AU511472B2 - Carburettor accelerator pump - Google Patents

Description

INTVW-; Jilf Convention opnoInsert C C0 ap..."neion"

COMMONWEALTH OF AUSTRALIA

Patents Act

~~*PLICATION FOR A P+TEPA Insert FULL k I I/We GN A OOSC ams) aPa ts5) e

Insert FULL Of (c) G-rand Bov.l evard., address~es) of applicant(s) Detroit, 11-ichigart, TTTITilf Q"T' TES~ OF AIMRICA

hereby apply for the grant of a Patent for an invention entitled Insert TITLE (d) ot. Invention

Carburetter Aceelerator 'lump

e)Insert at"complete' which is described in the accompanying (e) fo 'rovisiootai f co r'uJ 11)I e specification. f

(Note: The following paragraph applies &nly to Convention applications)

This application is ;I Convention application based on the basic application(s) for a filn ateo

ftho EACH paten', (r similar protection identified by number, country, and filing date as follows: basi appicaio

u7 1. 674. 560 lTTIrn7I C1 L Ir1 7t 9

ft. ft ft ft 0Cft

ft. 4 ft ft ft ft.. A 4 \Ujj

Vill 6rAM1V TO NIL-

ft ft. ft ft ft ft ft. MAIL. oFFXE

Address for Service: PHILLIPS ORMONDE AND FITZPATRICK Patent and Trade rk Attorneys 37- 1 Queen Street Melbourne, Australia

Insert DATE or siunlug Dated 1 6th 11arch, 19 77

Signature or appilicant(s) ,(GE.N1ERAL MOTOIRS CORPORATION (For body attorneys 1, n:'T):rz u'~i -4'ts patent corprt sre edote) 7)n- 1 corporate seal if any maR1977 Note. No ieisslizatlon or othter Witness rcquire d

STUAR?TAYLOR PHILLIPS, ORMONDE AND FITZPATRICK Patent and Trade Mark Attorneys Melbourne, Australia

1 7

COMMONWEALTH OF AUSTRALIA

Patets Act

DECLARATION FOR A PATENT APPLICATION

In support of the Convention irnJCT!4tis application made by GENERAL MOTORS CORPORATION (hereinafter 4rt c4,Wntnn called "the applicant") for a patent (c) f p ll e for an invention entitled:- Carburetter Accelerator Pump

John Neil Bower Breakwell, I, :~,ihddxthr c- txtm^, Chartered Patent Agent of Grosvenor Garjens House, Grosvenor Gardens, London SWIW OBS, England do solemnly and sincerely declare as follows:-

1. I am authorized under a power of attorney from the applicant granted on* resl~ c d to make this declaration on behalf of the applicant. 1 1 January 1975

Rushmore Rowley Valentine Jr, a Citizen of Si the United States of America of 24 Rouge 99 Road, Rochester, New York 14623, United States of America.

9

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*c 0 0 is/aacthe actual inventor(X) of the invention and the applicant is entitled to make the application by virtue of a service agreements) between the applicant and the inventor(Y) as employee(s) and an assignment() from the inventor(X) to the applica.t.

3. The basic application(X) for patent or similar protection 9. on which the application is based is/De6 identified by 90 country, filing date and basic applicant(x) as follows:

United States of America S. 9 9 7 April 1976 a Rushmore Rowley Valentine Jr.

4. The basic application(s) referred to in paragraph 3 here- of was/mx=e the first application(x) made in a Convention 9 country in respect of the invention the subject of the application.

Declared at: London

Dated: 8 March 1977 I' For and on behalf of GENERAL MOTORS CORPORATION

.er U Powe r of At to r n ey Vi

A k(11) AU-B 1-23,382/77

(12) PATENT SPECIFICATION ABRIDGEMENT (19) AU

(21) 23,382/77 511,472 (22) 18.3.77 (23) 18.3.77 (24) 7.4.76 (31) 674560 (32) 7.4.76 (33) US (43) 21.9.78 (44) 21.8.80 (51)2 F02M 7/08 (54) Carburettor accelerator pump (71) General Motors Cornoration (72) Valentine, R.R. Jr., '74) PO (56) 50,265/64 283,158 66.7; 66.5 4,3r3/51 151,911 66.5 (57) Claim 1. A carburetter in which a main metering orifice opens from a fuel bowl into a wain futl passage which extends to a fuel-air mixture conduit, and an accelerator pump cavity has an inlet from said fuel bowl and a discharge passage which extends from the base of said cavity to said mixture conduit; and in which the accelerator Dump comprises an actuator sLSm which extends iato said cavity, a pump head which is arranged in said cavity to form in the base of said cavity a pump chamber, said head having a central opening slidably receiving said actuator stem, and a spring which extends between sa stem and s.id head for moving said head in a directio; to discharge said pump chamber and deliver fuel therefrom through said dischar passage to said conduit, but which is compressible to permit movement of said stem in said pump discharging' direction mo~e rapidly than sa~d head, said stem having an upwardly facing annular shoulder engageable by a downwardly facing annular shoulder on said head, and said shoulders being separable to foim an annular space opening to said pump chamber upon a pre- determined compression of said spring and predetermined separation of said shoulders to permit a portion of the fuel in said pump

Dl 31. U

(11) AU-B-23,382/77 -2-

chamber to be discharged through said annular space and returned to said fuel bowl.

COMMONWEAIJfH OF AUSTRALIA

Patents Act

COMPLETE SPECIFICATiON (ORIGINAL)

Class Int. Glass Application Number: Lodged:

Complete Specification Lodged: o S. Accepted: S

65 Published: VS/.

S S

Priority: OS 6* S S S 4. S Related Art. *5 S OS 0* S

APPLICANT'S REF.: JWRB/fl0 730 A-as S.Name(s) of Applicant(s): GMER~iJL MOiTORS~ COROR~ATION

**Address(es) of Applicant(s): G-rand Boulevard,

U1,72TED STATES Or, AhEMiICO

~*Actual Inventor(s): Rtmahmore Rowley Valeiuirie, Jr.

Address for Service is: PHILLIPS, ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 37-41 Queen Street Melbourne, Australia, 3000 Complete Specification for the invention entitled:

CARBLJRETTER ACo ET22IRkTOR T)1*TfP

The 'following statement is a full description of this invention, including the best mnethod of performing it known to applicant(s):

PIDOC 11

;jl 1472 4 I

This invention relates to carburetters and in part-i-cular to a carburetter accelerator pump. A carburetter according to th~e present invention has a fuel bowl from which a main metering orifice opens into a main fuel passage which extends to a fuel-- air mixture conduit, and an accelerator pump cavity with an inlet from said. fuel bowl and a discharge passage extending from the base of said c,,vity to said. mixture conduit; and an accelerator pump for the :~4:10 carburetter comprises an actuator stem which extends into said cavity, a pump head which is arranged in said cavity to form in the base thereof a pump chamber, said head having a central opening slidably receiving

said actuator stem, and a spring which extends between 13 said stem and said head for moving said head in a

direction to discharge said pump chamber and deliver fuel therefrom through said discharge passage to said conduit, but which is compressible to perm-it movement of said. stem in said pump discharging direction more rapidly than said head, said stem having an upwardly

facing annular shoulder engageable by a downwardly f~acing annular shoulder on said head and said shoulders being separable to form an annular space opening to said pump chamber upon a predetermined compression of 6aid. spring and separation of said shoulders to permit a portion of the fuel in said L~mp chamber to be discharged through said annular space.

The carburetter accelerator pump according to

the invention permits a portion of the fuel delivered

by the pump to be diverted back to the carburetter

fuel bowl whenever the carburetter throttle is moved

rapidly to the wide open throttle position. The

accelerator pnump actuator stem and the pump head

co-operate to form a relief valve which permits such

diversion.

The accelerator pump actuator stem is also

a. capable not only of co-operating with the pump head to

S99 form said relief valve but also of actuating a mechanical power enrichment valve.

The scope of the invention is defined by the

appended claims; and the invention and the mechod by

which it is to be performed are hereinafter particularly

described with reference to the accompanying drawings

in which:- S

Figure 1 is a schematic section of a carburetter

having oi-e embodiment of an accelerator pump according to the invention;

Figure 2 is an enlarged detail of the accelerator

pump of Figure 1, showing the relative positions of the

pump head, actuating stem, and mechanical power rp L_ enrichment valve as the carburetter throttle reaches the wide-open-throttle position; and

Figure 3 is a section on the line 3-3 of

Figure 2 showing relief passages in the pump head.

The drawing shows a carburetter 10 with a

mixture conduit 12 containing a venturi cluster 14

and a throttle valve 16. A fuel bowl 18 delivers fuel

through one or more main metering orifices 20 to a

main fuel passage 22 which opens into the venturi

10 cluster 14.

An accelerator pump 24, disposed in a pump

well 25, has an actuator stem 26 connected through a linkage 28 to a throtule valve shaft 30. As throttle

S" 16 is opened, linkage 28 uoves actuator stem 26

S 15 downwardly to discharge fuel from a pump chamber 32 formed in well 25 below pump 24 through a pump

discharge passage 54 into the mixture conduit 12. An

atmospheric vent 36 prevents siphoning of fuel through

aO. discharge passage 34, and a check valve 38 prevents S

air fron being drawn into pump chamber 32.

The lower end 40 of actuator stem 26 is slidably S. received in the central opening 41 of a pump head 42.

A duration spring 44 is retained between pump head 42

and a flarge 46 included as part of actuator stem 26.

Duration spring 44 thus biases pump head 42 downwardly

I so that a downwardly facing annular shoulder 48 within pump head 42 engages an upwardly facing annular shoulder 50 of actuator stem 26.

In operation, a return spring 52 pushes pump

head 42 upwardly and, thus acting through duration

spring 44, lifts actuator stem 26 as throttle 16 is

closed. As pump head 42 and actuator stem 26 move

upwardly, fuel is drawn from fuel bowl 18 through an

inlet passage 54, past a check valve 56, and into

10 pump chamber 32. When actuator stem 26 is moved

downwardly, spring 44 forces pump head 42 downwardly

S. to discharge fuel from pump chamber 32 through discharge

passage 534 However, when throttle 16 is moved very rapidly o 15 to the wide-open-throttle position, actuator stem 26

moves more rapidly than pump head 42. Pump head

annular shoulder 48 is then separated from actuator

stem annular shoulder 50, and the annular chamber 58

tAus formed therebetween then interconnects a plurality

of relief channels 60 formed about th inside of the

lower portion of pump head 42 with a plurality of channels 62 formed about the inside of the upper

portion of pump head 42. A portion of the fuel which

would otherwise be discharged through passage 54 is

then diverted through channels 60, chamber 58 and channels 62 to the portion of the pump well 25 above pump head 42 and is accordingly returned to fuel bowl 18.

Thus the amount of fuel delivered through

accelerator pump discharge passage 34 to mixture

conduit 12 during rapid movement of throttle 16 to

the wide-open-throttle position is less than that

delivered during gradual movement of throttle 16;

this reduction in accelerator pump delivery is

.0 desirable since the engine does not require as much we Sc

09 0 fuel under these conditions. 0

*6 QC An auxiliary metering orifice 66 opens from V a pump chamber 32 into main fuel passage 22 and is

controlled by a mechanical power enrichment valve

68. As actuating stem 26 approaches its lowermost

position that is, as throttle 16 approaches the

S. C wide-open-throttle position the lower end 40 of

*r S actuating stem 26 engages valve 68, moving it

downwardly against the bias of a spring 70 to permit

fuel to flow from fuel bowl 18 through inlet passage 0

54, pump chamber 32 and auxiliary metering orifice *r C

66 to main fuel passage 22. This additional fuel SO

flow provides an enriched mixture for power operation.

It will be seen that when, on rapid movement

of the throttle valve 16 to its fully open position,

i the actuator stem 26 moves from the positionl shown in Figure 1 to that shown in Figure 2, fuel will not be discharged through the annular space 58 and channels 62 until the shoulders 48 and 50 have separated from each other by a distance greater than that of a portion of the central opening, not provided with channels 58 or 62, within which the lower end 40 of stem 26 is a sliding fit.

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Claims (3)

The claims defining the invention are as follows:-

1. A carburetter in which a main metering orifice opens from a fuel bowl into a main -ael passage which extends to a fuel-air mixture conduit, and an accelerator pump cavity has an inlet from said fuel bowl and a discharge passage which extends from the base of said cavity to said mixture conduit; and in whichthe accelerator pump comprises an actuator stem

which extends into said cavity, a pump head which is or saf id c-cvi-/- 0 arranged in said cavity to form in the base/t4-e.ef a

pump chamber, said head having a central opening slidably receiving said actuator stem, and a spring which extends between said stem and said head for moving said head in a direction to discharge said pump chamber and deliver fuel therefrom through said

discharge passage to said conduit, but which is compressible to permit movement of said stem in said

pump discharging direction more rapidly than said head,

said stem having an upwardly facing annular shoulder 20 engegeable by a downwardly facing annular shoulder on S" said head, and said shoulders being separable to form

an annular space opening to said pump clamber upon a

predetermined compression of said spring andr Weer-m~7ed separation of said shoulders to pemit a portion of

4 4d 4 sai

the fuel in said pump chamber to be discharged

through said annular space/

2, A carburetter according to claim 1, in which

said stem has an elongated ower end which, over a

portion of its length, is a sL ding fit within said

central opening, said annular space formed by

separation of said shoulders opening to said pump

chamber only when the shoulders have separated by a

distance greater than the length of said portion.

S 10

3. A carburetter according to claim 1 or 2, in

which an auxiliary metering orifice c -ns into said a main fuel passage from the base of said cavity and a

power enrichment valve which controls flow through

said auxiliary orifice is engageable by the lower end

15 of the stem to displace said valve and permit fuel flow from said fuel bowl through said pump chamber

4.0 and said auxiliary orifice to said main fuel passage a as said stem nears the end of its downward movement.

0

4. A carburetter constructed and adapted to

20 operate substantially as hereinbefore particularly

described with reference to and as shown in the accompanying