US3251585A - Internal combustion engine charge forming device having temperature compensated accelerating pump - Google Patents

Description

y 7, 1966 T. J. DERENGOWSKI ETAL 3,251,585

INTERNAL COMBUSTION ENGINE CHARGE FORMING DEVICE HAVING TEMPERATURE COMPENSATED ACCELERATING PUMP Filed Sept. 3, 1963 2 Sheets-Sheet l F/GZ 7710 J DERENGOWSK/ CHARLES Gg Q QH A/Q ATTORN EYS y 1966 T. J. DERENGOWSKI ETAL INTERNAL COMBUSTION ENGINE CHARGE FORMING DEVICE HAVING TEMPERATURE COMPENSATED ACCELERATING PUMP 2 Sheets-Sheet 2 Filed Sept. 5, 1963 29 I 55 TAD J. DERENGOWSK/ 3/ CHARL ES Q QEAR WKM ATTORNEYS joyed any largecommercial success, however.

United States Patent INTERNAL COMBUSTION ENGINE CHARGE FORMING DEVICE HAVING TEMPERATURE COMPENSATED ACCELERATING PUMP Tad J. Derengowski, Dearborn, and Charles R. Goodyear, Franklin, Micln, assignors to Ford Motor Company, Dearborn, Mich., a corporation of Delaware Filed Sept. 3, 1963, Ser. No. 306,135 3 Claims. (Cl. 26134) This invention relates to -a charge forming device for an internal combustion engine and more particularly to a charge forming device having-an improved temperature compensated accelerating pump.

A charge forming device for an internal combustion engine generally incorporates an eccelerating pump that discharges a quantity of fuel into the induction passage when the throttle is rapidly opened. The supplemental fuel discharge is necessary to prevent excessive leaning out -of the mixture supplied to the cylinders during the initial change in running speed. Although the quantity of the supplemental fuel required varies with the temperature, the conventional accelerating pump discharges a fixed amount of fuel for a given throttle opening. Because of the fixed fuel discharge, the accelerating'pump must be designed for a specific temperature and will supply excess amounts of fuels at higher temperatures and insufficient amounts at lower temperatures.

It has been common to provide some form of adjustment for the accelerating pump stroke. The adjustment is generally made seasonally to provide greater pump discharge during the winter months than in the summer months, Theseasonal adjustment of the linkage is entirely unsatisfactory since it is frequently ignored and offers, at best, only a very coarse temperature adjustment. It has been proposed, therefore, to provide a temperature compensated accelerating. pump that is automatic in operation.

Numerous charge forming devices incorporating temperature compensated accelerating pumps have been proposed. None of these charge forming devices have en- The reason for the limited acceptance of the temperature compensated accelerating pumps has been their complexity and the need to substantially modify existing charge forming devices to permit their use.

It therefore is the principal object of this invention to provide an improved temperature compensated accelerating pump that may be used with minimum change to existing charge forming devices.

A charge forming device incorporating this invention includes an induction passage and throttle means for controlling the flow of air through the induction passage. Accelerator linkage means are operatively connected to the throttle means for positioning the throttle means. An accelerating pump is provided having a pumping member adapted to discharge fuel into the induction passage. A drive system for the pumping member including a drive member is connected by a resilient connection to an element of the accelerator linkage for effecting simul- Patented May 17, 1966 become more apparent when considered in conjunction with the accompanying drawings, wherein:

FIGURE 1 is a side elevational view of an internal combustion engine charge forming device embodying this invention.

FIGURE 2 is a side elevational view, in part similar to FIGURE 1, showing the components in another position.

FIGURE 3 is a top plan view of the charge forming device shown in FIGURE 1, with portions broken away.

FIGURE 4 is a top plan view, similar to FIGURE 3,

with the components shown in the positions corresponding to FIGURE 2. Referring now in detail to the drawings, an internal combustion engine charge forming device is indicated generally by the reference numeral 11. The charge forming device 11 includes a body portion 12 formed with a pair of induction passages 13 and a float chamber 14. A suitable float mechanism (not shown) is positioned in the float chamber 14 to provide a uniform head of fuel. Fuel is discharged from the float chamber 14 into the induction passages 13 by suitable idle and main fuel discharge circuits which may be considered to be conventional and are not shown in detail. A cover plate 15 is secured to the body portion 12 by a plurality of threaded fasteners 16. The cover plate 15 has an air horn 17 that forms a common air inlet to the induction passages 13. A choke plate 18 is rotatably supported upon a choke shaft 19 in the air horn 17. An automatic choke mechanism, indicated generally at 21, is provided to suitably position the choke plate 18 and provide cold weather enrichment.

A pair of throttle valves 22 are supported upon a common throttle valve shaft 23 that is journaled in the body portion 12 at the lower end of the induction passages 13. The throttle valves 22 are rotatably positioned within the induction passages 13 to control the flow of mixture therethrough by an accelerator linkage that includes a throttle :lever 24. The throttle lever 24 is afiixed to the throttle valve shaft 23 at one side of the charge forming device 11. The throttle lever 24 has an inturned tang 25 that is adapted to abut an adjustable screw 26 that is threaded through an outwardly extending ear 27 of the body portion 12 to establish a normal idle position for the throttle valves 22.

As is well known, when the throttle valves 22 are I rapidly opened, the air flow through the induction pastaneousmovement of the drive member and the element.

Thermally responsive stop means coact wit-l1 the drive sages 13 increases faster than the rate of fuel discharge from the float chamber 14 through the normal fuel discharge channels into the induction passages 13. The inertia of the heavier fuel causes the lag in fuel discharge.

An accelerating pump mechanism indicated generally at 28 is provided to inject a charge of fuel into the induction passages 13 when the throttle valves 22 are rapidly opened.

The 'acceleratin g pump mechanism 28 includes an extension 29 of the charge forming device body portion 12. The extension, 29 is formed with an internal bore that acts as a pumping chamber. A diaphragm 31 is stretched across the mouth of the internal bore and is held in place 'by accelerating pump cover plate 32 that is secured to the extension 29 by screws 33. A pumping member 34 is affixed to the center of the diaphragm to cause oscillation of the diaphragm. The pumping member 34 is reciprocally guided in the accelerating pump cover plate 32 and is spring biased in an outward direction. Reciprocation of the pumping member 34 causes the diaphragm to move back and forth to charge and discharge the internal bore in the known manner.

A pump lever 35 is pivotally supported by a pivot pin 36 upon the accelerating pump cover plate 32. The pump lever 35 has a projection 37 that extends inwardly to contact the outer end of the pumping member 34 whereby pivotal movement of the lever 35 about the pivot pin 36 results in reciprocation of the pumping member 34.

An accelerating pump drive system is provided for transmitting movement of the throttle valves 22 into pivotal movement of the pump lever 35 and reciprocation of the pumping member 34. The drive system includes an accelerating pump drive lever 38 having an integral bushing portion formed thereon that is journaled upon the throttle valve shaft 23 for rotation with respect to the throttle lever 24. A torsional coil spring 39 encircles the bushing portion of the accelerating pump drive lever 38. One end 41 of the coil spring 39 bears against an outwardly extending tang 42 of theaccelerating pump drive lever 38.

The other end 43 of the coil spring 39 bears against the inturned tank of the throttle lever 24. The coil spring normally urges the tank 42 into engagement with the throttle lever 24 and causes the throttle lever 24 and accelerating pump drive lever 38 to rotate in unison.

Rotation of the accelerating pump drive lever 38 is transmitted into pivotal movement of the'pump lever by a link 44. One end of the link 44 is bent outwardly and passes through an aperture in the upper end of the accelerating pump drive lever 33. The end 45 is retained in the aperture by a clip 46. The other end 47 of the link 44 is bent downwardly and passes through an aperture 43 formed in the outer end of the pump lever 35.

A common type of charge forming device having a conventional accelerating pump mechanism has thus far been described. Thermally responsive stop means, indicated generally at 49 are provided, however, for decreasing the stroke of the accelerating pump 28 as the temperature increases. The thermally responsive stop means 49 includes a bimetallic leaf spring 51 that is afiixed at one end thereof by a screw 52 to a substantially rigid bracket 53. The bracket 53 is secured, in turn, to the body portion 12 by a screw 54. The bimetal eifect of the leaf spring 51 is such that as the temperature increases its unsupported end deflects away from the body portion 12. The unsupported end of the bimetallic leaf spring 51 coacts with a stepped cam portion 55 formed on the pump lever 35. The length of the stepped cams formed on the portions 55 increases in relation to their distance from the body portion 12.

The operation of the thermally responsive stop means 49 may be best understood by reference to FIGURES 3 and 4 wherein the positions of the accelerator linkage, accelerating pump and accelerating pump drive system are shown with the throttle in nearly fully opened and partially opened positions, respectively. During initial opening of the throttle valve 22, rotation of the throttle lever 24 is transmitted to simultaneous rotation of the accelerating pump drive lever 38 through the coil spring 30. Rotation of the accelerator pump drive lever 38 is transmitted through the link 44 to cause pivotal movement of the pump lever 35 and reciprocation of the pump-ing member 34 to inject a charge of fuel into the induction passages 13.

At a low temperature the thermally responsive leaf spring 51 is relatively straight (FIGURE 4). In this position the end of the leaf spring 51 is contacted by the shortest of the stepped cams of cam portion 55. When the stepped cam portion 55 contacts the leaf spring 51, further pivotal movement of the pump lever 35 is precluded.- The resistance to movement transmitted through the link 44 holds the pump drive lever 38 from further rotation. The torsional coil spring 39 then yields to permit the throttle lever 24 to move independent of movement of the accelerating pump lever 38 and associated accelerating pump mechanism. The throttle valve 22, therefore, may be moved to the fully opened position without aifecting further discharge of the accelerating pump 28. At low temperatures the accelerating pump 28 delivers a substantial charge of fuel into the induction passages 13 when the throttle valves 22 are open because of the long stroke.

As the temperature of the engine increases, the bimetallie leaf spring 51 deflects with its unsupported end moving away from the body portion 12 (FIGURE 3). When the throttle valves 22 are moved toward the fully opened position, the unsupported end of the leaf spring 51 will contact the higher or longer of the stepped cam surfaces 55 to provide a substantially decreased stroke for the pumping member 34. As was previously described, when the leaf spring 51 is contacted by the stepped cam portion 55, the coil spring 39 yields to permit relative rotation between the throttle lever 24 and the accelerating pump drive lever 38.

The number of intermediate cam positions of the lever and the length and width of the individual portion will determine the number of intermediate stops of the accelerating pump as well as the various lengths of the pump strokes. These variables may be changed to suit the particular requirements of the engine.

It is to be understood that the invention is not limited to the exact construction shown and described, but that various changes and modifications may be made without departing from the spirit and scope of the invention, as defined by the appended claims.

We claim:

1. An internal combustion engine charge forming device comprising an induction passage, throttle means supported on a throttle shaft for controlling the fiow of air through said induction passage, accelerator linkage means operatively connected to said throttle means for positioning said throttle means, an accelerating pump having a pumping member adapted to discharge fuel into said induction passage, a drive system for said pumping member including a drive member rotatably supported on said throttle shaft, a resilient connection operatively connecting said drive member with an element of said accelerator linkage for effecting simultaneous movement of said drive member and said element, a thermally responsive stop means coacting with said drive member for limiting the movement of said drive member in at least one direction of its movement and causing said resilient connection to yield for further movement of said element without resulting further movement of said drive member, said thermally responsive stop means being operative to provide a decreased degree of movement of said drive member as the temperature of said thermally responsive stop means increases.

2. An internal combustion engine charge forming device comprising an induction passage, a throttle valve supported upon a throttle valve shaft in said induction passage for controlling the flow of air therethrough, a throttle lever affixed-to said throttle valve shaft for imparting rotary movement thereto, an accelerating pump having a pumping member adapted to discharge fuel into said induction passage, an accelerating pump drive lever supported for rotation upon said throttle valve shaft, said throttle lever and said accelerating pump drive lever being rotatable with respect to each other, resilient means operatively connecting said levers for simultaneous rotation, drive means for transmitting rotary motion of said accelerating pump drive lever into pumping action of said pumping member, and thermally responsive stop means for limiting the rotation of said accelerating pump drive lever in at least one direction and for causing said resilient mean to yield and permit rotation of said throttle lever without effecting rotation of said accelerating pump drive lever, said thermally responsive stop means being operative to provide a decreased degree of rotation of said accelerating pump drive lever as the temperature of said thermally responsive stop means increases.

3. An internal combustion engine charge forming device comprising an induction passage, a throttle valve supported upon a throttle valve shaft in said induction passage for controlling the flow of air therethrough a throttle lever aflixed to said throttle shaft for imparting rotary movement thereto, an accelerating pump having a pumping member adapted to discharge fuel into said induction 5 t passage, an accelerating pump drive lever supported for rotation upon said throttle valve shaft, said throttle lever and said accelerating pump drive lever being rotatable with respect to each other, resilient means operatively connecting said levers for simultaneous rotation, drive means for transmitting rotary motion of said accelerating pump drive lever into pumping action of said pumping member, and thermally responsive stop means for limiting the movement of said pumping member in at least one direction, said thermally responsive stop means including a stepped cam member connected for movement with said pumping member and a bimetallic spring fixed at one end upon said charge forming device, the other end of said bimetallic spring being adapted to contact said stepped cam member upon movement of said stepped cam member and cause said resilient connection to yield and permit movement of said throttle lever without effecting rotary movement of said accelerating pump drive lever.

References Cited by the Examiner UNITED STATES PATENTS 1,935,351 11/1933 Chandler 26l--34 2,328,604- 9/1943 Bicknell 261-34 2,355,346 8/1944 Weber 26134 X 2,394,665 2/1946 Christian 26139 2,615,694 10/1952 Olson 261-34 2,625,382 1/1953 Boyce 26l-34 2,877,996 3/1959 Kinney et a1 26134 3,167,254 1/1965 Goodyear 261-39 HARRY B. THORNTON, Primary Examiner.

T. R. MILES, Assistant Examiner.

Claims (1)

1. AN INTERNAL COMBUSTION ENGINE CHARGE FORMING DEVICE COMPRISING AN INDUCTION PASSAGE, THROTTLE MEANS SUPPORTED ON A THROTTLE SHAFT FOR CONTROLLING THE FLOW OF AIR THROUGH SAID INDUCTION PASSAGE, ACCELERATOR LINKAGE MEANS OPERATIVELY CONNECTED TO SAID THROTTLE MEANS FOR POSITIONING SAID THROTTLE MEANS, AN ACCELERATING PUMP HAVING A PUMPING MEMBER ADAPTED TO DISCHARGE FUEL INTO SAID INDUCTING PASSAGE, A DRIVE SYSTEM FOR SAID PUMPING MEMBER INCLUDING A DRIVE MEMBER ROTATABLY SUPPORTED ON SAID THROTTLE SHAFT, A RESILIENT CONNECTION OPERATIVELY CONNECTING SAID DRIVE MEMBER WITH AN ELEMENT OF SAID ACCELERATOR LINKAGE FOR EFFECTING SIMULTANEOUS MOVEMENT OF SAID DRIVE MEMBER AND SAID ELEMENT, A THERMALLY RESPONSIVE STOP MEANS COACTING WITH SAID DRIVE MEMBER FOR LIMITING THE MOVEMENT OF SAID DRIVE MEMBER IN AT LEAST ONE DIRECTION OF ITS MOVEMENT AND CAUSING SAID RESILIENT CONNECTION TO YIELD FOR FURTHER MOVEMENT OF SAID ELEMENT WITOUT

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