US3838667A

US3838667A - Fuel injection cold start and evaporative control method and apparatus for carrying out same

Info

Publication number: US3838667A
Application number: US00295040A
Authority: US
Inventors: S Csicsery
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 initied in a spark-ignition internal combustion, fuel injection engine, lower molecular weight constituents of a full-range gasoline are selectively eluted by an elution system including an adsorbent bed of adsorbent material, for example, silica gel. The adsorbent bed forms an elution zone within a cannister assembly in fluid contact with the full-range gasoline. The adsorbent material-usually in pelletized form-is preferably housed within a tubular means being positioned within a much larger shell housing in fluid contact with a valve and conduit network. Entry of the gasoline is initiated by the valve and conduit network under control of a fuel injection control circuit. 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 gasoline tank.

Description

United States Patent Csicsery FUEL INJECTION COLD START AND EVAPORATIVE CONTROL METHOD AND APPARATUS FOR CARRYING OUT SAME [75] Inventor: Sigmund M. Csicsery, Lafaeytte, Calif.

[73] Assignee: Chevron Research Company, San

Francisco, Calif.

[22] Filed: Oct.'4, 1972 [21] Appl. No.: 295,040

[52] US. Cl 123/3, 123/127, 123/180 R,

123/180 A [51] Int. Cl. F02m 27/02 [58] Field of Search 123/32 EA, 179 L, 180 R, 123/180 A, 127, 3, 133, 135

[56] References Cited UNITED STATES PATENTS 1,490,192 4/1924 Anderson 123/127 3,221,724 12/1965 Wentworth 123/136 3,494,340 2/1970 Weber et al 123/139 AW X 3,635,200 l/l972 Rundell et al. 123/3 3,673,989 7/1972 Aono et al 123/32 EA 3,688,755 9/1972 G'rayson et al 123/3 Primary Examiner-Charles J. Myhre Assistant Examiner--William Rutledge, Jr. Attorney, Agent, or FirmR. L. Freeland, Jr.; H. D. Messner ABSTRACT As cold start is initied in a spark-ignition internal combustion, fuel injection engine, lower molecular weight constituents of a full-range gasoline are selectively eluted by an elution system including an adsorbent bed of adsorbent material, for example, silica gel. The adsorbent bed forms an elution zone within a cannister assembly in fluid contact with the full-range gasoline. The adsorbent material-usually in pelletized form-is preferably housed within a tubular means being positioned within a much larger shell housing in fluid contact with a valve and conduit network. Entry of the gasoline is initiated by the valve and conduit network under control of a fuel injection control circuit. 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 gasoline tank.

8 Claims, 9 Drawing Figures VAPOR CONTROL. VALVE RELAY FUEL INJECT CONTROL CIRCUIT was.

srmaur PAIEMEUBU 11914 FUEL INJECTION COLD START AND EVAPORATIVE CONTROL METHOD AND APPARATUS FOR CARRYING OUT SAME RELATED APPLICATIONS Applications filed simultaneously with the subject disclosure which are assigned to a common assignee and containing common subject matter but claiming distinct inventions, include:

Single-stage Cold Start and Evaporative Control Method and Apparatus for Carrying Out Same, Sigmund M. Csicsery, Ser. No. 295,028; Two-Stage Cold Start and Evaporative Control System and Apparatus for Carrying Out Same, Sigmund M. Csicsery and Bernard F. Mulaskey, Ser. No. 295,029; Cold Start Method and Apparatus for Carrying Out Same, John F. Senger, Ser. No. 295,041; Two-Stage Fuel-Injection Cold Start Method and Apparatus for Carrying Out Same, Sigmund M. Csicsery and Bernard F. Mulaskey Ser. No. 295,030, now abandoned.

The present invention relates to cold starting and evaporative emission control of a spark-ignition, fuel injection internal combustion engine and has for an object of 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 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, fuel injection internal combustion engines, the fuel-air ratio is generated by the air-fuel intake system, say a conventional fuel injection 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 pluality of interrelated well-known parts, the lower molecular weight constituents become more easily vaporized to form combustible vapor-fuel/ air ratios to allow starting of the engine even at low operating temperatures. However, since remaining higher molecular weight constitutents 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 more 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 snark-ignition, fuel injection internal combustion engine (particularly during cold start), lower molecular weight constituents of a full-range gasoline are selectively eluted as cold start is initiated by the driver. The elution system includes an adsorbent bed of adsorbent material, preferably of the polar type,

for example, silica gel forming an elution zone within a cannister assembly in fluid contact with the full range gasoline. The adsorbent material-usually in pelletized form-is preferably housed within a tubularmeans disposed within the cannister assembly, the tubular means being positioned within a much larger shell housing in fluid contact with a valve and conduit network. Entry of the gasoline is initiated by the valve and conduit network under control of a fuel injection control circuit.

Construction of the cannister assembly can vary. Preferably the arrangement resembles that provided for a shell-and-tube heat exchanger whereby tube-side gasoline-during cold startpasses through the tubular means packed with the adsorbent material (single pass percolation). Selective retardation of the higher molecular weight compounds vis-a-vis the lower components occurs so that, during start up, only the latter constituents pass to each of a series of electromagnetic injectors in a preselected time sequence, and thence are mixed with air in a preselected air-fuel ratio 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 one to two orders longer, say from I to 3 minutes, the latter compounds remain selectively adsorbed with the elution zone.

Preferably, but not necessarily, the present invention has additional utility in preventing evaporative emissions originating 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 fuel injection engine in an inoperative state, is acknowledged as being a serious environmental problem, especially within large cities. 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 from gas tanks: 6 grams per day under standard operating conditions. In this regard, the present invention can be selectively, but not necessarily, operative during such time periods to adsorb such evaporative emissions and prevent their escape into the atmosphere by arranging the cannister assembly so as to provide an annular space between the tubular means and the shell housing. Into the annular space can be inserted an adsorbent material, 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 fuel injection control 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 adsorbed 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 lower 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.

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 FIG. 1 is a schematic view of a portion of an engine fuel system incorporating the present invention illustrating a typical fuel injection system and air cleaner assembly 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 network controlled by a fuel injection control circuit;

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

FIG. 3 is a sectional view taken along line 33 of the cannister assembly of FIG. 2;

FIG. 4 is a schematic view of another embodiment of the present invention illustrating, in association with a typical fuel injection system and air cleaner assembly, a cannister assembly mounted by means of a platform attached to the firewall of the engine compartment;

FIG. 5 is a plan view of the cannister assembly and air cleaner assembly of FIG. 4;

FIG. 6 is a circuit diagram of the fuel injection control circuit of FIG. 1 illustrating how the injection cycle and cold start cycle are interrelated;

FIG. 7 is a partially schematic view illustrating an alternative embodiment by which air can be heated in an elevated temperature to better desorb the cannister assembly of FIGS. 1 and 4;

FIG. 8 is a fragmentary view of the valve and conduit network of FIG. 1 illustrating the position of the valve network after cold start has been achieved and the engine is at running temperature so that the cannister assembly can be desorbed;

FIG. 9 is yet another fragmentary view of the valve and conduit network when the engine is in an inoperative state.

Referring now to FIG. 1, there is illustrated a combustion chamber 9 of a spark-ignition internal combustion engine connected to an engine fuel system 10 through an engine intake manifold 11. Fuel system 10 of the present invention includes an air intake assembly 13, a fuel intake system 14 and a fuel injection control circuit 15.

To form a combustible air-fuel mixture, air enters by way of air intake assembly 13 say by way of air inlet line 13a, and is filtered at an air filter interior of an air filter housing 130, before entry into intake manifold 11. Manifold ll includes air temperature gauge 16, butterfly valve 17, vacuum sensor 18, and a mixing chamber 19 connected to combustion chamber 9 through intake valve 12. Also connected to the mixing chamber 19 adjacent to intake valve 12 is a fuel injection valve 20. Fuel injector valve 20 allows a metered quantity of gasoline to be mixed with air passing into mixing chamber 19 so as to provide a resulting fuel-air mixture passing through intake valve 12 into the combustion chamber 9 where combustion occurs. A segment of fuel intake system 14 includes a gas tank 21 containing a reservoir of full-range fuel (i.e. a full-boiling gasoline), a filter 22, a pump 23 anda pressure regulator 24. Pump 23 is driven through a motor 25 connected to fuel injector control circuit 15 to pump fuel by way of cold start inlet valve 26a of conduit and valve network 26 and thence to a cannister assembly 28, mounted adjacent to the air intake assembly 13 say within air inlet line 13a.

Valve and conduit network 26 is seen to also include a cold start exit valve 26b, controlled mechanically by cold start relay means 30 through transducer 31. A second relay means 32 is seen to control operation of evaporative emissions control valve 26c of valve and conduit network 26 through mechanical transducer 33.

Transducers

31 and 33 convert rectilinear-travel of the relay means 30 and 32 to rotational motion. However, note that instead of being regulated by control circuit 15, the second relay means 32 is seen to be controlled by ignitionswitch 35 connected to battery 34. Thus, the activity of ignition switch 35 is directly reflected in operation of theevaporation control valve 26c connected to the relay means 32, in the manner explained in more detail below.

Fuel injection control circuit 15 is also seen to be connectable to battery 34 as ignition switch 35 is closed, the battery 34 being itself connected to a generator (not shown) in conventional manner, say by way of a regulator. When ignition switch 35 is closed, the control circuit 15 becomes operational. Input information by way of the following transducers is received: air temperature gauge 16, vacuum sensor 18, engine temperature indicator 36, travel sensor 37, RPM and shaft angle indicator 38. From this data the circuit 15 commands relevant parts of the fuel system 10 using a selected binary code of current pulses (ONE-ZERO), to adapt fuel requirements at the injector 20 to changing conditions of operations. E. g., in this regard, the period time of, say the ONE state can be used to indicated the energization period of each of a series of injectors 20, while the ZERO state to indicate the inactivity period of relevant elements of the system.

In more detail, the start of each pulse at a particular injector, say injector number 2 (of 8) is synchronized (timed) to occur when a particular shaft angle indication is provided by shaft angle-RPM indicator 38. After a pulse has been correctly initiated, its period (pulse width) is basically a function of the manifold pressure (engine load) asprovided by vacuum sensor 18. Corrections by which pulse width is stretched or diminished, are a function of data supplied by the remaining sensors, i.e., air intake temperature, engine temperature throttle valve movement and engine speed.

Prior art electronic fuel injection systems have had difficulty in providing fuel requirement at cold start even when using a separate start valve attached to intake manifold. The present invention provides a cold start function through selective elution of a fuel range gasoline, percolating through cannister assembly 28 for providing light, low molecular weight liquid components at the injector valves 20 for mixing with air to form the cold start fuel-air mixture. A cold engine is one which, in attempting to assume an ambient air'temperature, has cooled to a temperature below a selected level. This level is empirically determined and is the temperature below which difficulty of starting isincreased beyond the usual capability of fuel injection control circuit 15.

In accordance with the present invention, lower temperature limits for starting of an internal combustion engine, are extended using only light, low molecular weight liquid components of a full-range fuel, i.e., a full-boiling gasoline, at startup. Note that although a full-range fuel is conveyed from gas tank 21 through pump 23 into valve and conduit network 26, and thence to cannister assembly 28 only lightweight constituents are eluted from cannister assembly 28 and carried to the injector valves 20 for mixing with air. The principal reason for such operation: selective retardation of heavier components has occurred during the initial 1-to-3 minutes of the starting cycle of the internal combustion engine due to the operational characteristics of the cannister assembly 28. Since the nature of the assembly 28 is based on functional characteristics of adsorbent materials, in general, and of polar type adsorbent materials, in particular, a brief discussion of adsorption systems is believed to be in order and is presented below with reference to FIG. 2.

Cannister assembly 28 includes an interior tubular means 41, located within a much larger shell housing 42. In essence, the tubular means 41 forms a column of a solution adsorption, frontal analysis chromatograph 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, full-boiling gasoline enters by way of inlet conduit 43 and percolates through adsorbent material 44 packed within the tubular means 41. Note at the outlet conduit 46, 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 heavier molecular weight constituents within the tubular means 41 shuffle at a slower rate between the mobile and stationary phases than do the lighter constituents. Thus, within elution zone 40, coextensive with but interior of tubular means 41, separation is believed to occur, inter alia, because of polarity, nonpolarity characteristics of the constituents whereby different relative velocities are imparted to the individual molecules of the groupings. The least strongly adsorbed low molecular weight components elute as a group at the outlet conduit 46 first, followed by a second grouping containing say both light and heavy constituents and so forth until all constituents have appeared.

Residence time of the light components within the elution zone 40 is a function of many factors including the length of the tubular conduit means 41 as well as the pressure drop during percolation through the adsorbent material 44. However, the residence time of the heavier components is much longer in duration, in a range of 1-3 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 due to relative polarnonpolar interaction between the heavier components versus the adsorptive material 44, is quite long, say 1-3 minutes, while the typical starting cycle of a modern engine can be quite short, say from 1 second up to seconds (except when problems of starting occurs), the heavier constituents remain adsorbed within the tubular means 41 after the engine has started. This proposition assumes, of course, that the adsorbent material 44 constituting the elution zone 40 is of a compatible polar classification.

As previously mentioned, competition for the heavier molecular weight groupings of the full-range fuel is believed to be dependent, more or less, on its selective polar interaction with the adsorptive material 44. The magnitude of interaction (between the material 44 and the heavier constituents of the full-range fuel) is believed to be directly related to the degree of polarity of the adsorptive material. In accordance with the present invention, then, adsorptive material 44 is preferably polar, and preferably selected from the following nonexclusive listing of popular polar adsorptive materials, with silica gel being somewhat preferred.

Polar Adsorptive Materials Remarks Ion-exchange only Commonly Used in Liquid-liquid Partition Chromatography Adsorbent material 44 can be formulated in a convenient form for use within the cannister assembly 28. For example, the elution zone 40 can be formed of adsorbent material in granular, pelletized 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 tubular means 41, say pelletized lines set forth in Kirk- Othmer, op. cit., Volume 1, page 460. Since, as previously mentioned, the flow rate of the full range gasoline within the elution zone 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 44 should be such as to minimize the pressure drop across a cannister assembly 28 without adversely affecting its ability to adsorb the heavier constituents. In this regard, an elution zone 40 having about a 1-liter capacity filled with activated alumina of 8 by 14 mesh has been found to adsorb from 200-300 ml. of aromatic constituents while yielding about 400 to 500 ml. of lightweight constituents in the first initial minutes of the cold starting operation. In addition to activated alumina, it has been found that polar gels, such as silica gel, titania gel, zirconia gel, and alumina gel, as well as Fullers earth, bentonite, diatomaceous earth, forisil, attuplugus, and any other polar adsorptive materials are also useful in carrying out the present invention. However, in some cases, non-polar materials may also be used within the elution zone as a substitue for the above-identified polar materials without undue loss in effectiveness. Non-polar materials listed hereinafter are appropriate in this regard.

Construction of the cannister assembly 29 varies with the type of mounting required to attach the conduit and valve network 26 adjacent to air intake system 13. In FIG. 2, cannister assembly 28 is seen to be mounted within the intake air line 13a of the air intake system 13. The overall diameter of the cannister assembly 28 thus must be minimum so as to allow sufficient air to bypass through intake manifold 11 to mixing chamber 19. To accomodate the required volume of adsorbent material constituting the elution zone 40 the tubular means 41 may have to be correspondingly ultra-long. Support of the ultra-long tubular means 41 can be brought about by welding radial supports 47 to the side wall of air line 13a to which

cold start conduits

43, 46, as well as evaporative conduit 60 are attached. Support rings 51 are attached at respective ends of the tubular means 41. Each ring 51 has a peripheral edge .in contact with the shell housing 42. Each ring 51 also in eludes a central plug zone in plugging contact with the central tubular means 41 as well as an intermediate zone 53 (See FIG. 3) including a series of ports 54 in registry with an annular spacing existing between tubular means 41 and the shell housing '42 wherein adsorbent material 55 is supported. Adsorbent material 55 .located in the aforementioned annular space constitutes a vapor adsorption zone, generally indicated at 56 (adsorption capture zone). In this aspect of the invention, deactivation of ignition switch 35 (of FIG. 1) deactivates relay means 32 causing rotation of the vapor control valve 260 to the position shown in detail in FIG. 9. The gas tank 21 is thus placed in fluid contact with the vapor adsorption zone 56. Note that at the shell side exterior of the central tubular means 41, i.e., within adsorption zone 56, the atmosphere is permitted to enter and leave at will. During cold start, since the shell-side air is at about the same temperature as the fluid interior of the tubular means 41, little heat is transferred between the two fluids.

In FIG. 4, the support of the cannister assembly 28 differs markedly from that of FIG. 1. The cannister assembly 28 of FIG. 4 is seen to be mounted by shell housing 42 to a platform 57 which in turn is attached to a firewall (not shown) of an engine compartment. Additional space afforded by the platform 57 allows for a more complex constructional design of the cannister assembly 28. Instead of constructing tubular means 41 ofa single tube as depicted in FIG. 1, a series of upright tubular means 41 can'be provided to carry the gasoline entering inlet chamber 59 along a series of sinusoidal passages through the interior of the cannister assembly 28, such passageways-resembling those provided in a conventional tube-and-shell heat exchanger. The series of passes made by the gasoline are indicated by solid arrows 60, while clotted arrows 61 indicate the directions of the gas phase flow.

In the depicted arrangement, tube-side gasoline is conveyed during cold starting through the tubular members 41' between the inlet and

exhaust chambers

59 and 62 respectively (multipass percolation) through adsorbent material 44' packed within the tubular members 41. Due to increased total length of the tubular means 41, the resulting, composite elution zone 40' is likewise greatly enlarged over that depicted in FIG. 2, assuming the absolute length of the cannister assembly of FIG. 4 remains the same. Not only does the effluent at the exhaust chamber 62 consist essentially of light, low molecular weight constituents during the cold start cycle, as previously explained, but also the heavier compounds remain adsorbed within adsorbent material 44- until long after the engine has warmed up. That is to say, because the heavier compounds are retarded during percolation through the elution zone 40 for a longer time than required to usually start the engine, the effluent within the intake manifold per each starting cycle of the internal combustion engine is limited essentially to lightweight constituents.

Further constructural differences between the embodiments depicted in FIG. 1 and FIGS. 4 and 5 are readily apparent. For example, in FIG. 5, the shell housing 42' is seen to be rectangular in cross-section whereby the assembly forms a parallelpipedon. Also, the housing 42' is also seen to include end walls 63. Each end wall 63 includes a series of ports 64 to allow selective entry (in direction of arrows 61) of hot, exhaust gases into an adsorptive vapor capture zone generally indicated at 56 exterior of tubular members means 41', but interior of shell housing 42'. Within the vapor capture zone 56', adsorbent material 55' is supported. One of the end wall 63 is also seen to attach by way of fasteners to the air cleaner housing 130. Such attachment is oriented such that its ports 64 are in registry with aperature 13b of the air cleaner housing 13c. The other of the end, the end wall 63 is seen to be connected to a conduit 65 having a remote end (not shown) connected to a source of exhaust gases, say the exhaust manifold of the engine.

Of course, tubular member means 41' need not be discontinuous so as to require the use of intermediate chamber 66 (FIG. 4) to reverse the flow of the mobile phase. E.g., the tubular member means 41' can be U- shaped with remote ends in fluid contact with inlet and exhaust chambers 58, 62 respectively.

The operation of fuel injection control circuit 15 during cold start as well as under normal driving conditions will now be described. As previously mentioned, control injection control circuit 15 of FIG. 1 receives various sensory inputs indicative of various engine operating parameters after the circuit has been initialized. Of primary importance at cold start, is a signal indication of engine temperature, such signal appearing at terminal 70 of the injection control circuit 15 of FIG. 6. Assume such signal at terminal 70 is below a selected set point level, so that relay means 30 (FIG. 1) is activated as the driver closes ignition switch 35. The inlet and exhaust cold start valves 26a and 261;, as well as evaporative control valve 26c, are reoriented from the positions shown in FIG. 9 to those positions shown in FIG. 1. As the engine turns over, the pump 23 conveys full-range fuel through inlet start valve 26a to the cannister assembly 28. Within the cannister assembly 28, the fullrange fuel percolates through the elution zone culminating in the elution of low molecular weight components at each of a series of injector valve 20. Heavier components of the full-range fuel remainadsorbed. From the injector valve 20, a metered amount of the lightweight components is conveyed into the mixing chamber 19 where the fuel and air are properly mixed and then convey for consumption within the combustion chambers of the engine. After selected rise in the engine temperature, as indicated at terminal 70 of FIG. 6 relay means 30 becomes deactivated, resulting in the cold start inlet and exhaust valves 26a and 26b returning to relaxed positions as shown in FIG. 8.

After cold start exhaust and inlet valves 26a and 26b return to relaxed positions depicted in FIG. 8, the fuel intake system switches over to full utilization of the full-range gasoline. That is to say, fuel conveyed from pump 23 of FIG. 1 passes to inlet cold start valve 26a via conduit 67a and thence from the valve 26a through U-shaped conduit 67b and exhaust cold start valve 26b into the ejector valve 20 as a function of control signals provided in fuel injection control circuit 15.

FIG. 6 illustrates the operation of fuel injection control circuit in detail. As indicated, the control circuit 15 is energized by a voltage supply designated as B+, as noted. In the application of this system to an automobile, the voltage supply B+ can be a battery and/or a battery charging system and additionally can provide a polarity readily reversed from that illustrated.

As explained previously, the control circuit 15 through designated circuit elements receives the following sensory inputs indicative of engine operating parameters.

rent source, and current is passed through thyristors 86 to coil 87 of one of a series of injector systems 69.

It should be apparent that at each injector coil 87, selection is controlled through coordination of angular postiion of the shaft of the engine as provided by transducer 38. In that way, synchronization of the time of appearances of the control pulses provided by the pulse generator at the individual terminal 711) with the time of energization of the multivibrator circuit 72.

After the transistor 85 conducts. transistor 80 is rapidly triggered into conduction as voltage at its base 80b (as determined by the adjacent RC network) decays to the value needed for the multivibrator circuit to relax. As a result, transistor 75 is biased off, but it is quickly returned to a conducting state as the transistor 80 is biased off. To return the transistor 75 to a conducting state, it should be apparent that as conduction of transistor 80 occurs it acts in cooperation with the voltage supply and

adjacent resistors

88 and 89 as a current source to provide a base current to transistor 75 and Signal Source Parameter Operational Circuitry (FIG. I (FIG Manifold pressure Engine temperature Parameters Acceleration Engine Speed Air Temperature Shaft Angle Speed circuit 97 Engine temperature circuit 95 Acceleration circuit 96 Air Temperature Circuit 98 In essence, the control circuit 15 generates a plurality of control pulses, the width of which is linearly variable with a fundamental parameter, namely, the manifold pressure of the engine, as well as being capable of being stretched or diminished by remaining engine parameters. In order to initiate operations, as the driver closes the ignition switch 35, a pulse generator (not shown) is energized. The pulse generator (not shown) is connected to the input terminal 71a of multivibrator cir cuit 72 via shaft angle transducer 38. In that way, the pulse generator is operative as a function of shaft angle so as to synchronize operation of the bistable multivibrator circuit 72 with angular position of the shaft of the engine. To provide similar synchronizing operations relative to particular injectorvalve 20, the pulse generator also provides (via transducer 38) a pulse signal at input terminal 71b of injection valve circuit 69.

As shown in detail in FIG. 6, multivibrator circuit 72 includes a coupling capacitor 73 in series with base 74 of transistor 75 via diode 76 and resistor 77. Shunting the coupling capacitor 73 is a second diode 78 (through which the capacitor 73 can be discharged) and a resistor 79.

A start pulse received at base 74 of transistor 75 from the pulse generator, will trigger the multivibrator circuit into its unstable state, i.e., transistor 75 into a conducting state. Mating transistor 80 of the multivibrator circuit is base connected to collector 75a of the transistor 75 through a

network comprising resistors

81 and 82 and capacitor 83. As transistor 75 conducts, the transistor 80 is caused to assume a voltage below its conduction state. However, voltage at collector 80a of the transistor 80 will rise toward the B+ value. and that value will be communicated via resistors 84a and 84b to power transistor 85. The power transistor 85 in conjunction with an adjacent resistor network acts as a curcauses the transistor to conduct. The rate of switching between the transistors 75 and is rapid enough that it does not affect operation of power transistor 85. Le, even though the multivibrator circuit is undergoing rapid switching of

transducer

75 and 80, the power transistor remains in a conducting state. However, the multivibrator circuit 72 can be made to relax to its stable state upon the receipt of a negative pulse at the base 74 of transistor 75, such negative pulse being generated by a separate control circuit 90.

Control circuit is seen to include variable resistor 91, condenser 92 and unijunction transistor 93 connected in parallel with base 74 of the transistor 75. When the voltage on the emitter of unitransistor 93 (provided via a RC

network comprising resistors

91 and 94 and condenser 92), is equal to the voltage at its base 930, the unitransistor 93 is energized causing a negative pulse to appear at base 74 of the transistor 75. The result: the multivibrator circuit 72 returns to a stable state. Voltage at the emitter of the unitransistor 93 is seen to be determined by the time constant of the aforementioned RC network, while the voltage appearing at base 93a is a function of composite voltage generated from the following control circuits, (i) engine temperature circuit 95, (ii) acceleration circuit 96, (iii) speed circuit 97 and (iv) air temperature circuit 98.

Engine temperature circuit operates to increase pulse width as a function of temperature, but the tem-' perature which causes circuit 95 to become operative must be below a selected point level, as explained below. Temperature circuit 95 is seen to include a voltage divider 99 formed by

resistors

100, 101 and transistor 102. Assume the transistor 102 isconducting, i.e.,

resistor network

103, 104 and 105 at its base, connect to the voltage supply B+ as shown. As the transistor 102 conducts, the change in voltage at the collector 102a is seen to be a direct indication of engine temperature.

In other words, the change in voltage of the collector 102a of the transistor 102 is reflected by the voltage divider 99 which in turn is reflected by a change in voltage at base 93a of unitransistor 93.

To provide a selected set point level for operation of the temperature circuit 95, the

resistors

103, 104 and 105 are chosen such that the transistor 102 saturates at a given engine temperature providing a balanced condition at voltage divider 99.

Air temperature circuit 98 operates in a similar manner as the engine temperature circuit 95. As indicated, a voltage divider 107 is formed by

resistors

108 and 109 and transistor 110. As previously, voltage at the base of the transistor 110 is controlled by

base resistors

111, 112 and 113 connected to the supply 13+. The air temperature is indicated by the internal resistance of the transistor 110 as reflected in change in collector voltage.

Acceleration circuit 96 is seen to include capacitor 114, resistor 115 and potentiometer 116 which operates in cooperation with a voltage divider 117 comprising

resistors

118, 119 and transistor 120. Arm 116a of the potentiometer 1 16 is seen to connect via transducer 1 16b to the butterfly valve of the engine via accelerator pedal 121. Thus movement of the pedal 121 causing displacement of the wiper arm 116:: changes the bias voltage appearing at base 120a of the transistor 120. Assume that the transistor 120 has been driven into conduction, but the voltage divider 117 formed therewith is unbalanced. Thus the change brought about by the movement of the arm 116a will cause a change in the collector voltage at collector 120b as a function of pedal movement. The operation of the acceleration circuit 96 occurs during a variable time period dependent upon the time constant of the

resistors

115, 125, the potentiometer 116 as well as capacitor 114.

Speed circuit 97 is for the purpose of correcting for a lag time of air flow into the engine. Aerodynamic effects lead to a decrease in the rate of air intake as a function of increasing engine speed. Circuit 97 includes a potentiometer 122 having an arm 122a connected by a transducer 122b to a tachometer (not shown) operative when a set point level is exceeded to change the voltage level at the base 93a of unitransistor 93 in the manner previously described.

Now returning to the embodiment depicted in FIG. 1 under control of the fuel injection control circuit of FIG. 6, it is apparent that controls are there shown which will allow usage of full or partial engine air warmed to a high temperature for desorption purposes. It should also be noted that the embodiment of FIG. 4 contemplates utilization of gases from the exhaust manifold to purge with the elution and vapor adsorption zones of adsorbed constituents. Now in more detail, after the engine has started and warmed, and utilization of the full range fuel via reorientation of cold start valves 26a and 26b to the positions shown in FIG. 8, is occurring, simultaneously therewith, the elution zone of the cannister assembly 28, as well as the vapor zone of gas tank 21, are placed in fluid contact with the intake manifold 11. Le, the elution zone of assembly 28 is connected to the intake manifold 11 via

conduits

46, 48 and 49 (connected by respective ports of the valve 25b of FIG. 1), while the gas tank 21 is likewise connected to the manifold 11 via conduits 68a, valve 26c and

conduits

68b and 49. In that way, as desorption of the heavier compounds occurs, say as warmed gases are conveyed in heat transfer contact with the elution zone and the heavier compounds are swept into the intake manifold 11, there can be a simultaneous conveyance of evaporative emissions, if any, from the gas tank 21 to the manifold 11. With the desorption of heavier compounds within the elution zone, it should also be pointed out that vapors captured within the adjacent absorptive capture zone of the cannister assembly can likwise be purged. However, instead of the desorbed materials entering the manifold 11 below the air intake system, the captured evaporative emissions pass directly into air intake system 13 and thence to the manifold 11.

Where the heavier compounds within the elution zone of the cannister assembly 28 have relatively high,

44 and 55' of FIG. 4 can be renewed using the hot ex-' haust 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 bed comprising the elution zone 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 21 2 minutes in duration. The resulting desorbed aromatic compounds then pass through the air intake system to the combustion chambers where they are consumed.

While purging of evaporative emissions within the vapor adsorption zone of the cannister assembly 28 occur 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. Accordingly, the adsorbent material indicated at 55 in FIG. 2 and at 55' in FIG. 5 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 Charcoal Charcoal blacks Graphite Resins and Plastics Organic only Paraffins Stibnite Sulfides Metallic only Talc Even though the cannister assembly 28 of FIG. 4 is larger than that depicted in FIG. 2, it provides better heat transfer characteristics during desorption of the elution and vapor adsorption zones since the available heat transfer area (between the heat transferring me dia) is much larger. That is to say, the shell-side hot gases traveling through the cannister assembly 28 of FIG. 4 is in heat transfer contact with a multiplicity of the tubular member means, not just a single tubular means as in FIG. 2. Also, since temperature of the gases is much higher, the total purge time is greatly reduced. In this regard, the total flow rate of the hot purged gases at the air intake system should be carefully controlled so that the composite temperature of the inlet air is not too hot for efficient utilization of the resulting air fuel mixture within the combustion chamber of the engine.

FIG. 7 illustrates yet another mode for desorbing the elution and vapor adsorption zones of the cannister assembly of FIGS. 2 and 4. In accordance with the illustrated embodiment, engine air is heated by passing the air adjacent to exhaust manifold 130 and thence through the cannister assembly where desorption occurs.

In more detail, the exhaust manifold 130 is provided with an exterior hood 131 having lower skirts 132 which snuggly fit adjacent to the exhaust manifold, yet are open to incoming air. A central register 133 is also provided with a nozzle 134. Nozzle 134 in turn is attached by flexible conduit 135 connected at a port 136, say at the air intake line 13a of the air intake system of the embodiment of FIG. 2. At the air intake line 13a, a solenoid operator 137 is positioned so that damper 138 is in register with port 136. Opening the damper 138 allows warmed engine air to enter the cannister assembly (not shown).

FIGS. 8 and 9 depict the operation of the conduit and valve network 26 in detail. In FIG. 8, the inlet and outlet cold start valves 26a and 26b are seen to be in a relaxed state to allow utilization of the full-range fuel. In FIG. 9, the evaporative control valve 26c is in position to carry out the vapor adsorption control function of the present invention. That is to say, the evaporative control valve 26c is in a relaxed state so that its exhaust port 140 and inlet port 141 is in fluid communication with the gas tank 23. When the engine is in aninactive state, and evaporation of the fuel occurs, the vapors pass through the control valve 26c, and conduit 50 to the vapor adsorption zone of the cannister assembly 28 of FIGS. 2 and 4. Adsorption of the vapor prevents its escape into the atmosphere.

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.

I claim:

1. Apparatus for reducing exhaust and inoperative pollutants produced by a high speed injection system for a spark-ignition internal combustion engine of the type including a rotating shaft, an intake manifold, one or more cylinders each having an injection valve responsive to a control signal for injecting and mixing a predetermined quantity of full-range fuel with air to form a combustible mixture for delivery to said cylinders of said engine, and computing means including synchronization and condition means for controlling said injection valves through generation of said control signals as a function of one or more engine operating parameters, said synchronizing means being operatively connected to each of said injection valves for synchronizing operation thereof as a function of predetermined angular shaft position by generating a series of start signals for said injector valves, said condition means responsive to each of siid start signals as well as to signals indicative of other operating parameters, for controlling the duration of energization of said injection valves, comprising:

i. a cannister assembly containing adsorbent material (a) capable of selectively adsorbing high molecular weight constituents of said full-range fuel at cold start whilc eluting substantially unimpeded a cold start fuel effluent composed essentially of only low molecular weight constituents as well as (b) capa ble of selectively absorbing vapor constituents of said full-range fuel during an inoperative state of said engine,

tween said cannister assembly, said injector valves, said intake manifold and a reservoir means for said full-range fuel for providing selective flow of said fuel including said cold start fuel between said cannister assembly, said reservoir means and each of said injector valves, said network means including a first plurality of conduit and valve means including first and second valve means controlling flow relative to 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 cannister assembly and flow of said cold start fuel effluent from said cannister assembly to said each injector valve 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 each injector valve in sequence thereby 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 cannister assembly and said fuel reservoir means for selectively conveying vapor evaporative emissions of said fuel within said fuel reservoir to said cannister assembly, 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 injector valves as a function of one or more engine operating parameters.

2. Apparatus of claim 1 in which said cannister assembly includes an elongated tubular means disposed within an enlarged shell housing to form a shell-andtube arrangement for conduction of tube-side and shell-side fluids in adjacent but independent flow relationship, said tubular means including a central segment supporting a first bed of adsorbent material forming an elution zone for eluting low molecular weight cold start fuel, and separate inlet and outlet means connected to said reservoir and said each injector valve respectively, through said first and second valve means, so as to selectively deliver fuel to said each injector valves as a function of a selected engine parameter, said shell housing including a central portion forming a second bed of adsorbent material open at one end to atmosphere surrounding said engine and at another end connected to an intake manifold so as to guide at least a part of intake air adjacent to said each injector valve, and an entry vapor conduit means connected to said reservoir means through said third valve so as to allow selection vapor contact therebetween as a function of a selected engine parameter indicative of the inoperative state of said engine whereby evaporative emissions can be absorbed within said section adsorbent bed and do not escape into atmosphere surrounding said engine.

. valve and conduit network means attached be- I 3. Apparatus of claim 2, in which said elongated tubular means includes a singular .tubular conduit arranged within a single tubular shell housing, said single tubular conduit arranged to rigidly support said first bed of adsorbent material therein but having radially extending inlet and outlet conduit means in contact with first and second valve means respectivelyso as to allow only single pass flow of said full-range fuel relative to said shell having housing during cold start of said engine.

4. Apparatus of claim 2 in which said tubular means is a multiplicity of tubular conduits each arranged parallel to each other within a single tubular shell housing, each conduit supporting a segment of said first bed of adsorbent material but all terminating at central inlet and outlet chambers in operative contact with said first and second valve means, whereby full-range fuel percolating therethrough during cold starting of said engine is provided with a multiplicity of sinusoidal paths within said single enlarged tubular shell housing.

5. Apparatus of claim 1 in which said adsorbent materials within said first and second adsorbent beds are of different polarity classification.

6. Apparatus of claim 5 in which said first adsorbent bed is formed of a polar adsorbent material while said second adsorbent bed is formed of a nonpolar adsorbent material.

7. Apparatus of claim 2 in which said one end of said shell housing is connected by air intake control means including conduit means, to a source of heated gas, so as to allow selective flow of said heated gas through said cannister assembly for purging both first and second beds of adsorbed fuel constituents, said purged constituents from said first and second beds being carried into and consumed within said cylinders of said engine during normal running operation.

8. Apparatus of claim 2 inwhich said engine includes an air intake system comprising an air cleaner assembly having an air intake line and an air filter,said air intake line includingsupport means for rigidly supporting said cannister assembly in flow relationship with an intake manifold of said engine adjacent tov said injector valves.

Claims

1. Apparatus for reducing exhaust and inoperative pollutants produced by a high speed injection system for a spark-ignition internal combustion engine of the type including a rotating shaft, an intake manifold, one or more cylinders each having an injection valve responsive to a control signal for injecting and mixing a predetermined quantity of full-range fuel with air to form a combustible mixture for delivery to said cylinders of said engine, and computing means including synchronization and condition means for controlling said injection valves through generation of said control signals as a function of one or more engine operating parameters, said synchronizing means being operatively connected to each of said injection valves for synchronizing operation thereof as a function of predetermined angular shaft position by generating a series of start signals for said injector valves, said condition means responsive to each of siid start signals as well as to signals indicative of other operating parameters, for controlling the duration of energization of said injection valves, comprising: i. a cannister assembly containing adsorbent material (a) capable of selectively adsorbing high molecular weight constituents of said full-range fuel at cold start while eluting substantially unimpeded a cold start fuel effluent composed essentially of only low molecular weight constituents as well as (b) 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, said injector valves, said intake manifold and a reservoir means for said full-range fuel for providing selective flow of said fuel including said cold start fuel between said cannister assembly, said reservoir means and each of said injector valves, said network means including a first plurality of conduit and valve means including first and second valve means controlling flow relative to 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 cannister assembly and flow of said cold start fuel effluent from said cannister assembly to said each injector valve 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 each injector valve in sequence thereby 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 cannister assembly and said fuel reservoir means for selectively conveying vapor evaporative emissions of said fuel within said fuel reservoir to said cannister assembly, 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 injector valves as a function of one or more engine operating parameters.

2. Apparatus of claim 1 in which said cannister assembly includes an elongated tubular means disposed within an enlarged shell housing to form a shell-and-tube arrangement for conduction of tube-side and shell-side fluids in adjacent but independent flow relationship, said tubular means including a central segment supporting a first bed of adsorbent material forming an elution zone for eluting low molecular weight cold start fuel, and separate inlet and outlet means connected to said reservoir and said each injector valve respectively, through said first and second valve means, so as to selectively deliver fuel to said each injector valves as a function of a selected engine parameter, said shell housing including a central portion forming a second bed of adsorbent material open at one end to atmosphere surrounding said engine and at another end connected to an intake manifold so as to guide at least a part of intake air adjacent to said each injector valve, and an entry vapor conduit means connected to said reservoir means through said third valve so as to allow selection vapor contact therebetween as a function of a selected engine parameter indicative of the inoperative state of said engine whereby evaporative emissions can be absorbed within said section adsorbent bed and do not escape into atmosphere surrounding said engine.

3. Apparatus of claim 2, in which said elongated tubular means includes a singular tubular conduit arranged within a single tubular shell housing, said single tubular conduit arranged to rigidly support said first bed of adsorbent material therein but having radially extending inlet and outlet conduit means in contact with first and second valve means respectively so as to allow only single pass flow of said full-range fuel relative to said shell having housing during cold start of said engine.

8. Apparatus of claim 2 in which said engine includes an air intake system comprising 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 an intake manifold of said engine adjacent to said injector valves.