US2788082A - Fuel injection system - Google Patents

Description

April 9, 1957 A. G. H. V ANDERPOEL 2,788,082

Y FUEL INJECTION SYSTEM I 2 Sheets-Sheet 1 Filed Oct. 1 1954 x I 2: v

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April 9, 1957 A. a. H. VANDERPOEL 2,788,082

FUEL. INJECTION SYSTEM Filed Oct. 18, 1954 2 Sheets-Sheet 2 ATTOEA/EY.

United States Patent FUEL INJECTION SYSTEM Albert G. H. Vanderpoel, Gardena, Calif.

Application October 18, 1954, Serial No. 462,951

21 Claims. (Cl. 183--14) This invention relates to air-fuel supply systems for internal combustion engines, and more particularly has to do with apparatus external to such engines for combining cleaned air with injected fuel in such a way as to obtain improved mixing of fuel and air, having the effect of improving the distribution of fuel and air to the engine cylinders.

An appreciation of the objects and advantages of the novel air-fuel supply system to be described will be more easily gained after certain of the limitations of known systems have been reviewed. As has been realized in the past, ordinary suction-type carburetor systems in which fuel droplets are entrained in air flowing to an engine are subject to disadvantages having to do with poor fuel vaporization and mixture distribution, resulting in unequal distribution of the air-fuel mixture to the engine and consequent starving of the leanest cylinders. More importantly, the problems of mixture distribution have had to be considered and dealt with in that phase of carburetion having to do with the formation of desired maximum economy air-fuel mixtures at intermediate loads between idling and wide-open throttle engine operating conditions.

In order to overcome air-fuel distribution problems, various expedients that have been proposed and adopted have included the provision of hot spots on the manifold to help vaporize the fuel, richening the overall mixture to obtain the proper air-fuel ratio at the leanest cylinders, and the use of small manifold and carburetor throats to increase air velocities so as to aid atomization of liquid fuel in the air. While these and other expedients have been partially successful in obtaining better mixture distribution, they do not, for various reasons, give fully satisfactory results. For example, gains in fuel atomization sought through the use of small carburetor throats such as venturis are achieved only at the expense of air-flow restriction in the carburetor, with consequent decreased horsepower output of the engine.

Another approach to the problem has led to the development of devices for injecting fuel directly into engine combustion chambers; however, certain critical requirements necessarily imposed upon such injectors to a large extent off-set the advantages accruing from the elimination of mixture distribution problems resulting from their use. For example, such injectors must be made to Withstand fluid pressures which increase rapidly with engine speeds, varying in proportion to the square thereof. Furthermore, combustion chamber fuel injectors are normally extremely complicated devices and are therefore subject to frequent marl-functioning.

The present invention has been predicated on the concept of providing thorough mixing of fuel with clean air prior to entrance of the mixture into the engine combustion chamber, so as to realize desirable air-fuel distribution to the various cylinders, with consequent increased smoothness in engine operation, more rapid throttle response, and increased fuel economy. In accordance with the invention, improved means are provided for thoroughly mixing pressurized fuel with clean air flowing to the engine in the proper air-fuel ratio over the normal range of engine operating conditions. More particularly, it is contemplated to effect continuous injection of liquid fuel into a stream of cleaned air passing through a turbulent air-fuel mixing zone, and subsequently to conduct the resultant mixture through a mixing passage leading to the engine manifold, so that the air-fuel mixture will be in condition favoring equal distribution thereof to the engine cylinders. Provision is also made for injecting pressurized fuel at a rate which varies in accordance with changes in the air-flow rate, so as to maintain desirable air-fuel ratios for maximum economy. Since thorough air-fuel mixing is achieved by injection technique, the air-flow passages may be widened or openedup to minimize air-flow restrictions, resulting in greater air-fuel intake and increased horsepower development by the engine.

In carrying out these purposes, a chamber is provided external to the mixing passage, and an air cleaner is positioned in the chamber preferably at the side of the mixing passage walls, so that the air must reverse its flow direction after passing through the cleaner in order to enter the passage. A fuel-air mixing zone is advantageously located in the chamber between the cleaner and the inlet to the mixing passage wherein the air is caused to reverse its flow direction with resultant turbulence. Fuel is injected upstream into the mixing zone so as to take maximum advantage of air turbulence existent therein, aiding atomization and mixing of the fuel with air. I

Desirable air-fuel ratios are maintained by means of a pressure sensitive movable diaphragm located in the mixing zone and forming a wall toward which air flows prior to reversing its direction. The diaphragm moves in accordance with pressure changes to vary the crosssectional area of the zone through which air must flow,

to aid air-fuel mixing at higher engine speeds, and also operates upon the injector valve to increase or decrease the quantities of pressurized fuel being injected into the mixing zone, for the purpose of maintaining desired airfuel ratios. The geometry of the mixing zone, diaphragm, and injector is preferably such as to cause fuel to be injected toward the diaphragm structure and to be deflected off the surface thereof to enhance fuel-air mixing.

In keeping with the provision of a complete air-fuel supply system operative to deliver desired mixtures over the complete range of engine operating conditions, a throttle is provided in the mixing passage to regulate the speed of the engine, and since operation of the fuel injection apparatus is preferably restricted to non-idling engine operation, idle jet structure is provided at the outlet side of the throttle to deliver fuel to the mixing passage during engine idling.

Fuel is delivered to both the idle jet and the fuel injector nozzle from a pressure regulator, the delivery pressure of which may be modified in accordance with desired engine power development. In particular, a pressure regulator valve is provided in a fuel flow passage, and the valve opening is caused to be increased not only in response to decreased delivered fuel pressure, corresponding to increased opening of the injection valve, but also in response to increased absolute pressure of the air-fuel mixture flowing from the throttle to the engine. This arrangement tends to provide higher fuel pressures at the fuel injection nozzle to maintain eflicient injection, in spite of increased nozzle opening, at time when greater engine power is sought to be developed. In addition, this arrangement furnishes quicker throttle response, since the control is directly sensitive to increased air-fuel mixture pressures between the throttle and the engine, corresponding to increased throttle opening.

included in this invention is a means for Obtaining quick opening of the fuel injector valve in order to effect the rapid formation of a rich air-fuel mixture for fast engine acceleration. To this end there. is provided a piston shdable in a chamber communicating with the engine manifold and operative to displace the diaphragm assembly. During normal engine operation the piston is held in a first position against the force of a, spring by suction pressure of the air-fuel mixture, which is communicable to the piston from a point between the throttle and the engine. However, when the throttle, is opened, the mixture pressure rises and allows the spring to quickly urge the piston in a diaphragm displacing direction; to effect rapid opening of the injector valve.

All the various features and objects of the. invention, as well as the details of anillustrative embodiment, will appear more fully understood from. the following descripn f the c ompany ng. r wings, in whi h:

Fig. 1' is an elevation taken in sectionithrough the preferred embodiment of, the invention;

Fig. 2 is a two-part enlarged view of the idle jet assembly, showing two operative positions thereof;

Fig. 3 is an elevation taken in section through a modified form of the invention, including a sectional view of fuel pressure regulator; and

Fig. 4 is an enlarged view of a solenoid controlled fuel valve for the fuel supply system.

In Fig. 1 there is shown an air-fuel intake manifold for an internal combustion engine, with a short ducted carburetor fitting 11- .connected into themanifold. To the flange 12 of this fitting there is joined by means of bolts 13 a flange 14 of an upright barrel or tube 15. The lower portion of this tube contains, a passage 16 which is narrowed to the diameter of the duct in the standard carburetor fitting 11,. the upper portion of the tube containing an enlarged diameter passage 19. The walls of the two straight passages. 16 and 19 are conveniently merged by a sloped wall 20 extending therebetween and pivoted throttle valve 17 is conveniently located in passage 16. As shown in the drawing, the, upper portion of the tube 15 projects upwardly through the closed base 21 of a receptacle or shell 22 having a cylindrical skirt 23 spaced outwardly from the tube. The base 21 of the receptacle may be bulged downward to provide a recess in which foreign particles may be collected, as will be described.

The upper portion of, the tube 15 carries anoutwardly and upwardlycurved mouthpiece 24. forming a rounded approach orifice 25 at the mouth or inlet of the tube. To this mouthpiece there is conveniently joined the base 26 of a second and smaller receptacle or shell 27 having a cylindrical skirt 28 positioned between the mouthpiece 24 and receptacle skirt 23. A passage or chamber 29 formed between the two receptacles communicates with chamber 30 within receptacle 27 through perforations or openings 31 in the base 26 thereof. In order that air passing through chambers 29 and 30 may be cleaned prior to entering passage 19 within the tube, an air cleaner comprising a mass 32 of foraminous material may be placed in one of the the chambers 29 or 30, as for example between skirt 28 and mouthpiece 24. Oil may also or alternatively be contained within the lower. portion of receptacle 22 to provide a type of oil bath air cleaner at the location where air reverses its flow direction to enter chamber 30. Foreign particles separated from the air stream reversing direction at the bottom of chamber 29 are conveniently collected in the recessed base 21 of re.- ceptacle 22.

Above the two receptacles 22 and 27, there is positioned a transversely extending head assembly 33 held against the rim of skirt 28, which projects upward beyond the rim of skirt 23, to provide an annular air, passage 34 communicating with chamber 29. Included in the assembly is a ring 35 containing an annular gasket36 engaging the rim of. skirt. 28, when the head assemblyis, held, in,

position over receptacle 27. Ring 35 is connected to the flanged portion 37 of a dome 38, and the flange is gripped by the jaws 39 of over-center clamps 40 joined to receptacle 22.

Connected across the upper portion of chamber 30 and spaced above the mouthpiece 24 and beneath dome 38 is a diaphragm assembly 41, including a movable diaphragm 42, the edge of which is clamped between ring 35 and flange 37, and upper and lower dished members 43 carried on opposite sides of the diaphragm. The diaphragm assembly is urged toward receptacle 27 by a compression spring 44 positioned between the dome 38 and the assembly 41, and also is retractable toward the dome by suction pressure existent within chamber 45, between the dome and the diaphragm assembly. Suction pressure is communicated from passage 16 to chamber 45 through line 46 connected to appropriate fittings 47 and 48, which are respectively threaded into opening 49 above throttle gate 17, and into opening 50 in dome 38..

Conveniently positioned between diaphragm assembly 41 and passage 19 is a fuel injector nozzle assembly 51 carried at the center of transverse support 52, which is connected to opposite sides of skirt 28. Arm 52a of the support contains a duct 53 for supplying fuel to the injector nozzle 51 from a T-fitting, which is in turn connected to a fuel pressure regulator 54 through a solenoid controlled valve 120. Nozzle 51 comprises a barrel 56 containing a fuel chamber or well 57 opening upwardly toward the diaphragm assembly 41. Threaded within chamber 57 is a jet part 58 containing an orifice 158 through which projects. a tapered pin 59 extending downward from a valve 60, which is carried by the diaphragm assembly. Spring44 urges the diaphragm assembly downward, forcing the. tapered seating surface of valve 60 toward an O-ring seat 61 positioned at the upper end of chamber 57. When the diaphragm assembly 41 is retracted upward by suction pressure in chamber 45, valve 63 moves away from O-ring seat 61, allowing pressurized fuel to be injected upward through orifice 158, past tapered valve 60 and radially outward into an air-fuel mixing zone 62 located beneath the diaphragm assembly and on both sides of the mouthpiece 24, where air ontrance velocities are somewhat reduced. The rate of fuel injection through orifice 158 is, of course, controlled by the size of the orifice opening as determined by the axial position of the tapered pin 59. Since the size of orifice 158 must be accurately controlled, the orifice is never closed by pin 59, and seating of valve 60 on O-ring 61 is depended upon to cut off fuel injection.

Pressurized fuel is also conducted through, line 65 from T-fitting 55 to an idle jet assembly 66, which is positioned in a thickened wall portion 67 of the-tube 15 near throttle gate 17, and is shown in an enlarged view in Fig. 2. The T-fitting may contain a suitable restriction through which pressurized fuel is delivered to idle jet assembly 66, for purposes to be described. Included in the jet assembly is an air-bleed check valve 63 carried in bore 69 and urged toward end wall 70 thereof by spring 170, the opposite end of which engages a snap ring 71 mounted in the bore. An aperture 171 in end wall 70 communicates pressure in passage 16 to the check valve 68. Also 1ncluded in the assembly is a fuel passage 72 in thickened portion 67 communicating between bore 69 and a second. bore 172 which is closed at one end by a threaded fitting 73 and open at the opposite end to define a small idle fuel passage orjet 74. The latter opens into passage 16 immediately below' the lip of throttle gate 17 when the gate is in closed position. The size of, idle passage 74 may be varied by a tapered pin 75 projecting through fitting 73 and into passage74, and having an external handle 76 attached to the outer end thereof for adjusting purposes.

When the engine is started, pressurized fuel is forced thru a suitable restriction in T-fitting 55,, and to idle.

jet.'. 4 viajeharnh r 5 and passage 72, check valve 63 avsspsa remaining closed against end wall 70 under the action of light compression spring 170 and the fuel pressure. At this time, the throttle 17 is partly opened to admit sufiicient air to mix with fuel discharging into passage 16 from idle jet 74.

During idling conditions the throttle 17 is closed and the pressure in chamber 69 is reduced by the communication of high manifold vacuum thereto thru passages 172 and 72 from idle jet 74 downstream of the throttle valve. As a result, the check valve 68 moves rightwardly off wall 70 as seen in Fig. 2(a) against spring 179, bleeding air at substantially atmospheric pressure from passage 16 through port 171 into chamber 69 where the air premixes with idle fuel and discharges at jet 74 downstream of the closed throttle.

As the throttle is gradually opened, the pressure in passage 16 upstream of the throttle decreases while the pressure in passage 16 downstream of the throttle increases along with the fuel pressure in line 65 and chamber 69, to the point where check valve moves leftward against wall 70, in Fig. 2(b), closing off the air bleed through port 171. Thereafter, fuel is delivered to idle jet 74 without simultaneous air bleed thereto.

During acceleration and full load, low manifold vacuum conditions exist, so that no air is bled to the idle jet and fuel is injected at 74 under full fuel pump pressure.

During engine running conditions other than idling, throttle 17 is partly or fully opened so that reduced pressure is communicated to the mixing passage 16 immediately above the throttle and to chamber 45 above the diaphragm assembly 41 via line 46. Under these circumstances, a condition of pressure unbalance is created on opposite sides of the diaphragm assembly, causing it to move upward, carrying valve 60 away from seat 61 and allowing pressurized fuel to escape therebetween and to be injected upward toward the diaphragm assembly and transversely outwardly, as controlled by the taper of the valve 60. The injected fuel particles are directed oppositely to the in-flowing, reduced velocity air-stream and become distributed therein in mixing zone 62 on opposite sides of mouthpiece 24. Any unmixed particles are suspended in the air filter 32 for subsequent entrainment by the infiowing clean air. Reduced pressure in passage 16 also induces air flow in greater quantities through chambers 29 and 3 in the receptacles toward orifice 25 at the mouth of mixing passage 19. Since air flowing from chamber 30 into mixing passage 19 must reverse its direction in the region of mixing zone 62, a condition of air turbulence is created in the latter zone favoring atomization and desirable distribution of the injected fuel in the air flowing through the mixing zone. In addition, injected fuel tends to impinge upon and to be deflected from the bottom surface of lower dished member 43, with the result that fuel particles are caused to be well distributed in the turbulent air passing through the mixing zone. Conditions favoring-further air-fuel mixing are set up in mixing passage 19 and passage 16, through which the air-fuel mixture is subsequently conducted. By proper proportioning of the diaphragm assembly 41, chamber 39 including mixing zone 62, and the fuel injector nozzle components, desirable air-fuel ratios for maximum economy may be realized for engine operating conditions between idling and wide-open throttle operation. The achievement of better mixture distribution in the mixing zone 62 and in mixing passages 19 and 16 permits engine operation at more nearly correct air-fuel ratios instead of the usual somewhat richened mixtures, with gains in fuel economy resulting therefrom. In addition, the provision of air-fuel mixture passages without restrictions therein permits increased air-fuel intake, with resultant gains in horsepower output of the engine.

During engine idling conditions, pressurized fuel is conducted through line 65 to idle jet 74. The correct air-fuel mixture for idling is, of course, easily obtained byadjusting the position of tapered pin 75'. At other than engine-idling conditions, reduced pressures in passage 16 are communicated through opening 171 to the bleeder check valve, which is then forced against wall 70 by spring 170 to close the air opening 171. During acceleration from idle conditions, the idle jet acts as an accelerating jet to quickly deliver increased quantities of fuel in response to opening of throttle valve 17 before the main fuel injector assembly 51 responds. This will occur when fuel pressure regulator 54 delivers increased fuel pressure in response to increased mixture pressure conditions downstream of throttle 17 before diaphragm assembly 41 responds to reduced pressure conditions upstream of the throttle.

Fuel is supplied to both the injection nozzle 51 and the idle jet assembly 66 from the fuel pressure regulator 54, which will be described in connection with Fig. 3. As will be brought out, the action of the regulator is modified in accordance with pressure conditions in the manifold 10 communicated to the regulator by line 86, so that delivered fuel pressure is appropriately raised or lowered to increase the operating efiiciency of the fuel supply system. The solenoid controlled valve 120 between the regulator 54 and T-fitting 55 will be described in connection with Fig. 4.

Referring to Fig. 3 of the drawings, certain modifications in the head assembly 33, diaphragm assembly 41 and injector nozzle 51 are shown in newly numbered detail, while those structural elements remaining the same as in Fig. 1 are given like numerals. The valve 82 in the-bore 57 of the injector nozzle has an upwardly fac-' ing tapered seating surface 83, the latter being urged against an O-ring seat 84 by a compression spring 85 inserted between the valve and a plug 86 threaded into the base of the nozzle. An elongated and tapered pin or pintle 87 projects upward from the valve through an aperture in jet part 188 threaded into the upper end of the nozzle and providing a small orifice to desirably shape and meter the injected fuel charge. The projecting end of pin 87 is engageable by the lower end of a threaded adjusting member 88 carried by plunger 89, which is slidably mounted in a bore 90 in head assembly 33. The lower end of the plunger is rigidly connected to the diaphragm assembly 41, and a compression spring 91 is inserted between the upper end of the injector nozzle 51 and the diaphragm assembly. The diaphragm assembly is urged by the spring toward the dome 38 of the head assembly, but will also tend to be moved in the opposite direction by suction pressure communicated to the mixing zone 62 beneath the diaphragm, chamber 45 between the diaphragm assembly and dome 33 being open to the atmosphere through an appropriate vent therein. In accordance with this arrangement, when the throttle gate 17 is partly or fully opened, suction pressure communicated to the mixing zone 62, causes downward movement of the threaded member 83 into engagement with the pin 87 and subsequent opening of the injector valve. Thus, operation of the modified fuel injection system is substantially the same as that described in connection with Fig. 1. Adjustments in the rate of fuel injection may be secured by loosening a locknut 93 threaded onto the upper end of member 38 so that the latter may be moved in plunger 89 relative to valve pin 87. In this way, opening of the fuel injector valve as a result of movement'of the diaphragm assembly may be changed to secure optimum operation of the injection system.

Quick opening of the injector valve is attained by the provision of additional mechanism located on top of the head assembly 33 as will now be described. The mechanism includes a tubular member 94 attached to a boss 95 formed on the top of the head assembly. The upper end of member 94 is closed to provide a chamber 96 therein which contains a plunger 97 and a spring 98, urging plunger 97 toward the plunger 89 carried in the boss.

communicates withchamber 45 in the head assembly via. passages 99 in the boss, which may be constricted as desired by a valve 100 threaded into the boss. The chamber portion above the plunger 97 communicates with the engine manifold via lines 101 and 80, and fittings 102-, 103 and104, as shown.

Under engine operating conditions corresponding to throttle openings otherthan wide-open, the reduced pressure of the air-fuel mixture in manifold 10 is communicated to chamber 96 and is sutficient to hold plunger 97 in a retracted position in the upper portion of the chamber so that spring 98 is compressed. Should rapid acceleration of the engine be desired, throttle, gate 17 is opened wide, and the resultant increase in pressure of the air-fuel mixture in manifold 10 is communicated to chamber 96 so that the suction on plunger 97 is reduced. As a result, spring 98 forces plunger 97 toward the bottom of chamber 96, displacing air underneath the plunger and thereby effecting downward displacement of diaphragm plunger 89 to quickly open the injector valve 82, allowing a larger quantity of fuel to be injected into the mixing zone. Under these conditions a considerably richened mixture is formed in zone 62 and subsequently conducted to the engine for maximum power operation. Since air in chamber 96 between the two plungers also tends to escape to atmosphere via passages 99, lesser or greater sensitivity of plunger 89 to movement of plunger 97 can be realized by adjustment of constricting valve 100.

As mentioned earlier in this description, pressurized fuel is supplied to the injector nozzle and to the idle jet from a fuel pressure regulator 54, which will now' be described. In the regulator body 105 are positionedtwo diaphragms 106 and 107 extending across separated chambers 108 and 109. The underside of diaphragm 106 communicates with fuel outlet 110 in the body and also with fuel inlet 111 when valve 112 carried by the diaphragm is displaced downward away from valve seat 113. Valve 112 is urged toward seat 113 by a spring 119 therebeneath, and between the valve 112 and the inlet 111 may be included a fuel filter 114, as shown in the drawing. The upper side of diaphragm 106 and the under side of diaphragm 107 communicates with the atmosphere through a vent 115 in the body 105. The upper side of diaphragm 107 communicates with manifold 10 through T-fitting 103 and line 80. A compression spring 116 urges diaphragm 107 toward diaphragm 106, these two members being interconnectedby means of a plunger 117 carried by diaphragm 107 bearing against a compression spring 118 inserted between the upper face of diaphragm 106 and the plunger.

When manifold pressures are considerably reduced below atmospheric pressure, as during idling and small throttle gate openings. suction pressures in the manifold are communicated to the upper side of diaphragm 107, causing. upward displacement thereof against the force of spring 116 with consequent relieving of the pressure on spring 118. Under these conditions, the position of valve 112'is controlled by diaphragm 106 and spring 118 to regulate the pressure of fuel being delivered to the injector nozzle and idle jet.

Increased opening of the throttle gate 17, as during acceleration conditions, effects an increase in manifold pressure, causing a reduction in the pressure differential acrossdiaphragm- 107 and thereby allowing spring 116 to displace diaphragm 107 downwardly to increase the pressure on spring 118. As a result, diaphragm 106 is urged downward to open valve 112, tending to increase the pressure of fuel being delivered to the injector nozzle.

Accordingly, it will be apparent that delivered fuel pressures will be increasedat those times when greater power is demanded from the, engine, corresponding to higher fuel injection rates. As'a result, efiicient'injection; spray" patterns are maintained; in spiteof larger nozzle avenues openings, since delivered. fuel pressure increases asv the nozzle opening increases.

The solenoid controlled valve 120 through which fuel is supplied to the injector is shown in Fig. 4 to comprise a shell 121.containing a solenoid 122 and a valve body 123 at opposite endsther'eof. Inside the body are fuel ontrance and exit passages 1.24 and 125 communicating with one another when neoprene valve 126 is withdrawn from seat 127 in the body. The valve is carried by stem 128 of a plunger 129 which is positioned within a cylindrical aperture 130 in the solenoid. Actuation of the solenoid is conveniently controlled by an automobile ignition switch to effect retraction of the plunger and movement of valve 126 off seat 127 when the switch is closed, allowing pressurized fuel to pass through the valve opening when the engine is running. Upon opening of the switch the solenoid circuit is broken, following which the compression spring131 bearing against the plunger causes closing, of the valve and interruption of fuel flow. Accordingly, when. the engine is not running, fuel cannot leak at the injector nozzle or at the idle jet since valve 126'is closed.

I claim:

1. Apparatus for supplying an air-fuel mixture to an internal combustion engine, comprising means forming an air-fuel mixing passage having an inlet and an outlet at opposite ends thereof, a throttle valve in said passage, an idle fuel jet communicating with said passage at the outlet side of said throttle valve, means forming a chamber extending across and about the inlet end of said first means and opening about said first means to the exterior for flowing air received throughout said chamber opening toward said inlet and at an angle to air how in said passage, said chamber including a zone extending across said inlet and through which air flowing thereto is adapted to change its flow direction, a fuel injector nozzle opening upstream into said zone for injecting pressurized fuel upstream within said zone during non-idling engine operating conditions, and means for delivering pressurized fuel to said jet and to said fuel injecting means.

2. Apparatus for supplying an air-fuel mixture to an internal combustion engine, comprising tubular means forming an air-fuel mixing passage having an inlet and an outlet at opposite ends thereof, a throttle valve in said passage, an idle fuel jet communicating with said passage at the outlet side of said throttle valve, means forming a chamber extending across and annularly about the inlet end of said tubular means and opening annularly about said tubular means to the exterior for flowing air received throughout said chamber opening centrally toward said inlet and at an angle to air flow in said passage, said chamber including a zone extending across said inlet and through which air flowing thereto is adapted to change its flow direction, an annular air filter in said chamber, a fuel injector nozzle opening upstream into said zone for injecting pressurized fuel upstream toward said filter for mixing with filtered inflowing air during non-idling engine operating conditions whereby said filter may receive and suspend unmixed fuel for subsequent entrainment by said inflowing air, and means for delivering pressurized fuel to said jet and to said fuel injecting means.

3. Apparatus for supplying an air-fuel mixture to an internal combustion engine, comprising tubular means forming an air-fuel mixing passage having an inlet and an outlet at opposite ends thereof, a throttle valve in said passage, an idlefuel jet communicating with said passage at the outlet side of said throttle valve, means forming a chamber extending across and about the inlet end of said first means and opening about said first means to the exterior for flowing air received throughout said chamber opening toward said inlet and at an angle to air flow in said passage, said. chamber forming means including a pressure sensitive movable diaphragm spaced 'oppositesaid'inlet and forming a zone extending there across through which air flowing from said chamber to said inlet is adapted to change its flow directionwith reduced velocity in relation to air velocity in said passage, an annular air filter in said chamber, a fuel injector including a nozzle opening into said zone toward the diaphragm and operable in response to diaphragm movement to variably inject pressurized fuel against the diaphrgam and upstream toward said filter for mixing with filtered inflowing air during non-idling engine operating conditions whereby said filter may receive and suspend unmixed fuel for subsequent entrainment by said inflowing air, and means for delivering pressurized fuel to said jet and to said fuel injector.

4. The invention as defined in claim 3 comprising a nozzle orifice and a movable element projecting through said orifice and controlled by said diaphragm for metering fuel flow through said nozzle in accordance with said pressure conditions.

5. The invention as defined in claim 4 comprising means forming a space at the side of said diaphragm opposite said zone and including a conduit connected into said space and into said passage at the inlet side of the throttle for communicating increased suction pressures at the inlet side of said throttle to said space for effecting displacement of said diaphragm and said element in a direction tending to increase the size of said orifice.

6. The invention as defined in claim 4 comprising a nozzle valve movable by said diaphragm to engage a nozzle seat for interrupting fuel flow through said orifice upon exposure of said diaphragm to atmospheric pressure conditions at the inlet sideof said throttle.

7. The invention is defined in claim 4 compnising a conical nozzle opening directed toward said diaphragm to inject fuel in a conically diverging spray pattern upstream into the air flowing through said zone centrally toward said inlet.

8. The invention as defined in claim 6 including a spring urging said valve toward said seat.

9. The invention as defined in claim 4 comprising means responsive to reduce suction pressures at the outlet side of said throttle valve for displacing said diaphragm and said element in a direction tending to increase the size of said orifice.

10. The invention as defined in claim 9 comprising a housing containing a second chamber at the side of said diaphragm opposite said zone, a plunger in said second chamber operatively interconnected with said diaphragm, a spring urging said plunger in a direction tending to effect diaphragm and element displacement to increase the size of said orifice, and means for communicating to said plunger reduced pressures at the outlet side of said throttle to urge said plunger in a spring counteracting direction.

11. The invention as defined in claim 3 in which said last named means comprises a fuel pressure regulator having its discharge directly connected with said jet and fuel injector for receiving pressurized fuel from a fuel pump and delivering fuel to said jet and fuel injector at substantially regulated pressure in response to fuel pressure fluctuations directly communicated from said jet and fuel injector to the regulator.

12. The invention as defined in claim 11 in which said regulator includes a movable regulator valve controlling fuel flow through a valve opening and a pressure regulating diaphragm connected with said valve and exposed to fuel pressure at the outlet side of said regulator valve.

13. The invention as defined in claim 12 including another diaphragm movable in response to changes in air fuel mixture pressures at the outlet side of said throttle and operatively connected with said regulator valve for displacing it to further open said valve opening in response to increased mixture pressures at the outlet side of said throttle.

14. The invention as defined in claim 13 including another spring urging said regulator valve in a-direction to close oif fuel flow through said opening, in response to communication to said other diaphragm of pressure conditions substantially below'atmospheric pressure at the outlet side of said throttle when said throttle is closed.

15. Apparatus for supplying an air-fuel mixture to an internal combustion engine, comprising tubular means forming an air-fuel mixing passage having an inlet diverging in the upstream direction and an outlet at opposite ends thereof, a throttle valve in said passage, anidle jet communicating with said passage at the outlet side of said throttle valve for delivering fuel thereto during engine idling conditions, a shell forming an air-flow chamber extending across and annularly about the inlet end of said tubular means and opening annularly about said tubular means to the exterior for flowing air received throughout said chamber opening centrally toward said inlet and at an angle to air flow in said passage, said chamber including a zone extending across said inlet and through which air flowing thereto is adapted to change its flow direction with reduced velocity in relation to air velocity in said passage, an annular air filter in said shell,

a movable diaphragm mounted opposite said inlet at onev side of said zone for movement toward and away from said inlet in response to air-fuel mixture pressure changes in said zone, a fuel injector nozzll'e opening into said zone toward the diaphragm and operable in response to diaphragm movement to variably inject pressurized fuel against the diaphragm and upstream toward said filter for mixing with filtered inflowing air during non-idling engine operating conditions whereby said filter may receive and suspend unmixed fuel for subsequent entrainment by said inflowing air, said nozzle having an orifice and a movable element directly connected with said diaphragm and projecting through said orifice for metering fuel flow through said nozzle in response to said air-fuel mixture pressure changes, and means for delivering pressurized fuel to said idle jet and to said injector nozzle.

16. The invention as defined in claim 15 including a duct communicating with said passage at the inlet side of the throttle valve and said idle jet during engine idling conditions for conducting air to the pressurized fuel flowing to said jet during idling.

17. The invention as defined in claim 16 including a pressure sensitive valve in said duct adapted to close for preventing said air conduction in response to opening of said throttle valve.

18. The invention as defined in claim 15 in which said means comprises a fuel pressure regulator having its discharge directly connected with said nozzle and idle jet, and a solenoid actuated valve connected in series with said regulator for passing fuel to said nozzle and idle jet only during operation of said engine.

19. Air-fuel supply apparatus for an internal combustion engine, comprising a tube having an upwardly opening inlet and an outlet at opposite ends thereof, a throttle gate in said tube, an air cleaner shell removably mounted on and surrounding said tube in outward spaced relation thereto and containing foraminous material for flowing air to said inlet and filtering the flow through said material in a direction opposite to air flow in said tube, said shell having an upwardly opening end communicating with said inlet, a movable diaphragm extending transversely across and spaced from said open end of the shell and said tube inlet and forming therewith a zone for passing air flowing from said shell reversibly into said tube, a fuel injector nozzle opening directly into said zone toward the diaphragm to variably inject pressurized fuel against the diaphragm and upstream toward said material for mixing with filtered inflowing air Whereby said material may receive unmixed fuel for subsequent entrainment by said inflowing air, and an element carried by said diaphragm and movable within said nozzle for controlling the rate of fuel injection through said 1 1 nozzle in accordance with-'movement of said diaphragm toward and away fromsaid inlet in, response to pressure changes in said zone.

20. The invention asdefined'in claim 19 in which said air cleaner shell has a downwardly opening entrance, and including an outer shell surrounding said air cleaner shell in outward spaced relation thereto and extending below said entrance for flowing air reversibly into said entrance.

21. The invention as defined in claim 20 in which said outer shell contains an. oil bath below said entrance and over which air is adapted to flow reversibly into said entrance.

RefereucesCited in the file' of this patent UNITED. STATES PATENTS 1,407,968 Wickersham Feb. 28, 1922 12 Carter Dec. 24, 1929 Capell Apr. 26, 1932 Beal's Aug. 7, 1934 Weiertz et a1. Sept. 11, 1934 Dore Feb. 7, 1939 Winkler Dec. 28, 1948 Blakeslee July 31, 1951 Winkler et a1 Aug. 28, 1951 Hunt July 1, 1952 Kittler Dec. 8, 1953 Ramsey Dec. 22, 1953 Hunt Mar. 2, 1954 Sebok June 15, 1954 Sebok Jan. 4, 1955

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