US3838673A

US3838673A - Two-stage cold start and evaporative control system and apparatus for carrying out same

Info

Publication number: US3838673A
Application number: US00295029A
Authority: US
Inventors: S Csicsery; B Mulaskey
Original assignee: Chevron Research and Technology Co
Current assignee: Chevron USA Inc
Priority date: 1972-10-04
Filing date: 1972-10-04
Publication date: 1974-10-01
Anticipated expiration: 1991-10-01

Abstract

As cold start is initiated in a spark-ignition internal combustion engine, lower molecular weight constituents of a fullrange gasoline are selectively eluted. In accordance with the present invention, the elution system includes a two-stage adsorbent bed of adsorbent material, forming first and second parallel elution zones within a cannister assembly in selective fluid contact with the full range gasoline under control of a valve and conduit network. The first zone terminates in fluid contact with the fuel well of the carburetor of the engine. The second zone terminates adjacent the air filter of the air intake system. The valve and conduit network is fitted with an additional valve metering unit at the second zone to allow only a metered amount of gasoline to enter, say as a function of temperature. A vapor emission control system can also be housed within the cannister assembly and undergo selective operation to prevent escape of vapor emissions originating from within the carburetor and gasoline tank.

Description

United States Patent Csicsery et a1.

Oct. 1, 1974 [75] Inventors: Sigmund M. Csicsery, Lafayette;

Bernard F. Mulaskey, Fairfax, both of Calif.

[73] Assignee: Chevron Research Company, San

Francisco, Calif.

[22] Filed: Oct. 4, 1972 [21] Appl. No.: 295,029

[52] US. Cl 123/l87.5 R, 123/3, 13/123,

[51} Int. Cl. F02m 1/16, F02m 27/02 [58] Field of Search...l23/l79 G, 3, 180 R, 187.5 R,

[56] References Cited UNITED STATES PATENTS 1,164,931 12/1915 Clairmont 123/l87.5 R

1,490,192 4/1924 Anderson... 123/127 2,704,536 3/1955 Edwards l23/l87.5 R

3,221,724 l2/l965 Wentworth 123/136 3,635,200 l/l972 Rundell et al. 123/3 3,688,755 9/1972 Grayson et al 123/3 Primary Examiner-Charles J. Myhre Assistant Examiner-W. H. Rutledge Attorney, Agent, or Firm-R. L. Freeland, Jr.; H. D. Messner [57] ABSTRACT As cold start is initiated in a spark-ignition internal combustion engine, lower molecular weight constituents of a full-range gasoline are selectively eluted. In accordance with the present invention, the elution system includes a two-stage adsorbent bed of adsorbent material, forming first and second parallel elution zones within a cannister assembly in selective fluid contact with the full range gasoline under control of a valve and conduit network. The first zone terminates in fluid contact with the fuel well of the carburetor of the engine. The second zone terminates adjacent the air filter of the air-intake system. The valve and conduit network is fitted with an additional valve metering unit at the second zone to allow only a metered amount of gasoline to enter, say as a function of temperature. A vapor emission control system can also be housed within the cannister assembly and undergo selective operation to prevent escape of vapor emissions originating from within the carburetor and gasoline tank.

10 Claims, 10 Drawing Figures f 26 fi i smaors PAIHEnnm mu TWO-STAGE COLD START AND EVAPORATIVE CONTROL SYSTEM AND APPARATUS FOR CARRYING OUT SAME RELATED APPLICATIONS Applications filled simultaneously with the subject disclosure which are assigned to a common assignee and containing common subject matter but claiming orative emission control of a spark-ignition internal combustion engine and has for an object the provision of a simple and effective cold start and evaporative control system for use in such engine i. for selectively eluting from a full range fuel flowing to the engine only the lower molecular weight constituents at cold start so as to allow quick starting of the engine without excessive amounts of unburned hydrocarbons appearing at the exhaust as well as ii. for adsorbing evaporative emissions from the gasoline tank and carburetor bowl when the engine is not operating.

Higher molecular weight constituents adsorbed during cold start and/or light, evaporative emissions adsorbed during the disabled cycle of the engine are purged from the system only after the engine has been warmed and the full range fuel utilized.

During cold start of spark-ignition internal combustion engines, the fuel-air ratio is generated by the airfuel intake system, say a conventional carburetion system. At cold start, the air-fuel ratio can be varied (enriched) to assure adequate amounts of lower molecular weight constituents of the fuel at the intake manifold. By operation of a plurality of interrelated well-known parts, the higher molecular weight constituents become more easily vaporized to form combustible vaporfuel/air ratios to allow starting of the engine even at low operating temperatures. However, since remaining higher molecular weight constituents are not oxidized even if the start is rapid, such remaining constituents contribute to the formation of unburned hydrocarbons at the exhaust.

Although a more volatile fuel having a lower boiling point, would permit faster starts and warmup and reduce exhaust pollutants, including unburned hydrocarbons and carbon monoxide emissions, experience shows that full range engine performance using the distinct inventions, include:

Title lnventor(s) Serial No.

Single-Stage Cold Start and Sigmund M. 295,028 Evaporative Control Method and Csicsery Apparatus for Carrying Out Same Cold Start Method and John F. Senger 295,041 Apparatus for Carrying Out Same Fuel lnjection Cold Start and Sigmund M. 295,040 Evaporative Control Method and Csicsery Apparatus for Carrying Out Same Two-Stage Fuel lnjection Cold Sigmund M. 295,030 Start Method and Apparatus for Csicsery and Carrying Out Same Bernard F.

Mulaskey The present invention relates to cold starting and evapmore volatile fuel would be adversely affected. In this regard, fuel consumption would be greatly increased over all ranges of driveability.

In accordance with the present invention, rather than use a more volatile fuel under a multiplicity of operating conditions of a spark-ignition internal combustion engine (particularly during cold start), lower molecular weight constituents of a full-range gasoline are selec tively eluted as cold start is initiated by the driver. The elution system includes a two-stage adsorbent bed of adsorbent material, forming first and second parallel elution zones within a cannister assembly in fluid contact with the full range gasoline. The adsorbent materialusually in pelletized formwith the first elution zone is preferably housed within a tubular means disposed within the cannister assembly, the tubular means being positioned within a much larger shell housing in fluid contact with a valve and conduit net work. Entry of the gasoline is initiated by the valve and conduit network under control of a controller circuit.

Within the second elution zone, the valve and conduit network is fitted with an additional valve metering unit in parallel with the first elution zone which allows only a metered amount of gasoline to enter as a function of temperature. A circumferentially extending air entryway of approximately the shell housing dimen sions is formed near the 'rear end of the second elution zone, the nozzle of the valve metering unit terminating adjacent the air entryway. As gasoline enters via the nozzle and mixes with the air, it is quickly carried through the second elution zone as selective retardation of the higher molecular weight compounds occurs. Due to the velocity of the accompanying air as well as the presence of openings within a screen at the remote, exhaust end of the second elution zone, the lighter low molecular weight constituents are caused to be broken into a fine atomized spray. The atomized spray contains both liquid and vapor phases of the lighter constituents, and is readily flowable through the air filter of the air intake system of the engine into the carburetor. At the carburetor, the cold start fuel constituents from both first and second elution zones are mixed together with air to form a highly combustible cold start air-fuel mixture.

Construction of the cannister assembly can vary. Preferably the arrangement within the first elution zone resembles that provided for a shell-and-tube heat exchanger whereby tube-side gasolineduring cold start-passes through the tubular means packed with the adsorbent material (single pass percolation). Within the second elution zone, the construction of the cannister assembly includes a housing integrally contacting the shell housing of the first elution zone, with the aforementioned entryway disposed therebetween. While the absorbent materal therein can be similar to that used in the first elution zone, or may be different, as explained below, it is always retained within the housing. Selective retardation of the high molecular weight compounds, vis-a-vis the lighter components occurs so that, during start up, only the light constituents pass to the carburetor, for later consumption within the combustion chambers of the engine. Since the starting cycle of an internal combustion engine is quite short, say from 1 to 15 seconds and the residence time for the heavier compounds within the elution zone is l to 2 orders longer say from 1 to 3 minutes, the latter compounds remain selectively adsorbed with both the first and second parallel elution zones.

Preferably, but not necessarily, the present invention has additional utility in preventing evaporative emissions originating within the fuel well of the carburetor and/or within the gasoline tank from escaping into the atmosphere. In this aspect of the invention, the escape of large amounts of hydrocarbon fumes and vapors into the atmosphere from a spark-ignition internal combustion engine in an inoperative state, is acknowledged as being a serious environmental problem, especially within large cities. In this regard, studies indicate that up to percent by volume of the total vapors admitted into the atmosphere, originate from evaporative emissions from spark-ignition internal combustion engines. Governmental bodies are attempting to satisfy emission regulation in cooperation with industry; for example,

California Motor Vehicle Pollution Control Board has proposed the following standards for control of evaporative emissions: 2 grams per hot soak from the carburetor fuel well and 6 grams per day from the fuel tank under standard operating conditions. In this regard, the present invention can be selectively, but no necessarily, operative during such time periods to adsorb such evaporative emissions and prevent their escape into the atmosphere by arranging the first elution zone so-as to provide space between the tubular means and the shell housing. Into that space can be inserted an adsorbent maIeriaL'preferably of the nonpolar type, which form an adsorptive capture zone for use in preventing escape of evaporative emissions into the atmosphere when the engine is in an inoperative state.

The associated valve and conduit network and the controller circuit can place both the elution and capture zones of the cannister assembly in fluid contact with other relevant fuel system components as required; for example, after the engine has started and warmed up both the elution and capture zones can be purged of adosrbed constituents (adsorbates) by passing shell side gases (either full or partial engine air or manifold exhaust gases) through these zones. Thus, not only is the present invention able to rapidly elute low molecular weight fuel constituents at cold startup, but the other adsorbed fuel components can be automatically desorbed without formation of excessive amounts of pollutants at the exhaust.

Although the prior art has suggested both polar and non-polar adsorbent materials for use in vapor recovery systems, there has been no suggestion of using adsorbent materials in an elution system for selectively eluting from a full-range gasoline, only light, low molecular weight components thereof, to assure a smooth pollution-free start of a spark-ignition internal combustion engine.

Further objects, features and attributes of the present invention will become apparent from a detailed description of several embodiments to be taken in conjunction with the following drawings in which:

DESCRIPTION OF THE FIGURES interconnected between a cold start evaporative emission system of the present invention, said cold start evaporative control emission system including a cannister assembly housed within the air intake line of the air cleaner assembly under regulation of a valve and conduit networks controlled by a controller circuit;

FIG. 2 is a partial cutaway of the cannister assembly of FIG. 1;

FIGS. 3 and 4 are section views taken along lines 33 and 4-4 of the cannister assembly of FIG. 2;

FIG. Sis a schematic view of another embodiment of the present invention illustrating a typical carburetor and air cleaner assembly in which the cannister assembly including first and second parallel elution zones is mounted by means of a platform attached to the tire wall of the engine compartment;

FIG. 6 is a plan view of the cannister assembly and air cleaner assembly of FIG. 5 and illustrates the position of a valve metering unit aflxed to an outer housing of the cannister assembly;

FIG. 7 is a fragmentary view of a metering pin of the valve metering unit of FIG. 6;

FIG. 8 is a partially schematic view illustrating an alternate embodiment by which air can be heated to an elevated temperature to better desorb the cannister assembly of FIGS. 1 and 5;

FIG. 9 is a fragmentary view of the valve and conduit network of FIGS. 1 and 5 illustrating the position of the valve network after cold start has been achieved and the engine is at running temperature so that the cannister asembly can be desorbed by passing gases in heat transfer contact therewith:

FIG. 10 is yet another fragmentary view of the valve and conduit network of FIGS. 1 and 5 illustrating the position of the valve network when the engine is in an inoperative state.

Referring now to FIG. 1, there is illustrated an engine fuel system 10 connected to an engine intake manifold 11 of a spark-ignition internal combustion engine (not shown). Fuel system 10 of the present invention includes an air intake system 12, a carburetor 13, a fuel intake system 14, that includes cold start-evaporative control system 15 of the present invention.

To form a combustible air-fuel mixture, air enters by way of air intake system 12, say by way of air inlet line 16a, and is filtered at an air filter interior of an air filter housing 160, before entry into carburetor l3. Carburetor 13 includes a throttle valve 18, a fuel well 19, and a discharge nozzle 20. Fuel well 19 contains a metered quantity of gasoline to be mixed with air passing discharge nozzle 20 and to be passed through intake manifold 11 into the engine combustion chambers (not shown) where combustion occurs. Supplying fuel well 19 with a metered quantity of gasoline is by means of fuel intake system 14. Fuel intake system 14 includes a gas tank 23 containing a reservoir of full-range fuel (i.e., a full-boiling gasoline), a fuel pump 24 and cold start-evaporative control system 15 of the present invention. Cold start-evaporative control system 15 includes a valve and conduit network 25 in fluid contact with the discharge side of fuel pump 24 but under operative control of controller circuit 26. A cannister assembly 27, see FIG. 2, mounted adjacent to the air intake system 12, say within air inlet line 16a, is likewise an element of the cold start system 15 as noted below.

It should be noted that carburetor 13 has been modified to exclude from operation a choke valve so that the enrichment of the fuel-air ratio is performed solely by the cold start-evaporative control system 15 of the present invention. Briefly, with reference to FIG. 2,

cannister assembly 27 is seen to include two parallel sections: a forward section resembling a conventional but scaled down tube-and-shell heat exchanger generally indicated at 27a, and a rear section 27b including a valve metering unit 90. An elongated valve gate 91 interior of common housing 22 of the sections controls internal air flow between the forward and rear sections 27a and 27b, while an air entryway 92 of the same dimensions as and integral with the common housing 22 control external air flow into the rear section 27b via a swedged ribbon of openings 95. In the present aspect of the invention, not only can light low molecular weight components (liquid phase) be conveyed to the fuel well 19 of the carburetor 13 through operations of forward section 27a, but also an atomized spray of such components (both liquid and vapor phase) can be si' multaneously eluted through ports 96 of screen 97 of rear section 27b. As is readily apparent, provision of a combination of atomized spray and liquid cold start fuel mixed at the carburetor assures rapid cold start of the engine under a variety of operating conditions without the formation of pollutants at the exhaust.

Valve and conduit network 25 of FIG. 1 is seen to include cold start inlet and exit valves 25a and 25b, respectively controlled mechanically by relay means 26a of controller circuit 26 through transducer 26d and electrically through bimetal temperature switch 26b, ignition switch 26c and battery 26f. A second relay 26e of controller circuit 26 is seen to control operation of evaporative emissions control valve 25c of valve and conduit network 25 through mechanical transducer 26g. Transducers'26d and 26g convert rectilinear travel of the relay means 26a and 26e to the rotational motion.

COLD-START EVAPORATIVE CONTROL SYSTEM 15.

As indicated with reference to FIG. 1, during cold start of a spark-ignition internal combustion engine, a full-range fuel, i.e., a full-boiling gasoline, having both low and high molecular weight constituents, is conveyed from gas tank 23 through fuel pump 24 into valve and conduit network 25, and thence to cannister assembly 27, (FIG. 2). Although a full-boiling gasoline enters the cannister assembly 27, in accordance with present invention, due to selective retardation of heavier components, only lightweight constituents are eluted during cold start. Such selective retardation during the initial one-three minutes of the starting cycle of the internal combustion engine is achieved based on operational characteristics of parallel first and second elution zones 28 and 28' formed within the cannister assembly 27. Since the nature of the

elution zones

28 and 28 is based on functional characteristics of adsorbent materials, in general, and of polar and nonpolar type adsorbent materials, in particular, a brief discussion of adsorbtion systems is believed to be in order and is presented below with reference to FIG. 2.

Essentially, the first and second elution zones 28 and 28' form parallel columns of parallel frontal analysis chromatagraphs (solution adsorbtion) as classified in accordance with Kirk-Othmer Encyclopedia of Chemical Technology, 2nd Ed., Volume 5, page 418. In accordance with Kirk-Othmer op. cit., such classification is essentially based on the nature of the mobile phase of the system percolating through an adsorbent material. In the case at hand, within the first elution zone 28 fullboiling gasoline enters by way of inlet conduit 33.and percolates through polar adsorbent materal 34 packed within the tubular means 31. Note at the outlet conduit 36, the order of elution is a function of the order of polarity of the constituents of the full range gasoline since the individual molecules of the high molecular weight constituents within the tubular means 31 shuffle at a slower rate between the mobile and stationary phases than do the lighter constituents. Within the second elution zone 28', the full-boiling gasoline is seen to have parallel simultaneous entry into second elution zone 28' by way valve metering unit 90. Adsorbent material 34 retained within common housing 22, provides at end wall screen 42 an identical order of eluted products as polar adsorbent 34 with first elution zone 28. Within the elution zone 28, separation occurs because of the polarity, nonpolarity groupings of these constituents whereby different relative velocities are imparted to the individual molecules of the groupings. The least strongly adsorb low molecular weight liquid components elute first as a group followed by a second grouping containing say both the low and high constituents and so forth until all constituents have appeared. Within the elution zone 28, separation is apparently not, primarily, a function of polar interaction since both polar and non-polar materials can be used to form the adsorbent material 34.

Residence time of the low molecular weight components within the

elution zones

28 and 28 is a function of many factors including the length'of the elution zones as well as the pressure drop during percolation through the

adsorbent materials

34 and 34, respectively. However, the residence time of the heavier components is much longer within each zone, usually in a range of 13 minutes. However, care ought be exercised in this regard. The flow rate of the mobile phase must be slow enough to allow maximum transfer of the molecules of the heavier constituents into and from the stationary and mobile phases. Since selective retardation of the heavier constituents is quite long, say l-3 minutes, while the typical starting cycle of a modern engine can be quite short, say from 1 second up to l5 seconds except when problems of starting occurs), the heavier constituents remain adsorbed within the elution zone 28 and 28' after the engine has started. This proposition assumes of course that the

adsorbent material

34 and 34 are of a compatible polar classification.

CLASSIFICATION OF ADSORBENT MATERIAL 34 AND 34' As previously mentioned, competition for the high molecular weight groupings of the full-range fuel has been found in the forward elution zone 28 to be dependent on its selective interaction with the adsorptive material 34. Le, the degree of interaction (between the material 34 and the more polar heavier constituents of the full-range fuel) has been found to be directly related to the magnitude of polarity of the adsorptive ma-' terial. In accordance with the present invention adsorptive material 34 should be polar and preferably selected from following non-exclusive listing of popular polar adsorptive materials, with silica gel being somewhat preferred:

Polar Adsorptive Materials Remarks Silica gel Alumina ActivatedPreferrcd Barium sulfate Calcium carbonate Glass Resins and plastics Quartz Titanium dioxide Metallic oxide Zeolites (sieves) Sil X Solid Support Material Coated with Liquid Adsorbers such as chemically bonded liquids. (Eg, Durapak; solids coated with V Octadecyl Silane, Fluoro-cthcts, etc.)

Ion-exchange only Commonly used in Liquid-Liquid Partition Chromatography Non-Polar Adsorbent Material Remarks Charcoal Charcoal blacks Graphite Resins and plastics Paraffins Stibnite Talc Organic only Metallic only The elution zones 28 and 28' can be formed of adsorbent material in granular, pellitized or powdered form. Preparation is straight forward: the adsorbent material should be calcined, acid and base washed, neutralized, and size graded prior to insertion within the cannister assembly 27, say along lines set forth in Kirk-Otlmzer op. cit., Volume 1 at page 460. Since as previously mentioned, the flow rate of the full range gasoline within the elution zones 28 and 28' must be slow enough to allow maximum transfer of the molecules of the heavier compounds into and from the stationery and mobile phases, the size of the

adsorbent material

34 and 34 should be such as to minimize the pressure drop across a cannister assembly 27 without adversely affecting its ability to adsorb these constituents. In this regard, an elution zone having about a l-liter capacity filled with activated alumina of 8 by 14 mesh has been found to adsorb from 200-300 ml. of high molecular weight constituents while yielding about 400 to 500 ml. low molecular weight constituents in the first initial minutes of the cold starting operation. In addition to activated alumina, within the forward zone 28, it has been found that polar gels, such as silica gel, titania gel, zirconia gel, and alumina gel, Fullers earth, bentonite, diatomaceous earth, forisil, attupulgus, and any other polar adsorptive materials are also useful in carrying out that aspect of the present invention. However, in some cases, non-polar materials may be substituted without undue loss in effectiveness. In this regard, non-polar materials listed hereinbefore are appropriate.

CANNISTER ASSEMBLY 27.

Construction of the cannister assembly 27 varies with the type of mounting required to attach the cold startevaporative control system 15 adjacent to air intake system 12. In FIG. 2, cannister assembly 27 is seen to include forward and rear sections 27a and 27b mounted within the intake air line 16a of the air intake system 12. The overall dimensions of the cannister assembly 27 thus must be minimum so as to allow sufficient air to bypass into the carburetor 13. To accomodate the required volume of adsorbent material constituting the elution zones 28 and 28' (FIG. 2), the common housing 22 may have to be correspondingly ultralong. Within the forward section 27a support of tubular means 31 can be brought about by welding radial supports 37 to the side wall of air line 16a to which

cold start conduits

33, 36 as well as evaporative conduit 38 are attached. Within the rear section 27b, support of the common housing is by way of inlet conduit 94. Since the forward and rear sections have essentially individual operational characteristics, each section will now be discussed in sequence.

FORWARD SECTION 27a.

Tubular means 31 is seen to be concentric of common shell housing 22 and includes

supports

40 and 41 at respective ends thereof. Each

support

40 and 41 has peripheral edges in contact with the shell housing 22. Each

support

40, 41 also includes a central plug zone in plugging contact with the central tubular means 31 as well as an intermediate zone 43 (See FIGS. 3 and 4) including a series of ports 44 in registry with a modified parallelpipedonic spacing existing between tubular means 31 and the shell housing 22 wherein adsorbent material 45 is supported. Adsorbent material 45 located in the aforementioned space constitutes a vapor adsorption zone, generally indicated at 46 (adsorption capture zone). In this aspect of the invention, deactivation of ignition switch 26c (of FIG. 1) deactivates relay 26a causing rotation of the vapor control valve 250 to the position shown in detail in FIG. 10. The fuel well 19 and the gas tank 23 of FIGS. 1 and 5 are thus placed in fluid contact with the vapor adsorption zone 46. Note that at the shell side exterior of the central tubular means 31, within zone 46, the atmosphere is permitted to enter at will but is frustrated to exit by operation of valve gate 91. During cold start, the shell-side air is at about the same temperature as the fluid interior of the tubular means 31, so little heat is transferred between the two fluids.

REAR SECTION 2712.

Note that tubular section 31 of the forward section 27a of FIG. 2 does not extend into the rear section 27b but terminates well forward of end wall screen 42. However, the elution zone 28 defined by adsorbent material 34 within the tubular means 31, is continued in the rear section 27b. In more detail within the interior of common housing 22 (preferably of rectangular cross section, see FIGS. 6, 3 and 4) the rear section 27b is provided with adsorbent material 34' forming the second elution zone 28'. The adsorbent material 34' is the preferably of the same polar type as the absorbent material 34 within tubular means 31 of the forward section 27a, as previously mentioned but can be different if desired.

Atop the common housing 22 adjacent rear section 27b, is the valve metering unit 90. As previously explained, with reference to FIG. 1, the valve metering unit 90 has an inlet conduit 94 connected to the elution zone 28'.

Valve unit 90 also has features best illustrated with reference to FIG. 5. As indicated, the valve unit 90 includes conduit 101 connected at T-junction 103 to the conduit 33 in series with cold start inlet valve 25a of valve and conduit network 25. Thus when inlet cold start valve 25a is positioned as depicted in FIGS. 1 and 5, not only can full-range fuel enter forward section 27a but also such fuel simultaneously enters rear section 27b via the T-junction 103, conduit 101 and valve metering unit 90.

The amount of full-range fuel metered into the elution Zone 57 by the valve metering unit 90 is a function of air temperature. Now in more detail, the valve metering unit 90 is seen to include a chamber 104 into which is positioned a bimetallic diaphragm 105. The diaphragm 105 is attached, at its outer edge, to the side walls of the chamber 104 and has a more central location in engagement with enlarged head 106 of a metering pin 107. The spring force provided by the diaphragm 105 is seen to be in opposite direction to the spring force provided by compressions spring 108. Compression spring 108 is seen to be mounted about boss 109 at an end wall of the chamber 104. Boss 109 is also seen to be provided with an opening 110 into which the metering pin 107 is slideably mounted. As temperature changes occur as sensed by bimetallic diaphragm 105, relative movement of the diaphragm causes corresponding movement of the metering pin 107 relative to the opening 110.

Intersecting opening 110 at a right angle is passageway 111. Passageway 111 has an upper inlet port in fluid contact with the conduit 101 and an exit port in fluid contact with metering pin 107.

FIG. 7 illustrates metering pin 107 in more detail. As indicated, the pin 107' consists of an elongated shank portion 112 tapered at a remote end to form a reduced segment 113. At the opposite end, the shank portion 112 is seen extending into contact with the enlarged head 106. Reduced segment 113 is seen to be swedged as a function of length. That is to say, the reduced segment 113 is reduced in diameter from a beginning section 118 to a mid-portion section 119 and then is allowed to increase in diameter until a maximum is reached at end section 120. Accordingly, the amount of gas which can pass into the elution zone 28' is dependent upon whether or not minimum section 119 or beginning section 118 is in registry with passageway 111, i.e., when the pin 107 is as depicted in FIG. 5.

Referring again to FIG. 5, as the temperature changes, it is apparent that the changes in pin location of metering pin 107 relative to passageway 111 meters gasoline into elution zone 57 as a function of tempera.- ture. As the gasoline enters the elution zone 57' in liquid phase, percolation through the elution zone 57 is initiated. Since the absorbent material 56 is of the same polar characteristics as the material 34 within the elution zone 28 of FIG. 2, selected retardation of the aromatic constituents likewise occurs. In the manner as previously explained, air entryway 92' is provided with a swedge band of openings 95' positioned not to interfere with the operation of valve gate 91.

Vacuum in the intake manifold causes air to flow through the radial openings 95 and thence through the elution zone 57' in the accompaniment of the percolating full-range fuel. Due to the velocity of the accompanying air as well as the presence of openings .96 of screen 97 causes the eluding paraffinic constituents at the exit of the rear section 27b to be broken up into a fine atomized spray (atomized vapor). The atomzied spray consists essentially of low molecular weight constituents both in liquid and vapor phases in the accompaniment of air. The fine atomized spray is then drawn through the air filter 16b of the air intake system into the carburetor 13. Due to the velocity of the accompanying air through the rear section 27b, the resulting atomized spray undergoes very little condensation.

It should be noted that during cold start, springloaded gate 91 between the forward and rear sections 27a and 27b, prevents purging of the forward and rear sections 27a and 27b, prevents purging of the forward section 27a. However, as manifold pressure substantially changes indicating full-load operations have begun, the spring loaded gate 91 swings from the position indicated in solid lines in FIGS. 1 and 5 to the positions indicated in phantom line. In that way, engine air (full or partial) can flow through the forward and rear sections 27a and 27b to allow a purging of adsorbed materials.

In FIG. 5, the support of the forward and rear sections 27a and 27b differs markly from that of FIG. 1. The cannister assembly 27 of FIG. 5 is seen to be mounted by common shell housing 22 to a platform 51 which in turn is attached to a firewall (not shown) of an engine compartment. Additional space afforded by the platform 51 allows for a more complex constructural design of the forward section 27a. Instead of constructing tubular means 31 of a single tube as depicted in FIG. 1, a series of upright tubular means 52 can be provided to carry the gasoline entering inlet chamber 53 along a series of sinusoidal passes through the interior of the forward section 27a, such passageways resembling those provided in a conventional tube-and shell heat exchanger. The series of passes made by the gasoline are indicated by arrows 54 while dotted arrows 54' indicate the direction of gas phase flow. In the depicted arrangement, tube-side gasoline is conveyedduring cold starting within the forward section-through the tubular members 52 via inlet chamber 53 (multipass percolation) through adsorbent material 56 to intermediate chamber 65 and thence to exhaust chamber 55. Due to increased total length of the tubular members 52, resulting elution zone 57 is likewise greatly enlarged over that depicted in FIG. 2.

The rear section-27b is similar to that depicted in FIG. 1, and provides the elution zone 57' comprising adsorbent material 56' similar to material 34 retained with elution zone 28 of FIG. 2. Retention of the adsorbent material 56' in elution zone 57 is seen to be provided by screens 42' and 97'.

Further constructural features of the embodiments depicted in FIG. 1 and FIG. 5 are readily apparent. For example, both in FIGS. 1 and 5, the common shell housing 22, is seen to be rectangular in cross-section whereby the assembly forms a parallelepipedon. As illustrated in FIG. 6 the shell housing 22 of the forward section 270 is also seen to include

end walls

58 and 59. End wall 58 includes a series of ports 60 to allow selective entry of hot, exhaust gases via conduit 64 into an adsorptive vapor capture zone generallyindicated at 61 exterior of tubular member means 52 but interior of shell housing 22. Within the vapor capture zone 61, adsorbent material 62 is supported. At the opposite end, the common shell housing 22 is also seen to attach by way of fasteners to the air cleaner housing 16b. Such attachment is oriented such that the ports 96 are in fluid registry with holes in the air cleaner housing 1612.

Although the embodiment depicted in FIG. 1 utilizes full or partial engine air warmed to a high temperature for this purpose, it should also be noted that embodiment of FIG. 5, contemplates utilization of gases from the exhaust manifold to purge with the elution and vapor adsorption zones of adsorbed constitutuents.

After the engine has started and warmed, the cold start exhaust and inlet valves a and 25b return to relaxed positions depicted in FIG. 9, and the fuel intake system switches over to full utilization of the full-range gasoline. That is to say, fuel conveyed from fuel pump 24 passes via conduit 87a to inlet valve 25a and thence from U-shaped conduit 87b and exhaust cold start valve 25b to the fuel well 19. With the utilization of full-range gasoline (and corresponding increases in manifold pressure), the elution zone of the forward section 27a as well as the vapor zones within the fuel well 19 and gas tank 23 can be placed in fluid contact with the carburetor 13 by operation of exhaust start valve 25band evaporative control valve 25c. The elution zone'can be connected via

conduits

36, 88a and 88b (connected to respective ports of valve 25b of FIG. 9)

to the carburetor 13; the fuel well 19 via conduit 83 and valve 250 can be also placed in fluid contact with the conduits 88a and 88b, as can the gas tank 24 via conduit 84 and valve 250. The elution zone of rear section 27b is always in fluid contact with the carburetor 13 via the air intake system 12. In that way, as desorbtion of the adsorbed compounds occurs, say, as warmed gases are conveyed in heat transfer contact with the elution zones, and the compounds are swept into the carburetor 13, there can be a simultaneous conveyance of evaporative emissions if any, from fuel well 19 and gas tank 24. With the desorption of the heavier compounds within the first and second elution zones it should also be pointed out that vapors captured within the adjacent adsorptive capture zone of the cannister assembly can likewise be purged. The captured evaporative emissions pass directly into the air intake system 12 and thence to the carburetor 13, in the manner of desorbed materials from the elution zone of the rear section 2712.

In FIG. 5, the conveyance of the hot exhaust gases from the exhaust manifold is under control of additional electrical circuitry (not shown) of the controller circuit 26. When the temperature of the exhaust manifold reaches a selected temperature, a relay (not shown) is tripped to pass the purging gases through the cannister assembly 27 via conduit 64. The desorbed materials within the elution and vapor adsorption zones of the cannister assembly 27 are ultimately consumed within the combustion chambers of the engine.

Where the aromatic compounds within the elution zone of the cannister assembly 27 have relatively high boiling points, too high in fact to be renewed by passing adjacent engine air in heat transfer contact with the elution zone, the embodiment depicted in FIG. 5 is especially useful. In this regard, the adsorbent material 56 and 56' of FIG. 5 can be simultaneously renewed using the hot exhaust gases as the purging agent. If the temperature of such exhaust gases range from 700 F to about 800 F only a relatively short desorption time is required. Temperatures of the adsorbent beds comprising the elution zones can be a range from 400500 F with about 450 F being a satisfactory operating temperature.

Generally desorption time is quite short for such range setting. say being from about 2-l 2 minutes in duration. The resulting desorbed high molecular weight compounds then pass through the air intake system and carburetor 13 to the combustion chambers where they are consumed.

Capture of evaporative emissions within vapor adsorption zones of the cannister assemblies 27 of FIGS. 2 and 5 can also be desorbed utilizing the purging gases in the manner described above. It should be noted that the captured adsorbates within the vapor capture zone are mostly light low molecular weight constituents. According, the adsorbent material indicated at 45 in FIG. 2 and at 62 in FIG. 66 should be nonpolar. In this regard, the following non-polar adsorbent materials are preferred in carrying out this aspect of the present invention.

Non-Polar Adsorbent Material Remarks Organic only Metallic only FIG. 8 illustrates yet another mode for desorbing the elution and vapor adsorption zones of the cannister assembly of FIGS. 2 and 5. In accordance with the illustrated embodiment, engine air is heated by passing the air adjacent to exhaust manifold 70 and thence through the cannister assembly where desorption occurs.

In more detail, the exhaust manifold 70 is provided with an exterior hood 71 having lower skirts 72 which snuggly fit adjacent to the exhaust manifold, yet are open to incoming air. A central register 73 is also provided with a nozzle 74. Nozzle 74 in turn is attached by flexible conduit 75 connected at a port 76 say at the air intake line 16a of the air intake system of the embodiment of FIG. 2. At the air intake line 16a, a solenoid operator 77 is positioned so that it is damper 78 is in register with port 76. Opening the damper 78 allows warmed engine air to enter the cannister assembly (not shown).

SEQUENCE OF OPERATIONS Reference should now be had to the Figures illustrating the method aspects of the present invention. In more detail, it should be apparent that the initiation of the cold start cycle automatically occurs when the driver closes ignition switch 26c of the controller circuit 26 of FIGS. 1 and 5. Before the driver engages the ignition switch 260, however, the valve and conduit network 25 and particularly the evaporative control valve 250 is in the position illustrated in FIG. 10 to carry out the vapor adsorption control function of the present invention. That is to say, the evaporative 3-way control valve 250 is in a relaxed state so that its exhaust port 80 and inlet ports 81 and 82 are in fluid communication with fuel well 19 of the carburetor l3, and to the gas tank 23, respectively, say via

conduits

83 and 84. When the engine'is in an inactive state, and evapora tion of the fuel occurs, the vapors pass through

conduits

83 and 84, 3-way control valve 250 and conduit 38 to the vapor adsorption zone of the cannister assembly 27 of FIGS. 2 and 5. Adsorption of the vapor prevents its escape into the atmosphere.

Prior to initiation of cold start, assume the fuel well 19 has been emptied of full-range fuel. In this regard, consider also the function of drain conduit 85 of FIGS. 1 and 5 connected between fuel well 19 and gas tank 23. When the engine is in an inactive state, fuel within the fuel well 19 (liquid phase) drains therefrom via conduit 85 to the gas tank 23. As shown, the conduit 85 is provided with an oriface 86 so as to control the rate of drainage of the fuel, say at a rate which will allow total removal of all fuel from the well within a 6-12 hour period. Thus, when the engine is parked overnight, the drain conduit 85 in cooperation with oriface 86 provide for total removal of full range fuel from the fuel well 19. It should also be apparent that if the drainage conduit 85 is mounted at the side-wall of the fuel well (not at the bottom wall as shown) not all of the full range fuel will be drained. Instead, a residual reservoir remains, the amount of which is a function of the connector position relative to the top wall of the fuel well, e.g., if the connector to the fuel well and conduit is at a location say about, two-thirds of the way away from the top wall, the residual fuel would be onethird of the total fuel well capacity. During initial starting of the engine, the position of nozzle of the carburetor 13 could be arranged, depthwise, so that a selected, compatible mixture of the residual and eluted fuel would enter the carburetor to effect cold start of the engine.

Furthermore, it should also be apparent that the positions of the drain conduit 85 and fuel well 19 can be arranged such that the cold start fuel contribution provided by fuel well 19 can be essentially eliminated. Under such circumstances, the cannister assembly 27 is modified so that only rear section 27b is operative. That is, forward section 27a is eliminated from the cold start operation. Instead, the full-range fuel previously passing thereto is instead conveyed directly to the fuel well 19. But the positions of the nozzle 20 and fuel well 19 are arranged during the normal starting period such that little, of any, full-range fuel flows from the fuel well .19 via nozzle 20 into the carburetor 13.

As the engine turns over, the fuel pump 24 conveys full-range fuel through inlet start valve 25a to the cannister assembly 27 of FIGS. 2 or 5. Within the cannister assembly 27, the full-range fuel percolates simultaneously through the first and second elution zones culminating in the elution of low molecular weight components at fuel well 19 and at air intake assembly 12, respectively. High molecular weight components of the full-range fuel remain absorbed. A metered amount of the light components is conveyed through the carburetor 13 into the intake manifold 11 and thence to the combustion chambers of the engine. After selected rise in the engine temperature, as measured by bimetal switch 26b of the controller circuit 26 say positioned at the water jacket or exhaust manifold of the engine, control relay 26a becomes deactivated, resulting in the cold start inlet and exhaust valves 25a and 25b returning to relaxed positions as shown in FIG. 9. The fuel system thus switches over to full-range fuel, such fuel passing from fuel pump 24 via conduit 87a to inlet valve 25a and thence from U-shaped conduit 87b and exhaust valve 25b to the fuel well 19. As full-range fuel is utilized, the elution zones of the forward section of the cannister assembly followed by the rear section are placed in fluid contact with the carburetor.

It should be pointed out that during the operation of the engine, the evaporative control valve 25c of the valve and conduit network 25 remains an activated state as depicted in FIGS. 1, 5, and 9. However, when the driver opens the ignition switch 26c of the controller circuit 26, the evaporative control valve 250 is likewise deactivated which places it in the position depicted in FIG. 10 whereby the vapor adsorption zone of the forward section 27a of the cannister assembly 27 is in direct fluid contact with the fuel well 19 and gasoline tank 23. In that way, as evaporative emissions are formed within the fuel well 19 or the gasoline tank 23, they are conveyed via

conduits

83 and 84 respectively through inlet ports 81 ands 2, exhaust port and con duit 38 to the vapor adsorption zone.

While certain preferred embodiments of the invention have been specifically disclosed above, it should be understood that the invention is not limited thereto as many variations will be readily apparent to those skilled in the art and thus the invention is to be given the broadest possible interpretation within the terms of the following claims.

We claim: a

1. In a spark-ignition internal combustion engine of the type having an air intake system, a fuel intake system, and a carburetor means interconnected therebetween for mixing of full-range fuel with air to form a combustible mixture for delivery to combustion chambers of said engine, the improvement for reducing exhaust pollutants of said engine by dynamically varying the composition of said full-range fuel during cold starting of said engine (cold start cycle), comprising;

i. two-stage cannister means selectively connectable between said carburetor and a reservoir of said fullrange fuel and including separate first and second adsorption beds of adsorbent material each in flow arrangement with said reservoir means whereby said full-range fuel dynamically percolates thereover during said cold starting of said engine to elute first and second cold start fuel streams,

ii. said first stream being an atomized spray composed essentially of low molecular weight constitucuts and being carried into said carburetor by intake air of said air intake system,

iii. said second stream being composed essentially of low molecular weight liquid constituents and being conveyed under pressure to a fuel well of said carburetor, said first and second streams being mixed together along with air by said carburetor to form a highly combustiblecold start mixture for delivery to said combustion chambers of said engine,

iv. control means including flow condition means for controlling flow of said fuel including said cold start fuel streams between said reservoir means, said cannister means and said carburetor as a function of at least one of several engine operating parameters to assure at least substantially simultaneous delivery of said cold start fuel streams to said carburetor during cold starting of said engine.

2. The improvement of claim 1 in which said flow condition means of said control means is further characterized by a first active state initiated by occurrence ofa selected engine parameter indicative of the start of said cold start cycle whereby said full-range fuel is allowed to flow in parallel from said reservoir means to each of said adsorbent beds in said cannister means to initiate elution of said first and second cold start fuel streams and whereby said first and second cold start fuel streams are allowed to flow in parallel from said cannister means to said carburetor to form said highly combustible cold start fuel-air mixture.

3. The improvement of claim 2 in which said absorbent materials comprising said first and second adsorbent beds are selected on a basis of providing efficient retardation of high molecular weight constituents of said full-range fuel percolating therethrough so that essentially only low molecular weight constituents are eluted from each of said beds of said cannister means during cold starting of said engine.

4. The improvement of claim 3 in which said adsorbent material is selected from the group consisting of silica gel, alumina, barium sulfate, calcium carbonate, glass, resins and plastics, quartz, titanium dioxide, metallic oxides and zeolites, adapted for use in liquidliquid partition chromatography.

5. Apparatus for reducing exhaust and inoperative pollutants produced by a spark-ignition internal combustion engine of the type including an air intake system, fuel intake system, and a carburetor intercon nected therebetween for mixing full-range fuel with air to form a combustible mixture for delivery to combustion chambers of said engine, comprising:

i. a two-stage cannister assembly including first and second sections each containing a bed of adsorbent material capable of selectively eluting at cold start first and second parallel cold start fuel streams each composed essentially of only low molecular weight constituents, said first stream being composed of low molecular weight liquid constituents conveyed to a fuel well of said carburetor said second stream being an atomized spray carried into said carburetor by intake air of said air intake systems, said first and second streams being mixed together with air by said carburetor, said first section also including another bed of adsorbent material capable of selectively absorbing vapor constituents of said full-range fuel during an inoperative state of said engine,

ii. valve and conduit network means attached between said cannister assembly, a reservoir means for said full-range fuel and said carburetor for providing selective flow of said fuel including said cold start fuel between said cannister assembly, said reservoir means and said carburetor, said network means including a first plurality of conduit and valve means including first and second valve means controlling parallel flow relative to each of said sections of said cannister assembly so as to allow, (a) in a first operating state flow of said full-range fuel from said reservoir means to said each section and flow of said first cold start fuel stream from said cannister assembly to said carburetor to provide for rapid starting of said engine without producing excessive exhaust pollutants and (b) in a second operating state, full-range fuel to flow from said reservoir means to said carburetor bypassing said cannister assembly after said engine is in a normal running condition, said network means also including a second plurality of conduit means including a third valve means operatively connected between said another bed of said first section of said cannister assembly said fuel reservoir means and said carburetor for selectively conveying vapor emissions of said fuel within said fuel reservoir and- /or said carburetor to said another bed when said engine is in said inoperative state,

iii. control means operatively connected to said first, second and third valve means of said valve and conduit network for changing operation states so as to direct fuel flow relative to said cannister assembly, said reservoir and carburetor as a function of one or more engine operating parameters.

6. Apparatus of claim 5 in which said carburetor includes a fuel well and a bore each in selective contact with said first and second sections of said cannister as.- sembly and said reservoir means through said first plurality of conduit means including said first and second valve means, said first valve meansbeing positioned between said reservoir means and a parallel inlet of each of said sections of said cannister assembly and having first and second operating states for controlling flow of full-range fuel between said reservoir means relative to each of said section and said second valve means, said second valve means being positioned between said fuel well and an outlet of said first section and also having first and second operating states coextensive in time with said operating state of said first valve means for controlling flow of said full-range fuel and said cold start fuel stream from said first sections relative to said fuel well as a function of engine temperature.

7. The apparatus of claim 6 in which said fuel well and said reservoir means are placed in selective vapor contact with said another bed of said first section through said second plurality of conduit means including said third valve means as a function of a selective engine parameter indicative of said inoperative state in said engine whereby evaporative vapor emissions from said full-range fuel within said fuel well and said reservoir means can be conveyed to said another bed of said first section for adsorption therein thereby preventing escape into atmosphere surrounding said engine.

8. Apparatus of claim 7 in which said first and second adsorbent beds are formed of a polar adsorbent material while said another adsorbent bed is formed of a nonpolar adsorbent material.

9. Apparatus of claim 6 in which said first section includes an elongated tubular means disposed within a forward section of a shell housing while said second section is disposed within a rear section of said shell housing with air intake control means connected to a source of heated gas, so as to allow selective flow of said heated gas through said first and second sections for purging both said first, second and another bed of adsorbed fuel constituents, said purged constituents being carried into and consumed within said combustion chambers of said engine.

' 10. Apparatus of claim 9 in which said air intake system includes an air cleaner assembly having an air intake line and an air filter, said air intake line including.

support means for rigidly supporting said cannister assembly in flow relationship with a bore of said carbure-

Claims

1. In a spark-ignition internal combustion engine of the type having an air intake system, a fuel intake system, and a carburetor means interconnected therebetween for mixing of fullrange fuel with air to form a combustible mixture for delivery to combustion chambers of said engine, the improvement for reducing exhaust pollutants of said engine by dynamically varying the composition of said full-range fuel during cold starting of said engine (cold start cycle), comprising; i. two-stage cannister means selectively connectable between said carburetor and a reservoir of said full-range fuel and including separate first and second adsorption beds of adsorbent material each in flow arrangement with said reservoir means whereby said full-range fuel dynamically percolates thereover during said cold starting of said engine to elute first and second cold start fuel streams, ii. said first stream being an atomized spray composed essentially of low molecular weight constituents and being carried into said carburetor by intake air of said air intake system, iii. said second stream being composed essentially of low molecular weight liquid constituents and being conveyed under pressure to a fuel well of said carburetor, said first and second streams being mixed together along with air by said carburetor to form a highly combustible cold start mixture for delivery to said combustion chambers of said engine, iv. control means including flow condition means for controlling flow of said fuel including said cold start fuel streams between said reservoir means, said cannister means and said carburetor as a function of at least one of several engine operating parameters to assure at least substantially simultaneous delivery of said cold start fuel streams to said carburetor during cold starting of said engine.

2. The improvement of claim 1 in which said flow condition means of said control means is further characterized by a first active state initiated by occurrence of a selected engine parameter indicative of the start of said cold start cycle whereby said full-range fuel is allowed to flow in parallel from said reservoir means to each of said adsorbent beds in said cannister means to initiate elution of said first and second cold start fuel streams and whereby said first and second cold start fuel streams are allowed to flow in parallel from said cannister means to said carburetor to form said highly combustible cold start fuel-air mixture.

4. The improvement of claim 3 in which said adsorbent material is selected from the group consisting of silica gel, alumina, barium sulfate, calcium carbonate, glass, resins and plastics, quartz, titanium dioxide, metallic oxides and zeolites, adapted for use in liquid-liquid partition chromatography.

5. Apparatus for reducing exhaust and inoperative pollutants produced by a spark-ignition internal combustion engine of the type including an air intake system, fuel intake system, and a carburetor interconnected therebetween for mixing full-range fuel with air to form a combustible mixture for delivery to combustion chambers of said engine, comprising: i. a two-stage cannister assembly including first and second sections each containing a bed of adsorbent material capable of selectively eluting at cold start first and second parallel cold start fuel streams each composed essentially of only low molecular weight constituents, said first stream being composed of low molecular weight liquid constituents conveyed to a fuel well of said carburetor said second stream being an atomized spray carried into said carburetor by intake air of said air intake systems, said first and second streams being mixed together with air by said carburetor, said first section also including another bed of adsorbent material capable of selectively absorbing vapor constituents of said full-range fuel during an inoperative state of said engine, ii. valve and conduit network means attached between said cannister assembly, a reservoir means for said full-range fuel and said carburetor for providing selective flow of said fuel including said cold start fuel between said cannister assembly, said reservoir means and said carburetor, said network means including a first plurality of conduit and valve means including first and second valve means controlling parallel flow relative to each of said sections of said cannister assembly so as to allow, (a) in a first operating state flow of said full-range fuel from said reservoir means to said each section and flow of said first cold start fuel stream from said cannister assembly to said carburetor to provide for rapid starting of said engine without producing excessive exhaust pollutants and (b) in a second operating state, full-range fuel to flow from said reservoir means to said carburetor bypassing said cannister assembly after said engine is in a normal running condition, said network means also including a second plurality of conduit means including a third valve means operatively connected between said another bed of said first section of said cannister assembly said fuel reservoir means and said carburetor for selectively conveying vapor emissions of said fuel within said fuel reservoir and/or said carburetor to said another bed when said engine is in said inoperative state, iii. control means operatively connected to said first, second and third valve means of said valve and conduit network for changing operation states so as to direct fuel flow relative to said cannister assembly, said reservoir and carburetor as a function of one or more engine operating parameters.

6. Apparatus of claim 5 in which said carburetor includes a fuel well and a bore each in selective contact with said first and second sections of said cannister assembly and said reservoir means through said first plurality of conduit means including said first and second valve means, said first valve means being positioned between said reservoir means and a parallel inlet of each of said sections of said cannister assembly and having first and second operating states for controlling flow of full-range fuel between said reservoir means relative to each of said section and said second valve means, said second valve means being positioned between said fuel well and an outlet of said first section and also having first and second operating states coextensive in time with said operating state of said first valve means for controlling flow of said full-range fuel and said cold start fuel stream from said first sections relative to said fuel well as a function of engine temperature.

10. Apparatus of claim 9 in which said air intake system includes an air cleaner assembly having an air intake line and an air filter, said air intake line including support means for rigidly supporting said cannister assembly in flow relationship with a bore of said carburetor.