US2759467A

US2759467A - Fuel metering means

Info

Publication number: US2759467A
Application number: US453026A
Authority: US
Inventors: William E Leibing
Original assignee: Individual
Current assignee: Individual
Priority date: 1954-08-30
Filing date: 1954-08-30
Publication date: 1956-08-21
Anticipated expiration: 1973-08-21

Description

Aug. 21, 1956 w. E. LElBlNG 2,759,467

FUEL METERING MEANS Filed Aug. 50, 1954 s Sheets-Sheet 1 MANIFOLD INVENTOR. VV/zz /4/*7 fla a Aug. 21, 1956 w. E. LEIBING 2,759,467

FUEL METERING MEANS Filed Aug. 30, 1954 3' sheets-sheet .2

INVENTOR. VV/L/AM f1 EVE/W6 BY I 'rroe/v s Aug. 1, 1956 w. E. LEIBING 2,759,467

FUEL METERING MEANS Filed Aug. 50, 1954 3 Sheets-Sheet 3 BY am? United States Patent Office 2,759,467 Patented Aug. 21, 1956 My invention relates to fuel metering means for internal combustion engines, and included in the objects of my invention are:

First, to provide a fuel metering means for internal combustion which overcomes the principal difliculties inherent in the conventional carburetor now aggravated when used with engines having automatic transmissions.

Some of the inherent problems of the conventional carburetor are: the difficulty, if not impossibility, of obtaining eflicient operation at both high and low engine speeds; the tendency to stall the engine under load at low speed; and the inability to compensate for high and low altitudes when used in mountainous regions.

Second, to provide a fuel metering means for internal combustion engines which, while having many of the advantages of fuel injection systems, does not require the extremely close tolerances and hence does not involve the high cost of such systems.

Third, to provide a fuel metering means which may be incorporated in a carburetor so as to provide full air flow to the engine at all speeds, and simultaneously supply the correct amount of fuel for all combinations of speed and load imposed.

Fourth, to provide a fuel metering means which may be incorporated in the fuel supply system which is the subject matter of my copending application, Serial No. 348,067, filed April 10, 1953, for Injection Fuel Pump for Internal Combustion Engines.

With the above and other objects in view, as may appear hereinafter, reference is directed to the accompanying drawings, in which:

Figure 1 is a longitudinal sectional view of my fuel metering means, taken through 11 of Fig. 2;

Fig. 2 is a sectional view thereof, taken through 22 of Fig. 1;

Fig. 3 is an enlarged fragmentary sectional view of the fuel pump, taken through 33 of Fig. 1;

Fig. 4 is a fragmentary sectional view of the fuel pump and the drive means therefor, taken through 4-4 of Fig. 3;

Fig. 5 is a top view of a modified form of my fuel metering means with the float chamber cover and float removed; and

Fig. 6 is a longitudinal sectional view thereof, taken through 66 of Fig. 5.

Reference is first directed to Figs. 1, 2 and 3. The construction here used is intended to be substituted for the conventional carburetor. For purposes of illustration, a down-draft air duct 1 is shown having at its lower portion a venturi throat 2 and at its upper portion a throttle valve 3.

Secured to the side of the air duct 1 is a float housing 4 having a cover 5 to which is hinged a float 6 adapted to occupy the upper portion of the float housing 4. The float 6 operates a needle valve 7 located in the cover 5, which controls a fuel inlet 8 in the manner of the conventional carburetor float.

One side wall of the float housing 4 is provided with an aperture in which is fitted a bearing case 9 through which extends a shaft 10, suitably connected to the internal combustion engine with which my fuel metering means is used. The shaft 10 rotates at engine speed or at a fixed ratio to the engine speed.

The shaft 10 protrudes into the float housing 4 and a suitable bearing seal 11 is provided to prevent loss of fuel from the housing. The shaft 10 is connected to a fuel pump 12. The fuel pump is a small variable speed, variable displacement, sliding vane type pump, and comprises a shell 13 defining a cylindrical rotor chamber in which is mounted a rotor 14 having sliding vanes 15, which ride against the walls of the rotor chamber and are urged outwardly by springs.

The lower radial margin of the shell 13 is extended and receives a stem 16 extending parallel with the shaft 10. One end of the stem 16 projects into a socket provided in the bearing case 9, and the other end extends into a socket provided in the opposite wall of the float housing 4.

The shell 13 of the pump is provided at its upper margin with intake ports 17, suitably located with respect to the vanes 15, to supply fuel contained in the float housing 4 to the pump cavity. Discharge ports 18 extend from the lower portion of the pump cavity and communicate with the stem 16 which is provided with a bore 19.

The wall of the float housing 4 is provided with a passage which communicates with the bore 19 in the stem 16 and extends upwardly to the upper extremity of the float housing. Formed in the float housing 4 and cover 5 is a downwardly directed primary air duct 21, the lower end of which connects with an eduction tube 22 extending laterally into the air duct 1 and downwardly to the venturi throat 2. The passage 20 and primary air duct 21 are connected by a port 23 which may be formed by a recess at the upper end of the passage 20 closed by the cover 5. An orifice disc 24 is located in the passage 20 below the port 23, and a second orifice disc 25 is located at the discharge end of the eduction tube 22.

Suitably supported above the primary air duct 21 is a choke plug 26 which may be automatically or manually moved into the open upper end of the primary air duct 21 to control the amount of air supplied and the pressure existing in the primary air duct.

Centered in opposite sides of the float housing 4, on an axis passing through the pump at right angles to the shaft 10, are apertures of equal area sealed by diaphragms 27 and 28. One of these diaphragms is enclosed at its outer side by a shell 29 to form therewith an atmospheric pressure compensator 30. The other diaphragm is enclosed by a housing 31 to form a pump controller 32. The space within the atmospheric pressure compensator 30 is filled with inert gas or fluid which expands and contracts with change in atmospheric pressure.

The housing 31 of the pump controller 32 is provided with a vacuum port 33 for connection to the intake manifold of the associate internal combustion engine so that the pressure within the pump controller 32 corresponds to the pressure in the intake manifold. A spring 34 is mounted within the housing 31 and bears against the diaphragm 28. Protruding from the housing 31 is an adjustment screw 35 for adjusting the force exerted by the spring 34.

The diaphragms 27 and 28 are provided with stems 36 and 37, respectively, which are joined by a yoke 38 which is U-shaped in form so as to clear the pump 12. Attached to the stem 37 is a lever 39 which fulcrums on a pivot 40 extending from the wall of the float housing 4. A link 41 extends from the lever 39, near the pivot 40, to an arm 42 extending upwardly from the pump 12.

Operation of my fuel metering means is as follows:

The float housing 4 is maintained full of fuel to a level slightly below the port 23. The shell 13 of the pump 12,

which is submerged in the fuel, is capable of a rocking movement about the axis of the stem 16 so as to vary the capacity of the pump.

Fuel is drawn in through the intake ports 17 and delivered through the stem 16 and passage 20- to the port 23. For a given pump speed, the volume of fuel delivered depends upon displacement of the pump; that is, upon the eccentricity of the shell 13 relative to the rotor 14. The fuel discharging from the port 23 is entrained in primary air drawn through the primary air duct 21. The primary mixture of fuel and air is delivered to the air duct 21 through the eduction tube 22.

The fuel pump shaft may rotate at engine speed, or in proportion to engine speed, preferably at one-half engine speed.

Assuming that the engine is idling without load, a relatively high vacuum will occur in the pump controller 32, moving the diaphragm 28 to the left, as viewed in Fig. 2, that is, in a direction to reduce the eccentricity of the pump shell 13 and thereby reduce the capacity of the pump. The eduction tube 22 under such conditions is subjected to very low pressure in the air duct 1, but the primary air duct 21 will be at approximately atmospheric pressure. Such fuel as is delivered by the pump will be discharged through the port 23, but there will be no appreciable vacuum pressure in the passage 20.

Now, if a load is imposed on the engine while the engine is still at idle position, the vacuum in the pump controller 32 will be relieved, moving the diaphragm 28 to the right, as viewed in Fig. 2, so as to increase the capacity of the pump. This will ensure an added discharge of fuel into the primary air duct 21, for delivery with the primary air to the venturi throat 2. Thus, even before the engine speed increases, an enriched supply of fuel is delivered, preventing the engine from stalling when a load is imposed at idle position. It should be observed that when the engine is employed in a vehicle having an automatic transmission, loads are imposed on the engine while in idle position. Therefore, with the arrangement shown, the tendency for the engine to stall is minimized.

Now, again, assuming an idle condition, if the throttle 3 is opened for purposes of acceleration, the first result is to release Whatever vacuum may exist in the pump controller 32, causing the pump to move to its position of maximum capacity for the speed at which it is operated. If the load on the engine is high and therefore the speed relatively low, the enriched fuel needed is delivered. If the throttle 3 remains wide open and the engine speed increases, the pump also increases in speed and more fuel is delivered. Thus, if the engine speed is doubled the pump speed is doubled and the fuel delivered is doubled, assuming that the manifold or intake pressures remain constant.

With reference to the atmospheric compensator 30 and assuming that the engine is in idle position at 10,000 ft. altitude, the atmospheric pressure is approximately four pounds less than at sea level. The pressure within the sealed compensator 34) remains at sea level pressure, exerting a force to the left, as viewed in Fig. 2, and tending to reduce in proportion the capacity of the fuel pump. The diaphragms preferably have equal effective areas so that the correction introduced by reason of the atmospheric pressure maintained in the compensator 30 is just suflicient to reduce the fuel supplied to correspond with the reduced atmospheric air pressure. This is true irrespective of the engine speed. It thus will be seen that for all throttle positions and for all engine speeds the fuel is supplied in proportion to the need of the internal combustion engine and that there is a minimum hysteresis between a change in demand and a corresponding change in supply.

It should be noted that the air duct 1 may be a single air duct connected to a manifold leading to all of the cylinders of a combustion engine or to a bank of such cylinders, or even to one. In such a case my fuel metering means is duplicated, or the pumps merely duplicated with independent discharge passages.

It should be observed that the function of the pump 12 is merely to lift fuel from the level of the fuel in the float chamber to the level of the port 23. This need be only a fraction of an inch so that the pressure differential is almost negligible. As a consequence, the tolerance requirements of the parts comprising the pump are much less severe than would be the case if the pressure differentials were greater.

It should be observed that it is sometimes desirable to provide a leaner fuel mixture at high engine speed and wide open throttle. This can be accomplished by low tolerances in the construction of the pump so that its efficiency decreases as the back pressure increases, and by providing an orifice or meter disc 24 at the upper end of the passage 20. At high engine speeds a back pressure is created in the passage 20 thereby reducing the effective capacity of the pump. At low engine speeds, the orifice meter disc 24 offers little resistance to flow.

Leakage past the pump may be also employed when starting the internal combustion engine cold. This involves use of the choke plug 26. By lowering the choke plug 26 into the primary air duct 21, the air pressure in the duct 21 is reduced and a vacuum is introduced into the passage 20 so that the fuel delivered is in excess of the amount actually being pumped. Thus in starting, the air fuel ratio is enriched. As the engine warms up, the choke plug 26 is manually or automatically withdrawn. Thus it will be seen that an inexpensive pump, the parts of which are loosely fitted, may be employed advantageously.

Reference is now directed to Figs. 4 and 5. The construction here illustrated is an application of my present fuel metering means to my fuel engine system disclosed more fully in my copending application filed April 10, 1953, Serial No. 348,067, for Injection Fuel Pump for Internal Combustion Engines.

In my copending application I have disclosed a variable capacity pump which delivers fuel from a float chamber to the intake manifold or engine cylinders. In the present embodiment of my invention, I employ the pump 12 submerged in a float chamber for metering the fuel to the injection pump. The injection pump includes a cylinder block 43 in which is set a ring of cylinder liners 44 disposed with their axes parallel. The liners are equipped with pistons 45 which are joined by connecting rods 46 to a wobble plate 47 rotated by a drive shaft 48. One end of the cylinder block and Wobble plate is enclosed in a housing 49.

Bearings

50 and 51 fit in the housing 49 and the cylinder block 43 supports the drive shaft 48.

The opposite or upper end of the cylinder block 43 is covered by an adapted plate 52 on which is secured a float housing 53 provided with a cover 54. Supported from the cover 54 is a float 55 which controls a needle valve 56. At the bottom of the flat housing 53 on the adapter plate 52 is mounted a fuel pump 12, similar to the fuel pump shown in the first described structure.

The drive shaft 48 is provided with a tubular drive shaft extension 57 which extends upwardly through the pump 12 to a point above the fuel level in the float housing 53 and terminates in a fuel-receiving funnel 58. A tube 59 communicates with the bore 19 in the stem 16 of the pump, extends upwardly within the float housing 53 and terminates in a gooseneck 60, discharging into the funnel 58.

The bore of the drive shaft extension 57 extends into the cylinder block 43 and communicates with a lateral bore 61 adapted in turn to communicate successively with radial passages 62. The radial passages communicate with intake ports 63 in the cylinder liners 44.

The lower portion of the float housing 53 is provided With a flange having discharge ports 64 leading from the cylinder liners 44. The discharge ports 64 are provided page with check valves 65 and are connected by suitable liners, not shown, to the intake manifold or cylinders of an internal combustion engine, as more fully set forth in my copending application.

Mounted in opposite side walls of the float housing 53 is an atmospheric compensator 30 and pump controller 32, as in the first described structure. These are connected by a yoke 66 which extends across the float housing 53 and is offset to clear the shaft extension 57. At one side of the float housing 53 there is provided a boss 67, which supports a post 68 on which pivots a rocker 69 having an arm 70 joined to the yoke 66, and a second arm 71 connected by a link 72 to the arm 42 of the pump 12.

Operation of the construction shown in Figs. 5 and 6 is the same as in the first described structure, except that the fuel instead of being delivered directly to an air duct is delivered to an injection pump.

It should be noted that the cover 54 of the float chamber is perforated so that air may be admitted which may be entrained with the fuel discharged into the receiving funnel 58. By reason of the fact that the shaft extension 57 rotates, the fuel tends to form a film on the Walls thereof as it flows downward. The pressure differentials created by the operation of the pistons 45 ensure downward flow of the fuel against any centrifugal force that would tend to drive the fuel upwardly into the receiving funnel 58.

It should be observed that the receiving funnel 58 may be quite small at its maximum diameter, as the tube 59 and its discharge end moves only a nominal amount with movement of the pump shell, that is, the capacity of the pump 12 is quite small so that the movement of the shell from its concentric position to its position of maximum eccentricity may be, for example, less than one-eighth inch. In fact, for the average automobile engine the lateral displacement of the shell may be in the range of .015" for either embodiment shown.

Having fully described my invention, it is to be understood that I do not wish to be limited to the details herein set forth, but my invention is of the full scope of the appended claims.

I claim:

1. A fuel metering means for an internal combustion engine adapted to operate at various speeds and having an air intake manifold in which the pressure varies, comprising: a float chamber for liquid fuel; means for maintaining the liquid fuel therein at approximately a predetermined level; a fuel pump submerged in the liquid fuel in said float chamber, said fuel pump having a variable capacity dependent upon the speed at which said pump is driven and including relatively movable elements operable to vary the displacement of said pump at any of its operating speeds, said pump having a discharge end above and in proximity to said liquid level; means for driving said fuel pump at a speed corresponding to the speed of said internal combustion engine; means for regulating the volumetric capacity of said fuel pump in correspondence with the pressure in said intake manifold; and means for mixing air with the fuel at the discharge end of said pump for delivery to said internal combustion engine.

2. A fuel metering means as set forth in claim 1, wherein: said float chamber is associated with an air supply duct having a venturi throat and communlcatmg with the intake manifold of an internal combust on engine; and said air mixing means is a primary air duct including an eduction tube discharging into said venturi throat.

3. A fuel metering means as set forth in claim 1, wherein: said float chamber is associated with a fuel injection pump, and said air mixing means includes passageways adapted to conduct said fuel and primary air to said injection pump.

4. A fuel metering means as set forth in claim 1, wherein: said float chamber is associated with an air supply duct having a venturi throat and communicating with the intake manifold of an internal combustion engine; and said air mixing means is a primary air duct including an eduction tube discharging into said venturi throat; means are provided to restrict air flow in said primary air duct to decrease the pressure therein thereby to apply a suction pressure to the discharge end of said pump; and said pump is constructed and arranged to pass excess fuel when said discharge end is subjected to vacuum pressures.

5. A fuel metering means for an internal combustion engine adapted to operate at various speeds and having an air intake manifold in which the pressure varies, comprising: a float chamber for liquid fuel; a variable speed, variable displacement fuel pump submerged in the liquid fuel in said float chamber; means for driving said fuel pump at a speed corresponding to the speed of said internal combustion engine; means for regulating the displacement of said fuel pump in correspondence with the pressure in said intake manifold; and means for mixing air with the fuel discharged from said fuel pump for delivery to said internal combustion engine.

6. A fuel metering means for an internal combustion engine adapted to operate at various speeds and having an air intake manifold in which the pressure varies, comprising: a float chamber for liquid fuel; a fuel pump submerged in the liquid fuel within said float chamber including a rotor having impellers, a shell enclosing said rotor and movable eccentrically relative to said rotor to define a pump having variable speed and variable displacement; means for driving said rotor at a speed corresponding to the speed of said internal combustion engine; means for moving said shell in correspondence with the vacuum pressure in said intake manifold to decrease the effective displacement of said pump with decreased manifold pressure and to increase the effective displacement of said pump with increased manifold pressure; and means for mixing air with the fuel discharged by said pump for delivery to said internal combustion engine.

7. A fuel metering means as set forth in claim 6, wherein: said float chamber is associated with an air supply duct having a venturi throat and communicating with the intake manifold of an internal combustion engine; and said air mixing means is a primary air duct including an eduction tube discharging into said venturi throat.

8. A fuel metering means as set forth in claim 6, wherein: said float chamber is associated with a fuel injection pump, and said air mixing means includes passageways adapted to conduct said fuel and primary air to said fuel injection pump.

9. A fuel metering means as set forth in claim 6, wherein: said float chamber is associated with an air supply duct having a venturi throat and communicating with the intake manifold of an internal combustion engine; said air mixing means is a primary air duct including an eduction tube discharging into said venturi throat; means are provided to restrict air flow in said primary air duct to decrease the pressure therein thereby to apply a suction pressure to the discharge end of said pump; and said pump is constructed and arranged to pass excess fuel when said discharge end is subjected to vacuum pressures.

10. A fuel metering means for an internal combustion engine adapted to operate at various speeds and having an air intake manifold in which the pressure varies, comprising: a float chamber for liquid fuel; means for maintaining the liquid fuel therein at approximately a predetermined level; a variable speed, variable displacement fuel pump having an inlet disposed below said liquid fuel level, and an outlet disposed above but in proximity to said liquid fuel level; means for driving said fuel pump at a speed corresponding to the speed of said internal combustion engine; means for regulating the volumetric capacity of said fuel pump in correspondence with the pressure in said intake manifold; and means for mixing air with the fuel at the discharge end of said pump for delivery to said internal combustion engine.

11. A fuel metering means as set forth in claim 10, wherein: said float chamber is associated with an air supply duct having a venturi throat and communicating with the intake manifold of an internal combustion engine; and said air mixing means is a primary air duct including an eduction tube discharging into said venturi throat.

12. A fuel metering means as set forth in claim 10, wherein: said float chamber is associated with a fuel in- 'jection pump, and said air mixing means includes passageways adapted to conduct said fuel and primary air to said fuel injection pump.

13. A fuel metering means as set forth in clairri 10, wherein: said float chamber is associated with an air supply duct having a venturi throat and communicating with the intake manifold of an internal combustion engine; said air mixing means is a primary air duct including an eduction tube discharging into said venturi throat; means are provided to restrict air flow in said primary air duct to decrease the pressure therein thereby to apply a suction pressure to the discharge end of said pump; and said pump is constructed and arranged to pass excess fuel when said discharge end is subjected to vacuum pressures.

14. A fuel metering means for an internal combustion engine adapted to operate at various speeds and having an air intake manifold in which the pressure varies, com prising: a float chamber for liquid fuel; means for maintaining the liquid fuel therein at approximately a predetemined level; a variable speed, variable displacement fuel pump including a rotor having impellers, a shell enclosing said rotor and movable eccentrically relative to said rotor to define a pump chamber of variable displacement, said pump chamber being disposed below the liquid fuel level maintained in said float chamber and having an inlet communicating therewith, and a discharge end for said pump located above but in proximity to said liquid fuel level; means for driving said fuel pump at a speed corresponding to the speed of said internal combustion engine; means for regulating the displacement of said fuel pump in correspondence with the pressure in said intake manifold; and means for mixing air with the fuel at the discharge end of said pump for delivery to said internal combustion engine.

15. A fuel metering means for an internal combustion engine adapted to operate at various speeds and having an air intake manifold in which the pressure varies, comprising: a float chamber for liquid fuel; a variable speed, variable displacement fuel pump submerged in said fuel; a pair of diaphragms of substantially equal effective area, each exposed at one side to the liquid fuel in said float chamber; a sealed chamber covering the opposite side of one of said diaphragms and tending to maintain a constant pressure "on said diaphragm irrespective of the ambient atmospheric pressure; a second chamber covering the other of said diaphragms and connected with the intake manifold of said internal combustion engine to maintain in said second chamber a pressure corresponding to the intake manifold pressure; means connecting said diaphragms for movement in unison; means connecting said diaphragms with said pump to vary the displacement thereof on movement of said diaphragms; an adjustable yieldable means controlling movement of said diaphragms to regulate the effect thereof on said pump; and means for mixing air with fuel discharged by said pump for delivery to said internal combustion engine.

16. A fuel metering means for an internal combustion engine adapted to operate at various speeds and having an air intake manifold in which the pressure varies, comprising: a float chamber in liquid fuel; a variable speed, variable displacement fuel pump including a rotor having impellers, a shell enclosing said rotor and movable eccentrically relative to said rotor to define a pump chamber of variable displacement, said pump chamber being disposed below the liquid fuel level maintained in said float chamber and having an inlet communicating therewith, and a discharge end for said pump located above but in proximity to said liquid fuel level; a pair of diaphragms of substantially equal eifective area, each exposed at one side to the liquid fuel in said float chamber; a sealed chamber covering the opposite side of one of said dia phragms and tending to maintain a constant pressure on said diaphragms irrespective of the ambient atmospheric pressure; a second chamber covering the other of said diaphragms and connected with the intake manifold of said internal combustion engine to maintain in said seco'nd chamber a pressure corresponding to the intake manifold pressure; means connecting said diaphragms for movement in unison; means connecting said diaphragms with said pump to vary the displacement thereof on movement of said diaphragms; an adjustable yieldable means controlling movement of said diaphragms to regulate the effect thereof on said pump; and means for mixing air with fuel discharged by said pump for delivery to said internal combustion engine.

References Cited in the file of this patent UNITED STATES PATENTS 1,164,093 Houghton et al Dec. 14, 1915 1,894,510 Ensign Jan. 17, 1933 2,031,379 Mathieu Feb. 18, 1936 2,562,656 Blakeslee July 31, 1951 FOREIGN PATENTS 931,268 France Feb. 18, 1948