GB2115872A - IC engine fuel injection carburettor - Google Patents

Abstract

Fuel under pressure, e.g. 10 p.s.i, from an electronically controlled metering valve 74 is mixed with air from an inlet 90 and delivered downstream of the throttle valve 16 through outlets 96, 98, 100 in a tubular nozzle 92 extending transversely of the induction passage 14. The restriction 86 in the mixture flow path provides sonic velocity over the majority of engine operating conditions. <IMAGE>

Description

SPECIFICATION Fuel injection apparatus and system Field of Invention This invention relates generally to fuel injection systems and more particularly to fuel injection systems and apparatus for metering fuel flow to an associated combustion engine.

Background of the Invention Even though the automotive industry has over the years, if for no other reason than seeking competitive advantages, continually exerted efforts to increase the fuel economy of automotive engines, the gains continually realized thereby have been deemed by various governmental bodies as being insufficient.

Further, such governmental bodies have also arbitrarily imposed regulations specifying the maximum permissible amounts of carbon monoxide (CO), hydrocarbons (HC) and oxides of nitrogen (not) which may be emitted by the engine exhaust gases into the atmosphere.

Unfortunately, generally, the available technology employable in attempting to attain increases in engine fuel economy is contrary to that technology employable in attempting to meet the governmentally imposed standards on exhaust emissions.

For example, the prior art in trying to meet the standards for NOx emissions has employed a system of exhaust gas recirculation whereby at least a portion of the exhaust gas is reintroduced into the cylinder combustion chamber to thereby lower the combustion temperature therein and consequently reduce the formulation of NOx.

The prior art has also proposed the use of engine crankcase recirculation means whereby the vapors which might otherwise become vented to the atmosphere are introduced into the engine combustion chambers for further burning.

The prior art has also proposed the use of fuel metering means which are effective for metering a relatively overly rich (in terms of fuel) fuel-air mixture to the engine combustion chamber means as to thereby reduce the creation of NOx within the combustion chamber. The use of such overly rich fuel-air mixtures results in a substantial increase in CO and HC in the engine exhaust which,in turn, requires the supplying of additional oxygen, as by an associated air pump, to such engine exhaust in order to complete the oxidation of the CO and HC prior to its delivery into the atmosphere.

The prior art has also heretofore proposed employing the retarding of the engine ignition timing as a further means for reducing the creation of NOx. Also, lower engine compression ratios have been employed in order to lower the resulting combustion temperature within the engine combustion chamber and thereby reduce the creation of NOx. In this connection the prior art has employed what is generally known as a dual bed catalyst. That is,a chemically reducing first catalyst is situated in the stream of exhaust gases at a location generally nearer the engine while a chemically oxidizing second catalyst is situated in the stream of exhaust gases at a location generally further away from the engine and downstream of the first catalyst.The relatively high concentrations of CO resulting from the overly rich fuel-air mixture are used as the reducing agent for NOX in the first catalyst while extra air suppled (as by an associated pump) to the stream of exhaust gases, at a location generally between the two catalysts, serves as the oxidizing agent in the second catalyst. Such systems have been found to have various objections in that, for example, they are comparatively very costly requiring additional conduitry, air pump means and an extra catalyst bed. Further, in such systems, there is a tendency to form ammonia which, in turn, may or may not be reconverted to NOx in the oxidizing catalyst bed.

The prior art has also proposed the use of fuel metering injection means for eliminating the usually employed carbureting apparatus and, under superatmospheric pressure, injecting the fuel through individual nozzles directly into the respective cylinders of a piston type internal combustion engine. Such fuel injection systems, besides being costly, have not proven to be generally successful in that the system is required to provide metered fuel flow over a very wide range of metered fuel flows. Generally, those prior art injection systems which are very accurate at one end of the required range of metered fuel flows, are relatively inaccurate at the opposite end of that same range of metered fuel flows.Also, those prior art injection systems which are made to be accurate in the mid-portion of the required range of metered fuel flows are usually relatively inaccurate at both ends of that same range. The use of feedback means for altering the metering characteristics of such prior art fuel injection systems has not solved the problem of inaccurate metering because the problem usually is intertwined within such factors as: effective aperture area of the injector nozzle; comparative movement required by the associated nozzle pintle or valve member; inertia of the nozzle valving member; and nozzle "cracking" pressure (that being the pressure at which the nozzle opens). As should be apparent, the smaller the rate of metered fuel flow desired, the greater becomes the influence of such factors thereon.

It is anticipated that the said governmental bodies will be establishing even more stringent exhaust emission limits.

The prior art has suggested the employment of a "three-way" catalyst, in a single bed, within the stream of exhaust gases as a means of attaining such anticipated exhaust emission limits with respect to NOx Generally, a "three-way" catalyst is a single catalyst, or catalyst mixture, which catalyzes the oxidation of hydrocarbons and carbon monoxide and also catalyzes the reduction of oxides of nitrogen. It has been discovered that a difficulty with such a 'three-way" catalyst system is that if the fuel metering is too rich (in terms of fuel) the NOx will be reduced effectively but the oxidation of CO will be incomplete; if the fuel metering is too lean, the CO will be effectively oxidized but the reduction of NOx will be incomplete.Obviously, in order to make such a''three-way" catalyst system operative, it is necessary to have very accurate control over the fuel metering function of the associated fuel metering supply means feeding the engine. As hereinbefore described, the prior art has suggested the use of fuel injection means, employing respective nozzles for each engine combustion chamber, with associated feedback means (response to selected indicia of engine operating conditions and parameters) intended to continuously alter or modify the metering characteristics of the fuel injection means. However, as also hereinbefore indicated, such fuel injection systems have not proven to be successful.

It has also heretofore been proposed to employ fuel metering means, of a carbureting type, with feedback means responsive to the presence of selected constituents comprising the engine exhaust gases. Such feedback means were employed to modify the action of a main metering rod of a main fuel metering system of a carburetor. However, tests and experience have indicated that such a prior art carburettor and such a related feedback means can never provide the degree of accuracy required in the metering of fuel to an associated engine as to assure meeting, for example, the said anticipated exhaust emission standards.

Further, various prior art structures have experienced problems in being able to supply metered fuel, at either a proper rate or in a proper manner, as to provide for a smooth engine and/or vehicle acceleration when such is demanded.

Accordingly, the invention as disclosed and described is directed, primarily to the solution of such and other related and attendant problems of the prior art.

Summary of the Invention According to the invention, a fuel metering apparatus for supplying metered rates of fuel flow to a combustion engine, comprises body means, induction passage means formed through said body means for supplying motive fluid to said engine, throttle valve means situated in said induction passage means for variably controlling the rate of flow of air through said induction passage means, fuelair mixture discharge means situated in said induction passage means downstream of said throttle valve means, air passage means communicating between a source of air and said fuel-air mixture discharge means, and fuel metering means for metering liquid fuel under superatmospheric pressure in response to engine demands and indicia of engine operation, said liquid fuel when metered by said fuel metering means being discharged into said air passage means at an area thereof downstream of said source of air and upstream of said fuel-air mixture discharge means, said fuel-air mixture discharge means comprising conduit means extending generally transversely of said induction passage means, and a plurality of discharge ports formed in said conduit means for communicating said fuel-air mixture to said induction passage means.

Various general and specific objects, advantages and aspects of the invention will become apparent when reference is made to the.

following detailed description considered in conjunction with the accompanying drawings.

Brief Description of the Drawings In the drawings wherein for purpose of clarity certain details and/or elements may be omitted: Figure 1 illustrates in cross-section one form of the fuel injection apparatus and system employing teachings of the invention; and Figure 2 is a block diagram of an entire fuel metering system as may be applied to or employed in combination with the fuel injection apparatus of Fig. 1.

Detailed Description of the Preferred Embodiment Referring now in greater detail to the drawings, Fig. 1 illustrates fuel injection apparatus 10 and system comprised as of induction body or housing means 1 2 having induction passage means 14 wherein a throttle valve 1 6 is situated and carried as by a rotatable throttle shaft 1 8 for rotation therewith thereby variably restricting the flow of air through the induction passage means 1 4 and into the engine 20 as via associated engine intake manifold means 22. If desired suitable air cleaner means may be provided as to generally encompass the inlet of induction passage means 14 as generally fragmentarily depicted at 24. The throttle valve means 1 6 may be suitably operatively connected as through related linkage and motion transmitting means 26 to the operator positioned throttle control means which, as generally depicted, may be the operator foot-operated throttle pedal or lever 28 as usually provided in automotive vehicles.

A source of fuelas, for example, a vehicular gasoline tank 30, supplies fuel to associated fuel pumping means 32 which, in turn, deiiv- ers unmetered fuel as via conduit means 34 to conduit means 36 leading as to a chamber portion 38 which, in turn, communicates with passage or conduit means 40 leading to pressure regulator means 42. As generally depicted; the pressure regulator means 42 may comprise a recess or chamber like portion 44 formed-in body- 12 and a cup-like cover member 46.A deflectable diaphragm 48, -operatively secured as to the stem portion 50 of a valving member 52 as through opposed diaphragm; backing plates 54 and 56, is generally peripherally contained and retained between cooperating portions of body 12 and cover 46.as to thereby define variable and -distinot-chambers-44 and 58 with chamber 58 being vented as to a source of ambient atmosphere- pressure as through vent or passage means 60 A valve seat or orifice mem ber 62 cooperates with valving member 52 forscontrollably allowing flow of fuel thereby between and into passage means .64 and fuel returri conduit- means: 66 which, as depicted, preferably returns the excess fuel to the fuel supply means 30. Spring means 68 situated as within chamber means 58 operatively en gages diaphragm means 48 and resiliently urges valving member 5-2 closed against valve seat 62.

Generally, unmetered fuel may be provided to conduit means 36 and chamber 38 at a pressure of, for example, slightly in excess of 10.0 p.s.i. Passage 40 communicates such pressure to chamber 44 where it acts against diaphragm 48 and spring means 68- which are selected as to open valving member 52 in order to-thereby vent some-of-the fuel and pressure as to maintain an unmetered fuel pressure of 0.0 p.s.i.

Chamber-38 is, at times, placed in com munication with metered fuel passage means 70 as through metered fuel orifice means 72.

As depicted, a metering valving member 74 is adapted-toat times be seated as against a suitable seating surface 76 thereby terminat ing fuel flow from chamber 38 through pas sage means 72 and. into passage means 70.

Passage means 70 may also contain therein converging or venturi means 78 which may take the form of an insert like member having a body 80 with a venturi passage 82 formed therethrough as to have a converging inlet or upstream surface portion 84 leading to a venturi throat 86 from which a conduit means 87 extends downstream. A conduit 88 having one end 90 communicating as with a source of ambient atmosphere has its other end com municating with metered fuel passage means 70 as at a point or area upstream of venturi restriction means 78 and, generally, down stream of metered fuel passage means 72.

A metered fuel discharge nozzle means is preferably formed as a conduit-like member 92 which has its inner end 94 received by restriction means 78 as to effectively have the interior thereof a continuation of the conduit or passage means 87 of restriction means 78.

The metered fuel distribution means or fuel nozzle bar means 92, in the preferred embodiment, comprises a plurality of selectively located, positioned and calibrated discharge orifice means which, as generally depicted, may comprise a lower disposed discharge orifice means 96, a plurality of generally side-ways directed discharge orifice means two of whichare depicted at 98, and end discharge orifice means as at 100. Although the practice of the invention is not so limited, in the preferred embodiment, the bar nozzle means 92, in transverse cross-section, is of tubular cylindrical configuration.

Valve member 74 is illustrated as comprising a portion of an overall oscillator type valving means or.assembly 104 which is depicted as comprising a spool-like bobbin 106 having inner passage means -108-slidably receiving. therein an armature. means 110, carrying valve member 74, and spring means 11 2 yieldingly urging armature 110 and valve member 74 generally toward the left and into seated engagement with valve seat means 76 terminating communication of. chamber 38 with passage or conduit means 72.A field or solenoid winding or coil 114 is carried by the bobbin 106 and has its opposite electrical ends connected as to electrical conductors 116 and 118 which may pass through suitable closure means 120 and be electrically connected as to related control means 1 22.

The practice of the invention is not limited to; for example, a particular fuel metering means; however, in the preferred embodiment, the metering valving means 104 is of the. duty cycle.type wherein the winding 114 is intermittently energized thereby causing, during such energization, armature 110 and valve member 74-to move in a direction away from valve orifice 72 or valve seat 76. As should be apparent, with such a duty-cycle type metering solenoid assembly the effective flow area of valve orifice or passage 72 can be variably and controllably determined-by controlling the frequency and/or duration of the energization of coil means 114.

The control means 1 22 may comprise, for example, suitable electronic logic type control and power output means effective to receive one or more parameter type input signals and in response thereto produce related outputs.

For example, engine temperature responsive transducer means 1 24 may provide a signal via transmission means 1 26 to control means 1 22 indicative of the engine temperature; sensor means 1 30 may sense the relative oxygen content of the engine exhaust gases (as within engine exhaust conduit means 132) and provide a signal indicative thereof via transmission means 1 34 to control means 122; engine speed responsive transducer means 1 36 may provide a signal indicative of engine speed via transmission means 1 38 to control means 1 22 while engine load, as indicated for example by throttle valve 1 6 position, may provide a signal as via transmission means 140 to control means 1 22. A source of electrical potential 142 along with related switch means 1 44 may be electrically connected as by conductor means 146 and 1 48 to control means 1 22.

Operation of Invention Generally, in the embodiment disclosed, fuel under pressure is supplied as by fuel pump means 32 to conduit 36 and chamber 38 (and regulated as to its pressure by regulator means 42) and such fuel is metered through the effective metering area of valve orifice means 72 to conduit portion 70 from where such metered fuel flows through restriction means 78 and into bar discharge nozzle means 92 and ultimately through discharge port means 96, 98 and 100 and to the engine 20. The rate of metered fuel flow, in the embodiment disclosed, will be dependent upon the relative percentage of time, during an arbitrary cycle time or elapsed time, that the valve member 74 is relatively close to or seated against orifice seat 76 as compared to the percentage of time that the valve member 74 is relatively far away from the cooperating valve seat 76.

This, in turn, is dependent on the output to coil 114 from control means 1 22 which, in turn, is dependent on the various parameter signals received by the control means 1 22.

For example, if the oxygen sensor and transducer means 1 30 senses the need of a further fuel enrichment in the motive fluid being supplied to the engine and transmits a signal reflective thereof to the control means 122, the control means 122, in turn, will require that the metering valve 74 be opened a greater percentage of time as to provide the necessary increased rate of metered fuel flow.

The practice of the invention is not limited to a particular form of fuel metering means or to a particular system for the control of such fuel metering means. Accordingly, it will be understood that given any selected parameters and /or indicia of engine operation and/or ambient conditions, the control means 1 22 will respond to the signals generated thereby and respond as by providing appropriate energization and de-energization of coil means 114 (causing corresponding movement of valve member 74) thereby achieving the then required metered rate of fuel flow to the engine.

The prior art has employed relatively high pressures both upstream and downstream of the fuel metering means in an attempt to obtain sufficient fuel atomization within the induction passage means. Such have not proven to be successful.

It has been discovered that the invention provides excellent fuel atomization characteristics even when the upstream unmetered fuel pressure is in the order of 10.0 p.s.i. (the prior art often employing upstream unmetered fuel pressures in the order of 40.0 p.s.i.). The invention achieves this by providing a high velocity air stream into which all the metered fuel is injected, mixed and atomized and subsequently delivered to the engine induction passage.

That is, more particularly, in the preferred embodiment, conduit means 88 supplies all of the air needed to sustain idle engine operation when the throttle valve means 1 6 is closed.

As can be seen a flow circuit is described by inlet 90 of conduit 88, conduit 88, passage means 70, passage means 87, orifice means 96, 98 and 100 and engine intake manifold induction passage means 13; such, in the preferred embodiment of the invention, provides all of the air flow to the engine 20 required for idle engine operation. The resistriction means 78 is of a size as to result in the flow through throat 86 being sonic during idle engine operation. The fuel which is metered by valve member 74 and injected into passage 70 mixes with the air as the metered fuel and air flow into inlet 84 of venturi restriction means 78 and become accelerated to sonic velocity. The fuel within such fuel-air mixtures becomes atomized as it undergoes acceleration to sonic velocity.The atomized fuel-air mixtures then passes into passage 87 of fuel distribution nozzle means 92 and is discharged, generally radially and axially thereof into induction passage means 14, through the discharge port means 96, 98 and 100 and into passage means 1 3 of engine 20. In the preferred embodiment of the invention, the restriction means 78 not only provides for sonic flow therethrough during idle engine operation but also provides for sonic flow therethrough during conditions of engine operation other than idle and, preferably, over at least most of engine range of engine operation.

When further engine power is required, throttle valve means 1 6 is opened to an appropriate degree and the various related parameter sensing means create input signals to control means 1 22 resulting in fuel metering means 104 providing the corresponding increase in the rate of metered fuel to the passage 70 and, as hereinbefore described, ultimately to engine 20.

As should be apparent, suitable temperature responsive means may be provided in order to slightly open throttle valve 1 6 during cold engine idle operation in order to thereby assist in sustaining such cold engine idle operation and preclude rough engine operation.

It can be seen that in the preferred embodiment the diffuser or discharge nozzle means 92 is comprised of a plurality of spaced discharge ports or apertures which are also influenced by the air flow permitted by throt tle valve means 1 6. That is, the more that throttle valve 1 6 is opened the greater will be the velocity of air flow and, as a consequence of such flow around the bar fuel discharge means 92, a degree of vacuum will be created in the vicinity of the various discharge port means (96, 98, 100) thereby further enhancing the flow of atomized fuel air through such discharge port means and into the induction passage means 1 4. Further, in the preferred embodiment at least a major portion of the metered fuel distribution bar means 92 which extends into the induction passage means 1 4 is positioned as to be generally aligned with the major diameter of induction passage means 14 and generally normal to the axis of flow through induction passage means 14.

It has been discovered that problems of engine hesitation otherwise usually encountered when sudden engine acceleration or sudden loads are placed on the engine are effectively overcome by the use of such bar type metered fuel distribution means 92 placed within the general confines of the induction passage means.

It should be apparent that the actual number and configuration of the aperture or port means 96, 98 and 100 are not restricted to that depicted nor to being cylindrical. It is contemplated that in some applications of the invention it may be desirable to provide particularly tailored configurations of such discharge port means 96, 98 and 100 as well as possibly providing a plurality of, for example, closely grouped discharge ports or apertures.

Fig. 2 illustrates in general block diagram the invention of Fig. 1 along with other contemplated operating parameter and indicia sensing means for creating related inputs to the control means which, as generally identified in Fig. 2, may be an electronic control unit. For ease of reference, elements in Fig. 2 which correspond to those of Fig. 1 are identified with like reference numbers provided with a suffix "a".

As generally depicted in Fig. 2 the electronic control or logic means 1 22a is illustrated as receiving input signals, as through suitable transducer means, reflective and indicative of various engine operating parameters and indicia of engine operation. For example, it is contemplated that the electronic logic or control means 1 22a would receive, as inputs, signals of the position of the throttle valve means 1 6a as via transducer or transmission means 140a; the magnitude of the engine speeds as by transducer or transmission means 138a; the magnitude of the absolute pressure within the engine intake manifold 22 as by transducer or transmission means 1 50; the temperature of the air at the inlet of the induction system as by transducer or transmission means 152; the magnitude of the engine 20a coolant system temperature as via transducer or transmission means 126; the magnitude of the engine exhaust catalyst 1 54 temperature as by transducer or transmission means 156; and the percentage of oxygen (or other monitored constituents) in the engine exhaust as by transducer or transmission means 134a.

In considering both Figs. 1 and 2 it can be seen that the electronic control means 122a, upon receiving the various input signals, creates a first output signal as along conductor means 11 6a and 11 8a thereby energizing fuel metering valving means 1 04a. If the operator should open throttle valve means 16a, as through pedal 28a and linkage or transmission means 26a, the new position thereof is conveyed to the control means 1 22a and an additional rate of air flow 1 58 is permitted into the induction passage means 1 4a as to become commingled with the motive fluid being discharged by the bar nozzle means 92.

In any event, the fuel-air mixture is introduced into the engine 20a (as via intake manifold means 22) and upon being ignited and performing its work is emitted as exhaust.

An oxygen or other gas sensor, or the like, 1 30a monitors the engine exhaust gases and in accordance therewith creates an output signal via transducer means 1 34a to indicate whether the exhaust gases are overly rich, in terms of fuel, too lean, in terms of fuel, or exactly the proper ratio. The electronic control means, depending upon the nature of the signal received from the gas sensor 1 34a, produced an output signal as via conductor means 11 6a and 11 8a for either continuing the same duty cycle of fuel metering valve means 1 04a or altering such as to obtain a corrected duty cycle and corresponding altered rate of metered fuel flow.Generally, each of such input signals (varying either singly or collectively) to the electronic control means (except such as will be noted to the contrary) will, in turn, cause the electronic control means 1 22a to produce an appropriate signal to the fuel metering valve assembly 104a.

As is also best seen in Fig. 2, in the preferred embodiment, a fuel supply or tank 30a supplies fuel to the inlet of a fuel pump 32a (which may electrically driven and actually be physically located within the fuel tank means 30a) which supplies unmetered fuel to suitable pressure regulator means 42a which is generally in parallel with fuel metering valving assembly 104a. Return conduit means 66a serves to return excess fuel as to the inlet of pump 32a or, as depicted, to the fuel tank means 30a. Fuel, unmetered, at a regulated pressure is delivered via conduit means 36 to the upstream side of the effective fuel metering orifice as determined by orifice means 72 and coacting valving member 74.

In practicing the invention, it is contem plated that certain fuel metering functions may be or will be performed in an open loop manner as a fuel schedule which, in turn, is a function of one or more input signals to the control means 122a. For example, it is contemplated that acceleration fuel could be supplied and metered by the fuel metering valving assembly 1 04a as function of the position of throttle valve means 1 6a and the rate of change of position of such throttle valve means 1 6a while the engine cranking or starting fuel and cold engine operation fuel metering schedule could be a function of engine temperature, engine speed and intake manifold pressure. Further, it is contemplated that open loop scheduling of metered fuel flow would be or could be employed during catalytic converter warm-up and for maximum engine power as at wide open throttle conditions as well as being employed during and under any other conditions considered necessary or desirable.

Although only a preferred embodiment and selected modifications of the invention have been disclosed and described, it is apparent that other embodiments and modifications of the invention are possible within the scope of the appended claims.

Claims (21)

1. Fuel metering apparatus for supplying metered rates of fuel flow to a combustion engine, comprising body means, induction passage means formed through said body means for supplying motive fluid to said engine, throttle valve means situated in said induction passage means for variably controlling the rate of flow of air through said induction passage means, fuel-air mixture discharge means situated in said induction passage means downstream of said throttle valve means, air passage means communicating between a source of air and said fuel-air mixture discharge means, and fuel metering means for metering liquid fuel under superatmospheric pressure in response to engine demands and indicia of engine operation, said liquid fuel when metered by said fuel metering means being discharged into said air passage means at an area thereof downstream of said source of air and upstream of said fuel-air mixture discharge means, said fuel-air mixture discharge means comprising conduit means extending generally transversely of said induction passage means, and a plurality of discharge ports formed in said conduit means for communicating said fuel-air mixture to said induction passage means.

2. Fuel metering apparatus according to claim 1 wherein said air passage means comprises flow restriction means, and wherein said flow restriction means is calibrated as to provide for sonic flow therethrough for at least certain conditions of engine operation.

3. Fuel metering apparatus according to claim 2 wherein said flow restriction means comprises venturi type restriction means.

4. Fuel metering apparatus according to claim 1 wherein said air passage means comprises flow restriction means, and wherein said flow restriction means is calibrated as to provide for sonic flow therethrough during at least idle engine operation.

5. Fuel metering apparatus according to claim 4 wherein said flow restriction means comprises venturi type restriction means.

6. Fuel metering apparatus according to claim 2 wherein said conduit means extends into and generally transversely of said induction passage means, wherein said conduit means comprises first and second conduit ends, wherein said first conduit end is in fluid communication with said restriction means as to thereby receive the fuel-air mixture flowing through said restriction means, wherein said plurality of discharge port means comprises first and second discharge port means, wherein said first discharge port means are formed in said conduit means as to direct discharge flow therefrom in directions generally transverse to said conduit means, and wherein said second discharge port means is formed in said second conduit end as to direct discharge flow therefrom in a direction generally axially of said conduit means.

7. Fuel metering apparatus according to claim 2 wherein said conduit means extends into and generally transversely of said induction passage, wherein said conduit means comprises first and second conduit ends, wherein said first conduit end is in fluid communication with said restriction means at generally one side of said induction passage means as to thereby receive the fuel-air mixture flowing through said restriction means, and wherein said second conduit end is situated within said induction passage means and spaced from the side of said induction passage means generally opposite to said one side.

8. Fuel metering apparatus according to claim 2 wherein said conduit means extends into and generally transversely of said induction passage means, wherein said conduit means comprises first and second conduit ends, wherein said first conduit end is in fluid communication with said restriction means as to thereby receive the fuel-air mixture flowing through said restriction means, wherein said plurality of discharge port means comprises first port means formed generally through the lateral side of said conduit means as to direct discharge flow therefrom in directions generally laterally transversely of said conduit means, and wherein said plurality of discharge port means further comprises second port means formed generally through a downward downstream of said conduit means.

9. Fuel metering apparatus according to claim 8 wherein said second port means is located as to be generally between said first port means and said first conduit end.

10. Fuel metering apparatus according to claim 8 wherein said plurality of discharge port means further comprises third port means formed generally through said second conduit end of said conduit means as to direct discharge flow therefrom in a direction generally axially of said conduit means.

11. Fuel metering apparatus according to claim 8 wherein said second port means is located as to be generally between said first port means and said first conduit end, and wherein said plurality of discharge port means further comprises third port means formed generally through said second conduit end of said conduit means as to direct discharge flow therefrom in a direction generally axially of said conduit means.

1 2. Fuel metering apparatus according to claim 1 wherein said air passage means comprises flow restriction means, said flow restriction means being calibrated as to provide for sonic flow therethrough at conditions of idle engine operation, wherein said liquid fuel when metered by said fuel metering means is discharged not only upstream of said fuel-air mixture discharge means but also upstream of said flow restriction means, said flow restriction means comprising sonic venturi type restriction means, said fuel metering means for metering liquid fuel comprising a duty-cycle type metering solenoid assembly, said metering solenoid assembly comprising armature means, a valve member operatively positioned by said armature means, a field winding, said field winding being intermittently energizable during metering of said liquid fuel as to cause said armature means and said valve member to move toward and away from a closed position and thereby result in an average rate of flow of fuel past said valve member which constitutes the then metered rate of liquid fuel flow, unmetered fuel passage means for supplying unmetered fuel to said fuel metering means upstream of said fuel metering means, pressure regulator means operatively communicating with said unmetered fuel for regulating the pressure thereof to a preselected superatmospheric magnitude, said conduit means comprising a generally tubular member communicating with said venturi type restriction means and extending into said induction passage means, and a plurality of discharge port means formed through said tubular member and communicating with said induction passage means for directing the flow of the fuel-air mixture within said tubular member to said induction passage means.

1 3. Fuel metering apparatus according to claim 1 2 wherein said sonic venturi restriction means comprises an upstream situated converging section, and wherein said tubular member is in communication with said sonic venturi restriction means at a point downstream of said converging section.

14. Fuel metering apparatus according to claim 1 2 wherein said tubular member extends into and generally transversely of said induction passage means, wherein said tubular member comprises first and second tubular ends, wherein said first tubular end is in fluid communication with said venturi type restriction means as to thereby receive the fuel-air mixture flowing through said venturi type restriction means, wherein said plurality of discharge port means comprises first and second discharge port means, wherein said first discharge port means are formed in said tubular member as to direct discharge flow therefrom in directions generally transverse to said tubular member, and wherein said second discharge port means is formed in said second tubular end as to direct discharge flow therefrom in a direction generally axially of said tubular member.

1 5. Fuel metering apparatus according to claim 1 2 wherein said tubular member extends into and generally transversely of said induction passage means, wherein said tubular member comprises first and second tubular ends, wherein said first tubular end is in fluid communication with said venturi type restriction means at generally one side of said induction passage means as to thereby receive the fuel-air mixture flowing through said venturi type restriction means, and wherein said second tubular end is situated within said induction passage means and spaced from the side of said induction passage means generally opposite to said one side.

16. Fuel metering apparatus according to claim 1 2 wherein said tubular member extends into and generally transversely of said induction passage means, wherein said tubular member comprises first and second tubular ends, wherein said first tubular end is in fluid communication with said venturi type restriction means as to thereby receive the fuel-air mixture flowing through said venturi type restriction means, wherein said plurality of discharge port means comprises first port means formed generally through the lateral side of said tubular member as to direct discharge flow therefrom in directions generally laterally transversely of said tubular member, and wherein said plurality of discharge port means further comprises second port means formed generally through a downward downstream side of said tubular member as to direct discharge flow therefrom in a direction generally downward downstream of said tubular member.

1 7. Fuel metering apparatus according to claim 1 6 wherein said second port means is located as to be generally between said first port means and said first tubular end.

1 8. Fuel metering apparatus according to claim 1 6 wherein said plurality of discharge port means further comprises third port means formed generally through said second tubular end of said tubular member as to direct discharge flow therefrom in a direction generally axially of said tubular member.

19: Fuel metering apparatus according to claim- 16 wherein said second port means is located as to be generally between said first port means and said first tubular end, and wherein said plurality of discharge port means further comprises third port means formed generally through said second tubular end of said tubular member as to direct discharge flow therefrom in a direction generally axially of said tubular member.

20. Fuel metering apparatus substantially as hereinbefore described with reference to, and as illustrated in, the accompanying diagrammatic drawings.

21. Any features of novelty, taken singly or in combination, of the fuel metering apparatus as hereinbefore described wth reference to the-accompanying diagrammatic drawings.