by considering FIG. 1 in connection with control circuit 16l'shown in FIG. 7. Control circuit 161 controls the positions of

valves

47, 48, 50 and 164, and it includes series-connected switches 166 and 168 which are in parallel connection with switches 170 and 172. These switches,v at startup, are normally closed and they respond to changing operating conditions of the engine. Switch 170 is responsive to the temperature of the catalyst contained in catalytic muffler 174 (FIG. 1 When the temperature of the catalyst reaches a certain level, this switch 170 opens. Switch 168 is responsive to the temperature of the cooling water of the engine. When the cooling temperature reaches about F, a thermocouple senses this condition and causes switch 168 to open.'Switch 166 is a timer switch which remains closed for the first two minutes of engine operation. It then opens automatically. Switch 172 is also a timer switch which'opens automatically after ten seconds. Main control switch 176 is a single-pole, 3-throw switch which is set by the operator. Depending upon its position and the position of switches 166, 168, and 172, induction coil 178 of a master control solenoid is energized. Switch 176 has three positions: an open position at contact 180, an automatic position at contact 182, and a closed position at contact 184. Whenever induction coil 178 is energized, a circuit is completed to close valve 47 and vent valve 164 and to open ganged together

valves

48 and 50, thus turning fueling of the engine over to fueling apparatus 14. Light 186, when lit, signals that the startup mode is operational. Whenever induction coil 178 is de-energized, valve 47 and vent valve 164 are opened, and ganged together

valves

48 and 50 are closed. Vapors trapped between ganged together

valves

48 and 50 vent to the atmosphere or a retention cannister.

FIG. 1 shows our system 10 in the bypass mode with valve 47 in a closed position, blocking carburetor manifold tube 162 immediately above the point where fuel line 40 merges with this tube. Also, ganged together

valves

48 and 50 are in the open position, and valve 164 in vented line 54 is closed. In this mode, air flows through filter 38 and

lines

36 and 34 into, respectively, mixing valve 24 and tank 20. Pressure regulator 42, upon sensing a differential in pressure of about 50 inches of water across

ports

26 and 28 of valve 24, responds to move swinger plate 64 to a position perrnitting flow through mixing valve 24. Because there is a differential in pressure across port 26 significantly greater than the hydrostatic head of gasoline 22 in tank 20, air from line 36 bubbles through gasoline 22 filling space 32 with air-saturated, low boiling gasoline components. This equilibrium gaseous mixture, rich in such gasoline components, flows through line 30 and mixes further with air flowing into valve 24 through air port 28. If the temperature of gasoline 22 varies, controller 44 moves slider plate 66 to the proper position to maintain the air-fuel ratio constant. Also, as fuel demand varies, swinger plate 64 moves to different positions. However, the pressure drop across port 28 is about equal to the pressure drop across port 26. Thus the airfuel ratio remains constant despite varying demand for the flow of fuel as determined by the position of throttle valve 46.

In the other mode, where fueling of the engine is controlled by carburetor 12, fuel pump 188 feeds gasoline through line 190 to float chamber 192 of carburetor 12. A venturi air stream pulls gasoline into manifold tube 162 through line 194. Carburetor 12 includes throttle valve 196 and pump 1 98, actuated by the operator depressing the foot pedal. These conventional carburetor elements govern feeding of gasoline to the engine during this mode. But, when our system is in the bypass mode, a mechanical linkage disconnects the foot pedal and some of these elements so that gasoline will not fill manifold tube above closed valve 47.

ALTERNATE AND OPTIONAL FEATURES An alternate bypass mode is shown in FIG. 8. In this mode, fuel line 40 merges with manifold tube 162 above the carburetors throttle valve 196. This throttle valve 196, operated by actuation of the foot pedal, will then serve to control the flow of fuel to the engine in both modes. However, shutoff valve 200 is provided upstream of the merger point. This valve 200 is closed in the bypass mode, preventing gasoline from being introduced into the system through carburetor 12. In addition, plug 202 is inserted into idle stream line 204, blocking this line and preventing raw gasoline from entering the engine during the bypass mode.

Other features of our invention include drainage of the carburetor float chamber 192 during shutdown, a safety system for fueling apparatus 14, and novel air dispersing system 210 (FIGS. 9 and for fuel tank 20. As shown in FIG. 1, there is valved line 212 connecting float chamber 192 with the upstream end of fuel pump 188. At shutdown, valved line 212 is opened by the deactuation of a solenoid (not shown) permitting gasoline in chamber 192 to flow into theupstream end of fuel pump 188. At startup this solenoid would be reactuated. Since the bypass mode will be governing for a sufficient duration during startup, the fuel pump has time to refill float chamber 192. Thus, when fueling of the engine is turned over to carburetor 12, the carburetor is prepared to inject gasoline into fuel intake system 16. However, because float chamber 192 can be drained and the gasoline returned to a sealed system, gasoline vapors will not escape to the atmosphere, which they would otherwise do if the gasoline were permitted to remain in float chamber 192 above a hot engine.

The safety system includes flame arrester 52 and pressure release plate 222 held snugly against outlet 56 in fuel line 40 by springs 224. If there is a backfire and flame spreads through fuel line 40, flame arrestor 52 will quench this flame before it reaches gasoline tank 20. Although quenching stops the flame reaction, pressure can propagate downstream of flame arrester 52. This pressure forces release plate 222 to lift up and uncover outlet 56, venting the pressure pulse.

FIG. 9 illustrates an alternate embodiment of our fueling system 250 where gasoline 251 in float chamber 252 of carburetor 254 is used at startup as the source of low boiling gasoline components. Preferably, float chamber 252 should be of a large enough size to insure adequate supply of gasoline vapors in vapor space 256 above the liquid level in the chamber. Preferably, this chamber 252 is also insulated from the heat of the engine. In this embodiment, air line 258 extends through the side wall of chamber 252 and terminates below the level of gasoline 251 in the chamber. Fuel pump 260 through line 262 fills chamber 252 with gasoline 251, and float 264 connected by rod 266'to plug 268 senses the level of liquid in the chamber. Plug 268 seals inlet end 270 of line 272, but opens this end so that gasoline circulates through chamber 252 as the liquid level rises. Extending from the top of chamber 252 is fuel line 274 including valve 276. This line 274 places vapor space 256 into communication with carburetor venturi channel 278. Flame arrester 280 preferably is included within this line 274. Air-fuel ratio controller 284, similar to that shown in FIG. 6, senses the vapor pressure of gasoline 251 in chamber 252. Choke plate 282, connected through a diaphragm to controller 284, regulates the size of the opening leading to fuel line 274 in response to the operation of the controller.

- In the bypass mode, air is drawn into the engine through the manifold tube 286 of carburetor 254, some air being drawn through air line 258. This air bubbles from the end of line 258 through gasoline 251 to saturate vapor space 256 with a gaseous mixture rich in low boiling gasoline components. Valve 276 is open, as shown, to place vapor space 256 in communication with venturi channel 278 of carburetor 254. The gaseous mixture flows through this line 274 into the stream of air moving through the venturi channel. Valve 288 in gasoline 290 is closed, preventing fuel from flowing through this line 290 into the manifold tube. As the demand for fuel increases, more air will flow through venturi channel 278 pulling more vapors from line 274. The converse is also true. The choke plate position sets and controls the air-fuel ratio as regulated by controller 284. Thus the air-fuel ratio remains about constant, despite varying fuel demand. After the engine has warmed up, valve 276 is closed and valve 288 is opened, permitting the engine to be fueled by gasoline 251 in chamber 252.

FIGS. 10 through 12 show novel air dispersing system 210 mounted in tank 20. This system includes a plurality of conduits 230-233 which extend to the top corner extremities of tank 20 and place vapor space 32 above gasoline 22 in communication with collection cylinder 234. At the top of cylinder 234 is line 30 leading to control valve 24. At the bottom of cylinder 234 is return line 236 for returning liquids to the tank. When a full tank is tilted relative to the ground, gasoline 22 covers one or two, or even three, of the conduits shown. But there remains at least one conduit in communication with vapor space 32. Any liquid which may make its way into cylinder 234 is returned to tank 20 through line 236.

System 210 also includes, near the tanks bottom, air chamber 240 having perforated top 241. Attached to this top is grid 242 which forms a plurality of samll traps 244. Thus, as shown in FIG. 12, if the attitude of the tank changes and there is a low level of gasoline in the tank, gasoline will be collected in traps 244 so that most of perforations 246 are covered with gasoline. Air introduced through air line 34 fills air chamber 240 and forces gasoline from this chamber and through perforations 246. This achieves uniform dispersion of air throughout gasoline 22 and assures saturation of the air with gasoline.

Tank 20 also includes standpipe 247 which extends a few inches into the tank. This standpipe is connected to fuel pump 188. However, since it extends into tank 20 there always will be some gasoline liquid retained in the tank to serve as a supply of gasoline vapors.

An alternate method of controlling the air-fuel ratio calls for programming the movement of slider 66 as a substitute for controller 44. Inthis embodiment the control of the slider position would be governed by the cranking speed of the engine. Initially, the slider is set to cover the entire fuel port 26. As the engine cranks, the slider is programmed to move at a speed regulated by cranking speed, opening fuel port 26 and closing air port 28. At some point the proper combustible mix is attained and the engine fires. The slider is then advanced a predetermined extra distance to insure good driveability.

ADVANTAGES The principal advantage of our invention is the substantial reduction, achieved at startup and warmup, in hydrocarbon and carbon monoxide exhaust emissions. Our system permits a cold engine to be fueled with a controlled, clean-burning gaseous mixture. Our system is relatively inexpensive to mass-produce and it uses conventional gasoline presently being manufactured. Our system also elminates flooding of the engine at startup. And, since a gaseous mixture is employed, the engine will start quickly even during cold weather.

Repeated cold starts and short trips would eventually result in stripping low boiling components from gasoline 22 in tank 20. Computer analysis indicates, however, that adequate gasoline vapors will be present to meet the demands of normal driving. In the rare case where there would not be adequate gasoline vapors in tank 20, our system 10 could be bypassed or a warning light turned on to indicate that the automobile must be refueled.

Our system also can be adapted to preventescape of vapors to the atmosphere during fueling operations. For example, inlet 21 would be equipped with a seal mechanism so that gasoline vapors would be retained in tank and a fueling nozzle would be inserted into the inlet. The engine would be running and apparatus 14 would be fueling the engine with excess vapors, burning these vapors rather than permitting them to escape to the atmosphere.

Also, since the carburetor float chamber 192 can be drained, another source of hydrocarbon emissions from an automobile is eliminated. The carburetor could be drained with conventional systems; however, it would require an electric motor to pump fuel to carburetor float chamber 192 before startup. This added expense is avoided by our system since during startup our apparatus 14 is fueling the automobile and conventional fuel pump 188 is refilling float chamber W2.

Our system also provides a convenience to the motorist, i.e., if the motorist were to run out of gasoline, of operation in the normal mode as determined by standpipe 247 height, he could manually switch over fueling of the engine to our apparatus 14. The engine would thus run for a few minutes by stripping vapors from gasoline remaining in tank 20. This permits the motorist to either pull off to the side of the road or drive to a nearby service station.

Moreover, our system is safe. The air-vapor mixture in space 32 is what it would be if tank 20 were used in a conventional manner by draining liquid gasoline from the tank bottom and admitting air through a vent to replace withdrawn liquid. Such an air-vapor mixture is too rich to ignite at normal temperatures, e.g., temperatures above F. Heavily stripped gasoline, due

to repeated starts, might at very cold temperatures result in an explosive mixture. But even then the likelihood of an explosion, with normal engine operation, is remote.

' Our system also eliminates carburetor choking. Such Q choking is required during warmup with conventional carburetors in order to introduce into the engine enough low boiling gasoline components to insure starting. Our apparatus 14 used at startup and warmup thus replaces a carburetor choke.

We claim:

1. In combination with an internal combustion engine fueled by gasoline as the sole source of fuel for the engine, and having a fuel intake system for the engine, a carburetor coupled to the fuel intake system and an emission control system for removing hydrocarbon and carbon monoxide from engine exhaust,

first means for separating low boiling gasoline components from higher boiling gasoline components .of the gasoline and mixing said low boiling components with air in a controlled manner to provide a gaseous fuel'having a predetermined air to fuel ratio which is about stoichiometric or leaner, said first means including means for holding gasoline and providing a vapor space above the gasoline, a fuel line in communication with the fuel intake system of the internal combustion engine and said vapor space, the demand for the flow of fuel through said fuel line varying with changing operating conditions of the engine, and means for introducing air into the gasoline and forming in the vapor space a gaseous mixture of air and low boiling gasoline components;

said introducing means including an air port in communication with the fuel line and atmosphere, a fuel port in communication with the fuel line and the vapor space, said ports each having means which vary the size of port openings including a first element for adjusting the ratio of the opening areas in accordance with said predetermined airfuel ratio and a second element for closing said ports until a predetermined negative pressure substantially greater than the pressure of the head of gasoline in the container means has been established in the fuel line, so that air will bubble through the gasoline in the container means, said second element exposing said ports when said predetermined negative pressure has been achieved;

2. The combination of claim 1 wherein the carburetor includes means for draining the carburetor and returning gasoline to a gasoline storage means.

3. Fueling apparatus for an internal combustion engine, comprising:

container means for holding gasoline and providing a fuel line in communication with the fuel intake sysmeans responsive to operating conditions of the ensecond means for bypassing the carburetor during third means operable when the emission control systern has reached a predetermined elevated temperature for discontinuing operation of the second means and switching fueling of the engine over to the control of the carburetor.

a vapor space above the gasoline;

means for introducing air into the gasoline and forming in the vapor space a gaseous mixture of air and low boiling gasoline components;

tern of the internal combustion engine and said vapor space, the demand for the flow of fuel through said fuel line varying with changing operating conditions of the engine; and

gine for controlling the air-fuel ratio in the fuel line so that said air-fuel ratio remains about constant despite the varying demand for flow of fuel,

said controlling means including an air port in communication with the fuel line and atmosphere, a fuel port in communication with the fuel line and the vapor space, said ports each having means which vary the size of port openings including a first element for adjusting the ratio of the opening areas in accordance with a predetermined air-fuel ratio, and a second element which changes the size of said openings but maintains the ratio of said areas about constant despite the varying demand for flow of fuel and variations in gasoline level, said first element being responsive to the vapor pressure of the gasoline in the container means and being moved to different positions with changing gasoline vapor pressures to adjust the ratio of port areas so that said predetermined air-fuel ratio is maintained essentially constant despite changing gasoline vapor pressures, and the second element is responsive to a predetermined differential between atmospheric pressure and pressure in the fuel line and moves to different positions to change the size of port openings while maintaining the ratio of said port areas constant.

4. The apparatus of claim 3 wherein the container means includes a plurality of means for placing the vapor space in communication with the controlling means so that, if one or more of these means is blocked due to fluctuating levels of gasoline, one or more shall maintain communication with the vapor space.

5. The apparatus of claim 4 wherein the container means additionally includes a perforated dispersing chamber near the lower portion of the container means and the air-introducing means is in communication with the chamber so that during operation of the internal combustion engine air fills the chamber and flows through the perforations thereof to disperse bubbles of air throughout the gasoline.

6. The apparatus of claim 5 wherein the perforated chamber has a plurality of traps adjacent thereto which confine gasoline immediately above the perforations in the chamber.

7. The combination of claim 1 wherein the air-fuel ratio ranges between about 15:1 to about 23:1.

8. The combination of claim 1 wherein said first element is responsive to the vapor pressure of the gasoline in the container means and is moved to different positions with changing gasoline vapor pressure to adjust the ratio of port areas so that said predetermined air-fuel ratio is maintained essentially constant despite changing gasoline vapor pressures.

2222 3 UNl'l'l-li) STA'IEFJ' .Ui'i'iifYl OFFICE CERTIFICATE OF CORRECTION Patent No. 3,800,768 Dated April 2, 197

Inventofls) Joseph C Rhodes and Irwin Ginsburgh It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column l, line 53, "closure plate 1 W" should be closure plate 1H6 Column 10, line &3, including means" should be including container means Signed and sealed this 17th day of September 1974. I

(SEAL) v Attest: v

McC OY M. GIBSON JR. C. MARSHALL DANN Attesting Officer 4 Commissioner of vPatents

Claims

1. In combination with an internal combustion engine fueled by gasoline as the sole source of fuel for the engine, and having a fuel intake system for the engine, a carburetor coupled to the fuel intake system and an emission control system for removing hydrocarbon and carbon monoxide from engine exhaust, first means for separating low boiling gasoline components from higher boiling gasoline components of the gasoline and mixing said low boiling components with air in a controlled manner to provide a gaseous fuel having a predetermined air to fuel ratio which is about stoichiometric or leaner, said first means including means for holding gasoline and providing a vapor space above the gasoline, a fuel line in communication with the fuel intake system of the internal combustion engine and said vapor space, the demand for the flow of fuel through said fuel line varying with changing operating conditions of the engine, and means for introducing air into the gasoline and forming in the vapor space a gaseous mixture of air and low boiling gasoline components; said introducing means including an air port in communication with the fuel line and atmosphere, a fuel port in communication with the fuel line and the vapor space, said ports each having means which vary the size of port openings including a first element for adjusting the ratio of the opening areas in accordance with said predetermined air-fuel ratio and a second element for closing said ports until a predetermined negative pressure substantially greater than the pressure of the head of gasoline in the container means has been established in the fuel line, so that air will bubble through the gasoline in the container means, said second element exposing said ports when said predetermined negative pressure has been achieved; second means for bypassing the carburetor during startup of the engine and fueling the engine directly through the fuel intake system with said gaseous fuel, and third means operable when the emission control system has reached a predetermined elevated temperature for discontinuing operation of the second means and switching fueling of the engine over to the control of the carburetor.

3. Fueling apparatus for an internal Combustion engine, comprising: container means for holding gasoline and providing a vapor space above the gasoline; means for introducing air into the gasoline and forming in the vapor space a gaseous mixture of air and low boiling gasoline components; a fuel line in communication with the fuel intake system of the internal combustion engine and said vapor space, the demand for the flow of fuel through said fuel line varying with changing operating conditions of the engine; and means responsive to operating conditions of the engine for controlling the air-fuel ratio in the fuel line so that said air-fuel ratio remains about constant despite the varying demand for flow of fuel, said controlling means including an air port in communication with the fuel line and atmosphere, a fuel port in communication with the fuel line and the vapor space, said ports each having means which vary the size of port openings including a first element for adjusting the ratio of the opening areas in accordance with a predetermined air-fuel ratio, and a second element which changes the size of said openings but maintains the ratio of said areas about constant despite the varying demand for flow of fuel and variations in gasoline level, said first element being responsive to the vapor pressure of the gasoline in the container means and being moved to different positions with changing gasoline vapor pressures to adjust the ratio of port areas so that said predetermined air-fuel ratio is maintained essentially constant despite changing gasoline vapor pressures, and the second element is responsive to a predetermined differential between atmospheric pressure and pressure in the fuel line and moves to different positions to change the size of port openings while maintaining the ratio of said port areas constant.