US3658040A

US3658040A - Device for regulating the fuel flow of internal combustion engines

Info

Publication number: US3658040A
Application number: US859669A
Authority: US
Inventors: Andre Vuaille; Jean Pigeroulet
Original assignee: Sigma
Current assignee: Sigma
Priority date: 1968-09-20
Filing date: 1969-09-22
Publication date: 1972-04-25
Anticipated expiration: 1989-04-25
Also published as: DE1947631A1; GB1274739A

Abstract

The regulation device comprises a centrifugal regulator driven in rotation by the engine and provided with the a plate which can move along the axis of the regulator under the centrifugal effect of rotating balls. Return springs are provided for acting on the plate in the opposite sense to the action of the balls. The plate drives, in its axial movement, a rack for regulating the flow of the fuel pump, which rack is substantially parallel to the axis of the regulator. A lever articulated between the rack and the axis of the regulator is provided for co-operating with the rack and the plate, and for rotation, at least in one range of engine speeds, about its articulation, such that to an increase of engine speed corresponds an increase of the flow, whereas for all other speeds at which the regulation device intervenes an increase of the speed produces a decrease of the flow. One of the springs of the regulator acts more particularly against the plate in that range of speeds. In order that this spring has a well determined initial tension which does not depend on the tensions of the other springs, and in order that there is no reaction of this spring on the others, it is disposed such that one of its ends bears against a socket and its other end bears against a stop member which can slide on the socket and which is pushed by the spring against an abutment rigidly secured to the socket.

Description

United States Patent Vuaille et al.

[451 Apr. 25, 1972 [54] DEVICE FOR REGULATING THE FUEL FLOW OF INTERNAL COMBUSTION Primary -Wr i s ENGINES Attorney-Waters, Roditi, Schwartz & Nlssen [72] Inventors: Andre Vuaille, Lyon; Jean Plgeroulet, Vil- [57] ABSTRACT leurbanne both of France The regulation device comprises a centrifugal regulator driven [73] Assignee: Societe Industrlelle Generale De in rotation by the engine and provided with the a plate which Mecanique Appliquee S.I.G.M.A., Paris, can move along the axis of the regulator under the centrifugal France effect of rotating balls. Return springs are provided for acting on the plate in the opposite sense to the action of the balls. [22] Filed. Sept. 22, 1969 The plate drives, in its axial movement, a rack for regulating [21] APPL 9 9 the flow of the fuel pump, which rack is substantially parallel to the axis of the regulator. A lever articulated between the rack and the axis of the regulator is provided for co-operating Foreign Appllcauon pl'lol'ny Data with the rack and the plate, and for rotation, at least in one Sept 20 1968 France ..167083 range engine Speeds, abut articulatimi Such that Mar 25 1969 France ..6908796 increase engine Speed increase whereas for all other speeds at which the regulation device in- [52] U Cl tervenes an increase of the speed produces a decrease of the [51] flow. One of the springs of the regulator acts more particularly against the plate in that range of speeds. in order that this [58] Field of Search ..123/139, 140, l40l p g has awe determined initial tension which does not de pend on the tensions of the other springs, and in order that [56] References Cited there is no reaction of this spring on the others, it is disposed UNITED STATES PATENTS such that one of its ends bears against a socket and its other end bears against a stop member which can slide on the socket 2,096,203 10/1937 Schnurle et al. ..l23/l40 and Which is pushed by the Spring against an abutment rigidly 2,669,983 2/1954 Reddy et a1 ..l23/l40 Secured to the Socket 2,947,299 8/1960 Shallenberg et al. .....l23/14O 3,139,875 7/1964 Link 123/140 13 Claims, 14 Drawing Figures z & I28 20 z/ ENGlNE 91 lg F /2 l6 59 9 p /e J F- v nee 43 56 54 52 PATENTEDAPR 25 I972 3, 658,040

ENGINE fig; INVENTOR.

ica /04 BY 5/ F101 .5 Fmi 4 \m ATTORNEY DEVICE FOR REGULATING THE FUEL FLOW OF INTERNAL COMBUSTION ENGINES This invention relates to devices for regulating the flow of fuel per revolution, for an injection pump for an internal combustion engine, which comprises:

a centrifugal regulator or governor adapted to be driven by the engine, having an active element or actuating member movable along the axis of the regulator and having a first elastic means coaxial with the active element and bearing, at one end, against a cup which can be displaced axially by an accelerator,

an adjusting element or rack for adjusting the flow of the pump, movable along a direction substantially parallel to the axis of the centrifugal regulator,

and connection means between the active element and the rack adapted to drive the rack, in particular in the sense of a decrease of the flow when, for high speeds of revolution situated in a first range whose lower limit is equal to a speed called the cut-off speed, the active element is displaced in the sense of increasing speeds, these connection means comprising a lever whose point of articulation is situated between the axis of the centrifugal regulator and the rack,

a socket coaxial with the centrifugal regulator and adapted to come to bear against the other end of the first elastic means, at least when the speed of revolution is in or greater than the range of idling speeds,

a second elastic means bearing, at one of its ends, against that socket and adapted to be compressed by the active element against that socket, which (socket) is maintained immo-.

bile by the first elastic means when the speed is relatively low and is situated in a second range whose lower limit is in or greater than the idling range, the whole being such that, in this second range of speeds, the co-operation of the active element and the lever causes the rotation of this lever, and makes an increase of flow correspond to an increase of the speed of revolution.

These regulation devices fall in the category of any speed regulation devices, for they are such that, to each position of the accelerator, corresponds a determined speed of revolution of the engine.

This invention is more particularly, but not exclusively, concerned with those of these devices for regulating the flow of fuel which are intended for the engines of automobile vehicles.

In such regulation devices, it is important to avoid mutual reactions of the elastic means so that, when the characteristics of one of the elastic means are modified, the characteristics of another elastic means are not affected.

An object of this invention is to provide devices of the type concerned which fulfil better the requirements of practice, in particular with respect to the separation of the functions of each elastic means and the decrease of the mutual reactions of these elastic means.

In accordance with the present invention, an any speed" regulation device for regulating the flow of fuel per revolution, for an injection pump for an internal combustion engine, comprises the structure defined above, and is characterized by the fact that the second elastic means bears, at its other end, against a stop member which can slide on the socket, which stop member is pushed by the second elastic means against an abutment rigidly secured to the socket and which (stop member) can be moved away from the abutment by the active element when the speed of revolution has a value situated in the second range of speeds or greater than this second range.

Preferably, a third elastic means (called excess flow means) is provided and bears, at one of its ends, against the cup in order to move the active element away from that cup, the active element moving against the action of only this third elastic means for speeds of revolution between the zero speed and the idling range.

According to a first embodiment, the point of articulation of the above-mentioned lever is fixed with respect to the casing containing the regulation device and the connection means comprise moreover a radial arm connected in translation to the active element and traversed by the rack, this arm cooperating with the rack for speeds of revolution which are not in the second range of speeds, the socket and the stop member being mounted at the end of a rod guiding the first elastic means, which (first elastic means) bears permanently against the socket.

According to another embodiment, the point of articulation of the lever is fixed with respect to the socket and one end of the lever is articulated on an axis fixed on the stop member, the socket and the stop member being mounted at the interior of the active element, around the end of a rod guiding the first elastic means, which elastic means comes to bear against a ring adapted to co-operate with a shoulder of the socket.

Advantageously, in a regulation device of the type in question, one end of the lever co-operates with the active element an the other end of that lever is articulated on one end of a second lever, itself articulated on an axis fixed on a casing, the other end of this second lever being articulated on the rack, such that the axial components of the forces of inertia acting, on the one hand, on the active element of the centrifugal regulator, and on the other hand, on the rack, have opposite effects on the flow of fuel per revolution.

The invention will, in any case, be well understood with the aid of the following complementary description of two embodiments of the device according to the invention, given by way of example, with reference to the accompanying drawings.

In these drawings:

FIG. 1 shows'in solid lines a curve of the flow of fuel per revolution (Q) as a function of the speed of revolution (N), this curve being obtained with an injection pump provided with a regulation device in accordance with this invention. In this same FIG. 1, two curves in dot-dash lines represent the variations of the flow per revolution obtained with devices of the prior art. All these curves are drawn for the position of the accelerator corresponding to the maximum speed.

FIG. 2 is a longitudinal section of a regulation device constructed according to the first embodiment of the invention.

FIG. 3 is a partial section along IIIlII of FIG. 2.

FIG. 4 is a partial rear view of the device of FIG. 2.

FIGS. 5, 6, 7 and 8 show schematically certain elements of FIG. 2, in different relative positions which they occupy in the course of operation of the device.

FIG. 9 shows, similarly to FIG. 2, a device constructed according to the second embodiment of the invention.

FIG. 10 shows a partial section along X-X ofFIG. 9.

, FIG. 11 shows, in section along XI-XI ofFIG. 13, a modification of the device of FIG. 9.

FIG. 12 is a section along XIIXII of FIG. 11, the regulating element, the connection means and the accelerator fork being shown in a view from above.

FIG. 13 is a section along XIIIXIII of FIG. removed.

And FIG. 14 is a detail view showing the connection means ofthe device ofFIGS. 11 to 13.

The embodiment of FIGS. 2 to 8 will be considered first. With regard to the regulation device as a whole, it comprises the following elements.

A centrifugal regulator or governor 1, partially shown, is mounted on a coaxial shaft 2. This shaft is driven by an internal combustion engine (not shown). The regulator comprises an active element 3, or receiving plate, mounted free in translation with respect to the shaft 2 with which it rotates. A nonrotary sleeve 4, connected in translation with the receiving plate 3 by means of a thrust bearing 51, serves as an abutment for one end of a spring 5, called excess flow spring, whose other end bears against a cup 6. The spring 5, which constitutes the third elastic means, exerts on the sleeve 4 a force in the sense B which opposes a force in the sense A generated by the centrifugal effect on the balls 7 and transmitted to the sleeve 4 by the intermediary of the plate 3 and the thrust bearing 51.

11 with parts The cup 6 is mounted free in translation on a guide-rod 8 coaxial with the shaft 2 and carried by a casing 9. The position of this rod 8 is adjustable axially.

The guide-rod 8 carries a socket 10, free in translation and which, in one extreme position, abuts against a shoulder 11 rigidly secured to the rod 8, the shoulder 11 being advantageously adjustable in axial position. The socket is situated between a shoulder 12, carried by the sleeve 4, and the cup 6. 4

A first elastic means is advantageously constituted by two

springs

13 and 14 opposing any moving together of the cup 6 and the socket 10.-The spring 13, called high speed spring, comes into action only after a preliminary compression of the spring 14, called idling spring.

The tensions of the springs 5, l3 and 14 are adjustable by displacement of the cup 6 by means of a cam 15 rigidly secured to a shaft 16. The rotation of the shaft16 can be controlled by an accelerator actuated, for example, by the operator or driver of an automobile vehicle equipped with such a regulation device. Two adjustable abutments 17 and 18 are provided for limiting the stroke of the cam 15 respectively at low speeds and at high speeds.

An element for adjusting the flow of fuel per revolution of the pump feeding the engine is constituted by a rack 19 of axis parallel to that of the shaft 2. A displacement of the rack 19 in the sense PLUS" indicated by an arrow surmounted by the sign controls an increase of the flow per revolution. The sense MINUS" has been indicated by an arrow surmounted by the sign Connection means are provided between the receiving plate 3 (or the sleeve 4 connected in translation with that plate) and the rack 19. These connection means comprise a radial arm 20 connected to the sleeve 4 and traversed freely by the rack 19.

On the rack 19 two abutmcnts are provided on either side of the arm 20: a first abutment 21, rigid and connected to one end of the rack, and adjustable along the axis of the rack, and against which (abutment 21) the arm 20 is applied during a displacement of the sleeve 4 in the sense A; a second abutment, elastic, constituted by a spring 22, compressed between the arm 20 and a shoulder 23 carried by the rack.

A finger 24 controlled by the driver can come to co-operate with the rack 19 in order to displace this rack in the sense MlNUS" and to cause stopping of the engine.

The operation of such a device, which is known, is recalled hereafter. In the following explanation, it must be considered that the member 32, which will be described only later on, is

not provided in the-device of FIG. 2.

To start the engine, the driver first presses the accelerator as far as it will go i.e. until the cam 15 makes contact with the abutment 18. The cup 6 is moved towards the sleeve 4 and the spring 5, compressed, pushes to a maximum this sleeve in the sense B. The arm 20 pushes to a maximum the rack 19 in the sense PLUS by means of the spring 22. The flow per revolution of the pump is thus maximum at the moment when the engine is started by the starter.

This large flow facilitates the starting of the engine, but once the engine is started, the flow is too high and mustbe decreased or else a considerable amount of smoke will be produced. The engine, overfed, revolves by itself at a speed which increases. The centrifugal effect manifests itself and the balls 7 push the plate 3 and the sleeve 4 in the sense A thus compressing the spring 5 until the shoulder 12 comes to abut against the socket 10. The displacement of the sleeve 4 is transmitted to the rack 19 by the arm 20 which bears against the abutment 21. The rack is displaced in the sense MINUS" and the flow per revolution is decreased, which limits very rapidly the production of smoke.

When the shoulder 12 comes just into contact with the socket 10,-the supplementary flow for starting, called excess flow is completely eliminated. Once the engine has reached its idling speed N it would remain there if the cam 15 were bearing against the abutment l7, and this idling speed can be adjusted by displacement of that abutment 17.

But the cam 15 is maintained against the abutment 18, so that the flow per revolution of the pump at the moment when the engine passes through its idling speed N is sufficient to permit the engine to accelerate. The speed of the engine increases, but, as long as the force due to the centrifugal effect is not greater than the sum of the tensionsof the springs 5, l3 and 14, the sleeve 4 and the socket 10 will not be displaced axially. It is the same for the rack 19. The flow per revolution is no longer modified by the regulation device for an intermediary range of speeds.

At a speed N called the cut-off speed, the first range of speeds is reached, and the force due to the centrifugal effect becomes equal to the sum of the tensions of the

springs

5, 13 and 14, and, at that moment, the sleeve 4 and the socket 10 are displaced in the sense A thus driving the rack 19 in the sense MINUS," possibly until the flow drops to zero.

Since the cam 15 has displaced the cup 6 by the maximum, the cut-off speed corresponding to this position will be the maximum cut-off speed.

The curve 25 of the flow per revolution (Q) of the pump as a function of the speed of revolution (N) is drawn in dot-dash lines on FIG. 1. It will be noted that, for a piston-type pump, there is a constant ratio between the flow per revolution and the flow per piston stroke. It is immaterial that the curve be drawn with the flow per revolution as the ordinate, and not the flow per stroke.

Initially, for a very low speed of revolution, the flow per revolution is maximum, the representative point being 26. Until the idling speed N the regulation device acts, and the representative point moves as far as 27. The difference between the ordinates of the

points

26 and 27 corresponds to the initial excess flow, intended to facilitate the starting.

From the idling speed N to the cut-off speed N the representative point moves from 27 to 28 along an arc of natural flow of the pump corresponding to wide open running. The regulation no longer intervenes.

Finally, when the cut-off speed N is exceeded, the regulation intervenes to make the flow per revolution decrease; the arm 20 moves in the sense A and drives the rack 19 in the sense MINUS." It can be seen that with such a device, the choice of the flow per revolution at the nominal speed N of revolution of the engine, that is to say the choice of the ordinate of the point P, determines the ordinate of the point 27 since the arc 27, 28 is determined by the characteristics of the pump and of the hydraulic circuit, the point P being known.

1n particular, if the flow per revolution at the speed N is selected so as to obtain maximum torque at the limit of smoking for this speed N then at the speed N the limit of smoking will be exceeded and unburnt gases and smoke will be produced.

In order to reduce the smoke at the speed N one is thus normally obliged to decrease the flow per revolution at the speed N and hence to accept a reduction in the engine torque available at the speed N and in the power of the engine.

However, any speed regulation devices are known in which the connection means between the active element 3 and the rack 19 comprise a lever 30 whose point of articulation 31 is situated between the axis of the centrifugal regulator 1 and the rack 19. A second elastic means advantageously constituted by a helical spring 29 is disposed bearing, at one of its ends, against the socket and is adapted to be compressed by the active element 3 against the socket 10, which (socket 10) is maintained immobile by the

springs

13 and 14 when the speed of revolution is relatively low and is situated in a second range whose lower limit is equal to or greater than the idling speed N and whose upper limit is N, lower than N The whole regulation device is such that, in this second range of speeds between N, and N the co-operation of the active element 3 and the lever 30 causes the rotation of this lever 30 and makes an increase of flow correspond to an increase of the speed of revolution.

In FIG. 1, a curve 25a represents the variations of the flow as a function of the speed of revolution obtained with such devices. Between the abscissas N and N the arc of the curve 25a corresponds to the increase of the flow as a function of the speed. In this-manner, it ispossible to have a reduced fiow at the speed N and a maximal flow at the speed N But in the known devices which permit the curve 25a to be obtained to which curve does not correspond an excess flow during starting mutual reactions exist between the first and second elastic means, such that, if one modifies the pretension of the spring 29, in order to modify the abscissa N; of the ,point 47a corresponding to the speed of revolution above which the spring 29 begins to yield, this modification can affectthe tensions of the other elastic means. Conversely,

in order to maintain the abscissa of the point 47a constant, whatever be the .position of the accelerator cam 15, the variations of the tension of the first elastic means must not affect the pre-tension of the spring 29.

In order to remedy this disadvantage, in accordance with ,this invention, the second elastic means or spring 29 bears at its other endagainst a stop member 32 which can slide on the socket this stop member 32 is pushed by the second elastic means 29 against an abutment 33c rigidly secured to the socket 10 and can be moved away from the abutment 330 by the active element 3, when the speed of revolution has a value situated in the second range of speeds or greater than this second range.

The stop member or cup 32 and the cup 6 are situated on opposite sides of the socket 10. The cup 32 has the general shape of a hollow cylinder of revolution having a part 33 of smaller diameter and serving for the guiding of the cup 32 during its displacement. The spring 29 is disposed inside the cup 32 and comes to bear against a shoulder joining the part 33 and the rest of the cup 32. The part of the cup 32 the nearest to the shoulder 35 of the socket 10, against which socket 10 the

springs

13 and 14 bear, is constituted by a shoulder 34 in the form of a circular flange lying in a plane normal to the axis of the rod 8, and disposed between the shoulder 12 of the sleeve 4 and the shoulder 35 of the socket 10.

The shape of the cup 32 and the overall disposition appear in FIG. 2.

In the rest position of the overall device, the spring 29 maintains a separation X between the shoulders 34 and 35, the cup 32 then bearing against the abutment 33c by the intermediary ofanadjusting shim 33b. The abutment 33c can be constituted by a split ring, anchored in the socket 10. In this manner the spring 29 can receive an initial tension which does not produce any axial reaction on the socket 10, since the spring 29 is compressed between two abutments rigidly secured to the socket.

The shoulder 34 has an external diameter sufficient to cooperate with the shoulder 12 during the displacement in the sense A of the sleeve 4. At rest, a distance E (FIGS. 2 and 5) separates the shoulders 12 and 34.

The lever 30 is constituted by a plate which is substantially in the form of an elongated diamond, as visible in FIG. 2, and articulated at its center on the pin 31 fixed to the casing 9. The pin 31 is equidistant from the axes of the rod 8 and of the rack 19 and is normal to these latter two axes. One end of the lever 30 carries a fork 36, visible in FIG. 3, which can co-operate with a shoulder 37 of the rack 19; this shoulder 37 is adjustable in axial position and is constituted for example by a nut threaded on one end of the rack. The other end of the lever 30 carries a rounded head 38 which can abut against a lug 39 carried by the sleeve 4 (see FIGS. 2 and 3). In the rest position of the device, the head 38 and the lug 39 are separated by a distance F (FIG. 2).

A spring 40 tends to return the fork 36 in the sense MIN US" and, for example, connects to the casing 9 a point of the lever 30 situated substantially at mid-distance from the pin 31 and from the fork 36. The shoulder 37 is situated such that it co-operates with the fork 36 when this fork moves in the sense MINUS; the spring 40 thus also tends to return the rack 19 in the sense MINUS."

When the fork 36 moves in the sense PLUS, it does so freely without coming into abutment against any part whatsoever of the rack 19. Conversely, the rack 19 can move in the sense MINUS without abutting against the fork 36.

At rest, the lever 30, by acting on the shoulder 37, moves the abutment 21 away from the arm 20 by a distance 2 (FIG. 2), the force of the spring 40 being sufficient to overcome the force of the spring 22.

The pin 31 traverses the casing 9 and carries a control finger 41 (FIGS. 3 and 4), connected in rotation by a key and situated at the exterior of the casing. This finger 41, accessible to the driver of the vehicle, permits manual control of the rotation of the pin31 in the counter-clockwise sense (FIG. 2). This finger 41, at rest, is maintained bearing against an adjustable abutment 42 (FIGS. 3 and 4) by means of the spring 40.

A modification of the device according to this invention is shown in FIGS. 9 and 10.

According to this modification (FIGS. 9 and 10), the second elastic means 29a bears, at one end, against a socket or sleeve 4b, and, at its other end, against a stop member 4a, which stop member is pushed by the second elastic means 29a against an abutment 43 rigidly secured to the socket 4b.

The second elastic means 290 is constituted by a helical spring compressed between the socket 411 and the stop member 4a by the intermediary of adjusting shims 12b and 52a.

The socket or sleeve 4b is engaged in the stop member or sleeve 4a and traverses it. When the device is at rest, the sleeve 40 bears against the abutment 43 constituted by a split ring and an interval Xa (FIG. 9) separates the nearest faces of the sleeves 4a and 4b or of the shim 52a. The sleeve 4b has a shoulder adapted to co-operate with a ring 100, serving as an abutment for the springs 13a, 14a. The spring 5a bears against an interior shoulder of the sleeve 4b. The transmission lever 30a, which replaces both the arm 20 and the lever 30 of the device of FIG. 2, is articulated on the one hand on a shaft 31a approximately equidistant from the axes of the rack 19a and of the rod 8a and on the other hand on a shaft 44, parallel to the shaft 31a. The shaft 31a, normal to the plane of FIG. 9, is carried by the sleeve 4b. The shaft 44 is carried by the sleeve 40.

When the sleeves 4a and 4b are immobile one with respect to the other, the lever 30a acts like the arm 20.

When the sleeves 4a and 4b are in relative movement, the lever 30a acts like the lever 30 of the device of FIG. 2.

The operation of the regulation device shown in FIGS. 2 to 8 will now be considered.

When the engine is not running, the driver acts on the finger 41 so as to turn the lever 30 in the counter-clockwise sense (FIG. 5).

The fork 36 is no longer bearing against the shoulder 37 and the spring 22 pushes the rack 19 to the maximum in the sense PLUS," the shoulder 21 coming into abutment against the arm 20 (FIG. 5).

The driver depresses the accelerator as far as it will go so as to compress the spring 5 and to push the arm 20 in the sense B to the maximum. The cam 15 bears, in the high speed position, against the abutment 18. This position of the cam 15 will be maintained for the entire explanation. Thus, the cam 15 is only represented by its nose bearing against the cup 6, in FIGS. 6, 7 and 8.

The driver actuates the starter; the starting of the engine is facilitated by the large flow of fuel per revolution corresponding to the advanced position in the sense PLUS of the rack 19.

As soon as the engine turns by itself, it picks up speed, and the arm 20 pushes the rack 19 in the sense MINUS as already described and the flow per revolution decreases. On the curve in solid lines in Figure 1, one thus passes from a point 45 to a point 46 which corresponds to a position of the arm 20 in which the shoulder 12 comes into contact with the shoulder 34 (FIG. 6). The dis lacement of the arm 20 in the sense A takes place rapidly, even before the driver has released the lever 41.

Then, the driver releases this lever and the fork 36 is returned by the spring 40. The fork 36 comes to bear against the shoulder 37 and displaces the rack 19 in the sense MINUS by a distance Y 2X (see FIG. 7). The head 38 then comes into abutment against the lug 39 (FIG. 7). On the curve in solid lines of FIG. 1, one thus passes from the point 46 to the point 47.

Since the accelerator is in the high speed position, the flow per revolution corresponding to the point 47 is greater than that which is just necessary to maintain the idling speed N The speed thus continues to increase.

If the driver had completely released the accelerator, the cup 6 would be farther away from the socket 10, the cam 15 would be in contact with the abutment 17 and the

springs

5, 13 and 14 would be under less tension. The sleeve 4 would move in the sense A thus pushing the socket 10. The arm 20 would displace the rack 19 in the sense .MINUS until a flow per revolution sufficient to maintain the idling speed was reached. An equilibrium would be established for a point 48.

On the contrary, since cam 15 is in the high speed position, the sum of the forces of the

compressed springs

5, 13 and 14 is greater than the force of the spring 29. This spring 29 is calibrated such that it will yield when the speed of revolution reaches the value of the idling speed N (or a value slightly greater than the value of the idling speed).

Under these cofiditioiis, the shoulder 1215f the sleeve 4,51"

ready bearing against the shoulder 34, pushes this shoulder 34, and, with it, the cup 32 in the sense A thus compressing the spring 29, without displacing the socket 10. The movement of the cup 32 ceases when the shoulder 34 comes into contact with the shoulder 35 of the socket 10 (see FIG. 8), this taking place for the speed N During the recoil of the cup 32, the lug 39 has displaced the head 38 by the distance X in the sense A. The fork 36, accompanied in its movement by the rack 19, is thus displaced in the sense PLUS by the distance X since the head 38 and the fork 36 are situated on opposite sides of the pin 31. Simultaneously the arm 20, like the cup 32 and the sleeve 4, is displaced in the sense A by the distance X. As the distance Y is equal to 2X (see FIG. 7), the arm 2 comes into contact with the shoulder 21 of the rack 19 at the same time as the shoulder 34 comes into contact with the shoulder 35.

For this second range of speeds between N (or a speed greater than N and N, to the sense A of displacement of the sleeve 4 corresponds the sense PLUS" of displacement of the rack 19.

To an increase of speed of revolution corresponds an increase of flow per revolution, and, conversely, to a decrease of speed corresponds a decrease of flow. On the curve in solid lines in FIG. 1, one passes from the point 47 to the point 49.

From then on, the operation is similar to that already described previously.

With regard to the operation of the modification shown in Figures 9 and 10, the following points will be noted.

Contrary to the device of FIGS. 2 to 8, in this modified version the supplementary flow during starting (excess flow) is obtained automatically (elimination of the manual control). For the starting of the engine, the driver depresses the accelerator as far as it will go, in order to compress the springs a, 13:: and 14a, then he actuates the starter.

For speeds lower than N the spring 5a is compressed, but the spring 29a has a tension sufiicient to maintain the separation Xa between the sleeves 4a and 4b. The lever 30a thus remains immobile with respect to the sleeves 4a, 4b, and moves with the sleeves 4a and 4b, parallel to itself, in the sense A, thus driving the rack in the sense MINUS." In FIG. 1, the are 45-47 is described.

The shoulder 50 of the sleeve 4b then comes into contact with the ring a. The sleeve 4b is going to remain fixed, for the sum of the tensions of the springs 5a, 13a, 14a is greater than the tension of the spring 29a. The sleeve 4a moves in the sense A towards the sleeve 4b until it comes into abutment against that sleeve 4b, the spring 29a being compressed. The

pin 44 fixed on the sleeve 4a then moves, with respect to the pin 31a, in the sense A. The end 36a of the lever 30a moves in the sense B and drives the rack 19a in the sense PLUS. The arc of the curve 47-49 is then described.

The device will remain in the position corresponding to the position of the representative point 49, with the lever 30a inclined, until the cut-off speed N is reached.

At that moment, the sleeves 4a, 4b, the cup 10a and the lever 30a move as a unit in the sense A, thus driving the rack 19a in the sense MINUS.

By way of example, the following numerical values can be given (see FIG. 1), where rev. designates the number of revolutions of the engine:

N 500 rev./min.

N 1200 rev./min.

N maximum 3000 revJmin. Ordinate of the point 45 150 mmP/rev. Ordinate of the point 49 I00 mmflrev. Ordinate of the point 47 mm lrev. Ordinate of the point 48 20 mmflrev.

It is clear that all these numerical values are adapted to the characteristics of the engine for which the regulation device is intended.

In each of the embodiments described, the ordinate (flow per revolution) of the point 47 of the curve can be adjusted by the choice of the stroke X or Xa which can be adjusted by means of the shims 33b and 12b. This same point can be adjusted for a speed N; by varying the pre-tension of the springs 29 or 29a, by means of the shims 52 and 52a. These variations in the abscissa and the ordinate of the point 47 are obtained without modifying the other characteristic points of the curve.

The ordinate (flow per revolution) of the point 49 can be adjusted by means of the rod 8 or 8a which can be displaced in the sense PLUS or in the sense MINUS.

The speed N (abscissa of the point 49) can be adjusted by varying the stiffnesses of the springs 29 or 29a.

When a vehicle having an axis of travel D (FIGS. l1, l2, 13, 14) is equipped with a regulation device of the type concerned, and preferably according to the second embodiment described, and when the axis of the centrifugal regulator la and the rack 19a are substantially parallel to the direction D, the accelerations positive or negative (braking) having a component along the direction D act on the regulation device and tend to modify its action. Indeed, by reason of this component, the rack 19a and the plate 3a have a tendency to move in the same sense and the connection means of FIGS. 9 and 10 do not oppose this tendency. When the vehicle is travelling on an inclined terrain, the component of the acceleration of gravity along the direction D intervenes permanently, and the forces of inertia acting on the receiving plate 3a, the sleeves 4a, 4b and the rack 19a, modify the action of the device slightly, against the will of the driver. The term forces of inertia designates all the forces acting on the rack 19a and the active element or plate 3a, and which are connected to the accelerations, positive or negative, of gravity and/or of the vehicle on which the engine is mounted.

To remedy this disadvantage, the regulation device advantageously comprises connection means arranged such that the components along the direction D of the forces of inertia acting on the adjusting element 19a and the active element 30 have opposite effects on the flow of fuel per revolution.

Preferably, the connection means comprise a second lever 70 articulated, in its middle part, on a fixed pin 71, rigidly secured to the casing 9a, and, at its ends, respectively on the rack 19a and on the first lever 30a connected to the sleeve 4b and to the receiving plate 3a. This first lever 30a is articulated, at its end remote from the pin 44, on a pin 72; the lever 70 is also articulated on this pin 72, at one of its ends.

The levers 70 and 30a have their middle line oriented transversely to the direction D, and substantially perpendicular to the axes of the rack 19a and of the shaft 2.

As visible in FIG. 13, the pin 71 is situated substantially at mid-distance from the rack 19a and from the pin 31a.

This lever 70 is composed, in its middle part, of a cylindrical sleeve engaged on the pin 71, which sleeve carries at each of its ends two arms 73 and 74, diametrically opposed. The arm 73, offset towards the interior of the casing 90, comprises an endin the form of a fork articulated on the rack 19a. The arm 74, offset towards the nearest wall of the casing 9a, is articulated, at its end, on the pin 72.

The operation of this device is the following.

When the sleeves 4a, 4b move as a unit in the sense A, thus resting immobile one with respect to the other, the pins 44 and 31a move as a unit in the sense A. It is the same for the pin 72. As the pin 71 is fixed on the casing 9a, the lever 70 reverses the movement, and the movement of the end of the arm 73 takes place in the reverse sense to the movement of the end of the arm 74. Since this latter end moves with the pin 72 in the sense A, the end of the arm 73 and the rack 19a are going to move in the sense to which must correspond a decrease of flow per revolution and which is opposite to the sense A. The sense MINUS" of the displacement of the rack is thus opposite to the sense A.

To the sense B of displacement of the receiving plate 3a and of the sleeves 4a, 4b will correspond a sense PLUS of displacement of the rack opposite to the sense B. When the sleeves 4a and 4b enter into relative movement, for example when the sleeve 4a moves towards the sleeve 4b in the sense A, thus compressing the spring 29a, the pin 44 moves with respect to the pin 31a in the sense A. The lever 30a turns about the pin 31a and the pin 72 moves in a sense opposite to the sense A with respect to the pin 31a. The lever 70 again reverses the movement, and finally the rack 19a moves in the sense A, or, according to the designation adopted for the senses of displacement of the rack, in the sense PLUS.

To the sense B will correspond the sense MINUS.

It will be recalled that the sleeves 4a and 4b are immobile one with respect to the other for speeds of revolution lower than N R (or a speed slightly greater than N or greater than N and that these sleeves move one with respect to the other for speeds of revolution between N (or a slightly higher value) and N,

In the following explanation, it is assumed that the sleeves 4a and 4b bear one against the other, that is to say that the speed of rotation is greater than N which is practically always the case for a vehicle which is running.

It will also be assumed that the vehicle is subjected to a general acceleration parallel to D, in the sense B for example.

By inertia, the receiving plate 30 and the sleeves 4a and 4b are going to have a tendency to move in the opposite sense, that it to say in the sense A, with respect to the casing 9a fixed to the vehicle.

Similarly, the rack 19a is going to have a tendency to move in the sense PLUS identical to the sense A.

Now, since the sleeves 4a and 4b move as a unit, thus remaining immobile one with respect to the other, to a tendency of these sleeves to move in the sense A corresponds a tendency of the rack to move in the sense MINUS, that is to say precisely in the opposite sense to the sense towards which the rack 19a tends to move under the effect of its inertia.

One can advantageously choose the position of the pin 71 such that the opposite moments, about that pin, of the forces of inertia developed on the lever 70 by the rack 19a and the unit formed by the receiving plate 30 and the sleeves 4a and 4b, are equal in absolute value, in which case the effects compensate each other perfectly and the components of acceleration along the direction D have no influence on the flow of fuel per revolution.

When the vehicle is travelling on an inclined terrain, even if the speed of the vehicle is constant so that the acceleration of the vehicle as a whole is zero, the rack 19a and the unit formed by the receiving plate 3a and the sleeves 4a and 4b remain subjected to the component of the gravity in the direction D. The previous explanation remain valid and the effects of this component of gravity on the flow of fuel oppose each other and can, for an advantageous position of the pin 71, annul each other.

Regulation devices according to this invention fulfil the object that it was proposed to attain, namely:

separation of the functions of each elastic means,

decrease of the mutual reactions of the elastic means.

Indeed, one spring is intended, individually, for each function: idling (14, high speed (13, 13a), excess flow" (5, 5a) and increase of the flow with the speed (29, 29a).

Moreover, the arrangement is such that one can modify the pre-tensions of each spring without producing any reaction on the other springs.

What we claim is:

1. In an injection pump of an internal combustion engine, having a nominal speed of revolution N a device for regulating, for maximum torque with minimum smoking, at idling speeds, the flow of fuel per revolution Q when the speed of revolution N of the engine is situated in ranges of speed comprising a first or high speed range whose lower limit is an adjustable cut-off speed N and a second or idling range whose lower limit is a preset idling speed N and whose upper limit is a speed N, N always being less than N said device comprising a casing,

a shaft driven by the engine and extending into the casing,

a centrifugal governor mounted coaxially on said shaft, rotatable thereby and axially slidable thereon within the casing and comprising an actuating member coaxial with and movable along the shaft,

a guide-rod fixed to the casing coaxially with said shaft,

first elastic means coaxially positioned on the guide-rod,

a cup coaxially mounted on the guide-rod and so as to be displaceable axially by an accelerator member of the engine, one end of said first elastic means bearing against said cup,

an adjusting element arranged within the casing to adjust the flow per revolution of the pump by moving along a direction substantially parallel to the axis of rotation of the governor,

connection means connecting said actuating member with said adjusting element,

a socket borne coaxially at the other end of the guide-rod and arranged to bear against the first elastic means when N is greater than N second elastic means supported coaxially at said other end of the guide-rod and having one end bearing resiliently against said socket,

a stop member arranged to slide coaxially on said socket, the second elastic means bearing, at its other end, against said stop member so as to tend to increase axially the space between it and the socket, 1

an abutment rigidly secured to the socket against which abutment said stop member is urged by the second elastic means when N is less than N said stop member being urged away from the abutment by axial thrust against it of said centrifugally driven actuating member when N is greater than N the first and second elastic means being selected so that only when N has increased to N does said stop member abut against said socket whereupon said connecting means and said socket can move in unison at and above C,

whereby said device operates to decrease Q by reducing the flow per revolution of the pump when N is in the first range and increasing, and, on the other hand, to increase 0 by increasing the flow per revolution of the pump when N is in the second range and increasing.

2. Device according to claim 1, including a third elastic means, called excess flow" elastic means, which bears, at one of its ends, against the cup, so as to move the actuating member away from said cup, and coupling means between the actuating member and the adjusting member adapted to be moved by the actuating member against the action of only this third elastic means for speeds of revolution between the speed zero and the idling range.

3. Device according to claim 2, wherein the connection means comprise a lever, an articulation of said lever to said casing, and the coupling means comprise a radial arm connected in translation to the actuating member and traversed by the adjusting element, said arm cooperating with said adjusting element for speeds of revolution outside said second range of speeds.

4. Device according to claim 2, wherein the point of articulation of said lever is fixed with respect to the socket, including a pin on which one end of the lever is articulated fixed n the stop member, thesocket and the stop member being mounted inside the actuating member about the end of the guide-rod, and a ring cooperating with a shoulder of the socket, against which ring said stop member comes to bear.

5. Device according to claim 3, wherein one of the ends of the lever cooperates with the actuating member, and the other end of the lever cooperates with the adjusting element.

6. Device according to claim 1, wherein said connection means are arranged so that the axial components of the forces of inertia acting on the one hand on the actuating member and on the other hand on the adjusting element have opposite effects on the flow per revolution of the pump.

7. Device according to claim 4, wherein said connection means are arranged so that the axial components of the forces of inertia acting on the one hand on the actuating member and on the other hand on the adjusting element have opposite effects on the flow per revolution of the pump.

8. Device according to claim 7, wherein one of the ends of the lever cooperates with the actuating member, and the other end of the lever is articulated on one end of a second lever, itself articulated on a pin fixed on the casing, the other end of this second lever being articulated on the adjusting element.

9. Device according to claim 1, wherein the first elastic means is constituted by two helical springs disposed in parallel, namely a first spring adapted to act at idling speeds, and a second spring adapted to act at the high-speed range.

10. Device according to claim 4, comprising screw means for adjusting the position of the guide-rod.

11. Device according to claim 5, comprising means for ad justing the position of the guide-rod.

12. Device according to claim 1, including shims arranged to adjust the tension of the second elastic means.

13. Device according to claim 1, wherein the second elastic means is constituted by a helical spring.

Claims

1. In an injection pump of an internal combustion engine, having a nominal speed of revolution No, a device for regulating, for maximum torque with minimum smoking, at idling speeds, the flow of fuel per revolution Q when the speed of revolution N of the engine is situated in ranges of speed comprising a first or high speed range whose lower limit is an adjustable cut-off speed Nc and a second or idling range whose lower limit is a preset idling speed NR and whose upper limit is a speed NL, NL always being less than Nc, said device comprising : a casing, a shaft driven by the engine and extending into the casing, a centrifugal governor mounted coaxially on said shaft, rotatable thereby and axially slidable thereon within the casing and comprising an actuating member coaxial with and movable along the shaft, a guide-rod fixed to the casing coaxially with said shaft, first elastic means coaxially positioned on the guide-rod, a cup coaxially mounted on the guide-rod and so as to be displaceable axially by an accelerator member of the engine, one end of said first elastic means bearing against said cup, an adjusting element arranged within the casing to adjust the flow per revolution of the pump by moving along a direction substantially parallel to the axis of rotation of the governor, connection means connecting said actuating member with said adjusting element, a socket borne coaxially at the other end of the guide-rod and arranged to bear against the first elastic means when N is greater than NR, second elastic means supported coaxially at said other end of the guide-rod and having one end bearing resiliently against said socket, a stop member arranged to slide coaxially on said socket, the second elastic means bearing, at its other end, against said stop member so as to tend to increase aXially the space between it and the socket, an abutment rigidly secured to the socket against which abutment said stop member is urged by the second elastic means when N is less than NR, said stop member being urged away from the abutment by axial thrust against it of said centrifugally driven actuating member when N is greater than NR, the first and second elastic means being selected so that only when N has increased to NL does said stop member abut against said socket whereupon said connecting means and said socket can move in unison at and above Nc, whereby said device operates to decrease Q by reducing the flow per revolution of the pump when N is in the first range and increasing, and, on the other hand, to increase Q by increasing the flow per revolution of the pump when N is in the second range and increasing.

2. Device according to claim 1, including a third elastic means, called ''''excess flow'''' elastic means, which bears, at one of its ends, against the cup, so as to move the actuating member away from said cup, and coupling means between the actuating member and the adjusting member adapted to be moved by the actuating member against the action of only this third elastic means for speeds of revolution between the speed zero and the idling range.

4. Device according to claim 2, wherein the point of articulation of said lever is fixed with respect to the socket, including a pin on which one end of the lever is articulated fixed on the stop member, the socket and the stop member being mounted inside the actuating member about the end of the guide-rod, and a ring cooperating with a shoulder of the socket, against which ring said stop member comes to bear.

11. Device according to claim 5, comprising means for adjusting the position of the guide-rod.