US2594662A

US2594662A - Metering fuel pump

Info

Publication number: US2594662A
Application number: US65031A
Authority: US
Inventors: William E Leibing
Original assignee: Individual
Current assignee: Individual
Priority date: 1948-12-13
Filing date: 1948-12-13
Publication date: 1952-04-29
Anticipated expiration: 1969-04-29

Description

April 29, 1952 w. E. LEIBING 2,594,662

METERING FUEL PUMP Filed DEC. 15, 1948 el* Y im Patented Apr. 29, `1952 UNITED'A STATES ATENT OFFICE METERING FUEL PUMP William E. Leibing, Los Angeles,-alif.

Application December 13, 1948, Serial No. 65,031

Claims.v (Cl. 10S-161) Y f lating the richness of the mixture so that the y proper proportions of fuel and air can be admitted to `the engine. Such adjustments are ordinarily made to meet sea level conditions;

that is, the fuel delivery at full load and the fuel delivery at idling are adjusted so that the engine operates at a maximum efficiency under the barometric pressure existing at sea level. If the engine as adjusted is later operated at high elevation the lower barometric pressure has the effect of reducing the proportion of air admitted for combustion, with the result that the fuel air mixture becomes too rich. The problem of making proper correction for altitude is complicated by the fact that it has been found that substantially no correction is required for idling. It is known that the iiow of air through arestriction increases in proportion to the pressure difference across the restriction up to a certain point. Thus air flow through a throttle valve of an engine under the action of manifold vacuum pressure increases in proportion to the vacuum up to about fourteen inches of mercury, but higher vacuum pressures do not appreciably increase the flow at all. Hence, the throttle valve on the internal combustion engine which normally idles atsea level with about twenty inches of mercury vacuum in the intake manifold will pass the same amount of air at six thousand feet altitude as it will at sea level, and therefore the same amount of fuel should be delivered to theengine when idling at six thousand feet as when. idling at sea i level.

Accordingly, it is the principal object of this generally designated-I1.

elements includes a radially-movable piston I8,y a flexible sealing Vdiaphragm I9, and a compres-V invention to provide a metering fuel pump for embodies `certainimprovements ovenmy copend-- z ing applications, Serial No. 783,106, filed Decerrr z. ber 1, 1947; and Serial No. 7,250, filed February 1 9, 1948, which matured into Patent No. 2,557,508 on June V19, 1951.

Another Objectis to provide a sealed metallic bellows or the like operable. through a yoke to reduce the output of the fuel pump when atmospheric pressure is reduced.

Other objects hereinafter.

In the drawings:

llgure--ly is -a sectional planview showing a preferred embodiment of `my invention.

Figure 2 is a transverseA sectional elevation. taken substantially onuthe lines 2-2 asshown in Figurel.

Figure3 is a longitudinal section taken substantially on the lines 3 3 as shown in Figure l.

' Figure 4 is a perspective view-showing a preferred construction of the yoke.

Referring to the drawings, a easing I is provided with spaced aligned bearings II and I2 for supporting rarotor shaft I3 adapted to be driven from its-projecting endY I4. The projecting end I isi-provided with a suitable keyway I5 so that the shaft may be driven in timed relation with the rotation of the crank shaft or cam shaft of an internal combustion engine.- A rotor I6 is fixed on the shaft and turns within the casing Ill.

Thesirotor is provided with a single or double` series of `positive displacement pump elements Each of these pump sionspring 20. A sleeve 2l encircles the rotor I6 and is adapted to rotate therewith. The sleeve 2| is carriedfon a bearing 22 within a ring 23 which is pivotally mounted on the housing at 24.

Clearance-is `provided within the housing so that thefring 23- can be shifted about its pivotal support 211. Such shifting movement of the ring 23 and. sleeve 2| relative to the rotor I6 develops eccentricity of the sleeve 2l and hence the lindividual pump pistons I9 reciprocate radially as the rotor I6 isturned. rlfhis reciprocation is used to pump fuel from an inlet 25 to spaced outlets .l

.26 and 21. The passage of the fuel vfrom the inlet- 25 to the outlet 26 is by way of the passageway A23, chamber 29, inlet passage 30 and port 3I in the sealing washer 32. The discharge from the series of pump units IIon the left side of the rotor as viewed in Figure 3 occurs through outlet port 33 in the washer32outlet passage 34 and chamber 35.; The `member 36 which supports the sealing washenlgmaybe; resiliently supported on and.Y advantages will appear the springs 31. The right hand series of pump units |1 as shown in Figure 6 act to pump fuel from the inlet 25 to the outlet 21 by way of the sealing washer 38. The porting and series f passageways for the sealing washer 38 are similar to those described in connection with the sealing washer 32.

Means are provided for shifting the ring 23 in response to variations in vacuum pressure in the inlet manifold of the internal combustion engine. The vacuum pressure is communicated to the vacuum chamber 39 by way of the inlet 40. The flexible diaphragm 4| at one end of the chamber 39 is connected to a control element 42 which extends through the diaphragm 4| and forms a seal therewith. The control element 42 is provided with a central projection 43 which carries a transverse pin 44. A lever 45 which comprises a pair of duplicate elements 46 is pivoted at one end to the pin 44 and at the other end to the pin 41. The pin 41 is mounted in the member 48 which is pivotally supported in the housing I9 on the pivot pin 49. The spring 50 acts to maintain the member against the adjustable stop A link 52 is pivotally connected to the lever at 53 and to the ring 23 at 54. Accordingly, movement of the control member 42 moves the lever 45 about the pivot pin 41 and hence shifts the ring 23 about its pivotal support 24. A spring 55 is mounted within the chamber 39. This spring engages the member 42 at one end and a stop collar 5S at the other end. An adjustable set screw 51 extends through the wall of the casing to contact the stop collar 56.

A yoke member generally designated 58 is formed of a pair of end sections 59 and 60, each having an oval shaped opening 6I. The member 59 is provided with

end walls

62 and 53 having tabs 64. The tabs 64 are adapted to extend through apertures 85 provided in the member 60, and the yoke assembly is completed by the insertion of suitable cotter pins 66 Within the openings 61 to retain the members 59 and 60 in assembled relationship about the rotor I6. The oval shaped openings 5| are sufficiently large so that the yoke does not contact the rotor at any time. A pair of ears 58 are provided on the end wall 63, and these ears are pivotally mounted on the pin 44 so that the yoke 58 is pivotally connected to the control member 42.

A metallic seal bellows 19 is mounted within the housing I0 and is attached to the end wall 62 of the yoke 58 by means of a screw 1| or other suitable attachment means. The location of the bellows 1D is diametrically opposed to the location of the diaphragm 4|. The outer end of the bellows is carried on a threaded pin 12 which extends outwardly through the wall of the housing and is provided with a lock nut 13. The sealed bellows 10 may contain air if desired, but I prefer to use a gas with a low coefficient of expansion such as, for example, helium gas or hydrogen gas.

An arm is xed to the pivot shaft 49 at a location outside of the housing |0. This armv is adapted to be actuated by a suitable rod (not shown) in order to increase the rate of delivery of fuel under cold starting conditions. Counterclockwise movement of the lever 15 as shown in Figure 2 moves the tting 48 to compress the spring 59 and to move the lower end of the lever 45 toward the left, thereby causing the links 52 to move the ring 23 to increase its eccentricity.

In operation the rotor shaft |3 is driven in timed relation with the engine and turns the rotor I6 and sleeve 2| within the nonrotary ring 23. The position of the ring 23 determines the amount of eccentricity of the sleeve 2|, and accordingly regulates the stroke of the individual pump units |1 as they rotate with the rotor I6. When the vacuum pressure in the engine manifold is high relatively little fuel is required. Thus, when the engine is idling the fuel requirements are at a minimum and the manifold Vacuum pressure is high. This vacuum pressure is transmitted to the vacuum chamber 39. Atmospheric pressure within the casing acts on the exposed area of the diaphragm 4| and moves the control member 42 to the right as shown in Figure 2 against the action of the spring 55. Atmospheric air reaches the interior of the housing I0v by way of the screen plug assembly generally designated 14. When the engine is equipped with a super charger the screen plug assembly 14 is removed so that the interior of the housing I0 may be connected with the air induction system between the super charg'er and the throttle valve of the engine (not shown), so that the pressures within the housing are those pressures which are available to the engine.

The set screws 51 and 12 are adjusted so that the lower vacuum pressure, when the engine operates at full throttle and full load at sea level, is eifective to provide the proper rate of fuel delivery.

When idling at sea level there is a balance between the spring 55 plus the effect of the bellows 19 on one hand and the resultant thrust on the. v diaphragm 4| under idling conditions on the oth-Y er hand. The idling position of the control member 42 as thus determined does not change when the engine is operating at high altitude be- Y fuel is delivered to the engine when idling, re- I' gardless of elevation.

The diaphragm pump elements |1 which op-` Y l erate within the rotor are spring actuated towardv their outer position, and as each of the springs are of substantially equal tension it follows that the sleeve 2| always tends to center itself around the rotor, for when so centered all springs 20 within the rotor I6 are under equal compression.

To shift the sleeve2| to the position of maximum eccentricity as shown in Figure 2 requires a considerable effort of spring 55 and of bellows 19. The spring 55 and bellows 19 are correspondingly set at sea level to maintain the proper eccentricity of the sleeve 2| to deliver the correctY amount of fuel to the engine for full power. Accordingly, when the engine operates under full load at a high altitude the bellows 10 becomes considerably weaker in that the internal pressure is greater than the external pressure. Accordingly, the yoke 58 will be shifted toward the right as viewed in Figure 2, reducing the eccentricity of the sleeve 2| and therefore reducing the amount of fuel pumped. Since the engine is operating at full load, the manifold vacuum pressure approaches zero, and hence the diaphragm 4| plays no part in positioning the yoke 58. It has been found from experience that intermediate positions between full throttle and idling position are well compensated for by the mechanism disclosed, and that once both limits or extreme positions are chosen the intermediate positions operate satisfactorily.

A small amount of grow of the bellows upon application of heat is a desirable feature for it-acts as an automatic enrichment means for the eng-ine upon cold starting conditions. By the proper selection of the size of the bellows any greater or lesser amount of correction for altitude can be obtained, and by using different gases within the bellows different degrees of automatic cold start effectiveness can be had.

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. In a pump, the combination of a housing; a rotor mounted to turn in the housing; a plurality of positive displacement pump elements mounted for radial movement on the rotor; a rotatable sleeve encircling the rotor and cooperating with each of said pump elements; means including a movable member in the housing adapted to shift the sleeve to vary the stroke of the pump elements; vacuum operated means adapted to shift the position of said movable member and thereby vary the rate of delivery of fuel from said pump elements; altitude correction means including an expansible sealed member mounted within the housing on the opposite side of the rotor from said vacuum operated means; and means connecting the sealed member with said movable 6 able member in the housing adapted to shift the ring; vacuum operated means adapted to shift the position of the member and thereby vary the rate of delivery of fuel from said pump elements; altitude correction means mounted within the housing on the opposite side of the rotor from said vacuum operated means for decreasing the fuel delivery rate from said pumpelements, said means including a sealed bellows connected with said movable member whereby movement of the control member under high vacuum conditions is resisted by lengthening of the bellows.

member whereby the sealed member may act in tension to oppose the action of the vacuum operated mea-ns under high vacuum conditions and to shift the movable member in a direction to -reduce the stroke of the pump elements under low vacuum conditions.

2. In a pump, the combination of a housing; a rotor mounted to turn in the housing; a plurality of positive displacement pump elements mounted for radial movement on the rotor; a rotatable sleeve encircling the rotor and cooperating with each of said pumps; means including a movable member in the housing adapted to shift the sleeve to vary the stroke of the pump elements; vacuum operated means adapted to shift the position of said movable member and thereby vary the rate of delivery of fuel from said pump elements; altitude correction means including a sealed bellows mounted within the housing on the opposite side of the rotor from said vacuum operated means and coaxially therewith; and a yoke connecting the bellows member with said movable member whereby the bellows member may act in tension to oppose the action of the vacuum operated means under high vacuum conditions and to shift the movable member in a direction to reduce the stroke of the pump elements under low vacuum conditions.

3. In a fuel pump, the combination of a hous-nI ing; a rotor mounted to turn in the housing; a plurality of positive displacement pump elements movably mounted on the rotor; a nonrotary ring in the housing having a rotatable sleeve thereon encircling the rotor and cooperating with each of said pumps, the ring and sleeve being shiftable to vary thefstroke of the pump elements; a movring and sleeve being shiftable to vary the stroke' 4. In a fuel pump, the combination of a housing; a rotor mounted to turn in the housing and driven by the engine; a plurality of positive displacement pump elements movably mounted on the rotor; a rotatable sleeve encircling the rotor and cooperating with each of said pumps; means including a movable member in the housing adapted to shift the sleeve to vary the stroke of the pumpv elements; means actuated by vacuum pressure adapted to shift the position of said member vand thereby vary the rate of delivery ci' fuel from said pump elements; and altitude correction means including a sealed bellows mounted within the housing on the opposite side of the rotor from said vacuum operated means and connected with said movable member whereby movement of the control member under high vacuum conditions is resisted by lengthening of the bellows.

5. In a fuel pump, the combination of a housing; a rotor mounted to turn in the housing 'and driven by the engine; a plurality of positive displacement pump elements movably mounted on the rotor; a nonrotary ring in the housing having a rotatablev sleeve thereon encircling the rotor and cooperating with each of said pumps, the

of the pump elements; a movable member in the housing adapted to shift the ring; vacuum operated means adapted to shift the position of said member and thereby vary the rate of delivery of fuel from said pump elements; altitude correction means including a sealed bellows mounted within the housing on the opposite side of the rotor from said vacuum operated means; and a yoke connecting the bellows member with said movable member whereby the bellows member may act in tension to oppose the action of the vacuum operated means under high vacuum conditions and to shift the movable member in a direction to reduce the stroke of the pump elements under low vacuum conditions.

WILLIAM E. LEIBING.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS