US3650257A

US3650257A - Fuel control apparatus

Info

Publication number: US3650257A
Application number: US25228A
Authority: US
Inventors: John Peter Soltau; Robert Edward Kelly
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-04-14
Filing date: 1970-04-02
Publication date: 1972-03-21
Anticipated expiration: 1989-03-21
Also published as: DE2017385A1; FR2039170A1; GB1300747A; FR2039170B1

Abstract

An apparatus for controlling the fuel supply to an engine by adjustment of the control stop of a fuel injection metering pump has a three-dimensional cam whose angular and axial positions are variable in response to engine operating conditions, for example intake manifold pressure and throttle lever position. A cam follower for the three-dimensional cam in turn rotates a twodimensional cam. A further cam follower, for the two-dimensional cam, can be moved along the two-dimensional cam in response to a third engine operating condition, for example the position of the engine choke control. The resultant position of the further cam follower is transmitted to the control stop of the metering pump.

Description

United States Patent Soltau et al.

[151 3,650,257 [451' Mar. 21, 1972 [54] FUEL CONTROL APPARATUS [21] Appl. No.: 25,228

[30] Foreign Application Priority Data Apr. 14, 1969 Great Britain ..18,905/69 [5 6] References Cited 7 UNITED STATES PATENTS 2,984,228 5/1961 Braun etal. ..123/140.31

3,146,770 9/1964 Garcea ..l23/l40.3l

FOREIGN PATENTS OR APPLICATIONS 1,202,171 7/1959 France ..l23/l40.3l

Primary Examiner-Laurence M. Goodridge Attorney-Holman & Stern [5 7] ABSTRACT An apparatus for controlling the fuel supply to an engine by adjustment of the control stop of a fuel injection metering pump has a three-dimensional cam whose angular and axial positions are variable in response to engine operating conditions, for example intake manifold pressure and throttle lever position. A cam follower for the three-dimensional cam in turn rotates a two-dimensional cam. A further cam follower, for the two-dimensional cam, can be moved along the twodimensional cam in response to a third engine operating condition, for example the position of the engine choke control. The resultant position of the further cam follower is transmitted to the control stop of the metering pump.

13 Claims, 6 Drawing Figures PATENTEDMARm m2 SHEET 1 OF 5 IVENTOR 62m BM rim ATTORNEYS PATENTEDMAR21 I972 3,650,257

SHEET 5 [IF 5 El: ENGINE 51 /77 L. Z METERING DISTRlESUTOR 49 H ATTORNEYS FUEL CONTROL APPARATUS This invention relates to apparatus which controls a shuttletype metering pump in a fuel injection system for an engine by varying the position of the control stop of the said pump.

According to the invention an apparatus for controlling a shuttle-type metering pump in a fuel injection system for an engine comprises a three-dimensional cam whose angular and axial positions are respectively alterable, in use, in accordance with first and second engine operating conditions, a first cam follower coacting with the three-dimensional cam, a twodimensional cam movable by the first cam follower, a second cam follower engaging the two-dimensional cam and movable relative thereto in response to a third engine operating condition, and means for transmitting the position of the second cam follower to a control stop on the metering pump.

An apparatus in accordance with the invention will now be described by way of example and with reference to the following drawings in which:

FIG. 1 is a section through the apparatus;

FIG. 2 is a view on the line 2-2 in FIG. 1 with part of the casing removed for clarity;

FIG. 3 is a section on line 3-3 in FIG. 2;

FIG. 4 is a section on line 4-4 in FIG. 3;

FIG. 5 is a part view on line 55 in FIG. 2; and

FIG. 6 is a diagrammatic representation of a fuel injection system incorporating the apparatus shown in FIGS. 1 to 5.

A casing 10 includes an end cover 11 mounted thereon by means of screw 28. A diaphragm assembly 9 includes a diaphragm 12 sealingly engaged between the end cover 11 and the remainder of the casing 10, a dished plate 13, a first spring locating plate 14, a clamping plate 15, and a bolt 16 and nut 17 securing the assembly together.

An adjusting member 18 is threadedly engaged in the end cover 11 and supports a second spring locating plate 19. A compression spring 27 is mounted between the plates 14, 18. The adjusting member 18 permits variation of the force exerted by the spring 27 for a given position of the diaphragm as sembly 9. A set screw 20 within the member 18 abuts the end of the bolt 16 and limits the travel in one direction of the diaphragm assembly 9. Lock nuts 21, 22 are threaded on to the member 18 and set screw 20 respectively. A cap 23 is attached to the end cover 11 by screws 24. The end cover 11 includes a through passage 25 in which is mounted a pipe connection 26.

The casing 10 includes an access plate 28 and a side cover 29. Within the casing 10 is a spindle 30 which carries a sleeve 31 rotatable on roller bearings 32. A plate 33 having an armate slot 34 is pivotally mounted on the sleeve 31 by a screw 35 to provide a crank arm for the sleeve 31. A screw 36 engages the sleeve 31 through the slot 34 to lock the plate 33 in a desired angular position relative to the sleeve 31. A pair of links 37 each have one end pivotally mounted on the plate 33 and the other end pivotally engaged with an eye bolt 38 threadedly mounted in the bolt 16. A compound surface cam 39 has bearing rings 40 mounted therein, the rings 40 being slidable on the sleeve 31. The cam 39 carries a set screw 41 one end of which engages an axial slot 42 in the sleeve 31 so as to allow axial movement but to prevent rotation between the sleeve 31 and the cam 39. A locknut 43 is threaded on the set screw 41. The cam 39 has two

flanges

44, 45 in spaced parallel relationship and having engaged therebetween a pin 46 carried at one end of an arm 47 which is rotatable by a shaft 48 journaled in the casing 10. The shaft 48 carries, externally of the casing 10, a lever 49 rotatable between a pair of substantially identical adjustable stops 50, 51.

A first cam follower 52 is supported on a spindle 53 journaled in the casing 10. Integral with the cam follower 52 is a bracket 54 on which a cam plate 55 is rotatably mounted about a pin 56 and secured by

screws

57, 58, whereby adjustment of the position of the cam plate 55 with respect to the bracket 54 may be effected. A spindle 59 journaled in the casing 10 is rotatable by means of an arm 60 biased in one direction by a spring 61 and urged in the other direction by a cam 62 coacting with adjustable screw 63 and which is itself rotatable by means of an integral arm 64 against a torsion spring 65.

The spindle 59 supports a bracketed arm 66 on which is mounted a pivot 67. The bracket 66 and pivot 67 respectively abut screw stops 68, 69 at corresponding extremities of rota tion of the spindle 59. A second cam follower 8, rotatable about the pivot 67 comprises a pair of arms 70, 71 maintained in spaced parallel relationship by a pair of domed studs 72, 73 which engage opposite sides of the cam plate 55 and a flanged roller 74 rotatably mounted between the arms 70, 71 and intermediate their ends.

The roller 74 bears upon an edge of the cam plate 55 and also upon a piston-like member 75 slidably mounted in the casing 10, and biased by external means (not shown) against the roller 74. The casing 10 includes an upstanding portion 76 which supports a shuttle-type metering pump 77 associated with a fuel-injection system for an engine and having a control stop 77a. A diaphragm seal 78 extends between the casing portion 76 and the member 75. The casing 10 also includes a port 79.

In use the pipe connection 26 is coupled to the inlet manifold of the associated engine downstream of the throttle 80 in the air intake 81 and the port 79 is open to atmospheric pressure. Pressure drop in the said manifold urges the diaphragm assembly 9 against the spring 27 and rotates the cam 39, via the links 37, plate 33, sleeve 31 and set screw 41, in a direction tending to result in an anticlockwise rotation of the first cam follower 52, as seen in FIG. 1.

The lever 49 is connected to the throttle control 84 of the associated engine in such a way that movement of the said throttle control to accelerate the engine moves the cam 39 axially, via the shaft 48, arm 49 and roller 46, in a direction tending to result in clockwise rotation of the first cam follower 52, as seen in FIG. 1.

The lever 64 is connected to the choke control 83 of the engine in such a way that movement of the choke to the engine starting position causes the cam 62 to rotate the lever 60 against the spring 61 and thereby to rotate the bracket 66 clockwise as seen in FIG. 1.

The member 75 coacts with the control stop 77a of the shuttle-type metering pump 77, whereby downward movement of the member 75 permits increased movement of the shuttle and hence increased fuel delivery to the injectors 82.

The angular position of the first cam follower 52 is transmitted to the cam plate 55 via the bracket 54. The position of the second cam follower 8 with respect to the cam plate 55 depends on the angular position of the bracket 66, and hence on the position of the choke. The position of the roller 74, and hence that of the member 75, depends therefore on the positions of the throttle and choke controls and the pressure in the engine inlet manifold.

For a given initial manifold pressure and choke positions, movement of the throttle to accelerate the engine will cause the second cam follower to rotate anticlockwise as seen in FIG. 1, and thereby cause the pump 77 to increase fuel delivery and so permit increase of the engine speed. The resulting variations in pressure in the inlet manifold cause adjustment of the position of the diaphragm assembly 9, and thereby also cause adjustment of the fuel delivery. An equilibrium condition will be reached for any throttle position when the force exerted on the diaphragm assembly 9 by the manifold pressure drop is equal to the force exerted by the spring 27. For any throttle position and manifold pressure there will therefore be a corresponding fuel delivery.

Operation of the choke control, resulting in clockwise rotation of the bracket 66, as seen in FIG. 1, results in a considerably increased fuel delivery for all positions of the throttle control and the manifold pressure drop.

The screw stop 68 limits the anticlockwise rotation of the bracket 66, as seen in FIG. 1, and hence limits the movement of the cam follower 8 in a direction which will urge the member 75 towards the pump 77, and thereby reduce fuel delivery. The screw stop 68 may therefore be used to adjust a minimum fuel delivery for slow running of the engine.

In an alternative method of use, the diaphragm assembly 9 may be made responsive to a pressure signal derived from the engine speed. There will in this case, for any combination of throttle position and engine speed, be a unique corresponding fuel delivery.

Having thus claimed our invention what we claim as new and desire to secure by Letters Patent is:

1. ln a fuel injection system of an internal combustion engine, a shuttle-type metering distributor for fuel having a control stop determining the fuel injection dosage and apparatus for controlling the position of said control stop comprising a housing, a compound surface cam, means mounting said compound surface cam for independent movement angularly about an axis and axially relative to the housing, means sensitive to a first engine operating condition displacing said compound surface cam angularly, means sensitive to a second engine operating condition displacing said compound surface cam axially, a first cam follower coacting with said compound surface cam, a cam plate movably mounted in the housing and coupled to the first cam follower for displacement relative to the housing thereby, a second cam follower engaging the cam plate mounted for movement in one direction by the cam plate and also movable in a transverse direction means sensitive to a third engine operating condition moving said second cam follower in transverse direction, and means displacing said control stop in accordance with the displacement of the second cam follower in said one direction.

2. An apparatus as claimed in claim 1 in which said means sensitive to a first engine operating condition comprises a diaphragm responsive to a pressure in an air intake manifold of the engine and operatively connected to the compound surface cam.

3. An apparatus as claimed in claim 2 which includes a sleeve upon which the compound surface cam is axially slidable, means for preventing relative angular movement between the sleeve and the compound surface cam, a crank element mounted on the sleeve and a link connecting the crank element to the diaphragm.

4. An apparatus as claimed in claim 3 which includes means for adjusting the relative angular positions of the crank element and the sleeve.

5. An apparatus as claimed in claim 4 which includes means for adjusting the relative positions of the diaphragm and the link.

6. An apparatus as claimed in claim 2 which includes a spring biasing the diaphragm against movement due to decrease in the pressure in the engine intake manifold.

7. An apparatus as claimed in claim 6 which includes means for varying the bias applied by the spring.

8. An apparatus as claimed in claim 2 which includes means for limiting movement of the diaphragm in response to a decrease in pressure at the engine intake manifold.

9. An apparatus as claimed in claim 3 in which said means sensitive to a second engine operating condition comprises a lever movable in response to the position of a throttle control for the engine and operatively connected to the compound surface cam.

10. An apparatus as claimed in claim 1 in which said means mounting said compound surface cam comprises a sleeve mounted for rotation about its axis and slidably supporting the compound surface cam, and means for preventing relative rotation between the sleeve and the compound surface cam, said means sensitive to a first engine operating condition comprises a diaphragm responsive to the pressure in an intake manifold of the engine and operatively connected to the sleeve, and said means sensitive to a second engine operating condition comprises a lever responsive to the position of a throttle control for the engine and operatively connected to the compound surface cam to move the latter relative to the sleeve.

11. An apparatus as claimed in claim 1 further comprising means pivotally mounting the cam plate, the cam plate being rotatable about said mounting means b the firstcam follower. 12. An apparatus as claimed m cam 11 in which said means sensitive to a third engine operating condition comprises a lever movable in response to the position of a choke control for the engine and operatively connected to the second cam follower to move the latter in said transverse direction which is transverse to the axis of said means pivotally mounting the cam plate.

13. An apparatus as claimed in claim 12 in which the means displacing the control stop comprises a piston member slidably mounted in the housing, engaging the second cam follower and operatively connected to the control stop, the piston being movable in a direction transverse both to the axis of said pivotal mounting means and to the direction of movement of the second cam follower by the choke control.

Claims

1. In a fuel injection system of an internal combustion engine, a shuttle-type metering distributor for fuel having a control stop determining the fuel injection dosage and apparatus for controlling the position of said control stop comprising a housing, a compound surface cam, means mounting said compound surface cam for independent movement angularly about an axis and axially relative to the housing, means sensitive to a first engine operating condition displacing said compound surface cam angularly, means sensitive to a second engine operating condition displacing said compound surface cam axially, a first cam follower coacting with said compound surface cam, a cam plate movably mounted in the housing and coupled to the first cam follower for displacement relative to the housing thereby, a second cam follower engaging the cam plate mounted for movement in one direction by the cam plate and also movable in a transverse direction means sensitive to a third engine operating condition moving said second cam follower in transverse direction, and means displacing said control stop in accordance with the displacement of the second cam follower in said one direction.

11. An apparatus as claimed in claim 1 further comprising means pivotally mounting the cam plate, the cam plate being rotatable about said mounting means by the first cam follower.

12. An apparatus as claimed in claim 11 in which said means sensitive to a third engine operating condition comprises a lever movable in response to the position of a choke control for the engine and operatively connected to the second cam follower to move the latter in said transverse direction which is transverse to the axis of said means pivotally mounting the cam plate.