US2882879A

US2882879A - Fuel injection systems

Info

Publication number: US2882879A
Application number: US713578A
Authority: US
Inventors: Dolza John
Original assignee: Individual
Current assignee: Individual
Priority date: 1958-02-06
Filing date: 1958-02-06
Publication date: 1959-04-21
Anticipated expiration: 1976-04-21

Description

A ril 21, 959 J. DOLZA 2,882,879

FUEL INJECTION SYSTEMS Filed Feb. 6, 1958 Am WW INVENTOK Jxl/v 30L Z4 Unite This invention relates to improvements in fuel injection systems of the type in which fuel is distributed uniformly to the cylinders of a multi-cylinder internal combustion engine.

In the presently conventional carburetor and intake manifold system of multi-cylinder gasoline engines employing a spark ignition system, a considerable amount of heat is applied to the fuel-air mixture provided by the carburetor to produce a reasonably uniform dispersion of the fuel and air of the mixture to obtain a relatively satisfactory degree of engine performance.

The heat necessary to produce a relatively uniform fuel distribution in a spark-ignited gasoline engine of a given design at a reasonable fuel consumption causes secondary harmful effects upon the engine such as a loss of otherwise attainable power output due to a reduced air density, requiring the use of gasoline of higher octane rating, increasing engine cooling requirements, increasing the in- .Cidence of vapor lock in the carburetor, and a loss of fuel due to evaporation at the carburetor.

As a result of the foregoing, carburetted engines generally incorporate in their designs a compromise between uniformity in fuel distribution and heat applied to the mixture in the intake manifold system.

In carburetted engines, most of the fuel is carried through the intake manifold system in the form of droplets of various sizes suspended in the manifold air stream. Some of these fuel droplets collect in the manifold and flow along the bottom thereof to the cylinders. The fuel deposited in the intake manifold system is caused to flow from the carburetor to the cylinder intake ports by properly sloping the manifold system from the carburetor down to the engine intake ports and by the aerodynamic action of the air-fuel mixture passing therethrough.

In vehicular engines, the slope of the intake manifold system cannot be relied upon as the only factor in carrying liquid fuel deposits therein to the intake ports of the engine inasmuch as during the operation of the vehicle both the longitudinal and the transverse manifold system passages change their normal attitudes according to the terrain over which the vehicle is being driven, and because the vehicle is subjected to various accelerations and decelerations.

To obtain an adequate aerodynamic force on the liquid fuel deposits in the manifold system of carburetted internal combustion engines to constantly move the said fuel deposits through the manifold system to the engine cylinders and to assure delivery of a proper air-fuel mixture at the said cylinders, it is presently necessary to use a high manifold air-fuel mixture velocity throughout the manifold system, and to accept the resulting undesirable pressure drop in the intake manifold and its corresponding reduction in power delivered by the engine.

Furthermore, a manifold system carrying a mixture of air and fuel is subject to varying degrees of fuel wetness,

which for example, ranges between a dry manifold occa- States Patent sioned when high vacuum occurs in the manifold system i 2 2,882,879 Patented Apr.- .21, 1959 and a wet manifold occasioned when a low vacuumexists therein. This condition requires the use of an accelerat ing pump which provides a shot of fuel in the manifold system when changing from a high vacuum to a low vacuum during engine acceleration or in response to increased engine load, thus supplying the wetness in the manifold system and also overcoming the inertia of the normal fuel flow therein against following a rapid increase in the rate of air flow through the said manifold system.

With the foregoing in view, the primary object of this invention is to eliminate or reduce to a minimum the aforementioned inherent shortcomings of carburetted engines by the employment in lieu of the conventional carburetor a simple and relatively inexpensive mechanical fuel injection system which is not only highly etficient and effective under varying engine operating conditions, but which may be easily and readily maintained.

Other objects of the invention will become apparent by reference to the accompanying drawing, in which:

Fig. 1 is a more or less diagrammatic view of a injection system embodying the invention.

Fig. 2 is a diagrammatic view of a portion of the fuel injection system disclosed in Fig. 1 showing an alternate arrangement of the fuel enrichment means employable upon acceleration of the engine.

Referring now to the drawing wherein like numerals refer to like and corresponding parts throughout the several views, the fuel injection system embodying the invention shown more or less diagrammatically in (Fig. 1 is employed in conjunction with a conventional internal combustion engine including an intake manifold system generally designated by the numeral 10 having an air intake 11 controlled by a butterfly type throttle valve 12 and distribution manifolds 13 communicating with the intake valves 14 of all engine cylinders 15 into which pistons 16 are reciprocatingly mounted. A venturi 17 is interposed in the air intake 11 and is surrounded by an air chamber 20 closed in respect to ambient air. The throat of the venturi 17 is transversely slotted or perforated at to provide communication between the said venturi throat and the said closed air chamber 20 creating therein a negative pressure which varies according to the air intake of the engine cylinders.

An engine operated fuel delivery suction type gear pump 21 is enclosed within the closed air chamber 20 and 'is provided with an enlarged open inlet 22 disposed within the said closed air chamber 20. A fuel chamber 23 vented to atmosphere at 24 is preferably located adjacent the said closed air chamber 20. Fuel is supplied by the main engine fuel pump P to the said fuel chamber 23 through a fuel line 25 which may be closed by a float valve 26 to prevent the filling of the fuel chamber '23 above a predetermined level. A fuel line 27 extends from the bottom of the fuel chamber 23 to the air chain 'ber 20 where it is nozzled into the said open inlet 22 of the fuel delivery pump 21. A metered amount of fuel is withdrawn from the fuel chamber 23 through the fuel line 27 to the open inlet 22 of the fuel delivery pump 21 by a variable negative pressure created in the closed air chamber 20 by the air intake through the venturi 17 to the engine cylinders 15 when the engine is being started or running. The fuel delivery pump 21 is preferably engine driven in a proportion to engine speed so that it has a displacement somewhat greater than the engine fuel requirement. Therefore, the fuel metered :to-the engine cylinders through the venturi controlled vacuum fuel metering system as herein disclosed pick p a small volume of air as it passes through the enlarged open inlet 22 of the fuel metering pump 21, but not an amountsufli. vcient to adversely affect the metering of fuel by th my, mal venturi action of .thesaid fuel metering system.

Thusly, a mixture of fuel and a small amount of air is fuel forced by the fuel delivery pump 21 to a distribution chamber 30 located at the discharge end of the said fuel delivery pump 21, the said fuel distribution chamber 30 extending in sealed relationshipthrough the bottom of. the closed air chamber 20. The said fuel and air mixture is forced under pressure by the fuel delivery pump 21 from the said distribution chamber 30 through distribution fuel lines 31 to and through low pressure fuel nozzles 32 extending within the engine air intake distribution manifolds 13 adjacent the intake valves 14. Thusly the said fuel and air mixture is injected into the intake manifold air stream at the engine intake valve 14 at each engine cylinder 15 from whence it is drawn into the said engine cylinders 15 during the suction stroke of the pistons 16 reciprocating therein.

' The fuel delivery gear pump 21 insures the proper flow of fuel together with a small percentage of the total air required by the engine to support combustion under all engine throttle conditions regardless of the fact that the pressure at the open ends of the fuel nozzles 32 at times may be higher than in the closed air chamber 20.

With the foregoing fuel system wherein a venturi metered fuel supply mixed with a small amount of air is delivered under moderately low pressure directly to the intake manifold air stream at each cylinder, it is possible to carry fuel at equal rates to all intake valves with relatively inexpensive low pressure fuel lines and fuel nozzles, and with practically no sensitivity to normal acceleration or normal attitudes assumed by the engine during the operation of a vehicle equipped therewith. Furthermore, since only air supplied to the engine cylinders passes through the intake manifold system controlled by the throttle valve 12, no restriction to air flow to the engine cylinders will be required to increase air velocity therein for the purpose of assuring proper fuel distribution, and the heating of the manifold, although desirable in instances where fuel of a relatively low volatility is employed, is not essential. However, when the throttle 12 is opened abruptly while the engine is in operation, the air flow to the cylinders through the manifold system increases faster than the flow of fuel from the venturi controlled fuel metering system and the fuel delivery pump 21 through nozzles 32 to the manifold at the intake valves 14 of the engine cylinders 15.

To overcome this temporary fuel deficiency, a shot of fuel may be delivered to the distribution chamber 30 through an auxiliary fuel line 34 by an acceleration pump 35 disposed in the fuel chamber 23 below the normal level to which fuel is maintained therein. The said acceleration pump 35 is preferably operated by the accelebrator pedal of an automotive vehicle through a suitable linkage, not shown. As illustrated, the accelerator pump may consist of a cylinder 36 into which is mounted a piston 37 actuated through its piston rod 370 by depressing the vehicle accelerator pedal. The said piston 37 preferably has a relief orifice 371 therethrough of a size to permit normal accelerator pedal depression without delivery of extra fuel to the fuel distribution chamber 30. A spring loaded check valve 38 at the discharge end of the cylinder 36 maintains the cylinder 36 filled with fuel except when the piston 37 is actuated. A check valve 39 in the top of piston 37 permits the cylinder to be filled on its return stroke. The shot of fuel delivered by the acceleration pump 35 responsive to rapid opening of the throttle valve 12 by rapid depression of the engine accelerator pedal produces a temporary enrichment of the fuel-air mixture being supplied to the engine cylinders 16 at their intake valves 14 through the fuel distribution lines 31 and low pressure fuel nozzles 32 while the required new increased rate of fuel flow is being established by the venturi controlled fuel metering system. Obviously, other means for overcoming this fuel deficiency may be employed; for example, a shot of fuel may be delivered from the acceleration pump 35 to the open inlet 22 of the fuel delivery pump 21 through an auxiliary fuel line 270 from the acceleration pump 35, see Fig. 2.

In the embodiment of the invention disclosed in Fig. 1, an engine idle enrichment of the fuel-air mix at the engine cylinders is accomplished by connecting idle signal orifices 40 in the manifold section in which the throttle valve 12 is located to the air chamber 20 by means of an idle air passage 41. The said idle signal orifices are located slightly below the throttle valve 12 when in its substantially or idle closed position as indicated by the dot and dash lines in Fig. 1. An idle air by-pass 42 is provided around the throttle valve 12, and the amount of idle air by-pass is regulated by a needle valve 43. At low engine throttle, the foregoing construction provides a relatively high volume of fuel transfer to the fuel delivery pump 21 at relatively low engine speeds.

By progressively closing an air valve 44, according to decreases in engine starting temperatures, which air valve 44 located in a shroud 1700 disposed around the throat of the venturi 17 restricts the flow of air through the port 45 to the slotted orifice in the throat of the said venturi 17, a greater suction or increased negative pressure will occur in the air chamber 20, with the result that a greater fuel enrichment is provided for cold engine starting equivalent to the fuel enrichment normally obtained by the carburetor choke of a carburetted engine. The air valve 44 has its operating arm 46 fulcrumed at 47, and the free end of the said operating arm 46 is pivotally connected to the movable arm 480 of a thermostat 48 which is fixedly mounted at 49.

A suitable variable fuel orifice such as a needle valve 50 under control of suitable air density sensor means is preferably provided in the fuel passage or fuel line 27 extending from the bottom of the fuel chamber 23 to the air chamber 20 wherein the fuel is nozzled into the open inlet of the engine driven fuel delivery pump 21. The variable fuel orifice 50 or other suitable means may be employed to modify the rate of fuel flow to the fuel delivery pump 21 in relation to any given negative pressure created in the air chamber 20 by the venturi 17 of the air intake 11 to the engine manifold system 10 and the cylinders 15.

An air density sensor means for controlling a variable fuel orifice such as the orifice of the needle valve 50 may lnclude an aneroid 51 having a diaphragm movable responsive to changes in external air pressure fixedly supported at 52 and pivotally connected by an arm 53 to one end of a floating lever 54. The other end of the floating lever 54 is connected by an arm 55 to a thermostatic element 56 fixedly supported at one end at 57, the said thermostatic element 56 being movable responsive to changes in ambient air temperature. The needle valve 50 is operatively connected by an arm 58 to one end of a needle valve operating lever 59 fulcrumed at 60 to a fixed point 70, which lever opens and restricts the flow of fuel through the needle valve 50. The other end of the said lever 59 is pivotally connected by a link 61 to a fulcrum 62 to which is pivotally connected to the central portion of a floating lever 63. One end of the said floating lever 63 is pivotally connected by a link 64 to the said floating lever 54 between the outer ends thereof. The other end of the floating lever 63 is pivotally connected by an arm 65 to the spring loaded diaphragm 660 of an air chamber 66 which is fixedly supported at 67. The said air chamber 66 is connected by a line 68 to the engine intake manifold system 10 so that the said diaphragm 660 of the air chamber 66 is movable responsive to variations in the negative pressure in the engine intake manifold system 10 when the engine is running.

By use of such an air density and manifold pressure sensing means as above described, the collapsing of the aneroid 61 responsive to an increase in ambient atmcs pheric pressure, and/or movement of the thermostatic element 56 responsive to a lowering of ambient air temperature, and/or the movement of the diaphragm 660 of the air chamber 66 responsive to an increase in the pressure in the manifold system 10 will open the variable fuel orifice of the needle valve 50 and allow the passage of a greater amount of fuel from the fuel chamber 23 to the enlarged open inlet 22 of the fuel delivery suction gear pump 21 in the air chamber 20 for any given amount of negative pressure established in the said air chamber 20 by the suction of air to the engine cylinders by its piston 16 through the venturi 17 and the engine intake manifold system 10.

A suitable device 700 at the fixed pivot point 70 of the fulcrum 60 for sensing the closing of the engine throttle in combination with deceleration of the vehicle may be employed to move the otherwise fixed fulcrum 60 of the needle valve operating lever 59 to close or substantially close the orifice of the needle valve 50, thus preventing the use of fuel by the engine during deceleration of the vehicle and decreasing air pollution normally caused by incomplete or improper combustion of fuel which otherwise would be drawn into the engine cylinders. Obviously, other fuel flow regulating means may be employed to control the rate of flow of engine fuel for any given demand therefor established by negative air pressure created in the air chamber 20 by the venturi 17 in the air intake 11 to the engine intake manifold system 10.

Although but one specific embodiment of the invention and a single modification thereof have been disclosed and described herein, it is obvious that many changes may be made in the size, shape, arrangement and detail of the various elements of the invention, and that the method steps employed in carrying out the invention may be modified, all Without departing from the spirit and scope of the invention as defined by the appended claims.

I claim:

1. In a fuel injection system for internal combustion engines including an intake manifold system communicating with the intake ports of the engine cylinders, an air inlet to the intake manifold system including a venturi, a closed air chamber communicating with the throat of said venturi, an engine operated fuel delivery pump in said air chamber including an open inlet thereto within said air chamber, a fuel chamber including a fuel inlet thereto from the engine fuel pump and a fuel line therefrom to said fuel delivery pump discharging fuel into said open inlet to said fuel delivery pump in metered amounts responsive to negative pressure created by said venturi in said closed air chamber, the said fuel delivery pump being driven by the engine proportionate to engine speed and having a displacement somewhat greater than the engine fuel requirement whereby to furnish a mixture of fuel and air through said fuel delivery pump, a distributor well into which said fuel delivery pump discharges, and means communicating with said distributor well distributing said fuel air mixture uniformly to said cylinders at the intake valves thereof in the presence of air drawn into said cylinders through said intake manifold system and the air inlet thereto.

2. In a fuel injection system for internal combustion engines including an air intake manifold system communicating with intake ports of each of the engine cylinders, an air inlet to said manifold system including a venturi therein, a fuel chamber, pump means delivering fuel to said engine, venturi suction means for metering fuel from said fuel chamber to said delivery pump responsive to negative pressure at said venturi, and means uniformly distributing fuel from said fuel delivery pump to said intake manifold system at the intake port of each engine cylinder.

3. In a fuel injection system for internal combustion engines including an air intake manifold system communicating with intake ports of each of the engine cylinders, an air inlet to said manifold system including a venturi therein, a fuel chamber, fuel delivery pump means delivering fuel to said engine, and venturi suction means for transferring fuel from said fuel chamber to said fuel delivery pump metering said fuel transfer responsive to negative pressure at said venturi, means uniformly distributing fuel from said fuel delivery pump to said intake manifold system at the intake port of each engine cylinder, and means regulating the flow of fuel from said fuel chamber to said delivery pump responsive to changes in atmospheric pressure, atmospheric temperature and negative manifold pressure.

4. In a fuel injection system for internal combustion engines including an air intake manifold system communicating with intake ports of each of the engine cylinders, an air inlet to said manifold system including a venturi therein, a fuel chamber into which a small quantity of fuel is constantly maintained at a given level, a fuel delivery pump driven proportionate to engine speeds for delivering fuel to said intake manifold system at the intake port of each cylinder, and means supplying fuel from said fuel chamber to said fuel delivery pump responsive and according to the negative pressure established by air passing through said venturi to said cylin- .ders.

5. In a fuel injection system for internal combustion engines including an air intake manifold system communicating with intake ports of each of the engine cylinders, an air inlet to said manifold system including a venturi therein, a fuel chamber into which a small quantity of fuel is constantly maintained at a given level, a fuel delivery pump driven proportionate to engine speeds for delivering fuel to said intake manifold system at the intake port of each cylinder, means supplying fuel from said fuel chamber to said fuel delivery pump responsive and according to the negative pressure established by air passing through said venturi to said cylinders, and means regulating the flow of fuel from said fuel chamber to said delivery pump responsive to changes in atmospheric pressure, atmospheric temperature and negative manifold pressure.

6. In a fuel injection system for internal combustion engines including an intake manifold system communicating with the intake ports of the engine cylinders, an air inlet to the intake manifold system including a venturi, a closed air chamber communicating with the throat of said venturi, an engine operated fuel delivery pump in said air chamber including an open inlet thereto within said air chamber, a fuel chamber including a fuel inlet thereto from the engine fuel pump and a fuel line therefrom to said fuel delivery pump for discharging fuel into said open inlet to said fuel delivery pump in metered amounts responsive to negative pressure created by said venturi in said closed air chamber, the said fuel delivery pump being driven by the engine proportionate to engine speed and having a displacement somewhat greater than the engine fuel requirement whereby to furnish a mixture of fuel and air through said fuel delivery pump, a distributor well into which said fuel delivery pump discharges, means communicating with said distributor well uniformly distributing said fuel-air mixture to said cylinders at the intake valves thereof in the presence of air drawn into said cylinders through said intake manifold system and the air inlet thereto, variable orifice means in the fuel line from said fuel chamber to said fuel delivery pump, and aneroid means, thermostatic means and manifold pressure responsive means interconnected With each other and said variable orifice means for regulating said variable orifice means to vary the flow of fuel from said fuel chamber responsive to changes in atmospheric density and manifold pressure.

7. In a fuel injection system for internal combustion engines including an intake manifold system communicating with the intake ports of the engine cylinders, an air inlet to the intake manifold system including a venturi,

an engine throttle valve in said manifold system controlling the passage of air therethrough, a closed air chamber communicating with the throat of said venturi, a fuel chamber including a fuel inlet from a fuel source, fuel delivery pump means including an open fuel inlet thereto located in said closed air chamber, a fuel line from said fuel chamber to said open fuel inlet of said fuel delivery pump through which a metered amount of fuel from said fuel chamber is transferred and discharged into said fuel delivery pump inlet, said fuel transfer being accomplished responsive to negative pressure created by said venturi in said closed air chamber, the said fuel delivery pump being engine driven proportionate to engine speed, and means uniformly distributing fuel from said fuel delivery pump to said cylinders at the intake valves thereof in the presence of air drawn into said cylinders through said intake manifold system.

8. A fuel injection system as claimed in claim 7 where in the fuel delivery pump has a capacity greater than the engine fuel requirement whereby to cause the entrainment of air from said air chamber in said fuel delivery means to said intake valves.

9. A fuel injection system as claimed in claim 7 including means regulating the flow of fuel from said fuel chamber responsive to ambient air pressure, ambient air temperature and negative pressure in the manifold system of said engine independent of the said venturi created negative pressure transfer of fuel from said fuel chamber to said fuel delivery pump.

10. A fuel injection system as claimed in claim 7 including means providing idle fuel enrichment to the fuelair mix at the cylinders including the provision of idle signal orifices in the manifold system below the engine throttle valve when in its closed position and a communicating passage between said idle signal orifices and said closed air chamber.

11. A fuel injection system as claimed in claim 7 including an idle air by-pass means around the said throttle valve including means for regulating the flow of air th'erethrough.

12. A fuel injection system as claimed in claim 7 including means providing idle fuel enrichment to the fuel-air mix at the engine cylinders including the provision of idle signal orifices in the manifold system below the engine throttle valve when in its idle closed position and a communicating passage between said idle signal orifices and said closed air chamber, and thermostatically controlled means restricting the flow of air between the said closed air chamber and the throat of the venturi whereby to increase negative pressure created in said closed air chamber during cold engine starts.

No references cited.