US3492981A - Charge forming system for port injection internal combustion engine - Google Patents

Description

Feb. 3, 1970 c. F. HIGH CHARGE FORMING SYSTEM FOR PORT INJECTION INTERNAL COMBUSTION ENGINE 2 Sheets-Sheet l Filed April 29, 1968 BY F162 WL/4,2%: W

Feb. 3, 1970 c. F. HlGH CHARGE FORMING SYSTEM FOR PORT INJECTION INTERNAL COMBUSTION ENGINE 2 Sheets-Sheet 2 Filed April 29, 196s INVENTOR CARL F. HIGH nited States Iatent O 3,492,981 CHARGE FonMrNG SYSTEM FoR PORT INJEC- TioN INTERNAL coMBUsTIoN ENGINE Carl F. High, 17581 Appolne, Detroit, Mich. 48235 Fiied Apr. Z9, 1968, Ser. No. 724,787 Int. Ci. F02m 7/24, 7/00; B01f 3/04 US. Cl. 123-119 9 Claims ABSTRACT F THE DISCLOSURE A charge forming system in which the air induction system has a venturi primary air inlet in parallel with an automatic valve secondary air inlet, which valve moves when actuated by a direct linkage from the main throttle valve of the air induction system at higher engine speeds and operates to open automatically on demand of the engine when same exceeds the capacity of the venturi air inlet to supply sufficient air. The fuel control has two metering orifice valve means in series, the first metering means consisting of a variable opening controlled by a pin which is actuated from a venturi-vacuum controlled diaphragm with an assist at higher engine speeds from a mechanical linkage connected with the automatic air intake valve, and the second metering means, to which fuel is delivered from the first metering means, consists of an axially movable piston having a longitudinal tapered slot registering with the outlet from the first metering means and delivering fuel to uniformly cross-sectional area grooves registering respectively with outlet ports connected to the fuel spray jets disposed at each cylinder intake port-runner, the piston being actuated through a direct mechanical linkage with a manifold pressure operated diaphragm. Improved cylinder intake port construction increases volumetric efficiency, and attitude compensation is also included.

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation-impart of my copending patent application Ser. No. 571,028, filed Aug. 8, 1966 now U.S. Patent No. 3,424,141 of Ian. 28, 196.9.

BACKGROUND OF THE INVENTION This invention relates to charge-forming systems for internal combustion engines using port carburetion in which the air component is inducted through a venturi system and a parallel automatic valve air inlet, which provides secondary air in the upper ranges of engine operation on demand which exceeds the capacity of the Venturi. The present invention has the overall objective of improving and modifying the elements shown in my parent copending application, to give them more positive action and to simplify the manufacture thereof.

SUMMARY OF THE INVENTION The present improvement includes a triple venturi in the venturi air induction portion, with the first fuel control metering orifice valve means being actuated by a diaphragm responsive to vacuum at the smaller venturi for more positive fuel control. The diaphragm is assisted 3,492,981 Patented Feb. 3, 1970 on the piston so that the effective area of the orifice varies as the piston is moved axially, and this metered fuel is then directed to a plurality of uniform cross-sectional area grooves on the piston which respectively register with the outlets to the fuel spray jets. In addition, the piston has a chamber which acts as a fuel accumulator to receive fuel from the tapered metering groove during deceleration of the engine and deliver it through the metering groove during acceleration of the engine. The fuel and air is mixed in the port-runners with improved under, over and down induction of the charge past the valves into the cylinder, producing a generally spherical rotation, with a kinematic-energy of ow build-up of the charge when the intake valve is closed. Crankcase ventilation is provided by inducting air into the crankcase from 'the edge of the air intake of the central venturi, and crankcase fumes are exhausted to the edge of the throttle valve into the air intake manifold. Additionally, altitude compensation is provided through an aneroid valve which spills air into the upper edge of the third or larger venturi, thus reducing the vacuum induced in the restricted portion of the upper venturi to reduce fuel metered by the first metering orifice Valve which is controlled by the vacuum of the upper venturi. The lower and largest venturi receives air from the automatic air inlet when its valve opens.

DESCRIPTION OF THE DRAWINGS A more complete understanding of the present invention will be obtained by reference to the accompanying drawings illustrating a preferred embodiment of the invention in which like reference characters refer to like parts throughout the several views, and in which;

FIG. l is a partially diagrammatic, partially elevational and partially cross-sectional view of the control system, fuel supply system and air induction portion of the engine;

FIG. 2 is a top plan view of the air intake and other devices of FIG. l, with the air cleaner or filter removed for clarity;

FIG. 3 is a cross-sectional view taken substantially on the line 3 3 of FIG. 2, showing the automatic air valve and the fuel metering control system;

FIG. 4 is a cross-sectional view taken substantially on the line 4--4 of FIG. 2, showing the venturi air intake and altitude compensator; and

FIG. 5 is a fragmentary cross-sectional view of a cylinder port runner, fuel spray jet, cylinder intake valve and intake port.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the present improved charge forming system, a housing 10 is mounted on top of an air intake manifold structure (not shown) and has a venturi primary air intake portion 12 as seen in FIG. 4 and a parallel secondary automatic air intake valve portion 14 as seen in FIG. 3, both receiving atmospheric air from an air cleaner or filter (not shown), and delivering a controlled air flow into a throttle passage 16 (FIG. 4), thence to the air intake manifold (not shown) which distributes to the air intake port-runners 18 (FIGS. 1 and 5). The housing 10 also carries the fuel control system shown primarily in FIG. 3, in which fuel is delivered to a first metering valve portion 19, which meters the fuel to a second metering and distributing valve portion 20, from which fuel is directed to port runner fuel spray jet assemblies 22.

The venturi primary air intake portion 12, as seen in FIGS. 2 and 4, comprises an upper inner venturi 26 into which, at the low pressure throat thereof, is disposed a vacuum sensing tube 27 which connects with the first fuel metering portion 19, to be described. The upper inner venturi 26 delivers air into the low pressure throat of a larger central venturi 28, which in turn delivers air into the throat of a lower .outer venturi 30. The venturi 30 delivers air into the throttle chamber 16 which has a conventional butterfly valve 32 mounted on a rotatable shaft 34 supported by the housing 10 and extending exteriorly thereof as seen in FIG. l. A lever 38 secured to the exterior portion on the shaft 34 is connected for throttle operation to an accelerator pedal (not shown) or the like, and is urged toward the throttle valve closed position by an accelerator spring 40 or the like connected at one end to the housing and at the other end with an arm 42 secured to the exterior end of the shaft 34 and extending oppositely from the lever 38.

The secondary automatic air intake valve portion 14 as shown in FIGS. 2 and 4 comprises an air intake passage 44 provided in the housing 10, for delivering air when the engine operates at the higher throttle ranges when engine demand exceeds the capacity of the triple venturi Iportion 12. The passage 44 is normally closed during the lower throttle ranges by a valve 46 mounted on a shaft 48 which extends exteriorly of the housing 10 and parallel with the throttle shaft 34. As seen in FIG. l, a spring 50 connects the lever arm 42 of the throttle shaft 34 `with an arm 52 securedto the exterior end of the automatic air valve shaft 48 to normally hold the automatic air valve 46 in the closed position during part throttle .operation of the engine. As the throttle lever 38 is moved toward the throttle open7 position, the tension on the spring 50 will be relaxed to a point at which the spring, which has enclosed within its coils a rod 54, becomes a solid connecting link between the throttle shaft arm 42 and the air valve ar-m 52. Complete opening of the air throttle 32 will, through the tension-spring 50 and rod link 54, rotate the shaft 48 of the air valve 46 to a position at which the valve, having closely-fitted sides 46A and end 46B will move downwardly into a wider and longer open space below a shoulder 55 which intersects the valve shaft 48 for correctly proportioned air lio-w through side openings 46C. At other settings, when the demands of the engine for air increases beyond that which can be supplied by the venturis, the valve 46 will open against the restraint of the spring 50 to admit air into the chamber 44 and thence into the large lower venturi 30.

Fuel for the engine is supplied from a sealed fuel tank 60 by a supply pump 62 through a conduit 64 to a fuel inlet 66 in the housing 10 to a chamber 68 (FIG. 3), this chamber being kept at all times filled with fuel under supply-pump pressure to the height .of a bleed orifice 69 from whence it is returned by a conduit 83 (FIG. 1) to the sealed fuel tank 60. Venting of the tank 60 may be through the fuel return conduit 83 by means of a port 82 from the chamber 80 or through a separate vent line, the final venting to atmosphere being through a tube 81 which continues to the highest point in the air filter (not shown) As further shown in FIG. 3 first fuel metering means 19 comprises an orifice 70 variably opened and closed by a needle valve pin 72 which is carried and operated by a diaphragm assembly 74 which constitutes one wall of a vacuum chamber 76 openly connected with venturi vacuum through the conduit 27. The diaphragm and the needle valve pin 72 are urged towards the valve closed position by a spring 78 against which the vacuum forces from the venturi are balanced. The chamber 80 on the opposite side of the diaphragm 74 is openly connected with atmosphere through the vent tube 81 to provide vacuum-atmosphere differential across the diaphragm 74. A port 82A .open to the fuel chamber 68 bleeds any leakage fuel collected in the chamber 80 back to the fuel tank 60 through the conduit 83.

As seen in FIG. l, a lever arm 84 is secured to the exterior end of the air valve shaft 48 and is operably connected by means 0f a link 86, which has a spring-loaded vvlength adjusting thumb screw 87, with a lever arm 88 secured to the exterior end of a shaft 90 extending into the chamber 80 to a lever 92 disposed beneath the diaphragm assembly 74 as shown in FIG. 3. In operation, when the air valve 46 is moved toward the open position, the aforesaid linkages actuate the lever 92 upward against the diaphragm assembly 74 to assist in .overcoming the resistance of the spring 78 to move the needle valve pin 72 toward the open position, supplying additional fuel from the fuel chamber 68 through the orifice 70. This raising of the metering valve pin 72 in its `orice 70 will supply the fuel needed to burn with the proportioned mass of air which is being inducted by the engine.

It is significant to note that not only can the contour of the fuel-metering valve pin 72, which is raised .or lowered in the orifice 70, be tapered or formed on its sides to supply the correct quantity of fuel to burn with the air inducted, the air valve 46 also, by modification of the contour of its shielded sides 46A and 46B, or by providing the openings 46C of various areas through any or all of the three shielded sides, which open into the enlarged space below the shoulder 5S to flow air to the lower or main venturi 30, can be calibrated to flow the exact amount of air to match the ideal fuel in that range of engine operation. A fuel-air curve once worked out with this accuracy can be duplicated indefinitely by simply maintaining dimensions within approved tolerances of the fuel metering and the air metering components.

The second metering portion 20 comprises a piston 94 axially movable within a cylindrical sleeve 96 secured in the housing 10 as shown in FIG. 3. The piston 94 has a single longitudinally extending tapered groove oriice 98 disposed in registry with a fuel outlet port 100 connected with the orice 70. The piston 94 is actuated through a link 102 fulcrumed on a pin 104 and pivotally connected with an arm 106 mounted on a diaphragm assembly 108 which forms one wall of a manifold pressure chamber 110, openly :connected by any means (not shown) with the throttle valve passage 16 downstream of the throttle valve 32, thereby providing engine manifold pressure to the chamber 110. The other side of the diaphragm assembly 108 is subject to filtered air pressure admitted to chamber 109 through air inlet ports 111 shown in FIG. 2 to provide manifold-atmosphere differential across the diaphragm 108. The diaphragm assembly 108 is urged by a spring 112 toward a position actuating the piston 94 to the left, as shown, toward its full open position (that is, with the larger end of the tapered groove 98 orifice being registered with the port 100). With the lower manifold pressures produced at the lower ranges of engine operation, manifold suction tends to retract the diaphragm assembly 108 and move the piston 94 to the right toward a position where a smaller crosssectional area of the longitudinal tapered groove orifice 98 registers with the port 100, thereby decreasing fuel ow into the groove 98 which communicates with an annular groove 114 on the piston 94. A plurality of longitudinal uniform cross-sectional area grooves 116 provided on the piston 94 are open to the annular groove 114 and respectively register with outlet passages 118 connected with conduits 120 only (one of each is shown in FIGS. l and 3 respectively).

The conduits 120 deliver fuel to fuel spray jets 122 provided at each cylinder intake port runner 18 to spray the fuel into the air inducted to the cylinder intake valve port chamber 24 which is constructed to produce a continuous swirl for thorough air and fuel`rnixing before the charge is admitted on the intake stroke of the engine piston 123 when the intake valve 124 is open. As seen in FIGS. 1 and 5, the intake valve port chamber 24 is axially offset from and elongated beyond the intake valve proper, and is semi-spherically contoured, so as to produce an induction of the fuel-air charge as indicated by the liow lines, under, over and down past the valve 124 when open into the engine cylinder. When the intake valve S 124 is closed, the present construction of the chamber 24 produces a generally spherical rotation of the charge with a kinematic-energy of ow build-up of the charge during the three piston strokes when the valve 124 is closed.

The fuel metering piston 94 performs an additional function during acceleration and deceleration. Between the outer end of the piston and the closed end of the sleeve 96 there is provided an accumulator chamber 125 open to the smaller end of the tapered groove 98. O11 deceleration, when the piston 94 moves to the right, fuel ows into the chamber 125 from the groove 98, thereby assisting to decrease flow to the fuel spray jets. On acceleration, when the piston 94 moves to the left, the accumulated fuel is forced out into the groove 98 from the chamber 125 to assist in increasing fuel flow to the spray jets.

Operation of the diaphragm 108, and hence the metering piston 94, operates to modify fuel delivered from the air venturi vacuum-actuated metering valve orilice 70 to compensate for variations f manifold pressure produced under varying engine operating conditions to provide proper ratios of fuel to inducted air at all times.

Altitude compensation in the present engine is provided as shown in FIG. 4 by an aneroid 126 disposed in an air chamber 128 open to filtered air through an air port 130. The aneroid 126 is provided on one end with a valve disc 132 arranged to admit air into the upper edge of the lower outer venturi 30 when the aneroid 126 expands with an increase in altitude, thus reducing or modifying the induction of air through the upper inner venturi 26. This reduces or modifies the vacuum sensed in the first metering valve diaphragm chamber 76, thus tending to cause the needle valve 72 to move toward its closed position, decreasing fuel iiow to the engine. Adjustment is provided by a screw 131, with a compressible Washer 133 disposed on the end of the aneroid 126 opposite the valve disc 132.

A ram air inlet 56, seen in FIGS. 2 and 4 is provided adjacent (to and arcuately subtending) about 120 of the upper edge of the intermediate venturi 28 to provide ram air pressure for purging the crankcase (not shown) through appropriate passages thereto.

Crankcase fumes from the engine are admitted through other appropriate passages connected to the crankcase, to the edge of the throttle valve 32 from a terminal chamber 134, which is provided with adhesion plates 136 to collect gums, resins and other solids passing out of the crankcase. The element including the adhesion plates 136 may be readily removed from the side of the housing for cleaning.

It is noted that air supplied to the engine air induction system, to the operative chamber 76 of the first metering valve diaphragm 74, to the atmospheric side of the manifold pressure diaphragm 108, and to the aneroid chamber 128, comes from the downstream side of the air cleaner or iilter (not shown), so that even as air ow is decreased -by cleaner or filter clogging, hence reducing its pressure to sub-atmospheric, these devices will be operably sensitive to the same parameters, maintaining correctly balanced fuel and air ows at all times.

The primary improvements of the present invention as heretofore described, but not necessarily in order of importance, therefore consist of:

(A) Fuel and air charge-mixing, in which the port chamber 24 produces under, over and down induction of the charge past the open intake valve 124 into the engine cylinder, with a generally spherical rotation and kinematic-energy of ow build-up of the charge during the three strokes of the engine piston while the intake valve is closed.

(B) Crankcase ventilation, in which the ram air inlet 56 is disposed adjacent to an arcuately subtending 120 of the edge of the air intake of the intermediate or central venturi 28 and the entrance for fumes from the crankcase is past 136 provided throttle disc 32 into the induction system of the engine, with the adhesion plates 136 by which are removed the gums, resins and other solid particles which are drawn with the fumes from the engine crankcase.

(C) Altitude compensation, in which the aneroid 126 operates to spill air as altitude is gained into the upper edge of the lower venturi 30, which spilled air will delay or modify the air inducted through the boost veuturis, reducing the vacuum induced in the throat of the upper venturi 26 and thereby reducing the fuel metered by the first metering control.

(D) Improved fuel metering, in which the second metering means piston 94 requires only one tapered metering groove 98, and which provides a fuel accumulator chamber 125 at the end of the piston 94.

(E) The triple venturi system which extends the metering range and produces more positive control.

In operation, with the throttle 32 held closed by the laccelerator spring 40, the engine may be started on idling fuel and air setting. If the engine has been out of service for some time, or if it is extremely cold, priming fuel may be supplied directly to the intake ports by depressing the accelerator pedal (not shown) to nearly a full throttle opening. With fuel in the fuel chamber 68, this opening of the throttle valve 32, through the linkage provided, causes the shaft to be rotated and the lift arm 92 secured to the shaft 90 operated to raise the metering needle pin 72 and permit fuel to be delivered to the intake ports of the engine. Should the engine be overprimed, an approximately one-half opening of the air throttle 32 will make possible the scavenging of the Overrichness by cranking the engine with the starter.

With the engine started and running the small boost venturi 26 will operate to evacuate the chamber 76 sufficiently to start raising the metering needle pin 72 and supply fuel to burn the air inducted through the venturis. With nearly full opening of the throttle, the automatic air valve 46 will admit additional air and the main venturi 30 comes into action to further boost the air flow through the smaller venturis. Closely following the raising of the metering needle pin 72 by the venturi-created vacuum, is the accelerator-connected lift-arm 92 on the metering shaft 90. Should the throttle 32 be suddenly opened by full depression of the accelerator pedal, the lift-arm 92 may precede the vacuum lift of the metering needle pin 72. Depending upon the setting of the adjustable linkage 86, by turning of the thumb screw 87, the lead time of the vacuum lifted pin 72 can be reduced and the fuel for acceleration thereby increased. With the adjustment of the link 86, the automatic opening of the air valve against the tension of the link spring 50 is also changed. The balance of these features is provided in their construction and only initial adjustment is anticipated.

Although I have described only one embodiment of my invention, it Will be apparent to those skilled in the art to which the invention pertains that various changes and modifications may be made therein without departing from the spirit of the invention as expressed by the scope of the appended claims.

I claim:

1. In an internal combustion engine port carburetion fuel and air charge forming system, in which the fuel component of said charge is produced by operation of two series-connected orifice means, a housing having a iirst Vorifice means comprising an air intake venturi-suction actuated valve delivering fuel to a second orifice means, Said second orifice means comprising (a) a piston axially movable within said housing and operably connected with means responsive to manifold pressure variations,

(b) said piston having a longitudinally tapered groove orifice on its outer surface disposed for longitudinal registry with an outlet port openly connected with said irst orifice means,

(c) a plurality of longtitudinal uniformly equal crosssectional area grooves on the outer surface of said piston and located in registry respectively with outlet ports adapted for respective connection with fuel spray jets at engine port-runners, and

(d) means openly connecting said equal cross-sectional area grooves with the larger end of said tapered groove orice whereby axial movement of said piston produces uniformly varied delivery of fuel to said fuel spray jets.

2. The system as defined in claim 1 and in which (a) said piston is movable within a sleeve which has a closed end to form between it and an end of said piston an accumulator chamber,

(b) the smaller end of said tapered groove orice being open to said accumulator chamber, whereby said `accumulator chamber receives fuel from the tapered groove orifice when the piston moves away from said sleeve end on engine deceleration and discharges fuel into said tapered groove orifice when the piston moves toward said sleeve end on engine acceleration.

3. In an internal combustion engine port carburetion fuel and air charge forming system having an air throttle valve, in which the air component of said charge is produced upstream of said throttle valve by admission of primary air through a venturi means and by admission of secondary air through 4an automatic air valve during higher speed and operation above part throttle operation, the improvement comprising (a) said venturi means including a plurality of venturis with smaller venturis delivering air to the lowpressure throats of successive larger venturis,

(b) said automatic air valve delivering air into the larger venturi upon actuation by the throttle and automatically upon engine demand exceeding the capacities of the smaller vcnturis.

4. The improvement as defined in claim 3 and includf ing fuel control means comprising (a) a rst orifice metering valve operably connected for actuation in response to variations of vacuum produced at the low pressure throat of the smallest of said venturis, and for actuation mechanically in response to movement of said automatic air valve and selected portions of throttle operation.

5. The improvement as defined in claim 4 land includmg an altitude compensating means comprising means opening a larger venturi to atmosphere variably as atmospheric pressure decreases, whereby to reduce the vacuum effect of said smallest venturi on said rst orifice metering valve.

6. The improvement as dened in claim 5 and in which said altitude compensating means comprises (a) a chamber open to atmosphere,

(b) a valve variable openly connecting said chamber to the upstream end of said larger venturi,

(C) an aneroid in said chamber and 'operably connected with said valve to variably open same as atmospheric pressure decreases.

7. The improvement as dened in claim 3 and including means adapted to deliver ram air to the engine crankcase for ventilation thereof, said means conprising an air inlet opening adjacent to and arcuately subtending about 120 of the upstream end of one of said venturis,

8. The improvement as defined in claim '7 and including means adapted to exhaust blow-by gases from the engine crankcase, said means comprising a passage having an opening adjacent to and upstream of the engine throttle valve, and said throttle valve being constructed and arranged to substantially close said opening when said throttle valve is closed.

9. In an internal combustion air induction system, the improvement comprising (a) a plurality of air induction venturis of progressively larger sizes, the smaller venturis inducting air into the low pressure throat of successively larger venturis,

(b) fuel control means connected with and sensing pressure at the throat of other than a larger venturi,

(c) altitude compensating means operable to variably admit air independently to said larger venturi to modify the air inducted through the smaller venturi to which said fuel control means is sensitive and hence modify operation thereof.

References Cited UNITED STATES PATENTS 2,893,711 7/1959 McDue 261-23.1 3,424,141 1/1969 High 12S-119 3,425,672 2/1969 Seige et al. 261-23.1

FOREIGN PATENTS 833,178 4/1960 Great Britain.

WENDELL E. BURNS, Primary Examiner U.S. Cl. X.R. 261-23, 50

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